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Loss of myocardial viability following hypothermic perfusion storage from contaminating trace elements in the
Insights
Higher concentrations of contaminating trace elements like iron in heart preservation solutions significantly impair organ function. This leads to reduced heart mass, poor coronary flow, and ultimately, transplant failure, highlighting the need for purity in cardioplegia.
Area of Science:
- Cardiovascular Surgery
- Organ Preservation
- Trace Element Toxicology
Background:
- Hypothermic perfusion storage is crucial for preserving donor hearts.
- Contaminating trace elements in perfusates may adversely affect organ viability.
- Understanding the impact of specific contaminants is vital for improving transplant outcomes.
Purpose of the Study:
- To investigate the effect of differing trace element concentrations (iron, lead, arsenic) in perfusates on baboon heart preservation.
- To determine the correlation between perfusate composition and post-transplant cardiac function.
- To explore the role of superoxide anion production in trace element-induced myocardial damage.
Main Methods:
- Isolated baboon hearts were preserved for 48 hours using two perfusates with varying trace element concentrations.
- Key parameters assessed included heart mass, coronary flow, and biochemical markers (lactate, LDH).
- Superoxide anion activity was measured in perfusates, with and without superoxide dismutase.
Main Results:
- Perfusate B (higher trace elements) resulted in less heart mass gain, reduced coronary flow, and elevated lactate dehydrogenase.
- Hearts preserved with perfusate B failed post-transplantation, unlike those preserved with perfusate A.
- Superoxide anion activity was significantly higher in perfusate B, inhibited by superoxide dismutase.
Conclusions:
- Elevated concentrations of contaminating trace elements, particularly iron, in preservation solutions negatively impact myocardial function.
- Trace element-induced superoxide production may contribute to myocardial injury during hypothermic storage.
- Perfusate purity is critical for successful long-term organ preservation and transplantation outcomes.
Abstract:
Two groups (A and B) of isolated baboon hearts were preserved by continuous hypothermic perfusion storage for 48 hours using perfusates that, according to the manufacturers, differed only in the concentrations of the contaminating trace elements iron, lead, and arsenic. Storage with the perfusate containing the higher concentration of these elements (perfusate B) led to significantly less gain in heart mass, a greater reduction in coronary flow, coronary sinus effluent lactate, and myocardial arteriovenous oxygen difference and a greater increase in coronary sinus effluent lactate dehydrogenase, when compared with perfusate A. Group B hearts totally failed to support the circulation following orthotopic transplantation, whereas group A hearts showed excellent function. Group B hearts had undergone the typical changes of enhanced resting myocardial tension during the storage period (before warm blood reperfusion); we proposed that these changes were brought about by the production of superoxide anions and radicals by the higher relative concentration of iron, or a combination of contaminating trace elements, in perfusate B. To confirm that these perfusates did differ significantly in the concentration of these trace elements, in particular with regard to iron, the superoxide anion activity in both solutions was measured and was found to be significantly higher in perfusate B. The addition of superoxide dismutase to both solutions inhibited superoxide anion activity by more than 80%.