Genesis and possible dissolution of neuronal lipofuscin

Oxidative damage causes formation of lipofuscin-like substances in the hippocampus of the senescence-accelerated mouse after kainate treatment

We have demonstrated that seizures induced by kainic acid (KA) are, at least in part, mediated via oxidative stress in rats [Life. Sci. 61 (1997) PL373; Brain Res. 853 (2000) 215; Brain Res. 874 (2000) 15; Neurosci. Lett. 281 (2000) 65]. In order to extend our findings, we employed the rodent aging model in this study. After KA treatments (once a day for 5 days; 20,20,20,20 and 40 mg/kg, i.p.), several parameters reflecting neurotoxic behaviors, oxidative stress [malondialdehyde (MDA) and protein carbonyl] and aging (lipofuscin-like substances) were compared between senile-prone (P8) and resistant (R1) strains of 9-month-old male senescence-accelerated mice (SAM). KA-induced neurotoxic signs as shown by mortality and seizure activity were more accentuated in the SAM-P8 than in the SAM-R1. Levels of MDA and carbonyl are consistently higher in the hippocampus of SAM-P8 than that of SAM-R1. Significant increases in the values of MDA and carbonyl were observed 4 h or 2 days after the final KA administration. This finding was more pronounced in the SAM-P8 than in the SAM-R1. Although a significant loss of hippocampal neurons was observed 7 days post-KA, at this time the MDA and carbonyl content had returned to near control levels. In contrast, fluorescent lipofuscin-like substances and lipofuscin granules were significantly increased 7 days after KA treatments. Therefore, our data suggests that mice in the senescence model are more susceptible to KA-induced seizures/oxidative damage, and that oxidative damage could be one of the casual factors in the accumulation of lipofuscin.

Quantitative ultrastructural evidences suggest no age-related changes in biosynthesis and processing within parvocellular cells of the paraventricular nucleus in hamsters

The parvocellular neurons of the parvocellular division of the paraventricular nucleus (PVPA) were studied in hamsters at six point ages (from 3 to 30 months old). Standard manual morphometric techniques were used to obtain data of parvocellular activity including nuclear and nucleolar size, as well as the percentage of the cell occupied by Golgi apparatus (GA), mitochondria and rough endoplasmic reticulum (RER). Other directly age-related parameters like amounts of nuclear invagination and lipofuscin have also been studied. No significant differences in the measured subcellular components were detected among groups studied, except slight increases in lipofuscin. No age-related changes were found in the synthesizing apparatus, but a significant decrease in the cell area was observed in older groups. This finding could suggest a reduction in absolute terms in the protein synthesis of the parvocellular neurons during aging. Ultrastructural morphometric observations in parvocellular neurons are discussed in relation to synthesizing activity and hormone production during aging.

The magnocellular neurosecretory system of the hamster hypothalamus: an ultrastructural and morphometric study during lifetime

A quantitative study regarding the age-related changes occurring in the nucleus and the somatic organelles of neurosecretory magnocellular neurons of the hypothalamo neurohypophyseal system (HNS) was carried out in the hamster at six age-points during animal life. The magnocellular cells of both parts of the supraoptic nucleus (SON) and the paraventricular nucleus (PVN) of male Syrian hamsters between 3 and 30 months of age were examined ultrastructurally. Cells of all age groups present the same morphological ultrastructure. Standard manual morphometric techniques are used to calculate the following parameters related directly or indirectly with cellular activity: nuclear area, nucleolar area, nuclear invagination index and volumetric fractions of some intracellular structures (Golgi apparatus, mitochondria, rough endoplasmic reticulum and lipofuscin). With respect to the cell nucleus, the parameters are not modified during aging. No significant differences in the volume density of subcellular components, except lipofuscin, were detected at the age groups studies. However, there is a positive linear trend among all parameters and age except for the rough endoplasmic reticulum. Our results suggest maintenance of the synthetic activity of the magnocellular neurons in the hamster during aging but in no case an increase in their metabolic activity.

