Sex-related differences in the pharmacological treatment of heart failure

Heart failure (HF) represents a leading cause of morbidity and mortality. However, HF trials highlighted many differences between men and women with HF. Thus, women represent approximately a quarter of people with HF with reduced ejection fraction (HFrEF), while they account for over half of those with HF with preserved EF (HFpEF). There are also sex-related differences (SRDs) in the pharmacokinetics, pharmacodynamics and safety profile of some guideline-recommended drugs for the treatment of HF. As compared with men, women with HFrEF are less often treated with guideline-recommended HF drugs, experience more frequent and severe adverse reactions when these drugs are prescribed at the same doses in both sexes, and recent evidence suggests that women might need lower doses than men, bringing into question which are the optimal doses of HF drugs in women and men separately. However, information on SRDs in drug efficacy and safety in patients with HFrEF is very limited due to the underrepresentation of women and the lack of sex-specific evaluations of drug efficacy and safety in HF clinical trials. As a consequence, current clinical guidelines do not provide sex-specific recommendations, even when significant differences exist, at least, in drug safety. The aim of this article is to review the SRDs in the pharmacokinetics, efficacy and safety of guideline-recommended HF drugs and to identify emerging areas of research to improve our understanding of the SRDs, because a better understanding of these differences is the first step to achieve a personalized treatment of HF in women and men

Plan de formación docente de jóvenes investigadores pre- y postdoctorales del Departamento de Farmacología y Toxicología.

Los objetivos que se han alcanzado son los siguientes: 1. Teniendo en cuenta los resultados obtenidos durante el curso 2018-19 (además de los resultados obtenidos en el curso 2017-18) los participantes han alcanzado una formación por encima de lo esperado en Farmacología habiendo asistido a una media de 57% del curso en su primer año de participación (cuando lo estipulado en el Plan de Formacion Docente es del 30%). Además, han superado un 42,3% de la materia entre su primer y segundo año con una calificación media de 8,3. 2. Los jóvenes investigadores han realizado una media de 10 horas de prácticas docentes contabilizando aquellas dedicadas a la asistencia a prácticas como oyentes, el ensayo de las prácticas con tutores y la impartición misma de las sesiones de prácticas. El número de horas está muy limitado por el bajo número de horas prácticas en las asignaturas de Farmacología del Dpto. y el elevado número de jóvenes investigadores incorporados al Dpto. 3. Con todo lo anterior, los jóvenes investigadores han alcanzado la formación en competencias docentes y las horas realizadas han sido acreditadas a las respectivas autoridades de sus becas/contratos. Su participación en la docencia práctica les permitirá en el futuro solicitar un certificado de actividades docentes emitido por las autoridades académicas de la Facultad de Medicina que avalaran su experiencia docente en solicitudes de acreditación a las diferentes figuras de profesor ante la ANECA. Además, el Dpto. de Farmacología y Toxicología ha emitido informes detallados de Aptitud Docente en Farmacología reflejando su participación en el Plan de Formación Docente del Dpto. que podrán ser consideradas en solicitudes a puestos docentes en el futuro

Efectos de los antagonistas de los receptores AT1 de la angiotensina II sobre diversas corrientes de salida de K+ cardíacas humanas

Los fármacos antagonistas de los receptores tipo 1 de la angiotensina II (ARAII) se han convertido en los útlimos años en una de las primeras opciones terpéuticas en el tratamiento de la hipertensión arterial y la insuficiencia cardíaca. El estudio multicéntrioco ELITE demostró que los enfermos con insuficiencia cardíaca que eran tratados conel losartánpresentabanuna menor incidencia de muerte súbita cardíaca que los tratados con captopril. Esta disminución de la mortalidad parecía ser consecuencia de la reducción en la dispersión del intervalo QTc del electrocardiogrma producido por losartán. Estos resultados sugerían que le losartán modificaba la velocidad de repolarización del potencial de acción cardíaco humano. Sin embargo, no existía, hasta la fecha, ningún estudio en el que se anlizaran los efectos de estos fármacos sobre corrientes iónicas cardíacas. En la presente Tesis Doctoral se han estudiado los efectos de cuatro fármacos ARAII sobre las corrientes de K generadas por canales cardíacos clonados de tejido humno. Los fármacos seleccionados fueron: el losartán, cabeza de serie del grupo. Los resultados obtenidos demuestran que los cuatro fármacos, a concentraciones del rango terapéutco, modifican las corrientes de salida de K a traveś de los canles hKv1,5, HERG,KvLQT1+minK y Kv4,3. Estas modificación se presenta en ocasiones como una disminución de la salida de K y en otros casos el fármaco produce un efecto doble, aumentando o disminuyendo la salida de K a tráves del canala dependiendo del potencial de membrana y de la concentración del fármaco. El candesartán es el fármaco más potente para bloquear los canales hKv1,5, HERG, KvLQT1+minK y Kv4,3, por el contrario el E3174 es el que mayor aumento produce de las corrientes hKv1,5 y HERG mientras que el eprosartán eran el más potente para aumentar la corriente,KvLQT1+minK . Los efectos directos producidos pro losartán E3174, esprosartán y candesartán sobre los canales de K cardíacos humanos pueden ser responsables de un posible efecto antiarrítmico independiente del bloqueo de los receptores tipo 1 de la angiostensina II

