Plasma endothelin-1 levels and albuminuria in patients with type 2 diabetes mellitus

Introduction. Microalbuminuria is a very important independent risk factor for the progression of renal diseases as well as diseases of the cardiovascular system. Pathophysiological mechanisms that lead to the development of microalbuminuria in patients with diabetes are complex and they are a result of numerous factors. In the past decade, endothelin-1, the most potent vasoconstrictor peptide, was identified as an important factor that significantly contributes to the functional and structural renal changes. The objective of this study was to investigate the relationship between plasma concentration of endothelin-1 and urinary albumin excretion in patients with type 2 diabetes mellitus. Material and Methods. There were 76 patients with type 2 diabetes who were divided into those having normoalbuminuria (n=33), microalbuminuria (n=29), and macroalbuminuria (n=14), and 30 healthy controls. Plasma levels of endothelin-1 were measured by enzyme-linked immunosorbent assay. Results. There were significant differences in plasma concentration of endothelin-1 among groups (p<0.01). The correlation between endothelin-1, albuminuria, proteinuria and glomerular filtration rate was significant. In multiple regression analyses the plasma concentration of endothelin-1 was independently and significantly associated with albuminuria (β=0.01, p=0.009), proteinuria (β=0.02, p<0.001) and glomerular filtration rate (β=-0.01, p=0.0006). Conclusion. Higher plasma concentrations of endothelin-1 are independently associated with the levels of urinary excretion of albumin which may corroborate the hypothesis of a potential role of this peptide in the development of microalbuminuria in diabetic nephropathy.