BMP2 variants in the risk of ankylosing spondylitis

The purpose of the study was to explore the genetic effects of bone morphogenetic protein (BMP2) polymorphisms on the susceptibility to ankylosing spondylitis (AS) in Chinese Han population. The case-control study included 120 AS cases and 110 healthy controls. Hardy-Weinberg equilibrium test was performed in control group. BMP2 rs235768 and rs3178250 polymorphisms were analyzed by polymerase chain reaction and direct sequencing. Additionally, the χ² test was used to estimate association strength between BMP2 genetic polymorphisms and AS susceptibility, and the results were assessed via odds ratio (OR) with the corresponding 95% confidence interval (95%CI). Results adjustment was performed using logistic regression analysis. AA, AT, TT genotype and A, T allele frequencies of BMP2 rs235768 polymorphism presented no significant differences between case and control groups (P > .05 for all). TC genotype of rs3178250 polymorphism showed significantly higher in case group than that in control group (P = .048). After adjusting, TC genotype was a risk factor for AS (OR = 2.095; 95%CI = 1.086-4.038; P = .027). BMP2 rs3178250 polymorphism may increase individual susceptibility to AS in Chinese Han population.     

吉林人群强直性脊柱炎6号染色体短臂上的HLA区域遗传易感基因定位研究

为了寻找中国人群中与强直性脊柱炎相关的新的易感基因及其所在位置, 在与强直性脊柱炎强连锁的6 号染色体短臂上的HLA基因区域内选取11个SNPs多态位点, 通过对中国吉林地区79名AS患者和132名正常对照者进行case-control分析, 发现TNF-a -850处TT突变基因型在AS组中的分布高于正常对照组（P=0.027）, 突变型T等位基因在AS组和正常对照组中的分布差异更为显著（P=0.002）。通过多位点之间的连锁不平衡分析发现, LTA基因、TNF-a基因、LST1基因和NCR3基因中的 5个SNPs多态位点之间存在连锁不平衡, 范围是15 kb, 在这5个SNPs多态位点组成的单体型中, TCTTC单体型在AS组和正常对照组中的分布有显著差异（c2=7.406, P=0.0065）,并且该单体型中含有具有统计学意义的TNF-a –850的突变型等位基因T。提示在LTA、TNF-a、NCR3和LST1 这4个基因构成的15 kb范围内可能存在增加AS患病易感性的位点, 可能是TNF-a –850 C→T突变, 也可能是在TNF-a –850附近的其他位点。     

Novel non-HLA-susceptible regions determined by meta-analysis of four genomewide scans for ankylosing spondylitis

We identified novel non-HLA-susceptible regions for ankylosing spondylitis (AS) by applying the genome-search-metaanalysis (GSMA) method to combine the previous four AS genomewide scan studies including 479 families with 1175 affected individuals. Three original genomescans were mainly analysed for Caucasian families and one analysed for Han Mongolian families. Ten bins had both Psumrnk and Pord <0.05, suggesting these bins most likely contain AS-linked loci. The 10 bins are 6.2, 16.3, 6.1, 3.3, 6.3, 16.4, 10.5, 17.1, 2.5 and 2.9. The most significant result of linkage was on chromosome 6p22.3-p21.1 (bin 6.2, Psumrnk <0.000417), where HLA loci are located. By addition of a genome scan of Chinese origin, our GSMA result further confirmed the HLA loci as the greatest susceptible region to AS and suggested that non-HLA loci chromosome 16q, 3p, 10q, 2p, 2q and 17p, may also contain AS-linked loci. The novel loci identified in our result give hints to further studies.     

Long-term outcome of patients with active ankylosing spondylitis with etanercept-sustained efficacy and safety after seven years

Introduction

Data from clinical studies on the long-term efficacy and safety of anti-tumor necrosis factor (TNF)-α therapy in patients with ankylosing spondylitis (AS) are scarce. This is the first report on continuous treatment with the TNFα fusion protein etanercept over seven years (y).

Methods

Overall, 26 patients with active AS were initially treated with etanercept 2 × 25 mg s.c./week with no concomitant disease modifying anti-rheumatic drugs (DMARDs) or steroids. The clinical response was assessed by standardized parameters. The primary outcome was the proportion of patients in the Spondyloarthritis International Society (ASAS) partial remission at seven years. AS disease activity scores (ASDAS) for status and improvement were compared to conventional outcome measures.

