Depression of Tissue-Type Plasminogen Activator and Enhancement of Urokinase-Type Plasminogen Activator as an Expression of Local Inflammation

Inflammatory processes are accompanied by extravascular deposition and breakdown of fibrin. We measured fibrinolytic parameters in synovial fluid (SF) and in plasma of 36 patients with rheumatoid arthritis (RA). As a control, SF of 13 patients with blunt knee trauma, and plasma of 17 healthy volunteers were studied. In RA patients, extravascular t-PA mediated plasminogen activation was depressed: mean SF tissue-type plasminogen activator (t-PA:Ag) concentration (2.1 ± 1.6 ng/ml) was four-fold lower, and plasminogen activator inhibitor (PAI) activity (284 ± 212%) four-fold higher than the plasma values of the same patients or of healthy donors. In contrast, u-PA related plasminogen activation was strongly enhanced: urokinase-type plasminogen activator (u-PA) antigen (23.1 ±12.4 ng/ml) was more than four-fold higher, single-chain u-PA (scu-PA) (5.3 ± 1.9 ng/ml) three-fold higher than in plasma of the same patients or of healthy donors, and active two-chain u-PA (tcu-PA) was detected in 14 of the 36 SF samples of RA patients. All of these changes in extravascular fibrinolytic parameters correspond with those induced by inflammatory mediators in cell cultures. In joint effusions of patients with a blunt knee trauma, the effects were intermediate: u-PA related parameters showed moderate changes in the same direction as in arthritis; t-PA antigen was also decreased. The only exception was that PAI was not increased. We conclude that the findings in traumatic effusions reflect transient effects as a reaction to trauma. In joint inflammation, the depressed t-PA mediated plasminogen activation, although more than compensated by the enhanced u-PA mediated plasminogen activation, results in protraction of fibrin removal. Besides, the enhanced u-PA activation might lead to proteolytic damage of the cartilage.

Proteasome inhibition and mechanism of resistance to a synthetic, library-based hexapeptide

Background The hexapeptide 4A6 (Ac-Thr(tBu)-His(Bzl)-Thr(Bzl)-Nle-Glu(OtBu)-Gly-Bza) was isolated from a peptide library constructed to identify peptide-based transport inhibitors of multidrug resistance (MDR) efflux pumps including P-glycoprotein and Multidrug Resistance-associated Protein 1. 4A6 proved to be a substrate but not an inhibitor of these MDR efflux transporters. In fact, 4A6 and related peptides displayed potent cytotoxic activity via an unknown mechanism. Objective To decipher the mode of cytotoxic activity of 4A6. Methods Screening of 4A6 activity was performed against the NCI60 panel of cancer cell lines. Possible interactions of 4A6 with the 26S proteasome were assessed via proteasome activity and affinity labeling, and cell growth inhibition studies with leukemic cells resistant to the proteasome inhibitor bortezomib (BTZ). Results The NCI60 panel COMPARE analysis revealed that 4A6 had an activity profile overlapping with BTZ. Consistently, 4A6 proved to be a selective and reversible inhibitor of β5 subunit (PSMB5)-associated chymotrypsin-like activity of the 26S proteasome. This conclusion is supported by several lines of evidence: (i) inhibition of chymotrypsin-like proteasome activity by 4A6 and related peptides correlated with their cell growth inhibition potencies; (ii) 4A6 reversibly inhibited functional β5 active site labeling with the affinity probe BodipyFL-Ahx₃L₃VS; and (iii) human myeloid THP1 cells with acquired BTZ resistance due to mutated PSMB5 were highly (up to 287-fold) cross-resistant to 4A6 and its related peptides. Conclusion 4A6 is a novel specific inhibitor of the β5 subunit-associated chymotrypsin-like proteasome activity. Further exploration of 4A6 as a lead compound for development as a novel proteasome-targeted drug is warranted.

One-year effects of glucocorticoids on bone density: a meta-analysis in cohorts on high and low-dose therapy

Background

Bone loss during glucocorticoid (GC) therapy is poorly quantified.

Objective

Quantification of bone loss in GC-treated patients with chronic inflammatory diseases (CID; low dose) and transplants (high dose).

