Altered colonic mucosal availability of n-3 and n-6 polyunsaturated fatty acids in ulcerative colitis and the relationship to disease activity.

BACKGROUND AND AIMS: The polyunsaturated fatty acids (PUFA) arachidonic acid (AA, n-6) and eicosapentaenoic acid (EPA, n-3) are precursors of eicosanoids and other lipid mediators which have critical roles in inflammation. The mediators formed from the different PUFA have different potencies. We hypothesised that metabolic changes associated with colonic mucosal inflammation would modify the bioavailability of the eicosanoid precursors AA and EPA. METHODS: Colonic mucosa biopsies were obtained from patients with ulcerative colitis and from matched controls. Inflammation was graded endoscopically and histologically. Esterified and non-esterified fatty acids were determined within the biopsies using gas chromatography-mass spectrometry and liquid chromatography-mass spectrometry, respectively. RESULTS: Biopsy samples were collected from 69 UC patients (54 providing both inflamed and non-inflamed mucosa) and 69 controls. Inflamed mucosa had higher AA (p<0.001) and lower EPA (p<0.010) contents and a higher AA:EPA ratio (p<0.001). Inflamed mucosa also had higher docosapentaenoic acid (DPA) and docosahexaenoic acid (DHA) and lower linoleic acid (LA) and α-linolenic acid (α-LNA) contents (all p<0.001), compared to non-inflamed and controls. There were significant correlations between severity of inflammation and contents of AA, DPA and DHA (positive correlations) and of LA, α-LNA and EPA (negative correlations). CONCLUSIONS: Higher AA, AA:EPA ratio, DPA and DHA and lower LA, α-LNA and EPA are seen in inflamed mucosa in UC and correlate with severity of inflammation. This suggests an alteration in fatty acid metabolism in the inflamed gut mucosa, which may offer novel targets for intervention and should be considered if nutritional strategies are used.

Cytokine mucosal expression in ulcerative colitis, the relationship between cytokine release and disease activity.

BACKGROUND: Ulcerative colitis (UC) is an inflammatory bowel disease with conflicting evidence from studies on the roles of TNFα, IL-8, TGFß and other cytokines and characterised by neutrophil infiltration and tissue destruction. AIM: To compare cytokine profiles of inflamed and non-inflamed mucosa in patients with distal UC, and matched controls. METHODS: Patients were prospectively recruited, mucosal biopsies at flexible sigmoidoscopy (FS) were taken from UC patients within macroscopically inflamed and non-inflamed proximal mucosa, and from age-sex matched controls undergoing FS. Endoscopic and histological inflammation was graded. Quantitative cytokine analysis for IL-4, TNFα, IL-17A, IL-8, IL-10, TGFß and IFNγ was carried out on tissue homogenates. Statistical comparison was by Wilcoxon signed rank pair analysis, Mann-Whitney U test and Spearman's correlation. RESULTS: 69 active UC patients (54 paired non-inflamed/inflamed mucosa) and 69 controls were compared. In inflamed mucosa, elevation in IL-8 and reduction in TGFß was measured compared with non-inflamed mucosa (p<0.001; p<0.02) and control mucosa (p<0.001; p<0.001); IL-8 was positively correlated (rs=0.481, p<0.01) and TGFß inversely correlated (rs=0.462; p<0.01) with grade of inflammation. TNFα concentration was not significantly different. Comparisons of inflamed with non-inflamed mucosa also demonstrate significant reduction in concentration of IFNγ (p<0.001), IL-4 (p<0.005) and IL-17A (p<0.002). CONCLUSION: Our findings suggest that IL-8 is elevated and TGFß is reduced in distal colitis. Lower concentration of IFNγ, IL-4 and IL-17A were also noted. TNFα levels were unchanged. These findings suggest that the inflammatory response in UC may predominantly involve IL-8 mediated neutrophil infiltration and failure of TGFß mediated tissue healing.

Clinical and functional significance of α9ß1 integrin expression in breast cancer: a novel cell-surface marker of the basal phenotype that promotes tumour cell invasion.

Integrin α9ß1 is a receptor for ECM proteins, including Tenascin-C and the EDA domain of fibronectin, and has been shown to transduce TGFß signalling. This study has examined the expression pattern of α9ß1 in 141 frozen breast carcinoma samples and related expression to prognostic indices, molecular subtype and patient outcome. Effects of α9ß1 on tumour cell migration and invasion were assessed using blocking antibody and gene transduction approaches. Integrin α9ß1 localized to myoepithelial cells in normal ducts and acini, a pattern maintained in DCIS. A subset (17%) of invasive carcinomas exhibited tumour cell expression of α9ß1, which related significantly to the basal-like phenotype, as defined by either CK5/6 or CK14 expression. Tumour expression of α9ß1 showed a significant association with reduced overall patient survival (p < 0.0001; HR 5.94, 95%CI 3.26-10.82) and with reduced distant-metastasis-free survival (p < 0.0001; HR 6.37, CI 3.51-11.58). A series of breast cancer cell lines was screened for α9ß1 with the highly invasive basal-like GI-101 cell line expressing significant levels. Both migration and invasion of this line were reduced significantly in the presence of α9-blocking antibody and following α9-knockdown with siRNA. Conversely, migratory and invasive behaviour of α9-negative MCF7 cells and α9-low MDA MB468 cells was enhanced significantly by over-expression of α9. Thus, α9ß1 acts as a novel marker of the basal-like breast cancer subtype and expression is associated with reduced survival, while its ability to promote breast cancer cell migration and invasion suggests that it contributes to the aggressive clinical behaviour of this tumour subtype.