Cerebral amyloid angiopathy,white matter lesions and Alzheimer encephalopathy - a histopathological assessment

To test the hypothesis that the cerebral amyloid angiopathy (CAA) of Alzheimer's disease (AD) is quantitatively associated with white matter lesions (WML), the brains of 63 demented patients exhibiting varying degrees of Alzheimer encephalopathy (AE) were examined, along with those of 10 nondemented control cases. The ratio of amyloid-positive to amyloid-negative vessels in the leptomeninges of the frontal pole from each patient was calculated subsequent to microscopical examination, and the severity of WML was graded according to previously published criteria. In AD cases without a significant component of vascular dementia, the level of CAA was found to correlate with the degree of WML diagnosed and graded by neuropathology. Neither age nor severity of AE correlated significantly with WML. There may be several reasons for the conflicting results of this study vis-à-vis earlier investigations; the roles played by different methods of staining, CAA quantitation and patient subgroup selection are also discussed.     

Alzheimer病和伴有痴呆Parkinson病的临床病理研究

研究Ａｌｚｈｅｉｍｅｒ病（ＡＤ）和伴有痴呆Ｐａｒｋｉｎｓｏｎ病（ＰＤ）以及年龄配对的对照组尸检病例各３例，主要观察额叶和颁叶皮质、黑质、蓝斑、Ｍｅｙｎｅｒｔ核的神经元数量和Ｌｅｗｙ小体的形成。从统计结果看，ＡＤ和ＰＤ与对照组比较，各部位的神经元数量均明显减少（Ｐ＜０．０１）。常见于ＰＤ的Ｌｅｗｙ小体，在两例ＡＤ患者的黑质和蓝斑色素神经元中也可见到，但其并非ＡＤ特有的病理改变。临床上诊断为特发性ＰＤ的３例和有强直表现的１例ＡＤ患者的黑质色素神经元减少均在５０％以上；而无锥体外系受累症状的两例ＡＤ患者，虽也有减少，但均未达到５０％。     

Ubiquitin in cerebral amyloid angiopathy.

Immunohistological findings in cerebral blood vessels of 4 cases with cerebral amyloid angiopathy (CAA) were compared with those of 4 Alzheimer's (AD) cases. A panel of antibodies against 2 neurofilament subunits (BF10 and RT97), a microtubule-associated protein (TAU) and ubiquitin were used. CAA cases showed a strong immunoreactivity for ubiquitin in blood vessel wall. Senile plaques (SPs) in CAA cases showed strong ubiquitin positivity but the central amyloid core was negative. AD brains showed immunoreactivity with all antibodies in SPs and neurofibrillary tangles (NFTs); blood vessels were consistently negative for ubiquitin. Control brains showed few SPs and NFTs; these were positive for ubiquitin, but blood vessels were negative. These results indicate that vascular amyloid deposition in CAA and AD may have different pathophysiological mechanisms.     

Stroke related to cerebral amyloid angiopathy: the significance of systemic vascular disease

Summary A retrospective postmortem analysis of 25 cases of cerebral amyloid angiopathy (CAA) in the setting of Alzheimer's disease or senile dementia of the Alzheimer type (AD/SDAT) is reported. Seven patients experienced clinically significant cerebral infarcts or hemorrhages or both. There was no statistically significant difference in the incidence of infarcts or hemorrhages in hypertensive and nonhypertensive patients. Hypertension does not appear to be an additional risk factor in the causation of cerebral infarct or hemorrhage associated with CAA in the setting of AD/SDAT. Just over half of patients with CAA and significant ischemic and/or hemorrhagic brain lesions showed atherosclerosis of the circle of Willis, sometimes in the context of severe disseminated atheromatous disease.     

