Francesca Pescini

Comparison of clinical, familial, and MRI features of CADASIL and NOTCH3-negative patients

Objective: To report the characteristics of patients suspected to have cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) but in whom no NOTCH3 gene pathogenic mutation was found. Methods: Between 2002 and 2008, we performed NOTCH3 gene analysis (exons 2–23) in 81 probands because CADASIL was clinically suspected. A retrospective analysis and comparison of clinical, familial, and neuroimaging features of patients with and without pathogenic mutations was performed. Results: CADASIL was diagnosed in 16/81 (20%) probands by finding a mutation leading to a cysteine substitution within the epidermal growth factor (EGF)–like repeats of the NOTCH3 receptor. In the remaining 65 patients, no pathogenic mutation was found. Some features were significantly (Fisher exact test p < 0.05) more frequent in CADASIL than in NOTCH3-negative patients: history of migraine (73 vs 39%), stroke before the age of 60 among relatives (71 vs 32%), severe leukoencephalopathy (94 vs 62%), white matter changes extended to the anterior temporal lobes (93 vs 45%), external capsule involvement (100 vs 50%), and presence of lacunar infarcts (100 vs 65%). The frequency of vascular risk factors was balanced between the 2 groups. No feature was peculiar to either group. Conclusions: Although certain clinical and neuroimaging features are more frequent in cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) than in NOTCH3-negative patients, none is pathognomonic. Clinicians should be aware that when diagnosing CADASIL, a number of patients with a cerebral disease phenotypically similar to CADASIL emerge. The genetic profile of these diseases and the full phenotypic difference with CADASIL remain to be further defined.

Circulating biologic markers of endothelial dysfunction in cerebral small vessel disease: a review

The term cerebral small vessel disease (SVD) refers to a group of pathologic processes with various etiologies that affect small arteries, arterioles, venules, and capillaries of the brain. Magnetic resonance imaging (MRI) correlates of SVD are lacunes, recent small subcortical infarcts, white-matter hyperintensities, enlarged perivascular spaces, microbleeds, and brain atrophy. Endothelial dysfunction is thought to have a role in the mechanisms leading to SVD-related brain changes, and the study of endothelial dysfunction has been proposed as an important step for a better comprehension of cerebral SVD. Among available methods to assess endothelial function in vivo, measurement of molecules of endothelial origin in peripheral blood is currently receiving selective attention. These molecules include products of endothelial cells that change when the endothelium is activated, as well as molecules that reflect endothelial damage and repair. This review examines the main molecular factors involved in both endothelial function and dysfunction, and the evidence linking endothelial dysfunction with cerebral SVD, and gives an overview of clinical studies that have investigated the possible association between endothelial circulating biomarkers and SVD-related brain changes.

Psychiatric disturbances in CADASIL: a brief review.

Background –  Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is an inherited cerebrovascular disease, clinically characterized by a variable combination of migraine, recurrent transient ischemic attack (TIA) or lacunar strokes, cognitive decline, and mood disturbances. However, the assessment of psychiatric disturbances in this disease has never been carried out systematically.

The Cerebral Autosomal-Dominant Arteriopathy With Subcortical Infarcts and Leukoencephalopathy (CADASIL) Scale: a screening tool to select patients for NOTCH3 gene analysis.

Background and Purpose— Cerebral autosomal-dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) phenotype is highly variable, and, although the full clinical–neuroimaging picture may be suggestive of the disease, no characteristic is pathognomonic. Thus, a genetic test remains the diagnostic gold standard, but because it is costly and time-consuming, a pregenetic screening appears desirable. We aimed at developing the CADASIL scale, a screening tool to be applied in the clinical setting. Methods— A preliminary scale was created assigning weighted scores to common disease features based on their frequencies obtained in a pooled analysis of selected international CADASIL series. The accuracy of the scale versus the genetic diagnosis was tested with receiver operating characteristic analysis after the application of this scale to 61 CADASIL and 54 NOTCH3-negative patients (no pathogenic mutation on exons 2–23 of the NOTCH3 gene). To improve the scale accuracy, we then developed an ad hoc optimization algorithm to detect the definitive scale. A third group of 39 patients affected by sporadic small-vessel disease was finally included in the algorithm to evaluate the stability of the scale. Results— The cutoff score of the definitive CADASIL scale had a sensitivity of 96.7% and a specificity of 74.2%. This scale was robust to contamination of patients with sporadic small-vessel disease. Conclusions— The CADASIL scale is a simple and sufficiently accurate screening tool to select patients with a high probability to be affected by the disease and therefore to be subjected to the genetic testing.

Cerebral hemorrhages in CADASIL: report of four cases and a brief review.

