CX3CR1 deficiency impairs dendritic cell accumulation in arterial intima and reduces atherosclerotic burden.

OBJECTIVE: Dendritic cells (DCs) have recently been found in atherosclerosis-predisposed regions of arteries and have been proposed to be causal in atherosclerosis. The chemokine receptor CX3CR1 is associated with arterial injury and atherosclerosis. We sought to determine whether a link exists between arterial DC accumulation, CX3CR1, and atherosclerosis. METHODS AND RESULTS: Mouse aortas were isolated and subjected to en face immunofluorescence analysis. We found that DCs were located predominantly in the intimal regions of arterial branch points and curvatures. Consistent with the increased accumulation of intimal DCs in aged and ApoE-/- aortas compared with young WT aortas (P=0.004 and 0.05, respectively), the incidence of atherosclerosis was 88.9% for aged WT and 100% for ApoE-/- mice compared with 0% for young WT mice. CX3CR1 was expressed on intimal DCs and DC numbers were decreased in CX3CR1-deficient aortas of young, aged, and ApoE-/- mice (P=0.0008, 0.013, and 0.0099). The reduced DC accumulation in CX3CR1-deficiency was also correlated with decreased atherosclerosis in these animals. CONCLUSIONS: The accumulation of intimal DC increases in aged and ApoE-/- aortas and correlates with the generation of atherosclerosis. CX3CR1-deficiency impairs the accumulation of DC in the aortic wall and markedly reduces the atherosclerotic burden.

Neural substrates for motor imagery in severe hemiparesis.

BACKGROUND: The beneficial effects of imagined movements on motor learning and performance suggest that motor imagery is functionally close to preparatory and executive motor processes. OBJECTIVE: The purpose of this study was to examine the cortical processes associated with imagery of movement of the wrist in subjects with severe hemiparesis. METHODS: During fMRI, subjects with stroke performed alternating blocks of imagining wrist-tracking movements with the hemiparetic hand, active wrist-tracking movements with the unaffected hand, and resting. Control subjects performed the same tasks using an assigned hand. Cortical activation in the primary motor (M1), primary sensory (S1), supplementary motor area (SMA), and pre-SMA regions was determined through a laterality index of active voxels and signal intensity. Ability to imagine was assessed with an Imagery Rating Scale. RESULTS: All subjects displayed primarily contralateral control during the track condition. Healthy subjects demonstrated contralateral control in all areas during the imagine condition, whereas subjects with stroke displayed primarily contralateral activation in S1 but ipsilateral in M1 and SMA. The percentage change in signal intensity was greater in the ipsilateral hemisphere in subjects with stroke than in the ipsilateral hemisphere in healthy subjects during the imagine condition. Additionally, subjects with self-reported low ability to imagine displayed no difference in activation compared to those with high imagery ability. CONCLUSIONS: These findings are consistent with other works demonstrating primarily ipsilateral control of the hemiparetic hand in subjects with functional movement and lay the groundwork for further investigation into the ability of mental imagery to affect functionally relevant cortical control in subjects recovering from stroke.