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4.
Rev. mex. anestesiol ; 44(1): 66-69, ene.-mar. 2021.
Article in Spanish | LILACS-Express | LILACS | ID: biblio-1347718

ABSTRACT

Resumen: Se presenta el caso de paciente masculino, de 60 años, programado para resección transuretral de próstata. Como antecedentes destacan enfermedad de Steinert e implantación de marcapasos. La enfermedad de Steinert es el antecedente principal que guiará nuestra práctica anestésica y, tras valorar el tipo de intervención prevista, se decide anestesia locorregional, dadas las potenciales complicaciones que pueden presentar estos pacientes con la anestesia general. La conducta anestésica de los pacientes con enfermedad de Steinert supone un reto para el anestesiólogo tanto por la gran cantidad de complicaciones que pueden aparecer en el intra- y en el postoperatorio, como por la baja frecuencia de esta enfermedad. Además, el estrés quirúrgico y las técnicas utilizadas pueden interferir en el curso de la enfermedad. Por todo ello, el abordaje y los cuidados intra- y postoperatorios se deben planificar y seleccionar con cuidado con el fin de obtener los mejores resultados y extremar la seguridad del paciente.


Abstract: A 60-year-old man with prostatic hypertrophy was scheduled for transurethral resection of the prostate. Steinert's disease and implantation of a pacemaker were his previous pathology. Being Steinert's disease the most relevant clinical characteristic and the type of intervention urologist has planned, we decide locoregional anesthesia technique, avoiding the potential complications that these patients may present with general anesthesia. The anesthetic management of Steinert's disease patients is a challenge for the anesthesiologist both due to the large number of complications that may appear during intra- and postoperative time as well as the low frequency of this pathology. In addition, surgical stress and the techniques we use can interfere with the course of the disease. Therefore, the approach and immediate intra-and postoperative care should be carefully planned and selected in order to obtain the best results and maximize patient safety.

6.
J Am Coll Cardiol ; 74(3): 299-311, 2019 07 23.
Article in English | MEDLINE | ID: mdl-31319912

ABSTRACT

BACKGROUND: Fulminant myocarditis (FM) is a form of acute myocarditis characterized by severe left ventricular systolic dysfunction requiring inotropes and/or mechanical circulatory support. A single-center study found that a patient with FM had better outcomes than those with acute nonfulminant myocarditis (NFM) presenting with left ventricular systolic dysfunction, but otherwise hemodynamically stable. This was recently challenged, so disagreement still exists. OBJECTIVES: This study sought to provide additional evidence on the outcome of FM and to ascertain whether patient stratification based on the main histologic subtypes can provide additional prognostic information. METHODS: A total of 220 patients (median age 42 years, 46.3% female) with histologically proven acute myocarditis (onset of symptoms <30 days) all presenting with left ventricular systolic dysfunction were included in a retrospective, international registry comprising 16 tertiary hospitals in the United States, Europe, and Japan. The main endpoint was the occurrence of cardiac death or heart transplantation within 60 days from admission and at long-term follow-up. RESULTS: Patients with FM (n = 165) had significantly higher rates of cardiac death and heart transplantation compared with those with NFM (n = 55), both at 60 days (28.0% vs. 1.8%, p = 0.0001) and at 7-year follow-up (47.7% vs. 10.4%, p < 0.0001). Using Cox multivariate analysis, the histologic subtype emerged as a further variable affecting the outcome in FM patients, with giant cell myocarditis having a significantly worse prognosis compared with eosinophilic and lymphocytic myocarditis. In a subanalysis including only adults with lymphocytic myocarditis, the main endpoints occurred more frequently in FM compared with in NFM both at 60 days (19.5% vs. 0%, p = 0.005) and at 7-year follow up (41.4% vs. 3.1%, p = 0.0004). CONCLUSIONS: This international registry confirms that patients with FM have higher rates of cardiac death and heart transplantation both in the short- and long-term compared with patients with NFM. Furthermore, we provide evidence that the histologic subtype of FM carries independent prognostic value, highlighting the need for timely endomyocardial biopsy in this condition.


