Simple gas chromatography analysis of faecal butyrate: application to patients at risk of pouchitis

In spite of the fact that pouchitis is the most frequently occurring and troublesome complication found in patients treated by ileo-anal anastomosis for ulcerative colitis, no biological marker currently exists to monitor the outcome of the disease. Since it has been noted faecal butyrate is reduced in patients with pouchitis, we developed a simple gas chromatography method to quantify butyrate in faecal water. This test is based on diethyl ether extraction with the use of methacrylic acid as an internal standard. We demonstrated that butyrate was effectively measured when this technique was applied to eleven patients with ileal-pouch anal anastomosis within the first year after the closure of their ileostomy. We also observed a noticeable reduction in the concentration of butyrate in patients who went on to develop a pouchitis.

Genetic analyses of chromosome 12 loci in Crohn's disease

BACKGROUND AND AIMS

Inflammatory bowel disease (IBD) includes ulcerative colitis and Crohn's disease, both of which are multifactorial diseases involving the interaction of genetic and environmental factors. A region on chromosome 12 centred around the marker locus D12S83 has previously been associated with IBD predisposition. The aim of the study was to investigate this genetic region in an independent panel of European families affected by Crohn's disease.

METHODS

A sample of 95 families with two or more affected relatives and 75 simplex nuclear families were genotyped for 19 microsatellite loci located on chromosome 12. A search for linkage and linkage disequilibrium was performed using non-parametric two point and multipoint analyses with the Analyze and Genehunter packages.

RESULTS

No evidence of linkage or linkage disequilibrium was observed for any of the marker loci, including D12S83 (p=0.35 for the two point linkage test). Multipoint linkage analysis also failed to reveal positive linkage on chromosome 12. Power calculations allowed us to reject the hypothesis that the genetic region of chromosome 12 centred on D12S83 contains a susceptibility locus with a relative risk (lambda(s)) equal to or greater than 2.0 in these families.

CONCLUSION

Failure to detect linkage or linkage disequilibrium in these families suggests that the chromosome 12 locus previously reported to be associated with genetic predisposition to IBD does not play a role in all European family samples. This observation is compatible with heterogeneity in the genetic basis of susceptibility to the disease and/or exposure to various environmental factors among Caucasian families.

Familial and sporadic inflammatory bowel disease: different entities?

The strongest risk factor for developing inflammatory bowel disease (IBD) is having a relative with the disease. Familial IBD may be one homogeneous subgroup, phenotypically different from sporadic IBD. Several observations support a role for familiarity in disease site and behavior, particularly in Crohn's disease (CD), but published findings do not all concur. Early disease onset is often found in children with IBD who have a parent with the disease. Genetic anticipation may explain this finding but other explanations and/or observational biasis are more likely. Location and type may differ between familial and sporadic CD cases: family studies report many cases involving both small bowel and colon, and few cases of colonic disease alone, although such features may be secondary to early age at onset. Most studies found no effect of positive family history on severity and course of CD. In ulcerative colitis (UC), phenotypic differences between familial and sporadic cases appear to be limited, but little data are available for analysis. No difference has been found between familial and sporadic IBD as far as disease markers such as pANCA, ASCA, or intestinal permeability are concerned. In conclusion, the only message available for clinical practice is that the relative risk of IBD in first-degree relatives is increased by a factor of 10-15 compared with the general population. Families should not receive genetic counseling/information about age at onset and disease severity.

Enhanced production of IL-8 in chronic but not in early ileal lesions of Crohn's disease (CD)

Distinct Th1/Th2 patterns have been observed during the evolution of CD. The aim of this study was to compare neutrophil involvement and IL-8 mRNA and protein expression during early recurrent lesions and chronic phases of CD. Twenty-nine patients with CD having ileocolonic resection with anastomosis were studied. Biopsies were obtained during surgery from the non-inflamed ileal mucosa and from chronic ileal lesions. Endoscopic ileal biopsies were also taken from early recurrent ileal lesions occurring 3 months after surgery. Neutrophil counts were performed and mucosal IL-8 levels were evaluated by competitive reverse transcriptase-polymerase chain reaction and immunohistochemistry. Early recurrent ileal lesions were characterized by low neutrophil counts and IL-8 production at the mRNA and protein levels compared with the ileal chronic lesions. The main cellular sources of IL-8 in the early recurrent lesions were neutrophils, while in chronic lesions the majority of IL-8-stained cells were CD3+ T cells and macrophages. These results confirmed that the nature of the inflammatory infiltrate and the expression of cytokine profiles may differ between the acute and chronic phases of CD.

