Quantitative MRI findings and cognitive impairment among community dwelling elderly subjects

OBJECTIVES

To study the factors which influence cognitive impairment among elderly subjects living in a local community, based on both MRI and clinical findings, to further elucidate the causes of dementia, and also to help develop strategies for its prevention.

METHODS

Cranial MRI and other medical examinations were performed on non-demented elderly subjects who resided in one rural community. A total of 254 subjects aged from 60 to 91 years of age, with a mean age of 73.9 (SD 6.8) were examined. The mini mental state examination (MMSE) was used to identify cognitive impairment. White matter lesions and cerebral atrophy on MR images were measured quantitatively. A multivariate analysis was also performed with the existence of cognitive impairment as the dependent variable, and the MRI findings and clinical observations were used as the independent variables.

RESULTS

Cognitive impairment was present in 46 subjects (18.1%). They were older, had a lower educational level, and more frequent hypertension compared with those without cognitive impairment. The packed cell volume was lower in the impaired group. In addition, their MRI findings showed significantly larger quantities of white matter lesions and cerebral atrophy, as well as more infarcts. A logistic regression analysis demonstrated a significant relation among such factors as white matter lesions (odds ratio (OR) 1.575, 95% confidence interval (95% CI) 1.123-2.208), cerebral atrophy (OR 0.761, 95%CI 0.587-0.987), and lower education (OR 0.682, 95%CI 0.544-0.855) for subjects with a cognitive impairment.

CONCLUSIONS

White matter lesions and cerebral atrophy are factors which induce a cognitive impairment in community dwelling elderly subjects without dementia. It is important to carefully watch for any abnormalities in these factors, and to perform cohort studies to check for the above risk factors, to both prevent and make an early diagnosis of dementia.

Apoptotic bodies in the cerebellum of Japanese patients with Creutzfeldt-Jakob disease

The aim of this study was to provide morphological evidence for neuronal apoptosis in Creutzfeldt-Jakob disease (CJD) using hematoxylin-eosin (HE)-stained specimens. A microscopic examination showed typical apoptotic bodies were found in the granular layer of the cerebellum in 13 of 14 Japanese patients with CJD, while no apoptotic bodies were observed in any other areas of the examined CJD brains. Most of the fragmented nuclei of the apoptotic cells were labeled by in situ end-labeling of fragmented DNA, terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick-end labeling. To the authors' knowledge, this is the first report demonstrating neuronal apoptotic bodies in the human neurodegenerative disorders on HE-stained sections. The present findings indicate that apoptosis plays a major role in the neuronal loss of the cerebellar granule cells in CJD.

Relationship between both IQ and Mini-Mental State Examination and the regional cerebral glucose metabolism in clinically diagnosed Alzheimer's disease: a PET study

In order to clarify the hypofunction in which brain areas demonstrate a decline in Intelligence Quotient (IQ), we examined correlations between the IQ and Mini-Mental State Examination (MMSE) and regional cerebral metabolic rate of glucose (rCMRglc) measured using positron emission tomography (PET) in 26 patients with clinically diagnosed Alzheimer's disease (AD). The MMSE scores and full-scale IQ (FSIQ) showed significant correlations with the rCMRglc in the temporal and parietal lobes on both sides and in the left frontal lobe, which were significantly reduced in comparison to those in the normal controls. A multiple regression analysis showed only the MMSE score to predict verbal IQ (VIQ), performance IQ (PIQ) and FSIQ. VIQ was also predicted by the rCMRglc in the left parietal lobe, while PIQ was predicted by the age at onset. The results suggested MMSE to be an index of dementia severity reflected by general intelligence as shown by IQ in AD, and a reduction in the VIQ can thus be used as an index of the left parietal dysfunction, which is not expressed by MMSE.

