Development of Revolutionizing Biomaterials Substituting Various Mammalian Organs by Means of Sintered Bioceramics

摘要

Development of biomaterials substituting various mammalian organs can be carried out by means of experimental evolutionary studies using collagen-hydroxyapatite composite, derived from adult cattle. The evolution of the tissue-immune system can be studies by commpound-ceramics of collagen-hydroxyapatite composite. Collagen-hydroxyapatite composite was sintered by high-pressure technique using collagen extracted from cattle skin, which had antigenicity. Artifical bone marrow chambers were fabricated with the sintered collagen-hydroxyapatite composite. Experimental evolutionary studies using mammals (dogs) and chondrichthyes (sharks) were carried out implanting the chambers into their muscles. The result showed that around the collagen composed chambers implanted into dorsal muscle of dogs, marked cell differentiation as well as dedifferentiation with atypia could be observed, which resembled a part the digestive tract of intestine histologically. Around the chambers implanted into dorsal muscle of sharks hemopoietic nests could be observed, which were quite similar to those induced by the chambers of conventionally sintered hydroxyapatite. Hemopoiesis and osteoid formation 4 months after surgery were observed around the collagen-apatite chamber implanted in the shark muscle as well as in upper site of vertebral cartilage of the spinal cord. No bone marrow in the cartilaginous tissue in upper site of the spinal cord is evident in control sharks. Xenotransplantation of skin, i.e., skin grafts between sharks of different kinds of species, as well as between sharks and xenopus (amphibian), sharks and mammals (rat) are carried out. All of them are successful and chimera placoids between them are developed. After that, the author successfully carried out xenotransplantatin of various organs of chondrichthyes into those of dogs.