Progression of clinical deterioration and pathological changes in patients with Alzheimer disease evaluated at biopsy and autopsy.

OBJECTIVES: To quantify the progression of senile plaques, neurofibrillary tangles, cerebral amyloid angiopathy, and microglial activation in the cortex and white matter of patients with Alzheimer disease evaluated at both biopsy and subsequent autopsy and correlate these changes with the progression of neurologic impairment. SETTING: Academic referral center for patient with Alzheimer disease. PATIENTS: Four patients meeting the clinical criteria for Alzheimer disease, enrolled in a pilot study for the evaluation of response to intracerebroventricular administration of bethanechol chloride. The patients were followed up until death occurred and autopsy was performed. RESULTS: All 4 patients had progressive deterioration from the time of biopsy to autopsy (9-11 years). Pathological investigations showed a striking increase in the density of senile plaques and neurofibrillary tangles in 2 of 4 patients from biopsy to autopsy, and a significant increase in microglial activation in 1 of 4 cases. Severity of cerebral amyloid angiopathy varied significantly among patients, 1 of whom displayed striking amyloid deposition with associated subcortical white matter atrophy. CONCLUSIONS: These unique data demonstrate that the progressive neurologic impairment in Alzheimer disease is accompanied by a significant increase in senile plaque and neurofibrillary tangle counts in the frontal cortex and, possibly in some patients, by increased microglial cell activation. Cerebral amyloid angiopathy was associated with significant white matter disease.

Giant cell arteritis in association with cerebral amyloid angiopathy: immunohistochemical and molecular studies.

Giant cell arteritis (GCA) usually manifests as a transmural vascular infiltrate of mononuclear and multinucleated giant cells (MNGC). We describe six patients with GCA associated with severe cerebral amyloid angiopathy (CAA), all with cerebral hemorrhage or varying degrees of cerebral infarct, and histological evidence of Alzheimer's disease (cortical CAA often predominating over senile plaques and neurofibrillary tangles). One case showed mostly cortical involvement (with old microhemorrhages), and the others were primarily leptomeningeal (with involvement of the underlying cortex and extensive encephalomalacia of adjacent brain). Many vessels with CAA exhibited a pronounced adventitial and perivascular infiltrate of lymphocytes, histiocytes, and MNGC. Immunohistochemical staining showed deposition of beta/A4 peptide primarily in the thickened media of CAA vessels, and within the cytoplasm of MNGC--suggesting phagocytosis of insoluble peptide. Cystatin C antibody stained vascular amyloid and diffusely highlighted astrocytic and MNGC cytoplasm. HAM56-positive macrophages were frequently seen around amyloid-laden vessels. Anti-smooth muscle actin immunohistochemistry suggests the occurrence of medial destruction by amyloid, with relative preservation of intimal cells. Ultrastructural studies performed in one case confirmed the presence of intracytoplasmic amyloid in MNGC. The GCA seen in these cases of CAA most likely represents a foreign body response to amyloid proteins, causing secondary destruction of the vessel wall. DNA from brain tissues of five affected patients was examined to assess whether mutations were present in exon 17 of the APP gene or exon 2 of the cystatin C gene, a finding that might explain the foreign body giant cell response to amyloid proteins in these cases. However, restriction fragment mapping of amplified gene segments showed that previously described mutations were not present in these cases.

Brain parenchymal and microvascular amyloid in Alzheimer's disease.

Brains of patients with Alzheimer disease/senile dementia of Alzheimer type (AD/SDAT) develop a progressive accumulation of amyloid, which deposits primarily in the form of characteristic parenchymal 'plaques' (senile or neuritic plaques/SP's) and as mural deposits in the walls of capillaries and arterioles (cerebral amyloid angiopathy /CAA). A major component of this amyloid is a small and unique peptide composed of 39-43 amino acids, beta/A4, which is cleaved from a much larger precursor protein (APP) that has several isoforms. Brain amyloid can be detected in autopsy or biopsy brain tissue by classical, immunohistochemical and ultrastructural (including immuno-electron microscopic) methods of varying sensitivity and specificity. Beta/A4 amyloid deposition is remarkably variable (e.g. predominantly parenchymal or vascular, or a mixture of parenchymal and vascular) among patients with AD/SDAT. Despite its abundance in the brains of AD/SDAT patients, the precise role of beta/A4 in the pathogenesis of the neurological deficit, neocortical atrophy and progressive synapse loss associated with AD/SDAT has yet to be determined. However, mutations in the gene that encodes APP are clearly associated with familial AD syndromes in which there is significant brain amyloid deposition. CAA, in addition to its association with AD/SDAT, can result in hemorrhagic and (possibly) ischemic forms of stroke. Work with recently developed transgenic mice which express large amounts of beta/A4 in the central nervous system is likely to elucidate mechanisms by which the protein is selectively or deposited in the brain in a parenchymal or microvascular form, and how it contributes to the pathogenesis of neurodegeneration.

