RESUMEN
Disequilibrium of hormonal intercommunication between the maternal brain and the developing fetal-placental unit increases morbidity and mortality risk for the mother-baby dyad. As a novel yet temporary endocrine organ, the placenta serves as a physical and immunologic barrier that facilitates exchange of nutrients and elimination of fetal waste. Steroid and peptide-based hormones secreted by the placenta and other neuroendocrine organs induce adaptations in maternal physiology accommodating fetal growth and development and enabling lactation postpartum. Human placental growth hormone, a peptide hormone continuously secreted at increasing concentrations throughout pregnancy, is a primary determinant of maternal insulin resistance and gestational diabetes.
Asunto(s)
Diabetes Gestacional , Placenta , Humanos , Embarazo , Femenino , Placenta/fisiología , Resistencia a la Insulina/fisiología , Complicaciones del EmbarazoRESUMEN
In Brief: The mechanisms that determine the length of pregnancy remain undetermined. Here, we review what has been previously published on the topic and incorporate new data to describe a molecular model in which placental stress and fetal signaling ultimately lead to labor onset in uncomplicated pregnancies. Abstract: The mechanisms that govern the length of human pregnancy have not been determined, while preterm birth remains the leading cause of death and disability in newborns worldwide. Here, we review recent data to generate a novel hypothesis about how the pregnancy clock may function to initiate human labor in uncomplicated pregnancies. In this model, placental stress induced by the growing fetus drives placental production of NFKB, which is then activated by exosomes containing platelet-activating factor and complement 4-binding protein-A from the mature fetus, to drive pro-labor genes in the placenta. A better understanding of the clock that triggers labor may lead to new, more effective therapies to prevent spontaneous preterm birth.
Asunto(s)
Placenta , Humanos , Femenino , Embarazo , Placenta/metabolismo , Placenta/fisiología , Relojes Biológicos , Nacimiento Prematuro/metabolismo , Inicio del Trabajo de Parto/fisiologíaRESUMEN
The human placenta serves as a vital barrier between the mother and the developing fetus during pregnancy. A defect in the early development of the placenta is associated with severe pregnancy disorders. Despite its complex development, various molecular processes control placental development, and the specialization of trophoblast cells is still not fully understood. One primary obstacle is the lack of suitable cell model systems. Traditional two-dimensional (2D) cell cultures fail to mimic in vivo conditions and do not capture the intricate intercellular interactions vital for studying placental development. However, three-dimensional (3D) organoid models derived from stem cells that replicate natural cell organization and architecture have greatly improved our understanding of trophoblast behavior and its medicinal applications. Organoids with relevant phenotypes provide a valuable platform to model both placental physiology and pathology, including the modeling of placental disorders. They hold great promise for personalized medicine, improved diagnostics, and the evaluation of pharmaceutical drug efficacy and safety. This article provides a concise overview of trophoblast stem cells, trophoblast invasion, and the evolving role of organoids in gynecology.
Asunto(s)
Organoides , Células Madre , Trofoblastos , Humanos , Trofoblastos/fisiología , Organoides/fisiología , Femenino , Embarazo , Células Madre/fisiología , Placenta/citología , Placenta/fisiología , Placenta/patología , Placentación/fisiologíaRESUMEN
Placental abnormalities more frequently occur during pregnancy of somatic cell clones and may lead to pregnancy loss or dystocia. Adventitious placentation, or diffuse semi-placenta, is determined by the development of areas of accessory placentation between the cotyledons due to the abnormal growth of placentomes.After a full-term pregnancy, a 3-year-old Jersey heifer was referred for dystocia which resulted in the delivery of a dead calf. The cause of dystocia was found to be foetal malposition, while the placenta was physiologically expelled after dystocia resolution.Grossly, cotyledons appeared reduced in size and number in one placental horn, while the surface of the other horn was covered with microplacentomes. Numerous villous structures without trophoblastic coating were highlighted after histopathology. The dominant sign was an inflammatory reaction. The findings were consistent with inter-cotyledonal placentitis, which led to adventitial placentation.Diffuse semi-placenta compensates for the inadequate development of placentomes and may occur as a congenital or acquired defect. The outcome depends on its severity: in the worst scenario, pregnancy may not proceed beyond midterm and may be complicated by hydrallantois. In the case under examination, the dimensions of the cotyledons (from 2 to 10 cm) allowed for the natural course of pregnancy.
