Those of us who support holistic solutions to health problems are never surprised by the interconnections between “unrelated” parts of the body.
Perhaps the most striking example in recent years has been the discovery of the gut-brain axis and the influence of the colon on brain health.
But I have to admit even I was surprised by recent research suggesting that the bones may hold the key to understanding Alzheimer’s.
This is what the new study revealed.
Gene Research is Going Nowhere
The research team, which was drawn from the Northeast Ohio Medical University (NEOMED) in Rootstown, published their findings in the Journal of Alzheimer’s Disease.
The background for their work is that genes are the clear culprit in only one out of 20 cases of Alzheimer’s. So (as I’ve often said) focusing on genetic causes will be a waste of time for the vast majority of victims.
The priority should be to identify new risk factors and biomarkers and use those as a lever to encourage people to take preventative steps to avoid the disease.
The NEOMED team believe they have come up with such a factor.
The Serotonin Connection
It all started with a hunch that bone loss could be one of the earliest indicators of brain degeneration in Alzheimer’s disease.
In some cases of Alzheimer’s disease, researchers are seeing early reductions in bone mineral density (BMD) in an area of the brainstem that produces most of the brain’s serotonin. Serotonin is a well-known neurotransmitter that controls mood and sleep.
And, as readers of this newsletter know, disturbances in mood and sleep are familiar symptoms of Alzheimer’s disease.
The Ohio team observed, “Reduced bone mineral density (BMD) and its clinical sequelae, osteoporosis, occur at a much greater rate in patients with Alzheimer’s disease (AD), often emerging early in the disease before significant cognitive decline is seen.”
They investigated the idea by using “htau mice.” These mice have been genetically engineered to develop human forms of abnormal tau proteins that become faulty in Alzheimer’s, and disrupt key cell structures called microtubules.
Before the mice developed any significant tau abnormalities, their bone mineral density (BMD) was measured. Compared to normal mice, the htau mice had significantly reduced BMD, particularly in the males.
More detailed examination revealed important cellular changes in a region of the brainstem called the dorsal raphe nucleus (DRN). The authors described this as “a pivotal structure in the regulation of the adult skeleton.” It’s also the area that produces the majority of brain serotonin.
This is the first report of bone degeneration in this area that associates it with Alzheimer’s.
Assess Alzheimer’s Risk with a Simple Bone Test
One of the authors, Dr Christine Dengler-Crish said, “Measurement of bone density, which is routinely performed in the clinic, could serve as a useful biomarker for assessing Alzheimer’s Disease risk in our aging population.
“The findings of this study motivate us to explore the serotonin system as a potential new therapeutic target for this devastating disease.”
Her colleague Dr. Jason Richardson, director for Neurodegenerative Disease and Aging Research at NEOMED, added, “This is extremely exciting and has significant translational potential and relevance to early detection of the disease.”
In osteoporosis the focus is usually on the risk of fractures, which are often the beginning of the end when they occur in elderly people. As far as I know, it’s a new idea that bone deterioration, in an overlooked area that produces an important neurotransmitter, may be a mechanism that brings on Alzheimer’s or makes it worse.
At present we don’t know whether bone loss causes dementia or vice versa; for now we know the two often happen side by side, and people with BMD loss are probably at greater risk of failing memory.