Myeloperoxidase-Oxidized LDL Activates Human Aortic Endothelial Cells through the LOX-1 Scavenger Receptor

Association of environmental metallic and metalloid contaminants with cardiovascular and all-cause mortality: An umbrella review of systematic reviews and meta-analyses

AIM

The aim was to examine the relationship between exposure to environmental metallic and metalloid pollutants and cardiovascular disease (CVD) and all-cause mortality by integrating the information currently available from systematic reviews and meta-analyses.

METHOD

PubMed, Embase, and Web of Science for systematic reviews and meta-analyses were thoroughly searched up to October 9, 2024. Systematic reviews and meta-analyses of various kinds that evaluated the relationship between exposure to ambient metallic and metalloid pollutants and CVD and all-cause mortality were included. The methodological quality and the evidence quality were assessed using AMSTAR2 and GRADE, respectively.

RESULTS

We identified 25 meta-analyses and 81 health outcomes-76 unique outcomes from observational studies and 5 unique outcomes from RCTs-from 8,841 independent publications. Exposure to non-essential metallic and metalloid pollutants, including arsenic, lead, and cadmium as well as essential metallic and metalloid contaminants like copper, has been associated with an elevated risk of CVD events and CVD mortality, according to moderate-quality evidence. According to low-quality evidence, exposure to arsenic, lead, and cadmium increases the risk of CHD, while exposure to lead, cadmium, and copper is strongly associated with an increased risk of stroke and all-cause mortality. Further, zinc and selenium may be protective factors for CVD and all-cause mortality.

CONCLUSION

Despite variations in evidence gradients, environmental metallic and metalloid contaminants like arsenic, lead, cadmium, mercury, and copper are linked to CVD events and mortality, whereas zinc and selenium may offer protection.

Oxidised low-density lipoprotein and adverse outcome in patients with acute mild ischaemic stroke or high-risk TIA: a secondary analysis of the INSPIRES randomised clinical trial

BACKGROUND

Research data regarding the correlation between elevated oxidised low-density lipoprotein (oxLDL) cholesterol concentrations and unfavourable clinical outcomes in individuals experiencing minor acute ischaemic cerebrovascular events or transient ischaemic attack (TIA) with presumed atherosclerotic aetiology are still limited.

METHODS

This investigation incorporated a cohort of 5814 participants derived from the Intensive Statin and Antiplatelet Therapy for Acute High-Risk Intracranial or Extracranial Atherosclerosis clinical trial. The core laboratory conducted blinded measurements of baseline plasma oxLDL concentrations. Multivariable Cox regression analyses were employed to assess the correlations between oxLDL levels and adverse clinical events. The principal endpoint for efficacy assessment was defined as the occurrence of stroke within a 90-day follow-up period. Additional secondary endpoints encompassed composite vascular events during the same observation window. The main safety endpoint assessed was the occurrence of bleeding events of moderate to severe intensity.

RESULTS

The final analytical cohort comprised 5814 patients included in the final analysis. The mean age was 63.7±9.6 years, and 36.0% were female. The average concentration of circulating oxLDL was 36.62 µg/dL. Elevated oxLDL concentrations demonstrated a potential correlation with heightened stroke risk (T3 vs T1: HR 1.39, 95% CI 1.04 to 1.85), ischaemic stroke (T3 vs T1: HR 1.31, 95% CI 0.98 to 1.76) and composite vascular events (T3 vs T1: HR 1.36, 95% CI 1.02 to 1.81) within 90 days. An increased concentration of oxLDL demonstrated a significant association with elevated susceptibility to moderate and severe haemorrhagic events (T3 vs T1: HR 3.61, 95% CI 1.26 to 10.34) within 90 days.

CONCLUSION

Increased concentrations of oxLDL demonstrated an independent correlation with both stroke recurrence and the occurrence of moderate-to-severe haemorrhagic events in individuals presenting with acute minor ischaemic stroke or TIA at elevated risk, accompanied by intracranial or extracranial atherosclerotic lesions.

