Clinicopathological and genetic studies of two further Italian families with cerebral autosomal dominant arteriopathy

Cognition, mood and behavior in CADASIL

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CADASIL is responsible for cognitive, mood or behavior disturbances.

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Cognitive disturbances range from moderate cognitive slowing to impairment of executive functions and may progress to a global decrease of cognitive efficiency up to severe dementia.

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Mood disturbances are extremely variable in intensity, depression is the most frequent symptom.

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Behavioral changes may occur at all stage of the disease, but are often associated with the onset of cognitive alterations. Apathy is the most prominent behavior alteration.

CADASIL is the most common familial cerebral small vessel disease (cSVD). Stereotyped mutations of the NOTCH3 gene are responsible for this archetypal ischemic cSVD that can lead, at the very end stage, to severe dementia. Variable cognitive alterations, mood, or behavior disturbances are frequently observed during the course of the disease. In this review, these clinical manifestations, their occurrence, severity and duration are analyzed in relation to the disease progression. Also, the potential relationships with cerebral lesions and treatment options are discussed.

Diagnostic criteria for CADASIL in the International Classification of Headache Disorders (ICHD-II): are they appropriate?

We reviewed the characteristics of headache in patients with cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), to verify the appropriateness of the International Classification of Headache Disorders, second edition (ICHD-II) criteria. Available data were found through Medline/PubMed using the keyword “cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL)”. The search was restricted to studies published in English in the years between 1993 and 2008. We excluded studies that did not report original data on CADASIL and information regarding the presence of headache. We found 34 studies reporting data on 749 patients overall; 387 (51.7%) patients had headache. According to the authors’ definition, 356 (92%) patients were reported as having migraine and 31 (8%) as having headache. Of the 356 patients who were defined as migraineurs, 125 (35.1%) had migraine with aura, 7 (2%) migraine without aura, 156 (43.8%) unspecified migraine and 68 (19.1%) had more than one type of migraine. Among the 31 patients reported as suffering from headache, the headache was not further detailed in 18 (58.1%) patients; it was defined as chronic in 6 (19.3%), as resembling migraine with aura in 4 (12.9%), as resembling migraine without aura in 2 (6.5%) and as tension type in 1 (3.2%) patient. In patients with CADASIL, the headache was usually referred to as migraine and mostly as migraine with aura. However, this referral is formally incorrect since the diagnostic criteria for any type of migraine in the ICHD-II require that the disturbance is not attributed to another disorder. For this reason, we suggest updating the ICHD-II in relation to CADASIL. Our suggestion is to insert a new category referred to as Headache attributed to genetic disorder including Headache attributed to CADASIL.

Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is an inherited autosomal dominant condition characterized by migrane, recurrent stroke, subcortical dementia, and pseudobulbar palsy. It begins with migraine with aura in -33% of patients. CADASIL is commonly overlooked or misdiagnosed owing to its recent identification. The pathological hallmark of angiopathy is the presence of multiple, small, deep cerebral infarcts, leucoencephalopathy, and nonatherorosclerotic, nonamyloid angiopathy involving mainly small, deep perforating cerebral arteries. Changes also are present in vascular smooth muscle cells and consist in the presence of granular osmiophilic material (GOM). The defective gene in CADASIL is Notch 3, which encodes a large transmembrane receptor. Magnetic resonance imaging shows high intensity signal lesions, often confluent, and areas of cystic degeneration of subcortical white matter and basal ganglia. Diagnostic strategies in CADASIL are matter of discussions because the electron microscopic demonstration of GOM was reported in 100% of symptomatic patients of French authors, but only in 45% of a British study. GOMs are not present in presymptomatic patients.

