Inflammation and Vascular Ageing: From Telomeres to Novel Emerging Mechanisms

Magnesium Supplementation Affects the Expression of Sirtuin1, Tumor Protein P53 and Endothelial Nitric Oxide Synthase Genes in Patients with Atherosclerosis: A Double-Blind, Randomized, Placebo-Controlled Trial

Magnesium seems to play a role in improving cardiovascular function, but its exact mechanism is unknown. In this study, we hypothesized that magnesium could modulate the expression of genes involved in atherosclerosis. The aim of the present investigation was to evaluate the effect of magnesium sulfate on the expression of sirtuin1 (SIRT1), tumor protein p53 (TP53), and endothelial nitric oxide synthase (eNOS) genes in patients with atherosclerosis. This study was a placebo-controlled double-blind randomized clinical trial on 56 patients with angiographically proven atherosclerosis. Participants were randomly divided into two groups receiving 300 mg/day magnesium sulfate (n = 29) and placebo (n = 27) for three months (following up every month). Fasting blood samples were taken before and after the intervention and total RNA was extracted and used to evaluate the expression level of SIRT1, TP53, and eNOS genes by Real-Time PCR. The expression of eNOS gene was significantly increased (P < 0.0001) and the expression of TP53 gene was decreased (P = 0.02) in the magnesium sulfate group compared to the placebo group. But SIRT1 gene expression was not significantly different between the two groups. Our findings demonstrate that magnesium sulfate supplementation may have a protective role against the progression of atherosclerosis through upregulation of eNOS and downregulation of TP53 gene. Trial registration: This present clinical trial has been registered in the Iranian Registry of Clinical Trials (IRCT) with the registration code of "IRCT20151028024756N3", https://www.irct.ir/trial/29097?revision=114102. Registered on 16 December 2019.

Aging biomarkers: Potential mediators of association between long-term ozone exposure and risk of atherosclerosis

BACKGROUND

Long-term exposure to ambient ozone links to aging biomarkers and increased risk for atherosclerotic cardiovascular diseases (ASCVD). However, the roles of aging biomarkers in the association of long-term exposure to ambient ozone with ASCVD are unclear.

METHODS

A total of 5298 participants completed the questionnaire and physical examination and provided biological specimens. Aging biomarkers (telomere length [TL] and mitochondrial copy number [mtDNA-CN]) were measured by using a real-time polymerase chain reaction method. The concentration of ambient ozone was assessed using a random forest model. Associations of ambient ozone or aging biomarkers with 10-year ASCVD risk were analyzed using logistic regression models. The roles of aging biomarkers in the association of ambient ozone exposure with 10-year ASCVD risk were explored by mediation analysis.

RESULTS

The adjusted odds ratios and 95% confidence interval of high 10-year ASCVD risk were 1.16 (1.08, 1.25), 0.71 (0.60, 0.85), and 0.78 (0.64, 0.96) in association with each 1-unit increment in ambient ozone (1 μg/m³ ) concentration, relative TL, and mtDNA-CN, respectively. The mediated proportion of the association between ambient ozone exposure and high 10-year ASCVD risk by TL or mtDNA-CN was 21.13% or 7.75%, respectively. The total proportion of association between ambient ozone exposure and high 10-year ASCVD risk mediated by TL plus mtDNA-CN was 21.02%.

CONCLUSIONS

Long-term exposure to ambient ozone was associated with increased 10-year ASCVD risk, and the association was partially mediated by aging biomarkers (shortened TL and decreased mtDNA-CN). This study indicated that ambient ozone pollution-related ASCVD risk might be partially explained by the telomere-mitochondrial axis of aging.

