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Systemic sclerosis (SSc) is a connective tissue disease characterised by exaggerated collagen deposition in the skin and visceral organs. Adenosine A2A receptor stimulation (A2Ar) promotes dermal fibrosis, while the cannabinoid system modulates fibrogenesis in vitro and in animal models of SSc. Moreover, evidence in central nervous system suggests that A2A and cannabinoid (CB1) receptors may physically and functionally interact. On this basis, we investigated A2Ar expression and function in modulating collagen biosynthesis from SSc dermal fibroblasts and analysed the cross-talk with cannabinoid receptors. In sclerodermic cells, A2Ar expression (RT-PCR, Western blotting) was evaluated together with the effects of A2A agonists and/or antagonists on collagen biosynthesis (EIA, Western blotting). Putative physical and functional interactions between the A2A and cannabinoid receptors were respectively assessed by co-immuno-precipitation and co-incubating the cells with the unselective cannabinoid agonist WIN55,212-2, and the selective A2A antagonist ZM-241385. In SSc fibroblasts, (1) the A2Ar is overexpressed and its occupancy with the selective agonist CGS-21680 increases collagen production, myofibroblast trans-differentiation, and ERK-1/2 phosphorylation; (2) the A2Ar forms an heteromer with the cannabinoid CB1 receptor; and (3) unselective cannabinoid receptor stimulation with a per se ineffective dose of WIN55,212-2, results in a marked anti-fibrotic effect after A2Ar blockage. In conclusion, A2Ar stimulation induces a pro-fibrotic phenotype in SSc dermal fibroblasts, either directly, and indirectly, by activating the CB1 cannabinoid receptor. These findings increase our knowledge of the pathophysiology of sclerodermic fibrosis also further suggesting a new therapeutic approach to the disease.

The association between levels of circulating endothelial progenitor cells (EPCs) and heart transplant recipients (HTX) with cardiac allograft vasculopathy (CAV) is under debate. The chemokine receptor CXCR4 plays an important role in the mobilization of progenitor cells and is implicated in pathological conditions, including cardiovascular disease. This study aims to evaluate the association between EPCs and CXCR4-positive cells in HTX patients. Peripheral blood mononuclear cells (PBMCs) from 34 HTX patients and 25 control participants were analyzed by flow cytometry for CXCR4-positive cells and EPCs. Endothelial progenitor cells were defined by the expression of a range of hematopoietic and endothelial lineage markers in different combinations. The ability to form endothelial cell colonies in vitro was also assessed by colony-forming unit (CFU) assay. Phenotypic analysis of EPCs by flow cytometry revealed similar levels in HTX patients compared to controls. In addition, no difference was observed between levels of EPCs or CFU number in patients with and without CAV. By contrast, CFU assay revealed a reduced number of CFUs in HTX patients compared to controls (3.3% ± 0.95 and 13.3% ± 4.5%, respectively, P = 0.014). Likewise, levels of CXCR4-positive cells were significantly reduced (15.9 ± 1.4 in patients vs 24.8 ± 3.3% in controls, P < 0.01), negatively correlated with Framingham risk score (rho = -0.4, P = 0.02) and the number of risk factors (rho = -0.3, P = 0.049). Levels of CXCR4-positive cells were also correlated with CFU number (r = 0.65, P = 0.0005). These findings further develop our understanding of the role of EPCs and endothelial CFUs in cardiovascular disease, in addition to highlighting the potential importance of CXCR4 in heart transplantation.

