Soluble tumour necrosis factor receptors p55 and p75 in the urine monitor disease activity and the efficacy of treatment of inflammatory bowel disease

Selection and Evaluation of mRNA and miRNA Reference Genes for Expression Studies (qPCR) in Archived Formalin-Fixed and Paraffin-Embedded (FFPE) Colon Samples of DSS-Induced Colitis Mouse Model

The choice of appropriate reference genes is essential for correctly interpreting qPCR data and results. However, the majority of animal studies use a single reference gene without any prior evaluation. Therefore, many qPCR results from rodent studies can be misleading, affecting not only reproducibility but also translatability. In this study, the expression stability of reference genes for mRNA and miRNA in archived FFPE samples of 117 C57BL/6JOlaHsd mice (males and females) from 9 colitis experiments (dextran sulfate sodium; DSS) were evaluated and their expression analysis was performed. In addition, we investigated whether normalization reduced/neutralized the influence of inter/intra-experimental factors which we systematically included in the study. Two statistical algorithms (NormFinder and Bestkeeper) were used to determine the stability of reference genes. Multivariate analysis was made to evaluate the influence of normalization with different reference genes on target gene expression in regard to inter/intra-experimental factors. Results show that archived FFPE samples are a reliable source of RNA and imply that the FFPE procedure does not change the ranking of stability of reference genes obtained in fresh tissues. Multivariate analysis showed that the histological picture is an important factor affecting the expression levels of target genes.

Cytokines in inflammatory bowel disease

Over the past decade, much has been learned regarding the role of various cytokines in the pathogenesis of inflammatory bowel disease. Several cytokine ‘knockout’ models in mice have been shown to develop colitis, while alterations in the production of various cytokines has been documented in human Crohn's disease and ulcerative colitis. In recent years, attempts have been made to treat these diseases through modulation of cytokine production or action. This review focuses on the cytokines that have been implicated in the pathogenesis of inflammatory bowel disease. The evidence for and against a role for particular cytokines in intestinal inflammation is reviewed, as is the experimental and clinical data suggesting that cytokines are rational targets for the development of new therapies.

Blocking TNF-α by combination of TNF-α- and TNFR-binding cyclic peptide ameliorates the severity of TNBS-induced colitis in rats

Tumor necrosis factor alpha (TNF-α) has been implicated in the pathogenesis of Crohn's disease. TNF antagonists are effectively used to treat these patients, although the efficiency of different antagonists varies. In the present study we combined TNF-α binding cyclic peptide (TBCP) and TNFR1 binding cyclic peptide (TRBCP) to treat TNBS-induced colitis in rats for one week. The symptoms of colitis including bloody diarrhea, rectal prolapse, and a profound and sustained weight loss were significantly ameliorated and the colon inflammatory damage, both macroscopic and histological scores, MPO activity, and NO production were markedly decreased in rats by neutralization of TNF-α and blocking TNFR1, as compared with those in rats treated with irrelevant peptide or normal saline (P<0.05). The transcripts of IL-1β and IL-8, and the protein expression of TNF-α in rats treated with both TBCP and TRBCP were also down-regulated (P<0.05), while these proinflammatory cytokines remained unchanged in rats treated with irrelevant peptide or normal saline. These findings suggest that the combination of TNF-α- and TNFR1-binding peptide effectively improves the symptoms of TNBS-induced colitis and alleviates colonic pathological damages in rats. This combination may be a potent candidate for clinical treatment of the inflammatory bowel disease.

Pentoxifylline suppresses the expression of tumor necrosis factor-α and interleukin-1β in ulcerative colitis in rats

AIM: To investigate the effects of pentoxifylline (PTX) on the expression of tumor necrosis factor-alpha (TNF-α) and interleukin-1β (IL-1β) in trinitrobenzene sulfonic acid (TNBS)-induced ulcerative colitis (UC) in rats.

METHODS: UC was induced in rats with TNBS and ethanol. The rats were randomly divided into three groups: normal group (C), TNBS group (T), and PTX group (D). Three days after UC was induced, the rats in the PTX group received a PTX injection every 12 hours for five consecutive days, while the remaining two groups received an injection of distilled water. The disease activity index (DAI) was evaluated daily. The expression of TNF-α and IL-1β mRNAs was measured by reverse transcription-polymerase chain reaction (RT-PCR).

