Spillover of Fatty Acids During Dietary Fat Storage in Type 2 Diabetes: Relationship to Body Fat Depots and Effects of Weight Loss

摘要

Spillover of lipoprotein lipase-generated fatty acids from chylo-microns into the plasma free fatty acid (FFA) pool is an important source of FFA and reflects inefficiency in dietary fat storage. We measured spillover in 13 people with type 2 diabetes using infusions of a [3~H]triolein-labeled lipid emulsion and [U-(13)~C]oleate during continuous feeding, before and after weight loss. Body fat was measured with dual energy X-ray absorptiometry and computed tomography. Participants lost -14% of body weight. There was an ～38% decrease in meal-suppressed FFA concentration (P ＜ 0.0001) and an～ 23% decrease in oleate flux (P = 0.007). Fractional spillover did not change (P = NS). At baseline, there was a strong negative correlation between spillover and leg fat (r = -0.79, P = 0.001) and a positive correlation with the trunk-to-leg fat ratio (R = 0.56, P = 0.047). These correlations disappeared after weight loss. Baseline leg fat (R = -0.61, P = 0.027) but not trunk fat (R = -0.27, P = 0.38) negatively predicted decreases in spillover with weight loss. These results indicate that spillover, a measure of inefficiency in dietary fat storage, is inversely associated with lower body fat in type 2 diabetes.