Review article: biological agents in the treatment of Crohn's disease

Colon-targeted delivery of live bacterial cell biotherapeutics including microencapsulated live bacterial cells

There has been an ample interest in delivery of therapeutic molecules using live cells. Oral delivery has been stipulated as best way to deliver live cells to humans for therapy. Colon, in particular, is a part of gastrointestinal (GI) tract that has been proposed to be an oral targeted site. The main objective of these oral therapy procedures is to deliver live cells not only to treat diseases like colorectal cancer, inflammatory bowel disease, and other GI tract diseases like intestinal obstruction and gastritis, but also to deliver therapeutic molecules for overall therapy in various diseases such as renal failure, coronary heart disease, hypertension, and others. This review provides a comprehensive summary of recent advancement in colon targeted live bacterial cell biotherapeutics. Current status of bacterial cell therapy, principles of artificial cells and its potentials in oral delivery of live bacterial cell biotherapeutics for clinical applications as well as biotherapeutic future perspectives are also discussed in our review.

Perianal fistulas in Crohn's disease: MRI diagnosis and surgical planning: MRI in fistulazing perianal Crohn's disease

Crohn's disease is a chronic, transmural inflammatory process of the gastrointestinal tract. It often affects the colon with the perianal area. The most common intestinal manifestations include external and/or internal fistulas and abscesses. Assessment of the activity of perianal fistulas in the course of Crohn's disease seems to be an important factor influencing therapeutic approach. Fistula's activity is evaluated by such methods as magnetic resonance imaging, anal ultrasound and examination under anaesthesia. Usefulness of imaging methods in the diagnosis of fistulas still remains to be defined.MRI is used to present a wide spectrum of perianal fistulazing Crohn's disease. Additionally, it is an important instrument revealing location, extent and severity of inflammation. It is also very helpful to detect clinically silent sepsis related to small, local inflammation. The most common method used in MR imaging to assess topography of a fistula's track, is Parks' classification.Clinical indications to MRI may include follow-up studies of a diagnosed disease, classification of fistulas' subtypes in the course of Crohn's disease, determination of the extent of fistulas' tracts and spread of an inflammatory process what can guide surgical procedures.

Role of TNF-alpha in muscularis inflammation and motility disorder in a TNBS-induced colitis model: clues from TNF-alpha-deficient mice

Macroscopic and histological analysis revealed that the colonic inflammation induced by 2,4,6-trinitrobenzenesulphonic acid (TNBS) was of lower grade in tumour necrosis factor-alpha (TNF-alpha)(-/-) mice than in wild-type mice. Myeloperoxidase activity, an indicator of neutrophilic infiltration, was also low in both the mucosal and smooth muscle layer of the TNF-alpha(-/-) mouse colon. After the induction of inflammation with TNBS, the levels of proinflammatory cytokines, such as TNF-alpha, interleukin-1beta and interleukin-6, were elevated both in the inflamed mucosa and muscle layers in the wild-type mice; however, the productions of these cytokines were greatly reduced in the TNF-alpha(-/-) mouse colon. The contractions of isolated colonic smooth muscle strips induced by several stimulatory agents were significantly decreased after treatment with TNBS in wild-type mice; however, these contractions were scarcely affected in TNF-alpha(-/-) mice. Finally, using the organ culture method, we found that TNF-alpha directly (independent of mucosal inflammation) disturbs the smooth muscle function. These results suggest that TNF-alpha plays an essential role not only in mucosal inflammation but also in muscularis inflammation in the colon of mice with TNBS-induced colitis, and that TNF-alpha directly induces motor dysfunctions by acting on the smooth muscle.

Tumor necrosis factor inhibitors: Clinical implications of their different immunogenicity profiles

The beneficial effects of the anti-tumor necrosis factor (TNF) monoclonal antibodies infliximab and adalimumab and the soluble receptor fusion protein etanercept in the treatment of rheumatoid arthritis and a variety of other inflammatory disorders have been well described. However, less is known about the propensity of these agents to stimulate the production of antibodies against themselves and the clinical implications of such immunogenicity. A better understanding of the differential immunogenicity of these agents may help explain certain phenomena that have been reported with clinical use of anti-TNF agents (eg, infusion reactions [all agents], the need for increasing doses with prolonged use [infliximab]). This review will discuss our current understanding of the diverse immunogenic profiles of currently marketed anti-TNF agents.

Enhanced adhesion of ligand‐conjugated biodegradable particles to colitic venules

The expression of certain endothelial cell adhesion molecules (ECAMs) is increased in the vasculature of the inflamed bowel (e.g., colitis), thereby providing an opportunity for targeted drug delivery. We recently demonstrated that biodegradable particles conjugated with ligands to ECAMs exhibit significant selective adhesion to ECAM expressing endothelium. In the present study, we used a murine model of colitis to determine whether poly(lactic acid)-poly(ethylene glycol) particles conjugated with a VCAM-1 ligand (alpha-V) exhibit enhanced adhesion to colitic vasculature. In post-capillary venules of the colon, significantly more alpha-V particles accumulate in colitic mice relative to (i) control mice (i.e., selectivity) and (ii) particles bearing a control ligand (i.e., ligand efficiency). The selectivity and ligand efficiency of alpha-V particles were a function of the total number of particles infused. The highest selectivity observed within our test regime was 3, while ligand efficiency increased linearly with the number of particles injected to a value of 24. This work represents a significant step towards achieving a targeted drug delivery scheme for the treatment of inflammatory bowel disease and indicates that the efficiency of targeting is dependent on the dose regime.

Response, relapse and mucosal immune regulation after infliximab treatment in fistulating Crohn's disease

BACKGROUND

Infliximab reduces mucosal inflammation in some, but not all, patients with Crohn's disease.

AIM

To monitor clinical data and changes in mucosal cytokine levels after infliximab treatment to identify differences between responders and non-responders.

METHODS

Twenty-six patients with fistulating Crohn's disease received three infliximab infusions at weeks 0, 2 and 6. Follow-up was for 1 year and included clinical examination, colonoscopy, ano-rectal ultrasound and magnetic resonance imaging. Biopsies were taken at weeks 0, 8, 26 and 52. Cell cultures were established and analysed for tumour necrosis factor-alpha, interferon-gamma and interleukin-10 levels, and related to clinical status and fistula healing.

RESULTS

Eleven of 15 patients (73%) with active disease (Crohn's disease activity index > 150) obtained remission (Crohn's disease activity index < 150) at 8 weeks. In in vitro cell cultures, there was reduced tumour necrosis factor-alpha and interleukin-10 production at week 26, with the latter persistent throughout the study period. When the disease deteriorated or relapsed, there was increased interferon-gamma production in in vitro cell cultures. Fistula healing was associated with reduced production of interferon-gamma, tumour necrosis factor-alpha and interleukin-10.

CONCLUSIONS

Infliximab down-regulates mucosal immune activation in Crohn's disease. Monitoring of mucosal cytokine levels after infliximab treatment by whole biopsy cultures may be useful as interleukin-10, tumour necrosis factor-alpha and interferon-gamma production are different in responders and at relapse.