Conference News Update
Thousands of potential activators are present in these complex injuries, the researchers noted. By exploring signals that control the cells’ behavior at a specific time point in the injury, he and his colleagues are getting closer to zeroing in on which receptor on the cell surface to target to promote repair. Two receptors, TLR-2 and dectin-1, have been identified in this most recent work as critical in this environment. When both are activated, the macrophages perform damaging and reparative functions simultaneously in the spinal cord. But when only TLR-2 was stimulated, the cells retained their regenerative effect without creating a toxic environment. In contrast, when only dectin-1 was stimulated, nerve cells died.
An experimental compound used in the study was able to activate the TLR-2 receptor alone in cell cultures, enhancing growth of axons without causing cell death. When introduced to the spinal cords of rats, the compound caused inflammation, but little tissue damage. More investigation is needed, as it remains unknown exactly what starts this signaling process in the injured spinal cord.
“Now we have to go into the cell to figure out what part of that signaling process we can manipulate and if that manipulation can stop the toxicity,” Dr. Gensel said.
Ultimately, the researchers hope to identify a precise target for drug therapy that could alter the immune response after the devastating effects of the injury and tip the balance of macrophage activity toward nerve cell repair.
Brain Tissue Loss in Patients With Alzheimer’s Disease and Mild Cognitive Impairment
Patients with Alzheimer’s disease exhibit striking structural changes in the caudate nucleus, which is typically associated with movement disorders such as Parkinson’s disease, according to investigators.
“Our finding suggests that Alzheimer’s disease produces broader damage in the brain than previously thought, including damage to areas not usually associated with the disease,” said lead author Sarah Madsen, a graduate student working with Paul Thompson, PhD, of the University of California, Los Angeles.
For the study, Ms. Madsen and her colleagues analyzed the brains of 400 elderly participants. Of this group, 100 were healthy, 100 had been diagnosed with Alzheimer’s disease, and 200 had mild cognitive impairment.
Compared with healthy individuals, the caudate nucleus was 7% smaller in those with Alzheimer’s disease and 4% smaller in those with mild cognitive impairment. It was also smaller in older and in overweight individuals.
“Our finding suggests a gradual progression of brain tissue loss in the caudate nucleus as dementia becomes more severe,” said Ms. Madsen. “This brain area, which is associated with certain forms of learning and memory as well as motor control, is an important factor to consider when studying Alzheimer’s disease and in predicting how the disease will progress,” she said.
Some Children With Spinal Cord Injury May Be Overlooked for Walking Rehabilitation
The traditional way to predict whether children can regain movement after spinal cord injuries may exclude a small subset of patients who could benefit from therapy, according to two studies presented by researchers from the University of Florida.
In one study, the investigators presented details of a child with incomplete spinal cord injury who continues to improve four years after recovering walking ability in a locomotor training program, even though clinical assessment tools predicted he would never walk again.
In another presentation, the researchers discussed fi ndings in which three of six children with severe, chronic, and incomplete spinal cord injuries—patients who retain some sensation or movement below the injury—improved through locomotor training, to the point where they could take steps. Even the three who did not regain stepping ability acquired greater trunk control.
The research was part of the Kids Step Study, led by Andrea Behrman, PhD, Associate Professor of Physical Therapy in the College of Public Health and Health Professions, and Dena Howland, PhD, Associate Professor of Neuroscience with the College of Medicine. “The prevailing clinical view is patients who are able to recover need to display early leg movement,” said Dr. Howland. “The children in our studies displayed minimal or no movement, yet some were still able to make significant improvement.”
One study participant was a 4-year old boy who received a disabling cervical spinal cord injury at age 3. Before he began in the locomotor training program, his lower extremity motor score predicted he would not recover walking. He had not walked for the 16 months since his injury. Then, for 76 sessions, the child participated in the program of locomotor training run by Drs. Behrman and Howland and their research team. The training takes a task specific, intense repetitive practice approach with the goal of activating the neuromuscular system essential for walking.
