Applewhite Brandon, Gupta Aavni, Wei Yuntao, Yang Xiaofeng, Martinez Laisel, Rojas Miguel G, Andreopoulos Fotios, Vazquez-Padron Roberto I
Department of Biomedical Engineering, University of Miami, Coral Gables, FL, United States.
Department of Surgery, University of Miami Miller School of Medicine, Miami, FL, United States.
Front Cardiovasc Med. 2023 Feb 28;10:1124106. doi: 10.3389/fcvm.2023.1124106. eCollection 2023.
Arteriovenous fistula (AVF) postoperative stenosis is a persistent healthcare problem for hemodialysis patients. We have previously demonstrated that fibrotic remodeling contributes to AVF non-maturation and lysyl oxidase (LOX) is upregulated in failed AVFs compared to matured. Herein, we developed a nanofiber scaffold for the periadventitial delivery of β-aminopropionitrile (BAPN) to determine whether unidirectional periadventitial LOX inhibition is a suitable strategy to promote adaptive AVF remodeling in a rat model of AVF remodeling.
Bilayer poly (lactic acid) ([PLA)-]- poly (lactic-co-glycolic acid) ([PLGA)] scaffolds were fabricated with using a two-step electrospinning process to confer directionality. BAPN-loaded and vehicle control scaffolds were wrapped around the venous limb of a rat femoral-epigastric AVF during surgery. AVF patency and lumen diameter were followed monitored using Doppler ultrasound surveillance and flow was measured before euthanasia. AVFs were harvested after 21 days for histomorphometry and immunohistochemistry. AVF compliance was measured using pressure myography. RNA from AVF veins was sequenced to analyze changes in gene expression due to LOX inhibition.
Bilayer periadventitial nanofiber scaffolds extended BAPN release compared to the monolayer design ( < 0.005) and only released BAPN in one direction. Periadventitial LOX inhibition led to significant increases in AVF dilation and flow after 21 days. Histologically, BAPN trended toward increased lumen and significantly reduced fibrosis compared to control scaffolds ( < 0.01). Periadventitial BAPN reduced downregulated markers associated with myofibroblast differentiation including SMA, FSP-1, LOX, and TGF-β while increasing the contractile marker MYH11. RNA sequencing revealed differential expression of matrisome genes.
Periadventitial BAPN treatment reduces fibrosis and promotes AVF compliance. Interestingly, the inhibition of LOX leads to increased accumulation of contractile VSMC while reducing myofibroblast-like cells. Periadventitial LOX inhibition alters the matrisome to improve AVF vascular remodeling.
动静脉内瘘（AVF）术后狭窄是血液透析患者持续面临的医疗问题。我们之前已经证明，纤维化重塑会导致AVF未成熟，并且与成熟的AVF相比，失败的AVF中赖氨酰氧化酶（LOX）上调。在此，我们开发了一种用于外膜周围递送β-氨基丙腈（BAPN）的纳米纤维支架，以确定单向外膜周围抑制LOX是否是促进AVF重塑大鼠模型中适应性AVF重塑的合适策略。
采用两步电纺工艺制备具有方向性的双层聚乳酸（[PLA]）-聚乳酸-乙醇酸共聚物（[PLGA]）支架。在手术过程中，将负载BAPN的支架和载体对照支架包裹在大鼠股-腹壁AVF的静脉段周围。使用多普勒超声监测AVF的通畅情况和管腔直径，并在安乐死之前测量血流量。21天后收获AVF，进行组织形态计量学和免疫组织化学分析。使用压力肌动描记法测量AVF的顺应性。对AVF静脉的RNA进行测序，以分析由于LOX抑制导致的基因表达变化。
与单层设计相比，双层外膜周围纳米纤维支架延长了BAPN的释放时间（<0.005），并且仅在一个方向上释放BAPN。外膜周围抑制LOX导致21天后AVF扩张和血流量显著增加。组织学上，与对照支架相比，BAPN使管腔有增大趋势且纤维化显著减少（<0.01）。外膜周围BAPN降低了与肌成纤维细胞分化相关的下调标志物，包括平滑肌肌动蛋白（SMA）、成纤维细胞特异性蛋白1（FSP-1）、LOX和转化生长因子-β（TGF-β），同时增加了收缩标志物肌球蛋白重链11（MYH11）。RNA测序揭示了基质体基因的差异表达。
外膜周围给予BAPN治疗可减少纤维化并促进AVF顺应性。有趣的是，抑制LOX会导致收缩性血管平滑肌细胞（VSMC）积累增加，同时减少肌成纤维细胞样细胞。外膜周围抑制LOX会改变基质体，以改善AVF血管重塑。
