The microvascular changes in cases of hereditary multi-infarct disease of the brain

Coexistence of dentatorubral-pallidoluysian atrophy and Parkinson's disease: An autopsy case report

We report an autopsy case of a 56-year-old male patient with the coexistence of dentatorubral-pallidoluysian atrophy (DRPLA) and Parkinson's disease (PD). He presented with gait instability and dysarthria for 10 years. The removed brain showed general atrophy (988 g) with depigmentation of the substantia nigra. The neocortex and deep gray matter, including the red nucleus, subthalamic nuclei, and globus pallidus, were atrophic, and grumose degeneration of the cerebellar dentate nucleus was observed. Polyglutamine- and p62-positive neuronal inclusions were present and widespread in the areas mentioned above. Interestingly, this case also had brainstem-predominant PD pathology with α-synuclein-positive Lewy bodies and Lewy neurites. Generalized white matter atrophy with patchy loss of astrocytes in the white matter suggested glial dysfunction by elongated CAG repeats in the atrophin 1 gene (atrophin 1). Polymerase chain reaction (PCR) fragment analysis revealed increased CAG repeats (61) on atrophin 1 encoding atrophin 1. The patient had a family history of DRPLA, including his daughter, who was confirmed positive on genetic testing (CAG repeat: 65). His father, brother, and niece were suspected of having the disease. Clinicopathologically, all of the above findings are consistent with the coexistence of DRPLA and PD. So far, various overlapping neurodegenerative disorders have been reported, but the coexistence of DRPLA and PD has never been demonstrated in the published literature. Even though the exact time of PD development is unknown in this case, PD might develop after DRPLA, and the overwhelming symptoms of DRPLA might mask those of PD. Here, we report a clinicopathologically definite case of the coexistence of DRPLA and PD. White matter degeneration with patchy loss of astrocytes was another remarkable finding of this case.

Update on Vascular Cognitive Impairment Associated with Subcortical Small-Vessel Disease

Subcortical small-vessel disease (SSVD) is a disorder well characterized from the clinical, imaging, and neuropathological viewpoints. SSVD is considered the most prevalent ischemic brain disorder, increasing in frequency with age. Vascular risk factors include hypertension, diabetes, hyperlipidemia, elevated homocysteine, and obstructive sleep apnea. Ischemic white matter lesions are the hallmark of SSVD; other pathological lesions include arteriolosclerosis, dilatation of perivascular spaces, venous collagenosis, cerebral amyloid angiopathy, microbleeds, microinfarcts, lacunes, and large infarcts. The pathogenesis of SSVD is incompletely understood but includes endothelial changes and blood-brain barrier alterations involving metalloproteinases, vascular endothelial growth factors, angiotensin II, mindin/spondin, and the mammalian target of rapamycin pathway. Metabolic and genetic conditions may also play a role but hitherto there are few conclusive studies. Clinical diagnosis of SSVD includes early executive dysfunction manifested by impaired capacity to use complex information, to formulate strategies, and to exercise self-control. In comparison with Alzheimer's disease (AD), patients with SSVD show less pronounced episodic memory deficits. Brain imaging has advanced substantially the diagnostic tools for SSVD. With the exception of cortical microinfarcts, all other lesions are well visualized with MRI. Diagnostic biomarkers that separate AD from SSVD include reduction of cerebrospinal fluid amyloid-β (Aβ)42 and of the ratio Aβ42/Aβ40 often with increased total tau levels. However, better markers of small-vessel function of intracerebral blood vessels are needed. The treatment of SSVD remains unsatisfactory other than control of vascular risk factors. There is an urgent need of finding targets to slow down and potentially halt the progression of this prevalent, but often unrecognized, disorder.

