3',4'-Dihydroxyflavonol antioxidant attenuates aiastolic dysfunction and cardiac remodeling in streptozotocin-induced diabetic m(Ren2)27 rats

Background Diabetic cardiomyopathy (DCM) is an increasingly recognized cause of chronic heart failure amongst diabetic patients. Both increased reactive oxygen species (ROS) generation and impaired ROS scavenging have been implicated in the pathogenesis of hyperglycemia-induced left ventricular dysfunction, cardiac fibrosis, apoptosis and hypertrophy. We hypothesized that 3',4'-dihydroxyflavonol (DiOHF), a small highly lipid soluble synthetic flavonol, may prevent DCM by scavenging ROS, thus preventing ROS-induced cardiac damage. Methodology/Principal Findings Six week old homozygous Ren-2 rats were randomized to receive either streptozotocin or citrate buffer, then further randomized to receive either DiOHF (1 mg/kg/day) by oral gavage or vehicle for six weeks. Cardiac function was assessed via echocardiography and left ventricular cardiac catheterization before the animals were sacrificed and hearts removed for histological and molecular analyses. Diabetic Ren-2 rats showed evidence of diastolic dysfunction with prolonged deceleration time, reduced E/A ratio, and increased slope of end-diastolic pressure volume relationship (EDPVR) in association with marked interstitial fibrosis and oxidative stress (all P<0.05 vs control Ren-2). Treatment with DiOHF prevented the development of diastolic dysfunction and was associated with reduced oxidative stress and interstitial fibrosis (all P<0.05 vs untreated diabetic Ren-2 rats). In contrast, few changes were seen in non-diabetic treated animals compared to untreated counterparts. Conclusions Inhibition of ROS production and action by DiOHF improved diastolic function and reduced myocyte hypertrophy as well as collagen deposition. These findings suggest the potential clinical utility of antioxidative compounds such as flavonols in the prevention of diabetes-associated cardiac dysfunction

Die Surfactantkonversion als enzymatischer Prozeß : Ist das Surfactantprotein SP-B ein Substrat der Konvertase?

