Interacción endometrio trofoblasto, en la implantación humana: revisión de la literatura / Endometrium-trophoblast interaction in human implantation: review of literature

Un embarazo exitoso requiere de una serie de interacciones mediadas por factores hormonales, moleculares y fenómenos de inmunomodulación. Una de estas interacciones es la que ocurre entre el endometrio y el blastocito, previo y durante el proceso de implantación. El objetivo de esta revisión bibliográfica es complementar lo descrito en la literatura clásica de embriología humana sobre interacción de endometrio-blastocito. La búsqueda bibliográfica se realizó en la base de datos MEDLINE usando los términos en inglés "implantation", "endometrium" y "embryo"; además se realizó una búsqueda manual, que incluyó artículos de revistas no indexadas, libros de texto y atlas. Se consideraron criterios de inclusión y exclusión para la selección de los artículos y otros recursos bibliográficos. Entre los criterios de inclusión se consideraron estudios realizados en humanos, artículos de revisión y experimentación, publicados en los últimos 5 años. Como criterios de exclusión se consideraron artículos que utilizaran animales, estudios sobre fertilidad in vitro, patologías asociadas y artículos no relacionados al tema. Una vez completada la selección, se examinaron los textos completos, en los cuales se aplicaron nuevamente los criterios de exclusión. La búsqueda arrojó un total de 560 artículos, cuyo análisis de los títulos y resúmenes resultó en 475 trabajos excluidos, a partir de los diferentes criterios de exclusión antes descritos. Por lo tanto, se obtuvieron 85 artículos, en los cuales se realizó el análisis del texto completo. De estos artículos, se obtuvieron un total de 34 estudios y los contenidos seleccionados en esta revisión fueron: Endometrio, Interacción endometrio trofoblasto, Aposición, Adhesión y Migración-Invasión. Durante la implantación se genera una interacción entre el endometrio y el trofoblasto, con la participación de moléculas reguladoras de proliferación y diferenciación, como factores hormonales, moleculares y de expresión génica. Sin embargo, los mecanismos específicos de acción e interacción deben continuar siendo investigados, para responder interrogantes en el ámbito del crecimiento y desarrollo humano.

A successful pregnancy requires a series of interactions, mediated by hormonal, molecular and immunomodulation phenomena. One of these interactions is between the endometrium and the blastocyst, before and during the implantation process. The objective of this literature review is to complement what is described in the classic human embryology literature on endometrial-blastocyst interaction. The bibliographic search was carried out in the MEDLINE database using the terms "implantation", "endometrium" and "embryo", and a manual search was carried out, which included articles from non-indexed journals, textbooks and atlases. Inclusion and exclusion criteria were considered for the selection of articles and other bibliographic resources, including human studies, review and experimentation articles, published in the last 5 years. Articles with animals as experimental subjects, in vitro fertility studies, associated pathologies and articles not related to the subject were excluded. When the selection was completed, the complete texts were examined, in which the exclusion criteria were applied again The search yielded a total of 560 articles, whose analysis of titles and abstracts resulted in 475 excluded works, in relation to different exclusion criteria described above. Therefore, 85 articles were obtained, in which the complete text analysis was performed. From these articles, a total of 34 studies were obtained and the contents selected in this review were: Endometrium, Endometrium trophoblast, Aposition, Adhesion and Migration-Invasion. During the implantation, aninteraction between the endometrium and the trophoblast is generated, with the participation of regulatory molecules of proliferation and differentiation, such as hormonal, molecular and gene expression factors. However, the specific mechanisms of action and interaction must continue to be investigated, to answer questions in the field of human growth and development.

Evaluation of cell proliferation and endometrial thickness of bitches in different periods of diestrus

ABSTRACT This study aimed to determine the histological features of the endometrium of bitches, as well as the cell proliferation at specific moments of diestrus, 10, 20, 30, 40, 50 and 60 days post ovulation, correlating the endometrial thickness with the uterine cell proliferation and the metabolic state (weight, blood glucose and plasma cholesterol) of the animals. Therefore, the right and left uterine horns of 26 clinically healthy bitches submitted to ovariohysterectomy were histologically analyzed 10, 20, 30, 40, 50 and 60 days post ovulation. The hematoxylin-eosin and AgNOR staining techniques were performed. All parameters were evaluated by ANOVA and post-hoc Tukey test (p<0.05). The correlation between endometrial thickness and uterine cell proliferation, weight, blood glucose and plasma cholesterol of animals was observed using the Pearson method (p<0.05). In the present study, it is concluded that endometrial thickness does not differ at any of the moments analyzed in diestrus. The endometrial thickness is not influenced by hormones, weight, blood glucose or serum cholesterol of bitches in this phase of the estrous cycle. However, there is greater cell proliferation in the endometrium at day 40 compared to day 60 post ovulation under the influence of the endocrine profile.

