Pulmonary circulation
-
Pulmonary circulation · Apr 2018
BMPR2 mutations and endothelial dysfunction in pulmonary arterial hypertension (2017 Grover Conference Series).
Despite the discovery more than 15 years ago that patients with hereditary pulmonary arterial hypertension (HPAH) inherit BMP type 2 receptor ( BMPR2) mutations, it is still unclear how these mutations cause disease. In part, this is attributable to the rarity of HPAH and difficulty obtaining tissue samples from patients with early disease. However, in addition, limitations to the approaches used to study the effects of BMPR2 mutations on the pulmonary vasculature have restricted our ability to determine how individual mutations give rise to progressive pulmonary vascular pathology in HPAH. ⋯ We discuss some of the controversies and challenges that have faced investigators exploring the role of BMPR2 mutations in HPAH, focusing specifically on the effects different BMPR2 mutation have on endothelial function, and whether there are qualitative differences between different BMPR2 mutations. We discuss evidence that BMPR2 signaling regulates a number of responses that may account for endothelial abnormalities in HPAH and summarize limitations of the models that are used to study these effects. Finally, we discuss evidence that BMPR2-dependent effects on endothelial metabolism provides a unifying explanation for the many of the BMPR2 mutation-dependent effects that have been described in patients with HPAH.
-
Pulmonary circulation · Apr 2018
Case ReportsAmelioration of right ventricular systolic function and stiffness in a patient with idiopathic pulmonary arterial hypertension treated with oral triple combination therapy.
Right ventricular (RV) function is an important determinant of the prognosis in patients with pulmonary arterial hypertension (PAH). In the context of recent therapeutic progress, there is an increasing need for better monitoring of RV function for management of PAH. We present the case of a 42-year-old woman with idiopathic PAH who was treated with three oral pulmonary vasodilators, i.e. tadalafil, ambrisentan, and beraprost. ⋯ In addition, we calculated three recently introduced indices of intrinsic RV function: end-systolic elastance (Ees; an index of RV contractility), Ees/arterial elastance ratio (Ees/Ea; an index of RV/pulmonary arterial coupling), and β (an index of RV stiffness) using cardiac magnetic resonance imaging and Swan-Ganz catheterization measurements. Notably, in contrast to conventional parameters, Ees, Ees/Ea, and β showed persistent improvement during the entire two-year follow-up. The application of Ees, Ees/Ea, and β may play an additional role in a comprehensive assessment of RV function in PAH.
-
Pulmonary circulation · Jan 2018
COPD as an endothelial disorder: endothelial injury linking lesions in the lungs and other organs? (2017 Grover Conference Series).
Chronic obstructive pulmonary disease (COPD) is characterized by chronic expiratory airflow obstruction that is not fully reversible. COPD patients develop varying degrees of emphysema, small and large airway disease, and various co-morbidities. It has not been clear whether these co-morbidities share common underlying pathogenic processes with the pulmonary lesions. ⋯ More recently, cigarette smoke-induced endothelial dysfunction/injury have been linked to the pulmonary lesions in COPD (especially emphysema) and systemic co-morbidities including atherosclerosis, pulmonary hypertension, and chronic renal injury. Herein, we review the evidence linking endothelial injury to COPD, and the pathways underlying endothelial injury and the "vascular COPD phenotype" including: (1) direct toxic effects of cigarette smoke on endothelial cells; (2) generation of auto-antibodies directed against endothelial cells; (3) vascular inflammation; (4) increased oxidative stress levels in vessels inducing increases in lipid peroxidation and increased activation of the receptor for advanced glycation end-products (RAGE); (5) reduced activation of the anti-oxidant pathways in endothelial cells; (6) increased endothelial cell release of mediators with vasoconstrictor, pro-inflammatory, and remodeling activities (endothelin-1) and reduced endothelial cell expression of mediators that promote vasodilation and homeostasis of endothelial cells (nitric oxide synthase and prostacyclin); and (7) increased endoplasmic reticular stress and the unfolded protein response in endothelial cells. We also review the literature on studies of drugs that inhibit RAGE signaling in other diseases (angiotensin-converting enzyme inhibitors and angiotensin receptor blockers), or vasodilators developed for idiopathic pulmonary arterial hypertension that have been tested on cell culture systems, animal models of COPD, and/or smokers and COPD patients.
-
Pulmonary circulation · Jan 2018
The impact of ambrisentan and tadalafil upfront combination therapy on cardiac function in scleroderma associated pulmonary arterial hypertension patients: cardiac magnetic resonance feature tracking study.
The aim of this study was to evaluate the effect of upfront combination therapy with ambrisentan and tadalafil on left ventricular (LV) and right ventricular (RV) function in patients with systemic sclerosis-associated pulmonary arterial hypertension (SSc-PAH). LV and RV peak longitudinal and circumferential strain and strain rate (SR), which consisted of peak systolic SR (SRs), peak early diastolic SR (SRe), and peak atrial-diastolic SR (SRa) were analyzed using cardiac magnetic resonance imaging (CMRI) data from the recently published ATPAHSS-O trial (ambrisentan and tadalafil upfront combination therapy in SSc-PAH). Twenty-one patients completed the study protocol. ⋯ Increased cardiac index was associated with improved LV pGLSRe, and reduction in mean right atrial pressure was correlated with improved RVFW pLS and pLSRa. Combination therapy was associated with a significant improvement in both RV and LV function as assessed by CMR-derived strain and SR. Importantly, the improvement in RV and LV strain and SR correlated with improvements in known prognostic markers of PAH. (Approved by clinicaltrials.gov [NCT01042158] before patient recruitment.).
-
Pulmonary circulation · Jul 2017
Pulmonary vascular effect of insulin in a rodent model of pulmonary arterial hypertension.
Pulmonary arterial hypertension (PAH) is associated with metabolic derangements including insulin resistance, although their effects on the cardiopulmonary disease are unclear. We hypothesized that insulin resistance promotes pulmonary hypertension (PH) development and mutations in type 2 bone morphogenetic protein receptor (BMPR2) cause cellular insulin resistance. Using a BMPR2 transgenic murine model of PAH and two models of inducible diabetes mellitus, we explored the impact of hyperglycemia and/or hyperinsulinemia on development and severity of PH. ⋯ Experimental hyperinsulinemia is strongly associated with PH in both control and BMPR2-mutant mice, though to a greater degree in those with BMPR2 mutation. Human pulmonary endothelial cells with BMPR2 mutation have evidence of reduced glucose uptake due to impaired glucose transporter translocation. These experiments support a role for hyperinsulinemia in pulmonary vascular disease.