Changes In Vascular Function Research Articles

Neurological function is restored post-ischemic stroke in zebrafish, with aging exerting a deleterious effect on its pathology.

Ischemic stroke (IS) is a pathological condition characterized by the cessation of blood flow due to factors such as thrombosis, inflicting severe damage to the cranial nervous system and resulting in numerous disabilities including memory impairments and hemiplegia. Despite the critical nature of this condition, therapeutic options remain limited, with a pressing challenge being the development of treatments aimed at restoring neurological function. In this study, we leveraged zebrafish, renowned for their exceptional regenerative capabilities, to analyze the pathology of IS and the subsequent recovery process. We induced photothrombosis in the telencephalon utilizing rose bengal and conducted a temporal investigation of changes in cerebral vascular function and learning ability. Our findings revealed that blood flow in young zebrafish was restored approximately 7 days post-IS induction (dpi), with brain function recuperating by 14 dpi. Furthermore, we observed an escalation in the expression of the neural stem marker gene at 3dpi, followed by an upregulation of the differentiated neuron marker at 7 and 14dpi. In the aged IS model, symptoms were exacerbated. While cerebral blood flow was restored in 7 days, similar to young zebrafish, the recovery of learning ability was protracted in aged fish. Moreover, an upregulation of the differentiated neuron marker seen in young fish was not observed in the aged model. Collectively, our analysis of the zebrafish IS model and its comparison with existing rodent models may lay the groundwork for novel IS treatment strategies. Furthermore, the zebrafish IS model may prove beneficial for analyzing the impact of aging on the pathology of IS and the recovery process.

Caffeine and nicotine acutely inhibits flow-mediated vasodilation, but not both are necessarily harmful in the long term.

Today, flow-mediated dilation (FMD) is a standardized test for the non-invasive assessment of vascular endothelial function in humans. The test is often used to assess the influence of various living conditions on the vascular system. Many factors have a short-term effect on FMD and reduce it. However, not every short-term FMD-reducing effect also signals long-term vascular damage with repeated exposure. The comparison between coffee consumption and smoking will be used to discuss that although both stimulants lead to comparable acute changes in vascular function, they differ in their long-term effects on the vascular system. Therefore, acute FMD effects cannot always be equated with long-term damaging effects.

LncRNA H19 Promotes Angiogenesis in Mouse Pulmonary Artery Endothelial Cells by Regulating the HIF-1α/VEGF Signaling Pathway.

Persistent pulmonary hypertension of the newborn (PPHN) is a syndrome of acute respiratory failure characterized by systemic hypoxemia and elevated pulmonary arterial pressure, which leads to pathological changes in pulmonary vascular remodeling and endothelial cell function. Long non-coding RNA (lncRNA) H19 has been shown to be involved in the regulation of arterial endothelial cell function, but its regulatory role in PPHN is not fully understood. In the present study, mouse pulmonary artery endothelial cells (MPAECs) were cultured in a hypoxic conditions. Subsequently, the regulatory function of lncRNA H19 on MPAECs was explored by constructing adenoviruses knocking down and overexpressing lncRNA H19. The results revealed that the hypoxic conditions could induce the proliferation and migration of MPAECs, as well as the high expression of lncRNA H19 in MPAECs. Knockdown of lncRNA H19 expression in MPAECs reversed hypoxic environment-induced functional changes in endothelial cells, whereas overexpression of lncRNA H19 further enhanced the proliferation and migration of MPAECs. In addition, lncRNA H19 upregulated the hypoxia-inducible factor-1α (HIF-1α)/vascular endothelial growth factor (VEGF) pathway through sponge of miNA-20a-5p, which in turn promoted changes in endothelial cell function. LncRNA H19 may interfere with vascular remodeling in hypoxia-induced pulmonary hypertension by upregulating the expression of HIF-1α and VEGF in vascular endothelial cells.

Characterizing vascular and hormonal changes in women across the life span: a cross-sectional analysis.

