Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 2 de 2
Filtros adicionais

Intervalo de ano
Eur Heart J ; 2019 Apr 19.
Artigo em Inglês | MEDLINE | ID: mdl-31004144


AIMS: Heart failure with preserved ejection fraction (HFpEF) and pathological cardiac aging share a complex pathophysiology, including extracellular matrix remodelling (EMR). Protease-activated receptor 2 (PAR2) deficiency is associated with EMR. The roles of PAR1 and PAR2 have not been studied in HFpEF, age-dependent cardiac fibrosis, or diastolic dysfunction (DD). METHODS AND RESULTS: Evaluation of endomyocardial biopsies from patients with HFpEF (n = 14) revealed that a reduced cardiac PAR2 expression was associated with aggravated DD and increased myocardial fibrosis (r = -0.7336, P = 0.0028). In line, 1-year-old PAR2-knockout (PAR2ko) mice suffered from DD with preserved systolic function, associated with an increased age-dependent α-smooth muscle actin expression, collagen deposition (1.7-fold increase, P = 0.0003), lysyl oxidase activity, collagen cross-linking (2.2-fold increase, P = 0.0008), endothelial activation, and inflammation. In the absence of PAR2, the receptor-regulating protein caveolin-1 was down-regulated, contributing to an augmented profibrotic PAR1 and transforming growth factor beta (TGF-ß)-dependent signalling. This enhanced TGF-ß/PAR1 signalling caused N-proteinase (ADAMTS3) and C-proteinase (BMP1)-related increased collagen I production from cardiac fibroblasts (CFs). PAR2 overexpression in PAR2ko CFs reversed these effects. The treatment with the PAR1 antagonist, vorapaxar, reduced cardiac fibrosis by 44% (P = 0.03) and reduced inflammation in a metabolic disease model (apolipoprotein E-ko mice). Patients with HFpEF with upstream PAR inhibition via FXa inhibitors (n = 40) also exhibited reduced circulating markers of fibrosis and DD compared with patients treated with vitamin K antagonists (n = 20). CONCLUSIONS: Protease-activated receptor 2 is an important regulator of profibrotic PAR1 and TGF-ß signalling in the heart. Modulation of the FXa/FIIa-PAR1/PAR2/TGF-ß-axis might be a promising therapeutic approach to reduce HFpEF.

Pulm Circ ; 3(1): 252-66, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-23662203


Drug trials in neonates and children with pulmonary hypertensive vascular disease pose unique but not insurmountable challenges. Childhood is defined by growth and development. Both may influence disease and outcomes of drug trials. The developing pulmonary vascular bed and airways may be subjected to maldevelopment, maladaptation, growth arrest, or dysregulation that influence the disease phenotype. Drug therapy is influenced by developmental changes in renal and hepatic blood flow, as well as in metabolic systems such as cytochrome P450. Drugs may affect children differently from adults, with different clearance, therapeutic levels and toxicities. Toxicity may not be manifested until the child reaches physical, endocrine and neurodevelopmental maturity. Adverse effects may be revealed in the next generation, should the development of ova or spermatozoa be affected. Consideration of safe, age-appropriate tablets and liquid formulations is an obvious but often neglected prerequisite to any pediatric drug trial. In designing a clinical trial, precise phenotyping and genotyping of disease is required to ensure appropriate and accurate inclusion and exclusion criteria. We need to explore physiologically based pharmacokinetic modeling and simulations together with statistical techniques to reduce sample size requirements. Clinical endpoints such as exercise capacity, using traditional classifications and testing cannot be applied routinely to children. Many lack the necessary neurodevelopmental skills and equipment may not be appropriate for use in children. Selection of endpoints appropriate to encompass the developmental spectrum from neonate to adolescent is particularly challenging. One possible solution is the development of composite outcome scores that include age and a developmentally specific functional classification, growth and development scores, exercise data, biomarkers and hemodynamics with repeated evaluation throughout the period of growth and development. In addition, although potentially costly, we recommend long-term continuation of blinded dose ranging after completion of the short-term, double-blind, placebo-controlled trial for side-effect surveillance, which should include neurodevelopmental and peripubertal monitoring. The search for robust evidence to guide safe therapy of children and neonates with pulmonary hypertensive vascular disease is a crucial and necessary goal.