Roux-en-y gastric bypass biliary derivation protects colorectal cancer | The doctor’s daily life

The slightest risk of colorectal cancer. Therefore, metastases after a red-red gastric bypass (Rygb) would be more explained by the derivation of bile acids than by immune changes, weight loss or modification of the microbiome.

Several meta-analyzes have already shown the protective effect of bariatric surgery against colorectal cancer. Similarly, including Roux-en-Y (RYGB) gastric bypass, but the underlying mechanisms are still poorly understood. Nevertheless, A new study carried out on mice. Moreover, organoids and patients, published in Science Translational Medicine, highlights the involvement of bile acids in the proliferation mechanisms of cancer cells.

Gastric bypass slows down the proliferation of metastases – Roux-en-y gastric bypass biliary derivation

Biliary derivation leads to a delay in the introduction of digestive juices with a quantity of bile acids in the decreased circulation for primaries (endogenous). For example, increased for secondary (produced by the microbiota). Moreover, The circulating. Moreover, gastrointestinal concentration roux-en-y gastric bypass biliary derivation of secondary bile acids is multiplied by two, when the rate of primary bile acids is reduced by 50 % in case of surgery.

Researchers have shown that the decrease in primary bile acid levels in serum contributes to the slowdown in the. development of metastases in 41 patients with metastatic colorectal cancer. In their study. people with serological concentrations of higher total and primary bile acids had faster development of liver metastases (Hazard Ratio HR = 3.077 and HR = 3.365 respectively).

The hypothesis was confirmed in vitro when the team exposed human. murine organoids of colorectal tumors to primary bile acids: experimentation has led to the activation of signaling pathways linked to proliferation, renewal of stem cells and metastatic mechanisms.

An independent effect of weight. inflammation and microbiota

Several other mechanisms associated with the RYGB are likely to have anti -tumor functions: dysbiosis, inflammatory response and weight loss. roux-en-y gastric bypass biliary derivation To verify that it is indeed an effect specific to bile acids, the researchers carried out several analyzes.

Compared to mice having lost weight with a diet alone. obese rodents subject to a hyperlipidal diet presented identical tumorogenesis and metastatic evolution. On the side of inflammation. no alteration was observed on the composition and function of the lymphocytes infiltrating the tumor (til) in operated mice and obese mice with hyperlipid diet. The alteration of inflammation therefore does not seem to be significantly involved in the antitumoral effects of the RYGB.

While the post-Bypass composition of the intestinal microbiome changes. the researchers have carried out fecal transplants from mice operated on unpaid obese mice, without this having a positive effect on carcinogenesis. It is therefore the intervention in itself. the derivation of associated bile acids which reduces the risk of colorectal cancer and its proliferation.

Thus. while bile derivation has an roux-en-y gastric bypass biliary derivation anti-metastatic action, this surgery could be a preventive option in obese patients with non-metastatic colorectal cancer. For researchers. it would also be interesting to know if a specific bile acid is protective or if a particular composition of primary bile acids plays a role, which would open the way for approaches without surgery.