Biological profile of monocyte-derived macrophages in coronary heart disease patients: implications for plaque morphology.
ABSTRACT: The prevalence of a macrophage phenotype in atherosclerotic plaque may drive its progression and/or instability. Macrophages from coronary plaques are not available, and monocyte-derived macrophages (MDMs) are usually considered as a surrogate. We compared the MDM profile obtained from coronary artery disease (CAD) patients and healthy subjects, and we evaluated the association between CAD MDM profile and in vivo coronary plaque characteristics assessed by optical coherence tomography (OCT). At morphological analysis, MDMs of CAD patients had a higher prevalence of round than spindle cells, whereas in healthy subjects the prevalence of the two morphotypes was similar. Compared to healthy subjects, MDMs of CAD patients had reduced efferocytosis, lower transglutaminase-2, CD206 and CD163 receptor levels, and higher tissue factor (TF) levels. At OCT, patients with a higher prevalence of round MDMs showed more frequently a lipid-rich plaque, a thin-cap fibroatheroma, a greater intra-plaque macrophage accumulation, and a ruptured plaque. The MDM efferocytosis correlated with minimal lumen area, and TF levels in MDMs correlated with the presence of ruptured plaque. MDMs obtained from CAD patients are characterized by a morpho-phenotypic heterogeneity with a prevalence of round cells, showing pro-inflammatory and pro-thrombotic properties. The MDM profile allows identifying CAD patients at high risk.
Project description:BACKGROUND:Galectin-3 is a 32?kDa protein secreted by macrophages involved in processes such as cell activation, chemotaxis and phagocytosis. Galectin-3 has previously been shown to improve the ability of airway macrophages to ingest apoptotic cells (efferocytosis) in chronic obstructive pulmonary disease (COPD) and may be of interest in non-eosinophilic asthma (NEA) which is also characterised by impaired efferocytosis. It was hypothesised that the addition of exogenous galectin-3 to monocyte-derived macrophages (MDMs) derived from donors with NEA would enhance their ability to engulf apoptotic granulocytes. METHODS:Eligible non-smoking adults with asthma (n?=?19), including 7 with NEA and healthy controls (n?=?10) underwent a clinical assessment, venepuncture and sputum induction. MDMs were co-cultured with apoptotic granulocytes isolated from healthy donors with or without exogenous recombinant galectin-3 (50??g/mL) and efferocytosis was assessed by flow cytometry. Galectin-3 expression and localisation in MDMs was visualised by immunofluorescence staining and fluorescence microscopy. Galectin-3, interleukin (IL)-6 and CXCL8 secretion were measured in cell culture supernatants by ELISA and cytometric bead array. RESULTS:Baseline efferocytosis (mean (±standard deviation)) was lower in participants with asthma (33.2 (±17.7)%) compared with healthy controls (45.3 (±15.9)%; p?=?0.081). Efferocytosis did not differ between the participants with eosinophilic asthma (EA) (31.4 (±19.2)%) and NEA (28.7 (±21.5)%; p?=?0.748). Addition of galectin-3 significantly improved efferocytosis in asthma, particularly in NEA (37.8 (±18.1)%) compared with baseline (30.4 (±19.7)%; p?=?0.012). Efferocytosis was not associated with any of the clinical outcomes but was negatively correlated with sputum macrophage numbers (Spearman r?=?-?0.671; p?=?0.017). Galectin-3 was diffusely distributed in most MDMs but formed punctate structures in 5% of MDMs. MDM galectin-3 secretion was lower in asthma (9.99 (2.67, 15.48) ng/mL) compared with the healthy controls (20.72 (11.28, 27.89) ng/mL; p?=?0.044) while IL-6 and CXCL8 levels were similar. CONCLUSIONS:Galectin-3 modulates macrophage function in asthma, indicating a potential role for galectin-3 to reverse impaired efferocytosis in NEA.
