Endothelin-1- and acetylcholine-mediated effects in human and rat vessels: impact of perivascular adipose tissue, diabetes, angiotensin II, and chemerin.

OBJECTIVE: To study the role of perivascular adipose tissue (PVAT) in the reactivity of rat and human vessels. METHODS: Iliac and mesenteric arteries were obtained from normotensive Sprague-Dawley rats, hypertensive transgenic (mRen2)27 rats overexpressing mouse renin, and (mRen2)27 rats made diabetic with streptozotocin. Human coronary arteries were obtained from donors. Concentration-response curves were constructed to endothelin-1 and acetylcholine with and without PVAT. The contribution of NO and endothelium-dependent hyperpolarization (EDH) were determined making use of the NO synthase inhibitor L-NAME and the EDH inhibitors apamin + TRAM-34. The endothelin type A and type B (ETA, ETB) receptor blockers BQ123 and BQ788, the chemerin inhibitors α-NETA and pravastatin, and the angiotensin receptor blocker losartan were also used. RESULTS: In rat iliac arteries, PVAT diminished endothelin-induced constriction, while the opposite was true in human coronaries. Coronary effects were unaltered by α-NETA, pravastatin, or losartan. ETB receptor-mediated relaxation in iliac arteries occurred only with PVAT, and BQ123 blocked endothelin-1-induced constriction. Diabetes upregulated the anticontractile effects of PVAT. In rat mesenteric arteries, acetylcholine-induced relaxation with PVAT relied on NO, and on NO + EDH without PVAT. Diabetes upregulated the EDH component exclusively with PVAT. CONCLUSION: PVAT modulates ET-1-induced constriction in a vessel type-dependent manner. Its enhancing effects in coronaries involved neither chemerin nor angiotensin II. Its anticontractile effects in rat iliac arteries involved ETB receptor-mediated relaxation. Diabetes upregulated PVAT's anticontractile effects. In mesenteric arteries, PVAT counterbalanced the EDH component of the relaxant effect of acetylcholine. Diabetes reversed this effect by upregulating the EDH component.

What is the context?The role of perivascular adipose tissue (PVAT) in vascular reactivity in pathological conditions is poorly understood.What is the study about?This study investigates the role of PVAT in vascular reactivity in animal and human vessels.What are the results?PVAT has vasoconstrictor and vasorelaxant effects depending on location and tissue. In human coronary arteries, PVAT-mediated vasoconstrictor effects do not involve chemerin or angiotensin II. PVAT's anticontractile effects in rat iliac arteries are mediated through a mechanism involving endothelin type B receptor-dependent relaxation. Moreover, diabetes but not hypertension dysregulates PVAT's anticontractile effects in rat mesenteric vessels.

BuyangHuanwu Decoction alleviates Endothelial Cell Apoptosis and Coronary Microvascular Dysfunction via Regulation of the MAPKK4/p38 Signaling Axis.

MAPKK4 has been implicated in the pathological mechanisms underlying myocardial and vascular injury, specifically influencing endothelial cell damage and programmed cell death via subcellular pathways. Nevertheless, the regulatory role of MAPKK4 in coronary microvascular injury following myocardial infarction remains unconfirmed, and the exploration of targeted mitochondrial protective therapeutic agents remains unaddressed. In light of this gap, we established a MAPKK4 gene-modified mouse model of ischemia-reperfusion injury and employed Buyang Huanwu decoction (BYHW), a traditional cardiovascular therapeutic formula, to assess its efficacy in treating coronary microvascular injury post-ischemia-reperfusion. The study aimed to elucidate the mechanism by which BYHW mitigates coronary microvascular injury induced by ischemia-reperfusion through the attenuation of endothelial cell apoptosis. Experimental outcomes revealed that high-dose BYHW significantly ameliorated coronary microvascular injury post-ischemia-reperfusion, restoring the structural integrity of the coronary microvasculature and reducing inflammation and oxidative stress. Contrarily, in transgenic mice overexpressing MAPKK4, BYHW intervention failed to attenuate microvascular inflammation and oxidative stress. To further investigate, we simulated hypoxia/reoxygenation injury in vascular endothelial cells using a MAPKK4-related cellular gene modification model. The results indicated that BYHW attenuates inflammatory damage and enhances the viability of vascular endothelial cells following hypoxic stress, inhibiting apoptosis via the mitochondrial pathway. However, overexpression of MAPKK4/p38 negated the therapeutic effects of BYHW, showing no impact on endothelial cell apoptosis and oxidative stress under hypoxic conditions. Molecular interaction studies confirmed that the active components of BYHW, Astragaloside IV and Ligustrazine, interact with the MAPKK4/P38 axis. In vitro experiments further suggested that the interaction between MAPKK4 and P38 play a crucial role in the ability of BYHW to inhibit apoptosis in coronary microvascular endothelial cells. Therapeutically, MAPKK4 may potentiate the apoptotic pathway in microvascular endothelial cells by modulating downstream P38 expression and phosphorylation, thereby exacerbating ischemia-reperfusion-induced coronary microvascular endothelial injury. From an in vivo perspective, the transgenic overexpression of MAPKK4 and P38 inhibited the microvascular protective effects of BYHW. These findings collectively underscore the significance of the MAPKK4-P38 axis in the protection of coronary microvascular endothelial cells.

