Abstract Graeme Kohler BSc. (Health Education), MA (Health Promotion) School of Health and Human Performance, Dalhousie University Objective: To understand the experiences of young men living with Ankylosing Spondylitis (AS). Methods: Using an interpretive phenomenological research approach, two semi-structured interviews were conducted with 7 male informants ranging from ages 22 – 37. All of the informants lived in Nova Scotia and had been diagnosed with AS for at least one year. Thematic analysis was used to analyze the data. Results & Conclusions: Informants displayed a strong affinity to hegemonic masculine behaviours. The overriding theme was I’m a Man. The four emerging themes were: Trying to maintain normalcy, Do what I like to do, I have to work, and I don’t really ask for support. Several barriers to support and health care access were identified that have implications for health promotion, the men themselves, and various AS care providers.

A consecutive series of 280 Charnley low-friction arthroplasties, performed between 1966 and 1978, on 192 patients, who were less than 40 years of age at the time of operation, were followed up for an average duration of 20.1 years. Patients were divided into four groups based on underlying disease process, and only three patients (5 hips) could not be traced. Patients with rheumatoid arthritis had significantly lower rates of acetabular component loosening, migration and revision (all p< 0.05), and patients with developmental dysplasia of the hip had the highest rates as well as a significantly higher rate of combined clinical and radiological component failure (p < 0.05). Patients with degenerative arthrosis had the highest rates of femoral implant loosening, revision and failure (all p < 0.05), and patients with ankylosing spondylitis and rheumatoid arthritis had the lowest. Age (< 30 years or 30 to 40 years at operation), gender, heterotopic ossification, hypertrophy of the femoral cortex at the tip of the prosthesis or development of changes in the medial femoral calcar were not associated with an increased risk of component failure or revision (all p > 0.05). The average annual rate of wear of revised components, in each of the four groups and the series as a whole, was significantly higher than the rate in surviving original components (p < 0.04), and the development of osteolysis, and increasing wear of the acetabular component were associated with failure and revision of both the acetabular and femoral components (both p < 0.01). Cox regression analysis confirmed that increasing average annual acetabular wear was the most significant factor determining the outcome of the arthroplasty (p < 0.001). For each additional millimetre of wear observed, the risk of component failure or revision in any one year increased significantly (p < 0.02). The 25-year survivorship of implants with an average acetabular wear rate of less than 0.1 mm/yr (117 arthroplasties) was greater than 90% but no arthroplasties with a rate in excess of 0.2 mm/yr survived 25 years, and only 40% survived 20 years.

HLA-B27 and ERAP1 are the two strongest predisposing genetic factors to Ankylosing Spondylitis (AS). As a key aminopeptidase in MHC class I presentation, ERAP1 potentially contributes to AS pathogenesis through altering HLA-B27 peptide presentation. In this thesis, I first studied the effect of AS-associated ERAP1 variation on its enzyme activity in vitro. Trimming of two N-terminally extended HLA-B27 epitopes was decreased by K528R mutation; the effect of R725Q was however substrate-dependent. I also investigated the effects of ERAP1 silencing on the repertoire of peptides bound to HLA-B27 and on peptide presentation to Cytotoxic T lymphocytes (CTLs). In both HeLa.B27 and C1R.B27 cells, the proportion of 9mer peptides, the canonical MHC class I peptide length, was decreased by ERAP1 silencing whereas the percentage of longer peptides (11-13mer) was increased. Surprisingly, following ERAP1 silencing, C-terminally extended versions of 9mer and 10mer peptides were readily identified. In both HeLa.B27 and mouse fibroblasts expressing HLA-B27, ERAP1 silencing/knockout reduced recognition by KK10-specific HLA-B27-restricted CTLs following recombinant vaccinia viral infection or transfection with minigenes expressing KK10 precursors. Interestingly, KK10 CTL recognition following extended KK10 minigene transfection was reduced in the presence of the AS protective variant, K528R-ERAP1 compared to wildtype ERAP1. The effects of ERAP1 inhibition (Leucinethiol), silencing (siRNA & shRNA) and introduction in ERAAP-/- cells on cell surface HLA-B27 expression were also studied. My finding validates the role of ERAP1 and HLA-B27 interaction in AS pathogenesis indicated by GWAS. ERAP1 inhibition could potentially be used for treatment in AS and other ERAP1-associated diseases.

