Corpora amylacea in the peripheral nerve axons

From corpora amylacea to wasteosomes: History and perspectives

Corpora amylacea (CA) have been described in several human organs and have been associated with ageing and several pathological conditions. Although they were first discovered two centuries ago, their function and significance have not yet been identified. Here, we provide a chronological summary of the findings on CA in various organs and identify their similarities. After collecting and integrating these findings, we propose to consider CA as waste containers created by specific cells, which sequester waste products and foreign products, and assemble them within a glycan structure. The containers are then secreted into the external medium or interstitial spaces, in this latter case subsequently being phagocytosed by macrophages. This proposal explains, among others, why CA are so varied in content, why only some of them contain fibrillary amyloid proteins, why all of them contain glycan structures, why some of them contain neo-epitopes and are phagocytosed, and why they can be intracellular or extracellular structures. Lastly, in order to avoid the ambiguity of the term amyloid (which can indicate starch-like structures but also insoluble fibrillary proteins), we propose renaming CA as "wasteosomes", emphasising the waste products they entrap rather than their misleading amyloid properties.

Adult polyglucosan body disease: A case report of a manifesting heterozygote

A 62-year-old man developed progressive gait instability, bladder dysfunction, proximal weakness, distal sensory loss, and mild cognitive impairment over 6 years. Neurologic examination revealed upper and lower motor neuron dysfunction in the lower extremities, with distal sensory loss. Electrodiagnostic studies, magnetic resonance imaging of the brain, and sural nerve biopsy were consistent with adult polyglucosan body disease. Biochemical and genetic analyses demonstrated reduced glycogen brancher enzyme levels associated with a heterozygous point mutation (Tyr329Ser or Y329S) in the glycogen brancher enzyme gene on chromosome 3. Mutational heterozygosity in the glycogen brancher enzyme gene has not been previously reported as a cause for this rare disease. A review of the clinical presentation, pathogenesis, etiology, and diagnosis of this disease is presented.

Probable adult polyglucosan body disease

Adult polyglucosan body disease is a clinicopathologic entity characterized by progressive upper and lower motor neuron dysfunction, sensory loss in the lower extremities, sphincter dysfunction, and occasionally dementia. Pathologically, numerous large polyglucosan bodies are noted in peripheral nerves, cerebral hemispheres, and the spinal cord, as well as in other systemic tissues. We present a case of probable adult polyglucosan body disease based on clinical history and examination, magnetic resonance images, and sural nerve biopsy findings.

Experimental induction of corpora amylacea in adult rat brain

Corpora amylacea (CA) are glycoproteinaceous inclusions that accumulate in astroglia and other brain cells as a function of advancing age and, to an even greater extent, in several human neurodegenerative conditions. The mechanisms responsible for their biogenesis and their subcellular origin(s) remain unclear. We previously demonstrated that the sulfhydryl agent, cysteamine (CSH), promotes the accumulation of CA-like inclusions in cultured rat astroglia. In the present study, we show that subcutaneous administration of CSH to adult rats (150 mg/kg for 6 weeks followed by a 5-week drug-washout period) elicits the accumulation of CA in many cortical and subcortical brain regions. As in the aging human brain and in CSH-treated rat astrocyte cultures, the inclusions are periodic acid-Schiff -positive and are consistently immunostained with antibodies directed against mitochondrial epitopes and ubiquitin. Our findings support our contention that mitochondria are important structural precursors of CA, and that CSH accelerates aging-like processes in rat astroglia both in vitro and in the intact brain.

Experimental induction of corpora amylacea-like inclusions in rat astroglia

Corpora amylacea (CA) are glycoproteinaceous inclusions that accumulate in the human central nervous system during normal ageing, and to an even greater extent in Alzheimer's disease and other neurodegenerative disorders. They are particularly prominent in subpial and subependymal regions, and are most commonly located within astrocytes and their processes. We previously demonstrated that human CA share many tinctorial and histochemical properties in common with Gomori-positive cytoplasmic granules which accumulate in periventricular astrocytes of the ageing vertebrate brain and in rat astroglial cultures exposed to the sulphydryl agent, cysteamine (CSH). In the present study, long-term exposure of neonatal rat astrocyte cultures to CSH resulted in the formation of large spherical, PAS-positive cytoplasmic inclusions which are highly reminiscent of, if not identical to, human CA. As in the case of human CA and Gomori-positive astrocyte granules, the CSH-induced CA-like inclusions exhibit non-enzymatic peroxidase activity and consistent immunolabelling with antibodies directed against the mitochondrial protein, sulphite oxidase. Taken together, our findings suggest that progressive mitochondrial damage and macroautophagy play an important role in the biogenesis of CA (and Gomori-positive granules) in astrocytes of the ageing periventricular brain.

