Therapeutic efficacy of olfactory ensheathing cells and type I collagen administered separately or in combination was studied in a model of chronic spinal cord injury in rats. The introduction of collagen hydrogel at a concentration of 4 mg/ml with and without olfactory ensheathing cells into spinal cord cysts reduced cyst volume and restored hindlimb motor function. The introduction of collagen hydrogel at both concentrations (1 and 4 mg/ml) with and without ensheathing cells stimulated remyelination of damaged nerve tissue. The results show that further study of this bioengineered preparation, as well as other combinations with cells or hydrogels is promising for the treatment of spinal cord injuries.

Alzheimer’s disease was induced in female Wistar rats by bilateral injection of β-amyloid fragment 1-42 into the hippocampal region. After 8 weeks, ensheathing cells of the olfactory mucosa were transplanted into the hippocampus at the same stereotactic coordinates. These cells survived for 8 weeks; large clusters of cells were observed on week 4. On weeks 3-5 after transplantation of ensheathing cells, experimental animals demonstrated a significant cognitive improvement (memory and spatial orientation). The obtained results create prerequisites for further studies of ensheathing cells as a potential cell product for personalized therapy of Alzheimer’s disease.

A new gene-cell construct expressing nerve growth factor (NGF) has been developed. After obtaining engineered adenovectors Ad5-RGD-CAG-NGF and Ad5-RGD-CAG-EGFP, transduction efficiency and transgene expression were studied and multiplicity of infection was determined. The efficacy of transduced human olfactory ensheathing cells expressing NGF in restoring motor activity in rats has been shown in a limited period of time. Improved rat hindlimb mobility and cyst size reduction after gene-cell construct transplantation were more likely due to the cellular component of the construct.

The review considers the use of exogenous neurotrophic factors in the treatment of neurodegenerative diseases, such as Alzheimer’s disease, Parkinson’s disease, multiple sclerosis, and others. This group of diseases is associated with the death of neurons and dysfunction of the nervous tissue. Currently, there is no effective therapy for neurodegenerative diseases, and their treatment remains a serious problem of modern medicine. A promising strategy is the use of exogenous neurotrophic factors. Targeted delivery of these factors to the nervous tissue can improve survival of neurons during the development of neurodegenerative processes and ensure neuroplasticity. There are methods of direct injection of neurotrophic factors into the nervous tissue, delivery using viral vectors, as well as the use of gene cell products. The effectiveness of these approaches has been studied in numerous experimental works and in a number of clinical trials. Further research in this area could provide the basis for the creation of an alternative treatment for neurodegenerative diseases.

This paper shows for the first time that co-transplantation of human olfactory ensheathing cells with neurotrophin-3 into spinal cord cysts is more effective for activation of remyelination than transplantation of cells with brain-derived neurotrophic factor and a combination of these two factors. The studied neurotrophic factors do not affect proliferation and migration of ensheathing cells in vitro. It can be concluded that the maximum improvement of motor function in rats receiving ensheathing cells with neurotrophin-3 is largely determined by activation of remyelination.

We analyzed the main approaches to the modeling of Alzheimer’s disease for studying the effectiveness of cell therapy. Recent advances in regenerative medicine in the field of neuroscience create prospects for the use of various cell preparations for the treatment of Alzheimer’s disease. Experimental data on the use of neural stem/progenitor cells, mesenchymal stem cells, embryonic stem cells, and induced pluripotent stem cells in various models of Alzheimer’s disease are presented. Of particular importance is the standardization of protocols. The use of a standardized protocol in modeling of Alzheimer’s disease will allow a comparative analysis of the effectiveness and safety of treatment to identify the optimal cell preparation. The data obtained on experimental animals can form the basis for further preclinical and clinical studies of cell therapy for Alzheimer’s disease.

Alzheimer's disease was modeled in female Wistar rats aged 4 months by stereotaxic bilateral injection of a synthetic peptide β-amyloid (Aβ1-42) into the hippocampus. Behavioral tests (open field, Y-maze, passive avoidance, and Morris water maze) revealed significant impairment of memory and spatial navigation 8 weeks after β-amyloid administration. At this term, the cognitive impairments typical of Alzheimer's disease are reproduced. The experimental model of Alzheimer's disease proposed by us can be used in preclinical studies of drugs for the treatment of this pathology.

