Hepatic lipid metabolism changes in short-and long-term prehepatic portal hypertensive rats

AIM: To verify the impairment of the hepatic lipid metabolism in prehepatic portal hypertension. METHODS: The concentrations of free fatty acids, diacylglycerol, triglycerides, and phospholipids were assayed by using D-[U-14C] glucose incorporation in the different lipid fractions and thin-layer chromatography and cholesterol was measured by spectrophotometry, in liver samples of Wistar rats with partial portal vein ligation at short- (1 mo) and long-term (1 year) (i.e. portal hypertensive rats) and the control rats. RESULTS: In the portal hypertensive rats, liver phospholipid synthesis significantly decreased (7.42 ± 0.50 vs 4.70 ± 0.44 nCi/g protein; P < 0.01) and was associated with an increased synthesis of free fatty acids (2.08 ± 0.14 vs 3.36 ± 0.33 nCi/g protein; P < 0.05), diacylglycerol (1.93 ± 0.2 vs 2.26 ± 0.28 nCi/g protein), triglycerides (2.40 ± 0.30 vs 4.49 ± 0.15 nCi/g protein) and cholesterol (24.28 ± 2.12 vs 57.66 ± 3.26 mg/g protein; P < 0.01). CONCLUSION: Prehepatic portal hypertension in rats impairs the liver lipid metabolism. This impairment consists in an increase in lipid deposits (triglycerides,diacylglycerol and cholesterol) in the liver, accompanied by a decrease in phospholipid synthesis.

Splanchnic-aortic inflammatory axis in experimental portal hypertension

Splanchnic and systemic low-grade inflammation has been proposed to be a consequence of long-term prehepatic portal hypertension.This experimental model causes minimal alternations in the liver,thus making a more selective study possible for the pathological changes characteristic of prehepatic portal hypertension.Low-grade splanchnic inflammation after longterm triple partial portal vein ligation could be associated with liver steatosis and portal hypertensive intestinal vasculopathy.In fact,we have previously shown that prehepatic portal hypertension in the rat induces liver steatosis and changes in lipid and carbohydrate metabolism similar to those produced in chronic inflammatory conditions described in metabolic syndrome in humans.Dysbiosis and bacterial translocation in this experimental model suggest the existence of a portal hypertensive intestinal microbiome implicated in both the splanchnic and systemic alterations related to prehepatic portal hypertension.Among the systemic impairments,aortopathy characterized by oxidative stress,increased levels of proinflammatory cytokines and profibrogenic mediators stand out.In this experimental model of long-term triple portal vein ligated-rats,the abdominal aortic proinflammatory response could be attributed to oxidative stress.Thus,the increased aortic reduced-nicotinamide-adenine dinucleotide phosphate[NAD(P)H]oxidase activity could be associated with reactive oxygen species production and promote aortic inflammation.Also,oxidative stress mediated by NAD(P)H oxidase has been associated with risk factors for inflammation and atherosclerosis.The splanchnic and systemic pathology that is produced in the long term after triple partial portal vein ligation in the rat reinforces the validity of this experimental model to study the chronic low-grade inflammatory response induced by prehepatic portal hypertension.