Study on the relation between renal tubular disorders and glomerular dysfunction in the early phase of insulin-dependent diabetes mellitus in children.

To study the relations between renal tubular disorder and glomerular dysfunction in the early phase of insulin-dependent diabetes mellitus (IDDM), we performed concomitant measurements of urinary beta-D-N-acetyl glucosaminidase (NAG), beta 2-microglobulin (BMG), and microalbumin in 29 of pediatric patients with IDDM, 15 normal controls, and 83 patients with non-diabetic ketoacidosis. Urinary NAG levels were significantly elevated in the IDDM patients compared with controls. Urinary BMG levels were also elevated in IDDM, however, they were not as prominent as NAG levels. Although urinary microalbumin levels were elevated in the IDDM patients, statistical analysis did not show any significant difference between the IDDM patients and controls. Urinary NAG and BMG concentrations were also increased in patients with non-diabetic ketoacidosis, suggesting a toxic effect of ketone bodies to renal tubular cells. Statistically significant correlations were noted both between urinary NAG and microalbumin and between urinary BMG and microalbumin. These results suggest that, in early phase of IDDM, microalbuminuria is preceded by elevations in urinary NAG and BMG levels, and that keton bodies have deleterious effects on renal tubular cells.