Safety of biologics in inflammatory bowel disease

Caffeic acid phenethyl ester is protective in experimental ulcerative colitis via reduction in levels of pro-inflammatory mediators and enhancement of epithelial barrier function

Background

Inhibition of the nuclear factor kappa beta (NF-κβ) pathway has been proposed as a therapeutic target due to its key role in the expression of pro-inflammatory genes, including pro-inflammatory cytokines, chemokines, and adhesion molecules. Caffeic acid phenethyl ester (CAPE) is a naturally occurring anti-inflammatory agent, found in propolis, and has been reported as a specific inhibitor of NF-κβ. However, the impact of CAPE on levels of myeloperoxidases (MPO) and pro-inflammatory cytokines during inflammation is not clear. The aims of this study were to investigate the protective efficacy of CAPE in the mouse model of colitis and determine its effect on MPO activity, pro-inflammatory cytokines levels, and intestinal permeability.

Method

Dextran sulphate sodium was administered in drinking water to induce colitis in C57/BL6 mice before treatment with intraperitoneal administration of CAPE (30 mg kg⁻¹ day⁻¹). Disease activity index (DAI) score, colon length and tissue histology levels of MPO, pro-inflammatory cytokines, and intestinal permeability were observed.

Results

CAPE-treated mice had lower DAI and tissue inflammation scores, with improved epithelial barrier protection and significant reduction in the level of MPO and pro-inflammatory cytokines.

Conclusion

Our results show that CAPE is effective in suppressing inflammation-triggered MPO activity and pro-inflammatory cytokines production while enhancing epithelial barrier function in experimental colitis. Thus, we conclude that CAPE could be a potential therapeutic agent for further clinical investigations for treatment of inflammatory bowel diseases in humans.

Electronic supplementary material

The online version of this article (doi:10.1007/s10787-017-0364-x) contains supplementary material, which is available to authorized users.

Nox1 causes ileocolitis in mice deficient in glutathione peroxidase-1 and -2

We previously reported that mice deficient in two Se-dependent glutathione peroxidases, GPx1 and GPx2, have spontaneous ileocolitis. Disease severity depends on mouse genetic background. Whereas C57BL/6J (B6) GPx1/2-double-knockout (DKO) mice have moderate ileitis and mild colitis, 129S1Svlm/J (129) DKO mice have severe ileocolitis. Because GPx's are antioxidant enzymes, we hypothesized that elevated reactive oxygen species trigger inflammation in these DKO mice. To test whether NADPH oxidase 1 (Nox1) contributes to colitis, we generated B6 triple-KO (TKO) mice to study their phenotype. Because the Nox1 gene is X-linked, we analyzed the effects of Nox1 on male B6 TKO mice and female B6 DKO mice with the Nox1(+/-) (het-TKO) genotype. We found that the male TKO and female het-TKO mice are virtually disease-free when monitored from 8 through 50 days of age. Male TKO and female het-TKO mice have nearly no signs of disease (e.g., lethargy and perianal alopecia) that are often exhibited in the DKO mice; further, the slower growth rate of DKO mice is almost completely eliminated in male TKO and female het-TKO mice. Male TKO and female het-TKO mice no longer have the shortened small intestine present in the DKO mice. Finally, the pathological characteristics of the DKO ileum, including the high level of crypt apoptosis (analyzed by apoptotic figures, TUNEL, and cleaved caspase-3 immunohistochemical staining), high numbers of Ki-67-positive crypt epithelium cells, and elevated levels of monocytes expressing myeloperoxidase, are all significantly decreased in male TKO mice. The attenuated ileal and colonic pathology is also evident in female het-DKO mice. Furthermore, the male DKO ileum has eightfold higher TNF cytokine levels than TKO ileum. Nox1 mRNA is highly elevated in both B6 and 129 DKO ileum compared to wild-type mouse ileum. Taking these results together, we propose that ileocolitis in the DKO mice is caused by Nox1, which is induced by TNF. The milder disease in female het-TKO intestine is probably due to random or imprinted X-chromosome inactivation, which produces mosaic Nox1 expression.