Possession of the Major Histocompatibility Complex (MHC) allele, HLA-B27 (B27), strongly predisposes to the development of spondyloarthritis. Furthermore, B27 exists as polymorphic variants, with some subtypes (such as B*2705) being more strongly associated with disease than others (B*2709). The immunological function of MHC molecules is to present peptides in a heterotrimeric complex with beta-2-microglobulin (β2m); however, B27 has also been observed to form non-classical (β₂m –free) homodimers at the cell surface. It has been suggested that there may be a pathogenic role for cell surface B27 homodimer interactions with Natural Killer (NK) cell receptors, such as Leukocyte Immunoglobulin like Receptors (LILRs). In this thesis I characterise these interactions and investigate molecular differences between two B27 subtypes. Here I show that the B*2705 subtype forms homodimers more readily than the B*2709 subtype, but once formed, B27 homodimers of the 2 different subtypes exhibit comparable binding specificities and affinities to the NK receptors. On the other hand, I show significant differences in the binding specificities and affinities of these receptors to B27 homodimers and heterotrimers. LILRB1 does not bind B27 homodimers, but does bind B27 heterotrimers. LILRB2 binds B27 heterotrimers with a KD of 22μM, whereas LILRB2 binds B27 homodimers more strongly with a KD of 2.5μM. In addition to these main findings, I have characterised the specificity and affinity of candidate B27 homodimer-specific antibodies. I have performed epitope-mapping experiments and developed a model for binding to the B27 homodimer. Finally, I have identified crystallisation conditions for the B27 homodimer in complex with a Fab, allowing for X-ray crystallography studies. In this thesis, I have characterised for the first time the molecular interactions of the B27 homodimer with NK cell ligands and show that they are different from those with the B27 heterotrimer. This work supports a hypothesis of B27 homodimer induced pathology involving NK receptors.

The first objective of my work was to use the ank/ank (progressive ankylosis) mutant mice, which have a deficiency in inorganic pyrophosphate transport, to address the role of Ank in joint ankylosis. I observed the presence of hypertrophic chondrocytes in the uncalcified ank/ank mice articular cartilage. This novel phenotype is likely due to a dysregulation of chondrocyte maturation as these chondrocytes expressed hypertrophic chondrocyte markers (collagen type X and tissue non-specific alkaline phosphatase). I also showed by immunohistochemical staining that beta-catenin expression was upregulated and localized in the nuclei of articular ank/ank chondrocytes, suggesting activation of Wnt/beta-catenin signaling in these chondrocytes. The second objective was to use ank/ank mice as an informative model for understanding ankylosis mechanisms in human ankylosing spondylitis (AS) patients, as WNT/beta-catenin signaling plays an important role in ankylosis in AS patients. We attempted rescue of joint ankylosis in ank/ank mice by gene transfer of noggin, an antagonist of BMP signaling. Paradoxically, noggin-treated ank/ank mice had accelerated ankylosis, as evidenced by joint pathology and IHC staining of beta-catenin showed more intense signals in the spinal chondrocytes of the treated mice. As noggin and sclerostin (an antagonist of beta-catenin signaling) form a mutually inhibitory complex, we hypothesize that the formation of this complex results in relieving suppression of both beta-catenin and BMP signaling, leading to more severe ankylosis in ank/ank mice. By quantitative molecular imaging, I have demonstrated that ankylosis in these mutant mice developed simultaneously in distal and axial joint, instead of being a centripetal process. In summary, I have made three original observations in the ank/ank mice: the hypertrophic chondrocyte phenotype; activation of beta-catenin signaling and the simultaneous development of ankylosis in distal and axial joints. These mutant mice serve as valuable model for pre-clinical studies which enable modeling and testing of novel anti-ankylosis treatments.

