Hypertrophy of nigral neurons in Torsin1A deletion (DYT1) carriers manifesting dystonia.

OBJECTIVE: To individuate morphometric changes and prevalent types of intraneuronal inclusions in nigral neurons of DYT1 dystonia autopsy-brains. METHODS: Using precise methods of quantification, such as unbiased stereology, we measured cellular and subcellular volumes of neuromelanin-containing (pigmented) neurons in the substantia nigra (SN) of DYT1 carriers with and without manifestation of generalized dystonia (manif-DYT1 and non-manif-DYT1, respectively), non-DYT1 carriers manifesting generalized dystonia (manif-non-DYT1) patients, and age-matched control subjects (controls). A total of four DYT1 carriers (two manif-DYT1 and two non-manif-DYT1), six manif-non-DYT1 carriers, and six controls autopsy-brains were available for these neuropathological-morphometric analyses. The search of brain lesions was performed for: tau neurofibrillary tangles and neurites, extracellular ß-amyloid deposits, Lewy bodies and neurites, TorsinA, Laminin A + C, Ubiquitin, p62, pTDP43 intraneuronal inclusions; and Negri, Bunina, Hirano, Marinesco, Nissl, and Buscaino bodies. RESULTS: An increased mean cell body, nuclear, and nucleolar volume of nigral neurons in manif-DYT1 vs. non-manif-DYT1 (p < 0.0001), manif-non-DYT1 (p < 0.0001), and controls (p < 0.00001) was found. Increased nuclear and nucleolar volumes in manif-non-DYT1 vs. controls were also found. None of the considered possible intraneuronal lesions were more frequent or prevalent in nigral neurons of manif-DYT1 vs. all the other groups. CONCLUSIONS: Unbiased stereology-based measurements of nigral neurons enlargement in manif-DYT1 in the absence of intraneuronal inclusions or neurodegenerative processes, is novel. These findings suggest distinct pathogenetic mechanisms between manif-DYT1 vs. non-manif-DYT1 and manif-non-DYT1 dystonia, especially in terms of possible nigral dopaminergic abnormalities. These data could open new pathophysiologic views on specific dopamino-associated pathomechanisms related to the clinical manifestation of generalized dystonia.

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

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.

Parkinson disease and incidental Lewy body disease: Just a question of time?

OBJECTIVE: To quantify the loss of pigmented neurons in the substantia nigra (SN) of autopsy-confirmed Parkinson disease (PD) and incidental Lewy body disease (ILBD) vs age-matched controls (C). METHODS: Unbiased stereology methods were used to rigorously count number and measure volumes of nigral pigmented neurons in PD, ILBD, and C brains. The obtained stereologic results were correlated with Lewy body (LB), amyloid plaque (AP), neurofibrillary tangle (NFT), and vascular pathology loads assessed in nigral and extranigral regions of each PD, ILBD, and C brain. The stereologic measurements were also correlated to predeath motor and cognitive scores as available for each participant. RESULTS: A marked nigral neuronal loss (NNL) in PD (-82%) and ILBD (-40%) compared to C (p < 0.0001) was found. While there was significant correlation between NNL and LB in some cortical areas of PD (i.e., olfactory bulb), there were no correlations between NNL and LB, AP, or NFT loads or cerebral infarct volumes in any other examined regions for PD and ILBD brains. CONCLUSIONS: Using unbiased stereology methods, we show that there is a significant loss and absence of hypertrophic changes in nigral pigmented neurons of ILBD in comparison to C brains. Intriguingly, no significant correlations were found between NNL and LB loads in the SN of both PD and ILBD brains. These autopsy-verified stereologically based findings are novel and support ILBD as a pathologic condition. These results suggest possible new and alternative pathophysiologic hypotheses on the actual relationship between NNL and LB pathology.

Reduced Number of Pigmented Neurons in the Substantia Nigra of Dystonia Patients? Findings from Extensive Neuropathologic, Immunohistochemistry, and Quantitative Analyses.

BACKGROUND: Dystonias (Dys) represent the third most common movement disorder after essential tremor (ET) and Parkinson's disease (PD). While some pathogenetic mechanisms and genetic causes of Dys have been identified, little is known about their neuropathologic features. Previous neuropathologic studies have reported generically defined neuronal loss in various cerebral regions of Dys brains, mostly in the basal ganglia (BG), and specifically in the substantia nigra (SN). Enlarged pigmented neurons in the SN of Dys patients with and without specific genetic mutations (e.g., GAG deletions in DYT1 dystonia) have also been described. Whether or not Dys brains are associated with decreased numbers or other morphometric changes of specific neuronal types is unknown and has never been addressed with quantitative methodologies. METHODS: Quantitative immunohistochemistry protocols were used to estimate neuronal counts and volumes of nigral pigmented neurons in 13 SN of Dys patients and 13 SN of age-matched control subjects (C). RESULTS: We observed a significant reduction (∼20%) of pigmented neurons in the SN of Dys compared to C (p<0.01). Neither significant volumetric changes nor evident neurodegenerative signs were observed in the remaining pool of nigral pigmented neurons in Dys brains. These novel quantitative findings were confirmed after exclusion of possible co-occurring SN pathologies including Lewy pathology, tau-neurofibrillary tangles, ß-amyloid deposits, ubiquitin (ubiq), and phosphorylated-TAR DNA-binding protein 43 (pTDP43)-positive inclusions. DISCUSSION: A reduced number of nigral pigmented neurons in the absence of evident neurodegenerative signs in Dys brains could indicate previously unconsidered pathogenetic mechanisms of Dys such as neurodevelopmental defects in the SN.

Drug-induced hemolytic anemia and thrombocytopenia associated with alterations of cell membrane lipids and acanthocyte formation.

CXCR3 is a chemokine receptor, upregulated upon activation of T cells and expressed on nearly 100% of T cells in sites of inflammation. SCH 900875 is a selective CXCR3 receptor antagonist. Thrombocytopenia and severe hemolytic anemia with acanthocytosis occurred in rats at doses of 75, 100, and 150 mg/kg/day. Massively enlarged spleens corresponded histologically to extramedullary hematopoiesis, macrophages, and hemosiderin pigment and sinus congestion. Phagocytosed erythrocytes and platelets were within splenic macrophages. IgG and/or IgM were not detected on erythrocyte and platelet membranes. Ex vivo increased osmotic fragility of RBCs was observed. Lipid analysis of the RBC membrane revealed modifications in phosphatidylcholine, overall cholesterol, and/or sphingomyelin. Platelets exhibited slender filiform processes on their plasma membranes, analogous to those of acanthocytes. The presence of similar morphological abnormalities in acanthocytes and platelets suggests that possibly similar alterations in the lipid composition of the plasma membrane have taken place in both cell types. This phenotype correlated with alterations in plasma lipids (hypercholesterolemia and low triglycerides) that occurred after SCH 900875 administration, although other factors cannot be excluded. The increased cell destruction was considered triggered by alterations in the lipid profile of the plasma membranes of erythrocytes and platelets, as reflected morphologically.