Vascular dysfunction, marked by lower endothelial function and increased aortic stiffness, is a nontraditional risk factor that precedes the development of cardiovascular disease (CVD). However, the age at which these changes in vascular function occur in women and the degree to which reproductive hormones mediate these changes has not been characterized. Women free from major disease were enrolled across the adult life span (aged 18-70 yr, n = 140). Endothelial function was assessed as flow-mediated dilation (FMD) of the brachial artery during reactive hyperemia using duplex ultrasound and expressed as percent dilation. Aortic stiffness was measured by carotid-femoral pulse wave velocity (cfPWV). Blood samples were obtained to quantify reproductive hormone concentration. Regression models determined age-related breakpoints and mediating factors between age and vascular outcomes. FMD declined with age with a breakpoint and steeper decline occurring at 47 yr of age. Thereafter, age was independently associated with lower FMD (B = -0.13, P < 0.001). cfPWV was relatively stable until a breakpoint at age 48, and age was independently associated with higher cfPWV thereafter (B = 0.10, P < 0.001). Path analysis revealed that the association between age and FMD was partially mediated by follicle-stimulating hormone (abind = 0.051, P = 0.01) and progesterone (abind = 0.513, P < 0.001) but not estradiol (abind = -0.004, P = 0.08). No mediation was present for cfPWV. Age was associated with endothelial dysfunction and aortic stiffness in women beginning at 47 and 48 yr old, respectively, 3 to 4 yr before the average age of menopause. The association between age and endothelial dysfunction was explained in part by elevations in follicle-stimulating hormone and progesterone, but not declining estradiol.NEW & NOTEWORTHY We demonstrate that the age at which endothelial function declines and aortic stiffness increases in healthy women is 47 and 48, respectively. The inflection point in flow-mediated dilation (FMD) is 6 yr earlier than previously reported, and the association between age and FMD was mediated by follicle-stimulating hormone (FSH) and progesterone (P4) but not estradiol (E2).

HYPERTENSION IN THE ELDERLY: CHALLENGES IN MANAGEMENT AND TREATMENT

Hypertension is a prevalent and significant health issue among the elderly, contributing to increased risks of cardiovascular diseases, stroke, and kidney failure. Managing hypertension in older adults poses unique challenges due to age-related physiological changes, comorbidities, and polypharmacy. This review explores the complex pathophysiology of hypertension in the elderly, including age-related changes in vascular function and the impact of comorbid conditions. It examines the difficulties in diagnosing hypertension, such as variability in blood pressure readings, white coat syndrome, and masked hypertension, highlighting the need for accurate monitoring through home and ambulatory techniques. The review discusses current management strategies, emphasizing the importance of setting appropriate treatment goals, implementing lifestyle modifications, and utilizing pharmacological treatments, including new antihypertensive drugs and combination therapies. It also addresses challenges such as adverse drug reactions, medication adherence, and the management of polypharmacy. Recent advances, including innovations in drug delivery systems and digital health technologies, offer promising solutions for improving hypertension management. Future research directions include exploring precision medicine, understanding the role of the gut microbiome, and addressing health disparities. Clinicians are advised to adopt personalized treatment approaches, integrate technological tools, and address socioeconomic barriers to optimize hypertension management in the elderly. This review underscores the need for ongoing research and tailored strategies to improve outcomes and quality of life for older patients with hypertension.

Abstract P166: Genetic Ablation of the Bile Acid Receptor- Takeda G-protein Coupled Receptor 5 (TGR5) Promotes Weight Gain but Lowers Hypertension

Introduction: TGR5 belongs to G-protein coupled receptor family, that mediates bile acid signaling. Activation of TGR5 by bile acids triggers intestinal glucagon-like peptide-1 secretion, whereby pharmacological activation of TGR5 constitutes a promising incretin-based strategy for the treatment of metabolic disorders. Hypertension is one of the hallmark features of metabolic disorders. We previously reported that hypertension is associated with lower conjugated bile acids, which are ligands for TGR5. Therefore, we hypothesized that lack of activation of TGR5-mediated bile acid signaling promotes not only body weight gain, but also hypertension. Methods: CRISPR/Cas9 technology was used to generate Tgr5 -/- rats from hypertensive Dahl Salt-sensitive (S) rats. Twenty-four-hour blood pressure (BP) readings of 8-weeks-old control female Tgr5 +/+ S rats and age-matched female Tgr5 -/- S rats (n=7/group) were monitored by radiotelemetry for 4 weeks. Body weight, food intake, and water intake were recorded every week. At the end of the study, vascular function was examined using wire myography of dorsal and mesenteric resistance arteries, cardiac function was assessed by echocardiography, and microbiota profiling was conducted via fecal 16S rRNA gene sequencing using Miseq. Results: In support of our hypothesis, despite no difference in food and water intake, at 4 weeks, the body weights of Tgr5 -/- S rats were significantly higher compared to Tgr5 +/+ S rats (236.3gm vs. 225.4gm; p&lt;0.01). Surprisingly, in contrast to our hypothesis, at 4 weeks, Tgr5 -/- S rats had significantly lower systolic BP (151.8mmHg vs. 156.9mmHg, p&lt;0.0001), diastolic BP (107.9mmHg vs. 115.5mmHg, p&lt;0.0001), and mean arterial BP (128.8mmHg vs. 134.9mmHg, p&lt;0.0001) compared to Tgr5 +/+ S rats. However, no significant differences were observed either in vascular reactivity or cardiac function between the groups. Interestingly, fecal microbiota analysis revealed that Tgr5 -/- S rats presented with significant remodeling of gut microbiota with lower α-diversity (observed features; p=0.05), b-diversity (Bray-Curtis; p&lt;0.05, Jaccard; p&lt;0.01), and higher relative abundance of the BP-lowering genera Akkermansia . Conclusion: Our study revealed that deletion of TGR5 resulted in weight gain but lowered BP. It implies that activation of TGR5 may be a risk factor for raising BP. The mechanism by which TGR5 regulates BP seem independent of changes in vascular or cardiac function but is likely mediated by gut microbiota.

