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Gap junctions (GJ) mediate electrical coupling between cardiac myocytes, allowing the spreading of the electrical wave responsible for synchronized contraction. GJ function can be regulated by modulation of connexon densities on membranes, connexin (Cx) phosphorylation, trafficking and degradation. Recent studies have shown that adenosine (A) involves Cx43 turnover in A1 receptor-dependent manner, and dipyridamole increases GJ coupling and amount of Cx43 in endothelial cells. As the abnormalities in GJ organization and regulation have been described in diseased myocardium, the aim of the present study was to assess the regional expression of molecules involved in GJ regulation in a model of left ventricular dysfunction (LVD). For this purpose the distribution and quantitative expression of Cx43, its phosphorylated form pS368-Cx43, PKC phosphorylated substrates, RhoA and A receptors, were investigated in experimental models of right ventricular-pacing induced LVD, undergoing concomitant dipyridamole therapy or placebo, and compared with those obtained in the myocardium from sham-operated minipigs. Results demonstrate that an altered pattern of factors involved in Cx43-made GJ regulation is present in myocardium of a dysfunctioning left ventricle. Furthermore, dipyridamole treatment, which shows a mild protective role on left ventricular function, seems to act through modulating the expression and activation of these factors as confirmed by in vitro experiments on cardiomyoblastic cell line H9c2 cells., (Copyright © 2015. Published by Elsevier Ltd.)

Adenosine (ADO) is a retaliatory metabolite that is expressed in conditions of injury or stress. During these conditions ATP is released at the extracellular level and is metabolized to adenosine. For this reason, adenosine is defined as a "danger signal" for cells and organs, in addition to its important role as homeostatic regulator. Its physiological functions are mediated through interaction with four specific transmembrane receptors called ADORA1, ADORA2A, ADORA2B and ADORA3. In the lungs of mice and humans all four adenosine receptors are expressed with different roles, having pro- and anti-inflammatory roles, determining bronchoconstriction and regulating lung inflammation and airway remodeling. Adenosine receptors can also promote differentiation of lung fibroblasts into myofibroblasts, typical of the fibrotic event. This last function suggests a potential involvement of adenosine in the fibrotic lung disease processes, which are characterized by different degrees of inflammation and fibrosis. Idiopathic pulmonary fibrosis (IPF) is the pathology with the highest degree of fibrosis and is of unknown etiology and burdened by lack of effective treatments in humans., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

Since the discovery of the influence of the endocrine system on cardiac endocrine function 30 years ago, an increasing number of experimental and clinical studies have consolidated endocrine function of human heart as being a relevant component of a complex network including endocrine, nervous and immune systems. Many aspects, however, still remain unclear as to the production, secretion and peripheral degradation pathways of B- and C-type natriuretic peptides. In particular, the hypothesis that the circulating plasma pool of the pro-hormone can function as precursor of the active peptide hormone is yet to be fully demonstrated. According to recent studies, peripheral processing of circulating pro-hormone likely undergoes regulation pathways which seem to be impaired in patients with heart failure. This would open new perspectives also in the treatment of heart failure, and identify novel pharmacological targets for drugs inducing and/or modulating the maturation of the pro-hormone into active hormone., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

