Omega-3 fatty acids and cardiovascular prevention: is the jury still out?

The cardiovascular benefits of omega-3 polyunsaturated fatty acids (O3FA) remain a point of confusion in clinical medicine. Recently two large, randomised trials were published with discordant findings regarding the overall benefits of omega-3 supplementation, resulting in unnecessary confusion and therapeutic nihilism. Epidemiological studies clearly show high intake of fish and measured O3FA (mainly eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)) in tissues are inversely associated with cardiovascular events and total mortality. These fatty acids are 'essential' and depend almost entirely on intake with very little production from within the body. The efficacy of supplementation depends on background tissue levels, in contradistinction to drug therapy. Insufficient dosing of omega-3 supplementation using less than 1 g/day and lack of titration to target by failing to measure O3FA levels in the blood may explain these conflicting trial outcomes. We review the current evidence regarding O3FA supplementation and cardiovascular outcomes, describe possible reasons for the discrepant results in the literature including recent controversial data around the mineral oil comparator used in REDUCE-IT and discuss the potential use of the omega-3 index to guide management and optimise supplementation in those at greatest risk.

A Clinical Guide for Assessment and Prescription of Exercise and Physical Activity in Cardiac Rehabilitation. A CSANZ Position Statement.

Patients with cardiovascular disease benefit from cardiac rehabilitation, which includes structured exercise and physical activity as core components. This position statement provides pragmatic, evidence-based guidance for the assessment and prescription of exercise and physical activity for cardiac rehabilitation clinicians, recognising the latest international guidelines, scientific evidence and the increasing use of technology and virtual delivery methods. The patient-centred assessment and prescription of aerobic exercise, resistance exercise and physical activity have been addressed, including progression and safety considerations.

Australian Atherosclerosis Society Position Statement on Lipoprotein(a): Clinical and Implementation Recommendations.

This position statement provides guidance to cardiologists and related specialists on the management of adult patients with elevated lipoprotein(a) [Lp(a)]. Elevated Lp(a) is an independent and causal risk factor for atherosclerotic cardiovascular disease (ASCVD) and calcific aortic valve disease (CAVD). While circulating Lp(a) levels are largely determined by ancestry, they are also influenced by ethnicity, hormones, renal function, and acute inflammatory events, such that measurement should be done after accounting for these factors. Further, circulating Lp(a) concentrations should be estimated using an apo(a)-isoform independent assay that employs appropriate calibrators and reports the results in molar units (nmol/L). Selective screening strategies of high-risk patients are recommended, but universal screening of the population is currently not advised. Testing for elevated Lp(a) is recommended in all patients with premature ASCVD and those considered to be at intermediate-to-high risk of ASCVD. Elevated Lp(a) should be employed to assess and stratify risk and to enable a decision on initiation or intensification of preventative treatments, such as cholesterol lowering therapy. In adult patients with elevated Lp(a) at intermediate-to-high risk of ASCVD, absolute risk should be reduced by addressing all modifiable behavioural, lifestyle, psychosocial and clinical risk factors, including maximising cholesterol-lowering with statin and ezetimibe and, where appropriate, PCSK9 inhibitors. Apheresis should be considered in patients with progressive ASCVD. New ribonucleic acid (RNA)-based therapies which directly lower Lp(a) are undergoing clinical trials.

Gaps in the Care of Familial Hypercholesterolaemia in Australia: First Report From the National Registry.

