Endothelial Impairment Research Articles

Differential effects of heat-not-burn, electronic cigarettes and conventional cigarettes on endothelial glycocalyx

Abstract Background Heat-not-burn cigarette (HNBC) and electronic cigarette (Ecig) constitute non-combustible smoke products. Their effect on endothelial glycocalyx has not been investigated so far. Patients and Methods: Out of 100 subjects attending smoking cessation clinic: α) 50 smokers were randomized to usage of HNBC (n=25) or Ecig (n=25) and β) 50 smokers were used as control group. Participants randomized to the newer tobacco products had similar clinical and demographic characteristics to the control group. Smoking status was verified by measuring the concentration of exhaled carbon monoxide [(e CO) (ppm), Bedfont Scientific, Maidstone, Kent UK]. Perfused Boundary Region (PBR), which is inversely related to endothelial glycocalyx thickness in sublingual arterioles (range 5–25 μm) and blood levels of cotinine, a stable metabolite of nicotine, was assessed in all participants. Exhaled CO, endothelial glycocalyx, and blood cotinine were assessed at baseline and after 1 month. Results Conventional cigarette smokers were aged: 48 ± 5 years, 53% female and used 27 ± 9 cigarettes/day, 29 ± 9 pack-years. HNBC users were aged: 46 ± 14 years, 55% female and used 26 ± 8 cigarettes/day, 30 ± 8 pack-years. Ecig users were aged: 45 ± 8 years, 51% female and used 27 ± 10 cigarettes/day, 28 ± 10 pack-years. Compared to baseline, switching to HNBC for 1 month improved only PBR20-25 (2.55±0.49 vs 2.34±0.34 μm, p=0.002). Ecig use did not alter endothelial glycocalyx in any range of microvessels throughout the study (p>0.05). In contrast, Tcig smoking for one month further worsened endothelial glycocalyx in all microvessels ranges compared to baseline (p<0.05). Blood cotinine levels were similar at baseline and after 1 month using HNBC (p=0.432), Ecig (p=0.535) or conventional cigarette (p=0.489). Compared to baseline, exhaled CO decreased in HNBC or Ecig users (mean percent change: -55% and -58% respectively p<0.001), while remained unchanged in Tcig smokers (p=0.312) at 1 month. Thus, Tcig smokers had higher CO than those who switched to HNBC or E-cig after one month (p<0.01). Conclusion Conventional cigarette users further worsened endothelial glycocalyx after continuing to smoke for one month. In contrast, smokers who switched to Ecig maintained glycocalyx integrity, while those who switched to HNBC showed modest improvement in glycocalyx integrity in microvessels ranging from 20 to 25 μm. Cotinine levels, which reflect nicotine exposure, were similar between the Tcig, HNBC and Ecig groups. Thus, endothelial glycocalyx impairment in the conventional cigarette group was independent of nicotine consumption and possibly related to greater exposure to toxic emissions, such as CO, after Tcig use than after switching to HNBC or Ecig.

Endothelial Unfolded Protein Response-Mediated Cytoskeletal Effects.

The endothelial semipermeable monolayers ensure tissue homeostasis, are subjected to a plethora of stimuli, and their function depends on cytoskeletal integrity and remodeling. The permeability of those membranes can fluctuate to maintain organ homeostasis. In cases of severe injury, inflammation or disease, barrier hyperpermeability can cause irreparable damage of endothelium-dependent issues, and eventually death. Elucidation of the signaling regulating cytoskeletal structure and barrier integrity promotes the development of targeted pharmacotherapies towards disorders related to the impaired endothelium (e.g., acute respiratory distress syndrome, sepsis). Recent reports investigate the role of unfolded protein response in barrier function. Herein we review the cytoskeletal components, the unfolded protein response function; and their interrelations on health and disorder. Moreover, we emphasize on unfolded protein response modulators, since they ameliorate illness related to endothelial leak.

Characterization of microcirculatory endothelial functions in a D-Galactose-induced aging model

BackgroundMicrocirculation health is critical to human health, and aging is an important factor affecting microcirculation health. Although D-Galactose has been widely used in aging research models, there is a lack of relevant studies on D-Galactose simulating microcirculatory aging. Here, we explored microcirculatory endothelial function in D-Galactose-induced aging mice. MethodsIntraperitoneal injection of 150 mg/(kg·d) of D-Galactose was given to cause senescence in mice. Aging was evaluated by SA-β-gal (senescence-associated β-galactosidase) staining. The auricular skin and hepatic microcirculation of mice were observed and detected by enzyme-linked immunosorbent assay (ELISA), immunohistochemistry (IHC) and microcirculation apparatus. The aging of microcirculation was analyzed from oxidative stress, endothelial impairment, inflammation, microvascular morphology and hemodynamics. ResultsIn aging mice, percentage of SA-β-gal positive area, oxidative stress products reactive oxygen species (ROS) and nitric oxide (NO), endothelial impairment marker syndecan-1 (SDC-1), stromal cell derived factor-1 (SDF-1), intercellular cell adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) in the senescence-associated secretory phenotype (SASP) were all up-regulated. The tortuosity of microvessels increased in aging mice, the linear density did not change significantly, but the total length of narrow microvessels (TLNMV) increased and wide microvessels (TLWMV) decreased, speculate that vasomotor dysfunction may be present. Hemodynamically, both perfusion and velocity of blood flow were reduced in senescent mice, presumably due to endothelial dysfunction. ConclusionMicrocirculatory endothelial dysfunction is induced by D-Galactose, leading to microcirculatory aging. In vivo, this is manifested by elevated levels of oxidative stress, impaired endothelial glycocalyx (eGC), and a greater production of chemokines and adhesive molecules. These changes cause vasomotor dysfunction and remodeling, ultimately leading to hemodynamic impairment.

