cyclic-gmp and Hepatitis

Proinflammatory activation of Kupffer cells is implicated in the effect of high-fat feeding to cause liver insulin resistance. We sought to determine whether reduced endothelial nitric oxide (NO) signaling contributes to the effect of high-fat feeding to increase hepatic inflammatory signaling and if so, whether this effect 1) involves activation of Kupffer cells and 2) is ameliorated by increased NO signaling.. Effect of NO/cGMP signaling on hepatic inflammation and on isolated Kupffer cells was examined in C57BL/6 mice, eNos(-/-) mice, and Vasp(-/-) mice fed a low-fat or high-fat diet.. We show that high-fat feeding induces proinflammatory activation of Kupffer cells in wild-type mice coincident with reduced liver endothelial nitric oxide synthase activity and NO content while, conversely, enhancement of signaling downstream of endogenous NO by phosphodiesterase-5 inhibition protects against high fat-induced inflammation in Kupffer cells. Furthermore, proinflammatory activation of Kupffer cells is evident in eNos(-/-) mice even on a low-fat diet. Targeted deletion of vasodilator-stimulated phosphoprotein (VASP), a key downstream target of endothelially derived NO, similarly predisposes to hepatic and Kupffer cell inflammation and abrogates the protective effect of NO signaling in both macrophages and hepatocytes studied in a cell culture model.. These results collectively imply a physiological role for endothelial NO to limit obesity-associated inflammation and insulin resistance in hepatocytes and support a model in which Kupffer cell activation during high-fat feeding is dependent on reduced NO signaling. Our findings also identify the NO/VASP pathway as a novel potential target for the treatment of obesity-associated liver insulin resistance.

Topics: Animals; Cell Adhesion Molecules; Cells, Cultured; Cyclic GMP; Cytokines; Dietary Fats; Endothelial Cells; Gene Expression Regulation; Hepatitis; Insulin Resistance; Kupffer Cells; Liver; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Microfilament Proteins; Molecular Targeted Therapy; Nitric Oxide; Nitric Oxide Synthase Type III; Obesity; Phosphodiesterase 5 Inhibitors; Phosphoproteins; Signal Transduction

Topics: Adult; Animals; Cyclic GMP; Hepatitis; Humans; Liver Cirrhosis; Liver Diseases; Liver Neoplasms; Liver Regeneration; Male; Rats; Rats, Inbred Strains; Receptors, Muscarinic

To investigate the possibility that a proliferative non-neoplastic process influences extracellular cyclic nucleotide concentrations, we measured plasma cyclic AMP and cyclic GMP levels in 38 patients with homozygous beta-thalassaemia. This group consisted of 20 patients with thalassaemia major transfused regularly (mean pre transfusion Hb levels, 11 g/dl), and 18 patients with thalassaemia intermedia who did not require regular blood transfusion (mean Hb levels, 8.7 g/dl). In the patient group, plasma cyclic AMP levels were similar to those of 37 normal subjects matched for age and sex, whereas plasma cyclic GMP levels were markedly higher. Moreover, in the thalassaemic patients there was a significant negative correlation between plasma cyclic GMP levels and haemoglobin concentrations, suggesting that their marked erythroid hyperplasia may play a role in determining alterations in extracellular cyclic GMP levels.

Topics: Adolescent; Adult; Cyclic AMP; Cyclic GMP; Female; Hemoglobins; Hepatitis; Homozygote; Humans; Male; Middle Aged; Reference Values; Thalassemia

To clarify the factor(s) responsible for changes in the plasma cyclic GMP concentration in liver diseases, we measured the plasma levels of cyclic GMP, along with cyclic AMP, in various clinical stages of chronic liver diseases and acute hepatitis. The level of cyclic GMP was found to increase significantly in the early stage of acute hepatitis, in the decompensated stage of liver cirrhosis, and in malignant diseases. In the former two states, it is postulated that decreased hepatic mass is responsible for the changes in the plasma cyclic GMP concentration. The retention rate of indocyanin green (ICGR15) was highly correlated with the plasma cyclic GMP level. The result suggests that the determination of plasma cyclic GMP is useful as an index of the reserve function of the liver in disease states.

Topics: Carcinoma, Hepatocellular; Cyclic AMP; Cyclic GMP; Hepatitis; Humans; Indocyanine Green; Liver Cirrhosis; Liver Diseases; Liver Neoplasms; Nucleotides, Cyclic

Urinary excretion of cyclic GMP (cGMP) and the plasma level of cyclic AMP (cAMP) were determined in patients with liver diseases. The urinary excretion of cGMP, expressed on the basis of creatinine excreted per day, was at significantly higher levels not only in primary hepatoma but also in liver cirrhosis, while the plasma level of cAMP was higher only in liver cirrhosis. Thus, the ratio of urinary cGMP excretion to plasma cAMP level in primary hepatoma was significantly higher than that in liver cirrhosis. In cirrhotic patients studied by catheterization, the level of cGMP in the hepatic vein was significantly lower than that in the superior mesenteric or portal vein, indicating the uptake of cGMP by the liver. Since cGMP excretion correlated with KICG both in liver cirrhosis and primary hepatoma, the increased cGMP excretion appeared to be explained by a reduced uptake of cGMP by the liver.

Topics: Adolescent; Adult; Aged; Carcinoma, Hepatocellular; Cyclic AMP; Cyclic GMP; Female; Hepatitis; Humans; Liver Neoplasms; Male; Middle Aged; Precancerous Conditions