Papers by Jaime García-prieto
Cardiovascular Research, 2014
ABSTRACT Background: Beta3-adrenergic receptor (b3AR) stimulation reduces myocardial ischemia/rep... more ABSTRACT Background: Beta3-adrenergic receptor (b3AR) stimulation reduces myocardial ischemia/reperfusion injury (IRI) in vivo. The aim of this study was to assess whether this effect is exerted directly in the cardiomyocytes and to investigate the role of the mPTP in this protection. Methods: Adult isolated and HL-1 cardiomyocytes were subjected to hypoxia/reoxygenation (H/R) in the presence or absence of BRL (5μM). To study the effect on the mPTP, adult cardiomyocytes were subjected to tetramethyl-rhodamine methyl ester laser-induced oxidative stress-mediated mPTP opening in the presence or absence of BRL. WT and CyclophilinD-KO mice underwent myocardial IRI and were randomized to receive the b3AR agonist BRL37344 (BRL, 5μg/kg) or saline 5 min before reperfusion. Results: Viability evaluation in cardiomyocytes showed consistent 25% cell death reduction when treated with BRL. Western blot revealed AKT signalling pathway implication and BCL2-mediated apoptotic inhibition. Susceptibility to (mPTP) opening assay resulted in a significant delay to mPTP opening in BRL37344 (5μmol/L) treated cardiomyocytes. Finally, infarct size evaluation revealed 33% reduction in the WT treated animals, while cyclophilinD-KO mice presented same extent of infarction suggesting mPTP as a key player in BRL protective effect. Conclusion: β3AR stimulation cardioprotection appear to be directly on to the cardiomyocytes by inhibiting the opening of the mPTP and promoting anti apoptotic signalling pathways.
Journal of the American College of Cardiology, 2015
Post-ischemia/reperfusion (I/R) myocardial edema was recently shown to follow a consistent bimoda... more Post-ischemia/reperfusion (I/R) myocardial edema was recently shown to follow a consistent bimodal pattern: an initial wave of edema appears on reperfusion and dissipates at 24 h, followed by a deferred wave that initiates days after infarction, peaking at 1 week. This study examined the pathophysiology underlying this post-I/R bimodal edematous reaction. Forty instrumented pigs were assigned to different myocardial infarction protocols. Edematous reaction was evaluated by water content quantification, serial cardiac magnetic resonance T2-mapping, and histology/immunohistochemistry. The association of reperfusion with the initial wave of edema was evaluated in pigs undergoing 40-min/80-min I/R and compared with pigs undergoing 120-min ischemia with no reperfusion. The role of tissue healing in the deferred wave of edema was evaluated by comparing pigs undergoing standard 40-min/7-day I/R with animals subjected to infarction without reperfusion (chronic 7-day coronary occlusion) or receiving post-I/R high-dose steroid therapy. Characterization of post-I/R tissue changes revealed maximal interstitial edema early on reperfusion in the ischemic myocardium, with maximal content of neutrophils, macrophages, and collagen at 24 h, day 4, and day 7 post-I/R, respectively. Reperfused pigs had significantly higher myocardial water content at 120 min and T2 relaxation times on 120 min cardiac magnetic resonance than nonreperfused animals. Permanent coronary occlusion or high-dose steroid therapy significantly reduced myocardial water content on day 7 post-infarction. The dynamics of T2 relaxation times during the first post-infarction week were altered significantly in nonreperfused pigs compared with pigs undergoing regular I/R. The 2 waves of the post-I/R edematous reaction are related to different pathophysiological phenomena. Although the first wave is secondary to reperfusion, the second wave occurs mainly because of tissue healing processes.
Journal of the American College of Cardiology, 2015
Exercise has been proposed as a trigger for arrhythmogenic right ventricular cardiomyopathy (ARVC... more Exercise has been proposed as a trigger for arrhythmogenic right ventricular cardiomyopathy (ARVC) phenotype manifestation; however, research is hampered by the limited availability of animal models in which disease-associated mutations can be tested. This study evaluated the impact of exercise on ARVC cardiac manifestations in mice after adeno-associated virus (AAV)-mediated gene delivery of mutant human PKP2, which encodes the desmosomal protein plakophilin-2. We developed a new model of cardiac tissue-specific transgenic-like mice on the basis of AAV gene transfer to test the potential of a combination of a human PKP2 mutation and endurance training to trigger an ARVC-like phenotype. Stable cardiac expression of mutant PKP2 (c.2203C>T), encoding the R735X mutant protein, was achieved 4 weeks after a single AAV9-R735X intravenous injection. High-field cardiac magnetic resonance over a 10-month postinfection follow-up did not detect an overt right ventricular (RV) phenotype in nonexercised (sedentary) mice. In contrast, endurance exercise training (initiated 2 weeks after AAV9-R735X injection) resulted in clear RV dysfunction that resembled the ARVC phenotype (impaired global RV systolic function and RV regional wall motion abnormalities on cardiac magnetic resonance). At the histological level, RV samples from endurance-trained R735X-infected mice displayed connexin 43 delocalization at intercardiomyocyte gap junctions, a change not observed in sedentary mice. The introduction of the PKP2 R735X mutation into mice resulted in an exercise-dependent ARVC phenotype. The R735X mutation appears to function as a dominant-negative variant. This novel system for AAV-mediated introduction of a mutation into wild-type mice has broad potential for study of the implication of diverse mutations in complex cardiomyopathies.
