Gut lavage fluid proteins as markers of activity of inflammatory bowel disease

The biophysical principles underpinning muco-trapping functions of antibodies

In addition to the classical immunological functions such as neutralization, antibody-dependent cellular cytotoxicity, and complement activation, IgG antibodies possess a little-recognized and under-utilized effector function at mucosal surfaces: trapping pathogens in mucus. IgG can potently immobilize pathogens that otherwise readily diffuse or actively swim through mucus by forming multiple low-affinity bonds between the array of pathogen-bound antibodies and the mucin mesh. Trapping in mucus can exclude pathogens from contacting target cells, and facilitate their rapid elimination by natural mucus clearance mechanisms. Despite the fact that most infections are transmitted at mucosal surfaces, this muco-trapping effector function has only been revealed within the past decade, with the evidence to date suggesting that it is a universal effector function of IgG-Fc capable of immobilizing both viral and highly motile bacterial pathogens in all major mucosal secretions. This review provides an overview of the current evidence for Fc-mucin crosslinking as an effector function for antibodies in mucus, the mechanism by which the accumulation of weak Fc-mucin bonds by IgG bound to the surface of a pathogen can result in immobilization of antibody-pathogen complexes, and how trapping in mucus can contribute to protection against foreign pathogens.

Dietary ω-6/ω-3 Polyunsaturated Fatty Acid Ratios Affect the Homeostasis of Th/Treg Cells in Mice With Dextran Sulfate Sodium-Induced Colitis

BACKGROUND

This study evaluated the effect of different dietary ω-6/ω-3 polyunsaturated fatty acid (PUFA) ratios on modulating helper T (Th) and regulatory T (Treg) lymphocytes in mice with dextran sulfate sodium (DSS)-induced colitis.

METHODS

There were 3 control and 3 colitis groups. Mice were fed for 24 days with diets with soybean oil (S), a mixture of soybean oil and low fish oil content (LF), or high fish oil content (HF). The ratio of ω-6/ω-3 PUFA in the LF diet was 4:1, and that in the HF diet was 2:1. The control groups drank distilled water while colitis groups were provided 2% DSS in drinking water during days 15-19. All mice drank distilled water from days 20-24 for recovery and were sacrificed on day 25.

RESULTS

Colitis resulted in higher blood Th1, Th2, and Th17 and lower Treg percentages. Also, plasma haptoglobin and proinflammatory chemokines were elevated in colon lavage fluid. Colitic groups with fish oil had lower inflammatory mediators in the plasma and colon lavage fluid. Furthermore, the percentages of blood Th1, Th2, and Th17 cells were lower, whereas Treg cell percentages were higher than those in the soybean oil group. The colitis group with an ω-6/ω-3 PUFA ratio of 2:1 had more pronounced effects than the group with a ratio of 4:1.

CONCLUSIONS

Diets with an ω-6/ω-3 PUFA ratio of 2:1 or 4:1 regulate the Th/Treg balance and attenuate inflammatory mediator production in colitis. Compared with the ω-6/ω-3 PUFA ratio of 4:1, the ratio of 2:1 was more effective in reducing inflammatory reactions in DSS-induced colitis.

Review article: biological activity markers in inflammatory bowel disease

BACKGROUND

Traditionally, inflammatory bowel disease activity is assessed by clinical activity indices that measure clinical symptoms and endoscopic indices that measure endoscopic inflammation. Biological markers are a non-invasive way of objectively measuring inflammation and can play an adjunctive or primary role in the assessment of disease activity.

AIM

To review the data on biological markers for assessment of disease activity and prediction of relapse in inflammatory bowel disease.

METHODS

To collect relevant articles, a PubMed search was performed from 1980 to 2006 using following search terms in combination: inflammatory bowel disease, biomarkers, inflammation, disease activity, relapse, acute phase reactants cytokines, interleukins, adhesion molecules, integrins, calprotectin and lactoferrin.

RESULTS

Biological activity markers can be classified into serological, faecal and miscellaneous categories. Acute phase reactants levels correlate with disease activity and some can be used to help predict relapse. Cytokines and adhesion molecules are elevated in active disease inconsistently. Faecal markers are useful in assessment of disease activity and relapse.

