Aging enhances the sensitivity of endothelial cells toward apoptotic stimuli: important role of nitric oxide

Aging-regulated PNUTS maintains endothelial barrier function via SEMA3B suppression

Age-related diseases pose great challenges to health care systems worldwide. During aging, endothelial senescence increases the risk for cardiovascular disease. Recently, it was described that Phosphatase 1 Nuclear Targeting Subunit (PNUTS) has a central role in cardiomyocyte aging and homeostasis. Here, we determine the role of PNUTS in endothelial cell aging. We confirm that PNUTS is repressed in senescent endothelial cells (ECs). Moreover, PNUTS silencing elicits several of the hallmarks of endothelial aging: senescence, reduced angiogenesis and loss of barrier function. Findings are validate in vivo using endothelial-specific inducible PNUTS-deficient mice (Cdh5-CreERT2;PNUTSfl/fl), termed PNUTSEC-KO. Two weeks after PNUTS deletion, PNUTSEC-KO mice present severe multiorgan failure and vascular leakage. Transcriptomic analysis of PNUTS-silenced HUVECs and lungs of PNUTSEC-KO mice reveal that the PNUTS-PP1 axis tightly regulates the expression of semaphorin 3B (SEMA3B). Indeed, silencing of SEMA3B completely restores barrier function after PNUTS loss-of-function. These results reveal a pivotal role for PNUTS in endothelial homeostasis through a SEMA3B downstream pathway that provides a potential target against the effects of aging in ECs.

Roles of Protein S-Nitrosylation in Endothelial Homeostasis and Dysfunction

Significance: Nitric oxide (NO) plays several distinct roles in endothelial homeostasis. Except for activating the guanylyl cyclase enzyme-dependent cyclic guanosine monophosphate signaling pathway, NO can bind reactive cysteine residues in target proteins, a process known as S-nitrosylation (SNO). SNO is proposed to explain the multiple biological functions of NO in the endothelium. Investigating the targets and mechanism of protein SNO in endothelial cells (ECs) can provide new strategies for treating endothelial dysfunction-related diseases. Recent Advances: In response to different environments, proteomics has identified multiple SNO targets in ECs. Functional studies confirm that SNO regulates NO bioavailability, inflammation, permeability, oxidative stress, mitochondrial function, and insulin sensitivity in ECs. It also influences EC proliferation, migration, apoptosis, and transdifferentiation. Critical Issues: Single-cell transcriptomic analysis of ECs isolated from different mouse tissues showed heterogeneous gene signatures. However, litter research focuses on the heterogeneous properties of SNO proteins in ECs derived from different tissues. Although metabolism reprogramming plays a vital role in endothelial functions, little is known about how protein SNO regulates metabolism reprogramming in ECs. Future Directions: Precisely deciphering the effects of protein SNO in ECs isolated from different tissues under different conditions is necessary to further characterize the relationship between protein SNO and endothelial dysfunction-related diseases. In addition, identifying SNO targets that can influence endothelial metabolic reprogramming and the underlying mechanism can offer new views on the crosstalk between metabolism and post-translational protein modification. Antioxid. Redox Signal. 40, 186-205.

Expression of insulin-like growth factor binding protein-3 in HELLP syndrome

OBJECTIVE

To investigate the expression of insulin-like growth factor binding protein-3(IGFBP-3) in HELLP syndrome and its possible role in the pathogenesis of this disease.

METHODS

1) 87 subjects were enrolled, including 29 patients with HELLP syndrome, 29 patients with pre-eclampsia (PE), and 29 healthy gravidae as control. The levels of IGFBP-3, IGF-1, TGF-β1, and VEGF in maternal and umbilical blood of them were detected using ELISA. Correlation analysis was used to observe the correlation between IGFBP-3 and IGF-1/TGF-β1/VEGF in maternal and umbilical blood, as well as that between maternal serum IGFBP-3 and clinical diagnostic indicators of HELLP syndrome. 2) Human hepatic sinusoid endothelial cells (HLSEC) and human umbilical vein endothelial cells (HUVEC) were cultured with different concentrations of IGFBP-3. After 72 h of culture, cell apoptosis and the normal living cells rate were detected and compared.

RESULTS

1) In both maternal and umbilical blood of HELLP group, levels of IGFBP-3 and TGF-β1 were higher than control and PE group, IGF-1was lower than control group, VEGF was lower than control and PE group. IGFBP-3 in maternal blood was correlated with IGF-1/TGF-β1/ VEGF, while IGFBP-3 in umbilical blood was linked to IGF-1/TGF-β1. In maternal blood, there was a negative correlation between PLT and IGFBP-3, and a positive correlation between ALT/AST/LDH and IGFBP-3. 2) After cultured with IGFBP-3, the total apoptosis rate of either HLSEC or HUVEC was considerably elevated, while the normal living rate was decreased.

CONCLUSION

The expression of IGFBP-3 is elevated in HELLP syndrome, which may subsequently promote cell apoptosis by affecting the expression and function of IGF-1, VEGF, and TGFβ1 in the IGF/PI3K/Akt, TGF-β1/Smad3, and VEGF/eNOS/NO pathways. IGFBP-3 aggravates inflammatory reactions of the vascular endothelium and liver under hypoxia, affects the normal function of cells, and plays a role in the pathogenesis of diseases.

The Role of Methionine-Rich Diet in Unhealthy Cerebrovascular and Brain Aging: Mechanisms and Implications for Cognitive Impairment

As aging societies in the western world face a growing prevalence of vascular cognitive impairment and Alzheimer's disease (AD), understanding their underlying causes and associated risk factors becomes increasingly critical. A salient concern in the western dietary context is the high consumption of methionine-rich foods such as red meat. The present review delves into the impact of this methionine-heavy diet and the resultant hyperhomocysteinemia on accelerated cerebrovascular and brain aging, emphasizing their potential roles in cognitive impairment. Through a comprehensive exploration of existing evidence, a link between high methionine intake and hyperhomocysteinemia and oxidative stress, mitochondrial dysfunction, inflammation, and accelerated epigenetic aging is drawn. Moreover, the microvascular determinants of cognitive deterioration, including endothelial dysfunction, reduced cerebral blood flow, microvascular rarefaction, impaired neurovascular coupling, and blood-brain barrier (BBB) disruption, are explored. The mechanisms by which excessive methionine consumption and hyperhomocysteinemia might drive cerebromicrovascular and brain aging processes are elucidated. By presenting an intricate understanding of the relationships among methionine-rich diets, hyperhomocysteinemia, cerebrovascular and brain aging, and cognitive impairment, avenues for future research and potential therapeutic interventions are suggested.

Aging-Related Accumulation of Truncated Oxidized Phospholipids Augments Infectious Lung Injury and Endothelial Dysfunction via Cluster of Differentiation 36-Dependent Mechanism

Truncated phospholipid oxidation products (Tr-OxPL) increase in blood circulation with aging; however, their role in the severity of vascular dysfunction and bacterial lung injury in aging groups remains poorly understood. We investigated the effects of six Tr-OxPL species: KOdiA-PC, POVPC, PONPC, PGPC, Paz-PC, and Lyso-PC on endothelial dysfunction and lung inflammation caused by heat-killed Staphylococcus aureus (HKSA) in young (aged 2-4 months) and old (aged 12-18 months) mice, organotypic culture of precisely cut lung slices, and endothelial cells (mLEC) isolated from young and old mice. HKSA and Tr-OxPL combination caused a higher degree of vascular leak, the accumulation of inflammatory cells and protein in bronchoalveolar lavage, and inflammatory gene expression in old mice lungs. HKSA caused a greater magnitude of inflammatory gene activation in cell and ex vivo cultures from old mice, which was further augmented by Tr-OxPLs. L37pA peptide targeting CD36 receptor attenuated Tr-OxPL-induced endothelial cell permeability in young and old mLEC and ameliorated KOdiA-PC-induced vascular leak and lung inflammation in vivo. Finally, CD36 knockout mice showed better resistance to KOdiA-PC-induced lung injury in both age groups. These results demonstrate the aging-dependent vulnerability of pulmonary vasculature to elevated Tr-OxPL, which exacerbates bacterial lung injury. CD36 inhibition is a promising therapeutic approach for improving pneumonia outcomes in aging population.