RESULTS: Compared with the normal group and the PTX group, the expression of TNF-α and IL-1β mRNAs and DAI in the TNBS group were markedly higher (6.85 ± 2.78 vs 0.45 ± 0.11 and 1.85 ± 2.01; 1.02 ± 0.16 vs 0.61 ± 0.08 and 0.74 ± 0.16; and 0.95 ± 0.17 vs 0.57 ± 0.07 and 0.64 ± 0.13, respectively; all P < 0.05). No significant differences were noted in the expression levels of TNF-α and IL-1β mRNAs and DAI between the normal group and the PTX group (all P > 0.05).

CONCLUSION: The expression of proinflammatory factors TNF-α and IL-1β mRNAs increases in rat ulcerative colitis. PTX exerts protective effects against UC possibly by downregulating the expression of TNF-α and IL-1β mRNAs.

Role of TNF receptors, TNFR1 and TNFR2, in dextran sodium sulfate-induced colitis

BACKGROUND

In this study we determined the consequence of the absence of each TNF receptor, TNFR1 or TNFR2, in the dextran sulfate sodium (DSS) model of colitis.

METHODS

Wildtype (WT), TNFR1(-/-) and TNFR2(-/-) mice were fed 3% w/v DSS in drinking water for 5 days followed by 2 (day 7) or 7 (day 12) days of tap water.

RESULTS

The colons from untreated TNFR1(-/-) and TNFR2(-/-) mice were histologically normal. Following DSS, all strains became inflamed. TNFR1(-/-) mice had a more severe clinical score at days 8 and 9 compared to WT and TNFR2(-/-) mice despite similar histopathological damage in their colons. The more severe clinical score was associated with a reduced macrophage infiltration into the colonic mucosa. TNFR2(-/-) mice showed increased indicators of disease including increased colon weight, a shrunken cecum, and an increased number of ulcers compared to TNFR1(-/-) and WT strains at day 7. Mucosal levels of TNFR2 were elevated in colitic mice compared to uninflamed controls, with no difference between strains on day 7 but on day 12, unlike WT mice, levels were reduced in TNFR1(-/-) mice. There was no difference in the number of TUNEL-positive apoptotic colonic epithelial cells between strains, nor in total cleaved caspase 3 levels between strains, measured by Western blot of colon homogenates.

CONCLUSIONS

While deficiency of either receptor contributes to some measures of DSS colitis, the histopathological scores are similar, indicating that TNF receptors either do not play a major role or are redundant in the pathology associated with DSS colitis.

Does the urinary excretion of alpha1-microglobulin and albumin predict clinical disease activity in ulcerative colitis?

INTRODUCTION

There remains some difficulty in determining disease activity during the development of inflammatory bowel disease (IBD). The excretion levels of some inflammatory response molecules increase as a result of the onset of this disease. We studied urinary alfa-1-microglobulin (alpha1-MG) and albumin levels in patients with active and inactive ulcerative colitis (UC) and investigated whether we could use these parameters as an activity index.

METHODS

The study was carried out at Gazi University Faculty of Medicine, Nephrology and Gastroenterology Departments, between December 2003 and March 2006. In total, 35 patients (male/female: 16/19, mean age: 38.3+/-2.4 years) and 13 healthy controls (male/female: 6/7, mean age: 35.8+/-2.8 years) were enrolled in the study. Nineteen patients had symptoms of active disease and the remaining 16 patients had inactive disease.

RESULTS

There was a significant difference in serum C-reactive protein (CRP), urinary albumin excretion, and alpha1-MG excretion levels between patients and controls. Patients with active disease had significantly higher serum CRP and alpha1-MG levels than those with inactive disease and controls. Patients with active disease had higher microalbuminuria levels than inactive patients, but this difference was not statistically significant. Urinary albumin and alpha1-MG excretion did not correlate with serum CRP levels.

