Evaluation of Serum Adipocytokines and Cystatin C As Early Biomarkers in Chronic Kidney Disease Patients and Their Relation to Endothelial Dysfunction.

Background Chronic kidney disease (CKD) is strongly associated with an increased incidence of cardiovascular complications. One of the mechanisms contributing to vascular damage in CKD is the decreased availability of nitric oxide (NO), an important regulator of vascular tone and endothelial function. The adipocytokines have been suggested to play a significant role in the vascular abnormalities observed in patients with impaired renal function. Methods This study included 81 patients diagnosed with CKD who were classified into three groups based on their estimated glomerular filtration rate (eGFR). Group I (n=27) consisted of patients with eGFR values ranging from 60-90 ml/min/1.73 m² (CKD stages I-II). Whereas, group II (n=27) included patients with eGFR levels between 15-59 ml/min/1.73 m² (stages III-IV), while group III (n=27) comprised patients with eGFR values below 15 ml/min/1.73 m² (stage V). The serum concentrations of adiponectin, leptin, cystatin C, and endothelial nitric oxide synthase (eNOS) were measured using commercially available enzyme-linked immunosorbent assay (ELISA) kits (Elabscience, Houston, Texas, USA). Results In the present study, the serum levels of adiponectin, leptin, and cystatin C increased progressively from group I to group III, which was statistically significant (p<0.05). In contrast, serum eNOS levels showed a decreasing trend with advancing stages of kidney disease. The random blood sugar (RBS) and serum creatinine levels were significantly higher (p<0.05) in patients belonging to group III compared with group II and group I. The correlation analysis revealed a strong negative association between eGFR and serum eNOS levels in groups III, II, and I (r= -0.72, -0.56, and -0.22, respectively). Conclusion The findings of this study indicate that worsening renal function in CKD is associated with significant alterations in circulating adiponectin, leptin, and cystatin C levels. These biochemical changes, together with reduced eNOS activity, may contribute to endothelial dysfunction and could increase the risk of cardiovascular complications in patients with CKD.