Interleukin-4 inhibits the increased production of vascular endothelial growth factor by peripheral blood mononuclear cells in patients with inflammatory bowel disease

BACKGROUND/AIMS: Vascular endothelial growth factor (VEGF), a potent angiogenic, permeability-enhancing cytokine plays an important role in tissue repair and chronic inflammatory disorders. Peripheral blood mononuclear cells (PBMCs) and the inflamed mucosa have been demonstrated to be main sources of the recently described circulating VEGF in patients with inflammatory bowel disease (IBD). There is no current information about the influence of immunoregulatory cytokines on VEGF in IBD. The present study examines the effect of interleukin-4 on the increased VEGF production of PBMCs in patients with IBD. METHODOLOGY: Unstimulated PBMCs from 17 patients with Crohn's disease, 16 patients with ulcerative colitis and 8 healthy controls were cultured with or without IL-4. VEGF production was measured in the supernatant using an enzyme-linked immunosorbent assay. RESULTS: IL-4 led to a significant reduction of the VEGF production by PBMCs of both active Crohn's disease patients (471.7 +/- 377.5 pg/mL vs. 208.2 +/- 123.2 pg/mL, P = 0.018, n = 7) and active ulcerative colitis patients (177.1 +/- 79.4 pg/mL vs. 87.4 +/- 77.2 pg/mL, P = 0.008, n = 9). IL-4 inhibited significantly the VEGF production by PBMCs of patients with inactive Crohn's disease (179.2 +/- 133.9 pg/mL vs. 87.7 +/- 56.6 pg/mL, P = 0.005, n = 10). There was no significant difference of VEGF release by PBMCs cultured with IL-4 in patients with active Crohn's disease or active ulcerative colitis compared with PBMCs cultured without IL-4 in patients with inactive disease and healthy controls (112.6 +/- 41.9 pg/mL, n = 8). CONCLUSIONS: IL-4 has been shown to reduce the increased VEGF production of PBMCs in patients with IBD to normal levels. The known defective immunosuppressive effect of IL-4 in IBD may contribute to the pathogenic cascade leading to inflammation by VEGF mediated mechanisms.     

Immunohistochemical localization of vascular endothelial growth factor in colonic mucosa of patients with inflammatory bowel disease

BACKGROUND/AIMS: Significantly enhanced serum levels of VEGF (vascular endothelial growth factor) were found in patients with inflammatory bowel disease. Peripheral blood mononuclear cells have been identified as one of the origins of the circulating VEGF. The present investigation examines the localization of VEGF at the site of inflammation in colonic mucosa of patients with Crohn's disease and ulcerative colitis. METHODOLOGY: Immunohistochemical localization of VEGF and immunostaining for leukocytes were performed in colonic mucosal biopsies of 41 patients with Crohn's disease, 26 patients with ulcerative colitis and normal mucosal specimens of 5 patients with irritable bowel syndrome. Measurement of immunohistochemical staining for VEGF and for leukocytes within the epithelium and the lamina propria was performed separately by area morphometry using a computerized cell analysis system. RESULTS: In both patients with Crohn's disease and ulcerative colitis immunohistochemical staining for VEGF within the lamina propria of inflamed colonic mucosa was significantly higher compared with noninflamed mucosa (Crohn's disease: 4.26% vs. 0.07%, P < 0.001; ulcerative colitis: 3.68% vs. 0.32%, P = 0.001). There was a significant correlation between immunostaining for leukocytes and VEGF within the lamina propria in both patients with Crohn's disease (r = 0.73, P < 0.05)) and ulcerative colitis (r = 0.67, P < 0.05). In Crohn's disease immunostaining for VEGF within the epithelium was significantly higher in inflamed mucosa compared with noninflamed mucosa (9.85% vs. 0.63%, P < 0.001). In contrast, strong immunostaining for VEGF has been observed in the epithelium of noninflamed mucosa (7.60%, P < 0.003), as well as in inflamed mucosa of patients with active ulcerative colitis (9.68%, P < 0.002) compared with noninflamed mucosa of patients with inactive ulcerative colitis (1.39%). CONCLUSIONS: The present data indicate, that the increased VEGF expression within the epithelium and the interstitial accumulation of VEGF-producing leukocytes in inflamed mucosa may play an important role in the inflammatory mechanisms of Crohn's disease and ulcerative colitis.     