Chronic encephalitis associated with epilepsy: immunohistochemical and ultrastructural studies.

Chronic encephalitis has been recognized as a cause of epilepsy since the work of Rasmussen et al. in the late 1950s. Despite this, few immunohistochemical studies of the affected brain tissue have been attempted. We have studied specimens of brain tissue from seven patients with this condition who underwent therapeutic multilobar cortical resection or hemispherectomy. Immunohistochemical studies were carried out using antibodies to glial fibrillary acidic protein (GFAP), proliferating cell nuclear antigen (PCNA, PC10), T lymphocytes (UCHL-1), B lymphocytes (L26), macrophages and microglia (HAM-56), and major histocompatibility complex molecules (LN3 and beta 2-microglobulin). Additionally, the results of preliminary immunohistochemical and ultrastructural investigation of possible immune complex deposition in blood vessel walls of affected brain tissue are presented. The pattern of GFAP immunoreactivity suggested a patchy and/or laminar disease process in most patients. GFAP immunoreactive cells were especially prominent around microvessels in some cases, suggesting an abnormality and perivascular collections of inflammatory cells, seen to a variable extent in all cases, contained abundant cells immunolabelled with UCHL-1, LN3 and beta 2-microglobulin. L26-labelled B lymphocytes were extremely sparse. Anti-PCNA frequently labelled microvascular endothelial cells, rare pericytes and occasional cells with microglial/macrophage morphology. The data suggest that chronic encephalitis found in patients with epilepsy results from patchy but widespread parenchymal brain injury, in the course of which cells of both microglial and lymphocyte series accumulate or proliferate within brain.(ABSTRACT TRUNCATED AT 250 WORDS)

Microvasculature in brain biopsy specimens from patients with Alzheimer's disease: an immunohistochemical and ultrastructural study.

Brain biopsy specimens from five patients with Alzheimer's disease obtained in the course of a trial of intracerebroventricular bethanechol were studied by immunohistochemical (antibody to A4 peptide) and ultrastructural techniques, with particular emphasis on the microvessels. In some cases, numbers of A4-immunoreactive lesions (senile plaques) correlated well with numbers of plaques demonstrable by silver stains. Prominent A4-immunoreactive amyloid angiopathy was seen in one patient. The patient with severe cerebral amyloid angiopathy (CAA) showed extensive arteriolar deposition of amyloid filaments with apparent destruction of the media but remarkably intact endothelium. A cell of origin for amyloid filaments was not apparent, although close proximity to smooth muscle cell remnants in the arteriolar media suggested this as one possible cell of origin. Frequent vessels showed medial or adventitial collagen deposition, even when the amount of amyloid was minimal or negligible. Thus relatively severe CAA can exist in the absence of overt endothelial injury, although related studies on this tissue indicate definite abnormalities of the blood-brain barrier. Conversely, destruction of smooth muscle cells and collagen deposition in vessel walls may be the cellular correlates of arteriolar weakening that can lead to CAA-related brain hemorrhage.

Progressive multifocal leukoencephalopathy in AIDS: a clinicopathologic study and review of the literature.

