Intestinal microbiota and juvenile idiopathic arthritis: current understanding and future prospective

Interplay of gut microbiota in Kawasaki disease: role of gut microbiota and potential treatment strategies

Kawasaki disease (KD) is an acute systemic immune vasculitis with predominant involvement of the medium and small arteries. It mostly affects pediatric patients, representing the most common form of pediatric vasculitis in children less than 5 years old. Numerous diseases, especially those related to the immune system, have established links with the intestinal flora. Recent studies have investigated the intestinal flora changes throughout the management of KD. There was gut microbiota dysbiosis in pediatric KD at the acute phase, particularly the downregulation of short-chain fat acids-producing microbiota and the over-proliferation of opportunistic pathogens. The relationship between the response to therapies in individuals with KD and specific microbiota remains uncertain. Targeted microbial supplements and dietary regulation may serve as potential measures to alleviate KD complications and thus improve prognosis. This review provides an overview of the current understanding of the interplay of the gut microbiota and KD. Furthermore, it discusses the possibility of altering the gut microbiota to reinstate a healthy condition.

Causal association of juvenile idiopathic arthritis or JIA-associated uveitis and gut microbiota: a bidirectional two-sample Mendelian randomisation study

Background

The gut microbiota significantly influences the onset and progression of juvenile idiopathic arthritis (JIA) and associated uveitis (JIAU); however, the causality remains unclear. This study aims to establish a causal link between gut microbiota and JIA or JIAU.

Methods

Using publicly available genome-wide association studies (GAWS) summary data, we conducted a two-sample Mendelian randomisation (MR) analysis employing various methods, namely inverse variance weighted (IVW), simple mode, weighted mode, weighted median and MR-Egger regression methods, to assess the causal association between JIA or JIAU and gut microbiota. Sensitivity analyses, including Cochrane's Q test, MR-Egger intercept test, leave-one-out analysis and MR-PRESSO, were performed to evaluate the robustness of the MR results. Subsequently, reverse MR analysis was conducted to determine causality between gene-predicted gut microbiota abundance and JIA or JIAU.

Results

The MR analysis revealed a causal association between gut microbiota abundance variations and JIA or JIAU risk. Specifically, the increased abundance of genus Ruminococcaceae UCG013 (OR: 0.055, 95%CI: 0.006-0.103, p = 0.026) and genus Ruminococcaceae UCG003 (β: 0.06, 95%CI: 0.003-0.117, p = 0.041) correlated with an increased risk of JIA, while genus Lachnospiraceae UCG001 (OR: 0.833, 95%CI: 0.699~0.993, p = 0.042) was associated with a reduced risk of JIA, among others. Sensitivity analysis confirmed MR analysis robustness.

Conclusions

This study provides substantial evidence supporting a causal association between genetically predicted gut microbiota and JIA or JIAU. It highlights the significant role of intestinal flora in JIA or JIAU development, suggesting their potential as novel biomarkers for diagnosis and prevention. These findings offer valuable insights to mitigate the impact of JIA or JIAU.

Association of Infant Breastfeeding and Juvenile Spondyloarthritis: A Case-Control Study

OBJECTIVE

Given the multifactorial pathogenesis of juvenile spondyloarthritis (JSpA) and evidence of a protective effect in phenotypically similar diseases, we aimed to test whether breastfeeding is associated with the development and disease activity of JSpA.

METHODS

This single-center retrospective case-control study included children with JSpA and age- and sex-matched controls with a 1:1 ratio. Univariable and multivariable conditional logistic regression modeling for matched pairs was used to test the association of infant factors with the development of JSpA, including infant nutrition and form of delivery. Linear regression was used to assess the association of JSpA disease activity (JSpA Disease Activity Index with 6 elements [JSpADA6]) at presentation with breastfeeding exposure, form of delivery, and antibiotic exposure.

RESULTS

For the 195 case-control matched pairs, the mean age was 13.0 years and 47.7% were female. For breastfeeding, 88.7% of controls and 69.2% of JSpA cases were exposed to breastfeeding of any duration, respectively (P < 0.001). In the multivariable model, exclusive breastfeeding > 6 months was independently and significantly associated with a lower chance of JSpA development (odds ratio 0.47, 95% CI 0.30-0.72; P < 0.001). The median JSpADA6 was not significantly associated with breastfeeding for > 6 months. However, vaginal delivery was significantly associated with a lower JSpADA6 (B = -0.65, 95% CI -1.13 to -0.17; P = 0.008).

