Cholesterol and tau protein--findings in Alzheimer's and Niemann Pick C's disease.

Niemann Pick C (NPC), a fatal autosomal-recessive neurovisceral lipid storage disorder, is a juvenile dementia with massive nerve-cell loss and cytoskeletal abnormalities in cerebral neurons. These abnormalities consist of tangles of tau protein, which is otherwise highly soluble and usually stabilizes the microtubules. Immunologically and ultrastructurally similar tangles are seen some decades later in patients with Alzheimer's disease (AD). There is evidence that tangle-bearing cells in both diseases show higher levels of free (i. e. filipin-positive) cholesterol than adjacent tangle-free nerve cells. The cholesterol accumulates either in a more diffuse way (mainly in AD) or in granule-like accumulations (mainly in NPC). In NPC, neuron cholesterol may originate from sources other than the alimentary tract. Experiments with a NPC mouse model revealed that even in pure neuron cultures, the NPC -/- neurons accumulate free cholesterol in contrast to NPC-wt littermates, suggesting that the cholesterol is either synthesized by the neurons or liberated from degenerated ones before being taken up by the endosomal/lysosomal pathway. The accumulation of free cholesterol in the somata of NPC neurons is associated with a decrease of cholesterol levels in myelin sheaths. In terms of tau protein, NPC -/- mice exhibit higher levels of AT8-positive tau, suggesting that the phosphorylation-dependent mAb AT8 has detected a tau-epitope in a state considered to represent early stages of tangle formation. Concomitantly to the increase in free intracellular cholesterol, the rate-limiting enzyme in cholesterol and isoprenoid biosynthesis, HMG-CoA reductase, was found to be significantly reduced. Experimental blockade of the enzyme's activity by application of the lipid-lowering drug lovastatin showed subcellular shifts in tau phosphorylation as monitored with mAbs AT8, 12E8 and others. In summary, the data showed interesting similarities between NPC and AD suggesting some pathological metabolic pathway in common.

Transneuronally altered dendritic processing of tangle-free neurons in Alzheimer's disease.

In Alzheimer's disease (AD), changes in dendritic morphology can be regarded as a result of an inherent disease-specific process associated with the formation of neurofibrillary tangles. Using three-dimensional morphometrical techniques and neuropatholologically staged tissue (Braak classification) of 32 cases, we demonstrate alterations in the dendritic length, branch order and number of segments of a tangle-free neuronal population in the AD-afflicted hippocampus, i.e. parvalbumin-containing cells of the fascia dentata. These alterations occurred primarily on the apical dendritic tree, the target of the entorhinal input. Mean of relative dendritic length, branch order and number of dendritic segments of apical dendrites decreased significantly, by 40-70% comparing stage V to stages 0 or I. In contrast, basal dendrites receiving no entorhinal input did not show significant changes. Entorhinal neurons projecting to the hippocampus are the first to be affected in AD and the first to die, resulting in hippocampal deafferentation. Therefore, this input-specific dendritic alteration of tangle-free neurons suggests that AD is confounded with a transneuronal component resulting from deafferentation. Experiments showed that deafferentation results in altered dendritic geometry causing an impaired signal integration. Thus, transneuronally altered dendritic signal integration might occur in neurons devoid of the major intraneuronal hallmark of AD, i.e. the neurofibrillary tangle.

Anorexia nervosa and sudden death in childhood: clinical data and results obtained from quantitative neurohistological investigations of cortical neurons.

A crude rate of mortality of 5.9% has been quoted for Anorexia nervosa (AN) in recent studies. There are different causes of death ranging from suicide to sudden death. Autopsy data are extremely rare about brain alterations in deceased AN patients. Reported in this study is a female patient, aged 13.5 years, who died of acute AN. Quantitative neurohistological investigation post mortem was performed on her brain. Results were compared with data obtained from a girl of the same age with no contributory neuropsychiatric findings. In the cortex of the anorexia case beside typical pyramidal neurons, a slim neuron type with one extremely long basal dendritic field was found to occur more frequently than normal. In the neurons of the AN case, the ramification pattern of single basal dendritic fields was found to be reduced and changes in the spine morphology, as well as reduction in spine density, were observed. However, a simultaneous lengthening of the terminal dendrites of higher order gave some evidence for repair mechanisms and neuronal plasticity. The AN-specific implications of these findings are discussed. The conclusion is that all AN deaths should be reported together with descriptions of causes and cerebral alterations.

