title: A zebrafish model for uremic toxicity: role of the complement pathway.
abstract: Many organic solutes accumulate in end-stage renal disease (ESRD) and some are poorly removed with urea-based prescriptions for hemodialysis. However, their toxicities have been difficult to assess. We have employed an animal model, the zebrafish embryo, to test the toxicity of uremic serum compared to control. Serum was obtained from stable ESRD patients predialysis or from normal subjects. Zebrafish embryos 24 h postfertilization were exposed to experimental media at a water:human serum ratio of 3:1. Those exposed to serum from uremic subjects had significantly reduced survival at 8 h (19 ± 18 vs. 94 ± 6%, p < 0.05, uremic serum vs. control, respectively). Embryos exposed to serum from ESRD subjects fractionated at 50 kDa showed significantly greater toxicity with the larger molecular weight fraction (83 ± 11 vs. 7 ± 17% survival, p < 0.05, <50 vs. >50 kDa, respectively). Heating serum abrogated its toxicity. EDTA, a potent inhibitor of complement by virtue of calcium chelation, reduced the toxicity of uremic serum compared to untreated uremic serum (96 ± 5 vs. 28 ± 20% survival, p < 0.016, chelated vs. nonchelated serum, respectively). Anti-factor B, a specific inhibitor of the alternative complement pathway, reduced the toxicity of uremic serum, compared to untreated uremic serum (98 ± 6 vs. 3 ± 9% survival, p < 0.016, anti-factor B treated vs. nontreated, respectively). Uremic serum is thus more toxic to zebrafish embryos than normal serum. Furthermore, this toxicity is associated with a fraction of large size, is inactivated by heat, and is reduced by both specific and nonspecific inhibitors of complement activation. Together these data lend support to the hypothesis that at least some uremic toxicities may be mediated by complement.
authors.affiliation: Weill Cornell Medical College, New York, NY.
authors.forename: Nathaniel
authors.initials: N
authors.lastname: Berman
authors.affiliation: Albert Einstein College of Medicine, Bronx, NY.
authors.forename: Melisa
authors.initials: M
authors.lastname: Lectura
authors.affiliation: University of Colorado School of Medicine, Aurora, CO.
authors.forename: Josh
authors.initials: J
authors.lastname: Thurman
authors.affiliation: University of Nebraska Medical Center, Omaha, NE.
authors.forename: James
authors.initials: J
authors.lastname: Reinecke
authors.affiliation: Albert Einstein College of Medicine, Bronx, NY.
authors.forename: Amanda C
authors.initials: AC
authors.lastname: Raff
authors.affiliation: Albert Einstein College of Medicine, Bronx, NY.
authors.forename: Michal L
authors.initials: ML
authors.lastname: Melamed
authors.affiliation: University of Nebraska Medical Center, Omaha, NE.
authors.forename: James
authors.initials: J
authors.lastname: Reinecke
authors.affiliation: Albert Einstein College of Medicine, Bronx, NY.
authors.forename: Zhe
authors.initials: Z
authors.lastname: Quan
authors.affiliation: Weill Cornell Medical College, New York, NY.
authors.forename: Todd
authors.initials: T
authors.lastname: Evans
authors.affiliation: Stanford University School of Medicine and VA Medical Center, Palo Alto, CA.
authors.forename: Timothy W
authors.initials: TW
authors.lastname: Meyer
authors.affiliation: Case Western Reserve University School of Medicine, Cleveland, OH.
authors.forename: Thomas H
authors.initials: TH
authors.lastname: Hostetter
mesh_terms: D000818:Animals; D003170:Complement Pathway, Alternative; D003165:Complement System Proteins / Q000378:metabolism*; D004195:Disease Models, Animal; D004625:Embryo, Nonmammalian / Q000378:metabolism*; D005260:Female; D006801:Humans; D007676:Kidney Failure, Chronic / Q000097:blood*; D008297:Male; D044967:Serum; D014511:Uremia / Q000097:blood*; D015027:Zebrafish
chemical_list: D003165:Complement System Proteins