Effect of Metformin on Fibroblast Growth Factor-21 Levels in Patients with Newly Diagnosed Type 2 Diabetes.

Background: Fibroblast growth factor (FGF)-21 is an important regulator of glucose metabolism. In the present study, we investigated whether plasma levels of FGF-21 changed in patients with newly diagnosed type 2 diabetes mellitus (T2DM) and assessed the effects of metformin treatment on plasma FGF-21 levels.

Materials And Methods: The plasma FGF-21 levels and the metabolic parameters of 226 patients with newly diagnosed T2DM and 100 sex- and age-matched normal glycemic tolerant (NGT) controls were measured. Seventy-four patients among of the 226 patients with T2DM were treated with metformin throughout the 12-week study period. The fasting plasma FGF-21 and high-sensitivity C-reactive protein (hs-CRP) levels were measured using enzyme-linked immunosorbent assay kits.

Results: The patients with T2DM had significantly higher fasting plasma FGF-21 levels (302.2 pg/mL [range, 201.3-454.4 pg/mL] vs. 104.5 pg/mL [range, 71.6-185.6 pg/mL]; P < 0.00) and hs-CRP levels (2.63 ± 2.81 mg/L vs. 1.58 ± 2.16 mg/L; P < 0.00) than the NGT subjects. The fasting plasma hs-CRP and FGF-21 levels were significantly decreased in the T2DM group after metformin treatment compared with pretreatment (respectively, 2.56 ± 1.75 mg/L vs. 3.28 ± 1.89 mg/L [P < 0.05] and 232.6 pg/mL [range, 154.3-307.8 pg/mL] vs. 313.9 pg/mL [range, 227.7-474.2 pg/mL] [P < 0.01]).

Conclusions: In patients with T2DM, the plasma FGF-21 levels are increased but are significantly decreased after metformin treatment. Metformin may play a role in reducing the FGF-21 levels in patients with T2DM, likely through the amelioration of glucose-lipid metabolism and inflammation.