R. K. Linskens

Molecular prediction of disease risk and severity in a large Dutch Crohn's disease cohort

Background: Crohn’s disease and ulcerative colitis have a complex genetic background. We assessed the risk for both the development and severity of the disease by combining information from genetic variants associated with inflammatory bowel disease (IBD). Methods: We studied 2804 patients (1684 with Crohn’s disease and 1120 with ulcerative colitis) and 1350 controls from seven university hospitals. Details of the phenotype were available for 1600 patients with Crohn’s disease and for 800 with ulcerative colitis. Genetic association for disease susceptibility was tested for the nucleotide-binding and oligomerisation domain 2 gene (NOD2), the IBD5 locus, the Drosophila discs large homologue 5 and autophagy-related 16-like 1 genes (DLG5 and ATG16L1) and the interleukin 23 receptor gene (IL23R). Interaction analysis was performed for Crohn’s disease using the most associated single nucleotide polymorphism (SNP) for each locus. Odds ratios were calculated in an ordinal regression analysis with the number of risk alleles as an independent variable to analyse disease development and severity. Results: Association with Crohn’s disease was confirmed for NOD2, IBD5, DLG5, ATG16L1 and IL23R. Patients with Crohn’s disease carry more risk alleles than controls (p = 3.85 × 10−22). Individuals carrying an increasing number of risk alleles have an increasing risk for Crohn’s disease, consistent with an independent effects multiplicative model (trend analysis p = 4.25 × 10−23). Patients with Crohn’s disease with a more severe disease course, operations or an age of onset below 40 years have more risk alleles compared to non-stricturing, non-penetrating behaviour (p = 0.0008), no operations (p = 0.02) or age of onset above 40 years (p = 0.028). Conclusion: Crohn’s disease is a multigenic disorder. An increase in the number of risk alleles is associated with an increased risk for the development of Crohn’s disease and with a more severe disease course. Combining information from the known common risk polymorphisms may enable clinicians to predict the course of Crohn’s disease.

Associations with tight junction genes PARD3 and MAGI2 in Dutch patients point to a common barrier defect for coeliac disease and ulcerative colitis.

Background: Coeliac disease (gluten-sensitive enteropathy; GSE) and inflammatory bowel disease (IBD) are common gastrointestinal disorders. Both display enhanced intestinal permeability, initiated by gluten exposure (GSE) or bacterial interactions (IBD). Previous studies showed the association of both diseases with variants in MYO9B, presumably involved in epithelial permeability. Aim: It was hypothesised that genetic variants in tight junction genes might affect epithelial barrier function, thus contributing to a shared pathogenesis of GSE and IBD. Methods: This hypothesis was tested with a comprehensive genetic association analysis of 41 genes from the tight junction pathway, represented by 197 tag single nucleotide polymorphism (SNP) markers. Results: Two genes, PARD3 (two SNPs) and MAGI2 (two SNPs), showed weak association with GSE in a Dutch cohort. Replication in a British GSE cohort yielded significance for one SNP in PARD3 and suggestive associations for two additional SNPs, one each in PARD3 and MAGI2. Joint analysis of the British and Dutch data further substantiated the association for both PARD3 (rs10763976, p = 6.4×10−5; OR 1.23, 95% CI 1.11 to 1.37) and MAGI2 (rs6962966, p = 7.6×10−4; OR 1.19, 95% CI 1.08 to 1.32). Association was also observed in Dutch ulcerative colitis patients with MAGI2 (rs6962966, p = 0.0036; OR 1.26, 95% CI 1.08 to 1.47), and suggestive association with PARD3 (rs4379776, p = 0.068). Conclusions: These results suggest that coeliac disease and ulcerative colitis may share a common aetiology through tight junction-mediated barrier defects, although the observations need further replication.

Thiopurine therapy in inflammatory bowel disease patients: Analyses of two 8-year intercept cohorts†