Comprehensive analysis of the m6A demethylase FTO in endothelial dysfunction by MeRIP sequencing

N6-methyladenosine (m6A) is the most general post-transcriptional modification of eukaryotic mRNAs and long-stranded non-coding RNAs. In this process, It has been shown that FTO associates with the m6A mRNA demethylase and plays a role in diabetic vascular endothelial dysfunction. In the present study, we detected FTO protein expression in HUVECs by Western blot and found that FTO was highly expressed in all disease groups relative to the control group. To explore the mechanism of FTO in T2DM vasculopathy, we performed an analysis by methylated RNA immunoprecipitation sequencing (MeRIP-seq) to elucidate the role of aberrant m6A modification and mRNA expression in endothelial dysfunction. The results showed 202 overlapping genes with varying m6A modifications and varied mRNA expression, and GO and KEGG enrichment analysis revealed that these genes were predominantly enriched in pathways associated with T2DM complications and endothelial dysfunction. By an integrated analysis of MeRIP-seq and RNA-seq results, the IGV plots showed elevated kurtosis of downstream candidate gene modifications, which may be downstream targets for FTO to exercise biological functions. HOXA9 and PLAU mRNA expression levels were significantly down after FTO inhibition. In the current work, we set up a typological profile of the m6A genes among HUVECs as well as uncovered a hidden relationship between RNA methylation modifications for T2DM vasculopathy-associated genes. Taken together, this study indicates that endothelial functional impairment is present in T2DM patients and may be related to aberrant expression of FTO.

LDL-c/HDL-c Ratio and NADPH-Oxidase-2-Derived Oxidative Stress as Main Determinants of Microvascular Endothelial Function in Morbidly Obese Subjects.

The identification of obese subjects at higher risk for cardiovascular disease (CVD) is required. We aimed to characterize determinants of endothelial dysfunction, the initial step to CVD, in small omental arteries of visceral fat from obese subjects. The influences of analytical parameters and vascular oxidative stress mediated by NADPH-oxidase-2 (NOX2) on endothelial function were determined. Specimens were obtained from 51 obese subjects undergoing bariatric surgery and 14 non-obese subjects undergoing abdominal surgery. Obese subjects displayed reduced endothelial vasodilation to bradykinin (BK). Endothelial vasodilation (pEC50 for BK) among obese subjects was significantly and negatively associated with low-density lipoprotein cholesterol (LDL-c)/high-density lipoprotein cholesterol (HDL-c) ratio (r = -0.510, p = 0.0001) in both women and men, while other metabolic parameters and comorbidities failed to predict endothelial function. The vascular expression of NOX2 was upregulated in obese subjects and was related to decreased endothelial vasodilation (r = -0.529, p = 0.0006, n = 38) and increased oxidative stress (r = 0.783, p = 0.0044, n = 11) in arterial segments. High LDL-c/HDL-c (>2) and high NOX2 (above median) were independently associated with reduced endothelial function, but the presence of both conditions was related to a further impairment. Concomitant elevated LDL-c/HDL-c ratio and high vascular expression of NOX2 would exacerbate endothelial impairment in obesity and could reveal a deleterious profile for cardiovascular outcomes among obese subjects.

Association between endothelial function and skin advanced glycation end-products (AGEs) accumulation in a sample of predominantly young and healthy adults

