The relationship between diabetes-related cognitive dysfunction and leukoaraiosis

Cognitive dysfunction is a degenerative disease of the central nervous system, which often associates with ageing brain as well as neurodegenerative diseases. A growing body of evidence suggests that patients with diabetes mellitus (DM) have a significantly higher risk of cognitive impairment. In recent years, studies have found that patients with diabetes-related cognitive dysfunction have an increased burden of leukoaraiosis (LA), and larger white matter hyperintensity (WMH) volume. With the recent advancement of technologies, multimodal imaging is widely exploited for the precise evaluation of central nervous system diseases. Emerging studies suggest that LA pathology can be used as a predictive signal of white matter lesions in patients with diabetes-related cognitive dysfunction, providing support for early identification and diagnosis of disease. This article reviews the findings, epidemiological characteristics, pathogenesis, imaging features, prevention and treatment of LA pathophysiology in patients with diabetes-related cognitive dysfunction.

Systemic oxidative stress and cognitive function in Parkinson's disease with different PWMH or DWMH lesions

BACKGROUND

Parkinson's disease (PD), frequently accompanied by cognitive impairments, is associated with systemic oxidative stress and abnormal structural changes on brain images. We aimed to identify the correlation between systemic oxidative stress and cognitive function in PD patients with different periventricular white matter hyperintensities (PWMH) and deep white matter hyperintensities (DWMH).

METHODS

A total of 146 participants with idiopathic PD underwent brain MRI, which revealed PWMH and DWMH. The number of lesions were evaluated using the Fazekas criteria. Systemic oxidative stress was determined as early or late phase changes in leukocyte apoptosis and its subsets by flow cytometry. Cognitive functions, including attention, executive function, memory, language, and visual space, were assessed.

RESULTS

For different DWMH, the leukocyte apoptosis and its subsets were significantly different.. However, there were no significant differences in oxidative stress biomarkers in PD patients with different PWMH. Attention and memory were significantly decreased in patients with more advanced DWMH injuries. Attention, memory, and language were significantly impaired in patients with worse PWMH lesions.

CONCLUSION

Significant oxidative stress biomarker alternations in PD patients with DWMH, but not PWMH, might be associated with white matter injury. Systemic inflammatory responses may contribute to deep white matter damage in PD. Further, more cognitive deficits were seen in PD patients with worse deep white matter lesions, especially in moderate to severe periventricular white matter injury.

TRIAL REGISTRATION

Retrospective study.

Dietary Inflammatory Index and Leukoaraiosis in Patients with Ischemic Stroke

OBJECTIVES

Diet may change the chronic levels of systemic inflammation, which in turn influence the development of leukoaraiosis (LA). This study aimed to examine the association between dietary inflammatory index (DII) and LA in patients with ischemic stroke.

METHODS

Patients with first-ever ischemic stroke were enrolled from two centers. A semi-quantitative food frequency questionnaire (FFQ) was used to evaluate diet contents. The DII score of each patient was calculated based on the reported diet contents. Presence and degree of LA were evaluated with a magnetic resonance imaging (MRI) scan. LA was graded according to Fazekas scale.

RESULTS

Of the 497 enrolled patients, 337 (67.8%) were detected with LA. Patients with LA had a higher DII score (0.23 vs -0.88, P < 0.001). Logistic regression analysis detected that patients with highest quartile of DII score had an OR of 3.61 (95% CI: 2.05-6.36, P < 0.001) for LA compared with those with lowest quartile of DII. After adjusting for major confounders, the highest DII quartile remained as an independent predictor for LA (OR = 2.66, 95% CI: 1.41-5.00, P = 0.008).

CONCLUSIONS

A pro-inflammatory diet pattern, as indicated by higher DII values, appears to be associated with a higher risk of LA. This result suggested that dietary-mediated inflammation may involved in the pathogenesis of LA, which warrant further study.

Rapid Automated Quantification of Cerebral Leukoaraiosis on CT Images: A Multicenter Validation Study

Purpose To validate a random forest method for segmenting cerebral white matter lesions (WMLs) on computed tomographic (CT) images in a multicenter cohort of patients with acute ischemic stroke, by comparison with fluid-attenuated recovery (FLAIR) magnetic resonance (MR) images and expert consensus. Materials and Methods A retrospective sample of 1082 acute ischemic stroke cases was obtained that was composed of unselected patients who were treated with thrombolysis or who were undergoing contemporaneous MR imaging and CT, and a subset of International Stroke Thrombolysis-3 trial participants. Automated delineations of WML on images were validated relative to experts' manual tracings on CT images, and co-registered FLAIR MR imaging, and ratings were performed by using two conventional ordinal scales. Analyses included correlations between CT and MR imaging volumes, and agreements between automated and expert ratings. Results Automated WML volumes correlated strongly with expert-delineated WML volumes at MR imaging and CT (r2 = 0.85 and 0.71 respectively; P < .001). Spatial-similarity of automated maps, relative to WML MR imaging, was not significantly different to that of expert WML tracings on CT images. Individual expert WML volumes at CT correlated well with each other (r2 = 0.85), but varied widely (range, 91% of mean estimate; median estimate, 11 mL; range of estimated ranges, 0.2-68 mL). Agreements (κ) between automated ratings and consensus ratings were 0.60 (Wahlund system) and 0.64 (van Swieten system) compared with agreements between individual pairs of experts of 0.51 and 0.67, respectively, for the two rating systems (P < .01 for Wahlund system comparison of agreements). Accuracy was unaffected by established infarction, acute ischemic changes, or atrophy (P > .05). Automated preprocessing failure rate was 4%; rating errors occurred in a further 4%. Total automated processing time averaged 109 seconds (range, 79-140 seconds). Conclusion An automated method for quantifying CT cerebral white matter lesions achieves a similar accuracy to experts in unselected and multicenter cohorts.