Expression of proliferating cell nuclear antigen in the endometrium of mares during estrus and at early diestrus / Expressão do antígeno núcleo celular proliferante no endométrio de éguas durante o estro e início do diestro

Immunohistochemical expression of proliferating cell nuclear antigen (PCNA) was evaluated in the endometrium of mares during estrus and at early diestrus. Three samples were collected by endometrial biopsy from 10 mares, on estrus/ second day, in the ovulation day and seven days after the ovulation day. PCNA expression was high in luminal epithelium and low in endometrial glands on samples taken on estrus/second day and on the ovulation day (p 0.05). For samples collected on the seventh day following ovulation, the averaged PCNA immunostaining was higher in glandular epithelium (p 0.05). The study revealed that luminal epithelial cells exhibit higher proliferation during estrus and glandular epithelial cells exhibited higher proliferation during diestrus...

A expressão do antígeno núcleo celular proliferante (ANCP) foi avaliada no endométrio de éguas durante o estro e início do diestro. Em cada uma de dez éguas foram efetuadas biópsias do endométrio em três momentos dos respectivos ciclos reprodutivos: segundo dia do estro, dia da ovulação e sete dias após a ovulação. Nas amostras colhidas no segundo dia do estro e no dia da ovulação, a expressão do ANCP foi elevada no epitélio luminal e baixa nas glândulas endometriais (p 0,05). Nas amostras colhidas no sétimo dia após a ovulação, a média de ANCP imunologicamente corado foi maior no epitélio glandular (p 0,05). O estudo revelou que as células do epitélio luminal apresentaram a maior proliferação durante o estro e que as células epiteliais glandulares apresentaram a maior proliferação durante o diestro...

Characterization of Calreticulin Expression in Mouse Endometrium during Embryo Implantation

Calreticulin (CRT), a Ca2+-binding storage protein and chaperone in the endoplasmic reticulum, modulates cell adhesiveness and integrin-dependent Ca2+ signaling. However, the role of CRT during implantation remains poorly understood. In the present study, we characterized the expression of CRT mRNA and the protein in mouse endometria from pregnancy DI to D7. Real-Time PCR and in situ hybridization results showed that the levels of CRT mRNA in the endometria of pregnant mice were significantly higher than those of non-pregnant mice (P<0.05), and increased gradually from pregnancy DI to D4, reaching the máximum level on D4, followed by a plateau from D4 to D7. Using immunofluorescence histochemistry and western blot, changes of CRT expression in the endometria of pregnant mice were consistent with the expression of CRT mRNA. Furthermore, antisense CRT oligodeoxynucleotide was injected into the uterus horns of pregnant mice (D3) to investígate its effect on embryo implantation. The result showed that the number of implanted embryos markedly decreased in the side of uterine horns receiving antisense CRT oligodeoxynucleotide(í><0.05). These findings suggest that CRT may play an important role in embryo implantation in mice.

Estudo comparativo de éguas repetidoras ou não de cio através da avaliação histológica do endométrio e das concentrações plasmáticas de progesterona / Comparative study of repeat breeds and healthy mares through endometrial histology and plasmatic progesterone concentrations

O trabalho teve como objetivo geral fazer um estudo comparativo da histologia endometrial e das concentrações plasmáticas de progesterona (P4) em éguas, repetidoras ou não de cio. A hipótese do presente estudo é que existe correlação entre o histórico de infertilidade, os achados histopatológicos e a concentração de P4 destes animais. Para tanto, foram utilizadas 36 éguas, em idade reprodutiva (3-23 anos), das raças Mangalarga Marchador e Campolina. Utilizaram-se éguas não repetidoras (n=11) como grupo controle, sendo 4 éguas doadoras e 7 receptoras; e repetidoras de cio (n=25), 15 doadoras e 10 receptoras. Tal classificação foi realizada de acordo com o histórico reprodutivo destes animais. Amostras de endométrio foram coletadas para a realização de avaliação histopatológica e amostras de sangue para a mensuração das concentrações plasmáticas de progesterona. Os fragmentos de tecido endometrial obtidos pela biópsia foram fixados no Fixador de Bouin. Posteriormente os fragmentos foram processados e incluídos em parafina. Os cortes foram corados por Hematoxilina-Eosina (HE) para exame histopatológico. As concentrações plasmáticas de P4 foram mensuradas pelo método de enzima-imunoensaio (ELISA). Não foi observada correlação entre as concentrações de P4 e a subfertilidade, sendo estas variáveis tratadas como independentes. Houve uma correlação positiva entre a idade e a subfertilidade (p<0.05), assim, quanto mais velha a égua, maior a subfertilidade. Foi observada uma correlação entre a categoria da biópsia e a subfertilidade (p<0.05), ou seja, quanto mais alterações histológicas, maiores as chances da égua ser subfértil. Contudo, nem todas as éguas classificadas na Categoria I e II levaram a gestação a termo e nem todas da Categoria III tiveram falhas na reprodução, pois, deve-se considerar que outros fatores podem influenciar na manutenção da gestação. A biópsia endometrial demonstrou ser uma técnica fácil, segura, barata e com um desconforto...

