The Role of Glycocalyx and Caveolae in Vascular Homeostasis and Diseases

Assessing coagulopathy and endothelial dysfunction in pediatric venous malformation: A thromboelastometry and syndecan-1 study

OBJECTIVE

The occurrence of unpredictable pain crises are the principal determinant of the quality of life for patients with venous malformations (VM). A definite coagulation phenomenon, characterized by an increase in D-dimer levels and the presence of phleboliths within the malformation, has been previously reported. By applying Virchow's triad and evaluating intralesional samples, our objective is to delineate the coagulation profile and the extent of endothelial dysfunction within the malformation.

METHODS

With the authorization of the Ethics Committee, a research project was undertaken on intralesional and extralesional blood samples from 30 pediatric patients afflicted with spongiform VM. Thromboelastometry analyses were performed using ROTEM Sigma, and the concentration of syndecan-1 was determined by ELISA.

RESULTS

In the ROTEM analyses, the A5, A10, and maximum clot firmness (MCF) values were below the established reference ranges in the intralesional samples in both the EXTEM and INTEM assays, indicating that intralesional clots had significant instability. Furthermore, during the investigation of the delayed fibrinolysis phase using recombinant tissue plasminogen activator (rtPA) in EXTEM analysis, widespread hyperfibrinolysis was observed intralesional. Additionally, analysis of syndecan-1 showed significant differences between extralesional and intralesional levels (p < .026) and controls (p < .03), suggesting differences in the state of endothelium.

CONCLUSIONS

For the first time, we developed a comprehensive understanding of the coagulopathic profile of VM and the role of endothelial dysfunction in its pathogenesis. These findings will enable the implementation of targeted therapies based on the individual coagulation profiles.

Biomechanics-mediated endocytosis in atherosclerosis

Biomechanical forces, including vascular shear stress, cyclic stretching, and extracellular matrix stiffness, which influence mechanosensitive channels in the plasma membrane, determine cell function in atherosclerosis. Being highly associated with the formation of atherosclerotic plaques, endocytosis is the key point in molecule and macromolecule trafficking, which plays an important role in lipid transportation. The process of endocytosis relies on the mobility and tension of the plasma membrane, which is sensitive to biomechanical forces. Several studies have advanced the signal transduction between endocytosis and biomechanics to elaborate the developmental role of atherosclerosis. Meanwhile, increased plaque growth also results in changes in the structure, composition and morphology of the coronary artery that contribute to the alteration of arterial biomechanics. These cross-links of biomechanics and endocytosis in atherosclerotic plaques play an important role in cell function, such as cell phenotype switching, foam cell formation, and lipoprotein transportation. We propose that biomechanical force activates the endocytosis of vascular cells and plays an important role in the development of atherosclerosis.

The potential effect of natural antioxidants on endothelial dysfunction associated with arterial hypertension

Arterial hypertension represents a leading cause of cardiovascular morbidity and mortality worldwide, and the identification of effective solutions for treating the early stages of elevated blood pressure (BP) is still a relevant issue for cardiovascular risk prevention. The pathophysiological basis for the occurrence of elevated BP and the onset of arterial hypertension have been widely studied in recent years. In addition, consistent progress in the development of novel, powerful, antihypertensive drugs and their appropriate applications in controlling BP have increased our potential for successfully managing disease states characterized by abnormal blood pressure. However, the mechanisms responsible for the disruption of endogenous mechanisms contributing to the maintenance of BP within a normal range are yet to be fully clarified. Recently, evidence has shown that several natural antioxidants containing active ingredients originating from natural plant extracts, used alone or in combination, may represent a valid solution for counteracting the development of arterial hypertension. In particular, there is evidence to show that natural antioxidants may enhance the viability of endothelial cells undergoing oxidative damage, an effect that could play a crucial role in the pathophysiological events accompanying the early stages of arterial hypertension. The present review aims to reassess the role of oxidative stress on endothelial dysfunction in the onset and progression of arterial hypertension and that of natural antioxidants in covering several unmet needs in the treatment of such diseases.

