MMP Mediated Degradation of Type VI Collagen Is Highly Associated with Liver Fibrosis - Identification and Validation of a Novel Biochemical Marker Assay

Background and Aims: During fibrogenesis, in which excessive remodeling of the extracellular matrix occurs, both the quantity of type VI collagen and levels of matrix metalloproteinases, including MMP-2 and MMP-9, increase significantly. Proteolytic degradation of type VI collagen into small fragments, so-called neo-epitopes, may be specific biochemical marker of liver fibrosis. The aim of this study was to develop an ELISA detecting a fragment of type VI collagen generated by MMP-2 and MMP-9, and evaluate this assay in two preclinical models of liver fibrosis. Methods: Mass spectrometric analysis of cleaved type VI collagen revealed a large number of protease-generated neo-epitopes. A fragment unique to type VI collagen generated by MMP-2 and MMP-9 was selected for ELISA development. The CO6-MMP assay was evaluated in two rat models of liver fibrosis: bile duct ligation (BDL) and carbon tetrachloride (CCl4)-treated rats. Results: Intra-and inter-assay variation was 4.1% and 10.1% respectively. CO6-MMP levels were significantly elevated in CCl4-treated rats compared to vehicle-treated rats at weeks 12 (mean 30.9 ng/mL vs. 12.8 ng/mL, p = 0.002); week 16 (mean 34.0 ng/mL vs. 13.7 ng/mL, p = 0.0018); and week 20 (mean 35.3 ng/mL vs. 13.3 ng/mL, p = 0.0033) with a tight correlation between hepatic collagen content and serum levels of CO6-MMP (R-2 = 0.58,

The effect of ileal interposition surgery on enteroendocrine cell numbers in the UC Davis type 2 diabetes mellitus rat

AimTo investigate the short-term effect of ileal interposition (IT) surgery on gut morphology and enteroendocrine cell numbers in the pre-diabetic UC Davis type 2 diabetes mellitus (UCD-T2DM) rat.Study designTwo-month old male UCD-T2DM rats underwent either sham (n=5) or IT (n=5) surgery. Intestines were collected 1.5months after surgery. The jejunum, ileum and colon regions were processed for histochemical and immunohistochemical labeling and stereological analyses of changes in gut morphometry and number of enteroendocrine cells.ResultsStereological analysis showed that intestinal volume, luminal surface area and the number of all chromogranin A-positive enteroendocrine cells were markedly increased in the IT rats compared with sham-operated animals. Subanalyses of the glucagon-like peptide 2, cholecystokinin, serotonin cells and the neurotensin immunoreactive sub-pool of enteroendocrine cells in the IT region revealed an increase in numbers across phenotypes. However, the density of the different cell types varied.ConclusionIT surgery in the UCD-T2DM rat leads to rapid alterations in gut morphometry and an increase in the number of enteroendocrine cells. This effect may potentially explain why IT surgery delays the onset of type 2 diabetes in the UCD-T2DM rat

The effect of ileal interposition surgery on enteroendocrine cell numbers in the UC Davis type 2 diabetes mellitus rat.

AimTo investigate the short-term effect of ileal interposition (IT) surgery on gut morphology and enteroendocrine cell numbers in the pre-diabetic UC Davis type 2 diabetes mellitus (UCD-T2DM) rat.Study designTwo-month old male UCD-T2DM rats underwent either sham (n=5) or IT (n=5) surgery. Intestines were collected 1.5months after surgery. The jejunum, ileum and colon regions were processed for histochemical and immunohistochemical labeling and stereological analyses of changes in gut morphometry and number of enteroendocrine cells.ResultsStereological analysis showed that intestinal volume, luminal surface area and the number of all chromogranin A-positive enteroendocrine cells were markedly increased in the IT rats compared with sham-operated animals. Subanalyses of the glucagon-like peptide 2, cholecystokinin, serotonin cells and the neurotensin immunoreactive sub-pool of enteroendocrine cells in the IT region revealed an increase in numbers across phenotypes. However, the density of the different cell types varied.ConclusionIT surgery in the UCD-T2DM rat leads to rapid alterations in gut morphometry and an increase in the number of enteroendocrine cells. This effect may potentially explain why IT surgery delays the onset of type 2 diabetes in the UCD-T2DM rat