Correlation of Presynaptic and Postsynaptic Proteins with Pathology in Alzheimer's Disease.

Synaptic transmission is essential for nervous system function and the loss of synapses is a known major contributor to dementia. Alzheimer's disease dementia (ADD) is characterized by synaptic loss in the mesial temporal lobe and cerebral neocortex, both of which are brain areas associated with memory and cognition. The association of synaptic loss and ADD was established in the late 1980s, and it has been estimated that 30-50% of neocortical synaptic protein is lost in ADD, but there has not yet been a quantitative profiling of different synaptic proteins in different brain regions in ADD from the same individuals. Very recently, positron emission tomography (PET) imaging of synapses is being developed, accelerating the focus on the role of synaptic loss in ADD and other conditions. In this study, we quantified the densities of two synaptic proteins, the presynaptic protein Synaptosome Associated Protein 25 (SNAP25) and the postsynaptic protein postsynaptic density protein 95 (PSD95) in the human brain, using enzyme-linked immunosorbent assays (ELISA). Protein was extracted from the cingulate gyrus, hippocampus, frontal, primary visual, and entorhinal cortex from cognitively unimpaired controls, subjects with mild cognitive impairment (MCI), and subjects with dementia that have different levels of Alzheimer's pathology. SNAP25 is significantly reduced in ADD when compared to controls in the frontal cortex, visual cortex, and cingulate, while the hippocampus showed a smaller, non-significant reduction, and entorhinal cortex concentrations were not different. In contrast, all brain areas showed lower PSD95 concentrations in ADD when compared to controls without dementia, although in the hippocampus, this failed to reach significance. Interestingly, cognitively unimpaired cases with high levels of AD pathology had higher levels of both synaptic proteins in all brain regions. SNAP25 and PSD95 concentrations significantly correlated with densities of neurofibrillary tangles, amyloid plaques, and Mini Mental State Examination (MMSE) scores. Our results suggest that synaptic transmission is affected by ADD in multiple brain regions. The differences were less marked in the entorhinal cortex and the hippocampus, most likely due to a ceiling effect imposed by the very early development of neurofibrillary tangles in older people in these brain regions.

Symmetry of synuclein density in autopsied Parkinson's disease submandibular glands.

BACKGROUND: Peripheral tissue biopsy in Parkinson's disease (PD) may be valuable for clinical care, biomarker validation, and as research enrollment criteria. OBJECTIVE: Determine whether submandibular gland pathologic alpha-synuclein (aSyn) density is symmetrical and whether previous needle biopsy caused tissue damage. METHODS: Thirty autopsy-confirmed PD cases having fixed submandibular gland tissue from one side and frozen submandibular gland tissue from the contralateral side were studied. Tissue was stained for phosphorylated aSyn and density (0-4 semiquantitative scale) was determined. Three previously biopsied cases were also assessed for tissue damage at subsequent autopsy. RESULTS: Mean (SD) age was 80.9 (5.5) years and disease duration 12.5 (9.3). Submandibular gland aSyn staining had a mean score of 2.13 for both the initially fixed and the initially frozen submandibular glands. The correlation between aSyn density of the two sides was r = 0.63. Correlation of aSyn density, in the originally fixed submandibular gland, with disease duration was good (r = 0.49, p =.006). No permanent tissue damage was found in the three previously biopsied cases. CONCLUSIONS: This study found good correlation between aSyn density in both submandibular glands of patients with PD and found no evidence of significant tissue damage in previously biopsied subjects.

Biochemical analyses of tau and other neuronal markers in the submandibular gland and frontal cortex across stages of Alzheimer disease.

Hyperphosphorylation of the microtubule-associated protein tau is hypothesized to lead to the development of neurofibrillary tangles in select brain regions during normal aging and in Alzheimer disease (AD). The distribution of neurofibrillary tangles is staged by its involvement starting in the transentorhinal regions of the brain and in final stages progress to neocortices. However, it has also been determined neurofibrillary tangles can extend into the spinal cord and select tau species are found in peripheral tissues and this may be depended on AD disease stage. To further understand the relationships of peripheral tissues to AD, we utilized biochemical methods to evaluate protein levels of total tau and phosphorylated tau (p-tau) as well as other neuronal proteins (i.e., tyrosine hydroxylase (TH), neurofilament heavy chain (NF-H), and microtubule-associated protein 2 (MAP2)) in the submandibular gland and frontal cortex of human cases across different clinicopathological stages of AD (n = 3 criteria not met or low, n = 6 intermediate, and n = 9 high likelihood that dementia is due to AD based on National Institute on Aging-Reagan criteria). We report differential protein levels based on the stage of AD, anatomic specific tau species, as well as differences in TH and NF-H. In addition, exploratory findings were made of the high molecular weight tau species big tau that is unique to peripheral tissues. Although sample sizes were small, these findings are, to our knowledge, the first comparison of these specific protein changes in these tissues.

