Study shows damage to previously unknown liver protein leads to heart disease, fatty liver.
There has been much focus on how to prevent heart disease by regulating the secretion of very low density lipoproteins (VLDL) by the liver. These lipoproteins are known to increase cholesterol levels, a risk factor for plaque buildup in the arteries. For healthy liver function, normal VLDL secretion must be kept in a delicate balance. Too little VLDL secretion causes fatty liver and, potentially, liver cancer. Identifying the protein and what activates it is the first step in finding ways to prevent its malfunction and disease. Now, a study from UCF College of Medicine identifies a tiny liver protein that when disrupted can lead to cardiovascular disease, as well as fatty liver disease. The team state that the chief culprit in disabling the protein’s delicate mechanics is a fatty acid found in red meat and butter.
Previous studies show that the transport of VLDL particles from the endoplasmic reticulum to the Golgi determines their secretion by the liver and is mediated by a specialized endoplasmic reticulum-derived vesicle, the VLDL transport vesicle. Earlier studies from the lab identified how newly formed VLDLs are transported into the blood stream, forming plaque. The current study identifies a tiny protein, called a Small Valosin-Containing Protein Interacting Protein (SVIP), that regulates how much VLDL is secreted into the blood.
The current study shows that SVIP in the liver must be regulated properly to ensure optimum health. Results show that the SVIP protein contains a binding site for myristic acid, a saturated, 14-carbon fatty acid that occurs in butterfat and animal fats, especially red meat.
Based on that finding, the group studied the effects of different dietary fats, including myristic acid, on the functioning of SVIP. Data findings show that only myristic acid activated SVIP to secrete excess very low-density proteins into the blood. Results show that when myristic acid is absent the liver failed to secrete any VLDL. The researchers state that caused fats to build up in the liver, which can lead to cancer.
The team surmise that their findings suggest high levels of myristic acid in the diet, through animal and dairy fats, keep SVIP from properly regulating the liver’s secretion of VLDL. For the future, the researchers state that their findings suggest diet modulates the complex molecular processes that have profound effects on a person’s health and lifespan. They conclude that the challenge will be to create a therapy that doesn’t impact the liver’s many other functions.
Source: UCF College of Medicine