Intrauterine tracheal obstruction, a new treatment for congenital diaphragmatic hernia, decreases amniotic fluid sodium and chloride concentrations in the fetal lamb

Single-cell guided prenatal derivation of primary fetal epithelial organoids from human amniotic and tracheal fluids

Isolation of tissue-specific fetal stem cells and derivation of primary organoids is limited to samples obtained from termination of pregnancies, hampering prenatal investigation of fetal development and congenital diseases. Therefore, new patient-specific in vitro models are needed. To this aim, isolation and expansion of fetal stem cells during pregnancy, without the need for tissue samples or reprogramming, would be advantageous. Amniotic fluid (AF) is a source of cells from multiple developing organs. Using single-cell analysis, we characterized the cellular identities present in human AF. We identified and isolated viable epithelial stem/progenitor cells of fetal gastrointestinal, renal and pulmonary origin. Upon culture, these cells formed clonal epithelial organoids, manifesting small intestine, kidney tubule and lung identity. AF organoids exhibit transcriptomic, protein expression and functional features of their tissue of origin. With relevance for prenatal disease modeling, we derived lung organoids from AF and tracheal fluid cells of congenital diaphragmatic hernia fetuses, recapitulating some features of the disease. AF organoids are derived in a timeline compatible with prenatal intervention, potentially allowing investigation of therapeutic tools and regenerative medicine strategies personalized to the fetus at clinically relevant developmental stages.

Fetal endoscopic tracheal occlusion for congenital diaphragmatic hernia: a narrative review of the history, current practice, and future directions

Fetal intervention for fetuses with congenital diaphragmatic hernia (CDH) has been investigated for over 30 years and is summarized in this manuscript. The review begins with a discussion of the history of fetal intervention for this severe congenital anomaly beginning with open fetal surgery with repair of the anatomical defect, shifting towards tracheal occlusion via open surgery techniques, and finally fetoscopic endoluminal balloon tracheal occlusion using a percutaneous approach. The current technique of fetal endoscopic tracheal occlusion (FETO) is described in detail with steps of the procedure and complementary figures. The main outcomes of single-institutional studies and multiple systematic reviews are examined and discussed. Despite these studies, the fetal community agrees that FETO remains investigational at this time as there is insufficient evidence to recommend it as the standard of care for CDH. A randomized controlled trial, The Tracheal Occlusion to Accelerate Lung Growth (TOTAL) trial, has been designed to attempt to answer this question in an elaborate, international, multi-institutional study and is described in the text. Finally, future directions of fetal intervention for antenatally diagnosed CDH are discussed, including options for non-isolated CDH, the Smart-TO balloon for nonoperative reversal of occlusion, and transplacental sildenafil for treatment of pulmonary hypertension prior to birth.

TACRD and VACTERL associations in a fetus: case report and review of the literature

Tracheal agenesis is a rare and potentially lethal congenital anomaly. The incidence is less than 1/50,000, with a male:female ratio of 2:1. We report the case of a male fetus with complete agenesis of the trachea and a tracheoesophageal fistula arising from the esophagus that connected through the carina, as well as several abnormalities (congenital cardiac abnormalities, duodenal atresia, vertebral defects, anal atresia, renal defects, limb defects, and diaphragmatic hernia). To our knowledge, few cases of infants with VACTERL or TACRD association have been reported to date. Here, we report a new case of a fetus that showed the full range of VACTERL and TACRD associations.

Evaluation of the development of lung hypoplasia in the premature lamb

BACKGROUND

The death rate from human diaphragmatic hernia (CDH) ranges from 50 to 80%, mainly due to the associated lung hypoplasia. To prevent these irreversible pathological and physical defects, the question of intrauterine surgical intervention arises. The histological changes of the lung tissue after inducement of a diaphragmatic hernia were examined. Of special interest was the time elapsing until the development of lung hypoplasia.

METHODS

A model of intrauterine inducement of diaphragmatic hernia was established using five fetal lambs to study consecutive pulmonary hypoplasia. Inducement of a diaphragmatic hernia was undertaken between 105 and 108 days' gestation. Lung tissue was examined histologically on postoperative days 8, 17, 21, 22, and 25 after inducement of the defect.

RESULTS

On postoperative days 8, 17, and 21, no signs of pulmonary hypoplasia were found on histological examination. A pulmonary hypoplasia was found in two fetuses (on the 22nd and 25th postoperative day). The pathological and anatomical examination of a unilateral pulmonary hypoplasia after a short period of time shows that the artificially created diaphragmatic defect is a good model for producing a congenital diaphragmatic hernia.

