The Effect of Darapladib on Plasma Lipoprotein-Associated Phospholipase A2 Activity and Cardiovascular Biomarkers in Patients With Stable Coronary Heart Disease or Coronary Heart Disease Risk Equivalent

Intravascular imaging assessment of pharmacotherapies targeting atherosclerosis: advantages and limitations in predicting their prognostic implications

Intravascular imaging has been often used over the recent years to examine the efficacy of emerging therapies targeting plaque evolution. Serial intravascular ultrasound, optical coherence tomography, or near-infrared spectroscopy-intravascular ultrasound studies have allowed us to evaluate the effects of different therapies on plaque burden and morphology, providing unique mechanistic insights about the mode of action of these treatments. Plaque burden reduction, a decrease in necrotic core component or macrophage accumulation-which has been associated with inflammation-and an increase in fibrous cap thickness over fibroatheromas have been used as surrogate endpoints to assess the value of several drugs in inhibiting plaque evolution and improving clinical outcomes. However, some reports have demonstrated weak associations between the effects of novel treatments on coronary atheroma and composition and their prognostic implications. This review examines the value of invasive imaging in assessing pharmacotherapies targeting atherosclerosis. It summarizes the findings of serial intravascular imaging studies assessing the effects of different drugs on atheroma burden and morphology and compares them with the results of large-scale trials evaluating their impact on clinical outcome. Furthermore, it highlights the limited efficacy of established intravascular imaging surrogate endpoints in predicting the prognostic value of these pharmacotherapies and introduces alternative imaging endpoints based on multimodality/hybrid intravascular imaging that may enable more accurate assessment of the athero-protective and prognostic effects of emerging therapies.

Lp-PLA2 (Lipoprotein-Associated Phospholipase A2) Deficiency Lowers Cholesterol Levels and Protects Against Atherosclerosis in Rabbits

BACKGROUND

Elevated plasma Lp-PLA₂ (lipoprotein-associated phospholipase A₂) activity is closely associated with an increased risk of cardiovascular events. However, whether and how Lp-PLA₂ is directly involved in the pathogenesis of atherosclerosis is still unclear. To examine the hypothesis that Lp-PLA₂ could be a potential preventative target of atherosclerosis, we generated Lp-PLA₂ knockout rabbits and investigated the pathophysiological functions of Lp-PLA₂.

METHODS

Lp-PLA₂ knockout rabbits were generated using CRISPR/Cas9 system to assess the role of Lp-PLA₂ in plasma lipids regulation and identify its underlying molecular mechanisms. Homozygous knockout rabbits along with wild-type rabbits were fed a cholesterol-rich diet for up to 14 weeks and their atherosclerotic lesions were compared. Moreover, the effects of Lp-PLA₂ deficiency on the key cellular behaviors in atherosclerosis were assessed in vitro.

RESULTS

When rabbits were fed a standard diet, Lp-PLA₂ deficiency led to a significant reduction in plasma lipids. The decreased protein levels of SREBP2 (sterol regulatory element-binding protein 2) and HMGCR (3-hydroxy-3-methylglutaryl coenzyme A reductase) in livers of homozygous knockout rabbits indicated that the cholesterol biosynthetic pathway was impaired with Lp-PLA₂ deficiency. In vitro experiments further demonstrated that intracellular Lp-PLA₂ efficiently enhanced SREBP2-related cholesterol biosynthesis signaling independently of INSIGs (insulin-induced genes). When fed a cholesterol-rich diet, homozygous knockout rabbits exhibited consistently lower level of hypercholesterolemia, and their aortic atherosclerosis lesions were significantly reduced by 60.2% compared with those of wild-type rabbits. The lesions of homozygous knockout rabbits were characterized by reduced macrophages and the expression of inflammatory cytokines. Macrophages of homozygous knockout rabbits were insensitive to M1 polarization and showed reduced DiI-labeled lipoprotein uptake capacity compared with wild-type macrophages. Lp-PLA₂ deficiency also inhibited the adhesion between monocytes and endothelial cells.

CONCLUSIONS

These results demonstrate that Lp-PLA₂ plays a causal role in regulating blood lipid homeostasis and Lp-PLA₂ deficiency protects against dietary cholesterol-induced atherosclerosis in rabbits. Lp-PLA₂ could be a potential target for the prevention of atherosclerosis.

Oxidized phospholipids and lipoprotein-associated phospholipase A2 (Lp-PLA2 ) in atherosclerotic cardiovascular disease: An update

Inflammation and oxidative stress conditions lead to a variety of oxidative modifications of lipoprotein phospholipids implicated in the occurrence and development of atherosclerotic lesions. Lipoprotein-associated phospholipase A2 (Lp-PLA2 ) is established as an independent risk biomarker of atherosclerosis-related cardiovascular disease (ASCVD) and mediates vascular inflammation through the regulation of lipid metabolism in the blood and in atherosclerotic lesions. Lp-PLA2 is associated with low- and high-density lipoproteins and Lipoprotein (a) in human plasma and specifically hydrolyzes oxidized phospholipids involved in oxidative stress modification. Several oxidized phospholipids (OxPLs) subspecies can be detoxified through enzymatic degradation by Lp-PLA2 activation, forming lysophospholipids and oxidized non-esterified fatty acids (OxNEFAs). Lysophospholipids promote the expression of adhesion molecules, stimulate cytokines production (TNF-α, IL-6), and attract macrophages to the arterial intima. The present review article discusses new data on the functional roles of OxPLs and Lp-PLA2 associated with lipoproteins.

Integrated analysis of single-cell and bulk RNA sequencing reveals pro-fibrotic PLA2G7high macrophages in pulmonary fibrosis

Pulmonary fibrosis (PF) is the pathological change of end-stage interstitial lung diseases with high mortality and limited therapeutic options. Lung macrophages have distinct subsets with divergent functions, and play critical roles in the pathogenesis of PF. In this study, integrative analysis of lung single-cell and bulk RNA-seq data from patients with fibrotic hypersensitivity pneumonitis and idiopathic pulmonary fibrosis was utilized to identify particular macrophage subsets during the development of PF. We find a specific macrophage subpopulation highly expressing PLA2G7 in fibrotic lungs. We performed additional single-cell RNA-seq analysis to identify analogous macrophage population in bleomycin (BLM)-induced mouse pulmonary fibrosis models. By in vitro and in vivo experiments, we further reveal the pro-fibrotic role for this PLA2G7^high macrophage subset in fibroblast-to-myofibroblast transition (FMT) during pulmonary fibrosis. PLA2G7 promotes FMT via LPC/ATX/LPA/LPA2 axis in macrophages. Moreover, PLA2G7 is regulated by STAT1, and pharmacological inhibition of PLA2G7 by Darapladib ameliorates pulmonary fibrosis in BLM-induced mice. The results of this study support the view that PLA2G7^high macrophage subpopulation contributes importantly to the pathogenesis of PF, which provides a potential way for targeted therapy.

The benefit of exercise rehabilitation guided by 6-minute walk test on lipoprotein-associated phospholipase A2 in patients with coronary heart disease undergoing percutaneous coronary intervention: a prospective randomized controlled study

Background

Lipoprotein-associated phospholipase A2 (Lp-PLA2) has been taken as a biomarker of inflammation in patients with acute coronary diseases. Regular exercise rehabilitation could attenuate inflammation and promote the rehabilitation of coronary heart disease (CHD). The level of Lp-PLA2 is negatively correlated with 6-min walk test (6-MWT). The exercise prescription of appropriate intensity is the basis of exercise rehabilitation. 6-MWT is associated with maximal oxygen consumption, and can be used to determine the intensity of exercise prescription guiding patients how to do exercise rehabilitation. The aim of this study was to observe the benefit of 6-MWT guided exercise rehabilitation on the level of Lp-PLA2 in patients with CHD undergoing percutaneous coronary intervention (PCI).

Methods

We prospectively, consecutively enrolled 100 patients between Dec 2018 and Dec 2020 in the fourth ward of the Department of Cardiology, Yuebei People's Hospital Affiliated to Shantou University. Eligible patients were 1:1 divided into Group A, with no exercise rehabilitation, and Group B, with regular exercise rehabilitation, using random number table method of simple randomization allocation. Clinical data such as general information, the profile of lipids and the level of Lp-PLA2 were collected at baseline and at 12-week follow-up.

