579 research outputs found

    Pollutant Particles Produce Vasoconstriction and Enhance MAPK Signaling via Angiotensin Type I Receptor

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    Exposure to particulate matter (PM) is associated with acute cardiovascular mortality and morbidity, but the mechanisms are not entirely clear. In this study, we hypothesized that PM may activate the angiotensin type 1 receptor (AT1R), a G protein-coupled receptor that regulates inflammation and vascular function. We investigated the acute effects of St. Louis, Missouri, urban particles (UPs; Standard Reference Material 1648) on the constriction of isolated rat pulmonary artery rings and the activation of extracellular signal-regulated kinases 1 and 2 (ERK1/2) and p38 mitogen-activated protein kinases (MAPKs) in human pulmonary artery endothelial cells with or without losartan, an antagonist of AT1R. UPs at 1–100 μg/mL induced acute vaso-constriction in pulmonary artery. UPs also produced a time- and dose-dependent increase in phosphorylation of ERK1/2 and p38 MAPK. Losartan pretreatment inhibited both the vasoconstriction and the activation of ERK1/2 and p38. The water-soluble fraction of UPs was sufficient for inducing ERK1/2 and p38 phosphorylation, which was also losartan inhibitable. Copper and vanadium, two soluble transition metals contained in UPs, induced pulmonary vasoconstriction and phosphorylation of ERK1/2 and p38, but only the phosphorylation of p38 was inhibited by losartan. The UP-induced activation of ERK1/2 and p38 was attenuated by captopril, an angiotensin-converting enzyme inhibitor. These results indicate that activation of the local renin–angiotensin system may play an important role in cardiovascular effects induced by PM

    Telomere shortening occurs in Asian Indian Type 2 diabetic patients

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    Aim: Telomere shortening has been reported in several diseases including atherosclerosis and Type 1 diabetes. Asian Indians have an increased predilection for Type 2 diabetes and premature coronary artery disease. The aim of this study was to determine whether telomeric shortening occurs in Asian Indian Type 2 diabetic patients. Methods: Using Southern‐blot analysis we determined mean terminal restriction fragment (TRF) length, a measure of average telomere size, in leucocyte DNA. Type 2 diabetic patients without any diabetes‐related complications (n = 40) and age‐ and sex‐matched control non‐diabetic subjects (n = 40) were selected from the Chennai Urban Rural Epidemiology Study (CURES). Plasma level of malondialdehyde (MDA), a marker of lipid peroxidation, was measured by TBARS (thiobarbituric acid reactive substances) using a fluorescence method. Results: Mean (± SE) TRF lengths of the Type 2 diabetic patients (6.01 ± 0.2 kb) were significantly shorter than those of the control subjects (9.11 ± 0.6 kb) (P = 0.0001). Among the biochemical parameters, only levels of TBARS showed a negative correlation with shortened telomeres in the diabetic subjects (r = −0.36; P = 0.02). However, telomere lengths were negatively correlated with insulin resistance (HOMA‐IR) (r = −0.4; P = 0.01) and age (r = −0.3; P = 0.058) and positively correlated with HDL levels (r = 0.4; P = 0.01) in the control subjects. Multiple linear regression (MLR) analysis revealed diabetes to be significantly (P < 0.0001) associated with shortening of TRF lengths. Conclusions: Telomere shortening occurs in Asian Indian Type 2 diabetic patients

    Influence of acute pancreatitis on the in vitro responsiveness of rat mesenteric and pulmonary arteries

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    <p>Abstract</p> <p>Background</p> <p>Acute pancreatitis is an inflammatory disease characterized by local tissue injury and systemic inflammatory response leading to massive nitric oxide (NO) production and haemodynamic disturbances. Therefore, the aim of this work was to evaluate the vascular reactivity of pulmonary and mesenteric artery rings from rats submitted to experimental pancreatitis.</p> <p>Male Wistar rats were divided into three groups: saline (SAL); tauracholate (TAU) and phospholipase A<sub>2 </sub>(PLA<sub>2</sub>). Pancreatitis was induced by administration of TAU or PLA<sub>2 </sub>from <it>Naja mocambique mocambique </it>into the common bile duct of rats, and after 4 h of duct injection the animals were sacrificed. Concentration-response curves to acetylcholine (ACh), sodium nitroprusside (SNP) and phenylephrine (PHE) in isolated mesenteric and pulmonary arteries were obtained. Potency (pEC<sub>50</sub>) and maximal responses (E<sub>MAX</sub>) were determined. Blood samples were collected for biochemical analysis.</p> <p>Results</p> <p>In mesenteric rings, the potency for ACh was significantly decreased from animals treated with TAU (about 4.2-fold) or PLA<sub>2 </sub>(about 6.9-fold) compared to saline group without changes in the maximal responses. Neither pEC<sub>50 </sub>nor E<sub>MAX </sub>values for Ach were altered in pulmonary rings in any group. Similarly, the pEC<sub>50 </sub>and the E<sub>MAX </sub>values for SNP were not changed in both preparations in any group. The potency for PHE was significantly decreased in rat mesenteric and pulmonary rings from TAU group compared to SAL group (about 2.2- and 2.69-fold, for mesenteric and pulmonary rings, respectively). No changes were seen in the E<sub>MAX </sub>for PHE. The nitrite/nitrate (NO<sub>x</sub><sup>-</sup>) levels were markedly increased in animals submitted to acute pancreatitis as compared to SAL group, approximately 76 and 68% in TAU and PLA<sub>2 </sub>protocol, respectively.</p> <p>Conclusion</p> <p>Acute pancreatitis provoked deleterious effects in endothelium-dependent relaxing response for ACh in mesenteric rings that were strongly associated with high plasma NO<sub>x</sub><sup>- </sup>levels as consequence of intense inflammatory responses. Furthermore, the subsensitivity of contractile response to PHE in both mesenteric and pulmonary rings might be due to the complications of this pathological condition in the early stage of pancreatitis.</p

