- Email: [email protected]
Systemic TNF-α Reduction by Blocking IgE-Mediated Cellular Activation
AGA Abstracts
in inflammatory bowel diseases (IBD) specifically at the epithelium. Methods: DSS-colitis mice and human epithelial cell lines were used for gene expression analysis, label free comparative proteomics by mass-spectrometry and cytokines ELISAs. The studies were further substantiated in actual human IBD patient biopsy samples (n=66) collected from Gastroenterlogy department of AIIMS hospital, New Delhi. We also used molecular approaches in primary epithelial cells to study mechanistic details of SUMOylation dependent modulation of IBD. Results: Dextran-sulphate-sodium induced colitis in mice (DSS-mice) resulted in alteration of global SUMOylation with significant lowering of E2-SUMO enzyme, Ubc9. DSS-mice with severely downregulated Ubc9 displayed exacerbation of disease and a distinct colonic SUMO-proteome. Dramatic alteration of SUMOylated forms of key cellular regulators, particularly SUMOylated-Akt1 was observed. Experimental lowering of Ubc9 in various cell lines and murine primary-epithelial cultures led to lowered Akt1 activity and increased proinflammatory signalling. In line with this, a significant lowering of colonic SUMOylation-status was also seen in IBD patient biopsies. Patients with maximum disease indices were accompanied with severely lowered SUMOylation status with reduced SUMOylated-Akt1. Conclusion: Colitis is accompanied with an impaired SUMOylation in intestinal epithelium. Decrease in Ubc9 is a major cause of SUMOylation alteration and onset of inflammation. In human IBD, Ubc9 fine-tunes the epithelial homeostasis via SUMOylation/ phosphorylation dependent activity of Akt1. Overall these results point towards a novel paradigm in IBD-pathophysiology involving SUMOylation and Akt1.
Table 1. Comparison of inflammatory mediators in ulcerative colitis with vs. without Clostridium difficile infection (CDI), and responders vs. nonresponders to CDI treatment
Mo1718 THE SYSTEMIC INFLAMMATORY RESPONSE TO CLOSTRIDIUM DIFFICILE INFECTION (CDI) IN PATIENTS WITH ULCERATIVE COLITIS Julajak Limsrivilai, Krishna Rao, Ryan W. Stidham, Shail M. Govani, Akbar K. Waljee, Andrew R. Reinink, Laura Johnson, Emily Briggs, Peter D. Higgins Background/Aims: There are limited data to define the systemic inflammatory response to Clostridium difficile infection (CDI) in patients with ulcerative colitis (UC). Among UC patients with active symptoms, understanding how inflammatory mediators change in response to CDI may lead to a better ability to differentiate between UC with symptomatic CDI and UC with C. difficile colonization. Methods: We prospectively collected sera from symptomatic UC patients whose stools were tested for toxigenic C. difficile. The patients with positive tests were further categorized into responders to CDI treatment (CDI-R) and non-responders (CDI-NR). Patients with no need for escalation of immunosuppressive agents after complete CDI treatment were considered CDI-R. Circulating inflammatory mediators were measured using an antibody-linked bead array. We compared the results between UC patients with and without CDI, and between CDI-R and CDI-NR groups. Multivariable analyses included logistic regression, principle component analysis (PCA), multivariate analysis of variance (MANOVA), and elastic net regression. Results: We included 117 UC (27 UC with CDI, 90 UC without CDI) patients. There were 14 CDI-R and 8 CDI-NR patients, with 5 indeterminate since they responded to a combination of CDI treatment and escalation of immunosuppressive agents. The results are shown in Table 1. Platelet count, IL-4 and CCL4 were significantly higher in the UC without CDI group compared to the UC with CDI group. Multiple logistic regression to identify the UC with CDI group with a model including CCL4, neutrophil count (ANC), and the interaction between white blood cell count (WBC)/ANC had good performance (area under the receiver operator characteristic curve [AUC] 0.75). Elastic net regression also highlighted IL-4 and IL-8 as potentially important variables predictive of CDI, but the AUC of the model was only 0.66. PCA did not reveal any difference in centroids between groups (non-significant by MANOVA and regression on the first two components). Predictors of responsiveness to CDI therapy in the UC with CDI patients were analyzed. IL-4 and tumor necrotic factor-α were significantly higher in the CDI-R group, but were not significant in multivariate analysis. For commercially available predictors, trends suggested that CDI-R patients had higher procalcitonin, WBC, and hemoglobin (HGB) than the CDI-NR group. Logistic regression models to predict CDI-R including HGB and the interaction between HGB, WBC, and procalcitonin obtained an AUC of 0.85. Conclusion: We observed differences in the circulating inflammatory mediator profiles seen in patients with UC with/without CDI and CDI-R/CDI-NR. Specific inflammatory mediators may help to differentiate a true CDI episode from colonization in UC patients, but larger studies are needed to extend and validate these findings.
