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

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

Microbiota-dependent indole production is required for the development of collagen-induced arthritis.

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

Impact of the COVID-19 Pandemic on Early Career Investigators in Rheumatology: Recommendations to Address Challenges to Early Research Careers.

OBJECTIVE: The COVID-19 pandemic has impacted the careers of trainees and early career investigators (ECIs). We sought to assess how the American College of Rheumatology (ACR) and the Rheumatology Research Foundation (RRF) can address the needs of those pursuing research careers. METHODS: The Committee on Research created a survey to assess the impact of COVID-19 and identify topics for the ACR and the RRF to address. In fall of 2020, we surveyed postdoctoral trainees and ECIs within 9 years of terminal training. Responses were analyzed using descriptive statistics and qualitative content analysis. RESULTS: Twenty-one percent of invitees responded to the survey (n = 365); of these, 60% were pursuing careers in academic research. Seventy-five percent of respondents in academic research career paths placed their primary projects on hold during the pandemic. The number of individuals pursuing a research career from 2020 to 2021 decreased by 5%. Respondents reported funding, caregiving, and lack of preliminary data as significant challenges. Suggested impactful interventions included increased funding, funding process reform, and expanding mentoring and networking resources. CONCLUSION: Major stressors identified during the pandemic included increased caregiving responsibilities and difficulty obtaining data and funding, for which respondents suggested increases and changes in funding programs as well as more mentoring and networking opportunities. Based on these, the Committee on Research proposes 3 priorities: 1) flexible funding mechanisms for ECIs and additional support for those impacted by caregiving; 2) virtual and in-person programs for career development and networking; and 3) curated content relevant to building a research career available on demand.

Novel Biomarker of Collagen Degradation Can Identify Patients Affected With Both Axial Spondyloarthritis and Crohn Disease.

OBJECTIVE: Chronic inflammatory arthritis is a hallmark of axial spondyloarthritis (axSpA), where coexistence of Crohn disease (CD) is prominent. We investigated the association between biomarkers of collagen degradation in healthy controls (HCs) and in patients with axSpA, CD, and CD and axSpA overlap (CD-axSpA), with the aim to investigate the ability of the biomarkers to identify patients with CD-axSpA. METHODS: Patients with axSpA who fulfilled Assessment of Spondyloarthritis international Society criteria (n = 13), had biopsy-proven CD (n = 14), had CD-axSpA (n = 10), and HCs (n = 11) undergoing standard-of-care colonoscopies were included in the study. The collagen biomarkers measuring type III, IV, VI and X collagen (C3M, C4M, C6M, and C10C, respectively) were measured in plasma samples from all subject groups. Statistical analysis was performed using an ANCOVA adjusted for age, an area under the receiver-operating characteristic (AUROC) curve analysis, and Spearman correlation. RESULTS: C4M was significantly higher in patients with CD-axSpA overlap compared to axSpA, CD, and HCs (all P < 0.001). In an AUROC analysis, C4M showed a complete separation between the patients with CD-axSpA overlap compared to HC, axSpA and CD with an area under the curve (AUC) = 1.00 (P < 0.001). No differences were found between the patient groups for C3M, C6M, and C10C. No correlations were found between the collagen biomarkers and C-reactive protein, Bath Ankylosing Spondylitis Disease Activity Index, Simple Clinical Colitis Activity Index, or Harvey-Bradshaw Index scores. CONCLUSION: Degradation of type IV collagen quantified by C4M showed a complete separation of patients with CD-axSpA overlap, compared to axSpA, CD, and HCs, and indicates excessive collagen degradation and epithelial turnover. This biomarker could potentially be used to identify patients affected by both manifestations and to guide treatment decisions.

A Novel Approach toward Less Invasive Multiomics Gut Analyses: a Pilot Study.

Newer 'omics approaches, such as metatranscriptomics and metabolomics, allow functional assessments of the interaction(s) between the gut microbiome and the human host. However, in order to generate meaningful data with these approaches, the method of sample collection is critical. Prior studies have relied on expensive and invasive means toward sample acquisition, such as intestinal biopsy, while other studies have relied on easier methods of collection, such as fecal samples that do not necessarily represent those microbes in contact with the host. In this pilot study, we attempt to characterize a novel, minimally invasive method toward sampling the human microbiome using mucosal cytology brush sampling compared to intestinal gut biopsy samples on 5 healthy participants undergoing routine screening colonoscopy. We compared metatranscriptomic analyses between the two collection methods and identified increased taxonomic evenness and beta diversity in the cytology brush samples and similar community transcriptional profiles between the two methods. Metabolomics assessment demonstrated striking differences between the two methods, implying a difference in bacterial-derived versus human-absorbed metabolites. Put together, this study supports the use of microbiome sampling with cytology brushes, but caution must be exercised when performing metabolomics assessment, as this represents differential metabolite production but not absorption by the host. IMPORTANCE In order to generate meaningful metabolomic and microbiome data, the method of sample collection is critical. This study utilizes and compares two methods for intestinal tissue collection for evaluation of metabolites and microbiomes, finding that using a brush to sample the microbiome provides valuable data. However, for metabolomics assessment, biopsy samples may still be required.

