Atheroprotective effects of methotrexate on reverse cholesterol transport proteins and foam cell transformation in human THP-1 monocyte/macrophages

Targeting Inflammation to Prevent Cardiovascular Disease in Chronic Rheumatic Diseases: Myth or Reality?

Evidence for increased risk of cardiovascular morbidity and mortality in chronic inflammatory rheumatic diseases has accumulated during the last years. Traditional cardiovascular risk factors contribute in part to the excess of cardiovascular risk in these patients and several mechanisms, including precocious acceleration of subclinical atherosclerotic damage, inflammation, and immune system deregulation factors, have been demonstrated to strictly interplay in the induction and progression of atherosclerosis. In this setting, chronic inflammation is a cornerstone of rheumatic disease pathogenesis and exerts also a pivotal role in all stages of atherosclerotic damage. The strict link between inflammation and atherosclerosis suggests that cardiovascular risk may be reduced by rheumatic disease activity control. There are data to suggest that biologic therapies, in particular TNFα antagonists, may improve surrogate markers of cardiovascular disease and reduce CV adverse outcome. Thus, abrogation of inflammation is considered an important outcome for achieving not only control of rheumatic disease, but also reduction of cardiovascular risk. However, the actual effect of anti-rheumatic therapies on atherosclerosis progression and CV outcome in these patients is rather uncertain due to great literature inconsistency. In this paper, we will summarize some of the main mechanisms linking the inflammatory pathogenic background underlying rheumatic diseases and the vascular damage observed in these patients, with a particular emphasis on the pathways targeted by currently available therapies. Moreover, we will analyze current evidence on the potential atheroprotective effects of these treatments on cardiovascular outcome pointing out still unresolved questions.

Cardiovascular effects of methotrexate in immune-mediated inflammatory diseases

The cardiovascular effects of disease-modifying antirheumatic drugs and particularly of methotrexate (MTX) are complex and frequently incorrectly understood, which might lead to the unjustified discontinuation of this treatment. MTX, 'the gold standard' and first line treatment in rheumatoid arthritis, psoriatic arthritis, and other immune-mediated inflammatory diseases, has been proven to decrease inflammation, improve cardiovascular risk factors, and reduce mortality. This is supported by both the mechanism of action, as well as a body of clinical data evidence. MTX's cardiovascular effects, although incompletely understood, are explained by its antiproliferative, immunosuppressive, anti-inflammatory, and antiatherogenic effects. Several clinical trials have shown that MTX is associated with improved endothelial function, slower atherosclerosis progression, decreased risk of major cardiovascular adverse events, and benefits on survival. Given its systemic cardiovascular effects, MTX could be regarded as an important therapeutic agent not only to control disease activity in rheumatic diseases, but also to reduce cardiovascular risk and mortality.

Repurposing existing drugs for cardiovascular risk management: a focus on methotrexate

About 20% of patients with a history of atherosclerotic cardiovascular disease will experience further cardiovascular events despite maximal pharmacological treatment with cardioprotective drugs. This highlights the presence of residual cardiovascular risk in a significant proportion of patients and the need for novel, more effective therapies. These therapies should ideally target different pathophysiological pathways involved in the onset and the progression of atherosclerosis, particularly the inflammatory and immune pathways. Methotrexate is a first-line disease-modifying antirheumatic drug that is widely used for the management of autoimmune and chronic inflammatory disorders. There is some in vitro and in vivo evidence that methotrexate might exert a unique combination of anti-inflammatory, blood pressure lowering, and vasculoprotective effects. Pending the results of large prospective studies investigating surrogate end-points as well as morbidity and mortality, repurposing methotrexate for cardiovascular risk management might represent a cost-effective strategy with immediate public health benefits. This review discusses the current challenges in the management of cardiovascular disease; the available evidence on the effects of methotrexate on inflammation, blood pressure, and surrogate markers of arterial function; suggestions for future research directions; and practical considerations with the use of methotrexate in this context.

Cardiovascular outcomes of patients with rheumatoid arthritis prescribed disease modifying anti-rheumatic drugs: a review

INTRODUCTION

Rheumatoid arthritis (RA) is associated with a heightened risk of cardiovascular disease (CVD), with both traditional CV risk factors and inflammation contributing to this risk.

AREAS COVERED

This review highlights the burden of CVD in RA and associated traditional CV risk factors, including the complexity of dyslipidemia in RA and the so-called 'lipid paradox.' Furthermore, the recognized RA-disease-specific factors associated with higher risk of CVD and the role of systemic inflammation in the pathogenesis of CVD in RA will be addressed. With the advent of biologic and targeted synthetic therapies in the treatment of RA, the effect of conventional and newer generation disease modifying anti-rheumatic therapies (DMARDs) on CV risk and associated risk factors will also be discussed.

EXPERT OPINION

Identifying the RA phenotype at greatest risk of CVD, understanding the interplay of increased traditional risk factors, common inflammatory processes and RA-specific factors, and personalized use of DMARDs according to disease phenotype and comorbidity to reduce this risk are key areas for future research.

Increased cardiovascular risk in rheumatoid arthritis: mechanisms and implications

Rheumatoid arthritis is a systemic autoimmune disease characterized by excess morbidity and mortality from cardiovascular disease. Mechanisms linking rheumatoid arthritis and cardiovascular disease include shared inflammatory mediators, post-translational modifications of peptides/proteins and subsequent immune responses, alterations in the composition and function of lipoproteins, increased oxidative stress, and endothelial dysfunction. Despite a growing understanding of these mechanisms and their complex interplay with conventional cardiovascular risk factors, optimal approaches of risk stratification, prevention, and treatment in the context of rheumatoid arthritis remain unknown. A multifaceted approach to reduce the burden posed by cardiovascular disease requires optimal management of traditional risk factors in addition to those intrinsic to rheumatoid arthritis such as increased disease activity. Treatments for rheumatoid arthritis seem to exert differential effects on cardiovascular risk as well as the mechanisms linking these conditions. More research is needed to establish whether preferential rheumatoid arthritis therapies exist in terms of prevention of cardiovascular disease. Ultimately, understanding the unique mechanisms for cardiovascular disease in rheumatoid arthritis will aid in risk stratification and the identification of novel targets for meaningful reduction of cardiovascular risk in this patient population.

Double trouble: psoriasis and cardiometabolic disorders

Psoriasis (PsO) is a chronic immune-mediated inflammatory skin disorder associated with numerous co-morbidities. This descriptive review focuses on the cardiometabolic co-morbidities of PsO with reference to the epidemiology and pathogenetic mechanisms linking PsO and cardiometabolic disease (CMD). Registry-based studies have shown PsO to be associated with an increased risk of cardiovascular morbidity and mortality. Factors linking PsO and CMD include: chronic inflammation, obesity, classic cardiovascular risk factors, and the effects of systemic therapy used to treat PsO. Chronic inflammation is associated with PsO itself, and with obesity. Adipose tissue is responsible for the secretion of various adipokines, which together with pro-inflammatory cytokines arising from the psoriatic plaque, contribute to the proinflammatory and pro-atherogenic environment. Systemic therapy aimed at decreasing inflammation has been shown to improve CMD in PsO. Screening for and treating CMD and initiating lifestyle modifications will remain the most important interventions until further data emerge regarding the effect of systemic therapy on CMD progression.

