Relationship between serum secreted Frizzled-related protein 4 and the pancreatic β cell function

Abstract

Objective To investigate the relationship between serum secreted frizzled-related protein 4(SFRP4) and the first-phase of glucose-stimulated insulin secretion from pancreatic β cell under different glucose tolerance statuses. Methods Fifty-six patients with newly diagnosed type 2 diabetes mellitus(T2DM group), 52 patients with impaired glucose tolerance(IGT group), and 42 subjects with normal glucose tolerance(NGT group)underwent intravenous glucose tolerance test. Fasting serum SFRP4 and interleukin(IL)-1β were assayed by ELISA. Acute insulin response(AIR), the area under the curve of the first-phase(0-10 min)insulin secretion(AUC), glucose disposition index(GDI), homeostasis model assessment for β cell function index(HOMA-β), and insulin resistance index(HOMA-IR)were calculated. Results (1)The levels of SFRP4 and IL-1β in T2DM group and IGT group were significantly higher than that in NGT group[(184.38±61.34 or 141.64±40.46 or 95.46±20.13)ng/ml, P<0.01]. AIR, AUC, and GDI in T2DM group and IGT group were significantly lower than those in NGT group(P<0.01), and these results were more significantly reduced in T2DM group compared with those in IGT group.(2)SFRP4 was negatively correlated with AIR, AUC, GDI, HOMA-β(P<0.01), and positively correlated with fasting plasma glucose, 2 h plasma glucose after glucose loading, HbA1C, IL-1β, and high sensitive C-reactive protein(P<0.01). (3)Multiple stepwise regression analysis showed that AUC, HOMA-IR, and serum IL-1β level were independently associated with SFRP4. Conclusion The concentration of serum SFRP4 is closely correlated with the glycolipid metabolic disorder, the first-phase of glucose-stimulated insulin secretion, and chronic low-grade inflammation. SFRP4 may be involved in the mechanism of β cell dysfunction in type 2 diabetes mellitus. Key words: Secreted frizzled-related protein 4; β-cell function; Intravenous glucose tolerance test; Interleukin-1β; Diabetes mellitus, type 2