Association of retinol binding protein-4, cystatin C, homocysteine and high-sensitivity C-reactive protein levels in patients with newly diagnosed type 2 diabetes mellitus

Introduction: To investigate the serum retinol binding protein (RBP)-4, cystatin C (Cys C), homocysteine (HCY) and high-sensitivity C-reactive protein (hs-CRP) levels in newly diagnosed type 2 diabetes mellitus (NT2DM) patients, prediabetes mellitus (PDM) subjects and normal controls, as well as their correlation with clinical and laboratory indexes, such as blood pressure and lipoprotein.

Material and methods: A total of 242 subjects, including 141 NT2DM patients, 48 PDM subjects and 53 healthy controls, were recruited in the present study. Serum RBP-4, Cys C and hs-CRP concentrations were measured by enzyme-linked immunosorbent assay (ELISA). HCY concentration was determined by the chemical luminescence method.

Results: There were significant differences in Cys C and hs-CRP among NT2DM patients, PDM subjects and normal controls. In comparison to controls, there were significantly elevated Cys C and hs-CRP levels in PDM (both p < 0.001), and a significantly increased Cys C level in NT2DM (p < 0.001); however, there were no significant differences in Cys C and hs-CRP levels between NT2DM and PDM, and no significant differences of hs-CRP levels between NT2DM and normal controls. No significant differences of RBP-4 and HCY levels among NT2DM, PDM and normal control groups were observed.

Conclusions: Aberrant Cys C expression and its clinical associations in NT2DM suggest their important role in this disease.