The plasma
pentosidine levels in patients with renal disease were measured by a simple method which was established for plasma and urinary
pentosidine determinations. The method, which can be completed within a few hours, involves pretreating plasma with
proteolytic enzyme (
pronase) and measuring the concentration of
pentosidine in the sample by ELISA using antipentosidine
antibodies. The prepared
antibodies showed no cross-reaction with the raw materials for
pentosidine synthesis or with compounds having similar structures. SDS-PAGE indicated that the
antibodies had a high purity. The reaction of the
antibodies and
keyhole limpet hemocyanin-
pentosidine in the competitive ELISA system was inhibited by free
pentosidine. Excellent standard curves for
pentosidine determination were obtained. In actual measurements of clinical samples from patients, a good correlation (r = 0.9356) was obtained between the values measured by ELISA and HPLC. The plasma
pentosidine level in patients with renal disease correlated significantly with plasma
creatinine,
urea nitrogen, beta2-microglobulin, and
creatinine clearance, indicating its usefulness in evaluating the severity of renal disease. A significant elevation in plasma
pentosidine levels was observed in mild renal dysfunction, whereas no significant increases in
creatinine and
urea nitrogen levels were detected, suggesting that the plasma
pentosidine level is useful in the early diagnosis of beginning
renal failure. In patients with
chronic renal failure, no difference in plasma
pentosidine levels was observed between
diabetic nephropathy and chronic
glomerulonephritis, while a significant correlation was observed with
phosphatidylcholine hydroperoxide, suggesting the possibility that the plasma
pentosidine level reflects injury due to oxidation. From these results, the quantitative measurement method developed by us is judged to be a superior innovation for measuring
pentosidine in body fluids. The plasma
pentosidine level may be useful for the early diagnosis of mild
renal failure and to estimate the degree of the severity of renal diseases.