BACKGROUND: Familial hypercholesterolaemia (FH) is under-diagnosed and under-treated worldwide, including Australia. National registries play a key role in identifying patients with FH, understanding gaps in care and advancing the science of FH to improve care for these patients. METHODS: The FH Australasia Network has established a national web-based registry to raise awareness of the condition, facilitate service planning and inform best practice and care services in Australia. We conducted a cross-sectional analysis of 1,528 FH adults enrolled in the registry from 28 lipid clinics. RESULTS: The mean age at enrolment was 53.4±15.1 years, 50.5% were male and 54.3% had undergone FH genetic testing, of which 61.8% had a pathogenic FH-causing gene variant. Only 14.0% of the cohort were family members identified through cascade testing. Coronary artery disease (CAD) was reported in 28.0% of patients (age of onset 49.0±10.5 years) and 64.9% had at least one modifiable cardiovascular risk factor. The mean untreated LDL-cholesterol was 7.4±2.5 mmol/L. 80.8% of patients were on lipid-lowering therapy with a mean treated LDL-cholesterol of 3.3±1.7 mmol/L. Among patients receiving lipid-lowering therapies, 25.6% achieved an LDL-cholesterol target of <2.5 mmol/L without CAD or <1.8 mmol/L with CAD. CONCLUSION: Patients in the national FH registry are detected later in life, have a high burden of CAD and risk factors, and do not achieve guideline-recommended LDL-cholesterol targets. Genetic and cascade testing are under-utilised. These deficiencies in care need to be addressed as a public health priority.

Optimising Secondary Prevention and Cardiac Rehabilitation for Atherosclerotic Cardiovascular Disease During the COVID-19 Pandemic: A Position Statement From the Cardiac Society of Australia and New Zealand (CSANZ).

BACKGROUND: The coronavirus disease 2019 (COVID-19) pandemic has introduced a major disruption to the delivery of routine health care across the world. This provides challenges for the use of secondary prevention measures in patients with established atherosclerotic cardiovascular disease (CVD). The aim of this Position Statement is to review the implications for effective delivery of secondary prevention strategies during the COVID-19 pandemic. CHALLENGES: The COVID-19 pandemic has introduced limitations for many patients to access standard health services such as visits to health care professionals, medications, imaging and blood tests as well as attendance at cardiac rehabilitation. In addition, the pandemic is having an impact on lifestyle habits and mental health. Taken together, this has the potential to adversely impact the ability of practitioners and patients to adhere to treatment guidelines for the prevention of recurrent cardiovascular events. RECOMMENDATIONS: Every effort should be made to deliver safe, ongoing access to health care professionals and the use of evidenced based therapies in individuals with CVD. An increase in use of a range of electronic health platforms has the potential to transform secondary prevention. Integrating research programs that evaluate the utility of these approaches may provide important insights into how to develop more optimal approaches to secondary prevention beyond the pandemic.

Status of PCSK9 Monoclonal Antibodies in Australia.

Proprotein convertase subtilisin/kexin type 9 (PCSK9) monoclonal antibodies (mAb) have progressed from showing marked low density lipoprotein cholesterol lowering in early phase trials through to reducing cardiovascular events in large clinical outcome trials. Recently in Australia, the indication for evolocumab has been expanded to include both heterozygous and homozygous familial hypercholesterolaemia under the Pharmaceutical Benefits Scheme (PBS). With prices remaining high currently their use in non-familial hypercholesterolaemia in Australia remains by private prescription only at this stage. This manuscript summarises the major outcomes trials of the PCSK9 mAbs and the secondary analyses that have assessed their benefits in high risk patient groups, and describes the consensus of authors on which patients would most likely benefit from PCSK9 mAb therapy.

The association between post-traumatic stress disorder and coronary artery disease: a meta-analysis.

OBJECTIVES: There are some psychosocial factors that have similar importance to biological factors in the genesis of coronary diseases. However, reasons for high rates of coronary heart disease in individuals with post-traumatic stress disorder (PTSD) are yet to be fully elucidated. Using a meta-analysis, we investigated the longitudinal relationship between PTSD and coronary heart disease (CHD) as an independent factor in the aetiology of CHD. METHODS: The databases of Medline, EBSCOhost and Psychoinfo were electronically searched for relevant articles. RESULTS: The pooled hazard ratio (HR) for the magnitude of the relationship between PTSD and CHD was an HR of 1.61, and p-value of p < 0.0005, 95% confidence interval (CI) [1.46-1.77] before adjustment for depression in nine studies ( N = 151,144) that met inclusion criteria. The HR estimates for the seven depression-adjusted estimates was 1.46, and a p-value of p < 0.0005, 95% CI[0.26-1.69]. CONCLUSIONS: This study demonstrates an association between CHD and PTSD.