Methods

Meta-analysis of cohorts: PubMed, Cochrane, EMBASE and bibliographic searches (1995–2012). Eligible studies prospectively included GC-treated patients with two dual X-ray absorptiometry measurements of spine or hip over a period of at least 12 months. Only supplementation with calcium or vitamin D3 was allowed. 5602 titles yielded 285 articles: 51 study arms in CID (N=1565), 18 study arms in transplantation (N=571). Prednisone-equivalent GC doses and inverse variance weighted mean bone changes were used in a random effects model.

Results

In CID, the mean GC dose was 8.7 mg/day (range 1.2–16.4). The mean 1-year bone loss in the lumbar spine was −1.7% (95% CI –2.2% to –1.2%); in the femoral neck: –1.3 (–1.8 to –0.7). In transplantation, the mean GC dose was 18.9 mg/day (range 6.0–52.7). Bone loss in the lumbar spine was −3.6% (–5.2% to –2.0%); in the femoral neck: –3.1% (–5.1% to –1.1%). Within the two groups, bone loss was not related to GC dose.

Conclusion

In CID, GC-related bone loss appears limited and manageable if current anti-osteoporotic strategies are fully implemented. In transplantation, and probably also other high-dose settings, bone loss is considerable and represents unmet need. The heterogeneity probably reflects the important influence of other factors, most notably the underlying disease and the efficacy of GC treatment.

Etanercept Increases Bone Mineral Density in Ankylosing Spondylitis, but Does Not Prevent Vertebral Fractures: Results of a Prospective Observational Cohort Study

OBJECTIVE

Ankylosing spondylitis (AS) is characterized by chronic inflammation leading to ankylosis, but also to low bone mineral density (BMD) and vertebral fractures (VFx). Treatment with tumor necrosis factor-α blockers decreases inflammation and has shown to be effective in increasing BMD. We studied the effects of etanercept (ETN) on BMD and VFx in patients with AS after 2 years of treatment. Further, we studied changes in bone turnover markers and radiological damage.

METHODS

Patients with active AS, treated with ETN for 2 years, were included. BMD lumbar spine and hip were measured at baseline and after 2 years, as well as radiological damage (modified Stoke Ankylosing Spondylitis Spinal Score with the addition of the thoracic spine), VFx (Genant method), and change in bone turnover markers.

RESULTS

Forty-nine patients with AS were included. After 2 years of ETN, hip BMD increased by 2.2% (p = 0.014) and lumbar spine BMD by 7.0% (p < 0.001). The Bath Ankylosing Spondylitis Disease Activity Index decreased significantly (p < 0.001), as well as C-reactive protein and erythrocyte sedimentation rate (p < 0.001). Despite ETN therapy, the number of patients with VFx more than doubled (from 6 to 15 patients, p = 0.003). Also, the radiological damage increased significantly over time (from 12.1 to 18.5, p < 0.001); however, no significant change in bone turnover markers was found.

CONCLUSION

This prospective longitudinal observational cohort study showed that after 2 years of ETN, BMD of the hip and spine increased significantly, but the number of patients with VFx and the severity of VFx increased as well. Besides that, radiological progression, including the thoracic spine, increased significantly. Thus, the favorable bone-preserving effect is accompanied by unfavorable outcomes on VFx and radiological damage.

Objective evaluation of physical functioning after tumor necrosis factor inhibitory therapy in patients with ankylosing spondylitis: a selection of 3 feasible performance-based tests

OBJECTIVE

(1) To select a limited number of performance-based tests that are reliable, show improvement in physical functioning after tumor necrosis factor inhibitor (TNFi) therapy in patients with ankylosing spondylitis (AS), and generate information equivalent to the full set of tests, and (2) are feasible for use in daily clinical practice.

METHODS

Eight performance-based tests were evaluated. To eliminate redundant testing, the tests that showed adequate reliability, the highest standardized response mean (SRM), and the largest proportion of patients with an improved performance-based physical functioning were selected. The selected tests were combined into a new criterion for improvement in physical functioning (AS Performance-based Improvement; ASPI). The number and percentage of improved patients identified with the ASPI and identified with the full set of performance tests were compared.

RESULTS

Reliability for all tests was adequate to excellent (ICC 0.73-0.96). The tests for bending, putting on socks, and getting up from the floor had the highest SRM (0.52-0.74) and showed the largest proportion of improved patients after TNFi therapy. The combination of these 3 tests was feasible in daily clinical practice and showed improved physical functioning after TNFi therapy in 67% of the patients.

