Perturbations of the gut microbiome in anti-CCP positive individuals at risk of developing rheumatoid arthritis

High fat diet increases the severity of collagen-induced arthritis in mice by altering the gut microbial community

OBJECTIVES

Research has demonstrated that obesity may be associated with rheumatoid arthritis (RA). In addition, gut microbiota and its metabolites contribute to the occurrence and development of RA and obesity. However, the mechanism by which obesity affects RA remains unclear. In this study, we aimed to investigate whether gut microbiota and their metabolites alter the effects of high fat diet (HFD) on the severity of collagen-induced arthritis (CIA) in mice.

METHODS

Briefly, mice were divided into normal group (N), CIA model group (C), HFD group (T), and HFD CIA group (CT). Hematoxylin and Eosin staining(HE) and Safranin O-fast green staining were conducted, and levels of blood lipid and inflammatory cytokines were measured. 16S rDNA sequencing technique and liquid chromatography-mass spectrometry (LC-MS)-based metabolomics were performed to explore changes in the microbiota structure to further reveal the pathomechanism of HFD on CIA.

RESULTS

HFD aggravated the severity of CIA in mice. The CT group had the highest proportion of microbial abundance of Blautia, Oscillibacter, Ruminiclostridium-9, and Lachnospiraceae UCG 006 at the genus level, but had a lower proportion of Alistipes. Additionally, the fecal metabolic phenotype of the combined CT group shows significant changes, with differential metabolites enriched in 9 metabolic pathways, including primary bile acid biosynthesis, arginine biosynthesis, sphingolipid metabolism, purine metabolism, linoleic acid metabolism, oxytocin signaling pathway, aminoacyl-tRNA biosynthesis, the pentose phosphate pathway, and sphingolipid signaling pathway. Correlation analysis revealed that some of the altered gut microbiota genera were strongly correlated with changes in fecal metabolites, total cholesterol (TC), triglyceride (TG), and inflammatory cytokine levels.

CONCLUSIONS

This study shows that HFD may aggravate inflammatory reaction in CIA mice by altering the gut microbiota and metabolic pathways.

Synergistic effect of chitosan and β-carotene in inhibiting MNU-induced retinitis pigmentosa

In this study, N-Methyl-N-nitrosourea (MNU) was intraperitoneally injected to construct a mouse retinitis pigmentosa (RP) model to evaluate the protective effect of chitosan and β-carotene on RP. The results demonstrated that chitosan synergized with β-carotene significantly reduced retinal histopathological structural damage in RP mice. The co-treatment group of β-carotene and chitosan restored the retinal thickness and outer nuclear layer thickness better than the group treated with the two alone, and the thickness reached the normal level. The content of β-carotene and retinoids in the liver of chitosan and β-carotene co-treated group increased by 46.75 % and 20.69 %, respectively, compared to the β-carotene group. Chitosan and β-carotene supplement suppressed the expressions of Bax, Calpain2, Caspase3, NF-κB, TNF-α, IL-6, and IL-1β, and promoted the up-regulation of Bcl2. Chitosan and β-carotene interventions remarkably contributed to the content of SCFAs and enhanced the abundance of Ruminococcaceae, Rikenellaceae, Odoribacteraceae and Helicobacteraceae. Correlation analysis demonstrated a strong association between gut microbiota and improvement in retinitis pigmentosa. This study will provide a reference for the study of the gut-eye axis.

Rheumatoid arthritis and the intestinal microbiome: probiotics as a potential therapy

Rheumatoid arthritis (RA) is a systemic autoimmune disorder characterized by swollen joints, discomfort, stiffness, osteoporosis, and reduced functionality. Genetics, smoking, dust inhalation, high BMI, and hormonal and gut microbiota dysbiosis are all likely causes of the onset or development of RA, but the underlying mechanism remains unknown. Compared to healthy controls, patients with RA have a significantly different composition of gut microbiota. It is well known that the human gut microbiota plays a key role in the initiation, maintenance, and operation of the host immune system. Gut microbiota dysbiosis has local or systematic adverse effects on the host immune system, resulting in host susceptibility to various diseases, including RA. Studies on the intestinal microbiota modulation and immunomodulatory properties of probiotics have been reported, in order to identify their potential possibility in prevention and disease activity control of RA. This review summarized current studies on the role and potential mechanisms of gut microbiota in the development and progression of RA, as well as the preventative and therapeutic effects and potential mechanisms of probiotics on RA. Additionally, we proposed the challenges and difficulties in the application of probiotics in RA, providing the direction for the research and application of probiotics in the prevention of RA.