The first objective of my work was to use the ank/ank (progressive ankylosis) mutant mice, which have a deficiency in inorganic pyrophosphate transport, to address the role of Ank in joint ankylosis. I observed the presence of hypertrophic chondrocytes in the uncalcified ank/ank mice articular cartilage. This novel phenotype is likely due to a dysregulation of chondrocyte maturation as these chondrocytes expressed hypertrophic chondrocyte markers (collagen type X and tissue non-specific alkaline phosphatase). I also showed by immunohistochemical staining that beta-catenin expression was upregulated and localized in the nuclei of articular ank/ank chondrocytes, suggesting activation of Wnt/beta-catenin signaling in these chondrocytes. The second objective was to use ank/ank mice as an informative model for understanding ankylosis mechanisms in human ankylosing spondylitis (AS) patients, as WNT/beta-catenin signaling plays an important role in ankylosis in AS patients. We attempted rescue of joint ankylosis in ank/ank mice by gene transfer of noggin, an antagonist of BMP signaling. Paradoxically, noggin-treated ank/ank mice had accelerated ankylosis, as evidenced by joint pathology and IHC staining of beta-catenin showed more intense signals in the spinal chondrocytes of the treated mice. As noggin and sclerostin (an antagonist of beta-catenin signaling) form a mutually inhibitory complex, we hypothesize that the formation of this complex results in relieving suppression of both beta-catenin and BMP signaling, leading to more severe ankylosis in ank/ank mice. By quantitative molecular imaging, I have demonstrated that ankylosis in these mutant mice developed simultaneously in distal and axial joint, instead of being a centripetal process. In summary, I have made three original observations in the ank/ank mice: the hypertrophic chondrocyte phenotype; activation of beta-catenin signaling and the simultaneous development of ankylosis in distal and axial joints. These mutant mice serve as valuable model for pre-clinical studies which enable modeling and testing of novel anti-ankylosis treatments.

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The aim of this thesis was to examine the role of diet in ankylosing spondylitis (AS). Patients were examined in: i) a postal questionnaire survey of dietary habits and gastrointestinal (GI) symptoms; ii) a study on biomarkers of diet and disease activity; iii) a comparison of cardiovascular risk factors with the general population using data from the Västerbotten Intervention Programme (VIP), and; iv) a 21-week omega-3 fatty acid supplementation study regarding the effects on disease activity. The postal survey (111 respondents) revealed no correlation between dietary habits and disease activity measured by the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI). However, GI problems, and in particular GI pain, were prevalent in patients with AS irrespective of NSAID usage.Gastrointestinal pain was predicted by higher BASDAI and a higher consumption of vegetables. Overall, 30 (27%) of the patients experienced an aggravation of gastric symptoms when consuming certain foods. In the study of biomarkers (n=66) no correlation was found between diet and disease activity as assessed by BASDAI. There were, however, positive correlations between BASDAI and the content of arachidonic acid (AA) in plasma phospholipids (rs=0.39, p&lt;0.01) and the estimated activity of the enzyme delta-5-desaturase (rs=0.37, p&lt;0.01). This may reflect a process involved in the inflammation associated with AS that requires further investigation. Comparing data from the VIP for patients (n=89) and controls showed no significant differences regarding diet, physical activity or smoking. Nonetheless, more pronounced correlations between blood lipids and diet were identified among patients than in controls. Furthermore, the levels of cholesterol and triglycerides were lower in patients compared with controls. Lastly, in the supplementation study, a high-dose of long-chain omega-3 fatty acids (4.55 grams/day) was found to lower disease activity, as measured by BASDAI, whereas low-dose treatment (1.95 grams/day) caused no change. In conclusion, within a group of Swedish AS patients we found no correlation between ordinary dietary habits and disease activity. Diet in western populations of patients with AS may, however, be of importance for gastric symptoms and for cardiovascular risk factors. The finding of a lowered disease activity in patients on high-dose supplementation with long-chain omega-3 fatty acids indicates that a radical dietary shift may influence disease activity. The findings of a positive correlation between disease activity and plasma AA, and the decreased levels of blood lipids imply the need for further studies into fatty acid metabolism in AS.

