Memory loss is one of the hallmarks of Alzheimer's disease.
But it may be possible to reverse the symptom, restoring
people's memories, according to researchers.
people's memories, according to researchers.
Research published in the journal Brain suggests that a
new approach using epigenetics – the study of chemical
reactions and factors that influence genetics without
changing the DNA sequence, effectively switching genes on
and off, had shown it was possible to reverse memory decline.
new approach using epigenetics – the study of chemical
reactions and factors that influence genetics without
changing the DNA sequence, effectively switching genes on
and off, had shown it was possible to reverse memory decline.
Scientists used mouse models carrying the gene mutations for
familial Alzheimer's, where more than one member of a family
had the disease, as well as post-mortem brain tissue from
Alzheimer's patients.
familial Alzheimer's, where more than one member of a family
had the disease, as well as post-mortem brain tissue from
Alzheimer's patients.
She said a key reason for cognitive decline in Alzheimer's
patients is the loss of glutamate receptors, which are critical
to learning and short-term memory – itself the result of an
epigenetic process known as repressive histone modification.
patients is the loss of glutamate receptors, which are critical
to learning and short-term memory – itself the result of an
epigenetic process known as repressive histone modification.
Scientists used epigenetics to try to reverse the effects of memory loss in Alzeimer's patients (Picture: Getty)
She said: "We found that in Alzheimer's disease, many
subunits of glutamate receptors in the frontal cortex
are downregulated, disrupting the excitatory signals,
which impairs working memory."
subunits of glutamate receptors in the frontal cortex
are downregulated, disrupting the excitatory signals,
which impairs working memory."
By understanding that process, scientists could identify
potential drugs that would reverse the process.
potential drugs that would reverse the process.
"Our study not only reveals the correlation between
epigenetic changes and Alzheimer's, we also found we
can correct the cognitive dysfunction by targeting the
epigenetic enzymes to restore glutamate receptors," said
Prof Yan.
epigenetic changes and Alzheimer's, we also found we
can correct the cognitive dysfunction by targeting the
epigenetic enzymes to restore glutamate receptors," said
Prof Yan.
"In this paper, we have not only identified the epigenetic
factors that contribute to the memory loss, we also found
ways to temporarily reverse them in an animal model of
Alzheimer's Disease."
factors that contribute to the memory loss, we also found
ways to temporarily reverse them in an animal model of
Alzheimer's Disease."
Researchers injected the Alzheimer's animals three times
with compounds designed to inhibit the enzyme that controls
repressive histone modification.
with compounds designed to inhibit the enzyme that controls
repressive histone modification.
Prof Yan said: "When we gave the Alzheimer's animals this
enzyme inhibitor, we saw the rescue of cognitive
function confirmed through evaluations of recognition
memory, spatial memory and working memory.
enzyme inhibitor, we saw the rescue of cognitive
function confirmed through evaluations of recognition
memory, spatial memory and working memory.
"We were quite surprised to see such dramatic cognitive
improvement. At the same time, we saw the recovery of
glutamate receptor expression and function in the frontal
cortex."
improvement. At the same time, we saw the recovery of
glutamate receptor expression and function in the frontal
cortex."
Future studies will be needed for long-lasting results,
Prof Yan said, but she said an epigenetic approach
works well for brain disorders such as Alzheimer's
because they allow the control of many genes rather
than just one.
Prof Yan said, but she said an epigenetic approach
works well for brain disorders such as Alzheimer's
because they allow the control of many genes rather
than just one.
She added: "An epigenetic approach can correct a
network of genes, which will collectively restore cells
to their normal state and restore the complex brain function."
network of genes, which will collectively restore cells
to their normal state and restore the complex brain function."
