A natural defence mechanism against heart disease
14 May 2010
The team of researchers from the University of Leeds identified a previously unknown protein in the cells of human blood vessels and found that it could be activated by a naturally occurring steroid hormone known as pregnenolone sulphate. In the laboratory, this activation lead to a reduction in the production of inflammatory cytokines - proteins that drive the early stages of heart disease.
In further collaborative studies with surgeons at Leeds General Infirmary, the team has shown that this defence mechanism can be switched on in diseased blood vessels as well as in healthy vessels in cell culture.
"The effect that we have seen is really quite exciting and also unexpected," said Professor David Beech, who led the study. "However, we are absolutely not endorsing any claims made by manufacturers of any health supplements. Evidence from human trials is needed first."
Pregnenolone is a steroid hormone that is sold widely as a health supplement, with purported benefits including improved energy, vision and memory. It is often referred to as a 'fountain of youth', although rigorous clinical trials are needed to determine its true safety and efficacy.
This type of steroid is different from anabolic steroids, which mimic the effect of the male hormone testosterone to promote muscle growth and have been linked to an increased risk of heart disease.
So-called 'fountain of youth' steroids are made naturally in the body, but levels decline rapidly with age. This has led to a market in synthetically made steroids that are promoted for their health benefits, such as pregnenolone and DHEA.
Pregnenolone sulphate is in the same family of steroids but is not currently sold as a health supplement.
"These 'fountain of youth' steroids are relatively cheap to make and some of them are already available as commercial products. So if we can show that this effect works in people as well as in lab-based studies, then it could be a cost-effective approach to addressing cardiovascular health problems that are becoming epidemic in our society and worldwide," Professor Beech added.
A chemical profiling study indicated that the protective effect of pregnenolone sulphate was not as strong when cholesterol was present too. This suggests that the expected benefits of such steroids will be much greater if they are used in combination with cholesterol-lowering drugs and other healthy lifestyle strategies such as diet and exercise.
The findings are published in the journal 'Circulation Research'.
Image: Digitally enhanced image of a model human heart. Credit: Gordon Museum, Wellcome Images
Reference
Naylor J et al. Pregnenolone sulphate- and cholesterol-regulated TRPM3 channels coupled to vascular smooth muscle secretion and contraction. Circ Res 2010 [Epub ahead of print].
