Cellular and molecular biology of aging endothelial cells

The importance of the nitric oxide-cGMP pathway in age-related cardiovascular disease: Focus on phosphodiesterase-1 and soluble guanylate cyclase

Among ageing-related illnesses, cardiovascular disease (CVD) remains the leading cause of morbidity and mortality causing one-third of all deaths worldwide. Ageing evokes a number of functional, pharmacological and morphological changes in the vasculature, accompanied by a progressive failure of protective and homeostatic mechanisms, resulting in target organ damage. Impaired vasomotor, proliferation, migration, antithrombotic and anti-inflammatory function in both the endothelial and vascular smooth muscle cells are parts of the vascular ageing phenotype. The endothelium regulates these functions by the release of a wide variety of active molecules including endothelium-derived relaxing factors such as nitric oxide, prostacyclin (PGI₂ ) and endothelium-derived hyperpolarization (EDH). During ageing, a functional decay of the nitric oxide pathway takes place. Nitric oxide signals to VSMC and other important cell types for vascular homeostasis through the second messenger cyclic guanosine monophosphate (cGMP). Maintenance of proper cGMP levels is an important goal in sustainment of proper vascular function during ageing. For this purpose, different components can be targeted in this signalling system, and among them, phosphodiesterase-1 (PDE1) and soluble guanylate cyclase (sGC) are crucial. This review focuses on the role of PDE1 and sGC in conditions that are relevant for vascular ageing.

Heme oxygenase-1 ameliorates oxidative stress-induced endothelial senescence via regulating endothelial nitric oxide synthase activation and coupling

AIM

Premature senescence of vascular endothelial cells is a leading cause of various cardiovascular diseases. Therapies targeting endothelial senescence would have important clinical implications. The present study was aimed to evaluate the potential of heme oxygenase-1 (HO-1) as a therapeutic target for endothelial senescence.

METHODS AND RESULTS

Upregulation of HO-1 by Hemin or adenovirus infection reversed H₂O₂-induced senescence in human umbilical vein endothelial cells (HUVECs); whereas depletion of HO-1 by siRNA or HO-1 inhibitor protoporphyrin IX zinc (II) (ZnPP) triggered HUVEC senescence. Mechanistically, overexpression of HO-1 enhanced the interaction between HO-1 and endothelial nitric oxide synthase (eNOS), and promoted the interaction between eNOS and its upstream kinase Akt, thus resulting in an enhancement of eNOS phosphorylation at Ser1177 and a subsequent increase of nitric oxide (NO) production. Moreover, HO-1 induction prevented the decrease of eNOS dimer/monomer ratio stimulated by H₂O₂ via its antioxidant properties. Contrarily, HO-1 silencing impaired eNOS phosphorylation and accelerated eNOS uncoupling. In vivo, Hemin treatment alleviated senescence of endothelial cells of the aorta from spontaneously hypertensive rats, through upregulating eNOS phosphorylation at Ser1177.

CONCLUSIONS

HO-1 ameliorated endothelial senescence through enhancing eNOS activation and defending eNOS uncoupling, suggesting that HO-1 is a potential target for treating endothelial senescence.

Exercise restores impaired endothelium-derived hyperpolarizing factor-mediated vasodilation in aged rat aortic arteries via the TRPV4-KCa2.3 signaling complex

Background

Aging leads to structural and functional changes in the vasculature characterized by arterial endothelial dysfunction and stiffening of large elastic arteries and is a predominant risk factor for cardiovascular disease, the leading cause of morbidity and mortality in modern societies. Although exercise reduces the risk of many age-related diseases, including cardiovascular disease, the mechanisms underlying the beneficial effects of exercise on age-related endothelial function fully elucidated.

Purpose

The present study explored the effects of exercise on the impaired endothelium-derived hyperpolarizing factor (EDHF)–mediated vasodilation in aged arteries and on the involvement of the transient receptor potential vanilloid 4 (TRPV4) channel and the small-conductance calcium-activated potassium (K_Ca2.3) channel signaling in this process.

Methods

Male Sprague-Dawley rats aged 19–21 months were randomly assigned to a sedentary group or to an exercise group. Two-month-old rats were used as young controls.

Results

We found that TRPV4 and K_Ca2.3 isolated from primary cultured rat aortic endothelial cells pulled each other down in co-immunoprecipitation assays, indicating that the two channels could physically interact. Using ex vivo functional arterial tension assays, we found that EDHF-mediated relaxation induced by acetylcholine or by the TRPV4 activator GSK1016790A was markedly decreased in aged rats compared with that in young rats and was significantly inhibited by TRPV4 or K_Ca2.3 blockers in both young and aged rats. However, exercise restored both the age-related and the TRPV4-mediated and K_Ca2.3-mediated EDHF responses.

Conclusion

These results suggest an important role for the TRPV4-K_Ca2.3 signaling undergirding the beneficial effect of exercise to ameliorate age-related arterial dysfunction.

The effects of aging and cardiovascular risk factors on microvascular function assessed by near-infrared spectroscopy

This study aimed to evaluate whether NIRS-derived reperfusion rate would detect potential differences in the forearm microvascular responsiveness between young healthy adults, and older adults free from or with cardiovascular disease (CVD) risk factors. Fifteen healthy young (age: 24.8 ± 4.0 years), seventeen older adults free of CVD risk factors (age: 67.0 ± 6.8 years), and twenty-three older adults with CVD risk factors (age: 67.9 ± 8.0 years) participated this study. Individuals underwent a blood draw and vascular occlusion test (30 s of baseline, 5 min of occlusion, and 2 min of reperfusion) and microvascular responsiveness was evaluated by using NIRS-derived tissue oxygen saturation indexes during reperfusion. A significant slower reperfusion rate and lower reperfusion magnitude was observed in older adults with CVD risk factors compared to healthy young and older adults. Although no statistical differences were found between healthy young and older individuals, there was a small (d = 0.4) effect size for reperfusion rate and moderate (d = 0.7) effects size for reperfusion magnitude when comparing these groups. In conclusion, this study demonstrated that even though the effects of aging per se on microvascular function should not be completely neglected, the CVD risk factors seem to be determinant on microvascular responsiveness impairment associated with aging.

Impact of CCR5, integrase and protease inhibitors on human endothelial cell function, stress, inflammation and senescence

BACKGROUND

Ageing HIV-infected patients present an increased incidence of cardiovascular diseases, endothelial dysfunction being an early alteration. Some protease inhibitors (PIs) have been shown to increase the risk of cardiovascular disease. We evaluated here the effects of CCR5 or integrase inhibitors as compared to PIs on endothelial functions in vitro.

METHODS

Human coronary artery endothelial cells (HCAEC) from adult and old non-HIV-infected donors were treated for 15 days with the CCR5 inhibitor maraviroc, the integrase inhibitors dolutegravir or raltegravir or the ritonavir-boosted PIs, darunavir (DRV/r) or atazanavir (ATV/r), all at C_max concentrations. We evaluated endothelial function, secretion of adhesion molecules and cytokines, inflammation, oxidative stress and senescence.

