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.     

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.     

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.     

Vascular endothelial growth factor in inflammatory bowel disease

BACKGROUND AND AIMS: Angiogenesis is an important component of tissue regeneration. As Inflammatory bowel disease (IBD) involves inflammation, ulceration, and regeneration of the intestinal mucosa, angiogenesis may be an integral part of IBD pathology. This study investigated the role of vascular endothelial growth factor in IBD. PATIENTS AND METHODS: The VEGF plasma (pVEGF) and serum (sVEGF) levels were assessed in patients with ulcerative colitis (UC; n=50) or Crohn's disease (CD; n=44) and in healthy controls (n=23). The immunohistochemical expression of VEGF was also assessed in surgical material from 11 patients with active IBD. RESULTS. Overall the sVEGF levels ranged from 30-899 pg/ml (median 200 pg/ml) and were significantly higher than the pVEGF levels (range 20-80 pg/ml, median 30 pg/ml). pVEGF levels were significantly lower in patients with active and quiescent CD than in healthy controls. Despite the lower pVEGF levels noted also for patients with UC, the difference was not significant. sVEGF levels were also reduced in patients with IBD, but the difference was not significant. No association of pEGF/sVEGF with beta-thromboglobulin and platelet factor 4 levels (markers of platelet activation) was noted. On immunohistochemistry VEGF was not expressed in the inflammatory component (lymphocytes and macrophages), the fibroblasts, or the muscular layer of the intestinal wall. The intestinal epithelium was negative in CD, while a cytoplasmic reactivity was noted in UC and normal controls. CONCLUSION. As VEGF is a vascular and epithelial cell survival factor, the defective VEGF response ability, confirmed here for patients with CD, may be a key element in the pathology of the disease. The pathology of UC, however, seems not to be VEGF dependent.     

The role of vascular endothelial growth factor (VEGF) in inflammatory bowel disease

BACKGROUND: Vascular endothelial growth factor (VEGF) is a candidate susceptibility gene to inflammatory bowel disease (IBD), both from a functional as well as genetic perspective. Moreover, serum VEGF (sVEGF) levels are increased in IBD and correlate with disease activity. Both VEGF expression and sVEGF levels may be influenced by VEGF gene polymorphisms. AIMS: To study VEGF polymorphisms in IBD susceptibility and their impact on sVEGF levels. METHODS: Four functional VEGF polymorphisms (-C2578A, -G1154A, -G634C, and C936T) were genotyped in two independent cohorts (cohort 1: 372 IBD trios; cohort 2: 452 unrelated IBD patients, 271 healthy controls [HC]; and 93 patients with non-IBD gastrointestinal inflammation [non-IBD GI]), using polymerase chain reaction with restriction fragment length polymorphism and TaqMan minor groove binding. Phenotypical data on all patients as well as sVEGF levels were correlated with the genetic data. RESULTS: Both the VEGF genotype and haplotype frequencies did not differ between IBD patients and controls, and no distortion of transmission was observed. sVEGF levels were increased in IBD but also in non-IBD GI patients, compared with HC, and were only influenced by VEGF polymorphisms in patients with Crohn's disease (-G1154A genotype and -2578/-1154/-634 AAG promoter haplotype). CONCLUSIONS: The VEGF polymorphisms studied are not implicated in susceptibility to IBD and do not predict sVEGF levels. Although increased sVEGF and angiogenesis are important features of IBD, they do not appear genetically determined.     

Increased interleukin 8 expression in the colon mucosa of patients with inflammatory bowel disease.

