950 resultados para Smooth muscle contractility


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Vascular dysfunction associated with two-kidney, one-clip (2K-1C) hypertension may result from both altered matrix metalloproteinase (MMP) activity and higher concentrations of reactive oxygen species (ROS). Doxycycline is considering the most potent MMP inhibitor of tetracyclines and attenuates 2K-1C hypertension-induced high blood pressure and chronic vascular remodeling. Doxycycline might also act as a ROS scavenger and this may contribute to the amelioration of some cardiovascular diseases associated with increased concentrations of ROS. We hypothesized that in addition to its MMP inhibitory effect, doxycycline attenuates oxidative stress and improves nitric oxide (NO) bioavailability in 2K-1C hypertension, thus improving hypertension-induced arterial endothelial dysfunction. Sham operated or 2K-1C hypertensive rats were treated with doxycycline 30 mg/kg/day (or vehicle). After 8 weeks of treatment, aortic rings were isolated to assess endothelium dependent vasorelaxation to A23187. Arterial and systemic levels of ROS were respectively measured using dihydroethidine (DHE) and thiobarbituric acid reactive substances (TBARS). Neutrophils-derived ROS were tested in vitro using the fluoroprobe Carboxy-H(2)DCFDA and human neutrophils stimulated with phorbol 12-myristate 13-acetate (PMA). NO levels were assessed in rat aortic endothelial cells by confocal microscopy. Aortic MMP activity was determined by in situ zymography. Doxycycline attenuated 2K-1C hypertension (169 +/- 17.3 versus 209 +/- 10.9 mm Hg in hypertensive controls, p < 0.05) and protected against hypertension-induced reduction in endothelium-dependent vasorelaxation to A23187 (p < 0.05). Doxycycline also decreased hypertension-induced oxidative stress (p <= 0.05), higher MMP activity (p < 0.01) and improved NO levels in aortic endothelial cells (p < 0.01). Therefore, doxycycline ameliorates 2K-1C hypertension-induced endothelial dysfunction in aortas by inhibiting oxidative stress generation and improving NO bioavailability, in addition to its inhibitory effects on MMP activity. (C) 2012 Elsevier Inc. All rights reserved.

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We investigated the role of reactive oxygen species (ROS) and nitric oxide (NO) in ethanol-induced relaxation. Vascular reactivity experiments showed that ethanol (0.03-200 mmol/L) induced relaxation in endothelium-intact and denuded rat aortic rings isolated from male Wistar rats. Pre-incubation of intact or denuded rings with L-NAME (non selective NOS inhibitor, 100 mu mol/L), 7-nitroindazole (selective nNOS inhibitor, 100 mu mol/L), ODQ (selective inhibitor of guanylyl cyclase enzyme, I mu mol/L), glibenclamide (selective blocker of ATP-sensitive K+ channels, 3 mu mol/L) and 4-aminopyridine (selective blocker of voltage-dependent K+ channels, 4-AP, 1 mmol/L) reduced ethanol-induced relaxation. Similarly, tiron (superoxide anion (O-2(-)) scavenger, 1 mmol/L) and catalase (hydrogen peroxide (H2O2) scavenger, 300 U/mL) reduced ethanol-induced relaxation to a similar extent in both endothelium-intact and denuded rings. Finally, prodifen (non-selective cytochrome P450 enzymes inhibitor, 10 mu mol/L) and 4-methylpyrazole (selective alcohol dehydrogenase inhibitor, 10 mu mol/L) reduced ethanol-induced relaxation. In cultured aortic vascular smooth muscle cells (VSMCs), ethanol stimulated generation of NO, which was significantly inhibited by L-NAME. In endothelial cells, flow cytometry studies showed that ethanol increased cytosolic Ca2+ concentration ([Ca2+]c), O-2(-) and cytosolic NO concentration ([NO]c). Tiron inhibited ethanol-induced increase in [Ca-2]c and [NO]c. The major new finding of this work is that ethanol induces relaxation via redox-sensitive and NO-cGMP-dependent pathways through direct effects on ROS production and NO signaling. These findings identify putative molecular mechanisms whereby ethanol, at pharmacological concentrations, influences vascular reactivity. (C) 2011 Elsevier Inc. All rights reserved.

