RESUMEN
Levamisole is an anthelmintic drug restricted to veterinary use but is currently detected as the most widely used cocaine cutting agent in European countries. Levamisole-adulterated cocaine has been linked to acute kidney injury, marked by a decrease in glomerular filtration rate, which involves reduced renal blood flow, but data on the alteration of renovascular response produced by levamisole are scarce. Renal arteries were isolated from healthy rabbits and used for isometric tension recording in organ baths and protein analysis. We provide evidence that depending on its concentration, levamisole modulates renovascular tone by acting as a non-selective α-adrenergic receptor blocker and down-regulates α1-adrenoceptor expression. Furthermore, levamisole impairs the endothelium-dependent relaxation induced by acetylcholine without modifying endothelial nitric oxide synthase (eNOS) expression. However, exposure to superoxide dismutase (SOD) partially prevents the impairment of ACh-induced relaxation by levamisole. This response is consistent with a down-regulation of SOD1 and an up-regulation of NADPH oxidase 4 (Nox4), suggesting that endothelial NO loss is due to increased local oxidative stress. Our findings demonstrate that levamisole can interfere with renal blood flow and the coordinated response to a vasodilator stimulus, which could worsen the deleterious consequences of cocaine use.
Asunto(s)
Levamisol , Óxido Nítrico , Arteria Renal , Vasodilatación , Animales , Levamisol/farmacología , Levamisol/toxicidad , Conejos , Arteria Renal/efectos de los fármacos , Arteria Renal/metabolismo , Arteria Renal/fisiopatología , Óxido Nítrico/metabolismo , Vasodilatación/efectos de los fármacos , Masculino , Antagonistas de Receptores Adrenérgicos alfa 1/farmacología , Antagonistas de Receptores Adrenérgicos alfa 1/toxicidad , Óxido Nítrico Sintasa de Tipo III/metabolismo , Estrés Oxidativo/efectos de los fármacos , Receptores Adrenérgicos alfa 1/metabolismo , Receptores Adrenérgicos alfa 1/efectos de los fármacos , Superóxido Dismutasa/metabolismo , NADPH Oxidasa 4/metabolismo , Relación Dosis-Respuesta a Droga , Superóxido Dismutasa-1/metabolismo , Vasodilatadores/farmacologíaRESUMEN
Sodium valproate (VPA), a histone deacetylase (HDAC) inhibitor, could be a promising candidate to treat acute myocardial infarction (AMI). In this study, AMI was induced in New Zealand White rabbits by occluding the left circumflex coronary artery for 1 h, followed by reperfusion. The animals were distributed into three experimental groups: the sham-operated group (SHAM), the AMI group and the AMI + VPA group (AMI treated with VPA 500 mg/kg/day). After 5 weeks, abdominal aorta was removed and used for isometric recording of tension in organ baths or protein expression by Western blot, and plasma for the determination of nitrate/nitrite (NOx) levels by colorimetric assay. Our results indicated that AMI induced a reduction of the endothelium-dependent response to acetylcholine without modifying the endothelium-independent response to sodium nitroprusside, leading to endothelial dysfunction. VPA treatment reversed AMI-induced endothelial dysfunction and even increased NO sensitivity in vascular smooth muscle. This response was consistent with an antioxidant effect of VPA, as it was able to reverse the superoxide dismutase 1 (SOD 1) down-regulation induced by AMI. Our experiments also ruled out that the VPA mechanism was related to eNOS, iNOS, sGC and arginase expression or changes in NOx plasma levels. Therefore, we conclude that VPA improves vasodilation by increasing NO bioavailability, likely due to its antioxidant effect. Since endothelial dysfunction was closely related to AMI, VPA treatment could increase aortic blood flow, making it a potential agent in reperfusion therapy that can prevent the vascular damage.
Asunto(s)
Infarto del Miocardio , Ácido Valproico , Conejos , Animales , Ácido Valproico/farmacología , Ácido Valproico/uso terapéutico , Antioxidantes , Infarto del Miocardio/metabolismo , Aorta/metabolismo , Endotelio/metabolismo , Endotelio Vascular/metabolismoRESUMEN
BACKGROUND: Cardiac fibroblast activation protein (FAP) has an emerging role in heart failure (HF). A paradoxical reduction in its levels in pathological conditions associated with acute processes has been observed. We aimed to identify FAP cardiac tissue expression and its relationship with the main cardiac fibrosis-related signaling pathways, and to compare plasma FAP levels in acute and chronic HF patients. METHODS: Transcriptomic changes were assessed via mRNA/ncRNA-seq in left ventricle tissue from HF patients (n = 57) and controls (n = 10). Western blotting and immunohistochemistry were used to explore FAP protein levels and localization in cardiac tissue. ELISA was performed to examine plasma FAP levels in acute HF (n = 48), chronic HF (n = 15) and control samples (n = 7). RESULTS: FAP overexpression in cardiac tissue is related to the expression of molecules directly involved in cardiac fibrosis, such as POSTN, THBS4, MFAP5, COL1A2 and COL3A1 (P < 0.001), and is directly and inversely related to pro- and antifibrotic microRNAs, respectively. The observed FAP overexpression is not reflected in plasma. Circulating FAP levels were lower in acute HF patients than in controls (P < 0.05), while chronic HF patients did not show significant changes. The clinical variables analyzed, such as functional class or etiology, do not affect plasma FAP concentrations. CONCLUSIONS: We determined that in HF cardiac tissue, FAP is related to the main cardiac fibrosis signaling pathways as well as to pro- and antifibrotic microRNAs. Additionally, an acute phase of HF decreases plasma FAP levels despite the upregulation observed in cardiac tissue and regardless of other clinical conditions.
