Myocardial substrate metabolism in the normal and failing heart

The alterations in myocardial energy substrate metabolism that occur in heart failure, and the causes and consequences of these abnormalities, are poorly understood. There is evidence to suggest that impaired substrate metabolism contributes to contractile dysfunction and to the progressive left ventricular remodeling that are characteristic of the heart failure state. The general concept that has recently emerged is that myocardial substrate selection is relatively normal during the early stages of heart failure; however, in the advanced stages there is a downregulation in fatty acid oxidation, increased glycolysis and glucose oxidation, reduced respiratory chain activity, and an impaired reserve for mitochondrial oxidative flux. This review discusses 1) the metabolic changes that occur in chronic heart failure, with emphasis on the mechanisms that regulate the changes in the expression of metabolic genes and the function of metabolic pathways; 2) the consequences of these metabolic changes on cardiac function; 3) the role of changes in myocardial substrate metabolism on ventricular remodeling and disease progression; and 4) the therapeutic potential of acute and long-term manipulation of cardiac substrate metabolism in heart failure

Cardiac endocrine function is an essential component of the homeostatic regulation network: physiological and clinical implications

The discovery of cardiac natriuretic hormones required a profound revision of the concept of heart function. The heart should no longer be considered only as a pump, but rather as a multi-functional and interactive organ, part of a complex network and active component of the integrated systems of the body. In the present review, we will first consider the cross-talk between endocrine and contractile function of the heart. Then, based on the existing literature, we will propose the hypothesis that cardiac endocrine function is an essential component of the integrated systems of the body and thus plays a pivotal role in fluid, electrolyte and hemodynamic homeostasis. We will highlight those studies indicating how alterations in cardiac endocrine function can better explain the pathophysiology of cardiovascular diseases and in particular of heart failure, in which several target organs develop a resistance to the biological action of cardiac natriuretic peptides. Finally, we will emphasize the concept that a complete knowledge of the cardiac endocrine function and of its relation with other neurohormonal regulatory systems of the body is crucial to correctly interpret changes in circulating natriuretic hormones, especially the brain natriuretic peptide

Evaluation of the expression of transcripts coding for CNP and for its specific receptor, NPR-B, by Real Time PCR in cardiac tissue of normal and heart failure animals

Purpose: Higher plasma levels and a cardiac production of C-type natriuretic peptide (CNP) were recently observed in patients with chronic heart failure (HF), but its cellular source and possible difference between atrium and ventricle expression are so far lacking. Aim of this study was to evaluate the expression of transcripts coding for CNP and for its specific receptor, NPR-B, in cardiac tissue (right and left atrium and ventricle) of normal and CHF animals. CNP tissue levels were also determined in cardiac extracts. Methods: Adult male minipigs (n=5) were chronically instrumented with a unipolar pacemaker connected to the anterior left ventricular (LV) wall. HF was induced by rapid pacing (180 beats/min) for 4 weeks. End-stage HF occurred at 24?2 days of pacing when the LV end-diastolic pressure was !25 mmHg. As control, we studied 5 adult male minipigs. At 4 weeks, myocardial samples were collected. Both CNP mRNA and proteins were extracted from a same sample with the method of phenol/guanidine-thiocyanate/chloroform. Tissue CNP levels were determined by a radioimmunoassay after a preliminary extraction on Sep-Pak C18, while the expression of mRNA coding for CNP and NPR-B in myocardial tissue (n=40) by Real Time reverse transcriptase-polymerase chain reaction (PCR) with DDCt method. As overall control, a parallel Real Time-PCR assay for BNP mRNA expression was carried out in the same samples. Real Time-PCR analysis was performed using an automated sequence instrument (7900HT Fast, Applied Biosystems) for the real-time monitoring of nucleic acid green dye fluorescence (SYBR Green I). Results: As to myocardial extracts, CNP was found in all cardiac chambers of controls and its content was ten fold higher in atria than in ventricles (RA: 13.7?1.9 pg/mg; LA: 8.7?3.8 pg/mg; RV: 1.07?0.33 pg/mg; LV: 0.93?0.17 pg/mg). At 4 weeks of pacing stress, myocardial levels of CNP in LV were higher than in controls (15.8?9.9 pg/mg vs.0.9?0.17 pg/mg, p=0.01). The expression of mRNA coding for CNP was higher at 4 weeks of pacing althought CNP gene expression appears to be noticeable lower than that of BNP. The NPR-B resulted to be expressed in all cardiac regions analyzed, and a down-regulation was observed in ventricles after HF. Althought further investigations are necessary, the high tissue levels of CNP found after pacing stress as well as the myocardial CNP and NPR-B expression suggest an important role of this peptide in a so complex pathology as HF

Evaluation of the expression of transcripts coding for CNP and for its specific receptor, NPR-B, by Real Time PCR in cardiac tissue of normal and heart failure animals

