Dynamic analysis of human small intestinal microbiota after an ingestion of fermented milk by small-intestinal fluid perfusion using an endoscopic retrograde bowel insertion technique

ABSTRACT

Probiotic products have been shown to have beneficial effects on human hosts, but what happens in the gastrointestinal tract after its ingestion remains unclear. Our aim was to investigate the changes within the small intestines after a single intake of a fermented milk product containing a probiotic. We have periodically collected the small-intestinal fluids from the terminal ileum of seven healthy subjects for up to 7 h after ingestion by small-intestinal fluid perfusion using an endoscopic retrograde bowel insertion technique. The bacterial composition of the terminal ileum clearly revealed that the ingested probiotics (Lactobacillus casei strain Shirota: LcS and Bifidobacterium breve strain Yakult: BbrY) occupied the ileal microbiota for several hours, temporarily representing over 90% of the ileal microbiota in several subjects. Cultivation of ileal fluids showed that under a dramatic pH changes before reaching the terminal ileum, a certain number of the ingested bacteria survived (8.2 ± 6.4% of LcS, 7.8 ± 11.0% of BbrY). This means that more than 1 billion LcS and BbrY cells reached the terminal ileum with their colony-forming ability intact. These results indicate that there is adequate opportunity for the ingested probiotics to continuously stimulate the host cells in the small intestines. Our data suggest that probiotic fermented milk intake affects intestinal microbes and the host, explaining part of the process from the intake of probiotics to the exertion of their beneficial effects on the host.     

Effect of lactobacillus on the gut microfiora and barrier function of the rats with abdominal infection

AIM: To investigate the effect of probiotics supplemented by gut on the tight junctions of epithelial cells, barrier function and the microflora of rats with abdominal infection. METHODS: After the model of cecal ligation and perforation established, SD rats were divided into two groups: parenteral nutrition (PN) group and PN+probiotics (probiotics) group, PN solution was supplemented by neck vein and probiotics was delivered via the jejunostomy tube for five days. Vena cava blood and the homogenated tissue of liver, lung and mesenteric lymph nodes were cultured to determine the bacterial translocation rate (BTR). The ultrastructure of epithelial tight junctions and microvilli of the gut were observed by electron microscopy; occluding expression was measured by indirect-immune fluorescence method; anaerobic bacterial growth by anaerobic culture and DNA fingerprint of bacterial colonies of the feces by PCR. RESULTS: The quantity of lactobacteria and bifydobacteria in probiotics group was higher than that of PN group. The profiles of DNA fingerprint expression in probiotics group were similar to that in the normal group, a new 16S rDNA sequence appeared in the profile in PN group. The occludin expression, the integrality of the gut epithelial tight junctionand microvilli in probiotics group were improved as compared with PN group. The BTR and endotoxin in blood were reduced more significantly in probiotics group as compared with PN group.CONCLUSION: The probiotics could improve the gut microflora disturbance, increase occludin expression, maintain the gut epithelial tight junction and decrease the bacterial translocations rate.     

Multicenter randomized controlled trial of heat‐killed Lactobacillus acidophilus LB in patients with chronic diarrhea

OBJECTIVE: Chronic diarrhea is a common bowel disorder, and disturbance of intestinal microorganisms may play a role in its pathogenesis. The aim of this study was to assess the clinical efficacy of lyophilized heat‐killed Lactobacillus acidophilus LB compared with living lactobacilli in the treatment of chronic diarrhea. METHODS: One hundred and thirty‐seven patients with chronic diarrhea were randomly allocated to receive either a 4‐week course of two capsules of Lacteol Fort twice a day as the Lacteol group (69 patients completed the course) or a 4‐week course of five chewable tablets of Lacidophilin three times a day as the Lacidophilin group (64 patients completed the course). The frequency of stools was recorded quantitatively and the semiquantitative parameters such as stool consistency, abdominal pain, distension and feeling of incomplete evacuation were evaluated. RESULTS: At the second and fourth week of the treatment, the mean bowel frequency was significantly lower in the Lacteol group than in the Lacidophilin group (1.88 ± 1.24 vs 2.64 ± 1.12, 1.39 ± 0.92 vs 2.19 ± 1.05, respectively; P < 0.05). At the end of the treatment, the clinical symptoms were markedly improved in the Lacteol group. CONCLUSIONS: Lactobacillus acidophilus LB is more effective than living lactobacilli in the treatment of chronic diarrhea.     

