A randomized trial of aspirin at clinically relevant doses and nitric oxide formation in humans

Drug-Drug Interaction between Antiplatelet Therapy and Lipid-Lowering Agents (Statins and PCSK9 Inhibitors)

Lipid-lowering agents and antiplatelet drugs are guideline-recommended standard treatment for secondary prevention of acute thrombotic events in patients with increased cardiovascular risk. Aspirin is the most frequently used antiplatelet drug, either alone or in combination with other antiplatelet agents (P2Y₁₂ inhibitors), while statins are first-line treatment of hypercholesterolemia. The well-established mode of action of aspirin is inhibition of platelet-dependent thromboxane formation. In addition, aspirin also improves endothelial oxygen defense via enhanced NO formation and inhibits thrombin formation. Low-dose aspirin exerts in addition anti-inflammatory effects, mainly via inhibition of platelet-initiated activation of white cells.Statins inhibit platelet function via reduction of circulating low-density lipoprotein-cholesterol (LDL-C) levels and a more direct inhibition of platelet function. This comprises inhibition of thromboxane formation via inhibition of platelet phospholipase A₂ and inhibition of (ox)LDL-C-mediated increases in platelet reactivity via the (ox)LDL-C receptor (CD36). Furthermore, statins upregulate endothelial NO-synthase and improve endothelial oxygen defense by inhibition of NADPH-oxidase. PCSK9 antibodies target a serine protease (PCSK9), which promotes the degradation of the LDL-C receptor impacting on LDL-C plasma levels and (ox)LDL-C-receptor-mediated signaling in platelets similar to but more potent than statins.These functionally synergistic actions are the basis for numerous interactions between antiplatelet and these lipid-lowering drugs, which may, in summary, reduce the incidence of atherothrombotic vascular events.

The Role of Endothelial Cells in the Onset, Development and Modulation of Vein Graft Disease

Endothelial cells comprise the intimal layer of the vasculature, playing a crucial role in facilitating and regulating aspects such nutrient transport, vascular homeostasis, and inflammatory response. Given the importance of these cells in maintaining a healthy haemodynamic environment, dysfunction of the endothelium is central to a host of vascular diseases and is a key predictor of cardiovascular risk. Of note, endothelial dysfunction is believed to be a key driver for vein graft disease-a pathology in which vein grafts utilised in coronary artery bypass graft surgery develop intimal hyperplasia and accelerated atherosclerosis, resulting in poor long-term patency rates. Activation and denudation of the endothelium following surgical trauma and implantation of the graft encourage a host of immune, inflammatory, and cellular differentiation responses that risk driving the graft to failure. This review aims to provide an overview of the current working knowledge regarding the role of endothelial cells in the onset, development, and modulation of vein graft disease, as well as addressing current surgical and medical management approaches which aim to beneficially modulate endothelial function and improve patient outcomes.

Endothelium as a Therapeutic Target in Diabetes Mellitus: From Basic Mechanisms to Clinical Practice

Endothelium plays an essential role in human homeostasis by regulating arterial blood pressure, distributing nutrients and hormones as well as providing a smooth surface that modulates coagulation, fibrinolysis and inflammation. Endothelial dysfunction is present in Diabetes Mellitus (DM) and contributes to the development and progression of macrovascular disease, while it is also associated with most of the microvascular complications such as diabetic retinopathy, nephropathy and neuropathy. Hyperglycemia, insulin resistance, hyperinsulinemia and dyslipidemia are the main factors involved in the pathogenesis of endothelial dysfunction. Regarding antidiabetic medication, metformin, gliclazide, pioglitazone, exenatide and dapagliflozin exert a beneficial effect on Endothelial Function (EF); glimepiride and glibenclamide, dipeptidyl peptidase-4 inhibitors and liraglutide have a neutral effect, while studies examining the effect of insulin analogues, empagliflozin and canagliflozin on EF are limited. In terms of lipid-lowering medication, statins improve EF in subjects with DM, while data from short-term trials suggest that fenofibrate improves EF; ezetimibe also improves EF but further studies are required in people with DM. The effect of acetylsalicylic acid on EF is dose-dependent and lower doses improve EF while higher ones do not. Clopidogrel improves EF, but more studies in subjects with DM are required. Furthermore, angiotensin- converting-enzyme inhibitors /angiotensin II receptor blockers improve EF. Phosphodiesterase type 5 inhibitors improve EF locally in the corpus cavernosum. Finally, cilostazol exerts favorable effect on EF, nevertheless, more data in people with DM are required.

