title: Donor pretreatment with adenosine monophosphate-activated protein kinase activator protects cardiac grafts from cold ischaemia/reperfusion injury.
abstract: OBJECTIVE
  Adenosine monophosphate-activated protein kinase (AMPK) is a master regulator of energy metabolism and has been shown to be protective in ischaemia/reperfusion injury (IRI). We hypothesized that preactivation of AMPK with an activator before donor heart procurement could protect heart grafts from cold IRI.
  
  
  METHODS
  Donor Sprague-Dawley rats were injected intravenously with AMPK activator 5-amino-imidazole-4-carboxamide ribonucleotide (AICAR) or vehicle 30 min before heart procurement. Heart grafts were then preserved in histidine-tryptophan-ketoglutarate (HTK) solution at 4°C for 8 h. After preservation, grafts were immediately mounted on the Langendorff perfusion system and perfused with Krebs-Henseleit buffer at 37°C for 1 h. Adenosine triphosphate (ATP) and malondialdehyde (MDA) content in graft tissue were quantified post-preservation and post-reperfusion. After reperfusion, isolated heart function was assessed using a pressure transducer; cumulative release of creatine kinase (CK) and lactate dehydrogenase (LDH) into the perfusate was measured to assess cardiomyocyte necrosis; ultrastructural changes in the mitochondria of the grafts were examined using transmission electron microscopy (TEM).
  
  
  RESULTS
  After preservation, myocardial ATP content in the pretreated hearts was significantly higher than in the control hearts (3.247 ± 0.3034 vs 1.817 ± 0.2533 µmol/g protein; P < 0.05). AICAR-pretreated heart grafts exhibited significantly higher coronary flow (9.667 ± 0.3159 vs 8.033 ± 0.2459 ml/min; P < 0.05) and left ventricular developing pressure (58.67 ± 2.894 vs 42.67 ± 3.333 mmHg; P < 0.05) than the vehicle treated after reperfusion. Cumulative release of CK (300.0 ± 25.30 vs 431.7 ± 42.39 U/l; P < 0.05) and LDH (228.0 ± 16.68 vs 366.8 ± 57.41 U/l; P < 0.05) in the perfusate was significantly lower in the AICAR-pretreated group than that in the control group. Myocardial MDA content was also reduced in the pretreated group (0.5167 ± 0.1046 vs 0.9333 ± 0.1333 nmol/mg protein; P < 0.05). TEM suggested that the mitochondrial structure of AICAR-pretreated hearts was much better preserved. Moreover, AICAR-pretreated hearts significantly diminished cytosolic cytochrome c release after reperfusion.
  
  
  CONCLUSIONS
  This study demonstrates that pretreatment with AMPK activator AICAR significantly protects heart grafts from extended cold IRI. This novel protocol may be useful and feasible in clinical heart transplantation.
authors.affiliation: Institute of Organ Transplantation, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China Key Laboratory of Organ Transplantation, Ministry of Health, and Key Laboratory of Organ Transplantation, Ministry of Education, Wuhan, China.
authors.forename: Chao
authors.initials: C
authors.lastname: Yang
authors.affiliation: Department of Hepatobiliary Surgery, The People's Hospital of Liuzhou, Liuzhou, China.
authors.forename: Honglai
authors.initials: H
authors.lastname: Xu
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
authors.forename: Lanjun
authors.initials: L
authors.lastname: Cai
authors.affiliation: Institute of Organ Transplantation, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China Key Laboratory of Organ Transplantation, Ministry of Health, and Key Laboratory of Organ Transplantation, Ministry of Education, Wuhan, China.
authors.forename: Xiaoxiao
authors.initials: X
authors.lastname: Du
authors.affiliation: Institute of Organ Transplantation, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China Key Laboratory of Organ Transplantation, Ministry of Health, and Key Laboratory of Organ Transplantation, Ministry of Education, Wuhan, China.
authors.forename: Yinan
authors.initials: Y
authors.lastname: Jiang
authors.affiliation: Institute of Organ Transplantation, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China Key Laboratory of Organ Transplantation, Ministry of Health, and Key Laboratory of Organ Transplantation, Ministry of Education, Wuhan, China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Cardiothoracic Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China amzhmin@126.com zc104@medmail.com.cn.
authors.forename: Hongmin
authors.initials: H
authors.lastname: Zhou
authors.affiliation: Institute of Organ Transplantation, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China Key Laboratory of Organ Transplantation, Ministry of Health, and Key Laboratory of Organ Transplantation, Ministry of Education, Wuhan, China amzhmin@126.com zc104@medmail.com.cn.
authors.forename: Zhonghua Klaus
authors.initials: ZK
authors.lastname: Chen
mesh_terms: D000249:Adenosine Monophosphate / Q000627:therapeutic use*; D000818:Animals; D006321:Heart / Q000502:physiology; D016027:Heart Transplantation; D007036:Hypothermia, Induced / Q000379:methods*; D008297:Male; D019188:Organ Preservation Solutions / Q000627:therapeutic use*; D051381:Rats; D017207:Rats, Sprague-Dawley; D015427:Reperfusion Injury / Q000517:prevention & control*; D014019:Tissue Donors; D014021:Tissue Preservation; D019737:Transplants
chemical_list: D019188:Organ Preservation Solutions; D000249:Adenosine Monophosphate
keywords: AMPK; Cold preservation; Heart transplantation; Ischaemia/reperfusion injury