Irritable bowel syndrome and active inflammatory bowel disease diagnosed by faecal gas analysis.

BACKGROUND: Inflammatory bowel disease and irritable bowel syndrome may present in a similar manner. Measuring faecal calprotectin concentration is often recommended to rule out inflammatory bowel disease, however, there are no tests to positively diagnose irritable bowel syndrome and invasive tests are still used to rule out other pathologies. AIM: To investigate a platform technology for diagnosing inflammatory bowel disease and irritable bowel syndrome based on faecal gas. METHODS: The platform technology is composed of a gas chromatography column coupled to a metal oxide gas sensor (OdoReader) and a computer algorithm. The OdoReader separates the volatile compounds from faecal gas and the computer algorithm identifies resistance patterns associated with specific medical conditions and builds classification models. This platform was applied to faecal samples from 152 patients: 33 patients with active inflammatory bowel disease; 50 patients with inactive inflammatory bowel disease; 28 patients with irritable bowel syndrome and 41 healthy donors (Control). RESULTS: The platform classified samples with accuracies from 75% to 100% using rigorous validation schemes: namely leave-one-out cross-validation, 10-fold cross-validation, double cross-validation and their Monte Carlo variations. The most clinically important findings, after double cross-validation, were the accuracy of active Crohn's disease vs. irritable bowel syndrome (87%; CI 84-89%) and irritable bowel syndrome vs. controls (78%; CI 76-80%). These schemes provide an estimate of out-of-sample predictive accuracy for similar populations. CONCLUSIONS: This is the first description of an investigation for the positive diagnosis of irritable bowel syndrome, and for diagnosing inflammatory bowel disease.

Towards point of care testing for C. difficile infection by volatile profiling, using the combination of a short multi-capillary gas chromatography column with metal oxide sensor detection.

Rapid volatile profiling of stool sample headspace was achieved using a combination of short multi-capillary chromatography column (SMCC), highly sensitive heated metal oxide semiconductor (MOS) sensor and artificial neural network (ANN) software. For direct analysis of biological samples this prototype offers alternatives to conventional GC detectors and electronic nose technology. The performance was compared to an identical instrument incorporating a long single capillary column (LSCC). The ability of the prototypes to separate complex mixtures was assessed using gas standards and homogenised in house 'standard' stool samples, with both capable of detecting more than 24 peaks per sample. The elution time was considerably faster with the SMCC resulting in a run time of 10 minutes compared to 30 minutes for the LSCC. The diagnostic potential of the prototypes was assessed using 50 C. difficile positive and 50 negative samples. The prototypes demonstrated similar capability of discriminating between positive and negative samples with sensitivity and specificity of 85% and 80% respectively. C. difficile is an important cause of hospital acquired diarrhoea, with significant morbidity and mortality around the world. A device capable of rapidly diagnosing the disease at the point of care would reduce cases, deaths and financial burden.

Volatiles from oral anaerobes confounding breath biomarker discovery.

The levels of compounds in exhaled mouth air do not necessarily reflect levels in the systemic circulation as bacteria can bio-transform substrates to produce compounds within the mouth. This should be of concern to researchers measuring breath volatiles with the aim of diagnosing systemic or metabolic conditions as very little is known about the origin of many compounds detected on the breath. This pilot study investigated the production of volatile compounds by bacterial communities present within the mouth. Solid-phase micro-extraction was used to extract volatiles from the headspace gas of two Gram-positive and two Gram-negative bacterial cultures known to be present within the mouth and from tongue biofilm microflora. Analyses were undertaken using gas chromatography mass spectrometry. Between 64 and 82 volatile compounds were detected from sampling the headspace gas above each of the cultures. Gram-negative anaerobes were found to produce more volatile sulfur compounds (VSCs) and amines. Solobacterium moorei, a Gram-positive species was however found to produce higher levels of acids, hydrocarbons, alcohols and aldehydes than the other species studied. Tongue-scrape biofilm systems at lower pH gave more hydrocarbons, ketones and fatty acids whilst at higher pH more alcohols, aldehydes, VSCs and amines were detected in the headspace. The results show that a number of compounds detected in mouth breath are produced by anaerobic bacteria in tongue biofilms. Thus, the contribution of volatiles from oral anaerobes cannot be ignored and more research is required to identify the major source of breath compounds as this will help determine their clinical significance as indicators of systemic disease or metabolic disorders in the body.

