Recent developments in the pharmacological treatment of Crohn’s disease

Novel Magnetic Nanostructured Beads for Cadmium(II) Removal

This study presents an effective magnetic separation method for cadmium removal, based on the use of a novel nanostructured material as an adsorbent. This adsorbent involves the incorporation of magnetite nanoparticles (Fe₃O₄-NPs), synthesized by the reverse coprecipitation method, into sodium alginate and activated carbon to form spherical structures by crosslinking Ca2+ ions with the charged alginate chains, referred to as magnetic alginate activated carbon (MAAC) beads. The effect of the experimental parameters, such as pH, contacting time, adsorbent dosage, agitation type, and rotating speed were investigated and optimized for an efficient removal of Cd(II) ions at an initial concentration of 250 mg/L. The amount of adsorbed Cd(II) by MAAC beads increased at a pH of 6 with a removal efficiency over 90%. The maximum adsorption capacity reached was 70 mg/g of adsorbent at an initial Cd(II) concentration of 150 mg/L, whereas at 250 mg/L the adsorption capacity lowered until 60 mg/g. Sorption isotherms were calculated using Langmuir, Freundlich, Temkin, and Dubinin⁻Radushkevich equations, and were better described by the Freundlich and Temkin models. These results proved the removal efficiency and the potential use under real environmental conditions of the MAAC beads, due to their easy recovery from contaminated aqueous solutions.

Novel Therapies for Crohn's Disease: Focus on Immunomodulators and Antibiotics

Objective:

To review the literature on novel immunomodulators such as tumor necrosis factor alpha (TNF-α)- and interleukin (IL)-related agents, 6-thioguanine (6-TG), tacrolimus, and leflunomide, and antibiotics such as ornidazole, rifaximin, and ciprofloxacin for the treatment of Crohn's disease.

Data Sources:

Literature was accessed through MEDLINE (1966–January 2006) using the terms Crohn's disease, novel therapies, immunomodulators, and antibiotics. Article references were hand-searched for additional relevant articles and abstracts.

Study Selection and Data Extraction:

All articles in English identified from the data sources were evaluated. Studies including greater than 5 patients with primarly adult populations were included in the review.

Data Synthesis:

There are a number of new TNF-α and IL-related agents that may be useful for management of Crohn's disease. They include CDP 571, CDP 870, etanercept, onercept, thalidomide, IL-10, and IL-11. Several studies have shown that CDP 571 decreases the Crohn's Disease Activity Index score and is promising, especially in patients with refractory disease. 6-TG, tacrolimus, and leflunomide are among other immunomodulators that appear to have a role in refractory/severe disease. Finally, ornidazole, rifaximin, and ciprofloxacin are antimicrobials that may be used in patients who have failed other therapies or as adjunctive therapies.

Conclusions:

A number of new treatment modalities are being investigated for Crohn's disease. Many of them are promising, and some of these agents may be considered in treatment-refractory patients in the future. However, some of the agents reviewed here are not available in the US. Future studies need to be double-blinded and placebo- or other treatment-controlled in a more homogeneous patient population.

XRD, vibrational spectra and quantum chemical studies of an anticancer drug: 6-Mercaptopurine

The single crystal of the hydrated anticancer drug, 6-Mercaptopurine (6-MP), has been grown by slow evaporation technique under room temperature. The structure was determined by single crystal X-ray diffraction. The vibrational spectral analysis was carried out using Laser Raman and FT-IR spectroscopy in the range of 3300-100 and 4000-400 cm(-1). The single crystal X-ray studies shows that the crystal packing is dominated by N-H⋯O and O-H⋯N classical hydrogen bonds leading to a hydrogen bonded ensemble. This classical hydrogen bonds were further connected through O-H⋯S hydrogen bond to form two primary ring R4(4)(16) and R4(4)(12) motifs. These two primary ring motifs are interlinked with each other to build a ladder like structure. These ladders are connected through N-H⋯N hydrogen bond along c-axis of the unit cell through chain C(5) motifs. Further, the strength of the hydrogen bonds is studied through vibrational spectral measurements. The shifting of bands due to the intermolecular interactions was also analyzed in the solid crystalline state. Geometrical optimizations of the drug molecule were done by Density Functional Theory (DFT) using the B3LYP function and Hartree-Fock (HF) level with 6-311++G(d,p) basis set. The optimized molecular geometry and computed vibrational spectra are compared with experimental results which show significant agreement. The natural bond orbital (NBO) analysis was carried out to interpret hyperconjugative interaction and intramolecular charge transfer (ICT). The chemical hardness, electro-negativity and chemical potential of the molecule are carried out by HOMO-LUMO plot. In which, the frontier orbitals has lower band gap value indicating the possible pharmaceutical activity of the molecule.

