Novel therapies for inflammatory bowel disease

4-Methoxylonchocarpin attenuates inflammation by inhibiting lipopolysaccharide binding to Toll-like receptor of macrophages and M1 macrophage polarization

The roots of Abrus precatorius (AP, Fabaceae) have traditionally been used in Vietnam and China for the treatment of inflammatory diseases such as stomatitis, asthma, bronchitis, and hepatitis. Therefore, in this study, we isolated 4-methoxylonchocarpin (ML), an anti-inflammatory compound present in AP, and studied its anti-inflammatory effects in mice with 2,4,6-trinitrobenzenesulfonic acid (TNBS)-induced colitis. In lipopolysaccharide (LPS)-stimulated macrophages, ML was found to inhibit nuclear factor (NF)-κB activation and tumor necrosis factor (TNF) and interleukin (IL)-6 expression by inhibiting LPS binding to Toll-like receptor 4 (TLR4) in vitro. Oral administration of ML in mice with TNBS-induced colitis suppressed colon shortening and colonic myeloperoxidase activity. ML treatment significantly inhibited the activation of nuclear factor (NF)-κB and phosphorylation of transforming growth factor β-activated kinase 1 in the colon. Treatment with ML also inhibited TNBS-induced expression of IL-1β, IL-17A, and TNF. While ML reduced the TNBS-induced expression of M1 macrophage markers such as arginase-2 and TNF, it was found to increase the expression of M2 macrophage markers such as arginase-1 and IL-10. In conclusion, oral administration of ML attenuated colitis in mice by inhibiting the binding of LPS to TLR4 on immune cells and increasing the polarization of M1 macrophages to M2 macrophages.

Serpin B1 protects colonic epithelial cell via blockage of neutrophil elastase activity and its expression is enhanced in patients with ulcerative colitis

Serpin B1 is a monocyte neutrophil elastase (NE) inhibitor and is one of the most efficient inhibitors of NE. In the present study, we investigated the role of serpin B1 in the pathogenesis of ulcerative colitis by using clinical samples and an experimental model. The colonic expression of serpin B1 was determined by real-time polymerase chain reaction (PCR), Western blot analysis, and immunohistological studies in both normal and inflamed mucosa from patients with ulcerative colitis. Serpin B1 mRNA expression was determined by real-time PCR in the mouse dextran sodium sulfate (DSS)-induced colitis model. Young adult mouse colonic epithelial (YAMC) cells were used to determine the role of serpin B1. Serpin B1 gene transfected YAMC cells were treated with H(2)O(2) to measure cell viability. The expression of NE was determined in YAMC cells treated with H(2)O(2). NE-silenced YAMC cells were also treated with H(2)O(2) and then measured for viability. Upregulated expression of serpin B1 in colonic mucosa was confirmed from patients with active ulcerative colitis. Immunohistochemical studies showed that serpin B1 expression was localized not only in inflammatory infiltration cells but also in epithelial cells. Serpin B1 mRNA expression was also increased in colonic mucosa of mouse DSS-induced colitis. Serpin B1-transfected YAMC cells were resistant against the treatment of H(2)O(2). H(2)O(2) treatment significantly induced NE in YAMC cells, and NE-silenced YAMC cells were also resistant against the treatment of H(2)O(2). These results suggest that serpin B1 may be a novel marker of active ulcerative colitis and may play an important role in the pathogenesis of inflammatory bowel disease.

Serum concentration of interleukin 10, anti-mannan Candida antibodies and the fungal colonization of the gastrointestinal tract in patients with ulcerative colitis

PURPOSE

There is evidence for the immunomodulation disorders in the response to intestinal flora in inflammatory bowel disease, however, the role of yeasts in the aetiopathogenesis of ulcerative colitis has not been fully clarified. The aim of this study was to assess the serum concentration of interleukin 10 (IL-10), serum levels of anti-mannan Candida antibodies and fungal colonization of the lower part of the gastrointestinal tract in accordance with the clinical course of ulcerative colitis.

