Hypoxia may build multigenerational resilience against dementia

An intriguing new study finds that, in mice, repetitive exposure to hypoxia may protect against dementia. Manu Prats/Stocksy

Vascular dementia is the secondTrusted Source leading cause of dementia following Alzheimer’s. It occurs due to the interruption of blood and oxygen supply to the brain, which damages the blood vessels.

Low oxygen levels elsewhere in the body can also disrupt other critical organs and their functions. For instance, reduced blood supply to the heart can lead to cardiovascular disease and heart attacks.

Because low oxygen levels in the body can cause life threatening conditions, it seems paradoxical to deprive a tissue or organ of oxygen to confer benefits. However, a group of researchers is examining some potential benefits of exposure to low oxygen levels, also known as hypoxia.

The scientists recently carried out a study to address two hypotheses:

That hypoxia will reduce the deficits in a mouse model of vascular cognitive impairment and dementia.
That succeeding generations will inherit this “dementia-resilient phenotype.”
The results of the study appear in Alzheimer’s & Dementia: The Journal of the Alzheimer’s AssociationTrusted Source.

Epigenetics explored
Although the genetic code we are born with remains constant throughout our lives, the way in which this code can be read, or translated, can change. This is called epigenetics. Our environment and behaviors can influence not what the DNA code “says,” but whether or not a gene is turned “on” or “off.”

For instance, methylationTrusted Source is one form of epigenetic change. Certain behaviors may cause sections of DNA to become methylated, meaning a methyl group is added to the DNA.

Once a gene is methylated, it is less likely to be expressed. So, although the gene is still present and functional, it is effectively switched off or dialed down.

Importantly, these epigenetic changes can pass from generation to generation without altering the genetic code.

In the current study, scientists put the experimental animals through repetitive hypoxic conditioning (RHC)Trusted Source. The animals in the RHC condition experienced low levels of oxygen — similar to being at a high altitude — for 1 hour every other day over a 2-month period.

After this conditioning, the researchers subjected the mice to chronic cerebral hypoperfusion, which induces vascular dementia.

They assessed changes in memory and other brain functions 3 and 4 months later, respectively.

The research revealed that induced memory and brain function deficits caused by chronic cerebral hypoperfusion were reversed in the animals that had experienced RHC.

Similarly, the offspring of RHC-treated parents also showed strong resilience to dementia without experiencing RHC.

The authors write: “[N]either mice treated directly with 2 months of RHC or their adult offspring showed changes in white matter myelin density, neurocognitive function, or synaptic plasticity.”

Please follow and like us: