Ankylosing spondylitis is linked to Klebsiella--the evidence

The Role of Diet in Modulating Inflammation and Oxidative Stress in Rheumatoid Arthritis, Ankylosing Spondylitis, and Psoriatic Arthritis

Rheumatic diseases such as rheumatoid arthritis (RA), ankylosing spondylitis (AS), and psoriatic arthritis (PsA) are chronic autoimmune disorders characterized by persistent inflammation and oxidative stress, leading to joint damage and reduced quality of life. In recent years, increasing attention has been given to diet as a modifiable environmental factor that can complement pharmacological therapy. This review summarizes current evidence on how key dietary components-such as omega-3 fatty acids, fiber, polyphenols, and antioxidant vitamins-affect inflammatory pathways and oxidative balance. Special emphasis is placed on the Mediterranean diet, low-starch diets, and hypocaloric regimens, which have shown potential in improving disease activity. The gut microbiota emerges as a critical mediator between diet and immune function, with dietary interventions capable of restoring eubiosis and strengthening the intestinal barrier. Additionally, this paper discusses challenges in the clinical implementation of diet therapy, the need for personalized nutritional strategies, and the importance of integrating diet into holistic patient care. Collectively, findings suggest that dietary interventions may reduce disease activity, mitigate systemic inflammation, and enhance patients' overall well-being.

Converging pathways of ankylosing spondylitis and rheumatic fever: A unique case

Ankylosing spondylitis is a chronic inflammatory disease that belongs to the group of seronegative spondyloarthropathies. Rheumatic fever is an abnormal immune response to group A Streptococcus infections. Severe or recurrent episodes of rheumatic fever can lead to significant morbidity and mortality, often resulting in the development of rheumatic heart disease. We present a unique case of a 50-year-old patient who suffered from rheumatic fever during childhood, which was complicated by mitral stenosis. He underwent surgical mitral valve replacement at the age of 35. At 47, he was diagnosed with ankylosing spondylitis following a 3-year history of worsening symptoms. This is the first case in the medical literature describing a patient with mitral stenosis postrheumatic fever coexisting with ankylosing spondylitis. A microbial infection triggering the autoimmune system in genetically susceptible individuals may be the underlying mechanism. However, further research is needed to fully understand the converging pathways of these 2 diseases.

A review of long non-coding RNAs in ankylosing spondylitis: pathogenesis, clinical assessment, and therapeutic targets

Ankylosing spondylitis (AS) is a chronic immune-mediated type of inflammatory arthritis characterized by inflammation, bone erosion, and stiffness of the spine and sacroiliac joints. Despite great efforts put into the investigation of the disease, the pathogenesis of AS remains unclear, posing challenges in identifying ideal targets for diagnosis and treatment. To enhance our understanding of AS, an increasing number of studies have been conducted. Some of these studies reveal that long non-coding RNAs (lncRNAs) play crucial roles in the etiology of AS. Some certain lncRNAs influence the development of AS by regulating inflammatory responses, autophagy, apoptosis, and adipogenesis, as well as the proliferation and differentiation of cells. Additionally, some lncRNAs demonstrate potential as biomarkers, aiding in monitoring disease progression and predicting prognosis. In this review, we summarize recent studies concerning lncRNAs in AS to elucidate the underlying mechanisms in which lncRNAs are involved and their potential values as biomarkers for disease assessment and druggable targets for therapy.

Regulatory mechanisms of miR-212-3p on the secretion of inflammatory factors in monocyte-macrophages and the directed differentiation into osteoclasts in ankylosing spondylitis

To explore the mechanisms of action of micro ribonucleic acid (miR)-212-3p in the secretion of inflammatory factors in monocyte-macrophages and the directed differentiation into osteoclasts (OCs) in ankylosing spondylitis (AS), proteoglycan was used to establish an AS mouse model. The mouse monocyte-macrophages were cultured in vitro, transfected with miR-212-3p mimic, and added with phosphorylated-extracellular signal-regulated kinase (p-ERK)1/2 agonist Ro67-7476 in vitro. After the cells were transfected with the miR-212-3p mimic in each group, the expressions of p-ERK1/2, matrix metalloproteinase-1 (MMP-1), MMP-3, interleukin-1β (IL-1β), and tumor necrosis factor-α (TNF-α) significantly declined, whereas those of tartrate-resistant acid phosphatase (TRAP), calcitonin, and p-nuclear factor of activated T cell 1 (NFATC1) significantly rose. After Ro67-7476 was added, the protein expressions of p-ERK1/2, MMP-1, MMP-3, IL-1β, and TNF-α were significantly increased in each group, but they displayed decreasing trends in cells transfected with the miR-212-3p mimic. In contrast, the protein expressions of TRAP, calcitonin, and p-NFATC1 declined, but they showed increasing trends in cells transfected with the miR-212-3p mimic. miR-212-3p can, through inhibiting the phosphorylation of p-ERK1/2, prevent the aggregation of macrophages and the secretion of inflammatory factors. It also up-regulates the expression of OC marker proteins to facilitate the differentiation and maturation of OCs, ultimately relieving AS-induced inflammation and new bone growth-induced joint neoplasm.

Down-regulation of long noncoding RNA HULC inhibits the inflammatory response in ankylosing spondylitis by reducing miR-556-5p-mediated YAP1 expression

OBJECTIVE

Ankylosing spondylitis (AS) is a progressive systemic disease characterized by a chronic inflammatory response in the sacroiliac joints and spine. Long noncoding RNAs suggest significant actions in the progression of AS. Therefore, a specific lncRNA, highly upregulated in liver cancer (HULC), was studied here regarding its functions and related mechanisms in AS.

METHODS

Measurements of miR-556-5p, HULC, and YAP1 expression were performed on AS cartilage tissues and chondrocytes. The interaction between miR-556-5p and HULC or YAP1 was verified. CCK-8, flow cytometry and enzyme-linked immunosorbent assay were used to evaluate the effects of HULC, miR-556-5p, and YAP1 on the proliferation, apoptosis, and inflammatory response of AS chondrocytes. Furthermore, the action of HULC/miR-556-5p/YAP1 was experimentally observed in AS mice.

RESULTS

HULC and YAP1 levels were augmented, while miR-556-5p levels were suppressed in AS cartilage tissues and chondrocytes. Downregulating HULC or upregulating miR-556-5p stimulated chondrocyte proliferation and inhibited apoptosis and inflammation in AS. miR-556-5p was a downstream factor of HULC, and YAP1 was a potential target of miR-556-5p. The improvement effect of downregulated HULC on AS chondrocytes was saved when YAP1 expression was forced. In addition, silence of HULC improved the pathological injury of spinal cartilage in AS mice by enhancing miR-556-5p-related regulation of YAP1.

CONCLUSION

HULC inhibition relieves the inflammatory response in AS by reducing miR-556-5p-mediated YAP1 expression.

Comprehensive profiling of extracellular vesicles in uveitis and scleritis enables biomarker discovery and mechanism exploration

BACKGROUND

Uveitis and posterior scleritis are sight-threatening diseases with undefined pathogenesis and accurate diagnosis remains challenging.

METHODS

Two plasma-derived extracellular vesicle (EV) subpopulations, small and large EVs, obtained from patients with ankylosing spondylitis-related uveitis, Behcet's disease uveitis, Vogt-Koyanagi-Harada syndrome, and posterior scleritis were subjected to proteomics analysis alongside plasma using SWATH-MS. A comprehensive bioinformatics analysis was performed on the proteomic profiles of sEVs, lEVs, and plasma. Candidate biomarkers were validated in a new cohort using ELISA. Pearson correlation analysis was performed to analyze the relationship between clinical parameters and proteomic data. Connectivity map database was used to predict therapeutic agents.