CONCLUSION

The present study suggests that, as with CRP, urinary levels of albumin and alpha1-MG increase during the active period of UC. During the inactive period, concentrations of these parameters are comparable to controls. The measurement of alpha1-MG and/or microalbuminuria could provide information on disease severity and response to treatment.

Serum soluble TNF receptor I and II levels correlate with disease activity in IBD patients

BACKGROUND

Tumor necrosis factor alpha (TNFalpha) is a proinflammatory cytokine and an important mediator in the pathophysiology of inflammatory bowel disease (IBD). The effects of TNFalpha are mediated by 2 specific receptors, a 55-kDa protein (TNF-RI) and a 75-kDa receptor (TNF-RII), which are usually bound to the cell surface. Soluble TNF receptors I and II (sTNF-RI + II) are released by proteolytic cleavage of the extracellular domains of these receptors. Soluble TNF-Rs act as TNF antagonists and can inhibit TNFalpha-mediated proinflammatory effects.

METHODS

Levels of sTNF-RI + II were measured using commercially available enzyme-linked immunosorbent assays (ELISAs). Serum levels of sTNF-RI + II of 76 healthy volunteers were compared to serum levels of 373 clinically well-characterized patients with Crohn's disease (CD) and 118 patients with ulcerative colitis (UC) with different disease activity from the German IBD competence network serum bank. CD patient subgroups were defined according to the Vienna Classification.

RESULTS

The serum levels of sTNF-RI were significantly increased in all groups (active, chronic active, and remission) of CD and UC patients compared to healthy controls. sTNF-RII levels were significantly higher in active CD patients compared to UC patients with no overlap of the 95% confidence interval. Significantly higher values of sTNF-RII compared to controls were also observed in CD patients and UC patients in remission. There was no statistically significant difference in sTNF-RI or sTNF-RII levels when patient subgroups were analyzed according to disease behavior or disease localization.

CONCLUSION

sTNF-RI is upregulated in the serum of IBD patients compared to healthy controls and could be used as a marker for disease activity. sTNF-RII levels are significantly more elevated in serum of active CD patients as compared to UC and could be used as an additional parameter to discriminate both diseases.

Predictors of early response to infliximab in patients with ulcerative colitis

BACKGROUND

Our objective is to report the outcome of infliximab (IFX) in ulcerative colitis (UC) patients from a single center and to identify predictors of early clinical response.

METHODS

The first 100 UC patients (45 female; median age, 37.9 years) who received IFX at a single center were included. Eighty-four patients received 5 mg/kg IFX, and 37 patients received a 3-dose IFX induction at weeks 0, 2, and 6. The Mayo endoscopic subscore, assessed by sigmoidoscopy before inclusion, was 1, 2, and 3 in 5%, 52%, and 43% of patients, respectively. Sixty percent had pancolitis, 63% were on concomitant immunosuppressive therapy, 9% were active smokers, 64% had C-reactive protein > or =5 mg/dL, and 44% were pANCA+/ASCA-. Five patients received IFX because of severe acute colitis refractory to intravenous corticosteroids.

RESULTS

Early complete and partial clinical responses were observed in 41% and 24% of patients. Patients with early clinical response were significantly younger than nonresponders (median age, 35.7 versus 41.6 years, P = 0.041). Patients who were pANCA+/ASCA- had a significantly lower early clinical response (55% versus 76%; odds ratio [OR] = 0.40 (0.16-0.99), P = 0.049). Concomitant immunosuppressive therapy and the use of an IFX induction scheme did not influence early clinical response. Only 1 of 5 patients who received IFX for acute steroid-refractory colitis required colectomy within 2 months.

CONCLUSIONS

IFX is an efficient therapy in UC, as shown by 65% early clinical response. A pANCA+/ASCA- serotype and an older age at first IFX infusion are associated with a suboptimal early clinical response.

