Neuropathologic correlates of leuko-araiosis

Correlations of leuko-araiosis with cerebral atrophy and perfusion in elderly normal subjects and demented patients

CT images of leuko-araiosis in brain slices were quantified according to volumes of reduced Hounsfield units in frontal periventricular white matter in groups of elderly patients with multi-infarct dementia (MID, n = 23) and dementia of the Alzheimer type (DAT, n = 16). Volumes of leuko-araiosis, estimates of atrophic cerebral tissue, and local cerebral perfusion utilising inhalation of xenon gas as the indicator were correlated on the same CT slices. Ratios of frontal leuko-araiosis to total brain tissue volume were similar for patients with MID and DAT (mean 5.7 (SD 2.1)% v 6.5 (3.2%)), and both were significantly greater than ratios in elderly normal volunteers (3.1(1.3)%, 0 < 0.001). Cerebral atrophy (measured as the ratio of volumes of cerebrospinal fluid to total brain area) for DAT patients was 17.0 (6.7)%, which was greater than for MID patients (12.5 (5.4)%; p < 0.05) and both types of patients showed more cerebral atrophy than did age matched, elderly normal subjects. Cerebral perfusion was decreased in all regions measured in patients with MID and DAT compared with elderly normal subjects. Multi variate regression analyses correlated frontal leuko-araiosis with reductions of local cerebral blood flow in subcortical grey matter (p < 0.025) in patients with vascular dementia but not in those with DAT. These quantitative measures implicate decreased perfusion due to atherosclerosis in territories supplied by the deep penetrating cerebral arteries in the pathogenesis of leuko-araiosis in patients with vascular dementia, but suggest a different pathogenesis for leuko-araiosis in Alzheimer's disease.

Leukoaraiosis in relation to prognosis for patients with lacunar infarction

BACKGROUND AND PURPOSE

Close relations between leukoaraiosis detected by computed tomography or magnetic resonance imaging and stroke, particularly lacunar infarction, have been reported. We studied whether leukoaraiosis is related to long-term prognosis for patients with lacunar infarction.

METHODS

We examined monthly 215 patients with lacunar infarction after their first stroke. They comprised 95 patients with leukoaraiosis disclosed by computed tomography on admission (58 men and 37 women; mean age, 71.3 +/- 9.0 years) and 120 patients without leukoaraiosis (81 men and 39 women; mean age, 65.5 +/- 8.9 years). These patients had no previous history of either stroke or obvious dementia before their index stroke. We compared the prognosis with and without leukoaraiosis based on analysis of recurrent stroke, survival, and the prevalence of dementia and rate of dependence in activities of daily living.

RESULTS

Life table analysis revealed that the recurrent stroke rate was significantly higher in the patients with leukoaraiosis than in those without it (p = 0.004). The prevalence of dementia and rate of dependence in activities of daily living both 1 month after the index stroke and at the end of the follow-up period were significantly higher in the patients with leukoaraiosis (all parameters, P less than 0.001). Their survival rate was significantly lower than in those not suffering from leukoaraiosis (p = 0.012). Significant differences in these comparisons were also observed after matching for age and sex.

CONCLUSIONS

The presence of leukoaraiosis as identified by computed tomography indicates a poor prognosis for patients with lacunar infarction.

Serum autoantibodies in patients with Alzheimer's disease and vascular dementia and in nondemented control subjects

BACKGROUND AND PURPOSE

In this study we sought to evaluate the clinical significance of serum autoantibodies to dementing processes.

METHODS

We assessed 40 age-matched subjects: 10 patients with probable Alzheimer's disease, 10 with possible Alzheimer's disease with cerebrovascular disease, 10 with vascular dementia, and 10 nondemented control subjects. Serum from each subject was tested for the presence of antithyroglobulin antibody, thyroid antimicrosomal antibody, gastric anti-parietal cell antibody, anti-smooth muscle antibody, antinuclear antibody, rheumatoid factor, antineuronal antibody, and anticardiolipin antibody. In addition, we investigated the sera of these patients for the presence of an antivascular antibody directed against the vascular basement membrane proteoglycan antigen and for circulating immune complexes.

