Abstract
Bovine aprotinin, a reversible inhibitor of plasmin and kallikrein, has been clinically approved for over two decades to prevent perioperative blood loss during cardiac surgery. However, because of postoperative renal dysfunction in thousands of these patients, aprotinin was voluntarily withdrawn from the market. Our earlier studies indicated that a R24K mutant of the first Kunitz-type domain of human tissue factor pathway inhibitor-2 (R24K KD1) exhibited plasmin inhibitory activity equivalent to aprotinin in vitro. In this study, we compared the effects on renal function after infusion of aprotinin and recombinant R24K KD1 in chronically instrumented, conscious rats. Aprotinin-infused rats exhibited statistically significant decreases in glomerular filtration rate and effective renal plasma flow relative to rats infused with phosphate-buffered saline (PBS) or R24K KD1 dissolved in PBS. In addition, aprotinin-treated rats exhibited marked increases in serum creatinine, blood urea nitrogen, urinary protein, and effective renal vascular resistance, whereas these renal parameters remained essentially unchanged in vehicle and R24K KD1-treated rats for a one-week period. Moreover, with use of a highly sensitive apoptosis detection assay, a significant increase in the rate of early and late apoptotic events in renal tubule cells occurred in aprotinin-treated rats relative to R24K KD1-treated rats. In addition, histological examination of the rat kidney revealed markedly higher levels of protein reabsorption droplets in the aprotinin-infused rats. Our data collectively provide suggestive evidence that R24K KD1 does not induce the renal dysfunction associated with aprotinin, and may be an effective clinical alternative to aprotinin as an antifibrinolytic agent in cardiac surgery.
Footnotes
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W.K. is a coauthor of U.S. patent 7,432,238 entitled Human Kunitz-type Inhibitor With Enhanced Anti-Fibrinolytic Activity. All other authors have no financial interests.
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This work was supported by the National Institutes of Health [Grant HL64119] (to W.K.).
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Article, publication date, and citation information can be found at http://jpet.aspetjournals.org.
doi:10.1124/jpet.109.161034
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ABBREVIATIONS:
- R24K KD1
- the first Kunitz-type domain of issue factor pathway inhibitor-2–mutated at position 24
- GFR
- glomerular filtration rate
- ERPF
- effective renal plasma flow
- ERVR
- effective renal vascular resistance
- IN
- inulin
- PAH
- p-aminohippurate
- BUN
- blood urea nitrogen
- BW
- body weight.
- Received August 26, 2009.
- Accepted September 22, 2009.
- © 2009 by The American Society for Pharmacology and Experimental Therapeutics
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