title: Human fetal inner ear involvement in congenital cytomegalovirus infection.
abstract: BACKGROUND
  Congenital cytomegalovirus (CMV) infection is a leading cause of sensorineural hearing loss (SNHL). The mechanisms of pathogenesis of CMV-related SNHL are still unclear. The aim is to study congenital CMV-related damage in the fetal inner ear, in order to better understand the underlying pathophysiology behind CMV-SNHL.
  
  
  RESULTS
  We studied inner ears and brains of 20 human fetuses, all at 21 week gestational age, with a high viral load in the amniotic fluid, with and without ultrasound (US) brain abnormalities. We evaluated histological brain damage, inner ear infection, local inflammatory response and tissue viral load.Immunohistochemistry revealed that CMV was positive in 14/20 brains (70%) and in the inner ears of 9/20 fetuses (45%). In the cases with inner ear infection, the marginal cell layer of the stria vascularis was always infected, followed by infection in the Reissner's membrane. The highest tissue viral load was observed in the inner ear with infected Organ of Corti. Vestibular labyrinth showed CMV infection of sensory cells in the utricle and in the crista ampullaris.US cerebral anomalies were detected in 6 cases, and in all those cases, the inner ear was always involved. In the other 14 cases with normal brain scan, histological brain damage was present in 8 fetuses and 3 of them presented inner ear infection.
  
  
  CONCLUSIONS
  CMV-infection of the marginal cell layer of the stria vascularis may alter potassium and ion circulation, dissipating the endocochlear potential with consequent SNHL. Although abnormal cerebral US is highly predictive of brain and inner ear damage, normal US findings cannot exclude them either.
authors.affiliation: Operative Unit of Clinical Microbiology, St, Orsola-Malpighi General Hospital, University of Bologna, Via Massarenti 9, 40138, Bologna, Italy. liliana.gabrielli@aosp.bo.it.
authors.forename: Liliana
authors.initials: L
authors.lastname: Gabrielli
authors.forename: Maria Paola
authors.initials: MP
authors.lastname: Bonasoni
authors.forename: Donatella
authors.initials: D
authors.lastname: Santini
authors.forename: Giulia
authors.initials: G
authors.lastname: Piccirilli
authors.forename: Angela
authors.initials: A
authors.lastname: Chiereghin
authors.forename: Brunella
authors.initials: B
authors.lastname: Guerra
authors.forename: Maria Paola
authors.initials: MP
authors.lastname: Landini
authors.forename: Maria Grazia
authors.initials: MG
authors.lastname: Capretti
authors.forename: Marcello
authors.initials: M
authors.lastname: Lanari
authors.forename: Tiziana
authors.initials: T
authors.lastname: Lazzarotto
mesh_terms: D000653:Amniotic Fluid / Q000821:virology; D001921:Brain / Q000196:embryology / Q000473:pathology / Q000503:physiopathology; D018414:CD8-Positive T-Lymphocytes; D003587:Cytomegalovirus / Q000302:isolation & purification*; D003586:Cytomegalovirus Infections / Q000151:congenital* / Q000473:pathology / Q000821:virology*; D007758:Ear, Inner / Q000196:embryology* / Q000473:pathology / Q000821:virology; D004453:Echoencephalography; D005315:Fetal Diseases / Q000276:immunology / Q000473:pathology / Q000821:virology*; D006801:Humans; D007150:Immunohistochemistry; D007762:Labyrinthitis / Q000276:immunology / Q000473:pathology / Q000821:virology*