Bone reconstruction techniques are mainly based on the use of tissue grafts and artificial scaffolds. The former presents well-known limitations, such as restricted graft availability and donor site morbidity, while the latter commonly results in poor graft integration and fixation in the bone, which leads to the unbalanced distribution of loads, impaired bone formation, increased pain perception, and risk of fracture, ultimately leading to recurrent surgeries. In the past decade, research efforts have been focused on the development of innovative bone substitutes that not only provide immediate mechanical support, but also ensure appropriate graft anchoring by, for example, promoting de novo bone tissue formation. From the countless studies that aimed in this direction, only few have made the big jump from the benchtop to the bedside, whilst most have perished along the challenging path of clinical translation. Herein, we describe some clinically successful cases of bone device development, including biological glues, stem cell-seeded scaffolds, and gene-functionalized bone substitutes. We also discuss the ventures that these technologies went through, the hindrances they faced and the common grounds among them, which might have been key for their success. The ultimate objective of this perspective article is to highlight the important aspects of the clinical translation of an innovative idea in the field of bone grafting, with the aim of commercially and clinically informing new research approaches in the sector.

Cryopreservation is the only established method to provide long-term storage and fast availability of cellular product for therapeutic applications. The overwhelming majority of cryopreservation media contain toxic concentrations of dimethyl sulfoxide (DMSO) limiting the possibility for the direct administration of cryopreserved cells to the patients. Here, we propose a novel approach for nontoxic xeno-free cryopreservation of human multipotent mesenchymal stromal cells (MSCs) aimed at ensuring high viability, ready-to-use availability, and localized delivery of the cell-based graft into damaged tissues. For MSC cryopreservation, we applied sucrose pretreatment procedure and xeno-free cryoprotective medium containing human platelet-poor blood plasma (PPP), sucrose, and nontoxic concentration of DMSO. Using the combination of PPP, 0.2 M sucrose, and 1% DMSO, the recovery rate of cryopreserved MSCs reached 73% of the values obtained for noncryopreserved cells. Moreover, the presence of PPP in the cryoprotective medium provided the possibility to create a ready-to-use 3D hydrogel for the localized delivery and additional support of MSCs in vivo. In a proof-of-concept study, we assessed the regenerative capacity of cryopreserved MSCs in a full-thickness wound model in mice. The positive impact of MSCs within 3D gel on wound healing rates was confirmed by morphometric and histological examinations. Our results demonstrate the possibility to apply cryopreserved cells immediately after thawing using a cryoprotective medium as the vehicle solution.

In current in vitro study we have shown the impact of deuterium content in growth medium on proliferation rate of human cultured adipose-derived stem cells (ADSC). ADSCs have also demonstrated morphological changes when cultured in deuterated growth medium: the cell cultures did not reach confluence but acquired polygonal morphology with pronounced stress fibers. At high deuterium concentrations the ADSCs population doubling time increased which indicated the cell cycle retardation and decrease of cell proliferation rate. The deuterated and deuterium-depleted growth media demonstrated acute and chronic cytotoxicity, respectively. The minimal migration ability was observed in deuterated medium whereas the highest migration activity was observed in the medium with the deuterium content close to natural. The cells in deuterated growth medium demonstrated decrease in metabolic activity after three days in culture. In contrast, in deuterium-depleted medium there was an increase in ADSC metabolic activity.

All living organisms have been evolutionarily adapted to natural water with 0.24 M constant ratio of hydrogen isotopes: protium and deuterium [3, 7]. Studies of physical and chemical properties of water with different ratio of hydrogen isotopes revealed abnormal phenomena in water with either reduced or increased deuterium content, associated with a huge isotopic effect [4, 10]. In organic chemical compounds within living tissues the deuterium water is more stable, and that is why it scarcely participates in metabolic processes and inhibits them [6, 9]. Protective properties of deuterium depleted water (DDW) are confirmed by findings in toxicological research. The DDW efficiently removes toxins and metabolic products out of body due to its transport properties [2, 5, 8]. Some features in dynamics of respiratory chain reactions in mitochondria were revealed at the molecular level when changing water isotope composition, i. e. a decrease in deuterium content in water down to the level below natural concentrations de-inhibited and accelerated the studied reaction [6, 8]. Proceeding from the stated above the role of deuterium in the in vitro biological systems has not been finally determined yet. In this context this research was aimed to study the effect of isotope composition of deuterium