Subject(s)
Myocarditis/complications , Ventricular Dysfunction, Left/complications , Acute Disease , Adult , Female , Humans , Male , Middle Aged , Myocarditis/pathology , Prognosis , Retrospective Studies , Severity of Illness Index
7.
Am J Cardiol ; 123(7): 1019-1025, 2019 04 01.
Article in English | MEDLINE | ID: mdl-30658918

ABSTRACT

Previously reported electrocardiographic (ECG) criteria to distinguish left circumflex (LCCA) and right coronary artery (RCA) occlusion in patients with acute inferior ST-segment elevation myocardial infarction (STEMI) afford a modest diagnostic accuracy. We aimed to develop a new algorithm overcoming limitations of previous studies. Clinical, ECG, and coronary angiographic data were analyzed in 230 nonselected patients with acute inferior STEMI who underwent primary percutaneous coronary intervention. A decision-tree analysis was used to develop a new ECG algorithm. The diagnostic accuracy of reported ECG criteria was reviewed. LCCA occlusion occurred in 111 cases and RCA in 119. We developed a 3-step algorithm that identified LCCA and RCA occlusion with a sensitivity of 77%, specificity of 86%, accuracy of 82%, and Youden index of 0.63. The area under the ROC curve was 0.85 and resulted 0.82 after a 10-fold cross validation. The key leads for LCCA occlusion were V3 (ST depression in V3/ST elevation in III >1.2) and V6 (ST elevation ≥0.1 mV or greater than III). The key leads for RCA occlusion were I and aVL (ST depression ≥ 0.1 mV). Fifteen of 21 reviewed studies had less than 20 cases of LCCA occlusion, only 48% performed primary percutaneous coronary intervention, and previous infarction or multivessel disease were often excluded. The diagnostic accuracy of reported ECG criteria decreased when applied to our study population. In conclusion, we report a simple and highly discriminative 3-step ECG algorithm to differentiate LCCA and RCA occlusion in an "all comers" population of patients with acute inferior STEMI. The diagnostic key ECG leads were V3 and V6 for LCCA and I and aVL for RCA occlusion.


Subject(s)
Algorithms , Coronary Occlusion/diagnosis , Coronary Vessels/diagnostic imaging , Electrocardiography/methods , Inferior Wall Myocardial Infarction/diagnosis , ST Elevation Myocardial Infarction/diagnosis , Case-Control Studies , Coronary Angiography , Coronary Occlusion/complications , Female , Follow-Up Studies , Humans , Inferior Wall Myocardial Infarction/etiology , Male , Middle Aged , Reproducibility of Results , Retrospective Studies , ST Elevation Myocardial Infarction/etiology
8.
Cardiovasc Res ; 113(8): 950-961, 2017 Jul 01.
Article in English | MEDLINE | ID: mdl-28460013

ABSTRACT

Calpains activate during myocardial ischemia-reperfusion and contribute to reperfusion injury. Studies in transgenic animals with altered calpain/calpastatin system subjected to permanent ischemia suggest that calpains are also involved in post-infarction remodelling and heart failure. AIMS: To determine whether delayed oral administration of the calpain inhibitor SNJ-1945 reduces adverse myocardial remodelling and dysfunction following transient coronary occlusion. METHODS AND RESULTS: Male Sprague-Dawley rats were subjected to 30 min of ischemia followed by 21 days of reperfusion and received the calpain inhibitor SNJ-1945 intraperitoneally at the onset of reperfusion (Acute group), orally starting after 24 h of reperfusion and for 14 days (Chronic group), or the combination of both treatments. Calpain-1 and calpain-2 protein content increased and correlated with higher calpain activity in control hearts. Administration of SNJ-1945 attenuated calpain activation, and reduced scar expansion, ventricular dilation and dysfunction in both acute and chronic groups. Acute treatment reduced infarct size in hearts reperfused for 24 h and inflammation measured after 3 days. Delayed, chronic oral administration of SNJ-1945 attenuated inflammation, cardiomyocyte hypertrophy and collagen infiltration in the non-infarcted myocardium at 21 days in correlation with increased levels of IĸB and reduced NF-ĸB activation. In cultured fibroblasts, SNJ-1945 attenuated TGF-ß1-induced fibroblast activation. CONCLUSIONS: Our data demonstrate for the first time that long-term calpain inhibition is possible with delayed oral treatment, attenuates adverse post-infarction remodelling, likely through prevention of NF-ĸB activation, and may be a promising therapeutic intervention to prevent adverse remodelling and heart failure in patients with acute myocardial infarction.


