The Exercise Pill

Enhancing a liver protein mimics the benefits of exercise on the brain.

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By Yume Igarashi

Imagine a pill that, when consumed, mimics the metabolic effects of exercise on the brain: brain tissue receives more oxygen due to an increased heart rate, which then promotes brain plasticity (the neurological ability of the brain to change, grow, and adapt). Exercise can even stimulate the growth and development of new brain cells, which can lead to improvements in memory and cognitive function. By simply ingesting this intriguing “exercise pill,” one could cease to engage in physical activity altogether. More importantly, however, consolidating the brain benefits of exercise into a drug available to older adults could play a significant role in combating age-related cognitive declines by protecting the brain directly through the simulation of daily exercise.

The contents of such a pill were researched thoroughly during multiple experiments on mice of varying ages and levels of vitality. In a study featured in “Science Magazine,” researchers took the blood plasma from healthy, active mice and injected it into older, lethargic mice. The results were astounding: the older mice showed signs of increased brain activity similar to the effects present after the active mice did exercise. The mice that received the injection experienced increased levels of fitness and memory retention and even new neuronal growth in the hippocampus. It was almost as if some mystery molecule in the plasma of the healthy mice magically rejuvenated the older mice by tricking their brain into thinking they had just exercised.

These results support a theory endorsed by several scientists regarding the presence of a liver protein in blood plasma called GPLD1. GPLD1 is an enzyme that targets cells by releasing proteins on their surface to complete biological jobs usually associated with metabolism. In fact, this liver enzyme circulates in the blood soon after exercise but lacks prevalence in the blood of inactive elders (older people tend to exercise less frequently and thus have less GPLD1 circulating in their blood). As a result, it would make sense that proteins within the plasma of healthy mice were able to target cells in the sedentary mice and mimic the brain benefits of exercise.

According to another study conducted by the University of California—San Francisco (UCSF), GPLD1 could potentially provide a key to understanding age-related cognitive declines and neurodegenerative disorders, as daily exercise is often unavailable to older adults due to physical limitations or disabilities. It was these researchers at UCSF who believe that the production of an “exercise pill” (including GPLD1 in its contents) which imitates the benefits of exercise on the brain will be available for consumption soon.

In a broader scope, these observations of liver-to-brain communication emphasize the startling levels of interconnectedness our organs possess. By attempting to understand the various processes GPLD1 undergoes, a therapeutic breakthrough is on the horizon. The fact that a singular protein produced in the liver can generate astonishing effects on the overall health of the brain has inspired scientists to search for ways to seamlessly connect the two organs in future developments.