Lee M. Morris

High-risk fetal congenital pulmonary airway malformations have a variable response to steroids

BACKGROUND/PURPOSE Anecdotal reports suggest that maternal steroids may arrest the growth of congenital pulmonary airway malformations (CPAMs), preventing or reversing hydrops. We reviewed our experience with CPAMs to determine the fetal response to steroid therapy. METHODS This study is a retrospective review of all fetal CPAMs from 2004 to 2008. Fetuses with high-risk CPAMs that received at least one course of steroids were identified. Fetal magnetic resonance imaging and ultrasound data were used to classify the CPAMs, identify hydrops fetalis and follow the fetuses poststeroid dosing. RESULTS Forty-four fetuses with CPAM were identified. Fifteen patients were found to have received at least one course of steroids. Thirteen were hydropic and 2 were nonhydropic. Seven of the 13 hydropic fetuses (54%) showed an initial response to steroid administration, whereas the 2 nonhydropic high-risk fetuses progressed to birth without developing hydrops. Seven of the 15 patients, however, resulted in fetal demise or early postnatal death, giving a survival rate of 53%. CONCLUSIONS High-risk CPAMs have a variable response to steroids. This variable response demonstrates the need for a placebo-controlled randomized study to more accurately determine the effect of steroids on hydrops and CPAM growth rates. Repeated steroid courses may not be helpful, and progression in CPAM volume to head circumference ratio (CVR) or hydrops should prompt open fetal surgery to prevent irreversible fetal insult.

Congenital High Airway Obstruction Syndrome due to Complete Tracheal Agenesis: An Accident of Nature with Clues for Tracheal Development and Lessons in Management

Congenital high airway obstruction syndrome (CHAOS) is a life-threatening condition characterized by complete blockage of the fetal airways associated with hydrops. We present a case of CHAOS due to the rare cause of complete tracheal agenesis. The ex utero intrapartum therapy (EXIT) strategy was employed to allow for neck and mediastinal exploration. Thymectomy allowed dissection to the level of the carina demonstrating the confluence of dilated mainstem bronchi but no trachea and no connection to the esophagus. A 2.5 endotracheal tube was inserted into the right mainstem bronchus and secured to the left clavicle. At 3 months of age, the infant succumbed to sepsis from Enterobacter mediastinitis due to friction between the tracheostomy tube and the nasogastric tube resulting in erosion of the esophagus. Complete tracheal agenesis, as seen in this case, is consistent with the failure of normal tracheal elongation as suggested by newer theories of foregut development. This case illustrates the most severe form of tracheal atresia causing CHAOS ever salvaged by the EXIT procedure at birth. The subsequent postnatal course highlights the need for early tracheal replacement in this particularly challenging form of CHAOS.

Severe micrognathia: indications for EXIT-to-Airway.

The ex utero intrapartum treatment (EXIT) procedure has become an important management option in cases of fetal airway obstruction. Select cases of severe micrognathia may be candidates for EXIT-to-Airway due to high-risk of airway obstruction at birth. Here we present three successful EXIT-to-Airway procedures for the management of congenital micrognathia in its most severe manifestations. Case 1: A 23-year-old G3P1011 with a pregnancy complicated by severe micorgnathia, jaw index <5th percentile, as well as polyhydramnios. At 36 weeks EXIT-to-Airway was performed utilizing a bronchoscopically positioned laryngeal mask airway (LMA) during 23 min of uteroplacental support followed by tracheostomy. Case 2: A 26-year-old G4P0120 with a pregnancy complicated by severe micrognathia, jaw index <5th percentile, and an obstructed oropharynx associated with polyhydramnios. At 37 weeks EXIT-to-Airway was performed with placement of tracheostomy. Case 3: A 36-year-old G6P3023 with fetal magnetic resonance imaging (MRI) revealing esophageal atresia, polyhydramnios, and severe micrognathia with a jaw index <5th percentile. At 35 weeks the patient underwent EXIT-to-Airway with formal tracheostomy during 35 min of uteroplacental bypass. In the most severe cases of fetal micrognathia, EXIT-to-Airway provides time to evaluate and secure the fetal airway prior to delivery. We propose indications for EXIT-to-Airway in micrognathia to include a jaw index <5%, with indirect evidence of aerodigestive tract obstruction such as polyhydramnios, glossoptosis or an absent stomach bubble.

