Effect of Acute Infusion of Low‐Molecular‐Weight Polyvinylpyrrolidone on Renal Function

Polyvinylpyrrolidone (PVP) is a linear polymer of 1‐vinyl‐2‐pyrrolidone monomers, used initially as a blood plasma expander and later in the pharmacy, food, beverage, and cosmetic industries. PVP is not readily degraded in the body and is sequestered in monocyte/macrophage systems, and in the kidney. Long‐term administration of PVP‐containing solutions causes PVP storage diseases and renal failure. In clearance experiments we examined the effect of acute i.v. infusion of PVP on renal function. Blood urea nitrogen (BUN), urinary beta‐N‐glucosaminidase (NAG), a lysosomal enzyme involved in the degradation of glycoprotein, and alpha 1‐microglobulin, an indicator of proximal tubule absorption ability, were also measured to determine whether acute PVP infusion causes renal injury. PVP infusion elicited significant diuretic and natriuretic effects and reduced glomerular filtration rate (GFR) by 37%. Urine volume, absolute (ENa) and fractional (FENa) Na+ excretion increased 5.5‐fold, 24‐fold and 51‐fold respectively. A relatively small kaliuretic effect was also observed (EK and FEK increased 0.55‐ and 1.8‐fold, respectively). After 2 h PVP infusion, BUN and NAG had not changed significantly (14.8 vs. 17.9 mg/dl and 0.11 vs. 0.18 mU/min/100g bw, respectively). Alpha 1‐microglobulin excretion increased 12‐fold (1.96 vs. 0.15 ng/min/100g bw), indicating that a large portion of fluid and Na+ loss is due to reduced absorption in the proximal tubule. The 24‐fold increase in ENa and the 12‐fold increase in alpha 1‐microglobulin excretion suggest that fluid and electrolyte absorption were also reduced in other nephron segments. We conclude that acute PVP infusion produces diuretic and natriuretic effects due to the osmotically induced reduction of proximal tubular absorption, but does not cause renal damage.