Tumour necrosis factor and inflammatory bowel disease

Response to infliximab therapy in ulcerative colitis is associated with decreased monocyte activation, reduced CCL2 expression and downregulation of Tenascin C

BACKGROUND AND AIMS

The cellular mechanisms leading to infliximab therapy response in patients with ulcerative colitis (UC) are incompletely known. We therefore investigated early effects of infliximab therapy on monocytes and associated chemokines linked to clinical therapy response in UC patients.

METHODS

Blood and biopsies were obtained from anti-TNF therapy-naïve UC patients (n = 43) before (baseline) and during induction therapy with infliximab. Therapy response was evaluated at Week 14. Expression of monocyte activation markers and levels of chemokines in serum and biopsies were determined. Quantitative proteomic analysis was performed in cultured mucosal biopsies, and obtained data was validated in serum.

RESULTS

In therapy responders, but not in non-responders, infliximab reduced blood monocyte expression of CD14 and CD86, 2 weeks after therapy commenced, relative to baseline. Serum CCL2 levels were decreased only among therapy responders at Week 2 and Week 14, relative to baseline. These data corresponded with lower levels of CD14, CD86 and CCL2 in intestinal tissue in responders as compared with non-responders at Week 14. Proteomic analysis of cultured biopsies showed that infliximab induced a reduction in Tenascin C that predicted downregulation of CCL2. Therapy responders, but not non-responders, had decreased serum Tenascin C levels at Week 2 and Week 14, relative to baseline.

CONCLUSIONS

Infliximab therapy response in UC patients is associated with reduced monocyte activation and serum levels of CCL2 2 weeks after therapy commencement. In therapy responders, infliximab influenced Tenascin C, which might be a regulator of CCL2 expression and important for induction of the clinical therapy response.

The association between three promoter polymorphisms of IL-10 and inflammatory bowel diseases (IBD): a meta-analysis

AIM

To assess the relationship of the Interleukin-10 (IL-10) -1082G/A (rs1800896), -819C/T (rs1800871) and -592C/A (rs1800872) polymorphism with inflammatory bowel disease (IBD) by means of meta-analysis.

METHODS

Published data addressing the association between polymorphism of the IL-10 with Crohn's disease (CD) and Ulcerative colitis (UC) were selected from electronic databases. A total of 17 studies including 4132 cases and 5109 controls were included in this meta-analysis which detected whether -1082G/A, -819C/T and -592C/A polymorphism were associated with CD or UC susceptibility.

RESULT

The IL-10 -819C/T and -519C/A variant allele observed a significant association with UC (OR 1.16, 95%CI 1.03-1.31 and OR 1.19, 95%CI 1.03-1.38) not CD while there is no significant association between -1082G/A and UC or CD.

CONCLUSION

The IL-10 -819C/T and -592C/A polymorphisms contribute to susceptibility to UC, but IL-10 -1082G/A polymorphism neither associated with CD nor UC.

Overview of biologic therapy for Crohn's disease

Therapy for Crohn's disease (CD) is evolving at breakneck speed. Biologic therapies are assuming ever more important roles in treating this unrelenting, life-long disorder. New evidence suggests that earlier, more aggressive use of biological therapies for CD may improve overall efficacy rates, as well as reduce long-term complications. In addition to optimizing the use of older biologic therapies (antibodies against TNF-alpha), recent and ongoing clinical trials are evaluating the clinical efficacy of a large number of other biologic therapies, honing in on a wide array of immunological targets. The promise of biologic therapies stems from their ability to induce complete and long-lasting remission of symptoms in a way that 'standard' therapies have not been able to accomplish. In this review of biologic therapies for CD, we examine the latest clinical trial data and evidence for mechanism of action of a variety of current and future therapies.

Infliximabe na doença de crohn: experiência clínica de um centro terciário paulista

INTRODUÇÃO: Na Doença de Crohn (DC) ocorre uma reatividade anormal dos linfócitos T da mucosa intestinal e produção excessiva de citocinas pró-inflamatórias, entre as quais o fator de necrose tumoral alfa (TNF-á). O infliximabe é um anticorpo monoclonal anti-TNF-á indicado no tratamento de pacientes com DC fistulizante ou não responsiva ao tratamento convencional. OBJETIVOS: Caracterizar as indicações clínicas do infliximabe na DC em um serviço referencial paulista, avaliando padrões de resposta e a efetividade do tratamento através do Índice de Atividade da DC (CDAI). PACIENTES E MÉTODOS: O estudo foi observacional retrospectivo e analisou dados de 21 pacientes com DC em uso de infliximabe atendidos no Hospital de Base de Rio Preto entre janeiro de 2004 e julho de 2008. RESULTADOS: Houve predomínio de pacientes do sexo feminino (67%), com média de idade de 33 anos. As indicações mais freqüentes foram fístulas perianais (48%). Resposta clínica total à droga ocorreu em 43% dos pacientes, e resposta parcial em 47%; a diferença da média do CDAI entre os grupos antes e após o tratamento foi de 244,61 pontos (p< 0,0005). CONCLUSÕES: O infliximabe induziu melhora clínica em 90% dos pacientes, acompanhada de redução da atividade da doença na avaliação através de um índice padronizado.