Morphometrical investigations on lamina-V-pyramidal-neurons in the frontal cortex of a case with anorexia nervosa.

Pyramidal neurons in the motor cortex of a lethal case of anorexia nervosa were investigated by means of a computer-assisted three-dimensional quantitative neuronographic method. The differentiation level of GOLGI-impregnated lamina-V/VI-pyramidal-neurons was analyzed by comparison of parameters such as the number of basal dendritic fields, ramification degree, length of dendritic segments and spine density with data estimated in another case of corresponding gender and age. In the anorexia case, as well as typical pyramids, a slim neuron type with one extremely long basal dendritic field was found to occur more frequently. In all the neurons investigated, the ramification pattern of single basal dendritic fields was found to be reduced and changes in the spine morphology as well as a reduction in spine density were observed. However, a simultaneous lengthening of the terminal dendrites of higher order give some evidence for the coincidence of regressive process with repair mechanisms and neuronal plasticity.

[Quantitative studies in lamina V-pyramidal neurons of the frontal brain after infantile brain damage]. / Quantitative Untersuchungen an Lamina V-Pyramidenneuronen des Frontalhirns nach frühkindlicher Hirnschädigung.

Cortical pyramidal neurons (lamina V, Area 10) were investigated in brain autopsy material obtained from 8 patients with serious bodily and mental retardation, aged between 3 and 24 years. Quantitative neuromorphological estimations of the ramification degree, length and spine density of apical or basal single dendritic fields (SDF) of these neurons were carried out using the impregnation technique of GOLGI and a computer-assisted quantification method. The results were compared with related data found in the prefrontal cortex (Area 10 according to Brodmann) of patients in the same age without neuropathological or psychiatric disturbances. During the normal maturation period the development of dendritic length and spine density reflects the diminution of the relative excess of growth during the early postnatal phase. When comparing the dendritic length or spine density of a SDF in children with that of juvenile adolescents or young adults, the length is reduced by 40%, the spine density by 15%. In the brains of mentally retarded children we found the dendritic length reduced by 30% (apical) or 40% (basal), and a further elongation and ramification of the dendritic tree (especially nonramified terminal dendrites) in juvenile adolescents. However, the spine density showed a significant deficit of about 30% in children as well as in juvenile adolescents. This spine loss may be morphologically related to the symptoms of mental retardation. In these cases, the genetically controlled spine distribution pattern along the dendritic orders was not changed. The results obtained are discussed by taking into consideration data from animal experiments as well in view of the normal or disturbed neuronal development.

[Neurohistological study of the dendrites of lamina V-pyramidal neurons of the rat following recovery from postnatal malnutrition]. / Neurohistologische Untersuchungen an Dendritenspines von Lamina V-Pyramidenneuronen der Ratte nach Rehabilitation von frühpostnataler Mangelernährung.

By means of the GOLGI technique the influence of unspecific early postnatal undernourishment (from day 1 till day 20 of postnatal life followed by 40 days of recovery) on the spine morphology was investigated in the brain cortex of young adult animals, 60 days old. It was found that in experimental animals the three main spine types (thin spines, mushroom spines and stubby spines) had developed on apical lateral dendrites of cingulate pyramidal neurons, indicating the realization of the morphological characteristics of pyramidal neurons during starvation and recovery. However, in 60 days old control animals 65-70% of the spines belonged to the thin spine type, but in undernourished and rehabilitated animals the mushroom type is dominating and its percentage was found to have increased from 25-30% (controls) to 50% of all spines. Additionally, a significant enlargement of the stalked spines, especially of their synaptic end-knobs bearing spine heads was demonstrated in experimental animals. In undisturbed animals the short thin stem spine is considered to be necessary in a certain percentage to secure an optimum of resting activity in the neuron. The enhancement in the total spine number of 40-50% between day 20 (end of starvation) and day 60 (end of recovery), found earlier by us, taken together with the present results (increase in mushroom spines and spine head enlargement) point to a real new formation by division of previously enlarged mushroom spines as well as to transformations and shifts in the spine population during the recovery time. In the formation, development and maturation of the spines a change in their morphology from the filopodium-like type over the mushroom type and finally the thin stalked type may occur. Our results are discussed as being the expression of the neuronal plasticity persisting far into adulthood in order to enable the organism to react adaptive against changed living conditions.

