Microbial and metabolic multi-omic correlations in systemic sclerosis patients

Exploring the role of gut microbiome in autoimmune diseases: A comprehensive review

As the industrialized society advances, there has been a gradual increase in the prevalence of autoimmune disorders. A probe into the fundamental causes has disclosed several factors in modern society that have an influence on the gut microbiome. These dramatic shifts in the gut microbiome are likely to be one of the reasons for the disarray in the immune system, and the relationship between the immune system and the gut microbiome emerging as a perennial hot topic of research. This review enumerates the findings from sequencing studies of gut microbiota on seven autoimmune diseases (ADs): Rheumatoid Arthritis (RA), Systemic Lupus Erythematosus (SLE), Ankylosing Spondylitis (AS), Systemic Sclerosis (SSc), Sjögren's Syndrome (SjS), Juvenile Idiopathic Arthritis (JIA), and Behçet's Disease (BD). It aims to identify commonalities in changes in the gut microbiome within the autoimmune disease cohort and characteristics specific to each disease. The dysregulation of the gut microbiome involves a disruption of the internal balance and the balance between the external environment and the host. This dysregulation impacts the host's immune system, potentially playing a role in the development of ADs. Damage to the gut epithelial barrier allows potential pathogens to translocate to the mucosal layer, contacting epithelial cells, disrupting tight junctions, and being recognized by antigen-presenting cells, which triggers an immune response. Primed T-cells assist B-cells in producing antibodies against pathogens; if antigen mimicry occurs, an immune response is generated in extraintestinal organs during immune cell circulation, clinically manifesting as ADs. However, current research is limited; advancements in sequencing technology, large-scale cohort studies, and fecal microbiota transplantation (FMT) research are expected to propel this field to new peaks.

Metabolomics in systemic sclerosis

Systemic sclerosis is a rare autoimmune condition leading to incurable complications. Therefore fast and precise diagnosis is crucial to prevent patient death and to maintain quality of life. Unfortunately, currently known biomarkers do not meet this need. To address this problem researchers use diverse approaches to elucidate the underlying aberrations. One of the methods applied is metabolomics. This modern technique enables a comprehensive assessment of multiple compound concentrations simultaneously. As it has been gaining popularity, we found it necessary to summarize metabolomic studies presented so far in a narrative review. We found 11 appropriate articles. All of the researchers found significant differences between patients and control groups, whereas the reported findings were highly inconsistent. Additionally, we have found the investigated groups in most studies were scarcely described, and the inclusion/exclusion approach was diverse. Therefore, further study with meticulous patient assessment is necessary.

The Potential Role of Butyrate in the Pathogenesis and Treatment of Autoimmune Rheumatic Diseases

The gut microbiota is a complex ecosystem of microorganisms residing in the human gastrointestinal tract, playing a crucial role in various biological processes and overall health maintenance. Dysbiosis, an imbalance in the composition and function of the gut microbiota, is linked to systemic autoimmune diseases (SAD). Short-chain fatty acids (SCFAs), especially butyrate, produced by the gut microbiota through the fermentation of dietary fibers, play a significant role in immunomodulation and maintaining intestinal homeostasis. Butyrate is essential for colonocyte energy, anti-inflammatory responses, and maintaining intestinal barrier integrity. Studies show reduced butyrate-producing bacteria in SAD patients, suggesting that increasing butyrate levels could have therapeutic benefits. Butyrate's anti-inflammatory effects and its potential therapeutic role have been studied in rheumatoid arthritis, Sjogren's syndrome, systemic lupus erythematosus, systemic sclerosis, and Behçet's disease. Despite promising in vitro and animal model results, human studies are limited, and the optimal strategies for modulating dysbiosis in SADs remain elusive. This review explores the current evidence on the immunoregulatory role of butyrate and its potential therapeutic effects in SAD.

Comprehensive analysis of the oral microbiota and metabolome change in patients of burning mouth syndrome with psychiatric symptoms

Background

Burning mouth syndrome (BMS) is a chronic idiopathic facial pain with intraoral burning or dysesthesia. BMS patients regularly suffer from anxiety/depression, and the association of psychiatric symptoms with BMS has received considerable attention in recent years. The aims of this study were to investigate the potential interplay between psychiatric symptoms and BMS.

Methods

Using 16S rRNA sequencing and liquid chromatography-mass spectrometry (LC/MS) to evaluate the oral microbiota and saliva metabolism of 40 BMS patients [including 29 BMS patients with depression or anxiety symptoms (DBMS)] and 40 age matched healthy control (HC).

Results

The oral microbiota composition in BMS exhibited no significant differences from HC, although DBMS manifested decreased α-diversity relative to HC. Noteworthy was the discernible elevation in the abundance of proinflammatory microorganisms within the oral microbiome of individuals with DBMS. Parallel findings in LC/MS analyses revealed discernible disparities in metabolites between DBMS and HC groups. Principal differential metabolites were notably enriched in amino acid metabolism and lipid metabolism, exhibiting associations with infectious and immunological diseases. Furthermore, the integrated analysis underscores a definitive association between the oral microbiome and metabolism in DBMS.

Conclusions

This study suggests possible future modalities for better understanding the pathogenesis and personalized treatment plans of BMS.

Managing gastrointestinal manifestations in systemic sclerosis, a mechanistic approach

INTRODUCTION

Systemic sclerosis (SSc) is a connective tissue disease with heterogeneous presentation. Gastrointestinal (GI) complications of SSc are characterized by esophageal reflux, abnormal motility, and microbiome dysbiosis, which impact patient quality of life and mortality. Preventative therapeutics are lacking, with management primarily aimed at symptomatic control.

AREAS COVERED

A broad literature review was conducted through electronic databases and references from key articles. We summarize the physiology of gastric acid production and GI motility to provide context for existing therapies, detail the current understanding of SSc-GI disease, and review GI medications studied in SSc. Finally, we explore new therapeutic options. We propose a management strategy that integrates data on drug efficacy with knowledge of disease pathophysiology, aiming to optimize future therapeutic targets.

EXPERT OPINION

SSc-GI complications remain a challenge for patients, clinicians, and investigators alike. Management presently focuses on treating symptoms and minimizing mucosal damage. Little evidence exists to suggest immunosuppressive therapy halts progression of GI involvement or reverses damage, leaving many unanswered questions about the optimal clinical approach. Further research focused on identifying patients at risk for GI progression, and the underlying mechanism(s) that drive disease will provide opportunities to prevent long-term damage, and significantly improve patient quality of life.

The differential crosstalk of the skin-gut microbiome axis as a new emerging actor in systemic sclerosis

OBJECTIVES

We characterized the microbiota in SSc, focusing on the skin-oral-gut axis and the serum and faecal free fatty acid (FFA) profile.

METHODS

Twenty-five SSc patients with ACA or anti-Scl70 autoantibodies were enrolled. The microbiota of faecal, saliva and superficial epidermal samples was assessed through next-generation sequencing analysis. GC-MS was used to quantify faecal and serum FFAs. Gastrointestinal symptoms were investigated with the University of California Los Angeles Scleroderma Clinical Trial Consortium Gastrointestinal Tract Instrument (UCLA GIT-2.0) questionnaire.