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de Oliveira Alvim R, Lima Santos PCJ, Goncalves Dias R, Rodrigues MV, de Sa Cunha R, Mill JG, Junior WN, Krieger JE, Pereira AC. Association between the C242T polymorphism in the p22phox gene with arterial stiffness in the Brazilian population. Physiol Genomics 44: 587-592, 2012. First published April 10, 2012; doi:10.1152/physiolgenomics.00122.2011.-NADPH oxidase p22phox subunit is responsible for the production of reactive oxygen species in the vascular tissue. The C242T polymorphism in the p22phox gene has been associated with diverse coronary artery disease phenotypes, but the findings about the protective or harmful effects of the T allele are still controversial. Our main aim was to assess the effect of p22phox C242T genotypes on arterial stiffness, a predictor of late morbidity and mortality, in individuals from the general population. We randomly selected 1,178 individuals from the general population of Vitoria City, Brazil. Genotypes for the C242T polymorphism were detected by PCR-RFLP, and pulse wave velocity (PWV) values were measured with a noninvasive automatic device Complior. p22phox and TNF-alpha gene expression were quantified by real-time PCR in human arterial mammary smooth muscle cells. In both the entire and nonhypertensive groups: individuals carrying the TT genotype had higher PWV values and higher risk for increased arterial stiffness [odds ratio (OR) 1.93, 95% confidence interval (CI) 1.27-2.92 and OR 1.78, 95% CI 1.07-2.95, respectively] compared with individuals carrying CC + CT genotypes, even after adjustment for covariates. No difference in the p22phox gene expression according C242T genotypes was observed. However, TNF-alpha gene expression was higher in cells from individual carrying the T allele, suggesting that this genetic marker is associated with functional phenotypes at the gene expression level. In conclusion, we suggest that p22phox C242T polymorphism is associated with arterial stiffness evaluated by PWV in the general population. This genetic association shed light on the understanding of the genetic modulation on vascular dysfunction mediated by NADPH oxidase.

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Nitric oxide (NO)-donors are pharmacologically active substances that in vivo or in vitro release NO. Their most common side effect is headache caused by cerebral vasodilatation. We previously demonstrated that the new NO-donor Ru(terpy)(bdq)NO](3+) (Terpy), synthesized in our laboratory, induces relaxation of rat aorta. This study aimed to verify the effect of Terpy and sodium nitroprusside (SNP) in basilar artery. We conducted vascular reactivity experiments on endothelium-denuded basilar rings. The concentrations of iron (Fe) and ruthenium (Ru) complex were analyzed in basilar artery lysates after incubation with NO donors by mass spectrometry. We also evaluated the NO released from SNP and Terpy by using confocal microscopy. Interestingly, Terpy did not induce relaxation of the basilar artery. SNP induced relaxation in a concentration-dependent way. NO donors cross the membrane of vascular smooth muscle and entered the cell. In spite of its permeability, Terpy did not release NO in the basilar artery. Otherwise, SNP released NO in the basilar artery cells cytoplasm. Taken together, our results demonstrate that the new NO donor (Terpy) failed to release NO and to induce relaxation in the basilar artery. The NO donor SNP induces vascular relaxation due to NO release in the vascular smooth muscle cells. (C) 2011 Elsevier B.V. All rights reserved.

