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

Topic: Brain proteins, microglia and lab models

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

Key findings

• Even though in vivo imaging studies document significant reductions of hippocampal volume in depressed patients, the exact underlying cellular mechanisms are unclear.
• Since stressful life events are associated with an increased risk of developing depression, preclinical studies in which animals are exposed to chronic stress have been used to understand the hippocampal shrinkage in depressed patients.
• We conclude that mainly other factors, like alterations in the somatodendritic, axonal, and synaptic components and putative glial changes are most likely to explain the hippocampal shrinkage in depression, while shifts in fluid balance or changes in the extracellular space cannot be excluded either.

Study details

• Evidence strengthLow

Read the original

• DOI: 10.1007/s00406-007-0728-0
• PubMed: 17401728
• Original source →

Free copy unknown: no free-copy check has an answer for this record yet. That does not mean it is paywalled.

@article{czeh2007-17401728,
  author  = {Czéh, B. and Lucassen, P. J.},
  title   = {{What causes the hippocampal volume decrease in depression? Are neurogenesis, glial changes and apoptosis implicated?}},
  journal = {European archives of psychiatry and clinical neuroscience},
  year    = {2007},
  doi     = {10.1007/s00406-007-0728-0},
  pmid    = {17401728},
  url     = {https://doi.org/10.1007/s00406-007-0728-0}
}

Related studies in Hippocampus size on brain scans

• Chronic brain hypoperfusion causes early glial activation and neuronal death, and subsequent long-term memory impairment Brain research bulletin · 2011-10-21 · usefulness score 36/100
• Prolactin prevents chronic stress-induced decrease of adult hippocampal neurogenesis and promotes neuronal fate The Journal of neuroscience : the official journal of the Society for Neuroscience · 2009-02-01 · usefulness score 36/100
• The effects of chronic glucocorticoid exposure on dendritic length, synapse numbers and glial volume in animal models: implications for hippocampal volume reductions in depression Physiology & behavior · 2009-09-26 · usefulness score 36/100
• Sleep deprivation and hippocampal vulnerability: changes in neuronal plasticity, neurogenesis and cognitive function Neuroscience · 2015-04-29 · usefulness score 36/100
• Hippocampal changes associated with early-life adversity and vulnerability to depression Biological psychiatry · 2009-12-16 · usefulness score 52/100
• State-dependent changes in hippocampal grey matter in depression Molecular psychiatry · 2012-11-06 · usefulness score 50/100

Similar studies

• Decreased hippocampal volume in healthy girls at risk of depression 2010 · Hippocampus size on brain scans
• Reduced hippocampal volume correlates with executive dysfunctioning in major depression 2006 · Hippocampus size on brain scans
• Hippocampal volume change in depression: late- and early-onset illness compared 2004 · Hippocampus size on brain scans
• Hippocampal volume reduction in major depression 2000 · Hippocampus size on brain scans
• Enlarged amygdala volume and reduced hippocampal volume in young women with major depression 2004 · Hippocampus size on brain scans
• Depression duration but not age predicts hippocampal volume loss in medically healthy women with recurrent major depression 1999 · Hippocampus size on brain scans

More on Hippocampus size on brain scans

• A review that covers this ground Implications of adult hippocampal neurogenesis in antidepressant action Journal of psychiatry & neuroscience : JPN · 2004-05-01 · usefulness score 36/100
• Newest in this subject Biomarker Changes during 20 Years Preceding Alzheimer's Disease The New England journal of medicine · 2024-02-01 · Peer-reviewed · usefulness score 69/100
• Newest in this subject Clinical safety and efficacy of allogenic human adipose mesenchymal stromal cells-derived exosomes in patients with mild to moderate Alzheimer's disease: a phase I/II clinical trial General psychiatry · 2023-10-11 · Peer-reviewed · usefulness score 43/100

See all studies in Hippocampus size on brain scans →