[Antihypertensive therapy in diabetes mellitus]

Urinary Lysosomal Enzyme Activities and Albuminuria in Ghanaian Patients with Type 2 Diabetes Mellitus

Renal tubular lysosomal enzyme activities like alanine aminopeptidase (AAP) and N-acetyl-β-D-glucosaminidase (NAG) have been shown to increase in patients developing diabetic nephropathy and nephrosclerosis. This study aimed to determine the activities of N-acetyl-β-D-glucosaminidase and alanine aminopeptidase and albumin concentration in urine samples of patients with type 2 diabetes. One hundred and thirty (65 type 2 diabetic and 65 nondiabetic) subjects participated in this study. Blood samples were drawn for measurements of fasting blood glucose, albumin (Alb), lipids, and creatinine (Cr). Early morning spot urine samples were also collected for activities of alanine aminopeptidase (AAP), N-acetyl-β-D-glucosaminidase (NAG), and concentration of albumin (U-Alb) and creatinine (U-Cr). Both NAG/Cr and AAP/Cr were significantly increased in diabetic subjects compared to controls (p < 0.001). There was positive correlation between NAG/Cr and Alb/Cr (r = 0.49, p < 0.001) and between NAG/Cr and serum creatinine (r = 0.441, p < 0.001). A negative correlation was found between NAG/Cr and eGFR (r = −0.432, p < 0.05). 9.3% and 12% of diabetics with normoalbuminuria had elevated levels of AAP/Cr and NAG/Cr, respectively. We conclude that measuring the urinary enzymes activities (NAG/Cr and AAP/Cr) could be useful as a biomarker of early renal involvement in diabetic complications.

Urinary N-acetyl beta glucosaminidase and gamma glutamyl transferase as early markers of diabetic nephropathy

Albumin and enzymes-N-acetyl-beta-glucosaminidase (NAG) and gamma glutamyl transferase (GGT) were estimated in the morning random urine samples of 196 albustix negative diabetic patients to evaluate the clinical utility of these urinary enzymes as early markers of diabetic nephropathy. Albumin was estimated by immunoturbidimetric method and enzymes by linetic essay within six hours of voiding of urine. The urinary albumin and urinary enzyme concentration was calculated in terms of ratio with respect to urinary creatinine. Correlation coefficient (r) bewween urinary albumin and urinary enzymes in normoalbuminuric, microalbuminuric and overall diabetic cases was 0.23, 0.32 and 0.40 respectively for NAG, and 0.08, 0.06 and 0.18 respectively for GGT. NAG excretion was found increased in 34%, 63.7% and 49.5% of normoalbuminuric, microalbuminuric and overall diabetic cases respectively while GGT in 6.4%, 24.5% and 15.8%. The correlation coefficient between urinary albumin and NAG in normoalbuminuric, microalbuminuric, and overall diabetic patients with increased NAG excretion was found only 0.31, 0.27 and 0.35 respectively. No correlation was found between duration of diabetes and enzyme excretion. The study suggests that urinary NAG or GGT or both together do not have any clinical significance as an early marker of diabetic nephropathy.