Review article: aminosalicylates in inflammatory bowel disease

SHARP hydrogel for the treatment of inflammatory bowel disease

Inflammatory bowel disease (IBD) is a relapsing and remitting inflammatory disease affecting millions of people worldwide. The active phase of IBD is characterized by excessive formation of reactive oxygen species (ROS) in the intestinal mucosa, which further accelerates the inflammatory process. A feasible strategy for the IBD treatment is thus breaking the oxidation-inflammation vicious circle by scavenging excessive ROS with the use of a suitable antioxidant. Herein, we have developed a novel hydrogel system for oral administration utilizing sterically hindered amine-based redox polymer (SHARP) incorporating covalently bound antioxidant SHA groups. SHARP was prepared via free-radical polymerization by covalent crosslinking of 2-hydroxyethyl methacrylate (HEMA), poly(ethylene oxide) methyl ether methacrylate (PEGMA) and a SHA-based monomer, N-(2,2,6,6-tetramethyl-piperidin-4-yl)-methacrylamide. The SHARP hydrogel was resistant to hydrolysis and swelled considerably (∼90% water content) under the simulated gastrointestinal tract (GIT) conditions, and exhibited concentration-dependent antioxidant properties in vitro against different ROS. Further, the SHARP hydrogel was found to be non-genotoxic, non-cytotoxic, non-irritating, and non-absorbable from the gastrointestinal tract. Most importantly, SHARP hydrogel exhibited a statistically significant, dose-dependent therapeutic effect in the mice model of dextran sodium sulfate (DSS)-induced acute colitis. Altogether, the obtained results suggest that the SHARP hydrogel strategy holds a great promise with respect to IBD treatment.

Mesalazine Suppresses Proinflammatory Cytokines in Patients with Acute Anterior Uveitis Independently of HLA-B27

Purpose: The aim is to unravel the mechanism of mesalazine (5-ASA) on proinflammatory cytokines in PBMCs of patients with HLA-B27 +and HLA-B27 -acute anterior uveitis (AAU), and whether this may explain the different effects of 5-ASA in both disoders.Methods: PBMCs from 12 HLA-B27+ and 4 HLA-B27- AAU patients were preincubated with 5-ASA and stimulated with LPS. As mesalazine (5-ASA) could be involved in ER stress, proinflammatory and ER stress-associated cytokines and markers were measured.Results: Mesalazine (5-ASA) suppressed IL-6 mRNA in healthy donors and in HLA-B27+ and HLA-B27- patients but did not lead to induction and secretion of IL-1β. In HLA-B27 + or - patients the ER stress-associated markers CHOP (DDIT3) and ATF6 were suppressed.Conclusions: Here we show that mesalazine (5-ASA) inhibits the transcription of proinflammatory and (ER) stress associated cytokines and markers, independently of the HLA-B27 status. Results show the similarities of both AAU types but do not decipher the mechanism why the HLA-B27 status determines the therapeutic response to mesalazine in AAU.

Similar pharmacokinetics of three dosing regimens comprising two oral delayed-release mesalamine formulations in healthy adult volunteers: Randomised, open-label, parallel-group study

Aims

Mesalamine is the first‐line therapy for treating mild‐to‐moderate ulcerative colitis. Multiple mesalamine formulations are available, with similar safety and efficacy profiles. Mesalamine is commonly administered as divided dosing, although once‐daily dosing may provide benefits for patients. We evaluated the pharmacokinetics of three dosing regimens of two oral delayed‐release mesalamine formulations in healthy adult volunteers.

Methods

A randomised, open‐label, parallel‐group study of mesalamine pharmacokinetics following Lialda 2 × 1.2 g once daily (QD) (dose A), Asacol 6 × 400 mg QD (dose B), or Asacol 2 × 400 mg three times daily (TID) (dose C) over 7 days. Assessments included 5‐aminosalicylic acid (5‐ASA) and N‐acetyl 5‐aminosalicylic acid (N‐Ac‐5‐ASA, primary metabolite) pharmacokinetics (A_e(%), AUC_0‐24 and C_max), safety and tolerability.

Results

All enrolled volunteers (n = 37) completed the study. Steady state was achieved for all treatments by day 4. Ratios (95% CI) of means for steady‐state AUC_0‐24 (dose A vs B 90.3% [39.8, 204.8], dose A vs C 123.5% [55.3, 275.7], dose B vs C 136.8% [61.3, 305.5]) and C_max (dose A vs B 106.0% [46.4, 242.2], dose A vs C 133.0% [59.1, 299.0], dose B vs C 125.5% [55.8, 282.1]) were similar for all 5‐ASA treatments. Mean urinary excretion of 5‐ASA plus N‐Ac‐5‐ASA was comparable between treatments (dose A 21.3%, dose B 20.2%, dose C 17.9%). All treatment regimens were well tolerated; no safety issues were observed.

Conclusions

Plasma and urine pharmacokinetics for Asacol TID, Asacol QD, and Lialda QD are similar, suggesting similar daily systemic exposures can be obtained with either TID or QD dosing. NCT00751699.

Colitis and Crohn's Foundation (India) consensus statements on use of 5-aminosalicylic acid in inflammatory bowel disease

Despite several recent advances in therapy in inflammatory bowel disease (IBD), 5-aminosalicylic acid (5-ASA) therapy has retained its place especially in ulcerative colitis. This consensus on 5-ASA is obtained through a modified Delphi process, and includes guiding statements and recommendations based on literature evidence (randomized trials, and observational studies), clinical practice, and expert opinion on use of 5-ASA in IBD by Indian gastroenterologists. The aim is to aid practitioners in selecting appropriate treatment strategies and facilitate optimal use of 5-ASA in patients with IBD.

Natural history of children with mild Crohn’s disease

BACKGROUND

There is a small and poorly studied population of patients with mild and limited Crohn’s disease (CD), who either spontaneously enter remission and can discontinue therapy, or be maintained on milder anti-inflammatory treatment.

AIM

To identify a group of children with mild CD who were not escalated to immunomodulators (azathioprine, mercaptopurine, or methotrexate) or biologics (infliximab or adalimumab) within the first two years after their Crohn’s diagnosis and outline the natural history and phenotypic features of these patients.

METHODS

In a retrospective chart review of the inflammatory bowel disease database at Boston Children’s Hospital we reviewed all the mild CD patient’s clinic visits, laboratory studies, and procedures for the duration of time they were followed at the center. Patients were included if they had clear diagnosis of Crohn’s disease, and they were not escalated to immunosuppressive therapies for at least 2 years after the date of diagnosis. These mild CD patients were compared to controls diagnosed at a similar time, that were treated with immunomodulators or biologics. Data that was abstracted included: Age at diagnosis, sex, disease location utilizing the Paris classification, medical treatment, surgical treatment, endoscopic findings, histology, and hospitalizations. We also analyzed differences in the phenotypic features between those with mild CD and those with moderate to severe disease.

RESULTS

Out of 1205 patients with CD diagnosed between 1990 and 2013, we identified 29 patients that met the inclusion criteria, and they were matched with 58 controls. There were no significant differences between the disease behaviors at presentation, with approximately 90% of patients in each group having inflammatory disease. However, patients with mild disease were more likely to have disease limited to the colon (31% vs 12%, P = 0.03). In contrast, patients with moderate to severe disease (aka control group) were more likely to have ileocolonic disease (70% vs 45% in the mild group, P = 0.02). Of the 29 patients, only 8 required medication escalation to immunomodulators during the period of follow-up. The primary indication for escalation to immune suppressive therapies was corticosteroid dependence. We also found that patients treated without immunomodulators or biologics for mild CD continue to exhibit histologic intestinal inflammation. Of the 29 patients, three developed significant complications of ileal disease, though only one required surgical intervention during the period of follow-up.

