Good Cholesterol May Actually Be Bad For Your Heart

Posted: Mar 12 2016, 8:38am CST | by , Updated: Mar 16 2016, 3:42am CDT, in News | Latest Science News


Good Cholesterol May Actually be Bad for Your Heart
HDL, or 'good' cholesterol, can remove cholesterol from arteries and shuttle it to the liver where it is eliminated, but this process can be disrupted in certain circumstances (such as deficiency of SCARB1). Credit: The lab of Daniel Rader, MD, Perelman School of Medicine, University of Pennsylvania
  • Elevated HDL cholesterol believed to be good may be bad for heart!

A study conducted at the University of Pennsylvania shows a certain genetic cause of elevated HDL-C may be harmful.

A new study suggests a form of genetically elevated 'good' cholesterol may actually be bad. It is generally accepted that high levels of HDL cholesterol (HDL-C) is good.

A recent study conducted at the University of Pennsylvania has challenged the conception. The international study was led by researchers from the Perelman School of Medicine at Penn.

The study shows a certain genetic cause of increased HDL-C may actually be bad for health. A specific mutation in a gene binds to HDL and prevents the receptor from functioning.

The genetic mutation causes an increased risk of coronary heart diseases. The findings of the study have been published in the journal Science

Previously research also found out HDL might not be protective against heart diseases as believed. Several clinical trials of HDL-raising drugs showed little or no effect.

Daniel J. Rader is MD and chair of the department of Genetics at University of Pennsylvania. Rader is also the lead author of the study. According to Rader, their results indicate some causes of raised HDL actually increase risk for heart disease.

The current study is also the first demonstration of a genetic mutation that raises HDL but increases risk of heart disease. It leads to the belief HDL may not directly protect against all heart diseases. 

In the current study Rader and his team sequenced lipid-modifying regions of the genomes of 328 people. All the subjects had markedly elevated HDL.

Control groups with lower levels of HDL were also used in the study. The study was aimed to identify the genetic causes of high HDL. The researchers found the SCARB1, which encodes for Scavenger Receptor B1 (SR-B1).

The SCARB1 is a major receptor for HDL on cell surfaces. The team found a person without any SCARB1 function along with extremely high HDL-C level. The person was found to have two copies of a SCARB1 mutation called P376L. The mutation caused a breakdown in HDL receptor function.

They also found people with only one copy of the SCARB1 P376L mutation have significantly higher HDL-C levels. The researchers thought the SCARB1 P376L mutation, might increase the risk of heart disease.

Despite the mutation raising HDL levels it could be harmful. In short the researchers have raised the issue whether HDL Cholesterol actually means good or bad for heart. The researchers then collaborated with other globally to further probe the issue. 

The team plans to characterize and test other SCARB1 mutations for their relationship to HDL levels and heart disease. The team believes other genes may have similar effects.

The team also found the P376L mutation in SCARB1 appears to be specific people of Ashkenazi Jewish descent. So testing in this particular ethnic group might be important. 

Rader also suggested a therapeutic approach increasing expression of SCARB1 could reduce heart diseases. As a result the approach would reduce HDL blood levels.

The research also demonstrated the protective effects of HDL are more dependent on it functions than the levels. Rader concluded they still have a lot to learn about the relationship between HDL function and heart disease risk. 

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The Author

<a href="/latest_stories/all/all/20" rel="author">Sumayah Aamir</a>
Sumayah Aamir (Google+) has deep experience in analyzing the latest trends.




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