Efficacy profiles for different concentrations of Lactobacillus acidophilus in experimental colitis

Efficacy of High-Dose Synbiotic Additives for Deoxynivalenol Detoxification: Effects on Blood Biochemistry, Histology, and Intestinal Microbiome in Weaned Piglets

Deoxynivalenol (DON) is a common mycotoxin observed in cereal grains, and feed contamination poses health risks to pigs. Biological antidotes, such as synbiotics (SYNs), have garnered attention for mitigating DON toxicity. This study aimed to assess the efficacy of SYNs by comparing the blood biochemistry, histology, and gut microbiome of weaned piglets. A 4-week trial was conducted on 32 weaned piglets. After a week of diet and environmental adaptation, the pigs were divided into four groups: (1) control (CON, n = 8); (2) SYN (n = 8); (3) DON (n = 8); and (4) DON+SYN (n = 8). The SYN supplementation of weaned piglets increased the final body weight (21.71 ± 0.93 vs. 20.73 ± 0.84), average daily gain (0.38 ± 0.02 vs. 0.34 ± 0.02), and gain-to-feed ratio (0.49 ± 0.04 vs. 0.43 ± 0.02), and decreased the feed conversion ratio (2.14 ± 0.14 vs. 2.39 ± 0.13) compared to the DON group. A high dose of DON induced liver and colon fibrosis and liver and cecum apoptosis, which were alleviated by SYNs. Glucose in the DON group (84.9 ± 3.7) was significantly lower than in the control (101.3 ± 4.2). Additionally, both the DON and DON+SYN groups exhibited higher creatine (0.9 ± 0.0 and 0.9 ± 0.1) and lower cholesterol (88.3 ± 3.2 and 90.0 ± 4.8) levels (p < 0.05). In conclusion, SYNs alleviated DON toxicity, indicating its potential as an antidote for specific biomarkers.

Gut instinct: harnessing the power of probiotics to tame pathogenic signaling pathways in ulcerative colitis

Ulcerative colitis (UC) is a chronic inflammatory bowel disease (IBD) marked by persistent inflammation of the mucosal lining of the large intestine, leading to debilitating symptoms and reduced quality of life. Emerging evidence suggests that an imbalance of the gut microbiota plays a crucial role in UC pathogenesis, and various signaling pathways are implicated in the dysregulated immune response. Probiotics are live microorganisms that confer health benefits to the host, have attracted significant attention for their potential to restore gut microbial balance and ameliorate inflammation in UC. Recent studies have elucidated the mechanisms by which probiotics modulate these signaling pathways, often by producing anti-inflammatory molecules and promoting regulatory immune cell function. For example, probiotics can inhibit the nuclear factor-κB (NF-κB) pathway by stabilizing Inhibitor of kappa B alpha (IκBα), dampening the production of proinflammatory cytokines. Similarly, probiotics can modulate the Janus kinase/signal transducer and activator of transcription (JAK/STAT) signaling pathway, suppressing the activation of STAT1 and STAT3 and thus reducing the inflammatory response. A better understanding of the underlying mechanisms of probiotics in modulating pathogenic signaling pathways in UC will pave the way for developing more effective probiotic-based therapies. In this review, we explore the mechanistic role of probiotics in the attenuation of pathogenic signaling pathways, including NF-κB, JAK/STAT, mitogen-activated protein kinases (MAPKs), Wnt/β-catenin, the nucleotide-binding domain (NOD)-, leucine-rich repeat (LRR)- and pyrin domain-containing protein 3 (NLRP3) inflammasome, Toll-like receptors (TLRs), interleukin-23 (IL-23)/IL-17 signaling pathway in UC.

Preclinical evidence of probiotics in ulcerative colitis: a systematic review and network meta-analysis

