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The effect of angiotensin-converting enzyme inhibitors on experimental colitis in rats.

The present study was aimed to investigate the effect of ACE inhibition on trinitrobenzene sulphonic acid (TNBS)-induced colonic inflammation in rats by using captopril and lisinopril. In treatment groups, the rats were treated with ACE inhibitors, captopril or lisinopril (0.1 and 1 mg/kg/day; intraperitoneally). The drugs were given 5 min after induction of colitis and the treatment was continued for 3 days. Three days after the induction of colitis, all rats were decapitated. The distal colon was weighed and the mucosal lesions were scored at both macroscopical at microscopic levels. Malondialdehyde (MDA) and glutathione (GSH) levels, myeloperoxidase (MPO) activity and collagen content were assessed in tissue samples. Formation of reactive oxygen species in colonic samples was monitored by using chemiluminescence technique. Serum TNF-alphalevel was assessed in trunk blood. Captopril treatment was found to be beneficial in all parameters, except colonic glutathione content. On the other hand, although stimulation of lipid peroxidation and increase in serum TNF-alpha level were successfully prevented by lisinopril, the morphology of the lesions remained unchanged. In conclusion, sulphydryl and non-sulphydryl ACE inhibitors, captopril and lisinopril do not seem to be similarly effective in TNBS-induced colitis model at least at the doses tested in our study.

Angiotensin-Converting Enzyme Inhibitors↗

Effect of acute pentoxifylline treatment in an experimental model of colitis.

BACKGROUND: The effect of acute pentoxifylline treatment in an experimental model of colitis was assessed using the trinitrobenzene sulphonic acid (TNBS)-induced rat model of colitis. METHODS: Animals were treated with intracolonic injection (250 microliters) of TNBS (50 mg in 50% ethanol) to induce inflammation and ulcers. Animals received pentoxifilline (100 mg/kg intracolonically) or saline 24 and 48 h following TNBS treatment. Five days following TNBS treatment, colons were dissected and scored according to the morphology damage score. The colons were then rolled longitudinally, fixed in formalin and embedded in paraffin. The collagen content of colonic sections were determined by a Sirius red-Fast green technique. RESULTS: Animals treated with TNBS alone had significantly higher gross morphology damage scores compared to animals treated with saline. Pentoxifylline significantly reduced the gross morphology damage score in animals receiving TNBS. Colonic collagen levels were significantly elevated in TNBS-treated animals compared to animals receiving saline. Pentoxifylline treatment did not alter the collagen content of colons from TNBS-treated animals. CONCLUSION: TNBS treatment significantly elevates morphology damage score compared to controls. The results also suggest that colonic collagen was significantly elevated in animals treated with TNBS compared to controls. Pentoxifylline treatment was not sufficient to reduce the elevation in colonic collagen, although pentoxifylline treatment was sufficient to reduce the pathological changes due to TNBS, thus bringing the morphology damage score down to control levels.

Animals↗

Integrin alpha2beta1 regulates neutrophil recruitment and inflammatory activity in experimental colitis in mice.

BACKGROUND: Human inflammatory bowel disease (e.g., Crohn's disease and ulcerative colitis), is associated with leukocyte accumulation in the inflamed intestinal tissue. Recent studies strongly suggest a role of beta1 integrin receptors in regulating tissue damage and disease symptoms related to inflammatory bowel disease. The aim of this study was to investigate the role of the collagen-binding alpha2beta1 integrin (CD49b/CD29) in dextran sodium sulfate-induced colitis in mice. METHODS: Colitis was induced in mice through oral administration of 2% dextran sodium sulfate in drinking water. Rectal administration of anti-alpha2-monoclonal antibody (mAb) in 1 group was compared with oral treatment with betamethasone in another group and rectal administration of a control antibody in a third group. Clinical and histological signs of colitis, neutrophil infiltration into the colon mucosa, and gene expression of metalloproteinases were assessed. RESULTS: Rectal administration of anti-alpha2-mAb was found to significantly reduce weight loss from 13.5% +/- 6.5% to 2.2% +/- 0.2% (P = 0.013 versus control mAb) and mucosal neutrophil infiltration from 47.2 +/- 10.0 to 6.6 +/- 8.0 neutrophils per counted area (P < 0.05 versus control mAb). Metalloproteinase gene expression was suppressed through anti-alpha2-mAb treatment. The protective effect against colitis seen after anti-alpha2beta1 integrin treatment was found to be favorable to the effect seen after high-dose oral betamethasone. CONCLUSIONS: We demonstrate an alleviating action of the collagen-binding alpha2beta1 integrin in experimental colitis in mice and suggest that this effect is mediated by inhibition of neutrophil migration and activation. Local administration of function-blocking antibodies against integrin alpha2beta1 may provide novel avenues to treat inflammatory bowel disease.

