Endothelium-dependent Vasodilation Research Articles

TNFa-TNFRI interaction impairs endothelial calcium signaling and elevates blood pressure in obesity

Endothelial dysfunction in small arteries is a hallmark of obesity-induced hypertension. Recent studies show that the formation of peroxynitrite, a reactive nitrogen species, impairs endothelium-dependent vasodilation. It is well known that inflammatory cytokines promote the formation of cellular peroxynitrite. In this regard, tumor necrosis factor-alpha (TNFα) signaling has been proposed as a contributor to endothelial dysfunction in obesity. Notably, the vascular wall has been proposed as a source of TNFα generation in obesity, although the vascular TNFα signaling mechanisms in obesity are unclear. We hypothesized that vascular wall-derived TNFα acts locally to impair endothelial function in obesity. We previously reported that high-fat diet feeding (60% kcal fat) for 14 weeks elevates blood pressure in mice. Flow cytometry and mRNA expression studies indicated an increase in TNFα levels in freshly isolated SMCs from small mesenteric arteries (MAs) of high-fat diet-fed obese mice compared to normal chow-fed control mice. However, TNFα levels in endothelial cells (ECs) from obese mice were not different from those in ECs from control mice. Tamoxifen-inducible SMC-specific TNFα -/- (TNFα SMC -/- ) mice did not show an increase in blood pressure after high-fat diet feeding. However, tamoxifen-inducible EC-specific TNFα -/- (TNFα EC -/- ) mice showed a similar increase in blood pressure after high-fat diet feeding compared to the control mice. Both TNFα SMC -/- and TNFα EC -/- showed a similar increase in body weight after high-fat diet feeding when compared to control mice, suggesting that differences in weight gain did not contribute to lower blood pressure in obese TNFα SMC -/- mice. Together, these results indicated that SMC TNFα plays a critical role in blood pressure elevation in obesity. The pro-inflammatory effects of TNFα occur mainly through TNFα receptor-I (TNFRI) activation. Therefore, we postulated that TNFα released from SMCs acts locally on EC TNFRI. Endothelium-dependent vasodilation to acetylcholine was improved in obese TNFα SMC -/- mice compared to obese control mice. Previous studies showed that decreased Ca 2+ influx through endothelial TRPV4 (transient receptor potential vanilloid 4) channels contribute to blood pressure elevation in obese mice. The activity of TRPV4 channels is also improved in ECs from obese TNFα SMC -/- mice. Treatment with a selective TNFRI signaling inhibitor (R7050, 10 mg/kg, i.p., once a day for 14 days) reduced the blood pressure to normal levels in obese mice but did not affect blood pressure in control mice. R7050 treatment also restored endothelium-dependent dilation of MAs and the activity of TRPV4 channels in ECs. Collectively, our findings indicate that vascular TNFα impairs endothelial calcium signaling and elevates blood pressure in obesity, highlighting the role of SMCs as a source of TNFα in obesity This is the full abstract presented at the American Physiology Summit 2023 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.

Creating the Phenotype of Preeclamptic Endothelial Dysfunction in Placental Vessels

Objective: To determine if placental vessel endothelial dysfunction can be produced in control vessels by exposure to preeclamptic plasma, establishing a model to further explore the mechanisms of dysfunction and therapeutics to restore function in preeclampsia. Hypothesis: Preeclamptic plasma administered to unaffected vessels induces endothelial dysfunction. Methods: Placental microvessels were dissected from the maternal side of placentas from patients consented to the Medical College of Wisconsin Maternal Research Placenta and Cord Blood Bank. Control vessels were treated with 10% healthy maternal plasma or 10% preeclamptic (PreE) maternal plasma within the vessel lumen for 12-16 hours[MJ1]. PreE vessels were not treated with plasma. Microvessels were then cannulated on glass micropipettes, pressurized to 60mmHg and constricted with 0.1-1.0 nM Endothelin-1 (ET-1). A 1-100cm H2O pressure gradient was applied and the inner diameter of the vessel was measured by video microscopy. The change in diameter was calculated as a % of maximum diameter as assessed by exposure to 100μM papaverine. Flow mediated dilation (FMD) was evaluated by a two-way ANOVA test with Dunnett’s multiple comparisons. The maximum dilation values were evaluated by a Kruskal-Wallis test with Dunn’s multiple comparative test or t-test as appropriate. FMD is evaluated as mean +/- SEM. Data: Control vessels at maximum flow dilated to 81.1 % ± 7.1 % (n=5), whereas vessel from PreE placentas dilated to 36.9 % ± 8.6% (n=3,). Incubation of control vessels with normal plasma resulted in maximal dilation of 80.6% ± 3.3%, n=3. Control vessels incubated with plasma from PreE patients dilated to 44.7% ± 4.7%. n=3). Summary of Results: Control vessels dilated significantly more than PreE vessels when evaluated by t-test (p=0.05). Incubation of control vessels with normal plasma did not change maximal dilation (p>0.99). Control vessels incubated with PreE plasma demonstrated a near significant drop in dilatory capacity (p=0.05). PreE plasma exposed vessels compared to untreated PreE vessels showed no significant difference (p=0.46[DDG2] ).When comparing overall flow mediated dilatory responses in these vessels there is a significant difference observed between control vessels, control vessels treated with PreE plasma, and PreE vessels at 50cm H2O (p<0.05). This difference is even more significant (p<0.01) at the maximum pressure gradient when analyzed by two-way ANOVA. There is no significant difference at any point between control vessels and control vessels treated with normal plasma as evaluated by two-way ANOVA (p>0.99). Conclusions: The addition of PreE plasma to control vessels demonstrates similar impairment in endothelium-dependent vasodilation as seen in untreated PreE vessels. Future directions will include evaluation of the mechanisms of vasodilation and therapeutic options that could restore endothelial function in PreE vessels. NHLBI 1K08HL150340-01 This is the full abstract presented at the American Physiology Summit 2023 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.

