Endothelial NOS (NOS3) impairs myocardial function in developing sepsis

Endothelial nitric oxide synthase (NOS)3-derived nitric oxide (NO) modulates inotropic response and diastolic interval for optimal cardiac performance under non-inflammatory conditions. In sepsis, excessive NO production plays a key role in severe hypotension and myocardial dysfunction. We aimed to determine the role of NOS3 on myocardial performance, NO production, and time course of sepsis development. NOS3(−/−) and C57BL/6 wildtype mice were rendered septic by cecum ligation and puncture (CLP). Cardiac function was analyzed by serial echocardiography, in vivo pressure and isolated heart measurements. Cardiac output (CO) increased to 160 % of baseline at 10 h after sepsis induction followed by a decline to 63 % of baseline after 18 h in wildtype mice. CO was unaltered in septic NOS3(−/−) mice. Despite the hyperdynamic state, cardiac function and mean arterial pressure were impaired in septic wildtype as early as 6 h post CLP. At 12 h, cardiac function in septic wildtype was refractory to catecholamines in vivo and respective isolated hearts showed impaired pressure development and limited coronary flow reserve. Hemodynamics remained stable in NOS3(−/−) mice leading to significant survival benefit. Unselective NOS inhibition in septic NOS3(−/−) mice diminished this survival benefit. Plasma NO(x)- and local myocardial NO(x)- and NO levels (via NO spin trapping) demonstrated enhanced NO(x)- and bioactive NO levels in septic wildtype as compared to NOS3(−/−) mice. Significant contribution by inducible NOS (NOS2) during this early phase of sepsis was excluded. Our data suggest that NOS3 relevantly contributes to bioactive NO pool in developing sepsis resulting in impaired cardiac contractility. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s00395-013-0330-8) contains supplementary material, which is available to authorized users

Desmoglein 2 mutant mice develop cardiac fibrosis and dilation

Desmosomes are cell–cell adhesion sites and part of the intercalated discs, which couple adjacent cardiomyocytes. The connection is formed by the extracellular domains of desmosomal cadherins that are also linked to the cytoskeleton on the cytoplasmic side. To examine the contribution of the desmosomal cadherin desmoglein 2 to cardiomyocyte adhesion and cardiac function, mutant mice were prepared lacking a part of the extracellular adhesive domain of desmoglein 2. Most live born mutant mice presented normal overall cardiac morphology at 2 weeks. Some animals, however, displayed extensive fibrotic lesions. Later on, mutants developed ventricular dilation leading to cardiac insufficiency and eventually premature death. Upon histological examination, cardiomyocyte death by calcifying necrosis and replacement by fibrous tissue were observed. Fibrotic lesions were highly proliferative in 2-week-old mutants, whereas the fibrotic lesions of older mutants showed little proliferation indicating the completion of local muscle replacement by scar tissue. Disease progression correlated with increased mRNA expression of c-myc, ANF, BNF, CTGF and GDF15, which are markers for cardiac stress, remodeling and heart failure. Taken together, the desmoglein 2-mutant mice display features of dilative cardiomyopathy and arrhythmogenic right ventricular cardiomyopathy, an inherited human heart disease with pronounced fibrosis and ventricular arrhythmias that has been linked to mutations in desmosomal proteins including desmoglein 2

Performance of non-invasive tests and histology for the prediction of clinical outcomes in patients with non-alcoholic fatty liver disease: an individual participant data meta-analysis