CONCLUSIONS

Acute phase reactants and faecal markers are useful to assess the disease activity in clinical practice. More data are required on cytokines and adhesion molecules. C-reactive protein, erythrocyte sedimentation rate, interleukins and faecal markers may be useful in predicting a relapse.

Effect of chronic cold stress on intestinal epithelial cell proliferation and inflammation in rats

The present study evaluated the effect of chronic cold stress on intestinal epithelial cell proliferation and inflammation. Male Wistar rats were subjected to cold exposure for three weeks. At the end of the cold exposure, intestinal cell proliferation, luminal nitrite and protein levels, intestinal myeloperoxidase activity and mast cell numbers were evaluated. Severely compromised proliferation rate of the crypt-base cells was observed under chronic stress conditions. Cells isolated from stressed rats showed a decreased DNA content in villus and lower villus cell fractions and an increased DNA content in the crypt cells, as compared to controls. Chronic cold stress resulted in increased luminal nitrite, luminal protein levels, and intestinal myeloperoxidase activity. The number of mast cells was significantly elevated under chronic stress conditions. Chronic cold stress resulted in a compromised intestinal epithelial cell proliferation rate and induced inflammation in the rat small intestine, through the combined action of nitric oxide, neutrophils and mast cells.

Long-term treatment with anti-α4 integrin antibodies aggravates colitis in Gαi2-deficient mice

Targeted deletion of the heterotrimeric G protein, Galphai2, in mice induces lethal colitis closely resembling ulcerative colitis. In chronic colitis, migration of circulating leukocytes into the intestinal mucosa is partially dependent on alpha4 integrins. In previous studies, short-term administration of anti-alpha4 integrin antibodies has been shown to attenuate intestinal inflammation, and here we elucidate the effect of long-term administration of anti-alpha4 integrin antibodies on colitis in Galphai2(-/- )mice. Long-term blockade of alpha4 integrin significantly increased the severity of colitis in Galphai2(-/-) mice. The inflammation was confined to the colon, associated with increased cancer in situ, destruction of crypt architecture, and increased production of IL-1beta, TNF-alpha and IFN-gamma. Blockade of alpha4 integrin reduced the recruitment of activated T cells to the small intestine. In strong contrast, there were significantly higher numbers of activated T cells in the colonic lamina propria and epithelium, most probably due to in situ proliferation. Furthermore, treatment with alpha4 integrin antibodies induced decreased levels of total IgA and IgG in sera, whereas total IgM levels were unchanged. These new findings may have implications in the understanding of the progression of chronic intestinal inflammation.

Is portal hypertension associated with protein-losing enteropathy?

BACKGROUND AND AIM

Hypoalbuminemia in patients with decompensated cirrhosis has traditionally been assumed to be a result of to impaired liver synthesis; however, protein-losing enteropathy (PLE) may also contribute. The aim of this study was to assess whether hypoalbuminemic cirrhotic patients with portal hypertension had evidence of PLE.

METHODS

Sixteen patients with alcoholic cirrhosis, hypoalbuminemia and portal hypertension underwent whole gut lavage with polyethylene glycol solution. The effluent obtained was analyzed for albumin, immunoglobulin (Ig)G and alpha1-antitrypsin (alpha1-AT). Serum C-reactive protein (CRP) was also measured to assess the systemic inflammatory response.

RESULTS

Twelve of the 16 enrolled patients had a persistently low albumin concentration at the time of lavage. Only one patient (who was subsequently found to have celiac disease) had elevated concentrations of lavage albumin, alpha1-AT and IgG levels. There was a significant correlation between lavage albumin and alpha1-AT (r = 0.671, P = 0.024), and between lavage albumin and IgG (r = 0.614, P = 0.045). There was no correlation between serum albumin and lavage proteins. Six patients had elevated serum CRP levels, but serum albumin or lavage protein concentrations did not correlate with serum CRP.

CONCLUSION

There is no evidence of a significant PLE in patients with alcoholic cirrhosis, hypoalbuminemia and portal hypertension.