Enhanced CD9 expression in the mouse and human brains infected with transmissible spongiform encephalopathies

A tetraspan protein CD9, normally expressed in the myelin sheath of the central and peripheral nervous system, was identified to be up-regulated in mouse brains infected with transmissible spongiform encephalopathy (TSE), by mRNA differential display screening. To elucidate its role in the neurodegeneration process observed in TSE, CD9 expression was examined in the murine disease model and in the human disease materials. Up-regulation of CD9 gene expression in the TSE-infected mouse brains was detected as early as a preclinical stage, when abnormal prion protein deposition and vacuolation were obviously manifested in the internal capsule and thalamus. In contrast, other myelin protein genes showed a reverse pattern of CD9 gene expression. Enhanced CD9 expression was immunohistochemically detected in the astrocytes of such pathological regions. In human specimens of TSE, enhanced CD9 immunoreactivity was observed in the astrocytes and some oligodendrocytes in the brains, but no relevant alteration in CD9 immunoreactivity was observed in the other organs or tissues. Positive CD9 immunoreactivity in astrocytes was also manifest in other neurological disorders in a less prominent manner. The findings indicate that up-regulated CD9 plays a role in glial cells in pathological conditions, especially in such a devastating condition as TSE.

Sex-related differences in the muscarinic acetylcholinergic receptor in the healthy human brain--a positron emission tomography study

We evaluated the sex-related differences in the decline of the cerebral muscarinic acetylcholinergic receptor (mACh-R) due to aging by using 11C-N-methyl-4-piperidyl benzilate (11C-NMPB) and positron emission tomography (PET). The subjects consisted of 37 (20 males and 17 females) healthy volunteers. The 11C-NMPB uptake was evaluated by the ratio method (regional 11C-NMPB uptake/Cerebellar 11C-NMPB uptake; rNMPB ratio). The correlation between sex, aging, and the rNMPB ratio in normal aging was evaluated by a multiple regression analysis. The rNMPB ratio was higher in females than in males throughout the entire cerebral region (p < 0.01-p < 0.0001) and the rNMPB ratio might thus possibly decline with age more rapidly in females. Our study therefore revealed the existence of sex-related differences in the cerebral mACh-R.

Novel intronic polymorphisms in the presenilin-2 gene and a case-control association study of Alzheimer's disease

Several alleles of introns or untranslated regions in the presenilin-1 (PS-1) and presenilin-2 (PS-2) genes have been reported to behave as risk factors for senile Alzheimer's disease (AD). On the other hand, mutations in the three presenile AD genes also have been identified in a small number of sporadic presenile AD and senile AD cases. The present study evaluated the genetic contributions of PS-2 exons and introns to 56 senile and 18 Japanese cases of presenile AD using polymerase chain reaction single-strand conformation polymorphism analysis. In the PS-2 gene, one exonic polymorphic site without amino acid substitution, 9 intronic polymorphic sites, and 2 intronic variant sites were detected. However, in all cases, amino acid substitutions in exons between 4 and 12 of the PS-2 gene were not observed. The risk factors of senile and presenile AD were evaluated using a population-based study of restriction cleavages between patients and controls in introns 3, 4, 10 and 11. Regarding PS-2, there was no association between AD and intronic polymorphisms.

Skein-like inclusions in the neostriatum from a case of amyotrophic lateral sclerosis with dementia

Skeins or skein-like inclusions (SLIs) in motor neurons detected by ubiquitin immunohistochemistry are a characteristic finding of amyotrophic lateral sclerosis (ALS). Here we report ubiquitinated SLIs in the putamen and caudate nucleus from a case of ALS with dementia. A 48-year-old Japanese man developed apathy and amimia. Mental and neurological examinations revealed severe character change, muscle atrophy and fasciculation of the distal upper extremities and the tongue, and an exaggeration of the deep tendon reflex. He subsequently showed dysphagia and dysarthria. He died at the age of 51 years, after a total clinical course of about 2.5 years. By immunohistochemistry, ubiquitin-immunoreactive intraneuronal inclusions were observed in the spinal anterior horn cells, the frontal, temporal and entorhinal cortices, dentate fascia of the hippocampus and the amygdala. In addition, ubiquitinated inclusions were also seen in the putamen and caudate nucleus, which appeared as aggregates of thread-like structures similar to SLIs in the spinal anterior horn neurons. They were not seen on hematoxylin-eosin staining, and they also did not show any argentophilia nor did they react with other antibodies, including antibody against tau protein. To our knowledge, this is the first report of the presence of SLIs in non-motor neurons. Our results thus support the notion that ALS is a multisystem disease, and not simply a disease of the motor neurons.