Can Endothelial Glycocalyx Be a Major Morphological Substrate in Pre-Eclampsia?

Today pre-eclampsia (PE) is considered as a disease of various theories; still all of them agree that endothelial dysfunction is the leading pathogenic factor. Endothelial dysfunction is a sequence of permanent immune activation, resulting in the change of both the phenotype and the functions of an endothelial cell and of the extracellular layer associated with the cell membrane—endothelial glycocalyx (eGC). Numerous studies demonstrate that eGC mediates and regulates the key functions of endothelial cells including regulation of vascular tone and thromboresistance; and these functions are disrupted during PE. Taking into account that eGC and its components undergo alterations under pathological conditions leading to endothelial activation, it is supposed that eGC plays a certain role in pathogenesis of PE. Envisaging the eGC damage as a key factor of PE, might be a new approach to prevention, treatment, and rehabilitation of patients with PE. This approach could include the development of drugs protecting eGC and promoting regeneration of this structure. Since the issue of PE is far from being solved, any effort in this direction might be valuable.

Low-Dose Aspirin Treatment Attenuates Male Rat Salt-Sensitive Hypertension via Platelet Cyclooxygenase 1 and Complement Cascade Pathway

Background The role of platelets in the development of vascular inflammation and endothelial dysfunction in the pathogenesis of hypertension is well established at this time. Aspirin is known to relieve pain, decrease fever, reduce inflammation, impair platelet aggregation, and prevent clotting, yet its effect in the context of salt-sensitive hypertension remains unclear. The present study investigated the importance of aspirin in inhibiting the abnormal activation of platelets and promoting the normal function of the vascular endothelium in a rat model of salt-sensitive hypertension. Method and Results Dahl salt-sensitive rats and salt-resistant rats were fed a normal-salt diet (4% NaCl), a high-salt diet (8% NaCl), or a high-salt diet with aspirin gavage (10 mg/kg per day) for 8 weeks. Blood pressure, platelet activation, vascular function, inflammatory response, and potential mechanism were measured. Low-dose aspirin (10 mg/kg per day) decreased the high-salt diet-induced elevation of blood pressure, platelet activation, leukocyte infiltration, and leukocyte-platelet aggregation (CD45+CD61+), as well as vascular endothelial and renal damage. These effects were related to the ability of aspirin to prevent the adhesion of leukocytes to endothelial cells via inhibition of the platelet cyclooxygenase 1 but not the cyclooxygenase 2 pathway. Aspirin also reversed the high-salt diet-induced abnormal activation of complement and coagulation cascades in platelets. Conclusions These results highlight a new property of aspirin in ameliorating vascular endothelial dysfunction induced by platelet activation, which may be beneficial in the treatment of salt-sensitive hypertension.

Effects of aspirin on risks of vascular events and cancer according to bodyweight and dose: analysis of individual patient data from randomised trials

BACKGROUND

A one-dose-fits-all approach to use of aspirin has yielded only modest benefits in long-term prevention of cardiovascular events, possibly due to underdosing in patients of large body size and excess dosing in patients of small body size, which might also affect other outcomes.

METHODS

Using individual patient data, we analysed the modifying effects of bodyweight (10 kg bands) and height (10 cm bands) on the effects of low doses (≤100 mg) and higher doses (300-325 mg or ≥500 mg) of aspirin in randomised trials of aspirin in primary prevention of cardiovascular events. We stratified the findings by age, sex, and vascular risk factors, and validated them in trials of aspirin in secondary prevention of stroke. Additionally, we assessed whether any weight or height dependence was evident for the effect of aspirin on 20-year risk of colorectal cancer or any in-trial cancer.

