Keeping you up-to-date on recent headlines in neurological science:

Routine stroke prevention therapies are underused in very elderly ... Routine stroke prevention therapies are underused in the very elderly, but could be very effective in this age group. The issues are discussed in a review published in the November edition of The Lancet Neurology. As the average human lifespan increases there are more individuals older than the age of 80 years who have a high quality of life. However, these very elderly individuals are particularly susceptible to stroke. Despite substantial advances in stroke research, with several therapeutic drugs able to enhance clinical outcomes in people with stroke or who are at risk of stroke, the very elderly seem to receive fewer vascular protection interventions that have been shown to be effective in their younger counterparts. Although there has been an under-representation of the very elderly in studies of stroke therapy, these treatments might be of benefit to this group of patients. Indeed, emerging data indicate that the use of several of these therapies in routine clinical practice in the very elderly can be effective. The authors of the study conclude: "With the rapidly growing population of individuals above 80 years, future stroke trials need to include the very elderly to facilitate ready generalizability of results and to convince skeptical clinicians that all patients with stroke should benefit from prompt evidence-based treatment, regardless of age."

Cholesterol important for brain development ... A new study by an international team of researchers found that cholesterol is important for the formation of brain cells, and they hope the findings will help scientists cultivate dopamine-producing cells outside the body. The study is published in the October 2 issue of the journal Cell Stem Cell. One of the many challenges of using stem cells in medicine and research is how to control them so cell growth and proliferation does not get out of hand. Stem cell therapies have great potential as treatments for brain-wasting diseases such as Parkinson's disease, where motor function diminishes in line with decline in specialist brain cells that make the neurochemical dopamine which is essential for many brain processes, including motor skills and reward systems. This study used mice to show that to function properly; dopamine-producing brain cells depend on a chemical called oxysterol being able to activate a specific receptor. Oxysterol is an oxidized form of cholesterol. The researchers also found that treating lab-cultivated embryonic stem cells with oxysterol helped them make more dopamine-producing cells and reduced uncontrolled growth of the stem cells. "Oxysterol contributes to a safer and better cultivation of dopamine-producing cells, which is a great advancement since it increases the possibility of developing new treatments for Parkinson's disease," said lead investigator Ernest Arenas, MD, of the Center for Developmental Biology and Regenerative Medicine at Karolinska Institute (Stockholm, Sweden).

Weight loss surgery could benefit carpal tunnel sufferers ... As bariatric surgical procedures (BSPs), or weight loss surgeries, have become increasingly common, so have their associated neurological complications. However, for patients with a pre-surgical diagnosis of carpal tunnel syndrome (CTS), the benefits of the bariatric surgery may actually help improve the painful symptoms of CTS. CTS is caused by the compression of the median nerve through the carpal tunnel in the wrist area. When constricted, blood cannot flow freely through the hand to the fingers causing individuals with CTS to experience numbness and pain in the hand. A recent study took place to evaluate the effects of bariatric surgery in patients with a pre-surgical diagnosis of CTS. In 14 of the study patients, a significant and progressive improvement in clinical and neurophysiological evaluation performed after BSP was observed. The improvement on the outcome of CTS after BSP can be related to a decrease of fatty tissue in the carpal tunnel or may be due to a reduction of the hydrostatic pressure through it. The complete findings were presented at the recent American Association of Neuromuscular & Electrodiagnostic Medicine (Rochester, Minnesota) 56th Annual Meeting in San Diego.

Physical activity in adolescence could decrease risk of brain cancer... While little is known about the causes of glioma, researchers at the National Cancer Institute (NCI; Rockville, Maryland) have found that this rare but often deadly form of brain cancer may be linked to early life physical activity and height. "Our findings suggest that biological factors related to energy expenditure and growth during childhood may play a role in glioma etiology. This clue could help researchers better understand important features of glioma biology and the potentially modifiable lifestyle factors that could be important in preventing this disease," said Steven Moore, PhD, research fellow in the Nutritional Epidemiology Branch, NCI. Moore also added that "engaging in regular physical activity throughout the lifespan conveys many benefits." Results of this prospective study are published online in the journal Cancer Research. Gliomas are the most common type of brain cancer, accounting for nearly 80% of brain and central nervous system cancers. Though little is known about the causes of glioma, some evidence suggests that early life exposures may play a role in disease etiology. Because the brain develops rapidly during childhood and adolescence, it may be more susceptible to environmental influences during this time. Participants who were physically active during adolescence had a decreased risk of glioma; their risk was about 36% lower than those who were inactive, according to the study. The researchers also found that those who were obese during adolescence had an increased risk of glioma; their risk was approximately three to four times that of individuals who were normal weight during adolescence.

Study pinpoints gene controlling numbers of brain cells ... In populating the growing brain, neural stem cells must strike a delicate balance between two key processes – proliferation, in which the cells multiply to provide plenty of starting materials – and differentiation, in which those materials evolve into functioning neurons. If the stem cells proliferate too much, they could grow out of control and produce a tumor. If they proliferate too little, there may not be enough cells to become the billions of neurons of the brain. Researchers at the University of North Carolina at Chapel Hill School of Medicine have now found that this critical balance rests in large part on a single gene, called GSK-3. The finding suggests that GSK-3 controls the signals that determine how many neurons actually end up composing the brain. It also has important implications for patients with neuropsychiatric illness, as links have recently been drawn between GSK-3 and schizophrenia, depression and bipolar disorder. In a study appearing online in the journal Nature Neuroscience, William Snider, MD, and colleagues created a mouse model in which both forms of the GSK-3 gene – designated alpha and beta – had been deleted. They decided to go after GSK-3 – which stands for glycogen synthase kinase 3 – because it is one of the most studied kinases or signaling molecules in all of biology. The researchers used a "conditional knock-out" strategy to remove GSK-3 at a specific time in the development of the mouse embryo, when a type of cell called a radial progenitor cell had just been formed. As the brain develops, neural stem cells evolve through three different stages – neural epithelial cells, radial progenitor cells and intermediate neural precursors. The radial progenitor cells are especially important because they are thought to provide the majority of the neurons of the developing brain but also differentiate themselves to give rise to all the cellular elements of the brain. The researchers discovered that deleting GSK-3 during this second phase of development caused the radial progenitor cells to be locked in a constant state of proliferation.

— Compiled by Rob Kimball, MDD