NCOA4 linked to endothelial cell ferritinophagy and ferroptosis:a key regulator aggravate aortic endothelial inflammation and atherosclerosis

Atherosclerosis (AS) is associated with a high incidence of cardiovascular events, yet the mechanisms underlying this association remain unclear. Our previous study found that Atherosclerotic endothelial injury is closely associated with ferroptosis in ApoE-/- mice. Ferroptosis is a novel mode of cell death induced by decreased antioxidant capacity of the organism and accumulation of reactive oxygen species. Nuclear receptor coactivator 4 (NCOA4)-mediated ferritinophagy is an important regulator of sudden ferroptosis in cells. However, the role of NCOA4 in AS and the exact mechanism by which it regulates the ferritinophagy response remain unclear. Herein, we report that NCOA4 expression is elevated in ApoE-/- mice and endothelial cells and is significantly correlated with AS. NCOA4 expression promoted ferroptosis, and was positively correlated with ferritinophagy response. Mechanistically, our findings indicate that LOX-1 is a key upstream target that influences the function of NCOA4. The specific pathway is related to the activation of cGAS-STING signaling to upregulate NCOA4 expression. Moreover, our findings demonstrate the "Gualou-Xiebai" herb pair can regulate LOX-1 to inhibit ferroptosis. Collectively, our results provide evidence of a connection between NCOA4-mediated promotion of AS and suggest that targeting upstream molecules regulating NCOA4 could be a potential therapy for AS.

Atherogenic low-density lipoprotein and cardiovascular risk

PURPOSE OF REVIEW

Despite reductions in low-density lipoprotein (LDL) cholesterol (LDLc), residual cardiovascular risk remains due to factors beyond lipoprotein levels, such as LDL particle count, size, electronegativity and modifications. Technological advances allow detailed profiling of LDL particles, offering potential biomarkers for diagnosis, prognosis, and treatment of cardiovascular disease (CVD). The aim of this review is to provide an updated overview of the state of knowledge in the field of LDL atherosclerotic role, which is evolving rapidly due to technological advances in biomarker measurement and applications.

RECENT FINDINGS

While small dense LDL has been linked to increased CVD risk, current approaches favor a comprehensive evaluation of all lipoprotein subtypes, as this is a more feasible and standardized method. The atherogenic potential of circulating oxidized LDL (oxLDL) may be the key factor in the onset and progression of atherosclerosis. Thus, elevated oxLDL levels are recognized as a marker of increased CVD risk in both general and high-risk populations, although further research is needed to clarify some conflicting findings. The oxidized LDL receptor 1 (LOX-1) has emerged as a promising target for immunotherapy and innovative drug delivery strategies to modulate atherosclerosis.

SUMMARY

A panel of biomarkers related to LDL atherogenicity may help predict future ischemic events. An atheroprotective diet and increased physical activity could improve LDL oxidation. OxLDL has become a target for immunomodulatory antiatherosclerosis therapy and delivering LDL-based nanocarriers holds promise for both imaging and therapeutics.

Interplay of ferroptosis, cuproptosis, and PANoptosis in cancer treatment-induced cardiotoxicity: Mechanisms and therapeutic implications

With the prolonged survival of individuals with cancer, the emergence of cardiovascular diseases (CVD) induced by cancer treatment has become a significant concern, ranking as the second leading cause of death among cancer survivors. This review explores three distinct types of programmed cell death (PCD): ferroptosis, cuproptosis, and PANoptosis, focusing on their roles in chemotherapy-induced cardiotoxicity. While ferroptosis and cuproptosis are triggered by excess iron and copper (Cu), PANoptosis is an inflammatory PCD with features of pyroptosis, apoptosis, and necroptosis. Recent studies reveal intricate connections among these PCD types, emphasizing the interplay between cuproptosis and ferroptosis. Notably, the role of intracellular Cu in promoting ferroptosis through GPX4 is highlighted. Additionally, ROS-induced PANoptosis is influenced by ferroptosis and cuproptosis, suggesting a complex interrelationship. This review provides insights into the molecular mechanisms of these PCD modalities and their distinct contributions to chemotherapy-induced cardiotoxicity. Furthermore, we discuss the potential application of cardioprotective drugs in managing these PCD types. This comprehensive analysis aims to advance the understanding, diagnosis, and therapeutic strategies for cardiotoxicity associated with cancer treatment.

Copper ions: The invisible killer of cardiovascular disease (Review)

Copper, a vital trace element, is indispensable for the maintenance of physiological functioning, particularly in the cardiac system. Unlike other forms of cell death such as iron death and apoptosis, copper‑induced cell death has gained increasing recognition as a significant process influencing the development of cardiovascular diseases. The present review highlights the significance of maintaining copper homeostasis in addressing cardiovascular diseases. This review delves into the crucial roles of copper in physiology, including the metabolic pathways and its absorption, transport and excretion. It provides detailed insights into the mechanisms underlying cardiovascular diseases resulting from both excess and deficient copper levels. Additionally, it summarizes strategies for treating copper imbalances through approaches such as copper chelators and ion carriers while discussing their limitations and future prospects.

