New molecular imaging techniques may lead to advances in disease treatment

A promising new technique has been developed that will enable more accurate non-invasive positron emission tomography (PET) imaging of new cells injected into the body, according to researchers at SNM's 55th Annual Meeting. The new technique, which involves engineering antibody fragments to act as reporter genes—or markers that signal cells of interest for PET imaging purposes—could significantly advance the study of genetically engineered cells to treat diseases.

"Genetic cell engineering is the focus of intense research in almost all areas of medicine and shows great promise for treatment of common illnesses such as heart disease, diabetes, and Parkinson's disease and other neurodegenerative disorders," said Wolfgang Weber, lead researcher of the study, Cell Surface Expression of an Engineered Antibody as a PET Reporter Gene for In Vivo PET Imaging, which was performed at the Department of Molecular and Medical Pharmacology at UCLA in collaboration with the Department of Chemistry at UC Davis.

However, despite intense efforts, researchers have few solid, noninvasive methods for accurately tracking the location, function and viability of small numbers of transplanted cells. "Our research shows that using antibodies as reporter genes in PET imaging provides these capabilities and could contribute to improved treatment of a number of potentially devastating diseases," added Weber, now professor of nuclear medicine at the University of Freiburg, Germany.

To improve PET imaging in this area, researchers have been studying the use of reporter gene–probe combinations. With this technique, cells are created to synthesize a protein that binds to or metabolizes radioactive reporter probes that are injected into the body and detected with PET imaging technology. However, most available reporter gene combinations are not aptly sensitive or specific and have significant limitations in terms of tracking the cells of interest to researchers.

In this new research, Weber and his team explored using cell surface–bound antibody fragments as reporter genes. These engineered antibody fragments, developed by the group of Claude Meares at Davis, bind irreversibly to low-molecular-weight antigens, which act as reporter probes. Cell culture and animal studies demonstrated intense and highly specific uptake of the probes in cells expressing the antibody fragment on the cell surface. These data indicate that antibody-based reporter genes represent a promising new platform for the development of new reporter gene and probe combinations.

Antibody-based reporter genes have several potential advantages over other combinations. For example, the pharmacokinetics of the reporter probe can easily be optimized, and probes can identify antibodies with much higher specificity, thus improving the accuracy of PET imaging. In addition, the number of antibodies that can be used as reporter genes is virtually unlimited compared with available viral or mammalian reporter genes. Antibody-based reporter genes have low immunogenicity and are better suited for imaging the expression of several genes.

Source: Society of Nuclear Medicine

Related stories:

Researchers develop new PET scanning probe that will allowing monitoring of the immune system
Researchers at UCLA's Jonsson Comprehensive Cancer Center have modified a common chemotherapy drug to create a new probe for Positron Emission Tomography (PET), an advance that will allow them to model and measure the immune system in action and monitor response to new therapies.
Dividing cells find their middle by following a protein 'contour map'
Self-organization keeps schools of fish, flocks of birds and colonies of termites in sync. It’s also, according to new research, the way cells regulate the final stage of cell division. Scientists at Rockefeller University have shown that a protein-chemistry-based contour map, which helps individual proteins locate the center of their cell without direction from a “master organizer,” is key to ensuring accurate division during mitosis.
New technique developed for tracking cells in the body
Scientists' inability to follow the whereabouts of cells injected into the human body has long been a major drawback in developing effective medical therapies. Now, researchers at Johns Hopkins have developed a promising new technique for noninvasively tracking where living cells go after they are put into the body. The new technique, which uses genetically encoded cells producing a natural contrast that can be viewed using magnetic resonance imaging (MRI), appears much more effective than present methods used to detect injected biomaterials.
Researchers wake up viruses inside tumors to image and then destroy cancers
Researchers have found a way to activate Epstein-Barr viruses inside tumors as a way to identify patients whose infection can then be manipulated to destroy their tumors. They say this strategy could offer a novel way of treating many cancers associated with Epstein-Barr, including at least four different types of lymphoma and nasopharyngeal and gastric cancers.
Investigators take a fresh look at crime
Space scientists built advanced imaging tools to investigate the origins of the planets. Now they're working with forensic scientists to see if their tools can help investigate crime.
Bacteria which sense the Earth's magnetic field
Researchers uncover how a nanoscale 'compass' inside bacteria orients them to the Earth's magnetic field.
It is not only migratory birds that orient themselves to the magnetic field of the Earth. Also bacteria -- supposedly "simple" organisms -- have evolved to be able to take advantage of the magnetic field in their search for optimal living conditions. Such "magnetotactic"microorganisms use a miniature, cellular compass made of a chain of single nanomagnets, called magnetosomes.
Sensitive nanowire disease detectors made by Yale scientists
Yale scientists have created nanowire sensors coupled with simple microprocessor electronics that are both sensitive and specific enough to be used for point-of-care (POC) disease detection, according to a report in Nano Letters.
Q & A with John Lilly, CEO of Mozilla Corp.
John Lilly became chief executive of Mozilla Corp. in January, moving up from his role as chief operating officer. He's been with the company that created the open-source Firefox browser since 2005, the year Firefox 1.5 was released.

News discussion:

Medicine & Health news