Light to illuminate the heart

2011/01/01 Elhuyar Zientzia Iturria: Elhuyar aldizkaria

• Bioteknologia
• Anatomia/Fisiologia
• Medikuntza

Two recently published articles have shown that optogenetics is a valid technique for investigating the development and functioning of the heart. This technique is based on two light-sensitive proteins (channelrhodopsin and halorhodopsin). They are actually proteins of some microorganisms, but researchers have managed to express themselves in neurons of laboratory animals. Proteins function as channels of light-sensitive ions, so using light pulses of different colors, researchers can control isolated neurons or brain circuits.

This technique has now been applied to the muscle cells of the heart. In fact, cardiomyocytes are activated by electrical potentials, ejected or introduced into the cell by ions. Therefore, they are suitable for applying optogenetics.

Normally, physiologists use electric currents to excite heart cells. But electricity produces toxic gases that alter the pH of cells. Therefore, researchers cannot excite cells for a long time. Thanks to optogenetics they have managed to overcome this problem.

One of the researches has been published in the specialized journal Nature Methods. In this research, mouse stem cells come out of mothers to get mice that express in the heart the protein channelrhodopsin. Through the pulses of blue light they have been able to simulate infarctions and arrhythmias.

The other research has been published in Science, where they have released their work with zebrafish. Fish have been genetically modified to express channelrhodopsin and halorhodopsin proteins in heart cells. Then, with orange light, they have controlled the heart cells accurately.

Both research is a useful example of optogenetics. In addition, researchers such as skeletal muscle have begun to use it not only in the brain and heart, but also in other organs.