Frequency of continuing mucosal inflammation in clinically inactive Crohn's disease

The treatment goal in Crohn's disease is clinical remission, not complete mucosal healing. The incidence of mucosal inflammation in Crohn's disease patients in clinical remission is not known. Whole gut lavage is an objective method of assessing mucosal inflammation. We aimed to assess levels of mucosal inflammatory activity in a group of patients with clinically inactive Crohn's disease. We prospectively assessed 30 patients with inactive Crohn's disease and 28 controls. Inactive disease was defined as Crohn's disease activity index of less than 150. All underwent whole put lavage, with analysis of whole gut lavage fluid IgG, haemoglobin, interleukin-1 beta, interleukin-8 and granulocyte elastase. Serum inflammatory parameters were collected for comparison. Of the 30 patients with Crohn's disease, 10 (33%) had an abnormal immunoglobulin G, 21 (70%) had an elevated interleukin-1 beta 20 (66%) interleukin-8 and 10 (33%) granulocyte elastase in the whole gut lavage fluid. 58% of patients had either 1 or 2 abnormal results. In contrast only 10% had 1 or 2 abnormal serum results. Few abnormalities were present in lavage fluid or serum of the control population. We concluded that ongoing mucosal inflammation is detectable in whole gut lavage fluid of up to 2/3 of Crohn's disease patients in clinical remission.

Gut luminal neutrophil migration is influenced by the anatomical site of Crohn's disease

BACKGROUND

Clinical differences between small- and large-bowel Crohn's disease have been demonstrated. Neutrophil migration and degranulation are important effector mechanisms in gut damage. Granulocyte elastase, a neutrophil-bound enzyme, interleukin 8 and 1beta can be detected in whole-gut lavage fluid. We aimed to assess differences between large- and small-bowel Crohn's disease.

METHODS

A total of 167 patients with active inflammatory bowel disease (118 Crohn's disease, 49 ulcerative colitis) underwent whole-gut lavage with a polyethylene glycol electrolyte solution. Granulocyte elastase was assayed using an enzyme substrate reaction, IL-8 and IL-1beta by ELISA.

RESULTS

Twenty-seven of 36 patients with isolated colonic Crohn's disease had detectable granulocyte elastase (median 0.259 pKat/l, range < 0.039-2.742 microKat/l), whereas 3 of 15 with small-bowel involvement alone had detectable granulocyte elastase (median < 0.039 microKat/l, range < 0.039-0.266 microKat/l; P < 0.0001). Granulocyte elastase levels were significantly higher in patients with ileocolonic disease and post-ileocaecal resection compared with small-bowel disease alone. IL-8 (P< 0.0001) and IL-1beta (P < 0.04) levels differed between colonic and ileal distributions. No variations were seen in ulcerative colitis.

CONCLUSIONS

Neutrophil migration to the gut lumen in Crohn's disease is a feature of colonic disease irrespective of associated ileal lesions. This suggests that bacterial-derived chemo-attractants may play a role. High levels of IL-8 in colonic disease are consistent with this hypothesis.

Abnormal intestinal permeability predicts relapse in inactive Crohn disease

BACKGROUND

Trials of maintenance therapy in quiescent Crohn disease are often underpowered and there is need for objective markers that predict relapse. Intestinal permeability (IP) has been identified as such a marker although it is unknown how this relates to proposed clinical and blood markers of relapse. We aimed to assess the predictive value of intestinal permeability together with clinical and blood markers in a group of patients with inactive Crohn disease.

METHODS

We assessed 50 patients with inactive Crohn disease. Inactive disease was defined as a Crohn disease activity index of less than 150. Intestinal permeability was measured by the urinary excretion of lactulose and rhamnose and data relating to postulated clinical and blood markers predictive of relapse were collected. Follow-up for one year assessed whether patients had relapsed or remained in remission.

RESULTS

Of the 18 patients with abnormal intestinal permeability, 10 remained in remission and 8 relapsed. Of the 32 with a normal result, 31 remained in remission and 1 relapsed. Patients with abnormal intestinal permeability are significantly more likely to relapse than those with a normal result (chi-square = 14.3; P = 0.0001; relative risk 18). Those that relapsed had shorter disease duration. Multiple regression analysis identifies IP to be an independent variable.

CONCLUSIONS

Abnormal intestinal permeability in patients with inactive Crohn disease predicts relapse. This is superior to clinical and blood markers. It is likely that this is due to ongoing subclinical mucosal inflammation. This may be of use when designing clinical trials of maintenance therapy.

