Nox2-deficient Tregs improve heart transplant outcomes via their increased graft recruitment and enhanced potency.

Nox2 is a ROS-generating enzyme, deficiency of which increases suppression by Tregs in vitro and in an in vivo model of cardiac remodelling. Since Tregs have emerged as a candidate therapy in autoimmunity and transplantation, we hypothesised that Nox2 deficiency in Tregs in recipient mice may improve outcomes in a heart transplant model. A novel B6129 mouse model with Treg-targeted Nox2 deletion (Nox2fl/flFoxP3Cre+) was generated and transplanted with hearts from CB6F1 donors. As compared to littermate controls, Nox2fl/flFoxP3Cre+ mice had lower plasma levels of alloantibodies and troponin-I, reduced levels of IFN-γ in heart allograft homogenates and diminished cardiomyocyte necrosis and allograft fibrosis. Single cell analyses of allografts revealed higher absolute numbers of Tregs and lower CD8+ T cell infiltration in Nox2-deficient recipients compared to Nox2-replete mice. Mechanistically, in addition to a greater suppression of CD8+CD25- T effector cell proliferation and IFN-γ production, Nox2-deficient Tregs expressed higher levels of CCR4 and CCR8, driving cell migration to allografts; this was associated with increased expression of miR214-3p. These data indicate that Nox2 deletion in Tregs enhances their suppressive ability and migration to heart allografts. Therefore, Nox2 inhibition in Tregs may be a useful approach to improve their therapeutic efficacy

Chemical activation of SAT1 corrects diet-induced metabolic syndrome.

The pharmacological targeting of polyamine metabolism is currently under the spotlight for its potential in the prevention and treatment of several age-associated disorders. Here, we report the finding that triethylenetetramine dihydrochloride (TETA), a copper-chelator agent that can be safely administered to patients for the long-term treatment of Wilson disease, exerts therapeutic benefits in animals challenged with hypercaloric dietary regimens. TETA reduced obesity induced by high-fat diet, excessive sucrose intake, or leptin deficiency, as it reduced glucose intolerance and hepatosteatosis, but induced autophagy. Mechanistically, these effects did not involve the depletion of copper from plasma or internal organs. Rather, the TETA effects relied on the activation of an energy-consuming polyamine catabolism, secondary to the stabilization of spermidine/spermine N1-acetyltransferase-1 (SAT1) by TETA, resulting in enhanced enzymatic activity of SAT. All the positive effects of TETA on high-fat diet-induced metabolic syndrome were lost in SAT1-deficient mice. Altogether, these results suggest novel health-promoting effects of TETA that might be taken advantage of for the prevention or treatment of obesity

Pressure-Support Ventilation vs T-Piece During Spontaneous Breathing Trials Before Extubation Among Patients at High Risk of Extubation Failure

International audienceBackgroundSpontaneous breathing trial (SBT) using a T-piece remains the most frequently performed trial before extubation in ICUs.Research QuestionWe aimed at determining whether initial SBT using pressure-support ventilation (PSV) could increase successful extubation rates among patients at high risk of extubation failure.Study Design and MethodsPost hoc analysis of a multicenter trial focusing on reintubation in patients at high-risk of extubation failure. The initial SBT was performed using PSV or T-piece according to the physician/center decision. The primary outcome was the proportion of patients successfully extubated 72 hours after initial SBT, that is, extubated after initial SBT and not reintubated within the following 72 hours.ResultsAmong the 641 patients included in the original study, initial SBT was performed using PSV (7.0 cm H2O in median without positive end-expiratory pressure) in 243 patients (38%) and using a T-piece in 398 patients (62%). The proportion of patients successfully extubated 72 hours after initial SBT was 67% (162/243) using PSV and 56% (223/398) using T-piece (absolute difference 10.6%; 95% CI, 2.8 to 28.1; P = .0076). The proportion of patients extubated after initial SBT was 77% (186/283) using PSV and 63% (249/398) using T-piece (P = .0002), whereas reintubation rates within the following 72 hours did not significantly differ (13% vs 10%, respectively; P = .4259). Performing an initial SBT using PSV was independently associated with successful extubation (adjusted OR, 1.60; 95% CI, 1.30 to 2.18; P = .0061).InterpretationIn patients at high risk of extubation failure in the ICU, performing an initial SBT using PSV may hasten extubation without an increased risk of reintubation