Medical Minutes
Hidden brain benefits found in older adults
A new study for the first time is suggesting that healthy older men and women can generate just as many new brain cells as younger people. There has been controversy over whether adult humans grow new neurons, and some research has previously suggested that the adult brain was hardwired and that adults did not grow new neurons. However, that does not seem to be the case.
A study just published in the journal Cell Stem Cell, suggests that many older adults remain more cognitively and emotionally intact than commonly believed. Lead study author Maura Boldrini, who is an associate professor of neurobiology at Columbia University, said new brain imaging studies are opening up new ways of understanding the brain in older adults.
“We found that older people have similar ability to make thousands of hippocampal new neurons from progenitor cells as younger people do,” said Boldrini. “We also found equivalent volumes of the hippocampus (a brain structure used for emotion and cognition) across ages. Nevertheless, older individuals had less vascularization and maybe less ability of new neurons to make connections.”
The researchers autopsied hippocampi from 28 previously healthy individuals ages 14 to 79 who had died suddenly. This is the first time researchers looked at newly formed neurons and the state of blood vessels within the entire human hippocampus soon after death. The researchers had determined that study subjects were not cognitively impaired and had not suffered from depression or taken antidepressants, which Boldrini and colleagues had previously found could impact the production of new brain cells.
In rodents and primates, the ability to generate new hippocampal cells declines with age. Waning production of neurons and an overall shrinking of the dentate gyrus (part of the hippocampus thought to help form new episodic memories) was believed to occur in aging humans as well.
The researchers from Columbia University and New York State Psychiatric Institute found that even the oldest brains they studied produced new brain cells. Boldrini surmised that reduced cognitive-emotional resilience in old age maybe caused the decline in vascularization, and reduced cell-to-cell connectivity within the hippocampus.
“It is possible that ongoing hippocampal neurogenesis sustains human-specific cognitive function throughout life and that declines may be linked to compromised cognitive-emotional resilience,” said Boldrini.
Higher dairy intake associated with greater bone density in older men
It may be a good idea to make sure you eat your yogurt and cheese, when it comes to bone strength and men over the age of 50. Researchers from Hebrew SeniorLife’s Institute for Aging Research (IFAR) and associates have discovered that higher intake of dairy
foods, such as milk, yogurt and cheese, is associated with higher volumetric bone mineral density and vertebral strength at the spine in men. Dairy intake seems to be most beneficial for men over age 50, and continued to have positive associations irrespective of serum vitamin D status.
In women, researchers found no significant results except for a positive association of cream intake in the cross sectional area of the bone. The study included 1,522 men and 1,104 women from the Framingham Study, ages 32 to 81 years. The researchers, who published their findings in the Journal of Bone and Mineral Density, examined quantitative computed tomography (QCT) measures of bone to determine associations with dairy intake.
Senior study author Shivani Sahni, PhD, who is the Director of the Nutrition Program and Associate Scientist at IFAR, said this is a very carefully structured study that offers significant insights.
“This study related dairy intake with QCT- derived bone measures, which are unique because they provide information on bone geometry and compartment-specific bone density that are key determinants of bone strength,” said Sahni.
Gene therapy may heal brain damage caused by strokes
Gene therapy may help the brain heal from strokes and other injuries. Scientists have found a genetic trigger that may improve the brain’s ability to heal from a range of debilitating conditions, from strokes to concussions and spinal cord injuries.
A new study in mice from UT Southwestern in Dallas, Texas, shows that turning on a gene inside cells called astrocytes results in a smaller scar and potentially a more effective recovery from injury.
“We’ve known that astrocytes can help the brain and spinal cord recover from injury, but we didn’t fully understand the trigger that activates these cells,” said Dr. Mark Goldberg, who is the Chairman of Neurology & Neurotherapeutics at UT Southwestern. “Now we’ll be able to look at whether turning on the switch we identified can help in the healing process.”
The study, published in Cell Reports, found that the LZK gene of astrocytes can be turned on to prompt a recovery response called astrogliosis. Scientists deleted the LZK gene in astrocytes of one group of injured mice, which decreased the cells’ injury response and resulted in a larger wound on the spinal cord. They overexpressed the gene in other injured mice, which stimulated the cells’ injury response and resulted in a smaller scar. Overexpressing the gene in uninjured mice also activated the astrocytes, confirming LZK as a trigger for astrogliosis.
John Schieszer is an award-winning national journalist and radio and podcast broadcaster of The Medical Minute. He can be reached at medicalminutes@gmail.com.com.
John Schieszer is an award-winning national journalist and radio and podcast broadcaster of The Medical Minute.
