Symmetric Bihemispheric Postmortem Brain Cutting to Study Healthy and Pathological Brain Conditions in Humans

Summary

Organized brain cutting procedures are necessary to correlate specific neuropsychiatric phenomena with definitive neuropathologic diagnoses. Brain cuttings are performed differently based on various clinico-academic contingencies. This protocol describes a symmetric bihemispheric brain cutting procedure to investigate hemispheric differences in human brain pathologies and to maximize current and future biomolecular/neuroimaging techniques.

Abstract

Neuropathologists, at times, feel intimidated by the amount of knowledge needed to generate definitive diagnoses for complex neuropsychiatric phenomena described in those patients for whom a brain autopsy has been requested. Although the advancements of biomedical sciences and neuroimaging have revolutionized the neuropsychiatric field, they have also generated the misleading idea that brain autopsies have only a confirmatory value. This false idea created a drastic reduction of autopsy rates and, consequently, a reduced possibility to perform more detailed and extensive neuropathological investigations, which are necessary to comprehend numerous normal and pathological aspects yet unknown of the human brain. The traditional inferential method of correlation between observed neuropsychiatric phenomena and corresponding localization/characterization of their possible neurohistological correlates continues to have an undeniable value. In the context of neuropsychiatric diseases, the traditional clinicopathological method is still the best possible methodology (and often the only available) to link unique neuropsychiatric features to their corresponding neuropathological substrates, since it relies specifically upon the direct physical assessment of brain tissues. The assessment of postmortem brains is based on brain cutting procedures that vary across different neuropathology centers. Brain cuttings are performed in a relatively extensive and systematic way based on the various clinical and academic contingencies present in each institution. A more anatomically inclusive and symmetric bi-hemispheric brain cutting methodology should at least be used for research purposes in human neuropathology to coherently investigate, in depth, normal and pathological conditions with the peculiarities of the human brain (i.e., hemispheric specialization and lateralization for specific functions). Such a method would provide a more comprehensive collection of neuropathologically well-characterized brains available for current and future biotechnological and neuroimaging techniques. We describe a symmetric bi-hemispheric brain cutting procedure for the investigation of hemispheric differences in human brain pathologies and for use with current as well as future biomolecular/neuroimaging techniques.

Introduction

Neuropathologists have the scientific privilege, intellectual honor, and diagnostic obligation to assess human brains. For many decades, detailed clinical descriptions of brain diseases and major efforts to individuate their possible neurohistological correlates in human postmortem brains have been undertaken. Historically, those efforts represented the most productive modality by which the medical sciences, and neurology in particular, advanced in the modern era. Thanks to previous eminent neuropathologists and their dedication, determination, scholarship, and astonishing capacity to discriminate between normal and abnormal brain tissues (often using very rudimental ....

Protocol

Procedures involving postmortem human tissues have been reviewed by the institutional review board and exempted under 45 CFR (Code of Federal Regulations).

NOTE: The protocol describes a symmetric bihemispheric brain cutting procedure for postmortem brain assessment finalized for neuropathological studies in humans. Detailed descriptions of the apparatuses, instruments, materials, and supplies necessary to perform human brain cutting will be excluded. Materials and supplies for brain dissections are selected at the discretion of the single investigator and are based on autopsy tools allowed or approved at each research institution. The minimal set of tools and material required for....

Results

Protocol Length

The time spent for a single symmetric bihemispheric fixed brain cutting procedure is estimated at 1 h (excluding the time spent setting up the dissection table, tools, and cutting surfaces; labeling; etc.). The time required for a single symmetric bi-hemispheric alternating frozen and fixed brain cutting procedure is estimated to take 2 h. It can take at least between 4 - 6 weeks to obtain definitive histol.......

Discussion

This brain cutting method can be adapted to the specific needs of each neuropathology lab (for example, by reducing the number of cerebral regions to assess for each hemisphere) while still retaining the bihemispheric symmetric cutting procedure as one of its main features. This proposed protocol could be used for routine procedures (research-oriented neuropathological centers) or only when necessary (specific clinically oriented studies). It can be selectively used only for specific types of investigations (i.e.,

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
Copy of signed informed consent allowing autopsy and brain donation for research use.
Detailed clinical history of the subject which should include a detailed description of any neurologic and psychiatric symptoms and signs.
Medical or nonmedical video-recordings when available (especially useful in movement disorders field). Next-of-kin’s consent required.
Neuroimaging, neurophysiology, neuropsychiatric and assessment or clinicometric scales.
Genetic and family history data. Genetic reports review, if neurogenetic diseases were diagnosed.
Histology Container	ELECTRON MICROSCOPY SCIENCES	64233-24
Histology Cassettes	VWR	18000-142 (orange)
Histology Cassettes	VWR	18000-132 (navy)
Knife Handles and Disposable Blades	ELECTRON MICROSCOPY SCIENCES	62560-04
Long Blades	ELECTRON MICROSCOPY SCIENCES	62561-20
Disposable Blade Knife Handles	ELECTRON MICROSCOPY SCIENCES	72040-08
Scalpel Blades	ELECTRON MICROSCOPY SCIENCES	72049-22
Accu-Punch 2 mm	ELECTRON MICROSCOPY SCIENCES	69038-02
Polystyrene Containers – Sterile	ELECTRON MICROSCOPY SCIENCES	64240-12
Dissecting Board	ELECTRON MICROSCOPY SCIENCES	63307-30
Formalin solution, neutral buffered, 10%	Sigma-Aldrich	HT501128 SIGMA
Hematoxylin Solution, Gill No. 2	Sigma-Aldrich	GHS280 SIGMA
Eosin Y solution, aqueous	Sigma-Aldrich	HT1102128 SIGMA
anti-beta-amyloid	Covance, Princeton, NJ	SIG-39220	1:500
anti-tau	Thermo Fisher Scientific	MN1020	1:500
anti-alpha-synuclein	Abcam	ab27766	1:500
anti-phospho-TDP43	Cosmo Bio Co.	TIP-PTD-P02	1:2000
Digital Camera	Any
Head Impulse Sealing machine	Grainger	5ZZ35