Safety and Usefulness of Intracoronary Acetylcholine 200 µg Into the Left Coronary Artery as Vasoreactivity Testing: Comparisons With Intracoronary Acetylcholine Maximum 100 µg.

OBJECTIVES: We retrospectively analyzed the usefulness and safety of intracoronary acetylcholine (ACh) 200 µg into the left coronary artery (LCA) as vasoreactivity testing compared with intracoronary ACh 100 µg. METHODS: We recruited 1433 patients who had angina-like chest pain and intracoronary ACh testing in the LCA, including 1234 patients with a maximum ACh 100 µg and 199 patients with a maximum ACh 200 µg. ACh was injected in incremental doses of 20/50/100/200 µg into the LCA. Positive spasm was defined as ≥ 90% stenosis, usual chest pain, and ischemic electrocardiogram (ECG) changes. RESULTS: The incidence of coronary constriction ≥ 90%, usual chest pain, and ischemic ECG changes with a maximum ACh of 100 µg was markedly higher than that with a maximum ACh of 200 µg. The frequency of unusual chest pain in patients with a maximum ACh of 200 µg was higher than that in those with a maximum ACh of 100 µg (13% vs. 3%, p < 0.001). In patients with rest angina, positive spasm of maximum ACh 100 µg was significantly higher than that of maximum ACh 200 µg, whereas there was no difference regarding positive spasm in patients with atypical chest pain between the two ACh doses. Major complications (1.38% vs. 1.51%, p = 0.8565) and the occurrence of paroxysmal atrial fibrillation (1.81% vs. 2.63%, p = 0.6307) during ACh testing in the LCA were not different between the two maximum ACH doses. CONCLUSIONS: Intracoronary ACh 200 µg into the LCA is clinically useful and safe for vasoreactivity testing when intracoronary ACh 100 µg dose not provoke spasms.

Quercetin protects human coronary artery endothelial cells against hypoxia/reoxygenation-induced mitochondrial apoptosis via the Nrf2/HO-1 axis.

Our study explored the therapeutic effect and the mechanism of quercetin against hypoxia/reoxygenation (H/R)-induced injury in human coronary artery endothelial cells (CAECs). Quercetin was selected as a potential component for the BuShenKangShuaiPian formula (BSKSP) treatment via the Network pharmacology analysis. Cell viability and reactive oxygen species (ROS) production were measured by CCK8 assay and immunofluorescence, respectively. The expression of Bax, Bcl-2, Cle-caspase-3, cytochrome c (Cyt-C), NF-E2-related factor 2 (Nrf2), and heme oxygenase-1 (HO-1) protein was quantified by western blotting. The superoxide dismutase (SOD), catalase (CAT), malondialdehyde (MDA) activity, mtDNA copy number, and ATP production were measured via corresponding kits. Quercetin was selected from the BSKSP for its high degree value (Degree value: 22). Besides, quercetin protected CAECs against H/R-induced cytotoxicity and apoptosis. The H/R-induced increased ROS level, ATP production, Cyt-C release, and decreased mtDNA copy number were removed by the quercetin. Moreover, quercetin upregulated the Nrf2/ HO-1 axis, SOD, and CAT activity, and downregulated MDA levels in H/R treated CAECs, while knockdown Nrf2 reversed the protection of quercetin against H/R-induced oxidative stress, mitochondrial damage, and apoptosis. Quercetin protects CAECs against H/R-induced mitochondrial apoptosis via the Nrf2/HO-1 axis, which innovatively suggests the therapeutic potential of quercetin for coronary heart disease (CHD) treatment.

