Proteomic studies of VEGFR2 in human placentas reveal protein associations with preeclampsia, diabetes, gravidity, and labor.

VEGFR2 (Vascular endothelial growth factor receptor 2) is a central regulator of placental angiogenesis. The study of the VEGFR2 proteome of chorionic villi at term revealed its partners MDMX (Double minute 4 protein) and PICALM (Phosphatidylinositol-binding clathrin assembly protein). Subsequently, the oxytocin receptor (OT-R) and vasopressin V1aR receptor were detected in MDMX and PICALM immunoprecipitations. Immunogold electron microscopy showed VEGFR2 on endothelial cell (EC) nuclei, mitochondria, and Hofbauer cells (HC), tissue-resident macrophages of the placenta. MDMX, PICALM, and V1aR were located on EC plasma membranes, nuclei, and HC nuclei. Unexpectedly, PICALM and OT-R were detected on EC projections into the fetal lumen and OT-R on 20-150 nm clusters therein, prompting the hypothesis that placental exosomes transport OT-R to the fetus and across the blood-brain barrier. Insights on gestational complications were gained by univariable and multivariable regression analyses associating preeclampsia with lower MDMX protein levels in membrane extracts of chorionic villi, and lower MDMX, PICALM, OT-R, and V1aR with spontaneous vaginal deliveries compared to cesarean deliveries before the onset of labor. We found select associations between higher MDMX, PICALM, OT-R protein levels and either gravidity, diabetes, BMI, maternal age, or neonatal weight, and correlations only between PICALM-OT-R (p < 2.7 × 10-8), PICALM-V1aR (p < 0.006), and OT-R-V1aR (p < 0.001). These results offer for exploration new partnerships in metabolic networks, tissue-resident immunity, and labor, notably for HC that predominantly express MDMX.

Uterine activity in women receiving 17 alpha-hydroxyprogesterone caproate for the prevention of preterm birth: an observational study.

We evaluated uterine contraction frequency in women receiving 17 alpha-hydroxyprogesterone caproate (17-OHP-C) for the prevention of preterm delivery. Women with singleton pregnancies and receiving weekly 17-OHP-C and outpatient tococardiography were identified from a database. The mean and maximum contraction frequencies per hour were compared from 3 days before to 3 days after 17-OHP-C dosing. McNemar chi(2), Mann-Whitney U, and Friedman test statistics were used for analysis. Data were obtained from 388 women. Median contraction frequency was greater for women with subsequent preterm birth versus those delivering at term (1.5 [range 0, 14.5] versus 1.2 [range 0, 21.0] contractions per hour, P < 0.001). No reduction in contraction frequency was observed after 17-OHP-C administration, and in fact, the converse was observed for the average contractions 3 days prior compared with 3 days posttreatment ( P < 0.001). In the subgroup of women with a subsequent spontaneous preterm, the proportion who had an average contraction frequency of more than five per hour 1 day preinjection versus 1 day postinjection was not significantly different (2.6% versus 3.0%, P = 1.0). Administration of 17-OHP-C was not associated with a reduction in contraction frequency. To be effective, this drug likely has effects by mechanisms other than tocolysis. Although a statistically significant increase in contractions was identified posttherapy versus pretherapy, the clinical importance of this observation is unknown.