RESULTS

Among ten eligible trials of aspirin in primary prevention (including 117 279 participants), bodyweight varied four-fold and trial median weight ranged from 60·0 kg to 81·2 kg (p<0·0001). The ability of 75-100 mg aspirin to reduce cardiovascular events decreased with increasing weight (pinteraction=0·0072), with benefit seen in people weighing 50-69 kg (hazard ratio [HR] 0·75 [95% CI 0·65-0·85]) but not in those weighing 70 kg or more (0·95 [0·86-1·04]; 1·09 [0·93-1·29] for vascular death). Furthermore, the case fatality of a first cardiovascular event was increased by low-dose aspirin in people weighing 70 kg or more (odds ratio 1·33 [95% CI 1·08-1·64], p=0·0082). Higher doses of aspirin (≥325 mg) had the opposite interaction with bodyweight (difference pinteraction=0·0013), reducing cardiovascular events only at higher weight (pinteraction=0·017). Findings were similar in men and women, in people with diabetes, in trials of aspirin in secondary prevention, and in relation to height (pinteraction=0·0025 for cardiovascular events). Aspirin-mediated reductions in long-term risk of colorectal cancer were also weight dependent (pinteraction=0·038). Stratification by body size also revealed harms due to excess dosing: risk of sudden death was increased by aspirin in people at low weight for dose (pinteraction=0·0018) and risk of all-cause death was increased in people weighing less than 50 kg who were receiving 75-100 mg aspirin (HR 1·52 [95% CI 1·04-2·21], p=0·031). In participants aged 70 years or older, the 3-year risk of cancer was also increased by aspirin (1·20 [1·03-1·47], p=0·02), particularly in those weighing less than 70 kg (1·31 [1·07-1·61], p=0·009) and consequently in women (1·44 [1·11-1·87], p=0·0069).

INTERPRETATION

Low doses of aspirin (75-100 mg) were only effective in preventing vascular events in patients weighing less than 70 kg, and had no benefit in the 80% of men and nearly 50% of all women weighing 70 kg or more. By contrast, higher doses of aspirin were only effective in patients weighing 70 kg or more. Given that aspirin's effects on other outcomes, including cancer, also showed interactions with body size, a one-dose-fits-all approach to aspirin is unlikely to be optimal, and a more tailored strategy is required.

FUNDING

Wellcome Trust and National Institute for Health Research Oxford Biomedical Research Centre.

Antiinflammatory effects of aspirin in ACS: relevant to its cardio coronary actions?

Vascular injury in acute coronary syndromes (ACS) involves a complex cross-talk between inflammatory mediators, platelets and thrombosis, where the interaction between platelets and coagulation factors (e. g. thrombin) is a central link between thrombosis and inflammation. In ACS, aspirin at antiplatelet doses exhibits anti-inflammatory effects as seen from the decrease in inflammation markers such as CRP, M-CSF, MCP-1 and others. These actions probably occur subsequent to inhibition of platelet COX-1-dependent thromboxane formation and its action as a multipotent autocrine and paracrine agent. This likely involves inhibition of thrombin formation as well as inhibition of secondary pro-inflammatory mediators, such as sphingosine-1-phosphate. Experimental and limited clinical data additionally suggest antiinflammatory effects of aspirin independent of its antiplatelet action. For example, aspirin at antiplatelet doses might acetylate COX-2 in vascular cells, directing the activity of the enzyme into a 15-lipoxygenase which by transcellular metabolism results in the formation of 15-epi-lipoxin (‘aspirin-triggered lipoxin’), an antiinflammatory mediator. Furthermore, aspirin stimulates eNOS via lysine-acetylation, eventually resulting in induction of heme oxygenase (HO-1), which improves the antioxidative potential of vascular cells. All of these effects have been seen at antiplatelet doses of 100–300 mg/day, equivalent to peak plasma levels of 10–30 μM. Many more potentially antiinflammatory mechanisms of aspirin have been described, mostly salicy-late-related, at low to medium millimolar concentrations and, therefore, are of minor clinical interest. Altogether, there is a wealth of data supporting antiiflammatory effects of aspirin in ACS, but studies generating direct evidence for antiinflammatory effects in ACS remain to be done.

