Sulfated Alginate Hydrogels Prolong the Therapeutic Potential of MSC Spheroids by Sequestering the Secretome. Issue 21 (5th September 2021) - Gionet‐Gonzales, Marissa
Abstract: Cell‐based approaches to tissue repair suffer from rapid cell death upon implantation, limiting the window for therapeutic intervention. Despite robust lineage‐specific differentiation potential in vitro, the function of transplanted mesenchymal stromal cells (MSCs) in vivo is largely attributed to their potent secretome comprising a variety of growth factors (GFs). Furthermore, GF secretion is markedly increased when MSCs are formed into spheroids. Native GFs are sequestered within the extracellular matrix (ECM) via sulfated glycosaminoglycans, increasing the potency of GF signaling compared to their unbound form. To address the critical need to prolong the efficacy of transplanted cells, alginate hydrogels are modified with sulfate groups to sequester endogenous heparin‐binding GFs secreted by MSC spheroids. The influence of crosslinking method and alginate modification is assessed on mechanical properties, degradation rate, and degree of sulfate modification. Sulfated alginate hydrogels sequester a mixture of MSC‐secreted endogenous biomolecules, thereby prolonging the therapeutic effect of MSC spheroids for tissue regeneration. GFs are sequestered for longer durations within sulfated hydrogels and retain their bioactivity to regulate endothelial cell tubulogenesis and myoblast infiltration. This platform has the potential to prolong the therapeutic benefit of the MSC secretome and serve as a valuable tool for investigating GF sequestration. Abstract : Spheroids of mesenchymal stromal cells (MSCs) secrete high levels of relevant growth factors (GFs) for tissue regeneration. Sulfated alginate can sequester these GFs through ionic interactions, allowing increased therapeutic potency to invading cells. This paper investigates how MSC spheroid‐secreted GFs are retained in sulfated alginate and their ability to influence cell function in vitro.