Subject(s)
Calpain/antagonists & inhibitors , Carbamates/pharmacology , Glycoproteins/pharmacology , Myocardial Infarction/drug therapy , Myocardial Reperfusion Injury/prevention & control , Myocardium/metabolism , Animals , Calcium-Binding Proteins/drug effects , Calcium-Binding Proteins/metabolism , Calpain/metabolism , Carbamates/administration & dosage , Glycoproteins/administration & dosage , Heart/drug effects , Heart/physiopathology , Male , Myocardial Infarction/metabolism , Rats, Sprague-Dawley
9.
Therap Adv Gastroenterol ; 9(4): 437-48, 2016 Jul.
Article in English | MEDLINE | ID: mdl-27366212

ABSTRACT

BACKGROUND: Susceptibility-guided therapies (SGTs) have been proposed as preferable to empirical rescue treatments after two treatment failures. The aim of this study was to perform a systematic review and meta-analysis evaluating the effectiveness and efficacy of SGT as third-line therapy. METHODS: A systematic search was performed in multiple databases. Studies reporting cure rates of Helicobacter pylori with SGT in third-line therapy were selected. A qualitative analysis describing the current evidence and a pooled mean analysis summarizing the cure rates of SGT in third-line therapy was performed. RESULTS: No randomized controlled trials or comparative studies were found. Four observational studies reported cure rates with SGT in third-line treatment, and three studies which mixed patients with second- and third-line treatment also reported cure rates with SGT. The majority of the studies included the patients when culture had been already obtained, and so the effectiveness of SGT and empirical therapy has never been compared. A pooled mean analysis including four observational studies (283 patients) showed intention-to-treat and per-protocol eradication rates with SGT of 72% (95% confidence interval 56-87%; I(2) : 92%) and 80% (95% confidence interval 71-90%; I(2) : 80%), respectively. CONCLUSIONS: SGT may be an acceptable option as rescue treatment. However, cure rates are, at best, moderate and this approach has never been compared with a well-devised empirical therapy. The evidence in favor of SGT as rescue therapy is currently insufficient to recommend its use.

10.
Basic Res Cardiol ; 111(2): 18, 2016 Mar.
Article in English | MEDLINE | ID: mdl-26924441

ABSTRACT

Although it is widely accepted that apoptosis may contribute to cell death in myocardial infarction, experimental evidence suggests that adult cardiomyocytes repress the expression of the caspase-dependent apoptotic pathway. The aim of this study was to analyze the contribution of caspase-mediated apoptosis to myocardial ischemia-reperfusion injury. Cardiac-specific caspase-3 deficient/full caspase-7-deficient mice (Casp3/7DKO) and wild type control mice (WT) were subjected to in situ ischemia by left anterior coronary artery ligation for 45 min followed by 24 h or 28 days of reperfusion. Heart function was assessed using M-mode echocardiography. Deletion of caspases did not modify neither infarct size determined by triphenyltetrazolium staining after 24 h of reperfusion (40.0 ± 5.1 % in WT vs. 36.2 ± 3.6 % in Casp3/7DKO), nor the scar area measured by pricosirius red staining after 28 days of reperfusion (41.1 ± 5.4 % in WT vs. 44.6 ± 8.7 % in Casp3/7DKO). Morphometric and echocardiographic studies performed 28 days after the ischemic insult revealed left ventricular dilation and severe cardiac dysfunction without statistically significant differences between WT and Casp3/7DKO groups. These data demonstrate that the executioner caspases-3 and -7 do not significantly contribute to cardiomyocyte death induced by transient coronary occlusion and provide the first evidence obtained in an in vivo model that argues against a relevant role of apoptosis through the canonical caspase pathway in this context.


Subject(s)
Apoptosis , Caspase 3/metabolism , Caspase 7/metabolism , Myocardial Infarction/etiology , Ventricular Remodeling , Animals , Caspase 3/genetics , Caspase 7/genetics , Female , Male , Mice, Knockout , Myocardial Infarction/enzymology , Myocardial Infarction/pathology , Myocardium/pathology
11.
J Antimicrob Chemother ; 70(9): 2447-55, 2015 Sep.
Article in English | MEDLINE | ID: mdl-26078393

ABSTRACT

BACKGROUND: The cure rate of standard triple therapy for Helicobacter pylori infection is unacceptably low. Susceptibility-guided therapies (SGTs) have been proposed as an alternative to standard empirical treatments. The aim of this study was to perform a systematic review and meta-analysis evaluating the efficacy of SGTs. METHODS: A systematic search was performed in multiple databases. Randomized controlled trials comparing cure rates of SGTs versus those of empirical therapy were selected and analysed separately for first- and second-line treatments. A meta-analysis was performed using risk ratio (RR) and number needed to treat (NNT) to measure the effect. RESULTS: Twelve studies were included in the meta-analysis. In first-line treatment, SGT was more efficacious than empirical 7-10 day triple therapy (RR 1.16, 95% CI 1.10-1.23, I (2) = 33%; NNT = 8). Most studies used a 7-10 day triple therapy and randomized the patients after endoscopy and/or culture, thus precluding the comparison of SGT versus non-invasive testing and empirical treatment in clinical practice. For second-line therapy, only four studies were found. Results were highly heterogeneous and no significant differences were found (RR 1.11, 95% CI 0.82-1.51, I (2) = 87%). CONCLUSIONS: Once endoscopy and culture have been performed, SGT is superior to empirical 7 or 10 day triple therapy for first-line treatment. Further studies are needed to evaluate the effectiveness of SGT in clinical practice, especially when compared with currently recommended first-line quadruple therapies.


