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Prevalence of cerebrovascular lesions in patients with Lewy body dementia: A neuropathological study
Clinical Neurology and Neurosurgery 115 (2013) 1094–1097
Contents lists available at SciVerse ScienceDirect
Clinical Neurology and Neurosurgery journal homepage: www.elsevier.com/locate/clineuro
Prevalence of cerebrovascular lesions in patients with Lewy body dementia: A neuropathological study Jacques De Reuck a,∗ , Vincent Deramecourt a,b,c,e , Charlotte Cordonnier a,d , Didier Leys a,d , Florence Pasquier a,c , Claude-Alain Maurage a,b,e a
Université Lille Nord de France, UDSL, EA 1056, F-59000 Lille, France Department of Pathology, Lille University Hospital, F-59000 Lille, France c Memory Clinic, Lille University Hospital, F-59000 Lille, France d Neurovascular Department, Lille University Hospital, F-59000 Lille, France e INSERM U837, F-59000 Lille, France b
a r t i c l e
i n f o
Article history: Received 26 September 2011 Received in revised form 27 October 2012 Accepted 12 November 2012 Available online 10 December 2012 Keywords: Lewy body dementia Mini-bleeds Alzheimer pathology Cerebral amyloid angiopathy Cerebrovascular lesions Vascular risk factors
a b s t r a c t Background: The co-existence of vascular pathology in patients with Lewy body dementia (LBD) is still a matter of debate. This study analyses the prevalence and the severity of cerebrovascular lesions in post-mortem brains of patients with LBD. Patients and methods: Twenty brains of demented patients with autopsy-proven Lewy body disease were compared to 14 brains of age-matched controls. Results: Associated Alzheimer disease (AD) features, stages I–IV, were present in 70% of the LBD brains and in 7% of the controls (P < 0.001). Cerebral amyloid angiopathy (CAA) was only present in 30% and lipohyalinosis in 10%. A semi-quantitative analysis, performed on a coronal section of a whole cerebral hemisphere and on a horizontal section through the pons and the cerebellum, revealed significantly more mini-bleeds in the LBD brains (P = 0.007), predominantly in the cerebral cortex (P = 0.03). Other cerebrovascular lesions were only rarely observed. Comparison of the LDB brains, with and without moderate AD features and CAA, showed no difference in the severity of the cerebrovascular lesions including mini-bleeds. Conclusions: The prevalence of mini-bleeds in LBD brains appears to be independent from the co-existence of moderate AD pathology and CAA. It is more probably due to disturbances of the blood–brain barrier, related to the neurodegenerative process itself. © 2012 Elsevier B.V. All rights reserved.
1. Introduction Alzheimer’s disease (AD) is by far the most common degenerative dementia, followed by vascular dementia (VaD), Lewy body dementia (LBD), and frontotemporal dementia. These dementia subtypes have more overlapping signs and symptoms than defining ones [1,2]. Multiple and different associated pathological features may contribute to a clinical symptom constellation in LBD [3]. Alzheimer-related lesions have an influence on the progression of the neurodegenerative process and on the cognitive decline of LBD patients as well as of Parkinson patients with dementia. On the other hand, the progression of the disease and the cognitive decline are considered as largely independent from co-existent vascular pathology [4,5]. Lewy body pathology is considered inversely correlated to the severity of atherosclerosis, infarcts and small-vessel
∗ Corresponding author. Tel.: +32 9 2218844; fax: +32 9 3324971. E-mail address: [email protected] (J. De Reuck). 0303-8467/$ – see front matter © 2012 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.clineuro.2012.11.005
disease. On the other hand cerebral amyloid angiopathy (CAA), associated to AD features, is frequent in patients with LBD [6,7]. The present post-mortem study compares the prevalence and the severity of cerebrovascular lesions and their responsible factors in a series of brains from patients with LBD to controls. In addition LDB brains with and without coexisting AD features and CAA are mutually compared.
2. Materials and methods 2.1. Dementia and control population From 2000 up to 2010, 158 consecutive patients with a clinical history of a neurodegenerative dementia came to autopsy: in 20 (13%) of them the neuropathological diagnosis of LBD was made. During the same period of time, 14 post-mortem brains of agematched controls were obtained. The controls consisted of brains of elderly patients who died from an illness not related to a brain disease.
J. De Reuck et al. / Clinical Neurology and Neurosurgery 115 (2013) 1094–1097
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2.2. Clinical data and vascular risk factors Thirteen (65%) patients had been followed-up in the Memory Clinic of the Lille University Hospital. Seven (35%) patients were issued from a general hospital. Detailed clinical data, including vascular risk factors were available in 18 patients (90%). The pre-mortem diagnosis of LBD had been retained in 9 of the 20 patients. The presumed clinical diagnosis was AD in 5, Parkinson disease in 4 and Creutzfeldt–Jacob disease in 2 patients. 2.3. Neuropathological analyses The brain tissue samples were first used for diagnosis and afterward integrated in the Lille Neuro-Bank, dependant from the Lille University and co-federated by the “Centre des Resources Biologiques”, acting as institutional review board. The neuropathological evaluation was performed blinded to history and clinical data.