RESULTS

In total, 3,668 proteins were identified and over 3000 proteins were quantified from 278 samples. When comparing diseased group to healthy control, the proteomic profiles of the two EV subgroups were more correlated with disease than plasma. Comprehensive bioinformatics analysis highlighted potential pathogenic mechanisms for these diseases. Potential biomarker panels for four diseases were identified and validated. We found a negative correlation between plasma endothelin-converting enzyme 1 level and mean retinal thickness. Potential therapeutic drugs were proposed, and their targets were identified.

CONCLUSIONS

This study provides a proteomic landscape of plasma and EVs involved in ankylosing spondylitis-related uveitis, Behcet's disease uveitis, Vogt-Koyanagi-Harada syndrome, and posterior scleritis, offers insights into disease pathogenesis, identifies valuable biomarker candidates, and proposes promising therapeutic agents.

RNA sequencing and bioinformatics analysis of differentially expressed genes in the peripheral serum of ankylosing spondylitis patients

BACKGROUND

Ankylosing spondylitis (AS) is a chronic progressive autoimmune disease characterized by spinal and sacroiliac arthritis, but its pathogenesis and genetic basis are largely unclear.

METHODS

We randomly selected three serum samples each from an AS and a normal control (NC) group for high-throughput sequencing followed by using edgeR to find differentially expressed genes (DEGs). Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes, Reactome pathway analyses, and Gene Set Enrichment Analysis were used to comprehensively analyze the possible functions and pathways involved with these DEGs. Protein-protein interaction (PPI) networks were constructed using the STRING database and Cytoscape. The modules and hub genes of these DEGs were identified using MCODE and CytoHubba plugins. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was used to validate the expression levels of candidate genes in serum samples from AS patients and healthy controls.

RESULTS

We successfully identified 100 significant DEGs in serum. When we compared them with the NC group, 49 of these genes were upregulated in AS patients and 51 were downregulated. GO function and pathway enrichment analysis indicated that these DEGs were mainly enriched in several signaling pathways associated with endoplasmic reticulum stress, including protein processing in the endoplasmic reticulum, unfolded protein response, and ubiquitin-mediated proteolysis. We also constructed a PPI network and identified the highly connected top 10 hub genes. The expression levels of the candidate hub genes PPARG, MDM2, DNA2, STUB1, UBTF, and SLC25A37 were then validated by RT-qPCR analysis. Finally, receiver operating characteristic curve analysis suggested that PPARG and MDM2 may be the potential biomarkers of AS.

CONCLUSIONS

These findings may help to further elucidate the pathogenesis of AS and provide valuable potential gene biomarkers or targets for the diagnosis and treatment of AS.

Interactions between NSAIDs, opioids and the gut microbiota - Future perspectives in the management of inflammation and pain

The composition of intestinal microbiota is influenced by a number of factors, including medications, which may have a substantial impact on host physiology. Nonsteroidal anti-inflammatory drugs (NSAIDs) and opioid analgesics are among those widely used medications that have been shown to alter microbiota composition in both animals and humans. Although much effort has been devoted to identify microbiota signatures associated with these medications, much less is known about the underlying mechanisms. Mucosal inflammation, changes in intestinal motility, luminal pH and bile acid metabolism, or direct drug-induced inhibitory effect on bacterial growth are all potential contributors to NSAID- and opioid-induced dysbiosis, however, only a few studies have addressed directly these issues. In addition, there is a notable overlap between the microbiota signatures of these drugs and certain diseases in which they are used, such as spondyloarthritis (SpA), rheumatoid arthritis (RA) and neuropathic pain associated with type 2 diabetes (T2D). The aims of the present review are threefold. First, we aim to provide a comprehensive up-to-date summary on the bacterial alterations caused by NSAIDs and opioids. Second, we critically review the available data on the possible underlying mechanisms of dysbiosis. Third, we review the current knowledge on gut dysbiosis associated with SpA, RA and neuropathic pain in T2D, and highlight the similarities between them and those caused by NSAIDs and opioids. We posit that drug-induced dysbiosis may contribute to the persistence of these diseases, and may potentially limit the therapeutic effect of these medications by long-term use. In this context, we will review the available literature data on the effect of probiotic supplementation and fecal microbiota transplantation on the therapeutic efficacy of NSAIDs and opioids in these diseases.

Proteus mirabilis and Klebsiella pneumoniae as pathogens capable of causing co-infections and exhibiting similarities in their virulence factors

The genera Klebsiella and Proteus were independently described in 1885. These Gram-negative rods colonize the human intestinal tract regarded as the main reservoir of these opportunistic pathogens. In favorable conditions they cause infections, often hospital-acquired ones. The activity of K. pneumoniae and P. mirabilis, the leading pathogens within each genus, results in infections of the urinary (UTIs) and respiratory tracts, wounds, bacteremia, affecting mainly immunocompromised patients. P. mirabilis and K. pneumoniae cause polymicrobial UTIs, which are often persistent due to the catheter biofilm formation or increasing resistance of the bacteria to antibiotics. In this situation a need arises to find the antigens with features common to both species. Among many virulence factors produced by both pathogens urease shows some structural similarities but the biggest similarities have been observed in lipids A and the core regions of lipopolysaccharides (LPSs). Both species produce capsular polysaccharides (CPSs) but only in K. pneumoniae these antigens play a crucial role in the serological classification scheme, which in Proteus spp. is based on the structural and serological diversity of LPS O-polysaccharides (OPSs). Structural and serological similarities observed for Klebsiella spp. and Proteus spp. polysaccharides are important in the search for the cross-reacting vaccine antigens.

Association of anti-TNF-α treatment with gut microbiota of patients with ankylosing spondylitis

OBJECTIVE

Gut dysbiosis contributes to multiple autoimmune diseases, including ankylosing spondylitis, which is commonly treated with tumor necrosis factor (TNF)-α inhibitors (TNFis). Because host TNF-α levels are considered to interact with gut microbiota, we aimed to systematically investigate the microbiota profile of ankylosing spondylitis patients with anti-TNF-α-based treatment and identify potential key bacteria.

METHODS

Fecal samples were collected from 11 healthy controls and 24 ankylosing spondylitis patients before/after anti-TNF-α treatment, the microbiota profiles of which were evaluated by 16S ribosomal DNA amplicon sequencing and subsequent bioinformatic analysis.

RESULTS

Significantly different microbial compositions were observed in samples from ankylosing spondylitis patients compared with healthy controls, characterized by a lower abundance of short-chain fatty acid (SCFA)-producing bacteria. All patients exhibited a positive response after anti-TNF-α treatment, accompanied by a trend of restoration in the microbiota compositions and functional profile of ankylosing spondylitis patients to healthy controls. In particular, the abundance of SCFA-producing bacteria (e.g. Megamonsa and Lachnoclostridium ) was not only significantly lower in ankylosing spondylitis patients than in healthy controls and restored after anti-TNF-α treatment but also negatively correlated with disease severity (e.g. cor  = -0.52, P  = 8 × 10 -5 for Megamonsa ). In contrast, Bacilli and Haemophilus may contribute to ankylosing spondylitis onset and severity.

CONCLUSIONS

Microbiota dysbiosis in ankylosing spondylitis patients can be restored after anti-TNF-α treatment, possibly by impacting SCFA-producing bacteria.

Microbiota-assisted therapy for systemic inflammatory arthritis: advances and mechanistic insights

Research on the influence of gut microbiota on systemic inflammatory arthritis has exploded in the past decade. Gut microbiota changes may be a crucial regulatory component in systemic inflammatory arthritis. As a result of advancements in the field, microbiota-assisted therapy has evolved, but this discipline is still in its infancy. Consequently, we review the limitations of current systemic inflammatory arthritis treatment, analyze the connection between the microbiota and arthritis, and summarize the research progress of microbiota regulating systemic inflammatory arthritis and the further development aspects of microbiota-assisted therapy. Finally, the partial mechanisms of microbiota-assisted therapy of systemic inflammatory arthritis are being discussed. In general, this review summarizes the current progress, challenges, and prospects of microbiota-assisted therapy for systemic inflammatory arthritis and points out the direction for the development of microbiota-assisted therapy in the future.