BackgroundHistologically assessed liver fibrosis stage has prognostic significance in patients with non-alcoholic fatty liver disease (NAFLD) and is accepted as a surrogate endpoint in clinical trials for non-cirrhotic NAFLD. Our aim was to compare the prognostic performance of non-invasive tests with liver histology in patients with NAFLD.MethodsThis was an individual participant data meta-analysis of the prognostic performance of histologically assessed fibrosis stage (F0–4), liver stiffness measured by vibration-controlled transient elastography (LSM-VCTE), fibrosis-4 index (FIB-4), and NAFLD fibrosis score (NFS) in patients with NAFLD. The literature was searched for a previously published systematic review on the diagnostic accuracy of imaging and simple non-invasive tests and updated to Jan 12, 2022 for this study. Studies were identified through PubMed/MEDLINE, EMBASE, and CENTRAL, and authors were contacted for individual participant data, including outcome data, with a minimum of 12 months of follow-up. The primary outcome was a composite endpoint of all-cause mortality, hepatocellular carcinoma, liver transplantation, or cirrhosis complications (ie, ascites, variceal bleeding, hepatic encephalopathy, or progression to a MELD score ≥15). We calculated aggregated survival curves for trichotomised groups and compared them using stratified log-rank tests (histology: F0–2 vs F3 vs F4; LSM: 2·67; NFS: 0·676), calculated areas under the time-dependent receiver operating characteristic curves (tAUC), and performed Cox proportional-hazards regression to adjust for confounding. This study was registered with PROSPERO, CRD42022312226.FindingsOf 65 eligible studies, we included data on 2518 patients with biopsy-proven NAFLD from 25 studies (1126 [44·7%] were female, median age was 54 years [IQR 44–63), and 1161 [46·1%] had type 2 diabetes). After a median follow-up of 57 months [IQR 33–91], the composite endpoint was observed in 145 (5·8%) patients. Stratified log-rank tests showed significant differences between the trichotomised patient groups (p<0·0001 for all comparisons). The tAUC at 5 years were 0·72 (95% CI 0·62–0·81) for histology, 0·76 (0·70–0·83) for LSM-VCTE, 0·74 (0·64–0·82) for FIB-4, and 0·70 (0·63–0·80) for NFS. All index tests were significant predictors of the primary outcome after adjustment for confounders in the Cox regression.InterpretationSimple non-invasive tests performed as well as histologically assessed fibrosis in predicting clinical outcomes in patients with NAFLD and could be considered as alternatives to liver biopsy in some cases

Einfluss des HMG-CoA-Reduktase-Inhibitors Simvastatin auf Überleben und hämodynamische Parameter im murinen Sepsismodell

Sepsis remains one of the leading causes of death among patients treated in intensive care units. Despite significant advances in the understanding of the pathophysiology of sepsis with activation of multiple cellular and humoral pathways in the meantime, treating sepsis is still challenging. Recently, activated protein C and low-dose hydrocortisone demonstrated a reduction of mortality rate. However, the latter remains on a high level ranging between 30% and 50%. Clinical trials and studies in animal models demonstrated so-called pleiotropic effects for HMG-CoA reductase inhibitors beyond their lipid-lowering effects. These pleiotropic effects include anti-inflammatory, immunmodulatory, anticoagulative, antioxidative and antiapoptotic properties and furthermore improvement of endothelial function, which could affect the complex interactions of the pathophysiology of sepsis. The present study investigates whether treatment with the HMG-CoA reductase inhibitor simvastatin might improve survival and cardiovascular function in a murine model of sepsis. After intraperitoneal injection of simvastatin, sepsis was induced via cecum ligation and puncture (CLP). This polymicrobial model of sepsis closely resembles the hemodynamic and metabolic phases of human sepsis. We observed typical sepsis criteria in our model including bacteremia. To address possible changes in cardiovascular function we obtained cardiovascular parameters by echocardiography and intraarteriell blood pressure measurements. In addition we performed studies in an isolated heart Langendorff setup. Inducing sepsis via CLP resulted in 100% lethality in untreated animals. Median survival time was extended from 28 hours in untreated to 108 hours in simvastatin treated mice. Performing echocardiography we observed a hypodynamic state in untreated animals, which developed after a hyperdynamic state analog to human sepsis. In contrast to simvastatin treated animals, untreated mice exhibited a reduced peripheral vascular resistance in the intraarteriell blood pressure measurements. The application of ETU, an unspecific inhibitor of NO synthases, led to an increase of the mean arterial blood pressure in all animal groups indicating a high-level NO production causing vasodilatation and hypotension in sepsis. In untreated mice no significant changes in mean arterial blood pressure and cardiac output were detected after dobutamine stimulation indicating the well described hyporeactivity to catecholamines that occurs in sepsis. Regarding an acute septic cardiomyopathy a significant cardiac dysfunction was documented accompanied by reduction of left ventricular contractility of the isolated heart in the Langendorff setup. In simvastatin treated animals we observed that the responsiveness to the catecholamine dobutamine was restored. In this animal group we detected neither cardiac depression nor significant hypotension in comparison to sham-operated animals. As underlying mechanism for hemodynamic stabilization NO- modulating properties of simvastatin could play a crucial role. Application of the eNOS stimulator bradykinin potentized the already increased NO release by enhancing the eNOS activitiy in untreated septic mice. Consistently, the coronary flow reserve was exhausted in this group of animals. Treatment with simvastatin was followed by conservation of the coronary flow reserve indicating an eNOS-modulating effect of simvastatin. Besides modulating eNOS, iNOS modulation has been described in the literature. Furthermore statins influence leukocyte- endothelial interactions. In addition to anti-inflammatory and immunmodulatory effects of statins anticoagulative, antioxidative and antiapoptotic properties influence different components of the complex pathophysiology of sepsis. The present study demonstrates a hemodynamic stabilization and preserved cardiac function after application of simvastatin leading to a significantly improved survival time in a murine model of sepsis. Better understanding of the pleiotropic effects of statins in addition to retrospective clinical trials and prospective observational studies suggest that statins could possibly play a role in the prevention and therapy of sepsis in the future. Large placebo-controlled blinded randomised trials in patients are clearly needed to assess the value of statins as a new therapeutic approach for sepsis

