Summary. Background: Based on in vitro and animal data, PI3Kb is given an important role in platelet adhesion and aggregation but its role in insulin signaling is unclear. Objective: To strengthen the PI3Kb target validation using the novel, short-acting inhibitor AZD6482. Methods and results: AZD6482 is a potent, selective and ATP competitive PI3Kb inhibitor (IC 50 0.01 lM). A maximal anti-platelet effect was achieved at 1 lM in the in vitro and ex vivo tests both in dog and in man. In dog, in vivo AZD6482 produced a complete antithrombotic effect without an increased bleeding time or blood loss. AZD6482 was well tolerated in healthy volunteers during a 3-h infusion. The ex vivo anti-platelet effect and minimal bleeding time prolongation in the dog model translated well to data obtained in healthy volunteers. AZD6482 inhibited insulin-induced human adipocyte glucose uptake in vitro (IC 50 of 4.4 lM). In the euglycemic hyperinsulinemic clamp model, in rats, glucose infusion rate was not affected at 2.3 lM but reduced by about 60% at a plasma exposure of 27 lM. In man, the homeostasis model analysis (HOMA) index increased by about 10-20% at the highest plasma concentration of 5.3 lM. Conclusions: This is the first human target validation for PI3Kb inhibition as anti-platelet therapy showing a mild and generalized antiplatelet effect attenuating but not completely inhibiting multiple signaling pathways with an impressive separation towards primary hemostasis. AZD6482 at Ôsupra-therapeuticÕ plasma concentrations may attenuate insulin signaling, most likely through PI3Ka inhibition.

Highlights d Mature adipocytes cultured as MAAC preserve cellular identity and function d Subcutaneous and visceral adipocytes can be cultured as MAAC d Adipocytes from lean and obese donors can be cultured d Human mature white adipocytes can transdifferentiate into brown-like adipocytes

We describe multiwell assays for detecting the accumulation as well as the subsequent oxidation of 14

Aims In heart failure (HF) with preserved ejection fraction (HFpEF), microvascular inflammation is proposed as an underlying mechanism. Myeloperoxidase (MPO) is associated with vascular dysfunction and prognosis in congestive HF. Methods and results MPO, MPO-related biomarkers, and echocardiography were assessed in 86 patients, 4-8 weeks after presentation with acute HF (EF ≥ 45%), and in 46 healthy controls. Patients were followed up for median 579 days (Q1;Q3 276;1178) regarding the composite endpoint all-cause mortality or HF hospitalization. Patients were 73 years old, 51% were female, EF was 64% (Q1;Q3 58;68), E/e′ was ratio 10.8 (8.3;14.0), and left atrial volume index (LAVI) was 43 mL/m 2 (38;52). Controls were 60 (57;62) years old (vs. patients; P < 0.001), 24% were female (P = 0.005), and left ventricular EF was 63% (59;66; P = 0.790). MPO was increased in HFpEF compared with controls, 101 (81;132) vs. 86 (74;101 ng/mL, P = 0.015), as was uric acid 369 (314;439) vs. 289 (252;328 μmol/L, P < 0.001), calprotectin, asymmetric dimethyl arginine (ADMA), and symmetric dimethyl arginine (SDMA), while arginine was decreased. MPO correlated with uric acid (r = 0.26; P = 0.016). In patients with E/e′ > 14, uric acid and SDMA were elevated (421 vs. 344 μM, P = 0.012; 0.54 vs. 0.47 μM, P = 0.039, respectively), and MPO was 121 vs. 98 ng/mL (P = 0.090). The ratios of arginine/ADMA (112 vs. 162; P < 0.001) and ADMA/SDMA (1.36 vs. 1.17; P = 0.002) were decreased in HFpEF patients, suggesting reduced NO availability and increased enzymatic clearance of ADMA, respectively. Uric acid independently predicted the endpoint [hazard ratio (HR) 3.76 (95% CI 1.19-11.85; P = 0.024)] but not MPO [HR 1.48 (95% CI 0.70-3.14; P = 0.304)] or the other biomarkers. Conclusions In HFpEF, MPO-dependent oxidative stress reflected by uric acid and calprotectin is increased, and SDMA is associated with diastolic dysfunction and uric acid with outcome. This suggests microvascular neutrophil involvement mirroring endothelial dysfunction, a central component of the HFpEF syndrome and a potential treatment target.

Myeloperoxidase is a promising therapeutic target for treatment of patients suffering from heart failure with preserved ejection fraction (HFpEF). We aimed to discover a covalent myeloperoxidase inhibitor with high selectivity for myeloperoxidase over thyroid peroxidase, limited penetration of the blood–brain barrier, and pharmacokinetics suitable for once-daily oral administration at low dose. Structure–activity relationship, biophysical, and structural studies led to prioritization of four compounds for in-depth safety and pharmacokinetic studies in animal models. One compound (AZD4831) progressed to clinical studies on grounds of high potency (IC 50 , 1.5 nM in vitro ) and selectivity (>450-fold vs thyroid peroxidase in vitro ), the mechanism of irreversible inhibition, and the safety profile. Following phase 1 studies in healthy volunteers and a phase 2a study in patients with HFpEF, a phase 2 b /3 efficacy study of AZD4831 in patients with HFpEF started in 2021.