CONCLUSION

We identified a cohort of children with mild CD, who were able to avoid the institution of immune suppressive therapies for several years, and generally had good outcomes during the period of follow-up. While a subset of these patients will eventually require either immunosuppression or surgery, the majority of them have a good quality of life despite having low-grade intestinal inflammation. Importantly, this subset of patients has managed to avoid the potential toxicities of immune suppression for several years. The majority of these patients have either colonic disease with minimal small bowel involvement or limited ileal disease.

Transcriptomic analysis reveals a controlling mechanism for NLRP3 and IL-17A in dextran sulfate sodium (DSS)-induced colitis

The incidence of inflammatory bowel disease (IBD) has markedly increased. Our research findings during the past showed that medicinal plant extracts and the derived phytochemical components from Wedelia chinensis (WC) can have strong anti-colitis activities. Here, we further identified the key component phytochemicals from active fractions of different WC preparations (WCHA) that are responsible for the protective effect of WCHA in colitis mice. Of the 3 major compounds (wedelolactone, luteolin and apigenin) in this fraction, luteolin had the highest anti-inflammatory effect in vivo. Using a next-generation sequencing (NGS) (e.g., RNA-seq) system to analyze the transcriptome of colorectal cells/tissues in mice with dextran sulfate sodium (DSS)-induced colitis with/without phytochemicals treatment, luteolin was found to strongly suppress the DSS-activated IL-17 pathway in colon tissue. In addition, co-treatment with wedelolactone and luteolin had a synergistic effect on the expression level of some IL-17 pathway-related genes. Interestingly, our NGS analyses also indicated that luteolin and wedelolactone can specifically suppress the expression of NLRP3 and NLRP1. Using a 3-dimensional cell co-culture system, we further demonstrated that luteolin could efficiently suppress NLRP3 expression via disruption of IL-17A signaling in inflamed colon tissue, which also indicates the pharmacological potential of luteolin and wedelolactone in treating IBD.

Other immunomodulatory agent-related lymphoproliferative diseases: a single-center series of 72 biopsy-confirmed cases

Ongoing development of new drugs, as well as novel indications in the treatment of autoimmune diseases leads to the increasing use of immunomodulatory and immunosuppressive drugs. Immunomodulatory agent-related lymphoproliferative disorders are a known and potentially life threatening complication of chronic administration of these drugs, but are less well characterized compared with post-transplant lymphoproliferative disorders. The heterogeneous drug targets, various underlying disease indications, different drug combinations used and relatively low incidence render data collection and interpretation difficult. In this retrospective paper, we describe the clinicopathological characteristics of a larger single-center series of 72 immunomodulatory agent-related lymphoproliferative disorder cases. We divided the cases according to the therapy, administered in the year preceding diagnosis of a lymphoproliferative disorder, in an immunosuppressive drug, an immunomodulatory drug and a combination of immunosuppressive and immunomodulatory drugs group. We observed differences in "time to lymphoproliferative disorder development" with a shorter time for all the immunomodulatory drug-related cases combined (immunomodulatory and immunomodulatory + immunosuppressive = immunomodulatory-all) vs immunosuppressive-only (p = 0.0031). The proportion of malignant cases in patients receiving immunomodulatory therapy was, however, also significantly lower when compared with the immunosuppressive treated cases (43 vs 88%; p = 0.0184). The immunomodulatory/suppressive agent-related lymphoproliferative disorders were less often associated with the Epstein-Barr virus (EBV) (31 vs 66%; p = 1.829e-05) and the lymphoproliferative disorders incidence in the first year after immunomodulatory/immunosuppressive therapy initiation was lower (18 vs 41%; p = 0.04151)-compared with a published series of 140 post-transplant lymphoproliferative disorder cases from the same center. However, a similar histopathological spectrum from nondestructive, to polymorphic and monomorphic lesions as in post-transplant lymphoproliferative disorders is observed. With increasing use of immunosuppressive and especially immunomodulatory therapy, a higher incidence of immunomodulatory/suppressive agent-related lymphoproliferative disorders is to be expected. Life-long awareness for development of immunomodulatory/suppressive agent-related lymphoproliferative disorders with clinical follow-up and timely biopsies of suspicious lesions is required since these lymphoproliferative disorders arise both early after therapy initiation and many years later. Histopathological confirmation and correct classification is necessary to guide therapy and EBV ISH should be a part of routine pathological diagnostics.

Novel Gene Encoding 5-Aminosalicylate 1,2-Dioxygenase from Comamonas sp. Strain QT12 and Catalytic Properties of the Purified Enzyme

The 1,125-bp mabB gene encoding 5-aminosalicylate (5ASA) 1,2-dioxygenase, a nonheme iron dioxygenase in the bicupin family that catalyzes the cleavage of the 5ASA aromatic ring to form cis-4-amino-6-carboxy-2-oxohexa-3,5-dienoate in the biodegradation of 3-aminobenzoate, was cloned from Comamonas sp. strain QT12 and characterized. The deduced amino acid sequence of the enzyme has low sequence identity with that of other reported ring-cleaving dioxygenases. MabB was heterologously expressed in Escherichia coli cells and purified as a His-tagged enzyme. The optimum pH and temperature for MabB are 8.0 and 10°C, respectively. Fe^II is required for the catalytic activity of the purified enzyme. The apparent K_m and V_max values of MabB for 5ASA are 52.0 ± 5.6 μM and 850 ± 33.2 U/mg, respectively. The two oxygen atoms incorporated into the product of the MabB-catalyzed reaction are both from the dioxygen molecule. Both 5ASA and gentisate could be converted by MabB; however, the catalytic efficiency of MabB for 5ASA was much higher (∼70-fold) than that for gentisate. The mabB-disrupted mutant lost the ability to grow on 3-aminobenzoate, and mabB expression was higher when strain QT12 was cultivated in the presence of 3-aminobenzoate. Thus, 5ASA is the physiological substrate of MabB.IMPORTANCE For several decades, 5-aminosalicylate (5ASA) has been advocated as the drug mesalazine to treat human inflammatory bowel disease and considered the key intermediate in the xenobiotic degradation of many aromatic organic pollutants. 5ASA biotransformation research will help us elucidate the microbial degradation of these pollutants. Most studies have reported that gentisate 1,2-dioxygenases (GDOs) can convert 5ASA with significantly high activity; however, the catalytic efficiency of these enzymes for gentisate is much higher than that for 5ASA. This study showed that MabB can convert 5ASA to cis-4-amino-6-carboxy-2-oxohexa-3,5-dienoate, incorporating two oxygen atoms from the dioxygen molecule into the product. Unlike GDOs, MabB uses 5ASA instead of gentisate as the primary substrate. mabB is the first reported 5-aminosalicylate 1,2-dioxygenase gene.

Gynostemma pentaphyllum saponins attenuate inflammation in vitro and in vivo by inhibition of NF-κB and STAT3 signaling

Recent advances in the development of anti-inflammatory agents have improved their therapeutic outcome in inflammatory bowel disease (IBD), however, the presence of side effects and limited effectiveness hinder their widespread use. Therefore, novel compounds with strong anti-inflammatory efficacy are still required. In this study, we investigated the anti-inflammatory effect and potential mechanisms of Gynostemma pentaphyllum (Thunb.) Makino saponins (GpS), a major component of the herbal medicine widely used in Asian countries. In in vitro studies, we demonstrated that GpS dose dependently suppressed activation of macrophages, one of the main effectors in IBD. GpS also suppressed cytokine production and the activation of NF-κB and STAT3 signaling in lipopolysaccharide-induced macrophages, without affecting their viability. Further in vivo studies demonstrated that GpS could ameliorate the weight loss, increased disease activity index, colon shortening and histological damage associated with dextran sulfate sodium (DSS)-induced colitis in mice. In agreement with results from our in vitro experiments, GpS suppressed cytokine production and activation of NF-κB and STAT3 signaling in the colons of DSS-induced mice.

