Mitochondrial Membrane Permeability Inhibitors in Acute Myocardial Infarction Still Awaiting Translation

Despite therapeutic advances, acute myocardial infarction (AMI) remains a leading cause of morbidity and mortality worldwide. One potential limitation of the current treatment paradigm is the lack of effective therapies to optimize reperfusion after ischemia and prevent reperfusion-mediated injury. Experimental studies indicate that this process accounts for up to 50% of the final infarct size, lending it importance as a potential target for cardioprotection. However, multiple therapeutic approaches have shown potential in pre-clinical and early phase trials but a paucity of clear clinical benefit when expanded to larger studies. Here we explore this history of trials and errors of the studies of cyclosporine A and other mitochondrial membrane permeability inhibitors, agents that appeared to have a promising pre-clinical record yet provided disappointing results in phase III clinical trials

I contratti di fiume e di lago in Piemonte. Politiche per la tutela e il mantenimento della risorsa acqua

Analisi delle politiche- Introduzione. Il contesto e gli obiettivi della ricerca #17- Parte Prima. Il Contratto di Fiume e di Lago #21- Parte Seconda. I Contratti di Fiume e di Lago in Piemonte #29- Parte Terza. L'approfondimento empirico #39- Parte Quarta. Conclusioni: apprendere dall'esperienza #79- Riferimenti bibliografici #8

Role of Interleukin-1 in Radiation-Induced Cardiomyopathy

Thoracic X-ray therapy (XRT), used in cancer treatment, is associated with increased risk of heart failure. XRT-mediated injury to the heart induces an inflammatory response leading to cardiomyopathy. The aim of this study was to determine the role of interleukin (IL)-1 in response to XRT injury to the heart and on the cardiomyopathy development in the mouse. Female mice with genetic deletion of the IL-1 receptor type I (IL-1R1 knockout mice [IL-1R1 KO]) and treatment with recombinant human IL-1 receptor antagonist anakinra, 10 mg/kg twice daily for 7 d, were used as independent approaches to determine the role of IL-1. Wild-type (wt) or IL-1R1 KO mice were treated with a single session of XRT (20 or 14 gray [Gy]). Echocardiography (before and after isoproterenol challenge) and left ventricular (LV) catheterization were performed to evaluate changes in LV dimensions and function. Masson’s trichrome was used to assess myocardial fibrosis and pericardial thickening. After 20 Gy, the contractile reserve was impaired in wt mice at d 3, and the LV ejection fraction (EF) was reduced after 4 months when compared with sham-XRT. IL-1R1 KO mice had preserved contractile reserve at 3 d and 4 months and LVEF at 4 months after XRT. Anakinra treatment for 1 d before and 7 d after XRT prevented the impairment in contractile reserve. A significant increase in LV end-diastolic pressure, associated with increased myocardial interstitial fibrosis and pericardial thickening, was observed in wt mice, as well as in IL-1R1 KO–or anakinra-treated mice. In conclusion, induction of IL-1 by XRT mediates the development of some, such as the contractile impairment, but not all aspects of the XRT-induced cardiomyopathy, such as myocardial fibrosis or pericardial thickening

Phosphodiesterase-5 inhibition and cardioprotection: potential role of hydrogen sulfide

Background Our laboratory has shown that phosphodiesterase-5 (PDE-5) inhibitors including sildenafil, vardenafil and tadalafil induce powerful protection against myocardial ischemia-reperfusion injury. We have shown that sildenafil protects through activation PKC, expression of eNOS/iNOS, protein kinase G (PKG) and opening of mitochondrial KATP (mitoKATP) channels [1]. Hydrogen sulfide (H2S) is a gaseous molecule that is produced enzymatically and exerts physiological actions in the cardiovascular system. Similar to PKG, H2S has been shown to protect the heart via opening of mitoKATP channel [2]. In the current study, we hypothesized that tadalafil, the long acting inhibitor of PDE-5 mediates cardioprotection through H2S signaling in a PKG-dependent fashion. Methods and results After baseline transthoracic echocardiography (TTE), adult ICR mice were injected i.p. with vehicle (10% DMSO) or tadalafil (1 mg/kg) with or without KT5823 (KT, PKG blocker, 1 mg/kg) or dl-propargylglycine [PAG, Cystathionine-γ-lyase (CSE, H2S-producing enzyme) blocker; 50 mg/kg] 1 h prior to coronary artery ligation for 30 min and reperfusion for 24 h, whereas C57BL-wild type and CSE-knockout mice were treated with either vehicle or tadalafil. After reperfusion, TTE was performed and hearts were collected for infarct size (IS) measurement using TTC staining. Survival was increased with tadalafil (95%) compared with control (65%, P \u3c 0.05). Infarct size was reduced with tadalafil (13.2 ± 1.7%) compared to vehicle (40.6 ± 2.5%; P \u3c 0.05). KT and PAG abolished tadalafil-induced protection (IS: 39.2 ± 1% and 51.2 ± 2.4%, respectively) similar to genetic deletion of CSE (47.2 ± 5.1%). Moreover, tadalafil preserved fractional shortening (FS: 31 ± 1.5%) compared to control (FS: 22 ± 4.8%, P \u3c 0.05). Baseline FS was 44 ± 1.7%. KT and PAG abrogated the preservation of LV function with tadalafil by decline in FS to 17 ± 1% and 23 ± 3%, respectively. Compared to vehicle, myocardial H2S production was significantly increased with tadalafil and was abolished with KT. Conclusion PKG activation with tadalafil limits myocardial infarction and preserves LV function through H2S signaling

