PLASMA FLUORESCEIN BINDING AND TRANSCAPILLARY FLUORESCEIN ESCAPE RATEIN RENAL-FAILURE ASSOCIATED WITH DIABETES

Microvascular damage, often resulting in renal failure, is a common co mplication of diabetes. Transcapillary fluorescein escape rate (TCFER) as monitored by intravital microscopy has been used as an indicator o f the extent of capillary damage in diabetes and to assess improvement in microvascular function after combined kidney-pancreas transplant. However, fluorescein anion binds to plasma albumin, and albumin-ligand binding may be altered in the presence of renal disease. The purpose of this study was to compare fluorescein binding by plasma from diabet ics with renal failure with plasma from healthy nondiabetics. Fluoresc ein binding by plasma from seven type I diabetics awaiting kidney-panc reas transplant and seven healthy adults of similar age and sex was st udied using ultrafiltration and dialysis. There was no significant dif ference in the apparent albumin binding of fluorescein at physiologica lly relevant fluorescein concentrations, even though the TCFER was sig nificantly increased in the diabetics as compared with the controls. H ippurate, a ligand that accumulates in renal failure, did alter fluore scein binding in a defatted albumin solution but not sufficiently to a ccount for the differences in TCFERs. These data indicate that impaire d albumin binding of fluorescein does not contribute significantly to the TCFER in diabetics with renal failure. (C) 1995 by the National Ki dney Foundation, Inc.