Preptin and myostatin independently increase in pre-diabetics and patients of type 2 diabetes mellitus

The relation between serum preptin, myostatin, insulin, and also homeostatic model assessment-insulin resistance were examined in pre-diabetes persons and newly diagnosed patients with overt type 2 diabetes mellitus. 84 subjects were included in the study and assigned into three groups: normoglycemic participants (group 1 = 27), pre-diabetes (group 2 = 30), and T2DM (group 3 = 29). Serum insulin, preptin, and myostatin levels were measured with immunoradiometric assay (IRMA), enzyme-linked immunosorbent assay (ELISA), and chemiluminescent immunoassay (CLIA), respectively. Patients with T2DM had higher levels of preptin compared to normoglycemics (461.25 ± 53.90 vs. 407.54 ± 54.78, P < 0.001). Furthermore, these patients had elevated levels of myostatin compared with controls (2710.60 ± 559.09 vs. 2246.37 ± 416.40, P < 0.001). Preptin and myostatin both positively correlated with serum insulin (r = 0.369, P = 0.01, and r = 0.309, P = 0.04, respectively). However, no significant association was found between serum preptin and myostatin levels. Stepwise multiple regression analysis showed that insulin was affected more by preptin, with only a trivial contribution from myostatin. Serum preptin and myostatin levels increase in pre-diabetic subjects and even further in type 2 diabetic patients. The correlation between preptin and insulin evolves when pre-diabetes or overt type 2 diabetes develops. Moreover, serum myostatin increases in association with insulin and not HOMA-IR in diabetic conditions.