Biomarkers of NRF2 signalling: Current status and future challenges.

The cytoprotective transcription factor NRF2 regulates the expression of several hundred genes in mammalian cells and is a promising therapeutic target in a number of diseases associated with oxidative stress and inflammation. Hence, an ability to monitor basal and inducible NRF2 signalling is vital for mechanistic understanding in translational studies. Due to some caveats related to the direct measurement of NRF2 levels, the modulation of NRF2 activity is typically determined by measuring changes in the expression of one or more of its target genes and/or the associated protein products. However, there is a lack of consensus regarding the most relevant set of these genes/proteins that best represents NRF2 activity across cell types and species. We present the findings of a comprehensive literature search that according to stringent criteria identifies GCLC, GCLM, HMOX1, NQO1, SRXN1 and TXNRD1 as a robust panel of markers that are directly regulated by NRF2 in multiple cell and tissue types. We assess the relevance of these markers in clinically accessible biofluids and highlight future challenges in the development and use of NRF2 biomarkers in humans.

Transportation Noise Pollution and Cardiovascular Health.

Epidemiological studies have found that transportation noise increases the risk for cardiovascular morbidity and mortality, with solid evidence for ischemic heart disease, heart failure, and stroke. According to the World Health Organization, at least 1.6 million healthy life years are lost annually from traffic-related noise in Western Europe. Traffic noise at night causes fragmentation and shortening of sleep, elevation of stress hormone levels, and increased oxidative stress in the vasculature and the brain. These factors can promote vascular (endothelial) dysfunction, inflammation, and arterial hypertension, thus elevating cardiovascular risk. The present review focusses on the indirect, nonauditory cardiovascular health effects of noise. We provide an updated overview of epidemiological research on the effects of transportation noise on cardiovascular risk factors and disease, and mechanistic insights based on the latest clinical and experimental studies and propose new risk markers to address noise-induced cardiovascular effects in the general population. We will discuss the potential effects of noise on vascular dysfunction, oxidative stress, and inflammation in humans and animals. We will elaborately explain the underlying pathomechanisms by alterations of gene networks, epigenetic pathways, circadian rhythm, signal transduction along the neuronal-cardiovascular axis, and metabolism. We will describe current and future noise mitigation strategies. Finally, we will conduct an overall evaluation of the status of the current evidence of noise as a significant cardiovascular risk factor.

Noise annoyance due to different sources is associated with tinnitus presence and distress in the general population.

BACKGROUND: The pathophysiology of tinnitus is not yet fully understood. Although there is a large amount of evidence associating traffic noise exposure with non-auditory health outcomes, there is no evidence regarding the impact of noise annoyance on auditory disorders such as tinnitus. OBJECTIVE: Thus, we aimed to investigate the association between noise annoyance due to different sources and tinnitus presence and distress in the general population. METHODS: Data of 6813 participants from a large German population-based cohort were used (Gutenberg Health Study). Participants were asked about the presence of tinnitus and how much they were bothered by it. In addition, information on annoyance from road traffic, aircraft, railways, industrial, and neighborhood noise during the day and sleep was collected through validated questionnaires. RESULTS: The prevalence of tinnitus was 27.3%, and the predominant sources of noise annoyance in these subjects were aircraft, neighborhood, and road traffic noise. Overall, logistic regression results demonstrated consistent positive associations between annoyance due to different noise sources and prevalent risk of tinnitus with increases in odds ratios ranging from 4 to 11% after adjustment for sex, age, and socioeconomic status. Likewise, consistent increases in odds ratios were observed for tinnitus distress in subjects with prevalent tinnitus. For instance, neighborhood noise annoyance during the sleep was associated with a 26% increase in tinnitus distress (OR 1.26, 95% CI 1.13; 1.39). IMPACT: This is the first study investigating the association between noise annoyance and tinnitus presence and distress in a large cohort of the general population. Our results indicate consistent and positive associations between various sources of noise annoyance and tinnitus. These unprecedented findings are highly relevant as noise annoyance and tinnitus are widespread. The precise etiology and locus of tinnitus remain unknown, but excessive noise exposure is thought to be among the major causes. This study suggests that transportation and neighborhood noise levels thought merely to contribute to annoyance and non-auditory health effects may be sufficient to cause or exacerbate tinnitus.

