Nimni M E, Bernick S, Cheung D T, Ertl D C, Nishimoto S K, Paule W J, Salka C, Strates B S
University of Southern California School of Medicine, Department of Medicine, Los Angeles.
Calcif Tissue Int. 1988 May;42(5):313-20. doi: 10.1007/BF02556366.
Ectopic calcification of diseased tissues or around prosthetic implants can lead to serious disability. Therefore, calcification of implants of glutaraldehyde-cross-linked collagenous tissues and reconstituted collagen was compared with mineralization induced by demineralized bone matrix (DBM). Whereas implants of DBM accumulated large amounts of calcium and a bone-specific gamma-carboxyglutamic acid protein (BGP or osteocalcin) following implantation in both young and older rats, implants of cross-linked pericardium calcified with only traces of BGP. Glutaraldehyde-cross-linked DBM failed to calcify after implantation in 8-month-old rats for 2-16 weeks. Implants of cross-linked type I collagen exhibited small calcific deposits 2 weeks postimplantation but calcium content eventually dropped to levels equal to those of soft tissues as the implants were resorbed. The calcium content of DBM implanted in 1- and 8-month-old rats reached comparable levels after 4 weeks, but the BGP content was approximately twice as high in the younger animals than in the older ones. Glutaraldehyde-cross-linked implants of DBM, tendon, and cartilage calcified significantly in young but not in old animals. This form of dystrophic calcification was associated with only trace amounts of BGP. Alkaline phosphatase activity was high in implants of DBM and undetectable in implants of cross-linked collagenous tissues. These results show that implants of glutaraldehyde-cross-linked collagenous tissues and reconstituted collagen calcify to different extents depending upon their origin and the age of the host, and that the mechanism of dystrophic calcification differs significantly from the process of mineralization associated with bone induction as reflected by alkaline phosphatase activity and BGP accumulation.
患病组织或假体植入物周围的异位钙化可导致严重残疾。因此，对戊二醛交联胶原组织和重组胶原植入物的钙化情况与脱矿骨基质（DBM）诱导的矿化情况进行了比较。在年轻和老年大鼠体内植入后，DBM植入物积累了大量钙和一种骨特异性γ-羧基谷氨酸蛋白（BGP或骨钙素），而交联心包植入物仅出现微量BGP的钙化。戊二醛交联的DBM在8月龄大鼠体内植入2至16周后未发生钙化。交联I型胶原植入物在植入后2周出现少量钙化沉积，但随着植入物被吸收，钙含量最终降至与软组织相当的水平。在1月龄和8月龄大鼠体内植入的DBM，4周后钙含量达到相当水平，但年轻动物体内的BGP含量约为老年动物的两倍。戊二醛交联的DBM、肌腱和软骨植入物在年轻动物体内显著钙化，而在老年动物体内则不然。这种营养不良性钙化形式仅与微量BGP相关。DBM植入物中的碱性磷酸酶活性较高，而交联胶原组织植入物中未检测到该酶活性。这些结果表明，戊二醛交联胶原组织和重组胶原植入物的钙化程度因来源和宿主年龄而异，并且营养不良性钙化机制与碱性磷酸酶活性和BGP积累所反映的骨诱导相关矿化过程有显著差异。