Cerebral white matter rarefaction has both neurodegenerative and vascular causes and may primarily be a distal axonopathy.

Cerebral white matter rarefaction (CWMR) was considered by Binswanger and Alzheimer to be due to cerebral arteriolosclerosis. Renewed attention came with CT and MR brain imaging, and neuropathological studies finding a high rate of CWMR in Alzheimer disease (AD). The relative contributions of cerebrovascular disease and AD to CWMR are still uncertain. In 1181 autopsies by the Arizona Study of Aging and Neurodegenerative Disorders (AZSAND), large-format brain sections were used to grade CWMR and determine its vascular and neurodegenerative correlates. Almost all neurodegenerative diseases had more severe CWMR than the normal control group. Multivariable logistic regression models indicated that Braak neurofibrillary stage was the strongest predictor of CWMR, with additional independently significant predictors including age, cortical and diencephalic lacunar and microinfarcts, body mass index, and female sex. It appears that while AD and cerebrovascular pathology may be additive in causing CWMR, both may be solely capable of this. The typical periventricular pattern suggests that CWMR is primarily a distal axonopathy caused by dysfunction of the cell bodies of long-association corticocortical projection neurons. A consequence of these findings is that CWMR should not be viewed simply as "small vessel disease" or as a pathognomonic indicator of vascular cognitive impairment or vascular dementia.

Low clinical sensitivity and unexpectedly high incidence for neuropathologically diagnosed progressive supranuclear palsy.

The objective of this study was to determine the prevalence, incidence, and clinical diagnostic accuracy for neuropathologically diagnosed progressive supranuclear palsy (PSP) with data from a longitudinal clinicopathological study using Rainwater criteria to define neuropathological PSP. Of 954 autopsy cases, 101 met Rainwater criteria for the neuropathologic diagnosis of PSP. Of these, 87 were termed clinicopathological PSP as they also had either dementia or parkinsonism or both. The prevalence of clinicopathologically defined PSP subjects in the entire autopsy dataset was 9.1%, while the incidence rate was estimated at 780 per 100 000 persons per year, roughly 50-fold greater than most previous clinically determined PSP incidence estimates. A clinical diagnosis of PSP was 99.6% specific but only 9.2% sensitive based on first examination, and 99.3% specific and 20.7% sensitive based on the final clinical exam. Of the clinicopathologically defined PSP cases, 35/87 (∼40%) had no form of parkinsonism at first assessment, while this decreased to 18/83 (21.7%) at final assessment. Our study confirms a high specificity but low sensitivity for the clinical diagnosis of PSP. The low clinical sensitivity for PSP is likely primarily responsible for previous underestimates of the PSP population incidence rate.

Integrated DNA Methylation/RNA Profiling in Middle Temporal Gyrus of Alzheimer's Disease.

Alzheimer's disease is a neurodegenerative disorder clinically defined by gradual cognitive impairment and alteration in executive function. We conducted an epigenome-wide association study (EWAS) of a clinically and neuropathologically characterized cohort of 296 brains, including Alzheimer's disease (AD) and non-demented controls (ND), exploring the relationship with the RNA expression from matched donors. We detected 5246 CpGs and 832 regions differentially methylated, finding overlap with previous EWAS but also new associations. CpGs previously identified in ANK1, MYOC, and RHBDF2 were differentially methylated, and one of our top hits (GPR56) was not previously detected. ANK1 was differentially methylated at the region level, along with APOE and RHBDF2. Only a small number of genes showed a correlation between DNA methylation and RNA expression statistically significant. Multiblock partial least-squares discriminant analysis showed several CpG sites and RNAs discriminating AD and ND (AUC = 0.908) and strongly correlated with each other. Furthermore, the CpG site cg25038311 was negatively correlated with the expression of 22 genes. Finally, with the functional epigenetic module analysis, we identified a protein-protein network characterized by inverse RNA/DNA methylation correlation and enriched for "Regulation of insulin-like growth factor transport", with IGF1 as the hub gene. Our results confirm and extend the previous EWAS, providing new information about a brain region not previously explored in AD DNA methylation studies. The relationship between DNA methylation and gene expression is not significant for most of the genes in our sample, consistently with the complexities in the gene expression regulation.