The Lewy body variant of Alzheimer's disease: a clinical and pathologic entity

Thirty-six clinically diagnosed and pathologically confirmed Alzheimer's disease (AD) patients included 13 with cortical and subcortical Lewy bodies (LBs). The patients with LBs appeared to constitute a distinct neuropathologic and clinical subset of AD, the Lewy body variant (LBV). The LBV group showed gross pallor of the substantia nigra, greater neuron loss in the locus ceruleus, substantia nigra, and substantia innominata, lower neocortical ChAT levels, and fewer midfrontal tangles than did the pure AD group, along with a high incidence of medial temporal lobe spongiform vacuolization. Analysis of neuropsychological tests from 9 LBV subjects and 9 AD patients matched for age and degree of dementia revealed greater deficits in attention, fluency, and visuospatial processing in the LBV group. Similar comparisons of neurologic examinations showed a significant increase in masked facies; in addition there was an increase in essential tremor, bradykinesia, mild neck rigidity, and slowing of rapid alternating movements in the LBV group. Extremity rigidity, flexed posture, resting tremor, or other classic parkinsonian features were not characteristic of the LBV patient. In some cases, it may be possible to diagnose LBV premortem on the basis of the clinical and neuropsychological features.     

Lewy body and Alzheimer pathology in a family with the amyloid-β precursor protein APP717 gene mutation

Mutations in the amyloid precursor protein (APP) gene cause one form of early onset familial Alzheimer’s disease (AD). One such family has been studied genetically and neuropathologically and represents the basis of the present report. Four siblings with the APP717 Val to Ile mutation, aged 59, 65, 61 and 64 years, apolipoprotein E (APOE) genotyped 2,4 (first three) and 2,3 respectively, had severe AD, Braak stage VI with frequent neurofibrillary tangles in the primary visual cortex, Brodmann area 17. The first one also met McKeith criteria for the limbic stage of dementia with Lewy bodies but did not have substantia nigra Lewy bodies. The second two met McKeith criteria for the neocortical stage of dementia with Lewy bodies and both had substantia nigra Lewy bodies. The fourth had AD but no Lewy bodies. A cousin without the APP717 mutation who was APOE 3, 4, developed dementia at age 60 and died at age 75. She had severe cerebrovascular atherosclerosis, less severe AD, Braak stage V, with sparing of area 17. She also had Lewy bodies in the substantia nigra and in the cortex and met McKeith criteria for neocortical stage of dementia with Lewy bodies. Extrapyramidal features were present in all five. Lewy bodies have been described in 53% of reported autopsies on individuals with the APP717 Val to Ile mutation coincident with dementia and AD neuropathologic changes. These observations suggest an association between the chromosome 21 APP mutation and Lewy body formation, possibly mediated by other environmental or genetic factors. Received: 6 July 1999 / Revised, accepted: 19 October 1999     

The Consortium to Establish a Registry for Alzheimer's Disease (CERAD). Part II. Standardization of the neuropathologic assessment of Alzheimer's disease

The Neuropathology Task Force of the Consortium to Establish a Registry for Alzheimer's Disease (CERAD) has developed a practical and standardized neuropathology protocol for the postmortem assessment of dementia and control subjects. The protocol provides neuropathologic definitions of such terms as "definite Alzheimer's disease" (AD), "probable AD," "possible AD," and "normal brain" to indicate levels of diagnostic certainty, reduce subjective interpretation, and assure common language. To pretest the protocol, neuropathologists from 15 participating centers entered information on autopsy brains from 142 demented patients clinically diagnosed as probable AD and on eight nondemented patients. Eighty-four percent of the dementia cases fulfilled CERAD neuropathologic criteria for definite AD. As increasingly large numbers of prospectively studied dementia and control subjects are autopsied, the CERAD neuropathology protocol will help to refine diagnostic criteria, assess overlapping pathology, and lead to a better understanding of early subclinical changes of AD and normal aging.     

Neuropathological correlates to clinically defined dementia with Lewy bodies

OBJECTIVES: To analyse the neuropathological changes behind clinically defined dementia with Lewy bodies (clinDLB) compared with clinically diagnosed Alzheimer's disease (clinAD). METHODS: The prevalence of neuropathological findings in 48 clinDLB and 45 clinAD cases was compared. Sixteen clinDLB and 10 clinAD cases were reassessed with alpha-synuclein staining for Lewy bodies (LB). RESULTS: Alzheimer pathology was found in 81% of the clinDLB and 93% of the clinAD cases. The clinDLB group had a higher prevalence of frontal white matter pathology, mostly of ischemic type, and a more severe degeneration of the substantia nigra compared with the clinAD group. In hematoxylin-eosin staining, LBs were identified in seven (15%) of the clinDLB and in four (9%) of the clinAD group. In alpha-synuclein staining, 38% of the clinDLB and 40% of the clinAD cases exhibited LBs. The cases without LBs, in the clinDLB group, had AD pathology in combination with frontal white matter disease. Vascular pathology of significant degree was prevalent in more than 40% of all the cases with verified LBs regardless of clinical diagnosis. CONCLUSION: Consecutive dementia cases, fulfilling the clinical consensus criteria for DLB, may exhibit combinations of neuropathological changes which in themselves can explain the clinical picture of DLB even when LBs are absent.     