Subject(s)
Anti-Bacterial Agents/pharmacology , Anti-Bacterial Agents/therapeutic use , Drug Therapy/methods , Helicobacter Infections/drug therapy , Helicobacter pylori/drug effects , Helicobacter Infections/microbiology , Helicobacter pylori/isolation & purification , Humans , Microbial Sensitivity Tests , Treatment Outcome
12.
Cardiovasc Res ; 103(4): 542-53, 2014 Sep 01.
Article in English | MEDLINE | ID: mdl-25020913

ABSTRACT

AIMS: It has been shown that sarcoplasmic reticulum calcium ATPase (SERCA) plays a critical role in reperfusion injury. Moreover, ischaemic post-conditioning (PoCo) results in protein kinase G (PKG) activation which has been proposed to modulate phospholamban (PLB) and SERCA. We assessed whether PLB phosphorylation contributes to the cardioprotective effects of PoCo. METHODS AND RESULTS: Isolated Sprague-Dawley rat hearts were submitted to 40 min of ischaemia and reperfusion with and without a PoCo protocol that reduced infarct size by 48%. Reperfusion caused a rapid phosphorylation in PLB at Ser16 and Thr17 that was delayed by PoCo. NO-independent activation of soluble guanylate cyclase (sGC) (ataciguat) and cAMP-dependent protein kinase (PKA) inhibition (KT5720) mimicked the reduction in Ser16 phosphorylation in reperfused control hearts, while in PoCo hearts the inhibitors of PKG (KT5823) and phosphodiesterase 2 (BAY-60-7550) reverted it. CaMKII activity measured by Thr287 phosphorylation was reduced in PoCo. In reperfused control hearts, inhibition of PLB phosphorylation or SERCA (thapsigargin) simulated the cardioprotective effects of PoCo. Ataciguat reduced cytosolic Ca(2+) oscillations and improved Ca(2+) recovery in cardiomyocytes subjected to anoxia-reoxygenation and infarct size by 32% in rats with 30 min of the left anterior descending coronary artery occlusion and 2 h of reperfusion. Blockade of Na(+)/Ca(2+)-exchanger (NCX; KB-R7943) impaired Ca(2+) control in cardiomyocytes and abolished cardioprotection in PoCo hearts. CONCLUSIONS: PoCo reduces SERCA activity at the onset of reperfusion by delaying PLB phosphorylation through activation of PKG and inhibition of PKA and CaMKII. This effect contributes to PoCo protection by favouring cytosolic Ca(2+) extrusion through NCX, and it may be mimicked by pharmacological stimulation of sGC.


Subject(s)
Calcium-Binding Proteins/metabolism , Calcium/metabolism , Myocardial Reperfusion Injury/metabolism , Myocytes, Cardiac/metabolism , Animals , Cyclic AMP-Dependent Protein Kinases/metabolism , Cyclic GMP-Dependent Protein Kinases/metabolism , Ischemic Postconditioning/methods , Male , Myocardial Reperfusion/methods , Phosphorylation/physiology , Rats, Sprague-Dawley
13.
J Mol Cell Cardiol ; 68: 79-88, 2014 Mar.
Article in English | MEDLINE | ID: mdl-24434643

ABSTRACT

Mitochondria play a central role in the protection conferred by ischemic preconditioning (IP) by not fully elucidated mechanisms. We investigated whether IP protects mitochondria against ischemia-reperfusion (IR) injury through mechanisms independent of cytosolic signaling. In isolated rat hearts, sublethal IR increased superoxide production and reduced complex-I- and II-mediated respiration in subsarcolemmal (SS), but not interfibrillar (IF) mitochondria. This effect of IR on mitochondrial respiration was significantly attenuated by IP. Similar results were obtained in isolated cardiac mitochondria subjected to in vitro IR. The reduction in SS mitochondrial respiration in the heart and in vitro model was paralleled by an increase in oxidized cysteine residues, which was also prevented by IP. IP was also protective in mitochondria submitted to lethal IR. The protective effect of IP against respiratory failure was unaffected by inhibition of mitochondrial KATP channels or mitochondrial permeability transition. However, IP protection was lost in mitochondria from genetically-modified animals in which connexin-43, a protein present in SS but not IF mitochondria, was replaced by connexin-32. Our results demonstrate the existence of a protective mitochondrial mechanism or "mitochondrial preconditioning" independent of cytosol that confers protection against IR-induced respiratory failure and oxidative damage, and requires connexin-43.


