Genetic absence of the urokinase-type plasminogen activator (uPA) reduces arthritis progression in the collagen-induced arthritis (CIA) mouse model to an extent just shy of disease abrogation, but this remarkable observation has not been translated into therapeutic intervention. Our aim was to test the potential in mice of an Ab that blocks the proteolytic capacity of uPA in the CIA model and the delayed-type hypersensitivity arthritis model. A second aim was to determine the cellular origins of uPA and the uPA receptor (uPAR) in joint tissue from patients with rheumatoid arthritis. A mAb that neutralizes mouse uPA significantly reduced arthritis progression in the CIA and delayed-type hypersensitivity arthritis models. In the CIA model, the impact of anti-uPA treatment was on par with the effect of blocking TNF-α by etanercept. A pharmacokinetics evaluation of the therapeutic Ab revealed target-mediated drug disposition consistent with a high turnover of endogenous uPA. The cellular expression patterns of uPA and uPAR were characterized by double immunofluorescence in the inflamed synovium from patients with rheumatoid arthritis and compared with synovium from healthy donors. The arthritic synovium showed expression of uPA and uPAR in neutrophils, macrophages, and a fraction of endothelial cells, whereas there was little or no expression in synovium from healthy donors. The data from animal models and human material provide preclinical proof-of-principle that validates uPA as a novel therapeutic target in rheumatic diseases.

Knee osteoarthritis (KOA) is one of the most common causes of physical disability in the elderly population. With an increasing ageing and obese population, the prevalence of KOA is expected to rise substantially. The needs for a better understanding of the disease and tools that can predict the course of the disease, for example following treatment, are therefore imperative. 

Inflammation has over the last years been recognised as an important factor for both the symptomatology and disease course in KOA. Synovitis, inflammation of the synovium, is the hallmark of intra-articular inflammation and has been associated with pain, symptoms and disease progression. Synovitis can be visualised on conventional static MRI. However, the addition of a dynamic contrast-enhanced (DCE) MRI-sequence enables the assessment of the synovium both in regards of its morphology and perfusion. Studies in both KOA and rheumatoid arthritis have shown that DCE-MRI measures of synovitis are more sensitive than conventional static MRI in regards of microscopic synovitis and patient-reported outcome measures (PROMs).

 The aims of this PhD project were to characterise synovitis in KOA with conventional static and DCE MRI in regards of histology (study I), its association with PROMs (studies II-III) and changes following a symptoms-improving intervention (study III). We found that DCE-MRI-measures of synovitis seem to be superior to conventional static MRI in their association with histological synovitis (study I) and pain (study II) in a cross-sectional setting. However, the use of DCE-MRI over conventional static CE-MRI cannot be justified when assessing the long-term changes in synovitis following an intervention with intra-articular corticosteroids/placebo and exercise (study III). 

Evidence is mounting that KOA is constituted of different phenotypes. There is an urgent need to define these in order to improve and individualise treatment and management. It is essential to gain a better understanding of the different pro-cesses taking place in KOA, on an individual level and in the different stages of the disease. DCE-MRI may very well be a useful tool in facing these challenges especially in regards of the role of perfusion and inflammation in KOA and osteoarthri-tis in general.

OBJECTIVE: To estimate the impact of NICE approval of tumor necrosis factor inhibitor (TNFi) therapies on the incidence of total hip replacement (THR) and total knee replacement (TKR) among rheumatoid arthritis (RA) patients in England and Wales.

METHODS: Primary care data [Clinical Practice Research Datalink (CPRD)] for the study period (1995-2014) were used to identify incident adult RA patients. The age and sex-standardised 5-year incidence of THR and TKR was calculated separately for RA patients diagnosed in each six-months between 1995-2009. We took a natural experimental approach, using segmented linear regression to estimate changes in level and trend following the publication of NICE TA 36 in March 2002, incorporating a 1-year lag. Regression coefficients were used to calculate average change in rates, adjusted for prior level and trend.

