Hepatic triglycerides contribute to diabetic cardiomyopathy
MedWire News: Type 2 diabetes patients with high levels of triglycerides in their livers show signs of impaired myocardial metabolism, report researchers in the Journal of the American College of Cardiology.
Diabetic cardiomyopathy can develop in diabetic patients even in the absence of complications. It has a "high propensity to progress into overt congestive heart failure," say Michaela Diamant (University Medical Center, Amsterdam, The Netherlands) and colleagues.
The researchers' study included 61 Type 2 diabetes patients who did not have cardiovascular disease or other complications, which they say allowed the "assessment of early myocardial abnormalities in the absence of potentially confounding effects of coronary artery disease and hypertension."
The team divided the patients into those with high (median=14.4%) and low (median=2.0%) liver triglyceride content. Patients with high liver triglyceride content had significantly more hepatic visceral fat than those with low content, at 2.6 versus 2.4 ml, and more subcutaneous fat, at 743 versus 604 ml. They did not have significantly higher plasma triglyceride levels.
Patients with high liver triglycerides had significantly decreased whole-body insulin sensitivity compared with those with low triglycerides.
They also had reduced myocardial perfusion, with a mean blood flow of 1.07 versus 1.26 mg/g/mmHg/min/m in those with low liver triglycerides. In contrast, myocardial vascular resistance was increased in patients with high versus low liver triglycerides, at 118 versus 98 mmHg/ml/min/m.
Glucose uptake and the ratio of phosphocreatine to adenosine triphosphate were both significantly reduced in patients with high compared with low liver triglycerides.
Blood pressure and left ventricular systolic and diastolic function were not associated with patients' liver triglyceride content, however.
The myocardial changes observed in the current study, "may indicate an early alteration in myocardial tissue and/or vascular properties in Type 2 diabetes mellitus patients with high liver triglyceride content," say the researchers.
They conclude: "The long-term clinical implications of this association between liver steatosis and altered cardiac metabolism require further study in Type 2 diabetes mellitus."
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By Eleanor McDermid