Impact of estimated plasma volume status on clinical outcomes in patients with lower extremity artery disease who underwent endovascular therapy

Lower extremity artery disease (LEAD) is an arterial occlusive disease associated with high morbidity and mortality. Estimated plasma volume status (ePVS), a marker of plasma volume expansion and contraction, is gaining attention in the field of cardiovascular diseases. However, the impact of ePVS on the clinical outcomes of patients with LEAD remains unclear. We calculated ePVS using two different formulas, Kaplan-Hakim (KH-ePVS) and Duarte (D-ePVS), in 288 patients (mean age, 73 years; 77% male) with LEAD who underwent the first endovascular therapy (EVT), and prospectively followed them up between 2014 and 2019. All patients were divided into two groups based on the median ePVS values. The primary endpoints were composite events, including all-cause death and major adverse limb events (death/MALE). The median follow-up duration was 672 days. There were 183, 40 and 65 patients in Fontaine classes II, III, and IV, respectively. The median KH-ePVS and D-ePVS was 5.96 and 5.09, respectively. The ePVS significantly increased with advancing Fontaine classes. Kaplan-Meier analysis demonstrated that the high ePVS group had higher rates of death/MALE than the low ePVS group. Multivariate Cox proportional hazard analysis revealed that each ePVS was an independent predictor for death/MALE after adjusting for confounding risk factors. The prognostic ability for death/MALE was significantly improved by adding ePVS to the basic predictors. ePVS was associated with LEAD severity and clinical outcomes, suggesting that ePVS could be an additional risk factor for death/MALE in patients with LEAD who underwent EVT. We demonstrated that the association between ePVS and the clinical outcomes of patients with LEAD. The prognostic ability for death/MALE was significantly improved by adding ePVS to the basic predictors. LEAD lower extremity artery disease, MALE major adverse limb events, PVS plasma volume status.

ADAM10-a "multitasker" in sepsis: focus on its posttranslational target

BACKGROUND

Sepsis has a complex pathogenesis in which the uncontrolled systemic inflammatory response triggered by infection leads to vascular barrier disruption, microcirculation dysfunction and multiple organ dysfunction syndrome. Numerous recent studies reveal that a disintegrin and metalloproteinase 10 (ADAM10) acts as a "molecular scissor" playing a pivotal role in the inflammatory response during sepsis by regulating proteolysis by cleaving various membrane protein substrates, including proinflammatory cytokines, cadherins and Notch, which are involved in intercellular communication. ADAM10 can also act as the cellular receptor for Staphylococcus aureus α-toxin, leading to lethal sepsis. However, its substrate-specific modulation and precise targets in sepsis have not yet to be elucidated.

METHODS

We performed a computer-based online search using PubMed and Google Scholar for published articles concerning ADAM10 and sepsis.

CONCLUSIONS

In this review, we focus on the functions of ADAM10 in sepsis-related complex endothelium-immune cell interactions and microcirculation dysfunction through the diversity of its substrates and its enzymatic activity. In addition, we highlight the posttranslational mechanisms of ADAM10 at specific subcellular sites, or in multimolecular complexes, which will provide the insight to intervene in the pathophysiological process of sepsis caused by ADAM10 dysregulation.

Caveolin-1 inhibition mediates the opposing effects of alcohol on γ-secretase activity in arterial endothelial and smooth muscle cells

Notch is important to vessel homeostasis. We investigated the mechanistic role of caveolin-1 (Cav-1) in mediating the effects of alcohol (Ethanol/EtOH) on the γ-secretase proteolytic activity necessary for Notch signaling in vascular cells. Human coronary artery endothelial cells (HCAEC) were treated with EtOH (0-50 mM), Notch ligand delta-like ligand 4 (Dll4), and the γ-secretase inhibitor DAPT. EtOH stimulated Notch signaling in HCAEC as evidenced by increased Notch receptor (N1, N4) and target gene (hrt2, hrt3) mRNA levels with the most robust response achieved at 25 mM EtOH. Ethanol (25 mM) stimulated γ-secretase proteolytic activity, to the same extent as Dll4, in HCAEC membranes. Ethanol inhibited Cav-1 mRNA and protein levels in HCAEC. Caveolin-1 negatively regulated γ-secretase activity in HCAEC as Cav-1 knockdown stimulated it, while Cav-1 overexpression inhibited it. Moreover, Cav-1 overexpression blocked the stimulatory effect of EtOH on γ-secretase activity in HCAEC. Although EtOH also inhibited Cav-1 expression in human coronary artery smooth muscle cells (HCASMC), EtOH inhibited γ-secretase activity in HCASMC in contrast to its effect in HCAEC. The inhibitory effect of EtOH on γ-secretase in HCASMC was mimicked by Cav-1 knockdown and prevented by Cav-1 overexpression, suggesting that in these cells Cav-1 positively regulates γ-secretase activity. In conclusion, EtOH differentially regulates γ-secretase activity in arterial EC and SMC, being stimulatory and inhibitory, respectively. These effects are both mediated by caveolin-1 inhibition which itself has opposite effects on γ-secretase in the two cell types. This mechanism may underlie, in part, the effects of moderate drinking on atherosclerosis.

