# Knockout Genes in Bowel Anastomoses: A Systematic Review of Literature Outcomes

## TL;DR

This paper reviews how gene knockout models help understand intestinal wound healing and suggests gene therapies could improve recovery.

## Contribution

The study systematically reviews gene knockout models in bowel anastomoses to uncover new insights into intestinal healing mechanisms.

## Key findings

- Deficiencies in IL-10, annexin-A1, and TAFI genes increased inflammation at anastomotic sites.
- COX-1 deficiency reduced angiogenesis, while COX-2 deficiency improved leak rates with PGE2 treatment.
- ANXA1 KO mice showed improved recovery with Ac2-26 nanoparticle treatment.

## Abstract

Background: The intestinal wound healing process is a complex event of three overlapping phases: exudative, proliferative, and remodeling. Although some mechanisms have been extensively described, the intestinal healing process is still not fully understood. There are some similarities but also some differences compared to other tissues. The aim of this systematic review was to summarize all studies with knockout (KO) experimental models in bowel anastomoses, underline any recent knowledge, and clarify further the cellular and molecular mechanisms of the intestinal healing process. A systematic review protocol was performed. Materials and methods: Medline, EMBASE, and Scopus were comprehensively searched. Results: a total of eight studies were included. The silenced genes included interleukin-10, the four-and-one-half LIM domain-containing protein 2 (FHL2), cyclooxygenase-2 (COX-2), annexin A1 (ANXA-1), thrombin-activatable fibrinolysis inhibitor (TAFI), and heparin-binding epidermal growth factor (HB-EGF) gene. Surgically, an end-to-end bowel anastomosis was performed in the majority of the studies. Increased inflammatory cell infiltration in the anastomotic site was found in IL-10-, annexin-A1-, and TAFI-deficient mice compared to controls. COX-1 deficiency showed decreased angiogenesis at the anastomotic site. Administration of prostaglandin E2 in COX-2-deficient mice partially improved anastomotic leak rates, while treatment of ANXA1 KO mice with Ac2-26 nanoparticles reduced colitis activity and increased weight recovery following surgery. Conclusions: our findings provide new insights into improving intestinal wound healing by amplifying the aforementioned genes using appropriate gene therapies. Further research is required to clarify further the cellular and micromolecular mechanisms of intestinal healing.