The nitrite anion is reduced to nitric oxide (NO • ) as oxygen tension decreases. Whereas this pathway modulates hypoxic NO • signaling and mitochondrial respiration and limits myocardial infarction in mammalian species, the pathways to nitrite bioactivation remain uncertain. Studies suggest that hemoglobin and myoglobin may subserve a fundamental physiological function as hypoxia dependent nitrite reductases. Using myoglobin wild-type ( +/+ ) and knockout ( −/− ) mice, we here test the central role of myoglobin as a functional nitrite reductase that regulates hypoxic NO • generation, controls cellular respiration, and therefore confirms a cytoprotective response to cardiac ischemia-reperfusion (I/R) injury. We find that myoglobin is responsible for nitrite-dependent NO • generation and cardiomyocyte protein iron-nitrosylation. Nitrite reduction to NO • by myoglobin dynamically inhibits cellular respiration and limits reactive oxygen species generation and mitochondrial enzyme oxidative inactivation after I/R injury. In isolated myoglobin +/+ but not in myoglobin −/− hearts, nitrite treatment resulted in an improved recovery of postischemic left ventricular developed pressure of 29%. In vivo administration of nitrite reduced myocardial infarction by 61% in myoglobin +/+ mice, whereas in myoglobin −/− mice nitrite had no protective effects. These data support an emerging paradigm that myoglobin and the heme globin family subserve a critical function as an intrinsic nitrite reductase that regulates responses to cellular hypoxia and reoxygenation. myoglobin knockout mice

In the mammalian embryo, few mechanical signals have been identified to influence organ development and function. Here, we report that an increase in the volume of interstitial or extracellular fluid mechanically induces growth of an organ system, that is, the lymphatic vasculature. We first demonstrate that lymph vessel expansion in the developing mouse embryo correlates with a peak in interstitial fluid pressure and lymphatic endothelial cell (LEC) elongation. In 'loss-of-fluid' experiments, we then show that aspiration of interstitial fluid reduces the length of LECs, decreases tyrosine phosphorylation of vascular endothelial growth factor receptor-3 (VEGFR3), and inhibits LEC proliferation. Conversely, in 'gain-of-fluid' experiments, increasing the amount of interstitial fluid elongates the LECs, and increases both VEGFR3 phosphorylation and LEC proliferation. Finally, we provide genetic evidence that b1 integrins are required for the proliferative response of LECs to both fluid accumulation and cell stretching and, therefore, are necessary for lymphatic vessel expansion and fluid drainage. Thus, we propose a new and physiologically relevant mode of VEGFR3 activation, which is based on mechanotransduction and is essential for normal development and fluid homeostasis in a mammalian embryo.

Abstract-During myocardial reperfusion, polymorphonuclear neutrophil (PMN) adhesion involving the intercellular adhesion molecule-1 (ICAM-1) may lead to aggravation and prolongation of reperfusion injury. We studied the role of early tumor necrosis factor-␣ (TNF-␣) cleavage and nuclear factor-B (NF-B) activation on ICAM-1 expression and venular adhesion of PMN in isolated hearts after ischemia (15 minutes) and reperfusion (30 to 480 minutes). NF-B activation (electromobility shift assay) was found after 30 minutes of reperfusion and up to 240 minutes. ICAM-1 mRNA, assessed by Northern blot, increased during the same interval. Functional effect of newly synthesized adhesion molecules was found by quantification (in situ fluorescence microscopy) of PMN, given as bolus after ischemia, which became adherent to small coronary venules (10 to 50 m in diameter). After 480 minutes of reperfusion, ICAM-1-dependent PMN adhesion increased 2.5-fold compared with PMN adhesion obtained during acute reperfusion.To study the influence of NF-B on PMN adhesion, we inhibited NF-B activation by transfection of NF-B decoy oligonucleotides into isolated hearts using HJV-liposomes. Decoy NF-B but not control oligonucleotides blocked ICAM-1 upregulation and inhibited the subacute increase in PMN adhesion. Similar effects were obtained using BB 1101 (10 g), an inhibitor of TNF-␣ cleavage enzyme. These data suggest that ischemia and reperfusion in isolated hearts cause liberation of TNF-␣, activation of NF-B, and upregulation of ICAM-1, an adhesion molecule involved in inflammatory response after ischemia and reperfusion. (Circ Res. 1999;84:392-400.)

These results show that cardiomyopathies associated with heart failure transcribe substantially higher levels - on average by a factor of 30 - of CAR-mRNA than non-failing control hearts. Myocardial gene transfer using adenoviral vectors should therefore be facilitated in human cardiomyopathies and may present a promising approach for therapeutic interventions.