Results

Overall, 21/26 patients (81%) completed two years of treatment and 16/26 patients (62%) completed seven years. In the completer analysis, 31% patients were in ASAS partial remission at seven years, while 44% patients showed an ASDAS inactive disease status. Mean Bath AS activity index (BASDAI) scores, which were elevated at baseline (6.3 ± 0.9), showed constant improvement and remained low: 3.1 ± 2.5 at two years and 2.5 ± 2.2 at seven years, while ASDAS also improved (3.9 ± 0.7 at baseline, 1.8 ± 0.9 at two years, 1.6 ± 0.8 at seven years), all P <0.001. From the 10 dropouts, only 5 patients discontinued treatment due to adverse events. Patients who completed the study had lower baseline Bath AS function index (BASFI) scores vs. patients who discontinued. No other clinical parameter at baseline could predict any long-term outcome.

Conclusions

This study confirms the clinical efficacy and safety of etanercept in patients with active AS over seven years of continuous treatment. After seven years, more than half of the initially treated patients remained on anti-TNF therapy, and one-third were in partial remission.

Trial Registration

ClinicalTrials.gov: {"type":"clinical-trial","attrs":{"text":"NCT01289743","term_id":"NCT01289743"}}NCT01289743     

与宁夏人群强直性脊柱炎关联的新基因淋巴毒素-α(LTA)的识别

淋巴毒素-α(Lymphotoxin-alpha,LTA)基因与系统性红斑狼疮、银屑病及类风湿性关节炎的遗传性有关,但目前还未有关于LTA基因与强直性脊柱炎(Ankylosing spondylitis,AS)关联的报道。文章采用病例-对照设计,在宁夏人群中对人类白细胞抗原(Human leukocyte antigen,HLA)的Ⅲ类基因约58 kb区域进行了高密度标志的基因组扫描,在33个SNPs及其单倍型中,仅定位于LTA基因中的SNPs组成的TCC单倍型的分布在病例-对照间比较有统计学意义(P=0.0005)。在宁夏群体(病例组:300,对照组:385)中发现,LTA基因中的rs909253 T/C多态性在AS患者中出现的频率显著高于正常对照(28.5%vs 19.7%,P=2×10-6)。结果表明LTA基因变异和AS易感性之间存在相关性,由此识别LTA基因可能与宁夏人群AS关联。     

强直性脊柱炎患者咽部菌群变化

目的 探讨强直性脊柱炎患者的咽部菌群变化。方法 筛选入组7例强直性脊柱炎患者和7例健康者咽拭子样本,提取咽部DNA,扩增16S rRNA基因,在Illumina平台测序,对测序结果进行生物信息学分析。结果 从ACE指数、Chao1指数、Shannon指数和Simpson指数综合来看强直性脊柱炎患者的咽部菌群Alpha多样性差异不大。Beta多样性分析显示两组研究对象咽部菌群样本可被区分。强直性脊柱炎患者咽部菌群组成和含量发生显著改变,主要变化包括：拟杆菌门（Bacteroidetes）和放线菌门（Actinobacteria）显著降低。拟杆菌门中普雷沃杆菌属（Prevotella）相关的纲目科属水平都显著降低。放线菌门变化落实到属水平,放线菌属（Actinomyces）显著降低,丙酸杆菌属（Propionibacterium）和棒状杆菌属（Corynebacterium）显著增高。厚壁菌门（Firmicutes）中,芽胞杆菌纲（Bacilli）所属的与链球菌属（Streptococcus）相关的纲目科属水平显著增加,而梭状芽胞杆菌纲（Clostridia）包含的韦荣球菌属（Veillonella）、消化球菌属（Peptococcus）显著下降。此外,变形菌门中出现弧菌属（Vibrio）的增加和弯曲菌属（Campylobacter）的降低等变化。结论 强直性脊柱炎患者（本次研究样本）的咽部菌群出现紊乱,以普雷沃杆菌属、放线菌属、韦荣球菌属、消化球菌属和弯曲菌属等显著降低,丙酸杆菌属、棒状杆菌属、链球菌属和弧菌属等显著增加为主要特征。     

microRNA-96 promotes osteoblast differentiation and bone formation in ankylosing spondylitis mice through activating the Wnt signaling pathway by binding to SOST