ADAM17 overexpression improves cerebrovascular vasoreactivity and cognitive function in the APP/PS1 mouse model of Alzheimer's disease

The disintegrin and metalloproteinase 17 (ADAM17) exhibits α-secretase activity, whereby it can prevent the production of neurotoxic amyloid precursor protein-α (APP). ADAM17 is abundantly expressed in vascular endothelial cells and may act to regulate vascular homeostatic responses, including vascular growth and vasomotor function. We hypothesized that cerebrovascular ADAM17 plays a role in the pathogenesis of Alzheimer’s disease (AD). Here we found that 8-10 months old APP/PS1 mice (expressing transgenes for APP Swedish mutation and PSEN1 with L166P mutation) with significant cognitive deficits display a markedly reduced expression of ADAM17 in cerebral microvessels. Systemic delivery and AAV-mediated re-expression of ADAM17 in APP/PS1 mice improved cognitive functioning, without affecting β-amyloid plaque density. Moreover, we found that the endothelium-dependent vasodilator function of isolated and pressurized cerebral arteries in APP/PS1 mice was impaired, which was restored to normal levels by the ADAM17 re-expression. The cerebral microvascular network density in the APP/PS1 mice before or after ADAM17 re-expression was not affected. In addition, proteomic analysis identified several differentially expressed molecules involved in AD neurodegeneration and repair that were reversed by ADAM17 re-expression. Thus, we propose that a reduced ADAM17 expression in cerebral microvessels impairs vasodilator function, whereby it contributes to the development of cognitive dysfunction in APP/PS1 mice, and that ADAM17 can potentially be targeted for therapeutic intervention in AD. T32HL155011; 20PRE35211126 This is the full abstract presented at the American Physiology Summit 2023 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.

Nitric oxide contribution to endothelium-mediated vasodilation is attenuated in postmenopausal compared to premenopausal females

Background: Hypertension prevalence increases in females following menopause. Poor endothelial microvascular function increases risk of hypertension. Endothelial-mediated vasodilation is dependent on nitric oxide (NO). Estrogen enhances NO production; therefore, reduced estrogen levels in postmenopausal females may result in a reduced contribution of NO to endothelial-mediated vasodilation, although studies are limited. Herein, we aimed to investigate the contribution of NO to endothelial-mediated vasodilation in premenopausal and postmenopausal females. We hypothesized that postmenopausal females would have attenuated endothelium-mediated vasodilation and reduced contribution of NO compared to premenopausal females. Methods: Ten premenopausal (27±3 yrs) and eleven postmenopausal (59±4 yrs) normotensive females were studied. Resting brachial blood pressures were measured using a standard arm cuff. Brachial arterial catheters were placed for continuous blood pressure measurement and pharmacologic infusions. Forearm blood flow (FBF) was measured using venous occlusion plethysmography at baseline (saline) and during infusion of an endothelium-dependent vasodilator (acetylcholine; 1.0, 2.0, 4.0, and 8.0 μg/100mL tissue/min) with and without a NO synthase inhibitor (L-NG-monomethylarginine [L-NMMA]; 1.0 mg/min) co-infusion. Forearm vascular conductance (FVC) was calculated as FBF/mean arterial pressure✕100. Data were analyzed using a two-way repeated-measures ANOVA. Results: Resting systolic blood pressure (SBP) but not diastolic blood pressure (DBP) was greater in postmenopausal compared to premenopausal females (SBP: 121±15 vs. 103±9 mmHg, respectively; P<0.01; DBP: 72±11 vs. 65±5 mmHg, respectively; P=0.07). FBF responses to acetylcholine did not differ between premenopausal and postmenopausal females (Group Main Effect: P=0.11). When correcting for blood pressure, premenopausal females exhibited greater FVC responses to acetylcholine compared to postmenopausal females (Group Main Effect: P=0.04). In premenopausal females, FBF and FVC responses to acetylcholine were reduced with co-infusion of L-NMMA compared to acetylcholine infusion only (L-NMMA Main Effect: P=0.02 and P=0.01, respectively). In postmenopausal females, the FBF and FVC responses to acetylcholine were unaffected by L-NMMA (L-NMMA Main Effect: P=0.79 and P=0.76, respectively). Conclusion: Compared to premenopausal females, postmenopausal females have impaired endothelial microvascular function. Attenuated NO contribution during endothelium-mediated vasodilation in postmenopausal women may partially contribute to the increased hypertension risk in this population. AHA 14PRE18040000, AHA 898649, NIH HL083947, NIH HL148144, NCATS UL1 TR000135 This is the full abstract presented at the American Physiology Summit 2023 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 effects of standard and soy-free chow on cerebral artery function in ovariectomized female mice

