title: Deficient expression of monoamine oxidase A in the endometrium is associated with implantation failure in women participating as recipients in oocyte donation.
abstract: Successful implantation depends both on the quality of the embryo and on the endometrial receptivity. The latter depends on progesterone-induced changes in gene expression, a process that has been characterized by microarray analysis. One of the genes whose transcription appears to be enhanced during the receptive period is monoamine oxidase A (MAO-A). Our first objective was to confirm the increased expression of MAO-A in the endometrium during the receptive phase of spontaneous normal cycles using real time PCR and immunofluorescence. The second objective was to examine the endometrial expression of MAO-A during the receptive phase induced by exogenous estradiol (E(2)) and progesterone in patients whose endometrium was shown to have been either receptive or non-receptive to embryo implantation in repeated cycles of oocyte donation. Results showed that MAO-A transcript levels increased between the pre-receptive (LH+3) and receptive phase (LH+7) in all spontaneous cycles examined, with a median increase of 25-fold. Immunofluorescent labelling demonstrated MAO-A localization to the glandular and luminal epithelium with an increasing positive score between LH+3 and LH+7. Conversely, prior failure of embryo implantation was associated with a 29-fold decrease in MAO-A mRNA levels and a substantial reduction in MAO-A protein immunofluorescent label score. These results show a strong association between endometrial receptivity and MAO-A expression in the endometrial epithelium, suggesting an important role for this enzyme in normal implantation.
authors.affiliation: Laboratorio de Inmunología de la Reproducción, Universidad de Santiago de Chile.
authors.forename: S
authors.initials: S
authors.lastname: Henriquez
authors.forename: A
authors.initials: A
authors.lastname: Tapia
authors.forename: M
authors.initials: M
authors.lastname: Quezada
authors.forename: M
authors.initials: M
authors.lastname: Vargas
authors.forename: H
authors.initials: H
authors.lastname: Cardenas
authors.forename: M
authors.initials: M
authors.lastname: Rios
authors.forename: A M
authors.initials: AM
authors.lastname: Salvatierra
authors.forename: H
authors.initials: H
authors.lastname: Croxatto
authors.forename: P
authors.initials: P
authors.lastname: Orihuela
authors.forename: F
authors.initials: F
authors.lastname: Zegers-Hochschild
authors.forename: D J
authors.initials: DJ
authors.lastname: Munroe
authors.forename: L
authors.initials: L
authors.lastname: Velasquez
mesh_terms: D000328:Adult; D010064:Embryo Implantation / Q000502:physiology*; D020964:Embryo Loss / Q000209:etiology*; D004717:Endometrium / Q000201:enzymology*; D004790:Enzyme Induction; D004847:Epithelial Cells / Q000201:enzymology; D004958:Estradiol / Q000494:pharmacology; D005260:Female; D006801:Humans; D007247:Infertility, Female / Q000201:enzymology* / Q000503:physiopathology; D008183:Luteal Phase; D008995:Monoamine Oxidase / Q000096:biosynthesis / Q000172:deficiency* / Q000235:genetics / Q000502:physiology; D018587:Oocyte Donation; D010062:Ovulation Induction; D011374:Progesterone / Q000494:pharmacology; D012333:RNA, Messenger / Q000096:biosynthesis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017154:Stromal Cells / Q000201:enzymology
chemical_list: D012333:RNA, Messenger; D011374:Progesterone; D004958:Estradiol; D008995:Monoamine Oxidase