PET and Bioluminescent Imaging Aid Evaluation of Stem Cells' Potential for New Ways to Treat DiseaseDecember 07, 2007Journal of Nuclear Medicine Articles Focus on "Immense Potential" for Stem Cell-Based Therapies RESTON, Va.-Using positron emission tomography (PET) imaging with bioluminescence-the light produced by a chemical reaction within an organism-researchers are starting to understand the behavior of transplanted or implanted stem cells that may one day be used to develop new treatments for disease. According to a study in the December Journal of Nuclear Medicine, scientists have found that using the unique combination of noninvasive PET imaging and optical (bioluminescent) imaging is "an ideal method for tracking stem cell transplantation in small animal models," said Zhenghong Lee, an associate professor of nuclear medicine/radiology and biomedical engineering departments at Case Western Reserve University in Cleveland, Ohio. Researchers were able to use these two imaging techniques to "follow" stem cells for a longer time than previously had been achieved to determine their "fate," explained Lee.
Human mesenchymal stems cells or multipotent marrow stromal cells (hMSCs) are self-renewing adult stem cells that are found in adult donor bone marrow. These stem cells, the body's blank or "master" cells, may differentiate (or change) into bone, fat tissue and cartilage, said Lee. "The promise of MSC therapies-derived from adult bone marrow and used as a viable and renewable source of stem cells-mandates research leading to a better understanding of the long-term fate and trafficking of transplanted MSCs in animal and human subjects," said the investigator at Case Western's Center for Stem Cell and Regenerative Medicine. These progenitor cells may have great potential in providing future treatments for heart diseases, brain disorders and cancer and greatly reduce the need to use embryonic stem cells or other fetal tissues. Specifically, this imaging research could help optimize treatments for individuals with graft-versus-host disease, a life-threatening condition where immune cells from donated marrow or cord blood attack the body of a bone marrow transplant patient, said Lee. Additionally, bone marrow stem cells may help regenerate cells in individuals with heart disease (heart attacks) or brain disorders (strokes, multiple sclerosis) or bone fractures. They could act as a drug delivery vehicle for cancer patients, he added. Much research in these areas still needs to be done "since there are many things that we don't know about stem cell biology," noted Lee. For this study, researchers used a fusion protein combining firefly luciferase (a light-emitting substance) for optical imaging, a red fluorescent protein for cell separation and a virus enzyme thymidine kinase for PET imaging in mice to visualize biological processes at the molecular level. "The triple-fusion reporter approach resulted in a reliable method of labeling stem cells for investigation by use of both small-animal PET imaging and bioluminescent imaging," said Lee. PET is a powerful molecular imaging procedure that noninvasively demonstrates the function of genes, cells and organs/tissues, providing information about the biochemistry processes, metabolic activities and body functions. PET scans use very small amounts of radioactive pharmaceuticals that are detected or "traced" by a special type of camera that works with computers to provide quantitative pictures of the area of the body being imaged. To image dim light from bioluminescence-the process of light emission in living organisms-researchers use an ultra-sensitive camera from an external vantage point. This research is detailed in "Imaging of Mesenchymal Stem Cell Transplant by Bioluminescence and PET." In a related Journal of Nuclear Medicine article, the growing number of exciting animal and preclinical studies are explored, revealing the "immense potential in stem cell-based therapies, particularly in the area of treating cardiovascular diseases," said Joseph C. Wu, assistant professor of cardiovascular medicine and radiology at Stanford University School of Medicine in Stanford, Calif. Wu and co-author Sarah J. Zhang review the basic principles of current techniques for cardiac stem cell tracking, compare the relative advantages and disadvantages of these imaging modalities and discuss the future prospect of cardiac stem cell trafficking. "Comparison of Imaging Techniques for Tracking Cardiac Stem Cell Therapy" is the first article in the journal's new monthly feature called "Focus on Molecular Imaging." "The unique information obtained from molecular imaging techniques is particularly helpful in evaluating cell engraftment and may shed light on the mixed findings regarding stem cell-based therapy," said Wu. "The current noninvasive imaging approaches for tracking stem cells in vivo include imaging with