How do macrophages sense modified low-density lipoproteins?

HDL Function and Atherosclerosis: Reactive Dicarbonyls as Promising Targets of Therapy

Epidemiologic studies detected an inverse relationship between HDL (high-density lipoprotein) cholesterol (HDL-C) levels and atherosclerotic cardiovascular disease (ASCVD), identifying HDL-C as a major risk factor for ASCVD and suggesting atheroprotective functions of HDL. However, the role of HDL-C as a mediator of risk for ASCVD has been called into question by the failure of HDL-C-raising drugs to reduce cardiovascular events in clinical trials. Progress in understanding the heterogeneous nature of HDL particles in terms of their protein, lipid, and small RNA composition has contributed to the realization that HDL-C levels do not necessarily reflect HDL function. The most examined atheroprotective function of HDL is reverse cholesterol transport, whereby HDL removes cholesterol from plaque macrophage foam cells and delivers it to the liver for processing and excretion into bile. Indeed, in several studies, HDL has shown inverse associations between HDL cholesterol efflux capacity and ASCVD in humans. Inflammation plays a key role in the pathogenesis of atherosclerosis and vulnerable plaque formation, and a fundamental function of HDL is suppression of inflammatory signaling in macrophages and other cells. Oxidation is also a critical process to ASCVD in promoting atherogenic oxidative modifications of LDL (low-density lipoprotein) and cellular inflammation. HDL and its proteins including apoAI (apolipoprotein AI) and PON1 (paraoxonase 1) prevent cellular oxidative stress and LDL modifications. Importantly, HDL in humans with ASCVD is oxidatively modified rendering HDL dysfunctional and proinflammatory. Modification of HDL with reactive carbonyl species, such as malondialdehyde and isolevuglandins, dramatically impairs the antiatherogenic functions of HDL. Importantly, treatment of murine models of atherosclerosis with scavengers of reactive dicarbonyls improves HDL function and reduces systemic inflammation, atherosclerosis development, and features of plaque instability. Here, we discuss the HDL antiatherogenic functions in relation to oxidative modifications and the potential of reactive dicarbonyl scavengers as a therapeutic approach for ASCVD.

Lipid metabolism reprogramming in tumor-associated macrophages and implications for therapy

The tumormicroenvironment (TME) plays a key role in tumor progression. Tumor-associated macrophages (TAMs), which are natural immune cells abundantin the TME, are mainly divided into the anti-tumor M1 subtype and pro-tumor M2 subtype. Due to the high plasticity of TAMs, the conversion of the M1 to M2 phenotype in hypoxic and hypoglycemic TME promotes cancer progression, which is closely related to lipid metabolism. Key factors of lipid metabolism in TAMs, including peroxisome proliferator-activated receptor and lipoxygenase, promote the formation of a tumor immunosuppressive microenvironment and facilitate immune escape. In addition, tumor cells promote lipid accumulation in TAMs, causing TAMs to polarize to the M2 phenotype. Moreover, other factors of lipid metabolism, such as abhydrolase domain containing 5 and fatty acid binding protein, have both promoting and inhibiting effects on tumor cells. Therefore, further research on lipid metabolism in tumors is still required. In addition, statins, as core drugs regulating cholesterol metabolism, can inhibit lipid rafts and adhesion of tumor cells, which can sensitize them to chemotherapeutic drugs. Clinical studies on simvastatin and lovastatin in a variety of tumors are underway. This article provides a comprehensive review of the role of lipid metabolism in TAMs in tumor progression, and provides new ideas for targeting lipid metabolism in tumor therapy.

Anti-malarial artesunate ameliorates atherosclerosis by modulating arterial inflammatory responses via inhibiting the NF-κB-NLRP3 inflammasome pathway

