Helen A Christou

Learn More
Heme oxygenase (HO) catalyzes the oxidation of heme to generate carbon monoxide (CO) and bilirubin. CO increases cellular levels of cGMP, which regulates vascular tone and smooth muscle development. Bilirubin is a potent antioxidant. Hypoxia increases expression of the inducible HO isoform (HO-1) but not the constitutive isoform (HO-2). To determine whether(More)
The insulin-like growth factor (IGF) system is the dominant endocrine regulator of fetal growth, whereas insulin has a permissive role. Although a role for leptin in fetal growth has been suggested recently, the mechanism by which leptin may be related to fetal growth is not known; but leptin may interact with the IGF system in utero as it does in the(More)
OBJECTIVE We previously reported improved oxygenation, but no change, in rates of extracorporeal membrane oxygenation (ECMO) use or death among infants with persistent pulmonary hypertension of the newborn who received inhaled nitric oxide (NO) with conventional ventilation, irrespective of lung disease. The goal of our study was to determine whether(More)
Vascular endothelial growth factor (VEGF) is a potent mitogenic and permeability factor targeting predominantly endothelial cells. At least two tyrosine kinase receptors, Flk-1 and Flt-1, mediate its action and are mostly expressed by endothelial cells. VEGF and VEGF receptor expression are upregulated by hypoxia in vivo and the role of VEGF in(More)
Chronic hypoxia causes pulmonary hypertension with smooth muscle cell proliferation and matrix deposition in the wall of the pulmonary arterioles. We demonstrate here that hypoxia also induces a pronounced inflammation in the lung before the structural changes of the vessel wall. The proinflammatory action of hypoxia is mediated by the induction of distinct(More)
We investigated the role of heme oxygenase (HO)-1 in the development of hypoxia-induced pulmonary hypertension. HO catalyzes the breakdown of heme to the antioxidant bilirubin and the vasodilator carbon monoxide. Hypoxia is a potent but transient inducer of HO-1 in vascular smooth muscle cells in vitro and in the lung in vivo. By using agonists of HO-1, we(More)
Pulmonary hypertension (PH) is a life-threatening disease with unclear vascular mechanisms. We tested whether PH involves abnormal pulmonary vasoconstriction and impaired vasodilation. Male Sprague-Dawley rats were exposed to hypoxia (9% O(2)) for 2 weeks or injected with single dose of monocrotaline (MCT, 60 mg/kg s.c.). Control rats were normoxic or(More)
Extracellular acidosis (EA) has profound effects on vascular homeostasis, including vascular bed-specific alterations in vascular tone. Regulation of gene expression by EA has been observed in a variety of cells including vascular endothelial cells. Whether EA regulates gene expression in vascular smooth muscle cells (VSMCs) is not known. Heme oxygenase(More)
PURPOSE To evaluate whether there were differences in acquisition of research grant support between male and female faculty at eight Harvard Medical School-affiliated institutions. METHODS Data were obtained from the participating institutions on all research grant applications submitted by full-time faculty from 2001 through 2003. Data were analyzed by(More)
INTRODUCTION Cell-free plasma hemoglobin is associated with poor outcome in patients with sepsis. Extracellular hemoglobin and secondarily released heme amplify inflammation in the presence of microbial TLR ligands and/or endogenous mediators. Hemopexin, a plasma protein that binds heme with extraordinary affinity, blocks these effects and has been proposed(More)