The Plasma Osteoprotegerin Level and Osteoprotegerin Expression in Renal Biopsy Tissue are Increased in Type 2 Diabetes with Nephropathy

摘要

Objective: To investigate the plasma osteoprotegerin level and osteoprotegerin expression in renal biopsy tissue in type 2 diabetes with nephropathy. Methods: Plasma osteoprotegerin level was measured by enzyme- linked immunoassay in 48 type 2 diabetes with normoalbuminuria, 48 patients with microalbuminuria, 44 patients with macroalbuminuria and 40 healthy persons. Part of diabetes patients with nephropathy were performed kidney biopsy by ultrasound guide. The osteoprotegerin expression in kidney biopsy tissue is examined by immunohistochemistry. Results: The plasma osteoprotegerin levels were signifi cantly elevated in patients with microalbuminuria ( 3.73 0.75 ng/ l) and macroalbuminuria ( 4.68 0.82 ng/ l) as compared with patients with normoalbuminuria ( 2.71 0.69 ng/ l) and control subjects ( 2.11 0.42 ng/ l). And the plasma osteoprotegerin level in macroalbuminuric group was also higher than that in microalbuminuria group. The plasma osteopro-tegerin level had a positive correlation with the fasting plasma glucose ( FPG), 2- h plasma glucose ( 2hPG), glycohemoglobinA1c ( HbA1C), high sensitive C- reactive protein ( hsCRP) and log( UAER). Multivariate regression analysis revealed that plasma osteoprotegerin level was an independent factor associated with albuminuria in type 2 diabetes. The immunohistochemistry results showed that positive immunostaining for osteoprotegerin was observed in the renal tubule cells of biopsy and not in glomerulus, and the osteoprotegerin expression was higher in macroalbuminuria group than that in microalbuminuria group. Conclusions: The plasma osteoprotegerin level and the osteoprotegerin expression in renal tubule cells of biopsy tissue were increased in nephropathy of type 2 diabetes. This fi nding supports the growing concept that osteoprotegerin may act as an important regulatory molecule in the angiopathy, and particularly, that it may be involved in the occurrence and development of nephropathy in type 2 diabetes.