Skip main navigation

Diabetic Cardiomyopathy Revisited

Originally publishedhttps://doi.org/10.1161/CIRCULATIONAHA.106.679597Circulation. 2007;115:3213–3223

    Abstract

    Diabetes mellitus increases the risk of heart failure independently of underlying coronary artery disease, and many believe that diabetes leads to cardiomyopathy. The underlying pathogenesis is partially understood. Several factors may contribute to the development of cardiac dysfunction in the absence of coronary artery disease in diabetes mellitus. This review discusses the latest findings in diabetic humans and in animal models and reviews emerging new mechanisms that may be involved in the development and progression of cardiac dysfunction in diabetes.

    The prevalence of diabetes mellitus is growing rapidly. It is estimated that globally the number of adults affected with diabetes will increase from 135 million in 1995 to 300 million by 2025.1 Patients with diabetes mellitus are at increased risk for cardiovascular diseases. Thus, cardiovascular complications are the leading cause of diabetes-related morbidity and mortality.2 Diabetes mellitus is responsible for diverse cardiovascular complications such as increased atherosclerosis in large arteries (carotids, aorta, and femoral arteries) and increased coronary atherosclerosis, which increases the risk for myocardial infarction, stroke, and limb loss. Microangiopathy contributes to retinopathy and renal failure and may contribute to cardiac pathology as well.3,4 Diabetes mellitus also can affect cardiac structure and function in the absence of changes in blood pressure and coronary artery disease, a condition called diabetic cardiomyopathy. This term was introduced 30 years ago by Rubler et al,5 who described 4 diabetic patients with congestive heart failure and normal coronary arteries. Since then, diabetic cardiomyopathy has been defined as ventricular dysfunction that occurs independently of coronary artery disease and hypertension. In addition, diabetic cardiomyopathy may be characterized by diastolic dysfunction, which becomes more apparent in the presence of hypertension or myocardial ischemia (discussed in detail in the next section).

    Human Studies

    Many epidemiological and clinical studies have suggested the existence of a diabetic cardiomyopathy in humans.2,6–9 Diabetes mellitus is a well-recognized risk factor for developing heart failure. Indeed, the Framingham Heart Study showed that the frequency of heart failure is twice in diabetic men and five times in diabetic women compared with age-matched control subjects.10 This increased incidence of heart failure in diabetic patients persisted despite correction for age, hypertension, obesity, hypercholesterolemia, and coronary artery disease. Studies using independent population databases have provided similar results, revealing increased heart failure rates in subjects with diabetes mellitus in cross-sectional analyses and increased risk for developing heart failure in prospective analyses, even after correction for confounding variables.11–13 Echocardiographic changes consistent with systolic dysfunction and left ventricular (LV) hypertrophy have been described in a number of studies of diabetic populations and may portend an increased risk for the subsequent development of heart failure, particularly in the presence of coexisting hypertension.14–18 Diabetic cardiomyopathy in humans also is characterized by diastolic dysfunction, which may precede the development of systolic dysfunction.19,20 Indeed, echocardiography performed in 87 patients with type 1 diabetes mellitus without known coronary artery disease revealed diastolic dysfunction with a reduction in early diastolic filling, an increase in atrial filling, an extension of isovolumetric relaxation, and increased numbers of supraventricular premature beats.21 In similar subjects with uncomplicated type 1 diabetes without clinically apparent macrovascular or microvascular complications, Carugo et al22 reported early structural and functional cardiac alterations such as increased LV wall thickness and LV mass index, an age-related decline in ejection fraction, and an age-related increase in diastolic diameter. Similar approaches in well-controlled subjects with type 2 diabetes have revealed a prevalence of diastolic dysfunction of up to 30%.23–25 The use of flow and tissue Doppler techniques suggests even higher prevalence of diastolic dysfunction (as high as 40% to 60%) in community surveys and in smaller studies of individuals with type 1 and type 2 diabetes without overt coronary artery disease.26–29

    Animal Studies

    In animal models of diabetes, several functional and structural alterations of the heart or in cardiac muscle have been documented. The Table summarizes representative findings on cardiac function using in vivo and ex vivo measurement techniques in a variety of type 1 and type 2 diabetic rodent models.30–61 In interpreting these results, we must consider differences in the animal models examined. Thus, in most studies of type 1 diabetes mellitus, diabetes is induced after administration of the pancreatic beta-cell toxin streptozotocin, and most studies of type 2 diabetes mellitus have been performed in genetic models of obesity and insulin resistance such as the Zucker fatty rat or db/db mice, both of which have mutations that impair leptin receptor signaling, or ob/ob mice, which lack leptin. Moreover, because diabetes mellitus develops at varying tempos in these models, it is important to bear in mind that studies performed in animals before the onset of diabetes may reflect changes that are secondary to the underlying obesity and insulin resistance, and studies performed after the onset of diabetes may reflect the added effects of hyperglycemia of various durations. Most studies have been performed in isolated perfused hearts and reveal depressed cardiac function (recently reviewed by Severson62 and more recently supported by other studies30,33,35,48,56,63–65). Fewer studies have reported normal function in vitro.66–68 In vivo studies in these rodent models have provided evidence for systolic and diastolic dysfunction by echocardiography,36,53,69 but in some studies using invasive LV catheterization in mouse models of obesity and diabetes mellitus, LV contractility as determined by dP/dt was initially increased and may reflect the impact of the increased plasma volume and perhaps sympathetic activation associated in part with the underlying obesity.35 These initial observations were further clarified by Van den Bergh et al,70 who assessed hemodynamic changes in db/db mouse hearts in vivo using a pressure–volume catheter. They observed decreased contractility using load-independent variables such as preload recruitable stroke work, but steady-state measurements of cardiac output and other load-dependent parameters were elevated in db/db mice compared with control mice because of favorable loading conditions, specifically increased preload and decreased afterload.

    In Vivo and Ex Vivo Data for Cardiac Dysfunction in Animal Models of Type 1 and Type 2 Diabetes Mellitus

    Type 1 Diabetes MellitusType 2 Diabetes Mellitus
    OVE 26NODBB ratsSTZAlloxanob/obdb/dbZF/ZDFGK
    Up and down arrows indicate increase and decrease, respectively. Numbers are references. OVE 26 indicates beta cell overexpression of calmodulin; NOD, nonobese diabetic; STZ, streptozocin; ZF/ZDF, Zucker fatty/Zucker diabetic fatty rats; and GK, Goto-Kakizaki rats.
    Heart rate34,52,58
    Systolic function465043,45,49,553930,46,53,5951,61
    Diastolic function465034,52,5843,45,49393630,35,46,53,5951,61
    LV hypertrophy33,483738
    ±dP/dt5034,52,5845,5532,3535
    Inotropic response39,5733
    Tolerance to ischemia3454,604131,40,4447,564247

    The impact of diabetes mellitus on ischemia/reperfusion injury in rodent models has been examined both in vitro and in vivo. Although some controversy exists on whether diabetic hearts are more susceptible to injury when analyzed ex vivo,31,56,60,71,72 most in vivo studies have supported a greater degree of reduction in LV function and accelerated LV remodeling in the hearts of diabetic animals after coronary artery ligation.40,42,44,54,73,74 Thus, it is likely that the diabetic milieu and associated changes in the myocardium sensitize the diabetic heart to dysfunction after ischemic injury. Studies in models of type 2 diabetes mellitus and insulin resistance suggest that insulin resistance per se might contribute to reduced myocardial recovery after ischemia. For example genetic models of obesity and insulin resistance such as Zucker rats and db/db mice and mice with diet-induced obesity and insulin resistance exhibit impaired recovery of cardiac function after in vivo coronary artery ligation.40,42,73 Changes may be independent of infarct size, which is unchanged in models fed high-fat diets74 but increased in db/db mice.44 Moreover, treatment of Zucker rats with insulin sensitizing agents such as thiazolidinedione improves postischemic recovery in vitro and in vivo.66,75,76 Uncoupling protein-diptheria toxin A transgenic mice, which are a model of insulin resistance and obesity without diabetes, also exhibit impaired functional recovery in vitro after ischemia.77 In contrast, postischemic recovery of isolated perfused hearts is normal in db/db mice at a time when they are obese and insulin resistant but before the onset of diabetes, whereas ischemic recovery is impaired after the onset of diabetes.31 Taken together, these data suggest that insulin resistance per se may increase the susceptibility of the rodent heart to ischemia/reperfusion injury and that the coexistence of hyperglycemia might exacerbate the phenotype.

    Important caveats exist when extrapolating findings obtained in animal models of diabetes to humans. For example, cardiac physiology such as heart rate is different in rodents and humans, and rodent models are less likely to develop atherosclerotic disease in coronary arteries and spontaneous ischemia, which exists in many humans with diabetes mellitus. Important differences also exist in the hormonal milieu and the concentrations of lipids. Finally, most animal studies are performed in animals with uncontrolled or poorly controlled diabetes, whereas most human subjects will be on some form of therapeutic intervention. Nevertheless, animal models provide the opportunity to conduct mechanistic studies, which in some cases have been confirmed in human studies.

    Pathogenesis of Diabetic Cardiomyopathy: Mechanisms

    The pathogenesis of diabetic cardiomyopathy is multifactorial. Several hypotheses have been proposed, including autonomic dysfunction, metabolic derangements, abnormalities in ion homeostasis, alteration in structural proteins, and interstitial fibrosis.78,79 Sustained hyperglycemia also may increase glycation of interstitial proteins such as collagen, which results in myocardial stiffness and impaired contractility.80–82 In this review, we focus on mechanisms that are involved in decreasing myocardial contractility in diabetes mellitus. These are (1) impaired calcium homeostasis, (2) upregulation of the renin-angiotensin system, (3) increased oxidative stress, (4) altered substrate metabolism, and (5) mitochondrial dysfunction.

    Impaired Calcium Homeostasis

    Intracellular calcium (Ca2+) is a major regulator of cardiac contractility. In the cardiomyocyte, Ca2+ influx induced by activation of voltage-dependent L-type Ca2+ channels on membrane depolarization triggers the release of Ca2+ via Ca2+ release channels (ryanodine receptors) of sarcoplasmic reticulum (SR) through a Ca2+-induced Ca2+ release mechanism. Ca2+ then diffuses through the cytosolic space to reach contractile proteins, binding to troponin C and resulting in the release of the inhibition induced by troponin I. By binding to troponin C, the Ca2+ triggers the sliding of thin and thick filaments, which results in cardiac force development and/or contraction. [Ca2+] then returns to diastolic levels mainly by activation of the SR Ca2+ pump (SERCA2a), the sarcolemmal Na+-Ca2+ exchanger, and the sarcolemmal Ca2+ ATPase.83 It has long been appreciated that calcium and other ion homeostasis is altered in diabetic cardiomyocytes (recently reviewed by Cessario et al84). The mechanisms by which disturbed calcium homeostasis alters cardiac function in diabetes include reduced activity of ATPases,85 decreased ability of the SR to take up calcium, and reduced activities of other exchangers such as Na+-Ca2+ and the sarcolemmal Ca2+ ATPase.86,87 Indeed, the SR Ca2+ store and rates of Ca2+ release and reuptake into SR were depressed in type 1 diabetic rat myocytes. The rate of Ca2+ efflux via sarcolemmal Na+-Ca2+ exchanger also was depressed. However, no change occurred in the voltage-dependent L-type Ca2+ channel current that triggers Ca2+ release from the SR. The depression in SR function was associated with decreased SR Ca2+ ATPase and ryanodine receptor proteins and increased total and nonphosphorylated phospholamban proteins.88 In the db/db mouse model of type 2 diabetes mellitus, Ca2+ efflux in the cardiomyocyte was reduced, SR Ca2+ load was depressed, ryanodine receptor expression was reduced, and Ca2+ efflux through the Na+-Ca2+ exchanger was increased.89 Furthermore, decreased cardiac expression of SERCA2a or the Na+-Ca2+ exchanger has been observed in type 190,91 and type 2 diabetes.92 Trost et al55 observed that transgenic mice overexpressing SERCA2a were protected from streptozotocin-induced cardiac dysfunction, suggesting that altered calcium handling contributes to impaired cardiac function in diabetes mellitus. Technical challenges are involved in performing similar studies in humans. Studies in humans with heart failure have focused on examining changes in expression levels of proteins or genes involved in calcium signaling or measuring calcium concentrations and SR Ca2+ uptake in cardiomyocytes isolated from failing hearts of transplant recipients at the time of surgery.93–95 Such analyses remain to be conducted in patients with diabetic cardiomyopathy. However, a recent study described depressed myofilament function as a result of decreased Ca2+ sensitivity in skinned fibers obtained from diabetic patients at the time of coronary artery bypass surgery.96 This limited clinical study supports previous studies in animals. However, more studies are required to characterize the mechanisms responsible for altered calcium handling in patients with diabetic cardiomyopathy.

