p53 is required for chloroquine-induced atheroprotection but not insulin sensitization

Hospitalization after hydroxychloroquine initiation in patients with heart failure with preserved ejection fraction and autoimmune disease

BACKGROUND

Hydroxychloroquine (HCQ) reduces cardiovascular events among patients with autoimmune disorders and is being evaluated as a therapeutic option for populations with high-risk cardiovascular disease. However, recent studies have raised concerns about HCQ use and cardiovascular events.

OBJECTIVE

To assess the association of HCQ initiation with heart failure-related and all-cause hospitalizations among patients with heart failure and preserved ejection fraction (HFpEF).

METHODS

We conducted a cohort study of patients aged ≥18 years with diagnosed HFpEF and autoimmune disease using MarketScan Commercial and Medicare Supplemental databases (2007-2019). Patients were required to initiate HCQ after their first HFpEF diagnosis (HCQ users) or not (HCQ nonusers). For the patients in the HCQ users group, the first HCQ prescription date was assigned as the index date. Index date for the HCQ nonuser group was assigned by prescription-time distribution matching HCQ users, by utilizing the number of days from HFpEF diagnosis to the first HCQ prescription. After 1:≥3 propensity score (PS) matching, Cox proportional hazards regression models were used to compare HF-related and all-cause hospitalizations between users and nonusers.

RESULTS

After PS matching, 2229 patients (592 HCQ users and 1637 HCQ nonusers) were included. After controlling for covariates, patients who received HCQ had lower risks of HF-related hospitalization (adjusted hazard ratio, 0.44; 95% CI, 0.24-0.82) and all-cause hospitalization (adjusted hazard ratio, 0.69; 95% CI, 0.57-0.83) compared with patients not using HCQ.

CONCLUSIONS

Among patients with HFpEF and autoimmune disease, initiation of HCQ use was associated with a decreased risk of HF-related and all-cause hospitalizations.

Chloroquine Alleviates Atherosclerosis by Modulating Regulatory T Cells Through the ATM/AMPK/mTOR Signaling Pathway in ApoE -/- Mice

BACKGROUND

Clinical observation suggests the atheroprotective effect of chloroquine and its derivatives, while its mechanism remains unclear. This study aimed to observe the protective effect of chloroquine against atherosclerosis and explore the underlying mechanism.

METHODS

Ataxia telangiectasia mutated (ATM) wild-type or haploinsufficient apolipoprotein-E-knockout (ATM+/+ApoE-/- or ATM+/-ApoE-/-) mice were treated with different dosages of chloroquine. Anti-CD25 antibody was used to deplete natural Tregs in ATM+/+ApoE-/- mice. The atherosclerotic burden in different groups of mice was comprehensively evaluated by H&E staining and Masson staining. The effect of chloroquine on the regulatory T cells (Tregs) was assessed in vivo and in vitro by flow cytometry and immunohistochemical staining. The expression of related proteins was detected by real-time polymerase chain reaction and western blotting.

RESULTS

In ATM+/+ApoE-/- mice, chloroquine alleviated atherosclerotic lesions, stabilized the plaque, and increased Treg counts in the atherosclerotic lesions and spleens. However, in ATM haploinsufficient mice (ATM+/-ApoE-/-), chloroquine no longer prevented atherosclerosis or impacted Treg counts. Abolishing Treg cells using an anti-CD25 antibody in vivo abrogated the atheroprotective effect of chloroquine. In vitro, chloroquine promoted the differentiation of Tregs from naïve T cells, which was accompanied by enhanced ATM/AMP-activated protein kinase (AMPK) activity and reduced downstream mammalian target of rapamycin (mTOR) activity.

DISCUSSION

These findings suggest that chloroquine ameliorates atherosclerosis and stabilizes plaque by modulating Tregs differentiation through the regulation of the ATM/AMPK/mTOR pathway.

Management of Cardiovascular Disease in Kidney Disease Study: Rationale and Design

INTRODUCTION

Atherosclerosis, inflammation, and vascular stiffness are prominent interrelated risk factors contributing to the high incidence of cardiovascular disease (CVD) in patients with CKD. Conventional CVD management strategies in CKD largely target atherosclerotic CVD and have had a limited impact on the cardiovascular mortality in this population. Multiple in vivo and in vitro studies and epidemiological evidence from the rheumatologic cohorts have shown that low-dose hydroxychloroquine has beneficial effects on inflammation, endothelial function, insulin sensitivity, and metabolic syndrome. Our recent proof-of-concept animal study showed that hydroxychloroquine has marked protection against atherosclerosis and vascular stiffness. We hypothesize that hydroxychloroquine has the potential to provide significant cardiovascular benefits in patients with CKD.

