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The state of rat kidneys after injection of bone marrow multipotent stromal cells (MSC) labeled with Vybrant CM-Dil into intact or resected liver was studied by fluorescence microscopy. The main structural changes in the kidneys after MSC injection into intact and partially resected liver manifested as granular dystrophy and necrobiotic/necrotic changes in single epithelial cells of the distal tubules and collecting ducts, thrombosis of some vessels, progression of an ascending urinary tract infection (detection of dust-like fluorescent objects), which can be due to the immunomodulating or even immunosuppressive influence of MSC and their detritus. MSC injected into the intact or resected liver, as well as the products of their degradation were not detected in the kidneys at all terms of observation. After injection of MSC into partially resected liver, manifestations of bacterial contamination of the renal medulla appeared later. The injection of MSC into the liver can be complicated by thrombosis of the renal vessels, which should be taken into account when using this administration route in the cell therapy., (© 2023. Springer Science+Business Media, LLC, part of Springer Nature.)

Based on the literary analysis, the influence of cellular technologies on the results of implantation of mesh materials was studied. The scientific literature of recent years contains a large amount of data devoted to the study of mesh structures and the possibilities of their modification using multipotent stromal cells (MSC) for implantation into patients for correcting tissue defects and pelvic organ prolapse. However, the ideal implant has not yet been created. Additional studies with a longer follow-up period are needed to determine the most successful and safe methods and materials for the restoration of pathologically altered or lost tissues and the transition to clinical trials. It is also yet to come to an unambiguous understanding of the best sources of MSC, ways for stimulation of proliferation, preservation and delivery of these cells into the necessary tissues of the body, to thoroughly study the causes of inefficiency and the risks of developing various complications, especially in the long term. The progress of urological implantology in modern conditions, of course, will be associated with the introduction of modern materials and technologies, including the using MSC.

The processes developing in various rat tissues after implantation of polymeric polyhydroxyalkanoate (PHA) film fragments with adsorbed autologous multipotent stromal (mesenchymal) cells of bone marrow origin (AMMSCBM), were studied by methods of light microscopy. After the implantation of PHA film with AMMSCBM, the number of blood vessels in the surrounding tissues was found to increase as a result of neoangiogenesis. In this case,AMMSCBM did not migrate and were not destroyed at the place of injection, but differentiated into the cells forming blood vessel structures. The processes of angiogenesis in the tissues around PHA implant, in turn, lead to development of a larger number of blood vessels in the granulations formed around the implanted foreign body, higher volume of granulations proper and subsequent development of a thicker capsule delimiting polymer implant.

Using the methods of luminescent microscopy, the results of injection of autologous multipotent stromal (mesenchymal) stem cells of bone marrow origin (SSCBMO) containing GFP gene, into thrombosed hindlimb vein were studied in 226 male Wag rats. It was found that the restoration of blood flow through the thrombosed main vein was not always the result of thrombolysis. No signs of incorporation of injected SSCBMO into the wall of thrombosed vessel, clot recanalization or collateral formation were detected. In experimental thrombosis model with thrombin administration and main vein ligation, the thrombosis of its small branches also took place. The restoration of blood flow occured via either blood clot recanalization or obliteration of thrombosed vessels and the outgrowth of the new ones. SSCBMO were found to participate in both of these processes resulting in faster restoration of a blood flow in the tissue microregion of thrombosed vein. Gradually the injected SSCBMO and the structures formed with their participation, were replaced by the own cells of a recipient organism.