Acute Exposure to Glycated Proteins Impaired in the Endothelium-Dependent Aortic Relaxation: A Matter of Oxidative Stress

Chronically increased levels of high molecular weight advanced glycation end products (HMW-AGEs) are known to induce cardiovascular dysfunction. Whether an acute increase in HMW-AGE levels affects vascular function remains unknown. In this study, we examined whether acute exposure to HMW-AGEs disturbs aortic vasomotor function. Aortae were obtained from healthy male rats and were acutely pre-treated with HMW-AGEs in organ baths. Aortic relaxation responses to cumulative doses of acetylcholine (ACh), in the presence or absence of superoxide dismutase (SOD), were measured after precontraction with phenylephrine (PE). Furthermore, levels of 3-nitrotyrosine were evaluated on aortic paraffine sections. In our study, we show that acute exposure to HMW-AGEs significantly decreases the aortic relaxation response to ACh. SOD pre-treatment prevents acute HMW-AGEs-induced impairment by limiting superoxide formation. In conclusion, our data demonstrate that acute exposure to HMW-AGEs causes adverse vascular remodelling, characterised by disturbed vasomotor function due to increased oxidative stress. These results create opportunities for future research regarding the acute role of HMW-AGEs in cardiovascular dysfunction.

Assessing cardiovascular disease: looking beyond cholesterol

PURPOSE OF REVIEW

The low-density lipoprotein (LDL)-cholesterol level is a weak predictor of developing cardiovascular (CV) disease and can only explain a small proportion of CV risk. It is not used to determine CV risk on either the atherosclerotic cardiovascular disease (ASCVD) calculator in the United States, or the Qrisk3 in the UK.A study in JAMA in 2022 suggested that ' the absolute benefits of statins are modest and may not be strongly mediated through the degree of LDL reduction '. Perhaps it is time to look beyond cholesterol to a different causal model - the 'thrombogenic' model of ASCVD.

RECENT FINDINGS

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV2) pandemic demonstrated that infectious agents damage the endothelium and the glycocalyx - the glycoprotein layer protecting underlying endothelial cells. There are numerous other conditions leading to this kind of damage, which can trigger thrombus formation, causing strokes and myocardial infarctions.Although these are acute events, they highlight a mechanism for the development of ASCVD which centres on endothelial damage and thrombus formation as both the primary causal mechanism for acute events, and the driver behind progression towards atherosclerotic plaque development.

SUMMARY

The cholesterol hypothesis, that a raised LDL is directly causal for ASCVD, does not adequately explain cardiovascular risk in individuals, or populations. An alternative 'thrombogenic' hypothesis is proposed as a more valid causal model.

Neuraminidases-Key Players in the Inflammatory Response after Pathophysiological Cardiac Stress and Potential New Therapeutic Targets in Cardiac Disease

Glycoproteins and glycolipids on the cell surfaces of vertebrates and higher invertebrates contain α-keto acid sugars called sialic acids, terminally attached to their glycan structures. The actual level of sialylation, regulated through enzymatic removal of the latter ones by NEU enzymes, highly affects protein-protein, cell-matrix and cell-cell interactions. Thus, their regulatory features affect a large number of different cell types, including those of the immune system. Research regarding NEUs within heart and vessels provides new insights of their involvement in the development of cardiovascular pathologies and identifies mechanisms on how inhibiting NEU enzymes can have a beneficial effect on cardiac remodelling and on a number of different cardiac diseases including CMs and atherosclerosis. In this regard, a multitude of clinical studies demonstrated the potential of N-acetylneuraminic acid (Neu5Ac) to serve as a biomarker following cardiac diseases. Anti-influenza drugs i.e., zanamivir and oseltamivir are viral NEU inhibitors, thus, they block the enzymatic activity of NEUs. When considering the improvement in cardiac function in several different cardiac disease animal models, which results from NEU reduction, the inhibition of NEU enzymes provides a new potential therapeutic treatment strategy to treat cardiac inflammatory pathologies, and thus, administrate cardioprotection.

