Novel anticoagulants for stroke prevention in patients with atrial fibrillation.

Atrial fibrillation (AF) is the most common cardiac arrhythmia that can potentially result in stroke. Vitamin K antagonists (VKA) like warfarin were for many decades the only oral anticoagulants available for stroke prevention in patients with non-valvular atrial fibrillation (AF) at high risk of stroke. Recently, new oral anticoagulants (NOACS) have been introduced that act via direct inhibition of thrombin (dabigatran) or activated factor X (edoxaban, rivaroxaban and apixaban). Unlike VKAs, these anticoagulants do not require routine INR monitoring and posses favorable pharmacological properties. NOACs act rapidly, and have a stable and predictable dose-related anticoagulant effect with few clinically relevant drug-drug interactions. Phase III trials comparing these agents to warfarin for stroke prevention in patients with non-valvular AF demonstrated that they are at least as efficacious and safe as warfarin. Evolution of clinical guidelines to incorporate the new anticoagulants for stroke prevention in non-valvular AF may result in a reduction in the incidence of AF-related strokes. Safe and effective use of these new drugs in clinical practice requires understanding of their distinct pharmacological properties.

STAT1 deficiency in the heart protects against myocardial infarction by enhancing autophagy.

Previous studies have shown that the transcription factor signal transducer and activator of transcription 1 (STAT1) activation is increased in primary cardiac myocytes exposed to simulated ischaemia/reperfusion injury. This promotes apoptotic cell death by enhancing the expression of pro-apoptotic proteins. Autophagy has been demonstrated to play a cardioprotective role in the heart following myocardial infarction (MI). We therefore investigated the role of STAT1 in the intact heart subjected to MI and examined the contribution of autophagy in modulating the protective effect of STAT1 after MI injury. STAT1-deficient hearts had significantly smaller infarcts than wild-type hearts and this correlated with increased levels of autophagy shown by light chain 3 (LC3)-I/LC3-II conversion, and up-regulation of Atg12 and Beclin 1. Moreover, pre-treatment with the autophagy inhibitor 3-methyladenine reversed the cardioprotection observed in the STAT1-deficient hearts. These results reveal a new function of STAT1 in the control of autophagy and indicate a cross-talk between the cardioprotective versus the damaging effects of STAT1 in the intact heart exposed to MI injury.

Metabolic and hemodynamic features of elderly patients undergoing beating heart coronary artery bypass graft surgery.

AIM: Coronary artery bypass graft (CABG) surgery, nowadays, is increasingly performed in patients who are older and have more comorbidities than subjects operated on a decade ago. In this study, we investigated metabolic and hemodynamic features of elderly patients with single vessel coronary artery disease (CAD), undergoing beating heart coronary artery bypass graft (BHCABG) surgery. METHODS: Twenty-five elderly patients, ages 73-78 years, with isolated left anterior descending artery (LAD) disease, were enrolled and compared to a younger similar group of 25 patients, mean age 48+/-1.2 years. A single vessel left internal mammary artery (LIMA) to LAD BHCABG was performed in all patients. Duration of temporary LAD occlusion was 9.8+/-0.5 min in the elderly group, and 10+/-0.4 min in the younger group. Myocardial arterial-venous differences in glucose, lactate, and creatine phosphokinase (CPK) were performed at different time points: preoperatively in the operating room (T0); at the end of the grafting procedure (T1); and before closing the chest (T2). Left ventricular stroke work index (LVSWI), as an indicator of global function of left ventricle, were recorded at T0, T1, T2, 6 (T3) and 48 (T4) hours postoperatively. RESULTS: Preoperative glucose extraction, observed in both groups, did not augment during and after surgery. In addition, neither lactate nor CPK were released in the coronary sinus during temporary LAD occlusion and following reperfusion in either group. Similarly, no significant changes in LVSWI were observed intra- and perioperatively between the two groups. CONCLUSIONS: Cardiac metabolism, hemodynamic parameters and global left ventricular function were not affected in either group by brief LAD occlusion during BHCABG, suggesting that BHCABG is a well-tolerated surgical approach, which can be safely attempted in patients of any age.

Use of octreotide, a long-acting somatostatin analogue, in the treatment of chylothorax of idiopathic etiology.

