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Cytokine release syndrome (CRS) is a life-threatening complication of several new immunotherapies used to treat cancers and autoimmune diseases 1 – 5 . Here we report that atrial natriuretic peptide can protect mice from CRS induced by such agents by reducing the levels of circulating catecholamines. Catecholamines were found to orchestrate an immunodysregulation resulting from oncolytic bacteria and lipopolysaccharide through a self-amplifying loop in macrophages. Myeloid-specific deletion of tyrosine hydroxylase inhibited this circuit. Cytokine release induced by T-cell-activating therapeutic agents was also accompanied by a catecholamine surge and inhibition of catecholamine synthesis reduced cytokine release in vitro and in mice. Pharmacologic catecholamine blockade with metyrosine protected mice from lethal complications of CRS resulting from infections and various biotherapeutic agents including oncolytic bacteria, T-cell-targeting antibodies and CAR-T cells. Our study identifies catecholamines as an essential component of the cytokine release that can be modulated by specific blockers without impairing the therapeutic response. Atrial natriuretic peptide, an anti-inflammatory protein, can protect against cytokine release syndrome induced by therapeutic agents such as tumour-targeting bacteria and CAR-T cells by blocking catecholamine synthesis by macrophages.

Lipolysis declines with age because NLRP3 inflammasome-activated adipose tissue macrophages reduce levels of noradrenaline by upregulating genes that control its degradation, such as GDF3 and MAOA . The age old problem of fat breakdown With increasing age, lipolysis (the breakdown of fats in the body) induced by catecholamines declines and fewer free fatty acids are mobilized. This is associated with increased fat around the abdomen, a lower exercise capacity, and a reduced ability to maintain core body temperature and to survive starvation. Vishwa Deep Dixit and colleagues now show that lipolysis declines because fatty tissue macrophages activated by NLRP3 inflammasome reduce the levels of catecholamine by upregulating genes that control its degradation, such as growth differentiation factor-3 (GDF3) and monoamine oxidase A (MAOA). Deletion of NLRP3 or GDF3, or inhibition of MAOA restores lipolysis to more youthful levels. Catecholamine-induced lipolysis, the first step in the generation of energy substrates by the hydrolysis of triglycerides 1 , declines with age 2 , 3 . The defect in the mobilization of free fatty acids in the elderly is accompanied by increased visceral adiposity, lower exercise capacity, failure to maintain core body temperature during cold stress, and reduced ability to survive starvation. Although catecholamine signalling in adipocytes is normal in the elderly, how lipolysis is impaired in ageing remains unknown 2 , 4 . Here we show that adipose tissue macrophages regulate the age-related reduction in adipocyte lipolysis in mice by lowering the bioavailability of noradrenaline. Unexpectedly, unbiased whole-transcriptome analyses of adipose macrophages revealed that ageing upregulates genes that control catecholamine degradation in an NLRP3 inflammasome-dependent manner. Deletion of NLRP3 in ageing restored catecholamine-induced lipolysis by downregulating growth differentiation factor-3 (GDF3) and monoamine oxidase A (MAOA) that is known to degrade noradrenaline. Consistent with this, deletion of GDF3 in inflammasome-activated macrophages improved lipolysis by decreasing levels of MAOA and caspase-1. Furthermore, inhibition of MAOA reversed the age-related reduction in noradrenaline concentration in adipose tissue, and restored lipolysis with increased levels of the key lipolytic enzymes adipose triglyceride lipase (ATGL) and hormone sensitive lipase (HSL). Our study reveals that targeting neuro-immunometabolic signalling between the sympathetic nervous system and macrophages may offer new approaches to mitigate chronic inflammation-induced metabolic impairment and functional decline.

