Time course of nitric oxide synthase generation after gluten exposure in the rectal mucosa of gluten-sensitive patients

BACKGROUND

Nitric oxide is thought to play an important role in modulating chronic inflammatory responses as well as in immune-mediated inflammation. We reproduced a gluten-mediated mucosal response in the rectum of celiac and control subjects in order to determine the role of inducible and constitutive nitric oxide synthases in the pathogenesis of this process.

MATERIAL

Nine patients with confirmed celiac disease and five healthy controls underwent a long-term rectal gluten challenge (48 h) after an enema of 6 g of crude gluten, and constitutive and inducible nitric oxide synthase activity were determined in rectal biopsies. The histological localization of inducible nitric oxide synthase was determined by immunohistochemistry.

RESULTS

Activity of both isoforms of nitric oxide synthase in control subjects did not change significantly after gluten instillation. In celiac patients, constitutive nitric oxide synthase on rectal mucosa also showed no significant changes after challenge with gluten. Inducible nitric oxide synthase isoform exhibited a modest increase 4 h after gluten instillation in celiac patients (mean increase 35% compared with baseline levels) but, 8 h after challenge, generation of iNO synthase was significantly higher: 54% more than pre-challenge production (P < 0.05) and higher than control values (P < 0.05). Inducible nitric oxide synthase staining was mostly localized in mononuclear cells of the epithelium and the lamina propria. After gluten instillation, the enhanced staining was mainly localized in subepithelial areas of the lamina propria.

CONCLUSION

Our data suggest a role for nitric oxide, generated by inducible nitric oxide synthase, in the process of rectal mucosa injury by local gluten instillation in sensitized patients. We could not, however, determine if the role of nitric oxide in the ensuing injury of this gluten-induced immune inflammation model is a protective one, or merely a by-product generated by the activation of the inflammatory cells.

Gluten sensitivity in patients with primary biliary cirrhosis

OBJECTIVE

Whereas celiac disease and primary biliary cirrhosis have been reported to coexist in the same patient, the frequency of this relationship has not been clarified. Nowadays, the concept of celiac disease has been extended from that of a severe enteropathy to a broader concept of gluten-driven intestinal immunological response. In this study we assessed features of gluten sensitivity in a cohort of patients with primary biliary cirrhosis.

METHODS

Ten patients with primary biliary cirrhosis were evaluated a mean of 2 yr after diagnosis. The following features of gluten sensitivity were assessed: serum antigliadin and endomysial antibodies, small bowel histology (degree of atrophy and quantitative histological parameters), the presence of the typical celiac HLA genotype (DQ2), and intraepithelial lymphocyte response in the rectal mucosa after local gluten instillation (rectal gluten challenge).

RESULTS

Overall, three patients presented evidence of gluten sensitivity. All three had abnormal titers of antigliadin antibody type IgA and one was positive for endomysial antibody. Two patients had partial villous atrophy. The rectal gluten challenge showed a celiac-like response, evidenced by an increase in intraepithelial lymphocyte infiltration after gluten exposure, in the three patients. The characteristic celiac HLA genotypes (DQA1 0501 and DQB1 0201) were identified in three patients. One of them also exhibited other features of gluten sensitivity. However, despite evidence of gluten intolerance, patients had minimal or no symptoms characteristic of celiac disease.

CONCLUSION

We detected features of gluten sensitivity in a high proportion of patients with primary biliary cirrhosis. Further studies should be performed to elucidate the clinical significance of this association.

Gluten sensitivity in the rectal mucosa of first-degree relatives of celiac disease patients

BACKGROUND/AIMS

Rectal gluten challenge is a simple, sensitive, and specific test of mucosal gluten sensitivity. Our aims in this study were to evaluate gluten sensitivity in a group of relatives of celiac patients and to compare these findings with those obtained on small bowel histology, celiac disease-related serology, and HLA typing.

METHODS

A 4-h rectal gluten challenge was performed with 6 g of crude gluten in saline solution in 29 first-degree relatives, 20 well-diagnosed celiac patients, and 10 subjects in whom celiac disease had been excluded. The number of intraepithelial lymphocytes in pre- and postchallenge frozen rectal biopsies (pan T-cell immunocytochemistry) was quantified by computerized image analysis.

RESULTS

The intraepithelial lymphocyte response after gluten instillation was significantly higher in celiac disease patients (median, 126% increase above the baseline count; 95% confidence interval: 61-213%) compared with control subjects (median, -5%; 95% confidence interval: -29-5%). Using a cut-off of 20% change in intraepithelial lymphocyte count, 14 relatives (48%) showed a celiac-like response. Two of these subjects had partial villous atrophy and increased lymphocyte counts in the small bowel mucosa. One of them also exhibited a positive celiac disease-related serology and the typical celiac human lymphocyte antibody (HLA) DQ2. The remaining 12, and all those relatives with a negative challenge, had normal small bowel mucosa and were negative for antigliadin and endomysial antibodies. The characteristic celiac HLA (DQA1 0501 DQB1 0201 heterodimer) was identified in five relatives with positive challenge (including the patient with more severe mucosal atrophy) but was also present in eight relatives with no evidence of gluten sensitivity in the rectal mucosa.

CONCLUSIONS

Our study characterizes a subgroup of relatives of celiac patients who show mucosal evidence of sensitization after local instillation of gluten in the rectum but who have no other features of celiac disease.

[Synchronous lesions in advanced colorectal cancer]

From jan '82 to jun '91 were done 3701 colonoscopic procedures. Of these, we arrived to cecum in 283 patients (pat) (51.1%) (male: 175 pat; female: 108 pat) in the first six months after the diagnostic of the colorectal cancer (CRC). The localization of the primary CRC was: rectum: 17.7%; left colon: 37.8% and right colon: 44.5%. 105 synchronical polyps (p) were seen in 87 pat (30.7%): 61 pat with 1p; 16 pat with 2 p and 10 pat with 3 p. Adenomas: 50/105 p (56.19%). Early cancer was histologically confirmed in 11/105 p (11/59 p adenomas). The distribution of early were 5/11 in the same colon segment ant 6/11 in the different colon segment. 1 pat has 3 early cancer. Synchronic advanced colorectal cancer (ACC) was seen in 9 pat (M/F = 2/1). All of these in different segments. In conclusion, the high frequency of the premalignant (adenomas) an malignant (early and advanced cancer) lesions, and the high risk of these in different segments of the large bowel, shows the colonoscopy is the most efficient method in the detection of the synchronical lesions of the colorectal cancer.