Helicobacter pylori Infection Aggravates Dysbiosis of Gut Microbiome in Children With Gastritis

Gut-brain axis interplay via STAT3 pathway: Implications of Helicobacter pylori derived secretome on inflammation and Alzheimer's disease

Helicobacter pylori is a pathogenic bacterium that causes gastritis and gastric carcinoma. Besides gastric complications its potential link with gut-brain axis disruption and neurological disorders has also been reported. The current study investigated the plausible role and its associated molecular mechanism underlying H. pylori mediated gut-brain axis disruption and neuroinflammation leading to neurological modalities like Alzheimer's disease (AD). We have chosen the antimicrobial resistant and susceptible H. pylori strains on the basis of broth dilution method. We have observed the increased inflammatory response exerted by H. pylori strains in the gastric as well as in the neuronal compartment after treatment with Helicobacter pylori derived condition media (HPCM). Further, elevated expression of STAT1, STAT3, and AD-associated proteins- APP and APOE4 was monitored in HPCM-treated neuronal and neuron-astrocyte co-cultured cells. Excessive ROS generation has been found in these cells. The HPCM treatment to LN229 causes astrogliosis, evidenced by increased glial fibrillary acidic protein. Our results indicate the association of STAT3 as an important regulator in the H. pylori-mediated pathogenesis in neuronal cells. Notably, the inhibition of STAT3 by its specific inhibitor, BP-1-102, reduced the expression of pSTAT3 and AD markers in neuronal compartment induced by HPCM. Thus, our study demonstrates that H. pylori infection exacerbates inflammation in AGS cells and modulates the activity of STAT3 regulatory molecules. H. pylori secretome could affect neurological compartments by promoting STAT3 activation and inducing the expression of AD-associated signature markers. Further, pSTAT-3 inhibition mitigates the H. pylori associated neuroinflammation and amyloid pathology.

Immunological relationship between Helicobacter pylori and anti-tumor necrosis factor α agents in inflammatory bowel disease

Inflammatory bowel disease (IBD) is a group of diseases characterized by refractory and chronic inflammation of the bowel, which can be treated with biologics in clinical practice. Anti-tumor necrosis factor α (TNF-α) agents, which are among the most widely used biologics, alleviate the inflammatory activity in a variety of ways. Helicobacter pylori is a Gram-negative bacterium that colonizes the gastric mucosa, which could cause chronic inflammation and even induce gastric cancer. However, it has been suggested that H. pylori has a potential protective role in IBD patients. Yet there has been limited research on the mechanisms of the effect of H. pylori infection in IBD patients, and whether there is an interaction between H. pylori and anti-TNF-α agents. This review aims to summarize the possible mechanisms of H. pylori and anti-TNF-α agents in the development and treatment of IBD, and to explore the possible interaction between H. pylori infection and anti-TNF-α agents.

Effects of Helicobacter pylori infection on intestinal microbiota, immunity and colorectal cancer risk

Infecting about half of the world´s population, Helicobacter pylori is one of the most prevalent bacterial infections worldwide and the strongest known risk factor for gastric cancer. Although H. pylori colonizes exclusively the gastric epithelium, the infection has also been associated with various extragastric diseases, including colorectal cancer (CRC). Epidemiological studies reported an almost two-fold increased risk for infected individuals to develop CRC, but only recently, direct causal and functional links between the chronic infection and CRC have been revealed. Besides modulating the host intestinal immune response, H. pylori is thought to increase CRC risk by inducing gut microbiota alterations. It is known that H. pylori infection not only impacts the gastric microbiota at the site of infection but also leads to changes in bacterial colonization in the distal large intestine. Considering that the gut microbiome plays a driving role in CRC, H. pylori infection emerges as a key factor responsible for promoting changes in microbiome signatures that could contribute to tumor development. Within this review, we want to focus on the interplay between H. pylori infection, changes in the intestinal microbiota, and intestinal immunity. In addition, the effects of H. pylori antibiotic eradication therapy will be discussed.

Diversification and deleterious role of microbiome in gastric cancer

Gut microbiota dictates the fate of several diseases, including cancer. Most gastric cancers (GC) belong to gastric adenocarcinomas (GAC). Helicobacter pylori colonizes the gastric epithelium and is the causative agent of 75% of all stomach malignancies globally. This bacterium has several virulence factors, including cytotoxin-associated gene A (CagA), vacuolating cytotoxin (VacA), and outer membrane proteins (OMPs), all of which have been linked to the development of gastric cancer. In addition, bacteria such as Escherichia coli, Streptococcus, Clostridium, Haemophilus, Veillonella, Staphylococcus, and Lactobacillus play an important role in the development of gastric cancer. Besides, lactic acid bacteria (LAB) such as Bifidobacterium, Lactobacillus, Lactococcus, and Streptococcus were found in greater abundance in GAC patients. To identify potential diagnostic and therapeutic interventions for GC, it is essential to understand the mechanistic role of H. pylori and other bacteria that contribute to gastric carcinogenesis. Furthermore, understanding bacteria-host interactions and bacteria-induced inflammatory pathways in the host is critical for developing treatment targets for gastric cancer.

Review of Phytochemical Potency as a Natural Anti-Helicobacter pylori and Neuroprotective Agent

Phytochemicals are plant secondary metabolites that show health benefits for humans due to their bioactivity. There is a huge variety of phytochemicals that have already been identified, and these compounds can act as antimicrobial and neuroprotection agents. Due to their anti-microbial activity and neuroprotection, several phytochemicals might have the potency to be used as natural therapeutic agents, especially for Helicobacter pylori infection and neurodegenerative disease, which have become a global health concern nowadays. According to previous research, there are some connections between H. pylori infection and neurodegenerative diseases, especially Alzheimer's disease. Hence, this comprehensive review examines different kinds of phytochemicals from natural sources as potential therapeutic agents to reduce H. pylori infection and improve neurodegenerative disease. An additional large-scale study is needed to establish the connection between H. pylori infection and neurodegenerative disease and how phytochemicals could improve this condition.

Insights into Microbiota in Sjögren's Syndrome

Primary Sjögren's syndrome (pSS) is a heterogeneous chronic autoimmune disorder with multiple clinical manifestations that can develop into non-Hodgkin's lymphoma in mucosa-associated lymphoid tissue. The pathogenesis of Sjögren's syndrome (SS) is not completely understood, but it is assumed that pathogenesis of SS is multifactorial. The microbiota plays a notable role in the development of autoimmune disorders, including Sjögren's syndrome. Molecular mimicry, metabolite changes and epithelial tolerance breakdown are pathways that might help to clarify the potential contribution of the microbiota to SS pathogenesis. This review aims to provide an overview of recent studies describing microbiota changes and microbiota mechanisms associated with Sjögren's syndrome. Data on the microbiota in SS from PubMed, Web of Science, Scopus and the Cochrane Library databases are summarized. Overall, the microbiota makes a major contribution to the development of Sjögren's syndrome and progression. Future microbiota studies should improve the management of this heterogeneous autoimmune disease.

