Lp-PLA2 Inhibitors for the Reduction of Cardiovascular Events

Associations between healthy food groups and platelet-activating factor, lipoprotein-associated phospholipase A2 and C-reactive protein: a cross-sectional study

PURPOSE

To investigate the association between pro-inflammatory markers platelet-activating factor (PAF), lipoprotein-associated phospholipase A2 (Lp-PLA2), hsCRP, and intake of core food groups including fruit, cruciferous and other vegetables, grains, meat and poultry, fish and seafood, nuts and legumes, and dairy.

METHODS

A cross-sectional study was conducted. 100 adults (49 ± 13 years, 31% male) with variable cardiovascular disease risk were recruited. Data were collected in 2021 and 2022. Fasting PAF, Lp-PLA2 activity, hsCRP and usual dietary intake (via a validated food frequency questionnaire) were measured. Intake of foods were converted into serves and classified into food groups. Correlations and multiple regressions were performed with adjustment for confounders.

RESULTS

A one-serve increase in cruciferous vegetables per day was associated with 20-24% lower PAF levels. An increase of one serve per day of nuts and legumes was associated with 40% lower hsCRP levels. There were small correlations with PAF and Lp-PLA2 and cheese, however, these were not significant at the Bonferroni-adjusted P < 0.005 level.

CONCLUSION

The lack of associations between PAF and Lp-PLA2 and other healthy foods may be due to confounding by COVID-19 infection and vaccination programs which prevents any firm conclusion on the relationship between PAF, Lp-PLA2 and food groups. Future research should aim to examine the relationship with these novel markers and healthy food groups in a non-pandemic setting.

Interrelationships among platelet-activating factor and lipoprotein-associated phospholipase A2 activity and traditional cardiovascular risk factors

Traditionally cardiovascular disease (CVD) risk has been assessed through blood lipids and inflammatory marker C-reactive protein (hsCRP). Recent clinical interest in novel pro-inflammatory markers platelet-activating factor (PAF) and lipoprotein-associated phospholipase A₂ (Lp-PLA₂ ) recognizes that vascular damage can exist in the absence of traditional risk factors. This cross-sectional study investigated the potential relationship between circulating PAF, Lp-PLA₂ , hsCRP, and traditional risk factors for CVD. One hundred adults (49 ± 13 years, 31% male) with variable CVD risk were recruited. Fasting inflammatory markers PAF, Lp-PLA₂ and hsCRP and total, high-density lipoprotein (HDL), low-density lipoprotein (LDL) cholesterol, and triglycerides were measured. Blood pressure, body mass index, and waist circumference were measured. Medical and physical activity data were self-reported. Linear and multiple regressions were performed. PAF, Lp-PLA₂ , and hsCRP independently correlated with several CVD risk factors. PAF was correlated significantly with risk factors in an unexpected way; there was a medium positive correlation between PAF and HDL cholesterol (r = 0.394, p < 0.001) and medium negative correlations with Total:HDL cholesterol; (r = -0.436, p < 0.001) systolic blood pressure; (r = -0.307, p = 0.001); BMI (r = -0.381, p < 0.001); and waist circumference (r = -0.404, p < 0.001). There were large positive correlations between Lp-PLA₂ and LDL (r = 0.525, p < 0.001) and non-HDL cholesterol (r = 0.508, p < 0.001). There were large positive correlations between hsCRP and Total:HDL cholesterol (r = 0.524, p < 0.001); BMI (r = 0.668, p < 0.001); and waist circumference (r = 0.676, p < 0.001). PAF, Lp-PLA₂ , and hsCRP are implicated in the pathophysiology of inflammation in CVD; however, the relationships between each marker and traditional risk factors were different suggesting they may be involved in different atherogenic pathways.

The association between dietary patterns and the novel inflammatory markers platelet-activating factor and lipoprotein-associated phospholipase A2: a systematic review

CONTEXT

Atherosclerosis is a disease of chronic inflammation. Recent research has identified 2 novel inflammatory biomarkers: platelet-activating factor (PAF) and lipoprotein-associated phospholipase A2 (Lp-PLA2). Diet has been proposed as a mediator of inflammation, but to date, the focus for these novel biomarkers has been on individual foods and nutrients rather than overall dietary patterns.