Quantifying the Effects of Prior Acetyl-Salicylic Acid on Sepsis-Related Deaths: An Individual Patient Data Meta-Analysis Using Propensity Matching

OBJECTIVE

The primary objective was to conduct a meta-analysis on published observational cohort data describing the association between acetyl-salicylic acid (aspirin) use prior to the onset of sepsis and mortality in hospitalized patients.

STUDY SELECTION

Studies that reported mortality in patients on aspirin with sepsis with a comparison group of patients with sepsis not on prior aspirin therapy were included.

DATA SOURCES

Fifteen studies described hospital-based cohorts (n = 17,065), whereas one was a large insurance-based database (n = 683,421). Individual-level patient data were incorporated from all selected studies.

DATA EXTRACTION

Propensity analyses with 1:1 propensity score matching at the study level were performed, using the most consistently available covariates judged to be associated with aspirin. Meta-analyses were performed to estimate the pooled average treatment effect of aspirin on sepsis-related mortality.

DATA SYNTHESIS

Use of aspirin was associated with a 7% (95% CI, 2-12%; p = 0.005) reduction in the risk of death as shown by meta-analysis with considerable statistical heterogeneity (I = 61.6%).

CONCLUSIONS

These results are consistent with effects ranging from a 2% to 12% reduction in mortality risk in patients taking aspirin prior to sepsis onset. This association anticipates results of definitive studies of the use of low-dose aspirin as a strategy for reduction of deaths in patients with sepsis.

Influence of Low-Dose Aspirin on Cerebral Amyloid Angiopathy in Mice

Accumulation of amyloid-β peptide (Aβ) in the brain is one of the most important features of Alzheimer's dementia (AD). Cerebral amyloid angiopathy (CAA) is characterized by Aβ accumulation in the walls of cerebral arteries and capillaries, and is present in over 90% of patients with AD. Several novel agents for AD/CAA developed around the amyloid hypothesis have shown positive signs in animal studies but have failed in clinical trials due to adverse events and/or lack of efficiency. As CAA is presumably caused by a failure in Aβ clearance, drugs that promote Aβ clearance may hold promise in the treatment of CAA and possibly AD. With this in mind, cilostazol, an anti-platelet drug with vasodilating action, has been found to promote Aβ clearance along perivascular drainage pathway, reduce Aβ accumulation in the brain, and restore memory impairment in Tg-SwDI mice, an animal model of CAA. We therefore tested whether the most common anti-platelet agent, aspirin, also reduced Aβ and rescued cognitive impairment in Tg-SwDI mice, and also whether aspirin affected hemorrhagic complications that can occur in Tg-SwDI mice. Mice aged 4 months were assigned into vehicle-treated and low-dose aspirin-treated groups. Low-dose aspirin for 8 months did not increase hemorrhagic lesions, nor increase resting cerebral blood flow or cerebral vascular reserve in response to hypercapnia or acetylcholine. Subsequently, aspirin did not restore cognitive dysfunction. These results suggest that low-dose aspirin does not have a direct influence on cerebrovascular Aβ metabolism nor aggravate hemorrhagic complications in CAA.

AspiriN To Inhibit SEPSIS (ANTISEPSIS) randomised controlled trial protocol

INTRODUCTION

Sepsis is a leading global cause of morbidity and mortality, and is more common at the extremes of age. Moreover, the cost of in-hospital care for elderly patients with sepsis is significant. There are indications from experimental and observational studies that aspirin may reduce inflammation associated with infection. This paper describes the rationale and design of the AspiriN To Inhibit SEPSIS (ANTISEPSIS) trial, a substudy of ASPirin in Reducing Events in the Elderly (ASPREE). ANTISEPSIS primarily aims to determine whether low-dose aspirin reduces sepsis-related deaths in older people. Additionally, it will assess whether low-dose aspirin reduces sepsis-related hospitalisations and sepsis-related Intensive Care Unit (ICU) admissions.