    Activation of the Renin-Angiotensin System

    The role of activation of the renin-angiotensin system in the development of diabetic cardiomyopathy is well recognized.97,98 Angiotensin II receptor density and mRNA expression are elevated in the diabetic heart.99–101 Activation of the renin-angiotensin system during diabetes mellitus has been shown to be associated with increased oxidative damage and cardiomyocyte and endothelial cell apoptosis and necrosis in diabetic hearts,102 which contributes to the increased interstitial fibrosis. Blockade of the renin-angiotensin system in streptozotocin-treated rats attenuated cardiac dysfunction partially through restoration of sarcoplasmic calcium handling.103 In a parallel study, blockade of the renin-angiotensin system reversed diabetes-induced Ca2+ loading of the SR and depletion of ryanodine receptors.104 Inhibition of the renin-angiotensin system was shown to reduce reactive oxygen species (ROS) production in streptozotocin-induced diabetic rats, similar to the effect observed with antioxidant treatment.105 Moreover, treatment of spontaneously diabetic (BB) rats with the angiotensin-converting enzyme inhibitor captopril has a cardioprotective effect.106

    Increased Oxidative Stress

    Increased ROS production in the diabetic heart is a contributing factor in the development and the progression of diabetic cardiomyopathy107,108 (the Figure). Cumulative superoxide-mediated damage or cellular dysfunction results when an imbalance exists in ROS generation and ROS-degrading pathways. Increased ROS generation and impaired antioxidant defenses could both contribute to oxidative stress in diabetic hearts. Several groups have shown that ROS is overproduced in both type 1 and type 2 diabetes.32,69,109,110 Under physiological states, most of the ROS generated within cells arises from mitochondria. Whereas increased mitochondrial ROS generation has been shown in various tissues such as endothelial cells that are exposed to hyperglycemia,111 relatively few studies to date have directly measured mitochondrial ROS production in mitochondria obtained from diabetic hearts. However, overexpression of mitochondrial superoxide dismutase (Sod2) in the heart of a mouse model of type 1 diabetes mellitus reversed altered mitochondrial morphology and function and maintained cardiomyocyte function.112 Evidence also exists for increased production of ROS from nonmitochondrial sources such as NADPH oxidase or reduced neuronal nitric oxide synthase (NOS1) activity coupled with increased activation of xanthine oxidoreductase.113,114 Whereas evidence for increased ROS production in diabetes mellitus is reasonably strong, the effect of diabetes on antioxidant defenses in the heart is controversial. Thus, the activities/expression levels of glutathione peroxidase, copper/zinc superoxide dismutase, or catalase were either increased115–119 or decreased.120,121 Increased ROS generation may activate maladaptive signaling pathways, which may lead to cell death, which could contribute to the pathogenesis of diabetic cardiomyopathy.122 Increased ROS production was associated with increased apoptosis, as evidenced by increased in situ nick end-labeling (TUNEL) staining and caspase 3 activation in ob/ob and db/db hearts.32 In the same study, increased ROS also was associated with increased DNA damage and loss of activity of DNA repair pathways that declined more rapidly with age in diabetic versus control animals. Thus, increased ROS-mediated cell death could promote abnormal cardiac remodeling, which ultimately may contribute to the characteristic morphological and functional abnormalities that are associated with diabetic cardiomyopathy. In addition to causing cellular injury, increased ROS production might lead to cardiac dysfunction via other mechanisms. For example, increased ROS has been proposed to amplify hyperglycemia-induced activation of protein kinase C isoforms, increased formation of glucose-derived advanced glycation end products, and increased glucose flux through the aldose reductase pathways,111,123 which may all contribute in various ways to the development of cardiac complications in diabetes mellitus. Increased ROS also might contribute to mitochondrial uncoupling, which could impair myocardial energetics in diabetes. This aspect will be discussed in more detail later in this review. Strategies that enhance mitochondrial ROS scavenging systems have been shown to be efficacious in reducing diabetes-induced cardiac dysfunction. Overexpression of metallothionein,107,124 catalase,125,126 and manganese superoxide dismutase112 in the heart reversed diabetic cardiomyopathy in animal models of both type 1 and type 2 diabetes. Thus, strategies that either reduce ROS or augment myocardial antioxidant defense mechanisms might have therapeutic efficacy in improving myocardial function in diabetes mellitus.

    Potential contributors to the development of diabetic cardiomyopathy. Increased free FA (FFA) activates PPAR-α signaling, leading to the increased transcription of many genes involved in FA oxidation. Increased FA oxidation leads to the generation of ROS at the level of the electron transport chain. ROS, which also can be generated by extramitochondrial mechanisms such as NADPH oxidase, plays a critical role in several pathways involved in the pathogenesis of diabetic cardiomyopathy, including lipotoxicity, cell death, and tissue damage, as well as mitochondrial uncoupling and reduced cardiac efficiency. TG indicates triglycerides; GLUTs, glucose transporters; PDK4, pyruvate dehydrogenase kinase 4; MCD, malonyl-coenzyme A decarboxylase; MCoA, malonyl-coenzyme A; ACoA, acetyl-coenzyme A; ACC, acetyl coenzyme A carboxylase; CPT1, carnitine palmitoyl-transferase 1; PDH, pyruvate dehydrogenase; CE, cardiac efficiency; PKC, protein kinase C; and AGE, glycation end products.

    Altered Substrate Metabolism: Metabolic Cardiomyopathy

    Altered myocardial substrate and energy metabolism has emerged as an important contributor to the development of diabetic cardiomyopathy.127,128 Diabetes mellitus is characterized by reduced glucose and lactate metabolism and enhanced fatty acid (FA) metabolism.129,130 Despite an increase in FA use in diabetic hearts, it is likely that FA uptake exceeds oxidation rates in the heart, thereby resulting in lipid accumulation in the myocardium that may promote lipotoxicity.131–133 Lipid intermediates such as ceramide might promote apoptosis of cardiomyocytes, thus representing another mechanism that might lead to cardiac dysfunction.69

    Multiple mechanisms contribute to the substrate switching that characterizes the diabetic heart. These include increased delivery of FAs, decreased insulin signaling, and activation of transcriptional pathways such as the peroxisome proliferator–activated receptor-α (PPAR-α)/PGC-1 signaling network that regulates myocardial substrate use.134–137 Thus, activation of PPAR-α increases the expression of pyruvate dehydrogenase kinase 4, which reduces glucose oxidation. Concomitantly, PPAR-α activation increases the expression levels of genes such as CD36, which regulates cellular FA uptake, and malonyl CoA decarboxylase, which degrades malonyl CoA, thereby derepressing carnitine palmitoyl transferase-1 and stimulating mitochondrial FA uptake. In addition, genes involved in β-oxidation such as medium- and long-chain acyl CoA dehydrogenase and hydroxy acyl CoA dehydrogenase also are transcriptional targets of PPAR-α (the Figure).

    In young ob/ob and db/db mice, increased FA oxidation and decreased glucose oxidation rates were not associated with increased expression of PPAR-α, PGC-1, or its transcriptional targets.35 Myocardial glucose use is reduced as early as 10 days on a high-fat diet and is accompanied by reduced insulin signaling.138 Thus, early in the course of obesity, it is likely that changes in myocardial substrate use reflect changes in substrate availability such as increased myocardial delivery of FAs and triglycerides. The reciprocal reduction in glucose use probably reflects allosteric inhibition of glucose use in the face of an increase in FA use (Randle phenomenon). It also is possible that impaired insulin signaling may have independent effects to reduce myocardial glucose use, as was observed in the hearts of mice with cardiomyocyte-restricted deletion of insulin receptors.139 As caloric excess and/or obesity become more longstanding, activation of transcriptional pathways such as PPAR-α/PGC-1–mediated signaling increases the expression genes involved in FA oxidation and FA import such as carnitine palmitoyl transferase-1 and medium- and long-chain acyl CoA dehydrogenase and FA transporters such as FATP1 and CD36, which contributes further to the metabolic changes in these hearts (the Figure). A second mechanism that may contribute to increased myocardial FA uptake in type 2 diabetic rodents is redistribution of CD36 to the plasma membrane.140

    It is important to emphasize that in many in vitro studies, isolated perfused hearts are exposed to a simple mixture of 2 substrates, namely glucose and FAs. Studies using multiple substrates such as ketones and lactate in addition to glucose and FA indicate that isolated hearts from diabetic animals use less lactate as well and glucose67,141 and that the degree of FA use might be higher at low FA concentrations but not necessarily at high FA concentrations.142 A recent in vivo analysis using tracer techniques designed to determine in vivo metabolism of glucose and FA suggested that FA use might not necessarily be increased in vivo because of increased use of other substrates such as ketones and that increased FA use was driven by increased concentrations of FA in db/db mice. In fact, increased overall FA use was observed only under pseudofed conditions (glucose infusion) but not under fasting conditions. Importantly, these diabetic hearts demonstrated significant impairment in metabolic flexibility in terms of their ability to alter their substrate use when concentrations of metabolic substrates used by the heart were manipulated.143 This in vivo study confirms the existence of altered myocardial substrate use in diabetic hearts but raises important caveats that should be considered when the results obtained in isolated hearts are interpreted.

