Purpose: This study aimed to investigate the relationship between serum isthmin-1 (ISM1) and type 2 diabetes mellitus (T2DM), and the alteration of serum ISM1 level in both diabetic sensorimotor peripheral neuropathy (DSPN) and diabetic adults with obesity.
Patients and Methods: We recruited 180 participants (120 T2DM and 60 controls) in the cross-sectional study. First, we compared the serum ISM1 concentration in diabetic patients and non-diabetic controls. Secondly, according to DSPN, patients were divided into DSPN and non-DSPN groups. Last, patients were categorized as lean T2DM (15 males, 15 females), overweight T2DM (35 males, 19 females), and obese T2DM groups (23 males, 13 females) according to gender and body mass index (BMI). All participants were collected with clinical characteristics and biochemical profiles. Serum ISM1 was detected in all subjects by ELISA.
Results: Higher serum ISM1 [7.78 ng/mL (IQR: 6.33– 9.06) vs 5.22 (3.86– 6.04), P < 0.001] was observed in diabetic patients compared to non-diabetic controls. Binary logistic regression analysis showed that serum ISM1 was a risk factor for type 2 diabetes after adjustment (OR=4.218, 95% CI: 1.843– 9.653, P =0.001). Compared to the non-DSPN group, serum ISM1 level was not changed significantly in patients who suffered from DSPN. Diabetic females with obesity had lower level of serum ISM1 (7.10± 1.29 ng/mL) when compared to the lean T2DM (8.42± 1.36 ng/mL, P < 0.05) and the overweight T2DM (8.33± 1.27 ng/mL, P < 0.05). However, serum ISM1 was not changed significantly in male groups or all patients together.
Conclusion: Serum ISM1 was a risk factor for type 2 diabetes, and it was associated with diabetic adults with obesity while there was sexual dimorphism. However, serum ISM1 levels were not correlated with DSPN.
Keywords: isthmin-1, type 2 diabetes, diabetic sensorimotor peripheral neuropathy, obesity, inflammation