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 Can radar replace stethoscopes?
14.08.2018 | Friedrich-Alexander-Universität Erlangen-Nürnberg

nachricht Novel PET imaging method could track and guide therapy for type 1 diabetes
03.08.2018 | Society of Nuclear Medicine and Molecular Imaging

All articles from Medical Engineering >>>

The most recent press releases about innovation >>>

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

Im Focus: It’s All in the Mix: Jülich Researchers are Developing Fast-Charging Solid-State Batteries

There are currently great hopes for solid-state batteries. They contain no liquid parts that could leak or catch fire. For this reason, they do not require cooling and are considered to be much safer, more reliable, and longer lasting than traditional lithium-ion batteries. Jülich scientists have now introduced a new concept that allows currents up to ten times greater during charging and discharging than previously described in the literature. The improvement was achieved by a “clever” choice of materials with a focus on consistently good compatibility. All components were made from phosphate compounds, which are well matched both chemically and mechanically.

The low current is considered one of the biggest hurdles in the development of solid-state batteries. It is the reason why the batteries take a relatively long...

Im Focus: Color effects from transparent 3D-printed nanostructures

New design tool automatically creates nanostructure 3D-print templates for user-given colors
Scientists present work at prestigious SIGGRAPH conference

Most of the objects we see are colored by pigments, but using pigments has disadvantages: such colors can fade, industrial pigments are often toxic, and...

Im Focus: Unraveling the nature of 'whistlers' from space in the lab

A new study sheds light on how ultralow frequency radio waves and plasmas interact

Scientists at the University of California, Los Angeles present new research on a curious cosmic phenomenon known as "whistlers" -- very low frequency packets...

Im Focus: New interactive machine learning tool makes car designs more aerodynamic

Scientists develop first tool to use machine learning methods to compute flow around interactively designable 3D objects. Tool will be presented at this year’s prestigious SIGGRAPH conference.

When engineers or designers want to test the aerodynamic properties of the newly designed shape of a car, airplane, or other object, they would normally model...

Im Focus: Robots as 'pump attendants': TU Graz develops robot-controlled rapid charging system for e-vehicles

Researchers from TU Graz and their industry partners have unveiled a world first: the prototype of a robot-controlled, high-speed combined charging system (CCS) for electric vehicles that enables series charging of cars in various parking positions.

Global demand for electric vehicles is forecast to rise sharply: by 2025, the number of new vehicle registrations is expected to reach 25 million per year....

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

LaserForum 2018 deals with 3D production of components

17.08.2018 | Event News

Within reach of the Universe

08.08.2018 | Event News

A journey through the history of microscopy – new exhibition opens at the MDC

27.07.2018 | Event News

 
Latest News

Quantum bugs, meet your new swatter

20.08.2018 | Information Technology

A novel synthetic antibody enables conditional “protein knockdown” in vertebrates

20.08.2018 | Life Sciences

Metamolds: Molding a mold

20.08.2018 | Information Technology

VideoLinks
Science & Research
Overview of more VideoLinks >>>