Elevated body temperature is associated with depressive symptoms: results from the TemPredict Study.

Correlations between altered body temperature and depression have been reported in small samples; greater confidence in these associations would provide a rationale for further examining potential mechanisms of depression related to body temperature regulation. We sought to test the hypotheses that greater depression symptom severity is associated with (1) higher body temperature, (2) smaller differences between body temperature when awake versus asleep, and (3) lower diurnal body temperature amplitude. Data collected included both self-reported body temperature (using standard thermometers), wearable sensor-assessed distal body temperature (using an off-the-shelf wearable sensor that collected minute-level physiological data), and self-reported depressive symptoms from > 20,000 participants over the course of ~ 7 months as part of the TemPredict Study. Higher self-reported and wearable sensor-assessed body temperatures when awake were associated with greater depression symptom severity. Lower diurnal body temperature amplitude, computed using wearable sensor-assessed distal body temperature data, tended to be associated with greater depression symptom severity, though this association did not achieve statistical significance. These findings, drawn from a large sample, replicate and expand upon prior data pointing to body temperature alterations as potentially relevant factors in depression etiology and may hold implications for development of novel approaches to the treatment of major depressive disorder.

Fatty acids negatively regulate platelet function through formation of noncanonical 15-lipoxygenase-derived eicosanoids.

The antiplatelet effect of polyunsaturated fatty acids is primarily attributed to its metabolism to bioactive metabolites by oxygenases, such as lipoxygenases (LOX). Platelets have demonstrated the ability to generate 15-LOX-derived metabolites (15-oxylipins); however, whether 15-LOX is in the platelet or is required for the formation of 15-oxylipins remains unclear. This study seeks to elucidate whether 15-LOX is required for the formation of 15-oxylipins in the platelet and determine their mechanistic effects on platelet reactivity. In this study, 15-HETrE, 15-HETE, and 15-HEPE attenuated collagen-induced platelet aggregation, and 15-HETrE inhibited platelet aggregation induced by different agonists. The observed anti-aggregatory effect was due to the inhibition of intracellular signaling including αIIbß3 and protein kinase C activities, calcium mobilization, and granule secretion. While 15-HETrE inhibited platelets partially through activation of peroxisome proliferator-activated receptor ß (PPARß), 15-HETE also inhibited platelets partially through activation of PPARα. 15-HETrE, 15-HETE, or 15-HEPE inhibited 12-LOX in vitro, with arachidonic acid as the substrate. Additionally, a 15-oxylipin-dependent attenuation of 12-HETE level was observed in platelets following ex vivo treatment with 15-HETrE, 15-HETE, or 15-HEPE. Platelets treated with DGLA formed 15-HETrE and collagen-induced platelet aggregation was attenuated only in the presence of ML355 or aspirin, but not in the presence of 15-LOX-1 or 15-LOX-2 inhibitors. Expression of 15-LOX-1, but not 15-LOX-2, was decreased in leukocyte-depleted platelets compared to non-depleted platelets. Taken together, these findings suggest that 15-oxylipins regulate platelet reactivity; however, platelet expression of 15-LOX-1 is low, suggesting that 15-oxylipins may be formed in the platelet through a 15-LOX-independent pathway.

Feasibility of Targeted Delivery of AAV5-GFP into the Cerebellum of Nonhuman Primates Following a Single Convection-Enhanced Delivery Infusion.

