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Plasma Citrulline Concentration as a Marker of Crohn's Disease Activity
AGA Abstracts
exam. The agreement between endoscopic and histologic scores was assessed using Spearman correlation analysis (r). Results: We included 120 exams in 82 asymptomatic patients. In a per-patient analysis (accounting for multiple exams in a single patient), the prevalence of any endoscopic activity (score>0) was 31.7% and the prevalence of any histologic activity (score >1) was 34.2%. Using a “clinically meaningful” threshold of endoscopic severity of ≥2 the prevalence of activity was 17.1%. Only 3.3% of exams in these asymptomatic patients had severe endoscopic activity. Agreement between endoscopic activity and histologic activity was assessed in per segment analysis (r=0.54). Sub-clinical inflammation was more frequently seen in the sigmoid and rectum than in other involved segments, and the rectum was the most frequent segment with moderate or severe activity. Conclusions: A considerable number of asymptomatic UC patients have endoscopic or histologic disease activity found during routine surveillance colonoscopy, and this activity is most often in the distal colon. These findings have significant implications for future mucosal-healing-based treatment algorithms.
status may also increase citrulline measurements. More studies are needed to further elucidate the role of citrulline as a marker of disease activity in patients with CD. Su1185 Disease Activity Assessment of Murine DSS-Colitis by 18F-FDG-PET/CT Dominik Bettenworth, Stefan Reuter, Sven Hermann, Steffen Koschmieder, Tobias M. Nowacki, Matthias Ross, Wolfram W. Domschke, Jan Heidemann, Andreas Luegering Background and Aims: Pre-clinical evaluation of potential anti-inflammatory substances for the treatment of inflammatory bowel disease (IBD) is usually performed in murine models. Hereby, the disease activity is assessed by the measure of indirect parameters (e.g. body weight loss) or by histological analysis which requires ex vivo preparation and therefore determines the end of trial. The aim of this study was to evaluate the feasibility of non invasive In Vivo 18F-Fluor-Desoxy-Glucose (18F-FDG)-PET/CT for assessment of experimental murine colitis. Methods: Colitis was induced in C57BL/6 WT mice by addition of 3% w/v DSS in drinking water for 6 days. The course of colitis was monitored by daily measurements of weight loss and blinded histological scoring of colonic changes at the end of the trial. 18F-FDG was injected into a tail vein four hours before each PET/CT scan. 18FFDG-uptake was calculated from a volume of interest (VOI) manually traced around defined reagions of the colon on reconstructed images (proximal colon vs. distal colon vs. rectum). Mean 18F-FDG-uptake of the colon was calculated by the ratio of total counts and volume. Alterations found within joints were characterized by NACE (naphthol AS-D chloroacetate esterase) and HE-staining. Mucosal neutrophil granulocytes were detected by Gr-1 immunhistochemistry. In addition, FACS analysis of bone marrow cells was performed. Results: At day 4 and day 7 after induction of colitis, 18F-FDG uptake was significantly increased (270%±21 and 200%±18; p<0.05). PET-CT also allowed regional quantification of intestinal inflammation. 18F-FDG-uptake peaked in the distal colon when compared to the proximal colon and rectum (247%±37 vs. 217%±41 vs. 176%±29). Proportions were confirmed by ex vivo measurement of colonic 18F-FDG-activity in PET (477 bq/ml±34.3 vs. 367±53 vs. 305±29). At day seven after induction of colitis, histological changes of the mucosa correlated well with an increased uptake of 18F-FDG (r=0.71). Furthermore, significantly increased 18F-FDG uptake was detected in large joints and bone marrow (+310%±26 vs. control, p<0.05) correlating with intestinal 18F-FDG-uptake (r=0.82). HE- and NACE-staining of bone marrow revealed hypercellular bone marrow with an increase of neutrophil granulocytes in DSS-treated mice but no evidence for active arthritis. FACS-staining for CD11b/Gr+ and B220+ was indicative for induction of immature neutrophils and decreased proliferation of B-lymphocytes. Gr-1 immunhistochemistry revealed increased infiltration of neutrophil granulocytes in the mucosa of DSS-treated mice. Conclusions: PET-CT is a feasible method for repeat objective evaluation of experimental colitis in mice. Disease activity can be locally assessed and additional extraintestinal alterations can be visualized.
