Binswanger's disease in the absence of chronic arterial hypertension. A case report with clinical, radiological and immunohistochemical observations on intracerebral blood vessels

Generalized chorea associated with subcortical leukoaraiosis of Binswanger type: a case report

Binswanger disease (BD) involves injuries to the brain small vessels, resulting to gradually progressive subcortical ischemia. This disorder manifests with dementia, gait abnormalities, upper motor signs and parkinsonism, and presents as extensive, confluent, bilateral cerebral white matter hyperintensities in the MRI. Cases of BD typically manifests with vascular risk factors, such as hypertension and multiple strokes. We report a unique case of a Filipino patient whom we have diagnosed with BD presenting with no cardinal signs of parkinsonism, but with generalized choreiform movement disorder and without a history of hypertension and symptomatic strokes. To our knowledge, this is the first report presenting an adult patient with subcortical leukoaraiosis of Binswanger type associated with a hyperkinetic movement disorder.

Endothelial damage, vascular bagging and remodeling of the microvascular bed in human microangiopathy with deep white matter lesions

White matter lesions (WMLs) are a common manifestation of small vessel disease (SVD) in the elderly population. They are associated with an enhanced risk of developing gait abnormalities, poor executive function, dementia, and stroke with high mortality. Hypoperfusion and the resulting endothelial damage are thought to contribute to the development of WMLs. The focus of the present study was the analysis of the microvascular bed in SVD patients with deep WMLs (DWMLs) by using double- and triple-label immunohistochemistry and immunofluorescence. Simultaneous visualization of collagen IV (COLL4)-positive membranes and the endothelial glycocalyx in thick sections allowed us to identify endothelial recession in different types of string vessels, and two new forms of small vessel/capillary pathology, which we called vascular bagging and ghost string vessels. Vascular bags were pouches and tubes that were attached to vessel walls and were formed by multiple layers of COLL4-positive membranes. Vascular bagging was most severe in the DWMLs of cases with pure SVD (no additional vascular brain injury, VBI). Quantification of vascular bagging, string vessels, and the density/size of CD68-positive cells further showed widespread pathological changes in the frontoparietal and/or temporal white matter in SVD, including pure SVD and SVD with VBI, as well as a significant effect of the covariate age. Plasma protein leakage into vascular bags and the white matter parenchyma pointed to endothelial damage and basement membrane permeability. Hypertrophic IBA1-positive microglial cells and CD68-positive macrophages were found in white matter areas covered with networks of ghost vessels in SVD, suggesting phagocytosis of remnants of string vessels. However, the overall vessel density was not altered in our SVD cohort, which might result from continuous replacement of vessels. Our findings support the view that SVD is a progressive and generalized disease process, in which endothelial damage and vascular bagging drive remodeling of the microvasculature.

Cytopathological alterations and therapeutic approaches in Binswanger's disease

Binswanger's disease (BD) is a condition characterized by prominent brain atrophy with ventricular dilatation, diffuse white matter (WM) lesions and a scattering of lacunar infarcts. BD patients have dementia, and have vascular risk factors, focal cerebrovascular deficits and evidence of subcortical cerebral dysfunction. From our clinical studies, the most effective prophylaxis against the development of BD is to manage the hypertension, especially a high nocturnal blood pressure, in the early stage patients showing only a scattering of lacunes and/or mild WM lesions. The pathogenesis of BD is likely to be chronic cerebral ischemia due to hypertensive small artery disease with capillary collagenosis, which causes the multiple lacunes and the alterations in the glia and axons. In addition, arterial hypertension and a subsequent dysfunction of the blood-brain barrier (BBB) may cause the WM lesions. A compromised BBB will permit the entry of serum components, immunoglobulins, complements and fibrinogen into the perivascular neural parenchyma. These substances may subsequently activate both astro- and microglia and thus damage the myelin structures. Experimentally, immunosuppressants, cyclosporin A and FK 506 suppressed both the glial activation and WM changes after chronic cerebral hypoperfusion. The pro-thrombotic state of the microcirculation in BD patients may also contribute to local inflammation and the BBB dysfunction, because thrombin and prostanoids are involved in various tissue reactions including brain edema and glial activation. Therefore, novel therapeutic approaches using the administration of anti-thrombin and cyclo-oxygenase-2 inhibitors as well as immunosuppressants may be useful for preventing the progression of BD.