The study aimed to compare endometrial histology and plasmatic progesterone (P4) concentration of repeat breeds and healthy mares. The hypothesis was that there is a correlation between infertility and endometrial histology and P4 concentration in both groups. A total of 36 Campolina and Mangalarga Marchador mares in reproductive age (3-23 years) were used, 11 of them were healthy mares (Control group, 7 embryo recipient and 4 embryo donors), and 25 repeat breeders (10 embryo recipient and 15 embryo donors), classified as based on their reproductive history. Endometrial and blood samples were collected for respectively histological and plasma progesterone concentration evaluation. The endometrial samples obtained after biopsy were fixed in Bouin's fluid, processed, included in paraffin, and stained with Hematoxylin-Eosin (HE) for histopathological examination. Plasmatic progesterone concentrations were evaluated by enzyme immunoessay (ELISA). There was no correlation between progesterone concentration and fertility. But there was a positive correlation between age and fertility, as older mares had major tendency of subfertility than younger ones. There was also a correlation between biopsy categories and fertility, as more histological alterations were found, higher were the chances for the mares to be subfertile. However not all mares classified as Category I and II maintained pregnancy until parturition. Other factors could influence pregnancy maintenance. In the same way, not all mares in Category III were infertile. The endometrial biopsy was shown to be an easy and cheap diagnostic technique with minimal discomfort to the animals and, together with other data, to be a very important component in the investigation of mare fertility.

Expresión de azúcares endometriales y del oviducto durante el ciclo reproductivo de la coneja / Expression of endometrial and oviductal glycoproteins during the reproductive cycle of female rabbit

Antecedentes: Numerosos factores han sido implicados en el proceso de implantación, entre ellos se destaca la presencia de glicoproteínas de superficie. Se ha demostrado en ratones, entre otros, que los tipos y cantidades de azúcares de superficie varían según el período del ciclo reproductivo en el que se encuentran, lo que podría sugerir un importante papel de estas variaciones en la mayor receptividad del útero al blastocisto. Objetivos: Describimos los carbohidratos de superficie del aparato reproductor de la coneja, correlacionándolos con los cambios en sus genitales externos, y con los distintos períodos de su ciclo reproductivo. Métodos: Se usaron 15 conejas, ovuladoras coitales, en las que se identifica el período del ciclo según cambios en sus genitales externos; 5 tenían vulva blanca (poca receptividad al macho y bajo índice de embarazos), 5 tenían vulva rosa, y 5 roja (máxima receptividad al macho y alto índice de embarazos). Se estudiaron variaciones en los azúcares de superficie en el oviducto, útero distal, útero medio y cuello uterino, representados por el grado de tinción de 5 lectinas: eritrina cristagalli (ECL), dolichos biforus agglutinin (DBA), ulex europaeus aglutinin-1(UEA-1), pisum sativum agglutinin (PSA) y artocarpus integrifolia (Jacalin). Resultados: Hubo predominio del disacárido N-acetilgalactosamina alfa 1-3N-acetilgalac-tosamina (DBA) en todos los períodos y lugares del aparato reproductor, exceptuando el período de vulva roja en útero medio, donde prevalece la beta galactosa (Jacalina). Los residuos de manosa/alfa glucosa (PSA), presentan alta reacción en los períodos de vulva rosa y roja en el oviducto y útero distal. La galactosa beta 1-4 N-acetil glucosamina (ECL) y la L-fucosa (UEA-1) tienen bajo nivel de expresión en todos los sitios y períodos. Conclusión: La ausencia del disacárido N-acetilgalactosamina alfa 1-3N-acetilgalac-tosamina en el período de vulva roja y en el útero medio y la prevalencia de la beta galactosa en...

