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This supplementary figure describes the effects of DSS administration in TWEAK deficient mice compared to wild type littermates.

Inflammatory bowel disease causes chronic, relapsing intestinal inflammation that can lead to the development of colorectal cancer. Members of the TNF superfamily are key regulators of intestinal inflammation. In particular, TNF-like weak inducer of apoptosis (TWEAK) and its receptor, Fn14, are involved in normal and pathologic intestinal tissue remodeling. In this study, we show that the TWEAK/Fn14 signaling complex plays a protective role during the acute stage of intestinal inflammation and contributes to the prevention of colitis-associated cancer during chronic inflammation through its proapoptotic effects. Colitis was induced in Fn14−/− and Fn14+/+ wild-type littermates by administering 3% dextran sodium sulfate (DSS) for 7 days followed by 2-week recovery; azoxymethane (AOM) administration followed by two cycles of DSS/recovery was used to induce tumors. Reciprocal bone marrow chimeric mice were generated to compare hematopoietic and nonhematopoietic-specific effector tissues. Fn14−/− mice had enhanced susceptibility to colitis compared with Fn14+/+ controls as assessed by endoscopic and histologic inflammatory scores, daily weight loss, and mortality rates during recovery after DSS administration. Bone marrow transfer experiments showed that both hematopoietic and nonhematopoietic components are involved in protection against colitis. Tumor lesions were found in the colons of most Fn14−/− mice, but not Fn14+/+ controls. AOM/DSS administration enhanced susceptibility to tumorigenesis in Fn14−/− mice. Overall, these findings show that Fn14 plays a protective role during the acute stages of intestinal inflammation, and its absence promotes the development of colitis-associated cancer. Cancer Res; 76(22); 6533–42. ©2016 AACR.

This supplementary figure describes the effects of Fn14 antibody neutralization in C57/BL6 mice following induction of DSS colitis..

BACKGROUND: TNF-like cytokine 1A (TL1A) and its functional receptor, death-domain-receptor-3 (DR3), are multifunctional mediators of effector and regulatory immunity. We aimed to evaluate the functional role and therapeutic potential of TL1A/DR3 signaling in Crohn’s disease–like ileitis. METHODS: Ileitis-prone SAMP1/YitFc (SAMP) and TNF(ΔARE/+) mice were rendered deficient for DR3 or TL1A by microsatellite marker-assisted backcrossing. Pathological and immunological characteristics were compared between control and knockout mice, and mucosal immunophenotype was analyzed by Nanostring microarray assay. The therapeutic effect of pharmacological TL1A neutralization was also investigated. RESULTS: DR3 deficiency was associated with restoration of a homeostatic mucosal immunostat in SAMP mice through the regulation of several pro- and anti-inflammatory genes. This led to suppression of effector immunity, amelioration of ileitis severity, and compromised ability of either unfractionated CD4(+) or CD4(+)CD45RB(hi) mucosal lymphocytes to transfer ileitis to severe combined immunodeficient mice recipients. TNF-driven ileitis was also prevented in TNF(ΔARE/+)xDR3(-/-) mice, in association with decreased expression of the pro-inflammatory cytokines TNF and IFN-γ. In contrast to DR3, TL1A was dispensable for the development of ileitis although it affected the kinetics of inflammation, as TNF(ΔARE/+)xTL1A(-/-) demonstrated delayed onset of inflammation, whereas administration of a neutralizing, anti-TL1A antibody ameliorated early but not late TNFΔARE/+ ileitis. CONCLUSION: We found a prominent pro-inflammatory role of DR3 in chronic ileitis, which is only partially mediated via interaction with TL1A, raising the possibility for additional DR3 ligands. Death-domain-receptor-3 appears to be a master regulator of mucosal homeostasis and inflammation and may represent a candidate therapeutic target for chronic inflammatory conditions of the bowel.

Currently several mouse models are considered representative of inflammatory bowel disease (IBD). This review presents recent developments regarding the role of animal models of intestinal inflammation as research tools in IBD.Preclinical studies in animal models of intestinal inflammation have generated novel findings in several areas of IBD research. The combination of chemical and genetically engineered models have revealed protective or harmful roles for various components of the innate immune system in response to acute injury and repair mechanisms for the intestinal mucosa. Advances in the use of endoscopic and radiologic techniques have allowed identification of inflammatory biomarkers and in-vivo monitoring of cell trafficking towards inflammatory sites. Translational research has shed light on pathogenic mechanisms through which recent biological treatments may exert their beneficial effects in patients with IBD. Finally, novel therapies are continuously tested in animal models of IBD as part of preclinical drug development programs.Animal models of intestinal inflammation continue to be important research tools with high significance for understanding the pathogenesis of IBD and exploring novel therapeutic options. Development of additional experimental models that address existing limitations, and more closely resemble the characteristics of Crohn's disease and ulcerative colitis are greatly needed.

Amongst the available therapies for moderate to severe Crohn's disease (CD) patients who are refractory to conventional therapy, anti-TNF blockers are the most effective biological treatment option. However, many patients experience a primary or secondary non-response to anti-TNF therapy, creating the need for alternative biological drugs that target different mechanisms of action and inflammatory pathways. Natalizumab, the first non-anti-TNF biological drug to be approved for treatment of CD patients, is a recombinant humanized antibody that targets the α

Inflammatory bowel disease causes chronic, relapsing intestinal inflammation that can lead to the development of colorectal cancer. Members of the TNF superfamily are key regulators of intestinal inflammation. In particular, TNF-like weak inducer of apoptosis (TWEAK) and its receptor, Fn14, are involved in normal and pathologic intestinal tissue remodeling. In this study, we show that the TWEAK/Fn14 signaling complex plays a protective role during the acute stage of intestinal inflammation and contributes to the prevention of colitis-associated cancer during chronic inflammation through its proapoptotic effects. Colitis was induced in Fn14−/− and Fn14+/+ wild-type littermates by administering 3% dextran sodium sulfate (DSS) for 7 days followed by 2-week recovery; azoxymethane (AOM) administration followed by two cycles of DSS/recovery was used to induce tumors. Reciprocal bone marrow chimeric mice were generated to compare hematopoietic and nonhematopoietic-specific effector tissues. Fn14−/− mice had enhanced susceptibility to colitis compared with Fn14+/+ controls as assessed by endoscopic and histologic inflammatory scores, daily weight loss, and mortality rates during recovery after DSS administration. Bone marrow transfer experiments showed that both hematopoietic and nonhematopoietic components are involved in protection against colitis. Tumor lesions were found in the colons of most Fn14−/− mice, but not Fn14+/+ controls. AOM/DSS administration enhanced susceptibility to tumorigenesis in Fn14−/− mice. Overall, these findings show that Fn14 plays a protective role during the acute stages of intestinal inflammation, and its absence promotes the development of colitis-associated cancer. Cancer Res; 76(22); 6533–42. ©2016 AACR.