Anti-neutrophil cytoplasmic auto-antibodies (ANCA) in ulcerative colitis (UC): no relationship with disease activity

The relationship between anti-neutrophil cytoplasmic auto-antibodies (ANCA) and disease activity in inflammatory bowel diseases remains controversial. The aim of this study was to highlight the relationship between ANCA presence or titers and disease activity in ulcerative colitis (UC). Three groups of patients with UC were studied: 1) group A included 39 patients who had not undergone colectomy, 2) group B, 43 patients with subtotal colectomy and ileo-rectal anastomosis, 3) group C, 98 patients with proctocolectomy and ileo-anal anastomosis, including 88% with pouchitis and 12% without pouchitis at the time of the study. Determination of ANCA was performed using the standardized indirect immunofluorescence assay. ANCA were positive in 59%, 65%, and 54% of patients from groups A, B, and C, respectively (NS). No relationship between ANCA presence or titers and UC activity could be detected within groups A and B. In group C, 45 of 86 patients (52%) without pouchitis and 8 of 12 patients (67%) with pouchitis, were ANCA positive (NS). These results do not support a relationship between ANCA and UC activity in this cohort of 180 patients.

Impaired contractile response of mesenteric arteries in Crohn's disease

BACKGROUND

Crohn's disease is associated with vascular injury and dysregulation of the intestinal immune system which together can provide disturbance of mesenteric circulation functional properties.

AIM

To evaluate the vascular reactivity of mesenteric arteries from patients with Crohn's disease.

METHODS

Phenylephrine-induced contractions were assessed from 10 patients with Crohn's disease and 8 control organ donors. NG-nitro-L-arginine-methyl-ester (L-NAME) was used to test the presence of inducible NO synthase. Endothelium dependent and independent relaxation was assessed using acetylcholine, bradykinin, calcium ionophore A23187 and sodium nitroprusside.

RESULTS

The contractile response to phenylephrine was significantly decreased in arteries without endothelium from patients with Crohn's disease. Exposure to the NO synthase inhibitor L-NAME restored the contractile response to phenylephrine. Relaxation remained unaltered in both groups.

CONCLUSION

These data provide direct evidence for fading of contraction caused by phenylephrine in Crohn's disease. The restored mesenteric artery tone by a specific NO synthase inhibitor suggests that an increased production for NO in vascular smooth muscle might be responsible of this altered vascular reactivity.

Early vascular changes in Crohn's disease: an endoscopic fluorescence study

BACKGROUND AND STUDY AIMS

Early recurrent lesions occurring after surgery in Crohn's disease may be the result of localized vasculitis. The aim of this study was use fluorescence endoscopy to evaluate the mucosal microcirculation of the neoterminal ileum in relation to endoscopic recurrence in patients who had undergone ileocolonic resection for Crohn's disease.

PATIENTS AND METHODS

Ten patients were prospectively enrolled in an endoscopic follow-up study one year after surgery. Recurrence was assessed using routine and fluorescence endoscopy. Biopsies were taken from fluorescent and nonfluorescent sites to look for inflammation and mucosal vascular lesions using standard histological and immunohistochemical methods.

RESULTS

Endoscopic recurrence was found in eight patients. At fluorescence endoscopy, the mucosa displayed a heterogeneous pattern, with fluorescent areas corresponding to aphthoid ulcerations; fluorescent rims surrounding dark zones, corresponding to stellar deep ulcers; and small bright spots distributed singly in the mucosa, which appeared normal on routine endoscopy. Histology revealed inflammatory changes with evidence of vascular involvement in 79% of the biopsies taken from the fluorescent spots.