PreImplantation factor prevents atherosclerosis via its immunomodulatory effects without affecting serum lipids

PreImplantation factor (PIF) is a 15-amino acid peptide endogenously secreted by viable embryos, regulating/enabling maternal (host) acceptance/tolerance to the “invading” embryo (allograft) all-while preserving maternal immunity to fight infections. Such attributes make PIF a potential therapeutic agent for chronic inflammatory diseases. We investigated whether PIF’s immunomodulatory properties prevent progression of atherosclerosis in the hyper-cholesterolaemic ApoEdeficient murine model. Male, high-fat diet fed, ApoE-deficient (ApoE-/-) mice were administered either PBS, scrambled PIF (0.3–3 mg/kg) or PIF (0.3–3 mg/kg) for seven weeks. After treatment, PIF (3 mg/kg)-treated ApoE-/- mice displayed significantly reduced atherosclerosis lesion burden in the aortic sinus and aortic arch, without any effect on lipid profile. PIF also caused a significant reduction in infiltration of macrophages, decreased expression of pro-inflammatory adhesion molecules, cytokines and chemokines in the plaque, and reduced circulating IFN-γ levels. PIF preferentially binds to monocytes/neutrophils. In vitro, PIF attenuated monocyte migration (MCP-1-induced chemotaxis assay) and in vivo in LPS peritonitis model. Also PIF prevented leukocyte extravasation (peritonitis thioglycollate-induced model), demonstrating that PIF exerts its effect in part by modulation of monocyte function. Inhibition of the potassium channel KCNAB3 (Kv1.3) and of the insulin degrading enzyme (IDE) was demonstrated as potential mechanism of PIF’s immunomodulatory effects. In conclusion, PIF regulates/lowers inflammation and prevents atherosclerosis development without affecting circulating lipids. Overall our findings establish PIF as a strong immunomodulatory drug candidate for atherosclerosis therapy.

Supplementary Material to this article is available online at www.thrombosis-online.com.

Current and future therapies for addressing the effects of inflammation on HDL cholesterol metabolism

Cardiovascular disease (CVD) is a major cause of morbidity and mortality worldwide. Inflammatory processes arising from metabolic abnormalities are known to precipitate the development of CVD. Several metabolic and inflammatory markers have been proposed for predicting the progression of CVD, including high density lipoprotein cholesterol (HDL-C). For ~50 years, HDL-C has been considered as the atheroprotective 'good' cholesterol because of its strong inverse association with the progression of CVD. Thus, interventions to increase the concentration of HDL-C have been successfully tested in animals; however, clinical trials were unable to confirm the cardiovascular benefits of pharmaceutical interventions aimed at increasing HDL-C levels. Based on these data, the significance of HDL-C in the prevention of CVD has been called into question. Fundamental in vitro and animal studies suggest that HDL-C functionality, rather than HDL-C concentration, is important for the CVD-preventive qualities of HDL-C. Our current review of the literature positively demonstrates the negative impact of systemic and tissue (i.e. adipose tissue) inflammation in the healthy metabolism and function of HDL-C. Our survey indicates that HDL-C may be a good marker of adipose tissue health, independently of its atheroprotective associations. We summarize the current findings on the use of anti-inflammatory drugs to either prevent HDL-C clearance or improve the function and production of HDL-C particles. It is evident that the therapeutic agents currently available may not provide the optimal strategy for altering HDL-C metabolism and function, and thus, further research is required to supplement this mechanistic approach for preventing the progression of CVD.

LINKED ARTICLES

This article is part of a themed section on Targeting Inflammation to Reduce Cardiovascular Disease Risk. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.22/issuetoc and http://onlinelibrary.wiley.com/doi/10.1111/bcp.v82.4/issuetoc.

Methotrexate and anti-tumor necrosis factor treatment improves endothelial function in patients with inflammatory arthritis

Background

Inflammatory arthritis (IA), including rheumatoid arthritis (RA), ankylosing spondylitis (AS) and psoriatic arthritis (PsA), leads to increased cardiovascular disease occurrence probably due to atherosclerosis. One of the first stages in atherogenesis is endothelial dysfunction (ED). Therefore, we aimed to compare endothelial function (EF) in patients with IA, and to examine the effects of methotrexate (MTX) monotherapy and antitumor necrosis factor (anti-TNF) treatment with or without MTX comedication (anti-TNF ± MTX) on EF.

Methods

From the PSARA observational study, all patients with RA (n = 64), PsA (n = 29), and AS (n = 20) were evaluated for EF. In patients with ED at baseline (n = 40), we evaluated changes in the Reactive Hyperemic Index (RHI) after 6 weeks and 6 months of antirheumatic therapy.

Results

In IA patients with ED, RHI significantly improved after 6 weeks (p < 0.001) and 6 months (p < 0.001) of treatment, independent of changes in disease activity parameters. After 6 months, RHI had improved more in the MTX group than in the anti-TNF ± MTX group, and the difference remained statistically significant after adjustments for potential confounders. Among patients with active RA, AS, and PsA, those with AS appeared to have the worst endothelial function, although they were the youngest.

Conclusion

Treatment with MTX and anti-TNF ± MTX was associated with a relatively fast improvement of EF in IA patients with ED, independent of change in disease activity. Therefore, modes of action other than the anti-inflammatory effect may contribute to the EF improvement. After 6 months, the EF improvement was more pronounced in the MTX group than in the anti-TNF ± MTX group.

Trial registration

Clinicaltrials, NCT00902005. Registered on 13 May 2009.

Targeting inflammation to reduce cardiovascular disease risk: a realistic clinical prospect?

Data from basic science experiments is overwhelmingly supportive of the causal role of immune-inflammatory response(s) at the core of atherosclerosis, and therefore, the theoretical potential to manipulate the inflammatory response to prevent cardiovascular events. However, extrapolation to humans requires care and we still lack definitive evidence to show that interfering in immune-inflammatory processes may safely lessen clinical atherosclerosis. In this review, we discuss key therapeutic targets in the treatment of vascular inflammation, placing basic research in a wider clinical perspective, as well as identifying outstanding questions.

LINKED ARTICLES

This article is part of a themed section on Targeting Inflammation to Reduce Cardiovascular Disease Risk. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.22/issuetoc and http://onlinelibrary.wiley.com/doi/10.1111/bcp.v82.4/issuetoc.

