Diabetes can accelerate the
development of atherosclerosis, a
condition in which the arteries harden.
According to a new study in mouse
models, increasing the levels of some
forms of cholesterol could help treat this
condition.

New research suggests that increasing levels of
better quality 'good' cholesterol could make all the
difference in fighting atherosclerosis.
Research has shown that people with diabetes have
a higher risk of developing atherosclerosis , a
condition in which the arteries harden because of
plaque buildup. Atherosclerosis can lead to stroke
or heart attack .

Specialists believe that this may be because of
increased levels of low-density lipoprotein (LDL)
cholesterol, which tends to build up on the walls of
blood vessels, and lowered levels of high-density
lipoprotein (HDL) cholesterol, which acts as a
vehicle carrying excess cholesterol molecules to the
liver, which filters it out.

For this reason, people often refer to LDL as "bad"
cholesterol and HDL as "good" cholesterol.
In a new study, researchers from the New York
University School of Medicine have decided to find
out whether increasing HDL levels could fight
atherosclerosis in the context of diabetes. For this
purpose, they used mice that had diabetes, as well
as atherosclerosis.

Their research — which appears in the journal
Circulation — focused on what they term "functional
HDL," which is HDL that actively promotes
cholesterol efflux (the extraction of cholesterol from
cells).

Functional cholesterol measures how good HDL is
at moving excess cholesterol out of and away from
the walls of blood vessels. The researchers argue
that this is a more useful approach than just
looking at how much HDL cholesterol an individual
has in their blood.

"Our study results argue that raising levels of
functional good cholesterol addresses inflammatory
roots of atherosclerosis driven by cholesterol
buildup beyond what existing drugs can achieve,"
says senior author Dr. Edward Fisher.
"Good cholesterol is back as a therapeutic target
because we now understand its biology well enough
to change it in ways that lower disease risk," he
continues.

'The basis for new kinds of
treatments'
The investigators explain that their approach derives
from previous studies that show that specific
molecular mechanisms related to high blood sugar
can both lower the level of HDL in the blood and
render HDL dysfunctional.

In the current study, the investigators raised the
levels of functional HDL in mice with diabetes and
atherosclerosis by increasing the amounts of the
protein apolipoprotein A-I (apoA-I), which is a key
component of HDL.

They did so through two different approaches: either
by genetically engineering mice to boost apoA-I
production or by injecting apoA-I into their
bloodstream.

These interventions helped increase functional HDL
levels, and the scientists found that this boosted
the reversal of atherosclerosis by 30% in mice that
had also received a treatment to lower LDL levels.
The researchers saw that the increase in functional
HDL worked by reducing inflammation in
atherosclerotic plaques by about half.