CONCLUSIONS

Endoscopic recurrence in Crohn's disease is associated with fluorescent aspects that may reflect vasodilation associated with inflammation, or genuine microvascular lesions. Correlation with the histological findings suggests that these early vascular lesions were secondary to the inflammatory process.

[Peroxisome proliferator-activated receptor (PPAR) gamma: a new target for the treatment of inflammatory bowel disease]

The peroxisome proliferator-activated receptor (PPAR) gamma is highly expressed in the colon mucosa. In vitro, it regulates inflammation.

AIM

To evaluate the anti-inflammatory functions of PPARgamma agonist during a trinitrobenzene sulfonic acid (TNBS)-induced colitis in mice.

METHODS

Colitis was induced in Balb/c mice after intra-rectal administration of TNBS. The intensity of inflammation was assessed 2 and 5 days after colitis induction by macroscopic and histologic scores and by the quantification of colon myeloperoxidase (MPO), IL-1B and TNFalpha mRNA concentrations. The therapeutic role of PPARgamma agonist given by oral gavage was assessed in preventive and treatment modes.

RESULTS

TNBS induced severe macroscopic and histologic lesions, with high mucosal MPO, IL-1B and TNFalpha mRNA concentrations. PPARgamma agonist given preventively or in treatment mode allowed a significant decrease of macroscopic and histologic scores through a normalization of MPO, IL-1B and TNFalpha mRNA concentrations.

CONCLUSION

PPARgamma agonist decreases the intensity of TNBS induced colitis through normalization of IL-1B and TNFalpha expression. PPARgamma agonists may be proposed as new therapeutic agents in inflammatory bowel diseases.

Pouchitis is associated with mucosal imbalance between interleukin-8 and interleukin-10

BACKGROUND

Mucosal lesions of pouchitis are characterized by a neutrophil infiltrate. Interleukin (IL)-8 is the main mediator involved in neutrophil recruitment and is down-regulated by IL-10.

AIM

To look for an imbalance between IL-8 and IL-10 in patients with pouchitis.

PATIENTS/METHODS

18 patients having an ileoanal pouch for ulcerative colitis were studied. Eleven had pouchitis defined by the pouchitis disease activity index of > or =7 points and 7 had no history of pouchitis. Biopsies taken at the site of inflammation or in the normal mucosa were scored for the histologic lesions, the intensity of neutrophil infiltration, and the presence of crypt abscesses. Mucosal IL-8 and IL-10 mRNA were quantified by competitive polymerase chain reaction.

RESULTS

IL-8, IL-10, and IL-10/IL-8 mRNA were similar in patients with or without pouchitis. IL-8 mRNA levels were significantly higher in patients with a histologic score >2 (p = 0.01) and in patients with crypt abscesses (p = 0.01). IL-10/IL-8 mRNA was significantly lower in patients having a histologic score >2 (p = 0.019), a neutrophil infiltration > or =10% (p = 0.013), and crypt abscesses (p = 0.01).

CONCLUSION

Histologic lesions of pouchitis are associated with a mucosal imbalance between IL-8 and IL-10. IL-10 could be proposed as a new treatment for pouchitis.

Pouchitis is associated with mucosal imbalance between interleukin-8 and interleukin-10

BACKGROUND

Mucosal lesions of pouchitis are characterized by a neutrophil infiltrate. Interleukin (IL)-8 is the main mediator involved in neutrophil recruitment and is down-regulated by IL-10.

AIM

To look for an imbalance between IL-8 and IL-10 in patients with pouchitis.

PATIENTS/METHODS

18 patients having an ileoanal pouch for ulcerative colitis were studied. Eleven had pouchitis defined by the pouchitis disease activity index of > or =7 points and 7 had no history of pouchitis. Biopsies taken at the site of inflammation or in the normal mucosa were scored for the histologic lesions, the intensity of neutrophil infiltration, and the presence of crypt abscesses. Mucosal IL-8 and IL-10 mRNA were quantified by competitive polymerase chain reaction.

