DOI:10.20047/j.issn1673-7210.25092184
中图分类号:R587.2
翁于格, 徐腾姣, 黄诒洁, 丁艳
| 【作者机构】 | 海南医科大学附属皮肤病医院皮肤科 |
| 【分 类 号】 | R587.2 |
| 【基 金】 | 海南省卫生健康科技创新联合项目(WSJK2024 MS237)。 |
根据国际糖尿病联盟预测,2021年全球糖尿病患病率为10.5%,到2045年将增至12.2%[1]。糖尿病足溃疡(diabetic foot ulcer,DFU)是由神经病变、缺血或两者均有所致的糖尿病并发症之一,其终身发病风险为19%~34%,是非创伤性截肢的主要原因[2]。该病还伴随高死亡率及高昂医疗开支,对患者生活和社会医疗体系造成沉重负担。因此,亟须发展新型治疗手段以促进DFU创面修复。近年来,间充质干细胞外泌体(mesenchymal stem cell exosome,MSC-Exos)复合水凝胶因其免疫、血管调节特性和良好药物控释及递送能力,具有远大应用前景[3]。研究显示,间充质干细胞在低氧环境下可激活HIF-1α信号通路[4]。早期上调HIF-1α信号通路可促进血管生成,并激活下游如血管内皮生长因子(vascular endothelial growth factor,VEGF)、基质细胞衍生因子(stromal cell-derived factor,SDF)-1α及血小板衍生生长因子(platele derived growth factor,PDGF)-β等关键因子加速血管网络重建[5-6]。基于信号通路的研究更能精准阐明其治疗机制,为皮肤创伤及DFU等急慢性伤口创面愈合提供建设性想法和启示。
DFU的发生和进展涉及多种病理机制的级联反应,其核心诱因包括周围神经病变和缺血性病变,而感染通常是继发因素[7]。长期高血糖可激活多元醇途径、引发氧化应激,并促进晚期糖基化终产物积聚,导致神经轴突变性和脱髓鞘,临床表现为感觉异常与皮肤干燥,显著增高足部溃疡风险[8]。糖尿病状态下,相关炎症因子与生长因子长期失衡加剧足部溃疡伤口迁延不愈,同时招募中性粒细胞和单核细胞等免疫细胞浸润,影响内皮祖细胞和血管相关细胞功能[9-11]。此外,高血糖经多途径干扰不同愈合阶段:炎症期巨噬细胞功能紊乱延缓炎症消退;增殖期血管新生与上皮再生受阻;重塑期成纤维细胞功能异常及细胞外基质代谢失调,造成胶原沉积异常或停滞[7-8]。
间充质干细胞是一种具有多向分化潜能及免疫与血管调节功能的成体干细胞[12]。近年来,间充质干细胞的治疗效果主要与外泌体有关,可作用于DFU创面愈合的不同时期[12]。外泌体为直径40~200 nm的一类具有显著治疗潜力的脂质双层囊泡,可携带蛋白质、mRNA等生物活性物质,通过旁分泌机制调节免疫反应、减轻炎症、促进血管生成和巨噬细胞极化等方式推动DFU愈合[13]。然而,外泌体直接应用易受创面液体冲刷和机械摩擦影响,限制其修复效能。水凝胶作为外泌体理想载体,因其优良保水性、生物相容性及类似细胞外基质的结构特性,能为外泌体提供滞留载体与缓释环境,维持创面湿润与低氧状态,促进细胞迁移与黏附,从而协同增强修复效果[14]。研究显示,负载人脐带或牙龈间充质干细胞来源的外泌体水凝胶能显著促进创面愈合,其在糖尿病大鼠模型中使伤口闭合率提高至92.7%,甚至更高,这便是有力证据[15-16]。因此,将MSC-Exos与水凝胶结合应用可协同促进DFU愈合,基于其安全性和稳定性,开发外泌体新型递送系统已成为目前研究热点。
