Trophic transfer of micro- and nanoplastics and toxicity induced by long-term exposure of nanoplastics along the rotifer (Brachionus plicatilis)-marine medaka (Oryzias melastigma) food chain

Microplastics (MPs) and nanoplastics (NPs) are emerging pollutants in the ocean, but their transfer and toxicity along the food chains are unclear. In this study, a marine rotifer (Brachionus plicatilis)-marine medaka (Oryzias melastigma) food chain was constructed to evaluate the transfer of polystyrene MPs and NPs (70 nm, 500 nm, and 2 μm, 2000 μg/L) and toxicity of 70 nm PS-NPs (0, 20, 200, and 2000 μg/L) on marine medaka after long-term food chain exposure. The results showed that the amount of 70 nm NPs accumulated in marine medaka was 1.24 μg/mg, which was significantly higher than that of 500 nm NPs (0.87 μg/mg) and 2 μm MP (0.69 μg/mg). Long-term food chain exposure to NPs caused microflora dysbiosis, resulting in activation of toll-like receptor 4 (TLR4) pathway, which induced liver inflammation. Moreover, NPs food chain exposure increased liver and muscle tissue triglyceride and lactate content, but decreased the protein, sugar, and glycogen content. NPs food chain exposure impaired reproductive function and inhibited offspring early development, which might pose a threat to the sustainability of marine medaka population. Overall, the study revealed the transfer of MPs and NPs and the effects of NPs on marine medaka along the food chain.

Ocular microbial dysbiosis and its linkage with infectious keratitis patients in Northwest China: A cross-sectional study

OBJECTIVES

To evaluate the alteration of ocular surface microbiome of patients with infectious keratitis in northwest of China.

METHODS

The corneal scrapings, eyelid margin and conjunctiva samples were collected from 57 participants, who were divided into bacterial keratitis, fungal keratitis, viral keratitis and control group. The V3-V4 region of bacterial 16S rDNA in each sample was amplified and sequenced on the Illumina HiSeq 2500 sequencing platform, and the differences among different groups were compared bioinformatically.

RESULTS

Significant alterations of the microbiome were observed in alpha-diversity and beta-diversity analysis between the keratitis groups and the control group (p < 0.05). There was no significant differences between eyelid margin and conjunctiva samples in Alpha-Diversity analysis, but a significant difference between eyelid margin and corneal scraping samples in the keratitis group (p < 0.05, independent t-test). The abundances of Bacillus, Megamonas, Acinetobacter, and Rhodococcu were significantly elevated, while the abundance of Staphylococcus was decreased in the keratitis group compared to the control group.

CONCLUSIONS

The abundance of the ocular microbiome in patients with bacterial keratitis, fungal keratitis, or viral keratitis was significantly higher than those in the control group. Keratitis patients may have ecological disorder on ocular surface microbiome compared with controls. We believe that the conjunctiva and eyelid margin microbiome combined analysis can more comprehensively reflect the composition and abundance of ocular surface microbiome.

Skin microbial dysbiosis is a characteristic of systemic drug-related intertriginous and flexural exanthema-like lesions induced by EGFR inhibitor

Objectives

To investigate the characteristics of the skin microbiome in severe afatinib-induced skin toxicity.

Methods

Body site-matched skin surface samples were collected from the lesions on seven flexural sites of one lung cancer (Patient 1) with serious systemic drug-related intertriginous and flexural exanthema (SDRIFE)-like toxicity induced by EGFR-TKI and three healthy age/sex matched controls for whole metagenomics sequencing analysis. Lung cancer Patient 1 and Patient 2 were prescribed minocycline and followed up.

Results

In SDRIFE-like toxicities induced by afatinib, lesion microbiota richness (ACE and Chao1 index: p < 0.001) and diversity (Shannon's and Simpson's diversity indices: p < 0.01) were reduced. Similarly, the beta diversity analysis (R = 1, p = 0.002 for ANOSIM) showed that the apparent difference in the microbiota composition was statistically significant. The microbial taxa composition in the patient showed an increased abundance of pathogenic bacteria and a decreased abundance of commensal bacteria. LEfSe analysis identified strong bacterial pathogenicity in the patient, while healthy controls exhibited enrichment in several pathways that are beneficial for skin commensal bacteria and skin physiology, including key amino acid metabolism, energy/lipid/glycan biosynthesis/metabolism, and cofactors/vitamins biosynthesis. Ultimately, the patients experienced significant improvement with minocycline.

Conclusion

Microbial dysbiosis is a characteristic of severe SDRIFE-like toxicity induced by afatinib.

Oral Microbiota as a Diagnostic Biomarker of Digestive Cancer: A Systematic Review

AIM

This article aimed to review the association of oral microbiota with digestive cancer (DC).

BACKGROUND

Oral microbiota is one of the most complex ecosystems in our body. The mouth, from which the digestive system starts, may be a source of an abundant taxonomic group of microbiotas that travel to the digestive system followed by growth, reproduction, and settlement, forming a complex microecological environment causing systemic and gastrointestinal (GI) disease.

REVIEW RESULTS

A total of 14 articles were chosen for review. Most studies were case-control. Both positive and negative associations were seen between oral microbiome and DC.

CONCLUSION

Digestive cancer may be associated with distinctive oral microbial character.

CLINICAL SIGNIFICANCE

The present systematic review enlightens the risk of digestive carcinoma with oral microbiota that may act as a biomarker for early diagnosis of DC in a more comfortable, acceptable, and noninvasive way. How to cite this article: Ikbal SKA, Yadav SK, Mehrotra R, et al. Oral Microbiota as a Diagnostic Biomarker of Digestive Cancer: A Systematic Review. J Contemp Dent Pract 2023;24(11):902-911.

Diet-microbiome-immune interplay in multiple sclerosis: Understanding the impact of phytoestrogen metabolizing gut bacteria

Multiple sclerosis (MS) is a chronic and progressive autoimmune disease of the central nervous system (CNS), with both genetic and environmental factors contributing to the pathobiology of the disease. Although HLA genes have emerged as the strongest genetic factor linked to MS, consensus on the environmental risk factors is lacking. Recently, the gut microbiota has garnered increasing attention as a potential environmental factor in MS, as mounting evidence suggests that individuals with MS exhibit microbial dysbiosis (changes in the gut microbiome). Thus, there has been a strong emphasis on understanding the role of the gut microbiome in the pathobiology of MS, specifically, factors regulating the gut microbiota and the mechanism(s) through which gut microbes may contribute to MS. Among all factors, diet has emerged to have the strongest influence on the composition and function of gut microbiota. As MS patients lack gut bacteria capable of metabolizing dietary phytoestrogen, we will specifically discuss the role of a phytoestrogen diet and phytoestrogen metabolizing gut bacteria in the pathobiology of MS. A better understanding of these mechanisms will help to harness the enormous potential of the gut microbiota as potential therapeutics to treat MS and other autoimmune diseases.

Diet-mediated gut microbial community modulation and signature metabolites as potential biomarkers for early diagnosis, prognosis, prevention and stage-specific treatment of colorectal cancer

BACKGROUND

Over the last decade, studies have shown an increased incidence of colorectal cancer (CRC), particularly early onset colorectal cancer (EOCRC). Researchers have demonstrated that dietary behavior, especially among young adults, influences alterations in the gut microbial community, leading to an increased accumulation of pathogenic gut microbiota and a decrease in beneficial ones. Unfortunately, CRC is likely to be diagnosed at a late stage, increasing CRC-related mortality. However, this alteration in the gut microbiota (gut dysbiosis) can be harnessed as a biomarker for non-invasive diagnosis, prognosis, prevention, and treatment of CRC in an effort to prevent late diagnosis and poor prognosis associated with CRC.

