Melatonin suppresses atherosclerosis by ferroptosis inhibition via activating NRF2 pathway.

Melatonin (MLT), a conserved small indole compound, exhibits anti-inflammatory and antioxidant properties, contributing to its cardioprotective effects. Lipoprotein-associated phospholipase A2 (Lp-PLA2) is associated with atherosclerosis disease risk, and is known as an atherosclerosis risk biomarker. This study aimed to investigate the impact of MLT on Lp-PLA2 expression in the atherosclerotic process and explore the underlying mechanisms involved. In vivo, ApoE-/- mice were fed a high-fat diet, with or without MLT administration, after which the plaque area and collagen content were assessed. Macrophages were pretreated with MLT combined with ox-LDL, and the levels of ferroptosis-related proteins, NRF2 activation, mitochondrial function, and oxidative stress were measured. MLT administration significantly attenuated atherosclerotic plaque progression, as evidenced by decreased plaque area and increased collagen. Compared with those in the high-fat diet (HD) group, the levels of glutathione peroxidase 4 (GPX4) and SLC7A11 (xCT, a cystine/glutamate transporter) in atherosclerotic root macrophages were significantly increased in the MLT group. In vitro, MLT activated the nuclear factor-E2-related Factor 2 (NRF2)/SLC7A11/GPX4 signaling pathway, enhancing antioxidant capacity while reducing lipid peroxidation and suppressing Lp-PLA2 expression in macrophages. Moreover, MLT reversed ox-LDL-induced ferroptosis, through the use of ferrostatin-1 (a ferroptosis inhibitor) and/or erastin (a ferroptosis activator). Furthermore, the protective effects of MLT on Lp-PLA2 expression, antioxidant capacity, lipid peroxidation, and ferroptosis were decreased in ML385 (a specific NRF2 inhibitor)-treated macrophages and in AAV-sh-NRF2 treated ApoE-/- mice. MLT suppresses Lp-PLA2 expression and atherosclerosis processes by inhibiting macrophage ferroptosis and partially activating the NRF2 pathway.

Lipoprotein-associated phospholipase A2 predicts cardiovascular death in patients on maintenance hemodialysis: a 7-year prospective cohort study.

BACKGROUND: Cardiovascular diseases (CVD) is the leading cause of death among maintenance hemodialysis patients, with dyslipidemia being a prevalent complication. The paradoxical relationship between cardiovascular outcomes and established lipid risk markers, such as low-density lipoprotein cholesterol (LDL-C), complicates lipid management in this population. This study investigated Lipoprotein-associated phospholipase A2 (Lp-PLA2), an emerging biomarker known for its proinflammatory and proatherogenic properties, as a potential cardiovascular prognostic marker in this cohort. In this context, the association between Lp-PLA2 levels and cardiovascular outcomes was evaluated, with the aim to facilitate more accurate stratification and identification of high-risk individuals. METHODS: From August 2013 to January 2014, 361 hemodialysis patients were prospectively enrolled. Lp-PLA2 activity and laboratory measures at baseline were quantified. Comorbidities and medications were recorded. All patients were followed until the end of April, 2022. The individual and combined effects of Lp-PLA2 activity and LDL-C on patient outcomes were examined. The association between Lp-PLA2 activity and all-cause mortality, cardiovascular mortality, and major adverse cardiovascular events (MACEs) was analyzed. RESULTS: The median Lp-PLA2 activity was 481.2 U/L. In subjects with Lp-PLA2 activity over 481.2 U/L, significantly higher total cholesterol (4.89 vs. 3.98 mmol/L; P < 0.001), LDL-C (3.06 vs. 2.22 mmol/L; P < 0.001), and apolipoprotein B (0.95 vs. 0.75 mmol/L; P < 0.001) were observed. Over a median follow-up of 78.1 months, 182 patients died, with 77 cases identified as cardiovascular death, 88 MACEs happened. Cardiovascular mortality and MACEs, but not all-cause mortality, were significantly increased in the high Lp-PLA2 group. Cox regression analyses showed that high Lp-PLA2 activity was associated with cardiovascular mortality and MACE occurrence. After comprehensive adjustment, high Lp-PLA2 activity was independently associated with cardiovascular mortality(as a dichotomous variable: HR:2.57, 95%CI:1.58,4.18, P < 0.001; as a continuous variable: HR:1.25, 95%CI:1.10,1.41, P = 0.001) and MACEs(as a dichotomous variable: HR:2.17, 95%CI:1.39,3.40, P = 0.001; as a continuous variable: HR:1.20, 95%CI:1.07,1.36, P = 0.002). When participants were grouped by median Lp-PLA2 activity and LDL-C values, those with high Lp-PLA2 and low LDL-C had the highest CV mortality. The addition of Lp-PLA2 significantly improved reclassification (as a dichotomous variable NRI = 42.51%, 95%CI: 5.0%,61.33%; as a continuous variable, NRI = 33.32%, 95% CI: 7.47%,56.21%). CONCLUSIONS: High Lp-PLA2 activity is an independent risk factor for cardiovascular mortality and MACEs occurrence in patients on hemodialysis. The combined measures of Lp-PLA2 and LDL-C help to identify individuals with a higher risk of cardiovascular death.