As females age, they transition through menopause, experiencing a decrease in estrogen and an increase in cardiovascular and neurodegenerative disease risk. When studying the effects of menopause in mice, modeled by ovariectomy, it is important to consider the effects of diet. Most standard rodent chows contain phytoestrogen-rich soybean meal, which can mimic the effects of estrogen. Understanding the impact of this soybean meal on outcomes is crucial to proper experimental design. Thus, the aim of this study was to compare the effects of standard and soy-free chows on cerebral artery endothelial function and cognitive function. We studied young female C57Bl/6J mice (n=43; ~6 months) divided into three groups: sham-controls on a soy-free diet (sham-SF), ovariectomized on a soy-free diet (OVX-SF), or OVX on a standard chow diet (OVX-SC). We assessed endothelium-dependent and -independent vasodilation in isolated pressurized posterior cerebral arteries (PCAs). We measured gene expression in cerebral arteries by real-time PCR. To assess behavioral function, we measured instinctual behavior via nest building. Data are presented as mean±SD. Compared with sham-SF, OVX-SF mice had impaired PCA endothelium-dependent vasodilation as evidenced by a maximal response that was 21% lower to acetylcholine (ACh, 60±14% vs. 47±14%, p=0.002) and 27% lower to insulin (52±17% vs. 38±8%, p=0.005). OVX-SC mice had a 27% greater PCA maximal vasodilation to insulin compared with OVX-SF mice (52±11% vs. 38±8%, p=0.001). The PCA responses to ACh and insulin did not differ between sham-SF and OVX-SC (p>0.05). Additionally, the PCA response to ACh and insulin in the presence of nitric oxide synthase inhibitor L-NAME did not differ between groups (p>0.05). Endothelium-independent vasodilation, measured as the PCA response to sodium nitroprusside, also did not differ between groups (p>0.05). There was a trend for lower gene expression of superoxide dismutase 2 ( Sod2) in cerebral arteries from OVX-SF mice (0.7±0.2 AU) compared with OVX-SC (1.0±0.4 AU, p=0.14) but this difference did not reach statistical significance. Cerebral artery gene expression was not different between groups for Esr1 (estrogen receptor α), Insr (insulin receptor), Slca2 (GLUT1), Sod1, or Sod3 (all p>0.05). Lastly, nest building scores were higher in the OVX-SC (4.3±0.5 AU) compared with sham-SF (3.2±1.2 AU, p=0.02) and OVX-SF (3.2±1.0 AU, p=0.04) mice. In summary, we found that ovariectomy impairs endothelial function in cerebral arteries by reducing nitric oxide bioavailability, but a diet containing soy mitigates these effects of ovariectomy. In addition, a diet containing soy leads to better instinctual nest-building behavior in mice. These findings highlight the importance of considering dietary soy when performing vascular and behavior tests in mice, particularly when interested in the effects of sex hormones. Luvaas Family Fund This is the full abstract presented at the American Physiology Summit 2023 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.

Impaired Endothelial Vasomotor Function with Borderline-High Triglycerides

Approximately 1 in 3 adults in the United States have a triglyceride (TG) concentration above 150 mg/dL and 1 in 5 adults have TG levels 200 mg/dL or higher. Moreover, the prevalence of suboptimal TGs (>150 mg/dL) has increased 5-fold in middle-aged and older adults over the last 3 decades. While much attention has focused on the cardiovascular effects of high and very high TG levels, where other lipid and metabolic abnormalities are often present, there are currently little data on the influence of borderline-high TG concentrations on vascular health. This represents a critical void in our understanding of the pathogenesis of cardiovascular disease (CVD) with TGs. Impaired endothelial vasomotor function is a central etiologic feature in the development of CVD and associated thrombotic events. We tested the hypothesis that endothelium-dependent vasomotor function is impaired in adults with borderline-high TG concentrations. Thirty-two sedentary, adults were studied: 15 (7M/8F, age: 56±1 yr; BMI: 26.8±0.6 kg/m2) with normal TG (35-140 mg/dL) and 17 (9M/8F, age: 57±1 yr; BMI: 28.7±0.8 kg/m2) with borderline-high TG (150-199 mg/dL) levels. Forearm blood flow (FBF; plethysmography) was determined in response to the intra-arterial infusion: acetylcholine (ACh) (4.0, 8.0, and 16.0 mg/100 mL tissue/min), sodium nitroprusside (1.0, 2.0, and 4.0 mg/100 mL tissue/min) and selective ETa receptor blocker (BQ-123, 100 nmol/min for 60 min). FBF response to ACh was significantly lower (~20%) in the borderline-high TG (from 4.7±0.3 to 11.6+0.6 mL/100 mL tissue/min) vs normal TG (from 4.3±0.3 to 14.6±0.5 mL/100 mL tissue/min) group. There were no significant group differences in the FBF responses to sodium nitroprusside. BQ-123 elicited a significant vasodilator response (~20%) in the borderline-high TG adults but did not alter FBF in the normal TG adults. Co-infusion of BQ-123 did not affect FBF responses to ACh in normal TG group but resulted in an ~30% increase in Ach-induced vasodilation (from 4.3±0.4 to 15.1±0.7 mL/100 mL tissue/min; P<0.05) in borderline-high TG group. Triglyceride levels were significantly and inversely associated with total FBF response to ACh (r=-0.63) and positively associated with the peak FBF response to BQ-123 (r=0.53; P<0.05). These results indicate that borderline-high TG concentrations are associated with diminished endothelium-dependent vasodilation and enhanced ET-1-mediated vasoconstrictor tone. Impaired endothelial vasomotor function may underlie the increased risk of CVD in adults with borderline-high TG levels. Nothing to disclose This is the full abstract presented at the American Physiology Summit 2023 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.