Analysis of Variance↗

Effects of statins on experimental colitis in normocholesterolemic rats.

OBJECTIVE: The results of previous studies suggest that statins have a direct anti-inflammatory effect that is not directly related to their cholesterol-lowering activity. The aim of this study was to investigate the effect of simvastatin (SIM) and fluvastatin (FLU) on trinitrobenzene sulfonic acid (TNBS)-induced colonic inflammation in rats. MATERIAL AND METHODS: The drugs were given for 3 days (0.1 and 1 mg/kg day-1; intraperitoneally) after induction of colitis. The lesions in the distal colon were scored at the macroscopic and microscopic level. Tissue malondialdehyde (MDA) and glutathione (GSH) levels, myeloperoxidase (MPO) activity and collagen content were assessed and formation of reactive oxygen species and peroxynitrite was monitored by chemiluminescence (CL) assay. Trunk blood was collected for the measurement of serum tumor necrosis factor (TNF)-alpha level. RESULTS: Treatment with SIM reduced the lesion score of the colitis group at macroscopic level (p<0.05), but there was no effect of treatment with FLU. The increase in colonic MDA level of the colitis group was reduced by both drugs at all doses (p<0.05-0.001). The decrease in GSH and the an increase in MPO activity in the colitis group were reversed by SIM at all doses (p<0.01), but FLU had no effect. An increase in colonic lucigenin CL value in the colitis group was reduced by SIM and FLU at all doses (p<0.001) and an increase in peroxynitrite ratio in the colitis group showed a significant reduction in SIM-treated groups; FLU reduced this effect at a dose of 1 mg/kg (p<0.01). An increase in tissue collagen content and serum TNF-alpha level in the colitis group was reversed by both drugs at all doses (p<0.001). CONCLUSIONS: SIM and FLU seemed to be beneficial in a TNBS-induced rat colitis model through the prevention of lipid peroxidation, superoxide generation, cytokine production and neutrophil accumulation.

Animals↗

Design, expression, and renaturation of a lesion-targeted recombinant epidermal growth factor-von Willebrand factor fusion protein: efficacy in an animal model of experimental colitis.

In the present study, the mature epidermal growth factor (EGF) protein was engineered to incorporate a high affinity collagen-binding domain (CBD) derived from co-agulation von Willebrand factor, to specifically target EGF to colonic lesions. The fusion protein was expressed in an E. coli bacterial expression system, purified by metal chelate chromatography, and renatured by oxidative refolding into a soluble biologically active growth factor. The EGF-CBD fusion protein bound tightly to collagen matrices under conditions in which native non-targeted EGF was washed away. In biologic assays, the EGF-CBD fusion protein stimulated NIH3T3 cell proliferation with near wild-type biological activity. In vivo binding studies showed that the collagen-targeted EGF, but not the non-targeted EGF, accumulated at areas of exposed collagen on the luminal surface of the inflamed colon. Finally, a single colonic instillation of the collagen-targeted EGF-induced a more rapid regeneration of intestinal crypts 24 h after treatment (no. of crypts = 89.2+/-8.1) compared to the non-targeted EGF (no. of crypts = 52.2+/-29.8; p=0.027), and the PBS control (no. of crypts = 24. 0+/-22.9; p=0.001). Taken together, these findings indicate that intracolonic delivery of collagen-targeted EGF represents a potentially effective therapeutic strategy for acute or chronic inflammatory bowel disease.

3T3 Cells↗

A murine model of chronic inflammation-induced intestinal fibrosis down-regulated by antisense NF-kappa B.

