COMPLICATIONS - INFECTIONS

T. Kawahara¹, L.F.S. Lisboa², D.N. Douglas¹, M. Mengel³, J. Lewis¹, A. Humar², N.M. Kneteman^1
1Department Of Surgery, University of Alberta, Edmonton/AB/CANADA, ²Transplant Infectious Diseases, University of Alberta, Edmonton/AB/CANADA, ³Department Of Laboratory Medicine And Pathology, University of Alberta, Edmonton/AB/CANADA

Body: <Introduction> Cytomegalovirus (CMV) is a common viral pathogen that influences the outcome oforgan transplantation. However, there is no established method to evaluate the effects of human CMV (HCMV) treatments in vivo except for human clinical trials. In the current study, we describe thedevelopment of a mouse model that supports the in vivo propagation of HCMV. In this model, HCMV established infection in the humanized livers of severe combined immunodeficient (SCID) mice that havetargeted expression of urokinase type plasminogen activator (uPA) to murine liver regulated by the murine albumin (Alb) promoter (SCID/Alb-uPA mice). <Materials and methods> Hepatocytes were isolated from human livers by collagenase perfusion and purified on a Percol density gradient. One million viable human hepatocytes were injected into the inferior pole of the spleen of recipient SCID/Alb-uPA mice (5-14 day-old). We selected SCID/Alb-uPA recipients with high engraftment of human hepatocytes at 6 weeks post transplantation. Mice having high levels of human hepatocyte engraftment were inoculated with HCMV derived from patient sera. Non-transplanted mice served as controls. Serum was sampled from mice for routine monitoring of HCMV titres and in some cases, mice having established HCMV titres were administered Gancyclovir (50mg/kg/day, ip) beginning at 2 days post HCMV inoculation and daily thereafter until sacrifice. <Results and conclusions> All human liver chimeric mice in this study had high human alpha-1 antitrypsin (hAAT), indicating the presence and activity of functional human hepatocytes (level of human chimerism). Chimeric mice that received HCMV showed high serum titers of HCMV-DNA on day 1 post-inoculation that resolved by day 14 post-inoculation. By contrast, serum from non-transplanted mice had no detectable levels of HCMV-DNA at any of the post-inoculation time points testsed. The levels of HCMV-DNA were sensitive to Gancyclovir treatment since reduced viral titres were observed after 4 days of Gancyclovir administration (by day 6 post inoculation). By contrast, HCMV infected chimeric mice that were not administered GCV sustained viremia over the course of the treatment period. In conclusion, SCID/Alb-uPA mice provide an in vivo setting for the evaluation of treatments for acute HCMV infection. Further studies are required to determine the nature of the acute-resolving course of HCMV infection seen in this animal model.

Disclosure: All authors have declared no conflicts of interest.