Urinary excretion of proinflammatory cytokines and transforming growth factor beta at early stages of diabetic nephropathy

Aim. To examine correlations between urine excretion of proinflammatoty cytokines, transforming growth factor beta (TGF-b) and changes in renal structure and function, quality of glycemia control in patients with type I diabetes mellitus. Material and methods. Urinary excretion of interleukine 1-beta (IL-1b), monocytic chemoattractive protein-1 (MCP-1), RANTES and TGF-b was measured with enzyme immunoassay in 57 patients including 22 patients with normal albuminuria, 23 - with microalbuminuria, 12 - with macroalbuminuria. Creatinine clearance was subnormal in 8 patients with macroalbuminuria. The control group consisted of 10 healthy persons. Morphological examination of renal biopsies was performed in 8 patients with normoalbuminuria and 10 patients with microalbuminuria. Results. Patients with normoalbuminuria had excretion of MCP-1 significantly higher than in controls. Microalbuminuria patients showed high excretion of LL-1b, MCP-1 and TGF-b. Excretion of LL-1b, MCP-1 RANTES and TGF-b in patients with macroalbuminuria was higher than in controls and other groups of patients. Excretion of cytokines and TGFb correlated inversely with glomerular filtration rate and hemoglobin level. Positive correlations were detected between excretion of LL-1b, MCP-1, TGFb and glycated hemoglobin A(lc). In patients with normo- and microalbuminuria cytokine and TGFb excretion correlated with thickness of glomerular and glomerular basal membrane. CD68-positive macrophages were detected in the intersticium of 1 patient with normoalbuminuria and 6 patients with microalbuminuria. Conclusion. Urinary excretion of proinflammatory cytokines and TGF-b was elevated inpatients with DM-1 having micro- and macroalbuminuria suggesting participation of inflammation in development of diabetic nephropathy.