[Neurohistologic studies of cortical pyramidal neurons in the rat following rehabilitation of early postnatal malnutrition]. / Neurohistologische Untersuchungen an kortikalen Pyramidenneuronen der Ratte nach Rehabilitation von frühpostnataler Mangelernährung.

The experimental animals were 60 days old rats which had been suffering from undernutrition during day 1 till day 20 of their early postnatal life. The recovery from the retardation in brain development induced by the experiment was investigated by quantitative light microscopical methods in GOLGI impregnated material. In pyramidal neurons of lamina III or V of the anterior cingulate cortex several neuronal parameters were estimated in a single dendritic field (EDF) indicative for the development of the dendritic tree and spine distribution of these neurons. The results demonstrate a sufficient recovery in those cases when the rehabilitation is beginning already within the period of intensive brain growth. The duration of this growth spurt is prolongated in the experimental animals. Therefore, after the starvation period the brain is supposed to have some potency for further neuronal differentiation, also beyond the 20th day of life. This fact is considered to be decisive for a full recovery. After the starvation period at day 20 the lamina V pyramidal neurons were found to have developed a significantly smaller dendritic tree (minus 15%) equipped with a strongly reduced spine number (minus 30%). After the recovery time of 40 days the control values were reached, moreover, the spine density in apical dendrites was enhanced in comparison to controls. Likewise, in the lamina III pyramidal neurons of experimental animals, the apical dendritic tree was shortened by 25-30%, the basal dendritic tree by 10% at the end of the undernutrition period. However, after recovery of 40 days the dendritic tree of these neurons developed a significant overshoot of 15-20% in comparison to controls. The spine number at basal dendrites was similar to controls, but at apical dendrites significantly higher. The differences in the recovery pattern of both neuron types are explained by the hypothesis that the lamina III pyramidal neurons are phylogenetically younger and, therefore, have a considerably longer postnatal differentiation phase. Thus, they show a stronger retardation in growth by the undernutrition. However, during rehabilitation and recovery they show a larger increment in growth and differentiation.

[Effect of nonspecific malnutrition on spine morphology of lamina V pyramidal cells of the cingulate area of juvenile and adult rats]. / Der Einfluss einer unspezifischen Mangelernährung auf die Spinemorphologie von Lamina V-Pyramidenzellen der Regio cingularis juveniler und erwachsener Ratten.

The spine morphology of LV--pyramidal neurons in the cingulate cortex was analyzed, using drawings of apical side dendrites without ramifications, by light microscopical analysis of 5300 times magnification in GOLGI-preparations of the brains of 11 and 60 days old control rats as well as of experimental animals reared under starvation conditions from day 1 till day 60 of their postnatal life. The spine density and the relative frequency of three different spine types (thin, mushroom and stubby shaped) was estimated in control and undernourished animals. Undernutrition resulted in a considerable deficit in the spine number of 25% in 11 days old animals, respectively, of 41% in 60 days old animals. Additionally, in 60 days old undernourished rats changes in the relative frequency of the three spine types was found. To the thin type belonged 46% (68% in controls) to the mushroom shaped form 37% (19% in controls) and to the stubby type 16% (13% in controls) of all visible spines. This pattern in 60 days old undernourished rats was very similar to the pattern of 11 days old control animals (thin 43%, mushroom 36%, stubby 22%). The evaluate the differentiation of the dendritic spines during ontogenesis as well as the disturbing influence of undernutrition on these processes, additional data of the spine morphology (neck length and head area) were collected. The spines of the 11 days old animals showed a larger head area (undernourished and controls) than the young adult ones. However, the thin spine type present in 60 days old undernourished rats exhibits morphological features (extremely long necks of about 2,5 micron in comparison to 1,6 micron in controls as well as very large heads) which appeared to be quite similar to the thin and long spine type observed by PURPURA (1975) in human fetal cortex and in cortex of patients with mental retardation. This super long thin spine type is considered to be a less ripe stage of the spine development. The relative high portion of mushroom and stubby shaped spines in undernourished and young animals points to the same assumption or to degenerative changes in the experimental animals.