Asunto(s)
Enfermedades de los Bovinos , Distocia , Bovinos , Embarazo , Animales , Femenino , Placenta/patología , Placenta/fisiología , Placentación , Pelvis , Distocia/veterinaria , Enfermedades de los Bovinos/diagnóstico , Enfermedades de los Bovinos/patologíaRESUMEN
BACKGROUND: Prenatal exercise improves birth outcomes, but research into exercise dose-response effects is limited. METHODS: This study is a retrospective, secondary analysis of pooled data from three blinded, prospective, randomized controlled trials. Prenatal exercise frequency, intensity, type, time, and volume (FITT-V) were assessed in supervised sessions throughout pregnancy. Gestational age (GA), neonatal resting heart rate (rHR), morphometrics (body circumferences, weight-to-length and ponderal index) Apgar and reflex scores, and placental measures were obtained at birth. Stepwise regressions and Pearson correlations determined associations between FITT-V and birth outcomes. RESULTS: Prenatal exercise frequency reduces ponderal index (R2 = 0.15, F = 2.76, p = .05) and increased total number of reflexes present at birth (R2 = 0.24, F = 7.89, p < .001), while exercise intensity was related to greater gestational age and birth length (R2 = 0.08, F = 3.14; R2 = 0.12, F = 3.86, respectively; both p = .04); exercise weekly volume was associated with shorter hospital stay (R2 = 0.24, F = 4.73, p = .01). Furthermore, exercise type was associated with placenta size (R2 = 0.47, F = 3.51, p = .01). CONCLUSIONS: Prenatal exercise is positively related to birth and placental outcomes in a dose-dependent manner.
Asunto(s)
Ejercicio Físico , Salud Materna , Parto , Placenta , Resultado del Embarazo , Humanos , Femenino , Embarazo , Recién Nacido , Adulto , Parto/fisiología , Ejercicio Físico/clasificación , Ejercicio Físico/fisiología , Estudios Retrospectivos , Placenta/anatomía & histología , Placenta/fisiología , Frecuencia Cardíaca/fisiología , Edad Gestacional , Puntaje de Apgar , Tiempo de Internación , Peso al NacerRESUMEN
OBJECTIVES: Antenatal exercise is associated with placental morphological alterations, however research in this area is limited. Given the emphasis on the beneficial effects of antenatal exercise, it is important to understand its effect on placental function and the relationship to foetal development. The aim of this study was to investigate the association between physical activity, sitting time, and placental outcomes measured during gestation. DESIGN: Prospective cohort study. METHODS: Pregnant women in the Queensland Family Cohort study self-reported physical activity at 24 and 36â¯weeks of gestation (nâ¯=â¯203) and were categorised into physical activity volume groups of nil-low (0-<500 metabolic equivalent of task·minutes/week), moderate (500-<1000 metabolic equivalent of task·minutes/week), or high-volume activity (≥1000 metabolic equivalent of task·minutes/week). Participants reported average daily sitting time, whereby excessive sitting time was considered as ≥8h/day. Placental stiffness, thickness, and uteroplacental blood flow resistance were measured by ultrasound imaging at each timepoint. RESULTS: Physical activity volume was not associated with changes to placental morphometrics or uteroplacental blood flow resistance at 24 or 36â¯weeks of gestation. Excessive sitting time at 36 weeks was associated with greater placental stiffness (pâ¯=â¯0.046), and a lower umbilical artery pulsatility index (pâ¯=â¯0.001). CONCLUSIONS: Placental tissue stiffness and umbilical artery resistance were altered in late gestation with higher maternal sitting time but not with physical activity volume. Overall, excessive sitting time may be a risk for suboptimal placental function and could be an important focus for antenatal care.