PTSD symptoms associated with myocardial infarction: practical clinical implications.

OBJECTIVES: Several studies have demonstrated a link between post-traumatic stress disorder and myocardial infarction. We aim to determine what phenotypic features or symptom profile associated with cardiovascular disease may help with early detection and intervention. METHODS: This is a cross-sectional study. The study population comprises trauma-exposed Vietnam War veterans. RESULTS: Variables significantly associated with myocardial infarction from the bivariate analysis were avoidance memories, avoidance reminders and sleep disturbance. These variables were put into a logistic regression with known risk factors for myocardial infarction. Only sleep disturbance retained its effect, with a p-value of 0.015. CONCLUSIONS: It is concluded that sleep disturbance may be a modifiable risk factor in the treatment and prevention of myocardial infarction.

Long-Term Effectiveness and Safety of Pravastatin in Patients With Coronary Heart Disease: Sixteen Years of Follow-Up of the LIPID Study.

BACKGROUND: We aimed to assess the long-term effects of treatment with statin therapy on all-cause mortality, cause-specific mortality, and cancer incidence from extended follow-up of the Long-term Intervention with Pravastatin in Ischemic Disease (LIPID) trial. METHODS AND RESULTS: LIPID initially compared pravastatin and placebo over 6 years in 9014 patients with previous coronary heart disease. After the double-blind period, all patients were offered open-label statin therapy. Data were obtained over a further 10 years from 7721 patients, by direct contact for 2 years, by questionnaires thereafter, and from mortality and cancer registries. During extended follow-up, 85% assigned pravastatin and 84% assigned placebo took statin therapy. Patients assigned pravastatin maintained a significantly lower risk of death from coronary heart disease (relative risk [RR] 0.89; 95% confidence interval [CI], 0.81-0.97; P=0.009), from cardiovascular disease (RR, 0.88; 95% CI, 0.81-0.95; P=0.002), and from any cause (RR, 0.91; 95% CI, 0.85-0.97; absolute risk reduction, 2.6%; P=0.003).Cancer incidence was similar by original treatment group during the double-blind period (RR, 0.94; 95% CI, 0.82-1.08; P=0.41), later follow-up (RR, 1.02; 95% CI, 0.91-1.14; P=0.74), and overall (RR, 0.99; 95% CI, 0.91-1.08; P=0.83). There were no significant differences in cancer mortality, or in the incidence of organ-specific cancers. Cancer findings were confirmed in a meta-analysis with other large statin trials with extended follow-up. CONCLUSIONS: In LIPID, the absolute survival benefit from 6 years of pravastatin treatment appeared to be maintained for the next 10 years, with a similar risk of death among survivors in both groups after the initial period. Treatment with statins does not influence cancer or death from noncardiovascular causes during long-term follow-up.

Physical comorbidities of post-traumatic stress disorder in Australian Vietnam War veterans.

