RESUMO
BACKGROUND: Anterior mitral leaflet prolapse repair is a highly effective procedure, but despite excellent operative results still has an inferior long-term durability when compared to posterior leaflet repair. METHODS: We analysed mitral repair durability in 74 consecutive patients operated for anterior leaflet prolapse between 2010 and 2021. Their pre- and postoperative clinical, echocardiographic data and repair durability as well, were compared with 74 randomly assigned posterior leaflet prolapse patients who underwent valve repair during the same period. RESULTS: While groups were of similar age, patients with anterior leaflet prolapse had an inferior preoperative status in terms of functional reserve, atrial fibrillation, operative risk, ejection fraction and had more dilated left heart chambers as well. 1, 5, and 10-year freedom from repair failure was 87.1 ± 4.6%, 79.8 ± 6.5% and 50.7 ± 12.5% in the anterior, and 98.5 ± 1.5% respectively in the posterior leaflet group. Atrial fibrilation (hazard ratio [HR] 5.365; 95%; confidence interval [CI] 1.093-26.324 p = .038) and left ventricle end-systolic diameter (HR 1.160 95%; CI 1.037-1.299 p = .010) independently predicted anterior leaflet repair failure. Receiver Operating Curve analysis established left ventricle end-systolic diameter ≤42 mm as a cut-off value associated with improved anterior leaflet repair durability. Accordingly, 10-year repair durability in a subset of patients, with preserved left ventricle end-systolic diameter (≤42 mm) was 86.4 ± 7.8%. CONCLUSION: Better long-term repair durability in patients with anterior mitral leaflet prolapse and preserved sinus rhytm and left-ventricle diameters justifies early reconstructive approach.
Assuntos
Insuficiência da Valva Mitral , Prolapso da Valva Mitral , Ecocardiografia , Humanos , Valva Mitral/diagnóstico por imagem , Valva Mitral/cirurgia , Insuficiência da Valva Mitral/diagnóstico por imagem , Insuficiência da Valva Mitral/cirurgia , Prolapso da Valva Mitral/diagnóstico por imagem , Prolapso da Valva Mitral/cirurgia , Prolapso , Resultado do TratamentoRESUMO
This paper presents the physicochemical characteristics and antioxidative, antibacterial and antiproliferative effects of nineteen samples of different honey types (acacia, linden, heather, sunflower, phacelia, basil, anise, sage, chestnut, hawthorn, lavender and meadow) collected from different locations in the Western Balkans (Republic of Serbia, Kosovo, Bosnia and Herzegovina, and Northern Macedonia). Physicochemical parameters (moisture, pH, electrical conductivity, free acidity, and hydroxymethylfurfural [HMF]) were analysed. Based on the obtained results, all tested honey samples were in agreement with EU regulation. The antioxidant potential of honey samples was assessed by determination of total phenolic content (TPC) and evaluation of scavenging activity towards diphenilpicrylhydrazyl radicals (DPPH·). The highest phenolic content was found in basil honey (101 ± 2.72 mg GAE/100 g), while the lowest was registered in rapeseed honey (11.5 ± 0.70 mg GAE/100 g). Heather, anise, phacelia, sage, chestnut and lavender honey samples were also rich in TP, containing 80−100 mg GAE/100 g. DPPH scavenging activity varied among the samples being the highest for lavender honey (IC50 = 88.2 ± 2.11 mg/mL) and the lowest for rapeseed honey (IC50 = 646 ± 8.72 mg/mL). Antibacterial activity was estimated in vitro using agar diffusion tests and measuring minimal inhibitory concentration (MIC). Among investigated bacterial strains following resistant potencies were determined: Escherichia coli > Escherichia coli ATCC 8739 > Enterococcus faecalis > Proteus mirabilis > Staphylococcus aureus > Staphylococcus epidermidis. The linden honey from Fruska Gora (MIC values of 3.12% and 6.25% against Staphylococcus aureus and Staphylococcus epidermidis, respectively) and phacelia honey (MIC values of 6.25% and 3.12% against S.Staphylococcus aureus and Staphylococcus epidermidis, respectively) showed the strongest antibacterial activity. Antiproliferative activity was evaluated using the colorimetric sulforhodamine B (SRB) assay. The highest antiproliferative activity was obtained from linden honey sample 1 (IC50MCF7 = 7.46 ± 1.18 mg/mL and IC50HeLa =12.4 ± 2.00 mg/mL) and meadow sample 2 (IC50MCF7 = 12.0 ± 0.57 mg/mL, IC50HeLa = 16.9 ± 1.54 mg/mL and IC50HT−29 = 23.7 ± 1.33 mg/mL) towards breast (MCF7), cervix (HeLa) and colon (HT-29) cancer cells. Active components other than sugars contributed to cell growth activity.
