Targeting cardiovascular risk in rheumatoid arthritis: a dual role for statins

Identification of lipid-modifying drug targets for autoimmune diseases: insights from drug target mendelian randomization

BACKGROUNDS

A growing body of evidence has highlighted the interactions of lipids metabolism and immune regulation. Nevertheless, there is still a lack of evidence regarding the causality between lipids and autoimmune diseases (ADs), as well as their possibility as drug targets for ADs.

OBJECTIVES

This study was conducted to comprehensively understand the casual associations between lipid traits and ADs, and evaluate the therapeutic possibility of lipid-lowering drug targets on ADs.

METHODS

Genetic variants for lipid traits and variants encoding targets of various lipid-lowering drugs were derived from Global Lipid Genetics Consortium (GLGC) and verified in Drug Bank. Summary data of ADs were obtained from MRC Integrative Epidemiology Unit (MER-IEU) database and FinnGen consortium, respectively. The causal inferences between lipid traits/genetic agents of lipid-lowering targets and ADs were evaluated by Mendelian randomization (MR), summary data-based MR (SMR), and multivariable MR (MVMR) analyses. Enrichment analysis and protein interaction network were employed to reveal the functional characteristics and biological relevance of potential therapeutic lipid-lowering targets.

RESULTS

There was no evidence of causal effects regarding 5 lipid traits and 9 lipid-lowering drug targets on ADs. Genetically proxied 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR) inhibition was associated with a reduced risk of rheumatoid arthritis (RA) in both discovery (OR [odds ratio] = 0.45, 95%CI: 0.32, 0.63, P = 6.79 × 10- 06) and replicate datasets (OR = 0.37, 95%CI: 0.23, 0.61, P = 7.81 × 10- 05). SMR analyses supported that genetically proxied HMGCR inhibition had causal effects on RA in whole blood (OR = 0.48, 95%CI: 0.29, 0.82, P = 6.86 × 10- 03) and skeletal muscle sites (OR = 0.75, 95%CI: 0.56, 0.99, P = 4.48 × 10- 02). After controlling for blood pressure, body mass index (BMI), smoking and drinking alchohol, HMGCR suppression showed a direct causal effect on a lower risk of RA (OR = 0.33, 95%CI: 0.40, 0.96, P = 0.042).

CONCLUSIONS

Our study reveals causal links of genetically proxied HMGCR inhibition (lipid-lowering drug targets) and HMGCR expression inhibition with a decreased risk of RA, suggesting that HMGCR may serve as candidate drug targets for the treatment and prevention of RA.

Changes in the cholesterol profile of patients with rheumatoid arthritis treated with biologics or Janus kinase inhibitors

Objective

To assess the effects of biological and targeted synthetic disease-modifying antirheumatic drugs (DMARDs) on lipid profiles in patients with moderate-to-severe rheumatoid arthritis (RA).

Methods

This retrospective single-center observational study included patients with RA taking a tumor necrosis factor-α inhibitor (TNFi), abatacept, tocilizumab, or a Janus kinase inhibitor (JAKi) for at least 6 months. Changes in lipid profile were assessed at 6 months after the start of treatment, and associations between changes in lipid profiles and clinical efficacy, concomitant medications, and comorbidities were evaluated.

Results

This study included 114 patients treated with TNFi, 81 with abatacept, 103 with tocilizumab, and 89 with JAKi. The mean percentage change (from baseline to 6 months) in total cholesterol, low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), and non-HDL-C levels was higher in those taking tocilizumab and JAKi than in those taking TNFi and abatacept. A significant change in non-HDL-C was associated with JAKi (versus TNFi odds ratio [OR], 3.228; 95% confidence interval [CI], 1.536~6.785), tocilizumab (versus TNFi OR, 2.203; 95% CI, 1.035~4.689), and statins (OR, 0.487; 95% CI, 0.231~1.024). However, changes in disease activity in 28 joints were not associated with a significant change in non-HDL-C.