METHODS

The Management of Cardiovascular disease in Kidney disease study (NCT03636152) is a phase 2B, randomized, double-blind, placebo-controlled trial evaluating the effects of low-dose hydroxychloroquine therapy on the parameters of atherosclerosis, inflammation, and vascular stiffness in patients with CKD. The study plans to enroll 100 CKD patients estimated to be at high cardiovascular risk by a combination of low estimated glomerular filtration rate and albuminuria and treat them for 18 months with hydroxychloroquine or placebo in 1:1 allocation.

RESULTS

The study will assess the change in the total carotid plaque volume as measured by serial noncontrast carotid MRI as the primary outcome and the serial changes in plasma inflammation markers, vascular stiffness, renal function, and the composition characteristics of the carotid plaque as secondary outcome measures.

DISCUSSION/CONCLUSION

The results of this trial will provide the proof-of-applicability for hydroxychloroquine in the CVD in CKD. If positive, this trial should lead to phase-3 trials with clinical end points for this potentially transformative, novel, and inexpensive therapy for CVD in CKD.

Chronic inflammatory diseases, myocardial function and cardioprotection

The association between chronic inflammatory diseases (CIDs) and increased cardiovascular (CV) risk is well documented and can be a most threatening complication in these patients. However, the pathogenetic mechanisms underlying increased CV risk remain elusive, especially in their cellular and biochemical pathways. Using animal models to understand mechanisms underlying cardiac involvement are limited. Additionally, treatments may influence cardiovascular events through different outcomes. Some drugs used to treat CIDs can negatively affect cardiac function by a direct toxicity, whereas others may protect the myocardium. In the present article, we focus on the cardiac manifestations and risk factors, the pathogenetic mechanisms, and the effect of treatments on myocardial function and cardioprotection for five common worldwide CIDs (rheumatoid arthritis, systemic lupus erythematosus, systemic sclerosis, psoriasis and inflammatory bowel disease). We also give recommendations in order to evaluate common targets between CID and CV disease (CVD) and to design therapies to alleviate CID-related CVD. LINKED ARTICLES: This article is part of a themed issue on Risk factors, comorbidities, and comedications in cardioprotection. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v177.23/issuetoc.

Candidate SNP Markers of Atherogenesis Significantly Shifting the Affinity of TATA-Binding Protein for Human Gene Promoters show stabilizing Natural Selection as a Sum of Neutral Drift Accelerating Atherogenesis and Directional Natural Selection Slowing It

(1) Background: The World Health Organization (WHO) regards atherosclerosis-related myocardial infarction and stroke as the main causes of death in humans. Susceptibility to atherogenesis-associated diseases is caused by single-nucleotide polymorphisms (SNPs). (2) Methods: Using our previously developed public web-service SNP_TATA_Comparator, we estimated statistical significance of the SNP-caused alterations in TATA-binding protein (TBP) binding affinity for 70 bp proximal promoter regions of the human genes clinically associated with diseases syntonic or dystonic with atherogenesis. Additionally, we did the same for several genes related to the maintenance of mitochondrial genome integrity, according to present-day active research aimed at retarding atherogenesis. (3) Results: In dbSNP, we found 1186 SNPs altering such affinity to the same extent as clinical SNP markers do (as estimated). Particularly, clinical SNP marker rs2276109 can prevent autoimmune diseases via reduced TBP affinity for the human MMP12 gene promoter and therefore macrophage elastase deficiency, which is a well-known physiological marker of accelerated atherogenesis that could be retarded nutritionally using dairy fermented by lactobacilli. (4) Conclusions: Our results uncovered SNPs near clinical SNP markers as the basis of neutral drift accelerating atherogenesis and SNPs of genes encoding proteins related to mitochondrial genome integrity and microRNA genes associated with instability of the atherosclerotic plaque as a basis of directional natural selection slowing atherogenesis. Their sum may be stabilizing the natural selection that sets the normal level of atherogenesis.

Expanding horizons for clinical applications of chloroquine, hydroxychloroquine, and related structural analogues

Several experimental and clinical studies have transformed the traditional antimalarial role of chloroquine (CHQ) and related structural analogues to potent therapeutic agents for a host of nonmalarial indications. The expanding clinical applicability for these drugs includes rheumatological and cardiovascular disorders (CVD), chronic kidney disease (CKD), oncology, and a variety of nonmalarial infections. These clinical advancements are primarily related to pleiotropic pharmacological actions of these drugs, including immunomodulation, anti-inflammatory properties, and capabilities of inducing autophagy and apoptosis at a cellular level. Historically, many clinical benefits in nonmalarial indications were first recognized through serendipitous observations; however, with numerous ongoing systematic clinical studies, the clinical horizons of these drugs have a promising future.

Low dose chloroquine decreases insulin resistance in human metabolic syndrome but does not reduce carotid intima-media thickness

BACKGROUND

Metabolic syndrome, an obesity-related condition associated with insulin resistance and low-grade inflammation, leads to diabetes, cardiovascular diseases, cancer, osteoarthritis, and other disorders. Optimal therapy is unknown. The antimalarial drug chloroquine activates the kinase ataxia telangiectasia mutated (ATM), improves metabolic syndrome and reduces atherosclerosis in mice. To translate this observation to humans, we conducted two clinical trials of chloroquine in people with the metabolic syndrome.