A chemical shift imaging study on regional metabolite distribution in a CADASIL family

A chemical shift imaging (CSI) study was performed to directly assess relative concentrations of N-acetylaspartate (NAA), Cho and Cr metabolites in normal- and abnormal-appearing brain tissue of asymptomatic and symptomatic members of a single family with a neuropathologic, genetic and electrophysiological confirmed diagnosis of cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy. The aim of the investigation was to evaluate clinical findings and metabolite abnormalities as early appearance of axonal injury in this syndrome. The main findings related statistically significant decreases in the mean metabolite ratios for NAA/Cr, NAA/Cho and Cho/Cr in the anterior parts in comparison with the posterior parts of the centrum semiovale in symptomatic and asymptomatic patients. The effect was considerably greater in the symptomatic patients, indicating a strong correlation between CSI and pathology results. No differences were found between the two areas in the control group. Although lactate signals were hardly detectable in individual spectra, there was a trend toward increased Lac/Cr values in the anterior parts with respect to the posterior parts in the patient group, with the effect particularly evident in the asymptomatic subjects with the gene mutation.

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.

Functional reorganization of motor cortex increases with greater axonal injury from CADASIL

BACKGROUND AND PURPOSE

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is an inherited small-artery disease that clinically involves only the brain. Particularly early in the disease, patients can show substantial or complete recovery after individual strokes. Cortical functional reorganization may contribute to limiting disability with such ischemic injury. We sought to test whether the extent of any functional changes in the motor cortex increases with greater brain axonal injury from CADASIL.

METHODS

Functional MRI (fMRI) was used to characterize cortical activation during a simple hand-tapping task. Disease-associated pathology in subcortical white matter was assessed with the use of conventional fluid-attenuated inversion recovery (FLAIR) MRI and MR spectroscopic imaging for measurement of N-acetyl aspartate decreases, a relatively specific measure of axonal injury.

RESULTS

There was evidence for variable but substantial hyperintense white matter signal in all of the patients with FLAIR imaging. With the use of fMRI, the brain regions activated during motor tasks were similar for the 9 CADASIL patients and 7 controls, except that most (6 of 9) patients showed primary motor cortex activation both ipsilateral and contralateral to the hand moved, a finding in only 1 of 7 healthy controls. Ipsilateral motor cortex activation increased (r=-0.77, P<0.05) and motor cortex activation lateralization index decreased (r=0.68, P<0.02) with greater white matter injury (as assessed from decreases in the relative N-acetyl aspartate concentration) in a region of interest including descending motor fibers of the corticospinal pathway.

CONCLUSIONS

The extent of functional reorganization of motor cortex increases with increasing axonal injury, consistent with an adaptive role for these changes. Increased functional recruitment of cortex ipsilateral to the limb moved therefore may contribute to limiting motor impairment from the subcortical injury of CADASIL.

Correlations between clinical findings and magnetization transfer imaging metrics of tissue damage in individuals with cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy

BACKGROUND AND PURPOSE

We obtained magnetization transfer imaging (MTI) scans from individuals with cerebral autosomal-dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) (1) to investigate the presence, extent, and nature of pathology in white and gray matter outside proton density (PD)-visible lesions; (2) to quantify the degree of tissue damage occurring in lesions seen on PD-weighted scans; and (3) to correlate MTI-derived measures of disease burden with age, physical disability, and cognitive performance.

METHODS

Dual-echo, T1-weighted, and MTI scans of the brain were obtained from 33 individuals with CADASIL and 12 control subjects. Magnetization transfer ratio (MTR) values from PD-visible lesions, normal-appearing white matter (NAWM), and normal-appearing gray matter (NAGM) were measured. Histograms of MTR from the whole brain and normal-appearing brain tissue were also produced.

RESULTS

All MTR values from NAWM and NAGM regions studied were significantly lower for individuals with CADASIL than for control subjects, with the exception of those obtained from the NAWM of the infratentorial structures and the NAGM of the occipital cortex. The average MTR from PD lesions in individuals with CADASIL was significantly lower than that from all the NAWM regions. Average MTR and peak location from whole-brain and normal-appearing brain tissue histograms were significantly lower for individuals with CADASIL than for control subjects. MTR values from NAWM were strongly correlated with the extent of macroscopic lesions and their average MTR. Apart from NAGM, average MTR from all other tissues studied significantly decreased with increasing age, physical disability, and cognitive impairment.

