No abstract

In degrading the extracellular matrix, matrix metalloproteinases (MMP) and the plasminogen activator (PA) system may play a critical role in extensive remodeling that occurs in the bovine mammary gland during development, lactation, and involution. Therefore, the aim of our study was to investigate the mRNA expression of MMP-1, MMP-2, MMP-14, MMP-19, tissue inhibitor of metalloproteinases (TIMP)-1, TIMP-2, urokinase-type PA, tissue-type PA, urokinase-type PA receptor, and PA inhibitor-1 by quantitative PCR and to localize with immunohistochemistry MMP-1, MMP-2, MMP-14, and TIMP-2 proteins in the bovine mammary gland during pubertal mammogenesis, lactogenesis, galactopoiesis, and involution. Expression of mRNA for each of the studied factors was relatively lower during galactopoiesis and early involution but was markedly increased during mammogenesis and late involution, 2 stages in which tissue remodeling is especially pronounced. The localization of proteins for MMP-1, MMP-14, and TIMP-2 showed a similar trend with strong staining intensity in cytoplasm of mammary duct and alveolar epithelial cells during pubertal mammogenesis and late involution. Interestingly, MMP-2 protein was localized only in the cytoplasm of endothelial cells during late involution. Our study demonstrated clearly that expression of extracellular matrix-degrading proteinases coincides with a concomitant expression of their inhibitors. High expression levels of MMP, TIMP, and PA family members seem to be a typical feature of the nonlactating mammary gland.

Oxytocin plays a major role in lactation mainly by its action on milk ejection via the contraction of myoepithelial cells. The effect of oxytocin on milk production and the presence of oxytocin receptors on different epithelial cells suggest that this hormone may play a role in mammary epithelial cells. To determine precisely the various roles of oxytocin, we studied localization of oxytocin receptors in lactating rabbit and rat mammary tissue and the influence of oxytocin on secretory processes in lactating rabbit mammary epithelial cells. Immunolocalization of oxytocin receptors on mammary epithelial cells by immunofluorescence and in mammary tissue by immunogold in addition to in situ hybridization showed that lactating rat and rabbit mammary epithelial cells expressed oxytocin receptors. Moreover, oxytocin bound specifically to epithelial cells. To determine whether oxytocin had an effect on lactating rabbit mammary epithelial cells, isolated mammary fragments were incubated in the presence or absence of 10 −6 i.u. ml −1 of oxytocin. After 1 min of incubation with oxytocin, the morphology of epithelial cells and the localization of caseins and proteins associated with the secretory traffic suggested a striking acceleration of the transport leading to exocytosis, whereas the contraction of myoepithelial cells was only detectable after 7 min. Addition of 10 −8 g ml −1 of atosiban before the addition of oxytocin prevented the oxytocin effect on secretory processes and on myoepithelial cell contraction. Addition of 10 −6 i.u. ml −1 of vasopressin to the incubation medium did not mimic the stimulating effect of oxytocin on secretory traffic. These results show that lactating rabbit and rat mammary epithelial cells express oxytocin receptors and that oxytocin binds to these receptors. They strongly suggest that oxytocin has a dual effect on lactating mammary tissue: an acceleration of the intracellular transfer of caseins in mammary epithelial cells followed by the contraction of myoepithelial cells.

Background In HCV-infected patients with advanced liver disease, the direct antiviral agents-associated clinical benefits remain debated. We compared the clinical outcome of patients with a previous history of decompensated cirrhosis following treatment or not with direct antiviral agents from the French ANRS CO22 HEPATHER cohort. Methods We identified HCV patients who had experienced an episode of decompensated cirrhosis. Study outcomes were all-cause mortality, liver-related or non-liver-related deaths, hepatocellular carcinoma, liver transplantation. Secondary study outcomes were sustained virological response and its clinical benefits. Results 559 patients met the identification criteria, of which 483 received direct antiviral agents and 76 remained untreated after inclusion in the cohort. The median follow-up time was 39.7 (IQR: 22.7–51) months. After adjustment for multivariate analysis, exposure to direct antiviral agents was associated with a decrease in all-cause mortality (HR 0.45, 95% CI 0.24–0.84, p = 0.01) and non-liver-related death (HR 0.26, 95% CI 0.08–0.82, p = 0.02), and was not associated with liver-related death, decrease in hepatocellular carcinoma and need for liver transplantation. The sustained virological response was 88%. According to adjusted multivariable analysis, sustained virological response achievement was associated with a decrease in all-cause mortality (HR 0.29, 95% CI 0.15–0.54, p < 0.0001), liver-related mortality (HR 0.40, 95% CI 0.17–0.96, p = 0.04), non-liver-related mortality (HR 0.17, 95% CI 0.06–0.49, p = 0.001), liver transplantation (HR 0.17, 95% CI 0.05–0.54, p = 0.003), and hepatocellular carcinoma (HR 0.52, 95% CI 0.29–0.93, p = 0.03). Conclusion Treatment with direct antiviral agents is associated with reduced risk for mortality. The sustained virological response was 88%. Thus, direct antiviral agents treatment should be considered for any patient with HCV-related decompensated cirrhosis. Trial registration: ClinicalTrials.gov registry number: NCT01953458.

Our aim was to develop an explant model to define more precisely the early response of bovine mammary epithelial cells to infection. Therefore we investigated the mRNA expression encoding for some soluble immunological factors in lipopolysaccharide (LPS)-treated bovine mammary gland explants. Explants were taken out from the mammary gland of eight lactating cows after slaughter then incubated with LPS (10 mug/ml) for 6 h. The mRNA expression of alpha-lactalbumin (alpha-la), various cytokines, tumour necrosis factor (TNF)-alpha, interleukin (IL)-1beta, IL-6, IL-8, and two immunoglobulin receptors, the neonatal Fc receptor (FcRn) and polymeric immunoglobulin receptor (pIGR), were assessed with qPCR before and after 3 h and 6 h of LPS challenge. Both immunoglobulin receptors and alpha-la increased at 3 h then recovered their initial level at 6 h whereas IL-1beta, IL-6 and IL-8 increased only after 6 h (P<0.05). Surprisingly, TNF-alpha transcripts did not show any regulation in response to the LPS treatment. We nevertheless concluded that our model was valid to examine the short-term response of mammary epithelial cell challenged with LPS.