Abstracts from the 8th International Conference on cGMP Generators, Effectors and Therapeutic Implications

This work was supported by a restricted research grant of Bayer AG

Impact of the mitochondria-targeted antioxidant MitoQ on hypoxia-induced pulmonary hypertension.

Increased mitochondrial reactive oxygen species (ROS), particularly superoxide have been suggested to mediate hypoxic pulmonary vasoconstriction (HPV), chronic hypoxia-induced pulmonary hypertension (PH) and right ventricular (RV) remodelling.We determined ROS in acute, chronic hypoxia and investigated the effect of the mitochondria-targeted antioxidant MitoQ under these conditions.The effect of MitoQ or its inactive carrier substance, decyltriphenylphosphonium (TPP+), on acute HPV (1% O2 for 10 minutes) was investigated in isolated blood-free perfused mouse lungs. Mice exposed for 4 weeks to chronic hypoxia (10% O2) or after banding of the main pulmonary artery (PAB) were treated with MitoQ or TPP+ (50 mg/kg/day).Total cellular superoxide and mitochondrial ROS levels were increased in pulmonary artery smooth muscle cells (PASMC), but decreased in pulmonary fibroblasts in acute hypoxia. MitoQ significantly inhibited HPV and acute hypoxia-induced rise in superoxide concentration. ROS was decreased in PASMC, while it increased in the RV after chronic hypoxia. Correspondingly, MitoQ did not affect the development of chronic hypoxia-induced PH, but attenuated RV remodelling after chronic hypoxia as well as after PAB.Increased mitochondrial ROS of PASMC mediate acute HPV, but not chronic hypoxia-induced PH. MitoQ may be beneficial under conditions of exaggerated acute HPV

Hämodynamische Definition der pulmonalen Hypertonie: Kommentar zu der vorgeschlagenen Änderung durch das 6th World Symposium on Pulmonary Hypertension

The ESC/ERS guidelines (published at the end of 2015) and other international recommendations defined pulmonary hypertension (PH) by an invasively measured mean pulmonary arterial pressure (mPAP) >= 25mmHg at rest. At the 6th World Symposium on Pulmonary Hypertension in Nice a modification of this hemodynamic definition in the sense of lowering the threshold to >20mmHg was proposed. A pulmonary vascular resistance (PVR) >= 3 Wood units (WU) is additionally required for the diagnosis of pre-capillary PH. This modification must be critically reviewed with regard to the underlying rationale and possible consequences. Therefore, a detailed explanation is required. In particular, it must be made clear that this change currently has no influence on the evidence-based and approval-compliant prescription of drugs for the targeted therapy of pulmonary arterial hypertension (PAH)