Postprandial Lipotoxicity and Nonalcoholic Fatty Liver Disease
Condition: Nonalcoholic Fatty Liver Disease (NAFLD)
MeSH terms: Liver Diseases; Fatty Liver; Non-alcoholic Fatty Liver Disease
Study type: Interventional

Summary: 
      Nonalcoholic fatty liver disease (NAFLD) is mainly considered a nutrition-related disease and
      life-style/diet interventions showed some promising results. But in spite of this, there are
      no available markers to efficiently guide interventions. the hypothesize put farth by the
      investigators is that NAFLD patients develop postprandial abnormalities of plasma lipids upon
      "western diet" challenge, more severe in steatohepatitis (NASH) than in pure steatosis
      (NAFL), promoting liver injury. Our study aims to evaluate the presence of toxic lipids (such
      as free-fatty acids, ceramides, diacylglycerols, sphingolipids) in postprandial state after
      ingestion of a "western diet" in NAFLD patients. Consecutive patients (group 1: NAFL
      patients; group 2: NASH patients) with biopsy-proven NAFLD (liver biopsy < 6 months) will be
      recruited during a period of 12 month. Blood samples will be drawn at fasting, 2hours,
      4hours, 6hours and 8hours after ingestion of a "western diet" meal. Plasma lipid profiles
      using lipidomics, circulating markers of liver injury and inflammation will be analyzed. the
      investigators will also assess the hepatotoxicity of plasma from NAFL or NASH patients
      in-vitro.
    

Detailed description: 
      Factors driving progression from steatosis (NAFL) to steatohepatitis (NASH) in patients with
      non-alcoholic fatty liver disease (NAFLD) remain largely unknown. Considerable data now
      indicate that steatosis per se is not a hepatotoxic event and may represent in fact a
      protective mechanism against free fatty acid (FFA)-induced toxicity. the investigators
      previously showed that Kupffer cells from NASH mice accumulate more toxic lipids (ceramides,
      diacylglycerols, sphingolipids) enhancing their proinflammatory polarization. Therefore,
      "quality" of accumulating lipids rather than "quantity" may play a central role in NAFLD
      progression. This is a pilot comparative study aiming to evaluate the presence of toxic
      lipids (such as free-fatty acids, ceramides, diacylglycerols, sphingolipids) in postprandial
      state after ingestion of a "western diet" in NAFL and NASH patients. The secondary outcomes
      were: to evaluate the relationship between postprandial circulating lipids and markers of
      liver injury and proinflammatory cytokines; to evaluate hepatotoxicity of postprandial lipids
      in vitro. A total of 24 consecutive patients (group 1: 12 NAFL patients; group 2: 12 NASH
      patients) with biopsy-proven NAFLD (liver biopsy < 6 months) will be recruited. A dietary
      evaluation covering the 2 previous weeks will be performed. Detailed anthropometric data will
      be collected (body mass index, waist and hip circumferences, abdominal height, cutaneous
      skinfolds) and serum metabolic parameters (standard lipid profile, lipoprotein levels,
      fasting plasma glucose, insulin levels, C-peptide levels, hemoglobin A1c) will be evaluated.
      After a 12hours overnight fast, patients will undergo an oral "western diet" test consisting
      in the ingestion of a high saturated fat, high refined sugar, high fructose-meal called
      "western diet" (800 kcal/meal). Blood samples will be drawn at fasting and then 2, 4, 6 and
      8hours after ingestion of the standard meal. Each time plasma and serum samples will be
      stored at -80°C for subsequent analysis. Lipidomics will be used to quantify each plasma
      lipid class (neutral lipids, phospholipids and fatty acid methyl esters). Serum levels of
      cytokines will be assessed using multiple assay technology. Markers of liver injury will be
      assessed (aminotransferases, Keratin 18 fragments, microRNA-122) in the serum. Hepatocytes
      will be cultured with plasma from NAFL or NASH patients, and incubated overnight. In vitro
      hepatotoxicity will be evaluated using TUNEL assay, MTT assay and LDH release assay. the
      investigators anticipate that inflammation together with hepatocyte death will occur in NAFLD
      patients who develop specific postprandial plasma lipid changes with an increase in toxic
      lipid levels. Such patients may develop more severe liver lesions (inflammation,
      fibrosis/cirrhosis) and benefit of interventions. Identification of a toxic plasma lipid
      profile may help choosing the adequate diet in order to prevent deleterious lipid formation.
      Identification of a toxic postprandial plasma lipid signature specific to hepatotoxicity may
      also serve to develop a discrimination index to be further validated in clinical practice.
    

Intervention name(s): western diet" meal
Intervention type(s): Other
Intervention description(s): A "western diet" meal (high saturated fat, high refined sugar, high fructose) will be administered in each group (800 kcal/meal) after an overnight fast.
Allocation: Non-Randomized
Intervention model: Parallel Assignment
Intervention model description: A "western diet" meal (high saturated fat, high refined sugar, high fructose) will be administered in each group (800 kcal/meal) after an overnight fast.
Masking: None (Open Label)
Primary purpose: Other
Keywords: NAFLD, toxic lipids, postprandial lipotoxicity