Treatment Of Congenital Diaphragmatic Hernia Research Articles

Congenital diaphragmatic hernia: outcome review of 2,173 surgical repairs in US infants

Congenital diaphragmatic hernia (CDH) remains one of the most challenging conditions to treat within the pediatric surgical and medical communities. In spite of modern treatment modalities, including extracorporeal membrane oxygenation (ECMO) and improved ventilatory support, mortality remains high. The present study analyzes a US database containing information from nearly 93 million discharges in the US. Infants with congenital diaphragmatic hernia who underwent surgical repair were identified by ICD-9 procedure code and inclusion criteria including an age at admission of less than 1 year. Variables of gender, race, age, geographic region, co-existing diagnoses and procedures, hospital type, hospital charges adjusted to 2006 dollars, length of stay, and inpatient mortality were collected. A total of 89% of patients were either treated initially or rapidly transferred to urban teaching hospitals for definitive treatment of CDH. The inpatient mortality rate was 10.4% with a median length of stay of 20 days (interquartile range of 9-40 days). The median inflation-adjusted total hospital charge was $116,210. Respiratory distress was the most common co-existing condition (68.8%) followed by esophageal reflux (27.8%). The most common concomitant procedures performed were ECMO (17.8%) and fundoplication (17.6%). This study, which represents the largest characterization of US infants who have undergone CDH repair using data from a nationally representative non-voluntary database, demonstrates that surgical repair is associated with significant mortality and morbidity.

Patent ductus arteriosus flow patterns in the treatment of congenital diaphragmatic hernia

Congenital diaphragmatic hernia (CDH) mortality still remains high, due to lung hypoplasia and persistent pulmonary hypertension of the neonate (PPHN). Effective management of PPHN and time of operation are quite important to the improvement of CDH treatment. In order to determine the optimal time for operation, we monitored PPHN with cardiac ultrasound. PPHN was assessed with three parameters: patent ductus arteriosus flow patterns (PDAFP), %left ventricular diameter at diastole, and left ventricular fraction of shortening (LVFS). Four patients with an antenatal diagnosis were treated under this protocol. Diaphragm repair was performed when PDAFP became left to right shunt dominant and the pre- and postoperative course was analyzed with regular chart reviews. The alveolar-arterial oxygen difference levels of four patients were 590, 335, 613 and 530 mmHg, and operations were carried out when the patients were 2, 2, 3 and 2 days old, respectively. In three of the four patients (all except case 3) the PDAFP changed from right to left shunt dominant or bidirectional (BD), to left to right shunt dominant within 48 h. The %left ventricular diameter at diastole was relatively stable around the time of operation. The LVFS of all patients decreased after the operation. Only the LVFS of case 3 decreased temporarily to less than 30% (which indicates poor left ventricular function) but recovered. No patients needed extracorporeal membrane oxygenation support. All patients survived the procedure and were extubated. Case 3, who took 10 days to become left to right shunt dominant after the operation, needed home oxygenation therapy for 10 months. PDAFP was a reliable marker of PPHN on a high-frequency oscillatory ventilator to determine the optimal time for the operation for CDH. The optimal time for operation is supposed to be the time when PDAFP become left to right shunt dominant.

Congenital diaphragmatic hernia: current status and review of the literature

Treatment of congenital diaphragmatic hernia (CDH) challenges obstetricians, pediatric surgeons, and neonatologists. Persistent pulmonary hypertension (PPHT) associated with lung hypoplasia in CDH leads to a high mortality rate at birth. PPHT is principally due to an increased muscularization of the arterioles. Management of CDH has been greatly improved by the introduction of prenatal surgical intervention with tracheal obstruction (TO) and by more appropriate postnatal care. TO appears to accelerate fetal lung growth and to increase the number of capillary vessels and alveoli. Improvement of postnatal care over the last years is mainly due to the avoidance of lung injury by applying low peak inflation pressure during ventilation. The benefits of other drugs or technical improvements such as the use of inhaled nitric oxide or extracorporeal membrane oxygenation (ECMO) are still being debated and no single strategy is accepted worldwide. Despite intensive clinical and experimental research, the treatment of newborn with CDH remains difficult.

