Johnston S D, Smye M, Watson R P
Department of Gastroenterology, Belfast City Hospital, Northern Ireland.
Clin Lab. 2001;47(3-4):143-50.
Intestinal permeability tests have been used to screen for a wide range of small intestinal diseases, including coeliac disease and enteric infections. Several probe molecules have been used to investigate intestinal permeability including monosaccharides, disaccharides, 51Cr-EDTA and polyethyleneglycol. While many factors may affect intestinal permeability tests, the use of two probe molecules, for example, lactulose and mannitol, and the expression of the result as a ratio minimises the effects of these extraneous factors. Rendering the test solution hyperosmolar was also found to increase the sensitivity of the test in detecting coeliac disease. Intestinal permeability is characteristically elevated in untreated coeliac disease, with a sensitivity of up to 96% for the dual sugar techniques. The reason for this is a consistent increase in the absorption of lactulose (via the paracellular route) due to increased "leakiness" of the intestine and a reduction in the absorption of mannitol (via the transcellular route) due to a reduction in surface area as a result of villous atrophy. The intestinal permeability test allows subjects to be selected for jejunal biopsy in whom the clinical features are compatible with coeliac disease and in timing a follow-up biopsy. It has been postulated that raised intestinal permeability may be involved in the pathogenesis of coeliac disease. Recently, serum measurements of the probe molecules may have a valuable role, particularly in paediatric patients. Sucrose permeability has also been proposed as an accurate marker of adult coeliac disease and shows promise as a noninvasive test.
肠道通透性测试已被用于筛查多种小肠疾病，包括乳糜泻和肠道感染。几种探针分子已被用于研究肠道通透性，包括单糖、双糖、51Cr-乙二胺四乙酸和聚乙二醇。虽然许多因素可能影响肠道通透性测试，但使用两种探针分子，例如乳果糖和甘露醇，并将结果表示为比率可将这些外部因素的影响降至最低。还发现使测试溶液呈高渗状态可提高检测乳糜泻的测试灵敏度。未经治疗的乳糜泻患者的肠道通透性通常会升高，双糖技术的灵敏度高达96%。其原因是由于肠道“渗漏”增加，乳果糖（通过细胞旁途径）的吸收持续增加，以及由于绒毛萎缩导致表面积减少，甘露醇（通过跨细胞途径）的吸收减少。肠道通透性测试可用于选择临床特征与乳糜泻相符的患者进行空肠活检，并确定随访活检的时间。据推测，肠道通透性升高可能参与乳糜泻的发病机制。最近，探针分子的血清检测可能具有重要作用，尤其是在儿科患者中。蔗糖通透性也被提议作为成人乳糜泻的准确标志物，并有望成为一种非侵入性检测方法。