RESULTS

The ACA+ and anti-Scl70+ groups displayed different cutaneous and faecal microbiota profiles. The classes of cutaneous Sphingobacteriia and Alphaproteobacteria, the faecal phylum Lentisphaerae, the levels of the classes Lentisphaeria and Opitutae, and the genus NA-Acidaminococcaceae were significantly higher in faecal samples from the ACA+ patients than in samples from the anti-Scl70+ patients. The cutaneous Sphingobacteria and the faecal Lentisphaerae were significantly correlated (rho = 0.42; P = 0.03). A significant increase in faecal propionic acid was observed in ACA+ patients. Moreover, all levels of faecal medium-chain FFAs and hexanoic acids were significantly higher in the ACA+ group than in the anti-Scl70+ group (P < 0.05 and P < 0.001, respectively). In the ACA+ group, the analysis of the serum FFA levels showed an increasing trend in valeric acid.

CONCLUSION

Different microbiota signatures and FFA profiles were found for the two groups of patients. Despite being in different body districts, the cutaneous Sphingobacteria and faecal Lentisphaerae appear interdependent.

Dysbiosis of lower respiratory tract microbiome are associated with proinflammatory states in non-small cell lung cancer patients

BACKGROUND

The lung has a sophisticated microbiome, and respiratory illnesses are greatly influenced by the lung microbiota. Despite the fact that numerous studies have shown that lung cancer patients have a dysbiosis as compared to healthy people, more research is needed to explore the association between the microbiota dysbiosis and immune profile within the tumor microenvironment (TME).

METHODS

In this study, we performed metagenomic sequencing of tumor and normal tissues from 61 non-small cell lung cancer (NSCLC) patients and six patients with other lung diseases. In order to characterize the impact of the microbes in TME, the cytokine concentrations of 24 lung tumor and normal tissues were detected using a multiple cytokine panel.

RESULTS

Our results showed that tumors had lower microbiota diversity than the paired normal tissues, and the microbiota of NSCLC was enriched in Proteobacteria, Firmicutes, and Actinobacteria. In addition, proinflammatory cytokines such as IL-8, MIF, TNF- α, and so on, were significantly upregulated in tumor tissues.

CONCLUSION

We discovered a subset of bacteria linked to host inflammatory signaling pathways and, more precisely, to particular immune cells. We determined that lower airway microbiome dysbiosis may be linked to the disruption of the equilibrium of the immune system causing lung inflammation. The spread of lung cancer may be linked to specific bacteria.

Treatable Traits in Systemic Sclerosis

Systemic sclerosis (SSc) is a chronic systemic disease within the spectrum of connective tissue diseases, specifically characterized by vascular abnormalities and inflammatory and fibrotic involvement of the skin and internal organs resulting in high morbidity and mortality. The clinical phenotype of SSc is heterogeneous, and serum autoantibodies together with the extent of skin involvement have a predictive value in the risk stratification. Current recommendations include an organ-based management according to the predominant involvement with only limited individual factors included in the treatment algorithm. Similar to what has been proposed for other chronic diseases, we hypothesize that a "treatable trait" approach based on relevant phenotypes and endotypes could address the unmet needs in SSc stratification and treatment to maximize the outcomes. We provide herein a comprehensive review and a critical discussion of the literature regarding potential treatable traits in SSc, focusing on established and candidate biomarkers, with the purpose of setting the bases for a precision medicine-based approach. The discussion, structured based on the organ involvement, allows to conjugate the pathogenetic mechanisms of tissue injury with the proposed predictors, particularly autoantibodies and other serum biomarkers. Ultimately, we are convinced that precision medicine is the ideal guide to manage a complex condition such as SSc for which available treatments are largely unsatisfactory.

Metabolic fingerprinting of systemic sclerosis: a systematic review

Introduction: Systemic sclerosis (SSc) is a chronic autoimmune disease, marked by an unpredictable course, high morbidity, and increased mortality risk that occurs especially in the diffuse and rapidly progressive forms of the disease, characterized by fibrosis of the skin and internal organs and endothelial dysfunction. Recent studies suggest that the identification of altered metabolic pathways may play a key role in understanding the pathophysiology of the disease. Therefore, metabolomics might be pivotal in a better understanding of these pathogenic mechanisms. Methods: Through a systematic review of the literature following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Guidelines (PRISMA), searches were done in the PubMed, EMBASE, Web of Science, and Scopus databases from 2000 to September 2022. Three researchers independently reviewed the literature and extracted the data based on predefined inclusion and exclusion criteria. Results: Of the screened studies, 26 fulfilled the inclusion criteria. A total of 151 metabolites were differentially distributed between SSc patients and healthy controls (HC). The main deregulated metabolites were those derived from amino acids, specifically homocysteine (Hcy), proline, alpha-N-phenylacetyl-L-glutamine, glutamine, asymmetric dimethylarginine (ADMA), citrulline and ornithine, kynurenine (Kyn), and tryptophan (Trp), as well as acylcarnitines associated with long-chain fatty acids and tricarboxylic acids such as citrate and succinate. Additionally, differences in metabolic profiling between SSc subtypes were identified. The diffuse cutaneous systemic sclerosis (dcSSc) subtype showed upregulated amino acid-related pathways involved in fibrosis, endothelial dysfunction, and gut dysbiosis. Lastly, potential biomarkers were evaluated for the diagnosis of SSc, the identification of the dcSSc subtype, pulmonary arterial hypertension, and interstitial lung disease. These potential biomarkers are within amino acids, nucleotides, carboxylic acids, and carbohydrate metabolism. Discussion: The altered metabolite mechanisms identified in this study mostly point to perturbations in amino acid-related pathways, fatty acid beta-oxidation, and in the tricarboxylic acid cycle, possibly associated with inflammation, vascular damage, fibrosis, and gut dysbiosis. Further studies in targeted metabolomics are required to evaluate potential biomarkers for diagnosis, prognosis, and treatment response.

Desulfovibrio in the Gut: The Enemy within?

Desulfovibrio (DSV) are sulfate-reducing bacteria (SRB) that are ubiquitously present in the environment and as resident commensal bacteria within the human gastrointestinal tract. Though they are minor residents of the healthy gut, DSV are opportunistic pathobionts that may overgrow in the setting of various intestinal and extra-intestinal diseases. An increasing number of studies have demonstrated a positive correlation between DSV overgrowth (bloom) and various human diseases. While the relationship between DSV bloom and disease pathology has not been clearly established, mounting evidence suggests a causal role for these bacteria in disease development. As DSV are the most predominant genera of SRB in the gut, this review summarizes current knowledge regarding the relationship between DSV and a variety of diseases. In this study, we also discuss the mechanisms by which these bacteria may contribute to disease pathology.

Gut microbiota combined with fecal metabolomics reveals the effects of FuFang Runzaoling on the microbial and metabolic profiles in NOD mouse model of Sjögren's syndrome

OBJECTIVE

Sjögren's syndrome (SS) is an inflammatory autoimmune disease characterized by high levels of chronic lymphocyte infiltration. Differences and dysfunction in the gut microbiota and metabolites may be closely related to the pathogenesis of SS. The purpose of this study was to reveal the relationship between the gut microbiota and metabolome in NOD mice as a model of SS and the role of FuFang Runzaoling (FRZ), which is a clinically effective in treating SS.

METHODS

NOD mice were gavaged with FRZ for 10 weeks. The ingested volume of drinking water, submandibular gland index, pathologic changes of the submandibular glands, and serum cytokines interleukin (IL)-6, IL-10, IL-17 A, and tumor necrosis factor-alpha (TNF-α) were determined. The roles of FRZ on gut microbiota and fecal metabolites were explored by 16 S rRNA gene sequencing and liquid chromatography-mass spectrometry (LC-MC), respectively. The correlation between them was determined by Pearson correlation analysis.