RESULTS

IL-8, IL-10, and IL-10/IL-8 mRNA were similar in patients with or without pouchitis. IL-8 mRNA levels were significantly higher in patients with a histologic score >2 (p = 0.01) and in patients with crypt abscesses (p = 0.01). IL-10/IL-8 mRNA was significantly lower in patients having a histologic score >2 (p = 0.019), a neutrophil infiltration > or =10% (p = 0.013), and crypt abscesses (p = 0.01).

CONCLUSION

Histologic lesions of pouchitis are associated with a mucosal imbalance between IL-8 and IL-10. IL-10 could be proposed as a new treatment for pouchitis.

Methotrexate in Crohn's disease: long-term efficacy and toxicity

OBJECTIVE

A 16-wk, placebo-controlled trial has recently shown weekly low-dose methotrexate to be an effective treatment for patients with chronically active Crohn's disease. The long-term efficacy and safety of this antimetabolite drug, however, are not yet well established and are assessed in this study.

METHODS

A total of 49 patients with Crohn's disease who were treated with methotrexate for > or =6 months were studied. All patients had been chronically treated with steroids; but at the time of initiation, only 27 were still on steroids. Of the 49 patients, 42 had previously taken azathioprine but were no longer on this drug because of intolerance or failure. Clinical remission was defined as a Harvey-Bradshaw index of <4.

RESULTS

In all, 41 patients achieved complete clinical remission and were maintained on methotrexate for a median of 18 months (range, 7-59 months). In these patients the probabilities of relapse were 29%, 41%, and 48% at 1, 2, and 3 yr, respectively. A higher rate of relapse was observed in women and in patients with ileocolitis. Adverse reactions were recorded in 24 patients, requiring discontinuation of methotrexate in five. A liver biopsy was performed in 11 patients; a mild steatosis was found in five, a slight dilation of the sinusoids in one, a granulomatous hepatitis with a mild portal fibrosis in one, and a slight periportal fibrosis in one patient.

CONCLUSIONS

This study suggests a long-term benefit of maintenance treatment with methotrexate in patients with chronically active Crohn's disease, with side effects that are usually only moderate.

Genotypic analysis of thiopurine S-methyltransferase in patients with Crohn's disease and severe myelosuppression during azathioprine therapy

BACKGROUND & AIMS

Myelosuppression in patients with Crohn's disease (CD) treated with azathioprine has been attributed to low activity of thiopurine S-methyltransferase (TPMT). Allelic variants of the TPMT gene responsible for changes in the enzyme activity have been characterized. We investigated the distribution of mutant alleles associated with TPMT deficiency in patients with CD and myelosuppression during azathioprine/6-mercaptopurine therapy.

METHODS

Forty-one patients with CD were included. They developed leukopenia or thrombocytopenia during azathioprine or 6-mercaptopurine treatment. Polymerase chain reaction-based methods were used to search for mutations associated with TPMT deficiency.

RESULTS

Four patients (10%) had 2 mutant alleles associated with TPMT deficiency, 7 (17%) had 1 mutant allele, and 30 (73%) had no known TPMT mutation. The delay between administration of the drug and occurrence of bone marrow toxicity was less than 1.5 months in the 4 patients with 2 mutant alleles, and ranged from 1 to 18 months in patients with 1 mutant allele and from 0.5 to 87 months in patients with normal genotype.

CONCLUSIONS

Twenty-seven percent of patients with CD and myelosuppression during azathioprine therapy had mutant alleles of the TPMT gene associated with enzyme deficiency. Myelosuppression is more often caused by other factors. Continued monitoring of blood cell counts remains mandatory in patients treated with azathioprine.

Selective expansion of intraepithelial lymphocytes expressing the HLA-E-specific natural killer receptor CD94 in celiac disease

BACKGROUND & AIMS

Celiac disease is a gluten-induced enteropathy characterized by the presence of gliadin-specific CD4(+) T cells in the lamina propria and by a prominent intraepithelial T-cell infiltration of unknown mechanism. The aim of this study was to characterize the subset(s) of intraepithelial lymphocytes (IELs) expanding during active celiac disease to provide insights into the mechanisms involved in their expansion.

