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

Underuse of anti-clotting therapies common among patients with atrial fibrillation who have a stroke

Inadequate use of anticoagulation therapies was prevalent among patients with atrial fibrillation who experienced a stroke, according to a study appearing in the March 14 issue of JAMA.

Atrial fibrillation (AF) is an independent risk factor for stroke, increases stroke risk by a factor of 4 to 5, and accounts for 10 percent to 15 percent of all ischemic strokes. While the burden of AF-related stroke is high, AF is a potentially treatable risk factor. Numerous studies have demonstrated that vitamin K antagonists, such as warfarin, or non-vitamin K antagonist oral anticoagulants (NOACs), reduce the risk of ischemic stroke. Based on these data, current guidelines recommend adjusted-dose warfarin or NOACs over aspirin for stroke prevention in high-risk patients with AF.

Full story of anti-clotting therapies for AF at Science Daily

Excess weight in women has different effects on different types of stroke

According to new research, women who are overweight or obese may have an increased risk of the most common kind of stroke, called ischemic stroke, but a decreased risk of a more often deadly stroke, called hemorrhagic stroke. The study is published in the September 7, 2016, online issue of Neurology®, the medical journal of the American Academy of Neurology.

Stroke is a leading cause of death and disability worldwide and the fifth leading cause of death in the United States.

“We found that the risk of ischemic stroke, which is associated with a blockage of blood flow to the brain and is the most common stroke subtype, is increased in overweight and obese women. By contrast, the risk of hemorrhagic stroke, which is associated with bleeding into the brain, is decreased in overweight and obese women,” said study author Gillian Reeves, PhD, with the University of Oxford, United Kingdom. “Our findings add to the growing body of evidence that different types of stroke have different risk profiles.”

Full story of excess weight in women and strokes at Science Daily

Researchers study differences in ischemic stroke in marijuana users

A new study found strokes in young adults who use marijuana are more likely to be caused by stenosis, narrowing of the arteries, in the skull than strokes in non-users.

Previous studies have found an association between marijuana use and stroke, but the new study published as a research letter in the Nov. 3 issue of the Journal of the American College of Cardiology is the first to explore differences in stroke in marijuana users and non-users, an approach that can help researchers begin to identify possible mechanisms for stroke in users.

The researchers from The University Hospital of Strasbourg in Strasbourg, France, looked at all patients under age 45 admitted with ischemic stroke from 2005 to 2014, creating a study cohort of 334 patients, including 58 who were marijuana users. Ischemic stroke is caused by a blockage that interrupts or reduces blood flow to the brain as opposed to hemorrhagic stroke, which occurs when a blood vessel in the brain leaks or ruptures.

Full story of ischemic stroke in marijuana users at Science Daily