The Human Omental Adipose Depot Mitigates Inflammation, Immune Response, and Oxidative Stress Pathways in Response to Injury via Its Secretome.

Human intraperitoneal omental adipose tissue, part of the visceral adipose depots, surrounds the abdominal organs and has functions distinct from the subcutaneous adipose depots. In the clinical setting, it is observed that the omentum is beneficial to combat internal sources of inflammation, oxidative stress, and injury-related stress. However, the molecular mechanisms involved in these functions are not fully understood. We previously demonstrated that adipose stem cells derived from human omental adipose tissue (om-hASCs) secrete exosomes (exos). We and others have extensively evaluated the subcutaneous adipose depot-derived exosomes; however, the role of adipose stem cells derived from the human omental depot (om-hASCs) remains less known. In this study, we postulated that exosomes from om-hASCs (om-hASCexos) drive the repair ability of the omentum to heal organs after internal injury and insults. First, we characterized the om-hASCexos using a proteomic analysis which identified the distinct cargo. Using in vitro injury models, we show that om-hASCexos significantly improve cell migration and proliferation, while decreasing oxidative stress and inflammation. To study acute in vivo healing, a rat wound model was evaluated. Om-hASCexos significantly improved the healing rate of injuries. RNAseq revealed that om-hASCexo treatment acts upon pathways associated with lipid and fatty acid metabolism, apoptosis, immune response, and cell differentiation. The pathway analysis indicated that om-hASCexos significantly regulate the expression of Clec5a and Trem1 in the immune response pathway. Overall, we demonstrate the singular properties of om-hASCexos that are distinct from other sources of hASC. Thus, this study provides an understanding of the unique ability of the omental adipose depot to combat internal injuries.