[Correlation of neuronal parameters of cingulate lamina V and lamina III pyramidal neurons in the rat]. / Korrelation neuronaler Parameter von cingulären Lamina V- and Lamina III-Pyramidenneuronen der Ratte.

The data obtained by quantitative neuromorphological investigations of pyramidal cells from the cingulate cortex of 3 month old rats gave evidence for significant statistical correlation between different parameters of lamina III- as well as lamina V-pyramids. The spine-number counted in single apical dendritic fields (EDF) was highly positive correlated to the total apical spine-sum and the some correlation existed in the basal dendritic tree; i.e. the data obtained in a basal EDF were representative for the whole basal dendritic tree, respectively. In the fully developed pyramids the parameters of the apical dendritic tree were considered to be of stronger importance for the data collected from the whole dendritic tree of the neuron. However, in more primitive pyramids the parameters of the apical and basal dendritic tree were found to be of the same significance for the data of the whole neuron. The development of the apical dendritic tree when compared with the basal one gave never positive correlations in their sum parameters. Significant correlation was obtained between the length of the dendrites and the volumes of their distribution area. In fully developed regular pyramids the statistical analysis gave evidence for a higher importance of distal parts of the dendritic tree as representative for the sum parameters, in contrast to primitive pyramids with higher significance of the perikaryon-near parts. These primitive pyramids are quite abundant in the phylogenetically older mesoarchicortical and mesoneocortical parts of the cingular cortex.

[The influence of early postnatal undernourishment on the development of cortical neurons in the rat]. / Uber den Einfluss einer frühen postnatalen Mangelernährung auf die Reifung kortikaler Neurone bei der Ratte.

The influence of early postnatal undernutrition on growth and maturation processes in pyramidal and stellate neurons of the cingulate cortex was investigated quantitatively in Golgi-Kopsch impregnated sections of the rat brain from 11, 20, 35 and 60 days old control and experimental animals. The starvation experiment was performed by separation the offspring from their mother for hours daily during the first three weeks of postnatal life, continued up to the 60th day by feeding only 5 g pellets per day (which a normal demand of about 20 to 25 gram a day). Data of dendritic ramification, length and spine density were collected as parameters for neuronal development and maturation. In undernourished animals a retardation of the neuron maturation was found. The inhibiting effect of starvation was most pronounced during those periods of brain development showing the highest intensity of the maturation processes in controls: these periods are for lamina V pyramids the early postnatal phase, for Lamina III pyramids the early and late postnatal phase, for interneurons the late postnatal phase only. Thus, the pattern of damage reflects the heterochronicity of maturation of different neuron types. The lamina V pyramids with relative rapid postnatal development were less affected, however, their main spine maturation period covering the 11th upto the 20th day in controls was found to be postponed and the spine density reached finally was diminished. The lamina III pyramids were stronger affected by starvation due to their immature state in the beginning of the experiment and their prolonged maturation. These cells showed remarkable deficits in the spine maturation along the apical side and basal dendrites during the first 3 weeks of postnatal life, in the apical main dendrite up to the 60th day. The most striking effect of starvation occurred in interneurons which differentiate postnatally late and slowly. In controls more than 50 per cent of the dendritic spines appear later than on postnatal day 20. In experimentals the spine density was reduced by 40% already on day 20. Moreover, the deficit increased on day 60 to reach a level of about 60%. These results give evidence for a longlasting injury of the neuropil as morphological basis for mental dysfunction.

[Effect of sensory deprivation on the lamina V pyramidal neurons in the rat cingulate gyrus]. / Der Einfluss sensorischer Deprivation auf die Lamina-V-Pyramidenneurone des Gyrus cinguli der Ratte.