Microarray RNA expression analysis of cerebral white matter lesions reveals changes in multiple functional pathways

BACKGROUND AND PURPOSE

White matter lesions (WML) in brain aging are linked to dementia and depression. Ischemia contributes to their pathogenesis but other mechanisms may contribute. We used RNA microarray analysis with functional pathway grouping as an unbiased approach to investigate evidence for additional pathogenetic mechanisms.

METHODS

WML were identified by MRI and pathology in brains donated to the Medical Research Council Cognitive Function and Ageing Study Cognitive Function and Aging Study. RNA was extracted to compare WML with nonlesional white matter samples from cases with lesions (WM[L]), and from cases with no lesions (WM[C]) using RNA microarray and pathway analysis. Functional pathways were validated for selected genes by quantitative real-time polymerase chain reaction and immunocytochemistry.

RESULTS

We identified 8 major pathways in which multiple genes showed altered RNA transcription (immune regulation, cell cycle, apoptosis, proteolysis, ion transport, cell structure, electron transport, metabolism) among 502 genes that were differentially expressed in WML compared to WM[C]. In WM[L], 409 genes were altered involving the same pathways. Genes selected to validate this microarray data all showed the expected changes in RNA levels and immunohistochemical expression of protein.

CONCLUSIONS

WML represent areas with a complex molecular phenotype. From this and previous evidence, WML may arise through tissue ischemia but may also reflect the contribution of additional factors like blood-brain barrier dysfunction. Differential expression of genes in WM[L] compared to WM[C] indicate a "field effect" in the seemingly normal surrounding white matter.

Pathomechanism of leukoaraiosis: a molecular bridge between the genetic, biochemical, and clinical processes (a mitochondrial hypothesis)

Ischemic demyelination in the white matter of the brain is a frequent clinical entity. In neuroimaging terms, it is referred to as leukoaraiosis (LA). LA can reflect a broad public health problem, which is caused by a cognitive impairment ranging from mild slowness of thinking to full-blown subcortical dementia. One-quarter of subjects aged 65 yr or over are affected by some degree of white matter changes. There are a number of genetic factors that can be associated with circulatory disturbances of the white matter of the brain. A slight chronic hypoperfusion or an endothelial dysfunction associated with unfavorable genetic variations such as methylenetetrahydrofolate reductase C677T variation and angiotensin-converting enzyme I/D polymorphism then may lead indirectly to a malfunction of the molecular cross-talk between the nucleus and the mitochondria. This results in a decrease in the production of energy in the glia cells and thereby the beginning of demyelination. From another aspect, the presence of either the apolipoprotein E 2 or 4 alleles may cause an increased vulnerability to a slight chronic hypoperfusion of the white matter by reducing the range of mechanical and chemical flexibility of the glial cytoskeleton. In consequence of the chronic hypoperfusion, the functionally damaged kinesin protein gives rise also to the disturbances of the trafficking of the myelin basic protein mRNAs in the oligodendrocytes. On the basis of the current knowledge on LA, this article suggests a hypothetical molecular bridge between the genetic, biochemical, and clinical processes.

White matter lesions in an unselected cohort of the elderly: astrocytic, microglial and oligodendrocyte precursor cell responses

White matter lesions in an unselected cohort of the elderly: astrocytic, microglial and oligodendrocyte precursor cell responsesHyperintense lesions are frequently identified in T2-weighted magnetic resonance images (MRI) in the ageing brain. The pathological correlate and pathogenesis of white matter lesions (WML) remain unclear, and it is uncertain whether pathology and pathogenesis differ in periventricular lesions (PVL) compared with deep subcortical lesions (DSCL). Therefore we characterized astrocytic, microglial and oligodendrocyte responses in PVL and DSCL and compared them with control white matter using immunohistochemistry. Both PVL and DSCL were associated with severe myelin loss and increased microglia (P = 0.069 and P < 0.001), compared with nonlesional aged brain. Clasmatodendritic astroglia, immunoreactive for the serum protein fibrinogen, were present in 67% of PVL examined and 42% of DSCL. Compared with control and DSCL cases, more MAP-2 +13 positive remyelinating oligodendrocytes (P = 0.003 and P = 0.035) and platelet-derived growth factor alpha receptor positive reactive astrocytes (P < 0.001) were present in the perilesional white matter of PVL. In addition to a role for hypoperfusion, our data suggest that dysfunction of the blood-brain barrier may also contribute to the pathogenesis of a proportion of cerebral WML associated with ageing, and that attempts at remyelination are only associated with PVL and not DSCL.