In this study, we built upon our previous work to demonstrate the distribution and transport of AAV5-green fluorescent protein (GFP) following a single convection-enhanced delivery infusion into the nonhuman primate cerebellum, with no untoward side effects noted. Dosing under magnetic resonance imaging guidance revealed a sixfold larger volume of distribution compared with the volume of infusion, with no evidence of reflux underscoring the convective properties of the cerebellum and step design of the cannula. Postmortem tissue analysis, 4 weeks post-adeno-associated viral (AAV) delivery, revealed the robust presence of the transgene in situ, with GFP detection in secondary regions not directly targeted by the infusion, denoting distal transport of the vector. Irrespective of tropism, a twofold larger area of transgene expression was found and was corroborated against the presence of contrast on T1-weighted images. Different levels of transduction were detected between animals, which were negatively correlated with the level of antibody titer against the GFP construct, whereby the higher the antibody titer, the lower the level of transgene expression. These findings support the use of the posterior fossa as a potential target site for direct delivery of gene-based therapeutics for cerebellar diseases.

5 S,15 S-Dihydroperoxyeicosatetraenoic Acid (5,15-diHpETE) as a Lipoxin Intermediate: Reactivity and Kinetics with Human Leukocyte 5-Lipoxygenase, Platelet 12-Lipoxygenase, and Reticulocyte 15-Lipoxygenase-1.

The reaction of 5 S,15 S-dihydroperoxyeicosatetraenoic acid (5,15-diHpETE) with human 5-lipoxygenase (LOX), human platelet 12-LOX, and human reticulocyte 15-LOX-1 was investigated to determine the reactivity and relative rates of producing lipoxins (LXs). 5-LOX does not react with 5,15-diHpETE, although it can produce LXA4 when 15-HpETE is the substrate. In contrast, both 12-LOX and 15-LOX-1 react with 5,15-diHpETE, forming specifically LXB4. For 12-LOX and 5,15-diHpETE, the kinetic parameters are kcat = 0.17 s-1 and kcat/ KM = 0.011 µM-1 s-1 [106- and 1600-fold lower than those for 12-LOX oxygenation of arachidonic acid (AA), respectively]. On the other hand, for 15-LOX-1 the equivalent parameters are kcat = 4.6 s-1 and kcat/ KM = 0.21 µM-1 s-1 (3-fold higher and similar to those for 12-HpETE formation by 15-LOX-1 from AA, respectively). This contrasts with the complete lack of reaction of 15-LOX-2 with 5,15-diHpETE [Green, A. R., et al. (2016) Biochemistry 55, 2832-2840]. Our data indicate that 12-LOX is markedly inferior to 15-LOX-1 in catalyzing the production of LXB4 from 5,15-diHpETE. Platelet aggregation was inhibited by the addition of 5,15-diHpETE, with an IC50 of 1.3 µM; however, LXB4 did not significantly inhibit collagen-mediated platelet activation up to 10 µM. In summary, LXB4 is the primary product of 12-LOX and 15-LOX-1 catalysis, if 5,15-diHpETE is the substrate, with 15-LOX-1 being 20-fold more efficient than 12-LOX. LXA4 is the primary product with 5-LOX but only if 15-HpETE is the substrate. Approximately equal proportions of LXA4 and LXB4 are produced by 12-LOX but only if LTA4 is the substrate, as described previously [Sheppard, K. A., et al. (1992) Biochim. Biophys. Acta 1133, 223-234].

First Selective 12-LOX Inhibitor, ML355, Impairs Thrombus Formation and Vessel Occlusion In Vivo With Minimal Effects on Hemostasis.