Asunto(s)
Insuficiencia Cardíaca , MicroARNs , Humanos , Regulación hacia Arriba/genética , Insuficiencia Cardíaca/metabolismo , MicroARNs/metabolismo , Fibroblastos/metabolismo , FibrosisRESUMEN
Levamisole, a veterinary anthelmintic drug, is one of the most widely used and dangerous cocaine adulterants. Like cocaine, levamisole acutely blocks noradrenaline reuptake but with much less potency, although its vascular effects are not well known. In this study, we evaluated the vascular effects of levamisole and cocaine in rabbit aortic rings used for isometric recording of tension in organ baths and protein expression by western blot. Our results indicated that levamisole (10-5-10-3 M) induced a concentration-dependent relaxation in rings precontracted with noradrenaline (10-7-3 × 10-7 M). Furthermore, it reduced the contractile response to phenylephrine (10-9-3 × 10-5 M) that was not modified by cocaine (10-5-10-4 M), and reduced α1-adrenergic receptor expression. Levamisole (10-6-10-4 M) produced a potentiation of the electrical field stimulation that was not further enhanced by the combination of both drugs. However, high concentrations of levamisole (10-3 M) abolished adrenergic neurotransmission whether administered alone or with cocaine (10-4 M). In addition, levamisole (10-5-10-3 M) also decreased endothelium-dependent relaxation to acetylcholine that was not further impaired by cocaine (10-4 M), and that was partially reversed by superoxide dismutase (SOD, 200 U/ml). These results demonstrate that levamisole has a dual effect on the adrenergic system, and its effects are independent of the presence of cocaine. At lower concentrations, it enhances the contractile sympathetic response by blocking presynaptic α2-adrenergic receptors, while at high concentrations, the effect of the antagonism of α1-adrenergic receptor prevails. In addition, levamisole induces endothelial dysfunction by reducing NO bioavailability, and this effect could be in part mediated by oxidative stress.
Asunto(s)
Cocaína , Levamisol , Adrenérgicos , Animales , Aorta/metabolismo , Cocaína/toxicidad , Levamisol/metabolismo , Levamisol/toxicidad , Norepinefrina/metabolismo , Conejos , Receptores Adrenérgicos alfa 2RESUMEN
A chronic model of acute myocardial infarction was developed to study the mechanisms involved in adverse postinfarction ventricular remodeling. In an acute myocardial infarction (AMI), the left circumflex coronary artery of New Zealand White rabbits (n = 9) was occluded by ligature for 1 h, followed by reperfusion. A specific care protocol was applied before, during, and after the intervention, and the results were compared with those of a sham operated group (n = 7). After 5 weeks, programmed stimulation and high-resolution mapping were performed on isolated and perfused hearts using the Langendorff technique. The infarct size determined by 2,3,5-triphenyltetrazolium chloride inside of the area at risk (thioflavin-S) was then determined. The area at risk was similar in both groups (54.33% (experimental infarct group) vs. 58.59% (sham group), ns). The infarct size was 73.16% as a percentage of the risk area. The experimental infarct group had a higher inducibility of ventricular arrhythmias (100% vs. 43% in the sham group, p = 0.009). A reproducible chronic experimental model of myocardial infarction is presented in which the extent and characteristics of the lesions enable the study of the vulnerability to develop ventricular arrhythmias because of the remodeling process that occurs during cardiac tissue repair.
