New biological therapies in inflammatory bowel disease

Natural Product-Based Nanomedicine in Treatment of Inflammatory Bowel Disease

: Many synthetic drugs and monoclonal antibodies are currently in use to treat Inflammatory Bowel Disease (IBD). However, they all are implicated in causing severe side effects and long-term use results in many complications. Numerous in vitro and in vivo experiments demonstrate that phytochemicals and natural macromolecules from plants and animals reduce IBD-related complications with encouraging results. Additionally, many of them modify enzymatic activity, alleviate oxidative stress, and downregulate pro-inflammatory transcriptional factors and cytokine secretion. Translational significance of natural nanomedicine and strategies to investigate future natural product-based nanomedicine is discussed. Our focus in this review is to summarize the use of phytochemicals and macromolecules encapsulated in nanoparticles for the treatment of IBD and IBD-associated colorectal cancer.

PLGA microspheres encapsulating siRNA anti-TNFalpha: efficient RNAi-mediated treatment of arthritic joints

The aim of this study was to investigate potentialities of poly(dl-lactide-co-glycolide) (PLGA) microspheres for the delivery of small interfering RNAs (siRNAs) against tumor necrosis factor α (TNF-α) to achieve prolonged and efficient inhibition of TNF-α for the treatment of rheumatoid arthritis (RA). PLGA microspheres were prepared by a modified multiple emulsion-solvent evaporation method. The formulations were characterized in terms of morphology, mean diameter and siRNAs distribution, encapsulation efficiency, and in vitro release kinetics. The efficiency of this system was then evaluated both in vitro and in vivo using the murine monocytic cell line J774 and a pre-clinical model of RA, respectively. siRNA-encapsulating PLGA microspheres were characterized by a high encapsulation efficiency and a slow and prolonged anti-TNF-α siRNAs. Our results provide evidence that, upon intra-articular administration, PLGA microspheres slowly releasing siRNAs effectively inhibited the expression of TNF-α in arthritic joints. Our system might represent an alternative strategy for the design of novel anti-rheumatic therapies based on the use of RNA interference in RA.

Potential prospects of nanomedicine for targeted therapeutics in inflammatory bowel diseases

Inflammatory bowel diseases (IBDs) such as Crohn’s disease are highly debilitating. There are inconsistencies in response to and side effects in the current conventional medications, failures in adequate drug delivery, and the lack of therapeutics to offer complete remission in the presently available treatments of IBD. This suggests the need to explore beyond the horizons of conventional approaches in IBD therapeutics. This review examines the arena of the evolving IBD nanomedicine, studied so far in animal and in vitro models, before comprehensive clinical testing in humans. The investigations carried out so far in IBD models have provided substantial evidence of the nanotherapeutic approach as having the potential to overcome some of the current drawbacks to conventional IBD therapy. We analyze the pros and cons of nanotechnology in IBD therapies studied in different models, aimed at different targets and mechanisms of IBD pathogenesis, in an attempt to predict its possible impact in humans.

Dual TNF-α/Cyclin D1 Gene Silencing With an Oral Polymeric Microparticle System as a Novel Strategy for the Treatment of Inflammatory Bowel Disease

OBJECTIVES:

RNA silencing utilizing short interfering RNA (siRNA) offers a new and exciting means to overcome the limitations of current treatment options of many diseases. However, delivery of these molecules still poses a great challenge to date.

METHODS:

In the present study, a multicompartmental biodegradable polymer-based nanoparticles-in-microsphere oral system (NiMOS) using gelatin nanoparticles encapsulating a combination of siRNA duplexes specifically targeted against tumor necrosis factor-α (TNF-α) and cyclin D1 (Ccnd1) was employed to study its effects on a dextran sulfate sodium (DSS)-induced acute colitis mouse model mimicking inflammatory bowel disease (IBD). DSS colitis-bearing animals were divided into several control and treatment groups and received either no treatment, blank NiMOS, NiMOS-encapsulating inactive (scrambled), active TNF-α silencing, CyD1 silencing siRNA, or a combination of both active siRNAs by repeated oral administration of three NiMOS doses.

