Dr Carolyn Lam: Welcome to Circulation on the Run, your weekly podcast summary and backstage pass to the journal and its editors. I'm Dr Carolyn Lam, associate editor from the National Heart Center in Duke National University of Singapore. Dr Greg Hundley: I'm Greg Hundley, associated editor from the VCU Pauley Heart Center in Richmond, Virginia. Dr Carolyn Lam: Greg, today's speaker paper is really special on a number of levels. First, it's a research letter and secondly, it's actually basic science. Now, this tells you it's got to be really special. Well, I'll just give you a hint. It talks about a new therapy for stroke. I'm going to leave it at that, leave you guessing because you've got to hang on as we tell you about the rest of the issue and then listen to the feature discussion. Now, the first original paper here, I want to describe as a basic paper focusing on PDE4B in heart failure. Dr Greg Hundley: All right, Carolyn, I'm not even going to let you start to quiz me on this. Can you tell me what in the world is PDE4B? Dr Carolyn Lam: All right. Phosphodiesterases, or PDEs, really represent a highly diverse super family of enzymes among which PDE3 and PDE4 are the main phosphodiesterases that degrading cyclic AMP with a high affinity in the heart. The cyclic AMP hydrolyzing phosphodiesterase 4B, which is PDE4B, is the key negative regulator of cardiac beta-adrenergic receptor stimulation. PDE4B deficiency leads to abnormal calcium handling and PDE4B is decreased in pressure overload hypertrophy suggesting that increasing PDE4B in the heart may be beneficial in heart failure. These authors led by Dr Vandecasteele from Inserm tested this hypothesis in elegant experiments involving both human cardiac tissues and transgenic mouse lines. Dr Greg Hundley: Carolyn, that was just a wonderful explanation and I really learned about these phosphodiesterases. Now, tell me what did they find in their study? Dr Carolyn Lam: The cyclic AMP hydrolyzing enzyme, PDE4B, was decreased in human failing hearts. Cardiac over expression of PDE4B in mice, resulting in a 15-fold increase in cyclic AMP hydrolysis decreased cardiac contraction and protected against the cardiotoxic effects of chronic beta-adrenergic stimulation. Whereas transgenic mice with a 50-fold increase in cardiac cyclic AMP hydrolysis underwent maladaptive remodeling. Furthermore, cardiac PDE4B gene transfer with serotype nine adeno associated viruses resulted in a significantly lower increase in cardiac PDE4B and protected against chronic catecholamine stimulation and transaortic constriction without depressing basal cardiac function. These results overall suggest that a moderate increase in cardiac PDE4B is beneficial to counteract the detrimental effects of excessive sympathetic system activation in heart failure and increase in PDE4B in the human heart could be achieved by gene therapy with adeno associated viruses or by using recently developed small molecules with PDE4 activating properties. Dr Greg Hundley: Wow, Carolyn. Very interesting. I mean, perhaps this'll work its way into heart failure management. Well, my study, our first study to describe involves the comparative efficacy and safety of oral P2Y12 inhibitors and acute coronary syndromes. It's a meta-analysis of 52,816 patients from 12 randomized trials. It comes to us from Professor Eliano Navarese from Nicholas Copernicus University. All right, Carolyn, here's your quiz. Have you wondered which PGY inhibitor is optimal for reducing risk of adverse cardiovascular events? Dr Carolyn Lam: Oh, that's an easy one. Of course I've wondered, but you're going to tell us the results. Dr Greg Hundley: It's getting harder and harder to trip you up Carolyn. Very clever, okay. This study aims to evaluate current evidence comparing the efficacy and safety profile of prasugrel, ticagrelor and clopidogrel in acute coronary syndrome by meta-analysis of 12 randomized clinical trials. Again, involving those 52,816 patients wit