Healing wounds with electricity
Some150 years ago, in a selfless display of commitment to science, German physiologist Emil Du-Bois Reymond made a wound in his own arm and measured the naturally occurring electrical field at the wound. Now an international team of researchers has uncovered the processes by which this electrical field controls the wound healing process, knowledge which could lead to the creation of new methods for treating wounds. When someone cuts themselves, a number of processes cause cells to move into the wound and start the repair work. These include cells moving until they make contact with each other, and wounded cells releasing chemicals that attract other cells. However, despite Dr Du-Bois Reymond's pioneering research, the role of electrical fields in wound healing remained largely unexplored, and even now only a few teams around the world are working in this area. Professor Min Zhao of the University of Aberdeen in the UK first became interested in the wound healing process while working as a trauma surgeon in his native China. Together with a team of researchers from Austria, Japan and America, he has discovered how the electrical field of a wound contributes to the healing process. Their findings are published in Nature magazine. Under normal conditions, cells in a culture move into wounds in a coordinated manner. However, when the team applied an electric field to the wound with a polarity that opposed the healing direction, the epithelial cells followed the direction of the electric signal and the wound opened up. When the team reversed the polarity of the electrical field, the wound closed. In addition to epithelial cells, other cell types which are crucial for wound healing, such as neutrophils and dermal fibroblasts, also moved in response to electrical fields, a process known as electrotaxis. The electrical fields of wounds are created by ion pumps or transporters, which move ions of positive or negative electrical charge in a particular direction. The researchers found that applying substances to the wound which increase the ion flow increased the electric field of the wound, and sped up wound healing. Conversely, the application of substances which inhibit ion flow decreased the wound's electric field and so impaired healing. Further experiments enabled the researchers to uncover the molecular pathways involved in the electrotactic response, and the genes controlling them. 'Scientifically, our findings offer a novel perspective in understanding how cells move to heal, and what genes and molecules the cells use to detect the electric fields,' commented Professor Zhao. 'Clinically, our findings offer a novel approach to speed up healing and to treat chronic wounds. These conditions are huge burdens personally and economically.' Professor Zhao and his team have identified several possible targets to develop new techniques to enhance and manage wound healing. They now hope to translate their results from the lab to the hospital and start clinical trials.
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