The imbalance of gastrointestinal microbial composition has been identified as the main factor of chronic inflammatory diseases. At present, probiotics have a beneficial effect on the microbial composition of the human gastrointestinal tract, but it is still controversial and the specific mechanism is unknown. The purpose of this network meta-analysis is to compare the mechanism of different probiotics on ulcerative colitis. PubMed, Embase, and Web of Science were searched till 16 November 2022. The SYRCLE risk bias assessment tool was used to assess the quality of the research studies. A total of 42 studies, 839 ulcerative colitis models, and 24 kinds of probiotics were finally included. The results showed that L. rhamnosus has the best effect in relieving weight loss and improving the Shannon index in the ulcerative colitis model. E. faecium has the best effect in reducing colon injury; L. reuteri has the best effect in reducing the DAI; L. acidophilus has the best effect in reducing the HIS index and increasing the expression of tight junction protein ZO-1; and L. coryniformis has the best effect in reducing the content of serum pro-inflammatory factor TNF-α. It indicated that probiotics can improve ulcerative colitis by improving histopathological manifestations, reducing inflammatory reaction, and repairing the mucosal barrier, and different probiotics showed different effects. However, considering the limitations of this study, preclinical studies that require more large samples and high-quality and more reliable and rigorous experimental designs and reports need to be conducted in the future. Systematic Review Registration: https://www.crd.york.ac.uk/prospero/#record details, identifier CRD42022383383.

Lactobacillus acidophilus regulates abnormal serotonin availability in experimental ulcerative colitis

OBJECTIVES

Probiotics are known to play a beneficial role in curing irritable bowel syndrome such as ulcerative colitis. Commensal Lactobacillus species are thought to play a protective role against ulcerative colitis, as they restore homeostasis in intestinal disorders. Abnormal serotonin availability has been described in ulcerative colitis, but the underlying mechanism is still unclear. The aim of this study was to determine the anti-inflammatory role of Lactobacillus acidophilus (L. acidophilus) and its effect on serotonin expression.

METHODS

Ulcerative colitis was created with the intrarectal administration of acetic acid. A total of 40 adult male rats were divided into five groups of eight rats as control, sham, experimental colitis, treatment (Colitis + L. acidophilus) and protective group (L. acidophilus + colitis). To evaluate the effects of L. acidophilus on serotonin expression in ulcerative colitis, this bacterial strain was administered orally to the rats with acetic acid-induced colitis. After oral administration of L. acidophilus for 14 days, serotonin content was biochemically measured and serotonin expression was evaluated immunohistochemically.

RESULTS

The expression of serotonin and its protein content was significantly increased in colitis compared to the control and sham groups. Abnormal serotonin availability in the rats with acetic acid-induced colitis was significantly reduced by the L. acidophilus.

CONCLUSIONS

In our study, it was observed that the amount of serotonin in the intestinal tissue increased excessively with ulcerative colitis. In addition, L.acidophilus has been found to reduce the abnormally increased amount of serotonin in the colon tissue, as well as reduce the inflammation in the intestinal tissue that occurs with ulcerative colitis. With our findings, it is predicted that probiotic application can be used as a treatment option in ulcerative colitis.

Bin1 targeted immunotherapy alters the status of the enteric neurons and the microbiome during ulcerative colitis treatment

Ulcerative colitis (UC) is a common chronic disease of the large intestine. Current anti-inflammatory drugs prescribed to treat this disease have limited utility due to significant side-effects. Thus, immunotherapies for UC treatment are still sought. In the DSS mouse model of UC, we recently demonstrated that systemic administration of the Bin1 monoclonal antibody 99D (Bin1 mAb) developed in our laboratory was sufficient to reinforce intestinal barrier function and preserve an intact colonic mucosa, compared to control subjects which displayed severe mucosal lesions, high-level neutrophil and lymphocyte infiltration of mucosal and submucosal areas, and loss of crypts. A dysbiotic microbiome may lead to UC. We determined the effects of Bin1 mAb on the gut microbiome and colonic neurons and correlated the benefits of immunotherapeutic treatment. In the DSS model, we found that induction of UC was associated with disintegration of enteric neurons and elevated levels of glial cells, which translocated to the muscularis at distinct sites. Further, we characterized an altered gut microbiome in DSS treated mice associated with pathogenic proinflammatory characters. Both of these features of UC induction were normalized by Bin1 mAb treatment. With regard to microbiome changes, we observed in particular, increase in Enterobacteriaceae; whereas Firmicutes were eliminated by UC induction and Bin1 mAb treatment restored this phylum including the genus Lactobacillus. Overall, our findings suggest that the intestinal barrier function restored by Bin1 immunotherapy in the DSS model of UC is associated with an improvement in the gut microbiome and preservation of enteric neurons, contributing overall to a healthy intestinal tract.