Introduction: Chronic inflammation plays a critical role in the pathogenesis of atherosclerosis (AS), and involves a complex interplay between blood components, macrophages, and arterial wall. Therefore, it is valuable in the development of targeted therapies to treat AS. Methods: AS rat model was induced by atherogenic diet plus with lipopolysaccharide (LPS) and then treated by anti-malarial artesunate (Art), a succinate derivative of artemisinin. The arterial morphology was observed after Oil red O, hematoxylin-eosin, and Masson's staining. The arterial protein level was detected by immunohistochemistry or immunofluorescence. The expression level of mRNA was determined by PCR array or real-time PCR. Results: Herein, we showed that Art possessed a dose-dependently protective effect on AS rats. In detail, Art showed a comparable inhibitory effect on arterial plaque and serum lipids compared to those of rosuvastatin (RS), and further showed a better inhibition on arterial lipid deposition and arterial remodeling comprised of arterial wall thicken and vascular collagen deposition, than those of RS. The improvement of Art on AS rats was related to inhibit arterial macrophage recruitment, and inhibit nuclear factor κB (NF-κB)-related excessive arterial inflammatory responses. Critically, Art showed significant inhibition on the NLRP3 inflammasome activation in both arterial wall and arterial macrophages, by down-regulating the expression of NOD-like receptor thermal protein domain associated protein 3 (NLRP3) and apoptosis associated speckle-like protein containing CARD (ASC), leading to less production of the NLRP3 inflammasome-derived caspase-1, interleukin-1β (IL-1β), IL-18, and subsequent transforming growth factor β1 (TGF-β1) in AS rats. Conclusion: We propose that Art is an anti-AS agent acts through modulating the arterial inflammatory responses via inhibiting the NF-κB - NLRP3 inflammasome pathway.

L-Carnitine supplementation reduces biomarkers of inflammatory and oxidative stress in patients with coronary artery disease: a randomised controlled trial

OBJECTIVE

l-Carnitine has been suggested as a potential nutrient that alleviates the oxidative and inflammatory damages of coronary artery disease (CAD), but the results of the previous studies of the importance of this supplementation remains unclear. This study attempts to evaluate the effects of l-carnitine (LC) supplementation on oxidative stress and inflammatory biomarkers in patients with CAD.

METHODS

A double-blind, randomised, placebo-trial was conducted on 75 CAD subjects. Patients were randomly assigned to receive LC (1000 mg/day) or placebo capsules over 3 months. Sera high-sensitivity C-reactive protein (hs-CRP), myeloperoxidase (MPO), nitrotyrosine (NT) and total antioxidant capacity (TAC) were assayed.

RESULTS

A significant increase in serum TAC and a significant decrease in MPO, NT, and hs-CRP levels were detected following 12 weeks of LC supplementation, compared to the placebo.

CONCLUSIONS

These results suggest that LC supplementation may exert beneficial effect on cardiovascular health through attenuate oxidative and inflammatory markers in CAD patients.

Effect of Thymoquinone on Renal Damage Induced by Hyperlipidemia in LDL Receptor-Deficient (LDL-R-/-) Mice

Hyperlipidemia is a well-established risk factor for kidney injury, which can lead to chronic kidney disease (CKD). Thymoquinone (TQ) is one of the most active ingredients in Nigella sativa seeds. It has various beneficial properties, including antioxidant and anti-inflammatory activities. TQ also exerts positive effects on doxorubicin- (DOX-) induced nephropathy and ischemia-reperfusion-induced kidney injury in rats. Therefore, in this study, we investigated the possible protective effects of TQ against kidney injury in low-density lipoprotein receptor-deficient (LDL-R^-/^-) mice. Eight-week-old male LDL-R^-/^- mice were randomly divided into the following three groups: normal diet (ND group), high-fat diet (HFD group), and HFD combined with TQ (HFD+TQ group). The mice were fed the same diet for eight weeks. After eight weeks, we performed serological analysis of the mice in all three groups. We histologically analyzed the kidney tissue and also investigated the expression of proinflammatory cytokines in the kidney tissue. Metabolic characteristics, including total cholesterol (TC), low-density lipoprotein-cholesterol (LDL-C), and creatinine (CRE) levels, were lower in the LDL-R^-/^- HFD+TQ mice than in the HFD mice. Periodic acid-Schiff (PAS) and Masson's trichrome staining revealed excessive lipid deposition and collagen accumulation in the kidneys of the LDL-R^-/^- HFD mice, which were significantly reduced in the LDL-R^-/^- HFD+TQ mice. Furthermore, macrophages and levels of proinflammatory cytokines were lower in the kidney tissues of the LDL-R^-/^- HFD+TQ mice than in those of the LDL-R^-/^- HFD mice. Moreover, profibrosis- and oxidative stress-related protein expression was lower in the kidney tissues of the LDL-R^-/^- HFD+TQ mice than in those of the LDL-R^-/^- HFD mice. These results indicate that TQ may be a potential therapeutic agent for kidney damage caused by hyperlipidemia.