Purpose: Higher plasma levels and a cardiac production of C-type natriuretic peptide (CNP) were recently observed in patients with chronic heart failure (HF), but its cellular source and possible difference between atrium and ventricle expression are so far lacking. Aim of this study was to evaluate the expression of transcripts coding for CNP and for its specific receptor, NPR-B, in cardiac tissue (right and left atrium and ventricle) of normal and CHF animals. CNP tissue levels were also determined in cardiac extracts. Methods: Adult male minipigs (n=5) were chronically instrumented with a unipolar pacemaker connected to the anterior left ventricular (LV) wall. HF was induced by rapid pacing (180 beats/min) for 4 weeks. End-stage HF occurred at 24?2 days of pacing when the LV end-diastolic pressure was !25 mmHg. As control, we studied 5 adult male minipigs. At 4 weeks, myocardial samples were collected. Both CNP mRNA and proteins were extracted from a same sample with the method of phenol/guanidine-thiocyanate/chloroform. Tissue CNP levels were determined by a radioimmunoassay after a preliminary extraction on Sep-Pak C18, while the expression of mRNA coding for CNP and NPR-B in myocardial tissue (n=40) by Real Time reverse transcriptase-polymerase chain reaction (PCR) with DDCt method. As overall control, a parallel Real Time-PCR assay for BNP mRNA expression was carried out in the same samples. Real Time-PCR analysis was performed using an automated sequence instrument (7900HT Fast, Applied Biosystems) for the real-time monitoring of nucleic acid green dye fluorescence (SYBR Green I). Results: As to myocardial extracts, CNP was found in all cardiac chambers of controls and its content was ten fold higher in atria than in ventricles (RA: 13.7?1.9 pg/mg; LA: 8.7?3.8 pg/mg; RV: 1.07?0.33 pg/mg; LV: 0.93?0.17 pg/mg). At 4 weeks of pacing stress, myocardial levels of CNP in LV were higher than in controls (15.8?9.9 pg/mg vs.0.9?0.17 pg/mg, p=0.01). The expression of mRNA coding for CNP was higher at 4 weeks of pacing althought CNP gene expression appears to be noticeable lower than that of BNP. The NPR-B resulted to be expressed in all cardiac regions analyzed, and a down-regulation was observed in ventricles after HF. Althought further investigations are necessary, the high tissue levels of CNP found after pacing stress as well as the myocardial CNP and NPR-B expression suggest an important role of this peptide in a so complex pathology as HF

Site-specific integration in mammalian cells mediated by a new hybrid baculovirus-adeno-associated virus vector

Baculovirus can transiently transduce primary human and rat hepatocytes, as well as a subset of stable celllines. To prolong transgene expression, we have developed new hybrid vectors which associate key elementsfrom adeno-associated virus (AAV) with the elevated transducing capacity of baculovirus. The hybrid vectorscontain a transgene cassette composed of the !-galactosidase (!-Gal) reporter gene and the hygromycin resistance(Hygr) gene flanked by the AAV inverted terminal repeats (ITRs), which are necessary for AAV replicationand integration in the host genome. Constructs were derived both with and without the AAV rep geneunder the p5 and p19 promoters cloned in different positions with respect to the baculovirus polyheidrinpromoter. A high-titer preparation of baculovirus-AAV (Bac-AAV) chimeric virus containing the ITR–Hygr–!-Gal sequence was obtained with insect cells only when the rep gene was placed in an antisense orientationto the polyheidrin promoter. Infection of 293 cells with Bac-AAV virus expressing the rep gene results in a 10-to 50-fold increase in the number of Hygr stable cell clones. Additionally, rep expression determined the localizationof the transgene cassette in the aavs1 site in approximately 41% of cases as detected by bothSouthern blotting and fluorescent in situ hybridization analysis. Moreover, site-specific integration of the ITRflankedDNA was also detected by PCR amplification of the ITR-aavs1 junction in transduced human fibroblasts.These data indicate that Bac-AAV hybrid vectors can allow permanent, nontoxic gene delivery of DNAconstructs for ex vivo treatment of primary human cells

Real time PCR evaluation for c-type natriuretic peptide and for its specific receptor, NPR-B in cardiac tissue of normal and chronic heart failure animals