Conclusion

Tocilizumab- and JAKi-associated increases in serum non-HDL-C levels were observed regardless of changes in disease activity. Statins are recommended for RA patients showing a significant increase in cholesterol levels after initiating biological and targeted synthetic DMARDs.

Lipid metabolism in regulation of B cell development and autoimmunity

B cells play an important role in adaptive immunity and participate in the process of humoral immunity mainly by secreting antibodies. The entire development and differentiation process of B cells occurs in multiple microenvironments and is regulated by a variety of environmental factors and immune signals. Differentiation biases or disfunction of B cells participate in the process of many autoimmune diseases. Emerging studies report the impact of altered metabolism in B cell biology, including lipid metabolism. Here, we discuss how extracellular lipid environment and metabolites, membrane lipid-related components, and lipid synthesis and catabolism programs coordinate B cell biology and describe the crosstalk of lipid metabolic programs with signal transduction pathways and transcription factors. We conclude with a summary of therapeutic targets for B cell lipid metabolism and signaling in autoimmune diseases and discuss important future directions.

Effect of statin therapy on the prevention of new-onset acute coronary syndrome in patients with rheumatoid arthritis

BACKGROUND

The aim of this study is to investigate whether statin therapy can reduce new-onset acute coronary syndrome (ACS) in patients with rheumatoid arthritis (RA).

METHODS

We used a database from the Registry for Catastrophic Illness from the National Health Research Institute (NHRI) in Taiwan. All RA patients aged 18 or older, diagnosed between 1995 and 2013, without previous cardiovascular events were included. We divided participants into quartiles according to the accumulated statin equivalent dosage and tertiles of period of days of statin treatment to examine the possible dose-response effect. To avoid confounding effects, a 1:4 propensity score matching and Cox's proportional hazard regression models were applied to estimate the hazard ratios for ACS events in patients with and without statin use.

RESULTS

Total 49,227 patients were included and PS matching identified 5483 patients receiving statins and 21,932 who did not. RA patients treated with statins had lower incidence of first ACS event (IRR 0.779, 95% CI: 0.654-0.927, p=0.005) after PS matching. Statin therapy is associated with reduced risk of new ACS before PS matching (HR=0.847, 95% CI: 0.737-0.973, p=0.019) and the beneficial effect is correlated with accumulated dose and therapy duration (HRs from Q1 to Q4 are 1.215, 0.825, 0.716 and 0.611, p<0.001 for trend; HRs from T1 to T3 are 1.100, 0.841 and 0.611, p<0.001 for trend). These results remained robust after propensity matching. Comparison between 6 different statins, rosuvastatin seems to be associated with better outcome on ACS primary prevention after excluding participants taking more than one kind of statin.

CONCLUSIONS

Our study demonstrated that statin therapy is associated with lower event rate of new-onset ACS in RA patients and the beneficial effect is dose-responsive.

Differential changes in the pharmacokinetics of statins in collagen-induced arthritis rats

The elevated systemic levels of cytokines in rheumatoid arthritis (RA) can change the expression of metabolic enzymes and transporters. Given that statins are lipid-lowering agents frequently used in RA patients with concurrent cardiovascular diseases, the objective of the present study was to investigate the impacts of RA on the pharmacokinetics of statins of different disposition properties in rats with collagen-induced arthritis (CIA). The expression of metabolic enzymes and transporters in tissues of CIA rats were analyzed by RT-qPCR. Statins were given to CIA rats and controls through different routes, respectively. Blood samples were collected and analyzed by UPLC/MS/MS. Isolated microsomes and hepatocytes were used to determine the metabolic and uptake clearance of statins. The results showed that, compared with controls, the mRNA levels of intestinal Cyp3a1 and hepatic Cyp2c6, Cyp2c7, Cyp3a1, Oatp1a1, Oatp1b2, Oatp1a4, and Mrp2 were markedly decreased in the CIA rats. The maximal metabolic activities of Cyp2c and Cyp3a were reduced in liver microsomes of CIA rats. When given orally or injected through hepatic portal vein, the systemic levels of fluvastatin, simvastatin, and atorvastatin, but not of rosuvastatin and pravastatin, were increased in CIA rats. The metabolic clearance of simvastatin and hepatic uptake clearance of fluvastatin and atorvastatin were decreased in CIA rats. These findings suggest that the changes in the expression of enzymes and/or transporters in CIA rats differentially affect the pharmacokinetics of statins.

