Chinese herbal medicines for treating ulcerative colitis via regulating gut microbiota-intestinal immunity axis

Ulcerative colitis(UC)is one of types of inflammatory bowel disease with high recurrence.Recent studies have highlighted that microbial dysbiosis as well as abnormal gut immunity are crucial factors that initiate a series of inflammatory responses in the UC.Modulating the gut microbiota-intestinal immunity loop has been suggested as one of key strategies for relieving UC.Many Chinese herbal medicines including some of single herb,herbal formulas and the derived constituents have been reported with protective effect against UC through modulating gut microbiome and intestinal immunity.Some clinical trials have shown promising results.This review thus focused on the current knowledge on using Chinese herbal medicines for treating UC from the mechanism aspects of regulating intestinal homeostasis involving microbiota and gut immunity.The existing clinical trials are also summarized.

Olive oil ameliorate allergic response in ovalbumin-induced food allergy mouse by promoting intestinal mucosal immunity

The numerous health benefits of olive oil are widely known,however,it also provides anti-allergic properties that have not yet been fully defined.In this study,the anti-allergic activity of olive oil was evaluated by analyzing the clinical symptoms and immune-related factors in BALB/c mice that had ingested600 mg/(kg·day)olive oil for two weeks prior to the evaluation.An allergy model was subsequently constructed for analysis,the results of which showed that the olive oil reduced the scores of allergic symptoms in the mice,and up-regulated the hypothermia and the decline in the immune organ index.Moreover,fewer allergy-related cytokines and reduced intestinal inflammation was discovered in the olive oil-treated group.In addition,analysis of intestinal mucosal immune-related factors revealed that the olive oil promoted the expression of intestinal tight junction proteins(Claudin-1,Occludin,and ZO-1)and IL-22,and helped maintain the integrity of the intestinal epithelial physical barrier.Increased levels of mucin 2 andβ-defensin were also found in the intestinal mucus of the olive oil-treated mice.These findings suggest that the oral administration of olive oil effectively attenuated the ovalbumin-induced allergic immune response in the mice,and had a positive effect on intestinal epithelial mucosal immunity.

Oleanolic acid improved intestinal immune function by activating and potentiating bile acids receptor signaling in E. coli-challenged piglets

Background Infection with pathogenic bacteria during nonantibiotic breeding is one of the main causes of animal intestinal diseases.Oleanolic acid(OA)is a pentacyclic triterpene that is ubiquitous in plants.Our previous work demonstrated the protective effect of OA on intestinal health,but the underlying molecular mechanisms remain unclear.This study investigated whether dietary supplementation with OA can prevent diarrhea and intestinal immune dysregulation caused by enterotoxigenic Escherichia coli(ETEC)in piglets.The key molecular role of bile acid receptor signaling in this process has also been explored.Results Our results demonstrated that OA supplementation alleviated the disturbance of bile acid metabolism in ETEC-infected piglets(P<0.05).OA supplementation stabilized the composition of the bile acid pool in piglets by regulating the enterohepatic circulation of bile acids and significantly increased the contents of UDCA and CDCA in the ileum and cecum(P<0.05).This may also explain why OA can maintain the stability of the intestinal microbiota structure in ETEC-challenged piglets.In addition,as a natural ligand of bile acid receptors,OA can reduce the severity of intestinal inflammation and enhance the strength of intestinal epithelial cell antimicrobial programs through the bile acid receptors TGR5 and FXR(P<0.05).Specifically,OA inhibited NF-κB-mediated intestinal inflammation by directly activating TGR5 and its downstream c AMP-PKA-CREB signaling pathway(P<0.05).Furthermore,OA enhanced CDCA-mediated MEK-ERK signaling in intestinal epithelial cells by upregulating the expression of FXR(P<0.05),thereby upregulating the expression of endogenous defense molecules in intestinal epithelial cells.Conclusions In conclusion,our findings suggest that OA-mediated regulation of bile acid metabolism plays an important role in the innate immune response,which provides a new diet-based intervention for intestinal diseases caused by pathogenic bacterial infections in piglets.