СЕРОСОДЕРЖАЩИЕ АМИНОКИСЛОТЫ И РИСК РАЗВИТИЯ АРТЕРИАЛЬНОЙ ГИПЕРТЕНЗИИ У ДЕТЕЙ

Introduction. Currently, sulfur-containing amino acids are potential candidates as risk factors for cardiovascular disease. The purpose: to establish the role of sulfur-containing amino acids and their derivatives in the risk of developing arterial hypertension in children. Matherial and methods. 111 children aged 14 to 18 years were examined. All patients were divided into 3 groups: the 1st group (n=51) consisted of children with arterial hypertension, the 2nd group (n=30) – with high normal blood pressure, the 3rd group – 30 healthy children. The content of sulfur-containing amino acids and their derivatives in blood plasma was determined by high-performance liquid chromatography. Result. The concentration of sulfur-containing amino acids methionine, homocysteine, cysteine and cysteinylglycine in the blood plasma of children with arterial hypertension tend to increase in comparison with the group of healthy children. Pathological decrease in endothelium-dependent vasodilation accompanied by an increase in the concentration of methionine, homocysteine, cysteine, cysteinylglycine, glutathione in blood plasma and a decrease – taurine. A prognostic model has been developed based on the determination of the concentration of homocysteine and cysteinylglycine in the blood plasma of children. With a calculated value of p≥0,44, makes it possible to predict a high probability of arterial hypertension with a sensitivity of 90,2%, a specificity of 66,7% and a diagnostic efficiency of 82,1%. Conclusions. The concentration of sulfur-containing amino acids methionine, homocysteine, cysteine and cysteinylglycine in the blood plasma of children with arterial hypertension tend to increase in comparison with the group of healthy children.

The Use of L-Arginine in Hypertension: An Educational Article and Expert Opinion

Background: Impairment of endothelium-dependent vasodilation has been increasingly recognized as an important contributor for the development of essential hypertension’s-arginine is an amino acid that is considered the biological precursor of nitric oxide which is an important contributor to microvascular vasodilation and to the reduction atherosclerosis. L-arginine has been recognized as safe (GRAS-status) when taken in an oral dose of up to 20 g daily. Patients and Methods: A 49-year male patient was recently found to be hypertensive on a routine check, and was advised to take an antihypertensive medication, but he requested treatment with health supplement initially to avoid the development of impotence attributed to antihypertensive medications. Results: The patient was recently found to be hypertensive on a routine check (Blood pressure: 160/110 mmHg), and was advised to take an antihypertensive medication, but he requested treatment with health supplement initially to avoid the development of impotence attributed to antihypertensive medications. The patient was treated with a unique approach under close supervision to avoid the development of hypertensive complication. He received oral l-arginine 3g daily before breakfast taken with lemon juice for its antioxidant vitamin C content. Within less than one week, his blood pressure normalized (Blood pressure: 135/85 mmHg). Conclusion: Oral L-arginine has been emerging as a new effective approach of reducing blood through improving endothelial function in hypertensive patients. This paper reports the successful treatment of hypertension with L-arginine.

Toll-like receptor 4 activation contributes to systemic vascular dysfunction in pregnant rats fed a high cholesterol diet during pregnancy

Background: Hypercholesterolemia is a hallmark clinical feature of cardiovascular diseases. Vascular adaptations to pregnancy include withstanding pregnancy-induced hypercholesterolemia, a physiological process required for fetus development. However, excessive (pathological) hypercholesterolemia during pregnancy has been linked to an increased risk of complications (e.g., preeclampsia); still, the underlying mechanisms are unclear. Toll-like receptor 4 (TLR4) is an innate immune receptor modulated by high cholesterol levels (in non-pregnant animals), but whether TLR4 activation also plays a role in vascular dysfunction in pregnancies complicated with hypercholesterolemia is unknown. Hypothesis: Pathological hypercholesterolemia during pregnancy causes maternal vascular dysfunction via activation of TLR4. Methods: Sprague Dawley rats were fed a standard (CD) or high cholesterol diet (HCD; 2% cholesterol and 0.5% cholic acid) from gestational day (GD) 6 to GD20 (term=22 days; n=9-10). Blood pressure was assessed before pregnancy and on GD19, and the results are presented as delta change. On GD20, body weight and pregnancy outcomes were recorded, and mesenteric arteries (systemic resistance arteries) were assessed using wire myography to evaluate vasoconstriction capacity to phenylephrine and endothelial-dependent vasodilation responses to methacholine. Experiments were conducted in the presence or absence of L-NAME (a pan-NOS inhibitor, 100 mmol/l) and/or CLI-095 (a TLR4 inhibitor, 10 mmol/l). Functional data were summarized as Emax (maximum response) or pEC50 (concentration required to produce 50% of Emax). Statistics: Student’s t-test or two-way ANOVA with Sidak post hoc test (significance: p<0.05). Results: The HCD prevented the late gestation systolic (p=0.0004) and diastolic (p=0.0066) blood pressure reduction observed in the CD group, and impaired male (p=0.0062) and female (p=0.0352) fetoplacental efficiency. Total body weight gain during pregnancy was not different between CD and HCD dams (p>0.05). In mesenteric arteries, vasoconstriction responses to phenylephrine (Emax) were increased in HCD dams (p=0.0056), and TLR4 inhibition with CLI-095 reduced the sensitivity (pEC50) of phenylephrine in these vessels (p=0.0147). Additionally, HCD dams presented higher sensitivity (pEC50) to methacholine (p=0.0169), which was not modified by the TLR4 inhibitor (p>0.05). Incubation of arteries with L-NAME abolished the increased sensitivity to methacholine (p>0.05), which was not further altered by CLI-095 (p>0.05). Conclusion: Inhibition of TLR4 ( ex vivo) reduced the enhanced vasoconstriction observed in HCD dams but did not alter endothelial-dependent vasodilation responses. Thus, if inhibiting TLR4 could block the vasoconstrictor effects of excessive hypercholesterolemia during pregnancy, this may be a target for future therapy development. This work was supported by a foundation grant from CIHR (FS154313) and by the generosity of the Stollery Children's Hospital Foundation and the Alberta Women's Health Foundation through the Women and Children's Health Research Institute (WCHRI). This is the full abstract presented at the American Physiology Summit 2023 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.