BackgroundIn populations with chronic disease, skin autofluorescence (SAF), a measure of long-term fluorescent advanced glycation end-products (AGEs) accumulation in body tissues, has been associated with vascular endothelial function, measured using flow-mediated dilation (FMD). The primary aim of this study was to quantify the relationship between endothelial function and tissue accumulation of AGEs in adults from the general population to determine whether SAF could be used as a marker to predict early impairment of the endothelium.MethodsA cross-sectional study was conducted with 125 participants (median age: 28.5 y, IQR: 24.4–36.0; 54% women). Endothelial function was measured by fasting FMD. Skin AGEs were measured as SAF using an AGE Reader. Participant anthropometry, blood pressure, and blood biomarkers were also measured. Associations were evaluated using multivariable regression analysis and were adjusted for significant covariates.ResultsFMD was inversely correlated with SAF (ρ = -0.50, P < 0.001) and chronological age (ρ = -0.51, P < 0.001). In the multivariable analysis, SAF, chronological age, and male sex were independently associated with reduced FMD (B [95% CI]; -2.60 [-4.40, -0.80]; -0.10 [-0.16, -0.03]; 1.40 [0.14, 2.67], respectively), with the multivariable model adjusted R2 = 0.31, P < 0.001.ConclusionsHigher skin AGE levels, as measured by SAF, were associated with lower FMD values, in a predominantly young, healthy population. Additionally, older age and male participants exhibited significantly lower FMD values, corresponding with compromised endothelial function. These results suggest that SAF, a simple and inexpensive marker, could be used to predict endothelial impairment before the emergence of any structural artery pathophysiology or classic cardiovascular disease risk markers.Trial registrationThe study was prospectively registered with the Australian New Zealand Clinical Trials Registry (ACTRN12621000821897) and concurrently entered into the WHO International Clinical Trials Registry Platform under the same ID number.

Ginsenoside Rh4 prevents endothelial dysfunction as a novel AMPK activator.

The AMP-activated protein kinase (AMPK) signalling pathway is a desirable target for various cardiovascular diseases (CVD), while the involvement of AMPK-mediated specific downstream pathways and effective interventions in hyperlipidaemia-induced endothelial dysfunction remain largely unknown. Herein, we aim to identify an effective AMPK activator and to explore its efficacy and mechanism against endothelial dysfunction. Molecular docking technique was adopted to screen for the potent AMPK activator among 11 most common rare ginsenosides. In vivo, poloxamer 407 (P407) was used to induce acute hyperlipidaemia in C57BL/6J mice. In vitro, palmitic acid (PA) was used to induce lipid toxicity in HAEC cells. We discovered the strongest binding of ginsenoside Rh4 to AMPKα1 and confirmed the action of Rh4 on AMPK activation. Rh4 effectively attenuated hyperlipidaemia-related endothelial injury and oxidative stress both in vivo and in vitro and restored cell viability, mitochondrial membrane potential and mitochondrial oxygen consumption rate in HAEC cells. Mechanistically, Rh4 bound to AMPKα1 and simultaneously up-regulated AKT/eNOS-mediated NO release, promoted PGC-1α-mediated mitochondrial biogenesis and inhibited P38 MAPK/NFκB-mediated inflammatory responses in both P407-treated mice and PA-treated HAEC cells. The AMPK inhibitor Compound C treatment completely abrogated the regulation of Rh4 on the above pathways and weakened the lowering effect of Rh4 on endothelial impairment markers, suggesting that the beneficial effects of Rh4 are AMPK dependent. Rh4 may serve as a novel AMPK activator to protect against hyperlipidaemia-induced endothelial dysfunction, providing new insights into the prevention and treatment of endothelial injury-associated CVD.

Abstract P350: Circulating Endothelial microRNAs in Patients with INOCA and Diabetes Mellitus

Ischemia with no obstructive coronary artery (INOCA) is a common cause of hospitalizations, resulting in poor outcomes and diminished quality of life. A key element in the pathophysiology of INOCA is endothelial dysfunction, which leads to myocardial ischemia despite the absence of significant coronary artery obstruction. Effective management of endothelial dysfunction is essential for alleviating symptoms and preventing cardiovascular events in INOCA patients. Recent studies have highlighted diabetes mellitus (DM) as a significant contributor to INOCA complications by exacerbating endothelial impairment and coronary microvascular dysfunction. MicroRNAs (miRNAs), which are known to regulate gene expression, have emerged as potential biomarkers and therapeutic targets in various biological processes, including endothelial dysfunction and cardiovascular diseases. However, there is a lack of research evaluating miRNA biomarkers specifically in INOCA patients. In our study, we examined a panel of circulating miRNAs associated with the regulation of endothelial function in INOCA patients with and without DM. Using RT-qPCR, we analyzed miRNA expression in a cohort of consecutive patients undergoing percutaneous coronary intervention (PCI) who were confirmed to have INOCA. We measured the expression levels of a previously validated panel of miRNAs in INOCA patients with DM compared to those without DM. Specifically, we observed an increased expression of several miRNAs previously associated with endothelial dysfunction and decreased expression of miRNAs known to protect endothelial function. Further analyses revealed that among these miRNAs, miR-363-5p was significantly downregulated (P&lt;0.001) and miR-92a-3p was significantly upregulated (P&lt;0.001) in INOCA patients with DM compared to those without DM, as illustrated in the volcano plot in Figure 1 . Taken together, our findings demonstrated significant dysregulation of miR-363-5p and miR-92a-3p in INOCA patients with DM compared to those without DM, indicating their potential role as biomarkers for endothelial dysfunction in INOCA.

The Possible Associations between Tauopathies and Atherosclerosis, Diabetes Mellitus, Dyslipidemias, Metabolic Syndrome and Niemann-Pick Disease.

