title: Intrapulmonary aquaporin-5 expression as a possible biomarker for discriminating smothering and choking from sudden cardiac death: a pilot study.
abstract: The diagnosis of mechanical asphyxia as a cause of death, especially smothering and choking lacking evident injury, is one of the most difficult tasks in forensic pathology. The present study investigated the intrapulmonary expressions of aquaporins (AQPs; AQP-1 and AQP-5), as markers of water homeostasis, in forensic autopsy cases (total n=64, within 48 h postmortem) of mechanical asphyxiation due to neck compression (strangulation, n=24), including manual/ligature strangulation (n=12) and atypical hanging (n=12), smothering (n=7) and choking (n=8), compared with sudden cardiac death (n=14) and acute brain injury (n=11). Quantification of mRNA using a Taqman real-time PCR assay system demonstrated suppressed expression of AQP-5, but not AQP-1, in smothering and choking, compared with that in strangulation as well as sudden cardiac death and acute brain injury death. Immunostaining of AQP-5 was weakly detected in a linear pattern in the type I alveolar epithelial cells in smothering and choking cases, while cardiac and brain injury death showed marked positivity, and most strangulation cases had AQP-5-positive granular aggregates and fragments in intra-alveolar spaces. These observations indicate a partial difference in pulmonary molecular pathology among these causes of death, suggesting a procedure for possible discrimination of smothering and choking from sudden cardiac death.
authors.affiliation: Department of Legal Medicine, Osaka City University Medical School, Osaka, Japan. m2041106@med.osaka-cu.ac.jp
authors.forename: Qi
authors.initials: Q
authors.lastname: Wang
authors.forename: Takaki
authors.initials: T
authors.lastname: Ishikawa
authors.forename: Tomomi
authors.initials: T
authors.lastname: Michiue
authors.forename: Bao-Li
authors.initials: BL
authors.lastname: Zhu
authors.forename: Da-Wei
authors.initials: DW
authors.lastname: Guan
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Maeda
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000402:Airway Obstruction / Q000175:diagnosis*; D051398:Aquaporin 1 / Q000235:genetics / Q000378:metabolism; D051402:Aquaporin 5 / Q000235:genetics / Q000378:metabolism*; D001237:Asphyxia / Q000175:diagnosis*; D015415:Biomarkers / Q000378:metabolism; D001930:Brain Injuries / Q000378:metabolism; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D016757:Death, Sudden, Cardiac; D042783:Endothelial Cells / Q000378:metabolism; D004847:Epithelial Cells / Q000378:metabolism; D005260:Female; D049429:Forensic Pathology; D006801:Humans; D007150:Immunohistochemistry; D007223:Infant; D008168:Lung / Q000166:cytology / Q000378:metabolism*; D008264:Macrophages / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D019838:Neck Injuries / Q000175:diagnosis; D010865:Pilot Projects; D012333:RNA, Messenger / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D055815:Young Adult
chemical_list: D051402:Aquaporin 5; D015415:Biomarkers; D012333:RNA, Messenger; D051398:Aquaporin 1