1
|
The effects of tracheal occlusion on Wnt signaling in a rabbit model of congenital diaphragmatic hernia. J Pediatr Surg 2019; 54:937-944. [PMID: 30792093 DOI: 10.1016/j.jpedsurg.2019.01.024] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Accepted: 01/27/2019] [Indexed: 12/22/2022]
Abstract
PURPOSE Tracheal occlusion (TO) reverses pulmonary hypoplasia (PH) in congenital diaphragmatic hernia (CDH), but its mechanism of action remains poorly understood. Wnt signaling plays a critical role in lung development, but few studies exist. The purpose of our study was to a) confirm that our CDH rabbit model produced PH which was reversed by TO and b) determine the effects of CDH +/- TO on Wnt signaling. METHODS CDH was created in fetal rabbits at 23 days, TO at 28 days, and lung collection at 31 days. Lung body weight ratio (LBWR) and mean terminal bronchiole density (MTBD) were determined. mRNA and miRNA expression was determined in the left lower lobe using RT-qPCR. RESULTS Fifteen CDH, 15 CDH + TO, 6 sham CDH, and 15 controls survived and were included in the study. LBWR was low in CDH, while CDH + TO was similar to controls (p = 0.003). MTBD was higher in CDH fetuses and restored to control levels in CDH + TO (p < 0.001). Reference genes TOP1, SDHA, and ACTB were consistently expressed within and between treatment groups. miR-33 and MKI67 were increased, and Lgl1 was decreased in CDH + TO. CONCLUSION TO reversed pulmonary hypoplasia and stimulated early Wnt signaling in CDH fetal rabbits. TYPE OF STUDY Basic science, prospective. LEVEL OF EVIDENCE II.
Collapse
|
2
|
Assessment of the nitrofen model of congenital diaphragmatic hernia and of the dysregulated factors involved in pulmonary hypoplasia. Pediatr Surg Int 2019; 35:41-61. [PMID: 30386897 DOI: 10.1007/s00383-018-4375-5] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 10/18/2018] [Indexed: 02/08/2023]
Abstract
PURPOSE To study pulmonary hypoplasia (PH) associated with congenital diaphragmatic hernia (CDH), investigators have been employing a fetal rat model based on nitrofen administration to dams. Herein, we aimed to: (1) investigate the validity of the model, and (2) synthesize the main biological pathways implicated in the development of PH associated with CDH. METHODS Using a defined strategy, we conducted a systematic review of the literature searching for studies reporting the incidence of CDH or factors involved in PH development. We also searched for PH factor interactions, relevance to lung development and to human PH. RESULTS Of 335 full-text articles, 116 reported the incidence of CDH after nitrofen exposure or dysregulated factors in the lungs of nitrofen-exposed rat fetuses. CDH incidence: 54% (27-85%) fetuses developed a diaphragmatic defect, whereas the whole litter had PH in varying degrees. Downregulated signaling pathways included FGF/FGFR, BMP/BMPR, Sonic Hedgehog and retinoid acid signaling pathway, resulting in a delay in early epithelial differentiation, immature distal epithelium and dysfunctional mesenchyme. CONCLUSIONS The nitrofen model effectively reproduces PH as it disrupts pathways that are critical for lung branching morphogenesis and alveolar differentiation. The low CDH rate confirms that PH is an associated phenomenon rather than the result of mechanical compression alone.