Investigation of the effective components inhibited macrophage foam cell formation in Ophiopogonis Radix

ETHNOPHARMACOLOGICAL RELEVANCE

Ophiopogonis Radix, the commonly used traditional Chinese medicine in clinic for treating cardiovascular diseases, is returned to the stomach, lung and heart meridian. It is reported to nourish yin, moisten lung and is used to treat heart yin deficiency syndromes and asthenia of heart and lung, which indicated that Ophiopogonis Radix may have a protective effect on heart disorders. Atherosclerosisis is an important process in the development of cardiovascular diseases and abnormal lipid deposition induced macrophage foam cells is its crucial foundation. Our previous study showed the extract of Ophiopogonis Radix (EOR) ameliorates atherosclerosis in vitro. However, it may protect against cardiovascular diseases through inhibiting macrophage foam cell formation and its potential effective components and mechanisms are still unclear.

AIM OF THE STUDY

Our study aimed to investigate the effect of Ophiopogonis Radix on macrophage foam cell formation and its potential active constituents and mechanisms.

MATERIALS AND METHODS

Ox-LDL induced macrophage cells were employed to evaluate the effect of Ophiopogonis Radix on macrophage foam cell formation. Then the potential active constituents inhibited formation of macrophage foam cells were screened by biospecific cell extraction and its underlying mechanisms were also explored by Western blot.

RESULTS

The extract of Ophiopogonis Radix was found to significantly inhibit macrophage foam cell formation, evidenced by the decrease of TG and TC and Oil Red O staining analysis in macrophage cells, which indicated that EOR reduced the formation of macrophage foam cells. At the same time, EOR was showed to increase antioxidant capacity in macrophage cells. After treatment with EOR, two potential active components interacted with macrophage foam cells specifically were identified to inhibit macrophage foam cell formation including methylophiopogonanone A and methylophiopogonanone B. Methylophiopogonanone A was then proved to decrease the expression of CD36, Lox-1 and SREBP2, increase the expression of ABCA1 obviously, while the expression of ABCG1 and SREBP1 had no changes.

CONCLUSIONS

In our study, Ophiopogonis Radix was found to protect against atherosclerosis through suppressing ox-LDL induced macrophage foam cell formation and two potential compounds were identified by biospecific cell extraction including methylophiopogonanone A and methylophiopogonanone B. Moreover, methylophiopogonanone A was proved to inhibit foam cells through reducing uptake, synthesis and increasing efflux, which may provide guidance and reference for application of Ophiopogonis Radix and investigation of the effective components of TCMs.

Impact of Posttranslational Modification in Pathogenesis of Rheumatoid Arthritis: Focusing on Citrullination, Carbamylation, and Acetylation

Rheumatoid arthritis (RA) is caused by prolonged periodic interactions between genetic, environmental, and immunologic factors. Posttranslational modifications (PTMs) such as citrullination, carbamylation, and acetylation are correlated with the pathogenesis of RA. PTM and cell death mechanisms such as apoptosis, autophagy, NETosis, leukotoxic hypercitrullination (LTH), and necrosis are related to each other and induce autoantigenicity. Certain microbial infections, such as those caused by Porphyromonasgingivalis, Aggregatibacter actinomycetemcomitans, and Prevotella copri, can induce autoantigens in RA. Anti-modified protein antibodies (AMPA) containing anti-citrullinated protein/peptide antibodies (ACPAs), anti-carbamylated protein (anti-CarP) antibodies, and anti-acetylated protein antibodies (AAPAs) play a role in pathogenesis as well as in prediction, diagnosis, and prognosis. Interestingly, smoking is correlated with both PTMs and AMPAs in the development of RA. However, there is lack of evidence that smoking induces the generation of AMPAs.

Macrophages in Atherosclerosis, First or Second Row Players?