METHODS AND ANALYSIS

ASPREE is a double-blinded, randomised, placebo-controlled primary prevention trial that will determine whether daily low-dose aspirin extends disability-free longevity in 19 000 healthy older people recruited in Australia and the USA. The ANTISEPSIS substudy involves additional ASPREE trial data collection to assess the impact of daily low-dose aspirin on sepsis-related events in the 16 703 ASPREE participants aged 70 years and over, recruited in Australia. The intervention is a daily 100 mg dose of enteric-coated aspirin versus matching placebo, with 1:1 randomisation. The primary outcome for the ANTISEPSIS substudy is the incidence of sepsis-related death in eligible patients. The incidence of sepsis-related hospital and ICU admissions are secondary outcomes. ANTISEPSIS is to be conducted between 2012 and 2018.

DISCUSSION

This substudy will determine whether aspirin, an inexpensive and accessible therapy, safely reduces sepsis-related deaths and hospitalisations in older Australians. If shown to be the case, this would have profound effects on the health of older Australians.

TRIAL REGISTRATION NUMBER

Pre-results, ACTRN12613000349741.

Effects of Aspirin on Endothelial Function and Hypertension

PURPOSE OF REVIEW

Endothelial dysfunction is intimately related to the development of various cardiovascular diseases, including hypertension, and is often used as a target for pharmacological treatment. The scope of this review is to assess effects of aspirin on endothelial function and their clinical implication in arterial hypertension.

RECENT FINDINGS

Emerging data indicate the role of platelets in the development of vascular inflammation due to the release of proinflammatory mediators, for example, triggered largely by thromboxane. Vascular inflammation further promotes oxidative stress, diminished synthesis of vasodilators, proaggregatory and procoagulant state. These changes translate into vasoconstriction, impaired circulation and thrombotic complications. Aspirin inhibits thromboxane synthesis, abolishes platelets activation and acetylates enzymes switching them to the synthesis of anti-inflammatory substances. Aspirin pleiotropic effects have not been fully elucidated yet. In secondary prevention studies, the decrease in cardiovascular events with aspirin outweighs bleeding risks, but this is not the case in primary prevention settings. Ongoing trials will provide more evidence on whether to expand the use of aspirin or stay within current recommendations.

Diabetic macular edema, retinopathy and age-related macular degeneration as inflammatory conditions

Diabetic macular edema (DME) and diabetic retinopathy (DR) are complications affecting about 25% of all patients with long-standing type 1 and type 2 diabetes mellitus and are a major cause of significant decrease in vision and quality of life. Age-related macular degeneration (AMD) is not uncommon, and diabetes mellitus affects the incidence and progression of AMD through altering hemodynamics, increasing oxidative stress, accumulating advanced glycation end products, etc. Recent studies suggest that DME, DR and AMD are inflammatory conditions characterized by a breakdown of the blood-retinal barrier, inflammatory processes and an increase in vascular permeability. Key factors that seem to have a dominant role in DME, DR and AMD are angiotensin II, prostaglandins and the vascular endothelial growth factor and a deficiency of anti-inflammatory bioactive lipids. The imbalance between pro- and anti-inflammatory eicosanoids and enhanced production of pro-angiogenic factors may initiate the onset and progression of DME, DR and AMD. This implies that bioactive lipids that possess anti-inflammatory actions and suppress the production of angiogenic factors could be employed in the prevention and management of DME, DR and AMD.

Aspirin Reduces Plasma Concentrations of the Oncometabolite 2-Hydroxyglutarate: Results of a Randomized, Double-Blind, Crossover Trial

BACKGROUND

Aspirin use is an effective strategy for the chemoprevention of colorectal cancer, even at low doses. However, in order to implement aspirin interventions, risk-benefit balances and biologic mechanisms need to be better defined; to further this aim, we used a metabolomics approach.