    An important question is whether the changes in patterns of substrate use that characterize diabetic hearts directly contribute to impaired cardiac function. Studies of short-term diabetes mellitus revealed that changes in substrate fluxes occurred coincidentally with impaired myocardial function.142 Moreover, in longstanding type 1 diabetes mellitus, insulin replacement increased glucose use, reversed many of the metabolic abnormalities associated with diabetes, and reversed myocardial dysfunction.144 In models of type 2 diabetes mellitus, results of therapeutic interventions on cardiac function and metabolism have been variable and dependent on the model. Treatment of Zucker diabetic rats with PPAR-γ agonists restored cardiac function and reversed lipotoxicity. In addition, an increase occurred in glucose metabolism that accompanied increasing cardiac function.63,69 This therapeutic approach had 2 major metabolic consequences. First, a nearly complete reversal of lipotoxicity took place. Second, glucose use increased. It is not possible from these studies to determine the relative contribution of increased glucose use versus a reduction in lipotoxicity to the increase in cardiac function. Studies in lipotoxic transgenic mouse models have shown that reversal of myocardial steatosis by overexpression of a human apolipoprotein B transgene145 or by an increase in leptin concentrations146 normalizes cardiac function. It should be noted that in contrast to other rodent models of type 2 diabetes mellitus, Zucker rats may have a limitation in FA oxidation particularly under conditions of increased FA supply.61 In transgenic mice that are null for the PPAR-α gene that also have reduced FA oxidative capacity, the reduction in contractile reserve can be reversed by increasing the delivery of glucose by transgenic overexpression of the GLUT1 glucose transporter.147 Thus, it is likely that switching to glucose and reducing lipotoxicity may both contribute independently to the beneficial effect of PPAR-γ agonist treatment in this model. In contrast, db/db mice have increased rates of FA oxidation, which increase further as FA supply is increased.35,148 Treatment of db/db mice at different ages with PPAR-α or PPAR-γ agonists failed to reverse cardiac dysfunction despite a reduction in FA oxidation and increased glucose use that occurred concomitantly with the normalization of systemic metabolic homeostasis.30,31,64 The lack of an immediate benefit of normalizing substrate metabolism in db/db mice might reflect the severity of diabetes in this model or the persistence of mitochondrial dysfunction that is not normalized by short-term correction of metabolic abnormalities and myocardial substrate flux rates. If this hypothesis is correct, then one would expect high-energy phosphate metabolism to remain depressed after short-term PPARγ or PPARα ligand treatment of db/db mice. Prevention of altered substrate metabolism in these mice by perinatal overexpression of the GLUT4 glucose transporter prevented cardiac dysfunction in db/db mice, suggesting that metabolic modulation to sustain glucose use might prevent cardiac dysfunction in this model of severe type 2 diabetes mellitus.53,59 However, to be effective in this model of severe diabetes, the metabolic modulation either has to occur early in the course of diabetes or has to be of long duration.

    An important recent contribution to our understanding of the metabolic disturbances associated with diabetes mellitus is the observation that increased myocardial FA use in diabetic mouse models is associated with increased myocardial oxygen consumption. Thus, cardiac efficiency, which is the ratio of energy output (cardiac work) to energy input (MV̇o2) is reduced in diabetic hearts.33,35,48,148 Whether reduced cardiac efficiency contributes to the development of diabetic cardiomyopathy is still unknown. However, reduced cardiac efficiency may render the heart more vulnerable to hemodynamic stress such as that which occurs during ischemia/reperfusion, when the coupling between oxygen consumption and ATP production is very important. It was recently demonstrated, for example, that the impairment in functional recovery of db/db mice after ischemia/reperfusion could be ameliorated by very high concentrations of insulin and glucose in perfusates, which increased glucose use and enhanced cardiac efficiency.149 A number of potential mechanisms exist for reduced cardiac efficiency in diabetic hearts. Some studies suggest that most of the oxygen wasting occurs for noncontractile processes.148 Increased expression of mitochondrial and cytosolic thioesterases also has been proposed to contribute to reduced cardiac efficiency by increasing futile cycling of FAs.150,151 We and others have focused on the possibility that mitochondrial uncoupling results in a reduction in cardiac efficiency in diabetes mellitus on the basis of an increase in uncoupling protein expression and/or activation.33,152,153

    Recent studies in humans have supported many of the mechanisms that have been elucidated in animal studies. Thus, positron emission tomography studies of subjects with type 1 diabetes mellitus revealed increased myocardial FA use and reduced glucose oxidation,154 supporting earlier studies that used invasive coronary sinus and arterial sampling to determine myocardial substrate balance.155 Altered metabolism in these type 1 diabetic patients was associated with increased myocardial oxygen consumption (MV̇o2) and increased concentrations of serum free FA. Using similar techniques, Peterson et al156 demonstrated increased FA oxidation and MV̇o2 and reduced cardiac efficiency in obese insulin resistant women. Cardiac efficiency was inversely associated with insulin resistance, glucose intolerance, and obesity. It is likely that these changes may contribute to the pathogenesis of decreased cardiac performance in obesity and insulin-resistant states. Treatment of type 2 diabetes mellitus with the PPAR-γ agonist rosiglitazone increased myocardial glucose uptake in patients with underlying coronary disease,157 and in another cohort of diabetic subjects, myocardial glucose uptake was positively correlated with LV function.158 Thus, it will be important in future studies to determine whether therapies that will correct abnormal myocardial substrate metabolism in diabetes mellitus will translate to lower prevalence of heart failure or improved long-term survival. We may need to await the generation of new classes of therapeutic agents, given concerns that PPAR-γ agonist therapy might increase the risk of heart failure that occurs on the basis of plasma volume expansion.159

    Mitochondrial Dysfunction

    Recent studies of mitochondria have reignited interest in a role for mitochondrial dysfunction in the pathogenesis of diabetic cardiomyopathy.153,160,161 Diabetes mellitus causes functional and structural alterations in mitochondria. Impaired mitochondrial function was initially reported almost 25 years ago when Kuo et al162 showed depressed state 3 respiration in db/db heart mitochondria. This study was followed by others showing reduced mitochondrial oxidative capacity in type 1 diabetes.163–166 We have recently demonstrated decreased mitochondrial respiration and reduced protein expression of the oxidative phosphorylation components in obese type 2 diabetic mice.33 These alterations contribute to cardiac dysfunction because they reduce ATP production, which we speculate will diminish myocardial high-energy phosphate reserves, thereby contributing to impaired myocardial contractility. In addition to reduced oxidative phosphorylation capacity, mitochondria from hearts of type 1 diabetic animals exhibit a lower creatine phosphate activity,167,168 lower ATP synthase activity,163 and lower creatine-stimulated respiration.169 Additional mitochondrial defects in diabetes also may play a role in the development of cardiac dysfunction. These defects include decreased mitochondrial calcium uptake164 attributed in part to enhanced permeability transition.170

    Mitochondrial dysfunction in diabetes may reflect in part transcriptional repression of genes involved in oxidative phosphorylation components but not genes involved in FA oxidation. Thus, a reduction in mRNA levels of cytochrome b and ATP synthase subunit 6 (mitochondria-encoded genes) was found in streptozotocin-induced diabetic hearts.171,172 This was associated with a reduction in the binding capacity of mitochondrial transcription factor A to mitochondrial DNA. In addition, proteomic analysis of the diabetic heart also revealed reduced expression of proteins of the electron transport chain, creatine kinase, and the voltage-dependent anion channel 1, whereas the expression of β-oxidation proteins was increased.119 These changes could lead to mitochondrial dysfunction in a number of ways. Increased β-oxidation will increase the delivery of reducing equivalents to the electron transport chain. However, a limitation in oxidative phosphorylation components might result in increased superoxide production, which in turn might uncouple mitochondria and reduce the efficiency of ATP generation, which compounds existing defects in respiratory capacity.33,153 Indeed, perfusion of ob/ob hearts with FAs clearly increased mitochondrial oxygen consumption in mitochondria from ob/ob mice that was associated with a further reduction in ATP generation, indicating mitochondrial uncoupling.33 We speculate that this occurs in part because of increased delivery of reducing equivalents from β-oxidation to an electron transport chain that is impaired. The net result is ROS-mediated mitochondrial uncoupling. It also is possible that mitochondrial uncoupling could represent an adaptive mechanism in diabetic hearts to reduce membrane potential and ROS. Future studies in which expression levels or the activity of proteins that mediate mitochondrial uncoupling is manipulated are required to clarify whether mitochondrial uncoupling is adaptive or maladaptive in diabetic hearts.

    Mitochondrial protein nitration (as an index of oxidative damage) was increased in hearts from alloxan-induced diabetes.173 Mitochondrial hydrogen peroxide production was increased and glutathione levels were reduced in diabetic hearts, and these changes were attenuated by rotenone, thereby suggesting a mitochondrial source for ROS.171,174 Oxidative stress may therefore alter mitochondrial proteins, leading to mitochondrial dysfunction. Overexpression of ROS-detoxifying proteins (metallothionein, catalase, and manganese superoxide dismutase) reverses mitochondrial dysfunction and cardiomyopathy induced by diabetes.107,112,126 These data suggest an important role for mitochondrial dysfunction in limiting myocardial high-energy phosphate metabolism in diabetes mellitus. Recent studies in humans have provided support for a role of mitochondrial dysfunction in diabetic cardiomyopathy. A reduction in the ratio of phosphocreatine to ATP has been observed in patients with type 1 and type 2 diabetes mellitus without clinically significant coronary artery disease and correlates with indexes of diastolic dysfunction and with levels of serum free FAs.175,176 It will be of great interest to see the results of studies that will evaluate the impact of various therapeutic strategies on myocardial energetics and long-term cardiovascular outcomes in patients with diabetes.

    Ultrastructural analyses have revealed increased mitochondrial proliferation in models of type 1166 and type 2 diabetes mellitus33 and even in mouse models of the metabolic syndrome.136 Whereas evidence exists that these mitochondrial changes might be driven in part by activation of the PGC1-α/PPARα gene regulatory pathways, it is important to note that the predicted consequence of increased PGC1-α signaling,177,178 although promoting mitochondrial biogenesis, might not be sufficient in the context of diabetes to increase oxidative phosphorylation component capacity. This is supported by studies in mice with transgenic overexpression of PGC1-α in which mitochondrial biogenesis can be dissociated from a proportionate increase in mitochondrial function.160,179 It also is likely that other signaling pathways may play an important role in promoting mitochondrial biogenesis in the heart, and these remain to be elucidated. Gene knockouts of critical mitochondrial proteins such as the adenine nucleotide translocase and mitochondrial transcription factor A lead to increased mitochondrial biogenesis and cardiac myopathies.180,181 Thus, additional studies to elucidate the nature of potential additional mechanisms that promote mitochondrial biogenesis in diabetes mellitus are warranted. The other important conclusion that can be drawn from the studies performed to date is that an increase in cardiac mitochondria in diabetes does not necessarily imply an increase in myocardial energetics.

    Summary and Perspectives

    Diabetes mellitus is a growing public health problem that needs to be tackled at multiple levels such as prevention and health maintenance and aggressive management of associated comorbidities such as obesity, hypertension, and dyslipidemia. Cardiovascular disease remains the leading cause of mortality and morbidity in individuals with diabetes. The belief is widely held that the increase in cardiovascular mortality is a consequence of accelerated atherosclerosis. However, compelling epidemiological and clinical data indicate that diabetes mellitus increases the risk for cardiac dysfunction and heart failure independently of other risk factors such as coronary disease and hypertension. It is clear that coexisting morbidities accelerate the likelihood of developing cardiac dysfunction in diabetes. Recent research in humans and animals has provided novel insights into underlying molecular and pathophysiological mechanisms that increase the vulnerability of the diabetic heart to failure. It is hoped that as the mechanisms responsible for diabetic cardiomyopathy continue to be elucidated, they will provide the impetus for generating novel therapies tailored to reduce the risk of heart failure in individuals with diabetes mellitus, who will contribute significantly to a growing burden of heart failure that might accompany the growing epidemic of diabetes.

