Rapid developments in stem cell research in recent years have provided a solid foundation for their use in medicine. Over the last few years, hundreds of clinical trials have been initiated in a wide panel of indications. Disorders and injuries of the nervous system still remain a challenge for the regenerative medicine. Neural stem cells (NSCs) are the optimal cells for the central nervous system restoration as they can differentiate into mature cells and, most importantly, functional neurons and glial cells. However, their application is limited by multiple factors such as difficult access to source material, limited cells number, problematic, long and expensive cultivation in vitro, and ethical considerations. On the other hand, according to the available clinical databases, most of the registered clinical trials involving cell therapies were carried out with the use of mesenchymal stem/stromal/signalling cells (MSCs) obtained from afterbirth or adult human somatic tissues. MSCs are the multipotent cells which can also differentiate into neuron-like and glia-like cells under proper conditions in vitro; however, their main therapeutic effect is more associated with secretory and supportive properties. MSCs, as a natural component of cell niche, affect the environment through immunomodulation as well as through the secretion of the trophic factors. In this review, we discuss various therapeutic strategies and activated mechanisms related to bilateral MSC–NSC interactions, differentiation of MSCs towards the neural cells (subpopulation of crest-derived cells) under the environmental conditions, bioscaffolds, or co-culture with NSCs by recreating the conditions of the neural cell niche.

Introduction: One of the key factors that may influence the therapeutic potential of mesenchymal stem/stromal cells (MSCs) is their metabolism. The switch between mitochondrial respiration and glycolysis can be affected by many factors, including the oxygen concentration and the spatial form of culture. This study compared the metabolic features of adipose-derived mesenchymal stem/stromal cells (ASCs) and dedifferentiated fat cells (DFATs) cultivated as monolayer or spheroid culture under 5% O₂ concentration (physiological normoxia) and their impact on MSCs therapeutic abilities. Results: We observed that the cells cultured as spheroids had a slightly lower viability and a reduced proliferation rate but a higher expression of the stemness-related transcriptional factors compared to the cells cultured in monolayer. The three-dimensional culture form increased mtDNA content, oxygen consumption rate (OCR) and extracellular acidification rate (ECAR), especially in DFATs-3D population. The DFATs spheroids also demonstrated increased levels of Complex V proteins and higher rates of ATP production. Moreover, increased reactive oxygen species and lower intracellular lactic acid levels were also found in 3D culture. Conclusion: Our results may suggest that metabolic reconfiguration accompanies the transition from 2D to 3D culture and the processes of both mitochondrial respiration and glycolysis become more active. Intensified metabolism might be associated with the increased demand for energy, which is needed to maintain the expression of pluripotency genes and stemness state.

Currently, the number of stem-cell based experimental therapies in neurological injuries and neurodegenerative disorders has been massively increasing. Despite the fact that we still have not obtained strong evidence of mesenchymal stem/stromal cells’ neurogenic effectiveness in vivo, research may need to focus on more appropriate sources that result in more therapeutically promising cell populations. In this study, we used dedifferentiated fat cells (DFAT) that are proven to demonstrate more pluripotent abilities in comparison with standard adipose stromal cells (ASCs). We used the ceiling culture method to establish DFAT cells and to optimize culture conditions with the use of a physioxic environment (5% O₂). We also performed neural differentiation tests and assessed the neurogenic and neuroprotective capability of both DFAT cells and ASCs. Our results show that DFAT cells may have a better ability to differentiate into oligodendrocytes, astrocytes, and neuron-like cells, both in culture supplemented with N21 and in co-culture with oxygen–glucose-deprived (OGD) hippocampal organotypic slice culture (OHC) in comparison with ASCs. Results also show that DFAT cells have a different secretory profile than ASCs after contact with injured tissue. In conclusion, DFAT cells constitute a distinct subpopulation and may be an alternative source in cell therapy for the treatment of nervous system disorders.