RESUMO
Many lignicolous mushroom species are used as a food supplement and may represent an alternative treatment of Alzheimer's disease (AD). This study aimed to evaluate acetylcholinesterase inhibition (AChEI) of Stereum hirsutum together with antioxidant activity (AO) and cytotoxic activity against HepG2 cells. Different extracts (water, ethanol, methanol, polysaccharide) were analyzed, with respect to their mineral composition and chemical content. Ethanol extract was the most potent in AChEI (98.44 %) and demonstrated cytotoxic activity (91.96 % at 900.00â µg/mL), while the highest AO was demonstrated for polar extracts (methanol and water) as well. These activities may be attributed to determined phenolics (hydroxybenzoic and quinic acid) and fatty acids (FA), while biflavonoid amentoflavone may be responsible for cytotoxic activity. The most prevalent FA was linoleic (40.00 %) and the domination of unsaturated FA (UFA) (71.91 %) over saturated (26.96 %) was observed. This is the first report of AChEI of S.â hirsutum extracts and first detection of amentoflavone. Due to high amount of UFA and well-expressed AChEI, this species can be considered as a potent food supplement in the palliative therapy of AD.
Assuntos
Antineoplásicos/farmacologia , Antioxidantes/farmacologia , Basidiomycota/química , Inibidores da Colinesterase/farmacologia , Ácidos Graxos/farmacologia , Fenóis/farmacologia , Acetilcolinesterase/metabolismo , Antineoplásicos/química , Antineoplásicos/isolamento & purificação , Antioxidantes/química , Antioxidantes/isolamento & purificação , Benzotiazóis/antagonistas & inibidores , Compostos de Bifenilo/antagonistas & inibidores , Sobrevivência Celular/efeitos dos fármacos , Inibidores da Colinesterase/química , Inibidores da Colinesterase/isolamento & purificação , Ensaios de Seleção de Medicamentos Antitumorais , Ácidos Graxos/química , Ácidos Graxos/isolamento & purificação , Células Hep G2 , Humanos , Fenóis/química , Fenóis/isolamento & purificação , Picratos/antagonistas & inibidores , Ácidos Sulfônicos/antagonistas & inibidoresRESUMO
In vitro acetylholinesterase (AChE) inhibitory activity of an autochthonous sample of the mushroom Coprinus comatus (encompassing fruiting body FB, mycelia M and filtrate F from the submerged cultivation) was the subject of this study. C. comatus F extract exhibited rather potent anti-AChE activity (73.0 ± 1.5%) at in liquid conditions, comparable to those of the conventional drug donepezil (80.6 ± 1.4%). Also, the same extract exhibited high anti-AChE activity (1 µg) in solid. While its FTIR spectrum indicated the presence of phenolic compounds, quercetin (28.1 µg g-1 d.w.) was found to affect the observed bioactivity (59.8 ± 0.9%). This is the first report of profound anti-AChE activity of any C. comatus extract, a medicinal mushroom that has been successfully cultivated in P.R. China, due to the demanding needs of food industry.