Results

There were no statistically significant differences of the percentages of gender, hypertension, type-2 diabetes mellitus (T2DM), the profile of lipids and level of Lp-PLA2 between the groups at baseline (P > 0.05). The level of Lp-PLA2 decreased at 12-week follow-up, moreover, the decline of the Lp-PLA2 level in Group B was more significant than that in Group A (t = 2.875, P = 0.005). Multivariate linear regression analysis indicated that exercise rehabilitation was independently correlated with the level of Lp-PLA2 (β′ = − 0.258, t = − 2.542, P = 0.013).

Conclusion

Exercise rehabilitation for 12 weeks guided by 6-MWT can further reduce the level of LP-PLA2 in patients with CHD undergoing PCI.

Trial registration This trial was registered on the Chinese Clinical Trial Registry: ChiCTR2100048124, registered 3 July 2021- Retrospectively registered. The study protocol adheres to the CONSORT guidelines.

Oxidized phospholipids and lipoprotein(a): An update

Over the past few years, there has been an undiminished interest in lipoprotein(a) [Lp(a)] and oxidized phospholipids (OxPLs), mainly carried on this lipoprotein. Elevated Lp(a) has been established as an independent causal risk factor for cardiovascular disease. OxPLs play an important role in atherosclerosis. The main questions that remain to be answered, however, is to what extent OxPLs contribute to the atherogenicity of Lp(a), what effect hypolipidaemic medications may have on their levels and the potential clinical benefit of their reduction. This narrative review aimed to summarize currently available data on OxPLs and cardiovascular risk, as well as the effect of established and emerging hypolipidaemic medications on Lp(a)-OxPLs.

Inflammatory Markers in Cardiovascular Disease; Lessons Learned and Future Perspectives

BACKGROUND

Cardiovascular disease (CVD) still remains the leading cause of morbidity and mortality worldwide. It is now established that inflammation plays a crucial role in atherosclerosis and atherothrombosis, and thus, it is closely linked to cardiovascular disease.

OBJECTIVE

The aim of the present review is to summarize and critically appraise the most relevant evidence regarding the potential use of inflammatory markers in the field of CVD.

METHODS

We conducted a comprehensive research of the relevant literature, searching MEDLINE from its inception until November 2018, primarily for meta-analyses, randomized controlled trials and observational studies.

RESULTS

Established markers of inflammation, mainly C-reactive protein, have yielded significant results both for primary and secondary prevention of CVD. Newer markers, such as lipoprotein-associated phospholipase A2, lectin-like oxidized low-density lipoprotein receptor-1, cytokines, myeloperoxidase, cell adhesion molecules, matrix metalloproteinases, and the CD40/CD40 ligand system, have been largely evaluated in human studies, enrolling both individuals from the general population and patients with established CVD. Some markers have yielded conflicting results; however, others are now recognized not only as promising biomarkers of CVD, but also as potential therapeutic targets, establishing the role of anti-inflammatory and pleiotropic drugs in CVD.

CONCLUSION

There is significant evidence regarding the role of consolidated and novel inflammatory markers in the field of diagnosis and prognosis of CVD. However, multimarker model assessment, validation of cut-off values and cost-effectiveness analyses are required in order for those markers to be integrated into daily clinical practice.

Leukocyte Trafficking via Lymphatic Vessels in Atherosclerosis

In recent years, lymphatic vessels have received increasing attention and our understanding of their development and functional roles in health and diseases has greatly improved. It has become clear that lymphatic vessels are critically involved in acute and chronic inflammation and its resolution by supporting the transport of immune cells, fluid, and macromolecules. As we will discuss in this review, the involvement of lymphatic vessels has been uncovered in atherosclerosis, a chronic inflammatory disease of medium- and large-sized arteries causing deadly cardiovascular complications worldwide. The progression of atherosclerosis is associated with morphological and functional alterations in lymphatic vessels draining the diseased artery. These defects in the lymphatic vasculature impact the inflammatory response in atherosclerosis by affecting immune cell trafficking, lymphoid neogenesis, and clearance of macromolecules in the arterial wall. Based on these new findings, we propose that targeting lymphatic function could be considered in conjunction with existing drugs as a treatment option for atherosclerosis.

Imaging and Targeting Coronary Artery Inflammation

Significance: Coronary artery disease (CAD) continues to be a leading cause of morbidity and mortality across the world despite significant progress in the prevention, diagnosis, and treatment of atherosclerotic disease. Recent Advances: The focus of the cardiovascular community has shifted toward seeking a better understanding of the inflammatory mechanisms driving residual CAD risk that is not modulated by current therapies. Significant progress has been achieved in revealing both proinflammatory and anti-inflammatory mechanisms, and how shift of the balance in favor of the former can drive the development of disease. Critical Issues: Advances in the noninvasive detection of coronary artery inflammation have been forthcoming. These advances include multiple imaging modalities, with novel applications of computed tomography both with and without positron emission tomography, and experimental ultrasound techniques. These advances will enable better selection of patients for anti-inflammatory treatments and assessment of treatment response. The rapid advancement in pharmaceutical design has enabled the production of specific antibodies against inflammatory pathways of atherosclerosis, with modest success to date. The pursuit of demonstrating the efficacy and safety of novel anti-inflammatory and/or proinflammatory resolution therapies for atherosclerotic CAD has become a major focus. Future Directions: This review seeks to provide an update of the latest evidence of all three of these highly related but disparate areas of inquiry: Our current understanding of the key mechanisms by which inflammation contributes to coronary artery atherosclerosis, the evidence for noninvasive assessment of coronary artery inflammation, and finally, the evidence for targeted therapies to treat coronary inflammation for the reduction of CAD risk. Antioxid. Redox Signal. 34, 1217-1243.

Alternative strategies in cardiac preclinical research and new clinical trial formats

An efficient and safe drug development process is crucial for the establishment of new drugs on the market aiming to increase quality of life and life-span of our patients. Despite technological advances in the past decade, successful launches of drug candidates per year remain low. We here give an overview about some of these advances and suggest improvements for implementation to boost preclinical and clinical drug development with a focus on the cardiovascular field. We highlight advantages and disadvantages of animal experimentation and thoroughly review alternatives in the field of three-dimensional cell culture as well as preclinical use of spheroids and organoids. Microfluidic devices and their potential as organ-on-a-chip systems, as well as the use of living animal and human cardiac tissues are additionally introduced. In the second part, we examine recent gold standard randomized clinical trials and present possible modifications to increase lead candidate throughput: adaptive designs, master protocols, and drug repurposing. In silico and N-of-1 trials have the potential to redefine clinical drug candidate evaluation. Finally, we briefly discuss clinical trial designs during pandemic times.

Lipoprotein-associated phospholipase A2 levels, endothelial dysfunction and arterial stiffness in patients with stable coronary artery disease

BACKGROUND

Lipoprotein-associated Phospholipase A2 (Lp-PLA2), can exert proinflammatory as well as proatherogenic properties on the vascular wall. The current study sought to evaluate the influence of high Lp-PLA2 levels on indices of arterial wall properties in patients with stable coronary artery disease (CAD).

METHODS

Three hundred seventy-four consecutive patients with stable CAD (mean age 61 ± 11 years, 89% males) were enrolled in this single-center cross-sectional study. Flow-mediated dilation (FMD) was used to assess endothelial function and augmentation index (AIx) of the central aortic pressure was used to assess reflected waves. ELISA was used to determine Lp-PLA2 serum levels.