Objectives: Evidence exists that the pleiotropic properties of the hydroxy-methyl-glutaryl Coenzyme A reductase inhibitors (statins) are not restricted to the cardiovascular system, as they can also favorably affect the joints, with intriguing implications for the treatment of many rheumatic diseases. In the view of the increasing interest on this topic, we here review the current state of the art., Methods: The PubMed database was searched for articles published between 1966 and 2010 for key words referring to statins and joint diseases. All relevant English-written articles were reviewed., Results: Many pivotal studies clearly demonstrated that HMG-CoA reductase inhibitors exert a wide spectrum of beneficial effects on the 3 main compartments of the joint, ie, the synovium, the cartilage, and the subchondral bone. Such (1) anti-inflammatory, (2) immunomodulating, and (3) anabolic effects strongly support a potential role of these drugs in the treatment and/or the prevention of the most important chronic joint diseases. However, although the majority of the in vivo studies with statins on animal models of inflammatory and degenerative joint diseases showed a marked protective activity substantially confirming the in vitro experiments, data arising from clinical trials are less probative and more conflicting., Conclusions: Statins display multiple joint-protective effects. Since oral administration of statins could result in a relatively low drug bioavailability to the joints, alternative routes of administration of the drug (transdermal, intra-articular) and/or specific delivery systems should be developed to establish the entire therapeutic potential of statins in this clinical setting., (Copyright © 2011 Elsevier Inc. All rights reserved.)

Raynaud's phenomenon, categorized as primary and secondary when occurring isolated or in association with an underlying disease, respectively, is a paroxysmal and recurrent acral ischemia resulting from an abnormal arterial vasospastic response to cold or emotional stress. The key issue in the pathogenesis of Raynaud's phenomenon is presumed to be a dysregulation in the mechanisms of vascular motility resulting in an imbalance between vasodilatation and vasoconstriction. Homocysteine, a non-protein forming sulphured amino acid proposed as an independent risk factor for atherothrombosis in the general population, clearly demonstrated to produce vascular damage through mechanisms also including endothelial injury and modifications in circulating mediators of vasomotion. The rationale for homocysteine involvement in the pathogenesis of Raynaud's phenomenon led some authors to investigate the possible association between mild hyperhomocysteinemia and such a vascular disturbance, particularly in the course of connective tissue disease. Here we review data regarding this putative association and the supposed mechanisms involved, also discussing the emblematic case of a patient with new-onset severe Raynaud's phenomenon and markedly elevated homocysteinemia., (Copyright 2009 Elsevier B.V. All rights reserved.)

The arrhythmogenicity of anti-Ro/SSA antibodies for the foetal heart and their crucial role in the development of congenital heart block is now well established, representing a paradigmatic model of passively acquired autoimmunity. Recently, intriguing data suggest that also the adult heart may represent a possible target of anti-Ro/SSA antibody-mediated autoimmune injury. The prolongation of the QTc interval, possibly resulting from a direct inhibitory interaction between the anti-Ro/SSA antibodies and the potassium current I(Kr) in the heart seems the abnormality more frequently observed in adults with anti-Ro/SSA-positive CTD. Although the possibility that anti-Ro/SSA positivity may be considered a risk factor for arrhythmic sudden death in adults has not been demonstrated as yet, preliminary data suggest a relationship among anti-Ro/SSA antibodies, QTc prolongation, and the prevalence of ventricular arrhythmias, also life threatening, in adult patients.

Background: Pathogenic avian influenza virus (H5N1) has the potential to cause a major global pandemic in humans. Safe and effective vaccines that induce immunologic memory and broad heterotypic response are needed., Methods and Findings: Healthy adults aged 18-60 and > 60 years (n = 313 and n = 173, respectively) were randomized (1:1) to receive two primary and one booster injection of 7.5 microg or 15 microg doses of a subunit MF59-adjuvanted H5N1 (A/Vietnam/1194/2004) (clade 1) vaccine. Safety was monitored until 6 months after booster. Immunogenicity was assessed by hemagglutination inhibition (HI), single radial hemolysis (SRH) and microneutralization assays (MN). Mild injection-site pain was the most common adverse reaction. No serious adverse events relating to the vaccine were reported. The humoral immune responses to 7.5 microg and 15 microg doses were comparable. The rates for seroprotection (HI>40; SRH>25 mm(2); MN > or = 40) after the primary vaccination ranged 72-87%. Six months after primary vaccination with the 7.5 microg dose, 18% and 21% of non-elderly and elderly adults were seroprotected; rates increased to 90% and 84%, respectively, after the booster vaccination. In the 15 microg group, seroprotection rates among non-elderly and elderly adults increased from 25% and 62% after primary vaccination to 92% and 88% after booster vaccination, respectively. A heterologous immune response to the H5N1/turkey/Turkey/05 strain was elicited after second and booster vaccinations., Conclusions: Both formulations of MF59-adjuvanted influenza H5N1 vaccine were well tolerated. The European Union requirement for licensure for pre-pandemic vaccines was met by the lower dose tested. The presence of cross-reactive antibodies to a clade 2 heterologous strain demonstrates that this vaccine may be appropriate for pre-pandemic programs., Trial Registration: (ClinicalTrials.gov) NCT00311480.