AGA Abstracts
Symmetrical data are shown in mean ± SD. Asymmetrical data are shown in median and range.
Mo1719 SYSTEMIC TNF-α REDUCTION BY BLOCKING IGE-MEDIATED CELLULAR ACTIVATION Rachael Hamilton, Vikram Singh, John H. Connor, Thomas Schneider, Francis Farraye, Lisa Ganley-Leal Background: Several cells bearing IgE receptors circulate in the bloodstream, including FcεRI+ basophils and eosinophils and CD23+ B cells and monocytes. The role of IgE and IgE-bearing cells has not been well defined in inflammatory bowel disease (IBD). Recently it has been reported that basophils are elevated in the bloodstream of patients with IBD and may promote IL-17 and IFN-γ production by T cells. Basophils and monocytes have also been shown to secrete TNF-α in response to IgE cross-linking suggesting a potential role of these cells in the pathogenesis of IBD. We are developing ET523, a biologic drug that reduces pathogenic IgE-mediated cellular degranulation by binding free and cell-bound IgE. We sought to determine the effect of ET523 on basophil activation and TNF-α levels in patients with IBD. Methods: Whole blood from each Crohn's Disease (CD) or Ulcerative Colitis (UC) patient was cultured with activating anti-IgE and E. coli LPS separately as well as both with and without ET523. The blood samples were then assessed for IgE mediated cellular activation, TNF-α levels, and IL-8 levels. Cellular activation was assessed by flow cytometry and cytokine levels were measured by ELISA in cell-free supernatants. Results: Anti-IgE cross-linking resulted in an increase in basophil activation as well as TNF-α and IL-8 secretion across both groups. Blood treated with ET523 demonstrated reduced antiIgE mediated cellular activation (Fig. 1; n=6 CD patients and 3 UC patients; P>0.001), as well as TNF-α secretion reduction by approximately 50%. ET523 also reduced basal secretion of TNF-α. Furthermore, basal secretion of IL-8, another biomarker of inflammation, was reduced by ET523, but not anti-IgE mediated induction of IL-8, which may be secreted by other IgE-bearing cells, such as B cells not affected by ET523. Finally, E. coli lipopolysaccharide (LPS) induced the activation of basophils, which was also reduced by ET523. The source of in vivo basophil activation in IBD is not clear, though it is likely due to translocated bacterial products that may react with cell-bound IgE. Conclusions: IgE-mediated basophil (and perhaps other cell types) activation may play a role in the increase in TNF-α in IBD. ET523 appears effective at directly reducing TNF-α secretion by basophils and potentially reducing LPS-induced cellular activation. ET523 may be a potential agent to treat inflammation in patients with IBD.
S-760
AGA Abstracts Figure 1: Percentage of activated IgE+ cells in whole blood. Significant (p<0.001) decrease noted with addition of ET523 when activated by either anti-IgE or E. coli LPS.
Mo1720 UTILITY OF SERUM CYTOKINE ANALYSIS BY LUMINEX-BASED MULTIANALYTE TESTING IN CROHN'S DISEASE FOR DETECTING THERAPEUTIC TARGETS, INCLUDING TNF-α AND IL-12P40 Elizabeth A. Scoville, Margaret M. Allaman, Caroline Brown, Amy Motley, Shannon C. Peyton, Sara N. Horst, Christopher S. Williams, Dawn W. Adams, Dawn Beaulieu, David A. Schwartz, Keith T. Wilson, Lori A. Coburn
Table 1: Serum Cytokines in Crohn's Disease Patients vs Control Subjects. Data are presented as mean ± standard deviation in pg/mL. *P<0.05, **P<0.01, ***P<0.001 vs Control. #P<0.05 vs Inactive CD.