Biochemical tests in diseases of the intestinal tract: their contributions to diagnosis, management, and understanding the pathophysiology of specific disease states

Biochemical testing plays a major role in the complete evaluation of patients with suspected or established intestinal disease. We have classified these tests according to the medium in which they are performed: breath tests, including isotopic and nonisotopic tests, fecal tests, urine tests, serum tests, tissue tests, and other tests. The principles of various tests are outlined, and the role of each test in the evaluation of particular gastrointestinal disorders is discussed.

Management of the first presentation of severe acute colitis

Prompt diagnosis and exclusion of infection requires a minimum of rigid sigmoidoscopy, rectal mucosal biopsy and stool culture. Admission to hospital is mandatory for patients with features of severe disease, or who are in their first attack of ulcerative colitis and have bloody diarrhoea, even if the criteria for severe disease are not met. Once admitted, the patient should be monitored by plain abdominal X-ray, full blood count, serum albumin and C reactive protein on alternate days; temperature and pulse rate should be recorded four times per day. Treatment should be instituted as soon as the diagnosis is made with an intravenous corticosteroid (hydrocortisone 100 mg intravenously, four times daily, or equivalent). Antibiotics may be included if infection cannot be confidently excluded. Free diet can be allowed but attention should be given to nutritional, fluid and electrolyte status with intravenous replacement if necessary. Any evidence of colonic dilatation occurring despite maximal therapy should be regarded as an absolute indication for colectomy. The patient should be kept fully informed from an early stage about the likely natural history of the condition and about the possible therapeutic options including surgery. Cyclosporin therapy should be reserved for patients who have a poor response to the first 3-4 days of corticosteroid therapy, particularly those with serum C reactive protein > 45 mg/l and who do not yet have absolute indications for colectomy. Most patients who have not convincingly responded within 10 days of starting full medical therapy should undergo colectomy, although partial responders who are afebrile may reasonably continue for up to 14 days before a final decision. Approximately 30-40% of patients with severe colitis will need colectomy within the first 6 months. With optimal management, mortality should be zero, but better medical therapies are urgently needed to reduce the colectomy rate.

Investigation of neutrophils in the gut lumen by assay of granulocyte elastase in whole-gut lavage fluid

BACKGROUND

Intestinal neutrophils can be studied by radiolabelling techniques and by cytology of whole-gut lavage fluid. Our aim was to evaluate the use of a biochemical test for the presence of these cells in whole-gut lavage fluid.

METHOD

Whole-gut lavage was performed by having the patients drink a polyethylene-glycol-electrolyte solution; the clear fluid passed per rectum after complete bowel cleansing had been collected. In 203 patients granulocyte elastase was assayed in sonicated unfiltered lavage fluid, using the specific enzyme substrate L-pyroglutamyl-I-prolyl-L-valine-p-nitroanilide. Free granulocyte elastase was also assayed in filtered (that is, cell-free) lavage fluid in 39 of the 43 patients in whom the enzyme was present in unfiltered fluid. In 47 of the patients, cells were also separated by density gradient centrifugation, and counted.

RESULTS

Granulocyte elastase concentration correlated significantly with cell count (r = 0.80, p < 0.001). Granulocyte elastase concentration was high (> 100 nkat/l) in fluid from 25 of 68 inflammatory bowel disease patients and 6 of 135 others with radiation colitis, diverticulitis, pericolic abscess, and use of non-steroidal anti-inflammatory drugs. In patients with detectable total granulocyte elastase, cell-free granulocyte elastase was present in 11 of 29 with inflammatory bowel disease and 1 of 10 others.

CONCLUSION

Whole-gut lavage fluid samples can readily be used to investigate luminal inflammatory cells.

Soluble Fc gamma receptor III (CD 16) and eicosanoid concentrations in gut lavage fluid from patients with inflammatory bowel disease: reflection of mucosal inflammation

BACKGROUND

Activated neutrophils cause tissue injury in inflammatory bowel disease (IBD). Upon activation, they shed soluble Fc gamma IIIb receptors (sFc gamma RIIIb). The subsequent inflammatory response is modulated by several mediators, including neutrophil derived leukotriene B4 (LTB4), thromboxane B2 (TXB2), and prostaglandin E2 (PGE2). The aim of this study was to determine the value of gut lavage sFc gamma RIII and eicosanoid measurements for the assessment of mucosal inflammation in IBD.