Macrophages represent a cell type that has been widely described in the context of atherosclerosis since the earliest studies in the 17th century. Their role has long been considered to be preponderant in the onset and aggravation of atherosclerosis, in particular by participating in the establishment of a chronic inflammatory state by the release of pro-inflammatory cytokines and by uncontrolled engorgement of lipids resulting in the formation of foam cells and later of the necrotic core. However, recent evidence from mouse models using an elegant technique of tracing vascular smooth muscle cells (VSMCs) during plaque development revealed that resident VSMCs display impressive plastic properties in response to an arterial injury, allowing them to switch into different cell types within the plaque, including mesenchymal-like cells, macrophage-like cells and osteochondrogenic-like cells. In this review, we oppose the arguments in favor or against the influence of macrophages versus VSMCs in all stages of atherosclerosis including pre-atherosclerosis, formation of lipid-rich foam cells, development of the necrotic core and the fibrous cap as well as calcification and rupture of the plaque. We also analyze the relevance of animal models for the investigation of the pathophysiological mechanisms of atherosclerosis in humans, and discuss potential therapeutic strategies targeting either VSMCs or macrophage to prevent the development of cardiovascular events. Overall, although major findings have been made from animal models, efforts are still needed to better understand and therefore prevent the development of atherosclerotic plaques in humans.

Effect of Si-Miao-Yong-An decoction on the differentiation of monocytes, macrophages, and regulatory T cells in ApoE-/- mice

ETHNOPHARMACOLOGICAL RELEVANCE

Si-Miao-Yong-An decoction (SMYAD) is a renowned traditional Chinese medicinal formula. SMYAD was originally recorded in the "Shi Shi Mi Lu", which was edited by medical scientist Chen Shi'duo during the Qing Dynasty. SMYAD has been traditionally used to treat thromboangiitis obliterans. At present, it is mainly used in clinical applications and research of cardiovascular diseases.

AIM OF THE STUDY

To explore the effects of SMYAD on the pathological changes of atherosclerosis (AS) and the differentiation of monocytes, macrophages, and regulatory T (Treg) cells in apolipoprotein E knockout (ApoE-/-) mice.

MATERIALS AND METHODS

Eight C57BL/6J mice, which were fed with normal diet for 16 weeks, were used as control group. Forty ApoE-/- mice were randomly divided into model group, atorvastatin group, SMYAD low-dose (SMYAD-LD) group, SMYAD medium-dose (SMYAD-MD) group, and SMYAD high-dose (SMYAD-HD) group. ApoE-/- mice were fed with western diet (WD) for 8 weeks, and the drugs were continuously administered for 8 weeks. The levels of serum total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol (HDL-C) were measured by the esterase method. Morphological changes of the aortic sinus in mice were observed by hematoxylin-eosin (HE) staining, the lipid infiltration of the aorta and aortic sinus were observed by oil red O staining, and the spleen index was calculated. The proportion of Ly6Chigh and Ly6Clow monocyte subsets, macrophages, and their M1 phenotype, as well as Treg cells in spleen were measured by flow cytometry. The expressions of cluster of differentiation 36 (CD36), scavenger receptor A1 (SRA1), lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1), F4/80, and fork head frame protein 3 (FOXP3) in aortic sinus were assessed by immunohistochemical staining. The serum levels of oxidized low density lipoprotein (ox-LDL), interleukin-1β (IL-1β), IL-18, transforming growth factor-β (TGF-β), and IL-10 were measured by enzyme-linked immunosorbent assays (ELISA).

RESULTS

Compared with the model group, the level of serum TC and LDL-C decreased in the SMYAD group, the pathological changes of aortic sinus decreased, and lipid infiltration of aorta and aortic sinus also decreased. These decreases were accompanied by a significant downregulation of CD36, SRA1, and LOX-1. Furthermore, the proportions of Ly6Chigh pro-inflammatory monocyte subsets, macrophages, and their M1 phenotypes in spleen decreased significantly, while the proportion of Treg cells increased. In addition, while the expression of F4/80 decreased, the expression of FOXP3 increased in the aorta sinus. The levels of serum pro-inflammatory factors IL-1β and IL-18 decreased.

