RA sarcopenia therapy targeting the lower leg slow-twitch muscle molecular chaperone-myokine induction therapy

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K19914
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 59010:Rehabilitation science-related
• Research Institution: Kyoto Prefectural University of Medicine
• Principal Investigator: Toyama Shogo 京都府立医科大学, 医学(系)研究科(研究院), 客員講師 (00388183)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: 関節リウマチ / サルコペニア / 遅筋 / 運動

Outline of Final Research Achievements

Using an animal arthritis model, we analyzed the effects of arthritis on fast-twitch and slow-twitch muscles. Muscle atrophy and fibrosis occurred in the soleus muscle, which is rich in slow-twitch muscle fibers, compared to the extensor digitorum longus muscle, which is rich in fast-twitch muscle fibers. Next, the effects of treadmill running were examined. Eif4e, an anabolic marker of muscle protein, was increased in the soleus muscle at 2 weeks after immunosensitization, and atrogin-1, a catabolic marker, was increased at 6 weeks after immunosensitization, depending on the presence or absence of exercise and the muscle. Four weeks of exercise also prevented muscle atrophy in slow-twitch muscles. We hypothesized that treadmill running may prevent atrophy and fibrosis of slow-twitch muscles by modulating the metabolic cycle of the muscles.

Free Research Field

リハビリテーション科学

Academic Significance and Societal Importance of the Research Achievements

関節リウマチ(rheumatoid arthritis; RA)に対する薬物治療の進歩により関節炎の寛解が得られるようになったが、依然としてサルコペニアの罹患率が高くRA患者のADL障害の大きな要因となっている。一方、遅筋は速筋の約5倍マイオカインを分泌することがこれまで明らかになっており、遅筋の比率が高い下腿への刺激
が全身の筋肥大をもたらすことができれば、サルコペニアの有効な治療法になり得ると考えた。