Vascular Endothelial Function Research Articles

ARGININE METABOLISM AND ARTERIAL STIFFNESS IN HIGHLANDERS WITH HIGH ALTITUDE POLYCYTHEMIA

Objective: High altitude polycythemia (HAPC) is a health condition associated with hypoxemia and erythrocytosis. Patients with chronic hypoxemia often exhibit arterial stiffness. In the advanced stages of HAPC, patients can present changes in the pulmonary circulation, but limited information exists regarding arterial stiffness. Our study aims to investigate the relationship between HAPC and arterial stiffness, and explore the underlying mechanisms. Design and method: At an altitude of 3500m, we conducted a study examining arterial stiffness and vascular endothelial function in two groups of hypertensive highlanders with and without HAPC, each consisting of 30 participants. Plasma samples were measured using Ultra Performance Liquid Chromatography Tandem Mass Spectroscopy. Results: Hypertensive highlanders with HAPC exhibited notable vascular dysfunction, as indicated by significantly impaired flow-mediated dilation (FMD) (3.97±1.21% vs. 6.82±1.46%, P < 0.001), and higher brachial-ankle pulse wave velocity (BaPWV) (1556±239 cm/s vs. 1890±459 cm/s, P < 0.001). Metabolomics analysis revealed alterations in arginine/proline metabolism and the arginine biosynthesis pathway, involving L-arginine, L-ornithine, creatine and 4-guanidinobutanoic acid. The area under the curve (AUC) values for 4 metabolites and L-arginine/L-ornithine ratio were 0.753, 0.782, 0.720, 0.717 and 0.819, respectively. Pearson correlation analysis showed that L-arginine, L-ornithine, and L-arginine/L-ornithine ratio were associated with BaPWV (r=-0.4486, P=0.00032; r=0.3400, P=0.0078; r=0.3921, P=0.0019). L-arginine, L-ornithine, 4-guanidinobutanoic acid, creatine, and L-arginine/L-ornithine ratio were correlated with FMD. Multiple linear regression analysis revealed that L-arginine and L-arginine/L-ornithine ratio were independently correlated with BaPWV (beta= -0.370, t=-3.114, P=0.003; beta=-0.268, t=-2.211, P=0.032) and FMD (beta=0.434, t=3.114, P=0.003; beta= 0.457, t=3.445, P=0.001), but L-ornithine was not independently related to BaPWV and FMD. Conclusions: Our study indicates that HAPC may accelerate the progression of arterial stiffness in hypertensive patients. In fact, L-arginine takes an important role in the forming of NO in vascular endothelium. So The disorder of arginine metabolism may serve as the underlying metabolic mechanism.

Abstract 130: Cftr Is Essential For Endothelium-dependent Vasorelaxation

Genetic mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene lead to cystic fibrosis (CF) which causes multiple health issues including lung disease and diabetes. Importantly, along with other health conditions, CF patients are long known to have impaired vascular function. Specifically, endothelium-dependent vasorelaxation is impaired in people with CF. However, the molecular mechanism(s) involved in the impairment of endothelial function in CF is not known. Since impaired endothelial function is an established risk factor for cardiovascular diseases, we investigated how CFTR regulates vascular endothelial function. We evaluated coronary arteries of CFTR -/- and littermate wild type piglets and noted profound endothelial dysfunction in coronary arteries of CFTR -/- piglets (n=10-12 rings/3 piglets). Next, we generated a mouse model with endothelium-specific deletion of CFTR (e-CFTR -/- ). Aortic rings of e-CFTR -/- mice showed a significant delay in endothelium-dependent vasorelaxation (P<0.001; n=20 rings /5 mice). To determine the molecular signaling mediating this effect, we used a pharmacological inhibitor of CFTR (CFTRinh-172) and examined changes in endothelial nitric oxide synthase (eNOS). CFTRinh-172 treatment (10 μM, 5 days) led to a significant reduction in total and S1177 phosphorylated level of eNOS in human coronary artery endothelial cells (P<0.01 and P<0.05; n=3). In addition, CFTRinh-172 treated endothelial cells exhibited increased inflammation and altered endothelial cell metabolism (n=6; P<0.001). Together, these findings suggest that CFTR regulates eNOS and cellular metabolism in endothelial cells and therefore, functional CFTR is essential for vascular endothelial function. This fundamental role of CFTR in endothelial function will have future translational value in treating people with CF.

ER stress CHOP Knockout in Beta Cells protects from type 2 diabetes-induced vascular dysfunction

Introduction: Cardiovascular complications are the primary causes of morbidity and mortality in patients with type 2 diabetes (T2D). T2D is a significant risk factor for cardiovascular diseases such as coronary artery disease, stroke, peripheral vascular disease, and heart failure for millions of people in the US. In the present study, we determined the role of the endoplasmic reticulum stress (ER) stress C/EBP homologous protein (CHOP) in beta cells on type 2 diabetes-induced vascular endothelial dysfunction. Methods: male and female CHOPflox/flox and CHOPbeta cells −/− mice were fed a high-fat diet (HFD) for 12 weeks. We measured body weight, running distance, heart/lung/pancreas/kidney weights, glucose tolerance test (GTT), vascular endothelial function, and signaling. Results: Our research indicates that mice with the ER stress CHOPflox/flox genotype, when fed a high-fat diet for 12 weeks, develop obesity and show impaired GTT and running distance. Additionally, they exhibit an increase in the weight of organs such as the heart, lungs, pancreas, and kidneys and experience vascular endothelial dysfunction and a reduction in phosphorylated eNOS levels. However, it's interesting to note that mice that lack the ER stress CHOPbeta cells−/− and were fed the same high-fat diet for 12 weeks displayed a protective effect. Conclusion: The data indicates that beta cell ER stress CHOP plays an essential role in type 2 diabetes. Disrupting the ER stress CHOP, specifically in beta cells, has been shown to protect mice from the vascular endothelial dysfunction caused by type 2 diabetes. Therefore, targeting ER stress CHOP, specifically in beta cells, could be a promising therapeutic approach to safeguard vascular endothelial function. NIH-HL150014 (Matrougui) and NIH-HL151616 (Matrougui). 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.