Ultrastructural changes in the hydropic cochlea of the guinea-pig

Transmission electron microscopy of the cochlear organ of Corti in experimental endolymphatic hydrops revealed two principal features. Starting 1 month after induction of hydrops, osmiophilic inclusions thought to represent lipofuscin accumulation were frequently observed in the subcuticular cytoplasm of the outer hair cells along the length of the cochlea. Starting 3 months after induction of hydrops the efferent terminals on the outer hair cells appeared to be vacuolated. These data suggest that oxidative insult is likely to contribute to the pathology associated with endolymphatic hydrops and thus that free radical scavengers might be useful in the treatment of Menière's disease patients. In addition the early modification of the efferent innervation of the hydropic cochlea might underlie the known hypersensitivity to various insults, including noise stimulation, glycerol administration and hypoxia.

Ultrastructural morphometric analysis of lipofuscin in pyramidal cells of the human Ammon's horn

Lipofuscin is a waste product of autolysosomal metabolism. The amount of lipofuscin in the cytoplasm depends on cell type, cell function and age. In most studies, either the fluorescent or the stained component of lipofuscin was investigated. Quantitative morphological investigations of the lipofuscin composition separated into the vacuolar and granular component were missing. For the hippocampal pyramidal cells we have determined the lipofuscin quantity and, separately, the vacuolar and granular component at the ultrastructural level. The hippocampal subfields CA 1, CA 2, CA 3 and CA 4 were observed at the ages 20, 40, 60 and 80 years (+/-3 years). Quantitative determinations of the vacuolar and granular component of neuronal lipofuscin in pyramidal cells were performed with a semi-automatic image analysis system. In CA 1 pyramidal cells the lipofuscin content was significantly lower than in the other sectors, which did not differ significantly in their lipofuscin content. The amount of the granular component in relation to the vacuolar component in CA 1 was larger than in the other sectors. With advancing age the lipofuscin content per cell increased. The vacuolar component of all hippocampal subfields experienced a larger increase than the granular component. Consequently the relation of the vacuolar and granular component changed; the relative amount of the vacuolar component increased, while that of the granular component decreased with age. The differences between sector CA 1 and the other hippocampal subfields were discussed with reference to differences of metabolic and functional activity of the neurons. Cytoprotective factors like Calbindin D28k were discussed for CA 1.

The effects of piracetam on lipofuscin of the rat cerebellar and hippocampal neurons after long-term alcohol treatment and withdrawal: a quantitative study

There is a growing body of evidence indicating that chronic alcohol consumption induces morphological changes in the central nervous system (CNS) similar to those observed during brain senescence, including an increased formation of lipofuscin. In addition, it was also found that alcohol withdrawal does not reverse these changes. On the contrary, most of the alterations observed during alcohol consumption worsen as happens with the increased lipofuscin formation. Thus, using our model of alcohol feeding and withdrawal, we decided to examine the effects of different drugs said to offer neuronal protection during CNS degenerative processes. The action of piracetam, a cyclic derivate of GABA and commonly used as a nootropic agent, was tested by studying the lipofuscin accumulation on the cerebellar Purkinje and hippocampal CA3 pyramidal cells in alcohol-treated and withdrawn rats. Piracetam was found to markedly decrease the formation of neuronal lipofuscin. Whatever the functional implications of this pigment, its reduction in piracetam-treated animals might be related either to a protective effect on the intraneuronal membranous system or to an antioxidant property of this molecule.

Age-related changes in Schwann cells of the internal branch of the rat superior laryngeal nerve

While previous studies have examined the role of neurons in age-related changes of laryngeal sensory nerve function, investigators have not focused on the significant role of Schwann cells in the aging process. This investigation used an electron microscopic morphometric technique to systematically study Schwann cells of the internal branch of the superior laryngeal nerve of three Wistar rat age groups: young = 3 to 5 months; old = 25 months; very old = 29 to 31 months. In Schwann cells of myelinated axons, a substantial and significant reduction (p = 0.0127) in mitochondrial volume fraction was found between the young and old groups, and also between the young and very old groups (young = 0.0034, old = 0.00175, very old = 0.0019). The volume fraction of compact myelin also showed a trend (p = 0.0683) toward decreasing with age. The volume fractions of cytoplasm, nuclei, and lipofuscin granules showed no significant age-related changes (lipofuscin in myelinating Schwann cells: young = 0.0025, old = 0.0020, very old = 0.0051; lipofuscin in non-myelinating Schwann cells: young = 0.012, old = 0.0061, very old = 0.0051). Our observations on mitochondria lead to two possible conclusions regarding energy availability in aged Schwann cells. One possibility is that aged cells have a decreased energy requirement, which is reflected in the decreased mitochondrial densities in old and very old specimens. The other possibility is the reduced mitochondrial volume fractions are independent of cellular energy requirements and are indicative of some aging or pathologic process.(ABSTRACT TRUNCATED AT 250 WORDS)

