Paper Showing Direct CNS Delivery of Gene Therapy Provides Enhanced Protection in a Severe Mouse Model of SMA.
January 18, 2012.
Gene replacement strategies have shown great promise in animal models of SMA. In this current study, the Lorson Laboratory used self-complementary Adeno Associated Virus expressing full-length SMN (scAAV9-SMN) to compare two different routes of viral delivery in a severe SMA mouse model. This was accomplished by injecting scAAV9-SMN vector intravenously (IV) - often referred to as systemic delivery, or intracerebroventricularly (ICV) - direct CNS delivery, into SMA mice.
Both routes of delivery resulted in a significant increase in lifespan and weight compared to untreated mice with a subpopulation of mice surviving more than 200 days. However, the ICV injected mice gained significantly more weight than their IV treated counterparts. Likewise, survival analysis showed that ICV treated mice displayed fewer early deaths than IV treated animals. Also, animals receiving ICV injections also had higher SMN protein levels in the brain and lumbar spinal cord as compared to IV injected animals.
From these results, the authors conclude that the route of injection for scAAV9-SMN has a significant impact upon the degree of rescue and sheds light upon the development of disease and potential therapeutic implications. Intrathecal injections, a safe route for direct CNS delivery in humans, has recently been shown to result in efficient motor neuron transduction when using AAV9, including in a study from the Boulis laboratory using pigs and in a study funded by Families of SMA in the Kaspar laboratory using primates.
Thus, the authors of the Lorson paper conclude that intrathecal delivery may prove to be a desirable route of administration should AAV gene therapy for SMA reach clinical trials ,and; collectively, this study demonstrates that route of delivery is a crucial component of gene therapy treatment for SMA.
January 18, 2012.
Gene replacement strategies have shown great promise in animal models of SMA. In this current study, the Lorson Laboratory used self-complementary Adeno Associated Virus expressing full-length SMN (scAAV9-SMN) to compare two different routes of viral delivery in a severe SMA mouse model. This was accomplished by injecting scAAV9-SMN vector intravenously (IV) - often referred to as systemic delivery, or intracerebroventricularly (ICV) - direct CNS delivery, into SMA mice.
Both routes of delivery resulted in a significant increase in lifespan and weight compared to untreated mice with a subpopulation of mice surviving more than 200 days. However, the ICV injected mice gained significantly more weight than their IV treated counterparts. Likewise, survival analysis showed that ICV treated mice displayed fewer early deaths than IV treated animals. Also, animals receiving ICV injections also had higher SMN protein levels in the brain and lumbar spinal cord as compared to IV injected animals.
From these results, the authors conclude that the route of injection for scAAV9-SMN has a significant impact upon the degree of rescue and sheds light upon the development of disease and potential therapeutic implications. Intrathecal injections, a safe route for direct CNS delivery in humans, has recently been shown to result in efficient motor neuron transduction when using AAV9, including in a study from the Boulis laboratory using pigs and in a study funded by Families of SMA in the Kaspar laboratory using primates.
Thus, the authors of the Lorson paper conclude that intrathecal delivery may prove to be a desirable route of administration should AAV gene therapy for SMA reach clinical trials ,and; collectively, this study demonstrates that route of delivery is a crucial component of gene therapy treatment for SMA.