Neuropathologic study of 50 cases of senile dementia

Fifty brains from patients prospectively studied in a geriatric hospital (Charles Richet Study) were examined pathologically. The patients were senile (mean age: 85) and demented and had been clinically diagnosed as senile dementia of Alzheimer type (SDAT), vascular or multi-infarct dementia (VD), mixed dementia (MD). The whole brain was studied after formalin fixation and coronal sections. The senile changes were quantified in 6 neocortical areas, hippocampus and amygdala and subcortical structures after staining by thioflavine--S and Bodian's method. The other vascular and degenerative lesions were semiquantitatively studied. Three groups of patients were identified after microscopic examination: 1. SDAT (n = 27), 2. VD (n = 6), 3. MD (n = 15), 2 patients had no significant pathological correlate for dementia. Comparison of thioflavine S and Bodian's method in 30 cases showed the former to be more sensitive for the identification of senile plaques. In SDAT, 13/27 brains lacked neurofibrillary tangles in the neocortex. Amyloid angiopathy was observed in 78% of the brains but lacked in 5/6 cases affected by pure VD. Significant lesions of the substantia nigra were observed in 13 cases with typical features of Parkinson's disease in 2 cases. The locus coeruleus was affected mainly in SDAT cases (20/27) and in some cases of VD or MD (6/21). The raphe nuclei showed neuronal loss in 18% of the cases, mostly SDAT. In this series of cases, neocortical neurofibrillary tangles could be lacking in SDAT. Amyloid angiopathy was almost always present in SDAT and MD. Subcortical structures involved in cholinergic, noradrenergic and serotoninergic innervation of the cortex were more severely impaired in SDAT and MD than in VD. Mixed dementia was frequent in these very old demented patients. Clinical and pathological criteria are needed to identify this group of patients.     

Clinical Lewy body dementia and the impact of vascular components

OBJECTIVE: To study the prevalence of patients fulfilling the clinical consensus criteria for dementia with Lewy bodies (DLB) in a dementia population followed up with postmortem examination. To compare the clinical and neuropathological findings in the clinical Lewy body dementia (LBD) group with findings in a clinically defined group with Alzheimer's disease (AD). DESIGN: Medical records from 200 patients were studied retrospectively. Clinical consensus criteria for DLB and clinical criteria for other dementias were applied. SETTING: The majority of the cases were examined and cared for in psychogeriatric and psychiatric departments. PATIENTS: The patients, who died between 1985 and 1994, were part of a longitudinal dementia project. Each case was neuropathologically examined. Main outcome measures Prevalence of clinical signs and neuropathology was compared between the clinical groups. RESULTS: Forty-eight (24%) patients fulfilled the clinical criteria for DLB while 45 (22%) fulfilled the clinical criteria for Alzheimer's disease. The clinical LBD group had a higher Hachinski score compared to the clinical AD group. They also showed a tendency towards a 'frontal profile' with disinhibition, confusion, personality change and vocally disruptive behaviour. More than 80% of the AD and LBD groups respectively exhibited Alzheimer pathology. The LBD group had frontal white matter pathology and degeneration of the substantia nigra more often than the clinical AD group. Both LBD and AD groups showed a progressive and marked increase in severity of dementia and decrease in ADL capacity according to an evaluation based on the Berger scale and Katz index. The condition of the LBD group was significantly worse earlier in dementia. CONCLUSION: The results of this study indicate that patients fulfilling the clinical criteria for DLB also exhibit clinical features of possible vascular origin and a frontal profile. Subcortical vascular pathology, nigral degeneration and AD pathology in this group could partly explain the clinical features used to define DLB.     