Schwann cells associated with vestibular ganglion cells in the aging rat

The purpose of this study was to quantify any age-related change in the components of Schwann cells associated with vestibular ganglion cells: adperikaryonal Schwann cell cytoplasm, myelin bubbles, compact myelin, Schwann cell lipofuscin, or mitochondria in addition to extracellular intraganglionic space. Studies were carried out in young (Y, 3 to 5 months of age, N = 6), old (0, 24 to 26 months of age, N = 3), and very old (VO, 28 to 31 months of age, N = 6) female Wistar rats using point counting stereologic techniques. Recent reports have demonstrated age-related increases in the peripheral nerve counterparts to the following entities: adaxonal Schwann cell cytoplasm, myelin bubble, endoneurial space, and a decrease in Schwann cell mitochondria. Our results indicate no age-related change in the volume fraction of extracellular intraganglionic space (Y, 0.179 +/- 0.04; O, 0.174 +/- 0.049; VO, 0.205 +/- 0.043), adperikaryonal Schwann cell cytoplasm (Y, 0.026 +/- 0.008; O, 0.019 +/- 0.003; VO; 0.028 +/- 0.007), myelin bubble (Y, 0.004 +/- 0.003; O, 0.011 +/- 0.009; VO, 0.006 +/- 0.002), Schwann cell lipofuscin (Y, 0.002 +/- 0.001; O, 0.004 +/- 0.003; VO, 0.002 +/- 0.001), or mitochondria (Y, 0.194 +/- 0.019; O, 0.208 +/- 0.024; VO, 0.205 +/- 0.04). The only age-related change was an increase in compact myelin (Y, 0.006 +/- 0.001; O, 0.008 +/- 0.006; VO, 0.011 +/- 0.004). These findings differ from those of the peripheral nerve.(ABSTRACT TRUNCATED AT 250 WORDS)

Quantification of age pigments (lipofuscin)

1. Three methods have hitherto been applied for age pigment quantification: (a) numerically from micrographs; (b) fluorimetrically from histological sections; (c) spectrofluorimetrically from dissolved age pigments. 2. The spectrofluorimetric method is at present the most commonly used technique for quantification of age pigments. 3. By comparing the related publications since introduction of the spectrofluorimetric method, it has become apparent that few authors specify fluorimetrically significant factors, such as temperature and pH which influence the sample fluorescence during measurement. 4. Recent developments in fluorimetrical age pigment quantification using chloroform/methanol as solvent have additionally revealed the necessity to measure and present the age pigments dissolved in both phases: the polar and non-polar solvents.

Age-related change in the multiple unit activity of the rat brain parietal cortex and the effect of centrophenoxine

In this study, spontaneous multiple unit activity (MUA, action potentials derived simultaneously from a number of neurons in a given brain region) was recorded through electrodes chronically implanted in the parietal cerebral cortex of the rats of 1, 3, 6, 9, 12, and 26 months of age (cross-sectional study). Electrophysiological recordings were obtained from unrestrained conscious rats using standard techniques. The results indicated that multiple unit activity was decreased with aging (senescence). Maximum firing rate (MUA counts) was found at the age of 3 months. At 6 months of age, the MUA was decreased by about 30%, while during 6 to 12 months of age the activity seemed to remain unchanged. At 26 months of age the firing rate was, however, further decreased (about 40%). Centrophenoxine administration led to an increase in MUA in the rats of 12 and 26 months of age. The results, thus, further showed that centrophenoxine, a nootropic drug known for its antiaging effects in experimental animals as well as in humans, also manifested beneficial effects electrophysiologically. The data presented in this work are new and significant, since although age effects on gross electrophysiological signals (EEG, evoked potentials, etc.) are known, the aging changes in cellular level electrophysiological signals (action potentials) have not been generally studied particularly in conscious animals.