The heterogeneity of the mesenchymal stem/stromal cells (MSCs) population poses a challenge to researchers and clinicians, especially those observed at the population level. What is more, the lack of precise evidences regarding MSCs developmental origin even further complicate this issue. As the available evidences indicate several possible pathways of MSCs formation, this diverse origin may be reflected in the unique subsets of cells found within the MSCs population. Such populations differ in specialization degree, proliferation, and immunomodulatory properties or exhibit other additional properties such as increased angiogenesis capacity. In this review article, we attempted to identify such outstanding populations according to the specific surface antigens or intracellular markers. Described groups were characterized depending on their specialization and potential therapeutic application. The reports presented here cover a wide variety of properties found in the recent literature, which is quite scarce for many candidates mentioned in this article. Even though the collected information would allow for better targeting of specific subpopulations in regenerative medicine to increase the effectiveness of MSC-based therapies.

Energy metabolism homeostasis emerges as a dominant element influencing mesenchymal stem/stromal cells' trajectory of development. The predominant glycolysis activity is a primary driver of cell proliferation and maintenance of the high-energetic state. Here, we examined the functions of two crucial auxiliary pathways: the phosphate-pentose pathway (PPP) and fructose-2,6-biphosphate pathway (FBP) to evaluate their impact on the therapeutic potential of Adipose-Derived Stem/Stromal cells (ASCs) during prolonged culture in various oxygen conditions: 5 % O₂ - physiological normoxia or 21 % O₂ - atmospheric oxygen. Our findings demonstrate that ASCs cultured in 5 % O₂ increased the rate of proliferation, migration, and expression of stemness factors, which is prominent during the initial and middle passages. Additionally, ASCs cultured in a 5 % O₂ exhibited heightened protection mechanisms against free radicals, increased LDH gene expression, and elevated extracellular acidification rate (ECAR). By estimating the HIF-1α level, we concluded that 5 % oxygen conditions were insufficient to induce a profound hypoxic state in ASCs. However, at the protein level, both the PPP and FBP pathways appeared to be more active in young (2-passage) cells, regardless of oxygen conditions, and their activity diminished over time. Additionally, the chemical suppression of G6PDH by Polydatin and inhibition of PFKFB3 by PFK-158 in ASCs (passage-2) revealed dose- and time-dependent effect on decreasing migratory capabilities of cells. Nevertheless, our work underscores the adaptable nature of ASC metabolism to prevailing external conditions, with the aging of the culture contributing to the decline in glycolysis-associated auxiliary pathways.

Treatment of hard-to-heal, chronic wounds, particularly in palliative patients or in intensive care units, constitutes a significant issue. Due to the constant development in this field of medicine and numerous scientific reports, it is possible to use a variety of techniques and dressings in the difficult-to-heal wound treatment. However, a promising strategy and an alternative to conventional dressings may be the transplantation of cell-coated bio-scaffolds into the wound. In addition to keratinocytes or fibroblasts transplants, which show promising healing effects during scarring, an interesting solution seems to be the use of multipotent mesenchymal stem/stromal cells, for instance, those derived from the adipose tissue (ASCs). Stem/stromal cell therapy presents a variety of benefits e.g., the isolation itself is simple, has minimal side effects, and any adipose tissue in an adult body may be the source of the cells. The presence of stem/stromal cells at the site of skin damage not only stimulates their proliferation or migration, but also their differentiation into other necessary cell types and continuous recovery at the site of a chronic wound. ASCs are also characterized by high paracrine activity, they are capable of secreting many growth factors, cytokines, and extracellular vehicles (EVs) to the external wound environment. They may also stimulate cell-to-cell interactions and improve the survival of resident cells. The multitude of mechanisms which can promote stem/stromal cells at the site of a chronic wound may potentially lead to more effective repair and regeneration processes and ultimately faster recovery. However, cell therapy requires detailed further research, in particular clinical trials, in order to assess the practicality and cost-effectiveness of this application in clinical environments and in hospital wards.