Macrophages in vascular inflammation--From atherosclerosis to vasculitis

Molecular fingerprints of cardiovascular toxicities of immune checkpoint inhibitors

Immune checkpoint inhibitors (ICIs) have revolutionized cancer therapy by unleashing the power of the immune system against malignant cells. However, their use is associated with a spectrum of adverse effects, including cardiovascular complications, which can pose significant clinical challenges. Several mechanisms contribute to cardiovascular toxicity associated with ICIs. First, the dysregulation of immune checkpoints, such as cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) and programmed cell death protein-1 (PD-1) and its ligand (PD-L1), and molecular mimicry with cardiac autoantigens, leads to immune-related adverse events, including myocarditis and vasculitis. These events result from the aberrant activation of T cells against self-antigens within the myocardium or vascular endothelium. Second, the disruption of immune homeostasis by ICIs can lead to autoimmune-mediated inflammation of cardiac tissues, manifesting as cardiac dysfunction and heart failure, arrhythmias, or pericarditis. Furthermore, the upregulation of inflammatory cytokines, particularly tumor necrosis factor-alpha, interferon-γ, interleukin-1β, interleukin-6, and interleukin-17 contributes to cardiac and endothelial dysfunction, plaque destabilization, and thrombosis, exacerbating cardiovascular risk on the long term. Understanding the intricate mechanisms of cardiovascular side effects induced by ICIs is crucial for optimizing patient care and to ensure the safe and effective integration of immunotherapy into a broader range of cancer treatment protocols. The clinical implications of these mechanisms underscore the importance of vigilant monitoring and early detection of cardiovascular toxicity in patients receiving ICIs. Future use of these key pathological mediators as biomarkers may aid in prompt diagnosis of cardiotoxicity and will allow timely interventions.

Ultrasound Examination of Common Carotid Adventitial Thickness Can Differentiate Takayasu Arteritis and Large Vessel Giant Cell Arteritis

Pathological studies have demonstrated that the adventitial layer is markedly thickened in Takayasu (TAK) as compared to large vessel giant cell arteritis (LV-GCA). An ultrasound (US) examination of the arterial vessels allows the determination of intima media thickness (IMT) and of adventitial layer thickness (extra media thickness (EMT)). No previous study has evaluated if there are differences in EMT thickness between TAK and LV-GCA. In this cross-sectional retrospective study of stored ultrasound (US) imaging, we have compared common carotid artery (CCA) EMT and IMT in a series of consecutive TAK and LV-GCA patients. US examination CCA IMT and EMT were significantly higher in TAK as compared to LV-GCA. With ROC curve analysis, we have found that an EMT > 0.76 mm has high sensitivity and specificity for TAK CCA examination. The percentage of CCA at EMT > 0.76 mm and the total arterial wall thickening were significantly higher in TAK group examinations. EMT thickness correlated with disease duration and IMT in the TAK group, as well as with the IMT and ESR values in the LV-GCA group. Upon multivariate logistic regression analysis, factors independently associated with TAK CCA were EMT > 0.76 mm and age. No significant variation in IMT and EMT could be demonstrated in subsequent US CCA examinations.

Enhanced Anti-Inflammatory Activity of Tilianin Based on the Novel Amorphous Nanocrystals

Tilianin (Til), a flavonoid glycoside, is well-known for its therapeutic promise in treating inflammatory disorders. Its poor water solubility and permeability limit its clinical applicability. In order to overcome these restrictions, an antisolvent precipitation and ultrasonication technique was used to prepare amorphous tilianin nanocrystals (Til NCs). We have adjusted the organic solvents, oil-to-water ratio, stabilizer composition, and ultrasonic power and time by combining single-factor and central composite design (CCD) methodologies. The features of Til NCs were characterized using powder X-ray diffraction (PXRD), scanning calorimetry (DSC), and transmission electron microscopy (TEM). Specifically, the optimized Til NCs were needle-like with a particle size ranging from 90 to 130 nm. PVA (0.3%, w/v) and TPGS (0.08%, w/v) stabilized them well. For at least two months, these Til NCs stayed amorphous and showed an impressive stability at 4 °C and 25 °C. Remarkably, Til NCs dissolved almost 20 times faster in simulated intestinal fluid (SIF) than they did in crude Til. In RAW264.7 cells, Til NCs also showed a better cellular absorption as well as safety and protective qualities. Til NCs were shown to drastically lower reactive oxygen species (ROS), TNF-α, IL-1β, and IL-6 in anti-inflammatory experiments, while increasing IL-10 levels and encouraging M1 macrophages to adopt the anti-inflammatory M2 phenotype. Our results highlight the potential of amorphous Til NCs as a viable approach to improve Til's anti-inflammatory effectiveness, solubility, and dissolving rate.

Molecular Pathways of Vulnerable Carotid Plaques at Risk of Ischemic Stroke: A Narrative Review

The concept of vulnerable carotid plaques is pivotal in understanding the pathophysiology of ischemic stroke secondary to large-artery atherosclerosis. In macroscopic evaluation, vulnerable plaques are characterized by one or more of the following features: microcalcification; neovascularization; lipid-rich necrotic cores (LRNCs); intraplaque hemorrhage (IPH); thin fibrous caps; plaque surface ulceration; huge dimensions, suggesting stenosis; and plaque rupture. Recognizing these macroscopic characteristics is crucial for estimating the risk of cerebrovascular events, also in the case of non-significant (less than 50%) stenosis. Inflammatory biomarkers, such as cytokines and adhesion molecules, lipid-related markers like oxidized low-density lipoprotein (LDL), and proteolytic enzymes capable of degrading extracellular matrix components are among the key molecules that are scrutinized for their associative roles in plaque instability. Through their quantification and evaluation, these biomarkers reveal intricate molecular cross-talk governing plaque inflammation, rupture potential, and thrombogenicity. The current evidence demonstrates that plaque vulnerability phenotypes are multiple and heterogeneous and are associated with many highly complex molecular pathways that determine the activation of an immune-mediated cascade that culminates in thromboinflammation. This narrative review provides a comprehensive analysis of the current knowledge on molecular biomarkers expressed by symptomatic carotid plaques. It explores the association of these biomarkers with the structural and compositional attributes that characterize vulnerable plaques.

Impact of subcutaneous belimumab on disease activity, patient satisfaction, and metabolic profile in long-lasting systemic lupus erythematosus

OBJECTIVE

Atherosclerosis is a major complication of systemic lupus erythematosus (SLE) and is exacerbated by the disease itself, drug toxicity, and metabolic syndrome. Although belimumab (BEL) can ameliorate disease activity and reduce prednisolone (PSL) dose in SLE, its effect on metabolic profiles is obscure. We aimed to assess the effects of subcutaneous BEL on disease activity and metabolic profiles.

METHODS

A total of 106 patients with SLE who received subcutaneous BEL were included, and 76 patients who started BEL treatment at least 1 year prior were evaluated. Clinical information, including retention rate, disease activity, renal outcome, patient satisfaction, and metabolic profiles, were retrospectively analysed.

RESULTS

The retention rate of BEL was > 80% after 2 years, and ineffectiveness and pain were the major reasons for discontinuation of BEL treatment. Satisfaction with side effects was higher in the BEL group than that in the PSL group. Belimumab significantly improved disease activity, lupus nephritis, and PSL dosage, with a median reduction of 4 mg/day. These effects were observed in active disease and positive C1q-binding immune complex, and PSL reduction ≥ 5 mg was achievable in such cases. Patients with PSL reduction of ≥ 5 mg showed significantly lower blood low-density lipoprotein and triglyceride by 13 and 17 mg/dL, respectively, while those with PSL reduction of < 5 mg remained unaltered.

CONCLUSION

Subcutaneous BEL was effective in improving disease activity and proteinuria in patients with chronic disease while reducing PSL. Reduction in PSL by BEL also improved lipid status, which could synergistically reduce cardiovascular risk in SLE. Key Points • Significant reduction of disease activity, proteinuria, and prednisolone was observed in patients using subcutaneous belimumab. • Patient satisfaction was higher in terms of side effects in subcutaneous belimumab compared with prednisolone. • Reduction in prednisolone by belimumab contributed to the improvement of lipid status and would reduce the cardiovascular risk.

Proinflammatory signaling mechanism of endocan in macrophages: Involvement of TLR2 mediated MAPK-NFkB pathways

Endocan is an endothelial cell-specific proteoglycan that contributes to vascular dysfunction by impairing endothelial function and inducing vascular smooth muscle cell migration. However, its role in regulating macrophage inflammation, a key pathological feature of vascular dysfunction, is not well understood. In this study, we investigated the effect of endocan on macrophage inflammation to better understand its contribution to vascular dysfunction. We found that endocan upregulated pro-inflammatory cytokines including IL-1β, IL-6 and TNF-α in RAW 264.7 cells and activated MAPK/NFkB signaling pathways. Inhibiting these pathways reduced endocan-induced cytokine levels, while inhibiting TLR2 compromised the MAPK/NFkB regulation. Additionally, LPS-induced HUVEC conditioned medium stimulated cytokine levels in RAW 264.7 cells, which were reduced by endocan siRNA treatment in HUVEC. These results suggest that endocan positively regulates pro-inflammation in macrophages through the TLR2-MAPK-NFkB axis, highlighting the potential of targeting endocan to reduce inflammation in vascular dysfunction.

