A novel strategy for preventing postoperative delirium using indigestible oligosaccharides

2023 Fiscal Year Final Research Report

• Project/Area Number: 20K17841
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 55050:Anesthesiology-related
• Research Institution: Sapporo Medical University
• Principal Investigator: Nishihara Noriaki 札幌医科大学, 医学部, 研究員 (70836436)
• Project Period (FY): 2020-04-01 – 2024-03-31
• Keywords: 術後せん妄 / 腸内細菌叢 / 難消化性オリゴ糖 / セロトニン

Outline of Final Research Achievements

Postoperative delirium is recognized to be mainly caused by inflammation in the brain due to surgical invasion (neuroinflammation), and control of neuroinflammation is thought to contribute to prevention of postoperative delirium. We have attempted to control neuroinflammation by administering a non-digestible oligosaccharide (raffinose) to the intestinal microbiota and to improve and prevent postoperative delirium by administering raffinose. The results showed that in aged mice, there was no difference in inflammatory cytokines in the brain, but in the raffinose-treated group, there was a decrease in blood stress hormone, an increase in serotonin, an increase in diversity of the intestinal microflora, and an improvement in delirium-like behavior. The results suggest that serotonin-mediated mechanisms, which are different from the regulation of neuroinflammation, may ameliorate postoperative delirium.

Free Research Field

麻酔科

Academic Significance and Societal Importance of the Research Achievements

これまで難消化性オリゴ糖による腸内細菌叢へのアプローチにより、術後せん妄を改善できたという報告はあったものの、私たちが日常的に入手でき、摂取可能なラフィノースを用いた研究は存在しなかった。今回、そのラフィノースの投与により術後せん妄を行動学的に改善できる可能性が示唆されたことは新規性が高いだけではなく、現実的な術後せん妄予防策の提示に繋がると考えている。また、術後せん妄は神経炎症単一の機序ではなく、腸内細菌叢を介したセロトニン経路によっても制御される可能性が示唆されたことは興味深い結果となった。