Document Detail

In vivo repopulation of xenogeneic and allogeneic acellular valve matrix conduits in the pulmonary circulation.
MedLine Citation:
PMID:  12735562     Owner:  NLM     Status:  MEDLINE    
BACKGROUND: Approaches to in vivo repopulation of acellularized valve matrix constructs have been described recently. However, early calcification of acellularized matrices repopulated in vivo remains a major obstacle. We hypothesised that the matrix composition has a significant influence on the onset of early calcification. Therefore, we evaluated the calcification of acellularized allogenic ovine (AVMC) and xenogenic porcine (XVMC) valve matrix conduits in the pulmonary circulation in a sheep model. METHODS: Porcine (n = 3) and sheep (n = 3) pulmonary valve conduits were acellularized by trypsin/EDTA digestion and then implanted into healthy sheep in pulmonary valve position using extracorporeal bypass support. Transthoracic echocardiography (TTE) was performed at 12 and 24 weeks after the implantation. The animals were sacrificed at week 24 or earlier when severe calcification of the valve conduit became evident by TTE. The valves were examined histologically and biochemically. RESULTS: All AVMC revealed severe calcification after 12 weeks with focal endothelial cell clustering and no interstitial valve tissue reconstitution. In contrast, after 24 weeks XVMC indicated mild calcification on histologic examination (von Kossa staining) with histologic reconstitution of valve tissue and confluent endothelial surface coverage. Furthermore, immunohistologic analysis revealed reconstitution of surface endothelial cell monolayer (von Willebrand factor), and interstitial myofibroblasts (Vimentin/Desmin). CONCLUSIONS: Porcine acellularized XVMC are resistant to early calcification during in vivo reseeding. Furthermore, XVMC are repopulated in vivo with valve-specific cell types within 24 weeks resembling native valve tissue.
Rainer G Leyh; Mathias Wilhelmi; Philip Rebe; Stefan Fischer; Theo Kofidis; Axel Haverich; Heike Mertsching
Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  The Annals of thoracic surgery     Volume:  75     ISSN:  0003-4975     ISO Abbreviation:  Ann. Thorac. Surg.     Publication Date:  2003 May 
Date Detail:
Created Date:  2003-05-08     Completed Date:  2003-05-22     Revised Date:  2003-11-14    
Medline Journal Info:
Nlm Unique ID:  15030100R     Medline TA:  Ann Thorac Surg     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1457-63; discussion 1463     Citation Subset:  AIM; IM    
Division of Thoracic and Cardiovascular Surgery, Hannover Medical School, Hannover, Germany.
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MeSH Terms
Calcinosis / etiology,  pathology,  ultrasonography
Echocardiography, Doppler, Color
Endothelium / pathology
Fibroblasts / pathology
Heart Valve Prosthesis* / adverse effects
Heart Valve Prosthesis Implantation*
Intermediate Filament Proteins / analysis
Myocardium / pathology
Pulmonary Valve / pathology*,  surgery*,  ultrasonography
Tissue Engineering*
von Willebrand Factor / analysis
Reg. No./Substance:
0/Intermediate Filament Proteins; 0/von Willebrand Factor

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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