METHODS

Flow-cytometric analysis of isolated IELs and/or immunohistochemical staining of frozen sections were performed in 51 celiac patients and 50 controls with a panel of monoclonal antibodies against T-cell and natural killer (NK) receptors. In addition, in vitro studies were performed to identify candidate stimuli for NK receptor expression.

RESULTS

In normal intestine, different proportions of IELs, which were mainly T cells, expressed the NK receptors CD94/NKG2, NKR-P1A, KIR2D/3D, NKp46, Pen5, or CD56. During the active phase of celiac disease, the frequency of CD94(+) IELs, which were mostly alphabeta T cells, was conspicuously increased over controls. In contrast, the expression of other NK markers was not modified. Furthermore, expression of CD94 could be selectively induced in vitro by T-cell receptor activation and/or interleukin 15, a cytokine produced by intestinal epithelial cells.

CONCLUSIONS

The gut epithelium favors the development of T cells that express NK receptors. In active celiac disease, there is a specific and selective increase of IELs expressing CD94, the HLA-E-specific NK receptor that may be related to T-cell receptor activation and/or interleukin 15 secretion.

Virus serology in familial Crohn disease

BACKGROUND

Recent findings that early-in-life virus infections represent a risk factor for Crohn disease, that exacerbations of disease sometimes appear associated with common viral infections, and, in particular, suggestions that Crohn disease may be the result of persistent infection with measles virus prompted serologic studies for antibody to 19 common viruses, Chlamydia psittaci, and Mycoplasma pneumoniae.

METHODS

Sera from 14 affected members of 2 French families with a high frequency of Crohn disease and from age- and sex-matched controls, taken in 1990 and 1992, and from unaffected family members were tested. Complement fixation, enzyme immunoassay, and indirect immunofluorescent tests were used.

RESULTS

There were no significant differences between patients and controls or between affected and unaffected family members of family 2, with the exception that affected siblings carried higher antibody titers for mycoplasma one year and for varicella another year. There were no differences in measles IgM and IgG or mumps IgG antibody levels between patients and controls, or between patients and unaffected family members.

CONCLUSIONS

Serology failed to find evidence of participation by 19 common viruses, C. psittaci, and M. pneumoniae in Crohn disease. The data do not support the hypothesis that persistent measles virus infection causes Crohn disease.

[Cholesterol embolism: unusual cause of small intestine occlusion]

We describe a case of small bowel obstruction secondary to cholesterol crystal embolism in a 83-year-old man. Clinical symptoms were dominated by weight loss and vomiting. Small bowel barrium X-ray displayed a short and unique stricture of the jejunum. Atheromatous embolism was suspected in the presence of an aortic aneurysm. At laparotomy, a 2 cm stricture of jejunum was identified and a 6 cm length segment of small bowel was resected. Pathological features were consistent with cholesterol crystal embolism. The patient did well 3 months after surgery. This observation points out the nonspecific clinical presentation of gastrointestinal cholesterol embolism.

Alpha1-antitrypsin phenotypes and anti-neutrophil cytoplasmic auto-antibodies in inflammatory bowel disease

OBJECTIVES

Alpha1-antitrypsin (alpha1-AT) is encoded by a highly polymorphic gene with over 75 codominantly expressed alleles at the protease inhibitor (Pi) locus classified as normal, deficient, dysfunctional or null. The aim of this study was to determine in patients with inflammatory bowel disease: (i) the prevalence of anti-neutrophil cytoplasmic auto-antibodies (ANCA) and their antigen specificities; (ii) alpha1-AT Pi phenotypes; and (iii) possible associations between ANCA, disease activity and deficient alpha1-AT alleles.

DESIGN

Study of 95 consecutive patients with ulcerative colitis (UC) and 63 patients with Crohn's disease (CD).