OBJECTIVE

To systematically review the literature on the association between dietary patterns and PAF and Lp-PLA2.

DATA SOURCES

The PubMed, Embase, CINAHL, and Cochrane CENTRAL literature databases were searched.

DATA ANALYSIS

Study quality was evaluated using the Quality Criteria Checklist. Sixteen studies (n = 4 observational and n = 12 interventional) were included and assessed for associations between dietary patterns and PAF and Lp-PLA2.

CONCLUSION

Study quality varied from neutral (n = 10) to positive (n = 6). Mediterranean, heart healthy, and vegetarian dietary patterns were associated with improved levels of PAF and Lp-PLA2. Conversely, Western dietary patterns were less favorable. A range of well-established, healthier dietary patterns may lower inflammation and the risk of atherosclerosis. More well-designed studies are needed to confirm these findings and identify other dietary patterns that improve inflammation.

Predictive Value of Perioperative Cytokine Levels on the Risk for In-Stent Restenosis in Acute Myocardial Infarction Patients

To investigate the value of perioperative cytokine levels in predicting the risk for in-stent restenosis in patients with acute myocardial infarction. 452 patients with acute myocardial infarction admitted to our hospital between June 2018 and June 2020 were prospectively selected as subjects. All patients underwent percutaneous coronary intervention. The baseline data of the patients were collected. Venous blood was taken before, 24 hours, and 3 days after the operation to detect the levels of related cytokines. Follow-up was performed for 1 year. The patients were assigned to restenosis and nonrestenosis groups according to the presence and absence of restenosis. Multivariate logistic analysis was used to explore the influencing factors of the risk for in-stent restenosis in patients with acute myocardial infarction. By July 1, 2021, 449 cases had been followed up. Of them, 44 cases suffered from in-stent restenosis and 405 cases did not affect in-stent restenosis. The incidence of in-stent restenosis was 9.80%. Before, 24 hours, and 3 days after the operation, the lipoprotein-associated phospholipase A2 (Lp-PLA2) level was significantly higher in the restenosis group than that in the nonrestenosis group. At 3 days after the operation, the interleukin 6 (IL-6) level was significantly higher in the restenosis group than that in the nonrestenosis group (P < 0.05). Multivariate logistic analysis displayed that Lp-PLA2 level preoperatively (OR = 1.048, 95% CI 1.029-1.068), Lp-PLA2 level 24 hours postoperatively (OR = 1.013, 95% CI 1.007-1.019), Lp-PLA2 level 3 days postoperatively (OR = 1.032, 95% CI 1.015-1.048), and IL-6 level 3 days postoperatively (OR = 1.020, 95% CI 1.000-1.040) were risk factors for in-stent restenosis (all P < 0.05). IL-6 and Lp-PLA2 levels can predict the risk for in-stent restenosis in patients with acute myocardial infarction in the perioperative period.

Analysis of the association and predictive value of hyperhomocysteinaemia for obstructive coronary artery disease

Objective

To investigate the predictive value of hyperhomocysteinaemia (HHcy) for obstructive coronary artery disease (CAD) in an Asian population in northern China.

Methods

This retrospective study enrolled patients at their first cardiac assessment and assigned them to an obstructive CAD group or a non-obstructive CAD group according to the coronary angiography results. HHcy was defined as a homocysteine (Hcy) level > 15 µmol/l.

Results

This study enrolled 2987 participants: 1172 in the non-obstructive CAD group and 1815 in the obstructive CAD group. Hcy level in the obstructive CAD group was significantly higher than in the non-obstructive CAD group. The proportion of patients with HHcy in the obstructive CAD group was significantly greater than in the non-obstructive CAD group. Multivariate logistic regression analysis demonstrated that HHcy was independently correlated with obstructive CAD in both young (aged ≤ 55 years) and old patients (aged > 55 years). HHcy showed a higher sensitivity (93.1%), specificity (86.1%) and accuracy (90.0%) for obstructive CAD. The odds ratio for HHcy was 84.2. The Kappa value (0.8) showed substantial agreement between obstructive CAD and HHcy.