Cell-Free Hemoglobin Induces Vascular and Mitochondrial Dysfunction in the Pulmonary Endothelium in an Oxidation-State Dependent Manner

Background: Sepsis results in significant organ damage due in part to a breakdown in endothelial vascular function. Elevated levels of cell-free hemoglobin (CFH) drive endothelial dysfunction in the lungs. CFH generates reactive oxygen species (ROS) via the iron present in the heme moiety, which can be oxidized from ferrous (CFH2+) to ferric (CFH3+). Recent studies suggest mitochondrial dysfunction may be a key pathway leading to microvascular dysfunction. We hypothesize that CFH induces mitochondrial dysfunction and microvascular endothelial barrier disruption in the lung in an oxidative-state dependent manner. Methods: CFH was converted from CFH2+ to CFH3+ by UV irradiation (validated by spectrophotometry). Primary human lung microvascular endothelial cells (HLMVECs) were treated with 1.0 mg/mL CFH2+, CFH3+, or vehicle control. Barrier dysfunction was measured via electric cell-substrate impedance sensing (ECIS) and express permeability test (XPerT) at 24h. We quantified mitochondrial superoxide (MitoSOX Red; 5 uM) by flow cytometry (1, 6, 24h) and total cellular ROS production (CellROX Deep Red; 5 uM) by fluorescence microscopy (6 and 24 h). Mitochondrial morphology (electron density, roundness, area, circularity, and aspect ratio) was assessed by transmission electron micrographs at 6h and quantified by a blinded reviewer (ImageJ). Activation of the mitochondrial permeability transition pore (mPTP) was assessed by flow cytometry using calcein-AM with cobalt chloride. DNA was purified from patient plasma and the copy number of mitochondrial genes ND4L and CYB was quantified by digital droplet PCR. Results: In HLMVECs, CFH generated excess ROS (CellROX and MitoSOX) at 6h compared to vehicle (522 vs 265 MFI, p < 0.01). Morphology analysis demonstrated increased electron density and aspect ratio and decreased circularity and roundness. mPTP activity was increased by CFH3+ (1295 vs 2197 MFI, p < 0.01) compared to vehicle or CFH2+. Barrier dysfunction caused by CFH3+ measured by ECIS peaked at 6h (-1270 vs 262 max TER drop, p < 0.0001), while XPerT confirmed dysfunction at 24h (9.41e+06 vs 6.53e+05 total fluorescent area, p < 0.01). Quantification of mtDNA copy number in patient plasma revealed that circulating mt-ND4L copies correlate with CFH (r = 0.44, p < 0.01). Conclusions: The results demonstrate significant perturbations to mitochondrial function and network dynamics caused by oxidized CFH (3+). The novel findings point towards the ferric (3+) form of hemoglobin as the primary driver of endothelial dysfunction, and the underlying mechanism is directly related to disruption of the mitochondrial network. The association of mitochondrial and vascular biomarkers demonstrates an urgent need to better understand how mitochondrial dysfunction can be prevented to limit vascular damage. This work was funded by the National Institutes of Health NHLBI 5R35HL150783 and 1F31HL167471. 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.

Small Molecule Drug C381 Attenuates Brain Vascular Damage Following Repetitive Mild Traumatic Injury.

Traumatic brain injury (TBI) remains a significant public health concern, with no effective therapeutic interventions to ameliorate the enduring consequences. The prevailing understanding of TBI pathophysiology indicates a central role for vascular dysfunction. Transforming growth factor-β (TGF-β) is a multifunctional cytokine crucial for vascular development. Aberrant TGF-β signaling is implicated in vascular pathologies associated with various neurological conditions. We recently developed a novel small molecule drug, C381, a TGF-β activator with the ability to restore lysosomal function. Here we used a mouse model of repetitive mild TBI (mTBI) to examine whether C381 would attenuate vascular injury. We first employed RNA-seq analysis to investigate the gene expression patterns associated with mTBI and evaluated the therapeutic potential of C381 in mitigating these changes. Our results demonstrate distinct mTBI-related gene expression signatures, prominently implicating pathways related to vascular integrity and endothelial function. Notably, treatment with C381 reversed these mTBI-induced gene expression changes. Immunohistochemical analysis further corroborated these findings, revealing that C381 treatment attenuated vascular damage in mTBI-affected brain tissue. These findings strongly support the potential clinical usefulness of C381 as a novel therapeutic intervention for mTBI.