CONCLUSIONS

SMYAD can improve the pathological changes associated with AS and can inhibit lipid deposition in ApoE-/- mice induced by WD diet. The likely mechanism is the inhibition of the differentiation and recruitment of monocytes and macrophages, the promotion of the differentiation and recruitment of Treg cells, as well as the reduction of the secretion of pro-inflammatory factors.

Therapeutic potential of human umbilical cord mesenchymal stem cells on aortic atherosclerotic plaque in a high-fat diet rabbit model

BACKGROUND

Atherosclerosis (AS) is a complex disease caused in part by dyslipidemia and chronic inflammation. AS is associated with serious cardiovascular disease and remains the leading cause of mortality worldwide. Mesenchymal stem cells (MSCs) have evolved as an attractive therapeutic agent in various diseases including AS. Human umbilical cord MSCs (UCSCs) have been used in cell therapy trials due to their ability to differentiate and proliferate. The present study aimed to investigate the effect of UCSCs treatment on atherosclerotic plaque formation and the progression of lesions in a high-fat diet rabbit model.

METHODS

Rabbits were fed a high-fat diet and then randomly divided into three groups: control, model, and treatment groups. Rabbits in the treatment group were injected with UCSCs (6 × 106 in 500 μL phosphate buffered saline) after 1 month of high-fat diet, once every 2 weeks, for 3 months. The model group was given PBS only. We analyzed serum biomarkers, used ultrasound and histopathology to detect arterial plaques and laser Doppler imaging to measure peripheral blood vessel blood filling, and analyzed the intestinal flora and metabolism.

RESULTS

Histological analysis showed that the aortic plaque area was significantly reduced in the treatment group. We also found a significant decrease in macrophage accumulation and apoptosis, an increase in expression of scavenger receptors CD36 and SRA1, a decrease in uptake of modified low-density protein (ox-LDL), and a decrease in levels of pro-inflammatory cytokines interleukin (IL)-6 and tumor necrosis factor (TNF)-α following UCSCs treatment. We also found that anti-inflammatory cytokines IL-10 and transforming growth factor (TGF)-β expression increased in the aorta atherosclerotic plaque of the treatment group. UCSCs treatment improved the early peripheral blood filling, reduced the serum lipid level, and inhibited inflammation progression by regulating the intestinal flora dysbiosis caused by the high-fat diet. More specifically, levels of the microbiota-dependent metabolite trimethylamine-N-oxide (TMAO) were down-regulated in the treatment group.

CONCLUSIONS

UCSCs treatment alleviated atherosclerotic plaque burden by reducing inflammation, regulating the intestinal flora and TMAO levels, and repairing the damaged endothelium.

Protective Effects of Medicinal Plant Decoctions on Macrophages in the Context of Atherosclerosis

Atherosclerosis is a hallmark of most cardiovascular diseases. The implication of macrophages in this pathology is widely documented, notably for their contribution to lipid accumulation within the arterial wall, associated with oxidative stress and inflammation processes. In order to prevent or limit the atherosclerosis damage, nutritional approaches and medicinal plant-based therapies need to be considered. In Reunion Island, medicinal plant-based beverages are traditionally used for their antioxidant, lipid-lowering and anti-inflammatory properties. The aim of our study was to assess the protective effects of eight medicinal plant decoctions in an in vitro model of RAW 264.7 murine macrophages exposed to pro-atherogenic conditions (oxidized low-density lipoproteins—ox-LDL—E. coli Lipopolysaccharides—LPS). The impact of polyphenol-rich medicinal plant decoctions on cell viability was evaluated by Neutral Red assay. Fluorescent ox-LDL uptake was assessed by flow cytometry and confocal microscopy. Activation of NF-κB was evaluated by quantification of secreted alkaline phosphatase in RAW-Blue™ macrophages. Our results show that medicinal plant decoctions limited the cytotoxicity induced by ox-LDL on macrophages. Flow cytometry analysis in macrophages demonstrated that medicinal plant decoctions from S. cumini and P. mauritianum decreased ox-LDL uptake and accumulation by more than 70%. In addition, medicinal plant decoctions also inhibited NF-κB pathway activation in the presence of pro-inflammatory concentrations of E. coli LPS. Our data suggest that medicinal plant decoctions exert protective effects on ox-LDL-induced cytotoxicity and limited macrophage lipid uptake. Moreover, herbal preparations displayed anti-inflammatory properties on macrophages that can be of interest for limiting the atherosclerotic process.

