The occurrence of corpus amylaceum (polyglucosan body) in diabetes mellitus

Deleterious effects of neuronal accumulation of glycogen in flies and mice

Under physiological conditions, most neurons keep glycogen synthase (GS) in an inactive form and do not show detectable levels of glycogen. Nevertheless, aberrant glycogen accumulation in neurons is a hallmark of patients suffering from Lafora disease or other polyglucosan disorders. Although these diseases are associated with mutations in genes involved in glycogen metabolism, the role of glycogen accumulation remains elusive. Here, we generated mouse and fly models expressing an active form of GS to force neuronal accumulation of glycogen. We present evidence that the progressive accumulation of glycogen in mouse and Drosophila neurons leads to neuronal loss, locomotion defects and reduced lifespan. Our results highlight glycogen accumulation in neurons as a direct cause of neurodegeneration.

Heat shock protein 60 in corpora amylacea

Heat shock protein 60 representation in the corpora amylacea of the brain was investigated in five different neurological diseases. In the cases with cerebral infarct, amyotrophic lateral sclerosis, multiple sclerosis, acute disseminated encephalomyelitis and primary tumors of the nervous system the corpora amylacea showed similar appearance with strong HSP-60 positivity in all investigated disorders at the predilection sites. In the inflammatory diseases, besides corpora amylacea, several cellular elements exhibited HSP-60 immunostaining too. In these cases, the widespread HSP-60 immunoreactivity associated with relative moderate corpora amylacea production as compared to other diseases. From this contradiction we concluded the corpora amylacea participate in the cellular stress reaction but stress protein synthesis certainly is not the primary event in corpora amylacea formation. In the development of the corpora amylacea the incipient process is most probably degenerative in nature, which later on is accompanied by stress protein synthesis and slow growing of these round structures designated for a protective role in the brain. However, the role of the stress protein synthesis in the corpora amylacea formation and growth was not unequivocally answered in this study. It is necessary to perform further comparative investigations of the stress protein representation and corpora amylacea formation in different diseases which may help in discovering useful pathogenetic data and the biological role of this degenerative structure.

Localization of identified advanced glycation end-product structures, N epsilon(carboxymethyl)lysine and pentosidine, in age-related inclusions in human brains

The recent identification of age-related accumulation of advanced glycation end-products (AGE) of the Maillard reaction in neurons and vessels of the human brain suggests the involvement of AGE in the aging process. A variety of inclusions such as lipofuscin granules, corpora amylacea, Hirano bodies, granulovacuolar degenerations and ubiquitin-positive granular structures are found in the aged human brain. These age-related inclusions contain insoluble and non-degradable proteins. Advanced glycation end-product-modified proteins are also known to be insoluble and protease resistant. The similarity between proteins in such inclusions and AGE-modified proteins suggests the presence of AGE in inclusions. To investigate this possibility, the presence of two known AGE structures, N epsilon(carboxymethyl)lysine (CML) and pentosidine, was examined in age-related inclusions. Immunohistochemical examination of the medial temporal area of brain tissues obtained at autopsy from seven non-demented elderly individuals demonstrated positive reactions in lipofuscin granules and corpora amylacea but not in other inclusions for anti-CML and anti-pentosidine antibodies. As CML and pentosidine are glycoxidation products among AGE, the results suggest that glycation and/or oxidation may be involved in the formation of lipofuscin granules and corpora amylacea.

Corpus amylaceum (polyglucosan body) in the peripheral olfactory system

Peripheral part of the olfactory system (bulb and tract) was investigated for the occurrence of corpus amylaceum (CA) (polyglucosan body) in 296 (281 pathological and 15 control cases) autopsied human brains. No significant differences were found in the incidence between the various age groups above 40 years or between different disease groups and the controls. The predominance of CA in the olfactory tract and its loose correlation with age at this localization over 40 years of age could be resulted by various factors, including the extremely rich astrocytic and capillary network in the intermediate zone, and the proximity of the olfactory tract to the external environment, which may result in the protective role of CA. The role of stress was proved by the HSP-60 positivity of CA.