Proteomic Analysis of Prehypertensive and Hypertensive Patients: A Novel Role of Actin Cytoskeleton in Disease Progression

Background: Hypertension is a pervasive and widespread health condition that poses a significant risk factor for cardiovascular disease, which includes conditions such as heart attack, stroke, and heart failure. Despite its widespread occurrence, the exact cause of hypertension remains unknown, and the mechanisms underlying the progression from prehypertension to hypertension require further investigation. Methods: To uncover potential biomarkers related to disease development, proteomic profiling using SOMAscan proteomic platform was conducted on Qatari individuals with prehypertension and hypertension. In this study, proteomic data collected from the Qatar Biobank were analyzed to compare participants with prehypertension, hypertension, and normal blood pressure. Statistical analysis was performed to identify altered protein expression between the study groups and to elucidate the biological pathways contributing to this disease. Results: The results revealed a cluster of proteins, including the SRC family, CAMK2B and CAMK2D, TEC, GSK3, VAV, and RAC, that were markedly upregulated in patients with hypertension compared to those with prehypertension (fold change ≥ 1.6 or ≤ -1.6, area under the curve ≥ 0.8, and q-value < 0.05). Pathway analysis showed that the majority of these proteins play a role in actin cytoskeleton remodeling, a crucial pathological event involved in hypertension progression. Conclusion: Actin cytoskeleton reorganization affects various biological processes that contribute to the maintenance of blood pressure, including vascular tone, endothelial function, cellular signaling, inflammation, fibrosis, and mechanosensing. Therefore, the findings of this study suggest a potential novel role of actin cytoskeleton-related proteins in the progression from prehypertension to hypertension. The present study sheds light on the underlying pathological mechanisms involved in hypertension and could pave the way for new diagnostic and therapeutic approaches for the treatment of this disease. This study was made possible through the support of Qatar University. 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 PPARD regulates nutrient transport and exercise endurance in mice

Vascular endothelial cell function is important for regulating vascular perfusion, which is increased in the skeletal muscle during exercise. Our previous research identified endothelial selective PPARD, a transcription factor, which is critical for endothelial cell function and homeostasis. Loss of PPARD in endothelium enhances vascular inflammation and disrupts endothelial integrity. In the present study, we aims to investigate whether endothelial PPARD is involved in nutrient transport in the muscle endothelial cells and whether it is involved in exercise endurance and training effcacy. The Cdh5-Cre driven deletion of the floxed Ppard allele was used for making the endothelium selective Ppard knockout (PpardEC-KO) mice and wild type littermates (PpardEC-WT). Human endothelial cells were used to examine glucose and fatty acid uptake and its transport to myocytes. Treadmill exercise with incremental speed and inclination was used. Both PpardEC-WT and PpardEC-KO mice were viable and did not show abnormalities at baseline. Both PpardEC-WT and PpardEC-KO mice were put on treadmill to test their running endurance. Deletion of Ppard in endothelium resulted in early exhaustion, shortened distance, and less speed. Running exercise for 4 weeks partially improved endurance in the PpardEC-KO mice. PpardEC-KO mice had less oxidative muscle fibers both at baseline and after training. Higher blood lactate level and less glucose preservation were found in PpardEC-KO mice after running the same distance as PpardEC-WT mice. In human endothelial cells, PPARD knockdown resulted in less glucose and fatty acid uptake. Glucose transport to myocyte from endothelial cells was also attenuated with PPARD knockdown. PPARD may act through SGK1 responsible for GLUT1 expression and glucose uptake. Our study showed an important role of endothelial cell in regulating nutrient transport into skeletal muscle during physical exercise. Impaired endothelial transport of glucose and fatty acid reduces exercise endurance. This study is funded by the General Research Funds 14107822 and 14105321 from the Hong Kong University Grant Council. 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.

The Relationship of Mitral Annular Calcification and Aortic Valve Sclerosis to Endothelial Dysfunction.

Calcific aortic valve disease (CAVD) and mitral annular calcification (MAC) are associated with various cardiovascular diseases and may influence systemic vascular pathologies. However, their relationship with endothelial dysfunction and carotid intima-media thickness (CIMT) remains poorly elucidated. This research aims to explore the associations between MAC, aortic valve sclerosis (AVS), and markers of vascular dysfunction, specifically CIMT and endothelial function. This prospective observational study included 200 patients undergoing routine echocardiographic evaluation at the National Heart Institute between May 2022 and April 2023. Patients were stratified into four groups namely isolated MAC (38 patients), isolated AVS (72 patients), combined MAC and AVS (50 patients), and a control group without MAC or AVS (40 patients). All participants underwent comprehensive cardiovascular evaluation, including transthoracic echocardiography (TTE) and carotid duplex ultrasonography. Endothelial function was determined by measuring reactive hyperemia-induced alterations in brachial artery diameter. The mean age of participants was 60.6±8.4 years, with a predominance of male subjects (64%). No significant differences were noted in baseline demographic and clinical characteristics across the groups. Patients with isolated AVS, isolated MAC, and both conditions demonstrated increased CIMT compared to controls, with significant differences noted in the combined MAC and AVS group compared to controls (p-value=0.031). Endothelial dysfunction was observed in 14.8% of the AVS group and 21.1% in the combined group, but no significant differences existed when compared to controls. The study also revealed that patients with AVS are more likely to exhibit increased CIMT (p-value=0.008). Both MAC and AVS are connected to increased CIMT, suggesting a link with systemic atherosclerotic processes. Although the existence of endothelial dysfunction was not significantly higher in patients with valvular calcifications, the findings support the need for further research into the cardiovascular implications of CAVD and MAC.