Objective: Reports suggest that infliximab (IFX) may be associated with life-threatening tachyarrhythmias and bradyarrhythmias. We evaluated the prevalence of cardiac rhythm disorders during acute infusion of IFX in a prospective, single-blind, placebo-controlled crossover study of patients with chronic arthritis. Effects of the drug on measures of arrhythmia risk such as QT interval and heart rate variability (HRV) were evaluated., Methods: Seventy-five patients with spondyloarthritis (SpA; n=55) or rheumatoid arthritis (RA) underwent an ambulatory 12-channel electrocardiogram (ECG) recording to monitor cardiac arrhythmias, QT interval, and HRV during the infusion of IFX and saline (placebo)., Results: The occurrence of both tachyarrhythmias and bradyarrhythmias was not statistically different during IFX or placebo infusion. During IFX infusion, new-onset ventricular tachyarrhythmias had an 8% incidence (2.7% with placebo; OR 3.17, 95% CI 0.61-16.26) and were more severe. In these patients, mainly with RA, baseline-corrected QT interval and HRV values were significantly prolonged and depressed, respectively, in comparison with subjects without such arrhythmias. IFX acutely produced a significant shift toward a relative vagal prevalence without affecting QT interval measurements., Conclusion: New-onset cardiac arrhythmias, particularly ventricular tachyarrhythmias, developed during IFX infusion, but their incidence did not achieve statistical significance. We identified some specific risk factors possibly characteristic of the small subset of patients with a higher risk for ventricular arrhythmias. The acute effects of IFX on autonomic balance may substantiate the role of the complex interaction between autonomic nervous system and inflammation during chronic arthritis.

Human type B synoviocytes are involved in joint injury during rheumatic diseases by producing inflammatory mediators such as interleukin-6 (IL-6). The increased level of purine and pirimidine nucleotides in the synovial fluid of rheumatoid arthritis (RA) patients could activate the large family of P2 receptors. Thus, we investigated the presence of P2 receptors in human type B synoviocytes from rheumatoid joints, also evaluating whether the P2X7 receptor is involved in IL-6 release. Reverse transcriptase polymerase chain reaction analysis revealed messenger ribonucleic acid (mRNA) expression for the P2X1, P2X2, P2X4, P2X5, P2X6, P2X7, P2Y1, P2Y4, P2Y11, P2Y12, P2Y13, and P2Y14 but not the P2X3, P2Y2, and P2Y6 receptors. The expression of the P2X7 receptor was confirmed by Western blot analysis. Adenosine triphosphate (ATP) and the P2X7 receptor agonist 2'-3'-O-(4-benzoylbenzoyl)ATP (BzATP) triggered an increase in intracellular calcium, thereby suggesting the expression of functional P2 receptors, including the P2X7 receptor. Moreover, BzATP treatment upregulated both IL-6 mRNA and protein expression. Synoviocytes spontaneously released low quantities of IL-6; the incubation with BzATP induced the release of larger amounts of the cytokine, and such a release was blunted by the P2X7 antagonist oxidized ATP. The selective P2X1 and P2X3 receptor agonist alpha,beta-methylene ATP did not affect IL-6 release. Finally, BzATP failed to induce a significant uptake of the large-molecule YO-PRO, thus suggesting the lack of pore formation after P2X7 receptor stimulation. In conclusion, among the different P2 receptors expressed on human RA type B synoviocytes, the P2X7 receptor may modulate IL-6 release but not inducing changes in cell membrane permeability.

