Serum fibroblast growth factor 19 and endogenous islet beta cell function in type 2 diabetic patients
Abstract Background Fibroblast growth factor 19 (FGF19) takes part in maintaining the balance of glycolipids and may be involved in regulating the secretory activity of islet beta cells in patients with type 2 diabetes. This study aimed to evaluate the relationship between the levels of serum FGF19 and endogenous islet beta cell function in type 2 diabetic patients. Methods Samples were obtained from 271 subjects: 85 drug-naïve type 2 diabetes participants exclusively on lifestyle intervention (N-DM group), 122 type 2 diabetes subjects previously used medications (DM group) and 64 normal controls (NC group). Serum FGF19 concentrations were measured by ELISA. The insulin sensitivity (MI), insulin secretion (AUCins/AUCglu) and insulin secretion-sensitivity index-2 (ISSI-2) were also measured in the N-DM and DM. Results Serum FGF19 levels decreased, in order, from the NC group [median (interquartile range), 245.03 (126.23–317.43) pg/mL] to the N-DM group [170.05 (89.01–244.70) pg/mL] and, finally, to the DM group [142.25 (55.55–187.58) pg/mL] (p for trend < 0.05). Among subjects in the DM group, there was a positive trend in the serum FGF19 concentration; plasma insulin levels at 60 min, 120 min (INS60, INS120, respectively); and area under the insulin curve (AUCins) at two points (r = 0.214, p = 0.025; r = 0.189, p = 0.048; r = 0.188, p = 0.049). However, the differences were no longer observed among the N-DM subjects. Simultaneously, the ISSI-2 was closely related to the serum FGF19 levels (r = 0.297, p = 0.002) among DM subjects. Furthermore, after adjusting for age, sex, duration, therapy and other clinical factors via multiple logistic regression analysis, ISSI-2 was a key independent factor in the levels of FGF19 (β = 0.281, t = 2.557, p = 0.013). Conclusions The serum FGF19 level has a close relation with endogenous beta cell function among DM subjects, as assessed by the ISSI-2. As ISSI-2 is higher in N-DM group, FGF19 may be a main protector in dysfunction of beta cell.