Regional Effect of APS-sEPS on Intestinal Structure and Mucosal Immunity in Mice

[Objectives]The aim of this study was to investigate the effects of APS-sEPS(a polysaccharide compound of Astragalus polysaccharides and sulfated Epimedium polysaccharide)on intestinal mucosal immunity and structural morphology.[Methods]Firstly,the diarrhea model was established using the optimal dose of magnesium sulfate in mice.Then,the diarrhea mice were randomly divided into three groups and given either physiological saline(diarrhea model group)or injected with APS-sEPS or APS.The normal mice were selected as a control group.After administration,the duodenum,jejunum and ileum were processed microtome section,and observed for describing the small intestine morphology,villus height and crypt depth.The tissue homogenates of the duodenum,jejunum and ileum were gathered to detect the changes of sIgA,IL-4 and IL-10.[Results]The results indicated that APS-sEPS could effectively relieve diarrhea in mice.In the APS-sEPS group,the villus heights of duodenum,jejunum and ileum were increased and the depth of crypt was reduced.The contents of IL-4,IL-10 and sIgA in jejunum and ileum in APS-sEPS group were significantly higher than that in the control group(P<0.05).[Conclusions]These results indicated that APS-sEPS promoted the recovery of intestinal morphological structure and enhanced the mucosa immunity of the small intestine.

Phasic study of intestinal homeostasis disruption in experimental intestinal obstruction

AIM: To investigate the phasic alteration of intestinal homeostasis in an experimental model of intestinal obstruction.

Moxibustion inhibits interleukin-12 and tumor necrosis factor alpha and modulates intestinal flora in rat with ulcerative colitis

AIM: To investigate the effect of moxibustion on intestinal flora and release of interleukin-12 (IL-12) and tumor necrosis factor-α (TNF-α) from the colon in rat with ulcerative colitis (UC). METHODS: A rat model of UC was established by local stimulation of the intestine with supernatant from colonic contents harvested from human UC patients. A total of 40 male Sprague-Dawley rats were randomly divided into the following groups: normal (sham), model (UC), herb-partition moxibustion (HPM-treated), and positive control sulfasalazine (SA-treated). Rats treated with HPM received HPM at acupuncture points ST25 and RN6, once a day for 15 min, for a total of 8 d. Rats in the SA group were perfused with SA twice a day for 8 d. The colonic histopathology was observed by hematoxylin-eosin. The levels of intestinal flora, including Bifidobacterium, Lactobacillus, Escherichia coli (E. coli), and Bacteroides fragilis (B. fragilis), were tested by real-time quantitative polymerase chain reaction to detect bacterial 16S rRNA/DNA in order to determine DNA copy numbers of each specific species. Immunohistochemical assays were used to observe the expression of TNF-α and IL-12 in the rat colons. RESULTS: HPM treatment inhibited immunopathology in colonic tissues of UC rats; the general morphological score and the immunopathological score were significantly decreased in the HPM and SA groups compared with the model group [3.5 (2.0-4.0), 3.0 (1.5-3.5) vs 6.0 (5.5-7.0), P < 0.05 for the general morphological score, and 3.00 (2.00-3.50), 3.00 (2.50-3.50) vs 5.00 (4.50-5.50), P < 0.01 for the immunopathological score]. As measured by DNA copy number, we found that Bifidobacterium and Lactobacillus, which are associated with a healthy colon, were significantly higher in the HPM and SA groups than in the model group (1.395 ± 1.339, 1.461 ± 1.152 vs 0.045 ± 0.036, P < 0.01 for Bifidobacterium, and 0.395 ± 0.325, 0.851 ± 0.651 vs 0.0015 ± 0.0014, P < 0.01 for Lactobacillus). On the other hand, E. coli and B. fragilis, which are associated with an inflamed colon, were significantly lower in the HPM and SA groups than in the model group (0.244 ± 0.107, 0.628 ± 0.257 vs 1.691 ± 0.683, P < 0.01 for E. coli, and 0.351 ± 0.181, 0.416 ± 0.329 vs 1.285 ± 1.039, P < 0.01 for B. fragilis). The expression of TNF-α and IL-12 was decreased after HPM and SA treatment as compared to UC model alone (4970.81 ± 959.78, 6635.45 ± 1135.16 vs 12333.81 ± 680.79, P < 0.01 for TNF-α, and 5528.75 ± 1245.72, 7477.38 ± 1259.16 vs 12550.29 ± 1973.30, P < 0.01 for IL-12). CONCLUSION: HPM treatment can regulate intestinal flora and inhibit the expression of TNF-α and IL-12 in the colon tissues of UC rats, indicating that HPM can improve colonic immune response.