Fig. 1. Old cortico–subcortical mini-bleed composed of perivascular monocytes, macrophages and siderophages, stained by haematoxylin–eosin.
2.3.1. Neurodegenerative lesions Several small samples of the cerebral cortex and of the hippocampus of one fresh cerebral hemisphere were taken for histochemical examination. The remaining brain was fixed in formalin and, after 3 weeks, samples were taken from the primary motor cortex, the associated frontal, temporal and parietal cortex, the primary and secondary visual cortex, the cingulate gyrus, the basal nucleus of Meynert, the amygdaloid body, the hippocampus, basal ganglia, mesencephalon, pons, medulla and cerebellum. Slides from paraffin-embedded sections were immuno-stained for protein tau, -amyloid, ␣-synuclein, prion protein, TDP-43 and ubiquitin. The post-mortem diagnosis of DLB was made according to the Kosaka and McKeith criteria [8]. Additional AD features were staged according to the classification of Braak and Braak [9]. CAA was evaluated, according to the CERAD criteria [10].
of micro-infarcts and of micro- and mini-bleeds, according to the previous described method [11]. The latter were also evaluated according to their location in the cerebral cortex and corticalsubcortical junction, the deep white matter, the striatum, the thalamus, the pons and the cerebellar hemispheres. The white matter changes were restricted to the periventricular regions (R1), scattered in the centrum semiovale (R2) or forming confluent lesions (R3). For the micro-infarcts and micro- and minibleeds R1 corresponded to 1–2, R2 up to 5 and R3 to more than five lesions. Also the regional distribution of the mini-bleeds was determined. The degree of amyloid angiopathy was evaluated on the four cortical slides, stained with anti--amyloid according to the number of affected vessels, as absent (R0), scarce (R1), moderate (R2) and severe (R3).
2.3.2. Cerebrovascular lesions The gross visible cerebrovascular lesions and the small ones, detected on microscopical examination of the small samples, were carefully noted. In addition a semi-quantitative evaluation of small microscopical lesions was performed on a whole coronal section of a cerebral hemisphere, at the level of the mamillary bodies, and a horizontal section through the mid-pons and both cerebellar hemispheres, after staining with haematoxylin–eosin, luxol fast blue (LFB) and Perl. The considered cerebrovascular lesions were bleedings, infarcts, lacunes and white matter changes. Micro-bleeds were defined as small macroscopically visible lesions of 1 mm or 3 mm diameter on gross examination. They consisted of red blood cells, when recent, and of macro- and siderophages, when older. Minibleeds were not visible macroscopically. They were found mainly located around small vessels on microscopical examination (Fig. 1) [11]. Isolated Perl positive deposits were not retained as minibleeds [12]. The term “mini-bleed” was used to avoid confusion with the term “micro-bleed”, used in the MRI literature [13–15]. The degree of white matter changes was mainly evaluated on the LFB stained sections [16]. The degree of CAA was evaluated on slides from the hippocampus, the associated parietal and temporal cortex, and the visual cortex, stained with anti--amyloid. The brains were classified as CAA, when a majority of anti--amyloid stained vessels were present in at least three of the four examined samples and as not-CAA, when absent or scarce, in case of a few stained vessels in one or two slides. This classification was already made at the time of the neuropathological diagnosis and prior to the start of the present quantification study. A semi-quantitative scale, ranking (R) 0–3, was used to evaluate the severity of the white matter changes and the frequency
2.4. Classification of the comparison groups The prevalence and the severity of cerebrovascular lesions were compared in the brains with LBD to the controls. In addition a subgroup analysis was performed comparing the severity of the cerebrovasular lesions in the LDB brains with (n = 14) and without AD features and CAA (n = 6). 2.5. Statistical analyses The statistical analysis compared the items of the LBD group with the control group and of the LBD subgroups, with and without moderate AD features and CAA. Univariate comparisons of unpaired groups were done with the Fisher’s exact test for categorical data. The non-parametric Mann–Whitney U-test was used to compare continuous variables. The significance level was set at 0.05, twotailed. 3. Results The median age of patients with LBD was 78 (inter quartile range [IQR] 75–87) years versus 74 (IQR 73–86) years in the controls (P = 1.0). Male gender was 70% in the former and 37% in the latter group (P = 0.05). Vascular risk factors (arterial hypertension, diabetes, hypercholestolemia and smoking) and the use of antithrombotic treatment were similar in both groups (Table 1). Moderate AD features (stages I–IV) were found in 70% of the brains with LBD and in 7% of the control brains (P < 0.001). CAA was observed in 30% of the LBD versus 7% in the controls brains
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J. De Reuck et al. / Clinical Neurology and Neurosurgery 115 (2013) 1094–1097
Table 1 Comparison of the number (percentage) of patients with vascular risk factors and antithrombotic medication among the group with Lewy body dementia (LBD) and among controls.
