Inflammatory Diseases of the Gut

The profile of the key pro-inflammatory cytokines in the serum of patients with CD and their association with the disease severity and activity

BACKGROUND

The epidemiology of Crohn's disease (CD) has changed over the past decades, demonstrating a trend toward increased prevalence in developing countries, while in developed countries, its incidence has stabilized. The study aimed to examine the profile of the key pro-inflammatory cytokines in the serum of patients with CD and establish their association with the severity and activity of the disease.

METHODS

A total of 61 patients (29 women (47.5%), 32 men (52.5%) aged from 18 to 40 years (mean age (30.42 ± 2.51) years) with the verified diagnosis of CD in the active phase were examined. The control group consisted of 30 healthy people of corresponding age.

RESULTS

CD is characterized by a reliable increase of pro-inflammatory cytokines in blood compared to healthy people: tumor necrosis factor-α (TNF-α) - by 4.45 times (137.46 ± 9.72 vs. 30.88 ± 2.08 pg/ml in healthy people, p < 0,001), interleukin-1α (IL-1α) - by 5.08 times (51.55 ± 4.36 vs. 10.14 ± 0.93 pg/ml, p < 0.001), interleukin-6 (IL-6) - by 2.16 times (20.03 ± 1.81 vs. 9.27 ± 0.52 pg/ml, p < 0.001), interleukin-8 (IL-8) - by 2.04 times (25.74 ± 2.05 vs. 12.62 ± 1.16 pg/ml, p < 0.001), and interferon-γ (IFN-γ) - by 5.30 times (208.63 ± 14.29 vs. 39.35 ± 2.40 pg/ml, p < 0.001). The authors have established direct correlations between the Crohn's disease activity index and blood content of TNF-α (r = 0.84, p < 0.013), INF-γ (r = 0.61, p < 0.028); between TNF-α and INF-γ content (r = 0.67, p < 0.023), IL-1α (r = 0.49, p < 0.042), IL-6 (r = 0.40, p < 0.045), and IL-8 (r = 0.51, p < 0.033); INF-γ and IL-1α (r = 0.53, p < 0.040), IL-6 (r = 0.37, p < 0.039), IL-8 (r = 0.44, p < 0.040).

CONCLUSIONS

Patients with CD were found to have multiple cytokines (TNF-α, IL-1α, IL-6, IL-8, and IFN-γ,). The content of cytokines correlated positively with the CD activity index.

Gut Mucosal Microbiome Is Perturbed in Rheumatoid Arthritis Mice and Partly Restored after TDAG8 Deficiency or Suppression by Salicylanilide Derivative

Rheumatoid arthritis (RA), an autoimmune disease, is characterized by chronic joint inflammation and pain. We previously found that the deletion of T-cell death-associated gene 8 (TDAG8) significantly reduces disease severity and pain in RA mice. Whether it is by modulating gut microbiota remains unclear. In this study, 64 intestinal samples of feces, cecal content, and cecal mucus from the complete Freund’s adjuvant-induced arthritis mouse models were compared. The α- and β-diversity indices of the microbiome were significantly lower in RA mice. Cecal mucus showed a higher ratio of Firmicutes to Bacteroidetes in RA than healthy mice, suggesting the ratio could serve as an RA indicator. Four core genera, Eubacterium_Ventriosum, Alloprevotella, Rikenella, and Treponema, were reduced in content in both feces and mucus RA samples, and could serve microbial markers representing RA progression. TDAG8 deficiency decreased the abundance of proinflammation-related Eubacterium_Xylanophilum, Clostridia, Ruminococcus, Paraprevotella, and Rikenellaceae, which reduced local mucosal inflammation to relieve RA disease severity and pain. The pharmacological block of the TDAG8 function by a salicylanilide derivative partly restored the RA microbiome to a healthy composition. These findings provide a further understanding of specific bacteria interactions with host gut mucus in the RA model. The modulation by TDAG8 on particular bacteria can facilitate microbiota-based therapy.