Background: Pro-inflammatory cytokines have been implicated in inflammatory bowel disease pathogenesis, and non-invasive biomarkers are needed to assess disease activity and response to therapy. We have previously shown that 2 serum and 13 colonic tissue cytokines are altered in ulcerative colitis (UC) patients vs control subjects. Our aim was to assess the ability of multiplex Luminex technology to identify differences in the serum cytokine profiles of Crohn's disease (CD) patients. Methods: Serum was prospectively collected from 110 CD and 20 normal control subjects. Demographic information including medication use and clinical disease activity was obtained. Serum cytokines and chemokines were measured by MILLIPLEX bead assay. We screened with a 42-plex panel and based on these results, focused on 30 analytes. We also compared this CD cohort to our previously reported cohort of 109 UC patients. Active disease was defined by Harvey Bradshaw Index ≥ 5 for CD or Mayo score > 2 for UC. We used logistic regression to adjust for age, anti-TNF-α use, and clinically active disease when comparing UC and CD. Results: The majority of our CD patients (91%) were on disease specific therapy with 65% (n=72) on anti-TNF-α agents and 5.5% (n=6) on ustekinumab. Eotaxin-1 (CCL11), TGF-α, G-CSF, GM-CSF, IFN-γ, GRO, IL-10, IL-12p40, IL-17A, IL-5, IL-7, IL-8, IL-9, MIP-1β, and VEGF were increased in CD vs controls (P<0.05). In addition, 14 cytokines were increased in active CD vs control, 16 were increased in inactive CD vs controls, and 2 were increased in active vs inactive CD (P<0.05) (Table 1). After excluding patients on an anti-TNF-α agent, TNF-α was increased in CD vs controls (13.6 ± 11.0 vs 7.0 ± 2.8 pg/mL, P=0.003). CD patients on anti-TNF-α agents had lower TNF-α levels than those who were not (P=0.005). Likewise, CD patients on ustekinumab had lower IL-12p40 levels (69.9 ± 26.6 vs 112.5 ± 156.3 pg/mL), though not statistically significant. When comparing serum cytokines in CD vs UC patients, 13 were significantly different (3 decreased, 10 increased in CD) in unadjusted comparisons (P<0.05). After adjusting for age, anti-TNF-α use, and clinically active disease, 12 serum cytokines were increased in CD vs UC including IL-12p40, EGF, FGF2, eotaxin-1, IFN-α2, MDC (CCL22), IL-13, IL-5, IL-1α, MCP-1, MIP-1α, and VEGF (P<0.05). No cytokine remained significantly decreased in CD vs UC after adjustment. Conclusion: By Luminex assay, multiple serum cytokines were increased in CD patients vs control subjects, and in CD vs UC patients. These alterations, including in therapeutic targets TNF-α and IL-12p40, may have future implications for non-invasive monitoring of disease activity or response to therapy. In addition, differences in CD vs UC suggest differential expression of inflammatory pathways, or may be a result of a more systemic inflammatory response in CD.
Mo1721 SERUM POLYUNSATURATED FATTY ACIDS CORRELATE WITH SERUM CYTOKINES AND CLINICAL DISEASE ACTIVITY IN CROHN'S DISEASE Elizabeth A. Scoville, Dawn W. Adams, Margaret M. Allaman, Amy Motley, Shannon C. Peyton, Sara N. Horst, Christopher S. Williams, Dawn Beaulieu, David A. Schwartz, Keith T. Wilson, Lori A. Coburn Background: Epidemiologic studies have shown an increased prevalence of inflammatory bowel disease (IBD) correlated with higher n6 polyunsaturated fatty acid (PUFA) intake. The mechanism is not fully understood, but it is known that n6 PUFA promote proinflammatory cytokine production via metabolism of arachidonic acid (AA), to leukotriene B4 and thromboxane A2. We have reported differences in serum saturated fatty acid (SFA) and PUFA in ulcerative colitis patients vs controls that correlated with tissue, but not serum, cytokines. Our aim was to identify associations in dietary fatty acid intake, serum fatty acid levels, and serum cytokines in Crohn's disease (CD) patients. Methods: Serum was prospectively