Differential expression of components of the CGRP-receptor family in human coronary and human middle meningeal arteries: functional implications.

BACKGROUND: Different responses in human coronary arteries (HCA) and human middle meningeal arteries (HMMA) were observed for some of the novel CGRP receptor antagonists, the gepants, for inhibiting CGRP-induced relaxation. These differences could be explained by the presence of different receptor populations in the two vascular beds. Here, we aim to elucidate which receptors are involved in the relaxation to calcitonin gene-related peptide (CGRP), adrenomedullin (AM) and adrenomedullin 2 (AM2) in HCA and HMMA. METHODS: RNA was isolated from homogenized human arteries (23 HCAs; 12 F, 11 M, age 50 ± 3 years and 26 HMMAs; 14 F, 12 M, age 51 ± 3 years) and qPCR was performed for different receptor subunits. Additionally, relaxation responses to CGRP, AM or AM2 of the human arteries were quantified using a Mulvany myograph system, in the presence or absence of the adrenomedullin 1 receptor antagonist AM22-52 and/or olcegepant. RESULTS: Calcitonin-like receptor (CLR) mRNA was expressed equally in both vascular beds, while calcitonin receptor (CTR) and receptor activity-modifying protein 3 (RAMP3) expression was low and could not be detected in all samples. RAMP1 expression was similar in HCA and HMMA, while RAMP2 expression was higher in HMMA. Moreover, receptor component protein (RCP) expression was higher in HMMA than in HCA. Functional experiments showed that olcegepant inhibits relaxation to all three agonists in both vascular beds. In HCA, antagonist AM22-52 did not inhibit relaxation to any of the agonists, while a trend for blocking relaxation to AM and AM2 could be observed in HMMA. CONCLUSION: Based on the combined results from receptor subunit mRNA expression and the functional responses in both vascular tissues, relaxation of HCA is mainly mediated via the canonical CGRP receptor (CLR-RAMP1), while relaxation of HMMA can be mediated via both the canonical CGRP receptor and the adrenomedullin 1 receptor (CLR-RAMP2). Future research should investigate whether RAMP2 predominance over RAMP1 in the meningeal vasculature results in altered migraine susceptibility or in a different response to anti-migraine medication in these patients. Moreover, the exact role of RCP in CGRP receptor signalling should be elucidated in future research.

Statin suppresses the development of excessive intimal proliferation in a Kawasaki disease mouse model.

Kawasaki disease (KD) causes vascular injury and lifelong remodeling. Excessive intimal proliferation has been observed, resulting in coronary artery lesions (CALs). However, the mechanisms underlying vascular remodeling in CAL and statin treatment have not been comprehensively elucidated. This study aimed to investigate the effects of statins on vascular remodeling using a KD mouse model. Candida albicans water-soluble substance (CAWS) was intraperitoneally injected in 5-week-old male apolipoprotein-E-deficient mice. They were categorized as follows (n = 4): control, CAWS, CAWS+statin, and late-statin groups. The mice were euthanized at 6 or 10 weeks after injection. Statins (atorvastatin) were initiated after CAWS injection, except for the late-statin group, for which statins were internally administered 6 weeks after injection. Elastica van Gieson staining and immunostaining were performed for evaluation. Statins substantially suppressed the marked neointimal hyperplasia induced by CAWS. Additionally, CAWS induced TGFß receptor II and MAC-2 expression around the coronary arteries, which was suppressed by the statins. KD-like vasculitis might promote the formation of aneurysm by destroying elastic laminae and inducing vascular stenosis by neointimal proliferation. The anti-inflammatory effects of statins might inhibit neointimal proliferation. Therefore, statin therapy might be effective in adult patients with KD with CAL by inhibiting vascular remodeling.