In this study, we present for the first time, evidence of the therapeutic effect of GpS in IBD, highlighting its potential as an effective therapeutic against the disease.

Sphingolipids in neutrophil function and inflammatory responses: Mechanisms and implications for intestinal immunity and inflammation in ulcerative colitis

Bioactive sphingolipids are regulators of immune cell function and play critical roles in inflammatory conditions including ulcerative colitis. As one of the major forms of inflammatory bowel disease, ulcerative colitis pathophysiology is characterized by an aberrant intestinal inflammatory response that persists causing chronic inflammation and tissue injury. Innate immune cells play an integral role in normal intestinal homeostasis but their dysregulation is thought to contribute to the pathogenesis of ulcerative colitis. In particular, neutrophils are key effector cells and are first line defenders against invading pathogens. While the activity of neutrophils in the intestinal mucosa is required for homeostasis, regulatory mechanisms are equally important to prevent unnecessary activation. In ulcerative colitis, unregulated neutrophil inflammatory mechanisms promote tissue injury and loss of homeostasis. Aberrant neutrophil function represents an early checkpoint in the detrimental cycle of chronic intestinal inflammation; thus, dissecting the mechanisms by which these cells are regulated both before and during disease is essential for understanding the pathogenesis of ulcerative colitis. We present an analysis of the role of sphingolipids in the regulation of neutrophil function and the implication of this relationship in ulcerative colitis.

Oral 5-aminosalicylic acid for maintenance of medically-induced remission in Crohn's disease

BACKGROUND

The prevention of relapse is a major issue in the management of Crohn's disease. Corticosteroids, the mainstay of treatment of acute exacerbations, are not effective for maintenance of remission and its chronic use is limited by numerous adverse events. Randomised controlled trials assessing the efficacy of oral 5-aminosalicylic acid (5-ASA) agents for maintenance of medically-induced remission in Crohn's disease have produced conflicting results.

OBJECTIVES

To conduct a systematic review to evaluate the efficacy and safety of oral 5-ASA agents for the maintenance of medically-induced remission in Crohn's disease.

SEARCH METHODS

We searched MEDLINE, EMBASE, CENTRAL and the IBD Group Specialized Register from inception to 8 June 2016. We also searched reference lists and conference proceedings.

SELECTION CRITERIA

We included randomised controlled trials that compared oral 5-ASA agents to either placebo or sulphasalazine in patients with quiescent Crohn's disease. The trials had to have a treatment duration of at least six months.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data and performed the risk of bias assessment. Any disagreements were resolved by discussion and consensus. The primary outcome measure was the occurrence of relapse as defined by the primary studies. Secondary outcomes included time to relapse, adverse events, withdrawal due to adverse events and serious adverse events. We calculated the pooled risk ratio (RR) and corresponding 95% confidence interval (95% CI) using a fixed-effect model. All data were analysed on an intention-to-treat basis and drop-outs were considered to be relapses. Sensitivity analyses included an available case analysis where drop-outs were ignored and using a random-effects model. We evaluated the overall quality of the evidence supporting the outcomes using the GRADE criteria.

MAIN RESULTS

Twelve studies (2146 participants) that compared 5-ASA to placebo were included. We did not identify any studies that compared sulphasalazine to placebo. Seven studies were judged to be at low risk of bias. The other studies were judged to have an unclear risk of bias for various items due to insufficient details to allow for a judgement. There was no statistically significant difference in relapse rates at 12 months. Fifty-three per cent (526/998) of 5-ASA patients (dose 1.6 g to 4 g/day) relapsed at 12 months compared to 54% (544/1016) of placebo patients (RR 0.98, 95% CI 0.91 to 1.07; 11 studies; 2014 patients; moderate-quality evidence). Sensitivity analyses based on an available case analysis and a random-effects model had no impact on the results. One study found no difference in relapse rates at 24 months. Fifty-four per cent (31/57) of 5-ASA patients (dose 2 g/day) relapsed at 24 months compared to 58% (36/62) of placebo patients (RR 0.94, 95% CI 0.68 to 1.29, 119 patients; low-quality evidence). One paediatric study found no statistically significant difference in relapse rates at 12 months. Sixty-two per cent (29/47) of paediatric 5-ASA patients (dose 50 mg/kg/day) relapsed at 12 months compared to 64% (35/55) of paediatric placebo patients (RR 0.97, 95% CI 0.72 to 1.31; 102 patients; moderate-quality evidence). There was no statistically significant difference in the proportion of patients who experienced an adverse event, withdrawal due to adverse events or serious adverse events. Thirty-four per cent (307/900) of 5-ASA patients had at least one adverse event compared to 33% (301/914) of placebo patients (RR 1.05, 95% CI 0.95 to 1.17; 10 studies; 1814 patients). Fourteen per cent (127/917) of 5-ASA patients withdrew due to adverse events compared to 13% (119/916) of placebo patients (RR 1.11, 95% CI 0.88 to 1.38; 9 studies; 1833 patients). One per cent (3/293) of 5-ASA patients had a serious adverse event compared to 0.7% (2/283) of placebo patients (RR 1.43, 95% CI 0.24 to 2.83; 3 studies; 576 patients). Common adverse events reported in the studies included diarrhoea, nausea and vomiting, abdominal pain, headache and skin rash.

AUTHORS' CONCLUSIONS

We found no evidence in this review to suggest that oral 5-ASA preparations are superior to placebo for the maintenance of medically-induced remission in patients with Crohn's disease. Additional randomised trials may not be justified.

Oral pathology in inflammatory bowel disease

The incidence of inflammatory bowel diseases (IBD) - Crohn’s disease (CD) and ulcerative colitis (UC) - has been increasing on a global scale, and progressively, more gastroenterologists will be included in the diagnosis and treatment of IBD. Although IBD primarily affects the intestinal tract, extraintestinal manifestations of the disease are often apparent, including in the oral cavity, especially in CD. Specific oral manifestations in patients with CD are as follows: indurate mucosal tags, cobblestoning and mucogingivitis, deep linear ulcerations and lip swelling with vertical fissures. The most common non-specific manifestations, such as aphthous stomatitis and angular cheilitis, occur in both diseases, while pyostomatitis vegetans is more pronounced in patients with UC. Non-specific lesions in the oral cavity can also be the result of malnutrition and drugs. Malnutrition, followed by anemia and mineral and vitamin deficiency, affects the oral cavity and teeth. Furthermore, all of the drug classes that are applied to the treatment of inflammatory bowel diseases can lead to alterations in the oral cavity due to the direct toxic effects of the drugs on oral tissues, as well as indirect immunosuppressive effects with a risk of developing opportunistic infections or bone marrow suppression. There is a higher occurrence of malignant diseases in patients with IBD, which is related to the disease itself and to the IBD-related therapy with a possible oral pathology. Treatment of oral lesions includes treatment of the alterations in the oral cavity according to the etiology together with treatment of the primary intestinal disease, which requires adequate knowledge and a strong cooperation between gastroenterologists and specialists in oral medicine.

