Impaired Endothelial Function Research Articles

C2CD4B Evokes Oxidative Stress and Vascular Dysfunction via a PI3K/Akt/PKCα-Signaling Pathway.

High glucose-induced endothelial dysfunction is an important pathological feature of diabetic vasculopathy. While genome-wide studies have identified an association between type 2 diabetes mellitus (T2DM) and increased expression of a C2 calcium-dependent domain containing 4B (C2CD4B), no study has yet explored the possible direct effect of C2CD4B on vascular function. Vascular reactivity studies were conducted using a pressure myograph, and nitric oxide and oxidative stress were assessed through difluorofluorescein diacetate and dihydroethidium, respectively. We demonstrate that high glucose upregulated both mRNA and protein expression of C2CD4B in mice mesenteric arteries in a time-dependent manner. Notably, the inhibition of C2CD4B expression by genetic knockdown efficiently prevented hyperglycemia-induced oxidative stress, endothelial dysfunction, and loss of nitric oxide (NO) bioavailability. Recombinant C2CD4B evoked endothelial dysfunction of mice mesenteric arteries, an effect associated with increased reactive oxygen species (ROS) and decreased NO production. In isolated human umbilical vein endothelial cells (HUVECs), C2CD4B increased phosphorylation of endothelial nitric oxide synthase (eNOS) at the inhibitory site Thr495 and reduced eNOS dimerization. Pharmacological inhibitors of phosphoinositide 3-kinase (PI3K), Akt, and PKCα effectively attenuated oxidative stress, NO reduction, impairment of endothelial function, and eNOS uncoupling induced by C2CD4B. These data demonstrate, for the first time, that C2CD4B exerts a direct effect on vascular endothelium via a phosphoinositide 3-kinase (PI3K)/Akt/PKCα-signaling pathway, providing a new perspective on C2CD4B as a promising therapeutic target for the prevention of oxidative stress in diabetes-induced endothelial dysfunction.

Thyroid Hormone Resistance Syndrome: From Molecular Mechanisms to Its Potential Contribution to Hypertension.

Thyroid hormone resistance (THR) is a rare inherited disorder that affects approximately one in every 40,000 live births. This condition arises from a mutation in the thyroid hormone receptor β, leading to reduced responsiveness of target tissues. It can result in a combination of hypothyroidism and hyperthyroidism symptoms in different tissues. The thyroid hormone is crucial for controlling blood pressure, and even small changes in its levels can have an effect on vascular resistance, cardiac performance, and heart rhythm. Both hypo- and hyperthyroidism have been associated with elevated blood pressure, underscoring the significant link between thyroid hormone sensitivity and vascular function. Considering thyroid hormone sensitivity is essential in clinical practice, particularly when managing patients with hypertension, to ensure personalized and effective treatment approaches. Monitoring thyroid function is essential during the diagnosis of hypertension, as thyroid dysfunction can often be corrected to normalize blood pressure. It's crucial to distinguish between essential hypertension and hypertension associated with a thyroid abnormality in THR. The mechanisms behind the development of hypertension in THR include reduced nitric oxide production, dysregulation of the renin-angiotensin-aldosterone system, impaired endothelial function, and mutations in the deiodinases. Physicians shouldunderstand the underlying mechanisms of THR and identify new therapeutic targets for hypertension in THR.

Associations between Aging and Vitamin D Status with Whole-Body Nitric Oxide Production and Markers of Endothelial Function

BackgroundAging and vitamin D deficiency have been associated with reduced nitric oxide (NO) synthesis and impaired endothelial function (EF) but the evidence in humans remains weak. ObjectivesTwo independent cross-sectional studies were designed to evaluate the association between age, sex, and plasma vitamin D concentrations with physiological and biochemical biomarkers of NO synthesis and EF in young and older healthy participants (Study 1) and in overweight and obese postmenopausal females (Study 2). MethodsIn Study 1, 40 young (20–49 y) and older (50–75 y) males and females (10 participants per age and sex group) were included. Resting blood pressure and ear-to-finger peripheral pulse wave velocity (PWV) were measured. A stable-isotopic method was used to determine whole-body NO production. Plasma 25-hydroxyvitamin D (25(OH)D), nitrate, nitrite, and asymmetric dimethylarginine (ADMA) concentrations were determined. In Study 2, 80 older overweight and obese females (age 61.2 ± 6.2 y, body mass index 29.5 ± 4.4 kg/m2) were recruited. Postocclusion reactive hyperemia (PORH) and peripheral PWV were measured. Plasma concentrations of 25(OH)D, nitrate, cyclic guanosine monophosphate, 3-nitrotyrosine (3-NT), endothelin-1, vascular endothelial growth factor, and ADMA were determined. ResultsIn Study 1, whole-body NO production was significantly greater in young compared with older participants (0.61 ± 0.30 μmol·h−1·kg−1 compared with 0.39 ± 0.10 μmol·h−1·kg−1, P = 0.01) but there was no evidence of a sex difference (P = 0.81). Plasma 25(OH)D concentration was not associated with PWV (r = 0.18, P = 0.28) or whole-body NO production (r = −0.20, P = 0.22). Plasma ADMA concentration was associated positively with age (r = 0.35, P = 0.03) and negatively with whole-body NO production (r = −0.33, P = 0.04). In Study 2, age was associated with lower PORH (r = −0.28, P = 0.02) and greater ADMA concentrations (r = 0.22, P = 0.04). Plasma 25(OH)D concentration was inversely associated with 3-NT concentrations (r = −0.31, P = 0.004). ConclusionsOlder age was associated with lower whole-body NO production. Plasma vitamin D concentrations were not associated with NO production or markers of EF but showed a weak, significant correlation with oxidative stress in postmenopausal overweight females.

