Endothelin-1: possible implications in pulmonary vascular disease

A novel DLL4 mutation in Adams-Oliver syndrome with absence of the right pulmonary artery in newborn

Adams-Oliver syndrome (AOS), a rare inherited disorder, is characterized by scalp and terminal limb defects. Several genes associated with Notch pathway mutations have led to AOS. Here, we report a Thai male newborn presenting with aplasia cutis congenita and absence of a right pulmonary artery, which is suggestive of AOS. This was confirmed by the identification of a novel missense mutation in DLL4, a heterozygous one base pair change at nucleotide 82 (c.82G>C, p.Gly28Arg), which is in N-terminal domain. This is the first DLL4-related AOS case with arterial defect.

Plasma C-terminal proEndothelin-1 (CTproET-1) is affected by age, renal function, left atrial size and diastolic blood pressure in healthy subjects

Endothelin-1 (ET-1) is a short chained peptide primarily of endothelial origin. Concentrations of this peptide are increased in subjects with hypertension, primary pulmonary hypertension and myocardial infarction, however its short half-life makes quantification difficult. The C-terminal of proET-1 (CTproET-1) is stoichiometrically secreted with its bioactive peptide and would be a valid method of measuring the active peptide as it has a stable half-life and is less resistant to proteolytic cleavage. The objective of this study was to understand the factors (clinical, echocardiographic and biochemical) that specifically influence plasma CTproET-1 in healthy subjects. 518 healthy volunteers were recruited from a screening study. Plasma CTproET-1 concentrations were quantified using a novel immunoluminometric sandwich assay. In multivariate analyses, age (P<0.001), diastolic BP (P=0.007), LA size (P=0.001) and eGFR (P<0.001) were independently predictive of plasma CTproET-1 levels in the healthy subjects. Therefore the interpretation of plasma CTproET-1 levels in such individuals should take into account these variables to avoid potential confounding.

Current management of patients with pulmonary hypertension and right ventricular insufficiency

Pulmonary hypertension is a pathologic condition characterized by elevated pulmonary artery pressures and an associated vasculopathy. Primary pulmonary hypertension (PPH) is a rare condition with a sporadic occurrence and a familial form of the disorder. Abnormal vasomotor tone in the pulmonary vasculature results from an imbalance of the action of various vasoconstrictors/ vascular proliferative agents (endothelin and thromboxane) versus vasodilators /anti-proliferative agents (prostacyclin and nitric oxide). The mainstay of outpatient therapy has been the use of digitalis, diuretics, oxygen, and coumadin and the judicious use of vasodilator therapy. Calcium channel blockers in a select group and intravenous prostacyclin have dramatically improved survival for those with primary pulmonary hypertension. Use of prostaglandin I2 (PGI2) in other forms of chronic pulmonary arterial hypertension is not as clear, although evidence of initial beneficial response is promising. Importantly, over the next few years both pharmacologic and nonpharmacologic treatment modalities for pulmonary hypertension may rapidly change as we focus more on the abnormal pulmonary vascular biology and concomitant hemodynamic and neurohormonal milieu.

Vascular abnormalities in Adams-Oliver syndrome: cause or effect?

We describe a young girl diagnosed with the Adams-Oliver syndrome (AOS) associated with double outlet right ventricle, portal hypertension, and pulmonary hypertension. We hypothesize that a congenital vascular abnormality is the underlying pathogenesis and that the cutaneous defects characteristically seen in AOS represent the most common manifestation of this. We suggest that AOS should not merely be considered a syndrome consisting of aplasia cutis congenita and terminal transverse limb defects but rather a constellation of clinical findings resulting from an early embryonic vascular abnormality.