Uncovering the actions of oestrogen in heart rhythm control

The effect of oestrogen on the function and local environment of the L-type Ca2+ channel (Miss Alice Francis)

Heart failure affects hundreds of thousands of people in the UK. It occurs when the heart lacks the power to pump strongly, and also becomes prone to dangerous abnormalities in heart rhythm. Studies have shown that progression of the disease and patients’ survival differs markedly between men and women, and that oestrogen, a female sex hormone, slows the development of heart failure. The reasons for this are unclear, so this team are carefully examining the effect of oestrogen in heart cells. With previous funding from the BHF, Dr Macleod’s team discovered that the long-term absence of female sex hormones leads to changes in the cell systems that control heart rhythm. A heart beat – when heart muscle cells contract strongly together – is stimulated by the spreading of an electrical wave across the heart. The team believes that oestrogen is important in ensuring that the heart muscle has the correct molecular machinery in place to sense and respond to this electrical activity. Now they will test this theory with detailed studies of heart cells. By uncovering the exact actions of oestrogen in heart cells, and determining the changes when oestrogen is absent, this research will provide clues to the gender differences seen in heart failure. It may also lead to the design of medicines inspired by oestrogen that could prevent or slow the onset of the disease in both sexes.