title: Time-dependent regional myocardial denervation as a nonspecific response to transmyocardial laser revascularization.
abstract: BACKGROUND
  It is known that denervation occurs in the regions of myocardium treated by laser transmyocardial revascularization (TMR). The purpose of this study was to determine when regional denervation occurs in the early postoperative period and whether or not it is specific to laser TMR when compared with TMR using ultrasonically activated energy.
  
  
  METHODS
  Dogs with normal myocardium underwent either holmium:yttrium-aluminum-garnet laser TMR, TMR using an ultrasonic activated surgical blade, or a thoracotomy as sham operation. The responses of mean arterial pressure to topical application of bradykinin were examined at 3 time points: before, 1 hour after, and 2 weeks after surgery. The hearts were excised for Western blot and immunohistochemical analysis.
  
  
  RESULTS
  The response of mean arterial pressure to bradykinin was similarly attenuated in both TMR groups 1 hour after treatment and decreased to almost none after 2 weeks compared with pretreatment values. By comparison, the sham group showed persistent responses at both time points. Tissue tyrosine hydroxylase content of the treated area decreased significantly compared with the non-treated area in both TMR groups. Immunohistochemistry using anti-Protein Gene Product 9.5 and anti-synaptophysin antibodies showed a significant decrease in the number of positive nerve fibers in both TMR treatment groups compared with the sham group.
  
  
  CONCLUSIONS
  Transmyocardial revascularization caused partial alteration in myocardial innervation immediately after TMR. Tissue responses may continue to occur for the first 2 weeks after treatment. Tissue responses may also contribute to the development of denervation regardless of the energy source in non-ischemic canine myocardium.
authors.affiliation: Department of Cardiovascular Surgery, Okayama University Graduate School of Medicine and Dentistry, Okayama, Japan. ishino@tb3.so-net.ne.jp
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Asai
authors.forename: Shu
authors.initials: S
authors.lastname: Yamamoto
authors.forename: Kozo
authors.initials: K
authors.lastname: Ishino
authors.forename: Takushi
authors.initials: T
authors.lastname: Kohmoto
authors.forename: Mitsuhito
authors.initials: M
authors.lastname: Kuriyama
authors.forename: Gentaro
authors.initials: G
authors.lastname: Kato
authors.forename: Yu
authors.initials: Y
authors.lastname: Oshima
authors.forename: Noriyoshi
authors.initials: N
authors.lastname: Yamamoto
authors.forename: Kenji
authors.initials: K
authors.lastname: Notohara
authors.forename: Shigeru
authors.initials: S
authors.lastname: Okada
authors.forename: Shunji
authors.initials: S
authors.lastname: Sano
mesh_terms: D000818:Animals; D001794:Blood Pressure; D001920:Bradykinin / Q000008:administration & dosage; D003331:Coronary Vessels / Q000187:drug effects / Q000473:pathology / Q000503:physiopathology; D004195:Disease Models, Animal; D004285:Dogs; D004562:Electrocardiography; D006321:Heart / Q000294:innervation* / Q000503:physiopathology; D015151:Immunoblotting; D053685:Laser Therapy / Q000295:instrumentation / Q000379:methods*; D009121:Muscle Denervation; D009204:Myocardial Revascularization / Q000379:methods*; D009206:Myocardium / Q000201:enzymology / Q000276:immunology; D009389:Neovascularization, Pathologic; D012016:Reference Values; D013997:Time Factors; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism; D018084:Ultrasonography, Interventional / Q000295:instrumentation / Q000379:methods
chemical_list: D014446:Tyrosine 3-Monooxygenase; D001920:Bradykinin