Cerebral muscarinic acetylcholinergic receptor measurement in Alzheimer's disease patients on 11C-N-methyl-4-piperidyl benzilate--comparison with cerebral blood flow and cerebral glucose metabolism

We studied the cerebral muscarinic acetylcholinergic receptor (mACh-R) by means of 11C-N-methyl-4-piperidyl benzilate (11C-NMPB) and positron emission tomography (PET) in Alzheimer's disease (AD) cases, and the findings were compared with the cerebral blood flow (CBF) and the glucose metabolism (CMRGlc) to evaluate the relationship between the mACh-R and the CBF or the CMRGlc. The subjects consisted of 18 patients with AD and 18 age and sex matched normal volunteers. The patients were clinically diagnosed according to the criteria of the NINDS-ADRDA as having "probable AD" and were thus classified into two groups (mild and moderate AD) according to the severity of dementia determined by DSM-III-R. The CBF was measured by 99mTc-HMPAO SPECT, and the CMRGlc was measured by 18FDG PET. The 11C-NMPB uptake was evaluated by the graphical method and the ratio method (ROIs/Cerebellum). A significant mACh-R decrease and more severe CMRGlc decrease in the cortical region was seen in mild and moderate AD. The decrease in the CBF was not as obvious as that in the mACh-R and the CMRGlc. Our study thus suggested that the mACh-R decreased in patients with AD, and that the 18FDG PET was the most sensitive method for detecting the degenerative regions in patients with AD.

Relationship of emotional behaviors induced by electrical stimulation of the hypothalamus to changes in EKG, heart, stomach, adrenal glands, and thymus

The relationships of hypothalamically elicited emotional behaviors to their accompanying pathophysiological effects were examined as a model of how complex "emotional behaviors" may be related to fundamental psychosomatic disorders. Twenty-two unanesthetized adult cats were studied. EKG alterations and histological changes in the heart, stomach, adrenal glands, and thymus were related to the specific stereotypical emotional behaviors that could be elicited by hypothalamic stimulation in tamed subjects. Restlessness, threat, and searching-biting behaviors were evoked by electrical stimulation of the anteromedial, ventromedial, and lateral hypothalamus, respectively. The occurrence of cardiac arrhythmias, ST and/or T (ST-T) changes in the EKG, histological damage to myocardium, gastric erosion, and adrenal hyperplasia were generally observed in the restlessness and threat groups but not in the searching-biting group. The pathophysiological effects were similar in the restlessness and threat groups with no specific EKG change or organ effect attributable to either site of stimulation. Hypothalamically elicited restlessness or threat behaviors in cats are each associated with cardiac, gastric, and adrenal pathophysiologies.

Allelic variation of apolipoprotein E in Japanese sporadic Creutzfeldt-Jakob disease patients

We analyzed apolipoprotein E (apo E) genotypes in 53 Japanese sporadic Creutzfeldt-Jakob disease (CJD) patients and 100 normal controls using the polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) methods. The apo E allelic frequencies in Japanese sporadic CJD patients and our control population were as follows: epsilon 2, 6.6% versus 7.5%; epsilon 3, 82.1% versus 81.5%; epsilon 4, 11.3% versus 11.0%. The mean ages at onset in Japanese sporadic CJD patients were as follows: epsilon 3/epsilon 3, 63.8 years; epsilon 3/epsilon 4, 66.3 years; epsilon 2/epsilon 3, 68.6 years. These results indicate that there is no association between apo E genotype and sporadic CJD in Japan.