AIM OF REVIEW

This review discusses identification of potential biomarkers by targeting diet-mediated gut dysbiosis for the stage-specific diagnosis, prognosis, treatment, and prevention of CRC. Our findings provide a comprehensive insight into the potential of protumorigenic bacteria (e.g.pathogenic Escherichia coli,enterotoxigenic Bacteroides fragilis and Fusobacterium nucleatum) and their metabolites (e.g., colibactin and B. fragilis toxin) from gut dysbiosis as biomarkers for the diagnosis of CRC.

KEY SCIENTIFIC CONCEPTS OF REVIEW

Collectively, a detailed understanding of the available data from current studies suggests that, further research on quantification of metabolites and stage-specific pathogenic microbial abundance is required for the diagnosis and treatment of CRC based on microbial dysbiosis. Specifically, future studies on faecal samples, from patient with CRC, should be conducted for F. nucleatum among different opportunistic bacteria, given its repeated occurrence in faecal samples and CRC biopsies in numerous studies. Finally, we discuss the potential of faecal microbial transplantation (FMT) as an intervention to restore damaged gut microbiota during CRC treatment and management.

Gut microbiota dysbiosis and Huntington's disease: Exploring the gut-brain axis and novel microbiota-based interventions

Huntington's disease (HD) is a complex progressive neurodegenerative disorder affected by genetic, environmental, and metabolic factors contributing to its pathogenesis. Gut dysbiosis is termed as the alterations of intestinal microbial profile. Emerging research has highlighted the pivotal role of gut dysbiosis in HD, focusing on the gut-brain axis as a novel research parameter in science. This review article provides a comprehensive overview of gut microbiota dysbiosis and its relationship with HD and its pathogenesis along with the future challenges and opportunities. The focuses on the essential mechanisms which link gut dysbiosis to HD pathophysiology including neuroinflammation, immune system dysregulation, altered metabolites composition, and neurotransmitter imbalances. We also explored the impacts of gut dysbiosis on HD onset, severity, and symptoms such as cognitive decline, motor dysfunction, and psychiatric symptoms. Furthermore, we highlight recent advances in therapeutics including microbiota-based therapeutic approaches, including dietary interventions, prebiotics, probiotics, fecal microbiota transplantation, and combination therapies with conventional HD treatments and their applications in managing HD. The future challenges are also highlighted as the heterogeneity of gut microbiota, interindividual variability, establishing causality between gut dysbiosis and HD, identifying optimal therapeutic targets and strategies, and ensuring the long-term safety and efficacy of microbiota-based interventions. This review provides a better understanding of the potential role of gut microbiota in HD pathogenesis and guides the development of novel therapeutic approaches.

Association between antibiotics and adverse oncological outcomes in patients receiving targeted or immune-based therapy for hepatocellular carcinoma

Background & Aims

Immune checkpoint inhibitors (ICIs) alone or in combination with other ICIs or vascular endothelial growth factor pathway inhibitors are therapeutic options in unresectable/metastatic hepatocellular carcinoma (HCC). Whether antibiotic (ATB) exposure affects outcome remains unclear.

Methods

This study retrospectively analysed an FDA database including 4,098 patients receiving ICI (n = 842) either as monotherapy (n = 258) or in combination (n = 584), tyrosine kinase inhibitor (TKI) (n = 1,968), vascular endothelial growth factor pathway inhibitors (n = 480), or placebo (n = 808) as part of nine international clinical trials. Exposure to ATB within 30 days before or after treatment initiation was correlated with overall survival (OS) and progression-free survival (PFS) across therapeutic modality before and after inverse probability of treatment weighting (IPTW).

Results

Of 4,098 patients with unresectable/metastatic HCC, of which 39% were of hepatitis B aetiology and 21% were of hepatitis C aetiology, 83% were males with a median age of 64 years (range 18-88), a European Collaborative Oncology Group performance status of 0 (60%), and Child-Pugh A class (98%). Overall, ATB exposure (n = 620, 15%) was associated with shorter median PFS (3.6 months in ATB-exposed vs. 4.2 months; hazard ratio [HR] 1.29; 95% CI 1.22, 1.36) and OS (8.7 months in ATB-exposed vs. 10.6 months; HR 1.36; 95% CI 1.29, 1.43). In IPTW analyses, ATB was associated with shorter PFS in patients treated with ICI (HR 1.52; 95% CI 1.34, 1.73), TKI (HR 1.29; 95% CI 1.19, 1.39), and placebo (HR 1.23; 95% CI 1.11, 1.37). Similar results were observed in IPTW analyses of OS in patients treated with ICI (HR 1.22; 95% CI 1.08, 1.38), TKI (HR 1.40; 95% CI 1.30, 1.52), and placebo (HR 1.40; 95% CI 1.25, 1.57).

Conclusions

Unlike other malignancies where the detrimental effect of ATB may be more prominent in ICI recipients, ATB is associated with worse outcomes in this study across different therapies for HCC including placebo. Whether ATB is causally linked to worse outcomes through disruption of the gut-liver axis remains to be demonstrated in translational studies.

Impact and Implications

A growing body of evidence suggests the host microbiome, frequently altered by antibiotic treatment, as an important outcome predictor in the context of immune checkpoint inhibitor therapy. In this study, we analysed the effects of early antibiotic exposure on outcomes in almost 4,100 patients with hepatocellular carcinoma treated within nine multicentre clinical trials. Interestingly, early exposure to antibiotic treatment was associated with worse outcomes not only in patients treated with immune checkpoint inhibitors but also in those treated with tyrosine kinase inhibitors and placebo. This is in contrast to data published in other malignancies, where the detrimental effect of antibiotic treatment may be more prominent in immune checkpoint inhibitor recipients, highlighting the uniqueness of hepatocellular carcinoma given the complex interplay between cirrhosis, cancer, risk of infection, and the pleiotropic effect of molecular therapies for this disease.

Supplementation of quinoa peptides alleviates colorectal cancer and restores gut microbiota in AOM/DSS-treated mice

Quinoa protein hydrolysate has been previously reported to exert anti-cancer effects in cultured colon cancer cells. Here, we investigated the effect of quinoa protein and its hydrolysate on an azoxymethane/dextran sulfate sodium (AOM/DSS)-induced mouse model of colorectal cancer (CRC) and examined its underlying mechanism using gut microbiota analysis and short chain fatty acids (SCFAs) production analysis. Our results showed that quinoa protein or its hydrolysate mitigated the clinical symptoms of CRC and increased SCFAs contents in colon tissues. Moreover, administration of quinoa protein or its hydrolysate partially alleviated gut microbiota dysbiosis in CRC mice by decreasing the abundance of pathogenic bacteria and increasing the abundance of probiotics. Additionally, PICRUSt analysis revealed that the functional profile of gut microbiota in the quinoa protein treated groups was more similar to that of the control group. These findings indicated that the modulation of gut microbiota by quinoa protein diet intervention may ameliorate AOM/DSS-induced CRC.

Lung-gut axis of microbiome alterations following co-exposure to ultrafine carbon black and ozone

BACKGROUND

Microbial dysbiosis is a potential mediator of air pollution-induced adverse outcomes. However, a systemic comparison of the lung and gut microbiome alterations and lung-gut axis following air pollution exposure is scant. In this study, we exposed male C57BL/6J mice to inhaled air, CB (10 mg/m3), O3 (2 ppm) or CB + O3 mixture for 3 h/day for either one day or four consecutive days and were euthanized 24 h post last exposure. The lung and gut microbiome were quantified by 16 s sequencing.