Effect of matrigel on function and morphology of human endometrial epithelial cell in vitro

The importance of extra cellular matrix [ECM] in development and function of different cells has been reported but little is known about its role in human endometrial epithelial cells. The aim of the present study was to examine effects of artificial ECM [Matrigel] and progesterone on the function and morphology of human endometrial epithelial cells in vitro. Endometrial samples were removed, with informed patients consent and Ethics Committee approval, from 17 previously fertile women undergoing total abdominal hysterectomy. The tissue was dissociated and centrifuged to provide an epithelial rich suspension which was cultured either on plastic or seeded into Matrigel to produce polarized cells and then supplemented with or without progesterone [10-6 M]. The amount of nucleic acid content of the cells in both in vitro model systems was examined by DNA, RNA extraction methods. The DNA and RNA content were later measured by spectrophotometry. The amount of total RNA in cells grown on Matrigel [23 +/- 1.5 pg/cell] was more than double that in cells grown on pl1astic [9.1 +/- 1.4 pg/cell]. Cells cultured on both in vitro model systems had RNA induced by steroid hormones, but the extent of induction was greater in cells grown on Matrigel [30 +/- 2 pg/cell] than those on plastic [12 +/- 1.9 pg/cell]. Cells cultured on Matrigel were differentiated and became polarized but cells grown on plastic proliferated to full confluency. Cells grown on Matrigel with progesterone supplementation were highly polarized, euchromatic and had greater mitochondria and accumulation of glycogen, when compared to unsupplemented cultures. These results suggest that ECM plays an important role in gene expression, polarization and differentiation of human endometrial epithelial cells in vitro. Endometrial cells grown on ECM responded to steroid hormone in a manner to that reported in endometrial cells in vivo

Predicting endometrium receptivity with parameters of spiral artery blood flow / 华中科技大学学报（医学）（英德文版）

In order To evaluate whether the parameters of spiral artery blood flow, as measured by transvaginal color Doppler, may be used to assess endometrium receptivity prior to embryo transfer (ET), a retrospective study of 94 infertile women who had undergone ART treatments with different outcomes (pregnant or nonpregnant) was done. Subendometrial blood flow was evaluated. The resistance index (RI), systolic/diastolic ratio (S/D) and pulsatility index (PI) were significantly lower in those who achieved pregnancy as compared with those who did not: 0.62+/-0.04 vs 0.68+/-0.04 (P0. 2, PI>1. , and S/D>3. , no pregnancy occurred. These data suggest that the parameters of spiral artery blood flow could be used as a new assay in predicting endometrial receptivity before ET.

Experimental models for human implantation.

An understanding of the cellular and molecular basis of blastocyst implantation in the human remains as yet a black box, however, a few experimental models using human and non-human primate species have addressed this issue. This review attempts to highlight, based on experimental evidence, the paradigm shifts in our understanding of the endocrine basis of embryo implantation, and the nature of dialogue between a growing, viable conceptus and maternal endometrial cells in the establishment of 'receptivity' for blastocyst implantation. It is being proposed that an existing inflammation paradigm of blastocyst implantation could be tested using an experimental model to compare tissue behaviour of conceptus associated endometrial cells with that occurring after induction of deciduoma in hormone-primed uterus. We anticipate that an in vitro model of blastocyst implantation using the experimental models of homotypic and heterotypic cultures of uterine epithelial and stromal fibroblast cells expressing structural and functional phenotypic responses as observed in situ may provide us with necessary clues about the temporal and spatial nature of cellular and molecular functions involving various endocrine and paracrine factors at implantation.

Evaluation of selective oestrogen receptor modulators [raloxifene] on bone mineral density, serum lipids and uterine endometrium in early postmenopausal women

This study was to evaluate the effect of the second generation selective oestrogen receptor modulator [SERMs], raloxifene, on bone mineral density, serum lipid concentrations, and endometrial thickness in 100 postmenopausal women. The women were divided into two equal groups of 50 women each, and were randomly assigned to receive 60 mg of raloxifene or placebo daily for 24 months. This study revealed that women receiving [SERMs], raloxifene had significant increases from base-line values in bone mineral density of the lumbar spine, hip, and. total body, whereas those receiving placebo had decreases in bone mineral density. Serum concentrations of total cholesterol and low-density lipoprotein cholesterol decreased in the raloxifene group, whereas serum concentrations of high-density lipoprotein cholesterol and triglycerides did not change. Endometrial thickness were comparable in the raloxifene and placebo groups at all times during the study. The proportion of women receiving raloxifene who reported hot flashes or vaginal bleeding were not different from that in women receiving placebo. Selective oestrogen receptor modulator [SERMs] Raloxifen at a dose 60mg per/day increases bone mineral density, lowers serum concentration of total and low-density lipoprotein cholesterol, while has no effect on the endometrium or the breast