METHODS

Eligibility included adults with at least 3 criteria of metabolic syndrome but who did not have diabetes. Subjects were studied in the setting of a single academic health center. The specific hypothesis: chloroquine improves insulin sensitivity and decreases atherosclerosis. In Trial 1, the intervention was chloroquine dose escalations in 3-week intervals followed by hyperinsulinemic euglycemic clamps. Trial 2 was a parallel design randomized clinical trial, and the intervention was chloroquine, 80 mg/day, or placebo for 1 year. The primary outcomes were clamp determined-insulin sensitivity for Trial 1, and carotid intima-media thickness (CIMT) for Trial 2. For Trial 2, subjects were allocated based on a randomization sequence using a protocol in blocks of 8. Participants, care givers, and those assessing outcomes were blinded to group assignment.

RESULTS

For Trial 1, 25 patients were studied. Chloroquine increased hepatic insulin sensitivity without affecting glucose disposal, and improved serum lipids. For Trial 2, 116 patients were randomized, 59 to chloroquine (56 analyzed) and 57 to placebo (51 analyzed). Chloroquine had no effect on CIMT or carotid contrast enhancement by MRI, a pre-specified secondary outcome. The pre-specified secondary outcomes of blood pressure, lipids, and activation of JNK (a stress kinase implicated in diabetes and atherosclerosis) were decreased by chloroquine. Adverse events were similar between groups.

CONCLUSIONS

These findings suggest that low dose chloroquine, which improves the metabolic syndrome through ATM-dependent mechanisms in mice, modestly improves components of the metabolic syndrome in humans but is unlikely to be clinically useful in this setting.Trial registration ClinicalTrials.gov (NCT00455325, NCT00455403), both posted 03 April 2007.

Revisiting the Cardiotoxic Effect of Chloroquine

PURPOSE

Cardiotoxicity is a well-known side effect of chloroquine. Several studies have proposed chloroquine as a potential anti-diabetic treatment but do not address this problem. The current study investigated the effect of ex vivo chloroquine treatment on (1) heart function and glucose uptake, (2) mitochondrial function and (3) in vivo treatment on heart function.

METHODS

Control or obese male Wistar rats were used throughout. Dose responses of increasing chloroquine concentrations versus vehicle on cardiac function were measured using isolated, Langendorff-perfused hearts whilst glucose uptake and cell viability were determined in ventricular cardiomyocytes. Mitochondrial function was assessed with a Clark-type oxygraph (Hansatech) after ex vivo perfusion with 30 μM chloroquine versus vehicle. Animals were treated orally with 5 mg/kg/day chloroquine for 6 weeks.

RESULTS

Acute chloroquine treatment of 10 μM was sufficient to significantly decrease heart function (p < 0.05) whilst 30 μM significantly reduced heart rate (p < 0.05). Chloroquine became toxic to isolated cardiomyocytes at high concentrations (100 μM), and had no effect on cardiomyocyte glucose uptake. Ex vivo treatment did not affect mitochondrial function, but chronic low-dose in vivo chloroquine treatment significantly decreased aortic output and total work in hearts (p < 0.005).

CONCLUSION

Low and intermediate chloroquine doses administered either chronically or acutely are sufficient to result in myocardial dysfunction.

Defective Autophagy in T Cells Impairs the Development of Diet-Induced Hepatic Steatosis and Atherosclerosis

Macroautophagy (or autophagy) is a conserved cellular process in which cytoplasmic cargo is targeted for lysosomal degradation. Autophagy is crucial for the functional integrity of different subsets of T cells in various developmental stages. Since atherosclerosis is an inflammatory disease of the vessel wall which is partly characterized by T cell mediated autoimmunity, we investigated how advanced atherosclerotic lesions develop in mice with T cells that lack autophagy-related protein 7 (Atg7), a protein required for functional autophagy. Mice with a T cell-specific knock-out of Atg7 (Lck-Cre Atg7^f/f) had a diminished naïve CD4⁺ and CD8⁺ T cell compartment in the spleen and mediastinal lymph node as compared to littermate controls (Atg7^f/f). Lck-Cre Atg7^f/f and Atg7^f/f mice were injected intravenously with rAAV2/8-D377Y-mPCSK9 and fed a Western-type diet to induce atherosclerosis. While Lck-Cre Atg7^f/f mice had equal serum Proprotein Convertase Subtilisin/Kexin type 9 levels as compared to Atg7^f/f mice, serum cholesterol levels were significantly diminished in Lck-Cre Atg7^f/f mice. Histological analysis of the liver revealed less steatosis, and liver gene expression profiling showed decreased expression of genes associated with hepatic steatosis in Lck-Cre Atg7^f/f mice as compared to Atg7^f/f mice. The level of hepatic CD4⁺ and CD8⁺ T cells was greatly diminished but both CD4⁺ and CD8⁺ T cells showed a relative increase in their IFNγ and IL-17 production upon Atg7 deficiency. Atg7 deficiency furthermore reduced the hepatic NKT cell population which was decreased to < 0.1% of the lymphocyte population. Interestingly, T cell-specific knock-out of Atg7 decreased the mean atherosclerotic lesion size in the tri-valve area by over 50%. Taken together, T cell-specific deficiency of Atg7 resulted in a decrease in hepatic steatosis and limited inflammatory potency in the (naïve) T cell compartment in peripheral lymphoid tissues, which was associated with a strong reduction in experimental atherosclerosis.

