[Increase of the chondroitin-sulfate proteoglycan, fibronectin and fibroblasts in infantile hypertrophic pyloric stenosis].

INTRODUCTION

Infantile hypertrophic pyloric stenosis (IHPS) consists of hypertrophy of the muscular layer of the pylorus. Its etiology is still unknown. In the last years only few jobs that studied the extracellular matrix (ECM) in the muscular layer in the IHPS have been reported. Our aim was to investigate the expression of two ECM molecules: chondroitin-sulfate proteoglycan (CSPG) and fibronectin (FN), and fibroblasts.

MATERIAL AND METHODS

Full-thickness muscle biopsy specimens were obtained from 33 IHPS patients at pyloromyotomy and 12 controls. Indirect immunohistochemistry was performed using CSPG, FN and fibroblasts monoclonal antibodies. The results were showed by a semiquantitative scale as follows: strong (++), moderate (+), weak (+/-), and absent (-).

RESULTS

We demonstrated that the CSPG immunoreactivity was localized in the connective tissue septa and the expression of FN molecules in the pericellular space. Both molecules were significantly the increased in the muscle layer of the pylorus with IHPS in relation to control pylorus. We also demonstrated a marked increased expression in the number of fibroblasts in the muscle layer of the pylorus with IHPS. Even-though the most striking increase was localized in the septa, we also observed great number of fibroblasts amongst the smooth muscle cells.

CONCLUSIONS

We suggest that IHPS is characterized, not only by the muscle layer hypertrophy, but also by the increase of several ECM molecules, such as CSPG and FN. We also think that the increase of fibroblast could explain the higher expression of both ECM molecules in the muscle layer of pylorus in IHPS.