Does Chronotype Influence Diurnal Changes in Cardiovascular Disease Risk Factors? A Preliminary Analysis

Introduction: Humans experience diurnal fluctuations in the prevalence of cardiovascular events which is likely an output of endogenous circadian influence. Relatedly, vascular endothelial cell function, measured by conduit artery responsiveness to hyperemia during a flow-mediated dilation test, is supposed to follow a diurnal rhythm that is moderated by an individual’s chronotype. We therefore sought to examine the extent to which diurnal changes in other cardiovascular risk factors, such as blood pressure, cardiac chronotropy, and circulating blood leukocytes, were related to chronotype in humans. A moderating influence of chronotype on diurnal changes in the aforementioned parameters was hypothesized given prior research associating a preference for evening wakefulness with an adverse cardiometabolic phenotype. Methods: All data are presented as mean ± standard deviation. This abstract includes secondary data from a preliminary sample of 16 young (19 ± 2 years), healthy males and females. Participants completed a Munich Chronotype Questionnaire (MCQ) to quantify diurnal preference for morning or evening activity. The corrected mid-sleep time on free days (MSFSC) was calculated from the MCQ and interpreted to represent an index for morning or evening chronotype. Participants attended data collection sessions in the morning (09:16 ± 01:27 hh:mm) and again in the evening (16:19 ± 00:31 hh:mm) under resting conditions for the quantification of blood pressure and enumeration of circulating leukocytes from venous blood. Results: The sample included in this analysis had a slight preference for evening wakefulness (MSFSC = 04:58 ± 01:17 hh:mm). A significant and robust diurnal variation was found among circulating venous leukocytes (P < 0.001) which measured higher in the afternoon (2.06×106 ± 3.67×105 cells/mL blood) than morning (1.61×106 ± 4.68×105 cells/mL blood). The diurnal variation in circulating venous leukocytes was independent (β = -9.87×104; R2 = 0.19; P = 0.186) of individual chronotype, as were individual diurnal changes of all other hemodynamic parameters included in this analysis (all P > 0.05). More participants will be recruited to satisfy statistical power for primary outcomes. Discussion: These preliminary results from healthy, young adults indicate that individual disposition towards morning or evening wakefulness may not exert a profound influence over diurnal changes in several cardiovascular disease risk factors under resting conditions. Funding Sources: The study was funded by the Natural Sciences and Engineering Research Council of Canada (DG: 20011033) held by Dr. MJM). JMC and MIB were supported by Ontario Graduate Scholarships. JCS was supported by the Natural Sciences and Engineering Research Council of Canada Graduate Scholarships – Master’s. 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.

ZFYVE21 promotes endothelial nitric oxide signaling and vascular barrier function in the kidney during aging

ZFYVE21 is an ancient, endosome-associated protein that is highly expressed in endothelial cells (ECs) but whose function(s) invivo are undefined. Here, we identified ZFYVE21 as an essential regulator of vascular barrier function in the aging kidney. ZFYVE21 levels significantly decline in ECs in aged human and mouse kidneys. To investigate attendant effects, we generated EC-specific Zfyve21-/- reporter mice. These knockout mice developed accelerated aging phenotypes including reduced endothelial nitric oxide (ENOS) activity, failure to thrive, and kidney insufficiency. Kidneys from Zfyve21 EC-/- mice showed interstitial edema and glomerular EC injury. ZFYVE21-mediated phenotypes were not programmed developmentally as loss of ZFYVE21 in ECs during adulthood phenocopied its loss prenatally, and a nitric oxide donor normalized kidney function in adult hosts. Using live cell imaging and human kidney organ cultures, we found that in a GTPase Rab5- and protein kinase Akt-dependent manner, ZFYVE21 reduced vesicular levels of inhibitory caveolin-1 and promoted transfer of Golgi-derived ENOS to a perinuclear Rab5+ vesicular population to functionally sustain ENOS activity. Thus, our work defines a ZFYVE21- mediated trafficking mechanism sustaining ENOS activity and demonstrates the relevance of this pathway for maintaining kidney function with aging.

Inspiratory Muscle Strength Training to Improve Cardiometabolic Health in Patients with Type 2 Diabetes Mellitus

Type 2 diabetes mellitus (T2DM) is a complex, chronic metabolic disease that is associated with a high prevalence of comorbid conditions. Traditional lifestyle interventions (e.g., diet and exercise) can counter some adverse effects of T2DM; however, participation in these activities is low. High-resistance inspiratory muscle strength training (IMST) is a time-effcient and simple breathing exercise that significantly reduces blood pressure (BP) and improves vascular endothelial function in several nondiabetic populations. Herein, we performed a blinded, randomized, sham-controlled trial to investigate the effects of a 6-week IMST regimen (30 breaths/day, 6 days/week) on glycemic control and insulin sensitivity in adults with T2DM. Currently, we have eight participants (aged 35-71 years, 5 females and 3 males) who have completed either low-resistance sham training (15% maximal inspiratory mouth pressure, n=5) or high-resistance IMST (75% maximal inspiratory mouth pressure, n=3). Our data suggests that fasting plasma glucose and fasting serum insulin did not significantly change by IMST or sham training. Utilizing a homeostatic model assessment of insulin sensitivity to evaluate insulin action, our results indicate no change by either IMST or sham training. IMST revealed a trend towards a reduction in systolic BP (pre: 133.0 ± 4.8 vs. post: 128.8 ± 4.9) and diastolic BP (pre: 84.8 ± 2.7 vs. post: 81.7 ± 3.6). These findings align with prior research indicating improved resting BP, further corroborating previous studies. We performed an exploratory analysis to examine the potential impact of IMST on lipid levels. Interestingly, IMST resulted in a trend towards a reduction in cholesterol (pre: 259.3 ± 29.4 vs. post: 230.3 ± 3.7) and LDL (pre: 153.3 ± 19.7 vs. post: 127.7 ± 8.7). Analysis of the endothelial function data is forthcoming until we have enough individuals to complete those analyses. In conclusion, our results to date are preliminary; however, we expect to see continued improvements in resting BP and cholesterol/LDL with IMST. Moreover, with a higher number of individuals in the study (our goal is to have 12 in each group), we anticipate seeing changes in glycemia or insulin action. Lastly, IMST stands out as a distinctive and time-effective exercise method, addressing adherence challenges while demonstrating enhancements in cardiometabolic health. This could be particularly advantageous for T2DM patients with an increased cardiovascular disease risk. University of Arizona College of Medicine SPARK Grant. 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.