Abstract 484: Antidiabetic Agent, Canagliflozin, Is A Potent Vasodilator Of The Coronary Microvasculature

Objective: Sodium-glucose cotransporter-2 (SGLT-2) inhibitors are cardioprotective even in the absence of preexisting diabetic microvascular disease. Our group has shown SGLT-2 inhibitor, canagliflozin, increases myocardial perfusion without an attendant increase in angiogenesis. We hypothesize canagliflozin accentuates vasodilation of coronary microvasculature to increase perfusion. Methods: Coronary resistance arterioles (174 ± 60μm in diameter) isolated from Sprague-Dawley rats either receiving daily canagliflozin (15mg/kg, oral gavage) for four weeks (n = 4) or no treatment (n = 4) were studied in vitro in a pressurized (40mmHg), no-flow state using video microscopy. Following preconstriction of microvessels with thromboxane analog U46619 or endothelin-1, concentration response curves to vasodilatory adenosine 5’-diphosphate (ADP), acetylcholine (ACh), and sodium nitroprusside (SNP) were completed. Additionally, nitric-oxide-dependent ADP-induced vasodilation of microvessels isolated from treated rats was measured in the presence of N ω -Nitro-L-arginine methyl ester (L-NAME) 10μM. Results: Canagliflozin treatment was associated with a significant increase in endothelium-dependent vasodilatory response to ADP (p = 0.039) (Figure 1). Pretreatment with L-NAME, an inhibitor of nitric oxide synthase, eliminated this vasodilatory response. Compared to ADP, vasodilatory response to ACh was muted (p = 0.552). Endothelium-independent vasodilatory response to SNP, a nitric oxide donor, strongly trended toward an increase in the treated group (p = 0.099). Conclusions: Canagliflozin improves microvascular vasodilation in an endothelium-dependent and endothelium-independent fashion not yet described. These findings implicate both vascular endothelium and arteriolar smooth muscle cells in altered vasomotor physiology and may, in part, account for the observed increase in myocardial blood flow with canagliflozin treatment.

Endothelial dysfunction in the pathogenesis of arterial hypertension: new diagnostic methods

ENDOTHELIAL DYSFUNCTION IN THE PATHOGENESIS OF ARTERIAL HYPERTENSION: NEW DIAGNOSTIC METHODS Tetiana V. Talaieva State Institution «National Scientific Center «M. D. Strazhesko Institute of Cardiology, Clinical and Regenerative Medicine of the National Academy of Medical Sciences of Ukraine», 5, Svyatoslava Khorobroho Str., Kyiv, Ukraine 03151 Introduction. Arterial hypertension (AH) remains the most widespread disease of the circulatory system, as well as one of the leading risk factors for the development of cardiovascular diseases. Recent studies indicate that endothelial dysfunction may play a key role in the pathogenesis of hypertension. Endothelial dysfunction is associated with damage and accelerated apoptosis of endothelial cells (ECs), and quite often these changes occur before morphological and clinical signs of the disease appear. The researches of the last decades established that the most important properties of the endothelium - restoration and preservation of structural and functional integrity and its reparative activity are directly related to circulating endothelial progenitor cells - precursor cells of endotheliocytes (ECCs). The use of various markers for the determination of ECCs in circulating blood, the determination of the content of exfoliated endothelial cells and the reserve function of the bone marrow (ability to produce ECCs) makes it possible to assess the function of the endothelium and the risk of the development and progression of cardiovascular diseases. Purpose: using the flow cytometry method to evaluate the possibility of determining the content of ECCs in the blood, desquamated ECs and the reserve function of the bone marrow (ability to produce ECCs) as markers of endothelial dysfunction. Materials and methods. 153 patients with AH were included in the study. All patients underwent complaint registration, history taking, general clinical examination, including office blood pressure measurement and daily blood pressure monitoring, physical examination, brachial artery compression test to assess endothelium-dependent vasodilatation. The number of ECCs of peripheral blood was determined by the method of flow cytometry with the help of reagents for the determination of differentiation clusters CD34, CD45, CD31, CD133 manufactured by "Beckman Coulter Inc.". In the conditions of the test with dosed physical load, the blood content of ECCs was determined on a bicycle ergometer before and after 60 minutes. after completing the test on 55 patients with hypertension. The results. In the studies, complex determination of various markers on the surface of the ECCs was used. At baseline, the number of ECCs (CD34+/CD45-/+) was 22 % lower in patients with hypertension, and 28 % lower in patients with resistant hypertension than in practically healthy donors (р < 0.05). The number of ECCs (CD133+ CD31+ CD45-/+) in patients with hypertension was 25 % less than in the norm. The number of desquamated cells exceeded the norm by 152 % (р < 0.001). In patients with hypertension, there was a decrease in the reserve function of the bone marrow to produce ECCs in response to ischemia caused by stress. The obtained data are confirmed by the results of the brachial artery compression test. Based on the results of the analysis in the groups with controlled and resistant hypertension, it was found that the last index of EDVD was 25 % lower than in the group of patients with hypertension that is well controlled (р < 0.05). The use of standard therapy for 12 weeks was accompanied by an increase in the number of ECCs in patients, which indicated the restoration of endothelial function after the treatment. Conclusions. In patients with hypertension, a decrease in the content of ECCs in the blood was noted. The resistant course of hypertension is associated with greater manifestations of endothelial dysfunction. Determination of ECCs using the flow cytometry method provides important additional information about endothelial dysfunction as a risk factor for the development and progression of hypertension, and can also be used to assess the effectiveness of antihypertensive therapy. Keywords: arterial hypertension, endothelium, dysfunction, endothelial progenitor cells.

