The hypothalamus, known as the part of the brain that coordinates the autonomic nervous system and secreting hormones, regulates important processes like growth and metabolism. However in 2013, scientists discovered that the hypothalamus is also responsible for the causation of systemic ageing. But, how? Today, scientists have answered the question through a study done on mid-aged mice.
The mice model
Dr Dongsheng Cai and his team have identified the adult neural stem cells in the hypothalamus which control ageing. These stem cells generate new brain neurons and replace those that die off. Cai and his fellow colleagues monitored these cells in a group of mice as they aged. Typically, mice live up to two years – and through their observation, it was noticed that the stem cells began dying off mid-age at 11 months. Consecutively, the mice also lost muscle endurance, sociability and memory – essentially undergoing the process of ageing.
The team then began to engineer a kill on the hypothalamic stem cells when the mice were only 15 months old. Thereafter, the mice displayed signs of ageing – before dying prematurely at 200 days. Likewise, when newborn mice stem cells were implanted into the middle-aged mice, they gained vigour, performed better and lived 200 days more than they would have.
To further consolidate the findings, Cai’s team studied the fluids around the stem cells. The fluids were loaded with packets of RNA called exosomes. These exosomes were isolated and injected into two groups of mice: middle-aged mice with damaged hypothalamic stem cells and normal middle-aged mice. Both groups of mice significantly improved in performance and endurance after the implantation, concluding that there was something profound in these RNAs that slowed down ageing.
What does this mean for humans?
The process of ageing is highly researched, so that interventions that can improve human lives later on can be introduced. Ideally, humans can grow old without being acquainted with age-related diseases such as dementia. This study is interesting and possibly breakthrough-quality if the same mechanisms derived from the mice can be implemented on humans.
With the mice model, there were many disclaimers. For one, only male mice were used in the study and it is a known fact that there are distinct differences in the hypothalamic structures of the two sexes. It is also unclear if the exosomes could be passed through the barrier in the brain that protects itself from infections. In the study with mice, the stem cells had been engineered to make them resistant to inflammation, which caused cessation of the cells. Ultimately, it is a matter of translating this knowledge and applying them to human beings.
Presently, Cai and his team are determining which of the RNAs secreted by the hypothalamic stem cells are most potent in its anti-ageing effects. This is perhaps the first step in slowing down the ageing process and combatting age-related diseases.
“During the next few years, we still want to understand the whole picture as completely as we can,” said Cai. “Then we can more seriously get to the therapeutic stage,” he added. MIMS
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