METHODS

A total of 18 patients with active IBD, 10 ulcerative colitis (UC), and eight Crohn's disease (CD), and 12 control patients underwent whole gut lavage. Disease activity, endoscopic appearance, and histopathology were graded. Samples were processed for the determination of sFc gamma RIIIb, LTB4, PGE2, and TXB2.

RESULTS

Soluble Fc gamma RIIIb concentrations were increased in both IBD groups. Significant correlations were seen between sFc gamma RIIIb and LTB4 values with histology scores. Mean eicosanoid lavage fluid concentrations in control patients were 14.1 pg/ml for LTB4, 5.6 pg/ml for PGE2, and 397 pg/ml for TXB2. Concentrations of all eicosanoids in IBD patients were significantly increased: LTB4 in UC: mean 73.2 pg/ml, in CD: 96.4 pg/ml (both p < 0.01 v controls). PGE2 in UC: 20.2 pg/ml, in CD: 43.4 pg/ml (p < 0.01). TXB2 in UC: 719.3 pg/ml, in CD: 180.6 pg/ml (both p < 0.05).

CONCLUSIONS

Whole gut lavage fluid analysis is an effective method to study mucosal eicosanoid production. Soluble Fc gamma RIIIb concentrations in gut lavage fluid closely correlate with histological signs of mucosal inflammation and with lavage LTB4 concentration. These data suggest that lavage Fc gamma RIIIb assessment may be used as a simple assay to estimate mucosal neutrophil infiltration in IBD.

Analysis of disease distribution, activity and complications in the patient with inflammatory bowel disease

Management strategies in Crohn's disease and ulcerative colitis should be based on up-to-date information on disease distribution, extent, activity and complications. A system of structured analysis is suggested, with separate consideration of destructive ulceration, inflammatory activity and other factors. Direct investigation of gut immunity by using whole gut lavage fluid (WGLF) is a valuable new technique of clinical investigation in IBD and related disorders. Recent studies have shown that the concentrations of plasma-derived proteins in WGLF provide objective measures of disease activity; and that this activity is a separate phenomenon from destructive ulceration and fibrosis. Neutrophils in the lumen can be in- investigated by cytology, or by assay of neutrophil elastase in WGLF. Cytokines and other immuno-regulatory mediators can also be detected. These new techniques can provide a description of intestinal immunity and inflammation, based on a non-invasive test of 2-4 h duration. Work in progress shows that patients who respond clinically to elemental diet treatment have unusually high concentrations of soluble IL2 receptor in WGLF; cytokine profiles may facilitate the selection of patients suitable for other new treatment modalities.

Treatment of active distal ulcerative colitis with immunoglobulin G enemas

Seven patients with active distal ulcerative colitis were treated with IgG enemas given as a daily bedtime retention enema for two weeks. Evaluation of effect was assessed by means of sigmoidoscopy with biopsy, measuring acute phase reactants in peripheral blood, and measuring the faecal protein loss. Clinical signs of active disease were registered by the patients on a diary chart. Five patients completed the treatment period, two patients were withdrawn after 7 and 10 days due to deterioration of disease. Four patients did not register any effect, whereas one patient improved clinically. In conclusion, rectally administered IgG did not exert any effect on rectal ulcerative colitis in our study.

Gut lavage fluid protein concentrations: objective measures of disease activity in inflammatory bowel disease

BACKGROUND

Fluid obtained by whole gut lavage normally contains traces of immunoglobulin (Ig) G, albumin, and alpha-1-antitrypsin; higher concentrations have been found in patients with inflammatory bowel disease (IBD).

METHODS

In a prospective study, 53 lavages were performed in 45 IBD patients (27 Crohn's disease, 18 ulcerative colitis), in whom disease activity was simultaneously assessed by Crohn's Disease Activity Index or Powell Tuck index. Concentration of IgG in lavage fluid was measured by enzyme-linked immunosorbent assay, and of albumin and alpha-1-antitrypsin by immunoturbidimetry.

RESULTS

For IgG, concentrations in lavage fluid correlated closely with activity indices: in Crohn's disease, r = 0.723 (P < 0.0001), in ulcerative colitis, r = 0.714 (P < 0.0001). Results for albumin and alpha-1-antitrypsin concentrations were similar to those for IgG, but they were less sensitive in detecting active disease. However, this method cannot be used as a diagnostic test for IBD; normal results were obtained for IgG in 6 (all inactive) of 42 lavages in patients who had unequivocal radiological or endoscopic abnormalities.