To test whether there is a difference in the expression of interleukin 8 (IL8) between Crohn's disease and ulcerative colitis and to determine the main site of its synthesis this study analysed IL8 in mucosal biopsy specimens of patients with Crohn's disease and ulcerative colitis by enzyme linked immunosorbent assay (ELISA) and by in situ hybridisation. IL8 was measured by ELISA in 38 normal control patients, eight inflammatory control patients, 55 Crohn's disease biopsy specimens (26 patients), and 67 ulcerative colitis biopsy specimens (35 patients). IL8 mRNA was determined in samples by in situ hybridisation using a specific IL8 RNA probe. IL8 protein was significantly increased in macroscopically inflamed specimens of Crohn's disease (median 118 pg/specimen, p < 0.0001), ulcerative colitis (median 140 pg/specimen, p < 0.001), and inflammatory controls (median 30 pg/specimen, p = 0.010) compared with normal controls (median 4 pg/specimen). IL8 was also increased in uninflamed specimens of Crohn's disease (median 46 pg/specimen, p < 0.001) but not of ulcerative colitis patients (median 9 pg/specimen, p = 0.3). IL8 protein in the mucosa correlated significantly with macroscopic inflammation in Crohn's disease (r = 0.47, p < 0.001) and in ulcerative colitis (r = 0.60, p < 0.001). IL8 mRNA was detected by in situ hybridisation in 31 of 55 biopsy specimens (56%) of Crohn's disease patients, in 38 of 67 specimens of ulcerative colitis patients (57%), in five of eight inflammatory controls (63%) and in five of 38 normal controls (13%). Mucosal IL8 mRNA expression correlated with mucosal IL8 protein (r = 0.46, p < 0.001). IL8 mRNA was only detected in inflammatory cells of the interstitium but not in mucosal epithelial cells. IL8 is produced mainly in the lamina propria of the colon in inflammatory bowel disease and correlates with mucosal inflammation.     

Lymphocyte subpopulations of intestinal mucosa in inflammatory bowel disease.

Lymphocyte subpopulations in peripheral blood (PBL) and intestinal mucosa (IML) of 10 patients with inflammatory bowel disease (IBD) were compared with those of 11 non-IBD controls. PBL were separated on Ficoll/hypaque gradients, and IML were isolated by incubation in dithiothreitol, EDTA, and collagenase. These methods yielded cells of good viability and with intact HLA A and B-antigens. T-cells, identified by neuraminidase-treated sheep RBC rosettes and non-specific esterase staining, comprised approximately 91% of the IML from normal mucosa of all groups. B-cells, identified by erythrocyte-antibody-complement rosettes and surface immunoglobulins, were only 7% of these IML populations. Cell yields were two-fold or more greater from abnormal IBD mucosa, with T-cells ranging from 55 to 95% and B-cells from 2 to 36%. The percentage of Fc receptor bearing cells was low in all specimens. By these methods, T-lymphocytes predominated in intestinal mucosa of both IBD and non-IBD patients, but there is marked increase in the percentage of B-cells isolated from abnormal mucosa in IBD.     

Expression of platelet-derived endothelial cell growth factor in inflammatory bowel disease