RESULTS

Multiple CB + O3 exposures induced an increase in the lung inflammatory cells (neutrophils, eosinophils and B lymphocytes), reduced absolute bacterial load in the lungs and increased load in the gut. CB + O3 exposure was more potent as it decreased lung microbiome alpha diversity just after a single exposure. CB + O3 co-exposure uniquely increased Clostridiaceae and Prevotellaceae in the lungs. Serum short chain fatty acids (SCFA) (acetate and propionate) were increased significantly only after CB + O3 co-exposure. A significant increase in SCFA producing bacterial families (Ruminococcaceae, Lachnospiraceae, and Eubacterium) were also observed in the gut after multiple exposures. Co-exposure induced significant alterations in the gut derived metabolite receptors/mediator (Gcg, Glp-1r, Cck) mRNA expression. Oxidative stress related mRNA expression in lungs, and oxidant levels in the BALF, serum and gut significantly increased after CB + O3 exposures.

CONCLUSION

Our study confirms distinct gut and lung microbiome alterations after CB + O3 inhalation co-exposure and indicate a potential homeostatic shift in the gut microbiome to counter deleterious impacts of environmental exposures on metabolic system.

A review on Impact of dietary interventions, drugs, and traditional herbal supplements on the gut microbiome

The gut microbiome is the community of healthy, and infectious organisms in the gut and its interaction in the host gut intestine (GI) environment. The balance of microbial richness with beneficial microbes is very important to perform healthy body functions like digesting food, controlling metabolism, and precise immune function. Alternately, this microbial dysbiosis occurs due to changes in the physiochemical condition, substrate avidity, and drugs. Moreover, various categories of diet such as "plant-based", "animal-based", "western", "mediterranean", and various drugs (antibiotic and common drugs) also contribute to maintaining microbial flora inside the gut. The imbalance (dysbiosis) in the microbiota of the GI tract can cause several disorders (such as diabetes, obesity, cancer, inflammation, and so on). Recently, the major interest is to use prebiotic, probiotic, postbiotic, and herbal supplements to balance such microbial community in the GI tract. But, there has still a large gap in understanding the microbiome function, and its relation to the host diet, drugs, and herbal supplements to maintain the healthy life of the host. So, the present review is about the updates on the microbiome concerns related to diet, drug, and herbal supplements, and also gives research evidence to improve our daily habits regarding diet, drugs, and herbal supplements. Because our regular dietary plan and traditional herbal supplements can improve our health by balancing the bacteria in our gut.

Alterations of gut and oral microbiota in the individuals consuming take-away food in disposable plastic containers

Microplastics (MP) and nanoplastics (NP) exist in the disposable plastic take-away containers. This study aims to determine the gut and oral microbiota alterations in the individuals frequently and occasionally consuming take-away food in disposable plastic containers (TFDPC), and explore the effect of micro/nanoplastics (MNP) reduction on gut microbiota in mice. TFDPC consumption are associated with greater presences of gastrointestinal dysfunction and cough. Both occasional and frequent consumers have altered gut and oral microbiota, and their gut diversity and evenness are greater than those of non-TFDPC consuming cohort. Multiple gut and oral bacteria are associated with TFDPC consumers, among which intestinal Collinsella and oral Thiobacillus are most associated with the frequent consumers, while intestinal Faecalibacterium is most associated with the occasional consumers. Although some gut bacteria associated with the mice treated with 500 µg NP and 500 µg MP are decreased in the mice treated with 200 µg NP, the gut microbiota of the three MNP groups are all different from the control group. This study demonstrates that TFDPC induces gut and oral microbiota alterations in the consumers, and partial reduction of the size and amount of MNP cannot rectify the MNP-induced gut microbial dysbiosis.

Airborne polystyrene microplastics and nanoplastics induce nasal and lung microbial dysbiosis in mice

Microplastics (MP) and nanoplastics (NP) have been found in multiple environments and creatures. However, their effects on the airway microbiota still remain poorly understood. In this study, a series of bioinformatic and statistical analyses were carried out to explore the influence of airborne MP and NP on the nasal and lung microbiota in mice. Both MP and NP were capable of inducing nasal microbial dysbiosis, and MP had a stronger influence on the lung microbiota than NP. Multiple nasal and lung bacteria were associated with MP and NP groups, among which nasal Staphylococcus and lung Roseburia were most associated with MP group, while nasal Prevotella and lung unclassified_Muribaculaceae were most associated with NP group. The nasal Staphylococcus, lung Roseburia, lung Eggerthella and lung Corynebacterium were associated with both MP and NP groups, which were potential biomarkers of micro/nanoplastics-induced airway dysbiosis. SAR11_Clade_Ia and SAR11_Clade_II were associated with both nasal and lung microbiota in MP group, while no such bacterium was determined in NP group. The relevant results suggest that both airborne MP and NP could induce nasal and lung microbial dysbiosis, and the relevant preventative and curable strategies deserve further investigations.

Microbiome dysbiosis and epigenetic modulations in lung cancer: From pathogenesis to therapy

The lung microbiome plays an essential role in maintaining healthy lung function, including host immune homeostasis. Lung microbial dysbiosis or disruption of the gut-lung axis can contribute to lung carcinogenesis by causing DNA damage, inducing genomic instability, or altering the host's susceptibility to carcinogenic insults. Thus far, most studies have reported the association of microbial composition in lung cancer. Mechanistic studies describing host-microbe interactions in promoting lung carcinogenesis are limited. Considering cancer as a multifaceted disease where epigenetic dysregulation plays a critical role, epigenetic modifying potentials of microbial metabolites and toxins and their roles in lung tumorigenesis are not well studied. The current review explains microbial dysbiosis and epigenetic aberrations in lung cancer and potential therapeutic opportunities.

Smoking-induced microbial dysbiosis in health and disease

Smoking is associated with an increased risk of cancer, pulmonary and cardiovascular diseases, but the precise mechanisms by which such risk is mediated remain poorly understood. Additionally, smoking can impact the oral, nasal, oropharyngeal, lung and gut microbiome composition, function, and secreted molecule repertoire. Microbiome changes induced by smoking can bear direct consequences on smoking-related illnesses. Moreover, smoking-associated dysbiosis may modulate weight gain development following smoking cessation. Here, we review the implications of cigarette smoking on microbiome community structure and function. In addition, we highlight the potential impacts of microbial dysbiosis on smoking-related diseases. We discuss challenges in studying host–microbiome interactions in the context of smoking, such as the correlations with smoking-related disease severity versus causation and mechanism. In all, understanding the microbiome’s role in the pathophysiology of smoking-related diseases may promote the development of rational therapies for smoking- and smoking cessation-related disorders, as well as assist in smoking abstinence.

Stressful events induce long-term gut microbiota dysbiosis and associated post-traumatic stress symptoms in healthcare workers fighting against COVID-19

OBJECTIVE

The microbiota-gut-brain axis is a key pathway perturbed by prolonged stressors to produce brain and behavioral disorders. Frontline healthcare workers (FHWs) fighting against COVID-19 typically experience stressful event sequences and manifest some mental symptoms; however, the role of gut microbiota in such stress-induced mental problems remains unclear. We investigated the association between the psychological stress of FHW and gut microbiota.

METHODS

We used full-length 16S rRNA gene sequencing to characterize the longitudinal changes in gut microbiota and investigated the impact of microbial changes on FHWs' mental status.

RESULTS

Stressful events induced significant depression, anxiety, and stress in FHWs and disrupted the gut microbiome; gut dysbiosis persisted for at least half a year. Different microbes followed discrete trajectories during the half-year of follow-up. Microbes associated with mental health were mainly Faecalibacterium spp. and [Eubacterium] eligens group spp. with anti-inflammatory effects. Of note, the prediction model indicated that low abundance of [Eubacterium] hallii group uncultured bacterium and high abundance of Bacteroides eggerthii at Day 0 (immediately after the two-month frontline work) were significant determinants of the reappearance of post-traumatic stress symptoms in FHWs.