INTRAVENOUS IMMUNOGLOBULINS LEAD TO FUNCTIONAL VASCULAR AMELIORATION IN LONG-COVID

Objective: The Long-COVID syndrome constitutes a major physical and psychological challenge for many patients after the recovery from COVID-19. We have previously shown positive effects of intravenous immunoglobulins (IVIG) on multiple symptoms. The effect of this therapeutical approach on vascular function and different levels of disease burden remains elusive. Design and method: We performed a prospective study, enrolling 21 patients with diagnosed Long-COVID, who received 3 monthly courses of IVIG (0.5 g/kg Privigen, CSL Behring, Austria) alongside supportive therapy (group 1). The control group (group 2; n=29) was addressed by supportive therapy, only. The study population was homogeneous for age, comorbidities and time since SARS-CoV-2 infection. We assessed vascular endothelial function by flow mediated dilation (FMD). Long-COVID associated fatigue intensity, related disability and quality of life were assessed by Short Form Health Survey-36, Chalder and Bell scale. Neuropsychological assessments utilized the German version of the ’Consortium to Establish a Registry for Alzheimer's Disease Neuropsychological Assessment Battery’ (CERAD-Plus). Results: The median FMD at baseline in group 1 was 5.0% (interquartile range [IQR] 4.2-6.1%). We saw a substantial amelioration (+27%) of FMD after IVIG, reaching a median of 6.6% (IQR 4.5-9.4%; p=0.039). Baseline FMD in the comparison group was 5.2% (IQR 3.5-7.6%), supportive treatment resulting in unsignificant increase (FMD 6.1% [IQR 4.6-7.7%; p=0.177). Baseline CERAD-Plus scores were comparable between groups (p=0.280). Only treatment with IVIG resulted in a relevant amelioration of neurocognition (p=0.05; group 2 p=0.430). Furthermore, less Fatigue (Chalder Fatigue scale bimodal and Likert p=0.002, each) and disability was seen after 3 months of IVIG (Bell Score, p=0.008), supportive treatment did not ameliorate this burden (Chalder Fatigue Scale bimodal p=0.086 and Likert p=0.952; Bell Score p=0.121). Health related quality of life (SF-36) increased for both groups (group 1 p=0.003, group 2 p=0.017). Conclusions: Using a broad test battery, addressing neuropsychological function, fatigue, related disability and health related quality of life as well as vascular function, we were able to confirm the potential beneficial effect of IVIG in Long-COVID. IVIG might be a candidate approach in this context, that requires further evaluation in randomized controlled trials.

Nitrate-rich beetroot juice supplementation in midlife and older adults with renal dysfunction increases vascular endothelial function and changes the circulating milieu to improve endothelial cell nitric oxide production and oxidative stress