Relationship of cardiac biomarkers with white matter hyperintensities in cardioembolic stroke due to atrial fibrillation and/or rheumatic heart disease

White matter hyperintensities (WMHs), which are common in elderly people and contribute to age-related disability, can coexist with cardiac injury. It remains unclear whether cardiac biomarkers are associated with WMHs.To investigate this question, we prospectively recruited patients with cardioembolic stroke due to atrial fibrillation (AF) and/or rheumatic heart disease (RHD). Four cardiac biomarkers were measured: myoglobin, high-sensitivity cardiac troponin T (hs-cTnT), creatine kinase-MB, and terminal pro-brain natriuretic peptide. WMHs in periventricular and deep white matter were assessed separately.In the entire sample of 171 patients, 120 (70.2%) presented with WMHs, of whom 18 (10.5%) presented with moderate to severe deep white matter hyperintensities (DWMH) and 55 (32.2%) presented with moderate to severe periventricular hyperintensities (PVH). Risk of moderate to severe PVH, after adjusting for confounders, was 2.460-fold higher in patients with high myoglobin levels than in those with low levels, and the risk was 2.608-fold higher in patients with high hs-cTnT levels than in those with low levels. There were no significant associations between any of the 4 cardiac biomarkers and moderate to severe DWMH.This prospective observational study provides new evidence of the potential relationship of cardiac biomarkers with WMHs in patients with cardioembolic stroke due to AF and/or RHD. We found that elevated myoglobin levels and high hs-TnT levels were independently associated with the presence of moderate to severe PVH. Further studies are required to test our findings and explore whether cardiac biomarkers contribute directly to WMHs pathogenesis.

Metabolically healthy obesity and risk of leukoaraiosis; a population based cross-sectional study

Metabolically healthy obese (MHO) individual is known to be defended from the metabolic complications of obesity. Leukoaraiosis, which is commonly detected on brain magnetic resonance imaging (MRI), is now recognized as a risk of stroke, dementia and death. However, the association between MHO and the prevalence of leukoaraiosis is unclear. In this cross-sectional study of 796 participants who received a medical examination program, we investigated the association between MHO and the prevalence of leukoaraiosis. We used common clinical markers for definition of metabolic healthy status: blood pressure, fasting plasma glucose, triglycerides and high-density lipoprotein cholesterol concentrations. Obesity was defined by body mass index ≥25.0 kg/m². We diagnosed leukoaraiosis by fluid-attenuated inversion recovery without hypointensity on T1-weighted images or the presence of a hyperintensity on T2-weighted images. The crude prevalence proportion of leukoaraiosis was 44.5% (case/n = 171/384) in metabolically healthy nonobese (MHNO) individual, 46.3% (44/95) in MHO individual, 62.3% (114/183) in metabolically unhealthy nonobese (MUNO) individual or 56.6% (77/136) in MUO individual. The odds ratios of prevalence of leukoaraiosis were 1.19 (95% CI 0.74-1.90, p = 0.471) for MHO, 1.79 (1.22-2.62, p = 0.003) for MUNO and 1.56 (1.03-2.37, p = 0.037) for MUO individuals after adjusting for sex, age, smoking statues, habit of exercise and alcohol, compared with MHNO individual. We revealed that MHO individuals were not related with the higher risk of leukoaraiosis, whereas MUNO and MUO individuals were.

Characteristics of Cerebral Hemodynamics in Patients with Ischemic Leukoaraiosis and New Ultrasound Indices of Ischemic Leukoaraiosis

OBJECTIVE

The diagnosis of ischemic leukoaraiosis (ILA) is based on head magnetic resonance imaging (MRI) and exclusion of other causes of white matter hyperintensities (WMHs). Recent studies have shown increased arterial stiffness and diminished carotid flow in ILA patients. So far, there are very little data on intracerebral hemodynamic parameters in ILA. Due to the specific structure of the intracranial arteries, our aim was to investigate intracerebral hemodynamic parameters in ILA patients and, possibly, to find a reliable ultrasound index of combined intra- and extracranial cerebral arteries.