与急性伤口中的短暂性缺氧不同,DFU呈现持续病理性低氧状态,其源于血管系统受损导致的氧供应不足与修复细胞高氧需求间的失衡,这种长期低氧微环境可抑制成纤维细胞增殖、胶原沉积和血管生成,加剧氧化应激和炎症反应,形成恶性循环[3,7]。HIF-1是DFU创面低氧响应的核心调控因子,由氧敏感性α亚基如HIF-1α和结构性表达β亚基如HIF-1β/ARNT构成异源二聚体,在不同免疫细胞如巨噬细胞、中性粒细胞、T淋巴细胞等,以及非免疫细胞如滑膜成纤维细胞和胰岛β细胞等中均有表达,其活性受氧依赖性羟化酶动态调节,缺氧环境下,羟化酶失活导致HIF-1α稳定入核,激活下游百余种靶基因[17]。长期高血糖可通过直接抑制HIF-1α表达、加速HIF-1α蛋白酶体降解及对HIF-1α稳定性和功能负调节作用等影响HIF-1α信号通路的功能,表现出血管生成减少、内皮祖细胞归巢能力下降和伤口愈合延迟的特点[18]。相反,应用脯氨酸羟化酶抑制剂、缺氧脂肪干细胞外泌体等途径稳定HIF-1α表达,可调节微血管环境加速DFU愈合[19]。因此,早期上调HIF-1α以加速血管网络形成非常重要。
缺氧反应受损和微血管损伤是DFU伤口延迟愈合的主要原因,组织缺氧又是血管生成的关键驱动力[20]。研究显示,MSC-Exos在缺氧条件下激活HIF-1α信号通路[21]。水凝胶作为理想载体维持低氧环境,有利于HIF-1α信号通路被特异性激活并通过协调血管新生与炎症反应动态平衡促进愈合进程[22]。
研究显示,VEGF、PDGF-β、SDF-1α 3种细胞因子均由HIF-1所调控,这些因子对DFU微血管的修复至关重要[23-25]。VEGF启动血管新生,是HIF-1α的直接靶基因,其表达受HIF-1α调控。VEGF不仅直接刺激内皮细胞增殖、迁移和管腔形成,还通过促进巨噬细胞M2极化间接促进皮肤创伤愈合,这种双重作用机制使VEGF成为生理性血管生成和病理性修复如肿瘤生长、伤口愈合的核心调控因子[26]。VEGF因蛋白半衰期短而限制其持续效应,采用MSC-Exos水凝胶缓释体系,经由物理包埋或化学交联方式将外泌体锚定于损伤区域,实现数天至数周的缓慢释放,进而维持HIF-1α/VEGF信号通路的长效活化[27]。SDF-1α是干细胞归巢的核心调控因子,在HIF-1α的调控下表达,通过激活CXCR4受体,触发下游信号通路如PI3K/Akt、JAK/STAT,与VEGF协同介导内皮祖细胞从骨髓向创面定向迁移和招募[28-30]。一项纳入150例DFU患者的研究显示,血清SDF-1α浓度与Wagner分级呈负相关,其水平随病变严重程度加重而递减,预后不佳患者该指标下降幅度达40%[31]。Zhang等[32]研究显示,GDF11通过抗氧化机制增强HIF-1α活性,上调SDF-1和VEGF的表达,介导内皮祖细胞动员和新生血管形成。此外,在骨再生和脑缺血模型中,HIF-1α/SDF-1α/CXCR4轴被证实是血管生成的关键驱动力[33]。PDGF-β在DFU修复中的作用可能与促进血管平滑肌细胞的增殖和迁移有关,通过激活下游PI3K/Akt、MAPK信号通路,间接增强HIF-1α转录活性,促进胶原合成与细胞外基质沉积,有助于血管稳定、修复和成熟[34-35]。同时,通过SDF-1α招募的骨髓来源细胞如内皮祖细胞或免疫细胞可分泌PDGF等因子[34]。临床研究显示,胫骨横向牵引如胫骨横向骨搬运技术通过施加机械应力触发局部缺氧微环境,激活HIF-1α表达,进而介导VEGF、PDGF-BB和SDF-1α协同上调,进一步放大修复信号显著改善DFU缺血状态[36]。由此可见,单一因子疗法在糖尿病模型中易受高糖环境影响而降低疗效[36]。相比之下,外源性补充血管生成相关因子如VEGF、PDGF-BB、SDF-1等多因子联合或HIF-1α介导整体调控如胫骨横向骨搬运技术能更全面地促进愈合[36-37]。综上所述,VEGF、PDGF-β、SDF-1α并非单独发挥作用,而是HIF-1α通过时空特异性表达协调三者功能,在缺血修复中发挥核心作用。
微血管损伤是DFU的重要特征,国内外多项研究成果均表明富含MSC-Exos水凝胶为DFU治疗提供“无细胞”创新策略。研究显示,VEGF、PDGF-β、SDF-1α均由HIF-1α调控且PDGF-β与HIF-1α/VEGF/SDF-1α信号通路形成协同效应,并通过促血管生成与成熟、基质重塑和干细胞归巢协同加速DFU修复,其潜在机制可能与HIF-1α诱导的血管生成有关,而MSC-Exo与水凝胶分别从生物学功能与物理支架层面共同推动创面修复进程[36,38]。
目前研究多基于HIF-1α信号通路及单个因子调控,对多因子介导的信号通路尚未深入研究。MSC-Exos水凝胶在低氧环境下可稳定HIF-1α并激活其靶基因如VEGF、SDF-1α和PDGF-β等,可能是修复DFU微血管损伤的重要机制,但存在以下关键研究不足:①MSC-Exos能否完全直接调控HIF-1α信号通路尚未完全明确;②外泌体内容物如何特异性影响HIF-1α的稳定性或转录活性促进DFU愈合需要更深入研究,为将来提供更多直接证据;③低氧刺激下,外泌体内容物能否通过HIF-1α下游效应分子发挥作用需进一步验证;④VEGF/SDF-1α/PDGF-β的协同机制尚不明确,HIF-1α与下游效应分子VEGF/SDF-1α/PDGF-β信号传导间的相互作用还需进一步阐明。未来研究应从以下3个方面突破目前治疗DFU瓶颈:①深化机制研究,解析HIF-1α信号通路的核心作用,聚焦于精准调控HIF-1α活性,平衡促血管生成、抗炎/抗纤维化与促肿瘤风险并建立多因子协同模型;②加快开发智能响应型递送系统、基因编辑技术如CRISPR-Cas9与纳米医学技术,推动外泌体临床转化与标准化生产;③设计多中心随机对照试验,比较不同来源外泌体如脐带、骨髓和脂肪的效果差异。未来还需推动该疗法从机制研究向精准给药、动态监测及个体化治疗迈进,推动DFU治疗进入“精准医学”时代。
利益冲突声明:本文所有作者均声明不存在利益冲突。
[1] SUN H,SAEEDI P,KARURANGA S,et al. IDF diabetes atlas:global,regional and country-level diabetes prevalence estimates for 2021 and projections for 2045 [J]. Diabetes Res Clin Pract,2022,183:109119.
[2] MCDERMOTT K,FANG M,BOULTON A J M,et al. Etiology,epidemiology,and disparities in the burden of diabetic foot ulcers [J]. Diabetes Care,2023,46(1):209-221.
[3] WU S,ZHOU Z,LI Y,et al. Advancements in diabetic foot ulcer research:focus on mesenchymal stem cells and their exosomes [J]. Heliyon,2024,10(17):e37031.
[4] 侯婧瑛,于萌蕾,郭天柱,等. 缺氧预处理激活HIF-1α/MALAT1/VEGFA通路促进骨髓间充质干细胞生存和血管再生[J]. 中国组织工程研究,2021,25(7):985-990.
[5] CHOWDHURY M F I,MOKHTARI-ESBUIE F,YAZDANI A,et al. Upregulation of downstream angiogenic genes using mRNA for the transfection of transcription factor hypoxia inducible factor 1 alpha:a short communication [J]. Arch Gastroenterol Res,2025,6(1):40-44.
[6] GHOSH R,SAMANTA P,SARKAR R,et al. Targeting HIF-1α by natural and synthetic compounds:a promising approach for anti-cancer therapeutics development [J].Molecules,2022,27(16):5192.