Asunto(s)
Ejercicio Físico , Placenta , Sedestación , Humanos , Femenino , Embarazo , Ejercicio Físico/fisiología , Placenta/anatomía & histología , Placenta/irrigación sanguínea , Placenta/fisiología , Adulto , Estudios Prospectivos , Queensland , Arterias Umbilicales/diagnóstico por imagen , Arterias Umbilicales/fisiología , Adulto Joven , Conducta SedentariaRESUMEN
Although the central role of adequate blood flow and oxygen delivery is known, the lack of optimized imaging modalities to study placental structure has impeded our understanding of its vascular function. Magnetic resonance imaging is increasingly being applied in this field, but gaps in knowledge remain, and further methodological developments are needed. In particular, the ability to distinguish maternal from fetal placental perfusion and the understanding of how individual placental lobules are functioning are lacking. The potential clinical benefits of developing noninvasive tools for the in vivo assessment of blood flow and oxygenation, two key determinants of placental function, are tremendous. Here, we summarize a number of structural and functional magnetic resonance imaging techniques that have been developed and applied in animal models and studies of human pregnancy over the past decade. We discuss the potential applications and limitations of these approaches. Their combination provides a novel source of contrast to allow analysis of placental structure and function at the level of the lobule. We outline the physiological mechanisms of placental T2 and T2* decay and devise a model of how tissue composition affects the observed relaxation properties. We apply this modeling to longitudinal magnetic resonance imaging data obtained from a preclinical pregnant nonhuman primate model to provide initial proof-of-concept data for this methodology, which quantifies oxygen transfer and placental structure across and between lobules. This method has the potential to improve our understanding and clinical management of placental insufficiency once validation in a larger nonhuman primate cohort is complete.
Asunto(s)
Imagen por Resonancia Magnética , Placenta , Animales , Femenino , Embarazo , Imagen por Resonancia Magnética/métodos , Placenta/diagnóstico por imagen , Placenta/fisiología , Primates , Modelos AnimalesRESUMEN
Research on the biology of fetal-maternal barriers has been limited by access to physiologically relevant cells, including trophoblast cells. In this study, we describe the development of a human term placenta-derived cytotrophoblast immortalized cell line (hPTCCTB) derived from the basal plate. Human-term placenta-derived cytotrophoblast immortalized cell line cells are comparable to their primary cells of origin in terms of morphology, marker expression, and functional responses. We demonstrate that these can transform into syncytiotrophoblast and extravillous trophoblasts. We also compared the hPTCCTB cells to immortalized chorionic trophoblasts (hFM-CTC), trophoblasts of the chorionic plate, and BeWo cells, choriocarcinoma cell lines of conventional use. Human-term placenta-derived cytotrophoblast immortalized cell line and hFM-CTCs displayed more similarity to each other than to BeWos, but these differ in syncytialization ability. Overall, this study (1) demonstrates that the immortalized hPTCCTB generated are cells of higher physiological relevance and (2) provides a look into the distinction between the spatially distinct placental and fetal barrier trophoblasts cells, hPTCCTB and hFM-CTC, respectively.