Although p38 MAP Kinase α (p38 MAPKα) is generally accepted to play a central role in the cardiac stress response, to date its function in maladaptive cardiac hypertrophy is still not unambiguously defined. To induce a pathological type of cardiac hypertrophy we infused angiotensin II (AngII) for 2 days via osmotic mini pumps in control and tamoxifen-inducible, cardiomyocyte (CM)-specific p38 MAPKα KO mice (iCMp38αKO) and assessed cardiac function by echocardiography, complemented by transcriptomic, histological, and immune cell analysis. AngII treatment after inactivation of p38 MAPKα in CM results in left ventricular (LV) dilatation within 48 h (EDV: BL: 83.8 ± 22.5 µl, 48 h AngII: 109.7 ± 14.6 µl) and an ectopic lipid deposition in cardiomyocytes, reflecting a metabolic dysfunction in pressure overload (PO). This was accompanied by a concerted downregulation of transcripts for oxidative phosphorylation, TCA cycle, and fatty acid metabolism. Cardiac inflammation involving neutrophils, macrophages, B- and T-cells was significantly enhanced. Inhibition of adipose tissue lipolysis by the small molecule inhibitor of adipocytetriglyceride lipase (ATGL) Atglistatin reduced cardiac lipid accumulation by 70% and neutrophil infiltration by 30% and went along with an improved cardiac function. Direct targeting of neutrophils by means of anti Ly6G-antibody administration in vivo led to a reduced LV dilation in iCMp38αKO mice and an improved systolic function (EF: 39.27 ± 14%). Thus, adipose tissue lipolysis and CM lipid accumulation augmented cardiac inflammation in iCMp38αKO mice. Neutrophils, in particular, triggered the rapid left ventricular dilatation. We provide the first evidence that p38 MAPKα acts as an essential switch in cardiac adaptation to PO by mitigating metabolic dysfunction and inflammation. Moreover, we identified a heart–adipose tissue–immune cell crosstalk, which might serve as new therapeutic target in cardiac pathologies.

Background: (335/350) ST-segment elevation myocardial infarction (STEMI) still causes significant mortality and morbidity despite best-practice revascularization and adjunct medical strategies. Within the STEMI population, there is a spectrum of higher and lower risk patients with respect to major adverse cardiovascular and cerebral events (MACCE) or re-hospitalization due to heart failure. Myocardial and systemic metabolic disorders modulate patient risk in STEMI. Systematic cardiocirculatory and metabolic phenotyping to assess the bidirectional interaction of cardiac and systemic metabolism in myocardial ischemia is lacking. Methods: Systemic organ communication in STEMI (SYSTEMI) is an all-comer open-end prospective study in STEMI patients >18 years of age to assess the interaction of cardiac and systemic metabolism in STEMI by systematically collecting data on a regional and systemic level. Primary endpoint will be myocardial function, left ventricular remodelling, myocardial texture and coronary patency at 6 month after STEMI. Secondary endpoint will be all-cause death, MACCE, and re-hospitalisation due to heart failure or revascularisation assessed 12 month after STEMI. The objective of SYSTEMI is to identify metabolic systemic and myocardial master switches that determine primary and secondary endpoints. In SYSTEMI 150-200 patients are expected to be recruited per year. Patient data will be collected at the index event, within 24 hours, 5 days as well as 6 and 12 months after STEMI. Data acquisition will be performed in multilayer approaches. Myocardial function will be assessed by using serial cardiac imaging with cineventriculography, echocardiography and cardiovascular magnetic resonance. Myocardial metabolism will be analysed by multi-nuclei magnetic resonance spectroscopy. Systemic metabolism will be approached by serial liquid biopsies and analysed with respect to glucose and lipid metabolism as well as oxygen transport. In summary, SYSTEMI enables a comprehensive data analysis on the levels of organ structure and function alongside hemodynamic, genomic and transcriptomic information to assess cardiac and systemic metabolism. Discussion: SYSTEMI aims to identify novel metabolic patterns and master-switches in the interaction of cardiac and systemic metabolism to improve diagnostic and therapeutic algorithms in myocardial ischemia for patient-risk assessment and tailored therapy.