LIMITATIONS

The lack of metabolomic evidence and animal experiments result in the unclear mechanism of gut dysbiosis-related stress symptoms.

CONCLUSION

The stressful event sequences of fighting against COVID-19 induce characteristic longitudinal changes in gut microbiota, which underlies dynamic mental state changes.

Human microbial dysbiosis as driver of gynecological malignancies

Gynecological cancers that affect female reproductive tract, remain at the top of the global cancer burden list with high relapse rate and mortality. Notwithstanding development of several novel therapeutic interventions including poly-ADP-ribose polymerase inhibitors, this family of malignancies remain deadly. The human microbiome project demonstrated that dysbiosis of health resident microflora is associated with several pathologies including malignancies of the female reproductive tract and detailed characterization of species variation and host-microbe interaction could provide clues for identification of early diagnostic biomarker, preventive and therapeutic interventions. Emerging evidence suggests that several microbial signatures are significantly associated with gynecological cancers. An increased population of Proteobacteria and Firmicutes followed by significantly reduced Lactobacilli are associated with lethal epithelial ovarian cancer. Similarly, a constant association of elevated level of Atopobium vaginae, Porphyromonas somerae, Micrococci and Gardnerella vaginalis are observed in endometrial and cervical cancers. Moreover, human papilloma virus infection significantly augments colonization of pathogenic microbes including Sneathia sanguinegens, Anaerococcus tetradius, and Peptostreptococcus anaerobius and drives carcinoma of the cervix. Interestingly, microbial dysbiosis in female reproductive tract modulates expression of several microbial and immune-responsive genes such as TLR-4, TLR-5, TLR-6 and NOD-1. Therefore, stringent investigation into the microbial dysbiosis and its underlying mechanism could provide valuable cues for identification of early diagnostic biomarker, preventive and therapeutic interventions against rogue gynecological malignancies.

Microbiome composition indicate dysbiosis and lower richness in tumor breast tissues compared to healthy adjacent paired tissue, within the same women

Background

Breast cancer (BC) is the most common malignancy in women, in whom it reaches 20% of the total neoplasia incidence. Most BCs are considered sporadic and a number of factors, including familiarity, age, hormonal cycles and diet, have been reported to be BC risk factors. Also the gut microbiota plays a role in breast cancer development. In fact, its imbalance has been associated to various human diseases including cancer although a consequential cause-effect phenomenon has never been proven.

Methods

The aim of this work was to characterize the breast tissue microbiome in 34 women affected by BC using an NGS-based method, and analyzing the tumoral and the adjacent non-tumoral tissue of each patient.

Results

The healthy and tumor tissues differed in bacterial composition and richness: the number of Amplicon Sequence Variants (ASVs) was higher in healthy tissues than in tumor tissues (p = 0.001). Moreover, our analyses, able to investigate from phylum down to species taxa for each sample, revealed major differences in the two richest phyla, namely, Proteobacteria and Actinobacteria. Notably, the levels of Actinobacteria and Proteobacteria were, respectively, higher and lower in healthy with respect to tumor tissues.

Conclusions

Our study provides information about the breast tissue microbial composition, as compared with very closely adjacent healthy tissue (paired samples within the same woman); the differences found are such to have possible diagnostic and therapeutic implications; further studies are necessary to clarify if the differences found in the breast tissue microbiome are simply an association or a concausative pathogenetic effect in BC. A comparison of different results on similar studies seems not to assess a universal microbiome signature, but single ones depending on the environmental cohorts’ locations.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-09074-y.

Dysbiotic tumor microbiota associates with head and neck squamous cell carcinoma outcomes

BACKGROUND

The need for an effective tool to predict prognosis of head and neck squamous cell carcinoma (HNSCC) patients is critical and unmet. Microbiota has recently been found involved in tumor progression and response to immunotherapy. However, the association of microbiota with the prognosis of HNSCC patients remains obscure. This study aims to investigate the association between tumor microbiota and outcomes of HNSCC patients.

METHODS

A retrospective study including 129 primary tumors of HNSCC was conducted. Using 16S rRNA sequencing, the profile and the composition of tumor microbiota were measured and their associations with overall survival (OS) and disease free survival (DFS) were examined.

RESULTS

We observed a reduced richness and enriched abundances of genera Schlegelella and Methyloversatilis in tumor microbiota of HNSCC patients with poor prognosis. However, a richer tumor microbiota with greater abundances of genera Bacillus, and Lactobacillus and Sphingomonas was characterized in the patients with favorable prognosis.The ratio of these differentially abundant taxa, microbial dysbiosis index (MDI), was significantly associated with OS (hazard ratio [HR], 4.67, 95% confidence interval [CI], 2.51 to 8.69,P < 0.001) and DFS (HR, 2.89; 95% CI, 1.74 to 4.80, P < 0.001) independently of age, tumor size, lymph node metastasis, differentiation and p16 status. The risk score of multivariate Cox regression exhibited an excellent performance for estimating three-year OS (AUC of 0.826). We also found a richer tumor microbiota was correlated with moderate peritumoral inflammatory infiltration.

CONCLUSION

These results indicate that tumor microbiota associates with outcomes of HNSCC patients.

Polystyrene microplastics induce microbial dysbiosis and dysfunction in surrounding seawater

Microplastics are ubiquitously present in the environment, accumulate in aquaculture water, and cause toxicological effects on aquatic organisms. Besides, microplastics provide ecological niches for microorganisms in aquatic environments. However, the effects of microplastics on microbial balance and function in surrounding water are still unclear, especially for aquaculture water. Therefore, 16S rRNA gene sequencing was employed to uncover polystyrene microplastics (PS)-induced microbial dysbiosis in surrounding seawater cultivating marine medaka (Oryzias melastigmas) and to screen related potential bacterial biomarkers. We found that Proteobacteria and Bacteroidetes were the dominant phyla in each group, accounting for more than 95% of the total abundance, and that 26 bacterial taxa belonging to Proteobacteria and Bacteroidetes were significantly altered in surrounding seawater after 10- and 200-µm PS exposure. Functional analysis revelated that photosynthesis, carbon metabolism (such as carbon fixation, glycolysis, tricarboxylic acid cycle, and glycan biosynthesis and metabolism), amino acid metabolism, lipid synthesis, and nucleotide metabolism were decreased, while environmental stress responses, such as xenobiotics biodegradation and metabolism, glutathione metabolism, and taurine and hypotaurine metabolism, were increased in surrounding seawater microbiota after separate 10- and 200-µm PS exposure. Pathway analysis and correlation networks demonstrated that changes in relative abundances of bacterial taxa belonging to Proteobacteria and Bacteroidetes were highly correlated with those in the liver metabolism of marine medaka. Subsequently, 8 bacterial taxa were discovered to be able to be used separately as the potential biomarker for assessing the surrounding seawater microbial dysbiosis and metabolic responses of marine medaka, with a diagnostic accuracy of 100.0%. This study provides novel insights into toxicological effects of microplastics on microbial dysbiosis and function in surrounding water and ecosystems, and suggests potential roles of biomarkers involved in surrounding microbial dysbiosis in assessing microplastic ecotoxicology, microbial dysbiosis, and the health status of organisms at higher trophic levels.

Holistic perspective of the role of gut microbes in diabetes mellitus and its management

The gut microbiota (GM) plays a role in the development and progression of type 1 and type 2 diabetes mellitus (DM) and its complications. Gut dysbiosis contributes to the pathogenesis of DM. The GM has been shown to influence the efficacy of different antidiabetic medications. Intake of gut biotics, like prebiotics, probiotics and synbiotics, can improve the glucose control as well as the metabolic profile associated with DM. There is some preliminary evidence that it might even help with the cardiovascular, ophthalmic, nervous, and renal complications of DM and even contribute to the prevention of DM. More large-scale research studies are needed before wide spread use of gut biotics in clinical practice as an adjuvant therapy to the current management of DM.