We studied the effect of exosomes derived from mesenchymal stem cells on the synthesis of collagen I and α-smooth muscle actin (α-SMA) by rat fibroblast culture. Exosomes were isolated from the verified culture of mesenchymal stem cells and also verified. Fibrosis was modeled using a fibroblast culture supplemented with recombinant TGF-β1 (5 ng/ml) and immunocytochemical analysis of the expression of collagen I and α-SMA markers was carried out. After 6-day incubation, the expression of the studied markers increased in comparison with the control. Addition of exosomes to the fibroblast culture reduced the production of collagen and SMA, which allows considering exosomes as a promising drug for the treatment of pathologies associated with fibrosis.

A gene-cell construct based on rat olfactory mucosa ensheathing cells transduced with an adenoviral vector encoding a mature form of brain neurotrophic factor (mBDNF) was transplanted into post-traumatic cysts of rat spinal cord. Transplantation of the gene-cell construct improved motor activity of the hind limbs and reduced the size of cysts in some animals. How-ever, comparison of the effects of transduced and non-transduced ensheathing cells revealed no significant differences. In parallel in vitro experiments, a decrease in the proliferation of transduced cells compared to non-transduced cells was observed. It is likely that mBDNF reduces proliferation of transduced cells, which can affect their efficiency. The therapeutic efficacy of the new gene-cell construct is most likely provided by the cellular component.

In this study, we identified the optimal time frame for the development of signs of beta-amyloid-induced Alzheimer's disease using behavioral tests. It was shown that significant cognitive impairments in males were observed 8 weeks after injection of the beta-amyloid peptide.

We developed a viral vector Ad5/35-CAG-mBDNF expressing the mature form of BDNF (mBDNF). On the basis of olfactory ensheathing cells transduced with this adenovector, a new gene-cell construct was obtained. In experiments in vitro, high viability of the transduced olfactory ensheathing cells and enhanced secretion of BDNF by these cells were observed. It is possible that a new gene-cell construct will significantly increase the regenerative effects of transplanted olfactory ensheathing cells.

The experimental post-traumatic spinal cord cysts were modeled. The efficiency of transplantation of the human olfactory ensheathing cells into cysts to restore the motor activity of the hind limbs of rats was shown. Survival and migration of ensheathing cells in vivo, their participation in the remyelination were shown.

Neurotrophin-3 enhances the effectiveness of human olfactory ensheathing cells in improving hind limb mobility in rats with post-traumatic cysts of the spinal cord. Transplantation of olfactory ensheathing cells into spinal cord cysts reduced their size; neurotrophin-3 did not modulate this effect. Combined preparation of human olfactory ensheathing cells and neurotrophin- 3 can be used in neurosurgery for the treatment of patients with spinal cord injuries.

Enriched cultures of olfactory ensheathing cells and neural stem/progenitor cells were obtained according to our developed protocols from the olfactory mucosa of rat and human. It has been shown that only transplantation of human and rat olfactory ensheathing cells leads to a significant decrease in the size of cysts, as well as their complete disappearance in some animals.

The experimental post-traumatic spinal cord cysts were modeled. It has been shown that NT-3 enhances the effectiveness of the use of human olfactory ensheathing cells in the treatment of experimental spinal cord cysts.

In this work, an optimal protocol was developed for obtaining adhesion culture of neural stem/progenitor cells (NSPC) of rat olfactory mucosa. During the development of the protocol, the conditions for cell culturing on adhesion substrates fibronectin and laminin in DMEM/F-12 and neurobasal media with the same culture additives were compared. Cell proliferation was maximum during culturing on both substrates in the neurobasal medium. Using the immunofluorescence method, we found that culturing on fibronectin in the neurobasal medium ensured maximum (52.22%) content of nestin-positive cells in comparison with other culturing conditions. The highest percentage of βIII-tubulin-positive cells was detected in cultures growing on fibronectin in the neurobasal medium and in DMEM/F-12 (79.11 and 83.52%, respectively). Culturing in adhesion cultures in the neurobasal medium on fibronectin allowed obtaining cultures enriched with NSPC and neurons differentiating from them in a quantity sufficient for further transplantation. The developed protocol can be recommended for obtaining NPSC from human olfactory mucosa for the treatment of spinal cord injuries.

In experiments on rats, co-transplantation of olfactory ensheathing cells of the human olfactory mucosa and neural stem/progenitor cells from the same source into post-traumatic cysts of the spinal cord led to improvement of the motor activity of the hind limbs and reduced the size of the cysts in some animals by 4-12%. The transplantation of a combination of the olfactory mucosa cells is effective and can be used in preclinical trials for the treatment of spinal cord injuries.