A synthetic peptide deduced from the sequence in the cross-region of laminin A chain mediates neurite outgrowth, cell attachment and heparin binding

Synthetic peptides from the cross-region of the laminin A chain were prepared and tested for their biological activities, especially for neurite outgrowth. A synthetic 8-mer peptide (designated LMA-5) in the cross-region of the laminin A chain was found to promote neurite outgrowth in PC12 cells and cerebellar microexplant cultures. Furthermore, this peptide mediated cell attachment and heparin binding. In addition, an antibody against peptide LMA-5 inhibited laminin- and LMA-5-mediated cell attachment. This antibody also inhibited more than half of the LMA-5-promoted neurite outgrowth in cerebellar microexplant cultures. These data suggest that peptide LMA-5 is one of the active sites in laminin that regulate cell behaviour including neurite outgrowth, cell attachment and heparin binding.

Distribution of prion protein in German patients with Creutzfeldt-Jakob disease is different from that in Japanese patients

We investigated the distribution of prion protein (PrP) in 14 German patients with sporadic Creutzfeldt-Jakob disease (CJD) and compared it with that observed in Japanese patients. Immunohistochemical study revealed diffuse gray matter stainings including synaptic structures in all cases. In addition, 4 patients showed plaque-type deposition which was very rarely observed among sporadic Japanese patients without known mutation of the PrP gene but with valine at codon 129. A higher incidence of PrP plaques in German sporadic CJD may be related to the racial difference in the PrP gene.

Comparison of silver stainings and immunohistology for the detection of neurofibrillary tangles and extracellular cerebral amyloid in paraffin sections

The sensitivities of six silver-staining methods and immunohistology for beta and tau protein were compared for their ability to demonstrate neurofibrillary tangles (NFT) and senile plaques (SP) in paraffin sections. Serial sections of the hippocampal area of 35 brains showing these neuropathological findings were cut and stained by the methods of Cross, Campbell, Bielschowsky, Gallyas, Yamaguchi, our variant (method of Reusche) and immunohistology. In the detection of NFT, the techniques of Gallyas, Bielschowsky, our method and tau protein immunostaining were the most sensitive methods. The procedure of Campbell and again our method were proven to be superior to the other stainings in demonstrating SP as well as diffuse and subpial amyloid. Moreover, our method reliably stained vascular and perivascular amyloid which can be identified in brains with congophilic angiopathy. Due to a lack of control in certain steps of the procedures most of the silver-staining methods are complicated and to not present reliable results. Our variant is easy to perform and, thus, may be used as a sensitive, simple and reliable alternative for the impregnation of the main lesions (NFT and SP) occurring in senile dementia of Alzheimer type and brains with normal aging for screening, retrospective and quantitative studies and for routine purposes.

Amyotrophic lateral sclerosis and frontal lobe dementia in Alzheimer's disease. Case report and review of the literature

Clinicopathological data of a woman with a 3-year course of concurrent amyotrophic lateral sclerosis and dementia are presented. Dementia had occurred at time of onset of motor disturbances and presented as typical frontal lobe dementia. Pathology confirmed motor neuron disease of amyotrophic lateral sclerosis and frontal lobe atrophy. Multiple senile plaques were distributed cortically and in the hippocampus, where diffuse spread of neurofibrillary tangles was seen. Hence, this Alzheimer's dementia in a patient with sporadic amyotrophic lateral raises the question of a possible association between the two conditions.

Electron microscopic study of paired helical filaments and cerebral amyloid using a novel en bloc silver staining method

A one step en bloc silver staining method which was originally established to study nucleolar organizer regions has been applied for the demonstration of both paired helical filaments (PHF) and extracellular cerebral amyloids in semi-thin sections and at the electron microscopic level. The three forms of PHF can be visualized: (1) neurofibrillary tangles are shown in all stages from first appearance in form of intracellular patches of PHF to severely degenerated shadow-like "ghost" tangles; (2) neuropil threads are distinctly stained in great numbers; and (3) PHF are easily detected as neuritic components in amyloid plaques. All forms of fibrillar extracellular amyloid structures, i.e. "diffuse", "classical" and "burnt out" plaques, are well demonstrated; congophilic angiopathy reveals amyloid preferentially in arteries and arterioles of the leptomeninges and cortex ranging from small circumscribed patches to large circumferential amounts with occasional plaque-like condensations or broad loose accumulations of amyloid; perivascular cuffs and laminar subpial deposits of amyloid are stained as well. At the electron microscopic level all lesions are clearly visible in non uranyl/lead-stained specimens, characterized by varying numbers of silver grains on a pale background. The detailed demonstration of structures in archival material, which had been stored in paraffin and re-embedded for electron microscopy, is due to the demonstration of argyrophilic structures by the protective colloidal developer of gelatin and formic acid and to the proteolytic resistance of insoluble PHF and extracellular amyloids in plaques and congophilic angiopathy.

