RESUMEN
Background Cilostazol is a type 3 phosphodiesterase inhibitor which has been previously demonstrated to prevent the occurrence of tachyarrhythmia and improve defibrillation efficacy. However, the mechanism for this beneficial effect is still unclear. Since cardiac mito-chondria have been shown to play a crucial role in fatal cardiac arrhythmias and that oxidative stress is one of the main contributors to arr-hythmia generation, we tested the effects of cilostazol on cardiac mitochondria under severe oxidative stress. Methods Mitochondria were isolated from rat hearts and treated with H2O2 to induce oxidative stress. Cilostazol, at various concentrations, was used to study its protective effects. Pharmacological interventions, including a mitochondrial permeability transition pore (mPTP) blocker, cyclosporine A (CsA), and an inner membrane anion channel (IMAC) blocker, 4’-chlorodiazepam (CDP), were used to investigate the mechanistic role of cilostazol on cardiac mitochondria. Cardiac mitochondrial reactive oxygen species (ROS) production, mitochondrial membrane potential change and mi-tochondrial swelling were determined as indicators of cardiac mitochondrial function. Results Cilostazol preserved cardiac mitochondrial function when exposed to oxidative stress by preventing mitochondrial depolarization, mitochondrial swelling, and decreasing ROS produc-tion. Conclusions Our findings suggest that cardioprotective effects of cilostazol reported previously could be due to its prevention of car-diac mitochondrial dysfunction caused by severe oxidative stress.
RESUMEN
AIM To examine the effect of cilostazol, a no vel selective phosphodiesterase type 3 inhibitor, on adherence between neutrophils and human umbilical e ndothelial cells ( HUVECs ) and investigate its possible mechanisms. MET HODS Confluent HUVECs between 4～6 passages were used and stimulated by l ipopolysaccharide (LPS, 5 mg?L -1 ) with or without coincubation of cilosta zol (1～10 ?mol?L -1 ) for 24 h. Soluble cell adhesion molecules (sCAMs), including vascular cell adhesion molecule-1 (sVCAM-1), intercellular adhesion molecule-1 (sICAM-1) and endothelial leukocyte adhesion molecule-1 (sELAM-1, sE-selectin) in cell culture medium were measured by ELISA. RESULTS Cilostazol (1～10 ?mol?L -1 ) inhibited adherence between neutrophils and HUVECs in a dose- dependent manor. At the same time, cilostazol didn't affect sICAM-1 and sE-sel ectin release from LPS-stimulated HUVECs, but in contrast, it significantly inh ibited sVCAM-1 production under the same experiment condition, and this effect was canceled by H-89, an inhibitor of protein kinase A ( PKA ). CONCLUS ION Cilostazol significantly inhibits adherence between neutrophils and H UVECs, and downregulates sVCAM-1 release from LPS-activated HUVECs, and these effects on cytokine-challenged endothelial cells might be via a PKA-dependent pathway. The present result suggests that cilostazol partially eliminates some o f the adherent reactions of HUVECs to LPS, a deleterious cytokine, and it is rea sonable to consider that cilostazol might be a strategy for preventing atheroscl erosis and other cardiovascular diseases.