MATERIAL/METHODS

In 42 consecutive patients with ulcerative colitis serum concentration of IL-10 and anti-mannan Candida antibodies serum levels were measured with ELISA and the quantitative and qualitative fungal cultures of stool samples were performed.

RESULTS

In 20 patients IL-10 serum concentration was below the test sensitivity and in 11 patients it ranged between 0.78 and 9.43 (mean 3.38 +/- 2.8) pg/mL. Anti-mannan Candida antibodies were detected in 8 subjects (19.04%). Stool cultures revealed significant fungal colonization in 3 (8.33%) patients with the predominance of Candida albicans. In comparison with mild/moderate UC, IL-10 serum concentration was not higher in patients with severe course of the disease.

CONCLUSIONS

The results of our study show that IL-10 serum concentration correlates neither with the disease activity nor with the levels of anti-mannan Candida antibodies and the fungal colonization of the gastrointestinal tract in ulcerative colitis. It seems that IL-10 serum concentration cannot be a universal marker for the assessment of ulcerative colitis activity. Moreover, anti-mannan Candida antibodies and significant fungal colonization are present in the minority of patients with ulcerative colitis suggesting that yeasts have minor, if any, influence on the clinical course of the disease.

Improvement of real-time polymerase chain reaction for quantifying TNF-alpha mRNA expression in inflamed colorectal mucosa: an approach to optimize procedures for clinical use

OBJECTIVE

The precise measurement of local tumor necrosis factor alpha (TNF-alpha) expression in tissue is important in understanding the pathogenesis of inflammatory bowel diseases (IBD). Real-time polymerase chain reaction (PCR) is a sensitive, versatile method and is becoming a commonly used tool for the quantification of gene expression. The aim of this study was to optimize the laboratory procedure for biopsy sampling, storage and calibration of result for TNF-alpha mRNA quantification with real-time PCR of colorectal biopsies.

MATERIAL AND METHODS

Endoscopic biopsies from the colorectum were obtained from 18 patients with ulcerative colitis (UC), 11 patients with Crohn's disease (CD) and 18 normal controls. Optimization of procedures for real-time PCR performance was carried out.

RESULTS

The transport medium, RNAlater, exhibited a high preservation effect against RNA degradation even after 8 days of storage at room temperature; one biopsy from each patient was sufficient for RNA extraction, cDNA synthesis and TNF-mRNA quantification. An assay was established with a technical reproducible sensitivity of 100 copies/microL. The observed interassay variations were 7.4 % coefficient of variation (CV) and 7.2 % CV in low and high TNF-alpha mRNA expression biopsies, respectively. TNF-alpha mRNA levels in colorectal biopsies from patients with either CD or moderate to severe UC were markedly increased, and 8 approximately 9-fold higher than those in healthy controls.

CONCLUSIONS

This optimization improves the clinical use of real-time PCR for quantification of TNF-alpha gene expression in colorectal biopsies and provides a sensitive reproducible assay.

Antioxidant therapy with N-acetylcysteine plus mesalamine accelerates mucosal healing in a rodent model of colitis

The aims of this study were to examine the ability of the antioxidant N-acetylcysteine (NAC) and mesalamine (5-ASA) alone and in combination to affect TNBS-induced colitis in rat. Three days following induction of TNBS colitis rats were randomized to receive daily intracolonic treatment with NAC, 5-ASA, and NAC plus 5-ASA for 5 or 8 days. At the end of the treatment period macroscopic and microscopic colonic injuries were scored. Myeloperoxidase (MPO) activity and cytokine gene expression were measured in colonic tissues. Results indicated that treatment with NAC plus 5-ASA caused a significantly greater reduction in colonic injury than either agent alone. Furthermore, combination therapy inhibited significantly MPO activity and inflammatory cytokine gene expression in the distal colon of TNBS-treated animals. The beneficial effects of NAC plus 5-ASA on reduction of colonic injury and promotion of healing were most evident after 8 days of treatment.