Ankylosing spondylitis (AS) refers to a type of arthritis manifested with chronic inflammation of spine joints. microRNAs (MiRNAs) have been identified as new therapeutic targets for inflammatory diseases. In this study, we evaluated the influence of microRNA-96 (miR-96) on osteoblast differentiation together with bone formation in a murine model of AS. The speculated relationship that miR-96 could bind to sclerostin (SOST) was verified by dual luciferase reporter assay. After successful model establishment, the mice with AS and osteoblasts isolated from mice with AS were treated with mimics or inhibitors of miR-96, or DKK-1 (a Wnt signaling inhibitor). The effects of gain- or loss-of-function of miR-96 on the inflammatory cytokine release (IL-6, IL-10, and TNF-α), alkaline phosphatase (ALP) activity, calcium nodule formation, along with the viability of osteoblasts were determined. It was observed that miR-96 might target and regulate SOST. Besides, miR-96 was expressed at a high level in AS mice while SOST expressed at a low level. TOP/FOP-Flash luciferase reporter assay confirmed that miR-96 activated the Wnt signaling pathway. Moreover, AS mice overexpressing miR-96 exhibited increased contents of IL-6, IL-10 and TNF-α, ALP activity, calcium nodule numbers, and viability of osteoblasts. In contrast, inhibition of miR-96 resulted in suppression of the osteoblast differentiation and bone formation. In conclusion, the study implicates that overexpressing miR-96 could improve osteoblast differentiation and bone formation in AS mice via Wnt signaling pathway activation, highlighting a potential new target for AS treatment.     

Markers of intestinal inflammation in patients with ankylosing spondylitis: a pilot study

Introduction

Inflammatory bowel disease (IBD) and ankylosing spondylitis (AS) are similar chronic inflammatory diseases whose definitive etiology is unknown. Following recent clinical and genetic evidence supporting an intertwined pathogenic relationship, we conducted a pilot study to measure fecal calprotectin (fCAL) and IBD-related serologies in AS patients.

Methods

Consecutive AS patients were recruited from a long-term prospectively collected longitudinal AS cohort at Cedars-Sinai Medical Center. Controls were recruited from Cedars-Sinai Medical Center employees or spouses of patients with AS. Sera were tested by ELISA for IBD-associated serologies (antineutrophil cytoplasmic antibodies (ANCA), anti-Saccharomyces cerevisiae antibody IgG and IgA, anti-I2, anti-OmpC, and anti-CBir1). The Bath Ankylosing Spondylitis Disease Activity Index, the Bath Ankylosing Spondylitis Functional Index, and the Bath Ankylosing Spondylitis Radiology Index were completed for AS patients.

Results

A total of 81 subjects (39 AS patients and 42 controls) were included for analysis. The average age of AS patients was 47 years and the average disease duration was 22 years. AS patients were predominantly male; 76% were HLA-B27-positive. Median fCAL levels were 42 μg/g and 17 μg/g in the AS group and controls, respectively (P < 0.001). When using the manufacturer''s recommended cutoff value for positivity of 50 μg/g, stool samples of 41% of AS patients and 10% of controls were positive for fCAL (P = 0.0016). With the exception of ANCA, there were no significant differences in antibody levels between patients and controls. Median ANCA was 6.9 ELISA units in AS patients and 4.3 ELISA units in the controls. Among AS patients stratified by fCAL level, there were statistically significant differences between patients and controls for multiple IBD-associated antibodies.

Conclusion

Calprotectin levels were elevated in 41% of patients with AS with a cutoff value for positivity of 50 μg/g. fCAL-positive AS patients displayed higher medians of most IBD-specific antibodies when compared with healthy controls or fCAL-negative AS patients. Further studies are needed to determine whether fCAL can be used to identify and characterize a subgroup of AS patients whose disease might be driven by subclinical bowel inflammation.     

Association of IFN‐γ polymorphisms with ankylosing spondylitis risk

The case‐control study was designed to investigate the genetic effects of interferon‐gamma (IFN‐γ) rs2069727 and rs1861494 polymorphisms on ankylosing spondylitis (AS) susceptibility in a Chinese Han population. Blood samples were collected from 108 AS patients and 110 healthy controls. IFN‐γ polymorphisms were genotyped by polymerase chain reaction‐restriction fragment length polymorphism (PCR‐RFLP). Hardy‐Weinberg equilibrium (HWE) test was performed in control group. Odds ratios (OR) with 95% confidence intervals (95% CI) were calculated using chi‐square test to evaluate the association between AS susceptibility and IFN‐γ polymorphisms, and the results were adjusted by logistic regressive analysis. The frequency of rs2069727 CC genotype was much higher in cases than that in controls, suggested its significant association with increased AS risk (adjusted OR = 5.899, 95% CI = 1.563‐22.261; P = .009). In addition, C allele also showed close association with increased risk of AS (adjusted OR = 2.052, 95% CI = 1.286‐1.704, P  = 0 .003). While the genotype and allele frequencies of IFN‐γ rs1861494 polymorphism were not significantly different between patients and controls (P  > 0.05 for all), IFN‐γ rs2069727 polymorphism is significantly associated with increased AS risk in a Chinese Han Population.     