Subject(s)
Ischemic Preconditioning , Mitochondria, Heart/physiology , Myocardial Reperfusion Injury/prevention & control , Animals , Cell Respiration , Connexin 43/metabolism , Coronary Circulation , Cytosol/metabolism , In Vitro Techniques , Ion Channel Gating , Male , Mice , Mice, Knockout , Mitochondrial Proteins/metabolism , Myocardial Reperfusion Injury/pathology , Oxidation-Reduction , Oxidative Phosphorylation , Oxidative Stress , Peroxynitrous Acid/metabolism , Rats , Rats, Sprague-Dawley , Signal Transduction , Superoxides/metabolism
14.
J Am Heart Assoc ; 2(1): e005975, 2013 Jan 02.
Article in English | MEDLINE | ID: mdl-23525447

ABSTRACT

BACKGROUND: The cGMP/protein kinase G (PKG) pathway is involved in the cardioprotective effects of postconditioning (PoCo). Although PKG signaling in PoCo has been proposed to depend on the activation of the phosphatidylinositol 3-kinase (PI3K)/Akt cascade, recent data bring into question a causal role of reperfusion injury signaling kinase (RISK) in PoCo protection. We hypothesized that PoCo increases PKG activity by reducing oxidative stress-induced endothelial nitric oxide synthase (NOS) uncoupling at the onset of reperfusion. METHODS AND RESULTS: Isolated rat hearts were submitted to 40 minutes of ischemia and reperfusion with and without a PoCo protocol. PoCo reduced infarct size by 48% and cGMP depletion. Blockade of cGMP synthesis (1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one) and inhibition of PKG (KT5823) or NOS (l-NAME) abolished protection, but inhibition of PI3K/Akt cascade (LY294002) did not (n=5 to 7 per group). Phosphorylation of the RISK pathway was higher in PoCo hearts. However, this difference is due to increased cell death in control hearts because in hearts reperfused with the contractile inhibitor blebbistatin, a drug effective in preventing cell death at the onset of reperfusion, RISK phosphorylation increased during reperfusion without differences between control and PoCo groups. In these hearts, PoCo reduced the production of superoxide (O2(-)) and protein nitrotyrosylation and increased nitrate/nitrite levels in parallel with a significant decrease in the oxidation of tetrahydrobiopterin (BH4) and in the monomeric form of endothelial NOS. CONCLUSIONS: These results demonstrate that PoCo activates the cGMP/PKG pathway via a mechanism independent of the PI3K/Akt cascade and dependent on the reduction of O2(-) production at the onset of reperfusion, resulting in attenuated oxidation of BH4 and reduced NOS uncoupling.


Subject(s)
Cyclic GMP-Dependent Protein Kinases/metabolism , Cyclic GMP/metabolism , Ischemic Postconditioning , Myocardial Infarction/prevention & control , Myocardial Reperfusion Injury/prevention & control , Myocardium/enzymology , Nitric Oxide Synthase Type III/metabolism , Oxidative Stress , Signal Transduction , Animals , Biopterins/analogs & derivatives , Biopterins/metabolism , Cell Death , Cyclic GMP-Dependent Protein Kinases/antagonists & inhibitors , Disease Models, Animal , Enzyme Activation , Enzyme Inhibitors/pharmacology , Male , Myocardial Infarction/enzymology , Myocardial Infarction/pathology , Myocardial Reperfusion Injury/enzymology , Myocardial Reperfusion Injury/pathology , Myocardium/pathology , Nitrates/metabolism , Nitric Oxide Synthase Type III/antagonists & inhibitors , Nitrites/metabolism , Oxidative Stress/drug effects , Phosphatidylinositol 3-Kinase/metabolism , Phosphorylation , Proto-Oncogene Proteins c-akt/metabolism , Rats , Rats, Sprague-Dawley , Signal Transduction/drug effects , Superoxides/metabolism , Time Factors , Tyrosine/analogs & derivatives , Tyrosine/metabolism
15.
Cardiovasc Res ; 96(1): 23-31, 2012 Oct 01.
Article in English | MEDLINE | ID: mdl-22787134