Apoptosis is involved in both acute and chronic loss of cardiomyocytes after myocardial infarction (MI). To date, the pathophysiological significance of an apoptotic transcriptional profile activated in the post-ischemic remodeled myocardium, in the absence of hemodynamic factors secondary to left ventricular (LV) dysfunction, still remains to be determined. The mRNA expression of pro- and anti-apoptotic factors was determined in a swine model of non-reperfused MI with preserved LV ejection fraction. The extent of cell death was evaluated by histological analysis. Male adult farm pigs with MI (n=5), induced by permanent surgical ligation of the left anterior descending coronary artery and sham-operated adult farm pigs as control (n=7) were studied. Tissue samples were collected from the border (BZ) and remote zone (RZ) of the infarcted area to identify possible regional effects. After 4 weeks post-MI, the infarct size was 13±1% of the LV wall mass in absence of contractile dysfunction. In BZ, there was increased mRNA expression of Casp-3 (BZ vs Controls: 0.51±0.15 vs 1.39±0.04, p<0.001), a significant decrease in Bcl-2 (by 63%), associated with an increase in apoptotic cells, as revealed by TUNEL staining and cleaved-Casp-3 presence. In contrast, in the RZ there was a significant reduction of pro-apoptotic factors compared to BZ (by 80% for Casp-3), in presence of scattered apoptotic cells, increased gene expression of Hsp72 (1.82±0.21 vs 1.34±0.08, p=0.037) and iNOS (1.51±0.14 vs 1.19±0.05, p<0.05) compared to control. In conclusion, the LV distribution of apoptotic transcriptional profile revealed that apoptotic cell death is highly detectable in BZ, possibly explaining the local abnormalities of myocardial cell survival in a porcine model of MI with normal overall function., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

The role of myocardial apoptosis during the development of heart failure (HF), in the absence of coronary artery stenosis, is still debated. The aim of the study was to evaluate whether (similar to functional impairment) the activation of myocardial apoptosis follows a regional pattern in an established model of pacing-induced HF. HF was induced in adult male minipigs by rapid and sustained left ventricular (LV) epicardial pacing (n=8; n=5 healthy controls). Progressive regional derangement of the contractile function and perfusion was assessed by magnetic resonance imaging as LV end-systolic wall thickening (LVESWT) and relative upslope of signal intensity (LVRUSI, %) in the anterior/anterior-lateral (pacing site, PS) and infero-septal LV region (opposite site, OS). LV tissue from PS and OS was analyzed for biomarkers of cell apoptosis and injury. After 21 days of LV pacing, LVESWT was lower in the PS compared to OS (7.6±3.7 vs 24.16±3.6%, p<0.05), and LV ejection fraction was 24.0±3.7 (p<0.05 vs control). The mRNA expression of caspase (Casp)-3 was significantly higher in the PS of HF hearts than in controls (1.28±0.125 vs 0.82±0.10), but not Casp-9. Bcl-2 and Hsp72 expression was significantly increased in PS compared to control (0.90±0.60 vs 0.63±0.033; 0.72±0.10 vs 0.28±0.098), in the presence of a TNF-α level increased by 50.7%. The regional myocardial apoptotic index, assessed by TUNEL, was unchanged in HF. In conclusion, the activators and inhibitors of cell apoptosis are equally expressed without affecting the survival of cardiomyocytes and the magnitude of regional myocardial dysfunction during development of non-ischemic HF., (Copyright © 2010 Elsevier Ltd. All rights reserved.)

In humans, the Apelin gene is located on chromosome Xq25-26.1 and it encodes a 77-aminoacid prepropeptide. Considerable sequence homology exists across different mammalian species. Apelin is emerging as an important regulator of cardiovascular homeostasis but, at present, few data from humans are available and further studies are necessary to better define its role in cardiovascular pathophysiology. The role and function of Apelin in cardiovascular system could be reliably investigated in experimental models devoid of confounding effects reflecting only the natural history of the disease. The pig constitutes a model largely used in experimental pathology where it has a central role in "in vivo" clinical settings. Sus Scrofa genoma is not completely sequenced and Apelin gene is still lacking. Aim of this study was to sequence the Apelin in Sus Scrofa for future applications to molecular biology studies. Using the guanidinium thyocyanate-phenol-chloroform method, we extracted total RNA from samples obtained from heart of mouse and from atrium and ventricle of normal pigs. Pig Apelin mRNA was sequenced using polymerase chain reaction primers designed from mouse consensus sequences. A partial sequence of Sus Scrofa Apelin mRNA, 1-201 pb, was submitted to GenBank (accession number FJ362603). The bands obtained from pig cardiac tissue shared a 99% sequence identity with Mus musculus and 90% with Rattus norvegicus. The knowledge of Apelin sequence can be an useful starting point for future studies devoted to better understand the possible alterations of Apelin mRNA expression in different cardiac diseases.