Exercise and Carotid Properties in the Young-The KiGGS-2 Study

Background: Carotid intima-media thickness (cIMT) and stiffness (cS) are predictive markers of early vascular aging and atherosclerotic risk. This study assessed, whether exercise has protective effects on carotid structure and function or on vascular risk in the young. Methods: Volume and change of exercise (recreational and organized sports participation) of German adolescents and young adults was assessed within the prospective population-study KiGGS at KiGGS-Wave-1 (2009-2012) and KiGGS-Wave-2 (2014-2017) using standardized self-reporting questionnaires. CIMT and cS were measured by real-time B-mode ultrasound sequences with semi-automated edge-detection and automatic electrocardiogram-gated quality control in 2,893 participants (14-28 years, 49.6% female). A cumulative index for atherosclerotic risk (CV-R) included z-scores of mean arterial pressure, triglycerides, total/HDL-cholesterol-ratio, body mass index, and HbA1c. Results: At KiGGS-Wave-2 cross-sectional CV-R but not cS and cIMT was lower in all exercise-groups compared to "no exercise" (B = -0.73, 95%-CI = -1.26 to 0.19, p = 0.008). Longitudinal volume of exercise was negatively associated with CV-R (B = -0.37, 95%-CI = -0.74 to 0.00, p = 0.048) but not with cS and cIMT. Cross-sectional relative risk of elevated CV-R but not cS and cIMT was lower in all exercise-groups compared to "no exercise" (RR = 0.80, 95%-CI = 0.66 to 0.98, p = 0.033). High exercise volumes were associated with lower relative risk of elevated CV-R (RR = 0.80, 95%-CI = 0.65-0.97, p = 0.021) and cS in tendency but not with cIMT. Conclusions: Increased levels of exercise are associated with a better cardiovascular risk profile in young individuals, but not with cS and cIMT. Our study confirms previous recommendations on exercise in this age group without demonstrating a clear benefit on surrogate markers of vascular health.

Inducing Energetic Switching Using Klotho Improves Vascular Smooth Muscle Cell Phenotype

The cardiovascular disease of atherosclerosis is characterised by aged vascular smooth muscle cells and compromised cell survival. Analysis of human and murine plaques highlights markers of DNA damage such as p53, Ataxia telangiectasia mutated (ATM), and defects in mitochondrial oxidative metabolism as significant observations. The antiageing protein Klotho could prolong VSMC survival in the atherosclerotic plaque and delay the consequences of plaque rupture by improving VSMC phenotype to delay heart attacks and stroke. Comparing wild-type VSMCs from an ApoE model of atherosclerosis with a flox'd Pink1 knockout of inducible mitochondrial dysfunction we show WT Pink1 is essential for normal cell viability, while Klotho mediates energetic switching which may preserve cell survival.

METHODS

Wild-type ApoE VSMCs were screened to identify potential drug candidates that could improve longevity without inducing cytotoxicity. The central regulator of cell metabolism AMP Kinase was used as a readout of energy homeostasis. Functional energetic switching between oxidative and glycolytic metabolism was assessed using XF24 technology. Live cell imaging was then used as a functional readout for the WT drug response, compared with Pink1 (phosphatase-and-tensin-homolog (PTEN)-induced kinase-1) knockout cells.

RESULTS

Candidate drugs were assessed to induce pACC, pAMPK, and pLKB1 before selecting Klotho for its improved ability to perform energetic switching. Klotho mediated an inverse dose-dependent effect and was able to switch between oxidative and glycolytic metabolism. Klotho mediated improved glycolytic energetics in wild-type cells which were not present in Pink1 knockout cells that model mitochondrial dysfunction. Klotho improved WT cell survival and migration, increasing proliferation and decreasing necrosis independent of effects on apoptosis.

CONCLUSIONS

Klotho plays an important role in VSMC energetics which requires Pink1 to mediate energetic switching between oxidative and glycolytic metabolism. Klotho improved VSMC phenotype and, if targeted to the plaque early in the disease, could be a useful strategy to delay the effects of plaque ageing and improve VSMC survival.

