Home › Blog › Your Cells and Organs Have a Biologic Clock: Be Nice to Your Stem Cells

Because of our high-tech, rapid-pace lifestyles, it’s easy for the circadian rhythms of American’s today to get out of whack. And, it’s not just jet lag. Disruption in these cycles can lead to premature aging, depression, allergies, and even, cancer.

What is a Circadian Rhythm?

Circadian rhythms, found in almost all living things, are physical, behavioral, and mental changes that follow a 24-hour cycle. They are produced and regulated by biological clocks, which scientists have discovered exist in nearly every organ and tissue of the body. The proteins that make up biological clocks interact with individual cells throughout the body.

The master clock, the one responsible for keeping all of the other biological clocks in the body in sync, is located in the brain (in the hypothalamus). This “grandfather” of all clocks receives direct input from the eyes.

The Eye is the Window to the Clock

While factors within your own body produce circadian rhythms, input from outside the body also affects them. The main influencer of circadian rhythms is daylight, which can essentially slow down, speed up or completely reset biological clocks. This makes sense when you remember that the master clock receives direct input from the eyes.

Probably the best-known light-related circadian rhythm is being awake during the daytime and sleeping during the night. Other clock-controlled bodily functions that fluctuate with the time of day include:

• Blood circulation and blood pressure
• Urine production
• Body temperature
• Hormone secretion
• Metabolism

Even the rate of hair growth is governed by circadian rhythms!

Chronobiology: The Study of Bodily Rhythms  

To add to what we currently know about circadian rhythms, researchers at the University of California, Irvine last week published the results of their study that shows that biological clocks found in other various organs and tissues of the body can operate independently of the “master clock” located in the brain.

For their study, the chronobiologists shut down the entire circadian circuit, including the master clock, of the mice they were studying. They then isolated and re-booted only the clocks of the liver or the skin. Amazingly, despite the absence of all the other clocks, the liver sensed the time and went about its vital tasks as day turned to evening. The liver’s clock only stopped working when the mice were subjected to constant, total darkness.

This Biological Clock is Also in Your Stem Cells

In a recent study, researchers looked at the biologic clocks in mesenchymal stem cells. What did they find? That clock restrains inflammation in a model of inflammatory arthritis. Meaning the stem cells in joints have a need for a regular clock like the rest of your body and when you mess with that clock, more inflammation ensures.

The upshot? The cells in your body know if it’s day or night even if you don’t. The big take-home here for your health and stem cell procedure is that getting into a circadian rhythm that’s regular will reduce the stress on your body and stem cells. This means going to bed most nights at the same time, waking up at close to the same time, and letting your body follow the increasing daylight the summer has to offer. Your stem cells will thank you! 

Chris Centeno, MD is a specialist in regenerative medicine and the new field of Interventional Orthopedics. Centeno pioneered orthopedic stem cell procedures in 2005 and is responsible for a large amount of the published research on stem cell use for orthopedic applications. View Profile