Paralyzed man recovers some function following transplantation of OECs and nerve bridge

Putnam Valley, NY. (Oct. 21, 2014) – Treating patients with a complete spinal cord injury (SCI), the condition in which no motor or sensory function is preserved in the spinal segments below the level of the injury, has generally been unsuccessful. This is because no treatment methods have been able to regenerate the severed spinal nerves across the injured area. Now, doctors in Poland and scientists from England may have restored some function and sensory sensation to a 38 year-old man who had sustained a traumatic transection (severing) of the spinal cord in the upper vertabral level Th9. By removing one of his olfactory bulbs, where the sense of smell resides, and transplanting his own olfactory ensheathing cells (OECs) and olfactory nerve fibroblasts (ONFs) into the damaged area along with a nerve "bridge" constructed between the two stumps of the damage spinal column, they have seen some voluntary limb function and sensation recovery over a 19 month follow-up.

The study will be published in a future issue of Cell Transplantation and is currently freely available on-line as an unedited early e-pub at: http://www.ingentaconnect.com/content/cog/ct/pre-prints/content-CT-1239_Tabakow_et_al.

The American Spinal Injury Association's (ASIA) international classification of spinal cord injury is widely used to document and classify sensory and motor impairments following SCI. Stages of impairment are based on neurological responses, touch and pinprick sensations, and the strength of the muscles that control ten key motions on both sides of the body.

Traumatic spinal cord injury is classified into five categories on the ASIA Impairment Scale. "A" indicates a "complete" spinal cord injury where no motor or sensory function is preserved in the sacral segments S4-S5. "C" indicates an "incomplete" spinal cord injury where motor function is preserved below the neurological level and fewer than half of the key muscles below the neurological level have a muscle grade of 3 or more.

"After OEC transplantation and the building of the nerve bridge, this patient improved from ASIA A to ASIA C," said Dr. Pawel Tabakow of the Department of Neurosurgery at the Wroclaw Medical University in Wroclaw, Poland. "Prior to the transplantation, we estimated that without this treatment, our patient's recovery chances were less than one percent. However, we observed a gradual recovery of both sensory and motor function that began four months after the surgery."

OECs are a type of cell that resides in both the peripheral and central nervous system. Together with ONFs, they make bundles of nerve fibers that run from the nasal mucosa to the olfactory bulb where the sense of smell is located. Prior studies with animals had suggested that OECs from the olfactory bulb had greater regeneration powers than OECs from the nasal mucosa. The technique of bridging the sectional spinal cord using autologous (derived from the patient) sural nerve grafts has been used in animal studies for three decades, but never in combination with OECs, commented the doctors.

"The OECs and the ONFs appeared to work together, but the mechanism between their interaction is still unclear," said Dr. Geoffrey Raisman, Professor at the Spinal Repair Unit, Department of Brain Repair and Rehabilitation, UCL Institute of Neurology, London, UK.

The doctors noted that further laboratory studies would be needed to better understand the interactive properties between the human OECs and ONFs within the nerve bridge.

"Our results in treating the first patient with a complete spinal cord injury with transplanted bulbar OECs and ONFs and the reconstruction of the spinal cord gap with nerve implants are very encouraging," concluded the medical team. "However, our results need to be confirmed in a larger group of patients with a similar injury. In the meantime, we are investigating surgical techniques for more minimally invasive access to the olfactory bulb."

Source: Cell Transplantation Center of Excellence for Aging and Brain Repair