Cell therapy in murine atherosclerosis: in vivo imaging with high-resolution helical SPECT.

Purpose: To determine, the feasibility of in vivo localization and quantification of indium 111 (In-111)-oxine-labeled bone marrow (BM) with high-resolution whole-body helical single photon emission computed tomography (SPECT) in an established murine model of atherosclerosis and vascular repair. Materails and Methods: The institutional animal care and use committee approved this study. BM From young 136 Rosa 26 Lac Z(+/+) mice was radiolabeled with In-111-oxine. On days 1, 4, and 7, after. administration of radiolabeled cells, five C57/BL6 apoli-poprotein E-deficient mice and five wild-type (WT) control mice were imaged with whole-body high-resolution helical SPECT. Quantification with SPECT was compared with ex vivo analysis by means of gamma, counting. Autoradiography and beta-galactosidase staining were used to verify donor cell biodistribtition. Linear regression was used to assess the correlation between continuous variables. Two-tailed Student t test was used to compare values between groups, and paired two-tailed t test was used to assess changes within subjects at different time points. Results: SPECT image contrast was high, with cleat, visualization of BM, liver, and spleen 7 days after administration of radiolabeled cells. SPECT revealed that 42% and 58% more activity was localized to the aorta and BM (P < .05, for both), respectively, in apolipoprotein E-deficient mice versus WT mice. Furthermore, 28% and 27% less activity was localized to the liver and spleen (P < .05 For both), respectively, in apolipoprotein E-deficient mice versus WT mice. SPECT and organ gamma counts showed good quantitative correlation (r = 0.9). beta-Galactosidase staining and microautoradiography of recipient aortas showed donor cell localization to the intima of visible atherosclerotic plaque but. not to unaffected regions of the vessel wall. Conclusion: High-resolution in vivo helical pinhole SPECT can be used to monitor and quantify early biodistribution of In-111-oxine-labeled BM in a marine model of progenitor cell therapy for atherosclerosis.