Embedded macrophages induce intravascular coagulation in 3D blood vessel-on-chip

Macrophages are innate immune cells that prevent infections and help in wound healing and vascular inflammation. While these cells are natural helper cells, they also contribute to chronic diseases, e.g., by infiltrating the endothelial layer in early atherosclerosis and by promoting vascular inflammation. There is a crosstalk between inflammatory pathways and key players in thrombosis, such as platelets and endothelial cells - a phenomenon known as 'thromboinflammation'. The role of the embedded macrophages in thromboinflammation in the context of vascular disease is incompletely understood. Blood vessels-on-chips, which are microfluidic vascular cell culture models, have been used extensively to study aspects of vascular disease, like permeability, immune cell adhesion and thrombosis. Blood perfusion assays in blood vessel-on-chip models benefit from multiple unique aspects of the models, such as control of microvessel structure and well-defined flow patterns, as well as the ability to perform live imaging. However, due to their simplified nature, blood vessels-on-chip models have not yet been used to capture the complex cellular crosstalk that is important in thromboinflammation. Using induced pluripotent stem cell-derived endothelial cells and polarized THP-1 monocytes, we have developed and systematically set up a 3D blood vessel-on-chip with embedded (lipid-laden) macrophages, which is created using sequential cell seeding in viscous finger patterned collagen hydrogels. We have set up a human whole blood perfusion assay for these 3D blood vessels-on-chip. An increased deposition of fibrin in the blood vessel-on-chip models containing lipid-laden macrophages was observed. We anticipate the future use of this advanced vascular in vitro model in drug development for early atherosclerosis or aspects of other vascular diseases.

Olive mill wastewater and hydroxytyrosol inhibits atherogenesis in apolipoprotein E-deficient mice

The Mediterranean diet, which is characterized by high consumption of olive oil, prevents cardiovascular disease. Meanwhile, olive mill wastewater (OMWW), which is obtained as a byproduct during olive oil production, contains various promising bioactive components such as water-soluble polyphenols. Hydroxytyrosol (HT), the major polyphenol in OMWW, has anti-oxidative and anti-inflammatory properties; however, the atheroprotective effects of OMWW and HT remain to be fully understood. Here, we investigated the effect of OMWW and HT on atherogenesis. Male 8-week-old apolipoprotein E-deficient mice were fed a western-type diet supplemented with OMWW (0.30%w/w) or HT (0.02%w/w) for 20 weeks. The control group was fed a non-supplemented diet. OMWW and HT attenuated the development of atherosclerosis in the aortic arch as determined by Sudan IV staining (P < 0.01, respectively) without alteration of body weight, plasma lipid levels, and blood pressure. OMWW and HT also decreased the production of oxidative stress (P < 0.01, respectively) and the expression of NADPH oxidase subunits (e.g., NOX2 and p22phox) and inflammatory molecules (e.g. IL-1β and MCP-1) in the aorta. The results of in vitro experiments demonstrated that HT inhibited the expression of these molecules that were stimulated with LPS in RAW264.7 cells, murine macrophage-like cells. OMWW and HT similarly attenuated atherogenesis. HT is a major component of water-soluble polyphenols in OMWW, and it inhibited inflammatory activation of macrophages. Therefore, our results suggest that the atheroprotective effects of OMWW are at least partially attributable to the anti-inflammatory effects of HT.

Immune landscape and redox imbalance during neurological disorders in COVID-19

The outbreak of Coronavirus Disease 2019 (COVID-19) has prompted the scientific community to explore potential treatments or vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus that causes the illness. While SARS-CoV-2 is mostly considered a respiratory pathogen, several neurological complications have been reported, raising questions about how it may enter the Central Nervous System (CNS). Receptors such as ACE2, CD147, TMPRSS2, and NRP1 have been identified in brain cells and may be involved in facilitating SARS-CoV-2 entry into the CNS. Moreover, proteins like P2X7 and Panx-1 may contribute to the pathogenesis of COVID-19. Additionally, the role of the immune system in the gravity of COVID-19 has been investigated with respect to both innate and adaptive immune responses caused by SARS-CoV-2 infection, which can lead to a cytokine storm, tissue damage, and neurological manifestations. A redox imbalance has also been linked to the pathogenesis of COVID-19, potentially causing mitochondrial dysfunction, and generating proinflammatory cytokines. This review summarizes different mechanisms of reactive oxygen species and neuro-inflammation that may contribute to the development of severe COVID-19, and recent progress in the study of immunological events and redox imbalance in neurological complications of COVID-19, and the role of bioinformatics in the study of neurological implications of COVID-19.

Traditional and Disease-Specific Risk Factors for Cardiovascular Events in Antineutrophil Cytoplasmic Antibody-Associated Vasculitis: A Multinational Retrospective Study

OBJECTIVE

To investigate the occurrence of cardiovascular events (CVEs) in a large cohort of patients with antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) across the European Union, China, Turkey, Russia, the United Kingdom, and the USA.

METHODS

Patients with a definite diagnosis of AAV who were followed for ≥ 3 months and had sufficient documentation were included. Data on myocardial infarction (MI) and stroke were collected retrospectively from tertiary vasculitis centers. Univariate and multivariate Cox regression models were used to estimate hazard ratios (HRs) and 95% CIs.

RESULTS

Over a median follow-up of 62.0 months (IQR 22.6-100.0), CVEs (mostly MIs) occurred in 245 (10.7%) of 2286 patients with AAV, with a higher frequency in China and the UK. On multivariate regression analysis, older age (55-64.9 yrs, HR 2.93, 95% CI 1.99-4.31), smoking (HR 1.98, 95% CI 1.48-2.64), Chinese origin (HR 4.24, 95% CI 3.07-5.85), and pulmonary (HR 1.50, 95% CI 1.09-2.06) and kidney (HR 3.02, 95% CI 2.08-4.37) involvement were independent variables associated with a higher occurrence of CVEs.

CONCLUSION

We showed that geographic region and both traditional and disease-specific (kidney involvement in particular) factors were independently associated with CVEs. Proper assessment and management of modifiable cardiovascular (CV) risk factors are essential for prevention of CV morbidity in patients with AAV.

The activation of CaN/NFAT signaling pathway in macrophages aggravated Lactobacillus casei cell wall extract-induced Kawasaki disease vasculitis

OBJECTIVES

By using GWAS(genome-wide association studies) and linkage disequilibrium analysis to investigate the susceptibility genes of KD(Kawasaki disease), previous studies have identified that the CaN(calcineurin)-NFAT(the nuclear factor of activated T cell) signal pathway were significantly associated with susceptibility to KD. However, little is known about the molecular basis of the CaN/NFAT pathway involved in KD. Therefore, in our study we investigate the role of Ca2+/CaN/NFAT signaling pathway in macrophages in vitro and in vivo on coronary artery lesions induced by LCWE (Lactobacillus casei cell wall extract).

METHODS AND RESULTS

We observed that LCWE could increase the expression of NFAT1 and NFAT2 in macrophages in vitro, and also enhance the transcriptional activity of NFAT by promoting the nucleus translocation. Similarly, in LCWE-induced mice model, the expression of NFAT1 and NFAT2 and associated proinflammatory factors were increased significantly. In addition, by knocking down or overexpressing NFAT1 or NFAT2 in macrophages, the results indicated that NFAT signaling pathway mediated LCWE-induced immune responses in macrophages and regulated the synthesis of IL(interleukin)-6, IL-1β and TNF(tumor necrosis factor)-α in LCWE-induced macrophage activation. As well, we found that this process could be suppressed by CaN inhibitor CsA(cyclosporinA).

CONCLUSIONS

Therefore, the CaN/NFAT signaling pathway mediated LCWE-induced immune responses in macrophages, and also participated in the LCWE-induced CALs(coronary artery lesions). And also the inhibitory effect of CsA in LCWE-induced cell model towards a strategy to modulate the CaN/NFAT pathway during the acute course of KD might be helpful in alleviate KD-induced CALs.

Micro- and Macrovascular Effects of Inflammation in Peripheral Artery Disease-Pathophysiology and Translational Therapeutic Approaches

Inflammation has a critical role in the development and progression of atherosclerosis. On the molecular level, inflammatory pathways negatively impact endothelial barrier properties and thus, tissue homeostasis. Conformational changes and destruction of the glycocalyx further promote pro-inflammatory pathways also contributing to pro-coagulability and a prothrombotic state. In addition, changes in the extracellular matrix composition lead to (peri-)vascular remodelling and alterations of the vessel wall, e.g., aneurysm formation. Moreover, progressive fibrosis leads to reduced tissue perfusion due to loss of functional capillaries. The present review aims at discussing the molecular and clinical effects of inflammatory processes on the micro- and macrovasculature with a focus on peripheral artery disease.