RESULTS: We identified 17,505 incident RA patients of whom 465 and 650 underwent THR and TKR surgery, respectively. The modeled average incidence of THR and TKR over the biologic-era was 6.57/1000 person years (PYs) and 8.51/1000 PYs, respectively, with projected (had pre-NICE TA 36 level and trend continued uninterrupted) figures of 5.63/1000 PYs and 12.92 PYs, respectively. NICE guidance was associated with a significant average decrease in TKR incidence of -4.41/1000 PYs (95% C.I. -6.88 to -1.94), equating to a relative 34% reduction. Overall, no effect was seen on THR rates.

CONCLUSIONS: Among incident RA patients in England and Wales, NICE guidance on TNFi therapies for RA management was temporally associated with reduced rates of TKR but not THR.

OBJECTIVE: Compare arthroscopic partial meniscectomy to a true sham intervention.

METHODS: Sham-controlled superiority trial performed in three county hospitals in Denmark comparing arthroscopic partial meniscectomy to skin incisions only in patients aged 35-55 years with persistent knee pain and an MRI-confirmed medial meniscus lesion. A computer-generated table of random numbers generated two comparison groups. Participants and outcome assessors were blinded to group allocation. Exclusions were locking knees, high-energy trauma or severe osteoarthritis. Outcomes were collected at baseline, 3 and 24 months. We hypothesised no difference between groups. The primary outcome was the between-group difference in change from baseline to 2 years in the mean score across all five normalised Knee injury and Osteoarthritis Outcome Score (KOOS) subscales (KOOS5).

RESULTS: Forty-four patients (of the estimated 72) underwent randomisation; 22 in each group. Sixteen participants (36%) were non-blinded and eight participants (36%) from the sham group crossed over to the surgery group prior to the 2-year follow-up. At 2 years, both groups reported clinically relevant improvements (surgery 21.8, skin incisions only 13.6), the mean difference between groups was 8.2 in favour of surgery, which is slightly less than the cut-off of 10 prespecified to represent a clinically relevant difference; judged by the 95% CI (-3.4 to 19.8), a possibility of clinically relevant difference could not be excluded. In total, nine participants experienced 11 adverse events; six in the surgery group and three in the skin-incisions-only group.

CONCLUSION: We found greater improvement from arthroscopic partial meniscectomy compared with skin incisions only at 2 years, with the statistical uncertainty of the between-group difference including what could be considered clinically relevant. Because of the study being underpowered, nearly half in the sham group being non-blinded and one-third crossing over to surgery, the results cannot be generalised to the greater patient population.

TRIAL REGISTRATION NUMBER: NCT01264991.

OBJECTIVES: Large-scale observational cohorts may be used to study the effectiveness and rare side effects of biological disease-modifying anti-rheumatic drugs (bDMARDs) in ankylosing spondylitis (AS), but may be hampered by differences in baseline characteristics and disease activity across countries. We aimed to explore the research infrastructure in the five Nordic countries regarding bDMARD treatment in AS.

METHOD: This observational cohort study was based on data from biological registries in Denmark (DANBIO), Sweden (SRQ/ARTIS), Finland (ROB-FIN), Norway (NOR-DMARD), and Iceland (ICEBIO). Data were collected for the years 2010-2016. Registry coverage, registry inventory (patient characteristics, disease activity measures), and national guidelines for bDMARD prescription in AS were described per country. Incident (first line) and prevalent bDMARD use per capita, country, and year were calculated. In AS patients who started first line bDMARDs during 2010-2016 (n = 4392), baseline characteristics and disease activity measures were retrieved.

RESULTS: Registry coverage of bDMARD-treated patients ranged from 60% to 95%. All registries included extensive prospectively collected data at patient level. Guidelines regarding choice of first line drug and prescription patterns varied across countries. During the period 2010-2016 prevalent bDMARD use increased (p < 0.001), whereas incident use tended to decrease (p for trend < 0.004), with large national variations (e.g. 2016 incidence: Iceland 10.7/100 000, Finland 1.7/100 000). Baseline characteristics were similar regarding C-reactive protein, but differed for other variables, including the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) (range 3.5-6.3) and Ankylosing Spondylitis Disease Activity Score (ASDAS) (2.7-3.8) (both p < 0.0001).

CONCLUSION: Collaboration across the five Nordic biological registries regarding bDMARD use in AS is feasible but national differences in coverage, prescription patterns, and patient characteristics must be taken into account depending on the scientific question.