Crosstalk between Helicobacter pylori and gastrointestinal microbiota in various gastroduodenal diseases-A systematic review

Gastroduodenal diseases have prevailed for a long time and more so due to dominance of gut bacteria Helicobacter pylori in most of the cases. But habitation by other gut microbiota in gastroduodenal diseases and the relationship between Helicobacter pylori and gastrointestinal microbiota in different gastroduodenal diseases is somewhat being unravelled in the current times. For this systematic review, we did a literature search of various gastroduodenal diseases and the effect on gut microbiota pertaining to it. A search of the online bibliographic databases PUBMED and PUBMED CENTRAL was carried out to identify articles published between 1977 and May 2022. The analysis of these selected studies highlighted the inhabitation of other gut microbiota such as Fusobacteria, Bacteroidetes, Streptococcaceae, Prevotellaceae, Fusobacteriaceae, and many others. Interplay between these microbiota and H. pylori have also been noted which suggested that gastroduodenal diseases and gut microbiota are intertwined by a symbiotic association regardless of the H. pylori status. The relationship between the gut microbiota and many gastroduodenal diseases, such as gastritis, gastric cancer, lymphomas, and ulcers, demonstrates the dysbiosis of the gut microbiota in both the presence and absence of H. pylori. The evolving ways for eliminating H. pylori are provided along with inhibiting qualities of other species on H. pylori. Most significant member of our gut system is Helicobacter pylori which has been associated with numerous diseases like gastric cancer, gastritis, duodenal ulcer.

Prevalence of Helicobacter pylori Antibiotic Resistance in Patients Enrolled in Guangzhou, China

PURPOSE

Helicobacter pylori (H. pylori) infection is a high-risk factor for the occurrence of gastric cancer. The quadruple therapy has been widely used as the first-line treatment for H. pylori in China. However, the increasing resistance rate to antibiotics has become a major challenge in the treatment of H. pylori. Therefore, there is an urgent need for rapid and cost-effective detection of antibiotic resistance to different antibiotics. To evaluate the prevalence of H. pylori antibiotic resistance in Guangzhou and the diagnostic performance of DOB value of 13C UBT in predicting antibiotic resistance.

PATIENTS AND METHODS

In this retrospective study, we collected data from 193 H. pylori culture-positive patients in Guangzhou on their DOB values and resistance to antibiotics. We analyzed the antibiotic resistance rate of commonly used antibiotics in quadruple therapy, and the diagnostic efficacy of DOB value was evaluated.

RESULTS

The resistance rates of clarithromycin (CLA) and levofloxacin (LEV) were 46.1% and 44.0%, respectively. In the age group under 40, the resistance rate of LEV was lower than that of CLA. However, the diagnostic efficacy of DOB value was found to be low and it could not serve as an independent indicator for diagnosing resistance to CLA and LEV.

CONCLUSION

The high resistance rates of CLA and LEV in H. pylori patients in Guangzhou indicate the urgent need for effective detection methods. The DOB value is not a direct indicator of antibiotic resistance to CLA and LEV. Therefore, it is important to use a combination of diagnostic methods to accurately assess antibiotic resistance in H. pylori infection.

Gut microbiota and Sjögren's syndrome: a two-sample Mendelian randomization study

Background

The link between the gut microbiota (GM) and Sjögren's Syndrome (SS) is well-established and apparent. Whether GM is causally associated with SS is uncertain.

Methods

The MiBioGen consortium's biggest available genome-wide association study (GWAS) meta-analysis (n=13,266) was used as the basis for a two-sample Mendelian randomization study (TSMR). The causal relationship between GM and SS was investigated using the inverse variance weighted, MR-Egger, weighted median, weighted model, MR-PRESSO, and simple model methods. In order to measure the heterogeneity of instrumental variables (IVs), Cochran's Q statistics were utilized.

Results

The results showed that genus Fusicatenibacter (odds ratio (OR) = 1.418, 95% confidence interval (CI), 1.072-1.874, P = 0.0143) and genus Ruminiclostridium9 (OR = 1.677, 95% CI, 1.050-2.678, P = 0.0306) were positively correlated with the risk of SS and family Porphyromonadaceae (OR = 0.651, 95% CI, 0.427-0.994, P = 0.0466), genus Subdoligranulum (OR = 0.685, 95% CI, 0.497-0.945, P = 0.0211), genus Butyricicoccus (OR = 0.674, 95% CI, 0.470-0.967, P = 0.0319) and genus Lachnospiraceae (OR = 0.750, 95% CI, 0.585-0.961, P = 0.0229) were negatively correlated with SS risk using the inverse variance weighted (IVW) technique. Furthermore, four GM related genes: ARAP3, NMUR1, TEC and SIRPD were significant causally with SS after FDR correction (FDR<0.05).

Conclusions

This study provides evidence for either positive or negative causal effects of GM composition and its related genes on SS risk. We want to provide novel approaches for continued GM and SS-related research and therapy by elucidating the genetic relationship between GM and SS.

Factors associated with treatment failure, and possible applications of probiotic bacteria in the arsenal against Helicobacter pylori

INTRODUCTION

Helicobacter pylori is a widespread helical Gram-negative bacterium, which causes a variety of stomach disorders, such as peptic ulcer, chronic atrophic gastritis, and gastric cancer. This microbe frequently colonizes the mucosal layer of the human stomach and survives in the inhospitable microenvironment, by adapting to this hostile milieu.

AREAS COVERED

In this extensive review, we describe conventional antibiotic treatment regimens used against H. pylori including, empirical, tailored, and salvage therapies. Then, we present state-of-the-art information about reasons for treatment failure against H. pylori. Afterward, the latest advances in the use of probiotic bacteria against H. pylori infection are discussed. Finally, we propose a polymeric bio-platform to provide efficient delivery of probiotics for H. pylori infection.

EXPERT OPINION

For effective probiotic delivery systems, it is necessary to avoid the early release of probiotics at the acidic stomach pH, to protect them against enzymes and antimicrobials, and precisely target H. pylori bacteria which have colonized the antrum area of the stomach (basic pH).

Dysbiosis of gut microbiota due to diet, alcohol intake, body mass index, and gastrointestinal diseases in India

The human gut is composed of diverse microflora which is influenced by dietary intake. Body mass index (BMI) and lifestyle patterns also play a vital role in human health to alter gut microbial composition. Our study aims to determine the impact of alcohol intake, BMI, and diet on gut microbiota and its relationship with gastrointestinal disorders. Thirty-nine gastric biopsies were taken from patients with various gastrointestinal (GI) diseases, and all the patient's lifestyle behavior were recorded in a written proforma. 16S rRNA metagenome analysis for V3-V4 regions was used to examine microbial compositions. The richness and diversity of gut microbiota were analyzed by PERMANOVA using the Bray-Curtis dissimilarity index and principal component analysis. The difference in relative abundance was calculated by ANOVA (p < 0.05). Alpha diversity indexes between vegetarians and non-vegetarians showed no significant difference based on BMI, alcohol status, and GI diseases. We found that in overweight vegetarian individuals Faecalibacterium and Rumicococcus might play a role in the control of Helicobacter pylori. Similarly, the increased abundance of Akkermansia muciniphila in non-vegetarian individuals with normal BMI might play a role to decrease the level of harmful bacteria like H. pylori, and Corynebacterium sp. Also, the relative abundance of Corynebacterium sp. among the vegetarians and Streptococcus sp. in the non-vegetarians was increased in alcoholics while H. pylori was increased in non-alcoholics irrespective of diet. There is an increased abundance of Faecalibacterium prausnitzii in vegetarians among all categories; however, we did not find any correlation between disease outcomes. Our study shows that alcohol intake and dietary habits have independent effects on gut microbial composition. The relative abundance of F. prausnitzii was high among vegetarians in all categories. KEY POINTS: • The presence of H. pylori is less among alcoholics. • Good bacteria help to maintain a normal body mass index. • Gut microbiota richness is high in vegetarians and diversity in non-vegetarians.

Is Helicobacter pylori Anyway Pathogen in Children?

Helicobacter pylori (H. pylori) infection is a continuous challenge for both gastroenterologists and pediatricians. The international guidelines regarding diagnostic and treatment pathways differ between adults and children. The pediatric guidelines are more restrictive because children are rarely affected by serious consequences, particularly in Western countries. Therefore, infected children should be treated only after a careful case-by-case evaluation by a pediatric gastroenterologist. In any case, recent studies are confirming an increasingly all-around pathological role of H. pylori even in asymptomatic children. For these reasons, following the current evidence, we feel that H. pylori-infected children could be treated starting in pre-adolescence, particularly in Eastern countries, because their stomachs have already begun to develop the biomarkers of gastric damage. Therefore, we believe that H. pylori is anyway pathogen in children. Nevertheless, the possible beneficial role of H. pylori in humans has not yet been conclusively disproved.

Gastrointestinal microbiome and primary Sjögren's syndrome: a review of the literature and conclusions

The recognition of the profound impact of the human gastrointestinal microbiome (GM) on human autoimmune diseases has gradually increased thanks to deeper research efforts. As a systemic autoimmune disease, primary Sjögren's syndrome (pSS) cannot be completely cured. Human studies have revealed that GM species and diversity are altered in patients with pSS compared with healthy individuals. Animal studies have provided possible mechanisms for the association between pSS and GM. The potential role of GM in pSS is exerted through several mechanisms. GM dysbiosis leads to increased intestinal permeability, which increases the risk of GM antigen exposure and activates specific autoreactive T lymphocytes via "molecular mimicry". In addition, GM antigen exposure and intestinal immune tolerance loss caused by GM dysbiosis together induce chronic local gut mucosal inflammation, which deteriorates to systemic chronic non-specific inflammation with the circulation of pro-inflammatory lymphocytes and cytokines. These factors eventually activate autoreactive B lymphocytes and lead to pSS. If GM plays a key role in the pathogenesis of pSS, clarifying the underlying mechanisms will be helpful for the development of new therapies targeting GM for dry eye associated with pSS. This review summarizes the latest knowledge about the relationship between GM and pSS, with the aim of contributing to future research and to the development of new clinical applications.

The double-edged sword of probiotic supplementation on gut microbiota structure in Helicobacter pylori management

As Helicobacter pylori management has become more challenging and less efficient over the last decade, the interest in innovative interventions is growing by the day. Probiotic co-supplementation to antibiotic therapies is reported in several studies, presenting a moderate reduction in drug-related side effects and a promotion in positive treatment outcomes. However, the significance of gut microbiota involvement in the competence of probiotic co-supplementation is emphasized by a few researchers, indicating the alteration in the host gastrointestinal microbiota following probiotic and drug uptake. Due to the lack of long-term follow-up studies to determine the efficiency of probiotic intervention in H. pylori eradication, and the delicate interaction of the gut microbiota with the host wellness, this review aims to discuss the gut microbiota alteration by probiotic co-supplementation in H. pylori management to predict the comprehensive effectiveness of probiotic oral administration.Abbreviations: acyl-CoA- acyl-coenzyme A; AMP- antimicrobial peptide; AMPK- AMP-activated protein kinase; AP-1- activator protein 1; BA- bile acid; BAR- bile acid receptor; BCAA- branched-chain amino acid; C2- acetate; C3- propionate; C4- butyrate; C5- valeric acid; CagA- Cytotoxin-associated gene A; cAMP- cyclic adenosine monophosphate; CD- Crohn's disease; CDI- C. difficile infection; COX-2- cyclooxygenase-2; DC- dendritic cell; EMT- epithelial-mesenchymal transition; FMO- flavin monooxygenases; FXR- farnesoid X receptor; GPBAR1- G-protein-coupled bile acid receptor 1; GPR4- G protein-coupled receptor 4; H2O2- hydrogen peroxide; HCC- hepatocellular carcinoma; HSC- hepatic stellate cell; IBD- inflammatory bowel disease; IBS- irritable bowel syndrome; IFN-γ- interferon-gamma; IgA immunoglobulin A; IL- interleukin; iNOS- induced nitric oxide synthase; JAK1- janus kinase 1; JAM-A- junctional adhesion molecule A; LAB- lactic acid bacteria; LPS- lipopolysaccharide; MALT- mucosa-associated lymphoid tissue; MAMP- microbe-associated molecular pattern; MCP-1- monocyte chemoattractant protein-1; MDR- multiple drug resistance; mTOR- mammalian target of rapamycin; MUC- mucin; NAFLD- nonalcoholic fatty liver disease; NF-κB- nuclear factor kappa B; NK- natural killer; NLRP3- NLR family pyrin domain containing 3; NOC- N-nitroso compounds; NOD- nucleotide-binding oligomerization domain; PICRUSt- phylogenetic investigation of communities by reconstruction of unobserved states; PRR- pattern recognition receptor; RA- retinoic acid; RNS- reactive nitrogen species; ROS- reactive oxygen species; rRNA- ribosomal RNA; SCFA- short-chain fatty acids; SDR- single drug resistance; SIgA- secretory immunoglobulin A; STAT3- signal transducer and activator of transcription 3; T1D- type 1 diabetes; T2D- type 2 diabetes; Th17- T helper 17; TLR- toll-like receptor; TMAO- trimethylamine N-oxide; TML- trimethyllysine; TNF-α- tumor necrosis factor-alpha; Tr1- type 1 regulatory T cell; Treg- regulatory T cell; UC- ulcerative colitis; VacA- Vacuolating toxin A.

