Background

The aim of this study is to investigate the changes in serum irisin, FGF21, FSTL1, visfatin, and Metrnl levels in response to exercise and/or diet therapy in patients with obesity and co-morbidities like type 2 diabetes (T2DM) or insulin resistance (IR).

Methods

A total of 48 subjects with obesity (24 with T2DM and 24 with IR) and 24 healthy control subjects participated in this study. Subjects with obesity divided into 2 groups as diet intervention (DI) and diet and exercise intervention (DEI) and subjects received individually planned exercise and/or diet therapy for 12 weeks. Serum adipokines and myokines levels, anthropometric measurements, and biochemical parameters were assessed at the beginning, 4th, and 12th week of the study. Data are adjusted for %weight loss.

Results

Results showed that baseline irisin levels were higher in T2DM and IR groups than control group (p<0.001). In addition, baseline visfatin and FSTL1 levels were increased in T2DM individuals in comparison to IR and healthy subjects. However, baseline Metrnl levels were higher in IR group compared to T2DM (p=0.001). FGF21, visfatin, and FSTL1 levels were decreased at 12th week in T2DM (p<0.05), while irisin levels at 12th week increased in comparison to 4th week’s levels (p=0.008). Irisin, FGF21, and FSTL1 levels were decreased at 4th week in IR subjects (p<0.05). Metrnl levels reduced at 12th week (p<0.001). Adipokine and myokine levels have not differed between DI and DIE groups throughout the study (p>0.05). Irisin level and muscle mass and FGF21 level and body weight were found positively correlated (p<0.05). FSTL1 level and waist/hip ratio were found negatively correlated (p<0.05). Visfatin levels were positively correlated with HbA1c levels in T2DM at 12th week (p=0.026).

Conclusions

Although serum myokine and adipokine levels were found to be different in obesity with different co-morbidities like T2DM or IR, both DI and DEI combination therapies seems to have a similar effect on these myokine and adipokine levels.