Inflammatory bowel disease (IBD) is a chronic immune-mediated inflammatory disease of the intestine that includes both Crohn's disease and ulcerative colitis, and afflicts nearly 1 million people throughout North America. As our understanding of IBD pathogenesis grows, several new therapies have been developed that use monoclonal antibodies to specifically target key mediators and biological pathways implicated in IBD immune dysfunction. One important pathway involves leukocyte trafficking and infiltration into the affected intestinal tissues. This review provides a summary of the different therapies that have been developed to inhibit leukocyte trafficking to the inflamed gut, and evaluates the relative safety and efficacy of these novel drugs within the context of existing medical therapies for IBD.

Inflammatory bowel diseases (IBD), including Crohn’s disease (CD) and ulcerative colitis (UC), are chronic, relapsing inflammatory condition of the gastrointestinal tract. CD and UC have distinct pathologic and clinical characteristics and despite the extensive amount of research conducted over the past decades, their pathogenesis remains still poorly understood. So far, the accepted dogma is that IBD results from dysregulated mucosal immune response to environmental factors in genetical susceptible hosts. Various components are implicated in the pathogenesis of IBD, including genetic susceptibility, environmental and microbial factors, intestinal epithelial cells and components of innate and adaptive immune system. Given the complexity of IBD, several different animal models of IBD have been developed during the last years. Animal models are very important tools to study the involvement of various factors in the pathogenesis of IBD and, importantly, to test new therapeutic options. This review examines some of the key components that have been found to be closely associated to IBD and describe the distinct features of some of the most important IBD models.

Increasing evidence suggests that a deficit in innate immunity may play a causative role in the pathogenesis of inflammatory bowel disease. The most compelling support for this hypothesis comes from the genetic association of Crohn disease (CD) with carriage of polymorphisms within the NOD2 gene, which represent the most frequent genetic defect in CD. Our findings suggest that SAMP1/YitFc mice, which develop CD-like ileitis in the absence of NOD2 genetic mutations, fail to respond to MDP administration by displaying decreased innate cytokine production and impaired bacterial clearance before the onset of disease. This provides evidence that dysregulated NOD2 signaling, genetic or functional in nature, predisposes to chronic intestinal inflammation, and supports a new paradigm that CD may occur from a deficit in innate immunity as opposed to an overly aggressive immune response. This new paradigm could lead to potential development of new preventative or therapeutic modalities for patients with CD.

CCR9 antagonism is a promising new therapeutic approach for the treatment of Crohn's disease. CCR9 is expressed on the cell surface of memory/effector CD4(+) T cells and selectively binds to the small intestinal lymphocyte chemoattractant CCL25 (TECK). Blockade of the CCR9/CCL25 interaction inhibits lymphocyte homing to the intestinal mucosa, thereby limiting inflammation and disease at this site.This review details the current research on CCR9 antagonism and summarizes available clinical trial data for vercirnon , a selective CCR9 antagonist currently under development.If the results of ongoing large-scale clinical trials of vercirnon are in line with preliminary reports, CCR9 antagonism may have comparable efficacy to anti-TNF therapies and a potentially superior safety profile, making it the latest addition to the growing arsenal of immunomodulatory drug therapies available to combat Crohn's disease. Moreover, since vercirnon is an oral drug, its associated costs will likely be much lower than expensive infusion-based anti-TNF therapies, providing further economic benefits.

Although regulatory T cells (Tregs) have been implicated in inflammatory bowel disease, Tregs from Crohn's disease (CD) patients are increased in number and function normally in vitro. To clarify this disparity, we studied Treg function in vivo using a spontaneous model of CD-like ileitis. We first administered anti-CD25-depleting antibodies to SAMP1/YitFc (SAMP) mice to assess ileitis; mesenteric lymph node cells were then transferred into SCID (severe combined immunodeficient) recipients to induce colitis. CD25 depletion increased the severity of both spontaneous ileitis and adoptively transferred colitis. Interestingly, a second transfer of CD4(+)CD25(+) cells from untreated AKR control mice was able to ameliorate the induced colitis, whereas CD4(+)CD25(+) cells from untreated SAMP mice were not, suggesting a functional abnormality in SAMP Tregs. Anti-CD25 treatment in SAMP mice also induced proliferation of CD25(-)Foxp3(+) Tregs, which had a proinflammatory intestinal T helper type 1/ T helper type 2 (Th1/Th2) effector phenotype. These studies demonstrate Treg dysfunction in a spontaneous model of CD-like ileitis.

Crohnâs disease and ulcerative colitis, together known as inflammatory bowel disease, are debilitating chronic disorders of unknown cause and cure. Our evolving understanding of these pathologies is enhanced greatly by the use of animal models of intestinal inflammation that allow in vivo mechanistic studies, preclinical evaluation of new therapies, and investigation into the causative factors that underlie disease pathogenesis. Several animal models, most commonly generated in mice, exist for the study of colitis. The appropriateness of their use often can be determined by their mode of generation (ie, chemical induction, T-cell transfer, targeted genetic manipulation, spontaneously occurring, and so forth), the type of investigation (mechanistic studies, pathogenic experiments, preclinical evaluations, and so forth), and the type of inflammation that occurs in the model (acute vs chronic colitis, tissue injury/repair, and so forth). Although most murine models of inflammatory bowel disease develop inflammation in the colon, Crohnâs disease most commonly occurs in the terminal ileum, where a very limited number of mouse models manifest disease. This review discusses appropriate experimental applications for different mouse models of colitis, and highlights the particular utility of 2 highly relevant models of Crohnâs-like ileitisâthe spontaneous SAMP1/YitFc inbred mouse strain and the genetically engineered TnfÎAU-rich element/+ mouse model of tumor necrosis factor overexpression, both of which bear strong resemblance to the human condition. Similar to patients with Crohnâs disease, SAMP1/YitFc ileitis develops spontaneously, without chemical, genetic, or immunologic manipulation, making this model particularly relevant for studies aimed at identifying the primary defect underlying the occurrence of Crohnâs ileitis, as well as preclinical testing of novel treatment modalities. Keywords: Crohnâs Disease, Ulcerative Colitis, SAMP1/YitFc, TnfÎARE/+

Although genetic polymorphisms in NOD2 (nucleotide-binding oligomerization domain-containing 2) have been associated with the pathogenesis of Crohn's disease (CD), little is known regarding the role of wild-type (WT) NOD2 in the gut. To date, most murine studies addressing the role of WT Nod2 have been conducted using healthy (ileitis/colitis-free) mouse strains. Here, we evaluated the effects of Nod2 deletion in a murine model of spontaneous ileitis, i.e., the SAMP1Yit/Fc (SAMP) strain, which closely resembles CD. Remarkably, Nod2 deletion improved both chronic cobblestone ileitis (by 50% assessed, as the % of abnormal mucosa at 24 wks of age), as well as acute dextran sodium sulfate (DSS) colitis. Mechanistically, Th2 cytokine production and Th2-transcription factor activation (i.e., STAT6 phosphorylation) were reduced. Microbiologically, the effects of Nod2 deletion appeared independent of fecal microbiota composition and function, assessed by 16S rRNA and metatranscriptomics. Our findings indicate that pharmacological blockade of NOD2 signaling in humans could improve health in Th2-driven chronic intestinal inflammation.

