Endothelium-dependent Vasodilation Research Articles

Rosa damascena Miller essential oil relaxes rat thoracic aorta through the NO-cGMP-dependent pathway

AimThis study aimed to investigate the effects of Rosa damascena Mill. essential oil on the vascular activity of rat thoracic aorta and its underlying mechanisms. MethodsExperiments were performed using the isolated tissue bath model and Wistar rats. 0.1, 1, 10, and 100 µg/mL concentrations of rose oil were administered in all groups. To determine the vasoactive effects of rose oil, submaximal contractions were conducted by applying 10−5 M PE and 45 mM KCl separately in both endothelium-intact and -denuded segments. Time-matched distilled water groups were formed for control. To evaluate the role of endothelium-derived vasodilative factors, endothelium-intact segments were incubated with nitric oxide synthase inhibitor L-NAME, soluble guanylate cyclase inhibitor ODQ, and a non-selective cyclooxygenase inhibitor INDO. The statistical significance level was considered as p < 0.05. Results1, 10, and 100 µg/mL rose oil doses led to vasorelaxation in thoracic aortas precontracted with 10−5 M PE (p: 0.029, p: 0.000, p: 0.000, respectively). In precontracted thoracic aortas with 45 mM KCl, the significant effect of rose oil persisted, albeit slightly diminished. When the endothelium was removed, the relaxant effect of rose oil was partially reduced, but still significant (p: 0.035, p: 0.028, p: 0.000, respectively). Preincubations with L-NAME and ODQ significantly attenuated rose oil-induced relaxation of endothelium-intact aortas precontracted with 10−5 M PE. In contrast, preincubation INDO did not modulate rose oil-induced relaxation. ConclusionIn conclusion, it was shown for the first time that rose oil can significantly mediate vasorelaxation in both PE and KCl precontracted rat thoracic aortas. Rose oil induced vasodilation with or without endothelium in a concentration-dependent manner. It was also shown that rose oil-induced vasorelaxant effects were reduced by L-NAME or ODQ pretreatment, but not modulated by INDO. These results demonstrated that rose oil-induced endothelium-dependent vasodilation is mediated by the NO-cGMP-dependent pathway.

Endothelial Microparticles as Potential Biomarkers in the Assessment of Endothelial Dysfunction in Hypercholesterolemia.

Background and Objectives: Endothelial microparticles (EMP) particularly CD31+/42−/AV+, CD144+/AV+ and CD62e+/AV+ have been reported as having increased in cardiovascular-related diseases, making them potential biomarkers for endothelial dysfunction. This study aimed to compare these EMPs in patients with hypercholesterolemia and healthy controls and to correlate their levels with endothelium-dependent vasodilation (EDV) assessed via pulse wave analysis (PWA); an established method of assessing endothelial function. Materials and Methods: EMPs from 88 subjects (44 hypercholesterolemia patients and 44 controls) were quantified from whole blood using flow cytometry analysis. Endothelial function was determined using PWA combined with pharmacological challenge. Results: CD31+/42−/AV+ (3.45 ± 4.74 count/µL vs. 1.33 ± 4.40 count/µL; p = 0.03), CD144+/AV+ (7.37 ± 12.66 count/µL vs. 1.42 ± 1.71 count/µL; p = 0.003) and CD62e+/AV+ (57.16 ± 56.22 count/µL vs. 20.78 ± 11.04 count/µL; p < 0.001) were significantly elevated in the hypercholesterolemic group compared with the controls, respectively. There was a significant inverse moderate correlation between all circulating EMPs and EDV: CD31+/42−/AV+ (r = −0.36, p = 0.001), CD144+/AV+ (r = −0.37, p = 0.001) and CD62e+/AV+ (r = −0.35, p = 0.002). Conclusions: All EMPs were raised in the patients with hypercholesterolemia, and these values correlated with the established method of assessing endothelial function.

Peripheral endothelial and microvascular damage in liver cirrhosis: A systematic review and meta‐analysis

This is the first systematic review and meta-analysis of studies using any available functional method to examine differences in peripheral endothelial function between cirrhotic and non-cirrhotic individuals. Literature search involved PubMed, Web-of-Science, and Scopus databases, as well as gray literature sources. We included studies in adult subjects evaluating endothelial function with any semi-invasive or non-invasive functional method in patients with and without liver cirrhosis. From 3378 records initially retrieved, 15 studies with a total of 570 participants were included in the final quantitative meta-analysis. In six studies examining endothelial function with flow-mediated-dilatation, no differences between patients with cirrhosis and controls were evident (WMD: 1.33, 95%CI [-2.87, 5.53], I2 = 97%, p < .00001). Among studies assessing differences in endothelial-dependent or endothelial-independent vasodilation with venous-occlusion-plethysmography, there were no significant differences between the two groups. When pooling all studies together, regardless of the technique used, no significant difference in endothelial function between cirrhotic patients and controls was observed(SMD: 0.79, 95%CI[-0.04, 1.63], I2 =94%, p < .00001). No differences in peripheral endothelial function assessed with semi-invasive or non-invasive functional methods exist between cirrhotic and non-cirrhotic subjects. The increasing co-existence of cardiovascular risk factors leading to impaired vascular reactivity in cirrhotic patients may partly explain these findings.

Th17 cell-linked mechanisms mediate vascular dysfunction induced by testosterone in a mouse model of gender-affirming hormone therapy.

