Dokuchaeva Anna A, Mochalova Aleksandra B, Timchenko Tatyana P, Kuznetsova Elena V, Podolskaya Kseniya S, Pashkovskaya Oxana A, Filatova Natalya A, Vaver Andrey A, Zhuravleva Irina Yu
Institute of Experimental Biology and Medicine, E. Meshalkin National Medical Research Center of the RF Ministry of Health, 15 Rechkunovskaya St., Novosibirsk 630055, Russia.
Polymers (Basel). 2023 Nov 2;15(21):4304. doi: 10.3390/polym15214304.
Poly-ε-caprolactone ((1,7)-polyoxepan-2-one; PCL) is a biodegradable polymer widely used in various fields of bioengineering, but its behavior in long-term studies appears to depend on many conditions, such as application specificity, chemical structure, in vivo test systems, and even environmental conditions in which the construction is exploited in. In this study, we offer an observation of the remote outcomes of PCL tubular grafts for abdominal aorta replacement in an in vivo experiment on a rat model. Adult Wistar rats were implanted with PCL vascular matrices and observed for 180 days. The results of ultrasound diagnostics and X-ray tomography (CBCT) show that the grafts maintained patency for the entire follow-up period without thrombosis, leakage, or interruptions, but different types of tissue reactions were found at this time point. By the day of examination, all the implants revealed a confluent endothelial monolayer covering layers of hyperplastic neointima formed on the luminal surface of the grafts. Foreign body reactions were found in several explants including those without signs of stenosis. Most of the scaffolds showed a pronounced infiltration with fibroblastic cells. All the samples revealed subintimal calcium phosphate deposits. A correlation between chondroid metaplasia in profound cells of neointima and the process of mineralization was supported by immunohistochemical (IHC) staining for S100 proteins and EDS mapping. Microscopy showed that the scaffolds with an intensive inflammatory response or formed fibrotic capsules retain their fibrillar structure even on day 180 after implantation, but matrices infiltrated with viable cells partially save the original fibrillary network. This research highlights the advantages of PCL vascular scaffolds, such as graft permeability, revitalization, and good surgical outcomes. The disadvantages are low biodegradation rates and exceptionally high risks of mineralization and intimal hyperplasia.
聚己内酯（（1,7）-聚氧杂环庚烷-2-酮；PCL）是一种可生物降解的聚合物，广泛应用于生物工程的各个领域，但其在长期研究中的表现似乎取决于许多条件，如应用特异性、化学结构、体内测试系统，甚至是植入物所处的环境条件。在本研究中，我们在大鼠模型的体内实验中观察了用于腹主动脉置换的PCL管状移植物的远期结果。将成年Wistar大鼠植入PCL血管基质并观察180天。超声诊断和X射线断层扫描（CBCT）结果显示，移植物在整个随访期内保持通畅，无血栓形成、渗漏或中断，但在该时间点发现了不同类型的组织反应。到检查当天，所有植入物均显示在移植物管腔表面形成的增生性新内膜层上有融合的内皮单层覆盖。在包括无狭窄迹象的几个外植体中发现了异物反应。大多数支架显示有成纤维细胞的明显浸润。所有样本均显示内膜下磷酸钙沉积。通过对S100蛋白的免疫组织化学（IHC）染色和能谱分析（EDS），支持了新内膜深层细胞中的软骨样化生与矿化过程之间的相关性。显微镜检查显示，具有强烈炎症反应或形成纤维化包膜的支架即使在植入后180天仍保留其纤维结构，但有活细胞浸润的基质部分保留了原始的纤维网络。本研究突出了PCL血管支架的优点，如移植物通透性、血管再生能力和良好的手术效果。缺点是生物降解率低以及矿化和内膜增生的风险极高。