Cardiac electrophysiological effects of nitric oxide

Nitric oxide (NO) synthetized by essentially all cardiac cell types plays a key role in the regulation of cardiac function. Recent evidence shows that NO modulates the activity of cardiac ion channels implicated in the genesis of the cardiac action potential and exerts anti-arrhythmic properties under some circumstances. We review the effects of NO on cardiac ion channels and the signalling pathways, including cGMP-dependent (protein kinase G and cGMP-regulated phosphodiesterases) and cGMP-independent mechanisms (S-nitrosylation and direct effects on G proteins) and finally the role of NO in the genesis of cardiac arrhythmias during ischemia-reperfusion, heart failure, long QT syndrome, atrial fibrillation, and sudden cardiac death.Ministerio de Ciencia e InnovaciónFondo de Investigación SanitariaCentro Nacional de Investigaciones CardiovascularesLilly Foundation GrantsDepto. de Farmacología y ToxicologíaFac. de MedicinaTRUEpu

I(Kur)/Kv1.5 channel blockers for the treatment of atrial fibrillation

Atrial fibrillation (AF) is the most common sustained arrhythmia. Anti-arrhythmic drugs remain the mainstay of therapy, but the available class I and III anti-arrhythmic drugs are only moderately effective in long-term restoring/maintaining sinus rhythm (SR) and can produce potentially fatal ventricular pro-arrhythmia. In an attempt to identify safer and more effective anti-arrhythmic drugs, drug discovery efforts have focused on 'atrial selective drugs' that target cardiac ion channel(s) that are exclusively or predominantly expressed in the atria. The ultra-rapid activating delayed rectifier K(+) current (I(Kur)), carried by Kv1.5 channels, is a major repolarizing current in human atria, but seems to play no role in the ventricle. This finding offers the possibility of developing selective I(Kur) blockers to restore and maintain SR without a risk of ventricular pro-arrhythmia. Several I(Kur) blockers are now being developed but clinical data are still limited, so the precise role of these agents in the treatment of AF remains to be defined. In this review we analyze the possible advantages and disadvantages of the developmental I(Kur) blockers as they represent the first step for the development of potential atrial selective drugs for a more effective and safer treatment and prevention of AF.Depto. de Farmacología y ToxicologíaFac. de MedicinaTRUEpu

Diltiazem inhibits hKv1.5 and Kv4.3 currents at therapeutic concentrations

Abstract Objective: In the present study we examined the effects of diltiazem, an L-type Ca(2+) channel blocker widely used for the control of the ventricular rate in patients with supraventricular arrhythmias, on hKv1.5 and Kv4.3 channels that generate the cardiac ultrarapid delayed rectifier (I(Kur)) and the 4-aminopyridine sensitive transient outward (I(to)) K(+) currents, respectively. Methods: hKv1.5 and Kv4.3 channels were stably and transiently expressed in mouse fibroblast and Chinese hamster ovary cells, respectively. Currents were recorded using the whole-cell patch clamp. Results: Diltiazem (0.01 nM-500 muM) blocked hKv1.5 channels, in a frequency-dependent manner exhibiting a biphasic dose-response curve (IC(50)=4.8+/-1.5 nM and 42.3+/-3.6 muM). Diltiazem delayed the initial phase of the tail current decline and shifted the midpoint of the activation (Vh=-16.5+/-2.1 mV vs -20.4+/-2.6 mV, P or =0.1 microM, accelerated the inactivation time course. The apparent association and dissociation rate constants resulted (1.7+/-0.2) x 10(6) M(-1)s(-1) and 258.6+/-38.1 s(-1), respectively. Diltiazem, 10 nM, shifted to more negative potentials the voltage-dependence of Kv4.3 channel inactivation (Vh=-33.1+/-2.3 mV vs -38.2+/-3.5 mV, n=6, Plt;0.05) the blockade increasing at potentials at which the amount of inactivated channels increased. Conclusion: The results demonstrated for the first time that diltiazem, at therapeutic concentrations, decreased hKv1.5 and Kv4.3 currents by binding to the open and the inactivated state of the channels.Pfizer Foundation GrantsDepto. de Farmacología y ToxicologíaFac. de MedicinaTRUEpu