Background: Thiopurines have proven efficacy in long‐term maintenance therapy of inflammatory bowel disease (IBD). Limited data are available with regard to factors predicting effectiveness and failure of long‐term thiopurine use in IBD patients. Methods: The data in this retrospective study are based on an 8‐year intercept cohort of previous or present thiopurine‐using IBD patients. Both cohorts are assessed by descriptive and statistical analysis aimed at determining thiopurine effectiveness and the variables that are predictive for failure of thiopurine therapy. Results: In all, 363 IBD patients were included (60% female), 63% with Crohns disease and 33% with ulcerative colitis. Overall, thiopurines were continued in 145/363 (40%) and discontinued in 208/363 (57%) patients. The proportion of patients still using thiopurines at 3, 6, 12, 24, and 60 months was 73%, 69%, 63%, 51%, and 42%, respectively. Patients discontinued thiopurines due to adverse events (39%), refractoriness (16%), and ongoing remission / patients request (4%). 6‐methylmercaptopurine (6‐MMP) concentration and 6‐MMP/6‐thioguanine nucleotides (6‐TGN) ratio were significant higher in the failure group. Prolonged continuation of thiopurines was associated with a decreased risk of discontinuation. Conclusions: Azathioprine and 6‐mercaptopurine were considered effective in ≈40% of IBD patients after 5 years of treatment. A quarter of the patients discontinued thiopurines within 3 months, mostly due to adverse events. A high 6‐MMP concentration or 6‐MMP/6‐TGN ratio was associated with therapeutic failure. If thiopurine use was successfully initiated in the first months, its use was usually extended over many years, as long‐term use was associated with continuation of therapy. (Inflamm Bowel Dis 2010)

Predictive value of inflammatory and coagulation parameters in the course of severe ulcerative colitis.

Alterations in markers of coagulation have been found in patients with inflammatory bowel disease. Our aim was to study the predictive value of coagulation and inflammatory parameters in the course of severe ulcerative colitis. Twenty-seven patients were included. The disease course was followed for one year. Sensitivity, specificity, negative predictive value, positive predictive value, and likelihood ratio, as well as the clinical predictive value of laboratory variables were calculated. Inflammatory variables, such as ESR, CRP, and leukocyte and platelet count showed poor diagnostic accuracy. Several coagulation parameters, such as fibrinogen and fibrin(ogen) degradation products, were increased in patients with active ulcerative colitis, whereas coagulation factor XIII was decreased. No significant relationship between clinical course and coagulation parameters was demonstrated, though both inflammatory and coagulation parameters were useful in the assessment of disease activity in patients with active ulcerative colitis.

Hemostatic imbalance in active and quiescent ulcerative colitis.

OBJECTIVE:In healthy conditions, factors inducing or inhibiting coagulation and factors inducing or inhibiting fibrinolysis are in balance. In ulcerative colitis, hypercoagulation is presumed, which may explain part of the clinical features of this disease. Therapy strategies affecting hemostasis may improve the course of ulcerative colitis. This study was conducted to evaluate the balance of coagulation and fibrinolysis in the course of treatment of active ulcerative colitis.METHODS:Patients with active ulcerative colitis were studied by serial determination of markers of the coagulation cascade (thrombin-antithrombin complexes and fibrin degradation products [FbDP]) and the fibrinolytic cascade (fibrinogen degradation products [FgDP]). Parameters of inflammation were also measured (C-reactive protein [CRP], erythrocyte sedimentation rate [ESR], albumin, platelet count, and fibrinogen). Disease activity was assessed by endoscopic and histopathological scores. Follow-up measurement was performed in the course of treatment at the third or fourth month after baseline. Measurements were compared with healthy controls.RESULTS:Thirty-three patients and 22 healthy controls were included. During active ulcerative colitis, inflammatory parameters (CRP, ESR, platelet count) and hemostatic parameters (thrombin-antithrombin complexes, fibrinogen, FgDP, and FbDP) were elevated in comparison with healthy controls. Albumin was decreased and antithrombin-III remained unchanged. During treatment, disease activity decreased significantly endoscopically and histopathologically (p < 0.001). CRP, ESR, platelet count, and fibrinogen also decreased significantly. The hemostatic balance, expressed as the ratio between the plasmin-dependent generation of FgDP and coagulation-dependent generation of FbDP, increased from 0.69 to 1.12 during treatment, mainly because of a decrease of FbDP. In healthy controls, this ratio was 1.33.CONCLUSIONS:The coagulation and fibrinolytic cascades were activated in active ulcerative colitis, with a hemostatic imbalance in favor of coagulation. This hypercoagulability persisted in 20% (7/33) of patients with ulcerative colitis in remission. The decrease of FbDP and the increase in the FgDP/FbDP ratio during reconvalescence of ulcerative colitis showed that the coagulation cascade was more activated than the fibrinolytic cascade in active disease.