The Influence of Chinese Medicinal Herb on Chicken Immune Organs and Small Intestinal Mucosa Immune Organization

[Objective] The aim was to explore the mechanism of Chinese medicinal herb to enhance the body＇s immune. [Method] The quantitative distribution of immunocytes in chicken small intestinal mucosa lymphoid tissue-secretory type immune globulin cell A were dynamic observed to research chicken immune organ growth with histology conventional slice technology and immunohistochemistry dye. 1 day age healthy roosters were divided into 3 groups： the group 3 was control group. 1% and 0.5% concentration of Chinese herbal medicine immunopotentiator drinking water were added in the group 1 and 2 in continuous 60 d. The immune organ index was determined every 12 d and the histotomy of chicken small intes- tine in group control and 1% were taken for histological observation on day 24, 36 and 48. [ Result] Treatment group immune organ index was significantly higher than that of the control group and 1% group of small intestinal villus inherent intraformational immune cells number significantly increased （P〈0.01） compared with controls. Day 36 age group and day 48 group immune cells were higher than day 24 group of cell number （P〈 0.01 ）. [ Conclusionl Chinese medicinal herb had obvious role in promoting chicken immune organ growth and obvious influence on the quantity change of the intestinal mucosal immune cells.

The role of probiotics in prevention and treatment of food allergy

With the prevalence of food allergy increasing every year,food allergy has become a common public health problem.More and more studies have shown that probiotics can intervene in food allergy based on the intestinal mucosal immune system.Probiotics and their metabolites can interact with immune cells and gut microbiota to alleviate food allergy.This review outlines the relationship between the intestinal mucosal immune system and food allergy.This review also presents the clinical application and potential immunomodulation mechanisms of probiotics on food allergy.We aim at providing a reference for further studies to explore the key active substances and immunomodulation mechanisms of anti-allergic probiotics.

A randomized double-blind trial on perioperative administration of probiotics in colorectal cancer patients

AIM:To investigate whether probiotic bacteria,given perioperatively,might adhere to the colonic mucosa, reduce concentration of pathogens in stools,and modulate the local immune function. METHODS:A randomized,double-blind clinical trial was carried out in 31 subjects undergoing elective colorectal resection for cancer.Patients were allocated to receive either a placebo(group A,n=10),or a dose of 10 7 of a mixture of Bifidobacterium longum(BB536) and Lactobacillus johnsonii(La1)(group B,n=11),or the same mixture at a concentration of 10 9 (group C,n=10).Probiotics,or a placebo,were given orally 2 doses/d for 3 d before operation.The same treatment continued postoperatively from day two to day four. Stools were collected before treatment,during surgery (day 0)and 5 d after operation.During the operation, colonic mucosa samples were harvested to evaluate bacterial adherence and to assess the phenotype of dendritic cells(DCs)and lymphocyte subsets by surface antigen expression(flow cytometry).The presence of BB536 and La1 was evaluated by the random amplified polymorphism DNA method with specific polymerase chain reaction probes. RESULTS:The three groups were balanced for baseline and surgical parameters.BB536 was never found at any time-points studied.At day 0,La1 was present in 6/10(60%)patients in either stools or by biopsy in group C,in 3/11(27.2%)in group B,and none in the placebo group(P=0.02,C vs A).There was a linear correlation between dose given and number of adher- ent La1(P=0.01).The rate of mucosal colonization by enterobacteriacae was 30%(3/10)in C,81.8%(9/11) in B and 70%(7/10)in A(P=0.03,C vs B).The Enterobacteriacae count in stools was 2.4(log10 scale) in C,4.6 in B,and 4.5 in A(P=0.07,C vs A and B). The same trend was observed for colonizing enterococ- ci.La1 was not found at day+5.We observed greater expression of CD3,CD4,CD8,and naive and memory lymphocyte subsets in group C than in group A with a dose response trend(C>B>A).Treatment didnot affect DC phenotype or activation,but after ex vivo stimulation with lipopolysaccharides,groups C and B had a lower proliferation rate compared to group A (P=0.04).Moreover,dendritic phenotypes CD83-123, CD83-HLADR,and CD83-11c(markers of activation) were significantly less expressed in patients colonized with La1(P=0.03 vs not colonized). CONCLUSION:La1,but not BB536,adheres to the colonic mucosa,and affects intestinal microbiota byreducing the concentration of pathogens and modulates local immunity.