ABSTRACT

Loss of calcium (Ca(2+)) homeostasis contributes through different mechanisms to cell death occurring during the first minutes of reperfusion. One of them is an unregulated activation of a variety of Ca(2+)-dependent enzymes, including the non-lysosomal cysteine proteases known as calpains. This review analyses the involvement of the calpain family in reperfusion-induced cardiomyocyte death. Calpains remain inactive before reperfusion due to the acidic pHi and increased ionic strength in the ischaemic myocardium. However, inappropriate calpain activation occurs during myocardial reperfusion, and subsequent proteolysis of a wide variety of proteins contributes to the development of contractile dysfunction and necrotic cell death by different mechanisms, including increased membrane fragility, further impairment of Na(+) and Ca(2+) handling, and mitochondrial dysfunction. Recent studies demonstrating that calpain inhibition contributes to the cardioprotective effects of preconditioning and postconditioning, and the beneficial effects obtained with new and more selective calpain inhibitors added at the onset of reperfusion, point to the potential cardioprotective value of therapeutic strategies designed to prevent calpain activation.


Subject(s)
Calpain/metabolism , Myocardial Ischemia/enzymology , Myocardial Reperfusion Injury/enzymology , Animals , Calcium/metabolism , Calpain/antagonists & inhibitors , Enzyme Activation , Humans
16.
Basic Res Cardiol ; 106(6): 1259-68, 2011 Nov.
Article in English | MEDLINE | ID: mdl-21959501

ABSTRACT

Mitochondrial permeability transition (MPT) is critical in cardiomyocyte death during reperfusion but it is not the only mechanism responsible for cell injury. The objectives of the study is to investigate the role of the duration of myocardial ischemia on mitochondrial integrity and cardiomyocyte death. Mitochondrial membrane potential (ΔΨm, JC-1) and MPT (calcein) were studied in cardiomyocytes from wild-type and cyclophilin D (CyD) KO mice refractory to MPT, submitted to simulated ischemia and 10 min reperfusion. Reperfusion after 15 min simulated ischemia induced a rapid recovery of ΔΨm, extreme cell shortening (contracture) and mitochondrial calcein release, and CyD ablation did not affect these changes or cell death. However, when reperfusion was performed after 25 min simulated ischemia, CyD ablation improved ΔΨm recovery and reduced calcein release and cell death (57.8 ± 4.9% vs. 77.3 ± 4.8%, P < 0.01). In a Langendorff system, CyD ablation increased infarct size after 30 min of ischemia (61.3 ± 6.4% vs. 45.3 ± 4.0%, P = 0.02) but reduced it when ischemia was prolonged to 60 min (52.8 ± 8.1% vs. 87.6 ± 3.7%, P < 0.01). NMR spectroscopy in rat hearts showed a rapid recovery of phosphocreatine after 30 min ischemia followed by a marked decay associated with contracture and LDH release, that were preventable with contractile blockade but not with cyclosporine A. In contrast, after 50 min ischemia, phosphocreatine recovery was impaired even with contractile blockade (65.2 ± 4% at 2 min), and cyclosporine A reduced contracture, LDH release and infarct size (52.1 ± 4.2% vs. 82.8 ± 3.6%, P < 0.01). In conclusion, the duration of ischemia critically determines the importance of MPT on reperfusion injury. Mechanisms other than MPT may play an important role in cell death after less severe ischemia.


Subject(s)
Mitochondrial Membrane Transport Proteins/metabolism , Myocardial Reperfusion Injury/metabolism , Myocardial Reperfusion Injury/physiopathology , Myocytes, Cardiac/metabolism , Animals , Cell Death , Peptidyl-Prolyl Isomerase F , Cyclophilins/deficiency , Magnetic Resonance Spectroscopy , Male , Membrane Potential, Mitochondrial/physiology , Mice , Mice, Knockout , Mitochondria/pathology , Mitochondrial Permeability Transition Pore , Myocardial Reperfusion Injury/pathology , Myocytes, Cardiac/pathology , Rats , Rats, Sprague-Dawley
17.
J Mol Cell Cardiol ; 50(5): 903-9, 2011 May.
Article in English | MEDLINE | ID: mdl-21362429