Major involvement of bacterial components in rheumatoid arthritis and its accompanying oxidative stress, systemic inflammation and hypercoagulability

We review the evidence that infectious agents, including those that become dormant within the host, have a major role to play in much of the etiology of rheumatoid arthritis and the inflammation that is its hallmark. This occurs in particular because they can produce cross-reactive (auto-)antigens, as well as potent inflammagens such as lipopolysaccharide that can themselves catalyze further inflammagenesis, including via β-amyloid formation. A series of observables coexist in many chronic, inflammatory diseases as well as rheumatoid arthritis. They include iron dysregulation, hypercoagulability, anomalous morphologies of host erythrocytes, and microparticle formation. Iron dysregulation may be responsible for the periodic regrowth and resuscitation of the dormant bacteria, with concomitant inflammagen production. The present systems biology analysis benefits from the philosophical idea of "coherence," that reflects the principle that if a series of ostensibly unrelated findings are brought together into a self-consistent narrative, that narrative is thereby strengthened. As such, we provide a coherent and testable narrative for the major involvement of (often dormant) bacteria in rheumatoid arthritis.

[Interleukin-6 inhibition and cardiovascular disease in patients with rheumatoid arthritis]

Rheumatoid arthritis (RA) is a' disease conferring high risk for cardiovascular events (CVE). Systemic inflammation underlying RA favors development of CVE. The safety of biological agents, acting on the cardiovascular system has been inadequately investigated. On the one hand, they decrease RA activity and, on the other, may increase the risk of CVE. This review analyzes' the literature data predominantly published in recent years on the effect of an IL-6 receptor inhibitor on the cardiovascular system. Tocilizumab is shown to be a promising agent to reduce cardiovascular risk the findings need to be clinically verified. Long-term prospective investigations should be conducted to determine more exactly the impact of IL-6 receptor inhibition on. the development of CVE.

The simultaneous occurrence of both hypercoagulability and hypofibrinolysis in blood and serum during systemic inflammation, and the roles of iron and fibrin(ogen)

Although the two phenomena are usually studied separately, we summarise a considerable body of literature to the effect that a great many diseases involve (or are accompanied by) both an increased tendency for blood to clot (hypercoagulability) and the resistance of the clots so formed (hypofibrinolysis) to the typical, 'healthy' or physiological lysis. We concentrate here on the terminal stages of fibrin formation from fibrinogen, as catalysed by thrombin. Hypercoagulability goes hand in hand with inflammation, and is strongly influenced by the fibrinogen concentration (and vice versa); this can be mediated via interleukin-6. Poorly liganded iron is a significant feature of inflammatory diseases, and hypofibrinolysis may change as a result of changes in the structure and morphology of the clot, which may be mimicked in vitro, and may be caused in vivo, by the presence of unliganded iron interacting with fibrin(ogen) during clot formation. Many of these phenomena are probably caused by electrostatic changes in the iron-fibrinogen system, though hydroxyl radical (OH˙) formation can also contribute under both acute and (more especially) chronic conditions. Many substances are known to affect the nature of fibrin polymerised from fibrinogen, such that this might be seen as a kind of bellwether for human or plasma health. Overall, our analysis demonstrates the commonalities underpinning a variety of pathologies as seen in both hypercoagulability and hypofibrinolysis, and offers opportunities for both diagnostics and therapies.

