White matter degeneration in vascular and other ageing-related dementias.
Level 5 - mechanism / opinion, no new human data
Narrative review of pathophysiology, imaging, and preclinical models without systematic search or meta-analysis.
PubMed 29210074 · doi:10.1111/jnc.14271
What was done
This review synthesized neuroimaging characteristics, cellular pathology, and preclinical models related to white matter degeneration in vascular dementia and Alzheimer's disease. The authors examined pathological substrates—including leukoaraiosis and magnetic resonance imaging white matter hyperintensities—cellular disruption within the gliovascular unit (astrocytes, oligodendrocytes, microglia, pericytes), hemodynamic mechanisms of deep white matter chronic hypoxia, and pharmacological compounds tested to mitigate blood-brain barrier damage, oxidative stress, and inflammation.
What was found
The abstract provides no quantitative data or effect sizes. Key qualitative pathological alterations described include myelin loss, axonal abnormalities, arteriolosclerosis, lacunar infarcts, microbleeds, and dilated perivascular spaces. At the cellular level, early changes involve oligodendrocyte loss and astrocytic clasmatodendrosis accompanied by aquaporin 4 displacement, which precede microvascular degeneration, blood-brain barrier leakage, and deep white matter edema. Preclinical testing of various compounds yielded variable efficacy, leading the authors to conclude that single-target therapies are insufficient to address the multiple substrates of white matter degeneration.
Why it matters
The review emphasizes that white matter damage across age-related dementias is not driven by a single pathway but reflects complex failure of the gliovascular unit under chronic hypoperfusion. This framework indicates that preserving cognitive function in vascular and mixed dementias will require multimodal or combination therapeutic strategies.
Limits
This is a narrative review that does not report systematic search methods, screening criteria, or quantitative data synthesis. Specific animal models, drug classes, dosages, and human clinical trial outcomes are not detailed in the abstract, preventing independent evaluation of comparative drug efficacy or clinical translation.
Cited by
- supports White matter hyperintensities are associated with blood-brain barrier leakage, pericyte detachment, and leakage of blood toxins that damage myelin sheaths and axons.