维生素D调控的血管新生在糖尿病足溃疡愈合中的作用研究

Along with the development of nutriology, new functions of some nutrients have been reported, which included the relationship between vitamin D and wound healing in the diabetic foot ulcer. The diabetic foot ulcer is a significant cause of amputation as well as death among diabetic patients. However, the mechanism underlying delayed wound healing in diabetic foot ulcer was not fully understood, and the current therapy is not as well as people expected. In 1903, the Nobel prize was granted to Dr. Finsen because of his work on treating lupus by sunlight. But the effect and mechanism of vitamin D on wound healing in the diabetic foot ulcer was unclear. Angiogenesis play an important role in wound healing and impaired angiogenesis is a leading factor contributing to delayed wound healing in diabetic foot ulcer. Therefore, this study was designed to explore the effect of vitamin D on wound healing in diabetic foot ulcer and the mechanism by vitamin D-induced angiogenesis. We propose to comprehensively 1) examine the effect of vitamin D supplementation on wound healing and ulcer symptoms, such as erythema, discharge and necrosis, in patients with diabetic foot ulcer; 2) explore the potential of vitamin D intervention on wound healing, angiogenesis and proangiogenic molecules using diabetic wound animal model; 3) evaluate that whether calcitriol induce angiogenic molecules in HUVECs, its effect on cell apoptosis, cell migration and angiogenesis in vitro and the underlying molecular mechanism. Findings from this study will provide theoretical evidence for developing strategies relating to prevention and therapy of diabetic foot ulcer.

随着营养学的发展，一些营养素的新功能逐渐被发现，维生素D（VD）与糖尿病足溃疡（DFU）的关系亦得到关注。早在上个世纪，丹麦医生芬森曾发现晒太阳治疗皮肤狼疮并因此荣获诺奖，但VD对DFU创面愈合的影响及机制尚不明确。血管新生在创面愈合中发挥重要作用，血管新生障碍是导致DFU患者创面难愈的重要原因之一。结合前期研究结果，本研究提出VD可能通过调控血管新生促进DFU创面愈合的假说。为验证此假说，首先在DFU患者中开展人群干预研究，观察VD补充对创面愈合、肉芽生成和皮肤组织内血管新生标记物等的影响。同时构建DFU动物模型，进行VD干预试验，分析VD干预对DFU创面愈合、血管新生及相关因子的影响，及其剂量效应关系。另外结合细胞实验，探究VD处理对高糖刺激下细胞增殖、凋亡、迁移和血管生成能力的影响及分子机制，多层次阐述VD调控的血管新生在DFU创面愈合中的作用，为VD防治DFU提供基础资料。

糖尿病是全球面临的重大公共卫生问题，根据国际糖尿病联盟公布的数据显示，2021年全球约5.37亿成年人患有糖尿病，近年来该疾病的患病率及病死率逐步升高。糖尿病足溃疡是糖尿病患者中致残致死的重要并发症，具有难治性、截肢率高以及复发性高等特征，严重影响患者的生命质量。糖尿病足溃疡创面迁延不愈的原因较为复杂，包括血管新生受损、炎症期过度延长、以及细胞外基质沉积和肉芽组织形成受阻等。而难以愈合的创面也进一步增加了创面感染的风险。维生素D与糖尿病足溃疡的关系逐渐得到关注，但其涉及的具体机制尚不明确。本项目首先构建了糖尿病溃疡模型小鼠，进行活性维生素D干预实验，结果显示，不同剂量的活性维生素D干预有助于促进糖尿病溃疡模型小鼠的皮肤创面愈合，缓解过度延长的炎症状态，促进皮肤创缘组织内的血管新生，提高血管新生相关因子的表达水平，且有助于改善糖尿病溃疡模型小鼠皮肤创面愈合过程中的血管内皮功能障碍。随后本项目开展体外细胞实验，评估活性维生素D对高糖背景下人脐静脉血管内皮细胞（HUVECs）的增殖、迁移、管腔形成能力以及血管新生等能力的影响，研究结果显示，活性维生素D干预有助于促进高糖背景下HUVECs细胞的增殖和迁移能力，并减少细胞凋亡，受损的Matrigel小管形成能力亦得到改善，而且活性维生素D有助于提升HIF-1α及VEGF等促血管生成因子的表达。最后，本项目进一步开展整体动物实验，评价不同维生素D状态对健康小鼠皮肤创面愈合的影响，研究结果显示，缺乏维生素D使得健康小鼠皮肤创面愈合速度明显延缓，创面愈合过程中炎症期持续时间过长，上皮细胞-间充质转换过程亦减缓，此外，细胞外基质沉积进程减缓，皮肤创面愈合质量降低。以上研究结果将为我们深入了解维生素D防治糖尿病足溃疡的作用机理提供重要的科学依据。