Chronic acetylcholinesterase inhibition reduces the effects of physical training on ventricular contractility and coronary bed reactivity in hypertensive rats.

Systemic arterial hypertension is accompanied by autonomic impairments that, if not contained, promotes cardiac functional and morphological damages. Pyridostigmine bromide (PYR) treatment results in positive effects on autonomic control and beneficial cardiac remodeling. These findings were also observed after aerobic physical training (APT). However, little is known about PYR effects on left ventricular contractility, mainly when it is combined with APT. We aimed to investigate the effects of chronic acetylcholinesterase inhibition on cardiac autonomic tone balance, coronary bed reactivity, and left ventricular contractility in spontaneously hypertensive rats (SHR) submitted to APT. Male SHR (18 weeks) were divided into two groups (N = 16): untrained and submitted to APT for 14 weeks (18th to 32nd week). Half of each group was treated with PYR (15 mg/kg/day) for two weeks (31st to 32nd week). The experimental protocol consisted of recording hemodynamic parameters, double autonomic blockade with atropine and propranolol, and assessment of coronary bed reactivity and ventricular contractility in isolated hearts using the Langendorff technique. PYR and APT reduced blood pressure, heart rate, and sympathetic influence on the heart. The Langendorff technique showed that APT increased coronary perfusion pressure and left ventricle contractility in response to coronary flow and ß-agonist administration. However, treatment with PYR annulled the effects of APT. In conclusion, although chronic treatment with PYR reduces cardiac sympathetic tonic influence, it does not favor coronary bed reactivity and cardiac contractility gains. PYR treatment in the trained SHR group nullified the coronary vascular reactivity and cardiac contractility gains.

Exogenous Growth Hormone Exacerbates Post-Irradiation Atherosclerosis in Susceptible Epicardial Coronary Arteries.

Cardiac exposure to ionizing radiation can damage both the microvasculature and coronary arteries, as well as increase the long-term risk of heart disease, myocardial fibrosis, and conduction abnormalities. Therapeutic agents capable of promoting recovery from radiation injury to the heart are limited. Growth hormone is linked to improved cardiac function following injury. Here, we leveraged a cynomolgus macaque model to determine the long-term outcomes of recombinant human growth hormone (rhGH) therapy on the heart following low-dose ionizing radiation. Macaques were exposed to 2 Gy radiation, treated with rhGH for one month, and assessed after 2 years. Overall, plasma lipid profile, cardiac function, and coronary artery disease were similar between rhGH and placebo treated animals. However, a subgroup of rhGH-treated animals exhibited more extensive atherosclerotic plaques in the coronary arteries. Together, these findings indicate that transient human growth hormone therapy subsequent to a single low dose of ionizing radiation involving the heart does not result in long-term changes to plasma cholesterol but may promote exacerbated coronary artery disease in a subset of individuals.

Basal release and relaxation responses to 6-nitrodopamine in swine carotid, coronary, femoral, and renal arteries.

Mammalian and reptilian vascular tissues present basal release of 6-nitrodopamine, which is reduced when the tissues are pre-incubated with the NO synthase inhibitor L-NG-Nitro arginine methyl ester (L-NAME), or when the endothelium is mechanically removed. 6-Nitrodopamine induces vasorelaxation in pre-contracted vascular rings by antagonizing the dopaminergic D2-like receptor. Here it was investigated whether male swine vessels (including carotid, left descendent coronary, renal, and femoral arteries) release 6-nitrodopamine, dopamine, noradrenaline, and adrenaline, as measured by liquid chromatography coupled to tandem mass spectrometry. The in vitro vasorelaxant action of 6-nitrodopamine was evaluated in carotid, coronary, renal, and femoral arteries precontracted by U-46619 (3 nM), and compared to that induced by the dopamine D2-receptor antagonist L-741,626. Expression of tyrosine hydroxylase and the neuromaker calretinin was investigated by immunohistochemistry. All vascular tissues presented basal release of endothelium-derived catecholamines. The relaxation induced by 6-nitrodopamine was not affected by preincubation of the tissues with either L-NAME (100 µM, 30-min preincubation) or the heme-site inhibitor of soluble guanylyl cyclase ODQ (100 µM, 30-min preincubation). Electrical field stimulation (EFS)-induced contractions were significantly potentiated by previous incubation with L-NAME, but unaffected by ODQ preincubation. The contractions induced by EFS were reduced by preincubation with either 6-nitrodopamine or L-741,626. Immunohistochemistry in all arteries revealed the presence of tyrosine hydroxylase in the endothelium, whereas immunoreactivity for calretinin was negative. Swine vessels present basal release of endothelium-derived catecholamines and expression of tyrosine hydroxylase in the endothelium. The vasodilation induced by 6-nitrodopamine is due to blockade of dopaminergic D2-like receptors.