Persistent activation of coagulation and fibrinolysis after treatment of active ulcerative colitis

Objective Haemostatic changes may be involved in the pathogenesis and progression of ulcerative colitis. We studied longitudinally inflammatory and haemostatic parameters in patients treated for severe ulcerative colitis. Design and setting We carried out a descriptive study of longitudinal blood measurements in patients with severe ulcerative colitis from one large regional hospital. Methods Nineteen patients with severe ulcerative colitis were assessed by an endoscopic score and a patient score at baseline. Patients were assessed by patient scores during treatment at scheduled intervals. At each visit, inflammatory and haemostatic parameters were determined. Results At baseline, the erythrocyte sedimentation rate, C-reactive protein, leucocyte and granulocyte count, thrombin–antithrombin complexes, prothrombin fragment 1+2, fibrinogen and degradation products of fibrinogen and fibrin were increased in patients when compared with controls, whereas albumin concentration and factor XIII activity were significantly lower. Antithrombin activity was normal. During treatment, the median patient score diminished significantly from 12 to 4.5 points after 2 weeks, decreased further to 4 points after 4 weeks and remained below 4 points throughout the remaining study period. Inflammation parameters returned to within the reference range in two patients after 4 weeks, whereas the coagulation markers prothrombin fragment 1+2 and thrombin–antithrombin complexes returned to normal values after 8 weeks and 24 weeks, respectively. In contrast with markers of inflammation, slightly increased concentrations of the degradation products of both fibrinogen and fibrin were found for almost 1 year, which indicated low-grade activation of coagulation and fibrinolysis. Conclusions These results are compatible with a condition of persistent hypercoagulation in patients with ulcerative colitis who are in clinical remission. Persistent hypercoagulation may contribute to the clinical course of ulcerative colitis.

Azathioprine or mercaptopurine-induced acute pancreatitis is not a disease-specific phenomenon

Aliment Pharmacol Ther 31, 1322–1329

Serum eosinophil cationic protein in active and quiescent ulcerative colitis

Inflammatory bowel disorders are characterized by an accumulation of eosinophilic granulocytes, mast cells, lymphocytes and neutrophilic granulocytes in the intestinal mucosa. The aim of this study was to examine the concentration of eosinophilic granulocytes in the blood of patients during active ulcerative colitis in comparison with patients during remission and apparently healthy control subjects. Besides counting, the activity grade of eosinophilic granulocytes has been studied by estimation of their degranulation product eosinophil cationic protein. Subjects with active ulcerative colitis could be distinguished from patients with quiescent ulcerative colitis by establishment of the eosinophil cationic protein concentration, neutrophilic granulocyte count, erythrocyte sedimentation rate, C-reactive protein and albumin concentration. After two weeks of corticosteroid treatment, serum eosinophil cationic protein concentrations and eosinophil counts in blood were significantly decreased. A decrease in blood eosinophil count was accompanied by a decrease in eosinophil cationic protein concentrations in serum in most subjects with ulcerative colitis. After twelve weeks of corticosteroid administration, serum albumin concentrations were significantly increased, whereas serum concentrations of C-reactive protein were significantly decreased. During treatment with corticosteroids, serum eosinophil cationic protein concentrations and blood eosinophil counts are appropriate laboratory markers to detect the effect of medication in the course of ulcerative colitis.

The relation between coagulation, fibrinolysis and factor XIII levels in ulcerative colitis

Background: Decreased factor XIII (F XIII) levels, the fibrinstabilizing clotting factor, has been described in ulcerative colitis (UC). Consumption of F XIII due to activation of coagulation or fibrinolysis, slow (re)generation of F XIII and gut leakage may account for this decrease. Addition of FXIII may be beneficial in the course of severe UC. We performed laboratory tests concerning coagulation and fibrinolysis in the course of UC to assess their relation with F XIII levels. Methods: A cohort of 20 patients with severe UC was prospectively followed for 12 weeks. At intervals (t=0,2,4,8,12 weeks), symptoms were assessed by a patient score (NEJM 1994, 1841) and blood samples were collected. Endoscopy was performed at baseline and at 12 weeks during which a disease activity score was calculated (J Clin Gastroenterol 1988, 169). This endoscopic score and laboratory findings were related to the patient score (PS) by application of Spearman rank correlation test. All patients were treated with 5-ASA and immunosuppressive therapy. Results: PS strongly correlated with the endoscopic score (r=0.68). A high PS, related with disease activity, was associated with decreasing levels of F XIII (r = -0.37), and increasing CRP (r = 0.52), fibrinogen (r = 0.44), TAT (r = 0.24), and fibrin degradation products (r = 0.30). Plasmin-dependent generation of fibrinogen degradation products was not associated with disease activity (r = -0.09). Low levels of F XIII were strongly associated with TAT (r = -0.65), and CRP (r = 0.52), but not with fibrinogen degradation products (r = -0.09). Conclusions: Activation of coagulation in active UC was demonstrated by positive correlations of PS with TAT and fibrin degradation products. F XIII was strongly correlated with parameters of coagulation, but not with fibrinolysis. We hypothesize that F XIII decrease is due to consumption.