Increased production of vascular endothelial growth factor by peripheral blood mononuclear cells in patients with inflammatory bowel disease

BACKGROUND: Vascular endothelial growth factor (VEGF) is a potent angiogenic, vascular permeability-enhancing cytokine with overexpression in various pathological disorders, including tumour growth, chronic inflammation and tissue repair. Recent studies have shown significantly increased serum levels of VEGF in patients with inflammatory bowel disease. The origin of the circulating VEGF is still unknown. The present investigation examines the VEGF production by peripheral blood mononuclear cells (PBMCs) in patients with inflammatory bowel disease. METHODS: VEGF levels were measured in culture supernatants of unstimulated PBMCs of 27 patients with inflammatory bowel disease and 10 healthy volunteers using a solid phase ELISA. In addition, VEGF serum levels were determined. RESULTS: PBMCs of both active Crohn's disease patients (1142.6+/-483.9 pg/ml, P < 0.001, n = 12) and active ulcerative colitis patients (748.0+/-637.6 pg/ml, P = 0.006, n = 4) produced significantly higher amounts of VEGF compared with PBMCs of healthy volunteers (113.4+/-101.8 pg/ml, n = 10). In addition, there was a significantly increased VEGF production by PBMCs of patients with active disease compared with PBMCs of patients with quiescent Crohn's disease (261.6+/-254.8 pg/ml, P < 0.001, n = 7) and inactive ulcerative colitis (147.7+/-100.3 pg/ml, P = 0.02, n = 4). There was no significant difference in VEGF release between patients with inactive inflammatory bowel disease and healthy controls. CONCLUSIONS: Significantly increased VEGF production by PBMCs was found in patients with active Crohn's disease and active ulcerative colitis. The study helps to clarify one of the origins of the significantly enhanced VEGF serum levels in patients with active inflammatory bowel disease observed in recent studies.     

Expression of vascular adhesion molecules in inflammatory bowel disease.

The expression of the vascular adhesion molecules ELAM-1 (endothelial leukocyte adhesion molecule 1) and VCAM-1 (vascular cell adhesion molecule 1) was evaluated in colonic mucosa of patients with inflammatory bowel disease and normal controls by immunocytochemistry. VCAM-1 was found to be constitutively expressed in lymphoid aggregates in normal colonic mucosa and was not significantly enhanced or altered in distribution in mucosa of patients with inflammatory bowel disease regardless of the activity of the inflammatory process. In contrast, ELAM-1 was not detected by these techniques in normal colonic mucosa (n = 11) or in colonic mucosa of patients with inflammatory bowel disease which was either uninvolved or quiescent (n = 30). However, high levels of ELAM-1 were consistently found on endothelial surfaces in association with active inflammation in affected areas of colonic mucosa in patients with either ulcerative colitis (n = 27) or Crohn's colitis (n = 9). In addition, ELAM-1 appeared to be present within neutrophils which had migrated into crypt abscesses in affected mucosa. Similar analysis was carried out in the cotton-top tamarin (CTT), a primate that experiences an idiopathic chronic diffuse colitis resembling human ulcerative colitis. Although anti-human VCAM-1 antibodies did not react with the CTT, anti-human ELAM-1 stained endothelial surfaces in mucosal biopsies from CTT with active colitis. No ELAM-1 was identified in mucosa of CTT in which colitis activity was quiescent. Thus ELAM-1 is expressed on colonic endothelial surfaces in association with inflammation and may play an important role in facilitating leukocyte migration into sites of active IBD involvement.     

Immunoglobulin containing cells in inflammatory bowel disease of the colon: a morphometric and immunohistochemical study.

Immunoglobulin containing cells in rectal and sigmoid colonic mucosa in endoscopically obtained biopsies from 10 patients with ulcerative colitis and 10 patients with Crohn's disease were studied, using an indirect immunoperoxidase technique. These findings were compared with the immunoglobulin containing cell number in colonic biopsies from 10 control patients with no evidence of colitis. In biopsies from the 20 patients with inflammatory bowel disease a marked increase in area of the lamina propria per millimetre mucosa length was found. In ulcerative colitis a marked increase in number of IgG containing cells was observed. In Crohn's disease the increase in IgG containing cell number is dependent on the degree of activity of inflammation. In quiescent of active Crohn's disease of the colon we found a significant increase of the IgM containing cells. The number of IgM containing cells per millimetre mucosa length will differentiate the pathology of Crohn's disease from ulcerative colitis.     