Spironolactone and its main metabolite canrenoic acid block hKv1.5, Kv4.3 and Kv7.1 + minK channels

Both spironolactone (SP) and its main metabolite, canrenoic acid (CA), prolong cardiac action potential duration and decrease the Kv11.1 (HERG) current. We examined the effects of SP and CA on cardiac hKv1.5, Kv4.3 and Kv7.1+minK channels that generate the human I(Kur), I(to1) and I(Ks), which contribute to the control of human cardiac action potential duration.hKv1.5 currents were recorded in stably transfected mouse fibroblasts and Kv4.3 and Kv7.1 + minK in transiently transfected Chinese hamster ovary cells using the whole-cell patch clamp. SP (1 microM) and CA (1 nM) inhibited hKv1.5 currents by 23.2 +/- 3.2 and 18.9 +/- 2.7%, respectively, shifted the midpoint of the activation curve to more negative potentials and delayed the time course of tail deactivation.SP (1 microM) and CA (1 nM) inhibited the total charge crossing the membrane through Kv4.3 channels at +50 mV by 27.1 +/- 6.4 and 27.4 +/- 5.7%, respectively, and accelerated the time course of current decay. CA, but not SP, shifted the inactivation curve to more hyperpolarised potentials (V(h)-37.0 +/- 1.8 vs -40.8 +/- 1.6 mV, n = 10, P < 0.05).SP (10 microM) and CA (1 nM) also inhibited Kv7.1 + minK currents by 38.6 +/- 2.3 and 22.1 +/- 1.4%, respectively, without modifying the voltage dependence of channel activation. SP, but not CA, slowed the time course of tail current decay.CA (1 nM) inhibited the I(Kur) (29.2 +/- 5.5%) and the I(to1) (16.1 +/- 3.9%) recorded in mouse ventricular myocytes and the I(K) (21.8 +/- 6.9%) recorded in guinea-pig ventricular myocytes.A mathematical model of human atrial action potentials demonstrated that K(+) blocking effects of CA resulted in a lengthening of action potential duration, both in normal and atrial fibrillation simulated conditions. The results demonstrated that both SP and CA directly block hKv1.5, Kv4.3 and Kv7.1 + minK channels, CA being more potent for these effects. Since peak free plasma concentrations of CA ranged between 3 and 16 nM, these results indicated that blockade of these human cardiac K(+) channels can be observed after administration of therapeutic doses of SP. Blockade of these cardiac K(+) currents, together with the antagonism of the aldosterone proarrhythmic effects produced by SP, might be highly desirable for the treatment of supraventricular arrhythmias.Comisión Interministerial de Ciencia y TecnologiaComunidad de MadridRed RECAVAPfizer FoundationDepto. de Farmacología y ToxicologíaFac. de MedicinaTRUEpu

Effects of atorvastatin and simvastatin on atrial plateau currents

Recent evidence has shown that the inhibitors of the 3-hydroxy-3-methylglutaryl coenzyme A reductase (statins) might exert antiarrhythmic effects both in experimental models and in humans. In this study we analyzed the effects of atorvastatin and simvastatin acid (SVA) on the currents responsible for the duration of the plateau of human atrial action potentials: hKv1.5, Kv4.3, and L-type Ca(2+) (I(Ca,L)). hKv1.5 and Kv4.3 currents were recorded in transfected Ltk(-) and Chinese hamster ovary cells, respectively, and I(Ca,L) in mouse ventricular myocytes, using whole-cell patch-clamp. Atorvastatin and SVA produced a concentration-dependent block of hKv1.5 channels (IC(50)=4.5+/-1.7 microM and 5.7+/-0.03 microM, respectively) and shifted the midpoint of the activation and inactivation curves to more negative potentials. Importantly, atorvastatin- and SVA-induced block was added to that produced by quinidine, a drug that blocks hKv1.5 channels by binding to their pore cavity. Atorvastatin and SVA blocked Kv4.3 channels in a concentration-dependent manner (IC(50)=13.9+/-3.6 nM and 7.0+/-0.8 microM, respectively). Both drugs accelerated the inactivation kinetics and shifted the inactivation curve to more negative potentials. SVA (10 nM), but not atorvastatin, also blocked I(Ca,L) producing a frequency-dependent block that, at 2 Hz, reached a 50.2+/-1.5%. As a consequence of these effects, at nanomolar concentrations, atorvastatin lengthened, whereas SVA shortened, the duration of mouse atrial action potentials. The results suggest that atorvastatin and SVA alter Kv1.5 and Kv4.3 channel activity following a complex mechanism that does not imply the binding of the drug to the channel pore.Comisión Interministerial de Ciencia y TecnologíaSociedad Española de CardiologíaMinisterio de Sanidad y ConsumoInstituto de Salud Carlos IIIMutua MadrileñaDepto. de Farmacología y ToxicologíaFac. de MedicinaTRUEpu