Infliximab in ulcerative colitis

Infliximab is effective for treatment of moderate-to-severe UC and is recommended for patients who have had an inadequate response to medical therapy or who are intolerant of or do not desire to take the potential risk of using specific agents including immunomodulators (cyclosporine A, azathioprine, or 6-mercaptopurine), corticosteroids, and, potentially, mesalamine. Future trials are needed to assess the efficacy of infliximab with immunomodulators to see if additional benefit is achieved so that the risk-benefit ratio is positive. Based on the favorable efficacy of infliximab for UC therapy, the ground work has been established for evaluating infliximab and addressing some of the many unanswered questions and also for assessing other anti-TNF agents and streamlining the anti-TNG antibody to improve efficacy, reduce side effects, and ease administration.

Infliximab use in luminal Crohn's disease

Infliximab has been available in the United States and Europe for more than 6 years, and its use has revolutionized the care of patients who have CD. It is used effectively for both the induction and maintenance of remission in patients who have CD and is efficacious in patients who have steroid-dependent/refractory CD and those who have fistulizing CD. Clinical trials and practice have shown infliximab to be safe, effective, and generally well tolerated. The ACCENT I and ACCENT II trials defined the best dosing and schedule regimens for its administration. With up to 30% of patients not responding to infliximab therapy, much attention has been devoted to identifying risk factors that could allow optimization of response rates. Parsi and colleagues and Arnott and colleagues demonstrated that nonsmoking and the concurrent use of immunomodulators are predictors of response to infliximab. Research has also focused on identifying biologic and immunologic markers that may correlate with response to infliximab. To date, N0D2/CARD15, anti-Saccharomyces cerevisiae antibody (ASCA), and antineutrophil cytoplasmic antibody (ANCA) have not been shown to be predictive of outcome with infliximab treatment for CD. Gene polymorphisms also are being studies with the hope that knowing the patient's genotype may help predict the course or severity of the disease, including the presence of extraintestinal manifestations, response to treatments, and susceptibility to toxicities. No single variable, however, has been consistently demonstrated to be a predictor of response to infliximab. The formation of ATIs in a small number of patients creates a clinical dilemma. ATIs have been associated with an attenuated response or loss of response to the medication over time and the development of both acute and delayed infusion reactions that occasionally are severe enough to lead to discontinuation of the medication. In such patients physicians are often left to ponder what therapy to try next. Adalimumab, a fully human monoclonal antibody used for treating rheumatologic conditions, has been investigated as an alternate treatment for patients who have CD who, after initially responding to infliximab, experience intolerance or loss of efficacy. Two studies have examined the use of adalimumab in patients who have active CD who had lost response to or developed intolerance to infliximab. In both these studies adalimumab was well tolerated and seemed to be a clinically beneficial option for such patients. Confirmation of these findings with ongoing randomized, double-blind, placebo-controlled trials is needed, however. The limits of conventional treatment for CD can be seen as a positive evolutionary force favoring the development and use of advanced therapies. The acceptance of antimetabolites began with data published a quarter-century ago and became robust in the past 5 to 10 years. Biologic therapy has become the standard of care at a far faster rate. The success seen with infliximab has broadened the acceptance of biologic therapy among professional peers, patients, and pharmaceutical developers. The lessons learned in the years since infliximab's arrival show the importance of long-term data in revealing important toxicities and best practices for maintenance. Tempered by this experience, the short cycle from concept to drug production possible with biologic therapies should bring even more advanced treatments to patients quickly while investigators work to find a cure.

Dietary apigenin suppresses IgE and inflammatory cytokines production in C57BL/6N mice

Flavonoids ubiquitously exist in plants, vegetables, fruits, and teas. We evaluated the effect of dietary apigenin, one of the well-known flavonoids, on the immune system in C57BL/6N mice. Mice were fed experimental diets containing apigenin for 2 weeks. After the experimental period, there was no significant difference in body and organ weights between the control and the apigenin group. The total immunoglobulin (Ig) E levels in mice fed apigenin were significantly suppressed, whereas levels of IgG, IgM, and IgA were not affected. We also examined the effect of the apigenin diet on cytokine expression in mice sera using a cytokine array. The production of regulated upon activation normal T cell expressed and secreted (RANTES) and soluble tumor necrosis factor receptor I (sTNFRI) in mice sera was down-regulated by the apigenin diet. These results suggest that a diet containing apigenin can reduce serum IgE and inflammatory cytokines such as RANTES and sTNFRI in mice.