CONCLUSION

This study suggests that infant factors that affect the microbiome may be associated with the occurrence and disease activity of JSpA at presentation.

Relationships among gut microbiota, plasma metabolites, and juvenile idiopathic arthritis: a mediation Mendelian randomization study

Objective

The objective of this study is to investigate the causal relationship between gut microbiota and juvenile idiopathic arthritis, and to identify and quantify the potential role of plasma metabolites as mediators.

Methods

Using summary-level data from genome-wide association studies, a two-sample Mendelian randomization was conducted involving 131 gut microbiota genus, 1,400 plasma metabolites, and juvenile idiopathic arthritis. Additionally, a two-step approach was employed to quantify the proportion of the effect of gut microbiota on juvenile idiopathic arthritis mediated by plasma metabolites. Effect estimation primarily utilized Inverse Variance Weighting, with further validation using Bayesian weighted Mendelian randomization.

Results

In our MR analysis, a positive correlation was observed between Rikenellaceae and the risk of juvenile idiopathic arthritis, while Dorea showed a negative correlation with juvenile idiopathic arthritis risk. Mediation analysis indicated that Furaneol sulfate levels acted as a mediator between Dorea and juvenile idiopathic arthritis, with an indirect effect proportion of 19.94, 95% CI [8.86-31.03%].

Conclusion

Our study confirms a causal relationship between specific microbial genus and juvenile idiopathic arthritis, and computes the proportion of the effect mediated by plasma metabolites, offering novel insights for clinical interventions in juvenile idiopathic arthritis.

Efficacy and safety of gut microbiota-based therapies in autoimmune and rheumatic diseases: a systematic review and meta-analysis of 80 randomized controlled trials

BACKGROUND

Previous randomized controlled trials (RCTs) suggested that gut microbiota-based therapies may be effective in treating autoimmune diseases, but a systematic summary is lacking.

METHODS

Pubmed, EMbase, Sinomed, and other databases were searched for RCTs related to the treatment of autoimmune diseases with probiotics from inception to June 2022. RevMan 5.4 software was used for meta-analysis after 2 investigators independently screened literature, extracted data, and assessed the risk of bias of included studies.

RESULTS

A total of 80 RCTs and 14 types of autoimmune disease [celiac sprue, SLE, and lupus nephritis (LN), RA, juvenile idiopathic arthritis (JIA), spondyloarthritis, psoriasis, fibromyalgia syndrome, MS, systemic sclerosis, type 1 diabetes mellitus (T1DM), oral lichen planus (OLP), Crohn's disease, ulcerative colitis] were included. The results showed that gut microbiota-based therapies may improve the symptoms and/or inflammatory factor of celiac sprue, SLE and LN, JIA, psoriasis, PSS, MS, systemic sclerosis, Crohn's disease, and ulcerative colitis. However, gut microbiota-based therapies may not improve the symptoms and/or inflammatory factor of spondyloarthritis and RA. Gut microbiota-based therapies may relieve the pain of fibromyalgia syndrome, but the effect on fibromyalgia impact questionnaire score is not significant. Gut microbiota-based therapies may improve HbA1c in T1DM, but its effect on total insulin requirement does not seem to be significant. These RCTs showed that probiotics did not increase the incidence of adverse events.

CONCLUSIONS

Gut microbiota-based therapies may improve several autoimmune diseases (celiac sprue, SLE and LN, JIA, psoriasis, fibromyalgia syndrome, PSS, MS, T1DM, Crohn's disease, and ulcerative colitis).

Antibiotic exposure in prenatal and early life and risk of juvenile idiopathic arthritis: a nationwide register-based cohort study

OBJECTIVES

Early antibiotic exposure influences the gut microbiota which is believed to be involved in the pathogenesis of juvenile idiopathic arthritis (JIA). We aimed to investigate the association between systemic antibiotics in prenatal and early life and risk of JIA.

