Cholesterol and fats prime immune cells to clog arteries

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A fatty diet could change your genetic make-up, priming the immune system and causing clogged arteries.

Epigenetic changes – which often involve adding methyl to particular DNA sequences in a process known as DNA Methylation – can alter gene expression in response to environmental stimuli. The field of epigenetics has excited biologists because it allows animals to adapt their genetics to fit the environment, while also passing some of that experience on to the next generation.


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To understand how fats and cholesterol in the blood influence our immune system at the epigenetic level, Dr Bastiaan Heijmans from Leiden University Medical Center and his colleagues measured the epigenetic profiles of 3296 people, as well as the levels of triglycerides and two types of cholesterol – LDL and HDL – in their blood. The team analysed the DNA of white blood cells, and found six sites where epigenetic changes were caused by differences in triglyceride and cholesterol levels.

They found that higher blood triglycerides caused decreased methylation at two genomic sites and increased methylation at a third. Higher LDL cholesterol increased methylation at a fourth site, while higher HDL cholesterol levels caused decreased methylation at two further sites. In general, increased methylation reduces gene expression, by blocking access to the gene. DNA methylation at these six sites decreased the expression of two genes responsible for lipid production, and increased expression of two genes known to break down lipids.

All together, their results show that people with higher levels of triglycerides and LDL cholesterol (the bad kind, apparently) and low levels of HDL cholesterol (that’s the good kind), tend to express more genes for breaking down fats and exporting them out of the blood stream, and fewer genes for importing them in. This feedback mechanism means that high levels of fat in the blood lead to changes that reduce fat in the bloom – a pretty sensible system if you ask me.

However, these epigenetic changes could prime the immune cells to persistently change their ability to clear excess lipids. This could in turn affect atherosclerosis – a clogging of arteries driven by an accumulation of fat in the blood vessel walls that cannot be cleared away by immune cells, Heijmans says.

More research is needed to understand the link between cholesterol, fats, and immunological conditions like atherosclerosis.

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