Conclusions

HHcy was associated with obstructive CAD and may be a potentially independent risk factor for obstructive CAD with good predictive value.

Targeting the Mitochondrial Permeability Transition Pore to Prevent Age-Associated Cell Damage and Neurodegeneration

The aging process is associated with significant alterations in mitochondrial function. These changes in mitochondrial function are thought to involve increased production of reactive oxygen species (ROS), which over time contribute to cell death, senescence, tissue degeneration, and impaired tissue repair. The mitochondrial permeability transition pore (mPTP) is likely to play a critical role in these processes, as increased ROS activates mPTP opening, which further increases ROS production. Injury and inflammation are also thought to increase mPTP opening, and chronic, low-grade inflammation is a hallmark of aging. Nicotinamide adenine dinucleotide (NAD+) can suppress the frequency and duration of mPTP opening; however, NAD+ levels are known to decline with age, further stimulating mPTP opening and increasing ROS release. Research on neurodegenerative diseases, particularly on Parkinson's disease (PD) and Alzheimer's disease (AD), has uncovered significant findings regarding mPTP openings and aging. Parkinson's disease is associated with a reduction in mitochondrial complex I activity and increased oxidative damage of DNA, both of which are linked to mPTP opening and subsequent ROS release. Similarly, AD is associated with increased mPTP openings, as evidenced by amyloid-beta (Aβ) interaction with the pore regulator cyclophilin D (CypD). Targeted therapies that can reduce the frequency and duration of mPTP opening may therefore have the potential to prevent age-related declines in cell and tissue function in various systems including the central nervous system.

The Relationship Between the Level of Serum ESM-1 and Lp-PLA2 in Patients With Acute ST-Segment Elevation Myocardial Infarction

Acute ST‐segment elevation myocardial infarction (STEMI) is the most lethal coronary heart disease with vascular endothelium dysfunction and inflammation in the disease development process. Endothelial cell‐specific molecule 1 (ESM‐1) and lipoprotein‐associated phospholipase A2 (Lp‐PLA2) are important for the diagnosis and characterization of STEMI. To date, no studies have reported the correlation between ESM‐1 and Lp‐PLA2 levels in patients with STEMI, which may be an important predictor of the fatal disease. To measure the level of serum ESM‐1 and Lp‐PLA2, and to evaluate the relationship and the clinical significance of these two biomarkers in patients with acute STEMI, 37 inpatients with acute STEMI were sequentially enrolled in the research group and 24 study objects with normal coronary artery function were included in the control group. The measurement of the relative parameters was done by enzyme‐linked immunosorbent assay using blood samples taken from the median cubital vein while the inpatients were enrolled. The levels of serum SEM‐1 and Lp‐PLA2 were significantly higher in patients with acute STEMI than in study objects with normal coronary artery function (P < 0.05). A significant correlation of serum SEM‐1 and Lp‐PLA2 was observed, leading to close linearity (r² = 0.8131, P < 0.0001). In conclusion, the endothelium dysfunction factor ESM‐1 and inflammatory factor Lp‐PLA2 are significantly higher and correlated in patients with acute STEMI. These two factors could be novel and effective biomarkers for acute STEMI diagnosis and evaluation.

Mechanisms underlying the association between periodontitis and atherosclerotic disease

