Dr. Jason Johnson awarded BHF Fellowship
BHF Intermediate Fellowship Award to investigate causes and prevention of heart attacks and strokes.
Dr. Jason Johnson (Bristol Heart Institute) has just been awarded a major Fellowship form the British Heart Foundation (BHF). The Fellowships are awarded to outstanding young scientists to help them become independent researchers. Dr. Johnson was awarded over £365K for 4 years, which includes salary for a technician.
Dr. Johnson said of the award: "I was delighted when I heard the application had been successful: it is the first step towards establishing my own research group; something I have been aiming for since receiving my PhD in 2005".
Dr. Johnson’s research focuses on the process of atherosclerosis – the build up of fatty material on the lining of arteries to form “plaques” that can partially block the artery and reduce blood flow. Heart attacks and strokes are primarily caused by cracking of these plaques, which triggers formation of a blood clot that can completely block the blood vessel – starving the heart or brain of blood and oxygen. Exactly what causes the plaques to rupture is not known, and forms the basis of Dr. Johnson’s Fellowship.
The fatty material forming the plaque (blockage) consists of different types of cell, and one type of cell, macrophages, may contribute not only to plaque formation, but also to their cracking.
Dr. Johnson recently found that the macrophages exist in several forms that are both good and bad with respect to plaque formation and cracking. The bad macrophages have an increased capacity to grow and divide into more cells so increasing the size of the plaque, but may also trigger death of smooth muscle cells that normally stabilise the plaques. Thus the bad macrophages “destabilise” the plaques, and promote cracking.
Over the next four years, Dr. Johnson will investigate why some plaques have a high number of the “bad” macrophages, and also hopes to identify markers in blood and tissues that may reveal whether a patient is at risk of plaque rupture, and hence of having a heart attack or stroke. He has already found that the bad macrophages contain high levels of a particular enzyme (matrix metalloproteinase 12 – MMP12), which might not only be one of the causes of plaque cracking, but also serve as a marker for it.
Dr Johnson says: “If we could find a marker that indicated the presence of unstable plaques – ones that are likely to rupture - then patients thought to be at risk of heart attacks or stroke could be tested for presence of the marker by assays performed on blood and tissue samples or by novel imaging modalities, and protective measures undertaken. For example, anticoagulant treatment to prevent clotting following rupture, but we are also investigating methods of stabilising the plaques to prevent rupture in the first place".