Asunto(s)
Placenta , Trofoblastos , Humanos , Trofoblastos/citología , Trofoblastos/fisiología , Femenino , Embarazo , Placenta/citología , Placenta/fisiología , Línea CelularRESUMEN
La membrana amniótica (MA), ubicada en el lado interno de la placenta fetal, ha sido objeto de múltiples investigaciones para intentar dilucidar su papel embriológico y su potencial celular terapéutico. Actualmente las limitaciones del estudio en fetos humanos hacen que parte de su funcionamiento sea una incógnita, sin embargo algunos estudios clínicos y básicos nos dan luz sobre su papel en la médica moderna. Se realizó una revisión bibliográfica de la literatura desde 1960 hasta 2022, empleando bases de datos como PubMed, SciELO y Scopus, siendo incluidos un total de 50 artículos y dos textos de embriología. El objetivo de esta revisión narrativa fue sintetizar la información sobre la angiogénesis y su importancia clínica. La información recopilada permitió evidenciar que las propiedades de curación de la piel del feto se deben a factores intrínsecos del feto, y a que las células epiteliales amnióticas humanas poseen una diferenciación similar a las células madre embrionarias, con la capacidad de diferenciación similar al de las células mesenquimales, resaltando su importancia clínica por sus características regenerativas. En conclusión, el desarrollo embrionario humano sigue siendo relativamente inexplicable, pero su conocimiento ha permitido grandes avances, que podrían ser útiles en terapias de regeneración, reparación de tejidos y órganos lesionados.
The amniotic membrane, located on the inner side of the fetal placenta, has been the subject of multiple investigations to try to elucidate its embryological role and its therapeutic cellular potential. Currently, the limitations of the study in human fetuses mean that part of its functioning is unknown, however, some clinical and basic studies shed light on its role in modern medicine. A bibliographic review of the literature was carried out from 1960 to 2022, using databases such as PubMed, SciELO and Scopus, including a total of 50 articles and two embryology texts. The objective of this narrative review was to synthesize information on angiogenesis and its clinical importance. The information collected made it possible to show that the healing properties of the fetal skin are due to intrinsic factors of the fetus, and that human amniotic epithelial cells have a differentiation similar to embryonic stem cells, with the differentiation capacity similar to that of mesenchymal cells, highlighting their clinical importance due to their regenerative characteristics. In conclusion, human embryonic development remains relatively inexplicable, but its knowledge has allowed great advances, which could be useful in regeneration therapies, repair of injured tissues and organs.
Asunto(s)
Humanos , Femenino , Embriología/educación , Placenta/fisiología , Epidemiología Descriptiva , Amnios/citologíaRESUMEN
ABSTRACT Objective Measure umbilical cord pulsatility time and evaluate correlation/association with maternal and neonatal characteristics. Method Cross-sectional study, with 76 binomials, carried out in 2017, in a maternity hospital in Alagoas. Analysis with Pearson or Spearman correlation test and Mann-Whitney or Kruskal-Wallis test. Results Sixty-two parturients and their newborns participated of the research. The women had a gestational age ≥ 37 weeks, natural cephalic birth, without distortions. The newborns had average weight of 3326.29g, mostly male. The umbilical cord pulsatility time was 285.48s. There is a correlation between umbilical cord pulsatility time and placental delivery time (p<0.001). Other correlations/associations were not significant. Conclusion It suggested using a correlation between pulsatility time and placental delivery time in clinical decision making for good practices in childbirth assistance.
RESUMEN Objetivo Medir tiempo de pulsatilidad del cordón umbilical y evaluar la correlación/asociación con las características maternas y neonatales. Método Estudio transversal, con 76 pares, realizado en 2017, en maternidad en Alagoas. Análisis con la prueba de correlación de Pearson o Spearman y la prueba de Mann-Whitney o Kruskal-Wallis. Resultados Sesenta y dos mujeres en trabajo de parto y sus recién nacidos participaron. Las mujeres tenían edad gestacional ≥ 37 semanas, parto cefálico normal, sin distorsiones. Los recién nacidos tenían peso promedio de 3326.29g, la mayoría de ellos varones. Tiempo de pulsatilidad del cordón umbilical fue de 285.48s. Había correlación entre el tiempo de pulsatilidad del cordón umbilical y el momento del parto placentario (p<0,001). Otras correlaciones/asociaciones no fueron significativas. Conclusión Sugiere una correlación entre el tiempo de pulsatilidad y el tiempo de parto placentario para las buenas prácticas en la atención del parto.
