Decrease in cytochrome c oxidase and cytochrome oxidase subunit I messenger RNA levels in preeclamptic pregnancies.

OBJECTIVE

To elucidate the possible relation between mitochondrial gene expression and placental dysfunction.

METHODS

We measured the activity of cytochrome c oxidase and the expression of cytochrome oxidase subunit I in mitochondria from human placentas of women whose gestations were appropriate for gestational age (AGA) and those with preeclampsia. In addition, the amounts of normal mtDNA and deleted mitochondrial DNA were examined in the two groups by Southern blot analysis and polymerase chain reaction, respectively.

RESULTS

Cytochrome c oxidase activity and expression of cytochrome oxidase subunit I were significantly lower in the preeclamptic group than in the AGA group. There were no differences between the groups in the amounts of mitochondrial DNA. In addition, no mutant mitochondrial DNA with a 4977-base pair deletion was detected in the two groups.

CONCLUSION

These results suggest that reduced expression of the mitochondrial gene is involved in placental dysfunction in preeclamptic pregnancy.