Cyclosporine treatment of anal furunculosis in 26 dogs

OBJECTIVES

To evaluate the effect of cyclosporine on anal furunculosis lesions in 26 dogs.

METHODS

Lesions were graded as mild in 11 dogs, moderate in eight and severe in seven. Each dog was treated with approximately 4 mg/kg cyclosporine orally every 12 hours until the lesions resolved or showed no further improvement. Residual lesions were resected surgically.

RESULTS

Eighteen dogs (69 per cent) experienced complete resolution, seven (27 per cent) improved but had residual lesions and one (4 per cent) showed no improvement. The mean duration of treatment until resolution or no further improvement was 8.8 weeks (range four to 24 weeks). Nine dogs (35 per cent) experienced recurrence. Six were from the group that had shown complete resolution and three were from the group that had surgery. Fifteen dogs (58 per cent) developed side effects to cyclosporine, although none required treatment to be discontinued. Mean duration of follow-up was 6.8 months (range one to 20 months).

CLINICAL SIGNIFICANCE

Cyclosporine was effective at resolving or reducing anal furunculosis lesions in 25 of 26 dogs (96 per cent). However, residual or recurrent lesions remain a potential problem, and surgical resection or long-term cyclosporine treatment may be necessary in some dogs.

Inhibition of MAP kinases by crude extract and pure compound isolated from Commiphora mukul leads to down regulation of TNF-alpha, IL-1beta and IL-2

The anti-inflammatory effect of the medicinal plant, Commiphora mukul gum was studied in peripheral blood mononuclear cells (PBMC). Bioassay-guided fractionation using conventional solvent extraction procedures, subsequent column fractionation, followed by monitoring specific activity in PBMC led to the isolation of a lead compound. Both crude ethyl acetate extract and the lead compound, thus isolated, showed inhibitory effect on proliferative response of PBMC in mitogenic lymphocyte proliferation and MLR assays. Further studies on inflammatory mediators such as IFN-gamma, IL-12, TNF-alpha, IL-1beta and NO showed down regulation, whereas no inhibition was observed in the case of anti-inflammatory cytokine IL-10. Immunoblot analysis revealed the inhibitory effect of crude ethyl acetate extract on phosphorylation of all the three mitogen activated protein kinases (MAPK) such as ERK, JNK and p38 MAPK. In contrast treatment with pure compound showed no inhibitory effect on ERK. c-fos and c-jun mRNA levels were also reduced in PMA stimulated cells on treatment with crude extract and pure compound. This reduction in c-fos and c-jun levels, when taken together with inhibition of MAPK activation, provides a possible mechanism by which both crude ethyl acetate extract and purified compound isolated from C. mukul exert its action.

A new family of synthetic diterpenes that regulates cytokine synthesis by inhibiting IkappaBalpha phosphorylation

The synthesis and the biological evaluation of a new family diterpenes are presented. The synthetic studies were inspired by the structural framework of acanthoic acid (1) and yielded a family of compounds that were evaluated as anti-inflammatory agents. Among them, compounds 2, 10, 12, and 16 exhibited a very low nonspecific cytotoxicity and inhibited the synthesis of TNF-alpha with greater than 65 % efficacy at low micromolar concentrations. Cytokine-specificity studies revealed that these compounds also inhibited the synthesis of the proinflammatory cytokines IL-1beta and IL-6, while inhibition of IL-1ra and IL-8 synthesis was marginal and only occurred at high concentrations. Further studies, through EMSA and Western blot analyses, indicated that these compounds decreased the extent of phosphorylation of IkappaBalpha; this suggests that they exert their anti-inflammatory profile by inhibiting NF-kappaB-mediated cytokine synthesis. These findings imply that these diterpenes represent promising leads for the development of novel anti-inflammatory agents.

Activation of PPAR gamma and delta by conjugated linoleic acid mediates protection from experimental inflammatory bowel disease

BACKGROUND & AIMS

The molecular targets for the protective actions of conjugated linoleic acid (CLA) on experimental inflammatory bowel disease (IBD) are unknown. We used a loss-of-function approach to investigate whether CLA ameliorated colitis through a peroxisome proliferator-activated receptor gamma (PPAR gamma)-dependent mechanism.