RESUMO Objetivo Mensurar tempo de pulsatilidade do cordão umbilical e avaliar correlação/associação com característica maternas e neonatais. Método Estudo transversal, com 76 binômios, realizado no ano de 2017, em maternidade de Alagoas. Análise com teste de correlação de Pearson ou Spearman e teste de Mann-Whitney ou Kruskal-Wallis. Resultados Sessenta e duas parturientes e seus recém-nascidos participaram da pesquisa. As mulheres tinham idade gestacional ≥ 37 semanas, parto normal cefálico, sem distorcias. Os recém-nascidos tinham peso médio de 3326,29g, maioria do sexo masculino. O tempo de pulsatilidade do cordão umbilical foi 285,48s. Há correlação entre tempo de pulsatilidade do cordão umbilical e tempo de dequitação da placenta (p<0,001). Demais correlações/associações não foram significativas. Conclusão Sugere-se o uso correlação entre tempo de pulsatilidade e tempo de dequitação da placenta na tomada de decisão clínica para boas práticas na assistência ao parto.
Asunto(s)
Humanos , Femenino , Embarazo , Placenta/fisiología , Cordón Umbilical/embriología , Parto Normal , Enfermería Obstétrica , Brasil , Epidemiología Descriptiva , Estudios Transversales , MaternidadesRESUMEN
Placentas from pregnant cows with different gestation periods were used. Placental fragments of all groups were processed and evaluated by transmission electron microscopy. After fragment analysis, bovine placenta was observed to be epitheliochorial type in early pregnancy, becoming progressively sinepiteliocorial at the beginning of the second trimester. There are no ultrastructural evidences of inflammation in the region of caruncles throughout gestation, despite the invasion of caruncle proper lamina by trophoblast cells. However, throughout pregnancy and especially at the end, there were evident signs of cell degeneration in both trophoblast and the uterine epithelium. The active trophoblast cells intensely phagocytize cellular debris. There are complex interdigitations between the surface of the trophoblast and the uterine epithelium, which is related to the increase of the exchange surface between mother and fetus. At the end of pregnancy, interdigitations disappear, favoring the detachment and expulsion of the placenta after birth.(AU)
Foram utilizadas placentas de vacas abatidas em frigorífico com diversos tempos gestacionais. Fragmentos de placentomo de todos os grupos foram processados e avaliados em microscopia eletrônica de transmissão. Após análise dos fragmentos, observou-se que a placenta bovina é do tipo epiteliocorial no início da gestação, tornando-se sinepiteliocorial progressivamente a partir do início do segundo mês de gestação. Não existem evidências ultraestruturais de inflamação na região das carúnculas durante toda a gestação, apesar da invasão da lâmina própria caruncular por células trofoblásticas. No entanto, durante toda a gestação e em especial ao seu final, foram observados sinais evidentes de degeneração celular, tanto do trofoblasto como do epitélio uterino. As células trofoblásticas ativas fagocitam intensamente os debris celulares originados dessas degenerações. Existem complexas interdigitações entre a superfície do trofoblasto e do epitélio uterino, o que estaria relacionado com o aumento da superfície de troca entre mãe e feto. Ao final da gestação, praticamente desaparecem essas interdigitações, favorecendo o descolamento e a expulsão da placenta após o parto.(AU)
Asunto(s)
Animales , Femenino , Embarazo , Bovinos , Intercambio Materno-Fetal/fisiología , Placenta/fisiología , Placenta/ultraestructura , Microscopía Electrónica de Transmisión/veterinariaRESUMEN
A gestação é um estado fisiológico que exige adaptações imunológicas para que transcorra normalmente. Nesse período a mãe e o feto apresentam uma relação imunológica, ou seja, a interface materno fetal. A enzima indoleamina 2,3 dioxigenase (IDO) desempenha um papel importante na tolerância materno fetal, por ser responsável pela metabolização do triptofano, impedindo por diversas vias a proliferação principalmente de linfócitos TCD8. Diversos tipos celulares estão presentes na interface materno fetal e vários deles podem expressar a IDO. Os leucócitos com perfil Th1 produzem uma citocina conhecida: o interferon γ que estimula a expressão da IDO em vários tipos celulares. Os linfócitos são divididos em subpopulações de acordo com sua função e fenótipo. Seus tipos incluem linfócitos T, linfócitos B e as células natural killer (NK). Hormônios também atuam nesse processo a progesterona que exerce função determinante sobre a resposta imunológica materna podendo alterar o prognóstico gestacional e o estrógeno essencial para a tolerância materno fetal e manutenção da prenhez. Dessa maneira este trabalho tem por objetivo principal identificar os linfócitos presentes na placenta bovina em cultivo que expressam IDO (linfócitos T, linfócitos B e células NK), frente a estimulação por progesterona, estrógeno e interferon γ nas diversas fases gestacionais utilizando a citometria de fluxo. Segundo os resultados no período de 67,5 a 77, 5 dias com a adição de interferon γ a expressão da enzima IDO aumentou discretamente nos linfócitos TCD3, TCD4, e diferente dos linfócitos T CD8 apresentaram uma elevada expressão da enzima (4,48 ± 2,12 - 8,65± 4,91)....