Emerging Role of the Gut Microbiome in Irritable Bowel Syndrome

Advances in bioinformatics have facilitated investigation of the role of gut microbiota in patients with irritable bowel syndrome (IBS). This article describes the evidence from epidemiologic and clinical observational studies highlighting the link between IBS and gut microbiome by investigating postinfection IBS, small intestinal bacterial overgrowth, and microbial dysbiosis. It highlights the effects of gut microbiota on mechanisms implicated in the pathophysiology of IBS, including gut-brain axis, visceral hypersensitivity, motility, epithelial barrier, and immune activation. In addition, it summarizes the current evidence on microbiome-guided therapies in IBS, including probiotics, antibiotics, diet, and fecal microbiota transplant.

Calprotectin as potential novel biomarker in myasthenia gravis

Myasthenia gravis (MG) is the most common autoimmune disease affecting the neuromuscular junction by specific autoantibodies. The etiology of MG and its heterogeneity in clinical courses are poorly understood, although it was recently shown that gut microbial dysbiosis plays a critical role. Since levels of Calprotectin (CLP) seem to correlate with level of dysbiosis, we hypothesize that CLP may serve as potential disease activity biomarker in MG. Sera from 251 patients with MG and 90 controls were analyzed in an explorative, cross-sectional design. Prospectively, we tested CLP levels in MG patients up to 3 years. Association of CLP levels with socio-demographics, disease activity (quantitative myasthenia gravis (QMG) score, myasthenia gravis-specific Activities of Daily Living scale (MG-ADL)), antibody (Abs) status, history of myasthenic crisis, treatment regime, and history of thymectomy were investigated using univariate analysis. Mean baseline serum levels of CLP were significantly higher in MG patients compared to controls (4.3 μg/ml vs. 2.1 μg/ml; p < 0.0001). Higher levels of CLP were associated with a higher clinical disease severity measured by MGFA classification and QMG score. Nevertheless, the only weak correlation of CLP with clinical outcome parameters needs confirmation in future studies. Currently, there are no validated blood biomarkers for MG. The significantly elevated CLP and mild correlation with parameters of disease activity suggests that CLP holds promise as a biomarker for measurement of individual disease severity.

Subgingival microbiome of deep and shallow periodontal sites in patients with rheumatoid arthritis: a pilot study

Background

Subgingival microbiome in disease-associated subgingival sites is known to be dysbiotic and significantly altered. In patients with rheumatoid arthritis (RA), the extent of dysbiosis in disease- and health-associated subgingival sites is not clear.

Methods

8 RA and 10 non-RA subjects were recruited for this pilot study. All subjects received full oral examination and underwent collection of subgingival plaque samples from both shallow (periodontal health-associated, probing depth ≤ 3mm) and deep subgingival sites (periodontal disease-associated, probing depth ≥ 4 mm). RA subjects also had rheumatological evaluation. Plaque community profiles were analyzed using 16 S rRNA sequencing.

Results

The phylogenetic diversity of microbial communities in both RA and non-RA controls was significantly higher in deep subgingival sites compared to shallow sites (p = 0.022), and the overall subgingival microbiome clustered primarily according to probing depth (i.e. shallow versus deep sites), and not separated by RA status. While a large number of differentially abundant taxa and gene functions was observed between deep and shallow sites as expected in non-RA controls, we found very few differentially abundant taxa and gene functions between deep and shallow sites in RA subjects. In addition, compared to non-RA controls, the UniFrac distances between deep and shallow sites in RA subjects were smaller, suggesting increased similarity between deep and shallow subgingival microbiome in RA. Streptococcus parasanguinis and Actinomyces meyeri were overabundant in RA subjects, while Gemella morbillorum, Kingella denitrificans, Prevotella melaninogenica and Leptotrichia spp. were more abundant in non-RA subjects.

Conclusions

The aggregate subgingival microbiome was not significantly different between individuals with and without rheumatoid arthritis. Although the differences in the overall subgingival microbiome was driven primarily by probing depth, in contrast to the substantial microbiome differences typically seen between deep and shallow sites in non-RA patients, the microbiome of deep and shallow sites in RA patients were more similar to each other. These results suggest that factors associated with RA may modulate the ecology of subgingival microbiome and its relationship to periodontal disease, the basis of which remains unknown but warrants further investigation.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12903-021-01597-x.

Analysis of oral microbial dysbiosis associated with early childhood caries

Background

"Core microbes" play a key role in the development of caries and lead to microbial disorders. Our goal was to detect the core microbes associated with the microbiota imbalance in early childhood caries (ECC).

Methods

Fifteen caries-free children and fifteen high-caries (DMFT ≥ 10) children aged 4–6 years old were recruited according to the diagnostic criteria of caries suggested by the WHO. The 16S rRNA genes from samples of plaque in saliva were amplified by PCR, and the PCR products were sequenced by the Illumina Miseq platform. The sequencing results were analyzed by professional software to determine the composition and structure of the saliva microorganisms.

Results

There were statistically significant differences between the groups regarding the relative abundance of Streptococcus mutans (Wilcoxon rank-sum test, P < 0.05). No significant difference was found between the groups regarding other species or functional genes.

Conclusion

S. mutans, together with other pathogens, may play a prominent role and act as "core microbes" in the occurrence and development of early childhood caries.

Modeling microbe-host interaction in the pathogenesis of Crohn's disease

Alterations in the gut microbiota structure and function are thought to play an important role in the pathogenesis of Crohn's disease (CD). The rapid advancement of high-throughput sequencing technologies led to the identification of microbiome risk signatures associated with distinct disease phenotypes and progressing disease entities. Functional validation of the identified microbiome signatures is essential to understand the underlying mechanisms of microbe-host interactions. Germfree mouse models are available to study the functional role of disease-conditioning complex gut microbial ecosystems (dysbiosis) or pathobionts (single bacteria) in the pathogenesis of CD-like inflammation. Here, we discuss the clinical and mechanistic relevance and limitations of gnotobiotic mouse models in the context of CD. In addition, we will address the role of diet as an essential external factor modulating microbiome changes, potentially underlying disease initiation and development.

Comparison of the gut microbiota of short-term and long-term medical workers and non-medical controls: a cross-sectional analysis

OBJECTIVES

The hospital environment has been implicated in the enrichment and exchange of pathogens and antibiotic resistance, but its potential in shaping the symbiotic microbial community of hospital staff is unclear. This study was designed to evaluate the alteration of the gut microbiome in medical workers compared to non-medical controls.

METHODS

A prospective cross-sectional cohort study was conducted in the intensive care unit (ICU) and other departments of a centre in north-eastern China. Faecal samples of 175 healthy medical workers-short-term (1-3 months) workers (n = 80) and long-term (>1 year) workers (n = 95)-and 80 healthy non-medical controls were analysed using 16S rRNA amplicon sequencing. The hospital environmental samples (n = 9) were also analysed.

RESULTS

The gut microbiomes of medical workers exhibited marked deviations in diversity and alteration in microbial composition and function. Short-term workers showed significantly higher abundances of taxa such as Lactobacillus, Butyrivibrio, Clostridiaceae, Clostridium, Ruminococcus, Dialister, Bifidobacterium, Odoribacter, and Desulfovibrio and lower abundances of Bacteroides and Blautia than the controls. Long-term workers showed higher abundances of taxa such as Dialister, Veillonella, Clostridiaceae, Clostridium, Bilophila, Desulfovibrio, Pseudomonas, and Akkermansia and lower abundances of Bacteroides and Coprococcus than the controls. The medical workers' department (ICU versus non-ICU) and position (resident doctor versus nursing staff) also impacted their gut microbiome. Compared with the non-ICU workers, workers in the ICU showed a significant increase in the abundances of Dialister, Enterobacteriaceae, Phascolarctobacterium, Pseudomonas, Veillonella, and Streptococcus and a marked depletion of Faecalibacterium, Blautia, and Coprococcus. In contrast with the nursing staff, the resident doctors showed a significant increase in Erysipelotrichaceae and Clostridium and a decrease in Bacteroides, Blautia, and Ruminococcus in the gut microbiome. Moreover, we found that the microbiota of hospital environments potentially correlated with the workers' gut microbiota.