The relationship between telomere length and putative markers of vascular ageing: A systematic review and meta-analysis

Accelerated biological aging contributes to the evolution of cardiovascular disease. However, its influence on subclinical organ damage remains unclear. Leukocyte telomere length (LTL) is emerging as a marker of biological cardiovascular aging. We performed a systematic review and meta-analysis to assess the association between LTL and measures of end-organ damage. PubMed, Medline, Embase, Cinahl Plus, ClinicalTrials.gov, and grey literature databases were searched for studies that assessed the association of LTL with arterial pulse wave velocity (aPWV), carotid intima-media thickness (cIMT), left ventricular mass (LVM or LVMI), renal outcomes, coronary artery calcium (CAC) and presence of carotid plaques. In a sample of 7256 patients, we found that cIMT (pooled correlation coefficient (r) = -0.249; 95 %CI -0.37, -0.128) and aPWV (pooled r = -0.194; 95 % CI -0.290, -0.100) inversely correlate with LTL. Compared to aPWV, cIMT had a stronger correlation with LTL. Patients without carotid plaques had longer telomeres than patients with carotid plaques. Quantitative analyses documented LTL association with renal outcomes and CAC, but not with LVM/LVMI. Among measures of end-organ damage, cIMT and aPWV provide the most accurate information on the contribution of biological aging to the process of vascular remodeling/damage.

Inflammation, Oxidative Stress, Vascular Aging And Atherosclerotic Ischemic Stroke

Vascular aging is a crucial risk factor for atherosclerotic ischemic stroke. Vascular aging is characterized by oxidative stress, endothelial dysfunction, inflammation, intimal and media thickening, as well as the gradual development of arterial stiffness, among other pathophysiological features. Regarding oxidative stress, increased concentration of reactive oxygen and nitrogen species is linked to atherosclerotic ischemic stroke in vascular aging. Additionally, oxidative stress is associated with an inflammatory response. Inflammation is related to aging through the "inflammaging" theory, which is characterized by decreased ability to cope with a variety of stressors, in combination with an increased pro-inflammatory state. Vascular aging is correlated with changes in cerebral arteries that are considered predictors of the risk for atherosclerotic ischemic stroke. The aim of the present review is to present the role of oxidative stress and inflammation in vascular aging, as well as their involvement in atherosclerotic ischemic stroke.

Telomere Attrition and Clonal Hematopoiesis of Indeterminate Potential in Cardiovascular Disease

Clinical evidence suggests that conventional cardiovascular disease (CVD) risk factors cannot explain all CVD incidences. Recent studies have shown that telomere attrition, clonal hematopoiesis of indeterminate potential (CHIP), and atherosclerosis (telomere-CHIP-atherosclerosis, TCA) evolve to play a crucial role in CVD. Telomere dynamics and telomerase have an important relationship with age-related CVD. Telomere attrition is associated with CHIP. CHIP is commonly observed in elderly patients. It is characterized by an increase in blood cell clones with somatic mutations, resulting in an increased risk of hematological cancer and atherosclerotic CVD. The most common gene mutations are DNA methyltransferase 3 alpha (DNMT3A), Tet methylcytosine dioxygenase 2 (TET2), and additional sex combs-like 1 (ASXL1). Telomeres, CHIP, and atherosclerosis increase chronic inflammation and proinflammatory cytokine expression. Currently, their epidemiology and detailed mechanisms related to the TCA axis remain incompletely understood. In this article, we reviewed recent research results regarding the development of telomeres and CHIP and their relationship with atherosclerotic CVD.

SIRT3 protects endothelial cells from high glucose-induced senescence and dysfunction via the p53 pathway

Hyperglycemia induces endothelial cells (ECs) dysfunction and vascular complications by accelerating ECs senescence. It also induces downregulation of sirtuins (SIRTs). However, the molecular mechanism involved in the regulation of ECs senescence by SIRT3 remains unclear. Here, we showed that high glucose (HG) decreased the expression level of SIRT3 in human umbilical vein endothelial cells (HUVECs), increased the proportion of cells expressing senescence-associated galactosidase (SA-gal), and HG damaged the cell's ability to form tubule networks on Matrigel. However, transfection with adenoviral construct including SIRT3 significantly inhibited HG-induced SA-gal activity, decreased p53 acetylation level at the site Lys 320 (k320), and overexpression of SIRT3 antagonized high glucose-induced angiogenic dysfunction. Our results suggested a possible molecular mechanism involving HG-SIRT3-p53 in ECs senescence.