The interplay between Helicobacter pylori and the gut microbiota: An emerging driver influencing the immune system homeostasis and gastric carcinogenesis

The human gut microbiota are critical for preserving the health status because they are required for digestion and nutrient acquisition, the development of the immune system, and energy metabolism. The gut microbial composition is greatly influenced by the colonization of the recalcitrant pathogen Helicobacter pylori (H. pylori) and the conventional antibiotic regimens that follow. H. pylori is considered to be the main microorganism in gastric carcinogenesis, and it appears to be required for the early stages of the process. However, a non-H. pylori microbiota profile is also suggested, primarily in the later stages of tumorigenesis. On the other hand, specific groups of gut microbes may produce beneficial byproducts such as short-chain fatty acids (acetate, butyrate, and propionate) that can modulate inflammation and tumorigenesis pathways. In this review, we aim to present how H. pylori influences the population of the gut microbiota to modify the host immunity and trigger the development of gastric carcinogenesis. We will also highlight the effect of the gut microbiota on immunotherapeutic approaches such as immune checkpoint blockade in cancer treatment to present a perspective for further development of innovative therapeutic paradigms to prevent the progression of H. pylori-induced stomach cancer.

Gut Commensal Parabacteroides goldsteinii MTS01 Alters Gut Microbiota Composition and Reduces Cholesterol to Mitigate Helicobacter pylori-Induced Pathogenesis

Helicobacter pylori infection is closely associated with various gastrointestinal diseases and poses a serious threat to human health owing to its increasing antimicrobial resistance. H. pylori possesses two major virulence factors, vacuolating cytotoxin A (VacA) and cytotoxin-associated gene A (CagA), which are involved in its pathogenesis. Probiotics have recently been used to eradicate H. pylori infection and reduce the adverse effects of antibiotic-based therapies. Parabacteroides goldsteinii MTS01 is a novel next-generation probiotic (NGP) with activities that can alleviate specific diseases by altering the gut microbiota. However, the mechanism by which P. goldsteinii MTS01 exerts its probiotic effects against H. pylori infection remains unclear. Our results showed that administration of P. goldsteinii MTS01 to H. pylori-infected model mice altered the composition of the gut microbiota and significantly reduced serum cholesterol levels, which mitigated H. pylori-induced gastric inflammation. In addition, the pathogenic effects of H. pylori VacA and CagA on gastric epithelial cells were markedly abrogated by treatment with P. goldsteinii MTS01. These results indicate that P. goldsteinii MTS01 can modulate gut microbiota composition and has anti-virulence factor functions, and thus could be developed as a novel functional probiotic for reducing H. pylori-induced pathogenesis.

Red yeast rice dietary intervention reduces oxidative stress-related inflammation and improves intestinal microbiota

Inflammation and oxidative stress play key roles in the aging process, while red yeast rice (RYR), a traditional Chinese fermented food, has anti-oxidant and anti-inflammatory effects. To understand the anti-aging function of RYR in vivo, this study established a D-galactose-induced aging mouse model to verify the positive effects of RYR dietary intervention on aging and explore the related underlying mechanism. Eight weeks of RYR dietary intervention was shown to have a significant inhibitory effect on cognitive decline and hippocampal damage. The molecular mechanistic studies showed that the anti-aging effects of RYR were achieved by (i) improving the oxidative stress-related damage (increasing SOD, CAT, and GSH, and reducing MDA), (ii) regulating the NF-κB inflammation pathway induced by oxidative stress (decreasing the pro-inflammatory cytokines IL-6, TNF-α, IFN-γ, iNOs, and IL-1β, increasing the anti-inflammatory cytokine IL-10, and decreasing the expression of the NF-κB protein), (iii) slowing down apoptosis caused by oxidative stress (reducing the expression of P21 and P53), (iv) restoring the abundance of Lactobacillus, Lachnospiraceae and Rikenellaceae downregulated by D-galactose, and (v) reducing the abundance of Akkermansia and Helicobacter enriched by D-galactose. Mass spectrometry revealed orange pigments (rubropunctatin and monascorubrin) as the main antioxidant components in RYR, which might play key roles in aging inhibition. This study provides theoretical support for the wide application of orange pigments as an antioxidant dietary supplement.

Peptic Ulcer and Gastric Cancer: Is It All in the Complex Host-Microbiome Interplay That Is Encoded in the Genomes of "Us" and "Them"?

It is increasingly being recognized that severe gastroduodenal diseases such as peptic ulcer and gastric cancer are not just the outcomes of Helicobacter pylori infection in the stomach. Rather, both diseases develop and progress due to the perfect storms created by a combination of multiple factors such as the expression of different H. pylori virulence proteins, consequent human immune responses, and dysbiosis in gastrointestinal microbiomes. In this mini review, we have discussed how the genomes of H. pylori and other gastrointestinal microbes as well as the genomes of different human populations encode complex and variable virulome–immunome interplay, which influences gastroduodenal health. The heterogeneities that are encrypted in the genomes of different human populations and in the genomes of their respective resident microbes partly explain the inconsistencies in clinical outcomes among the H. pylori-infected people.

Clinical Factors Implicated in Antibiotic Resistance in Helicobacter pylori Patients

Helicobacter pylori is a common gastric pathogen associated with multiple clinical syndromes, including cancer. Eradication rates of H. pylori remain suboptimal despite the progress made in the past few decades in improving treatment strategies. The low eradication rates are mainly driven by antibiotic resistance of H. pylori. Non-invasive molecular testing to identify patients with antibiotic-resistant H. pylori represents a promising therapeutic avenue, however this technology currently remains limited by availability, costs, and lack of robust validation. Moreover, there is insufficient evidence to demonstrate that resistance-testing-based treatment approaches are superior to appropriately designed empiric strategies. Consensus guidelines recommend use of proven locally effective regimens; however, eradication data are inconsistently generated in several regions of the world. In this review, we describe several clinical factors associated with increased rates of antibiotic resistant H. pylori, including history of previous antibiotic exposure, increasing age, female gender, ethnicity/race, extent of alcohol use, and non-ulcer dyspepsia. Assessment of these factors may aid the clinician in choosing the most appropriate empiric treatment strategy for each patient. Future study should aim to identify locally effective therapies and further explore the clinical factors associated with antibiotic resistance.