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Vaquero AR, Ferreira NE, Omae SV, Rodrigues MV, Teixeira SK, Krieger JE, Pereira AC. Using gene-network landscape to dissect genotype effects of TCF7L2 genetic variant on diabetes and cardiovascular risk. Physiol Genomics 44: 903-914, 2012. First published August 7, 2012; doi:10.1152/physiolgenomics.00030.2012.-The single nucleotide polymorphism (SNP) within the TCF7L2 gene, rs7903146, is, to date, the most significant genetic marker associated with Type 2 diabetes mellitus (T2DM) risk. Nonetheless, its functional role in disease pathology is poorly understood. The aim of the present study was to investigate, in vascular smooth muscle cells from 92 patients undergoing aortocoronary bypass surgery, the contribution of this SNP in T2DM using expression levels and expression correlation comparison approaches, which were visually represented as gene interaction networks. Initially, the expression levels of 41 genes (seven TCF7L2 splice forms and 40 other T2DM relevant genes) were compared between rs7903146 wild-type (CC) and T2DM-risk (CT + TT) genotype groups. Next, we compared the expression correlation patterns of these 41 genes between groups to observe if the relationships between genes were different. Five TCF7L2 splice forms and nine genes showed significant expression differences between groups. RXR alpha gene was pinpointed as showing the most different expression correlation pattern with other genes. Therefore, T2DM risk alleles appear to be influencing TCF7L2 splice form's expression in vascular smooth muscle cells, and RXR alpha gene is pointed out as a treatment target candidate for risk reduction in individuals with high risk of developing T2DM, especially individuals harboring TCF7L2 risk genotypes.

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It has been previously shown that besides its classical role in blood pressure control the reninangiotensin system, mainly by action of angiotensin II on the AT1 receptor, exerts pro-inflammatory effects such as by inducing the production of cytokines. More recently, alternative pathways to this system were described, such as binding of angiotensin-(17) to receptor Mas, which was shown to counteract some of the effects evoked by activation of the angiotensin IIAT1 receptor axis. Here, by means of different molecular approaches we investigated the role of angiotensin-(17) in modulating inflammatory responses triggered in mouse peritoneal macrophages. Our results show that receptor Mas transcripts were up-regulated by eightfold in LPS-induced macrophages. Interestingly, macrophage stimulation with angiotensin-(17), following to LPS exposure, evoked an attenuation in expression of TNF-a and IL-6 pro-inflammatory cytokines; where this event was abolished when the receptor Mas selective antagonist A779 was also included. We then used heterologous expression of the receptor Mas in HEK293T cells to search for the molecular mechanisms underlying the angiotensin-(17)-mediated anti-inflammatory responses by a kinase array; what suggested the involvement of the Src kinase family. In LPS-induced macrophages, this finding was corroborated using the PP2 compound, a specific Src kinase inhibitor; and also by Western blotting when we observed that Ang-(17) attenuated the phosphorylation levels of Lyn, a member of the Src kinase family. Our findings bring evidence for an anti-inflammatory role for angiotensin-(17) at the cellular level, as well as show that its probable mechanism of action includes the modulation of Src kinases activities. J. Cell. Physiol. 227: 21172122, 2012. (C) 2011 Wiley Periodicals, Inc.

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A decrease in the number of cardiovascular events in patients with rheumatoid arthritis or psoriasis treated with methotrexate (MTX) has been observed in the literature. The aim of this study was to test whether MTX could promote anti-inflammatory effects and reduce the atherosclerotic lesions in rabbits with atherosclerosis induced by cholesterol feeding. Twenty male New Zealand rabbits were fed a 1% cholesterol diet for 60 days. Starting from day 30 of cholesterol feeding, 10 animals were treated with 4 weekly intravenous injections of MTX (4 mg/kg) and 10 with 4 weekly saline solution injections for 30 days. MTX reduced the size of the lesion areas of cholesterol-fed animals by 75% and intima-media ratio 2- fold. The drug inhibited macrophage migration into the intima by 50% and the presence of apoptotic cells by 84% but did not inhibit the intimal proliferation of smooth muscle cells. MTX treatment also diminished the positive staining area of metalloproteinase 9 in the intima, which is probably beneficial. In the tumor necrosis factor-alpha-treated human umbilical vein endothelial cell line, incubation with MTX led to downregulation of 5 pro-inflammatory genes, TNF-alpha, VAP-1, IL-1 beta, CXCL2, and TLR2, and upregulation of the antiinflammatory TGF-beta 1 gene, thus showing endothelium-protective properties. In conclusion, MTX showed direct in vivo anti-atherosclerotic action and may have potential in the treatment of this disorder.