Boosting ATM activity alleviates aging and extends lifespan in a mouse model of progeria

DNA damage accumulates with age (Lombard et al., 2005). However, whether and how robust DNA repair machinery promotes longevity is elusive. Here, we demonstrate that ATM-centered DNA damage response (DDR) progressively declines with senescence and age, while low dose of chloroquine (CQ) activates ATM, promotes DNA damage clearance, rescues age-related metabolic shift, and prolongs replicative lifespan. Molecularly, ATM phosphorylates SIRT6 deacetylase and thus prevents MDM2-mediated ubiquitination and proteasomal degradation. Extra copies of Sirt6 extend lifespan in Atm-/- mice, with restored metabolic homeostasis. Moreover, the treatment with CQ remarkably extends lifespan of Caenorhabditis elegans, but not the ATM-1 mutants. In a progeria mouse model with low DNA repair capacity, long-term administration of CQ ameliorates premature aging features and extends lifespan. Thus, our data highlights a pro-longevity role of ATM, for the first time establishing direct causal links between robust DNA repair machinery and longevity, and providing therapeutic strategy for progeria and age-related metabolic diseases.

As cells live and divide, their genetic material gets damaged. The DNA damage response is a network of proteins that monitor, recognize and fix the damage, which is also called DNA lesions. For example, an enzyme called ATM senses when DNA is broken and then begins a process that will get it repaired, while another enzyme known as SIRT6 participates in the actual mending process.

When organisms get older, the repair machinery becomes less efficient, and the number of DNA lesions and errors increases. The accumulation of DNA damage may cause the ‘symptoms’ of old age – from cancer, to wrinkles and the slowing down of the body’s chemical processes. In fact, individuals with defective ATMs (who thus struggle to repair their DNA) age abnormally fast; conversely, SIRT6 promotes longevity. If declining repair mechanisms cause aging, would boosting the DNA damage response slow down this process?

Chloroquine is a drug used to combat malaria, but it can also enhance the activity of ATM without damaging DNA. Qian, Liu et al. show that chloroquine helps cells remove broken DNA and keep dividing for longer. In animals, the drug increases the lifespan of worms and prolongs the lives of mice who have mutations that make them age quicker.

Qian, Liu et al. also demonstrate that ATM works by chemically altering the pro-longevity enzyme SIRT6. These changes make SIRT6 more stable, and keep it safe from cellular processes that destroy it. In addition, mice that are genetically engineered to lack ATM can survive for longer if they also produce extra SIRT6. These experiments show that enhancing the DNA damage response can slow down aging, thus linking the DNA repair machinery to longevity.

Progeria is a group of rare genetic conditions with inefficient DNA repair; people with progeria age fast and die young. The results by Qian, Liu et al., if confirmed in humans, could provide a new way of treating these diseases.

Cumulative immunosuppressant exposure is associated with diversified cancer risk among 14 832 patients with systemic lupus erythematosus: a nested case-control study

Objectives

Immunosuppressive therapy is necessary to alter the natural course of SLE. However, immunosuppressant-related cancer risk is a major concern. The aim of this study was to determine whether immunosuppressant use is associated with cancer risk in SLE.

Methods

We designed a retrospective nested case-control study within an SLE population based on the National Health Insurance Research Database in Taiwan. We screened 14 842 patients with SLE from 2001 to 2013 and compared patients with SLE complicated by later cancer with patients with SLE but without cancer. The cumulative dose of immunosuppressants was calculated from the SLE diagnosis date to the occurrence of cancer. The immunosuppressants of interest were AZA, CYC, MTX, HCQ and systemic glucocorticoids. Adjusted odds ratios (ORs) for cancer were calculated in conditional Cox regression models after propensity score matching.

Results

The top five types of cancers were breast (16.9%), haematological (11.7%), colorectal (11.0%), lung (10.6%) and hepatobiliary (10.4%) cancers. After matching, this study included 330 cancer patients and 1320 matched cancer-free patients. The adjusted analyses showed an association of a higher cumulative CYC dose (OR = 1.09, 95% CI: 1.04, 1.13) and lower HCQ dose (OR = 0.93, 95% CI: 0.90, 0.97) with cancer risk in comparison with the controls.

