Alzheimer’s disease (AD), the most prevalent neurodegenerative disorder, is characterized by executive dysfunction and memory impairment mediated by the accumulation of extracellular amyloid-β peptide (Aβ) and intracellular hyperphosphorylated tau protein. The hippocampus (HIPP) is essential for memory formation and is involved in early stages of disease. In fact, hippocampal atrophy is used as an early biomarker of neuronal injury and to evaluate disease progression. It is not yet well-understood whether changes in hippocampal volume are due to neuronal or glial loss. The aim of the study was to assess hippocampal atrophy and/or gliosis using unbiased stereological quantification and to obtain hippocampal proteomic profiles related to neurodegeneration and gliosis. Hippocampal volume measurement, stereological quantification of NeuN-, Iba-1- and GFAP-positive cells, and sequential window acquisition of all theoretical mass spectrometry (SWATH-MS) analysis were performed in AD and non-AD cases. Reduced hippocampal volume was identified using the Cavalieri probe, particularly in the CA1 region, where it correlated with neuronal loss and astrogliosis. A total of 102 downregulated and 47 upregulated proteins were identified in the SWATH-MS analysis after restrictive filtering based on an FC > 1.5 and p value < 0.01. The Hsp90 family of chaperones, particularly BAG3 and HSP90AB1, are closely related to astrocytes, indicating a possible role in degrading Aβ and tau through chaperone-mediated autophagy.

Alzheimer's disease (AD) is characterized by the accumulation of pathological amyloid‐β (Aβ) and Tau proteins. According to the prion‐like hypothesis, both proteins can seed and disseminate through brain regions through neural connections and glial cells. The amygdaloid complex (AC) is involved early in the disease, and its widespread connections with other brain regions indicate that it is a hub for propagating pathology. To characterize changes in the AC as well as the involvement of neuronal and glial cells in AD, a combined stereological and proteomic analysis was performed in non‐Alzheimer's disease and AD human samples. The synaptic alterations identified by proteomic data analysis could be related to the volume reduction observed in AD by the Cavalieri probe without neuronal loss. The pathological markers appeared in a gradient pattern with the medial region (cortical nucleus, Co) being more affected than lateral regions, suggesting the relevance of connections in the distribution of the pathology among different brain regions. Generalized astrogliosis was observed in every AC nucleus, likely related to deposits of pathological proteins. Astrocytes might mediate phagocytic microglial activation, whereas microglia might play a dual role since protective and toxic phenotypes have been described. These results highlight the potential participation of the amygdala in the disease spreading from/to olfactory areas, the temporal lobe and beyond. Proteomic data are available via ProteomeXchange with identifier PXD038322.

α-Synuclein, a protein mostly present in presynaptic terminals, accumulates neuropathologically in Parkinson's disease in a 6-stage sequence and propagates in the nervous system in a prion-like manner through neurons and glia. In stage 3, the substantia nigra are affected, provoking motor symptoms and the amygdaloid complex, leading to different nonmotor symptoms; from here, synucleinopathy spreads to the temporal cortex and beyond. The expected increase in Parkinson's disease incidence accelerates the need for detection biomarkers; however, the heterogeneity of this disease, including pathological aggregates and pathophysiological pathways, poses a challenge in the search for new therapeutic targets and biomarkers. Proteomic analyses are lacking, and the literature regarding synucleinopathy, neural and glial involvement, and volume of the human amygdaloid complex is controversial. Therefore, the present study combines both proteomic and stereological probes. Data-independent acquisition-parallel accumulation of serial fragmentation proteomic analysis revealed a remarkable proteomic impact, especially at the synaptic level in the human amygdaloid complex in Parkinson's disease. Among the 199 differentially expressed proteins, guanine nucleotide-binding protein G(i) subunit alpha-1 (GNAI1), elongation factor 1-alpha 1 (EEF1A1), myelin proteolipid protein (PLP1), neuroplastin (NPTN), 14-3-3 protein eta (YWHAH), gene associated with retinoic and interferon-induced mortality 19 protein (GRIM19), and orosomucoid-2 (ORM2) stand out as potential biomarkers in Parkinson's disease. Stereological analysis, however, did not reveal alterations regarding synucleinopathy, neural or glial populations, or volume changes. To our knowledge, this is the first proteomic study of the human amygdaloid complex in Parkinson's disease, and it identified possible biomarkers of the disease. Lewy pathology could not be sufficient to cause neurodegeneration or alteration of microglial and astroglial populations in the human amygdaloid complex in Parkinson's disease. Nevertheless, damage at the proteomic level is manifest, showing up significant synaptic involvement.