An experimental study on ulcerative colitis as a potential target for probiotic therapy by Lactobacillus acidophilus with or without “olsalazine”

Traditional medical treatments for ulcerative colitis (UC) are still compromised by its adverse effects and not potent enough to keep in remission for long-term periods. So, new therapies that are targeted at specific disease mechanisms have the potential to provide more effective and safe treatments for ulcerative colitis. Probiotics is recently introduced as a therapy for ulcerative colitis. In the present study, Lactobacillus acidophilus was selected as a probiotic therapy to investigate its effects in oxazolone-induced colitis model in rats that mimics the picture in human. The rats were grouped (8 rats each) as normal control group (Group I), Group II served as untreated oxazolone-induced colitis, Group III oxazolone-induced colitis treated with probiotic L. acidophilus (1 × 10⁷ colony-forming units (CFU)/mL/day oral for 14 days), Group IV oxazolone-induced colitis treated with olsalazine (60 mg/kg/day oral for 14 days), Group V oxazolone-induced colitis treated with probiotic L. acidophilus and olsalazine in the same doses and duration. Disease activity index (DAI) was recorded, serum levels of C-reactive protein (CRP), tumor necrosis factor-α (TNF-α) and intrleukin-6 (IL-6) was assessed as inflammatory markers and the histopathological picture of the colon of each rat was studied. Disease activity index (DAI) showed significant positive correlation with the elevated serum levels of CRP (r = 0.741, p < 0.05), TNF-α (r = 0.802, p < 0.05) and IL-6 (r = 0.801, p < 0.05). Treatment with either L. acidophilus (group III) or olsalazine (group IV) resulted in significant reduction in serum levels of CRP, TNF-α and IL-6, as well as disease activity index (DAI). Treatment with combination of L. acidophilus and olsalazine (group V) offered more significant reduction in serum levels of CRP, TNF-α, IL-6 and disease activity index (DAI) when compared to either group II (untreated group), group III (treated with L. acidophilus) or group IV (treated with olsalazine). So, it was concluded that L. acidophilus probiotic could be recommended as adjuvant therapy in combination with olsalazine to achieve more effective treatment for ulcerative colitis. For application in human, this needs to be verified in further clinical studies.     

Rationale for probiotic treatment strategies in inflammatory bowel disease

Chronic inflammatory bowel diseases (IBD), such as Crohn’s disease and ulcerative colitis, are recurrent and aggressive inflammatory disorders that are most likely the result of an overly aggressive immune response to ubiquitous intestinal antigens in a genetically susceptible host. Despite decades of intense research, our knowledge of factors causing IBD remains incomplete and, therefore, conventional therapy to induce and maintain remission works in a symptomatic fashion, merely suppressing the immune response. Probiotic bacteria have long been known to confer health benefits, especially with regard to intestinal disorders. Although there is mounting evidence from in vitro and animal experiments supporting the use of probiotics in IBD, clinical trials have not provided definite evidence for the therapeutic effect of probiotic therapy in IBD to date. This is with the notable exception of pouchitis and the maintenance of remission in ulcerative colitis, whereas Crohn’s disease and active ulcerative colitis do not seem amenable to probiotic intervention. The next 5 years will see more trials targeting specific clinical settings using tailor-made probiotic combinations, taking into account our increasing knowledge of individual probiotic properties and the diversity of these microorganisms.     

Characterization of a probiotic-derived soluble protein which reveals a mechanism of preventive and treatment effects of probiotics on intestinal inflammatory diseases

The beneficial effects of probiotics have been demonstrated in many diseases, such as inflammatory bowel disease. The known mechanisms for probiotic action include blocking pathogenic bacterial effects, enhancing the innate immunity and decreasing pathogen-induced inflammation, and promoting intestinal epithelial cell survival, barrier function, and protective responses. We purified and cloned a Lactobacillus rhamnosus GG (LGG)-derived soluble protein, p40. This protein ameliorated cytokine-induced apoptosis in intestinal epithelial cells through activation of the EGF receptor and its down-stream target, Akt. By using special hydrogel beads to protect p40 from degradation, we showed that p40 reduced intestinal epithelial apoptosis and preserved barrier function in the colon epithelium in an EGF receptor-dependent manner, thereby preventing and treating intestinal inflammation in mouse models of colitis. Further works regarding structural analysis of p40, regulation of EGF receptor activation and immunoregulatory effects by p40 are discussed. These results may provide insights into the clinical application of probiotics for intestinal inflammatory disorders.     

