title: Cardiac preconditioning with local laser-induced hyperthermia.
abstract: BACKGROUND
  Whole body hyperthermia has been shown to be highly effective in preconditioning cardiac tissue against reperfusion injury. The current study was aimed to assess the ability of regional sublethal laser-induced hyperthermia to precondition cardiac tissue against ischemic-induced myocardial infarction.
  
  
  RESULTS
  Diode laser radiation was used to locally heat (42 degrees C) the left ventricle by irradiating the epicardial surface of rat heart for 20 min. As control, another group of animals were treated with whole-body hyperthermia (WBH) for 20 min. After a 4-h recovery period, the left coronary artery was occluded for 30 min followed by 4 h of reperfusion. A significant degree of reduction in infarct size as assessed by percent of at-risk area was observed in animals that were subjected to laser-induced local hyperthermia (15.4 +/- 3.1; n = 5) versus the sham group (49.8 +/- 6.6; n = 5). The degree of cardiac protection induced by local hyperthermia was similar to the protection observed when the animals were preconditioned with WBH. Furthermore, regional laser-induced hyperthermia and WBH induced similar degree of up-regulation of heat shock protein 70 in cardiac tissue. Regional hyperthermia up-regulated heat shock protein in regions of the heart beyond that directly subjected to laser-induced heat stress.
  
  
  CONCLUSIONS
  Sublethal local heating of the heart with diode laser irradiation can improve myocardial salvage and may provide a practical approach for tissue preconditioning against reperfusion injury.
authors.affiliation: Center of Biomedical Engineering, Department of Pathology, University of Texas Medical Branch, Galveston, Texas 77555-0456, USA.
authors.forename: Bin
authors.initials: B
authors.lastname: Gong
authors.forename: Brent
authors.initials: B
authors.lastname: Bell
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Boor
authors.forename: Thomas B
authors.initials: TB
authors.lastname: Albrecht
authors.forename: Gregory K
authors.initials: GK
authors.lastname: Asimakis
authors.forename: Massoud
authors.initials: M
authors.lastname: Motamedi
mesh_terms: D000818:Animals; D001831:Body Temperature; D018840:HSP70 Heat-Shock Proteins / Q000378:metabolism*; D006979:Hyperthermia, Induced / Q000379:methods*; D019157:Ischemic Preconditioning, Myocardial / Q000379:methods*; D054023:Lasers, Semiconductor; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D015854:Up-Regulation
chemical_list: D018840:HSP70 Heat-Shock Proteins