Mycophenolate Mofetil and Atherosclerosis: Results of Animal and Human Studies

Crosstalk between Inflammation and Atherosclerosis in Rheumatoid Arthritis and Systemic Lupus Erythematosus: Is There a Common Basis?

Cardiovascular disease is the leading cause of morbidity and mortality in patients with rheumatoid arthritis and systemic lupus erythematosus. Traditional cardiovascular risk factors, although present in lupus and rheumatoid arthritis, do not explain such a high burden of early cardiovascular disease in the context of these systemic connective tissue diseases. Over the past few years, our understanding of the pathophysiology of atherosclerosis has changed from it being a lipid-centric to an inflammation-centric process. In this review, we examine the pathogenesis of atherosclerosis in systemic lupus erythematosus and rheumatoid arthritis, the two most common systemic connective tissue diseases, and consider them as emblematic models of the effect of chronic inflammation on the human body. We explore the roles of the inflammasome, cells of the innate and acquired immune system, neutrophils, macrophages, lymphocytes, chemokines and soluble pro-inflammatory cytokines in rheumatoid arthritis and systemic lupus erythematosus, and the roles of certain autoantigens and autoantibodies, such as oxidized low-density lipoprotein and beta2-glycoprotein, which may play a pathogenetic role in atherosclerosis progression.

Comparative risks of cardiovascular disease events among SLE patients receiving immunosuppressive medications

OBJECTIVES

SLE patients have elevated cardiovascular disease (CVD) risk, but it is unclear whether this risk is affected by choice of immunosuppressive drug. We compared CVD risks among SLE patients starting MMF, CYC or AZA.

METHODS

Using Medicaid Analytic eXtract (2000-2012), adult SLE patients starting MMF, CYC or AZA were identified and propensity scores (PS) were estimated for receipt of MMF vs CYC and MMF vs AZA. We examined rates of first CVD event (primary outcome), all-cause mortality, and a composite of first CVD event and all-cause mortality (secondary outcomes). After 1:1 PS-matching, Fine-Gray regression models estimated subdistribution hazard ratios (HRs.d.) for risk of CVD events. Cox regression models estimated HRs for all-cause mortality. The primary analysis was as-treated; 6- and 12-month intention-to-treat (ITT) analyses were secondary.

RESULTS

We studied 680 PS-matched pairs of patients with SLE initiating MMF vs CYC and 1871 pairs initiating MMF vs AZA. Risk of first CVD event was non-significantly reduced for MMF vs CYC [HRs.d 0.72 (95% CI: 0.37, 1.39)] and for MMF vs AZA [HRs.d 0.88 (95% CI: 0.59, 1.32)] groups. In the 12-month ITT, first CVD event risk was lower among MMF than AZA new users [HRs.d 0.68 (95% CI: 0.47, 0.98)].

CONCLUSION

In this head-to-head PS-matched analysis, CVD event risks among SLE patients starting MMF vs CYC or AZA were not statistically reduced except in one 12-month ITT analysis of MMF vs AZA, suggesting longer-term use may convey benefit. Further studies of potential cardioprotective benefit of MMF are necessary.

Pathogenesis and treatment of atherosclerosis in lupus

The prevalence of atherosclerosis (ATH) is higher in patients with systemic lupus erythematosus (SLE) and occurs at an earlier age. The lupus-related factors that account for this increased risk are likely numerous and related to the factors described in this article. Identifying of at-risk subjects and increasing the understanding of pathogenesis of ATH in SLE is critical for improving the quality of care and improving mortality in this vulnerable population.

Mycophenolic acid attenuates the tumour necrosis factor-α-mediated proinflammatory response in endothelial cells by blocking the MAPK/NF-κB and ROS pathways

BACKGROUND

Mycophenolate mofetil (MMF) has beneficial effects in cardiac transplant patients beyond the suppression of tissue rejection. Moreover, mycophenolic acid (MPA), its active metabolite, has been associated with positive effects on atherosclerosis in animal models. The attachment of leukocytes to the vascular endothelium and the subsequent migration of these cells into the vessel wall are early events in inflammation and atherosclerosis. The aim of this study was to investigate the effects of MPA on tumour necrosis-α (TNF-α)-induced, endothelial cell proinflammatory responses and the underlying mechanisms.