Thoracoscopic Repair of Neonatal Diaphragmatic Hernia

The use of minimally invasive surgery (MIS) in the neonatal population is increasing. Thoracoscopic intervention for congenital diaphragmatic hernia (CDH) is no exception. In this report, we describe our initial experience with thoracoscopic repair of left-sided diaphragmatic defects in neonates. We performed retrospective chart reviews on all neonates who underwent thoracoscopic repair of CDH between November 2004 and January 2008. Neonates that underwent thoracoscopic repair were physiologically stable with resolved pulmonary hypertension and minimal to moderate ventilatory support. They had no associated cardiac anomalies. We identified 15 neonates with CDH who underwent thoracoscopic repair during the study period. Ten neonates underwent primary repair of the diaphragmatic defect. Five neonates with large defects required closure with a synthetic patch, which was placed thoracoscopically. The average operating room time was 134 minutes. There were no instances of intraoperative respiratory or cardiac instability. Three patients had a recurrence. One recurrence was seen after thoracoscopic patch repair. Two recurrences occurred following primary repair of left diaphragmatic hernias. There were no deaths. Follow-up has been 4-40 months. Neonatal MIS for CDH should be limited to stable patients. The ideal candidate is the newborn without associated anomalies, not requiring extracorporeal membrane oxygenation, on minimal ventilatory support, and without evidence of pulmonary hypertension. It is technically possible to perform thoracoscopic repair with a patch.

Successful treatment of congenital diaphragmatic hernia (CDH) associated with pancreatic hypoplasia — Case report

Successful treatment of congenital diaphragmatic hernia (CDH) associated with pancreatic hypoplasia — Case report

Platelet-derived growth factor inhibition—a new treatment of pulmonary hypertension in congenital diaphragmatic hernia?

Increased pulmonary vascular resistance causing pulmonary artery hypertension is a major problem in the treatment of congenital diaphragmatic hernia with a strong association to mortality. We here report a patient with intractable pulmonary hypertension at 4 weeks of age unresponsive to conventional treatment. After administration of the platelet-derived growth factor (PDGF) receptor antagonist imatinib, pulmonary artery pressure gradually decreased to acceptable levels and the patient's clinical condition gradually improved.

Main bronchus occlusion for treatment of congenital diaphragmatic hernia in fetal lambs

Purpose The present study investigates a new surgical approach in the treatment of left diaphragmatic hernia in fetal sheep. We postulated that unlike tracheal occlusion where both lungs are occluded, selective left main bronchus occlusion (LMBO) would accelerate growth of only the left lung, reduce left visceral herniation, and recover space in the both thoraces necessary for lung development. Methods Left-sided congenital diaphragmatic hernia (CDH) was surgically created in 8 fetal lambs at approximately 65 days of gestation; in 4 of these animals, LMBO was performed at approximately 118 days. Four sham-operated animals served as controls. Lambs were delivered by hysterotomy at 137 days. We measured lung-to-body weight ratios, alveolar surface area, septal wall thickness, and AE2 cell density in the left and right lungs. Results Left main bronchus occlusion increased ( P < .05) left lung growth causing severe right mediastinal shift but failed to reduce herniated abdominal viscera in 3 of 4 lambs. Wet lung-to-body weight ratio in LMBO group was similar to that of the control group; however, this was achieved by overgrowth of left lung, whereas the right wet lung-to-body weight ratio remained low. In the LMBO group, right lung AE2 cell density was higher than that of control group and not different to that of the CDH group. Conclusions Left main bronchus occlusion failed to restore normal pulmonary development in CDH.