Common Autoantibody among Takayasu Arteritis and Ulcerative Colitis: A Possible Pathophysiology That Includes Gut-Vessel Connection in Vascular Inflammation

Takayasu arteritis (TAK) is a type of large-vessel vasculitis that predominantly affects young females. The precise pathomechanism of TAK is still under investigation. In TAK, the vasa vasorum is considered to be the initial inflammatory site. Disruption of the vasa vasorum induces the entry of inflammatory cells into the vascular wall of large vessels between the media and adventitia, and infiltrated cells damage the vascular components, eventually leading to stenosis or dilatation of the affected arteries. In addition, T cells are considered key players in TAK, and myeloid cells function as effector cells. Although the roles of B cells in TAK are poorly understood, recent evidence supports their contribution to the pathogenicity of TAK. Particularly, two autoantibodies have been identified in TAK through investigation of anti-endothelial cell antibodies, and they could be involved in the maintenance of vascular inflammation. Furthermore, one of the autoantibodies, anti-endothelial protein C receptor, was shown to be present in ulcerative colitis (UC), which is genetically and clinically associated with TAK. Similar autoantibodies in inflammatory diseases with different target organs indicate a common underlying pathophysiology of these diseases, which could be characterized by the aberrant activation of B cells. This review discusses recent understanding of the pathomechanisms of TAK and UC, with a focus on the involvement of B cells and autoantibodies. The close association of UC with TAK further suggests a common etiology, and the importance of the intestinal microbiota, including dysbiosis, is also becoming known in TAK. Investigation of such common factors among TAK and UC would improve understanding of the interplay between gut and vascular inflammation, which is a new concept for developing vascular inflammation through the gut-vessel connection.

Diversity of cells and signals in the cardiovascular system

This white paper is the outcome of the seventh UC Davis Cardiovascular Research Symposium on Systems Approach to Understanding Cardiovascular Disease and Arrhythmia. This biannual meeting aims to bring together leading experts in subfields of cardiovascular biomedicine to focus on topics of importance to the field. The theme of the 2022 Symposium was 'Cell Diversity in the Cardiovascular System, cell-autonomous and cell-cell signalling'. Experts in the field contributed their experimental and mathematical modelling perspectives and discussed emerging questions, controversies, and challenges in examining cell and signal diversity, co-ordination and interrelationships involved in cardiovascular function. This paper originates from the topics of formal presentations and informal discussions from the Symposium, which aimed to develop a holistic view of how the multiple cell types in the cardiovascular system integrate to influence cardiovascular function, disease progression and therapeutic strategies. The first section describes the major cell types (e.g. cardiomyocytes, vascular smooth muscle and endothelial cells, fibroblasts, neurons, immune cells, etc.) and the signals involved in cardiovascular function. The second section emphasizes the complexity at the subcellular, cellular and system levels in the context of cardiovascular development, ageing and disease. Finally, the third section surveys the technological innovations that allow the interrogation of this diversity and advancing our understanding of the integrated cardiovascular function and dysfunction.

The interplay between microbial metabolites and macrophages in cardiovascular diseases: A comprehensive review

The gut microbiome has emerged as a crucial player in developing and progressing cardiovascular diseases (CVDs). Recent studies have highlighted the role of microbial metabolites in modulating immune cell function and their impact on CVD. Macrophages, which have a significant function in the pathogenesis of CVD, are very vulnerable to the effects of microbial metabolites. Microbial metabolites, such as short-chain fatty acids (SCFAs) and trimethylamine-N-oxide (TMAO), have been linked to atherosclerosis and the regulation of immune functions. Butyrate has been demonstrated to reduce monocyte migration and inhibit monocyte attachment to injured endothelial cells, potentially contributing to the attenuation of the inflammatory response and the progression of atherosclerosis. On the other hand, TMAO, another compound generated by gut bacteria, has been linked to atherosclerosis due to its impact on lipid metabolism and the accumulation of cholesterol in macrophages. Indole-3-propionic acid, a tryptophan metabolite produced solely by microbes, has been found to promote the development of atherosclerosis by stimulating macrophage reverse cholesterol transport (RCT) and raising the expression of ABCA1. This review comprehensively discusses how various microbiota-produced metabolites affect macrophage polarization, inflammation, and foam cell formation in CVD. We also highlight the mechanisms underlying these effects and the potential therapeutic applications of targeting microbial metabolites in treating CVD.

Adventitial macrophage accumulation impairs perivascular nerve function in mesenteric arteries with inflammatory bowel disease

Introduction: Inflammatory bowel disease involves aberrant immune responses and is associated with both cardiovascular disease risk and altered intestinal blood flow. However, little is known about how inflammatory bowel disease affects regulation of perivascular nerves that mediate blood flow. Previous work found perivascular nerve function is impaired in mesenteric arteries with Inflammatory bowel disease. The purpose of this study was to determine the mechanism of impaired perivascular nerve function. Methods: RNA sequencing was performed on mesenteric arteries from IL10^-/- mice treated with H. hepaticus to induce disease (inflammatory bowel disease) or left non-gavaged (Control). For all other studies, Control and Inflammatory bowel disease mice received either saline or clodronate liposome injections to study the effect of macrophage depletion. Perivascular nerve function was assessed using pressure myography and electrical field stimulation. Leukocyte populations, and perivascular nerves, and adventitial neurotransmitter receptors were labeled using fluorescent immunolabeling. Results: Inflammatory bowel disease was associated with increases in macrophage-associated gene expression, and immunolabeling showed accumulation of adventitial macrophages. Clodronate liposome injection eliminated adventitial macrophages, which reversed significant attenuation of sensory vasodilation, sympathetic vasoconstriction and sensory inhibition of sympathetic constriction in inflammatory bowel disease. Acetylcholine-mediated dilation was impaired in inflammatory bowel disease and restored after macrophage depletion, but sensory dilation remained nitric oxide independent regardless of disease and/or macrophage presence. Conclusion: Altered neuro-immune signaling between macrophages and perivascular nerves in the arterial adventitia contributes to impaired vasodilation, particularly via dilatory sensory nerves. Targeting the adventitial macrophage population may help preserve intestinal blood flow in Inflammatory bowel disease patients.

Adventitial macrophage accumulation impairs perivascular nerve function in mesenteric arteries with inflammatory bowel disease

Introduction

Inflammatory bowel disease (IBD) involves aberrant immune responses and is associated with both cardiovascular disease risk and altered intestinal blood flow. However, little is known about how IBD affects regulation of perivascular nerves that mediate blood flow. Previous work found perivascular nerve function is impaired in mesenteric arteries with IBD. The purpose of this study was to determine the mechanism of impaired perivascular nerve function.

Methods

RNA sequencing was performed on mesenteric arteries from IL10 ^-/- mice treated with H.hepaticus to induce disease (IBD) or left non-gavaged (Control). For all other studies, Control and IBD mice received either saline or clodronate liposome injections to study the effect of macrophage depletion. Perivascular nerve function was assessed using pressure myography and electrical field stimulation. Fluorescent immunolabeling was used to label leukocyte populations and perivascular nerves.

Results

IBD was associated with increased in macrophage-associated gene expression, and immunolabeling showed accumulation of adventitial macrophages. Clodronate liposome injection eliminated adventitial macrophages, which reversed significant attenuation of sensory vasodilation, sympathetic vasoconstriction and sensory inhibition of sympathetic constriction in IBD. Acetylcholine-mediated dilation was impaired in IBD and restored after macrophage depletion, but sensory dilation remained nitric oxide independent regardless of disease and/or macrophage presence.

Conclusion

Altered neuro-immune signaling between macrophages and perivascular nerves in the arterial adventitia contributes to impaired vasodilation, particularly via dilatory sensory nerves. Targeting the adventitial macrophage population may help preserve intestinal blood flow in IBD patients.

Mitochondria as disease-relevant organelles in rheumatoid arthritis

Mitochondria are the controllers of cell metabolism and are recognized as decision makers in cell death pathways, organizers of cytoplasmic signaling networks, managers of cellular stress responses, and regulators of nuclear gene expression. Cells of the immune system are particularly dependent on mitochondrial resources, as they must swiftly respond to danger signals with activation, trafficking, migration, and generation of daughter cells. Analogously, faulty immune responses that lead to autoimmunity and tissue inflammation rely on mitochondria to supply energy, cell building blocks and metabolic intermediates. Emerging data endorse the concept that mitochondrial fitness, and the lack of it, is of particular relevance in the autoimmune disease rheumatoid arthritis (RA) where deviations of bioenergetic and biosynthetic flux affect T cells during early and late stages of disease. During early stages of RA, mitochondrial deficiency allows naïve RA T cells to lose self-tolerance, biasing fundamental choices of the immune system toward immune-mediated tissue damage and away from host protection. During late stages of RA, mitochondrial abnormalities shape the response patterns of RA effector T cells engaged in the inflammatory lesions, enabling chronicity of tissue damage and tissue remodeling. In the inflamed joint, autoreactive T cells partner with metabolically reprogrammed tissue macrophages that specialize in antigen-presentation and survive by adapting to the glucose-deplete tissue microenvironment. Here, we summarize recent data on dysfunctional mitochondria and mitochondria-derived signals relevant in the RA disease process that offer novel opportunities to deter autoimmune tissue inflammation by metabolic interference.