Melatonin reduces inflammatory injury through inhibiting NF-kappaB activation in rats with colitis

Proinflammatory mediators are important in the pathogenesis of IBD, which are regulated by activation of NF-kappaB. The aim of this study was to investigate whether melatonin reduces inflammatory injury and inhibits proinflammatory molecule and NF-kappaB in rats with colitis. Rat colitis model was established by TNBS enema. NF-kappaB p65, TNF-alpha, ICAM-1, and IkappaBalpha in colon tissue were examined by immunohistochemistry, EMSA, RT-PCR, and Western blot analysis. Expression of proinflammatory molecule and activation of NF-kappaB were upregulated and IkappaB level decreased in rats with colitis. Melatonin reduces colonic inflammatory injury through downregulating proinflammatory molecule mediated by NF-kappaB inhibition and blockade of IkappaBalpha degradation.

Inflammatory bowel disease and endothelin-1: a review

Inflammatory bowel disease (IBD) appears to be an inappropriate response to an antigen that leads to chronic inflammation rather than repair. This review looks at the role of endothelin-1 (ET-1) as a proinflammatory agent in IBD. ET-1 antagonists in animal models reduce the incidence and severity of IBD. These antagonists may be useful for treatment of IBD in humans.

Novel drug delivery strategies for the treatment of inflammatory bowel disease

Inflammatory bowel disease (IBD) encompasses two idiopathic inflammatory diseases of the intestinal tract: Crohn's disease and ulcerative colitis. Existing therapy for IBD consists mainly of orally or rectally administered small drug molecules, such as 5-aminosalicylates and corticosteroids, or potent systemic immune suppressants. IBD presents a challenging target for drug delivery, particularly by the oral route, as, contrary to most therapeutic regimens, minimal systemic absorption and maximal intestinal wall drug levels are desired. Several delivery strategies are employed to achieve this goal, including the chemical modification of the drug molecules, the use of controlled- and delayed-release formulations and the use of bioadhesive particles. The goal of this review is to summarise existing IBD therapy and examine novel approaches in intestinal drug delivery.

Escherichia coli Nissle 1917 distinctively modulates T-cell cycling and expansion via toll-like receptor 2 signaling

Although the probiotic Escherichia coli strain Nissle 1917 has been proven to be efficacious for the treatment of inflammatory bowel diseases, the underlying mechanisms of action still remain elusive. The aim of the present study was to analyze the effects of E. coli Nissle 1917 on cell cycling and apoptosis of peripheral blood and lamina propria T cells (PBT and LPT, respectively). Anti-CD3-stimulated PBT and LPT were treated with E. coli Nissle 1917-conditioned medium (E. coli Nissle 1917-CM) or heat-inactivated E. coli Nissle 1917. Cyclin B1, DNA content, and caspase 3 expression were measured by flow cytometry to assess cell cycle kinetics and apoptosis. Protein levels of several cell cycle and apoptosis modulators were determined by immunoblotting, and cytokine profiles were determined by cytometric bead array. E. coli Nissle 1917-CM inhibits cell cycling and expansion of peripheral blood but not mucosal T cells. Bacterial lipoproteins mimicked the effect of E. coli Nissle 1917-CM; in contrast, heat-inactivated E. coli Nissle 1917, lipopolysaccharide, or CpG DNA did not alter PBT cell cycling. E. coli Nissle 1917-CM decreased cyclin D2, B1, and retinoblastoma protein expression, contributing to the reduction of T-cell proliferation. E. coli Nissle 1917 significantly inhibited the expression of interleukin-2 (IL-2), tumor necrosis factor alpha, and gamma interferon but increased IL-10 production in PBT. Using Toll-like receptor 2 (TLR-2) knockout mice, we further demonstrate that the inhibition of PBT proliferation by E. coli Nissle 1917-CM is TLR-2 dependent. The differential reaction of circulating and tissue-bound T cells towards E. coli Nissle 1917 may explain the beneficial effect of E. coli Nissle 1917 in intestinal inflammation. E. coli Nissle 1917 may downregulate the expansion of newly recruited T cells into the mucosa and limit intestinal inflammation, while already activated tissue-bound T cells may eliminate deleterious antigens in order to maintain immunological homeostasis.

