Artur J. de Brum-Fernandes

Anti-Sa antibodies and antibodies against cyclic citrullinated peptide are not equivalent as predictors of severe outcomes in patients with recent-onset polyarthritis

The prognostic value of two antibodies targeting citrullinated antigens, anti-Sa and anti-cyclic citrullinated peptide (CCP), present at inclusion, was evaluated prospectively in a cohort of 165 consecutive patients with recent-onset or early polyarthritis (EPA) followed for up to 30 months. Patients were treated according to current Good Clinical Practice standards. Predefined outcomes were severe arthritis and persistent arthritis. At inclusion, a median of 3 months after disease onset, 133 (81%) patients fulfilled at least four American College of Rheumatology criteria for rheumatoid arthritis and 30 (18%) had erosive changes on radiographs of hands and feet. Disease-modifying anti-rheumatic drugs were used in close to 80% of the patients at 30 months. Joint damage increased linearly over time, whereas disease activity declined markedly and remained low at each follow-up. Autoantibodies were identified in 76 (46%) patients: rheumatoid factor (RF) in 68 (41%), anti-CCP in 53 (33%), and anti-Sa in 46 (28%). All three antibodies were correlated, but anti-Sa antibodies best predicted severity at 18 and 30 months. RF and anti-CCP performed less well. For both outcomes, anti-Sa alone performed better than any combination of antibodies. The presence of any autoantibody identified about 50 to 60% of the patients with poor outcomes. In multivariate analysis, anti-Sa (odds ratio (OR) 8.83), the presence of erosions at inclusion (OR 3.47) and increasing age (OR 1.06/year) were significantly associated with severity, whereas RF and anti-CCP were not significant predictors. Persistent arthritis was present in up to 84% of patients; autoantibodies were specific but poorly sensitive predictors of this outcome. We conclude that assays for antibodies against citrullinated antigens differ in their ability to predict poorer outcomes in patients with EPA. In our EPA cohort treated in accordance with current standards, detection of anti-Sa but not of RF or anti-CCP antibodies, in combination with clinical and radiological variables present at the first encounter, allowed the identification of a subgroup of EPA patients suffering more rapid and more severe joint damage over 30 months.

Prostaglandin EP4 receptor agonist protects against acute neurotoxicity

Under various abnormal physiologic conditions, overactivation of glutamate-gated ion channel receptor family members, including NMDA receptors, causes increase in COX-2 expression and generation of prostaglandins. PGE(2) exerts its physiologic actions mainly through its PGE(2) prostanoid (EP) receptors. In the present study, the role of the EP4 receptor against NMDA-induced excitotoxicity was investigated. Using the EP4 receptor agonist ONO-AE1-329, which has relative selectivity toward murine EP receptors on the order of EP1:EP2:EP3:EP4 of >1000:210:120:1, respectively, we questioned whether activation of the EP4 receptors has the potential to attenuate injury in brain. Mice were pretreated by intracerebroventricular injection with different doses of ONO-AE1-329 (0.1, 1, and 10 nmol; n = 9/group) and, after 20 min, by a single unilateral intrastriatal injection of NMDA (15 nmol, n = 12). NMDA injection produced a significant lesion in the ipsilateral striatum. This lesion volume was significantly reduced in groups that were pretreated with ONO-AE1-329, with maximum protection of more than 32% at 10 nmol. This is the first study revealing the protective effect of ONO-AE1-329 in an acute model of excitotoxicity in brain, and it suggests that preferential stimulation of EP4 receptors attenuates excitotoxic brain injury.

Production of Prostaglandin D2 by Human Osteoblasts and Modulation of Osteoprotegerin, RANKL, and Cellular Migration by DP and CRTH2 Receptors†‡

Human osteoblasts produce PGD2, which acts on the DP receptor to decrease osteoprotegerin production and on the CRTH2 receptor to decrease RANKL expression and to induce osteoblast chemotaxis. These results indicate that activation of CRTH2 may lead to an anabolic response in bone.

PGD2 DP1 receptor protects brain from ischemia-reperfusion injury

Prostaglandin D2 is the most abundant prostaglandin in the brain. It has long been described as a modulator of the neuroinflammatory process, but little is known regarding the role of its Gαs‐coupled receptor, DP1. Therefore, in this study, the effect of the DP1 receptor on the outcome of cerebral ischemia in wildtype (WT) and DP1 knockout (DP1–/–) C57Bl/6 mice was investigated. Ischemia‐reperfusion injury was produced by a 90‐min occlusion of the right middle cerebral artery followed by a 4‐day reperfusion. Infarct size was 49.0 ± 11.0% larger in DP1–/– mice (n = 11; P < 0.01) than in WT mice (n = 9 per group). However, no differences were detected in the relative cerebral blood flow (CBF) or any of the physiological parameters measured (n = 5 per group) or in the large blood vessel anatomy (n = 3 per group). To further address whether the DP1 protective role in the brain could be extended to neurons, mouse primary corticostriatal neuronal cultures were exposed to the DP1‐selective agonist, BW245C, which provided dose‐dependent protection against excitotoxicity induced by glutamate. Protection was significant at a dose as low as 0.05 µm. The results indicate that the DP1 receptor is neuroprotective in both in vivo and in vitro paradigms. Development of drugs to stimulate the DP1 receptor in brain could provide a new therapeutic strategy against cerebral ischemia and potentially other neurological conditions.

