Pancreatic Steatosis and Its Relationship to β-Cell Dysfunction in Humans

OBJECTIVE-To evaluate racial/ethnic differences in pancreatic triglyceride (TG) levels and their relationship to beta-cell dysfunction in humans. RESEARCH DESIGN AND METHODS-We studied black, Hispanic, and white adults who completed three research visits: screening and an oral glucose tolerance test; frequently sampled intravenous glucose tolerance tests for evaluation of beta-cell function and insulin resistance; and proton magnetic resonance spectroscopy for evaluation of pancreatic and hepatic TG levels. RESULTS-Pancreatic TG levels were higher in Hispanics and whites than in blacks (P = 0.006). Hepatic TG levels were highest in Hispanics (P = 0.004). Compensatory insulin secretion and disposition index were higher in blacks (P = 0.003 and P = 0.024, respectively). Insulin sensitivity was comparable between Hispanics and blacks and was lower than in whites (P = 0.005). In blacks, compensatory insulin secretion increased steeply with small increments in pancreatic TG levels (R-2 = 0.45, slope = 247). In whites, the range of pancreatic TG levels was higher, and the slope was less steep than in blacks (R-2 = 0.27, slope = 27). In Hispanics, pancreatic TG levels were similar to those of whites, but compensatory insulin secretion was described by a combination of pancreatic and hepatic TG levels and visceral fat mass (R-2 = 0.32). CONCLUSIONS-In a multiethnic sample of adults with mild obesity and without diabetes, we found striking ethnic differences in the levels of pancreatic TGs and in the relationship between pancreatic TGs and beta-cell dysfunction. Our data implicate pancreatic TG content measured by proton magnetic resonance spectroscopy as a noninvasive novel biomarker for pancreatic beta-cell dysfunction, especially in the Hispanic population. Diabetes Care 35:2377-2383, 2012