Accumulation of alpha B-crystallin in brains of patients with Alexander's disease is not due to an abnormality of the 5'-flanking and coding sequence of the genomic DNA

alpha B-Crystallin is a major protein component of Rosenthal fibers, which massively accumulate in the brains of patients suffering from Alexander's disease. To examine whether or not accumulation of alpha B-crystallin is due to any abnormality of the gene structures, we determined the sequence of the alpha B-crystallin gene in two cases of pathologically confirmed Alexander's disease. Direct sequencing of the promoter and coding regions of the alpha B-crystallin gene in patients revealed them to have a normal sequence. Northern blotting showed a single alpha B-crystallin mRNA species expressed in the Alexander's disease brain.

Increased senile plaques without microglia in Alzheimer's disease

To clarify the association of microglia with senile plaques, the brains from 13 patients with Alzheimer's disease (AD) and 23 nondemented aged controls were investigated immunohistochemically by a double-labeling method using anti-beta-protein antiserum and anti-ferritin antibody, which is a recently reported microglia marker. In addition, a quantitative analysis was performed. The senile plaques which appeared initially in the nondemented aged controls consisted of a diffuse type without any amyloid cores and these were found in the group aged 50-59 years. The great majority of them were found to contain no ferritin-positive microglia. The number and proportion (percentage) of microglia-containing diffuse plaques increased with age. Classical and compact plaques began to appear in the brains of the group aged 70 years and over, and practically all of them contained microglia. These results suggest that microglia are not associated with initial plaque formation, but correlate with amyloid core formation. In AD, the most prominent feature was that the diffuse plaques, which contained either no or only a few ferritin-positive microglia, increased markedly.

Increased tau accumulation in senile plaques as a hallmark in Alzheimer's disease

To identify the tau component in senile or kuru plaques, the authors examined brain sections from 12 patients with Alzheimer's disease (AD), 6 with Creutzfeldt-Jakob disease (CJD), and 20 nondemented aged controls using anti-beta protein, anti-buman prion protein, and affinity-purified tau-specific antibody. The tau component was identified both in senile and kuru plaques. In AD, tau-positive senile plaques were found in all cerebral cortices of almost all cases, and the tau-positivity of plaques in cerebral cortices was 5.1 to 27.5%. In CJD, tau-positive senile and kuru plaques were restricted to the hippocampus, and the tau-positivity was 4.3 and 1.2%, respectively. In nondemented aged controls, tau-positive senile plaques also were restricted mostly to the hippocampus, and the tau-positivity was 1.3%. Significant differences in the tau-positivity of senile plaques were found between AD and CJD and nondemented aged controls, and no significant differences were found between CJD and nondemented aged controls. These observations are important because increased tau accumulation in senile plaques can be a hallmark of AD.

Accumulation of lysosulfatide (sulfogalactosylsphingosine) in tissues of a boy with metachromatic leukodystrophy

Abnormal accumulation of lysosulfatide (sulfogalactosylsphingosine) was evident in autopsied tissues from a boy with late-infantile metachromatic leukodystrophy. The concentration was high in the cerebral white matter, spinal cord and sciatic nerve (116-787 pmol/mg protein) and low in the cerebral gray matter, kidney and liver (4-40 pmol/mg protein). As is the case with galactosylsphingosine, lysosulfatide inhibited cytochrome c oxidase activity, in a dose-dependent manner. Judging from the tissue distribution of the accumulated lysosulfatide and because of the cytotoxicity, the lysosulfatide presumably explains the demyelination seen in the nervous tissues of patients with metachromatic leukodystrophy.