Characterization of the PGE2 receptor subtype in bovine chondrocytes in culture.

1 . Prostaglandin E2 (PGE2) is an autacoid that decreases proteoglycan synthesis, increases metalloprotease production by cultured chondrocytes, and can modulate some of the actions of interleukin‐1 on cartilage. The objective of the present study was to characterize the subtype of prostaglandin E2 receptor present in bovine chondrocytes in culture. 2 . Primary cultures of articular chondrocytes were prepared from slices of bovine carpal cartilage by sequential digestion with type III hyaluronidase, trypsin, type II collagenase, followed by overnight incubation in Dulbeccos Modified Eagles Medium (DMEM) with type II collagenase, washing, and seeding at a density of 2 × 105 cells cm−2 in DMEM with 10% foetal bovine serum. 3 . PGE2 and carbaprostacyclin induced dose‐dependent increases in intracellular cyclic AMP in bovine chondrocytes in culture. The potencies of these compounds were different, and maximal doses of PGE2 and carbaprostacyclin had an additive effect. PGD2 induced a small increase in intracellular cyclic AMP only at a high concentration (10−5 m). 4 . PGE2 was more potent that the EP2 agonist 11‐deoxy‐PGE1 at inducing increases in intracellular cyclic AMP. The EP2 agonist butaprost, however, induced only a small increase at a concentration of 10−5 m. 17‐Phenyl‐PGE2 (EP1 agonist), sulprostone and MB 28767 (15S‐hydroxy‐9‐oxo‐16‐phenoxy‐γ‐tetranorprost‐13E‐enoic acid) (EP3 agonists) did not induce an increase in intracellular cyclic AMP at concentrations up to 10−5 m. 5 . The EP4 antagonist AH 23848B ([1α(Z),2β,5α]‐(±)‐7‐[5‐[[(1,1′‐biphenyl)‐4‐yl]methoxy]‐2‐(4‐morpholinyl)‐3‐oxocyclopentyl]‐5‐heptenoic acid) antagonized PGE2 but not carbaprostacyclin effects on intracellular cyclic AMP. The Schild plot slope was different from 1 but this could be due to an interaction of PGE2 with IP receptors in high doses. The exact nature of the antagonism by compound AH 23848B could not be definitely established in these experimental conditions. 6 . Neither PGE2 nor any of its analogues inhibited the increase in intracellular cyclic AMP induced by forskolin, and pertussis toxin did not alter the response to PGE2, suggesting that no Gi‐coupled PGE2 receptors are present in these cells. Stimulation with PGE2 did not induce significant increases in intracellular inositol‐trisphosphate levels nor increases in intracellular free calcium as determined by confocal microscopy, suggesting the absence of phospholipase‐C‐coupled or of calcium channel‐coupled PGE2 receptors in bovine chondrocytes in these experimental conditions. 7 . These results show for the first time that bovine chondrocytes in culture present a functional PGE2 receptor that has some pharmacological characteristics of an EP4 subtype, as well as an IP receptor.

The DERAA HLA-DR alleles in patients with early polyarthritis: protection against severe disease and lack of association with rheumatoid arthritis autoantibodies.

OBJECTIVE To define the association of alleles encoding the HLA-DR rheumatoid arthritis (RA) protective epitope (DERAA) with the presence of RA-associated antibodies at study inclusion and with severe outcome in patients with early polyarthritis (EPA). METHODS Consecutive EPA patients (n = 210) were evaluated early (mean of 4.8 months after diagnosis) and prospectively (for 30 months). HLA class II typing was performed by polymerase chain reaction using sequence-specific primers, and HLA-DR alleles DERAA, RA-associated shared epitope (SE), and non-SE/non-DERAA (neither SE nor DERAA) were identified. RA-associated antibodies identified were anti-Sa/citrullinated vimentin, anti-cyclic citrullinated peptide 2, and IgM rheumatoid factor. Severe disease was defined according to a preset threshold of joint destruction and/or functional limitation. RESULTS DERAA and SE alleles were present in 62 and 110 of the 210 EPA patients, respectively. At 30 months, severe disease was present in 78 patients (37%). In contrast to SE alleles, DERAA alleles were not associated with the production of RA-associated antibodies, but were strongly protective against severe disease at 30 months (odds ratio 0.30, P < 0.001). DERAA alleles emerged as a strong, independent protective marker on multivariate analysis. The protective effect of DERAA was seen only in patients who did not already have erosions at study inclusion, was independent of the presence of antibodies, but was not associated with spontaneous remission. CONCLUSION In our EPA cohort, the presence of a DERAA sequence was a strong independent predictor of a better prognosis, but only in the absence of erosive disease that was already present at inclusion. Identification of DERAA alleles may help in managing the large subgroup of EPA patients who do not have erosions at baseline.