Effect of antenatal tetrandrine administration on endothelin-1 and epidermal growth factor levels in the lungs of rats with experimental diaphragmatic hernia

Purpose The aim of this study was to evaluate the effect of the traditional Chinese medicine tetrandrine (Tet) and to determine its possible mechanism on expression of endothelin-1 (ET-1) and epidermal growth factor (EGF) in the lung of a rat model of nitrofen-induced congenital diaphragmatic hernia (CDH). Methods A single oral dose (115 mg/kg) of nitrofen on day 9.5 of pregnancy was maternally administered to induce CDH. Pregnant rats were divided into 4 groups on day 18.5: control (n = 5), CDH (n = 5), CDH+dexamethasone (Dex) (n = 5), and CDH+Tet (n = 5). All fetuses were delivered by cesarean delivery on day 21.5. Accordingly, there were 4 groups of fetuses: control (n = 38), CDH (n = 25), CDH+Dex (n = 21), and CDH+Tet (n = 22). Lung tissue weight (LW) and body weight (BW) of each fetus were recorded, lung histologic evaluations and ET-1 and EGF immunohistochemistry staining were performed, and image analysis was performed after lung processing. Results Five female rats in the control group produced 38 fetuses without CDH. CDH was observed in 68 of the 128 rat fetuses (53.1%) among the other 3 groups. The LW/BW ratio of the CDH group was significantly lower than those of the Dex and EGF groups ( P < .05). The lungs of fetuses with CDH showed marked abnormal structure such as pulmonary hypoplasia and vascular remodeling, in contrast to improved pulmonary structure in lungs of fetuses in the CDH+Dex and CDH+Tet groups. Statistical differences in morphologic parameters (radial alveolar counts, percentage of alveoli, percentage of medial wall thickness, and vascular volume) were found ( P < .05). The immunoreactivity of EGF and ET-1 in the CDH group was markedly stronger than that in the control, CDH+Dex, and CDH+Tet groups ( P < .01). In addition, EGF and ET-1 expression in the CDH+Dex and CDH+Tet groups was stronger than that in the control group ( P < .05). There was no difference in lung EGF and ET-1 immunoreactivity between CDH+Dex and CDH+Tet groups ( P > .05). Conclusion Antenatal treatment with Tet may improve lung growth and vascular remodeling, and its mechanism seems to be involved in decreasing EGF and ET-1 expression. Tet administered maternally may be a hopeful new therapeutic option in the treatment of CDH and may be effective in helping to avoid the side effects of Dex.

Retrospective study of 111 cases of congenital diaphragmatic hernia treated with early high-frequency oscillatory ventilation and presurgical stabilization

Background The prognosis of babies with congenital diaphragmatic hernia (CDH) remains unsatisfactory despite recent advances in medical and surgical treatment. Most authors agree that the best way to improve outcomes for this disease is to focus on pulmonary hypoplasia and persistent pulmonary hypertension (PPH), the 2 most unfavorable prognostic factors for patient survival. However, controversy remains regarding the best treatment of CDH. In the past decade, several institutions have developed treatment protocols that include high-frequency oscillatory ventilation (HFOV), preoperative stabilization, and no thoracic drain. This strategy is 1 of several “gentle ventilation” strategies. We describe our 10-year experience in treating a cohort of 111 infants with CDH managed with this “gentle ventilation” strategy. Methods From October 1994 to June 2005, 111 babies with CDH were treated at our institution with HFOV. Babies progressed to inhaled nitric oxide and extracorporeal membrane oxygenation if severe PPH persisted. After a period of preoperative stabilization, surgery was performed via an abdominal approach. In case of large defects or diaphragmatic agenesis, a prosthetic patch was used. No thoracic drain was left in place at the end of surgery. The charts of all babies were reviewed. General characteristics, respiratory management, as well as perioperative and postoperative data were analyzed and correlated with survival. Predicted and actual survival rates in high-, intermediate-, and low-risk groups were analyzed on the basis of the equation described by the Congenital Diaphragmatic Hernia Study Group in 2001. Results The overall survival rate in our group of patients with CDH was 69.4% regardless of side of the defect. Incidence of a prenatal diagnosis before the 25th gestational week, coexistence of severe congenital heart disease (overall incidence, 5.4%), or other major associated anomalies, as well as the presence of a diaphragmatic agenesis were significantly higher in nonsurvivors. Thirty-six had severe PPH, of which 26 (76.5% of nonsurviving patients) died. Survivors and nonsurvivors had significant differences in blood gas analysis and respiratory management data recorded before and after the diaphragmatic correction. Ninety-nine (89%) patients underwent correction of the diaphragmatic defect. A patch was used in 44 (44%) patients and 15 of them died (survivors, 37.7%; nonsurvivors, 68.2%; P = .0111). Six (43%) of 14 patients with a preoperative pneumothorax (survivors, 10.3%; nonsurvivors, 27.3%; P > .05) and 7 (58%) of 12 patients with a postoperative pneumothorax needing a thoracic drain (survivors, 6.5%; nonsurvivors, 31.8%; P = .0013) died. In all cases, pneumothorax was ipsilateral. Two patients required oxygen therapy at discharge. The predicted survival rate was 69%; there was no difference between predicted and actual overall survival as well as between predicted and actual survival in low-risk (predicted survival rate, >66%), intermediate-risk (predicted survival rate, 34%-66%), and high-risk (predicted survival rate, <33%) groups. Conclusions The CDH treatment strategy that includes HFOV, preoperative stabilization and no thoracic drain ensures survival with minimal pulmonary morbidity (low rate of pulmonary infections and low rate of patients requiring oxygen at home) in most affected babies. Persistent pulmonary hypertension has been the most challenging factor that ultimately determined the final outcome, and availability of new vasoactive drugs is mandatory to ameliorate the prognosis especially in high-risk patients. Meanwhile, survival comparisons of low-, intermediate-, and high-risk groups between institutions using different protocols will allow the identification of the best strategy for CDH management.