Mitochondrial constituents of corpora amylacea and autofluorescent astrocytic inclusions in senescent human brain

Corpora amylacea (CA) are cytoplasmic inclusions that accumulate in human brain in the course of normal aging, and to an even greater extent, in Alzheimer's disease and other neurodegenerative conditions. In senescent and Alzheimer-diseased human brains, astrocytes in limbic and periventricular regions exhibit red autofluorescent inclusions, homologous to Gomori-positive astrocyte granules previously described in the brains of aging rodents and other vertebrates. We have shown that Gomori inclusions in situ and in culture are derived from autophagocytosed mitochondria exhibiting iron-mediated peroxidase activity. In the human brain, the autofluorescent inclusions share many properties with CA. Both types of inclusion progressively accumulate in periventricular regions with advancing age, are largely astrocytic in origin, and contain various heat shock proteins and ubiquitin. Using histochemistry in conjunction with cofocal microscopy, we demonstrated that both CA and the red autofluorescent granules exhibit non-enzymatic peroxidase activity and an affinity for CAH and PAS. The only major divergent histochemical feature between the Gomori-positive astrocyte granules and CA is the presence of orange-red autofluorescence in the former and the absence of endogenous fluorescence in the latter. On the basis of numerous shared topographic and histochemical features, we hypothesized that CA are largely derived from autofluorescent (Gomori-positive) astrocyte granules which reside in periventricular regions of the senescent CNS. Immunofluorescent labeling and laser scanning confocal microscopy demonstrated consistent colocalization of the mitochondrial proteins, sulfite oxidase, and heat shock protein 60, to both CA and the autofluorescent astroglial inclusions. In addition, both CA and the autofluorescent astrocyte granules exhibit staining for DNA which colocalizes to mitochondrial antigens and therefore likely represents mitochondrial nucleic acid in dual-labeled preparations. These observations suggest that a) Gomori-positive astrocyte granules in human brain are homologous to those described in rodents, b) Gomori-positive granules may be structural precursors of CA in senescent human brain, and c) in the aging human brain, degenerate mitochondria within periventricular astrocytes give rise to autofluorescent cytoplasmic granules and corpora amylacea.

Chronic demyelinating neuropathy and intra-axonal polyglucosan bodies

In this study we evaluated the relationship between polyglucosan bodies and peripheral nerve lesions. The biopsied sural nerve from a patient with late-onset chronic sensori-motor neuropathy showed many intra-axonal polyglucosan bodies and segmental demyelination/remyelination. The formation of Schwann cell hyperplasia around the demyelinated axons was found at the sites of polyglucosan bodies. These findings suggest that demyelinating neuropathy is a part of the spectrum of the diseases characterized by the accumulation of polyglucosan bodies within cellular compartments.

Corpora amylacea in glaucomatous and non-glaucomatous optic nerve and retina

We studied the occurrence, location, and size of corpora amylacea (CA) in periodic acid-Schiff (PAS)-stained histological sections of the retina and optic nerve. The glaucoma group included 48 blind eyes obtained from 48 patients (mean age: 64 +/- 13.9 years; range 26-83 years) with advanced secondary angle-closure glaucoma. The non-glaucomatous group consisted of 45 non-glaucomatous eyes from 45 patients (mean age: 62.1 +/- 12.2 years, range 34-78 years) suffering from malignant melanoma of the choroid, and six autopsy eyes obtained from young individuals (age range 2.5-29 years). The mean diameter of CA at the level of the retinal ganglion cells (retrolaminar: 10.92 +/- 5.15 microns, intralaminar: 10.97 +/- 5.04 microns, prelaminar: 9.17 +/- 4.53 microns, nerve fiber layer: 8.56 +/- 4.27 microns) was significantly larger (P < 0.0001; Wilcoxon-Mann-Whitney test) than their size at the level of the bipolar cells (inner plexiform layer: 3.79 +/- 1.30 microns). The count of CA in sections from non-glaucomatous subjects aged 2.5 to 78 years (45 eyes with malignant melanoma and 6 autopsy eyes) increased significantly (P < 0.01) with advancing age. CA occurred significantly more often (P < 0.0001) in eyes with melanoma (45.7 +/- 29.4 per section) than in eyes with glaucoma (4.7 +/- 6.9 per section). These results suggest that CA represent intraneuronal aging products that are diminished in eyes with end-stage glaucoma due to neuronal loss.