OBJECTIVE: Adequate platelet reactivity is required for maintaining hemostasis. However, excessive platelet reactivity can also lead to the formation of occlusive thrombi. Platelet 12(S)-lipoxygenase (12-LOX), an oxygenase highly expressed in the platelet, has been demonstrated to regulate platelet function and thrombosis ex vivo, supporting a key role for 12-LOX in the regulation of in vivo thrombosis. However, the ability to pharmacologically target 12-LOX in vivo has not been established to date. Here, we studied the effect of the first highly selective 12-LOX inhibitor, ML355, on in vivo thrombosis and hemostasis. APPROACH AND RESULTS: ML355 dose-dependently inhibited human platelet aggregation and 12-LOX oxylipin production, as confirmed by mass spectrometry. Interestingly, the antiplatelet effects of ML355 were reversed after exposure to high concentrations of thrombin in vitro. Ex vivo flow chamber assays confirmed that human platelet adhesion and thrombus formation at arterial shear over collagen were attenuated in whole blood treated with ML355 comparable to aspirin. Oral administration of ML355 in mice showed reasonable plasma drug levels by pharmacokinetic assessment. ML355 treatment impaired thrombus growth and vessel occlusion in FeCl3-induced mesenteric and laser-induced cremaster arteriole thrombosis models in mice. Importantly, hemostatic plug formation and bleeding after treatment with ML355 was minimal in mice in response to laser ablation on the saphenous vein or in a cremaster microvasculature laser-induced rupture model. CONCLUSIONS: Our data strongly support 12-LOX as a key determinant of platelet reactivity in vivo, and inhibition of platelet 12-LOX with ML355 may represent a new class of antiplatelet therapy.

12(S)-HETrE, a 12-Lipoxygenase Oxylipin of Dihomo-γ-Linolenic Acid, Inhibits Thrombosis via Gαs Signaling in Platelets.

OBJECTIVE: Dietary supplementation with polyunsaturated fatty acids has been widely used for primary and secondary prevention of cardiovascular disease in individuals at risk; however, the cardioprotective benefits of polyunsaturated fatty acids remain controversial because of lack of mechanistic and in vivo evidence. We present direct evidence that an omega-6 polyunsaturated fatty acid, dihomo-γ-linolenic acid (DGLA), exhibits in vivo cardioprotection through 12-lipoxygenase (12-LOX) oxidation of DGLA to its reduced oxidized lipid form, 12(S)-hydroxy-8Z,10E,14Z-eicosatrienoic acid (12(S)-HETrE), inhibiting platelet activation and thrombosis. APPROACH AND RESULTS: DGLA inhibited ex vivo platelet aggregation and Rap1 activation in wild-type mice, but not in mice lacking 12-LOX expression (12-LOX(-/-)). Similarly, wild-type mice treated with DGLA were able to reduce thrombus growth (platelet and fibrin accumulation) after laser-induced injury of the arteriole of the cremaster muscle, but not 12-LOX(-/-) mice, supporting a 12-LOX requirement for mediating the inhibitory effects of DGLA on platelet-mediated thrombus formation. Platelet activation and thrombus formation were also suppressed when directly treated with 12(S)-HETrE. Importantly, 2 hemostatic models, tail bleeding and arteriole rupture of the cremaster muscle, showed no alteration in hemostasis after 12(S)-HETrE treatment. Finally, the mechanism for 12(S)-HETrE protection was shown to be mediated via a Gαs-linked G-protein-coupled receptor pathway in human platelets. CONCLUSIONS: This study provides the direct evidence that an omega-6 polyunsaturated fatty acid, DGLA, inhibits injury-induced thrombosis through its 12-LOX oxylipin, 12(S)-HETrE, which strongly supports the potential cardioprotective benefits of DGLA supplementation through its regulation of platelet function. Furthermore, this is the first evidence of a 12-LOX oxylipin regulating platelet function in a Gs α subunit-linked G-protein-coupled receptor-dependent manner.

Strict Regiospecificity of Human Epithelial 15-Lipoxygenase-2 Delineates Its Transcellular Synthesis Potential.

