In Vivo Tracking of Transplanted Mononuclear Cells Using Manganese-Enhanced Magnetic Resonance Imaging (MEMRI)

BACKGROUND: Transplantation of mononuclear cells (MNCs) has previously been tested as a method to induce therapeutic angiogenesis to treat limb ischemia in clinical trials. Non-invasive high resolution imaging is required to track the cells and evaluate clinical relevance after cell transplantation. The hypothesis that MRI can provide in vivo detection and long-term observation of MNCs labeled with manganese contrast-agent was investigated in ischemic rat legs. METHODS AND FINDINGS: The Mn-labeled MNCs were evaluated using 7-tesla high-field magnetic resonance imaging (MRI). Intramuscular transplanted Mn-labeled MNCs were visualized with MRI for at least 7 and up to 21 days after transplantation in the ischemic leg. The distribution of Mn-labeled MNCs was similar to that of ¹¹¹In-labeled MNCs measured with single-photon emission computed tomography (SPECT) and DiI-dyed MNCs with fluorescence microscopy. In addition, at 1-2 days after transplantation the volume of the site injected with intact Mn-labeled MNCs was significantly larger than that injected with dead MNCs, although the dead Mn-labeled MNCs were also found for approximately 2 weeks in the ischemic legs. The area covered by CD31-positive cells (as a marker of capillary endothelial cells) in the intact Mn-MNCs implanted site at 43 days was significantly larger than that at a site implanted with dead Mn-MNCs. CONCLUSIONS: The present Mn-enhanced MRI method enabled visualization of the transplanted area with a 150-175 µm in-plane spatial resolution and allowed the migration of labeled-MNCs to be observed for long periods in the same subject. After further optimization, MRI-based Mn-enhanced cell-tracking could be a useful technique for evaluation of cell therapy both in research and clinical applications

Role of Relative Myocardial Perfusion Reserve for Evaluating Stenosis Severity in Patients With Single-Vessel Coronary Artery Disease Using [13N] Ammonia and Positron Emission Tomography

A statistically significant correlation was observed between the severity of anatomic stenosis and coronaary flow reserve in experimental animals. A similar correlation in human coronary artery disease (CAD) was showing using positron emission tomography (PET) and pharmacologic vasodilator stress. The present study tested whether the concept of relative myocardial perfusion reserve (MPR) might be superior to absolute MPR in correlating coronary stenosis determined by quantitative coronary arteriography in patients with single vessel CAD using [13N] ammonia and PET. The study group comprised 21 patients (62 10 years old; 15 men, 6 women) with normal left venticular function who underwent angioplasty for isolated left anterior descending coronary artery stenosis. Absolute MPR, the ratio of dipyridamole-induced hyperemic blood flow to baseline blood flow by [13N] ammonia PET, and relative MPR, the ratio of MPR in regions supplied by stenosed coronary arteries to MPR in remote regions, were measured before and 3 months after angioplasty. The percent diameter stenosis was also quantified on coronary arteriograms just before the angiolasty and again at 3 months after. The study found that absolute MPR (r=0.755;p<0.0001) and relative MPR (r=0.814;p<0.0001) were inversely and nonlinearly correlated with the percent stenosis on angiography. The fitting curve of the correlation between relative MPR and coronary stenosis on angiography was identical to that observed in animal models. Therefore, relative MPR measured by [13N] ammonia PET more accurately and specifically describes stenosis severity in patients with CAD compared with absolute MPR, probably because of its independence from hemodynamic variations and the effects of coronary risk factors

INVOLVEMENT OF OAT3 IN THE ELIMINATION OF THE METABOLITE OF 99mTc-ETHYLENEDICYSTEINE DIETHYL ESTER FROM MICE BRAIN

日本薬物動態学会　第26回年会（広島

Involvement of organic anion transporter 3 in the efflux of 99mTc-L,L-ECD metabolite from mice brain

the 19th International Symposium on Radiopharmaceutical Science

In vivo recognition of cyclopentadienyltricarbonyl Rhenium and Technetium(CpTR, CpTT) derivatives.

7th Japan-China Joint Seminar on Radiopharmaceutical Chemistr