Clinical data point to adverse cardiovascular events elicited by testosterone replacement therapy. Testosterone is the main hormone used in gender-affirming hormone therapy (GAHT) by transmasculine people. However, the cardiovascular impact of testosterone in experimental models of GAHT remains unknown. Sex hormones modulate T-cell activation, and immune mechanisms contribute to cardiovascular risk. The present study evaluated whether testosterone negatively impacts female cardiovascular function by enhancing Th17 cell-linked effector mechanisms. Female (8 wk old) C57BL/6J mice received testosterone (48 mg/kg/wk) for 8 wk. Male mice were used for phenotypical comparisons. The hormone treatment in female mice increased circulating testosterone to levels observed in male mice. Testosterone increased lean body mass and body mass index, and decreased perigonadal fat mass, mimicking clinical findings. After 8 wk, testosterone decreased endothelium-dependent vasodilation and increased peripheral Th17 cells. After 24 wk, testosterone increased blood pressure in female mice. Ovariectomy did not intensify phenotypical or cardiovascular effects by testosterone. Female mice lacking T and B cells [Rag1 knockout (-/-)], as well as female mice lacking IL-17 receptor (IL-17Ra-/-), did not exhibit vascular dysfunction induced by testosterone. Testosterone impaired endothelium-dependent vasodilation in female mice lacking γδ T cells, similarly to the observed in wild-type female mice. Adoptive transfer of CD4+ T cells restored testosterone-induced vascular dysfunction in Rag1-/- female mice. Together, these data suggest that CD4+ T cells, most likely Th17 cells, are central to vascular dysfunction induced by testosterone in female mice, indicating that changes in immune-cell balance are important in the GAHT in transmasculine people.NEW & NOTEWORTHY Sex hormone-induced cardiovascular events are important undesirable effects in transgender people under GAHT. Studies addressing the cardiovascular impact of GAHT will certainly contribute to improve healthcare services offered to this population. Our study showing that vascular dysfunction, via Th17 cell-related mechanisms, precedes increased blood pressure induced by testosterone in a GAHT mouse model, reveals potential mechanisms involved in GAHT-related cardiovascular events and may provide new markers/targets for clinical practices in transmasculine people.

Stimulation of the endogenous hydrogen sulfide synthesis restores constitutive nitric oxide synthesis and endothelium-dependent vasodilation in old rats

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Hydrogen sulfide (H2S) is a gas transmitter of endogenous origin, which has an important regulatory function in the human body. Endogenous H2S is synthesized by three enzymes, cistationine-β-synthase (CBS), cistationine-γ-liase (CSE), and 3-mercaptopyruvate sulfurtransferase (3-MTS), which is coupled to the activity of cysteine aminotransferase (CAT). CAT, CBS, and CSE are pyridoxal-5- phosphate (PLP)-dependent enzymes. It is known that with age the exchange of hydrogen sulfide is disturbed against the background of increasing oxidative and nitrosative stress. At the same time there is a decrease of constitutive synthesis of nitric oxide (NO). Recent studies show that hydrogen sulfide closely interacts with the NO system. Activation of H2S biosynthesis and restoration of its pools in tissues of old animals may be a promising direction of cardiovascular disease prevention. The aim of the current work was to study the effect of H2S-synthesizing enzymes cofactor pyridoxal-5-phosphate (PLP) on the endothelium-dependent relaxation of smooth muscle vessels in old rats, as well as the H2S content and cNOS activity in aortic tissues. Methods Old rats (22-24 months old) were PLP administered per os in dose of 0,7 mg per kg daily for 2 weeks.The content of hydrogen sulfide, activity of cNOS and iNOS was measured in aortic tissues.Vascular reactions were determined in experiments on isolated aortic strips. To clarify the role of either NO or H2S in the endothelium-dependent vasorelaxation, N-nitro-L-arginine methyl ester hydrochloride (L-NAME) (Sigma, USA, 27 mg/kg) or O-carboxymethylhydroxylamine (O-CMH) (50 mg/kg) (Sigma, USA) was injected intraperitoneally 30 min before sacrificing. Results We showed that the H2S content was 1.6 times lower in old rat aorta compared to adult ones. PLP administration for 2 weeks induced a significant increase of H2S content in aortic tissue of old rats (P&amp;lt;0.05). It was found that with aging, the activity of cNOS decreases by 3 times, and the stimulation of endogenous Н2S leads to an increase in the activity of this enzyme in the aortic tissues by 2.1 times as compared with those in old animals. At the same time, the activity of the iNOS enzyme with aging increases by 3.8 times, and after the introduction of PLP, it decreases almost halved. Also shown, that PLP significantly improved endothelium-dependent aortic smooth muscle relaxation in old rats. The amplitude of acetylcholine-induced relaxation which was significantly reduced in old rats was increased more than 2.5-fold. This effect was reversed by inhibitors of NO-synthase and 3-mercaptopyruvate sulfurtransferase indicating the involvement of NO and H2S in the improved endothelium-dependent vascular relaxation. Conclusions Thus, H2S acts as a regulator of the NO system that increases cNOS activity and NO synthesis in aortic tissue, which improves endothelium-dependent relaxation of aortic smooth muscle in aged rats.

Activation of AMPK/miR-181b Axis Alleviates Endothelial Dysfunction and Vascular Inflammation in Diabetic Mice.