Association between Klebsiella pneumoniae and ankylosing spondylitis: A systematic review and meta-analysis

AIM

The aim of this study is to evaluate the association between Klebsiella pneumoniae infection and ankylosing spondylitis (AS).

METHOD

Five electronic databases, PubMed, Embase, Medline, Web of Science, and Scopes, were searched until September 29, 2021. Cohort and case-control studies that assessed the association between K. pneumoniae infection and AS were included. Pooled odds ratio (OR) was selected to show the effect size. Subgroup analysis (active or inactive AS) and 2 forms of sensitivity analysis were conducted. All statistical analyses were conducted by using STATA 12.0.

RESULTS

There were 25 case-control studies finally included, including 8 studies concerning presence of K. pneumoniae in feces, and 17 studies concerning serum antibody (immunoglobulin [Ig]G, IgM, IgA) against K. pneumoniae. The results suggested that when compared with healthy people, presence of K. pneumoniae in feces was associated with AS (OR: 5.65; 95% CI: 1.68-19.00). Similarly, when compared with healthy people, higher positive rates of IgA (OR: 6.28; 95% CI: 3.32-11.91) and IgG (OR: 5.22; 95% CI: 1.36-19.99) were observed. Subgroup analyses suggested that association between K. pneumoniae and AS appears stronger in active AS.

CONCLUSION

When compared with healthy people, a significantly higher positive rate of K. pneumoniae in feces, serum IgA and IgG were observed in patients with AS, suggesting that K. pneumoniae probably plays a crucial role in the occurrence of AS. The findings in this study need further prospective investigations for confirmation.

Comparison of the antibacterial activity of Australian Terminalia spp. extracts against Klebsiella pneumoniae: a potential treatment for ankylosing spondylitis

Traditional medicines prepared using Terminalia species have been used globally to treat inflammation and pathogenic infections. Recent studies have demonstrated that multiple Asian and African Terminalia spp. inhibit bacterial triggers of some autoimmune inflammatory diseases, including ankylosing spondylitis. Despite this, the effects of Australian Terminalia spp. on a bacterial trigger of ankylosing spondylitis (K. pneumoniae) remain unexplored. Fifty-five extracts from five Australian Terminalia spp. were investigated for K. pneumoniae growth inhibitory activity. Methanolic, aqueous and ethyl acetate extracts of most species and plant parts inhibited K. pneumoniae growth, with varying potencies. Methanolic leaf extracts were generally the most potent bacterial growth inhibitors, with minimum inhibitory concentration (MIC) values of 66 μg/mL (T. ferdinandiana), 128 μg/mL (T. carpenteriae) and 83 μg/mL (T. petiolares). However, the aqueous leaf extract was the most potent T. grandiflora extract (MIC = 87 μg/mL). All T. catappa extracts displayed low growth inhibitory activity. The Terminalia spp. methanolic leaf extracts were examined by liquid chromatography-mass spectrometry (LC-MS) and gas chromatography-mass spectrometry (GC-MS). All contained a relative abundance of simple gallotannins (particularly gallic and chebulic acids), the flavonoid luteolin, as well as the monoterpenoids cineole and terpineol. Notably, all Terminalia spp. were non-toxic or of low toxicity in ALA and HDF toxicity assays, highlighting their potential for preventing the onset of ankylosing spondylitis and treating its symptoms once the disease is established, although this needs to be verified in in vivo systems.

Similarities and Differences Between Juvenile and Adult Spondyloarthropathies

Spondyloarthritis (SpA) encompasses a broad spectrum of conditions occurring from childhood to middle age. Key features of SpA include axial and peripheral arthritis, enthesitis, extra-articular manifestations, and a strong association with HLA-B27. These features are common across the ages but there are important differences between juvenile and adult onset disease. Juvenile SpA predominantly affects the peripheral joints and the incidence of axial arthritis increases with age. Enthesitis is important in early disease. This review article highlights the similarities and differences between juvenile and adult SpA including classification, pathogenesis, clinical features, imaging, therapeutic strategies, and disease outcomes. In addition, the impact of the biological transition from childhood to adulthood is explored including the importance of musculoskeletal and immunological maturation. We discuss how the changes associated with adolescence may be important in explaining age-related differences in the clinical phenotype between juvenile and adult SpA and their implications for the treatment of juvenile SpA.

Identification of lncRNAs associated with the pathogenesis of ankylosing spondylitis

Background

Ankylosing spondylitis (AS) is a chronic autoimmune disease affecting the sacroiliac joint. To date, few studies have examined the association between long non-coding RNAs (lncRNAs) and AS pathogenesis. As such, we herein sought to characterize patterns of AS-related lncRNA expression and to evaluate the potential role played by these lncRNAs in this complex autoimmune context.

Methods

We conducted a RNA-seq analysis of peripheral blood mononuclear cell (PBMC) samples isolated from five AS patients and corresponding controls. These data were then leveraged to characterize AS-related lncRNA expression patterns. We further conducted GO and KEGG enrichment analyses of the parental genes encoding these lncRNAs, and we confirmed the validity of our RNA-seq data by assessing the expression of six lncRNAs via qRT-PCR in 15 AS and control patient samples. Pearson correlation analyses were additionally employed to examine the associations between the expression levels of these six lncRNAs and patient clinical index values.

Results

We detected 56,575 total lncRNAs in AS and control patient samples during our initial RNA-seq analysis, of which 200 and 70 were found to be up- and down-regulated (FC > 2 or < 0.05; P < 0.05), respectively, in AS samples relative to controls. In qRT-PCR validation assays, we confirmed the significant upregulation of NONHSAT118801.2, ENST00000444046, and NONHSAT183847.1 and the significant downregulation of NONHSAT205110.1, NONHSAT105444.2, and NONHSAT051856.2 in AS patient samples. We further found the expression of NONHSAT118801.2 and NONHSAT183847.1 to be positively correlated with disease severity.

Conclusion

Overall, our findings highlight several lncRNAs that are specifically expressed in PBMCs of AS patients, indicating that they may play key functions in the pathogenesis of this autoimmune disease. Specifically, we determined that NONHSAT118801.2 and NONHSAT183847.1 may influence the occurrence and development of AS.

Microbes, helminths, and rheumatic diseases

There has been a progressive interest on modifications of the human defense system following insults occurring in the interface between our body and the external environment, as they may provoke or worsen disease states. Studies suggest that billions of germs, which compose the gut microbiota influence one's innate and adaptive immune responses at the intestinal level, but these microorganisms may also impact rheumatic diseases. The microbiota of the skin, respiratory, and urinary tracts may also be relevant in rheumatology. Evidence indicates that changes in the gut microbiome alter the pathogenesis of immune-mediated diseases such as rheumatoid arthritis and ankylosing spondylitis but also of other disorders like atherosclerosis and osteoarthritis. Therapeutic strategies to modify the microbiota, including probiotics and fecal microbiota transplantation, have been received with skepticism, which, in turn, has drawn attention back to previously developed interventions such as antibiotics. Helminths adapted to humans over the evolution process, but their role in disease modulation, particularly immune-mediated diseases, remains to be understood. The present review focuses on data concerning modifications of the immune system induced by interactions with microbes and pluricellular organisms, namely helminths, and their impact on rheumatic diseases. Practical aspects, including specific microbiota-targeted therapies, are also discussed.

Advances in nanomedicine for the treatment of ankylosing spondylitis

Ankylosing spondylitis (AS) is a complex disease characterized by inflammation and ankylosis primarily at the cartilage-bone interface. The disease is more common in young males and risk factors include both genetic and environmental. While the pathogenesis of AS is not completely understood, it is thought to be an immune-mediated disease involving inflammatory cellular infiltrates, and human leukocyte antigen-B27. Currently, there is no specific diagnostic technique available for this disease; therefore conventional diagnostic approaches such as clinical symptoms, laboratory tests and imaging techniques are used. There are various review papers that have been published on conventional treatment approaches, and in this review work, we focus on the more promising nanomedicine-based treatment modalities to move this field forward.