The development and role of microbialhost interactions in gut mucosal immune development

At birth the piglet＇s immune system is immature and it is dependent upon passive maternal protection until weaning.The piglet＇s mucosal immune system develops over the first few weeks but has not reached maturity at weaning ages which are common on commercial farms. At weaning piglets are presented with a vast and diverse range of microbial and dietary/environmental antigens. Their ability to distinguish between antigens and mount a protective response to potential pathogens and to develop tolerance to dietary antigens is critical to their survival and failure to do so is reflected in the high incidence of morbidity and mortality in the post-weaning period. A growing recognition that the widespread use of antibiotics to control infection during this critical period should be controlled has led to detailed studies of those factors which drive the development of the mucosal immune system, the role of gut microbiota in driving this process, the origin of the bacteria that colonise the young piglet＇s intestine and the impact of rearing environment. This review briefly describes how the mucosal immune system is equipped to respond ＂appropriately＂ to antigenic challenge and the programmed sequence by which it develops. The results of studies on the critical interplay between the host immune system and gut microbiota are discussed along with the effects of rearing environment. By comparing these with results from human studies on the development of allergies in children, an approach to promote an earlier maturation of the piglet immune system to resist the challenges of weaning are outlined.

The Development of Early Life Microbiota in Human Health and Disease

The colonization of the human microbiota in early life has long-lasting health implications.The status of the initial intestinal microbiota determines human growth and development from infancy to adulthood,and thus represents a crucial window in our long-term development.This review aims to summarize the latest findings on the symbiotic gut microbiota early in life and its vital role in metabolic-,allergic-,and auto-immune-disorder-related diseases,including obesity,diabetes,allergy,autism,inflammatory bowel disease,and stunting.It discusses the development process and various factors shaping the gut micro-biota,as well as the crosstalk between the gut microbiota and the host’s physiological systems(especially intestinal immune development and homeostasis,and the central nervous system in the course of neu-rodevelopment),during the early life establishment of the gut microbiota,in order to decipher the mech-anisms of diseases associated with the intestinal microbiome of early life.In addition,it examines microbiota-targeted therapeutic methods that show promising effects in treating these diseases.The true process of gut microbiome maturation,which depends on genetics,nutrition,and environmental factors,must be scrutinized in order to monitor healthy gut microbiome development and potentially correct unwanted courses by means of intervention via methods such as novel probiotics or fecal microbiota transplantation.

Spinal anesthesia alleviates dextran sodium sulfate-induced colitis by modulating the gut microbiota

BACKGROUND Inflammatory bowel disease(IBD)is a chronic disease with recurrent intestinal inflammation.Although the exact etiology of IBD remains unknown,the accepted hypothesis of the pathogenesis to date is that abnormal immune responses to the gut microbiota are caused by environmental factors.The role of the gut microbiota,particularly the bidirectional interaction between the brain and gut microbiota,has gradually attracted more attention.AIM To investigate the potential effect of spinal anesthesia on dextran sodium sulfate(DSS)-induced colitis mice and to detect whether alterations in the gut microbiota would be crucial for IBD.METHODS A DSS-induced colitis mice model was established.Spinal anesthesia was administered on colitis mice in combination with the methods of cohousing and fecal microbiota transplantation(FMT)to explore the role of spinal anesthesia in IBD and identify the potential mechanisms involved.RESULTS We demonstrated that spinal anesthesia had protective effects against DSS-induced colitis by alleviating clinical symptoms,including reduced body weight loss,decreased disease activity index score,improved intestinal permeability and colonic morphology,decreased inflammatory response,and enhanced intestinal barrier functions.Moreover,spinal anesthesia significantly increased the abundance of Bacteroidetes,which was suppressed in the gut microbiota of colitis mice.Interestingly,cohousing with spinal anesthetic mice and FMT from spinal anesthetic mice can also alleviate DSS-induced colitis by upregulating the abundance of Bacteroidetes.We further showed that spinal anesthesia can reduce the increase in noradrenaline levels induced by DSS,which might affect the gut microbiota.CONCLUSION These data suggest that microbiota dysbiosis may contribute to IBD and provide evidence supporting the protective effects of spinal anesthesia on IBD by modulating the gut microbiota,which highlights a novel approach for the treatment of IBD.