Clinical evaluation and treatment of tauopathic syndromes remain a challenge. There is a growing interest in theories concerning their possible associations with metabolic diseases. The possible connection between those diseases might be linked with cerebrovascular dysfunction. The endothelial cell damage and impairment of the blood-brain barrier observed in atherosclerosis or diabetes may play a role in contributing to tauopathic syndrome development. Additionally, the inflammation evoked by pathological metabolic changes may also be involved in this process. Multiple cases indicate the coexistence of metabolic disorders and tauopathic syndromes. These findings suggest that modifying the evolution of metabolic and cerebrovascular diseases may impact the course of neurodegenerative diseases. Obtained data could indicate the possible benefits of introducing routine carotid artery sonography, revascularization operation or antihypertensive medications among patients at high risk for tauopathies. This review has identified this understudied area, which is currently associated with several diseases for which there is no treatment. Due to the pathomechanisms linking metabolic diseases and tauopathies, further investigation of this area of research, including cohort studies, is recommended and may provide new pharmacological perspectives for treatment.

Exploring the Potential of Saphenous Vein Grafts Ex Vivo: A Model for Intimal Hyperplasia and Re-Endothelialization.

Coronary artery bypass grafting (CABG) utilizing saphenous vein grafts (SVGs) stands as a fundamental approach to surgically treating coronary artery disease. However, the long-term success of CABG is often compromised by the development of intimal hyperplasia (IH) and subsequent graft failure. Understanding the mechanisms underlying this pathophysiology is crucial for improving graft patency and patient outcomes. Objectives: This study aims to explore the potential of an ex vivo model utilizing SVG to investigate IH and re-endothelialization. Methods: A thorough histological examination of 15 surplus SVG procured from CABG procedures at Hospital Canselor Tuanku Muhriz, Malaysia, was conducted to establish their baseline characteristics. Results: SVGs exhibited a mean diameter of 2.65 ± 0.93 mm with pre-existing IH averaging 0.42 ± 0.13 mm in thickness, alongside an observable lack of luminal endothelial cell lining. Analysis of extracellular matrix components, including collagen, elastin, and glycosaminoglycans, at baseline and after 7 days of ex vivo culture revealed no significant changes in collagen but demonstrated increased percentages of elastin and glycosaminoglycans. Despite unsuccessful attempts at re-endothelialization with blood outgrowth endothelial cells, the established ex vivo SVG IH model underscores the multifaceted nature of graft functionality and patency, characterized by IH presence, endothelial impairment, and extracellular matrix alterations post-CABG. Conclusions: The optimized ex vivo IH model provides a valuable platform for delving into the underlying mechanisms of IH formation and re-endothelialization of SVG. Further refinements are warranted, yet this model holds promise for future research aimed at enhancing graft durability and outcomes for CAD patients undergoing CABG.

Methylglyoxal induces endothelial cell apoptosis and coronary microvascular dysfunction through regulating AR-cPLA2 signaling

ObjectiveSince diabetic patients with coronary microvascular dysfunction (CMD) exhibit high cardiac mortality and women have higher prevalence of non-obstructive coronary artery disease than men, we tried to expand the limited understanding about the etiology and the sex difference of diabetic CMD. Approach and resultsAccumulated methylglyoxal (MGO) due to diabetes promotes vascular damage and it was used for mimicking diabetic status. Flow cytometry analysis and isometric tension measurement were performed to evaluate coronary artery endothelial injury. MGO induced apoptosis of coronary endothelial cells, accompanied by downregulation of androgen receptor (AR). Lentivirus-mediated stable expression of AR in coronary endothelial cells increased anti-apoptotic Bcl-2 expression and attenuated MGO-induced cell apoptosis. cPLA2 activation was the downstream of AR downregulation by MGO treatment. Moreover, MGO also activated cPLA2 rapidly to impair endothelium-dependent vasodilation of coronary arteries from mice. Reactive oxygen species (ROS) overproduction was demonstrated to account for MGO-mediated cPLA2 activation and endothelial dysfunction. Importantly, AR blockade increased endothelial ROS production whereas AR activation protected coronary artery endothelial vasodilatory function from the MGO-induced injury. Although galectin-3 upregulation was confirmed by siRNA knockdown in endothelial cells not to participate in MGO-induced endothelial apoptosis, pharmacological inhibitor of galectin-3 further enhanced MGO-triggered ROS generation and coronary artery endothelial impairment. ConclusionsOur data proposed the AR downregulation-ROS overproduction-cPLA2 activation pathway as one of the mechanisms underlying diabetic CMD and postulated a possible reason for the sex difference of CMD-related angina. Meanwhile, MGO-induced galectin-3 activation played a compensatory role against coronary endothelial dysfunction.

