Emerging evidence indicates an association between gut microbiome and arthritis diseases including gout. However, how and which gut bacteria affect host urate degradation and inflammation in gout remains unclear. Here we performed a metagenome analysis on 307 fecal samples from 102 gout patients and 86 healthy controls. Gout metagenomes significantly differed from those of healthy controls. The relative abundances of Prevotella, Fusobacterium, and Bacteroides were increased in gout, whereas those of Enterobacteriaceae and butyrate-producing species were decreased. Functionally, gout patients had greater abundances for genes in fructose, mannose metabolism and lipid A biosynthesis, and lower for genes in urate degradation and short chain fatty acid production. A three-pronged association between metagenomic species, functions and clinical parameters revealed that decreased abundances of species in Enterobacteriaceae were associated with reduced amino acid metabolism and environmental sensing, which together contribute to increased serum uric acid and C-reactive protein levels in gout. A random forest classifier based on three gut microbial genes showed high predictivity for gout in both discovery and validation cohorts (0.91 and 0.80 accuracy), with high specificity in the context of other chronic disorders. Longitudinal analysis showed that uric-acid-lowering and anti-inflammatory drugs partially restored gut microbiota after 24-week treatment. Comparative analysis with obesity, type 2 diabetes, ankylosing spondylitis and rheumatoid arthritis indicated that gout metagenomes were more similar to those of autoimmune than metabolic diseases. Our results suggest that gut dysbiosis was associated with dysregulated host urate degradation and systemic inflammation and may be used as non-invasive diagnostic markers for gout.

18β-Glycyrrhetinic acid (18β-GA), an active component from Glycyrrhiza glabra L. root (licorice), has been demonstrated to be able to protect against inflammatory response and reduce methotrexate (MTX)-derived toxicity. This study was therefore designed to test the therapeutic possibility of 18β-GA on rheumatoid arthritis (RA) and to explore the underlying mechanism. LPS or TNF-α-induced inflammatory cell models and collagen-induced arthritis (CIA) animal models were applied in this study. Real-time quantitative PCR (RT-qPCR) was used to measure the mRNA levels of various cytokines and FOXO family members. The protein levels of molecules in the MAPK/NF-κB signaling pathway were analyzed using western blot. The cell proliferation assay and colony-forming assay were used to test the influence of 18β-GA on cell viability. The cell apoptosis assay and cell cycle assay were performed to detect the effect of 18β-GA on cell proliferative capacity by using flow cytometry. Hematoxylin and eosin (H&E) staining was performed to evaluate pathological changes after drug administration. The enzyme-linked immunosorbent assay (ELISA) was carried out for the detection of cytokines in serum. In vitro, we found that 18β-GA decreased the mRNA levels of IL-1β, IL-6, and COX-2 by inhibiting the MAPK/NF-κB signaling pathway in MH7A and RAW264.7 cell lines. Moreover, 18β-GA was able to suppress cell viability, trigger cell apoptosis, and G1 phase cell cycle arrest in our in vitro studies. 18β-GA dramatically enhanced the mRNA level of FOXO3 in both TNF-α- and LPS-induced inflammation models in vitro. Interestingly, after analyzing GEO datasets, we found that the FOXO3 gene was significantly decreased in the RA synovial tissue as compared to healthy donors in multiple microarray studies. In vivo, 18β-GA exhibited a promising therapeutic effect in a collagen-induced arthritis mouse model by alleviating joint pathological changes and declining serum levels of TNF-α, IL-1β, and IL-6. Finally, we observed that 18β-GA administration could mitigate liver damage caused by collagen or MTX. Collectively, the current study demonstrates for the first time that 18β-GA can inhibit inflammation and proliferation of synovial cells, and the underlying mechanism may be associated with its inhibition of MAPK/NF-κB signaling and promotion of FOXO3 signaling. Therefore, 18β-GA is expected to be a new drug candidate for RA therapy.