Different distribution of mast cells and macrophages in colonic mucosa of patients with collagenous colitis and inflammatory bowel disease

BACKGROUND/AIMS: Chronic inflammatory cells in colonic mucosa is a histopathologic feature in patients with collagenous colitis and inflammatory bowel disease. The aim of this study was to compare the distribution of mast cells and macrophages in the colonic mucosa of patients with collagenous colitis, Crohn's disease, and ulcerative colitis. METHODOLOGY: Patients with histologically confirmed collagenous colitis (n = 13), Crohn's disease (n = 20) or ulcerative colitis (n = 20) and normal control patients (n = 20) were included in this study. Biopsy specimens were obtained from the sigmoid colon of each patient, and immunostained using antibodies to tryptase (AA1) and CD68. The number of mast cells and macrophages located in upper and lower part of the lamina propria was determined. RESULTS: The number of mast cells in the upper part of lamina propria in patients with collagenous colitis (286 +/- 89/mm2, mean +/- SD), Crohn's disease (330 +/- 84/mm2) and ulcerative colitis (355 +/- 90/mm2), was higher than normal controls (201 +/- 44/mm2). The number of mast cells in the lower part of lamina propria in patients with Crohn's disease (345 +/- 87/mm2) and ulcerative colitis (363 +/- 86/mm2) was higher than collagenous colitis (266 +/- 63/mm2) and normal controls (309 +/- 60/mm2). The number of macrophages in the lower part of lamina propria in patients with Crohn's disease (330 +/- 63/mm2) and ulcerative colitis (301 +/- 60/mm2) was higher than in collagenous colitis (247 +/- 46/mm2) and normal controls (242 +/- 52/mm2), although there were no significant differences in the number of macrophages present in the upper part of the lamina propria among the four groups. CONCLUSIONS: Our data showed the presence of a different distribution of mast cells and macrophages in collagenous colitis and inflammatory bowel disease, and these suggest that because mucosal mast cells have been implicated in the development of Th2 response collagenous colitis is more of a Th2 type reaction rather than Th1.     

Enhanced colonic nitric oxide generation and nitric oxide synthase activity in ulcerative colitis and Crohn's disease.

Recent studies have suggested that nitric oxide (NO.), the product of nitric oxide synthase in inflammatory cells, may play a part in tissue injury and inflammation through its oxidative metabolism. In this study the colonic generation of oxides of nitrogen (NOx) and nitric oxide synthase activity was determined in ulcerative colitis and Crohn's disease. Colonic biopsy specimens were obtained from inflammatory bowel disease patients and from normal controls. Mucosal explants were cultured in vitro for 24 hours and NOx generation was determined. Nitric oxide synthase activity was monitored by the conversion of [3H]-L-arginine to citrulline. Median NOx generation by inflamed colonic mucosa of patients with active ulcerative colitis and Crohn's colitis was 4.2- and 8.1-fold respectively higher than that by normal human colonic mucosa. In ulcerative colitis and Crohn's colitis nitric oxide synthase activity was 10.0- and 3.8-fold respectively higher than in normal subjects. Colonic NOx generation is significantly decreased by methylprednisolone and ketotifen. The decrease in NOx generation by cultured colonic mucosa induced by methylprednisolone suggests that NO synthase activity is induced during the culture and the steroid effect may contribute to its therapeutic effect. Enhanced colonic NOx generation by stimulated nitric oxide synthase activity in ulcerative colitis and Crohn's disease may contribute to tissue injury.     

Ulcerative colitis--a disease characterised by the abnormal colonic epithelial cell?