Integrative non-pharmacological care for individuals at risk of rheumatoid arthritis

There is increasing knowledge in the recognition of individuals at risk for progression to rheumatoid arthritis (RA) before the clinical manifestation of the disease. This prodromal phase preceding the manifestation of RA may represent a "window of opportunity" for preventive interventions that may transform the clinical approach to this disease. However, limited evidence exists in support of effective interventions to delay the onset or even halt the manifestation of RA. Given the multifactorial nature of RA development and disease progression, the latest guidelines for established RA stress the use of integrative interventions and multidisciplinary care strategies, combining pharmacologic treatment with non-pharmacological approaches. Accordingly, individuals at risk of RA could be offered an integrative, multifactorial intervention approach. Current data point toward pharmacological intervention reverting the subclinical inflammation and delay in the disease onset. In addition, targeting life style modifiable factors (smoking cessation, dental health, physical activity, and diet) may presumably improve RA prognosis in individuals at risk, mainly by changes in epigenetics, autoantibodies, cytokines profiles, and microbiome. Nonetheless, the benefits of multidisciplinary interventions to halt the manifestation of RA in at-risk individuals remain unknown. As there is a growing knowledge of possible pharmacological intervention in the preclinical phase, this narrative review aims to provide a comprehensive overview of non-pharmacological treatments in individuals at risk of RA. Considering the mechanisms preceding the clinical manifestation of RA we explored all aspects that would be worth modifying and that would represent an integrative non-pharmacological care for individuals at risk of RA.

'What is my risk really?': a qualitative exploration of preventive interventions among individuals at risk of rheumatoid arthritis

Objectives

Intervention in the pre-arthritis phase of RA could prevent or delay the onset of disease. The primary aim of this study was to explore perspectives of being at risk and potential preventive interventions among individuals at risk of developing RA and to identify factors influencing their engagement with prevention. A secondary aim, established during the analytical process, was to understand and compare different approaches to health-related behaviours related to prevention of RA.

Methods

Anti-CCP-positive (CCP+) at-risk individuals with musculoskeletal symptoms but no synovitis participated in semi-structured interviews. Data were analysed using reflexive thematic analysis, followed by a secondary ideal-type analysis.

Results

Nineteen CCP+ at-risk individuals (10 women; age range 35-70 years) participated. Three overarching themes were identified: being CCP+ at risk; aiming to prevent RA; and influencers of engagement. Participants described distress related to symptoms and uncertainty about disease progression. Many participants had concerns about medication side effects. In contrast, most participants expressed willingness to make lifestyle changes with the aim of preventing RA. Engagement with preventive measures was influenced by symptom severity, personal risk level, co-morbidities, experiences of taking other medications/supplements, knowledge of RA, risk factors and medications, and perceived effort. Three types of participants were identified from the data: proactive preventers, change considerers and fearful avoiders. Overall orientation to health behaviours also impacted the attitude towards preventing RA.

Conclusion

Findings could inform recruitment and retention in RA prevention research and promote uptake of preventive interventions in clinical practice.

Elevated Serum Levels of Zonulin Family Peptides in Anticitrullinated Protein Antibody-Positive At-Risk Individuals Without Arthritis

OBJECTIVE

Recent advances imply that early events triggering rheumatoid arthritis (RA) occur at mucosal surfaces. We aimed to evaluate whether intestinal permeability is altered in patients at increased risk of RA, and/or predicts the development of clinical arthritis, by measuring serum zonulin family peptides (ZFP) levels, which are shown to reflect intestinal barrier integrity.

METHODS

Two independent prospective observational cohorts were studied, including subjects with musculoskeletal symptoms and anticitrullinated protein antibodies (ACPA), but without clinical arthritis at baseline. In Sweden, 82 such at-risk patients were compared to 100 age-matched healthy blood donors. In the UK, 307 at-risk patients were compared to 100 ACPA-negative symptomatic controls. ZFP was measured in baseline sera by enzyme-linked immunoassays.