Empagliflozin mitigates endothelial inflammation and attenuates endoplasmic reticulum stress signaling caused by sustained glycocalyx disruption

The disruption of the endothelial cell (EC) glycocalyx (GCX) leads to cellular dysfunction promoting inflammation and cardiovascular disease progression. Recent studies have shown that empagliflozin (EMPA; Jardiance), a sodium-glucose cotransporter 2 inhibitor used in the treatment of type 2 diabetes, can improve EC functions impacted by GCX disruption although the exact cellular mechanisms remain to be elucidated. In this study, the effect of EMPA on EC inflammatory response induced by sustained GCX disruption was investigated. Human aortic ECs were cultured under shear (10 dyne/cm²) for 24 h with or without sustained degradation of heparan sulfate (HS). HS degradation increased inflammatory cell adhesion to ECs. EMPA (50 μM) normalized adhesion levels under sustained HS degradation. Protein expressions of eNOS, phospho-eNOS Ser1177 and ICAM-1 remained unchanged between conditions. Transcriptome analysis revealed the induction of the unfolded protein response (UPR) through the increased expression of ATF3, ATF4, DDIT3 (CHOP), EIF2AK3 (PERK), HSPA5 (Grp78), PPP1R15A (GADD34) and TRIB3 which was in part downregulated by EMPA. mRNA and protein expression of thioredoxin interacting protein (TXNIP) was also downregulated by EMPA. Mitigation of oxidative stress with N-Acetyl-L-cysteine resulted in similar reduction in inflammatory cell adhesion compared to EMPA which could indicate a potential mechanism by which EMPA normalized the inflammatory response. In conclusion, this study demonstrated the potential of EMPA to resolve the inflammatory response of ECs caused by sustained GCX disruption while altering UPR signaling under endoplasmic reticulum stress.

Deciphering the relationship between caveolae-mediated intracellular transport and signalling events

The caveolae-mediated transport across polarized epithelial cell barriers has been largely deciphered in the last decades and is considered the second essential intracellular transfer mechanism, after the clathrin-dependent endocytosis. The basic cell biology knowledge was supplemented recently, with the molecular mechanisms beyond caveolae generation implying the key contribution of the lipid-binding proteins (the structural protein Caveolin and the adapter protein Cavin), along with the bulb coat stabilizing molecules PACSIN-2 and Eps15 homology domain protein-2. The current attention is focused also on caveolae architecture (such as the bulb coat, the neck, the membrane funnel inside the bulb, and the associated receptors), and their specific tasks during the intracellular transport of various cargoes. Here, we resume the present understanding of the assembly, detachment, and internalization of caveolae from the plasma membrane lipid raft domains, and give an updated view on transcytosis and endocytosis, the two itineraries of cargoes transport via caveolae. The review adds novel data on the signalling molecules regulating caveolae intracellular routes and on the transport dysregulation in diseases. The therapeutic possibilities offered by exploitation of Caveolin-1 expression and caveolae trafficking, and the urgent issues to be uncovered conclude the review.

The Endothelium as a Hub for Cellular Communication in Atherogenesis: Is There Directionality to the Message?