We reviewed the clinical, radiographic, and pathologic features of 15 patients with the acquired immune deficiency syndrome (AIDS) and progressive multifocal leukoencephalopathy (PML). Brain tissue from 10 autopsy and 6 biopsy specimens was studied using: in situ hybridization (ISH) for JC virus (JCV), immunohistochemistry for human immunodeficiency virus (HIV) p24 antigen, and electron microscopy. Thirteen patients presented with focal neurologic deficits, while 2 presented with a rapid decline in mental status. PML was commonly the initial opportunistic infection of AIDS and produced hemiparesis, dementia, dysarthria, cerebellar abnormalities, and seizures. Magnetic resonance imaging was more sensitive than computed tomography in detecting lesions, and often showed multifocal areas of PML. CD4+ T-cell counts were uniformly low (mean 84/mm3), except in 1 patient who improved on 3'-azido-3'-deoxythymidine (AZT). PML involved the cerebral hemispheres, brain stem, cerebellum, and cervical spinal cord. The distribution of brain involvement was consistent with hematogenous dissemination of the virus. In 2 brain specimens, multiple HIV-type giant cells were present within the regions involved by PML. When co-infection by HIV and papovavirus was present, PML dominated the pathological picture. ISH for JCV showed virus in the nuclei of oligodendrocytes and astrocytes. Occasionally there was staining for JCV in the cytoplasm of glial cells and in the neuropil, the latter possibly a correlate of papovavirus spread between myelin sheaths, as seen by electron microscopy. ISH demonstrated more extensive foci of PML than did routine light microscopy.

An assessment of the proliferative potential of 'balloon cells' in focal cortical resections performed for childhood epilepsy.

Cerebral cortical dysplasia is an uncommon pathological substrate of severe intractable childhood epilepsy, sometimes treated by hemispherectomy. Neuropathological findings include abnormal gyrus formation, loss of cortical lamination, unusual giant neurons and 'balloon cells' of indeterminate histogenesis similar in appearance to neoplastic gemistocytic astrocytes. In order to investigate the proliferative potential of 'balloon cells', we used Crocker's silver impregnation technique to demonstrate nucleolar organizer regions (AgNORs) involved in cellular proliferation, together with immunohistochemical evaluation of proliferating cell nuclear antigen (PCNA) expression. Balloon cells (5.56 +/- 0.24) had significantly (P < 0.001) greater AgNOR numbers than reactive astrocytes (3.89 +/- 0.15), neurons (2.30 +/- 0.13) or giant neurons (4.26 +/- 0.20). However, when corrected for nuclear size, results showed that 'balloon cells' (0.093 +/- 0.006) had significantly (P < 0.001) fewer AgNORs/square micrometre of nuclear area than reactive astrocytes (0.225 +/- 0.016) and had significantly (P < 0.001) more AgNORs/square micrometre of nuclear area than normal (0.048 +/- 0.003) or giant neurons (0.054 +/- 0.003). On the assumption that astrocytes are typical interphase cells and that normal neurons are post-mitotic, the results suggest that 'balloon cells' are unlikely to be undergoing proliferative activity and, when adjusted for nuclear size, the number of AgNORs/unit of nuclear area is more reflective of cellular ploidy than of proliferative activity in non-neoplastic neural tissues. The virtual absence of PCNA expression by 'balloon cell' nuclei supports such an interpretation of the AgNOR results.

Morphological substrates of infantile spasms: studies based on surgically resected cerebral tissue.

Extensive surgical resections of neocortical cerebral tissue (including hemispherectomies) from 13 infants and children with infantile spasms showed that 12 of 13 specimens contained either malformative and dysplastic lesions of the cortex and white matter (sometimes with associated hamartomatous proliferation of globular cells), or destructive lesions possibly acquired as a result of anoxic-ischemic injury, or a combination of the two. In brain tissue from 4 patients, coarse neuronal cytoplasmic fibrils resembling neurofibrillary tangles were seen in areas of dysplastic brain on silver-stained (Bielschowsky technique) sections. Immunohistochemical (immunoperoxidase) study of cortical lesions containing globular cells employing primary antibodies to glial fibrillary acidic protein and synaptophysin as markers of astrocytic and neuronal differentiation, respectively, revealed that many cells showed astrocytic and/or neuronal features, suggesting the local proliferation of primitive or multipotential neuroectodermal cells as one substrate for this seizure disorder. Morphological abnormalities of a severe degree and wide extent in the resected tissue (e.g., in one patient with hemimegalencephaly) often showed features to suggest that they may represent variants of tuberous sclerosis. These most likely result from abnormal movement and/or local proliferation of neuroectodermal precursors that have migrated from the germinal matrix to the cortical mantle. Cellular, molecular and neurophysiological study of these abnormalities is likely to yield information about basic molecular mechanisms of brain malformation and injury important in the pathogenesis of infantile spasms and other forms of focal or generalized epilepsy.

