Ammonia produces pathological changes in human hepatic stellate cells and is a target for therapy of portal hypertension

BACKGROUND AND AIMS: Hepatic stellate cells (HSCs) are vital to hepatocellular function and the liver response to injury. They share a phenotypic homology with astrocytes that are central in the pathogenesis of hepatic encephalopathy, a condition in which hyperammonemia plays a pathogenic role. This study tested the hypothesis that ammonia modulates human HSC activation in vitro and in vivo, and evaluated whether ammonia lowering, by using l-ornithine phenylacetate (OP), modifies HSC activation in vivo and reduces portal pressure in a bile duct ligation (BDL) model. METHODS: Primary human HSCs were isolated and cultured. Proliferation (BrdU), metabolic activity (MTS), morphology (transmission electron, light and immunofluorescence microscopy), HSC activation markers, ability to contract, changes in oxidative status (ROS) and endoplasmic reticulum (ER) were evaluated to identify effects of ammonia challenge (50 μM, 100 μM, 300 μM) over 24–72 h. Changes in plasma ammonia levels, markers of HSC activation, portal pressure and hepatic eNOS activity were quantified in hyperammonemic BDL animals, and after OP treatment. RESULTS: Pathophysiological ammonia concentrations caused significant and reversible changes in cell proliferation, metabolic activity and activation markers of hHSC in vitro. Ammonia also induced significant alterations in cellular morphology, characterised by cytoplasmic vacuolisation, ER enlargement, ROS production, hHSC contraction and changes in pro-inflammatory gene expression together with HSC-related activation markers such as α-SMA, myosin IIa, IIb, and PDGF-Rβ. Treatment with OP significantly reduced plasma ammonia (BDL 199.1 μmol/L ± 43.65 vs. BDL + OP 149.27 μmol/L ± 51.1, p <0.05) and portal pressure (BDL 14 ± 0.6 vs. BDL + OP 11 ± 0.3 mmHg, p <0.01), which was associated with increased eNOS activity and abrogation of HSC activation markers. CONCLUSIONS: The results show for the first time that ammonia produces deleterious morphological and functional effects on HSCs in vitro. Targeting ammonia with the ammonia lowering drug OP reduces portal pressure and deactivates hHSC in vivo, highlighting the opportunity for evaluating ammonia lowering as a potential therapy in cirrhotic patients with portal hypertension

Transcriptome analysis of Paspalum notatum and Paspalum vaginatum under water deficit condition.

Drought is one of the abiotic stresses that most affect plant growth and productivity. Grasses of the genus Paspalum are successfully used as turf and forage in Australia, Argentina, Brazil and United States. Paspalum notatum has good forage quality, and P. vaginatum, high tolerance to salinity. In addition, their potential to tolerate drought has been described previously, making them interesting for transcriptome studies under water deficit. The objective of this work was to analyze the gene expression profiles of both species in response to drought.Genética 2019

Confirmação da identidade genética das plantas produtoras de sementes da cultivar BRS Guatã de Feijão Guandu com marcadores moleculares.

O feijão guandu (Cajanus Cajan) é uma espécie de potencial forrageiro, com boa adaptabilidade e fixadora de nitrogênio