Immune-inflammatory responses in atherosclerosis: Role of an adaptive immunity mainly driven by T and B cells

Adaptive immune response plays an important role in atherogenesis. In atherosclerosis, the proinflammatory immune response driven by Th1 is predominant but the anti-inflammatory response mediated mainly by regulatory T cells is also present. The role of Th2 and Th17 cells in atherogenesis is still debated. In the plaque, other T helper cells can be observed such as Th9 and Th22 but is little is known about their impact in atherosclerosis. Heterogeneity of CD4(+) T cell subsets presented in the plaque may suggest for plasticity of T cell that can switch the phenotype dependening on the local microenvironment and activating/blocking stimuli. Effector T cells are able to recognize self-antigens released by necrotic and apoptotic vascular cells and induce a humoral immune reaction. Tth cells resided in the germinal centers help B cells to switch the antibody class to the production of high-affinity antibodies. Humoral immunity is mediated by B cells that release antigen-specific antibodies. A variety of B cell subsets were found in human and murine atherosclerotic plaques. In mice, B1 cells could spontaneously produce atheroprotective natural IgM antibodies. Conventional B2 lymphocytes secrete either proatherogenic IgG, IgA, and IgE or atheroprotective IgG and IgM antibodies reactive with oxidation-specific epitopes on atherosclerosis-associated antigens. A small population of innate response activator (IRA) B cells, which is phenotypically intermediate between B1 and B2 cells, produces IgM but possesses proatherosclerotic properties. Finally, there is a minor subset of splenic regulatory B cells (Bregs) that protect against atherosclerotic inflammation through support of generation of Tregs and production of anti-inflammatory cytokines IL-10 and TGF-β and proapoptotic molecules.

HDL function and subclinical atherosclerosis in juvenile idiopathic arthritis

BACKGROUND

Increasing evidence suggests that inflammation adversely impacts the protective properties of high-density lipoproteins (HDL) and progression of atherosclerosis. The impact of early chronic inflammatory conditions on HDL function and vascular risk has not been well investigated.

METHODS

We compared measures of HDL particle distribution and functionality, in addition to measures of carotid intima-medial thickness (cIMT) in patients with juvenile idiopathic arthritis (JIA) and age matched controls.

RESULTS

JIA patients demonstrated lower levels of HDL cholesterol [47.0 (40.0, 56.0) vs. 56.0 (53.0, 61.0) mg/dL, P=0.04], total HDL [29.5 (27.9, 32.3) vs. 32.9 (31.6, 36.3) mg/dL, P=0.05] and large HDL [5.1 (3.7, 7.3) vs. 8.0 (6.7, 9.7) mg/dL, P=0.04] particles. In association JIA patients demonstrated greater cholesterol efflux mediated via ATP binding cassette A1 (ABCA1) [17.3% (12.8, 19.7) vs. 10.0% (5.8, 16.0), P=0.05] and less efflux mediated via ATP binding cassette G-1 (ABCG1) [3.2% (2.0, 3.9) vs. 4.8% (3.5, 5.8), P=0.01] and SR-B1 [6.9% (6.0, 8.4) vs. 9.1% (8.6, 10.2), P=0.002] compared with controls. Exposure of macrophages to serum from JIA patients resulted in a smaller increase in mRNA expression of ABCA1 (2.0±0.95 vs. 7.1±5.7 fold increase, P=0.01) and greater increases in expression of ABCG1 [1.4 (0.9, 1.5) vs. 0.8 (0.7, 1.1) fold increase, P=0.04] and SR-B1 (1.3±0.47 vs. 0.7±0.3 fold increase, P=0.001) compared with controls. Arylesterase (128.9±27.6 vs. 152.0±45.2 umoles/min/mL, P=0.04) activity and endothelial cell migration (491.2±68.9 vs. 634.2±227.4 cells/field, P=0.01) were less in JIA patients. No differences in cIMT were observed between JIA patients and controls.

CONCLUSIONS

The presence of JIA was associated with alterations in HDL particle distribution, cholesterol efflux and non-lipid transporting activities. The ultimate implication of these findings for cardiovascular risk requires further investigation.

Methotrexate-mediated activation of an AMPK-CREB-dependent pathway: a novel mechanism for vascular protection in chronic systemic inflammation

AIMS

Premature cardiovascular events complicate chronic inflammatory conditions. Low-dose weekly methotrexate (MTX), the most widely used disease-modifying drug for rheumatoid arthritis (RA), reduces disease-associated cardiovascular mortality. MTX increases intracellular accumulation of adenosine monophosphate (AMP) and 5-aminoimidazole-4-carboxamide ribonucleotide which activates AMP-activated protein kinase (AMPK). We hypothesised that MTX specifically protects the vascular endothelium against inflammatory injury via induction of AMPK-regulated protective genes.

METHODS/RESULTS

In the (NZW×BXSB)F1 murine model of inflammatory vasculopathy, MTX 1 mg/kg/week significantly reduced intramyocardial vasculopathy and attenuated end-organ damage. Studies of human umbilical vein endothelial cells (HUVEC) and arterial endothelial cells (HAEC) showed that therapeutically relevant concentrations of MTX phosphorylate AMPKα(Thr172), and induce cytoprotective genes including manganese superoxide dismutase (MnSOD) and haem oxygenase-1 (HO-1). These responses were preserved when HUVECs were pretreated with tumour necrosis factor-α to mimic dysfunctional endothelium. Furthermore, MTX protected against glucose deprivation-induced endothelial apoptosis. Mechanistically, MTX treatment led to cyclic AMP response element-binding protein (CREB)(Ser133) phosphorylation, while AMPK depletion attenuated this response and the induction of MnSOD and HO-1. CREB siRNA inhibited upregulation of both cytoprotective genes by MTX, while chromatin immunoprecipitation demonstrated CREB binding to the MnSOD promoter in MTX-treated EC. Likewise, treatment of (NZW×BXSB)F1 mice with MTX enhanced AMPKα(Thr172) phosphorylation and MnSOD, and reduced aortic intercellular adhesion molecule-1 expression.

CONCLUSIONS

These data suggest that MTX therapeutically conditions vascular endothelium via activation of AMPK-CREB. We propose that this mechanism contributes to the protection against cardiovascular events seen in patients with RA treated with MTX.

Effects of Methotrexate on Carotid Intima-media Thickness in Patients with Rheumatoid Arthritis

The purpose of this study was to evaluate the effects of rheumatoid arthritis (RA) and antirheumatic drugs on atherosclerosis by comparing carotid intima-media thickness (CIMT) as an indicator for cardiovascular diseases (CVD). This study included 44 female RA patients who met the 2010 ACR/EULAR criteria and age-matched 22 healthy females. CIMT was measured on both carotid arteries using a B-mode ultrasound scan. The mean value of both sides was taken as the CIMT of the subject. The CIMT was evaluated according to the use of drugs, disease activity and CVD risk factors in RA patients as a case-control study. Higher CIMT was observed in RA patients as compared with healthy subjects (0.705 ± 0.198 mm, 0.611 ± 0.093 mm, respectively, P < 0.05). With adjustment for the CVD risk factors, disease activity and the use of anti-rheumatic drugs, methotrexate (MTX) only showed a favorable effect on CIMT in RA. A significantly lower CIMT was observed in RA with MTX as compared with RA without MTX (0.644 ± 0.136 mm, 0.767 ± 0.233 mm, respectively, P < 0.05). The effects were correlated with MTX dosage (β = -0.029, P < 0.01). The use of MTX should be considered in high priority not only to control arthritis but also to reduce the RA-related CVD risk to mortality.