METHODS

We metabolically profiled 40 healthy, nonsmoking men and women ages 20 to 45 years enrolled in a randomized, double-blind, crossover trial of 325 mg aspirin/day over a period of 60 days. Gas and liquid chromatography-mass spectrometry were used to comprehensively profile participants' plasma samples after aspirin and placebo interventions.

RESULTS

A total of 363 metabolites, covering most human biochemical pathways, were measured. Compared with placebo-treated participants, plasma concentrations of the oncometabolite 2-hydroxyglutarate (R+S) decreased after aspirin treatment in both men and women (P = 0.005). This signal proved robust during 20-fold random splitting of the data using 80% of the samples in each split. We subsequently performed functional follow-up studies using targeted, enantiospecific detection in human colorectal cancer cell lines and observed an aspirin-induced reduction of (R)-2-hydroxyglutarate. We further showed that salicylate, the primary aspirin metabolite, inhibits the hydroxyacid-oxoacid transhydrogenase mediated production of (R)-2-hydroxyglutarate, thereby providing mechanistic evidence for the clinically observed effects of aspirin on total-2-hydroxyglutarate.

CONCLUSIONS

Using a metabolomics approach with functional follow-up, we propose that a decrease in the oncometabolite (R)-2-hydroxyglutarate may identify an additional mechanism for aspirin or its metabolites in cancer prevention.

IMPACT

Reduction of the oncometabolite (R)-2-hydroxyglutarate identifies a novel, non-COX-inhibition-mediated mechanism of aspirin.

Aspirin in the 21st century-common mechanisms of disease and their modulation by aspirin: a report from the 2015 scientific conference of the international aspirin foundation, 28 August, London, UK

Professor Peter Rothwell of Oxford University chaired the annual Scientific Conference of the International Aspirin Foundation in London on 28 August 2015. It took the form of four sessions. Aspirin has more than one action in its effects on disease. Its acetylation of cyclooxygenase 2 (COX-2) in platelets leads to the blockade of pro-inflammatory chemicals and generation of anti-inflammatory mediators and increase in nitrous oxide (NO) production, which helps to preserve arterial endothelium. But platelets are not its only target. There is now evidence that aspirin has a direct antitumour effect on intestinal mucosal cells that block their potential transformation into cancer cells. Randomised placebo-controlled trials (RCTs) in people with histories of colorectal neoplasia have shown that aspirin reduces the risk of recurrent adenomas and reduces long-term cancer incidence in patients with Lynch syndrome. Among women given aspirin for cardiovascular disease, there were fewer cancers than in those given placebo. Epidemiological evidence has suggested that aspirin treatment after cancer is diagnosed reduces the incidence of metastases and prolongs survival, and long-term studies of anticancer treatment with aspirin are under way to confirm this. Apart from cancer studies, aspirin use is now firmly established as treatment for antiphospholipid syndrome (Hughes syndrome) and is being used to prevent and treat the heightened risk of cardiovascular disease in diabetes mellitus and in patients with HIV.

Preventing cardiovascular disease in patients with diabetes: use of aspirin for primary prevention

Diabetics are at high risk for atherosclerotic cardiovascular disease (ASCVD) and are considered a coronary heart disease risk equivalent. The utility of aspirin in primary prevention of ASCVD in diabetic patients has been widely studied and is still debated. Overall, the current evidence suggests a modest benefit for reduction in ASCVD events with the greatest benefit among those with higher baseline risk, but at the cost of increased risk of gastrointestinal bleeding. Diabetic patients at higher risk (with 10-year ASCVD risk >10 %) are generally recommended for aspirin therapy if bleeding risk is felt to be low. A patient-provider discussion is recommended before prescribing aspirin therapy. Novel markers such as coronary artery calcium scores and high-sensitivity C-reactive protein may help refine ASCVD risk prediction and guide utility for aspirin therapy. This article will review the literature for the most up-to-date studies evaluating aspirin therapy for primary prevention of ASCVD in patients with diabetes.