An integrative review of nonobvious puzzles of cellular and molecular cardiooncology

Oncologic patients are subjected to four major treatment types: surgery, radiotherapy, chemotherapy, and immunotherapy. All nonsurgical forms of cancer management are known to potentially violate the structural and functional integrity of the cardiovascular system. The prevalence and severity of cardiotoxicity and vascular abnormalities led to the emergence of a clinical subdiscipline, called cardiooncology. This relatively new, but rapidly expanding area of knowledge, primarily focuses on clinical observations linking the adverse effects of cancer therapy with deteriorated quality of life of cancer survivors and their increased morbidity and mortality. Cellular and molecular determinants of these relations are far less understood, mainly because of several unsolved paths and contradicting findings in the literature. In this article, we provide a comprehensive view of the cellular and molecular etiology of cardiooncology. We pay particular attention to various intracellular processes that arise in cardiomyocytes, vascular endothelial cells, and smooth muscle cells treated in experimentally-controlled conditions in vitro and in vivo with ionizing radiation and drugs representing diverse modes of anti-cancer activity.

Emerging Roles of Endothelial Nitric Oxide in Preservation of Cognitive Health

eNOS (endothelial nitric oxide synthase) is critically important enzyme responsible for regulation of cardiovascular homeostasis. Under physiological conditions, constitutive eNOS activity and production of endothelial nitric oxide (NO) exert essential neurovascular protective functions. In this review, we first discuss the roles of endothelial NO in prevention of neuronal amyloid accumulation and formation of neurofibrillary tangles, hallmarks of Alzheimer disease pathology. Next, we review existing evidence suggesting that NO released from endothelium prevents activation of microglia, stimulates glycolysis in astrocytes, and increases biogenesis of mitochondria. We also address major risk factors for cognitive impairment including aging and ApoE4 (apolipoprotein 4) genotype with focus on their detrimental effects on eNOS/NO signaling. Relevant to this review, recent studies suggested that aged eNOS heterozygous mice are unique model of spontaneous cerebral small vessel disease. In this regard, we review contribution of dysfunctional eNOS to deposition of Aβ (amyloid-β) into blood vessel wall leading to development of cerebral amyloid angiopathy. We conclude that endothelial dysfunction manifested by the loss of neurovascular protective functions of NO may significantly contribute to development of cognitive impairment.

Endothelial senescence in vascular diseases: current understanding and future opportunities in senotherapeutics

Senescence compromises the essential role that the endothelium plays in maintaining vascular homeostasis, so promoting endothelial dysfunction and the development of age-related vascular diseases. Their biological and clinical significance calls for strategies for identifying and therapeutically targeting senescent endothelial cells. While senescence and endothelial dysfunction have been studied extensively, distinguishing what is distinctly endothelial senescence remains a barrier to overcome for an effective approach to addressing it. Here, we review the mechanisms underlying endothelial senescence and the evidence for its clinical importance. Furthermore, we discuss the current state and the limitations in the approaches for the detection and therapeutic intervention of target cells, suggesting potential directions for future research.

Exogenous Hydrogen Sulfide Activates PI3K/Akt/eNOS Pathway to Improve Replicative Senescence in Human Umbilical Vein Endothelial Cells

Background

Endothelial cell senescence is one of the key mechanistic factors in the pathogenesis of atherosclerosis. In terms of molecules, the phosphatidylinositol 3-kinase/protein kinase B/endothelial nitric oxide synthase (PI3K/Akt/eNOS) signaling plays an important role in the prevention and control of endothelial cell senescence, while hydrogen sulfide (H2S) improves the induced precocious senescence of endothelial cells through the PI3K/Akt/eNOS pathway. Comparatively, replicative senescence in endothelial cells is more in line with the actual physiological changes of human aging. This study aims to investigate the mechanism by which H2S improves endothelial cell replicative senescence and the involvement of the PI3K/Akt/eNOS pathway.

Methods

we established a model of replicative senescence in human umbilical vein endothelial cells (HUVECs) and explored the effect of 200 μmol/L sodium hydrosulfide (NaHS; a donor of H2S) on senescence, which was determined by cell morphology, the expression level of plasminogen activator inhibitor 1 (PAI-1), and the positive rate of senescence-associated β-galactosidase (SA-β-Gal) staining. Cell viability was detected by MTT assay to evaluate the effect of NaHS and the PI3K inhibitor, LY294002. Meanwhile, the protein expression of PI3K, Akt, p-Akt, and eNOS in endothelial cells of each group was detected by Western blot.

Results

the replicative senescence model was established in HUVECs at the passage of 16 cumulative cell population doubling values (CPDL). Treatment with NaHS not only significantly reduced the expression of PAI-1 and the positive rate of SA-β-Gal in HUVEC's replicative senescence model but also notably increased the expression of PI3K, p-Akt, p-eNOS, and the content of nitric oxide(NO). However, the effects of NaHS on the expression of the pathway and the content of NO in HUVECs were abolished when LY294002 specifically inhibited PI3K.

Conclusion

NaHS improves the replicative senescence of HUVECs with the contribution of the PI3K/Akt/eNOS pathway.

Vascular dysfunction in COVID-19 patients: update on SARS-CoV-2 infection of endothelial cells and the role of long non-coding RNAs

Although COVID-19 is primarily a respiratory disease, it may affect also the cardiovascular system. COVID-19 patients with cardiovascular disorder (CVD) develop a more severe disease course with a significantly higher mortality rate than non-CVD patients. A common denominator of CVD is the dysfunction of endothelial cells (ECs), increased vascular permeability, endothelial-to-mesenchymal transition, coagulation, and inflammation. It has been assumed that clinical complications in COVID-19 patients suffering from CVD are caused by SARS-CoV-2 infection of ECs through the angiotensin-converting enzyme 2 (ACE2) receptor and the cellular transmembrane protease serine 2 (TMPRSS2) and the consequent dysfunction of the infected vascular cells. Meanwhile, other factors associated with SARS-CoV-2 entry into the host cells have been described, including disintegrin and metalloproteinase domain-containing protein 17 (ADAM17), the C-type lectin CD209L or heparan sulfate proteoglycans (HSPG). Here, we discuss the current data about the putative entry of SARS-CoV-2 into endothelial and smooth muscle cells. Furthermore, we highlight the potential role of long non-coding RNAs (lncRNAs) affecting vascular permeability in CVD, a process that might exacerbate disease in COVID-19 patients.

Regulatory Role of Apoptotic and Inflammasome Related Proteins and Their Possible Functional Aspect in Thiram Associated Tibial Dyschondroplasia of Poultry

Tibial dyschondroplasia debilities apoptotic and inflammasomal conditions that can further destroy chondrocytes. Inflammasomes are specialized protein complexes that process pro-inflammatory cytokines, e.g., interleukin-1β (IL-1β) and IL-18. Moreover, there is mounting evidence that many of the signaling molecules that govern programmed cell death also affect inflammasome activation in a cell-intrinsic way. During the last decade, apoptotic functions have been described for signaling molecules involving inflammatory responses and cell death pathways. Considering these exceptional developments in the knowledge of processes, this review gives a glimpse of the significance of these two pathways and their connected proteins in tibial dyschondroplasia. The current review deeply elaborates on the elevated level of signaling mediators of mitochondrial-mediated apoptosis and the inflammasome. Although investigating these pathways’ mechanisms has made significant progress, this review identifies areas where more study is especially required. It might lead to developing innovative therapeutics for tibial dyschondroplasia and other associated bone disorders, e.g., osteoporosis and osteoarthritis, where apoptosis and inflammasome are the significant pathways.