The efficacy of sodium ferulate combination therapy in coronary heart disease: A systematic review and meta-analysis

BackgroundSodium ferulate (SF), a derivative of ferulic acid, is one of the active constituents in medicinal plants thought to be useful in fighting cardiovascular diseases. However, there still lacks a systematic review of the efficacy and safety of SF in treating coronary heart disease (CHD). It is therefore the purpose of this study to comprehensively review all clinical randomized controlled trials (RCTs) of SF in CHD to assess its efficacy and safety. MethodsAll analysis is based on 8 databases as of February 2023, which includes 35 outcomes of RCTs that investigate the effect of SF combination therapy in CHD. The present study evaluates the quality and bias of selected literature by the Jadad scale and Cochrane Collaboration's tools, and also the quality of evidence by GRADE Profiler. Furthermore, it applies sensitivity analysis to assess the high heterogeneity impact of outcomes and conducted subgroup analysis to estimate the influence factors in these studies. The study protocol was set documented, and published beforehand in PROSPERO (Registration No.CRD42022348841). ResultsThe meta-analysis of 36 studies (with 3207 patients) shows that SF combined with conventional drugs has improved clinical effectiveness for patients with CHD [RR: 1.21 (95% CI 1.17,1.26); p < 0.00001]. Statistically significant results of meta-analyses are also seen in electrocardiography (ECG) efficacy, frequency of angina attacks, endothelium-dependent flow-mediated vasodilation (FMD), nitric oxide (NO), endothelin (ET), whole Blood low shear rate (LS), platelet aggregation test (PAgT), C-reactive protein (CRP), tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL6), triglyceride (TG). Adverse events are reported in 6 RCTs. By GRADE approaches, 2 outcomes (clinical efficacy, CRP) indicate a moderate quality of evidence, 17 outcomes indicate low quality of evidence, with the other 16 very low-quality. ConclusionSF combination therapy has a better curative effect than conventional therapy. However, due to items with low-quality evidence demonstrated in the study, the presence of clinical heterogeneity, and imprecision in partial outcome measures, all these led to limitations in the evidence of this study. Thus, the conclusion needs to be further verified by more in-depth research.

Exercise protects aged mice against coronary endothelial senescence via FUNDC1-dependent mitophagy

Vascular aging contributes to adverse changes in organ function and is a significant indicator of major cardiac events. Endothelial cells (ECs) participate in aging-provoked coronary vascular pathology. Regular exercise is associated with preservation of arterial function with aging in humans. However, the molecular basis is not well understood. The present study was aimed to determine the effects of exercise on coronary endothelial senescence and whether mitochondrial clearance regulator FUN14 domain containing 1 (FUNDC1)-related mitophagy and mitochondrial homeostasis were involved. In mouse coronary arteries, FUNDC1 levels showed gradually decrease with age. Both FUNDC1 and mitophagy levels in cardiac microvascular endothelial cells (CMECs) were significantly reduced in aged mice and were rescued by exercise training. Exercise also alleviated CMECs senescence as evidenced by senescence associated β-galactosidase activity and aging markers, prevented endothelial abnormal cell migration, proliferation, and eNOS activation in CMECs from aged mice, and improved endothelium-dependent vasodilation of coronary artery, reduced myocardial neutrophil infiltration and inflammatory cytokines evoked by MI/R, restored angiogenesis and consequently alleviated MI/R injury in aging. Importantly, FUNDC1 deletion abolished the protective roles of exercise and FUNDC1 overexpression in ECs with adeno-associated virus (AAV) reversed endothelial senescence and prevented MI/R injury. Mechanistically, PPARγ played an important role in regulating FUNDC1 expressions in endothelium under exercise-induced laminar shear stress. In conclusion, exercise prevents endothelial senescence in coronary arteries via increasing FUNDC1 in a PPARγ-dependent manner, and subsequently protects aged mice against MI/R injury. These findings highlight FUNDC1-mediated mitophagy as potential therapeutic target that prevents endothelial senescence and myocardial vulnerability.

Lipid-lowering therapy in patients with arterial hypertension with concomitant chronic obstructive pulmonary disease

Оbjective: in order to evaluate the effects (lipid-lowering, the effect on the endothelial function and oxidative stress) of pitavastatin at a dose of 4 mg in patients with dyslipidemia, arterial hypertension (AH) and chronic obstructive pulmonary disease (COPD) at baseline, after 4 weeks and 12 months of treatment. Material and methods: the prospective study included 33 patients (mean age 60 [54;61] years) with AH, COPD and dyslipidemia. Laboratory examination consisted in determining the lipid spectrum, the level of lipid peroxidation products, creatinine, bilirubin, alanine aminotransferase, aspartate aminotransferase. The endothelium’s function was performed by the test with the endothelium-dependent vasodilation. We prescribed Pitavastatin (4 mg, Livazo, Recordati, Ireland) as a lipid-lowering therapy. After 12 months, the atherosclerotic plaques (AP) in the vessel was seen by the ultrasound duplex scanning of carotid arteries. Results: after 4 weeks of treatment with pitavastatin (4 mg), there was a decrease in total cholesterol — 26%, low-density lipoprotein (LDL) — 33%, triglycerides (TG) — 19%, high-density lipoprotein was increased by 18%. There was an improvement in endothelial dysfunction and oxidative stress. There were no side effects in patients. Conclusion: correction of lipid metabolism disorders in AH patients with COPD by prescribing pitavastatin (4 mg) can reduce total cholesterol, LDL and TG, can positively affect endothelial function and lipid peroxidation processes. Therapy with pitavastatin (4 mg) in patients with dyslipidemia, AH and COPD is safe. It is noted the regression of AP after 12 months of regular intake of pitavastatin at a dose of 4 mg.

Impaired β 2 -adrenergic endothelium-dependent vasodilation in patients previously hospitalized with coronavirus disease 2019.

