Electrospun tissue-engineered grafts made of biodegradable materials have become a perspective search field in terms of vascular replacement, and more research is required to describe their in vivo transformation. This study aimed to give a detailed observation of hemodynamic and structural properties of electrospun, monolayered poly-ε-caprolactone (PCL) grafts in an in vivo experiment using a rat aorta replacement model at 10, 30, 60 and 90 implantation days. It was shown using ultrasound diagnostic and X-ray tomography that PCL grafts maintain patency throughout the entire follow-up period, without stenosis or thrombosis. Vascular compliance, assessed by the resistance index (RI), remains at the stable level from the 10th to the 90th day. A histological study using hematoxylin-eosin (H&E), von Kossa and Russell–Movat pentachrome staining demonstrated the dynamics of tissue response to the implant. By the 10th day, an endothelial monolayer was forming on the graft luminal surface, followed by the gradual growth and compaction of the neointima up to the 90th day. The intense inflammatory cellular reaction observed on the 10th day in the thickness of the scaffold was changed by the fibroblast and myofibroblast penetration by the 30th day. The cellularity maximum was reached on the 60th day, but by the 90th day the cellularity significantly (p = 0.02) decreased. From the 60th day, in some samples, the calcium phosphate depositions were revealed at the scaffold-neointima interface. Scanning electron microscopy showed that the scaffolds retained their fibrillar structure up to the 90th day. Thus, we have shown that the advantages of PCL scaffolds are excellent endothelialization and good surgical outcome. The disadvantages include their slow biodegradation, ineffective cellularization, and risks for mineralization and intimal hyperplasia.

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.

Polymer heart valves are a promising alternative to bioprostheses, the use of which is limited by the risks of calcific deterioration of devitalized preserved animal tissues. This is especially relevant in connection with the increasingly widespread use of transcatheter valves. Advances in modern organic chemistry provide a wide range of polymers that can replace biological material in the production of valve prostheses. In this work, the main properties of REPEREN^® polymer film, synthesized from methacrylic oligomers reinforced with ultra-thin (50 µm) polyamide fibers, are studied. The film structure was studied using scanning electron microscopy (SEM) and atomic force microscopy (AFM). The hydrophilicity and cytocompatibility with EA.hy926 endothelial cells were assessed, and a hemocompatibility evaluation was carried out by studying the platelet aggregation and adhesion upon contact of the REPEREN^® with blood. The mechanical behavior and biocompatibility (subcutaneous implantation in rats for up to 90 days, followed by a histological examination) were studied in comparison with a bovine pericardium (BP) cross-linked with an ethylene glycol diglycidyl ether (DE). The results showed that REPEREN^® films have two surfaces with a different relief, smooth and rough. The rough surface is more hydrophilic, hemo- and cytocompatible. Compared with the DE-BP, REPEREN^® has a higher ultimate tensile stress and better biocompatibility when implanted subcutaneously in rats. The key properties of REPEREN^® showed its potential for the development of a polymeric heart valve. Further studies should be devoted to assessing the durability of REPEREN^® valves and evaluating their function during orthotopic implantation in large animals.

Endovascular embolization using coils is a widely used method for treating various vascular pathologies. There are many types of coils, differing in design, material and technical characteristics, which allows choosing the best options depending on the clinical setting. The article discusses the main types of endovascular coils and their technical features. The final part presents cases of successful use of endovascular embolization coils and stopping bleeding, demonstrating its high potential and important role in modern interventional therapy.

Результаты эндоваскулярной реваскуляризации сочетанных поражений бифуркации аорты и подвздошных артерий в ближайшие и отдаленные периоды наблюдения

Chronic mesenteric ischemia (CMI) is an urgent public health problem. The long asymptomatic course of the disease, sudden onset and an unfavorable prognosis in the absence of treatment make it necessary to pay closer attention to this pathology. There are currently two competitive treatments for CMI: surgical and endovascular revascularization. Despite numerous studies comparing these methods, the question of which one is more effective and reliable remains open. The review includes current data from clinical trials and meta-analyses demonstrating the advantages and disadvantages of both methods.