    This article is the second in a series on the topic of ″Targeting Metabolism as a Therapeutic Approach for Cardiovascular Disease.″

    We acknowledge the other members of the Abel Laboratory who have contributed to the studies cited in this review.

    Sources of Funding

    Dr Boudina has been supported by postdoctoral fellowships from the Juvenile Diabetes Foundation and is currently in receipt of a postdoctoral fellowship from the American Heart Association. Dr Abel is an Established Investigator of the American Heart Association. Research studies in the Abel Laboratory that have contributed to this review were supported by National Institutes of Health grants UO1HL70525, UO1 HL087947 (both Animal Models of Diabetes Complications Consortium), RO1 HL70070, and RO1 HL73167.

    Disclosures

    None.

    Footnotes

    Correspondence to E. Dale Abel, Division of Endocrinology, Metabolism and Diabetes, Program in Human Molecular Biology and Genetics, 15 N 2030 East, Bldg 533, Room 3410B, Salt Lake City, UT 84112. E-mail

    References

    • 1 King H, Aubert RE, Herman WH. Global burden of diabetes, 1995–2025: prevalence, numerical estimates, and projections. Diabetes Care. 1998; 21: 1414–1431.CrossrefMedlineGoogle Scholar
    • 2 Garcia MJ, McNamara PM, Gordon T, Kannel WB. Morbidity and mortality in diabetics in the Framingham population: sixteen year follow-up study. Diabetes. 1974; 23: 105–111.CrossrefMedlineGoogle Scholar
    • 3 Iltis I, Kober F, Dalmasso C, Cozzone PJ, Bernard M. Noninvasive characterization of myocardial blood flow in diabetic, hypertensive, and diabetic-hypertensive rats using spin-labeling MRI. Microcirculation. 2005; 12: 607–614.CrossrefMedlineGoogle Scholar
    • 4 Fein FS. Diabetic cardiomyopathy. Diabetes Care. 1990; 13: 1169–1179.CrossrefMedlineGoogle Scholar
    • 5 Rubler S, Dlugash J, Yuceoglu YZ, Kumral T, Branwood AW, Grishman A. New type of cardiomyopathy associated with diabetic glomerulosclerosis. Am J Cardiol. 1972; 30: 595–602.CrossrefMedlineGoogle Scholar
    • 6 Kannel WB, Hjortland M, Castelli WP. Role of diabetes in congestive heart failure: the Framingham study. Am J Cardiol. 1974; 34: 29–34.CrossrefMedlineGoogle Scholar
    • 7 Fein FS, Sonnenblick EH. Diabetic cardiomyopathy. Prog Cardiovasc Dis. 1985; 27: 255–270.CrossrefMedlineGoogle Scholar
    • 8 Fein FS, Sonnenblick EH. Diabetic cardiomyopathy. Cardiovasc Drugs Ther. 1994; 8: 65–73.CrossrefMedlineGoogle Scholar
    • 9 Zarich SW, Nesto RW. Diabetic cardiomyopathy. Am Heart J. 1989; 118: 1000–1012.CrossrefMedlineGoogle Scholar
    • 10 Kannel WB, McGee DL. Diabetes and cardiovascular disease: the Framingham study. JAMA. 1979; 241: 2035–2038.CrossrefMedlineGoogle Scholar
    • 11 Bertoni AG, Tsai A, Kasper EK, Brancati FL. Diabetes and idiopathic cardiomyopathy: a nationwide case-control study. Diabetes Care. 2003; 26: 2791–2795.CrossrefMedlineGoogle Scholar
    • 12 Nichols GA, Hillier TA, Erbey JR, Brown JB. Congestive heart failure in type 2 diabetes: prevalence, incidence, and risk factors. Diabetes Care. 2001; 24: 1614–1619.CrossrefMedlineGoogle Scholar
    • 13 Aronow WS, Ahn C. Incidence of heart failure in 2,737 older persons with and without diabetes mellitus. Chest. 1999; 115: 867–868.CrossrefMedlineGoogle Scholar
    • 14 Bella JN, Devereux RB, Roman MJ, Palmieri V, Liu JE, Paranicas M, Welty TK, Lee ET, Fabsitz RR, Howard BV. Separate and joint effects of systemic hypertension and diabetes mellitus on left ventricular structure and function in American Indians (the Strong Heart Study). Am J Cardiol. 2001; 87: 1260–1265.CrossrefMedlineGoogle Scholar
    • 15 Ilercil A, Devereux RB, Roman MJ, Paranicas M, O’Grady MJ, Welty TK, Robbins DC, Fabsitz RR, Howard BV, Lee ET. Relationship of impaired glucose tolerance to left ventricular structure and function: the Strong Heart Study. Am Heart J. 2001; 141: 992–998.CrossrefMedlineGoogle Scholar
    • 16 Devereux RB, Roman MJ, Paranicas M, O’Grady MJ, Lee ET, Welty TK, Fabsitz RR, Robbins D, Rhoades ER, Howard BV. Impact of diabetes on cardiac structure and function: the Strong Heart Study. Circulation. 2000; 101: 2271–2276.CrossrefMedlineGoogle Scholar
    • 17 Galderisi M, Anderson KM, Wilson PW, Levy D. Echocardiographic evidence for the existence of a distinct diabetic cardiomyopathy (the Framingham Heart Study). Am J Cardiol. 1991; 68: 85–89.CrossrefMedlineGoogle Scholar
    • 18 Struthers AD, Morris AD. Screening for and treating left-ventricular abnormalities in diabetes mellitus: a new way of reducing cardiac deaths. Lancet. 2002; 359: 1430–1432.CrossrefMedlineGoogle Scholar
    • 19 Liu JE, Palmieri V, Roman MJ, Bella JN, Fabsitz R, Howard BV, Welty TK, Lee ET, Devereux RB. The impact of diabetes on left ventricular filling pattern in normotensive and hypertensive adults: the Strong Heart Study. J Am Coll Cardiol. 2001; 37: 1943–1949.CrossrefMedlineGoogle Scholar
    • 20 Bell DS. Diabetic cardiomyopathy. Diabetes Care. 2003; 26: 2949–2951.CrossrefMedlineGoogle Scholar
    • 21 Schannwell CM, Schneppenheim M, Perings S, Plehn G, Strauer BE. Left ventricular diastolic dysfunction as an early manifestation of diabetic cardiomyopathy. Cardiology. 2002; 98: 33–39.CrossrefMedlineGoogle Scholar
    • 22 Carugo S, Giannattasio C, Calchera I, Paleari F, Gorgoglione MG, Grappiolo A, Gamba P, Rovaris G, Failla M, Mancia G. Progression of functional and structural cardiac alterations in young normotensive uncomplicated patients with type 1 diabetes mellitus. J Hypertens. 2001; 19: 1675–1680.CrossrefMedlineGoogle Scholar
    • 23 Di Bonito P, Cuomo S, Moio N, Sibilio G, Sabatini D, Quattrin S, Capaldo B. Diastolic dysfunction in patients with non-insulin-dependent diabetes mellitus of short duration. Diabet Med. 1996; 13: 321–324.CrossrefMedlineGoogle Scholar
    • 24 Beljic T, Miric M. Improved metabolic control does not reverse left ventricular filling abnormalities in newly diagnosed non-insulin-dependent diabetes patients. Acta Diabetol. 1994; 31: 147–150.CrossrefMedlineGoogle Scholar
    • 25 Nicolino A, Longobardi G, Furgi G, Rossi M, Zoccolillo N, Ferrara N, Rengo F. Left ventricular diastolic filling in diabetes mellitus with and without hypertension. Am J Hypertens. 1995; 8: 382–389.CrossrefMedlineGoogle Scholar
    • 26 Redfield MM, Jacobsen SJ, Burnett JC Jr, Mahoney DW, Bailey KR, Rodeheffer RJ. Burden of systolic and diastolic ventricular dysfunction in the community: appreciating the scope of the heart failure epidemic. JAMA. 2003; 289: 194–202.CrossrefMedlineGoogle Scholar
    • 27 Poirier P, Bogaty P, Garneau C, Marois L, Dumesnil JG. Diastolic dysfunction in normotensive men with well-controlled type 2 diabetes: importance of maneuvers in echocardiographic screening for preclinical diabetic cardiomyopathy. Diabetes Care. 2001; 24: 5–10.CrossrefMedlineGoogle Scholar
    • 28 Shivalkar B, Dhondt D, Goovaerts I, Van Gaal L, Bartunek J, Van Crombrugge P, Vrints C. Flow mediated dilatation and cardiac function in type 1 diabetes mellitus. Am J Cardiol. 2006; 97: 77–82.CrossrefMedlineGoogle Scholar
    • 29 Di Bonito P, Moio N, Cavuto L, Covino G, Murena E, Scilla C, Turco S, Capaldo B, Sibilio G. Early detection of diabetic cardiomyopathy: usefulness of tissue Doppler imaging. Diabet Med. 2005; 22: 1720–1725.CrossrefMedlineGoogle Scholar
    • 30 Aasum E, Belke DD, Severson DL, Riemersma RA, Cooper M, Andreassen M, Larsen TS. Cardiac function and metabolism in type 2 diabetic mice after treatment with BM 17.0744, a novel PPAR-alpha activator. Am J Physiol Heart Circ Physiol. 2002; 283: H949–H957.CrossrefMedlineGoogle Scholar
    • 31 Aasum E, Hafstad AD, Severson DL, Larsen TS. Age-dependent changes in metabolism, contractile function, and ischemic sensitivity in hearts from db/db mice. Diabetes. 2003; 52: 434–441.CrossrefMedlineGoogle Scholar
    • 32 Barouch LA, Berkowitz DE, Harrison RW, O’Donnell CP, Hare JM. Disruption of leptin signaling contributes to cardiac hypertrophy independently of body weight in mice. Circulation. 2003; 108: 754–759.LinkGoogle Scholar
    • 33 Boudina S, Sena S, O’Neill BT, Tathireddy P, Young ME, Abel ED. Reduced mitochondrial oxidative capacity and increased mitochondrial uncoupling impair myocardial energetics in obesity. Circulation. 2005; 112: 2686–2695.LinkGoogle Scholar
    • 34 Broderick TL, Poirier P. Cardiac function and ischaemic tolerance during acute loss of metabolic control in the diabetic BB Wor rat. Acta Diabetol. 2005; 42: 171–178.CrossrefMedlineGoogle Scholar
    • 35 Buchanan J, Mazumder PK, Hu P, Chakrabarti G, Roberts MW, Yun UJ, Cooksey RC, Litwin SE, Abel ED. Reduced cardiac efficiency and altered substrate metabolism precedes the onset of hyperglycemia and contractile dysfunction in two mouse models of insulin resistance and obesity. Endocrinology. 2005; 146: 5341–5349.CrossrefMedlineGoogle Scholar
    • 36 Christoffersen C, Bollano E, Lindegaard ML, Bartels ED, Goetze JP, Andersen CB, Nielsen LB. Cardiac lipid accumulation associated with diastolic dysfunction in obese mice. Endocrinology. 2003; 144: 3483–3490.CrossrefMedlineGoogle Scholar