Lipoxins are an important class of lipid mediators that induce the resolution of inflammation and arise from transcellular exchange of arachidonic acid (AA)-derived lipoxygenase products. Human epithelial 15-lipoxygenase-2 (h15-LOX-2), the major lipoxygenase in macrophages, has exhibited strict regiospecificity, catalyzing only the hydroperoxidation of carbon 15 of AA. To determine the catalytic potential of h15-LOX-2 in transcellular synthesis events, we reacted it with the three lipoxygenase-derived monohydroperoxy-eicosatetraenoic acids (HPETE) in humans: 5-HPETE, 12-HPETE, and 15-HPETE. Only 5-HPETE was a substrate for h15-LOX-2, and the steady-state catalytic efficiency (kcat/Km) of this reaction was 31% of the kcat/Km of AA. The only major product of h15-LOX-2's reaction with 5-HPETE was the proposed lipoxin intermediate, 5,15-dihydroperoxy-eicosatetraenoic acid (5,15-diHPETE). However, h15-LOX-2 did not react further with 5,15-diHPETE to produce lipoxins. This result is consistent with the specificity of h15-LOX-2 despite the increased reactivity of 5,15-diHPETE. Density functional theory calculations determined that the radical, after abstracting the C10 hydrogen atom from 5,15-diHPETE, had an energy 5.4 kJ/mol lower than that of the same radical generated from AA, demonstrating the facility of 5,15-diHPETE to form lipoxins. Interestingly, h15-LOX-2 does react with 5S,6R-diHETE, forming LipoxinA4, indicating the gemdiol does not prohibit h15-LOX-2 reactivity. Taken together, these results demonstrate the strict regiospecificity of h15-LOX-2 that circumscribes its role in transcellular synthesis.

Substrate binding properties of potato tuber ADP-glucose pyrophosphorylase as determined by isothermal titration calorimetry.

Substrate binding properties of the large (LS) and small (SS) subunits of potato tuber ADP-glucose pyrophosphorylase were investigated by using isothermal titration calorimetry. Our results clearly show that the wild type heterotetramer (S(WT)L(WT)) possesses two distinct types of ATP binding sites, whereas the homotetrameric LS and SS variant forms only exhibited properties of one of the two binding sites. The wild type enzyme also exhibited significantly increased affinity to this substrate compared to the homotetrameric enzyme forms. No stable binding was evident for the second substrate, glucose-1-phosphate, in the presence or absence of ATPγS suggesting that interaction of glucose-1-phosphate is dependent on hydrolysis of ATP and supports the Theorell-Chance bi bi reaction mechanism.

Large-vessel giant cell arteritis: a cohort study.

OBJECTIVE: The aim of this study was to compare baseline variables, treatment and outcomes in patients with large-vessel GCA (LV-GCA), primarily of the upper extremities, with those with cranial disease (C-GCA). METHODS: All patients >50 years of age with radiographic evidence of subclavian LV-GCA diagnosed between 1 January 1999 and 31 December 2008 were identified and compared with those with biopsy-positive C-GCA diagnosed in the same period. RESULTS: The study included 120 LV-GCA patients and 212 C-GCA patients. Compared with C-GCA, patients with LV-GCA were younger [68.2 years (s.d. 7.5) vs 75.7 (7.4), P < 0.001] and had longer duration of symptoms at GCA diagnosis (median 3.5 vs 2.2 months, P < 0.001). A history of PMR was more common in LV-GCA patients (26% vs 15%, P = 0.012), but a smaller proportion had cranial symptoms (41% vs 83%, P < 0.001) and vision loss (4% vs 11%, P = 0.035). ACR classification criteria for GCA were satisfied in 39% of LV-GCA patients and 95% of C-GCA patients (P < 0.001). Compared with C-GCA, patients with LV-GCA had more relapses (4.9 vs 3.0/10 person-years, P < 0.001), higher cumulative corticosteroid (CS) doses at 1 year [11.4 g (s.d. 5.9) vs 9.1 (s.d. 3.7), P < 0.001] and required longer treatment (median 4.5 vs 2.2 years, P < 0.001). CONCLUSION: Although patients with LV-GCA had a lower rate of vision loss, they had a higher relapse rate and greater CS requirements. The ACR criteria for GCA are inadequate for the classification of patients with LV-GCA.

Longterm blood pressure variability in patients with rheumatoid arthritis and its effect on cardiovascular events and all-cause mortality in RA: a population-based comparative cohort study.