METHODS

We compared different hemodynamic parameters in the middle cerebral artery (MCA) and local carotid stiffness parameters in 53 ILA patients to 40 gender and risk factor-matched controls with normal head MRI. The ILA diagnosis was based on head MRI and exclusion of other causes of WMH. In addition, we introduced new ischemic leukoariosis indices (ILAi) that are ratios of carotid stiffness parameters and MCA mean blood flow velocity. The diagnostic significance of ILAi for the prediction of ILA was analyzed.

RESULTS

We found significantly lower diastolic, systolic, and mean MCA blood flow velocities and increased carotid stiffness in the ILA group (P ≤ .05). All ILAi significantly differed between the groups (P < .05), were significantly associated with ILA (P < .01), and were sensitive and specific for predicting ILA (P < .05).

CONCLUSION

MCA blood flow velocities in ILA patients are lower compared to risk factor-matched controls. A combination of lower velocities and increased carotid stiffness represented as ILAi could have a potential diagnostic value for ILA.

Ultrasound diagnosis of carotid artery stiffness in patients with ischemic leukoaraiosis

The pathophysiology of ischemic leukoaraiosis (ILA) is unknown. It was recently found that ILA patients have increased aortic stiffness. Carotid stiffness is a more specific parameter and could have value as a non-invasive diagnostic value for ILA. Therefore, using color-coded duplex sonography, we compared local carotid stiffness parameters of 59 patients with ILA with those of 45 well-matched controls. The diagnosis of ILA was based on exclusion of other causes of white matter changes seen on magnetic resonance imaging. Pulse wave velocity β (PWVβ, m/s), pressure-strain elasticity modulus (Ep, kPa), β index and augmentation index (Aix, %) values were higher and arterial compliance (AC, mm(2)/kPa) values were lower in the ILA group; however, only Ep and PWVβ reached statistical significance (p ≤ 0.05). β, Ep and PWVβ exhibited an increasing trend with higher Fazekas score, though only Ep reached significance (p = 0.05). The main conclusion was that Ep and PWVβ could have a diagnostic role in patients with ILA.

Behavioural and psychological symptoms are not related to white matter hyperintensities and medial temporal lobe atrophy in Alzheimer's disease

BACKGROUND

The neuropathology of behavioural and psychological symptoms is much less understood than the neuropathology of cognitive impairment in AD. On MRI, medial temporal lobe atrophy (MTA) is presumed to reflect Alzheimer- type pathology. White matter hyperintensities (WMH) are considered markers of vascular pathology.

AIM

We investigated differences in prevalence of behavioural and psychological symptoms in AD according to the presence of MTA and WMH on MRI.

METHODS

Behavioural and psychological symptoms of 111 consecutive AD patients were assessed using the Neuropsychatric Inventory (NPI). Symptoms were considered present when the score was > or =1. On MRI, MTA was rated using the five-point Scheltens-scale and WMH using the four-point Fazekas-scale. Both MRI measures were dichotomised (MTA: absent 0/1, present 2-4; WMH absent 0/1, present 2/3).

RESULTS

Of the 111 AD patients, 60(55%) had MTA, and 32(29%) had WMH. The presence of MTA was associated with the presence of WMH (chi (2) = 11.8, p < 0.001). The prevalence of behavioural and psychological symptoms--defined as a NPI score of > or =1 on at least one symptom--was 74%.The median NPI score of the total study population was 6(0-41). There was no difference in prevalence according to MTA (p = 0.53) or WMH (p = 0.18). On inspection of individual NPI items, neither MTA, nor WMH was related to any of the symptoms.

CONCLUSIONS

There were no differences in prevalence of behavioural and psychological symptoms according to MTA or WMH, as rated on MRI. This suggests that the occurrence of those symptoms depends on other determinants, such as coping style or genetic make-up.

Diabetes increases atrophy and vascular lesions on brain MRI in patients with symptomatic arterial disease

BACKGROUND AND PURPOSE

Diabetes type 2 (DM2) is associated with accelerated cognitive decline and structural brain abnormalities. Macrovascular disease has been described as a determinant for brain MRI changes in DM2, but little is known about the involvement of other DM2-related factors.

METHODS

Brain MRI was performed in 1043 participants (151 DM2) with symptomatic arterial disease. Brain volumes were obtained through automated segmentation.

RESULTS

Patients with arterial disease and DM2 had more global and subcortical brain atrophy (-1.20% brain/intracranial volume [95%CI -1.58 to -0.82], P<0.0005 and 0.20% ventricular/intracranial volume [0.05 to 0.34], P<0.01), larger WMH volumes (0.22 logtransformed volume [0.07 to 0.38], P<0.005), and more lacunar infarcts (OR 1.75 [1.13 to 2.69], P<0.01) than identical patients without DM2. In patients with DM2, high glucose levels (B-0.12% per mmol/L [-0.23 to -0.01], P<0.05) and diabetes duration (B-0.05% per year [-0.10 to -0.001], P<0.05) were associated with global brain atrophy.