Characterization of endothelial progenitor cells mobilization following cutaneous wounding

Bone marrow (BM)‐derived endothelial progenitor cells (EPCs) are known to play an important role in neovascularization and wound healing. We investigated the temporal effects of cutaneous wounding on EPC surface markers within the peripheral blood and BM, and to better understand the role of the stromal cell‐derived factor‐1 alpha (SDF‐1α/CXCR4) axis on EPC mobilization after wounding. FVB/NJ mice were administered bilateral 8 mm circular full‐thickness skin wounds. Peripheral blood and BM were isolated at daily intervals postwounding through day 7 and analyzed for EPC mobilization characteristics and levels of SDF‐1α. Cutaneous wounding was found to cause a transient increase in EPC mobilization that peaked on day 3. In contrast, SDF‐1α protein within blood plasma was observed to significantly decrease on days 3, 4, and 7 following cutaneous wounding. BM levels of SDF‐1α protein decreased to a nadir on day 3, the same day as peak mobilization was observed to occur. The decrease in BM SDF‐1α protein levels was also associated with a decrease in SDF‐1α mRNA suggesting transcriptional down‐regulation as a contributing factor. This study for the first time characterizes EPC mobilization following cutaneous wounding in mice and supports a major role for the SDF‐1α/CXCR4 axis in regulating mobilization within the BM, without evidence for systemic increases in SDF‐1α.

Submucosal gland development in the human fetal trachea xenograft model: implications for fetal gene therapy☆

BACKGROUND/PURPOSE Our previous work in a human-fetal trachea xenograft model suggests potential benefits of treating cystic fibrosis in utero. The target for postnatal gene therapy in cystic fibrosis is tracheal submucosal glands (SMGs). The aim of this study was to determine if SMG development in our model recapitulates normal trachea development and its validity for studying fetal gene transfer. METHODS Fetal tracheas were divided into developmental phases: early, mid, and late. Fetal tracheas were xenografted onto immunocompromised mice and analyzed for SMG developmental staging and mucopolysaccharide production. RESULTS There were no significant differences in gland number, size, or density from early through late phase between groups. Xenografted tracheas demonstrated a similar progression through the stages of SMG development as controls after an initial phase shift. Control and xenografted tracheas demonstrated characteristic patterns of acidic mucin production at the base of the SMGs. CONCLUSIONS Fetal trachea xenograft SMG recapitulates normal development and is a valid model for studying human fetal gene transfer. The accessibility of SMG stem cells in early tracheal development may afford a unique window of opportunity for gene transfer. This model has the benefit of providing access to human fetal tracheas in vivo and permits the study of novel fetal gene therapy strategies.

Tuberculous peritonitis: a surgical dilemma.

This is a case report of tuberculous peritonitis (TB), an entity which is difficult to diagnose. When TB is found in extrapulmonary organs it is usually associated with an immunocompromised state, such as that caused by the human immunodeficiency virus (HIV). Medical therapy continues to be the treatment of choice and, if the correct diagnosis is made early, surgery is rarely required.

Compensatory lung growth in NOS3 knockout mice suggests synthase isoform redundancy.

Nitric oxide synthase 3 (NOS3) produces nitric oxide (NO) in endothelial cells, which stimulates cyclic guanosine monophosphate (cGMP) production and thereby mediates pulmonary vasodilation. Inhibition of cGMP enzymatic cleavage by sildenafil might be involved in lung growth stimulating processes in pulmonary hypoplasia. The aim of this study was to discover insights into the transcriptional regulation of NOS3 in a mouse model of compensatory lung growth (CLG). CLG was studied in wild type animals (WT) and NOS3 knockout mice (NOS3-/-) by dry weight, DNA, and protein quantification as well as relative quantification of NOS mRNA. All assessments were done on adult female mice, 10 days after left pneumonectomy (PNX) or sham thoracotomy. Weight ratios of right NOS3-/- lungs were no different than controls. There was a compensatory increase in DNA and a noncompensating increase in protein ratios in NOS3-/- mice compared with controls. Pharmacological knockdown with the pan-NOS inhibitor l-NAME (nitro-arginine methyl ester) reduced CLG by only 8% compared with the d-NAME treated control mice. Relative quantification of lung mRNA revealed no up-regulation of NOS3 expression in WT lungs after PNX, but NOS3-/- lungs showed a 2.6-fold higher inducible NOS2 expression compared with shams. These data suggest that NOS3 loss of function alone does not impair CLG in mice, possibly because of redundancy mechanisms involving NOS2.