Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

New way out: Researchers show how stem cells exit bloodstream

29.06.2016

Researchers at North Carolina State University have discovered that therapeutic stem cells exit the bloodstream in a different manner than was previously thought. This process, dubbed angiopellosis by the researchers, has implications for improving our understanding of not only intravenous stem cell therapies, but also metastatic cancers.

When white blood cells need to get to the site of an infection, they can exit the bloodstream via a process called diapedesis. In diapedesis, the white blood cell changes its shape in order to squeeze between or through the epithelial cells that form the walls of the blood vessel.


A stem cell exits the bloodstream through angiopellosis.

Credit: Alice MacGregor Harvey, NC State University

Diapedesis is a well-understood process, and researchers believed that other types of cells, like therapeutic stem cells or even metastatic cancer cells, exited blood vessels in a similar way - with the cells pushing or squeezing themselves out.

But a group of researchers led by Ke Cheng, associate professor of molecular biomedical sciences at NC State with a joint appointment in the NC State/UNC-Chapel Hill Department of Biomedical Engineering, found that these stem cells behaved differently.

Therapeutic stem cells share the same ability to exit the bloodstream and target particular tissues that white blood cells do. But the precise way that they did so was not well understood, so Cheng and his team utilized a zebrafish model to study the process.

The genetically modified zebrafish embryos were transparent and had fluorescently marked green blood vessels. Researchers injected the embryos with white blood cells and cardiac stem cells from humans, rats and dogs. These cells had all been marked with a red fluorescent protein.

Through time-lapse three-dimensional light sheet microscopic imaging, Cheng and his team could trace the progress of these cells as they left the blood vessel. The white blood cells exited via diapedesis, as expected. When stem cells exited the blood vessel, however, the endothelial cells lining the vessel actively expelled them. Membranes surrounding the endothelial cells on either side of the stem cell stretched themselves around the stem cell, then met in the middle to push the stem cell out of the vessel.

"When you're talking about diapedesis, the white blood cell is active because it changes its shape in order to exit. The endothelial cells in the blood vessel are passive," Cheng says. "But when we looked at therapeutic stem cells, we found the opposite was true - the stem cells were passive, and the endothelial cells not only changed their shape in order to surround the stem cell, they actually pushed the stem cells out of the blood vessel. We've named this process angiopellosis, and it represents an alternative way for cells to leave blood vessels."

The researchers found two other key differences between angiopellosis and diapedesis: one, that angiopellosis takes hours, rather than minutes, to occur; and two, that angiopellosis allows more than one cell to exit at a time.

"Angiopellosis is really a group ticket for cells to get out of blood vessels," Cheng says. "We observed clusters of cells passing through in this way. Obviously, this leads us to questions about whether other types of cells, like metastatic cancer cells, may be using this more effective way to exit the bloodstream, and what we may need to do to stop them."

###

The research is published in Stem Cells. Tyler Allen, a graduate student in the comparative biomedical sciences program, is the first author of the paper. The research was supported by the National Institutes of Health and the American Heart Association.

-peake-

Note to editors: An abstract of the paper follows

"Angiopellosis as an alternative mechanism of cell extravasation"

DOI: 10.1002/stem.2451

Authors: Tyler Allen, Jhon Cores, Adam Vandergriff, Ke Cheng, NC State Department of Molecular Biomedical Sciences and joint Department of Biomedical Engineering, NC State and UNC-Chapel Hill; David Gracieux, Maliha Talib, Debra Tokarz, M. Taylor Hensley, James B.M. de Andrade, Phuong-Uyen Dinh, Jeffrey Yoder, North Carolina State University: Junnan Tang, First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China

Published: Online in Stem Cells

Abstract:

Stem cells possess the ability to home in and travel to damaged tissue when injected intravenously. For the cells to exert their therapeutic effect, they must cross the blood vessel wall and enter the surrounding tissues. The mechanism of extravasation injected stem cells employ for exit has yet to be characterized. Using intravital microscopy and a transgenic zebrafish line tg(Fli1a:egpf) with GFP-expressing vasculature, we documented the detailed extravasation processes in vivo for injected stem cells in comparison to white blood cells (WBCs). While WBCs left the blood vessels by the standard diapedesis process, injected cardiac and mesenchymal stem cells underwent a distinct method of extravasation that was markedly different from diapedesis. Here, the vascular wall undergoes an extensive remodeling to allow the cell to exit the lumen, while the injected cell remains distinctively passive in activity. We termed this process Angio-pello-sis, which represents an alternative mechanism of cell extravasation to the prevailing theory of diapedesis.

Media Contact

Tracey Peake
tracey_peake@ncsu.edu
919-515-6142

 @NCStateNews

http://www.ncsu.edu 

Tracey Peake | idw - Informationsdienst Wissenschaft

More articles from Life Sciences:

nachricht New printing technique uses cells and molecules to recreate biological structures
20.02.2018 | Queen Mary University of London

nachricht In living color: Brightly-colored bacteria could be used to 'grow' paints and coatings
20.02.2018 | University of Cambridge

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: In best circles: First integrated circuit from self-assembled polymer

For the first time, a team of researchers at the Max-Planck Institute (MPI) for Polymer Research in Mainz, Germany, has succeeded in making an integrated circuit (IC) from just a monolayer of a semiconducting polymer via a bottom-up, self-assembly approach.

In the self-assembly process, the semiconducting polymer arranges itself into an ordered monolayer in a transistor. The transistors are binary switches used...

Im Focus: Demonstration of a single molecule piezoelectric effect

Breakthrough provides a new concept of the design of molecular motors, sensors and electricity generators at nanoscale

Researchers from the Institute of Organic Chemistry and Biochemistry of the CAS (IOCB Prague), Institute of Physics of the CAS (IP CAS) and Palacký University...

Im Focus: Hybrid optics bring color imaging using ultrathin metalenses into focus

For photographers and scientists, lenses are lifesavers. They reflect and refract light, making possible the imaging systems that drive discovery through the microscope and preserve history through cameras.

But today's glass-based lenses are bulky and resist miniaturization. Next-generation technologies, such as ultrathin cameras or tiny microscopes, require...

Im Focus: Stem cell divisions in the adult brain seen for the first time

Scientists from the University of Zurich have succeeded for the first time in tracking individual stem cells and their neuronal progeny over months within the intact adult brain. This study sheds light on how new neurons are produced throughout life.

The generation of new nerve cells was once thought to taper off at the end of embryonic development. However, recent research has shown that the adult brain...

Im Focus: Interference as a new method for cooling quantum devices

Theoretical physicists propose to use negative interference to control heat flow in quantum devices. Study published in Physical Review Letters

Quantum computer parts are sensitive and need to be cooled to very low temperatures. Their tiny size makes them particularly susceptible to a temperature...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

2nd International Conference on High Temperature Shape Memory Alloys (HTSMAs)

15.02.2018 | Event News

Aachen DC Grid Summit 2018

13.02.2018 | Event News

How Global Climate Policy Can Learn from the Energy Transition

12.02.2018 | Event News

 
Latest News

Major discovery in controlling quantum states of single atoms

20.02.2018 | Physics and Astronomy

New printing technique uses cells and molecules to recreate biological structures

20.02.2018 | Life Sciences

New tech for commercial Lithium-ion batteries finds they can be charged 5 times fast

20.02.2018 | Power and Electrical Engineering

VideoLinks
Science & Research
Overview of more VideoLinks >>>