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Figure 2 Photomicrographs of early neointima formation, focused on the luminal surface region. (A) Palisade-like alignment of single cells (arrows) along the internal elastic lamina (IEL) at day 4 (trichrome staining). (B) Strong cell-bound OX-62 signaling restricted to early neointima contrasts to unlabeled media at day 7. (C) Magnified detail of neointima at day 7 demonstrating consistent colocalization of OX-62 (dark blue) and S100 (red) in neointimal dendritic cells (DC) (no nuclear counterstaining). (D) Transmission electron microscopy identification of two DCs extending along the IEL at day 7. Note their long dendritic processes and veils, the lobed nucleus, and prominent tubulovesicular network. (E) Transmission electron microscopy detection of apoptosis located in basal neointima close to IEL. Apoptotic shrinkage and detached anchorage from surrounding extracellular matrix are indicated by condensed cytoplasm and pericellular region markedly less dense than adjacent matrix. (F) Representative hyperplastic neointima at day 28. Note the distinct residual OX-62 labeling along the luminal surface, while the vast majority of cells located in basal regions are negative. (G) Transmission electron microscopy image of representative hyperplastic neointima at day 28 that predominantly comprises cells with SMC appearance and apparently shows no apoptosis. Luminal neointima reveals perpendicular alignment of the cells and loose extracellular matrix compared with basal regions. (H) Intense -smooth muscle actin immunoreactivity of the neointima and weak staining of medial SMCs at day 28. Bar = 30 µm (A to C, F to H); bar = 5 µm (D, E).