Noise annoyance and cardiovascular disease risk: results from a 10-year follow-up study.

The relationship between noise annoyance and risk of cardiovascular disease (CVD) still needs to be fully elucidated. Thus, we examined the relationship between noise annoyance and CVD risk in a large population-based cohort study. Cross-sectional (N = 15,010, aged 35-74 years, baseline investigation period 2007-2012) and prospective data (5- and 10-year follow-up from 2012 to 2022) from the Gutenberg Health Study were used to examine the relationship between noise annoyance due to different sources and risk of prevalent and incident CVD comprising atrial fibrillation, coronary artery disease, myocardial infarction, stroke, chronic heart failure, peripheral artery disease, and venous thromboembolism. In cross-sectional analyses, noise annoyance was an independent risk factor for prevalent CVD, with the strongest associations seen for noise annoyance during sleep (e.g., neighborhood noise annoyance: odds ratio 1.20, 95% confidence interval 1.13-1.27, p < 0.0001). While in the 10-year follow-up, mostly positive associations (although not significant) between noise annoyance and incident CVD were observed, no indication of increased CVD risk was observed after 5 years of follow-up. Noise annoyance due to different sources was associated with prevalent CVD, whereas only weak associations with incident CVD were found. Further large-scale studies are needed to establish the relationship between noise annoyance and risk of CVD.

Role of inflammatory signaling pathways involving the CD40-CD40L-TRAF cascade in diabetes and hypertension-insights from animal and human studies.

CD40L-CD40-TRAF signaling plays a role in atherosclerosis progression and affects the pathogenesis of coronary heart disease (CHD). We tested the hypothesis that CD40L-CD40-TRAF signaling is a potential therapeutic target in hyperlipidemia, diabetes, and hypertension. In mouse models of hyperlipidemia plus diabetes (db/db mice) or hypertension (1 mg/kg/d angiotensin-II for 7 days), TRAF6 inhibitor treatment (2.5 mg/kg/d for 7 or 14 days) normalized markers of oxidative stress and inflammation. As diabetes and hypertension are important comorbidities aggravating CHD, we explored whether the CD40L-CD40-TRAF signaling cascade and their associated inflammatory pathways are expressed in CHD patients suffering from comorbidities. Therefore, we analyzed vascular bypass material (aorta or internal mammary artery) and plasma from patients with CHD with diabetes and/or hypertension. Our Olink targeted plasma proteomic analysis using the IMMUNO-ONCOLOGY panel revealed a pattern of step-wise increase for 13/92 markers of low-grade inflammation with significant changes. CD40L or CD40 significantly correlated with 38 or 56 other inflammatory targets. In addition, specific gene clusters that correlate with the comorbidities were identified in isolated aortic mRNA of CHD patients through RNA-sequencing. These signaling clusters comprised CD40L-CD40-TRAF, immune system, hemostasis, muscle contraction, metabolism of lipids, developmental biology, and apoptosis. Finally, immunological analysis revealed key markers correlated with comorbidities in CHD patients, such as CD40L, NOX2, CD68, and 3-nitrotyrosine. These data indicate that comorbidities increase inflammatory pathways in CHD, and targeting these pathways will be beneficial in reducing cardiovascular events in CHD patients with comorbidities.

Crosstalk between Oxidative Stress and Inflammation Caused by Noise and Air Pollution-Implications for Neurodegenerative Diseases.

Neurodegenerative diseases are often referred to as diseases of old age, and with the aging population, they are gaining scientific and medical interest. Environmental stressors, most notably traffic noise and air pollution, have recently come to the forefront, and have emerged as disease risk factors. The evidence for a connection between environmental risk factors and neurodegenerative disease is growing. In this review, the most common neurodegenerative diseases and their epidemiological association with traffic noise and air pollution are presented. Also, the most important mechanisms involved in neurodegenerative disease development, oxidative stress, and neuroinflammation are highlighted. An overview of the in vivo findings will provide a mechanistic link between noise, air pollution, and neurodegenerative pathology. Finally, the importance of the direct and indirect pathways, by which noise and air pollution cause cerebral damage, is discussed. More high-quality data are still needed from both epidemiological and basic science studies in order to better understand the causal connection between neurodegenerative diseases and environmental risk factors.

Vascular dysfunction and arterial hypertension in experimental celiac disease are mediated by gut-derived inflammation and oxidative stress.

AIMS: We examined the cardiovascular effects of celiac disease (CeD) in a humanized mouse model, with a focus on vascular inflammation, endothelial dysfunction, and oxidative stress. METHODS AND RESULTS: NOD.DQ8 mice genetically predisposed to CeD were subjected to a diet regime and oral gavage to induce the disease (gluten group vs. control). We tested vascular function, confirmed disease indicators, and evaluated inflammation and oxidative stress in various tissues. Plasma proteome profiling was also performed. CeD markers were confirmed in the gluten group, indicating increased blood pressure and impaired vascular relaxation. Pro-inflammatory genes were upregulated in this group, with increased CD11b+ myeloid cell infiltration and oxidative stress parameters observed in aortic and heart tissue. However, heart function remained unaffected. Plasma proteomics suggested the cytokine interleukin-17A (IL-17A) as a link between gut and vascular inflammation. Cardiovascular complications were reversed by adopting a gluten-free diet. CONCLUSION: Our study sheds light in the heightened cardiovascular risk associated with active CeD, revealing a gut-to-cardiovascular inflammatory axis potentially mediated by immune cell infiltration and IL-17A. These findings augment our understanding of the link between CeD and cardiovascular disease providing clinically relevant insight into the underlying mechanism. Furthermore, our discovery that cardiovascular complications can be reversed by a gluten-free diet underscores a critical role for dietary interventions in mitigating cardiovascular risks associated with CeD.

Vascular protein disulfide isomerase A1 mediates endothelial dysfunction induced by angiotensin II in mice.

AIM: Protein disulfide isomerases (PDIs) are involved in platelet aggregation and intravascular thrombosis, but their role in regulating endothelial function is unclear. Here, we characterized the involvement of vascular PDIA1 in angiotensin II (Ang II)-induced endothelial dysfunction in mice. METHODS: Endothelial dysfunction was induced in C57BL/6JCmd male mice via Ang II subcutaneous infusion, and PDIA1 was inhibited with bepristat. Endothelial function was assessed in vivo with magnetic resonance imaging and ex vivo with a myography, while arterial stiffness was measured as pulse wave velocity. Nitric oxide (NO) bioavailability was measured in the aorta (spin-trapping electron paramagnetic resonance) and plasma (NO2 - and NO3 - levels). Oxidative stress, eNOS uncoupling (DHE-based aorta staining), and thrombin activity (thrombin-antithrombin complex; calibrated automated thrombography) were evaluated. RESULTS: The inhibition of PDIA1 by bepristat in Ang II-treated mice prevented the impairment of NO-dependent vasodilation in the aorta as evidenced by the response to acetylcholine in vivo, increased systemic NO bioavailability and the aortic NO production, and decreased vascular stiffness. Bepristat's effect on NO-dependent function was recapitulated ex vivo in Ang II-induced endothelial dysfunction in isolated aorta. Furthermore, bepristat diminished the Ang II-induced eNOS uncoupling and overproduction of ROS without affecting thrombin activity. CONCLUSION: In Ang II-treated mice, the inhibition of PDIA1 normalized the NO-ROS balance, prevented endothelial eNOS uncoupling, and, thereby, improved vascular function. These results indicate the importance of vascular PDIA1 in regulating endothelial function, but further studies are needed to elucidate the details of the mechanisms involved.