Morphology of the apical surface of endometrium on 1st, 6th and 22nd days of pregnancy in rats [Transmission and scanning electron microscopic study]

Morphology of the apical surface of the luminal epithelial cells of the endometrium of the rats on the 1st, 6th and 22nd days of pregnancy was examined by transmission and scanning electron microscopes. Twenty adult female and five adult male rats were used in this study. The animals were subsequently euthanized on either the 1st, 6th and 22nd days of pregnancy [term=23 days]. Using transmission electron microscope, the microvilli covering the apical surface of the luminal epithelial cells were long and irregularly spaced on the 1st day of pregnancy. They became shorter in length, numerous fewer in number and showed pinopods on the 6th day of pregnancy. Finally, they became numerous, long and slender on the 22nd day of pregnancy. Using the scanning electron microscope, it was observed that the uterine luminal epithelium was covered with long and slender microvilli on the 1st day of pregnancy. As pregnancy advanced, they became shorter and sparsely distributed with the presence of membranous protrusions on the 6th day of pregnancy. Late in pregnancy, on the 22nd day, the microvilli became longer and more numerous but no membranous protrusions could be observed

Aspectos morfométricos do endométrio de mulheres na menacme, antes e após o uso de gestodeno e etimilestradiol / Endometrium morphometric aspects of women in menacme, before and after using a gestodene ethynilestriol association

Estudaram-se, através da microscopia eletrônica de cinco mulheres na menacme. Para tanto, foram realizadasbiopsias endometriais no décimo e no vigésimo dia do ciclo menstrual. Estas pacientes foram submetidas à trapêutica contraceptiva hormonal através do uso da associação gestodeno-etinilestradiol, nas doses de 0,075 e 0,03mg respectivamente, durante seis ciclos consecutivos de vinte e um dias, com sete dias de intervalo. No sexto ciclo foram realizadas novas biopsias, também no décimo e vigésimo dias, e, como dentre as demais amostras, antes e depois do uso da associação hormonal. Os resultados permitem concluir que, após a hormonioterapia, a morfologia das células do eptélio luminal e a das células estromais assemelham-se às encotradas na primeira fase do ciclo menstrual normal (sem homônio). Ocorrem também discreta atrofia do eptélio luminal e moderada resposta progestogênica, sem modificações deciduais. O gestodeno antagoniza os efeitos proliferates dos estrogênios sobre fibroblastos e determina o surgimento de edema estromal

Participación de los factores de crecimiento en la reproducción humana / Growth factors participation in human reproduction

Los factores de crecimiento (FC) incluyen un grupo de moléculas peptídicas, con importantes efectos tróficos, mitóticos y de diferenciación celular sobre prácticamente todos los tejidos humanos. Se hace una revisión acerca de los diferentes FC, así como de sus efectos biológicos sobre los tejidos involucrados en el proceso reproductivo humano. Del mismo modo, se comenta la importancia de los FC en el desarrollo embrionario, así como en el proceso de la implantación. Finalmente, se valora la participación de los FC en la fisiopatología del síndrome de ovarios poliquísticos y de la endometriosis, a la luz de recientes investigaciones en estos campos. Se puede apreciar la importancia que los FC tienen como mediadores de diferentes hormonas (tanto en su secreción como en sus efectos biológicos), así como en la regulación de varios procesos celulares. Queda por establecer la utilidad de estos FC en la práctica cotidiana, por las limitantes tecnológicas inherentes a su identificación y cuantificación así como por la falta de más investigaciones clínicas en humanos. Sin embargo, parece tener un interesante potencial de aplicación en el manejo de problemas de esterilidad humana, así como en las diferentes técnicas de reproducción asistida, ya se in vivo o in vitro

Los nuevos moduladores endometriales en el embarazo temprano / New endometrial modulators in early pregnancy

Se pensó por mucho tiempo que las citocinas sintetizadas por el útero y la placenta eran producidas exclusivamente por y para actuar sobre las células linfohematopoyéticas. Si bien muchas de estas citocinas modulan la fase efectora del sistema inmune, en el tracto reproductor femenino, sus principales células blanco y sitios de síntesis no son las células epiteliales uterinas, las células deciduales y el trofoblasto parecen ser la fuente principal de las citocinas. Esto sugiere dos alternativas no necesariamente exclusivas: o que estas células son extensiones que regulan al sistema inmune o que estos factores modulan el crecimiento y diferenciación de los tejidos uterinos y embrionarios. En el presente trabajo se analizan los sitios de síntesis, las células blanco y las posibles funciones de la citocinas durante la gestación temprana.

