The basis of current and future therapy for inflammatory bowel disease

The unsaponifiable fraction of extra virgin olive oil promotes apoptosis and attenuates activation and homing properties of T cells from patients with inflammatory bowel disease

The unsaponifiable fraction (UF) of extra virgin olive oil (EVOO) possesses anti-inflammatory properties and exerts preventative effects in murine models of inflammatory bowel disease (IBD). The present study was designed to determine the in vitro effects of UF on blood and intestinal T cells from IBD patients and healthy subjects. The T cell phenotype was investigated by flow cytometry and cytokine secretion was determined by ELISA. The presence of UF of EVOO promoted apoptosis and attenuated activation of intestinal and blood T cells isolated from IBD patients, decreasing the frequency of CD69(+) and CD25(+) T cells and, also, the secretion of IFN-γ. Moreover, UF reduced the expression of the gut homing receptor integrin β7 on blood T cells from IBD patients. In conclusion, UF modulates the activity and the gut homing capacity of T cells, and might therefore be considered as a dietary complement with an anti-inflammatory role in IBD patients.

Knockout of Ste20-like proline/alanine-rich kinase (SPAK) attenuates intestinal inflammation in mice

Inflammatory bowel diseases are characterized by epithelial barrier disruption and alterations in immune regulation. Ste20-like proline/alanine-rich kinase (SPAK) plays a role in intestinal inflammation, but the underlying mechanisms need to be defined. Herein, SPAK knockout (KO) C57BL/6 mice exhibited significant increases in intestinal transepithelial resistance, a marked decrease in paracellular permeability to fluorescence isothiocyanate-dextran, and altered apical side tight junction sodium ion selectivity, compared with wild-type mice. Furthermore, the expression of junction protein, claudin-2, decreased. In contrast, expressions of occludin, E-cadherin, β-catenin, and claudin-5 increased significantly, whereas no obvious change of claudin-1, claudin-4, zonula occludens protein 1, and zonula occludens protein 2 expressions was observed. In murine models of colitis induced by dextran sulfate sodium and trinitrobenzene sulfuric acid, KO mice were more tolerant than wild-type mice, as demonstrated by colonoscopy features, histological characteristics, and myeloperoxidase activities. Consistent with these findings, KO mice showed increased IL-10 levels and decreased proinflammatory cytokine secretion, ameliorated bacterial translocation on treatment with dextran sulfate sodium, and regulation of with no lysine (WNK) kinase activity. Together, these features may reduce epithelial permeability. In conclusion, SPAK deficiency increases intestinal innate immune homeostasis, which is important for control or attenuation of pathological responses in inflammatory bowel diseases.

The role of adipose tissue-associated macrophages and T lymphocytes in the pathogenesis of inflammatory bowel disease

Inflammatory bowel diseases (IBDs) are chronic inflammatory disorders of the gastrointestinal tract that affect more than 3 million people worldwide, but the pathological etiology is still unknown. The overall purpose of our investigations was to elucidate the possibility of pathological causes of IBD, and therefore, we determined the difference of inflammatory cytokine profiles in adipose tissue macrophages (ATMs) and T lymphocytes (ATTs) obtained near active lesions of IBD; investigated whether the alteration in ATM activation induces genes involved in collagen formation; and evaluated the effects of fatty acid oxidation inhibitors on factors involved in inflammation and collagen production by ATMs in IBD. Adipose tissues (ATs) were collected near active lesions and also at the margin of resected segments of the bowel from IBD patients with ulcerative colitis (UC) and CD (n=14/group). Normal appearing ATs from control subjects (n=14) who had colon resection for adenocarcinoma were collected as far away from the cancer lesion as possible to rule out possible changes. Compared with inactive disease lesions, ATMs and ATTs from active lesions released more IL-6, IL-4 and IL-13. Treatments of cytokine IL-4 and/or IL-13 to ATMs reduced iNOS expression but increased Arg-I expression which were exacerbated when treated with T cell- and adipocyte-conditioned medium. However, fatty acid oxidation inhibitors prevented the effects of cytokines IL-4 and/or IL-13 on iNOS and Arg-I expressions. This study was the first to show the effect of IL-4 and IL-13 on collagen formation, through iNOS and Arg-I expressions, that was exacerbated in a condition that mimics in vivo condition of active lesions. Moreover, our study was the first to provide potential benefits of fatty acid oxidation inhibitors to ATMs on preventing collagen formation; thus, providing therapeutic implications for individuals with intestinal fibrosis and stricture lesions, although future study should be guaranteed to elucidate the underlying mechanisms.

