No effect of oral treatment with an intestinal bacterial strain, Lactobacillus rhamnosus (ATCC 53103), on birch-pollen allergy: a placebo-controlled double-blind study

BACKGROUND: Oral probiotic bacteriotherapy with Lactobacillus rhamnosus has given promising results in small children with food allergy. We studied the effects of similar therapy in teenagers and young adults, who were allergic to birch pollen and apple food and had intermittent symptoms of atopic allergy and/or mild asthma. METHODS: We conducted a double-blind, placebo-controlled study, in which respiratory and eye symptoms and use of medications in two groups were compared. Open oral challenge tests with a slice of apple were performed trice: before, during and after the birch-pollen season. There were 18 patients in each group. They used Lactobacillus rhamnosus for 5.5 months; 2.5 months before the pollen season, 1 month during the season (May), and 2 months after. RESULTS: The results were negative. The treatment did not alleviate the symptoms of the patients or reduce their use of medication during the birch-pollen season or the subsequent 2 months. The treatment did not significantly affect the symptoms caused by apple in the oral challenge tests. CONCLUSIONS: We found no indication of a beneficial treatment effect in our patients. As the number of patients was relatively small, conclusions should be drawn with caution.     

Intestinal colonization resistance

Dense, complex microbial communities, collectively termed the microbiota, occupy a diverse array of niches along the length of the mammalian intestinal tract. During health and in the absence of antibiotic exposure the microbiota can effectively inhibit colonization and overgrowth by invading microbes such as pathogens. This phenomenon is called ‘colonization resistance’ and is associated with a stable and diverse microbiota in tandem with a controlled lack of inflammation, and involves specific interactions between the mucosal immune system and the microbiota. Here we overview the microbial ecology of the healthy mammalian intestinal tract and highlight the microbe–microbe and microbe–host interactions that promote colonization resistance. Emerging themes highlight immunological (T helper type 17/regulatory T‐cell balance), microbiota (diverse and abundant) and metabolic (short‐chain fatty acid) signatures of intestinal health and colonization resistance. Intestinal pathogens use specific virulence factors or exploit antibiotic use to subvert colonization resistance for their own benefit by triggering inflammation to disrupt the harmony of the intestinal ecosystem. A holistic view that incorporates immunological and microbiological facets of the intestinal ecosystem should facilitate the development of immunomodulatory and microbe‐modulatory therapies that promote intestinal homeostasis and colonization resistance.     

微生物群与肠道炎症

在数百万年的时间里,哺乳动物进化出与肠道菌群间一个精密的共生关系。不断增加的证据表明微生物群平衡失调可以促进人类疾病的发展,其中包括不断增加的炎性肠炎。修复宿主-微生物相互作用是一种有效的阻止和治疗疾病的策略。在本文中,我们着重描述了在正常生理状况和肠道炎症背景下肠道微生物群的功能,着眼于宿主和微生物复杂关系的机理和病原基础。尽管有目前研究进展,但肠菌研究还面临很多挑战,缩小基础科学和临床应用之间的差距仍然很困难。我们认识到如果缺少肠道菌群及其对哺乳动物生理影响的深入理解,共生菌用于治疗（＂从肠菌到药物＂）的前景便无从谈起,所以本文也讨论用于操控肠道微生物群的临床治疗策略。     

Bacteroides ovatus ATCC 8483 monotherapy is superior to traditional fecal transplant and multi-strain bacteriotherapy in a murine colitis model

ABSTRACT

Background and aims

Bacteriotherapy aimed at addressing dysbiosis may be therapeutic for Inflammatory Bowel Diseases (IBDs). We sought to determine if defined Bacteroides-based bacteriotherapy could be an effective and consistent alternative to fecal microbiota transplantation (FMT) in a murine model of IBD.     

The crosstalk between gut barrier impairment,mitochondrial dysfunction,and microbiota alterations in people living with HIV

Functional and structural damage of the intestinal mucosal barrier significantly contribute to translocation of gut microbial products into the bloodstream and are largely involved in HIV-1 associated chronic immune activation. This microbial translocation is largely due to a progressive exhaustion of intestinal macrophage phagocytic function, which leads to extracellular accumulation of microbial derived components and results in HIV-1 disease progression. This study aims to better understand whether the modulation of gut microbiota promotes an intestinal immune restoration in people living with HIV (PLWH). Long-term virologically suppressed PLWH underwent blood, colonic, and fecal sampling before (T0) and after 6 months (T6) of oral bacteriotherapy. Age- and gender-matched uninfected controls (UC) were also included. 16S rRNA gene sequencing was applied to all participants' fecal microbiota. Apoptosis machinery, mitochondria, and apical junctional complex (AJC) morphology and physiological functions were analyzed in gut biopsies. At T0, PLWH showed a different pattern of gut microbial flora composition, lower levels of occludin (p = 0.002) and zonulin (p = 0.01), higher claudin-2 levels (p = 0.002), a reduction of mitochondria number (p = 0.002), and diameter (p = 0.002), as well as increased levels of lipopolysaccharide (LPS) (p = 0.018) and cCK18 (p = 0.011), compared to UC. At T6, an increase in size (p = 0.005) and number (p = 0.008) of mitochondria, as well as amelioration in AJC structures (p < 0.0001) were observed. Restoration of bacterial richness (Simpson index) and biodiversity (Shannon index) was observed in all PLWH receiving oral bacteriotherapy (p < 0.05). Increased mitochondria size (p = 0.005) and number (p = 0.008) and amelioration of AJC structure (p < 0.0001) were found at T6 compared to T0. Moreover, increased occludin and zonulin concentration were observed in PLWH intestinal tracts and decreased levels of claudin-2, LPS, and cCK18 were found after oral bacteriotherapy (T0 vs. T6, p < 0.05 for all these measures). Oral bacteriotherapy supplementation might restore the balance of intestinal flora and support the structural and functional recovery of the gut mucosa in antiretroviral therapy treated PLWH.     

Effect of probiotic lozenges on inflammatory reactions and oral biofilm during experimental gingivitis

Abstract

Aim. Probiotic bacteria have been introduced for prevention and treatment of periodontal diseases. The aim was to assess if daily oral administration of probiotic bacteria could influence the inflammatory response and the composition of supragingival plaque in an experimental gingivitis model. Materials and methods. Eighteen healthy female adults volunteered after informed consent. A double-blind randomized placebo-controlled cross-over design was used. The buccal surface of first molars was used as experimental sites. A mouth-guard covering the first premolar to second molar was used when brushing, preventing accidental cleaning during 3 weeks of plaque accumulation. Lozenges containing L. reuteri (ATCC55730 and ATCC PTA5289) or placebo were taken twice a day. During the run-in and washout periods, professional tooth cleaning was performed 5 days/week. At baseline and follow-up, plaque index, gingival index and bleeding on probing were recorded. Samples of gingival crevicular fluid (GCF) were analysed for concentration of seven inflammatory mediators. Bacterial samples were processed with checkerboard DNA/DNA-hybridization. Results. All subjects presented a local plaque accumulation and developed manifest gingivitis at the test sites during the intervention periods. The volume of GCF increased in both groups but was statistically significant only in the placebo group (p < 0.05). The concentrations of IL1-β and IL-18 increased significantly (p < 0.05), while IL-8 and MIP1-β decreased (p < 0.05). No differences were displayed between test and placebo. Likewise, the microbial composition did not differ between the groups. Conclusion. Daily intake of probiotic lozenges did not seem to significantly affect the plaque accumulation, inflammatory reaction or the composition of the biofilm during experimental gingivitis.