What causes the hippocampal volume decrease in depression? Are neurogenesis, glial changes and apoptosis implicated?

摘要: Even though in vivo imaging studies document significant reductions of hippocampal volume depressed patients, the exact underlying cellular mechanisms are unclear. Since stressful life events associated with an increased risk developing depression, preclinical which animals exposed to chronic stress have been used understand shrinkage patients. Based on morphometrical these models, parameters like dendritic retraction, suppressed adult neurogenesis and neuronal death, all due elevated levels glucocorticoids, suggested as major causative factors shrinkage. However, histopathological examining hippocampi individuals so far failed confirm either a massive loss or suppression dentate neurogenesis, event that is notably very rare elderly humans. In fact, many structural changes reduction appear be reversible. Clearly, more needed; especially ones (a) employ stereological quantification, (b) focus specific elements populations, (c) performed nonmedicated We conclude mainly other factors, alterations somatodendritic, axonal, synaptic components putative glial most likely explain while shifts fluid balance extracellular space cannot excluded either.