Inflammatory alterations in mesenteric adipose tissue in Crohn's disease

BACKGROUND & AIMS

Abnormalities of fat in the mesentery including adipose tissue hypertrophy and fat wrapping have been long recognized on surgical specimens as characteristic features of Crohn's disease. However, the importance, origin, and significance of the mesenteric fat hypertrophy in this chronic inflammatory disease are unknown. Peroxisome proliferator-activated receptor gamma (PPARgamma) is a crucial factor involved in the homeostasis of adipose tissue, a major source of biologically active mediators.

METHODS

Intra-abdominal fat accumulation was quantified using a magnetic resonance imaging method in patients with Crohn's disease and controls. PPARgamma and inflammatory cytokines synthesized by mesenteric adipose tissues were assessed by quantitative polymerase chain reaction, in situ hybridization, and immunohistochemistry.

RESULTS

In vivo, patients with Crohn's disease have an important accumulation of intra-abdominal fat. This mesenteric obesity, present from the onset of the disease, is associated with overexpression of PPARgamma and tumor necrosis factor (TNF)-alpha, synthesized, at least in part, by adipocytes.

CONCLUSIONS

These results suggest that confined increased PPARgamma mesenteric concentrations could lead to the mesenteric fat hypertrophy, which could actively participate through the synthesis of TNF-alpha in the inflammatory response.

[Excluded rectum during Crohn's diseases: what is the risk of dysplasia?]

OBJECTIVES

An excluded rectum may be at risk of carcinoma in the course of Crohn's disease. Surveillance of patients requires detection of dysplasia. The aim of our study was to determine the frequency of dysplasia from secondary proctectomy specimens in active rectal Crohn's disease.

METHODS

Twenty three patients (13 women and 10 men, median age 38 years) were studied. The median duration of rectal exclusion was four years. Detection of dysplasia relied upon histopathology. Immunohistochemistry with MIB-1 (Ki-67) and anti-p53 (clone DO7) antibodies was performed as well.

RESULTS

Frequency of dysplasia was 30%. This was low grade dysplasia, focally observed in proctectomy specimens. MIB-1 was positive on 46% of dysplastic cells. There was no expression of p53 protein.

CONCLUSIONS

These results must be taken into account for decision of secondary proctectomy, in patients having an excluded rectum for Crohn's disease, when ileorectal anastomosis is not possible. Rectal endoscopic surveillance is advisable with multiple biopsies according to focal distribution of dysplasia.

[Diffuse jejuno-ileitis of Crohn's disease: a separate form of the disease?]

BACKGROUND AND AIMS

Diffuse jejuno-ileitis of Crohn's disease may be a homogeneous clinical subgroup. The aim of this work was to compare the demographic and clinical data at diagnosis and the initial treatments of patients with diffuse jejuno-ileitis of Crohn's disease and to the ones without this localization.

PATIENTS AND METHODS

For demographic and clinical studies, 48 (32M/16F) incident cases of diffuse jejuno-ileitis of Crohn's disease diagnosed between 1988 and 1994 in the EPIMAD register were compared with 96 (48M/48F) controls diagnosed the same year. As far as for the therapeutic management, the 48 incident cases were compared with 48 controls.

RESULTS

Diffuse jejuno-ileitis constituted 3.3% of the total incident cases. Median age at diagnosis was significantly lower (20 vs 23 years, P = 0.01) and an upper digestive involvement was more frequent (56% vs 34%, P = 0.03) in patients with diffuse jejuno-ileitis. These patients were more often treated by total parenteral nutrition (43.8% vs 19.6%, P = 0.01) or azathioprine (50% vs 20.8%, P = 0.005). Azathioprine was also introduced earlier (20.7 vs 40.3 months, P = 0.009). Surgery for resection was less often required in diffuse jejuno-ileitis than in controls (65.2% vs 99.8%, P = 0.02) while more stricturoplasties were performed (52.9% vs 10%, P = 0.003); overall surgical rates did not significantly differ in the 2 groups.

CONCLUSION

Our series suggest that diffuse jejuno-ileitis of Crohn's disease is a subgroup of patients characterized by a young age at diagnosis, with more frequent and earlier requirement for azathioprine.

A controlled trial comparing ciprofloxacin with mesalazine for the treatment of active Crohn's disease. Groupe d'Etudes Thérapeutiques des Affections Inflammatoires Digestives (GETAID)

OBJECTIVE

The aim of this randomized controlled study was to investigate the efficacy of ciprofloxacin compared with mesalazine in treating active Crohn's disease.