Copper redox state in cells and aquatic organisms: Implication for toxicity

Copper (Cu) redox state has been an important issue in biology and toxicology research, but many research gaps remain to be explored due to the limitations in the detecting techniques. Herein, the regulation of Cu homeostasis, including absorption, translocation, utilization, storage, and elimination behavior is discussed. Cuproptosis, a newly identified type of cell death caused by excessive Cu accumulation, which results in the aggregation of DLAT protein or the loss of Fe-S cluster and finally proteotoxic stress, is reviewed. Several longstanding mysteries of diseases such as Wilson disease and toxic effects, may be attributed to cuproptosis. Furthermore, we review the advanced detection methods and application of Cu(I) and Cu(II), especially the in-situ imaging techniques such as XANES, and chemosensors. Most of the existing studies using these detection techniques focus on the bioaccumulation and toxicity of Cu(I) and Cu(II) in cells and aquatic organisms. Finally, it will be important to identify the roles of Cu(I) and Cu(II) in the growth, development, and diseases of organisms, as well as the relationship between bioaccumulation and toxicity of Cu(I) and Cu(II) in cellular and aquatic toxicology.

A Potential Link between Myeloperoxidase Modified LDL, Atherosclerosis and Depression

Atherosclerosis is a chronic inflammatory disease that involves modified low-density lipoproteins (LDL) which play a pivotal role in the initiation and progression of the disease. Myeloperoxidase oxidized LDL (Mox-LDL) is considered to be the most patho-physiologically relevant type of modified LDL and has been reported to be ubiquitously present in atheroma plaques of patients with atherosclerosis. Besides its involvement in the latter disease state, Mox-LDL has also been shown to be implicated in the pathogenesis of various illnesses including sleep disorders, which are in turn associated with heart disease and depression in many intricate ways. Meanwhile, we have recently shown that lox-1-mediated Mox-LDL signaling modulates neuroserpin activity in endothelial cells, which could have major implications that go beyond the pathophysiology of stroke and cerebrovascular disease (CD). Of note is that tissue plasminogen activator (tPA), which is the main target of neuroserpin in the brain, has a crucial function in the processing of brain-derived neurotrophic factor (BDNF) into its mature form. This factor is known to be involved in major depressive disorder (MDD) development and pathogenesis. Since tPA is more conventionally recognized as being involved in fibrinolytic mechanisms, and its effect on the BDNF system in the context of MDD is still not extensively studied, we speculate that any Mox-LDL-driven change in the activity of tPA in patients with atherosclerosis may lead to a decrease in the production of mature BDNF, resulting in impaired neural plasticity and depression. Deciphering the mechanisms of interaction between those factors could help in better understanding the potentially overlapping pathological mechanisms that regulate disease processes in CD and MDD, supporting the possibility of novel and common therapeutic opportunities for millions of patients worldwide.

The in vitro effect of myeloperoxidase oxidized LDL on THP-1 derived macrophages

Cardiovascular diseases (CVDs) linked to atherosclerosis remains the leading cause of death worldwide. Atherosclerosis is primarily caused by the accumulation of oxidized forms of low density lipoprotein (LDL) in macrophages (MΦs) in the subendothelial layer of arteries leading to foam cell and fatty streak formation. Many studies suggest that LDL that is modified by myeloperoxidase (MPO) is a key player in the development of atherosclerosis. MΦs can adopt a variety of functional phenotypes that include mainly the proinflammatory M1 and the anti-inflammatory M2 MΦ phenotypes which are both implicated in the process of atherogenesis. In fact, MΦs that reside in atherosclerostic lesions were shown to express a variety of phenotypes ranging between the M1- and M2 MΦ types. Recently, we pointed out the involvement of MPO oxidized-LDL (Mox-LDL) in increasing inflammation in MΦs by reducing their secretion of IL-10. Since little is known about Mox-LDL-mediated pro-atherosclerostic responses in MΦs, our study aimed at analyzing the in vitro effects of Mox-LDL at this level through making use of the well-established model of human THP-1-derived Mφs. Our results demonstrate that Mox-LDL has no effect on apoptosis, reactive oxygen species (ROS) generation and cell death in our cell model; yet, interestingly, our results show that Mox-LDL is significantly engulfed at a higher rate in the different MΦ subtypes supporting its key role in foam cell formation during the progression of the disease as well as previous data that were generated using another primary MΦ cell model of atherosclerosis.

