Connective Tissue Growth Factor Is Increased in Plasma of Type 1 Diabetic Patients With Nephropathy

Abstract

OBJECTIVE—Connective tissue growth factor (CTGF) is strongly upregulated in fibrotic disorders and has been hypothesized to play a role in the development and progression of diabetes complications. The aim of the present study was to investigate the possible association of plasma CTGF levels in type 1 diabetic patients with markers relevant to development of diabetes complications. RESEARCH DESIGN AND METHODS—Plasma CTGF levels (full-length and NH2-terminal fragments) were determined in 62 well-characterized patients with type 1 diabetes and in 21 healthy control subjects. Correlations of these plasma CTGF levels with markers of glycemic control, platelet activation, endothelial activation, nephropathy, and retinopathy were investigated. RESULTS—Elevated plasma NH2-terminal fragment of CTGF (CTGF-N) levels were detected in a subpopulation of type 1 diabetic patients and were associated with diabetic nephropathy. Stepwise regression analysis revealed contribution of albuminuria, creatinine clearance, and duration of diabetes as predictors of plasma CTGF-N level. Elevation of plasma CTGF-N levels in patients with retinopathy was probably due to renal comorbidity. CONCLUSIONS—Plasma CTGF-N levels are elevated in type 1 diabetic patients with nephropathy and appear to be correlated with proteinuria and creatinine clearance. Further studies will be needed to determine the relevance of plasma CTGF as a clinical marker and/or pathogenic factor in diabetic nephropathy.