collected from 97 CD and 22 normal control subjects. Dietary histories were analyzed using Nutrient Data System for Research software (U. of MN). Active disease was defined by Harvey Bradshaw Index (HBI) ≥ 5. Serum cytokines were measured by Luminex assay. Serum fatty acids were analyzed by gas chromatography and expressed as a percentage of total phospholipids. Results: Dietary histories revealed increased SFA intake in CD patients vs controls (P<0.04), while PUFA intake was not significantly different. Luminex testing revealed that eotaxin-1 (CCL11), TGF-α, G-CSF, GM-CSF, IFN-γ, GRO, IL-10, IL-12p40, IL-17A, IL-5, IL-7, IL-8, IL-9, MIP-1β, and VEGF were increased in CD vs controls (P<0.05). Serum eicosapentaenoic acid (EPA) was increased (1.21 ± 0.74% vs 0.73 ± 0.53%), while AA was decreased (11.90 ± 1.91% vs 13.05 ± 2.26%) in CD vs controls (P<0.05). Serum fatty acid levels were not correlated with dietary intake. Serum total phospholipids, monounsaturated fatty acid (MUFA), n3, oleic acid, EPA, and n3/n6 ratio were significantly higher while serum AA was lower in active CD vs controls (P<0.04). Only EPA was higher in inactive CD vs controls (P=0.02). MUFA and EPA were higher in active vs inactive CD (P<0.05). The following correlated (P<0.05) with HBI assessed as a continuous variable: total phospholipids (r=0.268), MUFA (r=0.287), n3 (r=0.234), n3/n6 ratio (r=0.262), oleic acid (r=0.252), and EPA (r=0.333). Whereas, n6 (r=-0.289, P=0.008) inversely correlated with HBI. Total n3 and EPA were directly correlated, and n6 was inversely correlated with levels of several serum cytokines in CD (Table 1). Conclusions: We identified differences in serum PUFA in CD vs control subjects that did not correlate with dietary intake. Surprisingly, our data indicate that serum n3 fatty acids directly correlate with cytokine biomarkers of inflammation and clinical disease activity. This suggests that there may be defective utilization/metabolism of n3 fatty acids resulting in their accumulation in the serum, accompanied by increased n6 utilization and pro-inflammatory cytokines. Correcting this n3/n6 imbalance may be a potential therapeutic strategy in IBD.
S-761
AGA Abstracts
in inflammatory bowel diseases (IBD) specifically at the epithelium. Methods: DSS-colitis mice and human epithelial cell lines were used for gene expression analysis, label free comparative proteomics by mass-spectrometry and cytokines ELISAs. The studies were further substantiated in actual human IBD patient biopsy samples (n=66) collected from Gastroenterlogy department of AIIMS hospital, New Delhi. We also used molecular approaches in primary epithelial cells to study mechanistic details of SUMOylation dependent modulation of IBD. Results: Dextran-sulphate-sodium induced colitis in mice (DSS-mice) resulted in alteration of global SUMOylation with significant lowering of E2-SUMO enzyme, Ubc9. DSS-mice with severely downregulated Ubc9 displayed exacerbation of disease and a distinct colonic SUMO-proteome. Dramatic alteration of SUMOylated forms of key cellular regulators, particularly SUMOylated-Akt1 was observed. Experimental lowering of Ubc9 in various cell lines and murine primary-epithelial cultures led to lowered Akt1 activity and increased proinflammatory signalling. In line with this, a significant lowering of colonic SUMOylation-status was also seen in IBD patient biopsies. Patients with maximum disease indices were accompanied with severely lowered SUMOylation status with reduced SUMOylated-Akt1. Conclusion: Colitis is accompanied with an impaired SUMOylation in intestinal epithelium. Decrease in Ubc9 is a major cause of SUMOylation alteration and onset of inflammation. In human IBD, Ubc9 fine-tunes the epithelial homeostasis via SUMOylation/ phosphorylation dependent activity of Akt1. Overall these results point towards a novel paradigm in IBD-pathophysiology involving SUMOylation and Akt1.