Sea Buckthorn Polysaccharide Ameliorates Colitis

Ulcerative colitis (UC) is characterized by chronic inflammation and ulceration of the intestinal inner lining, resulting in various symptoms. Sea buckthorn berries contain a bioactive compound known as sea buckthorn polysaccharide (SBP). However, the precise mechanisms underlying the impact of SBP on UC remain unclear. In this study, we investigated the effects of pretreatment with SBP on colitis induced by DSS. Our findings demonstrate that SBP pretreatment effectively reduces inflammation, oxidative stress, and intestinal barrier damage associated with colitis. To further elucidate the role of SBP-modulated gut microbiota in UC, we performed fecal microbiota transplantation (FMT) on DSS-treated mice. The microbiota from SBP-treated mice exhibits notable anti-inflammatory and antioxidant effects, improves colonic barrier integrity, and increases the abundance of beneficial bacteria, as well as enhancing SCFA production. Collectively, these results strongly indicate that SBP-mediated amelioration of colitis is attributed to its impact on the gut microbiota, particularly through the promotion of SCFA-producing bacteria and subsequent elevation of SCFA levels. This study provides compelling evidence supporting the efficacy of pre-emptive SBP supplementation in alleviating colitis symptoms by modulating the gut microbiota, thereby offering novel insights into the potential of SBP as a regulator of the gut microbiota for colitis relief.

Novel Insights into the Link Between Myeloperoxidase Modified LDL, LOX-1, and Neuroserpin in Stroke

Background

Cardiovascular disease that is caused by atherosclerosis is the leading cause of death worldwide. Atherosclerosis is primarily triggered by endothelial dysfunction and the accumulation of modified low-density lipoprotein (LDL) particles in the subendothelial space of blood vessels. Early reports have associated oxidized LDL with altered fibrinolysis and atherogenesis. It has been suggested that myeloperoxidase oxidized LDL (Mox-LDL) is involved in atherosclerosis because of its significant pathophysiological role in the modification of LDL in vivo. It has been equally demonstrated that Mox-LDL binds to the lectin-like oxidized low-density lipoprotein receptor-1 (lox-1) scavenger receptor which leads to the upregulation of inflammatory mediators in endothelial cells and the progression of cardiovascular disease. It has been also shown that neuroserpin, a member of the serine proteinase inhibitor (serpin) superfamily, has an important role at the level of fibrinolysis in the nervous tissue.

Methods

Since little is known about the effects of Mox-LDL on endothelial cell fibrinolytic activity and the involvement of lox-1 in this process, our study aimed at evaluating the in vitro effects of Mox-LDL on neuroserpin release from human aortic endothelial cells (HAECs) and the role of lox-1 scavenger receptor in this context by relying on lox-1 gene silencing in HAECs, culturing the cells in the presence of Mox-LDL, measuring their neuroserpin expression and release by quantitative polymerase chain reaction (qPCR) and enzyme-linked immunosorbent assay (ELISA), respectively, and assessing their fibrinolytic activity using the Euglobulin Clot Lysis Time (ECLT) method.

Results

Our data show that Mox-LDL decreases endothelial cell fibrinolytic capacity by upregulating neuroserpin in lox-1 knockdown cells.

Conclusions

Lox-1 protects the endothelial cells from a Mox-LDL-induced decrease in pro-fibrinolytic capacity, which has important consequences in the context of stroke.

The molecular mechanisms of cuproptosis and its relevance to cardiovascular disease

Recently, cuproptosis has been demonstrated to be a new non-apototic cell death mode that is characterized by copper dependence and the regulation of mitochondrial respiration. Cuproptosis is distinct from known cell death modes such as apoptosis, necrosis, pyroptosis, or ferroptosis. Excessive copper induces cuproptosis by promoting protein toxic stress reactions via copper-dependent anomalous oligomerization of lipoylation proteins in the tricarboxylic acid (TCA) cycle and reducing iron-sulfur cluster protein levels. Ferredoxin1 (FDX1) promotes dihydrolipoyl transacetylase (DLAT) lipoacylation and abates iron-sulfur cluster proteins by reducing Cu²⁺ to Cu⁺, inducing cell death. Copper homeostasis depends on the copper transporter, and disturbances to this homeostasis cause cuproptosis. Recent evidence has shown that cuproptosis plays a significant role in the occurrence and development of many cardiovascular diseases, such as myocardial ischemia/reperfusion (I/R) injury, heart failure, atherosclerosis, and arrhythmias. Copper chelators, such as ammonium tetrathiomolybdate(VI) and DL-Penicillamine, may ease the above cardiovascular diseases by inhibiting the cuproptosis pathway. Oxidative phosphorylation inhibitors may inhibit cuproptosis by inhibiting protein stress response. In conclusion, cuproptosis plays an essential role in cardiovascular disease pathogenesis. Inhibition of cardiovascular cuproptosis is expected to become a potential treatment. Here, we will thoroughly review the molecular mechanisms involved in cuproptosis and its significance in cardiovascular disease.