Commensal-pathogen interactions in the intestinal tract

The intestinal microbiota are pivotal in determining the developmental, metabolic and immunological status of the mammalian host. However, the intestinal tract may also accommodate pathogenic organisms, including helminth parasites which are highly prevalent in most tropical countries. Both microbes and helminths must evade or manipulate the host immune system to reside in the intestinal environment, yet whether they influence each other’s persistence in the host remains unknown. We now show that abundance of Lactobacillus bacteria correlates positively with infection with the mouse intestinal nematode parasite, Heligmosomoides polygyrus, as well as with heightened regulatory T cell (Treg) and Th17 responses. Moreover, H. polygyrus raises Lactobacillus species abundance in the duodenum of C57BL/6 mice, which are highly susceptible to H. polygyrus infection, but not in BALB/c mice, which are relatively resistant. Sequencing of samples at the bacterial gyrB locus identified the principal Lactobacillus species as L. taiwanensis, a previously characterized rodent commensal. Experimental administration of L. taiwanensis to BALB/c mice elevates regulatory T cell frequencies and results in greater helminth establishment, demonstrating a causal relationship in which commensal bacteria promote infection with an intestinal parasite and implicating a bacterially-induced expansion of Tregs as a mechanism of greater helminth susceptibility. The discovery of this tripartite interaction between host, bacteria and parasite has important implications for both antibiotic and anthelmintic use in endemic human populations.     

脐血LAK细胞活性的诱导及调节

应用~(51)Cr释放试验研究了人脐血LAK细胞对K562细胞及Raji细胞的杀伤率,以及OK-432、干酪乳酸杆菌对脐血LAK细胞的调节作用。结果表明,rIL-2可诱导人脐血淋巴细胞产生LAK细胞活性,杀伤Raji细胞的能力由10%增至50%,对K562细胞的杀伤力也明显增强,统计学处理有显著意义。培养4天的LAK细胞杀伤力最强,杀伤率随效靶比例的增加而增强。OK-432及干酪乳酸杆菌均能增强rIL-2诱导的脐血LAK细胞的抗瘤活性。     

高纯度诊断用乳酸脱氢酶的制备和酶促反应

设计并优化了植物乳杆茵发酵制备高纯度诊断用乳酸脱氢酶的技术路线．从培育的厌氧型植物乳杆茵中粗提乳酸脱氢酶制备液，经过DEAE Sepharose F．F．离子交换层析、Phenyl Sepharose6 F．F．疏水层析及Sephadex G-25 Fine凝胶过滤等方法进行分离纯化，比酶活达1096．8U／mg，纯度达88％，纯化倍数达到21．4倍，酶活力回收率为53．9％；高效液相色谱和SDS-PAGE电泳结果显示制得乳酸脱氢酶相对分子质量约为80000，含有两个亚基，每个亚基分子量约为39000．     

Impaired secretory immunity in dystrophic epidermolysis bullosa

Dystrophic epidermolysis bullosa is a congenital disorder characterized by blistering of the skin and oral mucosa. This study investigated the hypothesis that children with dystrophic epidermolysis bullosa have impaired oral secretory immunity. Immunoglobulin A (IgA), secretory IgA and IgG concentrations, and IgA and secretory IgA antibody levels to Candida albicans, Lactobacillus casei and Streptococcus mutans were measured in whole saliva from 22 children with dystrophic epidermolysis bullosa and 22 matched controls. Salivary total IgA and total IgG concentrations were significantly raised in dystrophic epidermolysis bullosa due to serum leakage from oral blistering, but the converse was seen with secretory IgA. This suggestion of a mucosal immune defect was supported by decreased secretory IgA antibody responses to all three microorganisms tested. This apparent defect in secretory immunity in dystrophic epidermolysis bullosa may be due to mucosal involvement and damage resulting in impaired antigen sampling in mucosal associated lymphoid tissue or to impaired transport of secretory IgA across the salivary gland mucosa.