Escherichia coli Nissle 1917 distinctively modulates T-cell cycling and expansion via toll-like receptor 2 signaling

Although the probiotic Escherichia coli strain Nissle 1917 has been proven to be efficacious for the treatment of inflammatory bowel diseases, the underlying mechanisms of action still remain elusive. The aim of the present study was to analyze the effects of E. coli Nissle 1917 on cell cycling and apoptosis of peripheral blood and lamina propria T cells (PBT and LPT, respectively). Anti-CD3-stimulated PBT and LPT were treated with E. coli Nissle 1917-conditioned medium (E. coli Nissle 1917-CM) or heat-inactivated E. coli Nissle 1917. Cyclin B1, DNA content, and caspase 3 expression were measured by flow cytometry to assess cell cycle kinetics and apoptosis. Protein levels of several cell cycle and apoptosis modulators were determined by immunoblotting, and cytokine profiles were determined by cytometric bead array. E. coli Nissle 1917-CM inhibits cell cycling and expansion of peripheral blood but not mucosal T cells. Bacterial lipoproteins mimicked the effect of E. coli Nissle 1917-CM; in contrast, heat-inactivated E. coli Nissle 1917, lipopolysaccharide, or CpG DNA did not alter PBT cell cycling. E. coli Nissle 1917-CM decreased cyclin D2, B1, and retinoblastoma protein expression, contributing to the reduction of T-cell proliferation. E. coli Nissle 1917 significantly inhibited the expression of interleukin-2 (IL-2), tumor necrosis factor alpha, and gamma interferon but increased IL-10 production in PBT. Using Toll-like receptor 2 (TLR-2) knockout mice, we further demonstrate that the inhibition of PBT proliferation by E. coli Nissle 1917-CM is TLR-2 dependent. The differential reaction of circulating and tissue-bound T cells towards E. coli Nissle 1917 may explain the beneficial effect of E. coli Nissle 1917 in intestinal inflammation. E. coli Nissle 1917 may downregulate the expansion of newly recruited T cells into the mucosa and limit intestinal inflammation, while already activated tissue-bound T cells may eliminate deleterious antigens in order to maintain immunological homeostasis.

Medical Therapy of Crohn's Disease

There is no medical or surgical treatment that provides a permanent cure for Crohn's disease (CD). However, an evolving understanding of the pathogenesis of CD has provided clinicians with a diversity of medical treatment options for the disease. The goal of therapy is to induce and maintain clinical remission. The efficacy of immune-modifying agents such as azathioprine/6-mercaptopurine and infliximab have supported a paradigm shift in CD treatment in which maintenance agents are introduced earlier in the disease course. At the same time, it is imperative to balance the efficacy, safety, and tolerability of medical therapy. Given the variable and relapsing clinical course of CD, the physician and patient should ideally develop an ongoing relationship that allows for individualization of treatment regimens, monitoring of response and side effects, and modification of the therapeutic strategy in the absence of improvement.

Refractory Inflammatory Bowel Disease

Therapeutic options for refractory colonic inflammation in patients with ulcerative colitis or Crohn's disease have recently been expanded with the introduction of biologic therapies. Intravenous corticosteroids and cyclosporine A remain the standard therapies for severe ulcerative colitis. Monoclonal antibodies directed at tumor necrosis factor-a have proven to be exceptionally efficacious in patients with severe or refractory Crohn's disease. Immunomodulatory therapy with azathioprine, 6-mercaptopurine, or methotrexate has demonstrated efficacy for maintenance of remission in patients with refractory ulcerative colitis or Crohn's disease. The use of experimental biologic agents may be considered for those patients who fail to respond to or remain dependent on corticosteroids. Surgical intervention still remains for patients with severe colitis who fail to respond to medical therapy or develop life-threatening complications such as perforation or toxic megacolon.