RESULTS

Compared with the model group, the drinking water volume of NOD mice treated with FRZ increased and the submandibular gland index decreased. FRZ effectively ameliorated lymphocyte infiltration in the small submandibular glands in mice. Serum levels of IL-6, TNF-α, and IL-17 A decreased, and IL-10 increased. The Firmicutes/Bacteroidetes ratio in the FRZ treatment group was higher. FRZ significantly downregulated the relative abundance of the family Bacteroidaceae and genus Bacteroides, and significantly upregulated the relative abundance of genus Lachnospiraceae_UCG-001. Orthogonal projections to latent structures discriminant analysis (OPLS-DA) revealed the significant change in fecal metabolites after FRZ treatment. Based on criteria of OPLS-DA variable influence on projection > 1, P < 0.05, and fragmentation score > 50, a total of 109 metabolites in the FRZ-H group were differentially regulated (47 downregulated and 62 upregulated) compared to their expressions in the model group. Kyoto Encyclopedia of Genes and Genomes pathway analysis revealed enriched metabolic of sphingolipid metabolism, retrograde endocannabinoid signaling, GABAergic synapse, necroptosis, arginine biosynthesis, and metabolism of histidine, alanine, aspartate, and glutamate. Correlation analysis between gut microbiota and fecal metabolites suggested that the enriched bacteria were related to many key metabolites.

CONCLUSIONS

Taken together, we found FRZ could reduce the inflammatory responses in NOD mice by regulating the gut microbiota, fecal metabolites, and their correlation to emerge a therapeutic effect on mice with SS. This will lay the foundation for the further studies and applications of FRZ, and the use of gut microbiotas as drug targets to treat SS.

Serum metabolite differences detected by HILIC UHPLC-Q-TOF MS in systemic sclerosis

BACKGROUND

Systemic sclerosis (SSc) is a chronic autoimmune disease characterized by extensive fibrosis and vascular damage. Vasculopathy, activation of the immune system, and diffuse fibrosis are all involved in the fatal pathogenesis of SSc. However, little metabolomic research has been conducted in SSc.

METHODS

This study included 30 SSc patients and 30 healthy individuals. The metabolite differences in serum samples were analyzed using ultra-high-pressure liquid chromatography and quadrupole-time-of-flight mass spectrometry. Meanwhile, serum metabolites were analyzed in patients with systemic involvement (lung or skin fibrosis).

RESULTS

A total of 2360 ion peaks were detected, all of which were attributable to 38 metabolites. These metabolites primarily consisted of fatty acids, amino acids, and glycerophospholipids, which were the major metabolic pathways altered in SSc patients. Glutamine metabolism was the main pathway altered in SSc patients with lung involvement, whereas amino acid metabolism and steroid hormone biosynthesis were the main pathways altered in SSc patients with skin involvement.

CONCLUSION

These findings suggested that metabolic profiles and pathways differed between SSc patients and healthy people, potentially providing new targets for SSc-directed therapeutics and diagnostics. Key Points • Metabolic profiles and pathways differed between SSc patients and healthy people. • The levels of trans-dehydroandrosterone are substantially lower in lcSSc than in dcSSc, potentially providing new targets for SSc patients with skin involvement. • L-glutamine could be used as a serum metabolic marker and a therapeutic target for SSc patients with lung involvement.

The Microbiome in Systemic Sclerosis: Pathophysiology and Therapeutic Potential

Systemic sclerosis (SSc), also known as scleroderma, is an autoimmune disease with unknown etiology characterized by multi-organ fibrosis. Despite substantial investigation on SSc-related cellular and molecular mechanisms, effective therapies are still lacking. The skin, lungs, and gut are the most affected organs in SSc, which act as physical barriers and constantly communicate with colonized microbiota. Recent reports have documented a unique microbiome signature, which may be the pathogenic trigger or driver of SSc. Since gut microbiota influences the efficacy and toxicity of oral drugs, evaluating drug-microbiota interactions has become an area of interest in disease treatment. The existing evidence highlights the potential of the microbial challenge as a novel therapeutic option in SSc. In this review, we have summarized the current knowledge about molecular mechanisms of SSc and highlighted the underlying role of the microbiome in SSc pathogenesis. We have also discussed the latest therapeutic interventions using microbiomes in SSc, including drug-microbiota interactions and animal disease models. This review aims to elucidate the pathophysiological connection and therapeutic potential of the microbiome in SSc. Insights into the microbiome will significantly improve our understanding of etiopathogenesis and developing therapeutics for SSc.

The Role of the Microbiome in Connective-Tissue-Associated Interstitial Lung Disease and Pulmonary Vasculitis

The microbiome can trigger and maintain immune-mediated diseases and is associated with the severity and prognosis of idiopathic pulmonary fibrosis, which is the prototype of interstitial lung diseases (ILDs). The latter can be a major cause of morbidity and mortality in patients with connective-tissue diseases (CTD). In the present review, we discuss the current evidence regarding microbiome in CTD-ILD and pulmonary vasculitis. In patients with rheumatoid arthritis (RA) the BAL microbiota is significantly less diverse and abundant, compared to healthy controls. These changes are associated with disease severity. In systemic sclerosis (SSc), gastrointestinal (GI)-dysbiosis is associated with ILD. Butyrate acid administration as a means of restoration of GI-microbiota has reduced the degree of lung fibrosis in animal models. Although related studies are scarce for SLE and Sjögren's syndrome, studies of the gut, oral and ocular microbiome provide insights into the pathogenesis of these diseases. In ANCA-associated vasculitis, disease severity and relapses have been associated with disturbed nasal mucosa microbiota, with immunosuppressive treatment restoring the microbiome changes. The results of these studies suggest however no causal relation. More studies of the lung microbiome in CTD-ILDs are urgently needed, to provide a better understanding of the pathogenesis of these diseases.

Predicting the Progression of Very Early Systemic Sclerosis: Current Insights

Systemic sclerosis (SSc) is a complex autoimmune connective tissue disease with distinct pathological hallmarks (ie, inflammation, vasculopathy, fibrosis) that may predominate at different stages in the disease course with varying severity. Initial efforts to classify patients with SSc identified a subset of patients with very early SSc. These patients possessed signs of SSc (eg, Raynaud phenomenon, SSc specific autoantibodies and/or nailfold capillary abnormalities) without fulfilling complete SSc classification criteria. Recognizing the inherent value in early diagnosis and intervention in SSc, researchers have endeavored to identify risk factors for progression from very early SSc to definite SSc. The present review summarizes the clinical phenotype of patients with very early and early SSc. Through a scoping review of recent literature, this review also describes risk factors for progression to definite SSc with a focus on the specific clinical features that arise early in the SSc disease course (eg, diffuse cutaneous sclerosis, interstitial lung disease, esophageal dysfunction, renal crisis, cardiac involvement). In addition to clinical risk factors, this review provides evidence for how biological data (ie, serological, genomic, proteomic profiles, skin bioengineering methods) can be integrated into risk assessment models in the future. Furthering our understanding of biological features of very early SSc will undoubtedly provide novel insights into SSc pathogenesis and may illuminate new therapeutic targets to prevent progression of SSc.