Protective effects of lithium on acetic acid-induced colitis in rats

Inflammatory bowel disease (IBD) is a multifactorial disease with unknown etiology characterized by oxidative stress, leukocyte infiltration, and rise in inflammatory cytokines such as tumor necrosis factor (TNF-alpha). Lithium, as a therapeutic agent for bipolar disorder, exerts some anti-inflammatory properties. In this study we have investigated the effects of lithium on acetic-acid-induced colitis in rats. Lithium (5, 10, and 20 mg/kg) was administered 1 h before the introduction of acetic acid. Colonic status was investigated 24 h following colitis induction through macroscopic, histological, and biochemical analyses. Lithium (20 mg/kg) ameliorated macroscopic and microscopic scores. These observations were accompanied by a reduction in the degree of both neutrophil infiltration, indicated by decreased myeloperoxidase activity, and lipid peroxidation, as measured by a decline in malondialdehyde content in inflamed colon as well as a decrease in TNF-alpha levels. These findings suggest that lithium exerts beneficial effects on experimental colitis and therefore might be useful in the treatment of IBD.

Temporal and spatial analysis of clinical and molecular parameters in dextran sodium sulfate induced colitis

Background

Inflammatory bowel diseases (IBD), including mainly ulcerative colitis (UC) and Crohn's disease (CD), are inflammatory disorders of the gastrointestinal tract caused by an interplay of genetic and environmental factors. Murine colitis model induced by Dextran Sulfate Sodium (DSS) is an animal model of IBD that is commonly used to address the pathogenesis of IBD as well as to test efficacy of therapies. In this study we systematically analyzed clinical parameters, histological changes, intestinal barrier properties and cytokine profile during the colitic and recovery phase.

Methods

C57BL/6 mice were administered with 3.5% of DSS in drinking water for various times. Clinical and histological features were determined using standard criteria. Myeloperoxidase (MPO) activity, transepithelial permeability and proinflammatory mediators were determined in whole colon or proximal and distal parts of colon.

Results

As expected after administration of DSS, mice manifest loss of body weight, shortening of colon length and bloody feces. Histological manifestations included shortening and loss of crypts, infiltration of lymphocytes and neutrophil, symptoms attenuated after DSS withdrawal. The MPO value, as inflammation indicator, also increases significantly at all periods of DSS treatment, and even after DSS withdrawal, it still held at very high levels. Trans-mucosal permeability increased during DSS treatment, but recovered to almost control level after DSS withdrawal. The production of proinflammatory mediators by colonic mucosa were enhanced during DSS treatment, and then recovered to pre-treated level after DSS withdrawal. Finally, enhanced expression of proinflammatory mediators also revealed a different profile feature in proximal and distal parts of the colon.

Conclusion

Experimental colitis induced by DSS is a good animal model to study the mechanisms underlying the pathogenesis and intervention against IBD, especially UC.