Alzheimer's disease (AD) includes amyloid-β plaques and tau tangles as associated proteinopathies. Tau aggregates appear in a sequential and predictable manner, defined by six stages (Braak stages I-VI) of neuropathological diagnosis, with the hippocampus, particularly the CA1 subfield, being involved in the early stages. Chaperones play a key role in amyloid-β and tau misfolding. Chaperones constitute a vast family of proteins, but proteomic assays have indicated that HSP90AA1, HSP90AB1 and BAG3 are differentially expressed in the hippocampus of human AD patients. However, it is unknown whether the distribution of these proteins changes across different hippocampal subfields and/or in different neuropathological stages. Therefore, the distributions of the HSP90AA1, HSP90AB1 and BAG3 chaperones across hippocampal subfields (CA1, CA2, CA3 and DG) and across neuropathological stages (non-AD, 0; initial-AD, I-I; intermediate-AD, III-IV; and advanced-AD, V-VI) were stereologically quantified using the Area Fraction Fractionator probe. The area fraction of HSP90AA1 was lower in CA1 in advanced stages, whereas that of HSP90AB1 was greater in CA2 in advanced stages. In contrast, the area fraction of BAG3 was greater in CA1, CA3 and the DG between the non-AD and initial-AD stages but was lower in the DG in the intermediate-AD stage. This finding suggests that chaperone dysregulation could be responsible for the altered clearance and increased pathological misfolding that is observed in AD, leading to differential subfield vulnerability. Indeed, these chaperones could be useful as predictive biomarkers or therapeutic targets for AD because of their differential distribution across subfields and stages, which may increase the sensitivity and specificity of these proteins for use in these ways.

Alzheimer’s disease (AD) is the most prevalent neurodegenerative disease in the elderly. Progressive accumulation of insoluble isoforms of amyloid-β peptide (Aβ) and tau protein are the major neuropathologic hallmarks, and the loss of cholinergic pathways underlies cognitive deficits in patients. Recently, glial involvement has gained interest regarding its effect on preservation and impairment of brain integrity. The limbic system, including temporal lobe regions and the olfactory bulb, is particularly affected in the early stages. In the early 1980s, the reduced expression of the somatostatin neuropeptide was described in AD. However, over the last three decades, research on somatostatin in Alzheimer’s disease has been scarce in humans. Therefore, the aim of this study was to stereologically quantify the expression of somatostatin in the human hippocampus and olfactory bulb and analyze its spatial distribution with respect to that of Aβ and au neuropathologic proteins and astroglia. The results indicate that somatostatin-expressing cells are reduced by 50% in the hippocampus but are preserved in the olfactory bulb. Interestingly, the coexpression of somatostatin with the Aβ peptide is very common but not with the tau protein. Finally, the coexpression of somatostatin with astrocytes is rare, although their spatial distribution is very similar. Altogether, we can conclude that somatostatin expression is highly reduced in the human hippocampus, but not the olfactory bulb, and may play a role in Alzheimer’s disease pathogenesis.

Background: Dissection and examination of prosected cadavers is a tool for teaching anatomy. However, this experience can provoke anxiety and stress among students. This study aims to understand the attitudes, reactions, fears, and anxiety states of podiatry students before their first dissection in addition to evaluate its usefulness as an educational tool for academic training in anatomy.Methods: A cross‐sectional study was carried out before and after the dissection room visit of first‐year podiatry students. They were given several questionnaires: State‐Trait Anxiety Inventory questionnaires (STAI‐state anxiety and STAI‐trait anxiety) and two anonymous questionnaires.Results: Levels of total emotional anxiety (STAI‐state anxiety) decreased significantly (p < 0.05) from 16.9 points before practice to 10.9 points after practice. In terms of gender, significant differences (p < 0.05) were observed in anxiety levels before and after practice. However, female students had significantly (p < 0.05) higher pre‐practice levels of STAI‐state anxiety than male students.Conclusions: Although 100% of students (3.98 ± 0.149, over 4) expressed satisfaction with the practical's dissection and considered that these contributed significantly to the consolidation of their anatomical knowledge, the experience generated emotional responses that need to be addressed. Higher levels of anxiety were observed among female students, highlighting the need to implement effective coping mechanisms to mitigate emotional reactions, with special emphasis on this population.