Acupuncture with reinforcing and reducing twirling manipulation inhibits hippocampal neuronal apoptosis in spontaneously hypertensive rats

To observe the effects of different acupuncture manipulations on blood pressure and target organ damage in spontaneously hypertensive rats (SHRs), this study used the reinforcing twirling method (1.5–2-mm depth; rotating needle clockwise for 360° and then counter clockwise for 360°, with the thumb moving heavily forward and gently backward, 60 times per minute for 1 minute, and retaining needle for 9 minutes), the reducing twirling method (1.5–2-mm depth; rotating needle counter clockwise for 360° and then clockwise for 360°, with the thumb moving heavily backward and gently forward, 60 times per minute for 1 minute, and retaining needle for 9 minutes), and the needle retaining method (1.5–2-mm depth and retaining the needle for 10 minutes). Bilateral Taichong (LR3) was treated by acupuncture using different manipulations and manual stimulation. Reinforcing twirling, reducing twirling, and needle retaining resulted in a decreased number of apoptotic cells, reduced Bax mRNA and protein expression, and an increased Bcl-2/Bax ratio in the hippocampus compared with the SHR group. Among these groups, the Bcl-2/Bax protein ratio was highest in the reducing twirling group, and the Bcl-2/Bax mRNA ratio was highest in the needle retaining group. These results suggest that reinforcing twirling, reducing twirling, and needle retaining methods all improve blood pressure and prevent target organ damage by increasing the hippocampal Bcl-2/Bax ratio and inhibiting cell apoptosis in the hippocampus in SHR.

Bilateral Focal Cerebral Angiomatosis Associated with Nervous Signs in a Cat

A case of cerebral angiomatosis in a cat was associated with neurologic signs characterized by clusters of severe generalized seizures. Bilaterally in the gray matter, most prominent in the cingulate gyrus, there was focal accumulation of garlandlike arrangements of blood vessels. Vessels exhibited activated, hypertrophic endothelial cells and thickening and progressive dystrophic mineralization of the basement membrane, with complete luminal obstruction of some affected vessels. Thickening of the basement membrane was due to accumulation of endothelium-derived proteins such as laminin and von Willebrand factor. Furthermore, moderate diffuse astrogliosis was observed. Findings indicate an idiopathic angiomatosis, with clinical signs possibly due to ischemia resulting from narrowing or complete obliteration of vessel lumina. Changes represent a unique endothelial cell-derived lesion within the brain not previously described in humans or domestic animals.

Microvascular pathology and morphometrics of sporadic and hereditary small vessel diseases of the brain

Small vessel diseases (SVDs) of the brain are likely to become increasingly common in tandem with the rise in the aging population. In recent years, neuroimaging and pathological studies have informed on the pathogenesis of sporadic SVD and several single gene (monogenic) disorders predisposing to subcortical strokes and diffuse white matter disease. However, one of the limitations toward studying SVD lies in the lack of consistent assessment criteria and lesion burden for both clinical and pathological measures. Arteriolosclerosis and diffuse white matter changes are the hallmark features of both sporadic and hereditary SVDs. The pathogenesis of the arteriopathy is the key to understanding the differential progression of disease in various SVDs. Remarkably, quantification of microvascular abnormalities in sporadic and hereditary SVDs has shown that qualitatively the processes involved in arteriolar degeneration are largely similar in sporadic SVD compared with hereditary disorders such as cerebral autosomal arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL). Important significant regional differences in lesion location within the brain may enable one to distinguish SVDs, where frontal lobe involvement appears consistently with almost every SVD, but others bear specific pathologies in other lobes, such as the temporal pole in CADASIL and the pons in pontine autosomal dominant microangiopathy and leukoencephalopathy or PADMAL. Additionally, degenerative changes in the vascular smooth muscle cells, the cerebral endothelium and the basal lamina are often rapid and more aggressive in genetic disorders. Further quantification of other microvascular elements and even neuronal cells is needed to fully characterize SVD pathogenesis and to differentiate the usefulness of vascular interventions and treatments on the resulting pathology.

Long-Term Stimulation with Electroacupuncture at DU20 and ST36 Rescues Hippocampal Neuron through Attenuating Cerebral Blood Flow in Spontaneously Hypertensive Rats