Background. C-type natriuretic peptide (CNP) was recently found in the myocardium, but possible differences between atrium and ventricle production are so far lacking. Aim. To evaluate the expression of transcripts coding for CNP and for its specific receptor, NPR-B, in cardiac tissue (right and left atrium and ventricle) of normal and HF animals. Methods. Cardiac tissue was collected from male adult minipigs without (control, n=5) and with pacing-induced HF (n=5). HF was induced by rapid pacing (180 beats/ min) for 3 weeks. mRNA was extracted with the method of phenol/guanidine-thiocyanate/chloroform. The expression of mRNA coding for CNP and NPR-B was determined in myocardial tissue (n=40) by Real Time-PCR with DDCt method. As overall control, a parallel Real Time-PCR assay for BNP mRNA expression was carried out in the same samples. Results. CNP gene expression was observed in controls and at 3 weeks of pacing resulting lower than that of BNP (left ventricle: p=0.05 controls vs. HF). As expected, BNP gene expression in all the cardiac chambers resulted higher after 3 weeks of pacing compared to normal heart (right atrium and left ventricle: p=0.003 controls vs. HF). Moreover, BNP mRNA expression was higher in atrium than in ventricle. We also observed higher, but not significantly, levels of CNP mRNA expression between normal and HF animals in all chambers. The NPR-B resulted to be expressed in all cardiac regions analyzed, and a down- regulation was observed in ventricles after HF (right ventricle p=0.001 controls vs. HF). Conclusions. In the present study, we provided the first evidence of CNP and NPR-B expression in tissue from normal and HF. The increased myocardial CNP synthesis was associated to the NPR-B down regulation in HF. The co-localization of the CNP system and its specific receptor suggests a possible role of this peptide in a complex pathology such as HF and the present results may prompt novel therapeutical strategies targeting NPR-B

Mismatch between mRNA cardiac expression of BNP and CNP in pacing-induced heart failure

Purpose: It has been recently demonstrated in an animal model of heart failure (HF) that the high-frequency pacing of the left ventricle (LV) free wall causes a dyssynchronous pattern of contraction that leads to progressive cardiac failure with pronounced differences in regional contractility. Aim of this study was to evaluate the possible variation of brain natriuretic peptide (BNP) and C-type natriuretic peptide (CNP) mRNA expression in the anterior/anterior lateral region (pacing site, PS) compared with the infero-septal region (opposite site, OS) to individualize the possible association between the contraction patterns and the expression of these biomarkers. Methods: Cardiac tissue was collected from male adult minipigs without (controls, n=6) and with pacing-induced HF (n=8) from PS, and from the tissue remote from the pacing-site. mRNA expression of BNP and CNP was evaluated by semiquantitative polymerase chain reaction (PCR) by using GAPDH as housing gene. Results: A significant difference in mRNA expression of BNP in PS was observed between HF animals and controls (BNP/GAPDH: 0.65?0.11 vs. 0.35?0.04, p=0.02) whereas in OS BNP levels resulted similar to those of controls (BNP/GAPDH: 0.36?0.05). mRNA expression of CNP was higher in HF with respect to controls both in PS and in OS, although not significantly (CNP/GAPDH: controls 0.089?0.036, PS 0.29?0.23, OS 0.54?0.16). These findings are in tune with the increase of CNP tissue concentrations (controls=0.69?0.13; PS=1.56?0.19; OS=1.70?0.42 pg/mg protein; p=0.039 controls vs.OS). The higher levels of BNP mRNA expression in PS are in agreement with a reduction of contractile function in this region while the higher CNP mRNA expression in OS could suggest the presence of a major endothelial dysfunction in the remote region. Conclusions: In clinical conditions the endothelial dysfunction precedes the overt HF, so, although further investigations are necessary, these results suggest that CNP could be a early marker of HF. In this context, CNP could be a marker more relevant than BNP in early recognizing patients with HF

Geosynchronous SAR for Terrain & atmosphere with short revisit (GeoSTARe)

Geo STA Re would be a mission combining the continuous view capabilities from geostationary orbits of super-continental areas with the all-day, all-weather imaging capabilities of Synthetic Aperture Radar. It would complement Copernicus Sentinel-1 bringing the repeat time from days down to hours. In that, it would provide novel and unique observations. The well proven potentials of Radar in sensing roughness, deformations, and moisture, combined with the short time to get any image, from minutes to an hour, and the immediate data download and exploitation (thanks to the geostationary orbit) makes GeoSTARe a game changer in those fields where hourly-to-daily monitoring is a must

N-Acetylaspartate Drives Oligodendroglial Differentiation via Histone Deacetylase Activation

An unmet clinical goal in demyelinating pathologies is to restore the myelin sheath prior to neural degeneration. N-acetylaspartate (NAA) is an acetylated derivative form of aspartate, abundant in the healthy brain but severely reduced during traumatic brain injury and in patients with neurodegenerative pathologies. How extracellular NAA variations impact the remyelination process and, thereby, the ability of oligodendrocytes to remyelinate axons remains unexplored. Here, we evaluated the remyelination properties of the oligodendroglial (OL) mouse cell line Oli-neuM under different concentrations of NAA using a combination of biochemical, qPCR, immunofluorescence assays, and in vitro engagement tests, at NAA doses compatible with those observed in healthy brains and during brain injury. We observed that oligodendroglia cells respond to decreasing levels of NAA by stimulating differentiation and promoting gene expression of myelin proteins in a temporally regulated manner. Low doses of NAA potently stimulate Oli-neuM to engage with synthetic axons. Furthermore, we show a concentration-dependent expression of specific histone deacetylases essential for MBP gene expression under NAA or Clobetasol treatment. These data are consistent with the idea that oligodendrocytes respond to lowering the NAA concentration by activating the remyelination process via deacetylase activation