Fine and ultrafine particles of the diet: influence on the mucosal immune response and association with Crohn's disease
Fine and ultrafine particles of the diet: influence on the mucosal immune response and association with Crohn's disease
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DOI：
10.1079/pns2001134
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发表时间：
2002-02-01
影响因子：
7
通讯作者：
Powell, JJ
中科院分区：
文献类型：
--
作者：
Lomer, MCE;Thompson, RPH;Powell, JJ
克罗恩病是一种现代西方疾病，其特征是胃肠道的透壁炎症。它的病因尚不清楚，但有证据表明它是遗传倾向和环境因素共同作用的结果。细菌大小的微粒（0.1-1.0μm）是模型抗原介导的免疫反应的有效佐剂，并且与疾病的关系越来越密切。二氧化钛和硅铝酸盐微粒积聚在人类肠道相关淋巴组织的巨噬细胞中，在此处观察到克罗恩病病变的最早迹象。膳食微粒有内源性或外源性。内源性微粒占主导地位，是磷酸钙（最有可能是羟基磷灰石），由于肠液中钙和磷酸盐的分泌，磷酸钙在中远端胃肠道的管腔中沉淀。外源性膳食微粒是污染物（土壤和/或灰尘）和食品添加剂。例如，二氧化钛是一种食品着色剂，硅铝酸盐是抗结块剂，尽管一些硅铝酸盐作为天然污染物存在。仅食品添加剂一项就占每人每天摄入约 10(12) 个颗粒。讨论了外源性和内源性膳食微粒在促进胃肠粘膜吞噬作用的耐受性或免疫反应中的作用的可能机制。在一项双盲随机试点研究中，我们表明，低钙和外源性微粒饮食似乎可以减轻回肠克罗恩病的症状，并显着（P = 0.002）改善克罗恩病活动指数。一项多中心试验和细胞水平的进一步机制研究正在进行中。
Crohn's disease is a modem Western disease characterised by transmural inflammation of the gastrointestinal tract. It is of unknown aetiology, but evidence suggests that it results from a combination of genetic predisposition and environmental factors. Bacterial-sized microparticles (0.1-1.0 mum) are potent adjuvants in model antigen-mediated immune responses and are increasingly associated with disease. Microparticles of TiO2 and aluminosilicate accumulate in macrophages of human gut-associated lymphoid tissue where the earliest signs of lesions in Crohn's disease are observed. Dietary microparticles are of endogenous or exogenous origin. Endogenous microparticles dominate and are calcium phosphate (most probably hydroxyapatite), which precipitates in the lumen of the mid-distal gastrointestinal tract due to secretion of Ca and phosphate in the succus entericus, Exogenous dietary microparticles are contaminants (soil and/or dust) and food additives. TiO2, for example, is a food colourant, and alummosilicates are anti-caking agents, although some aluminosilicates occur as natural contaminants. Food additives alone account for ingestion of approximately 10(12) particles/person per d. Possible mechanisms for the role of exogenous and endogenous dietary microparticles in promoting toleragenic or immune responses of gastrointestinal mucosal phagocytosis are discussed. In a double-blind randomised pilot study we have shown that a diet low in Ca and exogenous microparticles appears to alleviate the symptoms of ileal Crohn's disease, with a significant (P = 0.002) improvement in the Crohn's disease activity index. A multi-centre trial and further mechanistic studies at the cellular level are underway.