Enhancement of hypothermic heart preservation with fructose 1,6-diphosphate

Background. We hypothesized that the addition of fructose 1,6-diphosphate ( FDP) to a hypothermic heart preservation solution could improve metabolic r ecovery because it has several beneficial effects. Materials and Methods. Twenty adult Sprague-Dawley rats were used to study hypothermic heart preservation. The hearts were removed under general anest hesia and preserved at 4 degrees C in Euro-collins solution (30 ml/kg) for 8 h. In the study group (N = 10), FDP (5 mM) was added to the Euro-Collins solution. In the control group (N = 10), no FDP was added. Heart function w as studied after preservation using a working heart model. The ability of v arious concentrations of fructose 1,g-phosphate to passively diffuse throug h an egg phosphatidylcholine multilamellar vesicle (MLV) membrane bilayer w as examined. Results. Cardiac output ranged from 17.0 +/- 1.9 to 24.9 +/- 1.6 ml/min in the study group vs 2.0 +/- 1.0-12.3 +/- 1.7 ml/min for controls, average ao rtic how was 10.8 +/- 1.4 ml/min in the study group vs -1.3 +/- 1.6 ml/min for controls, and maximum LV generated power was 22.8 +/- 1.7 J/min vs 10.1 +/- 1.6 J/min for controls. Coronary how, left ventricular stroke volume a nd stroke work, and myocardial oxygen consumption were much higher in the s tudy group than in the control group. Coronary vascular resistance was lowe r in the study group than in the control group. Electron microscopic study indicated that many myocytes displayed patches of swollen mitochondria in t he control group, but was rarely observed in the study group. The addition of 50 mM FDP caused substantial changes in MLV permeability. No dose of suc rose buffers outside the vesicles resulted in a significant changes of MLV permeability. Conclusions Our results indicate that the addition of FDP to Euro-Collins s olution significantly improves hypothermic rat heart preservation, and FDP appeared to cross the membrane bilayer. (C) 1999 Academic Press.