Project description:The requirement to remove apoptotic cells is equally important in homeostasis and inflammatory disease. In particular, during viral infections large quantities of infected cells undergo apoptosis and need to be efficiently cleared by phagocytes to prevent secondary necrosis. Although specific roles of several apoptotic cell sensors, such as the TAM (Tyro3, Axl, MerTK) receptor family, have been characterized in mouse models, little is known about their regulation and involvement in apoptotic cell uptake (efferocytosis) by human macrophages under inflammatory conditions. We show that whereas pro-inflammatory stimuli consistently downregulated MerTK expression in human monocyte-derived macrophages (MDMs), stimuli indicative of a viral infection, interferon-? (IFN-?) and the TLR3 ligand poly(I:C), specifically induced Axl expression and promoted binding of the bridging molecule Gas6. Axl induction by IFN-? and poly(I:C) was associated with higher MDM efferocytic capacity compared to cells treated with other pro-inflammatory stimuli, such as LPS and IFN-?. While MerTK blocking antibody uniformly suppressed apoptotic cell uptake by MDMs, Axl blocking antibody significantly reduced efferocytosis by poly(I:C)-stimulated MDMs, but not by resting MDMs. Our observations demonstrate that Axl induction during viral infections contributes to maintaining macrophage capacity to engulf apoptotic cells, which may have important consequences for resolution of anti-viral immune responses.
Project description:Background Polygenic risk scores (PRSs) based on risk variants from genome-wide association studies predict coronary artery disease (CAD) risk. However, it is unknown whether the PRS is associated with specific CAD characteristics. Methods and Results We consecutively included 1645 patients with suspected stable CAD undergoing coronary computed tomography angiography. A multilocus PRS was calculated as the weighted sum of CAD risk variants. Plaques were evaluated using an 18-segment model and characterized by stenosis severity and composition (soft [0%-19% calcified], mixed-soft [20%-49% calcified], mixed-calcified [50%-79% calcified], or calcified [?80% calcified]). Coronary artery calcium score and segment stenosis score were used to characterize plaque burden. For each standard deviation increase in the PRS, coronary artery calcium score increased by 78% (P=4.1e-26) and segment stenosis score increased by 16% (P=2.4e-29) in the fully adjusted model. The PRS was associated with a higher prevalence of obstructive plaques (odds ratio [OR]: 1.78, P=5.6e-16), calcified (OR: 1.69, P=6.5e-17), mixed-calcified (OR: 1.67, P=7.3e-9), mixed-soft (OR: 1.45, P=1.6e-6), and soft plaques (OR: 1.49, P=2.5e-6), and a higher prevalence of plaque in each coronary vessel (all P<1.0e-4). However, when analyzing data on a plaque level (3007 segments with plaque in 849 patients) the PRS was not associated with stenosis severity, plaque composition, or localization (all P>0.05). Conclusions Our results suggest that polygenic risk based on large genome-wide association studies increases CAD risk through an increased burden of coronary atherosclerosis rather than promoting specific plaque features. Clinical Trial Registration URL: https://www.clinicaltrials.gov. Unique identifier: NCT02264717.
Project description:Lipoprotein Lp(a) represents an independent risk factor for coronary artery disease (CAD). However, its association with CAD burden and lipid rich plaques prone to rupture in patients with acute coronary syndrome (ACS) still remains unknown. These data aim to investigate the association among serum Lipoprotein(a) (Lpa) levels, coronary atherosclerotic burden and features of culprit plaque in patients with ACS and obstructive CAD. For his reason, a total of 500 ACS patients were enrolled for the angiographic cohort and 51 ACS patients were enrolled for the optical coherence tomography (OCT) cohort. Angiographic CAD severity was assessed by Sullivan score and by Bogaty score including stenosis score and extent index, whereas OCT plaque features were evaluated at the site of the minimal lumen area and along the culprit segment. In the angiographic cohort, Lp(a) was a weak independent predictor of Sullivan score (p<0.0001), stenosis score (p<0.0001) and extent index (p<0.0001). In the OCT cohort, patients with higher Lp(a) levels (>30 md/dl) compared to patients with lower Lp(a) levels (<30 md/dl) exhibited a higher prevalence of lipidic plaque at the site of the culprit stenosis (P=0.02), a wider lipid arc (p=0.003) and a higher prevalence of thin-cap fibroatheroma (p=0.004).