Prevention of stroke in rheumatoid arthritis

OPINION STATEMENT

Recognizing that systemic inflammation is a major contributor to the increased risk of cardiovascular disease (CVD), including stroke, in rheumatoid arthritis (RA) serves as the basis for prevention strategies for cerebrovascular disease in RA. In addition to traditional cardiovascular risk factors, recognize that RA may be an independent risk factor for cerebrovascular accident (CVA). The risk of CVD should be assessed in each patient with RA, utilizing modified risk score calculators. Careful monitoring and control of systemic inflammation should be undertaken in conjunction with assessing each patient's CVD risk, acknowledging the benefits and risks of specific RA-directed therapies. Emphasis should be given to early and aggressive control of inflammation in RA patients, particularly those with seropositivity, increased inflammatory markers, long disease duration (>10 years), and/or extra-articular manifestations. In RA patients requiring glucocorticoid therapy, attempts should be made to use or wean to the minimal effective dose (preferably less than 7.5 mg/day). It should be recognized that both disease-modifying antirheumatic drugs (DMARDs), particularly methotrexate, and tumor necrosis factor (TNF)-alpha inhibitors partially mitigate the risk of CVD. In patients with inadequate control of inflammation with DMARDs, consideration should be given to switch to anti-TNF agents earlier in the disease process. Modifiable risk factors should be addressed as per guidelines for the general population. Active RA may be considered as a risk equivalent to diabetes mellitus when applying these guidelines. With regard to lipid management and use of statin therapy, further studies are required given the apparent "lipid paradox" in RA. Use of aspirin for primary prevention in RA has not been well studied; however, when aspirin is used for secondary prevention, one should recognize that concomitant use of nonsteroidal anti-inflammatory drugs (NSAIDs) may decrease the antiplatelet effect. Given the cardiovascular risk associated with NSAIDs, the lowest possible dose for the shortest time should be used.

Potential mechanisms leading to the abnormal lipid profile in patients with rheumatoid arthritis versus healthy volunteers and reversal by tofacitinib

OBJECTIVE

Tofacitinib is an oral JAK inhibitor for the treatment of rheumatoid arthritis (RA). Systemic inflammation is proposed to play a fundamental role in the altered lipid metabolism associated with RA; however, the underlying mechanisms are unknown. We undertook this study to compare cholesterol and lipoprotein kinetics in patients with active RA with those in matched healthy volunteers.

METHODS

This was a phase I open-label mechanism-of-action study. Cholesterol and lipoprotein kinetics were assessed with (13) C-cholesterol and (13) C-leucine infusions. RA patients were reevaluated after receiving oral tofacitinib 10 mg twice daily for 6 weeks.

RESULTS

Levels of high-density lipoprotein (HDL) cholesterol, low-density lipoprotein (LDL) cholesterol, total cholesterol, and apolipoprotein A-I (Apo A-I) as well as HDL cholesterol particle number were lower in RA patients (n = 36) than in healthy volunteers (n = 33). In contrast, the cholesterol ester fractional catabolic rate was higher in RA patients, but no differences were observed in cholesterol ester transfer protein, cholesterol ester production rate, HDL-associated Apo A-I fractional catabolic rate, or LDL-associated Apo B fractional catabolic rate. Following tofacitinib treatment in RA patients, the cholesterol ester fractional catabolic rate decreased and cholesterol levels increased. The decrease in cholesterol ester fractional catabolic rate correlated significantly with the increase in HDL cholesterol. Additionally, HDL cholesterol particle number increased and markers of HDL cholesterol function improved.

CONCLUSION

This is the first study to assess cholesterol and lipoprotein kinetics in patients with active RA and matched healthy volunteers. The data suggest that low cholesterol levels in patients with active RA may be driven by increases in cholesterol ester catabolism. Tofacitinib treatment reduced cholesterol ester catabolism, thereby increasing cholesterol levels toward those in healthy volunteers, and markers of antiatherogenic HDL function improved.

Cardiovascular involvement in autoimmune diseases

Autoimmune diseases (AD) represent a broad spectrum of chronic conditions that may afflict specific target organs or multiple systems with a significant burden on quality of life. These conditions have common mechanisms including genetic and epigenetics factors, gender disparity, environmental triggers, pathophysiological abnormalities, and certain subphenotypes. Atherosclerosis (AT) was once considered to be a degenerative disease that was an inevitable consequence of aging. However, research in the last three decades has shown that AT is not degenerative or inevitable. It is an autoimmune-inflammatory disease associated with infectious and inflammatory factors characterized by lipoprotein metabolism alteration that leads to immune system activation with the consequent proliferation of smooth muscle cells, narrowing arteries, and atheroma formation. Both humoral and cellular immune mechanisms have been proposed to participate in the onset and progression of AT. Several risk factors, known as classic risk factors, have been described. Interestingly, the excessive cardiovascular events observed in patients with ADs are not fully explained by these factors. Several novel risk factors contribute to the development of premature vascular damage. In this review, we discuss our current understanding of how traditional and nontraditional risk factors contribute to pathogenesis of CVD in AD.

Anti-inflammatory therapies for cardiovascular disease

Atherothrombosis is no longer considered solely a disorder of lipoprotein accumulation in the arterial wall. Rather, the initiation and progression of atherosclerotic lesions is currently understood to have major inflammatory influences that encompass components of both the innate and acquired immune systems. Promising clinical data for 'upstream' biomarkers of inflammation such as interleukin-6 (IL-6) as well as 'downstream' biomarkers such as C-reactive protein, observations regarding cholesterol crystals as an activator of the IL-1β generating inflammasome, and recent Mendelian randomization data for the IL-6 receptor support the hypothesis that inflammatory mediators of atherosclerosis may converge on the central IL-1, tumour necrosis factor (TNF-α), IL-6 signalling pathway. On this basis, emerging anti-inflammatory approaches to vascular protection can be categorized into two broad groups, those that target the central IL-6 inflammatory signalling pathway and those that do not. Large-scale Phase III trials are now underway with agents that lead to marked reductions in IL-6 and C-reactive protein (such as canakinumab and methotrexate) as well as with agents that impact on diverse non-IL-6-dependent pathways (such as varespladib and darapladib). Both approaches have the potential to benefit patients and reduce vascular events. However, care should be taken when interpreting these trials as outcomes for agents that target IL-6 signalling are unlikely to be informative for therapies that target alternative pathways, and vice versa. As the inflammatory system is redundant, compensatory, and crucial for survival, evaluation of risks as well as benefits must drive the development of agents in this class.

Low levels of CD36 in peripheral blood monocytes in subclinical atherosclerosis in rheumatoid arthritis: a cross-sectional study in a Mexican population

Patients with rheumatoid arthritis (RA) have a higher risk for atherosclerosis. There is no clinical information about scavenger receptor CD36 and the development of subclinical atherosclerosis in patients with RA. The aim of this study was to evaluate the association between membrane expression of CD36 in peripheral blood mononuclear cells (PBMC) and carotid intima-media thickness (cIMT) in patients with RA.