METHODS AND RESULTS

Human aortic endothelial cells (HAECs) were treated with different concentrations (primarily 50 μM) of MPA before treatment with TNF-α. The surface protein and mRNA expressions of intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) were determined by flow cytometry and real-time RT-PCR, respectively. Adhesion of leukocytes to TNF-α-treated HAECs was evaluated by an adhesion assay. Activation of mitogen-activated protein kinase (MAPK) and nuclear factor-κB (NF-κB) was evaluated by measuring the levels of their phosphorylation using flow cytometry. NF-κB p65 translocation was detected by Western blotting. The production of reactive oxygen species (ROS) was determined by reduction in fluorescent 2',7'-dichlorofluorescein diacetate (H2 DCFH-DA). MPA significantly inhibits TNF-α-induced ICAM-1, VCAM-1 surface protein and mRNA expression as well as adhesion of mononuclear leukocytes to HAEC. ICAM-1 and VCAM-1 expressions were also reduced by antioxidants such as pyrrolidine dithiocarbamate, diphenylene iodonium and apocynin. MPA inhibited TNF-α-stimulated ROS generation similarly to apocynin. TNF-α increased ICAM-1 and VCAM-1 expression via c-Jun NH2 -terminal kinase (JNK), extracellular signal-regulated kinase (ERK1/2) and p38 MAPK. MPA and apocynin inhibited TNF-α-induced phosphorylation of all three MAP kinases. Furthermore, TNF-α-induced NF-κB activation was attenuated by SP600125 (JNK inhibitor), PD98059 (ERK1/2 inhibitor, SB203580 (p38 MAPK inhibitor) and MPA. MPA also inhibited TNF-α-induced nuclear translocation of NF-κB p65.

CONCLUSION

These results suggest that, in addition to the prevention of rejection, MPA may be a promising approach for the treatment of inflammatory vascular disease.

Acute effects of fructose consumption on uric acid and plasma lipids in patients with impaired renal function

OBJECTIVE

Metabolic disturbances are common in patients with renal function impairment and are related to high rates of cardiovascular incidents and mortality. Kidney transplantation leads to improved survival but may lead to additional metabolic alterations caused by immunosuppressive drugs and improved nutrition.

MATERIALS AND METHODS

The short-term effect of oral fructose load on serum uric acid (UA), plasma lipids, and blood pressure (BP) was studied in 85 patients with chronic kidney disease (CKD) and impairment of renal function (glomerular filtration rate 50-65 ml/min per 1.73 m(2)), comprising 55 renal transplant recipients (RTR) treated with standard triple immunosuppressive therapy including a calcineurin inhibitor (CNI) cyclosporine A (CsA) or tacrolimus (Tac) and 30 non-transplanted patients with CKD. Both non-transplanted CKD patients and RTR had stable renal function and a comparable degree of kidney dysfunction. All subjects received orally 70 g of fructose dissolved in 200 ml of water. Serum UA, lipids, and blood pressure were measured at baseline and 60, 120, 180, and 240 minutes after fructose administration.

RESULTS

There was a significant increase of serum UA concentration (p<0.001) in both CKD patients and RTR--CsA- or Tac-treated patients comparable in the latter. Total cholesterol (TC), LDL, and HDL cholesterol significantly decreased and serum triglycerides (TG) markedly increased in RTR, whereas in CKD patients all serum lipid fractions increased. Blood pressure was unaffected by fructose intake.

CONCLUSION

Both non-transplanted and transplanted patients with mild renal function impairment show similar acute purine metabolic disturbances following oral administration of fructose but in the latter dietary fructose may induce a smaller hyperlipidemic response.