RESULTS

In endothelial cells from adult donors, we confirmed that ATV/r and DRV/r adversely affected all assessed endothelial functions and enhanced senescence, these effects being mild for DRV/r. Raltegravir had no effect and maraviroc a mild anti-inflammatory effect. Dolutegravir decreased inflammation, by inhibiting the NFκB pathway, and senescence, by repressing the p21 pathway. Moreover, HCAEC from an old donor presented, constitutively, a high level of senescence. Raltegravir mildly affected inflammation and senescence while maraviroc and dolutegravir decreased oxidative stress, inflammation and senescence and improved endothelial dysfunction.

CONCLUSIONS

We report here that the integrase inhibitor dolutegravir and the CCR5 inhibitor maraviroc reduced inflammation of human adult endothelial cells to different extents while raltegravir was neutral. Dolutegravir also reduced senescence, while PI/r increased inflammation and senescence. It is important to address the clinical relevance of these results.

Cellular senescence in cardiac diseases

Replicative capacity of somatic cells is limited. It indicates that aging also develops at the cellular level, and this is described as "cellular senescence". Senescent cells become flattened, enlarged, and irreversibly lose capacity for proliferation. Lack of specific and conclusive markers for cellular senescence makes it difficult to comprehensively define and understand this biological process especially in vivo. Molecules including p53, p21, p16^Ink4a, p38MAPK, and γH2AX, telomere attrition, enhanced signals for SA-β-gal, etc. are widely used to detect senescent cells, but these are indirect indicators of cellular senescence, and biological markers reflecting direct evidence need to be established. Genetic profiles are altered in senescent cells, letting these cells secrete pro-inflammatory molecules. Aging or age-related disorders including heart failure and atherosclerotic diseases link with an accumulation of cells undergoing cellular senescence in cardiovascular systems including heart and vessels. Senescent cells become pathogenic in most cases by mediating chronic sterile inflammation and tissue remodeling. A recent conceptual as well as technical breakthrough in this research area is "senolysis", meaning the specific elimination of senescent cells. Genetic as well as pharmacological models with senolysis contributed to reverse aging phenotypes and ameliorated pathologies in age-related disorders without enhancing the risk of tumorigenesis, and opened a new avenue for aging research. Several compounds are identified as senolytics, and some are already tested in clinical settings. It was recently reported that senolysis reverses aging phenotype in cardiovascular disorders. Generating therapies targeting suppression or elimination of senescent cells would inhibit the progression of undesirable aspects of aging, and become promising therapies for cardiac diseases.

The angiotensin-(1-7)/Mas receptor axis protects from endothelial cell senescence via klotho and Nrf2 activation

Endothelial cell senescence is a hallmark of vascular aging that predisposes to vascular disease. We aimed to explore the capacity of the renin–angiotensin system (RAS) heptapeptide angiotensin (Ang)‐(1‐7) to counteract human endothelial cell senescence and to identify intracellular pathways mediating its potential protective action. In human umbilical vein endothelial cell (HUVEC) cultures, Ang II promoted cell senescence, as revealed by the enhancement in senescence‐associated galactosidase (SA‐β‐gal+) positive staining, total and telomeric DNA damage, adhesion molecule expression, and human mononuclear adhesion to HUVEC monolayers. By activating the G protein‐coupled receptor Mas, Ang‐(1‐7) inhibited the pro‐senescence action of Ang II, but also of a non‐RAS stressor such as the cytokine IL‐1β. Moreover, Ang‐(1‐7) enhanced endothelial klotho levels, while klotho silencing resulted in the loss of the anti‐senescence action of the heptapeptide. Indeed, both Ang‐(1‐7) and recombinant klotho activated the cytoprotective Nrf2/heme oxygenase‐1 (HO‐1) pathway. The HO‐1 inhibitor tin protoporphyrin IX prevented the anti‐senescence action evoked by Ang‐(1‐7) or recombinant klotho. Overall, the present study identifies Ang‐(1‐7) as an anti‐senescence peptide displaying its protective action beyond the RAS by consecutively activating klotho and Nrf2/HO‐1. Ang‐(1‐7) mimetic drugs may thus prove useful to prevent endothelial cell senescence and its related vascular complications.

MicroRNA-126 regulates Hypoxia-Inducible Factor-1α which inhibited migration, proliferation, and angiogenesis in replicative endothelial senescence

Whereas a healthy endothelium maintains physiological vascular functions, endothelial damage contributes to the development of cardiovascular diseases. Endothelial senescence is the main determinant of endothelial dysfunction and thus of age-related cardiovascular disease. The objective of this study is to test the involvement of microRNA-126 and HIF-1α in a model of replicative endothelial senescence and the interrelationship between both molecules in this in vitro model. We demonstrated that senescent endothelial cells experience impaired tube formation and delayed wound healing. Senescent endothelial cells failed to express HIF-1α, and the microvesicles released by these cells failed to carry HIF-1α. Of note, HIF-1α protein levels were restored in HIF-1α stabilizer-treated senescent endothelial cells. Finally, we show that microRNA-126 was downregulated in senescent endothelial cells and microvesicles. With regard to the interplay between microRNA-126 and HIF-1α, transfection with a microRNA-126 inhibitor downregulated HIF-1α expression in early passage endothelial cells. Moreover, while HIF-1α inhibition reduced tube formation and wound healing closure, microRNA-126 levels remained unchanged. These data indicate that HIF-1α is a target of miRNA-126 in protective and reparative functions, and suggest that their therapeutic modulation could benefit age-related vascular disease.

Increased serum levels of soluble CD146 and vascular endothelial growth factor receptor 2 in patients with exudative age-related macular degeneration

AIM

To investigate serum levels of soluble CD146 (sCD146) and vascular endothelial growth factor receptor 2 (VEGFR2) in patients with age-related macular degeneration (AMD).

METHODS

Eighty-eight patients with exudative AMD and 45 sex- and age-matched healthy controls were enrolled in this study conducted in China. Serum samples was obtained from the patients with exudative AMD and from the controls. Serum sCD146 and VEGFR2 protein levels were measured using an enzyme-linked immunosorbent assay.

RESULTS

We found that serum sCD146 and VEGFR2 protein levels were significantly higher in the patients with exudative AMD group than in the controls (t=3.859, P<0.001 and t=3.829, P<0.001, respectively). Serum sCD146 levels were significantly higher in patients with classic choroidal neovascularization (CNV) than in those with occult CNV (t=9.899, P<0.001). There was a significant difference in the trend for exudative AMD in the highest versus lowest quartile of circulating sCD146 levels (χ ²=10.29, P=0.001). The receiver operating characteristic curve analysis showed that the area under the curve was 0.696 for sCD146 (95%CI: 0.601-0.791) with an optimum diagnostic cut-off value of 157.16 ng/mL, a sensitivity of 55.7%, and a specificity of 82.2%.

CONCLUSION

The serum sCD146 level increases and may be a biomarker for exudative AMD.