Endothelial Progenitor Cells as Biomarkers of Cardiovascular Pathologies: A Narrative Review

Endothelial progenitor cells (EPC) may influence the integrity and stability of the vascular endothelium. The association of an altered total EPC number and function with cardiovascular diseases (CVD) and risk factors (CVF) was discussed; however, their role and applicability as biomarkers for clinical purposes have not yet been defined. Endothelial dysfunction is one of the key mechanisms in CVD. The assessment of endothelial dysfunction in vivo remains a major challenge, especially for a clinical evaluation of the need for therapeutic interventions or for primary prevention of CVD. One of the main challenges is the heterogeneity of this particular cell population. Endothelial cells (EC) can become senescent, and the majority of circulating endothelial cells (CEC) show evidence of apoptosis or necrosis. There are a few viable CECs that have properties similar to those of an endothelial progenitor cell. To use EPC levels as a biomarker for vascular function and cumulative cardiovascular risk, a correct definition of their phenotype, as well as an update on the clinical application and practicability of current isolation methods, are an urgent priority.

Endothelial Piezo1 sustains muscle capillary density and contributes to physical activity

Piezo1 forms mechanically activated nonselective cation channels that contribute to endothelial response to fluid flow. Here we reveal an important role in the control of capillary density. Conditional endothelial cell-specific deletion of Piezo1 in adult mice depressed physical performance. Muscle microvascular endothelial cell apoptosis and capillary rarefaction were evident and sufficient to account for the effect on performance. There was selective upregulation of thrombospondin-2 (TSP2), an inducer of endothelial cell apoptosis, with no effect on TSP1, a related important player in muscle physiology. TSP2 was poorly expressed in muscle endothelial cells but robustly expressed in muscle pericytes, in which nitric oxide (NO) repressed the Tsp2 gene without an effect on Tsp1. In endothelial cells, Piezo1 was required for normal expression of endothelial NO synthase. The data suggest an endothelial cell-pericyte partnership of muscle in which endothelial Piezo1 senses blood flow to sustain capillary density and thereby maintain physical capability.

Cardiovascular ramifications of therapy-induced endothelial cell senescence in cancer survivors

Cancer survivorship has remarkably improved over the past decades; nevertheless, cancer survivors are burdened with multiple health complications primarily caused by their cancer therapy. Therapy-induced senescence is recognized as a fundamental mechanism contributing to adverse health complications in cancer survivors. In this mini-review, we will discuss the recent literature describing the mechanisms of cancer therapy-induced senescence. We will focus on endothelial cell senescence since it has been shown to be a key player in numerous cardiovascular complications. We will also discuss novel senotherapeutic approaches that have the potential to combat therapy-induced endothelial cell senescence.

Incidence and predictors of progression of carotid atherosclerosis in a low-income Chinese population-a prospective cohort study

OBJECTIVE

More than 200 million individuals have been diagnosed with carotid atherosclerosis (CAS) in China. We aimed to investigate the incidence and potential predictors of CAS progression in a low-income rural area in China.

METHODS

A population-based cohort study was conducted on individuals aged ≥45 years from 2014 to 2019. Multivariable analyses were used to investigate the predictors of carotid plaque (CP) formation, plaque number, and carotid intima-media thickness (CIMT).

RESULTS

A total of 1479 participants were finally enrolled in this study. The incidence rate of CP was 42.9 cases per 1000 person-years, and the progression of median CIMT was 137.50 μm over five years. The risk of CP formation increased 2-fold in participants aged ≥75 years (P = 0.002) compared with those aged 45-54 years. The corresponding risk was 59% higher in participants with hypertension (P = 0.001) and 73% higher in alcohol drinkers (P = 0.006). With each 1- standard deviations (SD) increase in high- and low-density lipoprotein cholesterol levels, the risk of CP occurrence decreased by 16% (P = 0.016) and increased by 29% (P = 0.002), respectively. Participants aged ≥75 years exhibited a 3.3-fold higher risk of having a high number of plaques than those aged 45-54 years (P = 0.014). Moreover, older age and the waist-to-hip ratio were independent predictors of CIMT progression.

CONCLUSIONS

This is the first longitudinal study to explore the incidence and predictors of CAS progression in a low-income rural population in China with a high prevalence of stroke. More detailed and precise strategies for prevention and intervention of CAS progression are necessary, especially in low-income rural areas in China.

An Overview of NO Signaling Pathways in Aging

Nitric Oxide (NO) is a potent signaling molecule involved in the regulation of various cellular mechanisms and pathways under normal and pathological conditions. NO production, its effects, and its efficacy, are extremely sensitive to aging-related changes in the cells. Herein, we review the mechanisms of NO signaling in the cardiovascular system, central nervous system (CNS), reproduction system, as well as its effects on skin, kidneys, thyroid, muscles, and on the immune system during aging. The aging-related decline in NO levels and bioavailability is also discussed in this review. The decreased NO production by endothelial nitric oxide synthase (eNOS) was revealed in the aged cardiovascular system. In the CNS, the decline of the neuronal (n)NOS production of NO was related to the impairment of memory, sleep, and cognition. NO played an important role in the aging of oocytes and aged-induced erectile dysfunction. Aging downregulated NO signaling pathways in endothelial cells resulting in skin, kidney, thyroid, and muscle disorders. Putative therapeutic agents (natural/synthetic) affecting NO signaling mechanisms in the aging process are discussed in the present study. In summary, all of the studies reviewed demonstrate that NO plays a crucial role in the cellular aging processes.

Cellular senescence promotes endothelial activation through epigenetic alteration, and consequently accelerates atherosclerosis

Senescent vascular cells are detected in atherosclerotic lesion, and its involvement in the development of atherosclerosis has been revealed; however, whether and the mechanism by which endothelial cell (EC) senescence is causally implicated in atherosclerosis remains unclear. We here investigate a role of EC senescence in atherosclerosis by utilizing EC-specific progeroid mice that overexpress the dominant negative form of telomeric repeat-binding factor 2 under the control of the Tie2 or vascular endothelial cadherin promoter. EC-specific progeria accelerated atherosclerosis in mice with target deletion of ApoE. Mechanistically, senescent ECs were markedly sensitive for inflammation-mediated VCAM-1 induction, leading to enhanced monocyte adhesion. Inhibition of NF-κB signaling abolished the enhanced inflammatory responses in senescent ECs, while NF-κB nuclear translocation in response to TNF-α were similar between young and senescent ECs. We found a higher association of VCAM-1 gene with active histone H3 trimethylated on lysine 4, leading to increased NF-κB accessibility in senescent ECs. Our data revealed that EC cellular senescence causes endothelial hyper-inflammability through epigenetic alteration, which consequently accelerates atherosclerosis. Therefore, EC senescence is a promising therapeutic target for the prevention and/or treatment of atherosclerotic disease in elderly population.

Evolving structure-function relations during aortic maturation and aging revealed by multiphoton microscopy

The evolving microstructure and mechanical properties that promote homeostasis in the aorta are fundamental to age-specific adaptations and disease progression. We combine ex vivo multiphoton microscopy and biaxial biomechanical phenotyping to quantify and correlate layer-specific microstructural parameters, for the primary extracellular matrix components (fibrillar collagen and elastic lamellae) and cells (endothelial, smooth muscle, and adventitial), with mechanical properties of the mouse aorta from weaning through natural aging up to one year. The aging endothelium was characterized by progressive reductions in cell density and altered cellular orientation. The media similarly showed a progressive decrease in smooth muscle cell density and alignment though with inter-lamellar widening from intermediate to older ages, suggesting cell hypertrophy, matrix accumulation, or both. Despite not changing in tissue thickness, the aging adventitia exhibited a marked thickening and straightening of collagen fiber bundles and reduction in cell density, suggestive of age-related remodeling not growth. Multiple microstructural changes correlated with age-related increases in circumferential and axial material stiffness, among other mechanical metrics. Because of the importance of aging as a risk factor for cardiovascular diseases, understanding the normal progression of structural and functional changes is essential when evaluating superimposed disease-related changes as a function of the age of onset.