BACKGROUND & AIMS: To elucidate extracellular matrix (ECM) changes underlying intestinal fibrosis, a frequent complication of inflammatory bowel disease, we developed a murine model of chronic colitis associated with intestinal fibrosis. METHODS: Chronic inflammation was established by weekly intrarectal administration of trinitrobenzene sulfonic acid (TNBS). In 2 variations of the model an antisense oligonucleotide for nuclear factor kappa B (NF-kappa B) p65 was given prophylactically or therapeutically to block chronic inflammation-associated fibrosis. Colonic inflammation and fibrosis were determined by histology. Total collagen level was estimated by hydroxyproline quantification. Colonic expression of collagens (Col1a2, Col3a2), ECM remodeling genes (matrix metalloproteinase [MMP]-1, -3, and tissue inhibitor of matrix metalloproteinase [TIMP]-1), and inflammation-modulating cytokines (tumor necrosis factor alpha [TNF-alpha], interferon gamma [IFN-gamma], transforming growth factor beta 1 [TGF-beta 1], and insulin-like growth factor 1 [IGF-1]) were assessed by semiquantitative reverse-transcription polymerase chain reaction. Control and TNBS-treated colonic mesenchymal cells were characterized by morphology, phenotype, and functional response to TNF-alpha and IFN-gamma. RESULTS: Colons of TNBS-treated mice contained acute and chronic inflammatory infiltrates, increased collagen, fibrogenic tissue architecture, and increased expression of TNF-alpha, TGF-beta 1, IGF-1, Col1a2, MMP-1, and TIMP-1. Colonic mesenchymal cells from TNBS-treated mice were also morphologically distinct from those of the control mice, with increased TIMP-1 expression in response to IFN-gamma treatment. Fibrosis persisted for 2-4 weeks after cessation of the TNBS treatment. In mice given NF-kappa B antisense prophylactically, 67% were fibrosis-free, whereas of those treated after establishing chronic inflammation, 43% were free of fibrosis. CONCLUSIONS: Extended TNBS treatment of mice yielded chronic intestinal inflammation-associated fibrosis with extensive fibrogenic ECM changes that could be counteracted by specific blockade of NF-kappa B.

Animals↗

Morphologic and morphometric analyses of acetic acid-induced colitis in rats after treatment with enemas from Myracrodruon urundeuva Fr. All. (Aroeira do Sertão).

The present work showed the effects of Myracrodruon urundeuva Fr. All., popularly known as 'aroeira' (AE), in the form of enemas prepared from the stem bark, on several morphologic and morphometric parameters after acetic acid-induced colitis in rats. Enemas from 5-ASA were used as standard while the vehicle, carboxymethylcellulose, was used as a control. The results of the morphological evaluation showed that on day 1 acetic acid produced significantly more necrosis in the groups treated with AE (10% and 20%) or 5-ASA than the controls. However, on day 60, there were more caliciform and absorptive cells in the treated groups compared with the controls. A significantly higher number of eosinophil and mononuclear cells and also collagen deposition in the controls compared with the treated groups were observed on day 60. However, a higher number of polymorphonuclear cells was detected on day 60 only in the AE treated group but not in the 5-ASA group. These data indicate that animals treated with AE or 5-ASA showed complete epithelial tissue regeneration, while in the controls chronic inflammatory exudate persisted and tissue regeneration occurred through fibrosis.

Acetic Acid↗

Colonic lymphocytosis in patients with celiac sprue.

We examined colonic biopsies from 39 patients with clinical and small bowel biopsy changes of celiac sprue. In 12 of 39 patients (31%), striking lymphocytic infiltration of the superficial colonic epithelium and chronic inflammation of the lamina propria were identified. These 12 cases had a mean of 30.4 lymphocytes per 100 superficial colonic epithelial cells, compared with means of 8.4 in sprue cases without colonic epithelial lymphocytosis, 4.8 in normal controls, and 32.4 in nine cases of lymphocytic colitis without concurrent celiac sprue. No case showed subepithelial collagen layer thickening. Four patients with celiac sprue and colonic lymphocytosis also had gastric biopsies; two showed gastric lymphocytosis. Intraepithelial lymphocytes at all sites were positive for the T-cell marker MT-1. These findings indicate that sprue-associated colonic lymphocytosis and lymphocytic colitis are histologically, quantitatively, and immunohistochemically indistinguishable, that the epithelial T-cell infiltration of celiac sprue occurs in glandular mucosa at all levels of the gastrointestinal tract, and that colonic subepithelial collagen deposition in patients with celiac sprue is an infrequent occurrence. These findings also suggest that gastrointestinal epithelial T-cell infiltration may be an immunologic response that is common in individuals sensitized to absorbed lumenal antigens, and that colonic lymphocytosis may occur as a response to a number of antigens, including gluten.

Celiac Disease↗

Serum aminoterminal propeptide of type III procollagen (S-PIIINP) and hepatobiliary dysfunction in patients with ulcerative colitis.

