The expression of Ki-67 proliferation marker was studied in vaginal biopsy specimens from women with stress urinary incontinence treated using a Fotona nonablative erbium laser. Cells expressing Ki-67 were located in all cases in the parabasal and basal levels of stratified squamous epithelium, the index of labeled nuclei before Er:YAG laser exposure was 19.05±2.86%. After 1-2 months of laser therapy, the index of labeled nuclei in the epithelium increased significantly and reached 31.79±2.25%. These changes were interpreted as a result of epithelial-stromal interactions. Presumably, the increase in proliferative activity of the vaginal epithelium after exposure to Er:YAG laser was due to the presence of an appreciable level of synthetically active fibroblasts in the subepithelial stroma.

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When administered intravenously, extracellular vesicles derived from multipotent stromal cells (MSC EVs) immediately pass through the lungs along with the blood and regularly spread to all organs. When administered intraperitoneally, they are absorbed either into the blood or into the lymph and are quickly disseminated throughout the body. The possibility of generalized spread of MSC EVs to distant organs in case of local intratissular administration remains unexplored. However, it is impossible to exclude MSC EV influence on tissues distant from the injection site due to the active or passive migration of these injected nanoparticles through the vessels. The research is based on findings obtained when studying the samples of lungs, heart, spleen, and liver of outbred rabbits of both sexes weighing 3–4 kg at various times after the injection of EVs derived from MSCs of bone marrow origin and labeled by PKH26 into an artificially created defect of the proximal condyle of the tibia. MSC EVs were isolated by serial ultracentrifugation and characterized by transmission electron microscopy and flow cytometry. After the introduction of MSC EVs into the damaged proximal condyle of the tibia of rabbits, these MSC EVs can be found most frequently in the lungs, myocardium, liver, and spleen. MSC EVs enter all of these organs with the blood flow. The lungs contained the maximum number of labeled MSC EVs; moreover, they were often associated with detritus and were located in the lumen of the alveoli. In the capillary network of various organs except the myocardium, MSC EVs are adsorbed by paravasal phagocytes; in some cases, specifically labeled small dust-like objects can be detected throughout the entire experiment—up to ten days of observation. Therefore, we can conclude that the entire body, including distant organs, is effected both by antigenic detritus, which appeared in the bloodstream after extensive surgery, and MSC EVs introduced from the outside.