The Aging Vasculature: Glucose Tolerance, Hypoglycemia and the Role of the Serum Response Factor

The fastest growing demographic in the U.S. at the present time is those aged 65 years and older. Accompanying advancing age are a myriad of physiological changes in which reserve capacity is diminished and homeostatic control attenuates. One facet of homeostatic control lost with advancing age is glucose tolerance. Nowhere is this more accentuated than in the high proportion of older Americans who are diabetic. Coupled with advancing age, diabetes predisposes affected subjects to the onset and progression of cardiovascular disease (CVD). In the treatment of type 2 diabetes, hypoglycemic episodes are a frequent clinical manifestation, which often result in more severe pathological outcomes compared to those observed in cases of insulin resistance, including premature appearance of biomarkers of senescence. Unfortunately, molecular mechanisms of hypoglycemia remain unclear and the subject of much debate. In this review, the molecular basis of the aging vasculature (endothelium) and how glycemic flux drives the appearance of cardiovascular lesions and injury are discussed. Further, we review the potential role of the serum response factor (SRF) in driving glycemic flux-related cellular signaling through its association with various proteins.

Molecular mechanisms and cardiovascular implications of cancer therapy-induced senescence

Cancer treatment has been associated with accelerated aging that can lead to early-onset health complications typically experienced by older populations. In particular, cancer survivors have an increased risk of developing premature cardiovascular complications. In the last two decades, cellular senescence has been proposed as an important mechanism of premature cardiovascular diseases. Cancer treatments, specifically anthracyclines and radiation, have been shown to induce senescence in different types of cardiovascular cells. Additionally, clinical studies identified increased systemic markers of senescence in cancer survivors. Preclinical research has demonstrated the potential of several approaches to mitigate cancer therapy-induced senescence. However, strategies to prevent and/or treat therapy-induced cardiovascular senescence have not yet been translated to the clinic. In this review, we will discuss how therapy-induced senescence can contribute to cardiovascular complications. Thereafter, we will summarize the current in vitro, in vivo, and clinical evidence regarding cancer therapy-induced cardiovascular senescence. Then, we will discuss interventional strategies that have the potential to protect against therapy-induced cardiovascular senescence. To conclude, we will highlight challenges and future research directions to mitigate therapy-induced cardiovascular senescence in cancer survivors.

Myofibroblast-Derived Exosome Induce Cardiac Endothelial Cell Dysfunction

Background: Endothelial cells (ECs) play a critical role in the maintenance of vascular homeostasis and in heart function. It was shown that activated fibroblast-derived exosomes impair cardiomyocyte function in hypertrophic heart, but their effect on ECs is not yet clear. Thus, we hypothesized that activated cardiac fibroblast-derived exosomes (FB-Exo) mediate EC dysfunction, and therefore modulation of FB-exosomal contents may improve endothelial function. Methods and Results: Exosomes were isolated from cardiac fibroblast (FB)-conditioned media and characterized by nanoparticle tracking analysis and electron microscopy. ECs were isolated from mouse heart. ECs were treated with exosomes isolated from FB-conditioned media, following FB culture with TGF-β1 (TGF-β1-FB-Exo) or PBS (control) treatment. TGF-β1 significantly activated fibroblasts as shown by increase in collagen type1 α1 (COL1α1), periostin (POSTN), and fibronectin (FN1) gene expression and increase in Smad2/3 and p38 phosphorylation. Impaired endothelial cell function (as characterized by a decrease in tube formation and cell migration along with reduced VEGF-A, Hif1α, CD31, and angiopoietin1 gene expression) was observed in TGF-β1-FB-Exo treated cells. Furthermore, TGF-β1-FB-Exo treated ECs showed reduced cell proliferation and increased apoptosis as compared to control cells. TGF-β1-FB-Exo cargo analysis revealed an alteration in fibrosis-associated miRNAs, including a significant increase in miR-200a-3p level. Interestingly, miR-200a-3p inhibition in activated FBs, alleviated TGF-β1-FB-Exo-mediated endothelial dysfunction. Conclusions: Taken together, this study demonstrates an important role of miR-200a-3p enriched within activated fibroblast-derived exosomes on endothelial cell biology and function.

Extra-Nuclear Functions of the Transcription Factor Grainyhead-Like 3 in the Endothelium-Interaction with Endothelial Nitric Oxide Synthase

We previously demonstrated that the transcription factor Grainyhead-like 3 (GRHL3) has essential functions in endothelial cells by inhibiting apoptosis and promoting migration as well as activation of endothelial nitric oxide synthase (eNOS). We now show that a large portion of the protein is localized to myo-endothelial projections of murine arteries suggesting extra-nuclear functions. Therefore, we generated various deletion mutants to identify the nuclear localization signal (NLS) of GRHL3 and assessed potential extra-nuclear functions. Several large-scale deletion mutants were incapable of activating a GRHL3-dependent reporter construct, which could either be due to deficiencies in transcriptional activation or to impaired nuclear import. One of these mutants encompassed a predicted bipartite NLS whose deletion led to the retention of GRHL3 outside the nucleus. Interestingly, this mutant retained functions of the full-length protein as it could still inhibit pathways inducing endothelial cell apoptosis. As apoptosis protection by GRHL3 depends on NO-production, we examined whether GRHL3 could interact with eNOS and showed a direct interaction, which was enhanced with the extra-nuclear GRHL3 variant. The observation that endogenous GRHL3 also interacts with eNOS in intact murine arteries corroborated these findings and substantiated the notion that GRHL3 has important extra-nuclear functions in the endothelium.

Exosomes and Exosomal MicroRNAs in Age-Associated Stroke

Aging has been considered to be the most important non-modifiable risk factor for stroke and death. Changes in circulation factors in the systemic environment, cellular senescence and artery hypertension during human ageing have been investigated. Exosomes are nanosize membrane vesicles that can regulate target cell functions via delivering their carried bioactive molecules (e.g. protein, mRNA, and microRNAs). In the central nervous system, exosomes and exosomal microRNAs play a critical role in regulating neurovascular function, and are implicated in the initiation and progression of stroke. MicroRNAs are small non-coding RNAs that have been reported to play critical roles in various biological processes. Recently, evidence has shown that microRNAs are packaged into exosomes and can be secreted into the systemic and tissue environment. Circulating microRNAs participate in cellular senescence and contribute to age-associated stroke. Here, we provide an overview of current knowledge on exosomes and their carried microRNAs in the regulation of cellular and organismal ageing processes, demonstrating the potential role of exosomes and their carried microRNAs in age-associated stroke.

Obesity-induced cognitive impairment in older adults: a microvascular perspective

Over two-thirds of individuals aged 65 and older are obese or overweight in the United States. Epidemiological data show an association between the degree of adiposity and cognitive dysfunction in the elderly. In this review, the pathophysiological roles of microvascular mechanisms, including impaired endothelial function and neurovascular coupling responses, microvascular rarefaction, and blood-brain barrier disruption in the genesis of cognitive impairment in geriatric obesity are considered. The potential contribution of adipose-derived factors and fundamental cellular and molecular mechanisms of senescence to exacerbated obesity-induced cerebromicrovascular impairment and cognitive decline in aging are discussed.

SARS-CoV-2 Mediated Endothelial Dysfunction: The Potential Role of Chronic Oxidative Stress

Endothelial cells have emerged as key players in SARS-CoV-2 infection and COVID-19 inflammatory pathologies. Dysfunctional endothelial cells can promote chronic inflammation and disease processes like thrombosis, atherosclerosis, and lung injury. In endothelial cells, mitochondria regulate these inflammatory pathways via redox signaling, which is primarily achieved through mitochondrial reactive oxygen species (mtROS). Excess mtROS causes oxidative stress that can initiate and exacerbate senescence, a state that promotes inflammation and chronic endothelial dysfunction. Oxidative stress can also activate feedback loops that perpetuate mitochondrial dysfunction, mtROS overproduction, and inflammation. In this review, we provide an overview of phenotypes mediated by mtROS in endothelial cells - such as mitochondrial dysfunction, inflammation, and senescence - as well as how these chronic states may be initiated by SARS-CoV-2 infection of endothelial cells. We also propose that SARS-CoV-2 activates mtROS-mediated feedback loops that cause long-term changes in host redox status and endothelial function, promoting cardiovascular disease and lung injury after recovery from COVID-19. Finally, we discuss the implications of these proposed pathways on long-term vascular health and potential treatments to address these chronic conditions.