RESULTS

After dividing the participants in 3 equal groups based on the tertiles of circulating Lp-PLA2 values, no significant differences were demonstrated between those in the 3rd tertile with Lp-PLA2 values > 138 μg/L, in the 2nd tertile with Lp-PLA2 values between 101 and 138 μg/L and in the 1st tertile (Lp-PLA2 values < 101 μg/L) regarding age, male gender, smoking habits, family history of CAD or history of a previous myocardial infarction, diabetes mellitus, arterial hypertension, hyperlipidemia, duration of CAD and treatment with relevant medication. Importantly, subjects with Lp-PLA2 values in the highest tertile, had significantly reduced FMD values compared to the middle and lower tertile (4.43 ± 2.37% vs. 4.61 ± 1.97% vs. 5.20 ± 2.52% respectively, P = 0.03). Patients in the highest tertile of Lp-PLA2 values had significantly higher AIx values (24.65 ± 8.69% vs. 23.33 ± 9.65%, P = 0.03), in comparison to the lowest tertile, with Lp-PLA2 values < 101 μg/L. A linear regression analysis showed that Lp-PLA2 values > 138 μg/L negatively correlated to FMD [b = - 0.45 (95% CI: - 0.79 - -0.11), P = 0.01] and AIx values [b = 1.81 (95% CI: 0.57-3.05), P < 0.001] independently of cofounders like gender, age, diabetes mellitus, arterial hypertension, dyslipidemia, smoking habits, family history of CAD, history of previous myocardial infarction, serum glucose, circulating lipid levels, duration of CAD, antihypertensive medication, antidiabetic drugs, statin therapy and treatment with β-blockers.

CONCLUSIONS

Elevated Lp-PLA2 levels relate to endothelial dysfunction and arterial stiffness in patients with stable CAD independently from classical risk factors for CAD, statin use, antihypertensive treatment, and duration of the disease.

On the present and future role of Lp-PLA2 in atherosclerosis-related cardiovascular risk prediction and management

Circulating concentration and activity of secretory phospholipase A₂ (sPLA₂) and lipoprotein-associated phospholipase A₂ (Lp-PLA₂) have been proven as biomarkers of increased risk of atherosclerosis-related cardiovascular disease (ASCVD). Lp-PLA₂ might be part of the atherosclerotic process and may contribute to plaque destabilisation through inflammatory activity within atherosclerotic lesions. However, all attempts to translate the inhibition of phospholipase into clinically beneficial ASCVD risk reduction, including in randomised studies, by either non-specific inhibition of sPLA₂ (by varespladib) or specific Lp-PLA₂ inhibition by darapladib, unexpectedly failed. This gives us a strong imperative to continue research aimed at a better understanding of how Lp-PLA₂ and sPLA₂ regulate vascular inflammation and atherosclerotic plaque development. From the clinical viewpoint there is a need to establish and validate the existing and emerging novel anti-inflammatory therapeutic strategies to fight against ASCVD development, by using potentially better animal models and differently designed clinical trials in humans.

The recent effects of small dose of folic acid on lipoprotein-associated phospholipase A2 and systolic blood pressure variability in coronary heart disease patients with hyperhomocysteinemia: A single-center prospective cohort study

To Investigate the recent effects of small dose of folic acid on lipoprotein-associated phospholipase A2 (LP-PLA2) and systolic blood pressure variability in coronary heart disease (CHD) patients with hyperhomocysteinemia.In this prospective cohort study, a total of 167 CHD patients with hyperhomocysteinemia were consecutively enrolled, and they were divided into Group A (without folic acid intervention, n = 99), Group B (with 0.4 mg of folic acid intervention, n = 34), Group C (0.8 mg of folic acid intervention, n = 34). General information, fasting blood glucose, and blood lipid, folic acid, homocysteine, Lp-PLA2, and blood pressure variability were compared among 3 groups. The above indicators were reviewed after 3 months of treatment.There were no statistically significant differences of age, gender, blood pressure, incidence of type 2 diabetes mellitus, fasting blood glucose, folic acid, homocysteine, Lp-PLA2, total cholesterol, 3 acyl glycerin, apolipoprotein B, lipoprotein (a), high density lipoprotein cholesterol, and low density lipoprotein cholesterol were found among 3 groups (P > .05); however, after being treated for 3 months, there was statistically significant difference in folic acid among 3 groups (P < .05), there was statistically significant difference in apolipoprotein A between Group A and Group B (t = 0.505, P = .039), and also between Group A and Group C (t = 0.052, P = .017). There were statistically significant differences in Lp-PLA2 (t = 24.320, P = .016) and systolic blood pressure variability (t = 0.154, P = .018) between Group A and Group C.For CHD patients with hyperhomocysteinemia, the higher dose (0.8 mg) of folic acid supplement was beneficial for increasing the apolipoprotein A, reducing the Lp-PLA2, and improving the systolic blood pressure variation, which might help to improve the prognosis in these patients.

Active site competition is the mechanism for the inhibition of lipoprotein-associated phospholipase A2 by detergent micelles or lipoproteins and for the efficacy reduction of darapladib

Lipoprotein associated phospholipase A₂ (Lp-PLA₂) has been characterized for its interfacial activation as well as inhibition by detergent micelles and lipoprotein particles. The enzyme has been shown to bind on the surfaces of hydrophobic aggregates, such as detergent micelles, lipoprotein particles and even polystyrene latex nanobeads. Binding to hydrophobic aggregates stimulates the activity of Lp-PLA₂ but may not be the necessary step for catalysis. However, at higher concentrations, detergent micelles, latex nanobeads or lipoprotein particles inhibit Lp-PLA₂ possibly by blocking the access of substrates to the active site. The competition mechanism also blocks inhibitors such as darapladib binding to Lp-PLA₂ and reduces the efficacy of the drug. Darapladib has very low solubility and mainly exists in solutions as complexes with detergents or lipoprotein particles. The inhibition of Lp-PLA₂ by darapladib is dependent on many factors such as concentrations of detergents or lipoproteins, incubation time, as well as the order of mixing reaction components. The in vitro Lp-PLA₂ activity assays used in clinical studies may not accurately reflect the residual Lp-PLA₂ activity in vivo. Darapladib has been found mainly bound on HDL and albumin when it is incubated with human serum. However, Lp-PLA₂ is more sensitive to darapladib when bound on LDL and relatively resistant to darapladib when bound on HDL. Therefore, high cholesterol levels may decrease the efficacy of darapladip and cause the drug to be less effective in high risk patients. Our study will help to design better inhibitors for Lp-PLA₂. The discoveries also contribute to understanding the mechanism of interfacial activation and inhibition for Lp-PLA₂ and provide a new concept for researchers in building better kinetic model for interfacial enzymes.

Psychosocial Interventions and Immune System Function: A Systematic Review and Meta-analysis of Randomized Clinical Trials

IMPORTANCE

Recent estimates suggest that more than 50% of all deaths worldwide are currently attributable to inflammation-related diseases. Psychosocial interventions may represent a potentially useful strategy for addressing this global public health problem, but which types of interventions reliably improve immune system function, under what conditions, and for whom are unknown.

OBJECTIVE

To address this issue, we conducted a systematic review and meta-analysis of randomized clinical trials (RCTs) in which we estimated associations between 8 different psychosocial interventions and 7 markers of immune system function, and examined 9 potential moderating factors.

DATA SOURCES

PubMed, Scopus, PsycInfo, and ClinicalTrials.gov databases were systematically searched from February 1, 2017, to December 31, 2018, for all relevant RCTs published through December 31, 2018.

STUDY SELECTION

Eligible RCTs included a psychosocial intervention, immune outcome, and preintervention and postintervention immunologic assessments. Studies were independently examined by 2 investigators. Of 4621 studies identified, 62 were eligible and 56 included.

DATA EXTRACTION AND SYNTHESIS

Data were extracted and analyzed from January 1, 2019, to July 29, 2019. The Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guideline was followed. Data were extracted by 2 investigators who were blind to study hypotheses and analyses, and were then analyzed using robust variance estimation. Analysis included 8 psychosocial interventions (behavior therapy, cognitive therapy, cognitive behavior therapy [CBT], CBT plus additive treatment or mode of delivery that augmented the CBT, bereavement or supportive therapy, multiple or combined interventions, other psychotherapy, and psychoeducation), 7 immune outcomes (proinflammatory cytokine or marker levels, anti-inflammatory cytokine levels, antibody levels, immune cell counts, natural killer cell activity, viral load, and other immune outcomes), and 9 moderating factors (intervention type, intervention format, intervention length, immune marker type, basal vs stimulated markers, immune marker measurement timing, disease state or reason for treatment, age, and sex).

MAIN OUTCOMES AND MEASURES

The primary a priori outcomes were pretest-posttest-control (ppc) group effect sizes (ppc g) for the 7 immunologic outcomes investigated.

