U. Ribeiro et al., EFFECT OF CHAGAS-DISEASE ON NITRIC OXIDE-CONTAINING NEURONS IN SEVERELY AFFECTED AND UNAFFECTED INTESTINE, Diseases of the colon & rectum, 41(11), 1998, pp. 1411-1417
PURPOSE: The pathophysiology of Chagas' disease is incompletely unders
tood. Neuronal nitric oxide has been cited as a candidate neurotransmi
tter responsible for relaxation of the internal anal sphincter. Neuron
al nicotinamide adenine dinucleotide phosphate diaphorase can be used
as a marker for neuronal nitric oxide synthase. This study was designe
d to examine the alterations of the nitric oxide-containing neurons in
the enteric nervous system of the colon of patients who underwent res
ections for advanced megacolon and to compare these specimens with sma
ll-bowel el specimens from the same patients and with specimens from c
ontrol subjects. METHODS: Specimens from resected rectum and extramuco
sal small-bowel biopsy specimens from 11 patients with Chagas megacolo
n but no apparent small-bowel clinical involvement were compared with
the uninvolved colon and jejunum of 10 control patients with colon can
cer. Tissues were fixed in Zamboni solution and evaluated by histochem
istry for nicotinamide adenine dinucleotide phosphate diaphorase-conta
ining neurons. Reactivity was evaluated on a 0 to 4 scale in the longi
tudinal muscle, myenteric plexus, circular muscle, submucosal plexus,
and mucosa. RESULTS: Specimens from control patients showed well-stain
ed myenteric and submucosal neurons and an abundant network of termina
l nerve fibers in the muscle layers. Chagasic specimens had decreased
staining in all layers of the gut. Overall there was a statistically s
ignificant decrease in nicotinamide adenine dinucleotide phosphate dia
phorase-containing neurons. Biopsy specimens from clinically uninvolve
d small bowel of patients with Chagas' disease also showed decreased r
eactivity, but to a lesser degree. CONCLUSIONS: Nicotinamide adenine d
inucleotide phosphate diaphorase activity is decreased in patients wit
h advanced megacolon. The alterations are more relevant in the myenter
ic plexus and the circular muscle. Reactivity is also diminished in th
e clinically uninvolved small bowel, but to a lesser extent.