METHODS

We conducted a register-based cohort study including all children born in Norway from 2004 through 2012. The children were followed until 31 December 2020. Main exposures were dispensed antibiotics to the mother during pregnancy and to the child during 0-24 months of age. The outcome was defined by diagnostic codes indicating JIA. Multivariate logistic regression analyses were performed to estimate the association between antibiotic exposure and JIA.

RESULTS

We included 535 294 children and their mothers in the analyses; 1011 cases were identified. We found an association between exposure to systemic antibiotics during 0-24 months and JIA (adjusted OR (aOR) 1.40, 95% CI 1.24 to 1.59), with a stronger association for >1 course (aOR 1.50, 95% CI 1.29 to 1.74) vs 1 course (aOR 1.31, 95% CI 1.13 to 1.53). Subanalyses showed significant associations in all age periods except 0-6 months, and stronger association with sulfonamides/trimethoprim and broad-spectrum antibiotics. There was no association between prenatal antibiotic exposure and JIA.

CONCLUSIONS

The novel observation of no association with prenatal antibiotic exposure and JIA suggests that the association between antibiotics in early life and JIA is unlikely to be confounded by shared family factors. This may indicate that exposure to antibiotics in early life is an independent risk factor for JIA.

Juvenile idiopathic arthritis and its associated uveitis

INTRODUCTION

Juvenile idiopathic arthritis is the most common chronic rheumatologic disease in children. Uveitis is the most common extra-articular manifestation of JIA, and it can be a sight-threatening condition.

AREAS COVERED

In this review article, we discussed epidemiology, risk factors, clinical presentation, supportive laboratory tests, treatment options, and complications of Juvenile idiopathic arthritis and Juvenile idiopathic arthritis associated uveitis. We covered conventional immunomodulatory therapy and biologic response modifiers agents for different types of Juvenile idiopathic arthritis and their associated uveitis. Finally, we discussed the course of disease, functional outcome, and the quality of life of Juvenile idiopathic arthritis and Juvenile idiopathic arthritis-associated uveitis.

EXPERT OPINION

Although clinical outcomes of Juvenile idiopathic arthritis and its associated uveitis have been improved over the past three decades by biologic response modifier agents, a significant proportion of patients require active treatment into adult life therefore screening and monitoring of these patients is required during the patient's entire life. The limited number of food and drug administration approved biologic response modifier agents for the treatment of Juvenile idiopathic arthritis associated uveitis justify more randomized clinical trials with new medications in this field.

Research progress of single-cell transcriptome sequencing in autoimmune diseases and autoinflammatory disease: A review

Autoimmunity refers to the phenomenon that the body's immune system produces antibodies or sensitized lymphocytes to its own tissues to cause an immune response. Immune disorders caused by autoimmunity can mediate autoimmune diseases. Autoimmune diseases have complicated pathogenesis due to the many types of cells involved, and the mechanism is still unclear. The emergence of single-cell research technology can solve the problem that ordinary transcriptome technology cannot be accurate to cell type. It provides unbiased results through independent analysis of cells in tissues and provides more mRNA information for identifying cell subpopulations, which provides a novel approach to study disruption of immune tolerance and disturbance of pro-inflammatory pathways on a cellular basis. It may fundamentally change the understanding of molecular pathways in the pathogenesis of autoimmune diseases and develop targeted drugs. Single-cell transcriptome sequencing (scRNA-seq) has been widely applied in autoimmune diseases, which provides a powerful tool for demonstrating the cellular heterogeneity of tissues involved in various immune inflammations, identifying pathogenic cell populations, and revealing the mechanism of disease occurrence and development. This review describes the principles of scRNA-seq, introduces common sequencing platforms and practical procedures, and focuses on the progress of scRNA-seq in 41 autoimmune diseases, which include 9 systemic autoimmune diseases and autoinflammatory diseases (rheumatoid arthritis, systemic lupus erythematosus, etc.) and 32 organ-specific autoimmune diseases (5 Skin diseases, 3 Nervous system diseases, 4 Eye diseases, 2 Respiratory system diseases, 2 Circulatory system diseases, 6 Liver, Gallbladder and Pancreas diseases, 2 Gastrointestinal system diseases, 3 Muscle, Bones and joint diseases, 3 Urinary system diseases, 2 Reproductive system diseases). This review also prospects the molecular mechanism targets of autoimmune diseases from the multi-molecular level and multi-dimensional analysis combined with single-cell multi-omics sequencing technology (such as scRNA-seq, Single cell ATAC-seq and single cell immune group library sequencing), which provides a reference for further exploring the pathogenesis and marker screening of autoimmune diseases and autoimmune inflammatory diseases in the future.

