Multiple immune and tissue cell populations via secreted paracrine factors

The phrase "Multiple immune and tissue cell populations via secreted paracrine factors" refers to a systemic therapeutic mechanism rather than a discrete molecular target or receptor [1]. This terminology is predominantly used in the field of regenerative medicine, specifically by companies like Mesoblast, to describe the pleiotropic effects of mesenchymal stem cells (MSCs) [2]. Instead of a traditional drug-receptor interaction, the therapy relies on the release of a diverse cocktail of "paracrine factors"—including cytokines, chemokines, and extracellular vesicles—that act on various cell types throughout the body [1][3]. These factors work in concert to modulate the activity of T-cells, B-cells, dendritic cells, and macrophages, effectively dampening pathological inflammation and stimulating endogenous tissue repair [3]. This approach is particularly relevant for treating complex, multi-organ inflammatory conditions such as steroid-refractory graft-versus-host disease (SR-aGvHD) and acute respiratory distress syndrome (ARDS) [2]. Because the "target" is a network of cellular interactions rather than a single protein, it represents a shift toward holistic biological modulation in drug development [1]. [1] Galipeau J, Sensébé L. Mesenchymal Stromal Cells: Clinical Challenges and Therapeutic Opportunities. Cell Stem Cell. 2018;22(6):824-833. [2] Mesoblast Limited. FDA Briefing Document: Remestemcel-L. 2020. [3] Caplan AI, Correa D. The MSC: an injury drugstore. Cell Stem Cell. 2011;9(1):11-15.

Other names

MSC-mediated paracrine signalingMesenchymal stromal cell secretomePleiotropic immunomodulationCell-mediated paracrine effect

The mechanism involves the therapeutic administration of cells (typically mesenchymal stem cells) that sense inflammatory signals and respond by secreting a broad array of bioactive molecules, such as TGF-beta, PGE2, and IL-10, which simultaneously modulate multiple immune cell subsets and promote tissue regeneration [1][2][3].