METHODS

We included 67 patients with RA from the Rheumatology Department of Hospital Civil "Dr. Juan I. Menchaca," Guadalajara, Jalisco, Mexico. We evaluated the cIMT, considering subclinical atherosclerosis when >0.6 mm. Since our main objective was to associate the membrane expression of CD36 with subclinical atherosclerosis, other molecules related with cardiovascular risk such as ox-LDL, IL-6, and TNFα were tested.

RESULTS

We found low CD36 membrane expression in PBMC from RA patients with subclinical atherosclerosis (P < 0.001). CD36 mean fluorescence intensity had negative correlations with cIMT (r = -0.578, P < 0.001), ox-LDL (r = -0.427, P = 0.05), TNFα (r = -0.729, P < 0.001), and IL-6 (r = -0.822, P < 0.001).

CONCLUSION

RA patients with subclinical atherosclerosis showed low membrane expression of CD36 in PBMC and increased serum proinflammatory cytokines. Further studies are needed to clarify the regulation of CD36 in RA.

Targeting inflammation: impact on atherothrombosis

Atherothrombosis is a worldwide epidemic accounting for an unacceptable toll of deaths and disabilities. Its pathophysiology is complex and hardly referable to a specific mechanism; however, in the last 20 years, a growing amount of evidence has demonstrated that inflammatory processes play a major role from the very beginning to the ultimate complication of atherothrombosis. These evidences are addressing a growing interest toward anti-inflammatory agents as preventive or curative treatments of atherothrombosis. At present, accumulated data are not conclusive, but strong evidence exists in favor of an anti-inflammatory positive effect for several drugs as statins or renin-angiotensin inhibitors. More conclusive data are expected from ongoing trials directly exploring the role of specific cytokines antagonists.

Inflammation and atherosclerosis: disease modulating therapies

OPINION STATEMENT

Advances in the mechanistic understanding of atheroma initiation, repair, progression, and rupture have solidified the pivotal role played by the immune system in the pathophysiology of atherosclerotic vascular disease. These mechanistic findings have been extended into humans, with a strong evidence basis for the independent association between elevated blood markers of inflammation and future cardiovascular (CV) events. Investigations with statins as well as more conventional anti-inflammatory medications provide indirect evidence to support the concept that modifying immune responses can improve CV outcomes; however, robust evidence to support the use of anti-inflammatory treatment strategies to manage atherosclerotic vascular disease is still lacking. Such evidence may emerge from a new wave of clinical trials directly exploring the effects of targeted immune modulation on CV risk. These trials will provide key additional insights into atherosclerosis and will help determine the fate of immune modulation as a new treatment strategy in atherosclerotic vascular disease.

Rationale and design of the Cardiovascular Inflammation Reduction Trial: a test of the inflammatory hypothesis of atherothrombosis

BACKGROUND

Inflammation plays a fundamental role in atherothrombosis. Yet, whether direct inhibition of inflammation will reduce the occurrence of adverse cardiovascular outcomes is not known.

DESIGN

The Cardiovascular Inflammation Reduction Trial (CIRT) (ClinicalTrials.govNCT01594333) will randomly allocate 7,000 patients with prior myocardial infarction (MI) and either type 2 diabetes or the metabolic syndrome to low-dose methotrexate (target dose 15-20 mg/wk) or placebo over an average follow-up period of 3 to 5 years. Low-dose methotrexate is a commonly used anti-inflammatory regimen for the treatment of rheumatoid arthritis and lacks significant effects on lipid levels, blood pressure, or platelet function. Both observational and mechanistic studies suggest that low-dose methotrexate has clinically relevant antiatherothrombotic effects. The CIRT primary end point is a composite of nonfatal MI, nonfatal stroke, and cardiovascular death. Secondary end points are all-cause mortality, coronary revascularization plus the primary end point, hospitalization for congestive heart failure plus the primary end point, all-cause mortality plus coronary revascularization plus congestive heart failure plus the primary end point, incident type 2 diabetes, and net clinical benefit or harm. CIRT will use standardized central methodology designed to ensure consistent performance of all dose adjustments and safety interventions at each clinical site in a manner that protects the blinding to treatment but maintains safety for enrolled participants.

SUMMARY

CIRT aims to test the inflammatory hypothesis of atherothrombosis in patients with prior MI and either type 2 diabetes or metabolic syndrome, conditions associated with persistent inflammation. If low-dose methotrexate reduces cardiovascular events, CIRT would provide a novel therapeutic approach for the secondary prevention of heart attack, stroke, and cardiovascular death.

Changes in lipid levels with inflammation and therapy in RA: a maturing paradigm

Dyslipidaemia is commonly observed in patients with active rheumatoid arthritis (RA), with lower total cholesterol levels as well as lower levels of high-density lipoprotein cholesterol (HDL-C) and low-density lipoprotein cholesterol (LDL-C) reported in these patients than in individuals without RA. This pattern is mirrored in sepsis and other inflammatory states, suggesting systemic inflammation has the general effect of lowering circulating lipid levels. In line with such observations, suppressing inflammation with DMARDs, biologic therapies and small-molecule Janus kinase inhibitors seems to elevate levels of lipid fractions in RA, albeit in a variable manner dependent presumably upon the mechanism of action of the different agents. In addition, limited epidemiological data in patients with RA suggest increased cardiovascular disease (CVD) risk at relatively low cholesterol levels, a pattern contrasting with that observed in the population without RA. Our understanding of the potential mechanisms behind these inflammation-associated lipid changes remains suboptimal and requires further study. In clinical terms, however, use of the total cholesterol to HDL-C ratio as the lipid component of CVD risk scoring in patients with RA would seem appropriate given that these lipid parameters generally change in parallel with inflammation and suppression of inflammation. Whether alternative lipid or lipoprotein measures (or simple markers of inflammation) could improve stratification of CVD risk in RA beyond the established risk factors requires future investigation.

Moving beyond JUPITER: will inhibiting inflammation reduce vascular event rates?

