Correlation of Histological and Clinical Parameters in Patients with Renal Biopsy Diagnosis of Diabetic Nephropathy
Melissa Much, Gilbert Moeckel. Yale University School of Medicine, New Haven, CT
Background: The pathologic diagnosis of diabetic nephropathy (DN) in the renal biopsy is based on a constellation of morphologic findings that include glomerular changes such as tuft enlargement, basement membrane thickening, mesangial expansion and nodular mesangial sclerosis. Extraglomerular features of DN include increased tubular basement membrane thickness, interstitial fibrosis, arteriolar hyalinosis and intimal fibrosis of arterioles and interlobular arteries. Commissioned by the Renal Pathology Society (RPS), Tervaert et al. (JASN 21:556, 2010) published a pathologic classification system of DN based predominantly on glomerular lesions to grade DN. The goal of our study is to correlate the severity of morphologic findings of DN to clinically documented duration of disease and to the course of clinical parameters of kidney function and other laboratory data throughout this period.
Design: Renal biopsies from 30 patients with the sole biopsy diagnosis of either mild, moderate or severe DN were retrospectively selected from our biopsy repository and evaluated for the presence and severity of glomerular, interstitial, vascular and tubular lesions. The biopsies were then scored according to the RPS classification of DN. The patient's clinical charts and laboratory data bases were evaluated for documented duration of disease, course of serum creatinine and BUN values, severity of proteinuria, presence of hypertension and course of serum glucose and Hb A1c levels. The histological findings and respective RPS DN scores were then correlated to the duration of disease, the course of serum creatinine, glucose, HB A1c and urine protein levels throughout the clinically documented disease period.
Results: We find that longer clinical duration of diabetes correlates positively with higher RPS class lesions in the biopsies. Higher RPS class biopsies show also increased % interstitial fibrosis, arteriolar hyalinosis and higher levels of proteinuria. Moreover, we find that interstitial fibrosis independently correlates with vascular hyalinosis and the duration of diabetic disease.
Conclusions: Our findings show that increased severity of interstitial and vascular pathologic changes in DN correlate with more severe glomerular lesions and therefore higher RPS classes. Moreover, increase in interstitial fibrosis correlates independently with higher degree of vascular hyalinosis. Our findings raise the question whether vascular hyalinosis plays a role in progression of diabetic nephropathy or could be a potential marker of disease progression.
Category: Kidney (does not include tumors)
Monday, March 4, 2013 1:00 PM
Poster Session II # 242, Monday Afternoon