Interested, aren’t you? Us, too. Anything to help get a better night’s sleep!
There is a bit of technical information here, so give us a chance to explain – and let us know if you have any unanswered questions – we always do!
Every human being’s internal clock (also known as the sleep-wake cycle) is controlled by a group of genes called clock genes.
These genes vary their activity throughout the day. They can form an ‘established’ pattern if you have a strict and consistent sleep-wake schedule, (does anyone really have this?) which drives our circadian rhythms (the 24-hour cycle).
The first clock genes were not identified until 1997, and since then, researchers have been looking for reliable ways to isolate and study the clock genes, in order to better understand the sleep-wake cycle of the human being. (This was also tested in mice.)
Why Are Clock Genes Important?
Disruption of the natural circadian rhythm can cause a bunch of health problems, including permanent jet lag, insomnia issues, and increased risk of heart diseases and stroke.
To be able to analyze the clock gene would be able to accurately treat and even prevent some of these sleep-related disorders and issues.
Initially two methods had been developed to try to isolate the clock genes, but both have proven to be unreliable, so researchers have been looking for a new method.[i]
Check Your Hairbrush
In very recent news, scientists have finally found a reliable way to isolate the clock gene, using human hair.
Apparently, if you tweeze or pluck a human hair from the scalp, the hair follicle cells that stay attached to the root are excellent samples of RNA:
“Total RNA purified from scalp hair follicle cells exhibits clearly distinguishable peaks correlating the 18S- and 28S-rRNA signals, suggesting these cells are suitable for isolation of high-quality total RNA.”(1)
Upon closer examination, the researchers isolated three clock genes that were easily readable within the hair follicle cells.
The three eligible genes are the PER3, NR1D1, and NR1D2, the only three of seven total[ii] clock genes that were found to have reliable enough markers to chart the human sleep cycle.
Only these three “met the criteria for rhythm markers of the circadian clock.”(2)
First Experiment – To Establish The Control
To make sure the hair follicle test would prove to be accurate time and time again, researchers performed a control experiment to test their initial hypothesis and ideas.
The idea was to establish a basic circadian rhythm that could be found successful in hair, with tests that could be successfully repeated.
To do this, four healthy individuals were put on a very strict eating, sleeping, and waking schedule, which acted as the “period of maintenance” to establish a set circadian pattern that would be seen in the hair, and then the testing began.
The individuals were monitored for three weeks, with hair samples being taken every four hours.[iii]
On average, it took only 10 hairs from each person to get a great sample of clock genes with accurate and consistent results. For people with thin hair, 20 strands were taken, while only 5 were taken from people with thick hair.
This is cool, too – beard hair (from men…) was also sampled, and it took only about 3 hairs to get accurate results from the facial hair cells.
In all the hair follicles of all four individuals, the circadian levels fluctuated as expected with the sleeping, eating, and waking schedule set by the researchers.
This proved that the hair follicle’s cells, with the three isolated clock genes, were a reliable way to monitor the “human peripheral circadian clock.”(3)
Over another three weeks, the scientists forced a shift in the four individual’s schedules, advancing their schedules by 4 hours over the course of three weeks.
Though the schedules had been advanced by 4 full hours, hair samples taken at the end of the three weeks revealed only a change in the cells by 2.1 hours on average.
This proves two things. First, it reiterates that hair follicle cells provide good examples of the sleep-wake cycle, and it also shows that three weeks was not enough time for the body to ‘catch-up’ and adjust to the new schedule.
The body’s internal clock simply did not match the new schedule. This puts the individual at increased risk for circadian rhythm-related disorders, like insomnia, stroke, and some heart conditions.
A second experiment was conducted as well. A group of six individuals with a schedule of rotating shifts were followed – the people worked one week from 6am-3pm, and the next week from 3pm-12am, rotating back and forth.
This group was followed for a full three weeks as well, and the researchers determined that these people stayed in a perpetual state of jet lag.
According to their clock genes, the worker’s bodies never ‘caught up’ with their new schedules. Risk of on the job errors, insomnia issues, heart and stroke issues rises considerably with this group, according to the experiments.
As with most of our articles, the conclusion here is not the results we have found so far, but the new avenues of research that can now be conducted.
It would be really interesting to follow a group of individuals until the body did ‘catch up’ with the forced shift schedule, with the evidence of the sleep-wake cycle captured by the hair test.
I wonder how long it would take the body to catch up to the 4 hour shift mentioned above – the experiment only went on for three weeks.
It will also be cool to see how scientists end up applying this new information, and what ills it can help to cure or prevent. Since this is brand new information, the possibilities are endless.
[i] The other methods tried were isolating the genes from white blood cells and mouth cells. Collecting white blood cells was invasive, costly, and the time delay from collecting to processing the cells made their readings inaccurate. Collecting tissue from the mouth to harvest RNA there has also proved unreliable because the researchers claim the samples are often fragmented, incomplete, and do not give accurate readings either. A new method was necessary to continue the research.
[ii] The others, PER2, Dbr, Bmal1, and Npas2, are not usable because they do not contain enough circadian properties to help detect nuances in the human sleep-cycle analysis.
[iii] Behavioral rhythms were monitored using a device called the Actiwatch, which measured circadian rhythms.
Source: Akshi, Makoto, et al. “Noninvasive Method for Assessing the Human Circadian Clock Using Hair Follicle Cells.” Proceedings of the National Academy of Sciences. August 24, 2010.