Hyperglycemia in diabetes mellitus impairs endothelial function and disrupts microRNA (miRNA) profiles in vasculature, increasing the risk of diabetes-associated complications, including coronary artery disease, diabetic retinopathy, and diabetic nephropathy. miR-181b was previously reported to be an anti-inflammatory mediator in vasculature against atherosclerosis. The current study aimed to investigate whether miR-181b ameliorates diabetes-associated endothelial dysfunction, and to identify potential molecular mechanisms and upstream inducer of miR-181b. We found that miR-181b level was decreased in renal arteries of diabetic patients and in advanced glycation end products (AGEs)-treated renal arteries of non-diabetic patients. Transfection of miR-181b mimics improved endothelium-dependent vasodilation in aortas of high fat diet (HFD)/streptozotocin (STZ)-induced diabetic mice, accompanied by suppression of superoxide overproduction and vascular inflammation markers. AMPK activator-induced AMPK activation upregulated miR-181b level in human umbilical vein endothelial cells (HUVECs). Chronic exercise, potentially through increased blood flow, activated AMPK/miR-181b axis in aortas of diabetic mice. Exposure to laminar shear stress upregulated miR-181b expression in HUVECs. Overall, our findings highlight a critical role of AMPK/miR-181b axis and extend the benefits of chronic exercise in counteracting diabetes-associated endothelial dysfunction.

In vitro and ex vivo antioxidant and vasodilatory properties of Syzygium cumini, Piper sarmentosum roxB and Psidium guajava plant extracts from Reunion Island

Ischemic heart disease is the leading cause of cardiovascular death. It may originate from large vessel obstruction or from coronary microvascular dysfunction (CMD). CMD is associated with oxidative stress, which induces endothelial dysfunction and therefore alters vasodilation. The potentially beneficial cardiovascular effects of plant extracts have long been suggested by traditional medicine. We investigated the antioxidant and vasodilatory potential of 5 extracts from 3 plants from Reunion Island on in vitro and ex vivo experimental models. Aqueous extracts (AE) of Piper sarmentosum roxB (PSR) roots, PSR leaves, Psidium guajava (PG) leaves, a methanolic extract (ME) of Syzygium cumini (SC) seeds, and a hydroalcoholic extract (HE) of SC fruits were obtained. Their antioxidant capacities were assessed using DPPH (2,2DiPhenyle-1-Picryl-Hydrazyle). Concentrations of extracts ranged from 5 to 40 μg/mL in order to determine EC50 and T-EC50 values. To assess the vasodilatory potential of the extracts, phenylephrine-precontracted aortic rings from male Sprague Dawley rats with > 60% endothelium-dependent vasodilation were incubated with the extracts (50 μg/mL). Extracts displaying a vasodilatory effect were then used at 0.5, 5, and 50 μg/mL on precontracted aortic rings with (> 60%) or without (< 10%) endothelium. Finally, the pathway involved in endothelium-dependent relaxation by the extract was investigated by preincubation with the nitric oxide synthase (NOS) inhibitor L-NAME. The results are presenting in Table 1 . A high antioxidant capacity was observed for SC seed ME (EC50 = 8.0 μg/mL; T-EC50 = 10 min) and PG AE (EC50 = 9.7 μg/mL; T-EC50 = 15 min). SC seed ME and PG AE also demonstrated a vasodilatory effect (respectively: 64 ± 12% and 55 ± 17% vs. 4 ± 9% for control, P < 0.0001). No vasodilation was observed following endothelium removal. L-NAME significantly inhibited the vasodilatory effect of SC seed ME (32 ± 19% vs. 67 ± 15%, P = 0.003), but not that of PG (38 ± 19% vs. 66 ± 30%, P = 0.7). SC seed and PG demonstrated promising potential to prevent CMD due to their antioxidant properties and endothelium-dependent vasodilatory effects, with the effect of SC seed effect involving endothelial NOS. Further studies are warranted to determine the in vivo potential of these extracts.

FUNCTIONAL FOOD ENRICHED IN N-3 POLYUNSATURATED FATTY ACIDS, SELENIUM, LUTEIN AND VITAMIN E ENHANCES MICROVASCULAR ENDOTHELIAL FUNCTION OF COMPETITIVE ATHLETES

Objective: A substantial proportion of competitive athletes do not reach dietary goals for various macro- and micronutrients, important in creating a favorable oxidative environment, which is one of a principal determinant of normal endothelial function. The present study aimed to determine the effect of functional food consumption enriched in four nutrients (Nutri4) on microvascular endothelium-dependent and endothelium-independent vasodilation of skin microcirculation in competitive athletes. Design and method: Thirty-one competitive athletes were divided to Nutri4 group (N = 17) who ate three n-3 PUFAs, selenium, lutein, and vitamin E enriched hen eggs/daily for 3 weeks (mg per egg: n-3 PUFAs 342, selenium 0.0191, lutein 0.616, vitamin E 1.098), and Control group (N = 14) who ate three regular hens’ eggs/daily (mg per egg: n-3 PUFAs 146, selenium 0.0183, lutein 0.110, vitamin E 0.595). Blood pressure (BP), body mass index (BMI), body composition and serum lipid profile were measured before and after respective dietary protocol. Microvascular endothelium-dependent vasodilation in response to post-occlusive reactive hyperemia (PORH) and iontophoresis of acetylcholine (AChID), and endothelium-independent vasodilation in response to iontophoresis of sodium nitroprusside (SNP) was assessed by Laser Doppler flowmetry (LDF). Results: Mean arterial pressure (MAP) significantly decreased, and BMI, body composition and serum lipid profile remained unchanged following dietary protocol in Nutri4 group, while all variables remained unchanged in Control group. Microvascular PORH (R-O% before 162.6 ± 40.1 vs. after 185.5 ± 63.8, P = 0.050) and AChID (flow increase before 15.6 ± 4.7 vs. after 18.8 ± 5.0, P = 0.045) was significantly increased, while SNPID remained unchanged following dietary protocol in Nutri4 group (flow increase before 15.8 ± 4.9 vs. 14.0 ± 4.2, P = 0.209). In contrast, none was significantly changed in Control group. Conclusions: Consumption of n-3 PUFA, selenium, lutein, and vitamin E enriched functional foods improves peripheral endothelium-dependent microvascular reactivity in competitive athletes, independently of changes in BP and blood lipid concentrations. Importantly, consumption of large amounts of regular hen eggs (3/day for 3 weeks) did not have a detrimental effect on vascular function, BP and serum lipid profiles in athletes.