Cardiac arrhythmias, including conduction defects and tach- yarrhythmias, represent an important source of morbidity and mortality in industrialized countries. Among the different pathophysiological mechanisms involved in the arrhythmogenesis, an inappropriate activation of the immune system represents a field of recent increasing interest. In fact, a large amount of studies suggest that specific autoantibody may be significantly involved in the pathogenesis of cardiac arrhythmias not only in the course of systemic autoimmune disease, but also in a number of rhythm disorders currently classified as "idiopathic." Although the strongest evidence concerns the relationship between anti-Ro/SSA antibodies and the development of congenital heart block in foetus and newborn, other specific autoantibodies demonstrated the aptitude to affect directly the myocardial tissue, thus producing interference in its bioelectric activity thereby leading to rhythm disorders, also life-threatening. The identification of an immunological autoantibody-mediated mechanism opens new perspectives in the treatment and prevention of cardiac arrhythmias in such patients, including the use of immunosuppressive agents and/or the removal of autoantibodies by immuno-adsorption technique.

A previous study of electrocardiography at rest showed that anti-Ro/SSA-positive patients with connective tissue disease (CTD) frequently had corrected QT (QTc) interval prolongation. Because QTc interval prolongation is a definite risk factor for arrhythmic sudden death in the general population, a 24-hour electrocardiographic monitoring study was performed to investigate the possible relation between QTc interval prolongation and incidence of ventricular arrhythmias as a possible expression of immunomediated electric instability of the myocardium in anti-Ro/SSA-positive patients with CTD. The study population consisted of 46 patients with CTD; 26 anti-Ro/SSA-positive and 20 anti-Ro/SSA-negative (control group) patients (Sjögren's syndrome, 9 and 3 patients; systemic lupus erythematosus, 4 and 9 patients; systemic sclerosis, 2 and 4 patients; undifferentiated CTD, 8 and 1 patients; mixed CTD, 2 and 2 patients, and polymyositis/dermatomyositis, 1 and 1 patient, respectively). All patients underwent ambulatory Holter electrocardiography to obtain 24-hour monitoring of the QTc interval and ventricular arrhythmias. With respect to the control group, anti-Ro/SSA-positive patients with CTD (1) commonly showed QTc interval prolongation (46% vs 5%), and this abnormality, when present, persisted for the 24 hours (global mean 24-hour QTc interval 440.5+/-23.4 vs 418.2+/-13.2 ms); (2) had a higher incidence of complex ventricular arrhythmias (i.e., Lown classes 2 to 5, 50% vs 10%) also in the absence of detectable cardiac abnormalities; and (3) in patients with CTD, there is a direct relation between global mean 24-hour QTc interval and ventricular arrhythmic load independently of age and disease duration. In conclusion, anti-Ro/SSA-positive patients with CTD seemed to have a particularly high risk of developing ventricular arrhythmias. The risk appeared related mainly to abnormalities in ventricular electrophysiologic characteristics emerging in the clinical setting as QTc interval prolongation.

Hyperhomocysteinemia is independently associated with the development of coronary, cerebral and peripheral vascular disease and deep-vein thrombosis in the general population. The evidence that cardiovascular involvement is particularly frequent and advanced in patients affected with several autoimmune diseases (AD), in which hyperhomocysteinemia represent a common finding, led to an intensive investigation on homocysteine (Hcy) as a putative risk factor for the development of cardiovascular disease in such subjects. Indeed, recent data intriguingly expanded the spectrum of the possible pathogenetic implications for hyperhomocysteinemia in the course of AD. In fact, a bi-directional link seems to connect Hcy and the immuno-inflammatory activation characterizing AD, in which immuno-inflammatory activation may contribute to Hcy increase, and Hcy, in its turn, may act as a pro-inflammatory and immuno-stimulating molecule putatively cooperating to the injury of the disease-specific target organs, at least in rheumatoid arthritis and inflammatory bowel disease. Moreover, Hcy may be also a trigger of autoimmune reactions through its capability to bind and structurally modify specific proteins, then resulting in neoantigens formation potentially relevant either in the onset of specific AD and in the progression of the associated cardiovascular damage. More investigation is necessary to fully define the clinical relevance of such phenomena.

