title: In vivo differentiation of undifferentiated human adipose tissue-derived mesenchymal stem cells in critical-sized calvarial bone defects.
abstract: Adult stem cells have recently drawn considerable attention for potential cell therapy applications. However, critical details about their specific in vivo environments and cellular activities are unclear. Adipose tissue-derived mesenchymal stem cells (ASCs) are attractive candidates for treating bone defects, but most studies focus on delivery of in vitro-differentiated cells. We assessed various scaffolding materials for the ability to support osteogenic differentiation of undifferentiated human ASCs in vivo, in athymic nude rat calvaria. Twenty-four 9- to 10-week-old athymic nude Sprague-Dawley rats (250 g) were used in these experiments. Fat tissue from 3 patients was harvested from abdominal tissue discarded during reconstructive breast surgery by transverse rectus abdominis myocutaneous flap, performed at the Asan Medical Center after resection of breast cancer. Human ASCs were extracted from discarded adipose tissue and isolated based on standard International Society for Cellular Therapy protocols. Adipose tissue-derived mesenchymal stem cells were seeded on polylactic glycolic acid, atelocollagen, and hydroxyapatite scaffolds, and osteogenesis was evaluated using bone mineral densitometry, histology, immunohistochemistry, and reverse transcription polymerase chain reaction. The gross appearance of scaffolds seeded with ASCs was strikingly different from that of scaffolds alone. Bone mineral densitometry analysis revealed a 2- to 3-fold increase in mineral density in ASC-seeded scaffolds. In addition, undifferentiated ASCs seeded onto hydroxyapatite scaffolds, but not onto collagen or polylactic glycolic acid scaffolds, expressed human messenger RNA for osteogenic markers such as alkaline phosphatase, osteopontin, osteocalcin, and osteonectin. These results indicate that undifferentiated human ASCs can differentiate into osteocytes or osteoblasts in athymic nude rat calvaria, and the importance of appropriate scaffolding for in vivo ASC differentiation.
authors.affiliation: From the *Department of Plastic and Reconstructive Surgery, University of Ulsan College of Medicine, Seoul Asan Medical Center; and †Department of Biomedical Engineering, Hanyang University, Seoul, Korea.
authors.forename: Jong Woo
authors.initials: JW
authors.lastname: Choi
authors.forename: Eun Jung
authors.initials: EJ
authors.lastname: Park
authors.forename: Heung Soo
authors.initials: HS
authors.lastname: Shin
authors.forename: Il Seob
authors.initials: IS
authors.lastname: Shin
authors.forename: Jung Chan
authors.initials: JC
authors.lastname: Ra
authors.forename: Kyung Suk
authors.initials: KS
authors.lastname: Koh
mesh_terms: D000328:Adult; D053687:Adult Stem Cells / Q000166:cytology*; D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D015519:Bone Density; D001861:Bone Regeneration / Q000502:physiology*; D002454:Cell Differentiation; D048091:Guided Tissue Regeneration / Q000379:methods*; D006801:Humans; D059630:Mesenchymal Stem Cells / Q000166:cytology*; D010006:Osteoblasts / Q000166:cytology; D010011:Osteocytes / Q000166:cytology; D010012:Osteogenesis / Q000502:physiology; D051381:Rats; D011923:Rats, Nude; D017207:Rats, Sprague-Dawley; D012886:Skull / Q000293:injuries* / Q000473:pathology / Q000502:physiology; D050507:Subcutaneous Fat, Abdominal / Q000166:cytology*; D054457:Tissue Scaffolds
chemical_list: D015415:Biomarkers