TGF-beta1 gene transfer to the mouse colon leads to intestinal fibrosis

Crohn's disease (CD) is a chronic, relapsing inflammatory bowel disease, characterized by transmural inflammation. In CD, the recurrent inflammatory injury and tissue repair that occurs in the intestine can progress uncontrollably, leading to the proliferation of mesenchymal cells as well as fibrosis, characterized by excessive extracellular matrix deposition. These processes thicken the bowel wall, reducing flexibility, and often culminate in obstructive strictures. Because no effective measures are currently available to specifically treat or prevent intestinal stricturing, we sought to gain a better understanding of its pathogenesis by developing a mouse model of intestinal fibrosis. Because transforming growth factor (TGF)-beta1 can mediate both fibrosis and mesenchymal cell proliferation; we studied the effects of delivering adenoviral vectors encoding spontaneously active TGF-beta1 into the colons of mice. We first demonstrated that enema delivery of marker adenoviral vectors led to the transfection of the colonic epithelium and transient transgene expression. Histologically, control vectors caused an acute inflammatory response, involving the recruitment of neutrophils and mononuclear cells into the colonic lamina propria; however, infection caused little if any fibrosis. In contrast, the TGF-beta1 vector caused a more severe and prolonged inflammatory response as well as localized collagen deposition, leading to severe and progressive fibrosis. This was accompanied by the emergence of cells with a myofibroblast phenotype. Ultimately the fibrosis resulted in many of the TGF-beta1-transfected mice developing profound colonic obstruction. Through adenoviral gene transfer technology, we describe a novel mouse model of colitis and implicate TGF-beta1 in the pathogenesis of obstructive intestinal fibrosis.

PDE4 inhibition: a novel approach for the treatment of inflammatory bowel disease

Inflammation is a hallmark of inflammatory bowel disease (IBD), and elevation of cAMP levels can inhibit the pro-inflammatory and tissue-destructive properties of leukocytes. Phosphodiesterase 4 (PDE4) is the predominant enzyme that metabolizes cAMP in inflammatory cells, and the anti-inflammatory and immunomodulatory potential of PDE4 inhibitors in human leukocytes, endothelium and epithelium is well documented. Although PDE4 inhibitors have been investigated as treatments for several inflammatory diseases, this has focused mainly on asthma and chronic obstructive disease (COPD). Historically, their clinical utility has been limited by nausea and emesis. However, the PDE4 inhibitors cilomilast and roflumilast have recently shown efficacy in asthma and COPD, with a reduced propensity to cause nausea and emesis. In this review, we summarize for the first time the evidence that PDE4 inhibitors might have therapeutic benefit in IBD, and discuss mechanisms of action beyond the inhibition of inflammatory cells.

Efficacy of combined cyclosporine A and ketoconazole treatment of anal furunculosis

Cyclosporine A and ketoconazole were used as a combined therapy to treat 19 dogs with anal furunculosis. Complete resolution of all lesions was achieved in three to 10 weeks, but recurrences occurred in seven of the 19 dogs (36.8 per cent), with remission periods extending from one to six months for these dogs. Adverse effects of treatment included excessive hair loss, intermittent lethargy, vomiting and decreased appetite in some dogs, but none of the signs were considered serious. The results of treatment are comparable with, if not better than, the surgical alternatives. There is an approximate 70 per cent cost saving over the use of cyclosporine alone.

Regulation of gene expression in inflammatory bowel disease and correlation with IBD drugs: screening by DNA microarrays

Potential biomarkers for Crohn's disease (CD) and ulcerative colitis (UC) were identified from two sets of full thickness pathologic samples utilizing DermArray and PharmArray DNA microarrays relative to uninvolved (Un) colon or normal colon. Seven of the over-expressed genes were verified using quantitative RT-PCR (i.e., TMPT, FABP1, IFI27, LCN2, COL11A2, HXB, and metallothionein). By correlating gene expression profiles between inflammatory bowel disease (IBD) tissue samples and IBD drug-treated cell cultures it might be possible to identify new candidate molecular target genes for IBD therapy and drug discovery. Potential biomarkers for CaCo2 cell cultures, which are routinely used as a GI tract surrogate model for in vitro pharmacokinetic studies, treated with azathioprine, 5-aminosalicylic acid, metronidazole, and prednisone were also identified from another experiment. Metallothionein mRNA expression was found to be down-regulated in azathioprine-treated CaCo2 cells, and was coincidentally up-regulated in the CD sample, thus resulting in an anti-correlation. These results suggest that this new screening methodology is feasible, that metallothioneins might be biomarkers for azathioprine therapy in vivo in CD, and that azathioprine might mechanistically down-regulate metallothionein gene expression. Correlations were also observed between IBD samples and either metronidazole- or 5-aminosalicylic acid-treated CaCo2 cells. Similar comparisons of disease tissue samples in vivo vs drug-treated cell cultures in vitro might reveal new mechanistic insights concerning established or experimental drug therapies. This affordable in vitro methodology is promising for expanded studies of IBD and other diseases.