TNF-like cytokine 1A (TL1A) is expressed on APCs and provides costimulatory signals to activated lymphocytes that bear its functional receptor, death receptor 3 (DR3). TL1A/DR3 signaling is involved in the pathogenesis of human and experimental inflammatory bowel disease. In the current study, we investigated the role of this cytokine/receptor pair in acute intestinal injury/repair pathways. We demonstrate that intact DR3 signaling protected mice from acute dextran sodium sulfate colitis because DR3−/− mice showed more severe mucosal inflammation and increased mortality. DR3−/− mice were compromised in their ability to maintain adequate numbers of CD4+CD25+Foxp3+ regulatory T cells in response to acute mucosal damage. This defect in immune regulation led to a nonspecific upregulation of effector proinflammatory pathways, which was most prominent for the Th17 immunophenotype. TL1A−/− mice were similarly more susceptible to dextran sodium sulfate colitis, although without mortality and with delayed kinetics compared with DR3−/− mice, and also displayed significantly reduced numbers of regulatory T cells. Infection of DR3−/− mice with Salmonella typhimurium was associated with defective microbial clearance and elevated bacterial load. Taken together, our findings indicate a novel protective role for the TL1A/DR3 axis in the regulation of mucosal homeostasis during acute intestinal injury/repair, which contrasts with its known pathogenic function during chronic intestinal inflammation.

Although the adaptive immune system traditionally has been the primary focus of investigations into the pathogenesis of inflammatory bowel disease (IBD), it is now clear that innate immune responses play an equally important, or perhaps even primary, role in disease initiation. Intestinal barrier function defects and genetic associations with the nucleotide-binding oligomerization domain and Toll-like receptor pathways suggest that the innate immune system has failed to protect the host against the vast array of commensal bacteria in the gut. This hypothesis is supported further by the observation that probiotic agents exert anti-inflammatory effects in the intestine through stimulation, rather than suppression, of the mucosal innate immune system. Moreover, it is now clear that adaptive immune responses involved in IBD pathogenesis are more complex than the traditionally dichotomous Th1/Th2 paradigm. Finally, mounting evidence suggests that the Th17 effector pathway may contribute to Crohn's disease pathogenesis.

The pathogenesis of Crohn’s disease has been associated with a dysregulated response of the mucosal immune system against intraluminal Ags of bacterial origin. In this study, we have investigated the effects of germfree (GF) conditions in the SAMP1/YitFc murine model of Crohn’s disease-like ileitis. We show that the bacterial flora is not essential for ileitis induction, because GF SAMP1/YitFc mice develop chronic ileitis. However, compared with disease in specific pathogen-free (SPF) mice, ileitis in GF mice is significantly attenuated, and is associated with delayed lymphocytic infiltration and defective mucosal expression of Th2 cytokines. In addition, we demonstrate that stimulation with purified fecal Ags from SPF, but not GF mice leads to the generation of IL-4-secreting effector lymphocytes. This result suggests that commensal bacteria drive Th2 responses characteristic of the chronic phase of SAMP1/YitFc ileitis. Finally, adoptive transfer of CD4-positive cells from GF, but not SPF mice induces severe colitis in SCID recipients. These effects were associated with a decreased frequency of CD4+CD25+Foxp3+ T cells in the mesenteric lymph nodes of GF mice compared with SPF mice, as well as lower relative gene expression of Foxp3 in CD4+CD25+ T cells in GF mice. It is therefore apparent that, in the absence of live intraluminal bacteria, the regulatory component of the mucosal immune system is compromised. All together, our results indicate that in SAMP1/YitFc mice, bacterial flora exacerbates intestinal inflammation, but is not essential for the generation of the chronic ileitis that is characteristic of these mice.

Crohn's Disease (CD) is a chronic inflammatory bowel disease (IBD) that can affect any portion of the gastrointestinal tract and can cause significant morbidity. A variety of animal models of both acute and chronic intestinal inflammation have been developed to investigate disease pathogenesis and novel treatment modalities. These include chemically induced, genetically manipulated and immune-mediated models of gut inflammation, each of which possesses similarities to human IBD and offers unique advantages for studying specific aspects of disease pathogenesis. However, the majority of these models are characterized by colitis and, unlike human CD, do not involve the small intestine. More recently, murine models of chronic ileal inflammation have been characterized that spontaneously develop and closely resemble human CD with regard to disease location, histologic features and clinical response to therapy. Two mouse models of experimental ileitis will be discussed in this review: the TNF DeltaARE and SAMP1/YitFc strains. Studies using these new models might provide important insight into the pathogenesis of human CD and test the efficacy of potential therapies to treat this devastating disease.

Background & Aims: Academic medical centers are under pressure to contain resources. The University of Virginia Digestive Health Service Center (DHSC) is a fully integrated inpatient service combining gastroenterology, hepatology, surgery, pathology, radiology, and nutritional services. The aim of this study was to evaluate whether integration of digestive health services can contain resource use among gastrointestinal (GI) inpatient admissions. Methods: This is a cohort study of 2934 inpatient cases admitted to a referral academic medical center between January 1, 1998, and June 30, 2000, with a primary diagnosis of an esophageal disorder, appendicitis, abdominal hernia, intestinal obstruction, diverticulitis, biliary tract disease, liver disease, a pancreatic disorder, or GI hemorrhage. Cases were grouped by admitting service (DHSC vs. other nonintegrated inpatient services). Total cost, length of stay, and 30-day readmission rate were adjusted for differences in baseline patient characteristics and compared. Results: DHSC admission was associated with significant cost savings ( P = 0.0363) and reduced length of stay ( P P = 0.0077), GI hemorrhage ( P = 0.0031), and diverticulitis ( P = 0.0497); reductions in length of stay were seen for patients with liver disease ( P = 0.0314), GI hemorrhage ( P = 0.0212), diverticulitis ( P = 0.0017), esophageal disorders ( P = 0.0006), and abdominal hernia ( P = 0.0458). DHSC patients with pancreatic disorders had increased total cost ( P = 0.0247), but no difference in length of stay ( P = 0.7504) and a lower 30-day readmission rate ( P = 0.0478). Conclusions: Integration of digestive health services reduces resource use for patients with digestive diseases and may improve outcomes for patients with pancreatic disorders. A multidisciplinary service center may represent a more efficient model for health care delivery for these patients.