Therapeutic vascular growth in the heart

Despite tremendous efforts in preclinical research over the last decades, the clinical translation of therapeutic angiogenesis to grow stable and functional blood vessels in patients with ischemic diseases continues to prove challenging. In this mini review, we briefly present the current main approaches applied to improve pro-angiogenic therapies. Specific examples from research on therapeutic cardiac angiogenesis and arteriogenesis will be discussed, and finally some suggestions for future therapeutic developments will be presented.

Characterization of the Systemic Findings of Patients Undergoing Initiation of Anti-Vascular Endothelial Growth Factor Therapy for Diabetic Macular Edema in Routine Clinical Practice

BACKGROUND AND OBJECTIVES

Previous studies have validated that baseline visual acuity (VA) can predict a variance response to anti-vascular endothelial growth factor (VEGF) treatment. However, little is known about the initial systemic presentation of diabetic macular edema (DME) in clinical practice. The aim of this study is to report the baseline systemic findings of patients presenting with DME who received anti-VEGF in clinical practice.

PATIENTS AND METHODS

A retrospective chart review of patients with DME presenting between April 2012 and December 2016 was performed.

RESULTS

Data from 638 patients were retrieved. The average patient age was 63.1 years (±11.6 years), and 53% were male. There were 95.6% type II diabetics with an average HgA1c of 8.1% (range: 5.1% to 14.5%). Insulin use was present in 67%, biguanides in 43%, sulfonylureas in 32.8%, DDP4 inhibitors in 11.8%, thiazolidinediones in 3.9%, and D-phenylalanine derivatives in 0.94%. Hypertension was present in 78.4% of patients, cardiac comorbidities in 29.3%, peripheral vascular disease in 16.5%, and renal insufficiency in 22.6%. Patients were then split into two different cohorts based on VA (ETDRS < 70 and ETDRS ≥ 70), and variables were compared between groups.

CONCLUSION

It was shown that older age, hypertension, elevated creatinine, elevated high-density lipoprotein cholesterol, and decreased biguanide use were positively associated with worse presenting VA. [Ophthalmic Surg Lasers Imaging Retina. 2019;50:16-24.].

Central role of the p53 pathway in the noncoding-RNA response to oxidative stress

Oxidative stress plays a fundamental role in many conditions. Specifically, redox imbalance inhibits endothelial cell (EC) growth, inducing cell death and senescence. We used global transcriptome profiling to investigate the involvement of noncoding-RNAs in these phenotypes. By RNA-sequencing, transcriptome changes were analyzed in human ECs exposed to H₂O₂, highlighting a pivotal role of p53-signaling. Bioinformatic analysis and validation in p53-silenced ECs, identified several p53-targets among both mRNAs and long noncoding-RNAs (lncRNAs), including MALAT1 and NEAT1. Among microRNAs (miRNAs), miR-192-5p was the most induced by H₂O₂ treatment, in a p53-dependent manner. Down-modulated mRNA-targets of miR-192-5p were involved in cell cycle, DNA repair and stress response. Accordingly, miR-192-5p overexpression significantly decreased EC proliferation, inducing cell death. A central role of the p53-pathway was also confirmed by the analysis of differential exon usage: Upon H₂O₂ treatment, the expression of p53-dependent 5'-isoforms of MDM2 and PVT1 increased selectively. The transcriptomic alterations identified in H₂O₂-treated ECs were also observed in other physiological and pathological conditions where redox control plays a fundamental role, such as ECs undergoing replicative senescence, skeletal muscles of critical limb-ischemia patients and the peripheral-blood mononuclear cells of long-living individuals. Collectively, these findings indicate a prominent role of noncoding-RNAs in oxidative stress response.

Resveratrol attenuates hydrogen peroxide-induced aging through upregulation of autophagy in human umbilical vein endothelial cells

PURPOSE

Resveratrol (RESV; trans-3,5,4'-trihydroxystilbene) has emerged as a potential new therapeutic for age-related atherosclerotic diseases. However, the effect of RESV on cellular aging and its underlying mechanisms remain unknown. Therefore, the aim of this study was to examine whether RESV can delay cellular aging through upregulation of autophagy.

MATERIALS AND METHODS

Human umbilical endothelial vein cells (HUVECs) were divided into four groups: the control group, and the hydrogen peroxide (H2O2) alone, H2O2 + RESV pretreatment, and H2O2 + 3-methyladenine (3-MA) + RESV pretreatment intervention groups. The cell viability was evaluated by a cell counting kit-8 assay. Superoxide dismutase (SOD) activity and intracellular reactive oxygen species (ROS) levels were tested using commercial kits. Senescence-related β-galactosidase activities were detected by immunohistochemical staining. The expression levels of aging-related and autophagy-related markers, including phosphorylated Rb (p-Rb), LC3, and p62, with or without RESV were measured by Western blotting.

RESULTS

Pretreatment with 10 µM RESV increased the cell viability and SOD levels. The remarkably higher positive rate of senescence-associated β-galactosidase and increased intracellular ROS levels in the H2O2 treatment group were reversed by treatment with 10 µM RESV. As compared to the H2O2 treatment group, 10 µM RESV could upregulate autophagy through the regulation of p-Rb, LC3, and p62 levels. The anti-aging effect of RESV via an autophagy regulation mechanism was further confirmed by the suppression of these effects with 3-MA treatment.

CONCLUSION

RESV may reverse and delay the aging process of HUVECs via upregulation of autophagy and could be a candidate therapeutic for age-related atherosclerotic diseases.

Long-term stimulation of angiotensin II induced endothelial senescence and dysfunction

The role of angiotensin II (Ang II) in hypertension has been clarified, but recent studies show that aging-associated arterial changes and those with hypertension as well as atherosclerosis may have some common pathogenesis. This study aimed to clarify the effects of Ang II on endothelial senescence by establishing a replicative senescence model of human umbilical vein endothelial cells (HUVECs) in vitro. The population-doubling level (PDL) was calculated, PDL5 and PDL25 respectively referred to cells cultured for 2 days and 30 days. Compared with Ang II-treated young PDL5 cells, chronic stimulation of Ang II significantly promoted the senescence-associated β-galactosidase activity and expression of senescence-related genes p16 and p21, slowed down cell growth rate, and decreased expression of longevity-related genes sirtuin1 as well as telomerase activity in senescent PDL25 cells (all P < 0.05). Moreover, expression of pro-inflammatory cytokines and adhesion molecules were up-regulated in Ang II-treated PDL25 cells (all P < 0.05). Ang II-induced senescent progression and inflammation were attenuated by angiotensin receptor blocker valsartan. In young PDL5 cells, Ang II promoted the endothelial viability including cell proliferation, migration, angiogenesis and cell adhesion to monocytes; however, chronic stimulation of Ang II suppressed the cell viability, promoted cell adhesion and apoptosis in senescent PDL25 cells, which could be ameliorated by short-term valsartan, but long-term valsartan had no effects. In addition, Ang II-induced senescent features could be partly recovered if Ang II was stopped at PDL20. These findings suggested that chronic stimulation of Ang II can accelerate the endothelial senescence process which is implicated in aging-related atherosclerosis.