Identification of disease-associated proteins by proteomic approach in ankylosing spondylitis

Ankylosing spondylitis (AS) is a chronic systemic inflammatory disorder of the axial skeleton and shows significant inherited susceptibility. Auto-immune responses have been traditionally considered as a putative pathogenetic event in AS. However, no consistent self-antigen has been identified to responsible for the disorders in AS to this day. In this study, serum protein profiles of AS patients and healthy controls from a large Chinese AS family were investigated by two dimensional electrophoresis analysis. A group of four highly expressed protein spots was observed in all AS patients' profiles and subsequently identified as isoforms of haptoglobin precursor (pre-Hp) by ESI-Q-TOF MS/MS. Increased expression of haptoglobin precursor were also observed in sera of sporadic AS patients. Moreover, bioinformatics analysis revealed epitopes derived from haptoglobin precursor with high affinity binding to HLA-B( *)2705, a primary subtype associated with AS. These results indicate that pre-Hp may be involved in the pathogenesis of AS.     

肠道微生态失调与强直性脊柱炎发生发展的相关性分析

强直性脊柱炎（ankylosing spondylitis,AS）发病较为隐蔽,机制复杂。目前临床诊断方法具有明显的滞后性,因此寻求更为快速、准确的早期诊断指标对缓解甚至治愈AS显得极为重要。现有的大量研究显示肠道微生物与AS关系密切,且可能通过肠道微生物与遗传因子HLA-B27相互作用、肠道通透性改变介导的肠黏膜IgA免疫应答和炎性因子的过度表达、肠—脑轴、肠道微生物之间的相互作用等机制导致AS的发生发展。本文就AS患者肠道微生物变化及肠道微生态失调与AS的相关性作一综述。     

Elevated serum anti-flagellin antibodies implicate subclinical bowel inflammation in ankylosing spondylitis: an observational study

Introduction

Ankylosing spondylitis (AS) and inflammatory bowel disease (IBD) share genetic and clinical features. IBD is associated with the presence of antibodies to a variety of commensal microorganisms including anti-Saccharomyces cerevesiae antibodies (ASCA), antineutrophil cytoplasmic antibodies (ANCA), anti-I2 (associated with anti-Pseudomonas activity), anti-Eschericia coli outer membrane porin C (anti-OmpC) and anti-flagellin antibodies (anti-CBir1). Subclinical intestinal inflammation may be present in up to 65% of patients with AS. This study evaluated the presence of antimicrobial antibodies in patients with AS alone, patients with AS and concomitant IBD (AS-IBD) and a control group of patients with mechanical back pain (MBP).

Methods

Sera were tested by ELISA for ASCA IgG and IgA, anti-OmpC, anti-CBir1 and ANCA in 76 patients with AS alone, 77 patients with AS-IBD and 48 patients with MBP. Antibody positivity rates, median quantitative antibody levels and the proportion of patients with antibody levels in the 4^th quartile of a normal distribution were compared between the three groups of patients.

Results

Patients with AS alone demonstrated higher anti-CBir1 antibody positivity rates and median antibody levels than MBP patients. Anti-CBir1 positivity in AS was associated with elevation of acute phase reactants. AS-IBD patients demonstrated elevated responses when compared to AS alone for ASCA, anti-OmpC and anti-CBir1. Quartile analysis confirmed the findings.

Conclusions

These data suggest that adaptive immune responses to microbial antigens occur in AS patients without clinical IBD and support the theory of mucosal dysregulation as a mechanism underlying the pathophysiology of AS.     

基于ITS2高通量测序 研究强直性脊柱炎患者肠道真菌特征

目的探究强直性脊柱炎(ankylosing spondylitis,AS)患者肠道真菌菌群的多样性特征,分析健康人群与AS患者肠道真菌的结构差异。方法收集17例健康人群新鲜粪便样本和24例AS患者新鲜粪便样本,分别称为HC组和AS组,提取两组粪便样本总DNA;根据真菌ITS2区设计引物进行扩增,利用Illumina HiSeq PE250平台进行ITS2高通量测序;测序结果经过Reads拼接,OTUs(operational taxonomic units)聚类,Alpha和主成分分析,物种组成统计,显著性差异分析,最终得到样本物种信息。结果对肠道真菌菌群进行Alpha分析,各多样性指标中,shannon和observed_species指数差异有统计学意义(P0.05),其余指数差异均无统计学意义,故不能明确两组间多样性的差异。主成分分析提示差异显著。对肠道真菌结构进行分析,门的水平分析显示,担子菌门(Basidiomycota)在HC组和AS组中差异显著,接合菌门(Zygomycota)在两组间差异极显著;纲和属的水平分析显示,Ascomycota_unidentified纲在两组中差异显著,伞菌纲(Agaricomycetes)、Incertae_sedis_10纲、Orbiliomycetes纲差异极显著。Agaricomycetes_unidentified_1属、Amphinema属、Geoglossales_unidentified_1属、腔块菌属(Hydnotrya)差异显著,鹅膏菌属(Amanita)和锁瑚菌属(Clavulina)差异极显著。结论本实验证实了在AS患者中存在肠道真菌菌群失调,其特征是生物多样性和结构的改变,揭示肠道真菌也可能在AS发病中发挥作用。     

