Effects of a deviated food habit on immune response of adipose tissues to bacterial infections, and their association with intestinal microflora

2019 Fiscal Year Final Research Report

• Project/Area Number: 17K01850
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Applied health science
• Research Institution: The University of Tokushima
• Principal Investigator: ARIMOCHI Hideki 徳島大学, 大学院医歯薬学研究部(医学域), 助教 (30311822)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Keywords: 皮下膿瘍 / 腹腔内感染 / 抗菌ペプチド / 脂肪組織

Outline of Final Research Achievements

To clarify effects of a deviated food habit on adipose infection immunity, high fat diet (HFD) fed mice were infected with several kinds of bacteria at subcutaneous or abdominal cavity, then bacterial number was estimated. When Staphylococcus aureus was infected subcutaneously, bacterial number was low in HFD group compared with normal diet (ND) group. However, bacterial numbers in HFD group were high in other models. Expression of adipose bactericidal peptide didn't correlate with the bacterial number in some models. When LMP7 deficient mouse with immatured adipocyte was infected under ND condition, bacterial number and adipose bactericidal peptide expression were high and low, respectively, compared with wild type (WT) mouse, although more bacteria and peptide expression than WT were observed in HFD condition. These results suggest bacterial clearance in obese was decline in most cases, and the adipose bactericidal peptide might be a minor factor to prevent bacterial infections.

Free Research Field

細菌学

Academic Significance and Societal Importance of the Research Achievements

食生活の偏りは肥満の原因の一つであるが、肥満になると免疫系の質的変化が起こり、感染症を起こしやすくなると推測される一方、肥満の人の方が脂肪細胞由来の抗菌ペプチドの血中濃度が高いという報告もあり、肥満が細菌感染に及ぼす影響については議論されているところである。今回の研究成果から、肥満は一部の細菌による感染では菌の排除を促進するが、ほとんどの場合は抑制的に働くことが分かり、また脂肪細胞由来の抗菌ペプチドは感染制御にあまり寄与しなかったことから、肥満は細菌感染に悪影響を及ぼすということが示唆された。今回の成果は肥満が細菌感染に及ぼす影響の一端を明らかにしたという点で、意義があるものと考える。