SARS-CoV-2 Brain Regional Detection, Histopathology, Gene Expression, and Immunomodulatory Changes in Decedents with COVID-19.

Brains of 42 COVID-19 decedents and 107 non-COVID-19 controls were studied. RT-PCR screening of 16 regions from 20 COVID-19 autopsies found SARS-CoV-2 E gene viral sequences in 7 regions (2.5% of 320 samples), concentrated in 4/20 subjects (20%). Additional screening of olfactory bulb (OB), amygdala (AMY) and entorhinal area for E, N1, N2, RNA-dependent RNA polymerase, and S gene sequences detected one or more of these in OB in 8/21 subjects (38%). It is uncertain whether these RNA sequences represent viable virus. Significant histopathology was limited to 2/42 cases (4.8%), one with a large acute cerebral infarct and one with hemorrhagic encephalitis. Case-control RNAseq in OB and AMY found more than 5000 and 700 differentially expressed genes, respectively, unrelated to RT-PCR results; these involved immune response, neuronal constituents, and olfactory/taste receptor genes. Olfactory marker protein-1 reduction indicated COVID-19-related loss of OB olfactory mucosa afferents. Iba-1-immunoreactive microglia had reduced area fractions in cerebellar cortex and AMY, and cytokine arrays showed generalized downregulation in AMY and upregulation in blood serum in COVID-19 cases. Although OB is a major brain portal for SARS-CoV-2, COVID-19 brain changes are more likely due to blood-borne immune mediators and trans-synaptic gene expression changes arising from OB deafferentation.

Olfactory Bulb Amyloid-ß Correlates With Brain Thal Amyloid Phase and Severity of Cognitive Impairment.

The Alzheimer disease (AD) neuropathological hallmarks amyloid ß (Aß) and tau neurofibrillary (NF) pathology have been reported in the olfactory bulb (OB) in aging and in different neurodegenerative diseases, which coincides with frequently reported olfactory dysfunction in these conditions. To better understand when the OB is affected in relation to the hierarchical progression of Aß throughout the brain and whether OB pathology might be an indicator of AD severity, we assessed the presence of OB Aß and tau NF pathology in an autopsy cohort of 158 non demented control and 173 AD dementia cases. OB Aß was found in less than 5% of cases in lower Thal phases 0 and 1, in 20% of cases in phase 2, in 60% of cases in phase 3 and in more than 80% of cases in higher Thal phases 4 and 5. OB Aß and tau pathology significantly predicted a Thal phase greater than 3, a Braak NF stage greater than 4, and an MMSE score lower than 24. While OB tau pathology is almost universal in the elderly and therefore is not a good predictor of AD severity, OB Aß pathology coincides with clinically-manifest AD and might prove to be a useful biomarker of the extent of brain spread of both amyloid and tau pathology.

Effect of olfactory bulb pathology on olfactory function in normal aging.

Decline of olfactory function is frequently observed in aging and is an early symptom of neurodegenerative diseases. As the olfactory bulb (OB) is one of the first regions involved by pathology and may represent an early disease stage, we specifically aimed to evaluate the contribution of OB pathology to olfactory decline in cognitively normal aged individuals without parkinsonism or dementia. This clinicopathological study correlates OB tau, amyloid ß (Aß) and α-synuclein (αSyn) pathology densities and whole brain pathology load to olfactory identification function as measured with the University of Pennsylvania Smell Identification Test (UPSIT) and clinical data measured proximate to death in a large autopsy study including 138 cases considered non-demented controls during life. Tau pathology was frequently observed in the OB (95% of cases), while both Aß (27% of cases) and αSyn (20% of cases) OB pathologies were less commonly observed. A weak correlation was only observed between OB tau and olfactory performance, but when controlled for age, neither OB tau, Aß or αSyn significantly predict olfactory performance. Moreover, whole brain tau and αSyn pathology loads predicted olfactory performance; however, only αSyn pathology loads survived age correction. In conclusion, OB tau pathology is frequently observed in normally aging individuals and increases with age but does not appear to independently contribute to age-related olfactory impairment suggesting that further involvement of the brain seems necessary to contribute to age-related olfactory decline.