OBJECTIVE: To determine whether the prevalence of physical comorbidities in Australian Vietnam War veterans with post-traumatic stress disorder (PTSD) is higher than in trauma-exposed veterans without PTSD. DESIGN, SETTING AND PARTICIPANTS: Cross-sectional analysis of the health status (based on self-reported and objective clinical assessments) of 298 Australian Vietnam War veterans enrolled by the Gallipoli Medical Research Institute (Brisbane) during February 2014 - July 2015, of whom 108 were confirmed as having had PTSD and 106 served as trauma-exposed control participants.Main outcomes and measures: Diagnostic psychiatric interview and psychological assessments determined PTSD status, trauma exposure, and comorbid psychological symptoms. Demographic data, and medical and sleep history were collected; comprehensive clinical examination, electrocardiography, spirometry, liver transient elastography, and selected pathology assessments and diagnostic imaging were performed. Outcomes associated with PTSD were identified; regression analysis excluded the effects of potentially confounding demographic and risk factors and comorbid symptoms of depression and anxiety. RESULTS: The mean total number of comorbidities was higher among those with PTSD (17.7; SD, 6.1) than in trauma-exposed controls (14.1; SD, 5.2; P < 0.001). For 24 of 171 assessed clinical outcomes, morbidity was greater in the PTSD group, including for conditions of the gastrointestinal, hepatic, cardiovascular, and respiratory systems, sleep disorders, and laboratory pathology measures. In regression analyses including demographic factors, PTSD remained positively associated with 17 adverse outcomes; after adjusting for the severity of depressive symptoms, it remained significantly associated with ten. CONCLUSION: PTSD in Australian Vietnam veterans is associated with comorbidities in several organ systems, independent of trauma exposure. A comprehensive approach to the health care of veterans with PTSD is needed.

Clinical Profile of Statin Intolerance in the Phase 3 GAUSS-2 Study.

PURPOSE: Recent evidence suggests that statin intolerance may be more common than reported in randomized trials. However, the statin-intolerant population is not well characterized. The goal of this report is to characterize the population enrolled in the phase 3 Goal Achievement after Utilizing an anti-PCSK9 antibody in Statin Intolerant Subjects Study (GAUSS-2; NCT 01763905). METHODS: GAUSS-2 compared evolocumab, a fully human monoclonal antibody to proprotein convertase subtilisin/kexin type 9 (PCSK9) to ezetimibe in hypercholesterolemic patients who discontinued statin therapy due to statin-associated muscle symptoms (SAMS). GAUSS-2 was a 12-week, double-blind, placebo-controlled, randomized study that enrolled patients with elevated LDL-C who were either not on a statin or able to tolerate only a low-dose due to SAMS. Patients had received ≥2 statins and were unable to tolerate any statin dose or increase in dose above a specified weekly dose due to SAMS. RESULTS: Three hundred seven patients (mean [SD] age, 62 [10] years; 54 % males) were randomized 2:1 (evolocumab:ezetimibe). Mean (SD) LDL-C was 4.99 (1.51) mmol/L. Patients had used ≥2 (100 %), ≥3 (55 %), or ≥4 (21 %) statins. Coronary artery disease was present in 29 % of patients. Statin-intolerant symptoms were myalgia in 80 % of patients, weakness in 39 %, and more serious complications in 20 %. In 98 % of patients, SAMS interfered with normal daily activity; in 52 %, symptoms precluded moderate exertion. CONCLUSION: Evaluation of the GAUSS-2 trial population of statin-intolerant patients demonstrates that most patients were high risk with severely elevated LDL-C and many had statin-associated muscle symptoms that interfered with their quality of life.

Bioorthogonal mimetics of palmitoyl-CoA and myristoyl-CoA and their subsequent isolation by click chemistry and characterization by mass spectrometry reveal novel acylated host-proteins modified by HIV-1 infection.

Protein acylation plays a critical role in protein localization and function. Acylation is essential for human immunodeficiency virus 1 (HIV-1) assembly and budding of HIV-1 from the plasma membrane in lipid raft microdomains and is mediated by myristoylation of the Gag polyprotein and the copackaging of the envelope protein is facilitated by colocalization mediated by palmitoylation. Since the viral accessory protein NEF has been shown to alter the substrate specificity of myristoyl transferases, and alter cargo trafficking lipid rafts, we hypothesized that HIV-1 infection may alter protein acylation globally. To test this hypothesis, we labeled HIV-1 infected cells with biomimetics of acyl azides, which are incorporated in a manner analogous to natural acyl-Co-A. A terminal azide group allowed us to use a copper catalyzed click chemistry to conjugate the incorporated modifications to a number of substrates to carry out SDS-PAGE, fluorescence microscopy, and enrichment for LC-MS/MS. Using LC-MS/MS, we identified 103 and 174 proteins from the myristic and palmitic azide enrichments, with 27 and 45 proteins respectively that differentiated HIV-1 infected from uninfected cells. This approach has provided us with important insights into HIV-1 biology and is widely applicable to many virological systems.

