Gestation age-associated dynamics of mitochondrial calcium uniporter subunits expression in feto-maternal complex at term and preterm delivery.

Calcium plays a role of universal cellular regulator in the living cell and one of the crucial regulators of proper fetal development during gestation. Mitochondria are important for intracellular calcium handling and signaling. Mitochondrial calcium uniporter (mtCU) is a multiprotein complex of the mitochondrial inner membrane responsible for the transport of calcium to the mitochondrial matrix. In the present study, we analyzed the expression level of mtCU components in two parts of the feto-maternal system - placenta and myometrium at full-term delivery and at preterm birth (PTB) on different stages: 22-27, 28-32, 33-36 weeks of gestation (n = 50). A gradual increase of mRNA expression and changes in protein content of MCU and MICU1 subunits were revealed in the placenta during gestation. We also observed slower depolarization rate of isolated placental mitochondria induced by Ca2+ titration at PTB. In myometrium at PTB relative gene expression level of MCU, MCUb and SMDT1 increased as compared to full-term pregnancy, but the tendency to gradual increase of MCU protein simultaneous with MCUb increase and MICU1 decline was shown in gestational dynamics. Changes observed in the present study might be considered both natural dynamics as well as possible pathological mechanisms underlying preterm birth.

Cumulus cell mitochondrial activity in relation to body mass index in women undergoing assisted reproductive therapy.

Most studies have considered the negative influence of obesity on fertility in both genders. In the present study, we assessed mitochondrial activity expressed as the mitochondrial potential index (MPI) in cumulus cells from obese women and women with a normal body mass index (BMI) during assisted reproductive therapy. The results revealed a significant reduction of MPI with increased body mass. The lower MPI levels in cumulus cells from obese women may reflect mitochondrial dysfunction caused by oxidative stress, which can affect the cumulus-oocyte complex and have an impact on oocyte development.

Mitochondrial role in adaptive response to stress conditions in preeclampsia.

Preeclampsia (PE) is a pregnancy-specific syndrome, characterized in general by hypertension with proteinuria or other systemic disturbances. PE is the major cause of maternal and fetal morbidity and mortality worldwide. However, the etiology of PE still remains unclear. Our study involved 38 patients: 14 with uncomplicated pregnancy; 13 with early-onset PE (eoPE); and 11 with late-onset PE (loPE). We characterized the immunophenotype of cells isolated from the placenta and all biopsy samples were stained positive for Cytokeratin 7, SOX2, Nestin, Vimentin, and CD44. We obtained a significant increase in OPA1 mRNA and protein expression in the eoPE placentas. Moreover, TFAM expression was down-regulated in comparison to the control (p < 0.01). Mitochondrial DNA copy number in eoPE placentas was significantly higher than in samples from normal pregnancies. We observed an increase of maximum coupled state 3 respiration rate in mitochondria isolated from the placenta in the presence of complex I substrates in the eoPE group and an increase of P/O ratio, citrate synthase activity and decrease of Ca(2+)-induced depolarization rate in both PE groups. Our results suggest an essential role of mitochondrial activity changes in an adaptive response to the development of PE.