Are lower circulating levels of irisin secreted by skeletal muscle associated with higher risks of deterioration of insulin resistance and fracture? A 10-year follow-up study

2023 Fiscal Year Final Research Report

• Project/Area Number: 22K19740
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 59:Sports sciences, physical education, health sciences, and related fields
• Research Institution: Osaka Medical and Pharmaceutical University
• Principal Investigator: Tamaki Junko 大阪医科薬科大学, 医学部, 教授 (90326356)
• Co-Investigator(Kenkyū-buntansha): 伊木 雅之 近畿大学, 医学部, 教授 (50184388) ; 立木 隆広 高知県立大学, 看護学部, 准教授 (10734650) ; 千葉 康敬 近畿大学, 大学病院, 准教授 (80362474)
• Project Period (FY): 2022-06-30 – 2024-03-31
• Keywords: アイリシン / インスリン抵抗性 / 骨折 / コホート研究 / 筋産生因子

Outline of Final Research Achievements

Irisin secreted by the skeletal muscles contributes to glucose homeostasis. Therefore, we prospectively investigated the relationship between serum irisin levels and insulin resistance. Deterioration of insulin resistance at follow-up was related to higher serum irisin levels, independent of age, body mass index, and HDL cholesterol levels at baseline during the 11-year follow-up period.
The deterioration of insulin resistance seems to trigger diabetes mellitus in the Japanese population compared with that in Western individuals. The prevalence of glucose intolerance in Japanese women increases with age, with approximately 10% in women in their 60s and 20% in those in their 70s. Our findings indicate that serum irisin levels increase before the deterioration of insulin resistance. Thus, irisin may be a beneficial predictive marker for detecting high-risk populations with pathological conditions and diseases related to reduced healthy life expectancy.

Free Research Field

疫学、公衆衛生学

Academic Significance and Societal Importance of the Research Achievements

インスリン抵抗性が増悪すると、筋肉や脂肪組織の糖取り込み能及び肝臓による糖新生の抑制が低下し、糖尿病を引き起こしやすいとされる。日本人は欧米人に比べ僅かなインスリン抵抗性の増加が糖尿病発生の引き金となりやすいことも指摘されている。我が国では、加齢に伴い耐糖能異常の割合は増加し、糖尿病が強く疑われる者が、女性の60歳代で1割、70歳以上では約2割に上る。本課題で、アイリシンの血中濃度は糖代謝増悪に先立ち高くなることの関連が明らかとなり、アイリシンは糖代謝異常が関連する健康寿命延伸を阻む様々な病態・疾患のハイリスク者の発見に有用である可能性が示されたと考える。