OBJECTIVE: To examine longterm visit-to-visit blood pressure (BP) variability in patients with rheumatoid arthritis (RA) versus non-RA subjects and to assess its effect on cardiovascular (CV) events and mortality in RA. METHODS: Clinic BP measures were collected in a population-based incident cohort of patients with RA (1987 American College of Rheumatology criteria met between January 1, 1995, and January 1, 2008) and non-RA subjects. BP variability was defined as within-subject SD in systolic and diastolic BP. RESULTS: The study included 442 patients with RA (mean age 55.5 yrs, 70% females) and 424 non-RA subjects (mean age 55.7 yrs, 69% females). Patients with RA had higher visit-to-visit variability in systolic BP (13.8 ± 4.7 mm Hg) than did non-RA subjects (13.0 ± 5.2 mm Hg, p = 0.004). Systolic BP variability declined after the index date in RA (p < 0.001) but not in the non-RA cohort (p = 0.73), adjusting for age, sex, and calendar year of RA. During the mean followup of 7.1 years, 33 CV events and 57 deaths occurred in the RA cohort. Visit-to-visit systolic BP variability was associated with increased risk of CV events (HR per 1 mm Hg increase in BP variability 1.12, 95% CI 1.01-1.25). Diastolic BP variability was associated with all-cause mortality in RA (HR 1.14, 95% CI 1.03-1.27), adjusting for systolic and diastolic BP, body mass index, smoking, diabetes, dyslipidemia, and use of antihypertensives. CONCLUSION: Patients with RA had higher visit-to-visit systolic BP variability than did non-RA subjects. There was a significant decline in systolic BP variability after RA incidence. Higher visit-to-visit BP variability was associated with adverse CV outcomes and all-cause mortality in RA.

Determination of the Structure and Catalytic Mechanism of Sorghum bicolor Caffeic Acid O-Methyltransferase and the Structural Impact of Three brown midrib12 Mutations.

Using S-adenosyl-methionine as the methyl donor, caffeic acid O-methyltransferase from sorghum (Sorghum bicolor; SbCOMT) methylates the 5-hydroxyl group of its preferred substrate, 5-hydroxyconiferaldehyde. In order to determine the mechanism of SbCOMT and understand the observed reduction in the lignin syringyl-to-guaiacyl ratio of three brown midrib12 mutants that carry COMT gene missense mutations, we determined the apo-form and S-adenosyl-methionine binary complex SbCOMT crystal structures and established the ternary complex structure with 5-hydroxyconiferaldehyde by molecular modeling. These structures revealed many features shared with monocot ryegrass (Lolium perenne) and dicot alfalfa (Medicago sativa) COMTs. SbCOMT steady-state kinetic and calorimetric data suggest a random bi-bi mechanism. Based on our structural, kinetic, and thermodynamic results, we propose that the observed reactivity hierarchy among 4,5-dihydroxy-3-methoxycinnamyl (and 3,4-dihydroxycinnamyl) aldehyde, alcohol, and acid substrates arises from the ability of the aldehyde to stabilize the anionic intermediate that results from deprotonation of the 5-hydroxyl group by histidine-267. Additionally, despite the presence of other phenylpropanoid substrates in vivo, sinapaldehyde is the preferential product, as demonstrated by its low Km for 5-hydroxyconiferaldehyde. Unlike its acid and alcohol substrates, the aldehydes exhibit product inhibition, and we propose that this is due to nonproductive binding of the S-cis-form of the aldehydes inhibiting productive binding of the S-trans-form. The S-cis-aldehydes most likely act only as inhibitors, because the high rotational energy barrier around the 2-propenyl bond prevents S-trans-conversion, unlike alcohol substrates, whose low 2-propenyl bond rotational energy barrier enables rapid S-cis/S-trans-interconversion.

Characterization of Solanum tuberosum multicystatin and the significance of core domains.

