Evaluation of renal glomerular and tubular markers in type I diabetics without clinical proteinuria and relation to B-cell function

ABSTRACT

To evaluate the value of microalbuminuria, urinary B2 microglobulin [B2M] and urinary N-acetyl B-D-glucosaminase [NAG] in the assessment of renal glomerular and/or tubular impairment in type 1-insulin dependent diabetic patients without clinical proteinuria and to try to clarify the relationship of these parameters with the occurrence of diabetic nephropathy and with the pancreatic B-cell function; 30 insulin dependent diapetic patients and 10 healthy normal controls were selected. Urinary C-peptide was measured in 2 hours urine collection after oral glucose load. Serum and urinary B2M, microalbuminria, urinary NAG, serum and urine creatinine and blood glucose were measured to both subjects and controls. A significant reduction in the level of C-peptide among diabetics was evident [P < 0.001]. A highly significant increase in microalbuminuria urinary B2M and urinary NAG was observed in diabetics[P < 0.001]. The incidence of abnormal increase in microalbuminuria was 80%, urinary B2M was 73. 3% and urinary NAG was 46. 67%. Mixed type proteinuria with high levels of both microalbuminuria and B2M was observed in 59.97% of diabetics. Microalbuminria was inversely related to urinary C-peptide. These data suggests that an early impairment might develop in glomeruli and/or tubules in type 1 diabetics before the occurrence of overt nephropathy and the measurement of Microalbuminria, urinary B2M and NAG are reliable methods to detect this early damage before the development of irreversible diabetic nephropathy