Critical limb ischemia (CLI) is a severe state of peripheral artery disease with high unmet clinical needs. Further, there are no effective treatment options for CLI patients. Based on preclinical study results, predicting the clinical efficacy of CLI treatments is typically difficult because conventional hindlimb ischemia (HLI) rodent models display spontaneous recovery from ischemia, which is not observed in CLI patients. Therefore, we aimed to develop a novel chronic and severe HLI model to properly evaluate the therapeutic effects of drug candidates for CLI. Severe HLI mice (Type-N) were generated by increasing the excised area of blood vessels in a hindlimb of NOG mice. We selected chronic Type-N mice without spontaneous recovery of blood flow based on the number of necrotic nails and blood flow rate at 2 weeks after surgery. Immunohistochemistry and gene expression analysis at 9 weeks after the Type-N operation revealed that the ischemic limb was in a steady state with impaired angiogenesis, like that observed in CLI patients. Therapeutic treatment with cilostazol, which is used for intermittent claudication, did not restore blood flow in chronic Type-N mice. In contrast, therapeutic transplantation of pericytes and vascular endothelial cells, which can form new blood vessels in vivo, significantly improved blood flow in a subset of Type-N mice. These findings suggest that this novel chronic and severe HLI model may be a valuable standard animal model for therapeutic evaluation of the angiogenic effects of CLI drug candidates.

中文翻译：

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一种新型的慢性肢体缺血模型，可通过治疗性方法评估候选药物的血管生成作用

严重肢体缺血（CLI）是一种严重的外周动脉疾病，临床需求尚未得到满足。此外，对于CLI患者没有有效的治疗选择。根据临床前研究结果，通常很难预测CLI的临床疗效，因为常规的后肢缺血（HLI）啮齿动物模型显示出自缺血的自发恢复，而在CLI患者中未观察到这种恢复。因此，我们旨在开发一种新型的慢性和严重HLI模型，以正确评估CLI候选药物的治疗效果。通过增加NOG小鼠后肢中血管的切除面积来生成严重的HLI小鼠（N型）。我们根据坏死指甲的数量和术后2周的血流速度选择了没有自发恢复血流的慢性N型小鼠。N型手术后9周的免疫组织化学和基因表达分析表明，缺血性肢体处于稳定状态，血管生成受损，如在CLI患者中观察到的那样。西洛他唑用于间歇性lau行的治疗性治疗无法恢复慢性N型小鼠的血流。相反，可以在体内形成新血管的周细胞和血管内皮细胞的治疗性移植显着改善了N型小鼠亚群中的血流。这些发现表明，这种新颖的慢性和严重HLI模型可能是用于CLI候选药物血管生成作用治疗评估的有价值的标准动物模型。