No abstract

Autografting of fat pads has a long history in plastic and reconstructive surgery for augmentation of lost soft tissue. However, the results are disappointing because of absorption of the grafts with time. The fate of transplanted fat is linked to adipose precursor cells distributed widely in connective tissues. Adipocyte precursor cells can proliferate and mature into adipocytes even in the adult body depending on microenvironment. When reconstituted basement membrane, Matrigel, supplemented with more than 1 ng͞ml bFGF was injected s.c. into 6-week-old mice, the neovascularization induced within 1 week was followed by migration of endogenous adipose precursor cells, and a clearly visible fat pad was formed. The pad grew until 3 weeks after the injection and persisted for at least 10 weeks. Such de novo adipogenesis was induced reproducibly by s.c. injection of Matrigel and bFGF over the chest, lateral abdomen, or head. Adipogenesis could be induced even in ear cartilage or in muscle. Thus, our results demonstrated that an abundant population of adipose precursor cells is distributed widely in connective tissues of the adult body and that they migrate into the neovascularized plug of Matrigel for proliferation and maturation. These results suggest a technique of augmenting lost soft tissue in plastic and reconstructive surgery.

No abstract

Midkine (MK) is a retinoic acid-inducible heparin-binding cytokine. In the inflammatory synovitis of rheumatoid arthritis and osteoarthritis, MK was detected in synovial fluid, synoviocytes, and endothelial cells of new blood vessels. Normal synovial fluid and noninflammatory synovial tissue did not contain detectable MK. Therefore, MK showed inflammation-associated expression in these cases. Furthermore, MK was found to promote chemotaxis of neutrophils in the range of 10 ng/ml. The mode of action of MK was found to be haptotactic; the substrate-bound form of MK was the active one. MK is also known to promote fibrinolysis. These activities of MK are in agreement with the modes of MK expression in various pathological statuses, and thus MK is proposed to be an important molecule regulating inflammatory responses.