Lipoprotein-associated phospholipase A2 Activity Levels is Associated with Artery to Artery Embolism in Symptomatic Intracranial Atherosclerotic Disease.

BACKGROUND: Lipoprotein-associated phospholipase A2 activity (Lp-PLA2-A) is a pivotal enzyme involved in the inflammatory process and atherosclerotic plaque vulnerability. This study aimed to investigate the potential of Lp-PLA2-A as a biomarker for reflecting artery-to-artery embolism (AAE), a critical mechanism with high risk of stroke recurrence in symptomatic intracranial atherosclerotic disease (sICAD). METHODS: The current analysis included a cohort of 1,908 patients with sICAD and baseline levels of Lp-PLA2-A from the Third China National Stroke Registry (CNSR-III). The baseline Lp-PLA2-A levels were quantified centrally using an automatic enzyme assay system. Diagnosis of sICAD was made by experienced stroke neurologists based on the presence of a cerebral infarction within the territory of a stenotic (>50%) or occluded artery, or when clinical symptoms were consistent with the diagnosis. Infarct lesions affecting the cortex serve as imaging biomarkers for stroke mechanism involving AAE.The relationship between baseline Lp-PLA2-A quartile levels and the presence of cortical infarction was analyzed using multivariate logistic regression. RESULTS: Compared to patients in the first Lp-PLA2-A quartile, those in the second, third and fourth quartiles demonstrated a significantly higher proportion of AAE. The proportion of patients with cortical infarction increased with rising Lp-PLA2-A quartiles, observed at 39.3%, 47.1%, 47.4%, and 50.7% for the first, second, third and fourth quartiles respectively (P for trend=0.004). Compared with the first quartile, the odds ratios (ORs) were 1.38 (95% CI = 1.06-1.79) for the second, 1.33 (95% CI = 1.02-1.72) for the third quartile and 1.48 (95% CI = 1.14-1.92) for the fourth quartile. The association between higher Lp-PLA2-A and increased proportion of cortical infarction was also present in the subgroups defined by age <65 years, male, and high-sensitivity C-reactive protein ≥2 mg/L. In sensitivity analyses, the positive correlation between Lp-PLA2-A levels and proportion of cortical infarction remained consistent. CONCLUSIONS: This research highlights the significance of Lp-PLA2-A as a biomarker for reflecting stroke mechanism in sICAD. Additional studies are warranted to explore the potential of targeting Lp-PLA2-associated inflammatory pathways as a pivotal approach in arresting the advancement of intracranial atherosclerotic stenosis and reducing the incidence of embolic strokes.

[Lipoprotein-associated phospholipase A2 (Lp-PLA2): Relevant biomarker and therapeutic target?] / La phospholipase A2 associée aux lipoprotéines (Lp-PLA2) : biomarqueur pertinent et cible thérapeutique ?

Over the last fifteen years, numerous studies have sought to decipher the role of lipoprotein-associated phospholipase A2 (Lp-PLA2) in vascular inflammation-related diseases, notably atherosclerosis. Despite the disappointing results of clinical trials using the Lp-PLA2 inhibitor darapladib, new pathophysiological, epidemiological and genetic data have enabled the development of new inhibitors. Recent studies also show that Lp-PLA2 is involved in vascular inflammation-related diseases other than atherosclerosis (ischemic stroke, Alzheimer's disease and vascular dementia, diabetes, cancers…), and inhibition of Lp-PLA2 could have beneficial therapeutic in these diseases. This review aims to present new data on Lp-PLA2 and to evaluate its current interest as a biomarker but also as a therapeutic target.

Evaluation of ankle brachial index, serum miR-103 and LP-PLA2 in the prognosis of acute ischemic stroke.

Objective: To explore the prognostic value of ankle brachial index (ABI), serum microribonucleic acid-103 (miR-103), and lipoprotein associated phospholipase A2 (LP-PLA2) indicators in patients with acute ischemic stroke (AIS). Methods: A retrospective analysis was conducted using the medical records of 202 patients with AIS admitted to the First Affiliated Hospital of Hebei North University from June 2019 to December 2022. Patients were divided into two groups based on their prognosis: the Poor-group (n=72) and the Good-group (n=130). Levels of ABI, serum miR-103, and LP-PLA2 indicators were compared between the two groups. Multivariate logistic regression analysis was used to analyze the independent risk factors for the poor prognosis in patients with AIS, and the receiver operating characteristic (ROC) curve was used to evaluate the predictive ability of ABI, serum miR-103, and LP-PLA2 levels on the prognosis of AIS. Results: Seventy two patients had a poor prognosis (35.6%) and 130 had a good prognosis (64.4%). The Poor-group had a higher proportion of elderly patients, patients with a history of diabetes and hypertension, abnormal ABI, and elevations in serum miR-103 and LP-PLA2 compared to the Good-group (P<0.05). Multivariate logistic regression analysis showed that abnormal ABI, and high levels of serum miR-103 and LP-PLA2 were independent risk factors for the poor prognosis. ROC curve provided a combined AUC of 0.862, which was higher than that of the individual ABI, serum miR-103, and LP-PLA2 curves, with values of 0.625, 0.749, and 0.696, respectively (P<0.05). Conclusions: Abnormal ABI, and high serum miR-103 and LP-PLA2 levels are independent risk factors for poor prognosis in AIS patients. They can be used as important indicators for predicting the prognosis of AIS.

