Decellularized pig pulmonary heart valves-Depletion of nucleic acids measured by proviral PERV pol.

BACKGROUND: Decellularized human pulmonary heart valve (dhHV) scaffolds have been shown to be the gold standard especially for younger, adolescent patients. However, human heart valves are limited in availability. Xenogeneic decellularized pig heart valves (dpHV) may serve as alternative. METHODS: The efficacy of DNA reduction processes upon decellularization of heart valves from German Landrace pigs was analyzed by measurements of remaining nucleic acids including proviral porcine endogenous retrovirus (PERV) sequences. Porcine pulmonary heart valves (pPHV) were decellularized by three different protocols and further treated with DNaseI or Benzonase, at varying incubation times. DNA isolated from valve associated muscle (m), valve cusp (c), and pulmonary artery (pa) was monitored by PCR and qRT-PCR using GAPDH and the PERV polymerase (pol) for read-out. RESULTS: Decellularization of pPHV led to a significant reduction of DNA (>99%) which could be further significantly increased for (m) and (pa) by nuclease treatment, reducing proviral PERV pol from approximately 5 × 107 to 5 × 103  copies/mg in nuclease treated tissues. CONCLUSIONS: Both nucleases demonstrated comparable activities. But DNaseI revealed to be less consistent for PERV, especially at muscular tissue. Noteworthy, remaining proviral sequences are still detectable by PCR; however, due to the absence of the cellular replication machinery the production of infectious particles is not expected. Decellularization and nuclease treatment of pPHV is an efficient procedure to reduce the DNA content including PERV, thus represents a valuable option to increase virus safety independently from the source animal background.

Enteroviral infection of a cardiac prosthetic device.

BACKGROUND: Identification of the causative pathogen may be challenging in culture negative infective endocarditis (IE). METHODS: A 4 month-old 21-trisomic boy with congenital atrioventricular septal defect presented 3 episodes of dehiscence of his prosthetic patch, attributed to IE. He presented heart failure, but neither fever, nor inflammatory syndrome. RESULTS: Surgical and histopathological findings confirmed the diagnosis of IE, but blood cultures remained sterile. Extensive work up failed to demonstrate bacterial or fungal etiology. Coxsackie B2 virus was cultured from the excised patch, nasopharyngeal secretions and stools. CONCLUSIONS: Viral IE has only been described in animal models. This case is the first reported probable human viral IE. We suggest that a viral etiology should be considered in case of culture negative IE.

Frequent detection of viral nucleic acids in heart valve tissue.

Due to a paucity of published data concerning the prevalence of viral nucleic acid in homografts, we analyzed tissue from 30 donor hearts for the presence of viral genome sequences of enteroviruses, adenoviruses, human cytomegalovirus, and influenza virus using different PCR techniques. Viral DNA was amplified in 64 and 52% of the subvalvular myocardial tissue and non-coronary valve samples, respectively. These findings, compared with clinical history and histologic and serologic analysis, demonstrate the importance of viral safety measures in heart valve banking.

Heart valves from pigs and the porcine endogenous retrovirus: experimental and clinical data to assess the probability of porcine endogenous retrovirus infection in human subjects.

OBJECTIVE: Replacement of heart valves in human subjects has become a routine procedure in cardiac operations. We sought to investigate whether commercially available glutaraldehyde-fixed porcine heart valve prostheses cause porcine endogenous retrovirus infection in human subjects because recent studies revealed that human cells can be infected with porcine endogenous retrovirus. METHODS: Blood samples of 18 patients who underwent aortic or mitral valve replacement with porcine heart valves were collected 6 months to 3 years after operation and tested for porcine endogenous retrovirus by means of polymerase chain reaction and reverse transcriptase-polymerase chain reaction. In addition, we tried to trace porcine endogenous retrovirus in 3 commercially available, glutaraldehyde-fixed, porcine heart valves. RESULTS: Porcine endogenous retrovirus can be easily detected in native porcine heart valves and degrades completely within 1 week of fixation in glutaraldehyde. In all 3 commercially available porcine heart valves, no traces of porcine endogenous retrovirus were found. All blood samples showed negative test results for the porcine endogenous retrovirus genome. CONCLUSION: Our results indicate that glutaraldehyde fixation of porcine heart valves reliably prevents cross-species transmission of porcine endogenous retrovirus.