CONCLUSION

The 3 selected tests are recommended for use in daily practice because they generate information comparable to the full set. They are reliable and feasible, and the combination of these tests showed improved physical functioning after TNFi therapy in 67% of the patients. Evaluation of physical functioning might be improved by adding these tests to other AS outcome measures.

Increased progression of carotid intima media thickness in thyroid peroxidase antibodies-positive rheumatoid arthritis patients

OBJECTIVE

Autoimmune diseases such as rheumatoid arthritis (RA) and hypothyroidism tend to cluster, and this coexistence amplifies the elevated cardiovascular risk in RA. Whether thyroid peroxidase antibodies (TPOabs) are associated with increased cardiovascular disease (CVD) risk has not been studied extensively. Therefore, this study determined firstly the prevalence of TPOabs in RA and secondly whether TPOabs were associated with CVD. Moreover, this study explored whether TPOabs were related to RA characteristics.

DESIGN AND METHODS

Data from the CARRÉ Study, an ongoing study investigating CVDs and its risk factors in RA (n=322), was used to ascertain the prevalence of TPOabs in RA patients. In addition, cardiovascular and RA disease characteristics were compared between TPOabs-positive and -negative patients at baseline and at a second visit after 3 years.

RESULTS

TPOabs were present in 47/322 (15%) RA patients and TSH levels were higher in TPOabs-positive patients (1.40 mU/l) compared with TPOabs-negative patients (1.26 mU/l, P=0.048). At baseline and after 3 years no association was observed between TPOabs and (risk factors for) CVD. Regression analyses revealed a significantly larger progression of carotid intima media thickness (cIMT; β=0.13 mm) in TPOabs-positive compared with TPOabs-negative patients independent of risk factors for cIMT progression. RA disease activity scores (DAS28) were higher in TPOabs-positive compared with TPOabs-negative patients (4.4 vs 3.8 P=0.018).

CONCLUSIONS

TPOabs were associated with increased cIMT progression. Moreover, an association between TPOabs and DAS28 was observed. Hence, TPOabs seems to have a role in the amplified cardiovascular risk in RA patients.

Imported Armillifer pentastomiasis: report of a symptomatic infection in The Netherlands and mini-review

We report a case of symptomatic visceral Armillifer pentastomiasis in a 23-year-old female Liberian immigrant to The Netherlands. The patient was referred to the gynecologist because of lower abdominal pain. During laparotomy, multiple adhesions were seen in the lower pelvis and a hydrosalpinx with an encapsulated Armillifer nymph, most likely Armillifer armillatus, was found. Key features of the parasite's cuticle which facilitate the diagnosis of pentastomiasis, are presented. Symptomatic pentastomiasis is uncommon, and most cases are diagnosed incidentally during surgery for other reasons, or at autopsy. With regard to increasing international migration, other imported pentastomiasis cases to Europe and North America are reviewed, and more cases are likely to be seen in the future.

Methotrexate analogues display enhanced inhibition of TNF-α production in whole blood from RA patients

OBJECTIVES

Although methotrexate (MTX) is the anchor drug in the treatment of rheumatoid arthritis (RA), patients experience clinical resistance to MTX upon prolonged treatment. We explored whether new-generation antifolates elicit superior anti-inflammatory properties when compared to MTX, based on their capacity to inhibit tumour necrosis factor (TNF)-α production.

METHOD

T cells in whole blood from 18 RA patients (including MTX-naïve, MTX- responsive, and MTX non-responsive patients) and seven healthy volunteers were stimulated with αCD3/αCD28 antibodies and incubated ex vivo for 72 h with MTX and eight novel antifolate drugs with potentially favourable biochemical and pharmacological properties. Drug concentrations exerting 50% inhibition (IC-50) of TNF-α production (by enzyme-linked immunosorbent assay, ELISA) were determined as an estimate for their anti-inflammatory capacity. In addition, induction of T-cell apoptosis was evaluated by flow cytometry.

RESULTS

The new-generation antifolates PT523, PT644, raltitrexed, and GW1843 proved to be potent inhibitors of TNF-α production in activated T cells from all three groups of RA patients and from healthy volunteers. Based on IC-50 values, these antifolates were up to 10.3 times more potent than MTX. The anti-inflammatory effects were observed at drug concentrations that provoked suppression of T-cell activation and induction of apoptosis in 20-40% of activated T cells.

