Neural mechanisms underlying pain sensitization in painful rotator cuff tear

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K07295
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 51030:Pathophysiologic neuroscience-related
• Research Institution: Kochi University
• Principal Investigator: Izumi Masashi 高知大学, 教育研究部医療学系臨床医学部門, 准教授 (60420569)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: 腱板断裂 / 痛み

Outline of Final Research Achievements

We conducted a translational research to find a contribution of altered neural mechanisms associated with pain (pain sensitization) in patients with rotator cuff tear (RCT). Our rat models of RCT demonstrated that large tear is strongly associated with heightened pain severity, but even a small tear can aggravate pain when the torn tendon is degenerated. CGRP upregulation driven by peripheral NGF possibly played a pivotal role in the genesis and exacerbation of pain in small RCT. In addition, our clinical trial revealed that widespread hyperalgesia was only associated with rest pain, but not with shoulder motion pain and nocturnal pain. These findings suggest that further multifactorial assessments including psychological factors are warranted when evaluating patients with RCT.

Free Research Field

整形外科学、疼痛学

Academic Significance and Societal Importance of the Research Achievements

腱板断裂は肩の痛みを来たす代表的疾患であるが、診察や画像検査による肩の局所所見だけでは説明できない難治性の痛みを有する患者が存在する。本研究によって、腱板断裂患者の痛みに神経系の機能変化による修飾がある可能性が示された。多面的、包括的な評価を行うことで、「必要な患者に神経系をターゲットにした治療を積極的に追加する」といった、痛みのメカニズムに応じたテーラーメイドな治療を実践できるようになると考えている。