This study was designed to investigate the effect of long-term electroacupuncture at Baihui (DU20) and Zusanli (ST36) on cerebral microvessels and neurons in CA1 region of hippocampus in spontaneously hypertensive rats (SHR). A total of 45 male Wistar rats and 45 SHR were randomly grouped, with or without electroacupuncture (EA) at DU20 and ST36, once every other day for a period of 8 weeks. The mean arterial pressure (MAP) was measured once every 2 weeks. Cerebral blood flow (CBF) and the number of open microvessels in hippocampal CA1 region were detected by Laser Doppler and immunohistochemistry, respectively. Nissl staining and Western blotting were performed, respectively, to determine hippocampus morphology and proteins that were implicated in the concerning signaling pathways. The results showed that the MAP in SHR increased linearly over the observation period and was significantly reduced following electroacupuncture as compared with sham control SHR rats, while no difference was observed in Wistar rats between EA and sham control. The CBF, learning and memory capacity, and capillary rarefaction of SHR were improved by EA. The upregulation of angiotensin II type I receptor (AT1R), endothelin receptor (ETAR), and endothelin-1 (ET-1) in SHR rats was attenuated by electroacupuncture, suggesting an implication of AT1R, ETAR, and ET-1 pathway in the effect of EA.

Quantitative vascular pathology and phenotyping familial and sporadic cerebral small vessel diseases

We quantified vascular changes in the frontal lobe and basal ganglia of four inherited small vessel diseases (SVDs) including cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), pontine autosomal dominant microangiopathy and leukoencephalopathy (PADMAL), hereditary multi-infarct dementia of Swedish type (Swedish hMID), and hereditary endotheliopathy with retinopathy, nephropathy, and stroke (HERNS). Vascular pathology was most severe in CADASIL, and varied with marginally greater severity in the basal ganglia compared to the frontal lobe. The overall sclerotic index values in frontal lobe were in the order CADASIL ≥ HERNS > PADMAL > Swedish hMID > sporadic SVD, and in basal ganglia CADASIL > HERNS > Swedish hMID > PADMAL> sporadic SVD. The subcortical white matter was almost always more affected than any gray matter. We observed glucose transporter-1 (GLUT-1) protein immunoreactivities were most affected in the white matter indicating capillary degeneration whereas collagen IV (COL4) immunostaining was increased in PADMAL cases in all regions and tissue types. Overall, GLUT-1 : COL4 ratios were higher in the basal ganglia indicating modifications in capillary density compared to the frontal lobe. Our study shows that the extent of microvascular degeneration varies in these genetic disorders exhibiting common end-stage pathologies but is the most aggressive in CADASIL.

Aging-related kidney damage is associated with a decrease in klotho expression and an increase in superoxide production

The purpose of this study was to determine changes in klotho, endothelin (ET) receptors, and superoxide production in kidneys of aged rats and whether these changes are exacerbated in aged rats with cognitive impairment. Twenty aged rats (male, 27 months) were divided into an Old Impaired group (n=9) and an Old Intact group (n=11) according to a cognitive function test. A group of 12-month-old rats (n=10) was used as a Young Intact group. Serum creatinine was increased significantly in the Old Impaired group, suggesting impaired renal function. Aged rats showed glomerulosclerosis and tubulointerstitialfibrosis. These pathological changes were markedly aggravated in the old cognitively impaired than in the old cognitively intact animals. Notably, aged rats demonstrated a significant decrease in klotho protein expression in renal cortex and medulla. Protein expression of IL-6, Nox2, ETa receptors and superoxide production were increased whereas mitochondrial SOD (MnSOD) and ETb receptors expression were decreased in kidneys of the aged rats. Interestingly, these changes were more pronounced in the old impaired than in the old intact rats. In conclusion, the aging-related kidney damage was exacerbated in aged rats with cognitive impairment. Klotho, ETB, and MnSOD were downregulated but ETa, IL-6, Nox2, and superoxide production were upregulated in the aging-related kidney damage. These changes were more pronounced in rats with cognitive impairment.

White matter disorders with autosomal dominant heredity: a review with personal clinical case studies and their MRI findings

BACKGROUND

Leukoencephalopathies are a heterogeneous group of severe encephalopathy syndromes with myelin, axonal or vascular pathology, typically with extensive white matter lesions on MRI T2-FSE and/or -FLAIR sequences.

OBJECTIVES

This review is restricted to leukoencephalopathies with onset in adult age and a dominant inheritance. These diseases are generally severe and often lethal and present with an exacerbating or insidiously progressive course.

MATERIAL AND METHODS

The focus is on four syndromes with pure leukoencephalopathies, however, leukoencephalopathies with associated clinical features are included.

RESULTS

T2 weighted MR imaging often show features common for leukoencephalopathies, yet shows distinguishing features in transthyretin amyloidosis.