Table 4 Comparison of mean ranking scores (standard deviations) of the severity of the cerebrovascular lesions in post-mortem brains among patients with Lewy body dementia with (LDB-AD) and without Alzheimer features (LDB).
Items
LBD (n = 18)
Controls (n = 12)
P value
Items
LBD-AD (n = 14)
LBD (n = 6)
P value
Arterial hypertension Diabetes Hypercholesterolemia Smoking Antithrombotic treatment
7 (41) 0 (0) 2 (18) 1 (6) 7 (41)
2 (17) 1 (8) 3 (25) 0 (0) 3 (25)
0.25 0.40 0.62 1.0 0.69
White matter changes Amyloid angiopathy Cortical micro-infarcts Micro-bleeds Mini-bleeds: total Cortico–subcortical Centrum semiovale Striatum Thalamus Brainstem Cerebellum
0.9 (1.1) 0.9 (1.2) 0.4 (1.1) 0.0 (0.0) 1.3 (1.1) 0.6 (0.9) 0.6 (0.9) 0.4 (0.6) 0.2 (0.4) 0.4 (0.8) 1.1 (1.3)
0.7 (0.4) 0.0 (0.0) 0.2 (0.4) 0.0 (0.0) 1.8 (1.0) 1.3 (1.2) 0.5 (0.6) 0.3 (0.8) 0.2 (0.4) 0.5 (1.2) 0.5 (0.8)
0.90 0.09 0.97 1.0 0.31 0.24 0.84 0.78 0.90 0.97 0.44
Table 2 Comparison of the number (percentage) of brains with cerebrovascular lesions among patients with Lewy body dementia (LBD) and among controls. Items
LBD (n = 20)
Controls (n = 14)
P value
White matter changes Lacunar infarcts Cortical territorial infarcts Cortical micro-infarcts Haematomas Micro-bleeds Mini-bleeds
9 (45) 1 (5) 4 (20) 3 (15) 1 (5) 0 (0) 16 (80)
3 (21) 0 (0) 0 (0) 3 (21) 0 (0) 0 (0) 6 (43)
0.27 1.0 0.13 0.67 1.0 1.0 0.04
(P = 0.16). Lipohyalinosis was found in 10% of LBD group versus 0% in controls (P = 0.50). There was a significant prevalence of brains with mini-bleeds (P = 0.04) in the LBD group compared to the control, without differences for the other cerebrovascular lesions (Table 2). Quantification of the histological lesions showed a higher mean overall ranking score for mini-bleeds in the LBD brains (P < 0.01), with a significant predominance in the cortico–subcortical regions (P = 0.03) compared to the control brains. The mean ranking score for CAA was not statistically different between in LBD and the control brains (P = 0.16). Also the quantification of other cerebrovascular lesions did not show statistically significant differences (Table 3). The median age of the LBD patients with AD features and CAA was 77 (IQR 74–87) years and of those without 79 (IQR 78–80) years (P = 0.90). Male gender was 57% in the former and 100% in the latter group (P = 0.12). Quantification of the histological lesions showed no differences between both groups, in particular concerning the severity of mini-bleeds (Table 4). 4. Discussion Our neuropathological study shows that only mini-bleeds are more frequent in LBD brains compared to controls. They predominate in the cortico–subcortical regions. No other cerebrovascular lesions prevail. The co-existence of moderate AD and CAA pathologies did not influence this prevalence in LBD brains. Both the LBD as Table 3 Comparison of mean ranking scores (standard deviations) of the severity of the cerebrovascular lesions in post-mortem brains among patients with Lewy body dementia (LBD) and among controls. Items
LBD (n = 20)
Controls (n = 14)
P value
White matter changes Amyloid angiopathy Cortical micro-infarcts Micro-bleeds Mini-bleeds: total Cortico–subcortical Deep white matter Striatum Thalamus Brainstem Cerebellum
0.8 (1.1) 0.7 (1.1) 0.3 (1.0) 0.0 (0.0) 1.5 (1.1) 0.9 (1.0) 0.6 (0.8) 0.4 (0.7) 0.2 (0.4) 0.4 (1.0) 0.9 (1.2)
0.2 (0.4) 0.1 (0.3) 0.2 (0.4) 0.0 (0.0) 0.4 (0.5) 0.1 (0.3) 0.2 (0.4) 0.0 (0.0) 0.0 (0.0) 0.0 (0.0) 0.2 (0.4)
0.15 0.16 0.80 1.0 <0.01 0.03 0.27 0.23 0.34 0.34 0.15
the control patients are age-matched and have a similar incidence of vascular risk factors and use of antithrombotic medication. An inverse relationship between the occurrence of cerebrovascular lesions and the severity of Lewy body pathology has already been demonstrated [17]. Prevalence of cerebrovascular lesions has only been observed in LBD brains with severe AD features [18]. It was shown that CAA occurs in older patients with LBD and is associated with the presence of AD features [6]. In a large neuropathological study CAA was not found to be the most significant risk factor for intracerebral haemorrhages. However, small cerebral bleeds were not taken into account in this study [19]. The present study confirms the