Oral supplementation with selected Lactobacillus acidophilus triggers IL-17-dependent innate defense response, activation of innate lymphoid cells type 3 and improves colitis

Live biotherapeutic products constitute an emerging therapeutic approach to prevent or treat inflammatory bowel diseases. Lactobacillus acidophilus is a constituent of the human microbiota with probiotic potential, that is illustrated by improvement of intestinal inflammation and antimicrobial activity against several pathogens. In this study, we evaluated the immunomodulatory properties of the L. acidophilus strain BIO5768 at steady state and upon acute inflammation. Supplementation of naïve mice with BIO5768 heightened the transcript level of some IL-17 target genes encoding for protein with microbicidal activity independently of NOD2 signaling. Of these, the BIO5768-induced expression of Angiogenin-4 was blunted in monocolonized mice that are deficient for the receptor of IL-17 (but not for NOD2). Interestingly, priming of bone marrow derived dendritic cells by BIO5768 enhanced their ability to support the secretion of IL-17 by CD4⁺ T cells. Equally of importance, the production of IL-22 by type 3 innate lymphoid cells is concomitantly heightened in response to BIO5768. When administered alone or in combination with Bifidobacterium animalis spp. lactis BIO5764 and Limosilactobacillus reuteri, BIO5768 was able to alleviate at least partially intestinal inflammation induced by Citrobacter rodentium infection. Furthermore, BIO5768 was also able to improve colitis induced by 2,4,6-trinitrobenzene sulfonic acid (TNBS). In conclusion, we identify a new potential probiotic strain for the management of inflammatory bowel diseases, and provide some insights into its IL-17-dependent and independent mode of action.

n-6 High Fat Diet Induces Gut Microbiome Dysbiosis and Colonic Inflammation

Background: Concerns are emerging that a high-fat diet rich in n-6 PUFA (n-6HFD) may alter gut microbiome and increase the risk of intestinal disorders. Research is needed to model the relationships between consumption of an n-6HFD starting at weaning and development of gut dysbiosis and colonic inflammation in adulthood. We used a C57BL/6J mouse model to compare the effects of exposure to a typical American Western diet (WD) providing 58.4%, 27.8%, and 13.7% energy (%E) from carbohydrates, fat, and protein, respectively, with those of an isocaloric and isoproteic soybean oil-rich n-6HFD providing 50%E and 35.9%E from total fat and carbohydrates, respectively on gut inflammation and microbiome profile. Methods: At weaning, male offspring were assigned to either the WD or n-6HFD through 10-16 weeks of age. The WD included fat exclusively from palm oil whereas the n-6HFD contained fat exclusively from soybean oil. We recorded changes in body weight, cyclooxygenase-2 (COX-2) expression, colon histopathology, and gut microbiome profile. Results: Compared to the WD, the n-6HFD increased plasma levels of n-6 fatty acids; colonic expression of COX-2; and the number of colonic inflammatory and hyperplastic lesions. At 16 weeks of age, the n-6HFD caused a marked reduction in the gut presence of Firmicutes, Clostridia, and Lachnospiraceae, and induced growth of Bacteroidetes and Deferribacteraceae. At the species level, the n-6HFD sustains the gut growth of proinflammatory Mucispirillum schaedleri and Lactobacillus murinus. Conclusions: An n-6HFD consumed from weaning to adulthood induces a shift in gut bacterial profile associated with colonic inflammation.

Dose-dependent effects of kefir on colitis induced by trinitrobenzene sulfonic acid in rats

Evidence suggests that gut microbiota dysbiosis plays a critical role in the initiation and promotion of inflammatory bowel disease (IBD). Kefir is a fermented dairy product including yeast and bacterial species. We aimed to investigate the effect of kefir on trinitrobenzene sulfonic acid (TNBS)-induced colitis in rats using two different doses. Fifty-four Wistar rats were divided into six groups. For 14 days, the normal control and colitis control groups were given tap water, kefir10 control, kefir10 colitis, and kefir30 control, and the kefir30 colitis groups were given phosphate-buffered saline containing 10% or 30% kefir, respectively, instead of tap water. Colitis was induced by intracolonically administrating TNBS in the colitis control, kefir10 colitis, and kefir30 colitis groups. On the 14th day, the rats were sacrificed. The weights and lengths of the colons were measured and macroscopically evaluated, and the distal 10 cm segments were subjected to a histopathological examination. The incidence of bloody stool and diarrhea in the kefir10 colitis group was found to be less than the colitis control and kefir30 colitis groups. The colonic weight/length ratio in the kefir10 colitis group was lower than that in the colitis control and kefir30 colitis groups. We detected that the 10% kefir treatment reduced TNBS-induced macroscopic colonic damage, while it was exacerbated by the 30% kefir treatment. No significant difference was observed between the colitis groups in terms of microscopic colonic damage scoring. These results indicate that kefir, with a careful dose selection, may be a useful agent in the treatment of IBD.

