Utilization of lectin-histochemistry in forensic neuropathology: lectin staining provides useful information for postmortem diagnosis in forensic neuropathology.

We have investigated the deposition of glycoconjugates in human brain tissue with or without brain disorders. In this review we describe the application of lectin-histochemistry techniques to forensic neuropathology. Lectin staining is able to reveal several kinds of carbohydrate-related depositions in addition to the conventional degenerative changes including senile plaques, neurofibrillary tangles and corpora amylacea. The senile plaques and neurofibrillary tangles were clearly stained by Con A, PSA and GSI lectins, the corpora amylacea which is relevant to repeated brain hypoxia and mitochondrial damage was also easily detected by these and many other kinds of lectins. Amorphous spaces were detected around blood vessels and independently from blood vessels by lectin staining in the white matter from patients with brain disorders or severe edema. The white matter lesions were not considered relevant for forensic pathology, until a large group of cerebral white matter lesions were detected in the elderly with increasing frequency by modern neuro-imaging methods. The spherical deposits were newly detected by lectin staining in the molecular layer of the dentate gyrus of the hippocampal formation chiefly from patients with schizophrenia or cognitive dysfunctions.

Histochemical characteristic of perivascular space in the brain with an advanced edema.

Amorphorous and colorless spaces, Virchow-Robin spaces (VRS), were often found by HE stain around blood vessels in the edematous brain. Histochemical characteristic of the enlarged VRS caused by an advanced edema and detected by lectin stain using Griffonia simplicifolia I agglutinin in the brain stem, the occipital lobe and/or the cerebellum was examined by means of immunohistochemical method. After pretreatment with formic acid or proteinase K, formalin fixed-paraffin embedded tissue sections were incubated with antibodies (ABs) against plasma proteins such as amyloid P component, Ig G, albumin (Al), apolipoprotein E (Apo E), and lactotransferrin (Lf), and cellular proteins such as ubiquitin (Ubt), Tau-protein (Tau), glial fibrillary acidic protein (GFAP), myelin basic protein (MBP), CD68 (KP-1) and heparansulfate proteoglycan (HSG). The tissue sections were also incubated with antibodies against alanyl aminopeptidase-S (AAP-S) and alanyl aminopeptidase-N (AAP-N) without pretreatment. The VRS showed intensive reactivity with ABs against Amy P, AAP-S and AAP-N, moderate with ABs against Apo E and HSG, weak with ABs against Ig G, Al and Lf, feeble with ABs against Ubt, Tau and CD 68, and no with ABs against GFAP and MBP, respectively. Although the substances detected in VRS might be of blood plasma origin resulting from abnormalities in the blood-brain barrier, the mechanisms whereby the serum proteins and/or other substances are enriched in VRS remain incompletely understood.