Only a Matter of Time: Research into Circadian Rrhythms

by YPU Admin on June 9, 2016. Tags: Body Clocks, circadian rhythms, Research, Sleep, and UoM

Introduction


My name is Harriet Van Den Tooren and I’m studying a Masters of Research in Medical Sciences. I started studying medicine in the University of Manchester in 2011 and decided to take a year out to complete a Masters degree in 2015, which was after my fourth year of medicine.

My Masters degree focuses on understanding the changes in bodily functions that occur during the daily cycle, called circadian rhythms, and how they affect the health of the lungs.

In Depth

How does your body know what time it is?

A few things help our bodies to know what time it is, but the most important one is light. Light passes into our eyes, and is converted to an electrical message sent to the brain through the optic nerve. Most of it goes to the back of the brain, which makes sense of the light messages and allows us to understand what our eyes see. Some of it goes to a small part of the middle of the brain called the suprachiasmatic nucleus, which sends messages to the rest of the body using hormones or electrical messages through nerves, which are different depending on whether it is day or night. In most cells of the body, there is a clockwork mechanism that is adjusted by these messages from the suprachiasmatic nucleus, so the whole body is in synchrony. Jet lag occurs because it takes a few days to change re-synchronise the clockwork in all the cells of the body after changing time zones (1).

How does that affect your lungs?

Some diseases are worse at different times of day, such as asthma, which is usually worse during the night. Cells of the lungs and the immune system have the clockwork mechanism too, which help to regulate inflammation of the airways. Usually, cells of the immune system work differently during the day because people are most likely to encounter an infection when they are active, and they reserve energy during the night. It is thought that disruption to the clockwork of cells in the lung and immune system may be a cause of the chronic inflammation seen in asthma. Therefore, understanding how inflammation affects the cellular clockwork, and how the clockwork affects inflammation may help us understand why asthma happens and how we can treat it (1).

One of the hormone signals that synchronises cells clockwork is a steroid humans produce in their body called cortisol, a hormone that also regulates the immune system. There is more of this hormone in the blood during the early hours of the morning and less during the late evening. Doctors treat conditions caused by long-term inflammation, such as asthma, with steroids to reduce inflammation by preventing the immune cells from producing chemicals that cause the inflammation. Research has shown that using steroid treatment during the evening to avoid natural levels falling too low, is more affective that taking it in the morning for asthma. Other medications have been shown to work better when taken at one particular time in the day compared to another time of day (1).

What have I learnt about research in labs this year?

Before I begun this year in September, I was used to learning information from books, memorizing it, and then sitting an exam. Research is completely different to that. Trying to discover new information is a lot harder than learning from books, but it’s also a lot more exciting. I haven’t done much research yet because the first six months has focused on learning lab skills (see my picture of cells when I was learning to stain them) and how to read a scientific paper, but I’ve just started in the labs and I’m definitely looking forward to the next six months! One of the biggest things I’ve learnt is that science is about persistence, you may attempt it many times before you finally get the result you wanted. This applies to experiments but also when applying for funding, jobs and publications. However, if you stick at it and get lucky, you may discover something that makes thousands of lives better.

Going Further

Understanding circadian rhythms can be tough work, but this is a website that has made it easier to understand:

http://thebrain.mcgill.ca/flash/d/d_11/d_11_m/d_11_m_hor/d_11_m_hor.html

Use the buttons on the top left “level of explanation” to start with beginner, and the buttons on the top right “level of organization” to see how circadian rhythms affect molecules, cells and how we think and feel.

If you’re thinking about becoming a doctor, I’d recommend looking at this:

http://www.bma.org.uk/developing-your-career/medical-student/how-to-become-a-doctor. It’s a website that provides information about the qualities needed to be a doctor, what it is like being a medical student and doctor, and how to apply to medicine.

If you’re thinking about becoming a doctor, a great place to start learning about how the body works is here - http://kidshealth.org/kid/index.jsp?tracking=K_Home. Choose your level on the top right “kids” or “teens”

If you like science and you just want to read more, a great place to start is - http://www.bbc.co.uk/science

Similarly - https://publications.nigms.nih.gov/order/pubs_gateway.html has easily understandable news about science, and tips on how to become a scientist.

Papers I read whilst writing this blog:

1.  Durrington HJ, Farrow SN, Loudon AS, Ray DW. The circadian clock and asthma. Thorax. 2014;69(1):90-2.


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