RESULTS

Autoantibodies were present in 100% of the patients with possible Alzheimer's disease with cerebrovascular disease, 80% of those with vascular dementia, 40% of those with probable Alzheimer's disease, and 30% of the nondemented control subjects. The highest number of autoantibodies was observed in patients with vascular dementia and possible Alzheimer's disease with cerebrovascular disease. Antinuclear antibody was present in 60% of vascular dementia patients and antineuronal antibody in 50% of these patients. However, no individual autoantibody could differentiate Alzheimer's disease from cerebrovascular disorders. Immune complexes were detected in the serum of 20-30% of each patient group. Neither the patient nor the control sera was found to contain antiendothelial antibody.

CONCLUSIONS

Despite the relatively small number of individuals examined in each category, the elevated number of autoantibodies associated with possible Alzheimer's disease with cerebrovascular disease and vascular dementia indicates a possible link between the presence of autoantibodies and cerebrovascular disorders in dementia.

White matter lesions in the elderly

The advent of neuroimaging has brought medical attention to the frequency of unsuspected white matter lesions in the brains of elderly people. In 1987 Hachinski suggested the term "leuko-araiosis" to identify such white matter abnormalities detected by computed tomography and magnetic resonance imaging to emphasize that their etiology and clinical relevance require clarification. Since then, leuko-araiosis has been recognized among approximately ten percent of apparently normal, elderly people over age sixty-five. The severity and frequency of leuko-araiosis increases with advancing age, risk factors for stroke, history of strokes particularly of the lacunar type and dementia of both the vascular and Alzheimer type. Current concepts concerning the pathogenesis and neurological concomitants of leuko-araiosis are reviewed. The etiology of leuko-araiosis may be heterogeneous but is most likely ischemic in nature. However, as white matter lesions progress among the elderly they are likely to become associated with cognitive impairments and motor dyspraxias presumably resulting from cortico-subcortical disconnections, particularly involving the frontal cortex and basal ganglia and may themselves be considered a radiological "risk factor" or precursor for dementia.

Vascular dementia: neuropathologic alterations and metabolic brain changes

After reviewing the concepts of dementia, in general, and vascular dementia, in particular, this review discusses potential future approaches that may contribute to an improved definition of the clinical syndrome and the neuropathological features of vascular dementia. Specific brain alterations in high-energy phosphate compounds, as measured by nuclear magnetic resonance, may contribute to the separation between dementias with neurodegenerative diseases and those with ischemic (vascular or hemodynamic) disorders.

Cranial computed tomographic observations in multi-infarct dementia. A controlled study

BACKGROUND AND PURPOSE

We compared cranial computed tomography findings among 58 multi-infarct dementia index cases and 74 multi-infarct control subjects without cognitive impairment to identify potential determinants of multi-infarct dementia.

METHODS

The cranial computed tomography records of acute ischemic stroke patients with a history of multiple cerebral infarcts were compared to determine the number, location, and size of cerebral infarcts; the pattern of infarction; brain volume loss; and the degree of white matter lucency, sulcal enlargement, and ventricular enlargement. Multi-infarct patients were divided into two groups: 1) index cases were defined as those with multi-infarct dementia as defined by the Diagnostic and Statistical Manual of Mental Disorders, edition 3 (DSM-III) criteria; and 2) control subjects were defined as those multi-infarct patients without dementia or multi-infarct dementia according to DSM-III criteria.

RESULTS

Overall, multi-infarct index cases had more cerebral infarcts, more cortical and subcortical left hemisphere infarcts, higher mean ventricular volume to brain volume ratio, more extensive enlargement of the body of the lateral ventricles and cortical sulci, and a higher prevalence of white matter lucencies. Among multi-infarct cases and control subjects the most frequent site of infarction was the subcortical region, and the most frequent pattern of infarction was lacunar. Stepwise logistic regression analysis examined cranial computed tomography as well as other factors and showed that level of education, stroke severity, left cortical infarction, and diffuse enlargement of the left lateral ventricle were the best overall predictors of multi-infarct dementia.