Hydrogen peroxide contributes to motor dysfunction in ulcerative colitis

Ulcerative colitis (UC) affects colonic motor function, but the mechanism responsible for this motor dysfunction is not well understood. We have shown that neurokinin A (NKA) may be an endogenous neurotransmitter mediating contraction of human sigmoid colonic circular muscle (HSCCM). To elucidate factors responsible for UC motor dysfunction, we examined the role of hydrogen peroxide (H(2)O(2)) in the decrease of NKA-induced response of HSCCM. As previously demonstrated, NKA-induced contraction or Ca(2+) increase of normal muscle cells is mediated by release of Ca(2+) from intracellular stores, because it was not affected by incubation in Ca(2+)-free medium (CFM) containing 200 microM BAPTA. In UC, however, CFM reduced both cell contraction and NKA-induced Ca(2+) increase, suggesting reduced Ca(2+) release from intracellular stores. In normal Ca(2+) medium, NKA and KCl caused normal Ca(2+) signal in UC cells but reduced cell shortening. The decreased Ca(2+) signal and contraction in response to NKA or thapsigargin were partly recovered in the presence of H(2)O(2) scavenger catalase, suggesting involvement of H(2)O(2) in UC-induced dysmotility. H(2)O(2) levels were higher in UC than in normal HSCCM, and enzymatically isolated UC muscle cells contained much higher levels of H(2)O(2) than normal cells, which were significantly reduced by catalase. H(2)O(2) treatment of normal cells in CFM reproduced the reduction of NKA-induced Ca(2+) release observed in UC cells. In addition, H(2)O(2) caused a measurable, direct release of Ca(2+) from intracellular stores. We conclude that H(2)O(2) may contribute to reduction of NKA-induced Ca(2+) release from intracellular Ca(2+) stores in UC and contribute to the observed colonic motor dysfunction.

Infliximab-induced lupus in Crohn's disease: a case report

An 18-year-old male patient was under treatment with infliximab at a dose of 5 mg/kg at Weeks 0, 2 and 6 for refractory Crohn's disease. In June 2002, the patient was admitted to the Outpatient Clinic of the Rheumatology Unit for arthralgia affecting the small joints, non-pruritic crops of purple skin lesions and malar rash in the face. Serum antinuclear antibodies were positive (1:640 speckled pattern), and anti-double-stranded DNA was positive (1:80); moreover, positivity of anti-extractable nuclear antigen was observed. Antihistone antibodies, lupus anticoagulant and anticardiolipin antibodies were negative. A diagnosis of infliximab-induced lupus was made and the drug treatment was withdrawn. However, 3 months after withdrawal of treatment, the patient still showed clinical and laboratory symptoms of systemic lupus erythematosus. After 6 months of treatment, systemic lupus erythematosus-related symptoms disappeared and anti-double-stranded DNA returned to normal. The patient is currently under treatment with prednisone 20 mg/day for systemic lupus erythematosus and with oral mesalazine 2.4 mg/day for Crohn's disease. Treatment with infliximab is known to produce an increase of autoantibodies (antinuclear antibodies, anti-double-stranded DNA), but not clinical disease. This is the first case, to our knowledge, of onset of prolonged infliximab-induced lupus.

Inflammatory Bowel Disease After Age 60

New-onset idiopathic inflammatory bowel disease (IBD) is not uncommon among the elderly, although more common are colonic infection, ischemia, or neoplasia, all of which may mimic IBD. Although the clinical presentation of IBD in the elderly often resembles that of younger subjects, atypical manifestations are common and may lead to difficulty in diagnosis. Much progress has been made in both medical and surgical therapy for IBD, but such therapy poses additional challenges in the elderly, who are more likely to experience adverse effects of medications or complications of surgery. The elderly generally have a favorable outcome to both medical and surgical therapy for IBD. Although concern about possible untoward effects of therapy is warranted, treatment should not be withheld because of fear of complications.