House cricket protein hydrolysates alleviate hypertension, vascular dysfunction, and oxidative stress in nitric oxide-deficient hypertensive rats.

Edible insects with high protein content and bioactive peptides with health promotion against chronic disease. Deficiency of nitric oxide (NO) contributes to hypertension, a leading cause of cardiovascular diseases and death worldwide. This study assessed the antihypertensive effects of house cricket protein hydrolysates (HCPH) in NO-deficient hypertensive rats. Male Sprague-Dawley rats (n = 12/group) were hypertensive after the administration of Nω-nitro-L-arginine methyl ester (L-NAME) at a dose of 50 mg/kg body weight (BW)/day in drinking water for 7 weeks. The animals were then treated with HCPH (250 or 500 mg/kg BW/day) or lisinopril (Lis) (1 mg/kg BW/day) for the last 4 weeks of L-NAME administration. Blood pressure (BP), vascular function, and structural changes, endothelial NO synthase (eNOS), and p47phox nicotinamide adenine dinucleotide phosphate (NADPH) oxidase protein expression in aortic tissues, plasma nitrate/nitrite, plasma angiotensin-converting enzyme (ACE) activity, and oxidative stress markers in blood and tissues were evaluated. Induction of hypertension resulted in significantly elevated BP, decreased plasma nitrate/nitrite concentration, abolished vascular function, and increased vascular wall thickness. Overproduction of carotid and mesenteric superoxide, increased plasma, heart, and kidney malondialdehyde, and protein carbonyl levels, and increased plasma ACE activity were observed. Down-expression of eNOS with overexpression of p47phox NADPH oxidase subunit was also found in L-NAME hypertensive rats. Oral treatment with HCPH, particularly at a dose of 500 mg/kg BW/day, significantly alleviated these alterations in a manner comparable to that of Lis. HCPH improved vascular function and exerted antihypertensive effects, mainly due to the improvement of NO bioavailability, reduction of oxidative stress, and inhibition of ACE.

Novel genes involved in vascular dysfunction of the middle temporal gyrus in Alzheimer's disease: transcriptomics combined with machine learning analysis.

Studies have shown that vascular dysfunction is closely related to the pathogenesis of Alzheimer's disease. The middle temporal gyrus region of the brain is susceptible to pronounced impairment in Alzheimer's disease. Identification of the molecules involved in vascular aberrance of the middle temporal gyrus would support elucidation of the mechanisms underlying Alzheimer's disease and discovery of novel targets for intervention. We carried out single-cell transcriptomic analysis of the middle temporal gyrus in the brains of patients with Alzheimer's disease and healthy controls, revealing obvious changes in vascular function. CellChat analysis of intercellular communication in the middle temporal gyrus showed that the number of cell interactions in this region was decreased in Alzheimer's disease patients, with altered intercellular communication of endothelial cells and pericytes being the most prominent. Differentially expressed genes were also identified. Using the CellChat results, AUCell evaluation of the pathway activity of specific cells showed that the obvious changes in vascular function in the middle temporal gyrus in Alzheimer's disease were directly related to changes in the vascular endothelial growth factor (VEGF)A-VEGF receptor (VEGFR) 2 pathway. AUCell analysis identified subtypes of endothelial cells and pericytes directly related to VEGFA-VEGFR2 pathway activity. Two subtypes of middle temporal gyrus cells showed significant alteration in AD: endothelial cells with high expression of Erb-B2 receptor tyrosine kinase 4 (ERBB4high) and pericytes with high expression of angiopoietin-like 4 (ANGPTL4high). Finally, combining bulk RNA sequencing data and two machine learning algorithms (least absolute shrinkage and selection operator and random forest), four characteristic Alzheimer's disease feature genes were identified: somatostatin (SST), protein tyrosine phosphatase non-receptor type 3 (PTPN3), glutinase (GL3), and tropomyosin 3 (PTM3). These genes were downregulated in the middle temporal gyrus of patients with Alzheimer's disease and may be used to target the VEGF pathway. Alzheimer's disease mouse models demonstrated consistent altered expression of these genes in the middle temporal gyrus. In conclusion, this study detected changes in intercellular communication between endothelial cells and pericytes in the middle temporal gyrus and identified four novel feature genes related to middle temporal gyrus and vascular functioning in patients with Alzheimer's disease. These findings contribute to a deeper understanding of the molecular mechanisms underlying Alzheimer's disease and present novel treatment targets.