Phenotypic changes in low-density lipoprotein particles as markers of adverse clinical outcomes in COVID-19.

BACKGROUND AND AIMS: Low-density lipoprotein (LDL) plasma concentration decline is a biomarker for acute inflammatory diseases, including coronavirus disease-2019 (COVID-19). Phenotypic changes in LDL during COVID-19 may be equally related to adverse clinical outcomes. METHODS: Individuals hospitalized due to COVID-19 (n = 40) were enrolled. Blood samples were collected on days 0, 2, 4, 6, and 30 (D0, D2, D4, D6, and D30). Oxidized LDL (ox-LDL), and lipoprotein-associated phospholipase A2 (Lp-PLA2) activity were measured. In a consecutive series of cases (n = 13), LDL was isolated by gradient ultracentrifugation from D0 and D6 and was quantified by lipidomic analysis. Association between clinical outcomes and LDL phenotypic changes was investigated. RESULTS: In the first 30 days, 42.5% of participants died due to Covid-19. The serum ox-LDL increased from D0 to D6 (p < 0.005) and decreased at D30. Moreover, individuals who had an ox-LDL increase from D0 to D6 to over the 90th percentile died. The plasma Lp-PLA2 activity also increased progressively from D0 to D30 (p < 0.005), and the change from D0 to D6 in Lp-PLA2 and ox-LDL were positively correlated (r = 0.65, p < 0.0001). An exploratory untargeted lipidomic analysis uncovered 308 individual lipids in isolated LDL particles. Paired-test analysis from D0 and D6 revealed higher concentrations of 32 lipid species during disease progression, mainly represented by lysophosphatidyl choline and phosphatidylinositol. In addition, 69 lipid species were exclusively modulated in the LDL particles from non-survivors as compared to survivors. CONCLUSIONS: Phenotypic changes in LDL particles are associated with disease progression and adverse clinical outcomes in COVID-19 patients and could serve as a potential prognostic biomarker.

Lipoprotein associated- phospholipase A2 in STEMI vs. NSTE-ACS patients: a marker of cardiovascular atherosclerotic risk rather than thrombosis.

The precise role of Lipoprotein associated phospholipase A2 (Lp-PlA2) in the pathogenesis of acute coronary syndromes (ACS) and in the prediction of future cardiovascular events is still debated. So far, few data exist on the variations of Lp-PlA2 activity in ACS and especially in NSTE-ACS vs. STEMI patients, where thrombotic and atherosclerotic mechanisms could play a differential role. The aim of the present study was, then, to compare Lp-PlA2 activity according to the type of ACS presentation. METHODS: A consecutive cohort of patients undergoing coronary angiography for acute coronary syndrome (ACS) were included and divided according to presentation for non ST-segment elevation-ACS or ST-segment elevation Myocardial Infarction (STEMI). Lp-PLA2 activity was assessed in blood samples drawn at admission using the Diazyme Lp-PlA2 Activity Assay. RESULTS: We included in our study 117 patients, of whom 31 (26.5%) presented with STEMI. STEMI patients were significantly younger (p = 0.05), displayed a lower rate of hypertension (p = 0.002), previous MI (p = 0.001) and PCI (p = 0.01) and used less frequently statins (p = 0.01) and clopidogrel (p = 0.02). White blood cells and admission glycemia were increased in STEMI (p = 0.001, respectively). The prevalence and severity of CAD was not different according to ACS types, but for a higher prevalence of thrombus (p < 0.001) and lower TIMI flow (p = 0.002) in STEMI. The levels of Lp-PlA2 were significantly lower in STEMI as compared to NSTE-ACS patients, (132 ± 41.1 vs. 154.6 ± 40.9 nmol/min/mL, p = 0.01). In fact, the rate of patients with Lp-PlA2 above the median (148 nmol/min/mL) was significantly lower in STEMI patients as compared to NSTE-ACS (32.3% vs. 57%, p = 0.02, adjusted OR[95% CI] = 0.20[0.06-0.68], p = 0.010). Moreover, a direct linear relationship was observed between Lp-PlA2 and LDL-C (r = 0.47, p < 0.001), but not with inflammatory biomarkers. CONCLUSION: The present study shows that among ACS patients, the levels of Lp-PlA2 are inversely associated with STEMI presentation and thrombotic coronary occlusion, being instead increased in NSTE-ACS patients, therefore potentially representing a marker of more aggressive chronic cardiovascular disease with an increased risk of recurrent cardiovascular events.

Age- and Sex-Specific Association between Lipoprotein-Related Phospholipase A2 and Cardiometabolic Risk Factors.