Nitric oxide inhibits Kv4.3 and human cardiac transient outward potassium current (Ito1)

Aims: Chronic atrial fibrillation (CAF) is characterized by a shortening of the plateau phase of the action potentials (AP) and a decrease in the bioavailability of nitric oxide (NO). In this study, we analysed the effects of NO on Kv4.3 (I(Kv4.3)) and on human transient outward K(+) (I(to1)) currents as well as the signalling pathways responsible for them. We also analysed the expression of NO synthase 3 (NOS3) in patients with CAF. Methods and results: I(Kv4.3) and I(to1) currents were recorded in Chinese hamster ovary cells and in human atrial and mouse ventricular dissociated myocytes using the whole-cell patch clamp. The expression of NOS3 was analysed by western blotting. AP were recorded using conventional microelectrode techniques in mouse atrial preparations. NO and NO donors inhibited I(Kv4.3) and human I(to1) in a concentration- and voltage-dependent manner (IC(50) for NO: 375.0 +/- 48 nM) as a consequence of the activation of adenylate cyclase and the subsequent activation of the cAMP-dependent protein kinase and the serine-threonine phosphatase 2A. The density of the I(to1) recorded in ventricular myocytes from wild-type (WT) and NOS3-deficient mice (NOS3(-/-)) was not significantly different. Furthermore, the duration of atrial AP repolarization in WT and NOS3(-/-) mice was not different. The increase in NO levels to 200 nM prolonged the plateau phase of the mouse atrial AP and lengthened the AP duration measured at 20 and 50% of repolarization of the human atrial CAF-remodelled AP as determined using a mathematical model. However, the expression of NOS3 was not modified in left atrial appendages from CAF patients. Conclusion: Our results suggested that the increase in the atrial NO bioavailability could partially restore the duration of the plateau phase of CAF-remodelled AP by inhibiting the I(to1) as a result of the activation of non-canonical enzymatic pathways.Ministerio de Educación y CienciaMinisterio de Sanidad y ConsumoInstituto de Salud Carlos IIISociedad Española de CardiologíaFundación LILLYDepto. de Farmacología y ToxicologíaFac. de MedicinaTRUEpu

Endocannabinoids and cannabinoid analogues block human cardiac Kv4.3 channels in a receptor-independent manner

Endocannabinoids are amides and esters of long chain fatty acids that can modulate ion channels through both receptor-dependent and receptor-independent effects. Nowadays, their effects on cardiac K(+) channels are unknown even when they can be synthesized within the heart. We have analyzed the direct effects of endocannabinoids, such as anandamide (AEA), 2-arachidonoylglycerol (2-AG), the endogenous lipid lysophosphatidylinositol, and cannabinoid analogues such as palmitoylethanolamide (PEA), and oleoylethanolamide, as well as the fatty acids from which they are endogenously synthesized, on human cardiac Kv4.3 channels, which generate the transient outward K(+) current (I(to1)). Currents were recorded in Chinese hamster ovary cells, which do not express cannabinoid receptors, by using the whole-cell patch-clamp. All these compounds inhibited I(Kv4.3) in a concentration-dependent manner, AEA and 2-AG being the most potent (IC(50) approximately 0.3-0.4 microM), while PEA was the least potent. The potency of block increased as the complexity and the number of C atoms in the fatty acyl chain increased. The effects were not mediated by modifications in the lipid order and microviscosity of the membrane and were independent of the presence of MiRP2 or DPP6 subunits in the channel complex. Indeed, effects produced by AEA were reproduced in human atrial I(to1) recorded in isolated myocytes. Moreover, AEA effects were exclusively apparent when it was applied to the external surface of the cell membrane. These results indicate that at low micromolar concentrations the endocannabinoids AEA and 2-AG directly block human cardiac Kv4.3 channels, which represent a novel molecular target for these compounds.Instituto de Salud Carlos IIIMinisterio de Educación y CienciaFundación LILLYCentro Nacional de Investigaciones CardiovascularesUniversidad Complutense de MadridSociedad Española de CardiologíaDepto. de Farmacología y ToxicologíaFac. de MedicinaTRUEpu