• Binu Tharakan, Juliet G Holder-Haynes, Felicia A Hunter, and Ed W Childs.
• Department of Surgery, Texas A&M University Health Science Center College of Medicine, Scott & White Memorial Hospital, 2401 South 31st St., Temple, TX 76508, USA.
• Am. J. Surg. 2008 Feb 1;195(2):174-8.

BackgroundThis study examined whether alpha lipoic acid (ALA), an antioxidant with anti-apoptotic properties, synthesized in mitochondria of endothelial cells, would inhibit intrinsic apoptotic signaling and microvascular endothelial cell hyperpermeability.MethodsRat lung microvascular endothelial cells were transfected with BAK (BH3) peptide (5 microg/mL) or active caspase-3 (5 microg/mL) and were pretreated with ALA (10 and 100 micromol/L). Hyperpermeability was determined using fluorescein isothiocyanate albumin-flux across the cells grown as monolayer. Reactive oxygen species (ROS) formation was determined using 123 dihydrorhodamine and mitochondrial membrane potential using JC-1. Cytochrome c levels and caspase-3 activity were determined using an enzyme-linked immunosorbent assay and a fluorometric assay, respectively.ResultsALA (100 micromol/L) pretreatment attenuated BAK (BH3)-induced hyperpermeability and ROS formation. ALA restored BAK (BH3)-induced collapse in mitochondrial membrane potential and decreased BAK (BH3)-induced cytochrome c release and caspase-3 activity.ConclusionsThese findings suggest that ALA attenuates BAK-induced monolayer hyperpermeability through the inhibition of ROS formation and intrinsic apoptotic signaling.

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