Pregnancy is a physiological state that requires immune adaptation in order to be successfully carried on. During this period, mother and fetus establish an immune tolerance status at the maternal fetal interface. Indoleamine 2,3-dioxygenase (IDO) plays an important role in maternal-fetal tolerance by metabolizing tryptophan, impairs by several pathways, mainly T CD8 cells proliferation. Several cell types are present in the maternal fetal interface and several of them can express IDO. Leucocytes with Th1 produce a cytokine known as interferon γ that stimulates the expression of IDO in several cell types. Lymphocytes are divided into sub-populations according to their function and phenotype: T lymphocytes, B lymphocytes and natural killer cells (NK). Hormones also involved in this process where progesterone exerts decisive role on maternal immune response that may change gestational outcome and estrogen is essential for fetal maternal tolerance and maintenance of pregnancy. Therefore, the main objective of this study was to identify lymphocytes in the bovine placental cell culture that are sensitive to progesterone, estrogen and interferon γ, IDO expression in various gestational stages using flow cytometry. According to the results in the gestational period from 67.5 to 77.5 days with the addition of interferon γ expression IDO was slightly increased in TCD3 lymphocytes, CD4, and differently from the other T cells CD8 displayed an higher expression of the enzyme (4.48±2.12 to 8.65±4.91)...
Asunto(s)
Animales , Femenino , Embarazo , Bovinos , Inmunofenotipificación/veterinaria , /análisis , Linfocitos/clasificación , Linfocitos/inmunología , Placenta , Placenta/fisiología , Tolerancia Inmunológica/fisiología , Linfocitos B , Estrógenos/análisis , Interferón gamma/análisis , Células Asesinas Naturales , Progesterona/análisis , Linfocitos TRESUMEN
OBJECTIVE: To describe a series of studies conducted which investigated maternal nutrition and its effect on birth outcome. METHODS: Seven hundred and twelve women attending their first antenatal clinic visit at the University Hospital of the West Indies were invited to join a prospective study. The women were followed throughout their pregnancies and seen at 14, 17, 20, 25, 30 and 35 weeks gestation. At these visits, the mother's weight, height and triceps skinfold thickness were measured. Abdominal ultrasound was performed to determine placental and fetal growth. Birth and placental weight, head, chest, mid-upper arm and abdominal circumference, crown-rump and crown-heel length were measured. After delivery, mothers and their children were recruited into a longitudinal study of postnatal growth in which blood pressure was measured annually initially and then half yearly from age one year. RESULTS: The interrelationship of first trimester maternal weight, subsequent weight gain in pregnancy, placental weight in early pregnancy and fetal growth were reported. Placental volume was shown to be an earlier predictor of infant size, and placental volume and intrauterine life on birthweight and blood pressure in childhood showed a relationship to blood pressure at two to three years old. The ultrasound derived fetal growth curves for a Jamaican population was created. CONCLUSION: Maternal nutritional status has an important effect on fetal size and birthweight and fetal size has an effect on blood pressure in childhood, suggesting that the initiating events in programming of blood pressure occur early in pregnancy.