The aim of the study was to estimate the usefulness of measuring the circulating concentration of serum aminoterminal propeptide of type III collagen (S-PIIINP) in screening for hepatobiliary diseases in patients with ulcerative colitis. S-PIIINP was measured in 69 patients with ulcerative colitis and normal liver biochemistry, in 14 patients with ulcerative colitis and elevated catalytic concentration of alkaline phosphatases in serum (S-ALP, EC 3.1.3.1) but without primary sclerosing cholangitis (PSC), and in 20 patients with ulcerative colitis and PSC. The median S-PIIINP was 3.1 micrograms l-1 in patients with ulcerative colitis and normal liver biochemistry, 4.3 micrograms l-1 in patients with ulcerative colitis and hepatobiliary disorder other than PSC and 8.9 micrograms l-1 in those with ulcerative colitis and PSC. When the S-PIIINP cut-off level was set at 5.0 micrograms l-1, 1% of the patients with ulcerative colitis and normal liver biochemistry, 21% of those with hepatobiliary disorder, not PSC, and 90% of the patients with PSC had S-PIIINP values above that concentration. In conclusion, S-PIIINP above 5.0 micrograms l-1 in a patient with ulcerative colitis strongly suggests concomitant PSC.

Adolescent↗

[Procollagen-III-peptide in the serum of patients with Crohn disease].

Serum procollagen-III-peptide (PP III) concentrations were measured in 54 patients with Crohn's disease and compared with data obtained from healthy controls and patients with liver fibrosis or ulcerative colitis. Whereas in alcoholic liver cirrhosis and chronic active hepatitis PP III was increased up to 18-fold as described by others, only 3 patients with Crohn's disease had slightly elevated PP III concentrations. In 2 of them, increased PP III could be explained by adolescence. In 5 other patients, PP III levels were at the upper limit of normal. Subgroup analysis showed that high clinical disease activity, recurrence after intestinal resection, presence of strictures and long disease duration did not elevate PP III levels. We therefore conclude that determination of serum PP III is of no value in the follow-up patients with Crohn's disease. In ulcerative colitis, PP III levels were uniformly normal. An additional result was a decreased PP III during corticosteroid therapy, suggesting a direct effect on collagen metabolism.

Adult↗

Collagen components in the duodenal and rectal mucosa in progressive systemic sclerosis and other diseases.

Small intestinal mucosa from 14 patients suffering from progressive systemic sclerosis and 22 patients with various other diseases was analysed for collagen components. There was no significant difference in the concentration of hydroxyproline, hydroxylysine and proline between the two groups. Rectal mucosa from 11 progressive systemic sclerosis patients, 5 patients with ulcerative colitis and 7 patients with various other diseases was analysed for collagen components. No significant difference was demonstrated in the concentration of hydroxyproline, hydroxylysine and proline between progressive systemic sclerosis patients and patients with various other diseases, but in patients with ulcerative colitis the concentration of hydroxyproline, hydroxylysine and proline were found to be significantly lower than in the two other groups.

Adolescent↗

Stricture formation in Crohn's disease: the role of intestinal fibroblasts.

OBJECTIVE: To determine whether intestinal fibroblasts in patients with Crohn's disease (CD) have an enhanced capacity to reorganize collagen and thus cause stricture formation. SUMMARY BACKGROUND DATA: Stricture formation is a characteristic feature of CD that may distinguish it from other forms of inflammatory bowel disease. Methods Fibroblasts were obtained at surgery from the colon and ileum of patients with CD and ulcerative colitis (UC) and control patients. Primary fibroblast cultures were obtained by explant technique. Fibroblast contractile activity was measured using fibroblast-populated collagen lattices (FPCLs), in which the cultured fibroblasts were seeded in free-floating collagen gel matrices that they reorganize and contract. Fibroblast contractile activity was measured as the reduction of surface area (mm2) of collagen gel matrix at 24-hour intervals for 1 week. RESULTS: Fibroblasts from patients with CD displayed enhanced capacity to contract FPCL when compared to UC and control fibroblasts. This activity was maximal in fibroblasts recovered from strictured regions in CD. Fibroblasts from patients with UC had a contractile capacity similar to that of controls. Hydrocortisone inhibited this in vitro contractile activity in a dose-dependent manner. CONCLUSIONS: Intestinal fibroblasts in CD possess enhanced capacity for collagen reorganization and contractile activity in vitro. This activity may be responsible for stricture formation in CD.

Cell Line↗

Suspicion of microscopic colitis raised by sonographic examination.