3-methoxycatechol causes vasodilation likely via KV channels: ex vivo, in silico docking and in vivo study.

Substituted catechols include both natural and synthetic compounds found in the environment and foods. Some of them are flavonoid metabolites formed by the gut microbiota which are absorbed afterwards. Our previous findings showed that one of these metabolites, 4-methylcatechol, exerts potent vasorelaxant effects in rats. In the current study, we aimed at testing of its 22 structural congeners in order to find the most potent structure and to investigate the mechanism of action. 3-methoxycatechol (3-MOC), 4-ethylcatechol, 3,5-dichlorocatechol, 4-tert-butylcatechol, 4,5-dichlorocatechol, 3-fluorocatechol, 3-isopropylcatechol, 3-methylcatechol and the parent 4-methylcatechol exhibited high vasodilatory activities on isolated rat aortic rings with EC50s ranging from ∼10 to 24 µM. Some significant sex-differences were found. The most potent compound, 3-MOC, relaxed also resistant mesenteric artery but not porcine coronary artery, and decreased arterial blood pressure in both male and female spontaneously hypertensive rats in vivo without affecting heart rate. It potentiated the vasodilation mediated by cAMP and cGMP, but did not impact L-type Ca2+-channels. By using two inhibitors, activation of voltage-gated potassium channels (KV) was found to be involved in the mechanism of action. This was corroborated by docking analysis of 3-MOC with the KV7.4 channel. None of the most active catechols decreased the viability of the A-10 rat embryonic thoracic aorta smooth muscle cell line. Our findings showed that various catechols can relax vascular smooth muscles and hence could provide templates for developing new antihypertensive vasodilator agents without affecting coronary circulation.

Relationship between peripheral and intracoronary blood flow in patients with angina and nonobstructive coronary arteries.

Coronary vasomotor dysfunction, an important underlying cause of angina and nonobstructive coronary arteries (ANOCA), encompassing coronary vasospasm, coronary endothelial dysfunction, and/or coronary microvascular dysfunction, is clinically assessed by invasive coronary function testing (ICFT). As ICFT imposes a high burden on patients and carries risks, developing noninvasive alternatives is important. We evaluated whether coronary vasomotor dysfunction is a component of systemic microvascular endothelial and smooth muscle dysfunction and can be detected using laser speckle contrast analysis (LASCA). Forty-three consecutive patients with ANOCA underwent ICFT, with intracoronary acetylcholine, adenosine, and flow measurements, to assess coronary vasomotor dysfunction. Cutaneous microvascular function was assessed using LASCA in the forearm, combined with vasodilators acetylcholine, sodium nitroprusside, and insulin and using EndoPAT, by measuring the reactive hyperemia index (RHI). Of the 43 included patients with ANOCA (79% women, 59 ± 9 yr old), 38 patients had coronary vasomotor dysfunction, including 28 with coronary vasospasm, 26 with coronary endothelial dysfunction, and 18 with coronary microvascular dysfunction, with overlapping endotypes. Patients with and without coronary vasomotor dysfunction had similar peripheral flow responses to acetylcholine, insulin, and RHI. In contrast, coronary vasomotor dysfunction was associated with lower peripheral flow responses to sodium nitroprusside (P < 0.001). An absolute flow response to sodium nitroprusside of 83.95 APU resulted in 86.1% sensitivity and 80.0% specificity for coronary vasomotor dysfunction (area under the ROC curve, 0.883; P = 0.006). In conclusion, this study provides evidence of systemic vascular smooth muscle dysfunction in patients with ANOCA with coronary vasomotor dysfunction and the diagnostic value of peripheral microvascular function testing as a noninvasive tool for detecting coronary vasomotor dysfunction.NEW & NOTEWORTHY This study provides proof of concept that assessment of the peripheral vasculature, particularly vascular smooth muscle cells measured using the LASCA technology holds potential as a noninvasive tool for detecting coronary vasomotor dysfunction. This finding highlights the potential of the LASCA technology in, for example, medication studies for coronary vasomotor dysfunction, especially when investigating whether medication improves vascular function, as repeated peripheral measurements are less invasive than invasive coronary function testing, the current gold standard.