A comprehensive review on the effects of green tea and its components on the immune function

Green tea and its bioactive components possess many health-promoting and disease-preventing benefits,especially anti-inflammatory,antioxidant,anticancer,and metabolic modulation effects with multi-target modes of action.In contrast,the effects and mechanisms of tea and its components on the immune system are rarely reviewed.The study aimed to review the most potent compounds in tea that affect the immune systems and mechanisms associated with it.As a result of in vitro studies,animal models,and human trials,researchers have found that green tea extracts and compounds have the possibility of modulating the innate immune system,adaptive immune system,and intestinal immune system.In immune-related diseases,tea polyphenols are the most significant compounds that modify immune functions,though other compounds are being investigated and cannot be ruled out.The review provides a new perspective on how the immune-regulatory effects of tea and its components are exerted on immune systems,as well as how they affect the emergence and treatment of diseases.

Self-assembled aggregations in Coptidis Rhizoma decoction dynamically regulate intestinal tissue permeability through Peyer's patch-associated immunity

Objective:To investigate the dynamic regulation of self-assembled aggregations(SAA)in Coptidis Rhizoma decoction on the permeability of intestinal tissue and the mechanism underlying.Methods:The effects of SAA on berberine(Ber)absorption were respectively analyzed in an in situ intestinal perfusion model and in an Ussing Chamber jejunum model with or without Peyer’s patches(PPs).The expression levels of ZO-1,Occludin and Claudin-1 were detected by immunofluorescence to evaluate the tight junction(TJ)between intestinal epithelium cells.The expression levels of T-box-containing protein expressed in T cells,signal transducers and activators of tranion-6,retinoic acid receptor-related orphan receptor ct and forkhead box P3 in PPs were detected by the reverse transcription-polymerase chain reaction and the secretions of interferon-c(IFN-c),interleukin-4(IL-4),interleukin-17(IL-17)and transforming growth factor-b(TGF-b)in PPs were evaluated by immunohistochemistry,to reflect the differentiation of T lymphocyte in PPs to helper T(Th)cell 1,Th2,Th17 and regulatory T(Treg)cell.To confirm the correlation between SAA in Coptidis Rhizoma decoction,PPs-associated immunity and intestinal epithelium permeability,SAA were administrated on an Ussing Chamber jejunum model with immunosuppressed PPs and evaluated its influences on intestinal tissue permeability and TJ proteins expression.Results:SAA in Coptidis Rhizoma decoction could dose-dependently promote Ber absorption in jejunum segment,with the participation of PPs.The dose-dependent and dynamical regulations of SAA on permeability of intestinal tissue and TJ proteins expression level between intestinal epithelium cells occurred along with the dynamically changed T lymphocyte differentiation and immune effectors secretion in PPs.The administration of SAA on immunosuppressed PPs exhibited dose-dependent PPs activation,inducing dynamic promotion on intestinal tissue permeability and inhibition on TJ proteins expression.Conclusion:SAA can improve the Ber absorption in small intestine,through the PPs-associated immunity induced dynamic regulation on intestinal tissue permeability and TJ proteins expression.These findings might enlighten the research of traditional Chinese medicine decoction.