Atherosclerosis is central to the pathology of cardiovascular diseases, a group of diseases in which arteries become occluded with atheromas that may rupture, leading to different cardiovascular events, such as myocardial infarction or ischemic stroke. There is a large body of epidemiologic and animal model evidence associating periodontitis with atherosclerotic disease, and many potential mechanisms linking these diseases have been elucidated. This chapter will update knowledge on these mechanisms, which generally fall into 2 categories: microbial invasion and infection of atheromas; and inflammatory and immunologic. With respect to the invasion and infection of atheromas, it is well established that organisms from the subgingival biofilm can enter the circulation and lodge in most distant tissues. Bacteremias resulting from oral interventions, and even oral hygiene activities, are well documented. More recently, indirect routes of entry of oral organisms (via phagocytes or dendritic cells) have been described for many oral organisms, into many tissues. Such organisms include the periodontal pathogens Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans, Prevotella intermedia, Tannerella forsythia, and Fusobacterium nucleatum. Intracellular survival of these organisms with dissemination to distant sites (The Trojan Horse approach) has been described. Their relative contribution to atheroma formation and progression has been studied mainly in experimental research, with results demonstrating that these organisms can invade endothelial cells and phagocytic cells within the atheroma, leading to pathogenic changes and progression of the atheroma lesion. The second category of mechanisms potentially linking periodontitis to atherosclerosis includes the dumping of inflammatory mediators originating from periodontal lesions into the systemic circulation. These inflammatory mediators, such as C-reactive protein, matrix metalloproteinases, fibrinogen, and other hemostatic factors, would further accelerate atheroma formation and progression, mainly through oxidative stress and inflammatory dysfunction. Moreover, direct effects on lipid oxidation have also been described. In summary, the evidence supports the concept that periodontitis enhances the levels of systemic mediators of inflammation that are risk factors for atherosclerotic diseases.

Challenges in the local delivery of peptides and proteins for oral mucositis management

Oral mucositis, a common inflammatory side effect of oncological treatments, is a disorder of the oral mucosa that can cause painful ulcerations, local motor disabilities, and an increased risk of infections. Due to the discomfort it produces and the associated health risks, it can lead to cancer treatment restrains, such as the need for dose reduction, cycle delays or abandonment. Current mucositis management has low efficiency in prevention and treatment. A topical drug application for a local action can be a more effective approach than systemic routes when addressing oral cavity pathologies. Local delivery of growth factors, antibodies, and anti-inflammatory cytokines have shown promising results. However, due to the peptide and protein nature of these novel agents, and the several anatomic, physiological and environmental challenges of the oral cavity, their local action might be limited when using traditional delivering systems. This review is an awareness of the issues and strategies in the local delivery of macromolecules for the management of oral mucositis.

Extracellular acidification induces ROS- and mPTP-mediated death in HEK293 cells

The extracellular pH (pHe) is a key determinant of the cellular (micro)environment and needs to be maintained within strict boundaries to allow normal cell function. Here we used HEK293 cells to study the effects of pHe acidification (24 h), induced by mitochondrial inhibitors (rotenone, antimycin A) and/or extracellular HCl addition. Lowering pHe from 7.2 to 5.8 reduced cell viability by 70% and was paralleled by a decrease in cytosolic pH (pHc), hyperpolarization of the mitochondrial membrane potential (Δψ), increased levels of hydroethidine-oxidizing ROS and stimulation of protein carbonylation. Co-treatment with the antioxidant α-tocopherol, the mitochondrial permeability transition pore (mPTP) desensitizer cyclosporin A and Necrostatin-1, a combined inhibitor of Receptor-interacting serine/threonine-protein kinase 1 (RIPK1) and Indoleamine 2,3-dioxygenase (IDO), prevented acidification-induced cell death. In contrast, the caspase inhibitor zVAD.fmk and the ferroptosis inhibitor Ferrostatin-1 were ineffective. We conclude that extracellular acidification induces necroptotic cell death in HEK293 cells and that the latter involves intracellular acidification, mitochondrial functional impairment, increased ROS levels, mPTP opening and protein carbonylation. These findings suggest that acidosis of the extracellular environment (as observed in mitochondrial disorders, ischemia, acute inflammation and cancer) can induce cell death via a ROS- and mPTP opening-mediated pathogenic mechanism.

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Extracellular acidification induces mitochondrial dysfunction.

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Extracellular acidification increases intracellular ROS levels.

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Extracellular acidification stimulates protein carbonylation.

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Extracellular acidification induces mPTP opening- and ROS-dependent cell death.

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Acidosis-induced oxidative stress likely contributes to various pathologies.