Exploring autism via the retina: Comparative insights in children with autism spectrum disorder and typical development.

Autism spectrum disorder (ASD) is a widely recognized neurodevelopmental disorder, yet the identification of reliable imaging biomarkers for its early diagnosis remains a challenge. Considering the specific manifestations of ASD in the eyes and the interconnectivity between the brain and the eyes, this study investigates ASD through the lens of retinal analysis. We specifically examined differences in the macular region of the retina using optical coherence tomography (OCT)/optical coherence tomography angiography (OCTA) images between children diagnosed with ASD and those with typical development (TD). Our findings present potential novel characteristics of ASD: the thickness of the ellipsoid zone (EZ) with cone photoreceptors was significantly increased in ASD; the large-caliber arteriovenous of the inner retina was significantly reduced in ASD; these changes in the EZ and arteriovenous were more significant in the left eye than in the right eye. These observations of photoreceptor alterations, vascular function changes, and lateralization phenomena in ASD warrant further investigation, and we hope that this work can advance interdisciplinary understanding of ASD.

Molecular Mechanisms of Plant Extracts in Protecting Aging Blood Vessels.

Plant Extracts (PE) are natural substances extracted from plants, rich in various bioactive components. Exploring the molecular mechanisms and interactions involved in the vascular protective effects of PE is beneficial for the development of further strategies to protect aging blood vessels. For this review, the content was obtained from scientific databases such as PubMed, China National Knowledge Infrastructure (CNKI), and Google Scholar up to July 2024, using the search terms "Plant extracts", "oxidative stress", "vascular aging", "endothelial dysfunction", "ROS", and "inflammation". This review highlighted the effects of PE in protecting aging blood vessels. Through pathways such as scavenging reactive oxygen species, activating antioxidant signaling pathways, enhancing respiratory chain complex activity, inhibiting mitochondrial-reactive oxygen species generation, improving nitric oxide bioavailability, downregulating the secretion of inflammatory factors, and activating sirtuins 1 and Nrf2 signaling pathways, it can improve vascular structural and functional changes caused by age-related oxidative stress, mitochondrial dysfunction, and inflammation due to aging, thereby reducing the incidence of age-related cardiovascular diseases.

Phosphodiesterase 9A inhibition improves aging-related increase in pulmonary vascular resistance in mice.

As individuals age, there is a gradual decline in cardiopulmonary function, often accompanied by cardiac pump dysfunction leading to increased pulmonary vascular resistance (PVR). Our study aims to investigate the changes in cardiac and pulmonary vascular function associated with aging. Additionally, we aim to explore the impact of phosphodiesterase 9A (PDE9A) inhibition, which has shown promise in treating cardiometabolic diseases, on addressing left ventricle (LV) dysfunction and elevated PVR in aging individuals. Young (3 months old) and aged (32 months old) male C57BL/6 mice were used. Aged mice were treated with the selective PDE9A inhibitor PF04447943 (1 mg/kg/day) through intraperitoneal injections for 10 days. LV function was evaluated using cardiac ultrasound, and PVR was assessed in isolated, ventilated lungs perfused under a constant flow condition. Additionally, changes in PVR were measured in response to perfusion of the endothelium-dependent agonist bradykinin or to nitric oxide (NO) donor sodium nitroprusside (SNP). PDE9A protein expression was measured by Western blots. Our results demonstrate the development of LV diastolic dysfunction and increased PVR in aged mice. The aged mice exhibited diminished decreases in PVR in response to both bradykinin and SNP compared to the young mice. Moreover, the lungs of aged mice showed an increase in PDE9A protein expression. Treatment of aged mice with PF04447943 had no significant effect on LV systolic or diastolic function. However, PF04447943 treatment normalized PVR and SNP-induced responses, though it did not affect the bradykinin response. These data demonstrate a development of LV diastolic dysfunction and increase in PVR in aged mice. We propose that inhibitors of PDE9A could represent a novel therapeutic approach to specifically prevent aging-related pulmonary dysfunction.

