The article discusses the stages of the formation and development of regenerative biomedicine as a science, as well as the prospects for its development. Regenerative biomedicine is based on the cell theory formulated in the 19th century and the stem cell theory formulated in the 20th century. The 21st century has seen a rapid development of gene and cell technologies, which allow us to explore the mechanisms of the continuous renewal of the cellular composition of organs and tissues, as well as the processes of their restoration after various types of damage, and to develop treatment methods based on these mechanisms. The use of regenerative medicine methods has results that are fundamentally different from those of classical medicine — they restore the normal structure and functional activity of organs and tissues damaged by injury or disease as much as possible. The body’s cellular composition is repeatedly renewed throughout life. Managing this process is the main promising tool for regenerative medicine.

The results of the VI National Congress on Regenerative Medicine held on November 13–15, 2024 in St. Petersburg are summarized. The main topics of the scientific program of the Congress were: discussion of the mechanisms of cell renewal in the body, regulation of repair and regeneration processes of organs and tissues, consideration of the tasks and successes of cell therapy and tissue engineering, presentation of the results of advanced research in the field of gene therapy and genome editing, discussion of ethical and legal regulation in regenerative medicine, as well as the most important issues of development, production and implementation of platforms and technologies for regenerative medicine. The event was attended 1,235 specialists. Scientific program of the Congress included 10 plenary reports, more than 145 reports at 18 symposia, 3 industrial symposia, 2 round tables and 345 poster reports. During the Congress, the participants were able to discuss the most important issues in this area, assess current trends and outline further development paths.

Regenerative endodontics is a strategy aimed at the regeneration of dental pulp or at least the formation of pulp-like tissue, ideally the pulp-dentin complex; regeneration of damaged coronal dentin, resorbed root, cervical or apical dentin. Regenerative endodontic strategies include stem cell transplantation and regenerative endodontic procedures (REP). REP methods are currently used in the endodontic treatment of open-apice teeth in patients aged 7–10 years. The most likely outcome of this treatment is repair (“maturation”) of the root, rather than regeneration of its tissues.
Aim of the study: to develop the method and evaluate the efficacy of dental pulp stem cells in combination with fibrin gel for regenerative endodontic treatment of mature permanent teeth in a large animal model.
Materials and methods. The study was conducted on minipigs. While under general anesthesia (xylazine and tiletamine-zolazepam), the animals underwent an X-ray examination of their oral cavities. This examination was performed to select a tooth that most closely resembled a human tooth in terms of its position in the jaw arch, as well as the number and shape of its roots and canals. The first left two-rooted molar (P2) was selected. The crown pulp was amputated, and the root pulp was extirpated. The canals were then filled with fibrin gel containing allogeneic pig dental stem cells. The gel was mixed with fibrinogen polymerization catalysts ( thrombin and calcium chloride) immediately before being injected into the canals for polymerization. Thus, the gel (3 μL, containing 15,000–18,000 cells per canal) took the shape of the canal during polymerization. Next, the gel was isolated with mineral trioxide aggregate, and the crown was filled with chemically cured, reinforced, packable glass ionomer cement. Four months after the endodontic treatment, the tooth was removed, fixed, decalcified, and used for a standard histological examination. Stepwise serial sections, 3–5 μm thick, were prepared and stained with hematoxylin and eosin. For quantitative assessment, seven sections were selected at different levels with a step of 10 μm, the images were scanned, and morphometric calculations were performed. Absolute and relative values of lengths and areas were assessed, as well as the degree of vascularization.
Results. The length, shape and volume of the root canals of the first left premolar (P2) are similar to those in humans, which allowed us to use approaches and equipment developed for the endodontic treatment of human teeth, thus increasing the relevance of the model. Histological sections in the apical part of the canal showed the formation of vascularized pulp-like stromal tissue, and in the middle and apical thirds of the root, areas with a palisade layer of cylindrical cells — active odontoblasts producing dentin — were detected next to basophilic masses. There were no inflammatory processes in the periapical area of the endodontically treated tooth. No changes in the animals’ well-being or eating behavior were observed.
Conclusion. The results of the pilot study indicate the prospects for the development of regenerative endodontics methods for the treatment of mature permanent teeth with formed roots. Scaffolds based on fibrin gel and dental pulp stem cells are generally suitable for the purposes of regenerative endodontics, but the method needs to be further improved to form pulp architectonics.

The aim of this work was to develop and optimize methods for obtaining and culturing human endometrial epithelial cells from a non-invasive source — menstrual blood. The study aims to create personalized in vitro endometrial models to study embryo implantation mechanisms, search for markers of endometrial receptivity, and develop new approaches to treat gynecological diseases, including infertility.
Methods. Menstrual blood collected from healthy donors was used to obtain endometrial cells. Endometrial fragments were isolated by filtration and enzymatic treatment. Cell culture was carried out under various conditions: as a monolayer (2D), tissue culture and organoids (3D). Immunocytochemical staining for the markers cytokeratin and E-cadherin was used to confirm the epithelial phenotype. To investigate endocytosis of the epidermal growth factor receptor ( EGFR) in tissue culture, fluorescence-labeled EGF was used.
Results. Menstrual blood has been shown to be an affordable source for producing viable endometrial cells. The resulting endometrial tissue culture preserves tissue architecture and can serve as a model for the study of endocytosis of the epidermal growth factor receptor ( EGFR). Cultivation of endometrial epithelium cells in the form of organoids made it possible to preserve the epithelial phenotype and proliferative activity of cells for a long time. Organoids demonstrated the ability to self-organize and form single-layer cell structures, which confirms their suitability for modeling the processes occurring in the endometrium in vivo. At the same time, cultivation under 2D conditions led to rapid aging of cells and loss of their functional properties.
Conclusion. The developed methods for culturing endometrial epithelial cells in the form of tissue culture and organoids open up new possibilities for studying the mechanisms of embryo implantation and searching for markers of endometrial receptivity. The findings have important implications for the development of personalized medicine, in particular for improving the effectiveness of assisted reproductive technology (ART) programs and developing new therapeutic approaches for the treatment of gynecological diseases.