Clinicopathological investigation of vascular parkinsonism, including clinical criteria for diagnosis

Vascular parkinsonism (VP) is difficult to diagnose with any degree of clinical certainty. We investigated the importance of macroscopic cerebral infarcts and pathological findings associated with microscopic "small vessel disease" (SVD) in the aetiology of VP. The severity of microscopic SVD pathology (perivascular pallor, gliosis, hyaline thickening, and enlargement of perivascular spaces) and the presence of macroscopically visible infarcts were assessed in 17 patients with parkinsonism and no pathological evidence of either Parkinson's disease or any histopathological condition known to be associated with a parkinsonian syndrome, and compared with age-matched controls. Microscopic SVD pathology was significantly more severe in the parkinsonian brains. Most patients presented with bilateral bradykinesia and rigidity together with a gait disorder characterised predominantly by a shuffling gait. Four patients presented acutely with hemiparesis and then progressed to develop a parkinsonian syndrome. They could be distinguished from the remaining VP patients by the presence at autopsy of macroscopically visible lacunar infarcts in regions where contralateral thalamocortical drive might be reduced. The clinical features at presentation varied according to the speed of onset and the underlying vascular pathological state. New clinical criteria for a diagnosis of VP are proposed based on the clinicopathological findings of this study.

Evaluation of the roles of common genetic mutations in leukoaraiosis

OBJECTIVES

Leukoaraiosis, a relatively frequent neuroimaging entity, is presumed to be primarily a vascular problem. However, it can be explained only in part by vascular risk factors. With the assumption of genetic susceptibility, the roles of common genetic polymorphisms and mutations in leukoaraiosis were examined in this study.

MATERIAL AND METHODS

A detailed clinical scrutiny of 843 Hungarian neurological patients with mild cognitive-like complaints revealed 229 subjects with leukoaraiosis that was probably vascular in origin: 143 with leukoaraiosis alone (group 1), and 86 with leukoaraiosis plus cerebral infarction (group 2). In all 229 patients, the methylenetetrahydrofolate reductase C677T (MTHFR C677T) mutation and angiotensin-converting enzyme (ACE I/D) polymorphism were examined by means of the PCR technique. The prevalences of the different genotypes for the examined mutations in the 2 groups were analysed in comparison with the data on 362 neuroimaging alteration-free subjects as controls.

RESULTS

The ACE D/D genotype (38.37%, P<0.0005; OR 2.46, 95% CI, 1.49-4.08) and ACE D allele (61%; P<0.001) were more frequent in group 2 than in the control group (20.17%; 47%). Neither the homozygous nor the heterozygous MTHFR C677T mutation alone was found to be a risk factor for leukoaraiosis. The homozygous MTHFR C677T mutation combined with the ACE D/D genotype was significantly more frequent in group 1 (11.89%, P<0.0005; OR 4.75, 95% CI, 2.12-10.65), in group 2 (12.79%, P<0.0005; OR 5.16, 95% CI, 2.12-12.6) and in combined group 1+2 (12.23%, P<0.0005; OR 4.9, 95% CI, 2.33-10.3) than in the control group (2.76%).

CONCLUSION

These data indicate that the contributions of the ACE D/D genotype and the homozygous MTHFR C677T mutation to leukoaraiosis should be taken into consideration not as major, but as additive factors. These findings draw attention to the fact that genetic polymorphisms that alone are insignificant can be risk factors for leukoaraiosis if they cluster in the same subjects.

Ultrastructural and permeability features of microvessels in the periventricular area of senescence-accelerated mice (SAM)

