In rodents, consuming fructose is linked to higher levels of proteins associated with liver scarring and lower levels of Sirt1 protein, which also undergoes specific chemical modifications that may...
Mechanism
Synthesis from 1 study
Too much fructose breaks down the gut's protective lining, letting toxins into the blood. These toxins reach the liver and turn on scar-making cells, while also disabling a key protein that keeps liver cells healthy. Without that protein, fat builds up and scars form, leading to liver damage over...
Most probable mechanism
Eating too much fructose damages the gut lining by breaking down the proteins that hold intestinal cells together, letting bacterial toxins leak into the bloodstream. These toxins reach the liver and trigger scar-forming cells to activate and produce excess collagen, while also disabling a protective protein that normally keeps liver cells healthy and prevents fat buildup. Without this protective protein, the liver accumulates fat and scars over time.
Fructose consumption increases the activity of the enzyme CYP2E1 in the intestine, leading to the production of reactive nitrogen species.
Reactive nitrogen species cause tyrosine nitration of intestinal junctional proteins, which are then tagged with ubiquitin and degraded by the proteasome.
Loss of intestinal junctional proteins disrupts the epithelial barrier, increasing permeability and allowing bacterial endotoxin to enter the bloodstream.
Circulating endotoxin binds to TLR4 receptors on hepatic stellate cells, triggering their transformation into collagen-producing myofibroblasts.
Activated myofibroblasts produce and deposit extracellular matrix proteins, including collagen-1, collagen-4, and fibrogenic mediators such as TGF-β and α-SMA.
Fructose-induced nitrative stress in the liver causes tyrosine nitration of Sirt1 protein, which is subsequently ubiquitinated and degraded by the proteasome.
Loss of Sirt1 reduces deacetylation of histones and transcriptional regulators, leading to decreased mitochondrial function and fatty acid oxidation, while promoting lipid synthesis.
Mitochondrial dysfunction and lipid accumulation in hepatocytes create a pro-fibrotic environment that enhances stellate cell activation and sustains fibrosis progression.
Evidence from Studies
Supporting (1)
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Fructose Promotes Leaky Gut, Endotoxemia and Liver Fibrosis through CYP2E1-Mediated Oxidative and Nitrative Stress
Contradicting (0)
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