CONCLUSIONS

Level of education, stroke severity, and left hemisphere infarction may be predictors of multi-infarct dementia.

Patterns of cerebral hypoperfusion compared among demented and nondemented patients with stroke

BACKGROUND AND PURPOSES

No reports are available that compare local cerebral perfusion among groups of patients suffering from multiple cerebral infarctions with and without cognitive impairments. The present study was designed to correlate changes in regional cerebral perfusion that may lead to dementia among patients with multiple cerebral infarctions by comparing measurements of local cerebral blood flow.

METHODS

Local perfusion was measured using xenon-contrasted computed tomographic scanning among two groups of patients who had suffered from multiple cerebral infarctions: Group D (n = 12) were demented and had severe cognitive impairments, and group I (n = 11) were cognitively intact. Results were compared with similar measurements among neurologically and cognitively normal, age-matched volunteers (group N, n = 16).

RESULTS

Mean local perfusion values were reduced among both groups with cerebral infarctions but to a more marked degree in group D (p less than 0.05). Perfusion of cerebral white matter was diffusely and severely reduced in group D (p less than 0.05) but was mildly reduced only in frontal and capsular white matter in group I (p less than 0.05). Perfusion of cerebral cortex was reduced in frontal (p less than 0.01) and temporal (p less than 0.01) regions among both groups but to a significantly greater degree in group D subjects (frontal, p less than 0.05; temporal, p less than 0.01), who also showed hypoperfusion of the occipital cortex (p less than 0.05), apparently because of underlying leukoaraiosis and cortical disconnections. Perfusion of the basal ganglia was reduced to the same degree among both groups of stroke patients (p less than 0.01).

CONCLUSIONS

Leukoaraiosis with white matter hypoperfusion appears to be an important determinant for cognitive impairments among patients with multiple cerebral infarctions.

beta-Amyloid precursor protein of Alzheimer's disease in cultured bovine oligodendrocytes

The production of beta-amyloid precursor protein (beta APP) in cultured oligodendrocytes isolated from adult bovine brains was examined by immunohistochemistry and immunoblotting. Immunostaining of oligodendrocytes with antibodies specific for the carboxy terminus of beta APP demonstrated positive immunoreactivity of oligodendroglial cytoplasm. Immunoblot analysis of cellular extracts detected two distinct bands with estimated molecular weight of 118 and 105 kDa. The amount of these beta APP subspecies increased considerably in response to their attachment to the poly-L-lysine substratum.

Clinical heterogeneity of probable Alzheimer's disease

When the symptomatology in probable Alzheimer's disease (AD) was studied, two subgroups emerged: one with predominant cortical symptoms of parietal type (AD type I) and another with general cognitive symptoms but absence of or only mild cortical symptoms (AD type II). In AD type I, the age at onset was significantly lower, confusional symptoms and leukoariosis on computerized tomographic scan were less frequent, and the ganglioside GM1 concentration in cerebrospinal fluid was significantly higher than in AD type II. Although the significance of changes in cerebrospinal fluid gangliosides has not been fully elucidated, it is possible that the increase in cerebrospinal fluid GM1 reflects a more severe degeneration of neurons and synapses in AD type I than in AD type II. The relation between symptomatology and leukoariosis suggests that leukoariosis has clinical significance in AD patients. The total results suggest heterogeneity of probable AD. AD type I appears to constitute a classic AD subgroup with memory disturbances and marked cortical symptoms of parietal type, while age-related changes, vascular changes, and leukoariosis may be responsible for the more generalized symptomatology in AD type II.

Leuko-araiosis and cerebral hypoperfusion compared in elderly normals and Alzheimer's dementia

OBJECTIVE

To elucidate the pathogenesis of leuko-araiosis in patients with Alzheimer's disease by utilizing CT densitometry of the brain and measurements of local perfusion in order to quantify the extent of leuko-araiosis and local hypoperfusion compared with similar measurements made among age-matched normal volunteers.