Infliximab and ulcerative colitis

Tumour necrosis factor (TNF)-alpha is an inflammatory cytokine that plays a main role in the inflammatory process underlying inflammatory bowel disease (IBD). Despite the fact that the cytokine profiles associated with ulcerative colitis (UC) and Crohn's disease (CD) are classically considered different (a Th2 pattern in UC and a Th1 pattern in CD), there are several evidences in vitro and in vivo that TNF-alpha has an important role in UC. For this reason, infliximab, the chimeric monoclonal antibody to TNF-alpha, has been evaluated in the therapy of UC. The drug has been evaluated in different clinical settings both in adults and in children: in moderate-severe steroid-dependent UC, in severe refractory UC as rescue therapy, in active non-steroid-refractory UC, in resistant pouchitis and in maintenance of moderate-severe UC responsive to infliximab. On the basis of the randomised controlled trials (RCTs), it is possible to draw the following conclusions for adults: infliximab seems active in severe steroid-refractory UC, allowing colectomy to be spared even if further controlled trials are needed with a larger sample of patients adopting strict and well-defined inclusion criteria. The drug seems active in inducing remission after 8 weeks in steroid-refractory patients, in patients taking steroids (even if it is not clear at which dosage of steroid dependence the drug is more active) and also in patients failing aminosalicylates therapy. The long-term response of infliximab in comparison to placebo in these subgroups of patients is not clinically impressive even if it is statistically significant. Further trials are warranted in order to establish the role of infliximab in steroid-dependent UC (defined with clear criteria), in maintaining remission after severe UC, in non-steroid-dependent moderate-severe UC and in refractory pouchitis. For children it is not possible to draw the same conclusions, due to a lack of RCTs, despite the encouraging data coming from open studies, mainly in steroid-refractory UC.

Role of tumor necrosis factor receptors in an animal model of acute colitis

TNF-alpha is known to play an important role in inflammatory bowel disease (IBD); however, the pathophysiological role of its receptors is still under study. Acute colitis was induced in rats by intracolonic administration of trinitrobenzene sulfonic acid (TNBS). Control rats received the ethanol vehicle. Rats were sacrificed 72 h later and samples of tissue and fluids were collected. There was a significant increase in the protein levels of sTNF-alpha, sTNFRI, and sTNFRII in the peritoneal fluid (PF) of experimental rats. TNF-alpha, TNFRI, and TNFRII mRNA expression was increased significantly in the colon of experimental animals compared to controls. TRAF3 and TRAF5 expression was also significantly higher, as was that of the adhesion molecules ICAM-1 and E-selectin. The increased expression of TNF-alpha, TNFRs, and the associated signaling factors in the colon of this rat model of IBD provides further evidence for their involvement in the promotion of inflammation and tissue damage. In addition, increased levels of sTNFRs in the PF of experimental rats--particularly sTNFRII--may be involved in the development of colitis by serving as a reservoir of TNF-alpha, and thus provide a novel therapeutic target for IBD.

Clinical Assessment of Disease Activity for Canine Inflammatory Bowel Disease

Clinical indices, consisting of gastrointestinal signs and laboratory parameters, are widely used for assessing disease activity in human inflammatory bowel disease (IBD). The development of a standardized scoring index for use in dogs with IBD would be useful in the management of clinical cases, both at diagnosis and in response to medical therapy. This review provides a synopsis of current strategies used to assess IBD activity in humans and companion animals. The clinical application of a simple scoring index (e.g., canine IBD activity index [CIBDAI]) for measurement of canine IBD activity is also reviewed.