Gut microbiota in systemic lupus erythematosus patients and lupus mouse model: a cross species comparative analysis for biomarker discovery

An increasing number of studies have provided strong evidence that gut microbiota interact with the immune system and stimulate various mechanisms involved in the pathogenesis of auto-immune diseases such as Systemic Lupus Erythematosus (SLE). Indeed, gut microbiota could be a source of diagnostic and prognostic biomarkers but also hold the promise to discover novel therapeutic strategies. Thus far, specific SLE microbial signatures have not yet been clearly identified with alteration patterns that may vary between human and animal studies. In this study, a comparative analysis of a clinically well-characterized cohort of adult patients with SLE showed reduced biodiversity, a lower Firmicutes/Bacteroidetes (F/B) ratio, and six differentially abundant taxa compared with healthy controls. An unsupervised clustering of patients with SLE patients identified a subgroup of patients with a stronger alteration of their gut microbiota. Interestingly, this clustering was strongly correlated with the disease activity assessed with the Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) score (p = 0.03, odd ratio = 15) and the identification of specific alterations involving the F/B ratio and some different taxa. Then, the gut microbiota of pristane-induced lupus and control mice were analyzed for comparison with our human data. Among the six differentially abundant taxa of the human disease signature, five were common with our murine model. Finally, an exhaustive cross-species comparison between our data and previous human and murine SLE studies revealed a core-set of gut microbiome species that might constitute biomarker panels relevant for future validation studies.

Toward Molecular Stratification and Precision Medicine in Systemic Sclerosis

Systemic sclerosis (SSc), a complex multi-systemic disease characterized by immune dysregulation, vasculopathy and fibrosis, is associated with high mortality. Its pathogenesis is only partially understood. The heterogenous pathological processes that define SSc and its stages present a challenge to targeting appropriate treatment, with differing treatment outcomes of SSc patients despite similar initial clinical presentations. Timing of the appropriate treatments targeted at the underlying disease process is critical. For example, immunomodulatory treatments may be used for patients in a predominantly inflammatory phase, anti-fibrotic treatments for those in the fibrotic phase, or combination therapies for those in the fibro-inflammatory phase. In advancing personalized care through precision medicine, groups of patients with similar disease characteristics and shared pathological processes may be identified through molecular stratification. This would improve current clinical sub-setting systems and guide personalization of therapies. In this review, we will provide updates in SSc clinical and molecular stratification in relation to patient outcomes and treatment responses. Promises of molecular stratification through advances in high-dimensional tools, including omic-based stratification (transcriptomics, genomics, epigenomics, proteomics, cytomics, microbiomics) and machine learning will be discussed. Innovative and more granular stratification systems that integrate molecular characteristics to clinical phenotypes would potentially improve therapeutic approaches through personalized medicine and lead to better patient outcomes.

Microbiome Changes in Connective Tissue Diseases and Vasculitis: Focus on Metabolism and Inflammation

The microbial community acts as an active player in maintaining homeostasis and immune functions through a continuous and changeable cross-talk with the host immune system. Emerging evidence suggests that altered microbial composition, known as dysbiosis, might perturb the delicate balance between the microbiota and the immune system, triggering inflammation and potentially contributing to the pathogenesis and development of chronic inflammatory diseases. This review will summarize the current evidence about the microbiome-immunity cross-talk, especially focusing on the microbiota alterations described in patients with rheumatic diseases and on the recent findings concerning the interaction between microbiota, metabolic function, and the immune system.

Comprehensive Analysis of the Relationships Between the Gut Microbiota and Fecal Metabolome in Individuals With Primary Sjogren's Syndrome by 16S rRNA Sequencing and LC-MS-Based Metabolomics

The gut microbiota has been associated with primary Sjogren’s syndrome (pSS), yet the biological implications of these associations are often elusive. We analyzed the fecal microbiota through 16S rRNA gene amplification and sequencing in 30 patients with pSS and 20 healthy controls (HCs); At the same time, the fecal metabolome was characterized by ultrahigh-performance liquid chromatography–mass spectrometry. In addition, correlation analyses of microbiota and metabolome data were performed to identify meaningful associations. We found that the microbiota composition of pSS patients was significantly different from that of HCs. The pSS gut microbiota is characterized by increased abundances of proinflammatory microbes, especially Escherichia-Shigella, and decreased abundances of anti-inflammatory microbes. Concerning the metabolome, a multivariate model with 33 metabolites efficiently distinguished cases from controls. Through KEGG enrichment analysis, we found that these metabolites were mainly involved in amino acid metabolism and lipid metabolism. The correlation analysis indicated that there were certain correlations between the microbiota and metabolism in pSS patients. In addition, an abundance of Escherichia-Shigella was found to be correlated with high levels of four metabolites (aflatoxin M1, glycocholic acid, L-histidine and phenylglyoxylic acid). Our research suggests that in pSS patients, the gut microbiota is characterized by a specific combination of proinflammatory changes and metabolic states. Escherichia-Shigella is a factor related to gut dysbiosis, which may promote intestinal damage and affect amino acid metabolism.

Disease Features and Gastrointestinal Microbial Composition in Patients with Systemic Sclerosis from Two Independent Cohorts

OBJECTIVE

The study objective was to examine alterations in gastrointestinal (GI) microbial composition in patients with systemic sclerosis (SSc) and to investigate the relationship between SSc features and GI microbiota using two independent, international cohorts.

METHODS

Prospective patients with SSc from Lund University (LU), Sweden, from the University of California, Los Angeles (UCLA), United States, and control subjects provided stool specimens for 16S ribosomal RNA sequencing. Alpha and beta diversity analyses were performed. Multivariate negative binomial models identified differentially abundant genera between groups.

RESULTS

Patients from LU with SSc (n = 106) with recent SSc diagnosis (median disease duration 2.0 years) had lower abundance of commensal genera (eg, Faecalibacterium) and higher abundance of pathobiont genera (eg, Desulfovibrio) than LU-controls (n = 85). Patients from UCLA with SSc (n = 71) had a similar prevalence of females, a similar body mass index, and similar age but an increased disease duration (median 7.1 years) compared with patients from LU with SSc. Factors associated with beta diversity in patients with SSc from both LU and UCLA included disease duration (P = 0.0016), interstitial lung disease (P = 0.003), small intestinal bacterial overgrowth (P = 0.002), and immunosuppression use (P = 0.014). In multivariable analysis, the UCLA-SSc cohort had higher abundance of specific pathobiont genera (eg, Streptococcus) compared with the LU-SSc cohort.

CONCLUSION

Enrichments and depletions in certain microbial genera were observed in patients recently diagnosed with SSc, suggesting that dysbiosis is present in early SSc. Specific disease features were independently associated with fecal microbial composition in both cohorts. After controlling for these factors, the abundance of several pathobiont bacteria differed between the cohorts, suggesting that environmental factors, along with disease manifestations, should be considered in future SSc studies.

Plasma Metabolomic Profiling Reveals Four Possibly Disrupted Mechanisms in Systemic Sclerosis

Systemic sclerosis (SSc) is a rare systemic autoimmune disorder marked by high morbidity and increased risk of mortality. Our study aimed to analyze metabolomic profiles of plasma from SSc patients by using targeted and untargeted metabolomics approaches. Furthermore, we aimed to detect biochemical mechanisms relevant to the pathophysiology of SSc. Experiments were performed using high-performance liquid chromatography coupled to mass spectrometry technology. The investigation of plasma samples from SSc patients (n = 52) compared to a control group (n = 48) allowed us to identify four different dysfunctional metabolic mechanisms, which can be assigned to the kynurenine pathway, the urea cycle, lipid metabolism, and the gut microbiome. These significantly altered metabolic pathways are associated with inflammation, vascular damage, fibrosis, and gut dysbiosis and might be relevant for the pathophysiology of SSc. Further studies are needed to explore the role of these metabolomic networks as possible therapeutic targets of SSc.