This report describes the case of a 57-year-old woman who was incidentally identified as having lymphocytic colitis after she underwent routine transabdominal sonographic examination. She initially reported having no irregularities in her bowel movements. Sonography revealed the following nonspecific findings: watery stool in the entire colon, slight thickening of the hypoechoic mucosal layer and moderate thickening of the hyperechoic submucosal layer of the colon, and no pathologic findings in the small intestine. On additional questioning, the patient said that she had had watery diarrhea for the last 10 years, with as many as 10 bowel movements daily. Endoscopic examination and biopsy were performed. Histopathologic examination of biopsy specimens showed lymphocytic infiltration of the mucosa and some collagen deposits, consistent with a diagnosis of lymphocytic colitis. Treatment was begun with loperamide, sulfasalazine, and budesonide. Within 3 weeks of the start of treatment, the number of bowel movements decreased to 1-2 daily. Follow-up sonography at that time revealed normalization of the bowel contents and disappearance of the thickened submucosal layer of the colon. Nonspecific sonographic findings like those in this case lead to the need to rule out various diseases through further appropriate evaluations to identify the correct diagnosis.

Anti-Inflammatory Agents↗

Altered levels of biochemical indices of bone turnover and bone-related vitamins in patients with Crohn's disease and ulcerative colitis.

BACKGROUND: The pathogenesis of inflammatory bowel disease-associated osteopenia may be related to pathological rates of bone turnover; however, the literature shows mixed results. AIM: To compare bone biomarkers in inflammatory bowel disease patients (Crohn's disease: n = 68, and ulcerative colitis: n = 32, separately) with age- and sex-matched healthy controls. SUBJECTS: Patients and controls were recruited from Cork University Hospital and Cork City area, respectively. RESULTS: Relative to that in their respective controls, Crohn's disease (n = 47) and ulcerative colitis (n = 26) patients (i.e. excluding supplement users) had significantly (P < 0.05-0.001) higher serum undercarboxylated osteocalcin (by 27% and 63%, respectively) and bone-specific alkaline phosphatase (by 15% and 21%, respectively) and urinary Type I collagen cross-linked N-telopeptides concentrations (by 87% and 112%, respectively). Relative to that in their respective controls, Crohn's disease and ulcerative colitis patients had significantly (P < 0.01) lower serum total osteocalcin (by 20% and 42%, respectively) and 25-hydroxyvitamin D (by 37% and 42%, respectively), while serum parathyroid hormone levels were similar. In the combined patient group (n = 100), undercarboxylated osteocalcin was positively associated with bone markers. CONCLUSIONS: Both Crohn's disease and ulcerative colitis patients have altered bone turnover relative to that in healthy controls.

Adult↗

Immunohistochemical study of tissue factor expression in normal intestine and idiopathic inflammatory bowel disease.

AIMS: To investigate the localisation of tissue factor expression in normal and inflamed intestine. METHODS: Serial cryostat sections of tissue taken from patients with Crohn's disease (n = 8), ulcerative colitis (n = 5), and from controls (n = 5) were stained with haematoxylin and eosin and immunostained for tissue factor, collagen type IV, fibrinogen and platelet glycoprotein IIIa. RESULTS: In control tissues tissue factor was present as a continuous layer along the epithelial basal lamina: sections from controls did not immunostain for fibrinogen or platelets. In non-ulcerated inflamed mucosa, tissue factor staining intensified in cases of Crohn's disease and was associated with fibrin deposition. Staining for tissue factor was either patchy or absent in cases of ulcerative colitis and there was no fibrin deposition. This change accompanied the early destruction of the epithelial basal lamina in ulcerative colitis that was not seen in Crohn's disease. In both diseases tissue factor expression in severely inflamed and ulcerated mucosa was present on lamina propria macrophages and vascular endothelium and was associated with fibrin or platelet thrombi. In three of eight cases of Crohn's disease tissue factor expression and thrombi were evident in areas of submucosal vasculitis. These were not seen in adjacent normal vessels. CONCLUSIONS: These observations are consistent with a tissue factor haemostatic barrier in the intestine: this barrier seems to be incomplete or defective in ulcerative colitis. Tissue factor expression by macrophages and endothelial cells may be important, particularly in the microvascular thrombosis and induration which are characteristic of Crohn's disease.

Adult↗

Surface properties, connective tissue protein binding and Shiga-like toxin production of Escherichia coli isolated from patients with ulcerative colitis.