Background: Platelet-derived endothelial cell growth factor (PD-ECGF) is reported to be highly expressed in tumors and inflammatory tissues, but its expression and role in inflammatory bowel disease (IBD) are still unclear. In this study we examined the location and tissue density of cells immunoreactive for PD-ECGF in the colonic mucosa of IBD. Methods: Paraffin-embedded sections of colonic tissue from patients with ulcerative colitis (UC) or Crohn's disease (CD) were immunostained for PD-ECGF. As controls, noninflamed mucosa of IBD, as well as normal colonic mucosa from patients with colorectal cancer, were used. Also, cancer tissues were evaluated. In addition, changes in the expression of PD-ECGF in human umbilical vein endothelial cells (HUVEC) after treatment with inflammatory cytokines and angiogenic factors, as well as after coculture with colon cancer cell lines, were evaluated by flow cytometry. Results: In normal colonic mucosa and noninflamed mucosa of IBD, PD-ECGF expression was negligible. In inflamed colonic mucosa, strong expression was observed, predominantly in macrophages and fibroblasts. Vascular endothelial cells of the inflamed colonic mucosa, but not of normal colonic mucosa or of neoplastic tissues, stained for PD-ECGF, and the microvessel density was significantly increased in the severely inflamed mucosa. Flow cytometry demonstrated that PD-ECGF was constitutively expressed in HUVEC. Inflammatory cytokines and vascular endothelial growth factor (VEGF) increased its expression, whereas basic fibroblast growth factor (bFGF) decreased it. Coculture with colon cancer cell lines in direct contact, but not in those without contact, also resulted in an important decrease in the expression of PD-ECGF in HUVEC. Conclusions: Autocrine production of PD-ECGF by endothelial cells may be a mechanism of inflammatory angiogenesis, but not tumor angiogenesis, and may be particularly important for the maintenance of damaged vasculature in IBD. Received: September 17, 2001 / Accepted: September 6, 2002 Acknowledgments. This study was supported partly by a Grant-in-Aid for Scientific Research from the Ministry of Education, Culture, Sports, Science, and Technology of Japan, and partly by a grant from the Ministry of Health, Labour, and Welfare of Japan. Reprint requests to: S. Saito, Present address: Department of Surgery, Chigasaki Municipal Hospital, 5-15-1 Honson, Chigasaki 253-0042, Japan     

Cytokine production in patients with inflammatory bowel disease.

The production of cytokines in peripheral blood mononuclear leukocytes of patients with inflammatory bowel disease was investigated. T cell subset analysis and differential white blood cell counts were also performed. Thirty five patients with ulcerative colitis, 14 with Crohn's disease, and 15 age matched healthy volunteers were studied. No differences were observed in T cell subsets and OKT4/OKT8 ratios in patients with ulcerative colitis or Crohn's disease compared with controls. Interleukin 1 beta production was significantly increased in active ulcerative colitis and Crohn's disease, compared with values in controls, but returned to control levels in the inactive stages. In addition, in active ulcerative colitis and Crohn's disease, there were significant correlations between the interleukin 1 beta production and the ulcerative colitis activity index or Crohn's disease activity index. Interleukin 2 production was also significantly increased in the active ulcerative colitis and significantly correlated to the activity index, but there was no change in Crohn's disease patients compared with controls. Gamma interferon production in patients was the same as that in controls. This study suggests that the interleukin 1 beta and 2 values in peripheral mononuclear leukocytes of active untreated inflammatory bowel disease are indicators of the disease states of ulcerative colitis or Crohn's disease, or both.     

Increased production of vascular endothelial growth factor in peritoneal macrophages of cirrhotic patients with spontaneous bacterial peritonitis

Spontaneous bacterial peritonitis (SBP) is a common complication of cirrhotic patients with ascites that usually results in renal failure and death despite the efficacy of the current antibiotic therapy. The pathogenesis of these phenomena is poorly known but it has been related to the production of vasoactive cell mediators locally acting on the splanchnic vasculature. Because previous studies showed that peritoneal macrophages of cirrhotic patients may produce high quantities of vascular endothelial growth factor (VEGF), a powerful vessel permeabilizing agent, when stimulated by cytokines and bacterial lipopolysaccharide, the present study was aimed to seek whether peritoneal macrophages of SBP patients are induced to produce increased amounts of VEGF. Our results indicate that the production rate and the messenger RNA (mRNA) and protein expression of this substance are increased in macrophages of patients with SBP in comparison with those of noninfected cirrhotic patients. This characteristic feature is absent in circulating monocytes of these patients. Moreover, enhanced endothelial cell proliferation induced by conditioned medium of macrophages isolated from the ascites of patients with SBP is abolished by anti-VEGF antibody, and peritoneal tissue of cirrhotic patients expresses both VEGF receptors, Flt-1 and KDR. These results, therefore, are consistent with the concept that locally released macrophage-derived VEGF may result in increased vascular permeability and plasma leakage in the peritoneal vessels of cirrhotic patients with SBP.     

