Increased insulin-like growth factor and platelet-derived growth factor system in the pyloric muscle in infantile hypertrophic pyloric stenosis.
BACKGROUND
Infantile hypertrophic pyloric stenosis (IHPS) is characterized by hypertrophy of the pyloric muscle. The etiology of IHPS is unknown. The growth of smooth muscle cells (SMC) is regulated by several growth factors. Insulin-like growth factor (IGF) and platelet-derived growth factor (PDGF) act synergistically to stimulate SMC proliferation. The effects of IGF-I and PDGF are mediated via their receptors.


METHODS
Full-thickness muscle biopsy specimens were obtained from eight IHPS patients (age range, 14 to 46 days) at pyloromyotomy and from eight age-matched controls without gastrointestinal disease at autopsy performed within 4 hours after death. Indirect three-step immunohistochemistry was performed using anti-IGF-I, IGF-I receptor alpha (IGF-IR alpha), IGF-IR beta, PDGF-BB and PDGF receptor (PDGF-R) antibodies and visualized by peroxidase staining.


RESULTS
The most striking difference between tissues from IHPS patients and controls was the marked increase in IGF-I, IGF-IR alpha, IGF-IR beta and PDGF-R in the hypertrophic circular muscle layer, and, to a lesser degree, in the longitudinal muscle in pyloric stenosis.


CONCLUSIONS
The findings suggest that the upregulated local IGF and PDGF systems may play a role in the development of pyloric muscle hypertrophy in IHPS.
Ohshiro
K
K
Children's Research Centre, Our Lady's Hospital for Sick Children, Dublin, Ireland.
Puri
P
P
D000077214:Becaplermin; D001706:Biopsy; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D006984:Hypertrophy; D007124:Immunoenzyme Techniques; D007223:Infant; D007231:Infant, Newborn; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D008297:Male; D010982:Platelet-Derived Growth Factor / Q000378:metabolism*; D020574:Proto-Oncogene Proteins c-sis; D011707:Pyloric Stenosis / Q000378:metabolism*; D011708:Pylorus / Q000378:metabolism / Q000473:pathology
D010982:Platelet-Derived Growth Factor; D020574:Proto-Oncogene Proteins c-sis; D000077214:Becaplermin; D007334:Insulin-Like Growth Factor I