Associations of retinal microvascular alterations with diabetes mellitus: an OCTA-based cross-sectional study

BackgroundDiabetes, a health crisis afflicting millions worldwide, is increasing rapidly in prevalence. The microvascular complications triggered by diabetes have emerged as the principal cause of renal disease and blindness. The retinal microvascular network may be sensitive to early systemic vascular structural and functional changes. Therefore, this research endeavored to discern the systemic determinants influencing the retinal microvascular network in patients with and without diabetes.MethodsThe Kailuan Eye Study is a cross-sectional study based on the community-based cohort Kailuan Study. Participants underwent optical coherence tomography angiography (OCTA) (Zeiss Cirrus 5000; Carl Zeiss Meditec) and comprehensive systemic examination. Metrics such as perfusion density (PD), vascular density (VD), foveal avascular zone (FAZ) parameters of the superficial capillary plexus (SCP) in the macula were assessed.ResultsThis study included 860 eligible participants (average age = 62.75 ± 6.52 years; 21.9% female), of which 449 were diabetics. People with diabetes had diminished PD and VD in the entire macular and parafoveal regions compared to people without diabetes. Reduced PD in the whole macular region was correlated with higher fasting plasma glucose (FPG, mmol/L) concentration (Beta = -0.19, 95% CI = -0.42 to -0.36, P < 0.001), longer axial length (AL, mm) (Beta = -0.13, 95%CI = -0.48 to -0.25, P = 0.002), and elevated heart rate (Beta = -0.10, 95%CI = -0.14 to -0.19, P = 0.014), after adjusting for younger age (Beta = -0.18, 95%CI = -0.24 to -0.35, P < 0.001), consistent with VD of the whole macular region. A higher FPG level was significantly correlated with lower SCP density of both PD and VD in the macular and parafoveal region (P < 0.05 for all), as well as increased systolic blood pressure and low-density lipoprotein cholesterol concentration (P < 0.01 for all).ConclusionsIn this large-sample cross-sectional study, OCTA evaluation revealed that high prevalence of diabetes and elevated FPG levels were correlated with reduced retinal VD and PD. Hypertension and hyperlipidemia are important risk factors for the development of atherosclerotic cardiovascular disease but have no significant effect on retinal microvascular abnormalities.

Increased vascular stiffness in children exposed in utero but not children exposed postnatally to emissions from a coal mine fire.

Chronic, low-intensity air pollution exposure has been consistently associated with increased atherosclerosis in adults. However, there was limited research regarding the implications of acute, high-intensity air pollution exposure during childhood. We aimed to determine whether there were any associations between early-life exposure to such an episode and early-life vascular function changes. We conducted a prospective cohort study of children (<9 years old) who lived in the vicinity of the Hazelwood coal mine fire (n = 206). Vascular function was measured using noninvasive diagnostic methods including carotid intima-media thickness and pulse wave velocity (PWV). Exposure estimates were calculated from prognostic models and location diaries during the exposure period completed by each participant's parent. Linear mixed-effects models were used to determine whether there were any associations between exposure and changes in vascular outcomes at the 3- and 7-year follow-ups and over time. At the 7-year follow-up, each 10 μg/m3 increase in daily PM2.5 in utero was associated with increased PWV (β = 0.13 m/s; 95% confidence interval [CI] = 0.02, 0.24; P = 0.02). The association between in utero exposure to daily PM2.5 was not altered by adjustment for covariates, body mass index, and maternal fire stress. Each 1 µg/m3 increase in background PM2.5 was associated with increased PWV (β = 0.68 m/s; 95% CI = 0.10, 1.26; P = 0.025), in children from the in utero exposure group. There was a trend toward smaller PWV (β = -0.17 m/s; 95% CI = -0.366, 0.02) from the 3- to 7-year follow-up clinic suggesting that the deficits observed previously in children exposed postnatally did not persist. There was a moderate improvement in vascular stiffness of children exposed to PM2.5 from a local coal mine fire in infancy. There was a mild increase in vascular stiffness in children exposed to PM2.5 from a local coal mine fire while their mothers were pregnant.