Objective: To conduct a meta-analysis of the effectiveness and safety of Tripterygium wilfordii Hook. F (TwHF) extracts for the treatment of rheumatoid arthritis (RA). Methods: A systematic literature search was conducted in PubMed, EMBASE, Cochrane, Medline, CNKI, SinoMed and WanFang Library till 12 July 2017. All included studies were analyzed with the use of the Review Manager 5.2 software according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) Statement protocol. Results: Fourteen randomized controlled trials (RCTs) were identified. TwHF extracts provided a statistically significant improvement in grip strength (GS), swelling joint count (SJC) and morning stiffness (MS) compared with placebo (P < 0.001). The meta-analysis showed significant differences between TwHF extract-treated group and the DMARDs group in GS, MS, C-reactive protein (CRP), and tender joint count (TJC) (P < 0.05), aside from ESR and SJC (P > 0.05). The pooled results also displayed significant differences between the combination of TwHF extracts with DMARDs and the DMARDs alone group in ESR, CRP, SJC, and TJC (P ≤ 0.05). For the safety analysis, two trials favored TwHF extract-treatment and one trial favored non-TWHF extract-treatment in AEs (P < 0.05). Eleven trials showed no statistically significant differences between TwHF extract-treated group and the DMARDs group (P > 0.05). Conclusions: The findings of this systematic review with meta-analysis indicate that TwHF extracts provides statistically significant and clinically important improvement in RA symptoms and has an acceptable safety profile.

Introduction. Ankylosing spondylitis (AS) is a systemic progressive disease with an unknown etiology that may be related to the gut microbiome. Therefore, a more thorough understanding of its pathogenesis is necessary for directing future therapy. Aim. We aimed to determine the differences in intestinal microbial composition between healthy individuals and patients with AS who received and who did not receive treatment interventions. In parallel, the pathology of AS in each patient was analysed to better understand the link between AS treatment and the intestinal microbiota of the patients. Methodology. Sixty-six faecal DNA samples, including 37 from healthy controls (HCs), 11 from patients with untreated AS (NM), 7 from patients treated with nonsteroidal anti-inflammatory drugs (e.g. celecoxib; WM) and 11 from patients treated with Chinese herbal medicine (CHM), such as the Bushen–Qiangdu–Zhilv decoction, were collected and used in the drug effect analysis. All samples were sequenced using Illumina HiSeq 4000 and the microbial composition was determined. Results. Four species were enriched in the patients with AS: Flavonifractor plautii , Oscillibacter , Parabacteroides distasonis and Bacteroides nordii (HC vs. NM, P<0.05); only F. plautii was found to be significantly changed in the NM-HC comparison. No additional species were found in the HC vs. CHM analysis, which indicated a beneficial effect of CHM in removing the other three strains. F. plautii was found to be significantly increased in the comparison between the HC and WM groups, along with four other species ( Clostridium bolteae , Clostridiales bacterium 1_7_47FAA, C. asparagiforme and C. hathewayi ). The patients with AS harboured more bacterial species associated with carbohydrate metabolism and glycan biosynthesis in their faeces. They also had bacterial profiles less able to biodegrade xenobiotics or synthesize and transport vitamins. Conclusion. The gut microbiota of the patients with AS varied from that of the HCs, and the treatment had an impact on this divergence. Our data provide insight that could guide improvements in AS treatment.

