Changes in mitochondrial bioenergetics have been proposed to be critical for triggering and effecting anesthetic-induced preconditioning (APC) against cardiac ischemia and reperfusion injury. The objective of this study was to analyze changes in mitochondrial protein levels, and link those changes to potential functional changes. A (18)O labeling method was applied for relative comparison of cardiac mitochondrial samples from control and isoflurane exposed rats before and after ischemia and reperfusion. Wistar rats were exposed to isoflurane for 30 min (APC) or did not receive the anesthetic (control). Rats were subjected to 30 min coronary occlusion and 15 min reperfusion without (ischemia) or after APC (ischemia + APC). The following comparisons were made: control vs. APC, control vs. ischemia, and APC vs. ischemia + APC. Proteins were analyzed by liquid chromatography-mass spectrometry. A total of 98 proteins currently annotated as mitochondrial proteins in the UniProt database were positively identified from three replicate experiments. Most of the changes during APC and ischemia occur in complexes of the electron transport chain. Overall, fewer changes in ETC complexes were found when comparing APC with APC+ischemia, than when comparing control and ischemia. This corresponds to the preservation of bioenergetics due to APC after ischemia and reperfusion as indicated by preserved ATP level and generation. Thus, a proteomic mass spectral approach does not only assess quantitative changes without prior knowledge of proteins, but also allows insight into the mechanisms of ischemia and reperfusion injury and APC.
"We hope the information summarized here will provide helpful insights into the potential of synergistic effects of VA at multiple sites in mitochondria that underlie their cardioprotective effects. MOLECULAR BINDING SITES FOR VA X-ray crystallography, molecular modeling, and structure– function studies indicate that anesthetics bind in hydrophobic cavities formed within proteins (Bertaccini et al., 2007). The lipophilic (or hydrophobic) nature of these binding sites underlies the Meyer–Overton correlation between anesthetic lipophilicity and potency (Hemmings, 2010). "
[Show abstract][Hide abstract] ABSTRACT: Mitochondria are critical modulators of cell function and are increasingly recognized as proximal sensors and effectors that ultimately determine the balance between cell survival and cell death. Volatile anesthetics (VA) are long known for their cardioprotective effects, as demonstrated by improved mitochondrial and cellular functions, and by reduced necrotic and apoptotic cell death during cardiac ischemia and reperfusion (IR) injury. The molecular mechanisms by which VA impart cardioprotection are still poorly understood. Because of the emerging role of mitochondria as therapeutic targets in diseases, including ischemic heart disease, it is important to know if VA-induced cytoprotective mechanisms are mediated at the mitochondrial level. In recent years, considerable evidence points to direct effects of VA on mitochondrial channel/transporter protein functions and electron transport chain (ETC) complexes as potential targets in mediating cardioprotection. This review furnishes an integrated overview of targets that VA impart on mitochondrial channels/transporters and ETC proteins that could provide a basis for cation regulation and homeostasis, mitochondrial bioenergetics, and reactive oxygen species (ROS) emission in redox signaling for cardiac cell protection during IR injury.
Frontiers in Physiology 09/2014; 5:341. DOI:10.3389/fphys.2014.00341 · 3.53 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The pharmacological conditioning of the heart with anaesthetics such as volatile anaesthetics or opioids is a phenomenon whereby a transient exposure to an anaesthetic agent protects the heart from the harmful consequences of myocardial ischemia and reperfusion injury. The cellular and molecular mechanisms of anaesthetic conditioning appear largely to mimic those of ischemic pre- and postconditioning. Progress has been made on the understanding of the underlying mechanisms although the order of events and the specific targets of anaesthetics that trigger protection are not always clear. In the laboratory the protection afforded by certain anaesthetics against cardiac ischemia and reperfusion injury is powerful and reproducible but this has not necessarily translated into similarly robust clinical benefits. Indeed, clinical studies and meta-analyses delivered variable results when comparing in the laboratory setting protective and non-protective anaesthetics. Reasons for this include underlying conditions such as age, obesity and diabetes. Animal models for disease or aging, human cardiomyocytes derived from stem cells of patients and further clinical studies are employed to better understand the underlying causes that prevent a more robust protection in patients.
British Journal of Pharmacology 10/2014; 172(8). DOI:10.1111/bph.12981 · 4.84 Impact Factor
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