IL-27在炎症性肠病炎症肠黏膜中的表达及意义

目的:检测克罗恩病(CD)和溃疡性结肠炎(UC)肠黏膜组织中IL-27 p28 mRNATL其蛋白、IL-27受体mRNA的表达,探讨其在CD和UC中的发病意义.方法:应用反转录-聚合酶链反应(RT-PCR)和蛋白质免疫印迹(Western blot)方法检测炎症性肠病患者炎症肠黏膜组织中IL-27 p28基因及蛋白、IL-27受体基因的表达,并与健康者作对照.结果:IL-27 p28 mRNA在CD患者中的阳性率和灰度分析表达较UC患者明显增高(X2=6.64,P<0.05;t=11.01,P<0.01),IL-27受体阳性率和灰度分析在CD患者较UC患者和健康对照者明显增高(阳性率:X2=10.91,P<0.016,X2=18.84,P<0.016).IL-27蛋白阳性率和灰度分析在CD患者中表达明显高于UC患者(X2=5.24,P<0.05;t=3.37,P<0.05),并且IL-27mRNA的表达与蛋白质表达密切相关.结论:IL-27 p28及其受体的上调,可能有助于CD患者炎症发展过程.     

Increased vascular endothelial growth factor in acute eosinophilic pneumonia.

Acute eosinophilic pneumonia (AEP) is associated with the presence of diffuse pulmonary infiltrates on the chest radiograph and an increased number of eosinophils and an elevation of interleukin (IL)-5 levels in bronchoalveolar lavage (BAL) fluid. Vascular endothelial growth factor (VEGF) is a constitutively expressed protein encoded by messenger ribonucleic acid in human eosinophils and is released following stimulation with IL-5. However, the roles of IL-5 and VEGF in the pathogenesis or activity of this disease have not been clarified. The authors investigated the cells and the levels of these two factors in BAL fluid in five AEP patients and five normal controls before and after corticosteroid treatment. The absolute number of eosinophils-mL(-1), IL-5 and VEGF levels in patients before treatment were higher than in controls (53.8 versus 0.3 x 10(4) x mL(-1), 490.1 versus 5.2 pg x mL(-1) and 643.0 versus 133.9 pg x mL(-1), respectively). IL-5 and VEGF rapidly decreased to the control level in parallel with clinical improvement. The relationship between eosinophilia and IL-5 and VEGF levels was strongly significant. Elevated interleukin-5 in the lung may initiate the recruitment of eosinophils and enhance the release of mediators, such as vascular endothelial growth factor from eosinophils, which, in turn, increases the permeability of blood vessels.     

Increased blood vascular endothelial growth factor levels in patients with acute myocardial infarction

Vascular endothelial growth factor (VEGF) is a growth factor for vascular endothelial cells in vitro. The present study was designed to determine whether serum VEGF levels increase in patients with acute myocardial infarction (AMI) compared with patients with stable exertional angina and control subjects, and to examine the serial changes of serum VEGF levels in patients with AMI. We examined serum VEGF levels by using antibody prepared from serum immunized with human VEGF(121). The serum VEGF level (pg/ml) was higher (p < 0. 0001) on admission in the patients with AMI (177 +/- 19) than in those with stable exertional angina (61 +/- 7) and control subjects (62 +/- 6). The serum VEGF level (pg/ml) of the patients with AMI was 177 +/- 19 on admission, 125 +/- 9 on day 3, 137 +/- 11 on day 5, 242 +/- 18 at 1 week, and 258 +/- 22 at 2 weeks after admission. The value was higher on admission than on day 3 after admission (p = 0.014), the values were higher at 1 week and 2 weeks than on admission, on day 3, and 5 (p < 0.01). Furthermore, there were correlations between peak VEGF levels at 1 week or 2 weeks after admission and peak creatine kinase levels. The increase of VEGF on admission in the patients with AMI may be due to the hypoxia of acute myocardial ischemia. The elevation at 1 week and 2 weeks from the onset may cause the development of collateral circulation in relation to the healing of the infarction site.     

