Urinary prostaglandin D synthase (beta-trace) excretion increases in the early stage of diabetes mellitus

Objective: Circulating levels of lipocalin-type prostaglandin D synthase (L -PGDS)/beta -trace reportedly increase in renal failure as well as in cardi ovascular injuries. We investigated the alterations of L-PGDS in urine and plasma in the early stage of type-2 diabetic patients. Method: Thirty-six t ype-2 diabetic patients and 29 normal subjects were studied. Overnight spot urine and plasma samples were obtained in the morning. L-PGDS was measured by ELISA method using anti-L-PGDS antibody. Variables indicating renal fun ction were determined. Results: Plasma L-PGDS concentration was slightly hi gher in the patients with diabetes mellitus than in the control subjects, w hereas the urinary L-PGDS excretion almost doubled in the diabetic patients as compared with that in the control subjects. Plasma L-PGDS was determine d by plasma creatinine (Cr) concentration while urinary L-PGDS excretion wa s correlated solely with urinary protein excretion. There was no relationsh ip between plasma L-PGDS concentration and urinary L-PGDS excretion. The av eraged plasma concentration of L-PGDS in the diabetics with a normal Cr lev el ill plasma, corresponding to that in the controls, was determined by the plasma Cr concentration. On the other hand, the urinary L-PGDS excretion w as determined by the amount of proteinuria and greater in the diabetics wit h a normal Cr level in plasma than in the controls even when the patients e xhibited urinary protein excretion equal to that in the control subjects. C onclusions: Urinary L-PGDS excretion increased in the early stage of kidney injury in patients with type-2 diabetes mellitus. The urinary excretion wa s correlated independently with urinary protein excretion even when there w as no difference in urinary protein or albumin excretions, thereby suggesti ng that urinary L-PGDS excretion is possibly a more sensitive indicator of renal injuries than proteinuria. Urinary L-PGDS may thus predict the progre ssion of renal injuries in diabetic patients. Copyright (C) 2001 S. Karger AG. Basel.