Red Blood Cell Distribution Width, Vascular Aging Biomarkers, and Endothelial Progenitor Cells for Predicting Vascular Aging and Diagnosing/Prognosing Age-Related Degenerative Arterial Diseases

The emerging evidence emphasizes red blood cell distribution width (RDW) as optimal prognostic biomarker for cardiovascular diseases. However, several clinical biases impede its clinical application. Recent recommendations suggest combining RDW with other biomarkers. Accordingly, we propose evaluating the well-recognized biomarkers of vascular aging (i.e., the leukocyte telomere length and telomerase activity, and reduced levels of endothelial progenitor cells [EPCs]) with RDW, for predicting the risk for vascular aging and onset and prognosis of age-related degenerative arterial diseases, such as sporadic ascending aorta aneurysm (AAA), characterized to have an increased incidence in old people. Consequently, in this study (and for the first time), we simultaneously investigated the relationship between RDW values, systemic inflammatory molecules, mean values of leukocyte telomere length, telomerase activity and EPCs, and the risk for vascular aging and AAA onset and prognosis. To achieve this aim, we selected 80 old and 80 young healthy subjects and 80 AAA cases. Appropriate methodologies were used for assessing blood parameters, aorta alterations, genotyping, impairment of the leukocyte telomere length, and telomerase activity. The main findings obtained demonstrated that increased RDW values along with the augmented blood levels of high-sensitive C-reactive protein and the reduced mean values of both leukocyte telomere length, telomerase activity, and EPCs are independently associated with the high risk for both vascular aging and AAA onset and prognosis. They might be used as the best predictor biomarker profile for vascular aging, and for both diagnosis and outcome of sporadic AAA.

Class II transactivator (CIITA) mediates IFN-γ induced eNOS repression by enlisting SUV39H1

Endothelial nitric oxide synthase (eNOS), selectively expressed in vascular endothelial cells, plays important roles in a range of biological and pathological processes. eNOS levels can be altered by extrinsic and intrinsic cues at the transcriptional level. Here we examined the epigenetic mechanism whereby the pro-inflammatory cytokine interferon gamma (IFN-γ) represses eNOS transcription. In response to IFN-γ treatment, there was a simultaneous down-regulation of eNOS expression and up-regulation of class II trans-activator (CIITA). Over-expression of CIITA directly repressed eNOS promoter while CIITA knockdown attenuated IFN-γ induced eNOS repression. Chromatin immunoprecipitation (ChIP) assay revealed that IFN-γ stimulation promoted CIITA occupancy on the proximal eNOS (-430/-168). Coincidently, CIITA recruitment to the eNOS promoter was paralleled by the disappearance of trimethylated histone H3K4 (H3K4Me3) and the enrichment of trimethylated H3K9 (H3K9Me3) with no significant changes in the levels of trimethylated H3K27 (H3K27Me3) or trimethylated H4K20 (H4K20Me3). In accordance, CIITA depletion was associated with the normalization of H3K4Me3 and H3K9Me3 on the eNOS promoter. Mechanistically, CIITA interacted with and enlisted the histone H3K9 trimethyltransferase SUV39H1 to the eNOS promoter to repress transcription. IFN-γ treatment augmented SUV39H1 expression and promoted SUV39H1 recruitment to the eNOS promoter in endothelial cells. Silencing of SUV39H1 abrogated eNOS repression by IFN-γ by erasing H3K9Me3 from the eNOS promoter. In conclusion, our data reveal a novel role for CIITA in endothelial cells and present SUV39H1 as a druggable target in the intervention of endothelial dysfunction.

Impact of endothelial nitric oxide synthase polymorphisms on urothelial cell carcinoma development

OBJECTIVES

Urothelial cell carcinoma (UCC), a major malignancy of the genitourinary tract, is induced through carcinogenic etiological factors. Endothelial nitric oxide synthase (eNOS) is one of the major isoforms of nitric oxide synthase and is involved in various pathophysiologic and physiologic processes. In this study, eNOS single-nucleotide polymorphisms were investigated to evaluate UCC susceptibility and clinicopathological characteristics.

MATERIALS AND METHODS

Two single-nucleotide polymorphisms of eNOS in 431 patients with UCC and 862 controls without cancer were analyzed using real-time polymerase chain reaction.

RESULTS

The results showed that 272 men with UCC having eNOS 894 G > T rs1799983 "GT + TT" variants had a high risk of developing a large tumor (T1-T4, P = 0.038). Furthermore, a correlation was observed between the expressions of eNOS and invasive tumor, metastasis and poor survival in urothelial carcinoma in The Cancer Genome Atlas data set.

CONCLUSION

Our results indicated that male patients with UCC carrying eNOS 894 G > T rs1799983 "GT + TT" genetic variants have a high risk of developing a large tumor, and eNOS polymorphisms may serve as a marker or therapeutic target in UCC treatment.

Quiescent Endothelial Cells Upregulate Fatty Acid β-Oxidation for Vasculoprotection via Redox Homeostasis

Little is known about the metabolism of quiescent endothelial cells (QECs). Nonetheless, when dysfunctional, QECs contribute to multiple diseases. Previously, we demonstrated that proliferating endothelial cells (PECs) use fatty acid β-oxidation (FAO) for de novo dNTP synthesis. We report now that QECs are not hypometabolic, but upregulate FAO >3-fold higher than PECs, not to support biomass or energy production but to sustain the tricarboxylic acid cycle for redox homeostasis through NADPH regeneration. Hence, endothelial loss of FAO-controlling CPT1A in CPT1A^ΔEC mice promotes EC dysfunction (leukocyte infiltration, barrier disruption) by increasing endothelial oxidative stress, rendering CPT1A^ΔEC mice more susceptible to LPS and inflammatory bowel disease. Mechanistically, Notch1 orchestrates the use of FAO for redox balance in QECs. Supplementation of acetate (metabolized to acetyl-coenzyme A) restores endothelial quiescence and counters oxidative stress-mediated EC dysfunction in CPT1A^ΔEC mice, offering therapeutic opportunities. Thus, QECs use FAO for vasculoprotection against oxidative stress-prone exposure.