Circadian disturbance induces erectile dysfunction by impairing endothelial function.

In order to explore the impact of circadian disturbance on erectile function, we randomly divided 24 adult male rats into groups of control (light on at 8:00 a.m. and off at 8:00 p.m.), dark/dark (DD; constant dark), light/light (LL; constant light), and shift dark/light (DL; light off at 8:00 a.m. and on at 8:00 p.m.). Four weeks later, erectile function was measured and corpora cavernosa were harvested for analysis. The maximum intracavernous pressure (mICP) and mICP/mean arterial pressure (MAP) ratio in the DD, LL, and DL groups were significantly lower than that in the control group. The LL and DL groups showed significantly attenuated endothelial nitric oxide synthase (eNOS), while DD, LL, and DL showed reduced neuronal nitric oxide synthase (nNOS) at both mRNA and protein levels. The production of nitric oxide (NO) and cyclic guanosine monophosphate (cGMP) was inhibited by altered light/dark cycles to varying degrees. Circadian disturbance impaired endothelial function and contributed to erectile dysfunction. For the core circadian elements, mRNA expression of circadian locomotor output cycles kaput (Clock) and brain/muscle aryl-hydrocarbon receptor nuclear translocator-like protein 1 (Bmal1) was elevated in the DL group, but their protein expression was not significantly changed. DD, LL, and DL increased period 1 (Per1) and Per3 levels, while LL and DL increased PER1 levels. No significant difference was found for Per2 levels, and PER2 and PER3 concentrations were not significantly changed. Moreover, LL and DL significantly increased cryptochrome-1 (CRY1) and CRY2 at both mRNA and protein levels. The altered light/dark rat model showed that circadian disturbance contributed to erectile dysfunction probably by impairing endothelial function. Meanwhile, the core circadian elements were detected in the corpora cavernosa, but these were disrupted. However, which circadian element regulates erectile function and how it works need further analysis.

Single-cell profiling reveals transcriptomic signatures of vascular endothelial cells in non-healing diabetic foot ulcers.

The treatment of diabetic foot ulcers (DFUs) poses a challenging medical problem that has long plagued individuals with diabetes. Clinically, wounds that fail to heal for more than 12 weeks after the formation of DFUs are referred to as non-healing/chronic wounds. Among various factors contributing to the non-healing of DFUs, the impairment of skin microvascular endothelial cell function caused by high glucose plays a crucial role. Our study aimed to reveal the transcriptomic signatures of non-healing DFUs endothelial cells, providing novel intervention targets for treatment strategies. Based on the GEO dataset (GSE165816), we selected DFU-Healer, DFU-Non-healer, and healthy non-diabetic controls as research subjects. Single-cell RNA transcriptomic sequencing technology was employed to analyze the heterogeneity of endothelial cells in different skin tissue samples and identify healing-related endothelial cell subpopulations. Immunofluorescence was applied to validate the sequencing results on clinical specimens. The number of endothelial cells and vascular density showed no significant differences among the three groups of skin specimens. However, endothelial cells from non-healing DFUs exhibited apparent inhibition of angiogenesis, inflammation, and immune-related signaling pathways. The expression of CCND1, ENO1, HIF1α, and SERPINE1 was significantly downregulated at the transcriptomic and histological levels. Further analysis demonstrated that healing-related endothelial cell subpopulations in non-healing DFUs has limited connection with other cell types and weaker differentiation ability. At the single-cell level, we uncovered the molecular and functional specificity of endothelial cells in non-healing DFUs and highlighted the importance of endothelial cell immune-mediated capability in angiogenesis and wound healing. This provides new insights for the treatment of DFUs.

