Saavedra Jose M
Division of Gastroenterology and Nutrition, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
Nutr Clin Pract. 2007 Jun;22(3):351-65. doi: 10.1177/0115426507022003351.
The use of probiotics (ingested microbes that can modify intestinal microbial populations in a way that benefit the host) has moved from concept to actual demonstration of specific benefits by specific microorganisms for specific populations. It is increasingly clear that these benefits to the host are mostly mediated by the profound effect that intestinal microflora (microbiota) have on gut barrier function and host immune response. Intestinal bacteria are more numerous than the human cells of the host that harbors them. Despite having many potential pathogens in this microflora, humans do not routinely get infected. It is no coincidence that gut-associated immune tissue constitutes approximately 80% of all immunologically active cells in the human host. The gut interacts with intestinal bacteria, both resident and ingested, to develop protective mechanisms (via improving gut barrier function and immune stimulation for defense) and appropriate, nonexaggerated responses (via immune modulation and immune tolerance) to support host health. The mechanisms of this interaction between host and bacteria are increasingly being unraveled and in great part explain the clinical benefits that have been reported with specific probiotic bacteria by enhancing host defense mechanisms (such as for treatment and prevention of viral diarrhea and reducing risk of necrotizing enterocolitis), mitigating antibiotic-associated diarrhea, and modulating host immune response (such as in allergic disease).
益生菌(摄入后能以有益于宿主的方式改变肠道微生物群落的微生物)的应用已从概念走向特定微生物对特定人群产生特定益处的实际证明。越来越明显的是,这些对宿主的益处大多是由肠道微生物群(微生物区系)对肠道屏障功能和宿主免疫反应产生的深远影响介导的。肠道细菌的数量比寄居它们的宿主的人类细胞还要多。尽管这种微生物区系中有许多潜在病原体,但人类通常不会受到感染。肠道相关免疫组织约占人类宿主所有免疫活性细胞的80%,这并非巧合。肠道与常驻和摄入的肠道细菌相互作用,以形成保护机制(通过改善肠道屏障功能和进行免疫刺激来防御)以及适当、不过度的反应(通过免疫调节和免疫耐受)来支持宿主健康。宿主与细菌之间这种相互作用的机制正日益被揭示,并且在很大程度上解释了特定益生菌所报告的临床益处,这些益处包括增强宿主防御机制(如用于治疗和预防病毒性腹泻以及降低坏死性小肠结肠炎的风险)、减轻抗生素相关性腹泻以及调节宿主免疫反应(如在过敏性疾病中)。