RESULTS

In the Swedish at-risk cohort, ZFP levels were significantly increased in patients compared to controls (mean 41.4 vs 33.6 ng/mL, P < 0.001) and Cox regression analysis showed prognostic value of ZFP for arthritis development (hazard ratio [HZ] 1.04 per ng/mL ZFP increase, 95% CI 1.01-1.07, P = 0.02). Elevated ZFP levels among ACPA-positive at-risk patients compared to symptomatic ACPA-negative controls were confirmed in the UK at-risk cohort (mean 69.7 vs 36.0 ng/mL, P < 0.001), but baseline ZFP were not associated with arthritis development (HR 1.00 per ng/mL ZFP increase, 95% CI 1.00-1.01, P = 0.30).

CONCLUSION

Serum ZFP levels are elevated in ACPA-positive at-risk patients when compared to both healthy blood donors and symptomatic ACPA-negative controls. Thus, gut barrier function may be of importance in RA-associated autoimmunity. A possible prognostic value of serum ZFP merits further investigation, preferably in larger prospective cohorts.

Gut microbiome and intestinal inflammation in preclinical stages of rheumatoid arthritis

BACKGROUND

Faecal Prevotellaceae, and other microbes, have been associated with rheumatoid arthritis (RA) and preclinical RA. We have performed a quantitative microbiome profiling study in preclinical stages of RA.

METHODS

First-degree relatives of patients with RA (RA-FDRs) from the SCREEN-RA cohort were categorised into four groups: controls, healthy asymptomatic RA-FDRs; high genetic risk, asymptomatic RA-FDRs with two copies of the shared epitope; autoimmunity, asymptomatic RA-FDRs with RA-associated autoimmunity; and symptomatic, clinically suspect arthralgias or untreated new-onset RA.Faecal samples were collected and frozen. 16S sequencing was performed, processed with DADA2 pipeline and Silva database. Cell counts (cytometry) and faecal calprotectin (enzyme-linked immunosorbent assay, ELISA) were also obtained. Microbial community analyses were conducted using non-parametric tests, such as permutational multivariate analysis of variance (PERMANOVA), Wilcoxon and Kruskal-Wallis, or Aldex2.

RESULTS

A total of 371 individuals were included and categorised according to their preclinical stage of the disease. Groups had similar age, gender and body mass index. We found no significant differences in the quantitative microbiome profiles by preclinical stages (PERMANOVA, R2=0.00798, p=0.56) and, in particular, no group differences in Prevotellaceae abundance. Results were similar when using relative microbiome profiling data (PERMANOVA, R2=0.0073, p=0.83) or Aldex2 on 16S sequence counts. Regarding faecal calprotectin, we found no differences between groups (p=0.3).

CONCLUSIONS

We could not identify microbiome profiles associated with preclinical stages of RA. Only in a subgroup of individuals with the most pronounced phenotypes did we modestly retrieve the previously reported associations.

Microbiota-dependent indole production stimulates the development of collagen-induced arthritis in mice

Altered tryptophan catabolism has been identified in inflammatory diseases like rheumatoid arthritis (RA) and spondyloarthritis (SpA), but the causal mechanisms linking tryptophan metabolites to disease are unknown. Using the collagen-induced arthritis (CIA) model, we identified alterations in tryptophan metabolism, and specifically indole, that correlated with disease. We demonstrated that both bacteria and dietary tryptophan were required for disease and that indole supplementation was sufficient to induce disease in their absence. When mice with CIA on a low-tryptophan diet were supplemented with indole, we observed significant increases in serum IL-6, TNF, and IL-1β; splenic RORγt+CD4+ T cells and ex vivo collagen-stimulated IL-17 production; and a pattern of anti-collagen antibody isotype switching and glycosylation that corresponded with increased complement fixation. IL-23 neutralization reduced disease severity in indole-induced CIA. Finally, exposure of human colonic lymphocytes to indole increased the expression of genes involved in IL-17 signaling and plasma cell activation. Altogether, we propose a mechanism by which intestinal dysbiosis during inflammatory arthritis results in altered tryptophan catabolism, leading to indole stimulation of arthritis development. Blockade of indole generation may present a unique therapeutic pathway for RA and SpA.