RESUMEN
Metabolic syndrome (MetS) describes a condition associated with multiple diseases concomitantly such as diabetes, hypertension, obesity, and dyslipidemia. It has been linked with higher prevalence of cardiovascular disease, atrial fibrillation, and sudden cardiac death. One of the underlying mechanisms could be altered automaticity, which would reflect modifications of sinus node activity. These phenomena can be evaluated analyzing the components of heart rate variability (HRV). Our aim was to examine the modifications of sinus node variability in an isolated heart model of diet-induced obesity and MetS. Male NZW rabbits were randomly assigned to high-fat (HF, n = 8), control (HF-C, n = 7), high-fat, high-sucrose (HFHS, n = 9), and control (HFHS-C, n = 9) groups, fed with their respective diets during 18/28 weeks. After euthanasia, their hearts were isolated in a Langendorff system. We recorded 10-15 min of spontaneous activity. Short RR time series were analyzed, and standard HRV parameters were determined. One-way ANOVA, Kruskal-Wallis test, and bivariate correlation were used for statistical analysis (p < 0.05). We did find an increase in the complexity and irregularity of intrinsic pacemaker activity as shown by modifications of approximate entropy, sample entropy, minimum multiscale entropy, and complexity index in HFHS animals. Even though no differences were found in standard time and frequency-domain analyses, spectral heterogeneity increased in HFHS group. Animal weight and glucose intolerance were highly correlated with the modifications of intrinsic pacemaker variability. Finally, modifications of intrinsic HRV seemed to be reliant on the number of components of MetS present, given that only HFHS group showed significant changes towards an increased complexity and irregularity of intrinsic pacemaker variability.
Asunto(s)
Frecuencia Cardíaca , Síndrome Metabólico/fisiopatología , Obesidad/fisiopatología , Nodo Sinoatrial/fisiopatología , Animales , Dieta Alta en Grasa/efectos adversos , Masculino , Síndrome Metabólico/etiología , Obesidad/etiología , Conejos , Factores de TiempoRESUMEN
PURPOSE: Mechanical stretch increases sodium and calcium entry into myocytes and activates the late sodium current. GS967, a triazolopyridine derivative, is a sodium channel blocker with preferential effects on the late sodium current. The present study evaluates whether GS967 inhibits or modulates the arrhythmogenic electrophysiological effects of myocardial stretch. METHODS: Atrial and ventricular refractoriness and ventricular fibrillation modifications induced by acute stretch were studied in Langendorff-perfused rabbit hearts (n = 28) using epicardial multiple electrodes and high-resolution mapping techniques under control conditions and during the perfusion of GS967 at different concentrations (0.03, 0.1, and 0.3 µM). RESULTS: On comparing ventricular refractoriness, conduction velocity and wavelength obtained before stretch had no significant changes under each GS967 concentration while atrial refractoriness increased under GS967 0.3 µM. Under GS967, the stretch-induced changes were attenuated, and no significant differences were observed between before and during stretch. GS967 0.3 µM diminished the normal stretch-induced changes resulting in longer (less shortened) atrial refractoriness (138 ± 26 ms vs 95 ± 9 ms; p < 0.01), ventricular refractoriness (155 ± 18 ms vs 124 ± 16 ms; p < 0.01) and increments in spectral concentration (23 ± 5% vs 17 ± 2%; p < 0.01), the fifth percentile of ventricular activation intervals (46 ± 8 ms vs 31 ± 3 ms; p < 0.05), and wavelength of ventricular fibrillation (2.5 ±0.5 cm vs 1.7 ± 0.3 cm; p < 0.05) during stretch. The stretch-induced increments in dominant frequency during ventricular fibrillation (control = 38%, 0.03 µM = 33%, 0.1 µM = 33%, 0.3 µM = 14%; p < 0.01) and the stretch-induced increments in arrhythmia complexity index (control = 62%, 0.03µM = 41%, 0.1 µM = 32%, 0.3 µM = 16%; p < 0.05) progressively decreased on increasing the GS967 concentration. CONCLUSIONS: GS967 attenuates stretch-induced changes in cardiac electrophysiology.
Asunto(s)
Potenciales de Acción/efectos de los fármacos , Antiarrítmicos/farmacología , Fibrilación Atrial/prevención & control , Mecanorreceptores/efectos de los fármacos , Miocitos Cardíacos/efectos de los fármacos , Piridinas/farmacología , Bloqueadores de los Canales de Sodio/farmacología , Canales de Sodio/efectos de los fármacos , Triazoles/farmacología , Fibrilación Ventricular/prevención & control , Animales , Fibrilación Atrial/metabolismo , Fibrilación Atrial/fisiopatología , Modelos Animales de Enfermedad , Relación Dosis-Respuesta a Droga , Preparación de Corazón Aislado , Masculino , Mecanorreceptores/metabolismo , Mecanotransducción Celular/efectos de los fármacos , Miocitos Cardíacos/metabolismo , Conejos , Periodo Refractario Electrofisiológico , Canales de Sodio/metabolismo , Factores de Tiempo , Fibrilación Ventricular/metabolismo , Fibrilación Ventricular/fisiopatologíaRESUMEN
In recent years, obesity and metabolic syndrome (MetS) have become a growing problem for public health and clinical practice, given their increased prevalence due to the rise of sedentary lifestyles and unhealthy eating habits. Thanks to animal models, basic research can investigate the mechanisms underlying pathological processes such as MetS. Here, we describe the methods used to develop an experimental rabbit model of diet-induced MetS and its assessment. After a period of acclimation, animals are fed a high-fat (10% hydrogenated coconut oil and 5% lard), high-sucrose (15% sucrose dissolved in water) diet for 28 weeks. During this period, several experimental procedures were performed to evaluate the different components of MetS: morphological and blood pressure measurements, glucose tolerance determination, and the analysis of several plasma markers. At the end of the experimental period, animals developed central obesity, mild hypertension, pre-diabetes, and dyslipidemia with low HDL, high LDL, and an increase of triglyceride (TG) levels, thus reproducing the main components of human MetS. This chronic model allows new perspectives for understanding the underlying mechanisms in the progression of the disease, the detection of preclinical and clinical markers that allow the identification of patients at risk, or even the testing of new therapeutic approaches for the treatment of this complex pathology.