CONCLUSION

The diagnosis within the group of leukoencephalopathies thus characterized by MRI relies mainly upon clinical and genetic analysis. The differential diagnosis against treatable leukoencephalopathies is increasingly relevant.

CADASIL: pathogenesis, clinical and radiological findings and treatment

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is the most common genetic cause of ischemic strokes and a most important model for the study of subcortical vascular dementia. This unrelentlessly progressive disease affects many hundreds of families all over the world but is not well studied in Brazil. This manuscript reviews pathogenetic, clinical, radiological and therapeutic features of CADASIL. The causal mutations are now very well known, but the same can not be said about its intimate pathogenetic mechanisms. The variable clinical presentation should lead physicians to actively pursue the diagnosis in many settings and to more thouroughly investigate family history in first degree relatives. A rational approach to genetic testing is however needed. Treatment of CADASIL is still largely empiric. High-quality therapeutic studies involving medications and cognitive interventions are strongly needed in CADASIL.

Neuropsychiatric manifestations in CADASIL

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is an inherited small-artery disease of mid-adulthood caused by mutations of the NOTCH3 gene. The disease is responsible for widespread white-matter lesions associated with lacunar infarctions in various subcortical areas. The disease is responsible for migraine with aura and ischemic strokes, and is associated with various degrees of cognitive impairment and with mood disturbances. CADASIL is considered as a unique model to investigate what is known as "subcortical ischemic vascular dementia." Recent data suggest that the number of lacunar infarctions and severity of cerebral atrophy are the main magnetic resonance imaging markers associated with cognitive and motor disabilities in this disorder. Mood disturbances are reported in 10% to 20% of patients, most often in association with cognitive alterations. Their exact origin remains unknown; the presence of ischemic lesions within the basal ganglia or the frontal white matter may promote the occurrence of these symptoms. Further studies are needed to better understand the relationships between cerebral lesions and both cognitive and psychiatric symptoms in this small-vessel disease of the brain.

Mechanisms of target organ damage caused by hypertension: therapeutic potential

Hypertension is a major risk factor for cardiovascular mortality and morbidity through its effects on target organs like the brain, heart, and kidney. Structural alterations in the microcirculation form a major link between hypertension and target organ damage. In this review, we describe damages related to hypertension in these target organs and the mechanisms involved in the pathogenesis of hypertension-induced cardiovascular diseases such as dementia, cardiac ischemia and remodeling, or nephropathy. We also focus on the therapeutical potential on the basis of such mechanisms. Several antihypertensive agents like diuretics, angiotensin converting enzyme (ACE) inhibitors, angiotensin II (Ang II) receptor antagonists, beta-blockers, or calcium channel blockers (CCBs) have been shown to reduce effectively hypertension associated cardiovascular events and to improve end organ damage. More recently, aldosterone antagonism has also shown beneficial effects. Part of the favorable effects of these agents is due to blood pressure lowering as such. Other mechanisms such as oxidative stress, inflammation, or endothelial dysfunction have appeared to play a key role in the pathogenesis of target organ damage and therefore represent another important pathway for therapy. In this review, we discuss the different therapeutic approaches aiming at reducing cardiovascular events and damages induced by hypertension.

CADASIL: what component of the vessel wall is really a target for Notch 3 gene mutations?

Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy (CADASIL) is a hereditary cerebrovascular disease leading to cognitive decline, dementia and recurrent strokes. The underlying angiopathy of the small vessels is characterized by basophilic degeneration of the media, Notch 3 protein accumulation in vessel wall and a unique type of ultrastructural deposits located nearby the basal lamina. In some cases of CADASIL, morphological changes similar to those observed in panarteritis nodosa (PAN) were found. PAN-like changes manifested as fibrinoid necrosis of the tunica media and perivascular inflammatory infiltrates were found in arteries not only in the central nervous system but also in internal organs. Presence of PAN-like changes indicates that some autoimmunological mechanisms can participate in the CADASIL process. Although vascular smooth muscle cells seem to be a primary target of the pathogenic process triggered by mutations in Notch 3 gene they are probably not the only target. This article gives a brief overview on the morphologic spectrum of the vascular pathological changes in CADASIL and discusses some of the relevant mechanisms that lead from Notch 3 mutations to ischemic infarcts.