Identification of protein-protein interactions of human HtrA1.

The human heat shock protein HtrA1, a member of the HtrA family of serine proteases, is a evolutionarily highly conserved factor which displays a widespread pattern of expression. The yeast two-hybrid technique was employed to identify new cellular proteins physically interacting with HtrA1, and thus potential targets of this serine protease. An enzymatically inactive HtrA1 point mutant, HtrA1-S328A, was generated and used as bait in a yeast two-hybrid system. Fifty-two plasmids were isolated from primary positive yeast clones. Subsequent sequencing and BLAST analysis revealed cDNAs encoding for 13 different proteins. These putative binding partners of HtrA1 appeared to be a) components of extracellular matrix; b) factors related to signal pathways, and c) unknown proteins. Among the 13 positive clones identified and reported here, it is worth of note that the interaction of HtrA1 with tubulin and collagen (extracellular matrix proteins) and with tuberin (cytoplasmic protein) is confirmed by other studies, and this further supports previous findings in which HtrA1 can be found active as an intracytoplasmic protein or as secreted protein as well

A mouse model of heart failure with preserved ejection fraction due to chronic infusion of a low subpressor dose of angiotensin II

Heart failure (HF) with preserved ejection fraction (HFpEF) is a clinical syndrome of HF symptoms associated with impaired diastolic function. Although it represents ∼50% of patients with HF, the mechanisms of disease are poorly understood, and therapies are generally ineffective in reducing HF progression. Animal models of HFpEF not due to pressure or volume overload are lacking, therefore limiting in-depth understanding of the pathophysiological mechanisms and the development of novel therapies. We hypothesize that a continuous infusion of low-dose angiotensin II (AT(II)) is sufficient to induce left ventricular (LV) diastolic dysfunction and HFpEF, without increasing blood pressure or inducing LV hypertrophy or dilatation. Osmotic pumps were implanted subcutaneously in 8-wk-old male mice assigned to the AT(II) (0.2 mg·kg(−1)·day(−1)) or volume-matched vehicle (N = 8/group) for 4 wk. We measured systolic and diastolic arterial blood pressures through a tail-cuff transducer, LV dimensions and ejection fraction through echocardiography, and LV relaxation through pulsed-wave Doppler and LV catheterization. Myocardial fibrosis and cardiomyocyte cross-sectional area were measured. AT(II) infusion had no effects on systemic arterial blood pressure. AT(II) induced significant impairment in LV diastolic function, as measured by an increase (worsening) in LV isovolumetric relaxation time, myocardial performance index, isovolumetric relaxation time constant, and LV end-diastolic pressure without altering LV dimensions, mass, or ejection fraction. Chronic infusion of low-dose AT(II) recapitulates the HFpEF phenotype in the mouse, without increasing systemic arterial blood pressure. This mouse model may provide insight into the mechanisms of HFpEF

Enhanced Interleukin-1 Activity Contributes to Exercise Intolerance in Patients with Systolic Heart Failure

