The eye drop preservative benzalkonium chloride potently induces mitochondrial dysfunction and preferentially affects LHON mutant cells

Sandipan Datta, Christophe Baudouin, Francoise Brignole-Baudouin, Alexandre Denoyer, Gino A Cortopassi

Research output: Contribution to journalArticle

26 Scopus citations

Abstract

PURPOSE. Benzalkonium chloride (BAK) is the most commonly used eye drop preservative. Benzalkonium chloride has been associated with toxic effects such as ‘‘dry eye’’ and trabecular meshwork degeneration, but the underlying biochemical mechanism of ocular toxicity by BAK is unclear. In this study, we propose a mechanistic basis for BAK’s adverse effects. METHOD. Mitochondrial O2 consumption rates of human corneal epithelial primary cells (HCEP), osteosarcoma cybrid cells carrying healthy (control) or Leber hereditary optic neuropathy (LHON) mutant mtDNA [11778(G>A)], were measured before and after acute treatment with BAK. Mitochondrial adenosine triphosphate (ATP) synthesis and cell viability were also measured in the BAK-treated control: LHON mutant and human-derived trabecular meshwork cells (HTM3). RESULTS. Benzalkonium chloride inhibited mitochondrial ATP (IC50, 5.3 lM) and O2 consumption (IC50,10.9lM) in a concentration-dependent manner, by directly targeting mitochondrial complex I. At its pharmaceutical concentrations (107–667 lM), BAK inhibited mitochondrial function >90%. In addition, BAK elicited concentration-dependent cytotoxicity to cybrid cells (IC50,22.8lM) and induced apoptosis in HTM3 cells at similar concentrations. Furthermore, we show that BAK directly inhibits mitochondrial O consumption in HCEP cells (IC50,3.8lM) at 50-fold lower concentrations than used in eye2 drops, and that cells bearing mitochondrial blindness (LHON) mutations are further sensitized to BAK’s mitotoxic effect. CONCLUSIONS. Benzalkonium chloride inhibits mitochondria of human corneal epithelial cells and cells bearing LHON mutations at pharmacologically relevant concentrations, and we suggest this is the basis of BAK’s ocular toxicity. Prescribing BAK-containing eye drops should be avoided in patients with mitochondrial deficiency, including LHON patients, LHON carriers, and possibly primary open-angle glaucoma patients.

Original languageEnglish (US)
Pages (from-to)2406-2412
Number of pages7
JournalInvestigative Ophthalmology and Visual Science
Volume58
Issue number4
DOIs
StatePublished - Apr 1 2017

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Keywords

  • Benzalkonium chloride
  • Glaucoma
  • LHON
  • Mitochondrial complex I
  • Preservative

ASJC Scopus subject areas

  • Ophthalmology
  • Sensory Systems
  • Cellular and Molecular Neuroscience

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