Increased Levels of Anaphylatoxin (C5a) and Bradykinin in End-Stage Renal Disease Patients on Maintenance Hemodialysis. Potential Relevance to Heparin Mediated Hemodynamic Responses

Besides the upregulation of inflammatory mediators, end stage renal disease (ESRD) patients maintained on hemodialysis are subjected to periodic exposure to heparin and contact activation due to procedural settings. Recently the presence of a heparin contaminant, namely hypersulfated chondroitin sulfate was linked with the adverse reactions and deaths observed in these patients (Kishmoto, et al. N J Med 2008). To validate this report we measured both the C5a anaphlatoxin and bradykinin levels in ESRD patients prior to and after maintenance hemodialysis. The control group comprised of 40 normal healthy individuals were included to establish the normal level of these mediators. A sandwich ELISA method utilizing a monoclonal antibody which is specific for human C5a and bradykinin were used in these studies. Both the C5a and bradykinin were elevated in pre-dialysis samples from ESRD patients (C5a: 3.2±0.6 ng/ml vs 14.2± 4.6 ng/ml, bradykinin: 6.4±1.8 ng/ml vs 9.3±2.4 ng/ml). Moreover, dialysis itself produced an increase in both the C5a and bradykinin levels. Moreover, the postdialysis samples were further increased, suggesting that dialysis and heparinization itself result in the up-regulation of these mediators. Supplementation of heparin to the plasma also resulted in the generation of both C5a and bradykinin. The plasma samples included in these studies represents patients who were not treateded with the contaminant heparin. Additional studies on in-vitro generation of these markers with contaminated heparin and the isolated contaminant showed that both of these triggered the generation of C5a and bradyknin. These results suggest that both C5a and bradykinin are up-regulated in ESRD patients and this level can be further augmented by dialysis and heparinization. Therefore, additional factors may have contributed to the complex adverse reaction profiles and deaths in patients administrated with contaminated heparin.