Nitric oxide inactivates rat hepatic methionine adenosyltransferase In vivo by S-nitrosylation

We investigated the mechanism of nitric oxide (NO) action on hepatic methionine adenosyltransferase (MAT) activity using S-nitrosoglutathione (GSNO) as NO donor. Hepatic MAT plays an essential role in the metabolism of methionine, converting this amino acid into S-adenosylmethionine. Hepatic MAT exists in two oligomeric states: as a tetramer (MAT I) and as a dimer (MAT III) of the same subunit. This subunit contains 10 cysteine residues. In MAT I, S-nitrosylation of 1 thiol residue per subunit was associated with a marked inactivation of the enzyme (about 70%) that was reversed by glutathione (GSH). In MAT III, S-nitrosylation of 3 thiol residues per subunit led to a similar inactivation of the enzyme, which was also reversed by GSH. Incubation of isolated rat hepatocytes with S-nitrosoglutathione monoethyl ester (EGSNO), a NO donor permeable through the cellular membrane, induced a dose-dependent inactivation of MAT that was reversed by removing the NO donor from the cell suspension. MAT, purified from isolated rat hepatocytes, contained S-nitrosothiol groups and the addition of increasing concentrations of EGSNO to the hepatocyte suspension led to a progressive S-nitrosylation of the enzyme. Removal of the NO donor from the incubation media resulted in loss of most NO groups associated to the enzyme. Finally, induction in rats of the production of NO, by the administration of bacterial lipopolysaccharide (LPS), induced a fivefold increase in the S-nitrosylation of hepatic MAT, which led to a marked inactivation of the enzyme. Thus, the activity of liver MAT appears to be regulated in vivo by S-nitrosylation

Acidified milk for feeding dairy calves in tropical raising systems

The objective of this study was to evaluate the effect of milk acidification in tropical climate conditions on dairy calves’ growth, health and selected blood metabolites. Thirty-two Holstein calves were blocked according to sex, birth date and weight, and distributed to the following treatments: 1. refrigerated milk kept at 5 °C (RM) or 2. acidified milk (with added lactic acid to a pH of 4.2) kept at ambient temperature (ACM). After birth, calves were fed colostrum and from the second day received 6 l/day of RM or ACM heated to 38 °C until weaning at day 56. Calves were individually housed with free access to water and starter diet. Feed intake and health problems were monitored daily; calves were weighed and measured weekly. Blood samples were collected weekly to evaluate the levels of metabolites. Feed intake, body weight and daily gain did not differ between treatments, but heart girth and wither height was higher for animals fed RM. The faecal score was lower for RM group, however in calves fed ACM it also did not suggest a diarrheal process (1.98). In addition, the first case of diarrhoea in calves fed ACM was later than in calves fed RM (15.4 vs 8.6 days, respectively; P < 0.01). So, the acidification of milk is an adequate method of preserving milk in tropical ambient temperatures. It resulted in health benefits to calves, delaying the first case of diarrhoea.Fil: Coelho, M. G.. Universidade do Sao Paulo. Escola Superior de Agricultura Luiz de Queiroz; BrasilFil: Silva, F. L. M.. Universidade do Sao Paulo. Escola Superior de Agricultura Luiz de Queiroz; BrasilFil: Silva, M. D.. Universidade do Sao Paulo. Escola Superior de Agricultura Luiz de Queiroz; BrasilFil: Silva, A. P.. Universidade do Sao Paulo. Escola Superior de Agricultura Luiz de Queiroz; BrasilFil: Cezar, A. M.. Universidade do Sao Paulo. Escola Superior de Agricultura Luiz de Queiroz; BrasilFil: Slanzon, G. S.. Universidade do Sao Paulo. Escola Superior de Agricultura Luiz de Queiroz; BrasilFil: Miqueo, Evangelina. Universidade do Sao Paulo. Escola Superior de Agricultura Luiz de Queiroz; Brasil. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Toledo, A. F.. Universidade do Sao Paulo. Escola Superior de Agricultura Luiz de Queiroz; BrasilFil: Bittar, C. M. M.. Universidade do Sao Paulo. Escola Superior de Agricultura Luiz de Queiroz; Brasi

Spatial distribution of PAH concentrations and stable isotope signatures (δ13C, δ15N) in mosses from three European areas – Characterization by multivariate analysis

Polycyclic aromatic hydrocarbon (PAH) concentrations and N, C stable isotope signatures were determined in mosses Hypnum cupressiforme Hedw. from 61 sites of 3 European regions: Île-de-France (France); Navarra (Spain); the Swiss Plateau and Basel area (Switzerland). Total PAH concentrations of 100-700 ng g-1, as well as δ13C values of -32 to -29‰ and δ15N values of -11 to -3‰ were measured. Pearson correlation tests revealed opposite trends between high molecular weight PAH (4-6 aromatic rings) content and δ13C values. Partial Least Square regressions explained the very significant correlations (r > 0.91, p < 0.001) between high molecular weight PAH concentrations by local urban land use (<10 km) and environmental factors such as elevation and pluviometry. Finally, specific correlations between heavy metal and PAH concentrations were attributed to industrial emissions in Switzerland and road traffic emissions in Spain

Cartilage intermediate layer protein 1 (CILP1): a novel mediator of cardiac extracellular matrix remodelling

