Title

Lipotoxicity in Humans: Effects of a Very Low Calorie Diet and Starvation on Myocardial Triglyceride Content and Cardiac Function.

Authors

Hammer, Sebastiaan; Van Der Meer, Rutger W.; Lamb, Hildo J.; De Roos, Albert; Romijn, Johannes A.; Smit, Jan W.

Abstract

Ectopic accumulation of triglycerides (TG) in non-adipose tissues, including the heart, is involved in the pathogenesis of type 2 Diabetes Mellitus (DM) related heart disease in animal models. To determine in humans whether dietary induced changes in myocardial TG content influence left ventricular (LV) function, we measured myocardial TG content using proton Magnetic Resonance Spectroscopy (¹H-MRS) and LV function (Magnetic Resonance Imaging at 1.5T) in 10 healthy men (normal glucose tolerance, mean age SD: 24 5 yrs, BMI 24 3 kg/m²) at baseline, after a 3-day Very Low Calorie Diet (VLCD, 473 kcal/day) and after 3 days of starvation (0 kcal/day). The percentage of myocardial TG was calculated as TG/water x 100. Myocardial function was calculated as Ejection Fraction (EF) for systolic function, and bloodflow across the mitral valve in Early diastole and at Atrial contraction (E/A ratio) for diastolic function. Myocardial TG content increased from 0.35 0.14% at baseline to 0.59 0.27% after the VLCD and to 1.26 0.49% after starvation (P < 0.01). Myocardial E/A ratio decreased from 2.2 0.4 at baseline to 2.1 0.4 after the VLCD (P = 0.7) and to 1.8 0.4 after starvation (P < 0.01). Furthermore, Free Fatty Acids (FFA) increased from 0.59 0.36 mmol/L at baseline to 1.23 0.41 mmol/L after the VLCD and to 1.85 0.69 mmol/L after starvation (P = 0.000). LV EF was unchanged after the VLCD (59 4%) and after starvation (60 6%) as compared to baseline (59 4%, P > 0.1). These data show, that dietary induced changes in plasma FFA levels are paralleled by changes in myocardial TG content, associated with a decrease in myocardial diastolic function. Therefore, increased myocardial TG accumulation is not restricted to the pathophysiology of type 2 DM, but also reflects a physiological response to dietary interventions in healthy individuals.

Subjects

TRIGLYCERIDES; TYPE 2 diabetes; HEART diseases; MAGNETIC resonance imaging; STARVATION; FATTY acids; MITRAL valve; PATHOLOGICAL physiology

Publication

Diabetes, 2007, Vol 56, pA15

ISSN

0012-1797

Publication type

Academic Journal