BACKGROUND: Midlife and older (ML/O) adults with mild-to-moderate renal dysfunction (MRD) are at increased risk for cardiovascular disease (CVD). A key antecedent to CVD in ML/O adults with MRD is vascular endothelial dysfunction, mediated by declines in nitric oxide (NO) bioavailability due to excess reactive oxygen species (ROS)-related oxidative stress. We have shown that targeting the nitrate-nitrite-NO pathway with sodium nitrite in heathy ML/O adults improves endothelial function and changes the circulating milieu to lower endothelial cell (EC) ROS bioactivity. However, if nitrate-rich beetroot juice (N-BRJ) is effective for improving endothelial function in ML/O men and women with MRD is unknown. HYPOTHESES: We tested the hypotheses that chronic N-BRJ in ML/O men and women with MRD would: 1) improve endothelial function and 2) induce changes to the circulating milieu to increase EC NO production and lower EC ROS bioactivity. We also assessed possible sex differences in the effcacy of N-BRJ for improving endothelial function. METHODS: Twenty-six ML/O men and women with MRD (estimated glomerular filtration rate [eGFR; CKD-EPI]: 40-89 mL/min/1.73m2) underwent three months of supplementation with N-BRJ (70 mL with 6.45 mmol nitrate/day) (n=13, 7 women; age: 65±2 years; eGFR: 69.2±3.3 mL/min/1.73m2) or nitrate-depleted BRJ (placebo, PBO) (n=13, 7 women; age: 68±2 years; eGFR: 79.8±3.1 mL/min/1.73m2) in a randomized, placebo-controlled, parallel-group design clinical trial. Endothelial function was assessed by brachial artery flow-mediated dilation (FMDBA). Smooth muscle sensitivity to NO was assessed by brachial artery dilation to sublingual nitroglycerin. Human aortic ECs (HAECs) in culture were exposed to 10% subject serum (n=10[6-7 women]/group) collected before and after N-BRJ and PBO supplementation. Acetylcholine-stimulated NO production (DAR-4M-AM) and whole-cell ROS bioactivity (CellROX) were assessed in HAECs using immunofluorescence. Results: N-BRJ supplementation increased FMDBA by 28% (pre: 4.6±0.7%, post: 5.9±0.8%; p=0.03). FMDBA did not change with PBO (pre: 4.6±0.9%, post: 4.7±0.8%; p>0.05). Traditional CVD risk factors (i.e., blood pressure, cholesterol) and smooth muscle sensitivity to NO were unchanged in both groups (p>0.05). Preliminary assessments suggest greater improvements in endothelial function with N-BRJ in women (Δ=post-pre intervention; ΔFMDBA=1.6±0.4) compared to men (ΔFMDBA=0.9±1.0). Compared to pre-intervention, NO production was (trending) 7% higher (p=0.05) and ROS bioactivity was 25% lower (p=0.02) in HAECs exposed to serum collected post N-BRJ. Serum from PBO had no effects (p>0.05). CONCLUSION: N-BRJ supplementation in ML/O adults with MRD holds promise for improving endothelial function, in part by inducing changes to the circulating milieu that increase NO production and decrease oxidative stress in ECs. The effects on endothelial function may be greater in women compared to men. Targeting the nitrate-nitrite-NO pathway with N-BRJ may be an effective strategy for improving endothelial function in ML/O adults with renal dysfunction to possibly reduce CVD risk. K01DK115524 (MJR); R01AG013038 (DRS); F32HL167552 (KOM); NIH/NCATS CTSA UL1TR002535. 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.

Racial Disparity in Microvascular Function in Men with Newly Diagnosed Prostate Cancer

BACKGROUND:Cardiovascular disease (CVD) is a leading cause of death in men with prostate cancer. In addition, non-Hispanic Black (NHB) men experience worse CVD-related mortality compared to their non-Hispanic White (NHW) counterparts, although the reason for this racial disparity remains unclear. Notably, vascular endothelial dysfunction often precedes the emergence of overt CVD. Indeed, conduit-vessel dysfunction, micro-vascular dysfunction, and arterial stiffness are independent predictors of CVD risk. Thus, the purpose of this study was to comprehensively assess vascular health in recently diagnosed NHB and NHW men with prostate cancer. Methods: Twenty-eight men (10 NHW, 18 NHB) with a new clinical diagnosis of prostate cancer (within 3 months) participated in this study. Flow-mediated dilation (FMD) was performed to represent conduit-vessel vascular endothelial function. Cutaneous post occlusive reactive hyperemia (PORH) with local thermal heating (LTH) and iontophoresis of acetylcholine were performed to represent various mechanisms regulating microvascular function. Lastly, pulse wave velocity (PWV) and pulse wave analysis (PWA) were performed to assess central and aortic stiffness, respectively. Data are reported as mean ± SD. Results: A 4-year age difference ( p=0.131) was observed between NHB (65±7 years) and NHW (69±6 years) men. No differences in BMI or clinical laboratory values were observed between NHB and NHW patients (all p>0.05). NHB men exhibited significantly lower microvascular function compared to NHW men, including PORH (NHB: 117±44 PU vs NHW: 207±47 PU; p<0.001), LTH (NHB: 180±73 PU vs NHW: 281±65 PU; p=0.003), and iontophoresis (NHB: 67±28 PU vs NHW: 136±38 PU; p<0.001). No differences in FMD ( p=0.596), PWV ( p=0.695), or PWA ( p=0.883) were observed between groups. CONCLUSION: The results of the current study provide compelling evidence that microvascular dysfunction is present in NHB men who are recently diagnosed with prostate cancer compared to their NHW counterparts. Given that NHB men were 4 years younger, these data support that the microvascular dysfunction may accelerate vascular aging and contribute to the racial disparity in CVD following prostate cancer diagnosis. Supported by: AHA SFRN 863621 (RAH). 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.

Proteomic Analysis of Prehypertensive and Hypertensive Patients: Exploring the Role of the Actin Cytoskeleton.

Hypertension is a pervasive and widespread health condition that poses a significant risk factor for cardiovascular disease, which includes conditions such as heart attack, stroke, and heart failure. Despite its widespread occurrence, the exact cause of hypertension remains unknown, and the mechanisms underlying the progression from prehypertension to hypertension require further investigation. Recent proteomic studies have shown promising results in uncovering potential biomarkers related to disease development. In this study, serum proteomic data collected from Qatar Biobank were analyzed to identify altered protein expression between individuals with normal blood pressure, prehypertension, and hypertension and to elucidate the biological pathways contributing to this disease. The results revealed a cluster of proteins, including the SRC family, CAMK2B, CAMK2D, TEC, GSK3, VAV, and RAC, which were markedly upregulated in patients with hypertension compared to those with prehypertension (fold change ≥ 1.6 or ≤-1.6, area under the curve ≥ 0.8, and q-value < 0.05). Pathway analysis showed that the majority of these proteins play a role in actin cytoskeleton remodeling. Actin cytoskeleton reorganization affects various biological processes that contribute to the maintenance of blood pressure, including vascular tone, endothelial function, cellular signaling, inflammation, fibrosis, and mechanosensing. Therefore, the findings of this study suggest a potential novel role of actin cytoskeleton-related proteins in the progression from prehypertension to hypertension. The present study sheds light on the underlying pathological mechanisms involved in hypertension and could pave the way for new diagnostic and therapeutic approaches for the treatment of this disease.