    • 37 Conti M, Renaud IM, Poirier B, Michel O, Belair MF, Mandet C, Bruneval P, Myara I, Chevalier J. High levels of myocardial antioxidant defense in aging nondiabetic normotensive Zucker obese rats. Am J Physiol Regul Integr Comp Physiol. 2004; 286: R793–R800.CrossrefMedlineGoogle Scholar
    • 38 Desrois M, Sidell RJ, Gauguier D, Davey CL, Radda GK, Clarke K. Gender differences in hypertrophy, insulin resistance and ischemic injury in the aging type 2 diabetic rat heart. J Mol Cell Cardiol. 2004; 37: 547–555.CrossrefMedlineGoogle Scholar
    • 39 Fein FS, Miller-Green B, Sonnenblick EH. Altered myocardial mechanics in diabetic rabbits. Am J Physiol Heart Circ Physiol. 1985; 248: H729–H736.CrossrefMedlineGoogle Scholar
    • 40 Greer JJ, Ware DP, Lefer DJ. Myocardial infarction and heart failure in the db/db diabetic mouse. Am J Physiol Heart Circ Physiol. 2006; 290: H146–H153.CrossrefMedlineGoogle Scholar
    • 41 Hadour G, Ferrera R, Sebbag L, Forrat R, Delaye J, de Lorgeril M. Improved myocardial tolerance to ischaemia in the diabetic rabbit. J Mol Cell Cardiol. 1998; 30: 1869–1875.CrossrefMedlineGoogle Scholar
    • 42 Hoshida S, Yamashita N, Otsu K, Kuzuya T, Hori M. Cholesterol feeding exacerbates myocardial injury in Zucker diabetic fatty rats. Am J Physiol Heart Circ Physiol. 2000; 278: H256–H262.CrossrefMedlineGoogle Scholar
    • 43 Joffe II, Travers KE, Perreault-Micale CL, Hampton T, Katz SE, Morgan JP, Douglas PS. Abnormal cardiac function in the streptozotocin-induced non-insulin-dependent diabetic rat: noninvasive assessment with Doppler echocardiography and contribution of the nitric oxide pathway. J Am Coll Cardiol. 1999; 34: 2111–2119.CrossrefMedlineGoogle Scholar
    • 44 Jones SP, Girod WG, Granger DN, Palazzo AJ, Lefer DJ. Reperfusion injury is not affected by blockade of P-selectin in the diabetic mouse heart. Am J Physiol Heart Circ Physiol. 1999; 277: H763–H769.CrossrefMedlineGoogle Scholar
    • 45 Kajstura J, Fiordaliso F, Andreoli AM, Li B, Chimenti S, Medow MS, Limana F, Nadal-Ginard B, Leri A, Anversa P. IGF-1 overexpression inhibits the development of diabetic cardiomyopathy and angiotensin II-mediated oxidative stress. Diabetes. 2001; 50: 1414–1424.CrossrefMedlineGoogle Scholar
    • 46 Kralik PM, Ye G, Metreveli NS, Shem X, Epstein PN. Cardiomyocyte dysfunction in models of type 1 and type 2 diabetes. Cardiovasc Toxicol. 2005; 5: 285–292.CrossrefMedlineGoogle Scholar
    • 47 Kristiansen SB, Lofgren B, Stottrup NB, Khatir D, Nielsen-Kudsk JE, Nielsen TT, Botker HE, Flyvbjerg A. Ischaemic preconditioning does not protect the heart in obese and lean animal models of type 2 diabetes. Diabetologia. 2004; 47: 1716–1721.CrossrefMedlineGoogle Scholar
    • 48 Mazumder PK, O’Neill BT, Roberts MW, Buchanan J, Yun UJ, Cooksey RC, Boudina S, Abel ED. Impaired cardiac efficiency and increased fatty acid oxidation in insulin-resistant ob/ob mouse hearts. Diabetes. 2004; 53: 2366–2374.CrossrefMedlineGoogle Scholar
    • 49 Nielsen LB, Bartels ED, Bollano E. Overexpression of apolipoprotein B in the heart impedes cardiac triglyceride accumulation and development of cardiac dysfunction in diabetic mice. J Biol Chem. 2002; 277: 27014–27020.CrossrefMedlineGoogle Scholar
    • 50 Pacher P, Liaudet L, Soriano FG, Mabley JG, Szabo E, Szabo C. The role of poly(ADP-ribose) polymerase activation in the development of myocardial and endothelial dysfunction in diabetes. Diabetes. 2002; 51: 514–521.CrossrefMedlineGoogle Scholar
    • 51 Paradise NF, Pilati CF, Payne WR, Finkelstein JA. Left ventricular function of the isolated, genetically obese rat’s heart. Am J Physiol Heart Circ Physiol. 1985; 248: H438–H444.CrossrefMedlineGoogle Scholar
    • 52 Rodrigues B, McNeill JH. Cardiac dysfunction in isolated perfused hearts from spontaneously diabetic BB rats. Can J Physiol Pharmacol. 1990; 68: 514–518.CrossrefMedlineGoogle Scholar
    • 53 Semeniuk LM, Kryski AJ, Severson DL. Echocardiographic assessment of cardiac function in diabetic db/db and transgenic db/db-hGLUT4 mice. Am J Physiol Heart Circ Physiol. 2002; 283: H976–H982.CrossrefMedlineGoogle Scholar
    • 54 Shiomi T, Tsutsui H, Ikeuchi M, Matsusaka H, Hayashidani S, Suematsu N, Wen J, Kubota T, Takeshita A. Streptozotocin-induced hyperglycemia exacerbates left ventricular remodeling and failure after experimental myocardial infarction. J Am Coll Cardiol. 2003; 42: 165–172.CrossrefMedlineGoogle Scholar
    • 55 Trost SU, Belke DD, Bluhm WF, Meyer M, Swanson E, Dillmann WH. Overexpression of the sarcoplasmic reticulum Ca(2+)-ATPase improves myocardial contractility in diabetic cardiomyopathy. Diabetes. 2002; 51: 1166–1171.CrossrefMedlineGoogle Scholar
    • 56 Wang P, Chatham JC. Onset of diabetes in Zucker diabetic fatty (ZDF) rats leads to improved recovery of function after ischemia in the isolated perfused heart. Am J Physiol Endocrinol Metab. 2004; 286: E725–E736.CrossrefMedlineGoogle Scholar
    • 57 Zola BE, Miller B, Stiles GL, Rao PS, Sonnenblick EH, Fein FS. Heart rate control in diabetic rabbits: blunted response to isoproterenol. Am J Physiol Heart Endocrinol Metab. 1988; 255: E636–E641.CrossrefMedlineGoogle Scholar
    • 58 Broderick TL, Hutchison AK. Cardiac dysfunction in the euglycemic diabetic-prone BB Wor rat. Metabolism. 2004; 53: 1391–1394.CrossrefMedlineGoogle Scholar
    • 59 Belke DD, Larsen TS, Gibbs EM, Severson DL. Altered metabolism causes cardiac dysfunction in perfused hearts from diabetic (db/db) mice. Am J Physiol Endocrinol Metab. 2000; 279: E1104–E1113.CrossrefMedlineGoogle Scholar
    • 60 Marfella R, Di Filippo C, Esposito K, Nappo F, Piegari E, Cuzzocrea S, Berrino L, Rossi F, Giugliano D, D’Amico M. Absence of inducible nitric oxide synthase reduces myocardial damage during ischemia reperfusion in streptozotocin-induced hyperglycemic mice. Diabetes. 2004; 53: 454–462.CrossrefMedlineGoogle Scholar
    • 61 Young ME, Guthrie PH, Razeghi P, Leighton B, Abbasi S, Patil S, Youker KA, Taegtmeyer H. Impaired long-chain fatty acid oxidation and contractile dysfunction in the obese Zucker rat heart. Diabetes. 2002; 51: 2587–2595.CrossrefMedlineGoogle Scholar
    • 62 Severson DL. Diabetic cardiomyopathy: recent evidence from mouse models of type 1 and type 2 diabetes. Can J Physiol Pharmacol. 2004; 82: 813–823.CrossrefMedlineGoogle Scholar
    • 63 Golfman LS, Wilson CR, Sharma S, Burgmaier M, Young ME, Guthrie PH, Van Arsdall M, Adrogue JV, Brown KK, Taegtmeyer H. Activation of PPARgamma enhances myocardial glucose oxidation and improves contractile function in isolated working hearts of ZDF rats. Am J Physiol Endocrinol Metab. 2005; 289: E328–E336.CrossrefMedlineGoogle Scholar
    • 64 Carley AN, Semeniuk LM, Shimoni Y, Aasum E, Larsen TS, Berger JP, Severson DL. Treatment of type 2 diabetic db/db mice with a novel PPARgamma agonist improves cardiac metabolism but not contractile function. Am J Physiol Endocrinol Metab. 2004; 286: E449–E455.CrossrefMedlineGoogle Scholar
    • 65 Aasum E, Cooper M, Severson DL, Larsen TS. Effect of BM 17.0744, a PPARalpha ligand, on the metabolism of perfused hearts from control and diabetic mice. Can J Physiol Pharmacol. 2005; 83: 183–190.CrossrefMedlineGoogle Scholar
    • 66 Sidell RJ, Cole MA, Draper NJ, Desrois M, Buckingham RE, Clarke K. Thiazolidinedione treatment normalizes insulin resistance and ischemic injury in the Zucker fatty rat heart. Diabetes. 2002; 51: 1110–1117.CrossrefMedlineGoogle Scholar
    • 67 Wang P, Lloyd SG, Zeng H, Bonen A, Chatham JC. Impact of altered substrate utilization on cardiac function in isolated hearts from Zucker diabetic fatty rats. Am J Physiol Heart Circ Physiol. 2005; 288: H2102–H2110.CrossrefMedlineGoogle Scholar
    • 68 Rosen P, Herberg L, Reinauer H. Different types of postinsulin receptor defects contribute to insulin resistance in hearts of obese Zucker rats. Endocrinology. 1986; 119: 1285–1291.CrossrefMedlineGoogle Scholar
    • 69 Zhou YT, Grayburn P, Karim A, Shimabukuro M, Higa M, Baetens D, Orci L, Unger RH. Lipotoxic heart disease in obese rats: implications for human obesity. Proc Natl Acad Sci U S A. 2000; 97: 1784–1789.CrossrefMedlineGoogle Scholar
    • 70 Van den Bergh A, Flameng W, Herijgers P. Type II diabetic mice exhibit contractile dysfunction but maintain cardiac output by favourable loading conditions. Eur J Heart Fail. 2006; 8: 777–783.CrossrefMedlineGoogle Scholar
    • 71 Feuvray D, Lopaschuk GD. Controversies on the sensitivity of the diabetic heart to ischemic injury: the sensitivity of the diabetic heart to ischemic injury is decreased. Cardiovasc Res. 1997; 34: 113–120.CrossrefMedlineGoogle Scholar
    • 72 Paulson DJ. The diabetic heart is more sensitive to ischemic injury. Cardiovasc Res. 1997; 34: 104–112.CrossrefMedlineGoogle Scholar
    • 73 Thakker GD, Frangogiannis NG, Bujak M, Zymek P, Gaubatz JW, Reddy AK, Taffet G, Michael LH, Entman ML, Ballantyne CM. Effects of diet-induced obesity on inflammation and remodeling after myocardial infarction. Am J Physiol Heart Circ Physiol. 2006; 291: H2504–H2514.CrossrefMedlineGoogle Scholar