Protease-Activated Receptor-2 Deficiency Attenuates Atherosclerotic Lesion Progression and Instability in Apolipoprotein E-Deficient Mice

Inflammatory mechanisms are involved in the process of atherosclerotic plaque formation and rupture. Accumulating evidence suggests that protease-activated receptor (PAR)-2 contributes to the pathophysiology of chronic inflammation on the vasculature. To directly examine the role of PAR-2 in atherosclerosis, we generated apolipoprotein E/PAR-2 double-deficient mice. Mice were fed with high-fat diet for 12 weeks starting at ages of 6 weeks. PAR-2 deficiency attenuated atherosclerotic lesion progression with reduced total lesion area, reduced percentage of stenosis and reduced total necrotic core area. PAR-2 deficiency increased fibrous cap thickness and collagen content of plaque. Moreover, PAR-2 deficiency decreased smooth muscle cell content, macrophage accumulation, matrix metallopeptidase-9 expression and neovascularization in plaque. Relative quantitative PCR assay using thoracic aorta revealed that PAR-2 deficiency reduced mRNA expression of inflammatory molecules, such as vascular cell adhesion molecule-1, intercellular adhesion molecule-1, tumor necrosis factor (TNF)-α and monocyte chemoattractant protein (MCP)-1. In vitro experiment, we found that PAR-2 deficiency reduced mRNA expression of interferon-γ, interleukin-6, TNF-α and MCP-1 in macrophage under unstimulated and lipopolysaccharide-stimulated conditions. These results suggest that PAR-2 deficiency attenuates the progression and instability of atherosclerotic plaque.

Association between Lp-PLA2 and coronary heart disease in Chinese patients

Objective

To evaluate the association between plasma lipoprotein-associated phospholipase A2 (Lp-PLA2; known to release inflammatory mediators that promote atherosclerosis) and coronary heart disease (CHD) in Chinese patients.

Methods

This observational, cross-sectional study included a patient cohort who were assessed by coronary angiography and divided into patients with coronary heart disease and patients with normal coronary angiography (controls). Data for several biochemical indicators were collected. Plasma Lp-PLA2 concentrations were measured by enzyme-linked immunosorbent assay. Univariate and multivariate logistic regression were used to analyse the association between Lp-PLA2 concentration and CHD.

Results

A total of 531 patients were included, comprising 391 with CHD and 140 with normal coronary angiography (controls). Plasma Lp-PLA2 concentration was significantly higher in patients with CHD versus controls (median, 251 µg/l versus 219 µg/l, respectively), and particularly among patients with acute myocardial infarction and stable angina pectoris (249 µg/l and 266 µg/l, respectively). Multivariate analysis showed that Lp-PLA2 ≥ 292 µg/l (upper quartile of the whole cohort) was independently associated with CHD (odds ratio 2.814, 95% confidence interval 1.519, 5.214).

Conclusion

Plasma Lp-PLA2 concentration was independently associated with CHD in Chinese patients.

Lipoprotein-associated phospholipase A2 activity and low-density lipoprotein subfractions after a 2-year treatment with atorvastatin in adolescents with type 1 diabetes

BACKGROUND

The objective of the study was to assess the effect of atorvastatin on inflammation markers and low-density lipoprotein (LDL) subfractions.

METHODS

In a prospective, randomized, double-blind pilot study involving 28 adolescents with type 1 diabetes (T1D), lipoprotein-associated phospholipase A2 (Lp-PLA2) activity, high-sensitivity C-reactive protein (hsCRP), and subfractions of LDL were measured at baseline, after 1 year and 2 years of treatment with atorvastatin (10 mg/day) vs. placebo.

RESULTS

For the atorvastatin group, we found posttreatment reductions of Lp-PLA2 activity (p<0.001), LDL cholesterol (p=0.001), non-small dense LDL cholesterol (p<0.001), total cholesterol (p<0.001), and apolipoprotein B (apo B) (p<0.001), whereas small dense LDL cholesterol and hsCRP did not change significantly.

CONCLUSIONS

In adolescents with T1D, long-term treatment with atorvastatin is safe and may reduce cardiovascular risk by significant decreases of Lp-PLA2 activity and LDL cholesterol.

Lipoprotein-associated phospholipase A2: a new marker to determine cardiovascular risk in hypercholesterolemic dyslipidaemic children

Background

Inflammation and hypercholesterolaemia contribute to atherosclerotic changes which can start in childhood. Children with hyperlipidaemias are at high risk for early coronary atherosclerosis. This study evaluates the relationship between lipoprotein-associated phospholipase A2 (Lp-PLA2), carotid intima-media thickness (CIMT) and flow-mediated dilatation in hypercholesterolaemic dyslipidaemic children.

