Infrared light therapy for spinal cord injury recovery has reached an important milestone

Patients with spinal cord injury (SCI) may benefit from future treatments aimed at restoring nerve connections using red and near-infrared light.

The method, developed by scientists at the University of Birmingham, UK, and patented by University of Birmingham Enterprise, involves delivering light directly to the site of injury.

Recent research published in the journal Bioengineering and Translational Medicine has identified the optimal “dose” for this new therapeutic approach and shown that it can produce significant therapeutic improvements, including significant restoration of sensation and movement, and regeneration of damaged nerve cells.

Researchers led by Professor Zubair Ahmed used cellular models of SCI to determine the frequency and duration of light needed to achieve maximum functional recovery and stimulate nerve cell growth.

They found that delivering 660nm red light for one minute per day increased cell viability (a measurement of the number of living cells) by 45% over five days of treatment.

Professor Ahmed said: "Excitingly, this aspect of the study showed that the effect of 660nm light was both neuroprotective, improving nerve cell survival, and neuroregenerative, stimulating nerve cell growth."

The researchers also studied the effects of light therapy in preclinical models of SCI. Here, they used two different methods: an implantable device and transdermal delivery, in which a light source is placed on the skin.

Their study showed comparable results for both delivery methods: a dose of 660 nm light delivered daily for one minute for seven days resulted in reduced tissue scarring at the injury site and significant functional recovery.

The researchers also found a significant reduction in both cavities and scarring, as well as increased levels of proteins associated with nerve cell regeneration and improved connections between cells in the damaged area of the spinal cord.

This is the first time transdermal and direct light delivery have been compared in SCI, and the results are a major milestone for the researchers, who have already received additional funding and plan to develop an implantable device for use in people with traumatic SCI, where there are currently no treatments that preserve cells or improve neurological function.

Andrew Stevens, first author of the study and a neurosurgical registrar, explains: "Surgeries following spinal cord injury are routine, but currently these operations only aim to stabilise the damage to the bones of the spine caused by the injury. This concept is incredibly exciting as it could offer surgeons the opportunity to implant a device during the same operation that could help protect and repair the spinal cord itself."

Professor Ahmed continues: “To make light therapy viable for the treatment of SCI in humans, an implantable device will be needed to provide direct visibility of the damaged tissue and allow for greater precision and standardisation of dosage without being hindered by the thickness of the skin and other tissues surrounding the spinal cord.

Photobiomodulation (PBM) may provide a viable therapeutic approach using red or near-infrared light to promote recovery after SCI by attenuating neuroinflammation and preventing neuronal apoptosis. Our current research aims to optimize PBM dosing regimens and develop and validate the efficacy of an invasive PBM delivery paradigm for SCI."

The research team is now looking for commercial partners or investors to take the next steps in developing a prototype device that could be used in the first human clinical trials.