Losing Sleep Over It: Researching the Link Between Alzheimer's and Circadian Disruption
A pharmacology and neuroscience student at SIU School of Medicine, Jesse Britz, along with Shelley Tischkau, PhD, and the Smith Alzheimer's Center Hascup Labs, recently researched the link between Alzheimer's and circadian rhythm (the body's 24-hour internal clock). Britz, who is from Divernon, earned his PhD this past December.
Tell us about your recent research.
The whole focus of the project started because sleep/wake cycles are heavily disrupted in Alzheimer’s. For a long time it’s been looked at as a symptom – sundowning is a term that is normally used.
People in late-stage Alzheimer’s disease will get up in the middle of the night, sometimes get aggressive, agitated. Their sleep patterns are all messed up. For a long time, that’s been known, but some other groups have looked at disruptions playing a role before Alzheimer’s is diagnosed. We wanted to see how these two potentially play into one another.
Why did you look at the difference between males and females?
Females are two-thirds more likely to develop Alzheimer’s disease, so there’s definitely something going on there. From a circadian standpoint, we found sex differences that had never really been seen before. Actually, there’s really only been a push in the last couple of years to use female animals in studies. Previously, they used all males.
But from the start, we were going to compare the two.
How was the project designed?
The whole project is designed to simulate a chronic jetlag condition. The easiest way to describe it is if I worked night shift five days of the week and tried to rebound to an 8-to-5 schedule on the weekends, then go back to night shift. That’s the easiest way to think about our lighting paradigm. And we wanted that to be chronic because someone who works night shift does it for 25 years. Small interruptions are not going to cause a drastic effect.
The irony is, you have to collect these samples at all different times of the day. I spent a lot of time at 2 a.m. and 4 a.m. in the lab to make sure we had consistent data.
What did you find?
In short, the major finding from this entire project is that our male Alzheimer’s animals were highly susceptible to the effects of chronic circadian disruption and it exacerbated the Alzheimer’s phenotype, whereas the females seemed more protected from it.
The circadian system has been linked to so many more things than Alzheimer’s – cancer, metabolic syndrome (which can lead to heart disease, stroke and diabetes). I think the takeaway point is that the circadian system is fragile and chronic disruption is going to have an effect on your health.
Want to read the full manuscript? Dive into the research here.