flavin-adenine-dinucleotide and Non-alcoholic-Fatty-Liver-Disease

Augmenter of liver regeneration (ALR), a ubiquitous fundamental life protein, is expressed more abundantly in the liver than other organs. Expression of ALR is highest in hepatocytes, which also constitutively secrete it. ALR gene transcription is regulated by NRF2, FOXA2, SP1, HNF4α, EGR-1 and AP1/AP4. ALR's FAD-linked sulfhydryl oxidase activity is essential for protein folding in the mitochondrial intermembrane space. ALR's functions also include cytochrome c reductase and protein Fe/S maturation activities. ALR depletion from hepatocytes leads to increased oxidative stress, impaired ATP synthesis and apoptosis/necrosis. Loss of ALR's functions due to homozygous mutation causes severe mitochondrial defects and congenital progressive multiorgan failure, suggesting that individuals with one functional ALR allele might be susceptible to disorders involving compromised mitochondrial function. Genetic ablation of ALR from hepatocytes induces structural and functional mitochondrial abnormalities, dysregulation of lipid homeostasis and development of steatohepatitis. High-fat diet-fed ALR-deficient mice develop non-alcoholic steatohepatitis (NASH) and fibrosis, while hepatic and serum levels of ALR are lower than normal in human NASH and NASH-cirrhosis. Thus, ALR deficiency may be a critical predisposing factor in the pathogenesis and progression of NASH.

Topics: Adenosine Triphosphate; Animals; Cytochromes c; Flavin-Adenine Dinucleotide; Humans; Lipids; Liver; Liver Regeneration; Mice; Mitochondria; NF-E2-Related Factor 2; Non-alcoholic Fatty Liver Disease; Oxidoreductases Acting on Sulfur Group Donors

Human placental extract (HPE) is a traditional medicine that has been used for the symptomatic treatment of liver disease without any verifying clinical evidence. This study aimed to evaluate the efficacy and safety of HPE in patients with alcoholic or nonalcoholic steatohepatitis (ASH or NASH). We designed this clinical trial as a multicenter, open-label, randomized, comparative noninferiority study to improve the reliability of analyses. The enrollment criteria were limited to ASH or NASH patients with serum alanine aminotransferase (ALT) 1.5-fold higher than the normal level. Patients in the control group were treated with a commercially available mixture of liver extract and flavin adenine dinucleotide (LE–FAD). Intention-to-treat (ITT) analysis was applied to 194 patients, and per-protocol (PP) analysis was available for 154 patients. The rate of primary goal achievement of treatment efficacy was arbitrarily defined as 20% or greater improvement in ALT level compared with the pretreatment level and did not differ significantly between the HPE and control groups [62.9% (44/70) vs. 48.8% (41/84); p=0.0772]. ITT and modified ITT analysis showed results similar to those of PP analysis. Adverse drug reactions (ADRs) of minimal to moderate degree occurred in 3.1% of patients. The ADR and treatment compliance rates were similar in both groups. In conclusion, the clinical value of HPE in the treatment of ASH and NASH is equivalent to that of LE–FAD.

Topics: Adult; Fatty Liver, Alcoholic; Female; Flavin-Adenine Dinucleotide; Humans; Liver Extracts; Male; Middle Aged; Non-alcoholic Fatty Liver Disease; Placental Extracts

Flavin adenine dinucleotide (FAD) interacts with flavoproteins to mediate oxidation-reduction reactions required for cellular energy demands. Not surprisingly, mutations that alter FAD binding to flavoproteins cause rare inborn errors of metabolism (IEMs) that disrupt liver function and render fasting intolerance, hepatic steatosis, and lipodystrophy. In our study, depleting FAD pools in mice with a vitamin B2-deficient diet (B2D) caused phenotypes associated with organic acidemias and other IEMs, including reduced body weight, hypoglycemia, and fatty liver disease. Integrated discovery approaches revealed B2D tempered fasting activation of target genes for the nuclear receptor PPARα, including those required for gluconeogenesis. We also found PPARα knockdown in the liver recapitulated B2D effects on glucose excursion and fatty liver disease in mice. Finally, treatment with the PPARα agonist fenofibrate activated the integrated stress response and refilled amino acid substrates to rescue fasting glucose availability and overcome B2D phenotypes. These findings identify metabolic responses to FAD availability and nominate strategies for the management of organic acidemias and other rare IEMs.

Topics: Animals; Fasting; Fatty Acids; Flavin-Adenine Dinucleotide; Flavoproteins; Glucose; Liver; Mice; Non-alcoholic Fatty Liver Disease; Oxidation-Reduction; PPAR alpha