Evaluating Urinary Thrombospondin 2 (TSP-2) Levels in Patients with Diabetic Nephropathy: A Cross-Sectional Study

Abstract

Background: In diabetic nephropathy, changes in the renal microenvironment can lead to increased fibrosis and inflammation, processes in which thrombospondin-2 (TSP-2) may be implicated.

Objective: To determine urinary thrombospondin-2 levels in patients with diabetic nephropathy.

Methods: This was a hospital-based cross-sectional study conducted in the Department of Biochemistry, Vinayaka Mission's Kirupananda Variyar Medical College and Hospital, Tamil Nadu, India between January 2024 and June 2024. The study included 40 healthy individuals as controls (Group A) and 120 diabetic patients diagnosed with nephropathy, up to stage 3 classification based on urinary albumin levels [Group B, patients with normoalbuminuria (UACR <30mg/g); Group C, microalbuminuria (UACR between 30 and 300mg/g); and Group D, macroalbuminuria (UACR >300mg/g)].

Results: The study found significant differences in alcoholism prevalence, BMI, and diabetes duration among the groups. Group D had the highest prevalence of alcoholism (37.5%, p = 0.010). BMI progressively increased from Group A (23.8 ± 2.5 kg/m²) to Group D (28.4 ± 3.9 kg/m², p = 0.004). Diabetes duration was longest in Group D (10.1 ± 3.1 years) and shortest in Group B (6.5 ± 2.3 years, p < 0.001). No significant differences were noted in smoking, blood pressure, or hypertension. Blood glucose and HbA1c levels were significantly higher in diabetic groups (p < 0.001), with Group A having the lowest mean glucose level (98.5 ± 12.4 mg/dL) and Group C the highest (280.2 ± 105.6 mg/dL). Insulin levels did not differ significantly among groups (p = 0.987). Lipid profile variations were not statistically significant, including cholesterol (p = 0.231), triglycerides (p = 0.180), HDL (p = 0.975), LDL (p = 0.328), and VLDL (p = 0.865). Urinary TSP-2 levels showed no significant differences across groups (p = 0.702). Correlation analysis indicated no significant associations between TSP-2 and clinical parameters, including UACR, glucose, HbA1c, and creatinine. ROC analysis for TSP-2 as a diagnostic marker for diabetes and macroalbuminuria yielded poor discriminatory performance (AUC = 0.504 and 0.528, respectively).

Conclusion: The study found that urinary thrombospondin-2 levels do not significantly differ among diabetic patients with varying degrees of nephropathy and do not serve as a reliable biomarker for diabetes or renal impairment.