CONCLUSIONS

Our findings demonstrated structural changes in the gut microbial community of medical workers.

Long-term exposure of high concentration heavy metals induced toxicity, fatality, and gut microbial dysbiosis in common carp, Cyprinus carpio

Heavy metals (HMs) in an aquatic environment mainly affects fish, and thus, fish are convenient pollution bio-indicators. In this study, the toxic effects of HM mixture (chromium (Cr), cadmium (Cd), copper (Cu)) in 0 mg/L to 3.2 mg/L concentration range was investigated in Cyprinus carpio (28 days). HM accumulation, histopathology, oxidative stress, and gut microbial changes were evaluated. HMs accumulated in the order of Cr > Cu > Cd, primarily in the kidneys and finally scales. Reactive oxygen species generation increased in all exposure groups up to day 14, with maximum generation at 3.2 mg/L mixture, which later decreased on day 28 in all. Malondialdehydeand and superoxide dismutase levels increased from day 7 to 28 with increased HM concentrations, while total protein showed an inverse trend. Gill histopathology showed major changes such as uplifted and disintegrated primary lamella, and secondary lamella shortening. The kidneys were characterized by glomerular necrosis, Bowman's capsule expansion, and tubular space dilatation. Proteobacteria and Firmicutes abundance increased up to 59.4% and 99.16% in 0.8 mg/L and 3.2 mg/L treatment groups, respectively. This study provided a better understanding on the physiology and gut microbiota alteration in C. carpio under multiple HM stress.

Significance of human microbiome in breast cancer: Tale of an invisible and an invincible

The human microbiome is a mysterious treasure of the body playing endless important roles in the well-being of the host metabolism, digestion, and immunity. On the other hand, it actively participates in the development of a variety of pathological conditions including cancer. With the Human Microbiome Project initiative, metagenomics, and next-generation sequencing technologies in place, the last decade has witnessed immense explorations and investigations on the enigmatic association of breast cancer with the human microbiome. However, the connection between the human microbiome and breast cancer remains to be explored in greater detail. In fact, there are several emerging questions such as whether the host microbiota contributes to disease initiation, or is it a consequence of the disease is an irrevocably important question that demands a valid answer. Since the microbiome is an extremely complex community, gaps still remain on how this vital microbial organ plays a role in orchestrating breast cancer development. Nevertheless, undeniable evidence from studies has pinpointed the presence of specific microbial elements of the breast and gut to play a role in governing breast cancer. It is still unclear if an alteration in microbiome/dysbiosis leads to breast cancer or is it vice versa. Though specific microbial signatures have been detected to be associated with various breast cancer subtypes, the structure and composition of a core "healthy" microbiome is yet to be established. Probiotics seem to be a promising antidote for targeted prevention and treatment of breast cancer. Interestingly, these microbial communities can serve as potential biomarkers for prognosis, diagnosis, and treatment of breast cancer, thereby leading to the rise of a completely new era of personalized medicine. This review is a humble attempt to summarize the research findings on the human microbiome and its relation to breast cancer.

Porcine circovirus type 2 (PCV2) and Campylobacter infection induce diarrhea in piglets: Microbial dysbiosis and intestinal disorder

Diarrhea is considered to be associated with microbial dysbiosis caused by infection of pathogens but poorly understood. We herein characterized the colonic microbiota of diarrheal early-weaning piglets infected with porcine circovirus type 2 (PCV2) and Campylobacter. Campylobacter infection significantly decreased species richness and Shannon diversity index of colonic microbiota together with a significant increase in the proportion of Campylobacter and Enterobacteriaceae, whereas no significant difference on the above indexes was observed in piglets infected with PCV2 compared with healthy piglets. PCV2 and Campylobacter infection could disturb the homeostasis of colonic microbiota through deterioration of ecological network within microbial community, and specially Campylobacter performed as a module hub in ecological networks. The microbial dysbiosis caused metabolic dysfunction and led to a remarkable reduction in production of short chain fatty acids, following by a higher pH level in colon cavity. Campylobacter infection disturbed the function of colonic tract barrier observed in terms of significant lower relative expression of claudin-1, occluding, and zonula occludens protein-1 genes, and PCV2 infection induced intestinal inflammation together with a higher permeability of colon. Generally, these results suggested that PCV2 and Campylobacter infection could induce microbial dysbiosis and metabolic dysfunction, and cause intestinal disorder, all of which finally were associated to contribute to the diarrhea of early-weaning piglets.

MicroRNAs and microbiota: Is there a cross talk?

MicroRNAs (miRNAs) are a form of single-stranded RNA molecules with a length that varies between 18 and 23 nucleotides and which are synthesized in the nucleus but function in the cytoplasm. miRNAs function endogenously and bind to complementary sequences in either the coding regions or the 3' untranslated regions (UTRs) of target messenger RNAs (mRNAs). This indicates that miRNAs operate in a post-transcriptional manner. miRNAs play essential roles in various biological events, and have thus been found extracellularly in different body fluids such as saliva, urine and plasma. miRNAs are distinguished in the gut mainly by examining content from intestines and feces. The gastrointestinal tract is infested with a variety of microorganisms that are initially inherited from the mother; however, those microorganisms develop as a result of changes in dietary intakes and environmental factors. The gut microbiota are therefore shaped differently in different individuals due to several contributing factors such as genetics, diet and state of disease, and have a great impact on the host during phases of disease and homeostasis.

Domestic canines do not display evidence of gut microbial dysbiosis in the presence of Clostridioides (Clostridium) difficile, despite cellular susceptibility to its toxins

Clostridioides difficile infection (CDI) is an emerging public health threat and C. difficile is the most common cause of antimicrobial-associated diarrhea worldwide and the leading cause of hospital-associated infections in the US, yet the burden of community-acquired infections (CAI) is poorly understood. Characterizing C. difficile isolated from canines is important for understanding the role that canines may play in CAI. In addition, several studies have suggested that canines carry toxigenic C. difficile asymptomatically, which may imply that there are mechanisms responsible for resistance to CDI in canines that could be exploited to help combat human CDI. To assess the virulence potential of canine-derived C. difficile, we tested whether toxins TcdA and TcdB (hereafter toxins) derived from a canine isolate were capable of causing tight junction disruptions to colonic epithelial cells. Additionally, we addressed whether major differences exist between human and canine cells regarding C. difficile pathogenicity by exposing them to identical toxins. We then examined the canine gut microbiome associated with C. difficile carriage using 16S rRNA gene sequencing and searched for deviations from homeostasis as an indicator of CDI. Finally, we queried 16S rRNA gene sequences for bacterial taxa that may be associated with resistance to CDI in canines. Clostridioides difficile isolated from a canine produced toxins that reduced tight junction integrity in both human and canine cells in vitro. However, canine guts were not dysbiotic in the presence of C. difficile. These findings support asymptomatic carriage in canines and, furthermore, suggest that there are features of the gut microbiome and/or a canine-specific immune response that may protect canines against CDI. We identified two biologically relevant bacteria that may aid in CDI resistance in canines: 1) Clostridium hiranonis, which synthesizes secondary bile acids that have been shown to provide resistance to CDI in mice; and 2) Sphingobacterium faecium, which produces sphingophospholipids that may be associated with regulating homeostasis in the canine gut. Our findings suggest that canines may be cryptic reservoirs for C. difficile and, furthermore, that mechanisms of CDI resistance in the canine gut could provide insights into targeted therapeutics for human CDI.