The leakiness of the cell membranes of colonic epithelial cells isolated by the collagenase/Dispase technique from normal or diseased colons was assessed in a 4 h 51Cr release assay. Cells from normal, adenoma bearing or cancer bearing colons showed 51Cr release of 8% or less in almost all of 46 cell populations tested. In contrast, cells from mucosa affected by ulcerative colitis [11.9 (4.3%) n = 23] or Crohn's disease [8.4 (2.7%) n = 18] released significantly more 51Cr than the non-inflamed groups. Values are expressed as mean (SD). Overall, release values were greater in ulcerative colitis than Crohn's disease (p less than 0.01). In Crohn's disease, cells obtained from histologically inflamed mucosa released significantly more 51Cr [9.7 (2.5%) n = 11] than those from non-inflamed mucosa [6.4 (1.5%) n = 7, p less than 0.02] whereas, in ulcerative colitis, abnormal release values were found in 8 of 13 cell populations isolated from mucosa showing no histological evidence of active disease. In five patients with distal ulcerative colitis, cells from mucosa not apparently involved demonstrated normal 51Cr release in four of five studies despite abnormal release from cells from involved mucosa suggesting that a diffuse abnormality of the colonic epithelial cell is not usually present. These data indicate that chronic mucosal inflammation per se is associated with abnormalities of the colonic epithelial cell but that, in ulcerative colitis, the abnormality remains in many patients with quiescent disease. Identification of the local factors responsible for such an abnormality may contribute to an understanding of the pathogenesis of ulcerative colitis.     

Histochemical demonstration of desialation and desulphation of normal and inflammatory bowel disease rectal mucus by faecal extracts.

Experiments were carried out to assess the susceptibility of normal and inflammatory bowel disease rectal mucus to desulphation and desialation by faecal extracts and by bacterial sialidase. The effects were assessed histochemically using a combined high iron diamine (HID) and alcian blue (AB) stain for sulphomucins and sialomucins. Rectal mucus in biopsies from controls (irritable bowel syndrome) and patients with ulcerative colitis or Crohn's disease was resistant to desialation by Clostridium perfringens sialidase, but susceptible to desialation and desulphation by bacteria-free extracts of normal faeces. Periodic acid-Schiff (PAS) staining of adjacent sections similarly treated showed retention of neutral mucus. One faecal extract selectively desulphated all 42 biopsies, causing the goblet cells to change from HID positive to AB positive, suggesting that most, or all HID positive cells also contain sialomucins. This alters the interpretation of previous histochemical studies. Faecal extracts from patients with active ulcerative colitis (n = 6) had desialating and desulphating effects similar to faecal extracts from normal subjects (n = 6). Ulcerative colitis (n = 21), Crohn's disease (n = 18), and control (irritable bowel syndrome) (n = 17) rectal biopsies all showed similar susceptibility to desulphation by a pooled normal faecal extract, but rectal biopsies from patients with Crohn's disease proved more resistant to desialation than control or ulcerative colitis biopsies (p less than 0.02). These studies imply that colonic mucus undergoes continual desulphation and desialation in vivo as a result of faecal enzyme activity that is probably mainly of bacterial origin. Altered susceptibility of colonic mucus to this may be important in the pathogenesis of colonic disease.     

Reduced mucosal antimicrobial activity in Crohn's disease of the colon

OBJECTIVES: In order to maintain the mucosal barrier against luminal microorganisms the intestinal epithelial cells synthesise various broad-spectrum antimicrobial peptides including defensins and cathelicidins. Recent studies indicate that both may be deficient in Crohn's disease. To elucidate the possible functional consequences of this deficiency antimicrobial activity in colonic mucosa from patients with inflammatory bowel disease and healthy controls was investigated. METHODS: A flow cytometric assay was established to quantitate bacterial killing and test the antibacterial activity of cationic peptide extracts from colonic biopsies taken from patients with active or inactive ileocolonic or colonic Crohn's disease (n = 22), ulcerative colitis (n = 29) and controls (n = 13) against clinical isolates of Bacteroides vulgatus and Enterococcus faecalis or the reference strains Escherichia coli American Type Culture Collection (ATCC) 25922 and Staphylococcus aureus ATCC 25923. RESULTS: Compared with controls and ulcerative colitis there was a reduced antimicrobial effect in Crohn's disease extracts that was most evident against B. vulgatus. The antimicrobial effect against E. coli and E. faecalis was significantly lower in Crohn's disease compared with ulcerative colitis. Activity against S. aureus disclosed a similar pattern, but was less pronounced. The differences were independent of the inflammation status or concurrent steroid treatment. Bacteria incubated with biopsy extracts from ulcerative colitis patients frequently showed a characteristic change in cell size and granularity, compatible with more extensive membrane disintegration, compared with bacteria incubated with extracts from controls or Crohn's disease. CONCLUSION: Crohn's disease of the colon is characterized by a diminished functional antimicrobial activity that is consistent with the reported low antibacterial peptide expression.     