Influence of Air Pollution Exposures on Cardiometabolic Risk Factors: a Review.

The increasing prevalence of cardiometabolic risk factors (CRFs) contributes to the rise in cardiovascular disease. Previous research has established a connection between air pollution and both the development and severity of CRFs. Given the ongoing impact of air pollution on human health, this review aims to summarize the latest research findings and provide an overview of the relationship between different types of air pollutants and CRFs. CRFs include health conditions like diabetes, obesity, hypertension etc. Air pollution poses significant health risks and encompasses a wide range of pollutant types, air pollutants, such as particulate matter (PM), nitrogen dioxide (NO2), sulfur dioxide (SO2), and ozone (O2). More and more population epidemiological studies have shown a positive correlation between air pollution and CRFs. Although various pollutants have diverse effects on specific cellular molecular pathways, their main influence is on oxidative stress, inflammation response, and impairment of endothelial function. More and more studies have proved that air pollution can promote the occurrence and development of cardiovascular and metabolic risk factors, and the research on the relationship between air pollution and CRFs has grown intensively. An increasing number of studies are using new biological monitoring indicators to assess the occurrence and development of CRFs resulting from exposure to air pollution. Abnormalities in some important biomarkers in the population (such as homocysteine, uric acid, and C-reactive protein) caused by air pollution deserve more attention. Further research is warranted to more fully understand the link between air pollution and novel CRF biomarkers and to investigate potential prevention and interventions that leverage the mechanistic link between air pollution and CRFs.

Impairment of Endothelial Function by Aerosol From Marijuana Leaf Vaporizers.

Marijuana leaf vaporizers, which heat plant material and sublimate Δ-9-tetrahydrocannabinol without combustion, are popular alternatives to smoking cannabis that are generally perceived to be less harmful. We have shown that smoke from tobacco and marijuana, as well as aerosol from e-cigarettes and heated tobacco products, impair vascular endothelial function in rats measured as arterial flow-mediated dilation (FMD). We exposed 8 rats per group to aerosol generated by 2 vaporizer systems (Volcano and handheld Yocan) using marijuana with varying Δ-9-tetrahydrocannabinol levels, in a single pulsatile exposure session of 2 s/min over 5 minutes, and measured changes in FMD. To model secondhand exposure, we exposed rats for 1 minute to diluted aerosol approximating release of uninhaled Volcano aerosol into typical residential rooms. Exposure to aerosol from marijuana with and without cannabinoids impaired FMD by ≈50%. FMD was similarly impaired by aerosols from Yocan (237 °C), and from Volcano at both its standard temperature (185 °C) and the minimum sublimation temperature of Δ-9-tetrahydrocannabinol (157 °C), although the low-temperature aerosol condition did not effectively deliver Δ-9-tetrahydrocannabinol to the circulation. Modeled secondhand exposure based on diluted Volcano aerosol also impaired FMD. FMD was not affected in rats exposed to clean air or water vapor passed through the Volcano system. Acute direct exposure and modeled secondhand exposure to marijuana leaf vaporizer aerosol, regardless of cannabinoid concentration or aerosol generation temperature, impair endothelial function in rats comparably to marijuana smoke. Our findings indicate that use of leaf vaporizers is unlikely to reduce the vascular risk burden of smoking marijuana.

16. Ethanol enhances thrombin-induced impairment of endothelial cell barrier function.

16. Ethanol enhances thrombin-induced impairment of endothelial cell barrier function.

Curcumin Attenuates Oxidative Stress-Induced Effects on TGF-β Expression and NF-κB Signaling in Bovine Aortic Endothelial Cells

Objectives: The endothelium constitutes a significant part of the vasculature. Oxidative stress, an imbalance between the generation of reactive oxygen species (ROS) and the antioxidant defense system, contributes to the impairment of endothelial function. ROS regulate several signaling pathways, such as transforming growth factor β (TGF-β) and nuclear factor kappa B (NF-κB). This study aimed to investigate the effects of curcumin, a polyphenol with antioxidant properties, on these two molecules in endothelial cells treated with hydrogen peroxide (H2 O2 ).
 Methods: Cultured Bovine aortic endothelial cells (BAECs) were treated with different concentrations of H2 O2 (20 µM, 40 µM, and 200μM) for 1 and 24 hours in the absence and presence of curcumin. TGF-β expression was detected by quantitative real-time PCR analysis, and phosphorylation of NF-κB-p65 was examined by western blot.
 Results: H2 O2 up-regulates TGF-β mRNA expression and induces the phosphorylation of the p65 subunit of NF-kB in a dose-dependent manner in BAECs. Curcumin inhibited both H2 O2 -stimulated TGF-β expression and phosphorylation of NF-κB-p65 in these cells.
 Conclusion: The findings demonstrate that curcumin reduces TGF-β mRNA expression and inhibits NFκB-p65 phosphorylation in endothelial cells.