Assuntos
Coprinus/química , Fármacos Neuroprotetores/isolamento & purificação , Esterol Esterase/antagonistas & inibidores , Agaricales , China , Fenóis/análise , Quercetina/isolamento & purificação , Quercetina/farmacologiaRESUMO
OBJECTIVES: We recently reported the involvement of ER stress-mediated BKCa channel inhibition in homocysteine-induced coronary dilator dysfunction. In another study, we demonstrated that tetramethylpyrazine (TMP), an active ingredient of the Chinese herb Chuanxiong, possesses potent anti-ER stress capacity. The present study investigated whether TMP protects BKCa channels from homocysteine-induced inhibition and whether suppression of ER stress is a mechanism contributing to the protection. Furthermore, we explored the signaling transduction involved in TMP-conferred protection on BKCa channels. METHODS: BKCa channel-mediated relaxation was studied in porcine small coronary arteries. Expressions of BKCa channel subunits, ER stress molecules, and E3 ubiquitin ligases, as well as BKCa ubiquitination were determined in porcine coronary arterial smooth muscle cells (PCASMCs). Whole-cell BKCa currents were recorded. RESULTS: Exposure of PCASMCs to homocysteine or the chemical ER stressor tunicamycin increased the expression of ER stress molecules, which was significantly inhibited by TMP. Suppression of ER stress by TMP preserved the BKCa ß1 protein level and restored the BKCa current in PCASMCs, concomitant with an improved BKCa-mediated dilatation in coronary arteries. TMP attenuated homocysteine-induced BKCa ß1 protein ubiquitination, in which inhibition of ER stress-mediated FoxO3a activation and FoxO3a-dependent atrogin-1 and Murf-1 was involved. CONCLUSIONS: Reversal of BKCa channel inhibition via suppressing ER stress-mediated loss of ß1 subunits contributes to the protective effect of TMP against homocysteine on coronary dilator function. Inhibition of FoxO3a-dependent ubiquitin ligases is involved in TMP-conferred normalization of BKCa ß1 protein level. These results provide new mechanistic insights into the cardiovascular benefits of TMP.
Assuntos
Estresse do Retículo Endoplasmático/efeitos dos fármacos , Homocisteína/toxicidade , Subunidades beta do Canal de Potássio Ativado por Cálcio de Condutância Alta/efeitos dos fármacos , Músculo Liso Vascular/efeitos dos fármacos , Miócitos de Músculo Liso/efeitos dos fármacos , Pirazinas/farmacologia , Vasodilatação/efeitos dos fármacos , Animais , Células Cultivadas , Vasos Coronários/efeitos dos fármacos , Vasos Coronários/metabolismo , Citoproteção , Proteína Forkhead Box O3/metabolismo , Subunidades beta do Canal de Potássio Ativado por Cálcio de Condutância Alta/metabolismo , Músculo Liso Vascular/metabolismo , Miócitos de Músculo Liso/metabolismo , Proteínas Ligases SKP Culina F-Box/metabolismo , Transdução de Sinais/efeitos dos fármacos , Sus scrofa , Proteínas com Motivo Tripartido/metabolismo , UbiquitinaçãoRESUMO
BACKGROUND: The interest towards botanicals and plant extracts has strongly risen due to their numerous biological effects and ability to counteract chronic diseases development. Among these effects, chemoprevention which represents the possibility to counteract the cancerogenetic process is one of the most studied. The extracts of mushroom Meripilus giganteus (MG) (Phylum of Basidiomycota) showed to exert antimicrobic, antioxidant and antiproliferative effects. Therefore, since its effect in leukemic cell lines has not been previously evaluated, we studied its potential chemopreventive effect in Jurkat and HL-60 cell lines. METHODS: MG ethanolic extract was characterized for its antioxidant activity and scavenging effect against different radical species. Moreover, its phenolic profile was evaluated by HPLC-MS-MS analyses. Flow cytometry (FCM) analyses of Jurkat and HL-60 cells treated with MG extract (0-750 µg/mL) for 24-72 h- allowed to evaluate its cytotoxicity, pro-apoptotic and anti-proliferative effect. To better characterize MG pro-apoptotic mechanism ROS intracellular level and the gene expression level of FAS, BAX and BCL2 were also evaluated. Moreover, to assess MG extract selectivity towards cancer cells, its cytotoxicity was also evaluated in human peripheral blood lymphocytes (PBL). RESULTS: MG extract induced apoptosis in Jurkat and HL-60 cells in a dose- and time- dependent manner by increasing BAX/BCL2 ratio, reducing ROS intracellular level and inducing FAS gene expression level. In fact, reduced ROS level is known to be related to the activation of apoptosis in leukemic cells by the involvement of death receptors. MG extract also induced cell-cycle arrest in HL-60 cells. Moreover, IC50 at 24 h treatment resulted 2 times higher in PBL than in leukemic cell lines. CONCLUSIONS: Our data suggest that MG extract might be considered a promising and partially selective chemopreventive agent since it is able to modulate different mechanisms in transformed cells at concentrations lower than in non-transformed ones.