Use of risedronate to prevent bone loss following a single course of glucocorticoids: findings from a proof-of-concept study in inflammatory bowel disease.

SUMMARY: We performed a randomised controlled trial (RCT) to determine whether risedronate 35 mg once weekly prevents bone loss following an 8-week reducing course of prednisolone given for an exacerbation of inflammatory bowel disease (IBD). The greatest change in bone mineral density (BMD) was at Ward's triangle (WT), which fell by 2.2% in the placebo group, compared with a reduction of 0.8% in the risedronate group. INTRODUCTION: Whether bisphosphonates can prevent bone loss associated with intermittent glucocorticoid (GC) therapy is unknown, reflecting the difficulty in performing RCTs in this context. METHOD: To explore the feasibility of RCTs to examine this question, lumbar spine (LS; L2-4) and hip dual X-ray absorptiometry (DXA) scans were performed in 78 patients commencing a GC therapy course for a relapse of IBD. They were then randomised to receive placebo or risedronate 35 mg weekly for 8 weeks, after which the DXA scan was repeated. RESULTS: For LS BMD, there was no change in the placebo group (0.1 +/- 0.4, p = 0.9), but there was an increase after risedronate (0.8 +/- 0.4, p = 0.04; mean% +/- SEM by paired Student's t test). There were small decreases in both groups at the total hip (-0.5 +/- 0.3, p = 0.04; -0.5 +/- 0.3, p < 0.05, placebo and risedronate, respectively). At WT, BMD fell after placebo (-2.2 +/- 0.5, p = 0.001) but not risedronate (-0.8 +/- 0.5, p = 0.09; p = 0.05 for between-group comparison). CONCLUSION: RCTs can be used to examine whether bisphosphonates prevent bone loss associated with intermittent GC therapy, providing metabolically active sites such as WT are employed as the primary outcome.

A pilot study of faecal volatile organic compounds in faeces from cholera patients in Bangladesh to determine their utility in disease diagnosis.

The aim of this pilot study was to analyse the volatile organic compounds in faecal samples collected from cholera patients in Bangladesh to determine biomarkers that could be used for disease diagnosis. Samples were collected from patients at the International Centre for Diarrhoeal Disease Research, Dhaka, Bangladesh and also from healthy controls at the same institution. The volatile organic compounds were extracted from the headspace above the sample using solid phase microextraction and analysed using gas chromatography-mass spectrometry. A biomarker was identified in the cholera samples that could be used for disease diagnosis.

An analysis of volatiles in the headspace of the faeces of neonates.

A gas chromatography/mass spectrometry (GCMS) analysis of the headspace from the faeces of neonates was undertaken to record the volatiles associated with preterm babies on a neonatal unit. The compounds ethanol, acetone, 2-ethyl-1-hexanol, 3-methylbutanal, hexanal and 2,3-butanedione occurred with the highest frequency. The volatiles analysed were then compared to a previously published study of the volatiles from asymptomatic adult faeces. Fewer compounds were found in the neonatal faeces and virtually no sulfides were detected, in contrast to the adult samples where carbon disulfide, dimethyl disulfide and dimethyl sulfide were ubiquitous. In addition, 7 of the most abundant 15 volatile compounds were found to be aldehydes, while in contrast only 2, acetaldehyde and benzaldehyde, were present in the most abundant 15 compounds found in the headspace of adult faeces. 2-Ethyl-1-hexanol was considerably more abundant in the neonate stool compared to adult stool, and probably reflects high exposure to plastic materials containing plasticizers. The potential of disease diagnoses from the analysis of volatiles emitted from neonate faeces is discussed.

A randomized, double-blind, placebo-controlled trial of lenalidomide in the treatment of moderately severe active Crohn's disease.

BACKGROUND: Therapy targeted at tumour necrosis factor-alpha has an established role in Crohn's disease. Lenalidomide, an analogue of thalidomide, is an oral immunomodulatory agent with powerful antitumour necrosis factor-alpha properties. It is licensed for myeloma and myelodysplastic syndrome. Based upon reports of thalidomide efficacy, lenalidomide was evaluated in Crohn's disease. AIM: To evaluate the efficacy and safety of lenalidomide in subjects with moderately severe active Crohn's disease. METHODS: In a multicentre, double-blind, placebo-controlled parallel group study 89 subjects were randomized to lenalidomide 25 mg daily, 5 mg daily or placebo. Subjects were treated for 12 weeks. The primary end point was a 70-point reduction in Crohn's Disease Activity Index. RESULTS: The overall clinical response rate was not significantly different between the three groups: lenalidomide 25 mg 26%, lenalidomide 5 mg 48% and placebo 39%. Lenalidomide was generally well tolerated with only one serious adverse event, a deep vein thrombosis, being attributed to treatment. CONCLUSION: Lenalidomide, an oral agent with antitumour necrosis factor-alpha properties, was not effective in active Crohn's disease in contrast to reports of benefit from thalidomide. The reasons for this lack of efficacy are speculative, other physiological activities may offset its action on inflammatory cytokines, or its antitumour necrosis factor-alpha action without apoptosis may be insufficient for activity in Crohn's disease.

Review article: steroid resistance in inflammatory bowel disease - mechanisms and therapeutic strategies.

BACKGROUND: Steroid resistance in inflammatory bowel disease presents a difficult clinical challenge. The advent of biological therapies coupled with an increasing understanding of the pathogenesis of inflammatory bowel disease has provided new therapeutic options. METHODS: We review the available literature of the mechanisms behind steroid resistance. In addition, we outline some of the options available for treating those patients who fail to respond adequately to glucocorticoids. RESULTS: Approximately 30% of patients prescribed glucocorticoids will not achieve clinical remission. Many such patients are offered immunosuppressive or, recently, biological agents. However, these agents are ineffective in a large proportion of patients. Immunosuppressive agents only bring 40-60% of patients into remission, and biological agents typically induce remission in just 40% of patients. In this review, the possible explanations for glucocorticoid resistance are discussed. Recent evidence suggests that in many patients it is mediated by interleukin-2. Basiliximab, a biological agent that interrupts interleukin-2 signalling, has shown significant benefit in early clinical studies. CONCLUSIONS: Patients who fail to respond to steroid therapy should have alternative agents introduced in a timely fashion. Steroid refractory inflammatory bowel disease remains a difficult condition to treat, but new therapies and managements are emerging.

Basiliximab for the treatment of steroid-resistant ulcerative colitis: further experience in moderate and severe disease.

BACKGROUND: Preliminary data have suggested that interleukin-2 receptor blockade with basiliximab may increase steroid sensitivity. We have previously reported a small case series demonstrating the potential of basiliximab as a novel agent for the treatment of steroid-resistant ulcerative colitis. AIM: To report further experience of the efficacy and safety of treatment with the interleukin-2 receptor blocking monoclonal antibody basiliximab, in addition to steroids, for the treatment of severe and moderate steroid-resistant ulcerative colitis. METHODS: Twenty patients were enrolled - 13 patients with moderate steroid-resistant ulcerative colitis (Ulcerative Colitis Symptom Score: >or=6) and seven patients with severe steroid-resistant ulcerative colitis. All were given a single dose of 40 mg basiliximab plus standard steroid therapy in an open-label, uncontrolled trial. Primary end point was clinical remission within 8 weeks (Ulcerative Colitis Symptom Score:

Rapid hip bone loss in active Crohn's disease patients receiving short-term corticosteroid therapy.

BACKGROUND: Uncertainty over whether corticosteroids cause bone loss in patients with Crohn's disease may reflect their short, intermittent use. AIM: We investigated whether a 2-month course of prednisolone is associated with detectable bone loss. METHODS: Fifteen patients with active Crohn's disease and 19 controls with inactive Crohn's disease were recruited. Bone mineral density of the lumbar spine and hip was measured at baseline and 2 and 8 months. RESULTS: At 2 months, significant bone loss was found in patients with active disease (femoral neck -2.7%, P < 0.002; Ward's triangle -3.9%, P < 0.01). Although bone mineral density was still lower at 8 months, these differences were no longer significant (-1.3% and -3.4%, femoral neck and Ward's triangle, respectively). No significant change in hip bone mineral density was observed in controls. Previous corticosteroid use was not significantly associated with baseline bone mineral density, although significant independent associations were observed between weight, site of disease and lumbar spine bone mineral density, and between dietary calcium deficiency and femoral neck and Ward's triangle bone mineral density. CONCLUSION: Significant bone loss at the hip can be detected in patients receiving corticosteroid treatment for 2 months for active Crohn's disease ; however, it remains unclear whether this is because of disease activity or its treatment. This rapid bone loss may represent a risk factor for fracture and justify bone protective therapy.