Pharmacological- and non-pharmacological therapeutic approaches in inflammatory bowel disease in adults

Inflammatory bowel diseases (IBDs) are a group of chronic inflammatory conditions mainly of the colon and small intestine. Crohn's disease (CD) and ulcerative colitis (UC) are the most frequent types of IBD. IBD is a complex disease which arises as a result of the interaction of environmental, genetic and immunological factors. It is increasingly thought that alterations of immunological reactions of the patients to their own enterable bacteria (microfilm) may contribute to inflammation. It is characterized by mucosal and sub mucosal inflammation, perpetuated by infiltration of activated leukocytes. CD may affect the whole gastrointestinal tract while UC only attacks the large intestine. The therapeutic goal is to achieve a steroid-free long lasting remission in both entities. UC has the possibility to be cured by a total colectomy, while CD never can be cured by any operation. A lifelong intake of drugs is mostly necessary and essential. Medical treatment of IBD has to be individualized to each patient and usually starts with anti-inflammatory drugs. The choice what kind of drugs and what route administered (oral, rectal, intravenous) depends on factors including the type, the localization, and severity of the patient's disease. IBD may require immune-suppression to control symptoms such as prednisolone, thiopurines, calcineurin or sometimes folic acid inhibitors or biologics like TNF-α inhibitors or anti-integrin antibodies. For both types of disease (CD, UC) the same drugs are available but they differ in their preference in efficacy between CD and UC as 5-aminosalicylic acid for UC or budesonide for ileocecal CD. As therapeutic alternative the main mediators of the disease, namely the activated pro-inflammatory cytokine producing leukocytes can be selectively removed via two apheresis systems (Adacolumn and Cellsorba) in steroid-refractory or dependent cases. Extracorporeal photopheresis results in an increase of regulatory B cells, regulatory CD8(+) T cells and T-regs Type 1. Both types of apheresis were able to induce clinical remission and mucosal healing accompanied by tapering of steroids.

Combination therapy with infliximab and thiopurine compared to infliximab monotherapy in maintaining remission of postoperative Crohn's disease

BACKGROUND AND AIMS

Infliximab is an efficacious agent used for the induction and maintenance of remission in Crohn's disease (CD), and recent studies suggested that it may also prevent the recurrence of this disease after surgery. The present study was performed to assess the efficacy and safety of infliximab in the postoperative setting, and to identify whether combination treatment with thiopurines had any additional beneficial effect as compared to mono-therapy.

METHODS

We performed a retrospective cohort study to compare the efficacy of infliximab mono-therapy and combination treatment with a thiopurine in preventing recurrence after surgery.

RESULTS

Forty-one patients who received infliximab as maintenance treatment following surgery from May 2002 to April 2010 were identified. Twenty-four were naive to infliximab, and 17 who underwent surgery during infliximab treatment were continued on it following surgery. The median follow-up period was 27 months (range 12-66 months). All patients continued infliximab as maintenance treatment, but 10 required dose intensification due to clinical recurrence. Kaplan-Meier analysis demonstrated that the use of concomitant thiopurine was correlated with the continuation of infliximab treatment at an 8-week interval (log-rank test p = 0.018). The rate of adverse event was 9.8% with no patient experiencing severe adverse reactions.

CONCLUSION

Infliximab appears to be safe and it prevented clinical recurrence after surgery. Concomitant thiopurine use predicted response toward continuation of therapy at an 8-week interval. Prospective controlled studies to assess the efficacy of combination treatment in the postoperative setting are warranted.

Relationship between azathioprine dosage, 6-thioguanine nucleotide levels, and therapeutic response in pediatric patients with IBD treated with azathioprine

BACKGROUND

Azathioprine (AZA) is commonly used to treat IBD either alone or in combination with mesalazine. However, there are relatively few studies concerning the relationship between AZA dose, thiopurine metabolite levels, and therapeutic response in pediatric patients treated with both AZA and mesalazine.

METHODS

We retrospectively investigated the relationship between AZA dose, thiopurine metabolite levels, and therapeutic response in 137 pediatric patients with IBD treated with AZA using multilevel analysis. Additional factors affecting metabolite levels and therapeutic response were also analyzed.

RESULTS

A positive correlation was observed between AZA dosage and 6-thioguanine nucleotide (6-TGN) level (P < 0.0001). Variant TPMT genotype (P < 0.001) and concomitant use of mesalazine (P < 0.001) were predictors of higher 6-TGN levels. Leukopenia (P = 0.025) and lymphopenia (P = 0.045) were associated with higher levels of 6-TGN. Poor AZA compliance affected median 6-TGN levels (P < 0.001). The frequency of patients with median 6-TGN levels >235 pmol per 8 × 10(8) red blood cells was the highest in the sustained therapeutic response group (P = 0.015). Age, sex, IBD type, and duration of AZA therapy did not influence 6-TGN levels or therapeutic effect.

CONCLUSIONS

AZA dosage is positively correlated with 6-TGN level. Higher 6-TGN levels are related to leukopenia, lymphopenia, and concurrent use of mesalazine. These results provide the rationale for monitoring metabolites to optimize drug dosing and minimize drug-related toxicity. In addition, maintenance of 6-TGN levels within a beneficial therapeutic range by direct monitoring should be helpful in attaining therapeutic efficacy, although this possibility should be verified in prospective studies.

Thiopurine metabolites variations during co-treatment with aminosalicylates for inflammatory bowel disease: Effect of N-acetyl transferase polymorphisms

AIM: To evaluate variation of the concentration of thiopurine metabolites after 5-aminosalicylate (5-ASA) interruption and the role of genetic polymorphisms of N-acetyl transferase (NAT) 1 and 2.

METHODS: Concentrations of thioguanine nucleotides (TGN) and methymercaptopurine nucleotides (MMPN), metabolites of thiopurines, were measured by high performance liquid chromatography in 12 young patients (3 females and 9 males, median age 16 years) with inflammatory bowel disease (6 Crohn’s disease and 6 ulcerative colitis) treated with thiopurines (7 mercaptopurine and 5 azathioprine) and 5-ASA. Blood samples were collected one month before and one month after the interruption of 5-ASA. DNA was extracted and genotyping of NAT1, NAT2, inosine triphosphate pyrophosphatase (ITPA) and thiopurine methyl transferase (TPMT) genes was performed using PCR assays.

RESULTS: Median TGN concentration before 5-ASA interruption was 270 pmol/8 x 10⁸ erythrocytes (range: 145-750); after the interruption of the aminosalicylate, a 35% reduction in TGN mean concentrations (absolute mean reduction 109 pmol/8 × 10⁸ erythrocytes) was observed (median 221 pmol/8 × 10⁸ erythrocytes, range: 96-427, P value linear mixed effects model 0.0011). Demographic and clinical covariates were not related to thiopurine metabolites concentrations. All patients were wild-type for the most relevant ITPA and TPMT variants. For NAT1 genotyping, 7 subjects presented an allele combination corresponding to fast enzymatic activity and 5 to slow activity. NAT1 genotypes corresponding to fast enzymatic activity were associated with reduced TGN concentration (P value linear mixed effects model 0.033), putatively because of increased 5-ASA inactivation and consequent reduced inhibition of thiopurine metabolism. The effect of NAT1 status on TGN seems to be persistent even after one month since the interruption of the aminosalicylate. No effect of NAT1 genotypes was shown on MMPN concentrations. NAT2 genotyping revealed that 6 patients presented a genotype corresponding to fast enzymatic activity and 6 to slow activity; NAT2 genotypes were not related to thiopurine metabolites concentration in this study.

CONCLUSION: NAT1 genotype affects TGN levels in patients treated with thiopurines and aminosalicylates and could therefore influence the toxicity and efficacy of these drugs; however the number of patients evaluated is limited and this has to be considered a pilot study.

Mucosal healing is associated with improved long-term outcome of maintenance therapy with natalizumab in Crohn's disease

BACKGROUND

Natalizumab is an efficacious agent for induction and maintenance of remission in patients with Crohn's disease (CD) who have failed anti-tumor necrosis factor agents. We aimed to assess the impact of endoscopic severity and mucosal healing on the long-term outcome of natalizumab treatment in CD.

METHODS

We retrospectively assessed endoscopic severity according to the Simple Endoscopic Score for Crohn's Disease in patients with CD who received natalizumab therapy. The degree of endoscopic severity before natalizumab treatment and mucosal healing after treatment and their correlation with long-term outcome were studied.