Einfluss des HMG-CoA-Reduktase-Inhibitors Simvastatin auf Überleben und hämodynamische Parameter im murinen Sepsismodell

Sepsis remains one of the leading causes of death among patients treated in intensive care units. Despite significant advances in the understanding of the pathophysiology of sepsis with activation of multiple cellular and humoral pathways in the meantime, treating sepsis is still challenging. Recently, activated protein C and low-dose hydrocortisone demonstrated a reduction of mortality rate. However, the latter remains on a high level ranging between 30% and 50%. Clinical trials and studies in animal models demonstrated so-called pleiotropic effects for HMG-CoA reductase inhibitors beyond their lipid-lowering effects. These pleiotropic effects include anti-inflammatory, immunmodulatory, anticoagulative, antioxidative and antiapoptotic properties and furthermore improvement of endothelial function, which could affect the complex interactions of the pathophysiology of sepsis. The present study investigates whether treatment with the HMG-CoA reductase inhibitor simvastatin might improve survival and cardiovascular function in a murine model of sepsis. After intraperitoneal injection of simvastatin, sepsis was induced via cecum ligation and puncture (CLP). This polymicrobial model of sepsis closely resembles the hemodynamic and metabolic phases of human sepsis. We observed typical sepsis criteria in our model including bacteremia. To address possible changes in cardiovascular function we obtained cardiovascular parameters by echocardiography and intraarteriell blood pressure measurements. In addition we performed studies in an isolated heart Langendorff setup. Inducing sepsis via CLP resulted in 100% lethality in untreated animals. Median survival time was extended from 28 hours in untreated to 108 hours in simvastatin treated mice. Performing echocardiography we observed a hypodynamic state in untreated animals, which developed after a hyperdynamic state analog to human sepsis. In contrast to simvastatin treated animals, untreated mice exhibited a reduced peripheral vascular resistance in the intraarteriell blood pressure measurements. The application of ETU, an unspecific inhibitor of NO synthases, led to an increase of the mean arterial blood pressure in all animal groups indicating a high-level NO production causing vasodilatation and hypotension in sepsis. In untreated mice no significant changes in mean arterial blood pressure and cardiac output were detected after dobutamine stimulation indicating the well described hyporeactivity to catecholamines that occurs in sepsis. Regarding an acute septic cardiomyopathy a significant cardiac dysfunction was documented accompanied by reduction of left ventricular contractility of the isolated heart in the Langendorff setup. In simvastatin treated animals we observed that the responsiveness to the catecholamine dobutamine was restored. In this animal group we detected neither cardiac depression nor significant hypotension in comparison to sham-operated animals. As underlying mechanism for hemodynamic stabilization NO- modulating properties of simvastatin could play a crucial role. Application of the eNOS stimulator bradykinin potentized the already increased NO release by enhancing the eNOS activitiy in untreated septic mice. Consistently, the coronary flow reserve was exhausted in this group of animals. Treatment with simvastatin was followed by conservation of the coronary flow reserve indicating an eNOS-modulating effect of simvastatin. Besides modulating eNOS, iNOS modulation has been described in the literature. Furthermore statins influence leukocyte- endothelial interactions. In addition to anti-inflammatory and immunmodulatory effects of statins anticoagulative, antioxidative and antiapoptotic properties influence different components of the complex pathophysiology of sepsis. The present study demonstrates a hemodynamic stabilization and preserved cardiac function after application of simvastatin leading to a significantly improved survival time in a murine model of sepsis. Better understanding of the pleiotropic effects of statins in addition to retrospective clinical trials and prospective observational studies suggest that statins could possibly play a role in the prevention and therapy of sepsis in the future. Large placebo-controlled blinded randomised trials in patients are clearly needed to assess the value of statins as a new therapeutic approach for sepsis

