The stable AAP analogue ZP123 increased gap junctional intercellular conductance and specifically prevented the induction of reentrant VT during ischemia in a broad dose range without proarrhythmic or hemodynamic side effects. ZP123 is a promising candidate for use in preventing ischemia-induced VT.

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IMPORTANCE Norepinephrine, the first-line vasopressor for septic shock, is not always effective and has important catecholaminergic adverse effects. Selepressin, a selective vasopressin V1a receptor agonist, is a noncatecholaminergic vasopressor that may mitigate sepsis-induced vasodilatation, vascular leakage, and edema, with fewer adverse effects.OBJECTIVE To test whether selepressin improves outcome in septic shock. DESIGN, SETTING, AND PARTICIPANTSAn adaptive phase 2b/3 randomized clinical trial comprising 2 parts that included adult patients (n = 868) with septic shock requiring more than 5 μg/min of norepinephrine. Part 1 used a Bayesian algorithm to adjust randomization probabilities to alternative selepressin dosing regimens and to trigger transition to part 2, which would compare the best-performing regimen with placebo. The trial was conducted between July 2015 and August 2017 in 63 hospitals in Belgium, Denmark, France, the Netherlands, and the United States, and follow-up was completed by May 2018.INTERVENTIONS Random assignment to 1 of 3 dosing regimens of selepressin (starting infusion rates of 1.7, 2.5, and 3.5 ng/kg/min; n = 585) or to placebo (n = 283), all administered as continuous infusions titrated according to hemodynamic parameters. MAIN OUTCOMES AND MEASURESPrimary end point was ventilator-and vasopressor-free days within 30 days (deaths assigned zero days) of commencing study drug. Key secondary end points were 90-day mortality, kidney replacement therapy-free days, and ICU-free days. RESULTS Among 868 randomized patients, 828 received study drug (mean age, 66.3 years; 341 [41.2%] women) and comprised the primary analysis cohort, of whom 562 received 1 of 3 selepressin regimens, 266 received placebo, and 817 (98.7%) completed the trial. The trial was stopped for futility at the end of part 1. Median study drug duration was 37.8 hours (IQR,). There were no significant differences in the primary end point (ventilator-and vasopressor-free days: 15.0 vs 14.5 in the selepressin and placebo groups;

BackgroundVasopressin is widely used for vasopressor support in septic shock patients, but experimental evidence suggests that selective V1A agonists are superior. The initial pharmacodynamic effects, pharmacokinetics, and safety of selepressin, a novel V1A-selective vasopressin analogue, was examined in a phase IIa trial in septic shock patients.MethodsThis was a randomized, double-blind, placebo-controlled multicenter trial in 53 patients in early septic shock (aged ≥18 years, fluid resuscitation, requiring vasopressor support) who received selepressin 1.25 ng/kg/minute (n = 10), 2.5 ng/kg/minute (n = 19), 3.75 ng/kg/minute (n = 2), or placebo (n = 21) until shock resolution or a maximum of 7 days. If mean arterial pressure (MAP) ≥65 mmHg was not maintained, open-label norepinephrine was added. Co-primary endpoints were maintenance of MAP >60 mmHg without norepinephrine, norepinephrine dose, and proportion of patients maintaining MAP >60 mmHg with or without norepinephrine over 7 days. Secondary endpoints included cumulative fluid balance, organ dysfunction, pharmacokinetics, and safety.ResultsA higher proportion of the patients receiving 2.5 ng/kg/minute selepressin maintained MAP >60 mmHg without norepinephrine (about 50% and 70% at 12 and 24 h, respectively) vs. 1.25 ng/kg/minute selepressin and placebo (p < 0.01). The 7-day cumulative doses of norepinephrine were 761, 659, and 249 μg/kg (placebo 1.25 ng/kg/minute and 2.5 ng/kg/minute, respectively; 2.5 ng/kg/minute vs. placebo; p < 0.01). Norepinephrine infusion was weaned more rapidly in selepressin 2.5 ng/kg/minute vs. placebo (0.04 vs. 0.18 μg/kg/minute at 24 h, p < 0.001), successfully maintaining target MAP and reducing norepinephrine dose vs. placebo (first 24 h, p < 0.001). Cumulative net fluid balance was lower from day 5 onward in the selepressin 2.5 ng/kg/minute group vs. placebo (p < 0.05). The selepressin 2.5 ng/kg/minute group had a greater proportion of days alive and free of ventilation vs. placebo (p < 0.02). Selepressin (2.5 ng/kg/minute) was well tolerated, with a similar frequency of treatment-emergent adverse events for selepressin 2.5 ng/kg/minute and placebo. Two patients were infused at 3.75 ng/kg/minute, one of whom had the study drug infusion discontinued for possible safety reasons, with subsequent discontinuation of this dose group.ConclusionsIn septic shock patients, selepressin 2.5 ng/kg/minute was able to rapidly replace norepinephrine while maintaining adequate MAP, and it may improve fluid balance and shorten the time of mechanical ventilation.Trial registrationClinicalTrials.gov, NCT01000649. Registered on September 30, 2009.Electronic supplementary materialThe online version of this article (doi:10.1186/s13054-017-1798-7) contains supplementary material, which is available to authorized users.

Abstract:The angiotensin II (AngII) type 1 receptor (AT 1 R) has been shown to activate extracellular signal-regulated kinases 1 and 2 (ERK1/2) through G proteins or G protein-independently through β -arrestin2 in cellular expression systems. As activation mechanisms may greatly influence the biological effects of ERK1/2 activity, differential activation of the AT 1 R in its native cellular context could have important biological and pharmacological implications. To examine if AT 1 R activates ERK1/2 by G protein-independent mechanisms in the heart, we used the [Sar 1 , Ile 4 , Ile 8 ]-AngII ([SII] AngII) analogue in native preparations of cardiac myocytes and beating hearts. We found that [SII] AngII does not activate G q -coupling, yet stimulates the β -arrestin2-dependent ERK1/2. The G q -activated pool of ERK1/2 rapidly translocates to the nucleus, while the β -arrestin2-scaffolded pool remains in the cytosol. Similar biased agonism was achieved in Langendorffperfused hearts, where both agonists elicit ERK1/2 phosphorylation, but [SII] AngII induces neither inotropic nor chronotropic effects.