Dietary Effect on Peripheral and Cerebral Vascular Function in Adults with Non-Alcoholic Fatty Liver Disease

Objective: Non-alcoholic fatty liver disease (NAFLD) is a recognized independent risk factor for cardiovascular and cerebrovascular dysfunction. The present study evaluated the effect of dietary interventions on peripheral and cerebral vascular function in individuals with NAFLD. Methods: We studied 30 middle-aged adults (55±9 years) with NAFLD or with elevated NAFLD risk (with prediabetes symptoms). Liver fat content was assessed via 1H magnetic resonance spectroscopy. NAFLD was defined as liver fat proton density fat fraction (PDFF) exceeding 5%. Participants were randomly assigned to a low-carbohydrate diet (carbohydrate intake &lt;30 g/d) or a low-calorie diet (30% calorie intake reduction). Arterial stiffness (via brachial-ankle pulse wave velocity-baPWV), carotid artery intima-media thickness (IMT), endothelium-dependent vasodilation (via flow-mediated dilation-FMD), cerebrovascular reactivity (CVR) in the middle cerebral artery (MCA), and blood concentrations of cardiovascular risk factors were measured before and after a two-week dietary intervention. Results: Participants with NAFLD represented 70% of the current cohort. Following the dietary interventions, participants had significant reductions in body weight (95%CI [-3.22, -1.41 kg]) and fat mass (95%CI [-1.64, -0.56 kg]), accompanied by decreased liver fat content (95%CI [-2.62, -0.79%]). These changes were only evident in the NAFLD group with no significant differences between the two dietary interventions. Systolic and diastolic blood pressure as well as pulse pressure significantly decreased in both NAFLD and non-NAFLD groups. Total cholesterol (95%CI [-22.2, -1.5 mg/dL]) and triglyceride (95%CI [-30.4, -0.9 mg/dL]) concentrations decreased in those with NAFLD assigned to the low-carbohydrate diet. baPWV decreased (95%CI [-78.6, -12.4 cm/s]) only in individuals with NAFLD assigned to the low-calorie diet. FMD significantly increased (95%CI [0.5, 5.1%]) only in individuals with NAFLD assigned to the low-carbohydrate diet. Lower baseline liver fat content was associated with greater improvement in FMD (r=-0.60, p=0.008) in the NAFLD group. Carotid IMT and cerebrovascular parameters (e.g., pulsatility index, CVR, MCA blood flow velocity) remained unchanged in any groups. Changes in vascular function were not associated with the corresponding changes in liver fat content. Conclusion: The two-week dietary intervention involving either a low-carbohydrate or low-calorie diet elicited significant reductions in liver fat content and improvements in peripheral arterial stiffness and endothelium-dependent vasodilation in adults with NAFLD. UT Aging Initiatives. 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.

Aging Related Changes in Smooth Muscle Contractile and Regulatory Proteins

Aging is a significant risk factor for cardiovascular disease and is known to be associated with an increase in vascular stiffness and decrease in sensitivity to NO mediated vasodilatation. However, the underlying mechanism for these changes in vascular function is unknown. Smooth muscle tone is known to be regulated by the expression and phosphorylation of both nonmuscle (NM) and smooth muscle (SM) myosin. NM and SM phosphorylation is regulated by the activity of myosin light chain kinase (MLCK) and MLC phosphatase. MLC phosphatase is a trimeric enzyme consisting of enzymatic, myosin targeting (MYPT1) and a 20kDa subunit of unknown function. Two isoforms of MYPT1 are produced by alternative mRNA splicing, which differ by the presence or absence of a COOH-terminal leucine zipper (LZ+/-), and the relative expression of LZ+/LZ- MYPT1 determines the sensitivity to NO mediated vasodilatation. We defined NM myosin expression using two-dimensional SDS PAGE and LZ+/LZ- MYPT1 expression using immunoblotting in aortic and tertiary mesenteric smooth muscle from 6mo and 24mo old Fischer344 rats. The data demonstrate that aging is associated with a significant decrease in the expression of both LZ+ MYPT1 and NM myosin. The reduction in LZ+ MYPT1 expression would both decrease the sensitivity to NO mediated smooth muscle dilatation and increase vascular tone, which is a hallmark of the vasculature in aging. On the other hand, the reduction in NM myosin would result in a decrease in vascular tone and could represent a compensatory mechanism to normalize blood pressure during aging. These data demonstrate that there are changes in the expression of smooth muscle regulatory and contractile proteins during aging and these changes in protein expression contribute to molecular mechanism for the decrease in sensitivity to NO mediated vasodilatation as well as the increase in vascular tone or the vascular dysfunction that occurs with aging. Supported by a Mayo CV Prospective Grant (FVB). 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 mesenteric artery passive mechanical properties in adult APOE3 &amp; APOE4 Mice