Cardiovascular disease in patients with chronic inflammation: mechanisms underlying premature cardiovascular events in rheumatologic conditions

A variety of systemic inflammatory rheumatic diseases associate with an increased risk of atherosclerotic events and premature cardiovascular (CV) disease. Although this recognition has stimulated intense basic science and clinical research, the precise nature of the relationship between local and systemic inflammation, their interactions with traditional CV risk factors, and their role in accelerating atherogenesis remains unresolved. The individual rheumatic diseases have both shared and unique attributes that might impact CV events. Understanding of the positive and negative influences of individual anti-inflammatory therapies remains rudimentary. Clinicians need to adopt an evidence-based approach to develop diagnostic techniques to identify those rheumatologic patients most at risk of CV disease and to develop effective treatment protocols. Development of optimal preventative and disease-modifying approaches for atherosclerosis in these patients will require close collaboration between basic scientists, CV specialists, and rheumatologists. This interface presents a complex, important, and exciting challenge.

Altered lipidome and antioxidative activity of small, dense HDL in normolipidemic rheumatoid arthritis: relevance of inflammation

OBJECTIVE

High-density lipoprotein (HDL) particles exert potent antiatherogenic activities, including antioxidative actions, which are relevant to attenuation of atherosclerosis progression. Such activities are enriched in small, dense HDL and can be compromised under conditions of chronic inflammation like rheumatoid arthritis (RA). However, structure-function relationships of HDL largely remain indeterminate.

METHODS

The relationships between HDL structure and function were evaluated in normolipidemic patients with active RA (DAS28 > 3.2; n = 12) and in normolipidemic age-matched controls (n = 10). Small, dense HDL3b and 3c particles were isolated from plasma or serum by density gradient ultracentrifugation and their physicochemical characteristics, lipidome (by LC/MS/MS) and antioxidative function (as protection of normolipidemic LDL from free radical-induced oxidation) were evaluated.

RESULTS

As expected, active RA patients featured significantly elevated plasma levels of high-sensitivity C-reactive protein (hsCRP; p < 0.001) and serum amyloid A (SAA; p < 0.01) relative to controls. Antioxidative activity and weight % chemical composition of small, dense HDL did not differ between RA patients and controls (p > 0.05), whereas HDL phosphosphingolipidome was significantly altered in RA. Subgroup analyses revealed that RA patients featuring high levels of inflammation (hsCRP>10 mg/l) possessed small, dense HDL with reduced antioxidative activities (p < 0.01). Furthermore, antioxidative activity of HDL was inversely correlated with plasma hsCRP (p < 0.01).

CONCLUSIONS

These data revealed that (i) despite normolipidemic state, the lipidome of small, dense HDL was altered in RA and (ii) high levels of inflammation can be responsible for the functional deficiency of small, dense HDL in RA.

Immune activation and collateral damage in AIDS pathogenesis

In the past decade, evidence has accumulated that human immunodeficiency virus (HIV)-induced chronic immune activation drives progression to AIDS. Studies among different monkey species have shown that the difference between pathological and non-pathological infection is determined by the response of the immune system to the virus, rather than its cytopathicity. Here we review the current understanding of the various mechanisms driving chronic immune activation in HIV infection, the cell types involved, its effects on HIV-specific immunity, and how persistent inflammation may cause AIDS and the wide spectrum of non-AIDS related pathology. We argue that therapeutic relief of inflammation may be beneficial to delay HIV-disease progression and to reduce non-AIDS related pathological side effects of HIV-induced chronic immune stimulation.