Project description:Inhalation of crystalline silica (SiO2) is a risk factor of systemic autoimmune diseases such as systemic sclerosis (SSc) and fibrotic pulmonary disorders such as silicosis. A defect of apoptotic cell clearance (i.e., efferocytosis, a key process in the resolution of inflammation) is reported in macrophages from patients with fibrotic or autoimmune diseases. However, the precise links between SiO2 exposure and efferocytosis impairment remain to be determined. Answering to this question may help to better link innate immunity and fibrosis. In this study, we first aim to determine whether SiO2 might alter efferocytosis capacities of human and mouse macrophages. We secondly explore possible mechanisms explaining efferocytosis impairment, with a specific focus on macrophage polarization and on the RhoA/ROCK pathway, a key regulator of cytoskeleton remodeling and phagocytosis. Human monocyte-derived macrophages (MDM) and C57BL/6J mice exposed to SiO2 and to CFSE-positive apoptotic Jurkat cells were analyzed by flow cytometry to determine their efferocytosis index (EI). The effects of ROCK inhibitors (Y27632 and Fasudil) on EI of SiO2-exposed MDM and MDM from SSc patients were evaluated in vitro. Our results demonstrated that SiO2 significantly decreased EI of human MDM in vitro and mouse alveolar macrophages in vivo. In human MDM, this SiO2-associated impairment of efferocytosis, required the expression of the membrane receptor SR-B1 and was associated with a decreased expression of M2 polarization markers (CD206, CD204, and CD163). F-actin staining, RhoA activation and impairment of efferocytosis, all induced by SiO2, were reversed by ROCK inhibitors. Moreover, the EI of MDM from SSc patients was similar to the EI of in vitro- SiO2-exposed MDM and Y27632 significantly increased SSc MDM efferocytosis capacities, suggesting a likewise activation of the RhoA/ROCK pathway in SSc. Altogether, our results demonstrate that SiO2 exposure may contribute to the impairment of efferocytosis capacities of mouse and human macrophages but also of MDM in SiO2-associated autoimmune diseases and fibrotic disorders such as SSc; in this context, the silica/RhoA/ROCK pathway may constitute a relevant therapeutic target.
Project description:Low association between cardiac symptoms and coronary artery disease (CAD) in patients with inflammatory joint diseases (IJD) demands for objective markers to improve cardiovascular risk stratification. Our main aim was to evaluate the prevalence and characteristics of CAD in patients with IJD with carotid artery plaques. Furthermore, we aimed to assess associations of carotid ultrasonographic findings and coronary plaques.Eighty-six patients (61% female) with IJD (55 with rheumatoid arthritis, 21 with ankylosing spondylitis and 10 with psoriatic arthritis) and carotid artery plaque were referred to coronary CT angiography (CCTA). CAD was evaluated using the modified 17-segment American Heart Association model. Calcium score, plaque composition, segment involvement score and segment stenosis score were assessed and correlated to the carotid artery plaques and cardiovascular disease risk factors in logistic and linear regression analyses. Risk prediction models were tested with various cut-off values for associating variables.Fifty-five patients (66%) had CAD assessed by CCTA and 36 (43%) of these had coronary plaques defined as either mixed or soft. Eleven patients (13%) had obstructive CAD. The best risk prediction model (area under the curve: 0.832, 95% CI 0.730 to 0.935) included the combination of variables with cut-off values: age ?55 years (OR: 12.18, 95% CI 2.80 to 53.05), the carotid-intima media thickness ?0.7 mm (OR: 4.08, 95% CI 1.20 to 13.89) and carotid plaque height ?1.5 mm (OR: 8.96, 95% CI 1.68 to 47.91), p<0.05.Presence of carotid plaque is alone not sufficient to identify patients at risk for CAD, and a combination of ultrasonographic measurements may be useful in risk stratification of patients with IJD.NCT01389388, Results.
