The dawn of cardioprotection by infarct size reduction originated from the idea to favourably alter the oxygen demand–supply balance of the ischaemic/infarcting myocardium by reducing the contractile ...determinants of its oxygen consumption. This idea is probably not correct, since the ischaemic/infarcting myocardium does not contract anyway. None of the successful initial preclinical attempts of infarct size reduction translated into clinical practice, except for timely reperfusion which has become and still is the backbone of all clinical infarct therapy up today. The idea of cardioprotection gained momentum again with the recognition of ischaemic conditioning, and a myriad of preclinical studies have identified molecules and mechanisms of such self-defence mechanism. Although there are positive clinical proof-of-concept studies, ischaemic conditioning strategies and drugs related to its signal transduction have not translated into clinical practice. We are currently trying to understand the obstacles to translation from successful preclinical studies on cardioprotection to clinical practice, but are also waiting for an innovative mechanistic breakthrough.
Summary Although remote ischemic pre-conditioning (RIPC) reduced infarct size in animal experiments and proof-of-concept clinical trials, recent phase III trials failed to confirm cardioprotection ...during cardiac surgery. Here, we characterized the kinetic properties of humoral factors that are released after RIPC, as well as the signal transduction pathways that were responsible for cardioprotection in an ex vivo model of global ischemia reperfusion injury. Venous blood from 20 healthy volunteers was collected at baseline and 5 min, 30 min, 1 h, 6 h, and daily from 1 to 7 days after RIPC (3 × 5/5 min upper-limb ischemia/reperfusion). Plasma-dialysates (cut-off: 12 to 14 kDa; dilution: 1:20) were infused into Langendorff-perfused mouse hearts subjected to 20/120 min global ischemia/reperfusion. Infarct size and phosphorylation of signal transducer and activator of transcription (STAT)3, STAT5, extracellular-regulated kinase 1/2 and protein kinase B were determined. In a subgroup of plasma-dialysates, an inhibitor of STAT3 (Stattic) was used in mouse hearts. Perfusion with baseline-dialysate resulted in an infarct size of 39% of ventricular mass (interquartile range: 36% to 42%). Perfusion with dialysates obtained 5 min to 6 days after RIPC significantly reduced infarct size by ∼50% and increased STAT3 phosphorylation beyond that with baseline-dialysate. Inhibition of STAT3 abrogated these effects. These results suggest that RIPC induces the release of cardioprotective, dialyzable factor(s) within 5 min, and that circulate for up to 6 days. STAT3 is activated in murine myocardium by RIPC-induced human humoral factors and is causally involved in cardioprotection.
Abstract The damage inflicted on the myocardium during acute myocardial infarction is the result of 2 processes: ischemia and subsequent reperfusion (ischemia/reperfusion injury). During the last 3 ...decades, therapies to reduce ischemic injury (mainly reperfusion strategies) have been widely incorporated into clinical practice. The remarkable reduction in death rates achieved with these therapies has resulted in a shift in emphasis from efforts to reduce mortality to a focus on tackling the downstream consequence of survival: post-infarction heart failure. Infarct size is the main determinant of long-term mortality and chronic heart failure, and thus, the possibility of limiting the extent of necrosis during an ST-segment elevation myocardial infarction is of great individual and socioeconomic value. After the great success of therapies to reduce ischemic injury, the time has come to focus efforts on therapies to reduce reperfusion injury, but in the recent few years, few interventions have successfully passed the proof-of-concept stage. In this review, we examine the past, present, and future therapies to reduce ischemia/reperfusion injury.
Remote Ischemic Conditioning Heusch, Gerd, MD; Bøtker, Hans Erik, MD, PhD; Przyklenk, Karin, PhD ...