Regenerative medicine for digestive fistulae therapy: Benefits, challenges and promises of stem/stromal cells and emergent perspectives via their extracellular vesicles

Despite current management strategies, digestive fistulae remain extremely debilitating complications associated with significant morbidity and mortality, generating a need to develop innovative therapies in these indications. A number of clinical trials and experimental studies have thus investigated the potential of stem/stromal cells (SCs) or SC-derived extracellular vesicles (EVs) administration for post-surgical and Crohn's-associated fistulae. This review summarizes the physiopathology and current standards-of-care for digestive fistulae, along with relevant evidence from animal and clinical studies regarding SC or EV treatment for post-surgical digestive fistulae. Additionally, existing preclinical models of fistulizing Crohn's disease and results of SC therapy trials in this indication will be presented. The optimal formulation and administration protocol of SC therapy products for gastrointestinal fistula treatment and the challenges for a widespread use of darvadstrocel (Alofisel) in clinical practice will be discussed. Finally, the potential advantages of EV therapy and the obstacles towards their clinical translation will be introduced.

Isolation and phenotypic and genotypic characterization of the potential probiotic strains of Lactobacillus from the Iranian population

Among different causes of inflammatory bowel disease (IBD), the imbalance of the gut microbiome (dysbiosis) is one of the main reasons for the development of the disease. Probiotics are live microorganisms that can maintain gut microbiota by different mechanisms. We aimed to isolate and characterize the potential probiotic strains of Lactobacillus from the Iranian population. This cross-sectional study was conducted on faecal samples of 83 volunteer individuals living in Guilan Province, North Iran. The primary identification of Lactobacillus strains was performed by standard microbiological tests and confirmed by amplification of 16s rRNA specific primers. The acid and bile salt tolerance were assessed for all recovered strains. Also, the presence of 3 bacteriocins encoding genes was investigated by the PCR method. Totally, 42 samples were positive for Lactobacillus species. Acid and bile resistance assay showed that 67% and 33% of strains were resistant to acid and bile salt stress, respectively. Therefore, we found out that 28% of our Lactobacillus strains have the ability for resistance to acid and bile conditions. PCR results revealed that the prevalence of gassericin A, plantaricin S, lactacin bacteriocin genes were 16.6%, 12%, and 9.5%, respectively. Meanwhile, 5 out of 12 Lactobacillus strains that were resistant to acid and bile conditions contained one of the gassericin or plantaricin bacteriocins. We isolated 42 potential probiotic strains of Lactobacillus, of which the results of 5 strains were more promising and can be considered as potential probiotics sources for future functional products.

Effect of supplementing fava bean (Vicia faba L.) on ulcerative colitis and colonic mucosal DNA content in rats fed a high-sucrose diet

Ulcerative colitis (UC) is an inflammatory bowel disease with high morbidity. Acetic acid-induced damage of colonic mucosa in rats is a commonly used experimental animal model of UC. This research aimed to explore for the first time the ameliorative effect of dietary supplementation with fava bean on the incidence of UC in rats fed with sucrose containing diet. Rats were divided into five groups as follows: G1, control healthy rats; G2, colitic rats; G3, colitic rats fed diets containing 30% sucrose, G4, healthy rats fed diets containing 30% sucrose and G5, colitic rats fed diets containing 30% sucrose supplemented with dried ground fava bean. Colonic injury and inflammation were evaluated through a disturbance of oxidative biomarkers, a significant increase in inflammatory biomarkers and inflammatory cytokines, and histological abnormalities in colonic tissues accompanied by colonic mucosal DNA damage. Colitic rats fed on sucrose containing diet demonstrated additional histological, biochemical, and DNA alterations in colonic mucosa of rats. Dietary supplementation with dried ground fava bean significantly corrected the impaired oxidative and inflammatory biomarker levels and modulated histological features and DNA alterations. Finally, fava bean attenuated the oxidative damage and colonic injury induced by acetic acid, which confirmed its high anti-oxidant and anti-incendiary properties.

New insights into molecular mechanisms of "Cold or Hot" nature of food: When East meets West

Traditional Chinese medicines are largely adopted in China and have a key importance in the world medical system. Cold-hot nature is the important characteristics of food and Chinese Materia Medica in the traditional Chinese medicine, relating to food functions in the organism. As compared to the studies on the cold and hot nature in Chinese medicine, the research studies carried out to establish the association between cold-hot nature and food are insufficient. Intending to investigate the criteria to discriminate the cold-hot nature of food and Chinese medicine scientifically, this review collected the cold-hot nature-related literature in recent 20 years in several popular databases such as PubMed, Google Scholar, and Science Direct. This review explored that the cold and hot natures are not only linked to the chemical components such as water, carbohydrates, lipids, and amino acids, but also correlated to the biological effects, comprising of energy metabolism, inflammation response, oxidation reaction, immune response, and cell growth and proliferation. Besides, this review further put forward the possibility that cold-hot nature of food and Chinese medicine exert different biological effects on the inflammatory response via regulating the signaling pathways viz. NF-κB and MAPK. More extensive studies are needed to consider the overall connections between both the biological effects and chemical components and how food processing affects the cold-hot nature of the food.