MATERNAL SALT INTAKE AND MICROVASCULAR ENDOTHELIAL FUNCTION DURING THE THIRD TRIMESTER OF HEALTHY PREGNANCY

Objective: Even in healthy individuals, high-salt (HS) loading leads to endothelial dysfunction, a hallmark of cardiometabolic diseases, independently of the changes in blood pressure (BP). Still, the effect of the amount of daily salt intake during healthy pregnancy on maternal endothelium-dependent vascular reactivity has not yet been investigated. Thus, this study aimed to assess the effect of the amount of daily salt intake during third trimester of pregnancy on maternal microvascular reactivity to stimuli in healthy pregnant women. Design and method: The present study was designed as a cross-sectional study in which all the data for each pregnant woman were obtained at one-time point between 37 and 40 weeks of gestation. Daily salt intake was estimated based on 24-h urinary sodium excretion using appropriate formula [1-g salt (NaCl) = 393.4 mg Na = 17.1 mmol Na]. Microvascular endothelium-dependent vasodilation in response to vascular occlusion (PORH), iontophoresis of acetylcholine (AChID) and local heating (HEAT), as well as endothelium-independent vasodilation in response to iontophoresis of sodium nitroprusside (SNP) was assessed by Laser Doppler flowmetry (LDF). Results: Preliminary results of the present study involve data obtained from 27 healthy pregnant women. According to the amount of daily salt intake, pregnant women were divided in low-salt (LS, &lt; 5 g of salt/day, N = 4), normal-to-high salt (NHS, 5.0–7.5 g of salt/day, N = 12) and high-salt (HS, &gt; 7.5 g of salt/day, N = 11) group. All pregnant women were normotensive, and BP values did not differ between groups. HEAT was significantly lower in HS compared to LS and NHS group, while PORH and AChID tended to be lower in HS compared to LS and NHS group, but without statistical significance. SNPID did not significantly differ between the groups. There was weak to moderate negative correlation between daily salt intake and functional markers of microvascular endothelium-dependent vasodilation (PORH, AChID and HEAT). Conclusions: The amount of daily salt intake significantly affects maternal endothelium-dependent microvascular reactivity during third trimester of healthy pregnancy, i.e. the increased salt intake significantly reduces the endothelium-dependent dilatation of the skin microcirculation, especially responses mediated by nitric-oxide (NO).

Nanomaterial Inhalation During Pregnancy Alters Systemic Vascular Function in a Cyclooxygenase-Dependent Manner.

Pregnancy requires rapid adaptations in the uterine microcirculation to support fetal development. Nanomaterial inhalation is associated with cardiovascular dysfunction, which may impair gestation. We have shown that maternal nano-titanium dioxide (nano-TiO2) inhalation impairs microvascular endothelial function in response to arachidonic acid and thromboxane (TXA2) mimetics. However, the mechanisms underpinning this process are unknown. Therefore, we hypothesize that maternal nano-TiO2 inhalation during gestation results in uterine microvascular prostacyclin (PGI2) and TXA2 dysfunction. Pregnant Sprague-Dawley rats were exposed from gestational day 10-19 to nano-TiO2 aerosols (12.17 ± 1.67 mg/m3) or filtered air (sham-control). Dams were euthanized on gestational day 20, and serum, uterine radial arterioles, implantation sites, and lungs were collected. Serum was assessed for PGI2 and TXA2 metabolites. TXB2, the stable TXA2 metabolite, was significantly decreased in nano-TiO2 exposed dams (597.3 ± 84.4 vs 667.6 ± 45.6 pg/ml), whereas no difference was observed for 6-keto-PGF1α, the stable PGI2 metabolite. Radial arteriole pressure myography revealed that nano-TiO2 exposure caused increased vasoconstriction to the TXA2 mimetic, U46619, compared with sham-controls (-41.3% ± 4.3% vs -16.8% ± 3.4%). Nano-TiO2 exposure diminished endothelium-dependent vasodilation to carbaprostacyclin, a PGI2 receptor agonist, compared with sham-controls (30.0% ± 9.0% vs 53.7% ± 6.0%). Maternal nano-TiO2 inhalation during gestation decreased nano-TiO2 female pup weight when compared with sham-control males (3.633 ± 0.064 vs 3.995 ± 0.124 g). Augmented TXA2 vasoconstriction and decreased PGI2 vasodilation may lead to decreased placental blood flow and compromise maternofetal exchange of waste and nutrients, which could ultimately impact fetal health outcomes.