BACKGROUND: The Spondyloarthritis Research and Treatment Network (SPARTAN), together with the American College of Rheumatology (ACR) and the Spondylitis Association of America (SAA), published treatment recommendations for ankylosing spondylitis (AS) and non-radiographic axial spondyloarthritis (nr-axSpA) in 2016. The extent to which these recommendations are being followed in clinical practice is unclear. We performed a retrospective chart review focusing on disease activity monitoring, back exercises and DXA scanning in adults with AS. METHODS: We reviewed electronic medical records at a single academic hospital network. The cohort for this study was derived from an existing population of 775 patients identified as having AS or nr-axSpA based on imaging studies, all of whom had 3 or more ICD- 9 or 10 codes for AS (720.x or M45.x). Patients were included if they had at least one rheumatology clinic visit for AS during a three-year study period from July 1, 2016 to June 30, 2019. Data were recorded for the first and last clinic visit within the study period. RESULTS: 358 patients met inclusion criteria. The study population was predominantly male (72.6%) with a mean age of 48.1 years (SD=15.5 years); 84.9% had AS based on review of pelvic or spine radiographs. A total of 661 clinic visits were analyzed. A clinical disease activity measure was recorded at 110/661 (16.6%) visits. RAPID3 was the most frequently used score (57.3%) followed by BASDAI (33.6%) and ASDAS (9.1%). CRP and/or ESR was ordered at 346/661 (52.3%) visits. AS-specific physical therapy (PT) or home exercises for the back were documented in 103/661 (15.6%) visits. A discussion of general exercise unrelated to the back was documented in an additional 153/661 (23.1%) visits. 303/358 patients had two or more visits during the study period. The use of disease activity measures or documentation of AS-specific PT or home exercises did not increase between the first and last visit. 65/358 (18.2%) patients had a DXA scan at any time prior to June 30, 2019. Patients with a DXA were significantly older than those without (58.7 vs. 45.7 years, p<0.001) and more likely to be female (31.6% vs. 13.1%, p<0.0001). 32/358 (8.9%) patients carried a diagnosis of osteoporosis, while 27/358 (7.5%) patients had a history of vertebral fracture. 48.1% of patients with a history of vertebral fracture had a DXA compared to 15.7% of patients without vertebral fracture (p<0.001). CONCLUSION: Monitoring with validated disease activity measures, treatment with AS- specific PT or home exercises, and osteoporosis screening with DXA were performed at low frequencies in our study population. Our data emphasize the need for more education of rheumatologists and the development of implementation strategies along with future updates of the AS/nr-axSpA treatment recommendations. / 2020-12-07T00:00:00Z

Ankylosing spondylitis (AS) is a chronic, inflammatory rheumatic disease that has a highly variable disease course. Three biologic agents, adalimumab, etanercept, and infliximab, have been developed for the treatment of AS. We conducted three studies: 1) an exploratory analysis of a year-long longitudinal dataset to gain insight into the variability of disease activity, physical function, and well-being and to explore the relationship between these outcome measures; 2) a systematic review of the available evidence for the efficacy of biologic treatment; 3) a systematic review of potential adverse effects of this treatment. We found that repeated measures of disease activity, function and well-being fluctuate considerably between patients, with complex patterns occurring over time within patients. There was mostly high quality evidence that these biologics are efficacious against placebo. We did not find evidence of an increase in serious adverse events or serious infections from short-term randomized controlled trials.