Project description:Women with non-ST elevation myocardial infarction (NSTEMI) have similar extent of myocardial ischemia but less obstructive coronary artery disease (CAD) than their male counterparts. We tested the impact of global coronary artery plaque area and artery tortuosity on myocardial perfusion in NSTEMI patients.Coronary artery plaque area was determined by quantitative angiography in 108 patients (32% women) with NSTEMI. Myocardial perfusion was assessed by contrast echocardiography in the 17 individual left ventricular segments. Artery tortuosity was defined as ≥3 curves >45° in a main coronary artery.Age, prevalence of hypertension, and diabetes did not differ between sexes (all nonsignificant). Women had lower prevalence of ≥50% coronary artery stenosis (74% vs. 91%, p<0.05), while global coronary plaque area (35±22 vs. 43±21mm(2)) and the number of segments with hypoperfusion (6.9±3.7 vs. 7.2±3.4) did not differ between sexes (both p>0.07). In multivariate analysis, larger coronary artery plaque area was associated with a 35% higher risk for having severe myocardial hypoperfusion (odds ratio 1.35 [95% confidence interval 1.01-1.80], p<0.05) in the total study population, while no association between artery tortuosity and myocardial ischemia was found. Similar results were obtained in separate analysis among women and men.In women and men with NSTEMI, the global coronary artery plaque area was an important determinant of the severity of myocardial hypoperfusion at rest independent of presence of significant coronary stenoses. These findings may expand current understanding of NSTEMI in patients with nonobstructive CAD.
Project description:The use of antiretroviral therapy (ART) as preexposure prophylaxis (PrEP) is an effective strategy for preventing HIV acquisition. The cellular consequences of PrEP exposure, however, have not been sufficiently explored to determine potential effects on health in individuals without HIV. In this study, peripheral blood mononuclear cells (PBMCs) from people without HIV were exposed to tenofovir disoproxil fumarate (TDF) or emtricitabine (FTC) overnight. Mitochondrial mass and function were measured by flow cytometry and an Agilent XFp analyzer. Monocyte-derived macrophages (MDMs) were differentiated in 20% autologous serum for 5?days in the presence or absence of TDF or FTC, and surface markers, lipid uptake, and efferocytosis were measured by flow cytometry. MDM gene expression was measured using transcriptome sequencing (RNA-seq). Plasma lipids were measured using mass spectrometry. PBMCs exposed to TDF or FTC had decreased maximal oxygen consumption rate (OCR) and reduced mitochondrial mass. Exposure to PrEP also increased reactive oxygen species (ROS) production from monocyte subsets. Compared to MDMs cultured in medium alone, cells differentiated in the presence of TDF (829 genes) or FTC (888 genes) had significant changes in gene expression. Further, PrEP-exposed MDMs had decreased mitochondrial mass and displayed increased lipid uptake and reduced efferocytosis. Plasma biomarkers and lipid levels were also altered <i>in vivo</i> in individuals receiving a PrEP regimen. In conclusion, exposure of leukocytes to TDF or FTC resulted in decreased mitochondrial function and altered functional and transcriptional profiles. These findings may have important implications for the metabolic and immunologic consequences of PrEP in populations at risk for HIV acquisition.