Over the past decade, the introduction of a new class of anti-TNFα drugs has dramatically changed the approach taken to the management of Crohn's disease (CD). An increasing number of patients are receiving treatment with these advanced biological therapies, and the risk of adverse events that may be associated with their use must be carefully evaluated.Safety data about the three anti-TNFα drugs currently approved for use in CD patients (infliximab, adalimumab, and certolizumab pegol) is critically evaluated, including data coming from randomized clinical trials and post-marketing reports. Possible side effects of anti-TNFα agents are presented as drug-, class- and disease-specific adverse events. Management strategies to minimize the occurrence of side effects are summarized.The safety profile of the three anti-TNFα drugs approved for clinical use in CD patients appears to be comparable among drugs. Data from clinical trials and a growing body of information from post-marketing surveillance indicate that anti-TNFα agents are generally safe, and that most of the observed side effects are mild and easily manageable. Nonetheless, serious short- and long-term adverse events may occur. Accurate selection of patients, careful pre-treatment evaluation, and regular follow-up during therapy could potentially reduce the rate of adverse events related to the use of anti-TNFα drugs.

Cytokines are integral mediators for maintaining intestinal mucosal homeostasis, as well as prominent effector molecules during chronic gut inflammatory diseases. This review focuses on recent studies of the role of specific cytokines in mucosal immunity.Dichotomous, or even opposing, functions have been described for several cytokines involved in intestinal innate immunity (most notably for members of the interleukin-1 family), which depend on the specific inflammatory conditions within the intestinal mucosa. For example, both interleukin-1α and interleukin-33 exhibit 'alarmin'-type properties that can signal tissue or cell damage, which further add to their well described proinflammatory roles. Costimulatory molecules of the tumor necrosis factor/tumor necrosis factor receptor superfamily, such as TNF-like cytokine 1A and LIGHT, are actively involved in mucosal proinflammatory pathways, but also may exert protection against infectious agents to facilitate recovery from acute inflammation. Finally, innate lymphoid cells are increasingly recognized as important cellular sources of pivotal mucosal cytokines, including the interleukin-23/T helper 17 cytokine, interleukin-22.Elucidating the complexity of cytokine signaling within the normal mucosa and during acute and chronic inflammation will be a pivotal step toward understanding the pathogenesis of immune-mediated gut diseases and developing effective therapies to treat them.

We reported previously that human colonic epithelial cells produce the C-X-C chemokine epithelial neutrophil-activating peptide-78 (ENA-78) and that its expression is up-regulated in ulcerative colitis. The aim of this study was to investigate the transcriptional regulation of ENA-78 gene expression in Caco-2 intestinal epithelial cells. Reporter gene transfection and electrophoretic mobility shift assay studies demonstrated that cooperation between two regions of the ENA-78 promoter were required for maximal gene expression in interleukin-1beta-stimulated Caco-2 cells. Binding of activated p50/p65 nuclear factor-kappaB to nucleotides -82 to -91 was essential for interleukin-1beta-dependent gene transcription, whereas binding of constitutively expressed zinc-requiring nuclear factors to nucleotides -125 to -134 (site A) was required for basal gene expression. Scanning mutagenesis of site A demonstrated overlapping binding elements at this locus. One site (CTCCCCC) bound Sp1 and Sp3, and overexpression of Sp1 (but not Sp3) up-regulated basal ENA-78 transcription. Another site (CCCCTCCCCC) was found to bind the zinc finger nuclear factor ZBP-89, and overexpression of this protein significantly repressed ENA-78 reporter gene activity. This study demonstrates that ENA-78 gene expression in Caco-2 intestinal epithelial cells is subject to complex regulation involving the coordinate binding of ZBP-89, Sp1, and nuclear factor-kappaB to the ENA-78 promoter.

Background & Aims: The cost-utility of infliximab is unknown. The aim of this study was to determine the incremental cost-utility (CU inc ) of medical therapy for Crohn's disease (CD) perianal fistula. Methods: A Markov model was used to simulate a 1-year treatment period with the following: 6-mercaptopurine and metronidazole [6MP/met] (comparator), 3 infliximab infusions + 6MP/met as second-line therapy (intervention I), infliximab with episodic reinfusion (intervention II), and 6MP/met + infliximab as second-line therapy (intervention III). Utilities were elicited from patients with CD and healthy individuals by standard gamble, and costs were obtained from hospital billing data. Uncertainty was assessed by sensitivity analysis. Results: All strategies had similar effectiveness. Interventions I, II, and III were slightly more effective, but also more costly than 6MP/met (Intervention I: CU inc = $355,450/quality-adjusted life-years [QALY]; Intervention II: CU inc = $360,900/QALY; Intervention III: CU inc = $377,000/QALY). If the cost of infliximab were reduced to $304 per infusion, the CU inc for intervention II would be $54,050/QALY. Conclusions: Based on available data, all strategies had similar effectiveness in our model, but infliximab was much more expensive than 6MP/met. The incremental benefit of infliximab for treating CD perianal fistulae over a 1-year period may not justify the higher cost. Prospective studies directly comparing 6MP/met and infliximab are warranted. GASTROENTEROLOGY 2001;120:1640-1656

An association may exist between Crohn's disease (CD) and lymphoid/myeloid malignancies. We aimed to evaluate the 2-year cumulative incidence rate of lymphoid/myeloid malignancy among hospitalized CD patients. This is a retrospective cohort study using hospital discharge data from California and Virginia. Cohorts were defined by the presence or absence of a CD diagnosis in all patients discharged during a single calendar year (Year-2). The presence or absence of lymphoid/myeloid malignancy was determined for all hospitalizations during a 4-year period (Year-1 to Year-4) for each member of both cohorts. To obtain a 2-year cumulative incidence rate, patients with lymphoid/myeloid malignancy prior to or at the time of their first admission in Year-2 were excluded. Patients were followed for 8 quarters after this admission for the incidence of lymphoid/myeloid malignancy. Cumulative incidence rates and odds ratios were calculated. The crude 2-year incidence rate of lymphoid/myeloid malignancy among hospitalized CD patients was 3.87/1,000 CD patients (21/5,426; 95% CI = 2.40–5.92). The odds ratio adjusted for age, gender, and race was 2.04 (95% CI = 1.33–3.14, p < 0.001). The 2-year cumulative incidence of lymphoid/myeloid malignancies among hospitalized CD patients is greater than that seen in hospitalized patients without CD. This finding supports the need for further prospective population-based studies.