Substance P (NK(1)) receptor expression by human colonic epithelial cell line Caco-2

The peptide substance P (SP) is known to take part in the regulation of the Cl(-)-dependent secretion in the animal and human colonic mucosa. However, no conclusive evidence for the expression of the functional tachykinin NK(1) receptor has been found in the human colonic epithelial cells. Using the reverse transcription-polymerase chain reaction (RT-PCR) method we could detect the transcripts of the NK(1) receptor in the human colonic epithelial cell line Caco-2. Furthermore, we characterized the mechanism of substance P-induced intracellular signaling in Caco-2 cells. While substance P had no effect on intracellular calcium concentration as measured by fura-2 AM, it induced the activation of the mitogen-activated protein kinases (MAPKs) in a time- and dose-dependent manner. Surprisingly, the peptide NK(1) receptor antagonist [D-Pro(2), D-Trp(7,9)]SP stimulated the activity of MAPKs in the same manner as substance P. In contrast, the specific nonpeptide NK(1) receptor antagonist CP-96,345 clearly abolished the effect of substance P and [D-Pro(2), D-Trp(7,9)]SP on MAPK activity. CP-96,345 itself did not increase the activity of MAPKs. Thus, we provide the first evidence that a functional NK(1) receptor is expressed in the human colonic epithelial cell line Caco-2. The results show that in Caco-2 cells the peptide antagonist [D-Pro(2), D-Trp(7,9)]SP acts as a NK(1) receptor agonist in contrast to the nonpeptide antagonist CP-96,345.

Early experience with laparoscopic ileal pouch-anal anastomosis for ulcerative colitis

The purpose of this study was to describe our minimally invasive technique and outline perioperative and medium-term outcomes in patients undergoing laparoscopic ileal pouch-anal anastomosis (LIPAA) for ulcerative colitis. Data were obtained from a prospectively collected database of 13 LIPPA procedures performed for ulcerative colitis between May 1994 and November 2000. Medium-term quality-of-life follow-up was obtained by telephone interview. Eight males and five females had an LIPAA performed, all of whom had previously undergone total abdominal colectomy with ileostomy. Median operative time was 255 minutes (range, 200-398 minutes) with one conversion (8%) due to adhesions. There were no deaths or intraoperative complications; however, six patients experienced seven postoperative complications within 30 days of final closure of defunctioning ileostomy (two leaks, two wound infections, one pulmonary embolus, and two reoperations for small bowel obstruction). Median length of stay was 7 days (range, 5-13 days). Median follow-up was 24 months (range, 6-66 months). The median number of day and night bowel movements was 6.0 (range, 3-10) and 1.0 (range, 0-3), respectively, with five patients requiring medication to control frequency. None had incontinence of stool or retrograde ejaculation; however, one had occasional incontinence of gas, three had occasional nocturnal soiling, and one was impotent. Three patients (23%) had pouchitis, all treated successfully with oral antibiotics. All patients were satisfied with the outcome of their operation and all preferred their pouch to previous ileostomy. Patients reported their overall social, emotional, and physical well being to be satisfactory to excellent. Results of the SF-36, a generic quality-of-life survey, were similar to those from studies of patients following an open pelvic pouch procedure. The LIPAA is technically feasible in experienced centers. We believe that the technique is still evolving and that more time and experience is required to refine the procedure.

