A biosensor that stimulates single heart cells to beat could help scientists to understand how lactate influences cell death during heart attacks. 

Biosensor to study heart cell metabolism

The quantity of lactate that a cell makes can show how healthy it is. Lactate is linked to a damaging decrease in blood pH, called acidosis, with damaged cells or those suffering from a lack of oxygen tending to produce more. Low oxygen levels occur in ischaemia, when the blood supply to the cell is restricted, which can happen during a heart attack. 

'The role of lactate in cell acidosis is at the heart of the question we are trying to answer, and may give us insights into the onset of cell death,' said Jonathan Cooper of the University of Glasgow, UK, whose team developed the device.

The team's sensor relies on an enzyme that converts lactate into pyruvate and hydrogen peroxide. The hydrogen peroxide produced is then oxidised at an electrode, which causes the electrical current to rise.

According to Cooper, the system could be used to test for new drugs to protect heart cells suffering low oxygen levels. As he explains, 'heart disease still is the most important area of unmet medical need in the western world.'  

Andrew Halestrap, an expert in lactate transport, at the University of Bristol, UK, called the research 'a major technical achievement.' However, he cautioned, the lactate electrode relies on oxygen to work, which is in short supply during ischaemia. If this can be solved 'exciting avenues of research will open up,' he added. Cooper's group will overcome the hurdle by using a model that deprives cells, but not the sensor, of oxygen. 

Rachel Warfield