scholarly journals Small vessel disease, neurovascular regulation and cognitive impairment: post-mortem studies reveal a complex relationship, still poorly understood

2017 ◽  
Vol 131 (14) ◽  
pp. 1579-1589 ◽  
Author(s):  
Seth Love ◽  
J. Scott Miners

The contribution of vascular disease to cognitive impairment is under-recognized and the pathogenesis is poorly understood. This information gap has multiple causes, including a lack of post-mortem validation of clinical diagnoses of vascular cognitive impairment (VCI) or vascular dementia (VaD), the exclusion of cases with concomitant neurodegenerative disease when diagnosing VCI/VaD, and a lack of standardization of neuropathological assessment protocols for vascular disease. Other contributors include a focus on end-stage destructive lesions to the exclusion of more subtle types of diffuse brain injury, on structural abnormalities of arteries and arterioles to the exclusion of non-structural abnormalities and capillary damage, and the use of post-mortem sampling strategies that are biased towards the identification of neurodegenerative pathologies. Recent studies have demonstrated the value of detailed neuropathology in characterizing vascular contributions to cognitive impairment (e.g. in diabetes), and highlight the importance of diffuse white matter changes, capillary damage and vasoregulatory abnormalities in VCI/VaD. The use of standardized, evidence-based post-mortem assessment protocols and the inclusion of biochemical as well as morphological methods in neuropathological studies should improve the accuracy of determination of the contribution of vascular disease to cognitive impairment and clarify the relative contribution of different pathogenic processes to the tissue damage.

2015 ◽  
Vol 36 (1) ◽  
pp. 55-71 ◽  
Author(s):  
A Vilar-Bergua ◽  
I Riba-Llena ◽  
C Nafría ◽  
A Bustamante ◽  
V Llombart ◽  
...  

Vascular dementia is the second most common type of dementia after Alzheimer’s disease (AD). Subcortical ischemic vascular disease refers to a form of vascular cognitive impairment characterized by the presence of diffuse white matter hyperintensities (WMHs) and multiple lacunar infarcts. These neuroimaging findings are mainly caused by cerebral small-vessel disease (cSVD) and relate to aging and cognitive impairment, but they can also be silent and highly prevalent in otherwise healthy individuals. We aimed to review studies on blood and cerebrospinal fluid (CSF) markers related to the presence of WMHs and lacunar infarcts that have been conducted in the past in large population-based studies and in high-risk selected patients (such as those with vascular risk factors, vascular cognitive impairment, or AD). Relevant associations with the presence and progression of cSVD have been described in the blood for markers related to inflammatory processes, endothelial damage and coagulation/fibrinolysis processes, etc. Also, different combinations of CSF markers might help to differentiate between etiologic types of dementia. In the future, to translate these findings into clinical practice and use biomarkers to early diagnosis and monitoring vascular cognitive impairment would require the replication of candidate markers in large-scale, multicenter, and prospectively designed studies.


Stroke ◽  
2012 ◽  
Vol 43 (suppl_1) ◽  
Author(s):  
Gary A Rosenberg ◽  
Jillian Prestopnik ◽  
Jeffrey Thompson ◽  
Charles Gasparovic ◽  
Branko N Huisa-Garate ◽  
...  