The pulse wave response to salbutamol (PWRS) - change in augmentation index (AIx) - provides a means to assess endothelial vasodilator function in vivo . Endothelial dysfunction plays a relevant role in the pathogenesis of hypertension and cardiovascular disease and appears to underlie many of the complications of coronavirus disease 2019 (COVID-19). However, to what degree this persists after recovery is unknown. Individuals previously hospitalized with COVID-19, those recovered from mild symptoms and seronegative controls with well known risk factors for endothelial dysfunction were studied. To assess the involvement of nitric oxide-cyclic guanosine monophosphate pathway (NO-cGMP) on PWRS, sildenafil was also administrated in a subsample. One hundred and one participants (60 men) aged 47.8 ± 14.1 (mean ± SD) years of whom 33 were previously hospitalized with COVID-19 were recruited. Salbutamol had minimal effect on haemodynamics including blood pressure and heart rate. It reduced AIx in controls ( n = 34) and those recovered from mild symptoms of COVID-19 ( n = 34) but produced an increase in AIx in those previously hospitalized: mean change [95% confidence interval] -2.85 [-5.52, -0.188] %, -2.32 [-5.17,0.54] %, and 3.03 [0.06, 6.00] % for controls, those recovered from mild symptoms and those previously hospitalized, respectively ( P = 0.001). In a sub-sample ( n = 22), sildenafil enhanced PWRS (change in AIx 0.05 [-2.15,2.24] vs. -3.96 [-7.01. -2.18], P = 0.006) with no significant difference between hospitalized ( n = 12) and nonhospitalized participants ( n = 10). In patients previously hospitalized with COVID-19, there is long-lasting impairment of endothelial function as measured by the salbutamol-induced stimulation of the NO-cGMP pathway that may contribute to cardiovascular complications.

Aerobic exercise training reduces ET-1-mediated vasoconstriction and improves endothelium-dependent vasodilation in postmenopausal women.

Endothelin-1 (ET-1) contributes to vascular dysfunction in postmenopausal women (PMW). Although aerobic exercise is beneficial in reducing ET-1-mediated vasoconstrictor tone in men, it is unknown whether this favorable vascular effect occurs in women. We tested the hypothesis that aerobic exercise training reduces ET-1-mediated vasoconstriction in PMW. We further hypothesized that reductions in ET-1 vasoconstrictor tone underly exercise-induced improvements in endothelium-dependent vasodilatation in PMW. Forearm blood flow (FBF) responses to intra-arterial infusion of selective ETA receptor blockade (BQ-123, 100 nmol/min for 60 min) and acetylcholine (4.0, 8.0, and 16.0 μg/100 mL tissue/min) in the absence and presence of ETA receptor blockade were determined before and after a 12-wk aerobic exercise training intervention in 18 healthy, sedentary PMW (58 ± 4 yr). Women exercised an average of 4.9 ± 0.7 day/wk for 51 ± 7 min/day at 71 ± 3% of maximal heart rate. Before exercise, BQ-123 significantly increased FBF (∼25%) in sedentary PMW; however, this effect was abolished following the exercise intervention. FBF responses to acetylcholine were also significantly higher after exercise training (from 4.2 ± 1.2 to 14.0 ± 3.8 mL/100 mL tissue/min) versus before (from 4.1 ± 1.0 to 11.4 ± 3.3 mL/100 mL tissue/min; ∼25% increase; P < 0.05). Before exercise training, coinfusion of BQ-123 with acetylcholine enhanced (∼25%; P < 0.05) the vasodilator response (from 4.4 ± 1.1 to 13.9 ± 4.2 mL/100 mL tissue/min) compared with acetylcholine alone; after exercise training, the presence of BQ-123 did not significantly affect the vasodilator response to acetylcholine. Aerobic exercise training reduces ET-1-mediated vasoconstriction in PMW. Furthermore, decreased ET-1-mediated vasoconstriction is an important mechanism underlying aerobic exercise-induced improvement in endothelium-dependent vasodilation in PMW.NEW & NOTEWORTHY Endothelin-1 (ET-1) contributes to declines in endothelial function in postmenopausal women. To our knowledge, we show for the first time that aerobic exercise reduces ET-1-mediated vasoconstriction in previously sedentary postmenopausal women. Moreover, aerobic exercise improved endothelial-dependent dilation due in part to the reductions in ET-1-mediated vasoconstriction.

Endothelial cell vasodilator dysfunction mediates progressive pregnancy-induced hypertension in endothelial cell tetrahydrobiopterin deficient mice

Background and purposePregnancy-associated vascular remodelling is essential for both maternal and fetal health. We have previously shown that maternal endothelial cell tetrahydrobiopterin (BH4) deficiency causes poor pregnancy outcomes. Here, we investigated the role and mechanisms of endothelial cell-mediated vasorelaxation function in these outcomes. Experimental approachThe vascular reactivity of mouse aortas and uterine arteries from non-pregnant and pregnant endothelial cell-specific BH4 deficient mice (Gch1fl/flTie2cre mice) was assessed by wire myography. Systolic blood pressure was assessed by tail cuff plethysmography. Key resultsIn late pregnancy, systolic blood pressure was significantly higher (∼24 mmHg) in Gch1fl/flTie2cre mice compared with wild-type littermates. This was accompanied by enhanced vasoconstriction and reduced endothelial-dependent vasodilation in both aorta and uterine arteries from pregnant Gch1fl/flTie2cre mice. In uterine arteries loss of eNOS-derived vasodilators was partially compensated by upregulation of intermediate and large-conductance Ca2+-activated K+ channels. In rescue experiments, oral BH4 supplementation alone did not rescue vascular dysfunction and pregnancy-induced hypertension in Gch1fl/flTie2cre mice. However, combination with the fully reduced folate, 5-methyltetrahydrofolate (5-MTHF), restored endothelial cell vasodilator function and blood pressure. Conclusions and implicationsWe identify a critical requirement for maternal endothelial cell Gch1/BH4 biosynthesis in endothelial cell vasodilator function in pregnancy. Targeting vascular Gch1 and BH4 biosynthesis with reduced folates may provide a novel therapeutic target for the prevention and treatment of pregnancy-related hypertension.