CONCLUSIONS

In patients with symptomatic arterial disease, DM2 has an added detrimental effect on the brain. In patients with DM2, hyperglycemia and diabetes duration contribute to brain atrophy.

Ischemic blood-brain barrier and amyloid in white matter as etiological factors in leukoaraiosis

BACKGROUND

Pathology of white matter, which is observed in ischemic brain, indicates that similar processes contribute to Alzheimer's disease development. These injuries have been seen in the subcortical and periventricular regions. Periventricular white matter changes in ischemic and Alzheimer's disease brain, referred to as leukoaraiosis, are responsible for changes in memory, cognition and behavior. It is not clear whether the blood-brain barrier in ischemic periventricular white matter is altered in aged animals.

METHODS

We studied blood-brain barrier changes with amyloid precursor protein staining around blood-brain barrier vessels. Rats were made ischemic by cardiac arrest. Blood-brain barrier insufficiency, accumulation of amyloid precursor protein and platelets around blood-brain barrier vessels were investigated in ischemic periventricular white matter up to 1-year survival.

FINDINGS

Ischemic periventricualr white matter demonstrated enduring blood-brain barrier changes. Toxic fragments of amyloid precursor protein deposits were associated with the blood-brain barrier vessels. Moreover our investigation revealed platelet aggregates in- and outside blood-brain barrier vessels. Toxic parts of amyloid precursor protein and platelet aggregates correlated very well with blood-brain barrier permeability.

CONCLUSIONS

Progressive injury of the ischemic periventricular white matter may be caused not only by a degeneration of neurons destroyed during ischemia but also by damage in blood-brain barrier. Chronic ischemic blood-brain barrier insufficiency with accumulation of toxic components of amyloid precursor protein in the periventricular white matter perivascular space, may gradually over a lifetime, progress to leukoaraiosis and finally to severe dementia.

[The effect of ischemia-related leukoaraiosis on the conscious disturbance after stroke]

OBJECTIVE

To explore the effect of leukoaraiosis on conscious disturbance in patients with acute cerebral infarction.

METHODS

A follow-up study including 138 patients with acute cerebral infarction matched with the diagnostic criteria of the Forth Cerebrovascular Disease Conference, were carried out. Patients were divided into two groups, using MRI to estimate the white substance process around cerebral ventricle, including 78 of them with leukoaraiosis and 60 without leukoaraiosis were followed up using Glasgow coma scale scores and England OCSP classification in 1 month, 3 month and 6 month after onset.

RESULTS

The independent factors of conscious disturbance included leukoaraiosis (OR = 5.294, 95% CI: 1.451-19.318), and OCSP classification (TACI and POCI especially) (OR = 14.489, 95% CI: 4.121-50.934). At the initial, the first month and the third month of the stroke episodes, significant difference (P < 0.05) was noticed when using Glasgow coma scales, and the scales in leukoaraiosis group was lower than the control.

CONCLUSION

TACI and POCI in OCSP classification were independent risk factors of conscious disturbance, and leukoaraiosis was also the independent factor. The incidence of conscious disturbance after stroke in patients with leukoaraiosis were lower than in that without leukoaraiosis. On the other hand, the degree of conscious disturbance was more serious and slower than those without leukoaraiosis, suggesting that the effect of leukoaraiosis was duplicate for conscious disturbance. Because patients with leukoraiosis had tolerance of chronic cerebral ischemia. The number of patients with conscious disturbance after stroke was fewer relatively. Leukoaraiosis had inactive effect for amelioration of conscious disturbance after three months of the episode. The grouping of OCSP played a primary while leukoaraiosis playing a secondary role, despite the patients with or without conscious disturbance after stroke.

Cognitive Performance after Lacunar Stroke Correlates with Leukoaraiosis Severity

BACKGROUND

This study investigates the effect of leukoaraiosis on patients presenting with cognitive impairment after lacunar stroke.

METHODS

Fourty-six patients with cognitive impairment and newly discovered lacunar stroke detected by brain magnetic resonance imaging underwent neuropsychological testing.

RESULTS

Patients with both lacunar infarct and leukoaraiosis performed less well on cognitive measures, compared to those with lacunar infarcts alone. Additionally, leukoaraiosis severity inversely correlated with cognitive performance.

CONCLUSIONS

In patients with lacunar stroke, presence of leukoaraiosis is associated with worse performance in multiple cognitive domains. These findings suggest lacunar infarcts plus leukoaraiosis is a common etiology for vascular dementia.

Treatment of Leukoaraiosis: A Futuristic View

Leukoaraiosis (LA or white matter changes of the brain) is a common finding on brain imaging studies in the elderly people. LA predisposes to dementia, ischemic stroke, intracerebral hemorrhage, and cognitive decline as well as associates with a significant increase in falls and gait disorders. As population ages, the incidence of LA increases and is becoming a major global health problem. Therefore, strategies for its prevention and management are urgently needed. This review includes basic knowledge on the pathophysiology, patterns of clinical presentation, risk factors, and imaging findings of LA. The very last and the most comprehensive part of this review discusses potential therapeutic approaches of the future.