METHODS

Patients with a mild to moderate flare-up of Crohn's disease (mean Crohn's Disease Activity Index [CDAI]; 217; range, 160-305) were randomized to receive ciprofloxacin 1 g/day or Pentasa 4 g/day for 6 wk. Complete remission was defined at wk 6 as a CDAI < or = 150 associated with a decrease (delta) in CDAI > 75. Partial remission was defined as a CDAI < or = 150 with 50 < delta CDAI < 75 or a CDAI > 150 with delta CDAI > 50 at wk 6. Group sequential procedure with triangular continuation regions was used to monitor the trial through the difference in complete remission rates, every 20 patients included.

RESULTS

Inclusion of patients was stopped at the second step, i.e., after 40 inclusions, with the conclusion of no difference in complete remission rates between ciprofloxacin- and Pentasa-treated groups. Among the 18 patients taking ciprofloxacin, two decided to stop treatment during the trial and three were considered as treatment failures because of deterioration at wk 3. Among the 22 patients taking mesalazine, one patient was lost to follow-up and eight patients were considered as treatment failures. Complete remission was observed in 10 patients (56%) treated with ciprofloxacin and 12 patients (55%) treated with mesalazine and partial remission was observed in three and one patient, respectively.

CONCLUSIONS

This study suggests that ciprofloxacin 1 g/day is as effective as mesalazine 4 g/day in treating mild to moderate flare-up of Crohn's disease.

Abnormalities in mucin gene expression in Crohn's disease

Alterations in the structure and/or quantity of mucins could alter the barrier function of mucus and play a role in initiating and maintaining mucosal inflammation in Crohn's disease. To investigate the hypothesis of a mucin gene defect in Crohn's disease, we analyzed the expression of the different mucin genes in the ileal mucosa of patients with Crohn's disease and controls. mRNA expression levels were assessed by a quantitative dot blot analysis and compared (i) between healthy and involved ileal mucosa of patients with Crohn's disease and (ii) between healthy mucosa of patients with Crohn's disease and controls. Expression of the different mucin genes was heterogeneous among controls and patients with Crohn's disease, except for MUC6 in controls. Nevertheless, MUC1 mRNA expression was significantly decreased in the involved ileal mucosa of patients with Crohn's disease when compared to the healthy mucosa (p = 0.02). Moreover, the expression levels of MUC3, MUC4, and MUC5B were significantly lower in both healthy and involved ileal mucosa of patients with Crohn's disease compared to controls (p < or = 0.05). The decrease of expression levels of some mucin genes (more particularly MUC3, MUC4, and MUC5B) in both healthy and involved ileal mucosa suggests a primary or very early mucosal defect of these genes in CD.

Abnormalities in mucin gene expression in Crohn's disease

Alterations in the structure and/or quantity of mucins could alter the barrier function of mucus and play a role in initiating and maintaining mucosal inflammation in Crohn's disease. To investigate the hypothesis of a mucin gene defect in Crohn's disease, we analyzed the expression of the different mucin genes in the ileal mucosa of patients with Crohn's disease and controls. mRNA expression levels were assessed by a quantitative dot blot analysis and compared (i) between healthy and involved ileal mucosa of patients with Crohn's disease and (ii) between healthy mucosa of patients with Crohn's disease and controls. Expression of the different mucin genes was heterogeneous among controls and patients with Crohn's disease, except for MUC6 in controls. Nevertheless, MUC1 mRNA expression was significantly decreased in the involved ileal mucosa of patients with Crohn's disease when compared to the healthy mucosa (p = 0.02). Moreover, the expression levels of MUC3, MUC4, and MUC5B were significantly lower in both healthy and involved ileal mucosa of patients with Crohn's disease compared to controls (p < or = 0.05). The decrease of expression levels of some mucin genes (more particularly MUC3, MUC4, and MUC5B) in both healthy and involved ileal mucosa suggests a primary or very early mucosal defect of these genes in CD.

