Myocardial Preservation at Subzero Nonfreezing Temperature Storege

1996 Fiscal Year Final Research Report Summary

• Project/Area Number: 07671485
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Thoracic surgery
• Research Institution: Ehime university (1996); Nara Medical University (1995)
• Principal Investigator: KAWACHI Kanji Medicine Professor, 医学部, 教授 (90116020)
• Co-Investigator(Kenkyū-buntansha): NIWAYA Kazuo Nara medical college Assistant, 医学部, 助手 (30254501) ; KOBAYASHI Shuichi Nara medical college Assistant, 医学部, 助手 (50201489)
• Project Period (FY): 1995 – 1996
• Keywords: Heart storage / adenine nucleotides / Subzero nonfreezing storage / supercooling

Research Abstract

BACKGROUND : The hypothermic simple immersion technique has been widely used to preserve the donor heart for transplantation. However, there is still controversy as to which temperature provides the best protection against prolonged ischemia. The low molecular weight solutes within cells depress the freezing point to -0.6ﾟC.In practice, however, most cells do not freeze internally unless they are cooled below -10ﾟC.We investigated the effects of subzero nonfreezing storage at -1ﾟC on the preservation of myocardial metabolism and function.
METHODS : Isolated Wistar rat hearts were subjected to 6 hours of preservation using the intracellular type University of Wisconsin solution ; the hearts of subzero group were preserved at subzero nonfreezing (-1ﾟC) temperature, and the hearts of control group were at 4ﾟC.Recovery of cardiac function, myocardial adenine nucleotides content and myocardial water content were evaluated after preservation.
RESULTS : Subzero group resulted in significantly better aortic flow, cardiac output, and aortic systolic pressure than control group. Myocardial adenosine triphosphate, adenosine diphosphate, and total adenine nucleotides at end-storage were significantly better preserved in subzero group when compared with control group. Myocardial water content at reperfusion significantly increased in the control group compared with subzero group.
CONCLUSIONS : Storage in the intracellular type solution at subzero nonfreezing (-1ﾟC) temperature as compared with 4ﾟC appears to prolong myocardial preservation with respect to the enhancement of postischemic functional recovery, preservation of myocardial adenine nucleotides during ischemia and prevention of myocardial edema at reperfusion.