Viggiano D, Ianiro G, Vanella G, Bibbò S, Bruno G, Simeone G, Mele G
Primary Care Pediatrician, ASL Salerno, Italy.
Eur Rev Med Pharmacol Sci. 2015;19(6):1077-85.
The gut barrier is a functional unit, organized as a multi-layer system, made up of two main components: a physical barrier surface, which prevents bacterial adhesion and regulates paracellular diffusion to the host tissues, and a deep functional barrier, that is able to discriminate between pathogens and commensal microorganisms, organizing the immune tolerance and the immune response to pathogens. Other mechanisms, such as gastric juice and pancreatic enzymes (which both have antibacterial properties) participate in the luminal integrity of the gut barrier. From the outer layer to the inner layer, the physical barrier is composed of gut microbiota (that competes with pathogens to gain space and energy resources, processes the molecules necessary to mucosal integrity and modulates the immunological activity of deep barrier), mucus (which separates the intraluminal content from more internal layers and contains antimicrobial products and secretory IgA), epithelial cells (which form a physical and immunological barrier) and the innate and adaptive immune cells forming the gut-associated lymphoid tissue (which is responsible for antigen sampling and immune responses). Disruption of the gut barrier has been associated with many gastrointestinal diseases, but also with extra-intestinal pathological condition, such as type 1 diabetes mellitus, allergic diseases or autism spectrum disorders. The maintenance of a healthy intestinal barrier is therefore of paramount importance in children, for both health and economic reasons. Many drugs or compounds used in the treatment of gastrointestinal disorders act through the restoration of a normal intestinal permeability. Several studies have highlighted the role of probiotics in the modulation and reduction of intestinal permeability, considering the strong influence of gut microbiota in the modulation of the function and structure of gut barrier, but also on the immune response of the host. To date, available weapons for the maintenance and repair of gut barrier are however few, even if promising. Considerable efforts, including both a better understanding of the gut barrier features and mechanisms in health and disease, and the development of new pharmacological approaches for the modulation of gut barrier components, are needed for the prevention and treatment of gastrointestinal and extraintestinal diseases associated with gut barrier impairment.
肠道屏障是一个功能单元，组织为多层系统，由两个主要成分组成：一个物理屏障表面，可防止细菌黏附并调节经细胞旁向宿主组织的扩散；以及一个深层功能屏障，能够区分病原体和共生微生物，构建免疫耐受和对病原体的免疫反应。其他机制，如胃液和胰酶（两者均具有抗菌特性）也参与肠道屏障的管腔完整性维护。从外层到内层，物理屏障由肠道微生物群（与病原体竞争空间和能量资源，处理黏膜完整性所需分子并调节深层屏障的免疫活性）、黏液（将管腔内物质与更内层隔开，并含有抗菌产物和分泌型IgA）、上皮细胞（形成物理和免疫屏障）以及构成肠道相关淋巴组织的固有免疫细胞和适应性免疫细胞（负责抗原采样和免疫反应）组成。肠道屏障的破坏不仅与许多胃肠道疾病有关，还与肠外病理状况有关，如1型糖尿病、过敏性疾病或自闭症谱系障碍。因此，出于健康和经济原因，维持健康的肠道屏障对儿童至关重要。许多用于治疗胃肠道疾病的药物或化合物通过恢复正常的肠道通透性起作用。多项研究强调了益生菌在调节和降低肠道通透性方面的作用，考虑到肠道微生物群对肠道屏障功能和结构的调节有很大影响，同时也对宿主的免疫反应有影响。然而，迄今为止，用于维持和修复肠道屏障的有效手段仍然很少，尽管前景乐观。为了预防和治疗与肠道屏障受损相关的胃肠道和肠外疾病，需要做出相当大的努力，包括更好地了解健康和疾病状态下肠道屏障的特征和机制，以及开发调节肠道屏障成分的新药理学方法。