[7] HUANG F,LU X,YANG Y,et al. Microenvironmentbased diabetic foot ulcer nanomedicine [J]. Adv Sci(Weinh),2023,10(2):e2203308.
[8] CHONG Z Z,MENKES D L,SOUAYAH N,et al. Targeting neuroinflammation in distal symmetrical polyneuropathy in diabetes [J]. Drug Discov Today,2024,29(8):104087.
[9] YANG D R,WANG M Y,ZHANG C L,et al. Endothelial dysfunction in vascular complications of diabetes:a comprehensive review of mechanisms and implications [J].Front Endocrinol(Lausanne),2024,15:1359255.
[10] LIU Y,LYONS C J,AYU C,et al. Enhancing endothelial colony-forming cells for treating diabetic vascular complications:challenges and clinical prospects [J]. Front Endocrinol(Lausanne),2024,15:1396794.
[11] LIU Y,LIU Y,DENG J,et al. Fibroblast growth factor in diabetic foot ulcer:progress and therapeutic prospects [J].Front Endocrinol(Lausanne),2021,12:744868.
[12] WU J,CHEN L H,SUN S Y,et al. Mesenchymal stem cell-derived exosomes:the dawn of diabetic wound healing [J]. World J Diabetes,2022,13(12):1066-1095.
[13] 刘妮妮,余明珠,李肖娟,等. 间充质干细胞来源的外泌体治疗糖尿病足溃疡的研究进展[J]. 临床医学进展,2024,14(3):8-14.
[14] ZHAO L,ZHOU Y,ZHANG J,et al. Natural polymer-based hydrogels:from polymer to biomedical applications [J].Pharmaceutics,2023,15(10):2514.
[15] QIU X,WANG M,TANG J,et al. Chitosan hydrogel loaded with human umbilical cord mesenchymal stem cell-derived exosomes promotes healing of chronic diabetic wounds in rats [J]. Nan Fang Yi Ke Da Xue Xue Bao,2025,45(10):2082-2091.
[16] SHI Q,QIAN Z,LIU D,et al. GMSC-derived exosomes combined with a chitosan/silk hydrogel sponge accelerates wound healing in a diabetic rat skin defect model [J].Front Physiol,2017,8:904.
[17] TANG Y Y,WANG D C,WANG Y Q,et al. Emerging role of hypoxia-inducible factor-1α in inflammatory autoimmune diseases:a comprehensive review [J]. Front Immunol,2023,13:1073971.
[18] BOTUSAN I R,SUNKARI V G,SAVU O,et al. Stabilization of HIF-1α is critical to improve wound healing in diabetic mice [J]. Proc Natl Acad Sci U S A,2008,105(49):19426-19431.
[19] ZHU D,WEI W,ZHANG J,et al. Mechanism of damage of HIF-1 signaling in chronic diabetic foot ulcers and its related therapeutic perspectives [J]. Heliyon,2024,10(3):e24656.
[20] HAN C,SINGLA R K,WANG C,et al. Application of biomaterials in diabetic wound healing:the recent advances and pathological aspects [J]. Pharmaceutics,2025,17(10):1295.
[21] GAO W,HE R,REN J,et al. Exosomal HMGB1 derived from hypoxia-conditioned bone marrow mesenchymal stem cells increases angiogenesis via the JNK/HIF-1αpathway [J]. FEBS Open Bio,2021,11(5):1364-1373.
[22] CHEN H,JIA P,KANG H,et al. Upregulating HIF-1αby hydrogel nanofibrous scaffolds for rapidly recruiting angiogenesis relative cells in diabetic wound [J]. Adv Healthc Mater,2016,5(7):907-918.
[23] FORSYTHE J A,JIANG B H,IYER N V,et al. Activation of vascular endothelial growth factor gene transcription by hypoxia-inducible factor 1 [J]. Mol Cell Biol,1996,16(9):4604-4613.
[24] SCHITO L,REY S,TAFANI M,et al. Hypoxia-inducible factor 1-dependent expression of platelet-derived growth factor B promotes lymphatic metastasis of hypoxic breast cancer cells [J]. Proc Natl Acad Sci U S A,2012,109(40):E2707-E2716.