Table 1. Comparison of inflammatory mediators in ulcerative colitis with vs. without Clostridium difficile infection (CDI), and responders vs. nonresponders to CDI treatment
Mo1718 THE SYSTEMIC INFLAMMATORY RESPONSE TO CLOSTRIDIUM DIFFICILE INFECTION (CDI) IN PATIENTS WITH ULCERATIVE COLITIS Julajak Limsrivilai, Krishna Rao, Ryan W. Stidham, Shail M. Govani, Akbar K. Waljee, Andrew R. Reinink, Laura Johnson, Emily Briggs, Peter D. Higgins Background/Aims: There are limited data to define the systemic inflammatory response to Clostridium difficile infection (CDI) in patients with ulcerative colitis (UC). Among UC patients with active symptoms, understanding how inflammatory mediators change in response to CDI may lead to a better ability to differentiate between UC with symptomatic CDI and UC with C. difficile colonization. Methods: We prospectively collected sera from symptomatic UC patients whose stools were tested for toxigenic C. difficile. The patients with positive tests were further categorized into responders to CDI treatment (CDI-R) and non-responders (CDI-NR). Patients with no need for escalation of immunosuppressive agents after complete CDI treatment were considered CDI-R. Circulating inflammatory mediators were measured using an antibody-linked bead array. We compared the results between UC patients with and without CDI, and between CDI-R and CDI-NR groups. Multivariable analyses included logistic regression, principle component analysis (PCA), multivariate analysis of variance (MANOVA), and elastic net regression. Results: We included 117 UC (27 UC with CDI, 90 UC without CDI) patients. There were 14 CDI-R and 8 CDI-NR patients, with 5 indeterminate since they responded to a combination of CDI treatment and escalation of immunosuppressive agents. The results are shown in Table 1. Platelet count, IL-4 and CCL4 were significantly higher in the UC without CDI group compared to the UC with CDI group. Multiple logistic regression to identify the UC with CDI group with a model including CCL4, neutrophil count (ANC), and the interaction between white blood cell count (WBC)/ANC had good performance (area under the receiver operator characteristic curve [AUC] 0.75). Elastic net regression also highlighted IL-4 and IL-8 as potentially important variables predictive of CDI, but the AUC of the model was only 0.66. PCA did not reveal any difference in centroids between groups (non-significant by MANOVA and regression on the first two components). Predictors of responsiveness to CDI therapy in the UC with CDI patients were analyzed. IL-4 and tumor necrotic factor-α were significantly higher in the CDI-R group, but were not significant in multivariate analysis. For commercially available predictors, trends suggested that CDI-R patients had higher procalcitonin, WBC, and hemoglobin (HGB) than the CDI-NR group. Logistic regression models to predict CDI-R including HGB and the interaction between HGB, WBC, and procalcitonin obtained an AUC of 0.85. Conclusion: We observed differences in the circulating inflammatory mediator profiles seen in patients with UC with/without CDI and CDI-R/CDI-NR. Specific inflammatory mediators may help to differentiate a true CDI episode from colonization in UC patients, but larger studies are needed to extend and validate these findings.
AGA Abstracts
Symmetrical data are shown in mean ± SD. Asymmetrical data are shown in median and range.
Mo1719 SYSTEMIC TNF-α REDUCTION BY BLOCKING IGE-MEDIATED CELLULAR ACTIVATION Rachael Hamilton, Vikram Singh, John H. Connor, Thomas Schneider, Francis Farraye, Lisa Ganley-Leal Background: Several cells bearing IgE receptors circulate in the bloodstream, including FcεRI+ basophils and eosinophils and CD23+ B cells and monocytes. The role of IgE and IgE-bearing cells has not been well defined in inflammatory bowel disease (IBD). Recently it has been reported that basophils are elevated in the bloodstream of patients with IBD and may promote IL-17 and IFN-γ production by T cells. Basophils and monocytes have also been shown to secrete TNF-α in response to IgE cross-linking suggesting a potential role of these cells in the pathogenesis of IBD. We are developing ET523, a biologic drug that reduces pathogenic IgE-mediated cellular degranulation by binding free and cell-bound IgE. We sought to determine the effect of ET523 on basophil activation and TNF-α levels in patients with IBD. Methods: Whole blood from each Crohn's Disease (CD) or Ulcerative Colitis (UC) patient was cultured with activating anti-IgE and E. coli LPS separately as well as both with and without ET523. The blood samples were then assessed for IgE mediated cellular activation, TNF-α levels, and IL-8 levels. Cellular activation was assessed by flow cytometry and cytokine levels were measured by ELISA in cell-free supernatants. Results: Anti-IgE cross-linking resulted in an increase in basophil activation as well as TNF-α and IL-8 secretion across both groups. Blood treated with ET523 demonstrated reduced antiIgE mediated cellular activation (Fig. 1; n=6 CD patients and 3 UC patients; P>0.001), as well as TNF-α secretion reduction by approximately 50%. ET523 also reduced basal secretion of TNF-α. Furthermore, basal secretion of IL-8, another biomarker of inflammation, was reduced by ET523, but not anti-IgE mediated induction of IL-8, which may be secreted by other IgE-bearing cells, such as B cells not affected by ET523. Finally, E. coli lipopolysaccharide (LPS) induced the activation of basophils, which was also reduced by ET523. The source of in vivo basophil activation in IBD is not clear, though it is likely due to translocated bacterial products that may react with cell-bound IgE. Conclusions: IgE-mediated basophil (and perhaps other cell types) activation may play a role in the increase in TNF-α in IBD. ET523 appears effective at directly reducing TNF-α secretion by basophils and potentially reducing LPS-induced cellular activation. ET523 may be a potential agent to treat inflammation in patients with IBD.