(1) Lipoprotein-associated phospholipase A2 (Lp-PLA2) is a risk factor for predicting cardiovascular diseases. Metabolic syndrome is characterized by a state of chronic inflammation that is related to an increased risk of cardiovascular events and death. In the present study, we aimed to analyze the correlation between cardiometabolic risk factors and Lp-PLA2 levels. (2) We collected the related retrospective medical data of Chinese adults, of which 3983 were men and 2836 were women (aged ≥ 18 years), who underwent health check-ups, and discussed the sex and age-related differences. (3) Data analysis showed that Lp-PLA2 was significantly related to lipoproteins and glutamic pyruvic transaminase (GPT), and that a linear trend was observed with increasing Lp-PLA2 levels for all ages and sexes. However, fasting glucose was significantly related to Lp-PLA2 only in the younger population. The two obesity-related parameters (waist-to-height ratio and waist circumference) also had a greater correlation with Lp-PLA2 levels in the younger groups; however, the correlation weakened in the elderly population. Meanwhile, the correlation between mean arterial pressure and creatinine level and Lp-PLA2 was significant only in younger men. (4) The results show that the expression patterns of Lp-PLA2 differ between sexes and across age groups.

Lipoprotein-Associated Phospholipase A2 has Comparable Ability as Anthropometric Indices to Discriminate Cardiovascular Disease Risk: A Cross-Sectional Study.

BACKGROUND AND AIM: Available evidence suggests that the indices of obesity may serve as good predictors of cardiovascular disease (CVD). This study compared the ability of lipoprotein-associated phospholipase A2 (Lp-PLA2) and anthropometric indices to discriminate CVD risk among the apparently healthy staff of Babcock University in Southwest Nigeria. METHODS: A descriptive cross-sectional study was conducted among apparently healthy staff. Participants' weight, height, body mass index (BMI), waist circumference (WC), hip circumference (HC), neck circumference (NC), waist-to-hip ratio (WHR), waist-to-height ratio (WHtR), wrist circumference (WrC), and blood pressure were measured. Venous blood was collected for Lp-PLA2, lipid profile, and fasting plasma glucose (FPG) estimation. CVD risk was defined as the presence of either general obesity or abdominal obesity, diabetes mellitus, dyslipidaemia, hypertension or smoking. The receiver operating characteristic curve was used to compare the ability of LpPLA2 and the anthropometric indices to discriminate CVD risk in male and female participants. RESULTS: Results showed that 75.7% (106) of the participants had CVD risk. Anthropometric indices (weight, BMI, WC, HC, NC, WrC, WHR, and WHtR), FPG, lipid profile and Lp-LPA2 were higher among participants with CVD risk (p<0.05). Among the men, LpPLA2 had the largest area under the curve (AUC) (AUC= 0.886, p<0.001), closely followed by BMI (AUC = 0.879, p<0.001), WC (AUC = 0.864, p<0.001), and WHtR (AUC= 0.866, p<0.001). Among the women, WHtR had the largest AUC of 0.995 (p<0.001), followed by WC (AUC = 0.990, p<0.001), BMI (AUC = 0.970, p<0.001), and Lp-PLA2 (AUC= 0.938, p<0.001). CONCLUSION: The abilities of Lp-PLA2 and anthropometric indices to predict CVD risk are comparable among the male and female apparently healthy staff of a private tertiary university in Southwest Nigeria. CONTEXTE ET OBJECTIF: Les données disponibles suggèrent que les indices d'obésité peuvent servir de bons prédicteurs des maladies cardiovasculaires (MCV). Cette étude a comparé la capacité de la phospholipase A2 associée aux lipoprotéines (Lp-PLA2) et des indices anthropométriques à discriminer le risque de MCV parmi le personnel apparemment en bonne santé de l'Université Babcock, dans le sud-ouest du Nigeria. MÉTHODES: Une étude descriptive transversale a été menée auprès de membres du personnel apparemment en bonne santé. Le poids, la taille, l'indice de masse corporelle (IMC), le tour de taille (WC), le tour de hanches (HC), le tour de cou (NC), le rapport taille-hanche (WHR), le rapport taille-hauteur (WHtR), le tour de poignet (WrC) et la pression artérielle des participants ont été mesurés. Du sang veineux a été prélevé pour mesurer la Lp-PLA2, le profil lipidique et la glycémie à jeun. Le risque de MCV a été défini comme la présence d'une obésité générale ou d'une obésité abdominale, d'un diabète sucré, d'une dyslipidémie, d'une hypertension ou d'un tabagisme. La courbe caractéristique du récepteur a été utilisée pour comparer la capacité de la Lp-PLA2 et des indices anthropométriques à discriminer le risque de MCV chez les hommes et les femmes. RÉSULTATS: Les résultats ont montré que 75,7 % (106) des participants présentaient un risque de MCV. Les indices anthropométriques (poids, IMC, tour de taille, HC, NC, WrC, WHR et WHtR), la glycémie, le profil lipidique et la Lp-LPA2 étaient plus élevés chez les participants présentant un risque de MCV (p<0,05). Chez les hommes, la Lp-PLA2 présentait la plus grande aire sous la courbe (AUC) (AUC = 0,886, p<0,001), suivie de près par l'IMC (AUC = 0,879, p <0,001), le tour de taille (AUC = 0,864, p <0,001) et le WHtR (AUC = 0,866, p <0,001).Chez les femmes, le WHtR présentait la plus grande aire sous la courbe de 0,995 (p<0,001), suivi du tour de taille (aire sous la courbe de 0,990, p<0,001), de l'IMC (aire sous la courbe de 0,970, p<0,001) et de la LpPLA2 (aire sous la courbe de 0,938, p<0,001). CONCLUSION: Les capacités de Lp-PLA2 et des indices anthropométriques à prédire le risque de MCV sont comparables parmi le personnel masculin et féminin apparemment en bonne santé d'une université tertiaire privée du sud-ouest du Nigeria. Mots-clés: Phospholipase A2 associée aux lipoprotéines, indices anthropométriques, risque cardiovasculaire, Nigeria.

