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The use of myocytes as a model for developing successful heart preservation solutions
T Schmid1, G Landry, B L Fields
1Department of Surgery, University of Wisconsin, Madison 53792.
Insights
Isolated heart cells stored in University of Wisconsin solution with polyethylene glycol showed the best viability after cold storage. This myocyte model is useful for testing heart preservation solutions to improve transplant outcomes.
Area of Science:
- Cardiology
- Transplantation Biology
- Cellular Preservation
Background:
- Achieving long-term heart preservation (24-48 hours) for transplantation is challenging due to numerous variables.
- Studying these variables in complex orthotopic transplant models is difficult.
- Isolated myocyte preparations offer a simplified model to assess preservation parameters.
Purpose of the Study:
- To evaluate the suitability of an isolated rabbit heart myocyte model for assessing cold storage preservation.
- To compare the efficacy of various preservation solutions on myocyte viability over 24 hours.
Main Methods:
- Rabbit heart myocytes were isolated and stored for up to 24 hours in EuroCollins (EC), Stanford (ST), Bretschneider (HTK), and University of Wisconsin (UW) solutions, with and without polyethylene glycol (PEG).
- Myocyte viability was assessed by measuring cellular morphology (rod-shaped cells), adenosine triphosphate (ATP) concentration, and lactate dehydrogenase (LDH) release.
Main Results:
- Myocytes stored in cardioplegic solutions (HTK, ST) showed the poorest preservation, indicated by reduced rod-shaped morphology and lower ATP levels.
- EuroCollins (EC) solution resulted in greater loss of rod-shaped cells compared to UW solutions.
- University of Wisconsin (UW) solutions, particularly those with PEG, provided the best preservation of myocyte morphology and ATP content.
Conclusions:
- The isolated myocyte model effectively demonstrates cell integrity loss related to preservation solutions, mirroring findings from other heart preservation models.
- This model is a valuable tool for systematically testing preservation solutions and variables to optimize heart preservation.
- Future research using this model could lead to improved preservation solutions for clinical heart transplantation.
Abstract:
The development of a successful method to preserve the heart for relatively long periods (24-48 hr) requires demonstrating successful orthotopic transplantation and long-term survival after preservation. There are, however, multiple variables that may affect the quality of heart preservation, and it is nearly impossible to systematically study all the variables in this complicated model. One model that may be useful to study how preservation parameters affect heart cell preservation is the isolated myocyte preparation. In this study myocytes were isolated from the rabbit heart and the effects of up to 24 hr cold storage on viability measured to determine if this would be a suitable preservation model. Myocytes were stored in various preservation solutions including; EuroCollins (EC), two cardioplegic solutions (Stanford [ST] and Bretschneider solution [HTK]) and the University of Wisconsin solution (UW) with or without the addition of polyethylene glycol. The viability of myocytes was judged by measuring the effects of preservation and rewarming after preservation on cellular morphology (percent rod-shaped cells), ATP concentration, and LDH release. Myocytes preserved in the cardioplegic solutions were least well preserved after 12 and 24 hr storage, as judged by the loss of rod-shaped morphology and lower ATP concentration. Preservation in EC resulted in a decrease in the percent rod-shaped cells after 12 hr and 24 hr storage that was greater than obtained in the UW solutions. The best preservation of myocyte morphology and highest content of ATP was obtained in myocytes stored in the UW solutions, especially those containing PEG. The myocyte model of heart preservation shows a loss of cell integrity that is related to the preservation solution (HTK greater than ST greater than EC greater than UW-PEG) and these results are similar to what has been shown in the past with other models of heart preservation. Thus the myocyte model appears to be a useful method to test how many preservation solutions and preservation variables affect heart cell metabolism. In the future, results from these types of studies may find use in developing improved heart preservation solutions for testing in the orthotopic transplant model.