Relationship between intestinal microbial dysbiosis and primary liver cancer

BACKGROUND

Intestinal microbial dysbiosis is involved in liver disease pathogenesis. However, its role in primary liver cancer (PLC), particularly in hepatocarcinogenesis remains unclear. The present study aimed to study the changes in intestinal flora at various stages of PLC and clarify the relationship between intestinal microbes and PLC.

METHODS

Twenty-four patients with PLC (PLC group), 24 patients with liver cirrhosis (LC group), and 23 healthy control individuals (HC group) were enrolled from October 2016 to October 2017. Stool specimens of the participants were collected and the genomic DNA of fecal bacteria was isolated. High-throughput pyrosequencing of 16S rDNA was used to identify differences in gut bacterial diversity among HC, LC, and PLC groups. We also analyzed the relationship between clinical factors and intestinal microorganisms in LC and PLC groups.

RESULTS

Diversity of Firmicutes tended to decrease from the HC to LC and PLC groups at the phylum level. Among species, Enterobacter ludwigii displayed an increasing trend in the PLC group, wherein the relative abundance of Enterobacter ludwigii in the PLC group was 100 times greater than that in the HC and LC groups. The ratio of Firmicutes/Bacteroidetes was significantly decreased with the disease progression. In addition, the linear discriminant analysis effect size method indicated that Clostridia were predominant in the gut microbiota of the HC group, whereas Enterococcaceae, Lactobacillales, Bacilli and Gammaproteobacteria may be used as diagnostic markers of PLC. Redundancy analysis showed a correlation between intestinal microbial diversity and clinical factors AST, ALT, and AFP. Veillonella showed a significant positive correlation with AFP in the PLC group, whereas Subdoligranulum showed a negative correlation with AFP.

CONCLUSIONS

This study indicates that dysbiosis of the gut microbiota might be involved in PLC development and progression.

Helicobacter pylori Infection, the Gastric Microbiome and Gastric Cancer

After a long period during which the stomach was considered as an organ where microorganisms could not thrive, Helicobacter pylori was isolated in vitro from gastric biopsies, revolutionising the fields of Microbiology and Gastroenterology. Since then, and with the introduction of high-throughput sequencing technologies that allowed deep characterization of microbial communities, a growing body of knowledge has shown that the stomach contains a diverse microbial community, which is different from that of the oral cavity and of the intestine. Gastric cancer is a heterogeneous disease that is the end result of a cascade of events arising in a small fraction of patients colonized with H. pylori. In addition to H. pylori infection and to multiple host and environmental factors that influence disease development, alterations to the composition and function of the normal gastric microbiome, also known as dysbiosis, may also contribute to malignancy. Chronic inflammation of the mucosa in response to H. pylori may alter the gastric environment, paving the way to the growth of a dysbiotic gastric bacterial community. This dysbiotic microbiome may promote the development of gastric cancer by sustaining inflammation and/or inducing genotoxicity. This chapter summarizes what is known about the gastric microbiome in the context of H. pylori-associated gastric cancer, introducing the emerging dimension of the microbiome into the pathogenesis of this highly incident and deadly disease.

Role of the Gut Microbiome in Autism Spectrum Disorders

Autism spectrum disorder (ASD) is a severe neurodevelopmental or neuropsychiatric disorder with elusive etiology and obscure pathophysiology. Cognitive inabilities, impaired communication, repetitive behavior pattern, and restricted social interaction and communication lead to a debilitating situation in autism. The pattern of co-occurrence of medical comorbidities is most intriguing in autism, compared to any other neurodevelopmental disorders. They have an elevated comorbidity burden among which most frequently are seizures, psychiatric illness, and gastrointestinal disorders. The gut microbiota is believed to play a pivotal role in human health and disease through involvement in physiological homoeostasis, immunological development, glutathione metabolism, amino acid metabolism, etc., which in a reasonable way explain the role of gut-brain axis in autism. Branded as a neurodevelopmental disorder with psychiatric impairment and often misclassified as a mental disorder, many experts in the field think that a therapeutic solution to autism is unlikely to emerge. As the pathophysiology is still elusive, taking into account of the various symptoms that are concurrent in autism is important. Gastrointestinal problems that are seen associated with most of the autism cases suggest that it is not just a psychiatric disorder as many claim but have a physiological base, and alleviating the gastrointestinal problems could help alleviating the symptoms by bringing out the much needed overall improvement in the affected victims. A gut disorder akin to Crohn's disease is, sometimes, reported in autistic children, an extremely painful gastrointestinal disease which is named as autistic enterocolitis. This disturbed situation hypothesized to be initiated by dysbiosis or microbial imbalance could in turn perturb the coordination of microbiota-gut-brain axis which is important in human mental health as goes the popular dictum: "fix your gut, fix your brain."

Dysbiosis in Children Born by Caesarean Section

The rate of Caesarean-section delivery in the United States has increased by 60% from 1996 through to 2013 and now accounts for > 30% of births [CDC, 2017]. The purpose of this review is to present the current understanding of both the microbial risk factors that increase the likelihood of a Caesarean-section delivery and the microbial dysbiosis that is thought to result from the Caesarean section. We provide examples of research into the impact of early-life microbial dysbiosis on infant development and long-term health outcomes, as well as consider the efficacy and the long-term implications of microbiome-based therapies to mitigate this dysbiosis. The steep rise in the Caesarean-section delivery rate makes it imperative to understand the potential of microbiota modulation for the treatment of dysbiosis.

Speculation as to why the Frequency of Eosinophilic Esophagitis Is Increasing

PURPOSE OF REVIEW

The frequency of eosinophilic esophagitis (EoE), an immune/antigen-mediated disorder first described in 1993, has been increasing rapidly. The purpose of this review is to consider hypotheses proposed to explain this increase and to speculate on their validity.

RECENT FINDINGS

The hygiene hypothesis attributes the rise of EoE to modern hygienic conditions resulting in fewer childhood infections with microbes that might have protected against allergy development. Microbial dysbiosis, a change in the microbiome's composition and diversity caused by a modern affluent lifestyle, also might contribute to allergic conditions. Environmental factors including modern chemicals contaminating crops, livestock treated with hormones and antibiotics, food additives and processing changes, and pollutants in the air and water conceivably might predispose to EoE. One intriguing hypothesis attributes increasing EoE to increasing use of acid-suppressive medications like proton pump inhibitors, which might prevent peptic digestion of food allergens, increase gastric permeability, and alter the microbiome to favor food allergy development. In a recent pediatric case-control study, use of acid suppressants in infancy was by far the single strongest risk factor identified for later development of EoE. It remains unclear which, if any, of the above factors underlies the rising frequency of EoE. These factors need not be mutually exclusive, and the cause of EoE may well be multifactorial.

Speculation as to why the Frequency of Eosinophilic Esophagitis Is Increasing. Curr Gastroenterol Rep. 2018;20:26. [PMID: 29767340 DOI: 10.1007/s11894-018-]

PURPOSE OF REVIEW

The frequency of eosinophilic esophagitis (EoE), an immune/antigen-mediated disorder first described in 1993, has been increasing rapidly. The purpose of this review is to consider hypotheses proposed to explain this increase and to speculate on their validity.