CONCLUSIONS

Assay of protein concentrations in gut lavage fluid is a simple, objective means of grading disease activity in patients with IBD; its potential uses are likely to be in the evaluation of complex cases and in clinical trials.

Nitric oxide release in response to gut injury

We evaluated nitric oxide release in several models of intestinal inflammation through luminal nitrite concentrations. In anesthetized rabbits, piglets, and guinea pigs, luminal lavages were collected from loops of normal or injured small intestine. Lavages were analyzed spectrophotometrically for nitrite (Griess reagent) and protein. Myeloperoxidase (MPO) content of intestinal segments was used as an index of granulocyte infiltration and intestinal inflammation. Acute ileal inflammation was induced by luminal acetic acid + casein in rabbits and luminal deoxycholate in neonatal piglets and adult rabbits. Chronic ileitis was induced in guinea pigs by intraluminal trinitrobenzenesulfonic acid. In each model nitrite levels in ileal lavages were significantly greater than control loops/animals. Increased luminal protein and intestinal MPO activity paralleled the changes in nitrite levels. To determine whether nitric oxide production influenced mucosal repair, segments of ileum were perfused with the L-arginine antagonist NG-nitro-L-arginine methyl ester (L-NAME, 10 mg/ml) after acute acetic acid + casein exposure. L-NAME administration reversed the decline in epithelial permeability characteristic of epithelial restitution, causing an increase in epithelial permeability which was readily reversible. These results suggest that nitrite production is a useful index of gut injury and that nitric oxide may contribute to the functional repair of the epithelial barrier under acute conditions.

Haemoglobin in gut lavage fluid as a measure of gastrointestinal blood loss

To detect and measure occult gastrointestinal bleeding, we have measured haemoglobin concentrations (by HemoQuant) in the clear fluid obtained after whole-gut lavage. In subjects with healthy gastrointestinal tracts, lavage-fluid haemoglobin concentrations were 0.5-5.1 mg/L, equivalent to daily blood loss of 0.1-1.1 mL. High concentrations were found for patients with colorectal cancer, severe diverticular disease, and rectal varices, in seven of sixteen patients with active inflammatory bowel disease, and in four patients with iron-deficiency anaemia thought to be due to gastrointestinal bleeding. In these four patients, estimated blood loss ranged from 2.6-24.5 mL per day. This method could have various research and clinical applications.

Systemic and mucosal antibodies to Klebsiella in patients with ankylosing spondylitis and Crohn's disease

Whole gut lavage fluid is a useful source of material for the study of intestinal immunity and inflammation in humans. Systemic and mucosal antibodies to Klebsiella pneumoniae were measured by enzyme linked immunosorbent assay (ELISA) in serum samples and whole gut lavage fluid from 14 patients with ankylosing spondylitis, 14 with Crohn's disease, and 16 immunologically normal controls. As the concentration of IgG in whole gut lavage fluid reflects disease activity in Crohn's disease, this approach was used to detect intestinal inflammation in patients with ankylosing spondylitis who also had disease activity and use of non-steroidal anti-inflammatory drugs (NSAIDs) recorded. Small intestinal permeability to cellobiose and mannitol was also studied. In serum samples, levels of IgA antibody to klebsiella were high in patients with Crohn's disease and in patients with active ankylosing spondylitis, and were significantly correlated with the erythrocyte sedimentation rate in patients with ankylosing spondylitis. Levels of IgG antibody to klebsiella were also high in patients with Crohn's disease. Studies of whole gut lavage fluid showed similar levels of IgA antibody to klebsiella in the three study groups, but levels of whole gut lavage fluid IgM and IgG antibodies to klebsiella were high in patients with Crohn's disease. Levels of IgG in whole gut lavage fluid were high in patients with Crohn's disease but in only one patient with ankylosing spondylitis, though the cellobiose/mannitol permeability ratio was abnormal in eight of 13 patients with ankylosing spondylitis. It is concluded that high levels of serum IgA antibody to klebsiella are not specific to ankylosing spondylitis, and that there is no evidence of an abnormal intestinal IgA antibody response to klebsiella in patients with ankylosing spondylitis.