RESULTS

Thirty-two patients with CD (15 male, median age 32.5 years) receiving natalizumab underwent at least 1 colonoscopy before or during natalizumab treatment. All patients had previously failed immunomodulator(s), and 31 failed anti-tumor necrosis factor agent(s). Mean duration of natalizumab treatment was 14.1 months. Baseline Simple Endoscopic Score for CD was categorized into quartiles, and those with a greater score were less likely to respond to treatment as assessed by Kaplan-Meier survival analysis (n = 32, log-rank test, P = 0.0055). Mucosal healing (decrease of Simple Endoscopic Score for CD of >70%) was achieved in 11 of 26 patients (42.3%), and this was correlated with an improved long-term outcome (log-rank test, P = 0.0063).

CONCLUSIONS

The degree of endoscopic inflammation correlates to response to natalizumab and maintenance of remission. These findings provide prognostic information for patient management decisions.

Dietary uptake of Wedelia chinensis extract attenuates dextran sulfate sodium-induced colitis in mice

SCOPE

Traditional medicinal herbs are increasingly used as alternative therapies in patients with inflammatory diseases. Here we evaluated the effect of Wedelia chinensis, a medicinal herb commonly used in Asia, on the prevention of dextran sulfate sodium (DSS)-induced acute colitis in mice. General safety and the effect of different extraction methods on the bioactivity of W. chinensis were also explored.

METHODS AND RESULTS

C57BL/6 mice were administrated hot water extract of fresh W. chinensis (WCHF) orally for one week followed by drinking water containing 2% DSS for nine days. WCHF significantly attenuated the symptoms of colitis including diarrhea, rectal bleeding and loss of body weight; it also reduced the shortening of colon length and histopathological damage caused by colonic inflammation. Among four W. chinensis extracts prepared using different extraction techniques, WCHF showed the highest anti-colitis efficacy. Analyses of specific T-cell regulatory cytokines (TNF-α, IL-4, IFN-γ, IL-17, TGF-β, IL-12) revealed that WCHF treatment can suppress the Th1 and Th17, but not Th2, responses in colon tissues and dendritic cells of DSS-induced colitis mice. A 28-day subacute toxicity study showed that daily oral administration of WCHF (100, 500, 1000 mg/kg body weight) was not toxic to mice.

CONCLUSION

Together, our findings suggest that specific extracts of W. chinensis have nutritional potential for future development into nutraceuticals or dietary supplements for treatment of inflammatory bowel disease.

Assessment of isomalt for colon-specific delivery and its comparison with lactulose

Lactulose is used as a triggering substance in a unique colon-specific delivery technology called CODESTM. Colonic microflora degrades lactulose and forms short-chain fatty acids to activate the CODESTM system. However, lactulose has been reported to cause a Maillard-type reaction with substances containing primary or secondary amino groups that may produce carcinogenic compounds. Thus, the aim of this study was to look into the possibility to substitute lactulose with isomalt for fabrication of CODESTM. The in vitro degradation of both sugars before incorporating them into the CODESTM system was evaluated with the help of rat caecal microflora. The results showed that isomalt was less efficient with regard to its rate and extent of degradation into short-chain fatty acids by the microflora compared to lactulose. However, the in vitro dissolution study did not show a significant difference in the performance between lactulose and isomalt when they were incorporated separately in CODESTM. A similar result was also obtained in the in vivo study. Based on the above results, isomalt could be used as an alternative to lactulose for colonic delivery system utilizing the principles of CODESTM.

Natalizumab in Crohn's disease: results from a US tertiary inflammatory bowel disease center

BACKGROUND

Natalizumab is an efficacious agent for the induction and maintenance of remission in patients with Crohn's disease (CD) who have failed anti-tumor necrosis factor (TNF) agents. We aimed to assess the efficacy and safety of natalizumab outside of clinical trial at a US tertiary center.

METHODS

Retrospective case review of patients with CD receiving natalizumab.

RESULTS

Forty-nine patients with CD (28 women; median age, 33 years) receiving natalizumab from April 2008 to November 2011 were identified. Median duration of disease was 180 months (range, 36-576 months); 40 patients had ileocolonic disease, 1 had ileal disease, and 8 had colonic disease. Twenty-one patients had penetrating disease, and 28 had a history of CD-related surgical treatment. Forty-seven patients previously failed treatment with at least 1 anti-TNF agent. Median duration of natalizumab treatment was 7 months (interquartile range, 3-21.5 months). Twenty-four patients (49%) were continuing natalizumab at the time of this review, and 25 discontinued treatment because of the lack of response, side effects, or positive JC virus antibody. Seventeen patients (35%) successfully continued treatment with natalizumab for longer than 12 months, and nonpenetrating disease phenotype was identified as a predictor of longer response (compared with penetrating phenotype; P = 0.013). Nine patients (18.4%) experienced adverse effects, 5 of which were serious, but no case of progressive multifocal leukoencephalopathy occurred.

CONCLUSIONS

This is the largest series of natalizumab-treated patients with CD. Our results show that natalizumab is an efficacious and safe treatment agent for patients refractory to anti-TNF agents and that nonpenetrating disease phenotype has more durable response over time.

The potential influence of 5-aminosalicylic acid on the induction of myelotoxicity during thiopurine therapy in inflammatory bowel disease patients

OBJECTIVE

To investigate the potential influence of 5-aminosalicylic acid (5-ASA) on the induction of myelotoxicity during thiopurine therapy in inflammatory bowel disease patients.

METHODS

(a) The retrospective study included inflammatory bowel disease patients treated with azathioprine (AZA)/6-mercaptopurine (6-MP). Thiopurine methyltransferase (TPMT) activity and 6-thioguanine nucleotide (6-TGN) levels were detected at stable medication points. (b) The prospective study was performed in active disease patients: 4 weeks of AZA 50 mg/day followed by concomitant 5-ASA 3 g/day for another 4 weeks. 6-TGN was analyzed at weeks 4 and 8.

RESULTS

(a) Of the 139 retrospective study patients, 45 were on AZA/6-MP+5-ASA and 94 on AZA/6-MP alone. The myelotoxicity rates were 47 and 16%, respectively. Multivariates regression analysis indicated that the administration of concomitant 5-ASA was the only risk factor associated with myelotoxicity (odds ratio=3.45, 95% confidence interval 1.31-9.04, P=0.01). (b) Thiopurine methyltransferase activity was not significantly different between patients on AZA/6-MP+5-ASA and patients on AZA/6-MP alone (P=0.78). (c) 6-TGN levels were significantly higher in samples on AZA/6-MP+5-ASA than those on AZA/6-MP (P=0.003) alone. (d) Sixteen patients completed the prospective study. After 4 weeks on AZA 50 mg/day, 6-TGN levels of 13 patients were less than 230 pmol/8×10 RBC. After another 4 weeks' cotreatment with mesalazine 3 g/day, 12 patients had 6-TGN levels at least 230 pmol/8×10 RBC, five patients had 6-TGN levels at least 420 pmol/8×10 RBC, and two of these five patients developed myelotoxicity.

CONCLUSION

The risk of thiopurine-induced myelotoxicity markedly increases in patients treated with combined 5-ASA and 2 mg/kg/day AZA therapy, which may be correlated to the increase in 6-TGN. 50 mg daily AZA when concomitant 5-ASA might help maintain an effective 6-TGN level without increasing the risk of myelotoxicity.

The use of infliximab in the prevention of postsurgical recurrence in polysurgery Crohn's disease patients: a pilot open-labeled prospective study

PURPOSE

Crohn's disease (CD) commonly recurs after surgery, and a number of patients need repeated surgery, especially smokers and those with repeated surgeries or penetrating disease. Whether infliximab prevents postsurgical recurrence in high-risk CD remains unknown. In the present pilot open-labeled study, we investigated the safety and efficacy of scheduled infliximab, which was started early after surgery, in maintaining remission of CD patients who have undergone multiple surgeries due to penetrating disease.