Collagenase-3 (MMP-13) expression by inflamed mucosa in inflammatory bowel disease

OBJECTIVE: To determine whether the expression of collagenase-3 (MMP-13) in biopsies from patients with inflammatory bowel disease is correlated with histological inflammation parameters. MATERIAL AND METHODS: Fifty-nine patients with inflammatory bowel disease were included in the study. The control group comprised 20 patients free of inflammatory disease and ten patients with acute diverticulitis. MMP-13 expression was determined by immunohistochemical staining and the specimens were assigned a histological inflammation score. RESULTS: It was found that 62.8% of patients with ulcerative colitis (UC) and 54.1% of patients with Crohn's disease (CD) showed MMP-13-positive immunostaining in biopsies from affected areas. MMP-13-positive staining was more intense in ulcerated colonic mucosa. A positive and significant correlation was found between MMP-13 expression and the histological inflammation scores in mucosal samples from patients with CD (r = 0.74, p < 0.0001) or UC (r = 0.62, p < 0.0001). However, no MMP-13-positive immunostaining was found in either the biopsy specimens of the control group or those biopsies taken from patients with UC or CD in microscopically confirmed non-affected areas of the colonic mucosa. Similarly, colonic mucosa samples of the 10 patients with acute diverticulitis did not show immunostaining for MMP-13. CONCLUSIONS: Our findings demonstrating the absence of MMP-13 expression in non-inflamed colonic mucosa or in acute diverticulitis, as well as a positive correlation between elevated MMP-13 expression and histological criteria of inflammation in patients with inflammatory bowel diseases (CD and UC) suggest a role of the protease in the pathogenesis of these latter processes.     

Prostanoid synthesis by cultured intestinal epithelial and mononuclear cells in inflammatory bowel disease.

Intestinal epithelial and mononuclear cells were isolated from normal colonic mucosa and from intestinal mucosa of inflammatory bowel disease patients. Prostanoid synthesis by primary cultures of intestinal mononuclear cells were four to six fold higher than its synthesis by primary cultures of epithelial cells. Prostaglandin E2, prostacyclin and thromboxane A2 synthesis by cultured mononuclear cells isolated from inflamed ileal mucosa of four Crohn's disease patients: 5.6 +/- 1.2; 3.2 +/- 1.9 and 2.4 +/- 1.4 (mean +/- SE) ng/1 X 10(6) cells were significantly higher than their respective synthesis by cultured mononuclear cells isolated from uninflamed ileal mucosa isolated from the same patients: 0.8 +/- 0.1; 0.3 +/- 0.1 and 0.2 +/- 0.03 ng/1 X 10(6) cells or from normal colonic mucosa: 1.5 +/- 0.3; 0.3 +/- 0.1 and 0.5 +/- 0.1 (N = 12) ng/1 X 10(6) cells. Prostanoid synthesis by primary cultures of intestinal mononuclear cells isolated from colonic mucosa of five ulcerative colitis patients was enhanced but not significantly different from its synthesis by cells isolated from normal subjects. These results suggest that the enhanced intestinal prostanoid synthesis in active Crohn's disease is derived from stimulated local mononuclear cells and may have an important role in the pathogenesis of the disease.     

Increased expression of VEGF and CD146 in patients with inflammatory bowel disease

BACKGROUND: Angiogenesis has been suggested as an integral part of inflammatory bowel disease pathology. Vascular endothelial growth factor has long been considered to play a central, specific role in angiogenesis. Endothelial junction adhesion molecules, such as CD146, have recently been suggested to play a potent role in angiogenesis. CD34 is expressed on vascular endothelium, and it has been reported to be upregulated on endothelium in IBD. We investigated the expression of tissue vascular endothelial growth factor, CD34 and CD146 in the inflamed mucosa of patients with active inflammatory bowel disease compared with no inflamed mucosa of healthy controls. METHODS: Forty-two IBD patients [23 ulcerative colitis, 19 Crohn's disease] and ten healthy controls were included in the study. In colonoscopically obtained biopsies, CD34, CD146 and vascular endothelial growth factor expression were evaluated by immunohistochemistry. RESULTS: Vascular endothelial growth factor was detected in the mucosa of all groups, and its expression was significantly higher in both Crohn's disease and ulcerative colitis compared with controls (p<0.05). Immunohistochemical staining for CD146 in the inflamed mucosa was significantly higher in both Crohn's disease and ulcerative colitis compared with controls (p=0.002). A trend of higher CD34 expression in Crohn's disease and ulcerative colitis compared with controls was also found, but the difference among the three groups was not statistically significant (p=0.09). CONCLUSIONS: Inflamed mucosa of patients with active Crohn's disease and ulcerative colitis showed a markedly enhanced expression of VEGF and CD146, than normal mucosa of controls, indicating a possible role of angiogenesis in the pathogenesis of inflammatory bowel disease.     