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beta-Adrenoceptor (beta-AR)-mediated relaxation plays an important role in the regulation of vascular tone. beta-AR-mediated vascular relaxation is reduced in various disease states and aging. We hypothesized that beta-AR-mediated vasodilatation is impaired in DOCA-salt hypertension due to alterations in the cAMP pathway. beta-AR-mediated relaxation was determined in small mesenteric arteries from DOCA-salt hypertensive and control uninephrectomized (Uni) rats. To exclude nitric oxide (NO) and cyclooxygenase (COX) pathways, relaxation responses were determined in the presence of L-NNA and indomethacin, NO synthase inhibitor and COX inhibitors, respectively. Isoprenaline (ISO)-induced relaxation was reduced in arteries from DOCA-salt compared to Uni rats. Protein kinase A (PKA) inhibitors (H89 or Rp-cAMPS) or adenylyl cyclase inhibitor (SQ22536) did not abolish the difference in ISO-induced relaxation between the groups. Forskolin (adenylyl cyclase activator)-induced relaxation was similar between the groups. The inhibition of IKCa/SKCa channels (TRAM-34 plus UCL1684) or BKCa channels (iberiotoxin) reduced ISO-induced relaxation only in Uni rats and abolished the relaxation differences between the groups. The expression of SKCa channel was decreased in DOCA-salt arteries. The expression of BKCa channel a subunit was increased whereas the expression of BKCa channel p subunit was decreased in DOCA-salt arteries. The expression of receptor for activated C kinase 1 (RACK1), which is a binding protein for BKG, channel and negatively modulates its activity, was increased in DOCA-salt arteries. These results suggest that the impairment of beta-AR-mediated relaxation in DOCA-salt mesenteric arteries may be attributable to altered IKCa/SKCa and/or BKCa channels activities rather than cAMP/PKA pathway. Impaired beta-AR-stimulated BKCa channel activity may be due to the imbalance between its subunit expressions and RACK1 upregulation. (C) 2012 Elsevier Ltd. All rights reserved.

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Previous studies have shown that particulate matter (PM) compromise birth weight and placental morphology. We hypothesized that exposing mice to ambient PM would affect umbilical cord (UC) morphology. To test this, mice were kept in paired open-top exposure chambers at the same location and ambient conditions but, in one chamber, the air was filtered (F) and, in the other, it was not (NF). UCs were analysed stereologically and by immunohistochemistry to localize isoprostane and endothelin receptors. The cords of mice from NF chambers were smaller in volume due to loss of mucoid connective tissue and decrease in volume of collagen. These structural changes and in umbilical vessels were associated with greater volumes of regions immunostained for isoprostane, ETAR and ETBR. Findings indicate that the adverse effects of PM on birth weight may be mediated in part by alterations in UC structure or imbalances in the endogenous regulators of vascular tone and oxidative stress. (C) 2012 Elsevier Inc. All rights reserved.

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Background: Post-rest contraction (PRC) of cardiac muscle provides indirect information about the intracellular calcium handling. Objective: Our aim was to study the behavior of PRC, and its underlying mechanisms, in rats with myocardial infarction. Methods: Six weeks after coronary occlusion, the contractility of papillary muscles (PM) obtained from sham-operated (C, n = 17), moderate infarcted (MMI, n = 10) and large infarcted (LMI, n = 14) rats was evaluated, following rest intervals of 10 to 60 seconds before and after incubation with lithium chloride (Li+) substituting sodium chloride or ryanodine (Ry). Protein expression of SR Ca(2+)-ATPase (SERCA2), Na+/Ca2+ exchanger (NCX), phospholamban (PLB) and phospho-Ser(16)-PLB were analyzed by Western blotting. Results: MMI exhibited reduced PRC potentiation when compared to C. Opposing the normal potentiation for C, post-rest decays of force were observed in LMI muscles. In addition, Ry blocked PRC decay or potentiation observed in LMI and C; Li+ inhibited NCX and converted PRC decay to potentiation in LMI. Although MMI and LMI presented decreased SERCA2 (72 +/- 7% and 47 +/- 9% of Control, respectively) and phospho-Ser(16)-PLB (75 +/- 5% and 46 +/- 11%, respectively) protein expression, overexpression of NCX (175 +/- 20%) was only observed in LMI muscles. Conclusion: Our results showed, for the first time ever, that myocardial remodeling after MI in rats may change the regular potentiation to post-rest decay by affecting myocyte Ca(2+) handling proteins. (Arq Bras Cardiol 2012;98(3):243-251)

