Can sleep deficiency really kill you?

As I have stated before I am one of the unfortunate 64 million people in America that suffer from insomnia. My dad has it, my brother has it, and I have it. Without insomnia I probably wouldn’t get a whole lot of things done (like this blog post). Fortunately for me having insomnia also has some other perks, such as getting to watch TV shows about insomnia. Earlier tonight I watched a show on the National Geographic channel about a form of insomnia that I was completely unaware of and I am sure I am not the only person who is unaware of it since it affects only 40 families in the entire world. This type of insomnia is called Fatal Familial Insomnia or FFI. I never thought that Insomnia could kill someone, but this form of Insomnia makes every person who is diagnosed with it a victim.

I thought that I would go over the sleep cycle a little bit first to help you understand how sleeping works but since a colleague has already posted a blog about it I will just set up a link to that post here http://fourthirstypandas.blogspot.com/2010/04/sweet-dream-or-beautiful-nightmare.html.

FFI has been characterized as a genetic disorder caused by a mutation at codon 178 of the prion protein gene. This is also a problem in the condition called “Mad Cow Disease.” Prions are proteins that attack the nervous system and cause the symptoms associated with “Mad Cow Disease.” In FFI the cause of the prion protein is genetic, where a single base pair is coded incorrectly. This is one of 3 billion base pairs known in the human genome. In FFI the prions accumulate in the Thalamus in the brain. The Thalamus was never thought to control sleep, but it does transmit signals to the cortex of the brain. In patients with FFI lesions occurred in the Thalamus and the Cortex of the brain. With FFI 90% of the neurons in the Thalamus have disappeared.

ally sleep has been one of the hardest things to study, but some recent studies using a PET scan and a tagged amino acid may give us some clues as to why we need to sleep. One of the theories is that we need sleep to repair proteins in the cells of the brain, which can’t happen while we are awake because the brain is too busy and has too many processes happening. During a normal day while we are awake we accumulate adenosine in our brain, which signals our bodies to sleep. Sleep would eliminate the adenosine and produce more proteins for repair of the brain cells.

Humans have varying levels of sleep, but so do many animals in nature. A normal human gets somewhere between 7 and 8 hours of sleep per night, but an animal such as a lion gets up to 15 hours a day. A elephant on the other hand gets around 4 hours of sleep. One of the theories about this is that predator species can sleep more because they don’t generally have many predators, while the prey species get much less sleep so they can evade their predators. But what if we could sleep and be awake at the same time. I know this sound ridiculous, but a few animals in nature already have achieved this process. If we could somehow find out how to translate this to humans we could eliminate FFI and other sleep associated disorders.

One of the species in nature that sleeps all the time but we never see it are dolphins. I always think of a dolphin as an animal that is always moving and swimming. A study done in San Diego evaluated if a dolphin lost any mental abilities when forced to stay alert for multiple days. The dolphin was trained to detect a swimmer that was in the bay while the dolphin was detained in a fenced area. When the dolphin detected the swimmer it hit a switch on the dock. The dolphin showed no decline in activity and detected every time the swimmer was in the bay. The dolphin slept throughout the entire experiment. This is possible due to dolphins having something called unihemispheric sleep. Throughout the dolphins life one half of their brain is active while the other is sleeping and then they switch. Another animal that is theorized to do this is many different avian species. Studies have shown that they can sleep while also watching for predators while they are on land, but it is still unclear wheather they can sleep while flying.

So far for all terrestrial mammals, sleep is needed. After several days of sleep deprivation there is a drastic decrease in overall health. One side effect is diabetes, due to insulin resistance that is accumulated. There is also a decrease in lymphocytes which fight bacterial infections in the body. In most mammals if sleep is deprived for 2 weeks death will occur. In patients with FFI death usually occurs from 7 to 36 months, and the unfortunate thing is that once symptoms of FFI start they never go away until the patient dies. The unfortunate thing about this disease is that there is currently no cure. And if one family member is ever diagnosed with FFI there is a 50% chance that their children will be diagnosed with it as well since it is a dominant gene.

So now that I have accumulated a massive amount of adenosine in my brain I think I will go sleep and I encourage everybody else to get sufficient amounts of sleep as well.

References:

1. National Geographic Explorer: “Fatal Insomnia”, aired April 27, 2010

2. Fatal familial insomnia: clinical features and molecular genetics; PIETRO CORTELLI, PIERLUIGI GAMBETTI, PASQUALE MONTAGNA and ELIO LUGARESI; J. Sleep Res. (1999) 8, Suppl. 1, 23-29; European Sleep Research Society

3. Montagna P, Gambetti P, Cortelli P, Lugaresi E (2003). "Familial and sporadic fatal insomnia". Lancet Neurol 2 (3): 167–76. doi:10.1016/S1474-4422(03)00323-5

4. Almer G, Hainfellner JA, Brücke T, et al. (1999). "Fatal familial insomnia: a new Austrian family". Brain 122 ( Pt 1): 5–16. doi:10.1093/brain/122.1.5.