Role of interleukin 1 in inflammatory bowel disease--enhanced production during active disease.

Interleukin 1 is a polypeptide cytokine produced by various cell types and has been shown to have a major role in inflammatory and immunological responses. In experimental colitis it proved to be a dominant mediator and a reliable marker of inflammation. The aim of the present study was to determine in vitro the extent of production and release of interleukin 1 from colonic mucosa of patients with active untreated inflammatory bowel disease. Colonic mucosal biopsy specimens were obtained during colonoscopy from 17 patients with ulcerative colitis, eight patients with Crohn's disease of the colon, and 16 normal control subjects. Interleukin 1 content was determined in fresh and 24 hour organ cultured mucosa as well as in cultured medium. Interleukin 1 content and release were significantly higher in the inflamed mucosa compared with that of control subjects. Prednisolone inhibited interleukin 1 release in a dose dependent fashion. We conclude that colonic mucosal interleukin 1 content and production is significantly raised in active inflammatory bowel disease and may have a role in the pathogenesis of the inflammatory response. Pharmacological suppression of tissue interleukin 1 production may have a beneficial therapeutic effect.     

Increased Nitric Oxide Production and Inducible Nitric Oxide Synthase Activity in Colonic Mucosa of Patients with Active Ulcerative Colitis and Crohn's Disease

It is postulated that an enhanced production ofnitric oxide by inflamed intestine plays a role in thepathophysiology of active inflammatory bowel disease. Inthis study, systemic NO_x concentrations and colonic nitric oxide synthase activity weredetermined in patients with ulcerative colitis orCrohn's disease. The relationship between these twoparameters and disease activity, as well as differences in nitric oxide synthase activity betweenulcerative colitis and Crohn's disease, were areas ofspecific focus. Patients with active ulcerative colitisand Crohn's disease had significantly elevated plasma NO_x concentrations; a positivecorrelation was found between NO_x values andinducible nitric oxide synthase activities in the activemucosa of these patients. In active ulcerative colitis,levels of inducible nitric oxide synthase were significantlyelevated in both normal and inflamed mucosa, althoughinducible nitric oxide synthase activity was higher inthe latter. These colonic inducible nitric oxidesynthase activities correlated well with the results ofendoscopic and histologic grading of inflammation. Therewas no increase in constitutive nitric oxide synthaseactivity in patients with active ulcerative colitis. However, constitutive nitric oxidesynthase activity was significantly increased in theinflamed mucosa in patients with Crohn's disease. InCrohn's disease, elevated inducible nitric oxidesynthase activity was found in both normal and inflamedmucosa, with no significant difference between thetissues. Such differences in nitric oxide production inthe colonic mucosa possibly reflect the significant differences in the pathophysiology andcharacteristic clinical features between ulcerativecolitis and Crohn's disease.     

Increased mucosal matrix metalloproteinase-1, -2, -3 and -9 activity in patients with inflammatory bowel disease and the relation with Crohn''s disease phenotype

BACKGROUND AND OBJECTIVE: Matrix metalloproteinases are associated with matrix turnover in both physiological and pathological conditions. We postulate an association between aberrant matrix metalloproteinases proteolytic activity and the intestinal tissue destruction, seen in patients with Crohn's disease and/or ulcerative colitis. MATERIALS AND METHODS: Surgically resected inflamed and non-inflamed ileum and colon with/without extensive fibrosis from 122 Crohn's disease, 20 ulcerative colitis and 62 control patients were homogenized. Protein levels of matrix metalloproteinases and tissue inhibitor of metalloproteinases were measured by enzyme-linked immunosorbent assays (ELISA), while matrix metalloproteinases and myeloperoxidase activity were measured by specific activity assays. RESULTS: Expression of total levels of matrix metalloproteinases-1, -2, -3 and -9 relative to tissue inhibitor of metalloproteinases-1 and -2 was increased in inflamed inflammatory bowel disease compared to non-inflamed inflammatory bowel disease and control intestinal mucosa. Also, net matrix metalloproteinases-1, -2, -3 and -9 activity in inflamed inflammatory bowel disease was increased, with similar expression profiles in Crohn's disease and ulcerative colitis. Within inflamed inflammatory bowel disease, a close correlation of matrix metalloproteinases with myeloperoxidase was observed. The expression of matrix metalloproteinases and tissue inhibitor of metalloproteinases was similar in inflamed Crohn's disease tissue with or without extensive fibrosis and not related to fistulizing disease. CONCLUSIONS: We have shown increased net matrix metalloproteinases activity in intestinal inflammatory bowel disease tissue, likely to contribute to the tissue damage and remodelling seen in inflammatory bowel disease.     