METHODS

Eleven patients (nine male, two female; age range, 26-48 years) who had undergone repeated surgeries (median, 4; range, 2-5) for penetrating disease were enrolled. Two to 4 weeks after surgery, the patients were started on intravenous infliximab (5 mg/kg) at an 8-week interval. The primary end points were the proportion of patients in clinical remission at the end of the study, the rate of endoscopic/radiologic remission at 24 months, and the rate of adverse effects.

RESULTS

One patient dropped out due to non-compliance, and ten patients were eligible for analysis. Clinical remission was maintained in six of ten patients (60.0%) at the end of the study. At 24 months, four out of ten patients were in endoscopic or radiological remission (40.0%). Two patients experienced adverse effects (18.2%), one of whom elected to withdraw from the study.

CONCLUSION

The findings of no major safety concern and possible clinical benefit in our study suggest that further investigation of infliximab as a treatment for prevention of postsurgical recurrence in high-risk CD is warranted.

Clinical trial: a novel high-dose 1 g mesalamine suppository (Salofalk) once daily is as efficacious as a 500-mg suppository thrice daily in active ulcerative proctitis

BACKGROUND

Mesalamine suppositories are first-line therapy in active ulcerative proctitis; the standard regime still recommends multiple doses per day. The primary objective of this study was to show the noninferiority of once-daily administration of a novel 1 g mesalamine suppository versus thrice-daily administration of the 0.5 g mesalamine suppository.

METHODS

This was a single-blind (investigator-blinded), randomized, multicenter, comparative, Phase III clinical trial. Patients with mild to moderately active ulcerative proctitis inserted either one mesalamine 1 g suppository at bedtime or one mesalamine 0.5 g suppository thrice daily over a 6-week period. The primary endpoint was rate of remission (Disease Activity Index below 4).

RESULTS

In all, 354 patients were evaluable for safety and per-protocol analysis. The new regimen demonstrated noninferiority: The percentage of patients with remission was 87.9% for the once-daily 1 g mesalamine suppository and 90.7% for the thrice-daily 0.5 g mesalamine suppository. Each regimen resulted in prompt cessation of clinical symptoms (e.g., median time to ≤3 stools per day (all without blood): 5 days in the 1 g mesalamine once-daily and 7 days in the 0.5 g mesalamine thrice-daily group). Patients preferred applying suppositories once a day.

CONCLUSIONS

In active ulcerative proctitis the once-daily administration of a 1 g mesalamine suppository is as effective and safe, yet considerably more convenient, than the standard thrice-daily administration of a 0.5 g mesalamine suppository.

An unusual case of mesalazine intoxication: Oral and rectal overloading of the rectal suppository form

Drugs containing 5-acetylsalicylic acid (5-ASA) have been commonly used for inflammatory bowel diseases for more than half a century, but no case about overdose of suppository form of mesalazine which was taken both orally and rectally has been reported in the related literature up to now. In the present case, a 20-year-old male patient who took 14.5 g of mesalazine rectally and orally for suicide purpose is discussed. He was an ulcerative colitis patient and depressed about his illness and routine life traffic. Although it was hard for him to take the suppository form orally because of its bad taste and structure, he took it with the help of water. In the patient’s colonoscopy, diffuse hyperemia and edema extending from the anal channel to the proximal rectal mucosa and a 1.5 cm diameter ulcer expanding from anal channel through the rectum were identified. No pathology was found in the upper gastrointestinal endoscopy. Routine laboratory examination was performed and no abnormality was identified in the patient’s total blood account, biochemical parameters and full-urine examination. In the control rectoscopy applied to the patient 15 days later, recovery of the ulcer was observed and he was discharged to be followed in the psychiatry clinic.

An investigation of medication adherence to 5-aminosalicylic acid therapy in patients with ulcerative colitis, using self-report and urinary drug excretion measurements

BACKGROUND

Non-adherence to 5-aminosalicylic acid (5-ASA) medication can limit the established benefits of this therapy in ulcerative colitis (UC).

AIM

To determine rates and predictors of non-adherence to 5-ASA therapy in UC patients.

METHODS

Medication adherence was assessed using self-report data and urinary drug excretion measurements. Participants completed a study-specific questionnaire and two validated questionnaires: Beliefs about Medicine Questionnaire (BMQ)-Specific and Satisfaction with Information about Medicines Scale.

RESULTS

A total of 169 participants provided self-report adherence data; 151 also provided urine samples. Adherence rates were 111/151 (68%) according to self-report and 90/151 (60%) according to urine analysis, but the two measures were not correlated (chi(2) = 0.12, P = 0.725). Logistic regression identified a significant association between self-reported non-adherence and younger age [odds ratio (OR) for increased age 0.954, 95% confidence interval (CI) 0.932-0.976] and also doubts about personal need for medication (OR for BMQ - Specific Necessity scores 0.578, 95% CI 0.366-0.913). For non-adherence based on urine analysis, only South Asian ethnicity was independently associated with non-adherence (OR 2.940, 95% CI 1.303-6.638).

CONCLUSIONS

Our observations confirm the difficulty of accurately assessing medication adherence. Nonmodifiable (younger age, South Asian ethnicity) and potentially modifiable (medication beliefs) predictors of non-adherence were identified.

Mechanical Performance of Generic and Proprietary Enema Bottles

Enemas containing the anti-inflammatory drug mesalamine are an effective treatment for a distal form of inflammatory bowel disease (IBD). An IBD patient discovered that a generic mesalamine enema was more difficult and painful to use than the proprietary version. A study was initiated to determine whether these differences were measurable in the laboratory using conventional mechanical test equipment. Differences among three bottle types (the proprietary brand and two generic versions) were quantified by mechanical testing. The compressive force required to squeeze the drug from each bottle was measured, tensile testing was performed on the bottle wall, and stiffness of the nozzle tips was studied via bend testing. The thickness of the bottle walls and the inner diameter (ID) of the nozzles were also recorded. The work required to expel the drug from the generic versions during bottle compression was significantly greater than for the proprietary (p<0.01). This was likely due to the wall thickness being greater in the generics; the elastic moduli of the three bottles were similar. The ID of the nozzles was smaller for the generic bottles, suggesting additional resistance to flow. Increased flow resistance was also observed for bottles in which lubricant obstructed the nozzle opening. The work required to bend the nozzle was greater in the generics than in the proprietary (p<0.01). These differences between the generic and proprietary bottles are consistent with the patient’s subjective experience. Poor bottle performance may adversely affect patient compliance with this treatment. Improved bottle design (such as tighter tolerances for wall thickness, nozzle ID, and nozzle stiffness) and manufacturing controls (e.g., preventing the nozzle lubricant from impeding delivery of the drug) could be achieved through the development of a standard specification for enema bottles. An optimal bottle design is suggested.

Mesalamine with MMX technology for the treatment of ulcerative colitis

Mesalamine with MMX Multi Matrix System technology (hereafter referred to as MMX mesalamine) is an oral, high-strength (1.2 g/tablet), once-daily formulation of 5-aminosalicylic acid used for the treatment of ulcerative colitis. This new formulation has been designed to provide delayed and prolonged 5-aminosalicylic acid release throughout the colon. In recent clinical studies, MMX mesalamine (taken as a once-daily dose of 2.4 or 4.8 g) effectively induced clinical remission and mucosal healing versus placebo in patients with active, mild-to-moderate ulcerative colitis. Once remission was achieved, MMX mesalamine effectively maintained disease remission in the majority of patients for at least 12 months. In this paper, we comprehensively review the results of studies exploring the clinical pharmacology, efficacy and safety of MMX mesalamine in patients with ulcerative colitis, and examine the implications of these findings on clinical practice.

Clinical trial: oral prednisolone metasulfobenzoate (Predocol) vs. oral prednisolone for active ulcerative colitis

BACKGROUND

Systemic corticosteroids are effective in ulcerative colitis but commonly cause side effects.