Das in der Alveole der Säugerlungen vorkommende Surfactantmaterial kann in sogenannte small und large surfactant aggregates aufgetrennt werden. Zu den large surfactant aggregates zählen Lamellarkörperchen und tubuläres Myelin, also die biophysikalisch hochaktiven Präkursoren des interfacialen Surfactantfilms. Unter den Prämissen einer akuten respiratorischen Insuffizienz ist wiederholt festgestellt worden, dass die Verteilung zwischen den large surfactant aggregates und small surfactant aggregates sehr zugunsten der small surfactant aggregates verschoben ist. Hieraus resultierend findet sich ein Übergewicht dieser, biophysikalisch weitgehend inaktiven, Abbauprodukte des Grenzflächenfilms. Vor diesem Hintergrund wurde in der vorliegenden Doktorarbeit der Fragestellung nachgegangen, wodurch die alveoläre Umwandlung der large in die small surfactant aggregates, ein als Surfactantkonversion bezeichneter Vorgang, vermittelt wird, und ob diese Surfactantkonversion ein enzymatisch getriggerter Prozess ist. Zur Beantwortung dieser Frage wurde als Ausgangsmaterial eine gepoolte bronchoalveoläre Lavage von gesunden Kaninchen, sowie ein rekonstituiertes Surfactantmaterial verwendet. Methodisch kamen weiterhin chromatographische, elektrophoretische, biophysikalische Verfahren, sowie Enzymaktivitäts-Assays zur Anwendung. Zunächst einmal konnte festgestellt werden, dass für die weitreichende Konversion von Surfactant in vitro in der Tat die Gegenwart einer Esterase notwendig ist. Weiterhin ergab sich im Rahmen der Rekonstitutionsversuche mit variablen Surfactant-Apoproteinen ebenfalls der Hinweis, dass vor allen Dingen der relative Gehalt an SP-B einen weitreichenden Einfluss auf den Konversionsgrad ausübt. Bei der Untersuchung der Herkunft der Esteraseaktivität in der BAL zeigte sich, dass im Überstand der resuspendierten Zellen der bronchoalveolären Lavage, wie auch im Zelllysat erhebliche Mengen an Esteraseaktivität nachweisbar waren. Weiterhin wurde festgestellt, dass unter den Bedingungen einer in vitro Konversion die Esteraseaktivität in den Subfraktionen alveolären Surfactans zeitabhängig abfiel. So war in den large surfactant aggregates 42 min nach Beginn der in vitro Konversion überhaupt keine Esteraseaktivität und nur noch etwa ein Viertel der Amidaseaktivität nachweisbar. Auf der Suche nach dem möglichen Substrat dieser Esterase wurde sowohl für die natürliche, wie auch für isoliert mit - an Sepharose gekoppelter - Esterase inkubiertem Surfactantprotein B der Nachweis erbracht, dass im Rahmen des Konversionsprozesses das dimere SP-B abgebaut und ein Spaltprodukt in einem Molekulargewichtsbereich von 11-14 kDa neu auftritt. Eine aminoterminale Sequenzierung dieses Spaltproduktes ergab zweifelsfrei den Nachweis eines Surfactantprotein B entstammenden Proteins und zwar des aminoterminalen Anteils des SP-B. Dieses Spaltprodukt konnte durch ein neu entwickeltes HPLC-Verfahren zur Auftrennung der hydrophoben Surfactantproteine aus der BAL weiter aufgereinigt werden. Zusammenfassend ergibt sich auf der Basis der hier vorliegenden Daten der Befund, dass die Umwandlung von large in small surfactant aggregates und der hiermit verbundene Verlust der Oberflächenaktivität nicht nur von der Größe der Oberflächenveränderung, sondern zudem von der Gegenwart einer enzymatischen Aktivität abhängig sind. Im Rahmen der hier durchgeführten Untersuchung konnte der Nachweis einer Esteraseaktivität sowohl in den Zellen der BAL, wie auch im zellfreien Überstand erbracht werden. Als mögliches Substrat dieser Aktivität konnte das Surfactantprotein B identifiziert werden, für welches das Auftreten eines 11-14 kDa großen Spaltproduktes einwandfrei belegt werden konnte. Aus der Kenntnis dieser Ergebnisse leiten sich mögliche neue Therapieoptionen für das Acute Respiratory Distress Syndrome, wie auch für den Ventilator Induced Lung Injury ab, bei denen Verschiebungen des alveolären Surfactantpools zugunsten der small surfactant aggregates wiederholt beschrieben worden sind.The alveolar surfactant pool can be separated into the \u27large surfactant aggregates\u27 (LSA) and the \u27small surfactant aggregates\u27 (SSA). The LSA, including lamellar bodies and tubular myelin, represent the biophysically highly active precursors of the interfacial surfactant film. Under cyclic area changes LSA are converted into the SSA (surfactant conversion). In contrast to LSA the SSA are clearly less surface active. Under clinical conditions of the acute respiratory distress syndrome, the balance of LSA to SSA is found to be switched in favour of SSA. Under these conditions, the alveolar surfactant pool predominantly consists of the largely inactive small surfactant aggregates, thus favouring impairment of gas exchange and lung function. Drawn against this background we aimed to elucidate the mechanisms of the conversion process. To answer this question pooled bronchoalveolar lavages of healthy rabbits and reconstituted surfactant preparations were subjected to repetitive surface area changes in vitro and extend of conversion was analysed. Besides chromatographic, electrophoretic and biophysical techniques, enzyme activity assays were applied for experimental investigations. It was found that an esterase activity is necessary for the induction of surfactant conversion under cyclic surface area changes. Experiments with various concentrations of the different surfactant proteins SP-A, SP-B or SP-C in reconstituted lipid mixtures revealed that only SP-B has a profound impact on the extent of in vitro conversion. Enzyme activity assays showed high esterase activity in complete cell suspensions of bronchoalveolar lavage and cell lysates. Under conditions of in vitro conversion, the esterase activity was found to decline in dependency of the incubation time, resulting in complete loss of esterase activity after 42 min of in vitro conversion. With emphasis on the potential role of surfactant proteins as substrates of esterase activity, we could show that in vitro conversion of BAL as well as incubation of isolated SP-B with sepharose linked esterase would result in a cleavage of dimeric SP-B and detection of a new protein band with a molecular range of 11-14 kilodalton. Amino terminal sequencing revealed that this protein truly represents a cleavage product of the amino terminal part of SP-B. Further purification of the cleavage product was performed by a new developed HPLC method for separation from other hydrophobic surfactant proteins and phospholipids. In summary the presented data support the conclusion that conversion of large surfactant aggregates to small surfactant aggregates not only depends on cyclic changes of the air-liquid interface, but also on the presence of an esterase activity. This esterase activity was detected in the cytosolic fraction of BAL cells, mostly alveolar macrophages. A SP-B cleavage product with a molecular range of 11-14 kilodalton was identified upon in vitro incubation of esterase with SP-B and after in vitro conversion of a rabbit BAL pool, suggesting that SP-B is a substrate of the alveolar esterase. These data may help to identify new molecular targets to treat acute respiratory distress syndrome and ventilator induced lung injury

Atorvastatin Therapy during the Peri-Infarct Period Attenuates Left Ventricular Dysfunction and Remodeling after Myocardial Infarction