Conclusion

Diverse cancer risks are associated with different immunosuppressants in patients with SLE. CYC increases the risk of cancer, and HCQ decreases this risk in SLE patients, both in a dose-dependent manner.

Differential gene expression in human abdominal aortic aneurysm and aortic occlusive disease

Abdominal aortic aneurysm (AAA) and aortic occlusive disease (AOD) represent common causes of morbidity and mortality in elderly populations which were previously believed to have common aetiologies. The aim of this study was to assess the gene expression in human AAA and AOD. We performed microarrays using aortic specimen obtained from 20 patients with small AAAs (≤ 55mm), 29 patients with large AAAs (> 55mm), 9 AOD patients, and 10 control aortic specimens obtained from organ donors. Some differentially expressed genes were validated by quantitative-PCR (qRT-PCR)/immunohistochemistry. We identified 840 and 1,014 differentially expressed genes in small and large AAAs, respectively. Immune-related pathways including cytokine-cytokine receptor interaction and T-cell-receptor signalling were upregulated in both small and large AAAs. Examples of validated genes included CTLA4 (2.01-fold upregulated in small AAA, P = 0.002), NKTR (2.37-and 2.66-fold upregulated in small and large AAA with P = 0.041 and P = 0.015, respectively), and CD8A (2.57-fold upregulated in large AAA, P = 0.004). 1,765 differentially expressed genes were identified in AOD. Pathways upregulated in AOD included metabolic and oxidative phosphorylation categories. The UCP2 gene was downregulated in AOD (3.73-fold downregulated, validated P = 0.017). In conclusion, the AAA and AOD transcriptomes were very different suggesting that AAA and AOD have distinct pathogenic mechanisms.

Chloroquine increases phosphorylation of AMPK and Akt in myotubes

Aims

There are reports that ataxia telangiectasia mutated (ATM) can activate the AMP-activated protein kinase (AMPK) and also Akt, two kinases that play integral parts in cardioprotection and metabolic function. We hypothesized that chloroquine and resveratrol, both known ATM activators, would also activate AMPK and Akt.

Main methods

Phosphorylation of AMPK and Akt was assessed after C2C12 myotubes were exposed to chloroquine or resveratrol. Additional experiments were done in cells expressing shRNA against ATM or in the presence of the ATM inhibitor KU55933. The effects of chloroquine on intracellular calcium were assessed with the fluorescent probe Calcium Green-1 AM.

Key findings

0.5 mM chloroquine increased AMPK phosphorylation by nearly four-fold (P < 0.05), and 0.25 mM chloroquine roughly doubled Akt phosphorylation (P < 0.05). Chloroquine also increased autophosphorylation of ATM by ∼50% (P < 0.05). Resveratrol (0.15 mM) increased AMPK phosphorylation about three-fold (P < 0.05) but in contrast to chloroquine sharply decreased Akt phosphorylation. Chloroquine increased AMPK and Akt phosphorylation in myotubes expressing shRNA against ATM that reduced ATM protein levels by about 90%. Likewise, chloroquine-stimulated phosphorylation of AMPK and Akt and resveratrol-stimulated phosphorylation of AMPK were not altered by inhibition of ATM. Chloroquine decreased intracellular calcium by >50% concomitant with a decrease in glucose transport.

Significance

These ATM-independent effects of chloroquine on AMPK and Akt and the additional effect to decrease intracellular calcium are likely to partially underlie the positive metabolic effects of chloroquine that have been reported in the literature.

Impact of Hydroxychloroquine on Atherosclerosis and Vascular Stiffness in the Presence of Chronic Kidney Disease

Cardiovascular disease is the largest cause of morbidity and mortality among patients with chronic kidney disease (CKD) and end-stage kidney disease, with nearly half of all deaths attributed to cardiovascular disease. Hydroxychloroquine (HCQ), an anti-inflammatory drug, has been shown to have multiple pleiotropic actions relevant to atherosclerosis. We conducted a proof-of-efficacy study to evaluate the effects of hydroxychloroquine in an animal model of atherosclerosis in ApoE knockout mice with and without chronic kidney disease. Forty male, 6-week-old mice were divided into four groups in a 2 x 2 design: sham placebo group; sham treatment group; CKD placebo group; and CKD treatment group. CKD was induced by a two-step surgical procedure. All mice received a high-fat diet through the study duration and were sacrificed after 16 weeks of therapy. Mice were monitored with ante-mortem ultrasonic echography (AUE) for atherosclerosis and vascular stiffness and with post-mortem histology studies for atherosclerosis. Therapy with HCQ significantly reduced the severity of atherosclerosis in CKD mice and sham treated mice. HCQ reduced the area of aortic atherosclerosis on en face examination by approximately 60% in HCQ treated groups compared to the non-treated groups. Additionally, therapy with HCQ resulted in significant reduction in vascular endothelial dysfunction with improvement in vascular elasticity and flow patterns and better-preserved vascular wall thickness across multiple vascular beds. More importantly, we found that presence of CKD had no mitigating effect on HCQ's anti-atherosclerotic and vasculoprotective effects. These beneficial effects were not due to any significant effect of HCQ on inflammation, renal function, or lipid profile at the end of 16 weeks of therapy. This study, which demonstrates structural and functional protection against atherosclerosis by HCQ, provides a rationale to evaluate its use in CKD patients. Further studies are needed to define the exact mechanisms through which HCQ confers these benefits.

