Two-photon fluorescent imaging of myelination in the spinal cord.

Myelination is a fundamental biological process in the vertebrate nervous system. Damage to or malformation of myelin can lead to various neurological diseases; for example, demyelination in the spinal cord is a major cause of paralysis of patients suffering from multiple sclerosis and related diseases. The ability to directly track myelin levels in the spinal cord is needed in order to assess the efficacy of therapeutics in promoting myelin repair. To address this unmet need, 4-((E)-4-((E)-4-aminostyryl)-2,5-dimethoxystyryl)-N-methylaniline, known as Case Imaging Compound (CIC), has been developed as a myelin-targeted fluorescent imaging agent that selectively binds to myelin. CIC was synthesized via an improved route and evaluated as a fluorescent probe for two-photon fluorescent imaging of myelin in the spinal cord in both demyelinated and dysmyelinated models. In vitro and ex vivo tissue staining both suggest that CIC selectively binds to in animal models. Further evaluation in animal models indicated that CIC is sensitive to differences in myelin content in healthy versus pathological myelin. CIC could potentially be useful in the development and evaluation of novel therapies for multiple sclerosis and other demyelinating diseases.