Exercise for Chronic Kidney Disease: Effect on Vascular and Cardiopulmonary Function.

Patients with chronic kidney disease (CKD) have an exacerbated prevalence of cardiovascular disease (CVD). Vascular dysfunction, characterized by impaired endothelial function and arterial stiffness, and markedly low cardiorespiratory fitness levels are hallmark manifestations of the disease that contribute to the CVD burden. Despite advancements in blood pressure and lipid lowering pharmacological therapies, CVD remains highly prevalent across the spectrum of CKD. This highlights a stagnation in effective clinical strategies to improve cardiovascular health and reinforces critical need for adjuvant lifestyle strategies such as physical activity and exercise training to be incorporated into routine clinical care. This narrative review provides an overview of the known effects of exercise on cardiovascular and cardiopulmonary function across the spectrum of CKD. The physiological mechanisms of cardiovascular dysfunction that serve as exercise specific therapeutic targets are highlighted and future perspectives are discussed.

Impaired retinal micro-vascular function in patients with atrial fibrillation

BackgroundCardiovascular (CV) risk factors and CV diseases, in particular heart failure, are strongly associated with impaired microvascular retinal endothelial function. Whether atrial fibrillation (AF) contributes to vascular dysfunction is not clear. Therefore, the aim of this study was to investigate the impact of AF on retinal microvascular function. MethodsIn this study, vascular function was measured non-invasively with flicker-light induced vasodilatation of retinal arterioles (FIDart%). Patients with a history of AF and risk factors for heart failure (HF) or heart failure (n = 69; age 67.9 ± 9.2 years, 71% male, 35% HFrEF, 56% paroxysmal, 25% persistent, 19% permanent AF), as well as age, sex and ejection fraction matched patients with absent history of AF (n = 66; age 63.4 ± 10.6 years, 67% male, 47% HFrEF) were included. Patients with AF were further divided into those with paroxysmal AF (in sinus rhythm – AFSR: n = 38, age 71.4 ± 9.2, 73% male), and those with AF at the time of the study visit. ResultsRetinal microvascular function was impaired in patients with AF compared to patients without AF (FIDart% 1.1% [0.3–2.8] vs. 2.7% [1.3–5.1], p < 0.001). Patients currently in AF have poorer retinal microvascular function (FIDart% 0.8% [0.1–1.9) compared to patients with a history of AF but currently in SR at the time of retinal function measurement (1.5% [0.6–4.9] p = 0.017). In patients with AF, impaired retinal vascular function was independently associated with larger left atrial volume (mean 49.8 ± 18.4), even after correction for confounding factors in different models (SCR = -0. 251 to −0.256, p = 0.035–0.01). ConclusionsAF in patients with heart failure is associated with impaired vascular function, even if currently in sinus rhythm. The association of retinal microvascular dysfunction with left atrial volume, a surrogate for elevated cardiac filling pressures, may further highlight the important interplay between the vasculature and elevated filling pressures in the development of AF.

Innate Immune System Regulated by Stimulator of Interferon Genes, a Cytosolic DNA Sensor, Regulates Endothelial Function.

Background Sterile inflammation caused by metabolic disorders impairs endothelial function; however, the underlying mechanism by which hyperglycemia induces inflammation remains obscure. Recent studies have suggested that stimulator of interferon genes (STING), a key cytosolic DNA sensor in the innate immune system, contributes to the pathogenesis of inflammatory diseases. This study examines the role of the STING in endothelial dysfunction in streptozotocin-induced diabetic mice. Methods and Results Injection of streptozotocin promoted the expression of STING and DNA damage markers in the aorta of wild-type mice. Streptozotocin elevated blood glucose and lipid levels in both wild-type and STING-deficient mice, which showed no statistical differences. Genetic deletion of STING ameliorated endothelial dysfunction as determined by the vascular relaxation in response to acetylcholine (P<0.001) and increased endothelial nitric oxide synthase phosphorylation in the aorta (P<0.05) in STZ-injected mice. Endothelium-independent vascular response to sodium nitroprusside did not differ. Treatment with a direct STING agonist, cyclic GMP-AMP, or mitochondrial DNA increased inflammatory molecule expression (eg, VCAM1 and IFNB) and decreased endothelial nitric oxide synthase phosphorylation in human umbilical vein endothelial cells, partially through the STING pathway. Cyclic GMP-AMP significantly impaired endothelial function of aortic segments obtained from wild-type mice, which was ameliorated in the presence of C-176, a STING inhibitor, or a neutralizing interferon-β antibody. Furthermore, the administration of C-176 ameliorated endothelial dysfunction in STZ-induced diabetic mice (P<0.01). Conclusions The DNA damage response regulated by STING impairs endothelial function. STING signaling may be a potential therapeutic target of endothelial dysfunction caused by hyperglycemia.