Effect of acute intravenous beta-blocker administration on myocardial blood flow during same-day hybrid CCTA/PET imaging.

This study aimed to evaluate the impact of acute intravenous beta-blocker administration on myocardial blood flow (MBF) during same-day hybrid coronary computed tomography angiography (CCTA) and 13N-ammonia positron emission tomography (PET) myocardial perfusion imaging (MPI). Previous research on the discontinuation of oral beta-blockers before MPI has shown mixed results, with no studies yet exploring the acute intravenous administration in the context of same-day hybrid imaging. This retrospective study included patients with suspected chronic coronary syndromes undergoing same-day hybrid CCTA/13N-ammonia PET MPI. Exclusion criteria comprised coronary artery stenosis ≥ 50% or regional perfusion abnormalities on PET, and baseline oral beta-blocker medication. Intravenous metoprolol (up to 30 mg) was administered as needed for heart rate control before CCTA. MBF measurements were obtained at rest (rMBF) and during stress (sMBF), and myocardial flow reserve (MFR) was calculated. After excluding 281 patients, 154 were eligible for propensity-score matching, resulting in 108 patients divided into two equal groups based on beta-blocker administration. The groups showed no significant differences in baseline characteristics. Among those who received beta-blockers, there was a significant decrease in sMBF (2.21 [IQR 1.72-2.78] versus 2.46 [2.08-2.99] ml∙min-1∙g-1, p = 0.027) and MFR (3.46 [2.70-4.05] versus 3.79 [3.22-4.46], p = 0.030), respectively, compared to those who did not receive beta-blockers. In contrast, rMBF remained unaffected (0.65 [0.54-0.78] versus 0.64 [0.55-0.76] ml∙min-1∙g-1, p = 0.931). Acute intravenous beta-blocker administration significantly impacts MBF, leading to a slight reduction in sMBF and MFR. In contrast, rMBF appears unaffected, suggesting that beta-blockers primarily affect the coronary capacity to respond to vasodilators.

Anti-Inflammatory Effect of Atorvastatin on Primary Human Endothelial Cells Incubated under Genotoxic Load.

The level of cytokine expression was measured in human coronary artery (HCAEC) and internal thoracic artery (HITAEC) endothelial cells exposed to 500 ng/ml alkylating mutagen mitomycin C (MMC) and 5 µM atorvastatin. It was found that treatment of MMC-exposed HCAEC with atorvastatin decreased secretion of macrophage migration inhibitory factor (MIF), IL-8, and IL8 gene expression, but increased the expression of SERPINE1 gene encoding the PAI-1 protein. In atorvastatin-treated HITAEC, the concentration of MIF protein and the expression of the IL8 and SERPINE1 genes were reduced. We can conclude that atorvastatin prevents proinflammatory activation of endothelial cells cultured under conditions of genotoxic load. However, the molecular mechanisms of this effect require further research.

Lack of Class I Vasoreactivity Testing for Diagnosing Patients With Coronary Artery Spasm.

BACKGROUND: Vasoreactivity testing, such as intracoronary acetylcholine (ACh) or ergometrine (EM), is defined as Class I for the diagnosis of patients with vasospastic angina (VSA) according to recommendations from the Coronary Vasomotion Disorders International Study (COVADIS) group and guidelines from the Japanese Circulation Society (JCS). HYPOTHESIS: Although vasoreactivity testing is a clinically useful tool, it carries some risks and limitations in diagnosing coronary artery spasm. METHODS: Previous reports on vasoreactivity testing for diagnosing the presence of coronary spasm are summarized from the perspective of Class I. RESULTS: There are several problems such as reproducibility, underestimation, overestimation, and inconclusive/nonspecific results associated with daily spasm. Because provoked spasm caused by intracoronary ACh is not always similar to that caused by intracoronary EM, possibly due to different mediators, supplementary use of these vasoreactivity tests is necessary for cardiologists to diagnose VSA when a provoked spasm is not revealed by each vasoactive agent. CONCLUSIONS: Cardiologists should understand the imperfection of these vasoreactivity tests when diagnosing patients with VSA.