    • 74 Thim T, Bentzon JF, Kristiansen SB, Simonsen U, Andersen HL, Wassermann K, Falk E. Size of myocardial infarction induced by ischaemia/reperfusion is unaltered in rats with metabolic syndrome. Clin Sci (Lond). 2006; 110: 665–671.CrossrefMedlineGoogle Scholar
    • 75 Yue TL, Bao W, Gu JL, Cui J, Tao L, Ma XL, Ohlstein EH, Jucker BM. Rosiglitazone treatment in Zucker diabetic fatty rats is associated with ameliorated cardiac insulin resistance and protection from ischemia/reperfusion-induced myocardial injury. Diabetes. 2005; 54: 554–562.CrossrefMedlineGoogle Scholar
    • 76 Johns DG, Ao Z, Eybye M, Olzinski A, Costell M, Gruver S, Smith SA, Douglas SA, Macphee CH. Rosiglitazone protects against ischemia/reperfusion-induced leukocyte adhesion in the Zucker diabetic fatty rat. J Pharmacol Exp Ther. 2005; 315: 1020–1027.CrossrefMedlineGoogle Scholar
    • 77 Cittadini A, Mantzoros CS, Hampton TG, Travers KE, Katz SE, Morgan JP, Flier JS, Douglas PS. Cardiovascular abnormalities in transgenic mice with reduced brown fat: an animal model of human obesity. Circulation. 1999; 100: 2177–2183.CrossrefMedlineGoogle Scholar
    • 78 Spector KS. Diabetic cardiomyopathy. Clin Cardiol. 1998; 21: 885–887.CrossrefMedlineGoogle Scholar
    • 79 Tziakas DN, Chalikias GK, Kaski JC. Epidemiology of the diabetic heart. Coron Artery Dis. 2005; 16 (suppl 1): S3–S10.CrossrefMedlineGoogle Scholar
    • 80 Avendano GF, Agarwal RK, Bashey RI, Lyons MM, Soni BJ, Jyothirmayi GN, Regan TJ. Effects of glucose intolerance on myocardial function and collagen-linked glycation. Diabetes. 1999; 48: 1443–1447.CrossrefMedlineGoogle Scholar
    • 81 Capasso JM, Robinson TF, Anversa P. Alterations in collagen cross-linking impair myocardial contractility in the mouse heart. Circ Res. 1989; 65: 1657–1664.CrossrefMedlineGoogle Scholar
    • 82 Berg TJ, Snorgaard O, Faber J, Torjesen PA, Hildebrandt P, Mehlsen J, Hanssen KF. Serum levels of advanced glycation end products are associated with left ventricular diastolic function in patients with type 1 diabetes. Diabetes Care. 1999; 22: 1186–1190.CrossrefMedlineGoogle Scholar
    • 83 Endoh M. Signal transduction and Ca2+ signaling in intact myocardium. J Pharmacol Sci. 2006; 100: 525–537.CrossrefMedlineGoogle Scholar
    • 84 Cesario DA, Brar R, Shivkumar K. Alterations in ion channel physiology in diabetic cardiomyopathy. Endocrinol Metab Clin North Am. 2006; 35: 601–610, ix-x.CrossrefMedlineGoogle Scholar
    • 85 Zhao XY, Hu SJ, Li J, Mou Y, Chen BP, Xia Q. Decreased cardiac sarcoplasmic reticulum Ca2+ -ATPase activity contributes to cardiac dysfunction in streptozotocin-induced diabetic rats. J Physiol Biochem. 2006; 62: 1–8.CrossrefMedlineGoogle Scholar
    • 86 Lopaschuk GD, Tahiliani AG, Vadlamudi RV, Katz S, McNeill JH. Cardiac sarcoplasmic reticulum function in insulin- or carnitine-treated diabetic rats. Am J Physiol Heart Circ Physiol. 1983; 245: H969–H976.CrossrefMedlineGoogle Scholar
    • 87 Pierce GN, Dhalla NS. Cardiac myofibrillar ATPase activity in diabetic rats. J Mol Cell Cardiol. 1981; 13: 1063–1069.CrossrefMedlineGoogle Scholar
    • 88 Choi KM, Zhong Y, Hoit BD, Grupp IL, Hahn H, Dilly KW, Guatimosim S, Lederer WJ, Matlib MA. Defective intracellular Ca(2+) signaling contributes to cardiomyopathy in type 1 diabetic rats. Am J Physiol Heart Circ Physiol. 2002; 283: H1398–H1408.CrossrefMedlineGoogle Scholar
    • 89 Pereira L, Matthes J, Schuster I, Valdivia HH, Herzig S, Richard S, Gomez AM. Mechanisms of [Ca2+]i transient decrease in cardiomyopathy of db/db type 2 diabetic mice. Diabetes. 2006; 55: 608–615.CrossrefMedlineGoogle Scholar
    • 90 Hattori Y, Matsuda N, Kimura J, Ishitani T, Tamada A, Gando S, Kemmotsu O, Kanno M. Diminished function and expression of the cardiac Na+-Ca2+ exchanger in diabetic rats: implication in Ca2+ overload. J Physiol. 2000; 527: 85–94.CrossrefMedlineGoogle Scholar
    • 91 Kashihara H, Shi ZQ, Yu JZ, McNeill JH, Tibbits GF. Effects of diabetes and hypertension on myocardial Na+-Ca2+ exchange. Can J Physiol Pharmacol. 2000; 78: 12–19.CrossrefMedlineGoogle Scholar
    • 92 Belke DD, Swanson EA, Dillmann WH. Decreased sarcoplasmic reticulum activity and contractility in diabetic db/db mouse heart. Diabetes. 2004; 53: 3201–3208.CrossrefMedlineGoogle Scholar
    • 93 Barrans JD, Allen PD, Stamatiou D, Dzau VJ, Liew CC. Global gene expression profiling of end-stage dilated cardiomyopathy using a human cardiovascular-based cDNA microarray. Am J Pathol. 2002; 160: 2035–2043.CrossrefMedlineGoogle Scholar
    • 94 Piper C, Bilger J, Henrichs EM, Schultheiss HP, Horstkotte D, Doerner A. Is myocardial Na+/Ca2+ exchanger transcription a marker for different stages of myocardial dysfunction? Quantitative polymerase chain reaction of the messenger RNA in endomyocardial biopsies of patients with heart failure. J Am Coll Cardiol. 2000; 36: 233–241.CrossrefMedlineGoogle Scholar
    • 95 Sen L, Cui G, Fonarow GC, Laks H. Differences in mechanisms of SR dysfunction in ischemic vs. idiopathic dilated cardiomyopathy. Am J Physiol Heart Circ Physiol. 2000; 279: H709–H718.CrossrefMedlineGoogle Scholar
    • 96 Jweied EE, McKinney RD, Walker LA, Brodsky I, Geha AS, Massad MG, Buttrick PM, de Tombe PP. Depressed cardiac myofilament function in human diabetes mellitus. Am J Physiol Heart Circ Physiol. 2005; 289: H2478–H2483.CrossrefMedlineGoogle Scholar
    • 97 Fang ZY, Prins JB, Marwick TH. Diabetic cardiomyopathy: evidence, mechanisms, and therapeutic implications. Endocr Rev. 2004; 25: 543–567.CrossrefMedlineGoogle Scholar
    • 98 Dhalla NS, Liu X, Panagia V, Takeda N. Subcellular remodeling and heart dysfunction in chronic diabetes. Cardiovasc Res. 1998; 40: 239–247.CrossrefMedlineGoogle Scholar
    • 99 Fiordaliso F, Li B, Latini R, Sonnenblick EH, Anversa P, Leri A, Kajstura J. Myocyte death in streptozotocin-induced diabetes in rats in angiotensin II- dependent. Lab Invest J Tech Methods Pathol. 2000; 80: 513–527.CrossrefGoogle Scholar
    • 100 Khatter JC, Sadri P, Zhang M, Hoeschen RJ. Myocardial angiotensin II (Ang II) receptors in diabetic rats. Ann N York Acad Sci. 1996; 793: 466–472.CrossrefMedlineGoogle Scholar
    • 101 Christlieb AR, Long R, Underwood RH. Renin-angiotensin-aldosterone system, electrolyte homeostasis and blood pressure in alloxan diabetes. Am J Med Sci. 1979; 277: 295–303.CrossrefMedlineGoogle Scholar
    • 102 Frustaci A, Kajstura J, Chimenti C, Jakoniuk I, Leri A, Maseri A, Nadal-Ginard B, Anversa P. Myocardial cell death in human diabetes. Circ Res. 2000; 87: 1123–1132.CrossrefMedlineGoogle Scholar
    • 103 Liu X, Suzuki H, Sethi R, Tappia PS, Takeda N, Dhalla NS. Blockade of the renin-angiotensin system attenuates sarcolemma and sarcoplasmic reticulum remodeling in chronic diabetes. Ann N Y Acad Sci. 2006; 1084: 141–154.CrossrefMedlineGoogle Scholar
    • 104 Yaras N, Bilginoglu A, Vassort G, Turan B. Restoration of diabetes-induced abnormal local Ca2+ release in cardiomyocytes by angiotensin II receptor blockade. Am J Physiol Heart Circ Physiol. 2007; 292: H912–H920.CrossrefMedlineGoogle Scholar
    • 105 Fiordaliso F, Cuccovillo I, Bianchi R, Bai A, Doni M, Salio M, De Angelis N, Ghezzi P, Latini R, Masson S. Cardiovascular oxidative stress is reduced by an ACE inhibitor in a rat model of streptozotocin-induced diabetes. Life Sci. 2006; 79: 121–129.CrossrefMedlineGoogle Scholar
    • 106 Rosen R, Rump AF, Rosen P. The ACE-inhibitor captopril improves myocardial perfusion in spontaneously diabetic (BB) rats. Diabetologia. 1995; 38: 509–517.CrossrefMedlineGoogle Scholar
    • 107 Cai L, Wang Y, Zhou G, Chen T, Song Y, Li X, Kang YJ. Attenuation by metallothionein of early cardiac cell death via suppression of mitochondrial oxidative stress results in a prevention of diabetic cardiomyopathy. J Am Coll Cardiol. 2006; 48: 1688–1697.CrossrefMedlineGoogle Scholar
    • 108 Cai L. Suppression of nitrative damage by metallothionein in diabetic heart contributes to the prevention of cardiomyopathy. Free Radic Biol Med. 2006; 41: 851–861.CrossrefMedlineGoogle Scholar
    • 109 Wold LE, Ren J. Streptozotocin directly impairs cardiac contractile function in isolated ventricular myocytes via a p38 map kinase-dependent oxidative stress mechanism. Biochem Biophys Res Commun. 2004; 318: 1066–1071.CrossrefMedlineGoogle Scholar
    • 110 Cai L, Li W, Wang G, Guo L, Jiang Y, Kang YJ. Hyperglycemia-induced apoptosis in mouse myocardium: mitochondrial cytochrome C-mediated caspase-3 activation pathway. Diabetes. 2002; 51: 1938–1948.CrossrefMedlineGoogle Scholar
    • 111 Brownlee M. Advanced protein glycosylation in diabetes and aging. Annu Rev Med. 1995; 46: 223–234.CrossrefMedlineGoogle Scholar
    • 112 Shen X, Zheng S, Metreveli NS, Epstein PN. Protection of cardiac mitochondria by overexpression of MnSOD reduces diabetic cardiomyopathy. Diabetes. 2006; 55: 798–805.CrossrefMedlineGoogle Scholar
