Relative distribution of estrone, estradiol and estriol between fetal and maternal perfusates during perfusions of human term placentas with labelled C19 precursors

The artificial uterus: on the way to ectogenesis

The inability to support the growth and development of a mature fetus up to delivery results in significant human suffering. Current available solutions include adoption, surrogacy, and uterus transplantation. However, these options are subject to several ethical, religious, economic, social, and medical concerns. Ectogenesis is the process in which an embryo develops in an artificial uterus from implantation through to the delivery of a live infant. This current narrative review summarizes the state of recent research focused on human ectogenesis. First, a literature search was performed to identify published reports of previous experiments and devices used for embryo implantation in an extracorporeally perfused human uterus. Furthermore, studies fitting that aim were selected and critically evaluated. Results were synthesized, interpreted, and used to design a prospective strategy for future research. Therefore, this study suggests that full ectogenesis might be obtained using a computer-controlled system with extracorporeal blood perfusion provided by a digitally controlled heart-lung-kidney system. From a clinical perspective, patients who will derive significant benefits from this technology are mainly those women diagnosed with anatomical abnormalities of the uterus and those who have undergone previous hysterectomies, numerous abortions, and experienced premature birth. Ectogenesis is the complete development of an embryo in an artificial uterus. It represents the solutions for millions of women suffering from premature deliveries, and the inability to supply growth and development of embryos/fetuses in the womb. In the future, ectogenesis might replace uterine transplantation and surrogacy.

Early Second Trimester Maternal Serum Steroid-Related Biomarkers Associated with Autism Spectrum Disorder

Epidemiologic studies link increased autism spectrum disorder (ASD) risk to obstetrical conditions associated with inflammation and steroid dysregulation, referred to as prenatal metabolic syndrome (PNMS). This pilot study measured steroid-related biomarkers in early second trimester maternal serum collected during the first and second trimester evaluation of risk study. ASD case and PNMS exposure status of index offspring were determined through linkage with autism registries and birth certificate records. ASD case (N = 53) and control (N = 19) groups were enriched for PNMS exposure. Higher estradiol and lower sex hormone binding globulin (SHBG) were significantly associated with increased ASD risk. Study findings provide preliminary evidence to link greater placental estradiol activity with ASD and support future investigations of the prenatal steroid environment in ASD.

The artificial womb

The availability of computer-controlled artificial hearts, kidneys, and lungs, as well as the possibility of implanting human embryos in ex vivo uterus models or an artificial endometrium, presents new perspectives for creating an artificial uterus. Survival rates have also improved, with fetuses surviving from as early as 24 weeks of gestation. These advances bring new opportunities for complete or partial ectogenesis through the creation of an artificial womb, one that could sustain the growth and development of fetuses outside of the human body.

Serum concentration and urinary excretion of "classical" estrogens, catecholestrogens and 2-methoxyestrogens in normal human pregnancy

Catecholestrogens, 2-methoxyestrogens and "classical" estrogens (estrone, estradiol, estriol) were measured simultaneously in serum and urine samples of 220 pregnant women from the 8th week of pregnancy until to delivery. From these data we established the central 0.80 centile intervals as time specified reference intervals for each substance analyzed. Serum and urinary estradiol rise steadily during the progress of pregnancy, whereas estrone, catecholestrogens and 2-methoxyestrogens reach a plateau during the last trimester. These observations support the hypothesis, that the amount of the latter compounds may be regulated by separate mechanisms. The values of concentration and excretion of 2- and 4-substituted estrogens varied widely throughout pregnancy. Even very high or very low concentrations of these substances had no recognizable relation to the outcome of pregnancy. This supports the assumption that catecholestrogens and their methylethers are metabolites without any regulatory function in pregnancy.

Inhibition of human placental aromatase in a perfusion model. Comparison with kinetic, cell-free experiments

In vitro perfusion of human placenta was evaluated for characterization of aromatase inhibitors. The results were compared with those in kinetic experiments in cell-free system. Inhibition constants (Ki) were determined by measuring the release of tritiated water during coincubation of human placenta microsomes with varying amounts of [1 beta,2 beta 3H]androstenedione and inhibitor in the presence of NADPH-generating system. Irreversible inactivation constants (Kinact) were determined in a similar manner following preincubation of the microsomes with different amounts of inhibitor for varying times. Lineweaver-Burk plots indicated a competitive type of inhibition with Ki values of 37 nM for 4-hydroxy-androstenedione, 3,700 nM for testolactone, 15 nM for 1-methyl-androsta-1,4-diene-3,17-dione, and 7.5 nM for 19-azido-androstenedione. Additionally, irreversible enzyme inactivation by all four substances could be demonstrated with Kinact values of 3.64 x 10(-3), 0.57 x 10(-3), 0.34 x 10(-3), and 0.69 x 10(-3)sec-1, respectively. Perfusion of a single cotyledon of human term placenta was performed by infusing medium through catheters placed in a fetal artery and in the maternal intervillous space. Perfused medium was collected from a cannulated fetal vein and from the maternal basal plate. The medium was supplemented with [3H]androstenedione (4.2 nM) and inhibitor. The perfusates were analyzed for their [3H]estrone and estradiol content following phenolic partition and Sephadex-LH 20 chromatography. The main results were, (1) the recovery of labelled steroids increased rapidly after perfusion started and reached a plateau within 60 min, when 55 and 30% (mean values) of the infused radioactivity were recovered in the fetal and maternal perfusates, respectively, (2) similar amounts of estrone and estradiol were found in both effluates, whereas androgens (mainly androstenedione and lower amounts of 5 alpha-androstane-3,17-dione) were found nearly exclusively in the fetal perfusate, (3) formation of estrogens (estrone + estradiol) reached a plateau within 20 min of perfusion. (4) The percentage of estrogens formed was not changed by increasing androstenedione concentration in the perfusion medium unless this concentration exceeded 3.5 microM indicating limited capacity of aromatase. (5) The four aromatase inhibitors reduced estrogen formation by 50% at concentrations about 100-fold of their Ki determined in the cell-free system, (6) irreversible aromatase inhibition could not be demonstrated in the perfusion model. It was concluded that the human placenta perfusion model can be successfully used to evaluate aromatase inhibitors.

A 48-hour preservation of an isolated human uterus: endometrial responses to sex steroids

Human uteri were perfused with Krebs-Ringer bicarbonate-glucose buffer with and without estrogens and progesterone for a period of up to 48 hours to preserve a viable organ, which was responsive to hormones. Flow rates of 12 to 35 ml/minute per artery were fully distributed into the organ, with pressure values ranging from 80 to 120 mm Hg. Arteriovenous gradients of oxygen and carbon dioxide tensions as well as the levels of lactate, lactic dehydrogenase, and creatine kinase released in the perfusate, indicators of tissue ischemia or cell necrosis, showed a good preservation of the organ for up to 48 hours. The light- and electron-microscopic examinations of endometrial and myometrial tissues taken before and during perfusion confirmed this result. The extracorporeal perfusion of uteri with buffer containing estrogens plus progesterone exhibited secretive modifications of the proliferative endometrium, thus suggesting the viability of the organ and its responsiveness to sex steroids.