Role of hydrogen sulfide in cardiovascular ageing

Cardiovascular diseases are the main cause of morbidity and mortality in the Western society and ageing is a relevant non-modifiable risk factor. Morphological and functional alterations at endothelial level represent first events of ageing, inevitably followed by vascular dysfunction and consequent atherosclerosis that deeply influences cardiovascular health. Indeed, myocardial hypertrophy and fibrosis typically occur and contribute to compromise overall cardiac output. As regards the intracellular molecular mechanisms involved in the cardiovascular ageing, an intricate network is emerging, revealing a role for many mediators, including SIRT1/AMPK/PCG1α pathway, anti-oxidants factors (i.e. Nrf-2 and FOXOs) and pro-inflammatory cytokines. Thus, the search for pharmacological and non-pharmacological strategies that can promote a "healthy ageing", in order to slow down age-related machinery, are currently an exciting challenge for the biomedical research. Interestingly, hydrogen sulfide (H₂S) has been recently recognized as a new player capable to influence intracellular machinery involved in ageing and then it is view as a potential target for preventing cardiovascular diseases. Therefore, this review is focused on the role of H₂S in cardiovascular ageing, and on the evidence of the relationship between progressive decline in endogenous H₂S levels and the onset of various cardiovascular age-related diseases.

The Importance of Telomere Shortening for Atherosclerosis and Mortality

Telomeres are the protective end caps of chromosomes and shorten with every cell division. Short telomeres are associated with older age and adverse lifestyle factors. Leucocyte telomere length (LTL) has been proposed as a biomarker of biological age. The shortening of LTL with age is the result of the end-replication problem, environmental, and lifestyle-related factors. Epidemiologic studies have shown that LTL predicts cardiovascular disease, all-cause mortality, and death from vascular causes. Age appears to be an important co-variate that explains a substantial fraction of this effect. Although it has been proposed that short telomeres promote atherosclerosis and impair the repair of vascular lesions, existing results are inconsistent. Oxidative stress and chronic inflammation can both accelerate telomere shortening. Multiple factors, including homocysteine (HCY), vitamin B6, and vitamin B12 modulate oxidative stress and inflammation through direct and indirect mechanisms. This review provides a compact overview of telomere physiology and the utility of LTL measurements in atherosclerosis and cardiovascular disease. In addition, it summarizes existing knowledge regarding the impact of oxidative stress, inflammation, HCY, and B-vitamins on telomere function.

Telomere length in different metabolic categories: Clinical associations and modification potential

IMPACT STATEMENT

Metabolic disorders are known to be associated with accelerated telomere attrition. Their pathophysiological heterogeneity suggests the importance of multiple tests in examining these associations. However, oral glucose tolerance test (OGTT) has rarely been performed in such studies to date. There are few studies aimed at determining leukocyte telomere length (LTL) in different categories of impaired glucose tolerance (IGT), and those that do exist do not take into account the impaired fasting glucose (IFG)/IGT categorization. Therefore, we believe our study, when the OGTT was used, is important to the field. This testing made it possible to determine whether LTLs are associated with glucose levels in different hyperglycemic categories. Our data indicate that relationships between LTLs and IFG/IGT levels are not the same. This distinction can potentially be used in categorization of metabolic disorders and in determining the effectiveness of interventions aimed at treating diabetes and other metabolic abnormalities.

TERC Variants Associated with Short Leukocyte Telomeres: Implication of Higher Early Life Leukocyte Telomere Attrition as Assessed by the Blood-and-Muscle Model

Short leukocyte telomere length (LTL) is associated with atherosclerotic cardiovascular disease (ASCVD). Mendelian randomisation studies, using single nucleotide polymorphisms (SNPs) associated with short LTL, infer a causal role of LTL in ASCVD. Recent results, using the blood-and-muscle model, indicate that higher early life LTL attrition, as estimated by the ratio between LTL and skeletal muscle telomere length (MTL), rather than short LTL at conception, as estimated by MTL, should be responsible of the ASCVD-LTL connection. We combined LTL and MTL measurements and SNPs profiling in 402 individuals to determine if 15 SNPs classically described as associated with short LTL at adult age were rather responsible for higher LTL attrition during early life than for shorter LTL at birth. Two of these SNPs (rs12696304 and rs10936599) were associated with LTL in our cohort (p = 0.027 and p = 0.025, respectively). These SNPs, both located on the TERC gene, were associated with the LTL/MTL ratio (p = 0.007 and p = 0.037, respectively), but not with MTL (p = 0.78 and p = 0.32 respectively). These results suggest that SNPs located on genes coding for telomere maintenance proteins may contribute to a higher LTL attrition during the highly replicative first years of life and have an impact later on the development of ASCVD.