Protective Role of Endogenous Kallistatin in Vascular Injury and Senescence by Inhibiting Oxidative Stress and Inflammation

Kallistatin was identified in human plasma as a tissue kallikrein-binding protein and a serine proteinase inhibitor. Kallistatin exerts pleiotropic effects on angiogenesis, oxidative stress, inflammation, apoptosis, fibrosis, and tumor growth. Kallistatin levels are markedly reduced in patients with coronary artery disease, sepsis, diabetic retinopathy, inflammatory bowel disease, pneumonia, and cancer. Moreover, plasma kallistatin levels are positively associated with leukocyte telomere length in young African Americans, indicating the involvement of kallistatin in aging. In addition, kallistatin treatment promotes vascular repair by increasing the migration and function of endothelial progenitor cells (EPCs). Kallistatin via its heparin-binding site antagonizes TNF-α-induced senescence and superoxide formation, while kallistatin's active site is essential for inhibiting miR-34a synthesis, thus elevating sirtuin 1 (SIRT1)/eNOS synthesis in EPCs. Kallistatin inhibits oxidative stress-induced cellular senescence by upregulating Let-7g synthesis, leading to modulate Let-7g-mediated miR-34a-SIRT1-eNOS signaling pathway in human endothelial cells. Exogenous kallistatin administration attenuates vascular injury and senescence in association with increased SIRT1 and eNOS levels and reduced miR-34a synthesis and NADPH oxidase activity, as well as TNF-α and ICAM-1 expression in the aortas of streptozotocin- (STZ-) induced diabetic mice. Conversely, endothelial-specific depletion of kallistatin aggravates vascular senescence, oxidative stress, and inflammation, with further reduction of Let-7g, SIRT1, and eNOS and elevation of miR-34a in mouse lung endothelial cells. Furthermore, systemic depletion of kallistatin exacerbates aortic injury, senescence, NADPH oxidase activity, and inflammatory gene expression in STZ-induced diabetic mice. These findings indicate that endogenous kallistatin displays a novel role in protection against vascular injury and senescence by inhibiting oxidative stress and inflammation.

Healthy lifestyle-based approaches for successful vascular aging

This review summarizes a presentation given at the 2016 Gerontological Society of America Annual Meeting as part of the Vascular Aging Workshop. The development of age-related vascular dysfunction increases the risk of cardiovascular disease as well as other chronic age-associated disorders, including chronic kidney disease and Alzheimer's disease. Healthy lifestyle behaviors, most notably regular aerobic exercise and certain dietary patterns, are considered "first-line" strategies for the prevention and/or treatment of vascular dysfunction with aging. Despite the well-established benefits of these strategies, however, many older adults do not meet the recommended guidelines for exercise or consume a healthy diet. Therefore, it is important to establish alternative and/or complementary evidence-based approaches to prevent or reverse age-related vascular dysfunction. Time-efficient forms of exercise training, hormetic exposure to mild environmental stress, fasting "mimicking" dietary paradigms, and nutraceutical/pharmaceutical approaches to favorably modulate cellular and molecular pathways activated by exercise and healthy dietary patterns may hold promise as such alternative approaches. Determining the efficacy of these novel strategies is important to provide alternatives for adults with low adherence to conventional healthy lifestyle practices for healthy vascular aging.

mTORC2 facilitates endothelial cell senescence by suppressing Nrf2 expression via the Akt/GSK-3β/C/EBPα signaling pathway

Vascular endothelial cell senescence is a leading cause of age-associated and vascular diseases. Mammalian target of rapamycin complex 2 (mTORC2) is a conserved serine/threonine (Ser/Thr) protein kinase that plays an important regulatory role in various cellular processes. However, its impact on endothelial senescence remains controversial. In this study we investigated the role and molecular mechanisms of mTORC2 in endothelial senescence. A replicative senescence model and H₂O₂-induced premature senescence model were established in primary cultured human umbilical vein endothelial cells (HUVECs). In these senescence models, the formation and activation of mTORC2 were significantly increased, evidenced by the increases in binding of Rictor (the essential component of mTORC2) to mTOR, phosphorylation of mTOR at Ser2481 and phosphorylation of Akt (the effector of mTORC2) at Ser473. Knockdown of Rictor or treatment with the Akt inhibitor MK-2206 attenuated senescence-associated β-galactosidase (β-gal) staining and expression of p53 and p21 proteins in the senescent endothelial cells, suggesting that mTORC2/Akt facilitates endothelial senescence. The effect of mTORC2/Akt on endothelial senescence was due to suppression of nuclear factor erythroid 2-related factor 2 (Nrf2) at the transcriptional level, since knockdown of Rictor reversed the reduction of Nrf2 mRNA expression in endothelial senescence. Furthermore, mTORC2 suppressed the expression of Nrf2 via the Akt/GSK-3β/C/EBPα signaling pathway. These results suggest that the mTORC2/Akt/GSK-3β/C/EBPα/Nrf2 signaling pathway is involved in both replicative and inducible endothelial senescence. The deleterious role of mTORC2 in endothelial cell senescence suggests therapeutic strategies (targeting mTORC2) for aging-associated diseases and vascular diseases.

Associations between depression, anxiety and medication adherence among patients with arterial hypertension: Comparison between persons exposed and non-exposed to radiation from the Semipalatinsk Nuclear Test Site

In this study, we investigated the association between depression, anxiety and medication adherence in patients with arterial hypertension living in East Kazakhstan region. The sample size included 795 patients, of whom 403 patients were exposed to radiation at the Semipalatinsk Nuclear Test Site from 1949 to 1989, while 395 patients were unexposed to radiation due to their very remote residence from the Site at the same period. Both exposed and unexposed patients showed no significant differences concerning body mass index, smoking habit, the presence of hypercholesterolemia, and hypertension grade. Patients with arterial hypertension previously exposed to radiation had significantly higher rates of low medication adherence, subclinical and clinical depression, situational anxiety of moderate and severe grade, and personal anxiety of moderate grade. A logistic regression analysis allowed us to identify the presence of significant positive association between medication adherence and anxiety in exposed patients (OR = 4041 (95%CI:1709-9556) p = 0.001) and marginal association (OR = 2998 (95%CI:1008-8915) p = 0.048) between the same parameters in unexposed patients. It might prove to be useful to introduce psychological and medical counseling with an emphasis on strengthening of medication adherence and to inform the local population about radiation effects and dosimetry data.

Genistein protects against ox-LDL-induced senescence through enhancing SIRT1/LKB1/AMPK-mediated autophagy flux in HUVECs

The anti-senescence activity of genistein is associated with inducing autophagy; however, the underlying mechanisms are not fully understood. In this study, human umbilical vein endothelial cells (HUVECs) were pretreated with genistein (1000 nM) for 30 min and then exposed to ox-LDL (50 mg/L) for another 12 h. The study found that genistein inhibited the ox-LDL-induced senescence (reducing the levels of P16 and P21 protein, and the activity of SA-β-gal); meanwhile, the effect of genistein was bound up with enhancing autophagic flux (increasing LC3-II, and decreasing the level of P62, p-mTOR and p-P70S6K). Moreover, SIRT1/LKB1/AMPK pathway was involved in genistein accelerating autophagic flux and mitigating senescence in HUVECs. The present study illustrated that genistein was a promising therapeutic agent to delay aging process and extend longevity.

