Endothelial Dysfunction and Hyperhomocysteinemia-Linked Cerebral Small Vessel Disease: Underlying Mechanisms and Treatment Timing

Cerebral small vessel disease (cSVD)—a common cause of stroke and vascular dementia—is a group of clinical syndromes that affects the brain's small vessels, including arterioles, capillaries, and venules. Its pathogenesis is not fully understood, and effective treatments are limited. Increasing evidence indicates that an elevated total serum homocysteine level is directly and indirectly associated with cSVD, and endothelial dysfunction plays an active role in this association. Hyperhomocysteinemia affects endothelial function through oxidative stress, inflammatory pathways, and epigenetic alterations at an early stage, even before the onset of small vessel injuries and the disease. Therefore, hyperhomocysteinemia is potentially an important therapeutic target for cSVD. However, decreasing the homocysteine level is not sufficiently effective, possibly due to delayed treatment, which underlying reason remains unclear. In this review, we examined endothelial dysfunction to understand the close relationship between hyperhomocysteinemia and cSVD and identify the optimal timing for the therapy.

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Circulating biologic markers of endothelial dysfunction in cerebral small vessel disease: A review

Journal of Cerebral Blood Flow & Metabolism ◽

10.1038/jcbfm.2015.116 ◽

2015 ◽

Vol 36 (1) ◽

pp. 72-94 ◽

Cited By ~ 98

Author(s):

Anna Poggesi ◽

Marco Pasi ◽

Francesca Pescini ◽

Leonardo Pantoni ◽

Domenico Inzitari

Keyword(s):

Endothelial Dysfunction ◽

Endothelial Function ◽

Small Vessel Disease ◽

Brain Magnetic Resonance Imaging ◽

Cerebral Small Vessel Disease ◽

Small Vessel ◽

Perivascular Spaces ◽

Vessel Disease ◽

Brain Changes

The term cerebral small vessel disease (SVD) refers to a group of pathologic processes with various etiologies that affect small arteries, arterioles, venules, and capillaries of the brain. Magnetic resonance imaging (MRI) correlates of SVD are lacunes, recent small subcortical infarcts, white-matter hyperintensities, enlarged perivascular spaces, microbleeds, and brain atrophy. Endothelial dysfunction is thought to have a role in the mechanisms leading to SVD-related brain changes, and the study of endothelial dysfunction has been proposed as an important step for a better comprehension of cerebral SVD. Among available methods to assess endothelial function in vivo, measurement of molecules of endothelial origin in peripheral blood is currently receiving selective attention. These molecules include products of endothelial cells that change when the endothelium is activated, as well as molecules that reflect endothelial damage and repair. This review examines the main molecular factors involved in both endothelial function and dysfunction, and the evidence linking endothelial dysfunction with cerebral SVD, and gives an overview of clinical studies that have investigated the possible association between endothelial circulating biomarkers and SVD-related brain changes.

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Role of Purinergic Signalling in Endothelial Dysfunction and Thrombo-Inflammation in Ischaemic Stroke and Cerebral Small Vessel Disease

Biomolecules ◽

10.3390/biom11070994 ◽

2021 ◽

Vol 11 (7) ◽

pp. 994

Author(s):

Natasha Ting Lee ◽

Lin Kooi Ong ◽

Prajwal Gyawali ◽

Che Mohd Nasril Che Mohd Nassir ◽

Muzaimi Mustapha ◽

...

Keyword(s):

Oxidative Stress ◽

Endothelial Dysfunction ◽

Inflammatory Response ◽

Small Vessel Disease ◽

Ischemia Reperfusion ◽

Cerebral Small Vessel Disease ◽

Small Vessel ◽

Purinergic Signalling ◽

Vessel Disease ◽

The Brain

The cerebral endothelium is an active interface between blood and the central nervous system. In addition to being a physical barrier between the blood and the brain, the endothelium also actively regulates metabolic homeostasis, vascular tone and permeability, coagulation, and movement of immune cells. Being part of the blood–brain barrier, endothelial cells of the brain have specialized morphology, physiology, and phenotypes due to their unique microenvironment. Known cardiovascular risk factors facilitate cerebral endothelial dysfunction, leading to impaired vasodilation, an aggravated inflammatory response, as well as increased oxidative stress and vascular proliferation. This culminates in the thrombo-inflammatory response, an underlying cause of ischemic stroke and cerebral small vessel disease (CSVD). These events are further exacerbated when blood flow is returned to the brain after a period of ischemia, a phenomenon termed ischemia-reperfusion injury. Purinergic signaling is an endogenous molecular pathway in which the enzymes CD39 and CD73 catabolize extracellular adenosine triphosphate (eATP) to adenosine. After ischemia and CSVD, eATP is released from dying neurons as a damage molecule, triggering thrombosis and inflammation. In contrast, adenosine is anti-thrombotic, protects against oxidative stress, and suppresses the immune response. Evidently, therapies that promote adenosine generation or boost CD39 activity at the site of endothelial injury have promising benefits in the context of atherothrombotic stroke and can be extended to current CSVD known pathomechanisms. Here, we have reviewed the rationale and benefits of CD39 and CD39 therapies to treat endothelial dysfunction in the brain.

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Abstract TMP119: High Homocysteine Level is not Associated With White Matter Changes, Dementia nor Mortality After Ischemic Stroke

Stroke ◽

10.1161/str.47.suppl_1.tmp119 ◽

2016 ◽

Vol 47 (suppl_1) ◽

Author(s):

Susanna Melkas ◽

Sami Curtze ◽

Gerli Sibolt ◽

Niku K Oksala ◽

Jukka Putaala ◽

...

Keyword(s):

Ischemic Stroke ◽

White Matter ◽

Homocysteine Level ◽

Small Vessel Disease ◽

Cerebral Small Vessel Disease ◽

Small Vessel ◽

Cross Sectional ◽

White Matter Changes ◽

Vessel Disease

Background: Association between high homocysteine level and cerebral small-vessel disease has been implicated in cross-sectional studies, but results from longitudinal studies have been less clear. The aim of this study was to investigate whether homocysteine level at 3-months poststroke relates to the occurrence of white matter changes (WMC), the surrogate of cerebral small-vessel disease. We also investigated whether it relates to the prognosis after ischemic stroke regarding the risk of dementia at 3-months and mortality in long-term follow-up. Methods: A total of 321 consecutive acute ischemic stroke patients aged 55 to 85 were included in the study and followed up to 12 years. Plasma homocysteine level and occurrence of WMC in MRI were measured 3 months poststroke and dementia according to DSM-III was evaluated at the same time. Findings: The median homocysteine level was 13.50 μmol/l (interquartile range [IQR] 10.60-18.50 μmol/l). Total of 81 patients (25.2%) had homocysteine level above 18.50 μmol/l. In logistic regression analysis, homocysteine level above 18.50 μmol/l was not associated with severe WMC nor with dementia at 3 months poststroke. In Kaplan-Meier analysis, homocysteine level above 18.50 μmol/l was not associated with survival in 12-year follow-up. For further analysis, the group was divided in quartiles according to homocysteine level. The quartiles did not differ in occurrence of severe WMC at baseline, in the risk of dementia at 3 months, nor in the risk of mortality in 12-year follow-up. Interpretation: In our poststroke cohort homocysteine level is not associated with WMC. Further, it does not relate to impaired prognosis manifested as dementia at 3 months or mortality in 12-year follow-up.

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