Heart failure is accompanied by extracellular matrix (ECM) remodelling, often leading to cardiac fibrosis. In the present study we explored the significance of cartilage intermediate layer protein 1 (CILP1) as a novel mediator of cardiac ECM remodelling. Whole genome transcriptional analysis of human cardiac tissue samples revealed a strong association of CILP1 with many structural (e.g. COL1A2 r2¿=¿0.83) and non-structural (e.g. TGFB3 r2¿=¿0.75) ECM proteins. Gene enrichment analysis further underscored the involvement of CILP1 in human cardiac ECM remodelling and TGFß signalling. Myocardial CILP1 protein levels were significantly elevated in human infarct tissue and in aortic valve stenosis patients. CILP1 mRNA levels markedly increased in mouse heart after myocardial infarction, transverse aortic constriction, and angiotensin II treatment. Cardiac fibroblasts were found to be the primary source of cardiac CILP1 expression. Recombinant CILP1 inhibited TGFß-induced ¿SMA gene and protein expression in cardiac fibroblasts. In addition, CILP1 overexpression in HEK293 cells strongly (5-fold p¿<¿0.05) inhibited TGFß signalling activity. In conclusion, our study identifies CILP1 as a new cardiac matricellular protein interfering with pro-fibrotic TGFß signalling, and as a novel sensitive marker for cardiac fibrosis

The combination of carboxy-terminal propeptide of procollagen type I blood levels and late gadolinium enhancement at cardiac magnetic resonance provides additional prognostic information in idiopathic dilated cardiomyopathy - A multilevel assessment of myocardial fibrosis in dilated cardiomyopathy

Aims To determine the prognostic value of multilevel assessment of fibrosis in dilated cardiomyopathy (DCM) patients. Methods and results We quantified fibrosis in 209 DCM patients at three levels: (i) non-invasive late gadolinium enhancement (LGE) at cardiac magnetic resonance (CMR); (ii) blood biomarkers [amino-terminal propeptide of procollagen type III (PIIINP) and carboxy-terminal propeptide of procollagen type I (PICP)], (iii) invasive endomyocardial biopsy (EMB) (collagen volume fraction, CVF). Both LGE and elevated blood PICP levels, but neither PIIINP nor CVF predicted a worse outcome defined as death, heart transplantation, heart failure hospitalization, or life-threatening arrhythmias, after adjusting for known clinical predictors [adjusted hazard ratios: LGE 3.54, 95% confidence interval (CI) 1.90-6.60; P < 0.001 and PICP 1.02, 95% CI 1.01-1.03; P = 0.001]. The combination of LGE and PICP provided the highest prognostic benefit in prediction (likelihood ratio test P = 0.007) and reclassification (net reclassification index: 0.28, P = 0.02; and integrated discrimination improvement index: 0.139, P = 0.01) when added to the clinical prediction model. Moreover, patients with a combination of LGE and elevated PICP (LGE+/PICP+) had the worst prognosis (log-rank P < 0.001). RNA-sequencing and gene enrichment analysis of EMB showed an increased expression of pro-fibrotic and pro-inflammatory pathways in patients with high levels of fibrosis (LGE+/PICP+) compared to patients with low levels of fibrosis (LGE-/PICP-). This would suggest the validity of myocardial fibrosis detection by LGE and PICP, as the subsequent generated fibrotic risk profiles are associated with distinct cardiac transcriptomic profiles. Conclusion The combination of myocardial fibrosis at CMR and circulating PICP levels provides additive prognostic value accompanied by a pro-fibrotic and pro-inflammatory transcriptomic profile in DCM patients with LGE and elevated PICP

The role of titin and extracellular matrix remodelling in heart failure with preserved ejection fraction

Heart failure with preserved ejection fraction (HFpEF) is characterised by a high incidence of metabolic comorbidities that share the potential to induce both systemic and coronary microvascular inflammation and oxidative stress. These pathophysiological alterations contribute to increased passive stiffness of the myocardium and to diastolic dysfunction, both hallmarks of HFpEF. Passive myocardial stiffness depends mainly on two components: the extracellular matrix (ECM) and the cardiomyocytes. Quantitative and qualitative changes in collagen metabolism leading to myocardial fibrosis determine the ECM-based stiffness of the myocardium. Different noninvasive diagnostic tools to assess myocardial fibrosis are being developed, some of which have demonstrated to correlate with clinical status and prognosis. Cardiomyocytes mainly alter the passive stiffness through alterations in the giant myofilament titin, which serves as a spring. By modifying its phosphorylation state or by direct oxidative effects, titin determines cardiomyocyte-based passive stiffness. Probably the relative importance of cardiomyocyte-based changes is more important in the beginning of the disease, whereas ECM-based changes become more prominent in the more advanced stages. The present review focuses on these changes in ECM and cardiomyocytes in HFpEF and their potential prognostic and therapeutic implications

Remodelado miocárdico en la insuficiencia cardiaca con fracción de eyección preservada en la rata Dahl/SS

El miocardio de las ratas Dahl/SS con ICFEP presenta las alteraciones propias del remodelado miocárdico en la ICFEP: fibrosis miocárdica, hipertrofia de los CMs y rarefacción de los capilares intramiocárdicos. Estos aspectos se asocian con el desarrollo de HVI y DD, haciendo de este modelo una herramienta adecuada para estudiar la ICFEP humana. La fibrosis miocárdica de las ratas Dahl/SS con ICFEP se caracteriza por un aumento del depósito de las fibras de colágeno tanto en la zona perivascular como en el espacio intersticial. Este incremento no se limita al VI sino que afecta también al VD y al SI