Pharmacogenomics of response to anti-tumor necrosis factor therapy in patients with Crohn's disease

The relatively recent development of genetically engineered agents has the potential to alter the treatment of Crohn's disease radically, and drugs that inhibit tumor necrosis factor-alpha (TNFalpha) have been introduced as a new therapeutic class with high efficacy, rapid onset of action, prolonged effect, and improved tolerance. However these agents are expensive and at least one-third of the eligible patients fail to show any useful response. Finding a means to predict those who will respond, and to anticipate relapse are, therefore, of obvious importance. T helper-type 1 (Th1) lymphocytes orchestrate much of the inflammation in Crohn's disease mainly via production of TNFalpha, which appears to play a pivotal role as a pro-inflammatory cytokine. It exerts its effects through its own family of receptors (TNFR1 and TNFR2), the end results of which include apoptosis, c-Jun N-terminal kinase/stress-activated protein kinase (JNK/SAPK) activation and NF-kappaB activation. Activated NF-kappaB enters the nucleus and induces transcription of genes associated with inflammation, host defense and cell survival. The promoter region of the TNF gene lies between nucleotides -1 and -1300, and encompasses numerous polymorphic sites associated with potential binding sites for various transcription factors. Carriers of the TNF allele 2 (TNF2), which contains a single base-pair polymorphism at the -308 promoter position, produce slightly more TNFalpha in their intestinal mucosa than non-TNF2 carriers. TNF polymorphisms also appear to influence the nature and frequency of extraintestinal manifestations of inflammatory bowel disease (IBD). A number of routes of inhibition of TNF are being investigated. Most extensively evaluated is the use of monoclonal antibodies against TNFalpha (e.g. infliximab). Several large controlled trials indicate that infliximab has a role in treating patients with moderate to severely active Crohn's disease and in fistulating Crohn's disease. Although it would be useful to genetically differentiate 'responders' from 'non-responders,' currently there are few published data on TNF polymorphisms in IBD, and often only selected polymorphisms are genotyped. Small studies have shown possible associations between poor response to infliximab and increasing mucosal levels of activated NF-kappaB, homozygosity for the polymorphism in exon 6 of TNFR2 (genotype Arg196Arg), positivity for perinuclear antineutrophil cytoplasmic antibodies (ANCA), and with the presence of increased numbers of activated lamina propia mononuclear cells producing interferon-gamma and TNFalpha. This is a rapidly changing field, and more information of greater direct clinical benefit can be expected soon.

Recombinant human interleukin 10 in the treatment of patients with mild to moderately active Crohn's disease. The Interleukin 10 Inflammatory Bowel Disease Cooperative Study Group

BACKGROUND & AIMS

Interleukin 10 (IL-10) is an anti-inflammatory, immunomodulatory cytokine that regulates mucosal inflammation. This study evaluated the safety, tolerance, and efficacy of recombinant human IL-10 (rhuIL-10) for mild to moderately active Crohn's disease.

METHODS

We conducted a 24-week multicenter, prospective, randomized, double-blind, placebo-controlled, and sequential-escalating-dose study. Ninety-five patients with Crohn's Disease Activity Index of 200-350, not presently undergoing corticosteroid, mesalamine, or immunosuppressive therapy, were treated with subcutaneous rhuIL-10 (1, 5, 10, or 20 microg/kg) or placebo once daily for 28 consecutive days. Patients were followed up for 20 weeks after treatment. Evaluation of safety and tolerance was the first objective, and efficacy was the second objective.