Quantitative Proteomic Analysis Reveals the Mechanisms of Sinapine Alleviate Macrophage Foaming

Rapeseed polyphenols have cardiovascular protective effects. Sinapine, one main rapeseed polyphenol, possesses antioxidative, anti-inflammatory, and antitumor properties. However, no research has been published about the role of sinapine in alleviating macrophage foaming. This study aimed to reveal the macrophage foaming alleviation mechanism of sinapine by applying quantitative proteomics and bioinformatics analyses. A new approach was developed to retrieve sinapine from rapeseed meals by using hot-alcohol-reflux-assisted sonication combined with anti-solvent precipitation. The sinapine yield of the new approach was significantly higher than in traditional methods. Proteomics was performed to investigate the effects of sinapine on foam cells, and it showed that sinapine can alleviate foam cell formation. Moreover, sinapine suppressed CD36 expression, enhanced the CDC42 expression, and activated the JAK2 and the STAT3 in the foam cells. These findings suggest that the action of sinapine on foam cells inhibits cholesterol uptake, activates cholesterol efflux, and converts macrophages from pro-inflammatory M1 to anti-inflammatory M2. This study confirms the abundance of sinapine in rapeseed oil by-products and elucidates the biochemical mechanisms of sinapine that alleviates macrophage foaming, which may provide new perspectives for reprocessing rapeseed oil by-products.

Selective deficiency of UCP-1 and adropin may lead to different subtypes of anti-neutrophil cytoplasmic antibody-associated vasculitis

Anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is a systemic autoimmune disease that is prone to respiratory and renal failures. Its major target antigens are serine protease 3 (PR3) and myeloperoxidase (MPO), but the determinants of PR3 and MPO subtypes are still unclear. Uncoupling protein-1 (UCP-1) and adropin (Adr) regulate mutually and play an important role in endothelial cell injury. In this study, adropin and UCP-1 knockout (AdrKO and UCP-1-KO) models were established on the basis of C57BL/6 J mice. The results showed that UCP-1-KO and AdrKO mice similar to AAV: significant inflammatory cell infiltration, vascular wall damage, and erythrocyte extravasation. The pathological basis of AdrKO was that endothelial cells adhered and activated neutrophils to release MPO, and the core gene was peroxisome proliferator-activated receptor gamma (PPARG). However, UCP-1-KO induced PR3 release, and the accumulation and expression of tissue factor on the vascular wall, and the core gene was peroxisome proliferator-activated receptor delta (PPARD). The present study verified that the subtypes of AAV may be genetically different diseases and it also provide novel experimental evidence for clinical differentiation of the two subtypes.

Macrophage polarization states in atherosclerosis

Atherosclerosis, a chronic inflammatory condition primarily affecting large and medium arteries, is the main cause of cardiovascular diseases. Macrophages are key mediators of inflammatory responses. They are involved in all stages of atherosclerosis development and progression, from plaque formation to transition into vulnerable plaques, and are considered important therapeutic targets. Increasing evidence suggests that the modulation of macrophage polarization can effectively control the progression of atherosclerosis. Herein, we explore the role of macrophage polarization in the progression of atherosclerosis and summarize emerging therapies for the regulation of macrophage polarization. Thus, the aim is to inspire new avenues of research in disease mechanisms and clinical prevention and treatment of atherosclerosis.

Novel Radiotracers for Molecular Imaging of Myocardial Inflammation: an Update Focused on Clinical Translation of Non-18F-FDG Radiotracers

Purpose of Review

The purpose of this paper is to provide a focused update on recent advances in non-18F-FDG radiotracers for myocardial inflammatory diseases, with a focus on cardiac sarcoidosis and myocarditis.

Recent Findings

Novel radiotracers targeting molecular features of inflammation have the potential to visualize underlying molecular mechanisms key to the pathogenesis of inflammatory cardiomyopathies such as sarcoidosis and myocarditis. These radiotracers may provide unique opportunities for improved mechanistic insight, higher specificity, and better quantification of disease activity, as well as potential for guidance and monitoring of immunomodulatory therapies.

Summary

Novel radiotracers provide unique possibilities in diagnosis, prognostic performance, and therapy guidance for cardiac sarcoidosis and myocarditis.

Influenza Virus Infection during Pregnancy as a Trigger of Acute and Chronic Complications

Influenza A virus (IAV) infection during pregnancy disrupts maternal and fetal health through biological mechanisms, which are to date poorly characterised. During pregnancy, the viral clearance mechanisms from the lung are sub-optimal and involve hyperactive innate and adaptive immune responses that generate wide-spread inflammation. Pregnancy-related adaptations of the immune and the cardiovascular systems appear to result in delayed recovery post-viral infection, which in turn promotes a prolonged inflammatory phenotype, increasing disease severity, and causing maternal and fetal health problems. This has immediate and long-term consequences for the mother and fetus, with complications including acute cardiopulmonary distress syndrome in the mother that lead to perinatal complications such as intrauterine growth restriction (IUGR), and birth defects; cleft lip, cleft palate, neural tube defects and congenital heart defects. In addition, an increased risk of long-term neurological disorders including schizophrenia in the offspring is reported. In this review we discuss the pathophysiology of IAV infection during pregnancy and its striking similarity to other well-established complications of pregnancy such as preeclampsia. We discuss general features of vascular disease with a focus on vascular inflammation and define the "Vascular Storm" that is triggered by influenza infection during pregnancy, as a pivotal disease mechanism for short and long term cardiovascular complications.

Microbiota-derived tryptophan metabolites in vascular inflammation and cardiovascular disease

The essential amino acid tryptophan (Trp) is metabolized by gut commensals, yielding in compounds that affect innate immune cell functions directly, but also acting on the aryl hydrocarbon receptor (AHR), thus regulating the maintenance of group 3 innate lymphoid cells (ILCs), promoting T helper 17 (TH17) cell differentiation, and interleukin-22 production. In addition, microbiota-derived Trp metabolites have direct effects on the vascular endothelium, thus influencing the development of vascular inflammatory phenotypes. Indoxyl sulfate was demonstrated to promote vascular inflammation, whereas indole-3-propionic acid and indole-3-aldehyde had protective roles. Furthermore, there is increasing evidence for a contributory role of microbiota-derived indole-derivatives in blood pressure regulation and hypertension. Interestingly, there are indications for a role of the kynurenine pathway in atherosclerotic lesion development. Here, we provide an overview on the emerging role of gut commensals in the modulation of Trp metabolism and its influence in cardiovascular disease development.

Arterial Stiffness and Adult Onset Vasculitis: A Systematic Review

Chronic inflammation represents the cornerstone of the raised cardiovascular (CV) risk in patients with inflammatory rheumatic diseases (IRD), including vasculitis. Standardized mortality ratios in these patients are higher as compared to the general population, and the excess of premature mortality is due to early atherosclerotic events. Thus, IRD patients need appropriate CV risk assessment and management according to this CV disease (CVD) burden. Adequate control of CV risk is still lacking in usual care, but early diagnosis of silent and subclinical CVD is crucial to improve the long-term prognosis of these patients. Increased arterial stiffness may provide a pathophysiological link between inflammation and increased cardiovascular risk. Several noninvasive methods are now available to estimate artery stiffness in the clinical setting, including pulse wave velocity assessment. The independent predictive value of arterial stiffness for cardiovascular events has been demonstrated in general as well as in selected populations, and reference values adjusted for age and blood pressure have been suggested. Thus, arterial stiffness is an interesting biomarker for cardiovascular risk stratification. This systematic review summarizes the additional value that PWV measurement can provide in the setting of vasculitis, with a focus in the different clinical stages and CV risk prevention. This systematic review is registered with registration number: Prospero CRD42021259603.

Platelet-leukocyte crosstalk in COVID-19: How might the reciprocal links between thrombotic events and inflammatory state affect treatment strategies and disease prognosis?

Platelet-leukocyte crosstalk is commonly manifested by reciprocal links between thrombosis and inflammation. Platelet thrombus acts as a reactive matrix that recruits leukocytes to the injury site where their massive accumulation, activation and migration promote thrombotic events while triggering inflammatory responses. As a life-threatening condition with the associations between inflammation and thrombosis, COVID-19 presents diffuse alveolar damage due to exaggerated macrophage activity and cytokine storms. These events, together with direct intracellular virus invasion lead to pulmonary vascular endothelialitis, cell membranes disruption, severe endothelial injury, and thrombosis. The developing pre-alveolar thrombus provides a hyper-reactive milieu that recruits circulating leukocytes to the injury site where their activation contributes to thrombus stabilization and thrombosis propagation, primarily through the formation of Neutrophil extracellular trap (NET). NET fragments can also circulate and deposit in further distance where they may disseminate intravascular thrombosis in severe cases of disease. Thrombi may also facilitate leukocytes migration into alveoli where their accumulation and activation exacerbate cytokine storms and tissue damage, further complicating the disease. Based on these mechanisms, whether an effective anti-inflammatory protocol can prevent thrombotic events, or on the other hand; efficient antiplatelet or anticoagulant regimens may be associated with reduced cytokine storms and tissue damage, is now of interests for several ongoing researches. Thus shedding more light on platelet-leukocyte crosstalk, the review presented here discusses the detailed mechanisms by which platelets may contribute to the pathogenesis of COVID-19, especially in severe cases where their interaction with leukocytes can intensify both inflammatory state and thrombosis in a reciprocal manner.