    • 113 Saraiva RM, Minhas KM, Zheng M, Pitz E, Treuer A, Gonzalez D, Schuleri KH, Vandegaer KM, Barouch LA, Hare JM. Reduced neuronal nitric oxide synthase expression contributes to cardiac oxidative stress and nitroso-redox imbalance in ob/ob mice. Nitric Oxide. 2006; 16: 331–338.MedlineGoogle Scholar
    • 114 Li SY, Yang X, Ceylan-Isik AF, Du M, Sreejayan N, Ren J. Cardiac contractile dysfunction in Lep/Lep obesity is accompanied by NADPH oxidase activation, oxidative modification of sarco(endo)plasmic reticulum Ca2+-ATPase and myosin heavy chain isozyme switch. Diabetologia. 2006; 49: 1434–1446.CrossrefMedlineGoogle Scholar
    • 115 Wohaieb SA, Godin DV. Alterations in free radical tissue-defense mechanisms in streptozocin-induced diabetes in rat: effects of insulin treatment. Diabetes. 1987; 36: 1014–1018.CrossrefMedlineGoogle Scholar
    • 116 Wohaieb SA, Godin DV. Alterations in tissue antioxidant systems in the spontaneously diabetic (BB Wistar) rat. Can J Physiol Pharmacol. 1987; 65: 2191–2195.CrossrefMedlineGoogle Scholar
    • 117 Volkovova K, Chorvathova V, Jurcovicova M, Koszeghyova L, Bobek P. Antioxidative state of the myocardium and kidneys in acute diabetic rats. Physiol Res. 1993; 42: 251–255.MedlineGoogle Scholar
    • 118 Kakkar R, Kalra J, Mantha SV, Prasad K. Lipid peroxidation and activity of antioxidant enzymes in diabetic rats. Mol Cell Biochem. 1995; 151: 113–119.CrossrefMedlineGoogle Scholar
    • 119 Turko IV, Murad F. Quantitative protein profiling in heart mitochondria from diabetic rats. J Biol Chem. 2003; 278: 35844–35849.CrossrefMedlineGoogle Scholar
    • 120 Matkovics B, Sasvari M, Kotorman M, Varga IS, Hai DQ, Varga C. Further prove on oxidative stress in alloxan diabetic rat tissues. Acta Physiologica Hungarica. 1997; 85: 183–192.MedlineGoogle Scholar
    • 121 Aliciguzel Y, Ozen I, Aslan M, Karayalcin U. Activities of xanthine oxidoreductase and antioxidant enzymes in different tissues of diabetic rats. J Lab Clin Med. 2003; 142: 172–177.CrossrefMedlineGoogle Scholar
    • 122 Kwon SH, Pimentel DR, Remondino A, Sawyer DB, Colucci WS. H(2)O(2) regulates cardiac myocyte phenotype via concentration-dependent activation of distinct kinase pathways. J Mol Cell Cardiol. 2003; 35: 615–621.CrossrefMedlineGoogle Scholar
    • 123 Koya D, King GL. Protein kinase C activation and the development of diabetic complications. Diabetes. 1998; 47: 859–866.CrossrefMedlineGoogle Scholar
    • 124 Liang Q, Carlson EC, Donthi RV, Kralik PM, Shen X, Epstein PN. Overexpression of metallothionein reduces diabetic cardiomyopathy. Diabetes. 2002; 51: 174–181.CrossrefMedlineGoogle Scholar
    • 125 Matsushima S, Kinugawa S, Ide T, Matsusaka H, Inoue N, Ohta Y, Yokota T, Sunagawa K, Tsutsui H. Overexpression of glutathione peroxidase attenuates myocardial remodeling and preserves diastolic function in diabetic heart. Am J Physiol Heart Circ Physiol. 2006; 291: H2237–H2245.CrossrefMedlineGoogle Scholar
    • 126 Ye G, Metreveli NS, Donthi RV, Xia S, Xu M, Carlson EC, Epstein PN. Catalase protects cardiomyocyte function in models of type 1 and type 2 diabetes. Diabetes. 2004; 53: 1336–1343.CrossrefMedlineGoogle Scholar
    • 127 Lopaschuk GD. Metabolic abnormalities in the diabetic heart. Heart Fail Rev. 2002; 7: 149–159.CrossrefMedlineGoogle Scholar
    • 128 Taegtmeyer H, McNulty P, Young ME. Adaptation and maladaptation of the heart in diabetes, part I: general concepts. Circulation. 2002; 105: 1727–1733.LinkGoogle Scholar
    • 129 Stanley WC, Lopaschuk GD, McCormack JG. Regulation of energy substrate metabolism in the diabetic heart. Cardiovasc Res. 1997; 34: 25–33.CrossrefMedlineGoogle Scholar
    • 130 Carley AN, Severson DL. Fatty acid metabolism is enhanced in type 2 diabetic hearts. Biochim Biophys Acta. 2005; 1734: 112–126.CrossrefMedlineGoogle Scholar
    • 131 McGavock JM, Victor RG, Unger RH, Szczepaniak LS. Adiposity of the heart, revisited. Ann Intern Med. 2006; 144: 517–524.CrossrefMedlineGoogle Scholar
    • 132 Sharma S, Adrogue JV, Golfman L, Uray I, Lemm J, Youker K, Noon GP, Frazier OH, Taegtmeyer H. Intramyocardial lipid accumulation in the failing human heart resembles the lipotoxic rat heart. FASEB J. 2004; 18: 1692–1700.CrossrefMedlineGoogle Scholar
    • 133 Szczepaniak LS, Dobbins RL, Metzger GJ, Sartoni-D’Ambrosia G, Arbique D, Vongpatanasin W, Unger R, Victor RG. Myocardial triglycerides and systolic function in humans: in vivo evaluation by localized proton spectroscopy and cardiac imaging. Magn Reson Med. 2003; 49: 417–423.CrossrefMedlineGoogle Scholar
    • 134 Finck BN, Lehman JJ, Leone TC, Welch MJ, Bennett MJ, Kovacs A, Han X, Gross RW, Kozak R, Lopaschuk GD, Kelly DP. The cardiac phenotype induced by PPARalpha overexpression mimics that caused by diabetes mellitus. J Clin Invest. 2002; 109: 121–130.CrossrefMedlineGoogle Scholar
    • 135 Finck BN, Han X, Courtois M, Aimond F, Nerbonne JM, Kovacs A, Gross RW, Kelly DP. A critical role for PPARalpha-mediated lipotoxicity in the pathogenesis of diabetic cardiomyopathy: modulation by dietary fat content. Proc Natl Acad Sci U S A. 2003; 100: 1226–1231.CrossrefMedlineGoogle Scholar
    • 136 Duncan JG, Fong JL, Medeiros DM, Finck BN, Kelly DP. Insulin-resistant heart exhibits a mitochondrial biogenic response driven by the peroxisome proliferator-activated receptor-alpha/PGC-1alpha gene regulatory pathway. Circulation. 2007; 115: 909–917.LinkGoogle Scholar
    • 137 Yang J, Sambandam N, Han X, Gross RW, Courtois M, Kovacs A, Febbraio M, Finck BN, Kelly DP. CD36 deficiency rescues lipotoxic cardiomyopathy. Circ Res. 2007; 100: 1208–1217.LinkGoogle Scholar
    • 138 Park SY, Cho YR, Kim HJ, Higashimori T, Danton C, Lee MK, Dey A, Rothermel B, Kim YB, Kalinowski A, Russell KS, Kim JK. Unraveling the temporal pattern of diet-induced insulin resistance in individual organs and cardiac dysfunction in C57BL/6 mice. Diabetes. 2005; 54: 3530–3540.CrossrefMedlineGoogle Scholar
    • 139 Belke DD, Betuing S, Tuttle MJ, Graveleau C, Young ME, Pham M, Zhang D, Cooksey RC, McClain DA, Litwin SE, Taegtmeyer H, Severson D, Kahn CR, Abel ED. Insulin signaling coordinately regulates cardiac size, metabolism, and contractile protein isoform expression. J Clin Invest. 2002; 109: 629–639.CrossrefMedlineGoogle Scholar
    • 140 Coort SL, Hasselbaink DM, Koonen DP, Willems J, Coumans WA, Chabowski A, van der Vusse GJ, Bonen A, Glatz JF, Luiken JJ. Enhanced sarcolemmal FAT/CD36 content and triacylglycerol storage in cardiac myocytes from obese Zucker rats. Diabetes. 2004; 53: 1655–1663.CrossrefMedlineGoogle Scholar
    • 141 Chatham JC, Gao ZP, Bonen A, Forder JR. Preferential inhibition of lactate oxidation relative to glucose oxidation in the rat heart following diabetes. Cardiovasc Res. 1999; 43: 96–106.CrossrefMedlineGoogle Scholar
    • 142 Chatham JC, Gao ZP, Forder JR. Impact of 1 wk of diabetes on the regulation of myocardial carbohydrate and fatty acid oxidation. Am J Physiol Endocrinol Metab. 1999; 277: E342–E351.CrossrefMedlineGoogle Scholar
    • 143 Oakes ND, Thalen P, Aasum E, Edgley A, Larsen T, Furler SM, Ljung B, Severson D. Cardiac metabolism in mice: tracer method developments and in vivo application revealing profound metabolic inflexibility in diabetes. Am J Physiol Endocrinol Metab. 2006; 290: E870–E881.CrossrefMedlineGoogle Scholar
    • 144 Lopaschuk GD, Lakey JR, Barr R, Wambolt R, Thomson AB, Clandinin MT, Rajotte RV. Islet transplantation improves glucose oxidation and mechanical function in diabetic rat hearts. Can J Physiol Pharmacol. 1993; 71: 896–903.CrossrefMedlineGoogle Scholar
    • 145 Yokoyama M, Yagyu H, Hu Y, Seo T, Hirata K, Homma S, Goldberg IJ. Apolipoprotein B production reduces lipotoxic cardiomyopathy: studies in heart-specific lipoprotein lipase transgenic mouse. J Biol Chem. 2004; 279: 4204–4211.CrossrefMedlineGoogle Scholar
    • 146 Lee Y, Naseem RH, Duplomb L, Park BH, Garry DJ, Richardson JA, Schaffer JE, Unger RH. Hyperleptinemia prevents lipotoxic cardiomyopathy in acyl CoA synthase transgenic mice. Proc Natl Acad Sci U S A. 2004; 101: 13624–13629.CrossrefMedlineGoogle Scholar
    • 147 Luptak I, Balschi JA, Xing Y, Leone TC, Kelly DP, Tian R. Decreased contractile and metabolic reserve in peroxisome proliferator–activated receptor-alpha–null hearts can be rescued by increasing glucose transport and utilization. Circulation. 2005; 112: 2339–2346.LinkGoogle Scholar
    • 148 How OJ, Aasum E, Severson DL, Chan WY, Essop MF, Larsen TS. Increased myocardial oxygen consumption reduces cardiac efficiency in diabetic mice. Diabetes. 2006; 55: 466–473.CrossrefMedlineGoogle Scholar
    • 149 Dragoy Hafstad A, Khalid AM, How OJ, Larsen TS, Aasum E. Glucose and insulin improve cardiac efficiency and post-ischemic functional recovery in perfused hearts from type 2 diabetic (db/db) mice. Am J Physiol Endocrinol Metab. 2007; 292: E1288–E1294.CrossrefMedlineGoogle Scholar
    • 150 Durgan DJ, Smith JK, Hotze MA, Egbejimi O, Cuthbert KD, Zaha VG, Dyck JR, Abel ED, Young ME. Distinct transcriptional regulation of long-chain acyl-CoA synthetase isoforms and cytosolic thioesterase 1 in the rodent heart by fatty acids and insulin. Am J Physiol Heart Circ Physiol. 2006; 290: H2480–H2497.CrossrefMedlineGoogle Scholar