Methods

We performed a case–control study consisting of 43 cases, aged 2 to 17 years, and 24 age-matched controls. Fasting blood samples were obtained from both groups for the measurement of a lipid profile (total cholesterol, LDL-C, HDL-C and triglycerides) and Lp-PLA2 in mass units. The latter was determined with a turbidimetric immunoassay method (PlacTest, DiaDexus Inc.) applied to an automated analyser. CIMT and flow-mediated dilatation measurements were undertaken by a paediatric cardiologist, using high-resolution B-mode ultrasonography.

Results

Total cholesterol, LDL-C and Lp-PLA2 concentrations were significantly higher in the cases than in the controls ( p < 0.001 for all three parameters). While CIMT values were also significantly higher in the patients compared to the controls ( P = 0.001), flow-mediated dilatation values were significantly lower ( P = 0.001). We found positive correlations between Lp-PLA2 and total cholesterol ( r = 0.41, P = 0.001), Lp-PLA2 and LDL-C ( r = 0.36, P = 0.004), Lp-PLA2 and CIMT ( r = 0.44, P = 0.019) and LDL-C and CIMT ( r = 0.41, P = 0.032); there were negative correlations between Lp-PLA2 and flow-mediated dilatation ( r = −0.15, P = 0.045), total cholesterol and flow-mediated dilatation ( r = −0.45, P = 0.017), LDL-C and flow-mediated dilatation ( r = −0.51, P = 0.006) and CIMT and flow-mediated dilatation ( r = −0.45, P = 0.016).

Conclusion

Lp-PLA2 concentrations are significantly elevated in hypercholesterolaemic dyslipidaemic children. Given the association of Lp-PLA2 with markers of atherosclerosis (total cholesterol, LDL-C, CIMT and flow-mediated dilatation), the finding of increased concentrations of Lp-PLA2 could be used to identify early atherosclerotic changes in hypercholesterolaemic dyslipidaemic children and may inform their clinical management.

279(Val→Phe) Polymorphism of lipoprotein-associated phospholipase A(2) resulted in changes of folding kinetics and recognition to substrate

INTRODUCTION

PLA2G7 encodes Lp-PLA2 having role in the formation of atherosclerotic plaques by catalyzing its substrate, phosphatydilcholine (PC), to be pro-inflammatory substances. The increased risk for coronary artery disease (CAD) in Asian population has been related with this enzyme. 279(Val→Phe) variant was reported to have a protective role against CAD due to, in part, secretion defect or loss of enzymatic function. Therefore, We study folding kinetics and enzyme-substrate interaction in 279(Val→Phe) by using clinical and computational biology approach.

METHODS

Polymorphisms were detected by genotyping among 103 acute myocardial infarction patients and 37 controls. Folding Lp-PLA2 was simulated using GROMACS software by assessing helicity, hydrogen bond formation and stability. The interactions of Lp-PLA2 and its substrate were simulated using Pyrx software followed by molecular dynamics simulation using YASARA software.

RESULT

Polymorphism of 279(Val→Phe) was represented by the change of nucleotide from G to T of 994th PLA2G7 gene. The folding simulation suggested a decreased percentage of α-helix, hydrogen bond formation, hydrogen bond stability and hydrophobicity in 279(Val→Phe). The PC did not interact with active site of 279(Val→Phe) as paradoxically observed in 279 valine. 279(Val→Phe) polymorphism is likely to cause unstable binding to the substrate and decrease the enzymatic activity as observed in molecular dynamics simulations. The results of our computational biology study supported a protected effect of 279(Val→Phe) Polymorphism showed by the odd ratio for MI of 0.22 (CI 95% 0.035-1.37) in this study.

CONCLUSION

279(Val→Phe) Polymorphism of Lp-PLA2 may lead to decrease the enzymatic activity via changes of folding kinetics and recognition to its substrate.