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We have cloned and characterized for the first time an allograft inflammatory factor 1 (Sn-AIF-1) from the Antarctic sea urchin. We report the cloning of Sn-AIF-1 cDNA and the characterization of its expression in coelomocytes after a bacterial challenge. The cDNA Sn-AIF-1 has a size of 608 bp and encodes a polypeptide of 151 aa. The deduced amino acid sequence has a putative size of 17.430 Da, an isoelectric point of 4.92, and shows 2 elongation factor handlike motifs that normally bind calcium ions. BLAST analysis revealed close matches with other known AIF-1. The deduced amino acid sequence of Sn-AIF-1 showed high homology with AIF-1 in vertebrates such as fish, mice, and humans; and in the case of invertebrates, the major degree of identity (55%) was with a predicted sequence of the purple sea urchin AIF-1, and 52% corresponded to a sponge. Expression of Sn-AIF-1 mRNA was analyzed by qPCR. Sn-AIF-1 mRNA expression was measured from coelomocytes after a bacterial challenge using RT-PCR and revealed that the gene was upregulated after 24 h. Sn-AIF-1 could participate in the inflammatory response, particularly in the activation of coelomocytes and their survival.

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Strongyloidiasis is an intestinal parasitosis with an obligatory pulmonary cycle. A Th2-type immune response is induced and amplifies the cellular response through the secretion of inflammatory mediators. Although this response has been described as being similar to asthma, airway remodeling during pulmonary migration of larvae has not yet been established. The aim of this study was to identify the occurrence of airway remodeling during Strongyloides venezuelensis (S. v.) infection and to determine the ability of dexamethasone treatment to interfere with the mechanisms involved in this process. Rats were inoculated with 9,000 S. v. larvae, treated with dexamethasone (2 mg/kg) and killed at 1, 3, 5, 7, 14 and 21 days. Morphological and morphometric analyzes with routine stains and immunohistochemistry were conducted, and some inflammatory mediators were evaluated using ELISA. Goblet cell hyperplasia and increased bronchiolar thickness, characterized by edema, neovascularization, inflammatory infiltrate, collagen deposition and enlargement of the smooth muscle cell layer were observed. VEGF, IL1-beta and IL-4 levels were elevated throughout the course of the infection. The morphological findings and the immunomodulatory response to the infection were drastically reduced in dexamethasone-treated rats. The pulmonary migration of S. venezuelensis larvae produced a transitory, but significant amount of airway remodeling with a slight residual bronchiolar fibrosis. The exact mechanisms involved in this process require further study. (C) 2012 Elsevier Ireland Ltd. All rights reserved.

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Breast cancer is the most common cause of cancer mortality among women worldwide. Among the several factors associated with breast cancer development, angiogenesis plays an essential role and has currently emerged as a potential diagnostic, prognostic and therapeutic target. Protease-activated receptor 1 (PAR1) and fibroblast growth factor receptor 1 (FGFR1) have important activities in tumor angiogenesis and progression. The aim of this study was to investigate the prognostic significance of these two receptors, hypothesising significant correlations between receptor expression in tumor angiogenesis and clinicopathological parameters customarily used in breast cancer prognosis and prediction. Formalin-fixed and paraffin-embedded samples of ductal invasive breast carcinomas were used to analyze the expression of PAR1 and FGFR1, in the tumor cells as well as in the tumor stroma, and further determine intratumoral microvessel density (iMVD) to quantify intratumoral angiogenesis. Correlations between PAR1 and FGFR1 expression in tumor cells and stroma, iMVD and several clinicopathological parameters and molecular markers used in breast cancer diagnosis have been addressed. The correlation between PAR1 and FGFR1 suggests an association of the two receptors with a more aggressive breast cancer phenotype and, consequently, a potential role during tumor progression. The results reported in the present study also emphasize the importance of microenvironmental factors in tumor progression, while precluding the positive association between iMVD and breast cancer aggressiveness.