Nutritional stimulation of the autonomic nervous system

Disturbance of the inflammatory response in the gut is important in several clinical diseases ranging from inflmmatory bowel disease to postoperative ileus. Several feedback mechanisms exist that control the inflammatory cascade and avoid collateral damage. In the gast rointestinal tract, it is of particular importance tocontrol the immune response to maintain the balance that allows dietary up take and utilization of nutrientson one hand, while preventing invasion of bacteria and toxins on the other hand. The process of digestion and absorption of nutrients requires a relative hyporesponsiveness of the immune cells in the gut to luminacontents which is not yet fully understood. Recentlythe autonomic nervous system has been identifi ed asan important pathway to control local and systemic inflammation and gut barrier integrity. Activation of thepathway is possible via electrical or via pharm acological interventions, but is also achieved in a physiologicamanner by ingestion of dietary lipids. Administration of dietary lipids has been shown to be very effectivein reducing the inflammatory cascade and maintaining intestinal barrier integrity in several experimental studies. This beneficial effect of nutrition on the inflammatory response and intestinal barrier integrity opens new therapeutic opportunities for treatment of certain gastrointestinal disorders. Furthermore, this neural feedback mechanism provides more insight in the relative hyporesponsiveness of the immune cells in the gut. Here, we will discuss the regulatory function of the autonomic nervous system on the inflammatory response and gut barrier function and the potential benefit in a clinical setting.

Review:Do Horses Receive Optimum Amounts of Glutamine in Their Diets?

In some species of growing mammals glutamine is an essential amino acid that,if inadequate in the diet,is needed for normal growth and development.It is thus sometimes considered to be a conditionally essential amino acid in some species.A review of studies that have measured L-glutamine concentrations([glutamine])in horses demonstrates that plasma[glutamine]has routinely been reported to be much lower(~330μmol/L)than in other mammals(>600μmol/L).Plasma[glutamine]represents the balance between intestinal transport into the blood after hepatic first pass,tissue synthesis and cellular extraction.The hypothesis is proposed that sustained low plasma[glutamine]represents a chronic state of sub-optimal glutamine intake and glutamine synthesis that does not meet the requirements for optimum health.While this may be without serious consequence in feral and sedentary horses,there is evidence that provision of supplemental dietary glutamine ameliorates a number of health consequences,particularly in horses with elevated metabolic demands.The present review provides evidence that glutamine is very important(and perhaps essential)for intestinal epithelial cells in mammals including horses,that horses with low plasma[glutamine]represents a sub-optimal state of well-being,and that horses supplemented with glutamine exhibit physiological and health benefits.

ILC3-derived OX40L is essential for homeostasis of intestinal Tregs in immunodeficient mice

OX40L is one of the co-stimulatory molecules that can be expressed by splenic lymphoid tissue inducer(Lti)cells,a subset of group 3 innate lymphoid cells(ILC3s).OX40L expression in subsets of intestinal ILC3s and the molecular regulation of OX40L expression in ILC3s are unknown.Here,we showed intestinal ILC3s marked as an OX40L high population among all the intestinal leukocytes and were the dominant source of OX40L in Rag1–/–mice.All ILC3 subsets expressed OX40L,and NCR–ILC3s were the most abundant source of OX40L.The expression of OX40L in ILC3s could be upregulated during inflammation.In addition to tumor necrosis factor(TNF)-like cytokine 1A(TL1A),which has been known as a trigger for OX40L,we found that Poly(I:C)representing viral stimulus promoted OX40L expression in ILC3s via a cell-autonomous manner.Furthermore,we demonstrated that IL-7-STAT5 signaling sustained OX40L expression by ILC3s.Intestinal regulatory T cells(Tregs),most of which expressed OX40,had defective expansion in chimeric mice,in which ILC3s were specifically deficient for OX40L expression.Consistently,co-localization of Tregs and ILC3s was found in the cryptopatches of the intestine,which suggests the close interaction between ILC3s and Tregs.Our study has unveiled the crosstalk between Tregs and ILC3s in mucosal tissues through OX40–OX40L signaling,which is crucial for the homeostasis of intestinal Tregs.

Evaluation of the Mechanisms Underlying Amino Acid and Microbiota Interactions in Intestinal Infections Using Germ-Free Animals

Intestinal infectious diseases refer to the inflammatory changes in the intestinal tract caused by pathogens(including bacteria,viruses,fungi,protozoa,or parasites)or their toxic products.A large number of microorganisms colonize the intestinal tract of healthy people,which together with the intestinal epithelium constitute the biological barrier of the intestinal tract to resist infectious diseases.As an“invisible organ,”the intestinal flora is closely related to human nutrition metabolism and intestinal infections.A variety of intestinal flora participates in the nutritional metabolism of amino acids,and the small molecular substances produced by the amino acid metabolism through the intestinal flora can enhance intestinal immunity and resist bacterial infections.In turn,amino acids can also regulate the composition of the intestinal flora,maintain the steady-state of the intestinal flora,protect the intestinal barrier,and inhibit colonization by pathogenic bacteria.As a model animal with a clear microbial background,germ-free(GF)animals can clarify the mechanisms of interactions between intestinal microbes and amino acid metabolism in intestinal infections by combining genetic engineering technology and multi-omics studies.This article reviews related researches on the involvement of intestinal microbes in host amino acid metabolism and resistance to intestinal infections and discusses the advantages of GF animal models for studying the underlying mechanisms.The GF animal model is helpful to further study the intervention effects of amino acid metabolism of targeted intestinal flora on intestinal infections.

