Material-associated bone resorption

A number of similar macrophage responses to the implantation of various osteoplastic materials into bone defects in humans and laboratory animals have been demonstrated in the present article based on the retrospective analysis of the archival histological material (2008–2016). The presence of osteoplastic materials in a bone regenerate has led to the emergence of giant cells of foreign bodies and osteoclastogenic cells both on the surface of the material and neoformed bone with its subsequent resorption. It was suggested to name this phenomenon “material-associated bone resorption”. © 2019, Privolzhsky Research Medical University. All rights reserved

Matrices for Tissue Engineering Based on Ultrafine Fibers and Microparticles of Poly(hydroxybutyrate)

Abstract: The structure and diffusion properties of combined ultrafibrous matrices containing microspheres for prolonged release of lysozyme are studied in the work. The matrices are biocompatible and they are not cytotoxic. The matrices are obtained via electrospinning. These materials are suitable for solving problems of tissue engineering, since they combine ultrafine fibers of poly(hydroxybutyrate) promoting effective attachment and growth of cells and poly(hydroxybutyrate) microparticles capable of prolonged release of a bioactive compound. These properties allow one to recommend these matrices for tissue engineering. © 2021, Pleiades Publishing, Ltd

Developing Techniques of Acoustic Microscopy for Monitoring Processes of Osteogenesis in Regenerative Medicine

Abstract: High-resolution ultrasonic imaging techniques are necessary for the non-invasive diagnostics of artificial cell-matrix systems. The results from experimental studies show these techniques are sensitive to variations in the elastic properties of biopolymer samples and can be used effectively to detect micro and macro voids and monitor processes of biodegradation in tissue-engineered constructs (TECs). © 2020, Allerton Press, Inc

РАЗРАБОТКА ТКАНЕИНЖЕНЕРНОИ ТЕРАПЕВТИЧЕСКОЙ СИСТЕМЫ НА ОСНОВЕ ГИБРИДНОИ КОНСТРУКЦИИ ИЗ ПОЛИ-3-ОК-СИБУТИРАТА С ГИДРОКСИАПАТИТОМ, ЗАПОЛНЕННОЙ АЛЬГИНАТНЫМ ГИДРОГЕЛЕМ, СОДЕРЖАЩИМ МЕЗЕНХИМАЛЬНЫЕ СТВОЛОВЫЕ КЛЕТКИ

The purpose of this study was the development of three-dimensional hybrid tissue-engineered construct based on poly-3-oxybutyrate and mesenchymal stem cells for the replacement of bone defects. Regeneration of bone defects was studied on the model of the critical bone defect of the cranial vault in rats. To restore them, three-dimensional tissue-engineered construct (TEC) were manufactured on the basis of a composite of poly-3-oxybutyrate (POB) and nanosized hydroxyapatite (HAp): with a 3D printer a mold was printed, where a scaffold was formed using a double leaching methodfrom a POB /HAp composite. On the basis of the obtained scaffold, TEC was formed by filling it with sodium alginate solution (ALG) and mesenchymal stem cells (MSC) suspended therein, followed by its gelation. After TEC was placed in a critical bone defect, the dynamics and the parameters of regeneration was studied. After one month implantation results, namely, osteogenic activity, were determined using cone-beam tomography and histomorphome-try. The conducted studies showed that the developed by us TEC has osteogenic properties and promotes the regeneration of flat bones of the rats skulls. Implantation of TEC provides closure of the critical bone defect of the cranial vault in the rat to 92% of its area during 1 month of observation, presumably due to the introduced scaffold into the design of MSCs and biomaterials, capable of stimulating bone growth. Thus, the developed tissue-engineered construct possesses osteogenic properties, potentiating the regeneration of critical bone defects of the cranium of rat skull.Целью данного исследования явилась разработка трёхмерных гибридных тканеинженерных конструкций (ТИК) на основе поли-3-оксибутирата (ПОБ) и мезенхимальных стволовых клеток (МСК) для замещения костных дефектов. Регенерацию костных дефектов изучали на модели критического костного дефекта свода черепа у крыс. Для их восстановления были изготовлены трехмерные тканеинженерные конструкции на основе композита поли-3-оксибутирата и наноразмерного гидрок-сиапатита (ГАП): при помощи 3D-принтера была напечатана пресс-форма, в которой методом двойного выщелачивания из композита ПОБ/ГАП был сформирован скаффолд. На основе полученного скаффолда сформировали ТИК, заполнив ее раствором альгината натрия (АЛГ) и суспензированными в нем мезенхимальными стволовыми клетками с последующим его гелированием. ТИК помещали в критический костный дефект и исследовали динамику, а также параметры регенерации. Результаты имплантации, а именно остеогенную активность определяли через месяц с использованием конусно-лучевой томографии и методом гистоморфометрии. Проведенные исследования показали, что разработанная нами ТИК обладает остеогенными свойствами и способствует регенерации плоских костей черепа у крыс. Имплан-тациия ТИК обеспечивает закрытие критического костного дефекта свода черепа у крысы до 92% его площади в течение 1 месяца наблюдений, по-видимому, благодаря введенным в конструкцию МСК и биоматериалам скаффолда, способным к стимуляции роста костной ткани. Таким образом, разработанная тканеинженерная конструкция обладает остеогенными свойствами, потенции-руя регенерацию критических костных дефектов свода черепа крыс

