Petru Poni Institute of Macromolecular Chemistry, Iasi, Romania.
Stem Cells Dev. 2013 Feb 15;22(4):643-53. doi: 10.1089/scd.2012.0273. Epub 2012 Oct 19.
Stem cell-based therapy for myocardial regeneration has reported several functional improvements that are attributed mostly to the paracrine effects stimulating angiogenesis and cell survival. This study was conducted to comparatively evaluate the potential of factors secreted by mesenchymal stem cells (MSCs) in normoxic and hypoxic conditions to promote tissue repair by sustaining endothelial cell (EC) adhesion and proliferation and conferring protection against apoptosis. To this aim, a conditioned medium (CM) was generated from MSCs after 24-h incubation in a serum-free normal or hypoxic environment. MSCs exhibited resistance to hypoxia, which induced increased secretion of vascular endothelial growth factor (VEGF) and decreased levels of other cytokines, including stromal-derived factor-1 (SDF). The CM derived from normal (nMSC-CM) and hypoxic cells (hypMSC-CM) induced similar protective effects on H9c2 cells in hypoxia. Minor differences were noticed in the potential of normal versus hypoxic CM to promote angiogenesis, which were likely connected to SDFα and VEGF levels: the nMSC-CM was more effective in stimulating EC migration, whereas the hypMSC-CM had an enhanced effect on EC adhesion. However, the factors secreted by MSCs in normoxic or hypoxic conditions supported adhesion, but not proliferation, of ECs in vitro, as revealed by impedance-based dynamic assessments. Surprisingly, factors secreted by other stem/progenitor cells, such as endothelial progenitor cells (EPCs), had complementary effects to the MSC-CM. Thus, the EPC-CM, in either a normal or hypoxic environment, supported EC proliferation, but did not sustain EC adhesion. Combined use of the MSC-CM and EPC-CM promoted both EC adhesion and proliferation, suggesting that the local angiogenesis at the site of ischemic injury might be better stimulated by simultaneous releasing of factors secreted by multiple stem/progenitor cell populations.
基于干细胞的心肌再生治疗已经报道了几种功能改善，这些改善主要归因于旁分泌作用，刺激血管生成和细胞存活。本研究旨在比较评价骨髓间充质干细胞（MSCs）在常氧和低氧条件下分泌的因子促进组织修复的潜力，这些因子可以维持内皮细胞（EC）的黏附和增殖，并赋予其抗凋亡作用。为此，将 MSCs 在无血清的正常或低氧环境中孵育 24 小时后生成条件培养基（CM）。MSCs 对低氧具有抗性，这会诱导血管内皮生长因子（VEGF）的分泌增加，同时其他细胞因子（包括基质衍生因子-1（SDF））的水平降低。正常（nMSC-CM）和低氧细胞（hypMSC-CM）来源的 CM 在低氧条件下对 H9c2 细胞均具有相似的保护作用。在促进血管生成方面，正常和低氧 CM 的潜力存在微小差异，这可能与 SDFα和 VEGF 水平有关：nMSC-CM 更有效地刺激 EC 迁移，而 hypMSC-CM 对 EC 黏附的增强作用更强。然而，MSCs 在常氧或低氧条件下分泌的因子在体外支持 EC 的黏附，但不支持增殖，这是通过基于阻抗的动态评估揭示的。令人惊讶的是，其他干细胞/祖细胞（如内皮祖细胞（EPCs））分泌的因子对 MSC-CM 具有补充作用。因此，EPC-CM 无论是在正常还是低氧环境中，均支持 EC 的增殖，但不能维持 EC 的黏附。MSC-CM 和 EPC-CM 的联合使用促进了 EC 的黏附和增殖，这表明在缺血损伤部位，通过同时释放多种干细胞/祖细胞群体分泌的因子，可以更好地刺激局部血管生成。
