title: Microbiological safety of porcine islets: comparison with source pig.
abstract: BACKGROUND
  Pig islet donors intended for clinical xenotransplantation for the treatment of diabetes must meet stringent conditions. Among others, viruses with the potential to cross the species barrier should be excluded from the herd: this list includes encephalomyocarditis virus (EMCV), hepatitis E virus (HEV), porcine cytomegalovirus (PCMV) and porcine γ-lymphotropic herpesvirus (PLHV). As an islet product is isolated from the pancreas and then subjected to culture before implantation, the question is raised whether islets could be negative even if the animal itself is positive for a distinct pathogen.
  
  
  METHODS
  To answer this question, sensitive quantitative real-time PCR assays were established for EMCV, HEV, PCMV and PLHV. Twelve adult animals from a high-hygienic herd were then evaluated; testing tissues, where the virus is expected to reside in latent infection, testing islets immediately after isolation, and then isolated islets after a 7-day culture.
  
  
  RESULTS
  None of the tissues tested positive for EMCV, HEV or PLHV. PCMV was observed in spleen tissue from six animals: three of these six animals were positive for isolated islets, and two of these three cases were also positive for islets after culture. Older animals in particular showed positivity, and within a given litter not all animals were PCMV positive.
  
  
  CONCLUSIONS
  These data fit with spread through the herd by horizontal transmission, not in utero infection. PCMV has to be excluded from the herd to ensure that islets for transplantation are negative for PCMV.
authors.affiliation: Department of Veterinary & Biomedical Sciences, University of Minnesota, St. Paul, MN 55108, USA.
authors.forename: Juan E
authors.initials: JE
authors.lastname: Abrahante
authors.forename: Kyra
authors.initials: K
authors.lastname: Martins
authors.forename: Klearchos K
authors.initials: KK
authors.lastname: Papas
authors.forename: Bernhard J
authors.initials: BJ
authors.lastname: Hering
authors.forename: Henk-Jan
authors.initials: HJ
authors.lastname: Schuurman
authors.forename: Michael P
authors.initials: MP
authors.lastname: Murtaugh
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D003587:Cytomegalovirus / Q000302:isolation & purification; D003586:Cytomegalovirus Infections / Q000517:prevention & control / Q000635:transmission / Q000662:veterinary; D004686:Encephalomyocarditis virus / Q000302:isolation & purification; D016752:Hepatitis E virus / Q000302:isolation & purification; D006564:Herpesviridae / Q000302:isolation & purification; D007515:Islets of Langerhans / Q000166:cytology / Q000382:microbiology*; D016381:Islets of Langerhans Transplantation / Q000592:standards*; D008297:Male; D016133:Polymerase Chain Reaction; D013552:Swine; D014019:Tissue Donors; D014183:Transplantation, Heterologous / Q000592:standards*; D014777:Virus Diseases / Q000517:prevention & control / Q000635:transmission / Q000662:veterinary*