concomitant occurrence of CAA and AD features in LBD brains. They do not represent an increased risk for additional cerebrovascular lesions, probably due to their lack of severity. They are not responsible for the prevalence of cortico–subcortical minibleeds as their predominance is equal in the LBD brains with and without CAA and AD features. An increased prevalence and severity of mini-bleeds, with a predilection for the cerebral cortex and the cortico–subcortical junction, are also observed in AD brains [18]. The mini-bleeds occur preferentially in the regions with the most prominent neurodegenerative changes [20]. Their occurrence is more severe and widespread in case of associated CAA [21]. Although there is no global increase of mini-bleeds in frontotemporal lobar degeneration [22], on 7.0 T magnetic resonance imaging a predominance of mini-bleeds is demonstrated in the affected frontal cortex of post-mortem brains [23]. The similarity of the predominance of mini-bleeds in the cerebral cortex in AD and in frontotemporal lobar degeneration with those in LBD suggests a similar origin. They are not related to associated cerebrovascular disease but probably are due to brain–barrier destruction, related to the neurodegenerative process itself. This cortico–subcortical predominance of mini-bleeds occurs in these different neurodegenerative dementias and can perhaps been explained by the particular cortico–subcortical angioarchitecture, compared to other brain regions [24]. In conclusion, cerebrovascular lesions are rare in brains of LDB patients except for mini-bleeds, that have to be related to the LBD itself and not to associated AD and CAA features. References [1] Focht A. Differential diagnosis of dementia. Geriatrics 2009;64:20–6. [2] De Reuck J. The significance of small cerebral bleeds in neurodegenerative dementia syndromes. Aging and Disease 2012;3:307–12. [3] Londos E, Passant U, Risberg J, Gustafson L, Brun A. Contributions of other brain pathologies in dementia with Lewy bodies. Dementia and Geriatric Cognitive Disorders 2002;13:130–48. [4] Haugarvoll K, Aarsland D, Wentzel-Larsen T, Larsen JP. The influence of cerebrovascular risk factors on incident dementia in patients with Parkinson’s disease. Acta Neurologica Scandinavica 2005;112:386–90.
J. De Reuck et al. / Clinical Neurology and Neurosurgery 115 (2013) 1094–1097 [5] Jellinger KA, Attems J. Prevalence of impact of vascular and Alzheimer pathologies in Lewy body disease. Acta Neuropathologica 2008;115:427–36. [6] Deramcourt V, Bombois S, Maurage CA, et al. Biochemical staging of synucleinopathy and amyloid deposition in dementia with Lewy bodies. Journal of Neuropathology and Experimental Neurology 2006;65:278–88. [7] Jellinger KA, Attems J. Cerebral amyloid angiopathy in Lewy body disease. Journal of Neural Transmission 2008;115:473–82. [8] McKeith IG, Dickson DW, Lowe J, et al. Diagnosis and management of dementia with Lewy bodies: third report of the DLB consortium. Neurology 2005;65:1863–72. [9] Braak H, Braak E. Evolution of neuronal changes in the course of Alzheimer’s disease. Journal of Neural Transmission 1998;53(Suppl):127–40. [10] Ellis RJ, Olichney JM, Thal LJ, et al. Cerebral amyloid angiopathy in brains of patients with Alzheimer’s disease: the CERAD experience, part XV. Neurology 1996;46:1592–6. [11] De Reuck J, Deramecourt V, Cordonnier C, Leys D, Pasquier F, Maurage CA. Prevalence of small cerebral bleeds in patients with a neurodegenerative dementia: a neuropathological study. Journal of the Neurological Sciences 2011;300:63–6. [12] De Reuck J. Histopathological stainings and definitions of vascular disruption in the elderly brain. Experimental Gerontology 2012;47:834–7. [13] Greenberg SM, Vernooij MW, Cordonnier C, et al. Microbleed Study Group: cerebral microbleeds: a guide to detection and interpretation. Lancet Neurology 2009;8:165–74. [14] Cordonnier C, Al-Shahi Salman R, Wardlaw J. Spontaneous brain microbleeds: systematic review, subgroup analyses and standards for study design and reporting. Brain 2007;130:1988–2003. [15] Cordonnier C, van der Flier WM, Sluimer JD, Leys D, Barkhof F, Scheltens Ph. Prevalence and severity of microbleeds in a memory clinic setting. Neurology 2008;66:1356–60.