Assuntos
Apoptose/efeitos dos fármacos , Produtos Biológicos/farmacologia , Proliferação de Células/efeitos dos fármacos , Polyporales/química , Antineoplásicos/farmacologia , Etanol , Células HL-60 , Humanos , Células Jurkat , LeucemiaRESUMO
The aim of this work was to study the bioactivity of crude aqueous and ethanolic extracts of Boletus edulis prepared from caps and stipes of wild-growing basidiocarps collected from the Prijepolje region (western Serbia). The bioactivity screening included antioxidant (2,2-diphenyl-l-picrylhydrazyl [DPPH], nitric oxide, super-oxide anion*, and hydroxyl radicals and ferric-reducing antioxidant power) and antiproliferative MTT assays (human breast MCF-7 cancer cell line). In addition, all extracts were primarily characterized by ultraviolet/visible spectrophotometry to determine total phenolic and flavonoid contents. The highest anti-DPPH and anti-hydroxyl radical activity were observed in aqueous B. edulis extract from the caps (half maximal inhibitory concentration [IC50] = 50.97 µg/ mL and 2.05 µg/mL, respectively), whereas the highest anti-nitric oxide radical activity was observed in aqueous B. edulis extract from the stipes (IC50 = 10.74 µg/mL). The ethanolic extract obtained from the mushroom stipe showed higher anti-superoxide anion radical activity (IC50 = 9.84 µg/mL) and ferric-reducing antioxidant power (22.14 mg ascorbic acid equivalents/g dry weight) compared with aqueous extracts. Total phenolic content for all extracts was similar but total flavonoid content was significantly higher in the aqueous B. edulis extract from the caps (4.5 mg quercetin equivalents/g dry weight). All crude extracts showed activity against the MCF-7 cell line, with the ethanolic extract of B. edulis prepared from stipes (IC50 = 56 µg/mL) being the most potent. This is, to our knowledge, the first report of the antiproliferative effects of crude aqueous and ethanolic extracts prepared from caps and stipes of wild-growing basidiocarps of B. edulis on the human breast MCF-7 cancer cell line.
Assuntos
Antineoplásicos/farmacologia , Antioxidantes/farmacologia , Basidiomycota/química , Misturas Complexas/farmacologia , Carpóforos/química , Antineoplásicos/isolamento & purificação , Antioxidantes/isolamento & purificação , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Misturas Complexas/química , Misturas Complexas/isolamento & purificação , Flavonoides/análise , Radicais Livres/análise , Humanos , Concentração Inibidora 50 , Fenóis/análise , SérviaRESUMO
BACKGROUND: Graft spasm remains challenging in coronary artery bypass grafting (CABG). Calcium antagonists are commonly used in patients with coronary artery disease. This study investigated the inhibitory effect of third-generation dihydropyridine calcium channel antagonist benidipine on the vasoconstriction induced by various vasoconstrictors in the human internal mammary artery (IMA). METHODS: Isolated human IMA rings (N = 65, taken from 37 patients undergoing CABG) were studied in a myograph in 2 ways: the relaxing effect of benidipine on vasoconstrictor-induced precontraction by KCl and U46619 and the depressing effect of benidipine at plasma concentrations on the contraction. Enzyme-linked immunosorbent assay (ELISA) was used to measure the change of the protein related to the L-type calcium channel. RESULTS: Benidipine caused more relaxation in KCl-contracted (86.7% ± 3.3%; n = 12) than in U46619-contracted (63.8% ± 5.3%; n = 8; p < 0.001) IMA rings. Pretreatment of IMA with plasma concentrations of benidipine (-6.92 log M) significantly depressed subsequent contraction by KCl (from 17.3 ± 2.7 mN to 7.4 ± 1.2 mN; n = 6; p < 0.05) but did not significantly affect the contraction caused by U46619. Benidipine also caused a decrease of caveolin (CaV)1.2 protein content (0.55 ± 0.02 versus 0.63 ± 0.02 mg/mL; p < 0.05). CONCLUSIONS: We conclude that in human IMA, the third-generation dihydropyridine calcium channel antagonist benidipine has a potent inhibitory effect on the vasoconstriction mediated by a variety of vasoconstrictors. Use of benidipine in patients undergoing CABG may provide vasorelaxant or antispastic effects in the grafts.