The Probiotic, ID-JPL934, Attenuates Dextran Sulfate Sodium-Induced Colitis in Mice Through Inhibition of Proinflammatory Cytokines Expression

Despite the increasing prevalence of inflammatory bowel disease (IBD), classified as immune-mediated disorders, the exact biological mechanisms leading to its development are undetermined, and treatment strategies remain elusive. Probiotics have been proposed as potential alternatives for treating IBD. The purpose of this research was to find therapeutic candidates of probiotics for colitis. We adopted dextran sulfate sodium (DSS)-induced colitis model to demonstrate the therapeutic effects of ID-JPL934, a mixture of three live bacterial strains at a 1:1:1 ratio: Lactobacillus johnsonii IDCC9203, Lactobacillus plantarum IDCC3501, and Bifidobacterium animalis subspecies lactis IDCC4301, on IBD. The severity was scored according to the disease activity index (DAI) for colitis by observing body weight (BW) and stool status of each mouse once a day. BALB/c mice given 3.5% DSS in drinking water suffered from symptoms of colitis such as weight loss, diarrhea, and bloody excrement. In our study, administration of ID-JPL934 reduced the DAI scores in a dose-dependent manner, and treatments with ID-JPL934 10⁸ and 10⁹ colony-forming unit per mouse per day showed similar inhibition compared with those of sulfasalazine 500 mg per kg BW per day. Moreover, the contraction of colon length improved. ID-JPL934 also suppressed inflammatory lesions such as infiltration of immune cells in mucosa and submucosa, severe crypt damage, and loss of goblet and epithelial cells on the histological analysis. These results might be due to downregulation of the expression of proinflammatory cytokines, including tumor necrosis factor-α, interleukin (IL)-1β, and IL-6. From these results, ID-JPL934 might be an effective therapeutic candidate for IBD.

Probiotic Species in the Modulation of Gut Microbiota: An Overview

Probiotics are microbial strains that are beneficial to health, and their potential has recently led to a significant increase in research interest in their use to modulate the gut microbiota. The animal gut is a complex ecosystem of host cells, microbiota, and available nutrients, and the microbiota prevents several degenerative diseases in humans and animals via immunomodulation. The gut microbiota and its influence on human nutrition, metabolism, physiology, and immunity are addressed, and several probiotic species and strains are discussed to improve the understanding of modulation of gut microbiota. This paper provides a broad review of several Lactobacillus spp., Bifidobacterium spp., and other coliform bacteria as the most promising probiotic species and their role in the prevention of degenerative diseases, such as obesity, diabetes, cancer, cardiovascular diseases, malignancy, liver disease, and inflammatory bowel disease. This review also discusses a recent study of Saccharomyces spp. in which inflammation was prevented by promotion of proinflammatory immune function via the production of short-chain fatty acids. A summary of gut microbiota alteration with future perspectives is also provided.

IL-8 antagonist, CXCL8(3-72)K11R/G31P coupled with probiotic exhibit variably enhanced therapeutic potential in ameliorating ulcerative colitis