CONCLUSION

In an ex-vivo setting, novel antifolates elicited marked inhibition of TNF-α production in activated T cells from RA patients. Further clinical evaluation is warranted to investigate whether a low dosage of these antifolates can elicit immunosuppressive effects equivalent to MTX, and whether they are superior to MTX in patients who fail to respond to MTX.

Six-year follow-up study of bone mineral density in patients with systemic lupus erythematosus

Long-term bone mineral density (BMD) changes and the associated factors in systemic lupus erythematosus (SLE) patients were assessed. Despite the remarkably low overall bone loss, significant spine bone loss was associated with the use of glucocorticoids, use of antimalarials, and lower 25-hydroxyvitamin D levels, stressing the importance of prevention of osteoporosis and vitamin D deficiency in SLE patients.

INTRODUCTION

The aim of this study is to assess the BMD changes in patients with SLE and to identify the associated factors.

METHODS

Demographic and clinical data of 126 SLE patients were collected, and BMD measurements of the lumbar spine and the total hip were performed by dual-energy X-ray absorptiometry at baseline and follow-up. Statistical analyses were performed using independent Mann-Whitney U tests and linear regression analyses.

RESULTS

At baseline, 39.7 % of the patients (90 % female, mean age 39 ± 12.2 years) had osteopenia, and 6.3 % had osteoporosis. The median follow-up duration was 6.7 years (range 1.9-9.3 years). Mean changes in BMD at the lumbar spine (-0.08 %/year) and the hip (-0.20 %/year) were not significant. During follow-up, 70 % of the patients used glucocorticoids. The mean ± SD daily glucocorticoid dose was 5.0 ± 5.0 mg. In multiple regression analysis, BMD loss at the spine was significantly associated with higher daily glucocorticoid dose and lower baseline 25-hydroxyvitamin D levels. BMD loss at the hip was associated with lower 25-hydroxyvitamin D levels at baseline, reduction of body mass index, and baseline use of antimalarials.

CONCLUSIONS

In this 6-year follow-up study, bone loss was remarkably low. A dose-dependent relationship between glucocorticoid use and spinal bone loss was found. In addition, the use of antimalarials and lower 25-hydroxyvitamin D levels at baseline were associated with BMD loss. These findings underline the importance of prevention and treatment of vitamin D deficiency and osteoporosis in SLE, especially in patients using glucocorticoids or antimalarials.

Risk of alanine transferase (ALT) elevation in patients with rheumatoid arthritis treated with methotrexate in a DAS-steered strategy

OBJECTIVE

To determine incidence of increased levels of alanine transferase (ALT) >2× upper limit of normal (ULN) in patients receiving methotrexate (MTX), treated according to a dynamic strategy, and to identify predictors of ALT of >2× ULN.

METHODS

Data of 508 recent-onset rheumatoid arthritis (RA) patients from the BeSt study, randomized to initial monotherapy or combination therapy, were used. Treatment was dynamic, aiming at a disease activity score = ≤ 2.4. ALT was measured every three months. With logistic regression analyses, baseline variables predictive of first ALT of >2× ULN were identified and the association between use of concomitant antirheumatic drugs, the actual and cumulative dose of MTX and ALT of >2× ULN was determined.

RESULTS

In total, 498 patients ever initiated MTX, with a total duration on MTX of 1,416 patient-years. In 89 patients, a first incidence of ALT of >2× ULN occurred. Incidence rate was 6.3 per 100 patient-years and cumulative incidence 18 %. ACPA positivity and baseline ALT of >1× ULN were independent predictors of later ALT of >2× ULN (OR 1.8 (95 % CI, 1.1-3.1) and OR 3.1 (95 % CI, 1.6-6.2), respectively). Smoking showed a trend (OR 1.6 (95 % CI, 0.98-2.7)). Mean MTX dosage over time was higher in patients with an ALT of >2× ULN. Patients who did not have an ALT of >2× ULN used more concomitant disease-modifying antirheumatic drugs and longer.

CONCLUSIONS

In RA patients treated with MTX according to a dynamic strategy resembling daily clinical practice, incidence of increased ALT of >2× ULN was lower than previously reported, and also without treatment adjustments, persistence was rare. The recommendations for ALT monitoring may be reevaluated.

