Water and Electrolyte Structural Studies on Homotransplanted Hearts

Abstract

Twelve young dog hearts were transplanted to the necks of healthy adult dogs for planned periods of time varying from three to 90 hours. All transplants were functioning at the time of sacrifice. After histochemical studies for water, chloride, sodium, potassium, calcium and magnesium, the following deductions were made: (1) In the host tissues (heart, serum, and blood cells) the values for water, chloride, sodium, calcium, magnesium and potassium were normal with only small deviations. (2) In the transplanted heart when the tissue compartments are considered two factors were evident: (a) The concentration of the intracellular constituents of potassium, magnesium, non-collagenous nitrogen and water showed little change when compared to the normal or host heart; (b) the extracellular values for chloride, sodium, calcium and water were remarkably elevated. The increase in water was entirely in the ultrafiltrate volume. While the architecture of the myocardial fiber appears to remain normal during the considered periods of transplantation, acute edema occurred in the extracellular compartment of the tissue and there was an increase in tissue calcium. We are unable at this time to speculate on the effect of these findings on the eventual failure of the homograft.