Neuropathologic findings in cortical resections (including hemispherectomies) performed for the treatment of intractable childhood epilepsy.

Despite the use of hemispherectomy in the treatment of medically refractory seizures since the early 1950's, few studies published have documented neuropathologic findings in the resected specimens. This report describes the neuropathologic findings in 38 children who underwent either hemispherectomy or multilobar cortical resection as treatment for medically intractable epilepsy between 1986 and 1990. Examination of the resected specimens revealed a variety of abnormalities which fell into four broad categories. Malformations or hamartomatous lesions were the dominant finding in 15 patients, whereas encephalomalacic lesions were the most prominent abnormality in 16; chronic pathogen-free encephalitits (Rasmussen's encephalitis) was present in 3 and an additional 3 children had Sturge-Weber-Dimitri syndrome. There were no gross or microscopic abnormalities in 1 patient. This report provides the first comprehensive description of the pathologic findings in a series of children with refractory epilepsy of varying types treated by hemispherectomy-multilobar resection.

Neuropathologic findings in surgically treated hemimegalencephaly: immunohistochemical, morphometric, and ultrastructural study.

Tissues from three cases of hemimegalencephaly (HME) causing intractable seizures treated by cortical resection were studied using immunohistochemical, ultrastructural, and morphometric techniques. Severe cortical dysplasia was seen in all cases and included lesions best characterized as hemilissencephaly and polymicrogyria. Blurring of the cortex-white matter junction, the presence of large neuronal heterotopias, and neuronal cytomegaly were frequent observations. Immunohistochemical analysis demonstrated cellular colocalization of astrocytic markers glial fibrillary acidic protein and vimentin in one case of hemilissencephaly. Morphometric data showed significant increases over controls in neuronal profile area in all cases of HME. Neuronal cell density was increased significantly above controls in one of the cases. The study shows that HME results from severe cortical dysplasia which may be caused by multiple insults, manifest in one of several ways, and reflects abnormal or altered signals that regulate cortical morphogenesis.

Cerebral hemorrhage with biopsy-proved amyloid angiopathy.

Clinical, radiological, and immunohistochemical findings in brain biopsy specimens from six patients with cerebral amyloid angiopathy-associated intracerebral hemorrhage were reviewed. Acute clinical presentations included headache, nausea and vomiting, loss of consciousness, and focal neurological deficits such as hemiplegia and blindness. Transient ischemic attacks experienced by one patient and referable to one hemisphere did not indicate impending hemorrhage in that region. Computed tomographic scans revealed acute, irregular, superficial, lobar hemorrhage with occasional ring enhancement. Immunohistochemical studies were performed on biopsy specimens using primary antibodies against portions of the Alzheimer A4 (beta-) peptide or gamma-trace peptide (the vascular amyloid protein in patients with hereditary cerebral hemorrhage with amyloidosis-Icelandic type). In all patients, anti-A4 and anti-gamma-trace labeled cerebral microvessels. Immunoreactive senile plaques were few compared with the numbers of stained microvessels. Reactive astrocytes in some patients were labeled by both antiserum samples, suggesting uptake or production of these proteins by the astrocytes. This study demonstrates the heterogeneous clinical and radiological features of cerebral amyloid angiopathy-related brain hemorrhage and the value of anti-A4 and anti-gamma-trace immunohistochemical study of biopsy material from patients with suspected cerebral amyloid angiopathy-related intraparenchymal bleeding.

Immunoreactive A4 and gamma-trace peptide colocalization in amyloidotic arteriolar lesions in brains of patients with Alzheimer's disease.