Journal of the American Heart Association, 2014
Biomarkers are frequently used to estimate infarct size (IS) as an endpoint in experimental and c... more Biomarkers are frequently used to estimate infarct size (IS) as an endpoint in experimental and clinical studies. Here, we prospectively studied the impact of left ventricular (LV) hypertrophy (LVH) on biomarker release in clinical and experimental myocardial infarction (MI). ST-segment elevation myocardial infarction (STEMI) patients (n=140) were monitored for total creatine kinase (CK) and cardiac troponin I (cTnI) over 72 hours postinfarction and were examined by cardiac magnetic resonance (CMR) at 1 week and 6 months postinfarction. MI was generated in pigs with induced LVH (n=10) and in sham-operated pigs (n=8), and serial total CK and cTnI measurements were performed and CMR scans conducted at 7 days postinfarction. Regression analysis was used to study the influence of LVH on total CK and cTnI release and IS estimated by CMR (gold standard). Receiver operating characteristic (ROC) curve analysis was performed to study the discriminatory capacity of the area under the curve (AUC) of cTnI and total CK in predicting LV dysfunction. Cardiomyocyte cTnI expression was quantified in myocardial sections from LVH and sham-operated pigs. In both the clinical and experimental studies, LVH was associated with significantly higher peak and AUC of cTnI, but not with differences in total CK. ROC curves showed that the discriminatory capacity of AUC of cTnI to predict LV dysfunction was significantly worse for patients with LVH. LVH did not affect the capacity of total CK to estimate IS or LV dysfunction. Immunofluorescence analysis revealed significantly higher cTnI content in hypertrophic cardiomyocytes. Peak and AUC of cTnI both significantly overestimate IS in the presence of LVH, owing to the higher troponin content per cardiomyocyte. In the setting of LVH, cTnI release during STEMI poorly predicts postinfarction LV dysfunction. LV mass should be taken into consideration when IS or LV function are estimated by troponin release.
Cardiovascular Research, 2014
ABSTRACT Background: We have shown that pre-reperfusion metoprolol reduces infarct size in humans... more ABSTRACT Background: We have shown that pre-reperfusion metoprolol reduces infarct size in humans (METOCARD-CNIC trial). Preclinical data suggest that this strategy reduces myocardial neutrophil infiltration. Here we evaluated the potential involvement of circulating cells in the cardioprotection afforded by metoprolol. Methods: WT and b1AR-KO mice were subjected to myocardial IRI (45min/24h Ischemia/Reperfusion). Ten minutes before reperfusion, animals were randomized to receive either i.v. metoprolol or vehicle through the femoral vein. In a different experiment, b1AR-KO mice were subjected to lethal irradiation and bone marrow transplant from WT donors. Once fully recovered, animals with more than an 80% engraftment were subjected to IRI and randomized to i.v.metoprolol or vehicle. At the end of the procedure, infarct size was evaluated by TTC/Evans blue staining. Additionally, intravital microscopy was performed in the cremaster muscle of WT and b1AR-KO mice after neutrophil and platelet labeling. Results: Infarct size was 30% smaller in WT animals receiving i.v. metoprolol compared to vehicle. Conversely, metoprolol had no effect on b1KO mice. In b1KO mice transplanted with WT bone marrow, the cardioprotective phenotype of metoprolol was rescued. Metoprolol massively inhibited neutrophil-platelet interactions after TNFa challenging and this effect was absent in b1KO mice. Conclusion: Circulating cells mediates the cardioprotection afforded by i.v. metoprolol.
Arteriosclerosis, Thrombosis, and Vascular Biology, 2014
Objectives-Patients with mutations in the proprotein convertase subtilisin/kexin type 9 (PCSK9) g... more Objectives-Patients with mutations in the proprotein convertase subtilisin/kexin type 9 (PCSK9) gene have hypercholesterolemia and are at high risk of adverse cardiovascular events. We aimed to stably express the pathological human D374Y gain-of-function mutant form of PCSK9 (PCSK9 DY ) in adult wild-type mice to generate a hyperlipidemic and proatherogenic animal model, achieved with a single systemic injection with adeno-associated virus (AAV). Approach and Results-We constructed an AAV-based vector to support targeted transfer of the PCSK9 DY gene to liver.
Journal of the American College of Cardiology, 2015
other members of the CNIC animal facility and farm for outstanding animal care and support. Simon... more other members of the CNIC animal facility and farm for outstanding animal care and support. Simon Bartlett (CNIC) provided English editing.