Glycohistochemical characterization of vascular muscle cell destruction in CADASIL subjects by lectins, neoglycoconjugates and galectin-specific antibodies

CADASIL (Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy) is a type of small-artery stroke and vascular dementia-inducing pathology of the brain. In order to explain the molecular mechanisms behind the alterations to the blood vessels in CADASIL subjects, we scrutinized the expression of glycan and glycan-binding sites in the wall of vessels taken from five such subjects (vs. five control subjects matched for age and sex). Specimens were taken from the brain, heart, kidney, liver and lung. Although the main vessel lesions were observed in the tissues depending on the blood-brain barrier, alterations to systemic vessels were also observed despite the absence of any symptoms. The histochemical expression of a panel of 10 biotinylated neoglycoconjugates [Gal-beta(1-4)-D-Glc, Galbeta(1-3)GalNAc, alpha-D-GalNAc, beta-D-GalNAc, GalNAcalpha(1-3)-D-GalNAcalpha, GalNAcalpha(1-3)-D-GalNAcbeta, beta-D-Glc, alpha-D-Man, l-Fucose and D-Glcalpha(1-4)-D-Glc], eight plant lectins (PNA, MAA, SNA, DBA, WGA, ConA, GNA and UEA-1) and two antigalectin antibodies was monitored by means of semiquantitative and quantitative computer-assisted microscopy. The data show the altered histochemical binding of plant lectins, such as UEA-1 and ConA, in the vessel walls of CADASIL subjects. The present work, based upon staining by a panel of neoglycoconjugates, provides a biochemical characterization of the alteration of vessel walls in the brain compared to other organs including the heart, kidney, lung and liver in CADASIL as opposed to control subjects. These glycohistochemical results suggest a functional relevance of protein-carbohydrate interactions in this disease.

CADASIL and genetics of cerebral ischaemia

Recent advances suggest the existence of several autosomal dominantly inherited forms of cerebrovascular disorders. Mutations in diverse genes may induce direct pathological changes in intracranial vessels to cause cerebral ischaemic or haemorrhagic strokes leading to cognitive impairment and dementia. Similar pathology may also be caused by systemic vascular disease resulting from mutations and polymorphisms in genes that regulate cardiovascular physiology, blood coagulation and metabolic functions. The most common form of familial stroke appears to be CADASIL or cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy. CADASIL is an arterial disease that has been linked to nucleotide substitutions and deletions in the Notch 3 gene. The pathogenesis of the disorder or how the mutations lead to cerebral infarcts and dementia is not known. However, elucidation of the microvascular pathology associated with such genetic disorders not associated with physiological risk factors for cardiovascular disease or stroke can bear much light on primary vascular mechanisms that lead to ischaemic blood flow and neuronal vulnerability.

Prolonged cerebral transit time in CADASIL: a transcranial ultrasound study

BACKGROUND AND PURPOSE

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a hereditary angiopathy caused by mutations in Notch3. Cerebral microvessels show an accumulation of granular osmophilic material in the vicinity of degenerating vascular smooth muscle cells. In this study, we measured the arteriovenous cerebral transit time (CTT) to identify changes related to the microangiopathy in CADASIL.

METHODS

CTT is the time that a contrast agent needs to pass from a cerebral artery to its corresponding vein. CTT was measured in 17 CADASIL individuals (mean age, 50.2+/-12.3 years) and an equal number of age- and sex-matched control subjects (mean age, 48.9+/-13.0 years) with transcranial color-coded duplex sonography. The intensity curves were recorded in the P2 segment of the posterior cerebral artery and the vein of Galen after injection of the ultrasound contrast agent Levovist.

RESULTS

CTT was significantly prolonged in individuals with CADASIL (4.4+/-1.9 seconds) compared with control subjects (1.3+/-0.5 seconds, P<0.0001). This difference was also significant when only nondisabled CADASIL individuals (Rankin score=0, n=9) were analyzed (P<0.0001). There was a nonsignificant trend for a correlation between Rankin score and CTT (r=0.39, P=0.11).

CONCLUSIONS

The prolonged CTT likely reflects microvascular changes in CADASIL. Measurements of the CTT may be used clinically to disclose small-vessel disease. Studies comparing CADASIL subjects with other patient populations seem warranted to determine possible differences in CTT between different types of small-vessel disease.

