Tissue functions mediated by β3-adrenoceptors—findings and challenges

As β3-adrenoceptor agonists metamorphose from experimental tools into therapeutic drugs, it is vital to obtain a comprehensive picture of the cell and tissue functions mediated by this receptor subtype in humans. Human tissues with proven functions and/or a high expression of β3-adrenoceptors include the urinary bladder, the gall bladder, and other parts of the gastrointestinal tract. While several other β3-adrenoceptor functions have been proposed based on results obtained in animals, their relevance to humans remains uncertain. For instance, β3-adrenoceptors perform an important role in thermogenesis and lipolysis in rodent brown and white adipose tissue, respectively, but their role in humans appears less significant. Moreover, the use of tools such as the agonist BRL 37344 and the antagonist SR59230A to demonstrate functional involvement of β3-adrenoceptors may lead in many cases to misleading conclusions as they can also interact with other β-adrenoceptor subtypes or even non-adrenoceptor targets. In conclusion, we propose that many responses attributed to β3-adrenoceptor stimulation may need re-evaluation in the light of the development of more selective tools. Moreover, findings in experimental animals need to be extended to humans in order to better understand the potential additional indications and side effects of the β3-adrenoceptor agonists that are beginning to enter clinical medicine

Blood pressure monitoring during arrhythmia: agreement between automated brachial cuff and intra-arterial measurements

International audienceBACKGROUND:Since arrhythmia induces irregular pulse waves, it is widely considered to cause flawed oscillometric brachial cuff measurements of blood pressure (BP). However, strong data are lacking. We assessed whether the agreement of oscillometric measurements with intra-arterial measurements is worse during arrhythmia than during regular rhythm.METHODS:Among patients of three intensive care units (ICUs), a prospective comparison of three pairs of intra-arterial and oscillometric BP readings was performed among patients with arrhythmia and an arterial line already present. After each inclusion in the arrhythmia group, one patient with regular rhythm was included as a control. International Organization for Standardization (ISO) standard validation required a mean bias 10 mm Hg) in our ICU population. The ability of oscillometry to detect hypotension (systolic BP 10% increase in mean BP after cardiovascular intervention) and hypertension (systolic BP >140 mm Hg) was good and similar during arrhythmia and regular rhythm (respective areas under the receiver operating characteristic curves ranging from 0.89 to 0.96, arrhythmia vs regular rhythm between-group comparisons all associated with P>0.3).CONCLUSIONS:Contrary to widespread belief, arrhythmia did not cause flawed automated brachial cuff measurements

The Secretome Deregulations in a Rat Model of Endotoxemic Shock

International audienceIntroduction. Septic shock is a systemic inflammatory response syndrome associated with organ failures. Earlier clinical diagnosis would be of benefit to a decrease in the mortality rate. However, there is currently a lack of predictive biomarkers. The secretome is the set of proteins secreted by a cell, tissue, or organism at a given time and under certain conditions. The plasma secretome is easily accessible from biological fluids and represents a good opportunity to discover new biomarkers that can be studied with nontargeted “omic” strategies. Aims. To identify relevant deregulated proteins (DEP) in the secretome of a rat endotoxemic shock model. Methods. Endotoxemic shock was induced in rats by intravenous injection of lipopolysaccharides (LPS, S. enterica typhi, 0.5 mg/kg) and compared to controls (Ringer Lactate, iv). Under isoflurane anesthesia, carotid cannulation allowed mean arterial blood pressure (MAP) and heart rate (HR) monitoring and blood sampling at different time points (T0 and T50 or T0 and T90, with EDTA and protease inhibitor). Samples were prepared for large-scale tandem mass spectrometry (MS-MS) based on a label-free quantification to allow identification of the proteins deregulated upon endotoxemic conditions. A Gene Ontology (GO) analysis defined several clusters of biological processes (BP) in which the DEP are involved. Results. Ninety minutes after shock induction, the LPS group presents a reduction in MAP (-45%, p < 0.05 ) and increased lactate levels (+27.5%, p < 0.05 ) compared to the control group. Proteomic analyses revealed 10 and 33 DEP in the LPS group, respectively, at 50 and 90 minutes after LPS injection. At these time points, GO-BP showed alterations in pathways involved in oxidative stress response and coagulation. Conclusion. This study proposes an approach to identify relevant DEP in septic shock and brings new insights into the understanding of the secretome adaptations upon sepsis

Prevention of early ventilation-acquired pneumonia (VAP) in comatose brain-injured patients by a single dose of ceftriaxone: PROPHY-VAP study protocol, a multicentre, randomised, double-blind, placebo-controlled trial

International audienceIntroduction: Ventilator-associated pneumonia (VAP) is the first cause of healthcare-associated infections in intensive care units (ICUs) and brain injury is one of the main risk factors for early-onset VAP. Antibiotic prophylaxis has been reported to decrease their occurrence in brain-injured patients, but a lack of controlled randomised trials and the risk of induction of bacterial resistance explain the low level of recommendations. The goal of this study is to determine whether a single dose of ceftriaxone within the 12 hours postintubation after severe brain injury can decrease the risk of early-onset VAP.Methods and analysis: The PROPHY-VAP is a French multicentre, randomised, double-blind, placebo-controlled, clinical trial. Adult brain-injured patients (n=320) with a Glasgow Coma Scale ≤12, requiring mechanical ventilation for more than 48 hours, are randomised to receive either a single dose of ceftriaxone 2 g or a placebo within the 12 hours after tracheal intubation. The primary endpoint is the proportion of patients developing VAP from the 2nd to the 7th day after mechanical ventilation. Secondary endpoints include the proportion of patients developing late VAP (>7 days after tracheal intubation), the number of ventilator-free days, VAP-free days and antibiotic-free days, length of stay in the ICU, proportion of patients with ventilator-associated events and mortality during their ICU stay.Ethics and dissemination: The initial research project was approved by the Institutional Review Board of OUEST III (France) on 20 October 2014 (registration No 2014-001668-36) and carried out according to the principles of the Declaration of Helsinki and the Clinical Trials Directive 2001/20/EC of the European Parliament relating to the Good Clinical Practice guidelines. The results of this study will be presented in national and international meetings and published in an international peer-reviewed journal