Chronic alcohol consumption induces lipofuscin deposition in the rat hippocampus

Previous investigations have suggested that chronic alcohol consumption accelerates a number of age-related changes in the cerebellar cortex and hippocampal formation. In the cerebellum, alcohol-feeding has been shown to accelerate the intracellular deposition of lipofuscin. In order to determine whether alcohol administration has a similar effect on hippocampal lipofuscin deposition, we studied the pattern of lipofuscin deposition in alcohol-fed rats for periods of 1, 3, 6, 12 and 18 months and compared the results with those obtained in the respective pair-fed controls. A precocious and progressive deposition of lipofuscin pigment was found in both CA1 and CA3 neurons in Ammon's horn hippocampal fields after 3 and 6 months of alcohol feeding, respectively. These results parallel those observed during normal aging and reinforce the hypothesis of a close link between chronic alcohol consumption and a premature nerve cell aging.

Effects of centrophenoxine on lipofuscin in the retinal pigment epithelium of old mice

The effects of centrophenoxine on the retinal pigment epithelium (RPE) of 17 month old female mice have been studied. Animals were injected subcutaneously for 3 months (60 injections) with the drug (0.1 mg/g of body wt) daily in 0.1 M phosphate buffered saline at pH 7.0. The morphological changes in the pigment layers of the retina of both eyes were studied by light and electron microscopy and the lipofuscin pigment was demonstrated by its autofluorescence and ultrastructural characteristics. There was a significant reduction of the lipofuscin pigment in the treated animals, but the melanin pigment remained unchanged. The lipofuscin granules also appeared less osmiophilic and showed a greater preponderance of membranes and vacuoles. Although the precise mechanism of action of the drug is not clear, an increased protective function of the pigment epithelium by the drug has been suggested.

Reduction of lipofuscin by centrophenoxine and chlorpromazine in the neurons of rat cerebral hemisphere in primary culture

Cells from neonatal rat cerebral hemispheres were dispersed by trypsin and cultured for 32 days. Histochemical, fluorescence, and electron microscopic analyses demonstrated that lipofuscin pigments increased in neuronal and non-neuronal cells in primary culture according to the lapse of time. When centrophenoxine (10(-4) or 5 X 10(-4) M) or chlorpromazine (10(-6) or 10(-5) M) was added to the medium, the accumulation of lipofuscin pigments in neurons was significantly reduced. However, the effects of these agents were not detected in non-neuronal cells.

Lipofuscin in the cerebellar cortex of albino rats: an electron microscopic study

The ultrastructure of autofluorescent, PAS-positive lipofuscin in Purkinje, granule, Golgi epithelial, basket and stellate, microglial and perivascular cells in the cerebellar cortex of senescent rats is described. The membrane-bounded pigment is composed of three elements: 1) electron-lucent homogeneous droplets, 2) a granular matrix and 3) intensely osmiophilic patches. The proportions of these three components vary between cell types and one can grossly differentiate a neuronal and a glial lipofuscin. The lipofuscin granules of stellate and perivascular cells are different from lipofuscin of other cerebellar neurons and glia. It can be concluded from these morphological observations that each cerebellar cell type has its distinct lipofuscin.

The mode of mitochondrial degeneration in gliomas

Morphologically abnormal mitochondria from human glial tumours are described. For each tumour both the appearances of the mitochondria, and the subsequent mode of degeneration and formation of osmiophilic pigment is characteristic. The significance of these observations is discussed, and it is suggested that the mode of degeneration observed reflects directly a fundamental abnormality in composition compared to normal mitochondria.

Immunofluorescence studies across the leprosy spectrum

Forty biopsies from skin lesions of untreated (24) and treated (16) leprosy patients, representing the whole leprosy spectrum, were examined by means of immunofluorescence (IF) methods. Only few or no cells staining with FTC-labelled antihuman immunoglobulin antisera were found in the lesional skin of all patients examined. Sparse IgM-deposits along the basement membrane of the epidermis were observed in a few borderline lepromatous and lepromatous patients. Complement deposits along the basement membrane of the epidermis and in the vessel walls were found in tuberculoïd as well as in lepromatous patients. Complement and in a lesser number IgG-deposits were observed around sweat glands and sometimes around sweat gland ducts and other skin appendages. Autofluorescing macrophages were noted in patients at the lepromatous side of the leprosy spectrum; approximately half of these patients showed complement deposits in an around these cells.

