Elevated levels of high-density lipoprotein may not be beneficial for the heart.
A new discovery about the way cholesterol is eliminated from the body could lead to drastically different treatment options, according to a study published by Arteriosclerosis, Thrombosis, and Vascular Biology.
The authors discovered a new component of the cholesterol elimination pathway that challenges the widely-accepted convention of how quickly humans eliminate cholesterol.
While the initial purpose of the study was to confirm current beliefs about cholesterol transport, the authors made a very different discovery.
“The model people have been using for 40 years presumed that cholesterol was transported from the arteries with other lipids and proteins and entered a particle that stayed in the blood for several days before being cleared by the liver for disposal,” said researcher Henry Pownall, PhD. “What we discovered in the process was something different. We discovered the cholesterol skips all these steps and goes directly from this early particle to the liver in 2 minutes. This is a thousand times faster than what was formerly suspected.”
A majority of studies look at high-density lipoprotein (HDL) cholesterol in its mature form, but the authors studied nascent HDL.
The authors found that nascent HDL goes directly to the liver and completely skips maturation, which was previously unknown, according to the study.
Based on these results, the authors hypothesize that current methods of treating high low-density lipoprotein (LDL) cholesterol for cardiovascular health may be incorrect.
Instead, the authors suggest that a better understanding is needed of how HDL contributes to heart disease and how to increase it to benefit the heart since patients with high HDL levels may be at risk, according to the study.
“LDL cholesterol, the so-called ‘bad cholesterol’ is well controlled with the current statin therapies. The track record for these cholesterol-lowering drugs is indisputable, and they will continue to work,” Dr Pownall said. “HDL, or the ‘good cholesterol,’ however, is a much trickier system. Not everything that raises it protects the heart and not everything that lowers it is bad for you. We will need to redesign new drugs to lower plasma cholesterol in a way that takes into account this new mechanism. We will look for interventions — maybe dietary, maybe pharmacological – that raise HDL cholesterol in a way that helps protect the arteries and prevent cardiovascular disease.”