A novel method for rapidly diagnosing the causes of diarrhoea.

BACKGROUND: The microbiological diagnosis of infectious diarrhoea may take several days using conventional techniques. In order to determine whether flatus can be used to make a rapid diagnosis, the volatile organic compounds associated with diarrhoea were analysed. METHODS: Stool samples were collected from 35 patients with infectious diarrhoea and from six healthy controls. Gaseous compounds were extracted from a headspace using solid phase microextraction and analysed using gas chromatography and mass spectroscopy. RESULTS: Characteristic patterns of volatile gases were found for the main causes of infectious diarrhoea in hospitals. Furan species without indoles indicated Clostridium difficile, ethyl dodecanoate indicated rotavirus, ammonia without ethyl dodecanoate suggested other enteric viruses, and the absence of hydrocarbons and terpenes indicated Campylobacter infection. CONCLUSION: These results could be the basis of rapid near patient diagnosis of infectious diarrhoea.

Basiliximab (anti-CD25) in combination with steroids may be an effective new treatment for steroid-resistant ulcerative colitis.

BACKGROUND: Steroid resistance represents a major clinical problem in the treatment of ulcerative colitis. In vitro, interleukin-2 renders lymphocytes steroid resistant. AIM: To explore the therapeutic potential of interleukin-2 receptor blockade in steroid-resistant ulcerative colitis with both in vitro measures and a pilot in vivo study. METHODS: Ten patients with steroid-resistant ulcerative colitis received a single bolus of 40 mg of intravenous basiliximab plus steroid treatment in an open-label, uncontrolled, 24-week study. The outcome was assessed using the Ulcerative Colitis Symptom Score, rectal biopsy and Inflammatory Bowel Disease Questionnaire. Lymphocyte steroid sensitivity was measured in vitro in 39 subjects in the presence or absence of basiliximab. RESULTS: Nine of the 10 patients achieved clinical remission within 8 weeks. At 24 weeks, seven patients were in clinical remission. Marked improvement in the Ulcerative Colitis Symptom Score was seen by 1 week (P = 0.004) and on rectal biopsy and Inflammatory Bowel Disease Questionnaire by 2 weeks (both P < 0.05). Improvements persisted to 24 weeks (Ulcerative Colitis Symptom Score, Inflammatory Bowel Disease Questionnaire, both P < 0.005). Eight of the nine responders relapsed (median, 9 weeks), but remission was re-achieved with further corticosteroids and the addition of azathioprine. At 24 weeks, seven patients were in full clinical remission, five off all steroid therapy. In vitro measurement of lymphocyte steroid sensitivity demonstrated steroid resistance in 22% of subjects. All were rendered steroid sensitive in the presence of basiliximab. CONCLUSIONS: Basiliximab appears to be effective at inducing remission in steroid-resistant ulcerative colitis. In vitro, basiliximab also produced a dramatic increase in lymphocyte steroid sensitivity in healthy subjects. Confirmation in randomized controlled studies is required.

Infliximab in moderately severe glucocorticoid resistant ulcerative colitis: a randomised controlled trial.