Centrophenoxine: effects on aging mammalian brain

A study was made of the effects of centrophenoxine on the learning and memory of old mice. The results were correlated with changes in neuronal lipofuscin in the cerebral cortex and hippocampus. Old female mice (11-12 months) were treated with centropheoxine for three months and their learning and memory were tested in a T-maze. The number of trials required to attain the criterion in the 20 treated old mice were compared with those for 20 untreated mice of the same age and for 20 younger untreated mice. The treated animals learned the task with significantly fewer trials, and also exhibited a reduction of neuronal lipofuscin pigment in both the cerebral cortex and the hippocampus. The changes in lipofuscin were demonstrated by study of the characteristic autofluorescence, and by histolchemical and ultrastructural (electron microscope) observations.

Dense core mitochondria in peripheral ganglia of man

Neuronal perikarye of peripheral ganglia contained unusual dense core mitochondria that were not seen in other cell types or tissues of the same individual. They were found in several patients autopsied with GM1-gangliosidosis and neuronal ceroid-lipofuscinosis. Previous observations on human sympathetic ganglia, obtained by biopsy, and our findings suggest that these dense core mitochondria might represent a rare but regular feature of neuronal perikarya in peripheral ganglia of man.

Ultrastructure of Lewy bodies in the stellate ganglion

The Lewy body, a characteristic nerve cell inclusion in idiopathic parkinsonism, was examined by electron microscopy in the stellate ganglion, obtained from 9 patients at autopsy. Three main forms of Lewy bodies or Lewy body-related structures were demonstrated: A.Rare filamentous Lewy bodies, similar to Lewy bodies in the central nervous system. B. Granular Lewy bodies in nerve cell processes. C. Abnormal nerve cell processes, filled with heterogenous material. Large dense core vesicles were prominent in the last 2 forms. None of these abnormalities were found in 2 control groups consisting of 9 parkinsonism cases without central nervous system Lewy bodies, and 17 cases without parkinsonism. The filamentous Lewy body (type A) was found in the perikaryon and was surrounded by neuromelanin, whereas the other forms (type B and C) were seen in nerve cell processes. Mitochondrial inclusions, present mainly, but not exclusively, in neuromelanin-containing cells, were not related to Lewy body formation or to parkinsonism.

Morphological changes in aging cell lines of Paramecium aurella. I. Alterations in the cytoplasm

Electron microscopical examination of aging P. aurelia revealed that definitive changes occur in the cytoplasm of old cells. There was an increase in the number of mitochondria and lysosomal bodies as well as the appearance of large dense bodies and autophagous vacuoles. The mitochondria were altered morphologically and many appeared to be coalesced with lysosome-like bodies and were also observed to be degenerating within autophagous vacuoles. The large dense bodies were considered to be similar to the lipofuscin or age pigments reported in other aging cells. The relationship of the large dense bodies to the lipofuscin pigments and their probable origin are discussed as is the involvement of the cytoplasm in the aging death process in P. aurelia.

Changes in lysosomes during ageing of parenchymal and nonparenchymal liver cells

Intact and viable parenchymal and non-parenchymal liver cell preparations were isolated by enzyme perfusion techniques from young and old rats. The distribution of the lysosomal enzymes acid phosphatase, beta-galactosidase, cathepsin D, acid DNAse, and arylsulphatase B over parenchymal and non-parenchymal cells was determined. In addition, morphological and morphometric changes which occur in parenchymal cells with age were investigated. All lysosomal enzymes studied are present in both cell classes, but non-parenchymal cells possess much ligher activities per mg protein than do parenchymal cells. This phenomenon is most pronounced for cathepsin D with a 13-times higher specific activity in non-parenchymal cells. Electron microscopic observations demonstrated that the lysosomal activities in non-parenchymal cells can be attributed mainly to the large and numerous lysosomal structures in Kupffer cells. Parenchymal cells from old rats have higher lysosomal enzyme activities per mg protein than do hepatocytes from young rats. This observation is in agreement with the general increase with age in the cytoplasmic volume fraction occupied by lysosomal structures in parenchymal cells. In general, non-parenchymal cells show no increase in specific enzyme activities with age. The results obtained suggest an increase in the heterogeneity--in both appearance and enzyme content--of the lysosomal structures in parenchymal cells with age.