Ethnic differences in in vitro glyceride synthesis in subcutaneous and omental adipose tissue.

Considerable evidence suggests that there are ethnic differences in lipid metabolism between African American and Caucasian women, which may result in increased synthesis of fat in adipose tissue. The purpose of this study was to measure the in vitro rates of [14C]glucose incorporation into the glyceride-glycerol backbone of triglycerides (TG) and diglycerides (DG) in abdominal subcutaneous (SAT) and omental adipose tissue (OAT). Morbidly obese [African American (n = 15): body mass index (BMI) = 45 +/- 2.3; Caucasian (n = 18): BMI = 51 +/- 2.3] and preobese [African American (n = 7): BMI = 27 +/- 1.0; Caucasian (n = 7): BMI = 25 +/- 1.0] women were examined in this study. There were no significant differences in the rates of synthesis of either TG or DG in SAT of either preobese or obese women. On the other hand, both preobese and obese African American women had higher rates of synthesis of TG in OAT compared with their Caucasian counterparts. This increase in TG synthesis in OAT was not due to differences in cell size or rates of reesterification. Thus African American woman have an increased capacity to synthesize TG in OAT compared with Caucasian women, which may contribute to the higher prevalence of obesity in African American women.

Lipoprotein subpopulation distributions in lean, obese, and type 2 diabetic women: a comparison of African and white Americans.

OBJECTIVE: Abnormal subpopulation distributions of plasma lipoproteins have been reported in white American (WA) women with obesity and type 2 diabetes that explain part of the elevated rate of cardiovascular disease in these patients. This study examined if these perturbations also occur in obese and diabetic African American (AA) women and compared the lipoprotein profiles with WA counterparts. RESEARCH METHODS AND PROCEDURES: We determined the lipoprotein subpopulation distribution in the plasma of 51 lean women (29 WA, 22 AA, body mass index [BMI] < 30), 50 obese women (27 WA, 23 AA, BMI > 30), and 43 obese women with type 2 diabetes (27 WA, 16 AA), by nuclear magnetic resonance spectroscopy. RESULTS: AA diabetic women, like WA diabetic women, had a larger average very low density lipoprotein (VLDL) size, elevated levels of small low density lipoprotein cholesterol (LDL-C), and lower levels of small high density lipoprotein cholesterol (HDL-C), when compared to lean controls (p<0.05). These differences were accompanied by higher VLDL-triglycerides (TG) and LDL-C in WA (p<0.05), but not in AA. Although the effects of obesity and diabetes on lipoprotein subpopulation were fairly similar for AA and WA, some racial differences, particularly with respect to HDL, were observed. DISCUSSION: The atherogenic perturbations in lipoprotein profiles of obese AA women, particularly those with diabetes, were relatively similar to those found in WA women and may be contributing to the increased rate of cardiovascular disease (CVD) in AA with obesity and diabetes. The parameters of subpopulation distribution may provide better markers for CVD than lipid concentrations alone, particularly in AA women. Furthermore, subtle racial differences in lipoprotein profiles suggest that race-specific criteria may be needed to screen patients for CVD.