Collapse
|
3
|
Combined antenatal therapy with retinoic acid and tracheal occlusion in a rat model of congenital diaphragmatic hernia. Pediatr Surg Int 2016; 32:591-8. [PMID: 26992387 DOI: 10.1007/s00383-016-3886-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 03/09/2016] [Indexed: 10/22/2022]
Abstract
AIM To investigate the effect of combined prenatal treatment with retinoic acid (RA) and tracheal occlusion (TO) on the pulmonary vascular morphology and expression of vascular endothelial growth factors (VEGF) and its receptors in a rat model of congenital diaphragmatic hernia (CDH). MATERIAL AND METHODS Rats were given nitrofen at 9 days of gestation followed by no treatment (CDH), RA (CDH + RA), TO (CDH + TO), or both (CDH + RA + TO) (n = 16). We measured the median wall thickness of the pulmonary arterioles (MWT) and analyzed the expression of VEGF and its receptors (VEGFR1 and VEGFR2). RESULTS Compared to control animals, CDH had increased MWT (44 ± 15 vs. 58 ± 7; p < 0.05) and decreased expression of VEGF, VEGFR1, and VEGFR2 (p < 0.05). Treatment with RA or TO alone, and RA + TO reduced the MWT (46 ± 9, 42 ± 11, 46 ± 8, respectively) and improved the expression of VEGF, VEGFR1, and VEGFR2 compared to CDH (p < 0.05). However, the combination of RA + TO did not confer additional benefit in the reduction of the MWT or in increasing the VEGF and its receptors compared to either treatment alone. CONCLUSION Antenatal treatment with either RA or TO improved the MWT and expression of VEGF and its receptors in a CDH rat model. However, combined treatment with RA + TO was not superior to either treatment alone.
Collapse
|
4
|
Eastwood MP, Russo FM, Toelen J, Deprest J. Medical interventions to reverse pulmonary hypoplasia in the animal model of congenital diaphragmatic hernia: A systematic review. Pediatr Pulmonol 2015; 50:820-38. [PMID: 25994108 DOI: 10.1002/ppul.23206] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/19/2014] [Revised: 02/24/2015] [Accepted: 03/23/2015] [Indexed: 12/25/2022]
Abstract
We aimed to systematically review all published pre-clinical research on prenatal medical treatment of pulmonary hypoplasia in congenital diaphragmatic hernia (CDH). Background The neonatal mortality due to isolated CDH remains high. Whether fetal endoscopic tracheal occlusion (FETO) reduces mortality is still to be demonstrated. Therefore more potent preferentially medical therapy would be welcomed. Methods We searched MEDLINE (Pubmed), Embase and the Web of Science including all studies from the earliest date (1951) to December 2013. Article quality was assessed using the modified CAMRADES checklist. Inclusion criteria were those animal studies addressing prenatal medical interventions and principal variables were confirmation of a diaphragmatic defect, lung to body weight ratio (LBWR), formal airway morphometry or DNA/protein content. Results In total 983 articles were identified. Following abstract review, 96 articles were assessed by two authors in agreement with a third for eligibility. Of these, 43 were included in the final analysis. The median number of study quality checklist items (maximum 10) scored was 4 (IQ range: 2-5). Thirty (69.8%) of studies were in the nitrofen rat. The majority were treated with vitamins or glucocorticoids. Single studies reported some improvement in lung morphology with alternative therapies. It was impossible to identify a pattern in animal model selection or creation, mode, time point or duration of treatment and readouts. Only one study reported a sample size calculation. Conclusion Comparison in pre-clinical studies in CDH is challenging due to methodological variation. Agreed standardized methods need to be applied in future investigation of new medical therapies.
Collapse
Affiliation(s)
- Mary Patrice Eastwood
- Department of Development and Regeneration, Cluster Organ Systems, Faculty of Medicine, Katholieke Universiteit Leuven, Leuven, Belgium
| | - Francesca Maria Russo
- Department of Development and Regeneration, Cluster Organ Systems, Faculty of Medicine, Katholieke Universiteit Leuven, Leuven, Belgium
| | - Jaan Toelen
- Department of Development and Regeneration, Cluster Organ Systems, Faculty of Medicine, Katholieke Universiteit Leuven, Leuven, Belgium.,Department of Paediatrics, UZ Leuven, KU Leuven, Belgium
| | - Jan Deprest
- Department of Development and Regeneration, Cluster Organ Systems, Faculty of Medicine, Katholieke Universiteit Leuven, Leuven, Belgium.,Department of Obstetrics and Gynaecology, Fetal Medicine Unit, UZ Leuven, Leuven, Belgium
| |
Collapse
|
5
|