Periodontitis, Helicobacter pylori infection, and gastrointestinal tract cancer mortality

AIM

Periodontitis has been proposed to lead to Helicobacter pylori infection, which could cause many gastrointestinal tract cancers. This study aimed to determine the association or otherwise between periodontitis and survival outcomes in individuals with respect to H. pylori infection.

MATERIALS AND METHODS

The study population comprised 4955 subjects aged 20-90 who had received both periodontal examination and H. pylori serum test in the Third National Health and Nutrition Examination Survey (NHANES III) database. Logistic regression models were used to analyse the association between periodontitis and H. pylori seropositivity (H. pylori infection). Survival analysis was performed using the NHANES III linked to mortality data. Cox proportional hazard regression was carried out to investigate the association between periodontitis and gastrointestinal tract cancer mortality in individuals with/without H. pylori infection.

RESULTS

Compared to periodontal health, periodontitis was significantly associated with increased odds of H. pylori infection (OR = 1.271, 95% CI = 1.177-1.372). Periodontitis significantly increased the mortality risk from all causes (HR = 1.574, 95% CI = 1.327-1.866) and all cancers (HR = 1.948, 95% CI = 1.701-2.232), including gastrointestinal (GI) tract cancer (HR = 4.140, 95% CI = 3.656-4.687), gastric cancer (HR = 4.288, 95% CI = 3.969-4.632), and colorectal cancer (HR = 4.814, 95% CI = 3.849-6.020) in subjects with H. pylori infection after adjusting for health-related factors. Periodontitis was significantly related to the decreased survival time in subjects with GI tract (p = .001) or colorectal cancer (p = .002) and H. pylori infection.

CONCLUSION

Our study demonstrated that periodontitis was significantly associated with higher mortality risk of GI tract, gastric, and colorectal cancer in subjects with H. pylori infection. Owing to an interactive effect between periodontitis and H. pylori infection on cancer mortality, H. pylori infection has a significant moderating effect in regulating the association between periodontitis and mortality due to all cancers, including GI tract cancer and colorectal cancer.

Progress in elucidating the relationship between Helicobacter pylori infection and intestinal diseases

Helicobacter pylori (H. pylori) infection causes changes to the intestinal flora, such as small intestinal bacterial overgrowth, and increases gastric acid secretion-stimulating gastrointestinal hormones, mainly gastrin, due to a decrease in gastric acid caused by atrophic gastritis. In addition, the cellular components of H. pylori travel through the intestinal tract, so the bacterial infection affects the immune system. Therefore, the effects of H. pylori infection are observed not only in the stomach and the proximal duodenum but also in the small and large intestines. In particular, meta-analyses reported that H. pylori-infected individuals had an increased risk of colorectal adenoma and colorectal cancer. Moreover, a recent study reported that the risk of developing colorectal cancer was increased in subjects carrying H. pylori vacuolating cytotoxin A antibody. In addition, it has been reported that H. pylori infection exacerbates the symptoms of Fabry’s disease and familial Mediterranean fever attack and is involved in irritable bowel syndrome and small intestinal ulcers. On the other hand, some studies have reported that the frequency of ulcerative colitis, Crohn’s disease, and celiac disease is low in H. pylori-infected individuals. Thus, H. pylori infection is considered to have various effects on the small and large intestines. However, few studies have reported on these issues, and the details of their effects have not been well elucidated. Therefore, additional studies are needed.

Helicobacter pylori and the intestinal microbiome among healthy school-age children

BACKGROUND

Helicobacter pylori (H. pylori) infection is acquired during childhood and causes chronic gastritis that remains asymptomatic in most infected people. H. pylori alters the gastric microbiota and causes peptic ulcer disease. Evidence on the relationship between asymptomatic H. pylori infection and children's gut microbiota remains elusive.

AIM

We characterized the relationship between H. pylori infection and the intestinal microbiome of healthy children, adjusting for known inter-personal and environmental exposures.

MATERIALS AND METHODS

This cross-sectional study included stool samples obtained from 163 Israeli Arab children aged 6-9 years from different socioeconomic strata. Sociodemographic information was collected through maternal interviews. H. pylori infection was determined using monoclonal antigen detection stool enzyme immunoassay. The gut microbiome was characterized by implementing 16S rRNA gene sequencing of the V4 region and a multivariate downstream analysis.

RESULTS

Overall, 57% of the participants were positive for H. pylori infection and it was significantly associated with low socioeconomic status. There was no significant association between H. pylori infection and bacterial richness of fecal microbiome. H. pylori infection was significantly associated with intestinal bacterial composition, including a strong association with Prevotella copri and Eubacterium biforme. Moreover, socioeconomic status was strongly associated with bacterial composition.

DISCUSSION AND CONCLUSIONS

H. pylori infection in healthy children was significantly associated with altered intestinal microbiome structure. Socioeconomic determinants exhibit a strong effect, related to both H. pylori infection and intestinal diversity and composition in childhood. These findings are clinically important to the understanding of the role of H. pylori infection and other intestinal microbes in health and disease.

Interplay and cooperation of Helicobacter pylori and gut microbiota in gastric carcinogenesis

Chronic Helicobacter pylori infection is a critical risk factor for gastric cancer (GC). However, only 1–3 % of people with H. pylori develop GC. In gastric carcinogenesis, non-H. pylori bacteria in the stomach might interact with H. pylori. Bacterial dysbiosis in the stomach can strengthen gastric neoplasia development via generating tumor-promoting metabolites, DNA damaging, suppressing antitumor immunity, and activating oncogenic signaling pathways. Other bacterial species may generate short-chain fatty acids like butyrate that may inhibit carcinogenesis and inflammation in the human stomach. The present article aimed at providing a comprehensive overview of the effects of gut microbiota and H. pylori on the development of GC. Next, the potential mechanisms of intestinal microbiota were discussed in gastric carcinogenesis. We also disserted the complicated interactions between H. pylori, intestinal microbiota, and host in gastric carcinogenesis, thus helping us to design new strategies for preventing, diagnosing, and treating GC.