MiR-146a rs2910164 G > C polymorphism modulates Notch-1/IL-6 signaling during infection: a possible risk factor for Crohn's disease

Background

MiR-146a, an effector mediator, targets Notch-1 and regulates the innate and adaptive immune systems response. Recently, we reported that Notch-1 signaling plays a key role in macrophage polarization and response during infection. We employed Mycobacterium avium paratuberculosis (MAP) infection in Crohn's disease (CD) as a model to demonstrate the role of Notch-1/IL-6 signaling on MCL-1 based apoptosis and intracellular MAP infection and persistence. This study was designed to investigate the impact of polymorphisms in miR146a on the immune response and infection in our MAP-CD model.

Methods

We determined the incidence of miR-146a rs2910164 G > C in 42 blood samples from clinical CD patients and controls. We also measured the effect of rs2910164 on expression of Notch-1 and IL-6, and plasma IL-6 protein levels in our study group. Finally, we analyzed the blood samples for MAP DNA and studied any correlation with miR-146a polymorphism. Samples were analyzed for statistical significance using unpaired tow-tailed t-test, unpaired two-tailed z-score and odds ratio. P < 0.05 considered significant.

Results

MiR-146a rs2910164 GC was detected at a higher incidence in CD (52.6%) compared to healthy controls (21.7%) rs2910164 GC Heterozygous polymorphism upregulated Notch-1 and IL-6, by 0.9 and 1.7-fold, respectively. As expected, MAP infection was detected more in CD samples (63%) compared to healthy controls (9%). Surprisingly, MAP infection was detected at a higher rate in samples with rs2910164 GC (67%) compared to samples with normal genotype (33%).

Conclusions

The data clearly associates miR-146a rs2910164 GC with an overactive immune response and increases the risk to acquire infection. The study is even more relevant now in our efforts to understand susceptibility to SARS-CoV-2 infection and the development of COVID-19. This study suggests that genetic variations among COVID-19 patients may predict who is at a higher risk of acquiring infection, developing exacerbating symptoms, and possibly death. A high scale study with more clinical samples from different disease groups is planned.

Inhibitory Effects of the Lactobacillus rhamnosus GG Effector Protein HM0539 on Inflammatory Response Through the TLR4/MyD88/NF-кB Axis

Inflammatory bowel disease (IBD) is a chronic and relapsing intestinal inflammatory condition with no effective treatment. Probiotics have gained wide attention because of their outstanding advantages in intestinal health issues. In previous studies, a novel soluble protein, HM0539, which is derived from Lactobacillus rhamnosus GG (LGG), showed significant protective effects against murine colitis, but no clear precise mechanism for this effect was provided. In this study, we hypothesized that the protective function of HM0539 might be derived from its modulation of the TLR4/Myd88/NF-κB axis signaling pathway, which is a critical pathway widely involved in the modulation of inflammatory responses. To test this hypothesis, the underlying anti-inflammatory effects and associated mechanisms of HM0539 were determined both in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages and in dextran sulfate sodium (DSS)-induced murine colitis. Our results showed that HM0539 inhibited the expression of cyclooxygenase-2 (COX-2) and the expression inducible nitric oxide synthase (iNOS) by down-regulating the activation of their respective promoter, and as a result this inhibited the production of prostaglandin E2 (PGE2) and nitric oxide (NO). Meanwhile, we demonstrated that HM0539 could ultimately modulate the activation of distal NF-κB by reducing the activation of TLR4 and suppressing the transduction of MyD88. However, even though the overexpression of TLR4 or MyD88 obviously reversed the effect of HM0539 on LPS-induced inflammation, HM0539 still retained some anti-inflammatory activity. Consistent with the in vitro findings, we found that HM0539 inhibited to a great extent the production of inflammatory mediators associated with the suppression of the TLR4/Myd88/NF-κB axis activation in colon tissue. In conclusion, HM0539 was shown to be a promising anti-inflammatory agent, at least in part through its down-regulation of the TLR4-MyD88 axis as well as of the downstream MyD88-dependent activated NF-κB signaling, and hence might be considered as a potential therapeutic option for IBD.