DISCUSSION

The severity of the pulmonary hypoplasia is related to the duration of lung compression by the herniated organs. The time elapsing until the development of lung hypoplasia is shorter than expected. Tracheal occlusion seems to be an effective strategy for treatment of the defect CDH, but the best technique for achieving occlusion, and particularly the ideal point in time to carry out "Fetendo," are unknown. Further research into this congenital illness is required in order to treat it.

Combination of renal agenesis with respiratory and alimentary tract atresia results in normal lung development

The VACTERL complex comprises renal agenesis and atresias of the alimentary and respiratory tracts. We report on a case with this combination causing severe oligohydramnios but with normal lung development. The likely protective mechanism for pulmonary development was an increase in alveolar pressure and reduced alveolar fluid loss due to the esophageal-tracheal malformation. This suggests the possible treatment of oligohydramnios by tracheal occlusion.

Tracheal side effects of endoscopic balloon tracheal occlusion in the fetal lamb model

OBJECTIVE

To evaluate effects of in-utero endoluminal balloon tracheal occlusion (TO) as suggested for the treatment of Congenital Diaphragmatic Hernia (CDH) on the higher airways of a fetal lamb model.

STUDY DESIGN

Fetuses from time-dated pregnant ewes underwent at 94 days (term=145 days) in-utero tracheal occlusion. In study animals an endoluminal, detachable balloon was placed by tracheoscopy. For that purpose a 1.2mm fibre-optic, semi-rigid endoscope and a medically graded latex balloon were used. In group I (n=9) lambs were delivered after 2 weeks. In group II (n=8) the tracheal occlusion was released after 2 weeks, to allow in-utero recovery until term. In positive control animals (group III; n=5) the trachea was clipped at 98 days and fetuses were harvested near term by cesarean section. A total of 17 contralateral littermates in multiple pregnancies served as negative controls. After macroscopic inspection of the trachea, sections were evaluated by light microscopy. Alterations were scored with an empirical interval score for each of the different anatomical elements in the fetal trachea (epithelium, submucosa, cartilage, pars membranacea).

RESULTS

For the animal experiments in group I, all balloons were found in place and according to the pulmonary response they were obstructive. Tracheas were macroscopically dilated by the plug mainly due to elongation of the pars membranacea. The total histologic score was correlated to the increase in circumference (mean increase: 3.0mm). In nearly all cases, the tracheal epithelium at the level of the plug had lost its typical folding pattern. In 44% of cases, local epithelial defects were observed and in 33% of cases there was squamous metaplasia. A chronic inflammatory response was present in over half of the cases, sometimes with giant cell reaction. In group II (the in-utero recovery group) the total score was significantly lower than in group I, with much less prominent unfolding and absence of epithelial defects. Squamous metaplastia was still present in half of the cases; whereas inflammatory responses were less frequent. In group III the trachea expanded normally after removal of the clip. The epithelium had compacted folds, and cilia were well preserved. In two animals however, intraluminal synechia were observed. Below the level of occlusion animals of groups I and II all showed areas of unfolding, but without metaplasia or epithelial defects.

CONCLUSION

Tracheal obstruction by means of endoluminal plugging has been suggested as an alternative in-utero treatment for congenital diagphragmatic hernia. The balloon causes mild epithelial changes, such as unfolding, limited epithelial defects (<25% of the exposure surface) and local inflammatory changes. These changes disappear nearly completely following in-utero unplugging during the rest of gestation. Unfolding of the epithelium is also seen in the trachea under the plug.

Single-port tracheoscopic surgery in the fetal lamb

BACKGROUND/PURPOSE

Endoscopic fetal surgery could help avoid many of the problems associated with open fetal surgery, but the use of multiple ports may be too traumatic to the membranes. The authors describe a single-port technique of tracheoscopic surgery in the fetus.

METHODS

Time-dated pregnant ewes (95 to 105 days; term, 145 days) underwent midline laparotomy under general halothane anesthesia. A 5-mm-diameter balloon-tipped cannula was introduced in the uterus by Seldinger technique. A 1.2-mm semirigid mini-endoscope, fitted inside a 9F, 20 degrees curved sheath, was introduced under continuous, low-pressure irrigation, inside the fetus' mouth, and advanced into the trachea.

RESULTS

Endotracheal procedures, including temporary (n = 11) and permanent balloon tracheal occlusion (n = 30) and placement of a barbed guide wire for endotracheal occlusion device insertion (n = 12), were performed by introducing a 1-mm diameter instrument alongside the telescope. These were successfully performed in 52 of the 53 fetuses. The rigidity of the telescope allowed controlled access to the pharynx; its curve allowed full tracheobronchial endoscopy with the fetus in utero.

CONCLUSIONS

The present technique marries the control and optical quality of a rigid endoscope with the physiological curve only a flexible instrument could offer until now. The types of procedures performed with this technique illustrate its potential as a research tool; the size (1.2-mm diameter), shape, and optical qualities of the telescope should make clinical applications possible.