Blood-derived progenitor cell transplantation holds potential for the treatment of severe vascular diseases. Human umbilical cord blood (UCB)-derived hematopoietic progenitor cells purified using high aldehyde dehydrogenase (ALDH) activity demonstrate pro-angiogenic functions following intramuscular transplantation into immunodeficient mice with hind-limb ischemia. Unfortunately, UCB ALDHhi cells are rare and prolonged ex vivo expansion leads to loss of high ALDH-activity and diminished vascular regenerative function. ALDH-activity generates retinoic acid, a potent driver of hematopoietic differentiation, creating a paradoxical challenge to expand UCB ALDHhi cells while limiting differentiation and retaining pro-angiogenic functions.
In Jan 27 , 2018, TT Cooper and others published an article in << Stem Cells >> which title is “Inhibition Of Aldehyde Dehydrogenase-Activity Expands Multipotent Myeloid Progenitor Cells With Vascular Regenerative Function”.,br>
They investigated whether inhibition of ALDH-activity during ex vivo expansion of UCB ALDHhi cells would prevent differentiation and expand progeny that retained pro-angiogenic functions after transplantation into NOD/SCID mice with femoral artery ligation-induced unilateral hind-limb ischemia. Human UCB ALDHhi cells were cultured under serum-free conditions for 9 days, with or without the reversible ALDH-inhibitor, diethylaminobenzaldehyde (DEAB). Although total cell numbers were increased >70-fold, the frequency of cells that retained ALDHhi /CD34+ phenotype was significantly diminished under basal conditions. In contrast, DEAB-inhibition increased total ALDHhi /CD34+ cell number by ≥ 10-fold, reduced differentiation marker (CD38) expression, and enhanced the retention of multipotent colony-forming cells in vitro.
Proteomic analysis revealed that DEAB-treated cells upregulated anti-apoptotic protein expression and diminished production of proteins implicated with megakaryocyte differentiation. Intramuscular transplantation of DEAB-treated cells into mice with hind-limb ischemia stimulated endothelial cell proliferation and augmented recovery of hind-limb perfusion. DEAB-inhibition of ALDH-activity delayed hematopoietic differentiation and expanded multipotent myeloid cells that accelerated vascular regeneration following intramuscular transplantation in vivo.
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