We describe a case of chylothorax of idiopathic etiology, treated with octreotide, a long-acting somatostatin analogue. A 30-year-old man with a left supraclavicular mass, and chylothorax, initially diagnosed by outpatient thoracentesis, underwent diagnostic surgery to ascertain the etiology of the pleural effusion. Biopsies of the left supraclavicular mass, lymphatic tissue and lymph nodes were benign. Triglyceride level in the pleural fluid was 396 mg/dL, diagnostic of chylothorax. Treatment included intravenous total parenteral nutrition (TPN) and a nil per os (NPO) diet. Subsequent surgical interventions included left lung decortication and glue-mediated control of chylothorax, combined with TPN and a strict low-fat diet. Given the persistency of chylothorax, thoracic duct ligation was also performed, and octreotide subcutaneous injections were started, with dramatic resolution of pleural effusion, after 1 week of treatment, in absence of any side effects. The patient fully recovered, and no relapse has been observed during a follow-up period of over 1 year. In conclusion, octreotide showed to be a valid and safe noninvasive approach for the treatment of chylothorax, whose early clinical use may also reduce the need for surgical intervention.

Functional and clinical repercussions of myocyte apoptosis in the multifaceted damage by ischemia/reperfusion injury: old and new concepts after 10 years of contributions.

Ten years ago, the first finding of apoptotic cell death on the 'crime scene' of cardiac ischemia/reperfusion injury profoundly dismayed the scientific community. This observation jarred with the deeply rooted conviction that cardiac myocytes stoically 'break, but do not bend' in the fight against ischemia, instead of spontaneously accepting a peaceful demise for the greater good. Ten years later, a number of studies not only proved right the coexistence of necrosis and apoptosis on the ischemic battle field, but also implicated myocyte apoptosis in the pathogenesis of all the shapes and shades that cardiac ischemic injury can take on.

Urocortin protects cardiac myocytes from ischemia/reperfusion injury by attenuating calcium-insensitive phospholipase A2 gene expression.

We have used Affymetrix gene chip technology to look for changes in gene expression caused by a 24 h exposure of rat primary neonatal cardiac myocytes to the cardioprotective agent urocortin. We observed a 2.5-fold down-regulation at both the mRNA and protein levels of a specific calcium-insensitive phospholipase A2 enzyme. Levels of lysophosphatidylcholine, a toxic metabolite of phospholipase A2, were lowered by 30% in myocytes treated with urocortin for 24 h and by 50% with the irreversible iPLA2 inhibitor bromoenol lactone compared with controls. Both 4 h ischemia and ischemia followed by 24 h reperfusion caused a significant increase in lysophosphatidylcholine concentration compared with controls. When these myocytes were pretreated with urocortin, the ischemia-induced increase in lysophosphatidylcholine concentration was significantly lowered. Moreover, co-incubation of cardiac myocytes with urocortin, or the specific phospholipase A2 inhibitor bromoenol lactone, reduces the cytotoxicity produced by lysophosphatidylcholine or ischemia/reperfusion. Similarly, in the intact heart ex vivo we found that cardiac damage measured by infarct size was significantly increased when lysophoshatidylcholine was applied during ischemia, compared with ischemia alone, and that pre-treatment with both urocortin and bromoenol lactone reversed the increase in infarct size. This, to our knowledge, is the first study linking the cardioprotective effect of urocortin to a decrease in a specific enzyme protein and a subsequent decrease in the concentration of its cardiotoxic metabolite.

Quantitative assessment of cardiac myocyte apoptosis in tissue sections using the fluorescence-based tunel technique enhanced with counterstains.

