title: Increased insulin-like growth factor-I mRNA expression in pyloric muscle in infantile hypertrophic pyloric stenosis.
abstract: The etiology of infantile hypertrophic pyloric stenosis (IHPS) is unknown. Insulin-like growth factor-I (IGF-I) is a polypeptide hormone that elicits various biological activities (cellular growth, replication, and differentiation) by binding to its receptors. IGF-I has been suggested to play an important role in both gastrointestinal (GI) maturation and smooth-muscle-cell (SMC) hypertrophy. Full-thickness muscle biopsy specimens were obtained from 8 IHPS patients (age range 14-64 days, mean 28.1 days) at pyloromyotomy and from 8 age-matched controls (15-60 days, mean 33.8 days) without GI disease at autopsy. In-situ hybridization was performed using an IGF-I-specific and digoxigenin (DIG)-labeled oligonucleotide probe and visualized by nitroblue tetrazolium staining. In normal controls, IGF-I mRNA expression was absent or weak in both circular and longitudinal smooth-muscle layers of pyloric muscle. In contrast, the pyloric muscle in IHPS patients demonstrated strong IGF-I mRNA expression in the circular smooth-muscle layer and moderate expression in the longitudinal smooth-muscle layer. The increase in IGF-I mRNA in pyloric muscle in IHPS suggests that SMCs are actively synthesizing IGF-I, contributing to the development of pyloric muscle hypertrophy.
authors.affiliation: Children's Research Centre, Our Lady's Hospital for Sick Children, Dublin, Ireland.
authors.forename: K
authors.initials: K
authors.lastname: Ohshiro
authors.forename: P
authors.initials: P
authors.lastname: Puri
mesh_terms: D005260:Female; D006801:Humans; D006984:Hypertrophy; D017403:In Situ Hybridization; D007223:Infant; D007231:Infant, Newborn; D007334:Insulin-Like Growth Factor I / Q000096:biosynthesis*; D008297:Male; D009130:Muscle, Smooth / Q000378:metabolism / Q000473:pathology; D011707:Pyloric Stenosis / Q000378:metabolism*; D011708:Pylorus / Q000378:metabolism / Q000473:pathology; D012333:RNA, Messenger / Q000378:metabolism*; D017526:Receptor, IGF Type 1 / Q000378:metabolism
chemical_list: D012333:RNA, Messenger; D007334:Insulin-Like Growth Factor I; D017526:Receptor, IGF Type 1