Toll-Like Receptor 9 Inactivation Alleviated Atherosclerotic Progression and Inhibited Macrophage Polarized to M1 Phenotype in ApoE-/- Mice

OBJECTIVE

Toll-like receptor 9 (TLR9) is involved in many inflammatory diseases, but its role in atherosclerosis remains controversial. This study aimed to investigate the role of TLR9 in atherosclerosis development and macrophage polarization.

METHODS

ApoE(-/-) mice were treated with vehicle or IRS869 for 12 weeks. Plaque vulnerability was assessed with immunohistochemical analysis, picro-sirius red, and oil red O staining. The expressions of M1- and M2-associated markers in plaques were detected by RT-PCR and immunofluorescence. The aorta TLR9 and its downstream molecules including myeloid differentiation protein 88 (MyD88), phosphorylated nuclear factor-kappa B (p-NF-κB), and interferon regulatory factor 7 (IRF7) were determined by western blot analysis. The frequency of M1 and M2 subtype in RAW264.7 cells treated with IRS869 and/or ODN1826 was evaluated with flow cytometry.

RESULTS

In ApoE(-/-) mice, functional inactivation of TLR9 pathway resulted in attenuated atherosclerosis development, as manifested by reduced plaque burden and by decreased plaque vulnerability. Mechanistically, TLR9 inhibition prevented the activation of MyD88/NF-κB pathway and shifted the balance of M1/M2 toward M2 macrophages that were involved.

CONCLUSIONS

Our data indicated that TLR9 inactivation ameliorated atherosclerosis via skewing macrophage plasticity to M2 phenotype in ApoE-deficient mice. These findings may provide a promising therapeutic strategy for atherosclerosis.

Can the DNA damage response be harnessed to modulate atherosclerotic plaque phenotype?

Gray et al 1 describe studies to examine smooth muscle cell (SMC)-selective effects of acceleration or inhibition of double-strand DNA break repair on atherosclerotic lesion phenotype in the ApoE-/- mouse model. Markers of the DNA damage response (DDR) and expression of DNA repair enzymes are both significantly elevated in human atherosclerotic plaques as compared with non-atherosclerotic mammary arteries,2 and are also increased in experimental models of atherosclerosis, a process that can be reversed by dietary lipid lowering.3 The report by Gray et al 1 provides important insights into the specific contribution of SMCs to plaque phenotype when the DDR is manipulated in vivo . While complementary analyses of double-strand DNA break repair in other major cell types within atherosclerotic lesions are needed, data from the studies by Gray et al 1 suggest the possibility of harnessing atheroprotective features of the ataxia telangiectasia mutated (ATM) kinase,4 , 5 a primary initiator of the DDR.

Atherosclerosis and tumor suppressor molecules (review)

Atherosclerosis, the major cause of heart attack and stroke, is a chronic inflammatory disease characterized by the formation of atherosclerotic plaque. Oxidized low-density lipoprotein through increased oxidative stress has been identified as one of the primary factors responsible for atherogenesis. Cell proliferation and death are key processes in the progression of atherosclerosis. The oxidative environment in areas of lipid accumulation is mainly created by the production of reactive oxygen species, which are assumed to mediate vascular tissue injury. Oxidative DNA damage and levels of DNA repair are reduced during dietary lipid lowering. The tumor suppressor molecules play a pivotal role in regulating cell proliferation, DNA repair and cell death, which are important processes in regulating the composition of atherosclerotic plaque. Accordingly, in this review, we discuss the fundamental role of tumor suppressor molecules in regulating atherogenesis. In particular, we discuss how tumor suppressor molecules are activated in the complex environment of atherosclerotic plaque, and regulate growth arrest, cell senescence and the apoptosis of vascular smooth muscle cells, which may protect against the progression of atherosclerosis. In addition, we discuss promising alternatives to the use of medications (such as statin) against atherosclerosis, namely diet, with the use of plant-derived supplements to modulate the expression and/or activity of tumor suppressor molecules. We also summarize the progress of research made on herbs with a focus on the modulatory roles of tumor suppressors, and on the molecular mechanisms underlying the prevention if atherosclerosis, supporting designs for further research in this field.