Although statins impart a number of cardiovascular benefits, whether statin therapy during the peri-infarct period improves subsequent myocardial structure and function remains unclear. Thus, we evaluated the effects of atorvastatin on cardiac function, remodeling, fibrosis, and apoptosis after myocardial infarction (MI). Two groups of rats were subjected to permanent coronary occlusion. Group II (n = 14) received oral atorvastatin (10 mg/kg/d) daily for 3 wk before and 4 wk after MI, while group I (n = 12) received equivalent doses of vehicle. Infarct size (Masson's trichrome-stained sections) was similar in both groups. Compared with group I, echocardiographic left ventricular ejection fraction (LVEF) and fractional area change (FAC) were higher while LV end-diastolic volume (LVEDV) and LV end-systolic and end-diastolic diameters (LVESD and LVEDD) were lower in treated rats. Hemodynamically, atorvastatin-treated rats exhibited significantly higher dP/dtmax, end-systolic elastance (Ees), and preload recruitable stroke work (PRSW) and lower LV end-diastolic pressure (LVEDP). Morphometrically, infarct wall thickness was greater in treated rats. The improvement of LV function by atorvastatin was associated with a decrease in hydroxyproline content and in the number of apoptotic cardiomyocyte nuclei. We conclude that atorvastatin therapy during the peri-infarct period significantly improves LV function and limits adverse LV remodeling following MI independent of a reduction in infarct size. These salubrious effects may be due in part to a decrease in myocardial fibrosis and apoptosis

Peg-interferon lambda treatment induces robust innate and adaptive immunity in chronic hepatitis B patients

IFN-lambda (IFNλ) is a member of the type III IFN family and is reported to possess anti-pathogen, anti-cancer, and immunomodulatory properties; however, there are limited data regarding its impact on host immune responses in vivo. We performed longitudinal and comprehensive immunosurveillance to assess the ability of pegylated (peg)-IFNλ to augment antiviral host immunity as part of a clinical trial assessing the efficacy of peg-IFNλ in chronic hepatitis B (CHB) patients. These patients were pretreated with directly acting antiviral therapy (entecavir) for 12 weeks with subsequent addition of peg-IFNλ for up to 32 weeks. In a subgroup of patients, the addition of peg-IFNλ provoked high serum levels of antiviral cytokine IL-18. We also observed the enhancement of natural killer cell polyfunctionality and the recovery of a pan-genotypic HBV-specific CD4+ T cells producing IFN-γ with maintenance of HBV-specific CD8+ T cell antiviral and cytotoxic activities. It was only in these patients that we observed strong virological control with reductions in both viral replication and HBV antigen levels. Here, we show for the first time that in vivo peg-IFNλ displays significant immunostimulatory properties with improvements in the main effectors mediating anti-HBV immunity. Interestingly, the maintenance in HBV-specific CD8+ T cells in the presence of peg-IFNλ is in contrast to previous studies showing that peg-IFNa treatment for CHB results in a detrimental effect on the functionality of this important antiviral T cell compartment

New roles for renin and prorenin in heart failure and cardiorenal crosstalk

The renin-angiotensin-aldosterone-system (RAAS) plays a central role in the pathophysiology of heart failure and cardiorenal interaction. Drugs interfering in the RAAS form the pillars in treatment of heart failure and cardiorenal syndrome. Although RAAS inhibitors improve prognosis, heart failure–associated morbidity and mortality remain high, especially in the presence of kidney disease. The effect of RAAS blockade may be limited due to the loss of an inhibitory feedback of angiotensin II on renin production. The subsequent increase in prorenin and renin may activate several alternative pathways. These include the recently discovered (pro-) renin receptor, angiotensin II escape via chymase and cathepsin, and the formation of various angiotensin subforms upstream from the blockade, including angiotensin 1–7, angiotensin III, and angiotensin IV. Recently, the direct renin inhibitor aliskiren has been proven effective in reducing plasma renin activity (PRA) and appears to provide additional (tissue) RAAS blockade on top of angiotensin-converting enzyme and angiotensin receptor blockers, underscoring the important role of renin, even (or more so) under adequate RAAS blockade. Reducing PRA however occurs at the expense of an increase plasma renin concentration (PRC). PRC may exert direct effects independent of PRA through the recently discovered (pro-) renin receptor. Additional novel possibilities to interfere in the RAAS, for instance using vitamin D receptor activation, as well as the increased knowledge on alternative pathways, have revived the question on how ideal RAAS-guided therapy should be implemented. Renin and prorenin are pivotal since these are at the base of all of these pathways