Intestinal immune barrier integrity in rats with nonalcoholic hepatic steatosis and steatohepatitis

Background Nonalcoholic fatty liver disease （NAFLD） has emerged as the major cause of chronic liver injury.Intestinal barrier plays an important role in the pathogenis of NAFLD.The aim of this article was to assess intestinal immune barrier function during the development of NAFLD.Methods Totally 60 male Sprague-Dawley （SD） rats were divided into 2 groups：normal diet （ND） group and high-fat diet （HFD） group.NAFLD rat model was established in the HFD rat group.Portal blood endotoxin level was assessed by limulus test.The percentage of CD4＋ cells and CD8＋ cells in peripheral blood mononuclear cells （PBMC） and lymphocytes in Peyer＇s patches （PP） were analysed by flow cytometry.Intestinal secretory immunoglobulin A （SIgA） level was evaluated by enzyme-linked immunosorbent assay.Paired Student＇s t test was used for the statistic analysis.Results HFD rats presented with simple steatosis at the 4th and 8th week and progressed to nonalcoholic steatohepatitis at the 12th week.Elevated lipopolysaccharides （LPS） level in HFD rats was observed at the 8th week （（1.54±0.30） times of ND group,P 〈0.01）.CD4/CD8 ratios in PBMC and PP of HFD rats were increased at the 4th week （（1.50±0.47） and （1.63±0.34） times of ND group,P 〈0.05） and decreased at the 8th week （（0.50±0.16） and （0.61±0.26）times of ND group,P 〈0.05）.At the 12th week,CD4/CD8 ratio （（1.47±0.46） times,P 〈0.05） in PP increased to levels observed in the 4th week.Intestinal SIgA expression of HFD rats was remarkably up-regulated at 12th week （（2.70±1.65）times,P 〈0.05）.Conclusion Liver-gut axis in rats with NAFLD may mediate and improve intestinal immune function by increased CD4/CD8 ratio in PP and increased production of SIgA.

Berberine might block colorectal carcinogenesis by inhibiting the regulation of B-cell function by Veillonella parvula

Background:Colorectal carcinogenesis and progression are related to the gut microbiota and the tumor immune microenvironment.Our previous clinical trial demonstrated that berberine(BBR)hydrochloride might reduce the recurrence and canceration of colorectal adenoma(CRA).The present study aimed to further explore the mechanism of BBR in preventing colorectal cancer(CRC).Methods:We performed metagenomics sequencing on fecal specimens obtained from the BBR intervention trial,and the differential bacteria before and after medication were validated using quantitative polymerase chain reaction.We further performed Apc Min/+animal intervention tests,RNA sequencing,flow cytometry,immunohistochemistry,and enzyme-linked immunosorbent assays.Results:The abundance of fecal Veillonella parvula(V.parvula)decreased significantly after BBR administration(P=0.0016)and increased through the development from CRA to CRC.Patients with CRC with a higher V.parvula abundance had worse tumor staging and a higher lymph node metastasis rate.The intestinal immune pathway of Immunoglobulin A production was activated,and the expression of TNFSF13B(Tumor necrosis factor superfamily 13b,encoding B lymphocyte stimulator[BLyS]),the representative gene of this pathway,and the genes encoding its receptors(interleukin-10 and transforming growth factor beta)were significantly upregulated.Animal experiments revealed that V.parvula promoted colorectal carcinogenesis and increased BLyS levels,while BBR reversed this effect.Conclusion:BBR might inhibit V.parvula and further weaken the immunomodulatory effect of B cells induced by V.parvula,thereby blocking the development of colorectal tumors.Trial Registraion:ClinicalTrials.gov,No.NCT02226185.