Omental adipose MSC protects endothelial functions and induces tissue regeneration against S. aureus infection
Surgical site infection (SSI) increases the risks of morbidity and mortality rates among patients. While antibiotics are the conventional treatment for infections, their indiscriminate use leads to an increase in bacterial resistance, limiting their effectiveness. Previous clinical studies have demonstrated the efficacy of omentum grafts, a type of adipose tissues, in cardiothoracic surgery for inhibiting SSI development. Omental adipose tissues contain several types of cells, including mesenchymal stem cells (MSC), a type of cells which is reported to possess the abilities of tissue protection and infection control. However, most of the research used MSC derived from subcutaneous adipose tissues; meanwhile, the antibacterial properties of omental adipose tissue-derived MSC (oAT-MSC) have not been clarified. In this study, we found that conditioned media (CM) derived from oAT-MSC possess the ability to impair the growth of S. aureus and MRSA strain, as similar as those derived from MSC of subcutaneous adipose tissue. In addition, CM derived from oAT-MSC protected endothelial cells, preserving their morphology, functionality and reduced intracellular ROS following bacterial exposure. Furthermore, in a mouse infection model with S. aureus, CM derived from oAT-MSC supported the mice survival and facilitated wound healing post infection by promoting re-epithelialization and supporting tissue repair process. Transcriptomic profile (RNAseq)analysis of oAT-MSC revealed the presence of secreted agents that are involved in promoting cellular and tissue protection. These results suggested the role of oAT-MSC in the efficacy of omentum grafts in cardiothoracic surgery for preventing SSI development. With the abilities to prevent infections and preserve endothelial function under pathological conditions, adipose tissue-MSC-derived factors could potentially be an effective cell-free tool for infection control and for the improvement of clinical outcomes in surgeries.