RESULTS:

Successful gene silencing with the aid of dual siRNA treatment led to decreased colonic levels of TNF-α or CyD1, suppressed expression of certain pro-inflammatory cytokines (interleukin-1α and -β, interferon-γ), an increase in body weight, and reduced tissue myeloperoxidase activity, while the silencing effect of CyD1 siRNA or the dual treatment was more potent than that of TNF-α siRNA alone.

CONCLUSION:

Results of this study demonstrate the therapeutic potential of a NiMOS-based oral combined TNF-α and CyD1 gene silencing system for the treatment of IBD as shown in an acute colitis model.

Oral TNF-α gene silencing using a polymeric microsphere-based delivery system for the treatment of inflammatory bowel disease

The purpose of this study was to evaluate down-regulation of tumor necrosis factor (TNF)-α by oral RNA interference therapy. Control (scrambled sequence) or TNF-α specific small interfering RNA (siRNA) was encapsulated in type B gelatin nanoparticles and further entrapped in poly(epsilon-caprolactone) (PCL) microspheres to form a nanoparticles-in-microsphere oral system (NiMOS). Upon confirmation of the dextran sulfate sodium (DSS)-induced acute colitis model, mice were divided into several treatment groups receiving no treatment, blank NiMOS, NiMOS with scramble siRNA, or NiMOS with TNF-α silencing siRNA by oral administration. Successful gene silencing led to decreased colonic levels of TNF-α, suppressed expression of other pro-inflammatory cytokines (e.g., interleukin (IL)-1β, interferon (IFN)-γ) and chemokines (MCP-1), an increase in body weight, and reduced tissue myeloperoxidase activity. Results of this study established the clinical potential of a NiMOS-based oral TNF-α gene silencing system for the treatment of inflammatory bowel disease as demonstrated in an acute colitis model.

Tetomilast suppressed production of proinflammatory cytokines from human monocytes and ameliorated chronic colitis in IL-10-deficient mice

BACKGROUND

Tetomilast (OPC-6535) was originally developed as a compound inhibiting superoxide production in neutrophils. Although its mechanism of action is not completely understood, phosphodiesterase type 4 inhibitory function has been postulated. The therapeutic effect of PDE4 inhibitors has been reported for chronic inflammatory disorders such as chronic obstructive pulmonary diseases. In this study we aimed to examine whether tetomilast could be a novel drug for inflammatory bowel diseases by further clarifying its antiinflammatory effects.

METHODS

Cytokines from human peripheral blood mononuclear cells were measured by enzyme-linked immunosorbent assay (ELISA) and Cytokine Beads Array. The transcripts were quantified by reverse-transcriptase polymerase chain reaction (RT-PCR). Phosphorylation of transcription factors was examined by phosflow. To examine its in vivo effect, a once-daily oral dose of tetomilast was tested in murine IL-10(-/-) chronic colitis.

RESULTS

Tetomilast suppressed TNF-alpha and IL-12 but not IL-10 production from lipopolysaccharide (LPS)-stimulated human monocytes. It suppressed TNF-alpha, IFN-gamma, and IL-10 from CD4 lymphocytes. Tetomilast suppressed cytokine production at the transcriptional level but did not alter phosphorylation of p65, ERK, p38, and STAT3. HT-89, a protein kinase A inhibitor, did not abolish the effect of tetomilast, suggesting that it was independent from the classical cAMP/PKA pathway. IL-10 was not essential to the inhibitory effect of tetomilast on TNF-alpha and IL-12. Tetomilast ameliorated IL-10(-/-) chronic colitis with reduced clinical symptoms, serum amyloid A, and histological scores with decreased TNF-alpha mRNA expression.

CONCLUSIONS

Tetomilast exerts its antiinflammatory effects on human monocytes and CD4 cells. Combined with in vivo data these findings support the feasibility of tetomilast as a novel drug for inflammatory bowel diseases.