BACKGROUND Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is an inherited cerebral small vessel disease, clinically characterized by migraine, recurrent transient ischemic attacks or strokes, psychiatric disorders and cognitive decline. Strokes are typically ischemic, while hemorrhagic events have been only sporadically described. However, cerebral microbleeds have been found in 31-69% of CADASIL patients. METHODS We describe four unrelated CADASIL patients who had hemorrhagic strokes. We also briefly review the literature on intracerebral hemorrhage (ICH) in CADASIL. RESULTS Three patients had a thalamo-capsular hemorrhage (age at onset: 54, 67, 77) and one of these had a second hemispheric cerebellar hemorrhage. Another patient experienced an interpeduncular cistern subarachnoid hemorrhage when he was 39. None of these patients was receiving antiplatelets, anticoagulants or statins at the time of hemorrhage; all were hypertensive. NOTCH3 gene analysis revealed mutations on exons 14, 22 (two patients presenting the same mutation), and 24. MRI signs of previous hemorrhages were present in all these patients. CONCLUSIONS Hemorrhagic stroke can occur in CADASIL similarly to sporadic cerebral small vessel diseases; this finding expands the phenotype of the disease. A diagnosis of CADASIL should probably be considered also in patients with ICH. These data bear potential implications in terms of need of better control of risk factors, particularly hypertension, and raise relevant questions about the use of antiplatelets as prevention measures in CADASIL patients.

A pathogenic mutation on exon 21 of the NOTCH3 gene causing CADASIL in an octogenarian paucisymptomatic patient.

CADASIL (Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy) is an inherited small vessel disease causing migraine, early strokes, cognitive impairment and premature death. The disease is caused by NOTCH3 gene puntiform mutations on one of the exons coding for the epidermal-growth factor (EGF)-like repeats of the extracellular domain of the NOTCH3 receptor. Mutations have been reported with higher frequency on some exons, and never on 6 out of a total of 23. We report for the first time a mutation (c.3471C>G) on exon 21 of the NOTCH3 gene that leads to a cysteine substitution (p.1131C>W) in the EGF-like repeat 29 of the NOTCH3 receptor extracellular domain, and that is responsible for CADASIL in a functionally independent elderly man who came to our attention at the age of 79 because of a minor stroke. CADASIL suspicion aroused only from the finding of severe white matter changes extended to the temporopolar region on cerebral magnetic resonance imaging. This case report underlines that, when CADASIL is suspected, molecular analysis should be performed on all the NOTCH3 exons coding for EGF-like repeats and not be limited to those where mutations have been found with higher frequency, and that the disease may be encountered also in mildly symptomatic elderly patients. The newly reported mutation might sustain a milder expressivity of the disease.

Bone Marrow-Derived Progenitor Cells in Cerebral Autosomal Dominant Arteriopathy With Subcortical Infarcts and Leukoencephalopathy

Background and Purpose— Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is an inherited disease due to cerebral microangiopathy presenting with variable pictures, including stroke, progressive cognitive impairment, and disability. Mechanisms leading from vessel structural changes to parenchymal damage and eventually to clinical expression are not fully understood. Among pathogenic processes, endothelial dysfunction has been hypothesized. Endothelial progenitor cells and circulating progenitor cells (CPCs) derived from bone marrow participate in endothelium structure and function maintenance and contribute to ischemic area revascularization. No data are available about these cells in CADASIL. Our objective in this study was to evaluate endothelial progenitor cells and CPCs role in CADASIL. Methods— Twenty-nine patients with CADASIL and 29 sex- and age-matched control subjects were enrolled. Cells were measured in peripheral blood using flow cytometry. Endothelial progenitor cells were defined as positive for CD34/KDR, CD133/KDR, and CD34/CD133/KDR; and CPCs as positive for CD34, CD133, and CD34/CD133. Results— Endothelial progenitor cells were significantly lower in patients with CADASIL than in control subjects (CD34/KDR: 0.05 versus 0.1 cells/&mgr;L, P=0.005; CD133/KDR: 0.07 versus 0.1 cells/&mgr;L, P=0.006; CD34/CD133/KDR: 0.05 versus 0.1 cells/&mgr;L, P=0.001). The difference remained significant after adjusting for age, sex, and statin use. CPCs were not significantly lower in CADASIL, but patients with stroke or dementia had significantly reduced CPC levels than patients without (CD34: 1.68 versus 2.95 cells/&mgr;L, P=0.007; CD133: 1.40 versus 2.82 cells/&mgr;L, P=0.004; CD34/CD133: 1.44 versus 2.75 cells/&mgr;L, P=0.004). CPC levels significantly correlated with cognitive and motor performance measures. Conclusions— We have documented an association between endothelial progenitor cells and CPCs and CADASIL, extending previous data about the presence of endothelial dysfunction in this disease and its potential role in modulating phenotype.