Previous studies from our lab have demonstrated changes in vascular structure and function in posterior cerebral arteries and left common carotid artery (CA) in adult male and female mice expressing human-ApoE targeted replacement of APOE3 (B6.129P2-Apoetm2(APOE*3)MaeN8) and APOE4 (B6.129P2-Apoetm3(APOE*4)MaeN8) (Taconic Labs). Therefore, we hypothesized that similar changes may be observed in the systemic circulation. We isolated 4thor 5th-order mesenteric arteries from adult 6-month-old male and female mice expressing hAPOE3 (n=5) or hAPOE4 (n=4). Mesenteric artery segments (5-8 mm in length) were isolated and cannulated on an arteriograph to assess vascular mechanical properties; lumen diameter, wall thickness, wall:lumen ratio, distensibility, stress versus strain (SvS), compliance, incremental modulus of elasticity (Einc), and calculated pulse wave velocity under passive conditions (Ca2+-free Krebs plus diltiazem) at intraluminal pressures ranging from 10mmHg to 140mmHg. In addition, phenylephrine-induced contraction and potassium-induced contraction were assessed using Ca2+-containing Krebs. Data was analyzed using two-way ANOVA, Student’s t-test, and analysis of nonlinear fit. Values were considered statistically different at p&lt;0.05. In our preliminary data, lumen diameter, distensibility, compliance, strain, and calculated pulse wave velocity were similar in APOE3 and APOE4 mice. Wall thickness and wall:lumen ratio were significantly greater in APOE4 compared to APOE3 mice. Wall stress and Einc were significantly less in APOE4 compared to APOE3 mice. Interestingly, the APOE4 mice exhibited a significantly lesser stress per given amount of strain compared to the APOE3 mice. Phenylephrine- and potassium-induced contractions were similar in APOE3 and APOE4 mice. This data suggests there are changes in passive mechanical properties in small mesenteric arteries from APOE4 mice, which resemble a hypertensive phenotype. ABRC/ADHS18-205211 (DME, CBJ), Arizona Alzheimer’s Consortium (funded by the Arizona Department of Health Services, Contract No. CTR040636) and matching funds from Midwestern University (DME), Biomedical Sciences Program (SM, IW, DME), Biomedical Sciences Start-up Funds (DME). 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.

Acute Effects of Combining Weight and Elastic Resistance Exercise on Vascular Function in Older Adults.

Prior research has suggested that resistance exercise may result in a temporary decrease in vascular function, as measured by flow-mediated dilation (FMD), among untrained young individuals. However, the immediate impact of combined elastic and weight resistance training on older adults remains insufficiently explored. We assessed vascular function before, after, and 30 min after acute exercise under three resistance conditions to evaluate whether a combination of weight and elastic resistance exercises has an acute effect on vascular function in older adults. Fourteen older adults (65.6 ± 2.9 years) executed three sets of 12 repetitions at 65% of one repetition maximum (1 RM) of the bench press (BP) exercise. Testing was performed on three separate days as follows: (1) barbell alone (BA); (2) barbell plus elastic bands (10% of 65% 1 RM) (BE10); and (3) barbell plus elastic bands (20% of 65% 1 RM) (BE20). A two-way (time × condition) repeated measures analysis of variance was employed to assess the time and condition effects on flow-mediated dilation (FMD) and pulse wave velocity (PWV). At 0 min post-exercise, FMD was significantly higher during BE10 than during BA (p < 0.05); however, at 30 min post-exercise, no significant difference (p ≥ 0.05) was observed between the three conditions. In each condition, FMD results did not differ significantly at different times (p ≥ 0.05). For FMD, the main effect of the condition (F[2,26] = 3.86, p = 0.034) and that of the time and condition (F[4,52] = 3.66, p = 0.011) were significant. For PWV, only the difference between the BA and BE10 conditions was significant at 0 min (p < 0.05). PWV increased from baseline in the BA condition (p < 0.05) but not significantly in the BE10 and BE20 conditions (p ≥ 0.05). Therefore, BA, BE10, and BE20 demonstrated various changes in vascular function. Long-term training intervention studies are needed to validate these findings.