Preparation and Characterization of Agar Based Magnetic Nanocomposite for Potential Biomedical Applications

PURPOSE

The purpose of the present study was to make a biocompatible agar based composite material via incorporation of appropriate additives within the agar matrix for potential applications in drug delivery and biomedical fields.

METHODOLOGY

Agar based composites were prepared by the incorporation of magnetic iron oxide nano particles, graphite and sodium aluminum as additives in different proportions within the agar matrix by a simple thermophysico- mechanical method. The as prepared agar based composites were then characterized by different techniques i.e. FTIR, SEM, TGA, XRD and EDX analyses. The FTIR peaks confirmed the presence of each component in the agar composite. SEM images showed the uniform distribution of each component in the agar composite. TGA study showed the thermal stability range of different composite sheets. XRD pattern revealed the crystallinity and EDX analysis confirmed the elemental composition of the prepared composites. The prepared agar based composites were evaluated for antimicrobial activities against three pathogenic bacterial strains Escherichia coli, Staphylococcus aureus and Klebsiella pneumonia and the result indicated efficient antimicrobial activities for all composites.

CONCLUSION

From the overall study, it was concluded that due to the non-toxic nature, thermal stability and excellent antibacterial properties, the prepared agar based composites can receive potential biomedical applications.

Ankylosing spondylitis: etiology, pathogenesis, and treatments

Ankylosing spondylitis (AS), a common type of spondyloarthropathy, is a chronic inflammatory autoimmune disease that mainly affects spine joints, causing severe, chronic pain; additionally, in more advanced cases, it can cause spine fusion. Significant progress in its pathophysiology and treatment has been achieved in the last decade. Immune cells and innate cytokines have been suggested to be crucial in the pathogenesis of AS, especially human leukocyte antigen (HLA)‑B27 and the interleukin‑23/17 axis. However, the pathogenesis of AS remains unclear. The current study reviewed the etiology and pathogenesis of AS, including genome-wide association studies and cytokine pathways. This study also summarized the current pharmaceutical and surgical treatment with a discussion of future potential therapies.

Spondyloarthritis: new insights into clinical aspects, translational immunology and therapeutics

PURPOSE OF REVIEW

The spondyloarthopathies (SpA), which encompass related diseases that were originally viewed as autoimmune, are now known to have a strong innate immune or autoinflammatory initiation phase characterized by disease localization to tissue-specific sites based on the nuances and microanatomy and immunology of those sites. This review covers recent translational advances in the field of SpA.

RECENT FINDINGS

Imaging studies in SpA continue to add support for the pivotal role of enthesitis in disease initiation and expression. Although in its infancy, there is growing evidence for microbiotal intestinal dysbiosis in ankylosing spondylitis and psoriatic arthritis. The role of cytokines beyond tumour necrosis factor (TNF) continues to grow with support for the interleukin (IL)-23/17 axis being key to disease and emergent evidence for the importance of the IL-36 pathway. The treatment of inflammatory bowel disease (IBD) with vedolizumab an α4β7-integrin blocker has been associated with arthritis flares and small molecules with Janus kinase inhibition appear to be as effective as the anti-TNFs. The disparate response of different domains in SpA points towards immunological heterogeneity even within what was considered a homogeneous disease.

SUMMARY

The clinical aspects and translational immunology and therapeutics of SpA continue to evolve and indicate the complexity of diagnosis and treatment of these conditions.

Overexpression of Long Noncoding RNAs (lncRNA) NF-κβ-Interacting Long Noncoding RNA (NKILA) in Ankylosing Spondylitis is Correlated with Transforming Growth Factor β1 (TGF-β1), Active Disease and Predicts Length of Treatment

Background

Long noncoding RNAs (lncRNA) NF-κβ-interacting long noncoding RNA (NKILA) is downregulated in various types of cancers, while its involvement in other diseases is unknown. In the present study we found that plasma lncRNA NKILA was expressed at higher levels in active ankylosing spondylitis patients than in healthy controls.

Material/Methods

According to Youden’s index, active disease patients were divided into high and low lncRNA NKILA groups.

Results

Patients in the high lncRNA NKILA level group had significantly longer length of treatment and higher re-hospitalization rate at 3 years after discharge. Plasma levels of TGF-β1 were also higher in active ankylosing spondylitis patients than in healthy controls. Levels of plasma lncRNA NKILA and TGF-β1 were significantly and positively correlated in ankylosing spondylitis patients but not in healthy controls.

Conclusions

Overexpression of lncRNA NKILA in ankylosing spondylitis is correlated with active disease and predicts length of treatment. LncRNA NKILA may participate in ankylosing spondylitis through the interaction with TGF-β1, which is a key player in this disease.

Usefulness of complex bacteriological and serological analysis in patients with spondyloarthritis

Spondyloarthritis (SpA) is a group of associated chronic systemic inflammatory immune-mediated rheumatic diseases affecting axial and peripheral joints and entheses. The aim of the present study was to identify what parameters are useful to determine in order to better understand the correlation between the disease activity/severity and the microbiological results/immune status against intestinal and/or urogenital pathogens. Microorganisms known to trigger SpA, including Klebsiella spp., Yersinia spp., Salmonella spp., Campylobacter spp. and Chlamydia spp., were analyzed in various specimens (stool, urine, synovial fluid and serum) collected from 27 randomly selected SpA patients and 26 healthy controls using a combined direct and indirect approach relying on conventional culture technique and nucleic acid-based assays together with serological testing by ELISA. Although Escherichia coli derived from phylogroup A prevailed in the gut microflora of the patients and controls, differences were observed regarding the representatives of the other phylogroups with a higher prevalence of E.coli members of phylogenetic group B1 in the stool specimens of patients. Antibodies against the targeted species were detected in SpA patients and controls, and the serological profiles of the former were more diverse and complex. In conclusion, the detection of anti-bacterial antibodies combined with other specific laboratory investigations should be more extensively used to monitor SpA patients in association with their symptoms and in order to determine and administer more effective therapeutics.

The role of HLA-B*27 in spondyloarthritis

The mechanism by which HLA-B*27 predisposes to spondyloarthritis remains unresolved. Arthritogenic peptides have not been defined in humans and are not involved in experimental models of spondyloarthritis. Aberrant properties of HLA-B*27 can activate the IL-23/IL-17 axis in HLA-B*27 transgenic rats and humans. In HLA-B*27-independent rodent models, spondyloarthritis can be driven by IL-23 triggering entheseal-resident CD4^-/CD8^- T cells or CD4⁺ Th17 T cells. These findings point toward noncanonical mechanisms linking HLA-B*27 to the disease and provide a potential explanation for HLA-B*27-negative spondyloarthritis. Gut microbial dysbiosis may be important in the development of spondyloarthritis. HLA-B*27-induced changes in gut microbiota are complex and suggest an ecological model of dysbiosis in rodents. The importance of the IL-23/IL-17 axis in ankylosing spondylitis has been demonstrated by studies showing efficacy of IL-17. Although deciphering the precise role(s) of HLA-B*27 in disease requires further investigation, considerable progress has been made in understanding this complex relationship.

The MicroRNA-326: Autoimmune diseases, diagnostic biomarker, and therapeutic target

MicroRNAs (miRNAs) are uniquely regulated in healthy, inflamed, activated, cancerous, or other cells and tissues of a pathological state. Many studies confirm that immune dysregulation and autoimmune diseases with inflammation are correlated with various miRNA expression changes in targeted tissues and cells in innate or adaptive immunity. In this review, we will explain the history and classification of epigenetic changes. Next, we will describe the role of miRNAs changes, especially mir-326 in autoimmunity, autoinflammatory, and other pathological conditions. A systematic search of MEDLINE, Embase, and Cochrane Library was presented for all related studies from 1899 to 2017 with restrictions in the English language. In recent years, researchers have concentrated on mostly those roles of miRNA that are correlated with the inflammatory and anti-inflammatory process. Latest studies have proposed a fundamental pathogenic role in cancers and autoinflammatory diseases. Studies have described the role of microRNAs in autoimmunity and autoinflammatory diseases, cancers, and so on. The miRNA-326 expression plays a significant role in autoimmune and other types of diseases.