Senescence and the Impact on Biodistribution of Different Nanosystems: the Discrepancy on Tissue Deposition of Graphene Quantum Dots, Polycaprolactone Nanoparticle and Magnetic Mesoporous Silica Nanoparticles in Young and Elder Animals

PURPOSES

Senescence is an inevitable and irreversible process, which may lead to loss in muscle and bone density, decline in brain volume and loss in renal clearance. Although aging is a well-known process, few studies on the consumption of nanodrugs by elderly people were performed.

METHODS

We evaluated three different nanosystems: i) carbon based nanosystem (Graphene Quantum Dots, GQD), ii) polymeric nanoparticles and mesoporous silica (magnetic core mesoporous silica, MMSN). In previous studies, our group has already characterized GQD and MMSN nanoparticles by dynamic light scattering analysis, atomic force microscopy, transmission electron microscopy, X-ray diffraction, Raman analysis, fluorescence and absorbance. The polymeric nanoparticle has been characterized by AFM and DLS. All the nanosystems were radiolabeled with 99 m-Tc by. The in vivo biodistribution/tissue deposition analysis evaluation was done using elder (PN270) and young (PN90) mice injected with radioactive nanosystems.

RESULTS

The nanosystems used in this study were well-formed as the radiolabeling processes were stable. Biodistribution analysis showed that there is a decrease in the uptake of the nanoparticles in elder mice when compared to young mice, showing that is necessary to increase the initial dose in elder people to achieve the same concentration when compared to young animals.

CONCLUSION

The discrepancy on tissue distribution of nanosystems between young and elder individuals must be monitored, as the therapeutic effect will be different in the groups. Noteworthy, this data is an alarm that some specific conditions must be evaluated before commercialization of nano-drugs. Graphical Abstract Changes between younger and elderly individuals are undoubtedly, especially in drug tissue deposition, biodistribution and pharmacokinetics. The same thought should be applied to nanoparticles. A comprehensive analysis on how age discrepancy change the biological behavior of nanoparticles has been performed.

Association between human T cell leukemia virus type-1 (HTLV-1) infection and advanced periodontitis in relation to atherosclerosis among elderly Japanese: a cross-sectional study

Background

Human T cell leukemia virus type-1 (HTLV-1) stimulates inflammation activity. Our previous study revealed a positive association between asymptomatic HTLV-1 infection and advanced periodontitis among elderly Japanese individuals with low levels of hematopoietic activity (reflected by reticulocyte levels). Since low hematopoietic activity has been correlated with low-grade inflammation and low-grade inflammation is associated with atherosclerosis, the status of atherosclerosis could, in turn, determine the nature of this association.

Methods

To this end, a cross-sectional study of 907 elderly Japanese individuals (aged 60–99 years), who had participated in dental health check-up during the period 2016–2018, was conducted. Advanced periodontitis was defined as periodontal pocket ≥ 6.0 mm.

Results

Among the study population, 295 (32.5%) were found to have atherosclerosis defined as a carotid intima-media thickness (CIMT) of ≥ 1.1 mm. HTLV-1 infection was positively associated with advanced periodontitis in participants with atherosclerosis, but no significant associations were observed among the participants without atherosclerosis. The known risk factors’ (including reticulocyte and CIMT) adjusted odds ratio (OR) and 95% confidence interval (CI) of advanced periodontitis were OR 2.01 and 95% CI 1.06–3.81 for participants with atherosclerosis and OR 0.61 and 95% CI 0.34–1.12 for participants without atherosclerosis.

Conclusion

This study found a significant association between HTLV-1 infection and advanced periodontitis among elderly Japanese with atherosclerosis. However, this association is absent in individuals without atherosclerosis, suggesting that atherosclerosis might act as a determinant in the association between HTLV-1 infection and advanced periodontitis among elderly Japanese.