High Prevalence of Leukoaraiosis in Cerebral Magnetic Resonance Images of Patients on Peritoneal Dialysis

BACKGROUND

Leukoaraiosis is a term used to define the abnormal appearance of subcortical white matter of the brain by means of neuroimaging and is regarded as an intermediate surrogate of stroke. The goal of this study is to identify the prevalence of leukoaraiosis and analyze predictors of risk of leukoaraiosis.

STUDY DESIGN

Cross-sectional study.

SETTING & PARTICIPANTS

57 peritoneal dialysis (PD) patients without diabetes treated in 3 academic medical-associated dialysis units who did not have a history of cerebrovascular disease or neurological symptoms compared with a convenience sample of 57 age- and sex-matched hypertensive control subjects with normal renal function.

PREDICTOR

End-stage renal disease treated by PD compared with hypertension, adjusted for clinical and laboratory characteristics.

OUTCOME & MEASUREMENT

Hyperintense areas on magnetic resonance imaging T2 high-signal intensity scoring system.

RESULTS

The prevalence of leukoaraiosis was significantly greater in patients on PD therapy than controls (68.4% versus 17.5%; P < 0.001). High T2 signal intensity score in patients on PD therapy compared with controls was significantly higher in the anterior circulation of the brain, relatively sparing the posterior fossa. End-stage renal disease, age, and poor control of blood pressure were significant independent predictors of leukoaraiosis.

LIMITATIONS

There is the possibility that biases regarding the selection of enrolled patients had an influence on a study result.

CONCLUSIONS

Cerebral magnetic resonance imaging of PD patients without evidence of cerebrovascular disease showed a high prevalence of leukoaraiosis in the anterior circulation of the brain. Old age, poorly controlled hypertension, and the PD procedure itself and/or end-stage renal disease seem to be associated with the presence of leukoaraiosis.

Small-Vessel Vascular Disease in Human Immunodeficiency Virus Infection: The Hawaii Aging with HIV Cohort Study

BACKGROUND

This study is designed to determine the relationship between age and occurrence of cerebral manifestations of small-vessel ischemic vascular disease in human immunodeficiency virus (HIV)-seropositive individuals.

METHODS

Periventricular leukoaraiosis severity and white matter lesion volume were determined by magnetic resonance imaging of the brain of 57 HIV-seropositive individuals.

RESULTS

Cerebral small-vessel ischemic vascular disease manifestations correlated with age and systolic blood pressure, but not with HIV infection-related parameters.

CONCLUSIONS

These findings suggest that, in the era of highly active antiretroviral therapy, leukoaraiosis severity and white matter lesion volume may be more indicative of small-vessel ischemic vascular disease than HIV-related CNS pathology, and support the need for aggressive treatment of vascular risk factors in HIV-seropositive individuals.

Association of Ambulatory Blood Pressure With Ischemic Brain Injury

Cerebral white matter hyperintensities on brain MRI (leukoaraiosis) are associated with increased risk of stroke and dementia. To assess the relationships of blood pressure level and circadian pattern with leukoaraiosis, we obtained 24-hour ambulatory blood pressure recordings and brain magnetic resonance images in 343 white and 267 black adults who were members of sibships that had ≥2 siblings with essential hypertension. In multiple linear regression models, factors associated with greater leukoaraiosis in both racial groups included age ( P ≤0.002), homocysteine levels ( P ≤0.006), and brain volume ( P ≤0.008). In blacks, ambulatory blood pressure measures associated with greater leukoaraiosis were higher awake, asleep, and 24-hour systolic and diastolic levels ( P ≤0.009 for each). In addition, there was a trend for smaller nocturnal declines in systolic and diastolic levels (ie, nondipping patterns) to be associated with greater leukoaraiosis, and all of these associations, except nondipping of diastolic level, remained or became significant after controlling for office blood pressure ( P <0.05 for each). In whites, among ambulatory blood pressure measures, only higher asleep diastolic levels trended toward association with greater leukoaraiosis. However, similar to findings in blacks, nondipping of systolic and diastolic ambulatory blood pressure levels were each associated with greater leukoaraiosis ( P ≤0.008), and all of these associations remained or became significant after controlling for office blood pressure ( P ≤0.009 for each). Higher ambulatory blood pressure levels and a nondipping circadian pattern contribute to greater leukoaraiosis volume after controlling for office blood pressure.