Cardiovascular risk in rheumatoid arthritis and systemic autoimmune rheumatic disorders: a suggested model of preventive strategy

The pathogenesis of accelerated cardiovascular damage commonly characterizing patients affected by systemic chronic inflammatory and autoimmune rheumatic disorders is quite complex and still not fully clarified. However, it is well accepted that a strong relationship between multiple factors, including both traditional cardiovascular risk factors and disease-related inflammatory and autoimmune mechanisms, may in part explain the precocious atherosclerotic vessel damage and the increased incidence of cardiovascular events. Nevertheless, although several recent studies focused their attention on the investigation of these complex mechanisms, data regarding possible preventive strategies aimed to reduce long-term cardiovascular risk in these subjects are still lacking and not conclusive. In this setting, the early introduction of evidence-based preventive measures for the correct management of patients with systemic autoimmune disorders would be of extreme importance to reduce subclinical atherosclerosis incidence and possible major cardiovascular events.

Treatment to lipid targets in patients with inflammatory joint diseases in a preventive cardio-rheuma clinic

OBJECTIVES

To perform cardiovascular risk stratification in patients with inflammatory joint diseases (IJD) and treat to lipid targets according to recommendations.

METHODS

We initiated a preventive cardio-rheuma clinic based on the unmet need of adequate cardiovascular prevention in IJD patients. A full cardiovascular risk stratification was performed at the first consultation (history of conventional risk factors and of cardiovascular disease, lipid measurement, blood pressure and ultrasound examination of both carotid arteries), and the patient was classified to either a primary or secondary cardiovascular prevention regime, or to have a low risk (no intervention). Lipid-lowering treatment was adjusted until at least two lipid targets were achieved.

RESULTS

Of the 426 patients referred, 36.6% had a systematic coronary risk evaluation less than 5% (no lipid-lowering intervention). The remaining 270 patients ((rheumatoid arthritis (RA), n=165; ankylosing spondylitis (AS), n=70; and psoriatic arthritis (PsA), n=35) were assigned to either primary (n=63) or secondary prevention (n=207). There were significant differences between the patient groups regarding age (p<0.001), sex (p<0.001) and disease duration (p<0.001). Lipid changes in IJD patients were: total cholesterol -1.86±1.20 mmol/l (p<0.001); low-density lipoprotein cholesterol -1.74±1.11 (p<0.001); high-density lipoprotein cholesterol 0.01±0.30 (p=0.61); triglycerides -0.28±0.72 (p<0.001). The proportions of patients reaching at least two lipid targets were for RA 92.1%, AS 90.0% and PsA 82.9%. No serious adverse events were observed.

CONCLUSIONS

There was indication for cardiovascular prevention in a high proportion of IJD patients referred for cardiovascular risk stratification. Treatment to lipid targets was successful in approximately 90% of patients with IJD.

HMG-CoA reductase inhibitors enhance phagocytosis by upregulating ATP-binding cassette transporter A7

We recently reported that the endogenous ATP-binding cassette transporter (ABC) A7 strongly associates with phagocytosis, being regulated by sterol regulatory element binding protein 2. We therefore examined the effect of statins on phagocytosis in vitro and in vivo through the SREBP-ABCA7. Phagocytosis was found to be enhanced by pravastatin, rosuvastatin and simvastatin and cyclodextrin in J774 macrophages, as cellular cholesterol was reduced and expressions of the cholesterol-related genes were modulated, including an increase of ABCA7 mRNA and decrease of ABCA1 mRNA. Conversely, knock-down of ABCA7 expression by siRNA ablated enhancement of phagocytosis by statins. In vivo, pravastatin enhanced phagocytosis in wild-type mice, but not in ABCA7-knockout mice. We thus concluded that statins enhance phagocytosis through the SREBP-ABCA7 pathway. These findings provide a molecular basis for enhancement of the host-defense system by statins showing that one of their "pleiotropic" effects is in fact achieved through their reaction to a primary target.

Lipid paradox in rheumatoid arthritis: the impact of serum lipid measures and systemic inflammation on the risk of cardiovascular disease

OBJECTIVE

To examine the impact of systemic inflammation and serum lipids on cardiovascular disease (CVD) in rheumatoid arthritis (RA).