Effects of aspirin & simvastatin and aspirin, simvastatin, & lipoic acid on heme oxygenase-1 in healthy human subjects

BACKGROUND

Heme oxygenase 1 (HO-1) degrades heme and protects against oxidative stress. In vitro and animal models suggest that HO-1 is beneficial in several diseases (e.g., postoperative ileus, gastroparesis, acute pancreatitis, and colitis). However, the only drugs (i.e., hemin and heme arginate) which pharmacologically upregulate HO-1 in humans are expensive and can only be administered intravenously. Our aims were to compare the effects of placebo, aspirin, and simvastatin alone, and with α-lipoic acid, on HO-1 protein concentration and activity in humans.

METHODS

This randomized, double-blind, placebo-controlled study compared the effects of three oral regimens administered for 7 days, i.e., placebo; aspirin (325 mg twice daily) and simvastatin (40 mg twice daily); aspirin, simvastatin, and the sodium salt of R- α-lipoic acid (NaRLA, 600 mg three times daily) on markers of HO-1 activation (i.e., plasma HO-1 protein concentration and venous monocyte HO-1 protein activity) in 18 healthy subjects (14 females). Markers of HO-1 activation were evaluated at baseline, days 2, and 7.

KEY RESULTS

Baseline HO-1 protein concentrations and activity were similar among the three groups. Compared to placebo, aspirin and simvastatin combined, or together with NaRLA did not affect HO-1 protein concentration or activity at 2 or 7 days. HO-1 protein concentrations and activity were correlated on day 7 (r = 0.75, p = 0.0004) but not at baseline and on day 2.

CONCLUSIONS & INFERENCES

At therapeutic doses, aspirin, simvastatin, and α-lipoic acid do not increase plasma HO-1 protein concentration or venous monocyte HO-1 activity in healthy humans.

Aspirin in the treatment and prevention of cardiovascular disease: past and current perspectives and future directions

In secondary prevention among a wide range of patients who have survived a prior occlusive vascular event, as well as during acute myocardial infarction and acute occlusive stroke, aspirin produces statistically significant and clinically important reductions in the risk of subsequent myocardial infarction, stroke, and vascular death. In primary prevention, aspirin reduces risk of a first myocardial infarction, but the data on stroke and vascular deaths remain inconclusive. In addition, the average absolute risk of subjects randomized in the primary prevention trials was so low that it is not possible to get reliable estimates of the benefit-to-risk ratio in primary prevention in subjects at moderate risk. Until the results of ongoing trials are available, nobody would disagree that a nonfatal myocardial infarction or stroke is more likely to be disabling than a nonfatal bleed. Thus, in primary prevention at present, the appropriate and judicious use of aspirin by clinicians based on individual clinical judgments that weigh their absolute benefits against the absolute risks of the drug, will avoid premature morbidity and possibly, mortality.

Aspirin increases nitric oxide formation in chronic stable coronary disease

INTRODUCTION

There are no published randomized data on secondary prevention in humans about whether aspirin affects nitric oxide (NO) formation. In patients with chronic stable coronary disease, we tested whether aspirin at clinically relevant doses increases NO formation.

MATERIALS AND METHODS

In a randomized, double-blind trial, 37 patients from 2 cardiology office practices were assigned to daily doses of 81, 162.5, 325, 650, or 1300 aspirin for 12 weeks. Primary prespecified outcome measures were changes in heme oxygenase (HO-1), a downstream target of NO formation, and asymmetrical dimethyl arginine (ADMA), a competitive inhibitor of NO synthase.

RESULTS

There were no significant differences for HO-1 or ADMA between any of the clinically relevant doses of aspirin tested, so all were combined. For HO-1, there was a significant increase (10.29 ± 2.44, P < .001) from baseline (15.37 ± 1.85) to week 12 (25.66 ± 1.57). The mean ratio (MR) of week 12 to baseline for HO-1 was significantly higher than 1.0 (1.67, confidence interval [CI] from 1.60 to 1.74, P < .001). For ADMA, there was a significant decrease (-0.24 ± 0.11, P < .001) from baseline (0.78 ± 0.08) to week 12 (0.54 ± 0.07). The MR of week 12 to baseline for ADMA was significantly lower than 1.0 (0.69, CI from 0.66 to 0.73, P < .001).

