Tasev Dimitar, Dekker-Vroling Laura, van Wijhe Michiel, Broxterman Henk J, Koolwijk Pieter, van Hinsbergh Victor W M
Department of Physiology, Amsterdam Cardiovascular Sciences, Amsterdam University Medical Centers, Amsterdam, Netherlands.
Department of Medical Oncology, Amsterdam University Medical Centers, Amsterdam, Netherlands.
Front Med (Lausanne). 2018 Dec 20;5:356. doi: 10.3389/fmed.2018.00356. eCollection 2018.
Vascular homeostasis and regeneration in ischemic tissue relies on intrinsic competence of the tissue to rapidly recruit endothelial cells for vascularization. The mononuclear cell (MNC) fraction of blood contains circulating progenitors committed to endothelial lineage. These progenitors give rise to endothelial colony-forming cells (ECFCs) that actively participate in neovascularization of ischemic tissue. To evaluate if the initial clonal outgrowth of ECFCs from cord (CB) and peripheral blood (PB) was stimulated by hypoxic conditions, MNCs obtained from CB and PB were subjected to 20 and 1% O cell culture conditions. Clonal outgrowth was followed during a 30 day incubation period. Hypoxia impaired the initial outgrowth of ECFC colonies from CB and also reduced their number that were developing from PB MNCs. Three days of oxygenation (20% O) prior to hypoxia could overcome the initial CB-ECFC outgrowth. Once proliferating and subcultured the CB-ECFCs growth was only modestly affected by hypoxia; proliferation of PB-ECFCs was reduced to a similar extent (18-30% reduction). Early passages of subcultured CB- and PB-ECFCs contained only viable cells and few if any senescent cells. Tube formation by subcultured PB-ECFCs was also markedly inhibited by continuous exposure to 1% O. Gene expression profiles point to regulation of the cell cycle and metabolism as major altered gene clusters. Finally we discuss our counterintuitive observations in the context of the important role that hypoxia has in promoting neovascularization.
缺血组织中的血管稳态和再生依赖于组织迅速募集内皮细胞进行血管化的内在能力。血液中的单核细胞（MNC）部分含有定向于内皮谱系的循环祖细胞。这些祖细胞产生内皮集落形成细胞（ECFC），其积极参与缺血组织的新生血管形成。为了评估来自脐带血（CB）和外周血（PB）的ECFC的初始克隆生长是否受到缺氧条件的刺激，将从CB和PB获得的MNC置于20%和1%氧气的细胞培养条件下。在30天的孵育期内跟踪克隆生长情况。缺氧损害了CB中ECFC集落的初始生长，也减少了从PB MNC发育而来的集落数量。在缺氧之前进行三天的充氧（20%氧气）可以克服CB-ECFC的初始生长。一旦增殖并传代培养，CB-ECFC的生长仅受到缺氧的适度影响；PB-ECFC的增殖也减少到类似程度（减少18-30%）。传代培养的CB-和PB-ECFC的早期传代仅包含活细胞，几乎没有衰老细胞。持续暴露于1%氧气也显著抑制了传代培养的PB-ECFC的管形成。基因表达谱表明细胞周期和代谢的调节是主要改变的基因簇。最后，我们在缺氧在促进新生血管形成中的重要作用的背景下讨论了我们的反直觉观察结果。