Elevated liver enzymes in patients with ankylosing spondylitis treated with etanercept

TNF-alpha blocking agents are very effective in patients with ankylosing spondylitis (AS), but several cases of liver problems have been published. We systematically studied the frequency of this potential side effect in our AS patients treated with etanercept. Consecutive AS patients treated with etanercept for at least 3 months were included. Liver disease was defined as elevated liver enzymes more than 1.5 times the upper normal limit (UNL) and was categorised as probably, possibly, probably not or not related to etanercept treatment. Patients with and without raised liver enzymes were compared for prognostic factors. A total of 105 patients were included. Fifteen patients had elevated liver enzymes more than once. In nine cases, the liver disease was probably (five) or possibly (four) related to etanercept treatment. The liver enzyme elevations were serious (>3× UNL) in six cases and resulted in permanent cessation of etanercept in two cases. The nine patients with liver disease were compared with patients without elevated liver enzymes. No differences were found in age or use of alcohol; however, in patients with liver disease, a higher body mass index and a trend for a higher atherogenic index were observed. Hepatic steatosis was observed in five of six patients with elevated liver enzymes. Elevated serum aminotransferases, probably or possibly related to etanercept treatment, were observed in 9 % of the AS patients. An increased risk for the elevation of liver enzymes was found in patients with a higher body mass index. We recommend regular testing of liver enzymes in patients treated with etanercept.

High frequency of vertebral fractures in early spondylarthropathies

We demonstrated that vertebral fractures (VF) are commonly found in early SpA. Patients with VF had lower lumbar BMD than patients without VF. VF remained frequently 'unrecognized' and untreated. VF have been associated with more back pain, reduced Qol, and increased risk of future fractures which stresses the importance of recognition also in early stage SpA.

INTRODUCTION

VF are a common complication of long-standing ankylosing spondylitis (AS). However, data of VF in early AS patients and in other spondylarthropathies (SpA) are scarce. Therefore we examined the prevalence of VF in early SpA patients and investigated the associations between VF and demographic and disease-related variables.

METHODS

SpA patients were included consecutively and radiographs of the spine were made. VF were assessed according to the method of Genant et al.: fractures were defined as reduction of ≥20% of the vertebrae. Descriptive statistics, t-tests and logistic regression analyses were used to study the relationship between VF and demographic and disease-related variables, radiographic damage and BMD.

RESULTS

A total of 113 early SpA patients were included with a disease duration of 7 months, a mean age of 37 years. Seventeen patients (15%) had at least one VF. Fourteen patients had one VF, three patients had two VF. Most VF were located at Th6-Th8. In patients with VF, bone mineral density (BMD) of lumbar spine was lower than BMD of patients without VF (t-test: p = 0.043). Axial Psoriatic Arthritis (PsA) was significantly associated with a higher risk for VF (odds ratio [OR]: 4.62, 95% confidence interval [CI] 1.15-18.58, p = 0.031). No significant associations were found with disease activity variables nor with radiographic severity.

CONCLUSION

In a group of 113 early, young SpA patients, 15% already had at least one VF. Most VF were asymptomatic, undetected by routine diagnostic procedures and located at the mid-thoracic spine. The VF were associated with low BMD of the lumbar spine and with axial PsA.

Results of a questionnaire on the treatment of patients with Behçet's syndrome: a trend for more intensive treatment

OBJECTIVES

To determine the preferred treatment for patients with Behçet's syndrome.

METHODS

A questionnaire was given to all participants of the 2010 meeting of the International Society for Behçet's Disease.

RESULTS

Forty-one respondents from 6 different subspecialties. In the case of a patient with (severe) posterior uveitis or parenchymal central nervous system (CNS) disease no consensus was seen. A diffuse spectrum of different schedules were given. In both uveitis and CNS disease the majority of respondents preferred treatment options consisting of combination systemic therapy and systemic corticosteroids. TNF was preferred as first line drug in uveitis in 7.5% and in severe uveitis in 32.5% of respondents. In parenchymal CNS disease TNF blockage was given by 17% of the respondents. EULAR guidelines regarding uveitis were followed by 12/40 physicians. In patients with a new deep vein thrombosis, 90% of respondents would intensify immunosuppression. More than half would also anticoagulate.

CONCLUSIONS

Although consensus about how to treat patients with Behçet syndrome in different clinical situations is far from present, treatment has become more intensive when compared to 10-20 years ago. More uniformity should be sought for in the decision process in individual patients with Behçet's syndrome, regarding their treatment, as well as adhering to evidence, as presented in the EULAR guidelines, when present.

