Yanagisawa Akihiro, Ueda Mitsuharu, Sueyoshi Takanao, Nakamura Eiichi, Tasaki Masayoshi, Suenaga Genki, Motokawa Hiroaki, Toyoshima Risa, Kinoshita Yumiko, Misumi Yohei, Yamashita Taro, Sakaguchi Mitsuru, Westermark Per, Mizuta Hiroshi, Ando Yukio
a Department of Orthopaedic Surgery , Graduate School of Medical Sciences, Kumamoto University , Chuo-ku, Kumamoto , Japan .
b Department of Neurology , Graduate School of Medical Sciences, Kumamoto University , Chuo-ku, Kumamoto , Japan .
Amyloid. 2016;23(1):26-32. doi: 10.3109/13506129.2015.1115758. Epub 2015 Dec 24.
Amyloidosis is a protein conformational disorder in which amyloid fibrils accumulate in the extracellular space and induce organ dysfunction. Recently, two different amyloidogenic proteins, transthyretin (TTR) and apolipoprotein A-I (Apo A-I), were identified in amyloid deposits in knee joints in patients with knee osteoarthritis (OA). However, clinicopathological differences related to those two kinds of amyloid deposits in the knee joint remain to be clarified. Here, we investigated the clinicopathological features related to these knee amyloid deposits associated with knee OA and the biochemical characteristics of the amyloid deposits. We found that all of our patients with knee OA had amyloid deposits in the knee joints, especially in the meniscus, and those deposits were primarily derived from TTR and/or Apo A-I. Some patients with knee OA, however, had unclassified amyloid deposits. One of our interesting observations concerned the different effects of aging on each type of amyloid formed. The frequency of formation of ATTR deposits clearly increased with age, but that of AApo A-I deposits decreased. Furthermore, we found that ∼16% of patients with knee OA developed ATTR/AApo A-I double deposits in the meniscus. Amyloid deposition may therefore be a common histopathological feature associated with knee OA. Also, aging may induce ATTR formation in the knee joint in elderly patients with knee OA, whereas AApo A-I formation may be inversely correlated with age.
淀粉样变性是一种蛋白质构象紊乱疾病，其中淀粉样纤维在细胞外间隙积聚并导致器官功能障碍。最近，在膝关节骨关节炎（OA）患者的膝关节淀粉样沉积物中鉴定出两种不同的淀粉样蛋白生成蛋白，即转甲状腺素蛋白（TTR）和载脂蛋白A-I（Apo A-I）。然而，与膝关节中这两种淀粉样沉积物相关的临床病理差异仍有待阐明。在此，我们研究了与膝关节OA相关的这些膝关节淀粉样沉积物的临床病理特征以及淀粉样沉积物的生化特性。我们发现，所有膝关节OA患者的膝关节中都有淀粉样沉积物，尤其是在半月板中，并且这些沉积物主要来源于TTR和/或Apo A-I。然而，一些膝关节OA患者有未分类的淀粉样沉积物。我们一项有趣的观察结果涉及衰老对每种类型淀粉样蛋白形成的不同影响。ATTR沉积物的形成频率随年龄明显增加，但AApo A-I沉积物的形成频率则降低。此外，我们发现约16%的膝关节OA患者在半月板中形成了ATTR/AApo A-I双重沉积物。因此，淀粉样沉积可能是与膝关节OA相关的常见组织病理学特征。此外，衰老可能在老年膝关节OA患者的膝关节中诱导ATTR形成，而AApo A-I的形成可能与年龄呈负相关。