Wormwood (Artemisia absinthium) suppresses tumour necrosis factor alpha and accelerates healing in patients with Crohn's disease - A controlled clinical trial

Suppression of tumour necrosis factor alpha (TNF-alpha) and other interleukins by wormwood (Artemisia absinthium) extracts were reported recently in in vitro studies. The aim of the present study was to find out if this effect can be also be observed in Crohn's Disease (CD) patients where TNF-alpha appears to play an important role. In a controlled trial, 10 randomly selected patients suffering from CD were given in addition to their basic CD therapy 3x750mg dried powdered wormwood for 6 weeks. Ten patients, also randomly selected who met the inclusion criteria served as control group. Minimum score of 200 on Crohn's Disease Activity Index (CDAI) was required at baseline for inclusion in each group. Patients who received infliximab or similar were excluded from the trial. TNF-alpha level in serum were measured at baseline, and after three and six weeks. During this period all concomitant CD medications was maintained at the baseline dose levels. Average serum TNF-alpha level fell from 24.5+/-3.5pg/ml at baseline to 8.0+/-2.5pg/ml after six weeks. The corresponding levels in the control group were 25.7+/-4.6 (week 0), and 21.1+/-3.2 (week 6). On the clinical side, CDAI scores fell from 275+/-15 to below 175+/-12 in wormwood group with remission of symptoms in eight patients (CDAI score below 170 or reduction by 70 points), compared to only two in the placebo group (CDAI of placebo group 282+/-11 at baseline and 230+/-14 on week 6). IBDQ also reflected accelerated clinical response with wormwood. Of clinical significance were the findings that wormwood also improved mood of the CD patients, as reflected in Hamilton's Depression Scale. These findings provide a base to test wormwood in clinical conditions thought to be mediated by increased production of pro-inflammatory cytokines such as TNF-alpha.

Protection against dextran sodium sulfate-induced colitis by dehydroepiandrosterone and 7alpha-hydroxy-dehydroepiandrosterone in the rat

In this study the anti-oxidant effect of DHEA and 7alpha-hydroxy-DHEA against oxidative stress induced by colitis was investigated in vivo in rats. The two steroids were intraperitoneally injected once daily (50 mg/kg body weight) for 7 days before the induction of colitis that was effected by a daily treatment of 5% (w/v) dextran sodium sulfate (DSS) in drinking water for 7 days. This was quantified by the evidence of weight loss, rectal bleeding, increased wall thickness, and colon length. The inflammatory response was assessed by neutrophil infiltration after a histological examination and myeloperoxidase (MPO) activity measurement. Two markers of oxidative damage were measured in colon homogenates after the onset of DSS treatment: protein carbonyls and thiobarbituric acid-reacting substances. The colonic metabolism of corticosterone by 11beta-hydroxysteroid dehydrogenases types 1 and 2 (11beta-HSD) was investigated in control and treated animals. Results indicated that colitis caused a decrease in body weight and colon length. Severe lesions were observed in the colon with a reduced number of goblet cells which contained less mucins. The lesions were associated with increased MPO activity and oxidative damage. Colonic inflammation down and up regulated the 11beta-HSD2 and 11beta-HSD1, respectively. Treatments by DHEA and 7alpha-hydroxy-DHEA attenuated the inflammatory response when MPO activity decreased; but this did not increase the colonic oxidation of corticosterone into 11-dehydrocorticosterone. Both DHEA and 7alpha-hydroxy-DHEA exerted a significant anti-oxidant effect against oxidative stress induced by colitis through reducing the oxidative damage to proteins and lipids. This resulted in a moderate increase in the amount of colonic mucus. Both DHEA and 7alpha-hydroxy-DHEA may prove useful in the prevention or treatment of colitis.