New paeonol derivative C302 reduces hypertension in spontaneously hypertensive rats through endothelium-dependent and endothelium-independent vasodilation

Hypertension is a major risk factor for cardiovascular disease and Chinese herb monomers could provide new structural skeletons for anti-hypertension new drug development. Paeonol is a Chinese herbal monomer extracted from Cortex moutan, exhibited some anti-hypertensive activity. The study focused on the structural optimization of paeonol to provide promising lead compounds for anti-hypertension new drug development. Herein, twelve new paeonol derivatives (PD) were designed and synthesized and their vasodilation activity was evaluated by in vitro vasodilation drug screening platform based on Myograph. Its anti-hypertension activity, PD-C302 (2-hydroxy-4-methoxyvalerophenone) as a representative with the optimal vasodilation activity, was determined by its response to blood pressure in spontaneously hypertensive rats (SHR) in vivo. Moreover, its molecular mechanism was probed by the vasodilation activity of rat superior mesenteric artery rings with or without endothelium pre-contracted by potassium chloride (KCl) or phenylephrine hydrochloride (PE). It was indicated that PD-C302 significantly reduced the blood pressure in SHR, which would involve in PD-C302-induced vasodilation. Furthermore, endothelium-dependent pathways and endothelium-independent pathways both contributed importantly to PD-C302-induced vasodilation at low concentration of PD-C302. Endothelium-independent pathways (vascular smooth muscle cell-mediated vasodilation), were mainly responsible for the PD-C302-induced vasodilation at high concentration of PD-C302, which involved in opening multiple K+ channels to restrain Ca2+ channels, and then triggered vasodilation to reduce blood pressure. PD-C302 has a simple structure and favorable anti-hypertensive activity in vivo, which could be a promising lead compound for anti-hypertension new drug development.

Adenylate cyclase type 9 antagonizes cAMP accumulation and regulates endothelial signalling involved in atheroprotection.

The adenylate cyclase type 9 (ADCY9) gene appears to determine atherosclerotic outcomes in patients treated with dalcetrapib. In mice, we recently demonstrated that Adcy9 inactivation potentiates endothelial function and inhibits atherogenesis. The objective of this study was to characterize the contribution of ADCY9 to the regulation of endothelial signalling pathways involved in atherosclerosis. We show that ADCY9 is expressed in the endothelium of mouse aorta and femoral arteries. We demonstrate that ADCY9 inactivation in cultured endothelial cells paradoxically increases cAMP accumulation in response to the adenylate cyclase activators forskolin and vasoactive intestinal peptide (VIP). Reciprocally, ADCY9 overexpression decreases cAMP production. Using mouse femoral artery arteriography, we show that Adcy9 inactivation potentiates VIP-induced endothelial-dependent vasodilation. Moreover, Adcy9 inactivation reduces mouse atheroma endothelial permeability in different vascular beds. ADCY9 overexpression reduces forskolin-induced phosphorylation of Ser157-vasodilator-stimulated phosphoprotein (VASP) and worsens thrombin-induced fall of RAP1 activity, both leading to increased endothelial permeability. ADCY9 inactivation in thrombin-stimulated human coronary artery endothelial cells results in cAMP accumulation, increases p-Ser157-VASP, and inhibits endothelial permeability. MLC2 phosphorylation and actin stress fibre increases in response to thrombin were reduced by ADCY9 inactivation, suggesting actin cytoskeleton regulation. Finally, using the Miles assay, we demonstrate that Adcy9 regulates thrombin-induced endothelial permeability in vivo in normal and atherosclerotic animals. Adcy9 is expressed in endothelial cells and regulates local cAMP and endothelial functions including permeability relevant to atherogenesis.

Sex-related differences in endothelium-dependent vasodilation of human gingiva

BackgroundSex hormones influence circulation, periodontitis, and wound healing. The aim of the study was to compare the endothelium-dependent and independent vasodilation in human gingiva in men and women.MethodsGingival blood flow was evaluated in twelve male and twelve female subjects with healthy gingiva and no systemic conditions after acetylcholine or nitric oxide donor (NitroPOHL). Agonists were administered into the gingival sulcus at the right secondary incisor (test site). Regional gingival blood flow (GBF) was imaged by Laser Speckle Contrast Imager from the marginal gingiva to the mucogingival junction in four consecutive regions (coronal, midway1, midway2 and apical). Blood flow was expressed in Laser Speckle Perfusion Unit (LSPU). The absolute maximal blood flow change (Dmax), the area under the blood flow curve (AUC), and the time to peak (TTP) were calculated.ResultsMales had higher baseline GBF than females (257 ± 18.2 vs. 225 ± 18.8 LSPU, p < 0.001). Acetylcholine and NitroPOHL significantly increased the GBF in all test regions. The Dmax after the acetylcholine was reduced apically compared to the coronal (90 ± 13 LSPU vs. 117 ± 7 LSPU, p < 0.01), but it was similar after NitroPOHL (78 ± 9 LSPU vs. 86 ± 6 LSPU, p = 0.398) in both sexes. The Dmax and AUC were higher, and the TTP was smaller in men in most regions after acetylcholine but not after NitroPOHL.ConclusionIn the human gingiva, the endothelium-independent vasodilation propagates without attenuation in the line of the vascular supply in both sexes. At the same time, the endothelium-dependent ascending vasodilation attenuates similarly in men and women. However, men had more pronounced endothelium-dependent vasodilation than women. Therefore, it might contribute to the increased severity of periodontal disease in men.Trial registrationThe study was registered with ClinicalTrials.gov on 09.06.2021 (NCT04918563).