Chemical events behind leukoaraiosis: medicinal chemistry offers new insight into a specific microcirculation disturbance in the brain (a chemical approach to a frequent cerebral phenotype)

Leukoaraiosis (LA), one of the most frequent causes of cognitive disturbances, is presumed to involve vascular demyelinization and cerebral small-vessel diseases. Although it has been suggested that the development of LA is associated with cerebral circulatory disturbances, the pathomechanism of this circulatory problem is not completely understood. Extensive debate is continuing as regards the detailed features of the circulatory disturbances in LA. An endothelial dysfunction may lead to breakdown of the blood-brain barrier, thereby resulting in chronic toxic edema in the perivascular areas. This can then cause the slow development of LA. Endothelial dysfunctions may also give rise to molecular events involving a shift in the O(2) and CO(2) trafficking system in the red blood cells, which will result in special complex microcirculation disturbances in the white matter of the brain; these molecular phenomena may therefore account for chronic slight hypoxia leading to the development of LA. This article discusses these hypothetical alternative molecular events behind LA. The review also illustrates how medicinal chemistry can offer new insight into a common, but still mysterious cerebral phenotype.

Leukoaraiosis as a predictor for mortality and morbidity after an acute ischaemic stroke

INTRODUCTION

Leukoaraiosis (LA) is a term that defines an abnormal appearance of the subcortical white matter of the brain on neuroimaging. This study was done to evaluate the predictive value of LA in terms of mortality, disability and cognitive decline at three months post-stroke and also to identify the risk factors that are independently associated with LA in a stroke population.

METHODS

This was a prospective observational study of all patients with acute ischaemic stroke who were admitted to Hospital Universiti Kebangsaan Malaysia from June to November 2004. A single observer using the pre-defined diagnostic criteria recorded the information on demography, Barthel Index and mini-mental state examination. LA was diagnosed on brain computed tomography alone.

RESULTS

60 patients were recruited into the study. Three patients (five percent) died and LA was present in 29 patients (48 percent). There was no significant association between LA and mortality (p-value equals 0.89). The independent risk factors that were associated with LA were age (odds-ratio [OR] 4.43; 95 percent confidence interval [CI] 1.28-15.27) and hypertension (OR 14.3; 95 percent CI 1.40-147.42). There was a significant association between LA with early dementia (OR 3.53; 95 percent CI 1.19-10.49). However, LA did not significantly predict any functional disability (Barthel Index is less than 60) in the study population (p-value equals 0.45).

CONCLUSION

Development of LA correlates significantly with ageing and hypertension. The presence of LA can also predict early cognitive dysfunction but is not associated with functional disability at three months post-stroke.

Family-based association study of matrix metalloproteinase-3 and -9 haplotypes with susceptibility to ischemic white matter injury

Susceptibility to ischemic damage to the subcortical white matter of the brain has a strong genetic basis. Dysregulation of matrix metalloproteinases (MMPs) contributes to loss of cerebrovascular integrity and white matter injury. We investigated whether sequence variation in the genes encoding MMP3 and MMP9 is associated with variation in leukoaraiosis volume, determined by magnetic resonance imaging, in non-Hispanic whites and African-Americans using family-based association tests. Seven hundred and fifty-six white and 671 African-American individuals from sibships ascertained through two or more siblings with hypertension were genotyped for 7 and 8 haplotype-tagging polymorphisms in the MMP3 and MMP9 genes, respectively. MMP3 sequence variation was significantly associated with variation in leukoaraiosis volume in Whites. Two common haplotypes with opposing relationships to leukoaraiosis volume were identified. MMP9 sequence variation was also significantly associated with variation in leukoaraiosis volume in both African-Americans and Whites. Different haplotypes contributed to these associations in the two racial groups. These findings add to the growing body of evidence from animal models and human clinical studies suggesting a role of MMPs in ischemic white matter injury. They provide the basis for further investigation of the role of these genes in susceptibility and/or progression to clinical disease.

Cerebral White Matter Hyperintensities on MRI: Current Concepts and Therapeutic Implications

BACKGROUND

White matter hyperintensities (WMH) are commonly observed MRI abnormalities in the elderly, which generally reflect covert vascular brain injury. WMH cumulatively produce substantial neurologic, psychiatric, and medical morbidity. This review provides an overview of current knowledge on vascular WMH, and describes some pharmacological agents that may have a role in mitigating this condition.

SUMMARY OF REVIEW

This review has two main focus areas. The first is a discussion of currently available knowledge regarding the public health burden, pathogenesis, and various risk factors associated with the presence of vascular white matter lesions noted on brain MRI. The second section of the article details the mechanistic and clinical basis for promising pharmacological treatment modalities that could potentially prevent progression of ischemic cerebral white matter brain injury. Many of these therapies are already of proven efficacy in preventing recurrent stroke.

CONCLUSIONS

Individuals with vascular white matter lesions on MRI may represent a potential target population likely to benefit from secondary stroke prevention therapies.

Age, Hypertension, and Lacunar Stroke Are the Major Determinants of the Severity of Age-Related White Matter Changes

BACKGROUND

Age-related white matter changes (ARWMC), seen on neuroimaging with high frequency in older people, are thought to be consequent to the effect of vascular risk factors and vascular diseases including hypertension and stroke. Among the proofs conventionally required for a factor to be considered a risk factor for a definite pathology, there is the demonstration of a trend in risk exposure related to disease severity. We sought whether such a trend existed in the association of vascular risk factors or comorbidities with the severity of ARWMC aiming particularly at further elucidating the relative roles of hypertension and stroke in this regard.

