Improved cardiac preservation by the addition of nitroglycerine to colloid-free University of Wisconsin solution (MUW)

Supplementation of nucleoside-nucleotide mixture enhances functional recovery and energy metabolism following long-time hypothermic heart preservation

BACKGROUND

OG-VI, a well-balanced mixture of nucleoside and nucleotides, has been demonstrated to have a favorable effect on energy metabolism. In this study, we tested the hypothesis that addition of OG-VI to the University of Wisconsin solution can improve the cardiac functional recovery following long-time hypothermic preservation.

MATERIALS AND METHODS

Forty-two male Wistar rats were randomized into four groups. After 30-min of isolated working heart perfusion, the rat hearts were arrested with St. Thomas cardioplegic solution and preserved at 4 degrees C in saline, OG-VI, UW, and UW+OG-VI, respectively. After 12-h of preservation, the hearts were reperfused for 60-min during which the recovery of cardiac functions were monitored continuously. Myocardial adenine nucleotides were analyzed using high-performance liquid chromomatograph.

RESULTS

In the UW+OG-VI group, the recovery of cardiac output, coronary flow, aortic flow, rate-pressure product, left ventricle stroke volume, and stroke work were significantly higher than other groups (P < 0.05). Furthermore, all phosphate high-energy compounds were significantly higher in the UW+OG-VI group than in the other groups (P < 0.05). Coronary vascular resistance and myocardial wet/dry weight ratio were obviously lower in the UW+OG-VI group, compared to the other groups (P < 0.05).

CONCLUSIONS

Heart function was better recovered when nucleoside-nucleotide mixture was added to UW solution during long-time hypothermic rat heart preservation. The mechanism is not totally clear, but enhancement of high-energy phosphate production is possible.

Heart preservation with celsior solution improved by the addition of nitroglycerine

BACKGROUND

Preservation of rat hearts was extended to 16 hr when nitroglycerine (NTG) was added to colloid-free University of Wisconsin solution (MUW). This study examined the effectiveness of Celsior solution (CEL) and whether adding NTG to CEL would improve and extend cardiac preservation.

METHODS

Two studies were conducted: (a) 9-hr preservation with either CEL or MUW, (b) 16-hr preservation with CEL, CEL+NTG, or MUW+NTG. Rat heart isografts were flushed and stored at 0 degrees C before heterotopic transplantation with an indwelling externalized intraventricular balloon-tipped catheter. One and 7 days after transplantation, quantitative functional studies were performed.

RESULTS

After 9-hr preservation, all (6/6) grafts preserved with MUW beat for 7 days, whereas only 1/6 hearts preserved with CEL continued to beat. After 16-hr preservation, 6/10 CEL+NTG hearts beat for 7 days compared with 7/8 MUW+NTG hearts; none of the hearts preserved with CEL survived. Function was similar in CEL+NTG and MUW+NTG groups on day 1 (left ventricular developed pressure (LVDP): CEL+NTG=64+/-16, MUW+NTG=104+/-16 mmHg; maximum dP/dt: CEL+ NTG=2024+/-551, MUW+NTG=3582+/-513 mmHg/sec) and day 7: (LVDP: CEL+NTG=126+/-25, MUW+NTG=177+/-24 mmHg; maximum dP/dt: CEL+NTG=3835+/-848, MUW+ NTG=5639+/-670 mmHg/sec). Function in both groups improved significantly (P<0.05) on day 7 compared with day 1.

CONCLUSIONS

Celsior was not as effective as MUW for rat heart preservation. The addition of NTG to both CEL and MUW provided similar effective preservation for 16 hr. NTG should be added routinely to both solutions.

Hypothermic storage of coronary endothelial cells reduces nitric oxide synthase activity and expression

Preservation with University of Wisconsin (UW) solution has been implicated in coronary artery endothelial damage and loss of endothelium-dependent vasodilatation. Therefore, the objective of this study was to investigate the effect of this solution on basal nitric oxide (NO) release from porcine coronary endothelial cells (CEC). Cultures were exposed to cold (4 degrees C) storage in UW solution for 6, 8 and 12 h. Parallel cultures were incubated with control medium at 37 degrees C. After treatment, NO release was evaluated by nitrite production, a stable metabolite of NO. Activity of the constitutive endothelial nitric oxide synthase (eNOS) was measured by the conversion [3H]-l-arginine to [3H]-l-citrulline and eNOS protein expression by Western blotting. Nitrite production by control cells was augmented with increasing times of incubation, whereas no change was observed in those cultures preserved with UW solution. Activity of eNOS was significantly decreased compared to the respective control group by cold storage of cells for longer periods than 6 h. Such decrease was correlated with a diminished eNOS protein expression in CEC preserved with UW solution after 8- and 12-h storage. These results suggest that prolonged hypothermic storage of CEC with UW solution does not preserve basal NO release because of a certain loss of eNOS protein, which may contribute to the reported injury of heart transplants after long-term preservation.