DNA flow cytometry of myocardial cell nuclei in paraffin-embedded, human autopsy, cardiac tissue

Changes in nuclear DNA occur in myocytes as they grow and hypertrophy. We used DNA flow cytometry to study myocardial nuclei from paraffin-embedded human autopsy tissue. Forty hearts ranging from 310-1040 g were studied. Histograms generated for each heart showed peaks at the 2N and 4N positions. Two of 9 hearts weighing 310-430 g had 8N peaks as well. Fourteen of 17 hearts weighing 450-690 g also had 8N peaks but no 16N peaks. Twelve of 14 hearts weighing 710 to 1040 g had 8N peaks and 4 had 16N peaks as well. Contingency analysis showed statistically significant differences in the ploidy of nuclei from the three different groups of hearts. This study corroborates previous work indicating that DNA ploidy in myocardium increases with hypertrophy. Thus, flow cytometry of paraffin-embedded myocardium should be a useful technique to study DNA from archival material, obviating the need for fresh or frozen tissue.