Effects of hypoestrogenism and/or hyperaldosteronism on myocardial remodeling in female mice

We investigated the potential adverse effects of hyperaldosteronism and/or hypoestrogenism on cardiac phenotype, and examined their combined effects in female mice overexpressing cardiac aldosterone synthase (AS). We focused on some signaling cascades challenging defensive responses to adapt and/or to survive in the face of double deleterious stresses, such as Ca2+ -homeostasis, pro/anti-hypertrophic, endoplasmic reticulum stress (ER stress), pro- or anti-apoptotic effectors, and MAP kinase activation, and redox signaling. These protein expressions were assessed by immunoblotting at 9 weeks after surgery. Female wild type (FWT) and FAS mice were fed with phytoestrogen-free diet; underwent ovariectomy (Ovx) or sham-operation (Sham). Ovx increased gain weight and hypertrophy index. Transthoracic echocardiograghy was performed. Both Ovx-induced heart rate decrease and fractional shortening increase were associated with collagen type III shift. Cardiac estrogen receptor (ERα, ERβ) protein expression levels were downregulated in Ovx mice. Hypoestrogenism increased plasma aldosterone and MR protein expression in FAS mice. Both aldosterone and Ovx played as mirror effects on up and downstream signaling effectors of calcium/redox homeostasis, apoptosis, such as concomitant CaMKII activation and calcineurin down-regulation, MAP kinase inhibition (ERK1/2, p38 MAPK) and Akt activation. The ratio Bcl2/Bax is in favor to promote cell survivor. Finally, myocardium had dynamically orchestrated multiple signaling cascades to restore tolerance to hostile environment thereby contributing to a better maintenance of Ca2+ /redox homeostasis. Ovx-induced collagen type III isoform shift and its upregulation may be important for the biomechanical transduction of the heart and the recovery of cardiac function in FAS mice. OVX antagonized aldosterone signaling pathways.

Endothelial Cells: New Players in Obesity and Related Metabolic Disorders

Metabolic disorders such as obesity are accompanied by endothelial cell (EC) dysfunction and decreased vascular density. The current paradigm posits that metabolic alterations associated with obesity secondarily lead to EC dysfunction. However, in view of recent evidence reporting that EC dysfunction per se is able to cause metabolic dysregulation, this paradigm should be revisited and further elaborated. In this article we summarize current views and discuss evidence in favor of a causal role for ECs in systemic metabolic dysregulation. We also integrate and contextualize current research in a pathophysiological framework and discuss potential therapeutic strategies targeting angiogenesis to help to counteract obesity.

Shared Features of Endothelial Dysfunction between Sepsis and Its Preceding Risk Factors (Aging and Chronic Disease)

Acute vascular endothelial dysfunction is a central event in the pathogenesis of sepsis, increasing vascular permeability, promoting activation of the coagulation cascade, tissue edema and compromising perfusion of vital organs. Aging and chronic diseases (hypertension, dyslipidaemia, diabetes mellitus, chronic kidney disease, cardiovascular disease, cerebrovascular disease, chronic pulmonary disease, liver disease, or cancer) are recognized risk factors for sepsis. In this article we review the features of endothelial dysfunction shared by sepsis, aging and the chronic conditions preceding this disease. Clinical studies and review articles on endothelial dysfunction in sepsis, aging and chronic diseases available in PubMed were considered. The main features of endothelial dysfunction shared by sepsis, aging and chronic diseases were: (1) increased oxidative stress and systemic inflammation, (2) glycocalyx degradation and shedding, (3) disassembly of intercellular junctions, endothelial cell death, blood-tissue barrier disruption, (4) enhanced leukocyte adhesion and extravasation, (5) induction of a pro-coagulant and anti-fibrinolytic state. In addition, chronic diseases impair the mechanisms of endothelial reparation. In conclusion, sepsis, aging and chronic diseases induce similar features of endothelial dysfunction. The potential contribution of pre-existent endothelial dysfunction to sepsis pathogenesis deserves to be further investigated.

The cerebral endothelial cell as a key regulator of inflammatory processes in sterile inflammation

Cerebral endothelial cells accomplish numerous tasks connected to the maintenance of homeostasis of the central nervous system. They create a barrier between the central nervous system and peripheral blood and regulate mechanotransduction, vascular permeability, rheology, thrombogenesis, and leukocyte adhesion. In pathophysiological conditions (e.g., stroke or ischemia-reperfusion injury) the endothelial functions are impaired, leading to increased vascular permeability, vascular inflammation, leukocyte-endothelium interactions, and transendothelial migration, driving CNS inflammation and neuronal destruction. This review describes the current knowledge on the regulatory roles of endothelial cells in neuroinflammatory processes.

Age-dependent migratory behavior of human endothelial cells revealed by substrate microtopography

Cell migration is part of many important in vivo biological processes and is influenced by chemical and physical factors such as substrate topography. Although the migratory behavior of different cell types on structured substrates has already been investigated, up to date it is largely unknown if specimen's age affects cell migration on structures. In this work, we investigated age-dependent migratory behavior of human endothelial cells from young (≤ 31 years old) and old (≥ 60 years old) donors on poly(dimethylsiloxane) microstructured substrates consisting of well-defined parallel grooves. We observed a decrease in cell migration velocity in all substrate conditions and in persistence length perpendicular to the grooves in cells from old donors. Nevertheless, in comparison to young cells, old cells exhibited a higher cell directionality along grooves of certain depths and a higher persistence time. We also found a systematic decrease of donor age-dependent responses of cell protrusions in orientation, velocity and length, all of them decreased in old cells. These observations lead us to hypothesize a possible impairment of actin cytoskeleton network and affected actin polymerization and steering systems, caused by aging.

Potent immunosuppressive activity of a phosphodiesterase-4 inhibitor N-acylhydrazone in models of lipopolysaccharide-induced shock and delayed-type hypersensitivity reaction

Immunosuppressive drugs are widely used for the treatment of immune-mediated diseases and inflammation, but the toxicity and side effects of the available immunosuppressors make the search of new agents of great relevance. Here, we evaluated the immunomodulatory activity of an N-acylhydrazone derivative, (E)-N'-(3,4-dimethoxybenzylidene)-4-methoxybenzohydrazide (LASSBio-1386), a phosphodiesterase-4 (PDE-4) inhibitor. LASSBio-1386 inhibited lymphocyte activation in a concentration-dependent fashion, decreasing lymphoproliferation and IFN-γ and IL-2 production stimulated by anti-CD3/CD28 mAbs or concanavalin A (Con A) and inducing cell-cycle arrest in the G0/G1 phase. These effects were not blocked by RU486, a glucocorticoid receptor (GR) antagonist, indicating an effect independent of glucocorticoid receptor activation. Combination index-isobologram analysis indicates a synergistic effect between LASSBio-1386 and dexamethasone in lymphoproliferation inhibition. LASSBio-1386 presented immunomodulatory action in macrophage cultures, as observed by a significant and concentration-dependent decrease in NO and TNF-α production, an effect achieved by reducing IĸB expression and NF-κB activation. In the mouse model of endotoxic shock, LASSBio-1386 at 50 and 100 mg/kg protected 50 and 85% of mice against LPS-induced lethality, respectively. In agreement to its in vitro action, treatment with 100 mg/kg of LASSBio-1386 reduced TNF-α and IL-1β serum levels, while increased IL-6 and IL-10. Finally, LASSBio-1386 reduced the paw edema in a BSA-induced delayed-type hypersensitivity model. These findings demonstrate the immunomodulatory and immunosuppressant effects of LASSBio-1386 and indicate this molecule is a promising pharmacologic agent for immune-mediated diseases.

