title: Effects of periodate and chondroitin 4-sulfate on proteoglycan stabilization of ostrich pericardium. Inhibition of calcification in subcutaneous implants in rats.
abstract: Chemical modification of biological materials used in the manufacture of cardiac valves tends to reduce the relatively high degree of biodegradation and calcification of the implanted bioprostheses. The most widely used treatment to reduce biodegradability of the valves is glutaraldehyde fixation. However, this treatment is potentially toxic and induces tissue calcification. In order to minimize these undesirable effects, we have analyzed the effect of a pre-fixation of endogenous proteoglycans and exogenous glycosaminoglycans, as well as the borohydride reduction influence on the different modified ostrich pericardium implants after subcutaneous implantation in rats. The presence of calcific deposits was detected in all implanted GA-fixed samples; however, calcification was highly reduced in both groups of periodate-prefixed materials, which showed also a very low Ca/P molar ratio. Borohydride post-treatment of these biomaterials resulted in a significant increase in calcium phosphate precipitation, with the appearance of calcium deposits mainly in an amorphous form even though X-ray diffraction allowed the detection of brushite- and apatite-like crystals. Regarding tissue stability, no significant differences were found among the borohydride-untreated implants but higher levels of matrix metalloproteinases were observed by gelatin zymography in the periodate pre-fixed materials. This increase was partially reduced by pre-fixation of exogenous chondroitin 4-sulfate. On the other hand, borohydride post-treatment not only increased calcification, but also reduced tissue stability and increased the presence of matrix-degrading activities.
authors.affiliation: Servicio de Cirugía Experimental, Unidad de Biomateriales, Clínica Puerta de Hierro, San Martín de Porres 4, Madrid 28035, Spain.
authors.forename: Beatriz
authors.initials: B
authors.lastname: Arenaz
authors.forename: Marian Martín
authors.initials: MM
authors.lastname: Maestro
authors.forename: Pilar
authors.initials: P
authors.lastname: Fernández
authors.forename: Javier
authors.initials: J
authors.lastname: Turnay
authors.forename: Nieves
authors.initials: N
authors.lastname: Olmo
authors.forename: Jesús
authors.initials: J
authors.lastname: Senén
authors.forename: Javier Gil
authors.initials: JG
authors.lastname: Mur
authors.forename: María Antonia
authors.initials: MA
authors.lastname: Lizarbe
authors.forename: Eduardo
authors.initials: E
authors.lastname: Jorge-Herrero
mesh_terms: D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry; D001705:Bioprosthesis / Q000009:adverse effects*; D002114:Calcinosis / Q000209:etiology / Q000517:prevention & control*; D002809:Chondroitin Sulfates / Q000737:chemistry / Q000494:pharmacology*; D006084:Graft Rejection / Q000150:complications / Q000517:prevention & control; D066298:In Vitro Techniques; D008422:Materials Testing; D010496:Pericardium / Q000187:drug effects / Q000378:metabolism* / Q000637:transplantation*; D010504:Periodic Acid / Q000494:pharmacology*; D011475:Prosthesis Failure; D011509:Proteoglycans / Q000737:chemistry / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D020310:Struthioniformes; D016707:Tissue Fixation / Q000379:methods
chemical_list: D001672:Biocompatible Materials; D011509:Proteoglycans; D010504:Periodic Acid; D002809:Chondroitin Sulfates; C009288:metaperiodate