ABSTRACT

Ischemic postconditioning has been demonstrated to limit infarct size in patients, but its molecular mechanisms remain incompletely understood. Low intracellular pH (pHi) inhibits mitochondrial permeability transition, calpain activation and hypercontracture. Recently, delayed normalization of pHi during reperfusion has been shown to play an important role in postconditioning protection, but its relation with intracellular protective signaling cascades is unknown. The present study investigates the relation between the rate of pHi normalization and the cGMP/PKG pathway in postconditioned myocardium. In isolated Sprague-Dawley rat hearts submitted to transient ischemia both, postconditioning and acidic reperfusion protocols resulted in a similar delay in pHi recovery measured by (31)P-NMR spectroscopy (3.6±0.2min and 3.5±0.2min respectively vs. 1.4±0.2min in control group, P<0.01) and caused equivalent cardioprotection (48% and 41% of infarct reduction respectively, P<0.01), but only postconditioning increased myocardial cGMP levels (P=0.02) and activated PKG. Blockade of cGMP/PKG pathway by the addition of the guanylyl cyclase inhibitor ODQ or the PKG inhibitor KT5823 during reperfusion accelerated pHi recovery and abolished cardioprotection in postconditioned hearts, but had no effect in hearts subjected to acidic reperfusion suggesting that PKG signaling was upstream of delayed pHi normalization in postconditioned hearts. In isolated cardiomyocytes the cGMP analog 8-pCPT-cGMP delayed Na(+)/H(+)-exchange mediated pHi normalization after acidification induced by a NH(4)Cl pulse. These results demonstrate that the cGMP/PKG pathway contributes to postconditioning protection at least in part by delaying normalization of pHi during reperfusion, probably via PKG-dependent inhibition of Na(+)/H(+)-exchanger.


Subject(s)
Acidosis/metabolism , Ischemic Postconditioning , Myocardial Reperfusion Injury/metabolism , Myocardial Reperfusion Injury/physiopathology , Animals , Cells, Cultured , Cyclic GMP , Cyclic GMP-Dependent Protein Kinases , Hydrogen-Ion Concentration , L-Lactate Dehydrogenase/metabolism , Magnetic Resonance Spectroscopy , Male , Myocardial Reperfusion Injury/pathology , Myocytes, Cardiac/metabolism , Myocytes, Cardiac/pathology , Rats , Rats, Sprague-Dawley , Signal Transduction/physiology
18.
Thromb Haemost ; 104(1): 128-35, 2010 Jul.
Article in English | MEDLINE | ID: mdl-20431845

ABSTRACT

Platelets activated during experimental acute myocardial infarction (AMI) contribute to myocardial injury. This study aimed to investigate whether platelets from patients with AMI increase myocardial injury after ischaemia and reperfusion in isolated rat hearts and the modification of this effect by the P2Y12 receptor antagonist cangrelor and the glycoprotein IIb/IIIa receptor blocker abciximab. Isolated rat hearts were subjected to 40 minutes of global ischaemia and 60 minutes of reperfusion. Hearts (four simultaneous experiments per patient) were infused with platelets from nine AMI patients (seven thrombolysed, all on aspirin), untreated or incubated with 10 microM cangrelor or 5 microg/ml abciximab. Control experiments were performed using platelets from healthy volunteers and platelet-poor plasma. P-selectin expression on isolated platelets was higher in AMI patients than in controls and was not modified by the treatments. Control platelets or platelet-poor plasma did mild or no harm. In contrast, platelets from AMI patients significantly augmented myocardial injury, as demonstrated by worse left ventricular (LV) developed pressure, higher maximal LV end-diastolic pressure and coronary resistance, and greater lactate dehydrogenase release and infarct size. Both cangrelor and abciximab greatly attenuated these effects. In conclusion, activated platelets from AMI patients increase myocardial injury after ischaemia and reperfusion, and cangrelor and abciximab attenuate this effect. The results support the notion that very early antiplatelet treatment might reduce infarct size by direct effects on reperfused myocardium in these patients.


Subject(s)
Blood Platelets/drug effects , Myocardial Infarction/drug therapy , Myocardium/metabolism , P-Selectin/metabolism , Abciximab , Adenosine Monophosphate/analogs & derivatives , Adenosine Monophosphate/pharmacology , Animals , Antibodies, Monoclonal/pharmacology , Blood Platelets/metabolism , Blood Platelets/pathology , Female , Humans , Immunoglobulin Fab Fragments/pharmacology , Male , Middle Aged , Myocardial Infarction/pathology , Myocardial Infarction/physiopathology , Myocardium/pathology , P-Selectin/genetics , Platelet Activation/drug effects , Platelet Glycoprotein GPIIb-IIIa Complex/antagonists & inhibitors , Rats , Rats, Sprague-Dawley , Receptors, Purinergic P2/metabolism , Receptors, Purinergic P2Y12 , Reperfusion Injury , Ventricular Function, Left/drug effects
19.
J Mol Cell Cardiol ; 49(2): 271-9, 2010 Aug.
Article in English | MEDLINE | ID: mdl-20211186