magnetic particles, radionuclides, quantum dots, reporter genes, and fluorescence and bioluminescence imaging," he added. "It is possible that a tailored combination of two or more techniques may provide the most ideal information profile for clinical applications," concluded Wu. Additional co-authors of "Imaging of Mesenchymal Stem Cell Transplant by Bioluminescence and PET" include Zachary Love, nuclear medicine/radiology department; Fangjing Wang and Nicholas Salem, biomedical engineering department; Amad Awadallah, orthopedics department, James Dennis, orthopedics department and Center for Stem Cell and Regenerative Medicine, and Yuan Lin, hematology/oncology department, all at Case Western Reserve University in Cleveland, Ohio; and Andrew Weisenberger and Stan Majewski, Thomas Jefferson National Accelerator Facility, Newport News, Va. "Comparison of Imaging Techniques for Tracking Cardiac Stem Cell Therapy" was co-written by Wu and Sarah J. Zhang, Stanford University School of Medicine, Stanford, Calif. Society of Nuclear Medicine Science News and Science Current Events Tag Cloud This tag cloud is a visual representation of term frequencies of random science news topics with common terms grouped together and emphasized by their display size. 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Related Positron Emission Tomography Current Events and Positron Emission Tomography News Articles Study shows PET can measure effectiveness of novel breast cancer treatment A new study published in the July issue of The Journal of Nuclear Medicine shows that positron emission tomography (PET) scans in mice can be used to determine whether a novel type of breast cancer treatment is working as intended. Prototype Breast Cancer Imaging System May Improve Patient Care A prototype breast imaging system combining positron emission tomography (PET) and magnetic resonance imaging (MRI) technologies could greatly improve breast cancer imaging capabilities, according to researchers at SNM's 56th Annual Meeting. Hybrid Scanner Brings Molecular Functioning to the Forefront A major barrier to developing a hybrid positron emission tomography (PET)/magnetic resonance (MR) imaging system could be removed by using a novel approach for reconstructing data. PET Scans May Improve Accuracy of Dementia Diagnosis A new study shows that the use of positron emission tomography (PET) scans may improve the accuracy of dementia diagnoses early in disease onset for more than one out of four patients. Why dishing does you good: U-M study Why does dishing with a girlfriend do wonders for a woman's mood? PET scan can non invasively measure early assessment of treatment for common type of breast cancer Non-invasive imaging can measure how well patients with the most common form of breast cancer - estrogen receptor positive type - respond to standard aromatase inhibitor therapy after only two weeks and shows similar findings that more invasive needle sampling identifies, according to a poster presentation to be presented at the ASCO annual meeting next week. Early detection of lung cancer: New data presented at multidisciplinary meeting New data from several studies evaluating new techniques for early diagnosis and treatment of lung cancer are being presented at the first European Multidisciplinary Conference on Thoracic Oncology (EMCTO) in Lugano, Switzerland (1-3 May 2009). Using PET/CT imaging, UCLA researchers can tell after a single treatment if chemotherapy is working Oncologists often have to wait months before they can determine whether a treatment is working. Now, using a non-invasive method, researchers at UCLA's Jonsson Comprehensive Cancer Center have shown that they can determine after a single cycle of chemotherapy whether the toxic drugs are killing the cancer or not. NCRP Report No. 160 on increased average radiation exposure of the US population Scientists at the American Association of Physicists in Medicine (AAPM) are offering additional background information to help the public avoid misinterpreting the findings contained in a report issued today by the National Council on Radiation Protection and Measurements (NCRP), a non-profit body chartered by the U.S. Congress to make recommendations on radiation protection and measurements. PET/CT May Improve Prognosis for Patients With Inflammatory Breast Cancer In the largest study to date to evaluate fluorodeoxyglucose positron emission tomography combined with computed tomography (FDG-PET/CT) in the initial staging of inflammatory breast cancer (IBC), researchers were able to identify the precise location and extent of metastasis (spread of disease), offering the potential for a better prognosis for patients with this rare, but aggressive form of breast cancer. More Positron Emission Tomography Current Events and Positron Emission Tomography News Articles |
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