Marc Humbert

Pulmonary Hypertension in Orphan Lung Diseases

Pulmonary hypertension (PH) may complicate the course of orphean lung diseases, and is classically associated with a decreased survival. Development of PH is usually related to chronic respiratory failure, but disproportionate pulmonary vascular involvement may occur in these diseases, particularly in the context of sarcoidosis, Langerhans’ cell histiocytosis, combined pulmonary fibrosis and emphysema syndrome, neurofibromatosis type 1 or lymphangioleiomyomatosis.

Hematopoietic Stem Cells and Chronic Hypoxia-Induced Pulmonary Vascular Remodelling

Alterations in structure and function of the lung vasculature is a common hallmark of chronic lung diseases with associated hypoxemia which, in turn, can lead to severe and progressive pulmonary hypertension (PH) and right heart failure. Key transcriptional regulators are known to coordinate the cellular response to oxygen deprivation (i.e., early growth response (Egr)-1 and hypoxia-inducible factor (HIF)-1α and HIF-2α), but some of them are also known as key masters involved in the quiescence and mobilization of hematopoietic stem cells (HSCs). Indeed, evidence for CXCL12 (also known as stromal-derived factor-1 [SDF-1]) induction in the pulmonary arterial wall following exposure of mice to chronic hypoxia has been reported. In this review, we will discuss the role of oxygen homeostasis on HSC function and on pulmonary vascular remodelling, focusing on whether a link could exist between these two physiopathological phenomena.

Le test de marche de 6 min dans l’HTAP associée à la sclérodermie systémique et dans l’HTAP idiopathique : corrélation avec les données hémodynamiques

Service de Pneumologie et Réanimation Respiratoire, Centre National de Référence de l’Hypertension Artérielle Pulmonaire, Hôpital Antoine-Béclère, Assistance publique-Hôpitaux de Paris, université Paris Sud-11, 92141 Clamart cedex, France ; Service de Médecine Interne, Centre National de Référence de la Sclérodermie, Hôpital Claude-Huriez, Université Lille 2; CHRU Lille; 1, Place de Verdun, 59037 Lille Cedex, France