Exploring developmental MeHg impact on extraembryonic and cardiac vessels and its effect on cardiomyocyte contractility.

The toxicity of methylmercury (MeHg) during embryonic development is a relevant issue that remains unclear and deserves investigation. In this sense, there is evidence that links the intake of contaminated food with cardiovascular pathologies in human adults and children. Thus, this study aimed to verify the impact of MeHg on the structure and integrity of extraembryonic and cardiac blood vessels and the contractile function of cardiomyocytes, also evaluating embryonic weight and the cardiosomatic index (CSI). Thus, chicken embryos, used as an experimental model, were exposed to a single dose of 0.1 µg MeHg/50 µl saline at E1.5 and analyzed at E10. After exposure, an increase in the number of extraembryonic blood vessels and the veins of the cardiac tissue was observed. These increases were accompanied by a reduction in the content of VEGF and VCAM proteins related to vessel growth and adhesiveness. Together, these results were related to reduced nitrite (NOx) levels. Furthermore, MeHg reduces the number of sarcomeres and increases the content of cardiac troponin I (cTnI), a protein that regulates contraction. In general, exposure to MeHg affected the integrity of extraembryonic and cardiac vessels and the contractile function of cardiomyocytes, which had a systemic impact evidenced by the reduction in embryonic weight gain and CSI.

IL-1ß Induces LDL Transcytosis by a Novel Pathway Involving LDLR and Rab27a.

BACKGROUND: In early atherosclerosis, circulating LDLs (low-density lipoproteins) traverse individual endothelial cells by an active process termed transcytosis. The CANTOS trial (Canakinumab Antiinflammatory Thrombosis Outcome Study) treated advanced atherosclerosis using a blocking antibody for IL-1ß (interleukin-1ß); this significantly reduced cardiovascular events. However, whether IL-1ß regulates early disease, particularly LDL transcytosis, remains unknown. METHODS: We used total internal reflection fluorescence microscopy to quantify transcytosis by human coronary artery endothelial cells exposed to IL-1ß. To investigate transcytosis in vivo, we injected wild-type and knockout mice with IL-1ß and LDL to visualize acute LDL deposition in the aortic arch. RESULTS: Exposure to picomolar concentrations of IL-1ß induced transcytosis of LDL but not of albumin by human coronary artery endothelial cells. Surprisingly, expression of the 2 known receptors for LDL transcytosis, ALK-1 (activin receptor-like kinase-1) and SR-BI (scavenger receptor BI), was unchanged or decreased. Instead, IL-1ß increased the expression of the LDLR (LDL receptor); this was unexpected because LDLR is not required for LDL transcytosis. Overexpression of LDLR had no effect on basal LDL transcytosis. However, knockdown of LDLR abrogated the effect of IL-1ß on transcytosis rates while the depletion of Cav-1 (caveolin-1) did not. Since LDLR was necessary but overexpression had no effect, we reasoned that another player must be involved. Using public RNA sequencing data to curate a list of Rab (Ras-associated binding) GTPases affected by IL-1ß, we identified Rab27a. Overexpression of Rab27a alone had no effect on basal transcytosis, but its knockdown prevented induction by IL-1ß. This was phenocopied by depletion of the Rab27a effector JFC1 (synaptotagmin-like protein 1). In vivo, IL-1ß increased LDL transcytosis in the aortic arch of wild-type but not Ldlr-/- or Rab27a-deficient mice. The JFC1 inhibitor nexinhib20 also blocked IL-1ß-induced LDL accumulation in the aorta. CONCLUSIONS: IL-1ß induces LDL transcytosis by a distinct pathway requiring LDLR and Rab27a; this route differs from basal transcytosis. We speculate that induction of transcytosis by IL-1ß may contribute to the acceleration of early disease.