Modulation of cytokine secretion by pentacyclic triterpenes from olive pomace oil in human mononuclear cells

Olive pomace oil, also known as "orujo" olive oil, is a blend of refined-pomace oil and virgin olive oil, fit for human consumption. Maslinic acid, oleanolic acid, erythrodiol, and uvaol are pentacyclic triterpenes, found in the non-glyceride fraction of orujo oil, which have previously been reported to have anti-inflammatory properties. In the present work, we investigated the effect of these minor components on pro-inflammatory cytokine production by human peripheral blood mononuclear cells in six different samples. Uvaol, erythrodiol, and oleanolic acid significantly decreased IL-1beta and IL-6 production in a dose-dependent manner. All three compounds significantly reduced TNF-alpha production at 100microM; however, at 10microM, uvaol and oleanolic acid enhanced the generation of TNF-alpha. In contrast, maslinic acid did not significantly alter the concentration of those cytokines, with the exception of a slight inhibitory effect at 100microM. All four triterpenes inhibited production of I-309, at 50microM and 100microM. However, uvaol enhanced I-309 production at 10microM. The triterpenic dialcohols had a similar effect on MIG production. In conclusion, this study demonstrates that pentacyclic triterpenes in orujo oil exhibit pro- and anti-inflammatory properties depending on chemical structure and dose, and may be useful in modulating the immune response.

Infliximab for juvenile idiopathic arthritis-associated uveitis

BACKGROUND

Infliximab is a murine-human recombinant antitumour necrosis factor monoclonal antibody recently introduced for the treatment of autoimmune diseases in which tumour necrosis factor is thought to be a key mediator. Its role in the treatment of juvenile idiopathic arthritis-associated uveitis is as yet undefined.

METHODS

Six children with juvenile idiopathic arthritis-associated uveitis, inadequately controlled on currently available therapy, were treated with infliximab between September 2002 and November 2004. All children were required to remain on low-dose immunomodulatory treatment in conjunction with the infliximab. A retrospective review of two electronic databases containing details of ophthalmology and rheumatology visits was conducted.

RESULTS

In all six children, institution of infliximab therapy was associated with increased ease of management. Ocular inflammation and intraocular pressure control improved in all. It was also possible to reduce the dose or withdraw some glaucoma, steroid and other immunomodulatory drugs. Two children underwent intraocular surgery without noticeable flare of intraocular inflammation. No patient developed any serious systemic complications attributable to infliximab.

CONCLUSION

Infliximab may be a useful adjunct to the management of refractory juvenile idiopathic arthritis-associated uveitis. In our series it was associated with improved uveitis control and simplification of drug use as well as possibly improving safety of surgical intervention. This study suggests that its role is likely to be in conjunction with maintenance immunomodulatory treatment to provide more optimal disease control. Controlled studies are required to confirm its efficacy and safety, and the potential breadth of its use in uveitis and related disorders.

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.

Intravenous CDP870, a PEGylated Fab' fragment of a humanized antitumour necrosis factor antibody, in patients with moderate-to-severe Crohn's disease: an exploratory study

BACKGROUND

CDP870 is a PEGylated Fab' fragment of a humanized monoclonal antibody that neutralizes tumour necrosis factor-alpha.

AIM

To evaluate the safety and efficacy of a single intravenous dose of CDP870 or placebo over a 12-week period in patients with moderate-to-severe Crohn's disease.

METHODS

Ninety-two adult patients with Crohn's disease (Crohn's Disease Activity Index: 220-450 points) were randomized to receive CDP870 [1.25 (n = 2), 5 (n =26), 10 (n = 17) or 20 mg/kg (n = 23)] or placebo (n = 24). Crohn's Disease Activity Index scores were determined at weeks 0, 2, 4, 8 and 12. The primary end-point was the percentage of patients achieving clinical response [i.e. a decrease in Crohn's Disease Activity Index score > or = 100 points or remission (Crohn's Disease Activity Index score: < or =150 points)] at week 4 in the intent-to-treat population.

RESULTS

The percentage of patients achieving the primary end-point was comparable across all treatment groups (56.0%, 60.0%, 58.8% and 47.8% for placebo, CDP870 5, 10 and 20 mg/kg, respectively). The remission rate at week 2 was 47.1% with CDP870 10 mg/kg vs. 16.0% for placebo (P = 0.041). All treatments were well-tolerated: adverse events, reported by 43 patients treated with CDP870 and 15 patients treated with placebo, were mainly mild-to-moderate in intensity. There were no infusion reactions.

CONCLUSIONS

A single intravenous dose of CDP870 was well-tolerated by patients with Crohn's disease. While no statistically significant difference in clinical response rates between CDP870 and placebo was observed, clinical benefit in terms of remission was demonstrated.