Endogenous Nitric Oxide Can Enhance Oxidative Stress Caused by Air Pollutants and Explain Higher Susceptibility of Individuals with Inflammatory Disorders.

Air pollution causes morbidity and excess mortality. In the epithelial lining fluid of the respiratory tract, air pollutants trigger a chemical reaction sequence that causes the formation of noxious hydroxyl radicals that drive oxidative stress. For hitherto unknown reasons, individuals with pre-existing inflammatory disorders are particularly susceptible to air pollution. Through detailed multiphase chemical kinetic analysis, we show that the commonly elevated concentrations of endogenous nitric oxide in diseased individuals can increase the production of hydroxyl radicals via peroxynitrite formation. Our findings offer a molecular rationale of how adverse health effects and oxidative stress caused by air pollutants may be exacerbated by inflammatory disorders.

MCJ: A mitochondrial target for cardiac intervention in pulmonary hypertension.

Pulmonary hypertension (PH) can affect both pulmonary arterial tree and cardiac function, often leading to right heart failure and death. Despite the urgency, the lack of understanding has limited the development of effective cardiac therapeutic strategies. Our research reveals that MCJ modulates mitochondrial response to chronic hypoxia. MCJ levels elevate under hypoxic conditions, as in lungs of patients affected by COPD, mice exposed to hypoxia, and myocardium from pigs subjected to right ventricular (RV) overload. The absence of MCJ preserves RV function, safeguarding against both cardiac and lung remodeling induced by chronic hypoxia. Cardiac-specific silencing is enough to protect against cardiac dysfunction despite the adverse pulmonary remodeling. Mechanistically, the absence of MCJ triggers a protective preconditioning state mediated by the ROS/mTOR/HIF-1α axis. As a result, it preserves RV systolic function following hypoxia exposure. These discoveries provide a potential avenue to alleviate chronic hypoxia-induced PH, highlighting MCJ as a promising target against this condition.

Noise and mental health: evidence, mechanisms, and consequences.

The recognition of noise exposure as a prominent environmental determinant of public health has grown substantially. While recent years have yielded a wealth of evidence linking environmental noise exposure primarily to cardiovascular ailments, our understanding of the detrimental effects of noise on the brain and mental health outcomes remains limited. Despite being a nascent research area, an increasing body of compelling research and conclusive findings confirms that exposure to noise, particularly from sources such as traffic, can potentially impact the central nervous system. These harms of noise increase the susceptibility to mental health conditions such as depression, anxiety, suicide, and behavioral problems in children and adolescents. From a mechanistic perspective, several investigations propose direct adverse phenotypic changes in brain tissue by noise (e.g. neuroinflammation, cerebral oxidative stress), in addition to feedback signaling by remote organ damage, dysregulated immune cells, and impaired circadian rhythms, which may collectively contribute to noise-dependent impairment of mental health. This concise review linking noise exposure to mental health outcomes seeks to fill research gaps by assessing current findings from studies involving both humans and animals.

Cumulative social disadvantage and cardiovascular disease burden and mortality.

