The relationship between serum fetuin-A, cystatin-C levels, and microalbuminuria in patients with metabolic syndrome

Abstract

Background: The metabolic syndrome, syndrome X, is a group of metabolic disorders in which insulin resistance plays a pivotal role. The MS is an important risk factor for subsequent development of type 2 diabetes and cardiovascular disease. Fetuin-A is a liver derived blood protein that acts as effective inhibitor of soft tissue calcification. Cystatin C is a useful marker in measuring glomerular filtration rate. Moreover, recently it has been suggested that cystatin C may be a potential biomarker for detecting microalbuminuria. Microalbuminuria (MA) is a strong indicator of morbidity related to cardiovascular disorders, and is currently considered a novel diagnostic criterion for MS. It has been also demonstrated that the increased serum fetuin-A levels is associated with several parameters of MS. In this study, we attempted to investigate the relationship between serum fetuin-A, cystatin-C levels and microalbuminuria in patients with MS.

Methods: A total of 50 patients with MS and 25 control were included in this study. We defined MS by the NCEP criteria among nondiabetic outpatients. Patients with MS were further divided into two groups based on MA status. Overall 25 of the participants with MS did not have MA (group I), while the remaining 25 had MA (group II). None of the subjects in the healthy control group (group III) had laboratory findings supporting the presence of MA. The serum fetuin-A and cystatin-C levels were measured using ELISA.

Results: Age, distributions of sex, BP and LDL cholesterol levels were similar among all groups. BMI, Waist/hip ratio, FBG, HOMA-IR, total cholesterol, trigliserid, CRP levels were significantly higher in group I and group II compared to control. In group II, the cystatin-C and fetuin levels were higher than control. While the cystatin-C levels were higher in group II compared to group I, the fetuin levels did not different. Morever, the fetuin A and cystatin-C concentrations were positively correlated with microalbuminuria (r = 0.26, p = 0.02; r = 0.50, p = 0.0001, respectively).

Conclusion: In our study, we found that MS patients with microalbuminuria had high levels of fetuin-A and cystatin-C. In conclusion, we suggest that determination of fetuin-A and cystatin C levels could be useful marker as an early indicator of renal injury in patients with MS.

Keywords: cystatin-C; fetuin-A; metabolic syndrome; microalbuminuria.