AIM

To compare the safety and efficacy of a sparingly absorbed formulation of prednisolone metasulfobenzoate (Predocol) with a conventional tapering course of oral prednisolone.

METHOD

In a double-blind randomized study, 59 active ulcerative colitis patients received Predocol 40 mg/day for 6 months, 61 received Predocol 60 mg/day for 6 months and 61 received prednisolone 40 mg/day for 2 weeks, tapered to week 8, followed by placebo until 6 months.

RESULTS

Steroid-related side effects assessed using a 10-cm visual analogue scale were fewer at 2 months with Predocol 40 mg [VAS 8.1 cm (2.6), mean (s.d.)], or 60 mg [8.1 (2.1)] compared with prednisolone [6.7 (2.7); P = 0.01]. Mood changes affected 43% receiving prednisolone at 4 weeks vs. 8% for Predocol 40 mg (P = 0.001). Remission rates (Powell-Tuck < or =2) at 2 months were Predocol 40 mg 46%, Predocol 60 mg 28% and tapering prednisolone 41% (P = 0.13). Visual analogue scale for efficacy also showed non-inferiority for Predocol 40 mg/day. Remission rates at 6 months were Predocol 40 mg 51%, Predocol 60 mg 38% and tapering prednisolone 32% (P = 0.08).

CONCLUSION

Predocol 40 mg/day has similar efficacy but markedly fewer side effects than a conventional tapering prednisolone regimen (ISRCTN14133410).

Current treatment of inflammatory bowel disease in children

Children with inflammatory bowel disease present formidable therapeutic challenges. As both Crohn's disease and ulcerative colitis remain medically incurable conditions associated with potentially significant morbidity, the focus of treatment must be to reduce or eliminate symptoms, optimize nutritional status, promote normal growth and development, prevent complications and minimize the potential psychological effects of these chronic illnesses. This review focuses on the evidence supporting the treatments currently used in children with inflammatory bowel disease, and suggests potential treatment algorithms for particular clinical circumstances.

Clinical trial: randomized-controlled clinical study comparing the efficacy and safety of a low-volume vs. a high-volume mesalazine foam in active distal ulcerative colitis

BACKGROUND

Rectally administered mesalazine (mesalamine; 5-aminosalicylic acid) is the first-line therapy for treatment of distal ulcerative colitis. Recently, a high-volume 5-aminosalicylic acid foam has been shown to be as effective and safe as standard 5-aminosalicylic acid enema.

AIM

To study the efficacy and safety of a low-volume vs. a high-volume 5-aminosalicylic acid foam.

METHODS

In this investigator-blinded study, patients with active distal ulcerative colitis [Clinical Activity Index (CAI) > 4, Endoscopic Index > or = 4] were randomized to receive 2 x 1 g/30 mL low-volume (n = 163) or 2 x 1 g/60 mL high-volume 5-aminosalicylic acid foam (n = 167) for 42 days. Primary end point was clinical remission (CAI < or = 4) at the final/withdrawal visit (per-protocol).

RESULTS

330 patients were evaluable for efficacy and safety by intention-to-treat, 290 for per-protocol analysis. Clinical remission rates at week 6 (per-protocol) were 77% on low-volume foam vs. 77% on high-volume foam (P = 0.00002 for non-inferiority). The low-volume foam was associated with a lower frequency of severe discomfort, pain and retention problems.

CONCLUSIONS

Low-volume 5-aminosalicylic acid foam is as effective and safe as a high-volume 5-aminosalicylic acid foam in the treatment of active distal ulcerative colitis, but offers compliance advantages compared to the high-volume preparation.

Current and future therapies for inflammatory bowel disease

The introduction of biologic agents to the therapeutic arsenal has dramatically impacted the way we treat patients with inflammatory bowel disease, allowing clinicians to achieve lasting remission in patients who are unresponsive to conventional therapies. New research continues to expand our understanding of the inflammatory cascade of ulcerative colitis and Crohn's disease, revealing a host of potential therapeutic targets for intervention. As we look toward the future in this rapidly developing field, we must learn how best to incorporate these new agents into the treatment algorithm to enhance or replace conventional therapies.

Molecular cloning, characterisation and ligand-bound structure of an azoreductase from Pseudomonas aeruginosa

The gene PA0785 from Pseudomonas aeruginosa strain PAO1, which is annotated as a probable acyl carrier protein phosphodiesterase (acpD), has been cloned and heterologously overexpressed in Escherichia coli. The purified recombinant enzyme exhibits activity corresponding to that of azoreductase but not acpD. Each recombinant protein molecule has an estimated molecular mass of 23,050 Da and one non-covalently bound FMN as co-factor. This enzyme, now identified as azoreductase 1 from Pseudomonas aeruginosa (paAzoR1), is a flavodoxin-like protein with an apparent molecular mass of 110 kDa as determined by gel-filtration chromatography, indicating that the protein is likely to be tetrameric in solution. The three-dimensional structure of paAzoR1, in complex with the substrate methyl red, was solved at a resolution of 2.18 A by X-ray crystallography. The protein exists as a dimer of dimers in the crystal lattice, with two spatially separated active sites per dimer, and the active site of paAzoR1 was shown to be a well-conserved hydrophobic pocket formed between two monomers. The paAzoR1 enzyme is able to reduce different classes of azo dyes and activate several azo pro-drugs used in the treatment of inflammatory bowel disease (IBD). During azo reduction, FMN serves as a redox centre in the electron-transferring system by mediating the electron transfer from NAD(P)H to the azo substrate. The spectral properties of paAzoR1 demonstrate the hydrophobic interaction between FMN and the active site in the protein. The structure of the ligand-bound protein also highlights the pi-stacking interactions between FMN and the azo substrate.

Efficacy and safety of oral beclomethasone dipropionate for ileal or ileal-right colon Crohn's disease of mild-to-moderate activity or in remission: Retrospective study

Although conventional glucocorticosteroids are the main treatments for active Crohn's disease, several problems are associated with steroid dependence and steroid-related adverse events. To assess the efficacy and safety of oral beclomethasone dipropionate (BDP) coated tablets in adults with mild-to-moderate Crohn's disease. Thirty-four patients (age 18-70years) with a diagnosis of Crohn's disease confirmed by conventional criteria (barium enema, clinical criteria, colonoscopy, histology) were retrospectively evaluated in the study. All subjects received a treatment schedule with BDP 5-10mg/day for 24weeks. BDP significantly (p=0.005) reduced mean Crohn's Disease Activity Index (CDAI) score from 169.6 at baseline to 123.2 after 24weeks. Clinical success was evident at 24weeks in 66.7% of patients with initial active disease, and remission was maintained at week 24 in 93.8% of patients with remission at baseline. Overall, female non-smokers had the best response to treatment. BDP was well tolerated and the only adverse events observed were nausea (n=1), facial erythema (n=1) and one patient with raised fasting blood glucose level. These results clearly suggest that oral BDP coated tablets are effective and safe for treatment of mild-to-moderate Crohn's disease of ileal or ileal-right colonic localisation.

Contemporary morphologic definition of backwash ileitis in ulcerative colitis and features that distinguish it from Crohn disease

Terminal ileum (TI) sections from 250 ulcerative colitis (UC) total colectomy specimens resected during 3 periods and endoscopic TI biopsy specimens from 100 contemporary chronic UC and 100 Crohn disease (CD) patients were reviewed. The respective proportions of cases resected during the 3 periods with moderately or markedly active cecal UC were 72%, 34%, and 2% and with moderate or marked backwash ileitis (BWI), 21%, 18%, and 0%. The activity level of BWI correlated with level of cecal UC. In contemporary initial endoscopic TI biopsy specimens, 6% of chronic UC patients had BWI, all with moderately to markedly active cecal chronic UC. In CD cases, 75% had chronic or active enteritis, consisting of patchy lamina propria edema containing mildly active inflammation, crypt disarray, and focally blunted or flattened villi. Mucous gland metaplasia was present in 27% of CD biopsy specimens. BWI should be restricted to active enteritis that involves the ileum in a contiguous pattern from the cecum that has a similar or greater degree of active inflammation. Mild BWI predominantly involves the superficial mucosa in a contiguous pattern. Focal isolated ileal erosions, mucous gland metaplasia, or patchy edema with mild active inflammation are features of CD.