Endothelial cells line every blood vessel and thereby serve as an interface between the blood and the vessel wall. They have critical functions for maintaining homeostasis and orchestrating vascular pathogenesis. Atherosclerosis is a chronic disease where cholesterol and inflammatory cells accumulate in the artery wall below the endothelial layer and ultimately form plaques that can either progress to occlude the lumen or rupture with thromboembolic consequences – common outcomes being myocardial infarction and stroke. Cellular communication lies at the core of this process. In this review, we discuss traditional (e.g., cytokines, chemokines, nitric oxide) and novel (e.g., extracellular vesicles) modes of endothelial communication with other endothelial cells as well as circulating and vessel wall cells, including monocytes, macrophages, neutrophils, vascular smooth muscle cells and other immune cells, in the context of atherosclerosis. More recently, the growing appreciation of endothelial cell plasticity during atherogenesis suggests that communication strategies are not static. Here, emerging data on transcriptomics in cells during the development of atherosclerosis are considered in the context of how this might inform altered cell-cell communication. Given the unique position of the endothelium as a boundary layer that is activated in regions overlying vascular inflammation and atherosclerotic plaque, there is a potential to exploit the unique features of this group of cells to deliver therapeutics that target the cellular crosstalk at the core of atherosclerotic disease. Data are discussed supporting this concept, as well as inherent pitfalls. Finally, we briefly review the literature for other regions of the body (e.g., gut epithelium) where cells similarly exist as a boundary layer but provide discrete messages to each compartment to govern homeostasis and disease. In this light, the potential for endothelial cells to communicate in a directional manner is explored, along with the implications of this concept – from fundamental experimental design to biomarker potential and therapeutic targets.

Albumin, Oral Contraceptives, and Venous Thromboembolism Risk in Astronauts

BACKGROUND

A venous thromboembolism (VTE) event occurred in a female astronaut during long-duration spaceflight. Multiple factors may have contributed to this risk, including the use of combined (progestin + estrogen) oral contraceptives (cOC).

METHODS

Biochemistry data from 65 astronauts were evaluated for associations with cOC use and with sex.

RESULTS

The female astronauts who used cOCs had lower concentrations of serum albumin and higher concentrations of transferrin, a protein involved in the clotting cascade, than the male astronauts and the female astronauts who were not taking cOCs (P<0.001). The women who used cOCs had higher serum concentrations of the acute phase reactant ceruloplasmin during flight and cortisol (P<0.001) than the men and the women who were not taking cOCs; they also had higher calculated whole blood viscosity than women not taking cOCs (P<0.001).

CONCLUSIONS

Lower circulating concentrations of albumin, higher concentrations of transferrin, and elevated markers of inflammation all could contribute to an increased risk of VTE during spaceflight. These changes, in association with a higher blood viscosity can directly affect endothelial glycocalyx integrity and hypercoagulability status, both of which contribute to VTE risk in terrestrial populations.

Maternal Vascular Lesions in the Placenta Predict Vascular Impairments a Decade After Delivery

Women with adverse pregnancy outcomes later experience excess hypertension and cardiovascular disease, but how the events are linked is unknown. Examination of the placenta may provide clues to vascular impairments after delivery. Maternal vascular malperfusion lesions (MVMs) were abstracted from clinical reports, validated and characterized using clinical guidelines and severity score. A total of 492 women (170 with MVMs and 322 without MVMs) participated in a study visit 8 to 10 years after delivery to assess blood pressure, cardiometabolic factors, and sublingual microvascular features using sidestream dark field imaging. Covariates included age, race, adverse pregnancy outcomes (preeclampsia, small for gestational age, and preterm birth), and health behaviors. Women with versus without MVM had a distinct sublingual microvascular profile comprised of (1) lower microvascular density (-410 μm/mm², P=0.015), (2) higher red blood cell filling as a marker of perfusion (2%, P=0.004), and (3) smaller perfused boundary region (-0.07 µm, P=0.025) as a measure of glycocalyx integrity, adjusted for covariates including adverse pregnancy outcomes. Women with MVM also had higher adjusted diastolic blood pressure (+2.6 mm Hg, P=0.021), total and LDL (low-density lipoprotein)-cholesterol (+11.2 mg/dL, P=0.016; +8.7 mg/dL, P=0.031). MVM associations with subsequent cardiovascular measures did not vary by type of adverse pregnancy outcome, except among women with preterm births where blood pressure was higher only among those with MVM. Results were similar when evaluated as MVM severity. A decade after delivery, women with placental vascular lesions had an adverse cardiovascular profile comprised of microvascular rarefaction, higher blood pressure and more atherogenic lipids. Placental histopathology may reveal a woman's early trajectory toward subsequent vascular disease.

