We found a match
Your institution may have access to this item. Find your institution then sign in to continue.
- Title
Hypothermic protection of ischemic heart: <sup>13</sup>C NMR substrate analysis.
- Authors
Hyyti, Outi Maria; Xue-Han Ningt; Portman, Michael A.
- Abstract
Mechanisms for changes in myocardial metabolism in hypothermic protection stay unclear, though substrate contribution into citric acid cycle (CAC) may play a role. Specifically, acetoacetate (AA) has been shown to have antioxidant capabilities. We studied hypothermic protection and substrate contribution into CAC in heart. Isolated rat hearts formed 3 groups: control (C, 37°C, n=5), ischemic (IS, 37°C, n=5) and hypothermic ischemic (HIS, 28°C, n=3). HIS hearts were held at 28°C 25 min prior to and during 45 min cardioplegic arrest, after which all ischemic hearts were reperfused in 37°C. Perfusate included physiological concentrations of 13C labeled substrates: 1,3-AA, 3-lactate, U-mixed free fatty acids, unlabeled glucose. 13C NMR isotopomer analysis yielded fractional contributions (Fc) of substrates to CAC. HIS hearts tended to have a higher left ventricular developed pressure, pressure rate product and oxygen consumption at 35 min of reperfusion vs. IS. Fc of AA tended to increase in IS vs. C (0.33±0.02, 0.27±0.02, respectively). However, Fc of AA in HIS (0.254±0.03) was similar to C. Hypothermia improved cardiac function with C levels of AA Fc. Increased AA oxidation in IS might hinder detoxification of hydrogen peroxide produced by ischemia causing myocardial injury. These results suggest a link between AA oxidation and hypothermic protection. Support: NIH HL60666.
- Subjects
HYPOTHERMIA; HEART metabolism; ISCHEMIA; KREBS cycle; FATTY acids; GLUCOSE; HYDROGEN peroxide
- Publication
FASEB Journal, 2007, Vol 21, Issue 6, pA1377
- ISSN
0892-6638
- Publication type
Article
- DOI
10.1096/fasebj.21.6.a1377-a