Mark P. Leondires

Effects of estradiol and progesterone administration on human serotonin 2A receptor binding: a PET study

BACKGROUND Preclinical studies demonstrate that 17beta-estradiol (E(2)) increases serotonin-2A receptor (5-HT(2A)R) density in rat frontal cortex. METHODS We investigated the impact of hormone replacement therapy on 5-HT(2A)R binding potential (BP) using positron emission tomography and [(18)F]altanserin in five postmenopausal women. Subjects were imaged at baseline, following 8 to 14 weeks of transdermal E(2), 0.1 mg/d, and following 2 to 6 weeks of E(2) plus micronized progesterone (P) 100 mg per os twice daily. Regional BPs in the anterior cingulate cortex, dorsolateral prefrontal cortex, and lateral orbitofrontal cortex were calculated by Logan analysis. RESULTS There was a main effect of time (p = .017) for 5-HT(2A)R BP, which increased 21.2%+/-2.6% following combined E(2) and P administration relative to baseline. This effect was evident in all cerebral cortex regions examined. CONCLUSIONS 5-HT(2A)R BP increased in widespread areas of the cerebral cortex following combined E(2) + P administration.

Clinically recognizable error rate after the transfer of comprehensive chromosomal screened euploid embryos is low

OBJECTIVE To determine the clinically recognizable error rate with the use of quantitative polymerase chain reaction (qPCR)-based comprehensive chromosomal screening (CCS). DESIGN Retrospective study. SETTING Multiple fertility centers. PATIENT(S) All patients receiving euploid designated embryos. INTERVENTION(S) Trophectoderm biopsy for CCS. MAIN OUTCOME MEASURE(S) Evaluation of the pregnancy outcomes following the transfer of qPCR-designated euploid embryos. Calculation of the clinically recognizable error rate. RESULT(S) A total of 3,168 transfers led to 2,354 pregnancies (74.3%). Of 4,794 CCS euploid embryos transferred, 2,976 gestational sacs developed, reflecting a clinical implantation rate of 62.1%. In the cases where a miscarriage occurred and products of conception were available for analysis, ten were ultimately found to be aneuploid. Seven were identified in the products of conception following clinical losses and three in ongoing pregnancies. The clinically recognizable error rate per embryo designated as euploid was 0.21% (95% confidence interval [CI] 0.10-0.37). The clinically recognizable error rate per transfer was 0.32% (95% CI 0.16-0.56). The clinically recognizable error rate per ongoing pregnancy was 0.13% (95% CI 0.03-0.37). Three products of conception from aneuploid losses were available to the molecular laboratory for detailed examination, and all of them demonstrated fetal mosaicism. CONCLUSION(S) The clinically recognizable error rate with qPCR-based CCS is real but quite low. Although evaluated in only a limited number of specimens, mosaicism appears to play a prominent role in misdiagnoses. Mosaic errors present a genuine limit to the effectiveness of aneuploidy screening, because they are not attributable to technical issues in the embryology or analytic laboratories.

Estradiol stimulates expression of two human prolactin receptor isoforms with alternative exons-1 in T47D breast cancer cells

Human prolactin receptor (hPRLR) expression is regulated by estradiol-17beta (E(2)) in vivo in animal tissues, and in vitro in normal human endometrial cells and in MCF7 human breast cancer cells. The objective of this study was to determine the effect of E(2) on the expression of two recently described hPRLR isoforms with distinct exons-1, hE1(3) and hE1(N1) that are transcribed from the generic hPIII promoter, also present in the rat and mouse, and the human-specific promoter hP(N1), respectively. Also, to determine the effect of estradiol on the hPIII promoter activity in cancer cells. T47D breast cancer cells were examined using quantitative competitive RT-PCR for the level of expression of two alternative non-coding exon-1 transcripts, hE1(3) and hE1(N1) following incubation with E(2) in presence or absence of the E(2) receptor antagonist ICI 182,780. The effects of estradiol were also evaluated in cells transiently transfected with constructs of hPIII promoter luciferase reporter gene. E(2) significantly increased the expression of both hPRLR mRNA transcripts, hE1(3) and hE1(N1). In transfection studies E(2) activated the hPIII promoter. This effect of estradiol was markedly inhibited by coincubation with the E(2) receptor antagonist. Our results demonstrate a stimulatory effect of estradiol on the expression of hPRLR mRNA species with alternative exons-1, hE1(3) and hE1(N1) possibly through activation of their corresponding promoters. The lack of a formal ERE in these promoters suggested that the effect of estradiol is mediated through association of the activated ER with relevant DNA binding transfactor(s). These findings support the role of E(2) in the regulation of hPRLR expression in human breast cancer cell lines.

The Use of Antiestrogens in the Postmenopausal Woman

As women enter the menopause, endogenous estrogen levels fall and this state of estrogen deficiency contributes to several age-related health problems in women. Postmenopausal estrogen replacement therapy (ERT) is designed to take advantage of the positive health benefits of estrogen action in women, which include osteoporosis protection, reduction of cardiovascular risk, urogenital health, improved mood, and possibly, a reduction in Alzheimer’ s disease risk (1–3). Acceptance of ERT for postmenopausal women by both patients and practitioners has been limited by multiple concerns, including an increased risk of endometrial cancer for those on unopposed ERT; a possible, albeit small, increased risk of breast cancer, discontent with concomitant progestin therapy, and the undesired resumption of vaginal bleeding associated with cyclical therapy. Since the introduction of tamoxifen in 1978 and appreciation of its tissue-specific estrogenic and antiestrogenic actions (see the next section), many compounds have been designed to mimic or ablate the estrogenic signal in a tissue-specific fashion. Distinct tissue responsivity to estrogenic compounds is mediated by at least two distinct receptors, as well as, associated nuclear receptor binding proteins, binding to other receptors, and likely additional undefined factors. Because there have been many recent developments in the mechanisms of estrogen and antiestrogen action, this chapter is organized in three parts: the mechanisms of estrogen/antiestrogen action, the pharmacology and design of antiestrogens, and a description of antiestrogens in clinical use for postmenopausal women.