A study of lovastatin and L-arginine co-loaded PLGA nanomedicine for enhancing nitric oxide production and eNOS expression

Nitric oxide (NO) is an exceptional endogenous biological gas that mediates and regulates physiological and pathological processes in the human body. However, its synthesis process is impaired during athero-progression and formation. Hence, a strategy to boost NO production and target endothelial nitric oxide synthase (eNOS) is crucial and intriguing in atherosclerosis (AS) management. Herein, we prepare L-arginine (LA) and lovastatin (LV) co-loaded PLGA nanomedicine to achieve sustainable release for enhancing NO production. The utilization of LA reveals that LA has dual contributions, acting as a NO donor and enhancing the solubility of LV by stabilizing PLGA NPs. PLGA-LA/LV demonstrated its potential to boost NO in vitro and in vivo confirmed using DAF-FM DA, augment eNOS and p-eNOS mRNA and protein levels, and suppress the ki67 proliferation marker in VSMCs; in addition, it lowers the total cholesterol level of blood plasma in C57BL/6 mice. Moreover, PLGA can protect the compound delivered and enhance the bioavailability to reach and get released in the blood circulation after oral administration. Collectively, our results endow a safe and efficient nanomedicine outcome, specifically with potential for AS management.

The protective role of neuronal nitric oxide synthase in endothelial vasodilation in chronic β-adrenoceptor overstimulation

AIMS

Nitric oxide synthases (NOSs) are key enzymes regulating vascular function. Previously, we reported that β-adrenergic (β-AR) overstimulation, a common feature of cardiovascular diseases, did not impair endothelium-dependent vasodilation, although it resulted in endothelial NOS (eNOS) uncoupling and reduced NO bioavailability. In addition to NO, neuronal NOS (nNOS) produces H₂O₂, which contributes to vasodilation. However, there is limited information regarding vascular β-AR signaling and nNOS. In the present study, we assessed the possible role of nNOS-derived H₂O₂ and caveolins on endothelial vasodilation function following β-AR overstimulation.

MAIN METHODS

Male C57BL/6 wild-type and nNOS knockout mice (nNOS^-/-) were treated with the β-AR agonist isoproterenol (ISO, 15 mg·kg^-1·day^-1, s.c.) or vehicle (VHE) for seven days. Relaxation responses of aortic rings were evaluated using wire myograph and H₂O₂ by Amplex Red.

KEY FINDINGS

Acetylcholine- or calcium ionophore A23187-induced endothelium-dependent relaxation was similar in aortic rings from VHE and ISO. However, this relaxation was significantly reduced in aortas from ISO compared to VHE when (1) caveolae were disrupted, (2) nNOS was pharmacologically inhibited or genetically suppressed and (3) H₂O₂ was scavenged. NOS-derived H₂O₂ production was higher in the aortas of ISO mice than in those of VHE mice. Aortas from ISO-treated mice showed increased expression of caveolin-1, nNOS and catalase, while caveolin-3 expression did not change.

SIGNIFICANCE

The results suggest a role of caveolin-1 and the nNOS/H₂O₂ vasodilatory pathway in endothelium-dependent relaxation following β-AR overstimulation and reinforce the protective role of nNOS in cardiovascular diseases associated with high adrenergic tone.

COVID-19: A Redox Disease-What a Stress Pandemic Can Teach Us About Resilience and What We May Learn from the Reactive Species Interactome About Its Treatment

