A research team led by Prof Kai Liu, Assistant Professor from the Division of Life Science at the Hong Kong University of Science and Technology (HKUST), has successfully found a way to stimulate the growth of corticospinal tract (CST) axons, nerve fibres that control voluntary motor functions, spell the dawn of a new beginning on chronic spinal cord injury (SCI) treatments. The groundbreaking discoveries have been published in The Journal of Neuroscience.
Patients inflicted with spinal cord injury would often suffer a loss of mobility, sensation, and interferes with activities of daily life dramatically. With millions of people living with paralysis globally, every year, there are recorded 20-40 new cases per million in Hong Kong, Taiwan, Europe, and USA. While physical therapy and rehabilitation would help the patients to cope with the aftermath, axonal regrowth potential of injured neurons, including corticospinal tract, was thought to be intractable, particularly with patients suffering chronic spinal cord injury (injured longer than 1 year).
Prof Liu’s research team recently demonstrated that the deletion of the PTEN gene would activate another gene, mTOR, which drives axons to regenerate and reform connections. The team initiated PTEN deletion on mice with a severed CST. Similar treatment procedures were carried out on a second group 1 month after severe spinal cord injuries, and a third group after 12 months. The team recorded a regenerative response of CST axons in all three models—showing that PTEN deletion stimulates CST axon sprouting and regeneration, even though the injury was sustained a long time ago.
Axons transmit information to different neurons, muscles, and glands; as bundles they help make up nerves. Regeneration of Axons would be an important first step towards a recovery for many suffering from SCI. Prof Kai Liu said, “The regeneration of CST axons has been a major challenge in the field, especially after chronic injuries.” He added that most manipulations so far have been done on acute or subacute injury models, and this is the first time where CST axonal regeneration in chronic lesion has been found.
Prof Kai Liu received his Bachelor’s degree from Peking University, and obtained his PhD in Neuroscience from Rutgers University. He worked at the Boston Children’s Hospital of the Harvard Medical School before joining HKUST in 2011.