Association between a gene variant near ataxia telangiectasia mutated and coronary artery disease in men

OBJECTIVE

Type 2 diabetes is accompanied by increased mortality from coronary artery disease (CAD), but the mechanisms linking these conditions remain elusive. Hence, treatment of hyperglycaemia alone is not sufficient to avoid CAD in diabetes. Alternative views suggest that metabolic and vascular diseases share unifying cellular defects that could serve as targets for novel therapeutic strategies. Recently, a variant [single-nucleotide polymorphism (SNP); rs11212617] near the gene for ataxia telangiectasia mutated (ATM) has been associated with glycaemic response to metformin.

MATERIALS AND METHODS

We determined rs11212617 in 240 male patients who underwent elective coronary angiography.

RESULTS

While the variant was not associated with glucose concentrations, the A allele was significantly associated with the presence of CAD (chi-square, p = 0.003), as well as with logarithmically transformed quantitative CAD indices [severe score (SS): 0.5 (0.4-0.6) vs 0.3 (0.2-0.5); extent score (ES): 2.63 (2.4-2.9) vs 1.94 (1.4-2.4), both p < 0.05, respectively]. Multivariate analysis revealed an independent association between the A allele with ES (β = 0.17, p < 0.01).

CONCLUSION

Our data suggest that ATM-dependent signalling might play a role in the development of atherosclerotic vascular disease, but larger studies are necessary to substantiate such a hypothesis.

Molecular biology of atherosclerosis

At least 468 individual genes have been manipulated by molecular methods to study their effects on the initiation, promotion, and progression of atherosclerosis. Most clinicians and many investigators, even in related disciplines, find many of these genes and the related pathways entirely foreign. Medical schools generally do not attempt to incorporate the relevant molecular biology into their curriculum. A number of key signaling pathways are highly relevant to atherogenesis and are presented to provide a context for the gene manipulations summarized herein. The pathways include the following: the insulin receptor (and other receptor tyrosine kinases); Ras and MAPK activation; TNF-α and related family members leading to activation of NF-κB; effects of reactive oxygen species (ROS) on signaling; endothelial adaptations to flow including G protein-coupled receptor (GPCR) and integrin-related signaling; activation of endothelial and other cells by modified lipoproteins; purinergic signaling; control of leukocyte adhesion to endothelium, migration, and further activation; foam cell formation; and macrophage and vascular smooth muscle cell signaling related to proliferation, efferocytosis, and apoptosis. This review is intended primarily as an introduction to these key signaling pathways. They have become the focus of modern atherosclerosis research and will undoubtedly provide a rich resource for future innovation toward intervention and prevention of the number one cause of death in the modern world.

Multifaceted effects of hydroxychloroquine in human disease

OBJECTIVES

Hydroxychloroquine (HCQ) is a widely used medication for the treatment of rheumatoid arthritis and systemic lupus erythematosus. An increasing body of evidence supports actions of this drug that are not directly related to its immunosuppressive or anti-rheumatic properties. The objective of this systematic review is to characterize the spectrum of conditions that might be responsive to treatment with HCQ.

METHODS

PubMed was searched using the MeSH for HCQ with relevant subheadings and the limits of human topics and English language. Four-hundred and fifty-six abstracts from this search were examined individually to exclude those that were not focused on the objectives of this review. The resulting 76 articles were grouped according to topic areas and reviewed in detail.

RESULTS

HCQ has been reported to have therapeutic effects in a wide array of conditions, including diabetes mellitus, dyslipidemias, coagulopathies, infectious diseases and malignancies. Mechanisms of action responsible for these effects likely include altered signaling through cellular receptors, post-glycosylation modifications of infectious agents, changes in levels of inflammatory mediators and inhibition of autophagy. Many of the pathways are likely dependent on drug-induced changes in intra-endosomal acidity.

CONCLUSIONS

The use of, and interest in, HCQ has spread into many areas of medicine. Actions of this drug may be directly beneficial to patients with non-rheumatic conditions such as diabetes mellitus or viral infections. Further understanding of underlying mechanisms has potential to reveal modifiable pathogenic pathways that might elucidate approaches to the design of more effective therapeutics for many chronic diseases.

Effects of low-dose hydroxychloroquine on expression of phosphorylated Akt and p53 proteins and cardiomyocyte apoptosis in peri-infarct myocardium in rats

BACKGROUND

Low-dose hydroxychloroquine (HCQ) and ataxia-telangiectasia-mutated (ATM) protein kinase have recently been postulated to be beneficial for the prevention of the age-associated metabolic syndrome including hypertension, hypercholesterolemia and glucose intolerance; however, the effects of low-dose HCQ on the expression of ATM downstream phosphorylated Akt (protein kinase B) and p53 proteins and cardiomyocyte apoptosis in the peri-infarct myocardium remain unclear.

OBJECTIVE

To explore the effects of low-dose HCQ on the expression of phosphorylated Akt and p53 proteins and cardiomyocyte apoptosis in the peri-infarct myocardium in a rat model.