OBJETIVO: Describir una serie de estudios encaminados a investigar la nutrición materna y su efecto en el resultado del embarazo. MÉTODOS: Setecientos doce mujeres que asistían a su primera visita de la clínica prenatal en el Hospital Universitario de West Indies, fueron invitados a sumarse a un estudio prospectivo. Se realizó un seguimiento de las mujeres a lo largo de sus embarazos, con visitas en las semanas 14, 17, 20, 25, 30 y 35 de gestación. En estas visitas, se midió el peso, la altura y el grosor del pliegue cutáneo del tríceps. Se les realizó un ultrasonido abdominal con el fin de determinar el crecimiento placentario y fetal. Se midieron el peso al nacer y el peso de la placenta, la cabeza, el pecho, circunferencia del abdomen y la parte media superior del brazo, las longitudes céfalo-caudal y coronilla-talón. Después del parto, las madres y sus niños fueron reclutados para un estudio longitudinal de crecimiento postnatal en el que la presión sanguínea se mide anualmente, inicialmente y luego a mitad de año desde el primer año de edad. RESULTADOS: Se reportó la interrelación del peso materno en el primer semestre, el subsiguiente aumento de peso en el embarazo, el peso de la placenta al inicio del embarazo, y el crecimiento fetal. El volumen de la placenta resultó ser un predictor temprano del tamaño del infante, y el volumen de la placenta y la vida intrauterina en el peso al nacer, y la presión sanguínea en la infancia mostró una relación con la presión sanguínea a los dos hasta los tres años de edad. CONCLUSIÓN: El estado de la nutrición materna tiene un efecto importante en el tamaño del feto y el peso al nacer, y el tamaño del feto tiene un efecto sobre la presión sanguínea en la infancia, lo cual sugiere que los procesos que inician la programación de la presión sanguínea ocurren en una etapa temprana del embarazo.
Asunto(s)
Adolescente , Adulto , Femenino , Humanos , Embarazo , Adulto Joven , Desarrollo Fetal/fisiología , Feto/fisiología , Resultado del Embarazo , Bienestar Materno , Estado Nutricional , Placenta/fisiología , Ultrasonografía Prenatal , Aumento de PesoRESUMEN
A descrição do transporte placentário envolve informações sobre mecanismos, propriedades e regulação genética das substâncias moleculares. Nas trocas materno-fetais faz-se necessário atravessar uma camada de células do sinciotrofoblasto (microvilosidades e camada basal da membrana plasmática)bem como o tecido conectivo e o endotélio capilar fetal. Assim, a troca sanguínea entre as duas circulações materna e fetal por meio do espaço interviloso e dos capilares vilosos ocorre através da barreira placentária. Os tipos de transporte de substâncias através da placenta são variáveis. Diversos mecanismos de transporte do sódio têm sido demonstrados, embora o transporte ativo de K+ ainda não esteja bem esclarecido no ser humano. O transporte placentário de cálcio, magnésio e fósforo acontece por transporte ativo, o qual aumenta no último trimestre de gestação, e coincide com o aumento da mineralização do esqueleto fetal. Desta forma, o entendimento das relações entre as diversas substâncias do organismo e o transporte através da placenta se faz necessário para melhor compreender a nutrição fetal e a patogênese de algumas doenças intra-útero.
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Femenino , Embarazo , Transporte Biológico Activo , Electrólitos , Intercambio Materno-Fetal , Circulación Placentaria , Placenta/fisiología , Placenta/metabolismoRESUMEN
The Maxi-chloride channel was the first ion channel described by electrophysiological methods in placenta. Because it is difficult to access a complex epithelium such as the placenta for electrophysiological procedures, the studies of ion channels from placental membranes have been performed only very recently. It was only in 1993 that a direct demonstration of a high-conductance chloride channel in apical membranes of intact trophoblastic epithelium was mentioned, and two years later, the description of this channel was reported from purified placental apical membranes reconstituted into artificial lipid membranes suitable for patch-clamp recordings. This brief review comments on the work done with regard to the electrophysiological characterization and regulation of the large-conductance or "Maxi" chloride channel and its contribution to the development of a cellular model for syncytiotrophoblast ion transport.
