Hidetoshi Eguchi

Inflammatory bowel disease (IBD) is one of the intractable diseases. Nutritional components associated with IBD have been identified, and it is known that excessive methionine intake exacerbates inflammation, and that tryptophan metabolism is involved in inflammation. Analysis of the gut microbiota has also progressed, where Lactobacillus regulate immune cells in the intestine and suppress inflammation. However, whether the methionine and tryptophan metabolic pathways affect the growth of intestinal Lactobacillus is unknown. Here we show how transient methionine, tryptophan, and niacin deficiency affects the host and gut microbiota in mouse models of colitis (induced by dextran sodium sulfate) fed a methionine‐deficient diet (1K), tryptophan and niacin‐deficient diet (2K), or methionine, tryptophan, and niacin‐deficient diet (3K). These diets induced body weight decrease and 16S rRNA analysis of mouse feces revealed the alterations in the gut microbiota, leading to a dramatic increase in the proportion of Lactobacillus in mice. Intestinal RNA sequencing data confirmed that the expression of several serine proteases and fat‐metabolizing enzymes were elevated in mice fed with methionine, tryptophan, and niacin (MTN) deficient diet. In addition, one‐carbon metabolism and peroxisome proliferator‐activated receptor (PPAR) pathway activation were also induced with MTN deficiency. Furthermore, changes in the expression of various immune‐related cytokines were observed. These results indicate that methionine, tryptophan, and niacin metabolisms are important for the composition of intestinal bacteria and host immunity. Taken together, MTN deficiencies may serve as a Great Reset of gut microbiota and host gene expression to return to good health.

Purpose Postoperative venous thromboembolism (VTE) risk is pronounced after abdominal cancer surgery. Enoxaparin shows promise in preventing VTE in gastrointestinal, gynecological, and urological cancers, but its application after surgery for hepatobiliary‐pancreatic malignancy has been under‐evaluated due to bleeding concerns. We confirmed the safety of enoxaparin administration in patients undergoing curative hepatobiliary‐pancreatic surgery for malignancies in a prospective, multi‐center, phase I study. Methods The study was conducted from April 2015 to May 2021 across eight specialized centers. Patients ( n = 262) were randomized to enoxaparin prophylaxis given postoperatively for 8 days ( n = 131) or control ( n = 131). The primary endpoint was the efficacy in reducing VTE. Secondary endpoints examined safety. Results The full analysis set included 259 patients (131 control, 129 enoxaparin). The per‐protocol population included 233 patients (117 control, 116 enoxaparin). Most cases were hepatic malignancies (111 control, 111 enoxaparin). The median administration duration of enoxaparin was 7 days, with 92% receiving 4000 units/day. Despite a reduction in the relative risk (RR) of VTE due to postoperative enoxaparin administration, the results were not significant (control: four cases, 3.4% vs. treatment: two cases, 1.7%; RR 0.50, 95% CI 0.09–2.70; p = 0.6834). No significant difference was found in the incidence of bleeding events (control: five cases, 4.3% vs. treatment: five cases, 4.3%, RR 1.00, 95% CI 0.53–1.89; p = 1.0000). Conclusions The perioperative administration of enoxaparin in hepatobiliary‐pancreatic malignancies is feasible and safe. However, further case accumulation and investigation are necessary to assess its potential in reducing the occurrence of VTE.