Microbiota-Mediated Immune Regulation in Atherosclerosis

There is a high level of interest in identifying metabolites of endogenously produced or dietary compounds generated by the gastrointestinal (GI) tract microbiota, and determining the functions of these metabolites in health and disease. There is a wealth of compelling evidence that the microbiota is linked with many complex chronic inflammatory diseases, including atherosclerosis. Macrophages are key target immune cells in atherosclerosis. A hallmark of atherosclerosis is the accumulation of pro-inflammatory macrophages in coronary arteries that respond to pro-atherogenic stimuli and failure of digesting lipids that contribute to foam cell formation in atherosclerotic plaques. This review illustrates the role of tryptophan-derived microbiota metabolites as an aryl hydrocarbon receptor (AhR) ligand that has immunomodulatory properties. Also, microbiota-dependent trimethylamine-N-oxide (TMAO) metabolite production is associated with a deleterious effect that promotes atherosclerosis, and metabolite indoxyl sulfate has been shown to exacerbate atherosclerosis. Our objective in this review is to discuss the role of microbiota-derived metabolites in atherosclerosis, specifically the consequences of microbiota-induced effects of innate immunity in response to atherogenic stimuli, and how specific beneficial/detrimental metabolites impact the development of atherosclerosis by regulating chronic endotoxemic and lipotoxic inflammation.

Targeting foam cell formation and macrophage polarization in atherosclerosis: The Therapeutic potential of rhubarb

Atherosclerosis, a chronic inflammatory disease associated with high morbidity and mortality, is characterized by the accumulation of foam cells in the arterial wall. It has long been acknowledged that the formation of foam cells is caused by excess lipid uptake and abnormal cholesterol metabolism function. And increasing evidence shows that inhibiting foam cell formation is a promising way to suppress the development of atherosclerotic lesions. In addition to excess foam cells accumulation, inflammation is another major contributor of atherosclerotic lesions. Recently, macrophage polarization has been demonstrated to play a vital role in the regulation of inflammatory response. Generally, macrophages mainly polarized into two phenotypes: either classically activated pro-inflammatory M1 or alternatively activated anti-inflammatory M2. And targeting macrophage polarization has been considered as a feasible approach to prevent the development of atherosclerosis. At present, the anti-atherosclerosis drugs mainly classified into two types: lipid-lowering drugs and anti-inflammatory drugs. A large part of those drugs belong to western medicine, and various side effects are unavoidable. Interestingly, in recent years, Traditional Chinese medicine has attracted growing attention because of its good efficacy and low negative effects. Rhubarb (called Da Huang in Chinese) is a famous folk medicine with a wide spectrum of pharmacological effects, such as lipid-lowering and anti-inflammatory effects. In this review, we summarized current findings about the regulatory effects of Rhubarb on foam cell formation and macrophage polarization, with emphasis on the molecular mechanisms of action that have been revealed during the past two decades, to better understand its pivotal role in the treatment and prevention of atherosclerosis.

PM2.5 aggravates the lipid accumulation, mitochondrial damage and apoptosis in macrophage foam cells

Epidemiological evidence showed that the particulate matter exposure is associated with atherosclerotic plaque progression, which may be related to foam cell formation, but the mechanism is still unknown. The study was aimed to investigate the toxic effects and possible mechanism of PM_2.5 on the formation of macrophage foam cells induced by oxidized low density lipoprotein (ox-LDL). Results showed that PM_2.5 induced cytotoxicity by decreasing the cell viability and increasing the LDH level in macrophage foam cells. PM_2.5 aggravated the lipid accumulation in ox-LDL-stimulated macrophage RAW264.7 within markedly increasing level of intracellular lipid by Oil red O staining. The level of ROS increased obivously after co-exposure to PM_2.5 and ox-LDL than single exposure group. In addition, serious mitochondrial damage such as the mitochondrial swelling, cristae rupturing and disappearance were observed in macrophage foam cells. The loss of the mitochondrial membrane potential (MMP) further exacerbated the mitochondrial damage in PM_2.5-induced macrophage foam cells. The apoptotic rate increased more severely via up-regulated protein level of Bax, Cyt C, Caspase-9, Caspase-3, and down-regulated that of Bcl-2, indicating that PM_2.5 activated the mitochondrial-mediated apoptosis pathway. In summary, our results demonstrated that PM_2.5 aggravated the lipid accumulation, mitochondrial damage and apoptosis in macrophage foam cells, suggesting that PM_2.5 was a risk factor of atherosclerosis progression.