Introduction. The adult neural crest-derived stem cells (NCSCs) have significant perspectives for use in regenerative medicine. The most attractive sources for adult NCSC isolation are the hair follicles (HF) and skin dermis (SD) because of easy access and minimally invasive biopsy. The aim of this study was to compare the biological properties of HF- and SD-derived NCSCs after their large-scale expansion. Methods. The conventional explant method was used to obtain HF NCSCs. For the isolation of SD NCSCs, a new combined technique consisting of preplating and subsequent culturing in 3D blood plasma-derived fibrin hydrogel was applied. The studied cells were characterized by flow cytometry, ICC, qPCR, Bio-Plex multiplex assay, and directed multilineage differentiation assays. Results. We have obtained both adult SD and HF NCSCs from each skin sample (n=5). Adult SD and HF NCSCs were positive for key neural crest markers: SOX10, P75 (CD271), NESTIN, SOX2, and CD349. SD NCSCs showed a higher growth rate during the large-scale expansion compared to HF NCSCs (p<0.01). Final population of SD NCSCs also contained more clonogenic cells (p<0.01) and SOX10+, CD271+, CD105+, CD140a+, CD146+, CD349+ cells (p<0.01). Both HF and SD NCSCs had similar gene expression profiling and produced growth factors, but some quantitative differences were detected. Adult HF and SD NCSCs were able to undergo directed differentiation into neurons, Schwann cells, adipocytes, and osteoblasts. Conclusion. The HF and SD are suitable sources for large-scale manufacturing of adult NCSCs with similar biological properties. We demonstrated that the NCSC population from SD was homogenous and displayed significantly higher growth rate than HF NCSCs. Moreover, SD NCSC isolation is cheaper, easier, and minimally time-consuming method.

Aim: The purpose of this work was to obtain, multiply and characterize the adult neural crest-derived multipotent stem cells from human hair follicle for their further clinical use. Materials and Methods: Adult neural crest-derived multipotent stem cells were obtained from human hair follicle by explant method and were expanded at large-scale up to a clinically significant number. The resulted cell cultures were examined by flow cytometry and immunocytochemical analysis. Their clonogenic potential, ability to self-renewal and directed multilineage differentiation were also investigated. Results: Cell cultures were obtained from explants of adult human hair follicles. Resulted cells according to morphological, phenotypic and functional criteria satisfied the definition of neural crest-derived multipotent stem cells. They had the phenotype Sox2+Sox10+Nestin+CD73+CD90+CD105+CD140a+CD 140b+CD146+CD166+CD271+CD349+ CD34-CD45-CD56-HLA-DR-, showed high clonogenic potential, ability to self-renewal and directed differentiation into the main derivatives of the neural crest: neurons, Schwann cells, adipocytes and osteoblasts. Conclusion: The possibility of a large-scale expansion of adult neural crest-derived multipotent stem cells up to 40–200·106 cells from minimal number of hair follicles with retention of their phenotype and functional properties are the significant step towards their translation into the clinical practice.

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In this study, we performed an adipogenic differentiation of human adipose-derived stem cells (ADSCs) in vitro with different deuterium content (natural, low and high) in the culture medium during differentiation process with parallel analysis of the gene expression, metabolic activity and cell viability/ toxicity. After ADSCs differentiation into adipocytes we have done the analysis of differentiation process efficiency and determined a type of resulting adipocytes (by morphology, gene expression, UCP1 protein detection and adipokine production analysis). We have found that high (5 × 10 5 ppm) deuterium content significantly inhibit in vitro adipogenic differentiation of human ADSCs compared to the groups with natural (150 ppm) and low (30 ppm) deuterium content. Importantly, protocol of differentiation used in our study leads to white adipocytes development in groups with natural (control) and high deuterium content, whereas deuterium-depleted differentiation medium leads to brown-like (beige) adipocytes formation. We have also remarked the direct impact of deuterium on the cellular survival and metabolic activity. Interesting, in deuterium depleted-medium, the cells had normal survival rate and high metabolic activity, whereas the inhibitory effect of deuterated medium on ADSCs differentiation at least was partly associated with deuterium cytotoxicity and inhibitory effect on metabolic activity. The inhibitory effect of deuterium on metabolic activity and the subsequent decrease in the effectiveness of adipogenic differentiation is probably associated with mitochondrial dysfunction. Thus, deuterium could be considered as an element that affects the substance chirality. These findings may be the basis for the development of new approaches in the treatment of obesity, metabolic syndrome and diabetes through the regulation of adipose-derived stem cell differentiation and adipocyte functions. In the 21st century, non-communicable diseases (NCD) like obesity, metabolic syndrome and type 2 diabetes mellitus (T2DM) became the main medical problems of the humanity 1-4. These diseases started in the Western world, but in parallel with the improving of human life standards, technological progress and the spread of the Western lifestyle also around the world. So, these diseases have become a global epidemic 5. Currently, although there remains a correlation between the level of economic development and the frequency of these diseases, they have ceased to be a medical problem in high-income countries, but also have become an urgent item for the low-income and middle-income countries 6. A characteristic feature of obesity, metabolic syndrome and T2DM is the defection of glucose and lipids metabolism, which is manifested in insulin resistance, impaired fasting glucose, dyslipidemia, high blood sugar, high serum triglycerides, imbalance of different types of lipoproteins in blood serum 7,8 .