RESULTS

Across 56 RCTs and 4060 participants, psychosocial interventions were associated with enhanced immune system function (ppc g = 0.30, 95% CI, 0.21-0.40; t50.9 = 6.22; P < .001). Overall, being randomly assigned to a psychosocial intervention condition vs a control condition was associated with a 14.7% (95% CI, 5.7%-23.8%) improvement in beneficial immune system function and an 18.0% (95% CI, 7.2%-28.8%) decrease in harmful immune system function over time. These associations persisted for at least 6 months following treatment and were robust across age, sex, and intervention duration. These associations were most reliable for CBT (ppc g = 0.33, 95% CI, 0.19-0.47; t27.2 = 4.82; P < .001) and multiple or combined interventions (ppc g = 0.52, 95% CI, 0.17-0.88; t5.7 = 3.63; P = .01), and for studies that assessed proinflammatory cytokines or markers (ppc g = 0.33, 95% CI, 0.19-0.48; t25.6 = 4.70; P < .001).

CONCLUSIONS AND RELEVANCE

These findings suggest that psychosocial interventions are reliably associated with enhanced immune system function and may therefore represent a viable strategy for improving immune-related health.

Inflammation and cardiovascular diseases: lessons from seminal clinical trials

Inflammation has been long regarded as a key contributor to atherosclerosis. Inflammatory cells and soluble mediators play critical roles throughout arterial plaque development and accordingly, targeting inflammatory pathways effectively reduces atherosclerotic burden in animal models of cardiovascular (CV) diseases. Yet, clinical translation often led to inconclusive or even contradictory results. The Canakinumab Anti-inflammatory Thrombosis Outcome Study (CANTOS) followed by the Colchicine Cardiovascular Outcomes Trial (COLCOT) were the first two randomized clinical trials to convincingly demonstrate the effectiveness of specific anti-inflammatory treatments in the field of CV prevention, while other phase III trials-including the Cardiovascular Inflammation Reduction Trial one using methotrexate-were futile. This manuscript reviews the main characteristics and findings of recent anti-inflammatory Phase III trials in cardiology and discusses their similarities and differences in order to get further insights into the contribution of specific inflammatory pathways on CV outcomes. CANTOS and COLCOT demonstrated efficacy of two anti-inflammatory drugs (canakinumab and colchicine, respectively) in the secondary prevention of major adverse CV events (MACE) thus providing the first confirmation of the involvement of a specific inflammatory pathway in human atherosclerotic CV disease (ASCVD). Also, they highlighted the NOD-, LRR-, and pyrin domain-containing protein 3 inflammasome-related pathway as an effective therapeutic target to blunt ASCVD. In contrast, other trials interfering with a number of inflammasome-independent pathways failed to provide benefit. Lastly, all anti-inflammatory trials underscored the importance of balancing the risk of impaired host defence with an increase in infections and the prevention of MACE in CV patients with residual inflammatory risk.

Modulatory properties of cardiac and quercetin glycosides from Dacryodes edulis seeds during L-NAME-induced vascular perturbation

Background Numerous food wastes have been identified to possess potent bioactive compounds used for the treatment of several diseases. Therefore this study evaluated the potentials of cardiac and quercetin glycosides extracted from Dacryodes edulis seeds to reverse vascular and endothelial damage (VAED). Methods The glycoside composition of the seeds was extracted using standard methods and characterized by gas chromatography. We then recruited rats with L-NAME-induced VAED based on confirmatory biomarkers cardiac troponin (CnT), cellular adhesion molecule (VCAM-1), lipoprotein associated phospholipase A2 (Lp-PLA2), RAAS, VWF, endothelin, eNOx, and homocysteine. Only rats that showed total alterations of all biomarkers were recruited into the respective experimental groups and treated with either metaprolol succinate (met.su) + losartan or glycoside extracts of D. edulis seeds (NPSG). Results Chromatographic isolation of glycosides in the seed showed predominance of artemetin (1.59 mg/100 g), amygdalin (3.68 mg/100 g), digitoxin (19.21 mg/100 g), digoxin (27.23 mg/100 g), avicularin (133.59 mg/100 g), and hyperoside (481.76 mg/100 g). We observed decreased water intake and higher heart beats under vascular damage as the experiment progressed up to the fourth week. The met.su + losartan and H.D NPSG proved effective in restoring troponin, but both doses of NPSG normalized the VCAM-1 and RAAS activities excluding aldosterone and Lp-PLA2. Among the endothelial dysfunction biomarkers, H.D NPSG produced equivalent effects to met.su + losartan towards restoring the eNOx and VWF activities, but showed higher potency in normalizing the endothelin and Hcy levels. Conclusions We thus propose that the synergistic effect of the isolated glycosides from D. edulis shown in our study proved potent enough at high doses in treatment of vascular and endothelial dysfunction.

The relationship of lipoprotein-associated phospholipase A2 activity with the seriousness of coronary artery disease

BACKGROUND

The level of lipoprotein-associated phospholipase A2 (LP-PLA2) in serum is independently correlated to coronary artery diseases (CAD). The aim of the study was to determine whether LP-PLA2 activity is positively associated with the seriousness of CAD.

METHODS

Amount to 1056 patients suspected of having CAD underwent coronary angiography (CAG) to determine the seriousness of CAD. According to the amount of diseased coronary branches, the 1056 patients were split into three groups: single-vessel stenosis group, multiple-vessels stenosis group (> or = 2 diseased coronary branches),and control group (no diseased coronary branches). According to CAG results, electrocardiography, cardiac biomarker, and clinical presentation, all patients were split into four groups: acute myocardial infarction (AMI), unstable angina (UA), stable angina (SA), and control groups (excluding CAD). The activity of LP-PLA2 was compared statistically among the subgroups. Receiver operating characteristic analysis was applied to investigate the role of LP-PLA2 in evaluating the presence and seriousness of CAD.

RESULTS

The level of LP-PLA2 increased in line with the number of diseased coronary branches. The levels of LP-PLA2 in the AMI and UA groups were observably higher when compared with the control and SA groups. LP-PLA2 had 75.6% sensitivity and 67.3% specificity for recognizing CAD, and 53.0% sensitivity and 80.3% specificity for recognizing severe coronary artery lesions.

CONCLUSION

The activity of LP-PLA2 is positively correlated to the seriousness of CAD.

Lipoprotein(a) and calcific aortic valve stenosis: A systematic review

Calcific aortic valve stenosis (AS) is the most common form of acquired valvular heart disease needing intervention and our understanding of this disease has evolved from one of degenerative calcification to that of an active process driven by the interplay of genetic factors and chronic inflammation modulated by risk factors such as smoking, hypertension and elevated cholesterol. Lipoprotein(a) [Lp (a)] is a cholesterol rich particle secreted by the liver which functions as the major lipoprotein carrier of phosphocholine-containing oxidized phospholipids. Lp(a) levels are largely genetically determined by polymorphisms in the LPA gene. While there is an extensive body of evidence linking Lp(a) to atherosclerotic cardiovascular disease, emerging evidence now suggests a similar association of Lp(a) to calcific AS. In this article, we performed a systematic review of all published literature to assess the association between Lp(a) and calcific aortic valve (AV) disease. In addition, we review the potential mechanisms by which Lp(a) influences the progression of valve disease. Our review identified a total of 21 studies, varying from case-control studies, prospective or retrospective observational cohort studies to Mendelian randomized studies that assessed the association between Lp(a) and calcific AS. All but one of the above studies demonstrated significant association between elevated Lp(a) and calcific AS. We conclude that there is convincing evidence supporting a causal association between elevated Lp(a) and calcific AS. In addition, elevated Lp(a) predicts a faster hemodynamic progression of AS, and increased risk of AV replacement, especially in younger patients. Further research into the clinical utility of Lp(a) as a marker for predicting the incidence, progression, and outcomes of sclerodegenerative AV disease is needed.

Relationship of lipoprotein-associated phospholipase A2(Lp-PLA2) and periprocedural myocardial injury in patients undergoing elective percutaneous coronary intervention

BACKGROUND

Percutaneous coronary intervention (PCI) is one of the dominant methods for revascularization in patients with coronary heart disease (CHD). However, periprocedural myocardial injury (PMI) is a frequent complication following PCI and is known to be a predictor of postprocedural cardiovascular morbidity and mortality. Although several studies try to identify serum markers to predict the PMI, there is a little information about the role of lipoprotein-associated phospholipase A2 (Lp-PLA2) as a predictor of PMI. Therefore, we aimed to investigate the relationship of Lp-PLA2 levels and PMI in patients undergoing elective PCI.