Evaluation of Endothelial Dysfunction via Flow-Mediated Dilation in Patients with Inflammatory Bowel Disease Referred to Medical Centers in Kerman

Background: By examining flow-mediated dilatation (FMD) as an index for indirect assessment of arterial endothelial function, this study aimed to investigate the relationship between inflammatory bowel disease (IBD) and early atherosclerosis. Methods: This study was performed on 75 patients with ulcerative colitis, 15 patients with Crohn’s disease, and 75 healthy individuals as the control group. Vascular endothelial function was assessed by FMD and Doppler ultrasonography of the right brachial artery. Results: The mean FMD in IBD patients (12.04±3.8) was lower than that of the persons in the control group (16.68±2.2). Besides, the mean FMD in Crohn’s patients was 12.02±3.5 and the corresponding value in the patients with ulcerative colitis was 12.07±4.2, showing no significant difference (P=0.78). There was a significant opposite relationship between age and FMD in the control group, meaning that as age increased, FMD decreased (r=0.6, P=0.01). However, there was no association between age and FMD among IBD patients. Conclusion: Given that this study focused on people without known risk factors for atherosclerosis, the results pointed to endothelial dysfunction in IBD patients, and IBD can be considered an independent factor in the development of atherosclerosis.

P142 Effect of Atorvastatin on vascular endothelial function in early Systemic Sclerosis: An open label Randomized Controlled trial

Abstract Background/Aims Systemic Sclerosis (SSc) is driven by early endothelial dysfunction, leading to loss of endothelium-dependent vasodilatation. This predisposes to increased stiffness of large arteries. Prospective studies have found a conflicting role of statins in improving vascular function in established SSc. We undertook this study to explore if statins influence endothelium dependent vasodilation in early SSc Methods In this single center open label randomized controlled trial between July 2021 to January 2022, SSc patients (ACR-EULAR 2013) between 18-65 years, with duration &amp;lt; 3 years from the first non-Raynaud’s symptom were included. Those with complicated Raynaud’s, overlap syndromes and cardiovascular comorbidities were excluded. Participants were randomized into statin (atorvastatin 40 mg/day/A40) or no -statin arm. Both groups received stable doses of immunosuppression, during the study period. The primary outcome of flow-mediated dilation (FMD %) of brachial artery, measured by single assessor and secondary outcomes of common carotid intima medial thickness (CIMT), modified Rodnan Skin score (mRSS), Raynaud’s visual analogue scale (RayVAS:0-10), hs CRP, von Willebrand factor and oxidized low-density lipoproteins were measured at baseline and 16 weeks. All patients provided written informed consent; study protocol was approved by IEC(JIP/IEC/2020/026). Considering a change in FMD of 1% between arms as clinically meaningful, sample size was calculated to be 144. Analysis was performed using SPSS v.19.CTRI registration no: REF/2020/07/03495 Results Total 71 eligible patients were randomized into statin(n = 36) and no-statin(n = 35) arms. Baseline parameters were comparable between arms. Baseline mRSS was 14.25. On per-protocol analysis of statin (n = 28) and no-statin (n = 32) arms, there was no significant difference in FMD either at baseline or at 16 weeks (table 1). At week 16, basal brachial artery diameter increased (p = 0.008) in statin arm. Ray VAS scores improved in the statin arm,not achieving significance(p = 0.15). An increase in mRSS from 14 to 16 was noted in no-statin arm , whereas it remained stable in the statin arm (14.5). Secondary endpoints were not met. No adverse events were noted. Conclusion In early SSc, atorvastatin 40 mg/day, added to background immunosuppression, failed to improve endothelial function, assessed using brachial FMD, at 16 weeks. Stabilization of skin tightening was noted in the statin arm. Disclosure A.C. Das: None. M.M. Thabah: None. C. Mariaselvam: None. R. Vijayan: None. A. Anantharaj: None. V. Negi: None.

Sex-specific cardiovascular remodeling leads to a divergent sex-dependent development of heart failure in aged hypertensive rats