[Lp-PLA2, a biomarker of vascular inflammation and vulnerability of atherosclerosis plaques]

A chronic inflammation is involved in various stages of development of the atherosclerotic plaques. Among the emerging biomarkers of atherogenesis, the lipoprotein-associated phospholipase A2 (Lp-PLA2), formerly known as PAF-acetylhydrolase (McIntyre et al., 2009), hydrolyses the oxidized short chain phospholipids of low-density lipoproteins (LDL), thereby releasing pro-inflammatory mediators (lysophospholipids and oxidized fatty acids). Lp-PLA2, produced by monocytes/macrophages and T-lymphocytes, and mainly associated with LDL (Gazi et al., 2005), is predominantly expressed in the necrotic center of the atherosclerotic plaques and in the macrophage-rich areas (Kolodgie et al., 2006). It would have a predictive role of cardiovascular (CV) events in relation to the vulnerability of atherosclerotic plaques. Determination of Lp-PLA2 has been proposed in the assessment of the CV risk, to ensure a better stratification of populations at intermediate risk for targeted therapy (Davidson et al., 2008). Its proatherogenic role suggested that inhibition of its activity could ensure a better vascular protection in combination with cholesterol-lowering agents. Nevertheless, Lp-PLA2 is not yet a fully validated marker for use in daily clinical practice, especially since the studies using an inhibitor of Lp-PLA2 (darapladib) (STABILITY Investigators et al., 2014; O'Donoghue et al., 2014) did not show any reduction in coronary events. Lp-PLA2 could have a site-specific role in plaque inflammation and development (Fenning et al., 2015). High Lp-PLA2 activity could reflect a response to pro-inflammatory stress characteristic of atherosclerosis (Marathe et al., 2014). This presentation aims at clarifying the involvement of Lp-PLA2 in the pathophysiology of atherosclerosis, and at assessing its interest both as a biomarker for the onset of CV events and as a therapeutic target.

Single and Multiple Dose Pharmacokinetics, Pharmacodynamics and Safety of the Novel Lipoprotein-Associated Phospholipase A2 Enzyme Inhibitor Darapladib in Healthy Chinese Subjects: An Open Label Phase-1 Clinical Trial

Background and Objectives

Darapladib is a lipoprotein-associated phospholipase A₂ (Lp-PLA₂) inhibitor. This study evaluated the pharmacokinetics, pharmacodynamics and safety of darapladib in healthy Chinese subjects.

Methods

Twenty-four subjects received darapladib 160 mg orally, approximately 1 hour after a standard breakfast, as a single dose and once daily for 28 days. Non-compartmental methods were used to determine the single and multiple dose pharmacokinetics of darapladib and its metabolite SB-553253. Repeat dose Lp-PLA₂ activity and safety were evaluated.

Results

Systemic exposure (AUC_(0-T), Cmax geometric mean (CVb%)) of darapladib was higher after multiple-dosing (519 ng.h/mL (33.3%), 34.4 ng/mL (49.9%)) compared to single-dose administration (153 ng.h/mL (69.0%), 17.9 ng/mL (55.2%). The steady-state accumulation ratio was less than unity (Rs = 0.80), indicating time-dependent pharmacokinetics of darapladib. Darapladib steady-state was reached by Day 14 of once daily dosing. Systemic exposure to SB-553253 was lower than darapladib with median (SB-553253: darapladib) ratios for AUC_(0-τ) of 0.0786 for single dose and 0.0532 for multiple dose administration. On Day 28, pre-dose and maximum inhibition of Lp-PLA₂ activity was approximately 70% and 75% relative to the baseline value, respectively and was dependent of darapladib concentration. The most common adverse events (≥ 21% subjects) were abnormal faeces, abnormal urine odour, diarrhoea and nasopharyngitis.

Conclusion

Darapladib 160 mg single and repeat doses were profiled in healthy Chinese subjects. Single dose systemic exposure to darapladib in healthy Chinese subjects was consistent with that observed previously in Western subjects whereas steady-state systemic exposure was approximately 65% higher in Chinese than Western subjects. The Lp-PLA₂ activity and adverse event profile were similar in healthy Chinese and previous reports in Western subjects. Ethnic-specific dose adjustment of darapladib is not considered necessary for the Chinese population.

Trial Registration

ClinicalTrials.gov NCT02000804