title: CD34⁺/M-cadherin⁺ bone marrow progenitor cells promote arteriogenesis in ischemic hindlimbs of ApoE⁻/⁻ mice.
abstract: BACKGROUND
  Cell-based therapy shows promise in treating peripheral arterial disease (PAD); however, the optimal cell type and long-term efficacy are unknown. In this study, we identified a novel subpopulation of adult progenitor cells positive for CD34 and M-cadherin (CD34⁺/M-cad⁺ BMCs) in mouse and human bone marrow. We also examined the long-lasting therapeutic efficacy of mouse CD34⁺/M-cad⁺ BMCs in restoring blood flow and promoting vascularization in an atherosclerotic mouse model of PAD.
  
  
  RESULTS
  Colony-forming cell assays and flow cytometry analysis showed that CD34⁺/M-cad⁺ BMCs have hematopoietic progenitor properties. When delivered intra-arterially into the ischemic hindlimbs of ApoE⁻/⁻ mice, CD34⁺/M-cad⁺ BMCs alleviated ischemia and significantly improved blood flow compared with CD34⁺/M-cad⁻ BMCs, CD34⁻/M-cad⁺ BMCs, or unselected BMCs. Significantly more arterioles were seen in CD34⁺/M-cad⁺ cell-treated limbs than in any other treatment group 60 days after cell therapy. Furthermore, histologic assessment and morphometric analyses of hindlimbs treated with GFP⁺ CD34⁺/M-cad⁺ cells showed that injected cells incorporated into solid tissue structures at 21 days. Confocal microscopic examination of GFP⁺ CD34⁺/M-cad⁺ cell-treated ischemic legs followed by immunostaining indicated the vascular differentiation of CD34⁺/M-cad⁺ progenitor cells. A cytokine antibody array revealed that CD34⁺/M-cad⁺ cell-conditioned medium contained higher levels of cytokines in a unique pattern, including bFGF, CRG-2, EGF, Flt-3 ligand, IGF-1, SDF-1, and VEGFR-3, than did CD34⁺/M-cad⁻ cell-conditioned medium. The proangiogenic cytokines secreted by CD34⁺/M-cad⁺ cells induced oxygen- and nutrient-depleted endothelial cell sprouting significantly better than CD34⁺/M-cad⁻ cells during hypoxia.
  
  
  CONCLUSIONS
  CD34⁺/M-cad⁺ BMCs represent a new progenitor cell type that effectively alleviates hindlimb ischemia in ApoE⁻/⁻ mice by consistently improving blood flow and promoting arteriogenesis. Additionally, CD34⁺/M-cad⁺ BMCs contribute to microvascular remodeling by differentiating into vascular cells and releasing proangiogenic cytokines and growth factors.
authors.affiliation: The Texas Heart Institute at St. Luke's Episcopal Hospital, Houston, Texas, United States of America.
authors.forename: Toya
authors.initials: T
authors.lastname: Terry
authors.forename: Zhiqiang
authors.initials: Z
authors.lastname: Chen
authors.forename: Richard A F
authors.initials: RA
authors.lastname: Dixon
authors.forename: Peter
authors.initials: P
authors.lastname: Vanderslice
authors.forename: Pierre
authors.initials: P
authors.lastname: Zoldhelyi
authors.forename: James T
authors.initials: JT
authors.lastname: Willerson
authors.forename: Qi
authors.initials: Q
authors.lastname: Liu
mesh_terms: D000818:Animals; D018952:Antigens, CD34 / Q000378:metabolism*; D001057:Apolipoproteins E / Q000235:genetics / Q000378:metabolism*; D001854:Bone Marrow Cells / Q000166:cytology / Q000502:physiology*; D015820:Cadherins / Q000235:genetics / Q000378:metabolism*; D002469:Cell Separation; D064987:Cell- and Tissue-Based Therapy / Q000379:methods; D002478:Cells, Cultured; D017077:Culture Media, Conditioned / Q000737:chemistry; D016207:Cytokines / Q000378:metabolism; D005434:Flow Cytometry; D006614:Hindlimb / Q000098:blood supply* / Q000503:physiopathology; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000378:metabolism; D007511:Ischemia / Q000503:physiopathology*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D018919:Neovascularization, Physiologic / Q000502:physiology*; D058729:Peripheral Arterial Disease / Q000473:pathology / Q000503:physiopathology / Q000628:therapy; D012039:Regional Blood Flow; D013234:Stem Cells / Q000166:cytology / Q000502:physiology*
chemical_list: D018952:Antigens, CD34; D001057:Apolipoproteins E; D015820:Cadherins; D017077:Culture Media, Conditioned; D016207:Cytokines; D036341:Intercellular Signaling Peptides and Proteins; C070896:M-cadherin