Prevalence of peripheral and extra-articular disease in ankylosing spondylitis versus non-radiographic axial spondyloarthritis: a meta-analysis

BackgroundPeripheral disease (arthritis, enthesitis and dactylitis) and extra-articular disease (uveitis, psoriasis and inflammatory bowel disease) is common in ankylosing spondylitis (AS) and non-radiographic axial spondyloarthritis (nr-axSpA). So far, however, summary data on the prevalence are lacking. The objective of this meta-analysis was to assess the prevalence of peripheral and extra-articular manifestations in ankylosing spondylitis (AS) and nr-axSpA.MethodsWe performed a systematic literature search to identify publications describing the prevalence of peripheral and extra-articular disease manifestations in patients with AS and nr-axSpA. We assessed the risk of bias and between-study heterogeneity, and extracted data. Pooled prevalence and prevalence differences were calculated.ResultsEight studies comprising 2236 patients with AS and 1242 with nr-axSpA were included: 7 of the studies were longitudinal cohort studies. There was male predominance in AS (70.4 %, 95 % CI 64.4, 76.0 %) but not in nr-axSpA (46.8 %, 95 % CI 41.7, 51.9), which was independent of the prevalence of human leukocyte antigen (HLA)-B27. The prevalence of HLA-B27 was similar in AS (78.0 % (95 % CI 73.9, 81.9 %) and nr-axSpA (77.4 %, 95 % CI 68.9, 84.9 %)). The pooled prevalence of arthritis (29.7 % (95 % CI 22.4, 37.4 %) versus 27.9 % (95 % CI 16.0, 41.6 %)), enthesitis (28.8 % (95 % CI 2.6, 64.8) versus 35.4 % (95 % CI 6.1, 71.2)). dactylitis (6.0 % (95 % CI 4.7, 7.5 %) versus 6.0 % (95 % CI 1.9, 12.0 %)), psoriasis (10.2 % (95 % CI 7.5, 13.2 %) versus 10.9 % (95 % CI 9.1, 13.0 %)) and inflammatory bowel disease (4.1 % (95 % CI 2.3, 6.5 %) versus 6.4 % (95 % CI 3.6, 9.7 %)) were similar in AS and nr-axSpA. The pooled prevalence of uveitis was higher in AS (23.0 % (95 % CI 19.2, 27.1 %)) than in nr-axSpA (15.9 % (95 % CI 11.8, 20.4 %)).ConclusionPeripheral and extra-articular manifestations are equally prevalent in AS and nr-axSpA, except for uveitis, which is slightly more prevalent in AS. These data provide evidence for the largely equal nature of disease manifestations in nr-axSpA and AS.

Electronic supplementary material

The online version of this article (doi:10.1186/s13075-016-1093-z) contains supplementary material, which is available to authorized users.     

Cystinotic and normal fibroblasts: Differential susceptibility to cysteine toxicity in vitro

Summary Extracellular cysteine concentrations between 0.5 and 2.5 mM resulted in death of normal but not cystinotic cells grown in Eagle's minimal essential medium containing supplemental fetal bovine serum and antibiotics. Differential cell survival was determined by viable cell counting using Trypan Blue dye exclusion. In cocultivation experiments of [³H]thymidine-labelled cystinotic fibroblasts with nonradioactive normal fibroblasts, autoradiography confirmed the selective survival of cystinotic cells in medium containing 1 mM cysteine. At this concentration of 1 mM cysteine, intracellular cystine content increased slightly in surviving normal cells but not in cystinotic cells, which normally contain a high level of intracellular cystine. This comparative resistance of cystinotic fibroblasts to elevated extracellular cysteine concentrations forms the basis for an in vitro selective system for these mutant human cells. Further exploration of this resistance phenomenon may well expand the understanding of the molecular defect in cystinotic cells.