Single-Cell Transcriptional Profiling Reveals Sex and Age Diversity of Gene Expression in Mouse Endothelial Cells

Although it is well-known that sex and age are important factors regulating endothelial cell (EC) function, the impact of sex and age on the gene expression of ECs has not been systematically analyzed at the single cell level. In this study, we performed an integrated characterization of the EC transcriptome of five major organs (e.g., fat, heart-aorta, lung, limb muscle, and kidney) isolated from male and female C57BL/6 mice at 3 and 18 months of age. A total of 590 and 252 differentially expressed genes (DEGS) were identified between females and males in the 3- and 18-month subgroups, respectively. Within the younger and older group, there were 177 vs. 178 DEGS in fat, 305 vs. 469 DEGS in heart/aorta, 22 vs. 37 DEGS in kidney, 26 vs. 439 DEGS in limb muscle, and 880 vs. 274 DEGS in lung. Interestingly, LARS2, a mitochondrial leucyl tRNA synthase, involved in the translation of mitochondrially encoded genes was differentially expressed in all organs in males compared to females in the 3-month group while S100a8 and S100a9, which are calcium binding proteins that are increased in inflammatory and autoimmune states, were upregulated in all organs in males at 18 months. Importantly, findings from RNAseq were confirmed by qPCR and Western blot. Gene enrichment analysis found genes enriched in protein targeting, catabolism, mitochondrial electron transport, IL 1- and IL 2- signaling, and Wnt signaling in males vs. angiogenesis and chemotaxis in females at 3 months. In contrast, ECs from males and females at 18-months had up-regulation in similar pathways involved in inflammation and apoptosis. Taken together, our findings suggest that gene expression is largely similar between males and females in both age groups. Compared to younger mice, however, older mice have increased expression of genes involved in inflammation in endothelial cells, which may contribute to the development of chronic, non-communicable diseases like atherosclerosis, hypertension, and Alzheimer's disease with age.

Apoptosis resistance of senescent cells is an intrinsic barrier for senolysis induced by cardiac glycosides

Targeted elimination of senescent cells, senolysis, is one of the core trends in the anti-aging therapy. Cardiac glycosides were recently proved to be a broad-spectrum senolytics. Here we tested senolytic properties of cardiac glycosides towards human mesenchymal stem cells (hMSCs). Cardiac glycosides had no senolytic ability towards senescent hMSCs of various origins. Using biological and bioinformatic approaches we compared senescence development in 'cardiac glycosides-sensitive' A549 and '-insensitive' hMSCs. The absence of senolysis was found to be mediated by the effective potassium import and increased apoptosis resistance in senescent hMSCs. Weakening "antiapoptotic defense" predisposes hMSCs to senolysis. We revealed that apoptosis resistance, previously recognized as a common characteristic of senescence, in fact, is not a general feature of senescent cells. Moreover, only apoptosis-prone senescent cells are sensitive to cardiac glycosides-induced senolysis. Thus, we can speculate that the effectiveness of senolysis might depend on whether senescent cells indeed become apoptosis-resistant as compared to their proliferating counterparts.

A review of myocardial ischaemia/reperfusion injury: Pathophysiology, experimental models, biomarkers, genetics and pharmacological treatment

Cardiovascular diseases are known to be the most fatal diseases worldwide. Ischaemia/reperfusion (I/R) injury is at the centre of the pathology of the most common cardiovascular diseases. According to the World Health Organization estimates, ischaemic heart disease is the leading global cause of death, causing more than 9 million deaths in 2016. After cardiovascular events, thrombolysis, percutaneous transluminal coronary angioplasty or coronary bypass surgery are applied as treatment. However, after restoring coronary blood flow, myocardial I/R injury may occur. It is known that this damage occurs due to many pathophysiological mechanisms, especially increasing reactive oxygen types. Besides causing cardiomyocyte death through multiple mechanisms, it may be an important reason for affecting other cell types such as platelets, fibroblasts, endothelial and smooth muscle cells and immune cells. Also, polymorphonuclear leukocytes are associated with myocardial I/R damage during reperfusion. This damage may be insufficient in patients with co-morbidity, as it is demonstrated that it can be prevented by various endogenous antioxidant systems. In this context, the resulting data suggest that optimal cardioprotection may require a combination of additional or synergistic multi-target treatments. In this review, we discussed the pathophysiology, experimental models, biomarkers, treatment and its relationship with genetics in myocardial I/R injury. SIGNIFICANCE OF THE STUDY: This review summarized current information on myocardial ischaemia/reperfusion injury (pathophysiology, experimental models, biomarkers, genetics and pharmacological therapy) for researchers and reveals guiding data for researchers, especially in the field of cardiovascular system and pharmacology.

Bioactivity of Circulatory Factors After Pulmonary Exposure to Mild or Stainless Steel Welding Fumes

Studies suggest that alterations in circulating factors are a driver of pulmonary-induced cardiovascular dysfunction. To evaluate, if circulating factors effect endothelial function after a pulmonary exposure to welding fumes, an exposure known to induce cardiovascular dysfunction, serum collected from Sprague Dawley rats 24 h after an intratracheal instillation exposure to 2 mg/rat of 2 compositionally distinct metal-rich welding fume particulates (manual metal arc welding using stainless steel electrodes [MMA-SS] or gas metal arc welding using mild steel electrodes [GMA-MS]) or saline was used to test molecular and functional effects of in vitro cultures of primary cardiac microvascular endothelial cells (PCMEs) or ex vivo organ cultures. The welding fumes elicited significant pulmonary injury and inflammation with only minor changes in measured serum antioxidant and cytokine levels. PCME cells were challenged for 4 h with serum collected from exposed rats, and 84 genes related to endothelial function were analyzed. Changes in relative mRNA patterns indicated that serum from rats exposed to MMA-SS, and not GMA-MS or PBS, could influence several functional aspects related to endothelial cells, including cell migration, angiogenesis, inflammation, and vascular function. The predictions were confirmed using a functional in vitro assay (scratch assay) as well as an ex vivo multicellular environment (aortic ring angiogenesis assay), validating the concept that endothelial cells can be used as an effective screening tool of exposed workers for determining bioactivity of altered circulatory factors. Overall, the results indicate that pulmonary MMA-SS fume exposure can cause altered endothelial function systemically via altered circulating factors.

β-catenin promotes endothelial survival by regulating eNOS activity and flow-dependent anti-apoptotic gene expression

Increased endothelial cell (EC) apoptosis is associated with the development of atherosclerotic plaques that develop predominantly at sites exposed to disturbed flow (DF). Strategies to promote EC survival may therefore represent a novel therapeutic approach in cardiovascular disease. Nitric oxide (NO) and β-catenin have both been shown to promote cell survival and they interact in ECs as we previously demonstrated. Here we investigated the physiological role of β-catenin as a mediator of NO-induced cell survival in ECs. We found that β-catenin depleted human umbilical vein ECs (HUVEC) stimulated with pharmacological activators of endothelial NO synthase (eNOS) showed a reduction in eNOS phosphorylation (Ser1177) as well as reduced intracellular cyclic guanosine monophosphate levels compared to control cells in static cultures. In addition, β-catenin depletion abrogated the protective effects of the NO donor, S-nitroso-N-acetylpenicillamine, during TNFα- and H₂O₂-induced apoptosis. Using an orbital shaker to generate shear stress, we confirmed eNOS and β-catenin interaction in HUVEC exposed to undisturbed flow and DF and showed that β-catenin depletion reduced eNOS phosphorylation. β-catenin depletion promoted apoptosis exclusively in HUVEC exposed to DF as did inhibition of soluble guanylate cyclase (sGC) or β-catenin transcriptional activity. The expression of the pro-survival genes, Bcl-2 and survivin was also reduced following inhibition of β-catenin transcriptional activity, as was the expression of eNOS. In conclusion, our data demonstrate that β-catenin is a positive regulator of eNOS activity and cell survival in human ECs. sGC activity and β-catenin-dependent transcription of Bcl-2, survivin, BIRC3 and eNOS are essential to maintain cell survival in ECs under DF.