Su1183 Disability in Inflammatory Bowel Disease (IBD): Developing Icf Core Sets for Patients With IBD Based on the WHO International Classification of Functioning, Disability and Health Laurent Peyrin Biroulet, Alarcos Cieza, William J. Sandborn, Michaela Coenen, Yehuda Chowers, Toshifumi Hibi, Nenad Kostanjsek, Gerold Stucki, Jean-Frederic Colombel Aim: Disability is the human experience of impaired body functions and structures, activity limitations, and participation restrictions in the interaction with environmental and personal factors. In contrast to other chronic conditions, the impact of IBD on disability remains poorly understood. The ICF integrative model of human functioning and disability provided by WHO makes disability assessment possible. The ICF is a hierarchical code system (4 levels) where various so-called ICF categories represent the basic units of the classification. It includes >1,400 categories classified according to 4 components: Body Functions, Body Structures, Activities and Participation, and Environmental Factors. The aim of this study, conducted by the IPNIC group and funded by Abbott, was to identify the categories of ICF that are affected by IBD as the first step in the development of a disability index. Materials and methods: ICF categories relevant to IBD patients were identified through a formal process developed by WHO: 4 preparatory studies (systematic literature review, patient interviews, expert survey, cross-sectional study) were performed from August 2009 to June 2010. The Comprehensive ICF Core Set that includes all categories affected by IBD and the Brief ICF Core Set that includes the most important of these categories were defined using the results of the preparatory studies during a consensus conference held in June 2010. Results: The systematic literature review identified 153 studies. Six patient focus groups (with a total of 26 patients) were performed in one centre. The expert survey included 125 experts from 37 countries and 7 occupations. The cross-sectional study included 192 patients from 3 centers. These preparatory studies identified 138 second-level ICF categories: 75 for systematic literature review, 38 for patient focus groups, 108 for expert survey, 98 for crosssectional study. As the result of the consensus conference which involved 20 IBD experts from 17 countries, the Comprehensive ICF Core Set included 36 categories (16 categories on Body Functions, 2 on Body Structures, 7 on Activities/Participation, 11 on Environmental Factors) and the Brief ICF Core Set included 19 categories (7 on Body Functions, 2 on Body Structures, 5 on Activities/Participation, 5 on Environmental Factors). Conclusion: Comprehensive and Brief ICF Core Sets for assessing disability in IBD have been defined according to WHO's ICF classification. These ICF Core Sets will be used to develop a disability index that can be used in studies to evaluate the long-term effect of IBD on patient functional status and as a new endpoint in clinical trials aiming at changing the clinical course of the disease.
Su1186 Granulocyte Activation as Measured by CD64 Expression on Pmns Reflects Inflammatory Activity in Inflammatory Bowel Disease Alexander Eser, Christian Primas, Pavol Papay, Sonja Brehovsky, Cornelia Lichtenberger, Andrea Mikulits, Sieglinde Angelberger, Gottfried Novacek, Harald Vogelsang, Wolfgang Tillinger, Walter Reinisch Background and Aims: CD64, the high affinity immunoglobulin Fc γ receptor I (FcγRI) is up regulated during acute phase reaction on polymorphonuclear neutrophils (PMN). CD64 expression is a sensitive biomarker for bacterial infection. Chronic Inflammatory bowel diseases (IBD) such as Crohn's disease (CD) and ulcerative colitis (UC) are considered to be mediated at least in part by the interaction of gut bacteria with the innate immune system. C-reactive-protein (CRP) and orosomucoid (α1-GP) are commonly used to monitor disease activity in IBD. These were compared to granulocyte activation, as measured by CD64 expression on PMNs. Patients and Methods: We included 70 patients with histologically established diagnosis of Crohn's disease (CD, n=39) and ulcerative colitis (UC, n=31) as well as 7 healthy donors (HD). 27 of CD and 20 of UC patients were classified as having active disease by the use of the Harvey Bradshaw Index for Crohn's disease and partial Mayo score for ulcerative colitis. Bacterial infection was ruled out by standard culture methods. PMNs were stained for CD64/CD45 (QuantiBRITE, BD Biosciences) in whole blood. Quantitative expression was measured by flow cytometry on a FACS Calibur (BD Biosciences). Results: CD64 is found on PMNs of CD and UC patients and healthy donors at a median count of 1954 (range 402 - 29532), 958 (294 - 21492) and 429 (240 - 697) molecules/ cell. A significant correlation of CD64 with CRP (τ= 0. 