5-aminosalicylate therapy is associated with higher 6-thioguanine levels in adults and children with inflammatory bowel disease in remission on 6-mercaptopurine or azathioprine

BACKGROUND

Small uncontrolled trials have suggested that 5-aminosalicylate (5-ASA) medications increase 6-thioguanine nucleotide (6-TGn) levels in adults with Crohn's disease (CD) on azathioprine (AZA) or 6-mercaptopurine (6-MP), presumably through the inhibition of thiopurine methyltransferase (TPMT). We tested the theory that coadministration of 5-ASA agents with AZA/6-MP results in higher 6-TGn levels in a large cohort of children and adults with CD or ulcerative colitis (UC).

METHODS

A retrospective cohort study identified all children and adults treated for IBD with AZA/6-MP at 2 tertiary medical centers. Patients were included if their TPMT genotype was known and 6-TGn and 6-methymercaptopurine (6-MMP) levels had been obtained after 3 months of clinical remission at a stable dose of AZA/6-MP. 6-TGn and 6-MMP levels were compared between patients taking and those not taking 5-ASA medications through the use of linear regression models to identify and adjust for potentially confounding variables.

RESULTS

Of the 126 patients included, 88 were taking 5-ASA medications. Patients on 5-ASA agents had higher mean 6-TGn levels after adjustment for confounding variables (Delta6-TGn, 47.6 +/- 21.8 pmol/8 x 10 red blood cells; P = 0.03). CD and TPMT heterozygosity was independently associated with higher 6-TGn levels (P = 0.01 and P = 0.03, respectively). 5-ASA exposure was not associated with a change in 6-MMP levels.

CONCLUSIONS

We found that 5-ASA therapy is associated with higher 6-TGn levels in children and adults with IBD on 6-MP/AZA. TPMT inhibition may not explain this effect because 5-ASA exposure did not affect 6-MMP levels. The observed association of CD with higher 6-TGn levels is novel and needs to be verified in prospective studies.

5-aminosalicylic acid release from a new controlled-release mesalazine formulation during gastrointestinal transit in healthy volunteers

BACKGROUND

Mesalazine (5-aminosalicylic acid, 5-ASA) containing formulations represent a cornerstone in the treatment of inflammatory bowel diseases. A novel formulation with an Eudragit L/S mixture coating has been developed to provide selective release of 5-ASA to the ileo-caecal region and the colon.

AIM

To determine the release of 5-ASA during the gastrointestinal transit.

METHODS

A single oral dose of mesalazine EC 500 mg gastroresistant tablets (Asamax) was administered to eight healthy male volunteers. Gastrointestinal transit and tablet disintegration were monitored by scintigraphy. 5-ASA release was verified by assessing plasma pharmacokinetics.

RESULTS

Initial tablet disintegration was observed 5.65 +/- 0.86 h after dosing, corresponding to the detection of 5-ASA in plasma. This occurred in the ileo-caecal region in three subjects and the ascending colon in the remaining five. The relative percentage of 5-ASA absorption was more pronounced in the ascending colon (41 +/- 27.4%) than the ileo-caecal region (6.6 +/- 9.2%).

CONCLUSION

This mesalazine EC gastroresistant tablets release locally active 5-ASA specifically in the ileo-caecal region and the ascending colon.

Colonic targeting of aminosalicylates for the treatment of ulcerative colitis

Aminosalicylates (5-aminosalicylic acid) represent drugs of first choice in the treatment of ulcerative colitis. Two different therapeutic approaches have been employed to target the active 5-aminosalicylic acid to its site of action. Either inactive azo-prodrugs (e.g. sulfasalazine, olsalazine, balsalazide) or special galenic formulations have been developed for topical delivery of 5-aminosalicylic acid to the colon. However, as intestinal physiology, the extent of ulcerative colitis as well as drug disposition demonstrate large interindividual differences, acute healing rates (40-80%) and the maintenance of remission are quite variable. Apparently, therapeutic effects depend on local concentrations of 5-aminosalicylic acid in the colonic mucosa whereas systemic drug exposure might be one determinant of side effects. In general, 5-aminosalicylic acid is well tolerated and withdrawal from therapy is rare. Following administration of azo-prodrugs (e.g. olsalazine), lower plasma concentrations and higher delivery into the colon of 5-aminosalicylic acid can be observed in comparison to special galenic formulations of 5-aminosalicylic acid. Whether such changes in drug disposition will affect therapeutic efficacy remains to be proved by clinical data. Consequently, selection of a particular agent should be based primarily on clinical efficacy, profile of adverse effects, patients' acceptance and economic considerations.

Oral 5-aminosalicylic acid for maintenance of medically-induced remission in Crohn's Disease

BACKGROUND

Prevention of relapses is a major issue in the management of Crohn's disease. Corticosteroids, the mainstay of treatment of acute exacerbations are not effective in the maintenance of remission and its chronic use is limited by numerous adverse events. A number of randomised controlled trials comparing various 5-ASA agents with either placebo or other drugs have had conflicting results.

OBJECTIVES

To conduct a systematic review to evaluate the efficacy of oral 5-ASA agents for the maintenance of medically-induced remission in Crohn's disease.

SEARCH STRATEGY

We searched MEDLINE (1966 to January 2004), EMBASE (1984-January 2004), the Cochrane Central Register of Controlled Trials from the Cochrane Library (Issue 1, 2004) and the IBD Review Group Specialized Trials Register. We hand-searched the articles cited in each publication.

SELECTION CRITERIA

We included randomised controlled trials which compared oral 5-ASA agents with either placebo or sulphasalazine, with treatment durations of at least 6 months.

DATA COLLECTION AND ANALYSIS

Data extraction and assessment of methodological quality of each study were independently performed by two reviewers. Any disagreement among reviewers was resolved by consensus. The main outcome measure was the occurrence of relapse as defined by the primary studies. Odds ratios of relapse rates and their 95% confidence intervals were calculated.

MAIN RESULTS

5-ASA VERSUS PLACEBO. In the main analysis, we used as the denominator the total number of patients randomised. We assumed that participants who dropped out of the study, and on whom there was no post withdrawal information, had relapsed during the study period. Using the fixed effects model, the odds ratio for 6 studies where participants were followed up for 12 months was 1.00 (95%CI, 0.80 to 1.24). Using the random effects model in a sensitivity analysis had little effect on the results with an OR of 0.93 (95% CI, 0.65 to 1.33). For the seventh study where follow up was for 24 months, the odds ratio was 0.98; 95% CI, 0.51 to 1.90. In further sensitivity analyses, we analysed only participants who completed the study and ignored the dropouts. The odds ratio (fixed effects model) for the 6 studies where follow up was for 12 months was 0.74 (95% CI, 0.57 to 0.96), but using the random effects model, the OR was 0.68 (95% CI 0.45 to 1.02). The OR for the seventh study where follow up was for 24 months (Gendre 1993a), was 0.86; 95% CI, 0.42 to 1.78. 5-ASA VERSUS SULPHASALAZINE. We did not find any study that satisfied the inclusion criteria.

AUTHORS' CONCLUSIONS

We found no evidence in this review to suggest that 5-ASA preparations are superior to placebo for the maintenance of medically-induced remission in patients with Crohn's disease. Therefore it appears that additional randomised trials of this regime are not justified.