Fat intake impairs the recovery of endothelial function following mental stress in young healthy adults.

Mental stress has been identified as a trigger of cardiovascular events. A single episode of stress can induce acute impairments in endothelial function in healthy adults. Importantly, during stressful periods, individuals often resort to unhealthy behaviors, such as increased consumption of high-fat foods, which is also known to negatively impact endothelial function. Therefore, this study examined whether consumption of a high-fat meal would further exacerbate the negative effect of mental stress on vascular function. In a randomized, counterbalanced, cross- over, postprandial intervention study, 21 healthy males and females ingested a high-fat (56.5 g fat) or a low-fat (11.4 g fat) meal 1.5 h before an 8-min mental stress task (Paced-Auditory-Serial-Addition-Task, PASAT). Plasma triglyceride (TAG) concentration was assessed pre-and post-meal. Forearm blood flow (FBF), blood pressure (BP), and cardiovascular activity were assessed pre-meal at rest and post-meal at rest and during stress. Endothelial function, measured by brachial flow-mediated dilatation (FMD) was assessed pre-meal and 30 and 90 min following mental stress. Plasma TAG concentration was significantly increased following the high-fat meal compared to the low-fat condition. Mental stress induced similar increases in peripheral vasodilation, BP, and cardiovascular activity, and impaired FMD 30 min post-stress, in both conditions. FMD remained significantly impaired 90 min following stress in the high-fat condition only, suggesting that consumption of fat attenuates the recovery of endothelial function following mental stress. Given the prevalence of fat consumption during stressful periods among young adults, these findings have important implications for dietary choices to protect the vasculature during periods of stress.

SGLT2 expression in the left ventricle of cardiac patients is correlated with low-grade inflammation involving the pro-oxidant AT1R/NADPH oxidases/SGLT2 crosstalk: potential role in heart failure

Abstract Introduction Clinical studies showed that sodium-glucose co-transporter2 inhibitors (SGLT2i) have beneficial effects in heart failure patients regardless of ejection fraction and diabetes. Such cardiac diseases are often characterized by low-grade inflammation and impaired endothelial coronary microcirculation function. Recently, angiotensin II and TNF-α were shown to induce SGLT2 expression in endothelial cells (ECs) to sustain oxidative stress leading to endothelial dysfunction. However, the role and function of SGLT2 in the human left ventricle (LV) remain unclear. Therefore, this study evaluated the expression of SGLT2 in the LV of patients with cardiac diseases and, if so, determined the cellular localization, the underlying mechanism and the functional role. Methods Human LV biopsies were collected from 20 patients subjected to valve surgery at the Nouvel Hôpital Civil, Strasbourg, France. Expression levels of targets were determined by RT-qPCR and Western blot analysis, the in situ tissue localization by immunofluorescence (IF) staining and oxidative stress by dihydroethidium staining. Results RT-qPCR analysis of LV revealed variable SGLT1 and SGLT2 mRNA levels with no significant correlation. However, SGLT2 mRNA expression showed a positive correlation with those of pro-inflammatory markers (IL-1ß, IL-6, TNF-α, MCP-1 and CD68), AT1R, and VCAM-1. Western blot analysis confirmed the heterogenous SGLT2 protein expression level in LV with a difference up to 3.5-fold among the specimens. SGLT2 protein levels showed a positive correlation with markers of oxidative stress (phospho-p65 NF-κB, AT1R, nitrotyrosine) and markers of ECs activation (VCAM-1, ICAM-1), and a negative correlation with levels of eNOS. Further, immunofluorescence analysis of LV cryosections showed SGLT2 staining in the endothelium of the coronary microcirculation, as indicated by its co-localization with the endothelial cell marker CD31, and throughout the heart tissue. SGLT2 signals were also observed in areas showing IF signals for TNF-α, phospho-p65 NF-κB, CD68 and VCAM-1 suggesting that SGLT2 expression is localized to sites of inflammation. LV specimens with high SGLT2 protein levels showed elevated levels of oxidative stress, which were inhibited by N-acetylcysteine, VAS-2870, perindoprilat, losartan, empagliflozin, and infliximab. Conclusions The findings indicate that endothelial and cardiac SGLT2 expression in the LV of cardiac patients is associated with low-grade inflammation and oxidative stress. They further indicate that the pro-inflammatory cytokines/AT1R/NAPDH oxidases/SGLT2 crosstalk contributes to sustain a pro-oxidant state. Thus, SGLT2 inhibitors might ameliorate HF by mitigating the low-grade inflammatory-related pro-oxidant state and, hence, preserve the crucial endothelial control of the cardiomyocyte function in the LV.