Dysbiosis and Gut Microbiota Modulation in Systemic Sclerosis

ABSTRACT

Gastrointestinal (GI) involvement is an early manifestation in systemic sclerosis (SSc), affecting more than 90% of patients, and severe GI disease is a marker of poor prognosis and mortality. Recent studies have hypothesized that alterations of the intestinal microbiota, known as dysbiosis, may represent 1 of the possible environmental factors influencing SSc disease status. In addition, specific microorganisms may be associated with SSc pathogenesis, progression, and GI manifestations. Therapeutic approaches aiming to modulate the intestinal microbiota have emerged, as alternatives to treat GI symptoms, and dietary interventions, probiotic administration, and fecal microbiota transplantation are potential therapies for SSc patients. However, given the complexity and variability of pathogenesis and clinical manifestations in SSc, these therapies need to be combined with additional interventions that target other disease components. Here, we summarize studies addressing intestinal dysbiosis in SSc and discuss the potential of microbiota modulators to treat SSc-related GI disorders.

The Interplay between Autonomic Nervous System and Inflammation across Systemic Autoimmune Diseases

The autonomic nervous system (ANS) and the immune system are deeply interrelated. The ANS regulates both innate and adaptive immunity through the sympathetic and parasympathetic branches, and an imbalance in this system can determine an altered inflammatory response as typically observed in chronic conditions such as systemic autoimmune diseases. Rheumatoid arthritis, systemic lupus erythematosus, and systemic sclerosis all show a dysfunction of the ANS that is mutually related to the increase in inflammation and cardiovascular risk. Moreover, an interaction between ANS and the gut microbiota has direct effects on inflammation homeostasis. Recently vagal stimulation techniques have emerged as an unprecedented possibility to reduce ANS dysfunction, especially in chronic diseases characterized by pain and a decreased quality of life as well as in chronic inflammation.

A review and roadmap of the skin, lung and gut microbiota in systemic sclerosis

As our understanding of the genetic underpinnings of SSc increases, questions regarding the environmental trigger(s) that induce and propagate SSc in the genetically predisposed individual emerge. The interplay between the environment, the immune system, and the microbial species that inhabit the patient's skin and gastrointestinal tract is a pathobiological frontier that is largely unexplored in SSc. The purpose of this review is to provide an overview of the methodologies, experimental study results and future roadmap for elucidating the relationship between the SSc host and his/her microbiome.

Intestinal Microbiome in Hematopoietic Stem Cell Transplantation For Autoimmune Diseases: Considerations and Perspectives on Behalf of Autoimmune Diseases Working Party (ADWP) of the EBMT

Over the past decades, hematopoietic stem cell transplantation (HSCT) has been evolving as specific treatment for patients with severe and refractory autoimmune diseases (ADs), where mechanistic studies have provided evidence for a profound immune renewal facilitating the observed beneficial responses. The intestinal microbiome plays an important role in host physiology including shaping the immune repertoire. The relationships between intestinal microbiota composition and outcomes after HSCT for hematologic diseases have been identified, particularly for predicting the mortality from infectious and non-infectious causes. Furthermore, therapeutic manipulations of the gut microbiota, such as fecal microbiota transplant (FMT), have emerged as promising therapeutic approaches for restoring the functional and anatomical integrity of the intestinal microbiota post-transplantation. Although changes in the intestinal microbiome have been linked to various ADs, studies investigating the effect of intestinal dysbiosis on HSCT outcomes for ADs are scarce and require further attention. Herein, we describe some of the landmark microbiome studies in HSCT recipients and patients with chronic ADs, and discuss the challenges and opportunities of microbiome research for diagnostic and therapeutic purposes in the context of HSCT for ADs.

Current Concepts on the Pathogenesis of Systemic Sclerosis

From the clinical standpoint, systemic sclerosis (SSc) is characterized by skin and internal organ fibrosis, diffuse fibroproliferative vascular modifications, and autoimmunity. Clinical presentation and course are highly heterogenous and life expectancy variably affected mostly dependent on lung and heart involvement. SSc touches more women than men with differences in disease severity and environmental exposure. Pathogenetic events originate from altered homeostasis favored by genetic predisposition, environmental cues and a variety of endogenous and exogenous triggers. Epigenetic modifications modulate SSc pathogenesis which strikingly associate profound immune-inflammatory dysregulation, abnormal endothelial cell behavior, and cell trans-differentiation into myofibroblasts. SSc myofibroblasts show enhanced survival and enhanced extracellular matrix deposition presenting altered structure and altered physicochemical properties. Additional cell types of likely pathogenic importance are pericytes, platelets, and keratinocytes in conjunction with their relationship with vessel wall cells and fibroblasts. In SSc, the profibrotic milieu is favored by cell signaling initiated in the one hand by transforming growth factor-beta and related cytokines and in the other hand by innate and adaptive type 2 immune responses. Radical oxygen species and invariant receptors sensing danger participate to altered cell behavior. Conventional and SSc-specific T cell subsets modulate both fibroblasts as well as endothelial cell dysfunction. Beside autoantibodies directed against ubiquitous antigens important for enhanced clinical classification, antigen-specific agonistic autoantibodies may have a pathogenic role. Recent studies based on single-cell RNAseq and multi-omics approaches are revealing unforeseen heterogeneity in SSc cell differentiation and functional states. Advances in system biology applied to the wealth of data generated by unbiased screening are allowing to subgroup patients based on distinct pathogenic mechanisms. Deciphering heterogeneity in pathogenic mechanisms will pave the way to highly needed personalized therapeutic approaches.

Desulfovibrio is not always associated with adverse health effects in the Guangdong Gut Microbiome Project

Desulfovibrio (DSV) is frequently found in the human intestine but limited knowledge is available regarding the relationship between DSV and host health. In this study, we analyzed large-scale cohort data from the Guangdong Gut Microbiome Project to study the ecology of DSV and the associations of DSV and host health parameters. Phylogenetic analysis showed that Desulfovibrio piger might be the most common and abundant DSV species in the GGMP. Predominant sub-OTUs of DSV were positively associated with bacterial community diversity. The relative abundance of DSV was positively correlated with beneficial genera, including Oscillospira, Coprococcus,Ruminococcus,Akkermansia, Roseburia,Faecalibacterium, andBacteroides, and was negatively associated with harmful genera, such as Clostridium,Escherichia,Klebsiella, and Ralstonia. Moreover, the relative abundance of DSV was negatively correlated with body mass index, waist size, triglyceride levels, and uric acid levels. This suggests that DSV is associated with healthy hosts in some human populations.

Fecal microbiome differs between patients with systemic sclerosis with and without small intestinal bacterial overgrowth

Introduction:

Gastrointestinal manifestations of systemic sclerosis affect up to 90% of patients, with symptoms including diarrhea and constipation. Small intestinal bacterial overgrowth is a condition associated with increased numbers of pathogenic bacteria in the small bowel. While currently unknown, it has been suggested that dysregulation of the fecal microbiota may play a role in the development of systemic sclerosis and small intestinal bacterial overgrowth.

Objectives:

Our study aimed to describe the fecal microbiota of patients with systemic sclerosis and compare it between those with and without a diagnosis of small intestinal bacterial overgrowth. We also compared the fecal microbiota of systemic sclerosis patients with that of healthy controls to understand the association between particular bacterial taxa and clinical gastrointestinal manifestations of systemic sclerosis.