Polyglucosan bodies in sural nerve biopsies

The presence of polyglucosan bodies in sural nerves collected over a 16-year period was studied in relation to age, sex, presence of polyneuropathy, and concomitant presence of central nervous system disorder. Polyglucosan bodies have been seen in only one patient without a polyneuropathy. This patient was suffering from Lafora's disease. In all other sural nerves positive for polyglucosan bodies a polyneuropathy was present. Within this group the prevalence of polyglucosan bodies was positively correlated with age, and if a central nervous system disorder was associated, this prevalence was more distinct. With semiquantitative measurements of the surface of polyglucosan bodies a significant correlation was found between age and percentage of large bodies.

Polyglucosan body axonal enlargement increases myelin spiral length but not lamellar number

The area of the unrolled myelin sheet of internodes of myelinated fibers (MF) of peripheral nerve is thought to be determined by axonal caliber and internodal length. We studied the effect of a focal increase of axonal caliber due to the deposition of polyglucosan bodies (PGB), amylopectin-like glucose polymers, on number of myelin lamellae (NL), interlamellar distance (periodicity), and myelin spiral length (MSL) from a sural nerve biopsy specimen of a patient with chronic inflammatory demyelinating polyneuropathy. Axonal area, NL, periodicity, and MSL were estimated within internodes of MF above, at, and below PGB. The axon caliber at the level of the PGB was significantly (P less than 0.002) increased when the PGB was included. At the PGB, NL and their periodicity were not significantly different from those above or below the PGB. The MSL was significantly longer overlying the PGB than it was in the same internode above or below the PGB. Because slippage or stretching of the myelin sheath as well as movement of molecular constituents of myelin is not likely over large distances, localized biosynthesis and assembly of new myelin may explain this increase of MSL.

Polyglucosan bodies in intramuscular motor nerves

The presence of polyglucosan bodies was studied in intramuscular motor nerves of 292 muscle biopsies. These biopsies were classified into five diagnostic categories and investigated for the presence of polyglucosan bodies in relation to age and sex. Their presence was nonspecific in patients over 20 years, the only correlation being with ageing. Under 20 years, their presence pointed to the diagnosis of Lafora's disease. In cases in which both a muscle biopsy and a sural nerve biopsy were performed, the former appeared to contain these polyglucosans more frequently.

Polyglucosan bodies in the sural nerve of a diabetic patient with polyneuropathy

In the sural nerve of a 62-year-old woman with impaired glucose tolerance test and polyneuropathy, many intra-axonal polyglucosan bodies were observed. Polyglucosan bodies have been described in spontaneously or alloxan-diabetic rats, but are not usually observed in human diabetic neuropathy. Since intra-axonal polyglucosan bodies can occur in the sural nerve in various diseases and in aging, they are considered as non-specific changes. Their presence is probably related to a primary axonal neuropathy.

Intra-axonal polysaccharide deposits in the peripheral nerve seen in adult polysaccharide storage myopathy

This is the first report of an adult polysaccharide storage myopathy demonstrating polysaccharide deposits within the axons of the peripheral nerve. Histochemical and electron-microscopic studies revealed that the intra-axonal deposits were basophilic, PAS-positive, diastase-resistant, and composed of filamentous and granular material. The structural similarity among the polysaccharide deposits in our case, amylopectin-like materials in type IV glycogenosis, Lafora bodies, corpora amylacea, and polyglucosan bodies is discussed.

