S. K. Odorico1, L. Zitur1, T. Zens1, P. Chlebeck1, J. Danobeitia1, A. D’Alessandro1, L. Fernandez1 1University Of Wisconsin,Department Of Surgery, Division Of Transplantation,Madison, WI, USA
Introduction: Brain dead (BD) kidney grafts in transplantation (TX) fail at higher rates than living donors; innate inflammation is well documented during BD but little is known about coagulation, fibrinolysis and contact regulation, which occurs in conjunction with the innate immune response.
Methods: Our group investigated the dynamics of these upstream inflammatory cascades through a 20-hour (20H) non-human primate (NHP) model of BD and kidney TX that mimics a clinical setting with three treatment groups: vehicle-treated BD (VTBD), sham surgery control and naïve. Analytes of the three pathways were measured via ELISA. Sham (N=4) and VTBD (N=7) protein measurements were compared within and between groups and correlated with outcomes. Gene expression microarrays of kidney biopsies were completed for sham (N=8), VTBD (N=8) and naïve (N=6) groups following the 20H BD period.
Results: CONTACT: An inflammatory state resulted from inducing BD. Factor XII (FXII) and bradykinin (BK), two pro-inflammatory analytes, were up-regulated at both 12H and 20H in VTBD (FXII: p=0.0842 and 0.0419; BK: p=0.0642 and 0.0903) compared to baseline (BL). BK increased 117.2% from BL at 20H in VTBD. Neither prekallikrein nor plasma kallikrein was significantly affected, and this cascade lacked significant differentiation between VTBD and sham. COAGULATION: Thrombin (p=0.0103), fibrinogen (p=0.0134) and vWF (p=0.0005) were all significantly upregulated following the 20H BD period compared to BL in VTBD. However, only thrombin (p=0.0753) increased in VTBD compared to sham. In VTBD, increased fibrinogen was correlated with increased day four serum creatinine (R2=692, p=0.0381). FIBRINOLYSIS: We observed a statistically significant increase in plasminogen (p=0.0002), tissue plasminogen activator (tPA) (p=0.0153) and tPA activity (p=0.0148) following the 20H BD period in VTBD compared to BL. Only plasminogen increased significantly in VTBD compared to sham (12H: p=0.0165, 20H: p=0.0038). MICROARRAY: VTBD genetic profiles lacked contact, coagulation and fibrinolysis activation compared to naïve animals. Interestingly, VTBD had a 14-fold macrophage activation (p<0.05) compared to naïve. Activation of other immune cell types did not occur. Additionally, platelet degranulation (10-fold enrichment, p<0.001) and associated-gene activation (13 genes, p<0.05) occurred in VTBD. Lastly, a down-regulation in metabolic processes in VTBD compared to naïve occurred. However, no clear clustering of genes between sham, naïve and VTBD was observed.
Conclusion: Protein and genetic analysis of contact, coagulation and fibrinolytic pathways portrayed a moderate inflammatory state building throughout the 20H BD period with minor differences between VTBD and sham. In addition, our results indicate an activation of macrophages and platelets, dictating further investigation into the potential roles these innate inflammatory cells play during BD in kidney TX.