Cardiovascular involvement is common in connective tissue diseases (CTD), with relevant implications in terms of morbidity and mortality. Rhythm disturbances, i.e. conduction defects and tachyarrhythmias, represent a frequent clinical manifestation of CTD-associated cardiovascular damage and a possible cause of sudden death. The underlying arrhythmogenic mechanisms are probably multiple and intriguing, even though the myocardial fibrosis frequently observed at the pathological examination seems to play a pivotal role. Myocardial fibrosis is produced directly by inflammatory processes, or indirectly as a consequence of coronary artery occlusive disease, and it may affect the conduction system also representing the pathological substrate for reentry circles. An overview of CTD-associated cardiac rhythm disturbances is here provided. Among CTD-associated rhythm disorders, congenital heart block (CHB), which represents the main feature of neonatal lupus, a rare syndrome related to the transplacental passage of autoantibodies from anti-Ro/SSA-positive mother to their newborns, seems to acknowledge a peculiar mechanism of disease possibly dependent on a direct arrhythmogenicity of anti-Ro/SSA antibodies. Moreover, new anti-Ro/SSA-associated EKG abnormalities have been recently described in children (sinus bradycardia and corrected QT (QTc) interval prolongation) as well as in adults (QTc interval prolongation).

Peripheral blood mononuclear cells of chronic heart failure (CHF) patients produce great amounts of pro-inflammatory cytokines, indicating that circulating cells are activated and could mirror changes occurring in inflammatory cells infiltrating the failing heart. Adenosine is a regulatory metabolite acting through four membrane receptors that are linked to adenylyl cyclase: activation of the A2A receptor subtype has been reported to inhibit cytokine release. Changes of the adenosinergic system may play a role in CHF development. Here we report an increase of A2A receptor expression, density, and coupling to adenylyl cyclase in blood circulating cells of CHF patients. A2A receptor up-regulation was also found in the explanted hearts of these patients, suggesting that changes of peripheral adenosine receptors mirror changes occurring in the disease target organ. In a cohort of patients followed longitudinally after heart transplantation, alterations of peripheral A2A adenosine receptor progressively normalized to control values within 6 months, suggesting that improvement of cardiac performance is accompanied by progressive restoration of a normal adenosinergic system. These results validate the importance of the A2A receptor in human diseases characterized by a marked inflammatory/immune component and suggest that the evaluation of this receptor in peripheral blood cells may be useful for monitoring hemodynamic changes and the efficacy of pharmacological and non-pharmacological treatments in CHF patients.

Pulse ischemia-dependent submaximal increase in adenosine levels in plasma and in the interstitium is believed to mediate the phenomenon of ischemic preconditioning of the heart, by the interaction with the specific A1 and A3 receptors on myocytes. The aim of the study was to evaluate the effects of chronic oral treatment with dipyridamole (75 mg twice a day for 5 days) in coronary artery disease (CAD) patients with positive echocardiographic stress test with high-dose dipyridamole (DET). We evaluated positivity to DET, adenosine plasma levels in 12 patients treated with dipyridamole in comparison to eight patients treated with placebo. After oral administration of dipyridamole we observed a significant reduction in the number of patients positive to DET (5/12; P=0.02), a pulse increase in adenosine plasma levels (from 220+/-55 to 450+/-70 nmol/l), without any significant haemodynamic effects. Our results suggest that dipyridamole, administered orally at a low dose, but sufficient to increase adenosine plasma level, was able to prevent myocardial ischemia induced by high-dose dipyridamole echo-stress test in CAD patients.