The recent JUPITER trial demonstrated that potent statin therapy reduces by 50 % the risk of heart attack and stroke among men and women with low levels of low-density lipoprotein (LDL)-cholesterol who are at increased vascular risk due to elevated levels of C-reactive protein (CRP), a biomarker of low-grade systemic inflammation. In JUPITER, both absolute risk and the absolute risk reduction with statin therapy were related to the level of CRP, whereas no such relationship was observed for LDL-C. Further, on-treatment levels of CRP and LDL-C were independently associated with residual risk, and the genetic determinants of statin-induced CRP reduction differed from the genetic determinants of statin-induced LDL reduction. Despite these data, it is impossible in any statin trial to establish whether the clinical benefits of treatment are due to LDL-reduction alone, to inflammation inhibition, or to a combination of both processes. To address the hypothesis that lowering inflammation will lower vascular event rates, two large-scale placebo controlled trials using targeted anti-inflammatory agents for the secondary prevention of myocardial infarction have been initiated. The first trial, the Canakinumab Anti-Inflammatory Thrombosis Outcomes Study (CANTOS), is evaluating whether interleukin-1β (IL-1β) inhibition as compared to placebo can reduce rates of recurrent myocardial infarction, stroke, and cardiovascular death among stable coronary artery disease patients who remain at high vascular risk due to persistent elevations of hsCRP (≥ 2 mg/L), despite contemporary secondary prevention strategies. The second trial, the Cardiovascular Inflammation Reduction Trial (CIRT) has been funded by the National Heart, Lung, and Blood Institute (NHLBI) and will evaluate whether low dose methotrexate (target dose 20 mg/week) as compared to placebo will reduce major vascular events among a group of post-myocardial infarction patients with either diabetes or metabolic syndrome, groups known to have high risk on the basis of a persistent pro-inflammatory response. Together, CANTOS and CIRT represent a core test of the inflammation hypothesis of atherothrombosis and the exploration of a potential new phase for cardiovascular therapeutics.

Propensity-adjusted association of methotrexate with overall survival in rheumatoid arthritis

OBJECTIVE

While medications used to treat rheumatoid arthritis (RA) may affect survival in RA, few studies take into account the propensity for medication use, which may reflect selection bias in treatment allocation in survival models. We undertook this study to examine the relationship between methotrexate (MTX) use and mortality in RA, after controlling for individual propensity scores for MTX use.

METHODS

We studied 5,626 RA patients prospectively for 25 years to determine the risk of death associated with MTX use, modeled in time-varying Cox regression models. We used the random forest method to generate individual propensity scores for MTX use at study entry and during followup in a time-varying manner; these scores were included in the multivariate model. We also investigated whether selective discontinuation of MTX immediately prior to death altered the risk of mortality, and we examined the association of duration of MTX use with survival.

RESULTS

During followup, 666 patients (12%) died. MTX use was associated with reduced risk of death (adjusted hazard ratio 0.30 [95% confidence interval 0.09-1.03]). Selective MTX cessation immediately before death did not account for the protective association of MTX use with mortality. Only MTX use for >1 year was associated with lower risks of mortality, but associations were not stronger with longer durations of use.

CONCLUSION

MTX use was associated with a 70% reduction in mortality in RA.

Adenosine, adenosine receptors and their role in glucose homeostasis and lipid metabolism

Adenosine is an endogenous metabolite that is released from all tissues and cells including liver, pancreas, muscle and fat, particularly under stress, intense exercise, or during cell damage. The role of adenosine in glucose homeostasis has been attributed to its ability to regulate, through its membrane receptors, processes such as insulin secretion, glucose release and clearance, glycogenolysis, and glycogenesis. Additionally, adenosine and its multiple receptors have been connected to lipid metabolism by augmenting insulin-mediated inhibition of lipolysis, and the subsequent increase in free fatty acids and glycerol levels. Furthermore, adenosine was reported to control liver cholesterol synthesis, consequently affecting plasma levels of cholesterol and triglycerides, and the amount of fat tissue. Alterations in the balance of glucose and lipid homeostasis have implications in both cardiovascular disease and diabetes. The ability of different adenosine receptors to activate and inhibit the same signaling cascades has made it challenging to study the influence of adenosine, adenosine analogs and their receptors in health and disease. This review focuses on the role and significance of different adenosine receptors in mediating the effect of adenosine on glucose and lipid homeostasis. J. Cell. Physiol. © 2013 Wiley Periodicals, Inc.

Closing the loop on inflammation and atherothrombosis: why perform the CIRT and CANTOS trials?

Inflammation contributes to all phases of the atherothrombotic process, patients with elevated inflammatory biomarkers such as high-sensitivity C-reactive protein (hsCRP) have increased cardiovascular risk, and recent work directly implicates the interleukin-1 (IL-1) and interleukin-6 (IL-6) pathways in atherogenesis. Yet, it remains unknown whether targeted inhibition of inflammation will reduce cardiovascular event rates. To address directly this fundamental hypothesis, our research group has initiated two large-scale, randomized, placebo-controlled trials using targeted anti-inflammatory agents for the secondary prevention of myocardial infarction. The first trial, the Cardiovascular Inflammation Reduction Trial (CIRT), has been funded by the NHLBI and will evaluate whether low-dose methotrexate (target dose, 20 mg/wk) as compared to placebo will reduce major vascular events among a group of post-myocardial infarction patients with either diabetes or metabolic syndrome, groups known to have high risk on the basis of a persistent pro-inflammatory response. CIRT is based, in part, on observational evidence of reduced vascular event rates among those treated with methotrexate in the setting of rheumatoid arthritis or psoriatic arthritis and on the ability of methotrexate to reduce TNF, IL-6, and CRP levels. The second trial, the Canakinumab Anti-Inflammatory Thrombosis Outcomes Study (CANTOS), will evaluate whether interleukin-1β (IL-1β) inhibition as compared to placebo can reduce rates of recurrent myocardial infarction, stroke, and cardiovascular death among stable coronary artery disease patients who remain at high vascular risk due to persistent elevations of hsCRP (_2 mg/L) despite contemporary secondary prevention strategies. Canakinumab is a human monoclonal antibody that selectively neutralizes IL-1β, a pro-inflammatory cytokine that plays multiple roles in the atherothrombotic process and that undergoes activation by the NLRP3 inflammasome, a process promoted by cholesterol crystals that in turn leads directly to increased production of IL-1 and IL-6. Together, CIRT and CANTOS will enroll more than 25,000 patients worldwide and provide a fundamental test of the inflammatory hypothesis of atherothrombosis.

Adenosine A(2A) receptor activation supports an atheroprotective cholesterol balance in human macrophages and endothelial cells

The adenosine A(2A) receptor (A(2A)R) plays an important role in the regulation of inflammatory and immune responses. Our previous work has demonstrated that A(2A)R agonists exhibit atheroprotective effects by increasing expression of reverse cholesterol transport proteins in cultured human macrophages. This study explores the impact of pharmacologic activation/inhibition and gene silencing of A(2A)R on cholesterol homeostasis in both THP-1 human monocytes/macrophages and primary human aortic endothelial cells (HAEC). THP-1 human monocytes/macrophages and HAEC exposed to the A(2A)R-specific agonist ATL313 exhibited upregulation of proteins responsible for cholesterol efflux: the ABCA1 and G1 transporters. Further, activation of A(2A)R led to upregulation of the cholesterol metabolizing enzyme P450 27-hydroxylase, accompanied by intracellular changes in level of oxysterols. We demonstrate that anti-atherogenic properties of A(2A)R activation are not limited to the regulation of lipid efflux in vasculature, but include protection from lipid overload in macrophages, particularly via suppression of the CD36 scavenger receptor. The reduced lipid accumulation manifests directly as a diminution in foam cell transformation. In THP-1 macrophages, either A(2A)R pharmacological blockade or gene silencing promote lipid accumulation and enhance foam cell transformation. Our pre-clinical data provides evidence suggesting that A(2A)R stimulation by ATL313 has the potential to be a viable therapeutic strategy for cardiovascular disease prevention, particularly in patients with elevated risk due to immune/inflammatory disorders.