Macrophages and Their Role in Destabilization of an Atherosclerotic Plaque

The modern data on structure and the functional activity of macrophages are presented in the review. It is shown that they are the nonhomogeneous cell population. Two of their main subpopulations are presented as M1 and M2 phenotypes which perform opposite functions at inflammation development. The main attention in the review is paid to a role of macrophages in pathogenesis of atherosclerosis and, first, in formation of unstable atherosclerotic plaques which are the cause of the most severe complications of the disease. It is shown that main subpopulations of macrophages play different roles in formation of unstable and stable atherosclerotic plaques. Macrophages of M1 phenotype in the vascular wall carry out pro-atherogenic role and influence destabilization of an atherosclerotic plaque, while M2 macrophages perform atheroprotective function.

Study on the levels of glycosylated lipoprotein in patients with coronary artery atherosclerosis

BACKGROUND

The main risk factors for atherosclerosis patients are not fully explicated. The aim of this study was to analyze the levels of blood lipid and glycosylated lipoprotein in patients with coronary artery atherosclerosis and healthy individuals and to study the relationship between the glycosylated lipoprotein and atherosclerosis.

METHODS

The study involved 200 patients diagnosed with myocardial infarction caused by coronary atherosclerosis as case group and 230 healthy individuals as control group. We analyzed and contrasted the levels of blood lipid and glycosylated lipoprotein between the different groups. In addition, we investigated the correlation between glycosylated low-density lipoprotein (G-LDL) and glucose levels.

RESULTS

There is no statistical difference between the level of TG in case group and control group. The level of CHOL, HDL-C, and LDL-C in case group is significantly lower than that in control group (3.90 [3.23, 4.42] vs 5.16 [4.86, 5.77] [mmol/L]; 1.09 [0.83, 1.38] vs 1.46 [1.15, 1.80] [mmol/L]; 2.22 [1.68, 2.81] vs 2.95 [2.60, 3.27] [mmol/L]) (P < 0.05). The level of GLU, HbA1c, G-HDL, and G-LDL in case group is significantly higher than that in control group (7.10 [5.68, 9.27] vs 4.84 [4.68, 5.07] [mmol/L]; 6.8 [6.3, 7.4] vs 5.9 [5.6, 6.1] [%]; 30.08 [25.04, 40.17] vs 22.95 [18.14, 27.06] [ng/mL], 6.26 [4.95, 7.50] vs 3.61 [2.66, 5.15] [ng/mL]) (p < 0.05). The level of G-LDL in patients with coronary atherosclerosis was relevant with the level of GLU and HbA1c (r = 0.625, 0.706, P < 0.05), and there was no relevance with LDL-C (r = 0.331, P > 0.05).

CONCLUSION

Hyperlipidemia is not an important cause of coronary atherosclerosis. High glucose levels and glycosylated lipoprotein are of high importance in the development and progression of coronary atherosclerosis.

Linkage of Infection to Adverse Systemic Complications: Periodontal Disease, Toll-Like Receptors, and Other Pattern Recognition Systems

Toll-like receptors (TLRs) are a group of pattern recognition receptors (PRRs) that provide innate immune sensing of conserved pathogen-associated molecular patterns (PAMPs) to engage early immune recognition of bacteria, viruses, and protozoa. Furthermore, TLRs provide a conduit for initiation of non-infectious inflammation following the sensing of danger-associated molecular patterns (DAMPs) generated as a consequence of cellular injury. Due to their essential role as DAMP and PAMP sensors, TLR signaling also contributes importantly to several systemic diseases including cardiovascular disease, diabetes, and others. The overlapping participation of TLRs in the control of infection, and pathogenesis of systemic diseases, has served as a starting point for research delving into the poorly defined area of infection leading to increased risk of various systemic diseases. Although conflicting studies exist, cardiovascular disease, diabetes, cancer, rheumatoid arthritis, and obesity/metabolic dysfunction have been associated with differing degrees of strength to infectious diseases. Here we will discuss elements of these connections focusing on the contributions of TLR signaling as a consequence of bacterial exposure in the context of the oral infections leading to periodontal disease, and associations with metabolic diseases including atherosclerosis and type 2 diabetes.