Endothelial microRNAs in INOCA patients with diabetes mellitus

Ischemia with non-obstructive coronary artery (INOCA) is a common cause of hospital admissions, leading to negative outcomes and reduced quality of life. Central to its pathophysiology is endothelial dysfunction, which contributes to myocardial ischemia despite the absence of significant coronary artery blockage. Addressing endothelial dysfunction is essential in managing INOCA to alleviate symptoms and prevent cardiovascular events. Recent studies have identified diabetes mellitus (DM) as a significant factor exacerbating INOCA complications by promoting endothelial impairment and coronary microvascular dysfunction. MicroRNAs (miRNAs) have emerged as potential biomarkers and therapeutic targets in various biological processes, including endothelial dysfunction and cardiovascular diseases. However, research on miRNA biomarkers in INOCA patients is sparse. In this study, we examined a panel of circulating miRNAs involved in the regulation of endothelial function in INOCA patients with and without DM. We analyzed miRNA expression using RT-qPCR in a cohort of consecutive INOCA patients undergoing percutaneous coronary intervention. We detected a significant dysregulation of miR-363-5p and miR-92a-3p in INOCA patients with DM compared to those without DM, indicating their role as biomarkers for predicting and monitoring endothelial dysfunction in INOCA patients with DM.

Ultrastructural changes in the adrenal gland in terms of age and gender-related

Objectives: The adrenal glands are endocrine organs that synthesise hormones with crucial functions in the body. This irreplaceable structure performs multiple functions, from metabolism of carbohydrates, fats and proteins to sex development. Any disorder concerning the adrenal glands can give rise to life-threatening conditions. The aging process inevitably affects the adrenal glands. The effects of ageing are marked by a rise in cortisol secretion in the zona fasciculata and a decrease in androgen secretion in the zona reticularis. Elevated cortisol levels in the blood disturb most bodily systems in favour of catabolism, amplifying the cellular decline and destruction that accompanies ageing. The deterioration of the adrenal glands relates not just to spongiocytes and chromaffin cells, but also to the endothelium, which enables circulation. It is clear that a decline in vascular function will have a negative impact on endocrine activities. Our study aims to explore the influence of ageing on the adrenal glands in rats, analysing sex-specific ultrastructural scales. Materials and Methods: A total of 28 Sprague-Dawley rats, 14 males and 14 females, were planned to be used in the study. Of these 28 rats, 4 females and 4 males will constitute the control group. The rats in the control group will be approximately 10 weeks old, and the rats in the experimental group, which will represent the aged group, will be 19 weeks old. All animals in the study will be anaesthetised and then sacrificed by removal of the heart. The right and left common carotid arteries were removed from the sacrificed animals. Collected vessels prepared for TEM examination. For each animal, at least four TEM images were taken from four different sections from the same block. Results: Our findings demonstrate that the ageing process not only affects spongiocytes within the adrenal gland, but also contributes to the deterioration of endothelial cells. As anticipated, our results indicate the presence of senescence and apoptosis in endothelial cells. The observed vascular separations and ruptures are due to the endothelial deterioration. Spongiocytes experienced hypertrophy to compensate for the functional deficiencies following a decrease in their number due to ageing. Elevated levels of lipofuscin, lipid droplets, and lysosomes were discovered in spongiocytes. Impaired endothelium potentially contributes to certain changes in spongiocytes. Conclusions: While ageing-related changes appear similar in both genders, males tend to be more impacted.

Understanding COVID-19 outcome: Exploring the prognostic value of soluble biomarkers indicative of endothelial impairment

Host proteins released by the activated endothelial cells during SARS-CoV-2 infection are implicated to be involved in coagulation and endothelial dysfunction. However, the underlying mechanism that governs the vascular dysfunction and disease severity in COVID-19 remains obscure. The study evaluated the serum levels of Bradykinin, Kallikrein, SERPIN A, and IL-18 in COVID-19 (N-42 with 20 moderate and 22 severe) patients compared to healthy controls (HC: N-10) using ELISA at the day of admission (DOA) and day 7 post-admission. The efficacy of the protein levels in predicting disease severity was further determined using machine learning models. The levels of bradykinins and SERPIN A were higher (P ≤ 0.001) in both severe and moderate cases on day 7 post-admission compared to DOA. All the soluble proteins studied were found to elevated (P ≤ 0.01) in severe compared to moderate in day 7 and were positively correlated (P ≤ 0.001) with D-dimer, a marker for coagulation. ROC analysis identified that SERPIN A, IL-18, and bradykinin could predict the clinical condition of COVID-19 with AUC values of 1, 0.979, and 1, respectively. Among the models trained using univariate model analysis, SERPIN A emerged as a strong prognostic biomarker for COVID-19 disease severity. The serum levels of SERPIN A in conjunction with the coagulation marker D-dimer, serve as a predictive indicator for COVID-19 clinical outcomes. However, studies are required to ascertain the role of these markers in disease virulence.