Comparative evaluation of cannabinoid receptors, apelin and S100A6 protein in the heart of women of different age groups

Background

Recent studies have shown a significant role of the endocannabinoid system, apelin and S100A6 protein in the regulation of cardiovascular system functioning. The aim of the study was to compare and evaluate the distribution of cannabinoid receptors (CB1 and CB2), apelin and S100A6 protein in the heart of healthy women in different age groups.

Methods

The study was conducted on the hearts of 10 women (organ donors) without a history of cardiovascular disease, who were divided into two age groups: women older than 50 years and women under 50 years of age. Paraffin heart sections were processed by immunohistochemistry for detection of cannabinoids receptors (CB1 and CB2), apelin and S100A6 protein.

Results

CB1 and CB2 immunoreactivity in the cytoplasm of cardiomyocytes in the heart of women over 50 was weaker than in younger individuals. There was also strong immunoreactivity of CB1 in intercalated discs (ICDs) of the heart, only in women over 50. The presence of this receptor in this location was not found in women under 50. Apelin- and S100A6-immunoreactivity in the cardiomyocytes was stronger in older women compared to women under 50.The CB1, apelin and S100A6 immunostaining in the endothelium of myocardial vessels was weaker in women over 50 than in younger women, while intensity of CB2- immunoreaction in coronary endothelium was similar in both groups of women.

The results of the study indicate the important role of endocannabinoids, apelin, and S100A6 protein in cardiac muscle function.

Conclusion

This report might contribute to a better understanding of the role of endocannabinoid system, apelin and S100 proteins in heart function as well as shed new light on processes involved in age-related cardiomyopathy.

Diabetic gut microbiota dysbiosis as an inflammaging and immunosenescence condition that fosters progression of retinopathy and nephropathy

The increased prevalence of type 2 diabetes mellitus (T2DM) and life expectancy of diabetic patients fosters the worldwide prevalence of retinopathy and nephropathy, two major microvascular complications that have been difficult to treat with contemporary glucose-lowering medications. The gut microbiota (GM) has become a lively field research in the last years; there is a growing recognition that altered intestinal microbiota composition and function can directly impact the phenomenon of ageing and age-related disorders. In fact, human GM, envisaged as a potential source of novel therapeutics, strongly modulates host immunity and metabolism. It is now clear that gut dysbiosis and their products (e.g. p-cresyl sulfate, trimethylamine‑N‑oxide) dictate a secretory associated senescence phenotype and chronic low-grade inflammation, features shared in the physiological process of ageing ("inflammaging") as well as in T2DM ("metaflammation") and in its microvascular complications. This review provides an in-depth look on the crosstalk between GM, host immunity and metabolism. Further, it characterizes human GM signatures of elderly and T2DM patients. Finally, a comprehensive scrutiny of recent molecular findings (e.g. epigenetic changes) underlying causal relationships between GM dysbiosis and diabetic retinopathy/nephropathy complications is pinpointed, with the ultimate goal to unravel potential pathophysiological mechanisms that may be explored, in a near future, as personalized disease-modifying therapeutic approaches.

Mechanisms of Dysfunction in the Aging Vasculature and Role in Age-Related Disease

Advancing age promotes cardiovascular disease (CVD), the leading cause of death in the United States and many developed nations. Two major age-related arterial phenotypes, large elastic artery stiffening and endothelial dysfunction, are independent predictors of future CVD diagnosis and likely are responsible for the development of CVD in older adults. Not limited to traditional CVD, these age-related changes in the vasculature also contribute to other age-related diseases that influence mammalian health span and potential life span. This review explores mechanisms that influence age-related large elastic artery stiffening and endothelial dysfunction at the tissue level via inflammation and oxidative stress and at the cellular level via Klotho and energy-sensing pathways (AMPK [AMP-activated protein kinase], SIRT [sirtuins], and mTOR [mammalian target of rapamycin]). We also discuss how long-term calorie restriction-a health span- and life span-extending intervention-can prevent many of these age-related vascular phenotypes through the prevention of deleterious alterations in these mechanisms. Lastly, we discuss emerging novel mechanisms of vascular aging, including senescence and genomic instability within cells of the vasculature. As the population of older adults steadily expands, elucidating the cellular and molecular mechanisms of vascular dysfunction with age is critical to better direct appropriate and measured strategies that use pharmacological and lifestyle interventions to reduce risk of CVD within this population.

The role of senescence, telomere dysfunction and shelterin in vascular aging

In the United States and other westernized nations, CVDs are the leading cause of death in adults over 65 years of age. Large artery stiffness and endothelial dysfunction are increased with age and age-associated arterial dysfunction is an important antecedent of CVDs. One age-associated change that may contribute to vascular dysfunction and CVD risk is an increase in the number of resident senescent cells in the vasculature. Senescent cells display a pro-oxidant, pro-inflammatory phenotype known as the SASP. However, the mechanisms that drive the SASP and the vascular aging phenotype remain elusive. A putative mechanism is the involvement of oxidative stress and inflammation in telomere function. Telomeres are the end caps of chromosomes which are maintained by a six-protein complex known as shelterin. Disruption of shelterin can uncap telomeres and induce cellular senescence. Accordingly, in this review, we propose that oxidative stress and inflammation disrupt shelterin in vascular cells, driving telomere dysfunction and that this mechanism may be responsible for the induction of SASP. The proposed mechanisms may represent some of the initial changes that lead to vascular dysfunction in advanced age.

Boysenberry polyphenol inhibits endothelial dysfunction and improves vascular health

Endothelial cells have an important role in maintaining vascular homeostasis. Age-related disorders (including obesity, diabetes, and hypertension) or aging per se induce endothelial dysfunction that predisposes to the development of atherosclerosis. Polyphenols have been reported to suppress age-related endothelial cell disorders, but their role in vascular function is yet to be determined. We investigated the influence of boysenberry polyphenol on vascular health under metabolic stress in a murine model of dietary obesity. We found that administration of boysenberry polyphenol suppressed production of reactive oxygen species (ROS) and increased production of nitric oxide (NO) in the aorta. It has been reported that p53 induces cellular senescence and has a crucial role in age-related disorders, including heart failure and diabetes. Administration of boysenberry polyphenol significantly reduced the endothelial p53 level in the aorta and ameliorated endothelial cell dysfunction in iliac arteries under metabolic stress. Boysenberry polyphenol also reduced ROS and p53 levels in cultured human umbilical vein endothelial cells (HUVECs), while increasing NO production. Uncoupled endothelial nitric oxide synthase (eNOS monomer) is known to promote ROS production. We found that boysenberry polyphenol reduced eNOS monomer levels both in vivo and in vitro, along with an increase of eNOS dimerization. To investigate the components of boysenberry polyphenol mediating these favorable biological effects, we extracted the anthocyanin fractions. We found that anthocyanins contributed to suppression of ROS and p53, in association with increased NO production and eNOS dimerization. In an ex vivo study, anthocyanins promoted relaxation of iliac arteries from mice with dietary obesity. These findings indicate that boysenberry polyphenol and anthocyanins, a major component of this polyphenol, inhibit endothelial dysfunction and contribute to maintenance of vascular homeostasis.

