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.

Screw metal implants (3S, Israel) with rough or smooth polished surface were introduced in a tibial proximal condyle of not purebred rabbits. The condition of surrounding tissues in 2 and 6 months after implantation was compared by light microscopy and X-ray methods. Within 6 months after operation the considerable distinctions of radiological and morphological data were revealed not. 2 months later after introduction of implants with a rough surface the effort enclosed for its twisting is, much more, than for removal of the polished product. However, stability of fixing of implants was practically made even at 6 months. On remote rough implants there is a set of tissue scraps whereas on products with a smooth surface the tissue remains were much less. Surrounding tissues strongly join a rough surface, grow into cavities, and during removal of such products there is a considerable trauma of tissues round an implantation place. Smooth implants have the smaller area of contact with organism tissues, they are fixed due to bicortical implantation, during removal easily get out and don't break off surrounding tissues. The signs of inflammation and formation of merged multinuclear macrophages were not found at all cases, which give evidence to the inertness of material of the mentioned articles for living organism. In some observations however and by implantation of the rough article and by introduction of polished implants, metal particles were found, but after use of the foreign body with grit-blasted treatment of surface metal was found more frequently, and its fragments had larger volume.M. S. Toder et al.

Herein, the aim was to study the state of the bone tissue adjacent to dental implants after the use of extracellular vesicles derived from multipotent stromal cells (MSC EVs) of bone marrow origin in the experiment. In compliance with the rules of asepsis and antiseptics under general intravenous anesthesia with propofol, the screw dental implants were installed in the proximal condyles of the tibia of outbred rabbits without and with preliminary introduction of 19.2 μg MSC EVs into each bone tissue defect. In 3, 7, and 10 days after the operation, the density of bone tissue adjacent to different parts of the implant using an X-ray unit with densitometer was measured. In addition, the histological examinations of the bone site with the hole from the removed device and the soft tissues from the surface of the proximal tibial condyle in the area of intra-bone implants were made. It was found out that 3 days after implantation with the use of MSC EVs, the bone density was statistically significantly higher by 47.2% than after the same implantation, but without the injection of MSC EVs. It is possible that as a result of the immunomodulatory action of MSC EVs, the activity of inflammation decreases, and, respectively, the degree of vasodilation in bones and leukocyte infiltration of the soft tissues are lower, in comparison with the surgery performed in the control group. The bone fragments formed during implantation are mainly consolidated with each other and with the regenerating bone. Day 10 demonstrated that all animals with the use of MSC EVs had almost complete fusion of the screw device with the bone tissue, whereas after the operation without the application of MSC EVs, the heterogeneous histologic pattern was observed: From almost complete osseointegration of the implant to the absolute absence of contact between the foreign body and the new formed bone. Therefore, the use of MSC EVs during the introduction of dental implants into the proximal condyle of the tibia of rabbits contributes to an increase of the bone tissue density near the device after 3 days and to the achievement of consistently successful osseointegration of implants 10 days after the surgery.

Материалы, используемые для изготовления дентальных имплантатов, должны обладать механической прочностью, высокой биосовместимостью, отсутствием биодеградации и в основном должны решать две задачи: улучшение интеграции инородных тел с живыми тканями организма и борьбу с периимплантной инфекцией. Обе неурегулированные проблемы могут стать причиной отторжения искусственных изделий. Для выявления современного положения дел по выбору материалов для изготовления дентальных имплантатов и приданию им антибактериальных свойств была изучена научная литература за последние 2 года. Принимая во внимание большое число разноречивых результатов исследований, посвященных каждой из проблем дентальной имплантации, можно сделать заключение, что ни одна из основных задач окончательно не решена. Продолжаются поиски материалов, которые взаимодействуют с биологическими тканями без развития сопутствующего воспалительного процесса. Также не закончены разработки методов, направленных на профилактику и борьбу с периимплантной инфекцией. Формирование костной ткани на границе имплантата, срастание его поверхности с костью, несомненно, является благоприятным признаком, свидетельствующим о стабильности установки изделия, долгосрочности его службы. Необходима тщательная обработка поверхности имплантатов для исключения попадания в ткани даже мельчайших его частиц, что может поставить под сомнение успешность самой процедуры дентальной имплантации. Целесообразно изготавливать все детали имплантата из одного материала для профилактики электрохимической коррозии изделий в тканях на границе различных металлов. Перспективно нанесение покрытия на дентальные имплантаты, которое не только обладает антимикробным свойством, но и улучшает процессы их остеоинтеграции. Также представляется эффективной активная или пассивная адсорбция бактериофага или смеси нескольких бактериофагов на поверхности имплантируемых материалов. Необходимо отметить, что качество изделий, внедряемых в организм, постоянно улучшается, постепенно совершенствуются их различные характеристики, что способствует повышению эффективности ближайших и отдаленных результатов хирургического вмешательства-дентальной имплантации. Ключевые слова: обзор литературы, дентальная имплантация, имплантируемые материалы, взаимодействие искусственных материалов с тканями организма, антибактериальные свойства имплантатов. The features of interaction between dental implants and organism tissues and the modern methods of creation of antibacterial covering on implant surfaces

Regeneration processes in rat mandibular bone after transplantation of a suspension of autologous BM MSC in culture medium were studied by methods of light microscopy and X-ray densitometry. It was found that the structures of red BM in the callus after transplantation of autologous BM MSC formed earlier than in natural reparation. The formation of cavities containing BM determines lower tissue density at the site of injury after transplantation of autologous BM MSC on weeks 4 and 5 of observation than during spontaneous healing. These changes progressed throughout the observation period and attested to accelerated bone tissue reparation.