Therapeutic effect of mesenchymal stem cells and their derived exosomes in diseases.

Mesenchymal stem cells (MSCs) are multipotent stem cells characterized by their robust proliferative capacity, homing ability, differentiation potential, and low immunogenicity in vitro. MSCs can be isolated from a variety of tissues, primarily including but not limited to bone marrow, adipose tissue, umbilical cord, placenta, and dental pulp. Although there have been a large number of clinical studies on the treatment of diseases by MSCs and MSCs-derived exosomes (MSCs-EXO), the large-scale clinical application of MSCs and MSCs-EXO have been limited due to the heterogeneity of the results among various studies. This review provides a detailed description of the classification and characterization of MSCs and MSCs-EXO, as well as their extraction methods. Furthermore, this review elaborates on three key mechanisms of MSCs and MSCs-EXO: paracrine mechanisms, immunomodulatory and anti-inflammatory effects, as well as their promotion of tissue regeneration. This review also examines the role of MSCs and MSCs-EXO in cardiovascular diseases, neurological disorders, autoimmune diseases, musculoskeletal disorders, and other systemic diseases over the past five years, while discussing the challenges and difficulties associated with their clinical application. Finally, we systematically summarized and analyzed the potential causes of the various heterogeneous results currently observed. Additionally, we provided an in-depth discussion on the challenges and opportunities associated with the clinical translation of disease treatment approaches based on MSCs, MSCs-EXO, and engineered exosomes.