The interferon type I signature towards prediction of non-response to rituximab in rheumatoid arthritis patients

Introduction

B cell depletion therapy is efficacious in rheumatoid arthritis (RA) patients failing on tumor necrosis factor (TNF) blocking agents. However, approximately 40% to 50% of rituximab (RTX) treated RA patients have a poor response. We investigated whether baseline gene expression levels can discriminate between clinical non-responders and responders to RTX.

Methods

In 14 consecutive RA patients starting on RTX (test cohort), gene expression profiling on whole peripheral blood RNA was performed by Illumina^® HumanHT beadchip microarrays. Supervised cluster analysis was used to identify genes expressed differentially at baseline between responders and non-responders based on both a difference in 28 joints disease activity score (ΔDAS28 < 1.2) and European League against Rheumatism (EULAR) response criteria after six months RTX. Genes of interest were measured by quantitative real-time PCR and tested for their predictive value using receiver operating characteristics (ROC) curves in an independent validation cohort (n = 26).

Results

Genome-wide microarray analysis revealed a marked variation in the peripheral blood cells between RA patients before the start of RTX treatment. Here, we demonstrated that only a cluster consisting of interferon (IFN) type I network genes, represented by a set of IFN type I response genes (IRGs), that is, LY6E, HERC5, IFI44L, ISG15, MxA, MxB, EPSTI1 and RSAD2, was associated with ΔDAS28 and EULAR response outcome (P = 0.0074 and P = 0.0599, respectively). Based on the eight IRGs an IFN-score was calculated that reached an area under the curve (AUC) of 0.82 to separate non-responders from responders in an independent validation cohort of 26 patients using Receiver Operator Characteristics (ROC) curves analysis according to ΔDAS28 < 1.2 criteria. Advanced classifier analysis yielded a three IRG-set that reached an AUC of 87%. Comparable findings applied to EULAR non-response criteria.

Conclusions

This study demonstrates clinical utility for the use of baseline IRG expression levels as a predictive biomarker for non-response to RTX in RA.

Bone formation rather than inflammation reflects ankylosing spondylitis activity on PET-CT: a pilot study

Introduction

Positron Emission Tomography - Computer Tomography (PET-CT) is an interesting imaging technique to visualize Ankylosing Spondylitis (AS) activity using specific PET tracers. Previous studies have shown that the PET tracers [¹⁸F]FDG and [¹¹C](R)PK11195 can target inflammation (synovitis) in rheumatoid arthritis (RA) and may therefore be useful in AS. Another interesting tracer for AS is [¹⁸F]Fluoride, which targets bone formation. In a pilot setting, the potential of PET-CT in imaging AS activity was tested using different tracers, with Magnetic Resonance Imaging (MRI) and conventional radiographs as reference.

Methods

In a stepwise approach different PET tracers were investigated. First, whole body [¹⁸F]FDG and [¹¹C](R)PK11195 PET-CT scans were obtained of ten AS patients fulfilling the modified New York criteria. According to the BASDAI five of these patients had low and five had high disease activity. Secondly, an extra PET-CT scan using [¹⁸F]Fluoride was made of two additional AS patients with high disease activity. MRI scans of the total spine and sacroiliac joints were performed, and conventional radiographs of the total spine and sacroiliac joints were available for all patients. Scans and radiographs were visually scored by two observers blinded for clinical data.

Results

No increased [¹⁸F]FDG and [¹¹C](R)PK11195 uptake was noticed on PET-CT scans of the first 10 patients. In contrast, MRI demonstrated a total of five bone edema lesions in three out of 10 patients. In the two additional AS patients scanned with [¹⁸F]Fluoride PET-CT, [¹⁸F]Fluoride depicted 17 regions with increased uptake in both vertebral column and sacroiliac joints. In contrast, [¹⁸F]FDG depicted only three lesions, with an uptake of five times lower compared to [¹⁸F]Fluoride, and again no [¹¹C](R)PK11195 positive lesions were found. In these two patients, MRI detected nine lesions and six out of nine matched with the anatomical position of [¹⁸F]Fluoride uptake. Conventional radiographs showed structural bony changes in 11 out of 17 [¹⁸F]Fluoride PET positive lesions.