The Antifibrotic and the Anticarcinogenic Activity of Capsaicin in Hot Chili Pepper in Relation to Oral Submucous Fibrosis

A burning sensation on eating spicy foods purportedly supports the role of capsaicin, an active component of chili peppers, in the etiology of oral submucous fibrosis (OSF). Although the mast cell mediators and activated P2X receptors induce a constant burning sensation through an ATP-dependent mechanism, it is the activation of the transient receptor potential vanilloid 1 (TRPV-1) receptor by capsaicin that aggravates it. The molecular basis for the burning pain in OSF is thus attributable to the activation of TRPV1. There is overwhelming evidence that confirms capsaicin has more of a protective role in attenuating fibrosis and is potentially therapeutic in reversing conditions linked to collagen accumulation. The activation of TRPV-1 by capsaicin increases intracellular calcium ([Ca2+]i), upregulates AMP-activated protein kinase (AMPK) and Sirtuin-1 (SIRT-1), to enrich endothelium-dependent vasodilation via endothelial nitric oxide synthase (eNOS). The induction of vasodilation induces antifibrotic effects by alleviating hypoxia. The antifibrotic effects of capsaicin are mediated through the upregulation of antioxidant enzymes, downregulation of inflammatory genes and suppression of new collagen fibril formation. Capsaicin also demonstrates an anticarcinogenic effect by upregulating the cytotoxic T cells and downregulating regulatory T cells through the inhibition of angiogenesis and promotion of apoptosis. Judicious administration of capsaicin with an appropriate delivery mechanism may have therapeutic benefits in reducing pain sensation, rendering antifibrotic effects, and preventing the malignant transformation of OSF. This paper provides an overview of the molecular basis of capsaicin and its therapeutic application as an antifibrotic and anticarcinogenic agent for the treatment of OSF.

Microvascular Function in Skeletal Muscle of Adiponectin Knockout Mice

Adiponectin is known to be an important regulator of both metabolic and vascular function in skeletal muscle; however, a direct role for adiponectin in exercise training‐induced microvascular adaptation of skeletal muscle has not been documented. We assessed oxidative metabolism, capillarity, and endothelium‐dependent vasodilation in soleus and gastrocnemius muscles of sedentary and exercise trained, wild type (WT) and adiponectin knockout (AdipoKO) mice. WT and AdipoKO mice were obtained at 10‐12 wks of age and underwent treadmill exercise training (1 hr/day, 5 days/wk for 8 wks) or remained sedentary in cages. In sedentary mice, citrate synthase activity and capillarity were increased in soleus muscle of AdiopKO mice as compared to WT mice. In soleus muscle feed arteries from sedentary mice, endothelium‐dependent vasodilation to acetylcholine was reduced in AdipoKO mice as compared to WT mice. Exercise training increased capillarity and citrate synthase activity in soleus muscle of WT mice, but not AdipoKO mice. Exercise training did not alter endothelium‐dependent dilation in soleus feed arteries from either AdipoKO or WT mice. In 1A arterioles from the gastrocnemius muscle of sedentary mice, endothelium‐dependent vasodilation to acetylcholine was not altered in AdipoKO compared to WT mice; however, exercise training increased endothelium‐dependent vasodilation to acetylcholine in WT, but not AdipoKO mice. These data suggest that deletion of adiponectin and a reduction of endothelial vasodilatory function stimulates a compensatory increase in oxidative capacity and capillarity in soleus muscle; however, no further increase in these parameters occurs in soleus muscle of AdipoKO mice in response to exercise training. In contrast, in gastrocnemius muscle, endothelial vasodilatory function was not affected by deletion of adiponectin in sedentary mice, but endothelium‐dependent vasodilation of 1A arterioles increased in response to exercise training in WT, but not in AdipoKO mice. Taken together, these data suggest that the role of adiponectin in adaptation of metabolic and microvascular function in response to exercise training is muscle‐specific.

The Regulatory Role of miR‐21 in Coronary Microcirculation

IntroductionCoronary microvascular dysfunction is characterized by impaired endothelial‐dependent vasodilation. These impairments are seen in diabetic cardiomyopathy (DCM), coronary artery disease (CAD) and ischemia with non‐obstructive coronary artery (INOCA), Takotsubo cardiomyopathy, myocardial infarction with non‐obstructive coronary artery disease (MINOCA), and heart failure with preserved ejection fraction (HFpEF), but detailed mechanisms have yet to be elucidated.MethodsmicroRNA‐21 (miR‐21) global and conditional knockout mice were used to study how miR‐21 regulates coronary microcirculation in pathological conditions like DCM. Both genetic (db/db) and diet‐induced diabetic models were used. Coronary arteries were isolated, and endothelial‐dependent vasodilation was assessed using myography (DMT). In vivo myocardial blood flow (MBF) under stress was measured by contrast echocardiography or doppler after the treatment with different dosages of norepinephrine. Quantitative polymerase chain reaction (qPCR) was performed for gene expression analysis. Trichrome staining and histology were performed for structural changes of the hearts.ResultsOur preliminary data show that miR‐21 is upregulated in DCM and the deficiency of miR‐21 restores the endothelial‐dependent vasodilation in isolated diabetic coronary arterioles and coronary blood flow under stress in DCM through the mechanism that miR‐21 prevents the mediator of coronary vasodilation switching from NO to H2O2 in diabetes.ConclusionsmiR‐21 regulates microvascular dysfunction in DCM. Further genetic profiling will elucidate the pathways and mechanisms converging with miR‐21 to regulate microvascular function.