CONCLUSIONS

PD lesions of individuals with CADASIL have variable degrees of tissue damage. Brain tissue outside PD abnormalities is also damaged. This study suggests that the extent and the severity of the brain tissue damage are critical factors in determining clinical status in CADASIL.

An animal model for the molecular genetics of CADASIL. (Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy)

BACKGROUND

CADASIL (cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy) is an inherited condition that causes repeated small-scale strokes in adults. CADASIL is caused only by mutations in the human NOTCH3 gene that increase or decrease the number of cysteines within the epidermal growth factor (EGF) repeats of the NOTCH3 protein. Drosophila: lethal-Abruptex is a similar condition because it is also caused only by mutations that increase or decrease the number of cysteines within the EGF repeat portion of the Notch protein.

SUMMARY OF COMMENT

Drosophila: lethal-Abruptex and human CADASIL are precisely analogous at the molecular level, and both are genetically dominant. These precise similarities, together with the fact that the structure and function of Notch has been highly conserved throughout the animal kingdom, provide an animal model for the molecular and genetic aspects of human CADASIL. It also provides support for Spinner's proposal that CADASIL results from dominant inhibition of the Notch pathway.

CONCLUSIONS

Because the phenotypes of Notch mutations are cell-autonomous, the symptoms of CADASIL indicate that adult vascular smooth muscle cells require the continuing function of the NOTCH3 pathway in the adult. For this reason, further analysis of the NOTCH3 pathway may provide more general insights into the biology of vascular smooth muscle cells. In the case of CADASIL, the powerful genetic tools available in Drosophila: should help to facilitate future research.

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.

Dementia of Alzheimer type with and without multiple lacunar infarctions: evaluation of white matter lesions

The white matter lesions in dementia of Alzheimer type (DAT) with and without multiple lacunar infarctions were studied relative to a normal control group. The frequency and distribution of white matter (WM) lesions in DAT (22 cases; mean age +/- standard deviation (SD), 88.1 +/- 5.8), DAT with multiple lacunar infarctions (DAT + CVD, 18 cases; mean age +/- SD, 87.8 +/- 6.0), and in a normal control group (17 cases; mean age +/- SD, 85.2 +/- 4.8) were evaluated. The frequency of myelin pallor (frontal, parietal and occipital lobes) was significantly higher in the DAT + CVD group than in the other groups (DAT and controls). There was no significant difference in the frequency of myelin pallor between the DAT and control groups. Therefore, it was concluded that the WM lesions in DAT are the result of ischemia rather than wallerian degeneration.

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.

The phenotypic spectrum of CADASIL: clinical findings in 102 cases

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is an increasingly recognized autosomal dominant disorder that leads to cerebrovascular manifestations in early adulthood. This study delineates the phenotypic spectrum and the natural history of the disease in 102 affected individuals from 29 families with biopsy-proven CADASIL. Recurrent ischemic episodes (transient ischemic attack [TIA] or stroke) were the most frequent presentation found in 71% of the cases (mean age at onset, 46.1 years; range, 30-66 years; SD, 9.0 years). Forty-eight percent of the cases had developed cognitive deficits. Dementia (28%) was frequently accompanied by gait disturbance (90%), urinary incontinence (86%), and pseudobulbar palsy (52%). Thirty-nine patients (38%) had a history of migraine (mean age at onset, 26.0 years; SD, 8.2 years), which was classified as migraine with aura in 87% of the cases. Psychiatric disturbances were present in 30% of the cases, with adjustment disorder (24%) being the most frequent diagnosis. Ten patients (10%) had a history of epileptic seizures. To delineate the functional consequences of ischemic deficits, we studied the extent of disability in different age groups. The full spectrum of disability was seen in all groups older than age 45. Fifty-five percent of the patients older than age 60 were unable to walk without assistance. However, 14% in this age group exhibited no disability at all. Kaplan-Meier analysis disclosed median survival times of 64 years (males) and 69 years (females). An investigation of the 18 multiplex families revealed marked intrafamilial variations.