Potato (Solanum tuberosum) multicystatin (PMC) is a unique cystatin composed of eight repeating units, each capable of inhibiting cysteine proteases. PMC is a composite of several cystatins linked by trypsin-sensitive (serine protease) domains and undergoes transitions between soluble and crystalline forms. However, the significance and the regulatory mechanism or mechanisms governing these transitions are not clearly established. Here, we report the 2.2-Šcrystal structure of the trypsin-resistant PMC core consisting of the fifth, sixth, and seventh domains. The observed interdomain interaction explains PMC's resistance to trypsin and pH-dependent solubility/aggregation. Under acidic pH, weakening of the interdomain interactions exposes individual domains, resulting in not only depolymerization of the crystalline form but also exposure of cystatin domains for inhibition of cysteine proteases. This in turn allows serine protease-mediated fragmentation of PMC, producing ∼ 10-kD domains with intact inhibitory capacity and faster diffusion, thus enhancing PMC's inhibitory ability toward cysteine proteases. The crystal structure, light-scattering experiments, isothermal titration calorimetry, and site-directed mutagenesis confirmed the critical role of pH and N-terminal residues in these dynamic transitions between monomer/polymer of PMC. Our data support a notion that the pH-dependent structural regulation of PMC has defense-related implications in tuber physiology via its ability to regulate protein catabolism.

Immune response profiling in early rheumatoid arthritis: discovery of a novel interaction of treatment response with viral immunity.

INTRODUCTION: It remains challenging to predict the outcomes of therapy in patients with rheumatoid arthritis (RA). The objective of this study was to identify immune response signatures that correlate with clinical treatment outcomes in patients with RA. METHODS: A cohort of 71 consecutive patients with early RA starting treatment with disease-modifying antirheumatic drugs (DMARDs) was recruited. Disease activity at baseline and after 21 to 24 weeks of follow-up was measured using the Disease Activity Score in 28 joints (DAS28). Immune response profiling was performed by analyzing multi-cytokine production from peripheral blood cells following incubation with a panel of stimuli, including a mixture of human cytomegalovirus (CMV) and Epstein-Barr virus (EBV) lysates. Profiles identified via principal components analysis (PCA) for each stimulus were then correlated with the ΔDAS28 from baseline to follow-up. A clinically meaningful improvement in the DAS28 was defined as a decrease of ≥1.2. RESULTS: A profile of T-cell cytokines (IL-13, IL-4, IL-5, IL-2, IL-12, and IFN-γ) produced in response to CMV/EBV was found to correlate with the ΔDAS28 from baseline to follow-up. At baseline, a higher magnitude of the CMV/EBV immune response profile predicted inadequate DAS28 improvement (mean PCA-1 scores: 65.6 versus 50.2; P = 0.029). The baseline CMV/EBV response was particularly driven by IFN-γ (P = 0.039) and IL-4 (P = 0.027). Among patients who attained clinically meaningful DAS28 improvement, the CMV/EBV PCA-1 score increased from baseline to follow-up (mean +11.6, SD 25.5), whereas among patients who responded inadequately to DMARD therapy, the CMV/EBV PCA-1 score decreased (mean -12.8, SD 25.4; P = 0.002). Irrespective of the ΔDAS28, methotrexate use was associated with up-regulation of the CMV/EBV response. The CMV/EBV profile was associated with positive CMV IgG (P <0.001), but not EBV IgG (P = 0.32), suggesting this response was related to CMV exposure. CONCLUSIONS: A profile of T-cell immunity associated with CMV exposure influences the clinical response to DMARD therapy in patients with early RA. Because CMV latency is associated with greater joint destruction, our findings suggest that changes in T-cell immunity mediated by viral persistence may affect treatment response and possibly long-term outcomes of RA.

Impact of statin use on lipid levels in statin-naive patients with rheumatoid arthritis versus non-rheumatoid arthritis subjects: results from a population-based study.