METHODS

This study included 265 consecutive patients with normal preprocedural cardiac troponin T(cTNT) who received elective PCI. The samples for cTNT were collected at 8, 16, and 24 h after PCI to assess perioperative myocardial injury. The Lp-PLA2 and other serum lipid parameters were measured after 12 fasting hours before PCI.

RESULTS

The data suggested that the patients with preprocedural high Lp-PLA2 were strongly and independently correlated with the risk of PMI. Pearson correlation analysis showed that preprocedural Lp-PLA2 was significantly positively correlated with postprocedural cTnT elevation (r = 0.694, p < 0.05). Binary logistic regression analysis was used to analyze the risk factors of PMI, we found that Lp-PLA2 was independent risk factor for postprocedural cTnT elevation. The area under Receiver Operating Characteristic curve of Lp-PLA2 was 0.757 (95%CI 0.692 ~ 0.821, p < 0.001), the best cut-off point was 185 ng/ml, sensitivity and specificity were 65.33% and 76.32%.

CONCLUSION

Our study demonstrated that preprocedural Lp-PLA2 was associated with postprocedural cTnT elevation and was the independent risk factor of PMI.

Forty Years Since the Structural Elucidation of Platelet-Activating Factor (PAF): Historical, Current, and Future Research Perspectives

In the late 1960s, Barbaro and Zvaifler described a substance that caused antigen induced histamine release from rabbit platelets producing antibodies in passive cutaneous anaphylaxis. Henson described a ‘soluble factor’ released from leukocytes that induced vasoactive amine release in platelets. Later observations by Siraganuan and Osler observed the existence of a diluted substance that had the capacity to cause platelet activation. In 1972, the term platelet-activating factor (PAF) was coined by Benveniste, Henson, and Cochrane. The structure of PAF was later elucidated by Demopoulos, Pinckard, and Hanahan in 1979. These studies introduced the research world to PAF, which is now recognised as a potent phospholipid mediator. Since its introduction to the literature, research on PAF has grown due to interest in its vital cell signalling functions and more sinisterly its role as a pro-inflammatory molecule in several chronic diseases including cardiovascular disease and cancer. As it is forty years since the structural elucidation of PAF, the aim of this review is to provide a historical account of the discovery of PAF and to provide a general overview of current and future perspectives on PAF research in physiology and pathophysiology.

Lp-PLA2 Selective Inhibitor (Darapladib) Effect In Lowering The Expression Level Of IL-1B And IL-6 In The Renal At Type 2 Diabetes Mellitus

PURPOSE

The aim of this study is to prove that type 2 diabetes mellitus can induce increasing inflammation marker in renal and that the provision of darapladib as Lp-LA2 Inhibitor agents can inhibit inflammation that were measured from the expression of IL-1B and IL-6- type cytokine in renal. This study also discusses the correlation between IL-1B and IL-6- type cytokine expression in renal.

METHODS

Thirty Sprague-Dawley (SD) rats were divided into three main groups; those are negative control group (NC), Type 2 Diabetes Mellitus group (T2DM) given high fat diet (HFD) with streptozotocin intraperitoneal injection (35mg/kg BW) and diabetes mellitus + darapladib group (DM + DP). Each group was treated within two serial treatment time: 8 weeks and 16 weeks. Expressions of IL-1B and IL-6- type cytokine in renal were the markers that we measured by immunofluorosense method.

RESULTS

The administration of darapladib can significantly decrease the expression of IL-1B- type cytokine (p ANOVA = 0.029, p < 0.005) measured in rats' renal both at weeks 8 and 16 in the T2DM group. The Expression of IL-6- type cytokine also showed a significant difference after treated with darapladib both at weeks 8 and 16 in T2DM group with p-value of ANOVA = 0.033, p < 0.005. The Pearson correlation showed a strong correlation (linear regression value was r2 = 0.743).

CONCLUSION

Our results show that atherosclerosis caused by inflammation in renal T2DM SD rats could be inhibited by the administration of darapladib.

Pharmacokinetics and exploratory efficacy biomarkers of bococizumab, an anti-PCSK9 monoclonal antibody, in hypercholesterolemic Japanese subjects

Objective: Bococizumab, a monoclonal antibody targeting proprotein convertase subtilisin/kexin type 9, has been shown to reduce low-density lipoprotein cholesterol (LDL-C). Here, we describe the pharmacokinetics and pharmacodynamics of bococizumab and its effect on lipoprotein particle composition and other biomarkers, based on a double-blind, placebo-controlled, randomized, dose-ranging study. Materials and methods: The study consisted of two populations: Japanese subjects with uncontrolled LDL-C (LDL-C ≥ 100 mg/dL) despite treatment with atorvastatin (n = 121) and Japanese subjects naïve to lipid-lowering agents with LDL-C ≥ 130 mg/dL (n = 97). Subjects were randomized to receive either bococizumab 50, 100, or 150 mg or placebo, every 2 weeks. One arm of subjects in the atorvastatin-treated population received ezetimibe 10 mg instead of bococizumab. Results: In both populations, bococizumab exposure increased with increasing dose, and subjects with lower body weights tended to have higher exposures. Bococizumab treatment was associated with a dose-dependent reduction in LDL particles and a small increase in total high-density lipoprotein (HDL) particles. Significant reductions in lipoprotein-associated phospholipase A2 (Lp-PLA2) were observed for bococizumab-treated subjects but not for subjects treated with placebo or ezetimibe. Conclusion: Increased bococizumab dosage resulted in increased exposure. Levels of LDL and HDL particles and biomarkers such as Lp-PLA2 were also altered with bococizumab treatment. (ClinicalTrials.gov identifier: NCT02055976).

Metabolomics study on the therapeutic effect of traditional Chinese medicine Xue-Fu-Zhu-Yu decoction in coronary heart disease based on LC-Q-TOF/MS and GC-MS analysis

The present study aims is to investigate the metabolic mechanism of Xue-Fu-Zhu-Yu decoction (XFZYD) in the treatment of blood-stasis syndrome in Coronary Heart Disease (CHD). To that end, 30 CHD patients with Blood-Stasis Syndrome (BSS) and 20 healthy subjects were enrolled. LC-Q-TOF/MS analysis determined that in comparison between CHD with BSS patients (Group A) and healthy subjects (Group C), 59 significantly differential metabolites in the positive mode and 18 significantly differential metabolites in the negative mode. The metabolite constituents in the plasma of 30 CHD with BSS patients before (group A) and after 30 days of treatment (Group B), and 20 healthy subjects (Group C) were analyzed using LC-Q-TOF/MS and GC-MS. Based on multivariate statistical analysis (PCA, PLS-DA and OPLS-DA), we determined 69 differential metabolites. The levels of hemorheology indexes were significantly down-regulated after treatment. Metabolic pathway attribution analysis showed that lipid metabolism, amino acid metabolism and bile acid metabolism pathways are involved. Our study identifies the metabolic networks of CHD and demonstrates the efficacy of this metabolomics approach to systematically study the therapeutic effect of XFZYC on CHD.

Effects of Extended-Release Niacin on Quartile Lp-PLA2 Levels and Clinical Outcomes in Statin-treated Patients with Established Cardiovascular Disease and Low Baseline Levels of HDL-Cholesterol: Post Hoc Analysis of the AIM HIGH Trial

Background:

Lipoprotein-associated phospholipase A2 (LpPLA2) is an inflammatory marker that has been associated with the presence of vulnerable plaque and increased risk of cardiovascular (CV) events.

Objective:

To assess the effect of extended-release niacin (ERN) on Lp-PLA2 activity and clinical outcomes.

Methods:

We performed a post hoc analysis in 3196 AIM-HIGH patients with established CV disease and low baseline levels of high-density lipoprotein cholesterol (HDL-C) who were randomized to ERN versus placebo on a background of simvastatin therapy (with or without ezetimibe) to assess the association between baseline Lp-PLA2 activity and the rate of the composite primary end point (CV death, myocardial infarction, stroke, hospitalization for unstable angina, and symptom-driven revascularization).