Correlation between smoking and serum lipoprotein-associated phospholipase A2 level in overweight and obese men. / è¶ é‡å’Œè‚¥èƒ–ç”·æ€§å¸çƒŸä¸Žè¡€æ¸ è„‚è›‹ç™½ç›¸å ³ç£·è„‚é ¶A2çš„ç›¸å ³æ€§.

OBJECTIVES: Lipoprotein-associated phospholipase A2 (Lp-PLA2) is a vaso-specific inflammatory marker that exacerbates atherosclerotic through inflammatory responses. It can be used to predict the occurrence of adverse cardiovascular events and to assess the residual risk of cardiovascular diseases. This study aims to investigate the correlation between smoking and serum Lp-PLA2 levels in overweight and obese men, and to provide evidence for preventing the cardiovascular diseases. METHODS: Male subjects, who participated in health examination at the Health Management Center, Third Xiangya Hospital, Central South University from May 1, 2020 to April 30, 2021, were selected. The smoking status and other information were collected by the Self-test Scale of Physical Examination. According to the smoking status, they were divided into a never-smoking group, a current smoking group, a quit smoking group and a passive smoking group. According to the daily smoking amount, the current smoking subjects were divided into a <10 cigarettes group, a 10 to 20 cigarettes group, a 21 to 30 cigarettes group, and a >30 cigarettes group. According to the smoking years, the current smoking subjects were divided into a <5 years group, a 5 to 10 years group, a 11 to 20 years group, and a >20 years group.Serum Lp-PLA2 levels and other clinical indexes in different smoking groups were measured and compared, the correlation between smoking and serum Lp-PLA2 levels in overweight and obese men was analyzed by logistic regression analysis. RESULTS: Serum Lp-PLA2 levels were significantly different between the never-smoking group and the current smoking group (P<0.05). Logistic regression analysis showed that, before adjusting other influencing factors and in terms of smoking status, the current smoking group (OR=1.81, 95% CI 1.27 to 2.58, P<0.01) and the quit smoking group (OR=2.09, 95% CI 1.12 to 3.90, P<0.05) were positively correlated with serum Lp-PLA2 levels compared with the never-smoking group, while the passive smoking group had no correlation with serum Lp-PLA2 levels (OR=1.27, 95% CI 0.59 to 2.73, P>0.05). In terms of daily smoking amount, the 10 to 20 cigarettes group (OR=2.09, 95% CI 1.40 to 3.12, P<0.001) and the 21 to 30 cigarettes group (OR=1.98, 95% CI 1.22 to 3.20, P<0.01) were positively correlated with serum Lp-PLA2 levels compared with the never-smoking group, while the <10 cigarettes group (OR=1.45, 95% CI 0.81 to 2.60, P>0.05) and the >30 cigarettes group (OR=1.17, 95% CI 0.60 to 2.28, P>0.05) had no correlation with serum Lp-PLA2 levels. In terms of smoking years, the 5 to 10 years group (OR=1.94, 95% CI 1.07 to 3.53, P<0.05), the 11 to 20 years group (OR=2.06, 95% CI 1.33 to 3.18, P<0.01), and the >20 years group (OR=1.66, 95% CI 1.11 to 2.47, P<0.05) were positively correlated with serum Lp-PLA2 levels compared with the never-smoking group, while the <5 years group had no correlation with serum Lp-PLA2 levels (OR=1.12, 95% CI 0.38 to 3.33, P>0.05). After adjusting for age and other indicators, the correlation between smoking years and serum Lp-PLA2 levels was the same as before adjustment among the above smoking groups, except that the correlation between the smoking 5 to 10 years group and serum Lp-PLA2 levels was not significant (OR=1.77, 95% CI 0.95 to 3.29, P>0.05). CONCLUSIONS: Smoking is correlated with serum Lp-PLA2 levels in overweight and obese men.

Establishment and clinical application of time-resolved immunofluorescence assay of lipoprotein-associated phospholipase A2.