Low vs. High Wattage Vaping during Pregnancy Influences Vascular Function in Rat Offspring

Electronic cigarettes (e‐cigs) are being marketed as a healthier alternative to traditional cigarettes, yet the health consequences of e‐cig usage (also called vaping) are still being investigated. E‐cigs are easily customized for user preferences. For example, choice of flavors, nicotine concentration, and/or temperature (i.e. wattage) used to combust the e‐liquid can be selected in many devices. Emerging evidence suggest vaping during pregnancy impairs cerebral vascular function in rodent offspring. In this study, we sought to investigate the potential effects of changes in e‐cig device wattage (i.e. 5 watts vs 30 watts) with maternal vaping during pregnancy of vascular function in postnatal life of offspring. METHODS: Adult female Sprague Dawley rats were time‐mated to allow for maternal e‐cig exposure beginning on gestation day 2 until birth. Maternal vaping occurred for 1 h/day, 5 days/wk using a whole‐body chamber system. E‐cig aerosol was generation using D19 Joyetech atomizer with nicotine‐free (0 mg/mL) 50:50 VG:PG e‐liquid without flavoring. Puff topology was 83 ml with 5‐sec puff duration. Pregnant dams were randomly assigned to control (air‐exposed), 5 watt or 30‐watt exposure groups. Rat offspring (n=2/dam) were studied at 30‐, 90‐, and 180‐days after birth, where in vivo pulse wave velocity (an index of arterial stiffness) was assessed using VisualSonics Vevo 2100 ultrasound, thereafter animals were euthanized and thoracic aortas were excised, cleaned, and cut into 2mm rings for wire myography (DMT, AD instruments). Aortic rings were mounted and warmed in aerated Krebs‐Henseleit buffer solution. Vessel reactivity was measured using serial dilutions of methacholine [MCh 10‐9to 10‐5M] and sodium nitroprusside [SNP 10‐9 to 10‐5 M] to assess endothelial‐dependent vasodilation (EDD) and endothelium‐independent vasodilation (EID), respectively. RESULTS: At the 30‐days, max aortic EDD was not different between either 5W (79±17%, mean±SD) or 30W (86±4%) groups compared to controls (88±4%)(p&gt;0.36). At 90‐days, max aortic EDD was lower with 30W (58±18%, p&lt;0.001), but not 5W (78±4%, p=0.11) compared to controls (95±6%). Carotid PWV was elevated in 5W (3.49 m/s) and 30W (3.83 m/s) groups compared to controls (2.98 m/s, p&lt;0.05) suggesting 17‐29% increase in arterial stiffness. At 180 days, max aortic EDD was also lower with 30W (75±12%, p&lt;0.01), but not 5W (81±9x%, p=0.11) compared to controls (100±10%). Carotid PWV was elevated further in 5W (3.96 m/s) and 30W (4.29 m/s) groups compared to controls (3.13 m/s, p&lt;0.05) revealing 27‐37 % increase in arterial stiffness. Maximal aortic EID response (to SNP) was not different by wattage group or age. CONCLUSIONS: These findings show that e‐cig device power used during maternal vaping plays a role in increasing arterial stiffness and blunting EDD vascular function in the postnatal life of offspring with effects worsening with age. These data suggest vaping during pregnancy is not safe and has long‐lasting consequences to vascular health of progeny.

Activation of Endothelial Potassium Channels Lowers Pulmonary Arterial Pressure in Pulmonary Hypertension

Endothelium‐dependent vasodilation of small pulmonary arteries (PAs) lowers the resting pulmonary arterial pressure (PAP). Moreover, a loss of endothelium‐dependent vasodilation is a major contributor to elevated PAP in pulmonary hypertension (PH). Therefore, therapeutic strategies specifically targeting endothelial vasodilatory mechanisms may have beneficial effects on PAP in PH. In this regard, endothelial Ca2+ signaling mechanisms promote PA dilation and may present potential therapeutic targets for lowering PAP in PH. Under homeostatic conditions, Ca2+ signals activate endothelial nitric oxide synthase (eNOS) and Ca2+‐sensitive intermediate and small conductance potassium (IK and SK) channels to dilate PAs. eNOS activity and NO signaling are impaired in PH. However, the activity of IK/SK channels and its effect on PAP in PH have not been investigated. We hypothesized that IK/SK channels can be targeted for lowering PAP in PH. A mouse model of PH (chronic hypoxia + Sugen 5416, hereafter CH+Su, for 3 weeks) showed elevated right ventricular systolic pressure (RVSP, an indirect indicator of PAP) and development of pulmonary arterial lesions. We recently showed that adenosine triphosphate (ATP) dilates PAs through Ca2+‐dependent activation of eNOS in normal mice (Daneva et al., PNAS, 2021). PA pressure myography experiments demonstrated that ATP was unable to dilate PAs from CH+Su mice, confirming a loss of eNOS‐dependent vasodilation in these mice. However, PA dilation in response to IK/SK channel agonist NS309 (1 μM) was not different between PAs from control and CH+Su mice. Whole‐cell patch‐clamp studies in freshly isolated endothelial cells showed that IK/SK channel activity is not impaired in the endothelium from CH+Su mice. Finally, intraperitoneal administration of the IK/SK channel activator better suited for in vivo treatment, SKA‐31 (30 mg/kg), lowered the RVSP in CH+Su mice. Cardiac functional magnetic resonance imaging studies revealed that acute SKA‐31 administration does not alter the heart rate, stroke volume, ejection fraction, and cardiac output. Importantly, the RVSP‐lowering effect of SKA‐31 was not observed in normal mice. Collectively, our data reveal unaltered IK/SK channel activity in PH and provide proof of principle that IK/SK activation can be used as a strategy for lowering PAP in PH.

