Репозиторий Университета

© 2019 Wolters Kluwer Health, Inc. Purpose of reviewThe current review summarizes contemporary decellularization and hydrogel manufacturing strategies in the field of tissue engineering and regenerative medicine.Recent findingsDecellularized extracellular matrix (ECM) bioscaffolds are a valuable biomaterial that can be purposed into various forms of synthetic tissues such as hydrogels. ECM-based hydrogels can be of animal or human origin. The use of human tissues as a source for ECM hydrogels in the clinical setting is still in its infancy and current literature is scant and anecdotal, resulting in inconclusive results.SummaryThus far the methods used to obtain hydrogels from human tissues remains a work in progress. Gelation, the most complex technique in obtaining hydrogels, is challenging due to remarkable heterogeneity of the tissues secondary to interindividual variability. Age, sex, ethnicity, and preexisting conditions are factors that dramatically undermine the technical feasibility of the gelation process. This is contrasted with animals whose well defined anatomical and histological characteristics have been selectively bred for the goal of manufacturing hydrogels.

© The Author(s) 2018. Objective: Chondrospheres represent a variant of tissue spheroids biofabricated from chondrocytes. They are already being used in clinical trials for cartilage repair; however, their biomechanical properties have not been systematically investigated yet. The aim of our study was to characterize chondrospheres in long-term in vitro culture conditions for morphometric changes, biomechanical integrity, and their fusion and spreading kinetics. Results: It has been demonstrated that the increase in chondrospheres secant modulus of elasticity is strongly associated with the synthesis and accumulation of extracellular matrix. Additionally, significant interplay has been found between biomechanical properties of tissue spheroids and their fusion kinetics in contrast to their spreading kinetics. Conclusions: Extracellular matrix is one of the main structural determinants of chondrospheres biomechanical properties during chondrogenic maturation in vitro. The estimation of tissue spheroids’ physical behavior in vitro prior to operative treatment can be used to predict and potentially control fusogenic self-assembly process after implantation in vivo.

© 2018, Nizhny Novgorod State Medical Academy. All rights reserved. The aim of the study was to demonstrate a good diagnostic potential of atomic force microscopy (AFM) in tracking morphological changes in the extracellular matrix (ECM) of connective tissue due to pathological processes. Here we summarize our experience in AFM application in a number of biomedical studies on the connective tissue disease, both for the research and clinical purposes. Materials and Methods. Depending on the project application (experimental or clinical), the tissue specimens were harvested either from animals, or from patients in the course of their surgical treatment, or post mortem. AFM images of fixed tissue slices on glass slides were acquired with a Solver P47 AFM instrument (NT-MDT, Russia), in the semi-contact mode. For mechanical properties mapping, the images were acquired on air in the PeakForce Quantitative Nanomechanical Mapping mode (PeakForce QNM®), using a MultiMode 8 atomic force microscope (Bruker, USA). The regions of interest for scanning were selected in accordance with the histological assignments for the same sample, based on the view of a sample in the built-in optical microscope of the AFM instrument setup. To quantify the changes in the ECM morphology visualized by AFM imaging, we applied flicker-noise spectroscopy parameterization. Results. AFM has been shown to reveal visible deviations from the normal morphology of the ECM in diseased tissues. We found that AFM and related techniques are capable of tracking disease-related changes at different levels of collagen organization in the ECM. At the microscale, AFM may detect loosening and disorganization of collagen fibers (e.g., in a dysplastic process), or the opposite process of their packing into tight parallel bundles in a fibrotic process. AFM may also monitor the ratio between collagen and non-fibrous material of the ECM, for example, in inflammatory and neoplastic processes. At the level of collagen fibrils, AFM may reveal early signs of the matrix destruction and remodeling not visible at the microscopic level. The flicker-noise spectroscopy parameters provide quantification of the morphological changes visualized by AFM. The PeakForce QNM® and nanoindentation studies give a further insight into the state of ECM via tracking changes in the local mechanical and adhesive properties. All our AFM studies appeared in a good agreement with the histological findings and generally had a superior sensitivity to pathology-related ECM rearrangements. Conclusion. AFM may serve as a valuable complementary diagnostic tool for tracking pathological changes in the connective tissue.