Complex N-linked glycans serve as a determinant for exosome/microvesicle cargo recruitment.

Exosomes, also known as microvesicles (EMVs), are nano-sized membranous particles secreted from nearly all mammalian cell types. These nanoparticles play critical roles in many physiological processes including cell-cell signaling, immune activation, and suppression and are associated with disease states such as tumor progression. The biological functions of EMVs are highly dependent on their protein composition, which can dictate pathogenicity. Although some mechanisms have been proposed for the regulation of EMV protein trafficking, little attention has been paid to N-linked glycosylation as a potential sorting signal. Previous work from our laboratory found a conserved glycan signature for EMVs, which differed from that of the parent cell membranes, suggesting a potential role for glycosylation in EMV biogenesis. In this study, we further explore the role of glycosylation in EMV protein trafficking. We identify EMV glycoproteins and demonstrate alteration of their recruitment as a function of their glycosylation status upon pharmacological manipulation. Furthermore, we show that genetic manipulation of the glycosylation levels of a specific EMV glycoprotein, EWI-2, directly impacts its recruitment as a function of N-linked glycan sites. Taken together, our data provide strong evidence that N-linked glycosylation directs glycoprotein sorting into EMVs.

A bioinformatics approach for integrated transcriptomic and proteomic comparative analyses of model and non-sequenced anopheline vectors of human malaria parasites.

Malaria morbidity and mortality caused by both Plasmodium falciparum and Plasmodium vivax extend well beyond the African continent, and although P. vivax causes between 80 and 300 million severe cases each year, vivax transmission remains poorly understood. Plasmodium parasites are transmitted by Anopheles mosquitoes, and the critical site of interaction between parasite and host is at the mosquito's luminal midgut brush border. Although the genome of the "model" African P. falciparum vector, Anopheles gambiae, has been sequenced, evolutionary divergence limits its utility as a reference across anophelines, especially non-sequenced P. vivax vectors such as Anopheles albimanus. Clearly, technologies and platforms that bridge this substantial scientific gap are required in order to provide public health scientists with key transcriptomic and proteomic information that could spur the development of novel interventions to combat this disease. To our knowledge, no approaches have been published that address this issue. To bolster our understanding of P. vivax-An. albimanus midgut interactions, we developed an integrated bioinformatic-hybrid RNA-Seq-LC-MS/MS approach involving An. albimanus transcriptome (15,764 contigs) and luminal midgut subproteome (9,445 proteins) assembly, which, when used with our custom Diptera protein database (685,078 sequences), facilitated a comparative proteomic analysis of the midgut brush borders of two important malaria vectors, An. gambiae and An. albimanus.

Indications for Omega-3 Long Chain Polyunsaturated Fatty Acid in the Prevention and Treatment of Cardiovascular Disease.