Apoptosis is a distinct form of cell death, induced, for example, by ischaemia/reperfusion injury, that results in characteristic alterations in cell morphology and fate. In tissue sections, the most commonly used technique to detect apoptosis is terminal deoxynucleotidyl transferase mediated nick end labelling (TUNEL) staining which labels the ends of DNA strand breaks characteristic of the apoptotic process. However, without the employment of additional staining, TUNEL is only a qualitative procedure that gives no information about the proportion of negative cells nor the cell type undergoing apoptosis. We have utilised propidium iodide (PI) as a counterstain to visualise TUNEL negative nuclei together with anti-desmin antibody in order to assess quantitatively apoptosis in specific cell types. The procedure has been evaluated in tissue sections from isolated perfused rat hearts subjected to ischaemia and reperfusion. Hearts were cross-sectioned into four 2.5 mm thick slices which were fixed in 4% formaldehyde and embedded in paraffin. Serial sections (5 microns) were cut, dewaxed and pretreated by incubation with trypsin at 37 degrees C for 30 min. After the employment of the TUNEL assay, sections were labelled with anti-desmin antibody, counterstained with PI and finally examined by confocal fluorescent microscopy. Apoptosis was not seen in sections from hearts subjected to ischaemia alone nor in control hearts. After 35 min of ischaemia the percentages of TUNEL positive cells were very low both in myocytes (0.1%) and in non-myocytes (0.3%). In ischaemic-reperfused hearts, the number of TUNEL positive cells was only significantly higher in vascular cells (44+/-5%) and cardiac myocytes (6+/-2%). This simple method therefore allows quantification of apoptosis in myocytic and non-myocytic cells in tissue sections. Use of alternative immunohistochemical markers would permit adaptation of the method to the quantitative assessment of apoptosis in other tissues.

[Right ventricular heart failure in hyperthyroidism]. / Scompenso cardiaco destro in corso di ipertiroidismo.

Cardiovascular disorders in patients affected with hyperthyroidism are very common; the increase in the heart rate and in inotropism combines with a rise in the cardiac index towards which the reduction in peripheral resistances and an increase in the venous return to the heart contribute. The increase in myocardial excitabi1ity, caused above all by triiodothyronine, may be attended with atrial extrasystoles or even with atrial fibrillation. Congestive heart failure during hyperthyroidism, even if rare, may either reveal itself in association with pre-existent cardiopathy or to be precipitated by tachyar-rhythrmia, particu1arly, by paroxysmal atrial fibrillation. The case is described of a young woman affected with Graves' disease, presenting an ingravescent dyspnoea, in which sinusal tachycardia, the S1Q3 electrocardiographic figure and the echocardiographic reports of a right ventricu1ar overload with pulmonary hypertension and systemic venous congestion, suggest picture of acute pulmonary embolism. The isolated dysfunction of the right ventricle resolved quickly after an adequate antithyroid therapy. The oddness of presentation of Graves' disease in this case would suggest the execution of the thyroid profile for all patients with a primary diagnosis of heart failure, in order to single out hyperthyroid subjects with reversible myocardial dysfunction.

Estrogen derivative relaxes rabbit aorta via the endothelial receptor system.

BACKGROUND: It is well known that sexual hormones, in particular estrogens, may influence the cardiovascular system. Experimental and clinical studies have shown that estrogen directly or indirectly modulates the reactivity of vascular smooth muscle but at present the mechanism of action of this hormone has yet to be clarified. The aim of this study was to evaluate the vascular effects of a synthetic non-steroid estrogen, diethylstilbestrol, and the possible involvement of endothelial function. METHODS: We investigated, on aortic strips of a female rabbit, the inhibitory effects of diethylstilbestrol on the contractions induced by different spasmogenic agents, noradrenaline (10(-6) M), angiotensin II (10(-6) M), serotonin (10(-6) M), and KCl (10(-1) M). Some experiments were performed in high K+, Ca++-free solution. In some experiments endothelial function was abolished by mechanical ablation. Another series of experiments was incubated (30 min) with N(G)-monomethyl-L-arginine, which inhibits nitric oxide synthase or with tamoxifen, a specific antagonist of estrogen receptors. RESULTS: At doses from 10(-6) M to 10(-4) M, diethylstilbestrol showed an evident spasmolytic action on contractions induced by noradrenaline, angiotensin II and serotonin but no significant effect was observed on KCl spasm. The inhibitory response of diethylstilbestrol to increased vascular tone induced by noradrenaline disappeared when the endothelial function, validated by the acetylcholine test, was abolished by mechanical ablation. When tested in high K+, Ca++-free solution, diethylstilbestrol did not significantly shift the cumulative dose-response curve of calcium. In the experiments performed with N(G)-monomethyl-L-arginine, diethylstilbestrol failed to induce vasodilation suggesting that its action may be related to synthesis of nitric oxide. Moreover, in the presence of tamoxifen, diethylstilbestrol was unable to induce vasodilation. CONCLUSIONS: The early occurrence of vasodilation is in favor of a direct effect and seems to exclude a regulation of gene expression. These results suggest that estrogens may directly regulate vascular tone interacting with its specific endothelial cell receptors through the release of nitric oxide.