IntroductionThe prevalence of heart failure with preserved ejection fraction (HFpEF) is continuously rising and predominantly affects older women often hypertensive and/or obese or diabetic. Indeed, there is evidence on sex differences in the development of HF. Hence, we studied cardiovascular performance dependent on sex and age as well as pathomechanisms on a cellular and molecular level.MethodsWe studied 15-week- and 1-year-old female and male hypertensive transgenic rats carrying the mouse Ren-2 renin gene (TG) and compared them to wild-type (WT) controls at the same age. We tracked blood pressure and cardiac function via echocardiography. After sacrificing the 1-year survivors we studied vascular smooth muscle and endothelial function. Isolated single skinned cardiomyocytes were used to determine passive stiffness and Ca2+-dependent force. In addition, Western blots were applied to analyse the phosphorylation status of sarcomeric regulatory proteins, titin and of protein kinases AMPK, PKG, CaMKII as well as their expression. Protein kinase activity assays were used to measure activities of CaMKII, PKG and angiotensin-converting enzyme (ACE).ResultsTG male rats showed significantly higher mortality at 1 year than females or WT male rats. Left ventricular (LV) ejection fraction was specifically reduced in male, but not in female TG rats, while LV diastolic dysfunction was evident in both TG sexes, but LV hypertrophy, increased LV ACE activity, and reduced AMPK activity as evident from AMPK hypophosphorylation were specific to male rats. Sex differences were also observed in vascular and cardiomyocyte function showing different response to acetylcholine and Ca2+-sensitivity of force production, respectively cardiomyocyte functional changes were associated with altered phosphorylation states of cardiac myosin binding protein C and cardiac troponin I phosphorylation in TG males only. Cardiomyocyte passive stiffness was increased in TG animals. On a molecular level titin phosphorylation pattern was altered, though alterations were sex-specific. Thus, also the reduction of PKG expression and activity was more pronounced in TG females. However, cardiomyocyte passive stiffness was restored by PKG and CaMKII treatments in both TG sexes.ConclusionHere we demonstrated divergent sex-specific cardiovascular adaptation to the over-activation of the renin-angiotensin system in the rat. Higher mortality of male TG rats in contrast to female TG rats was observed as well as reduced LV systolic function, whereas females mainly developed HFpEF. Though both sexes developed increased myocardial stiffness to which an impaired titin function contributes to a sex-specific molecular mechanism. The functional derangements of titin are due to a sex-specific divergent regulation of PKG and CaMKII systems.

Remnant cholesterol trajectory and subclinical arteriosclerosis: a 10-year longitudinal study of Chinese adults

We aimed to identify different trajectories of remnant cholesterol (RC) and investigate the association of RC trajectories with vascular endothelial function and atherosclerosis progression in a longitudinal cohort of the Chinese population. A total of 521 participants were included in the flow-mediated vasodilation (FMD) subcohort study, and 7775 participants were included in the brachial-ankle pulse wave velocity (baPWV) subcohort study. All participants had ≥ 3 medical examinations during the 10-year follow-up period. In the FMD subcohort study, three distinct RC trajectories were identified according to the RC range and changing pattern over time: “low” (57.58%), “moderate” (30.90%) and “high” (11.52%). The proportion of the three groups with vascular endothelial dysfunction (FMD < 7.0%) was 20.00%, 39.75% and 60.00% respectively. Taking the low group as a reference, participants in the moderate and high groups had over 1.88 and 2.94 times the odds of vascular endothelial dysfunction (P = 0.048). In the baPWV subcohort study, three distinct RC trajectories were also identified: “low” (54.29%), “moderate” (38.97%) and “high” (6.74%). The proportion of the three groups with atherosclerosis (baPWV > 1400 cm/s) was 38.79%, 51.26% and 59.01% respectively. Taking the low group as a reference, participants in the moderate and high groups had over 1.46 and 2.16 times the odds of atherosclerosis (P < 0.001). The findings indicated that distinct RC trajectories are significantly associated with vascular endothelial function and atherosclerosis. Regular monitoring to identify persistent increases in RC may be more helpful in identifying individuals with a high risk of cardiovascular disease.

Quinic acid regulated TMA/TMAO-related lipid metabolism and vascular endothelial function through gut microbiota to inhibit atherosclerotic

BackgroundQuinic acid (QA) and its derivatives have good lipid-lowering and hepatoprotective functions, but their role in atherosclerosis remains unknown. This study attempted to investigate the mechanism of QA on atherogenesis in Apoe−/− mice induced by HFD.MethodsHE staining and oil red O staining were used to observe the pathology. The PCSK9, Mac-3 and SM22a expressions were detected by IHC. Cholesterol, HMGB1, TIMP-1 and CXCL13 levels were measured by biochemical and ELISA. Lipid metabolism and the HMGB1-SREBP2-SR-BI pathway were detected by PCR and WB. 16 S and metabolomics were used to detect gut microbiota and serum metabolites.ResultsQA or low-frequency ABX inhibited weight gain and aortic tissue atherogenesis in HFD-induced Apoe−/− mice. QA inhibited the increase of cholesterol, TMA, TMAO, CXCL13, TIMP-1 and HMGB1 levels in peripheral blood of Apoe−/− mice induced by HFD. Meanwhile, QA or low-frequency ABX treatment inhibited the expression of CAV-1, ABCA1, Mac-3 and SM22α, and promoted the expression of SREBP-1 and LXR in the vascular tissues of HFD-induced Apoe−/− mice. QA reduced Streptococcus_danieliae abundance, and promoted Lactobacillus_intestinalis and Ileibacterium_valens abundance in HFD-induced Apoe−/− mice. QA altered serum galactose metabolism, promoted SREBP-2 and LDLR, inhibited IDOL, FMO3 and PCSK9 expression in liver of HFD-induced Apoe−/− mice. The combined treatment of QA and low-frequency ABX regulated microbe-related Glycoursodeoxycholic acid and GLYCOCHENODEOXYCHOLATE metabolism in HFD-induced Apoe−/− mice. QA inhibited TMAO or LDL-induced HCAECs damage and HMGB1/SREBP2 axis dysfunction, which was reversed by HMGB1 overexpression.ConclusionsQA regulated the gut-liver lipid metabolism and chronic vascular inflammation of TMA/TMAO through gut microbiota to inhibit the atherogenesis in Apoe−/− mice, and the mechanism may be related to the HMGB1/SREBP2 pathway.