Researchers from The Ohio State University, Nationwide Children’s Hospital and the University of Bern in Switzerland found that protein replacement gene therapy helped stabilize an animal model of spinal muscular atrophy.
Spinal muscular atrophy (SMA) is the leading genetic cause of infant death, but until now had not been modeled in a large animal to predict human outcomes. The disease is caused by an abnormal or missing survival motor neuron gene 1 (SMN1) and retention of the SMN2 gene. The genes produce the SMN protein, however SMN2 produces considerably less than SMN1, causing motor neurons in the spinal cord to degenerate.
The researchers found that correcting levels of the SMN protein prior to symptom onset resulted in complete correction of the disease, while correction of SMN levels while the animal showed symptoms resulted in a marked correction and no further motor neuron loss.
Although remaining motor neurons are capable of sprouting and improving muscle function following early intervention gene therapy, neurons lost cannot be restored.
“We also showed that the biomarkers of motor neuron function that can be used in both man and pig show a marked response to treatment, and will have predictive value in human clinical trial assessment,” said Arthur Burghes, PhD, a professor and researcher in the Department of Molecular and Cellular Biochemistry at Ohio State’s College of Medicine, in a press release.
The researchers are now beginning a phase I trial of the gene therapy in SMA patients.