Regulatory Mechanism of MicroRNA-9 / Long Non-Coding RNA XIST Expression on Mouse Macrophage RAW264.7 Apoptosis Induced by Oxidized Low Density Lipoprotein

It aims to analyze the influential mechanism of microRNA-9 (miR-9) and long non-coding RNA XIST (lncRNA XIST) expression on the proliferation and apoptosis of macrophages induced by oxidized-low density lipoprotein (ox-LDL). Firstly, lncRNA XIST overexpression vector was constructed, and then RAW264.7 cells were used as the research object. Methylthiazolyl tetrazolium (MTT) method, flow cytometry, and Western blot were used to detect and compare the differences of cell proliferation, apoptosis, and the expression levels of apoptosis signal-regulating kinase 1 (ASK1), c-Jun N-terminal kinase (JNK), matrix metalloproteinase-9 (MMP-9), and B-cell lymphoma-2 (Bcl-2) after ox-LDL induction and transfection of miR-9 mimic, miR-9 inhibitor and XIST expression vector, respectively. The results showed that lncRNA XIST overexpression vector was successfully constructed and transfected into cells, wh5ich can inhibit the expression level of miR-9. Compared with the normal control group, ox-LDL can inhibit cell proliferation, promote cell apoptosis, and increase the expression level of target protein. Moreover, transfection of XIST expression vector based on ox-LDL induction can significantly enhance the inhibition of cell proliferation, and promote cell apoptosis and the expression of target protein. Transfection of miR-9 mimic can improve the biological changes induced by ox-LDL. After co-transfection of miR-9 mimic and XIST expression vector based on ox-LDL induction, cell proliferation, apoptosis, and target protein expression level were not significantly different from those induced by ox-LDL alone. In summary, the increased expression level of miR-9 can inhibit the apoptosis of macrophages induced by ox-LDL. lncRNA XIST can positively regulate the apoptosis of macrophages induced by ox-LDL.

Inhaled silica nanoparticles exacerbate atherosclerosis through skewing macrophage polarization towards M1 phenotype

BACKGROUND AND AIMS

Exposure to environmental nanoparticles is related to the adverse impact on health, including cardiovascular system. Various forms of nanoparticles have been reported to interact with endothelium and induce inflammation. However, the potential role of nanoparticles in the pathogenesis of atherosclerosis and their mechanisms of action are still unclear. The aim of this study was to investigate the effect of two broadly used nanomaterials, which also occur in natural environment - silicon oxide (SiO2) and ferric oxide (Fe2O3) in the form of nanoparticles (NPs) - on the development of atherosclerosis.

METHODS

We used apolipoprotein E-knockout mice exposed to silica and ferric oxide nanoparticles in a whole body inhalation chamber.

RESULTS

Inhaled silica nanoparticles augmented the atherosclerotic lesions and increased the percentage of pro-inflammatory M1 macrophages in both the plaque and the peritoneum in apoE-/- mice. Exposure to ferric oxide nanoparticles did not enhance atherogenesis process, however, it caused significant changes in the atherosclerotic plaque composition (elevated content of CD68-positive macrophages and enlarged necrotic core accompanied by the decreased level of M1 macrophages). Both silica and ferric oxide NPs altered the phenotype of T lymphocytes in the spleen by promoting polarization towards Th17 cells.

CONCLUSIONS

Exposure to silica and ferric oxide nanoparticles exerts impact on atherosclerosis development and plaque composition. Pro-atherogenic abilities of silica nanoparticles are associated with activation of pro-inflammatory macrophages.

Atherosclerosis: Pathogenesis and Key Cellular Processes, Current and Emerging Therapies, Key Challenges, and Future Research Directions

Atherosclerosis is the principal cause of cardiovascular disease that continues to be a substantial drain on healthcare systems, being responsible for about 31% of all global deaths. Atherogenesis is influenced by a range of factors, including oxidative stress, inflammation, hypertension, and hyperlipidemia, and is ultimately driven by the accumulation of low-density lipoprotein cholesterol within the arterial wall of medium and large arteries. Lipoprotein accumulation stimulates the infiltration of immune cells (such as monocytes/macrophages and T-lymphocytes), some of which take up the lipoprotein, leading to the formation of lipid-laden foam cells. Foam cell death results in increased accumulation of dead cells, cellular debris and extracellular cholesterol, forming a lipid-rich necrotic core. Vascular smooth muscle cells from the arterial media also migrate into the intima layer and proliferate, taking up the available lipids to become foam cells and producing extracellular matrix proteins such as collagen and elastin. Plaque progression is characterized by the formation of a fibrous cap composed of extracellular matrix proteins and smooth muscle cells, which acts to stabilize the atherosclerotic plaque. Degradation, thinning, and subsequent rupture of the fibrous cap leads to lumen-occlusive atherothrombosis, most commonly resulting in heart attack or stroke. This chapter describes the pathogenesis of atherosclerosis, current and emerging therapies, key challenges, and future directions of research.

Key Roles of Inflammation in Atherosclerosis: Mediators Involved in Orchestrating the Inflammatory Response and Its Resolution in the Disease Along with Therapeutic Avenues Targeting Inflammation

Inflammation is a critical driver of all stages of atherosclerosis, from lesion development to plaque rupture. Cytokines are mediators of the immune response and in atherosclerosis, the balance of anti- and pro-inflammatory cytokines is tipped in favor of the latter, resulting in persistent and unresolved inflammation. Although reducing plasma cholesterol levels mainly via the use of statins has positively impacted patient outcomes and reduced mortality rates, the presence of significant residual inflammation and cardiovascular risk posttherapy emphasizes the prevailing risk of primary and secondary events driven by inflammation independently of hyperlipidemia. Given the dominant role of inflammation in driving pathogenesis, alternative therapeutic avenues beyond targeting lowering of plasma lipids are required. This chapter will discuss the role of inflammation and pro-inflammatory cytokines in driving atherogenesis and disease progression, the therapeutic potential of targeting cytokines for atherosclerosis and promising avenues in this area.

Age as a risk factor in vasculitis

Two vasculitides, giant cell arteritis (GCA) and Takayasu arteritis (TAK), are recognized as autoimmune and autoinflammatory diseases that manifest exclusively within the aorta and its large branches. In both entities, the age of the affected host is a critical risk factor. TAK manifests during the 2nd-4th decade of life, occurring while the immune system is at its height of performance. GCA is a disease of older individuals, with infrequent cases during the 6th decade and peak incidence during the 8th decade of life. In both vasculitides, macrophages and T cells infiltrate into the adventitia and media of affected vessels, induce granulomatous inflammation, cause vessel wall destruction, and reprogram vascular cells to drive adventitial and neointimal expansion. In GCA, abnormal immunity originates in an aged immune system and evolves within the aged vascular microenvironment. One hallmark of the aging immune system is the preferential loss of CD8⁺ T cell function. Accordingly, in GCA but not in TAK, CD8⁺ effector T cells play a negligible role and anti-inflammatory CD8⁺ T regulatory cells are selectively impaired. Here, we review current evidence of how the process of immunosenescence impacts the risk for GCA and how fundamental differences in the age of the immune system translate into differences in the granulomatous immunopathology of TAK versus GCA.

The relationship with the stability between GRP78, CHOP and human carotid atherosclerotic plaque

BACKGROUND

Current researches on human carotid atherosclerosis (AS) plaques are focused on vulnerable plaques, and various methods have been clinically used to detect vulnerable plaques to prevent adverse events. GRP78 and CHOP, as markers in the endoplasmic reticulum stress (ERS), have a certain relationship with the stability of plaque tissue.

METHODS

In this study, 150 plaque specimens were obtained from carotid endarterectomy (CEA). According to pathology, they were divided into two groups: stable plaque and vulnerable plaque. Immunohistochemistry was used to semi-quantitate and localize the target molecule. Western blot and RT-qPCR were used to detect the expression of GRP78 and CHOP in the samples. The receiver operating characteristic curve (ROC curve) judges the significance of the target molecule as a biomarker for the diagnosis of vulnerable plaques.

RESULTS

The results of immunohistochemistry showed that the target molecules of GRP78 and CHOP were mainly expressed in inflammatory cells and vascular endothelial cells; Western blot and RT-qPCR techniques were used to detect the expression of GRP78 and CHOP in different pathlogical types of plaques, which respectively indicated that there were differential expressions. The expression in vulnerable plaques was significantly higher than that in stable plaques (P < 0.05). analysis with ROC, the areas under curves (AUC) of the GRP78 and CHOP data were calculated as 0.792 and 0.850, respectively and the combination showed the largest AUC of 0.870.

CONCLUSION

In endoplasmic reticulum stress, GRP78 and CHOP are significantly higher expressions in vulnerable plaques than stable's, which indicated that GRP78 and CHOP played a certain role in the occurrence and development of human carotid atherosclerosis and vulnerable plaques; GRP78 and CHOP are promising molecular biomarkers for identifying the endoplasmic reticulum stress situation, atherosclerosis and plaque stability. They also could provide a potential drug targets for the prevention and treatment of atherosclerosis.

Functionally Heterogenous Macrophage Subsets in the Pathogenesis of Giant Cell Arteritis: Novel Targets for Disease Monitoring and Treatment

Giant cell arteritis (GCA) is a granulomatous large-vessel vasculitis that affects adults above 50 years of age. In GCA, circulating monocytes are recruited to the inflamed arteries. With cues from the vascular microenvironment, they differentiate into macrophages and play important roles in the pathogenesis of GCA via pro-inflammatory cytokine production and vascular remodeling. However, a deeper understanding of macrophage heterogeneity in GCA pathogenesis is needed to assist the development of novel diagnostic tools and targeted therapies. Here, we review the current knowledge on macrophage heterogeneity and diverse functions of macrophage subsets in the pathogenesis of GCA. We next discuss the possibility to exploit their heterogeneity as a source of novel biomarkers and as targets for nuclear imaging. Finally, we discuss novel macrophage-targeted therapies and future directions for targeting these cells in GCA.