Ectopic colonic mucosa in ulcerative colitis and in Crohn's disease of the colon

Colectomy specimens from 62 patients (22 with ulcerative colitis, 20 with Crohn's disease of the colon, and 20 with invasive adenocarcinoma [without inflammatory bowel disease]) were reviewed for the presence of ectopic colonic mucosa. One or more foci of ectopic colonic mucosa were found in 16 of the 22 specimens (72 per cent) with ulcerative colitis and in 11 of the 20 specimens (55 per cent) with Crohn's disease of the colon. None of the 20 specimens having adenocarcinoma (without chronic inflammatory bowel disease) had ectopic colonic epithelium. The presence of ectopic colonic mucosa was found to be dependent on the age of the patients (more frequent among younger patients) and on the number of sections per specimen. One adenocarcinoma in a case of long-standing ulcerative colitis had apparently originated in ectopic colonic mucosa. This study was supported by grants from the Karolinska Institute.     

Increased group II phospholipase A2 in colonic mucosa of patients with Crohn's disease and ulcerative colitis.

The immunochemical protein content of group II phospholipase A2 (PLA2) and PLA2 enzymatic activity were measured for colonic mucosal biopsy samples obtained from patients with either Crohn's disease of the colon or ulcerative colitis, and control patients without inflammatory bowel disease. Immunoreactive group II PLA2 (IR-PLA2 II) content and PLA2 activity in actively inflamed colonic mucosa of Crohn's disease patients were significantly higher than those in inactively inflamed mucosa of Crohn's disease patients and the colonic mucosa of controls. IR-PLA2 II content and PLA2 activity in severely inflamed mucosa of ulcerative colitis patients were significantly higher than those in the colonic mucosa of the controls. Mucosal PLA2 enzymatic activity was closely correlated with mucosal IR-PLA2 II content in patients with Crohn's disease and ulcerative colitis. These results suggest that an increase in PLA2 enzymatic activity in inflamed colonic mucosa of Crohn's disease and ulcerative colitis was mainly attributed to increased protein content of group II PLA2, and that an increase in mucosal group II PLA2 may be involved in the pathogenesis of intestinal inflammation of Crohn's disease and ulcerative colitis.     

Decrease in two intestinal copper/zinc containing proteins with antioxidant function in inflammatory bowel disease.

Oxygen derived radicals contribute to tissue injury in inflammatory bowel disease. We measured the content of superoxide dismutase and metallothionein (two endogenous copper and zinc containing proteins involved in radical scavenging) in intestinal resection specimens from 29 patients with Crohn's disease and 12 patients with ulcerative colitis and compared the concentrations with those obtained in the normal mucosa of a control group of 18 patients with colorectal cancer. The superoxide dismutase content was similar in control mucosa and non-inflamed mucosa from patients with inflammatory bowel disease (mean (SEM) 2.13 (0.10) and 2.24 (0.10) mg/g protein, respectively) but was decreased in inflamed mucosa (1.87 (0.08) mg/g protein, p less than 0.005 v non-inflamed mucosa). The metallothionein content was decreased in non-inflamed inflammatory bowel disease mucosa compared with control mucosa (0.23 (0.03) and 0.36 (0.04) mg/g protein, respectively, p less than 0.02) and a further decrease was found in inflamed mucosa (0.17 (0.02) mg/g protein, p less than 0.001 v control mucosa). No differences were found between Crohn's disease and ulcerative colitis and no significant effect of medication or tissue localisation was noted. These findings might indicate a decreased endogenous intestinal protection against oxygen derived radicals in inflammatory bowel disease which could contribute to the pathogenesis of the disease.