Interleukin-6 is present in early stages of plaque formation and is restricted to the brains of Alzheimer's disease patients

Interleukin-6 (IL-6) immunoreactivity has previously been shown in plaques in Alzheimer's disease (AD) and elevated IL-6 concentrations have been measured biochemically in brains of AD patients. In this study, we investigated the appearance of IL-6 immunoreactivity in AD plaques according to the stage of plaque formation. Using the Bielschowsky silver-staining method, we were able to differentiate between four types of plaques described earlier: diffuse, primitive, classic and compact. While diffuse plaques represent the early stage of plaque formation, primitive and classic plaques are thought to represent later stages of plaque development. We investigated serial sections of paraffin-embedded cortices of ten clinically diagnosed and histopathologically confirmed AD patients and ten patients with no clinical history of dementia. We found plaques in the brains of both nondemented and demented persons using the silver staining method or immunohistochemistry with antibodies against the amyloid precursor protein. In the group of clinically nondemented persons, diffuse plaques were the predominant plaque type, whereas primitive plaques formed the larger portion of lesions in the group of AD brains. IL-6 could not be detected in plaques of patients without dementia. Many IL-6-positive plaques were found in six of the AD brains and to a smaller extent in the other four AD cases. In the six cases with a large number of IL-6-positive plaques, IL-6 was found in a significantly higher ratio of diffuse plaques than expected from a random distribution of IL-6 in all plaque types. We conclude from these findings that IL-6 immunoreactivity correlates with clinical dementia and that in AD patients, an IL-6-related immunological event may contribute to plaque formation. IL-6 might be involved both in the transformation from diffuse to primitive plaques in AD as well as in the development of dementia.     

Severe cerebral amyloid angiopathy characterizes an underestimated variant of vascular dementia

Cerebral amyloid angiopathy (CAA) is a frequent finding on neuropathological examination of patients with Alzheimer's disease (AD). A recent study from our laboratory showed that CAA also frequently occurred in vascular dementia with additional mild Alzheimer encephalopathy (VaD-ae, i.e. Alzheimer pathology that does not fulfill criteria for AD). Because CAA is associated with cerebral hemorrhages and infarctions, it is of significant interest to confirm or dismiss the hypothesis that CAA contributes clinically in the many patients that present with VaD-ae. Therefore, we examined entire temporal lobes of 11 VaD-ae cases and 11 age-matched AD cases with Abeta immunohistochemistry. Six of 11 VaD-ae cases had severe CAA, more extensive than in any AD case. There was a trend toward more cortical infarctions in this group, indicating that CAA in VaD may be of clinical importance and an underestimated cause of dementia.     

Alpha-synuclein cortical Lewy bodies correlate with dementia in Parkinson's disease

BACKGROUND: Dementia is a frequent complication of idiopathic parkinsonism or PD, usually occurring later in the protracted course of the illness. The primary site of neuropathologic change in PD is the substantia nigra, but the neuropathologic and molecular basis of dementia in PD is less clear. Although Alzheimer's pathology has been a frequent finding, recent advances in immunostaining of alpha-synuclein have suggested the possible importance of cortical Lewy bodies (CLBs) in the brains of demented patients with PD. METHODS: The brains of 22 demented and 20 nondemented patients with a clinical and neuropathologic diagnosis of PD were evaluated with standard neuropathologic techniques. In addition, CLBs and dystrophic neurites were identified immunohistochemically with antibodies specific for alpha-synuclein and ubiquitin; plaques and tangles were identified by staining with thioflavine S. Associations between dementia status and pathologic markers were tested with logistic regression. RESULTS: CLBs positive for alpha-synuclein are highly sensitive (91%) and specific (90%) neuropathologic markers of dementia in PD and slightly more sensitive than ubiquitin-positive CLBs. They are better indicators of dementia than neurofibrillary tangles, amyloid plaques, or dystrophic neurites. CONCLUSION: CLBs detected by alpha-synuclein antibodies in patients with PD are a more sensitive and specific correlate of dementia than the presence of Alzheimer's pathology, which was present in a minority of the cases in this series.     

Substance P immunoreactivity in Alzheimer disease: a study in cases presenting symmetric or asymmetric cortical atrophy.