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[16] Englund E, Brun A. White matter changes in dementia of Alzheimer’s type: the difference in vulnerability between cell compartments. Histopathology 1990;16:433–9. [17] Ghebremedhin E, Rosenberger A, Rub U, et al. Inverse relationship between cerebrovascular lesions and severity of Lewy body pathology in patients with Lewy body diseases. Journal of Neuropathology and Experimental Neurology 2010;69:442–8. [18] Jellinger KA. Prevalence and impact of cerebrovascular lesions in Alzheimer and Lewy body diseases. Neurodegenerative Diseases 2010;7:112–6. [19] Jellinger KA, Lauda F, Attems J. Sporadic cerebral amyloid angiopathy is not a frequent cause of spontaneous hemorrhage. European Journal of Neurology 2007;14:923–8. [20] De Reuck J, Cordonnier C, Deramecourt V, et al. Microbleeds in postmortem brains of patients with Alzheimer disease. A T2*-weighted gradient-echo 7.0 T magnetic resonance imaging study. Alzheimer Disease & Associated Disorders 2012 [Epub ahead of print]. [21] De Reuck J, Deramecourt V, Cordonnier C, Leys D, Maurage CA, Pasquier F. The impact of cerebral amyloid angiopathy on the occurrence of cerebrovascular lesions in demented patients with Alzheimer features: a neuropathological study. European Journal of Neurology 2011;18:313–8. [22] De Reuck J, Deramecourt, Cordonnier C, Leys D, Pasquier F, Maurage CA. cerebrovascular lesions in patients with frontotemporal lobar degeneration: a neuropathological study. Neurodegenerative Diseases 2012;9:170–5. [23] De Reuck J, Deramecourt V, Cordonnier C, et al. Detection of microbleeds in post-mortem brains of patients with frontotemporal lobar degeneration: a 7.0-Tesla magnetic resonance imaging with neuropathological correlates. European Journal of Neurology 2012;19:1355–60. [24] De Reuck J. The cortico–subcortical arterial angioarchitecture in human brain. Acta Neurologica Belgica 1972;72:323–9.
Contents lists available at SciVerse ScienceDirect
Clinical Neurology and Neurosurgery journal homepage: www.elsevier.com/locate/clineuro
Prevalence of cerebrovascular lesions in patients with Lewy body dementia: A neuropathological study Jacques De Reuck a,∗ , Vincent Deramecourt a,b,c,e , Charlotte Cordonnier a,d , Didier Leys a,d , Florence Pasquier a,c , Claude-Alain Maurage a,b,e a
Université Lille Nord de France, UDSL, EA 1056, F-59000 Lille, France Department of Pathology, Lille University Hospital, F-59000 Lille, France c Memory Clinic, Lille University Hospital, F-59000 Lille, France d Neurovascular Department, Lille University Hospital, F-59000 Lille, France e INSERM U837, F-59000 Lille, France b
a r t i c l e
i n f o
Article history: Received 26 September 2011 Received in revised form 27 October 2012 Accepted 12 November 2012 Available online 10 December 2012 Keywords: Lewy body dementia Mini-bleeds Alzheimer pathology Cerebral amyloid angiopathy Cerebrovascular lesions Vascular risk factors
a b s t r a c t Background: The co-existence of vascular pathology in patients with Lewy body dementia (LBD) is still a matter of debate. This study analyses the prevalence and the severity of cerebrovascular lesions in post-mortem brains of patients with LBD. Patients and methods: Twenty brains of demented patients with autopsy-proven Lewy body disease were compared to 14 brains of age-matched controls. Results: Associated Alzheimer disease (AD) features, stages I–IV, were present in 70% of the LBD brains and in 7% of the controls (P < 0.001). Cerebral amyloid angiopathy (CAA) was only present in 30% and lipohyalinosis in 10%. A semi-quantitative analysis, performed on a coronal section of a whole cerebral hemisphere and on a horizontal section through the pons and the cerebellum, revealed significantly more mini-bleeds in the LBD brains (P = 0.007), predominantly in the cerebral cortex (P = 0.03). Other cerebrovascular lesions were only rarely observed. Comparison of the LDB brains, with and without moderate AD features and CAA, showed no difference in the severity of the cerebrovascular lesions including mini-bleeds. Conclusions: The prevalence of mini-bleeds in LBD brains appears to be independent from the co-existence of moderate AD pathology and CAA. It is more probably due to disturbances of the blood–brain barrier, related to the neurodegenerative process itself. © 2012 Elsevier B.V. All rights reserved.
