Oral Presentation Society of Obstetric Medicine of Australia and New Zealand ASM 2015

Placental expression of mitochondrial transcription factors is affected by infant gender but not by late onset preeclampsia (#30)

Sarah Kugelman 1 2 , Helen L Barrett 1 2 3 , Leonie K Callaway 1 2 3 , Marloes Dekker Nitert 1 2
  1. School of Medicine, The University of Queensland, Herston, QLD, Australia
  2. UQ Centre for Clinical Research, The University of Queensland, Herston, QLD, Australia
  3. Obstetric Medicine, Royal Brisbane and Women's Hospital, Herston, QLD, Australia

Introduction: Preeclampsia is associated with placental dysfunction. There is a strong link between preeclampsia and insulin resistance, with increased rates of preeclampsia in women with insulin resistant conditions. Impaired mitochondrial function is observed in many different tissue types in individuals with insulin resistance.

Aim: This study aimed to determine whether expression of mitochondrial transcription factors known to be altered in insulin resistance (TFAM, TFB1M, TFB2M and NRF1) is altered in placentas from women with late onset preeclampsia.

Method: Placental samples were collected from 35 women: 16 with preeclampsia (7F, 8M, 1 unknown) and 19 matched controls (9F, 10M) at delivery. mRNA expression of placental mitochondrial transcription factors TFAM, TFB1M, TFB2M and NRF1 was measured using quantitative real-time PCR. Placental mitochondrial transcription factor expression was compared between women with and without preeclampsia and between male and female infants with non-parametric statistics.

Results: Late-onset preeclampsia did not affect the expression of any of the mitochondrial transcription factors. The expression of TFAM, NRF1 and TFB2M was significantly higher in male (n=18) than in female infants (n=17): TFAM Males median 1.22 (IQR 0.52-3.92) vs Females 0.63 (0.23-1.04), p<0.05; NRF1 Males 1.54 (0.98-3.49) vs. Females 0.63 (0.21-1.46), p<0.05; and TFB1M Males 1.86 (0.75-9.82) vs. Females 0.83 (0.32-1.80), p<0.05. Preeclampsia did not affect expression levels in placenta in either the male or female group. Expression of TFAM was strongly correlated with TFB1M (Spearman’s rho 0.94, p<0.0001) and TFB2M (rho 0.86, p<0.0001) expression but only weakly with NRF1 (rho 0.38, p<0.05). Expression of mitochondrial transcription factors in the placenta was not correlated to maternal prepregnancy BMI or infant birth weight.

Conclusion: Late-onset preeclampsia does not affect placental expression of mitochondrial transcription factors. Placental expression TFAM, TFB1M and NRF1 is increased in male infants, this could potentially contribute to increased energy supply.