Gut microbiota in pre-clinical rheumatoid arthritis: From pathogenesis to preventing progression

Rheumatoid arthritis (RA) is a chronic autoimmune disease characterized by progressive polyarthritis that leads to cartilage and bone damage. Pre-clinical RA is a prolonged state before clinical arthritis and RA develop, in which autoantibodies (antibodies against citrullinated proteins, rheumatoid factors) can be present due to the breakdown of immunologic self-tolerance. As early treatment initiation before the onset of polyarthritis may achieve sustained remission, optimize clinical outcomes, and even prevent RA progression, the pre-clinical RA stage is showing the prospect to be the window of opportunity for RA treatment. Growing evidence has shown the role of the gut microbiota in inducing systemic inflammation and polyarthritis via multiple mechanisms, which may involve molecular mimicry, impaired intestinal barrier function, gut microbiota-derived metabolites mediated immune regulation, modulation of the gut microbiota's effect on immune cells, intestinal epithelial cells autophagy, and the interaction between the microbiome and human leukocyte antigen alleles as well as microRNAs. Since gut microbiota alterations in pre-clinical RA have been reported, potential therapies for modifying the gut microbiota in pre-clinical RA, including natural products, antibiotic therapy, fecal microbiota transplantation, probiotics, microRNAs therapy, vitamin D supplementation, autophagy inducer-based treatment, prebiotics, and diet, holds great promise for the successful treatment and even prevention of RA via altering ongoing inflammation. In this review, we summarized current studies that include pathogenesis of gut microbiota in RA progression and promising therapeutic strategies to provide novel ideas for the management of pre-clinical RA and possibly preventing arthritis progression.

Time-varying risks of infection in patients as they proceed through the phases of 'pre-RA': results from the Scottish Early RA inception cohort

ObjectiveRheumatoid arthritis (RA) develops after progressing through sequential 'pre-RA' phases. The mechanisms driving progression from one phase to the next remain poorly understood. This study examined the longitudinal rates of community and hospital infections in patients during sequential stages of pre-RA and early arthritis.

METHODS

The Scottish Early RA inception cohort recruited patients with newly diagnosed RA. Incidences of infection were determined from community antibiotic prescriptions and serious infections were determined by hospital discharge coding. Dates of diagnosis and symptom onset allowed identification of asymptomatic/symptomatic pre-RA and early arthritis eras to analyse infection rates over time compared with age- and sex-matched controls.

RESULTS

The incidence rate ratio (IRR) seen in the period 0-6 months prior to symptom onset was 1.28 (95% CI 1.15 to 1.42). In 'symptomatic pre-RA', the IRR was 1.33 (95% CI 1.18 to 1.49) which persisted into 'early arthritis'. The rate of hospital admissions was numerically greater in 'pre-RA' and significantly greater in 'early arthritis' (IRR 1.82, 95% CI 1.32 to 2.46).

CONCLUSION

Antibiotic risk is increased in patients with 'pre-RA' at least 6 months before symptoms develop, and this persists throughout the symptomatic pre-RA phase. Infections may be important in the mechanisms that drive progression to RA or be a manifestation of immune dysfunction (or both). These observations could inform safety and efficacy considerations for interventions in pre-RA to prevent progression. Patients with 'pre-RA' with recurrent antibiotic use may also be an identifiable 'high risk' group that could enrich the study population for intervention studies in pre-RA.

Progression of pre-rheumatoid arthritis to clinical disease of joints: Potential role of mesenchymal stem cells

Rheumatoid arthritis (RA) related autoimmunity is developed at mucosal sites due to the interplay between genetic risk factors and environmental triggers. The pre-RA phase that leads to anti-citrullinated protein antibodies, rheumatoid factor, and other autoantibodies spread in the systemic circulation may not affect articular tissue for years until a mysterious second hit triggers the localization of RA-related autoimmunity in joints. Several players in the joint microenvironment mediate the synovial innate and adaptive immunological processes, eventually leading to clinical synovitis. There still exists a gap in the early phase of RA pathogenesis, i.e., the progression of diseases from the systemic circulation to joints. The lack of better understanding of these events results in the inability to answer questions about why only after a certain point of time the disease appears in joints and why in some cases, it simply remains latent and doesn't affect joints at all. In the current review, we focused on the immunomodulatory and regenerative role of mesenchymal stem cells and associated exosomes in RA pathology. We also highlighted the age-related dysregulations in activities of mesenchymal stem cells and how that might trigger homing of systemic autoimmunity to joints.

A Practical Guide to 16S rRNA Microbiome Analysis in Musculoskeletal Disorders

Microbial taxonomic assignment based on 16S marker gene amplification requires multiple data transformations, often encompassing the use of a variety of computational platforms. Bioinformatics analysis may represent a bottleneck for researchers as many tools require programmatic access in order to implement the software. Here we describe a step-by-step approach for taxonomic assignment using QIIME2 and highlight the utility of graphical-based microbiome tools for further analysis and identification of biological relevant taxa with reference to an outcome of interest.