CONCLUSIONS

In patients with chronic stable coronary disease, all clinically relevant daily doses of aspirin tested, from 81 to 1300 mg, produce similar and statistically significant increases in HO-1 and decreases in ADMA. These are the first randomized data on secondary prevention patients. These data support the hypothesis that aspirin has additional beneficial effects mediated through NO formation. Further research, including direct randomized comparisons on atherosclerosis using noninvasive techniques as well as on occlusive vascular disease events, is necessary.

HIV replication, inflammation, and the effect of starting antiretroviral therapy on plasma asymmetric dimethylarginine, a novel marker of endothelial dysfunction

BACKGROUND

HIV infection is associated with premature development of cardiovascular disease. Understanding the effects of HIV replication on endothelial dysfunction and platelet activation may identify treatment targets to reduce cardiovascular disease risk.

METHODS

A subgroup of HIV-infected participants in the Strategies for Management of Antiretroviral Therapy study off antiretroviral therapy (ART) at entry enabled a randomized comparison of immediate versus deferred ART initiation of changes in asymmetric dimethylarginine (ADMA), soluble CD40 ligand (sCD40L), and P-selectin levels.

RESULTS

At study entry, median (interquartile range) levels of ADMA, sCD40L, and P-selectin were 0.57 (0.49-0.66) μg/mL, 251 (135-696) μmol/L, and 34 (28-44) pg/mL. Compared to those randomized to deferral of ART (n = 114), participants randomized to immediate ART (n = 134) had 10.3% lower ADMA levels (P = 0.003) at 12 months; treatment differences in sCD40L (95% confidence interval: -17% to 44%; P = 0.53) and P-selectin (95% confidence interval: -10% to 10%; P = 0.95) were not significant. The difference in ADMA for those assigned immediate ART compared with those assigned ART deferral was greater among younger patients and those with higher levels of high-sensitivity C-reactive protein and D-dimer (P ≤ 0.05 for interaction for both) but not HIV RNA level at baseline (P = 0.51).

DISCUSSION

ART initiation leads to declines in ADMA levels, a marker of nitric oxide-mediated endothelial dysfunction. Improvement in ADMA levels was related to the degree of inflammation and coagulation, suggesting that upregulation of these pathways contributes to premature vascular disease among individuals with HIV infection. Whether declines in ADMA levels impact risk of disease requires further research.

Inhibition of Murine Systemic Leishmaniasis by Acetyl Salicylic Acid via Nitric Oxide Immunomodulation

BACKGROUND

The purpose of this study was to evaluate antileishmanial effects of ASA via NO pathway in Leishmania major infected Balb/c mice. Moreover, toxicity and pathological consequences of ASA administration were investigated.

METHODS

Balb/c mice were infected with L. major and ASA was inoculated orally after lesion appearance for its ability to modulate NO and to modify Leishmania infection in host, in order to evaluate the effects of NO production on size and lesion macroscopy, delay of lesion formation and proliferation of amastigotes inside macrophages. Liver, spleen, and lymph nodes were also studied as target organs to detect amastigotes. In addition, plasma was investigated for NO induction using Griess microassay.

RESULTS

ASA increased NO production in plasma of both naïve and Leishmania test groups at the ultimate of the experimental period. A decline was observed in proliferation of amastigotes inside macrophages of test group when compared with control one. ASA reduced lesion size, inhibited Leishmania visceralisation in spleen, lymph node, and decreased hepato/splenomegaly in ASA treated animals.

CONCLUSIONS

Some antileishmanial effects of ASA by NO-modulation were indicated during systemic leishmaniasis in mice. Despite slight effects on lesion size, ASA decreased parasite visceralization in target organs and declined their proliferation inside macrophages. Therefore, ASA may be indicated to inhibit systemic leishmaniasis via NO pathway in mice model.