Asunto(s)
Dieta Alta en Grasa/métodos , Síndrome Metabólico/etiología , Animales , Modelos Animales de Enfermedad , Masculino , Síndrome Metabólico/patología , Modelos Teóricos , ConejosRESUMEN
BACKGROUND Cardioplegic arrest is a common procedure for many types of cardiac surgery, and different formulations have been proposed to enhance its cardio-protective effect. Hydrogen sulfide is an important signaling molecule that has cardio-protective properties. We therefore studied the cardio-protective effect of hydrogen sulfide in cardiac cell culture and its potential therapeutic use in combination with cardioplegia formulations. MATERIAL AND METHODS We added hydrogen sulfide donor GYY4137 to HL-1 cells to study its protective effect in nutrient starved conditions. In addition, we tested the potential use of GYY4137 when it is added into two different cardioplegia formulations: Cardi-Braun® solution and del Nido solution in an ex vivo Langendorff perfused rat hearts model. RESULTS We observed that eight-hour pre-treatment with GYY4137 significantly suppressed apoptosis in nutrient-starved HL-1 cells (28% less compared to untreated cells; p<0.05), maintained ATP content, and reduced protein synthesis. In ex vivo experiments, Cardi-Braun® and del Nido cardioplegia solutions supplemented with GYY4137 significantly reduced the pro-apoptotic protein caspase-3 content and preserved ATP content. Furthermore, GYY4137 supplemented cardioplegia solutions decreased the S-(5-adenosyl)-L-methionine/S-(adenosyl)-L-homocysteine ratio, reducing the oxidative stress in cardiac tissue. Finally, heart beating analysis revealed the preservation of the inter-beat interval and the heart rate in del Nido cardioplegia solution supplemented with GYY4137. CONCLUSIONS GYY4137 preconditioning preserved energetic state during starved conditions, attenuating the cardiomyocytes apoptosis in vitro. The addition of GYY4137 to cardioplegia solutions prevented apoptosis, ATP consumption, and oxidative stress in perfused rat hearts, restoring its electrophysiological status after cardiac arrest. These findings suggested that GYY4137 sulfide donor may improve the cardioplegia solution performance during cardiac surgery.
Asunto(s)
Apoptosis/efectos de los fármacos , Paro Cardíaco/metabolismo , Corazón/efectos de los fármacos , Sulfuro de Hidrógeno/farmacología , Miocitos Cardíacos/efectos de los fármacos , Estrés Oxidativo/efectos de los fármacos , Adenosina Trifosfato/metabolismo , Animales , Soluciones Cardiopléjicas , Caspasa 3/metabolismo , Línea Celular , Células Cultivadas , Masculino , Miocitos Cardíacos/metabolismo , Ratas , Ratas WistarRESUMEN
Pentoxifylline is a methylxanthine compound which was first filed in 1973 and registered in 1974 in the United States by Sanofi-Aventis Deustchland Gmbh for the treatment of intermittent claudication for chronic occlusive arterial disease. This methylxanthine was later discovered to be a phosphodiesterase inhibitor. Furthermore, its hemorheological properties and its function as an inhibitor of inflammatory cytokines, like TNF-α, allowed researchers to study its effects in organ ischemia and reperfusion and transplantation. Although this drug has demonstrated beneficial effects, the mechanisms by which Pentoxifylline exerts a protective effect are not fully understood. This paper focuses on reviewing the literature to define the effect of Pentoxifylline when used in liver ischemia and reperfusion injury. Our research shows different animal models in which Pentoxifylline has been used as well as different doses and time of administration, as the ideal dose and timing have not yet been ascertained in liver ischemia and reperfusion. In conclusion, Pentoxifylline has shown positive effects in liver ischemia and reperfusion injury, and the main mechanism seems to be associated with the inhibition of TNF-α.