Significance: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus causing coronavirus disease 2019 (COVID-19), affects every aspect of human life by challenging bodily, socioeconomic, and political systems at unprecedented levels. As vaccines become available, their distribution, safety, and efficacy against emerging variants remain uncertain, and specific treatments are lacking. Recent Advances: Initially affecting the lungs, COVID-19 is a complex multisystems disease that disturbs the whole-body redox balance and can be long-lasting (Long-COVID). Numerous risk factors have been identified, but the reasons for variations in susceptibility to infection, disease severity, and outcome are poorly understood. The reactive species interactome (RSI) was recently introduced as a framework to conceptualize how cells and whole organisms sense, integrate, and accommodate stress. Critical Issues: We here consider COVID-19 as a redox disease, offering a holistic perspective of its effects on the human body, considering the vulnerability of complex interconnected systems with multiorgan/multilevel interdependencies. Host/viral glycan interactions underpin SARS-CoV-2's extraordinary efficiency in gaining cellular access, crossing the epithelial/endothelial barrier to spread along the vascular/lymphatic endothelium, and evading antiviral/antioxidant defences. An inflammation-driven "oxidative storm" alters the redox landscape, eliciting epithelial, endothelial, mitochondrial, metabolic, and immune dysfunction, and coagulopathy. Concomitantly reduced nitric oxide availability renders the sulfur-based redox circuitry vulnerable to oxidation, with eventual catastrophic failure in redox communication/regulation. Host nutrient limitations are crucial determinants of resilience at the individual and population level. Future Directions: While inflicting considerable damage to health and well-being, COVID-19 may provide the ultimate testing ground to improve the diagnosis and treatment of redox-related stress diseases. "Redox phenotyping" of patients to characterize whole-body RSI status as the disease progresses may inform new therapeutic approaches to regain redox balance, reduce mortality in COVID-19 and other redox diseases, and provide opportunities to tackle Long-COVID. Antioxid. Redox Signal. 35, 1226-1268.

Update on the Role of the Endothelial Glycocalyx in Angiogenesis and Vascular Inflammation

The endothelial glycocalyx is a negatively charged, carbohydrate-rich structure that arises from the luminal surface of the vascular endothelium and is comprised of proteoglycans, glycoproteins, and glycolipids. The glycocalyx, which sits at the interface between the endothelium and the blood, is involved in a wide array of physiological and pathophysiological processes, including as a mechanotransducer and as a regulator of inflammation. Most recently, components of the glycocalyx have been shown to play a key role in controlling angiogenesis. In this review, we briefly summarize the structure and function of the endothelial glycocalyx. We focus on its role and functions in vascular inflammation and angiogenesis and discuss the important unanswered questions in this field.

The SARS-CoV-2/Receptor Axis in Heart and Blood Vessels: A Crisp Update on COVID-19 Disease with Cardiovascular Complications

The SARS-CoV-2 virus causing COVID-19 disease has emerged expeditiously in the world and has been declared pandemic since March 2020, by World Health Organization (WHO). The destructive effects of SARS-CoV-2 infection are increased among the patients with pre-existing chronic conditions and, in particular, this review focuses on patients with underlying cardiovascular complications. The expression pattern and potential functions of SARS-CoV-2 binding receptors and the attributes of SARS-CoV-2 virus tropism in a physio-pathological state of heart and blood vessel are precisely described. Of note, the atheroprotective role of ACE2 receptors is reviewed. A detailed description of the possible detrimental role of SARS-CoV-2 infection in terms of vascular leakage, including endothelial glycocalyx dysfunction and bradykinin 1 receptor stimulation is concisely stated. Furthermore, the potential molecular mechanisms underlying SARS-CoV-2 induced clot formation in association with host defense components, including activation of FXIIa, complements and platelets, endothelial dysfunction, immune cell responses with cytokine-mediated action are well elaborated. Moreover, a brief clinical update on patient with COVID-19 disease with underlying cardiovascular complications and those who had new onset of cardiovascular complications post-COVID-19 disease was also discussed. Taken together, this review provides an overview of the mechanistic aspects of SARS-CoV-2 induced devastating effects, in vital organs such as the heart and vessels.

HA and HS Changes in Endothelial Inflammatory Activation

Cardiovascular diseases are a group of disorders caused by the presence of a combination of risk factors, such as tobacco use, unhealthy diet and obesity, physical inactivity, etc., which cause the modification of the composition of the vessel’s matrix and lead to the alteration of blood flow, matched with an inflammation condition. Nevertheless, it is not clear if the inflammation is a permissive condition or a consequent one. In order to investigate the effect of inflammation on the onset of vascular disease, we treated endothelial cells with the cytokine TNF-α that is increased in obese patients and is reported to induce cardiometabolic diseases. The inflammation induced a large change in the extracellular matrix, increasing the pericellular hyaluronan and altering the heparan sulfate Syndecans sets, which seems to be related to layer permeability but does not influence cell proliferation or migration nor induce blood cell recruitment or activation.