Methods:

A total of 29 patients with systemic sclerosis underwent breath testing to assess for small intestinal bacterial overgrowth, provided stool samples to determine taxonomic assignments, and completed the University of California Los Angeles Scleroderma Clinical Trial Consortium Gastrointestinal Tract 2.0, which details symptoms and quality-of-life factors. Stool samples were compared between systemic sclerosis patients with and without small intestinal bacterial overgrowth, and between patients with systemic sclerosis and a healthy control cohort (n = 20), aged 18–80 years.

Results:

Fecal microbiome analyses demonstrated differences between systemic sclerosis patients with and without small intestinal bacterial overgrowth and differences in the diversity of species between healthy controls and patients with systemic sclerosis. Trends were also observed in anticentromere antibody systemic sclerosis patients, including higher Alistipies indistincus spp. levels associated with increased methane levels of breath gas testing and higher Slakia spp. levels associated with increased rates of fecal soiling.

Conclusions:

Our results suggest that changes to the fecal microbiome occur in patients with small intestinal bacterial overgrowth and systemic sclerosis when compared to healthy controls. As a cross-sectional study, the potential pathophysiologic role of an altered microbiome in the development of systemic sclerosis was not considered and hence needs to be further investigated.

Digestive Dysbiosis in Systemic Scleroderma: a Review

Systemic sclerosis (SSc) is a rare autoimmune disease characterized by widespread microvasculopathy, inflammation, and fibrosis of the skin and internal organs. The involvement of the gastrointestinal tract is associated with a wide variety of symptoms and affects circa 90% of patients during the course of the disease. The gastrointestinal microbiota contains trillions of microbial cells and has been found to contribute to both local and systemic homeostasis. In both health and disease, a dynamic interrelationship between gut microbiome activity and the host immune system has been identified. Gastrointestinal dysbiosis has been described as having an important role in obesity, diabetes mellitus, liver disease, cardiovascular and neuropsychiatric disorders, neoplasia, as well as autoimmunity. Recent scientific data indicates a notable role of dysbiosis in the pathogenesis of SSc-related digestive involvement together with various other clinical manifestations. The present review aims to summarize the recent findings regarding digestive dysbiosis as well as the relationship between gastrointestinal microbiota and certain features of SSc.

Gut Microbiota Aberration in Patients of Systemic Sclerosis and Bleomycin-Induced Mice Model

Systemic sclerosis (SSc) is an immune-mediated systemic autoimmune disease with unknown etiology, which has high morbidity and mortality. Current treatments to dispose of this disorder are limited. And there are still no ideal animal models that can fully replicate the four basic pathophysiological features of SSc, including vascular lesions, fibrosis, inflammation, and autoimmunity, let alone animal models specifically designed to study gastrointestinal lesions. It’s essential to seek and establish appropriate animal models to explore the role of gut microbiota in the pathogenesis of SSc. In this study, we found similar gut microbiota aberration in patients of SSc and bleomycin (BLM)-induced mice model through 16S rRNA gene sequencing. In terms of phylum-level differences, the relative abundance of Bacteroidetes was significantly decreased and Firmicutes increased in the SSc patients and the mice. Notably, the genera of Lactobacillus, commonly used as a probiotic additive, was also elevated in SSc patients and BLM mice, which was consistent with a few of studies. Therefore, the model can likely mimic the pathological changes of gut microbiota in patients with SSc, which may offer an important potential platform for the in-depth understanding of gut microbiota aberration in patients with SSc and to devise potential disease-modifying treatments.

The microbiome and systemic sclerosis: A review of current evidence

Systemic sclerosis (SSc) is characterized by immune dysregulation, vasculopathy, and fibrosis of multiple organs. The gastrointestinal (GI) tract is the most common internal organ manifestation, which contributes to significant morbidity and mortality in patients with SSc. Emerging reports have identified unique microbial taxa alterations in the GI microbiome of patients with SSc as compared to healthy controls (HC). These taxa alterations include differences at the phyla (e.g., Bacteroidetes) and genera (e.g., Bacteroides, Clostridium, Faecalibacterium, and Lactobacillus) level. In addition, some genera have been associated with more severe GI symptoms (e.g., Prevotella and Akkermansia). This review summarizes the current evidence on factors influencing the GI microbiome, GI microbiome alterations in SSc as compared to HC, and in SSc subgroups according to disease manifestations. Current exploration in therapeutic interventions that target the GI microbiome is discussed.

Butyrate Improves Skin/Lung Fibrosis and Intestinal Dysbiosis in Bleomycin-Induced Mouse Models

Systemic sclerosis (SSc) is an autoimmune disorder characterized by fibrosis of the skin and internal organs. Despite several studies on SSc treatments, effective treatments for SSc are still lacking. Since evidence suggests an association between intestinal microbiota and SSc, we focused on butyrate, which has beneficial effects in autoimmune diseases as a bacterial metabolite. Here, we investigated the therapeutic potential of sodium butyrate (SB) using a bleomycin-induced fibrosis mouse model of SSc and human dermal fibroblasts (HDFs). SB attenuated bleomycin-induced dermal and lung fibrosis in mice. SB influenced fecal microbiota composition (phyla Actinobacteria and Bacteroidetes, genera Bifidobacterium and Ruminococcus_g2). SB controlled macrophage differentiation in mesenteric lymph nodes, spleen, and bronchoalveolar lavage cells of mice with bleomycin-induced skin fibrosis. Profibrotic and proinflammatory gene expression was suppressed by SB administration in skin. Furthermore, SB inhibited transforming growth factor β1-responsive proinflammatory expression with increased acetylation of histone 3 in HDFs. Subcutaneous SB application had antifibrogenic effects on the skin. Butyrate ameliorated skin and lung fibrosis by improving anti-inflammatory activity in a mouse model of SSc. Butyrate may exhibit indirect and direct anti-fibrogenic action on fibroblasts by regulating macrophage differentiation and inhibition of histone deacetylase 3. These findings suggest butyrate as an SSc treatment.

Gastrointestinal involvement in systemic sclerosis: Effects on morbidity and mortality and new therapeutic approaches

The majority of research studies in systemic sclerosis focus largely on addressing skin and cardiopulmonary manifestations. Fewer studies assess the pathogenesis and treatment of gastrointestinal tract involvement in systemic sclerosis, despite the fact that the majority of patients with systemic sclerosis have gastrointestinal manifestations and these manifestations are a leading cause of death in systemic sclerosis. The present review provides a comprehensive update on morbidity and mortality outcomes related to gastrointestinal involvement in systemic sclerosis. This review also describes conventional and emerging approaches to managing gastrointestinal symptoms in systemic sclerosis. Recent developments in systemic sclerosis-gastrointestinal research efforts have revealed promising treatment targets, including specific auto-antibodies and microbiota alterations. This review will conclude with an overview of future research directions that may improve our understanding of systemic sclerosis-gastrointestinal involvement and ultimately help to alleviate suffering from this devastating dimension of systemic sclerosis.

Longitudinal Characterisation of the Gastrointestinal Tract Microbiome in Systemic Sclerosis

Objectives

To evaluate changes in microbial composition and the evolution of gastrointestinal tract (GIT) symptoms in systemic sclerosis (SSc).

Methods

Adult SSc patients provided stool specimens every 3 months over the course of 1 year. Participants completed the University of California, Los Angeles (UCLA) GIT 2.0 questionnaire to assess GIT symptom severity at each stool collection. The microbiota from these samples were determined by Illumina HiSeq 2500 16S ribosomal RNA sequencing (Illumina, Inc., San Diego, California, USA). Mixed effect models evaluated changes in GIT symptoms and microbial composition over time.

