Development of a novel insulin resistance index that is minimally affected by hepatic insulin clearance

2018 Fiscal Year Final Research Report

• Project/Area Number: 16K08935
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Laboratory medicine
• Research Institution: Tottori University
• Principal Investigator: OKURA Tsuyoshi 鳥取大学, 医学部, 講師 (80510073)
• Research Collaborator: FUJIOKA Yohei ; NAKAMURA Risa
• Project Period (FY): 2016-04-01 – 2019-03-31
• Keywords: インスリン抵抗性 / 2型糖尿病

Outline of Final Research Achievements

Increased hepatic insulin clearance (HIC) is important in the pathophysiology of type 2 diabetes mellitus (T2DM). The aim of this study is to analyze an effective insulin resistance (IR) index that is minimally affected by HIC. Our study involved 20 participants with T2DM and 21 healthy participants without diabetes (Non-DM). Participants underwent a meal tolerance test from which HOMA-IR and HIC were calculated. Participants then underwent a glucose clamp from which the glucose disposal rate (GDR) was measured. The index CPR-IR = 20/(fasting CPR × fasting plasma glucose) was correlated more strongly with GDR, than was HOMA-IR, and CPR-IR could be used to estimate GDR. In T2DM participants with HIC below the median, HOMA-IR and CPR-IR were equally well correlated with GDR. In T2DM with high HIC, CPR-IR correlated with GDR while HOMA-IR did not. CPR-IR could be a simple and effective index of insulin resistance for patients with type 2 diabetes that is minimally affected by HIC.

Free Research Field

糖尿病

Academic Significance and Societal Importance of the Research Achievements

インスリン抵抗性の評価方法はグルコースクランプ法が最も精密であるが、2時間以上かかる検査であり、簡便にインスリン抵抗性を評価する方法が必要である。これまで血中インスリン値を用いたHOMA-IRが頻用されてきたが、その信頼性に疑問が生じる症例がある事が問題であった。本研究ではその原因が肝臓におけるインスリンの分解によるものであり、この影響を受けない我々が開発した血中Cペプチドを用いたCPR-IRが有効であることを報告した。本研究により、糖尿病診療や臨床研究に有効な指標が確認され、学術的、社会的にも貢献したと考えられる。