Role of Helicobacter pylori and Other Environmental Factors in the Development of Gastric Dysbiosis

Microbiomes are defined as complex microbial communities, which are mainly composed of bacteria, fungi, and viruses residing in diverse regions of the human body. The human stomach consists of a unique and heterogeneous habitat of microbial communities owing to its anatomical and functional characteristics, that allow the optimal growth of characteristic bacteria in this environment. Gastric dysbiosis, which is defined as compositional and functional alterations of the gastric microbiota, can be induced by multiple environmental factors, such as age, diet, multiple antibiotic therapies, proton pump inhibitor abuse, H. pylori status, among others. Although H. pylori colonization has been reported across the world, chronic H. pylori infection may lead to serious consequences; therefore, the infection must be treated. Multiple antibiotic therapy improvements are not always successful because of the lack of adherence to the prescribed antibiotic treatment. However, the abuse of eradication treatments can generate gastric dysbiotic states. Dysbiosis of the gastric microenvironment induces microbial resilience, due to the loss of relevant commensal bacteria and simultaneous colonization by other pathobiont bacteria, which can generate metabolic and physiological changes or even initiate and develop other gastric disorders by non-H. pylori bacteria. This systematic review opens a discussion on the effects of multiple environmental factors on gastric microbial communities.

Helicobacter pylori infection and antibiotic resistance - from biology to clinical implications

Helicobacter pylori is a major human pathogen for which increasing antibiotic resistance constitutes a serious threat to human health. Molecular mechanisms underlying this resistance have been intensively studied and are discussed in this Review. Three profiles of resistance - single drug resistance, multidrug resistance and heteroresistance - seem to occur, probably with overlapping fundamental mechanisms and clinical implications. The mechanisms that have been most studied are related to mutational changes encoded chromosomally and disrupt the cellular activity of antibiotics through target-mediated mechanisms. Other biological attributes driving drug resistance in H. pylori have been less explored and this could imply more complex physiological changes (such as impaired regulation of drug uptake and/or efflux, or biofilm and coccoid formation) that remain largely elusive. Resistance-related attributes deployed by the pathogen cause treatment failures, diagnostic difficulties and ambiguity in clinical interpretation of therapeutic outcomes. Subsequent to the increasing antibiotic resistance, a substantial drop in H. pylori treatment efficacy has been noted globally. In the absence of an efficient vaccine, enhanced efforts are needed for setting new treatment strategies and for a better understanding of the emergence and spread of drug-resistant bacteria, as well as for improving diagnostic tools that can help optimize current antimicrobial regimens.

Impact of Dietary Patterns on H. pylori Infection and the Modulation of Microbiota to Counteract Its Effect. A Narrative Review

Helicobacter pylori (H. pylori) is a Gram-negative bacterium that colonizes the stomach and can induce gastric disease and intra-gastric lesions, including chronic gastritis, peptic ulcers, gastric adenocarcinoma, and mucosa-associated lymphoid tissue lymphoma. This bacterium is responsible for long-term complications of gastric disease. The conjunction of host genetics, immune response, bacterial virulence expression, diet, micronutrient availability, and microbiome structure influence the disease outcomes related to chronic H. pylori infection. In this regard, the consumption of unhealthy and unbalanced diets can induce microbial dysbiosis, which infection with H. pylori may contribute to. However, to date, clinical trials have reported controversial results and current knowledge in this field is inconclusive. Here, we review preclinical studies concerning the changes produced in the microbiota that may be related to H. pylori infection, as well as the involvement of diet. We summarize and discuss the last approaches based on the modulation of the microbiota to improve the negative impact of H. pylori infection and their potential translation from bench to bedside.

Effects of cat ownership on the gut microbiota of owners

Pet ownership is an essential environmental exposure that might influence the health of the owner. This study’s primary objectives were to explore the effects of cat ownership on the gut microbial diversity and composition of owners. Raw data from the American Gut Project were obtained from the SRA database. A total of 214 Caucasian individuals (111 female) with cats and 214 individuals (111 female) without cats were used in the following analysis. OTU number showed significant alteration in the Cat group and Female_cat group, compared with that of the no cat (NC) group and Female_ NC group, respectively. Compared with the NC group, the microbial phylum Proteobacteria was significantly decreased in the Cat group. The microbial families Alcaligenaceae and Pasteurellaceae were significantly reduced, while Enterobacteriaceae and Pseudomonadaceae were significantly increased in the Cat group. Fifty metabolic pathways were predicted to be significantly changed in the Cat group. Twenty-one and 13 metabolic pathways were predicted to be significantly changed in the female_cat and male_cat groups, respectively. Moreover, the microbial phylum Cyanobacteria was significantly decreased, while the families Alcaligenaceae, Pseudomonadaceae and Enterobacteriaceae were significantly changed in the normal weight cat group. In addition, 41 and 7 metabolic pathways were predicted to be significantly changed in the normal-weight cat and overweight cat groups, respectively. Therefore, this study demonstrated that cat ownership could influence owners’ gut microbiota composition and function, especially in the female group and normal-weight group.

Interactions between H. pylori and the Gastric Microbiome: Impact on Gastric Homeostasis and Disease

Like many seemingly inhospitable environments on our planet, the highly acidic human stomach harbors a diverse bacterial microflora. The best-known member of the human gastric flora, Helicobacter pylori, causes a number of gastric diseases, including peptic ulcer disease and gastric adenocarcinoma. In the absence of Helicobacter pylori infection, the gastric microbiota displays some features similar to the oral cavity with Firmicutes the most common phylum, followed by Proteobacteria and Bacteroidetes. When present, H. pylori dominates the gastric microbiome and reduces diversity and composition of other taxa. The composition of the gastric microbiome also is altered in the setting of proton pump inhibitor therapy and gastric neoplasia. This review summarizes foundational and recent studies that have investigated the composition of the human gastric microbiome in a variety of patient groups, with a focus on potential mechanisms involved in regulation of gastric microbial community structure.