Results

Among 19 patients with SSc (female; 89.5%; median age: 51.3 years), the median disease duration was 7 years and the baseline total GIT 2.0 score was 0.7 (standard deviation: 0.6). The majority of participants (63%) provided at least four stool samples over the course of the 12-month study. Patients with longer disease durations had increased GIT symptoms over the course of the study. There was no difference in the course of GIT symptoms over time between patients with limited versus diffuse cutaneous disease. The relative abundances of specific genera did not change over time within individual subjects. After controlling for age, sex, ethnicity, disease duration, and SSc subtype (i.e., limited versus diffuse), low abundance of Bacteroides was associated with increased GIT symptoms over time.

Conclusion

This study is the first to have longitudinally characterised the lower GIT microbiome in SSc patients and demonstrated relative stability of genera abundance over the course of 1 year. The findings provide additional evidence that specific genera are associated with SSc-GIT symptoms and warrant further evaluation in larger SSc studies.

Toward Understanding of Environmental Risk Factors in Systemic Sclerosis [Formula: see text]

IMPORTANCE

Systemic sclerosis (SSc) is a severe, chronic, and incurable autoimmune fibrotic skin disease with significant extracutaneous involvement. Low concordance rate in twin studies and unequal geographic distribution of SSc argues for importance of environment in disease initiation and progression.

OBJECTIVE

In this manuscript we provide a summary of all investigated potential external risk factors for SSc.

DATA SOURCES

A literature search in PubMed and EMBASE database was performed for studies published until January 1, 2020 by 2 reviewers (EN and LO) independently.

FINDINGS

Occupational and/or environmental exposures to silica and organic solvents are associated with increased incidence and severity of SSc. Exposure to epoxy resins, asbestos, and particulate air pollution favors increased risk of SSc, but data are based on limited number of observational studies. There is insufficient evidence to conclude an association between SSc development and other occupational (eg, welding fumes) or personal exposures (eg, smoking, vitamin D deficiency). Association of SSc with silicone breast implants has been disproven. Infectious pathogens (eg, Helicobacter pylori and angiotropic viruses) and dysbiosis seem to play a role in SSc development and severity, but their role remains to be clarified.

CONCLUSIONS AND RELEVANCE

It may be prudent to counsel our patients with SSc (or those at risk of SSc) to avoid occupations with exposure to silica, organic solvents, asbestos and epoxy resins; restraint from smoking, using cocaine or drugs with pro-fibrotic potential. While the association between low vitamin D and SSc remains to be confirmed, we believe that SSc patients should be encouraged to maintain healthy vitamin D levels as benefits outweigh the risks.

[Characteristics of intestinal flora in patients with primary Sjögren syndrome]

OBJECTIVE

To investigate changes in intestinal flora in patients with primary Sj?gren syndrome (pSS) and explore the relationship between pSS disease activity and intestinal flora structure.

METHODS

Fecal samples were collected from 18 female pSS patients, including 9 patients with active disease (group A) and 9 with disease inactivity or low activity (group B), with 10 healthy subjects as the control group. The total bacterial DNA was extracted from the fecal samples for PCR amplification, and Illumina Hiseq 2500 high-throughput sequencing was performed for the v3-v4 region of 16Sr DNA gene to obtain the biological information of the intestinal flora. The intergroup OTU analysis, structural diversity analysis, significant difference analysis and LEFSE analysis were performed with information mining of the literature think tanks.

RESULTS

The dilution curves generated based on the OTUshannon index for analysis of sample complexity showed that the measured data were relatively complete and could reflect the diversity of the microorganisms in the subjects. Analysis of the Alpha diversity index showed that the Shannon index differed significantly between group A and group B, and the Simpson index differed significantly between group A and group B and between group A and the control group (P &lt; 0.05). Sequence analysis the 3 groups all consisted mainly of 4 phylum (Firmicutes, Bacteroidetes, Actinobacteria, showed that the intestinal flora in and proteobacteria) and 4 genera (finegoldia, Prevotella, Streptococcus, and Corynebacterium_1), all showing no significant differences among the 3 groups (P &gt; 0.05) with the exception of Streptococcus genus, which differed significantly among the 3 groups (P &lt; 0.05). The 16S v3-v4 region in the genus Alloscardovia, Bacteroides, Barnesiella, Butyricicoccus, Facklamia, Faecalibacterium, Lachnospiraceae_FCS020_group, Lachnospiraceae_ND3007_group, Lachnospiraceae_UCG-001, Lachnospirace, Lachnospirace, Ruminococcaceae_UCG-002, Streptococcus and Coprococcus_1 differed significantly among the 3 groups (P &lt; 0.05). The high-dimensional biometrics and genomic characteristics of the intestinal microorganisms differed significantly among the 3 groups (P &lt; 0.05). According to the size of LDA SCORE (effect size), the core flora in group A included the genera Barnesiellaccae, Aerococcaceae, Family-XIII, Bacteroidaceae, Lachnospiraceae_UCG-001, Barnesiella, Facklamia, Alloscardovia, Faecalibacterium and Bacteroides, as compared with the genera Streptococcaceae, Streptococcus, Coprococcus_1, Ruminococcaceae_ucg-002, Lachnospiraceae_FCS020_group, Lachnospiraceae_ucg-004, Lachnospiraceae_ND3007_group, Lachnospiraceae_ucg-008 and Butyricicoccus in the control group.

CONCLUSIONS

Patients with pSS have significant changes in the diversity of intestinal flora, especially in some specific bacteria in Streptococcu genus and in 16S v3-v4 region of the bacteria. The differences in the core bacteria in the intestinal flora of pSS patients suggest the role of flora structure changes in the pathogenesis of pSS.

Metabolic Profiling of Blood and Urine for Exploring the Functional Role of the Microbiota in Human Health

The quantification of metabolites in blood and urine allows nurses to explore new hypotheses about the microbiome. This review summarizes findings from recent studies with a focus on how the state of the science can influence future nursing research initiatives. Metabolomics can advance nursing research by identifying physiologic/pathophysiologic processes underlying patients' symptoms and can be useful for testing the effects of nursing interventions. To date, metabolomics has been used to study cardiovascular, respiratory, endocrine, autoimmune, and infectious conditions, with research focused on understanding the microbial metabolism of substrates resulting in circulating/excreted biomarkers such as trimethylamine N-oxide. This review provides specific recommendations for the collection of specimens and goals for future studies.

The efficacy and safety of fecal microbiota transplantation in the treatment of systemic sclerosis: A protocol for systematic review and meta analysis

BACKGROUND

Systemic sclerosis (SSc) is 1 of the most complex systemic autoimmune diseases.Accumulating evidence suggests that gut microbiota affect the development and function of the immune system and may play a role in the pathogenesis of autoimmune diseases. This new paradigm raises the possibility that many diseases result, at least partially, from microbiota-related dysfunction. This understanding invites the investigation of fecal microbiota transplantation (FMT) in the treatment of SSc. However, no study has specifically and systematically investigated the efficacy and safety of FMT in the treatment of SSc. Thus, this study will systematically and comprehensively appraise the efficacy and safety of FMT in the treatment of SSc.

METHODS

We will search the following sources without restrictions for date, language, or publication status: PubMed, Web of Science,Cochrane Central Register of Controlled Trials (CENTRAL) Cochrane Library, EMBASE and China National Knowledge Infrastructure. We will apply a combination of Medical Subject Heading (MeSH) and free-text terms incorporating database-specific controlled vocabularies and text words to implement search strategies. We will also search the ongoing trials registered in the World Health Organization's International Clinical Trials Registry Platform. Besides, the previous relevant reviews conducted on FMT for SSc and reference lists of included studies will also be searched.

