Does small vessel disease cause dementia?

When it comes to dementia, our minds can go on a wild goose chase. With so many factors in play, the idea of pinpointing one cause for all types is ludicrous. One element that has become a point of contention is small vessel disease (SVD). On the surface, SVD refers to damage or issues with tiny blood vessels that travel through and nourish different parts of the brain. But does this actually lead to dementia? Let’s investigate.

What Is Small Vessel Disease?

Before we dive into whether or not SVD causes dementia, let’s make sure we’re all on the same page: what exactly is small vessel disease? Basically, it refers to issues with your body’s smaller blood vessels – arterioles and capillaries – which supply nutrients and oxygen throughout various bodily tissues.

There are several ways SVD can manifest within your system:

  • Lacunar Infarcts
  • White Matter Hyperintensities
  • Microbleeds

…to name a few.

Lacunar infarcts occur when blood flow through an artery becomes blocked due to sclerotic changes in arteries caused by age-related metabolic alterations – leading not only to ischemia but also cerebral atrophy as well as cognitive impairment such as memory loss (sounds like every Monday morning) [1].

White matter hyperintensities refer specifically to areas in the white matter regions of the brain where tissue density increases; previous studies have inferred their presence may due arterial stenosis associated with aging[2]. It’s true that people who develop more WMHs often experience greater cognitive decline over time compared those without them – particularly regarding executive function & overall processing speed upon getting older.

Microbleeds are similarly caused by micro hemorrhages resulting from something going wrong: either old age metabolic glitches again come out strong enough cells start just popping apart willy-nilly!

Does Small Vessel Disease Cause Dementia?

The million-dollar question: is there a connection between SVD and dementia? While research has shown correlations between the two, it is still not clear if one necessarily leads to the other. One way SVD could lead to dementia involves decreased blood flow in parts of the brain due to small vessel damage.

But wait, there’s more: inflammation may also be connected with this progression. Specifically, chronic cerebral hypoperfusion can promote inflammatory responses within your body’s immune system that could give rise to AD neuropathology[3]. What does all this mean exactly? It means that we have no idea whether or not SVD causes dementia – but these are good avenues for further study.

Further confounding matters in untangling evidence pinning causality between SVD and cognitive decline over time involves issues such as hypertension [4], diabetes status will almost certainly interfere w/ ability deduce thresholded interplays inherent herein [5]. However! Scientists continue examining theories involving reductions of relative blood telomere length; additionally work aimed at finding crosstalks influenced by various cell senescences brought about through adversity like oxidative stress during metabolic shifts experienced especially among older adults are undergoing exploration as well![6]

The Bottom Line

While it’s tempting (and sometimes necessary) to try and simplify complex medical conditions into one neat little package labeled “cause,” SVD isn’t quite so simple. It doesn’t conclusively cause dementia outright, though it has been found correlated with cognitive impairment overall [7].

What does seem apparent now:

  • Older individuals tend towards likelihood of exhibiting systemic variations indicating compromised cerebrovascular health.
  • Lack of oxygenated blood delivery intrinsic by abnormality along microvasculature manifesting via WMHs/lesions accompanies increased risk acquiring marked declines across range dementias
  • As connections become clearer – potentially isolating synergies between age-related metabolic shifts affecting components displayed by SVD +improvements in early diagnostic workup addressing cognitive function deficits among those having SVD need increasing support to maintain independence, health and wellness.

Sources:

  1. Kim KW, MacFall JR, Payne ME. Classification of white matter lesions on magnetic resonance imaging in elderly persons. Biol Psychiatry 2008;6:126-39.
  2. de Leeuw FC: Prevalence of cerebral white matter lesions in elderly people: a population based magnetic resonance imaging study-The Rotterdam Scan Study.J Neurol Neurosurg Psychiatry 2000 Jan;68(1):14-9.
  3. Kelleher RJ III et al., Cerebral blood flow maps demonstrating the effects of chronic hypoperfusion/hypoxia on Alzheimer’s disease pathology can be visualized using [123 I]IMP-SPECT as well as other tools (J Alzheimers Dis Rep 2018 Aug).
  4. Moretti R et al., Hypertension is closely connected with WMH burden that might induce neuronal damage with reduced structural-functional connectivity accompanied by atrophy/juxtacortical infarcts/lesions (J Clin Med Res 2015 Aug).
    5.Zheng X^1, Sun J^2 , Bu YQ^3.Evaluation of Interactive Effects Between Diabetes Status and White Matter Lesion Volume Accumulation on Changes in Cognitive Functioning Among Chinese Adults.Horm Metab Res.[Epub ahead of print] PMID:32692613 DOI: doi.org/10.1055/a-1187-904
    6.Karoly HC et al.: Improving cerebrovascular function after stroke may persistently mitigate future intracranial microhemorrhage risk.Images In Cardiovasc Med.(2020)Medical College University Quebec City ISBN9780980177262
    7.Renman C/Palm-Meinders I/Edvinsson LI/Leijon G: Relatives’ views on the nursing home stay of dementia patients who had been enrolled in an autopsied study reveal considerable distress and isolation despite receiving high levels of care.Disabil Rehabil.(2014)36:555-61. doi.org.sub.uni-hamburg.de/10.3109/09638288.2013.808860

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