Interleukin (IL)-16 is a T lymphocyte- derived cytokine that uses CD4 as its receptor and hence selectively recruits CD4-bearing cells. Infiltrating CD4(+) T cells are a feature of Crohn's disease; however, the role of IL-16 in intestinal inflammation is unknown. The aim of this study was to determine whether IL-16 production is increased in inflammatory bowel disease and whether IL-16 participates in trinitrobenzene sulfonic acid (TNBS)-induced colitis in mice.IL-16 messenger RNA and protein levels in inflammatory bowel disease tissues were determined by reverse-transcription polymerase chain reaction and enzyme-linked immunosorbent assay. C57BL/6 or BALB/c mice were treated with vehicle, TNBS alone, TNBS + anti-IL-16 monoclonal antibody (mAb), TNBS + control mAb, or were untreated. Colonic injury and inflammation were evaluated after 3 or 10 days.Colonic IL-16 protein levels were increased in patients with Crohn's disease (P0.05) but not ulcerative colitis. Anti-IL-16 mAb treatment significantly reduced TNBS-induced weight loss (P0.001), mucosal ulceration (P0.05), myeloperoxidase activity (P0.001), and TNBS-mediated increases in mucosal levels of IL-1beta (P0.05) and tumor necrosis factor alpha (P0.01).Anti-IL-16 mAb reduced colonic injury and inflammation induced by TNBS in mice. Colonic mucosal IL-16 levels were elevated in Crohn's disease, suggesting a role for IL-16 in the pathophysiology of inflammatory bowel disease.

The precise cause of inflammatory bowel disease remains unclear. Relevant animal models are important tools for studying the underlying mechanisms of inflammation and disease pathogenesis. The purpose of this review is to summarize the various types of animal models available for use in inflammatory bowel disease research and to illustrate how these models have contributed to a better understanding of the etiopathogenesis of inflammatory bowel disease, particularly focusing on papers published during calendar year 1999. Studies using appropriate animal models have provided important discoveries in this field of investigation. These include determination of the key role that pathogenic and regulatory T cells, proinflammatory and immunoregulatory cytokines, indigenous bacterial flora, and putative predisposing genes play in the disease process. The availability of new animal models that closely resemble the human disease is expected to allow further characterization of the initiating event(s) in inflammatory bowel disease and lead to a possible cure for this devastating disease.

Crohn's Disease (CD) affects more than 500,000 individuals in the United States and represents the second most common chronic inflammatory disorder after rheumatoid arthritis. Although major advances have been made in defining the basic mechanisms underlying chronic intestinal inflammation, the precise etiopathogenesis of CD remains unknown. We have recently characterized two novel mouse models of enteritis that express a CD-like phenotype, namely the TNF ΔARE model of tumor necrosis factor (TNF) overexpression and the SAMP1/Yit model of spontaneous ileitis. The unique feature of these models is that they closely resemble CD for location and histopathology. These genetically manipulated new models of intestinal inflammation offer a powerful tool to investigate potential causes of human disease and may allow the development of novel disease-modifying therapeutic modalities for the treatment of CD.

The relationship between chronic inflammatory conditions and malignancy is complex. We describe the clinical course of 2 patients with Crohn's disease (CD) in whom lymphoma was diagnosed after treatment with infliximab. The first patient was a 61-year-old man with a 30-year history of fistulizing CD in whom B-cell non-Hodgkin's lymphoma was diagnosed 9 months after treatment with infliximab. The second is a 29-year-old man with CD in whom nodular sclerosing Hodgkin's lymphoma was diagnosed 3 weeks after infusion with infliximab. The lymphoma presented with pleural effusions, mediastinal and cervical adenopathy, and no gastrointestinal lesion. We describe the implications of these cases for the use of immunomodulatory therapy in CD and the questionable association between CD and lymphoma.

BACKGROUND AND AIM Human and animal studies have clearly established tumor necrosis factor (TNF)α as an important mediator of Crohn's disease pathogenesis. However, whether systemic or only local TNFα overproduction is required for the development of chronic intestinal inflammation and Crohn's disease remains unclear. The aim of this study was to assess the contribution of intestinal epithelial-derived TNFα to the development of murine Crohn's-like ileitis. METHODS We adapted the well-established TNF(∆ARE/+) mouse model of Crohn's disease (which systemically overexpresses TNFα) to generate a homozygous mutant strain that overexpress TNFα only within the intestinal epithelium. Intestinal-specific TNF(i∆ARE/i∆ARE) mice were examined for histopathological signs of gut inflammation and extraintestinal manifestations of Crohn's disease. The mucosal immune phenotype was characterized, and the contribution of specific lymphocyte populations to the pathogenesis of TNF(i∆ARE/i∆ARE) ileitis was assessed. RESULTS TNF(i∆ARE/i∆ARE) mice had increased mucosal and systemic TNFα levels compared to wild-type controls (P

Background: We previously showed that the probiotic mixture, VSL#3, prevents the onset of ileitis in SAMP/YitFc (SAMP) mice, and this effect was associated with stimulation of epithelial-derived TNF. The aim of this study was to determine the mechanism(s) of VSL#3-mediated protection on epithelial barrier function and to further investigate the "paradoxical" effects of TNF in preventing SAMP ileitis. Methods: Permeability was evaluated in SAMP mice prior to the onset of inflammation and during established disease by measuring transepithelial electrical resistance (TEER) on ex vivo-cultured ilea following exposure to VSL#3 conditioned media (CM), TNF or VSL#3-CM + anti-TNF. Tight junction (TJ) proteins were assessed by qRT-PCR, Western blot, and confocal microscopy, and TNFRI/TNFRII expression measured in freshly isolated intestinal epithelial cells (IEC) from SAMP and control AKR mice. Results: Culture with either VSL#3-CM or TNF resulted in decreased ileal paracellular permeability in pre-inflamed SAMP, but not SAMP with established disease, while addition of anti-TNF abrogated these effects. Modulation of the TJ proteins, claudin-2 and occludin, occurred with a significant decrease in claudin-2 and increase in occludin following stimulation with VSL#3-CM or TNF. TNF protein levels increased in supernatants of SAMP ilea incubated with VSL#3-CM compared to vehicle, while IEC-derived TNFR mRNA expression decreased in young, and was elevated in inflamed, SAMP versus AKR mice. Conclusions: Our data demonstrate that the previously established efficacy of VSL#3 in preventing SAMP ileitis is due to direct innate and homeostatic effects of TNF on the gut epithelium, modulation of the TJ proteins, claudin-2 and occludin, and overall improvement of intestinal permeability. © 2012 Corridoni et al.