Results:

Participants randomized to ERN, but not those randomized to placebo, experienced a significant 8.9% decrease in LpPLA2. In univariate analysis, the highest quartile of LpPLA2 activity (>208 nmol/min/mL, Q4) was associated with higher event rates compared to the lower quartiles in the placebo group (log rank P = .032), but not in the ERN treated participants (log rank P = .718). However, in multivariate analysis, adjusting for sex, diabetes, baseline LDL-C, HDL-C, and triglycerides, there was no significant difference in outcomes between the highest Lp-PLA2 activity quartile versus the lower quartiles in both the placebo and the ERN groups.

Conclusion:

Among participants with stable CV disease on optimal medical therapy, elevated Lp-PLA2 was associated with higher CV events; however, addition of ERN mitigates this effect. This association in the placebo group was attenuated after multivariable adjustment, which suggests that Lp-PLA2 does not improve risk assessment beyond traditional risk factors.

Current concepts in atherosclerosis

Atherosclerosis is a complex disease process. It is increasingly recognised that both lipoprotein retention and inflammatory cellular components are intricately related in the initiation and development of atherosclerotic plaque. LDL-c (cholesterol) has been long established as a cause for atherosclerosis; additionally, inflammatory cells such as monocytes and subsequently foam cells have also been directly linked to the progression of atherosclerotic disease. Emerging data suggest that structures outside vascular intima and media are also closely related to atherosclerosis. Perivascular adipose tissue (PVAT) may be a determinant of the inflammatory status of the atherosclerotic plaque. All these features are becoming extremely relevant as therapies against atherosclerosis are targeting both lipid retention and inflammation. Recently, there has been some success in these novel therapies, such as the proprotein convertase subtilisin-kexin type 9 (PCSK-9) inhibitor evolocumab and the interleukin-1ß neutralising antibody, canakinumab, in reducing cardiovascular events when added to standard therapy such as statin. This review will discuss the pathogenesis of atherosclerosis, including some novel features, and its management using new anti-atherosclerotic drugs.

Mining the potential therapeutic targets for coronary artery disease by bioinformatics analysis

The present study aimed to mine therapeutic molecular targets that play an important part in the progression of coronary artery disease (CAD). The gene expression profile GSE28829 dataset and the microRNA (miRNA) expression profile GSE59421 dataset were downloaded from the Gene Expression Omnibus (GEO) database. The GEO2R online analytical tool was used to identify differentially expressed genes (DEGs) and miRNAs (DEMs). The target genes of DEMs were identified using the miRWalk2.0 web-based tool and 2 miRNA-gene regulatory networks were constructed using Cytoscape software. Subsequently, enriched Gene Ontology (GO) terms of miRNA-target DEGs were obtained using the Database for Visualization, Annotation and Integrated Analysis, and locations of these genes in the chromosomes were determined by Map Viewer. In the present study, 350 DEGs and 66 DEMs were screened. A total of 3,588 target genes were identified from the DEMs, and 57 of these target genes and established DEGs were identified to overlap. GO terms associated with 5 processes, and 4 types of composition were identified to be enriched in the miRNA-target DEGs. Furthermore, 26 miRNA-gene regulatory pairs were obtained between the 57 target genes and DEMs. The 26 miRNA-target DEGs were unevenly distributed, and no genes were located on the sex chromosomes. As a result of the present study, potential therapeutic targets for CAD were identified through bioinformatics analysis.

Chronic inhibition of lipoprotein-associated phospholipase A2 does not improve coronary endothelial function: A prospective, randomized-controlled trial

AIMS

Lipoprotein-associated phospholipase A₂ (Lp-PLA₂), a novel biomarker for vascular inflammation, is associated with coronary endothelial dysfunction (CED) and independently predicts cardiovascular events. The current study aimed to determine whether darapladib, an orally administered Lp-PLA₂ inhibitor, improved CED.

METHODS AND RESULTS

Fifty-four patients with CED were enrolled in a double-blinded randomized placebo-controlled trial, and were randomized to receive oral darapladib, 160mg daily, or placebo. Coronary angiography and invasive coronary endothelial function assessment were performed at baseline and post-6months of treatment. Primary endpoints were change in coronary artery diameter and coronary blood flow in response to acetylcholine. Additionally, Lp-PLA₂ activity was measured at baseline and on follow-up to evaluate for adherence and drug effect. Fifty-four patients were randomized to placebo (n=29) and darapladib (n=25). Mean age in darapladib group was 55.2.±11.7years vs. 54.0±10.5years (p=0.11). On follow-up, there was no significant difference in the percent response to acetylcholine of coronary artery diameter in treatment vs. placebo group (+3 (IQR -9, 15) vs. +3 (-12, 19); p=0.87) or coronary blood flow (-5 (IQR -24, 54) vs. 39 (IQR -26, 67); p=0.41). There was significant reduction in Lp-PLA₂ activity in the treatment arm vs. placebo (-76 (IQR -113, -52) vs. -7(-21, -7); p<0.001).

DISCUSSION

Lp-PLA₂ inhibition with darapladib did not improve coronary endothelial function, despite significantly reduced Lp-PLA2 activity with darapladib. This study suggests endogenous Lp-PLA₂ may not play a primary role in coronary endothelial function in humans. CLINICALTRIALS.

GOV IDENTIFIER

NCT01067339.

Inflammation: A Novel Therapeutic Target/Direction in Atherosclerosis

Over the past two decades, the viewpoint of atherosclerosis has been replaced gradually by a lipid-driven, chronic, low-grade inflammatory disease of the arterial wall. Current treatment of atherosclerosis is focused on limiting its risk factors, such as hyperlipidemia or hypertension. However, treatment targeting the inflammatory nature of atherosclerosis is still very limited and deserves further attention to fight atherosclerosis successfully. Here, we review the current development of inflammation and atherosclerosis to discuss novel insights and potential targets in atherosclerosis, and to address drug discovery based on anti-inflammatory strategy in atherosclerotic disease.

Potential of anti-inflammatory agents for treatment of atherosclerosis

Chronic inflammation is a central pathogenic mechanism of atherosclerosis induction and progression. Vascular inflammation is associated with accelerated onset of late atherosclerosis complications. Atherosclerosis-related inflammation is mediated by a complex cocktail of pro-inflammatory cytokines, chemokines, bioactive lipids, and adhesion molecules, and blocking the key pro-atherogenic inflammatory mechanisms can be beneficial for treatment of atherosclerosis. Therapeutic agents that specifically target some of the atherosclerosis-related inflammatory mechanisms have been evaluated in preclinical and clinical studies. The most promising anti-inflammatory compounds for treatment of atherosclerosis include non-specific anti-inflammatory drugs, phospholipase inhibitors, blockers of major inflammatory cytokines, leukotrienes, adhesion molecules, and pro-inflammatory signaling pathways, such as CCL2-CCR2 axis or p38 MAPK pathway. Ongoing studies attempt evaluating therapeutic utility of these anti-inflammatory drugs for treatment of atherosclerosis. The obtained results are important for our understanding of atherosclerosis-related inflammatory mechanisms and for designing randomized controlled studies assessing the effect of specific anti-inflammatory strategies on cardiovascular outcomes.

Oxidized phospholipids and lipoprotein-associated phospholipase A2 as important determinants of Lp(a) functionality and pathophysiological role

Lipoprotein(a) [Lp(a)] is composed of a low density lipoprotein (LDL)-like particle to which apolipoprotein (a) [apo(a)] is linked by a single disulfide bridge. Lp(a) is considered a causal risk factor for ischemic cardiovascular disease (CVD) and calcific aortic valve stenosis (CAVS). The evidence for a causal role of Lp(a) in CVD and CAVS is based on data from large epidemiological databases, mendelian randomization studies, and genome-wide association studies. Despite the well-established role of Lp(a) as a causal risk factor for CVD and CAVS, the underlying mechanisms are not well understood. A key role in the Lp(a) functionality may be played by its oxidized phospholipids (OxPL) content. Importantly, most of circulating OxPL are associated with Lp(a); however, the underlying mechanisms leading to this preferential sequestration of OxPL on Lp(a) over the other lipoproteins, are mostly unknown. Several studies support the hypothesis that the risk of Lp(a) is primarily driven by its OxPL content. An important role in Lp(a) functionality may be played by the lipoprotein-associated phospholipase A₂ (Lp-PLA₂), an enzyme that catalyzes the degradation of OxPL and is bound to plasma lipoproteins including Lp(a). The present review article discusses new data on the pathophysiological role of Lp(a) and particularly focuses on the functional role of OxPL and Lp-PLA₂ associated with Lp(a).