Background Elevated catecholamine levels might be associated with unfavorable outcome after traumatic brain injury (TBI). We investigated the association between catecholamine levels in the first 24 h post-trauma and functional outcome in patients with isolated moderate-to-severe TBI. Methods A cohort of 174 patients who sustained isolated blunt TBI was prospectively enrolled from three Level-1 Trauma Centers. Epinephrine (Epi) and norepinephrine (NE) concentrations were measured at admission (baseline), 6, 12 and 24 h post-injury. Outcome was assessed at 6 months by the extended Glasgow Outcome Scale (GOSE) score. Fractional polynomial plots and logistic regression models (fixed and random effects) were used to study the association between catecholamine levels and outcome. Effect size was reported as the odds ratio (OR) associated with one logarithmic change in catecholamine level. Results At 6 months, 109 patients (62.6%) had an unfavorable outcome (GOSE 5–8 vs. 1–4), including 51 deaths (29.3%). Higher admission levels of Epi were associated with a higher risk of unfavorable outcome (OR, 2.04, 95% CI: 1.31–3.18, p  = 0.002) and mortality (OR, 2.86, 95% CI: 1.62–5.01, p  = 0.001). Higher admission levels of NE were associated with higher risk of unfavorable outcome (OR, 1.59, 95% CI: 1.07–2.35, p  = 0.022) but not mortality (OR, 1.45, 95% CI: 0.98–2.17, p  = 0.07). There was no relationship between the changes in Epi levels over time and mortality or unfavorable outcome. Changes in NE levels with time were statistically associated with a higher risk of mortality, but the changes had no relation to unfavorable outcome. Conclusions Elevated circulating catecholamines, especially Epi levels on hospital admission, are independently associated with functional outcome and mortality after isolated moderate-to-severe TBI.

In a multicenter trial, 778 patients with septic shock who were being treated with catecholamine vasopressors were randomly assigned to either norepinephrine or vasopressin in addition to open-label vasopressors. There was no significant difference between the two groups in mortality at either 28 or 90 days, nor was there any significant difference in the rate of adverse events. Patients with septic shock were randomly assigned to either norepinephrine or vasopressin in addition to open-label vasopressors. There was no significant difference between the two groups in mortality at either 28 or 90 days. Septic shock is the most common cause of death in intensive care units (ICUs) 1 , 2 and has a mortality rate of 40 to 60%. 2 , 3 Resuscitation strategies include the administration of intravenous fluids and the use of catecholamines such as norepinephrine, epinephrine, dopamine, and dobutamine. 4 , 5 Although largely effective in reestablishing minimally acceptable mean arterial pressures to maintain organ perfusion, catecholamines have important adverse effects and may even increase mortality rates. 6 For example, norepinephrine, a potent and commonly used α-adrenergic agent in cases of septic shock, may decrease cardiac output, oxygen delivery, and blood flow to vulnerable organs despite adequate . . .

Patients with vasodilatory shock were randomly assigned to angiotensin II or placebo. At 3 hours, more patients in the angiotensin II group than in the placebo group had an increase in mean arterial pressure of at least 10 mm Hg or to at least 75 mm Hg.

Post-cardiac surgery shock is associated with high morbidity and mortality. By removing toxins and proinflammatory mediators and correcting metabolic acidosis, high-volume hemofiltration (HVHF) might halt the vicious circle leading to death by improving myocardial performance and reducing vasopressor dependence. To determine whether early HVHF decreases all-cause mortality 30 days after randomization. This prospective, multicenter randomized controlled trial included patients with severe shock requiring high-dose catecholamines 3-24 hours post-cardiac surgery who were randomized to early HVHF (80 ml/kg/h for 48 h), followed by standard-volume continuous venovenous hemodiafiltration (CVVHDF) until resolution of shock and recovery of renal function, or conservative standard care, with delayed CVVHDF only for persistent, severe acute kidney injury. On Day 30, 40 of 112 (36%) HVHF and 40 of 112 (36%) control subjects (odds ratio, 1.00; 95% confidence interval, 0.64-1.56; P = 1.00) had died; only 57% of the control subjects had received renal-replacement therapy. Between-group survivors' Day-60, Day-90, intensive care unit, and in-hospital mortality rates, Day-30 ventilator-free days, and renal function recovery were comparable. HVHF patients experienced faster correction of metabolic acidosis and tended to be more rapidly weaned off catecholamines but had more frequent hypophosphatemia, metabolic alkalosis, and thrombocytopenia. For patients with post-cardiac surgery shock requiring high-dose catecholamines, the early HVHF onset for 48 hours, followed by standard volume until resolution of shock and recovery of renal function, did not lower Day-30 mortality and did not impact other important patient-centered outcomes compared with a conservative strategy with delayed CVVHDF initiation only for patients with persistent, severe acute kidney injury. Clinical trial registered with www.clinicaltrials.gov (NCT 01077349).

