Hokama Akira, Kishimoto Kazuto, Nakamoto Manabu, Kobashigawa Chiharu, Hirata Tetsuo, Kinjo Nagisa, Kinjo Fukunori, Kato Seiya, Fujita Jiro
Akira Hokama, Kazuto Kishimoto, Tetsuo Hirata, Jiro Fujita, Department of Infectious, Respiratory, and Digestive Medicine, Faculty of Medicine, University of the Ryukyus, Okinawa 903-0125, Japan.
World J Gastrointest Endosc. 2011 Aug 16;3(8):157-61. doi: 10.4253/wjge.v3.i8.157.
Amyloidosis is a rare disorder, characterized by the extracellular deposition of an abnormal fibrillar protein, which disrupts tissue structure and function. Amyloidosis can be acquired or hereditary, and systemic or localized to a single organ, such as the gastrointestinal (GI) tract. Clinical manifestations may vary from asymptomatic to fatal forms. Primary amyloidosis (monoclonal immunoglobulin light chains, AL) is the most common form of amyloidosis. AL amyloidosis has been associated with plasma cell dyscrasias, such as, multiple myeloma. Secondary amyloidosis is caused by the deposition of fragments of the circulating acute-phase reactant, serum amyloid A protein (SAA). Common causes of AA amyloidosis are chronic inflammatory disorders. Although GI symptoms are usually nonspecific, histopathological patterns of amyloid deposition are associated with clinical and endoscopic features. Amyloid deposition in the muscularis mucosae, submucosa, and muscularis propria has been dominant in AL amyloidosis, leading to polypoid protrusions and thickening of the valvulae conniventes, whereas granular amyloid deposition mainly in the propria mucosae has been related to AA amyloidosis, resulting in the fine granular appearance, mucosal friability, and erosions. As a result, AL amyloidosis usually presents with constipation, mechanical obstruction, or chronic intestinal pseudo-obstruction while AA amyloidosis presents with diarrhea and malabsorption Amyloidotic GI symptoms are mostly refractory and have a negative impact on quality of life and survival. Diagnosing GI amyloidosis requires high suspicion of evaluating endoscopists. Because of the absence of specific treatments for reducing the abundance of the amyloidogenic precursor protein, we should be aware of certain associations between patterns of amyloid deposition and clinical and endoscopic features.
淀粉样变性是一种罕见的疾病，其特征是细胞外异常纤维状蛋白沉积，破坏组织结构和功能。淀粉样变性可分为获得性或遗传性，可累及全身或局限于单个器官，如胃肠道（GI）。临床表现可从无症状到致命形式不等。原发性淀粉样变性（单克隆免疫球蛋白轻链，AL）是最常见的淀粉样变性形式。AL淀粉样变性与浆细胞发育异常有关，如多发性骨髓瘤。继发性淀粉样变性是由循环急性期反应物血清淀粉样蛋白A（SAA）片段沉积引起的。AA淀粉样变性的常见病因是慢性炎症性疾病。虽然胃肠道症状通常不具有特异性，但淀粉样蛋白沉积的组织病理学模式与临床和内镜特征相关。在AL淀粉样变性中，黏膜肌层、黏膜下层和固有肌层的淀粉样蛋白沉积占主导地位，导致息肉样突起和皱襞增厚，而主要在固有黏膜层的颗粒状淀粉样蛋白沉积与AA淀粉样变性有关，导致黏膜出现细颗粒外观、黏膜脆性增加和糜烂。因此，AL淀粉样变性通常表现为便秘、机械性肠梗阻或慢性肠道假性梗阻，而AA淀粉样变性表现为腹泻和吸收不良。淀粉样变性的胃肠道症状大多难以治愈，对生活质量和生存率有负面影响。诊断胃肠道淀粉样变性需要内镜检查医生高度怀疑。由于缺乏减少淀粉样前体蛋白丰度的特异性治疗方法，我们应该了解淀粉样蛋白沉积模式与临床和内镜特征之间的某些关联。