DESIGN

Cross-sectional case-control study.

SETTING

Out-patient visits to a specialized laboratory located in a large hospital facility.

PATIENTS

Eighteen elderly patients with probable dementia of Alzheimer type (DAT, aged 71.8 +/- 5.1 years) and 17 neurologically and cognitively normal, age-matched volunteers (aged 68.2 +/- 9.6 years) were admitted to the study according to established criteria.

INTERVENTION

None

MAIN OUTCOME MEASURES

Cerebral blood flow (mL/100 g brain/min) estimated by the xenon inhalation CT-CBF method correlated with volume percentage ratio (%) measured by CT densitometry for leuko-araiosis, compared to normal white and gray matter.

RESULTS

Perfusion values for frontal and occipital white matter as well as frontal, parietal, temporal, and occipital cortex were all decreased in DAT patients. Ratios for leuko-araiosis to total brain tissue volumes were greater among patients with DAT compared with age-matched normal volunteers. White matter perfusion in zones of leuko-araiosis was decreased to a similar degree in both DAT and elderly normal volunteers.

CONCLUSIONS

Perfusion is reduced to the same degree in regions of leuko-araiosis in elderly normals as in DAT patients, but the extent of leuko-araiosis is greater among DAT patients and presumably contributes to cognitive impairments.

Clinical correlates of high signal lesions on magnetic resonance imaging in Alzheimer's disease

The pathophysiology and clinical significance of high signal lesions, visualized on magnetic resonance imaging (MRI) in patients with Alzheimer's disease (AD), remain controversial. Since they are known to correlate with vascular disease and vascular risk factors, we reviewed the clinical correlates of periventricular high signal (PVH) and subcortical white matter lesions (WML) in a sample of 106 patients with probable AD, excluding persons with treated vascular risk factors or symptomatic cerebrovascular and cardiovascular disease. Grade 2 PVH were seen in 26 (25%) and scattered WML were identified in 29 (18%). PHV were associated with advancing age and gait disturbance. WML were associated with gait disturbance and incontinence. Neither radiologic finding was related to dementia severity. The findings suggest that these lesions are common in patients with AD even when those with evidence of cerebrovascular disease are excluded; their presence, therefore, should not preclude a diagnosis of AD. Additionally, the data suggest that HSL on MRI may be one of many risk factors associated with functional disability in persons with probable AD.

Alzheimer's disease

Alzheimer's disease is one of the most severe and most common chronic diseases of older persons. Because occurrence of the disease is strongly related to age, its public health impact is likely to continue to increase as the population ages. As with many other diseases, a diagnosis of Alzheimer's disease is made through a combination of clinical history, physical, and neurologic examination, and laboratory evaluation. Because the dominant feature of this disease is its effect on cognition, its diagnosis requires careful evaluation of cognitive function usually with formal neuropsychological performance testing. Clinical evaluation of persons for Alzheimer's disease has four objectives: (1) to determine as accurately as possible if the person has dementia; (2) if dementia is present, to determine whether its presentation and course are consistent with a diagnosis of Alzheimer's disease; (3) to assess evidence for any alternate diagnoses, especially if the presentation and course are atypical for Alzheimer's disease; and (4) to evaluate evidence of other, coexisting, diseases that may contribute to the dementia, with strong emphasis on conditions that might respond to treatment. There is no reliable antemortem diagnostic test for Alzheimer's disease; the main purpose of laboratory testing is to identify other conditions that might cause or exacerbate dementia. Pathologically, Alzheimer's disease is characterized by the presence of two lesions on microscopic examination of the brain: neuritic plaques and neurofibrillary tangles. Both lesions can be seen in the brains of older persons without dementia. However, they are found in greater numbers in the neocortex and hippocampus with Alzheimer's disease. Caring for patients with Alzheimer's disease is demanding and requires compassion and skills that go beyond the choices among sophisticated and effective therapies that characterize much of modern medical practice. The current lack of effective pharmacotherapy for cognitive dysfunction in Alzheimer's disease should not obscure that there are many areas in which intervention can improve quality of life for both the patient and the caregiver. Achieving success in these areas typically requires that the physician work effectively with providers of many other medical and nonmedical services. Community resources, advocacy, behavior management, and experimental therapies and procedures, should be discussed with the family of each patient. In addition, persons with mild disease should be promptly informed of their diagnosis in order to obtain their wishes regarding life prolonging measures and extended care options.