Substance P-like immunoreactivity was visualized by immunohistochemical methods in 20 postmortem brains: 6 senile, 4 presenile Alzheimer dementia (AD), 3 AD with interhemispheric asymmetric cortical atrophy, and 7 control cases. For all pathological cases, the SP-like immunoreactivity was significantly reduced in the neocortical areas and in the hippocampus. This contrasted with an enhanced SP-like immunoreactivity in the pallidum and the substantia nigra in AD brains and a more pronounced SP-like immunoreactivity in the more atrophic side in the asymmetrically atrophied brains.     

Dementia, gliosis and expression of the small heat shock proteins hsp27 and alpha B-crystallin in Parkinson's disease.

Cognitive impairment and dementia are common in the later stages of Parkinson's disease (PD). Neuropathological examination of demented PD (PDD) patients often reveals changes that are typical of Alzheimer's disease (AD). In AD, there is a massive reactive gliosis and increased expression of the small heat shock proteins (hsp) hsp27 and alpha B-crystallin. Since these proteins are characteristic for reactive astrocytes in AD, we investigated their expression in the brains of PDD patients. The results were compared with those obtained in the brains of non-demented PD patients. We found (1) no detectable expression of hsp in PD without dementia, and low expression in PD with mild dementia; (2) reactive gliosis and increased expression of hsp in the cortex of PDD brains; (3) a strong association between hsp immunoreactivity and the severity of the AD-specific changes, especially with the number of tangles in the hippocampus; (4) a distinct immunoreaction of alpha B-crystallin in microglia in the substantia nigra and in the hippocampus in PDD. These results indicate that astrocytes react to the disease conditions in AD and in PDD in a similar way, namely by the increased expression of small heat shock proteins, and present additional evidence for the thesis that the pathology of the dementia in PD is related to that in AD.     

Nuclear factor kappa-B p50 and p65 subunits expression in dementia with Lewy bodies

Dementia with Lewy bodies (DLB) is the second most common cause of neurodegenerative dementia after Alzheimer's disease (AD). Parkinsonism in DLB is mainly caused by neuronal loss with Lewy bodies (LBs) in the substantia nigra, thereby inducing degeneration of the nigrostriatal dopaminergic pathway similar to that in Parkinson's disease (PD). To clarify the pathogenesis of DLB, it is important to investigate the mechanisms involved in the degenerative process of LB-bearing neurones. Several reports suggest a role for nuclear factor kappa-B (NFkappaB) in the manifestation of neurodegenerative conditions such as AD and PD. The aim of the present study was to investigate whether NFkappaB subunits are involved in the pathogenesis of neurodegeneration in DLB by measuring tyrosine hydroxylase (TH), NFkappaB p65 and p50 protein expression in frontal cortex and substantia nigra pars compacta of DLB and control human brains. An increase, although not statistically significant, in nigral TH expression in DLB cases was observed. There were no differences in the cortical and nigral expression levels of NFkappaB p65 subunit between control and DLB cases. Western blots of the frontal cortex showed no differences in the expression levels of NFkappaB p50 subunit. However, NFkappaB p50 levels were significantly decreased (P < 0.05) in the pars compacta of the substantia nigra in the DLB cases in comparison with controls. The decrease in the expression of the p50 subunit in the substantia nigra of DLB cases achieved in the present study may increase the vulnerability of the dopaminergic neurones to a possible neurotoxic effect of p65 subunit. Thus, normal levels of NFkappaB p65 might be toxic in neurones with a low expression of the NFkappaB p50 subunit.     