Journal of the American College of Cardiology,
01/2015, Volume:
65, Issue:
2
Journal Article
Peer reviewed
Open access
Abstract In remote ischemic conditioning (RIC), brief, reversible episodes of ischemia with reperfusion in one vascular bed, tissue, or organ confer a global protective phenotype and render remote ...tissues and organs resistant to ischemia/reperfusion injury. The peripheral stimulus can be chemical, mechanical, or electrical and involves activation of peripheral sensory nerves. The signal transfer to the heart or other organs is through neuronal and humoral communications. Protection can be transferred, even across species, with plasma-derived dialysate and involves nitric oxide, stromal derived factor-1α, microribonucleic acid-144, but also other, not yet identified factors. Intracardiac signal transduction involves: adenosine, bradykinin, cytokines, and chemokines, which activate specific receptors; intracellular kinases; and mitochondrial function. RIC by repeated brief inflation/deflation of a blood pressure cuff protects against endothelial dysfunction and myocardial injury in percutaneous coronary interventions, coronary artery bypass grafting, and reperfused acute myocardial infarction. RIC is safe and effective, noninvasive, easily feasible, and inexpensive.
Recent evidence suggests that in addition to their well known stimulatory properties, dendritic cells (DCs) may play a major role in peripheral tolerance. It is still unclear whether a distinct ...subtype or activation status of DC exists that promotes the differentiation of suppressor rather than effector T cells from naive precursors. In this work, we tested whether the naturally occurring CD4+ CD25+ regulatory T cells (Treg) may control immune responses induced by DCs in vivo. We characterized the immune response induced by adoptive transfer of antigen-pulsed mature DCs into mice depleted or not of CD25+ cells. We found that the development of major histocompatibility complex class I and II-restricted interferon gamma-producing cells was consistently enhanced in the absence of Treg. By contrast, T helper cell (Th)2 priming was down-regulated in the same conditions. This regulation was independent of interleukin 10 production by DCs. Of note, splenic DCs incubated in vitro with Toll-like receptor ligands (lipopolysaccharide or CpG) activated immune responses that remained sensitive to Treg function. Our data further show that mature DCs induced higher cytotoxic activity in CD25-depleted recipients as compared with untreated hosts. We conclude that Treg naturally exert a negative feedback mechanism on Th1-type responses induced by mature DCs in vivo.
The future
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experiment aims to search for new physics in the electroweak sector by measuring the Coherent Elastic Neutrino-Nucleus Scattering process from reactor antineutrinos with high ...precision down to the sub-100 eV nuclear recoil energy range. While the
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collaboration is currently building the experimental setup at the reactor site, it is also finalizing the cryogenic detector arrays that will be integrated into the cryostat at the Institut Laue Langevin in early 2024. In this paper, we report on recent progress from the Ge cryogenic detector technology, called the CryoCube. More specifically, we present the first demonstration of a 30 eVee (electron equivalent) baseline ionization resolution (RMS) achieved with an early design of the detector assembly and its dedicated High Electron Mobility Transistor (HEMT) based front-end electronics with a total input capacitance of about 40 pF. This represents an order of magnitude improvement over the best ionization resolutions obtained on similar phonon-and-ionization germanium cryogenic detectors from the EDELWEISS and SuperCDMS dark matter experiments, and a factor of three improvement compared to the first fully-cryogenic HEMT-based preamplifier coupled to a CDMS-II germanium detector with a total input capacitance of 250 pF. Additionally, we discuss the implications of these results in the context of the future
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experiment and its expected background mitigation performance.
The morphology and the interface features of WC grains are examined by SEM and TEM in cemented carbides WC‐8 wt% Co. Three compositions — the mixture {WC + Co binder} and the mixtures with graphite ...or η — are studied after treatments at 1200 and 1450 °C. The effect of the C content is observed both on the WC crystal features and on the microstructure evolution. In all the alloys, large faceted grains that are defect free single crystals are formed at 1450 °C. On the C rich side, the increase in number and size of the large grains is more regular, the WC grains are more faceted and grow already during heating. On the W rich side, the WC grains have slightly rounded corners and interface steps. The C content influence on the interface energy anisotropy and the growth process of the WC grains is discussed from the microstructure results.
Ricochet Progress and Status Augier, C.; Beaulieu, G.; Belov, V. ...
Journal of low temperature physics,
08/2023, Volume:
212, Issue:
3-4
Journal Article
Peer reviewed
Open access
We present an overview of recent progress toward the
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coherent elastic neutrino nucleus scattering (CE
ν
NS) experiment. The ILL research reactor in Grenoble, France has been selected as the ...experiment site, after in situ studies of vibration and particle backgrounds. We present background rate estimates specific to that site, along with descriptions of the planned CryoCube and Q-Array detector payloads.
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