AIMS: To investigate the association between cumulative social disadvantage and cardiovascular burden and mortality in a large cohort of the general population. METHODS AND RESULTS: Cross-sectional (n = 15 010, aged 35 to 74 years, baseline investigation period 2007 to 2012) and longitudinal data (5- and 10-year follow-ups from 2012 to 2022) from the Gutenberg Health Study were used to investigate the association between individual socioeconomic status (SES, measured via a validated questionnaire) and cardiovascular disease (CVD, composite of atrial fibrillation, coronary artery disease, myocardial infarction, stroke, chronic heart failure, peripheral artery disease, and/or venous thromboembolism) risk and mortality. Subjects with prevalent CVD had a lower SES sum score, as well as lower education, occupation, and household net-income scores (all P < 0.0001). Logistic regression analysis showed that a low SES (vs. high, defined by validated cut-offs) was associated with 19% higher odds of prevalent CVD [odds ratio (OR) 1.19, 95% CI 1.01; 1.40] in the fully adjusted model. At 5-year follow-up, low SES was associated with both increased cardiovascular [hazard ratio (HR) 5.36, 2.24; 12.82] and all-cause mortality (HR 2.23, 1.51; 3.31). At 10-year follow-up, low SES was associated with a 68% higher risk of incident CVD (OR 1.68, 1.12; 2.47) as well as 86% higher all-cause mortality (HR 1.86, 1.55; 2.24). In general, the education and occupation scores were stronger related to risk of CVD and death than the household net-income score. Low SES was estimated to account for 451.45 disability-adjusted life years per 1000 people (years lived with disability 373.41/1000 and years of life lost 78.03/1000) and an incidence rate of 11 CVD cases and 3.47 CVD deaths per 1000 people per year. The population attributable fraction for CVD incidence after 5 years was 4% due to low SES. CONCLUSION: Despite universal healthcare access, cumulative social disadvantage remains associated with higher risk of CVD and mortality. Dimensions of education and occupation, but not household net income, are associated with outcomes of interest.

Low socioeconomic status is associated with higher risk of incident cardiovascular disease (CVD) and mortality in a large cohort of the general population even after comprehensive adjustment for associated variables. Education and occupation may be more important regarding CVD and mortality risk as compared to the household net income. From a public health perspective, policies should strengthen efforts to reduce socioeconomic inequalities by ensuring equal access to education and employment.

Health position paper and redox perspectives - Disease burden by transportation noise.

Transportation noise is a ubiquitous urban exposure. In 2018, the World Health Organization concluded that chronic exposure to road traffic noise is a risk factor for ischemic heart disease. In contrast, they concluded that the quality of evidence for a link to other diseases was very low to moderate. Since then, several studies on the impact of noise on various diseases have been published. Also, studies investigating the mechanistic pathways underlying noise-induced health effects are emerging. We review the current evidence regarding effects of noise on health and the related disease-mechanisms. Several high-quality cohort studies consistently found road traffic noise to be associated with a higher risk of ischemic heart disease, heart failure, diabetes, and all-cause mortality. Furthermore, recent studies have indicated that road traffic and railway noise may increase the risk of diseases not commonly investigated in an environmental noise context, including breast cancer, dementia, and tinnitus. The harmful effects of noise are related to activation of a physiological stress response and nighttime sleep disturbance. Oxidative stress and inflammation downstream of stress hormone signaling and dysregulated circadian rhythms are identified as major disease-relevant pathomechanistic drivers. We discuss the role of reactive oxygen species and present results from antioxidant interventions. Lastly, we provide an overview of oxidative stress markers and adverse redox processes reported for noise-exposed animals and humans. This position paper summarizes all available epidemiological, clinical, and preclinical evidence of transportation noise as an important environmental risk factor for public health and discusses its implications on the population level.

Deletion of adipocyte NOS3 potentiates high-fat diet-induced hypertension and vascular remodelling via chemerin.