Soluble tumor necrosis factor (TNF) receptor-1 induces apoptosis via reverse TNF signaling and autocrine transforming growth factor-beta1

The pro-inflammatory cytokine tumor necrosis factor-alpha (TNF-alpha) plays a central role in inflammatory disorders. Transmembrane TNF-alpha and its two receptors are cleaved by the proteinase TNF-alpha converting enzyme (TACE), resulting in appreciable serum levels of soluble TNF-alpha and soluble TNF-alpha receptors (sTNFR1 and -2). The only known functions of sTNFR1 are to antagonize and buffer circulating TNF-alpha. Here, we present evidence that sTNFR1 exerts immunoregulatory functions by induction of apoptosis in monocytes through reverse signaling via transmembrane TNF-alpha. sTNFR1-induced apoptosis is independent of death receptor pathways but depends on autocrine transforming growth factor (TGF)-beta1 signaling through the mitogen-activated protein kinase p38alpha. This novel mechanism has implications for understanding the physiological role of sTNFR1 and for TNF-alpha-blocking therapies of autoimmune diseases.

Current therapeutic recommendations: infliximab for ulcerative colitis

Randomized, controlled studies have shown that infliximab, the chimeric anti-tumor necrosis factor alpha (TNF-alpha) antibody, is effective for the treatment of active and fistulizing Crohn's disease. Because infliximab is beneficial in patients with Crohn's disease, in whom other therapies have failed, it has been postulated that infliximab may also be helpful in patients with ulcerative colitis. Many investigators have studied the effectiveness of infliximab in ulcerative colitis, mainly in patients who are refractory to corticosteroids. Unfortunately, these studies have not yielded a conclusive answer to the efficacy of infliximab in inducing remission in patients with severe ulcerative colitis. However, some have reported excellent results and others less effective, with the overall data being inconclusive. The purpose of this review is to summarize the current literature on the use of infliximab in ulcerative colitis, as well as to provide insight into the possible mechanisms of why it may or may not work in these difficult-to-treat patients.

No dose-dependent tubulotoxicity of 5-aminosalicylic acid: a prospective study in patients with inflammatory bowel diseases

BACKGROUND AND AIMS

Elevated levels of renal tubular markers in the urine are found in 20-30% of patients with chronic inflammatory bowel diseases. We investigated whether this reflects a dose-dependent tubulotoxicity of 5-aminosalicylic acid (5-ASA).

PATIENTS AND METHODS

In an open, prospective, multicenter study 18 patients with Crohn's disease and 29 with ulcerative colitis were treated with 3 g 5-ASA or more daily as the sole drug for 6 weeks. Clinical activity (CDAI, CAI) and renal tubular markers [beta-N-acetyl-D-glucosaminidase (beta-NAG) and other proteins in urine] were monitored. We examined whether the proportion of patients with elevated beta-NAG is more than 15% higher (absolute difference) than that prior to treatment.

RESULTS

The proportion decreased from 19.2% to 12.8% in the intention-to-treat analysis (n=47) and from 24.3% to 13.5% in the per-protocol analysis (n=37), which was not more than 15% higher than at baseline. Mean CDAI decreased from 222 to 146 and mean CAI from 7.3 to 3.1 (intention-to-treat analysis). Response to therapy was shown by 61% of patients with Crohn's disease and 66% of patients with ulcerative colitis. The cumulative dose of 5-ASA was not correlated with beta-NAG level in the urine.

CONCLUSION

This study largely rules out that 5-ASA at 3 g or higher per day for 6 weeks induces renal tubular damage. Elevated renal tubular markers reflect inflammatory activity or an extraintestinal manifestation of inflammatory bowel diseases.

A scoring index for disease activity in canine inflammatory bowel disease

The clinical course of inflammatory bowel disease (IBD) in dogs is characterized by spontaneous exacerbations and remissions, which makes assessment of disease burden difficult. The objectives of this study were to develop a scoring system for evaluation of canine IBD activity and to validate this scoring method by correlating it to objective laboratory and histologic indices of intestinal inflammation. Fifty-eight dogs with IBD were evaluated prospectively and compared to 9 disease-free control dogs. Clinical disease activity was quantified by a simple scoring system, the canine IBD activity index (CIBDAI), and compared to serum concentrations of C-reactive protein (CRP), haptoglobin (HAP), alpha-acid glycoprotein (AGP), and serum amyloid A (SAA), as well as histology scores derived from endoscopic biopsy specimens. Forty-six dogs were available for a reevaluation of the CIBDAI, CRP HAP, and AGP, and 34 dogs had repeat analysis of SAA performed after medical therapy. Serum concentrations of CRP were significantly (P < .02) increased in dogs with CIBDAI scores > or = 5 (mild disease activity or greater) compared to controls. Among IBD dogs, the CIBDAI showed good correlation (r = 0.82, P < .0001) to both histology and HAP scores, but CRP also was a strong co-correlate of disease activity. The IBD dogs showed significantly (P < .0001) decreased CIBDAI and CRP values but significantly (P < .0001) increased HAP concentrations after medical therapy compared to pretreatment values. We conclude that the CIBDAI is a reliable measure of inflammatory activity in canine IBD and that CRP is suitable for laboratory evaluation of the effect of therapy in these patients.