Conclusions

Our PET-CT data suggest that AS activity is reflected by bone activity (formation) rather than inflammation. The results also show the potential value of PET-CT for imaging AS activity using the bone tracer [¹⁸F]Fluoride. In contrast to active RA, inflammation tracers [¹⁸F]FDG and [¹¹C](R)PK11195 appeared to be less useful for AS imaging.

Inactivating PSMB5 mutations and P-glycoprotein (multidrug resistance-associated protein/ATP-binding cassette B1) mediate resistance to proteasome inhibitors: ex vivo efficacy of (immuno)proteasome inhibitors in mononuclear blood cells from patients with rheumatoid arthritis

Bortezomib (BTZ), a registered proteasome inhibitor (PI) for multiple myeloma, has also been proposed as a potential antirheumatic agent. Its reported side effects, however, make it unappealing for long-term administration, and resistance may also develop. To overcome this, second-generation PIs became available. Here, we investigated whether a novel class of peptide epoxyketone-based PIs, including carfilzomib, N-((S)-3-methoxy-1-(((S)-3-methoxy-1-(((S)-1-((R)-2-methyloxiran-2-yl)-1-oxo-3-phenylpropan-2-yl)amino)-1-oxopropan-2-yl)amino)-1-oxopropan-2-yl)-2-methylthiazole-5-carboxamide (ONX0912), and (S)-3-(4-methoxyphenyl)-N-((S)-1-((S)-2-methyloxiran-2-yl)-1-oxo-3-phenylpropan-2-yl)-2-((S)-2-(2-morpholinoacetamido)propanamido)propanamide (ONX0914), might escape two established BTZ-resistance mechanisms: 1) mutations in the proteasome β5 subunit (PSMB5) targeted by these PIs, and 2) drug efflux mediated by ATP-binding cassette transporters. THP1 myeloid sublines with acquired resistance to BTZ (54- to 235-fold) caused by mutations in the PSMB5 gene displayed marked cross-resistance but less pronounced cross-resistance to carfilzomib (9- to 32-fold), ONX0912 (39- to 62-fold), and ONX0914 (27- to 97-fold). As for ATP-binding cassette transporter-mediated efflux, lymphoid CEM/VLB cells with P-glycoprotein (Pgp)/multidrug resistance 1 overexpression exhibited substantial resistance to carfilzomib (114-fold), ONX0912 (23-fold), and ONX0914 (162-fold), whereas less resistance to BTZ (4.5-fold) was observed. Consistently, β5 subunit-associated chymotrypsin-like proteasome activity was significantly less inhibited in these CEM/VLB cells. Ex vivo analysis of peripheral blood mononuclear cells from therapy-naive patients with rheumatoid arthritis revealed that, although basal Pgp levels were low, P-glycoprotein expression compromised the inhibitory effect of carfilzomib and ONX0914. However, the use of P121 (reversin 121), a Pgp transport inhibitor, restored parental cell inhibitory levels in both CEM/VLB cells and peripheral blood mononuclear cells. These results indicate that the pharmacologic activity of these PIs may be hindered by drug resistance mechanisms involving PSMB5 mutations and PI extrusion via Pgp.

Moving instead of asking? Performance-based tests and BASFI-questionnaire measure different aspects of physical function in ankylosing spondylitis

Introduction

Ankylosing Spondylitis (AS) is characterised by limitations in physical function. The Bath Ankylosing Spondylitis Functional Index (BASFI) is considered to be the gold-standard to assess physical function in AS patients. However, the BASFI questionnaire is a self-reported outcome measure and susceptible to subjective interpretation (under- or over-estimation). More objective outcome measures, like performance-based tests, could provide an objective outcome measurement for the evaluation of limitations in physical function. Therefore, the primary aim of this study was to determine the association between performance-based measures and the BASFI questionnaire.

Methods

In this cross-sectional study 126 AS patients completed the BASFI questionnaire and eight performance-based tests based on BASFI-items. Each test received three scores: one for performance (time or points) and a score for exertion and pain experienced during performance (using modified Borg-scale and VAS 0-100 mm, respectively). Linear regression analyses were used to assess the associations between the BASFI questionnaire and performance-based tests.

