Overactive bladder is a condition that affects millions of people and causes a frequent need to urinate, incontinence, and an increase in bladder voiding. A common treatment uses low levels of electricity to stimulate nerves controlling the bladder. Unfortunately, it’s not precise and can lead to off-target effects and pain. SPARC program awardee Dr. Aaron Mickle developed an innovative approach to this problem by creating a miniature implanted device that can sense and control bladder function in rats. This self-adjusting coordination of devices, that manipulate nerves to control organs, is called a closed-loop system.
Instead of activating nerves using electricity, Dr. Mickle and his team used a technique called optogenetics where genetically modified rat nerve cells could be activated using light. In rats, Mickle’s team inserted a stretch sensor that measured changes in bladder expansion over time. The sensor was connected to LEDs. Both were connected by wires to a flexible base-station device implanted in the abdomen. The bladder-stretch sensor communicated data to the base station, which wirelessly transmitted this information to an external device that recorded and monitored bladder function. Rats received the molecule cyclophosamide, which leads to frequent bladder emptying. When the external device detected this abnormal bladder function (i.e. signs of overactive bladder), it transmitted a wireless signal causing light-driven inhibition of nerves affecting bladder emptying—preventing abnormal frequency of urination.
Although the animal model of overactive bladder shows promise for this technology, questions remain about whether this approach could be used in humans or to treat other diseases. Additionally, the body’s long-term response to the stretchable sensor is unknown and there are other concerns about possible tissue damage or unintended adhesion to the tissue that affect the device’s function. However, if it ultimately proves fruitful, this work could correct organ dysfunction and manage pain.
Reference:
A wireless closed-loop system for optogenetic peripheral neuromodulation. Mickle, A. D., Won, S. M., Noh, K. N., Yoon, J., Meacham, K. W., Xue, Y., Mcllvried, A. L., Copits, B. A., Samineni, V. K., Crawford, K. E., Kim, D. H., Srivastava, P., Kim, B. H., Min, S., Shiuan, Y., Yun, Y., Payne, M. A., Zhang, J., Jang, H., Li, Y., Lai, H. H., Huang, Y., Park, S., Gereau IV, R. W., & Rogers, J. A. Nature (2019) 565(7739), 361.
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