METHODS

In a population-based RA incident cohort (1987 American College of Rheumatology criteria first met between 1988 and 2007), details were collected of serum lipid measures, erythrocyte sedimentation rates (ESRs), C-reactive protein (CRP) measures and cardiovascular events, including ischaemic heart disease and heart failure. Cox models were used to examine the association of lipids and inflammation with the risk of CVD and mortality, adjusting for age, sex and year of RA incidence.

RESULTS

The study included 651 patients with RA (mean age 55.8 years, 69% female); 67% were rheumatoid factor positive. ESR was associated with the risk of CVD (HR=1.2 per 10 mm/h increase, 95% CI 1.1 to 1.3). Similar findings, although not statistically significant, were seen with CRP (p=0.07). A significant non-linear association for total cholesterol (TCh) with risk of CVD was found, with 3.3-fold increased risk for TCh <4 mmol/l (95% CI 1.5 to 7.2) and no increased risk of CVD for TCh ≥4 mmol/l (p=0.57). Low low-density lipoprotein cholesterol (LDL <2 mmol/l) was associated with marginally increased risk of CVD (p=0.10); there was no increased risk for LDL ≥2 mmol/l (p=0.76).

CONCLUSION

Inflammatory measures (particularly, ESR) are significantly associated with the risk of CVD in RA. Lipids may have paradoxical associations with the risk of CVD in RA, whereby lower TCh and LDL levels are associated with increased cardiovascular risk.

Effects of simvastatin on the function of dendritic cells in patients with rheumatic arthritis

The present study examined the functional profile of dendritic cells (DCs) in patients with rheumatoid arthritis (RA) and the effects of simvastatin on the function of DCs. A total of 40 patients who was recently diagnosed as having RA were equally assigned to two groups: the routine treatment group (group R) and the routine treatment plus simvastatin group (group R+S). Twenty healthy individuals served as control. The peripheral blood mononuclear cells (PBMCs) were isolated before and 4 weeks after the treatment and then cultured with interleukin-4 (IL-4) and granulocyte-macrophage colony stimulatory factor (GM-CSF) to prepare mature DCs. The expression of co-stimulating factor CD86 on the surface of DCs was assessed by flow cytometry. And the stimulating capacity of DCs was measured by mixed lymphocyte reaction (MLR). The contents of cytokines in culture supernatants of DCs in MLR were detected by ELISA. Blood lipids and high-sensitivity C-reactive protein (hs-CRP) were detected. The relationship between the expression of CD86 and the blood CRP level was also investigated. The results showed that, as compared with the control group, the CD86 expression and the level of cytokines secreted by DCs were significantly increased in RA patients and greater stimulating capacity of DCs in MLR was demonstrated in RA patients. T lymphocytes in MLR secreted higher levels of proinflammatory cytokines (IL-2, IL-17, TNF-α and INF-γ) and lower level of anti-inflammation cytokine (IL-10). The function of DCs was markedly weakened and the level of hs-CRP and low-density lipoprotein was substantially lowered in group R+S in comparison to group R. The CD86 expression was positively correlated with hs-CRP. It was concluded that DCs in RA are highly activated and DC-initiated immune reaction may play an important role in the pathogenesis of RA. Simvastatin administration can significantly inhibit the DCs function and reduce the level of hs-CRP, indicating the suppression on inflammatory reaction may be one of the mechanisms by which simvastatin exerts its effect in treating RA.

Atherosclerotic vascular damage and rheumatoid arthritis: a complex but intriguing link

Rheumatoid arthritis is a chronic inflammatory disease characterized by a reduced life expectancy mainly due to cardiovascular disease. In long-standing disease, it has been widely demonstrated that both traditional cardiovascular risk and disease-related factors, including chronic inflammation and immune-mediated mechanisms, play a key role in accelerating atherosclerotic damage of the arterial wall. The short- and long-term effects of immunosuppressive treatment on cardiovascular disease outcome is, however, uncertain and a multidisciplinary approach appears to represent the best management of cardiovascular risk in these patients.