Introduction: Vascular cognitive impairment (VCI) and Alzheimer’s disease (AD) have a high degree of overlap in a number of large autopsy series. However, few studies have examined the overlap during life. VCI is a heterogeneous disorder due to large and small vessel vascular disease (SVD). Biomarkers of inflammation are present in the SVD, which is a progressive form of VCI that is characterized by MRI findings of lacunar strokes and white matter hyperintensities (WMHs), executive dysfunction, focal neurological findings, apathy, urinary problems and gait imbalance. Recently, we showed an association between a reduced matrix metalloproteinase-2 (MMP-2) CSF index and disruption of the blood-brain barrier (BBB) in SVD. We hypothesized that patients with both VCI and AD would show CSF and MRI biomarkers for both diseases. Patients and Methods: Patients (N=60) with VCI underwent neurological and neuropsychological testing. MRI was done with FLAIR, proton magnetic resonance spectroscopy (1H-MRS) to measure ischemia with N-acetylaspartate (NAA), and dynamic contrast-enhanced MRI (DCEMRI) to measure BBB transfer constants (K i ). CSF (N=37) was obtained by lumbar puncture for measurements of albumin index, MMP-2 and MMP-9 indexes, ABeta 1-42, total-tau (T-Tau) and hyperphosphorylated-tau (P-Tau). Results: BD patients had large WMHs, while large vessel (multi-infarct and single strategic stroke) patients had small WMHs. NAA was used as a biomarker of lesion size due to ischemic damage in the white matter. ROC plots showed that a NAA cut-point of 12 separated patients with large WMHs (low NAA) from small WMHs (p<0.0001). K i transfer constants above 0.0018 (ROC; p<0.0001) and MMP-2 below 0.0099 (ROC; p<0.0001) were considered abnormal. SVD patients had reduced ABeta 1-42 compared to control CSF. P-Tau was unaffected. Abnormal values for K i and MMP-2 index were present in both large and small vessel disease patients. Conclusions: Our results show that SVD patients have significantly reduced levels of ABeta 1-42 in CSF, suggesting impairment in amyloid metabolism associated with vascular disease. These findings conform to the autopsy findings and suggest that multimodal biomarkers may provide information during life about the presence of both AD and VCI.


2017 ◽  
Vol 131 (6) ◽  
pp. 425-437 ◽  
Author(s):  
Gary A. Rosenberg

Vascular cognitive impairment and dementia (VCID) include a wide spectrum of chronic manifestations of vascular disease related to large vessel strokes and small vessel disease (SVD). Lacunar strokes and white matter (WM) injury are consequences of SVD. The main vascular risk factor for SVD is brain hypoperfusion from cerebral blood vessel narrowing due to chronic hypertension. The hypoperfusion leads to activation and degeneration of astrocytes with the resulting fibrosis of the extracellular matrix (ECM). Elasticity is lost in fibrotic cerebral vessels, reducing the response of stiffened blood vessels in times of increased metabolic need. Intermittent hypoxia/ischaemia activates a molecular injury cascade, producing an incomplete infarction that is most damaging to the deep WM, which is a watershed region for cerebral blood flow. Neuroinflammation caused by hypoxia activates microglia/macrophages to release proteases and free radicals that perpetuate the damage over time to molecules in the ECM and the neurovascular unit (NVU). Matrix metalloproteinases (MMPs) secreted in an attempt to remodel the blood vessel wall have the undesired consequences of opening the blood–brain barrier (BBB) and attacking myelinated fibres. This dual effect of the MMPs causes vasogenic oedema in WM and vascular demyelination, which are the hallmarks of the subcortical ischaemic vascular disease (SIVD), which is the SVD form of VCID also called Binswanger's disease (BD). Unravelling the complex pathophysiology of the WM injury-related inflammation in the small vessel form of VCID could lead to novel therapeutic strategies to reduce damage to the ECM, preventing the progressive damage to the WM.


Brain ◽  
2020 ◽  
Vol 143 (10) ◽  
pp. 2998-3012
Author(s):  
Ruth Geraldes ◽  
Margaret M Esiri ◽  
Rafael Perera ◽  
Sydney A Yee ◽  
Damian Jenkins ◽  
...  