Enhanced leukocyte binding by intestinal microvascular endothelial cells in inflammatory bowel disease

BACKGROUND & AIMS: Microvascular endothelial cells mediate leukocyte homing, angiogenesis, and inflammation and healing and show tissue- specific adhesion molecules and functions. The activation of human intestinal mucosal microvascular endothelial cells (HIMECs) was studied in vitro to uncover possible abnormalities associated with inflammatory bowel disease. METHODS: HIMECs were isolated from normal and inflammatory bowel disease mucosa and assessed for phenotypic and morphological features, proliferative response, leukocyte binding capacity, and adhesion molecule expression. RESULTS: Basal proliferation by HIMECs was less than that of human umbilical vein endothelial cells (HUVECs) but increased proportionally more in response to vascular endothelial growth factor. Proinflammatory stimuli induced an activated, spindle-shaped morphology in HIMEC monolayers. Compared with HUVECs, unstimulated HIMECs showed less adhesiveness for U937 and MOLT4 cells and neutrophils, but cytokines and lipopolysaccharide substantially increased the binding capacity of HIMECs. HIMECs derived from inflammatory bowel disease mucosa showed a markedly greater leukocyte-binding capacity than normal mucosal HIMECs. Patterns of intercellular adhesion molecule 1, vascular cell adhesion molecule 1 and E-selectin messenger RNA expression were distinct in HIMECs, HUVECs, and mucosal mesenchymal cells. CONCLUSIONS: HIMECs represent differentiated endothelial cells with unique functional properties. Their dramatically enhanced capacity to bind leukocytes in inflammatory bowel disease suggests that HIMECs play an important role in initiating or maintaining inflammation. (Gastroenterology 1997 Jun;112(6):1895-907)     

Increased circulating vascular endothelial growth factor is correlated with disease activity in polyarticular juvenile rheumatoid arthritis.

OBJECTIVE: To investigate the relevance of vascular endothelial growth factor (VEGF) in the pathogenesis of juvenile rheumatoid arthritis (JRA). METHODS: Serum VEGF levels in 58 patients with JRA (systemic in 17, polyarticular in 29, pauciarticular in 12) were measured by ELISA and compared with those of 21 patients with infectious diseases and 50 healthy children. Correlations of VEGF levels with number of joints with active arthritis, erythrocyte sedimentation rate (ESR), and hyaluronic acid (HA) were examined. RESULTS: Serum levels of VEGF in patients with JRA were significantly higher than in healthy controls. Patients with systemic and polyarticular JRA showed statistically higher levels of VEGF than those with infectious diseases. VEGF levels correlated statistically with C-reactive protein (CRP) in patients with both infectious diseases and polyarticular JRA, but the regression slope (VEGF/CRP) was much steeper in polyarticular JRA than in infectious diseases. Serum VEGF levels correlated with disease activity variables such as the number of joints with active arthritis, ESR, and serum HA levels in polyarticular JRA. CONCLUSION: The correlation of serum VEGF levels and disease activity in polyarticular JRA suggests that VEGF may take an active part in joint inflammation.     

炎症性肠病与肠黏膜免疫调节细胞

炎症性肠病(innammatory bowel disease,IBD)包括克罗恩痛(Crohn's disease,CD)和溃疡性结肠炎(ulcerative colitis,UC).其病因和发病机制尚未完全明确,免疫功能紊乱被认为是一重要因素,肠黏膜免疫调节细胞和多种细胞因子参与免疫反应和炎症过程.是当前关于IBD免疫发病机制的研究热点之一.本文仅此作一简要综述.     