METHODS

The expression of PPAR gamma, delta, and their target genes in the colon of mice fed control or CLA-supplemented diets was assayed after a 7-day dextran sodium sulfate (DSS) challenge by quantitative real-time polymerase chain reaction (PCR). Additionally, nuclear factor-kappa B (NF-kappaB) p65 activation was quantified in the colon. To determine the involvement of PPAR gamma in the mechanism of action of CLA directly, specific deletions of PPAR gamma in the colon were performed in mice by using the Cre-lox recombination system. Colonic PPAR gamma null mice and wild-type littermates were fed either a CLA-supplemented or a control diet for 42 days and challenged with 2.5% DSS. The therapeutic efficacy of CLA also was examined by using the CD4 + CD45RB hi transfer colitis model.

RESULTS

CLA induced PPAR gamma and delta, transcriptionally modulated PPAR gamma and delta-responsive gene clusters involved in lipid metabolism (uncoupling protein [UCP]1, UCP3, PPAR gamma coactivator 1alpha [PGC-1alpha], and CD36) and epithelial cell maturation (Gob-4 and Keratin 20). Additionally, CLA repressed tumor necrosis factor alpha (TNF-alpha) expression and NF-kappaB activation while inducing the immunoregulatory cytokine transforming growth factor beta 1 (TGF-beta 1 ). Clinically, CLA ameliorated DSS- and CD4 + -induced colitis. Loss of the PPAR gamma gene in the colon abrogated the beneficial effects of CLA in DSS colitis.

CONCLUSIONS

Our studies provide molecular evidence in vivo, suggesting that CLA ameliorates colitis through a PPAR gamma-dependent mechanism.

Synthesis of a novel family of diterpenes and their evaluation as anti-inflammatory agents

The synthesis and biological evaluation of a new family of diterpenes, represented by structures 2 and 3, is presented. These compounds constitute isomeric analogues of acanthoic acid (1) and were examined as potent anti-inflammatory agents. Among them, methyl ester 12 exhibited a low non-specific cytotoxicity, inhibited TNF-alpha synthesis and displayed good specificity in suppressing cytokine expression.

Treating Crohn's disease by inducing T lymphocyte apoptosis

Apoptosis is one of the most important regulatory mechanisms in immunological homeostasis. Disturbances in the apoptotic pathways lead to autoimmune disease. Crohn's disease is a chronic inflammatory bowel disease of unknown origin, which seems to be mediated by excessive T cell-mediated immunity. Recently, disturbances in apoptotic pathways of lamina propria T lymphocytes of patients with Crohn's disease have been identified. In the uninflamed, normal intestinal mucosa, lamina propria (LP) T cells are susceptible to activation-induced cell death, but these cells show a resistance to apoptosis based on several disturbances compared to controls. Recently, intriguing data were published using cytokine-targeted therapy (anti-IL12, anti-IL6 receptor, anti-TNF). Actually, these medications restored mucosal immunological imbalance by inducing apoptosis of the LP T cells and seemed to be beneficial in models of Crohn's disease. In this review, mechanisms of immunological homeostasis will be discussed. We will also discuss the fascinating new results of cytokine-targeted therapy in animal models of Crohn's disease and the effects of these drugs in patients with Crohn's disease.

Proliferative response of different human osteoblast-like cell models to proinflammatory cytokines

Children with inflammatory bowel disease are known to be at risk of osteopenia. The cause of this osteopenia is likely to be multifactorial, but the inflammatory process with its characteristic overproduction of cytokines has been implicated. To investigate this possible contribution of the disease activity to the development of osteopenia, we performed in vitro assays of the proliferation of osteoblast-like cells of differing origins in response to the inflammatory cytokines tumor necrosis factor-alpha and IL-1/beta. Osteoblast-like cells derived from pediatric bone explants, adherent stromal cells derived from bone marrow (osteoprogenitors), MG-63 osteosarcoma cells, and SV-40 virally transformed osteoprogenitor cells (HCC1) were studied. Tumor necrosis factor-alpha stimulated the proliferation of cells in primary cultures (i.e. from explants and marrow samples) in a linear, dose-dependent manner. In contrast, inhibition of proliferation was observed with the established cell lines (MG-63 and HCC1). IL-1beta stimulated proliferation of all cells apart from the immortalized human bone marrow cell line, HCC1, in which case potent inhibition was observed. We conclude that proinflammatory cytokines are potent regulators of osteoblast-like cell proliferation, and that the responses are specific to cell type. The opposite results obtained with established cell lines compared with the primary cultures suggest that careful consideration should be given to choosing the most suitable cell line for in vitro studies relating to in vivo mechanisms predisposing to osteopenia.

Use of infliximab in the treatment of Crohn's disease in children and adolescents

BACKGROUND

Crohn's disease is often poorly responsive to conventional therapy with corticosteroids and immunomodulators. A novel chimeric antibody to tumor necrosis factor-alpha, infliximab, has shown utility in the treatment of refractory Crohn's disease in adults.

PURPOSE

To evaluate the efficacy of open-label administration of infliximab in children and adolescents with active intestinal Crohn's disease.

METHODS

Chart review of the experience with 19 subjects (mean age 14.4 years, range 9 to 19 years) receiving 1 to 3 infusions of infliximab (5 mg/kg/dose) over a 12-week period for corticosteroid-resistant disease (n = 7) or corticosteroid dependence (n = 12). Disease activity was monitored by physician global assessment and the Pediatric Crohn's Disease Activity Index.

RESULTS

Significant initial improvement (first 4 weeks after infusion) was noted in all subjects, with Pediatric Crohn's Disease Activity Index values decreasing significantly (mean +/- SD, 42.1 +/- 13.7 to 10.0 +/- 5.6, P <.0001). Over the subsequent 8-week period, 8 of 19 treated subjects had worsening of symptoms, although none deteriorated to severe activity. The mean Pediatric Crohn's Disease Activity Index at 12 weeks was 26.8 +/- 16. 4. The mean daily prednisone dosages at baseline, 4 weeks, and 12 weeks were 28 +/- 14 mg, 20 +/- 12 mg, and 8 +/- 12 mg, respectively (P <.01). Adverse effects were noted in 3 patients during infusion (dyspnea, rash) and were self-limited.

CONCLUSIONS

Infliximab is associated with short-term clinical improvement in children and adolescents with severe Crohn's disease. The rapid return of disease activity in some patients suggests that additional dosing strategies may be required. Long-term safety necessitates close monitoring.

Inflammatory Bowel Disease: Current Pharmacotherapy Issues

Inflammatory bowel disease (IBD) includes two idiopathic syndromes, ulcerative colitis and Crohn's disease. In ulcerative colitis, inflammation is limited to the colonic mucosa and submucosa. Crohn's disease may, however, involve the small intestine, all bowel wall layers, and the upper gastrointestinal tract. Because health-related quality of life is significantly impaired during active disease, pharmaceutical care. is important in patient management. Traditional therapy includes 5-aminosalicylates, corticosteroids, and antimicrobial therapy. In steroid-resistant active disease, immunosuppressants (cyclosporine, azathioprine, 6-mercaptopurine, methotrexate) have a role but possess significant toxicity profiles. Current research focuses on the role of inflammatory mediators in IBD. Investigational therapies include monoclonal antibodies to proinflammatory cytokines, inhibitory cytokines, and anti-CD4 monoclonal antibodies.

Interleukin-10 (IL-10) genotypes in inflammatory bowel disease

Interleukin-10 (IL-10) is an anti-inflammatory cytokine. Its production in humans is under genetic control, and genotype defines high or low producers of this cytokine. This study addresses the hypothesis that idiopathic inflammatory bowel disease (IBD) patients are more likely to have the low IL-10 producer genotype and phenotype. DNA was extracted from blood cells of patients with Crohn's disease (CD) or with ulcerative colitis (UC) for IL-10 genotyping. The frequency of the high IL-10 producer allele (-1082*G) was decreased in the whole IBD group (41% vs. 51%, P = 0.03) and in the UC patients compared with normal controls (37% vs. 51%; P = 0.04). Hence, there appears to be an association between the IL-10 genotypes and IBD. This suggests that individuals genetically predisposed to produce less IL-10 are at a higher risk of developing IBD, in particular, UC.

Fecal tumor necrosis factor alpha, eosinophil cationic protein and IgE levels in infants with cow's milk allergy and gastrointestinal manifestations

Infants with atopic eczema exhibit a specific fecal protein pattern after oral challenge with cow's milk, characterized by an increase in both eosinophil cationic protein (ECP) and tumor necrosis factor (TNF)alpha. The aim of our study was to determine the pattern of these proteins in allergic infants with intestinal manifestations. TNFalpha, ECP and immunoglobulin E (IgE) were measured in stools from 13 infants with intestinal symptoms and 10 healthy infants. The allergic infants underwent two stool collections, one before a cow's milk challenge and the other after the challenge, either at the onset of clinical manifestations (n=6) or 15 days after the challenge if no clinical manifestations occurred (n=7). Baseline TNFalpha, ECP and IgE levels were low in all infants. The concentration of TNFalpha increased after the challenge in infants positive to challenge (p<0.05) but not in those negative to challenge. ECP and IgE levels remained low after the challenge in all the allergic infants. These data confirm that fecal TNFalpha and ECP levels indicate various reaction types of food allergy and that different immunologic disturbances lead to atopic eczema or intestinal symptoms during food allergy. Fecal protein pattern can thus be a useful tool in diagnosing food allergy in infants with intestinal manifestations.