[25] AMIN K N,UMAPATHY D,ANANDHARAJ A,et al.miR-23c regulates wound healing by targeting stromal cell-derived factor-1α(SDF-1α/CXCL12) among patients with diabetic foot ulcer [J]. Microvasc Res,2020,127:103924.
[26] MAGAR A G,MORYA V K,KWAK M K,et al. A molecular perspective on HIF-1α and angiogenic stimulator networks and their role in solid tumors:an update [J]. Int J Mol Sci,2024,25(6):3313.
[27] YANG F,LI Z,CAI Z,et al. Pluronic F-127 hydrogel loaded with human adipose-derived stem cell-derived exosomes improve fat graft survival via HIF-1α-mediated enhancement of angiogenesis [J]. Int J Nanomedicine,2023,18:6781-6796.
[28] YANG H,HE C,BI Y,et al. Synergistic effect of VEGF and SDF-1α in endothelial progenitor cells and vascular smooth muscle cells [J]. Front Pharmacol,2022,13:914347.
[29] WANG X,JIANG H,GUO L,et al. SDF-1 secreted by mesenchymal stem cells promotes the migration of endothelial progenitor cells via CXCR4/PI3K/Akt pathway [J].J Mol Histol,2021,52(6):1155-1164.
[30] XIONG W,GUO X,CAI X. SDF-1/CXCR4 axis promotes osteogenic differentiation of BMSCs through the JAK2/STAT3 pathway [J]. Folia Histochem Cytobiol,2021,59(3):187-194.
[31] 王梦竹,王淑文,董晓芬,等. 血清SDF-1α、CXCR4与糖尿病足溃疡感染、病情程度及预后的相关性[J]. 临床和实验医学杂志,2023,22(17):1846-1850.
[32] ZHANG Y,ZHANG Y Y,PAN Z W,et al. GDF11 promotes wound healing in diabetic mice via stimulating HIF-1α-VEGF/SDF-1α-mediated endothelial progenitor cell mobilization and neovascularization [J]. Acta Pharmacol Sin,2023,44(5):999-1013.
[33] XUE Y,LI Z,WANG Y,et al. Role of the HIF1α/SDF1/CXCR4 signaling axis in accelerated fracture healing after craniocerebral injury [J]. Mol Med Rep,2020,22(4):2767-2774.
[34] POPIELARCZYK T L,HUCKLE W R,BARRETT J G,et al. Human bone marrow-derived mesenchymal stem cells home via the PI3K-Akt,MAPK,and JAK/STAT signaling pathways in response to platelet-derived growth factor [J]. Stem Cells Dev,2019,28(17):1191-1202.
[35] CHEN J,CUI X,QIAN Z,et al. Multi omics analysis reveals regulators of the response to PDGF BB treatment in pulmonary artery smooth muscle cells [J]. BMC Genomics,2016,17(1):781.
[36] LIU J,HUANG X,SU H,et al. Tibial cortex transverse transport facilitates severe diabetic foot wound healing via HIF-1α induced angiogenesis [J]. J Inflamm Res,2024,17:2681-2696.
[37] WHITE M J V,BRIQUEZ P S,WHITE D A V,et al.VEGF-A,PDGF-BB and HB-EGF engineered for promiscuous super affinity to the extracellular matrix improve wound healing in a model of type 1 diabetes [J].NPJ Regen Med,2021,6(1):76.
[38] MALLANAGOUDRA P,M RAMAKRISHNA S S,JAISWAL S,et al. Progressive hydrogel applications in diabetic foot ulcer management:phase-dependent healing strategies [J]. Polymers(Basel),2025,17(17):2303.
Research progress on mesenchymal stem cell exosome hydrogel targeting HIF-1α to improve microvascular in the treatment of diabetic foot ulcer
翁于格(1998.10-),女,海南医科大学临床医学院2023级皮肤病与性病学专业在读硕士研究生;研究方向:自身免疫性疾病和皮肤创伤愈合。
[通讯作者] 丁艳(1978.4-),女,博士,主任医师,博士生导师,海南省第五人民医院党委书记;研究方向:自身免疫性疾病和皮肤创伤愈合。
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