ABSTRACT
It is well established that the detection of microalbuminuria in patients with diabetes mellitus indicates the presence of glomerular involvement in early renal damage. Recent studies have demonstrated that there iso also a tubular component of renal complications in diabetes, as shown by the detection of renal tubular proteins and enzymes in urine. So, the objective of this study was to determine the activity of urinary enzymes [N-aceiyl-beta-D-glucosaminidase [NAG], a lysosomal enzyme, gamma-glutamyltranspeptidase [GGT], alkaline phosphalase [ALP], brush border enzymes and /32 microglobulin [beta 2MG,] as one of the tubular proteins] as markers of tubular damage which may reflect early stage of diabetic nephropathy [DN] and to clarify the importance of estimation of these enzymes as noninvasive cheap tools in monitoring the course of DN [degree of proteinuria]. Also we studied the serum level of angiolensine converting enzyme [ACE] to evaluate the endothelial disorder in diabetic patients. Patients and Methods: 3 groups of non smoker type 2 diabetic patients were studied, 1[st] group was 20 normo-albuminuric diabetic patients, 2[nd] group was 20 patients with microalbuminurea [urinary albumin is >30 mg - <300 mg/day], and the 3[rd] group was 20 patie!ts with macroalbuminuria [: 300 mg/day]. Another 15 healthy age and sex matched subjects were recruited as a control group. For each patient and control subject the followings were estimated: [1] urinary glucose, 2 hours postprandial blood glucose, and glycated haemoglohin as parameters of gl, vcaemic control [2] blood urea, serum creatinine, 24-hour urinary protein and microalbuminuria to detect DN, ['3,] Serum ACE, urinary NAG. ALP, GGT and beta 2 microglobulin. The serum urinary NAG, ALP, beta 2MG, HbA[1c] and 2-hour postprandial blood glucose were significantly higher in the diabetic groups compared to controls. While GGT was significantly lower in the diabetic groups compared to controls. Also the increase in serum ACE, urinary NAG, ALP and beta 2MG positively correlated with the degree of albuminuria, HbA[1c] and 2-hour postprandial blood glucose while urinary GGT negatively correlated with the previous parameters. The significant progressive increase in ACE activity in the studied groups supports the hypothesis of ACE activity being an essential partner in the development of DN The elevation of the levels of NAG, ALP and beta 2 microglobulin, and the decrease in the level of GGT in the first group and the progressive change in their levels with the pathological increase in the level of urinary albumin, suggest that these changes are useful in the diagnosis of early stage of DN before the development of microalbuminuria. GGT and NAG appear more simple and readily available compared with others