Circulating growth-regulator oncogene alpha contributes to neutrophil priming and interleukin-8-directed mucosal recruitment into chronic lesions of patients with Crohn's disease

Crohn's disease (CD) lesions are characterized by a marked neutrophilic infiltrate associated with enhanced mucosal IL-8, contrasting with low serum IL-8 levels. The aim of this study was to investigate the effects of circulating GROalpha and IL-8 on neutrophil priming and migration. The expression of surface molecules involved in rolling (CD62L, CD15) and firm adhesion (Mac-1 and LFA-1) to endothelial cells was assessed by flow cytometry, while the chemotactic response of PMN to IL-8 and to fMLP was investigated in a Boyden chamber assay. In addition, IL-8 and GROalpha levels were determined by ELISA in plasma samples and in culture supernatants of purified polymorphonuclear neutrophils (PMN) and peripheral blood mononuclear cells (PBMC) from patients with CD and healthy blood donors. This study revealed an upregulation of CD11b (Mac-1) membrane expression on circulating PMN from patients with CD, as assessed by the mean fluorescence intensity which reflects antigen density. Furthermore, an enhanced chemotactic response towards both fMLP and IL-8 of PMN from CD patients was observed. Despite often undetectable levels of circulating IL-8, all plasma samples were positive for GROalpha, with a significant increase in CD patients when compared to donors. In vitro, equivalent concentrations of GROalpha were able to increase the IL-8 driven chemotaxis of PMN. In conclusion, blood PMN from patients with CD showed an enhanced capacity to be recruited into inflammed intestinal mucosa, which could be due to an increased expression of CD11b (Mac-1) as well as an increased chemotactic response toward fMLP or IL-8. This priming effect of PMN in CD may partly occur through elevated circulating GROalpha levels.

Presence of adherent Escherichia coli strains in ileal mucosa of patients with Crohn's disease

BACKGROUND & AIMS

Infectious agents are suspected of being involved in the pathogenesis of Crohn's disease. This study was designed to look for the presence of virulent Escherichia coli strains associated with the ileal mucosa of patients with Crohn's disease.

METHODS

E. coli strains were recovered from resected chronic ileal lesions (n = 20), neoterminal ileum after surgery from patients with (n = 19) and without (n = 11) endoscopic recurrence, and controls (n = 13). Bacterial adhesion was determined in vitro using intestinal cell lines; other associated virulence factors were assessed by DNA hybridization and polymerase chain reaction experiments.

RESULTS

None of the strains harbored any of the virulence factor-encoding genes of E. coli involved in acute enteric diseases. However, mannose-resistant adhesion to differentiated Caco-2 cells was found for 84.6% and 78.9% of the E. coli strains isolated from chronic and early recurrent lesions, respectively, compared with 33% of controls (P < 0.02). In addition, 21.8% of the strains induced a cytolytic effect by synthesis of an alpha-hemolysin.

CONCLUSIONS

E. coli strains isolated from the ileal mucosa of patients with Crohn's disease adhere to differentiated intestinal cells and may disrupt the intestinal barrier by synthesizing an alpha-hemolysin.

Genotypic and phenotypic analysis of the polymorphic thiopurine S-methyltransferase gene (TPMT) in a European population

1. Characterization of allelic variants of the TPMT gene (TPMT) responsible for changes in TPMT activity, and elucidation of the mechanism by which these alleles act, are required because of the clinical importance of this polymorphism for patients receiving thiopurine drugs. 2. We defined the mutational and allelic spectrum of TPMT in a group of 191 Europeans. Using PCR-SSCP, we screened for mutation the entire coding sequence, the exon-intron boundaries, the promoter region and the 3'-flanking region of the gene. Six mutations were detected throughout the ten exons and seven TPMT alleles were characterized. Four of them, TPMT*2, *3A, *3C and *7, harbouring the known mutations, G238C, G460A, A719G or T681G, were nonfunctional and accounted for 0.5, 5.7, 0.8 and 0.3% of the allele totality, respectively. 3. Within the promoter region, six alleles corresponding to a variable number of tandem repeats (VNTR), were identified. VNTR*V4 and *V5a which harbour four or five repeats of a 17-18 bp unit, were the most frequent (55% and 34%, respectively). The other VNTR alleles, having from five to eight repeats, were rarer. 4. The TPMT phenotype was correctly predicted by genotyping for 87% of individuals. A clear negative correlation between the total number of repeats from both alleles and the TPMT activity level was observed, indicating that VNTRs contribute to interindividual variations of TPMT activity. Therefore, additional analysis of the promoter region of TPMT can improve the phenotype prediction rate by genotyping.

[Chronic interstitial nephritis and mesalazine: 3 new cases?]