Cerebral amyloid angiopathy and cognitive function: the HAAS autopsy study

OBJECTIVE: To investigate the relationship between cerebral amyloid angiopathy (CAA), dementia, and cognitive function in an autopsy sample of 211 Japanese-American men from the population-based Honolulu-Asia Aging Study. METHODS: Starting in 1991, participants were assessed with the Cognitive Abilities Screening Instrument (CASI) and diagnosed with dementia (including subtype) based on published criteria. At autopsy, neuropathologists blinded to clinical data examined brains for neurofibrillary tangles (NFT), neuritic plaques (NP), and a number of vascular pathologies, including CAA. CAA was detected by immunostaining for betaA4 amyloid in parenchymal vessels in the neocortex and semiquantitatively rated. Linear regression models were used to examine the association of CASI score, dementia subtype, and CAA controlling for age at death, time between CASI administration and death, education, NP and NFT counts, infarcts, hemorrhage, and APOE genotype. RESULTS: A total of 44.1% of subjects had CAA in at least one neocortical area. The presence of CAA was associated with higher mean NFT and NP counts and having at least one APOE-epsilon4 allele. The interaction between CAA and AD on the adjusted mean CASI score was significant; compared with nondemented men without CAA, the CASI score was 16.6% lower in men with AD and no CAA and 45.9% lower in men with AD plus CAA. CONCLUSIONS: CAA may contribute to the clinical presentation of dementia by interacting with other neuronal pathologies, leading to more severe cognitive impairment in men with both CAA and AD compared with men with only AD or CAA.     

Complications of severe cerebral amyloid angiopathy in the course of dementia with Lewy bodies. A case report

A 68-year-old male who suffered from dementia, progressing for four months without Parkinson's symptoms, was admitted to the Department of Neurology because of vertigo, slight left hand paresis and positive Romberg test. During hospitalization the patient's status deteriorated. The intracerebral lobar haemorrhage, subarachnoid haemorrhage and ischaemic lesions observed on CT scans suggested the clinical diagnosis of CAA. He died after 53 days due to pneumonia. On macroscopic examination, the brain showed general cortical atrophy and ventricular dilatation. Frontal lobar haemorrhage and focal subarachnoid haemorrhage were seen on the brain autopsy. Microscopic observation demonstrated neuronal loss and microspongiosis in the hippocampus, severe neuronal loss and depigmentation in the substantia nigra pars compacta and locus coeruleus. Lewy bodies were visible in the substantia nigra and amyloid angiopathy, predominantly severe CAA according to the Vonsattel scale, in the meningeal and cortical vessels. In the presented case, the microscopic findings were typical for DLB with concomitant severe CAA. In progressive dementia, neurological deterioration, presence of lobar hemorrhagic infarcts and ischaemic lesions suggest CAA coexistent with DLB and/or AD.     

Observations of amyloid angiopathy and senile plaques by the scanning electron microscope

Summary Blood vessels with amyloid angiopathy and senile plaques in the cortices of the brains with Alzheimer's disease and senile dementia were observed by means of a scanning electron microscope.The results obtained were as follows: The blood vessels with amyloid angiopathy were surrounded by solid substances. The senile plaques consisted of rough solid substances, contained degenerated cell processes, and almost all plaques existed around the degenerated capillaries with amyloid angiopathy.From the above described findings, we suggest that the senile plaque has an extremely close relationship to the capillary which had undergone amyloid angiopathy.     

Clinical Features of Pittsburgh Compound-B-Negative Dementia

Background/Aims: We previously found that some cases of clinically diagnosed Alzheimer's disease (AD) were rated as Pittsburgh compound B (PiB) negative by amyloid imaging (i.e. cases of PiB-negative dementia). The present study was designed to analyze the clinical features of PiB-negative dementia patients in detail. Methods: Of the 64 cases of clinically diagnosed AD, 14 were rated PiB negative. Eleven of these were further analyzed using CSF biomarker levels and findings from MRI, FDG-PET, (123)I-MIBG myocardial scintigraphy and voxel-based morphometry (VBM). Results: When examined by (123)I-MIBG myocardial scintigraphy, the heart/mediastinum ratio was significantly higher in the PiB-negative dementia group than in the dementia with Lewy bodies (DLB) group. Analyses of CSF biomarkers and MRI and FDG-PET findings suggested argyrophilic grain disease (AGD) in 3 cases, frontotemporal lobar degeneration (FTLD) in 3 cases, neurofibrillary tangle-predominant dementia (NFTD) in 1 case, and AD in 2 cases. In the VBM data analysis, the PiB-positive AD group showed significant atrophy of both hippocampi compared with the healthy control group, while the PiB-negative dementia group presented with significant atrophy of the left precuneus. Conclusion: PiB-negative dementia is unlikely to include DLB, while it most likely includes diseases of tauopathy, such as FTLD, AGD and NFTD. A better understanding of PiB-negative dementia is expected to further improve the accuracy of the clinical AD diagnosis.