A totally new type of blood vessel has been discovered hidden in human bones

We often think that bone is a structurally sound element, especially its hard outer layer called cortical bone.

But a new discovery of unseen hidden pbadages crossing these rigid organs in animals and humans could lead to rethinking the structure and function of basic skeletal anatomy.

In a new study, German researchers discovered an undetected network of thin blood vessels that act as a secret tunneling system inside the bone, thus helping the blood and immune cells to diffuse effectively and quickly throughout the body.

Elon Musk would probably agree.

"It is really unexpected to be able to find a new central anatomical structure that has not been described in any textbook in the 21st century," explains Matthias Gunzer, a molecular immunologist at the University of Duisburg-Essen.

(Grüneboom et al. / Nature Metabolism)

These tiny channels, called "trans-cortical vessels" (VCT), may be new to science, but they help explain how emergency drug infusions introduced into the battlefield have made it possible to quickly relive the wounded soldiers.

In such emergency situations, doctors do not always have the time or the ability to locate veins or access them, they inject drugs directly into the bone marrow.

"Despite evidence accumulating evidence of the presence of a complex blood supply in the bone, the molecular mechanisms and anatomy underlying these rapid cell and fluid movements of the bone marrow to the circulation remained inaccessible ", explains a comment on the new research.

Now, the basis of this mechanism is laid bare, after being spotted by accident several years ago. Gunzer was studying fluorescently stained blood cells in mice and was observing them under the microscope appearing to pbad through what should have been solid bone.

Unable to discover anything in the medical literature that could explain the phenomenon, he devised a new research project to explore what was happening.

In the new study, Gunzer's team used a chemical called ethyl cinnamate on the mouse's tibia (leg bone) to "clean" the bones, making them transparent.

Then, by combining Light Scanning Fluorescence Microscopy (LSFM) and X-ray microscopy, they were able to detect for the first time several hundred of these tiny TCVs crossing the cortical layer of the bones of the leg.

According to the researchers, a mouse tibia may contain more than 1,000 of these small capillaries and, surprisingly, the team indicates that more than 80% of the arterial blood and 59% of the venous blood pbad through the channels.

That's a lot of blood circulation for something that scientists did not even know.

"I've never seen such vessels," STAT's Ralph Müller, a biomechanics researcher at the Swiss Higher Institute of Technology, told STAT who was not involved in the study.

"But we've never really looked for it either, so it's a surprise to me … that will definitely require replication in other labs."

When the team examined the human anatomy by examining the leg bone of a human volunteer (Gunzer himself), she found evidence of the same type of TCV structures although they are thicker, and the researchers acknowledged that extra work was needed to confirm their exact function.

Regarding how these hidden pbadages have escaped our attention so far, the team explained that the technological breakthrough was due to advances in imaging technology, but they admitted to being surprised by the unexpected result.

"It's totally crazy, there are still things to be discovered about human anatomy," Gunzer said. New scientist.

"We found blood vessels in a new place we did not know before."

The discovery – reminiscent of another secret tunneling system in the skull revealed by a study conducted by Harvard last year – could give rise to all sorts of new medical leads for research on inflammatory diseases, tissue lesions, cell migration or simply understanding blood flow.

"The main bone diseases are badociated with changes in the CVT system," the authors write, "new research opportunities that further characterize the role of CVTs in skeletal biology and diseases may be considered".

The results are reported in Metabolism of nature.