Oxidative Stress and Thrombosis during Aging: The Roles of Oxidative Stress in RBCs in Venous Thrombosis

Mid-life stage adults are at higher risk of developing venous thrombosis (VT)/thromboembolism (VT/E). Aging is characterized by an overproduction of reactive oxygen species (ROS), which could evoke a series of physiological changes involved in thrombosis. Here, we focus on the critical role of ROS within the red blood cell (RBC) in initiating venous thrombosis during aging. Growing evidence has shifted our interest in the role of unjustifiably unvalued RBCs in blood coagulation. RBCs can be a major source of oxidative stress during aging, since RBC redox homeostasis is generally compromised due to the discrepancy between prooxidants and antioxidants. As a result, ROS accumulate within the RBC due to the constant endogenous hemoglobin (Hb) autoxidation and NADPH oxidase activation, and the uptake of extracellular ROS released by other cells in the circulation. The elevated RBC ROS level affects the RBC membrane structure and function, causing loss of membrane integrity, and decreased deformability. These changes impair RBC function in hemostasis and thrombosis, favoring a hypercoagulable state through enhanced RBC aggregation, RBC binding to endothelial cells affecting nitric oxide availability, RBC-induced platelet activation consequently modulating their activity, RBC interaction with and activation of coagulation factors, increased RBC phosphatidylserine exposure and release of microvesicles, accelerated aging and hemolysis. Thus, RBC oxidative stress during aging typifies an ultimate mechanism in system failure, which can affect major processes involved in the development of venous thrombosis in a variety of ways. The reevaluated concept of the critical role of RBC ROS in the activation of thrombotic events during aging will help identify potential targets for novel strategies to prevent/reduce the risk for VT/E or VT/E recurrences in mid-life stage adults.

Implications of liver donor age on ischemia reperfusion injury and clinical outcomes

The aging process causes detrimental changes in a variety of organ systems. These changes include: lesser ability to cope with stress, impaired repair mechanisms and decreased cellular functional reserve capacity. Not surprisingly, aging has been associated with increased susceptibility of donor heart and kidneys grafts to ischemia reperfusion injury (IRI). In the context of liver transplantation, however, the effect of donor age seems to be less influential in predisposing the graft to IRI. In fact, a widely comprehensive understanding of IRI in the aged liver has yet to be agreed upon in the literature. Nevertheless, there have been many reported implications of increased liver donor age with poor clinical outcomes besides IRI. These other poor outcomes include: earlier HCV recurrence, increased rates of acute rejection and greater resistance to tolerance induction. While these other correlations have been identified, it is important to re-emphasize the fact that a unified consensus in regard to liver donor age and IRI has not yet been reached among researchers in this field. Many researchers have even demonstrated that the extent of IRI in aged livers can be ameliorated by careful donor selection, strict allocation or novel therapeutic modalities to decrease IRI. Thus, the goals of this review paper are twofold: 1) To delineate and summarize the conflicting data in regard to liver donor age and IRI. 2) Suggest that careful donor selection, appropriate allocation and strategic effort to minimize IRI can reduce the frequency of a variety of poor outcomes with aged liver donations.

Isolation and characterization of endothelial progenitor cells from canine bone marrow

Endothelial progenitor cells (EPC) are located predominantly in the bone marrow. These cells are useful for treating human vascular diseases; they also are a possible target for restricting blood vessel growth for tumors. Little is known about canine EPC. We investigated a bone marrow EPC isolation method that combines the whole bone marrow culture method and the differential adherent speed method using stillborn canines. MTT proliferation, flow cytometry detection, Dil-ac-LDL uptake, FITC-UEA-1 binding and matrigel assays were used to identify and characterize EPC. We isolated two types of EPC: early EPC and late EPC. We found that isolated cells produced typical colony and cobblestone morphology, and were positive for CD31, CD34, CD133 and VEGFR-2. Significant differences were observed in the intensity of expression between early and late EPC, which suggests their different roles during angiogenesis and vasculogenesis. Both early and late EPC were positive for Dil-ac-LDL and FITC-UEA-1, and displayed tube formation when re-suspended in matrigel, both of which are important functional criteria for identifying EPC. Our method is a novel, effective and efficient way to produce enriched EPC.

The roles of MTOR and miRNAs in endothelial cell senescence

Accumulation of senescent cells in vascular endothelium is known to contribute to vascular aging and increases the risk of developing cardiovascular diseases. The involvement of classical pathways such as p53/p21 and p16/pRB in cellular senescence are well described but there are emerging evidence supporting the increasingly important role of mammalian target of rapamycin (MTOR) as driver of cellular senescence via these pathways or other effector molecules. MicroRNAs (miRNAs) are a highly conserved group of small non-coding RNAs (18-25 nucleotides), instrumental in modulating the expression of target genes associated with various biological and cellular processes including cellular senescence. The inhibition of MTOR activity is predominantly linked to cellular senescence blunting and prolonged lifespan in model organisms. To date, known miRNAs regulating MTOR in endothelial cell senescence remain limited. Herein, this review discusses the roles of MTOR and MTOR-associated miRNAs in regulating endothelial cell senescence, including the crosstalk between MTOR Complex 1 (MTORC1) and cell cycle pathways and the emerging role of MTORC2 in cellular senescence. New insights on how MTOR and miRNAs coordinate underlying molecular mechanisms of endothelial senescence will provide deeper understanding and clarity to the complexity of the regulation of cellular senescence.

Hydrogen Sulfide Protects Against High Glucose-Induced Human Umbilical Vein Endothelial Cell Injury Through Activating PI3K/Akt/eNOS Pathway

Purpose

Dysfunction of endothelial cells plays a key role in the pathogenesis of diabetic atherosclerosis. High glucose (HG) has been found as a key factor in the progression of diabetic complications, including atherosclerosis. PI3K/Akt/eNOS signaling pathway has been shown to involve in HG-induced vascular injuries. Hydrogen sulfide (H₂S) has been found to exhibit protective effects on HG-induced vascular injuries. Moreover, H₂S activates PI3K/Akt/eNOS pathway in endothelial cells. Thus, the present study aimed to determine if H₂S exerts protective effects against HG-induced injuries of human umbilical vein endothelial cells (HUVECs) via activating PI3K/Akt/eNOS signaling.

Materials and Methods

The endothelial protective effects of H₂S were evaluated and compared to the controlled groups. Cell viability, cell migration and tube formation were determined by in vitro functional assays; protein levels were evaluated by Western blot assay and ELISA; cell apoptosis was determined by Hoechst 33258 nuclear staining; Reactive oxygen species (ROS) production was evaluated by the ROS detection kit.

Results

HG treatment significantly inhibited PI3K/Akt/eNOS signaling in HUVECs, which was partially reversed by the H2S treatment. HG treatment inhibited cell viability of HUVECs, which were markedly prevented by H₂S or PI3K agonist Y-P 740. HG treatment also induced HUVEC cell apoptosis by increasing the protein levels of cleaved caspase 3, Bax and Bcl-2, which were significantly attenuated by H₂S or 740 Y-P. ROS production and gp91^phox protein level were increased by HG treatment in HUVECs and this effect can be blocked by the treatment with H₂S or Y-P 740. Moreover, HG treatment increased the protein levels of pro-inflammatory cytokines, caspase-1 and phosphorylated JNK, which was significantly attenuated by H₂S or Y-P 740. Importantly, the cytoprotective effect of H₂S against HG-induced injury was inhibited by LY294002 (an inhibitor of PI3K/Akt/eNOS signaling pathway).

