title: Ex vivo organ culture of adipose tissue for in situ mobilization of adipose-derived stem cells and defining the stem cell niche.
abstract: In spite of the advances in the knowledge of adipose-derived stem cells (ASCs), in situ location of ASCs and the niche component of adipose tissue (AT) remain controversial due to the lack of an appropriate culture system. Here we describe a fibrin matrix-supported three-dimensional (3D) organ culture system for AT which sustains the ASC niche and allows for in situ mobilization and expansion of ASCs in vitro. AT fragments were completely encapsulated within the fibrin matrix and cultured under dynamic condition. The use of organ culture of AT resulted in a robust outgrowth and proliferation in the fibrin matrix. The outgrown cells were successfully recovered from fibrin by urokinase treatment. These outgrown cells fulfilled the criteria of mesenchymal stem cells, adherence to plastic, multilineage differentiation, and cell surface molecule expression. In vitro label retaining assay revealed that newly divided cells during the culture resided in interstitium between adipocytes and capillary endothelial cells. These interstitial stromal cells proliferated and outgrew into the fibrin matrix. Both in situ mobilized and outgrown cells expressed CD146 and alpha-smooth muscle actin (SMA), but no endothelial cell markers (CD31 and CD34). The structural integrity and spatial approximation of CD31(-)/CD34(-)/CD146(+)/SMA(+) interstitial stromal cells, adipocytes, and capillary endothelial cells were well preserved during in vitro culture. Our results suggest that ASCs are natively associated with the capillary wall and more specifically, belong to a subset of pericytes. Furthermore, organ culture of AT within a fibrin matrix-supported 3D environment can recapitulate the ASC niche in vitro.
authors.affiliation: Deptartment of Pathology, Inje University School of Medicine, Busan, Republic of Korea.
authors.forename: Young-Il
authors.initials: YI
authors.lastname: Yang
authors.forename: Hyeong-In
authors.initials: HI
authors.lastname: Kim
authors.forename: Min-Young
authors.initials: MY
authors.lastname: Choi
authors.forename: Sung-Hee
authors.initials: SH
authors.lastname: Son
authors.forename: Min-Jeong
authors.initials: MJ
authors.lastname: Seo
authors.forename: Ji-Yeon
authors.initials: JY
authors.lastname: Seo
authors.forename: Won-Hee
authors.initials: WH
authors.lastname: Jang
authors.forename: Young-Chul
authors.initials: YC
authors.lastname: Youn
authors.forename: Kang-Joo
authors.initials: KJ
authors.lastname: Choi
authors.forename: Soon-Ho
authors.initials: SH
authors.lastname: Cheong
authors.forename: Jane
authors.initials: J
authors.lastname: Shelby
mesh_terms: D000273:Adipose Tissue / Q000166:cytology*; D000328:Adult; D015415:Biomarkers / Q000378:metabolism; D002454:Cell Differentiation / Q000502:physiology; D049109:Cell Proliferation; D002478:Cells, Cultured; D005337:Fibrin / Q000378:metabolism; D006801:Humans; D008875:Middle Aged; D009924:Organ Culture Techniques / Q000379:methods*; D010641:Phenotype; D055153:Stem Cell Niche; D013234:Stem Cells / Q000166:cytology / Q000502:physiology*; D017154:Stromal Cells / Q000166:cytology / Q000502:physiology; D054457:Tissue Scaffolds
chemical_list: D015415:Biomarkers; D005337:Fibrin