Peroxisome proliferator-activated receptor gamma agonist ligands stimulate a Th2 cytokine response and prevent acute colitis

Peroxisome proliferator-activated receptor gamma (PPARgamma), a member of a nuclear transcription factor family, has been previously demonstrated to have antiinflammatory activity. The effects of PPARgamma activation in the development of an immune response are less well characterized. Through evaluation of PPARgamma heterozygote mice (PPARgamma(+/-) and specific PPARgamma agonist ligand binding, we evaluated the immunologic effects of PPARgamma activation in a well-described model of colitis. Increased susceptibility to dextran sodium sulfate (DSS)-induced colitis as defined by body weights, histologic injury, and survival was observed in the PPARgamma(+/-) mice in comparison to wild-type mice. Three different PPARgamma ligands (troglitazone, pioglitazone, and rosiglitazone) demonstrated beneficial dose-related treatment effects when administered prior to the onset of colitis. However, no protection was observed when PPARgamma ligand activation occurred after the onset of colitis. The reduction in DSS-induced inflammation noted with PPARgamma ligand treatment was associated with decreased interferon-gamma and tumor necrosis factor-alpha and increased interleukin (IL)-4 and IL- 10 levels as assessed by quantitative reverse transcriptase-polymerase chain reaction. Consistent with this shift towards a T helper (Th2) cytokine dominance, PPARgamma ligand treatment stimulated increased GATA-3 expression. These results indicate that the protective effects exhibited by PPARgamma ligands in intestinal inflammation may be due to immune deviation away from Th1 and towards Th2 cytokine production.

Review article: the limitations of corticosteroid therapy in Crohn's disease

Corticosteroids are highly effective in inducing clinical remission in patients with active Crohn's disease. However, the role of corticosteroids in the treatment of this disease is primarily ameliorative because they are ineffective in maintaining remission or healing mucosal lesions. Nearly half of the patients who initially respond to corticosteroid therapy develop a dependency on corticosteroids or have a relapse within 1 year. In addition, use of these agents is often limited by a relatively high risk of serious adverse effects that can involve nearly every major body system. These effects include: bone loss, which can develop with even short-term and low-dose corticosteroid therapy; metabolic complications such as glucose intolerance and diabetes mellitus; increased intraocular pressure and glaucoma; and potentially lethal infections. To minimize the risk of toxicity, corticosteroids are increasingly recommended for short-term use only at the lowest effective dose to induce remission in patients with moderately to severely active Crohn's disease. Corticosteroid formulations with low systemic bioavailability, such as controlled-release budesonide, may be associated with a lower rate of dermatologic adverse effects but appear to be somewhat less effective than conventional corticosteroids in inducing remission in patients with active Crohn's disease. Immunosuppressive agents such as azathioprine, 6-mercaptopurine, and methotrexate have demonstrated corticosteroid-sparing effects, facilitating the withdrawal of corticosteroids when initiated as maintenance therapy. Infliximab can be used as an alternative to corticosteroids.

Integrating anti-tumor necrosis factor therapy in inflammatory bowel disease: current and future perspectives

Crohn's disease and ulcerative colitis are two idiopathic inflammatory disorders of the GI tract. Manifestations of disease can be severe and lead to long term therapy with a variety of medications and/or surgery. Standard medical therapy consists of agents that either treat suppurative complications or modulate the inflammatory cascade in a nonspecific manner. Many specific chemokine and cytokine effectors that promote intestinal inflammation have been identified. Such work has led to experimental clinical trials with a variety of cytokine antagonists. Compounds directed against one such cytokine, tumor necrosis factor alpha (TNF), have demonstrated the greatest clinical efficacy to date. This is consistent with scientific observations that suggest a central role for TNF in the inflammatory cascade. Infliximab is a chimeric monoclonal antibody against TNF that has been demonstrated to be effective for the treatment of Crohn's disease. Infliximab is Food and Drug Administration approved for the treatment of Crohn's disease. There exist several other TNF antagonists in various phases of investigation, including the monoclonal antibody CDP 571, the fusion peptide etanercept, the phosphodiesterase inhibitor oxpentifylline, and thalidomide. The clinical efficacy of these agents and the role of TNF in the pathogenesis of inflammatory bowel disease is reviewed.