AIM: This study aimed to establish a highly sensitive time-resolved fluorescence immunoassay (TRFIA) for the detection of serum lipoprotein-associated phospholipase A2 (Lp-PLA2) and evaluate the clinical application value of Lp-PLA2 in patients with breast cancer. METHODS: The level of Lp-PLA2 was detected using the double-antibody sandwich method. First, the Lp-PLA2-TRFIA method was established, and the method was evaluated on the basis of linearity, sensitivity, precision, specificity, and recovery rate. Then, the fluorescence counts in serum of healthy subjects and patients with breast cancer were detected by Lp-PLA2-TRFIA, and the levels of Lp-PLA2 were calculated using a standard curve. RESULTS: Lp-PLA2-TRFIA had a wide linear range (43.48-2000 ng/mL). The intra-assay precisions of Lp-PLA2-TRFIA ranged from 2.66% to 4.84% (<10%), and the inter-assay precisions were between 5.39% and 6.95% (<15%). No cross-reaction was observed among Lp-PLA2, Tumor-associated trypsinogen-2, and T-cell immunoglobulin mucin 3. In addition, the recovery rates were between 90% and 100%. The serum Lp-PLA2 levels of patients with breast cancer were significantly higher than those of healthy subjects. CONCLUSIONS: We successfully established a highly sensitive Lp-PLA2-TRFIA method, and found serum Lp-PLA2 may be associated with dyslipidemia in breast cancer and could be used for auxiliary diagnose.

Circulating Biomarkers Predict Symptomatic but Not Asymptomatic Carotid Artery Stenosis.

BACKGROUND: Subjects exposed to risk factors such as age, gender, hypertension, diabetes mellitus, and smoking are prone to atherosclerotic events. AIMS: The main aim of this longitudinal cohort study was to determine whether the role of novel plasma biomarkers for atherosclerotic carotid artery disease is different in subjects developing symptomatic carotid artery stenosis (CAS), as opposed to those with incident asymptomatic CAS. METHODS: The following biomarkers were measured in 5,550 middle-aged subjects in a population-based cohort study: C-reactive protein (CRP), lipoprotein-associated phospholipase A2 mass and activity, proneurotensin, midregional proadrenomedullin (MR-proADM), midregional proatrial natriuretic peptide (MR-proANP), N-terminal pro-B-type natriuretic peptide (NT pro-BNP), copeptin, and cystatin C. After exclusion of those with prevalent CAS, subjects were thereafter followed in national patient registers for 23.4 (interquartile range 19.5-24.3) years regarding incident symptomatic and asymptomatic CAS. RESULTS: Among 110 patients with confirmed incident CAS, 56 were symptomatic and 54 were asymptomatic. When including conventional risk markers in a Cox regression analysis, NT pro-BNP (hazard ratio [HR] 1.59; 95% confidence interval [CI]: 1.20-2.11), MR-proADM (HR 1.40; CI: 1.13-1.73), cystatin C (HR 1.21; CI: 1.02-1.43), and CRP (HR 1.53; CI: 1.13-1.73) were independently associated with incident symptomatic CAS, whereas no plasma biomarker was associated with incident asymptomatic CAS. CONCLUSION: Plasma biomarkers NT pro-BNP, MR-proADM, cystatin C, and CRP were independently associated with incident symptomatic CAS, whereas no such association could be demonstrated with incident asymptomatic CAS. As these biomarkers indicate future development of clinically relevant atherosclerotic CAS, their potential utility in relation to intensified preventive measures and selection of potential candidates for carotid surgery should be further evaluated.

Correlation of lipoprotein-associated phospholipase A2 and cerebral microbleeds in patients with acute ischaemic stroke.

BACKGROUND AND AIMS: Cerebral microbleeds (CMBs) increase the risk of stroke occurrence and recurrence,and affect the prognosis of stroke patients. Therefore, identifying biological markers that predict CMBs after stroke is urgently needed. This study explored whether high levels of lipoprotein-associated phospholipase A2(Lp-PLA2) are associated with an increased risk of CMBs in patients with acute ischaemic stroke (AIS). METHODS: From April 2020 to October 2021, we enrolled 242 patients with AIS. At admission, the plasma levels of Lp-PLA2 were measured in all patients as well as the number of CMBs and white matter lesions. According to the results of the Susceptibility Weighted Imaging (SWI), the patients were divided into a CMB group and a no-CMB group. The groups were compared with univariate and multivariate analyses to clarify the correlation between Lp-PLA2 levels and CMBs, and the optimal cut-off value of Lp-PLA2 that predicted CMBs was determined from the receiver-operating characteristic curve. RESULTS: CMBs were detected in 71 (29.3%) of the 242 AIS patients. The median Lp-PLA2 level was 182.79 ng/ml. Using the 1st quartile of Lp-PLA2 levels (the lowest levels) as the reference group, univariate logistic regression analysis showed that individuals in the 4th quartile (the highest levels) had a higher risk of CMBs (odds ratio [OR] = 1.460, 95% confidence interval [CI]: 1.188-1.795, P = 0.000). This correlation persisted after adjusting for relevant risk factors (OR = 1.370, 95% CI: 1.096-1.713, P = 0.006). The optimal cut-off value of Lp-PLA2 that predicted the occurrence of CMBs was 184.36 ng/ml; at this threshold, the sensitivity was 69.0%, and the specificity was 60.2%. CONCLUSIONS: Our data suggest that a high level of Lp-PLA2 in patients with AIS is a potential risk factor for CMBs.

Increased sedentary time and decreased physical activity increases lipoprotein associated phospholipase A2 in obese individuals.