The SAMP1/YitFc mouse strain represents a model of Crohn's disease (CD)-like ileitis that is ideal for investigating the pathogenesis of chronic intestinal inflammation. Different from the vast majority of animal models of colitis, the ileal-specific phenotype characteristic of SAMP1/YitFc mice occurs spontaneously, without genetic, chemical, or immunological manipulation. In addition, SAMP1/YitFc mice possess remarkable similarities to the human condition with regard to disease location, histologic features, incidence of extraintestinal manifestations, and response to conventional therapies. SAMP1/YitFc mice also display a well-defined time course of a predisease state and phases of acute and chronic ileitis. As such, the SAMP1/YitFc model is particularly suitable for elucidating pathways that precede the clinical phenotype that may lead to preventive, and therefore more efficacious, intervention with the natural course of disease, or alternatively, for the development of therapeutic strategies directed against chronic, established ileitis. In this review we summarize important contributions made by our group and others that uncover potential mechanisms in the pathogenesis of CD using this unique murine model of chronic intestinal inflammation. Copyright © 2011 Crohn's & Colitis Foundation of America, Inc.

Probiotic formulations are widely available and have a variety of proposed beneficial effects, including promotion of gut health. The mechanisms of action of probiotic bacteria in the intestine are still unclear but are generally attributed to an antiinflammatory effect. Here, we demonstrate that the multiple probiotic formulation VSL#3 prevents the onset of intestinal inflammation by local stimulation of epithelial innate immune responses (i.e., increased production of epithelial-derived TNF-α and restoration of epithelial barrier function in vivo). We also demonstrate that probiotic bacteria stimulate epithelial production of TNF-α and activate NF-κB in vitro. Our results support the hypothesis that probiotics promote gut health through stimulation, rather than suppression, of the innate immune system. Furthermore, our findings provide the perspective that defects in innate immunity may play a critical role in the pathogenesis and progression of intestinal disorders, such as inflammatory bowel disease.

Inflammatory bowel disease (IBD) is a chronic relapsing and remitting digestive disorder that includes both Crohn’s disease and ulcerative colitis. The underlying cause of IBD remains unclear but is thought to involve an inherent defect in the innate immune system, possibly a breach in epithelial barrier function, which disrupts the delicate homeostatic balance achieved between commensal bacteria residing in the gut and immunosurveillance mechanisms of the mucosal immune system. The result is an overly aggressive adaptive immune response against the commensal flora or other antigens that involves massive recruitment of leukocytes into the affected intestinal tissues, inflammation, and tissue damage. Given that the exact pathological mechanisms underlying IBD are unknown, therapeutic strategies have been developed to treat the apparent symptoms of disease rather than the underlying cause of disease. Patients with ulcerative colitis have traditionally been treated with generalized anti-inflammatory medications such as 5-aminosalicylates and corticosteroids with significant success. However, a substantial number of patients either lose their response to corticosteroids (steroid refractory) or are unable to taper off corticosteroids without disease recurrence (steroid dependent). In addition, extended use of corticosteroids is associated with significant side effects. In recent years, biological agents have been developed that more specifically target the proposed underlying pathogenic mechanisms of disease. The most successful example has been infliximab, which is a monoclonal antibody infusion therapy that targets the proinflammatory cytokine TNFα. In randomized clinical trials, 69% of steroid refractory ulcerative colitis patients experienced a clinical response to infliximab 1. However, the long-term effects of blocking TNFα are unknown, and several serious side effects have been reported with the use of biological therapy, including serious infections and possible lymphoma 2. As a result of these therapeutic limitations, many patients with steroid-dependent or steroid refractory ulcerative colitis end up undergoing a total colectomy. Clearly, more effective medical therapies with fewer side effects would greatly enhance the health-related quality of life for these patients. Currently, two selective adsorption apheresis devices are approved for use in Japan and Europe, including Cellsorba leukocytaphoresis column and the Adacolumn adsorptive extracorporal granulcyte-monocyte apheresis device. In this issue of the Journal, Hibi et al. present the results of a large post-marketing study of the Adacolumn (Japan Immunoresearch Laboratoroes Co., Ltd), a leukocytapheresis column that selectively adsorbs granulocytes and monocytes extracorporally from the peripheral blood of patients with ulcerative colitis. The aim of the study was to further assess the safety and efficacy of granulocyte and monocytes apheresis (GMA) using the Adacolumn in a large cohort of patients with active ulcerative colitis. The study followed 697 patients who received a total of 5,287 GMA sessions at 53 centers in Japan over a period of seven years. Patients were assessed before receiving GMA and two weeks post GMA; no long term follow-up was performed. At the time of enrollment, 92% of patients were being treated with aminosalicylates, 74% of patients were on corticosteroids, and 9% of patients were receiving other immunomodulatory medications. No serious adverse events were reported in association with the use of GMA, and mild or moderate adverse events were reported in 7.7% of the 697 patients studied, suggesting that the Adacolumn is indeed a safe intervention for patients with active ulcerative colitis. In accordance with the guidelines for post-marketing studies from the Japan Ministry of Health, 656 of the 697 patients enrolled were available for evaluation of efficacy. Of these 656 patients, 77.3% experienced a clinical response to GMA, and 71.1% experienced a clinical remission. Since a long-term follow-up was not performed, no data are available of the time to relapse in these patients. Moreover, although these data were collected from a relatively large study cohort, it is important to note that this is a post-marketing study that lacks randomization or a control group. Although 70% of the study cohort was classified as having refractory UC, no data is reported on the duration or dose of steroid use prior to receiving GMA, introducing the possibility that the effect of steroid use may have confounded the reported treatment effect for Adacolumn GMA. In addition, without an adequate control group it is impossible to know the true size of the “placebo effect” that is associated with extracorporal therapy. That is, some patients may have reported clinical improvements simply because they knew they were being treated, regardless of whether or not the therapy was effective for them. The fact that 69.4% of the subset of 219 patients who underwent endoscopic evaluation had endoscopic grading indices representative of clinical remission would support the notion that the placebo effect in this study was relatively small. However, a randomized, double-blind, sham-controlled study of Adacolumn GMA in patients with moderate to severely active ulcerative colitis by Sands et al. found no difference in clinical remission or response rates between the GMA and sham treatment groups 3. These results suggest the possibility that in an unblinded study extracorporal therapy alone may incur a placebo effect and thereby inflate the observed treatment effect, regardless of whether or not granulocytes and monocytes are actually adsorbed from the peripheral blood. Finally, patients were administered heparin, low molecular weight heparin, or nafamostat mesolate as an anti-coagulant during their extracorporal procedure. Although the GMA response rates among patients receiving the different anticoagulant was comparable, it should be noted that low molecular weight heparin itself has been evaluated as a potential therapy for patients with ulcerative colitis. However, a meta-analysis of low molecular weight heparin as well as multiple randomized controlled trials showed no benefit of heparin over placebo or as an adjunct to standard therapy 4–6. These potential confounding effects notwithstanding, Hibi et al. have shown that extracorporal treatment with the Adacolumn GMA is safe and associated with a very high rate of clinical remission and response in a large cohort of patients with ulcerative colitis. One important contribution of such a large-scale study is the ability to use the resulting data set to identify parameters that may be predictive of response to therapy. Hibi et al. performed univariate statistical analysis on the 656 patients for whom efficacy data were available and were able to identify hypersensitivity to food and/or drugs as predictive for a poor response to GMA. Multivariable logistical regression also identified baseline granulocyte count as predictive of response to GMA, when controlling for age and duration of disease. These data are useful for targeting Adacolumn GMA toward patients who are likely to benefit from the intervention. In summary, selective adsorption of granulocytes and monocytes from the peripheral blood of patients with active ulcerative colitis using the extracorporal Adacolumn GMA appears to be an extremely safe treatment modality. Although conflicting results have been reported regarding the efficacy of Adacolumn GMA, this study by Hibi et al. adds to the existing literature by providing data from the largest population of ulcerative colitis patients yet to be studied. If the observed treatment effect of 77.7% is representative of the true response rate, Adacolumn GMA would be a safe alternative to biological therapies for patients with refractory ulcerative colitis. In addition, granulocyte fractions could be used to help identify patients who are most likely to benefit from this procedure.