Contains fulltext : 107753.pdf (publisher's version ) (Open Access)BACKGROUND: Heart failure (HF) is a complex clinical syndrome characterized by impaired cardiac function and poor exercise tolerance. Enhanced inflammation is associated with worsening outcomes in HF patients and may play a direct role in disease progression. Interleukin-1beta (IL-1beta) is a pro-inflammatory cytokine that becomes chronically elevated in HF and exerts putative negative inotropic effects. METHODS AND RESULTS: We developed a model of IL-1beta-induced left ventricular (LV) dysfunction in healthy mice that exhibited a 32% reduction in LV fractional shortening (P<0.001) and a 76% reduction in isoproterenol response (P<0.01) at 4 hours following a single dose of IL-1beta 3 mcg/kg. This phenotype was reproducible in mice injected with plasma from HF patients and fully preventable by pretreatment with IL-1 receptor antagonist (anakinra). This led to the design and conduct of a pilot clinical to test the effect of anakinra on cardiopulmonary exercise performance in patients with HF and evidence of elevated inflammatory signaling (n = 7). The median peak oxygen consumption (VO(2)) improved from 12.3 [10.0, 15.2] to 15.1 [13.7, 19.3] mL . kg(-1) . min(-1) (P = 0.016 vs. baseline) and median ventilator efficiency (V(E)/VCO(2) slope) improved from 28.1 [22.8, 31.7] to 24.9 [22.9, 28.3] (P = 0.031 vs. baseline). CONCLUSIONS: These findings suggest that IL-1beta activity contributes to poor exercise tolerance in patients with systolic HF and identifies IL-1beta blockade as a novel strategy for pharmacologic intervention. TRIAL REGISTRATION: ClinicalTrials.gov NCT01300650

Efficacy and safety of ketamine for neonatal refractory status epilepticus: case report and systematic review

BackgroundEvidence-based data on treatment of neonatal status epilepticus (SE) are scarce. We aimed to collect data on the efficacy and safety of ketamine for the treatment of neonatal SE and to assess its possible role in the treatment of neonatal SE.MethodsWe described a novel case and conducted a systematic literature review on neonatal SE treated with ketamine. The search was carried out in Pubmed, Cochrane, Clinical Trial Gov, Scopus and Web of Science.ResultsSeven published cases of neonatal SE treated with ketamine were identified and analyzed together with our novel case. Seizures typically presented during the first 24 h of life (6/8). Seizures were resistant to a mean of five antiseizure medications. Ketamine, a NMDA receptor antagonist, appeared to be safe and effective in all neonates treated. Neurologic sequelae including hypotonia and spasticity were reported for 4/5 of the surviving children (5/8). 3/5 of them were seizure free at 1–17 months of life.DiscussionNeonatal brain is more susceptible to seizures due to a shift towards increased excitation because of a paradoxical excitatory effect of GABA, a greater density of NMDA receptors and higher extracellular concentrations of glutamate. Status epilepticus and neonatal encephalopathy could further enhance these mechanisms, providing a rationale for the use of ketamine in this setting.ConclusionsKetamine in the treatment of neonatal SE showed a promising efficacy and safety profile. However, further in-depth studies and clinical trials on larger populations are needed

Alterations in the Interleukin-1/Interleukin-1 Receptor Antagonist Balance Modulate Cardiac Remodeling following Myocardial Infarction in the Mouse

Background Healing after acute myocardial infarction (AMI) is characterized by an intense inflammatory response and increased Interleukin-1 (IL-1) tissue activity. Genetically engineered mice lacking the IL-1 receptor (IL-1R1-/-, not responsive to IL-1) or the IL-1 receptor antagonist (IL-1Ra, enhanced response to IL-1) have an altered IL-1/IL-1Ra balance that we hypothesize modulates infarct healing and cardiac remodeling after AMI. Methods IL-1R1-/- and IL-1Ra-/- male mice and their correspondent wild-types (WT) were subjected to permanent coronary artery ligation or sham surgery. Infarct size (trichrome scar size), apoptotic cell death (TUNEL) and left ventricular (LV) dimensions and function (echocardiography) were measured prior to and 7 days after surgery. Results When compared with the corresponding WT, IL-1R1-/- mice had significantly smaller infarcts (−25%), less cardiomyocyte apoptosis (−50%), and reduced LV enlargement (LV end-diastolic diameter increase [LVEDD], −20%) and dysfunction (LV ejection fraction [LVEF] decrease, −50%), whereas IL-1Ra-/- mice had significantly larger infarcts (+75%), more apoptosis (5-fold increase), and more severe LV enlargement (LVEDD increase,+30%) and dysfunction (LVEF decrease, +70%)(all P values \u3c0.05). Conclusions An imbalance in IL-1/IL-1Ra signaling at the IL-1R1 level modulates the severity of cardiac remodeling after AMI in the mouse, with reduced IL-1R1 signaling providing protection and unopposed IL-1R1 signaling providing harm