METHODS

The LADIS (Leukoaraiosis and Disability) Study is evaluating the role of ARWMC as an independent determinant of the transition to disability in the elderly. Six hundred and thirty-nine nondisabled subjects (mean age 74.1+/-5.0, M/F: 288/351) with ARWMC of different severity grades on MRI (mild, moderate, or severe according to the Fazekas scale) were assessed at baseline for demographics, vascular risk factors, and comorbidities, and are being followed up for 3 years.

RESULTS

Age, frequency of hypertension and history of stroke increased along with increasing ARWMC severity independently of other factors. For hypertension, however, this occurred only in subjects without a stroke history, while for stroke history, it mainly depended on lacunar stroke. The amount of cigarettes smoked and the interaction between hypercholesterolemia and smoking predicted only the most severe ARWMC grade.

CONCLUSIONS

The LADIS Study confirms that age, hypertension and lacunar strokes are the major determinants of ARWMC. Smoking and hypercholesterolemia provide additional risk.

White matter lesions and cognitive impairment as silent cerebral disease in hypertension

Although the pathogenesis and clinical significance of cerebral white matter lesions remain controversial, it is well established that age and hypertension are the most important factors related to the presence of these lesions. Hypertension is known to be the most important factor for developing stroke and vascular dementia. In addition, the presence of cerebral white matter lesions is an important prognostic factor for the development of stroke, and also for cognitive impairment and dementia. The mechanisms underlying hypertension-related cognitive changes are complex and are not yet fully understood. Correlations between cerebral white matter lesions and elevated blood pressure provide indirect evidence that structural and functional changes in the brain over time may lead to lowered cognitive functioning when blood pressure control is poor or lacking.Some authors have suggested that the presence of white matter lesions in hypertensive patients could be considered an early marker of brain damage.

Executive dysfunction in hyperhomocystinemia responds to homocysteine-lowering treatment

An elevated serum homocysteine level is a risk factor for the development of cognitive impairment. Reported is a late-onset case of hyperhomocystinemia due to a vitamin B12 metabolic deficit (cobalamin C) with cognitive impairment, primarily in frontal/executive function. After homocysteine-lowering therapy, the patient's functional and neuropsychological status improved in conjunction with a decrease in leukoariosis on his MRI scan. These findings suggest that homocysteine-related cognitive impairment may be partially reversible.

Relationship of deep white matter hyperintensities and cerebral blood flow in severe carotid artery stenosis

Leukoaraiosis (LA) has been associated with abnormalities of both large and small blood vessels. This study attempts to clarify the pathogenesis of LA by testing the hypothesis that increased frequency of LA with occlusive extra-cranial arterial disease results directly from global reduction in cerebral blood flow (CBF). Thirty-five normal subjects and 55 patients with carotid stenosis (>70%) were studied using MR. CBF was measured using phase contrast MR angiography and LA was scored using previously validated scoring system. Patients were divided into those with evidence of previous infarction on MRI and those without. LA was more severe in patients than in normal subjects (P<0.01) and correlated with age in normal subjects but not in patients. CBF in patients with (809+/-214 ml/min) and without infarction (mean 792+/-181 ml/min) was significantly lower than in normal subjects (mean 1073+/-194 ml/min). There was no correlation between the severity of LA and measured CBF in any group. The severity of LA is greater in patients with severe carotid stenosis but is not correlated to reductions in CBF. This suggests that microvascular abnormality is the dominant pathogenetic factor in LA even in the presence of severe stenotic/occlusive large vessel disease.

Cerebral white matter hyperintense lesions are associated with unstable carotid plaques

OBJECTIVES

The aim of this study was to determine whether unstable carotid plaques, a known risk factor for cerebral emboli, are associated with cerebral white matter lesions.

METHODS

Seventy-one symptomatic patients undergoing magnetic resonance imaging prior to carotid endarterectomy for high grade carotid stenosis were included in this study. The number and volume of white matter hyperintense lesions (WMHL) on fluid attenuated inversion recovery brain scans were compared according to the morphology of carotid plaque based upon the American Heart Association (AHA) histological classification.

RESULTS

Of the 57 patients who had good quality brain scans and non-fragmented carotid plaques, 15 plaques were defined as stable (type V) and 42 as unstable (type VI). After adjustment for the major risk factors affecting WMHL, unstable carotid plaques were found to be associated with more WMHL in the ipsilateral cerebral hemisphere than stable plaques (transformed means 2.50+/-1.2 vs. 1.53+/-1.1, p=0.016), however, there was only a trend towards larger WMHL volumes (p=0.079).

CONCLUSIONS

The observed association between unstable carotid plaques and the number of white matter lesions suggest that thromboembolic plaque activity may contribute to the development of leukoaraiosis, in particular smaller individual lesions. Larger studies are warranted to confirm this finding and explore the potential clinical impact for selecting candidates for carotid endarterectomy.