Are Fried Foods Unhealthy? The Dietary Peroxidized Fatty Acid, 13-HPODE, Induces Intestinal Inflammation In Vitro and In Vivo

Inflammatory Bowel Disease (IBD) is a chronic inflammatory disorder characterized by progressive inflammation and the erosion of the gut mucosa. Although the exact cause of IBD is unknown, multiple factors contribute to its complex pathogenesis. Diet is one such factor and a strong correlation exists between the western-style, high fat diets (HFDs) and IBD incidence rates. In this study, we propose that the peroxidized fatty acid components of HFDs could contribute to inflammation of the gut. The inflammatory nature of peroxidized linoleic acid (13-HPODE), was confirmed in vitro by analyzing pro-inflammatory gene expression in Caco-2 cells via RT-PCR and ELISA. Additionally, peroxide induced apoptosis was tested by Annexin-V fluorescent staining, while permeability was tested by FITC-dextran flux and TEER. The 13-HPODE-induced inflammation of intestinal epithelium was evaluated in vivo by analyzing pro-inflammatory cytokines under acute and chronic conditions after feeding 13-HPODE to C57BL/6J mice. Our data show that 13-HPODE significantly induced pro-inflammatory gene expression of TNF-α and MCP-1 in vitro, most notably in differentiated Caco-2 cells. Further, acute and chronic 13-HPODE treatments of mice similarly induced pro-inflammatory cytokine expression in the epithelium of both the proximal and distal small intestines, resident immune cells in Peyer's patches and peritoneal macrophages. The results of this study not only confirm the pro-inflammatory properties of peroxidized fats on the gut mucosa, but for the first time demonstrate their ability to differentially induce pro-inflammatory gene expression and influence permeability in the intestinal epithelium and mucosal cells. Collectively, our results suggest that the immunogenic properties of HFD's in the gut may be partly caused by peroxide derivatives, providing potential insight into how these diets contribute to exacerbations of IBD.

Probiotics of Diverse Origin and Their Therapeutic Applications: A Review

The increased awareness about the harmful effects of excessive use of antibiotics has created an interest in probiotics due to its beneficial effects on gut microbiota. These advantages of probiotics have attracted researchers to find out effects on human metabolism and their role in the treatment of diverse types of diseases or disorders. Additionally, they are clinically used as biocontrol agents in the treatment of mental disorders, anticancer agents and in decreasing the threat of necrotizing enterocolitis in premature infants. In this review, we have focused on various kinds of probiotics and various nondairy substrates for their production. We have also included the importance of probiotics in the treatment of metabolic disorders, type II diabetes and infectious diseases. Furthermore, this review emphasizes applications of probiotics originated from different organisms. Their future health perspectives are discussed to gain insight into their applications.KEY TEACHING POINTSThe global market of probiotics is enormously rising day by day due to its highly beneficial effect on human microbiota.Additionally, these are used as biocontrol agents; mental disorders prevent cancer and decrease the threat of necrotizing enterocolitis (NEC) in premature infants.This review focuses on various kinds of sources of probiotics and various non-dairy substrates for the production of probiotics.The importance of probiotics in the treatment of metabolic disorders, type II diabetes control, cancer and treatment of infectious diseases are also described.It emphasizes diversified probiotics and their applications in various human health aspects and future perspectives.

Remission in Crohn's disease is accompanied by alterations in the gut microbiota and mucins production

Previous studies have demonstrated that patients with Crohn’s disease (CD) in remission do not exhibit an improvement in gut microbiota composition, which might trigger relapses. The present study investigated the dysbiosis and mucins production in CD patients during remission. We performed an analytical cross-sectional single center study, which recruited 18 CD patients and 18 healthy controls (CG) residing in the same home, meaning that all of the participants experienced the same environmental factors, with similar hygiene status, diet, pollution and other common lifestyle characteristics that may influence the composition of the gut microbiota. When compared to healthy controls, the CD patients exhibited lower microbial α-diversity (p = 0.047), a greater abundance of the Proteobacteria phylum (p = 0.037) and a reduction in the Deltaproteobacteria class (p = 0.0006). There was also a reduction in the Akkermansia (p = 0.002) and Oscillospira (p = 0.024) genera and in the proportion of the yeast Saccharomyces cerevisiae (p = 0.01). Additionally, CD patients in remission presented increased neutral (p = 0.001) and acid mucin (p = 0.002) concentrations. The reductions in the proportions of Oscollospira and Akkermansia genera, sulfate-reducing bacteria and Saccharomyces cerevisiae, observed in the CD group, may account for the increased mucins production observed in these patients.