Macrophage-biomimetic anti-inflammatory liposomes for homing and treating of aortic dissection

Aortic dissection (AD) is a life-threatening disease featured by the dissection of intimal layer and the formation of a blood-filled false lumen within the aortic wall. Recent studies revealed that the formation and progression of AD lesions is closely related to vascular inflammation and macrophage infiltration. However, the potential efficacy of anti-inflammatory therapy on the prevention and treatment of AD has not been extensively investigated. Herein, we proposed a biomimetic anti-inflammatory liposome (PM/TN-CCLP) co-loaded with curcumin and celecoxib (CC), modified with cell-penetrating TAT-NBD fusion peptide (TN), and further camouflaged by isolated macrophage plasma membrane (PM), as a potential nanotherapy for AD. In vitro results showed that PM/TN-CCLP exhibited low cytotoxicity and elevated cellular uptake by inflammatory macrophages, and prominently inhibited the transendothelial migration, inflammatory responses and ROS generation of macrophages. Moreover, the PM/TN-CCLP treatment significantly prevented the H₂O₂-induced smooth muscle cell apoptosis. In vivo experiments were performed on the acute and chronic AD mouse models, respectively. The results verified the elevated accumulation of PM-camouflaged liposome at the aorta lesions. Further, the anti-inflammatory liposomes, especially PM/TN-CCLP, could reduce the rupture rate of dissection, prevent the loss of elastic fibers, and reduce MMP-9 expression as well as macrophage infiltration in the aortic lesions. Notably, as compared with free drugs and TN-CCLP, the PM/TN-CCLP treatment displayed the longest survival period along with the minimal aortic injury on both acute and chronic AD mice. Taken together, the present study suggested that the macrophage-biomimetic anti-inflammatory nanotherapy would be a promising strategy for the prevention and therapy of aortic dissection.

HOXA9 inhibitors promote microcirculation of coronary arteries in rats via downregulating E-selectin/VCAM-1

Atherosclerosis (AS) is a chronic pathophysiological process that causes high mortality and morbidity. It has previously been reported that homeobox A9 (HOXA9) may participate in regulation of the cardiovascular system and the pathology of AS by upregulating E-selectin and vascular cell adhesion molecule-1 (VCAM-1). Thus, inhibiting HOXA9 could promote microcirculation of coronary arteries and could act as a potential therapy for AS treatment. Sprague-Dawley rats were randomly divided into four groups, as follows: i) AS; ii) AS + HOXA9 inhibitor; iii) AS + small interfering RNA-HOXA9 and iv) normal control. ELISA was used to measure the levels of TNF-α, IL-1β, IL-12, C-C motif chemokine ligand 25 (CCL25), low-density lipoprotein (LDL), high-density lipoprotein (HDL) and very-low-density lipoprotein (VLDL). Flow cytometry was employed to detect the content of M1 macrophages. Hematoxylin & eosin (H&E) staining was performed to observe the morphology of the coronary arteries. Oil red O staining was conducted for the evaluation of lipid accumulation. Immunohistochemistry was used to visualize the protein expression levels of HOXA9 in the coronary arteries. Western blotting was utilized to determine the protein expression levels of HOXA9, platelet factor-4 (PF4), E-selectin and VCAM-1. HOXA9 inhibitors were found to downregulate the levels of TNF-α, IL-1β, IL-12, CCL25, LDL and VLDL, and upregulate HDL levels in the blood of AS rats. The content of M1 macrophages was also decreased following injection of HOXA9 inhibitors in the AS group. H&E and oil red O staining analysis indicated that HOXA9 inhibitors attenuated vascular symptoms and lipid formation in AS rats. Furthermore, western blotting suggested that inhibition of HOXA9 reduced the expression levels of PF4, E-selectin and VCAM-1, while overexpression of PF4 resulted in the opposite effects. The present study revealed that inhibiting HOXA9 alleviated the symptoms of AS via downregulation of the PF4 and E-selectin/VCAM-1 pathway to promote microcirculation in the coronary arteries of AS rats. These findings indicated that HOXA9 inhibitors may have the potential to succeed in the treatment of AS.

COVID-19: captures iron and generates reactive oxygen species to damage the human immune system

Currently, the novel coronavirus pneumonia has been widespread globally, and there is no specific medicine. In response to the emergency, we employed bioinformatics methods to investigate the virus's pathogenic mechanism, finding possible control methods. We speculated in previous studies that E protein was associated with viral infectivity. The present study adopted the domain search techniques to analyse the E protein. According to the results, the E protein could bind iron or haem. The iron and haem bound by the E protein came from the attacked haemoglobin and phagocytes. When E protein was attached to haem, it synthesised oxygen and water into superoxide anions, hydrogen peroxide and hydroxyl radicals. When the iron-bound E protein and the haem-bound E protein worked together, they converted superoxide anions and hydrogen peroxide into oxygen and water. These were the "ROS attack" and "ROS escape" of the virus. "ROS attack" damaged the tissues or cells exposed on the surface of the virus, and "ROS escape" decomposed the superoxide anion and hydrogen peroxide that attacked the virus. When NK cells were exposed to infected cells, viruses that had not shed from the infected cells' surface damaged them through "ROS attack". In addition, lymphocytes such as T cells and B cells, which could be close to the antigen of the virus surface, were also easily damaged or killed by the "ROS attack", generating a decrease in lymphocytes. When memory B cells were exposed to the virus's surface antigen, they were also damaged by "ROS attack", resulting in the patient's re-infection. The virus applied the "ROS escape" to decompose hydrogen peroxide released by phagocytes into oxygen and water. The surrounding cells were replenished with oxygen, and the patient was in a "happy hypoxia" state. When the phagocytes swallowed the virus, the E protein converted superoxide anions into oxygen and water. In this way, the virus parasitized in the vesicles of the phagocyte. While virus was in the lysosome, the E protein generated ROS to damage nearby hydrolases. In this way, the virus parasitized the lysosome. Excessive hydroxyl free radicals destroyed the membrane structure of the lysosome, causing the hydrolase release from lysosome, autophagy of phagocytic cells and subsequent cell death. As a result, the colonizing phagocytes of the virus was associated with asymptomatic infection or retest-positive. Briefly, the virus inhibited the immune system through "ROS escape", and damaged the immune system by "ROS attack". The destruction instigated a strong cytokine storm, leading to organ failure and complications.

Potential Role of Macrophage Phenotypes and CCL2 in the Pathogenesis of Takayasu Arteritis

Objectives

To investigate vascular macrophage phenotype as well as vascular and peripheral chemokine (C-C motif) ligand 2 (CCL2) expression during different stages of disease progression in patients with Takayasu Arteritis (TA).

Methods

In this study, 74 patients with TA and 50 controls were recruited. TA disease activity was evaluated with Kerr scores. Macrophage phenotype and CCL2 expression were examined by immunohistochemistry in vascular specimens from 8 untreated and 7 treated TA patients, along with 4 healthy controls. Serum CCL2 were quantified by enzyme-linked immune-absorbent assay from TA patients at baseline (n=59), at 6-months (n=38), and from 46 healthy volunteers. Vascular macrophage phenotype, vascular CCL2 expression and serum CCL2 levels during different stages, as well as the relationship between serum CCL2 and disease activity or other inflammatory parameters (erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and interleukin 6 (IL-6)) were investigated.

Results

In untreated patients, vascular M1 macrophages and CCL2 showed increased expression, mainly in the adventitia. In contrast, in treated patients, vascular adventitial M1 and CCL2 expression were decreased, while vascular medial M2 macrophages and CCL2 levels were increased. Distribution of macrophages and CCL2 was consistent within the TA vascular lesions regardless of the disease stage. Furthermore, peripheral CCL2 was elevated in patients with TA (TA: 160.30 ± 120.05 vs. Control: 65.58 ± 54.56 pg/ml, P < 0.001). CCL2 levels were found to correlate with ESR, CRP, and IL-6 (all R values between 0.55 and 0.6, all P < 0.001). Receiver operating curve analysis demonstrated that CCL2 (at the cut-off value of 100.36 pg/ml) was able to predict disease activity (area under the curve = 0.74, P = 0.03). Decrease in CCL2 level was observed in patients with clinical remission (CR), but not in patients without CR, after 6 months of treatment (CR patients: baseline 220.18 ± 222.69 vs. post-treatment 88.71 ± 55.89 pg/ml, P = 0.04; non-CR patients: baseline 142.45 ± 104.76 vs. post-treatment 279.49 ± 229.46 pg/ml, P = 0.02).

Conclusions

Macrophages contribute to vascular pathological changes in TA by undergoing phenotype transformation. CCL2 is an important factor for recruiting macrophages and a potential biomarker for disease activity.

The Impact of the Ca2+-Independent Phospholipase A2β (iPLA2β) on Immune Cells

The Ca²⁺-independent phospholipase A₂β (iPLA₂β) is a member of the PLA₂ family that has been proposed to have roles in multiple biological processes including membrane remodeling, cell proliferation, bone formation, male fertility, cell death, and signaling. Such involvement has led to the identification of iPLA₂β activation in several diseases such as cancer, cardiovascular abnormalities, glaucoma, periodontitis, neurological disorders, diabetes, and other metabolic disorders. More recently, there has been heightened interest in the role that iPLA₂β plays in promoting inflammation. Recognizing the potential contribution of iPLA₂β in the development of autoimmune diseases, we review this issue in the context of an iPLA₂β link with macrophages and T-cells.