Hereditary cerebral hemorrhage with amyloidosis--Dutch type: a congophilic angiopathy. An overview

Hereditary cerebral hemorrhage with amyloidosis--Dutch type (HCHWA-D) is characterized by recurrent cerebral hemorrhages and dementia at a relatively young age. The symptoms are caused by extensive deposition of amyloid in cerebral arterioles and leptomeningeal arteries. A point-mutation in the beta-protein precursor gene on chromosome 21 is the underlying cause of the disease. This paper summarizes the clinical, radiologic, pathologic, and genetic features of this disease, with special attention to the relation between HCHWA-D and Alzheimer's disease, which is also characterized by beta-protein deposition.

Amyloid beta protein deposition in brains from elderly subjects with leukoaraiosis

We studied immunocytochemically with 2 amyloid beta protein (ABP) antisera brains from 5 non-demented elderly subjects with evidence of diffuse periventricular white matter hypodensity on computed tomography. In periventricular white matter of all brains we found ABP reactive deposits arranged around small vessels walls. Furthermore ABP reactive deposits, identical to those currently called diffuse plaques, were detected in neocortex in amount proportional to that of white matter deposits. We suggest that ABP microangiopathy and parenchymal deposition is responsible of white matter rarefaction in a subset of cases with a diffuse hypodensity on CT scan which has been called leukoaraiosis.

Hereditary cerebral hemorrhage with amyloidosis--Dutch type: its importance for Alzheimer research

Alzheimer's disease is now commonly regarded as a form of 'amyloid encephalopathy'. Amyloid deposits in the cerebral blood vessels and parenchyma consist mainly of a unique protein called amyloid beta protein (A beta P), which has a molecular weight of 4 kDa and is 42 amino acids long. These deposits are thought to be of pathogenetic importance in Alzheimer's disease. Recently, therefore, attention has been focused on the process of turnover of the precursor of A beta P to amyloid fibrils, and the deposition and persistence of A beta P in this disease. The study of several other diseases with cerebral A beta P deposition can be informative in this respect, because they allow the comparison of different pathogenetic mechanisms that lead to this type of deposition. One of these diseases is hereditary cerebral hemorrhage with amyloidosis- Dutch type (HCHWA-D), which is the subject of this review.

A phase II study of days 1 and 8 cisplatin and recombinant alpha-2B interferon in advanced non-small cell lung cancer

Preclinical data from studies of human lung cancer xenografts suggest that the cytotoxic effects of cisplatin are enhanced by alpha-interferon. To verify the above observations, the authors initiated a Phase II trial in advanced non-small cell lung cancer (NSCLC). Cisplatin was given at 100 mg/m2 during a 28-day cycle in a divided day 1 and day 8 schedule. Starting on day 1, alpha-2B interferon was administered intramuscularly at a dose of 5 million units three times a week continuously for a minimum of 2 months. Between January 1989 and September 1989, 30 patients were evaluated for response and toxicity. According to the staging system proposed by Mountain, 20 patients had Stage IV disease, 7 had Stage IIIB disease, and 3 had Stage IIIA disease. Expression of neuron-specific enolase (NSE) and Leu-7 was immunohistochemically investigated to evaluate possible relationship to treatment response. The response rate was 13.3% (95% confidence interval [CI]: 1.2% to 25%). The four responders showed positivity for NSE, and two of them were positive for Leu-7. An average of three cycles was given. The mean dose intensity administered was 83% of the projected dose for cisplatin and 92% of the projected dose for alpha-2B interferon. A standard scale was used to assess interferon toxicity. Hematologic, renal, and systemic side effects were not significant. In advanced NSCLC the addition of alpha-2B interferon did not increase the cisplatin-induced response rate. Further studies should be performed to determine the real value of chemotherapy response in tumors showing positive immunoreactivity for neural markers such as NSE and Leu-7.