Chronic cerebral hypoperfusion induces MMP-2 but not MMP-9 expression in the microglia and vascular endothelium of white matter

White matter lesions are closely associated with cognitive impairment and motor dysfunction in the aged. To explore the pathophysiology of these lesions, the authors examined the expression of matrix metalloproteinase-2 (MMP-2) and MMP-9 in the white matter in a rat model of chronic cerebral hypoperfusion. After bilateral clipping of the common carotid arteries, myelin staining revealed demyelinating changes in the optic tract and the corpus callosum on day 7. Zymographic analyses indicated an increase in the level of MMP-2, but not MMP-9, after the hypoperfusion. Immunohistochemical analyses revealed the presence (most abundantly on day 3) of MMP-2-expressing activated microglia in the optic tract and corpus callosum. In contrast, the capillary endothelial cells expressed MMP-2 later. IgM-immunoreactive glial cells were absent in the sham-operated animals, but were present in the hypoperfused animals by day 3, reflecting the disrupted blood-brain barrier. These findings suggest that the main sources of the elevated MMP-2 were the microglia and the endothelium, and that these cells may contribute to the remodeling of the white matter myelin and microvascular beds in chronic cerebral hypoperfusion.

Advances in molecular genetics and pathology of cerebrovascular disorders

Progress in molecular genetics has enabled the dissection of several autosomal dominantly inherited forms of cerebrovascular disorders. Mutations in diverse genes might induce pathological changes in intracranial vessels, resulting in cerebral haemorrhages and ischaemic strokes. Such pathologies, however, might also result from systemic vascular disease caused by mutations or polymorphisms in genes that regulate cardiovascular physiology, blood coagulation, lipid metabolism and metabolic functions. Interestingly, several mutations that directly affect CNS vasculature involve genes that control inter- or intracellular signalling functions. Although highly variable phenotypes make it difficult to pinpoint the genotypes, genetic characterization of cerebrovascular disorders is valuable for understanding the pathogenesis and management of sporadic disease.

Visual electrophysiological responses in subjects with cerebral autosomal arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL)

OBJECTIVES

To evaluate visual electrophysiological responses in subjects with cerebral autosomal arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL).

METHODS

Three subjects (one male and two females, mean age 55.3+/-2.9 years) belonging to an Italian family already diagnosed with CADASIL through clinicopathological and genetic studies and 14 control subjects (6 males and 8 females, mean age 52.7+/-3.6 years) were enrolled in the study. Flash electroretinogram (ERG), oscillatory potentials (OPs) and simultaneous recordings of pattern electroretinogram (PERG) and visual evoked potentials (VEPs) were assessed in all 3 subjects with CADASIL and age-matched controls.

RESULTS

Subjects with CADASIL showed: reduced ERG, OP and PERG (N35-P50, P50-N95) amplitudes with respect to our normal limits; delayed PERG (N35, P50) and VEP (P100) implicit times when compared with our normal limits; and VEP (N75-P100) amplitudes and retinocortical times within our normal limits.

CONCLUSIONS

Subjects with CADASIL present a dysfunction in the outer, middle and innermost retinal layers when the index of neural conduction in the postretinal visual pathways is normal. The delay in visual cortical responses observed in subjects with CADASIL may be ascribable to retinal impairment with a possible functional sparing of the postretinal visual structures.

Cerebral hemodynamics in CADASIL before and after acetazolamide challenge assessed with MRI bolus tracking

BACKGROUND

White matter lesions in cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) are underlaid by severe ultrastructural changes of the arteriolar wall. Although chronic ischemia is presumed to cause the tissue lesions, the pattern of perfusion abnormalities and hemodynamic reserve in CADASIL, particularly within the white matter, remains unknown.

METHODS

We used the MRI bolus tracking method in 15 symptomatic patients with CADASIL (5 with dementia) and 10 age-matched control subjects before and 20 minutes after the intravenous injection of acetazolamide (ACZ, 17 mg/kg). Cerebral blood flow (CBF), blood volume (CBV), and mean transit time (MTT) were calculated both in the cortex and in the white matter according to the singular value decomposition technique. Perfusion parameters were obtained in regions of hyperintensities and within the normal-appearing white matter as observed on T2-weighted images. Analysis was performed with both absolute and relative (region/whole brain) values.