Hemispheric Asymmetry and Atypical Lobar Progression of Alzheimer-Type Tauopathy.

The spread of neurofibrillary tau pathology in Alzheimer disease (AD) mostly follows a stereotypical pattern of topographical progression but atypical patterns associated with interhemispheric asymmetry have been described. Because histopathological studies that used bilateral sampling are limited, this study aimed to assess interhemispheric tau pathology differences and the presence of topographically atypical cortical spreading patterns. Immunohistochemical staining for detection of tau pathology was performed in 23 regions of interest in 57 autopsy cases comparing bilateral cortical regions and hemispheres. Frequent mild (82% of cases) and occasional moderate (32%) interhemispheric density discrepancies were observed, whereas marked discrepancies were uncommon (7%) and restricted to occipital regions. Left and right hemispheric tau pathology dominance was observed with similar frequencies, except in Braak Stage VI that favored a left dominance. Interhemispheric Braak stage differences were observed in 16% of cases and were more frequent in advanced (IV-VI) versus early (I-III) stages. One atypical lobar topographical pattern in which occipital tau pathology density exceeded frontal lobe scores was identified in 4 cases favoring a left dominant asymmetry. We speculate that asymmetry and atypical topographical progression patterns may be associated with atypical AD clinical presentations and progression characteristics, which should be tested by comprehensive clinicopathological correlations.

Olfactory Dysfunction in Incidental Lewy Body Disease and Parkinson's Disease: An Update.

Objective: Measuring olfactory dysfunction shows promise as one of a number of nonmotor biomarkers that can be used to detect clinically manifest and prodromal Parkinson's disease (PD) and dementia with Lewy bodies (DLB) and to differentiate these from nonsynucleinopathies. Using a larger sample size than in our previous study, we evaluated the relationship between olfactory dysfunction based on the University of Pennsylvania Smell Identification Test (UPSIT) to the clinicopathological findings in patients with PD (n=41), patients with incidental Lewy body disease (ILBD) (n=47), and controls with no neurodegenerative disease (n=137). Design: This study was conducted through the Arizona Study of Aging and Neurodegenerative Disease (AZSAND). We selected individuals who had an UPSIT score completed antemortem and were clinicopathologically diagnosed with PD, ILBD, or control. Various measures included density of Lewy type synucleinopathy (aSyn) in the olfactory bulb and tract, as well as connected mesial temporal lobe structures. Cases and controls were analyzed using one-way analysis of variance (ANOVA) with pairwise contrasts. Results: Compared to controls (mean: 27.8, standard deviation [SD]: 6.0), the mean UPSIT scores were lower for PD (15.8, SD: 6.0, p<0.001) and ILBD (24.1, SD: 8.6, p<0.001). The sensitivity for detecting ILBD from controls, based on a cutoff score of less than 23 (23/47), was 48.9 percent. The specificity for detecting a control was 79.6 percent with a cutoff greater than 23 (109/137). Conclusion: These findings replicate, with a larger sample size, our previously published findings that individuals with autopsy-confirmed PD and ILBD have significantly lower UPSIT scores compared to controls. These data add to the growing body of evidence supporting early olfactory dysfunction as a prodromal biomarker for the risk of developing PD and ILBD as a prodromal Lewy body disorder.

Clinical Diagnostic Accuracy of Early/Advanced Parkinson Disease: An Updated Clinicopathologic Study.