BACKGROUND AND AIMS: Lipoprotein-associated Phospholipase A2 (Lp-PLA2) is a protein produced by inflammatory cells in circulation and is associated with cardiovascular disease (CVD) risk. Physical activity (PA) is known to reduce inflammation and risk for CVD. However, Lp-PLA2 has yet to be examined in relation to PA and sedentary time. The purpose of this study was to determine if PA and sedentary time impacts Lp-PLA2 mass. A total of 25 subjects with an average BMI of 30.6 ± 5.7 were included in the data analysis. METHODS AND RESULTS: Data collected included anthropometric data, Lp-PLA2 mass, peak oxygen uptake (VO2peak), resting heart rate and blood pressure, obstructive sleep apnea (OSA) risk, and assessment of PA using an accelerometer. Sedentary minutes per day was positively associated with Lp-PLA2 (r = 0.41, P < 0.05). Light intensity PA was negatively associated (r = -0.51. P = 0.01) with Lp-PLA2. When subjects were divided into 2-quantiles by Lp-PLA2, the group with the higher Lp-PLA2 mass accumulated more sedentary time per day (P < 0.001) and less light intensity PA per day (P = 0.001). OSA risk and Lp-PLA2 showed no relationship. Sedentary behavior was higher, and light intensity PA was lower in subjects with hiLp-PLA2 mass. No difference was seen in moderate-to-vigorous intensity PA or steps per day. CONCLUSIONS: This suggests that, total PA habits, including time spent sedentary and lower intensity PA, impacts the levels of Lp-PLA2, an important inflammatory marker and marker of CVD risk.

Effects of flaxseed consumption on plasma lipids, lipoprotein-associated phospholipase A2 activity and gut microbiota composition in patients with coronary artery disease.

Background: Clinical studies have demonstrated possible beneficial effects of flaxseed on cardiovascular disease risk factors, but limited studies have evaluated the effects of flaxseed on the plasma lipoprotein-associated phospholipase A2 (Lp-PLA2) and gut microbial composition in patients with coronary artery disease (CAD). Aim: The purpose of the present study was to examine the effect of flaxseed consumption on plasma lipids and lipoproteins, Lp-PLA2 activity, as well as the relative abundance of some gut microbiota in CAD patients. Methods: In a randomized controlled parallel trial, 50 patients with CAD were randomly allocated to 12 weeks of supplementation of flaxseed (30 g/day) or control (usual care). Before and after the intervention, plasma lipids, Lp-PLA2 activity, and some gut microbiota composition (4 different bacterial genera, including Lactobacillus, Bifidobacteria, Bacteroidetes, Firmicutes) were measured. Results: Compared to control, flaxseed consumption was associated with improved Lp-PLA2 activity. After 12 weeks of intervention, no significant changes were observed in plasma lipids and fecal microbial composition in the two study groups. Conclusion: The present study showed that in patients with CAD, flaxseed supplementation reduced plasma Lp-PLA2 activity but had no effect on plasma lipids and the composition of some intestinal bacteria.

Elevated lipoprotein(a) and lipoprotein-associated phospholipase A2 are associated with unfavorable functional outcomes in patients with ischemic stroke.

BACKGROUND: The association of lipoprotein(a) [Lp(a)] and stroke functional outcomes was conflicting. The aim of the study was to clarify whether high Lp(a) is associated with unfavorable functional outcomes in patients with ischemic stroke. METHODS: A total of 9709 individuals from the third China National Stroke Registry cohort were recruited. Plasma level of Lp(a) at admission was measured with enzyme-linked immunosorbent assay. The cut-off was set at the median for Lp(a). Functional outcome was assessed using the modified Rankin scale (mRS) at 3 months and 1 year after ischemic stroke. The association between Lp(a) and functional outcomes was evaluated using a logistic regression model. RESULTS: The median age was 63.0 years, and 31.1% participants were women. Patients in higher Lp(a) group had higher incidences of unfavorable functional outcomes at 3 months. In logistic regression model, elevated Lp(a) levels were associated with unfavorable functional outcomes at 3 months (Q4 vs. Q1: odds ratio 1.33, 95% confidence interval 1.11-1.61). Subgroup analysis showed that in the lower Lp-PLA2 group, Lp(a) level was not associated with functional outcomes, but in the higher Lp-PLA2 group, Lp(a) level was significantly associated with functional outcomes. After grouped by different levels of Lp(a) and Lp-PLA2, the Lp(a) high/ Lp-PLA2 high group showed the highest incidence of unfavorable functional outcomes at 3 months and 1 year. CONCLUSIONS: Elevated Lp(a) level is associated with unfavorable functional outcomes in patients with ischemic stroke. The increment in both Lp(a) and Lp-PLA2 are associated with unfavorable functional outcomes at 3 months and 1 year after ischemic stroke.

Au-coated Fe3O4 core-shell nanohybrids with photothermal activity for point-of-care immunoassay for lipoprotein-associated phospholipase A2 on a digital near-infrared thermometer.