Cerebral amyloid angiopathy (CAA) defines a biochemically heterogeneous entity that manifests as effacement of cerebral microvessel walls by a fibrillar material with characteristic tinctorial properties. In biochemical terms, the amyloid that infiltrates blood vessels in CAA is composed of the A4 or beta peptide of Alzheimer's disease (AD), a molecule related to gamma trace or cystatin C (seen in patients with hereditary cerebral hemorrhage with amyloidosis in Iceland, HCHWA-I), or the PrP characteristic of spongiform encephalopathy and scrapie. Using antibodies to synthetic peptides representing portions of the 4.2-kd Alzheimer A4 peptide and the gamma-trace peptide, we immunostained sections of brain from patients with AD, senile dementia of Alzheimer's type, and CAA with associated leukoencephalopathy. Immunohistochemical studies demonstrated colocalization of the A4 and gamma-trace peptides within arteriolar walls, but only rarely in A4 amyloidotic capillaries or senile plaque cores of amyloid. When gamma-tracelike reactivity was noted in capillary walls, it was sometimes noted within the cytoplasm of pericytes. Immunostaining was always more intense when the anti-A4 antibody was used as the primary antibody. Gamma-trace immunostaining was more prominent on the adventitial component of arteriolar walls, whereas A4 staining was usually seen more diffusely throughout the blood vessel wall, especially in the media. Rarely individual pericytelike cells showed prominent gamma-trace immunoreactivity. These findings suggest that A4 and gamma-tracelike molecules may colocalize within arteriolar walls within the brains of patients with AD, and highlight the fact that CAA identified with AD and HCHWA-I are not as biochemically distinct as was assumed previously. Furthermore these findings suggest that other peptidases or protease inhibitors may be found within amyloidotic microvessel walls and may contribute to senile brain change and CAA-related strokes, including hemorrhage and encephalomalacia.

Immunohistochemical study of cerebral amyloid angiopathy. III. Widespread Alzheimer A4 peptide in cerebral microvessel walls colocalizes with gamma trace in patients with leukoencephalopathy.

Brain tissue from 11 patients with cerebral amyloid angiopathy, changes of Alzheimer's disease, and variable degrees of subcortical leukoencephalopathy was examined by immunohistochemical methods, using primary antibodies to peptide segments representing portions of the Alzheimer A4 (beta-) peptide or gamma-trace peptide (seen most commonly in Icelandic patients with cerebral hemorrhage (hereditary cerebral hemorrhage with amyloidosis [HCHWA-I]). Variable A4 immunostaining was seen within cortical (and rarely white matter) parenchyma in the form of senile plaques (with or without central cores), and within capillary and arteriolar walls. Within individual patients, A4 deposits were often primarily parenchymal or vascular, and when they were vascular they tended to be more prominent in arteriolar than in capillary wall segments. Perivascular A4 deposits were often detected around strongly immunoreactive microvessels. Gamma-trace immunoreactivity was noted in many A4-positive microvessel walls, but staining was always less intense than with the anti-A4 antibody. We conclude that patients with severe cerebral amyloid angiopathy may show wide variation in the severity and topography of A4 deposits within brain parenchyma. A4 may colocalize with gamma-trace peptide, suggesting that A4 and gamma-trace forms of cerebral amyloid angiopathy may not be as biochemically distinctive as has been suggested. Other proteases or protease inhibitors may contribute to the pathogenesis of cerebral amyloid angiopathy or cerebral amyloid angiopathy-related stroke syndromes.

Immunohistochemical study of cerebral amyloid angiopathy. II. Enhancement of immunostaining using formic acid pretreatment of tissue sections.

Cerebral amyloid angiopathy (CAA) is a biochemically heterogeneous entity most commonly associated with stroke syndromes, Alzheimer's disease (AD), Down's syndrome, and miscellaneous neurologic conditions. The authors have applied and extended (using formic acid pretreatment of histologic sections) an immunocytochemical technique that used antibody to a synthetic 28-amino acid peptide representing a segment of the AD amyloid precursor, to study CAA and related parenchymal amyloid deposits in brain tissues originally derived from: 1) patients with CAA with or without typical clinicopathologic features of AD, cerebral hemorrhage, and infarcts; 2) a young boy with angiocentric brain amyloid; 3) patients with familial (Icelandic, Dutch) forms of cerebral hemorrhage caused by CAA; and 4) Japanese patients with nonfamilial CAA-related brain hemorrhage, sometimes associated with histopathology characteristic of AD. Formic acid pretreatment of sections resulted in markedly enhanced staining of senile plaque core and microvascular, especially capillary, amyloid, and some apparent staining of the neuritic component of senile plaques. Perivascular halos of immunoreactive material were observed frequently. Neurofibrillary tangles were not immunolabeled, nor were blood vessels or any parenchymal components within cerebral white matter. CAA in Japanese patients with nonfamilial encephalic hemorrhages appeared immunocytochemically identical to AD-related CAA. Arterioles in brains that had severe CAA frequently showed significant stenosis of their lumina by nonamyloid hyaline or cellular material.