OBJECTIVE: To examine lipid profiles among statin-naive patients with rheumatoid arthritis (RA) and those without RA before and after the initiation of statins. METHODS: Information regarding lipid measures and statin use was gathered in a population-based incident cohort of patients with RA (1987 American College of Rheumatology criteria first met between January 1, 1988 and January 1, 2008) and in a cohort of non-RA subjects from the same underlying population. Only patients with no prior history of statin use were included. RESULTS: The study included 161 patients with RA (mean age 56.3 years, 57% female) and 221 non-RA subjects (mean age 56.0 years, 66% female). Prior to the start of statins, the levels of total cholesterol and low-density lipoprotein (LDL) cholesterol were lower in the RA versus the non-RA cohort (P < 0.001 and P = 0.003, respectively). The absolute and percentage change in LDL cholesterol after at least 90 days of statin use tended to be smaller in the RA versus the non-RA cohort (P = 0.03 and P = 0.09, respectively). After at least 90 days of statin use, patients with RA were less likely to achieve therapeutic goals for LDL cholesterol than the non-RA subjects (P = 0.046). Increased erythrocyte sedimentation rate (ESR) at baseline (odds ratio 0.47, 95% confidence interval 0.26-0.85) was associated with lower likelihood of achieving therapeutic LDL goals. CONCLUSION: Patients with RA had lower total cholesterol and LDL cholesterol levels before statin initiation and lower likelihood of achieving therapeutic LDL goals following statin use than the non-RA subjects. Some RA disease characteristics, in particular ESR at baseline, may have an adverse impact on achieving therapeutic LDL goals.

Trends in serious infections in rheumatoid arthritis.

OBJECTIVE: To examine trends in the rates of serious infections among patients diagnosed with rheumatoid arthritis (RA) in 1995-2007 compared to rates previously reported from the same geographical area diagnosed 1955-1994. METHODS: A population-based inception cohort of patients with RA in 1995-2007 was assembled and followed through their complete medical records until death, migration, or December 31, 2008. All serious infections (requiring hospitalization or intravenous antibiotics) were recorded. Person-year (py) methods were used to compare rates of infection. RESULTS: Among 464 patients with incident RA in 1995-2007, 54 had ≥ 1 serious infection (178 total). These were compared to 609 patients with incident RA in 1955-1994 (290 experienced ≥ 1 serious infection; 740 total). The rate of serious infections declined from 9.6 per 100 py in the 1955-1994 cohort to 6.6 per 100 py in the 1995-2007 cohort. Serious gastrointestinal (GI) infection rates increased from 0.5 per 100 py in the 1955-1994 cohort to 1.25 per 100 py in the 1995-2007 cohort. Among patients with a history of serious infection, the rate of subsequent infection increased from 16.5 per 100 py in 1955-1994 to 37.4 per 100 py in 1995-2007. There was an increase in the rate of serious infections in patients who received biologic agents, but this did not reach significance. CONCLUSION: Aside from GI infections, the rate of serious infections in patients with RA has declined in recent years. However, the rate of subsequent infections was higher in recent years than previously reported.

Structural characterization of 2,6-dichloro-p-hydroquinone 1,2-dioxygenase (PcpA) from Sphingobium chlorophenolicum, a new type of aromatic ring-cleavage enzyme.

PcpA (2,6-dichloro-p-hydroquinone 1,2-dioxygenase) from Sphingobium chlorophenolicum, a non-haem Fe(II) dioxygenase capable of cleaving the aromatic ring of p-hydroquinone and its substituted variants, is a member of the recently discovered p-hydroquinone 1,2-dioxygenases. Here we report the 2.6 Å structure of PcpA, which consists of four ßαßßß motifs, a hallmark of the vicinal oxygen chelate superfamily. The secondary co-ordination sphere of the Fe(II) centre forms an extensive hydrogen-bonding network with three solvent exposed residues, linking the catalytic Fe(II) to solvent. A tight hydrophobic pocket provides p-hydroquinones access to the Fe(II) centre. The p-hydroxyl group is essential for the substrate-binding, thus phenols and catechols, lacking a p-hydroxyl group, do not bind to PcpA. Site-directed mutagenesis and kinetic analysis confirm the critical catalytic role played by the highly conserved His10, Thr13, His226 and Arg259. Based on these results, we propose a general reaction mechanism for p-hydroquinone 1,2-dioxygenases.