A portable photothermal immunoassay based on Au-coated magnetic Fe3O4 core-shell nanohybrids (Au-Fe3O4) was developed for point-of-care (POC) testing of lipoprotein-associated phospholipase A2 (Lp-PLA2) on a digital near-infrared (NIR) thermometer. Au-Fe3O4 photothermal materials were first synthesized through reverse micelle method, and then functionalized with polyclonal rabbit anti-human Lp-PLA2 antibody. A sandwiched immunoreaction was carried out in polyclonal mouse anti-human Lp-PLA2 antibody-coated microplate using Au-Fe3O4-labeled antibody as the detection antibody. With formation of sandwich-type immunocomplex, the captured Au-Fe3O4 on the plate converted the light into heat under an 808-nm laser irradiation (1.5 W cm-2), thereby resulting in the increasing temperature of the detection solution. The temperature variations relative to surrounding temperature was determined on a portable NIR thermometer. Several labeling protocols with gold nanoparticle, Fe3O4 nanoparticle, or Au-Fe3O4 nanohybrids were investigated for determination of Lp-PLA2 and improved analytical features were achieved with the core-shell Au-Fe3O4 nanohybrids. Under optimum conditions, Au-Fe3O4-based immunoassay exhibited good photothermal responses for the detection of Lp-PLA2 with a dynamic linear range of 0.01-100 ng mL-1 at a low detection limit of 8.6 pg mL-1. Good reproducibility and intermediate precision were less than 9.7%. Other biomarkers or proteins did not interfere with responses of this system. An acceptable accuracy was acquired for analysis of human serum sample between Au-Fe3O4-based photothermal immunoassay and commercialized human Lp-PLA2 ELISA kit.

Lp-PLA2 inhibition prevents Ang II-induced cardiac inflammation and fibrosis by blocking macrophage NLRP3 inflammasome activation.

Macrophage-mediated inflammation plays an important role in hypertensive cardiac remodeling, whereas effective pharmacological treatments targeting cardiac inflammation remain unclear. Lipoprotein-associated phospholipase A2 (Lp-PLA2) contributes to vascular inflammation-related diseases by mediating macrophage migration and activation. Darapladib, the most advanced Lp-PLA2 inhibitor, has been evaluated in phase III trials in atherosclerosis patients. However, the role of darapladib in inhibiting hypertensive cardiac fibrosis remains unknown. Using a murine angiotensin II (Ang II) infusion-induced hypertension model, we found that Pla2g7 (the gene of Lp-PLA2) was the only upregulated PLA2 gene detected in hypertensive cardiac tissue, and it was primarily localized in heart-infiltrating macrophages. As expected, darapladib significantly prevented Ang II-induced cardiac fibrosis, ventricular hypertrophy, and cardiac dysfunction, with potent abatement of macrophage infiltration and inflammatory response. RNA sequencing revealed that darapladib strongly downregulated the expression of genes and signaling pathways related to inflammation, extracellular matrix, and proliferation. Moreover, darapladib substantially reduced the Ang II infusion-induced expression of nucleotide-binding oligomerization domain-like receptor with pyrin domain 3 (NLRP3) and interleukin (IL)-1ß and markedly attenuated caspase-1 activation in cardiac tissues. Furthermore, darapladib ameliorated Ang II-stimulated macrophage migration and IL-1ß secretion in macrophages by blocking NLRP3 inflammasome activation. Darapladib also effectively blocked macrophage-mediated transformation of fibroblasts into myofibroblasts by inhibiting the activation of the NLRP3 inflammasome in macrophages. Overall, our study identifies a novel anti-inflammatory and anti-cardiac fibrosis role of darapladib in Lp-PLA2 inhibition, elucidating the protective effects of suppressing NLRP3 inflammasome activation. Lp-PLA2 inhibition by darapladib represents a novel therapeutic strategy for hypertensive cardiac damage treatment.

Serum level of lipoprotein-associated phospholipase A2 is a potential biomarker of vertebrobasilar dolichoectasia and its progression to cerebral infarction.

BACKGROUND: There are no effective therapies to prevent the occurrence and progression of vertebrobasilar dolichoectasia (VBD). In this study, we investigated the relationship between serum levels of lipoprotein-associated phospholipase A2 (Lp-PLA2) and the occurrence and progression of VBD. METHODS: Sixty (60) cases without VBD and ischemia stroke were considered as Group A, 100 cases with VBD were further divided into Group B (VBD without ischemic stroke, n = 54) and Group C (VBD with first ever acute posterior circulation ischemic stroke, n = 46). Demographic data (such as gender and age) and past medical history (such as hypertension, diabetes, and smoking history) were collected. The levels of serum low-density lipoprotein cholesterol (LDL-C), hypersensitivity C reactive protein (hs-CRP), glycosylated hemoglobin (HbAlc), homocysteine (HCY), uric acid (UA), fibrinogen (Fib), and Lp-PLA2, etc. were measured. Logistic regression analysis was used to assess the related factors of VBD and ischemic stroke secondary to VBD. RESULTS: Logistic multivariate regression analysis showed that only age and the level of serum Lp-PLA2 were significantly higher in group B than those in group A (P < 0.012, P < 0.001, respectively), however, only the level of serum Lp-PLA2 was significantly higher in group C than those in group B (P < 0.001). CONCLUSIONS: The serum marker Lp-PLA2 is an independent risk factor for the occurrence of VBD and the progression of VBD to posterior circulation ischemic stroke. Whether intervening on atherosclerosis could prevent the occurrence and development of VBD needs to be further studied.

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 ß-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.