Vascular Inflammation Is Associated with Loss of Aquaporin 1 Expression on Endothelial Cells and Increased Fluid Leakage in SARS-CoV-2 Infected Golden Syrian Hamsters

Vascular changes represent a characteristic feature of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection leading to a breakdown of the vascular barrier and subsequent edema formation. The aim of this study was to provide a detailed characterization of the vascular alterations during SARS-CoV-2 infection and to evaluate the impaired vascular integrity. Groups of ten golden Syrian hamsters were infected intranasally with SARS-CoV-2 or phosphate-buffered saline (mock infection). Necropsies were performed at 1, 3, 6, and 14 days post-infection (dpi). Lung samples were investigated using hematoxylin and eosin, alcian blue, immunohistochemistry targeting aquaporin 1, CD3, CD204, CD31, laminin, myeloperoxidase, SARS-CoV-2 nucleoprotein, and transmission electron microscopy. SARS-CoV-2 infected animals showed endothelial hypertrophy, endothelialitis, and vasculitis. Inflammation mainly consisted of macrophages and lower numbers of T-lymphocytes and neutrophils/heterophils infiltrating the vascular walls as well as the perivascular region at 3 and 6 dpi. Affected vessels showed edema formation in association with loss of aquaporin 1 on endothelial cells. In addition, an ultrastructural investigation revealed disruption of the endothelium. Summarized, the presented findings indicate that loss of aquaporin 1 entails the loss of intercellular junctions resulting in paracellular leakage of edema as a key pathogenic mechanism in SARS-CoV-2 triggered pulmonary lesions.

Cardiovascular events and the role of accelerated atherosclerosis in systemic vasculitis

The spectrum of inflammatory blood vessel diseases includes both atherosclerosis and the primary systemic vasculitides. Although the inciting triggers differ, significant overlap exists in the mechanisms that contribute to sustained inflammation and vascular damage in both entities. With improvement in therapeutics to control acute vasculitis leading to longer survival, cardiovascular morbidity and mortality has emerged as the leading cause of death for vasculitis patients. Cardiovascular events likely occur as a consequence of vasculitis, vascular damage from prior inflammation causing a sustained procoagulant state, and accelerated atherosclerosis. In this review, we discuss the latest evidence regarding risk of cardiovascular events in patients with major forms of primary systemic vasculitis, and review the mechanisms by which accelerated atherosclerosis may occur.

The feasible maintenance dose of corticosteroid in Takayasu arteritis in the era of biologic therapy

Objective: Although biologic agents are used in Takayasu arteritis (TAK), corticosteroids are still the mainstay of treatment. This study aimed to investigate the feasible maintenance dose of prednisolone (PSL) in the biologic therapy era.Method: We enrolled 93 patients with TAK who satisfied the criteria of the American College of Rheumatology and visited our department from 2008 to 2018. The clinical characteristics and PSL dose of the patients were retrospectively evaluated.Results: The mean ± sd maintenance dose of PSL was 5.0 ± 3.0 mg/day. In patients having TAK for > 20 years, PSL discontinuation and drug-free status were achieved in 27.2% and 18%, respectively. Although tapering the PSL dose to 10 mg/day was achieved within 12 months, tapering to 5 mg/day required 10 years. Relapse significantly interfered with the PSL dose reduction. The clinical characteristics of patients with relapse included a lower rate of combination therapy using immunosuppressants. Moreover, biologics were used in > 60% of patients with relapse. Tapering of PSL was significantly possible in patients receiving biologics and additional relapse was observed in 6.3% and 50% of patients with and without biologics, respectively. Such PSL-sparing effect enabled the reduction of the median PSL dose from 10 to 5 mg/day. Steroid discontinuation was achieved in some patients.Conclusions: The use of biologics significantly reduced the PSL dose in relapsed patients. A PSL dose of ≤ 5 mg/day is a feasible target for TAK, especially when biologic agents are used. Nevertheless, corticosteroid discontinuation may also be the target in some patients.

Ghrelin suppresses migration of macrophages via inhibition of ROCK2 under chronic intermittent hypoxia

Objectives

Migration of macrophages and atherosclerosis result in various diseases, including coronary heart disease. This study aimed to clarify the roles that ghrelin and Rho-associated coiled-coil-containing protein kinase 2 (ROCK2) play in migration of macrophages under chronic intermittent hypoxia (CIH).

Methods

A rat model of CIH was constructed and changes in ghrelin and ROCK2 protein expression were measured by western blot assay. The migratory ability of macrophages was determined by the transwell assay. Hematoxylin and eosin staining was applied to detect the changes in intima-media thickness.

Results

We found that CIH enhanced migration of macrophages, and this effect was attenuated by exogenous ghrelin. Additionally, the facilitative effect of CIH on migration of macrophages was strengthened or decreased by upregulation or downregulation of ROCK2, respectively. This phenomenon indicated that ROCK2 was involved in CIH-induced migration in macrophages. Furthermore, western blot and transwell assays showed that ghrelin inhibited CIH-induced migration via ROCK2 suppression in macrophages.

Conclusions

In summary, the present study shows that ghrelin inhibits CIH-induced migration via ROCK2 suppression in macrophages. Our research may help lead to identifying a new molecular mechanism for targeted therapy of atherosclerosis and its associated coronary artery diseases under intermittent hypoxia.

Vasculoprotective effects of ginger (Zingiber officinale Roscoe) and underlying molecular mechanisms

Ginger (Zingiber officinale Roscoe) is a common and widely used spice. It is rich in various chemical constituents, including phenolic compounds, terpenes, polysaccharides, lipids, organic acids, and raw fibers. Herein, we reviewed its effects on the vascular system. Studies utilizing cell cultures or animal models showed that ginger constituents alleviate oxidative stress and inflammation, increase nitric oxide synthesis, suppress vascular smooth muscle cell proliferation, promote cholesterol efflux from macrophages, inhibit angiogenesis, block voltage-dependent Ca2+ channels, and induce autophagy. In clinical trials, ginger was shown to have a favorable effect on serum lipids, inflammatory cytokines, blood pressure, and platelet aggregation. Taken together, these studies point to the potential benefits of ginger and its constituents in the treatment of hypertension, coronary artery disease, peripheral arterial diseases, and other vascular diseases.

Proteomic analysis of urine reveals biomarkers for the diagnosis and phenotyping of abdominal-type Henoch-Schonlein purpura

BACKGROUND

Abdominal-type Henoch-Schonlein purpura (HSP) is a common refractory disease in children. Currently, no specific diagnostic biomarker is available for HSP.

METHODS

Children with abdominal type HSP were first diagnosed with three syndromes using Chinese traditional medicine. The urinary proteomes among the three syndromes of patients with abdominal type HSP and healthy controls were compared using two label-free proteomics quantifications, including data-dependent acquisition and data-independent acquisition.

RESULTS

For the comparison between patients with abdominal type HSP and healthy children, a total of 75 differential urinary proteins were identified by determining the overlap of the two experiments. The ingenuity pathway analysis (IPA) analysis showed that these differential proteins were correlated with the pathogenesis of abdominal type HSP. Of these, 37 proteins were distributed in 13 solid tissues as tissue-enriched proteins. Monitoring changes in these proteins might help us detect uncommon clinical manifestations of HSP. Patients with abdominal type HSP can be further distinguished into three syndromes based on the urine proteome. Finally, a panel of six urinary proteins (P25774, P09417, Q7Z5L0, P60900, P14550 and P09668) was constructed for both the diagnosis and phenotyping of abdominal type HSP.

CONCLUSIONS

Urinary protein biomarkers for the diagnosis and phenotyping of abdominal type HSP were identified, which will contribute to the personalized treatment of patients with abdominal type HSP.

High expression of pro-inflammatory cytokine genes IL-1β and IL-1R2 upon TLR4 activation in Takayasu arteritis

Toll-like receptors (TLR) 4 and its endogenous ligands are highly expressed in aorta. In the present study, we have explored the effect of TLR-4 activation by pro-inflammatory and angiogenic factors in PBMCs of patients with Takayasu Arteritis (TA). In the screening cohort, PBMCs of TA (n = 6) and healthy controls (n = 6) were stimulated with LPS and cultured. mRNA expression of 84 genes were quantitated by RT2 Profiler™ PCR Array kit in PBMCs. Validation set of additional PBMCs from TA (n = 7) and healthy controls [HC) (n = 7) were then stimulated with LPS to study expression of selected genes with delta Ct > 0.1 in the screening cohort. Significant gene expressions were correlated with Indian Takayasu arteritis activity scores (ITAS 2010). Increased expression of CCL2 was observed only in unstimulated PBMCs of patients with TA [median relative difference (RD) of 2.37] as compared to HC (RD 1.37, p < 0.03) in validation cohort, while stimulation with TLR4 ligand led to increased mRNA expression of IL-1β (RD 7.9, p < 0.028) and IL-1R2 (RD 0.08 p < 0.013) genes as compared to that of HC [RD of 5.32 for IL-1β and 0.01 for IL-1R2, respectively] in validation cohort. TLR4 activation also led to significantly higher expression of HPSE, TIMP1 and low expression of VEGFB, S1PR1, SERPINF1, ANGPLT4, ANGPT2, TIE1 and NOS3 genes in the screening cohort. But expression of VEGFB was not significant in validation cohort. The significant gene expressions, however, did not correlate with ITAS [ITAS2010 and ITAS-A (CRP)]. TLR4 activation leads to increased expression of IL-1β and IL-1R2 genes in PBMCs of patients with TA.

