title: Guided tissue regeneration: porcine matrix does not transmit PERV.
abstract: OBJECTIVE
  For cardiovascular tissue engineering, acellularized scaffolds of porcine matrices have been successfully used. However, the possibility of porcine endogenous retrovirus (PERV) transmission remains debatable. In this study, we investigated whether acellularized porcine vascular scaffolds cause cross-species transmission of PERV in a xenogenic model.
  
  
  METHODS
  Porcine pulmonary arteries were acellularized and implanted into sheep in orthotopic position (n=6). Cardiopulmonary bypass support was used for all operations. Blood samples were collected regularly up to 6 months after the operation, and cellular components were tested for PERV infection by PCR and RT-PCR. Grafts were explanted 6 and 12 months after implantation. Tissue samples were characterized by histology and electron microscopy and tested for PERV sequences.
  
  
  RESULTS
  All animals survived the procedure and follow up until explantation of the grafts. PERV DNA was detectable in acellularized scaffolds of porcine matrices. Acellular porcine pulmonary arteries scaffolds were repopulated in vivo by autologous cells of the host, leading to a vessel consisting of all cellular components of the vessel wall. No PERV sequences were detectable neither in all tested peripheral blood samples nor in tissue samples of in vivo recellularized grafts up to 6 months after implantation. Electron microscopy revealed no signs of graft infection by retrovirus.
  
  
  CONCLUSIONS
  Guided tissue regeneration of acellularized vascular porcine matrix scaffolds leads to structured vessels up to one year without risk of PERV transmisson.
authors.affiliation: Department of Thoracic and Cardiovascular Surgery, Hennover Medical School, Carl-Neuberg-Strasse 1, 30623 Hannover, Germany. kallenbach@thg.mh-hannover.de
authors.forename: Klaus
authors.initials: K
authors.lastname: Kallenbach
authors.forename: Rainer G
authors.initials: RG
authors.lastname: Leyh
authors.forename: Elena
authors.initials: E
authors.lastname: Lefik
authors.forename: Thorsten
authors.initials: T
authors.lastname: Walles
authors.forename: Matthias
authors.initials: M
authors.lastname: Wilhelmi
authors.forename: Serghei
authors.initials: S
authors.lastname: Cebotari
authors.forename: Andreas
authors.initials: A
authors.lastname: Schmiedl
authors.forename: Axel
authors.initials: A
authors.lastname: Haverich
authors.forename: Heike
authors.initials: H
authors.lastname: Mertsching
mesh_terms: D000818:Animals; D021522:Bioartificial Organs / Q000009:adverse effects / Q000821:virology; D020077:Endogenous Retroviruses / Q000302:isolation & purification; D005109:Extracellular Matrix / Q000637:transplantation* / Q000821:virology*; D006084:Graft Rejection / Q000175:diagnosis / Q000209:etiology / Q000821:virology*; D008297:Male; D012038:Regeneration; D012192:Retroviridae Infections / Q000175:diagnosis / Q000635:transmission* / Q000821:virology*; D013552:Swine; D023822:Tissue Engineering / Q000009:adverse effects* / Q000379:methods*; D019737:Transplants / Q000009:adverse effects