Institute for Tissue Engineering and Regenerative Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China.
School of Biomedical Sciences, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China.
Stem Cell Res Ther. 2022 Aug 13;13(1):419. doi: 10.1186/s13287-022-03095-5.
Critical limb ischemia (CLI) is the most severe form of peripheral artery disease and exhibits a high risk of lower extremity amputations. As even the most promising experimental approaches based on mesenchymal stem cells (MSCs) demonstrated only moderate therapeutic effects, we hypothesized that other cell types with intrinsic roles in angiogenesis may exhibit a stronger therapeutic potential. We have previously established a protocol to source human peripheral blood-derived angiogenic cells (BDACs). These cells promoted revascularization and took perivascular location at sites of angiogenesis, thus resembling hematopoietic pericytes, which were only described in vivo so far. We thus hypothesized that BDACs might have a superior ability to promote revascularization and rescue the affected limb in CLI.
As standard BDAC sourcing techniques involve the use of animal-derived serum, we sought to establish a xeno- and/or serum-free protocol. Next, BDACs or MSCs were injected intramuscularly following the ligation of the iliac artery in a murine model. Their ability to enhance revascularization, impair necrosis and modulate inflammatory processes in the affected limb was investigated. Lastly, the secretomes of both cell types were compared to find potential indications for the observed differences in angiogenic potential.
From the various commercial media tested, one xeno-free medium enabled the derivation of cells that resembled functional BDACs in comparable numbers. When applied to a murine model of CLI, both cell types enhanced limb reperfusion and reduced necrosis, with BDACs being twice as effective as MSCs. This was also reflected in histological evaluation, where BDAC-treated animals exhibited the least muscle tissue degeneration. The BDAC secretome was enriched in a larger number of proteins with pro-angiogenic and anti-inflammatory properties, suggesting that the combination of those factors may be responsible for the superior therapeutic effect.
Functional BDACs can be sourced under xeno-free conditions paving the way for their safe clinical application. Since BDACs are derived from an easily accessible and renewable tissue, can be sourced in clinically relevant numbers and time frame and exceeded traditional MSCs in their therapeutic potential, they may represent an advantageous cell type for the treatment of CLI and other ischemic diseases.
严重肢体缺血（CLI）是外周动脉疾病最严重的形式，下肢截肢风险很高。即使是基于间充质干细胞（MSCs）的最有前途的实验方法也仅显示出中等的治疗效果，因此我们假设其他在血管生成中具有内在作用的细胞类型可能具有更强的治疗潜力。我们之前已经建立了一种从人外周血中获取血管生成细胞（BDACs）的方案。这些细胞促进了再血管化，并在血管生成部位占据了血管周细胞的位置，因此类似于目前仅在体内描述的造血周细胞。因此，我们假设 BDACs 可能具有更强的促进再血管化和拯救 CLI 受累肢体的能力。
由于标准的 BDAC 采集技术涉及使用动物源性血清，我们试图建立一个无动物源和/或无血清的方案。接下来，在小鼠模型中结扎髂动脉后，将 BDAC 或 MSC 肌肉内注射。研究它们增强再血管化、减少坏死和调节受累肢体炎症过程的能力。最后，比较两种细胞类型的分泌组，以寻找观察到的血管生成潜力差异的潜在迹象。
在所测试的各种商业培养基中，一种无动物源培养基能够衍生出数量相当的类似功能 BDAC。当应用于 CLI 小鼠模型时，两种细胞类型都增强了肢体再灌注并减少了坏死，BDAC 的效果是 MSC 的两倍。这也反映在组织学评估中，BDAC 治疗的动物表现出的肌肉组织退化最少。BDAC 分泌组富含大量具有促血管生成和抗炎特性的蛋白质，这表明这些因素的组合可能是其优越治疗效果的原因。
BDAC 可以在无动物源条件下获得，为其安全的临床应用铺平了道路。由于 BDAC 来源于易于获得和可再生的组织，可以在临床相关数量和时间范围内获得，并且在治疗潜力上超过传统的 MSC，因此它们可能是治疗 CLI 和其他缺血性疾病的有利细胞类型。