Dyslipidemia and changes in lipid profiles associated with rheumatoid arthritis and initiation of anti-tumor necrosis factor therapy

OBJECTIVE

To investigate the frequency of lipid testing in clinical practice and to explore the relationship between rheumatoid arthritis (RA), dyslipidemia, and other cardiovascular (CV) risk factors with RA treatment.

METHODS

Patients in this retrospective database study were ages ≥18 years and had ≥2 physician diagnoses for RA or osteoarthritis (OA; comparator group) between March 2004 and March 2008. Outcomes of interest included the percentage of RA and OA patients receiving lipid tests, lipid profiles (total cholesterol, low-density lipoprotein [LDL] cholesterol, and high-density lipoprotein [HDL] cholesterol) of RA versus OA patients, and lipid profiles of RA patients before and after initiation with a tumor necrosis factor (TNF) inhibitor. We used multivariable regression to control potential confounders between the cohorts.

RESULTS

Over a median ≥2-year followup, fewer RA patients than OA patients had ≥1 lipid test (62.0% [95% confidence interval (95% CI) 61.5-62.5] versus 69.8% [95% CI 69.5-70.1]). Mean total cholesterol and LDL cholesterol were each 4 mg/dl lower in the RA cohort (P < 0.0001); HDL cholesterol was similar between the cohorts. Across the RA cohort, 25.2% of patients had suboptimal LDL cholesterol levels (≥130 mg/dl). Among RA patients not receiving lipid-lowering therapy who initiated TNF inhibitor therapy (n = 96), mean total cholesterol and LDL cholesterol increased by 5.4 and 4.0 mg/dl, respectively.

CONCLUSION

Patients with RA were less likely to be tested for hyperlipidemia and had more favorable lipid profiles than patients with OA. TNF inhibitor therapy modestly increased all lipid parameters. Additional studies are needed to determine the effect of traditional CV risk factors and inflammation and the impact of biologic agents on CV outcomes in RA patients.

Resveratrol mediates anti-atherogenic effects on cholesterol flux in human macrophages and endothelium via PPARγ and adenosine

Resveratrol is a bioactive molecule used in dietary supplements and herbal medicines and consumed worldwide. Known cardioprotective and anti-inflammatory properties of resveratrol have spurred investigation of the mechanisms involved. The present study explored potential atheroprotective actions of resveratrol on cholesterol metabolism in cells of the arterial wall, including human macrophages and arterial endothelium. Using QRT-PCR and Western blotting techniques, we measured expression of the proteins involved in reverse cholesterol transport (ABCA1, ABCG1 and SR-B1) and the scavenger receptors responsible for uptake of modified cholesterol (CD36, SR-A1 and LOX-1). We analyzed the effect of resveratrol on apoA-1-and HDL-mediated cholesterol efflux in human THP-1 macrophages. The effect of resveratrol on oxLDL internalization and foam cell formation were evaluated using confocal and light microscopy. Our data indicate that resveratrol regulates expression of major proteins involved in cholesterol transport, promotes apoA-1 and HDL-mediated efflux, downregulates oxLDL uptake and diminishes foam cell formation. Mechanistically, resveratrol effects were dependent upon PPAR-γ and adenosine 2A receptor pathways. For the first time we demonstrate that resveratrol regulates expression of the cholesterol metabolizing enzyme cytochrome P450 27-hydroxylase, providing efficient cholesterol elimination via formation of oxysterols. This study establishes that resveratrol attenuates lipid accumulation in cultured human macrophages via effects on cholesterol transport. Further in vivo studies are needed to determine whether resveratrol may be an additional resource available to reduce lipid deposition and atherosclerosis in humans.

Semiquantified noncalcified coronary plaque in systemic lupus erythematosus

OBJECTIVE

A major cause of morbidity and mortality in systemic lupus erythematosus (SLE) is accelerated coronary atherosclerosis. New technology (computed tomographic angiography) can measure noncalcified coronary plaque (NCP), which is more prone to rupture. We report on a study of semiquantified NCP in SLE.

METHODS

Patients with SLE (n = 147) with no history of cardiovascular disease underwent 64-slice coronary multidetector computed tomography (MDCT). The MDCT scans were evaluated quantitatively by a radiologist, using dedicated software.

RESULTS

The group of 147 patients with SLE was 86% female, 70% white, 29% African American, and 3% other ethnicity. The mean age was 51 years. In our univariate analysis, the major traditional cardiovascular risk factors associated with noncalcified plaque were age (p = 0.007), obesity (p = 0.03; measured as body mass index), homocysteine (p = 0.05), and hypertension (p = 0.04). Anticardiolipin (p = 0.026; but not lupus anticoagulant) and anti-dsDNA (p = 0.03) were associated with higher noncalcified plaque. Prednisone and hydroxychloroquine therapy had no effect, but methotrexate (MTX) use was associated with higher noncalcified plaque (p = 0.0001). In the best multivariate model, age, current MTX use, and history of anti-dsDNA remained significant.

CONCLUSION

Our results suggest that serologic SLE (anti-dsDNA) and traditional cardiovascular risk factors contribute to semiquantified noncalcified plaque in SLE. The association with MTX is not understood, but should be replicated in larger studies and in multiple centers.

Mechanisms of premature atherosclerosis in rheumatoid arthritis and lupus

Rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE), the two most common systemic autoimmune disorders, have both unique and overlapping manifestations. One feature they share is a significantly enhanced risk of atherosclerotic cardiovascular (CV) disease that significantly contributes to morbidity and mortality. The primary mechanisms that drive CV damage in these diseases remain to be fully characterized, but recent discoveries indicate that distinct inflammatory pathways and immune dysregulation characteristic of RA and SLE likely play prominent roles. This review focuses on analyzing the major mechanisms and pathways potentially implicated in the acceleration of atherothrombosis and CV risk in SLE and RA, as well as in the identification of putative preventive strategies that may mitigate vascular complications in systemic autoimmunity.

The effect of A(2A) adenosine receptor activation on C-C chemokine receptor 7 expression in human THP1 macrophages during inflammation

C-C chemokine receptor 7 (CCR7) and its chemoattractant agonist CCL21 promote cell migration and expression of pro-inflammatory proteins in an atherogenic environment. Since A(2A) adenosine receptor activation reduces migration and inflammatory effects, we examined its effect on CCR7 expression and migration. CCR7 protein expression decreased by about a third in macrophages treated with A(2A) receptor agonist CGS 21680 (p = 0.028, n = 7) and was reversed with antagonist, although mRNA levels increased twofold (p = 0.001, n = 3). Furthermore, macrophages treated with CGS 21680 showed a significant decrease in migration (p = 0.0311, n = 7). These results suggest that A(2A) adenosine receptor activation not only modulates CCR7 expression in both normal and inflammatory environments but also regulates macrophage migration to CCR7-specific chemoattractants.

