Protective effect of adipose tissue-derived mesenchymal stromal cells in an experimental model of high-risk colonic anastomosis

Background: Dehiscence of intestinal anastomosis results in high morbidity and mortality. The aim of this study was to investigate the effects of locally administered adipose tissue-derived mesenchymal stromal cells in a model of high-risk colonic anastomosis in rats.

Methods: Seven days after induction of colitis with 2,4,6-trinitrobenzene sulfonic acid, Wistar rats were submitted to a transection of the descending colon followed by end-to-end anastomosis and were then treated with 2×10⁶ adipose tissue-derived mesenchymal stromal cells (from the preperitoneal fat) or an acellular culture solution instilled onto the surface of the anastomosis. At day 14, after macroscopic survey of the abdominal cavity, the anastomotic area was submitted to histologic and immunohistochemical analysis, evaluation of myeloperoxidase activity, fibrosis, epithelial integrity, NF-κ B activation, expression of inflammatory cytokines, and extracellular matrix-related genes.

Results: Anastomotic leakage and mortality associated with high-risk anastomosis decreased with treatment with adipose tissue-derived mesenchymal stromal cells (P < .03). Application of adipose tissue-derived mesenchymal stromal cells resulted in lower histologic scores (P = .011), decreased deposition of collagen fibers (P = .003), preservation of goblet cells (P = .033), decreased myeloperoxidase activity (P = .012), decreased accumulation of CD4+ T-cells (P = .014) and macrophages (P = .011) in the lamina propria, a decrease in the number of apoptotic cells (P = .008), and the activation of NF-κ B (P = .036). Overexpression of IL-17, TNF-α , IFN-γ, and metalloproteinases in the acellular culture solution-treated, high-risk anastomosis group decreased (P < .05) to near normal values with adipose tissue-derived mesenchymal stromal cells treatment.

Conclusion: Improvements in outcomes of a high-risk colonic anastomosis with adipose tissue-derived mesenchymal stromal cells therapy reflect the immunomodulatory activity and healing effect of these cells, even after just topical administration and reinforces their use in future translational research.