Pleural and pericardial effusion: a potential ultrasonographic marker for the prenatal differential diagnosis between congenital diaphragmatic eventration and congenital diaphragmatic hernia

To determine whether or not the presence of pleural and/or pericardial effusion can be used prenatally as an ultrasonographic marker for the differential diagnosis between diaphragmatic eventration and diaphragmatic hernia. We present two case reports of non-isolated diaphragmatic eventration associated with pleural and/or pericardial effusion. Additionally, we reviewed the literature for all cases of congenital diaphragmatic hernia (CDH) and diaphragmatic eventration that met the following criteria: (1) prenatal diagnosis of a diaphragmatic defect and (2) definitive diagnosis by autopsy or surgery. The frequencies of pleural effusion, pericardial effusion and hydrops were compared between the two conditions using Fisher's exact test. A subanalysis was conducted of cases with isolated diaphragmatic defects (i.e. diaphragmatic defects not associated with hydrops and other major structural or chromosomal anomalies). A higher proportion of fetuses with diaphragmatic eventration had associated pleural and pericardial effusions compared with fetuses with diaphragmatic hernia (58% (7/12) vs. 3.7% (14/382), respectively, P < 0.001). This observation remained true when only cases of diaphragmatic defects not associated with hydrops and other major structural or chromosomal anomalies were compared (29% (2/7) with eventration vs. 2.2% (4/178) with CDH, P < 0.02). The presence of pleural and/or pericardial effusion in patients with diaphragmatic defects should raise the possibility of a congenital diaphragmatic eventration. This information is clinically important for management and counseling because the prognosis and treatment for CDH and congenital diaphragmatic eventration are different. Published by John Wiley & Sons, Ltd.

Effect of tetrandrine on lung development: experiment of nitrofen-induced congenital diaphragmatic hernia fetal rat model