Conclusion

The present study demonstrated that exogenous H₂S protects endothelial cells against HG-induced injuries by activating PI3K/Akt/eNOS pathway. Based on the above findings, we proposed that reduced endogenous H₂S levels and the subsequent PI3K/Akt/eNOS signaling impairment may be the important pathophysiological mechanism underlying hyperglycemia-induced vascular injuries.

Changes of the coronary arteries and cardiac microvasculature with aging: Implications for translational research and clinical practice

Aging results in functional and structural changes in the cardiovascular system, translating into a progressive increase of mechanical vessel stiffness, due to a combination of changes in micro-RNA expression patterns, autophagy, arterial calcification, smooth muscle cell migration and proliferation. The two pivotal mechanisms of aging-related endothelial dysfunction are oxidative stress and inflammation, even in the absence of clinical disease. A comprehensive understanding of the aging process is emerging as a primary concern in literature, as vascular aging has recently become a target for prevention and treatment of cardiovascular disease. Change of life-style, diet, antioxidant regimens, anti-inflammatory treatments, senolytic drugs counteract the pro-aging pathways or target senescent cells modulating their detrimental effects. Such therapies aim to reduce the ineluctable burden of age and contrast aging-associated cardiovascular dysfunction. This narrative review intends to summarize the macrovascular and microvascular changes related with aging, as a better understanding of the pathways leading to arterial aging may contribute to design new mechanism-based therapeutic approaches to attenuate the features of vascular senescence and its clinical impact on the cardiovascular system.

The Role of Sirtuin1 in Regulating Endothelial Function, Arterial Remodeling and Vascular Aging

Sirtuin1 (SIRT1), which belongs to a highly conserved family of protein deacetylase, is one of the best-studied sirtuins. SIRT1 is involved in a variety of biological processes, including energy metabolism, cell proliferation and survival, chromatin dynamics, and DNA repair. In the vasculature, SIRT1 is ubiquitously expressed in endothelial cells, smooth muscle cells, and perivascular adipose tissues (PVAT). Endothelial SIRT1 plays a unique role in vasoprotection by regulating a large variety of proteins, including endothelial nitric oxide synthase (eNOS). In endothelial cells, SIRT1 and eNOS regulate each other synergistically through positive feedback mechanisms for the maintenance of endothelial function. Recent studies have shown that SIRT1 plays a vital role in modulating PVAT function, arterial remodeling, and vascular aging. In the present article, we summarize recent findings, review the molecular mechanisms and the potential of SIRT1 as a therapeutic target for the treatment of vascular diseases, and discuss future research directions.

Endothelial dysfunction and angiogenesis impairment in the ageing vasculature

Ageing is the main risk factor for the development of cardiovascular diseases. A central mechanism by which ageing promotes vascular pathologies is compromising endothelial health. The age-related attenuation of endothelium-dependent dilator responses (endothelial dysfunction) associated with impairment of angiogenic processes and the subsequent pathological remodelling of the microcirculation contribute to compromised tissue perfusion and exacerbate functional decline in older individuals. This Review focuses on cellular, molecular, and functional changes that occur in the endothelium during ageing. We explore the links between oxidative and nitrative stress and the conserved molecular pathways affecting endothelial dysfunction and impaired angiogenesis during ageing. We also speculate on how these pathological processes could be therapeutically targeted. An improved understanding of endothelial biology in older patients is crucial for all cardiologists because maintenance of a competently functioning endothelium is critical for adequate tissue perfusion and long-term cardiac health.

Age-related changes of the human retinal vessels: Possible involvement of lipid peroxidation

BACKGROUND

Aging of the human retina is accompanied by oxidative stress that exerts profound changes in the retinal neurons. It is unknown if oxidative stress influences the cellular components of the retinal vessels in some ways.

METHODS

We examined changes in retinal vessels in human donor eyes (age: 35-94 years; N=18) by light and transmission electron microscopy, TUNEL and immunohistochemistry for biomarkers of vascular smooth muscle cells (SMC; actin), oxidative stress (4-hydroxy 2-nonenal [HNE] and nitrotyrosine), microglia (Iba-1) and vessels (isolectin B₄).

RESULTS

The earliest changes in the endothelium and pericytes of capillaries are apparent from the seventh decade. With aging, there is clear loss of organelles and cytoplasmic filaments, and a progressive thickening of the endothelial and pericyte basal lamina. Loss of filaments, accumulation of lipofuscin and autophagic vacuoles are significant events in aging pericytes and SMC. Actin immunolabelling reveals discontinuity in arterial SMC layers during eighth decade, indicating partial degeneration of SMC. This is followed by hyalinization, with degeneration of the endothelium and SMC in arteries and arterioles of the nerve fibre layer (NFL) and ganglion cell layer in ninth decade. Iba-1 positive microglia were in close contact with the damaged vessels in inner retina, and their cytoplasm was rich in lysosomes. HNE immunoreactivity, but not of nitrotyrosine, was detected in aged vessels from seventh decade onwards, suggesting that lipid peroxidation is a major problem of aged vessels. However, TUNEL positivity seen during this period was limited to few arteries and venules of NFL.

CONCLUSION

This study shows prominent age-related alterations of the pericytes and SMC of retinal vessels. These changes may limit the energy supply to the neurons and be responsible for age-related loss of neurons of the inner retina.

Age-Related Impairment of Structure and Function of Iliac Artery Endothelium in Rats Is Improved by Elevated Fluid Shear Stress

Background

Aging plays an important role in endothelial dysfunction. Fluid shear stress (FSS) can activate endothelial cells (ECs). Herein, we tested the hypothesis that this endothelial impairment could be improved by elevated FSS (EFSS) in aged rats.

Material/Methods

EFSS was created through ligation of the unilateral common iliac artery in 20-−month-old rats, evaluated by measuring blood flow velocity with Doppler spectrum. The effect of FSS on aged ECs was examined by senescence-associated β-galactosidase (SA-β-Gal) staining, ultrastructural observation, and immunostaining and qPCR analysis of eNOS and SIRT1 expression on both the mRNA and protein levels.

Results

(1) FSS was significantly increased in the right common iliac artery (RCIA) in rats with the ligation of the left common iliac artery (LCIA). (2) SA-β-Gal staining was significantly attenuated by EFSS in the RCIA of aged rats. (3) Ultrastructural observation showed that ECs in the RCIA of normal aged rats became irregular and enlarged, with increasingly polypoid nuclei and fewer mitochondria, whereas ECs in the RCIA of aged rats with LCIA ligation became more prominent and contained more mitochondria. (4) eNOS and SIRT1 expression in the RCIA of aged rats with LCIA ligation was significantly upregulated compared with that in control group rats.

Conclusions

The present study for the first time shows that EFSS has the ability to improve age-related impairment of endothelial structure and functions.

Effects of HIV-1 gp120 and tat on endothelial cell sensescence and senescence-associated microRNAs

The aim of this study was to determine, in vitro, the effects of X4 and R5 HIV‐1 gp120 and Tat on: (1) endothelial cell senescence and (2) endothelial cell microRNA (miR) expression. Endothelial cells were treated with media without and with: R5 gp120 (100 ng/mL), X4 gp120 (100 ng/mL), or Tat (500 ng/mL) for 24 h and stained for senescence‐associated β‐galactosidase (SA‐β‐gal). Cell expression of miR‐34a, miR‐217, and miR‐146a was determined by RT‐PCR. X4 and R5 gp120 and Tat significantly increased (~100%) cellular senescence versus control. X4 gp120 significantly increased cell expression of miR‐34a (1.60 ± 0.04 fold) and miR‐217 (1.52 ± 0.18), but not miR‐146a (1.25 ± 0.32). R5 gp120 significantly increased miR‐34a (1.23 ± 0.07) and decreased miR‐146a (0.56 ± 0.07). Tat significantly increased miR‐34a (1.49 ± 0.16) and decreased miR‐146a (0.55 ± 0.23). R5 and Tat had no effect on miR‐217 (1.05 ± 0.13 and 1.06 ± 0.24; respectively). HIV‐1 gp120 (X4 and R5) and Tat promote endothelial cell senescence and dysregulation of senescence‐associated miRs.