63, p<0.001) and α1-GP (τ=0.62, p<0.001) in CD and in UC (τ=0.44, p=0.027 for CRP and τ=0.38 p=0.003 for α1-GP) was detected. In active CD (n=27), an increased median CD64 count of 2911 m/cell as compared to inactive disease (n= 12, 707 m/cell) was found (p<0.001). In UC, CD64 was detected at a median density of 1824 and 650 m/cell in active (n=20) and inactive disease (n=11), respectively (p=0.025). Receiver operating curve analysis for the distinction of active and inactive disease yielded a sensitivity and specificity of 93% and 77% for CD64 at a cut off of 1015 m/cell for CD and of 75% and 64% at a cut off of 671 m/cell for UC. Conclusions: CD64 expression on PMNs is well correlated with CRP and α1-GP, established markers of inflammation for IBD. Quantitative assessment of CD64 on PMNs by flow cytometry distinguishes active from in active disease in IBD with excellent sensitivity in CD and with moderate sensitivity in UC. CD64 is thereby implicated as useful biomarker for disease monitoring in Crohn's disease.
Su1184 Plasma Citrulline Concentration as a Marker of Crohn's Disease Activity Imad Elkhatib, Alan L. Buchman Background: Citrulline is a nitrogen end product produced from the intermediary metabolism of glutamine, via the enzymatically-mediated urea cycle, almost exclusively in enterocytes of small intestinal epithelium. Citrulline has been established as a biomarker for functional small bowel enterocyte mass under various clinical scenarios including intestinal surgery, radiation-enteritis, celiac disease and acute rejection following small bowel transplantation. Detecting clinical relapse in patients with Crohn's disease(CD) may be difficult, and current clinical, endoscopic and radiographic methods are often insensitive. We sought to determine whether plasma citrulline was a biomarker for disease activity in patients with CD with the hypothesis that citrulline concentration would be reduced during active disease. Methods: 81 outpatients aged 18-65 years with known CD were studied prospectively . Patients with prior small intestinal resection, or renal or hepatic insufficiency were excluded. CD activity was measured via Harvey-Bradshaw Index (HBI), and was correlated to measured serum citrulline concentration measured simultaneously (ion chromatography). Spearman correlation coefficients were used to assess for an association between the two variables. Subgroup analyses of patients with isolated small intestinal disease and endoscopically or radiologic verified disease activity were also performed. Results: 22 subjects had isolated colonic disease and 59 had small intestinal involvement. 26 of these subjects had concurrent endoscopy and/or computed tomography or magnetic resonance imaging . Based on HBI scores, 32 patients had active disease (HBI =>5) and 49 patients had inactive disease. The mean HBI scores were 4.8 +/- 5.5. Mean plasma citrulline concentrations were mostly normal, and did not vary by activity status for CD patients (active 27.8 ± 8.8, inactive 27.8 ± 11.1, p= 0.991). There was no significant linear association between the ranks of citrulline and ranks of HBI (r=0.012, p = 0.915). Of the 59 patients with isolated small intestinal disease, there was no association between plasma citrulline concentration and the HBI ( r= 0.073, p = 0.583). In addition, there was no difference in plasma citrulline concentrations among those with confirmed inflammation by imaging or endoscopy (confirmed 26.2 ± 11.8; negative 28.0 ± 10.0, independent t-test p = 0.583). Conclusion: Plasma citrulline concentration was not a marker of disease activity in patients with CD in our small study. However, all subjects studied were outpatients and it is possible plasma citrulline concentration may be depressed only in patients with more severe disease or extensive small bowel involvement. Fasting
AGA Abstracts
S-424
exam. The agreement between endoscopic and histologic scores was assessed using Spearman correlation analysis (r). Results: We included 120 exams in 82 asymptomatic patients. In a per-patient analysis (accounting for multiple exams in a single patient), the prevalence of any endoscopic activity (score>0) was 31.7% and the prevalence of any histologic activity (score >1) was 34.2%. Using a “clinically meaningful” threshold of endoscopic severity of ≥2 the prevalence of activity was 17.1%. Only 3.3% of exams in these asymptomatic patients had severe endoscopic activity. Agreement between endoscopic activity and histologic activity was assessed in per segment analysis (r=0.54). Sub-clinical inflammation was more frequently seen in the sigmoid and rectum than in other involved segments, and the rectum was the most frequent segment with moderate or severe activity. Conclusions: A considerable number of asymptomatic UC patients have endoscopic or histologic disease activity found during routine surveillance colonoscopy, and this activity is most often in the distal colon. These findings have significant implications for future mucosal-healing-based treatment algorithms.