Sheep-Associated Malignant Catarrhal Fever: Role of Latent Virus and Macrophages in Vasculitis

Malignant catarrhal fever (MCF) is a sporadic, generally fatal disease caused by gammaherpesviruses in susceptible dead-end hosts. A key pathological process is systemic vasculitis in which productively infected cytotoxic T cells play a major role. Nonetheless, the pathogenesis of MCF vasculitis is not yet clear. We hypothesized that it develops due to an interaction between virus-infected cells and immune cells, and we undertook a retrospective in situ study on the rete mirabile arteries of confirmed ovine gammaherpesvirus-2 (OvHV-2)-associated MCF cases in cattle, buffalo, and bison. Our results suggest that the arteritis develops from an adventitial infiltration of inflammatory cells from the vasa vasorum, and recruitment of leukocytes from the arterial lumen that leads to a superimposed infiltration of the intima and media that can result in chronic changes including neointimal proliferation. We found macrophages and T cells to be the dominant infiltrating cells, and both could proliferate locally. Using RNA in situ hybridization and immunohistology, we showed that the process is accompanied by widespread viral infection, not only in infiltrating leukocytes but also in vascular endothelial cells, medial smooth muscle cells, and adventitial fibroblasts. Our results suggest that OvHV-2-infected T cells, monocytes, and locally proliferating macrophages contribute to the vasculitis in MCF. The initial trigger or insult that leads to leukocyte recruitment and activation is not yet known, but there is evidence that latently infected, activated endothelial cells play a role in this. Activated macrophages might then release the necessary pro-inflammatory mediators and, eventually, induce the characteristic vascular changes.

Danlou tablet inhibits the inflammatory reaction of high-fat diet-induced atherosclerosis in ApoE knockout mice with myocardial ischemia via the NF-κB signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Danlou tablet (DLT), a traditional herbal formula, has been used to treat chest discomfort (coronary atherosclerosis) in China. Although the anti-inflammatory activities of DLT have been proposed previously, the mechanisms of DLT in treating atherosclerosis with myocardial ischemia (AWMI) remain unknown.

AIM OF THE STUDY

Atherosclerosis can result in heart disease caused by stenosis or occlusion of the lumen, resulting in myocardial ischemia, hypoxia, or necrosis. In recent years, changes in people's diets, increased stress, and secondary fatigue and obesity etc. have resulted in increases in the number of patients with atherosclerosis. In cases where the condition has further developed, patients may suffer from myocardial ischemia, hypoxia, or necrosis. Many traditional Chinese medicine compounds have been prescribed for the treatment of AWMI. DLT has been used to treat chest discomfort (coronary atherosclerosis) in China. Based on previous research, the aim of this study was to further investigate the effect of DLT on AWMI, and describe the underlying mechanisms.

MATERIALS AND METHODS

To achieve this, an animal model of AWMI was established using apolipoprotein E (ApoE^-/-) mice fed a high fat diet combined with isoprenaline (ISO) injection. For comparison, mouse models of only atherosclerosis and only myocardial ischemia were included. In the treatment groups, mice were treated daily with DLT at 700 mg/kg for four weeks. Echocardiographic evaluation, hematoxylin and eosin (H&E) staining, oil red O staining, ELISAs, Western blots, and immunohistochemical analyses were subsequently used to investigate the mechanism of DLT based on the NF-κB signaling pathway.

RESULTS

The results indicate that the use of DLT is effective, to varying degrees, for the treatment of atherosclerosis, myocardial ischemia, and AWMI in mice. After DLT treatment, the left ventricular structure and morphology of the mice, the histopathology of cardiac tissue, and atherosclerotic plaques in the aortas all improved to varying degrees. DLT could play a therapeutic role by regulating the NF-κB signaling pathway related to inflammatory factors, including TNF-α, IL-6, IL-1β, IL-8, MMP-1 and MMP-2, as well as protein expression of NF-κB p-50 and IκB-α, and positive cell expression of NF-κB p-50, IκB-α and phospho-NF-κB p-50 in the model mice.

CONCLUSION

These preliminary results indicate that the therapeutic efficacy of DLT on high-fat diet-induced atherosclerosis in ApoE^-/- mice with myocardial ischemia could be exerted at least in part by regulating the NF-κB signaling pathway.

LncRNA-MAP3K4 regulates vascular inflammation through the p38 MAPK signaling pathway and cis-modulation of MAP3K4

Chronic vascular inflammation plays a key role in the pathogenesis of atherosclerosis. Long non-coding RNAs (lncRNAs) have emerged as essential inflammation regulators. We identify a novel lncRNA termed lncRNA-MAP3K4 that is enriched in the vessel wall and regulates vascular inflammation. In the aortic intima, lncRNA-MAP3K4 expression was reduced by 50% during the progression of atherosclerosis (chronic inflammation) and 70% during endotoxemia (acute inflammation). lncRNA-MAP3K4 knockdown reduced the expression of key inflammatory factors (eg, ICAM-1, E-selectin, MCP-1) in endothelial cells or vascular smooth muscle cells and decreased monocytes adhesion to endothelium, as well as reducing TNF-α, IL-1β, COX2 expression in macrophages. Mechanistically, lncRNA-MAP3K4 regulates inflammation through the p38 MAPK signaling pathway. lncRNA-MAP3K4 shares a bidirectional promoter with MAP3K4, an upstream regulator of the MAPK signaling pathway, and regulates its transcription in cis. lncRNA-MAP3K4 and MAP3K4 show coordinated expression in response to inflammation in vivo and in vitro. Similar to lncRNA-MAP3K4, MAP3K4 knockdown reduced the expression of inflammatory factors in several different vascular cells. Furthermore, lncRNA-MAP3K4 and MAP3K4 knockdown showed cooperativity in reducing inflammation in endothelial cells. Collectively, these findings unveil the role of a novel lncRNA in vascular inflammation by cis-regulating MAP3K4 via a p38 MAPK pathway.

Beyond Giant Cell Arteritis and Takayasu's Arteritis: Secondary Large Vessel Vasculitis and Vasculitis Mimickers

PURPOSE OF REVIEW

To provide an overview of mimickers of large vessel vasculitis (LVV), by the main presenting manifestation, i.e., systemic, vascular, and cranial manifestations.

RECENT FINDINGS

The main differential diagnoses in patients with giant cell arteritis (GCA) and Takayasu arteritis (TAK) presenting with systemic manifestations (i.e., fever, anorexia, weight loss, night sweats, arthralgia/myalgia, and/or increased inflammatory indexes) are neoplastic, infectious, or other inflammatory conditions. In patients with vascular manifestations (such as peripheral ischemia, vascular stenoses, or aneurysms), atherosclerosis and non-inflammatory vascular diseases should be excluded. In those presenting with predominant cranial symptoms (i.e., temporal headache, jaw claudication, scalp tenderness, transient or permanent vision loss), other causes of headache, cerebrovascular accidents, optic neuropathy, and neuromuscular syndromes need to be considered. The diagnosis of LVV maybe challenging, especially when patients present with atypical or incomplete clinical forms. In these cases, a multidisciplinary approach is strongly recommended.

[High-salt exposure induces macrophage polarization to promote proliferation and phenotypic transformation of co-cultured renal fibroblasts]

OBJECTIVE

To investigate high-salt exposure-induced polarization of mononuclear macrophages and the changes in proliferation and phenotypic transformation of renal fibroblasts in a co-culture system.

METHODS

Cultured mononuclear macrophages were exposed to high salt (161 mmol/L Na +) for 2 h and the surface markers of M0, M1 and M2-type macrophages were detected with RT-qPCR. The culture medium of the macrophages in normal and high-salt groups was collected for detection of the mRNA and protein levels of IL-6 and TGF-β1 using RT-qPCR and ELISA. A co-culture system of high salt-exposed macrophages and renal fibroblasts (NRK-49F) was established using a Transwell chamber, and the changes in proliferation and migration of NRK-49F cells were examined using EdU assay and Transwell assay, respectively. Western blotting was performed to detect the expressions of collagen I, collagen III and collagen α-SMA in NRK-49F cells.

RESULTS

The high salt-exposed macrophages showed significantly increased mRNA levels of M2-type macrophage surface markers mannose receptor and arginase (P < 0.05). The results of EdU and Transwell assays showed that NRK-49F cells co-cultured with high salt-exposed macrophages exhibited significantly increased proliferation and migration ability (P < 0.05). Co-culture with high salt-exposed macrophages resulted in significantly enhanced protein expressions of collagen I, collagen III and α-SMA in NRK-49F cells (P < 0.05) and significantly increased levels of IL-6 and TGF-β1 in the culture medium (P < 0.05).

CONCLUSIONS

High-salt exposure induces polarization of mononuclear macrophages into M2-type macrophages and promotes secretion of IL-6 and TGF-β1 by the macrophages to induce the proliferation and phenotypic transformation of NRK-49F cells.