Assuntos
Bloqueadores dos Canais de Cálcio/farmacologia , Di-Hidropiridinas/farmacologia , Artéria Torácica Interna/efeitos dos fármacos , Vasodilatadores/farmacologia , Ácido 15-Hidroxi-11 alfa,9 alfa-(epoximetano)prosta-5,13-dienoico/antagonistas & inibidores , Ácido 15-Hidroxi-11 alfa,9 alfa-(epoximetano)prosta-5,13-dienoico/farmacologia , Canais de Cálcio Tipo L/análise , Canais de Cálcio Tipo L/efeitos dos fármacos , Relação Dose-Resposta a Droga , Avaliação Pré-Clínica de Medicamentos , Ensaio de Imunoadsorção Enzimática , Humanos , Técnicas In Vitro , Miografia , Cloreto de Potássio/antagonistas & inibidores , Cloreto de Potássio/farmacologia , Vasoconstrição/efeitos dos fármacos , Vasoconstritores/farmacologiaRESUMO
As we previously demonstrated the role of different K(+) channels in the action of nicorandil on human saphenous vein (HSV) and human internal mammary artery (HIMA), this study aimed to analyse the contribution of the cGMP pathway in nicorandil-induced vasorelaxation and to determine the involvement of cGMP in the K(+) channel-activating effect of nicorandil. An inhibitor of soluble guanylate cyclase (GC), ODQ, significantly inhibited nicorandil-induced relaxation, while ODQ plus glibenclamide, a selective ATP-sensitive K(+) (KATP) channel inhibitor, produced a further inhibition of both vessels. In HSV, ODQ in combination with 4-aminopyridine, a blocker of voltage-gated K(+) (KV) channels, did not modify the concentration-response to nicorandil compared with ODQ, whereas in HIMA, ODQ plus iberiotoxin, a selective blocker of large-conductance Ca(2+)-activated K(+) (BKCa) channels, produced greater inhibition than ODQ alone. We showed that the cGMP pathway plays a significant role in the vasorelaxant effect of nicorandil on HSV and HIMA. It seems that nicorandil directly opens KATP channels in both vessels and BKCa channels in HIMA, although it is possible that stimulation of GC contributes to KATP channels activation in HIMA. Contrary, the activation of KV channels in HSV is probably due to GC activation and increased levels of cGMP.
Assuntos
GMP Cíclico/fisiologia , Artéria Torácica Interna/efeitos dos fármacos , Nicorandil/farmacologia , Canais de Potássio/metabolismo , Veia Safena/efeitos dos fármacos , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/fisiologia , Vasodilatação/efeitos dos fármacos , Vasodilatadores/farmacologia , Idoso , Ponte de Artéria Coronária , Guanilato Ciclase/fisiologia , Humanos , Técnicas In Vitro , Canais KATP/metabolismo , Masculino , Pessoa de Meia-Idade , Canais de Potássio Cálcio-Ativados , Canais de Potássio de Abertura Dependente da Tensão da MembranaRESUMO
INTRODUCTION: In this report, we aim to present a rare case of isolated internal iliac artery aneurysm with associated left ureteric obstruction and consequent hydronephrosis. CASE REPORT: A 66-year-old male patient was admitted for occasional pain in the lower back that appeared one month earlier. CT arteriography revealed isolated internal iliac artery (diameter 99 mm) with ureteral obstruction, hydroureter and left kidney hydronephrosis occurrence. Aneurysm was resected, after six months the patient was doing well. Bearing in mind that 77% of the patients with isolated internal iliac artery have symptoms caused by aneurysmal compression on adjacent organs, we wanted to highlight that despite the amazing expansion of endovascular procedures in the last decades, its therapeutic effect in isolated internal iliac artery's treatment is to a great extent limited since compression symptoms cannot be solved. CONCLUSION: Open surgery remains the gold standard for isolated internal iliac artery's treatment considering significant limitations of endovascular procedures due to the inability to eliminate problems caused by compression.
