The Structure of the Spinal Cord Ependymal Region in Adult Humans Is a Distinctive Trait among Mammals

The ependymal region, important for spinal cord regeneration in some animals, changes significantly in humans after childhood, losing the central canal. This study explores this unique human trait by comparing it to other mammals, including the Naked Mole-Rat (NMR) and a mutant mouse strain (hyh) that also lack a central canal. Researchers found that while NMR and hyh mice also lose their central canal, the tissue that replaces it is structurally different from that found in humans. This suggests that the mechanism of central canal closure and the resulting tissue organization is specific to humans. The study also provides new insights into how the human central canal closes, suggesting it involves a process called epithelial to mesenchymal transition (EMT), where ependymal cells lose their original structure and transform into a different cell type.

• 1
  Adult humans uniquely lose the central canal, which is replaced by a structure with large ependymal cell accumulations, astrogliosis, and perivascular pseudo-rosettes, unlike other mammals.
• 2
  Naked Mole-Rats and hyh mice also lack a central canal, but the substituting tissue is different from that in humans, resembling normal lamina X without large cell accumulations or gliosis.
• 3
  Central canal closure in humans potentially involves delamination of the ependymal epithelium, apical polarity loss, and expression of EMT signaling mediators.