Aims
Arginine vasopressin (AVP) mediates deleterious effects via vascular V1a and renal V2 receptors in heart failure (HF). Despite positive short‐term decongestive effects in phase II HF studies, selective V2 receptor antagonism has shown no long‐term mortality benefit, potentially related to unopposed V1a receptor activation. We compared the novel dual V1a/V2 receptor antagonist pecavaptan with the selective V2 receptor antagonist tolvaptan in pre‐clinical HF models.
Methods and results
In vitro IC50 determination in recombinant cell lines revealed similar receptor selectivity profiles (V2:V1a) of tolvaptan and pecavaptan for human and dog AVP receptors, respectively. Two canine models were used to compare haemodynamic and aquaretic effects: (i) anaesthetised dogs with tachypacing‐induced HF, and (ii) conscious telemetric dogs with a non‐invasive cardiac output (CO) monitor. Tolvaptan and pecavaptan exhibited no differences in urinary output. In HF dogs, pecavaptan counteracted the AVP‐induced increase in afterload and decrease in CO (pecavaptan: 1.83 ± 0.31 L/min; vs. tolvaptan: 1.46 ± 0.07 L/min, P < 0.05). In conscious telemetric animals, pecavaptan led to a significant increase in CO (+0.26 ± 0.17 L/min, P = 0.0086 vs. placebo), in cardiac index (+0.58 ± 0.39 L/min/m2, P = 0.009 vs. placebo) and a significant decrease in total peripheral resistance (−5348.6 ± 3601.3 dyn × s/cm5, P < 0.0001 vs. placebo), whereas tolvaptan was without any significant effect.
Conclusions
Simultaneous blockade of vascular V1a and renal V2 receptors efficiently induces aquaresis and counteracts AVP‐mediated haemodynamic aggravation in HF models. Dual V1a/V2 antagonism may lead to improved outcomes in HF.
Low androgen levels are associated with an increased risk of coronary artery disease (CAD), thrombosis and myocardial infarction (MI), suggesting that androgen has a protective role. However, little is known about the underlying molecular mechanism. Our genome-wide association study identified the ADTRP gene encoding the androgen-dependent TFPI regulating protein as a susceptibility gene for CAD and MI. The expression level of ADTRP was regulated by androgen, but the molecular mechanism is unknown. In this study, we identified the molecular mechanism by which androgen regulates ADTRP expression and tested the hypothesis that androgen plays a protective role in cardiovascular disease by activating ADTRP expression. Luciferase assays with an ADTRP promoter luciferase reporter revealed that androgen regulated ADTRP transcription in a dose- and time-dependent manner, and the effect was abolished by three different androgen inhibitors, including pyrvinium pamoate, bicalutamide, and cyproterone acetate. Chromatin-immunoprecipitation showed that the androgen receptor bound to a half androgen response element (ARE, TGTTCT) located at + 324 bp from the ADTRP transcription start site. The ARE is required for concentration-dependent transcriptional activation of ADTRP. HL-60 monocyte adhesion to EAhy926 endothelial cells (ECs) and transmigration across the EC layer, the two processes critical to development of CAD and MI, were inhibited by androgen, but the effect was rescued by ADTRP siRNA and exacerbated by overexpression of ADTRP and its downstream genes PIK3R3 and MIA3. These data suggest that one molecular mechanism by which androgen confers protection against CAD is stimulation of ADTRP expression.
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