Several studies have investigated the causative role of the microbiome in the development of rheumatoid arthritis (RA), but changes in the gut microbiome in RA patients during drug treatment have been less well studied. Here, we tracked the longitudinal changes in gut bacteria in 22 RA patients who were randomized into two groups and treated with Huayu-Qiangshen-Tongbi formula (HQT) plus methotrexate (MTX) or leflunomide (LEF) plus MTX. There were differences in the gut microbiome between untreated (at baseline) RA patients and healthy controls, with 37 species being more abundant in the RA patients and 21 species (including Clostridium celatum) being less abundant. Regarding the functional analysis, vitamin K2 biosynthesis was associated with RA-enriched bacteria. Additionally, in RA patients, alterations in gut microbial species appeared to be associated with RA-related clinical indicators through changing various gut microbiome functional pathways. The clinical efficacy of the two treatments was further observed to be similar, but the response trends of RA-related clinical indices in the two treatment groups differed. For example, HQT treatment affected the erythrocyte sedimentation rate (ESR), while LEF treatment affected the C-reactive protein (CRP) level. Further, 11 species and 9 metabolic pathways significantly changed over time in the HQT group (including C. celatum, which increased), while only 4 species and 2 metabolic pathways significantly changed over time in the LEF group. In summary, we studied the alterations in the gut microbiome of RA patients being treated with HQT or LEF. The results provide useful information on the role of the gut microbiota in the pathogenesis of RA, and they also provide potentially effective directions for developing new RA treatments.

Angiogenesis, integral to the pathogenesis of rheumatoid arthritis (RA), contributes to the advancement of synovial hyperplasia, pannus formation, and bone destruction. The precise effect of the Huayu Tongbi formula (HT), a proven traditional Chinese medicine for RA treatment, on angiogenesis remains uncertain. To investigate the effects of HT on RA angiogenesis and the potential underlying molecular mechanisms. The target spectrum and pharmacological effects of HT were screened using network pharmacology. In vitro, RA-FLS were stimulated with CoCl₂ to simulate hypoxic conditions. Human umbilical vein endothelial cells (HUVECs) were cultured with conditioned medium (CM) from RA-FLS supplemented with HT or the HIF1A inhibitor LW-6 to investigate the impact of synovial cell secretions on angiogenesis, encompassing proliferation, migration, adhesion, and lumen formation. Western blot was employed to assess protein levels of hypoxia-inducible factor 1 subunit alpha (HIF1A), vascular endothelial growth factor receptor 2 (VEGFR2), and phosphorylated VEGFR2 (p-VEGFR2). Enzyme-linked immunosorbent assay (ELISA) was utilized to quantify VEGFA secretion, while quantitative real-time PCR (qRT‒PCR) measured mRNA expression of VEGFA, Angiopoietin 1 (ANGPT1), and ANGPT2. In vivo, a collagen-induced arthritis (CIA) model was established. Pathological changes and vessel counts were observed via hematoxylin-eosin (HE) staining, bone structure was evaluated using X-ray, mature and immature vessels were classified via immunofluorescence, and the mechanism was further verified using immunohistochemistry and ELISA. Liquid chromatography‒mass spectrometry (LC‒MS) was employed to identify the active components of HT drug-containing serum, and the potential metabolites were identified by bioinformatics analysis. Network pharmacology analysis indicated potential targets of HT in angiogenesis, correlating with HIF1A and VEGF pathways. In vitro, HT reversed proliferation, migration, and adhesion of the cell lines and suppressed luminal formation by HUVECs. HT (10 % and 15 %) effectively reduced HIF1A and VEGFA expression, attenuated VEGFR2 levels and its phosphorylation, and downregulated VEGFA, ANGPT1, and ANGPT2 mRNA levels. In vivo, HT mitigated inflammation and bone destruction, reduced immature (CD31+/α-SMA-) and mature (CD31+/α-SMA+) vessel counts in the synovium, and inhibited the HIF1A-VEGFA-ANGPT axis. Finally, 19 active components from HT drug-containing serum were successfully identified, and we also unexpectedly discovered that HT might affect metabolic pathways such as proline and tyrosine metabolism, which have been reported to be involved in angiogenesis. HT has a promising effect on alleviating RA angiogenesis, at least in part through HIF1A-VEGFA-ANGPT axis inhibition, which reduces the cross-talk between RA-FLS and HUVECs. Our results suggest that HT is a drug candidate for the treatment of RA angiogenesis.