RESULTS

This study will provide a reliable basis for the treatment of SSc with FMT.

CONCLUSIONS

The findings will be an available reference to evaluate the efficacy and safety of FMT in the treatment of SSc.

REGISTRATION NUMBER

INPLASY202060019.

Dysregulation of gut microbiome is linked to disease activity of rheumatic diseases

Objective rheumatism refers to a large group of diseases with different etiology, mainly characterized by autoimmune disorder. Intestinal flora combines with the digestive organs of the human body to synthesize and secrete the key substances of growth. Several studies have reported abnormal intestinal flora in rheumatic diseases. The purposes of this research were to review the primary studies and figure out the relationship between intestinal flora and rheumatic disease activity. The article search was based on the database of PubMed (MEDLINE), EMBASE, Cochrane to collect English language studies that were published from 1985 to 2019. The articles concerning the intestinal flora and disease activities of rheumatic diseases were classified by disease types, and the relationship between disease activities and intestinal flora was summarized. Eight rheumatic diseases were included in the study. It was found that the changes of intestinal flora were significantly correlated with the activities of rheumatic diseases. There were significant differences in the classification of disease activity and the composition of intestinal flora. Interfering with the composition of intestinal flora can apparently modulate the development of disease. But how to apply such findings is rarely reported. The study finds out that intestinal flora disorder is linked to the activity of rheumatic diseases. But which specific gut flora is connected to the disease activity needs further researches. More discussion is needed on how to apply the results to clinical treatment.

Microbiota and metabolites in rheumatic diseases

As a gigantic community in the human body, the microbiota exerts pleiotropic roles in human health and disease ranging from digestion and absorption of nutrients from food, defense against infection of pathogens, to regulation of immune system development and immune homeostasis. Recent advances in "omics" studies and bioinformatics analyses have broadened our insights of the microbiota composition of the inner and other surfaces of the body and their interactions with the host. Apart from the direct contact of microbes at the mucosal barrier, metabolites produced or metabolized by the gut microbes can serve as important immune regulators or initiators in a wide variety of diseases, including gastrointestinal diseases, metabolic disorders and systemic rheumatic diseases. This review focuses on the most recent understanding of how the microbiota and metabolites shape rheumatic diseases. Studies that explore the mechanistic interplay between microbes, metabolites and the host could thereby provide clues for novel methods in the diagnosis, therapy, and prevention of rheumatic diseases.

Gastrointestinal tract microbiota modifications in systemic sclerosis

Systemic sclerosis (SSc) is a complex autoimmune disease of unknown etiology. Genetic factors are thought to collude with various environmental triggers to induce SSc and subsequently manifest various SSc disease phenotypes. Emerging evidence suggests that the microbiota of the gastrointestinal tract (GIT) may represent a key pathogenic participant in this disease state. Recent studies have demonstrated specific alterations in the GIT microbial composition in SSc patients, and this article reviews studies that have investigated the GIT microbiota in SSc patients. The focus of this article is to highlight the modifications in the GIT microbiota observed in SSc patients belonging to different cohorts and to demonstrate how these alterations may be associated with specific SSc features. This article presents the results of these SSc microbiota studies in the context of findings from microbiotic studies in other autoimmune states to explore similarities and differences across disease states affecting the immune system. Finally, this article provides insights into potential SSc therapies that target the GIT microbiota. Given the complexity and variability of the SSc disease state, any treatment aimed at modulating GIT microbiota will likely need to be coupled with additional interventions that target other SSc disease components.

Gastrointestinal involvement in systemic sclerosis: an update

PURPOSE OF REVIEW

This review provides important updates in systemic sclerosis (SSc)-related gastrointestinal disease, specifically focusing on the most recent literature.

RECENT FINDINGS

In the past year, several studies were published that present interesting insights into SSc and gastrointestinal disease. Studies focusing on newly identified risk factors, novel approaches to diagnosis and assessment of disease activity, survival and quality of life demonstrate progress in our understanding of this challenging area. Additional data on specific SSc gastrointestinal-related topics, such as the link between gastrointestinal and pulmonary disease, nutrition, and the microbiome, are also now available.

SUMMARY

SSc gastrointestinal disease is heterogeneous in its clinical presentation, which presents a challenge in diagnosis and management. In the past year, several studies have evaluated risk factors and clinical features associated with specific gastrointestinal complications in SSc. Objective gastrointestinal testing may help to identify specific SSc gastrointestinal subgroups and provide diagnostic accuracy to guide targeted therapies. Survival in very early SSc is affected by the severity of gastrointestinal involvement. Other important gastrointestinal subsets, including patients with esophageal disease and interstitial lung disease, should carefully be considered when developing a management plan for this patient population.

Identification of a Shared Microbiomic and Metabolomic Profile in Systemic Autoimmune Diseases

Dysbiosis has been described in systemic autoimmune diseases (SADs), including systemic lupus erythematosus (SLE), Sjögren’s syndrome (SjS), and primary anti-phosholipid syndrome (PAPS), however the biological implications of these associations are often elusive. Stool and plasma samples from 114 subjects, including in SLE (n = 27), SjS (n = 23), PAPs (n = 11) and undifferentiated connective tissue (UCTD, n = 26) patients, and geographically-matched healthy controls (HCs, n = 27), were collected for microbiome (16s rRNA gene sequencing) and metabolome (high-performance liquid chromatography coupled to mass spectrometry) analysis to identify shared characteristics across diseases. Out of 130 identified microbial genera, a subset of 29 bacteria was able to differentiate study groups (area under receiver operating characteristics (AUROC) = 0.730 ± 0.025). A fair classification was obtained with a subset of 41 metabolic peaks out of 254 (AUROC = 0.748 ± 0.021). In both models, HCs were well separated from SADs, while UCTD largely overlapped with the other diseases. In all of the SADs pro-tolerogenic bacteria were reduced, while pathobiont genera were increased. Metabolic alterations included two clusters comprised of: (a) members of the acylcarnitine family, positively correlating with a Prevotella-enriched cluster and negatively correlating with a butyrate-producing bacteria-enriched cluster; and (b) phospholipids, negatively correlating with butyrate-producing bacteria. These findings demonstrate a strong interaction between intestinal microbiota and metabolic function in patients with SADs.

Update on the Gastrointestinal Microbiome in Systemic Sclerosis

PURPOSE OF REVIEW

Accumulating evidence suggests that gut microbiota affect the development and function of the immune system and may play a role in the pathogenesis of autoimmune diseases. The purpose of this review is to summarize recent studies reporting gastrointestinal microbiota aberrations associated with the systemic sclerosis disease state.

RECENT FINDINGS

The studies described herein have identified common changes in gut microbial composition. Specifically, patients with SSc have decreased abundance of beneficial commensal genera (e.g., Faecalibacterium, Clostridium, and Bacteroides) and increased abundance of pathobiont genera (e.g., Fusobacterium, Prevotella, Erwinia). In addition, some studies have linked specific genera with the severity of gastrointestinal symptoms in systemic sclerosis. More research is needed to further characterize the gastrointestinal microbiota in systemic sclerosis and understand how microbiota perturbations can affect inflammation, fibrosis, and clinical outcomes. Interventional studies aimed at addressing/correcting these perturbations, either through dietary modification, pro/pre-biotic supplementation, or fecal transplantation, may lead to improved outcomes for patients with systemic sclerosis.