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.

Consensus guidelines for the use and interpretation of angiogenesis assays

The formation of new blood vessels, or angiogenesis, is a complex process that plays important roles in growth and development, tissue and organ regeneration, as well as numerous pathological conditions. Angiogenesis undergoes multiple discrete steps that can be individually evaluated and quantified by a large number of bioassays. These independent assessments hold advantages but also have limitations. This article describes in vivo, ex vivo, and in vitro bioassays that are available for the evaluation of angiogenesis and highlights critical aspects that are relevant for their execution and proper interpretation. As such, this collaborative work is the first edition of consensus guidelines on angiogenesis bioassays to serve for current and future reference.

Brg1 deficiency in vascular endothelial cells blocks neutrophil recruitment and ameliorates cardiac ischemia-reperfusion injury in mice

BACKGROUND

Increased neutrophil infiltration and the ensuing inflammatory response represent a hallmark event in cardiac ischemia-reperfusion injury (IRI). It remains poorly defined how the epigenetic machinery contributes to this process.

METHODS AND RESULTS

Here we report that mice with endothelial specific deletion of brahma related gene 1 (BRG1), a chromatin remodeling protein, exhibited amelioration when subjected to cardiac ischemia-reperfusion as evidenced by a reduction in infarct size as well as better recovery of heart function. Endothelial BRG1 deficiency also attenuated cardiac fibrosis following IRI when compared to wild type littermates. Interestingly, ablation of BRG1 in the endothelium suppressed neutrophil infiltration and down-regulated the levels of pro-inflammatory mediators in the heart following IRI. Further studies revealed that BRG1 activated the transcription of PODOCALYXIN (PODXL), an L-SELECTIN ligand crucial for neutrophil adhesion, in vascular endothelial cells in response to hypoxia-reoxygenation (HR). BRG1 knockdown by small interfering RNA abrogated HR-induced PODXL expression and blocked the adhesion of neutrophils to endothelial cells. Mechanistically, BRG1 alters the chromatin structure surrounding the PODXL promoter by interacting with JMJD2B, a histone H3K9 demethylase. Depletion of JMJD2B abrogated PODXL induction by HR and inhibited the adhesion of neutrophils to endothelial cells.

CONCLUSION

Our data suggest that trans-activation of PODXL by the BRG1-JMJD2B complex in endothelial cells may promote neutrophil infiltration and consequently the pathogenesis of cardiac ischemia-reperfusion injury.

Endothelial Cell Aging: How miRNAs Contribute?

Endothelial cells (ECs) form monolayers and line the interior surfaces of blood vessels in the entire body. In most mammalian systems, the capacity of endothelial cells to divide is limited and endothelial cells are prone to be senescent. Aging of ECs and resultant endothelial dysfunction lead to a variety of vascular diseases such as atherosclerosis, diabetes mellites, hypertension, and ischemic injury. However, the mechanism by which ECs get old and become senescent and the impact of endothelial senescence on the vascular function are not fully understood. Recent research has unveiled the crucial roles of miRNAs, which are small non-coding RNAs, in regulating endothelial cellular functions, including nitric oxide production, vascular inflammation, and anti-thromboformation. In this review, how senescent-related miRNAs are involved in controlling the functions of ECs will be discussed.

Senescent Microvesicles: A Novel Advance in Molecular Mechanisms of Atherosclerotic Calcification

Atherosclerosis, a chronic inflammatory disease that causes the most heart attacks and strokes in humans, is the leading cause of death in the developing world; its principal clinical manifestation is coronary artery disease. The development of atherosclerosis is attributed to the aging process itself (biological aging) and is also associated with the development of chronic diseases (premature aging). Both aging processes produce an increase in risk factors such as oxidative stress, endothelial dysfunction and proinflammatory cytokines (oxi-inflamm-aging) that might generate endothelial senescence associated with damage in the vascular system. Cellular senescence increases microvesicle release as carriers of molecular information, which contributes to the development and calcification of atherosclerotic plaque, as a final step in advanced atherosclerotic plaque formation. Consequently, this review aims to summarize the information gleaned to date from studies investigating how the senescent extracellular vesicles, by delivering biological signalling, contribute to atherosclerotic calcification.

Serum albumin, inflammation, and nutrition in end-stage renal disease: C-reactive protein is needed for optimal assessment

Low serum albumin (S-Alb) is a frequent feature of end-stage renal disease (ESRD) that independently predicts mortality. Serum albumin has mainly been considered a biomarker of visceral protein and immunocompetence status, fundamental to nutritional assessment. However, low S-albumin level is associated with persistent systemic inflammation and many bodies of evidence show that S-Alb has a limited role as a marker of nutritional status. We reported that a low S-Alb concentration was an independent risk factor for poor outcome in ESRD only in the presence of systemic inflammation. Moreover, the relationships between inflammatory biomarkers and outcome are confounded also by alterations in body composition (such as obese sarcopenia) and oxidative stress. Taken together, S-Alb alone should not be used as a proxy of the nutritional status in a dialysis patient. Its association with dietary intake is poor and low S-Alb values are most often non-nutritional in origin. When analyzing S-Alb to predict mortality risk in ESRD, it should always be combined with measurement of hsCRP.

The effects of donor age on organ transplants: A review and implications for aging research

Despite the considerable amount of data available on the effect of donor age upon the outcomes of organ transplantation, these still represent an underutilized resource in aging research. In this review, we have compiled relevant studies that analyze the effect of donor age in graft and patient survival following liver, kidney, pancreas, heart, lung and cornea transplantation, with the aim of deriving insights into possible differential aging rates between the different organs. Overall, older donor age is associated with worse outcomes for all the organs studied. Nonetheless, the donor age from which the negative effects upon graft or patient survival starts to be significant varies between organs. In kidney transplantation, this age is within the third decade of life while the data for heart transplantation suggest a significant effect starting from donors over age 40. This threshold was less defined in liver transplantation where it ranges between 30 and 50 years. The results for the pancreas are also suggestive of a detrimental effect starting at a donor age of around 40, although these are mainly derived from simultaneous pancreas-kidney transplantation data. In lung transplantation, a clear effect was only seen for donors over 65, with negative effects of donor age upon transplantation outcomes likely beginning after age 50. Corneal transplants appear to be less affected by donor age as the majority of studies were unable to find any effect of donor age during the first few years posttransplantation. Overall, patterns of the effect of donor age in patient and graft survival were observed for several organ types and placed in the context of knowledge on aging.

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Data on the effects of donor age upon the outcomes of organ transplantation are an underutilized resource in biogerontology

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We compiled data on the effect of donor age following liver, kidney, pancreas, heart, lung and cornea transplantation

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Older donor age is associated with worse outcomes for all the organs studied

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The donor age from which the negative effects upon survival starts to be significant varies between organs