[Mild hypercholesterolemia. Diagnosis and prognosis]. / Ipercolesterolemia lieve. Diagnosi e prognosi.

The finding of normocholesterolaemia, characterized by plasmatic values of total cholesterol < 2 g/l, which may hide silent lipidic alterations, is not by itself sufficient to rule out the existence of cardiovascular risk. First level screening of patients exposed to atherogenic risk must begin from dosage of three basic lipidic indicators, represented by total cholesterol, triglycerides, and HDL cholesterol. By using the values of the three above-mentioned indicators and by applying Friedewald's formula, it is possible to calculate LDL cholesterol indirectly. Atherogenic risk is present when HDL cholesterol and LDL cholesterol show plasmatic concentration inferior to 0.35 g/l and superior to 1,3 g/l respectively. The European Atherosclerosis Society lists five hyperlipidaemic classes, from A to E, determined on the basis of plasmatic levels of cholesterol and triglycerides. Mild hypercolesterolaemia associated with modest atherogenic risk and which largely occurs in people and is frequently underestimated form a diagnostic point of view, contributes to cardiovascular mortality more considerably than more serious forms of hypercholesterolaemia. On the basis of this observation, there originated the programmatic proposal for the prevention of hyperlipidaemic complications, presented by the Authors.

Induction of apoptosis and Fas receptor/Fas ligand expression by ischemia/reperfusion in cardiac myocytes requires serine 727 of the STAT-1 transcription factor but not tyrosine 701.

Previously we reported that ischemia results in apoptosis and is accompanied by phosphorylation on Tyr-701 and increased expression and transcriptional activity of the signal transducer and activator of transcription-1 (STAT-1). In the present study, we show that exposure of cardiomyocytes to ischemia induced the phosphorylation of STAT-1 at another site, Ser-727. Moreover, STAT-1 is critical for the induction of Fas receptor and Fas ligand expression by ischemia/reperfusion (I/R). Transcriptional activation of Fas and FasL was dependent on Ser-727 of STAT-1 but was independent of Tyr-701. Similarly, Ser-727 but not Tyr-701 was required for enhancement of cardiomyocyte cell death by STAT-1 during I/R. In addition, inhibition of the p38 pathway prevented the induction and transcriptional activation of Fas and FasL in cardiac cells exposed to I/R, whereas inhibition of p42/p44 MAPK had no effect. Finally, I/R also induced phosphorylation of STAT-1 on Ser-727 and expression of Fas/FasL in ventricular myocytes in the intact heart ex vivo. These results indicate that Fas/FasL genes and apoptosis are activated by STAT-1 in cardiac myocytes exposed to I/R and these effects are dependent on the Ser-727 but not the Tyr-701 phosphorylation sites of STAT-1.

Ischemia-induced STAT-1 expression and activation play a critical role in cardiomyocyte apoptosis.

We show here that exposure of cardiac cells to simulated ischemia results in apoptosis and is accompanied by phosphorylation and increased expression and transcriptional activity of STAT-1. Similarly, interferon-gamma, which is known to induce STAT-1 activation, also induced apoptosis in cardiac cells. STAT-1-transfected cells were more susceptible to ischemia-induced cell death than cells transfected with a control plasmid lacking the STAT-1 coding sequence. Furthermore, an antisense STAT-1 vector reduced both ischemia- and overexpressed STAT-1-induced cell death in cardiac cells. Both STAT-1 overexpression and interferon-gamma treatment or exposure to ischemia activated the promoter of the pro-apoptotic caspase-1 gene in cardiomyocytes. Finally, ischemia/reperfusion also induced STAT-1 activation and caspase-1 processing in ventricular myocytes in the intact heart ex vivo. Immunofluorescent staining demonstrated an increase in STAT-1-positive staining in cardiomyocytes in response to ischemia/reperfusion that co-localized with terminal deoxynucleotidyl transferase dVTP nick end-labeling-positive apoptotic cells. These results suggest that STAT-1 plays a critical role in the regulation of ischemia/reperfusion-induced apoptosis in cardiac cells, acting at least in part via a caspase-1 activation-dependent pathway.