Forests and Their Hydrological Effects in Mediterranean Mountains - The Case of the Central Spanish Pyrenees

7 páginas, 6 figuras.-- Este artículo se encuentra bajo Licencia Creative Commons.This article considers the effects of forests on the hydrology of a Mediterranean mountain area. Variations of climate factors, discharge, interception, and water table depth in the San Salvador forested experimental catchment in the Central Spanish Pyrenees were studied and the results compared with those from two deforested catchments. The hydrological response of the San Salvador catchment had the following properties: 1) it had both smaller peak flows and smaller low flows than the deforested catchments; 2) most rainstorm events produced almost no discharge response; 3) the intensity of precipitation had no influence on the magnitude of peak flows; and 4) depth to the water table was the most important factor in the relationship between precipitation and discharge. These results confirm that forest conservation reduces floods and soil erosion, particularly on steep slopes.Peer reviewe

Circulating NOS3 Modulates Left Ventricular Remodeling following Reperfused Myocardial Infarction

<div><p>Purpose</p><p>Nitric oxide (NO) is constitutively produced and released from the endothelium and several blood cell types by the isoform 3 of the NO synthase (NOS3). We have shown that NO protects against myocardial ischemia/reperfusion (I/R) injury and that depletion of circulating NOS3 increases within 24h of ischemia/reperfusion the size of myocardial infarction (MI) in chimeric mice devoid of circulating NOS3. In the current study we hypothesized that circulating NOS3 also affects remodeling of the left ventricle following reperfused MI.</p><p>Methods</p><p>To analyze the role of circulating NOS3 we transplanted bone marrow of NOS3^−/− and wild type (WT) mice into WT mice, producing chimerae expressing NOS3 only in vascular endothelium (BC−/EC+) or in both, blood cells and vascular endothelium (BC+/EC+). Both groups underwent 60 min of coronary occlusion in a closed-chest model of reperfused MI. During the 3 weeks post MI, structural and functional LV remodeling was serially assessed (24h, 4d, 1w, 2w and 3w) by echocardiography. At 72 hours post MI, gene expression of several extracellular matrix (ECM) modifying molecules was determined by quantitative RT-PCR analysis. At 3 weeks post MI, hemodynamics were obtained by pressure catheter, scar size and collagen content were quantified post mortem by Gomori’s One-step trichrome staining.</p><p>Results</p><p>Three weeks post MI, LV end-systolic (53.2±5.9μl;***p≤0.001;n = 5) and end-diastolic volumes (82.7±5.6μl;*p<0.05;n = 5) were significantly increased in BC−/EC+, along with decreased LV developed pressure (67.5±1.8mmHg;n = 18;***p≤0.001) and increased scar size/left ventricle (19.5±1.5%;n = 13;**p≤0.01) compared to BC+/EC+ (ESV:35.6±2.2μl; EDV:69.1±2.6μl n = 8; LVDP:83.2±3.2mmHg;n = 24;scar size/LV13.8±0.7%;n = 16). Myocardial scar of BC−/EC+ was characterized by increased total collagen content (20.2±0.8%;n = 13;***p≤0.001) compared to BC+/EC+ (15.9±0.5;n = 16), and increased collagen type I and III subtypes.</p><p>Conclusion</p><p>Circulating NOS3 ameliorates maladaptive left ventricular remodeling following reperfused myocardial infarction.</p></div