Summary: It is known that tendons have piezoelectric properties, meaning that tendon cells produce a weak electric current when stretched. However, a first-of-its-kind study shows that this piezoelectric current plays an important role in tissue regeneration.
Electrical stimulation therapies have long been used in sports medicine, with studies showing that such a therapy helps. However, its underlying mechanism remains poorly understood. However, one of the new experimental studies seems to provide sound evidence supporting electrical stimulation and its role in managing sports injuries, especially those of tendons and ligaments.
In the US, each year, about half a million adults report injuries of tendons. However, managing such injuries is quite challenging. Generally, it takes months for individuals to make a complete recovery.
Tendon injuries cause significant disability, as tendons are slow to heal. If there is a partial tear, it may take a few weeks to even months to make a complete recovery. However, a complete tear is quite challenging to repair and requires surgical intervention. But, even after surgical repair, it takes months to heal. Thus, there is a need to find ways to accelerate these healing processes.
This new study by the University of Galway and the University of Limerick suggests that electrical stimulation may be quite helpful. More importantly, this study could shed some light on the underlying mechanism, explaining how electrical stimulation may help.
Tendons are very robust and are made to resist massive mechanical stress. Muscles are attached to bones with the help of tendons, a kind of fibrous tissue. New studies have made some interesting discoveries that tendons are not just piezoelectric, but these currents play a vital role in the physiology of these tissues. It means that when tendons are squeezed or stretched, they produce electricity. This weak electric current produced by tendons plays a vital role in their physiology. It also means that tendons need the flow of this weak electric current to regenerate.
Researchers have been experimenting with human tendon-derived cells (hTDCs) in lab experiments. However, they have found that growing hTDCs is quite challenging. In this new study, researchers developed a special device or tympanic bioreactor. This bioreactor works by exerting mechanical vibratory force on cells grown in lab conditions and a mild electric current. Researchers found that the application of this mechanical stress and weak electrical current could considerably stimulate the growth of hTDCs.
Researchers say these findings have significant implications, as this technology or understanding can generate other tissues similar to tendons. Thus, for example, the role of this technology can be explored in growing cartilage cells, bones, and even cardiovascular tissues.
Science has long seen that the application of mechanical force is helpful in promoting healing in musculoskeletal conditions. This explains why physical therapy is so good when living with such conditions. However, now this new kind of study shows that applying electrical stimulation may have some added benefits in managing musculoskeletal conditions.
Finally, these new understandings must be used to develop novel approaches for managing chronic pain and promoting the growth of different tissues. These understandings can be used to create new methods in regenerative medicine.
Although science has long known that tendons have piezoelectric properties, this is the first study to show that these piezoelectric signals play a vital role in cell differentiation, tissue regeneration, and healing processes.
Frequently asked questions
Will a damaged tendon ever heal?
Yes, but slowly. Tendons are slow to heal, which is why tendon injuries cause so much disability. A partial tear can take a few weeks to several months to recover completely. A complete tear is much harder: it usually needs surgical repair, and even after surgery it takes months to heal.
What does it mean that tendons are piezoelectric?
It means tendons make electricity. When a tendon is stretched or squeezed, its cells produce a weak electric current. Scientists have known this for a long time. This study is the first to show that the current plays a vital role in cell differentiation, tissue regeneration and healing, so tendons need that flow of current to regenerate.
Does electrical stimulation help tendons heal?
Electrical stimulation has long been used in sports medicine, but how it works was poorly understood. In this study from the University of Galway and the University of Limerick, a device that applied vibration plus a mild electric current considerably boosted the growth of human tendon-derived cells in the lab. That points to why electrical stimulation can help injured tendons and ligaments.
What helps tendons heal faster?
Mechanical force has long been known to help musculoskeletal tissues heal, which is why physical therapy works so well for these conditions. This study adds electrical stimulation to that picture: combining mechanical stress with a weak current may give injured tendons an added benefit. The same approach could also be explored for growing cartilage, bone and even cardiovascular tissue.
Source:
Fernandez-Yague, M. A., Palma, M., Tofail, S. A. M., Duffy, M., Quinlan, L. R., Dalby, M. J., Pandit, A., & Biggs, M. J. (2024). A Tympanic Piezo-Bioreactor Modulates Ion Channel-Associated Mechanosignaling to Stabilize Phenotype and Promote Tenogenesis in Human Tendon-Derived Cells. Advanced Science, 11(45), 2405711. https://doi.org/10.1002/advs.202405711
Dr. Gurpreet Singh Padda, MD, MBA, MHP