Atherosclerosis in systemic lupus erythematosus

Accelerated atherosclerosis and its long-term sequelae are a major cause of late mortality among patients with systemic lupus erythematosus (SLE). Traditional Framingham risk factors such as hypertension, hypercholesterolemia, diabetes, and smoking do not account in entirety for this risk. SLE specific factors like disease activity and duration, use of corticosteroids, presence of antiphospholipid antibodies, and others are important risk factors. SLE is considered a coronary heart disease; equivalent and aggressive management of all traditional risk factors is recommended. Despite their role in primary and secondary prevention in the general population, statins seem to have no effect on cardiovascular outcomes in adult or pediatric SLE populations. The use of hydroxychloroquine has a cardioprotective effect, and mycophenolate mofetil may reduce cardiovascular events based on basic science data and data from the transplant population. The role of vitamin D supplementation and treatment of hyperhomocysteinemia remain controversial, but due to the safety of therapy and the potential benefit, they remain as optional therapies.

The effect of mycophenolate mofetil on disease development in the gld.apoE (-/-) mouse model of accelerated atherosclerosis and systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a systemic autoimmune disease that is characterized by autoantibody production and inflammatory disease involving multiple organs. Premature atherosclerosis is a common complication of SLE and results in substantial morbidity and mortality from cardiovascular disease (CVD). The reasons for the premature atherosclerosis in SLE are incompletely understood, although chronic inflammation is thought to play an important role. There is currently no known preventative treatment of premature atherosclerosis in SLE. Mycophenolate mofetil (MMF) is an immunosuppressive agent that is commonly used for treatment of patients with SLE. In order to study the impact of this drug on murine lupus disease including premature atherosclerosis development, we treated gld.apoE^−/− mice, a model of SLE and accelerated atherosclerosis, with MMF. We maintained seven-week old gld.apoE^−/− mice on a high cholesterol Western diet with or without MMF. After 12 weeks on diet, mice receiving MMF showed decreased atherosclerotic lesion area compared to the control group. MMF treatment also improved the lupus phenotype, indicated by a significant decrease circulating autoantibody levels and ameliorating lupus nephritis associated with this model. This data suggests that the effects of MMF on the immune system may not only be beneficial for lupus, but also for inflammation driving lupus-associated atherosclerosis.

In vitro and in vivo characterization of AS2643361, a novel and highly potent inosine 5'-monophosphate dehydrogenase inhibitor

Inosine 5'-monophosphate (IMP) dehydrogenase is a critical target in solid organ transplantation. To this end, the development of mycophenolate mofetil (MMF) represents a major advance in transplant medicine. Here, we investigated the in vitro and in vivo pharmacological effects of a novel IMP dehydrogenase inhibitor, AS2643361, in several immunological and non-immunological models. The in vitro inhibitory activity of AS2643361 on immune cell and endothelial cell proliferation and on antibody production from lipopolysaccharide-stimulated B cells, was significantly more potent than that of mycophenolic acid, the active form of MMF, despite the similar potency of these compounds on IMP dehydrogenase. In a rat heterotopic cardiac transplant model, monotherapy using orally administered AS2643361 at 10 or 20mg/kg/day prolonged the median graft survival time from 6 to 16 and 19days, respectively. In dinitrophenol-lipopolysaccharide stimulated rats, oral administration of AS2643361 at 2.5, 5 or 10mg/kg/day resulted in suppression of antibody production. In vivo antibody production against alloantigen was also suppressed by AS2643361 treatment at 5 or 10mg/kg/day. Furthermore, treatment with AS2543361 effectively inhibited balloon injury induced-intimal thickening, which is a major cause of late allograft loss. Overall, the in vivo activity of AS2643361 was over two-fold more potent than that of MMF. In addition, gastrointestinal toxicity, considered a dose-limiting factor for MMF, was reduced with AS2643361 treatment. These results suggest AS2643361 has higher potency and less toxicity than MMF, making it a potential candidate for treatment of acute and chronic rejection in transplant medicine.

Mycophenolate mofetil but not atorvastatin attenuates atherosclerosis in lupus-prone LDLr(-/-) mice

RATIONALE

Recent clinical and preclinical studies have demonstrated that systemic lupus erythematosus (SLE) is associated with an increased risk for cardiovascular disease (CVD). However, unlike in the general population, little is known regarding the efficacy of atheroprotective interventions in patients with SLE. The current study aims to determine the benefit of lymphocyte inhibition on reducing the atherosclerotic burden in SLE-susceptible LDLr-deficient mice.