Introduction Community-acquired pneumonia remains a common condition worldwide. It is associated with significant morbidity and mortality. The aim of this study was to evaluate conditions that could predict a poor outcome. Design Retrospective analyse of 69 patients admitted to the ICU from 1996 to 2003. Demographic data included age, sex and medical history. Etiologic agents, multiorgan dysfunction, nosocomial infections, SAPS II and PORT scores were recorded for each patient. For statistical analysis we used a t test, chi-square test and Mann-Whitney U test on SPSS ® . A value of P less than 0.05 was considered significant. Results Forty-seven patients were male and 22 patients were female. Mean age was 52 years. Sixty-seven percent had serious pre-morbid conditions including pulmonary disease (34.8%), cardiac problems (36.2%), diabetes (13%) and chronic liver disease (5.8%); 40.6% were smokers, drug abusers or alcohol dependents. Sixtyeight patients required invasive mechanical ventilation. The average length of ventilation was 13.5 days, median 8 days. The mean SAPS II score was 40.14 and the mean PORT score was 141. The mortality rate was 27.5% (SAPS II estimated mortality, 35%). Complications reported were ARDS (40.6%), septic shock (34.8%), acute renal failure (2.9%), cardiac arrest (8.7%) and nosocomial infeccions (46.4%). Mortality rates were higher for previous hepatic (75%) and metabolic (33%) diseases. We found a close association between crude mortality and SAPS II score (P = 0.003) and development of complications (P = 0.0028). Respiratory dysfunction (P = 0.006) and septic shock (P = 0.022) were most significantly related to mortality. No significant differences were founded regarding age, comorbidities, PORT score, etiologic agents, nosocomial infections and length of invasive mechanical ventilation. Conclusions Previous hepatic chronic disease was strictly related to higher mortality as well as isolation of MRSA. ARDS and septic shock predicted a poor outcome. SAPS II score was the best severity indicator of mortality. Objective It is known that the closed tracheal suction system (CTSS) produces less hemodynamic and gasometric deterioration than an open tracheal suction system (OTSS). Use is limited because no decrease in the incidence of ventilator-associated pneumonia (VAP) was found and also because it is more expensive. But, is daily periodic change of the CTSS necessary? The aim of this study was to analyze the incidence of VAP using a CTSS without periodic change versus an OTSS. Methods It is a prospective study of ICU patients from 1 January 2004 to 31 October 2004. Patients who required mechanical ventilation (MV) were randomized into two groups: one group was suctioned with CTSS without periodic change and another group with OTSS. An aspirate tracheal swab and a throat swab on admission and afterwards twice weekly were taken. VAP was classified based on throat flora in endogenous and exogenous samples. The statistical analysis was performed by chi-square test and Student's t test, and w...

Background Alternative splicing is a process by which exons within a pre-mRNA are joined or skipped, resulting in isoforms being encoded by a single gene. Alternative Splicing affecting transcription factors may have substantial impact on cellular dynamics. The PPARG Coactivator 1 Alpha (PGC1-α), is a major modulator in energy metabolism. Data from murine skeletal muscle revealed distinctive isoform patterns giving rise to different phenotypes, i.e. mitogenesis and hypertrophy. Here, we aimed to establish a complete dataset of isoforms in murine and human heart applying single-molecule real-time (SMRT)-sequencing as novel approach to identify transcripts without need for assembly, resulting in true full-length sequences. Moreover, we aimed to unravel functional relevance of the various isoforms during experimental ischemia reperfusion (I/R). Methods RNA-Isolation was performed in murine (C57Bl/6J) or human heart tissue (obtained during LVAD-surgery), followed by library preparation and SMRT-Sequencing. Bioinformatic analysis was done using a modified IsoSeq3-Pipeline and OS-tools. Identification of PGC1-α isoforms was fulfilled by similarity search against exonic sequences within the full-length, non-concatemere (FLNC) reads. Isoforms with Open-Reading-Frame (ORF) were manually curated and validated by PCR and Sanger-Sequencing. I/R was induced by ligature of the LAD for 45 min in mice on standard chow as well as on high-fat-high-sucrose diet. Area At Risk (AAR) and remote tissue were collected three and 16 days after I/R or sham-surgery (n=4 per time point). Promotor patterns were analyzed by qPCR. Results Deciphering the full-length transcriptome of murine and human heart resulted in ∼60000 Isoforms with 99% accuracy on mRNA-sequence. Focusing on murine PGC1-α-isoforms we discovered and verified 15 novel transcripts generated by hitherto unknown splicing events. Additionally, we identified a novel Exon 1 originating between the known promoters followed by a valid ORF, suggesting the discovery of a novel promoter. Remarkably, we found a homologous novel Exon1 in human heart, suggesting conservation of the postulated promoter. In I/R the AAR exhibited a significant lower expression of established and novel promoters compared to remote under standard chow 3d post I/R. 16d post I/R, the difference between AAR & Remote equalized in standard chow while remaining under High-Fat-Diet. Conclusion Applying SMRT-technique, we generated the first time a complete full-length-transcriptome of the murine and human heart, identifying 15 novel potentially coding transcripts of PGC1-α and a novel exon 1. These transcripts are differentially regulated in experimental I/R in AAR and remote myocardium, suggesting transcriptional regulation and alternative splicing modulating PGC1-α function in heart. Differences between standard chow and high fat diet suggest impact of impaired glucose metabolism on regulatory processes after myocardial infarction. Funding Acknowledgement Type of funding source: Public grant(s) – National budget only. Main funding source(s): Collaborative Research Centre 1116 (German Research Foundation)