Interrelation between the parameters of endogenous vascular regulation, oxidative stress and the markers of inflammatory response in COVID-19 patients while on extracorporeal membrane oxygenation

Introduction. Extracorporeal membrane oxygenation has found wide application in clinical practice during the COVID-19 pandemic. Oxidative stress, endothelial dysfunction, and systemic inflammatory response syndrome play an important role in the pathogenesis of COVID-19. Our research was designed to study correlations in-between those factors and the impact of extracorporeal membrane oxygenation on them.Aim. The study of systemic inflammatory response and endothelial function in patients with COVID-19 during extracorporeal membrane oxygenation.Material and methods. In the course of a prospective study, we examined 100 COVID-19 patients aged 26 to 75 years, median 55 years [47;60], who were treated at the N.V. Sklifosovsky Research Institute for Emergency Medicine, using extracorporeal membrane oxygenation. As a control group (normal), 25 practically healthy people whose median age was 32 years [25;39] were examined. The function of the vascular endothelium was assessed by the content of nitric oxide stable metabolites in the blood serum and the level of angiotensin-converting enzyme. Next, the ratio of nitric oxide metabolite to angiotensin-converting enzyme level was calculated, reflecting the imbalance between endotheliumdependent vasodilation and vasoconstriction. To assess the severity of oxidative stress in blood serum, malondialdehyde was determined as a marker of lipid peroxidation. The state of the antioxidant system was assessed in terms of total antioxidant status of blood serum. The presence of an imbalance in the system of lipid peroxidation and the antioxidant system total antioxidant status was judged by the oxidative stress coefficient, i.e. the ratio of malondialdehyde to the total antioxidant activity.Results. The analysis showed the presence and progression of endothelial dysfunction, impaired vascular regulation, activation of free radical processes, the presence of an imbalance in the prooxidant/antioxidant system, as well as the progression of the inflammatory process with a decrease in the level of markers of the COVID-19 severity.Conclusion. Further studies of the correlation between endothelial damage and the severity of the systemic inflammatory response syndrome may be of fundamental importance for explaining the pathophysiological mechanisms of COVID-19 course and developing new treatments for such patients.

The Role of Rehabilitation in Arterial Function Properties of Convalescent COVID-19 Patients.

Coronavirus disease (COVID-19) is a respiratory disease, although arterial function involvement has been documented. We assess the impact of a post-acute COVID-19 rehabilitation program on endothelium-dependent vasodilation and arterial wall properties. We enrolled 60 convalescent patients from COVID-19 and one-month post-acute disease, who were randomized at a 1:1 ratio in a 3-month cardiopulmonary rehabilitation program (study group) or not (control group). Endothelium-dependent vasodilation was evaluated by flow-mediated dilation (FMD), and arterial wall properties were evaluated by carotid-femoral pulse wave velocity (cf-PWV) and augmentation index (AIx) at 1 month and at 4 months post-acute disease. FMD was significantly improved in both the study (6.2 ± 1.8% vs. 8.6 ± 2.4%, p < 0.001) and control groups (5.9 ± 2.2% vs. 6.6 ± 1.8%, p = 0.009), but the improvement was significantly higher in the study group (rehabilitation) (p < 0.001). PWV was improved in the study group (8.2 ± 1.3 m/s vs. 6.6 ± 1.0 m/s, p < 0.001) but not in the control group (8.9 ± 1.8 m/s vs. 8.8 ± 1.9 m/s, p = 0.74). Similarly, AIx was improved in the study group (25.9 ± 9.8% vs. 21.1 ± 9.3%, p < 0.001) but not in the control group (27.6 ± 9.2% vs. 26.2 ± 9.8 m/s, p = 0.15). Convalescent COVID-19 subjects of the study group (rehabilitation) with increased serum levels of circulating IL-6 had a greater reduction in FMD. Conclusively, a 3-month cardiopulmonary post-acute COVID-19 rehabilitation program improves recovery of endothelium-dependent vasodilation and arteriosclerosis.

Influence of nitro ruthenium isomerization on photochemically induced nitric oxide release: Vasorelaxant activities

We have synthesized cis-[Ru(bpy)2(NO2-κN)Ln-](n-1) and cis-[Ru(bpy)2(NO2-κO)L n-](n-1) (bpy = 2,2′-bipyridine; k = indication of the coordinated center to Ruthenium; L = pyridine type ligand) by reacting cis-[Ru(bpy)2(H2O)Ln-](n-2) with sodium nitrite or conducting basic cis-[Ru(bpy)2NO(Ln-)](n-3) hydrolysis. Photolysis at the metal-ligand charge transfer band (MLCT) of the isomers yielded nitric oxide (NO) as determined by NO measurement. The NO photorelease rates obtained upon 447 nm laser irradiation of the ruthenium complexes showed that cis-[Ru(bpy)2(NO2-κO)Ln-](n-1) released NO three times faster than cis-[Ru(bpy)2(NO2-κN)Ln-](n-1). We investigated endothelium-dependent vasodilation induced by cis-[Ru(bpy)2(4-pic)(NO2-κN)]+ and cis-[Ru(bpy)2(4-pic)(NO2-κO)]+ (4-pic = 4-picoline) in isolated 3 mm aortic rings precontracted with L-phenylephrine. Maximum vasodilation was achieved under 447 nm laser irradiation of 0.5 μMol.L−1 ruthenium complexes for 100 s.