Relationship between gut microbiota and rheumatoid arthritis: A bibliometric analysis

Introduction

Rheumatoid arthritis (RA) is a multifactorial autoimmune disease. Recently, growing evidence demonstrates that gut microbiota (GM) plays an important role in RA. But so far, no bibliometric studies pertaining to GM in RA have ever been published. This study attempts to depict the knowledge framework in this field from a holistic and systematic perspective based on the bibliometric analysis.

Methods

Literature related to the involvement of GM in RA was searched and picked from the Web of Science Core Collection (WOSCC) database. The annual output, cooperation, hotspots, research status and development trend of this field were analyzed by bibliometric software (VOSviewer and Bibliometricx).

Results

255 original research articles and 204 reviews were included in the analysis. The articles in this field that can be retrieved in WOSCC were first published in 2004 and increased year by year since then. 2013 is a growth explosion point. China and the United States are the countries with the most contributions, and Harvard University is the affiliation with the most output. Frontiers in Immunology (total citations = 603) is the journal with the most publications and the fastest growth rate. eLife is the journal with the most citations (total citations = 1248). Scher, Jose U. and Taneja, Veena are the most productive and cited authors. The research in this field is mainly distributed in the evidence, mechanism and practical application of GM participating in RA through the analysis of keywords and documents. There is sufficient evidence to prove the close relationship between GM and RA, which lays the foundation for this field. This extended two colorful and tender branches of mechanism research and application exploration, which have made some achievements but still have broad exploration space. Recently, the keywords "metabolites", "metabolomics", "acid", "b cells", "balance", "treg cells", "probiotic supplementation" appeared most frequently, which tells us that research on the mechanism of GM participating in RA and exploration of its application are the hotspots in recent years.

Discussion

Taken together, these results provide a data-based and objective introduction to the GM participating in RA, giving readers a valuable reference to help guide future research.

Integrated Network Pharmacology and Experimental Validation Approach to Investigate the Mechanisms of Stigmasterol in the Treatment of Rheumatoid Arthritis

Background

Rheumatoid arthritis (RA) is a chronic inflammatory disease of the joints associated with systemic comorbidities. Sinomenium acutum is regarded as an effective traditional Chinese medicine (TCM) for the treatment of RA.

Materials and Methods

Based on network pharmacology and Gene Expression Omnibus (GEO) database, 33 RA-related differentially-expressed genes (DEGs) targeting active compounds of Sinomenium acutum were initially screened in our investigation.

Results

Gene Ontology (GO) and Kyoto encyclopaedia of genes and genome (KEGG) analyses found the important involvement of these DEGs in osteoclast differentiation, and finally 5 core DEGs, including NCF4, NFKB1, CYBA, IL-1β and NCF1 were determined through protein-protein interaction (PPI) network. We also identified the related active component of Sinomenium acutum include Stigmasterol. Finally, in order to experimentally verify these results, a rat model of collagen-induced arthritis (CIA) was established, and subsequently treated with Stigmasterol solution.

Conclusion

Similar to the healing effect of Indomethacin, Stigmasterol was observed to reduce the levels of inflammatory factors (IL-6 and IL-1β) and osteoclast differentiation-related factors (RANKL, ACP5 and Cathepsin K), which can also reduce the arthritis index score and alleviate the degree of pathological injury of rat ankle joints. The predictions and experimental data uncover the involvement of Stigmasterol, an active component of Sinomenium acutum, in regulation of osteoclast differentiation, exerting great medicinal potential in the treatment of RA.

Dysbiotic but nonpathogenic shift in the fecal mycobiota of patients with rheumatoid arthritis

Rheumatoid arthritis (RA) is closely associated with the oral and gut microbiomes. Fungal cell wall components initiate inflammatory arthritis in mouse models. However, little is known regarding the role of the fungal community in the pathogenesis of RA. To evaluate the association between RA and the gut microbiome, investigations of bacterial and fungal communities in patients with RA are necessary. Therefore, we investigated the compositions and associations of fecal bacterial and fungal communities in 30 healthy controls and 99 patients with RA. The relative abundances of Bifidobacterium and Blautia decreased, whereas the relative abundance of Streptococcus increased, in patients with RA. The relative abundance of Candida in the fecal fungal community was higher in patients with RA than in healthy controls, while the relative abundance of Aspergillus was higher in healthy controls than in patients with RA. Candida species-specific gene amplification showed that C. albicans was the most abundant species of Candida. Ordination analysis and random forest classification models supported the findings of structural changes in bacterial and fungal communities. Aspergillus was the core fecal fungal genus in healthy controls, although Saccharomyces spp. are typically predominant in Western cohorts. In addition, bacterial-fungal association analyses showed that the hub node had shifted from fungi to bacteria in patients with RA. The finding of fungal dysbiosis in patients with RA suggests that fungi play critical roles in the fecal microbial communities and pathogenesis of RA.

