University of Canberra Research Institute for Sport and Exercise (UCRISE), Canberra, ACT, Australia.
Discipline of Physiotherapy, University of Canberra, Canberra, ACT, Australia.
Scand J Med Sci Sports. 2018 May;28(5):1506-1513. doi: 10.1111/sms.13051. Epub 2018 Feb 8.
Metabolic factors such as cholesterol appear to play an important role in the development of Achilles tendinopathy. There is, however, no morphologic proof explaining the link between high cholesterol and tendinopathy. As apolipoprotein A1 (Apo-A1) is essential for reverse cholesterol transport, it may be related to cholesterol overload in tendon. Nothing is known about Apo-A1 expression in tendon tissue. We examined the distribution of Apo-A1 protein in biopsies from normal and tendinopathy-affected human Achilles tendons, and APOA1 mRNA production from cultured human hamstring tenocytes. Specific immunoreactions for Apo-A1 were detected. The tenocytes showed specific Apo-A1 immunoreactions. These reactions were usually distinct in the tendinopathy specimens. While the tendinopathy specimens often showed granular/small deposit reactions, the slender tenocytes of control specimens did not show this pattern. The magnitude of Apo-A1 immunoreactivity was especially marked in the tendinopathy specimens, as there is a high number of tenocytes. Reactions were also seen in the walls of blood vessels located within the tendon tissue proper of both the normal and tendinopathy tendons and within the peritendinous/fatty tissue of the tendinopathy tendons. The reactions were predominantly in the form of deposit reactions within the smooth muscle layer of the vessel walls. Cultured hamstring tenocytes produced APOA1 mRNA. We demonstrated the presence of Apo-A1 in human tendon tissue. This suggests there may be a link between Achilles tendinopathy and cholesterol metabolism. We hypothesize that Apo-A1 may be important for tenocyte and blood vessel function within tendons.
代谢因素，如胆固醇，似乎在跟腱病的发生发展中起着重要作用。然而，没有形态学证据可以解释胆固醇与跟腱病之间的联系。载脂蛋白 A1（Apo-A1）是胆固醇逆向转运所必需的，它可能与肌腱中的胆固醇过载有关。目前还不知道肌腱组织中 Apo-A1 的表达情况。我们检测了正常和跟腱病患者跟腱活检组织中 Apo-A1 蛋白的分布，以及培养的人半腱肌肌腱细胞中 APOA1 mRNA 的产生。检测到了 Apo-A1 的特异性免疫反应。肌腱细胞显示出特异性的 Apo-A1 免疫反应。这些反应在跟腱病标本中通常更为明显。虽然跟腱病标本常显示颗粒/小沉积反应，但对照组的细长肌腱细胞没有这种模式。由于肌腱细胞数量较多，Apo-A1 免疫反应的强度在跟腱病标本中尤为明显。在正常和跟腱病跟腱的腱组织本身以及跟腱病跟腱的腱周/脂肪组织内的血管壁中也观察到了反应。反应主要以血管壁平滑肌层内沉积反应的形式出现。培养的半腱肌肌腱细胞产生 APOA1 mRNA。我们证明了 Apo-A1 存在于人类肌腱组织中。这表明跟腱病和胆固醇代谢之间可能存在联系。我们假设 Apo-A1 可能对肌腱内的肌腱细胞和血管功能很重要。