Sex differences in CGRP-induced vasodilation of human middle meningeal arteries but not human coronary arteries: implications for migraine.

BACKGROUND: Migraine prevalence and levels of calcitonin gene-related peptide (CGRP), a peptide involved in migraine pathophysiology, differ between men and women, and appear to be affected by changes in sex hormones. The present study investigated the sex-specific responses to CGRP in human isolated arteries. METHODS: CGRP-induced relaxation of 62 (28 men and 34 women) human isolated middle meningeal arteries (HMMA) and 139 (69 men and 70 women) human isolated coronary arteries (HCA) was compared between men and women in groups <50 years and ≥50 years of age as a proxy for pre- and postmenopausal status in women, as well as matched-age groups for men. RESULTS: In HCA, no differences were observed between male and female tissue, or between the different age groups. However, in HMMA, the maximum response was significantly smaller and CGRP was less potent in females <50 compared with males <50 years of age. No differences were observed between the older age groups. CONCLUSIONS: Sex differences were observed for CGRP-induced relaxation of HMMA, but not HCA. These differences could arise from differential receptor expression in the vascular beds combined with the effect of sex hormones on CGRP and subsequent receptor desensitization.

Longitudinal assessment of coronary plaque regression related to sodium-glucose cotransporter-2 inhibitor using coronary computed tomography angiography.

BACKGROUND: Sodium-Glucose Cotransporter-2 Inhibitor (SGLT2i) is a novel oral drug for treating type 2 diabetes mellitus (T2DM) with demonstrated cardiovascular benefits. Previous studies in apolipoprotein E knockout mice have shown that SGLT2i is associated with attenuated progression of atherosclerosis. However, whether this effect extends to T2DM patients with coronary atherosclerosis in real-world settings remains unknown. METHODS: In this longitudinal cohort study using coronary computed tomography angiography (CCTA), T2DM patients who underwent ≥ 2 CCTA examinations at our center between 2019 and 2022 were screened. Eligible patients had multiple study plaques, defined as non-obstructive stenosis at baseline and not intervened during serial CCTAs. Exclusion criteria included a CCTA time interval < 12 months, prior SGLT2i treatment, or initiation/discontinuation of SGLT2i during serial CCTAs. Plaque volume (PV) and percent atheroma volume (PAV) were measured for each study plaque using CCTA plaque analysis software. Patients and plaques were categorized based on SGLT2i therapy and compared using a 1:1 propensity score matching (PSM) analysis. RESULTS: The study included 236 patients (mean age 60.5 ± 9.5 years; 69.1% male) with 435 study plaques (diameter stenosis ≥ 50%, 31.7%). Following SGLT2i treatment for a median duration of 14.6 (interquartile range: 13.0, 20.0) months, overall, non-calcified, and low-attenuation PV and PAV were significantly decreased, while calcified PV and PAV were increased (all p < 0.001). Meanwhile, reductions in overall PV, non-calcified PV, overall PAV, and non-calcified PAV were significantly greater in SGLT2i-treated compared to non-SGLT2i-treated plaques (all p < 0.001). PSM analysis showed that SGLT2i treatment was associated with higher reductions in overall PV (- 11.77 mm3 vs. 4.33 mm3, p = 0.005), non-calcified PV (- 16.96 mm3 vs. - 1.81 mm3, p = 0.017), overall PAV (- 2.83% vs. 3.36%, p < 0.001), and non-calcified PAV (- 4.60% vs. 0.70%, p = 0.003). These findings remained consistent when assessing annual changes in overall and compositional PV and PAV. Multivariate regression models demonstrated that SGLT2i therapy was associated with attenuated progression of overall or non-calcified PV or PAV, even after adjusting for cardiovascular risk factors, medications, and baseline overall or non-calcified PV or PAV, respectively (all p < 0.05). The effect of SGLT2i on attenuating non-calcified plaque progression was consistent across subgroups (all p for interaction > 0.05). CONCLUSIONS: In this longitudinal CCTA cohort of T2DM patients, SGLT2i therapy markedly regressed coronary overall PV and PAV, mainly result from a significant reduction in non-calcified plaque.