Role of myeloperoxidase in inflammation and atherosclerosis (Review)

Myeloperoxidase (MPO) belongs to the heme peroxidase family, which includes a set of enzymes with potent oxidoreductase activity. MPO is considered an important part of the innate immune system's microbicidal arm and is secreted by neutrophils and macrophages. Interestingly, this enzyme has been implicated in the pathogenesis of several diseases including atherosclerosis. MPO is ubiquitous in atherosclerotic lesions and contributes to the initiation and progression of the disease primarily by oxidizing low-density lipoprotein (LDL) particles. MPO is the only human enzyme with the ability to produce hypochlorous acid (HOCl) at physiological chloride concentrations and HOCl-LDL epitopes were shown to be present inside atheromatous lesions making it a physiologically relevant model for the oxidation of LDL. It has been shown that MPO modified LDL is not able to bind to the native LDL receptor and is recognized instead by scavenger receptors on both endothelial cells and macrophages, which can lead to endothelial dysfunction and foam cell formation, respectively; both of which are instrumental in the progression of the disease. Meanwhile, several studies have proposed MPO as a biomarker for cardiovascular diseases where high levels of this enzyme were linked to an increased risk of developing coronary artery disease. Overall, there is sufficient evidence supporting the value of MPO as a crucial player in health and disease. Thus, future research should be directed towards investigating the still unknown processes associated with this enzyme. This may assist in better understanding the pathophysiological role of MPO, as well in the development of therapeutic strategies for protecting against the deleterious effects of MPO in numerous pathologies such as atherosclerosis.

Halogenation Activity of Mammalian Heme Peroxidases

Mammalian heme peroxidases are fascinating due to their unique peculiarity of oxidizing (pseudo)halides under physiologically relevant conditions. These proteins are able either to incorporate oxidized halides into substrates adjacent to the active site or to generate different oxidized (pseudo)halogenated species, which can take part in multiple (pseudo)halogenation and oxidation reactions with cell and tissue constituents. The present article reviews basic biochemical and redox mechanisms of (pseudo)halogenation activity as well as the physiological role of heme peroxidases. Thyroid peroxidase and peroxidasin are key enzymes for thyroid hormone synthesis and the formation of functional cross-links in collagen IV during basement membrane formation. Special attention is directed to the properties, enzymatic mechanisms, and resulting (pseudo)halogenated products of the immunologically relevant proteins such as myeloperoxidase, eosinophil peroxidase, and lactoperoxidase. The potential role of the (pseudo)halogenated products (hypochlorous acid, hypobromous acid, hypothiocyanite, and cyanate) of these three heme peroxidases is further discussed.

Unexpected Role of MPO-Oxidized LDLs in Atherosclerosis: In between Inflammation and Its Resolution

Inflammation and its resolution are the result of the balance between pro-inflammatory and pro-resolving factors, such as specialized pro-resolving mediators (SPMs). This balance is crucial for plaque evolution in atherosclerosis, a chronic inflammatory disease. Myeloperoxidase (MPO) has been related to oxidative stress and atherosclerosis, and MPO-oxidized low-density lipoproteins (Mox-LDLs) have specific characteristics and effects. They participate in foam cell formation and cause specific reactions when interacting with macrophages and endothelial cells. They also increase the production of intracellular reactive oxygen species (ROS) in macrophages and the resulting antioxidant response. Mox-LDLs also drive macrophage polarization. Mox-LDLs are known to be pro-inflammatory particles. However, in the presence of Mox-LDLs, endothelial cells produce resolvin D1 (RvD1), a SPM. SPMs are involved in the resolution of inflammation by stimulating efferocytosis and by reducing the adhesion and recruitment of neutrophils and monocytes. RvD1 also induces the synthesis of other SPMs. In vitro, Mox-LDLs have a dual effect by promoting RvD1 release and inducing a more anti-inflammatory phenotype macrophage, thereby having a mixed effect on inflammation. In this review, we discuss the interrelationship between MPO, Mox-LDLs, and resolvins, highlighting a new perception of the role of Mox-LDLs in atherosclerosis.