Inflammatory bowel disease (IBD) remains a major health challenge due in part to unsafe and limited treatment options, hence there is the need for alternatives. CXCL8/interleukin 8 (IL-8) is elevated in inflammation, and binds preferentially to G protein-couple receptors (GPCRs) CXCR1/2 of the CXC chemokine family to initiate cascades of downstream inflammatory signals. A mutant CXCL8 protein, CXCL8(3-72)K11R/G31P (G31P), competitively and selectively binds to CXCR1/2, making CXCL8 redundant. We explore the therapeutic potential of G31P in dextran sulfate sodium (DSS) induced ulcerative colitis (UC), and the corresponding effect if G31P treatment is augmented with Lactobacillus acidophilus (LACT). The treatment options administered significantly reduced TNF-α, IFN-γ, IL-1β, IL-6, and IL-8, but maintained elevated levels of IL-10. CD68 and F4/80 expressions were down-regulated and showed restricted infiltration to inflamed colon, while IL-17F levels were insignificantly different from the DSS treated mice. Also, we observed up-regulation of IL-17A in G31P + LACT but not G31P treated mice if compared with Control group. The treatments ameliorated colonic fibrosis by reducing VEGF, TGF-β, MMP-2 and MMP-9. In addition, we observed elevated levels of E-cadherin, and marginal up-regulation of occludin, suggesting the role of the treatments in regulating tight intestinal junction and adherence proteins. Mechanism-wise, G31P interferes with AKT and ERK signaling pathways. Our study suggests that G31P confers protection in IBD, particularly UC, and when G31P treatment is augmented with Lactobacillus acidophilus, the protection is variably enhanced.

Probiotics: The scientific evidence in the context of inflammatory bowel disease

Inflammatory bowel disease (IBD) generally comprises Crohn's disease (CD) and ulcerative colitis (UC), and their main characteristic is the intestinal mucosa inflammation. Although its origin is not yet fully known, there is growing evidence related to genetics, intestinal microbiota composition, and the immune system factors such as precursors for the initiation and progression of intestinal conditions. The use of certain probiotic microorganisms has been touted as a possible and promising therapeutic approach in reducing the risk of inflammatory bowel disease, specifically ulcerative colitis. Several mechanisms have been proposed to explain the benefits of probiotics, indicating that some bacterial strains are able to positively modulate the intestinal microbiota and the immune system, and to produce metabolites with anti-inflammatory properties. The aim of this paper is to bring together the various results and information, based on scientific evidence, that are related to probiotics and inflammatory bowel disease, emphasizing the possible mechanisms involved in this action.

Different Effects of Three Selected Lactobacillus Strains in Dextran Sulfate Sodium-Induced Colitis in BALB/c Mice

AIM

To analyze the changes of different Lactobacillus species in ulcerative colitis patients and to further assess the therapeutic effects of selected Lactobacillus strains on dextran sulfate sodium (DSS)-induced experimental colitis in BALB/c mice.

METHODS

Forty-five active ulcerative colitis (UC) patients and 45 population-based healthy controls were enrolled. Polymerase chain reaction (PCR) amplification and real-time PCR were performed for qualitative and quantitative analyses, respectively, of the Lactobacillus species in UC patients. Three Lactobacillus strains from three species were selected to assess the therapeutic effects on experimental colitis. Sixty 8-week-old BALB/c mice were divided into six groups. The five groups that had received DSS were administered normal saline, mesalazine, L. fermentum CCTCC M206110 strain, L. crispatus CCTCC M206119 strain, or L. plantarum NCIMB8826 strain. We assessed the severity of colitis based on disease activity index (DAI), body weight loss, colon length, and histologic damage.

RESULTS

The detection rate of four of the 11 Lactobacillus species decreased significantly (P < 0.05), and the detection rate of two of the 11 Lactobacillus species increased significantly (P < 0.05) in UC patients. Relative quantitative analysis revealed that eight Lactobacillus species declined significantly in UC patients (P < 0.05), while three Lactobacillus species increased significantly (P < 0.05). The CCTCC M206110 treatment group had less weight loss and colon length shortening, lower DAI scores, and lower histologic scores (P < 0.05), while the CCTCC M206119 treatment group had greater weight loss and colon length shortening, higher histologic scores, and more severe inflammatory infiltration (P < 0.05). NCIMB8826 improved weight loss and colon length shortening (P < 0.05) with no significant influence on DAI and histologic damage in the colitis model.

CONCLUSIONS

Administration of an L. crispatus CCTCC M206119 supplement aggravated DSS-induced colitis. L. fermentum CCTCC M206110 proved to be effective at attenuating DSS-induced colitis. The potential probiotic effect of L. plantarum NCIMB8826 on UC has yet to be assessed.

Effect of probiotic mixture containing bifidobacteria on dextran sulfate sodium-induced colitis and expression of tight junction protein junctional adhesion molecule-1 in mice

AIM: To investigate whether supplementation with a probiotic mixture (bifidobacterium, lactobacillus and enterococcus) could ameliorate dextran sulfate sodium (DSS)-induced murine colitis and affect the expression and distribution of the tight junction protein junctional adhesion molecule-1 (JAM-1) in colonic tissue.

