GPX4 Expression After Kono-S vs Conventional Anastomosis

Overview

Crohn's disease is a long-term condition that causes inflammation in the bowel. Many people with Crohn's will need surgery at some point to remove damaged sections of intestine. Although surgery can improve symptoms, the disease often comes back near the join (anastomosis) where the bowel has been reconnected. Surgeons use different techniques to reconnect the bowel. One newer approach, called the Kono-S anastomosis, is designed to reduce the risk of Crohn's disease returning. Early results are promising, but it is still not fully understood why it may work better than traditional methods. This project aims to explore how the bowel heals after surgery by looking at oxidative stress, a type of tissue damage caused by an imbalance of harmful molecules in the body. The investigators will focus on a protective protein called glutathione peroxidase-4 (GPX4), an anti-oxidative enzyme that reduces oxidized phospholipids in biomembranes. By analysing tissue samples taken before and after surgery, the investigators will compare patients who had the Kono-S technique with those who had standard surgical joins. The investigators want to see whether differences in healing at a microscopic level could explain why some patients do better than others. The findings from this study could: * Improve understanding of why Crohn's disease comes back after surgery. * Help surgeons choose the best technique for each patient. * Support the development of new treatments aimed at improving healing. Ultimately, this research aims to reduce the risk of disease recurrence and improve long-term outcomes for people living with Crohn's disease.

Postoperative recurrence of Crohn's disease frequently occurs at or near the ileocolic anastomosis.1 Increasing evidence suggests that oxidative stress plays a central role in anastomotic healing, fibrosis and mucosal recurrence. Surgical injury triggers neutrophil recruitment and reactive oxygen species (ROS) production, which can initiate lipid peroxidation within intestinal epithelial membranes.3 Lipid peroxidation products such as malondialdehyde (MDA) and 4-hydroxynonenal (4-HNE) activate inflammatory and fibrotic signalling pathways including mitogen-activated protein kinase (MAPK), nuclear factor-κB (NF-κB) and transforming growth factor- β (TGF-β).2,4 GPX4 is a key antioxidant enzyme that detoxifies lipid peroxides and prevents ferroptosis, a regulated form of oxidative cell death.5 Reduced GPX4 activity has been described in inflammatory bowel disease and may contribute to epithelial injury and disease progression.5 Recent results have demonstrated that a reduced GPX4 expression at time of surgery predicts disease recurrence after ileocolonic resection independent of established clinical risk factors (e.g., smoking, penetrating disease, sex and age). Despite the recognised importance of oxidative stress in intestinal inflammation, its role at the surgical anastomosis in Crohn's disease has not been directly studied. The Kono-S anastomosis is a functional end-to-end, antimesenteric configuration designed to reduce luminal distortion and faecal stasis while excluding mesenteric inflammatory influence. Early studies suggested reduced endoscopic recurrence compared with conventional anastomoses, although long-term clinical results remain mixed.6 The biological mechanisms underlying any benefit remain poorly understood. The investigators hypothesise that the Kono-S anastomotic configuration may reduce local oxidative stress at the anastomotic site by limiting reactive oxygen species exposure and subsequent lipid peroxidation, as reflected by lower levels of markers such as malondialdehyde (MDA) and 4-hydroxynonenal (4-HNE) compared with conventional techniques. This more favourable redox environment may support preservation of epithelial antioxidant defence mechanisms, including maintenance of glutathione peroxidase-4 (GPX4) expression and activity, thereby reducing susceptibility of intestinal epithelial cells to ferroptosis. In turn, reduced lipid peroxidation may attenuate activation of key pro-inflammatory and pro-fibrotic signalling pathways, including MAPK, NF-κB and TGF-β, with potential downstream effects on mucosal inflammation and fibrotic remodelling.4 Overall, these mechanisms may contribute to improved anastomotic healing and a lower risk of early endoscopic recurrence.