Microcapsules of poly(3-hydroxybutyrate) for sustained protein release

The aim of investigation was to develop a system for protein sustained release based on the use of poly(3-hydroxybutyrate) (PHB) microcapsules loaded with bovine serum albumin (BSA). Materials and Methods. To develop microcapsule we used PHB obtained microbiologically by a strain-producer Azotobacter chroococcum 7B. Microcapsules loaded with model protein BSA were produced by double emulsion technique.“water/oil/water” Morphology of microcapsules was investigated by methods of confocal and scanning electron microscopy, when the loading and release of BSA was examined spectrophotometrically. In vivo biocompatibility of microcapsules was studied in accordance with intramuscular implantation and histology findings. Results. The study of BSA incorporation and its sustained release from microcapsules for more than 190 h demonstrated the efficacy of proposed system. The mechanism of protein release was found to occur due to the rupture of polymer walls. Moderate tissue response to the implantation of obtained microcapsules was demonstrated. Conclusion. Developed PHB microcapsules loaded with BSA are good model of long acting protein drugs. © 2015, Nizhny Novgorod State Medical Academy. All rights reserved

Microcapsules of poly(3-hydroxybutyrate) for sustained protein release

The aim of investigation was to develop a system for protein sustained release based on the use of poly(3-hydroxybutyrate) (PHB) microcapsules loaded with bovine serum albumin (BSA). Materials and Methods. To develop microcapsule we used PHB obtained microbiologically by a strain-producer Azotobacter chroococcum 7B. Microcapsules loaded with model protein BSA were produced by double emulsion technique.“water/oil/water” Morphology of microcapsules was investigated by methods of confocal and scanning electron microscopy, when the loading and release of BSA was examined spectrophotometrically. In vivo biocompatibility of microcapsules was studied in accordance with intramuscular implantation and histology findings. Results. The study of BSA incorporation and its sustained release from microcapsules for more than 190 h demonstrated the efficacy of proposed system. The mechanism of protein release was found to occur due to the rupture of polymer walls. Moderate tissue response to the implantation of obtained microcapsules was demonstrated. Conclusion. Developed PHB microcapsules loaded with BSA are good model of long acting protein drugs. © 2015, Nizhny Novgorod State Medical Academy. All rights reserved

Biocompatibility and Bioresorption of 3D-Printed Polylactide and Polyglycolide Tissue Membranes

We studied biocompatibility and bioresorption of 3D-printed polylactide and polyglycolide tissue membranes. Ultrasound microscopy and histological examination showed that membranes fabricated of a copolymer of lactic and glycolic acids in a mass ratio of 1:9 are bioresorbed and have good biocompatibility with soft tissues (connective tissue, adipose tissue, and epithelium). An important feature of the copolymer membranes, which differs them from pure polylactide membranes, is the formation of a thin fibrous capsule that did not interfere its destruction by the mechanism of hydrolytic resorption. © 2021, Springer Science+Business Media, LLC, part of Springer Nature