This study investigates the mechanism of cardiac dilatation and reduced contractility in obese Zucker Diabetic Fatty (ZDF) rats, focusing on the role of lipotoxicity and lipoapoptosis. The researchers found that myocardial triacylglycerol (TG) levels were elevated due to the underexpression of fatty acid oxidative enzymes and their transcription factor, peroxisome proliferator-activated receptor-α. Levels of ceramide, a mediator of apoptosis, were significantly higher, and inducible nitric oxide synthase levels were also elevated. Myocardial DNA laddering, an index of apoptosis, was 20 times higher than normal. Troglitazone therapy reduced myocardial TG and ceramide levels and completely prevented DNA laddering and loss of cardiac function, suggesting that cardiac dysfunction in obesity is caused by lipoapoptosis and can be prevented by reducing cardiac lipids. The study also highlights the implications of obesity-related heart disease, which is often attributed to coexisting disorders such as coronary artery disease and hypertension. However, the study suggests that cardiac dysfunction, arrhythmias, cardiomyopathy, and congestive heart failure may also be due to the direct consequences of obesity, specifically fatty acid overload of cardiac myocytes. The study used ZDF rats with a loss-of-function mutation in the leptin receptor to model obesity and found evidence of lipoapoptosis in their fat-laden hearts, accompanied by a profound loss of cardiac function. These abnormalities were completely prevented by antisteatotic therapy. The study found that the excessive deposition of TG in nonadipose tissues leads to an increase in intracellular fatty acyl-CoA, providing substrate for nonoxidative metabolic pathways such as ceramide synthesis, which leads to cell dysfunction and death through apoptosis. The study also found that the lipoapoptotic pathway in the heart involves an increase in de novo ceramide synthesis due to the overabundance of precursor long-chain FAs. The study suggests that the increased ceramide content and iNOS expression are associated with the progression of cardiac apoptosis. The study concludes that the cardiac dysfunction in obesity is caused by lipoapoptosis and can be prevented by reducing cardiac lipids. The findings suggest that the same metabolic abnormalities that cause lipotoxicity and lipoapoptosis in the pancreatic β cells of obese rats may also compromise the function and viability of their myocardial cells. The study also suggests that if a human counterpart of this cardiac lipotoxicity is identified, there are available agents that should be effective alone or in combination. The study highlights the importance of understanding the mechanisms of lipotoxicity and lipoapoptosis in obesity and the potential for antisteatotic therapy to prevent cardiac dysfunction.This study investigates the mechanism of cardiac dilatation and reduced contractility in obese Zucker Diabetic Fatty (ZDF) rats, focusing on the role of lipotoxicity and lipoapoptosis. The researchers found that myocardial triacylglycerol (TG) levels were elevated due to the underexpression of fatty acid oxidative enzymes and their transcription factor, peroxisome proliferator-activated receptor-α. Levels of ceramide, a mediator of apoptosis, were significantly higher, and inducible nitric oxide synthase levels were also elevated. Myocardial DNA laddering, an index of apoptosis, was 20 times higher than normal. Troglitazone therapy reduced myocardial TG and ceramide levels and completely prevented DNA laddering and loss of cardiac function, suggesting that cardiac dysfunction in obesity is caused by lipoapoptosis and can be prevented by reducing cardiac lipids. The study also highlights the implications of obesity-related heart disease, which is often attributed to coexisting disorders such as coronary artery disease and hypertension. However, the study suggests that cardiac dysfunction, arrhythmias, cardiomyopathy, and congestive heart failure may also be due to the direct consequences of obesity, specifically fatty acid overload of cardiac myocytes. The study used ZDF rats with a loss-of-function mutation in the leptin receptor to model obesity and found evidence of lipoapoptosis in their fat-laden hearts, accompanied by a profound loss of cardiac function. These abnormalities were completely prevented by antisteatotic therapy. The study found that the excessive deposition of TG in nonadipose tissues leads to an increase in intracellular fatty acyl-CoA, providing substrate for nonoxidative metabolic pathways such as ceramide synthesis, which leads to cell dysfunction and death through apoptosis. The study also found that the lipoapoptotic pathway in the heart involves an increase in de novo ceramide synthesis due to the overabundance of precursor long-chain FAs. The study suggests that the increased ceramide content and iNOS expression are associated with the progression of cardiac apoptosis. The study concludes that the cardiac dysfunction in obesity is caused by lipoapoptosis and can be prevented by reducing cardiac lipids. The findings suggest that the same metabolic abnormalities that cause lipotoxicity and lipoapoptosis in the pancreatic β cells of obese rats may also compromise the function and viability of their myocardial cells. The study also suggests that if a human counterpart of this cardiac lipotoxicity is identified, there are available agents that should be effective alone or in combination. The study highlights the importance of understanding the mechanisms of lipotoxicity and lipoapoptosis in obesity and the potential for antisteatotic therapy to prevent cardiac dysfunction.