Brain transfer of intravenously injected horseradish peroxidase (HRP) and the ultrastructural features of the vessels were examined in periventricular areas in senescence-accelerated mice (SAMP8), which show age-related deficits in learning and memory, and senescence-accelerated resistant mice (SAMR1), which do not show age-related deficits. In all mice examined with light microscopy, staining reaction for HRP was seen in the periventricular area adjacent to the medial side of the lateral ventricle. Electron microscopic examination in the periventricular area of young and old mice of both strains showed that the staining reaction for HRP appeared in the vesicular profiles of the endothelial cytoplasm, the cytoplasm of the perivascular cells, the basal lamina, and the adjoining extracellular spaces of the white matter, suggesting an incomplete blood-brain barrier (BBB) in the periventricular white matter. In addition, irregularly thickened endothelial cell cytoplasm, membranous inclusions within the basal lamina, and electron-dense endothelial cell cytoplasm were occasionally seen in aged SAMP8 mice. These findings were not observed in 3-month-old SAMP8 mice and 3- and 13-month-old SAMR1 mice. Perivascular collagen deposits were also frequently seen in aged SAMP8 mice. These findings indicate that the endothelial cells and pericytes in the periventricular white matter in aged SAMP8 mice have an ultrastructure with damaged BBB function. Intravascular substances can easily penetrate the periventricular white matter and the BBB of the vessels in the area can be deteriorated with aging in SAMP8 mice.

Pathogenesis of leukoaraiosis: a review

BACKGROUND

Changes in the cerebral hemispheric white matter, detectable with increasing frequency by modern neuroimaging methods, are associated with aging and conceivably may contribute to the development of specific cognitive deficits. The pathogenesis of these cerebral white matter abnormalities (sometimes described as leukoaraiosis) is unknown. This review evaluates the available evidence in support of the hypothesis that the etiology of leukoaraiosis is related to a specific type of cerebral ischemia and highlights mechanisms by which ischemic injury to the brain may induce selected structural alterations limited to the cerebral white matter.

SUMMARY OF REVIEW

The review is based on the critical analysis of over 100 publications (most appearing in the last decade) dealing with the anatomy and physiology of the arterial circulation to the cerebral white matter and with the pathogenesis of leukoaraiosis.

CONCLUSIONS

A significant number of clues support the hypothesis that some types of leukoaraiosis may be the result of ischemic injury to the brain. Structural changes affecting the small intraparenchymal cerebral arteries and arterioles that are associated with aging and with stroke risk factors, altered cerebral blood flow autoregulation, and the conditions created by the unique arterial blood supply of the hemispheric white matter each seem to contribute to the development of leukoaraiosis. To the best of our ability to interpret current information, the type of ischemic injury that is most likely responsible for these white matter changes involves transient repeated events characterized by moderate drops in regional cerebral blood flow that induce an incomplete form of infarction. This hypothesis could be tested in appropriate experimental models.

Fundamental pathological lesions in vascular dementia

This review concerns the fundamental cerebral lesions in cases of vascular dementia. Extracerebral vascular alterations are dominated by atherosclerosis with or without thrombosis. In addition, occlusion of extracerebral arteries can be induced by thrombo-embolism and in rare cases by other vascular diseases, chiefly arteritis. Intracerebral microangiopathies are usually of arteriolosclerotic or hyalinotic types in which there is degeneration of smooth muscle cells of the media and deposition of components of extracellular matrix, chiefly collagens. Ageing, chronic hypertension, hyperlipidemias and diabetes are important factors inducing vascular lesions. The vascular lesions, often combined with systemic factors, may produce various ischemic and edematous alterations of the brain parenchyma. Occlusion and obliteration of arteries (macroangiopathy) are associated with large infarcts, whereas microangiopathy may cause lacunar infarcts and some forms of white matter degeneration. Cases of vascular dementia usually present many types of lesions in the brain parenchyma and its arterial supply. The extent and location of the injuries differ considerably from case to case. Location of the lesions, volume of destroyed tissue, multiplicity and bilateral occurrence are most important parameters underlying the clinical manifestations in vascular dementia. A strategic location of a small injury is in some cases of particular importance.

Alterations of the blood-brain barrier and glial cells in white-matter lesions in cerebrovascular and Alzheimer's disease patients

BACKGROUND AND PURPOSE

The underlying cause of white-matter lesions, which are frequent findings in cerebrovascular disease (CVD) and Alzheimer's disease (AD), remains uncertain. We performed immunohistochemical analysis of serum protein extravasation to investigate the function of the blood-brain barrier in white-matter lesions.

METHODS

White-matter lesions were estimated by use of Kluver-Barrera staining in patients diagnosed clinicopathologically as having ischemic CVD (n = 14) and AD (n = 12) and from nonneurological control subjects (n = 6). Axonal damages were investigated by use of immunohistochemistry for amyloid protein precursor. Alteration of the blood-brain barrier was examined with fibrinogen and immunoglobulins used as markers. The numbers of HLA-DR-positive microglia and glial fibrillary acidic protein-positive astroglia were examined comparatively.