Project description:Introduction:Abdominal aortic aneurysm (AAA) and coronary artery disease (CAD) share common risk factors. The objective of this study was to determine the prevalence of undiagnosed AAA in patients with angiographically diagnosed significant CAD. Patients and Methods:Male patients aged 50 years and above (including indigenous people) with angiographically diagnosed significant CAD in the recent one year were screened for AAA. Standard definition of abdominal aortic aneurysm and CAD was used. All new patients were followed up for six months for AAA events (ruptured AAA and AAA-related mortality). Results:A total of 277 male patients were recruited into this study. The total prevalence of undiagnosed AAA in this study population was 1.1% (95% CI 0.2-3.1). In patients with high-risk CAD, the prevalence of undiagnosed AAA was 1.7% (95% CI 0.3-4.8). The detected aneurysms ranged in size from 35.0mm to 63.8mm. Obesity was a common factor in these patients. There were no AAA-related mortality or morbidity during the follow-up. Although the total prevalence of undiagnosed AAA is low in the studied population, the prevalence of sub-aneurysmal aortic dilatation in patients with significant CAD was high at 6.6% (95% CI 3.9-10.2), in which majority were within the younger age group than 65 years old. Conclusion:This was the first study on the prevalence of undiagnosed AAA in a significant CAD population involving indigenous people in the island of Borneo. Targeted screening of patients with high-risk CAD even though they are younger than 65 years old effectively discover potentially harmful asymptomatic AAA and sub-aneurysmal aortic dilatations.
Project description:Importance:Inflammation is critical to atherosclerosis. Psoriasis, a chronic inflammatory disease associated with early cardiovascular events and increased aortic vascular inflammation (VI), provides a model to study the process of early atherogenesis. Fludeoxyglucose F 18 positron emission tomography/computed tomography (18F-FDG PET/CT) helps quantify aortic VI, and coronary computed tomography angiography provides coronary artery disease (CAD) assessment through evaluation of total plaque burden (TB) and noncalcified coronary plaque burden (NCB), luminal stenosis, and high-risk plaques (HRP). To our knowledge, association between aortic VI and broad CAD indices has not yet been assessed in a chronic inflammatory disease state. Such a study may provide information regarding the utility of aortic VI in capturing early CAD. Objective:To assess the association between aortic VI and CAD indices, including TB, NCB, luminal stenosis, and HRP prevalence, in psoriasis. Design, Setting, and Participants:In a cross-sectional cohort study at the National Institutes of Health, 215 consecutive patients with psoriasis were recruited from surrounding outpatient dermatology practices. All patients underwent 18F-FDG PET/CT for aortic VI assessment, and 190 of 215 patients underwent coronary computed tomography angiography to characterize CAD. The study was conducted between January 1, 2013, and May 31, 2017. Data were analyzed in March 2018. Exposures:Aortic VI assessed by 18F-FDG PET/CT. Main Outcomes and Measures:Primary outcome: TB and NCB. Secondary outcomes: luminal stenosis and HRP. Results:Among 215 patients with psoriasis (mean [SD] age, 50.4 [12.6] years; 126 men [59%]), patients with increased aortic VI had increased TB (standardized β = 0.48; P < .001), and higher prevalence of luminal stenosis (OR, 3.63; 95% CI, 1.71-7.70; P = .001) and HRP (OR, 3.05; 95% CI, 1.42-6.47; P = .004). The aortic VI and TB association was primarily driven by NCB (β = 0.49; P < .001), whereas the aortic VI and HRP association was driven by low-attenuation plaque (OR, 5.63; 95% CI, 1.96-16.19; P = .001). All associations of aortic VI remained significant after adjustment for cardiovascular risk factors: aortic VI and TB (β = 0.23; P < .001), NCB (β = 0.24; P < .001), luminal stenosis (OR, 3.40; 95% CI, 1.40-8.24; P = .007), and HRP (OR, 2.72; 95% CI, 1.08-6.83; P = .03). No association was found between aortic VI and dense-calcified coronary plaque burden. Conclusions and Relevance:Aortic VI is associated with broad CAD indices, suggesting that aortic VI may be a surrogate for early CAD. Larger prospective studies need to assess these associations longitudinally and examine treatment effects on these outcomes.