BACKGROUND: The National Heart Foundation of Australia (NHFA) 2008 review on omega-3 long-chain polyunsaturated fatty acids (LCPUFA) made recommendations with respect to supplementation for primary and secondary prevention of cardiovascular disease. Since then, new findings have been published regarding the relationship between omega-3 polyunsaturated fatty acids, including supplementation, and cardiovascular health. METHODS: A literature search was undertaken in PubMed and Medline, for literature published between January 1, 2007 and August 31, 2013. RESULTS AND CONCLUSIONS: A total of eight research questions were developed and, using the National Health and Medical Research Council's evidence assessment framework, conclusions were made in relation to dietary intake of fish and omega-3 LCPUFA for cardiovascular health. In the evidence published since 2007, this summary of evidence concludes that dietary intake of fish was found to be mostly consistent with respect to protection from heart disease and stroke. Higher fish intake was associated with lower incident rates of heart failure in addition to lower sudden cardiac death, stroke and myocardial infarction. In relation to omega-3 LCPUFA supplementation, neither a beneficial nor adverse effect was demonstrated in primary or secondary prevention of coronary heart disease (CHD). Although the evidence continues to be positive for the role of omega-3 LCPUFA in the treatment of hypertriglyceridaemia and a modest positive benefit in heart failure. No further evidence was found to support the consumption of 2g alpha-linolenic acid (ALA)/day over the current Australian guidelines for 1 g/day.

Clinical Exercise Stress Testing in Adults (2014).

This position paper provide guidelines on the minimum requirements of both personnel and equipment for the safe performance of clinical exercise electrocardiography, and for the adequate interpretation and assessment of results. This document was originally developed by Professor Ben Freedman and members of the Rehabilitation, Exercise and Prevention Working Group in 1996. It has been recently reviewed by a Working Group chaired by Associate Professor David Colquhoun. The resulting, revised Statement was considered by the Continuing Education and Recertification Committee and ratified at the CSANZ Board meeting held on 1st August 2014.

Plasma lipoprotein(a) concentration predicts future coronary and cardiovascular events in patients with stable coronary heart disease.

OBJECTIVE: Association between lipoprotein(a) (Lp(a)) level and a first-ever coronary (CHD) event is recognized. Less is evident in patients with overt CHD and stable symptoms in whom we investigated associations between Lp(a) and future events. APPROACH AND RESULTS: Relationships between Lp(a) concentration and CHD and cardiovascular disease outcomes during 6 years' median follow-up were evaluated in the Long-Term Intervention with Pravastatin in Ischaemic Disease (LIPID) study. Lp(a) concentrations were measured in plasma from 7863 patients who had sustained a previous coronary event and been randomized to pravastatin or placebo. Lp(a) levels were categorized by lowest half, third quartile, 75th to 90th percentile, and highest decile. The prognostic value of Lp(a) on outcomes was assessed by fitting a Cox proportional-hazards model after adjustment for other risk factors and baseline cardiovascular disorders. The prognostic value of a change in Lp(a) at year 1 categorized by quartiles was assessed using Cox regression in a landmark model incorporating the above factors and baseline levels. Baseline Lp(a) concentration was associated with total CHD events (P<0.001), total cardiovascular disease events (P=0.002), and coronary events (P=0.03). Greatest risk occurred at >73 mg/dL, upper decile. For events after year 1, an increase in Lp(a) at 1 year was associated with adverse outcomes for total CHD events and total cardiovascular disease events (P=0.002 each). CONCLUSIONS: In the LIPID study, baseline Lp(a) was associated with future cardiovascular disease and CHD events. Increased Lp(a) concentrations after 1 year were also associated with future events, supporting measurement of Lp(a) for risk assessment of patients with known CHD.

On the nature of partial agonism in the nicotinic receptor superfamily.

Partial agonists are ligands that bind to receptors but produce only a small maximum response even at concentrations where all receptors are occupied. In the case of ligand-activated ion channels, it has been supposed since 1957 that partial agonists evoke a small response because they are inefficient at eliciting the change of conformation between shut and open states of the channel. We have investigated partial agonists for two members of the nicotinic superfamily-the muscle nicotinic acetylcholine receptor and the glycine receptor-and find that the open-shut reaction is similar for both full and partial agonists, but the response to partial agonists is limited by an earlier conformation change ('flipping') that takes place while the channel is still shut. This has implications for the interpretation of structural studies, and in the future, for the design of partial agonists for therapeutic use.