RECENT FINDINGS

The hygiene hypothesis attributes the rise of EoE to modern hygienic conditions resulting in fewer childhood infections with microbes that might have protected against allergy development. Microbial dysbiosis, a change in the microbiome's composition and diversity caused by a modern affluent lifestyle, also might contribute to allergic conditions. Environmental factors including modern chemicals contaminating crops, livestock treated with hormones and antibiotics, food additives and processing changes, and pollutants in the air and water conceivably might predispose to EoE. One intriguing hypothesis attributes increasing EoE to increasing use of acid-suppressive medications like proton pump inhibitors, which might prevent peptic digestion of food allergens, increase gastric permeability, and alter the microbiome to favor food allergy development. In a recent pediatric case-control study, use of acid suppressants in infancy was by far the single strongest risk factor identified for later development of EoE. It remains unclear which, if any, of the above factors underlies the rising frequency of EoE. These factors need not be mutually exclusive, and the cause of EoE may well be multifactorial.

Neuroprotective effects of fecal microbiota transplantation on MPTP-induced Parkinson's disease mice: Gut microbiota, glial reaction and TLR4/TNF-α signaling pathway

Parkinson's disease (PD) patients display alterations in gut microbiota composition. However, mechanism between gut microbial dysbiosis and pathogenesis of PD remains unexplored, and no recognized therapies are available to halt or slow progression of PD. Here we identified that gut microbiota from PD mice induced motor impairment and striatal neurotransmitter decrease on normal mice. Sequencing of 16S rRNA revealed that phylum Firmicutes and order Clostridiales decreased, while phylum Proteobacteria, order Turicibacterales and Enterobacteriales increased in fecal samples of PD mice, along with increased fecal short-chain fatty acids (SCFAs). Remarkably, fecal microbiota transplantation (FMT) reduced gut microbial dysbiosis, decreased fecal SCFAs, alleviated physical impairment, and increased striatal DA and 5-HT content of PD mice. Further, FMT reduced the activation of microglia and astrocytes in the substantia nigra, and reduced expression of TLR4/TNF-α signaling pathway components in gut and brain. Our study demonstrates that gut microbial dysbiosis is involved in PD pathogenesis, and FMT can protect PD mice by suppressing neuroinflammation and reducing TLR4/TNF-α signaling.

Fecal microbial dysbiosis in Chinese patients with inflammatory bowel disease

AIM

To analyze the alterations of fecal microbiota in Chinese patients with inflammatory bowel disease (IBD).

METHODS

Fecal samples from 15 patients with Crohn’s disease (CD) (11 active CD, 4 inactive CD), 14 patients with active ulcerative colitis (UC) and 13 healthy individuals were collected and subjected to 16S ribosomal DNA (rDNA) gene sequencing. The V4 hypervariable regions of 16S rDNA gene were amplified from all samples and sequenced by the Illumina MiSeq platform. Quality control and operational taxonomic units classification of reads were calculated with QIIME software. Alpha diversity and beta diversity were displayed with R software.

RESULTS

Community richness (chao) and microbial structure in both CD and UC were significantly different from those in normal controls. At the phyla level, analysis of the microbial compositions revealed a significantly greater abundance of Proteobacteria in IBD as compared to that in controls. At the genera level, 8 genera in CD and 23 genera in UC (in particular, the Escherichia genus) showed significantly greater abundance as compared to that in normal controls. The relative abundance of Bacteroidetes in the active CD group was markedly lower than that in the inactive CD group. The abundance of Proteobacteria in patients with active CD was nominally higher than that in patients with inactive CD; however, the difference was not statistically significant after correction. Furthermore, the relative abundance of Bacteroidetes showed a negative correlation with the CD activity index scores.

CONCLUSION

Our study profiles specific characteristics and microbial dysbiosis in the gut of Chinese patients with IBD. Bacteroidetes may have a negative impact on inflammatory development.

Therapy of Sinonasal Microbiome in CRS: A Critical Approach

PURPOSE OF REVIEW

Perturbations in local microbiota have been demonstrated in many chronic inflammatory diseases including chronic rhinosinusitis (CRS). The purpose of this paper is to review the latest microbiome research as it pertains to CRS and establish whether there is any evidence supporting the microbiome hypothesis for CRS. Treatment factors that may influence the sinonasal microbiome as well as the role of probiotics are also discussed.

RECENT FINDINGS

Despite significant heterogeneity in study design, tissue sampling, processing and bioinformatics analysis, consistent findings have emerged from the recent literature. Healthy individuals and CRS patients have similar overall bacterial burden of disease and share many common phylum. CRS patients, however, routinely show reductions in markers of biodiversity. Both medical and surgical treatments appear to influence the sinonasal microbiome, with certain bacterial strains associated with better treatment outcomes. The presence of microbial dysbiosis in CRS is now supported by numerous studies. Whether this dysbiosis is a cause or rather an association of the disease process still remains unclear. Although probiotic therapies show early promise, much larger studies are required to establish their real role as a treatment for CRS.

Airway Microbiota and the Implications of Dysbiosis in Asthma

The mucosal surfaces of the human body are typically colonized by polymicrobial communities seeded in infancy and are continuously shaped by environmental exposures. These communities interact with the mucosal immune system to maintain homeostasis in health, but perturbations in their composition and function are associated with lower airway diseases, including asthma, a developmental and heterogeneous chronic disease with various degrees and types of airway inflammation. This review will summarize recent studies examining airway microbiota dysbioses associated with asthma and their relationship with the pathophysiology of this disease.

Relationship between gastrointestinal micro-ecological imbalance and development of gastric cancer

The human body and microorganisms present in the body form a symbiotic system as the relationship between eukaryotes and prokaryotes. Therefore, it is not enough to study human diseases only in terms of human body. Recent studies have pointed out that microorganisms are involved in the occurrence of a large number of malignant tumors. According to a conservative estimate, at least 15% of cancer cases are associated with infectious agents. Gastric cancer is the second major cause of global cancer deaths. For a long period of time, researchers believe that Helicobacter pylori associated with chronic gastritis is the strongest risk factor for the occurrence of gastric cancer. However, with the progress of molecular biology research, it has been found that there is a close interaction between the large microbial flora and Helicobacter pylori in the gastrointestinal tract. The changes of microbial community composition have important effects on the formation, development and intervention of gastric cancer. This article will review the occurrence and development of gastrointestinal microorganism and gastric cancer.

Intestinal microbiota in inflammatory bowel disease: Friend of foe?

Inflammatory bowel disease (IBD) arises from disruption of immune tolerance to the gut commensal microbiota, leading to chronic intestinal inflammation and mucosal damage in genetically predisposed hosts. In healthy individuals the intestinal microbiota have a symbiotic relationship with the host organism and possess important and unique functions, including a metabolic function (i.e. digestion of dietary compounds and xenobiotics, fermentation of undigestible carbohydrates with production of short chain fatty acids), a mucosal barrier function (i.e. by inhibiting pathogen invasion and strengthening epithelial barrier integrity), and an immune modulatory function (i.e. mucosal immune system priming and maintenance of intestinal epithelium homeostasis). A fine balance regulates the mechanism that allows coexistence of mammals with their commensal bacteria. In IBD this mechanism of immune tolerance is impaired because of several potential causative factors. The gut microbiota composition and activity of IBD patients are abnormal, with a decreased prevalence of dominant members of the human commensal microbiota (i.e. Clostridium IXa and IV groups, Bacteroides, bifidobacteria) and a concomitant increase in detrimental bacteria (i.e. sulphate-reducing bacteria, Escherichia coli). The observed dysbiosis is concomitant with defective innate immunity and bacterial killing (i.e. reduced mucosal defensins and IgA, malfunctioning phagocytosis) and overaggressive adaptive immune response (due to ineffective regulatory T cells and antigen presenting cells), which are considered the basis of IBD pathogenesis. However, we still do not know how the interplay between these parameters causes the disease. Studies looking at gut microbial composition, epithelial integrity and mucosal immune markers in genotyped IBD populations are therefore warranted to shed light on this obscure pathogenesis.