Prevalence of comorbidity of chronic diseases in Australia

<p>Abstract</p> <p>Background</p> <p>The prevalence of comorbidity is high, with 80% of the elderly population having three or more chronic conditions. Comorbidity is associated with a decline in many health outcomes and increases in mortality and use of health care resources. The aim of this study was to identify, review and summarise studies reporting the prevalence of comorbidity of chronic diseases in Australia.</p> <p>Methods</p> <p>A systematic review of Australian studies (1996 – May 2007) was conducted. The review focused specifically on the chronic diseases included as national health priorities; arthritis, asthma, cancer, cardiovascular disease (CVD), diabetes mellitus and mental health problems.</p> <p>Results</p> <p>A total of twenty five studies met our inclusion criteria. Over half of the elderly patients with arthritis also had hypertension, 20% had CVD, 14% diabetes and 12% mental health problem. Over 60% of patients with asthma reported arthritis as a comorbidity, 20% also had CVD and 16% diabetes. Of those with CVD, 60% also had arthritis, 20% diabetes and 10% had asthma or mental health problems.</p> <p>Conclusion</p> <p>There are comparatively few Australian studies that focused on comorbidity associated with chronic disease. However, they do show high prevalence of comorbidity across national health priority areas. This suggests integration and co-ordination of the national health priority areas is critical. A greater awareness of the importance of managing a patients' overall health status within the context of comorbidity is needed together with, increased research on comorbidity to provide an appropriate scientific basis on which to build evidence based care guidelines for these multimorbid patients.</p

Microparticles Carrying Sonic Hedgehog Favor Neovascularization through the Activation of Nitric Oxide Pathway in Mice

BACKGROUND: Microparticles (MPs) are vesicles released from plasma membrane upon cell activation and during apoptosis. Human T lymphocytes undergoing activation and apoptosis generate MPs bearing morphogen Shh (MPs(Shh+)) that are able to regulate in vitro angiogenesis.METHODOLOGY/PRINCIPAL FINDINGS: Here, we investigated the ability of MPs(Shh+) to modulate neovascularization in a model of mouse hind limb ischemia. Mice were treated in vivo for 21 days with vehicle, MPs(Shh+), MPs(Shh+) plus cyclopamine or cyclopamine alone, an inhibitor of Shh signalling. Laser doppler analysis revealed that the recovery of the blood flow was 1.4 fold higher in MPs(Shh+)-treated mice than in controls, and this was associated with an activation of Shh pathway in muscles and an increase in NO production in both aorta and muscles. MPs(Shh+)-mediated effects on flow recovery and NO production were completely prevented when Shh signalling was inhibited by cyclopamine. In aorta, MPs(Shh+) increased activation of eNOS/Akt pathway, and VEGF expression, being inhibited by cyclopamine. By contrast, in muscles, MPs(Shh+) enhanced eNOS expression and phosphorylation and decreased caveolin-1 expression, but cyclopamine prevented only the effects of MPs(Shh+) on eNOS pathway. Quantitative RT-PCR revealed that MPs(Shh+) treatment increased FGF5, FGF2, VEGF A and C mRNA levels and decreased those of α5-integrin, FLT-4, HGF, IGF-1, KDR, MCP-1, MT1-MMP, MMP-2, TGFβ1, TGFβ2, TSP-1 and VCAM-1, in ischemic muscles. CONCLUSIONS/SIGNIFICANCE: These findings suggest that MPs(Shh+) may contribute to reparative neovascularization after ischemic injury by regulating NO pathway and genes involved in angiogenesis

Cellular distribution of vascular endothelial growth factor A (VEGFA) and B (VEGFB) and VEGF receptors 1 and 2 in focal cortical dysplasia type IIB

Members of the vascular endothelial growth factor (VEGF) family are key signaling proteins in the induction and regulation of angiogenesis, both during development and in pathological conditions. However, signaling mediated through VEGF family proteins and their receptors has recently been shown to have direct effects on neurons and glial cells. In the present study, we immunocytochemically investigated the expression and cellular distribution of VEGFA, VEGFB, and their associated receptors (VEGFR-1 and VEGFR-2) in focal cortical dysplasia (FCD) type IIB from patients with medically intractable epilepsy. Histologically normal temporal cortex and perilesional regions displayed neuronal immunoreactivity (IR) for VEGFA, VEGFB, and VEGF receptors (VEGFR-1 and VEGFR-2), mainly in pyramidal neurons. Weak IR was observed in blood vessels and there was no notable glial IR within the grey and white matter. In all FCD specimens, VEGFA, VEGFB, and both VEGF receptors were highly expressed in dysplastic neurons. IR in astroglial and balloon cells was observed for VEGFA and its receptors. VEGFR-1 displayed strong endothelial staining in FCD. Double-labeling also showed expression of VEGFA, VEGFB and VEGFR-1 in cells of the microglia/macrophage lineage. The neuronal expression of both VEGFA and VEGFB, together with their specific receptors in FCD, suggests autocrine/paracrine effects on dysplastic neurons. These autocrine/paracrine effects could play a role in the development of FCD, preventing the death of abnormal neuronal cells. In addition, the expression of VEGFA and its receptors in glial cells within the dysplastic cortex indicates that VEGF-mediated signaling could contribute to astroglial activation and associated inflammatory reactions