Increased pro-remodeling and pro-thrombotic responses in the left compared to the right atrial appendage: role of low-grade inflammation and the AT1R/NADPH oxidases/SGLT2 pro-oxidant pathway

Abstract Introduction In atrial fibrillation (AF), there is a complex interplay between arrhythmia burden and cardiovascular risk factors leading to left atrial remodeling, an increased risk of stroke and heart failure. Most thrombi get formed in the atrial appendage. Several studies suggested that sodium-glucose cotransporter 2 inhibitors (SGLT2i), besides showing major benefits on heart failure, might lower the risk of incident AF. Therefore, we examined the expression level of SGLT2 in human right and left atrial appendages (RAA, LAA) and determined its role in pro-oxidant, pro-fibrotic and pro-thrombotic responses. Methods Human RAA and LAA were collected from patients undergoing cardiac surgery at a university hospital. The LAA was cut into a proximal part (low stasis, high shear) and a distal part (high stasis, low shear). The level of reactive oxygen species (ROS) was determined using dihydroethidium, mRNA and protein expression levels by RT-qPCR, and Western blot analysis and immunofluorescence, respectively, and the level of fibrosis by Sirius red staining. Results The distal LAA had higher mRNA levels of ICAM-1 and p53, and protein levels of ICAM-1, AT1R, p53, p21 and tissue factor than the proximal LAA. LAA displayed higher mRNA and protein levels of SGLT2 and SGLT1, pro-adhesive, pro-thrombotic, pro-remodeling, pro-fibrotic and senescence markers, and components of the angiotensin system, in addition to IL-1 mRNA levels and p-p65 NF-kB protein levels compared to RAA. These responses were associated with higher levels of oxidative stress, nitrotyrosine and fibrosis. SGLT2 immunofluorescence signals in distal LAA were colocalized with those of CD31, CD68, TNF-α and troponin T. Oxidative stress levels in distal and proximal LAA and RAA were reduced by inhibitors of NADPH oxidases, ACE1 and SGLT2, an AT1R antagonist, and by a TNF-α neutralizing antibody whereas NG-nitro-L-Arginine methyl ester, the non-selective NO synthase inhibitor, inhibited ROS in distal and proximal LAA without affecting RAA. In addition, the level of TNF-α in LAA was positively correlated to the indexed LA volume indicating a link between inflammation and remodeling. Conclusions The distal part of the LAA of patients undergoing heart surgery showed greater impaired endothelial function and senescence associated with more pronounced pro­-oxidant, pro­-remodeling and pro-­inflammatory responses than the proximal part and the RAA. These responses were associated with an increased expression level of SGLT 2 in endothelial cells, cardiomyocytes, and macrophages in areas showing an inflammatory response. Moreover, the pro-oxidant signal was sensitive to inhibitors of the local angiotensin system, NO synthase, SGLT2 and TNF-α. Thus, the AT1R/NADPH oxidases/SGLT2 pathway appears as an interesting target to blunt the stimulatory pro-oxidant signal in cardiac tissues affected by low-grade inflammation that leads to remodeling and fibrosis.

Novel endothelial-enriched long non-coding RNA AL590004.3 (IRENE) is dysregulated in HFpEF and regulates endothelial enhancement of cardiomyocyte function