status may also increase citrulline measurements. More studies are needed to further elucidate the role of citrulline as a marker of disease activity in patients with CD. Su1185 Disease Activity Assessment of Murine DSS-Colitis by 18F-FDG-PET/CT Dominik Bettenworth, Stefan Reuter, Sven Hermann, Steffen Koschmieder, Tobias M. Nowacki, Matthias Ross, Wolfram W. Domschke, Jan Heidemann, Andreas Luegering Background and Aims: Pre-clinical evaluation of potential anti-inflammatory substances for the treatment of inflammatory bowel disease (IBD) is usually performed in murine models. Hereby, the disease activity is assessed by the measure of indirect parameters (e.g. body weight loss) or by histological analysis which requires ex vivo preparation and therefore determines the end of trial. The aim of this study was to evaluate the feasibility of non invasive In Vivo 18F-Fluor-Desoxy-Glucose (18F-FDG)-PET/CT for assessment of experimental murine colitis. Methods: Colitis was induced in C57BL/6 WT mice by addition of 3% w/v DSS in drinking water for 6 days. The course of colitis was monitored by daily measurements of weight loss and blinded histological scoring of colonic changes at the end of the trial. 18F-FDG was injected into a tail vein four hours before each PET/CT scan. 18FFDG-uptake was calculated from a volume of interest (VOI) manually traced around defined reagions of the colon on reconstructed images (proximal colon vs. distal colon vs. rectum). Mean 18F-FDG-uptake of the colon was calculated by the ratio of total counts and volume. Alterations found within joints were characterized by NACE (naphthol AS-D chloroacetate esterase) and HE-staining. Mucosal neutrophil granulocytes were detected by Gr-1 immunhistochemistry. In addition, FACS analysis of bone marrow cells was performed. Results: At day 4 and day 7 after induction of colitis, 18F-FDG uptake was significantly increased (270%±21 and 200%±18; p<0.05). PET-CT also allowed regional quantification of intestinal inflammation. 18F-FDG-uptake peaked in the distal colon when compared to the proximal colon and rectum (247%±37 vs. 217%±41 vs. 176%±29). Proportions were confirmed by ex vivo measurement of colonic 18F-FDG-activity in PET (477 bq/ml±34.3 vs. 367±53 vs. 305±29). At day seven after induction of colitis, histological changes of the mucosa correlated well with an increased uptake of 18F-FDG (r=0.71). Furthermore, significantly increased 18F-FDG uptake was detected in large joints and bone marrow (+310%±26 vs. control, p<0.05) correlating with intestinal 18F-FDG-uptake (r=0.82). HE- and NACE-staining of bone marrow revealed hypercellular bone marrow with an increase of neutrophil granulocytes in DSS-treated mice but no evidence for active arthritis. FACS-staining for CD11b/Gr+ and B220+ was indicative for induction of immature neutrophils and decreased proliferation of B-lymphocytes. Gr-1 immunhistochemistry revealed increased infiltration of neutrophil granulocytes in the mucosa of DSS-treated mice. Conclusions: PET-CT is a feasible method for repeat objective evaluation of experimental colitis in mice. Disease activity can be locally assessed and additional extraintestinal alterations can be visualized.
