title: Human adipose-derived stromal cells in a clinically applicable injectable alginate hydrogel: Phenotypic and immunomodulatory evaluation.
abstract: OBJECTIVE
  Clinical trials have documented beneficial effects of mesenchymal stromal cells from bone marrow and adipose tissue (ASCs) as treatment in patients with ischemic heart disease. However, retention of transplanted cells is poor. One potential way to increase cell retention is to inject the cells in an in situ cross-linked alginate hydrogel.
  
  
  METHODS
  ASCs from abdominal human tissue were embedded in alginate hydrogel and alginate hydrogel modified with Arg-Gly-Asp motifs (RGD-alginate) and cultured for 1 week. Cell viability, phenotype, immunogenicity and paracrine activity were determined by confocal microscopy, dendritic cell co-culture, flow cytometry, reverse transcriptase quantitative polymerase chain reaction, Luminex multiplex, and lymphocyte proliferation experiments.
  
  
  RESULTS
  ASCs performed equally well in alginate and RGD-alginate. After 1 week of alginate culture, cell viability was >93%. Mesenchymal markers CD90 and CD29 were reduced compared with International Society for Cellular Therapy criteria. Cells sedimented from the alginates during cultivation regained the typical level of these markers, and trilineage differentiation was performed by standard protocols. Hepatocyte growth factor mRNA was increased in ASCs cultivated in alginates compared with monolayer controls. Alginates and alginates containing ASCs did not induce dendritic cell maturation. ASCs in alginate responded like controls to interferon-gamma stimulation (licensing), and alginate culture increased the ability of ASCs to inhibit lymphocyte proliferation.
  
  
  CONCLUSIONS
  ASCs remain viable in alginates; they transiently change phenotype in alginate hydrogel but regain the phenotype of monolayer controls upon release. Cells maintain their paracrine potential while in alginates; the combination of ASCs and alginate is non-immunogenic and, in fact, immunosuppressive.
authors.affiliation: Cardiology Stem Cell Centre, The Heart Centre, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark. Electronic address: bjarke.follin.larsen@regionh.dk.
authors.forename: Bjarke
authors.initials: B
authors.lastname: Follin
authors.affiliation: Cardiology Stem Cell Centre, The Heart Centre, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark.
authors.forename: Morten
authors.initials: M
authors.lastname: Juhl
authors.affiliation: Regenerative Medicine and Stem Cell Research Center and the Avram and Stella Goldstein-Goren Department of Biotechnology Engineering, Ben-Gurion University of the Negev, Israel.
authors.forename: Smadar
authors.initials: S
authors.lastname: Cohen
authors.affiliation: Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Anders Elm
authors.initials: AE
authors.lastname: Pedersen
authors.affiliation: Bioneer A/S, Hørsholm, Denmark.
authors.forename: Monika
authors.initials: M
authors.lastname: Gad
authors.affiliation: Cardiology Stem Cell Centre, The Heart Centre, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark.
authors.forename: Jens
authors.initials: J
authors.lastname: Kastrup
authors.affiliation: Cardiology Stem Cell Centre, The Heart Centre, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark.
authors.forename: Annette
authors.initials: A
authors.lastname: Ekblond
mesh_terms: D017667:Adipocytes / Q000737:chemistry; D000273:Adipose Tissue / Q000166:cytology*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000464:Alginates / Q000008:administration & dosage* / Q000737:chemistry; D002454:Cell Differentiation; D049109:Cell Proliferation; D002470:Cell Survival; D002478:Cells, Cultured; D018920:Coculture Techniques; D005260:Female; D020723:Glucuronic Acid / Q000008:administration & dosage / Q000737:chemistry; D017228:Hepatocyte Growth Factor / Q000235:genetics / Q000378:metabolism; D006603:Hexuronic Acids / Q000008:administration & dosage / Q000737:chemistry; D006801:Humans; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate / Q000008:administration & dosage* / Q000737:chemistry; D056747:Immunomodulation; D007371:Interferon-gamma / Q000378:metabolism; D008297:Male; D045164:Mesenchymal Stem Cell Transplantation / Q000379:methods*; D059630:Mesenchymal Stem Cells / Q000166:cytology; D008875:Middle Aged; D009842:Oligopeptides / Q000737:chemistry; D012333:RNA, Messenger / Q000235:genetics; D016610:Tissue Embedding / Q000379:methods*; D055815:Young Adult
chemical_list: D000464:Alginates; C066855:HGF protein, human; D006603:Hexuronic Acids; D009842:Oligopeptides; D012333:RNA, Messenger; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate; D017228:Hepatocyte Growth Factor; C047981:arginyl-glycyl-aspartic acid; D007371:Interferon-gamma; D020723:Glucuronic Acid
keywords: adipose tissue–derived stromal cells (ASCs); alginate; immunogenicity; immunosuppression; injectable hydrogel; licensing