Abstract Background Heart failure with preserved ejection fraction (HFpEF) is the most prevalent form of HF to date. However, there is a lack of medication which stages HFpEF as an unmet clinical need. HFpEF is characterized by cardiac microvascular dysfunction, promoted by co-morbidities-associated low-grade pro-inflammatory state. We have shown that cardiac endothelial cells regulate cardiomyocyte relaxation, which is impaired when endothelial cells are inflamed. Long non-coding RNAs (lncRNAs) have been implicated in various cardiovascular diseases. However, their role in HFpEF is unknown. Here, we discovered a novel lncRNA AL590004.3 which is significantly reduced in the heart of patients with HFpEF. We hypothesized that AL590004.3 is important for cardiac endothelial function, and dysregulation of endothelial AL590004.3 impairs cardiomyocyte relaxation. Methods and results We demonstrated that AL590004.3 is significantly downregulated (∼7 fold, p&amp;lt;0.001) in HFpEF as assessed by in silico analysis of RNA sequencing of HFpEF patient cardiac biopsies. To assess the tissue distribution, we performed RNA sequencing comparing cells from various tissues and found the highest expression of AL590004.3 in the cardiac microvascular endothelial cells (CMECs), indicating its importance in cardiac endothelial cell biology. The expression of AL590004.3 was reduced when CMECs were exposed to pro-inflammatory cytokine TNFα and IL1β, indicating the detrimental effect of inflammation, as displayed by patients with HFpEF. Further, replicative senescent of CMECs led to reduced AL590004.3 expression (2 fold, p&amp;lt;0.005), showing the deleterious contribution of ageing, similar to what occurs in HFpEF patients. We showed that AL590004.3 is mostly expressed in the chromatin fraction (∼90%) of CMECs, suggesting its function in chromatin modification. To assess the function of AL590004.3, we performed loss-of-function. Using endothelial-cardiomyocyte co-culture set-up, we showed silencing of AL590004.3 in CMECs impaired endothelial function to enhance cardiomyocyte relaxation (∼1.5 fold, p&amp;lt;0.01). To dissect the molecular mechanism, we performed RNA sequencing of CMECs devoid of AL590004.3 and revealed four protein-coding genes (PXDC1, FAM50, ECI2, PRPF4B) that are differentially co-regulated, indicating their potential as protein-binding partners, which warrant further investigation. Conclusion We showed that AL590004.3 is a cardiac endothelial cell-specific lncRNA that is significantly downregulated in cardiac biopsy from HFpEF patients. AL590004.3 is important for cardiac endothelial cell function as loss-of-function in CMECs impaired endothelial enhancement of cardiomyocyte relaxation. Herewith, we name this lncRNA Important for the Regulation of ENdothelial function in HFpEF (IRENE).

Abstract 14589: Impairment of Endothelial Function by Chronic Cannabis Use: An Interim Analysis of the CANDIDE Study

Background: Increasing cannabis legalization has led to a surge in cannabis use. To understand the consequences for cardiovascular health, we have initiated the CANnabis: Does It Damage Endothelium (CANDIDE) study. Here, we report results of an interim analysis. Aims: To investigate the effects of chronic cannabis product use on endothelial function. Approach: We recruited 44 healthy non-tobacco smokers/vapers, 21-50 yrs, in 3 groups based on chronic cannabis use: cannabis smokers, THC edible users, and nonusers. Participants underwent assessment of brachial artery flow-mediated dilation (FMD) and carotid-femoral pulse wave velocity (PWV). Human umbilical vein endothelial cells (ECs) were exposed to sera from each individual with and without VEGF to determine serum effects on endothelial NO production. Human lung microvascular ECs were also exposed to the individual sera and cell permeability was measured by electric cell-substrate impedance sensing. Results: FMD and VEGF-stimulated NO levels were both significantly lower in cannabis smokers than nonusers (5.7±3.3% vs 12.0±8.0%, p=.037, and 1.1±0.3 nM vs 1.5±0.3 nM, p=.018, respectively; figure), comparable effects to what we have reported for tobacco smokers. In contrast, FMD, but not VEGF-stimulated NO levels, was lower in the THC edible users than nonusers (5.0±4.1% vs 12.0±8.0%, p=.031, and 1.6±0.3 nM vs 1.5±0.3 nM, p=.54). There were no significant differences in other functional properties (p&gt;.48). CD31 and IL-1β, which are circulating inflammatory biomarkers that we showed are elevated in tobacco smokers, were not elevated in cannabis smokers. The inflammatory biomarker PTX3 was lower in cannabis smokers than nonusers (p=.038). Conclusion: Chronic cannabis use impairs endothelial function but may reduce inflammation. Our findings suggest that the impairment caused by smoking cannabis vs edible THC use occurs via distinct mechanisms differing in the involvement of endothelial NO production.