Changes in lysosomal enzyme activities in pre-ovulatory follicles and endometrium of PMSG superovulated rats

Large superovulatory doses of gonadotrophins result in reduced fertility in laboratory and large domestic animals and it has been postulated that some of the superovulated oocytes are derived from abnormal follicles wich would not ovulate under normal physiological stimuli. Follicular growth, follicular maturation and atresia, ovulation and the nidation of the fertilized oocute require intense tissue remodelation which can be accomplished only through the action of hydrolytic enzymen. We have studied the activities and sub-cellular distribution of three lysosomal ensymes (acid phosphatase, N-acetyl-ß-D-glucosaminidase and ß-glucuronidase) in the follicular fluid, granulosa and theca cells of preovulatory follicles and in the endometrial tissue of immature Wistar rats injected with 4 (control) or 40 (superovulated) IU of pregnant mare serum gonadotrophin (PMSG). Enzyme activities were from four to ten time higher in theca than in granulosa cells. This difference was particularly important in the case of ß-glucuronidase. Large preovulatory follicles tended to have higher activities of lysosomal ensymes in the free fraction of all the compartments studied. This difference was remarkable in theca cells where free enzymes could be required to help ovulation. Forty IU of PMSG induced higher activities of acid phosphatase in theca and granulosa cells than 4 IU, but in endometrial tissue this latter dose of PMSG was more efficient to induce higher activities of this enzyme. The endometrial bound fraction of N-acetyl-ß-D-glucosaminidase was almost three times higher than the free activity. This behavior was also observed in endometrial ß-glucosaminidase but only in the control rats. The results observed in follicular fluid were less homogeneous. The activities of glucosaminidase and acid phosphatase were two to three times higher in rats overstimulated with 40 IU of PMSG than int he controls rats, whereas the activities of ß-glucuronidase were lower in the superovulated rats. Our results suggest that alterations in the process of tissue remodeling required for ovulation of mature, normal oocytes and for nidation of the fertilized ovum may be important factors to explain pregnancy failure in the PMSG superovulated female

Participación del citoesqueleto en la fisiología del endometrio / Cytoskeleton participation in endometrium physiology

En el endometrio el citoesqueleto participa en todas las funciones mecánicas de la célula, en el movimiento y reacomodo de organelos y proteínas solubles y en el metabolismo en general. El epitelio endometrial por su morfología y aparente homogeneidad celular, se ha estudiado más que el estroma. Se sabe que los filamentos intermedios muestran un patrón característico típico de la clase celular. Durante la preñez y la pseudopreñez, en la región apical de las células epiteliales tanto luminales como glandulares predomina la queratina sobre la región basolateral, en tanto que la vimetina solo se encuentra en las células epiteliales luminales, y se incrementa el día de la implantación. En humanos y roedores, la desmina solo se expresa en la decidua. Se piensa que los filamentos intermedios, participan en la difusión de proteínas de membrana cambiando la polaridad. Los microfilamentos intervienen en la regulación de la forma y movilidad celular. En el epitelio luminal participan en las transformaciones de la superficie uterina, como son las microvellosidades. Al sistema de microtúbulos (MT) en el endometrio y otros órganos se le ha relacionado con la psisción y movimiento de orgánulos como son los lisosomas, mitocondrias o aparato de Golgio; además se ha demostrado que los MT también intervienen en la síntesis de DNA, ya que drogas como la colchicina impiden estos fenómenos

Cambios endometriales por inducción de hiperestimulación ovárica que afectan en el proceso de implantación embrionaria / Endometrial changes by induction of ovarian hyperstimulation, which affect embryonary implantation process

En un proceso natural, el endometrio está bajo estricto control hormonal. Los protocolos de inducción de crecimiento múltiple folicular provocan concentraciones suprafisiológicas de estradiol (E2) y alterna la relación progesterona/estradiol (P4/E2) con la concomitante disminución de la receptividad endometrial, con ello se podría explicar porque es tan baja la eficiencia en los métodos de reproducción asistida