title: Exercise training preserves ischemic preconditioning in aged rat hearts by restoring the myocardial polyamine pool.
abstract: BACKGROUND
  Ischemic preconditioning (IPC) strongly protects against myocardial ischemia reperfusion (IR) injury. However, IPC protection is ineffective in aged hearts. Exercise training reduces the incidence of age-related cardiovascular disease and upregulates the ornithine decarboxylase (ODC)/polyamine pathway. The aim of this study was to investigate whether exercise can reestablish IPC protection in aged hearts and whether IPC protection is linked to restoration of the cardiac polyamine pool.
  
  
  METHODS
  Rats aging 3 or 18 months perform treadmill exercises with or without gradient respectively for 6 weeks. Isolated hearts and isolated cardiomyocytes were exposed to an IR and IPC protocol.
  
  
  RESULTS
  IPC induced an increase in myocardial polyamines by regulating ODC and spermidine/spermine acetyltransferase (SSAT) in young rat hearts, but IPC did not affect polyamine metabolism in aged hearts. Exercise training inhibited the loss of preconditioning protection and restored the polyamine pool by activating ODC and inhibiting SSAT in aged hearts. An ODC inhibitor, α-difluoromethylornithine, abolished the recovery of preconditioning protection mediated by exercise. Moreover, polyamines improved age-associated mitochondrial dysfunction in vitro.
  
  
  CONCLUSIONS
  Exercise appears to restore preconditioning protection in aged rat hearts, possibly due to an increase in intracellular polyamines and an improvement in mitochondrial function in response to a preconditioning stimulus.
authors.affiliation: Department of Pathophysiology, Harbin Medical University, No. 157 Baojian Road, Nangang District, Harbin 150086, China.
authors.forename: Weiwei
authors.initials: W
authors.lastname: Wang
authors.affiliation: Department of Pathophysiology, Harbin Medical University, No. 157 Baojian Road, Nangang District, Harbin 150086, China.
authors.forename: Hao
authors.initials: H
authors.lastname: Zhang
authors.affiliation: Department of Pathology, Heilongjiang Electric Power Hospital, Harbin 150090, China.
authors.forename: Guo
authors.initials: G
authors.lastname: Xue
authors.affiliation: Department of Pathophysiology, Harbin Medical University, No. 157 Baojian Road, Nangang District, Harbin 150086, China.
authors.forename: Li
authors.identifier: 0000-0002-8968-8854
authors.initials: L
authors.lastname: Zhang
authors.affiliation: Department of Pathophysiology, Harbin Medical University, No. 157 Baojian Road, Nangang District, Harbin 150086, China.
authors.forename: Weihua
authors.initials: W
authors.lastname: Zhang
authors.affiliation: Department of Pathophysiology, Harbin Medical University, No. 157 Baojian Road, Nangang District, Harbin 150086, China.
authors.forename: Lina
authors.initials: L
authors.lastname: Wang
authors.affiliation: Department of Pathophysiology, Harbin Medical University, No. 157 Baojian Road, Nangang District, Harbin 150086, China.
authors.forename: Fanghao
authors.initials: F
authors.lastname: Lu
authors.affiliation: Department of Pathophysiology, Harbin Medical University, No. 157 Baojian Road, Nangang District, Harbin 150086, China.
authors.forename: Hongzhu
authors.initials: H
authors.lastname: Li
authors.affiliation: Department of Pathophysiology, Harbin Medical University, No. 157 Baojian Road, Nangang District, Harbin 150086, China.
authors.forename: Shuzhi
authors.initials: S
authors.lastname: Bai
authors.affiliation: Department of Pathophysiology, Qiqihar Medical University, Qiqihar 161006, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Lin
authors.affiliation: Department of Cardiology, The First Clinical Hospital of Harbin Medical University, Harbin 150001, China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Lou
authors.affiliation: Department of Pathophysiology, Harbin Medical University, No. 157 Baojian Road, Nangang District, Harbin 150086, China.
authors.forename: Changqing
authors.initials: C
authors.lastname: Xu
authors.affiliation: Department of Pathophysiology, Harbin Medical University, No. 157 Baojian Road, Nangang District, Harbin 150086, China.
authors.forename: Yajun
authors.initials: Y
authors.lastname: Zhao
mesh_terms: D000123:Acetyltransferases / Q000378:metabolism; D000367:Age Factors; D000818:Animals; D019157:Ischemic Preconditioning, Myocardial / Q000379:methods*; D008297:Male; D015428:Myocardial Reperfusion Injury / Q000378:metabolism / Q000517:prevention & control*; D009206:Myocardium / Q000378:metabolism*; D032383:Myocytes, Cardiac / Q000378:metabolism; D009955:Ornithine Decarboxylase / Q000378:metabolism; D010805:Physical Conditioning, Animal / Q000379:methods*; D011073:Polyamines / Q000378:metabolism*; D011897:Random Allocation; D051381:Rats; D017208:Rats, Wistar; D000099228:Diamine N-Acetyltransferase
chemical_list: D000123:Acetyltransferases; D009955:Ornithine Decarboxylase; D011073:Polyamines; D000099228:Diamine N-Acetyltransferase