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leucoencephalopathy (CADASIL). Neuropathological and in vitro studies of abnormal elastogenesis

This study was performed on a family of CADASIL (cerebral autosomal dominant arteriopathy with subcortical infarcts and leucoencephalopathy) subjects. Neuropathological alterations of small arteries consisting in thickening, reduplication and fragmentation of the internal elastic lamella, and granular periodic acid-Schiff-positive material deposited in the arterial media were demonstrated in 1 autopsy case by histochemistry and electron microscopy. This material reacted with a monoclonal antibody anti-elastin (aE), as demonstrated by immunohistochemistry and immunoelectron microscopy. Significant increases of aE-immunoreactivity and elastin mRNA expression were found in cultured skin fibroblasts from 5 family members genetically affected by CADASIL, but not genetically and clinically healthy members. These results suggest that alterations of the elastic apparatus are associated with CADASIL genotype and related to the clinical expression of the disease.

CADASIL: a review with proposed diagnostic criteria

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) can be considered as a new disease predominantly affecting the small vessels of the brain with an autosomal dominant transmission linked to chromosome 19. This review includes an historical perspective showing how the disease was identified from the spectrum of vascular leukoencephalopathies. More than two hundred patients have now been described, belonging to at least 30 unrelated pedigrees in Europe, America and Asia. The clinical features include four major neurological presentations associated in variable degrees during the course of the disease: migraine with or without aura, strokes or stroke-like episodes, major psychiatric symptoms and dementia. The patients are free of the classical vascular risk factors. The disease has a progressive or stepwise course with age at onset in the forties and a mean duration of 13.6 +/- 10.7 years. Death occurs in the fifties in a characteristic condition associating a pseudo-bulbar syndrome and subcortical dementia. Cerebral magnetic resonance imaging (MRI) is highly contributive to the diagnosis, showing a diffuse leukoencephalopathy with subcortical infarcts in the basal ganglia and white matter. Pathological data show macroscopic lesions similar to Binswanger's disease but different lesions of the small vessels including thickening of the media, characteristic PAS+ granular material and narrowing of the lumen. Skin biopsy may be a valuable diagnostic tool, showing ultrastructural alterations of skin vessels similar to those of brain vessels. The disease is highly homogeneous on a genetic basis and the identification of the gene Notch 3 on chromosome 19 has opened new avenues for research and genetic counselling. The pathogenesis of the disease has still to be elucidated. A definite diagnosis relies on genetical or pathological data. Diagnostic criteria are proposed to recognize the disease on clinical and imaging parameters. So far, no treatment has been reported to be successful for CADASIL. Copyright Lippincott-Raven Publishers

Endothelial changes in muscle and skin biopsies in patients with CADASIL

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leucoencephalopathy (CADASIL) is characterized by the deposition of granular osmiophilic material in association with vascular smooth muscle cells in many different organs. However, the cause of the subsequent destruction of smooth muscle cells that are surrounded by granular osmiophilic material is unclear. In the present study, the ultrastructural changes that occur in endothelial cells in CADASIL have been evaluated by examining blood vessels in six skin biopsies and seven muscle biopsies belonging to three different CADASIL pedigrees. The appearances have been compared with five skin biopsies and five muscle biopsies from age-matched controls without vascular disease. The most striking features observed in vessels in the skin of CADASIL patients were attenuation of endothelial cells and increased density of endothelial cytoplasm, accompanied by the presence of compact bundles of microfilaments within the cytoplasm of endothelial cells. Endothelial cells in muscle biopsies from CADASIL patients, on the other hand, were swollen until destruction of tight junctions were observed. These findings suggest that impaired permeability of vascular endothelium may play a role in the destruction of vascular smooth muscle cells in CADASIL. Furthermore, the results of this study suggest that further fine structural investigation of blood vessel endothelium and underlying smooth muscle may lead to a better understanding of the pathophysiology of CADASIL.