Placental glycolysis and energy metabolism in preeclampsia

We examined the possibility that in preeclampsia complicated by fetal growth retardation, placental energy state is low either because of impaired glycolysis or because of ischemia resulting from reduced maternal placental blood flow. Concentrations of pyruvate and lactate, but not of glycogen and glucose, were significantly low in placentas of mothers with severe preeclampsia, supporting previous indirect evidence of inhibited glycolysis. Nevertheless, direct measurements of adenine nucleotide concentrations did not indicate reduced placental energy level in the preeclamptic placentas. This along with a lack of change of the ratio of lactatelpyruvate concentration (an indication of the redox state of cytoplasmic reduced nicotinamide-adenine dinucleotidelnicotinamide adenine dinucleotide) is also evidence against the hypothesis of general placental ischemia leading to energy deficiency. However, as glycolysis is an important source of precursors, particularly pyruvate, for synthesis of amino acids and lipids, these results suggest that there is a significant metabolic abnormality in placentas of mothers with severe preeclampsia.