Transepithelial transport processes at the intestinal mucosa in inflammatory bowel disease

Crohn's disease (CD) and ulcerative colitis (UC) are inflammatory bowel diseases (IBD) of unknown etiology. Oral absorption studies have shown an increased intestinal permeability for various sugar molecules in patients with IBD and their healthy relatives as a possible pathogenetic factor. However, the various transport pathways through the mucosal barrier have not yet been examined. This study therefore investigated whether antigens pass the epithelial barrier by a transcellular or a paracellular pathway. Mucosa of freshly resected specimens from CD (n = 10) or UC (n = 10) patients was investigated by immunoelectron microscopy and compared with healthy mucosa. Epithelial transport was studied with the antigens ovalbumin and horseradish peroxidase after defined incubation. Labeling density of subunit c of ATP synthetase was determined in mitochondria of enterocytes of all specimens. In all specimens epithelial transport of OVA and HRP was principally transcellular through enterocytes with normal ultrastructure, although some tight junctions in CD and UC were dilated. Antigens were transported within vesicles to the basolateral membrane 2.5 min after incubation. The level of enterocytes with electron-lucent cytoplasm containing a high amount of antigens was higher in CD and UC than in healthy mucosa, depending on the grade of inflammation. ATP synthetase was significantly decreased in electron-lucent cytoplasm of CD and UC to normal ultrastructure of healthy mucosa. Our study shows that ovalbumin and horseradish peroxidase taken up by the apical membrane reach the paracellular space by vesicular transport in healthy and IBD enterocytes within a few minutes. Transcellular pathway is affected in both CD and UC, which is indicated by a high level of antigens within the cytosol. We speculate that increased intestinal permeability in IBD results substantially from enhanced transcellular transport. Accepted: 4 January 1999     

Microalbuminuria correlates with intestinal histopathological grading in patients with inflammatory bowel disease.

It has previously been shown that microalbuminuria is a useful disease activity marker for inflammatory bowel disease (IBD). Microalbuminuria correlates strongly with the markers of clinical and laboratory disease activity such as erythrocyte sedimentation rate (ESR), and C reactive protein (CRP). The aim of this study was to discover if microalbuminuria accurately reflects the intestinal inflammation by correlating it with intestinal inflammation using a standard histopathological grading system in patients with ulcerative colitis and Crohn's colitis. Forty two patients with IBD who had undergone endoscopic examination of the entire colon for the assessment of severity and extent of the disease (Crohn's colitis (n = 21), ulcerative colitis (n = 21)) were recruited to the study. Patients with small bowel Crohn's disease were not studied. Twenty four patients had left sided colonic disease and 18 patients had extensive colonic disease. Each patient's colonic biopsy specimens were scored blindly by a histopathologist and a composite score was compiled on the basis of the severity of changes in the enterocytes and crypts and the cellularity of the lamina propria. A clinical disease activity was obtained using the simple index of Harvey and Bradshaw. Microalbuminuria was measured in all patients by an immunoturbiditimetric method. ESR and CRP were also measured, as indicators of acute phase response in the same patients. It was found that patients with active IBD had higher concentrations of microalbuminuria compared with those patients in remission (median 222 micrograms/min (range 40-686 micrograms/min) v median 96 micrograms/min (range 30-376 micrograms/min); p < 0.001)). Significantly higher concentrations of microalbuminuria were also detected in patients with extensive colonic IBD compared with those patients with left sided disease (median 297 micrograms/min (range 132-686 micrograms/min) v median 101 micrograms/min (range 30-433 micrograms/min); p < 0.001)). A strong positive correlation was seen between microalbuminuria and intestinal histopathological score in IBD patient groups with left sided colitis (r = 0.77; p < 0.001) and extensive disease (r = 0.71; p < 0.01). The standard histopathological grading system correlated with the clinical disease activity (r = 0.64; p < 0.005) and CRP (r = 0.62; p < 0.02), however, it did not correlate with ESR. In conclusion, the strong correlation of microalbuminuria with a standard intestinal histopathological grading system suggests that microalbuminuria accurately reflects the severity of colonic inflammation in patients with Crohn's colitis and ulcerative colitis.