Maresin-1 Prevents Liver Fibrosis by Targeting Nrf2 and NF-κB, Reducing Oxidative Stress and Inflammation

Liver fibrosis is a complex process characterized by the excessive accumulation of extracellular matrix (ECM) and an alteration in liver architecture, as a result of most types of chronic liver diseases such as cirrhosis, hepatocellular carcinoma (HCC) and liver failure. Maresin-1 (MaR1) is derivative of ω-3 docosahexaenoic acid (DHA), which has been shown to have pro-resolutive and anti-inflammatory effects. We tested the hypothesis that the application of MaR1 could prevent the development of fibrosis in an animal model of chronic hepatic damage. Sprague-Dawley rats were induced with liver fibrosis by injections of diethylnitrosamine (DEN) and treated with or without MaR1 for four weeks. In the MaR1-treated animals, levels of AST and ALT were normalized in comparison with DEN alone, the hepatic architecture was improved, and inflammation and necrotic areas were reduced. Cell proliferation, assessed by the mitotic activity index and the expression of Ki-67, was increased in the MaR1-treated group. MaR1 attenuated liver fibrosis and oxidative stress was induced by DEN. Plasma levels of the pro-inflammatory mediators TNF-α and IL-1β were reduced in MaR1-treated animals, whereas the levels of IL-10, an anti-inflammatory cytokine, increased. Interestingly, MaR1 inhibited the translocation of the p65 subunit of NF-κB, while increasing the activation of Nrf2, a key regulator of the antioxidant response. Finally, MaR1 treatment reduced the levels of the pro-fibrotic mediator TGF-β and its receptor, while normalizing the hepatic levels of IGF-1, a proliferative agent. Taken together, these results suggest that MaR1 improves the parameters of DEN-induced liver fibrosis, activating hepatocyte proliferation and decreasing oxidative stress and inflammation. These results open the possibility of MaR1 as a potential therapeutic agent in fibrosis and other liver pathologies.

Hypostomus sertanejo (Siluriformes: Loricariidae), new armoured catfish species from north-eastern Brazil

A re-evaluation of the armoured catfish species of Hypostomus in the Rio Jaguaribe, north-eastern Brazil, was prompted by the discovery of specimens with pale spots on a dark background collected from that basin c. 1936 and deposited at the Academy of Natural Sciences of Philadelphia. Recent field collections in the Rio Jarguaribe basin confirmed the presence of the pale-spotted specimens and its distinctiveness as a new species. Hypostomus sertanejo n. sp. is diagnosed from other species of Hypostomus by having fins and dermal-plated regions of head and body with pale spots or vermiculations on darker background, teeth slender, asymmetrically bicuspid and numerous (34-75) on dentary and premaxilla, depressed dorsal-fin spine not reaching adipose spine, unbranched pectoral-fin spine longer than unbranched pelvic-fin ray, seven branched dorsal-fin rays and one (rarely two) predorsal plate(s) bordering supraoccipital. Ancistrus salgadae Fowler 1941 is hypothesized to be a junior synonym of Hypostomus carvalhoi (Miranda-Ribeiro, 1937), a dark-spotted Hypostomus described from the Rio Granjeiro, a tributary to the upper Rio Salgado.