Su1183 Disability in Inflammatory Bowel Disease (IBD): Developing Icf Core Sets for Patients With IBD Based on the WHO International Classification of Functioning, Disability and Health Laurent Peyrin Biroulet, Alarcos Cieza, William J. Sandborn, Michaela Coenen, Yehuda Chowers, Toshifumi Hibi, Nenad Kostanjsek, Gerold Stucki, Jean-Frederic Colombel Aim: Disability is the human experience of impaired body functions and structures, activity limitations, and participation restrictions in the interaction with environmental and personal factors. In contrast to other chronic conditions, the impact of IBD on disability remains poorly understood. The ICF integrative model of human functioning and disability provided by WHO makes disability assessment possible. The ICF is a hierarchical code system (4 levels) where various so-called ICF categories represent the basic units of the classification. It includes >1,400 categories classified according to 4 components: Body Functions, Body Structures, Activities and Participation, and Environmental Factors. The aim of this study, conducted by the IPNIC group and funded by Abbott, was to identify the categories of ICF that are affected by IBD as the first step in the development of a disability index. Materials and methods: ICF categories relevant to IBD patients were identified through a formal process developed by WHO: 4 preparatory studies (systematic literature review, patient interviews, expert survey, cross-sectional study) were performed from August 2009 to June 2010. The Comprehensive ICF Core Set that includes all categories affected by IBD and the Brief ICF Core Set that includes the most important of these categories were defined using the results of the preparatory studies during a consensus conference held in June 2010. Results: The systematic literature review identified 153 studies. Six patient focus groups (with a total of 26 patients) were performed in one centre. The expert survey included 125 experts from 37 countries and 7 occupations. The cross-sectional study included 192 patients from 3 centers. These preparatory studies identified 138 second-level ICF categories: 75 for systematic literature review, 38 for patient focus groups, 108 for expert survey, 98 for crosssectional study. As the result of the consensus conference which involved 20 IBD experts from 17 countries, the Comprehensive ICF Core Set included 36 categories (16 categories on Body Functions, 2 on Body Structures, 7 on Activities/Participation, 11 on Environmental Factors) and the Brief ICF Core Set included 19 categories (7 on Body Functions, 2 on Body Structures, 5 on Activities/Participation, 5 on Environmental Factors). Conclusion: Comprehensive and Brief ICF Core Sets for assessing disability in IBD have been defined according to WHO's ICF classification. These ICF Core Sets will be used to develop a disability index that can be used in studies to evaluate the long-term effect of IBD on patient functional status and as a new endpoint in clinical trials aiming at changing the clinical course of the disease.
Su1186 Granulocyte Activation as Measured by CD64 Expression on Pmns Reflects Inflammatory Activity in Inflammatory Bowel Disease Alexander Eser, Christian Primas, Pavol Papay, Sonja Brehovsky, Cornelia Lichtenberger, Andrea Mikulits, Sieglinde Angelberger, Gottfried Novacek, Harald Vogelsang, Wolfgang Tillinger, Walter Reinisch Background and Aims: CD64, the high affinity immunoglobulin Fc γ receptor I (FcγRI) is up regulated during acute phase reaction on polymorphonuclear neutrophils (PMN). CD64 expression is a sensitive biomarker for bacterial infection. Chronic Inflammatory bowel diseases (IBD) such as Crohn's disease (CD) and ulcerative colitis (UC) are considered to be mediated at least in part by the interaction of gut bacteria with the innate immune system. C-reactive-protein (CRP) and orosomucoid (α1-GP) are commonly used to monitor disease activity in IBD. These were compared to granulocyte activation, as measured by CD64 expression on PMNs. Patients and Methods: We included 70 patients with histologically established diagnosis of Crohn's disease (CD, n=39) and ulcerative colitis (UC, n=31) as well as 7 healthy donors (HD). 