METHODS

Diagnosis and disease activity were determined by clinical, endoscopic and histological criteria. ANCA by indirect immunofluorescence (IIF) and Pi phenotyping by isoelectric focusing were performed for all patients. Positive IIF sera were tested in antigen-specific enzyme-linked immunosorbent assay: proteinase 3 (PR3), myeloperoxidase (MPO), lactoferrin (LF), lysozyme, human leucocyte elastase (HLE), cathepsin G and bactericidal/permeability increasing protein (BPI).

RESULTS

Sixty-one patients with UC (64.2%) and only 11 with CD (17.5%) had ANCA (P < 0.001). Antigen specificities were PR3 (7/61), MPO (3/61), LF (6/61), HLE (1/63) and BPI (10/61) in UC, and PR3 (2/11) and BPI (2/11) in CD. Three PiZ alleles were found, matching the prevalence in the normal French control population. No relationship was found between the presence of ANCA, antibody specificity, disease activity and deficient alpha1-AT alleles.

CONCLUSION

ANCA are more frequent in UC than CD and do not correlate with disease activity. ANCA and protease/antiprotease imbalance do not appear to modulate the clinical course of inflammatory bowel disease.

Acute inflammatory intestinal vascular lesions and in situ abnormalities of the plasminogen activation system in Crohn's disease

OBJECTIVES

The distribution of the intestinal vascular lesions and their relation with the fibrinolysis process are poorly known in Crohn's disease (CD). The mediators of the plasminogen activator system, namely urokinase-type plasminogen activator (u-PA), tissue-type plasminogen activator (t-PA) and plasminogen activator inhibitor type-1 (PAI-1), are a key complex involved in fibrinolysis. The aims of this study were: (1) to further define vascular lesions and their distribution in the intestine; and (2) to study concomitantly the qualitative in situ expression and the levels of u-PA, t-PA and PAI-1 in the ileum of patients with CD.

PATIENTS AND METHODS

Histological, immunohistochemical and ultrastructural studies of vascular lesions in the resected ileum of 27 patients with CD were performed and compared with 36 control patients. Levels of u-PA, t-PA and PAI-1 measured by ELISA methods were compared in healthy and inflamed ileal tissues of 17 patients with CD.

RESULTS

Acute vascular lesions involving mainly serosal venules and capillaries were present in 63% of patients with CD vs 3/36 controls and were associated with PAI-1 expression. They were prominent on the mesenteric border beneath macroscopically normal mucosa. In contrast, chronic vascular lesions were present in all layers beneath mucosal ulcerations, where a significant increase of PAI-1 levels was found.

CONCLUSIONS

These results suggest that vascular involvement associated with abnormalities of PAI-1 expression is an early and widespread event in CD. Their prominence on the mesenteric border might explain the characteristic location of CD ulceration along the mesenteric margin.

Peroxisome proliferator-activated receptor gamma is induced during differentiation of colon epithelium cells

Peroxisome proliferator-activated receptor gamma (PPARgamma), a fatty acid-activated nuclear receptor, is implicated in adipocyte differentiation and insulin sensitisation. In view of the association of dietary fat intake and bowel disease, the expression of PPARgamma in rodent and human intestine was studied. Expression of PPARgamma mRNA was examined by Northern blot hybridisation, RNase protection, and/or competitive RT-PCR assays, whereas PPARgamma protein levels were evaluated by immunoblotting and immunohistochemistry. PPARgamma mRNA and protein were abundantly expressed in colon relative to the small intestine both in rodents and in man. Interestingly, expression of PPARgamma was primarily localised in the more differentiated epithelial cells in the colon. The level of expression of PPARgamma in colon was similar to the levels seen in adipose tissue. Expression of PPARgamma increased from proximal to distal segments of the colon in man. In Caco-2 and HT-29 human adenocarcinoma cells, PPARgamma expression increased upon differentiation, consistent with PPARgamma being associated with a differentiated epithelial phenotype. High-level expression of PPARgamma was observed in the colon, but not in the small intestine, suggesting a potential role of this nuclear receptor in the colon.