We report three new cases of chronic interstitial nephritis occurring in two patients with Crohn's disease and one patient with ulcerative colitis treated with mesalazine. In the three cases asymptomatic renal disease was revealed by an increase in serum creatinine which was normal before treatment. Renal biopsy showed features of severe chronic interstitial nephritis. Mesalazine withdrawal and administration of steroids in two cases led to partial improvement of renal function. Mechanism of renal toxicity of mesalazine is unknown. These observations stress the need for monitoring renal function in patients with inflammatory bowel disease treated with mesalazine.

Anti-Saccharomyces cerevisiae mannan antibodies in familial Crohn's disease

OBJECTIVE

Anti-Saccharomyces cerevisiae mannan antibodies (ASCA) are associated with Crohn's disease. The aim of this study was to determine the prevalence of ASCA in families in which at least two members were affected with Crohn's disease.

METHODS

A total of 20 families including two (n=15) or more (n=5) patients with Crohn's disease were tested for ASCA with use of an ELISA method. Overall, 51 affected members, 66 healthy first degree relatives, and 163 healthy control subjects were studied.

RESULTS

ASCA were detected in 35 of 51 (69%) patients with Crohn's disease and in 13 of 66 (20%) healthy relatives versus one of 163 healthy control subjects (p < 0.0001 and p < 0.001). ASCA-positive relatives were distributed in 12 of 20 families. ASCA were present in eight healthy parents and four healthy siblings. The prevalence of ASCA in relatives did not depend on the ASCA status of affected members.

CONCLUSION

ASCA in 20% of healthy first degree relatives of patients with Crohn's disease suggest that these antibodies might be a subclinical marker for Crohn's disease in families. Whether ASCA reflect environmental or genetic factors or a combination of both is unknown.

Similar IL-5, IL-3, and GM-CSF syntheses by eosinophils in the jejunal mucosa of patients with celiac disease and dermatitis herpetiformis

Celiac disease (CD) and dermatitis herpetiformis (DH) are gluten-sensitive diseases with different clinical features that can initiate similar intestinal changes. The flat-destructive stage corresponds to severe lesions involving activated T-cells. However, other inflammatory cells such as eosinophils are also abundant. The mechanisms for the intestinal recruitment of eosinophils in patients with CD and DH remain unknown. Eosinophil recruitment and activation are induced in vitro by three main cytokines: interleukin-3 (IL-3), interleukin-5 (IL-5), and granulocyte-macrophage colony-stimulating factor (GM-CSF). In this study, IL-3, IL-5, and GM-CSF were detected by immunohistochemistry in all patients with CD and DH but not in the control group. By ultrastructural immunogold staining, these three cytokines had the same subcellular localization in the granule matrix of eosinophils. This result suggests that eosinophils may be involved in the immune response at the flat-destructive stage of both CD and DH.

Anti-Saccharomyces cerevisiae mannan antibodies combined with antineutrophil cytoplasmic autoantibodies in inflammatory bowel disease: prevalence and diagnostic role

BACKGROUND

Perinuclear antineutrophil cytoplasmic autoantibodies (pANCA) are a well recognised marker for ulcerative colitis. Antibodies to oligomannosidic epitopes of the yeast Saccharomyces cerevisiae (ASCA) are a new marker associated with Crohn's disease.

AIMS

To assess the value of detecting pANCA and/or ASCA for the diagnosis of ulcerative colitis and Crohn's disease.

METHODS

Serum samples were obtained from 100 patients with Crohn's disease, 101 patients with ulcerative colitis, 27 patients with other miscellaneous diarrhoeal illnesses, and 163 healthy controls. Determination of pANCA and ASCA was performed using the standardised indirect immunofluorescence technique and an ELISA, respectively.

RESULTS

The combination of a positive pANCA test and a negative ASCA test yielded a sensitivity, specificity, and positive predictive value of 57%, 97%, and 92.5% respectively for ulcerative colitis. The combination of a positive ASCA test and a negative pANCA test yielded a sensitivity, specificity, and positive predictive value of 49%, 97%, and 96% respectively for Crohn's disease. Among patients with miscellaneous non-inflammatory bowel disorders, three were ASCA positive and two were pANCA positive. One control was ASCA positive. The presence of ASCA in patients with Crohn's disease was associated with small bowel involvement.