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Femenino , Humanos , Embarazo , Canales de Cloruro/metabolismo , Potenciales de la Membrana/fisiología , Placenta/metabolismo , Trofoblastos/metabolismo , Electrofisiología , Transporte Iónico , Técnicas de Placa-Clamp , Placenta/fisiologíaAsunto(s)
Humanos , Embarazo , Femenino , Anestésicos/efectos adversos , Circulación Placentaria , Feto/efectos de los fármacos , Feto/fisiología , Placenta/fisiología , Embarazo/efectos de los fármacos , Embarazo/metabolismo , Antipsicóticos/farmacocinética , Anestésicos Locales/farmacocinética , Anestésicos por Inhalación/farmacocinética , Antagonistas de Narcóticos/farmacocinética , Anticonvulsivantes/farmacocinética , Benzodiazepinas/farmacocinética , Bupivacaína/farmacocinética , Bloqueadores de los Canales de Calcio/farmacocinética , Epinefrina/farmacocinética , Antagonistas de los Receptores H2 de la Histamina/farmacocinética , Ketamina/farmacocinética , Lidocaína/farmacocinética , Meperidina/farmacocinética , Metoclopramida/farmacocinética , Fármacos Neuromusculares no Despolarizantes/farmacocinética , Procaína/farmacocinética , Progesterona/farmacocinética , Propofol/farmacocinética , Tiopental/farmacocinéticaAsunto(s)
Humanos , Femenino , Embarazo , Desarrollo Fetal , Intercambio Materno-Fetal , Placenta/enzimología , Placenta/fisiologíaRESUMEN
Este artigo faz uma revisao da estrutura placentaria, seus mecanismos fisiologicos de transporte, e o reflexo sobre o feto da passagem de algumas substancias capazes de determinar alteracoes no seu bem estar e desenvolvimento.
Asunto(s)
Humanos , Femenino , Embarazo , Permeabilidad , Placenta/fisiología , Factores de Riesgo , Mortalidad Infantil , Exposición Materna , Teratógenos/toxicidadRESUMEN
A placenta e responsavel pela nutricao e oxigenacao adequada do feto durante a vida intra-uterina. A funcao placentaria pode ser avaliada pela dopplervelocimetria das circulacoes utero-placentaria, feto-placentaria e fetal. Nas gestacoes de alto risco para insuficiencia placentaria, a avaliacao dopplervelocimetrica e de fundamental importancia, principalmente, na orientacao da conduta obstetrica
Asunto(s)
Humanos , Femenino , Enfermedades Placentarias/diagnóstico , Insuficiencia Placentaria/diagnóstico , Ultrasonografía Doppler , Desarrollo Fetal , Placentación , Placenta/fisiología , Placenta/fisiopatología , Embarazo de Alto RiesgoRESUMEN
Com a finalidade de avaliar a influência do meio ambiente materno nos níveis sangüíneos dos hormônios gonadotrófico (HCG) e lactogêncio plancentário (HPL) no início da gestaçäo, foram estudadas 326 gestantes de primeiro trimestre. O HCG e o HPL foram dosados e padronizados para o dia 70 da gestaçäo para permitir a comparaçäo dos resultados. O meio ambiente materno foi avaliado através das dosagens de hemoglobina (Hb), hematócrito (Ht), volume corpuscular médio (VCM), contagem de glóbulos vermelhos (CGV), ferro (Fe), ferritina (Fer), capacidade total de ligaçäo do ferro (TIBC) e índice de massa corpórea (IMC). Concluiu-se que existe uma correlaçäo inversa estatisticamente significativa entre o IMC, Hb e Ht e os níveis sangüíneos maternos do HCG