Heart valve collagens: cross-species comparison using immunohistological methods.

BACKGROUND AND AIM OF THE STUDY Tissue engineering is an emerging strategy for the development of replacement heart valves where the properties of native tissues are to be replicated. The complexity of the distribution of various collagens in the aortic, mitral, and pulmonary valve leaflets of porcine, bovine, and ovine origin, has been examined. METHODS Immunohistological and transmission electron microscopy analyses using monoclonal antibodies to types I, III, IV, V and VI collagens were performed. RESULTS The results indicated that each collagen type has its own distinct distribution, with minimal variation between heart valve anatomic sites and species. Of particular interest was type VI collagen, which had an asymmetric distribution that was principally localized along the outflow surface of the valve. CONCLUSION Successful tissue engineering constructs of heart valves may need to replicate the complex distribution of different collagens found in heart valve tissues.