Bacteriostatic Potential of Melatonin: Therapeutic Standing and Mechanistic Insights

Diseases caused by pathogenic bacteria in animals (e.g., bacterial pneumonia, meningitis and sepsis) and plants (e.g., bacterial wilt, angular spot and canker) lead to high prevalence and mortality, and decomposition of plant leaves, respectively. Melatonin, an endogenous molecule, is highly pleiotropic, and accumulating evidence supports the notion that melatonin's actions in bacterial infection deserve particular attention. Here, we summarize the antibacterial effects of melatonin in vitro, in animals as well as plants, and discuss the potential mechanisms. Melatonin exerts antibacterial activities not only on classic gram-negative and -positive bacteria, but also on members of other bacterial groups, such as Mycobacterium tuberculosis. Protective actions against bacterial infections can occur at different levels. Direct actions of melatonin may occur only at very high concentrations, which is at the borderline of practical applicability. However, various indirect functions comprise activation of hosts' defense mechanisms or, in sepsis, attenuation of bacterially induced inflammation. In plants, its antibacterial functions involve the mitogen-activated protein kinase (MAPK) pathway; in animals, protection by melatonin against bacterially induced damage is associated with inhibition or activation of various signaling pathways, including key regulators such as NF-κB, STAT-1, Nrf2, NLRP3 inflammasome, MAPK and TLR-2/4. Moreover, melatonin can reduce formation of reactive oxygen and nitrogen species (ROS, RNS), promote detoxification and protect mitochondrial damage. Altogether, we propose that melatonin could be an effective approach against various pathogenic bacterial infections.

The preparation of bifunctional hybrid nano-flowers and their application in the enzyme-linked immunosorbent assay for Helicobacter pylori detection

As the infection by Helicobacter pylori (H. pylori, HP) remains for a lifetime and may induce diseases such as gastric cancer, it is vital to detect and diagnose it. A new non-invasive indirect enzyme-linked immunosorbent assay (iELISA) method based on nano-flowers (NFs) is very advantageous for the sensitive detection of HP. Furthermore, the established iELISA method based on the organic-inorganic bifunctional hybrid nano-flowers including rabbit polyclonal antibody of HP labeled with peroxidase from horseradish (R-HP-Ab-HRP@Cu2+ NFs) showed linearity with HP at a concentration of 0-105 CFU mL-1 (R2 = 0.9997). Moreover, the limit of detection (LOD) reached 50 CFU mL-1, and not only was the detection sensitivity 20 times higher than that based on rabbit polyclonal antibody of HP labeled with peroxidase from horseradish (R-HP-Ab-HRP) but also the stability of R-HP-Ab-HRP in NFs was improved. In addition, the OD450 nm value was still linearly related to the concentration of HP at a range of 0-105 CFU mL-1 (R2 = 0.9952) with a LOD of 50 CFU mL-1 in an artificial saliva system. This study provided a sensitive, low-cost and convenient method for the non-invasive detection of HP.

Helicobacter pylori infection is correlated with the incidence of erosive oral lichen planus and the alteration of the oral microbiome composition

BACKGROUND

Oral lichen planus (OLP), a common clinical oral disease, is associated with an increased risk of malignant transformation. The mechanism underlying the pathogenesis of OLP is unknown. Oral dysbacteriosis is reported to be one of the aetiological factors of OLP. Although Helicobacter pylori infection is associated with various oral diseases, the correlation between H. pylori infection and OLP is unclear. This study aimed to investigate the effect of H. pylori infection on OLP pathogenesis and oral microbiome composition in the Chinese population, which has a high incidence of H. pylori infection.

RESULT

In this study, saliva samples of 30 patients with OLP (OLP group) and 21 negative controls (NC group) were collected. H. pylori infection was detected using the carbon-13-labeled urea breath test (UBT). The saliva samples were divided into the following four groups based on the H. pylori status: H. pylori-positive OLP (OLP+), H. pylori-positive NC (NC+), H. pylori-negative OLP (OLP-), and H. pylori-negative NC (NC-). Oral microbiome compositions were significantly different between the OLP and NC groups and between the OLP- and OLP+ groups. Compared with those in the OLP- group, those in the OLP+ group had a higher incidence of erosive OLP and higher levels of salivary cytokines. In contrast, the oral microbiome composition and cytokine levels were not significantly different between the NC- and NC+ groups.

CONCLUSIONS

This is the first report to demonstrate that H. pylori infection is significantly correlated with the pathogenesis of erosive OLP.

How peptic ulcer disease could potentially lead to the lifelong, debilitating effects of chronic fatigue syndrome: an insight

Chronic Fatigue Syndrome (CFS) has been defined as unexplained relapsing or persistent fatigue for at least 6 consecutive months. Immuno-inflammatory pathway, bacterial infection, and other causes play essential roles in CFS. Helicobacter pylori infection is one of the most common causes of foregut inflammation, leading to peptic ulcer disease (PUD). This study aimed to analyze the risk of CFS development between patients with and without PUD. Other related factors were also analyzed. We performed a retrospective, nationwide cohort study identifying patients with or without PUD respectively by analyzing the Longitudinal Health Insurance Database 2000 (LHID2000), Taiwan. The overall incidence of CFS was higher in the PUD cohort than in the non- PUD cohort (HR = 2.01, 95% CI = 1.75-2.30), with the same adjusted HR (aHR) when adjusting for age, sex, and comorbidities. The sex-specific PUD cohort to the non-PUD cohort relative risk of CFS was significant in both genders. The age-specific incidence of CFS showed incidence density increasing with age in both cohorts. There is an increased risk of developing CFS following PUD, especially in females and the aging population. Hopefully, these findings can prevent common infections from progressing to debilitating, chronic conditions such as CFS.

Precision Medicine and Public Health: New Challenges for Effective and Sustainable Health

The development of high-throughput omics technologies represents an unmissable opportunity for evidence-based prevention of adverse effects on human health. However, the applicability and access to multi-omics tests are limited. In Italy, this is due to the rapid increase of knowledge and the high levels of skill and economic investment initially necessary. The fields of human genetics and public health have highlighted the relevance of an implementation strategy at a national level in Italy, including integration in sanitary regulations and governance instruments. In this review, the emerging field of public health genomics is discussed, including the polygenic scores approach, epigenetic modulation, nutrigenomics, and microbiomes implications. Moreover, the Italian state of implementation is presented. The omics sciences have important implications for the prevention of both communicable and noncommunicable diseases, especially because they can be used to assess the health status during the whole course of life. An effective population health gain is possible if omics tools are implemented for each person after a preliminary assessment of effectiveness in the medium to long term.

