Thanks Sucker

When I was a little kid, my family used to visit our cousins at their cottage in Muskoka (a summer retreat area for many Ontario residents).  Anyway, their cottage was on a lake and my sister and I and our two cousins would spend practically all day swimming and jumping off of the dock. 

This was paradise for us except for one little drawback...the leeches.  Unfortunately, several freshwater lakes in this area are home to these little blood-suckers.  Usually they weren't a problem and it was rare to ever get "bitten" by one of them but, I will never forget how scared I was by the threat of it.  They're kind of like swimming mosquitos right!?  Yuck. 


Well, perhaps I was too tough on these little creatures, because it turns out that leeches and their saliva may actually be beneficial in the treatment of MS.

Leeches belong to the same family as the common earthworm and there are three main types: marine, freshwater and terrestrial.  There are many species of leeches that do not feed on human blood and prefer to consume invertebrates like gnats, insect larvae, water bugs and snails.

The type of sucker used in medicine is a Haemophagic leech; they attach to their host and feed on it's blood until full.  The little guys (or girls - leeches are all hermaphrodites) are courteous though and release an anesthetic so their host doesn't feel them at all.  When they're satisfied, they let go and take off to go digest their meal.  I wonder if it's like Thanksgiving and all the little leeches hang out on a log after dinner and watch the equivalent of football?...

Researchers believe that leeches are beneficial to MS patients because of an anticoagulant, or blood thinner, that they secrete in their saliva called hirudin.  This stops the clotting of blood and allows the leeches to have a steady drink.  When studying the over 2 500 proteins from the brains of MS patients, researchers found something interesting.

In MSers, two proteins known as tissue factor and protein C inhibitor showed signs of damage that was not present in healthy brains. These two proteins are responsible for controlling the clotting of blood.

So, it is thought that these damaged proteins form a kind of scaffold for T-cells/immune cells to build on, allowing them to gain access to the blood-brain barrier.  When T-cells cross through the barrier and get into the brain, it's party time.  They wreak havoc on our myelin (the brain's insulating material) causing damage and the furthering of MS - remember the post on caffeine ("Cuppa Joe")? These theories are all related...

With this information in hand, researchers decided to try out a medicine derived from the leech's hirudin to treat mice with the animal-equivalent of MS.  And guess what?  It worked!  Hirudin was able to break down the "scaffolding" effect caused by the damaged brain proteins and prevent T-cells from ever crossing the blood-brain barrier.  Like the caffeine solution, both of these treatments focus on preventing T-cells/immune cells from ever getting into the brain in the first place.

Again, these lucky little mice are getting their MS cured and we humans are all waiting around for more studies.  Basically, scientists need to find something along these lines that wouldn't cause an anti-coagulating effect in the entire body and wouldn't cause bleeding.

Even if we aren't getting these treatment options as fast as we'd like, we are getting new information into the nature of our disease.  What makes it tick, why this is happening to us and how this is happening to us.  Until we get more answers, I'd just like to say a huge thank you to the little bees, mice and leeches that are helping us out for now, just by being them.

Next time I go swimming in a leech-ey lake, I won't be scared at all.  Maybe I'll go skinny-dipping instead and let the leeches go to town instead!  Free alternative medicine, compliments of Mother Nature!