BACKGROUND: Tumour necrosis factor production is increased in the mucosa of patients with active ulcerative colitis. The benefits of infliximab in Crohn's disease are established. We investigated its efficacy in ulcerative colitis. METHODS: We conducted a randomised placebo controlled trial of infliximab (5 mg/kg) in the treatment of glucocorticoid resistant ulcerative colitis. Infusions were given at weeks 0 and 2. Disease activity and quality of life were recorded over eight weeks of follow up. Remission was defined as an ulcerative colitis symptom score (UCSS) of < or =2 and/or Baron score of 0 at week 6. Patients not in remission were offered open label infliximab 10 mg/kg and reviewed two weeks later. RESULTS: After two weeks, there was no statistically significant difference between the infliximab and placebo groups in the proportion of patients with a Baron score of 0 (13% (3/23) v 5% (1/19) (95% confidence interval (CI) -9% to 24%); p=0.74). After six weeks, remission (UCSS < or =2) rates were 39% (9/23) versus 30% (6/20) (95% CI -19 to 34%; p=0.76). The median improvement in UCSS was 3 for the infliximab group and 2.5 for the placebo group (p=0.82, Mann-Whitney U test). A Baron score of 0 was likely in either group (26% (6/23) v 30% (6/20) (95% CI -30% to 23%); p=0.96). Improvement in the IBDQ and EuroQol was not significantly different between the groups (p=0.22 and 0.3, respectively, Mann-Whitney U test). Twenty eligible patients were given open labelled infusions. Remission was achieved in 3/11 (27%) patients initially treated with infliximab and in 1/9 (11%) patients treated with placebo. CONCLUSION: These data do not support the use of infliximab in the management of moderately active glucocorticoid resistant ulcerative colitis.

Refeeding syndrome: effective and safe treatment with Phosphates Polyfusor.

BACKGROUND: Severe hypophosphataemia associated with refeeding syndrome requires treatment with intravenous phosphate to prevent potentially life-threatening complications. However, evidence for replacement regimens is limited and current regimens are complex and replace phosphate inadequately. AIM: To assess the effectiveness and safety of 50 mmol intravenous phosphate infusion, given as a 'Phosphates Polyfusor', for the treatment of severe hypophosphataemia in refeeding syndrome. METHODS: Patients with refeeding syndrome and normal renal function received a Phosphates Polyfusor infusion for the treatment of severe hypophosphataemia (< 0.50 mmol/L). The outcome measures were serial serum phosphate, creatinine and calcium concentrations for 4 days following phosphate infusion and adverse events. RESULTS: Over 2 years, 30 patients were treated. Following treatment, 37% of cases had a normal serum phosphate concentration and 73% had a serum phosphate concentration of > 0.5 mmol/L within 24 h. Ten patients required more than one Phosphates Polyfusor infusion. Within 72 h, 93% of cases had achieved a serum phosphate concentration of > or = 0.50 mmol/L. No patient developed renal failure. Three episodes of transient mild hyperphosphataemia were recorded. Four patients developed mild hypocalcaemia. CONCLUSIONS: This is the largest published series of the use of intravenous phosphate for the treatment of severe hypophosphataemia (< 0.50 mmol/L), and is the most effective regimen described. All patients had refeeding syndrome and were managed on general wards.

Is your patient taking the medicine? A simple assay to measure compliance with 5-aminosalicylic acid-containing compounds.

BACKGROUND: Poor compliance with 5-aminosalicylic acid therapy has been reported amongst patients with inflammatory bowel disease. Currently, there is no easy method to monitor 5-aminosalicylic acid; however, the chemical similarity between 5-aminosalicylic acid and salicylate might provide a solution. AIM: To determine the feasibility of using salicylate levels to monitor compliance with 5-aminosalicylic acid medication. METHODS: Thirty-six patients with inflammatory bowel disease, taking maintenance 5-aminosalicylic acid, provided either a paired serum and urine sample or an intestinal biopsy. Samples were split into two: half were sent to the hospital biochemistry department for salicylate measurement, and half were analysed for 5-aminosalicylic acid and its metabolite, N-acetyl-5-aminosalicylic acid, using high performance liquid chromatography. Correlation between the results was calculated. RESULTS: Serum and urine were available for 25 patients. Serum salicylate was undetectable, but urinary salicylate ranged from 31 to 3254 microg/mL. The correlations between urinary salicylate and 5-aminosalicylic acid and N-acetyl-5-aminosalicylic acid were 0.96 (95% confidence interval, 0.91-0.98) and 0.9 (95% confidence interval, 0.77-0.96), respectively. Sixteen biopsies were available from 13 patients. The 5-aminosalicylic acid and N-acetyl-5-aminosalicylic acid concentrations were 0.2-657 ng/mg and 1.6-1598 ng/mg, respectively; there was no correlation with bowel salicylate. CONCLUSIONS: The close correlation between 5-aminosalicylic acid and salicylate levels offers a simple method to assess compliance with 5-aminosalicylic acid therapy.