Sakai K, Kimura O, Furukawa T, Fumino S, Higuchi K, Wakao J, Kimura K, Aoi S, Masumoto K, Tajiri T. Prenatal administration of neuropeptide bombesin promotes lung development in a rat model of nitrofen-induced congenital diaphragmatic hernia. J Pediatr Surg 2014; 49:1749-52. [PMID: 25487476 DOI: 10.1016/j.jpedsurg.2014.09.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/23/2014] [Accepted: 09/05/2014] [Indexed: 12/19/2022]
Abstract
BACKGROUND/PURPOSE Fetal medical treatment to improve lung hypoplasia in congenital diaphragmatic hernia (CDH) has yet to be established. The neuropeptide bombesin (BBS) might play an important role in lung development. The present study aims to determine whether prenatally administered BBS could be useful to promote fetal lung development in a rat model of nitrofen-induced CDH. METHODS Pregnant rats were administered with nitrofen (100mg) on gestation day 9.5 (E9.5). BBS (50mg/kg/day) was then daily infused intraperitoneally from E14, and fetal lungs were harvested on E21. The expression of PCNA was assessed by both immunohistochemical staining and RT-PCR to determine the amount of cell proliferation. Lung maturity was assessed as the expression of TTF-1, a marker of alveolar epithelial cell type II. RESULTS The lung-body-weight ratio was significantly increased in CDH/BBS(+) compared with CDH/BBS(-) (p<0.05). The number of cells stained positive for PCNA and TTF-1 was significantly decreased in CDH/BBS(+) compared with CDH/BBS(-) (p<0.01). The TTF-1 mRNA expression levels were significantly decreased in CDH/BBS(+) compared with CDH/BBS(-) (p<0.05). CONCLUSIONS Prenatally administered BBS promotes lung development in a rat model of nitrofen-induced CDH. Neuropeptide BBS could help to rescue lung hypoplasia in fetal CDH.
Collapse
Affiliation(s)
- Kohei Sakai
- Department of Pediatric Surgery, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan.
| | - Osamu Kimura
- Department of Pediatric Surgery, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Taizo Furukawa
- Department of Pediatric Surgery, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Shigehisa Fumino
- Department of Pediatric Surgery, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Koji Higuchi
- Department of Pediatric Surgery, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Junko Wakao
- Department of Pediatric Surgery, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Koseki Kimura
- Department of Pediatric Surgery, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Shigeyoshi Aoi
- Department of Pediatric Surgery, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Kouji Masumoto
- Department of Pediatric Surgery, Faculty of Medicine, University of Tsukuba, Tsukuba, Japan
| | - Tatsuro Tajiri
- Department of Pediatric Surgery, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| |
Collapse
|
6
|
Emmerton-Coughlin HMA, Martin KK, Chiu JSS, Zhao L, Scott LA, Regnault TRH, Bütter A. BMP4 and LGL1 are Down Regulated in an Ovine Model of Congenital Diaphragmatic Hernia. Front Surg 2014; 1:44. [PMID: 25593968 PMCID: PMC4286986 DOI: 10.3389/fsurg.2014.00044] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2014] [Accepted: 10/27/2014] [Indexed: 12/05/2022] Open
Abstract
Background/Purpose: The molecular pathophysiology of lung hypoplasia in congenital diaphragmatic hernia (CDH) remains poorly understood. The Wnt signaling pathway and downstream targets, such as bone morphogenetic proteins (BMP) 4 and other factors such as late gestation lung protein 1 (LGL1), are essential to normal lung development. Nitrofen-induced hypoplastic CDH rodent lungs demonstrate down regulation of the Wnt pathway including BMP4 and reduced LGL1 expression. The aim of the current study was to examine the molecular pathophysiology associated with a surgically induced CDH in an ovine model. Methods: Left thoracotomy was performed at 80 days in 14 fetal sheep; CDH was created in seven experimental animals. Lungs were harvested at 136 days (term = 145 days). Lung weight (LW) and mean terminal bronchiole density (MTBD) were measured to determine the degree of pulmonary hypoplasia. Quantitative real time PCR was undertaken to analyze Wnt2, Wnt7b, BMP4, and LGL1 mRNA expression. Results: Total LW was decreased while MTBD was increased in the CDH group (p < 0.05), confirming pulmonary hypoplasia. BMP4 and LGL1 mRNA was significantly reduced in CDH lungs (p < 0.05). Wnt2 mRNA was decreased, although not significantly (p < 0.06). Conclusion: For the first time, down regulation of BMP4 and LGL1 are reported in an ovine CDH model. In contrast to other animal models, these changes are persistent to near term. These findings suggest that mechanical compression from herniated viscera may play a more important role in causing pulmonary hypoplasia in CDH, rather than a primary defect in lung organogenesis.