METHODS

Female LDLr(-/-) mice were lethally irradiated and reconstituted with bone marrow from C57Bl/6 mice (LDLr.B6) or the SLE-susceptible B6.Sle1.2.3 mice (LDLr.Sle). At 16 weeks post transplant, mice were treated with atorvastatin (10 mg/kg), mycophenolate mofetil (MMF; 40 mg/kg), or both (MMF-A) for 8 weeks, after which the extent of atherosclerosis and the presence of SLE were assessed.

RESULTS

Following 8 weeks of treatment, we observed that atorvastatin-mediated reduction in cholesterol levels attenuated atherogenesis in LDLr.B6 mice but failed to significantly reduce atherosclerotic lesion size in LDLr.Sle mice, in spite of a significant reduction in serum cholesterol levels. Treatment with MMF and MMF-A attenuated atherogenesis in LDLr.B6 and LDLr.Sle mice. In addition, MMF-containing regimens inhibited recruitment of CD4+ T cells to atherosclerotic lesions in LDLr.Sle mice. In these mice, MMF also reduced the proportion of activated splenic T cells, as well as interleukin 10 secretion by T cells. With regard to lupus activity, MMF had no overt effect on anti-double-stranded DNA (dsDNA) antibody titres or kidney function and pathology.

CONCLUSIONS

The current study demonstrates that reduction of cholesterol levels alone is not atheroprotective in lupus-mediated atherogenesis. This is the first study to demonstrate that MMF reduces the atherosclerotic burden in a model of lupus-accelerated atherosclerosis. Our results suggest that MMF treatment may prove beneficial in preventing CVD in patients with SLE.

Mycophenolate mofetil decreases atherosclerotic lesion size by depression of aortic T-lymphocyte and interleukin-17-mediated macrophage accumulation

OBJECTIVES

This study tested whether immunosuppression with mycophenolate mofetil (MMF) inhibits atherosclerosis development in apolipoprotein-E-deficient (Apoe(-/-)) mice and investigated the mechanism.

BACKGROUND

Chronic vascular inflammation involving both innate and adaptive immunity is central in the development of atherosclerosis, but immunosuppressive treatment is not uniformly beneficial. The immunosuppressive MMF targets lymphocyte proliferation by inhibiting inosine-monophosphate dehydrogenase.

METHODS

Young and aged Apoe(-/-) mice were treated with 30 mg/kg daily MMF during 12 and 3 weeks of a high-fat diet, respectively. Aortic lesion size and composition was investigated by histology and flow cytometry; soluble inflammatory mediators were investigated by enzyme-linked immunosorbent assay.

RESULTS

Macroscopic and histologic aortic atherosclerotic lesions were significantly decreased in both MMF-treated groups. While systemic immunoglobulin G directed against low-density lipoproteins was not significantly altered, the T-cell cytokine interleukin (IL)-17 was significantly reduced in plasma of MMF-treated mice and supernatants from their aortas after T-cell stimulation. The MMF treatment decreased aortic αβ T-cell receptor(+) lymphocyte proliferation and cell numbers. Also, aortic contents of CD11b(+)CD11c(+) cells and their proliferation were reduced in MMF-treated Apoe(-/-) mice. The IL-17 supplementation restored the number of proliferating aortic CD11b(+)CD11c(+) cells in MMF-treated mice. The IL-17 receptor A was highly expressed on circulating monocytes that are macrophage progenitors. Genetic deletion of IL-17 receptor A or IL-17A reduced inflammatory peritoneal CD11b(+)CD11c(+) macrophage accumulation.

CONCLUSIONS

The lymphocyte-directed immunosuppressant MMF that curbs IL-17 production was a successful antiatherosclerotic treatment. Our data delineate a role for IL-17 in CD11b(+)CD11c(+) cell accumulation.