CONCLUSION

ASCA and pANCA are strongly associated with Crohn's disease and ulcerative colitis, respectively. Combination of both tests could help the diagnosis of inflammatory bowel disease.

[Pseudotumor nodular lymphoid hyperplasia of the ileum]

We report a case of pseudotumoral nodular lymphoid hyperplasia of the ileum in an immunocompetent 62-year-old woman. Ileoscopy showed multiple voluminous, soft, pliable, polypoid ileal lesions. Perendoscopic biopsies revealed a florid inflammation of the mucosa, characterised by numerous enlarged follicles with well-developed reactive germinal centres separated by a mixed infiltrate of lymphocytes, plasma cells and eosinophils. Immunohistochemistry showed a polytypic staining for kappa and lambda light-chains in the follicles and between and confirmed the reactive nature of the infiltrate. CT scan of the abdomen disclosed large periileal lymph nodes and a right ileocolectomy was performed. Twelve cases of pseudotumoral nodular lymphoid hyperplasia of the ileum have been reported in the literature in patients older than 25. In all cases, the diagnosis was performed after laparotomy. As shown in our case report, the diagnosis is possible on multiple perendoscopic biopsies.

Evidence of linkage of the inflammatory bowel disease susceptibility locus on chromosome 16 (IBD1) to ulcerative colitis

Crohn's disease (CD) and ulcerative colitis (UC) are inflammatory bowel diseases (IBD) of unknown aetiology which are characterised by chronic inflammation of the gastrointestinal tract. Epidemiological studies suggest the presence of a genetic component in the aetiology of both CD and UC. A susceptibility gene for Crohn's disease has recently been mapped to the pericentromeric region of chromosome 16 (IBD1), and this finding has been replicated in two subsequent studies. Although CD and UC are distinct clinical entities, the fact that both disorders occur in a significant proportion of families with multiple cases of IBD suggests that overlapping sets of susceptibility genes may be involved. We have addressed this question for IBD1 by typing eight microsatellite markers from the locus in 70 kindreds affected with either UC only or with both UC and CD and analysing the data for linkage by both non-parametric and parametric methods. Evidence for linkage was detected in families affected with only UC, with a mean proportion of 0.70 affected sib pairs sharing alleles identical by descent at D16S3136 (p=0.01), and a peak non-parametric linkage score of 2.02 at D16S3120 with the GENEHUNTER program (p=0.02). The estimated sib relative risk attributable to IBD1 in these families was 1.46. Surprisingly, no evidence of linkage was detected in the families affected with both UC and CD (p>0.2). The data suggest that IBD1 may also contribute to susceptibility to ulcerative colitis, and that it is likely to be located in the 12 cM interval between D16S419 and D16S409.

Anticipation in familial Crohn's disease

BACKGROUND

Offspring with a family history of Crohn's disease have an earlier age of onset than their parents. This might be due to genetic anticipation, characterised by earlier and/or more severe disease in subsequent generations.

AIMS

To investigate the possibility of genetic anticipation in affected parent-child pairs with Crohn's disease from France and Belgium.

PATIENTS AND METHODS

In a cohort of 160 multiply affected families with Crohn's disease, 57 parent-first affected child pairs were detected. Clinical characteristics (age at diagnosis, disease extent, and type) of both parents and children were registered and compared.

RESULTS

Children were younger than their parents at diagnosis in 48/57 (84%) pairs. The median age at diagnosis was 16 years younger in children than in parents (p < 0.0001). However, the difference was related to the age at diagnosis in the parents and was not present in 12 parent-child pairs with an early age at diagnosis for the parents. In most cases, disease extent and type were not considered more severe in children than in parents. Parental sex affected neither age at diagnosis nor extent and type of disease in children.

CONCLUSION

Patients in the second affected generation acquire their disease at an earlier time in life in some but not all familial cases of Crohn's disease. Several explanations including genetic anticipation and environmental factors might explain this phenomenon.

[The synovitis-acne-pustulosis-hyperostosis-osteitis (SAPHO) syndrome, a rare extra-digestive manifestation of Crohn's disease. Presentation of 1 case and review of the literature]

We report the case of a 33-year-old man with a severe Crohn's disease since the age of sixteen. He presented with acne and palmoplantar pustulosis associated with a right knee synovitis. Investigations revealed a major axial bone condensation. The association synovitis-acne-pustulosis-hyperostosis-osteitis leaded to the diagnosis of SAPHO syndrome associated with Crohn's disease.