RESULTS

White-matter lesions were graded as normal (grade 0) in 14 of the 32 cases (44%), slight (grade I) in 10 cases (31%), moderate (grade II) in 6 cases (19%), and severe (grade III) in 2 cases (6%). Amyloid precursor protein was accumulated most frequently in grade II white-matter lesions. Immunohistochemistry for serum proteins labeled astroglial cell bodies and their processes, which seemed to have sequestered extravasated proteins. The groups with detectable white-matter lesions had significantly higher grading scores for fibrinogen and immunoglobulins than the control group (P < .05). Although the higher scores for serum protein extravasation were statistically significant in ischemic CVD cases (P < .05), there was no significant increase in AD cases. Activated microglia and astroglia were more numerous in the groups with white-matter lesions in both ischemic CVD and AD cases, although this increase in the number of astroglia was not evident in regions with clasmatodendrosis.

CONCLUSIONS

Dysfunction of the blood-brain barrier is more prominent in white-matter lesions seen in ischemic CVD than in AD and may have a role in the pathogenesis of cerebrovascular white-matter lesions.

An Italian kindred with cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL)

Vascular dementia is usually sporadic and associated with definite risk factors. Several cases also occur in a familial fashion, and may affect middle-aged or even younger subjects. Recently, an autosomal dominant inheritance was demonstrated in two unrelated French families, the members of which were affected by stroke-like episodes culminating in progressive dementia. Genetic linkage analysis assigned the disease locus to chromosome 19q12. We report an additional kindred of Italian origin in which at least 16 subjects presented leukoencephalopathic alterations. Recurrent strokes, psychiatric disturbances, dementia, and in 2 members, tetraplegia and pseudobulbar palsy were the hallmarks of this syndrome. Notably, 5 asymptomatic individuals had neuroradiological signs of leukoencephalopathy. Pathological examination of 1 subject revealed a widespread vasculopathy of the perforating arterioles, characterized by deposition of eosinophilic-congophilic material that did not immunostain with antibodies against prion protein, beta-amyloid, cystatin C, transthyretin, or heat-shock protein 70 and was similar to that described in the French families. Based on the maximum lod score, the most likely location for the disease locus was also mapped to chromosome 19q12, and found to coincide with the CADASIL (cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy) locus. The present results confirm the existence of a nosologically distinct, autosomal dominant cerebrovascular disease, presenting with recurrent subcortical ischemic strokes independent of vascular risk factors.

Small arterial granular degeneration in familial Binswanger's syndrome

A 55-year-old mildly hypertensive woman died after having developed a subcortical dementia during the past 9 years, with focal neurological signs. She presented at the age of 46 years with short episodes of dizziness and diplopia, suggesting that transient ischemic attacks involved the posterior fossa structures. Over the next 8 years, she developed difficulty in walking, urinary incontinence and seizures. On examination in 1989, she was severely demented. There was tetraparesis, bilateral arm and leg spasticity with hyperreflexia and bilateral Babinski signs. She showed epilepsia partialis continua involving the eyes, left hemiface and limbs. CT showed hypodensity of the white matter and lacunes in the basal ganglia and centrum semiovale, moderate hydrocephalus with cerebellar and cortical atrophy. Clinical and radiological features were similar to those of Binswanger's disease. Similar cases had occurred in the family affecting the patient's grandfather, father and two brothers, suggesting an autosomal dominant hereditary disease. Postmortem examination disclosed a Binswanger type of leukoencephalopathy caused by a peculiar microangiopathy characterized by a slightly basophilic small arterial granular degeneration of the medial sheath associated with the presence of ballooned smooth muscle cells with clear cytoplasm. Electron microscopic study revealed degenerative changes in the parietal vessels with notable increase of basal-membrane-type material and electron-dense granular deposits. These lesions could correspond to a specific familial pathology of the small arteries of the brain. They are identical to those reported in some patients with autosomal dominant inheritance. For other patients with similar clinical features and the same familial pattern, reported as "hereditary multi-infarct dementia'' and "chronic familial vascular encephalopathy'', there are no sufficient objective pathological facts to consider that they have the same disease.(ABSTRACT TRUNCATED AT 250 WORDS)