Effects of valeryl salicylate, a COX-1 inhibitor, on models of acute inflammation in mice

The effect of valeryl salicylate (VS), an inhibitor of cyclooxygenase-1 (COX-1), was evaluated in arachidonic acid or croton oil-induced ear oedema and carrageenan-induced paw oedema in mice. Ear oedema was induced by topical administration of arachidonic acid (2mg per ear; 20 microliters) or croton oil (1mg per ear; 20 microliters) to the inner surface of the left ear and the change in the ears thickness was measured with a precision micrometer (Fisher, USA). VS significantly inhibited the arachidonic acid ear oedema after lh at doses of 1.5-45 micrograms per ear; however, only at the dose of 45 micrograms per ear was it able to significantly reduce the croton oil-induced oedema at 6h. Paw oedema was induced by the injection of 25 microliters of 1% carrageenan into the plantar aponeurosis of the right hind paw. The oedema was evaluated at 0.5, 1, 2, 4, 24, 48 and 72h. Previously in our experiments, we observed two peaks in paw oedema formation: one at 2h, in the early phase (0-4h), and the other, occurring at 48h after carrageenan injection, in the late phase (24-72h). The pre-treatment with VS significantly reduced the paw oedema at 2h, the same effect observed with celecoxib and indomethacin treatments. At 24h, VS did not inhibit oedema but significantly increased it mainly at 48h after carrageenan injection. These results showed that VS was pharmacologically active in these models and suggest that COX-1 may participate in the early and late phases of inflammation in the models studied.

Nitric oxide and cyclooxygenase may participate in the analgesic and anti-inflammatory effect of the cucurbitacins fraction from Wilbrandia ebracteata.

Wilbrandia ebracteata is a medicinal plant from South America used in folk medicine for the treatment of chronic rheumatic diseases. We have shown that the high performance liquid chromatography-characterized (HPLC) dichloromethane fraction isolated from Wilbrandia ebracteata (WEDC) inhibits the parameters observed in experimental models of inflammation in vivo and in vitro. In the present study, we extend our previous observations on the analgesic effects of WEDC by investigating its actions using the hot plate test and zymosan-induced writhing test in mice, as well as zymosan-induced arthritis in rats evaluating articular inflammatory pain, cell migration and determination of NO release into the joint exudate. The effect of WEDC on the activity of COX-1 and COX-2 in vitro and its ulcerogenic capacity in vivo were also investigated. The oral treatment of the animals with WEDC (1-10 mg/kg) produced a significant, dose-dependent reduction of articular incapacitation and abdominal contortions in the writhing test. The same effect was not observed in the hot plate and rota-rod tests. WEDC also reduced nitrite release into the zymosan-inflamed joints. In the evaluation of COX activity, we observed that WEDC was able to selectively inhibit COX-2 but not COX-1 activity in COS-7 cells. Moreover, WEDC treatment did not show gastrointestinal toxicity. Our data confirm the anti-nociceptive activities of the WEDC and indicate that this effect could be associated with inhibition of cyclooxygenase-2 (COX-2) and nitric oxide release. The effects could be attributed to cucurbitacins since several of these were isolated from the WEDC.

Monocytes from patients with osteoarthritis display increased osteoclastogenesis and bone resorption: the In Vitro Osteoclast Differentiation in Arthritis study.

OBJECTIVE To compare the osteoclastogenic capacity of peripheral blood mononuclear cells (PBMCs) from patients with osteoarthritis (OA) to that of PBMCs from self-reported normal individuals. METHODS PBMCs from 140 patients with OA and 45 healthy donors were assayed for CD14+ expression and induced to differentiate into osteoclasts over 3 weeks in vitro. We assessed the number of osteoclasts, their resorptive activity, osteoclast apoptosis, and expression of the following cytokine receptors: RANK, interleukin-1 receptor type I (IL-1RI), and IL-1RII. A ridge logistic regression classifier was developed to discriminate OA patients from controls. RESULTS PBMCs from OA patients gave rise to more osteoclasts that resorbed more bone surface than did PBMCs from controls. The number of CD14+ precursors was comparable in both groups, but there was less apoptosis in osteoclasts obtained from OA patients. Although no correlation was found between osteoclastogenic capacity and clinical or radiographic scores, levels of IL-1RI were significantly lower in cultures from patients with OA than in cultures from controls. Osteoclast apoptosis and expression levels of IL-1RI and IL-1RII were used to build a multivariate predictive model for OA. CONCLUSION During 3 weeks of culture under identical conditions, monocytes from patients with OA display enhanced capacity to generate osteoclasts compared to cells from controls. Enhanced osteoclastogenesis is accompanied by increased resorptive activity, reduced osteoclast apoptosis, and diminished IL-1RI expression. These findings support the possibility that generalized changes in bone metabolism affecting osteoclasts participate in the pathophysiology of OA.

Outcomes in recent‐onset inflammatory polyarthritis differ according to initial titers, persistence over time, and specificity of the autoantibodies

To prospectively evaluate the predictive value of initial titers and subsequent variations of 3 rheumatoid arthritis–associated antibodies for outcomes at 30 months in patients with recent‐onset polyarthritis.