Mechanisms of vascular inflammaging: TNF-alpha mediates endothelial CEACAM1 expression by NF-KB and beta-Catenin in a biphasic manner

Abstract Funding Acknowledgements Type of funding sources: Foundation. Main funding source(s): German Research Foundation Introduction Chronic inflammation with progressive age, also called inflammaging, is a hallmark of the pathogenesis of cardiovascular diseases. Previously we have shown increased expression of the Carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1) with progressive age in the vasculature of mice and humans that leads to a chronic pro-inflammatory milieu via mutual upregulation with TNF-α. Furthermore, CEACAM1 critically promotes vascular aging processes like collagen deposition, endothelial permeability as well as enhanced oxidative stress. Therefore, CEACAM1 is a main mediator of vascular inflammaging that may facilitate progress into cardiovascular diseases. In this study we identified the mechanisms that underly the upregulation of endothelial CEACAM1 expression by TNF-α in detail. Methods Wildtype (WT) and TNF-α knockout (Tnf-/-) mice of different age were used to determine the impact of TNF-α on age-dependent CEACAM1 expression in vivo. Underlying mechanisms of TNF-α-dependent CEACAM1 upregulation were further analyzed in an endothelial cell culture model using pharmacological inhibition and siRNA-mediated knockdown of signaling pathways. Activation of signaling pathways was confirmed by determining the phosphorylation status of signaling components via Western Blot and analysis of nuclear translocation of NF-κB and β-Catenin using subcellular fractionation. Results Immunohistochemical analyses of aortic sections from WT and Tnf-/- mice of different age reveal that TNF-α critically contributes to the aging-related upregulation of endothelial CEACAM1 expression in vivo. Mechanistic analyses in vitro showed that TNF-α upregulated CEACAM1 expression in a time-dependent manner. In pharmacological experiments we identified an early NF-κB- and a delayed β-Catenin-mediated response. This finding was supported by time-matched nuclear translocation of NF-κB and β-Catenin. Furthermore, siRNA-mediated knockdown of the β-Catenin-targeted transcription factor TCF4 reduced TNF-α-mediated CEACAM1 upregulation. Co-immunoprecipitation analyses show that β-Catenin is released by TNF-α-mediated adherens junctions disassembly. Furthermore, TNF-α enhanced activating phosphorylation of Akt kinase at Ser473. Akt kinase in turn increased phosphorylation of β-Catenin at Ser552, a modification reported to augment its transcriptional activity. Additionally, Akt kinase facilitated β-Catenin signaling by inhibition of its degradation via phosphorylation of GSK3β at Ser9. Conclusion Taken together, this study identified the signaling mechanisms that underly the vascular upregulation of CEACAM1 with age. Our results directly link endothelial barrier impairment, an initial step in the pathogenesis of atherosclerosis, to CEACAM1 expression. Since CEACAM1 critically promotes vascular inflammaging and age-dependent vascular alterations this further emphasizes the potential of CEACAM1 as a novel target to prevent cardiovascular diseases.

Correlation of serum Uric Acid levels with Blood Pressure and Glycated Hemoglobin in Prediabetes and Diabetes patients

Background: Increased serum uric acid (SUA) through a series of pathophysiological sequelae like oxidative strain, inflammation and endothelial vascular impairment causes different diseases. Aim: Evaluate association between serum uric acid levels and hypertension, blood sugar and glycated hemoglobin in prediabetes, diabetes and healthy control. Methods: Cross sectional study conducted in 120 subjects, divided equally into three groups: 40 prediabetes, 40 type 2 Diabetes (T2DM) and 40 healthy controls. Data was collected using a proforma, covering particulars related to hypertension, fasting blood sugar (FBG), glycated hemoglobin (HbA1c) and the levels of SUA. SPSS software was used for analysing the data. Results: The age- and sex-matched prediabetic and diabetic groups had significantly higher systolic and diastolic blood pressures compared to control group. Diabetes markers FBG and HbA1c were recorded highest in the T2DM group, which shows a significant difference in mean compared to prediabetes and the control group. SUA levels were highest in diabetes but found an insignificant difference with prediabetes, whereas the control group showed significant differences (4.4±0.5, p&lt;0.05) with prediabetes (7.1±2.4) and diabetes (7.6±1.5). A significant and positive correlation was recorded between SUA and blood pressure, FBG and HbA1c in the diabetes group. In prediabetes, SUA was found to have a positive association with only systolic blood pressure (SBP) and FBG. Conclusion: Severity of disease progression in patients with hypertension and diabetes, SUA can probably be used as an early biochemical marker. So, assessment of serum uric acid as a routine investigation may be recommended for evaluating disease progress.

Current treatment options for erectile dysfunction in kidney transplant recipients.