Hypoxic Preconditioning Attenuates Ischemia‐Reperfusion Injury in Older Adults

Sudden restoration of blood flow to an ischemic vessel paradoxically damages endothelial cells. In young healthy adults, ischemic preconditioning, caused by repeated periods of brief ischemia induced by local cuff inflation prior to reperfusion, attenuates endothelial dysfunction following an ischemia‐reperfusion injury. However, ischemic preconditioning does not consistently protect against ischemia‐reperfusion injury in older adults. Intermittent systemic hypoxemia, induced via brief bouts of breathing low levels of oxygen, attenuates endothelial dysfunction following an ischemia‐reperfusion injury in young healthy adults. Therefore, the aim of the present study was to determine whether intermittent hypoxia protects against ischemia‐reperfusion injury in older adults. Eleven older adults (4 women, age: 57±9 years, height: 173±8 cm, body weight: 76±13 kg) visited the laboratory on two separate occasions. Endothelium‐dependent vasodilation was assessed by brachial artery flow‐mediated dilation using a semiautomated diagnostic ultrasound system before and after 20 minutes of blood flow occlusion to induce an ischemia‐reperfusion injury. Blood flow occlusion was preceded by either intermittent hypoxia (IH), consisting of three 4‐min hypoxic cycles at a targeted arterial oxygen saturation of 80% interspersed with 4‐min room air cycles, or intermittent normoxia (IN), consisting of three 4‐min normoxic cycles separated by 4‐min room air cycles. Intermittent hypoxia resulted in an arterial oxygen saturation of 80±2%, which corresponded to oxygen levels of 11.6±1.0%. When preceded by intermittent normoxia, blood flow occlusion reduced flow‐mediated dilation by 4.0±2.6% (6.4±1.7 to 2.4±1.8%). In contrast, flow‐mediated dilation was reduced by 1.8±1.5% when blood flow occlusion was preceded by intermittent hypoxia (5.6±1.8 to 3.7±2.4%: p=0.05). Intermittent hypoxia increased cardiac output (5.2±1.5 to 5.7±1.8 L·min‐1, p=0.03) mainly due to an increase in heart rate (61±12 to 69±10 bpm, p&lt;0.01). In conclusion, hypoxic preconditioning attenuated the reduction in flow‐mediated dilation induced by blood flow occlusion in older adults. Thus, exposure to intermittent hypoxia represents a potential strategy to protect against ischemia‐reperfusion injury in populations at risk for ischemic events.

Stratification by Race Reveals Disparate Vascular Toxicity in Response to Anti‐Cancer Therapies

IntroductionCardiovascular toxicity is the primary reason for halting anti‐cancer therapy (CTx) or limiting the dose, and cardiovascular side effects of CTx represent a major clinical problem with implications for survival and quality of life. Ongoing work in our laboratory suggests that CTx induces microvascular endothelial dysfunction, which is a well‐established predictor of future CV events. CV disease in general and CTx‐induced adverse events are significantly more prevalent in Black patients (B) relative to non‐Hispanic White patients (NHW). Despite clinical evidence of these health disparities, little to no data exist to explain the underlying causes. Therefore, we tested the novel hypothesis that CTx‐induced microvascular dysfunction is augmented in B, which may explain the increase in cardiotoxic events in this population compared to NHW.MethodsFresh human tissues were obtained as de‐identified surgical discard specimens. Peripheral adipose arterioles (100–200 µm) from healthy B and NHW were incubated ex vivowith the CTx agents, doxorubicin (Dox), trastuzumab (TZM), or paclitaxel (PTX) for 16–20 h and used for isolated arteriole preparations. Endothelium‐dependent vasodilation in response to flow (Flow‐Mediated Dilation, FMD; 5–100 cmH2O pressure gradient) or acetylcholine (ACh; 10−9 to 10−5 M) and smooth muscle‐dependent dilation to papaverine (100 µM) were evaluated. Data are presented as % max. diameter ± SEM, N. Statistical significance was established with two‐way ANOVA RM.ResultsUnder control conditions, there was no difference in microvascular FMD in healthy B (ACh: 89.8±4.0%, n=5; 85.8±1.8%, n=6) vs. NHW (ACh: 86.2±3.2%, n=6; 78.7±5.9%, n=8). Ex vivo exposure to Dox impaired endothelial function in arterioles from both B and NHW (ACh: 45.0±10.5%, n=4 and 34.2±9.8%, n=7; FMD: Figure 1A). TZM impaired endothelial function to a greater extent in arterioles from B (ACh: 36.1±7.1%, n=3; FMD: Figure 1B) compared to NHW (ACh: 44.4±8.6%, n=8; FMD: Figure 1B). Interestingly, PTX did not affect endothelial function in NHW (ACh: 91.5±1.6%, n=4; FMD: Figure 1C), but impaired endothelial function in arterioles from B (ACh: 54.7±12.9%, n=3; FMD: Figure 1C). Max dilator capacity to the endothelium‐independent dilator papaverine was not changed in either group (not shown).ConclusionOur findings reveal disparate effects of CTx agents on microvascular endothelial function from B and NHW patients. This raises the possibility that microvascular dysfunction may contribute to the known disparities in adverse CV clinical outcomes of cancer patients and potentially other CV pathologies (e.g., disparities in adverse events associated with PTX‐eluting stents.) Future work should differentiate between biological/genetic vs. social/environmental contribution to observed microvascular responses to CTx.