Catecholamines are used to increase cardiac output and blood pressure, aiming ultimately at restoring/improving tissue perfusion. While intuitive in its concept, this approach nevertheless implies to be effective that regional organ perfusion would increase in parallel to cardiac output or perfusion pressure and that the catecholamine does not have negative effects on the microcirculation. Inotropic agents may be considered in some conditions, but it requires prior optimization of cardiac preload. Alternative approaches would be either to minimize exposure to vasopressors, tolerating hypotension and trying to prioritize perfusion but this may be valid as long as perfusion of the organ is preserved, or to combine moderate doses of vasopressors to vasodilatory agents, especially if these are predominantly acting on the microcirculation. In this review, we will discuss the pros and cons of the use of catecholamines and alternative agents for improving tissue perfusion in septic shock.

Trace-amine-associated receptors (TAARs), a group of biogenic amine receptors, have essential roles in neurological and metabolic homeostasis 1 . They recognize diverse endogenous trace amines and subsequently activate a range of G-protein-subtype signalling pathways 2 , 3 . Notably, TAAR1 has emerged as a promising therapeutic target for treating psychiatric disorders 4 , 5 . However, the molecular mechanisms underlying its ability to recognize different ligands remain largely unclear. Here we present nine cryo-electron microscopy structures, with eight showing human and mouse TAAR1 in a complex with an array of ligands, including the endogenous 3-iodothyronamine, two antipsychotic agents, the psychoactive drug amphetamine and two identified catecholamine agonists, and one showing 5-HT 1A R in a complex with an antipsychotic agent. These structures reveal a rigid consensus binding motif in TAAR1 that binds to endogenous trace amine stimuli and two extended binding pockets that accommodate diverse chemotypes. Combined with mutational analysis, functional assays and molecular dynamic simulations, we elucidate the structural basis of drug polypharmacology and identify the species-specific differences between human and mouse TAAR1. Our study provides insights into the mechanism of ligand recognition and G-protein selectivity by TAAR1, which may help in the discovery of ligands or therapeutic strategies for neurological and metabolic disorders. TAAR1 has a rigid consensus binding motif that binds to endogenous trace amine stimuli as well as two extended binding pockets that accommodate diverse chemotypes.

The skeletal muscle mass has been shown to be affected by catecholamines, such as epinephrine (Epi), norepinephrine (NE), and isoproterenol (ISO). On the other hand, lipopolysaccharide (LPS), one of the causative substances of sepsis, induces muscle wasting via toll-like receptors expressed in skeletal muscle. Although catecholamines are frequently administered to critically ill patients, it is still incompletely understood how these drugs affect skeletal muscle during critical illness, including sepsis. Herein, we examined the direct effects of catecholamines on LPS-induced skeletal muscle wasting using the C2C12 myoblast cell line. Muscle wasting induced by catecholamines and/or LPS was analyzed by the use of the differentiated C2C12 myotubes, and its underlying mechanism was explored by immunoblotting analysis, quantitative reverse transcription polymerase chain reaction (qRT-PCR), enzyme-linked immunosorbent assay (ELISA), and the TransAM kit for p-65 NF-[kappa]B. Epi augmented myosin heavy chain (MHC) protein loss and reduction of the myotube diameter induced by LPS. LPS induced C/EBP[delta] protein, Atrogin-1 and inteleukin-6 (IL-6), and these responses were potentiated by Epi. An IL-6 inhibitor, LMT28, suppressed the potentiating effect of Epi on the LPS-induced responses. NF-[kappa]B activity was induced by LPS, but was not affected by Epi and recombinant IL-6, and the NF-[kappa]B inhibitor, Bay 11-7082, abolished Atrogin-1 mRNA expression induced by LPS with or without Epi. NE and ISO also potentiated LPS-induced IL-6 and Atroign-1 mRNA expression. Carvedilol, a nonselective [beta]-adrenergic receptor antagonist, suppressed the facilitating effects of Epi on the Atrogin-1 mRNA induction by LPS, and abolished the effects of Epi on the MHC protein loss in the presence of LPS. It was concluded that Epi activates the [beta]-adrenergic receptors in C2C12 myotubes and the IL-6-STAT3 pathway, leading to the augmentation of LPS-induced activation of the NF-[kappa]B- C/EBP[delta]-Atrogin-1 pathway and to the exacerbation of myotube wasting.