Knockout of microRNA-21 reduces biliary hyperplasia and liver fibrosis in cholestatic bile duct ligated mice.

Cholestasis is a condition that leads to chronic hepatobiliary inflammation, fibrosis, and eventually cirrhosis. Many microRNAs (miRs) are known to have a role in fibrosis progression; however, the role of miR-21 during cholestasis remains unknown. Therefore, the aim of this study was to elucidate the role of miR-21 during cholestasis-induced biliary hyperplasia and hepatic fibrosis.

Inhibition of mast cell-derived histamine secretion by cromolyn sodium treatment decreases biliary hyperplasia in cholestatic rodents.

Cholangiopathies are characterized by dysregulation of the balance between biliary growth and loss. We have shown that histamine (HA) stimulates biliary growth via autocrine mechanisms. To evaluate the paracrine effects of mast cell (MC) stabilization on biliary proliferation, sham or BDL rats were treated by IP-implanted osmotic pumps filled with saline or cromolyn sodium (24 mg/kg BW/day (inhibits MC histamine release)) for 1 week.

Tetrahydrobiopterin attenuates superoxide-induced reduction in nitric oxide.

NADPH oxidase, a source of superoxide anion (·O2(-)), can be stimulated by oxidized low-density lipoprotein (OxLDL). We examined whether tetrahydrobiopterin (BH4) could reduce OxLDL-induced ·O2(-) production by NADPH oxidase, increasing nitric oxide (NO) synthesis. Endothelial cells incubated with OxLDL produced more ·O2(-) (35-67%) than untreated cells, with the highest increase 1 hour after OxLDL addition.