To assess the efficacy of prenatal administration of tetrandrine (TET) on pulmonary hypoplasia in the nitrofen-induced congenital diaphragmatic hernia (CDH) fetal rat model. Six timed-pregnant female Sprague-Dawley rats were randomly divided into 3 equal groups: CDH group (receiving gavage of nitrofen 125 mg dissolved in seed fat on day 9.5), and TET group (receiving gavage of nitrofen 125 mg on day 9.5 and then gavage of TET 30 mg/kg on days 11.5 - 14.5), and control group (given the same dose of peanut oil on day 9.5 and the same dose of normal saline on days 11.5 - 14.5). The fetuses were delivered by cesarean section on day 21 to undergo light microscopy and electron microscopy. The numbers of type II pneumocytes were recorded and compared. CDH were detected in 32 of the 41 fetuses from the CDH and TET groups with a teratogenic rate of 78%, however, without a significant difference between the CDH and TET groups (P = 0.645). Microscopy showed significant lung hypoplasia in both histologic structure and cellular structure in the CDH group; however the lung development of the TET group was improved in comparison to the CDH group. There was no significant difference in numbers of type II pneumocytes among the 3 groups (P = 0.779). Prenatal administration of TET can improve the lung development of CDH rats in both histological structure and cellular structure. This may provide a new idea for the clinical treatment of CDH.

Risk factors for sensorineural hearing loss in survivors with severe congenital diaphragmatic hernia

Recent improvements in perinatal management have improved the prognosis in patients with severe congenital diaphragmatic hernia (CDH). However, in surviving patients with severe CDH, hearing loss has sometimes been reported to occur during the follow-up period. Although some of the risk factors for developing sensorineural hearing loss (SNHL) have been reported in CDH, no definitive risk factors have yet been reported. We, therefore, investigated the risk factors regarding postnatal management in patients with severe CDH. In 16 surviving patients with severe CDH, which had all been detected antenatally, and whose lung-to-thoracic ratio was less than 0.2, four patients demonstrated late onset SNHL, which occurred between 1.5 and 5 years of age. The risk factors for SNHL regarding the postnatal treatment for CDH were analyzed between the four patients with SNHL and the remaining 12 patients without SNHL, regarding such factors as the use of ototoxic drugs, neuromuscular blocking agents, high-frequency oscillation (HFO), and inhaled nitric oxide, the duration of hypocapnia, hypoxia, severe acidosis, severe alkalosis, and mechanical ventilation. In addition, the types of neuromuscular blocking agents were also analyzed, including the administration of pancuronium bromide (PB) and vecuronium bromide (VB). The patients with SNHL were found to have a significantly higher risk than the patients without SNHL regarding the duration of loop diuretics usage and the duration of usage of both mechanical ventilation and HFO. Furthermore, all four patients with SNHL used PB. In contrast, none of the five patients using VB developed SNHL The duration and cumulative dose of PB used in the patients with severe CDH showed a significant correlation to the occurrence of SNHL. Although this study was retrospective, based on our data, the prolonged use of PB, in addition to the duration of treatment by loop diuretics, mechanical ventilation, and HFO usage, might, thus, be suggested to be a possible risk factor for late onset SNHL in patients with severe CDH.

Telemetric monitoring of tracheal pressure after tracheal occlusion for treatment of severe congenital diaphragmatic hernia

Prenatal tracheal occlusion using endoscopic techniques obstructs the normal egress of lung fluid during pulmonary development and stimulates lung growth in cases of congenital diaphragmatic hernia (CDH). Although FETO might be an effective strategy for treatment of CDH, the mechanism especially due to the supposed increasing transpulmonary pressure is unknown. The purpose of this study was to monitor the pressure below the attached balloon in the fetal lamb telemetrically. Four time-dated pregnant Merino ewes underwent fetal and maternal surgery. A special prepared silicone catheter was placed below the epiglottis by laryngoscopy on day 110 or 140 of gestation. The tracheal pressure below the fixed catheter could be monitored telemetrically using the Data Sciences TA11-PA-C40 pressure device. Hundred and twenty measurement points were recorded over a period of 2 min. A maximum of lung pressure rate was found immediately after implantation (23.7 +/- 4.6 mm Hg). During the first hour, the pressure decreased to an average value of 16.9 mmHg. About 70 h after the block, this value decreased to a minimum level of 8.3 +/- 0.4 mmHg. Decreasing pressure variation might indicate that lung growth has stopped and that the ideal point of time to remove the balloon is achieved. Increasing pressure has to be related to the morphometric analysis of the lung's structural development and maturation, comparing the efficacy of FETO in preventing or reversing pulmonary hypoplasia. Further investigation of continuous telemetric monitoring of tracheal pressure in the fetal lamb is required.

