Photosynthesis may help treat heart disease: study

BOSTON:��Stanford scientists have found that using blue-green algae and light to trigger photosynthesis inside the heart could help treat cardiac disease, the top cause of death globally.

����������� Researchers injected a type of bacteria into the hearts of anaesthetised rats with cardiac disease. Using light to trigger photosynthesis, they were able to increase the flow of oxygen and improve heart function.

����������� "The beauty of it is that it's a recycling system," said Joseph Woo, from Stanford University in the US.

����������� "You deliver the bacteria, they take up carbon dioxide, and with energy from the light, they form oxygen," Woo said.

����������� The genesis of this somewhat mind-boggling concept sprang from scientists searching for new ways to deliver oxygen to the heart when blood flow is restricted, Woo said.

����������� This condition, known as cardiac ischemia, is most often caused by coronary artery disease.

����������� "In nature, humans exhale carbon dioxide and plants convert it back to oxygen. During a heart attack, the muscle is still trying to pump. There's carbon dioxide but no oxygen," said Woo.

����������� "We wondered if there were any way to use plant cells and put them next to heart cells to produce oxygen from the carbon dioxide," he said.

����������� Researchers first tried grinding up spinach and kale and combining each with heart cells in a dish, but the chloroplasts - the photosynthetic organs - of those plants were not stable enough to survive outside of the plant cell.

����������� Next, they tried photosynthetic bacteria, referred to as cyanobacteria, or blue-green algae, since it has a more rugged structure necessary for living in water.

����������� They repeated the same tests to see whether these photosynthetic bacteria had the ability to survive with heart cells in a dish.

����������� The next round of experiments involved injecting the cyanobacteria into the beating hearts of anaesthetised rats with cardiac ischemia.

����������� They then compared the heart function of rats with their hearts exposed to light (for less than 20 minutes) to those who were kept in the dark.

����������� "The group that received the bacteria plus light had more oxygen and the heart worked better," Woo said.

����������� The bacteria dissipated within 24 hours, but the improved cardiac function continued for at least four weeks, he said.

����������� The researchers plan to investigate how to apply this concept to humans and how to deliver a light source to the human heart. They are also examining the potential of using artificial chloroplasts to eliminate the need for bacteria. (agencies)