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Background Airway inflammation in asthma involves innate immune responses. Toll-like receptors (TLRs) and thymic stromal lymphopoietin (TSLP) are thought to be involved in airway inflammation, but their expression in asthmatics both large and small airways has not been investigated. Objective To analyse the expression of TLR2, TLR3, TLR4 and TSLP in large and small airways of asthmatics and compare their expression in smoking and non-smoking asthmatics; to investigate whether TLR expression is associated with eosinophilic or neutrophilic airway inflammation and with Mycoplasma pneumoniae and Chlamydophila pneumoniae infection. Methods Using immunohistochemistry and image analysis, we investigated TLR2, TLR3, TLR4 and TSLP expression in large and small airways of 24 victims of fatal asthma, FA, (13 non-smokers, 11 smokers) and nine deceased control subjects (DCtrl). TLRs were also measured in 18 mild asthmatics (MA) and 12 healthy controls (HCtrl). M. pneumoniae and C. pneumoniae in autopsy lung tissue were analysed using real-time polymerase chain reaction. Airway eosinophils and neutrophils were measured in all subjects. Results Fatal asthma patients had higher TLR2 in the epithelial and outer layers of large and small airways compared with DCtrls. Smoking asthmatics had lower TLR2 levels in the inner and outer layers of the small airways than non-smoking asthmatics. TSLP was increased in the epithelial and outer layers of the large airways of FA. FA patients had greater TLR3 expression in the outer layer of large airways and greater TLR4 expression in the outer layer of small airways. Eosinophilic airway inflammation was associated with TLR expression in the epithelium of FA. No bacterial DNA was detected in FA or DCtrls. MA and HCtrls had only a small difference in TLR3 expression. Conclusions and Clinical Relevance Increased expression of TLR 2, 3 and 4 and TSLP in fatal asthma may contribute to the acute inflammation surrounding asthma deaths.

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The development of atherosclerosis and the inflammatory response were investigated in LDLr-KO mice on three high-fat diets (40% energy as fat) for 16 weeks: trans (TRANS), saturated (SAFA) or omega-6 polyunsaturated (PUFA) fats. The following parameters were measured: plasma lipids, aortic root total cholesterol (TC), lesion area (Oil Red-O), ABCA1 content and macrophage infiltration (immunohistochemistry), collagen content (Picrosirius-red) and co-localization of ABCA1 and macrophage (confocal microscopy) besides the plasma inflammatory markers (IL-6, TNF-alpha) and the macrophage inflammatory response to lipopolysaccharide from Escherichia coli (LPS). As expected, plasma TC and TG concentrations were lower on the PUFA diet than on TRANS or SAFA diets. Aortic intima macrophage infiltration, ABCA1 content, and lesion area on PUFA group were lower compared to TRANS and SAFA groups. Macrophages and ABCA1 markers did not co-localize in the atherosclerotic plaque, suggesting that different cell types were responsible for the ABCA1 expression in plaques. Compared to PUFA, TRANS and SAFA presented higher collagen content and necrotic cores in atherosclerotic plaques. In the artery wall, TC was lower on PUFA compared to TRANS group; free cholesterol was lower on PUFA compared to TRANS and SAFA; cholesteryl ester concentration did not vary amongst the groups. Plasma TNF-alpha concentration on PUFA and TRANS-fed mice was higher compared to SAFA. No difference was observed in IL-6 concentration amongst groups. Regarding the macrophage inflammatory response to LPS, TRANS and PUFA presented higher culture medium concentrations of IL-6 and TNF-alpha as compared to SAFA. The PUFA group showed the lowest amount of the anti-inflammatory marker IL-10 compared to TRANS and SAFA groups. In conclusion, PUFA intake prevented atherogenesis, even in a pro-inflammatory condition. (c) 2012 Elsevier Ireland Ltd. All rights reserved.