Sex-specific gut microbiome profiles among preterm infants during the neonatal intensive care hospitalization

Objectives

The gut microbiota among preterm infants is shaped by sex and feeding types. However, sex-specific weekly patterns of gut microbiome profiles among preterm infants during their neonatal intensive care unit (NICU) hospitalization remain unclear. This study aimed to investigate the effect of sex on the weekly development of preterm neonatal gut microbiota in the first 4 weeks of NICU hospitalization.

Methods

This secondary data analysis included 28 preterm neonates with 261 stool samples collected from January 2014 to February 2015 in the Northeastern United States. The 16S rRNA V4 gene regions of the stool samples were sequenced and aligned against the SILVA 132 database by using Mothur 1.42.3. The sex-specific weekly diversity indexes and relative abundance of bacterial taxonomic composition were generated by Mothur and analyzed by R packages. Sex-specific weekly compositional patterns of the gut microbiome and predicted metabolic functions of gut microbiome profiles were compared, respectively.

Results

In each week of the NICU hospitalization, preterm females and males had significantly distinguished β-diversity indices and compositions of gut microbiota. Both females and males had significantly enriched Bifidobacterium, a protection feature, in stool samples collected in the third week compared with those in the second week. The predicted metabolic pathways were significantly different between females and males in the second, third, and fourth week of the NICU hospitalization. Both females and males had significantly abundant pathways. Males consistently had more abundance of "lipopolysaccharide biosynthesis" than females in the second, third, and fourth week. Males also had a significant abundance of "membrane and intracellular structural molecules" and "glycan biosynthesis and metabolism" in the second and third week.

Conclusions

Sex shaped the weekly patterns of preterm neonatal gut microbiome profiles during the first 4 weeks of the NICU hospitalization. Further clinical interventions should consider the distinct gut microbiota compositions and predicted functional profiles between female and male preterm neonates.

B Cells on the Stage of Inflammation in Juvenile Idiopathic Arthritis: Leading or Supporting Actors in Disease Pathogenesis?

Juvenile idiopathic arthritis (JIA) is a term that collectively refers to a group of chronic childhood arthritides, which together constitute the most common rheumatic condition in children. The International League of Associations for Rheumatology (ILAR) criteria define seven categories of JIA: oligoarticular, polyarticular rheumatoid factor (RF) negative (RF-), polyarticular RF positive (RF+), systemic, enthesitis-related arthritis, psoriatic arthritis, and undifferentiated arthritis. The ILAR classification includes persistent and extended oligoarthritis as subcategories of oligoarticular JIA, but not as distinct categories. JIA is characterized by a chronic inflammatory process affecting the synovia that begins before the age of 16 and persists at least 6 weeks. If not treated, JIA can cause significant disability and loss of quality of life. Treatment of JIA is adjusted according to the severity of the disease as combinations of non-steroidal anti-inflammatory drugs (NSAIDs), synthetic and/ or biological disease modifying anti-rheumatic drugs (DMARDs). Although the disease etiology is unknown, disturbances in innate and adaptive immune responses have been implicated in JIA development. B cells may have important roles in JIA pathogenesis through autoantibody production, antigen presentation, cytokine release and/ or T cell activation. The study of B cells has not been extensively explored in JIA, but evidence from the literature suggests that B cells might have indeed a relevant role in JIA pathophysiology. The detection of autoantibodies such as antinuclear antibodies (ANA), RF and anti-citrullinated protein antibodies (ACPA) in JIA patients supports a breakdown in B cell tolerance. Furthermore, alterations in B cell subpopulations have been documented in peripheral blood and synovial fluid from JIA patients. In fact, altered B cell homeostasis, B cell differentiation and B cell hyperactivity have been described in JIA. Of note, B cell depletion therapy with rituximab has been shown to be an effective and well-tolerated treatment in children with JIA, which further supports B cell intervention in disease development.

