If you read our articles, you’ve certainly heard of the genome, the epigenome and the proteome. They refer, respectively, to the genetic code, modifications to the DNA molecule outside of the genetic code, and to the ensemble of proteins within the body. These ‘omes’ all undergo changes during ageing and are likely to play an important role in our approach to rejuvenation. You may also have heard of the metabolome and the transcriptome, but we think there’s a good chance you haven’t heard of the electrome.
We all know that our central nervous systems run on bioelectricity – tiny electrical currents that form the basis of nervous communication. This is possible thanks to special proteins within the membranes of neurons. These proteins pump ions – atoms with a positive or negative charge – across the cell’s membrane. This generates an electrical charge across the membrane, which can then be released in order to trigger various events within the cell. This release of charge spreads like a wave from one end of a neuron to the other, and it’s how electrical information is carried long distances within the brain and body, say a signal from the motor cortex telling a muscle fibre to contract.
Yet neurons aren’t the only cells that possess this electrical charge. Virtually all cells in the body generate an electrical potential, be they red blood cells, skin cells or bone cells. In fact, we are electrical beings down to the molecular level, with many individual proteins depending on the exact placement of their own positive and negative charges in order to function correctly.
All these electrical charges have a collective name: the electrome.
The electrome shares several similarities with other ‘omes’ when it comes to the ageing process. Throughout life, cells accumulate genetic mutations at random, while the DNA and its associated proteins accumulate other modifications that change how the genetic code is read. This causes the identity of each cell (whether a cell behaves as a muscle cell or a white blood cell, for example) to slowly drift. This won’t turn one cell type into another, but it will make the cell less effective at doing what it is supposed to do.
Likewise, cells also have an ‘electrical identity’ that can be disrupted over time. Different cell types maintain slightly different electrical charges across their membranes. As we age, these electrical charges change, making some cells more ‘excitable’ and others less so.
As you might expect, this could have implications for the ageing brain and central nervous system. Changes in resting membrane potential have been observed in various cell types and regions of the brain during normal ageing, which could contribute to cognitive decline and neurodegeneration. However, the central nervous system is not the only system in the body that relies on bioelectricity.
It turns out that electricity is also involved in the wound healing process. When cells are torn open in an injury, the electrical charges across their membranes break down. This release of charge generates an electric field that attracts specialised cells to the site of the injury in order to begin repairing the tissue. This electric field seems to be quite important. Animal experiments have found that by strengthening or weakening this electric field through using drugs, wound healing can be significantly accelerated or slowed. In humans, experiments have shown that faster healing wounds are associated with a greater electrical field, and also show that the strength of this field tends to decrease with advancing age.
Cancer is a disease of ageing that shares many of the characteristics we believe to be responsible for general age-related decline. Cancer cells accumulate many genetic mutations, can lose their epigenetic identity, and release harmful signalling molecules that cause damage to nearby cells. As in the case of ageing, cancer cells also lose their electrical identity. Cancer cells develop different membrane potentials to normal cells, and this seems to help them to grow and spread. Scientists discovered this over a century ago, and physicians were even using electrical measurements in order to detect cancer. However, the study of the electrical properties of cancer were largely eclipsed by genomics, with the understanding that genetic mutations were the underlying cause of cancer development.
Considering the role of electricity in these rather important biological processes, is there any evidence that we can manipulate bioelectricity to treat disease in humans? The answer is yes, and the evidence is quite promising. Meta analyses suggest that the application of electric currents can accelerate healing in certain types of wound. Scientists are working on devices that could be incorporated into bandages to enhance the electric fields generated by the wearer. One such device has demonstrated great effectiveness in animals.
What about cancer? There is some evidence that restoring normal electrical activity to cancer cells can shut down their uncontrolled multiplication. Researchers used gene therapy to insert new ion channels in into cancer cells in tadpoles, and found that this was enough to prevent or reverse tumour development. Cancer cells have high energy demands, and electrical changes seem to be involved in reprogramming their metabolism. Electrical changes may also help cancer cells influence the cells around them to assist their growth and spread. For example, electrical currents can encourage blood vessel formation, something usually reserved for wound healing.
Electrical currents pervade our bodies, yet we know surprisingly little about them. The human genome may have been sequenced, but the electrome is very much incomplete, and could play a larger role in health and ageing than most people acknowledge.
Title image by Johannes Plenio, Upslash
Nature's Electric Potential: A Systematic Review of the Role of Bioelectricity in Wound Healing and Regenerative Processes in Animals, Humans, and Plants https://doi.org/10.3389/fphys.2017.00627
Electrometric Studies in Women With Malignancy of Cervix Uteri https://doi.org/10.1126/science.105.2721.209.b
High Voltage Monophasic Pulsed Current (HVMPC) for stage II-IV pressure ulcer healing. A systematic review and meta-analysis https://doi.org/10.1016/j.jtv.2018.08.003
Highly Effective Wound Healing Enabled by Discrete Alternative Electric Fields from A Wearable Nanogenerator https://nanoscience.engr.wisc.edu/paper/2018/18_ACSN_2_s.pdf
Cancer reversed in frogs by hacking cells' electricity with light https://www.newscientist.com/article/2081030-cancer-reversed-in-frogs-by-hacking-cells-electricity-with-light/