CALCIFICATION OF SUBCUTANEOUSLY IMPLANTED COLLAGENS IN RELATION TO CYTOTOXICITY, CELLULAR INTERACTIONS AND CROSS-LINKING

In general, calcification of biomaterials occurs through an interactio n of host and implanted material factors, but up to now the real origi n of pathologic calcification is unknown. In this study we aimed to in vestigate incidence of calcification of (crosslinked) dermal sheep col lagens (DSCs) with respect to their specific properties, during subcut aneous implantation in rats. Three types of DSCs were commercially obt ained: non-crosslinked DSC (NDSC), and DSC crosslinked with glutaralde hyde (GDSC) and hexamethylenediisocyanate (HDSC). NDSC, HDSC and GDSC were (enzymatically) tissue culture pretreated to eliminate their cyto toxic products. Beside this, crosslinking methods were modified to opt imize mechanical properties and to decrease cytotoxicity, which result ed in HDSC and GDSC*. Furthermore, DSC was crosslinked by activation of the carboxylic groups, i.e. by means of acyl azide and carbodiimide , resulting in AaDSC and CDSC, respectively. After implantation of HDS Cs and GDSCs a relation between cytotoxicity and calcification of cros slinked DSC could be made. No relation was found between cellular infi ltration of DSCs and calcification. However, from the use of different types and modification of crosslinking methods it might be concluded that calcification is mainly related to stable crosslinks, i.e. to the chemical properties of the obtained material.