Fetal surgery for congenital diaphragmatic hernia

Congenital diaphragmatic hernia (CDH) continues to account for significant mortality in neonates. Advances in postnatal therapies have reduced mortality rates in the less severely affected infants, though surviving infants continue to display significant comorbid conditions. The history of fetal treatment for CDH is a microcosm for the development of fetal therapy in general. This paper traces this history from early clinical observations and imaging advances to experimental animal studies and finally to safe human application and development of clinical trails. Encouraging recent results and improved outcomes lend credence to the idea than prenatal interventions may give clinicians and families more hope.

The pathology, diagnosis, and treatment of congenital diaphragmatic hernia in infants

The pathology, diagnosis, and treatment of congenital diaphragmatic hernia in infants

Foetal surgery and cleft lip and palate: current status and new perspectives

Now-a-days, high-resolution ultrasound allows an accurate and relatively early diagnosis of congenital malformations. In a limited number of such conditions foetal surgery may be lifesaving. However, premature labour has been the major drawback for open foetal surgery. Recently, improvement of video-endoscopic technology has boosted the development of operative techniques for feto-endoscopic surgery, which has been demonstrated to be less invasive than the open approach. Main clinical application of fetoscopic procedures today is the treatment of feto-foetal transfusion syndrome. Although still in development, feto-endoscopic surgery seems to offer new hope for surgical foetal therapy not only in cases of life threatening conditions. Experimental intrauterine correction of cleft lip and palate (CLP) has been lately performed using the feto-endoscopic approach. This procedure offers two major advantages: first, scarless foetal wound healing and bone healing without callus formation, which would also allow a better/normal maxillary growth, and second, significant decrease of foetal and maternal morbidity. Herein, we report the current status of experimental and clinical foetal surgery and propose possible directions for continuing research to make intrauterine procedures safer. Furthermore, we discuss current knowledge and new perspectives of experimental foetal cleft lip and palate repair, which in the future may lead to such excellent results in the operative treatment of clefts, that less or no secondary corrections and therapies, such as orthodontic, dental, logopedic, etc. would be needed. Only if these conditions can be fulfilled, will we be able to improve substantially our therapy for the human foetus with a cleft lip and palate. In spite of all efforts, however, it must be considered that it may not ever be possible to find the optimal treatment method for this or other craniofacial malformations.

Congenital diaphragmatic hernia: A retinoid‐signaling pathway disruption during lung development?

Congenital diaphragmatic hernia (CDH) usually occurs sporadically. The prognosis remains poor, with a 50% perinatal mortality rate. Most deaths result from hypoxemia due to lung hypoplasia and abnormal development of pulmonary vasculature that results in persistent pulmonary hypertension. Our current understanding of the pathogenesis of CDH is based on an assumption linking herniation of abdominal viscera into the thorax with compression of the developing lung. Pulmonary hypoplasia, however, can also result from reduced distension of the developing lung secondary to impaired fetal breathing movements. Moreover, a nitrofen-induced CDH model shows that lung hypoplasia precedes the diaphragmatic defect, leading to a "dual-hit hypothesis." Recent data reveal the role of a retinoid-signaling pathway disruption in the pathogenesis of CDH. We describe the clinical and epidemiological aspects of human CDH, the metabolic and molecular aspects of the retinoid-signaling pathway, and the implications of retinoids in the development of the diaphragm and the lung. Finally, we highlight the existing links between CDH and disruption of the retinoid-signaling pathway, which may suggest an eventual use of retinoids in the treatment of CDH.

Congenital diaphragmatic hernia: a survey of practice in Scandinavia.

