GTx presents quality of life results from Ostarine Phase IIb study in cancer cachexia patients at ASCO 2010

March 28, 2017

Dr. Hedrick, who primarily researches the high correlation between diabetes and heart disease, began studying the ABCG1 protein several years ago as she looked at cholesterol buildup and coronary plaque formation in diabetes sufferers. "The primary, known function of ABCG1 is to remove excess cholesterol from the body. But with this study, we have discovered a new function for the ABCG1 protein. We now know that it is also very important for transport of cholesterol to various membranes within beta cells and, most likely, within other cells," she said. "Everybody thinks cholesterol is bad. But actually, scientists have long known it is an essential component of all cell membranes."

Dr. Hedrick and her team at the University of Virginia had heard of studies in diabetes mouse models showing that islet beta cells contained excessive cholesterol. "We wondered if this was somehow related to ABCG1, since its function is to remove excess cholesterol from the cells of the body," she said. "So we decided to investigate."

It was a novel idea, since ABCG1 was only known to sit on the plasma membrane of cells and no one had studied ABCG1 function within cells. "One surprising finding from our work is that ABCG1 action in beta cells is actually intracellular," said Dr. Sturek of the University of Virginia. "We found that the majority of ABCG1 actually sits inside the beta cell and that it's really important for delivering cholesterol intracellularly to the insulin granule membranes. Without delivery of cholesterol to these membranes by ABCG1, the insulin granules do not develop or function properly and, as a result, release significantly less insulin. This is particularly interesting because it suggests that we look at intracellular roles for ABCG1 in other cell types."

In previous studies, Dr Hedrick and her team had also made the finding that people with type 2 diabetes have relatively low levels of ABCG1. "We theorized that this contributed to higher rates of heart disease among type 2 diabetics since failure to successfully remove cholesterol from arteries can lead to arterial plaque buildup, a key contributor to heart disease."

Based on this latest research, Dr. Hedrick believes that boosting the levels of ABCG1 in diabetes patients may benefit sufferers in two ways - by aiding in reducing arterial plaque buildup and in improving insulin production.

Source: La Jolla Institute for Allergy and Immunology