Localized Delivery of Mesenchymal Stem Cell Spheroids via an Injectable Hydrogel for Rheumatoid Arthritis Therapy.

Area of Science:

• Biomaterials Science
• Immunology
• Regenerative Medicine

Background:

• Rheumatoid arthritis (RA) involves chronic joint inflammation and tissue damage.
• Current RA therapies primarily reduce inflammation but lack regenerative capabilities and cause side effects.
• There is a need for localized treatments that combine immunomodulation and tissue regeneration for RA.

Purpose of the Study:

• To develop an injectable hydrogel system for intra-articular delivery of umbilical mesenchymal stem cell (UMSC) spheroids for RA treatment.
• To evaluate the immunomodulatory and regenerative potential of the hydrogel-spheroid system in vitro and in vivo.

Main Methods:

• Development of a collagen-hyaluronic acid (Col-HA-NHS) hydrogel with shear-thinning and self-healing properties.
• Encapsulation of UMSC spheroids within the hydrogel for enhanced paracrine factor secretion.
• In vitro assessment of macrophage polarization (M1) and reactive oxygen species (ROS) levels.
• Evaluation of the hydrogel-spheroid system in a rat collagen-induced arthritis (CIA) model, assessing paw swelling, clinical scores, and histopathology.

Main Results:

• The Col-HA-NHS hydrogel exhibited favorable biocompatibility, controlled degradation, and injectable properties.
• Encapsulated UMSC spheroids (S-UMSCs) showed enhanced secretion of growth factors (EGF, FGF) compared to monolayer cultures.
• The in vitro hydrogel-spheroid system (CH/S-UMSCs) reduced M1 macrophage polarization and ROS levels.
• Intra-articular CH/S-UMSCs administration in the CIA model significantly reduced paw swelling, improved clinical scores, and alleviated joint damage (synovial inflammation, cartilage erosion, bone destruction).
• Treatment improved bone mineral density (BMD) and trabecular microstructure.

Conclusions:

• The injectable Col-HA-NHS hydrogel effectively delivers UMSC spheroids for localized RA treatment.
• This combinatory strategy integrates immunomodulation and tissue regeneration, demonstrating synergistic therapeutic effects.
• The developed hydrogel-spheroid system shows significant promise as a localized and regenerative therapy for rheumatoid arthritis.