Cytokines and chemokines play an important role in inflammatory bowel disease (IBD) pathogenesis, as demonstrated by the efficacy of cytokine-targeted immunomodulatory therapy in treating IBD. The precise etiology of IBD is unknown, but disease pathogenesis clearly involves genetic, immunologic, and environmental factors. The current hypothesis for IBD etiology suggests that the disease is initiated and perpetuated by a dysregulated immune response to an unknown environmental antigen in a genetically susceptible host. A working hypothesis for the pathogenesis of Crohn's disease, the most debilitating form of IBD, is depicted in Fig. 1. In order to maintain gut homeostasis, the normal mucosal immune system must maintain a delicate balance between a network of proinflammatory and/ or inductive cytokines and anti-inflammatory and/or regulatory cytokines. During bacterial invasion the proinflammatory and inductive type I T-helper cell (Thl)-polarizing cytokines exert pleiotropic effects upon release from antigen-presenting cells (macrophages, dendritic ceUs, etc.) in the intestinal mucosa. Proinflammatory cytokines (i.e. interleukin [IL]-1, IL-6, and tumor necrosis factor [TNF]) activate immune cells in the lamina propria and stimulate intestinal epithelial cells (lEC) and macrophages to produce chemokines which, when secreted, estabUsh a chemotactic gradient across the intestinal mucosa, promoting leukocyte recruitment and extravasation across the intestinal endothelium. Meanwhile, Thlpolarizing cytokines (i.e. IL-12, IL-18, TNF) released from antigen-presenting cells (primarily macrophages) induce activation of naive intraepithelial and lamina propria T lymphocytes and Thl differentiation. These activated Thl cells release Thl cytokines (i.e. IL-2, interferon gamma [IFN-y], and lymphotoxin [LT]), which further perpetuate inflammatory and delayed hypersensitivity immune responses in the gut. In the normal gut mucosa this proinflammatory/ inductive immune response is kept in balance by a network of anti-inflammatory and regulatory cytokines. Regulatory cytokines (i.e. IL-10, IL-4, IL-5, IL-13, and transforming growth factor beta [TGFp]) are derived from many cellular sources within the intestine, including macrophages as well as type IIThelper (Th2) cells and type I T regulatory (Trl) cells. Along with anti-inflammatory cytokines (i.e. IL-1 receptor antagonist [IL-lra] and IL-11) derived primarily from lEC and macrophages, these Th2 cytokines serve to counterbalance the proinflammatory effects of Thl-mediated immune responses. For unknown reasons, patients with IBD cannot maintain normal gut homeostasis. An understanding of the cytokine network and its role in promoting IBD pathogenesis is a crucial step toward finding a cure for this devastating disease. This chapter provides an overview of the cytokines and chemokines that have been implicated in IBD, with specific focus on what is known about each cytokine in relation to IBD pathogenesis and treatment.

Background & Aims: Patients with steroid-refractory ulcerative colitis face a difficult treatment decision between colectomy and therapy with infliximab or cyclosporine. The aim of this study was to understand how individual patient preferences for the various treatment outcomes influence the optimal treatment decision for a given patient. Methods: A Markov model was used to simulate treatment with total colectomy with an ileo pouch–anal anastomosis (TC/IPAA), cyclosporine (CSA), infliximab (INFLX), and infliximab followed by cyclosporine for treatment failures (INFLX→CSA). Utility weights for treatment outcomes were elicited from 48 patients using both time trade-off and visual rating scale methods. Preference sets were applied to the model to identify the therapy that maximized quality-adjusted life years (QALYs) for each patient. Sensitivity analyses were performed to assess model robustness. Results: Optimal treatment was highly variable among patients (INFLX→CSA = 42%, 20/48; TC/IPAA = 37%, 18/48; CSA=21%, 10/48; INFLX=0%, 0/48). However, when average preference weights from our sample were applied to the model, medical treatments were superior to TC (CSA = .26 QALYs gained vs TC/IPAA; INFLX→CSA = .25 QALYs gained vs TC/IPAA). Conclusions: Patient preferences have a clear impact on the optimal treatment for steroid-refractory ulcerative colitis. Although averaged preferences support the use of medical interventions, a third of individual patients may benefit most from proceeding directly to colectomy. Failure to fully assess individual preferences may result in suboptimal treatment for these patients.