Juvenile idiopathic arthritis

Juvenile idiopathic arthritis (JIA) is an umbrella term for arthritis of unknown origin, lasting for >6 weeks with onset before 16 years of age. JIA is the most common chronic inflammatory rheumatic condition of childhood. According to the International League Against Rheumatism (ILAR) classification, seven mutually exclusive categories of JIA exist based on disease manifestations during the first 6 months of disease. Although the ILAR classification has been useful to foster research, it has been criticized mainly as it does not distinguish those forms of chronic arthritis observed in adults and in children from those that may be unique to childhood. Hence, efforts to provide a new evidence-based classification are ongoing. Similar to arthritis observed in adults, pathogenesis involves autoimmune and autoinflammatory mechanisms. The field has witnessed a remarkable improvement in therapeutic possibilities of JIA owing to the availability of new potent drugs and the possibility to perform controlled trials with support from legislative interventions and large networks availability. The goal of drug therapy in JIA is to rapidly reduce disease activity to inactive disease or clinical remission, minimize drug side effects and achieve a quality of life comparable to that of healthy peers. As JIA can influence all aspects of a child's and their family's life, researchers increasingly recognize improvement of health-related quality of life as a key treatment goal.

Immunopathophysiology of Juvenile Spondyloarthritis (jSpA): The "Out of the Box" View on Epigenetics, Neuroendocrine Pathways and Role of the Macrophage Migration Inhibitory Factor (MIF)

Juvenile spondyloarthritis (jSpA) is a an umbrella term for heterogeneous group of related seronegative inflammatory disorders sharing common symptoms. Although it mainly affects children and adolescents, it often remains active during adulthood. Genetic and environmental factors are involved in its occurrence, although the exact underlying immunopathophysiology remains incompletely elucidated. Accumulated evidence suggests that, in affected patients, subclinical gut inflammation caused by intestinal dysbiosis, is pivotal to the future development of synovial-entheseal complex inflammation. While the predominant role of IL17/23 axis, TNF-α, and IL-7 in the pathophysiology of SpA, including jSpA, is firmly established, the role of the cytokine macrophage migration inhibitory factor (MIF) is generally overlooked. The purpose of this review is to discuss and emphasize the role of epigenetics, neuroendocrine pathways and the hypothalamic-pituitary (HPA) axis, and to propose a novel hypothesis of the role of decreased NLRP3 gene expression and possibly MIF in the early phases of jSpA development. The decreased NLRP3 gene expression in the latter, due to hypomethylation of promotor site, is (one of) the cause for inflammasome malfunction leading to gut dysbiosis observed in patients with early jSpA. In addition, we highlight the role of MIF in the complex innate, adaptive cellular and main effector cytokine network, Finally, since treatment of advanced bone pathology in SpA remains an unmet clinical need, I suggest possible new drug targets with the aim to ultimately improve treatment efficacy and long-term outcome of jSpA patients.

Nutri-epigenetics: the effect of maternal diet and early nutrition on the pathogenesis of autoimmune diseases

Autoimmune diseases comprise a wide group of diseases involving a self-response of the immune system against the host. The etiopathogenesis is very complex involving disease-specific factors but also environmental factors, among which the diet. Maternal diet during pregnancy as well as early nutrition recently attracted the interest of the scientists as contributing to the immune programming. In this paper, we reviewed the most recent literature on the effect of maternal diet and early nutrition in modulating the immune system in a selected subset of autoimmune diseases: type 1 diabetes, celiac disease, inflammatory bowel disease, juvenile idiopathic arthritis and rheumatoid arthritis. Particularly, we focused our narrative on the role of maternal and perinatal nutrition in the epigenetic mechanisms underlying the auto-immune response. Maternal diet during pregnancy as well as breastfeeding and early nutrition play a big role in many epigenetic mechanisms. Most of the nutrients consumed by the mother and the infant are known exerting epigenetic functions, such as folate, methionine, zinc, vitamins B12 and D, fibers, casein and gliadin, and they were linked to gene expression changes in the immune pathways. Despite the common role of maternal diet, breastfeeding and early nutrition in almost all the autoimmune diseases, each disease seems to have specific diet-driver epigenetic mechanisms that require further investigations. The research in this field is opening new routes to establishing a precision nutrition approach to the auto-immune diseases.