S-760
AGA Abstracts Figure 1: Percentage of activated IgE+ cells in whole blood. Significant (p<0.001) decrease noted with addition of ET523 when activated by either anti-IgE or E. coli LPS.
Mo1720 UTILITY OF SERUM CYTOKINE ANALYSIS BY LUMINEX-BASED MULTIANALYTE TESTING IN CROHN'S DISEASE FOR DETECTING THERAPEUTIC TARGETS, INCLUDING TNF-α AND IL-12P40 Elizabeth A. Scoville, Margaret M. Allaman, Caroline Brown, Amy Motley, Shannon C. Peyton, Sara N. Horst, Christopher S. Williams, Dawn W. Adams, Dawn Beaulieu, David A. Schwartz, Keith T. Wilson, Lori A. Coburn
Table 1: Serum Cytokines in Crohn's Disease Patients vs Control Subjects. Data are presented as mean ± standard deviation in pg/mL. *P<0.05, **P<0.01, ***P<0.001 vs Control. #P<0.05 vs Inactive CD.
Background: Pro-inflammatory cytokines have been implicated in inflammatory bowel disease pathogenesis, and non-invasive biomarkers are needed to assess disease activity and response to therapy. We have previously shown that 2 serum and 13 colonic tissue cytokines are altered in ulcerative colitis (UC) patients vs control subjects. Our aim was to assess the ability of multiplex Luminex technology to identify differences in the serum cytokine profiles of Crohn's disease (CD) patients. Methods: Serum was prospectively collected from 110 CD and 20 normal control subjects. Demographic information including medication use and clinical disease activity was obtained. Serum cytokines and chemokines were measured by MILLIPLEX bead assay. We screened with a 42-plex panel and based on these results, focused on 30 analytes. We also compared this CD cohort to our previously reported cohort of 109 UC patients. Active disease was defined by Harvey Bradshaw Index ≥ 5 for CD or Mayo score > 2 for UC. We used logistic regression to adjust for age, anti-TNF-α use, and clinically active disease when comparing UC and CD. Results: The majority of our CD patients (91%) were on disease specific therapy with 65% (n=72) on anti-TNF-α agents and 5.5% (n=6) on ustekinumab. Eotaxin-1 (CCL11), TGF-α, G-CSF, GM-CSF, IFN-γ, GRO, IL-10, IL-12p40, IL-17A, IL-5, IL-7, IL-8, IL-9, MIP-1β, and VEGF were increased in CD vs controls (P<0.05). In addition, 14 cytokines were increased in active CD vs control, 16 were increased in inactive CD vs controls, and 2 were increased in active vs inactive CD (P<0.05) (Table 1). After excluding patients on an anti-TNF-α agent, TNF-α was increased in CD vs controls (13.6 ± 11.0 vs 7.0 ± 2.8 pg/mL, P=0.003). CD patients on anti-TNF-α agents had lower TNF-α levels than those who were not (P=0.005). Likewise, CD patients on ustekinumab had lower IL-12p40 levels (69.9 ± 26.6 vs 112.5 ± 156.3 pg/mL), though not statistically significant. When comparing serum cytokines in CD vs UC patients, 13 were significantly different (3 decreased, 10 increased in CD) in unadjusted comparisons (P<0.05). After adjusting for age, anti-TNF-α use, and clinically active disease, 12 serum cytokines were increased in CD vs UC including IL-12p40, EGF, FGF2, eotaxin-1, IFN-α2, MDC (CCL22), IL-13, IL-5, IL-1α, MCP-1, MIP-1α, and VEGF (P<0.05). No cytokine remained significantly decreased in CD vs UC after adjustment. Conclusion: By Luminex assay, multiple serum cytokines were increased in CD patients vs control subjects, and in CD vs UC patients. These alterations, including in therapeutic targets TNF-α and IL-12p40, may have future implications for non-invasive monitoring of disease activity or response to therapy. In addition, differences in CD vs UC suggest differential expression of inflammatory pathways, or may be a result of a more systemic inflammatory response in CD.