Three groups of Wistar-rats were reared in the dark during different periods in their postnatal life: the first group was reared in the dark starting from birth for a period of four weeks, the second one from birth up to nine weeks of age and the third one from the fifth up to the ninth week postnatal. Two groups of control animals were reared under normal laboratory conditions from birth up to four or else up to nine weeks of age. The brains were processed according to a modified Golgi-Kopsch method. In lamina-V-pyramids of the gyrus cinguli there were evaluated lightmicroscopically for every group: length, number and distribution of spines on the main apical dendrites; on the apical oblique dendrites, too, these measures were made in the groups of four weeks of age (experimental and control animals). Main results are: 1. Rearing in the dark from birth up to the fourth week of age, i.e. during the early period of the postnatal brain development causes a growing-inhibition: the number of apical oblique dendrites (first order) was significantly decreased in comparison with the controls. The apical spines-values are not significantly altered. 2. Rearing in the dark from birth up to the ninth week of age as well as during the later postnatal development (from the fifth up to the ninth week) cause a statistically significant increase of spines values on the main apical dendrite. 3. These findings are discussed from a functional point of view and with the references.

[Quantitative study of the apical dendritic spines in the cingulate lamina-V-pyramid neurons of the rat following oral application of alcohol]. / Quantitative Untersuchung über apikale Dendriten-Spines an cingulären Lamina-V-pyramidenneuronen der Ratte nach oraler Alkohol-Applikation.

The question answered in this paper is whether the apical dendritic spines-values of lamina-V-pyramidal cells of the gyrus cinguli of the rat are changed as a result of the oral application of ethanol. Alcohol-application causes a statistically significant increase of apical spines, especially at the main dendrite when given during the early postnatal development phase, where the brain is still impressible. The results are discussed as compensatory achievement of the not degeneratively changed neurons, while other pyramids show signs of degeneration. The conclusions were compared with the results of Kunz et al. (1976), who investigated the ethanol-effects on hippocampal pyramids.

[Effect of sensory stimulation on the lamina V pyramidal neurons of the gyrus cinguli in the rat]. / Der Einfluss sensorischer Stimulation auf die Lamina V-Pyramidenneurone des Gyrus cinguli der Ratte.

UNLABELLED: Three groups of Wistar-rats were exposed to permanent noise (80 db) during different periods in their postnatal life: the first group was exposed starting from birth for a period of four weeks, the second one from birth up to nine weeks of age and the third group from the fifth up to the ninth week postnatal. A fourth group (control animals) was reared under normal laboratory conditions. After the experiments the brains were exposed to a modified GOLGI-method. In lamina-V-pyramids of the gyrus cinguli lightmicroscopical results: length, number and distribution of spines on the main apical dendrites and on the apical dendritic branches where evaluated. MAIN RESULTS: 1. Permanent noise during the early postnatal development phase of the brain of rats (from birth up to the fourth week of age) causes a statistically significant increase of apical spines. The spines-values are 20% above those of the control animals. 2. Permanent noise from birth up to the ninth week of age or applied only during the later postnatal period (from the fifth week up to the ninth week of age) does not significantly alterate the spines-value. 3. The results are estimated as a consequence of extreme environmental factors causing effects, comparable with an universal stress reaction. Conclusions were discussed in comparison to the results of other authors.

[Quantitative study of primitive pyramidal cells in rat anterior cingular cortex]. / Quantitative Untersuchungen an primitiven Pyramidenzellen in der vorderen cingulären Rinde der Ratte

In the present paper the primitive pyramidal cells of the Vthlayer of the anterior cingulate cortex in adult male white rats were analyzed quantitatively and compared statisticaly with large pyramidal cells of the same region. The number of dendrites, the total lengths of dendrites, the number of spines and the density of spines -- according to the order of dendrites -- show similarity between the primitive pyramidal cells and the large pyramidal cells the latter one exhibit the higher values. The curves of distribution of the various density of spines along the apical main dendrite of both cell types are similar in shape, too. The lengths of the dendritic fields and their basal spines-values are without significant distinction for both cell types, however there are more dendritic fields in large pyramidal cells. Refered to a complete pyramidal neuron they can say: there are significantly higher values in large pyramidal cells for the number of dendrites and their total lengths, the total number of spines, the number of branching sites sites and free endings. However the density of spines of the complete neuron has no significant differences between primitive and large pyramidal cells.

