Preservation of cell organelles during storage of human atrial tissue in the University of Wisconsin solution.

AIM OF THE STUDY

The University of Wisconsin storage solution (UW) (E.I. du Pont de Nemours, Wilmington, DE) has been successful in extending the storage period using some model systems of donor heart preservation for cardiac transplantation. The ability of UW to preserve human cardiac cell organelle (sarcoplasmic reticulum, mitochondria and sarcolemmal) membrane composition (enzyme activity, protein, cholesterol and phospholipid content) was compared to St. Thomas's Hospital Solution (ST) and saline.

METHODS

Human atrial appendages were stored at 4 degrees C for 24 h in saline, ST or UW or not stored (controls) and the cell organelles isolated. Each fraction was assayed for enzyme activity (mitochondria: azide sensitive Ca2+ ATPase, cytochrome C oxidase; sarcolemmal membrane: Na+K+ ATPase, p-nitrophenylphosphatase; sarcoplasmic reticulum: CA2+ uptake, Ca2+ ATPase, NADPH cytochrome C reductase), protein, cholesterol and phospholipid content.

RESULTS

"Protein yield" proved to be the most sensitive marker for cell organelle preservation. Only the sarcolemmal membrane showed no decrease in either enzyme activities of "protein yield" after storage in saline, ST or UW. Mitochondria showed no decrease in enzyme activities but a decrease in "protein yield" after storage in all 3 solutions. The "protein yield" of sarcoplasmic reticulum was significantly reduced after storage in UW, saline and ST. No correlation could be drawn between cholesterol and phospholipid content and the preservation of cell organelle function.

CONCLUSIONS

It is possible to distinguish between the ability of solutions to preserve the membrane composition of human cardiac tissue during hypothermic storage. Using simple assays to assess preservation provides preliminary screening for a superior solution which can then be used in more complicated transplantation models to more fully assess cardiac function.