Assuntos
Aneurisma da Aorta Abdominal/cirurgia , Hidronefrose/cirurgia , Aneurisma Ilíaco/cirurgia , Artéria Ilíaca/cirurgia , Obstrução Ureteral/cirurgia , Idoso , Aneurisma da Aorta Abdominal/diagnóstico , Procedimentos Endovasculares/métodos , Humanos , Hidronefrose/complicações , Hidronefrose/diagnóstico , Aneurisma Ilíaco/complicações , Aneurisma Ilíaco/diagnóstico , Rim/irrigação sanguínea , Masculino , Resultado do Tratamento , Obstrução Ureteral/complicações , Obstrução Ureteral/diagnósticoRESUMO
INTRODUCTION: Acute lower limb ischemia results from thrombosis or embolization of diseased native artery or previously implanted bypass graft. When this occurs, several options are available to restore blood flow: catheter-directed thrombolysis, mechanical thrombectomy or open surgery. Fundamental reasons to apply percutaneous interventions are avoiding open procedures in high risk patients, and avoiding difficult dissection through scar tissue. CASE OUTLINE: A 67-year-old male was admitted at our Institution for critical limb ischemia. After performed angiography the diagnosis of occluded femoropopliteal graft was established. Occlusion was resolved by catheter-directed thrombolysis with plasmin. Culprit lesions were treated by angioplasty. CONCLUSION: Our patient underwent a successful thrombolysis of occluded femoropopliteal graft with locally-delivered human plasmin.
Assuntos
Artéria Femoral/cirurgia , Fibrinolisina/administração & dosagem , Oclusão de Enxerto Vascular/tratamento farmacológico , Artéria Poplítea/cirurgia , Terapia Trombolítica/métodos , Trombose , Idoso , Implante de Prótese Vascular , Artéria Femoral/diagnóstico por imagem , Artéria Femoral/transplante , Oclusão de Enxerto Vascular/diagnóstico por imagem , Humanos , Injeções Intralesionais , Isquemia/diagnóstico por imagem , Isquemia/tratamento farmacológico , Isquemia/cirurgia , Masculino , Artéria Poplítea/diagnóstico por imagem , Artéria Poplítea/transplante , Radiografia , Trombose/diagnóstico por imagem , Trombose/tratamento farmacológico , Trombose/cirurgiaRESUMO
BACKGROUND AND AIMS: Intracellular calcium regulation in endothelial cells depends on transient receptor potential channels (TRPs). Canonical TRPs (TRPCs) are now recognized as the most important Ca(2+)-permeable cation channels in vascular endothelium and TRPC3 channel is reported to play a role in vasodilation in animal vessels. However, little is known about the role of TRPCs in human arteries. We therefore tested the hypothesis that TRPCs play a role in human arteries. METHODS: Cumulative concentration-relaxation curves to acetylcholine (-11 to -4.5 log M) were established in the human internal mammary artery (IMA) rings (n = 42) taken from 28 patients undergoing coronary artery bypass grafting in precontraction induced by U46619 (-8 log M) in the absence or presence of SKF96365 (10 µmol/L) or Pyr3 (3 µmol/L). Protein expressions of TRPC3 were determined by Western blot and immunohistochemistry staining. RESULTS: The maximal relaxation induced by acetylcholine was significantly attenuated by the nonspecific cation channels inhibitor, SKF96365 (48.2 ± 3.7 vs. 66.0 ± 0.9% in control, p <0.01) or the selective TRPC3 blocker, Pyr3 (58.4 ± 2.3% vs. 67.7 ± 1.1% in control, p <0.01). Protein expression of TRPC3 was detected in human IMA. CONCLUSIONS: TRPC3 exists and plays a role in the acetylcholine-induced endothelium-dependent relaxation in the human IMA. This study suggests that TRPC3 may be a potential new target in endothelial protection in patients with endothelial dysfunction such as in patients with coronary artery disease in order to improve the long-term patency of the grafting vessels.
