Novel PET imaging agent could help guide therapy for brain diseases

Researchers have developed a new imaging agent that could help guide and assess treatments for people with various neurological diseases, including Alzheimer’s, Parkinson’s, and multiple sclerosis. The agent, which is used in positron emission tomography (PET) scans, targets receptors in nerve cells in the brain that are involved in learning and memory. The study is featured in the April issue of The Journal of Nuclear Medicine.

Swiss and German scientists developed the new PET radioligand, 11C-Me-NB1, for imaging GluN1/GluN2B-containing N-methyl-D-aspartate (NMDA) receptors (a class of glutamate receptor) in nerve cells. When NMDA receptors are activated, there is an increase of calcium (Ca2+) in the cells, but Ca2+ levels that are too high can cause cell death. Medications that block NMDA receptors are therefore used for the treatment of a wide range of neurological conditions from depression, neuropathic pain and schizophrenia to ischemic stroke and diseases causing dementia.

“The significance of the work lies in the fact that we have for the first time developed a useful PET radioligand that can be applied to image the GluN2B receptor subunit of the NMDA receptor complex in humans,” explains Simon M. Ametamey, PhD, of the Institute of Pharmaceutical Sciences, ETH Zurich, in Switzerland. “The availability of such a PET radioligand would not only help to better understand the role of NMDA receptors in the pathophysiology of the many brain diseases in which the NMDA receptor is implicated, but it would also help to select appropriate doses of clinically relevant GluN2B receptor candidate drugs. Administering the right dose of the drugs to patients will help minimize side-effects and lead to improvement in the efficacy of the drugs.”

Full story at Science Daily

Experimental imaging agent reveals concussion-linked brain disease in living brain

An experimental positron emission tomography (PET) tracer can effectively diagnose concussion-related brain degeneration while a person is still alive, according to a proof-of-concept study conducted at the Icahn School of Medicine at Mount Sinai and published September 27 in the journal Translational Psychiatry.

Mount Sinai researchers used an experimental imaging agent called [18 F]-T807 (or Avid 1451) with PET to examine the brain of a living, 39-year-old retired National Football League (NFL) player who had experienced 22 concussions and exhibited clinical symptoms consistent with chronic traumatic encephalopathy (CTE), a neurodegenerative brain disease that has been associated with repetitive blows to the head in athletes and soldiers. T807 is designed to latch onto a protein called tau that accumulates in the brain as a result of repetitive traumatic brain injury. When the new imaging agent (or ligand) lights up a PET scan of the brain of a patient showing buildup of tau in a characteristic pattern, the scan result is interpreted as being consistent with CTE. Until now, evidence for CTE pathology has only been possible by examining brain tissue after death.

Full story of PET diagnosing concussion-related brain degeneration at Science Daily