Wilson da Silva, Sydney
BY GROWING heart cells in the laboratory, scientists have discovered clues to how fish oils help prevent heart attacks. It seems that fatty acids in the oils team up with the cells to keep the heart beating steadily.
Past clinical trials and epidemiological trials on human populations, particularly Inuits, have suggested that some fatty acids—especially those in fish oils such as eicosopentanoic acid and docosahexanoic acid—are particularly useful in reducing the risk of heart attack.
“What we wanted to do was focus at the cellular level at what was happening with these fatty acids,” says Ted McMurchie of the Division of Human Nutrition at CSIRO, Australia’s national research organisation.
Along with his colleague Wayne Leifert, McMurchie developed a technique for growing heart cells of adult mice in culture at their Adelaide labs. They stimulated individual cells with a weak electrical current so that they were beating regularly. By adding adrenaline, the team could make the cells beat out of rhythm with the electrical pulses. This mimics “arrhythmia”, the irregular beating that can bring on a heart attack.
McMurchie and Leifert then added food extracts, including fish oils, to the cultures, and observed their effects on the cells through a microscope linked to image enhancement systems.
It turned out that the fish oils could restore the beat to normal so that it was in time with the electrical pulses. They seemed to do this because their fatty acids become part of the membrane of each cell, which is itself made from fatty materials called lipids and contains components which control the cell’s beating. “They get absorbed into the cell and work on the cell membrane, influencing the signalling systems that control rhythmicity,” says McMurchie.
The researchers announced the results at last week’s 4th International Congress of Essential Fatty Acids and Eicosanoids in Edinburgh. McMurchie hopes that the team’s techniques will allow researchers to find other food extracts that have potential for preventing heart attacks.