title: Comparative study of equine mesenchymal stem cells from healthy and injured synovial tissues: an in vitro assessment.
abstract: BACKGROUND
  Bone marrow and adipose tissues are known sources of mesenchymal stem cells (MSCs) in horses; however, synovial tissues might be a promising alternative. The aim of this study was to evaluate phenotypic characteristics and differentiation potential of equine MSCs from synovial fluid (SF) and synovial membrane (SM) of healthy joints (SF-H and SM-H), joints with osteoarthritis (SF-OA and SM-OA) and joints with osteochondritis dissecans (SF-OCD and SM-OCD) to determine the most suitable synovial source for an allogeneic therapy cell bank.
  
  
  METHODS
  Expression of the markers CD90, CD105, CD44, and CD34 in SF-H, SM-H, SF-OA, SM-OA, SF-OCD and SM-OCD was verified by flow cytometry, and expression of cytokeratin, vimentin, PGP 9.5, PCNA, lysozyme, nanog, and Oct4 was verified by immunocytochemistry. MSCs were cultured and evaluated for their chondrogenic, osteogenic and adipogenic differentiation potential. Final quantification of extracellular matrix and mineralized matrix was determined using AxioVision software. A tumorigenicity test was conducted in Balb-C(nu/nu) mice to verify the safety of the MSCs from these sources.
  
  
  RESULTS
  Cultured cells from SF and SM exhibited fibroblastoid morphology and the ability to adhere to plastic. The time elapsed between primary culture and the third passage was approximately 73 days for SF-H, 89 days for SF-OCD, 60 days for SF-OA, 68 days for SM-H, 57 days for SM-OCD and 54 days for SM-OA. The doubling time for SF-OCD was higher than that for other cells at the first passage (P < 0.05). MSCs from synovial tissues showed positive expression of the markers CD90, CD44, lysozyme, PGP 9.5, PCNA and vimentin and were able to differentiate into chondrogenic (21 days) and osteogenic (21 days) lineages, and, although poorly, into adipogenic lineages (14 days). The areas staining positive for extracellular matrix in the SF-H and SM-H groups were larger than those in the SF-OA and SM-OA groups (P < 0.05). The positive mineralized matrix area in the SF-H group was larger than those in all the other groups (P < 0.05). The studied cells exhibited no tumorigenic effects.
  
  
  CONCLUSIONS
  SF and SM are viable sources of equine MSCs. All sources studied provide suitable MSCs for an allogeneic therapy cell bank; nevertheless, MSCs from healthy joints may be preferable for cell banking purposes because they exhibit better chondrogenic differentiation capacity.
authors.affiliation: Department of Internal Medicine, School of Veterinary Medicine and Animal Science, University of São Paulo (USP), Avenida Prof. Orlando Marques de Paiva, 87, 05508-270, São Paulo, SP, Brazil. fulberjoice@yahoo.com.br.
authors.forename: Joice
authors.initials: J
authors.lastname: Fülber
authors.affiliation: Laboratory of Biochemistry and Biophysics, Butantan Institute, Avenida Vital Brasil 1500, São Paulo, 05503-900, SP, Brazil. durvanei.maria@butantan.gov.br.
authors.forename: Durvanei A
authors.initials: DA
authors.lastname: Maria
authors.affiliation: Department of Surgery, School of Veterinary Medicine and Animal Science, University of São Paulo (USP), Avenida Prof. Orlando Marques de Paiva, 87, SP, 05508-270, SP, Brazil. silvalc@usp.br.
authors.forename: Luis Cláudio Lopes Correia
authors.initials: LC
authors.lastname: da Silva
authors.affiliation: Department of Pathology, School of Veterinary Medicine and Animal Science, University of São Paulo (USP), Avenida Prof. Orlando Marques de Paiva, 87, São Paulo, 05508-270, SP, Brazil. cmassoco@gmail.com.
authors.forename: Cristina O
authors.initials: CO
authors.lastname: Massoco
authors.affiliation: Department of Internal Medicine, School of Veterinary Medicine and Animal Science, University of São Paulo (USP), Avenida Prof. Orlando Marques de Paiva, 87, 05508-270, São Paulo, SP, Brazil. fe_nandara@hotmail.com.
authors.forename: Fernanda
authors.initials: F
authors.lastname: Agreste
authors.affiliation: Department of Internal Medicine, School of Veterinary Medicine and Animal Science, University of São Paulo (USP), Avenida Prof. Orlando Marques de Paiva, 87, 05508-270, São Paulo, SP, Brazil. baccarin@usp.br.
authors.forename: Raquel Y Arantes
authors.initials: RY
authors.lastname: Baccarin
mesh_terms: D000818:Animals; D015703:Antigens, CD / Q000378:metabolism; D015197:Carcinogenicity Tests; D002478:Cells, Cultured; D005260:Female; D006734:Horse Diseases / Q000473:pathology* / Q000628:therapy; D006736:Horses; D008297:Male; D045164:Mesenchymal Stem Cell Transplantation; D059630:Mesenchymal Stem Cells / Q000502:physiology*; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D010003:Osteoarthritis / Q000473:pathology / Q000628:therapy / Q000662:veterinary*; D013582:Synovial Fluid
chemical_list: D015703:Antigens, CD