Protective effect of resveratrol on methylglyoxal-induced endothelial dysfunction in aged rats

BACKGROUND

The cardiovascular benefits of resveratrol (RSV) have been well established by previous experimental and clinical studies. The aim of this study was to investigate the effectiveness of RSV administration on the impaired endothelial function induced by methylglyoxal (MGO), and to elucidate the role of endothelial nitric oxide synthase (eNOS) on its protective effect.

METHODS

Aged Wistar rats (80 weeks old, n = 15) were used in this study. The thoracic aorta was isolated and cut into rings for organ culture. Aortic segments of rats were incubated with MGO (420 µM) in the presence or absence of RSV (30 µM) for 4 h (short-term) or 24 h (long-term). Isometric tension studies were performed by an isolated organ bath in response to acetylcholine (ACh, an endothelium-dependent vasodilator) and sodium nitroprusside (SNP, an endothelium-independent vasodilator). Beside, expressions of eNOS and phospho-eNOS (p-eNOS) (Ser 1177) in thoracic aorta rings were evaluated by immunohistochemistry.

RESULTS

Both short-term and long-term MGO incubation significantly inhibited the relaxation response induced by ACh, while the relaxation to SNP was not significantly altered. In addition, eNOS and p-eNOS expressions decreased significantly in arteries incubated with MGO. The impaired endothelial reactivity as well as decreased expressions of eNOS and p-eNOS in MGO-incubated vessels were significantly improved by RSV treatment.

CONCLUSIONS

Endothelium-dependent vasodilatation of the thoracic aorta was significantly inhibited by MGO administration, and RSV may improve vascular endothelial function. The protective effect of RSV against MGO-induced endothelial dysfunction seems to be via increased eNOS expression and activity.

Endothelial progenitor cells attenuate the lung ischemia/reperfusion injury following lung transplantation via the endothelial nitric oxide synthase pathway

OBJECTIVE

Endothelial progenitor cells (EPCs) can improve endothelial integrity. This study aimed to examine the effects and the mechanism of EPCs on lung ischemia-reperfusion injury (LIRI).

METHODS

Wistar rats were randomized into the sham or the left lung transplantation group. The recipients were randomized and treated with vehicle as the LIRI group, with EPC as the EPC group, or with N5-(1-iminoethyl)-l-ornithine-pretreated EPC as the EPC/L group (n = 8 per group). The ratios of arterial oxygen partial pressure to fractional inspiratory oxygen were measured. The lung wet-to-dry weight ratios, protein levels, and injury, as well as the levels of plasma cytokines, were examined. The levels of endothelin (ET)-1, endothelial nitric oxide synthase (eNOS), phosphorylated eNOS, inducible NOS, phosphorylated myosin light chain, nuclear factor-κBp65, Bax, Bcl-2, cleaved caspase-3, and myeloperoxidase in the graft lungs were detected.

RESULTS

Compared with the LIRI group, EPC treatment significantly increased the ratios of arterial oxygen partial pressure to fractional inspiratory oxygen and decreased the lung wet-to-dry weight ratios and protein levels in the grafts, accompanied by increasing eNOS expression and phosphorylation, but decreasing endothelin-1, inducible NOS, phosphorylated nuclear factor-kBp65, phosphorylated myosin light chain expression, and myeloperoxidase activity. EPCs reduced lung tissue damage and apoptosis associated with decreased levels of Bax and cleaved caspase-3 expression, but increased Bcl-2 expression. EPC treatment significantly reduced the levels of serum proinflammatory factors, but elevated levels of interleukin-10. In contrast, the protective effect of EPCs were mitigated and abrogated by N5-(1-iminoethyl)-l-ornithine pretreatment.

CONCLUSIONS

Data indicated that EPC ameliorated LIRI by increasing eNOS expression.

Substance P ameliorates tumor necrosis factor-alpha-induced endothelial cell dysfunction by regulating eNOS expression in vitro

OBJECTIVE

The aim of this study was to explore the beneficial effects of SP on NO production and inflammation-induced vascular endothelium cell death.

METHODS

To mimic the inflammatory environment, TNF-α was treated with HUVECs, and SP was added prior to TNF-α to determine its protective effect. WST-1 assay was performed to detect cell viability. NO level in conditioned medium was measured by Griess Reagent System. The protein level of cleaved caspase-3, eNOS, and phosphorylated Akt was detected by Western blot analysis.

RESULTS

TNF-α declined endothelial cell viability by downregulating Akt and NO production. TNF-α-induced cell death was reliably restored by NO, confirming the requirement of NO for cell survival. By contrast, pretreatment of SP attenuated TNF-α-induced cellular apoptosis, accompanied by an increase in the phosphorylation of Akt, eNOS expression, and NO production. Blockage of NK-1R, phosphorylated Akt or eNOS by CP-96345, A6730, or L-NAME entirely eliminated the effect of SP.

CONCLUSIONS

SP can protect the vascular endothelium against inflammation-induced damage through modulation of the Akt/eNOS/NO signaling pathway.

Low-density lipoprotein accumulation within the right coronary artery walls for physiological and hypertension conditions

We demonstrate how low-density lipoproteins (LDL) are transported and accumulated through walls of the coronary artery. The result of modeling is a map of the LDL concentration on the patient specific vessel. It identifies places at high risk for plague growth. Using the geometry of the same patient we compare the results of two-layer and four-layer models of LDL transport.

A Systematic Review on Natural Antioxidant Properties of Resveratrol

Polyphenols, including anthocyanins, flavonoids and stilbenes, which constitute one of the most abundant and ubiquitous groups of plant metabolites, are an integral part of the human diet. Resveratrol (3,5,4'-trihydroxystilbene), a naturally occurring polyphenol produced by some plants as a self-defence agent, has an antifungal activity. Resveratrol has been found in some plants (such as grapevine, pine and peanuts) and is considered to have beneficial effects also on human health. The number of studies on resveratrol greatly increased in PubMed database since 1997, after the anticancer effect of this molecule was first reported. The interest in resveratrol in grape was originally sparked by epidemiological studies indicating an inverse relationship between long-standing moderate consumption of red wine and the risk of coronary heart disease; this effect has been ascribed to resveratrol, which possesses diverse biochemical and physiological properties, including antiplatelet and anti-inflammatory proprieties, and provides a wide range of health benefits ranging from chemoprevention to cardioprotection. Recently, resveratrol has been described as an anti-aging compound. The consumption of resveratrol (red wine) together with a Mediterranean diet or a fast-food meal (“McDonald'sMeal”) had a positive impact on oxidized (ox-) LDL and on the expression of oxidative and inflammatory genes. Therefore, this review summarized the most important scientific data about healing and preventive potential of resveratrol, acting as cardioprotective, neuroprotective, chemopreventive and antioxidant agent.

Designing in vitro Blood-Brain Barrier Models Reproducing Alterations in Brain Aging

Blood-brain barrier (BBB) modeling in vitro is a huge area of research covering study of intercellular communications and development of BBB, establishment of specific properties that provide controlled permeability of the barrier. Current approaches in designing new BBB models include development of new (bio) scaffolds supporting barriergenesis/angiogenesis and BBB integrity; use of methods enabling modulation of BBB permeability; application of modern analytical techniques for screening the transfer of metabolites, bio-macromolecules, selected drug candidates and drug delivery systems; establishment of 3D models; application of microfluidic technologies; reconstruction of microphysiological systems with the barrier constituents. Acceptance of idea that BBB in vitro models should resemble real functional activity of the barrier in different periods of ontogenesis and in different (patho) physiological conditions leads to proposal that establishment of BBB in vitro model with alterations specific for aging brain is one of current challenges in neurosciences and bioengineering. Vascular dysfunction in the aging brain often associates with leaky BBB, alterations in perivascular microenvironment, neuroinflammation, perturbed neuronal and astroglial activity within the neurovascular unit, impairments in neurogenic niches where microvascular scaffold plays a key regulatory role. The review article is focused on aging-related alterations in BBB and current approaches to development of “aging” BBB models in vitro.