Project description:Pulmonary arterial hypertension (PAH) is a disorder of the pulmonary vasculature associated with elevated pulmonary vascular resistance. Despite recent advances in the treatment of PAH, with eight approved clinical therapies and additional therapies undergoing clinical trials, PAH remains a serious life-threatening condition. The lack of pulmonary vascular selectivity and associated systemic adverse effects of these therapies remain the main obstacles to successful treatment. Peptide-mediated drug delivery that specifically targets the vasculature of PAH lungs may offer a solution to the lack of drug selectivity. Herein, we show highly selective targeting of rat PAH lesions by a novel cyclic peptide, CARSKNKDC (CAR). Intravenous administration of CAR peptide resulted in intense accumulation of the peptide in monocrotaline-induced and SU5416/hypoxia-induced hypertensive lungs but not in healthy lungs or other organs of PAH rats. CAR homed to all layers of remodeled pulmonary arteries, ie, endothelium, neointima, medial smooth muscle, and adventitia, in the hypertensive lungs. CAR also homed to capillary vessels and accumulated in the interstitial space of the PAH lungs, manifesting its extravasation activity. These results demonstrated the remarkable ability of CAR to selectively target PAH lung vasculature and effectively penetrate and spread throughout the diseased lung tissue. These results suggest the clinical utility of CAR in the targeted delivery of therapeutic compounds and imaging probes to PAH lungs.
Project description:Pulmonary arterial hypertension (PAH) is a severe and progressive vascular disease characterized by pulmonary vascular remodeling, proliferation, and inflammation. Despite the availability of effective treatments, PAH may culminate in right ventricular failure and death. Currently approved medications act through three well-characterized pathways: the nitric oxide, endothelin, and prostacyclin pathways. Ongoing research efforts continue to expand our understanding of the molecular pathogenesis of this complex and multifactorial disease. Based on recent discoveries in the pathobiology of PAH, several new treatments are being developed and tested with the goal of modifying the disease process and ultimately improving the long-term prognosis.
Project description:Pulmonary arterial hypertension (PAH) is a devastating illness causing already significant morbidity in childhood. Currently approved treatment options for children comprise the endothelin receptor antagonist bosentan, as well as the phosphodiesterase-5 inhibitor sildenafil. But PAH treatment has advanced significantly over the past decade, and new classes of targeted drug therapies, such as stimulators of the soluble guanylate cyclase (riociguat) or prostacyclin receptor agonists (selexipag), are currently evaluated regarding their efficacy and safety in children, in order to limit off-label use. Due to the different etiologies in children, such as PAH-CHD, there is no evidence that initial combination therapy in children is superior to a mono-therapy with respect to survival. Special attention should also be paid to the pharmacology of PAH drugs in children, which might be impacted by ontogeny or drug-drug-interactions. Therapeutic drug monitoring may be useful in pediatric patients. There is a clear need for more controlled studies of PAH medications, alone or in combination therapy in the pediatric age group. Data from clinical trials as well as from patient registries should be pooled to optimize drug development and evaluation, trial design, and evidence-based pharmacotherapy in pediatric patients with PAH. In this review, the current treatment options of pediatric PAH are summarized, and an overview of new treatment concepts, which are already evaluated in adults, is presented.
Project description:Treatment options for pulmonary arterial hypertension (PAH) have considerably improved in the past few years. Endothelin (ET)-receptor antagonism has been established as a first-line option for the majority of PAH patients. Endothelin-receptor antagonists (ETRAs) comprise sulfonamide and non-sulfonamide agents with different affinities for ET-receptor subtypes (ET(A) and ET(B)), and the focus of development has shifted from drugs with less selectivity to those with high selectivity. There is ongoing debate as to whether selective or non-selective ET-receptor antagonism is more beneficial in the treatment of PAH. This paper reviews the current evidence from experimental and clinical studies obtained from a thorough literature search focusing on the three marketed drugs bosentan, sitaxentan, and ambrisentan. A clinically meaningful difference among the three approved ETRAs with respect to their ET-receptor selectivity could not be demonstrated to date. Therefore, in clinical practice, other features are likely to be of greater relevance when considering treatment, such as the potential for serious drug-drug interactions, convenience of dosing schedule, or rates of limiting side effects. These characteristics bear more relation to the chemical or pharmacological properties of the drugs than to receptor selectivity itself.
Project description:Macitentan is the most recently approved dual endothelin-receptor antagonist (ERA) for the treatment of symptomatic pulmonary arterial hypertension. Compared to other available ERAs, it demonstrates superior receptor-binding properties, with consequently improved tissue penetration, and a longer duration of action allowing for once-daily dosing. It has a favorable adverse-effect profile, with notably no demonstrable increase in the risk of hepatotoxicity or peripheral edema, but like other ERAs, it is potentially limited by significant anemia. Phase I data have demonstrated a favorable drug-drug interaction profile and no need for dose adjustment with hepatic and renal impairment. In the pivotal SERAPHIN study, treatment of symptomatic pulmonary arterial hypertension patients with macitentan led to statistically significant improvements in functional class, exercise tolerance, and hemodynamic parameters, in addition to a reduction in morbidity in an event-driven long-term trial.
Project description:Pulmonary arterial hypertension is a chronic and life-threatening disease that if left untreated is fatal. Current therapies include stimulating the nitric oxide-soluble guanylate cyclase (sGC)-cyclic guanosine monophosphate axis, improving the prostacyclin pathway and inhibiting the endothelin pathway. Phosphodiesterase type 5 inhibitors, such as sildenafil, and the sGC stimulator riociguat are currently used in the treatment of pulmonary arterial hypertension. This article discusses the similarities and differences between phosphodiesterase type 5 inhibitors and sGC stimulator based on pharmacological action and clinical trials, and considers which is better for the treatment of pulmonary arterial hypertension.