The effect of lower limb ischaemia-reperfusion on intestinal permeability and the systemic inflammatory response

OBJECTIVES

a relationship has been demonstrated between increased intestinal permeability, endotoxaemia and the development of the systemic inflammatory response syndrome (SIRS) after aortic surgery. The aim of this study was to evaluate whether isolated lower limb ischaemia-reperfusion (I/R) injury affects intestinal mucosal barrier function and cytokine release.

PATIENTS AND METHODS

four groups of patients were investigated, group I, patients with critical limb ischaemia (CLI) undergoing infra-inguinal bypass surgery (n=18); group II, patients with intermittent claudication (IC) undergoing infra-inguinal bypass surgery (n=14); group III, patients with CLI unsuitable for arterial reconstruction, undergoing major amputation (n=12); and group IV, patients undergoing carotid endarterectomy for symptomatic carotid stenosis (n=13). Intestinal permeability, endotoxaemia and urinary soluble tumour necrosis factor receptors were assessed (p55TNF-R).

RESULTS

an increase in intestinal permeability was observed on the 3rd postoperative day only in CLI group. This was found to correlate with arterial clamp time. Patients who had a femoro-distal bypass had significantly higher intestinal permeability compared to those who had femoro-popliteal bypass. Endotoxaemia was not detected in any of the groups. Postoperative urinary p55TNF-R concentrations were significantly higher in CLI group compared to the other groups. These did not correlate with the increased intestinal permeability.

CONCLUSIONS

our results support the hypothesis that revascularisation of critically ischaemia limbs leads to intestinal mucosal barrier dysfunction and cytokine release. They also suggest that the magnitude of the inflammatory response following I/R injury is related to the degree of initial ischaemia.

Cytokine activation and intestinal mucosal and renal dysfunction are reduced in endovascular AAA repair compared to surgery

PURPOSE

To compare endovascular (EVR) to open repair (OR) of abdominal aortic aneurysm (AAA) for cytokine activation, changes in the intestinal mucosal barrier, and renal dysfunction.

METHODS

In a prospective nonrandomized study, 15 patients admitted to a university hospital for elective infrarenal AAA repair (8 OR and 7 EVR) were recruited. Intestinal permeability was assessed preoperatively (PO), at day 1 (D1), and at day 3 (D3) after surgery using the lactulose/mannitol differential excretion (LMR) test. Renal damage was assessed from measurements of the urinary albumin:creatinine ratio (ACR); cytokine activation was based on the urinary concentration of tumor necrosis factor receptor p55 (TNF-Rp55) at the same time points. Serum creatinine and urea concentrations were measured preoperatively and daily for 5 days postoperatively.

RESULTS

A significant increase in LMR was found in the OR group at D1 and D3 compared to PO (p<0.05). The LMR increase at D3 was significantly greater in the OR group (p<0.01). A significant difference was observed in the percentage rise in ACR on D1 in the OR group compared to the EVR group (p<0.005). The urinary TNF-Rp55 concentration was significantly elevated in the OR group at D1 (p<0.05) and D3 (p<0.05) compared to baseline; in the EVR group, it was elevated at D1 (p<0.05) compared to PO. The difference was also significant for this marker between the 2 groups at D1 (p<0.01). No significant change was observed in the serum creatinine or urea concentrations in either group perioperatively.

CONCLUSIONS

Endovascular AAA repair is associated with less cytokine production and less intestinal and renal dysfunction compared to the open approach.