1. Introduction Alzheimer’s disease (AD) is by far the most common degenerative dementia, followed by vascular dementia (VaD), Lewy body dementia (LBD), and frontotemporal dementia. These dementia subtypes have more overlapping signs and symptoms than defining ones [1,2]. Multiple and different associated pathological features may contribute to a clinical symptom constellation in LBD [3]. Alzheimer-related lesions have an influence on the progression of the neurodegenerative process and on the cognitive decline of LBD patients as well as of Parkinson patients with dementia. On the other hand, the progression of the disease and the cognitive decline are considered as largely independent from co-existent vascular pathology [4,5]. Lewy body pathology is considered inversely correlated to the severity of atherosclerosis, infarcts and small-vessel
∗ Corresponding author. Tel.: +32 9 2218844; fax: +32 9 3324971. E-mail address: [email protected] (J. De Reuck). 0303-8467/$ – see front matter © 2012 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.clineuro.2012.11.005
disease. On the other hand cerebral amyloid angiopathy (CAA), associated to AD features, is frequent in patients with LBD [6,7]. The present post-mortem study compares the prevalence and the severity of cerebrovascular lesions and their responsible factors in a series of brains from patients with LBD to controls. In addition LDB brains with and without coexisting AD features and CAA are mutually compared.
2. Materials and methods 2.1. Dementia and control population From 2000 up to 2010, 158 consecutive patients with a clinical history of a neurodegenerative dementia came to autopsy: in 20 (13%) of them the neuropathological diagnosis of LBD was made. During the same period of time, 14 post-mortem brains of agematched controls were obtained. The controls consisted of brains of elderly patients who died from an illness not related to a brain disease.
J. De Reuck et al. / Clinical Neurology and Neurosurgery 115 (2013) 1094–1097
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2.2. Clinical data and vascular risk factors Thirteen (65%) patients had been followed-up in the Memory Clinic of the Lille University Hospital. Seven (35%) patients were issued from a general hospital. Detailed clinical data, including vascular risk factors were available in 18 patients (90%). The pre-mortem diagnosis of LBD had been retained in 9 of the 20 patients. The presumed clinical diagnosis was AD in 5, Parkinson disease in 4 and Creutzfeldt–Jacob disease in 2 patients. 2.3. Neuropathological analyses The brain tissue samples were first used for diagnosis and afterward integrated in the Lille Neuro-Bank, dependant from the Lille University and co-federated by the “Centre des Resources Biologiques”, acting as institutional review board. The neuropathological evaluation was performed blinded to history and clinical data.
Fig. 1. Old cortico–subcortical mini-bleed composed of perivascular monocytes, macrophages and siderophages, stained by haematoxylin–eosin.
2.3.1. Neurodegenerative lesions Several small samples of the cerebral cortex and of the hippocampus of one fresh cerebral hemisphere were taken for histochemical examination. The remaining brain was fixed in formalin and, after 3 weeks, samples were taken from the primary motor cortex, the associated frontal, temporal and parietal cortex, the primary and secondary visual cortex, the cingulate gyrus, the basal nucleus of Meynert, the amygdaloid body, the hippocampus, basal ganglia, mesencephalon, pons, medulla and cerebellum. Slides from paraffin-embedded sections were immuno-stained for protein tau, -amyloid, ␣-synuclein, prion protein, TDP-43 and ubiquitin. The post-mortem diagnosis of DLB was made according to the Kosaka and McKeith criteria [8]. Additional AD features were staged according to the classification of Braak and Braak [9]. CAA was evaluated, according to the CERAD criteria [10].
of micro-infarcts and of micro- and mini-bleeds, according to the previous described method [11]. The latter were also evaluated according to their location in the cerebral cortex and corticalsubcortical junction, the deep white matter, the striatum, the thalamus, the pons and the cerebellar hemispheres. The white matter changes were restricted to the periventricular regions (R1), scattered in the centrum semiovale (R2) or forming confluent lesions (R3). For the micro-infarcts and micro- and minibleeds R1 corresponded to 1–2, R2 up to 5 and R3 to more than five lesions. Also the regional distribution of the mini-bleeds was determined. The degree of amyloid angiopathy was evaluated on the four cortical slides, stained with anti--amyloid according to the number of affected vessels, as absent (R0), scarce (R1), moderate (R2) and severe (R3).
