Placental Nanoparticle Uptake-On-a-Chip: The Impact of Trophoblast Syncytialization and Shear Stress.

The placenta is a dynamic and complex organ that plays an essential role in the health and development of the fetus. Placental disorders can affect the health of both the mother and the fetus. There is currently an unmet clinical need to develop nanoparticle-based therapies to target and treat placental disorders. However, little is known about the interaction of nanoparticles (NPs) with the human placenta under biomimetic conditions. Specifically, the impact of shear stress exerted on the trophoblasts (placental epithelial cells) by the maternal blood flow, the gradual fusion of the trophoblasts along the gestation period (syncytialization), and the impact of microvilli formation on the cell uptake of NPs is not known. To this end, we designed dynamic placenta-on-a-chip models using BeWo cells to recapitulate the micro-physiological environment, and we induced different degrees of syncytialization via chemical induction with forskolin. We characterized the degree of syncytialization quantitatively by measuring beta human chorionic gonadotropin (ß-hCG) secretion, as well as qualitatively by immunostaining the tight junction protein, ZO-1, and counter nuclear staining. We also characterized microvilli formation under static and dynamic conditions via F-actin staining. We used these models to measure the cell uptake of chondroitin sulfate a binding protein (CSA) conjugated and control liposomes using confocal microscopy, followed by image analysis. Interestingly, exposure of the cells to a dynamic flow of media intrinsically induced syncytialization and microvilli formation compared to static controls. Under dynamic conditions, BeWo cells produced more ß-hCG in conditions that increased the cell exposure time to forskolin (p < 0.005). Our cell uptake results clearly show a combined effect of the exerted shear stress and forskolin treatment on the cell uptake of liposomes as uptake increased in forskolin exposed conditions (p < 0.05). Overall, the difference in the extent of cell uptake of liposomes among the different conditions clearly displays a need for the development of dynamic models of the placenta that consider the changes in the placental cell phenotype along the gestation period, including syncytialization, microvilli formation, and the expression of different transport and uptake receptors. Knowledge generated from this work will inform future research aiming at developing drug delivery systems targeting the placenta.

Thoracoscopic repair in congenital diaphragmatic hernia: patching is safe and reduces the recurrence rate.

PURPOSE: Congenital diaphragmatic hernia (CDH) has traditionally been repaired via a laparotomy. More and more reports on thoracoscopic repair are being published. The aim of this study was to evaluate our series of thoracoscopic CDH repair and compare this group to an open repair group treated during the same period in the same institute. PATIENTS AND METHODS: Between June 2006 and December 2008, 49 children with posterolateral CDH were admitted, of whom 23 (47%) were operated thoracoscopically and 23 (47%) using an open repair, depending on the discretion of the attending surgeon and the clinical condition of the patient. Three patients (6%) with CDH were not treated because of associated anomalies (twice Cornelia de Lange syndrome and once hypoplastic left heart syndrome). Six thoracoscopic operations (26%) were converted to open surgery. Nine defects (39%) were closed thoracoscopically without a patch. In 8 (35%) patients, a patch was used. We used a patch in 20 open procedures (87%). RESULTS: Three (33%) of the 9 thoracoscopic repairs without patch and 1 (12%) of the 8 with a patch developed a recurrence. All these recurrences were repaired thoracoscopically. The 3 recurrences from the thoracoscopic primary repair were repaired using a patch. In the open group, 3 patients (13%) developed a recurrence, of whom 2 were repaired thoracoscopically. Mean operative time was significantly longer in the thoracoscopic patch repair group (158 minutes), when compared to the open repair group (125 minutes). CONCLUSION: As in open repair, it seems wise to use large patches liberally, not only to reconstruct the dome of the diaphragm but also to avoid undue tension on the repair and prevent recurrences. The thoracoscopic approach is also considered feasible in case of a recurrence from either a thoracoscopic or open repair.