Beta-protein amyloid is widely distributed in the central nervous system of patients with Alzheimer's disease

To clarify the distribution, morphology, and density of amyloid deposits in patients with Alzheimer's disease (AD), tissue sections from various areas of the central nervous system of 14 patients with AD and from 20 nondemented aged controls were investigated immunohistochemically using anti-beta protein antiserum. beta-protein amyloid deposits were present not only in the cores of the senile plaques and in the vascular wall (amyloid angiopathy), but also in various sized plaque-shaped fibrillary, perivascular, subpial, and subependymal deposits. Amyloid deposits were found mainly in the cerebral cortex in nondemented controls, while in AD they were distributed widely in the regions that were not affected in nondemented controls. The positivity of amyloid deposits in AD was 100% in the cerebral cortex, hippocampus, amygdala, thalamus, caudate nucleus, claustrum, hypothalamus, nucleus basalis of Meynert, and cerebellar cortex. Putamen and brain-stem nuclei were affected frequently, and the spinal cord, dentate nucleus, and globus pallidus were sometimes (less than 50%) affected. This result provides an evidence that Alzheimer's disease is a beta-protein amyloidosis of the central nervous system. An assessment of the distribution of amyloid deposits should prove to be useful for the histopathologic diagnosis of AD.

Aging and cerebral amyloid: early detection of amyloid in the human brain using biochemical extraction and immunostain

To search for relationships between aging and cerebral amyloid, the brains of 66 clinically nondemented individuals were investigated, using the following three approaches for verification of the amyloid: Congo red staining as a histochemical method; immunostaining using anti-beta protein antiserum as an immunohistochemical identification; and biochemical extraction of amyloid from nonfixed brain tissues. That the incidence of cerebral amyloid increased with aging was determined using all three approaches. Immunostaining using anti-beta protein antiserum was more sensitive than Congo red staining. The biochemical extraction was most sensitive for detection of amyloid, and revealed that amyloid was extracted initially from more than half (67%) of the brains of 9 persons in their 50s and from almost all (97%) brains of 35 persons over 60 years of age. Amyloid was extracted even from brains in which amyloid deposits were not detected by histochemical or immunohistochemical methods. This result shows early appearance of the age-related cerebral amyloid.

Incidence and characterization of age related amyloid deposits in the human anterior pituitary gland

To identify amyloid deposits in the anterior pituitary gland, we have immunohistochemical, histochemical and alkaline Congo red staining. The anti-human P component reacted positively with these amyloid deposits, while antisera against prealbumin, AA type amyloid fibril protein and various anterior pituitary hormones were negative. A combination of Congo red and anti-human P component staining was most sensitive and reliable for detection of amyloid in the anterior pituitary glands of 300 randomly autopsied patients. Amyloid deposits increased in parallel with the age of the patients, however, they appeared earlier and more frequently than heretofore reported. Deposition of amyloid was seen initially in the 3rd decade and the positivity rate of amyloid deposits was 73% in the 5th decade. The histochemical characteristics of these pituitary amyloid deposits differed from those of cerebral and systemic deposits, particularly those found in the amyloid of senile systemic amyloidosis.

Formic acid pretreatment enhances immunostaining of cerebral and systemic amyloids

The purpose of this study was to design a method by which immunoperoxidase staining can be applied to formalin-fixed, paraffin-embedded tissue sections to demonstrate amyloid deposits in cerebral and systemic amyloidotic tissues. We used anti-prion protein, anti-beta-protein, anti-amyloid A, and anti-prealbumin antisera. The tissue sections were first treated with 100% formic acid for 5, 20, or 60 minutes and the unlabeled immunoperoxidase method (biotin-streptavidin system reagents) was used. This formic acid pretreatment enhanced immunoreactivity of the amyloid deposits which reacted positively with specific antiserum. The specificity of the immunostainings was well preserved. This method can also be used to demonstrate interspecies cross-reactivity, by using anti-human amyloid A and anti-scrapie hamster prion protein antisera, which stained negatively or faintly with amyloid deposits of heterogenous species. The technique is expected to reveal the buried epitopes of amyloid deposits in tissue sections.