2.3.2. Cerebrovascular lesions The gross visible cerebrovascular lesions and the small ones, detected on microscopical examination of the small samples, were carefully noted. In addition a semi-quantitative evaluation of small microscopical lesions was performed on a whole coronal section of a cerebral hemisphere, at the level of the mamillary bodies, and a horizontal section through the mid-pons and both cerebellar hemispheres, after staining with haematoxylin–eosin, luxol fast blue (LFB) and Perl. The considered cerebrovascular lesions were bleedings, infarcts, lacunes and white matter changes. Micro-bleeds were defined as small macroscopically visible lesions of 1 mm or 3 mm diameter on gross examination. They consisted of red blood cells, when recent, and of macro- and siderophages, when older. Minibleeds were not visible macroscopically. They were found mainly located around small vessels on microscopical examination (Fig. 1) [11]. Isolated Perl positive deposits were not retained as minibleeds [12]. The term “mini-bleed” was used to avoid confusion with the term “micro-bleed”, used in the MRI literature [13–15]. The degree of white matter changes was mainly evaluated on the LFB stained sections [16]. The degree of CAA was evaluated on slides from the hippocampus, the associated parietal and temporal cortex, and the visual cortex, stained with anti--amyloid. The brains were classified as CAA, when a majority of anti--amyloid stained vessels were present in at least three of the four examined samples and as not-CAA, when absent or scarce, in case of a few stained vessels in one or two slides. This classification was already made at the time of the neuropathological diagnosis and prior to the start of the present quantification study. A semi-quantitative scale, ranking (R) 0–3, was used to evaluate the severity of the white matter changes and the frequency
2.4. Classification of the comparison groups The prevalence and the severity of cerebrovascular lesions were compared in the brains with LBD to the controls. In addition a subgroup analysis was performed comparing the severity of the cerebrovasular lesions in the LDB brains with (n = 14) and without AD features and CAA (n = 6). 2.5. Statistical analyses The statistical analysis compared the items of the LBD group with the control group and of the LBD subgroups, with and without moderate AD features and CAA. Univariate comparisons of unpaired groups were done with the Fisher’s exact test for categorical data. The non-parametric Mann–Whitney U-test was used to compare continuous variables. The significance level was set at 0.05, twotailed. 3. Results The median age of patients with LBD was 78 (inter quartile range [IQR] 75–87) years versus 74 (IQR 73–86) years in the controls (P = 1.0). Male gender was 70% in the former and 37% in the latter group (P = 0.05). Vascular risk factors (arterial hypertension, diabetes, hypercholestolemia and smoking) and the use of antithrombotic treatment were similar in both groups (Table 1). Moderate AD features (stages I–IV) were found in 70% of the brains with LBD and in 7% of the control brains (P < 0.001). CAA was observed in 30% of the LBD versus 7% in the controls brains
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Table 1 Comparison of the number (percentage) of patients with vascular risk factors and antithrombotic medication among the group with Lewy body dementia (LBD) and among controls.
Table 4 Comparison of mean ranking scores (standard deviations) of the severity of the cerebrovascular lesions in post-mortem brains among patients with Lewy body dementia with (LDB-AD) and without Alzheimer features (LDB).
Items
LBD (n = 18)
Controls (n = 12)
P value
Items
LBD-AD (n = 14)
LBD (n = 6)
P value
Arterial hypertension Diabetes Hypercholesterolemia Smoking Antithrombotic treatment
7 (41) 0 (0) 2 (18) 1 (6) 7 (41)
2 (17) 1 (8) 3 (25) 0 (0) 3 (25)
0.25 0.40 0.62 1.0 0.69
White matter changes Amyloid angiopathy Cortical micro-infarcts Micro-bleeds Mini-bleeds: total Cortico–subcortical Centrum semiovale Striatum Thalamus Brainstem Cerebellum
0.9 (1.1) 0.9 (1.2) 0.4 (1.1) 0.0 (0.0) 1.3 (1.1) 0.6 (0.9) 0.6 (0.9) 0.4 (0.6) 0.2 (0.4) 0.4 (0.8) 1.1 (1.3)
0.7 (0.4) 0.0 (0.0) 0.2 (0.4) 0.0 (0.0) 1.8 (1.0) 1.3 (1.2) 0.5 (0.6) 0.3 (0.8) 0.2 (0.4) 0.5 (1.2) 0.5 (0.8)
0.90 0.09 0.97 1.0 0.31 0.24 0.84 0.78 0.90 0.97 0.44
Table 2 Comparison of the number (percentage) of brains with cerebrovascular lesions among patients with Lewy body dementia (LBD) and among controls. Items
LBD (n = 20)
Controls (n = 14)
P value
White matter changes Lacunar infarcts Cortical territorial infarcts Cortical micro-infarcts Haematomas Micro-bleeds Mini-bleeds
9 (45) 1 (5) 4 (20) 3 (15) 1 (5) 0 (0) 16 (80)
3 (21) 0 (0) 0 (0) 3 (21) 0 (0) 0 (0) 6 (43)
0.27 1.0 0.13 0.67 1.0 1.0 0.04