Sensitivity-related illness: the escalating pandemic of allergy, food intolerance and chemical sensitivity

The prevalence of allergic-related diseases, food intolerance, and chemical sensitivities in both the pediatric and adult population has increased dramatically over the last two decades, with escalating rates of associated morbidity. Conditions of acquired allergy, food intolerance and chemical hypersensitivity are frequently the direct sequelae of a toxicant induced loss of tolerance (TILT) in response to a significant initiating toxic exposure. Following the primary toxicant insult, the individuals become sensitive to low levels of diverse and unrelated triggers in their environment such as commonly encountered chemical, inhalant or food antigens. Among sensitized individuals, exposure to assorted inciting stimuli may precipitate diverse clinical and/or immune sequelae as may be evidenced by clinical symptoms as well as varied lymphocyte, antibody, or cytokine responses in some cases. Recently recognized as a mechanism of disease development, TILT and resultant sensitivity-related illness (SRI) may involve various organ systems and evoke wide-ranging physical or neuropsychological manifestations. With escalating rates of toxicant exposure and bioaccumulation in the population-at-large, an increasing proportion of contemporary illness is the direct result of TILT and ensuing SRI. Avoidance of triggers will preclude symptoms, and desensitization immunotherapy or immune suppression may ameliorate symptomatology in some cases. Resolution of SRI generally occurs on a gradual basis following the elimination of bioaccumulated toxicity and avoidance of further initiating adverse environmental exposures. As has usually been the case throughout medical history whenever new evidence regarding disease mechanisms emerges, resistance to the translation of knowledge abounds.

Durability of infliximab in Crohn's disease: a single-center experience

BACKGROUND

Infliximab is effective maintenance for moderate to severe Crohn's disease (CD); however, problems with immunogenicity and decreased efficacy often complicate long-term use. Durability of infliximab maintenance therapy over multiple years has not been defined.

METHODS

This was a retrospective, observational study of CD patients who received maintenance infliximab for ≥1 year with the intention of ongoing maintenance. Patients were categorized into those who either discontinued treatment or continued maintenance therapy. We examined the impact of demographic, clinical characteristics, and prior episodic exposure on long-term durability of infliximab therapy and also examined the reasons for discontinuation of therapy.

RESULTS

A total of 153 CD patients received maintenance infliximab treatment beyond 1 year and 42 (27%) ultimately discontinued treatment. The mean duration of maintenance treatment at the time of discontinuation was 42.4 ± 19.1 months compared to a follow-up period of 49.4 ± 19.8 months in the cohort continuing therapy (P = 0.049). The main reasons for discontinuation were allergy/adverse reaction (44.2%) and decreased efficacy (38.2%). Use of concomitant immunosuppression was similar between the 2 groups (78.6% versus 83.8%, P = NS). However, the discontinued group had a higher rate of prior episodic dosing compared to CD patients who continued maintenance (28.8% versus 11.7%, P = 0.025), while there was no difference in the rate of intensified dosing (57.2% versus 50.5%, P = NS).

CONCLUSIONS

One-quarter of CD patients on long-term infliximab maintenance discontinued treatment. A history of prior episodic dosing was significantly associated with infliximab discontinuation, despite concomitant immunosuppression. These data emphasize the need for optimization of infliximab for successful long-term management.

The role of anti-tumor necrosis factor-alpha therapy in Pyoderma gangrenosum associated with inflammatory bowel disease

Pyoderma gangrenosum (PG) is an ulcerative neutrophilic dermatosis seen in 1-5% of patients with inflammatory bowel disease (IBD). The pathogenesis of PG remains unclear, but may be related to abnormal T-cell responses and production of tumor necrosis factor (TNF)-alpha, a powerful proinflammatory cytokine. Although their use is not supported by appropriately controlled trials, corticosteroids and systemic immunosuppressants are the classical cornerstones of treatment of PG, against which they have a nonspecific effect. Successful curative or symptomatic treatment of associated disorders may lead to an improvement in PG. A new era for the management of chronic inflammatory disease began with the advent of biotherapies and particularly anti-TNFalpha therapy, which allows for a specific intervention in the immune cascade. Anti-TNFalpha therapy has improved and broadened the therapeutic options for IBD and, therefore, has brought new perspectives to management of the extra-intestinal manifestations of this disorder, including PG. To date, infliximab, etanercept, and adalimumab have been used in the treatment of PG. Published data have demonstrated that infliximab is highly effective in the treatment of PG, whether associated with IBD or not. This treatment is generally well tolerated, even as long-term therapy. However, rare and serious complications have been reported. Although infliximab is a costly drug, its use should be considered for patients with PG and particularly with corticosteroid-refractory PG associated with IBD. Additional comparative long-term studies are needed to determine the long-term efficacy and safety of anti-TNFalpha therapy and define its role in the management of PG, with or without accompanying IBD.