Efficacy of budesonide-loaded mesoporous silica microparticles capped with a bulky azo derivative in rats with TNBS-induced colitis

A colon targeted drug delivery system for inflammatory bowel diseases (IBD), consisting in budesonide loaded mesoporous silica microparticles functionalized with a selective azo-molecular gate (M-Bud), has been evaluated for in vivo efficacy. Experimental colitis in male Wistar rats was induced by rectal instillation of 2,4,6-trinitrobenzenesulfonic acid (TNBS). M-Bud was orally administered to the rats as a suspension in water. Colon/body weight ratio, clinical activity score, and histological evaluation were used as inflammatory indices to measure the performance of the microparticles. The formulation was compared with a suspension prepared from the commercial drug Entocord®. Statistical analyses of all scores indicate that the controlled release of budesonide in colon from M-Bud showed efficacy similar to that of Entocord in the healing of induced colitis in rats.

Probiotics in Autoimmune and Inflammatory Disorders

Probiotics have been used to ameliorate gastrointestinal symptoms since ancient times. Over the past 40 years, probiotics have been shown to impact the immune system, both in vivo and in vitro. This interaction is linked to gut microbes, their polysaccharide antigens, and key metabolites produced by these bacteria. At least four metabolic pathways have been implicated in mechanistic studies of probiotics, based on mechanistic studies in animal models. Microbial⁻immune system crosstalk has been linked to: short-chain fatty acid production and signaling, tryptophan metabolism and the activation of aryl hydrocarbon receptors, nucleoside signaling in the gut, and activation of the intestinal histamine-2 receptor. Several randomized controlled trials have now shown that microbial modification by probiotics may improve gastrointestinal symptoms and multiorgan inflammation in rheumatoid arthritis, ulcerative colitis, and multiple sclerosis. Future work will need to carefully assess safety issues, selection of optimal strains and combinations, and attempts to prolong the duration of colonization of beneficial microbes.

Female mice carrying a defective Alox15 gene are protected from experimental colitis via sustained maintenance of the intestinal epithelial barrier function

Lipoxygenases (ALOXs) are involved in the regulation of cellular redox homeostasis. They also have been implicated in the biosynthesis of pro- and anti-inflammatory lipid mediators and play a role in the pathogenesis of inflammatory diseases, which constitute a major health challenge owing to increasing incidence and prevalence in all industrialized countries around the world. To explore the pathophysiological role of Alox15 (leukocyte-type 12-LOX) in mouse experimental colitis we tested the impact of systemic inactivation of the Alox15 gene on the extent of dextrane sulfate sodium (DSS) colitis. We found that in wildtype mice expression of the Alox15 gene was augmented during DSS-colitis while expression of other Alox genes (Alox5, Alox15b) was hardly altered. Systemic Alox15 (leukocyte-type 12-LOX) deficiency induced less severe colitis symptoms and suppressed in vivo formation of 12-hydroxyeicosatetraenoic acid (12-HETE), the major Alox15 (leukocyte-type 12-LOX) product in mice. These alterations were paralleled by reduced expression of pro-inflammatory gene products, by sustained expression of the zonula occludens protein 1 (ZO-1) and by a less impaired intestinal epithelial barrier function. These results are consistent with in vitro incubations of colon epithelial cells, in which addition of 12S-HETE compromised enantioselectively transepithelial electric resistance. Consistent with these data transgenic overexpression of human ALOX15 intensified the inflammatory symptoms. In summary, our results indicate that systemic Alox15 (leukocyte-type 12-LOX) deficiency protects mice from DSS-colitis. Since exogenous 12-HETE compromises the expression of the tight junction protein ZO-1 the protective effect has been related to a less pronounced impairment of the intestinal epithelial barrier function.