Results

The univariable association between performance and BASFI-score was moderate with a R-square of 0.31 and Beta of 0.56 (p's < 0.05). In a multivariable analysis, the association between performance, exertion and pain on the one hand and BASFI-score on the other was assessed; R-square increased to 0.54: the Beta's for exertion and pain during performance were 0.38 and 0.26, respectively; the Beta for performance decreased to 0.19 (p's < 0.05).

Conclusions

This study demonstrates that alongside actual performance, patients seem to incorporate exertion and pain in their assessment of perceived physical function on the BASFI questionnaire. Performance-based tests could provide an objective outcome measurement for the evaluation of physical function and give relevant new information in addition to the BASFI questionnaire.

Macrophage positron emission tomography imaging as a biomarker for preclinical rheumatoid arthritis: findings of a prospective pilot study

OBJECTIVE

To conduct a prospective pilot study to determine whether macrophage targeting by 11C-(R)-PK11195 positron emission tomography (PET) can visualize subclinical synovitis in arthralgia patients who have anti-citrullinated protein antibodies (ACPAs).

METHODS

Twenty-nine arthralgia patients who were positive for ACPAs but did not have clinical arthritis were studied. High (spatial)-resolution 11C-(R)-PK11195 PET scans of the hands and wrists were performed. For all metacarpophalangeal, proximal interphalangeal, and wrist joints (i.e., 22 joints per patient), tracer uptake was scored semiquantitatively (0-3 scale) by 2 observers who were blinded with regard to the clinical data. Patients were followed up prospectively for 24 months to investigate the development of clinical arthritis.

RESULTS

Overall agreement and kappa values for the readings of the 2 observers were, respectively, 97% and 0.91 (95% confidence interval [95% CI] 0.74-1) at the patient level and 99% and 0.81 (95% CI 0.65-0.96) at the joint level. In 4 patients, at least 1 and as many as 5 PET-positive joints (score≥1) were found at baseline. Within 2 years of followup, 9 patients had developed clinical arthritis. This included all 4 patients with positive findings on the 11C-(R)-PK11195 scan, who developed clinical arthritis in the hand/wrist region, as identified on PET scans. Of the 5 remaining arthritis patients with negative findings on PET scans, 2 developed arthritis in the hand joints and 3 developed arthritis at locations outside the field of view of the PET scanner.

CONCLUSION

Subclinical arthritis in ACPA-positive arthralgia patients could be visualized by 11C-(R)-PK11195 PET scanning and was associated with development of arthritis within 2 years of followup. This indicates that 11C-(R)-PK11195 PET may be useful in determining arthritis activity in the preclinical phase of RA.

Changes in hand bone mineral density and the association with the level of disease activity in patients with rheumatoid arthritis: bone mineral density measurements in a multicenter randomized clinical trial

OBJECTIVE

To determine if metacarpal bone mineral density (mBMD) gain occurs in patients with rheumatoid arthritis (RA). If mBMD loss is driven by inflammation, we expect to find mBMD gain in patients who are in remission.

METHODS

mBMD was measured by digital x-ray radiogrammetry in consecutive radiographs of 145 patients with RA with either continuous high disease activity (HDA; Disease Activity Score [DAS] >2.4), low disease activity (LDA; 1.6 ≥ DAS ≤ 2.4), or continuous clinical remission (CR; DAS <1.6) during a 1-year observation period. The association of mBMD changes with disease activity was investigated with multinomial regression analysis. Next, clinical variables associated with mBMD gain were identified.

RESULTS

Mean change in mBMD in CR patients was -0.03%, compared to -3.13% and -2.03% in HDA and LDA patients, respectively (overall, P < 0.001). Of the patients in CR, 32% had mBMD loss (less than or equal to -4.6 mg/cm2/year), compared to 62% and 66% of the patients with HDA or LDA, respectively, whereas 26% of the patients in CR had mBMD gain (≥4.6 mg/cm2/year), compared to 2% of the patients with HDA and 5% of the patients with LDA. Patients in CR had a higher chance of having mBMD gain, compared with LDA and HDA (relative risk [RR] 14.9, 95% confidence interval [95% CI] 3.0-18.7 and RR 4.7, 95% CI 1.2-6.3, respectively). CR, hormone replacement therapy, and lower age were significant independent predictors of mBMD gain.

CONCLUSION

In RA, mBMD gain occurs primarily in patients in continuous (≥1 year) CR and rarely in patients with continuous HDA or LDA. This suggests that mBMD loss is driven by inflammation.