27 of CD and 20 of UC patients were classified as having active disease by the use of the Harvey Bradshaw Index for Crohn's disease and partial Mayo score for ulcerative colitis. Bacterial infection was ruled out by standard culture methods. PMNs were stained for CD64/CD45 (QuantiBRITE, BD Biosciences) in whole blood. Quantitative expression was measured by flow cytometry on a FACS Calibur (BD Biosciences). Results: CD64 is found on PMNs of CD and UC patients and healthy donors at a median count of 1954 (range 402 - 29532), 958 (294 - 21492) and 429 (240 - 697) molecules/ cell. A significant correlation of CD64 with CRP (τ= 0. 63, p<0.001) and α1-GP (τ=0.62, p<0.001) in CD and in UC (τ=0.44, p=0.027 for CRP and τ=0.38 p=0.003 for α1-GP) was detected. In active CD (n=27), an increased median CD64 count of 2911 m/cell as compared to inactive disease (n= 12, 707 m/cell) was found (p<0.001). In UC, CD64 was detected at a median density of 1824 and 650 m/cell in active (n=20) and inactive disease (n=11), respectively (p=0.025). Receiver operating curve analysis for the distinction of active and inactive disease yielded a sensitivity and specificity of 93% and 77% for CD64 at a cut off of 1015 m/cell for CD and of 75% and 64% at a cut off of 671 m/cell for UC. Conclusions: CD64 expression on PMNs is well correlated with CRP and α1-GP, established markers of inflammation for IBD. Quantitative assessment of CD64 on PMNs by flow cytometry distinguishes active from in active disease in IBD with excellent sensitivity in CD and with moderate sensitivity in UC. CD64 is thereby implicated as useful biomarker for disease monitoring in Crohn's disease.
Su1184 Plasma Citrulline Concentration as a Marker of Crohn's Disease Activity Imad Elkhatib, Alan L. Buchman Background: Citrulline is a nitrogen end product produced from the intermediary metabolism of glutamine, via the enzymatically-mediated urea cycle, almost exclusively in enterocytes of small intestinal epithelium. Citrulline has been established as a biomarker for functional small bowel enterocyte mass under various clinical scenarios including intestinal surgery, radiation-enteritis, celiac disease and acute rejection following small bowel transplantation. Detecting clinical relapse in patients with Crohn's disease(CD) may be difficult, and current clinical, endoscopic and radiographic methods are often insensitive. We sought to determine whether plasma citrulline was a biomarker for disease activity in patients with CD with the hypothesis that citrulline concentration would be reduced during active disease. Methods: 81 outpatients aged 18-65 years with known CD were studied prospectively . Patients with prior small intestinal resection, or renal or hepatic insufficiency were excluded. CD activity was measured via Harvey-Bradshaw Index (HBI), and was correlated to measured serum citrulline concentration measured simultaneously (ion chromatography). Spearman correlation coefficients were used to assess for an association between the two variables. Subgroup analyses of patients with isolated small intestinal disease and endoscopically or radiologic verified disease activity were also performed. Results: 22 subjects had isolated colonic disease and 59 had small intestinal involvement. 26 of these subjects had concurrent endoscopy and/or computed tomography or magnetic resonance imaging . Based on HBI scores, 32 patients had active disease (HBI =>5) and 49 patients had inactive disease. The mean HBI scores were 4.8 +/- 5.5. Mean plasma citrulline concentrations were mostly normal, and did not vary by activity status for CD patients (active 27.8 ± 8.8, inactive 27.8 ± 11.1, p= 0.991). There was no significant linear association between the ranks of citrulline and ranks of HBI (r=0.012, p = 0.915). Of the 59 patients with isolated small intestinal disease, there was no association between plasma citrulline concentration and the HBI ( r= 0.073, p = 0.583). In addition, there was no difference in plasma citrulline concentrations among those with confirmed inflammation by imaging or endoscopy (confirmed 26.2 ± 11.8; negative 28.0 ± 10.0, independent t-test p = 0.583). Conclusion: Plasma citrulline concentration was not a marker of disease activity in patients with CD in our small study. However, all subjects studied were outpatients and it is possible plasma citrulline concentration may be depressed only in patients with more severe disease or extensive small bowel involvement. Fasting
AGA Abstracts
S-424