Placenta最新文献

Placental insufficiency underlies common and clinically challenging pregnancy complications including fetal growth restriction, preeclampsia, and preterm birth. Although these disorders share impaired placental function, current clinical tools cannot reliably detect early or subtle vascular abnormalities while pregnancy is ongoing. Standard obstetric ultrasound lacks the sensitivity needed to visualize small vessel development; however, high sensitivity microvessel imaging has emerged as a promising tool that overcomes many limitations of conventional Doppler ultrasound. By leveraging high frame rate or ultrafast ultrasound, together with advanced clutter filtering techniques, these highly sensitive ultrasound methods (often referred to as ultrafast Doppler or ultrasound microvessel imaging) can detect slow blood flow within small vessels that are invisible to conventional Doppler. The microvessel imaging has demonstrated promise in various clinical applications, such as assessing tumor vasculogenesis and autoimmune diseases. Only recently has microvessel imaging been applied to the placenta. Early studies show that it can visualize patterns of villous branching and vascular density that differ between healthy and complicated pregnancies. Some work has also linked microvessel imaging findings to placental pathology after delivery, suggesting the technique may allow clinicians to detect placental injury while pregnancy is ongoing. As the placenta cannot be directly assessed during gestation, a safe, non-invasive, and repeatable imaging tool is urgently needed. Ultrasound microvessel imaging has the potential to fill this gap by enabling earlier identification of at-risk pregnancies, improving monitoring and clinical decision-making throughout gestation.

Our understanding of the structure and function of the placenta and of placental disease have been enhanced by the use of in vivo imaging technologies and rodent models of pregnancy. These technologies share similarities with those used in the clinic to assess and diagnose complications of human pregnancies, providing an easy pathway for advances in rodent imaging and the findings from rodent studies to be translated to humans. Here, we review the available in vivo imaging technologies used in rodent studies of the placenta including magnetic resonance, ultrasound, positron emission tomography, and optical techniques. We synthesize the studies that have used these techniques to investigate placental perfusion, microvascular imaging, metabolism and structure. We also discuss the benefits and limitations of the technologies and provide future directions based on gaps in the present knowledge and limitations of the techniques.

Herein, we molecularly characterize the novel human term trophoblast cell line TB/SVTERT350 and show that it meets the criteria for trophoblast identity and subtype specification. TB/SVTERT350, cultured under stemness conditions in 2D or 3D, express trophoblast progenitor markers such as E-cadherin, TEAD4 and YAP1 and develop into CGβ-producing syncytiotrophoblast and HLA-G-expressing extravillous trophoblasts in the respective differentiation media. Expanding TB/SVTERT350 organoids share structural similarities with primary trophoblast organoids and express NOTCH1 suggesting that the cell line exhibits phenotypic traits of proximal cell column trophoblasts. In summary, TB/SVTERT350 could represent a reliable model for studying mechanisms of placental growth and differentiation.

Introduction: Bacterial infections during pregnancy can endanger both mother and fetus, leading to premature rupture of membranes, chorioamnionitis, preterm birth, and neonatal sepsis. Effective antibiotic therapy must ensure sufficient exposure. Ampicillin is widely used in pregnancy, particularly against group B streptococcus (GBS) and E. coli, but its pharmacokinetics, including placental transfer, are not fully understood. This study evaluated ampicillin's transplacental transfer using an ex vivo placenta dual-side perfusion model and assessed maternal serum concentrations in pregnant women undergoing therapy.

Materials and methods: Six placentas were perfused with 50 or 100 mg/L ampicillin. Ampicillin concentrations were assessed both in the maternal and fetal circuits every 30 min during a period of 4 h. Additionally, maternal serum samples from six pregnant women (gestational age: 24 + 4 to 33 + 0) receiving 2 g ampicillin intravenously were analyzed every 30 min up to 4 h post-administration. Antibiotic concentrations were determined using LC-MS.

Results: Concentrations determined in the maternal perfusion circuit were 33.4 ± 15.9 and 41.2 ± 5.8 mg/L, as well as 15.4 ± 4.5 and 25.3 ± 19.9 mg/L in the fetal circuit. The transfer rate was about 25 % after 4 h of perfusion. Maternal serum concentrations at 30 min reached 54.1 ± 6.4 mg/L and declined to 2.3 ± 1.6 mg/L at 4 h.

Discussion: This study using an ex vivo placenta perfusion model, revealed only moderate transplacental transfer of ampicillin. This finding, in the context of the retrieved serum concentrations, suggests that adjusted dosing may be required in severe conditions to optimize drug exposure, emphasizing the need for further pharmacokinetic research in pregnancy.

Trophoblast cells line the surface of placental villi, facilitating the exchange of nutrients, gases, and wastes between the maternal and fetal circulations. The fusion of cytotrophoblast (CTB) cells into the surrounding multinucleated syncytiotrophoblast (STB), is accompanied by a shift in cellular ultrastructure (subcellular architecture). Mitochondria undergo a remarkable decrease in size and alteration in morphology following trophoblast differentiation, and have thus been the subject of investigations due to their crucial role in producing energy for placental development. Observing this shift in structure has relied on the use of electron microscopy, which has offered insights into underlying mitochondrial functions. Since the initial use of electron microscopy to study villous trophoblasts in the 1950s, novel techniques have emerged that have the capacity to interrogate placental ultrastructure with unprecedented resolution. This review discusses the evolution of electron microscopy techniques to study the placenta over the last 70 years. Moreover, we discuss emerging methods for resolving 3D organelle structure within the placenta, which offer more physiologically pertinent information and context for complex topologies. Further, we discuss advanced methods of cryo-electron tomography (cryo-ET) that present the placental field with an exciting opportunity to determine the complex relationship between mitochondrial architecture and protein structure in the human placenta. By specifically focusing on mitochondrial imaging, we showcase the capacity for volume electron microscopy and cryo-ET to reveal the role of organelle structure in placental development.