Escherichia coli strains isolated from intestinal biopsies of patients with ulcerative colitis (n 146), Crohn's disease and colonic polyposis (n 41) were analysed for binding of collagen I, collagen IV, fibronectin and laminin. Strains expressed varying degrees of binding of one or more of the four connective tissue proteins. Only 32 strains did not express binding of any of the proteins. The strains expressed low or moderate cell surface hydrophobicity. There was no correlation between protein binding and expression of cell surface hydrophobicity. E. coli isolated from inflamed rectal mucosa were slightly less negatively charged than strains isolated from healthy intestinal mucosa. Shiga-like toxins I and II were detected in 32 strains from 28 patients. Of these, 5 strains had been isolated from normal or healed tissue. In patients with inflammatory bowel disease, connective tissue proteins are exposed in intestinal ulcerations. Strains expressing binding of one or several of these proteins may have a selective advantage to colonize these lesions.

Adolescent↗

Interactions between IL-32 and tumor necrosis factor alpha contribute to the exacerbation of immune-inflammatory diseases.

IL-32 is a newly described cytokine in the human found to be an in vitro inducer of tumor necrosis factor alpha (TNFalpha). We examined the in vivo relationship between IL-32 and TNFalpha, and the pathologic role of IL-32 in the TNFalpha-related diseases - arthritis and colitis. We demonstrated by quantitative PCR assay that IL-32 mRNA was expressed in the lymphoid tissues, and in stimulated peripheral T cells, monocytes, and B cells. Activated T cells were important for IL-32 mRNA expression in monocytes and B cells. Interestingly, TNFalpha reciprocally induced IL-32 mRNA expression in T cells, monocyte-derived dendritic cells, and synovial fibroblasts. Moreover, IL-32 mRNA expression was prominent in the synovial tissues of rheumatoid arthritis patients, especially in synovial-infiltrated lymphocytes by in situ hybridization. To examine the in vivo relationship of IL-32 and TNFalpha, we prepared an overexpression model mouse of human IL-32beta (BM-hIL-32) by bone marrow transplantation. Splenocytes of BM-hIL-32 mice showed increased expression and secretion of TNFalpha, IL-1beta, and IL-6 especially in response to lipopolysaccharide stimulation. Moreover, serum TNFalpha concentration showed a clear increase in BM-hIL-32 mice. Cell-sorting analysis of splenocytes showed that the expression of TNFalpha was increased in resting F4/80+ macrophages, and the expression of TNFalpha, IL-1beta and IL-6 was increased in lipopolysaccharide-stimulated F4/80+ macrophages and CD11c+ dendritic cells. In fact, BM-hIL-32 mice showed exacerbation of collagen-antibody-induced arthritis and trinitrobenzen sulfonic acid-induced colitis. In addition, the transfer of hIL-32beta-producing CD4+ T cells significantly exacerbated collagen-induced arthritis, and a TNFalpha blockade cancelled the exacerbating effects of hIL-32beta. We therefore conclude that IL-32 is closely associated with TNFalpha, and contributes to the exacerbation of TNFalpha-related inflammatory arthritis and colitis.

Adoptive Transfer↗

The role of very late antigen-1 in immune-mediated inflammation.

The alpha1beta1 integrin, also known as "very late antigen" (VLA)-1, is normally expressed on mesenchymal cells, some epithelial cells, activated T cells, and macrophages, and interacts, via the I-domain of the extracellular domain of the alpha1 subunit, with collagen molecules in the extracellular matrix (ECM). By "outside-in" transmembranal signaling to the interior of the cell, it mediates adhesion, migration, proliferation, remodeling of the ECM, and cytokine secretion by endothelial cells, mesangial cells, fibroblasts, and immunocytes. Importantly, its expressions and functions are enhanced by inflammatory cytokines including interferon (IFN)gamma and tumor necrosis factor (TNF)alpha, thus augmenting angiogenesis and fibrosis linked, in particular, to inflammation. Moreover, within the immune system, VLA-1 marks effector memory CD4+ and CD8+ T cells that are retained in extralymphatic tissues by interactions of the integrin with collagen and produce high levels of IFNgamma. Thus, immune-mediated inflammation in vivo is inhibited by blockade of the VLA-1-collagen interaction in experimental animal models of arthritis, colitis, nephritis, and graft versus host disease (GVHD), suggesting that inhibiting the interaction of the alpha1 I-domain with its ligands or modulating "outside-in" signaling by VLA-1 would be a useful approach in the human diseases simulated by these experimental models.

Animals↗