The effects of telerehabilitation in adults with complex biventricular congenital heart conditions: protocol for a multi-centre, randomised controlled trial—CH-FIT

BackgroundAccumulated evidence suggests that exercise training exerts beneficial effects on people with congenital heart conditions. These findings are predominantly derived from small, single-centre exercise trials conducted in outpatient rehabilitation facilities. In recent years, the delivery of exercise interventions remotely has increased through digital communications technology (telerehabilitation). However, very little research to date has been conducted into the efficacy of telerehabilitation in people with a congenital heart condition.AimsTo evaluate the effects of a telehealth-delivered exercise intervention in people with a history of a surgical biventricular repair due to a congenital heart condition.MethodsOne hundred eligible adolescent (≥ 16 years) and adult participants living with a complex biventricular congenital heart condition will be recruited from four Australian sites and randomised to either (1) a 16-week telehealth-delivered combined (aerobic and resistance) exercise training programme of moderate-to-vigorous intensity or (2) usual care (control group), in a 1:1 allocation, with an 8-month follow-up.Outcomes of interestThe primary outcome will be the change in aerobic capacity expressed as peak oxygen uptake (VO2peak). Secondary outcomes will include changes in vascular function, muscle oxygenation, metabolic profile, body composition and musculoskeletal fitness, neurohormonal activation, neurocognitive function, physical activity levels, dietary and nutritional status, and quality of life. Outcomes will be assessed at baseline, 16 weeks, and 12 months (to determine longer-term maintenance potential).DiscussionIf found to be efficacious, telerehabilitation may be an alternative option for delivering exercise, improving health outcomes, and increasing accessibility to exercise programmes. Efficacy data is required to quantify the clinical significance of this delivery mode of exercise.Trial registrationACTRN12622000050752Trial registration date: 17 January 2022Trial registration URL: https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=382635&showOriginal=true&isReview=trueTrial registry name: Australian and New Zealand Clinical Trials Registry

Maresin-1 ameliorates hypertensive vascular remodeling through its receptor LGR6.

Hypertensive vascular remodeling is defined as the changes in vascular function and structure induced by persistent hypertension. Maresin-1 (MaR1), one of metabolites from Omega-3 fatty acids, has been reported to promote inflammation resolution in several inflammatory diseases. This study aims to investigate the effect of MaR1 on hypertensive vascular remodeling. Here, we found serum MaR1 levels were reduced in hypertensive patients and was negatively correlated with systolic blood pressure (SBP). The treatment of MaR1 reduced the elevation of blood pressure and alleviated vascular remodeling in the angiotensin II (AngII)-infused mouse model. In addition, MaR1-treated vascular smooth muscle cells (VSMCs) exhibited reduced excessive proliferation, migration, and phenotype switching, as well as impaired pyroptosis. However, the knockout of the receptor of MaR1, leucine-rich repeat-containing G protein-coupled receptor 6 (LGR6), was seen to aggravate pathological vascular remodeling, which could not be reversed by additional MaR1 treatment. The mechanisms by which MaR1 regulates vascular remodeling through LGR6 involves the Ca2+/calmodulin-dependent protein kinase II/nuclear factor erythroid 2-related factor 2/heme oxygenase-1 signaling pathway. Overall, supplementing MaR1 may be a novel therapeutic strategy for the prevention and treatment of hypertension.

A Meta-Analysis for Postoperative Alternations of Aortic Coarctation.

To investigate postoperative vascular changes of patients with coarctation of the aorta (CoA). Literature review of updated articles was performed in June 2023 through the following databases: PubMed, Web of Science, EMBASE, Crohrane Library, CNKI and Wanfang database. All the case-control studies regarding the postoperative changes of vascular structure and function in patients with CoA were analyzed. A total of 596 articles from the above databases were initially identified, with 10 articles being selected for meta-analysis. The analysis showed that weighted mean difference (WMD) of carotid intima-media thickness (cIMT) was 0.07 (95% CI = 0.01~0.13, p < 0.01) and WMD of flow mediated dilation (FMD) was -4.36 (95% CI = -7.49~-1.24, p < 0.01), respectively. The postoperative cIMT of CoA patients was higher than that of the control group, but the postoperative FMD was lower than that of the control group. The operation on CoA patients ameliorates anatomical deformity in the vascular structures. However, intima-media thickening and endothelial malfunction remain as the key postoperative issues.