There is no consensus on the treatment of congenital diaphragmatic hernia (CDH), and practice seems to vary between centres. The main purpose of the present study was to survey current practice in Scandinavia. Thirteen paediatric surgical centres serving a population of about 22 million were invited, and all participated. One questionnaire was completed at each centre. The questionnaire evaluated management following prenatal diagnosis, intensive care strategies, operative treatment, and long-term follow-up. Survival data (1995-1998) were available from 12 of 13 centres. Following prenatal diagnosis of CDH, vaginal delivery and maternal steroids were used at eight and six centres, respectively. All centres used high-frequency oscillation ventilation (HFOV), nitric oxide (NO), and surfactant comparatively often. Five centres had extracorporeal membrane oxygenation (ECMO) facilities, and four centres transferred ECMO candidates. The majority of centres (7/9) always tried HFOV before ECMO was instituted. Surgery was performed when the neonate was clinically stable (11/13) and when no signs of pulmonary hypertension were detected by echo-Doppler (6/13). The repair was performed by laparotomy at all centres and most commonly with nonabsorbable sutures (8/13). Thoracic drain was used routinely at seven centres. Long-term follow-up at a paediatric surgical centre was uncommon (3/13). Only three centres treated more than five CDH patients per year. Comparing survival in centres treating more than five with those treating five or fewer CDH patients per year, there was a tendency towards better survival in the higher-volume centres (72.4%) than in the centres with lower volume (58.7%), p =0.065.

504. Gene Transfection into Fetal Sheep Airway Epithelium Using Cationic BGTC/DOPE Liposomes

Over the last years, we have developed a particular class of nonviral vectors, cationic cholesterol derivatives characterized by polar headgroups with guanidinium functions. Indeed, guanidinium groups have highly favorable features for DNA binding. Liposome formulations of bis(guanidinium)-tren-cholesterol (BGTC) with dioleoylphosphatidylethanolamine (DOPE) were found to be efficient for gene transfection into primary human airway epithelial cells as well as into the mouse airway epithelium in vivo by intratracheal administration (Proc. Natl. Acad. Sci. USA 1997, 94, 1651-1656). We have also shown that colloidal stabilization (via lipophilic polyethyleneglycol derivatives) of concentrated solutions of BGTC/DOPE lipoplexes allowed enhanced transfection of the mouse airways by intranasal instillation (J. Gene Med. 2001, 3, 478-487). Thus, as prenatal gene therapy may be necessary for the treatment of a variety of congenital lung diseases, we recently undertook to explore the feasibility of BGTC-mediated gene transfection into the respiratory tract of fetal sheep in utero. Practically, pCIK-CAT plasmids expressing the E. coli chloramphenicol acetyltransferase (CAT) reporter gene (kindly provided by D. Gill, Oxford, UK) were complexed with BGTC/DOPE liposomes and the resulting lipoplexes were administered to sheep fetuses at 70 days of gestation via surgical replacement of the fetal airway fluid by the transfection mixture followed by tracheal ligature. The fetal tracheas and lungs were harvested at 72 hours and examined for CAT expression and evidence of toxicity. Using an ELISA assay, we detected significant CAT levels in lung and trachea homogenates, no CAT expression being observed in control fetuses receiving naked pCIK-CAT plasmid. Immunohistochemistry analysis showed that airway epithelial cells (at both the tracheal and bronchial levels) as well as some mesenchymal cells were transfected. Pulmonary histopathology of varied severity was however observed and manifested as focal epithelial and mesenchymal lesions. These results demonstrated that BGTC/DOPE liposomes can mediate gene transfection into the fetal sheep airway epithelium in utero and they also invited the development of optimized BGTC-based formulations with a view to future experiments with therapeutic genes. Thus, we are at present investigating the utility of BGTC-based lipoplexes for transferring genes encoding pulmonary growth factors in the fetal lamb model of congenital diaphragmatic hernia (CDH). In these ongoing experiments, a first surgical step allows the creation of the diaphragmatic hernia, whereas the second step consists of the substitution of the fetal airway fluid by the lipoplex medium followed by tracheal occlusion via a balloon. Nonviral gene delivery approaches may be particularly attractive here as long-term transgene expression is probably not required for the treatment of CDH before birth.

Which Treatment for Congenital Diaphragmatic Hernia Diagnosed in Utero

Congenital diaphragmatic hernia in fetuses can be diagnosed by ultrasound early in pregnancy. Rates of postnatal mortality are high for fetuses with