Celastrol inhibits pro-inflammatory cytokine secretion in Crohn's disease biopsies

Crohn's disease is a chronic intestinal inflammatory process. In modern therapy, TNF-alpha inhibition is the main goal. The aim here is to characterize the effects of Celastrol, a pentacyclic-triterpene, on the secretion of inflammatory cytokines by LPS-activated human cells. Celastrol dose-dependently inhibited the secretion of all tested pro-inflammatory cytokines with IC(50) in the nanomolar range. Effect not related to glucocorticoid receptor activity is shown by competition experiments with the steroid antagonist RU486. Celastrol inhibited the pro-inflammatory cytokine secretion from mucosal inflammatory biopsies from Crohn's disease patients. Cytometry emphasized that for all tested pro-inflammatory cytokines, CD33(+) cells are the most sensitive. Quantitative-PCR and confocal analysis on a human monocytic cell line indicated that Celastrol acts at the transcriptional level by inhibiting LPS-induced NF-kappaB translocation. Celastrol might be a putative anti-inflammatory drug in the treatment of inflammatory diseases, given its inhibition of cytokine production by intestinal biopsies from Crohn's disease patients.

Novel biologics in inflammatory bowel disease

Understanding of immunologic mechanisms involved in the initiation and perpetuation of chronic inflammation has led to new therapeutic opportunities in the inflammatory bowel diseases. The term "biologics" is used to distinguish new biotechnologic therapeutics from the conventional drugs used in the treatment of immune-mediated inflammatory disorders. This article reviews novel biologic therapies that are being investigated for the treatment of Crohn's disease and ulcerative colitis.

Infliximab heals intestinal inflammatory lesions and restores growth in children with Crohn's disease

BACKGROUND

Infliximab has recently emerged as an efficacious agent for patients with severe Crohn's disease. There are only few studies on the use of infliximab in children with Crohn's disease: most of them are retrospective and deal only with the clinical response to the drug.

AIM

We aimed at assessing the efficacy of infliximab in children and adolescents with severe Crohn's disease recruited consecutively and followed up prospectively at a single centre. Clinical response, intestinal inflammation and growth pattern were evaluated.

PATIENTS

Eighteen patients entered into the trial (median age: 13 years, range: 6-18). They were referred because of severe symptoms with unsatisfactory response to conventional drugs.

METHODS

All patients received a baseline schedule of three intravenous infusions of infliximab (0, 2 and 6 weeks), 5 mg/kg. Paediatric Crohn's Disease Activity Index, nutritional and activity serum variables, and ileocolonoscopy (with histology) were evaluated before and 8 weeks after beginning the therapy. All patients had long-term administration of azathioprine (2 mg/kg per day). After the baseline schedule, eight patients had a retreatment infusion of infliximab (5 mg/kg) every 8 weeks. Weight and height Z scores were measured before starting the baseline infusion programme and after 6 months.

RESULTS

After 8 weeks of therapy, there was a dramatic improvement in Paediatric Crohn's Disease Activity Index, in nutritional and activity blood parameters, as well as in endoscopic and histological scores; 10 patients had a clinical remission (Paediatric Crohn's Disease Activity Index < or = 10), 12 patients had an inflammatory remission (decrease in both endoscopic and histological scores for > or = 50% as compared to baseline values). In all patients corticosteroids were stopped within 4 weeks after beginning infliximab therapy. After 6 months of therapy, Paediatric Crohn's Disease Activity Index was markedly lower than the pre-treatment value; however, it was significantly lower in patients on retreatment than in those who received only three infusions of infliximab. Furthermore, a significant increase in both weight and height Z scores was observed 6 months after beginning of the baseline infusion programme. Moreover, weight and height gain was significantly higher in patients on retreatment rather than in those treated only with three baseline infusions of infliximab. Mild infusion reactions controlled by slowing infusion rate were observed in four patients. No delayed hypersensitivity-like reactions were seen.

CONCLUSIONS

In children with severe Crohn's disease, infliximab is a safe and valuable treatment in inducing remission, in healing inflammatory lesions of the gut, as documented by endoscopy and histology, and in promoting growth. Retreatment infusions of infliximab may be suggested in childhood-onset Crohn's disease to maintain remission and reverse growth failure.