Advances in gastrointestinal pharmacotherapy

The medical management of patients with gastrointestinal diseases is advancing rapidly. At a recent symposium held during Digestive Disease Week in Chicago in May of 2005, specific attention was given to the future prospects for medical management of 3 common gastrointestinal disease areas: antisecretory therapy, chronic hepatitis C, and inflammatory bowel disease. Antisecretory approaches include drug combinations including a proton pump inhibitor, potassium competitive acid blockers, and antigastrin agents. The latter two classes are still experimental, but the former combinations have potential to enhance the highly effective agents currently available. The focus of treatment advances in chronic hepatitis C in the immediate future is the discovery of more effective treatment regimens for nonresponders to prior therapy, who are becoming the largest group of patients seeking treatment of hepatitis C. The combination of peginterferon with ribavirin results in 6%-15% sustained virologic response rates in patients who were prior nonresponders to standard interferon plus ribavirin. Newer strategies to eradicate hepatitis C virus infection using different interferons, such as interferon alfacon-1 or higher doses of peginterferon, or long-term maintenance peginterferon, are undergoing study and show promise based on data from preliminary studies. Several immunomodulators have promise in inflammatory bowel disease, although the risk-benefit ratio and costs of therapy require evaluation. Nevertheless, the success of new biologics such as anti-TNFalpha agents augurs well for effective future therapies.

Disruption of the interaction of T cells with antigen-presenting cells by the active leflunomide metabolite teriflunomide: involvement of impaired integrin activation and immunologic synapse formation

OBJECTIVE

Leflunomide, a potent disease-modifying antirheumatic drug of the isoxazole class, exhibits antiinflammatory, antiproliferative, and immunosuppressive effects by largely unknown mechanisms, although alterations of pyrimidine synthesis have been proposed. Successful immune responsiveness requires T cell activation by interaction with antigen-presenting cells (APCs), and integrin activation and formation of an immunologic synapse (IS). In this study, we evaluated the impact of the active leflunomide metabolite teriflunomide on T cell integrin activation, evolution of the IS, and antigen-specific formation of stable T cell/APC conjugates.

METHODS

Effects of pharmacologic concentrations of teriflunomide on CD3/CD28- and lymphocyte function-associated antigen 1-induced signal transduction and activation of primary human T cells were investigated. Furthermore, T cells were stimulated with superantigen- and antigen-pulsed APCs to study relocalization of molecules to the IS and T cell/APC conjugate formation.

RESULTS

Teriflunomide inhibited T cell receptor (TCR)/CD3-mediated calcium mobilization, but other critical T cell signaling events, including activation of MAPK and NF-kappaB, remained unaltered. In contrast, inhibition of TCR/CD3-triggered beta1,2 integrin avidity and integrin-mediated costimulation (outside-in signaling) by teriflunomide revealed a striking interference with integrin function that was independent of altered pyrimidine synthesis. Moreover, teriflunomide abolished molecule relocalization to the IS and induction of T cell/APC conjugates.

CONCLUSION

These data show that the active metabolite of leflunomide prevents the interaction of T cells with APCs to form an IS. Since IS formation is crucial for eliciting an immune response, this novel mechanism could underlie the beneficial effects of leflunomide in immune-mediated disorders such as rheumatoid arthritis.

Traveller's diarrhoea

Traveller's diarrhoea affects over 50% of travellers to some destinations and can disrupt holidays and business trips. This review examines the main causes and epidemiology of the syndrome, which is associated with poor public health infrastructure and hygiene practices, particularly in warmer climates. Although travellers may be given common sense advice on avoidance of high-risk foods and other measures to prevent traveller's diarrhoea, adherence to such advice is sometimes difficult and the evidence for its effectiveness is contradictory. However, non-antimicrobial means for prevention of traveller's diarrhoea are favoured in most settings. A simple stepwise approach to the management of traveller's diarrhoea includes single doses or 3-day courses of antimicrobials, often self administered. The antibiotics of choice are currently fluoroquinolones or azithromycin, with an emerging role for rifaximin. In the long term, there will be greater benefit and effect on the health of local inhabitants and travellers from improving public health and hygiene standards at tourist destinations.