Journal of the American College of Cardiology, 2013
The study sought to evaluate the ability of cardiac magnetic resonance (CMR) to monitor acute and... more The study sought to evaluate the ability of cardiac magnetic resonance (CMR) to monitor acute and long-term changes in pulmonary vascular resistance (PVR) noninvasively. PVR monitoring during the follow-up of patients with pulmonary hypertension (PH) and the response to vasodilator testing require invasive right heart catheterization. An experimental study in pigs was designed to evaluate the ability of CMR to monitor: 1) an acute increase in PVR generated by acute pulmonary embolization (n = 10); 2) serial changes in PVR in chronic PH (n = 22); and 3) changes in PVR during vasodilator testing in chronic PH (n = 10). CMR studies were performed with simultaneous hemodynamic assessment using a CMR-compatible Swan-Ganz catheter. Average flow velocity in the main pulmonary artery (PA) was quantified with phase contrast imaging. Pearson correlation and mixed model analysis were used to correlate changes in PVR with changes in CMR-quantified PA velocity. Additionally, PVR was estimated from CMR data (PA velocity and right ventricular ejection fraction) using a formula previously validated. Changes in PA velocity strongly and inversely correlated with acute increases in PVR induced by pulmonary embolization (r = -0.92), serial PVR fluctuations in chronic PH (r = -0.89), and acute reductions during vasodilator testing (r = -0.89, p ≤ 0.01 for all). CMR-estimated PVR showed adequate agreement with invasive PVR (mean bias -1.1 Wood units,; 95% confidence interval: -5.9 to 3.7) and changes in both indices correlated strongly (r = 0.86, p < 0.01). CMR allows for noninvasive monitoring of acute and chronic changes in PVR in PH. This capability may be valuable in the evaluation and follow-up of patients with PH.
Journal of the American College of Cardiology, 2014
Journal of the American College of Cardiology, 2014
The goal of this trial was to study the long-term effects of intravenous (IV) metoprolol administ... more The goal of this trial was to study the long-term effects of intravenous (IV) metoprolol administration before reperfusion on left ventricular (LV) function and clinical events.
Annals of the New York Academy of Sciences, 2012
The main determinant of myocardial necrosis following an acute myocardial infarction (AMI) is dur... more The main determinant of myocardial necrosis following an acute myocardial infarction (AMI) is duration of ischemia. Infarct size is a strong independent predictor of postinfarction mortality. Interventions able to protect the myocardium from death during an AMI (cardioprotection) are urgently needed. Myocardial injury associated with reperfusion (ischemia/reperfusion injury [I/R]) significantly contributes to the final necrotic size. Duration of ischemia can only be reduced by social and emergency medical services--hospital collaborative programs. However, for a given duration of ischemia, infarct size can be limited by reducing reperfusion injury. Despite the fact that several therapies have been shown to reduce I/R injury in animal models, translation to humans has been frustrating. The cost of developing new drugs able to reduce I/R injury is huge, and this is a major roadblock in the field of cardioprotection. Recent studies have proposed that old, inexpensive drugs--in human use for decades (e.g., β-blockers and cyclosporine, among others)--can reduce I/R injury when administered intravenously before coronary opening. The demonstration of such a cardioprotective effect should have a significant impact in the care of AMI patients.
Basic Research in Cardiology, 2014
Selective stimulation of β3 adrenergic-receptor (β3AR) has been shown to reduce infarct size in a... more Selective stimulation of β3 adrenergic-receptor (β3AR) has been shown to reduce infarct size in a mouse model of myocardial ischemia/reperfusion. However, its functional long-term effect and the cardioprotective mechanisms at the level of cardiomyocytes have not been elucidated, and the impact of β3AR stimulation has not been evaluated in a more translational large animal model. This study aimed at evaluating pre-perfusion administration of BRL37344 both in small and large animal models of myocardial ischemia/reperfusion. Pre-reperfusion administration of the β3AR agonist BRL37344 (5 μg/kg) reduced infarct size at 2-and 24-h reperfusion in wild-type mice. Long-term (12-weeks) left ventricular (LV) function assessed by echocardiography and cardiac magnetic resonance (CMR) was significantly improved in β3AR agonist-treated mice. Incubation with β3AR agonist (BRL37344, 7 μmol/L) significantly reduced cell death in isolated adult mouse cardiomyocytes during hypoxia/reoxygenation and decreased susceptibility to deleterious opening of the mitochondrial permeability transition pore (mPTP), via a mechanism dependent on the Akt-NO signaling pathway. Pre-reperfusion BRL37344 administration had no effect on infarct size in cyclophilin-D KO mice, further implicating mPTP in the mechanism of protection. Large-white pigs underwent percutaneous coronary ischemia/reperfusion and 3-T CMR at 7 and 45 days post-infarction. Pre-perfusion administration of BRL37344 (5 μg/kg) decreased infarct size and improved long-term LV contractile function. A single-dose administration of β3AR agonist before reperfusion decreased infarct size and resulted in a consistent and long-term improvement in cardiac function, both in small and large animal models of myocardial ischemia/reperfusion. This protection appears to be executed through inhibition of mPTP opening in cardiomyocytes.
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Papers by Jaime García-prieto