The interplay of inflammation and cardiovascular disease in systemic lupus erythematosus

Patients with systemic lupus erythematosus have up to a 50-fold increased risk of developing atherosclerotic cardiovascular disease. Recent advances in the etiology of vascular damage in this disease stress the interplay of lupus-specific inflammatory factors with traditional cardiac risk factors, leading to increased endothelial damage. This review analyzes the putative role that immune dysregulation and lupus-specific factors may play in the pathogenesis of premature vascular damage in this disease. The potential role of various cytokines, in particular type I interferons, in the development of accelerated atherosclerosis is examined. Potential therapeutic targets are discussed.

Management of cardiovascular complications in systemic lupus erythematosus

Cardiovascular disease (CVD) is a major cause of morbidity and mortality in patients with systemic lupus erythematosus (SLE). Patients with SLE have an excess risk compared with the general population; this is particularly pronounced in younger women with SLE who have an excess risk of over 50-fold compared with population controls. There is a higher prevalence of subclinical atherosclerosis in patients with SLE compared with controls, as demonstrated by a variety of imaging modalities discussed in this review. The causality of the excess risk of CVD and subclinical atherosclerosis is multifactorial in patients with SLE. While traditional risk factors play a role, after controlling for the traditional Framingham risk factors, the excess risk is still 7.5-fold greater than the general population. This review will also cover novel cardiovascular risk factors and some SLE-specific variables that contribute to CVD risk. This review discusses the risk factor modification and the evidence available for treatment of these risk factors in SLE. There have not yet been any published randomized, controlled trials in patients with SLE with respect to CVD risk factor modifications. Thus, the treatment and management recommendations are based largely on published guidelines for other populations at high risk for CVD.

Mycophenolic acid attenuates tumor necrosis factor-alpha-induced endothelin-1 production in human aortic endothelial cells

AIMS

Atherosclerotic cardiovascular disease is the major cause of morbidity and mortality in solid organ transplant recipients. Endothelin-1 (ET-1) is implicated in the pathogenesis of atherosclerosis and is one of the potential therapeutic targets. This study was conducted to evaluate the effect of mycophenolic acid (MPA), an immunosuppressant for the transplant recipients, on tumor necrosis factor-alpha (TNF-alpha)-induced ET-1 production in aortic endothelial cells.

METHODS AND RESULTS

In cultured human aortic endothelial cells, TNF-alpha increased ET-1 through AP-1 and NF-kappaB, whereas MPA attenuated it by reducing both AP-1 and NF-kappaB DNA-binding activities. TNF-alpha increased ET-1 via c-Jun NH2-terminal kinase (JNK) and p38 mitogen-activated protein kinase (MAPK), but not extracellular signal-regulated kinase. N-acetylcysteine that downregulated TNF-alpha-induced reactive oxygen species (ROS) inhibited JNK activation, but not p38 MAPK. N-acetylcysteine, SP600125 (JNK inhibitor) and SB203580 (p38 MAPK inhibitor) attenuated TNF-alpha-induced DNA-binding activities of both AP-1 and NF-kappaB. MPA inhibited JNK and p38 MAPK activations as well as ROS generation. N-acetylcysteine, SP600125, SB203580 and MPA had no effect on either TNF-alpha-induced IkappaBalpha degradation or p65 nuclear translocation, but attenuated p65 Ser276 phosphorylation.

CONCLUSION

MPA attenuated TNF-alpha-induced ET-1 production through inhibitions of ROS-dependent JNK and ROS-independent p38 MAPK that regulated NF-kappaB as well as AP-1. These findings suggest that MPA could have an effect of amelioration of atherosclerosis.

Premature vascular damage in systemic lupus erythematosus: an imbalance of damage and repair?

Systemic lupus erythematosus (SLE) is associated with an increase in the risk of premature cardiovascular complications caused by accelerated atherosclerosis, which significantly contributes to morbidity and mortality. Standard Framingham risk factors seem to be less important predictors of cardiovascular events than the presence of active SLE, and the immune dysregulation characteristic of lupus seems to play a dominant role in atherogenesis. Although both SLE-specific and nonspecific mechanisms have been proposed to play a prominent role in the induction of premature vascular damage in this disease, the exact etiology remains unclear. This review summarizes some of the proposed mechanisms that may promote accelerated vascular damage in lupus and explores potential targets for cardiovascular risk prevention in this patient population.