METHODS: Female Balb/c mice (8-10 wk old) of specific pathogen free grade were randomly divided into five groups: an NC group (normal controls), a BB group (mice administered with the probiotic mixture by intragastric gavage for 14 d), a DSS group (14-day intragastric saline administration + 7-day 4% DSS exposure from day 8), a BD group (7-day intragastric administration of probiotic mixture +7-day 4% DSS exposure from day 8) and a BDB group (14-day intragastric administration of probiotic mixture +7-day 4% DSS exposure from day 8). Body weight was monitored daily. All mice were sacrificed on day 15 and colonic tissue samples were obtained. Colon inflammatory injury in each group was observed and histopathological scores were evaluated. The expression and distribution of JAM-1 in colonic tissues were detected by Western blot and immunohistochemistry, respectively.

RESULTS: Compared with the DSS group, body weight significantly improved in mice administrated with the probiotic mixture by intragastric gavage (95.17% ± 3.34%, 87.17% ± 1.83% vs 81.49 % ± 2.16%, P₁ < 0.01, P₂ = 0.08, for the BD and BDB groups, respectively). Moreover, the probiotic mixture could ameliorate inflamed colon shortening and mucosal edema, as well as alleviate destruction of epithelial cells and the infiltration of inflammatory cells. In addition, the efficacy of the probiotic mixture in the BD group was superior to that in the BDB group. Western blot analysis showed that the level of JAM-1 increased significantly in the colons of mice in the BD and BDB groups compared with that in DSS mice (0.725 ± 0.027, 0.739 ± 0.033 vs 0.454 ± 0.073, P < 0.05 for both). Data from immunohistochemical analysis showed that the positive staining intensity and the number of positively stained cell in the colon of the DSS group were markedly downregulated, and the distribution of JAM-1 was disordered and discontinuous. This phenomenon was improved after administration of the probiotic mixture in mice with DSS-induced colitis. Compared with the normal group, mice administrated with the probiotic mixture alone showed no significant changes in body weight, macroscopic and microscopic manifestation, or the level of JAM-1 in their colonic tissue (P > 0.05).

CONCLUSION: Triple viable probiotic mix containing Bifidobacteria can ameliorate DSS-induced colitis. This may result from improved mucosal barrier function by influencing the expression and distribution of JAM-1.

Protective effect of TSLP delivered at the gut mucosa level by recombinant lactic acid bacteria in DSS-induced colitis mouse model

BACKGROUND

Thymic stromal lymphopoietin (TSLP) is a cytokine known to mature dendritics cells, lower pro-inflammatory IL-12 secretion, induce differentiation of anti-inflammatory FoxP3+ regulatory T cells (Treg). Moreover, Crohn's disease patients have shown a reduction of intestinal TSLP expression. To understand the role of TSLP in inflammation, we constructed Lactococcus lactis strain producing TSLP (LL-TSLP) and investigated the effect of its administration on dextran sulfate sodium (DSS)-induced colitis model in mice.

RESULTS

LL-TSLP secrete an active molecule which lowers secretion of IL-12 by dendritic cells. Treatment with LL-TSLP, increases the amount of TGF-β secreted by T cells in Mesenteric Lymph Node in healthy mice. In acute DSS-induced colitis, LL-TSLP delayed the Disease Activity Index and lowered histological score and colonic INF-γ production. In a DSS-recovery model, LL-TSLP induced a better protective effect if the strain was administered at the beginning of the colitis. At Day 4 of colitis we observed an induction of Treg by LL-TSLP.

CONCLUSIONS

TSLP showed an anti-inflammatory protective role in DSS-induced colitis. We have demonstrated that a short and early administration of LL-TSLP is more efficient than a long lasting treatment.