The effect of Danshen extract on lipoprotein-associated phospholipase A2 levels in patients with stable angina pectoris: study protocol for a randomized controlled trial - the DOLPHIN study

Background

Lipoprotein-associated phospholipase A₂ (Lp-PLA₂), a biomarker of oxidation and inflammation, has been associated with increased coronary artery disease risk. To date, very few studies have examined the Chinese herbal drug Danshen or its extract on Lp-PLA₂ in patients with stable angina pectoris. In this study, we aim to investigate the effect of Danshen extract on Lp-PLA₂ level in patients with stable angina.

Methods/design

This is a randomized, single-blind, placebo-controlled, adaptive clinical trial. A total of 156 patients meeting the eligibility criteria will be randomly assigned to either the Danshen extract (DanshenDuofensuanyan injection and Danshen drop spill) group or the placebo group in a 1:1 ratio. Participants will then undergo treatment with DanshenDuofensuanyan injection or placebo (glucose) during hospitalization, followed by open-label Danshen drop spill (30 pills/day) in Danshen extract group for 60 days after discharge. Because this is an adaptive trial, two interim analyses are prospectively planned. These will be performed after one-third and two-thirds of the patients, respectively, have completed the trial. On the basis of the results of these interim analyses, a data monitoring committee will determine how to modify aspects of the study without undermining the validity and integrity of the trial. The primary outcome measure is the serum level of Lp-PLA₂ in the Danshen extract group and the placebo group. The secondary outcomes include the proportion of patients who show a clinically significant change, which is defined as at least a 20-point improvement in angina frequency score on the Seattle Angina Questionnaire and the carotid intima-media thickness, which will be measured using ultrasound. Other secondary efficacy and safety outcomes will also be assessed.

Discussion

This study will provide evidence that Danshen extract is beneficial for stable angina and may establish a possible mechanism of Danshen treatment effects on cardiovascular disease. This study may also validate an objective blood test (LP-PLA₂ level) for assessing the effectiveness of Danshen therapy in patients with stable angina pectoris.

Trial registration

ClinicalTrials.gov, NCT02870764. Registered on 13 August 2016.

Electronic supplementary material

The online version of this article (doi:10.1186/s13063-017-2336-2) contains supplementary material, which is available to authorized users.

Targeting inflammation to reduce cardiovascular disease risk: a realistic clinical prospect?

Data from basic science experiments is overwhelmingly supportive of the causal role of immune-inflammatory response(s) at the core of atherosclerosis, and therefore, the theoretical potential to manipulate the inflammatory response to prevent cardiovascular events. However, extrapolation to humans requires care and we still lack definitive evidence to show that interfering in immune-inflammatory processes may safely lessen clinical atherosclerosis. In this review, we discuss key therapeutic targets in the treatment of vascular inflammation, placing basic research in a wider clinical perspective, as well as identifying outstanding questions.

LINKED ARTICLES

This article is part of a themed section on Targeting Inflammation to Reduce Cardiovascular Disease Risk. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.22/issuetoc and http://onlinelibrary.wiley.com/doi/10.1111/bcp.v82.4/issuetoc.

Impact of 8-week linoleic acid intake in soy oil on Lp-PLA2 activity in healthy adults

BACKGROUND

No intervention follow-up study has examined the association between plasma n-6 polyunsaturated fatty acids (PUFAs) and lipoprotein-associated phospholipase A₂ (Lp-PLA₂), which is a risk factor for cardiovascular disease (CVD). We aimed to determine whether the administration of linoleic acid (LA, 18:2n-6) in soy oil affected Lp-PLA₂ activity in healthy adults.

METHODS

Self-reported healthy participants (n = 150) were randomly assigned to three groups: a low LA group, in which 10 mL soy oil was replaced with one apple; a medium LA group, in which the typical food intake was maintained; and a high LA group, in which 1/3 cup of cooked refined rice was replaced with 9.9 g of soy oil capsules daily. Plasma fatty acids and Lp-PLA₂ activity were measured along with other CVD risk factors.

RESULTS

After 8 weeks of treatment, plasma LA levels decreased in the low LA group and increased in the high LA group. The high LA group showed greater increases in apolipoprotein B (apoB) and oxidized low-density lipoprotein (ox-LDL) than those in the low LA group. Plasma LA levels and Lp-PLA₂ activities demonstrated greater increases in the high LA group than those in the medium and low LA groups. Changes in plasma LA positively and independently correlated with changes in Lp-PLA₂ activity, which was negatively correlated with changes in collagen-epinephrine closure time (CEPI-CT).

CONCLUSIONS

An increase in plasma LA following intake of soy oil was independently associated with Lp-PLA₂ activity, which was also related to apoB, ox-LDL and CEPI-CT.

TRIAL REGISTRATION

ClinicalTrail.gov Identifier: NCT02753907, registered 25 April 2016 (retrospectively registered).

Genetic invalidation of Lp-PLA2 as a therapeutic target: Large-scale study of five functional Lp-PLA2-lowering alleles

Aims Darapladib, a potent inhibitor of lipoprotein-associated phospholipase A2 (Lp-PLA2), has not reduced risk of cardiovascular disease outcomes in recent randomized trials. We aimed to test whether Lp-PLA2 enzyme activity is causally relevant to coronary heart disease. Methods In 72,657 patients with coronary heart disease and 110,218 controls in 23 epidemiological studies, we genotyped five functional variants: four rare loss-of-function mutations (c.109+2T > C (rs142974898), Arg82His (rs144983904), Val279Phe (rs76863441), Gln287Ter (rs140020965)) and one common modest-impact variant (Val379Ala (rs1051931)) in PLA2G7, the gene encoding Lp-PLA2. We supplemented de-novo genotyping with information on a further 45,823 coronary heart disease patients and 88,680 controls in publicly available databases and other previous studies. We conducted a systematic review of randomized trials to compare effects of darapladib treatment on soluble Lp-PLA2 activity, conventional cardiovascular risk factors, and coronary heart disease risk with corresponding effects of Lp-PLA2-lowering alleles. Results Lp-PLA2 activity was decreased by 64% ( p = 2.4 × 10-25) with carriage of any of the four loss-of-function variants, by 45% ( p < 10-300) for every allele inherited at Val279Phe, and by 2.7% ( p = 1.9 × 10-12) for every allele inherited at Val379Ala. Darapladib 160 mg once-daily reduced Lp-PLA2 activity by 65% ( p < 10-300). Causal risk ratios for coronary heart disease per 65% lower Lp-PLA2 activity were: 0.95 (0.88-1.03) with Val279Phe; 0.92 (0.74-1.16) with carriage of any loss-of-function variant; 1.01 (0.68-1.51) with Val379Ala; and 0.95 (0.89-1.02) with darapladib treatment. Conclusions In a large-scale human genetic study, none of a series of Lp-PLA2-lowering alleles was related to coronary heart disease risk, suggesting that Lp-PLA2 is unlikely to be a causal risk factor.

Lipoprotein-Associated Phospholipase A2 Activity Is a Marker of Risk But Not a Useful Target for Treatment in Patients With Stable Coronary Heart Disease

BACKGROUND

We evaluated lipoprotein-associated phospholipase A2 (Lp-PLA2) activity in patients with stable coronary heart disease before and during treatment with darapladib, a selective Lp-PLA2 inhibitor, in relation to outcomes and the effects of darapladib in the STABILITY trial.