Student-run Clinic Effect on Emergency Department Utilization (SCEEDU): An Analysis of the DAWN Clinic Impact in Colorado.

BACKGROUND: Student-run free clinics (SRFCs) provide care to medically underserved individuals who may otherwise utilize the emergency department (ED) for primary care. OBJECTIVE: Evaluate the effect of enrollment at the DAWN SRFC in Aurora, Colorado on University of Colorado ED utilization. METHODS: Th is was a retrospective longitudinal analysis of 164 patients who established care at the DAWN clinic and were also seen at the nearby ED over an eight-year period. A paired t-test was used on the full cohort and a linear mixed effects model was used on a guaranteed at-risk subset with ED visits before and aft er care initiation at the DAWN clinic. RESULTS: Average ED visits decreased from 1.48 to 0.95 for the full cohort (p=.0002). In the guaranteed at-risk subset, a 0.98 visit decrease per person (p=.0217) was observed. CONCLUSIONS: Patient enrollment at the DAWN clinic was associated with a statistically significant reduction in all-cause ED visits.

Circulating mature granzyme B+ T cells distinguish Crohn's disease-associated axial spondyloarthritis from axial spondyloarthritis and Crohn's disease.

BACKGROUND: Axial spondyloarthritis (axSpA) has strong connections with intestinal inflammation as occurs in Crohn's disease (CD). However, the immunologic mechanisms that distinguish axSpA, CD, and those with features of both diseases (CD-axSpA) are unknown. This study aimed to address this question by initial unbiased single cell RNA-sequencing (scRNAseq) on a pilot cohort followed by validating findings using flow cytometry and ELISA in a larger cohort. METHODS: Two individuals each with CD, axSpA, CD-axSpA, and healthy controls (HC) were recruited for a pilot discovery scRNAseq cohort, and the validation cohort consisted of 18 axSpA, 24 CD, 13 CD-axSpA, and 17 HC that was evaluated by flow cytometry on PBMCs and ELISAs for plasma cytokines. RESULTS: Uniquely, PBMCs from subjects with CD-axSpA demonstrated a significant increase in granzyme B+ T cells of both CD4+ and CD8+ lineages by both scRNAseq and flow cytometry. T cell maturation was also greater in those with CD-axSpA, particularly the CD4+ granzyme B+ population. Pathway analysis suggested increased interferon response genes in all immune cell populations within CD-axSpA. Although IFN-γ was elevated in the plasma of a subset of subjects with CD-axSpA, IL-6 was also significantly elevated. CONCLUSIONS: Our findings support the presence of a chronic interferonopathy in subjects with CD-axSpA characterized by interferon signaling by pathway analysis and an expansion of mature, cytotoxic T cells. These data indicate fundamental immunological differences between CD-axSpA and both of the putative "parent" conditions, suggesting that it is a distinct disease with unique natural history and treatment needs.

Multi 'Omics Analysis of Intestinal Tissue in Ankylosing Spondylitis Identifies Alterations in the Tryptophan Metabolism Pathway.