Stress proteins in the pathogenesis of spondyloarthritis

Spondyloarthritis is an autoinflammatory rheumatic disease in which arthritis and osteoproliferation lead the patients who suffer from it to chronic disability. This disease is associated with the expression of class I MHC molecule HLA-B27, which tends to be misfolded in the endoplasmic reticulum and, therefore, expressed in aberrant forms. This phenomena lead to endoplasmic reticulum stress, which in time, evokes a whole response to cellular injury. Under these conditions, the molecules involved in restoring cell homeostasis play a key role. Such is the case of the "heat-shock proteins", which usually regulate protein folding, but also have important immunomodulatory functions, as well as some roles in tissue modeling. In this review, we attempt to summarize the involvement of cell stress and heat-shock proteins in the homeostatic disturbances and pathological conditions associated with this disease.

Spondyloarthritis, Acute Anterior Uveitis, and Fungi: Updating the Catterall-King Hypothesis

Spondyloarthritis is a common type of arthritis which affects mostly adults. It consists of idiopathic chronic inflammation of the spine, joints, eyes, skin, gut, and prostate. Inflammation is often asymptomatic, especially in the gut and prostate. The HLA-B*27 allele group, which presents intracellular peptides to CD8+ T cells, is by far the strongest risk factor for spondyloarthritis. The precise mechanisms and antigens remain unknown. In 1959, Catterall and King advanced a novel hypothesis explaining the etiology of spondyloarthritis: an as-yet-unrecognized sexually acquired microbe would be causing all spondyloarthritis types, including acute anterior uveitis. Recent studies suggest an unrecognized sexually acquired fungal infection may be involved in prostate cancer and perhaps multiple sclerosis. This warrants reanalyzing the Catterall-King hypothesis based on the current literature. In the last decade, many links between spondyloarthritis and fungal infections have been found. Antibodies against the fungal cell wall component mannan are elevated in spondyloarthritis. Functional polymorphisms in genes regulating the innate immune response against fungi have been associated with spondyloarthritis (CARD9 and IL23R). Psoriasis and inflammatory bowel disease, two common comorbidities of spondyloarthritis, are both strongly associated with fungi. Evidence reviewed here lends credence to the Catterall-King hypothesis and implicates a common fungal etiology in prostate cancer, benign prostatic hyperplasia, multiple sclerosis, psoriasis, inflammatory bowel disease, and spondyloarthritis. However, the evidence available at this time is insufficient to definitely confirm this hypothesis. Future studies investigating the microbiome in relation to these conditions should screen specimens for fungi in addition to bacteria. Future clinical studies of spondyloarthritis should consider antifungals which are effective in psoriasis and multiple sclerosis, such as dimethyl fumarate and nystatin.

Differentially expressed mRNAs, lncRNAs, and miRNAs with associated co-expression and ceRNA networks in ankylosing spondylitis

Ankylosing spondylitis (AS) is a chronic autoimmune disease characterized by systemic inflammation and pathological osteogenesis. However, the genetic etiology of AS remains largely unknown. This study aimed to explore the potential role of coding and noncoding genes in the genetic mechanism of AS. Using microarray analyses, this study comprehensively compared lncRNA, microRNA, and mRNA profiles in hip joint ligament tissues from patients with AS and controls. A total of 661 lncRNAs, 574 mRNAs, and 22 microRNAs were differentially expressed in patients with AS compared with controls. Twenty-two of these genes were then validated using real-time polymerase chain reaction. Gene ontology and pathway analyses were performed to explore the principal functions of differentially expressed genes. The pathways were involved mainly in immune regulation, intercellular signaling, osteogenic differentiation, protein synthesis, and degradation. Gene signal transduction network, coding-noncoding co-expression network, and competing endogenous RNA expression network were constructed using bioinformatics methods. Then, two miRNAs, miR-17-5p and miR-27b-3p, that could increase the osteogenic differentiation potentials of ligament fibroblasts were identified. Finally, differentially expressed, five lncRNAs, four miRNAs, and five mRNAs were validated using quantitative real-time polymerase chain reaction. These results suggested that mRNAs, lncRNAs, and microRNAs were involved in AS pathogenesis. The findings might help characterize the pathogenesis of AS and provide novel therapeutic targets for patients with AS in the future.

Quantitative metagenomics reveals unique gut microbiome biomarkers in ankylosing spondylitis

BACKGROUND

The assessment and characterization of the gut microbiome has become a focus of research in the area of human autoimmune diseases. Ankylosing spondylitis is an inflammatory autoimmune disease and evidence showed that ankylosing spondylitis may be a microbiome-driven disease.

RESULTS

To investigate the relationship between the gut microbiome and ankylosing spondylitis, a quantitative metagenomics study based on deep shotgun sequencing was performed, using gut microbial DNA from 211 Chinese individuals. A total of 23,709 genes and 12 metagenomic species were shown to be differentially abundant between ankylosing spondylitis patients and healthy controls. Patients were characterized by a form of gut microbial dysbiosis that is more prominent than previously reported cases with inflammatory bowel disease. Specifically, the ankylosing spondylitis patients demonstrated increases in the abundance of Prevotella melaninogenica, Prevotella copri, and Prevotella sp. C561 and decreases in Bacteroides spp. It is noteworthy that the Bifidobacterium genus, which is commonly used in probiotics, accumulated in the ankylosing spondylitis patients. Diagnostic algorithms were established using a subset of these gut microbial biomarkers.

CONCLUSIONS

Alterations of the gut microbiome are associated with development of ankylosing spondylitis. Our data suggest biomarkers identified in this study might participate in the pathogenesis or development process of ankylosing spondylitis, providing new leads for the development of new diagnostic tools and potential treatments.

Inhibition of Klebsiella pneumoniae growth by selected Australian plants: natural approaches for the prevention and management of ankylosing spondylitis

A wide variety of herbal remedies are used in traditional Australian medicine to treat inflammatory disorders, including autoimmune inflammatory diseases. One hundred and six extracts from 40 native Australian plant species traditionally used for the treatment of inflammation and/or to inhibit bacterial growth were investigated for their ability to inhibit the growth of a microbial trigger for ankylosing spondylitis (K. pneumoniae). Eighty-six of the extracts (81.1%) inhibited the growth of K. pneumoniae. The D. leichardtii, Eucalyptus spp., K. flavescens, Leptospermum spp., M. quinquenervia, Petalostigma spp., P. angustifolium, S. spinescens, S. australe, S. forte and Tasmannia spp. extracts were effective K. pneumoniae growth inhibitors, with MIC values generally <1000 µg/mL. The T. lanceolata peppercorn extracts were the most potent growth inhibitors, with MIC values as low as 16 µg/mL. These extracts were examined by non-biased GC-MS headspace analysis and comparison with a compound database. A notable feature was the high relative abundance of the sesquiterpenoids polygodial, guaiol and caryophyllene oxide, and the monoterpenoids linalool, cineole and α-terpineol in the T. lanceolata peppercorn methanolic and aqueous extracts. The extracts with the most potent K. pneumoniae inhibitory activity (including the T. lanceolata peppercorn extracts) were nontoxic in the Artemia nauplii bioassay. The lack of toxicity and the growth inhibitory activity of these extracts against K. pneumoniae indicate their potential for both preventing the onset of ankylosing spondylitis and minimising its symptoms once the disease is established.

A bicentre retrospective study of features and outcomes of patients with reactive arthritis

OBJECTIVE

Reactive arthritis (ReA) is a sterile arthritis following an extra-articular infection, usually of the gastrointestinal or genitourinary tract. The aim of this study was to assess the incidence and the clinical and therapeutic characteristics of ReA and to compare them with those of a historical cohort. We hypothesised that improved hygiene together with prevention and treatment of sexually transmitted infections may have decreased the incidence of ReA.

