title: Mechanisms of amiodarone and desethylamiodarone cytotoxicity in nontransformed human peripheral lung epithelial cells.
abstract: Amiodarone (AM) is a potent antidysrhythmic agent that can cause potentially life-threatening pulmonary fibrosis, and N-desethylamiodarone (DEA), an AM metabolite, may contribute to AM toxicity. Apoptotic cell death in nontransformed human peripheral lung epithelial 1A (HPL1A) cells was assessed by annexin V-fluorescein isothiocyanate (ann-V) staining and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL), and necrotic cell death was assessed by propidium iodide (PI) staining. The percentage of cells that were PI-positive increased more than six times with 20 μM AM and approximately doubled with 3.5 μM DEA, relative to control. The percentage of cells that were ann-V-positive decreased by more than 80% after 24-h exposure to 10 μM AM but more than doubled after 24-h incubation with 3.5 μM DEA. Incubation for 24 h with 5.0 μM DEA increased the percentage of cells that were TUNEL-positive more than six times. Incubation with AM (2.5 μM) or DEA (1-2 μM) for 24 h did not significantly alter angiotensinogen mRNA levels. Furthermore, angiotensin II (100 pM-1 μM) alone or in combination with AM or DEA did not alter cytotoxicity, and pretreatment with the angiotensin-converting enzyme inhibitor and antioxidant captopril (3-6 μM) did not protect against AM or DEA cytotoxicity. In conclusion, AM activates primarily necrotic pathways, whereas DEA activates both necrotic and apoptotic pathways, and the renin-angiotensin system does not seem to be involved in AM or DEA cytotoxicity in HPL1A cells.
authors.affiliation: Department of Pharmacology and Toxicology, Queen’s University, Kingston, Ontario, Canada.
authors.forename: Jeanne E
authors.initials: JE
authors.lastname: Mulder
authors.forename: James F
authors.initials: JF
authors.lastname: Brien
authors.forename: William J
authors.initials: WJ
authors.lastname: Racz
authors.forename: Takashi
authors.initials: T
authors.lastname: Takahashi
authors.forename: Thomas E
authors.initials: TE
authors.lastname: Massey
mesh_terms: D000638:Amiodarone / Q000031:analogs & derivatives* / Q000378:metabolism / Q000633:toxicity*; D000804:Angiotensin II / Q000633:toxicity; D000808:Angiotensinogen / Q000235:genetics; D000889:Anti-Arrhythmia Agents / Q000633:toxicity*; D017209:Apoptosis / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D004847:Epithelial Cells / Q000187:drug effects / Q000473:pathology; D006801:Humans; D020287:In Situ Nick-End Labeling; D008168:Lung / Q000187:drug effects* / Q000473:pathology; D009336:Necrosis; D012333:RNA, Messenger / Q000032:analysis
chemical_list: D000889:Anti-Arrhythmia Agents; D012333:RNA, Messenger; D000808:Angiotensinogen; D000804:Angiotensin II; C036116:desethylamiodarone; D000638:Amiodarone