Fig. 10

Typical and dark astrocytes in human post-mortem brain samples. Representative 5 nm per pixel of resolution scanning electron microscopy images of a typical (in A) and dark astrocytes (B, C) in the hippocampal head of an aged female (81-year-old, cause of death—asphyxia, post-mortem delay of 18 h). In A, a typical astrocyte interacts with several axon terminals (pseudo-colored in orange) and myelinated axons (pseudo-colored in yellow). The astrocyte possesses several fully digested phagosomes (pseudo-colored in pink) and altered mitochondria (pseudo-colored in blue). In B a dark astrocyte with several angular processes is making direct contacts with axon terminals (pseudo-colored in orange) and displaying several signs of cellular stress such as altered mitochondria (pseudo-colored in blue) and dilated endoplasmic reticulum (pseudo-colored in purple). In C a dark astrocytic process interacts with axon terminals (pseudo-colored in orange) and dendritic spine (pseudo-colored in green). The dark process contains several fully digested phagosomes (pseudo-colored in pink), altered mitochondria (pseudo-colored in blue), and healthy mitochondria (pseudo-colored in red). Yellow outline = nuclear membrane, green outline = typical astrocytic cytoplasm, purple outline = dark astrocytic cytoplasm, yellow pseudo-coloring = myelinated axons, orange pseudo-coloring = axon terminals, green pseudo-coloring = dendritic spines, blue pseudo-coloring = altered mitochondria, red pseudo-coloring = non-altered mitochondria, pink pseudo-coloring = fully digested phagosomes, purple pseudo-coloring = dilated endoplasmic reticulum