AIMS: Obesity is an epidemic that is a critical contributor to hypertension and other cardiovascular diseases. Current paradigms suggest that endothelial nitric oxide synthase (eNOS/NOS3) in the vessel wall is the primary regulator of vascular function and blood pressure. However, recent studies have revealed the presence of eNOS/NOS3 in the adipocytes of white adipose tissues and perivascular adipose tissues (PVATs). The current understanding of the role of adipocyte NOS3 is based mainly on studies using global knockout models. The present study aimed to elucidate the functional significance of adipocyte NOS3 for vascular function and blood pressure control. METHODS AND RESULTS: We generated an adipocyte-specific NOS3 knockout mouse line using adiponectin promoter-specific Cre-induced gene inactivation. Control and adipocyte-specific NOS3 knockout (A-NOS3 KO) mice were fed a high-fat diet (HFD). Despite less weight gain, A-NOS3 KO mice exhibited a significant increase in blood pressure after HFD feeding, associated with exacerbated vascular dysfunction and remodelling. A-NOS3 KO mice also showed increased expression of signature markers of inflammation and hypoxia in the PVATs. Among the differentially expressed adipokines, we have observed an upregulation of a novel adipokine, chemerin, in A-NOS3 KO mice. Chemerin was recently reported to link obesity and vascular dysfunction. Treatment with chemerin neutralizing antibody normalized the expression of remodelling markers in the aorta segments cultured in serum from HFD-fed A-NOS3 KO mice ex vivo. CONCLUSION: These data suggest that NOS3 in adipocytes is vital in maintaining vascular homeostasis; dysfunction of adipocyte NOS3 contributes to obesity-induced vascular remodelling and hypertension.

NECAB2 is an endosomal protein important for striatal function.

Synaptic signaling depends on ATP generated by mitochondria. Dysfunctional mitochondria shift the redox balance towards a more oxidative environment. Due to extensive connectivity, the striatum is especially vulnerable to mitochondrial dysfunction. We found that neuronal calcium-binding protein 2 (NECAB2) plays a role in striatal function and mitochondrial homeostasis. NECAB2 is a predominantly endosomal striatal protein which partially colocalizes with mitochondria. This colocalization is enhanced by mild oxidative stress. Global knockout of Necab2 in the mouse results in increased superoxide levels, increased DNA oxidation and reduced levels of the antioxidant glutathione which correlates with an altered mitochondrial shape and function. Striatal mitochondria from Necab2 knockout mice are more abundant and smaller and characterized by a reduced spare capacity suggestive of intrinsic uncoupling respectively mitochondrial dysfunction. In line with this, we also found an altered stress-induced interaction of endosomes with mitochondria in Necab2 knockout striatal cultures. The predominance of dysfunctional mitochondria and the pro-oxidative redox milieu correlates with a loss of striatal synapses and behavioral changes characteristic of striatal dysfunction like reduced motivation and altered sensory gating. Together this suggests an involvement of NECAB2 in an endosomal pathway of mitochondrial stress response important for striatal function.

Acute exposure to simulated nocturnal traffic noise and cardiovascular complications and sleep disturbance-results from a pooled analysis of human field studies.

OBJECTIVES: A series of human field studies demonstrated that acute exposure to simulated nocturnal traffic noise is associated with cardiovascular complications and sleep disturbance, including endothelial dysfunction, increased blood pressure, and impaired sleep quality. A pooled analysis of these results remains to be established and is of tremendous interest to consolidate scientific knowledge. METHODS: We analyzed data from four randomized crossover studies (published between 2013 to 2021 and conducted at the University Medical Center Mainz, Germany). A total of 275 subjects (40.4% women, mean age 43.03 years) were each exposed to one control scenario (regular background noise) and at least to one traffic noise scenario (60 aircraft or train noise events) in their homes during nighttime. After each night, the subjects visited the study center for comprehensive cardiovascular function assessment, including the measurement of endothelial function and hemodynamic and biochemical parameters, as well as sleep-related variables. RESULTS: The pooled analysis revealed a significantly impaired endothelial function when comparing the two different noise sequences (0-60 vs. 60-0 simulated noise events, mean difference in flow-mediated dilation -2.00%, 95% CI -2.32; -1.68, p < 0.0001). In concordance, mean arterial pressure was significantly increased after traffic noise exposure (mean difference 2.50 mmHg, 95% CI 0.54; 4.45, p = 0.013). Self-reported sleep quality, the restfulness of sleep, and feeling in the morning were significantly impaired after traffic noise exposure (all p < 0.0001). DISCUSSION: Acute exposure to simulated nocturnal traffic noise is associated with endothelial dysfunction, increased mean arterial pressure, and sleep disturbance.