METHODS

All patients with ReA diagnosed in the University Hospital Centres of Lyon Sud and Besançon from January 2002 to December 2012 were included in the study retrospectively and were compared with ReA patients diagnosed from January 1986 to December 1996 in the same two hospitals. Medical records were reviewed, clinical features, treatments and outcomes were analysed and diagnoses were compared with international diagnostic criteria.

RESULTS

Twenty-seven patients were included between 2002 and 2012 compared with 31 between 1986 and 1996. The overall incidence of ReA in patients hospitalised in the rheumatology department did not change, although the current evolution is more severe with development of chronic disease in the form of more frequent spondyloarthritis. While the incidence of Chlamydiae trachomatis has decreased, new microbes are now found to be involved.

CONCLUSIONS

ReA still exists and its incidence has been stable over the last 30 years. However, ReA currently more often progress to spondyloarthritis. Our study also highlights the need for diagnostic criteria that accurately detect ReA.

Antibodies Directed against a Peptide Epitope of a Klebsiella pneumoniae-Derived Protein Are Present in Ankylosing Spondylitis

Ankylosing spondylitis (AS) is a chronic inflammatory arthritis of unknown origin. Its autoimmune origin has been suggested but never proven. Several reports have implicated Klebsiella pneumoniae as a triggering or perpetuating factor in AS; however, its role in the disease pathogenesis remains debated. Moreover, despite extensive investigations, a biomarker for AS has not yet been identified. To clarify these issues, we screened a random peptide library with pooled IgGs obtained from 40 patients with AS. A peptide (AS peptide) selected from the library was recognized by serum IgGs from 170 of 200 (85%) patients with AS but not by serum specimens from 100 healthy controls. Interestingly, the AS peptide shows a sequence similarity with several molecules expressed at the fibrocartilaginous sites that are primarily involved in the AS inflammatory process. Moreover, the peptide is highly homologous to a Klebsiella pneumoniae dipeptidase (DPP) protein. The antibody affinity purified against the AS peptide recognizes the autoantigens and the DPP protein. Furthermore, serum IgG antibodies against the Klebsiella DPP121-145 peptide epitope were detected in 190 of 200 patients with AS (95%), 3 of 200 patients with rheumatoid arthritis (1.5%) and only 1 of 100 (1%) patients with psoriatic arthritis. Such reactivity was not detected in healthy control donors. Our results show that antibodies directed against an epitope of a Klebsiella pneumoniae-derived protein are present in nearly all patients with AS. In the absence of serological biomarkers for AS, such antibodies may represent a useful tool in the diagnosis of the disease.

TNF-α Induced the Enhanced Apoptosis of Mesenchymal Stem Cells in Ankylosing Spondylitis by Overexpressing TRAIL-R2

Ankylosing spondylitis (AS) is an autoimmune disease with unknown etiology. Dysregulated mesenchymal stem cells (MSCs) apoptosis may contribute to the pathogenesis of autoimmune diseases. However, apoptosis of MSCs from patients with AS (ASMSCs) has not been investigated yet. The present study aims to assess the apoptosis of bone marrow-derived ASMSCs and to investigate the underlying mechanisms of altered ASMSCs apoptosis. We successfully induced the apoptosis of ASMSCs and MSCs from healthy donors (HDMSCs) using the combination of tumor necrosis factor alpha (TNF-α) and cycloheximide (CHX). We found that ASMSCs treated with TNF-α and CHX showed higher apoptosis levels compared to HDMSCs. During apoptosis, ASMSCs expressed significantly more TRAIL-R2, which activated both the death receptor pathway and mitochondria pathway by increasing the expression of FADD, cleaved caspase-8, cytosolic cytochrome C, and cleaved caspase-3. Inhibiting TRAIL-R2 expression using shRNA eliminated the apoptosis differences between HDMSCs and ASMSCs by partially reducing ASMSCs apoptosis but minimally affecting that of HDMSCs. Furthermore, the expression of FADD, cleaved caspase-8, cytosolic cytochrome C, and cleaved caspase-3 were comparable between HDMSCs and ASMSCs after TRAIL-R2 inhibition. These results indicated that increased TRAIL-R2 expression results in enhanced ASMSCs apoptosis and may contribute to AS pathogenesis.

PROBIOTICS - A PROBABLE THERAPEUTIC AGENT FOR SPONDYLOARTHROPATHY

Spondyloarthropathy (SpA) or spondyloarthrosis refers to any joint disease of the vertebral column. Among the entities of SpA, ankylosing spondylitis has drawn the attention of some researchers, because of its specific mechanism of disease progression. It has been studied earlier that its progression is due to the presence of HLA (human leukocyte antigen) - B27. It shows molecular similarity and immunological cross-reactivity with some of the gut microbiome. Since SpA could be treated or its symptoms could be lessen by medications, but medications itself show many side effects and other complications. Probiotic- being the natural product has been found to be effective against many SpA entities, including Ankylosing Spondylitis. It alters gut microflora somehow in such a way that it helps in reducing the predisposition of any factor to SpA. Here we consider the complex relationship between SpA pathogenesis and gut microbes; with discussion that how use of probiotics as an alternative drug therapy may treat or reduce the progression of SpA, which could be a better future target to treat SpA entities.

Are Systematic Screening for Vitamin D Deficiency and Vitamin D Supplementation Currently Feasible for Ankylosing Spondylitis Patients?

Beyond its role in calcium and phosphorus metabolism for healthy bone mineralization, there is increasing awareness for vitamin D contribution in modulation of immune reactions. Given that ankylosing spondylitis (AS) is a chronic inflammatory disease involving excess immune/inflammatory activity and posing great therapeutic challenges, it is conceivable to claim that vitamin D treatment may be a safe and effective treatment to influence or modify the primary disease and its related comorbidities. Nevertheless, consistent body of research supporting this hypothesis is still lacking. In this paper, we examine whether systematic screening and treatment for vitamin D deficiency are feasible at present. We will review the immunomodulatory role of vitamin D and its contribution in initiation and progression of AS, as well as how they would determine the occurrence of comorbid conditions. Our conclusion is that despite the overwhelmed interest about vitamin D treatment in AS patients, systematic screening and treatment for vitamin D deficiency of all AS patients are not feasible as yet. This stresses the need for further extensive well-designed research to prove vitamin D efficacy in AS beyond bone protection. And if utility is proven, personalized treatment regimes, duration of treatment, and threshold values for vitamin D should be provided.

Gut microbiome in children with enthesitis-related arthritis in a developing country and the effect of probiotic administration

In Asia, enthesitis-related arthritis (ERA) is the most frequent category of juvenile idiopathic arthritis. ERA has a strong association with human leucocyte antigen (HLA)-B27 and subclinical gut inflammation. In an HLA-B27 transgenic rat model, the presence of Bacteroides bacteria in the gut appears to cause spondyloarthropathy (SpA). Thus, we studied gut microbiota in children with ERA. Stool specimens from 33 patients with ERA and 14 age-matched healthy controls were studied; none had any gastrointestinal symptom, or had received a drug known to affect gut motility or microbiota in the preceding 6 weeks. From each specimen, a cDNA library for the V3 region of bacterial 16S rRNA was subjected to high-throughput, massively parallel sequencing. Relationship of the specimens was studied using principal co-ordinate analysis (PCoA), and abundances of various bacterial taxa and alpha diversity were compared between groups. In eight patients, a repeat faecal specimen was studied after 12 weeks of probiotic therapy. The 55 specimens yielded a median (range) of 397 315 (102 093-1 502 380) high-quality reads each. In PCoA, gut microbiota from ERA showed a wider dispersion than those from controls. In patients, families Bacteroidaceae and Enterobacteriaceae were more abundant and Prevotellaceae were less abundant than in controls. Also, genera Bacteroides, Entercoccus and Klebsiella were over-represented and genus Prevotella was under-represented in ERA patients. Probiotic therapy led to a non-significant increase in Prevotellaceae. Patients with ERA have a dysbiosis in the gut, with increased abundance of Bacteroides and reduction of Prevotella. Probiotic supplementation in a subset of patients did not reverse these changes significantly.

