While advances in healthcare and medicine have increased life expectancies, the body still declines as it ages, causing a wide variety of problems. Scientists have been trying to learn more about why the aging process seems to be easier on some people, while others experience debilitating diseases, and whether we can ease the process. An answer to those questions might be found by looking at aging on the cellular level, where during aging, the genome becomes unstable, nutrient-sensing pathways degrade, and stem cells become exhausted, among other processes.
Cognitive decline is another known feature of aging, and also occurs to a widely varying degree in different people. The adult brain has to create new neurons on a continuous basis, and for the most part, it happens in only a few parts of the brain. One of those regions is a section of the hippocampus where neural stem cells give rise to new neurons. The maintenance of these cells is critical to memory, and can be influenced by factors like diet and exercise. That may be part of the reason why aging is so heterogeneous.
In this work, the researchers wanted to know more about whether cell pathways that sense nutrients are a link between aging and lifestyle. These pathways are already known to be related to the maintenance of stem cells. Reporting in Communications Biology, scientists learned more about genes that play important roles in sensing nutrients, and how they are related to memory.
This work showed that a gene called ABTB1 is important to the regulation of neural stem cells and may also be related to memory. A gene called GRB10 was suggested to be a molecular link between aging in neural stem cells, diet, and hippocampal-dependent cognitive performance. An interaction between a gene called SIRT1 and exercise levels was linked to memory test outcomes as well.
"Our study shows that nutrient-sensing pathways play an important role in memory and suggests that the ABTB1 and GRB10 genes are likely molecular links for the association between diet, the aging of neural stem cells and our memory ability," said the lead study author, Chiara de Lucia of the Institute of Psychiatry, Psychology & Neuroscience (IoPPN), King's College London. "Identifying these genes as the missing links between these three important variables could inform new approaches to help improve the aging process through targeted changes in diet and exercise and ultimately in developing new drugs in the future."
While people all carry the ABTB1, GRB10, and SIRT1 genes, the sequences for them may carry small differences from person to person, which may modify how people respond to environmental changes.
"Our findings suggest that changes in lifestyle may be able to delay a decline in memory and thinking but that the effectiveness of these approaches will depend on the genetic makeup of each person. For example, adherence to a diet such as the Mediterranean diet may be most beneficial for people with a specific GRB10 mutation while increased exercise may be a better approach for participants with specific SIRT1 variations. Future research should look to replicate these findings on a larger dataset which would allow for the testing of 3-way interactions between diet, exercise and memory to gain a more comprehensive understanding of how these relate to one another," said the senior study author, Sandrine Thuret of the IoPPN.