ABSTRACT

Calpains contribute to reperfusion-induced myocardial cell death. However, it remains controversial whether its activation occurs during ischemia or reperfusion. We investigated the regulation and time-course of calpain activation secondary to transient ischemia and the efficacy of its inhibition at reperfusion as a therapeutic strategy to limit infarct size. In isolated rat hearts (Sprague-Dawley), ischemia induced a time-dependent translocation of m-calpain to the membrane that was not associated with calpain activation as assessed by proteolysis of its substrate alpha-fodrin. Translocation of calpain was dependent on Ca(2+) entry through reverse mode Na(+)/Ca(2+)-exchange and was independent of acidosis. Calpain activation occurred during reperfusion, but only after intracellular pH (pHi) normalization, and was not prevented by inhibiting its translocation during ischemia with methyl-beta-cyclodextrin. The intravenous infusion of MDL-28170 in an in vivo rat model with transient coronary occlusion during the first minutes of reperfusion resulted in a reduction of infarct size (43.9+/-3.9% vs. 60.2+/-4.7, P=0.046, n=18) and alpha-fodrin degradation. These results suggest that (1) Ca(2+)-induced calpain translocation to the membrane during ischemia is independent of its activation, (2) intracellular acidosis inhibits calpain activation during ischemia and pHi normalization allows activation upon reperfusion, and (3) calpain inhibition at the time of reperfusion appears as a potentially useful strategy to limit infarct size.


Subject(s)
Calpain/metabolism , Myocardial Reperfusion Injury/drug therapy , Myocardial Reperfusion Injury/enzymology , Animals , Calcium-Binding Proteins/metabolism , Calpain/antagonists & inhibitors , Cell Death/drug effects , Enzyme Activation/drug effects , Hemodynamics/drug effects , Hydrogen-Ion Concentration , In Vitro Techniques , Intracellular Space/drug effects , Intracellular Space/metabolism , Male , Myocardial Infarction/complications , Myocardial Infarction/pathology , Myocardial Infarction/physiopathology , Myocardial Reperfusion Injury/complications , Myocardial Reperfusion Injury/physiopathology , Myocardium/enzymology , Myocardium/pathology , Protease Inhibitors/pharmacology , Protein Transport/drug effects , Rats , Rats, Sprague-Dawley
20.
Cardiovasc Res ; 83(2): 169-78, 2009 Jul 15.
Article in English | MEDLINE | ID: mdl-19351740

ABSTRACT

Cardiomyocyte death secondary to transient ischaemia occurs mainly during the first minutes of reperfusion in the form of contraction band necrosis. Research on the mechanisms leading to sarcolemmal rupture and necrosis during initial reperfusion identified several promising pharmacological targets directed either to correct the alterations in Ca(2+) handling occurring during this period (Na(+)/H(+)-exchanger, reverse mode of Na(+)/Ca(2+)-exchanger, sarcoplasmic reticulum) or to interfere with its consequences [hypercontracture, calpain activation, and mitochondrial permeability transition pore (mPTP) opening]. However, despite the fact that pharmacological tools against some of these targets have consistently demonstrated that it is possible to reduce infarct size in experimental studies by interventions applied at the time of reperfusion, the translation of these approaches to clinical practice has failed due in part to the lack of drugs able to be tested in humans. Recently, the benefits of both post-conditioning and inhibition of mPTP have been supported by proof-of-concept trials demonstrating the clinical applicability of strategies aimed at preventing lethal reperfusion injury. These promising results should stimulate efforts to develop drugs testable in humans against known, unexploited targets involved in reperfusion injury and to identify and validate additional ones.


Subject(s)
Cardiovascular Agents/therapeutic use , Myocardial Infarction/therapy , Myocardial Reperfusion Injury/prevention & control , Myocardial Reperfusion/adverse effects , Myocardium/pathology , Animals , Apoptosis/drug effects , Calcium/metabolism , Calcium Signaling/drug effects , Cytoprotection , Gap Junctions/drug effects , Gap Junctions/pathology , Humans , Myocardial Infarction/pathology , Myocardial Reperfusion Injury/etiology , Myocardial Reperfusion Injury/metabolism , Myocardial Reperfusion Injury/pathology , Myocardium/metabolism , Necrosis , Time Factors , Treatment Outcome
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