RESULTS

Adverse effects were dose-related, mild-to-moderate in severity, and reversible. Asymptomatic and reversible anemia and thrombocytopenia were observed at higher doses. No withdrawal or delayed adverse effects were evident during 20 weeks of follow-up. At the end of treatment (day 29), intent-to-treat analysis showed that 23.5% (confidence interval [CI], 6.8%-49.9%) of patients receiving 5 micro/kg rhuIL-10 experienced clinical remission and endoscopic improvement; 0% (CI, 0%-14.8%) of patients in the placebo group did. Higher doses of recombinant human IL-10 were less effective than 5 microg/kg. No rhuIL-10 serum accumulation and no antibody against IL-10 were detected after 4 weeks.

CONCLUSIONS

Subcutaneous rhuIL-10 administered daily for 28 days to patients with mild to moderately active Crohn's disease is safe, well-tolerated, and shows clinical and endoscopic improvement.

Role of cytokines in the pathogenesis of inflammatory bowel disease

Recent advances in the drug treatment of inflammatory bowel disease (IBD) have paralleled our understanding of the pathophysiology of ulcerative colitis and Crohn's disease. Several proinflammatory and immune-regulatory cytokines are upregulated in the mucosa of patients with IBD, and differences and similarities in the cytokine profiles of ulcerative colitis and Crohn's disease have been elucidated. Several clinical trials involving a chimeric anti-TNF-alpha (tumor necrosis factor-alpha) antibody have shown marked clinical benefit in the majority of patients with Crohn's disease, verifying the importance of TNF-alpha in the pathogenesis of Crohn's disease. In preliminary studies, treatment with recombinant human interleukin-10 has been beneficial in Crohn's disease but not in ulcerative colitis. Future treatment of IBD may include combination or sequential cytokine and anticytokine administration in defined groups of patients based on their mucosal cytokine profiles.

The effect of dexamethasone treatment on murine colitis

BACKGROUND

Corticosteroids are used as anti-inflammatory drugs in the treatment of inflammatory bowel disease. We wanted to know whether dexamethasone (DEX) treatment could prevent dextran sulphate sodium (DSS)-induced colitis in mice.

METHODS

Acute colitis was induced after oral administration of 10% DSS for 2 days. Controls received normal tap water. Five days before and during DSS or tap water exposure half the group was treated with 0.06 mg/day DEX, and the other half received saline. After the mice had been killed, macroscopic observation and histologic evaluation were used to determine the degree of colonic inflammation.

RESULTS

The macroscopic score was significantly increased in untreated DSS mice (P < 0.001). The induction of colitis was not prevented by DEX pretreatment (5.9 +/- 0.9 versus 4.2 +/- 0.6; NS). In addition, the macroscopic scores of DEX-treated controls were significantly increased (1.8 +/- 0.2 versus 0.7 +/- 0.2; P = 0.007), which suggests that DEX has a stimulating effect on colitis induction. The histology score was significantly increased in untreated DSS mice compared with controls (P = 0.016). Analogous to the macroscopic scoring results, the histology score of DEX-treated controls was significantly increased compared with untreated controls (P = 0.046).

CONCLUSIONS

Pretreatment with dexamethasone did not prevent the induction of acute DSS colitis, reflected by both aggravated macroscopic and histologic inflammation scores.

Cyclosporin as the sole treatment for anal furunculosis: preliminary results

Cyclosporin was used, as the sole agent, to treat six cases of anal furunculosis, allowing the clinical response to the drug to be evaluated. The initial dose was 7.5 mg/kg twice a day. Following one week of treatment, whole blood cyclosporin trough levels were measured and the dose was adjusted to obtain a stable trough level of 400 to 600 ng/ml. In all dogs, the lesions were found to follow a similar pattern of resolution throughout the course of treatment. The presenting signs disappeared within one week of treatment, with a reduction in lesion size of 50 to 90 per cent. Lesions then gradually healed over the remainder of the treatment, which lasted from 10 to 20 weeks. One case required cryosurgical treatment to resolve a 2 mm diameter persistent ulcerated lesion following 18 weeks of treatment. The length of follow-up was four to 14 months (mean 7.7 months). One case developed recurrence of the lesions eight weeks post-treatment.