METHODS AND RESULTS

Plasma Lp-PLA2 activity was determined at baseline (n=14 500); at 1 month (n=13 709); serially (n=100) at 3, 6, and 18 months; and at the end of treatment. Adjusted Cox regression models evaluated associations between Lp-PLA2 activity levels and outcomes. At baseline, the median Lp-PLA2 level was 172.4 μmol/min per liter (interquartile range 143.1-204.2 μmol/min per liter). Comparing the highest and lowest Lp-PLA2 quartile groups, the hazard ratios were 1.50 (95% CI 1.23-1.82) for the primary composite end point (cardiovascular death, myocardial infarction, or stroke), 1.95 (95% CI 1.29-2.93) for hospitalization for heart failure, 1.42 (1.07-1.89) for cardiovascular death, and 1.37 (1.03-1.81) for myocardial infarction after adjustment for baseline characteristics, standard laboratory variables, and other prognostic biomarkers. Treatment with darapladib led to a ≈65% persistent reduction in median Lp-PLA2 activity. There were no associations between on-treatment Lp-PLA2 activity or changes of Lp-PLA2 activity and outcomes, and there were no significant interactions between baseline and on-treatment Lp-PLA2 activity or changes in Lp-PLA2 activity levels and the effects of darapladib on outcomes.

CONCLUSIONS

Although high Lp-PLA2 activity was associated with increased risk of cardiovascular events, pharmacological lowering of Lp-PLA2 activity by ≈65% did not significantly reduce cardiovascular events in patients with stable coronary heart disease, regardless of the baseline level or the magnitude of change of Lp-PLA2 activity.

CLINICAL TRIAL REGISTRATION

URL: https://www.clinicaltrials.gov. Unique identifier: NCT00799903.

Immune-mediated mechanisms of atherosclerosis and implications for the clinic

INTRODUCTION

A large body of evidence supports the inflammatory hypothesis of atherosclerosis, and both innate and adaptive immune responses play important roles in all disease stages. Areas covered: Here, we review our understanding of the role of the immune response in atherosclerosis, focusing on the pathways currently amenable to therapeutic modulation. We also discuss the advantages or undesirable effects that may be foreseen from targeting the immune response in patients at high cardiovascular risk, suggesting new avenues for research. Expert commentary: There is an extraordinary opportunity to directly test the inflammatory hypothesis of atherosclerosis in the clinic using currently available therapeutics. However, a more balanced interpretation of the experimental and translational data is needed, which may help address and identify in more detail the appropriate settings where an immune pathway can be targeted with minimal risk.

A phenome-wide association study of a lipoprotein-associated phospholipase A2 loss-of-function variant in 90 000 Chinese adults

Background: Lipoprotein-associated phospholipase A₂ (Lp-PLA₂) has been implicated in development of atherosclerosis; however, recent randomized trials of Lp-PLA₂ inhibition reported no beneficial effects on vascular diseases. In East Asians, a loss-of-function variant in the PLA2G7 gene can be used to assess the effects of genetically determined lower Lp-PLA₂.

Methods:PLA2G7 V279F (rs76863441) was genotyped in 91 428 individuals randomly selected from the China Kadoorie Biobank of 0.5 M participants recruited in 2004–08 from 10 regions of China, with 7 years’ follow-up. Linear regression was used to assess effects of V279F on baseline traits. Logistic regression was conducted for a range of vascular and non-vascular diseases, including 41 ICD-10 coded disease categories.

Results:PLA2G7 V279F frequency was 5% overall (range 3–7% by region), and 9691 (11%) participants had at least one loss-of-function variant. V279F was not associated with baseline blood pressure, adiposity, blood glucose or lung function. V279F was not associated with major vascular events [7141 events; odds ratio (OR) = 0.98 per F variant, 95% confidence interval (CI) 0.90-1.06] or other vascular outcomes, including major coronary events (922 events; 0.96, 0.79-1.18) and stroke (5967 events; 1.00, 0.92-1.09). Individuals with V279F had lower risks of diabetes (7031 events; 0.91, 0.84-0.98) and asthma (182 events; 0.53, 0.28-0.98), but there was no association after adjustment for multiple testing.

Conclusions: Lifelong lower Lp-PLA₂ activity was not associated with major risks of vascular or non-vascular diseases in Chinese adults. Using functional genetic variants in large-scale prospective studies with linkage to a range of health outcomes is a valuable approach to inform drug development and repositioning.

New and emerging biomarkers in cardiovascular disease

Cardiovascular disease (CVD) is the most common cause of death and disability worldwide. Therefore, great importance has been placed on the discovery of novel risk factors and metabolic pathways relevant in the prevention and management of CVD. Such research is ongoing and may continue to lead to better risk stratification of individuals and/or the development of new intervention targets and treatment options. This review highlights emerging biomarkers related to lipid metabolism, glycemia, inflammation, and cardiac damage, some of which show promising associations with CVD risk and provide further understanding of the underlying pathophysiology. However, their measurement methodology and assays will require validation and standardization, and it will take time to accumulate evidence of their role in CVD in various population settings in order to fully assess their clinical utility. Several of the novel biomarkers represent intriguing, potentially game-changing targets for therapy.

The role of inflammatory biomarkers in developing targeted cardiovascular therapies: lessons from the cardiovascular inflammation reduction trials

Anti-inflammatory add-on therapy to conventional cardiovascular prophylaxis has been proposed as a novel therapeutic approach to potentially reduce residual cardiovascular risk. This hypothesis has been challenged by a series of unsuccessful Phase III studies testing the impact on clinical outcomes of novel agents with immunomodulatory actions. Specifically, the apparent ability of phospholipase A2 (PLA2) inhibitors and of antioxidants to ameliorate inflammation and to reduce coronary disease in Phase II trials did not translate into improved secondary cardiovascular prevention in larger population-based studies. Other anti-inflammatory agents are still under scrutiny. However, studies to date have lacked information on the inflammatory profile of the participants, both at baseline and at follow-up, thereby limiting the possibility of identifying subgroups of patients in whom 'residual inflammation' can be detected despite optimal conventional therapy, and who could therefore benefit from a cardiovascular prevention strategy specifically targeting inflammation. This has also rendered it difficult to interpret the results as a conclusive demonstration of inefficacy of the tested anti-inflammatory strategies in the treatment of atherosclerosis. We here discuss the importance of better patient characterization to minimize heterogeneity of the study population, so that effectiveness of different anti-inflammatory strategies can be evaluated in targeted subgroups of patients. We also illustrate how specific inflammatory biomarkers could assist in this process, with particular emphasis on the roles of high-sensitivity C-reactive protein and circulating monocyte phenotype.

Darapladib for the treatment of cardiovascular disease

Elevated levels of phospholipase A2 have been linked to atherosclerotic plaque progression, instability via promoting inflammation and subsequent acute coronary events. Epidemiological studies have demonstrated the correlation between elevated levels associated phospholipase A2 and cardiovascular events. Therefore, specific inhibition of lipoprotein-associated phospholipase A2 with darapladib has been tested as a therapeutic option for atherosclerosis. The aim of this profile is to review the physiologic aspects of lipoprotein-associated phospholipase A2 and to revisit the clinical evidence of darapladib as therapeutic option for atherosclerosis.

The pharmacokinetics and safety of darapladib in subjects with severe renal impairment

AIM

Darapladib is a potent and reversible orally active inhibitor of lipoprotein-associated phospholipase A2 (Lp-PLA2 ). The aim of the study was to assess the effects of severe renal impairment on the pharmacokinetics and safety/tolerability of darapladib compared with normal renal function.

METHODS

This was an open label, parallel group study of darapladib following 10 day once daily 160 mg oral dosing in subjects with normal (n = 8) and severe renal impairment (estimated glomerular filtration rate <30 ml min(-1) 1.73 m(-2) , n = 8). Plasma concentrations of total and unbound darapladib as well as total darapladib metabolites were determined in samples obtained over 24 h on day 10.

RESULTS

Plasma concentrations of total and unbound darapladib as well as all three metabolites were higher in subjects with severe renal impairment. Area under the plasma concentration vs. time curve between time zero and 24 h (AUC(0,24 h) and maximum plasma concentration (Cmax ) of total darapladib in severely renally impaired subjects were 52% and 59% higher than those in the matched healthy subjects, respectively. Similar results were found with the darapladib metabolites. Darapladib was highly plasma protein bound with 0.047% and 0.034% unbound circulating in plasma in severely renally impaired and healthy subjects, respectively. Unbound plasma darapladib exposures were more than two-fold higher in severely renally impaired subjects than in healthy controls. Adverse events (AE) were reported in 38% of healthy subjects and 75% of severely renally impaired subjects, most of which were mild or moderate in intensity.

CONCLUSIONS

The results of this study showed that darapladib exposure was increased in subjects with severe renal impairment compared with healthy controls. However, darapladib was generally well tolerated in both groups.