Preclinical Studies of Natural Products Targeting the Gut Microbiota: Beneficial Effects on Diabetes

Diabetes mellitus (DM) is a serious metabolic disease characterized by persistent hyperglycemia, with a continuously increasing morbidity and mortality. Although traditional treatments including insulin and oral hypoglycemic drugs maintain blood glucose levels within the normal range to a certain extent, there is an urgent need to develop new drugs that can effectively improve glucose metabolism and diabetes-related complications. Notably, accumulated evidence implicates that the gut microbiota is unbalanced in DM individuals and is involved in the physiological and pathological processes of this metabolic disease. In this review, we introduce the molecular mechanisms by which the gut microbiota contributes to the development of DM. Furthermore, we summarize the preclinical studies of bioactive natural products that exert antidiabetic effects by modulating the gut microbiota, aiming to expand the novel therapeutic strategies for DM prevention and management.

The Genetic, Environmental, and Immunopathological Complexity of Autoantibody-Negative Rheumatoid Arthritis

Differences in clinical presentation, response to treatment, and long-term outcomes between autoantibody-positive and -negative rheumatoid arthritis (RA) highlight the need for a better comprehension of the immunopathogenic events underlying the two disease subtypes. Whilst the drivers and perpetuators of autoimmunity in autoantibody-positive RA have started to be disclosed, autoantibody-negative RA remains puzzling, also due its wide phenotypic heterogeneity and its possible misdiagnosis. Genetic susceptibility appears to mostly rely on class I HLA genes and a number of yet unidentified non-HLA loci. On the background of such variable genetic predisposition, multiple exogeneous, endogenous, and stochastic factors, some of which are not shared with autoantibody-positive RA, contribute to the onset of the inflammatory cascade. In a proportion of the patients, the immunopathology of synovitis, at least in the initial stages, appears largely myeloid driven, with abundant production of proinflammatory cytokines and only minor involvement of cells of the adaptive immune system. Better understanding of the complexity of autoantibody-negative RA is still needed in order to open new avenues for targeted intervention and improve clinical outcomes.

Gut microbiome diversity and composition is associated with hypertension in women

OBJECTIVES

Animal studies support a role for the gut microbiota in hypertension development, but large human studies are lacking. Here, we investigated the relationship between hypertension prevalence and gut microbial composition in two cohorts.

METHODS

We included 871 unrelated TwinsUK women with faecal microbiome data (16s rRNA gene sequencing). Multivariable linear models adjusted for age, age2 and BMI as well as MiRKAT models, were used to estimate the association of hypertension with alpha- and beta-diversity metrics. To identify taxa associated with hypertension, a generalized additive model for location scale and shape was computed adjusting for covariates and multiple testing. Results were replicated in 448 women from PREDICT-1.

RESULTS

We found that measures of alpha diversity are significantly lower in hypertensive cases [Beta(95% confidence interval, 95% CI) = -0.05 (-0.095 to -0.004), P = 0.03] and a significant association between beta diversity and hypertension (FDR < 0.05). We identified and replicated two genera associated with hypertension. The genus, Ruminiclostridium 6 was less abundant in hypertension cases [meta-analysis (95% CI) = -0.31 (-0.5 to -0.13), P = 1 × 10-3]. The uncultured microbe Erysipelotrichacea-UCG003 was more abundant in hypertensive cases [meta-analysis (95% CI) = 0.46 (0.3-0.62), P = 1 × 10-4]. We genomically analysed the 16 s rRNA sequence and established a 100% identity match with the 16 s rRNA sequence of the genus Faecalibacillus. We functionally annotated Ruminiclostridium, identifying 83 metabolic pathways, including pathways previously linked to blood pressure regulation.

CONCLUSION

In this large human observation, we show that gut microbiome diversity and composition are associated with hypertension. Our results suggest that targeting the microbiome may be a novel means to prevent or treat hypertension.