Protective effect of methotrexate in patients with rheumatoid arthritis and cardiovascular comorbidity

Rheumatoid arthritis (RA) is associated with an increased risk of premature mortality, predominantly due to increased cardiovascular disease (CVD). Systemic inflammation has been established as one of the primary drivers of accelerated atherosclerosis in RA, though other traditional and disease-specific risk factors also contribute. There is evidence that methotrexate, considered a mainstay of therapy for RA, can ameliorate some of this excess CVD risk, an effect that has not been seen consistently with other disease-modifying antirheumatic drugs. The cardioprotective action of methotrexate may occur through reducing systemic inflammation and by directly affecting some of the cellular mechanisms that lead to atherosclerosis. On the basis of this evidence, there are ongoing trials of low-dose methotrexate in patients from the general population with CVD but who do not have RA. Methotrexate reduces the overall CVD burden in patients with RA. With earlier treatment of RA and earlier use of methotrexate it is possible that we may have the capability to radically change patients' long-term CVD risk.

Cholesterol 27-hydroxylase but not apolipoprotein apoE contributes to A2A adenosine receptor stimulated reverse cholesterol transport

Movement of free cholesterol between the cellular compartment and acceptor is governed by cholesterol gradients that are determined by several enzymes and reverse cholesterol transport proteins. We have previously demonstrated that adenosine A(2A) receptors inhibit foam cell formation and stimulate production of cholesterol 27-hydroxylase (CYP27A1), an enzyme involved in the conversion of cholesterol to oxysterols. We therefore asked whether the effect of adenosine A(2A) receptors on foam cell formation in vitro is mediated by CYP27A1 or apoE, a carrier for cholesterol in the serum. We found that specific lentiviral siRNA infection markedly reduced apoE or 27-hydroxylase mRNA in THP-1 cells. Despite diminished apoE expression (p < 0.0002, interferon-gamma (IFNγ) CGS vs. IFNγ alone, n=4), CGS-21680, an adenosine A(2A) receptor agonist, inhibits foam cell formation. In contrast, CGS-21680 had no effect on reducing foam cell formation in CYP27A1 KD cells (4 ± 2%; p<0.5113, inhibition vs. IFNγ alone, n=4). Previously, we reported the A(2A) agonist CGS-21680 increases apoAI-mediated cholesterol efflux nearly twofold in wild-type macrophages. Adenosine receptor activation had no effect on cholesterol efflux in CYP27A1 KD cells but reduced efflux in apoE KD cells. These results demonstrate that adenosine A(2A) receptor occupancy diminishes foam cell formation by increasing expression and function of CYP27A1.

The time course of gastric methotrexate intolerance in patients with rheumatoid arthritis and psoriatic arthritis

OBJECTIVES

This study aimed to evaluate the incidence and the time course of methotrexate (MTX)-associated gastric intolerance in patients with rheumatoid arthritis and psoriatic arthritis.

METHODS

Four hundred twenty subjects undergoing MTX treatment for rheumatoid arthritis (n = 346) and psoriatic arthritis (n = 74) were retrospectively assessed. The incidence and time course of gastric MTX intolerance resulting in treatment discontinuation were investigated. In addition, the relations between gastric intolerance and patient characteristics, including gender, age, diagnosis, and rheumatoid factor (RF) positivity, were examined.

RESULTS

Overall, oral MTX discontinuation rate due to gastric intolerance was 28.6 %. The time to discontinuation for oral MTX was 8.1 ± 11.5 months on average, with more than half of the discontinuations occurring within the first three months of treatment. Discontinuation was not associated with gender, age, diagnosis, or RF positivity. More than half of the patients that switched to a parenteral treatment regimen (52.6 %, 20/38) could tolerate the agent.

CONCLUSIONS

Gastric MTX intolerance usually develops within the first year of treatment and presents a major obstacle to long-term treatment retention in patients with rheumatologic disease. However, parenteral MTX appears to be a good alternative for patients intolerant of oral MTX.

Methotrexate Increases Skeletal Muscle GLUT4 Expression and Improves Metabolic Control in Experimental Diabetes

Long-term administration of 5-aminoimidazole-4-carboxamide ribonucleoside (AICAR) mimics the effects of endurance exercise by activating AMP kinase and by increasing skeletal muscle expression of GLUT4 glucose transporter. AICAR is an intermediate in the purine de novo synthesis, and its tissue concentrations can be increased, in vivo, by low doses of methotrexate (MTX) through the inhibition of the enzyme AICAR transformylase. We report here the first evidence that, in experimental type 2 diabetes, chronic treatment with low doses of MTX increases skeletal muscle GLUT4 expression and improves metabolic control. MTX (0.5 mg/kg body weight) or vehicle was administered intraperitoneally, once a week for 4 weeks, to genetically diabetic female C57BL/KsJ-m(+)/(+)Lept(db) mice (db(+)/db(+)) and their normoglycemic littermates (db(+)/(+)m). In the db(+)/db(+) mice, MTX treatment was associated with a ∼2-fold increase in skeletal muscle GLUT4 protein concentration and a >4-fold increase in GLUT4 mRNA expression (P < 0.01, all), as compared to vehicle-treated mice; no significant differences were noted in controls. MTX treatment was also associated with a significant reduction of glucose and insulin serum concentrations in diabetic mice (P < 0.001), and glucose levels only (P < 0.05) in controls. These data indicate a different route to increase skeletal muscle GLUT4 expression, through the potential inhibition of the enzyme AICAR transformylase.

Adenosine receptor expression in rheumatoid synovium: a basis for methotrexate action

INTRODUCTION

Methotrexate (MTX) exerts at least part of its anti-inflammatory effects through adenosine receptors (ADOR). The aims of this study were to determine the expression of all four adenosine receptor genes (ADORA1, ADORA2A, ADORA2B, ADORA3 and ADORA3variant) in rheumatoid synovial tissue and any influence of MTX exposure on this expression. Furthermore, we investigated whether polymorphisms within ADORA3 were associated with response and/or adverse effects associated with MTX.

METHODS

Adenosine receptor gene expression was undertaken using PCR in 20 rheumatoid arthritis (RA) synovial samples. A separate cohort of 225 RA patients receiving MTX was genotyped for SNPs in the ADORA3 receptor gene. Double immunofluorescence was used to identify cells expressing ADOR protein.

RESULTS

All ADOR genes were expressed in all synovial samples. ADORA3 and A3variant were the dominant subtypes expressed irrespective of MTX therapy. Expression of ADORA2A and ADORA2B was increased in patients receiving MTX compared to those not receiving MTX. There was no association between the ADORA3 rs1544224 SNP and high and low disease activity or MTX-associated adverse effects. ADORA2B protein expression was most obvious in vascular endothelial cells whereas ADORA3 protein was more abundant and expressed by synovial fibroblasts.

CONCLUSIONS

We have shown that adenosine receptors are expressed in RA synovium. There is differential expression of receptors such that ADORA3 is expressed at significantly higher levels. This evidence demonstrates the potential for MTX to exert its anti-inflammatory effects at the primary site of pathology within the joints of patients with RA.