Ambulatory blood pressure and the brain: A 5-year follow-up

OBJECTIVE

To determine if initial values of casual and ambulatory systolic blood pressure (SBP) predict white matter hyperintensities, insular subcortex hyperintensities, and brain atrophy 5 years later in a group of healthy elderly individuals.

METHODS

The authors studied 155 healthy men and women, aged 55 to 79 years. Two 24-hour ambulatory blood pressure (BP) sessions assessed BP level and variability during waking and sleep. Hyperintensities and total brain volume were quantified by MRI. Procedures were repeated 5 years later in 78% (121) of subjects.

RESULTS

Hyperintensities and brain atrophy increased over time, with greater increases among older subjects. The presence of increased BP level and variability initially and again 5 years later had negative consequences for the brain. Independent of age, the greater the initial SBP, the greater the likelihood that individuals would have severe white matter hyperintensities after 5 years. Also, elevated casual SBP was associated with severe insular subcortex hyperintensities and greater SBP sleep variability with increased brain atrophy.

CONCLUSIONS

Among healthy elderly individuals whose initial, average, casual blood pressure (BP) was relatively low (116.9/71.1 mm Hg), small increases in casual and 24-hour ambulatory BP measures were associated with greater brain atrophy and subcortical lesions after 5 years.

[Clinico-pathology and differential diagnosis of Binswanger's disease]

Pathologically, Binswanger's disease is subcortical periventricular leucoencephalopathy sparing the U fibers. Clinically it is characterised by executive dysfunction, gait problems, urinary incontinence, pseudobulbar palsy, mood disturbances and dementia. The pathomechanism of Binswanger's disease is unclear. It is hypothesized that it results from an ischemic-hypoxic injury of the periventricular white matter, which, in turn, can be caused by a sclerotic elongation of the medullary arteries, widening of the perivascular spaces or decreased brain perfusion due to hypotension or heart disease. The symptoms of Binswanger's disease frequently overlap with those of normal pressure hydrocephalus, vascular parkinsonism and Alzheimer's disease. A diagnostic criterion of Binswanger's disease is radiologically demonstrated leukoaraiosis, which, on the other hand, is not equivalent with Binswanger's disease. A good clinical response after lumbar puncture or shunt implantation might lead to confusion with normal pressure hydrocephalus, which further complicates the clinical diagnosis. It is likely that among the above mentioned disorders there are a number of transitional forms and overlaps, which might be explained by the common pathomechanism of disturbance in cerebrospinal fluid circulation.

Alzheimer's disease with and without cerebral infarcts

OBJECTIVE

To compare the clinical and pathological features of Alzheimer's disease (AD) patients with and without associated cerebral infarcts (CI).

METHODS

The consecutive records of 57 prospectively studied demented patients fulfilling the CERAD criteria for the pathological diagnosis of AD were reviewed. Cases with cortical Lewy bodies were excluded. CI were found in 22 cases (39%) (AD+CI group): large infarcts (5), lacunes (13) and/or hippocampal sclerosis (4), and were absent in 35 cases (AD group). Microscopic infarcts, cribiform change, amyloid angiopathy, and white matter rarefaction were not considered in this classification, but were quantified. Cortical atrophy, neurofibrillary tangle and senile plaque (diffuse and neuritic) load were also measured. Pathological evaluation was independent of clinical information. Clinical and pathological data were compared between both groups.

RESULTS

AD+CI cases were significantly older, more commonly female, less educated, and more often had blue collar occupations, sleep disturbances, frontal release signs, and EEG spikes than AD cases. Other differences found (acute/subacute onset, behavioral disturbances, and leukoaraiosis on CT scan) disappeared after controlling for age. The frequency of known vascular risk factors and focal motor and sensory signs did not differ between the groups, which showed remarkable clinical similarity overall. The only significant differences on pathological exam were hippocampal microinfarcts and white matter lesions, although there was a trend for lower neurodegenerative lesion load in the AD+CI group. The ischemic lesions were located in temporal lobe in 50% of AD+CI patients; these cases had a significantly lower neocortical neurodegenerative lesion load than those with CI in other sites.

CONCLUSIONS

The presence of CI in AD increases significantly with age, but has scarce influence on the clinical features, and cannot be predicted from common vascular risk factors. In spite of a trend, there are no major differences in neurodegenerative lesion load between AD and AD+CI groups, except when CI are located in the temporal lobe (including hippocampus), suggesting that this location may be important in the physiopathology of mixed vascular and AD dementia.

Different progression rates for deep white matter hyperintensities in elderly men and women

The authors investigated the progression of white matter hyperintensities (WMHs) in a large population of elderly men and women. After 3 years of follow-up, women had accumulated approximately twice as much deep WMH (DWMH) as men. The progression of periventricular WMH was the same for men and women. Gender differences may affect the pathogenesis of DWMH, which in turn may result in different clinical consequences in women.