Introduction: Sepsis is a life-threatening inflammatory condition of multiple organ dysfunction that has no specific drug for its treatment because of having multiple pathways of the immune system, making them highly evasive. In this study, mesenchymal stem cells (MSCs) were engineered as hybrid spheroids (HS) made up of MSCs and Metformin-loaded microspheres (Met-MS) to enhance their antioxidant, anti-inflammatory, and immunomodulatory properties for sepsis treatment.

Methods: Met-MS was fabricated using the double emulsion method (W/O/W) and characterized for physiochemical properties, including analysis of loading capacity, in vitro kinetic release test, drug encapsulation, and their toxicity. Afterward, adipose tissue-derived mesenchymal stem cells, either with or without Met-MS were incubated for 6 h in an AggreWell™ microwell culture plate to prepare spheroids (Sph) or hybrid spheroids (HS), respectively. HS was further analyzed for antioxidant and immunomodulatory activities. The in vivo efficacy of sHS was evaluated in sepsis-induced liver injury after post-hepatic portal vein transplantation.

Results: Met-MS exhibited an average size of 3.4 ± 1.3 µm and in vitro release up to 25 days, which was fabricated with MSCs using AggreWell™ methods. The non-toxic dose of Met-MS10 was used for HS. Notably, immunomodulatory and anti-inflammatory markers were robustly enhanced in cell-particle hybrid systems. In addition, HS significantly suppressed the expression of inflammatory markers such as IL-6, TNF-α, and IL-1β. Subsequently, disease index, AST, ALT, MPO assay, and histological analysis of the HS-transplanted group showed the recovery from LPS-induced sepsis, including an increased survival rate compared to other groups.

Conclusion: In summary, HS holds a promising therapeutic alternative for the treatment of sepsis as well as other inflammatory diseases by integrating immune modulation, anti-inflammatory, and regenerative medicine.