In this study we measured the 24 hours urinary activity of two renal tubular enzymes;
N-acetyl fl-D-glucosaminidase (NAG) and y-glutamyl transpeptidase (GGTP)
that originate from renal proximal tubular cells, in addition to 24 hours urinary
excretion of 132-microglobulin to evaluate renal tubular function in 33 noninsulin
dependent diabetic patients (NIDD patients) recently discovered and not yet treated
from diabetes mellitus. For all these diabetics fasting and 2 hours post prandial blood
sugar were evaluated, in addition to estimation of glycosylated haemoglobin and
urinary albumin in 24 hours, and these diabetic patients were classified into 3
subgroups according to their urinary albumin excretion/24 hours; (I) 12 diabetics with
normoalbuminuria (urinary albumin <30 mg/24 hours); (2) 11 diabetics with
microalbuminuria (urinary albumin from 30-300 mg/24 hours); (3) 10 diabetics with
macroalbuminuria (urinary albumin >300 mg/24 hours). Fifteen apparently healthy
volunteers were taken as normal controls. And we get the following results:
- The urinary activity of NAG was significantly increased while that of GGTP
was significantly decreased in all diabetic subgroups compared to control subjects
(P4).01) and in diabetics with either micro-or macroalbuminuria compared to diabetics
with normoalbuminuria (P<0,01) and in diabetics with macroalbuminuria compared
to diabetics with microalbuminuria (P<0.01).
- Urinary 132-microglobulin increased significantly only in diabetics with macroalbuminuria
compared to controls and to other diabetic subgroups (P<0.01).
- NAG correlated significantly positive while GGTP correlated significantly
negative with fasting blood sugar (r=0.508, P<0.01 and r = -0.491, P<0.01
respectively), glycosylated haemoglobin (r = 0.552, P<0.01 and r = -0.481 P<0.01
respectively), and urinary albumin (r=0.527, P<0.01 and 1=-0.475, P<0.01
respectively), in all NID diabetics.
From this study we conclude that there is renal tubular cell dysfunction in
non-insulin dependent diabetic patients as evidenced by these changes in the enzyme
activity of both NAG and GGTP in 24 hours urine, in addition to 24 hours urinary
excretion of 132 microglobulin and this tubular dysfunction may precede glomerular
alterations as evidenced by the significant changes in these urinary enzymes activities
even in the normoalbuminuric diabetics. And we recommend measurement of these
renal tubular cell enzymes as markers of renal tubular cell dysfunction. Their
measurement is non-invasive and inexpensive. In addition we also recommend early
and proper management of diabetes as this will reverse the renal tubular cell
dysfunction in the early stage of the disease. |
