This is the second part of a 3-part series about the discovery of this “new” organ you’ve heard so much about. For the first part, go here.
Let’s discuss fascia first
What is fascia? Though recognized for centuries, attention wasn’t paid to this system of the body that not only separates but connects everything. We know from research papers that fascia is subject to mechanical forces, stretching, compression, and basic movement. It reacts, responds, adapts, and even is pre-stressed prior to movement. There have been more findings on telocytes, fibroblasts, collagen, and other substances in the extracellular matrix, and I wonder if telocytes may actually play a role here as a transient cell the authors found but didn’t specify. I’m not sure but I feel like they play a role in all of this too.
Often in my lectures and trainings, I share a simplistic way of visualizing fascia. Think of it like a sponge. Inside this sponge, you have fluid and the holes have some specialized structures. The question I frequently propose is, what happens when you squeeze the sponge? Do the cells around the holes react?
When connective tissue is subjected to mechanical forces (compression or pull or even breathing) or in your gut (peristalsis), how do these movements impact the “sponge-like” qualities of the extracellular matrix?
On to the research paper
What was cool about this particular paper is that the doctors used a confocal laser microscope, which is different than what most histological biopsies use. Using this type of laser allows you to fix a tissue, put it under a microscope, and not cut it. This microscope creates a very specific image, which you can put together in three dimensions in a computer. (Don’t you love technology?) This has been used before, but now you can do this in vivo (in a living body). So researchers and doctors are starting to use these tools during a biopsy so you can take a picture and not take any tissue out at all while it’s still in a body. So cool. One reason I’m such a science geek.
In this article, they recognized that fascia had an inherent connection to the lymphatic system. Their findings suggest that fluid from the fascia or interstitium drains into the lymph nodes. The idea of pre-lymphatic is important because the lymphatic channels collect fluid from the tissues, like roots of a tree.
I’m not aware that this was ever seen in the way these doctors saw it using those microscopes, but I think being able to demonstrate it was really the most compelling finding of the paper.
When you cut through a section, no matter how it’s been cut, there are artifacts that exist. No matter the skill, if you use a knife, you make an artifact. With the confocal laser microscope, the authors of the paper realized the marks they saw weren’t artifacts or rips in the cells caused by the blade but rather well-defined cavities. This, they realized, worthy of some more viewing and consideration.
Yet the curiosity for me is their finding that these spaces are lined on one side with cells but that the other side doesn’t have cells. The collagen and interstitial fluid have connection on the other side instead.
The histologists kept taking deeper and deeper slices into the fascia of the bile duct. When they got to about 60 microns, they started seeing a honeycomb structure or something that looked like a sponge. This just got me excited because I’ve been talking about it like a sponge for so long.
The researchers used fluorescein (widely used as a fluorescent tracer in microscopy to see stuff better) and injected it intravenously to highlight structures. So what appears white in the images is what’s highlighted by fluorescein and the holes are black in the images.
They took the tissue out and repeated the same process out of the body and didn’t cut the tissue, they used the same confocal laser microscope, and they saw pretty much the same thing. So now the stain would adhere to the membranes and then they viewed it under microscopy and it reverses the process so once the fluorescein dies out, you can really see what’s there.
Join me Wednesday for the conclusion of this 3-part blog series, including my conclusions from this study – and a few questions I still have.