(P = 0.16). Lipohyalinosis was found in 10% of LBD group versus 0% in controls (P = 0.50). There was a significant prevalence of brains with mini-bleeds (P = 0.04) in the LBD group compared to the control, without differences for the other cerebrovascular lesions (Table 2). Quantification of the histological lesions showed a higher mean overall ranking score for mini-bleeds in the LBD brains (P < 0.01), with a significant predominance in the cortico–subcortical regions (P = 0.03) compared to the control brains. The mean ranking score for CAA was not statistically different between in LBD and the control brains (P = 0.16). Also the quantification of other cerebrovascular lesions did not show statistically significant differences (Table 3). The median age of the LBD patients with AD features and CAA was 77 (IQR 74–87) years and of those without 79 (IQR 78–80) years (P = 0.90). Male gender was 57% in the former and 100% in the latter group (P = 0.12). Quantification of the histological lesions showed no differences between both groups, in particular concerning the severity of mini-bleeds (Table 4). 4. Discussion Our neuropathological study shows that only mini-bleeds are more frequent in LBD brains compared to controls. They predominate in the cortico–subcortical regions. No other cerebrovascular lesions prevail. The co-existence of moderate AD and CAA pathologies did not influence this prevalence in LBD brains. Both the LBD as Table 3 Comparison of mean ranking scores (standard deviations) of the severity of the cerebrovascular lesions in post-mortem brains among patients with Lewy body dementia (LBD) and among controls. Items
LBD (n = 20)
Controls (n = 14)
P value
White matter changes Amyloid angiopathy Cortical micro-infarcts Micro-bleeds Mini-bleeds: total Cortico–subcortical Deep white matter Striatum Thalamus Brainstem Cerebellum
0.8 (1.1) 0.7 (1.1) 0.3 (1.0) 0.0 (0.0) 1.5 (1.1) 0.9 (1.0) 0.6 (0.8) 0.4 (0.7) 0.2 (0.4) 0.4 (1.0) 0.9 (1.2)
0.2 (0.4) 0.1 (0.3) 0.2 (0.4) 0.0 (0.0) 0.4 (0.5) 0.1 (0.3) 0.2 (0.4) 0.0 (0.0) 0.0 (0.0) 0.0 (0.0) 0.2 (0.4)
0.15 0.16 0.80 1.0 <0.01 0.03 0.27 0.23 0.34 0.34 0.15
the control patients are age-matched and have a similar incidence of vascular risk factors and use of antithrombotic medication. An inverse relationship between the occurrence of cerebrovascular lesions and the severity of Lewy body pathology has already been demonstrated [17]. Prevalence of cerebrovascular lesions has only been observed in LBD brains with severe AD features [18]. It was shown that CAA occurs in older patients with LBD and is associated with the presence of AD features [6]. In a large neuropathological study CAA was not found to be the most significant risk factor for intracerebral haemorrhages. However, small cerebral bleeds were not taken into account in this study [19]. The present study confirms the concomitant occurrence of CAA and AD features in LBD brains. They do not represent an increased risk for additional cerebrovascular lesions, probably due to their lack of severity. They are not responsible for the prevalence of cortico–subcortical minibleeds as their predominance is equal in the LBD brains with and without CAA and AD features. An increased prevalence and severity of mini-bleeds, with a predilection for the cerebral cortex and the cortico–subcortical junction, are also observed in AD brains [18]. The mini-bleeds occur preferentially in the regions with the most prominent neurodegenerative changes [20]. Their occurrence is more severe and widespread in case of associated CAA [21]. Although there is no global increase of mini-bleeds in frontotemporal lobar degeneration [22], on 7.0 T magnetic resonance imaging a predominance of mini-bleeds is demonstrated in the affected frontal cortex of post-mortem brains [23]. The similarity of the predominance of mini-bleeds in the cerebral cortex in AD and in frontotemporal lobar degeneration with those in LBD suggests a similar origin. They are not related to associated cerebrovascular disease but probably are due to brain–barrier destruction, related to the neurodegenerative process itself. This cortico–subcortical predominance of mini-bleeds occurs in these different neurodegenerative dementias and can perhaps been explained by the particular cortico–subcortical angioarchitecture, compared to other brain regions [24]. In conclusion, cerebrovascular lesions are rare in brains of LDB patients except for mini-bleeds, that have to be related to the LBD itself and not to associated AD and CAA features. References [1] Focht A. Differential diagnosis of dementia. Geriatrics 2009;64:20–6. [2] De Reuck J. The significance of small cerebral bleeds in neurodegenerative dementia syndromes. Aging and Disease 2012;3:307–12. [3] Londos E, Passant U, Risberg J, Gustafson L, Brun A. Contributions of other brain pathologies in dementia with Lewy bodies. Dementia and Geriatric Cognitive Disorders 2002;13:130–48. [4] Haugarvoll K, Aarsland D, Wentzel-Larsen T, Larsen JP. The influence of cerebrovascular risk factors on incident dementia in patients with Parkinson’s disease. Acta Neurologica Scandinavica 2005;112:386–90.
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