RESULTS

A significant reduction in absolute and relative CBF and CBV was found within areas of T2 hyperintensities in white matter in the absence of significant variations of MTT. This reduction was more severe in demented than in nondemented patients. No significant change in absolute CBF and CBV values was observed in the cortex of patients with CADASIL. A decrease in relative CBF and CBV values was detected in the occipital cortex. After ACZ administration, CBF and CBV increased significantly in both the cortex and white matter of affected subjects, but the increase in absolute CBF was lower within areas of increased signal on T2-weighted images in patients than in the white matter of control subjects.

CONCLUSIONS

In CADASIL, both basal perfusion and hemodynamic reserve are decreased in areas of T2 hyperintensities in the white matter. This hypoperfusion appears to be related to the clinical severity. The significant effect of ACZ on CBF and CBV suggests that cerebral perfusion might be increased using pharmacological vasodilation in CADASIL.

The natural history of CADASIL: a pooled analysis of previously published cases

BACKGROUND AND PURPOSE

Although numerous families with cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) have been reported, our understanding of the disease remains incomplete. Thus, we performed this study to investigate the phenotypic range and natural history of CADASIL.

METHODS

We performed a pooled analysis of previously published cases.

RESULTS

We identified 105 symptomatic patients in 33 families. Vascular risk factors were uncommon, with hypertension reported in only 8 patients. The mean age of symptom onset was 36. 7+/-12.9 years. Stroke or transient ischemic attack was an initial symptom in 45 patients, with a mean age of onset of 41.2+/-9.2 years. Migraine was also a common initial symptom, reported by 42 patients at a younger mean age of 28.3+/-11.7 years. Other initial symptoms included depression in 9 patients, cognitive impairment in 6 patients, and seizures in 3 patients. Regarding clinical course, 71 patients experienced a stroke or transient ischemic attack, and 52 of those patients had 1 or more recurrent ischemic events. Dementia was reported in 44 patients. Only 3 additional patients experienced migraine at a later time, while 13 additional patients developed depression. Six patients had seizures. Twenty-two of the 105 patients had died, with a mean age of death of 54.8+/-10.6 years. Nineteen of those 22 patients had experienced a stroke or transient ischemic attack and 19 patients were demented.

CONCLUSIONS

CADASIL typically becomes evident in early or middle adulthood with migraine or an ischemic event, later manifests itself through recurrent subcortical ischemic strokes leading to a stepwise decline and dementia, and results in reduced survival.

Cerebral vessels in ageing and Alzheimer's disease

The integrity of the cerebral vasculature is crucial to the maintenance of cognitive functions during ageing. Prevailing evidence suggests that cerebrovascular functions decline during normal ageing, with pronounced effects in Alzheimer's disease (AD). The causes of these changes largely remain unknown. While previous studies recorded ageing-related impairments, such as atherosclerosis and loss of innervation in basal surface arteries of the brain, it only recently has been realized that a number of subtle alterations in both the intracranial resistance vessels and the smaller capillaries is apparent in both ageing animals and humans. The dominant changes include alterations in composition of connective tissues and smooth muscle of large vessel walls, thickening of the vascular basement membrane, thinning of the endothelium in some species, loss of endothelial mitochondria and increased pericytes. Some of these attributes appear more affected in AD. Other abnormalities entail profound irregularities in the course of microvessels, unexplained inclusions in the basement membrane and changes in unique proteins and membrane lipids associated with the blood-brain barrier. Brain imaging and permeability studies show no clear functional evidence to support the structural and biochemical anomalies, but it is plausible that focal and transient breach of the blood-brain barrier in ageing, and more notably in AD, occurs. Thus, circumscribed neuronal populations in certain brain regions could become vulnerable. Furthermore, the characteristic deposition of amyloid in vessels in AD may exacerbate the decline in vascular function and promote chronic hypoperfusion. Although not explicit from current studies, it is likely that the brain vasculature is continually modified by growth and repair mechanisms in attempts to maintain perfusion during ageing and disease.