Intestinal microbial dysbiosis, intestinal inflammation, and Th17 immunity are all linked to the pathophysiology of spondyloarthritis (SpA); however, the mechanisms linking them remain unknown. One potential hypothesis suggests that the dysbiotic gut microbiome as a whole produces metabolites that influence human immune cells. To identify potential disease-relevant, microbiome-produced metabolites, we performed metabolomics screening and shotgun metagenomics on paired colon biopsies and fecal samples, respectively, from subjects with axial SpA (axSpA, N=21), Crohn's disease (CD, N=27), and Crohn's-axSpA overlap (CD-axSpA, N=12), as well as controls (HC, N=24). Using LC-MS based metabolomics of 4 non-inflamed pinch biopsies of the distal colon from subjects, we identified significant alterations in tryptophan pathway metabolites, including an expansion of indole-3-acetate (IAA) in axSpA and CD-axSpA compared to HC and CD and indole-3-acetaldehyde (I3Ald) in axSpA and CD-axSpA but not CD compared to HC, suggesting possible specificity to the development of axSpA. We then performed shotgun metagenomics of fecal samples to characterize gut microbial dysbiosis across these disease states. In spite of no significant differences in alpha-diversity among the 4 groups, our results confirmed differences in gene abundances of numerous enzymes involved in tryptophan metabolism. Specifically, gene abundance of indolepyruvate decarboxylase, which generates IAA and I3Ald, was significantly elevated in individuals with axSpA while gene abundances in HC demonstrated a propensity towards tryptophan synthesis. Such genetic changes were not observed in CD, again suggesting disease specificity for axSpA. Given the emerging role of tryptophan and its metabolites in immune function, altogether these data indicate that tryptophan metabolism into I3Ald and then IAA is one mechanism by which the gut microbiome potentially influences the development of axSpA.

Mechanical Shock During Shipping of Medications: The Roles of Packaging and Transportation Vendors.

Protein-based medications are expensive and susceptible to damage from mechanical shock, which may occur during shipping to patients from pharmacies. Our objectives were to evaluate the performance of 2 packaging systems and to describe the mechanical shock that occurs during shipments. The packaging systems evaluated were boxes containing expanded polystyrene (EPS) or soft lint-like foam, prepared with and without polymer cooling packs. In laboratory-based studies, accelerometers measured g forces in boxes dropped from varying heights. Transportation studies evaluated the EPS cooler when sent to locations via 2 vendors. The relationship between drop height and maximum force vector was approximately linear for drop heights of 7.5″ through 30″, with lower magnitude forces at 45″ and 60″. Soft foam reduced force by 9.8 g on average compared to EPS (p < 0.009). The presence of polymer packs mitigated forces; frozen packs reduced forces by 28 g versus thawed packs (p < 0.001). Transportation experiments demonstrated most impacts were in the low (10-24 g) and low-medium (25-49 g) range (95% of all impacts). There was no difference between impacts during shipments with the vendors, and there was no correlation between distance traveled and number of impacts. Overall, mechanical shock during shipping is both prevalent and contingent upon the packing materials used.

Functional intraepithelial lymphocyte changes in inflammatory bowel disease and spondyloarthritis have disease specific correlations with intestinal microbiota.

BACKGROUND: Dysbiosis occurs in spondyloarthritis (SpA) and inflammatory bowel disease (IBD), which is subdivided into Crohn's disease (CD) and ulcerative colitis (UC). The immunologic consequences of alterations in microbiota, however, have not been defined. Intraepithelial lymphocytes (IELs) are T cells within the intestinal epithelium that are in close contact with bacteria and are likely to be modulated by changes in microbiota. We examined differences in human gut-associated bacteria and tested correlation with functional changes in IELs in patients with axial SpA (axSpA), CD, or UC, and in controls. METHODS: We conducted a case-control study to evaluate IELs from pinch biopsies of grossly normal colonic tissue from subjects with biopsy-proven CD or UC, axSpA fulfilling Assessment of SpondyloArthritis International Society (ASAS) criteria and from controls during endoscopy. IELs were harvested and characterized by flow cytometry for cell surface markers. Secreted cytokines were measured by ELISA. Microbiome analysis was by 16S rRNA gene sequencing from rectal swabs. Statistical analyses were performed with the Kruskal-Wallis and Spearman's rank tests. RESULTS: The total number of IELs was significantly decreased in subjects with axSpA compared to those with IBD and controls, likely due to a decrease in TCRß+ IELs. We found strong, significant negative correlation between peripheral lymphocyte count and IEL number. IELs secreted significantly increased IL-1ß in patients with UC, significantly increased IL-17A and IFN-γ in patients with CD, and significantly increased TNF-α in patients with CD and axSpA as compared to other cohorts. For each disease subtype, IELs and IEL-produced cytokines were positively and negatively correlated with the relative abundance of multiple bacterial taxa. CONCLUSIONS: Our data indicate differences in IEL function among subjects with axSpA, CD, and UC compared to healthy controls. We propose that the observed correlation between altered microbiota and IEL function in these populations are relevant to the pathogenesis of axSpA and IBD, and discuss possible mechanisms. TRIAL REGISTRATION: ClinicalTrials.gov, NCT02389075 . Registered on 17 March 2015.