Abstract Vascular comorbidities have a deleterious impact on multiple sclerosis clinical outcomes but it is unclear whether this is mediated by an excess of extracranial vascular disease (i.e. atherosclerosis) and/or of cerebral small vessel disease or worse multiple sclerosis pathology. To address these questions, a study using a unique post-mortem cohort wherein whole body autopsy reports and brain tissue were available for interrogation was established. Whole body autopsy reports were used to develop a global score of systemic vascular disease that included aorta and coronary artery atheroma, cardiac hypertensive disease, myocardial infarction and ischaemic stroke. The score was applied to 85 multiple sclerosis cases (46 females, age range 39 to 84 years, median 62.0 years) and 68 control cases. Post-mortem brain material from a subset of the multiple sclerosis (n = 42; age range 39–84 years, median 61.5 years) and control (n = 39) cases was selected for detailed neuropathological study. For each case, formalin-fixed paraffin-embedded tissue from the frontal and occipital white matter, basal ganglia and pons was used to obtain a global cerebral small vessel disease score that captured the presence and/or severity of arteriolosclerosis, periarteriolar space dilatation, haemosiderin leakage, microinfarcts, and microbleeds. The extent of multiple sclerosis-related pathology (focal demyelination and inflammation) was characterized in the multiple sclerosis cases. Regression models were used to investigate the influence of disease status on systemic vascular disease and cerebral small vessel disease scores and, in the multiple sclerosis group, the relationship between multiple sclerosis-related pathology and both vascular scores. We show that: (i) systemic cardiovascular burden, and specifically atherosclerosis, is lower and cerebral small vessel disease is higher in multiple sclerosis cases that die at younger ages compared with control subjects; (ii) the association between systemic vascular disease and cerebral small vessel disease is stronger in patients with multiple sclerosis compared with control subjects; and (iii) periarteriolar changes, including periarteriolar space dilatation, haemosiderin deposition and inflammation, are key features of multiple sclerosis pathology outside the classic demyelinating lesion. Our data argue against a common primary trigger for atherosclerosis and multiple sclerosis but suggest that an excess burden of cerebral small vessel disease in multiple sclerosis may explain the link between vascular comorbidity and accelerated irreversibility disability.


2011 ◽  
Vol 40 (2) ◽  
pp. 175-180 ◽  
Author(s):  
C. Ramos-Estebanez ◽  
I. Moral-Arce ◽  
A. Gonzalez-Mandly ◽  
V. Dhagubatti ◽  
J. Gonzalez-Macias ◽  
...  

Author(s):  
K.D. Langdon ◽  
C. Cordova ◽  
S. Granter-Button ◽  
J. Boyd ◽  
J. Peeling ◽  
...  

Most basic science research has focused on overt stroke caused by blockage of major blood vessels. Less attention has been paid to small vessel disease giving rise to covert stroke that often leads to vascular cognitive impairment (VCI). One reason for this may be the relative lack of relevant animal models. This talk will describe a model of VCI induced in middle-aged Sprague-Dawley rats exposed to a diet high in saturated fats, salt and refined sugar (HFSS). In Experiment 1, rats fed HFSS and subjected to a small mediodorsal (MD) thalamic stroke with or without concomitant cerebral hypoperfusion experienced significant executive dysfunction. In Experiment 2, dietary influences on functional, physiological and anatomical parameters were assessed. We found significant hypertension, blockage of brain microvessels (2-photon microscopy) and white matter atrophy in HFSS diet animals. As in Experiment 1, profound, specific set-shifting executive dysfunction was noted following both small MD infarcts (0.332 mm3) and the HFSS diet. In summary, these data describe a middle-aged animal model of VCI that includes clinically-relevant metabolic disturbances and small vessel disease and as such may be helpful in developing new cognitive therapies.


2019 ◽  
Vol 28 (8) ◽  
pp. 1009-1017 ◽  
Author(s):  
Li Gong ◽  
Xiangzhu Tian ◽  
Jing Zhou ◽  
Qiong Dong ◽  
Yan Tan ◽  
...  

As a putative marker of cerebral small vessel disease, cerebral microbleeds (CMBs) have been associated with vascular cognitive impairment. Both iron accumulation and amyloid protein precursor (APP) dysregulation are recognized as pathological hallmarks underlying the progression of CMBs, but their cross-talk is not yet understood. In this study, we found a profound increase of amyloid formation with increasing FeCl3 treatment, and a distinct change in APP metabolism and expression of iron homeostasis proteins (ferritin, Fpn1, iron regulatory protein) was observed at the 300 uM concentration of FeCl3. Further results revealed that extracellular iron accumulation might potentially induce binding of APP to BACE1 for amyloid formation and decrease the capability of APP/Fpn1 in mediating iron export. Our findings in this study, reflecting a probable relationship between iron dyshomeostasis and amyloid pathology, may help shed light on the underlying pathogenesis of CMBs in vascular cognitive impairment.


Sign in / Sign up

Export Citation Format

Share Document