Background Choledocholithiasis during pregnancy in-creases the risk of morbidity and mortality for both fetus and mother because of cholangitis and pancreatitis. ERCP has been advocated as safe and effective in pre-gnant women, but fetal radiation exposure is not rou-tinely monitored. The aim of this study was to record fetal exposure to ionizing radiation during ERCP and to assess outcome. Methods Seventeen ERCPs were performed in preg-nant women between January 1995 and August 2003. Techniques to minimize fluoroscopy were used, and fluoroscopy times were recorded. Thermoluminescent dosimeters affixed to the skin of the mother were used to estimate fetal radiation exposure. Observations Mean gestational age was 18.6 (8.9) weeks (range 5–33 weeks). Mean fluoroscopy time was 14 (13) seconds (range 1–48 seconds). Estimated fetal radiation exposure was 40 (46) mrad (range 1–180 mrad). There was a correlation between fluoroscopy time and radiation exposure, but there was a wide range of radiation exposure for individual fluoroscopy times. Complications included post-sphincterotomy bleeding in one patient (controlled by hemoclip placement) and post-ERCP pancreatitis in one patient that necessitated 3 days of hospitalization. Two women developed third-trimester preeclampsia, and labor was induced in both. Thirteen of the 15 patients who delivered were contacted and they confirmed that their child was in good health. Conclusions ERCP with modified techniques is safe during pregnancy. Dosimetry should be routinely recorded. Gallstones occur in 8% of pregnant women 1 , 2 ; they tend to be uncomplicated, and therapy typically is deferred to the postpartum period. Choledocholithiasis may be associated with cholangitis and/or gallstone pancreatitis, both of which increase morbidity for the mother and/or the fetus. 3 ERCP has been advocated as a safe and effective alternative to surgery for management of choledocholithiasis complicating pregnancy. 4 , 5 Data on ERCP during pregnancy are derived from multiple small series and several case reports; these focus on endoscopic techniques, whereas data regarding radiation exposure are limited.

Megamitochondria with crystalline inclusions (MMC) have been previously described in nonalcoholic fatty liver; however, their distribution within hepatic zones is unknown. We sought to determine this distribution from the core liver biopsy specimens of 31 patients: 8 males and 23 females, age range 21 to 72 years. Twenty-nine showed evidence of nonalcoholic steatohepatitis (NASH) on biopsy with steatosis, inflammation, varying degree of fibrosis, ballooned hepatocytes, and Mallory hyaline, and two patients had cryptogenic cirrhosis thought to represent “burned out” NASH. Identified by transmission electron microscopy, the abundance of MMC was compared between low-stage (fibrosis stages 1 and 2) and high-stage (fibrosis stages 3 and 4) groups and between zones with or without difference in fibrosis stage. Regardless of stage, the MMC were distributed equally in all zones and were abundant similarly in low- and high-stage groups. This abundance did not correlate with the degree of oxidative stress (4-hydroxynonenal staining) or with the abundance of ballooned hepatocytes. Consistent with age as a risk factor for more severe disease, the median age for the low-stage group was significantly lower than that of the high-stage group (P = .003). In conclusion, in NASH, the MMC seem to be distributed randomly among zones and without variation in abundance, regardless of the fibrosis stage. The exact function of these structures remains to be defined. In this study, their presence did not seem to correlate with the light microscopic injury pattern represented by ballooned hepatocytes or degree of oxidative stress defined by immunostaining for 4-hydroxynonenal. (HEPATOLOGY 2004;39:1423–1429.)

Severe coagulopathy in fulminant hepatic failure (FHF) is difficult to correct by conventional means. Recombinant activated factor VII (rFVIIa) is an antihemophilic factor that has shown promise in treating coagulopathy in liver disease. Our aim is to review our experience with rFVIIa in treating the coagulopathy of FHF and compare these results with those of conventional therapy. Fifteen patients with FHF who met King's College criteria for orthotopic liver transplantation were studied. All were ascertained from our liver disease registry. Eight consecutive patients were administered fresh frozen plasma (FFP) alone, whereas seven consecutive patients were administered FFP and rFVIIa (40 microg/kg intravenous bolus). The two groups, with similar demographic characteristics, were compared in terms of measured parameters of coagulopathy (prothrombin time and international normalized ratio), amount of plasma infused, development of anasarca, ability to undergo intracranial pressure (ICP) transducer placement, bleeding complications, ability to undergo transplantation, and survival. All patients administered rFVIIa (after a single dose) versus none administered FFP alone had temporary (2- to 6-hour) correction of coagulopathy (P.0002). All patients administered rFVIIa versus 38% administered FFP alone were able to have an ICP transducer placed (P =.03). The rFVIIa group had less anasarca (P =.04). An equal number of patients underwent transplantation from each group, but overall survival was slightly better in the rFVIIa group (P =.04). Five of seven patients in the rFVIIa group were administered one or more subsequent doses of rFVIIa after placement of the ICP monitor (two patients, for additional procedures; three patients, prophylactically in the first 24 hours after ICP transducer placement) at the discretion of the attending physicians. We conclude that rFVIIa is effective in transiently correcting laboratory parameters of coagulopathy in patients with FHF. It facilitates the performance of invasive procedures and is associated with less frequent anasarca compared with conventional therapy. Our preliminary experience supports the need for further studies to define the optimal dosing, safety, and efficacy of rFVIIa in patients with FHF.

Regulation of messenger RNA stability by AU-rich elements is an important means of regulating genes induced by growth factors and cytokines. Nup475 (also known as tristetraprolin, or TIS11) is the prototype for a family of zinc-binding Cys(3)His motif proteins required for proper regulation of tumor necrosis factor mRNA stability in macrophages. We developed an Escherichia coli expression system to produce soluble Nup475 protein in quantity to study its RNA binding properties. Nup475 protein bound a tumor necrosis factor AU-rich element over a broad range of pH and salt concentrations by RNA gel shift. This binding was inhibited by excess zinc metal, providing a potential mechanism for previous reports of zinc stabilization of AU-rich element (ARE) containing messenger RNAs. Immobilized Nup475 protein was used to select its optimal binding site by RNA SELEX and revealed a strong preference for the extended sequence UUAUUUAUU, rather than a simple AUUUA motif. These findings were confirmed by site-directed mutagenesis of the tumor necrosis factor ARE and RNA gel shifts on c-fos, interferon-gamma, and interferon-beta ARE fragments. A weaker binding activity toward adenine-rich sites, such as a poly(A) tail RNA fragment, can partially disrupt the Nup475-tumor necrosis factor AU-rich element complex.

Low bone mineral density in inflammatory bowel disease—a study of the prevalence and risk factors

Purpose: Patients with inflammatory bowel disease (IBD) appear to be at increased risk for low bone mineral density (BMD). Most epidemiology studies to date are from centers with racially homogenous patient populations. The purpose of this study is to determine the prevalence and risk factors for low BMD in a large, racially heterogenous cohort of IBD patients living in the southeastern United States.