Lipoxin A4 exerts protective effects against experimental acute liver failure by inhibiting the NF-κB pathway.

Although rare, acute liver failure (ALF) is associated with high levels of mortality, warranting the development of novel therapies. Nuclear factor-κB (NF-κB), tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6) play roles in ALF. Lipoxin A4 (LXA4) has been shown to alleviate inflammation in non-hepatic tissues. In the present study, we explored whether LXA4 exerted hepatoprotective effects in a rat model of ALF. A rat model of ALF was generated by intraperitoneal injections of D-galactosamine (300 mg/kg) and lipopolysaccharide (50 µg/kg). Animals were randomly assigned to: control group (no ALF); model group (ALF); and the groups treated with a low dose (0.5 µg/kg), medium dose (1 µg/kg), and high dose (2 µg/kg) of LXA4 (all with ALF); and pyrrolidine dithiocarbamate (PDTC)-treated group (ALF and 100 mg/kg PDTC, an inhibitor of NF-κB). Liver histology was measured using H&E staining, serum levels by ELISA, and liver mRNA expression was measured by RT-PCR for the detection of the pro­inflammatory cytokines TNF-α and IL-6. Liver cell apoptosis (as measured using the TUNEL method and examining caspase-3 activity), and Kupffer cell NF-κB activity [using an electrophoretic mobility shift assay (EMSA)] were examined. Serum levels of transaminases, TNF-α and interleukin-6 (IL-6) were substantially higher in the model group compared to controls. In the model group, significant increases in TNF-α and IL-6 mRNA expression, TUNEL­positive cells, and caspase-3 activity in the liver tissue were noted. LXA4 improved liver pathology and significantly decreased the indicators of inflammatory response and apoptosis in a dose-dependent manner. High-dose LXA4 provided better protection than PDTC. LXA4 administration significantly decreased NF-κB expression in hepatocytes and Kupffer cells. These results indicated that LXA4 inhibited NF-κB activation, reduced the secretion of pro-inflammatory cytokines, and inhibited apoptosis of liver cells, thereby exerting protective effects against ALF.

The effects of Tao-Hong-Si-Wu on hepatic necroinflammatory activity and fibrosis in a murine model of chronic liver disease.

BACKGROUND: Tao-Hong-Si-Wu decoction (THSWD) is a traditional Chinese herbal medicine that has been used for centuries in the treatment of Chinese patients with chronic liver disease. Recently, THSWD has been reported to alter vascular endothelial growth factor (VEGF) induced angiogenesis, raising the possibility that in addition to its anti-inflammatory properties; THSWD might also inhibit hepatic blood flow associated fibrosis. AIM: To document the effects of THSWD on hepatic necroinflammatory disease activity, fibrosis and VEGF signaling in a murine model of chronic liver disease. METHODS: Sixty adult mice were equally divided into six study groups. Five groups were exposed to subcutaneous carbon tetrachloride (0.1 ml/10 g BW) for six weeks. Three of the five groups were treated with different concentrations of THSWD (4.25, 8.50, 17.00 g/kg), one with 0.1mg/kg of Colchicine (positive control), and one with physiologic saline (negative control). Mice in the sixth group were not exposed to CCl4 and remained untreated (healthy controls). Liver enzymes/function tests, hyaluronic acid and laminin levels were measured in serum, and hepatic histology, VEGF, Flt-1 and kinase insert domain-containing receptor (KDR), Akt and phosphorylated Akt (pAkt) expression were documented in liver tissue at the end of treatment. RESULTS: Hepatic necroinflammatory disease activity and fibrosis were significantly attenuated in THSWD treated mice in a dose dependent manner. These beneficial results were similar and often exceeded those achieved with Colchicine. In addition, VEGF, Flt-1, KDR, Akt and pAkt mRNA and protein expression were reduced in TSHWD treated mice. CONCLUSIONS: In this animal model of chronic liver disease, THSWD decreased hepatic necroinflammatory disease and fibrosis. Inhibition of VEGF expression and downstream signaling were associated with these findings. Further studies with this and other TCMs as treatment for chronic liver disease are warranted.

Analysis of phosphatidylinositol 3-kinase activation in the adipose tissue of gestational diabetes mellitus patients and insulin resistance.

The P85 regulatory subunit protein and gene expression and P110 catalylic subunit activity of phosphatidylinositol 3-kinase (PI-3K) were investigated in adipose tissue of patients with gestational diabetes mellitus (GDM) in order to explore the molecular mechanisms of insulin resistance (IR) of GDM. Samples from patients with GDM (n=50), and controls (n=50) were collected. Fasting insulin (FIN) was determined by radioimmunoassay. Fasting plasma glucose (FPG) was measured by oxidase assay. Western blot technique was used to detect the levels of PI-3K P85 subunit in adipose tissues of patients with GDM. The mRNA expression of PI-3K P85 subunit was detected by reverse transcription polymerase chain reaction (RT-PCR) method in the adipose tissue. PI-3K activity was examined by immunoprecipitation, thin-layer chromatography and gamma scintillation counting. The results were analyzed statistically. It was found that the levels of FPG, FIN and HOMA-IR in GDM group were significantly higher than those in control group (all P<0.01). There was no significant difference in the protein and gene expression of PI-3K P85 subunit between GDM group and control group (P>0.05). PI-3K activity was significantly decreased to 82.89% in GDM group as compared with control group (P<0.01) and negatively correlated with HOMA-IR (r=-0.75, P<0.01). It was concluded that PI-3K in GDM patients may be involved in the insulin signaling pathway, resulting in IR of GDM.

The expression of resistin in adipose tissues of patients with polycystic ovary syndrome and insulin resistance.

The relationship between the expression of resistin in polycystic ovary syndrome (PCOS) and insulin resistance was investigated. The plasma resistin concentrations in 35 patients with PCOS and 40 controls were measured by ELISA. Luteinizing hormone (LH), follicle-stimulating hormone (FSH), and fasting insulin (FIN) were tested by radioimmunoassay. Insulin resistance index (HOMA-IR) was calculated. Fasting plasma glucose (FPG) was determined by oxidase test. Western blot and reverse transcriptase PCR (RT-PCR) methods were used to detect the expression of resistin in adipose tissues. The levels of plasma resistin, LH, LH/FSH and FIN and HOMA-IR in patients with PCOS were significantly higher than those in control group (all P<0.05). Plasma resistin was correlated positively with FPG, FIN, HOMA-IR, LH and LH/FSH (r=0.56, 0.60, 0.65, 0.48, and 0.42 respectively). Resistin protein and mRNA expression levels in patients with PCOS were significantly higher than those in normal tissues (all P<0.01). It was concluded that resistin might be involved in the pathogenesis of insulin resistance of PCOS.