[Quantitative study of dendritic tree of large (regular) pyramidal cells of lamina V in rat anterior cingular cortex]. / Quantitative Untersuchungen am Dendritenbaum von grossen (regulären) Pyramidenzellen der Lamina V im Bereich der vorderen cingulären Rinde der Ratte

At three month old male rats the dendritic trees of 36 large pyramidal cells in the Vth layer of the anterior cingulate cortex were analyzed quantitatively by means of the Golgi-Kopsch method. 12 pyramidal cells were localized at the medial border of the regio praecentralis (neocortex), 12 cells were localized in the adjacent mesoarchicortex, 12 cells were localized in the mesoarchicortex, which are three subregions of the anterior cingulate cortex. By means of a varianz-analysis the values of the three subregions were compared, in order to verify a supposed gradient of differentiation. 1. In the three subregions basal the number and the branching behaviour of the dendrites are greater than apical. The pyramidal cells of the neocortex and of the mesoneocortex have significantly more basal dendrites of the 1st, 2nd, 3rd, and 4th order than those of the mesoarchocortex. There are significantly more apical dendrites of the 1st and 2nd order at pyramidal cells of the neocortex compared with the two other subregions. 2. The total lengths of the dendritic branches are in proportion to the dendritic numbers of the corresponding orders. There are following tendencies for the three subregions: the number and length of apical dendrites decrease with the increasing number of order, basally, however, the number and length first increase and than decrease. 3. The total length of all basal dendrites of a pyramidal cell is largest in the mesoneocortex, than follows the neocortex, least values they find in the mesoarchicortex. There are significant differences between every one of the three subregions. The values of the total dendritic tree of a pyramidal cell (total dendritic length, total number of dendrites, volume of the dendritic tree, number of branching sites and free endings, total apical dendritic length) show significant differences between neocortex and mesoarchicortex as well as between mesoneocortex and mesoarchicortex. There are no significant differences between noecortex and mesoneocortex. The values of the total dendritic tree demonstrate that neocortex and mesoneocortex have a similar organization, while the lamina V-pyramidal cells of the mesoarchicortex indicate a significantly smaller and less branched dendritic tree.

[Quantitative studies on the dendritic spine distribution on the lamina-5 pyramidal cells in the anterior gyrus cinguli of the rat]. / Quantitative Untersuchungen über die Dendriten-Spines an den Lamina V-Pyramidenzellen im Bereich der vorderen cingulären Rinde der Ratte

At three months old male rats the spine-distribution of the main dendrite and of the apical and basal dendrites of 36 lamina V-pyramidal cells of the regio cingularis (anterior cingulate cortex) was analyzed (from every subregion -- neocortex, mesoneocortex, mesoarchicortex -- 12 neurons). 1. The limbic pyramidal neurons show the same spine-distribution at their main dendrite as neocortical neurons of other brain regions and other mammal-species do: after an initial segment with poor spines only there follows an rapid increase of the spine-values with an amount at a range of 150 mum from the perikaryon, thereafter spine-values decrease continuously and slowly up the branching into the terminal bundle. 2. Basal and apical lateral dendrites however show another spine-distribution: basally there is an increase of the spine-values from the 1st up to the 3rd order, followed by a decrease at subsequent orders. Apically spine-density decreases from the 1st up to the 4th order. 3. The spine-distribution at the parts of the dendritic tree is discussed as a general biological sign of pyramidal cells. 4. The total number of spines of lamina V-pyramidal cells in the regio cingularis (anterior cingulate cortex) is less than those in the sensomotoric cortex and in the hippocampus, which corresponds with the lower differentiation of the limbic cortex. 5. By means of a variance-analysis the pyramidal spine-values of the three subregions were compared: concerning the total number of spines of a pyramidal neuron there are significant differences between the three subregions; the values are in the ratio of 3 to 2 to 1 (Regio praecentralis agranularis, 2461; mesoneocortex, 1664; mesoarchicortex, 800). The significantly least spine-density of all parts of the dendritic tree you can find in lamina V-pyramidal cells of the mesoarchicortex. 6. The equality of the basal and apical spine-values in the mesoneocortex is due to less specialization of these neurons. 7. The spine-values for a single dendritic field (EDF) show the differences between the limbic subregions clearly: there are significant differences between the three subregions concerning not only the number of spines but also the spine-densities apically and basally.