Serum myostatin level is a positive predictor of endothelial function measured by digital thermal monitoring of vascular reactivity in kidney transplantation patients

Objectives: Myostatin is a myokine predominantly expressed and secreted in skeletal muscle in response to stimulations, including oxidative stress or inflammation. We investigated a potential association between myostatin levels and endothelial function among kidney transplantation (KT) patients. Materials and Methods: Fasting blood samples were collected from 64 KT patients. The endothelial function that indicated by vascular reactivity index (VRI) was measured by digital thermal monitoring test. Serum myostatin levels were measured using a commercial enzyme-linked immunosorbent assay kit. All patients were categorized into three groups according to their VRI values: poor vascular reactivity was considered if VRI <1.0; 1.0 <= VRI <2.0 indicated intermediate vascular reactivity, and VRI >= 2.0 was grouped as good vascular reactivity. Results: Seven KT patients (10.9%) were categorized as poor vascular reactivity, 24 KT patients (37.5%) were grouped as intermediate vascular reactivity, and 33 KT patients had good vascular reactivity. Advanced age (r = -0.372, P = 0.002) and serum alkaline phosphate (ALP) level (r = -0.341, P = 0.006) were negatively correlated with VRI. However, serum myostatin level (r = 0.430, P < 0.001) was positively correlated with VRI. In multivariable forward stepwise linear regression analysis, high serum level of myostatin (beta = 0.441, adjusted R2 change = 0.171; P < 0.001), advanced age (beta = -0.317, adjusted R2 change = 0.138; P = 0.003), and serum ALP level (beta = -0.270, adjusted R2 change = 0.060; P = 0.011) were significantly associated with VRI in KT patients. Conclusion: Our study showed that fasting myostatin level was positively associated with VRI and endothelial function among KT patients.