Autosomal dominant early onset dementia and leukoencephalopathy in a Japanese family: clinical, neuroimaging and genetic studies

We report here the results of clinical, neuroimaging and genetic studies of autosomal dominant dementia and leukoencephalopathy in a Japanese family. Twenty-two individuals in this family were examined clinically (17 living, 5 deceased), neuroradiologically and genetically (16 of 17 living members). Ten (5 deceased) of 22 individuals had early onset dementia (age of onset: 45.2 +/- 12.1 years on average) and four of them had multiple white matter lesions and brain atrophy on brain MRI without history of brain ischemic attack. Another four individuals had abnormal white matter lesions on brain MRI without dementia. Linkage studies for chromosome 1q31-42, 14q24.3 and 21q21 responsible for Alzheimer's disease, chromosome 19p13.1-13.2 for cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) and chromosome 3 for familial non-specific dementia suggested no specific haplotypes cosegregated with the disease. Apo E genotypes were E2/2 and E2/3 in this family. Clinical, neuroimaging and genetic studies revealed that the disease in this family was distinguished from known familial dementia. This is the first report of a large Japanese family with autosomal dominant early onset dementia and leukoencephalopathy.

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.

A four-generation Dutch family with cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), linked to chromosome 19p13

We describe a four-generation Dutch family suffering from cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL). Of twenty affected family members, ten are still alive. Age at onset of the strokes was between 29 and 52 years, with a mean of 41.8 years. This family has the typical clinical and radiological features of CADASIL (except for the occurrence of ischemic heart disease at a relatively young age in some subjects), and is linked to chromosome 19p13. This disease has so far been described in families from Finland, France, Germany, Italy, Japan, Spain and the United Kingdom, and there is a remarkable clinical and genetical homogeneity among all families reported, including this Dutch family.

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.

Identification of the characteristic vascular changes in a sural nerve biopsy of a case with cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL)

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy' (CADASIL) has recently been identified as a hereditary disorder with characteristic fine structural changes of small intracerebral arteries and arterioles. Electron microscopically there are characteristic perivascular deposits of granular electron-dense material resembling immunoglobulin deposits. The present case from a family with four affected members in three successive generations shows that similar vascular changes as described in the central nervous system are present in blood vessels of the sural nerve, although less pronounced and, therefore, affording electron microscopy for their unequivocal detection. Nevertheless it has been shown for the first time that the diagnosis of CADASIL can be verified by a sural nerve biopsy. Occasional focal accumulation of pinocytotic vesicles opposite the granular deposits suggests exocytosis as one of the possible pathomechanisms for their production.

Systemic vascular smooth muscle cell impairment in cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is characterized by a cerebral non-atherosclerotic, nonamyloid angiopathy mainly affecting the small arteries penetrating the white matter. In the brain vessels of two patients with CADASIL, abnormal patches of granular osmiophilic material have recently been described. Here we report the observation of similar granular osmiophilic material within the vessel walls of muscle and skin biopsies from a 54-year-old woman belonging to a CADASIL family, who suffered from subcortical dementia with leukoencephalopathy demonstrated on neuroimaging. Postmortem examination disclosed changes of the vessel walls in all the organs chiefly leading to cerebral lesions. Ultrastructural study showed destruction of the vascular smooth muscle cells (VSMC) and the granular osmiophilic material already found in muscle and skin biopsies in this patient. Both changes were found all along the arterial tree. The findings of this study indicate that CADASIL is a systemic vascular disease involving arterial VSMC and that the lesions are different in each organ and vessel wall, depending on their fine structure. Moreover, it emphasizes that skin and muscle biopsies might be useful for diagnosis of and research into CADASIL.

In memory of Patrick Sourander (1917-1993)

Patrick Sourander was the Professor of Neuropathology at the University of Göteborg, Sweden, who died on September 28, 1993. His scientific interests focused on metabolic disturbances, in particular leucodystrophies, lipidosis and the consequences of malnutrition. He was the co-discoverer of an inherited cerebrovascular disease now termed CADASIL (cerebral autosomal dominant arteriopathy with subcortical infarcts and leuokoencephalopathy). Earlier than many contemporary neuropathologists, Patrick Sourander realized the potential of a close cooperation between basic neurobiology and clinical investigations. As a founding member of the International Society of Neuropathology, Patrick held the office of Vice-President during 1974-1978 and was the President of the Xth International Congress of Neuropathology held in Stockholm, in 1986.