Mesenchymal stromal cells in Rheumathology: Recent findings

Mesenchymal stromal cells (MSCs) have emerged as promising therapeutic candidates for osteoarticular diseases because of their combined immunomodulatory, trophic, and regenerative properties. Although initially studied for their multipotent differentiation capacity, MSCs are now understood to act predominantly through context-dependent paracrine mechanisms, including secretion of soluble mediators and extracellular vesicles, as well as through interactions with innate and adaptive immune cells. These mechanisms enable MSCs to modulate inflammatory responses, suppress T- and B-cell activation, inhibit dendritic cell maturation, and promote anti-inflammatory macrophage polarization, thereby reshaping the joint microenvironment toward resolution and tissue repair.

In rheumatoid arthritis, MSC therapy is supported by strong biological plausibility, with preclinical studies demonstrating reduction of Th1/Th17 responses and enhancement of regulatory T-cell activity. Early clinical trials suggest a favorable safety profile, although evidence for sustained clinical remission remains limited. In focal cartilage defects, MSC-based strategies—particularly when combined with biomaterial scaffolds—have shown potential to enhance cartilage repair and improve functional outcomes. In osteoarthritis and degenerative disc disease, therapeutic effects appear to rely mainly on trophic and immunoregulatory signaling rather than durable cellular engraftment.

Despite encouraging progress, major translational challenges remain, including variability in cell sources, manufacturing protocols, dosing strategies, and patient selection. Future advances will likely depend on standardized cell products, robust potency assays, precision-medicine trial design, and emerging cell-free approaches such as MSC-derived extracellular vesicles.