Leukoaraiosis correlates with cerebral hypoperfusion in vascular dementia

Leukoaraiosis quantified by computerized densitometric measurements of reduced Hounsfield numbers was correlated with local cerebral blood flow on the same computed tomographic images of 35 patients with multi-infarct dementia and 16 age-matched elderly normal volunteers. The ratio for area of frontal leukoaraiosis to total area of parenchyma among the patients was significantly greater than that among the normal volunteers (5.8 +/- 2.3% compared with 3.1 +/- 1.3%, p less than 0.001). Severity of leukoaraiosis around the frontal horns of the lateral ventricles correlated significantly with severity of leukoaraiosis of the centrum semiovale adjacent to the bodies of the lateral ventricles. Cerebral blood flow values for all representative cerebral regions except the parietal white matter were reduced among the patients compared with the normal volunteers. Multivariate regression analysis revealed that reduced cerebral perfusion in the putamen and thalamus correlated significantly with the severity of leukoaraiosis. Cerebral hypoperfusion in territories supplied by deep penetrating arteries may contribute to the pathogenesis of leukoaraiosis.

Could Wallerian degeneration contribute to "leuko-araiosis" in subjects free of any vascular disorder?

To determine the possible role of Wallerian degeneration secondary to the grey matter neuronal loss in the pathogenesis of "leuko-araiosis", computerised tomography (CT) of the brain was studied in 98 normotensive and non diabetic subjects free of cardiac diseases: 32 with Alzheimer's disease, 36 with Parkinson's disease, eight with progressive supranuclear palsy, and 22 controls. In Alzheimer's disease, leuko-araiosis scores were greater than in control subjects. Leuko-araiosis was more prominent in anterior periventricular areas in Parkinson's disease and progressive supranuclear palsy, and in posterior periventricular areas in Alzheimer's disease. In two patients with Alzheimer's disease and leuko-araiosis, necropsy revealed diffuse white matter pallor, mild fibrillary astrocytosis, and in one patient limited hyaline thickening of small white matter vessels, without any infarction or hypertensive change. Changes were more severe in white matter close to cortical areas with a great density of neurofibrillary tangles. Leuko-araiosis was more severe or more widespread in Alzheimer's disease than in Parkinson's disease, progressive supranuclear palsy and normal ageing. Differences in the location of leuko-araiosis between the four groups might be due to differences in the location of the grey matter disorder and Wallerian degeneration rather than amyloid in Alzheimer's disease, Parkinson's disease, progressive supranuclear palsy and normal ageing. Wallerian degeneration might be another cause of leuko-araiosis in neuro-degenerative disorders beside previously reported extra-cerebral predisposing factors and amyloid angiopathy.

Leukoaraiosis, intracerebral hemorrhage, and arterial hypertension

To investigate whether the observed association of leukoaraiosis with intracerebral hemorrhage is direct or mediated by risk factors, we compared 116 patients with intracerebral hemorrhage confirmed by computed tomography and 155 controls without intracerebral hemorrhage, evaluating the prevalence of leukoaraiosis and vascular risk factors. Leukoaraiosis was observed in 21 (18%) of the 116 patients and in 12 (8%) of the 155 controls (p less than 0.01). Only two (6%) of the 31 patients with lobar hemorrhage had leukoaraiosis on computed tomograms, compared with 17 (24%) of the 71 patients with basal ganglionic hemorrhage (p less than 0.05). Leukoaraiosis was significantly correlated with intracerebral hemorrhage after controlling for age and sex by using multiple logistic regression analysis, while the correlation disappeared after controlling for hypertension. Our results indicate that leukoaraiosis is not an independent risk factor for intracerebral hemorrhage.