Why is collagen so important, anyway?
By Guest Author, Samantha Geiger
Hey everyone! Before I dig into some science, I’d like to take a second to introduce myself. My name is Sam and I’m a veterinary medicine student at UW-Madison (I also have a BS in microbiology and genetics), science enthusiast, and fellow zebra. I’m very passionate about science communications and making difficult-to-understand concepts more accessible to people with non-scientific backgrounds. When it comes to EDS, I strongly believe that understanding the biology behind the disease empowers patients and allows them to ask their doctors the right questions to get proper care. Additionally, I want to provide resources for medical professionals so they may learn to care for patients with diseases they may not be familiar with – I’ll be leaving citations at the end of each post for this purpose. I’m exceedingly grateful to EDS WI, Inc. for giving me this opportunity. As this is my first post, I thought it would be fitting to discuss what collagen is, why it’s so important, and why it can cause different manifestations amongst EDS subtypes.
I also want to take a second and clarify a critical point: genes set the template for the body to make proteins, and proteins are the workhorses of the body. Proteins are what actually “do” things and carry out a function. If you have bad blueprints – mutated genes – your body doesn’t make a normal protein. Sometimes, like in the case of EDS, these abnormal proteins can have noticeable effects in the body. Proteins are made in different parts of the body at different levels due to a mechanism called “gene expression.” This is why you have nails at the end of your fingers instead of on your forehead!
Most of us know that collagen is a foundational protein found throughout the body and that it’s essentially a “building block” for different structures, but did you know there have been 29 different collagen proteins identified to date? Some of them are more common or have a bigger impact on the body when they don’t work properly compared to others. The first five types are perhaps the most important and well-understood:
- Type I collagen is by far the most common in the body and makes up parts of your skin, tendons and ligaments, blood vessels, and bones. It often works in partnerships with other kinds of collagen.
- Type II is a huge component of cartilage.
- Types III, IV, and V help anchor cells to each other (using what’s called a “reticular fiber”) and to other types of tissue, in some cases forming barriers called “basement membranes” underneath layers of cells. These collagen types are important for microscopic, cell-to-cell activity.
As you can see, each collagen type has its own job to do, which is why there are different subtypes of EDS that can be described by which collagen protein isn’t working. For example, mutations in type III collagen can cause vEDS. This makes sense because the fibers type III makes are critical for forming the architecture of the heart and major blood vessels and give them the ability to stretch and accommodate changing amounts of blood.
Some types of EDS don’t have collagen mutations at all! In these cases, proteins in the body that have to work with or use collagen are mutated and lose their ability to do their jobs. Essentially, the body’s collagen is fine but it can’t be used properly. In periodontal EDS, C1R, a gene involved in a specific part of the immune system, is mutated and collagen is normal. However, the culprit protein uses collagen to make itself. When C1R can’t do its job, the mouth ends up becoming very inflamed, which can cause dental problems.
We’ve all heard the metaphor that likens collagen in the body to building a house. If you have a crummy foundation – mutated collagen – the house will probably wear out more quickly than it should. To add some nuance to the metaphor, imagine collagen is the wood you use to build your house. It forms the walls, the roof, the floor, and maybe some structures inside like cabinets and doors. All in all, pretty important structures to have in a place to live, right? If all of your wood is bad, it’s going to have pretty serious effects throughout the house. Maybe only the wood you use for your roof is bad – your walls will still stand, but maybe some rain leaks in through the ceiling. Maybe your carpenters don’t know how to use the perfectly fine wood you bought, and that’s the reason your floor caves in.
Thinking about collagen this way can be a really helpful tool for understanding why different types of EDS exist. There isn’t just one type of EDS, just as there isn’t one purpose for the wood you buy to build a house. Medically, you don’t treat similarly or lump together patients with different types of EDS, much like you don’t have your carpenter install your plumbing.
*Disclaimer: I am not a physician, and I am not qualified to give anyone advice about their medical condition. All posts written by me are strictly meant to inform and empower patients and medical professionals alike, with information they can use to better communicate with each other. If you have questions about your condition, please ask your doctor.
Citations:
https://www.ehlers-danlos.com/eds-types
Preparation and characterization of the different types of collagen. Miller EJ, Rhodes RK. 1982. Methods Enzymol. 82 Pt A 33-64.
Collagen: a overview. Miller EJ, Gay S. 1982. Methods Enzymol. 82: 3-32.
Elastic and Collagenous Networks in Vascular Diseases. Arteaga-Solis E, Gayraud B, Ramirez F. 2011. Cell Struct. 25(2):69-72.
Periodontal Ehlers-Danlos Syndrome is caused by mutations in C1R and C1S, which encode subcomponents C1r and C1s of complement. Kapferer-Seebacher I, Pepin M, Werner R, et al. 2016. AJHG. 99(5):1005-1014.
