A possible role of the plasmalemmal cytoskeleton, nitric oxide synthase, and innervation in infantile hypertrophic pyloric stenosis. A confocal laser scanning microscopic study.

In reference to a possible neuropathy in the pathogenesis of infantile hypertrophic pyloric stenosis (IHPS), previous studies have described alterations in peptidergic transmission while others have recently attributed an important role to nitrinergic activity. Little attention has been given to the organization of the extracellular matrix (ECM) and the constituent cytoskeleton and subsarcolemma of the pyloric smooth-muscle cell. To study a possible relationship between neuronal and muscular elements in IHPS, 9 biopsies from patients with IHPS and 5 biopsies of normal pylorus were examined using immunohistochemical techniques with regard to the distribution of nerve cells and fibers (bNOS and PGP 9.5) and the ECM (laminin) and cytoskeleton (talin, vinculin, dystrophin, alpha-smooth iso-actin, desmin) components of the pyloric muscle. Our results showed anti-protein gene product 9.5 and b-nitric oxide synthase immunoreaction respectively reduced or absent in nerve fibers with a positive reaction inside the ganglion cells. An uneven distribution of the ECM component laminin was evident, together with a negative immunoreaction to talin and dystrophin. The imunolocalization of vinculin, alpha-smooth iso-actin, and desmin was similar to the controls. Our findings suggest that there is a close relationship between the nerve and muscle elements in the pathophysiology of IHPS and that non-alteration of some elements of cytoskeleton organization can play an important role in regaining pyloric function after pyloromyotomy.