Whole-Genome Comparative Analysis of Two Carbapenem-Resistant ST-258 Klebsiella pneumoniae Strains Isolated during a North-Eastern Ohio Outbreak: Differences within the High Heterogeneity Zones

Klebsiella pneumoniae has become one of the most dangerous causative agents of hospital infections due to the acquisition of resistance to carbapenems, one of the last resort families of antibiotics. Resistance is usually mediated by carbapenemases coded for by different classes of genes. A prolonged outbreak of carbapenem-resistant K. pneumoniae infections has been recently described in northeastern Ohio. Most strains isolated from patients during this outbreak belong to MLST sequence type 258 (ST258). To understand more about this outbreak two isolates (strains 140 and 677), one of them responsible for a fatal infection, were selected for genome comparison analyses. Whole genome map and sequence comparisons demonstrated that both strains are highly related showing 99% average nucleotide identity. However, the genomes differ at the so-called high heterogeneity zone (HHZ) and other minor regions. This study identifies the potential value of the HHZ as a potential marker for K. pneumoniae clinical and epidemiological studies.

Imbalance Between Bone Morphogenetic Protein 2 and Noggin Induces Abnormal Osteogenic Differentiation of Mesenchymal Stem Cells in Ankylosing Spondylitis

OBJECTIVE

To study the osteogenic differentiation capacity of bone marrow-derived mesenchymal stem cells (BM-MSCs) from patients with ankylosing spondylitis (AS) and to investigate the mechanisms of abnormal osteogenic differentiation of BM-MSCs in AS.

METHODS

BM-MSCs from healthy donors (HD-MSCs) and patients with AS (AS-MSCs) were cultured in osteogenic differentiation medium for 0-21 days, after which their osteogenic differentiation capacity was determined using alizarin red S and alkaline phosphatase assays. Gene expression levels of osteoblastic markers and related cytokines were detected by high-throughput quantitative reverse transcription-polymerase chain reaction. Enzyme-linked immunosorbent assay was performed to detect protein levels of bone morphogenetic protein 2 (BMP-2) and Noggin in the cell culture supernatant. The activation of Smad1/5/8 and MAPK signaling pathways was measured by Western blotting. The balance between BMP-2 and Noggin expression was regulated using lentiviruses encoding short hairpin RNA and exogenous Noggin, respectively, which enabled evaluation of how this balance affected osteogenic differentiation of AS-MSCs.

RESULTS

AS-MSCs outperformed HD-MSCs in osteogenic differentiation capacity. During osteogenic differentiation, AS-MSCs secreted more BMP-2 but less Noggin, accompanied by an overactivation of Smad1/5/8 and ERK-1/2. When the Noggin concentration was increased or BMP-2 expression was inhibited, the abnormal osteogenic differentiation of AS-MSCs was rectified. In addition, the balance between BMP-2 and Noggin secretion was restored.

CONCLUSION

The results of this study demonstrate that an imbalance between BMP-2 and Noggin secretion induces abnormal osteogenic differentiation of AS-MSCs. These findings reveal a mechanism of pathologic osteogenesis in AS and provide a new perspective on inhibiting pathologic osteogenesis by regulating the balance between BMP-2 and Noggin.

Differential Expression Profiles of Long Noncoding RNA and mRNA of Osteogenically Differentiated Mesenchymal Stem Cells in Ankylosing Spondylitis

OBJECTIVE

We previously demonstrated that mesenchymal stem cells (MSC) from patients with ankylosing spondylitis (AS; ASMSC) have a greater osteogenic differentiation capacity than MSC from healthy donors (HDMSC) and that this difference underlies the pathogenesis of pathological osteogenesis in AS. Here we compared expression levels of long noncoding RNA (lncRNA) and mRNA between osteogenically differentiated ASMSC and HDMSC and explored the precise mechanism underlying abnormal osteogenic differentiation in ASMSC.

METHODS

HDMSC and ASMSC were induced with osteogenic differentiation medium for 10 days. Microarray analyses were then performed to identify lncRNA and mRNA differentially expressed between HDMSC and ASMSC, which were then subjected to bioinformatics analysis and confirmed by quantitative real-time PCR (qRT-PCR) assays. In addition, coding-non-coding gene co-expression (CNC) networks were constructed to examine the relationships between the lncRNA and mRNA expression patterns.

RESULTS

A total of 520 lncRNA and 665 mRNA were differentially expressed in osteogenically differentiated ASMSC compared with HDMSC. Bioinformatics analysis revealed 64 signaling pathways with significant differences, including transforming growth factor-β signaling. qRT-PCR assays confirmed the reliability of the microarray data. The CNC network indicated that 4 differentially expressed lncRNA, including lnc-ZNF354A-1, lnc-LIN54-1, lnc-FRG2C-3, and lnc-USP50-2 may be involved in the abnormal osteogenic differentiation of ASMSC.

CONCLUSION

Our study characterized the differential lncRNA and mRNA expression profiles of osteogenically differentiated ASMSC and identified 4 lncRNA that may participate in the abnormal osteogenic differentiation of ASMSC. These results provide insight into the pathogenesis of pathological osteogenesis in AS.

Spondyloarthritis and the microbiome: new insights from an ancient hypothesis

The human microbiome, which represents the total collection of microorganisms (and their genes) inhabiting the human body, has increasingly been recognized as a potential key factor in the development of autoimmune disease. Multiple studies suggest that the microbiome has significant influence on immune homeostasis, while disruptions in local microbiome composition can result in a heightened systemic inflammatory response. The intestinal microbiome, in particular, harbors the densest assembly of bacteria and appears to influence the immune system in the context of inflammatory arthropathies. Although studies are still sparse, this review will examine the role of the microbiome in the pathogenesis of spondyloarthritis (SpA), particularly in enteropathic arthritis (EA), reactive arthritis (ReA), ankylosing spondylitis (AS), and psoriatic arthritis (PsA).

The intestinal microbiome in human disease and how it relates to arthritis and spondyloarthritis

Humans and microbes have developed a symbiotic relationship over time, and alterations in this symbiotic relationship have been linked to several immune mediated diseases such as inflammatory bowel disease, type 1 diabetes and spondyloarthropathies. Improvements in sequencing technologies, coupled with a renaissance in 16S rRNA gene based community profiling, have enabled the characterization of microbiomes throughout the body including the gut. Improved characterization and understanding of the human gut microbiome means the gut flora is progressively being explored as a target for novel therapies including probiotics and faecal microbiota transplants. These innovative therapies are increasingly used for patients with debilitating conditions where conventional treatments have failed. This review discusses the current understanding of the interplay between host genetics and the gut microbiome in the pathogenesis of spondyloarthropathies, and how this may relate to potential therapies for these conditions.

Human Microbiome: When a Friend Becomes an Enemy

The microorganisms that inhabit humans are very diverse on different body sites and tracts. Each specific niche contains a unique composition of the microorganisms that are important for a balanced human physiology. Microbial cells outnumber human cells by tenfold and they function as an invisible organ that is called the microbiome. Excessive use of antibiotics and unhealthy diets pose a serious danger to the composition of the microbiome. An imbalance in the microbial community may cause pathological conditions of the digestive system such as obesity, cancer and inflammatory bowel disease; of the skin such as atopic dermatitis, psoriasis and acne and of the cardiovascular system such as atherosclerosis. An unbalanced microbiome has also been associated with neurodevelopmental disorders such as autism and multiple sclerosis. While the microbiome has a strong impact on the development of the host immune system, it is suspected that it can also be the cause of certain autoimmune diseases, including diabetes or rheumatoid arthritis. Despite the enormous progress in the field, the interactions between the human body and its microbiome still remain largely unknown. A better characterization of the interactions may allow for a deeper understanding of human disease states and help to elucidate a possible association between the composition of the microbiome and certain pathologies. This review focuses on general findings that are related to the area and provides no detailed information about the case of study. The aim is to give some initial insight on the studies of the microbiome and its connection with human health.

