Antiarrhythmic effects of the CNP analogue vosoritide via the PDE2 mediated cGMP/cAMP Crosstalk in diabetic cardiomyopathy

Background: Due to the worldwide increasing prevalence of obesity, the number of patients with diabetes mellitus is rising. In patients with diabetes mellitus, life-threatening arrhythmias and sudden cardiac death contribute to increased mortality as a result of diabetic cardiomyopathy. Proarrhythmic remodeling in the heart arise from metabolic stress and the chronic activation of the cardiac β-adrenergic-cAMP system, leading to dysregulated Ca²⁺ homeostasis. As the only isoform of phosphodiesterases, PDE2 can be stimulated by cGMP enhancing the hydrolysis of cAMP. Natriuretic peptides induce cGMP generation in cardiomyocytes (CM) and could thereby contribute to the reduction of arrhythmias and sudden cardiac death in diabetes, thus improving the prognosis. Therefore, the CNP analogue vosoritide, which is approved for the treatment of achondroplasia, might mediate this cGMP/cAMP crosstalk to reduce arrhythmia.

Purpose: Here, we aim to study whether the CNP analogue vosoritide has an antiarrhythmic effect through cGMP-dependent activation of PDE2.

Methods: Mice with CM-specific knockout of PDE2 (KO) were used in comparison to control (WT) mice. The mice, aged 8-11 weeks, were treated with 50 mg/kg i.p. streptozotocin (STZ) for 5 consecutive days to induce artificial diabetes mellitus. Echocardiograms were performed before and 5 weeks after the start of the STZ treatment, where all experiments were conducted. Ventricular cardiomyocytes were isolated using Langendorff perfusion. The measurement of intracellular Ca²⁺ transients and the number of spontaneous arrhythmic Ca²⁺ waves and sparks were carried out using calcium imaging technique. Additionally, intracellular L-type calcium currents were measured using patch-clamp technique. Furthermore, cAMP concentration was measured using cAMP ELISA. ECGs were recorded in ex-vivo perfused hearts to quantify arrhythmic events after ischemia-reperfusion injury (I/R).

Results: Compared to healthy controls, diabetic animals showed impaired systolic function with a ~9% reduction in ejection fraction. The significant increase in E/E’ ratio by ~34% indicated a diastolic dysfunction. Interestingly, the cardiac function was further worsened in diabetic PDE2 KO. On cellular level, vosoritide significantly reduced isoprenaline (ISO)-induced cAMP levels in diabetic CM. The effect was prevented by specific PDE2 inhibition with BAY 60-7550. Additionally, vosoritide was able to reduce the ISO-induced increased L-type Ca²⁺ current, whereas BAY or genetic PDE2 deletion counteracted this effect. Simultaneously, vosoritide significantly decreased the number of ISO-triggered Ca²⁺ waves as well as Ca2+ spark frequency. PDE2 inhibition by BAY or PDE2 KO prevented this antiarrhythmic effect. After I/R, vosoritide markedly decreased arrhythmia generation in ex-vivo perfused hearts, which was prohibited by BAY.

Conclusion: Vosoritide clearly reduced pro-arrhythmic signals after β-adrenergic stimulation and could potentially be repurposed as an antiarrhythmic treatment for diabetic cardiomyopathy.