Refractory Inflammatory Bowel Disease

Therapeutic options for refractory colonic inflammation in patients with ulcerative colitis or Crohn's disease have recently been augmented by the introduction of biologic therapies. Intravenous corticosteroids and cyclosporin A remain the standard therapies for severe ulcerative colitis. Monoclonal antibodies directed at tumor necrosis factor alfa (TNF-alpha) have proven to be most efficacious in patients with severe or refractory Crohn's disease. Immunomodulatory therapy with azathioprine, 6-mercaptopurine, or methotrexate has demonstrated efficacy for maintenance of remission in patients with refractory ulcerative colitis or Crohn's disease. The use of experimental biologic agents may be considered for those patients who fail to respond to or remain dependent on corticosteroids. Surgical intervention is indicated for patients with severe colitis who fail to respond to medical therapy or develop life-threatening complications such as perforation or toxic megacolon.

IL-10 kinetics in thyroiditis-prone BB/Wor rats

Cytokines modulate the course of autoimmunity, but their role in the evolution of spontaneous disease is unclear. This study compared the cytokine kinetics of T cell cultures from thyroiditis (LT)-prone NB line BB/Wor rats with those of Wistar (Wis) rat controls following activation with the thyroid-specific antigen thyroglobulin (Tg) or Concanavalin A (Con A).

DESIGN

T cell enhanced splenocytes from 60 day old Wis and NB rats were activated with 0.5 microg/ml rat thyroglobulin (Tg) or Con A in the presence of homologous irradiated splenocytes as antigen presenting cells (APC's). In addition, the effect of APC's was determined in a crisscross experiment which examined NB T cell responses to Con A in the presence of Wis APC's. ELISA and RT-PCR were used to examine IL-2, IL-4, IL-10, TNFalpha, IFNgamma, IL-I0 concentrations and mRNA expression in the supernatant and cells from parallel cultures harvested at specific intervals. Frozen thyroids from 60 day old NB, Wis and Fisher rats were examined for the presence of IL-10 by immunohistochemistry. T cell proliferation was measured by 3H thymidine uptake.

RESULTS

Following activation with either Tg or Con A, IL-10 concentrations exceeded IFNgamma in NB rat cultures, but IFNgamma exceeded IL-10 in Wis cultures. Wis splenocytes significantly enhanced NB T cell proliferation and cytokine responses to Con A. Thyroids from 60 day NB rats contained IL-10, but no IFNgamma. There was no IL-10 in thyroids from Wistar or Fisher rats.

CONCLUSION

Splenocyte responses in LT-prone BB/Wor rats favor IL-10 production. Future investigations will examine the source of intrathyroidal IL-10 and its role in LT.

Update in medical treatment of Crohn's disease

Crohn's disease is an inflammatory bowel disorder that has no known cause. The goal of medical treatment is to control active disease, induce and maintain clinical remission, and treat complications. Anti-inflammatory medications and immunomodulatory therapies are the primary treatment modalities for Crohn's disease. The categories of standard treatment include the 5-aminosalicylic acid compounds, corticosteroids, antibiotics, and immunomodulators. New biologic therapy has been developed to better target the immune mediators that are active in Crohn's disease. Infliximab is the first of the biologic agents approved for the treatment of fistulizing and active Crohn's disease. Despite medical advances in treatment, there is still no cure for Crohn's disease.

Therapy of inflammatory bowel disease

In the last decade, substantial gains have been made in the treatment of inflammatory bowel disease (IBD). Refinements in drug formulation have provided the ability to target distinct sites of delivery, enhancing the safety and efficacy of older agents. Immunosuppressive agents beyond corticosteroids have assumed a routine part in the care of patients with IBD. Moreover, as the century closes, we stand at the threshold of unprecedented advances in knowledge of the pathogenesis of ulcerative colitis and Crohn's disease. Simultaneous progress in biotechnology has fostered the development of new agents that strategically target pivotal processes in disease pathogenesis. This review covers agents currently used in the treatment of IBD and seeks to provide an overview of emerging therapies.