Assuntos
Artéria Torácica Interna/fisiologia , Canais de Cátion TRPC/fisiologia , Acetilcolina/farmacologia , Animais , Western Blotting , Bloqueadores dos Canais de Cálcio/farmacologia , Ponte de Artéria Coronária , Dimetil Sulfóxido/farmacologia , Eletromiografia , Humanos , Imidazóis/farmacologia , Imuno-Histoquímica , Técnicas In Vitro , Artéria Torácica Interna/efeitos dos fármacos , Vasodilatação/efeitos dos fármacosRESUMO
Because adrenergic contractions can contribute to the development of life-threatening spasm of coronary artery bypass graft, this study was performed to investigate the effect of adenosine 3-phosphate (ATP)-sensitive K channel (KATP) opener P1075 on contractions of isolated human saphenous vein (HSV) and human internal mammary artery (HIMA). Phasic contractions were evoked by electric field stimulation (20 Hz) and noradrenaline. The sustained contractions were evoked by phenylephrine. The presence of pore-forming Kir6.1 and Kir6.2 subunits of the KATP channels in the HIMA and only Kir6.2 in the HSV was confirmed immunomorphologically. P1075 inhibited in the HSV only, the electrical field stimulation contractions more strongly than noradrenaline contractions. In addition, the phenylephrine contractions of HSV were more sensitive to P1075 in comparison to those of HIMA. Glibenclamide, a KATP channel blocker antagonized the vasodilatation produced by P1075 in both grafts differently, because its effect was more prominent on the P1075-induced inhibition of contractions of HSV than of HIMA. We conclude that P1075 has a vasorelaxant effect and inhibited adrenergic contractions of the tested grafts. This effect is graft and vasoconstrictor selective and seems to be mediated by Kir6.1- and/or Kir6.2-containing KATP channels. Thus, P1075 can be considered as a potential drug in the prevention of graft spasm.
Assuntos
Guanidinas/farmacologia , Canais KATP/agonistas , Artéria Torácica Interna/efeitos dos fármacos , Piridinas/farmacologia , Veia Safena/efeitos dos fármacos , Vasodilatação/efeitos dos fármacos , Vasodilatadores/farmacologia , Idoso , Estimulação Elétrica , Glibureto/farmacologia , Guanidinas/antagonistas & inibidores , Humanos , Canais KATP/metabolismo , Masculino , Artéria Torácica Interna/citologia , Artéria Torácica Interna/metabolismo , Pessoa de Meia-Idade , Técnicas de Cultura de Órgãos , Especificidade de Órgãos , Concentração Osmolar , Bloqueadores dos Canais de Potássio/farmacologia , Canais de Potássio Corretores do Fluxo de Internalização/metabolismo , Subunidades Proteicas/metabolismo , Piridinas/antagonistas & inibidores , Veia Safena/citologia , Veia Safena/metabolismo , Vasoconstrição/efeitos dos fármacos , Vasodilatadores/antagonistas & inibidoresRESUMO
Resveratrol, a stilbene polyphenol found in grapes and red wine, produces vasorelaxation in both endothelium-dependent and endothelium-independent manners. The mechanisms by which resveratrol causes vasodilatation are uncertain. The aim of this study was to investigate the mechanism(s) of endothelium-independent resveratrol-induced vasorelaxation in human internal mammary artery (HIMA) obtained from male patients undergoing coronary artery bypass surgery and to clarify the contribution of different K+ channel subtypes in resveratrol action in this blood vessel. HIMA rings without endothelium were precontracted with phenylephrine. Resveratrol induced a concentration-dependent relaxation of the HIMA. A highly selective blocker of ATP-sensitive K+ channels, glibenclamide, as well as nonselective blockers of Ca2+-sensitive K+ channels, tetraethylammonium and charybdotoxin, did not block resveratrol induced relaxation of HIMA rings. 4-Aminopyridine (4-AP), non selective blocker of voltage gated K+ (KV) channels, and margatoxin that inhibits KV1.2, KV1.3, and KV1.6 channels abolished relaxation of HIMA rings induced by resveratrol. In conclusion, we have shown that resveratrol potently relaxed HIMA rings with denuded endothelium. It seems that 4-AP- and margatoxin-sensitive K+ channels located in smooth muscle of HIMA mediated this relaxation.