Incidence and time trends of herpes zoster in rheumatoid arthritis: a population-based cohort study.

OBJECTIVE: To determine the incidence, time trends, risk factors, and severity of herpes zoster in a population-based cohort of patients with newly diagnosed rheumatoid arthritis (RA) compared to a group of individuals without RA from the same population. METHODS: All residents of Olmsted County, Minnesota fulfilling for the first time the 1987 American College of Rheumatology criteria for RA between January 1, 1980 and December 31, 2007 and a cohort of similar residents without RA were assembled and followed by retrospective chart review until death, migration, or December 31, 2008. RESULTS: There was no difference in the presence of herpes zoster prior to the RA incidence/index date between the cohorts (P = 0.85). During followup, 84 patients with RA (rate 12.1 cases per 1,000 person-years) and 44 subjects without RA (rate 5.4 cases per 1,000 person-years) developed herpes zoster. Patients with RA were more likely to develop herpes zoster than those without RA (hazard ratio [HR] 2.4 [95% confidence interval (95% CI) 1.7-3.5]). Herpes zoster occurred more frequently in patients diagnosed with RA more recently (HR 1.06 per year [95% CI 1.02-1.10]). Erosive disease, previous joint surgery, and use of hydroxychloroquine and corticosteroids were significantly associated with the development of herpes zoster in RA. There was no apparent association of herpes zoster with the use of methotrexate or biologic agents. Complications of herpes zoster occurred at a similar rate in both cohorts. CONCLUSION: The incidence of herpes zoster is increased in RA and has risen in recent years. There also has been an increasing incidence of herpes zoster in more recent years in the general population. RA disease severity is associated with the development of herpes zoster.

Increased expression of ADAMTS13 mRNA correlates with ischemic cerebrovascular disease in systemic lupus erythematosus patients.

OBJECTIVE: We investigated ADAMTS13 (a disintegrin-like and metalloprotease with thrombospondin type 1 motif, member 13) messenger RNA levels as a biomarker of disease features in systemic lupus erythematosus. METHODS: We measured and compared messenger RNA (mRNA) levels of ADAMTS13 in peripheral blood cells in patients with systemic lupus erythematosus and healthy control subjects by whole-genome microarray. We retrospectively analyzed the correlations of ADAMTS13 mRNA expression with clinical features, laboratory parameters, therapeutic features, and disease activity (according to the Systemic Lupus Erythematosus Disease Activity Index). We also examined the association of three single nucleotide polymorphisms (rs4962145, rs2285467, and rs685523) of the ADAMTS13 gene with patient characteristics. RESULTS: In 309 patients, the median ADAMTS13 mRNA expression levels were significantly higher in blood cells of systemic lupus erythematosus patients than in 23 healthy controls (p = .03). Notably, ADAMTS13 mRNA expression levels were significantly higher in systemic lupus erythematosus patients with a history of stroke (p = .02) or transient ischemic attack (p = .02). Among the three single nucleotide polymorphisms analyzed, rs2285467 was significantly associated with stroke (p = .03) and anticardiolipin antibodies (p = .04). CONCLUSIONS: Increased expression of ADAMTS13 mRNA in blood cells is associated with the presence of ischemic cerebrovascular disease in systemic lupus erythematosus patients and suggests a potential role for ADAMTS13 in the pathogenesis of ischemic cerebrovascular disease in these patients.