Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Carnegie Mellon develops non-invasive technique to detect transplant rejection at cellular level

24.01.2006


Research could revolutionize care of transplant patients

Carnegie Mellon University scientist Chien Ho and his colleagues have developed a promising tool that uses magnetic resonance imaging (MRI) to track immune cells as they infiltrate a transplanted heart in the early stages of organ rejection. This pre-clinical advance, described in an upcoming issue of the Proceedings of the National Academy of Sciences (PNAS), ultimately could provide a non-invasive way to detect transplant rejection in patients.

"We have reported for the first time the ability to monitor single immune cells in a live animal using MRI. This could revolutionize the management of transplant patients," said Ho, professor of biological sciences at the Mellon College of Science.

"Successful translation of this work to the clinic ultimately will reduce the number of biopsy procedures and should greatly improve the quality of life for cardiac transplant patients, especially children," added Ho, who directs the Pittsburgh NMR Center for Biomedical Research. "Perhaps most importantly, this advance will allow doctors to provide highly personalized care that could prevent transplant rejection."

Organ transplantation is the preferred clinical approach to treat end-stage organ failure, but transplant patients face a lifetime of immunosuppressive therapy and the risk of losing the new organ due to rejection. Physicians typically monitor patients for organ rejection following a heart transplant by performing frequent heart biopsies for the first year. Heart biopsies are invasive procedures that involve threading a catheter through the jugular vein to the heart’s right ventricle and snipping out several tiny pieces of tissue. A pathologist then tests the tissue to identify the presence of immune cells (such as macrophages) as well as other pathological changes in the transplanted heart tissue that indicate the graft is being rejected by the body’s immune system.

These procedures are costly, uncomfortable and must be repeated annually for a few years to monitor and treat any rejection. Biopsies also are problematic, according to Ho, because they do not look at the whole organ. By only sampling several small areas, a biopsy may miss the area of the transplanted organ where immune cells are gathering -- one of the first signs of rejection.

Ho’s novel approach investigates transplant rejection non-invasively by observing macrophage accumulation in heart tissues using MRI.

"We were able to use MRI to visualize individual macrophages. By tracking individual cells, we also were able to observe, for the first time, that rejection progresses from the outside of the heart to the inside," said Ho. "Up to now, this phenomenon hasn’t been observed in pre-clinical or clinical research because biopsy samples are very limited in location and size."

The reported findings also have broader implications for biology and medicine, according to Ho.

"We now have the ability to visualize non-invasively and with sensitivity individual cells and their movement to targeted sites. Our new approach offers almost unlimited potential for monitoring cell therapies, such as those using stem cells, and for tracking cellular and developmental processes," Ho said.

For the research reported in PNAS, Yijen Wu, research biologist at the Pittsburgh NMR Center for Biomedical Research, tagged macrophages with nanometer (USPIO)- or micrometer (MPIO)-sized paramagnetic iron oxide particles, which are very sensitive to the magnetic fields used during MRI. Wu injected the MPIO or USPIO particles into rats that had received heart transplants three days earlier. Macrophages, which typically ingest foreign materials inside the body (bacteria, for example), incorporated the particles. Using MRI, the researchers then track tagged macrophages that infiltrate transplanted hearts. The locations of the tagged macrophages are highly defined and appear circular in shape, said Wu. This finding indicates that the new, real-time tracking method is very good at pinpointing exactly when and where rejection is taking place.

The researchers used a heterotropic heart model to study organ rejection. In this model, a rat receives a second functional heart, which is grafted into its abdomen. The rat’s native heart functions normally. In this way, the researchers can study how a transplanted heart changes through sequential stages of rejection while the rat stays healthy. This aspect of the research was conducted primarily by Qing Ye, a research biologist at the Pittsburgh NMR Center for Biomedical Research.

Ho’s team at the Pittsburgh NMR Center for Biomedical Research is now pursuing research using larger animal models. They are collaborating with researchers at the University of Pittsburgh School of Medicine, including Dr. David Cooper, professor of surgery in the Thomas E. Starzl Transplantation Institute; Dr. Jeffrey Teuteberg, assistant professor of medicine at the Cardiovascular Institute, Heart Failure/Transplantation; and Dr. Fernando Boada, associate professor in the Department of Radiology.

Lauren Ward | EurekAlert!
Further information:
http://www.andrew.cmu.edu

More articles from Medical Engineering:

nachricht New imaging technique able to watch molecular dynamics of neurodegenerative diseases
14.07.2017 | The Optical Society

nachricht Quick test finds signs of sepsis in a single drop of blood
03.07.2017 | University of Illinois at Urbana-Champaign

All articles from Medical Engineering >>>

The most recent press releases about innovation >>>

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

Im Focus: Manipulating Electron Spins Without Loss of Information

Physicists have developed a new technique that uses electrical voltages to control the electron spin on a chip. The newly-developed method provides protection from spin decay, meaning that the contained information can be maintained and transmitted over comparatively large distances, as has been demonstrated by a team from the University of Basel’s Department of Physics and the Swiss Nanoscience Institute. The results have been published in Physical Review X.

For several years, researchers have been trying to use the spin of an electron to store and transmit information. The spin of each electron is always coupled...

Im Focus: The proton precisely weighted

What is the mass of a proton? Scientists from Germany and Japan successfully did an important step towards the most exact knowledge of this fundamental constant. By means of precision measurements on a single proton, they could improve the precision by a factor of three and also correct the existing value.

To determine the mass of a single proton still more accurate – a group of physicists led by Klaus Blaum and Sven Sturm of the Max Planck Institute for Nuclear...

Im Focus: On the way to a biological alternative

A bacterial enzyme enables reactions that open up alternatives to key industrial chemical processes

The research team of Prof. Dr. Oliver Einsle at the University of Freiburg's Institute of Biochemistry has long been exploring the functioning of nitrogenase....

Im Focus: The 1 trillion tonne iceberg

Larsen C Ice Shelf rift finally breaks through

A one trillion tonne iceberg - one of the biggest ever recorded -- has calved away from the Larsen C Ice Shelf in Antarctica, after a rift in the ice,...

Im Focus: Laser-cooled ions contribute to better understanding of friction

Physics supports biology: Researchers from PTB have developed a model system to investigate friction phenomena with atomic precision

Friction: what you want from car brakes, otherwise rather a nuisance. In any case, it is useful to know as precisely as possible how friction phenomena arise –...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

»We are bringing Additive Manufacturing to SMEs«

19.07.2017 | Event News

The technology with a feel for feelings

12.07.2017 | Event News

Leipzig HTP-Forum discusses "hydrothermal processes" as a key technology for a biobased economy

12.07.2017 | Event News

 
Latest News

Researchers create new technique for manipulating polarization of terahertz radiation

20.07.2017 | Information Technology

High-tech sensing illuminates concrete stress testing

20.07.2017 | Materials Sciences

First direct observation and measurement of ultra-fast moving vortices in superconductors

20.07.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>