MSCs and Their Exosomes Show Broad Therapeutic Promise Across Major Disease Categories

Mesenchymal stem cells have evolved from a laboratory curiosity first described in 1868 into one of the most actively investigated therapeutic platforms in modern medicine. This comprehensive 2025 review from Binzhou Medical University Hospital synthesizes the current state of MSC and MSC-derived exosome (MSC-EXO) research, covering classification, isolation methods, mechanisms of action, and clinical applications across five major disease categories over the past five years. The authors identify three foundational therapeutic mechanisms: paracrine signaling (release of growth factors and cytokines), immunomodulation and anti-inflammatory effects, and direct promotion of tissue regeneration.

MSCs can be isolated from at least five primary tissue sources, each with distinct advantages. Bone marrow-derived MSCs (BM-MSCs) were the first characterized and remain widely used, but extraction is invasive and cell quality declines with donor age — aging donors show elevated ROS, increased p21 and p53 expression, and reduced therapeutic adaptability. Adipose-derived MSCs (AD-MSCs) offer higher yields per extraction, more stable morphology, lower senescence rates, and a less burdensome donation process. Umbilical cord MSCs from Wharton's jelly proliferate fastest, express minimal MHC II antigens, and exhibit lower immunogenicity than adult MSCs, making them particularly attractive for allogeneic applications. Placenta-derived and dental pulp-derived MSCs round out the landscape, with dental pulp MSCs uniquely originating from neural crest ectoderm and displaying neurotrophic characteristics relevant to neurological applications.

Exosomes — lipid bilayer vesicles of 50–150 nm secreted by MSCs — have emerged as a compelling cell-free alternative to direct MSC transplantation. MSC-EXOs carry bioactive cargo including proteins, lipids, mRNAs, and microRNAs that recapitulate many of the therapeutic effects of parent cells while avoiding risks of direct cell engraftment such as immune rejection or ectopic differentiation. The review details isolation methods including ultracentrifugation, density gradient separation, and size exclusion chromatography, noting that method choice significantly affects exosome purity, yield, and downstream biological activity.

Clinical and preclinical evidence reviewed spans cardiovascular diseases (myocardial infarction, heart failure), neurological disorders (stroke, spinal cord injury, neurodegenerative diseases), autoimmune diseases (rheumatoid arthritis, lupus, multiple sclerosis), and musculoskeletal disorders (osteoarthritis, bone fractures, tendon injuries). In cardiovascular contexts, MSC-EXOs have demonstrated cardioprotective effects by reducing infarct size and promoting angiogenesis. In neurological applications, dental pulp MSCs' neurotrophic properties show particular promise. Across autoimmune diseases, MSCs suppress pro-inflammatory cytokines and expand regulatory T-cell populations.

Despite this breadth of evidence, the authors identify substantial barriers to clinical translation. Heterogeneity in results across studies stems from variability in MSC source tissue, donor demographics, passage number, culture conditions (FBS vs. human platelet lysate vs. serum-free media), and exosome isolation protocols. Safety concerns include potential tumorigenicity, immunogenic reactions from animal-derived culture components, and inconsistent manufacturing standards. The review concludes by highlighting engineered exosomes — surface-modified or cargo-loaded vesicles — as a promising next-generation strategy to improve targeting specificity and therapeutic potency, while calling for standardized protocols and larger randomized controlled trials to resolve current evidence heterogeneity.