Mesenchymal stem cells (MSCs) are a type of multipotent, non-hematopoietic cells of mesodermal origin. Due to their strong immunomodulatory, immunosuppressive, and regenerative potential, MSCs are used in cell therapy for inflammatory, immune-mediated, and degenerative diseases. Exosomes derived from MSCs have several advantages over MSC therapy, including non-immunogenicity, lack of infusion toxicity, ease of isolation, manipulation, and storage, cargo specificity, and the absence of tumor-forming potential and ethical concerns. We hypothesized that preconditioning human umbilical cord blood mesenchymal stem cells (hUCB-MSCs) with the proinflammatory cytokines interleukin 17 (IL-17), IL-22, and tumor necrosis factor alpha (TNF-α), the increased levels of which are typical in psoriasis patients, can significantly increase the therapeutic efficacy of both hUCB-MSCs and their exosomes (hUCB-MSC-Exo). Our aim was to compare the therapeutic effects of hUCB-MSCs preconditioned with various combinations of proinflammatory cytokines and their hUCB-MSC-Exo, in an in vivo imiquimod-induced psoriasis-like skin inflammation model in mice. Our results showed a significant attenuation of psoriasis symptoms (erythema, scaling, and skin thickness) in mice treated with intact hUCB-MSCs, hUCB-MSCs preconditioned with IL-22 and TNF-α, and hUCB-MSC-Exo preconditioned with IL-17, IL-22 and TNF-α (MSC-Exo 3C). However, the most pronounced therapeutic effect was observed with MSC-Exo 3C treatment. In summary, we demonstrated that MSC-Exo 3C transplantation has therapeutic potential for treating psoriasis-like skin lesions.

Diabetic retinopathy (DR) is the leading cause of vision loss in early adulthood, caused by disruption of the retinal microvasculature. In the early stages of DR, there is a loss of pericytes, the cells responsible for maintaining vascular stability. Pericytes are progenitor cells and possess stem cell properties such as the potential to differentiate into various cell types, surface markers similar to mesenchymal stem cells (MSCs), and the ability to modulate the immune response. Human adipose-derived MSCs, when cultured with certain growth factors, acquire a pericyte-like phenotype, which expands the potential for pericyte applications in therapy. Current treatments for DR include anti-vascular endothelial growth factor agents, corticosteroids, and laser photocoagulation. All of these treatments are symptomatic and have adverse effects. This review covers the prevalence of DR in Kazakhstan and worldwide, the pathogenesis of the disease at the molecular and clinical level, treatment methods and modern approaches based on stem cells and pericytes.