Fatty Acids Lipidome and Oxidative Stress in Liver Transplantation

• Post operative graft function after liver transplantation [ Time Frame: Change in graft function after 7 and 30 days after liver transplantation ] [ Designated as safety issue: No ]
  • Multiple lipid metabolism biomarkers (fatty acids, cholesterol and oxysterols) are evaluated in the plasma of liver cirrhosis patients before liver transplantation. A logistic regression model is used to evaluate which of these biomarkers is an independent predictor of graft function
  
  

• Early gene expression in the liver graft [ Time Frame: 30 days ] [ Designated as safety issue: No ]
  Assessment of lipid metabolism-, oxidative stress-, and ER stress-gene expression in graft tissue liver tissue specimens of patients undergoing organ transplantation and their impact on graft function. Lipid metabolism and ER gene expression (genes: LDL-R, HMGCR, CD81, SREBP2, NPC1L1, XBP-1, XBP2, ATF6, GRP78, GRP94, LXR, INSIG1, INSIG2) in liver graft specimens at transplantation before and after ischemia-reperfusion injury; downregulated and upregulated genes are related to early graft function.
  
  

Liver has a central role in fatty acids metabolism that is impaired in chronic liver diseases. Polyunsaturated fatty acids are reportedly reduced in liver cirrhosis, which is considered a condition of essential fatty acids deficiency. However, there is a paucity of data concerning the level of the multitude of circulating fatty acids in liver cirrhosis. Oxidative stress is involved in the pathogenesis of chronic liver disease and fibrosis. Increased oxidative stress with impaired antioxidant status at the systemic level has been described in different chronic liver diseases and negatively influences graft function after liver transplantation (Poli G. 2000, Loguercio C 2003). 7-Ketocholesterol and 7beta-hydroxycholesterol, prototype molecules of free radical-mediated cholesterol oxidation, are very important oxysterols currently accepted as in vivo reliable markers of oxidative stress. High oxysterols plasma levels are associated with an alteration of normal plasma fatty acid pattern in cystic fibrosis (Iuliano 2009). The Model for End-Stage Liver Disease (MELD) score is a common score used routinely to stage liver function in patients with liver cirrhosis (Al Sibae 2010). After ischemia-reperfusion injury at liver transplantation oxidative stress, hepatic endoplasmic reticulum (ER) stress and cholesterol metabolism are interrelated key processes to preserve graft regeneration and function. A blood sample is obtained in each subject to measure MELD score at the first visit and at liver transplantation. Further blood samples are collected at days seven and 30 post transplantation. Blood samples are also obtained from healthy subjects. Liver biopsy samples are obtained from liver transplant donors. Oxidative stress and fatty acids lipidomics are measured to evaluate the actual plasma concentration in liver cirrhosis patients to be compared with healthy controls. Oxidative stress and fatty acids are also analyzed as a function of disease status, and for its influence on transplant outcomes. Lipid metabolism gene and endoplasmic stress reticulum gene expression are evaluated in liver biopsy specimen to study the influence on graft function.