The role of monocytosis and neutrophilia in atherosclerosis

Monocytosis and neutrophilia are frequent events in atherosclerosis. These phenomena arise from the increased proliferation of hematopoietic stem and multipotential progenitor cells (HSPCs) and HSPC mobilization from the bone marrow to other immune organs and circulation. High cholesterol and inflammatory signals promote HSPC proliferation and preferential differentiation to the myeloid precursors (i.e., myelopoiesis) that than give rise to pro-inflammatory immune cells. These cells accumulate in the plaques thereby enhancing vascular inflammation and contributing to further lesion progression. Studies in animal models of atherosclerosis showed that manipulation with HSPC proliferation and differentiation through the activation of LXR-dependent mechanisms and restoration of cholesterol efflux may have a significant therapeutic potential.

Protein Carbamylation: Chemistry, Pathophysiological Involvement, and Biomarkers

Protein carbamylation refers to a nonenzymatic modification, which consists in the binding of isocyanic acid on protein functional groups. This reaction is responsible for the alteration in structural and functional properties of proteins, which participate in their molecular aging. Protein molecular aging is now considered a molecular substratum for the development of chronic and inflammatory diseases, including atherosclerosis, chronic kidney disease, or rheumatoid arthritis. As a consequence, carbamylation-derived products have been proposed as interesting biomarkers in various pathological contexts and appropriate analytical methods have been developed for their quantification in biological fluids. The purpose of this review is (i) to describe the biochemical bases of the carbamylation reaction, (ii) to explain how it contributes to protein molecular aging, (iii) to provide evidence of its involvement in aging and chronic diseases, and (iv) to list the available biomarkers of carbamylation process and the related analytical methods.

Tofacitinib ameliorates atherosclerosis and reduces foam cell formation in apoE deficient mice

Atherosclerosis is a chronic inflammatory cardiovascular disease with high mortality worldwide. Tofacitinib (CP-690,550), an oral small-molecule Janus kinase inhibitor, has been shown to be effective in the treatment of rheumatoid arthritis, autoimmune encephalomyelitis and ulcerative colitis. However, its protective effect against atherosclerosis remains poorly understood. The aim of the present study was to evaluate the effects of Tofacitinib on atherogenic diet (ATD)-induced atherosclerosis using apolipoprotein E deficient (apoE-/-) mice. Atherosclerosis-prone apoE-/- mice were fed with ATD and treated with or without Tofacitinib through intragastrical administration (10 mg kg^-1 day^-1) for 8 weeks. Our results showed that Tofacitinib did not change plasma lipids, while significantly reduced the levels of plasma pro-inflammatory cytokines IL-6 and TNF-α. It also significantly attenuated atherosclerotic plaque lesion in the aortic root and macrophages contained in plaque as shown with Mac2 immuno-staining. Peritoneal macrophages (PMC) were separated from apoE-/- mice fed with 8-week ATD, and then subjected to inflammation tests. Flow cytometry analysis of F4/80 and CD206 and mRNA levels of M1 and M2 macrophages markers showed that M1 macrophages decreased while M2 macrophages increased in Tofacitinib treated group. Expressions of other inflammatory genes also indicated an anti-inflammatory status in mice treated with Tofacitinib. Ox-LDL was used to induce foam cell formation from PMC in wild type mice, and the results displayed a reduced formation of foam cells and decreased inflammation in mice with Tofacitinib administration (1 μM). The mRNA and protein levels of ATP binding cassette subfamily A member 1 (ABCA1), a key gene involved in cholesterol efflux, remarkably increased, while it was absence of alterations in scavenger receptors expression. Therefore, we demonstrated that Tofacitinib could attenuate atherosclerosis and foam cells formation by inhibiting inflammation and upregulating ABCA1 expression.