Abstract 12425: Stim1 Deletion in Treg Cell Protects From HFpEF Pathogenesis

Introduction: Heart failure with preserved ejection fraction (HFpEF) is a cardiovascular disease that remains untreatable in its pathogenesis. Therefore, there is a critical need to uncover the cellular and molecular mechanisms underlying HFpEF pathogenesis and identify potential targets for treatment that can enhance cardiac function and restrict disease progression. Previous studies have shown that Treg cells are crucial in hypertension-induced cardiovascular complications and metabolic dysregulation. Moreover, the function of Stromal interaction molecule 1 (STIM1) varies depending on the cell type. Hypothesis: We hypothesize that the deletion of STIM1 in Treg cells can protect against the development of HFpEF and its associated conditions. Methods: Male mice aged eight weeks (Stim1 flx/flx and Treg Stim1-/- ) were divided into four groups: control groups receiving a standard diet and water for five weeks, and HFpEF groups fed a high-fat diet (HFD) and N[w]-nitro-l-arginine methyl ester (L-NAME - 0.5g/L) in the drinking water for five weeks. Various measurements and assessments were conducted, including echocardiography, evaluations of metabolism and hypertension, analysis of heart and kidney injury markers, and assessment of vascular endothelial function. Results: After five weeks, Stim1 flx/flx mice subjected to HFD and L-NAME displayed evidence of HFpEF, including hypertension, metabolic disorders, cardiac hypertrophy with fibrosis, kidney injury with fibrosis, impaired exercise tolerance and vascular endothelial function, increased body weight and E/E' ratio, reduced cardiac index, and unchanged ejection fraction. Interestingly, Treg Stim1-/- mice were protected against HFD and L-NAME-induced HFpEF and its associated pathologies. Conclusions: These findings underscore the significance of targeting STIM1 in Treg cells to protect from the development and pathogenesis of HFpEF.

Impaired cardiorespiratory fitness and endothelial function after SARS-CoV-2 infection in a sample of mainly immunocompromised youth.

This study aimed to compare cardiopulmonary fitness and endothelial function 6 months after hospital diagnosis in a sample mainly comprising immunocompromised patients with confirmed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection versus noninfected controls. Youth (n = 30; age: 14 yr; 60% females) with confirmed SARS-CoV-2 seen in a tertiary hospital of Sao Paulo, Brazil, were matched by propensity score based on BMI, age, sex, and pre-existing diseases with a control group who had not been tested positive for SARS-CoV-2 infection (n = 30; age: 15 yr; 50% females). Cardiopulmonary fitness (by means of a cardiopulmonary exercise test: CPET) and brachial flow-mediated dilation (%b-FMD) were assessed 3-6 mo after diagnosis. Patients were matched by propensity score based on BMI, age, sex and pre-existing diseases, if any, with a control group who had not been tested positive for SARS-CoV-2. Compared with controls, patients with COVID-19 showed reduced ventilatory anaerobic threshold (VAT) and peak exercise time and minute ventilation/maximum voluntary ventilation (V̇e/MVV) (all P < 0.01). Brachial endothelial function variables were all adjusted for body surface area (BSA). Patients with COVID-19 had decreased %b-FMD (3.6 vs. 5.4; P = 0.03) mean and positive flow (P = 0.02 and P = 0.03, respectively) versus controls. Adjusted linear regression models exploring associations between CPET variables, %b-FMD and the potential predictors post-COVID-19 syndrome, number of symptoms, hospitalization, and COVID severity did not detect significant associations, except for total shear rate in hospitalization (coefficient: -65.07 [95%CI -119.5;-10.5], P = 0.02). Immunocompromised and previously healthy children and adolescents with COVID-19 presented with impaired exercise capacity and endothelial dysfunction when compared with their noninfected counterparts, but the mechanisms remain unknown.NEW & NOTEWORTHY COVID-19 appeared to impair recovery of exercise capacity and endothelial function in a sample mainly comprising immunocompromised patients, but the mechanisms are unknown. These findings support the need for preventive measures against COVID-19 in this vulnerable population and suggest the necessity of proper monitoring and treatment for these patients.

Advancements in the Regulation of Different-Intensity Exercise Interventions on Arterial Endothelial Function.

Normal-functioning endothelium is crucial to maintaining vascular homeostasis and inhibiting the development and progression of cardiovascular diseases such as atherosclerosis. Exercise training has been proven effective in regulating arterial endothelial function, and the effect of this regulation is closely related to exercise intensity and the status of arterial endothelial function. With this review, we investigated the effects of the exercise of different intensity on the function of arterial endothelium and the underlying molecular biological mechanisms. Existing studies indicate that low-intensity exercise improves arterial endothelial function in individuals who manifest endothelial dysfunction relative to those with normal endothelial function. Most moderate-intensity exercise promotes endothelial function in individuals with both normal and impaired arterial endothelial function. Continuous high-intensity exercise can lead to impaired endothelial function, and high-intensity interval exercise can enhance both normal and impaired endothelial function. In addition, it was demonstrated that the production of vasomotor factors, oxidative stress, and inflammatory response is involved in the regulation of arterial endothelial function under different-intensity exercise interventions. We posit that this synthesis will then provide a theoretical basis for choosing the appropriate exercise intensity and optimize the prescription of clinical exercise for persons with normal and impaired endothelium.