Genome-Wide Genotyping Demonstrates a Polygenic Risk Score Associated With White Matter Hyperintensity Volume in CADASIL

Background and Purpose— White matter hyperintensities (WMH) on MRI are a quantitative marker for sporadic cerebral small vessel disease and are highly heritable. To date, large-scale genetic studies have identified only a single locus influencing WMH burden. This might in part relate to biological heterogeneity of sporadic WMH. The current study searched for genetic modifiers of WMH volume in cerebral autosomal-dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), a monogenic small vessel disease. Methods— We performed a genome-wide association study to identify quantitative trait loci for WMH volume by combining data from 517 CADASIL patients collected through 7 centers across Europe. WMH volumes were centrally analyzed and quantified on fluid attenuated inversion recovery images. Genotyping was performed using the Affymetrix 6.0 platform. Individuals were assigned to 2 distinct genetic clusters (cluster 1 and cluster 2) based on their genetic background. Results— Four hundred sixty-six patients entered the final genome-wide association study analysis. The phenotypic variance of WMH burden in CADASIL explained by all single nucleotide polymorphisms in cluster 1 was 0.85 (SE=0.21), suggesting a substantial genetic contribution. Using cluster 1 as derivation and cluster 2 as a validation sample, a polygenic score was significantly associated with WMH burden (P=0.001) after correction for age, sex, and vascular risk factors. No single nucleotide polymorphism reached genome-wide significance. Conclusions— We found a polygenic score to be associated with WMH volume in CADASIL subjects. Our findings suggest that multiple variants with small effects influence WMH burden in CADASIL. The identification of these variants and the biological pathways involved will provide insights into the pathophysiology of white matter disease in CADASIL and possibly small vessel disease in general.

White matter microstructural damage in small vessel disease is associated with montreal cognitive assessment but not with mini mental state examination performances: Vascular mild cognitive impairment tuscany study

Background and Purpose— Montreal Cognitive Assessment (MoCA) has been proposed as a screening tool in vascular cognitive impairment. Diffusion tensor imaging is sensitive to white matter microstructural damage. We investigated if diffusion tensor imaging-derived indices are more strongly associated with performances on MoCA or on the widely used mini mental state examination in patients with mild cognitive impairment and small vessel disease. Methods— Mild cognitive impairment patients with moderate/severe degrees of white matter hyperintensities on MRI were enrolled. Lacunar infarcts, cortical atrophy, medial temporal lobe atrophy and median values of mean diffusivity and fractional anisotropy of the cerebral white matter were studied and correlated with cognitive tests performances. Results— Seventy-six patients (mean age 75.1±6.8 years, mean years of education 8.0±4.3) were assessed. In univariate analyses, a significant association of both MoCA and mini mental state examination scores with age, education, cortical atrophy, and medial temporal lobe atrophy was found, whereas mean diffusivity and fractional anisotropy were associated with MoCA. In partial correlation analyses, adjusting for all demographic and neuroimaging variables, both mean diffusivity and fractional anisotropy were associated only with MoCA (mean diffusivity: r= −0.275, P=0.023; fractional anisotropy: r=0.246, P=0.043). Conclusions— In patients with mild cognitive impairment and small vessel disease, diffusion tensor imaging-measured white matter microstructural damage is more related to MoCA than mini mental state examination performances. MoCA is suited for the cognitive screening of patients with small vessel disease.

Risk and Determinants of Dementia in Patients with Mild Cognitive Impairment and Brain Subcortical Vascular Changes: A Study of Clinical, Neuroimaging, and Biological Markers—The VMCI-Tuscany Study: Rationale, Design, and Methodology

Dementia is one of the most disabling conditions. Alzheimers disease and vascular dementia (VaD) are the most frequent causes. Subcortical VaD is consequent to deep-brain small vessel disease (SVD) and is the most frequent form of VaD. Its pathological hallmarks are ischemic white matter changes and lacunar infarcts. Degenerative and vascular changes often coexist, but mechanisms of interaction are incompletely understood. The term mild cognitive impairment defines a transitional state between normal ageing and dementia. Pre-dementia stages of VaD are also acknowledged (vascular mild cognitive impairment, VMCI). Progression relates mostly to the subcortical VaD type, but determinants of such transition are unknown. Variability of phenotypic expression is not fully explained by severity grade of lesions, as depicted by conventional MRI that is not sensitive to microstructural and metabolic alterations. Advanced neuroimaging techniques seem able to achieve this. Beside hypoperfusion, blood-brain-barrier dysfunction has been also demonstrated in subcortical VaD. The aim of the Vascular Mild Cognitive Impairment Tuscany Study is to expand knowledge about determinants of transition from mild cognitive impairment to dementia in patients with cerebral SVD. This paper summarizes the main aims and methodological aspects of this multicenter, ongoing, observational study enrolling patients affected by VMCI with SVD.