2000 Fiscal Year Final Research Report Summary
DEVELOPMENT OF RECONSTRUCTIVE SURGERY OF SOFT-TISSUES BY INJECTION OF BASEMENT MEMBRANE
| Project/Area Number |
11694260
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| Research Category |
Grant-in-Aid for Scientific Research (B).
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Plastic surgery
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| Research Institution | NAGOYA UNIVERSITY |
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Principal Investigator |
TORII Shuhei SCHOOL OF MEDICINE, NAGOYA UNIVERSITY, Professor, 医学部, 教授 (60115607)
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| Co-Investigator(Kenkyū-buntansha) |
TORIYAMA Kazuhiro SCHOOL OF MEDICINE, NAGOYA UNIVERSITY, Assistant Professor, 医学部, 講師 (40314017)
KAMEI Yuzuru SCHOOL OF MEDICINE, NAGOYA UNIVERSITY, Associate Professor, 医学部, 助教授 (10257678)
KITAGAWA Yasuo BIO SCIENCE CENTER, NAGOYA UNIVERSITY Professor, 大学院・生命農学研究科, 教授 (50101168)
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| Project Period (FY) |
1999 – 2000
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| Keywords | soft-tissues / adipose tissues / mesenchymal stem cells / basement membrane / capillary / Matrigel / hypoxia / type IV collagen |
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| Research Abstract |
Subcutaneous injection of reconstituted basement membrane (Matrigel) in combination with basic fibroblast growth factor induces de novo adipogenesis in which endogenous precursor cells invade the artificially formed Matrigel space, proliferate and differentiate to form adipose tissue. Since this adipogenesis offers us a novel approach for soft-tissue reconstruction without transplanting preadipocytes, the early process was examined by optical and electron microscopy. Formation of multiple layers of fibroblast-like cells at the surface of Matrigel implant was the first response of connective tissue. The cells within four to five layers proximal to Matrigel implant acquired a thick cytoplasm and an enlarged nucleus, and they invaded Matrigel space together with endothelial cells which caused neovascularization. Phagocytotic incorporation and digestion of Matrigel components by well-developed lysosomes appeared to be a stimulus of fibroblast-like cells to mature depending on proximity to Matrigel. The fibroblast-like cells often contacted to the outer surface of capillary over a large area with a distance of 0.2 to 0.5μm and rapidly accumulated lipid droplets. Electron microscopy of the developing adipocytes showed an well-organized smooth endoplasmic reticulum and mitochondria. This investigation thus revealed the characteristics of adipocyte precursor cells, which can be recruited for regenerative engineering of soft-tissues.
As an experimental model for the hypoxic modulation of collagen metabolism in peripheral tissues, we also cultured 3T3-L1 fibroblasts under low partial oxygen pressure and found that hypoxia enhances secretion of type IV collagen 10-fold and accelerates adipose conversion of the cells. The enhanced secretion of type IV collagen was not accompanied by appreciable increase of α1(IV) and α2(IV) mRNAs. Prolyl 4-hydroxylase α increased only 3-fold under hypoxia.
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