Erectile dysfunction (ED) and kidney dysfunction share common risk factors linked to conditions involving endothelial impairment, such as coronary artery disease, dyslipidemia, diabetes mellitus, hypertension, smoking, and obesity. Men with chronic kidney disease experience a high incidence and prevalence of ED. While a functional renal graft can alleviate the issue for some patients, a significant portion of recipients still experience ED (20%-50%). This narrative review describes the variety of current treatments modalities on ED in kidney transplant recipients (KTRs) and their clinical outcomes. MEDLINE, Web of Science, PubMed, and Google Scholar were used to find eligible articles pertaining to the treatment options of ED in KTRs. A total of 64 articles were evaluated. In KTRs, ED stems from a multifaceted etiology: anxiety, drug side effects, interference with penile vascularity, or the response of cavernosal muscle to neurotransmitters, along with changes in the endocrine milieu. A diverse range of treatments to restore erectile function has proven to be safe and effective for KTRs. Options include drug therapy, surgical interventions, intracavernosal injection therapies, vacuum erection devices, and extracorporeal shockwave therapy. The initial treatment approach may involve the use of a phosphodiesterase type 5 inhibitors at a low dosage, especially if testosterone-circulating levels align with the diagnosis of hypogonadism. The consideration of a combination therapy involving testosterone and phosphodiesterase type 5 inhibitors should be contemplated due to the associated beneficial effects. Extracorporeal shockwave therapy has shown positive short-term clinical and physiological effects on erectile function in patients who did not respond to first-line treatments, resulting in spontaneous erections sufficient for sexual penetration in 50% of cases. Penile implants should be considered as third-line options based on specific patient needs and compliance with clinical conditions.

Telomerase Reverse Transcriptase Prevents Doxorubicin-induced Microvascular Endothelial Dysfunction

Introduction &amp; Objective: Doxorubicin (Dox) is a frequently used chemotherapeutic known to induce cardiovascular (CV) complications by impairing microvascular- and cardiac function. We previously submitted an abstract showing that Dox-induced microvascular dysfunction preceded Dox-induced cardiac dysfunction and thus microvascular dysfunction might contribute to the damage of the heart itself.&gt;Microvascular function specifically relies upon the adequate release of the vasodilator nitric oxide (NO). Our previous work showed that Telomerase Reverse Transcriptase (TERT), the catalytic subunit of telomerase, is necessary for physiological release of NO to mediate vasodilation. NO suppresses reactive oxygen species (ROS) levels. While Dox correlates with increased ROS production and suppressed TERT activity, attenuated TERT activity may explain the elevated levels of ROS after Dox exposure. The objective of this study was to determine whether TERT transcriptional activation is suffcient to protect against Dox-induced microvascular endothelial- and cardiac dysfunction. We utilized cycloastragenol (CAG) as transcriptional activator. Hypothesis: We hypothesized that TERT transcriptional activation is suffcient to prevent or attenuate Dox-induced endothelial dysfunction. Methods: WT or TERT loss-of-function rats on a Sprague Dawley background were assigned to untreated control-, CAG-, Dox and CAG+Dox groups. Animals were ~14 weeks of age to start the six-week protocol. Dox and CAG+Dox animals received one weekly IP Dox-injection (3x 4mg/kg*BW). CAG administer via diet with 50-60mg of CAG/day*BW. Microvascular function was assessed six-weeks after the first dose of Dox via videomicroscopy. Vasodilator responses to flow (flow-mediated dilation; FMD) and mediators of dilation (NO, H2O2) via fluorescent probes were evaluated. Cardiac function was evaluated using echocardiography. Human microvessels were treated either with 100nM Dox or 1μM CAG or a combination of both. Results: Dox treatment resulted in reduction in FMD in both WT and TERT mutant animals. Smooth-muscle dependent vasodilation was not impaired indicating endothelial impairment. CAG prevented Dox-induced endothelial dysfunction in WT but not TERT mutant rats. AGS499 another activator of TERT showed similar results suggestion a TERT mediated phenotype. Dox-treated WT animals exhibited an increase in H2O2 but not NO production. This phenotype was opposite in CAG+Dox WT animals. TERT mutant animals showed an increase in H2O2 but not NO production even without Dox. To assess which vasodilator mediates dilation to flow, we used L-NAME and PEG-Catalase to block NO- and H2O2, respectively. In CAG+Dox WT animals, L-NAME blocked the vasodilatory response to flow, while PEG-Cat blocked the vasodilatory response non-significantly. Similarly, we observed this protective effect of TERT in the human microcirculation. Human adipose microvessels treated over-night with Dox showed no vasodilatory response to flow while CAG+Dox treated vessels dilated normally similar to untreated control vessels. Smooth muscle function was not affected in neither group. Conclusion: We show evidence that TERT prevents Dox-induced endothelial dysfunction in an in vivo model and using human tissue. We highlight the specificity to TERT by a) using a genetic model lacking normal TERT activity and b) showing similar results using two different compounds which have been shown to activate TERT/promote TERT transcriptional activation. Ultimately, the present data shows that CAG is a potential therapeutic to counteract the detrimental effects of Dox treatment in the CV system via TERT signaling. RO1 HL133029-01. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Can the dietary inorganic nitrate supplementation mitigate the vascular dysfunction in elderly with Alzheimer’s disease?