Manipulation of the Gut Microbiota Reveals Role in Colon Tumorigenesis

Mounting evidence indicates that alterations to the gut microbiota, the complex community of bacteria that inhabits the gastrointestinal tract, are strongly associated with the development of colorectal cancer. We used antibiotic perturbations to a murine model of inflammation-driven colon cancer to generate eight starting communities that resulted in various severities of tumorigenesis. Furthermore, we were able to quantitatively predict the final number of tumors on the basis of the initial composition of the gut microbiota. These results further bolster the evidence that the gut microbiota is involved in mediating the development of colorectal cancer. As a final proof of principle, we showed that perturbing the gut microbiota in the midst of tumorigenesis could halt the formation of additional tumors. Together, alteration of the gut microbiota may be a useful therapeutic approach to preventing and altering the trajectory of colorectal cancer.

There is growing evidence that individuals with colonic adenomas and carcinomas harbor a distinct microbiota. Alterations to the gut microbiota may allow the outgrowth of bacterial populations that induce genomic mutations or exacerbate tumor-promoting inflammation. In addition, it is likely that the loss of key bacterial populations may result in the loss of protective functions that are normally provided by the microbiota. We explored the role of the gut microbiota in colon tumorigenesis by using an inflammation-based murine model. We observed that perturbing the microbiota with different combinations of antibiotics reduced the number of tumors at the end of the model. Using the random forest machine learning algorithm, we successfully modeled the number of tumors that developed over the course of the model on the basis of the initial composition of the microbiota. The timing of antibiotic treatment was an important determinant of tumor outcome, as colon tumorigenesis was arrested by the use of antibiotics during the early inflammation period of the murine model. Together, these results indicate that it is possible to predict colon tumorigenesis on the basis of the composition of the microbiota and that altering the gut microbiota can alter the course of tumorigenesis.

IMPORTANCE Mounting evidence indicates that alterations to the gut microbiota, the complex community of bacteria that inhabits the gastrointestinal tract, are strongly associated with the development of colorectal cancer. We used antibiotic perturbations to a murine model of inflammation-driven colon cancer to generate eight starting communities that resulted in various severities of tumorigenesis. Furthermore, we were able to quantitatively predict the final number of tumors on the basis of the initial composition of the gut microbiota. These results further bolster the evidence that the gut microbiota is involved in mediating the development of colorectal cancer. As a final proof of principle, we showed that perturbing the gut microbiota in the midst of tumorigenesis could halt the formation of additional tumors. Together, alteration of the gut microbiota may be a useful therapeutic approach to preventing and altering the trajectory of colorectal cancer.

Th17 Cells as Potential Probiotic Therapeutic Targets in Inflammatory Bowel Diseases

Inflammatory bowel diseases (IBD) are characterized by wasting and chronic intestinal inflammation triggered by various cytokine-mediated pathways. In recent years, it was shown that T helper 17 (Th17) cells are involved in the pathogenesis of IBD, which makes them an attractive therapeutic target. Th17 cells preferentially produce interleukin (IL)-17A–F as signature cytokines. The role of the interplay between host genetics and intestinal microbiota in the pathogenesis of IBD was demonstrated. Probiotics are live microorganisms that when orally ingested in adequate amounts, confer a health benefit to the host by modulating the enteric flora or by stimulating the local immune system. Several studies indicated the effectiveness of probiotics in preventing and treating IBD (ulcerative colitis, and Crohn’s disease). Furthermore, there is mounting evidence of probiotics selectively targeting the Th17 lineage in the prevention and management of inflammatory and autoimmune diseases such as IBD. This review highlights critical roles of Th17 cells in the pathogenesis of IBD and the rationale for using probiotics as a novel therapeutic approach for IBD through manipulation of Th17 cells. The potential molecular mechanisms by which probiotics modulate Th17 cells differentiation and production are also discussed.

Lactobacillus acidophilus suppresses colitis-associated activation of the IL-23/Th17 axis

The aim of this paper is to determine the modulatory effects of Lactobacillus acidophilus on the IL-23/Th17 immune axis in experimental colitis. DSS-induced mouse models of UC were to be saline, hormones, and different concentrations of Lactobacillus acidophilus intervention. The expression of interleukin- (IL-) 17, tumor necrosis factor α (TNFα), IL-23, transforming growth factor β1 (TGFβ1), signal transducer and activator of transcription 3 (STAT3), and phosphorylated (p)-STAT3 was examined by RT-PCR, Western blotting, and immunohistochemical analysis. And the results showed that administration of L. acidophilus suppressed Th17 cell-mediated secretion of proinflammatory cytokine IL-17 through downregulation of IL-23 and TGFβ1 expression and downstream phosphorylation of p-STAT3.