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.

Therapeutic potential of infliximab in inflammatory bowel disease

Traditional treatment approaches for patients with inflammatory bowel disease involve 1) pharmacologic management with aminosalicylates, corticosteroids, immunomodulatory agents, and antibiotics; and 2) nonpharmacologic management by surgical and dietary means. Complications and inadequate responses to current treatment modalities have resulted in the development of new and more specific biologic therapies. The proinflammatory cytokine tumor necrosis factor alpha (TNF alpha) is present in elevated concentrations in patients with inflammatory bowel disease; therefore, it has been targeted for treatment approaches. Infliximab is a chimeric, monoclonal antibody to TNF alpha developed to inhibit the interaction of TNF alpha with its receptor, to result in amelioration of inflammation. This biologic agent has received the most attention and is the most studied of those for the treatment of patients with Crohn's disease. This article reviews the symptoms of inflammatory bowel disease, the traditional treatment approaches used, the role of TNF alpha in disease pathogenesis, and the value of infliximab in treatment.

The role of IL-10 in inflammatory bowel disease: "of mice and men"

Inflammatory bowel disease (IBD) is a generic term typically used to describe a group of idiopathic inflammatory intestinal conditions in humans that are generally divided into Crohn's disease and ulcerative colitis. Although the etiology of these diseases remains unknown, a number of rodent models of IBD have recently been identified, all sharing the concept that the development of chronic intestinal inflammation occurs as a consequence of alterations in the immune system that lead to a failure of normal immunoregulation in the intestine. On the basis of these models, it has been hypothesized that the development of IBD in humans may be related to a dysregulated immune response to normal flora in the gut. Immunodeficient scid mice injected with CD4+ CD45RB(high) T cells and mice deficient in interleukin (IL)-10 (IL-10-/-) are among the rodent models of IBD. In both models, there is inflammation and evidence of a Th1-like response in the large intestine, characterized by CD4+ T-cell and macrophage infiltrates, and elevated levels of interferon-gamma. Because IL-10 is an immunomodulatory cytokine that is capable of controlling Th1-like responses, the role of IL-10 was investigated in these models. IL-10 was shown to be important in regulating the development of intestinal inflammation in both models. These results provided key data that supported initiation of clinical trials evaluating the efficacy of IL-10 in patients with IBD.

Cutting Edge: Curative Treatment of an Experimentally Induced Colitis by a CD44 Variant V7-Specific Antibody

Inflammatory bowel disease is a quite severe chronic inflammation, treated mainly by immunosuppression, which often has serious side effects. As CD44 is important in lymphocyte activation and migration, we asked whether Abs against CD44 isoforms influence trinitrobenzenesulfonic acid (TNBS)-induced colitis in mice. A lethal colitis (73/111 mice) could be prevented in 69 of 97 mice by anti-CD44v7 (CD44 variant isoform v7), whereas anti-CD44s (CD44 standard isoform) and anti-CD44v6 had no effect. Upon receiving anti-CD44v7 after the disease had been fully exacerbated, &gt;90% of the mice recovered. TNBS plus anti-CD44v7-treated mice developed early signs of inflammation, with infiltration of leukocytes in the lamina propria and increased IFN-γ production. However, while control mice developed a severe pancolitis, the intestine fully regenerated in anti-CD44v7-treated mice. Locally and systemically, a strong increase in IL-10 production was noted. Thus, anti-CD44v7 can be regarded as a highly efficient and specific therapeutic reagent in chronic colitis, which probably functions by regulating an overshooting Th1 reaction.