Pleomorphic intra-neuronal polyglucosan bodies mainly restricted to the pallidium. A case report

rare case with pleomorphic intra-neuronal polyglucosan bodies is reported. A 45-year-old man died of gastric carcinoma with extensive visceral involvement. The autopsy showed numerous intra-neural pleomorphic PAS-positive deposits reminiscent of Bielschowsky bodies in the lateral segments of the pallidum, substantia nigra, and brain stem on both sides. Their histochemical properties were consistent with polyglucosan. The bodies were ultrastructurally composed of filamentous structures and seen in perikarya, axons, and dendrites. Occasionally, spotty electron-dense material was seen in the center of the bodies. The filaments were selectively stained with thiocarbohydrazide method after Thiéry, indicating their chief component as glucose polymers. The bodies are compared with Bielschowsky bodies, Lafora bodies, corpora amylacea, and related bodies, and their nature and significance are briefly discussed.

The ultrastructure of intramuscular nerves in amyotrophic lateral sclerosis

Muscle biopsies of 11 patients suffering from amyotrophic lateral sclerosis (ALS) were examined and the i.m. nerves found in seven of them were examined by electron microscopy. In atrophied muscles there was a marked decrease of myelinated fibers. The ultrastructure of the remaining myelinated axons showed changes in the neurofilaments, mitochondria, and vesicles. There was a decrease in the number of unmyelinated fibers as well as the myelinated fibers. Occasionally, there was an increase of unmyelinated fibers containing small fine axons. There were corpora amylacea in unmyelinated axons and banded structures in the extracellular area of the Schwann cells of the unmyelinated fibers. Some of these findings were considered as the ultrastructural features of degeneration and regeneration in i.m. nerves of motoneurons in ALS.

An ultrastructural study of the corpora amylacea of the optic nerve head and retina

We studied corpora amylacea in the optic nerve heads and retinas of four human eyes with increased intraocular pressure by light and electron microscopy. Ultrastructurally they consisted of a mass of filamentous tangle discretely bordered by normal or abnormal axoplasm within an axonal swelling. We found neurotubules, mitochondria, and the accumulation of dense bodies in the axoplasm surrounding the filamentous tangle. We noted ultrastructural similarities between corpora amylacea and cytoid bodies, swollen axons with transport block, and experimentally induced neurofibrillary tangles. We concluded that corpora amylacea are intracellular organelles found in axonal swellings and are not glial in origin, as previously believed. There is a possible relationship between corpora amylacea and distrubance of axoplasmic transport.

Lafora-like bodies in a cat. Case report suggestive of glycogen metabolism disturbances

Lafora-like bodies in an 8-year-old cat were studied light and electron microscopically and histochemically. In addition ot Lafora-like bodies composed of branching filaments, glycogen granules and electron-dense materaisl, abnormal accumulations of glycogen granules attracted attention. The most remarkable features were the developmental processes of the branching filaments originating directly from glycogen granules. Lafora-like bodies in the present study showed ultrastructural, histochemical, and enzymatic similarities to those described in the previous reports in Lafora's disease, glycogenosm is considered to be probably related to the productive mechanism of Lafora-like bodies.

Ultrastructural observations on axonal swelling in the human gracile nucleus

The morphology of the spheroids in human gracile nuclei was studied by light and electron microscopy. Various spheroids encountered in the present study could be classified into three types based on the internal structure: The first one was chiefly composed of many irregular homogeneous dense bodies, multivesicular bodies seemed to deposit multicentrically in an axon in the early stage of "ballon" formation and coalesce to form larger ones. The second was characterized by a marked accumulated of closely approximated mitochondria and dense concentric bodies. In the third the most characteristic findings were neurofibrillary accumulation and aggregations of dense bodies. These findings showed some divergence from those of dystrophic axons and the last two mimic those of degenerative or regenerative axons, which suggested that axonal swelling (including dystrophic axon) is not characteristic reaction of specific disease but rather nonspecific one to a variety of noxious stimuli. With light microscope, it was difficult to distinguish balloons with different structures since they were quite diverse and manifold in their shape, size, appearance and stainability. Intra-axonal corpora amylacea were seen in most cases and their incidence appeared to be nonspecific for any diseases.