Aberrant fibroblast growth factor receptor 2 signalling in esophageal atresia with tracheoesophageal fistula.
BACKGROUND
Although the pathogenesis of esophageal atresia with tracheoesophageal fistula (EA/TEF) remains unknown, it has been shown that despite its esophageal appearance, the fistula tract originates from respiratory epithelium. The authors now hypothesize that defects in fibroblast growth factor (FGF) signaling contribute to the esophaguslike phenotype of the fistula tract. FGF2R is critical to normal lung morphogenesis and occurs in 2 isoforms (FGF2RIIIb and FGF2RIIIc), each with different ligand-binding specificity. To characterize FGF signaling in the developing EA/TEF, the authors analyzed levels of FGF2R splice variants in experimental EA/TEF.


METHODS
The standard Adriamycin-induced EA/TEF model in rats was used. Individual foregut components from Adriamycin-treated and control embryos were processed for real-time, fluorescence-activated semiquantitative reverse transcriptase polymerase chain reaction on gestational days 12.5 and 13.5.


RESULTS
Both fistula tract and Adriamycin-treated or normal esophagus showed significantly lower levels of FGF2RIIIb than either Adriamycin-treated lung buds (E12.5, P =.02; E13.5, P <.005) or normal lung buds (E12.5, P <.005; E13.5, P <.01). At E13.5, the fistula tract had lower levels of FGF2RIIIc than either treated (P <.01) or normal lung (P <.05).


CONCLUSIONS
Levels of FGF2R in the developing fistula tract resemble that of distal esophagus rather than developing lung. This defect in FGF2RIIIb signaling may account for the nonbranching, esophaguslike phenotype of the fistula, despite its respiratory origin.
Spilde
Troy L
TL
Children's Mercy Hospital Laboratory for Surgical Organogenesis, Kansas City, MO 64108, USA.
Bhatia
Amina M
AM
Mehta
Sheilendra S
SS
Hembree
Mark J
MJ
Preuett
Barry L
BL
Ostlie
Daniel J
DJ
Prasadan
Krishna
K
Li
Zhixing
Z
Snyder
Charles L
CL
Gittes
George K
GK
D000818:Animals; D004317:Doxorubicin / Q000633:toxicity; D004933:Esophageal Atresia / Q000139:chemically induced / Q000196:embryology* / Q000378:metabolism / Q000473:pathology; D005346:Fibroblast Growth Factors / Q000502:physiology; D008168:Lung / Q000196:embryology; D023421:Models, Animal; D009024:Morphogenesis / Q000187:drug effects; D010641:Phenotype; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D017207:Rats, Sprague-Dawley; D051497:Receptor, Fibroblast Growth Factor, Type 2; D017468:Receptors, Fibroblast Growth Factor / Q000172:deficiency* / Q000235:genetics / Q000502:physiology; D015398:Signal Transduction; D014138:Tracheoesophageal Fistula / Q000139:chemically induced / Q000196:embryology* / Q000378:metabolism / Q000473:pathology
D012333:RNA, Messenger; D017468:Receptors, Fibroblast Growth Factor; D005346:Fibroblast Growth Factors; D004317:Doxorubicin; D051497:Receptor, Fibroblast Growth Factor, Type 2