Individuality, phenotypic differentiation, dormancy and 'persistence' in culturable bacterial systems: commonalities shared by environmental, laboratory, and clinical microbiology

For bacteria, replication mainly involves growth by binary fission. However, in a very great many natural environments there are examples of phenotypically dormant, non-growing cells that do not replicate immediately and that are phenotypically 'nonculturable' on media that normally admit their growth. They thereby evade detection by conventional culture-based methods. Such dormant cells may also be observed in laboratory cultures and in clinical microbiology. They are usually more tolerant to stresses such as antibiotics, and in clinical microbiology they are typically referred to as 'persisters'. Bacterial cultures necessarily share a great deal of relatedness, and inclusive fitness theory implies that there are conceptual evolutionary advantages in trading a variation in growth rate against its mean, equivalent to hedging one's bets. There is much evidence that bacteria exploit this strategy widely. We here bring together data that show the commonality of these phenomena across environmental, laboratory and clinical microbiology. Considerable evidence, using methods similar to those common in environmental microbiology, now suggests that many supposedly non-communicable, chronic and inflammatory diseases are exacerbated (if not indeed largely caused) by the presence of dormant or persistent bacteria (the ability of whose components to cause inflammation is well known). This dormancy (and resuscitation therefrom) often reflects the extent of the availability of free iron. Together, these phenomena can provide a ready explanation for the continuing inflammation common to such chronic diseases and its correlation with iron dysregulation. This implies that measures designed to assess and to inhibit or remove such organisms (or their access to iron) might be of much therapeutic benefit.

Individuality, phenotypic differentiation, dormancy and 'persistence' in culturable bacterial systems: commonalities shared by environmental, laboratory, and clinical microbiology

For bacteria, replication mainly involves growth by binary fission. However, in a very great many natural environments there are examples of phenotypically dormant, non-growing cells that do not replicate immediately and that are phenotypically 'nonculturable' on media that normally admit their growth. They thereby evade detection by conventional culture-based methods. Such dormant cells may also be observed in laboratory cultures and in clinical microbiology. They are usually more tolerant to stresses such as antibiotics, and in clinical microbiology they are typically referred to as 'persisters'. Bacterial cultures necessarily share a great deal of relatedness, and inclusive fitness theory implies that there are conceptual evolutionary advantages in trading a variation in growth rate against its mean, equivalent to hedging one's bets. There is much evidence that bacteria exploit this strategy widely. We here bring together data that show the commonality of these phenomena across environmental, laboratory and clinical microbiology. Considerable evidence, using methods similar to those common in environmental microbiology, now suggests that many supposedly non-communicable, chronic and inflammatory diseases are exacerbated (if not indeed largely caused) by the presence of dormant or persistent bacteria (the ability of whose components to cause inflammation is well known). This dormancy (and resuscitation therefrom) often reflects the extent of the availability of free iron. Together, these phenomena can provide a ready explanation for the continuing inflammation common to such chronic diseases and its correlation with iron dysregulation. This implies that measures designed to assess and to inhibit or remove such organisms (or their access to iron) might be of much therapeutic benefit.

Whole Genome Expression Profiling and Signal Pathway Screening of MSCs in Ankylosing Spondylitis

The pathogenesis of dysfunctional immunoregulation of mesenchymal stem cells (MSCs) in ankylosing spondylitis (AS) is thought to be a complex process that involves multiple genetic alterations. In this study, MSCs derived from both healthy donors and AS patients were cultured in normal media or media mimicking an inflammatory environment. Whole genome expression profiling analysis of 33,351 genes was performed and differentially expressed genes related to AS were analyzed by GO term analysis and KEGG pathway analysis. Our results showed that in normal media 676 genes were differentially expressed in AS, 354 upregulated and 322 downregulated, while in an inflammatory environment 1767 genes were differentially expressed in AS, 1230 upregulated and 537 downregulated. GO analysis showed that these genes were mainly related to cellular processes, physiological processes, biological regulation, regulation of biological processes, and binding. In addition, by KEGG pathway analysis, 14 key genes from the MAPK signaling and 8 key genes from the TLR signaling pathway were identified as differentially regulated. The results of qRT-PCR verified the expression variation of the 9 genes mentioned above. Our study found that in an inflammatory environment ankylosing spondylitis pathogenesis may be related to activation of the MAPK and TLR signaling pathways.

The potential of selected South African plants with anti-Klebsiella activity for the treatment and prevention of ankylosing spondylitis

A wide variety of herbal remedies are used in traditional African medicine to treat inflammatory disorders, including some autoimmune diseases. Thirty-four extracts from 13 South African plant species traditionally used for the treatment of inflammation were investigated for their ability to control a microbial trigger for ankylosing spondylitis (Klebsiella pneumoniae). Twenty-six of the extracts (76.5%) inhibited the growth of K. pneumoniae. Methanol and water extracts of Ballota africana, Carpobrotus edulis leaves, Kigellia africana, Lippia javanica, Pelargonium fasiculata, Syzygium cordatum (including bark), Terminalia pruinoides and Terminalia sericea were effective K. pneumoniae inhibitors, with MIC values <1000 µg/ml. The roots of Tulbaghia violaceae and bark from Warburgia salutaris also demonstrated efficacy. The most potent extracts were examined by RP-HPLC and UV-Vis spectroscopy for the presence of resveratrol. Methanolic extracts of B. africana, C. edulis leaves, L. javanica, T. pruinoides and T. sericea, as well as aqueous B. africana, T. pruinoides and T. sericea extracts, displayed peaks with retention times and UV-Vis spectra consistent with the presence of resveratrol. Resveratrol was generally a minor component, indicating that resveratrol was not solely responsible for the anti-Klebsiella growth inhibitory properties. Plant extracts with K. pneumoniae inhibitory activity were either non-toxic, or of low toxicity in the Artemia (brine shrimp) nauplii bioassay. Their low toxicity and antibiotic bioactivity against K. pneumoniae indicate their potential for both preventing the onset of ankylosing spondylitis and minimising its symptoms once the disease is established.

The role of the gut and microbes in the pathogenesis of spondyloarthritis

The intestinal microbiota is firmly implicated not only in the pathogenesis of inflammatory bowel disease (IBD) but increasingly also in the development of inflammation at extraintestinal tissue sites. Significant clinical, genetic, immunological, and microbiological overlap exists between IBD and spondyloarthritis (SpA), which indicates that pathophysiological mechanisms are shared between these diseases and may center on the intestinal microbiota. Recently, culture-independent techniques have enabled the microbiota in health and disease to be described in increasing detail. Moreover, functional studies have identified myriad host effector and regulatory pathways that shape or are shaped by this microbial community. We consider the complex relationship between SpA pathogenesis and gut microbes, with a discussion of how manipulation of the gut microbiota itself may be a promising future target for SpA therapy.

Raised incidence of ankylosing spondylitis among Inuit populations could be due to high HLA-B27 association and starch consumption

Ankylosing spondylitis (AS) is a chronic inflammatory arthritis mainly affecting the spinal joints. It would appear that the most likely causative agent in the development of AS is an environmental factor in the genetically susceptible, HLA-B27 positive, individuals. Extensive data from several countries support the notion that Klebsiella pneumonia bacteria are the most likely culprit in the causation of AS. These microbes possess antigens which resemble HLA-B27 and spinal collagens. Increased intake of high-starch diet is directly proportional to the gut-associated bacterial load, especially in the large intestine, and among these microbial agents, Klebsiella is considered as one of the main constituting components. Therefore, a low-starch diet intake alongside the currently used medical therapeutic modalities could be beneficial in the management of patients with early AS. It is suggested that a change in the dietary habits from high protein, low-starch marine components to the Westernized high-starch diet among the Inuit peoples of Alaska and Canada could be considered as one of the main contributing factors in the increased prevalence of AS during the last few decades within this genetically unmixed native population.