Infliximab for treatment of steroid-refractory ulcerative colitis

BACKGROUND

Success achieved in two subtypes of Crohn's disease has persuaded a few investigators to experiment the monoclonal anti-tumour necrosis factor antibody infliximab in the treatment of ulcerative colitis. So far, however, the results (achieved in some 30 steroid-refractory patients included in two independent full-papers) indicate a rate of initial response of 50% and of remission of 25%.

AIMS

To analyse data of an open trial conducted on consecutive steroid-refractory severely ill patients admitted to our referral Unit.

PATIENTS AND METHODS

In 9 months, infliximab was given to 8 patients (4 male, 4 female aged 20-60 years) with uncontrolled ulcerative colitis of whom 6 were non-responders to parenteral steroids. All received the first infliximab dose as an intravenous infusion of 5 mg/kg.

RESULTS

Of the 8, 4 (50%) did not respond to the first injection and were submitted to urgent colectomy; the other four responded clinically. Two have maintained clinical remission for 7 months, without the need for steroids; both have received daily azathioprine at 2 mg/kg, and only one has received two further infliximab injections. Of the other two, one received a second injection at week 5, despite this relapsed, and underwent elective colectomy at that time; the other relapsed at 6 months and showed a partial response to a repeat infliximab infusion. Thus, the rate of sustained response is 2/8 (25%) in this study.

CONCLUSION

These results, achieved in an open uncontrolled fashion, seem to reflect those of other independent studies. In our opinion, these findings warrant an in-depth reappraisal of the indication to use infliximab as rescue treatment for refractory ulcerative colitis.

Integrating anti-tumor necrosis factor therapy in inflammatory bowel disease: current and future perspectives

Crohn's disease and ulcerative colitis are two idiopathic inflammatory disorders of the GI tract. Manifestations of disease can be severe and lead to long term therapy with a variety of medications and/or surgery. Standard medical therapy consists of agents that either treat suppurative complications or modulate the inflammatory cascade in a nonspecific manner. Many specific chemokine and cytokine effectors that promote intestinal inflammation have been identified. Such work has led to experimental clinical trials with a variety of cytokine antagonists. Compounds directed against one such cytokine, tumor necrosis factor alpha (TNF), have demonstrated the greatest clinical efficacy to date. This is consistent with scientific observations that suggest a central role for TNF in the inflammatory cascade. Infliximab is a chimeric monoclonal antibody against TNF that has been demonstrated to be effective for the treatment of Crohn's disease. Infliximab is Food and Drug Administration approved for the treatment of Crohn's disease. There exist several other TNF antagonists in various phases of investigation, including the monoclonal antibody CDP 571, the fusion peptide etanercept, the phosphodiesterase inhibitor oxpentifylline, and thalidomide. The clinical efficacy of these agents and the role of TNF in the pathogenesis of inflammatory bowel disease is reviewed.

Established and emerging biological activity markers of inflammatory bowel disease

Assessment of disease activity in inflammatory bowel disease (IBD), i.e., ulcerative colitis (UC) and Crohn's disease (CD), is done using clinical parameters and various biological disease markers. Ideally, a disease marker must: be able to identify individuals at risk of a given disorder, be disease specific, mirror the disease activity and, finally, be easily applicable for routine clinical purposes. However, no such disease markers have yet been identified for IBD. In this article, classical disease markers including erythrocyte sedimentation rate, acute phase proteins (especially orosomucoid and CRP), leukocyte and platelet counts, albumin, neopterin, and beta2-microglobulin will be reviewed together with emerging disease markers such as antibodies of the ANCA/ASCA type, cytokines (e.g., IL-1, IL-2Ralpha, IL-6, IL-8, TNF-alpha, and TNF-alpha receptors) and with various adhesion molecules. It is concluded that none of the pertinent laboratory surrogate markers of disease activity in IBD are specific or sensitive enough to replace basic clinical observation such as the number of daily bowel movements, general well-being, and other parameters in parallel. Further studies are highly warranted to identify and assess the clinical importance and applicability of new laboratory markers for the diagnosis or the disease activity of IBD.