Collapse
Affiliation(s)
| | - K Kathryn Martin
- Division of General Surgery, London Health Sciences Centre, The University of Western Ontario , London, ON , Canada
| | - Jacky S S Chiu
- Department of Obstetrics and Gynaecology, London Health Sciences Centre, The University of Western Ontario , London, ON , Canada
| | - Lin Zhao
- Department of Obstetrics and Gynaecology, London Health Sciences Centre, The University of Western Ontario , London, ON , Canada
| | - Leslie A Scott
- Division of Pediatric Surgery, Children's Hospital, The University of Western Ontario , London, ON , Canada
| | - Timothy R H Regnault
- Department of Obstetrics and Gynaecology, London Health Sciences Centre, The University of Western Ontario , London, ON , Canada ; Children's Health Research Institute, The University of Western Ontario , London, ON , Canada ; Lawson Health Research Institute, The University of Western Ontario , London, ON , Canada
| | - Andreana Bütter
- Division of Pediatric Surgery, Children's Hospital, The University of Western Ontario , London, ON , Canada ; Lawson Health Research Institute, The University of Western Ontario , London, ON , Canada
| |
Collapse
|
7
|
Ruttenstock EM, Doi T, Dingemann J, Puri P. Prenatal administration of retinoic acid upregulates connective tissue growth factor in the nitrofen CDH model. Pediatr Surg Int 2011; 27:573-7. [PMID: 21258935 DOI: 10.1007/s00383-010-2833-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE Recent studies have suggested that retinoids may be involved in the molecular mechanisms of pulmonary hypoplasia (PH) in congenital diaphragmatic hernia (CDH). Connective tissue growth factor (CTGF) plays a key role in foetal lung development and remodelling during later gestation. CTGF knockout mice exhibit PH with similar characteristics to the human and nitrofen-induced PH. Prenatal administration of retinoic acid (RA) has been shown to stimulate alveologenesis in nitrofen-induced PH. In vitro studies have revealed that RA can induce CTGF gene expression. We hypothesized that pulmonary gene expression of CTGF is downregulated during the later stages of lung development, and that prenatal administration of RA upregulates CTGF in the nitrofen CDH model. METHODS Pregnant rats were exposed to either olive oil or nitrofen on day 9 (D9) of gestation. RA was given intraperitoneally on D18, D19 and D20. Foetuses were harvested on D21 and divided into control, CDH, control + RA and CDH + RA group. Pulmonary CTGF gene and protein expression levels were determined using RT-PCR and immunohistochemistry. RESULTS On D21, CTGF relative mRNA expression levels were significantly downregulated in CDH group compared to controls. After RA treatment, expression levels of CTGF were significantly upregulated in CDH + RA and control + RA compared to the CDH group. Immunohistochemical studies confirmed these results. CONCLUSION Downregulation of pulmonary CTGF gene and protein expression during later stages of lung development may interfere with normal alveologenesis in the nitrofen CDH model. Upregulation of CTGF pulmonary gene expression after prenatal RA treatment may promote lung growth by promoting alveologenesis in the nitrofen-induced CDH model.
Collapse
MESH Headings
- Animals
- Connective Tissue Growth Factor/biosynthesis
- Connective Tissue Growth Factor/drug effects
- Connective Tissue Growth Factor/genetics
- Disease Models, Animal
- Female
- Gene Expression Regulation, Developmental/drug effects
- Hernia, Diaphragmatic/chemically induced
- Hernia, Diaphragmatic/genetics
- Hernia, Diaphragmatic/prevention & control
- Hernias, Diaphragmatic, Congenital
- Immunohistochemistry
- Phenyl Ethers/toxicity
- Pregnancy
- Pregnancy, Animal
- RNA, Messenger/genetics
- Rats
- Rats, Sprague-Dawley
- Reverse Transcriptase Polymerase Chain Reaction
- Tretinoin/administration & dosage
- Up-Regulation/drug effects
Collapse
|