Mo1721 SERUM POLYUNSATURATED FATTY ACIDS CORRELATE WITH SERUM CYTOKINES AND CLINICAL DISEASE ACTIVITY IN CROHN'S DISEASE Elizabeth A. Scoville, Dawn W. Adams, Margaret M. Allaman, Amy Motley, Shannon C. Peyton, Sara N. Horst, Christopher S. Williams, Dawn Beaulieu, David A. Schwartz, Keith T. Wilson, Lori A. Coburn Background: Epidemiologic studies have shown an increased prevalence of inflammatory bowel disease (IBD) correlated with higher n6 polyunsaturated fatty acid (PUFA) intake. The mechanism is not fully understood, but it is known that n6 PUFA promote proinflammatory cytokine production via metabolism of arachidonic acid (AA), to leukotriene B4 and thromboxane A2. We have reported differences in serum saturated fatty acid (SFA) and PUFA in ulcerative colitis patients vs controls that correlated with tissue, but not serum, cytokines. Our aim was to identify associations in dietary fatty acid intake, serum fatty acid levels, and serum cytokines in Crohn's disease (CD) patients. Methods: Serum was prospectively collected from 97 CD and 22 normal control subjects. Dietary histories were analyzed using Nutrient Data System for Research software (U. of MN). Active disease was defined by Harvey Bradshaw Index (HBI) ≥ 5. Serum cytokines were measured by Luminex assay. Serum fatty acids were analyzed by gas chromatography and expressed as a percentage of total phospholipids. Results: Dietary histories revealed increased SFA intake in CD patients vs controls (P<0.04), while PUFA intake was not significantly different. Luminex testing revealed that eotaxin-1 (CCL11), TGF-α, G-CSF, GM-CSF, IFN-γ, GRO, IL-10, IL-12p40, IL-17A, IL-5, IL-7, IL-8, IL-9, MIP-1β, and VEGF were increased in CD vs controls (P<0.05). Serum eicosapentaenoic acid (EPA) was increased (1.21 ± 0.74% vs 0.73 ± 0.53%), while AA was decreased (11.90 ± 1.91% vs 13.05 ± 2.26%) in CD vs controls (P<0.05). Serum fatty acid levels were not correlated with dietary intake. Serum total phospholipids, monounsaturated fatty acid (MUFA), n3, oleic acid, EPA, and n3/n6 ratio were significantly higher while serum AA was lower in active CD vs controls (P<0.04). Only EPA was higher in inactive CD vs controls (P=0.02). MUFA and EPA were higher in active vs inactive CD (P<0.05). The following correlated (P<0.05) with HBI assessed as a continuous variable: total phospholipids (r=0.268), MUFA (r=0.287), n3 (r=0.234), n3/n6 ratio (r=0.262), oleic acid (r=0.252), and EPA (r=0.333). Whereas, n6 (r=-0.289, P=0.008) inversely correlated with HBI. Total n3 and EPA were directly correlated, and n6 was inversely correlated with levels of several serum cytokines in CD (Table 1). Conclusions: We identified differences in serum PUFA in CD vs control subjects that did not correlate with dietary intake. Surprisingly, our data indicate that serum n3 fatty acids directly correlate with cytokine biomarkers of inflammation and clinical disease activity. This suggests that there may be defective utilization/metabolism of n3 fatty acids resulting in their accumulation in the serum, accompanied by increased n6 utilization and pro-inflammatory cytokines. Correcting this n3/n6 imbalance may be a potential therapeutic strategy in IBD.
S-761
AGA Abstracts