title: Expression of components of the renin-angiotensin system in proliferating infantile haemangioma may account for the propranolol-induced accelerated involution.
abstract: Infantile haemangioma is a benign tumour of the microvasculature characterised by excessive proliferation of immature endothelial cells. It typically undergoes rapid proliferation during infancy followed by spontaneous slow involution during childhood often leaving a fibro-fatty residuum. In 2008, propranolol, a non-selective β-blocker, was serendipitously discovered to induce accelerated involution of a proliferating infantile haemangioma. However, the mechanism by which propranolol causes this dramatic effect is unclear. Using immunohistochemical staining, we show that the CD34+ endothelial progenitor cells of the microvessels in proliferating infantile haemangioma express angiotensin-converting enzyme and angiotensin II receptor-2, but not angiotensin II receptor-1. We have also shown using our in vitro explant model that the cells emanating from proliferating haemangioma biopsies form blast-like structures that proliferate in the presence of angiotensin II. We present here a plausible model involving the renin-angiotensin system that may account for the propranolol-induced accelerated involution of proliferating infantile haemangioma.
authors.affiliation: School of Biological Sciences, Victoria University of Wellington, and Department of Pathology, Hutt Hospital, Wellington, New Zealand.
authors.forename: Tinte
authors.initials: T
authors.lastname: Itinteang
authors.forename: Helen D
authors.initials: HD
authors.lastname: Brasch
authors.forename: Swee T
authors.initials: ST
authors.lastname: Tan
authors.forename: Darren J
authors.initials: DJ
authors.lastname: Day
mesh_terms: D000319:Adrenergic beta-Antagonists / Q000008:administration & dosage; D000809:Angiotensins / Q000096:biosynthesis*; D014408:Biomarkers, Tumor / Q000096:biosynthesis; D049109:Cell Proliferation / Q000187:drug effects; D018450:Disease Progression; D005153:Facial Neoplasms / Q000188:drug therapy / Q000378:metabolism* / Q000473:pathology; D005500:Follow-Up Studies; D006391:Hemangioma / Q000188:drug therapy / Q000378:metabolism* / Q000473:pathology; D006801:Humans; D007150:Immunohistochemistry; D007223:Infant; D018613:Microscopy, Confocal; D011379:Prognosis; D011433:Propranolol / Q000008:administration & dosage*; D012083:Renin / Q000096:biosynthesis*; D012084:Renin-Angiotensin System / Q000235:genetics*; D014407:Tumor Cells, Cultured
chemical_list: D000319:Adrenergic beta-Antagonists; D000809:Angiotensins; D014408:Biomarkers, Tumor; D011433:Propranolol; D012083:Renin