    Resistant Hypertension Trials and Tribulations

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    Introduction Our case concerns a 62-year-old white woman who was referred by her general practitioner in 2012 with a long-standing history of difficult to control blood pressure (BP). She had significant past medical history including an excised meningioma and an implantable cardiac defibrillator for a single episode of polymorphic ventricular tachycardia during general anesthesia. She also had a possible diagnosis of epilepsy and tablet-controlled type-2 diabetes mellitus. On referral to our clinic she was on 5 antihypertensive medications including enalapril 40 mg daily, bisoprolol 10 mg daily, lercanidipine 10 mg daily, losartan 50 mg daily, and indapamide 2.5 mg once daily. She was also on metformin and sodium valproate. In clinic, she appeared well. She complained of occasional headaches but had no other symptom of note. She had no significant family history of high BP. On examination, she had a body mass index in the normal range and after repeated measures, her clinic BP was found to be 195/110 mm Hg. There was very little else to find on examination, including no murmurs or renal bruits. On fundoscopy, she had grade 2 hypertensive retinopathy. Baseline investigations did not reveal anything untoward. She had a normal blood count, renal function, and electrolytes. On urinalysis, she had mild proteinuria, with a urine protein-creatinine ratio of 17 (laboratory reference value 0–13 mg/mmol). Her ECG showed sinus rhythm with a normal rate, axis, and voltage. Her echocardiogram did not show any evidence of left ventricular hypertrophy, left ventricular ejection fraction was 58%, and she had evidence of mild diastolic dysfunction. Ambulatory BP monitoring (ABPM) was performed and her mean 24-hour BP was 190/105 mm Hg. The range was 118/67 to 227/127 mm Hg, with >90% of readings >140/90 mm Hg. So, here, we have a patient with a diagnosis of resistant hypertension according to the definition in the European guidelines

    Cardiovascular care of patients with stroke and high risk of stroke: The need for interdisciplinary action: A consensus report from the European Society of Cardiology Cardiovascular Round Table.

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    Comprehensive stroke care is an interdisciplinary challenge. Close collaboration of cardiologists and stroke physicians is critical to ensure optimum utilisation of short- and long-term care and preventive measures in patients with stroke. Risk factor management is an important strategy that requires cardiologic involvement for primary and secondary stroke prevention. Treatment of stroke generally is led by stroke physicians, yet cardiologists need to be integrated care providers in stroke units to address all cardiovascular aspects of acute stroke care, including arrhythmia management, blood pressure control, elevated levels of cardiac troponins, valvular disease/endocarditis, and the general management of cardiovascular comorbidities. Despite substantial progress in stroke research and clinical care has been achieved, relevant gaps in clinical evidence remain and cause uncertainties in best practice for treatment and prevention of stroke. The Cardiovascular Round Table of the European Society of Cardiology together with the European Society of Cardiology Council on Stroke in cooperation with the European Stroke Organisation and partners from related scientific societies, regulatory authorities and industry conveyed a two-day workshop to discuss current and emerging concepts and apparent gaps in stroke care, including risk factor management, acute diagnostics, treatments and complications, and operational/logistic issues for health care systems and integrated networks. Joint initiatives of cardiologists and stroke physicians are needed in research and clinical care to target unresolved interdisciplinary problems and to promote the best possible outcomes for patients with stroke

    Signaling of angiotensin II-induced vascular protein synthesis in conduit and resistance arteries in vivo

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    BACKGROUND: From in vitro studies, it has become clear that several signaling cascades are involved in angiotensin II-induced cellular hypertrophy. The aim of the present study was to determine some of the signaling pathways mediating angiotensin II (Ang II)-induced protein synthesis in vivo in large and small arteries. METHODS: Newly synthesized proteins were labeled during 4 hours with tritiated leucine in conscious control animals, or animals infused for 24 hours with angiotensin II (400 ng/kg/min). Hemodynamic parameters were measure simultaneously. Pharmacological agents affecting signaling cascades were injected 5 hours before the end of Ang II infusion. RESULTS: Angiotensin II nearly doubled the protein synthesis rate in the aorta and small mesenteric arteries, without affecting arterial pressure. The AT(1 )receptor antagonist Irbesartan antagonized the actions of Ang II. The Ang II-induced protein synthesis was associated with increased extracellular signal-regulated kinases (ERK)1/2 phosphorylation in aortic, but not in mesenteric vessels. Systemic administration of PD98059, an inhibitor of the ERK-1/2 pathway, produced a significant reduction of protein synthesis rate in the aorta, and only a modest decrease in mesenteric arteries. Rapamycin, which influences protein synthesis by alternative signaling, had a significant effect in both vessel types. Rapamycin and PD98059 did not alter basal protein synthesis and had minimal effects on arterial pressure. CONCLUSION: ERK1/2 and rapamycin-sensitive pathways are involved in pressure-independent angiotensin II-induced vascular protein synthesis in vivo. However, their relative contribution may vary depending on the nature of the artery under investigation
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