Aging and Alzheimer disease (AD) are both characterized by progressive reduction in nitric oxide bioavailability and endothelial function impairment. Promising studies on young healthy individuals underly the positive effect of dietary nitrate supplementation on endothelial function. However, the pharmacokinetics of the plasma nitrate and nitrite (PN) and the accompanying endothelial responsiveness following the oral nitrate ingestion in healthy elderly (HE) and patients with AD is not clear. Our hypothesis was that due to the reduction of nitric oxide bioavailability during aging and AD, an equal dose of oral nitrate (ON) would ameliorate the endothelial responsiveness more in the HE and even more in patients with AD in comparison to healthy young subjects (HY). Therefore, with the aim of investigating the pharmacokinetics of PN and the time-course endothelial responsiveness in response to a single dose ON, 10 HY (25±4 YRS), 10 HE (72±8 YRS) and 13 AD (73±7 YRS) were recruited. PN levels and endothelial responsiveness (single-passive leg movement (ΔPLM)) were measured in the recruited individuals prior to (T0) and hourly for 4 hours (T1, T2, T3, and T4) after: a) a single dose of ON; and b) a single dose of placebo. As expected at T0 both PN and ΔPLM were significantly reduced in the HE and even more reduced in the AD in comparison to the HY (all p&lt;0.001). No changes in PN nor ΔPLM were detected in any group following placebo intake. PN increased significantly in all three groups at T1 (p&lt;0.001) and constantly increased up to T4, but no differences were detected between time points T1 to T4 in any group. ΔPLM increased significantly in all three groups at T2, reaching highest values at T4 (p&lt;0.001). However, AD exhibited significantly lower ΔPLM values at any time point compared to HY (p&lt;0.0001) and HE (p&lt;0.001). Significant correlation between PN and ΔPLM was found (p&lt;0.001, R2=0.1654). Contrary to our hypothesis, the results of this study suggest that the PN pharmacokinetics following a single dose of ON is similar in HY, HE and AD. Moreover, the expected time-course amelioration of the endothelial responsiveness was reduced in the HE and even more reduced in the AD, suggesting that other factors, rather than the nitric oxide bioavailability, are playing a role in the age- and AD-related vascular dysfunction. Ricerca di Base 2017 - RBVR17XRSA - Effectiveness of exercise and nitrate supplementation on progression of dementia in patients with Alzheimer’s disease. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Endothelial function cannot be assessed by the reactive hyperemia following occlusion

Reactive hyperemia (RH) and the post occlusive reactive hyperemia (PORH) are known to assess vascular function in vivo and referred as useful prognostic tools in vascular medicine. However, its translation to clinical practice is poor due to important unsolved inconsistencies. Our group has been studying the adaptive responses following RH. Here we clarify the involved mechanism, its impact on general hemodynamics and the significance of these responses. A convenience sample of fourteen healthy women (48.0 ± 8.0 y.o.) was selected, all being normotensive non-menopausal, with no signs of vascular impairment (normal ankle-brachial index and mean arterial pressure MAP), and with (self-reported) equivalent levels of physical activity. The study followed all principles of good clinical practice established for human research and was previously approved by the institutional Ethics Committee. The protocol included three phases—a baseline register (Phase I) during rest, giving place to the occlusion as part of the PORH maneuver challenge period (Phase II) with one minute, followed by a ten-minute recovery period (Phase III). PORH was performed on one randomly chosen upper limb, using the cuff of the TASK FORCE® platform for the continuous monitoring of blood pressure and hemodynamics. After baseline acquisition, the cuff was rapidly inflated with 200 mmHg to occlude the brachial artery for one minute. Then the cuff was rapidly deflated, and signals registered for recovery recordings. Perfusion was measured in both hands by laser Doppler flowmetry (3rd finger) with a Perimed5000 system. To confirm previous evidence regarding the mechanism(s) involved, we also accessed the RH impact(s) on the contralateral forearm skin circulation by functional imaging using a multi-scan photoptoacoustic tomography (PAT) (MSOT iThera system). The tissue hypoxia related to RH-PORH is referred to evoke a local vasodilation, such that hyperemia occurs following the cessation of occlusion. Thus, any reduction of this response has been associated to endothelial impairment. However, our studies have shown suffcient evidence of a centrally mediated reflex rather than a local response mediated by local vasodilators. In fact, LDF clearly detected significant perfusion reductions in both hands during and following occlusion, more pronounced in the challenged limb, while PAT confirmed similar changes in the superficial plexus on the contralateral forearm. Additionally of interest, no significant hemodynamical changes were found with PORH apart from MAP when comparing recovery with baseline periods. Our results clearly show that the physiological significance of RH or POHR reduction can no longer be regarded to solely represent “endothelial disfunction” but rather an expression of a global adaptive hemodynamical response, centrally mediated, that might originate essential endpoints also measurable in the contralateral limb, with clinical utility. This research was financed by national funds through FCT - Foundation for Science and Technology, I.P. (Portugal), under the [UIDB/04567/2020] and [UIDP/ 04567/2020] projects, and by COFAC/ALIES for the use of the photoacoustic instrument. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.