METHODS

Myocardial infarction (MI) was induced experimentally in a subset of rats, while others underwent sham operation (sham). Three days after operation, surviving Sprague-Dawley male rats were divided into MI+HCQ, MI, sham+HCQ and sham groups. MI+HCQ and sham + HCQ groups were treated with HCQ (3.4 mg/kg); and MI and sham groups were treated with phosphate buffered (ie, physiological) saline (10 mL/kg) by gavage every day for 12 weeks. The expression of phosphorylated Akt and p53 proteins and cardiomyocyte apoptosis in the peri-infarct myocardium was detected by Western blot and terminal deoxynucleotidyl transferase dUTP nick end labelling, respectively.

RESULTS

Twelve weeks after treatment, the expression of phosphorylated Akt protein was significantly increased (P<0.05). Expression of phosphorylated p53 protein was not significantly different (P>0.05) in the peri-infarct myocardium of the MI+HCQ group from that in the MI group. The cardiomyocyte apoptosis rate in the peri-infarct myocardium was significantly decreased in the MI+HCQ group compared with the MI group (P<0.05).

CONCLUSION

Low-dose HCQ can significantly increase the expression of phosphorylated Akt protein without significantly impacting expression of phosphorylated p53 protein in the peri-infarct myocardium. Accordingly, it can inhibit cardiomyocyte apoptosis in the peri-infarct myocardium.

Impaired insulin-stimulated glucose transport in ATM-deficient mouse skeletal muscle

There are reports that ataxia telangiectasia mutated (ATM) plays a role in insulin-stimulated Akt phosphorylation, although this is not the case in some cell types. Because Akt plays a key role in insulin signaling, which leads to glucose transport in skeletal muscle, the predominant tissue in insulin-stimulated glucose disposal, we examined whether insulin-stimulated Akt phosphorylation and (or) glucose transport would be decreased in skeletal muscle of mice lacking functional ATM, compared with muscle from wild-type mice. We found that in vitro insulin-stimulated Akt phosphorylation was normal in soleus muscle from mice with 1 nonfunctional allele of ATM (ATM+/-) and from mice with 2 nonfunctional alleles (ATM-/-). However, insulin did not stimulate glucose transport or the phosphorylation of AS160 in ATM-/- soleus. ATM protein level was markedly higher in wild-type extensor digitorum longus (EDL) than in wild-type soleus. In EDL from ATM-/- mice, insulin did not stimulate glucose transport. However, in contrast to findings for soleus, insulin-stimulated Akt phosphorylation was blunted in ATM-/- EDL, concomitant with a tendency for insulin-stimulated phosphatidylinositol 3-kinase activity to be decreased. Together, the findings suggest that ATM plays a role in insulin-stimulated glucose transport at the level of AS160 in muscle comprised of slow and fast oxidative-glycolytic fibers (soleus) and at the level of Akt in muscle containing fast glycolytic fibers (EDL).

Aging and atherosclerosis: mechanisms, functional consequences, and potential therapeutics for cellular senescence

Atherosclerosis is classed as a disease of aging, such that increasing age is an independent risk factor for the development of atherosclerosis. Atherosclerosis is also associated with premature biological aging, as atherosclerotic plaques show evidence of cellular senescence characterized by reduced cell proliferation, irreversible growth arrest and apoptosis, elevated DNA damage, epigenetic modifications, and telomere shortening and dysfunction. Not only is cellular senescence associated with atherosclerosis, there is growing evidence that cellular senescence promotes atherosclerosis. This review examines the pathology of normal vascular aging, the evidence for cellular senescence in atherosclerosis, the mechanisms underlying cellular senescence including reactive oxygen species, replication exhaustion and DNA damage, the functional consequences of vascular cell senescence, and the possibility that preventing accelerated cellular senescence is a therapeutic target in atherosclerosis.

The role of antimalarial agents in the treatment of SLE and lupus nephritis

Systemic lupus erythematosus (SLE) is a multisystem autoimmune disease that affects various organs. Lupus nephritis is one of the most common, and most important, serious manifestations of SLE. Antimalarial agents are part of the immunomodulatory regimen used to treat patients with SLE; however, their role in the treatment of patients with lupus nephritis in particular is less well recognized, especially by nephrologists. Not all antimalarial agents have been used in the treatment of lupus; this Review will focus on studies using chloroquine and hydroxychloroquine. In addition, this Review will briefly describe the history of antimalarial drug use in patients with SLE, the theorized mechanisms of action of the agents chloroquine and hydroxychloroquine, their efficacy in patients with SLE and those with lupus nephritis, their use in pregnancy, and potential adverse effects. The Review will also cover the latest recommendations regarding monitoring for hydroxychloroquine-associated or chloroquine-associated retinopathy. Overall, antimalarial drugs have numerous beneficial effects in patients with SLE and lupus nephritis, and have a good safety profile.