Helicobacter pylori infection worsens impaired glucose regulation in high-fat diet mice in association with an altered gut microbiome and metabolome

Emerging evidence suggests that Helicobacter pylori infection is associated with metabolic disorders, although the underlying mechanisms are poorly defined. This study aimed to investigate the interaction among H. pylori, a high-fat diet (HFD), and the gut microbiota with glucose regulation and alterations in microbial metabolites. Mice were randomly allocated to H. pylori-infected and noninfected groups fed a chow diet or an HFD. After 4 weeks, two of the HFD groups were given antibiotic cocktails for 8 weeks to eliminate the gut microbiota. The results showed that an HFD significantly promoted increases in body weight, insulin resistance, and glucose intolerance, which were alleviated to normal after antibiotic treatment. H. pylori infection aggravated HFD-induced hyperglycemia, which could not be restored by antibiotics. The perturbation of the gut microbiota was greater in the mice cotreated with H. pylori and an HFD (HFDHp) compared to those administered either H. pylori or an HFD alone, with a loss of diversity, higher abundance of Helicobacter, and lower abundance of Lactobacillus. Furthermore, compared to that of the HFD alone group, the gut microbiota of the HFDHp group was much more susceptible to antibiotic destruction, with extremely lower diversity and dominance of Klebsiella. Fecal metabolome analyses demonstrated that the combination of H. pylori infection and an HFD altered metabolic composition and function, which were linked to glucose dysregulation. H. pylori infection may exacerbate the dysbiosis of the gut microenvironment induced by an HFD, including alterations in the microbiota and metabolites, which weakens the restorative effect of antibiotics and results in the persistence of glucose disorders. KEY POINTS: • The interplay of Hp, HFD, and antibiotics on glucose metabolism was firstly explored. • Hp infection impaired the effect of antibiotics on HFD-induced glucose dysregulation. • Hp infection altered gut microbiota and metabolites which aggravated by HFD.

The interplay between Helicobacter pylori and gastrointestinal microbiota

The complex population of microbes in the human gastrointestinal (GI) tract interacts with itself and with the host, exerting a deep influence on health and disease development. The development of modern sequencing technology has enabled us to gain insight into GI microbes. Helicobacter pylori colonization significantly affects the gastric microenvironment, which in turn affects gastric microbiota and may be correlated with colonic microbiota changes. Crosstalk between H. pylori and GI commensal flora may play a role in H. pylori-related carcinogenicity and extragastric manifestations. We review current knowledge on how H. pylori shapes GI microbiota with a specific focus on its impact on the stomach and colon. We also review current evidence on colonic microbiota changes attributed to eradication therapy based on the clinical studies performed to date.

Helicobacter pylori Related Diseases and Osteoporotic Fractures (Narrative Review)

Osteoporosis (OP) and osteoporotic fractures (OFs) are common multifactorial and heterogenic disorders of increasing incidence. Helicobacter pylori (H.p.) colonizes the stomach approximately in half of the world's population, causes gastroduodenal diseases and is prevalent in numerous extra-digestive diseases known to be associated with OP/OF. The studies regarding relationship between H.p. infection (HPI) and OP/OFs are inconsistent. The current review summarizes the relevant literature on the potential role of HPI in OP, falls and OFs and highlights the reasons for controversies in the publications. In the first section, after a brief overview of HPI biological features, we analyze the studies evaluating the association of HPI and bone status. The second part includes data on the prevalence of OP/OFs in HPI-induced gastroduodenal diseases (peptic ulcer, chronic/atrophic gastritis and cancer) and the effects of acid-suppressive drugs. In the next section, we discuss the possible contribution of HPI-associated extra-digestive diseases and medications to OP/OF, focusing on conditions affecting both bone homeostasis and predisposing to falls. In the last section, we describe clinical implications of accumulated data on HPI as a co-factor of OP/OF and present a feasible five-step algorithm for OP/OF risk assessment and management in regard to HPI, emphasizing the importance of an integrative (but differentiated) holistic approach. Increased awareness about the consequences of HPI linked to OP/OF can aid early detection and management. Further research on the HPI-OP/OF relationship is needed to close current knowledge gaps and improve clinical management of both OP/OF and HPI-related disorders.

Review: Helicobacter pylori infection in children

Helicobacter pylori infection in children and adolescents differs in comparison to adults with respect to epidemiology, host responses, and disease manifestations. Furthermore, treatment options are limited in this population and antibiotic resistance rates continue to increase. Therefore, ongoing research is vital to understand disease pathogenesis and provide optimal management of children with infection. This review summarizes relevant publications from April 2019 to March 2020. Similar to adults, recent studies show a decreasing prevalence of infection in the pediatric population. Studies of pathogenesis investigated serum immune responses and the potential inverse association of infection and allergy. Several studies investigated the effect of H pylori and related inflammation on the gut microbiome. The recommendation of endoscopy-based testing to identify the cause of symptoms and not just H pylori, reserving noninvasive UBT or stool antigen tests for post-eradication follow-up, was supported by the current literature.

Antioxidant activity of selenium-enriched Chrysomyia megacephala (Fabricius) larvae powder and its impact on intestinal microflora in D-galactose induced aging mice

Background

The purpose of this study was to assess the antioxidative activity of selenium-enriched Chrysomyia Megacephala (Fabricius) (C. megacephala) larvae powder (SCML) and its impact on the diversity and structure of intestinal microflora in a mouse model of D-galactose (D-gal)-induced oxidative damage.

Methods

Sixty male ICR mice were equally randomized to a normal control (NC) group, a model group, a positive group, a low-dose SCML (L-SCML) group, a mid-dose SCML (M-SCML) group, and a high-dose SCML (H-SCML) group. Animals in NC and model groups received water, animals in the positive group received 40 mg/Kg vitamin E (VE), and those in the three SCML groups received SCML which include 300, 1000 and 3000 μg/Kg selenium (Se) respectively. An oxidative damage model induced by subcutaneous injection of D-gal for 6 weeks via the neck was established. Serum oxidative stress levels and tissue appearance were evaluated. Tissues oxidative stress levels were detected by commercially available kit. Nuclear erythroid 2-related factor (Nrf2) and gut microbiota were determined by western blot and high throughput sequencing 16S rRNA gene respectively.

Results

An oxidative damage model was established successfully as represented by a significant elevation of malondialdehyde (MDA) and protein carbonylation, and inhibition of the antioxidants including superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), total antioxidant capacity (T-AOC) and glutathione (GSH). It was found that oxidative damage and histological alterations were attenuated, the expression of Kelch-like ECH-associated protein (Keap1) was decreased, and the expression of Nrf2 and hemeoxygenase-1 (HO-1) was increased after SCML treatment. In addition, significant changes were observed in the gut microbiota, including Proteobacteria and the ratio of Bacteroidetes to Firmicutes at the phylum level, as well as Helicobacter, Clostridium and Lactobacillus at the genus level.

Conclusion

SCML exerted an antioxidative effect in vivo, probably by increasing the antioxidant activity and reducing the production of oxidation products via the Nrf2 signaling pathway. SCML could also redress the intestinal flora imbalance induced by oxidative stress. All these findings suggest that SCML could serve as a functional food and natural drug additive to protect the human body against oxidative damage.