Cell-based therapies using corneal stromal stem cells (CSSC), corneal keratocytes, or a combination of both suppress corneal scarring. The number of quiescent keratocytes in the cornea is small; it is difficult to expand them in vitro in quantities suitable for transplantation. This study examined the therapeutic effect of corneal fibroblasts reversed into keratocytes (rCF) in a mouse model of mechanical corneal injury. The therapeutic effect of rCF was studied in vivo (slit lamp, optical coherence tomography) and ex vivo (transmission electron microscopy and immunofluorescence staining). Injection of rCF into the injured cornea was accompanied by recovery of corneal thickness, improvement of corneal transparency, reduction of type III collagen in the stroma, absence of myofibroblasts, and the improvement in the structural organization of collagen fibers. TEM results showed that 2 months after intrastromal injection of cells, there was a decrease in the fibril density and an increase in the fibril diameter and the average distance between collagen fibrils. The fibrils were well ordered and maintained the short-range order and the number of nearest-neighbor fibrils, although the averaged distance between them increased. Our results demonstrated that the cell therapy of rCF from ReLEx SMILe lenticules promotes the recovery of transparent corneal stroma after injury.

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.

Relevance. Around the world, corneal blindness caused by impaired transparency is one of the leading causes of vision loss. Damage to the cornea can also lead to the development of opacities. The pathogenesis of corneal opacities is based on pathomorphological changes in the corneal stroma. To explore the therapeutic potential of biomedical products and develop new treatments, a standardized and reproducible in vivomodel of corneal stromal injury is needed. In experimental ophthalmology, mouse models of various corneal injuries are widely used, but the dynamics of posttraumatic restoration of the ultrastructural organization of the stroma have been little studied. Purpose. To evaluate structural and functional changes in the corneal stroma of mice in the dynamics of post-traumatic recovery. Material and methods. Injury to the corneal stroma was performed using a sharp 33G needle in the form of a tunnel defect in the thickness of the cornea of C57BL/6 mice. The presence of post-traumatic damage and the dynamics of corneal recovery were assessed using instrumental methods (biomicroscopy of the anterior segment of the eye with a fluorescein test, optical coherence tomography (OCT) before, immediately after the injury, and after 2 and 4 weeks after injury. Transmission electron microscopy was performed using a JEM 1400 electron microscope. Morphometry of digital images was performed using Image J software, calculating the minimum nearest interfibrillar distance, diameter and fibril density. Results. The formation of a corneal stromal wound was confirmed by the development of reactive edema according to OCT data and the accumulation of fluorescein in all damaged corneas. 2 weeks after the injury, complete epithelization of the wound surface was observed. According to OCT data, 2 weeks after the injury, an increase in corneal thickness by 34% and an increase in the opacity index by 1.5 times were recorded compared to a healthy cornea. By the 4th week of observation, the corneal thickness and opacity index remained at a high level in the injured cornea. After the formation of injury to the corneal stroma, a decrease in the diameter of collagen fibrils, an increase in fibril density and the shortest nearest interfibrillar distance were revealed throughout the observation period. onclusion. A mechanical model of corneal trauma performed using a sharp 33-gauge needle induces the formation of stable stromal opacities. Instrumental and morphological research methods did not reveal stromal restoration during the entire observation period (4 weeks). Key words: corneal trauma, optical coherence tomography, corneal thickness, corneal transparency, corneal morphology, corneal fibrils