    • 151 Stavinoha MA, RaySpellicy JW, Essop MF, Graveleau C, Abel ED, Hart-Sailors ML, Mersmann HJ, Bray MS, Young ME. Evidence for mitochondrial thioesterase 1 as a peroxisome proliferator-activated receptor-alpha-regulated gene in cardiac and skeletal muscle. Am J Physiol Endocrinol Metab. 2004; 287: E888–E895.CrossrefMedlineGoogle Scholar
    • 152 Murray AJ, Panagia M, Hauton D, Gibbons GF, Clarke K. Plasma free fatty acids and peroxisome proliferator-activated receptor alpha in the control of myocardial uncoupling protein levels. Diabetes. 2005; 54: 3496–3502.CrossrefMedlineGoogle Scholar
    • 153 Boudina S, Abel ED. Mitochondrial uncoupling: a key contributor to reduced cardiac efficiency in diabetes. Physiology (Bethesda). 2006; 21: 250–258.CrossrefMedlineGoogle Scholar
    • 154 Herrero P, Peterson LR, McGill JB, Matthew S, Lesniak D, Dence C, Gropler RJ. Increased myocardial fatty acid metabolism in patients with type 1 diabetes mellitus. J Am Coll Cardiol. 2006; 47: 598–604.CrossrefMedlineGoogle Scholar
    • 155 Doria A, Nosadini R, Avogaro A, Fioretto P, Crepaldi G. Myocardial metabolism in type 1 diabetic patients without coronary artery disease. Diabet Med. 1991; 8: S104–S107.CrossrefMedlineGoogle Scholar
    • 156 Peterson LR, Herrero P, Schechtman KB, Racette SB, Waggoner AD, Kisrieva-Ware Z, Dence C, Klein S, Marsala J, Meyer T, Gropler RJ. Effect of obesity and insulin resistance on myocardial substrate metabolism and efficiency in young women. Circulation. 2004; 109: 2191–2196.LinkGoogle Scholar
    • 157 Lautamaki R, Airaksinen KE, Seppanen M, Toikka J, Luotolahti M, Ball E, Borra R, Harkonen R, Iozzo P, Stewart M, Knuuti J, Nuutila P. Rosiglitazone improves myocardial glucose uptake in patients with type 2 diabetes and coronary artery disease: a 16-week randomized, double-blind, placebo-controlled study. Diabetes. 2005; 54: 2787–2794.CrossrefMedlineGoogle Scholar
    • 158 Iozzo P, Chareonthaitawee P, Dutka D, Betteridge DJ, Ferrannini E, Camici PG. Independent association of type 2 diabetes and coronary artery disease with myocardial insulin resistance. Diabetes. 2002; 51: 3020–3024.CrossrefMedlineGoogle Scholar
    • 159 Nesto RW, Bell D, Bonow RO, Fonseca V, Grundy SM, Horton ES, Le Winter M, Porte D, Semenkovich CF, Smith S, Young LH, Kahn R. Thiazolidinedione use, fluid retention, and congestive heart failure: a consensus statement from the American Heart Association and American Diabetes Association. Diabetes Care. 2004; 27: 256–263.CrossrefMedlineGoogle Scholar
    • 160 Russell LK, Mansfield CM, Lehman JJ, Kovacs A, Courtois M, Saffitz JE, Medeiros DM, Valencik ML, McDonald JA, Kelly DP. Cardiac-specific induction of the transcriptional coactivator peroxisome proliferator-activated receptor gamma coactivator-1alpha promotes mitochondrial biogenesis and reversible cardiomyopathy in a developmental stage-dependent manner. Circ Res. 2004; 94: 525–533.LinkGoogle Scholar
    • 161 An D, Rodrigues B. Role of changes in cardiac metabolism in development of diabetic cardiomyopathy. Am J Physiol Heart Circ Physiol. 2006; 291: H1489–H1506.CrossrefMedlineGoogle Scholar
    • 162 Kuo TH, Moore KH, Giacomelli F, Wiener J. Defective oxidative metabolism of heart mitochondria from genetically diabetic mice. Diabetes. 1983; 32: 781–787.CrossrefMedlineGoogle Scholar
    • 163 Pierce GN, Dhalla NS. Heart mitochondrial function in chronic experimental diabetes in rats. Can J Cardiol. 1985; 1: 48–54.MedlineGoogle Scholar
    • 164 Tanaka Y, Konno N, Kako KJ. Mitochondrial dysfunction observed in situ in cardiomyocytes of rats in experimental diabetes. Cardiovasc Res. 1992; 26: 409–414.CrossrefMedlineGoogle Scholar
    • 165 Lashin O, Romani A. Hyperglycemia does not alter state 3 respiration in cardiac mitochondria from type-I diabetic rats. Mol Cell Biochem. 2004; 267: 31–37.CrossrefMedlineGoogle Scholar
    • 166 Shen X, Zheng S, Thongboonkerd V, Xu M, Pierce WM Jr, Klein JB, Epstein PN. Cardiac mitochondrial damage and biogenesis in a chronic model of type 1 diabetes. Am J Physiol Endocrinol Metab. 2004; 287: E896–E905.CrossrefMedlineGoogle Scholar
    • 167 Savabi F. Mitochondrial creatine phosphokinase deficiency in diabetic rat heart. Biochem Biophys Res Commun. 1988; 154: 469–475.CrossrefMedlineGoogle Scholar
    • 168 Awaji Y, Hashimoto H, Matsui Y, Kawaguchi K, Okumura K, Ito T, Satake T. Isoenzyme profiles of creatine kinase, lactate dehydrogenase, and aspartate aminotransferase in the diabetic heart: comparison with hereditary and catecholamine cardiomyopathies. Cardiovasc Res. 1990; 24: 547–554.CrossrefMedlineGoogle Scholar
    • 169 Veksler VI, Murat I, Ventura-Clapier R. Creatine kinase and mechanical and mitochondrial functions in hereditary and diabetic cardiomyopathies. Can J Physiol Pharmacol. 1991; 69: 852–858.CrossrefMedlineGoogle Scholar
    • 170 Oliveira PJ, Seica R, Coxito PM, Rolo AP, Palmeira CM, Santos MS, Moreno AJ. Enhanced permeability transition explains the reduced calcium uptake in cardiac mitochondria from streptozotocin-induced diabetic rats. FEBS Lett. 2003; 554: 511–514.CrossrefMedlineGoogle Scholar
    • 171 Nishio Y, Kanazawa A, Nagai Y, Inagaki H, Kashiwagi A. Regulation and role of the mitochondrial transcription factor in the diabetic rat heart. Ann N Y Acad Sci. 2004; 1011: 78–85.CrossrefMedlineGoogle Scholar
    • 172 Kanazawa A, Nishio Y, Kashiwagi A, Inagaki H, Kikkawa R, Horiike K. Reduced activity of mtTFA decreases the transcription in mitochondria isolated from diabetic rat heart. Am J Physiol Endocrinol Metab. 2002; 282: E778–E785.CrossrefMedlineGoogle Scholar
    • 173 Turko IV, Li L, Aulak KS, Stuehr DJ, Chang JY, Murad F. Protein tyrosine nitration in the mitochondria from diabetic mouse heart: implications to dysfunctional mitochondria in diabetes. J Biol Chem. 2003; 278: 33972–33977.CrossrefMedlineGoogle Scholar
    • 174 Ghosh S, Pulinilkunnil T, Yuen G, Kewalramani G, An D, Qi D, Abrahani A, Rodrigues B. Cardiomyocyte apoptosis induced by short-term diabetes requires mitochondrial GSH depletion. Am J Physiol Heart Circ Physiol. 2005; 289: H768–H776.CrossrefMedlineGoogle Scholar
    • 175 Metzler B, Schocke MF, Steinboeck P, Wolf C, Judmaier W, Lechleitner M, Lukas P, Pachinger O. Decreased high-energy phosphate ratios in the myocardium of men with diabetes mellitus type I. J Cardiovasc Magn Reson. 2002; 4: 493–502.MedlineGoogle Scholar
    • 176 Scheuermann-Freestone M, Madsen PL, Manners D, Blamire AM, Buckingham RE, Styles P, Radda GK, Neubauer S, Clarke K. Abnormal cardiac and skeletal muscle energy metabolism in patients with type 2 diabetes. Circulation. 2003; 107: 3040–3046.LinkGoogle Scholar
    • 177 Leone TC, Lehman JJ, Finck BN, Schaeffer PJ, Wende AR, Boudina S, Courtois M, Wozniak DF, Sambandam N, Bernal-Mizrachi C, Chen Z, Holloszy JO, Medeiros DM, Schmidt RE, Saffitz JE, Abel ED, Semenkovich CF, Kelly DP. PGC-1alpha deficiency causes multi-system energy metabolic derangements: muscle dysfunction, abnormal weight control and hepatic steatosis. PLoS Biol. 2005; 3: e101.CrossrefMedlineGoogle Scholar
    • 178 Lin J, Wu PH, Tarr PT, Lindenberg KS, St-Pierre J, Zhang CY, Mootha VK, Jager S, Vianna CR, Reznick RM, Cui L, Manieri M, Donovan MX, Wu Z, Cooper MP, Fan MC, Rohas LM, Zavacki AM, Cinti S, Shulman GI, Lowell BB, Krainc D, Spiegelman BM. Defects in adaptive energy metabolism with CNS-linked hyperactivity in PGC-1alpha null mice. Cell. 2004; 119: 121–135.CrossrefMedlineGoogle Scholar
    • 179 Lehman JJ, Barger PM, Kovacs A, Saffitz JE, Medeiros DM, Kelly DP. Peroxisome proliferator-activated receptor gamma coactivator-1 promotes cardiac mitochondrial biogenesis. J Clin Invest. 2000; 106: 847–856.CrossrefMedlineGoogle Scholar
    • 180 Graham BH, Waymire KG, Cottrell B, Trounce IA, MacGregor GR, Wallace DC. A mouse model for mitochondrial myopathy and cardiomyopathy resulting from a deficiency in the heart/muscle isoform of the adenine nucleotide translocator. Nat Genet. 1997; 16: 226–234.CrossrefMedlineGoogle Scholar
    • 181 Li H, Wang J, Wilhelmsson H, Hansson A, Thoren P, Duffy J, Rustin P, Larsson NG. Genetic modification of survival in tissue-specific knockout mice with mitochondrial cardiomyopathy. Proc Natl Acad Sci U S A. 2000; 97: 3467–3472.CrossrefMedlineGoogle Scholar

    eLetters(0)

    eLetters should relate to an article recently published in the journal and are not a forum for providing unpublished data. Comments are reviewed for appropriate use of tone and language. Comments are not peer-reviewed. Acceptable comments are posted to the journal website only. Comments are not published in an issue and are not indexed in PubMed. Comments should be no longer than 500 words and will only be posted online. References are limited to 10. Authors of the article cited in the comment will be invited to reply, as appropriate.

    Comments and feedback on AHA/ASA Scientific Statements and Guidelines should be directed to the AHA/ASA Manuscript Oversight Committee via its Correspondence page.