OBJECTIVE: To update data for diagnostic accuracy of a clinical diagnosis of Parkinson disease (PD) using neuropathologic diagnosis as the gold standard. METHODS: Data from the Arizona Study of Aging and Neurodegenerative Disorders (AZSAND) were used to determine the predictive value of a clinical PD diagnosis. Two clinical diagnostic confidence levels were used, possible PD (PossPD, never treated or not responsive) and probable PD (ProbPD, 2/3 cardinal clinical signs and responsive to dopaminergic medications). Neuropathologic diagnosis was the gold standard. RESULTS: Based on the first visit to AZSAND, 15/54 (27.8%) PossPD participants and 138/163 (84.7%) ProbPD participants had confirmed PD. PD was confirmed in 24/34 (70.6%) ProbPD with <5 years and 114/128 (89.1%) with ≥5 years disease duration. Using the consensus final clinical diagnosis following death, 161/187 (86.1%) ProbPD had neuropathologically confirmed PD. Diagnostic accuracy for ProbPD improved if included motor fluctuations, dyskinesias, and hyposmia, and hyposmia for PossPD. CONCLUSIONS: This updated study confirmed lower clinical diagnostic accuracy for elderly, untreated or poorly responsive PossPD participants and for ProbPD with <5 years of disease duration, even when medication responsive. Caution continues to be needed when interpreting clinical studies of PD, especially studies of early disease, that do not have autopsy confirmation. CLASSIFICATION OF EVIDENCE: This study provides Class II evidence that a clinical diagnosis of ProbPD at the first visit identifies participants who will have pathologically confirmed PD with a sensitivity of 82.6% and a specificity of 86.0%.

Olfactory Bulb and Amygdala Gene Expression Changes in Subjects Dying with COVID-19.

In this study we conducted RNA sequencing on two brain regions (olfactory bulb and amygdala) from subjects who died from COVID-19 or who died of other causes. We found several-fold more transcriptional changes in the olfactory bulb than in the amygdala, consistent with our own work and that of others indicating that the olfactory bulb may be the initial and most common brain region infected. To some extent our results converge with pseudotime analysis towards common processes shared between the brain regions, possibly induced by the systemic immune reaction following SARS-CoV-2 infection. Changes in amygdala emphasized upregulation of interferon-related neuroinflammation genes, as well as downregulation of synaptic and other neuronal genes, and may represent the substrate of reported acute and subacute COVID-19 neurological effects. Additionally, and only in olfactory bulb, we observed an increase in angiogenesis and platelet activation genes, possibly associated with microvascular damages induced by neuroinflammation. Through coexpression analysis we identified two key genes (CAMK2B for the synaptic neuronal network and COL1A2 for the angiogenesis/platelet network) that might be interesting potential targets to reverse the effects induced by SARS-CoV-2 infection. Finally, in olfactory bulb we detected an upregulation of olfactory and taste genes, possibly as a compensatory response to functional deafferentation caused by viral entry into primary olfactory sensory neurons. In conclusion, we were able to identify transcriptional profiles and key genes involved in neuroinflammation, neuronal reaction and olfaction induced by direct CNS infection and/or the systemic immune response to SARS-CoV-2 infection.

Vagus Nerve and Stomach Synucleinopathy in Parkinson's Disease, Incidental Lewy Body Disease, and Normal Elderly Subjects: Evidence Against the "Body-First" Hypothesis.

BACKGROUND: Braak and others have proposed that Lewy-type α-synucleinopathy in Parkinson's disease (PD) may arise from an exogenous pathogen that passes across the gastric mucosa and then is retrogradely transported up the vagus nerve to the medulla. OBJECTIVE: We tested this hypothesis by immunohistochemically staining, with a method specific for p-serine 129 α-synuclein (pSyn), stomach and vagus nerve tissue from an autopsy series of 111 normal elderly subjects, 33 with incidental Lewy body disease (ILBD) and 53 with PD. METHODS: Vagus nerve samples were taken adjacent to the carotid artery in the neck. Stomach samples were taken from the gastric body, midway along the greater curvature. Formalin-fixed paraffin-embedded sections were immunohistochemically stained for pSyn, shown to be highly specific and sensitive for α-synuclein pathology. RESULTS: Median disease duration for the PD group was 13 years. In the vagus nerve none of the 111 normal subjects had pSyn in the vagus, while 12/26 ILBD (46%) and 32/36 PD (89%) subjects were pSyn-positive. In the stomach none of the 102 normal subjects had pSyn while 5/30 (17%) ILBD and 42/52 (81%) of PD subjects were pSyn-positive. CONCLUSION: As there was no pSyn in the vagus nerve or stomach of subjects without brain pSyn, these results support initiation of pSyn in the brain. The presence of pSyn in the vagus nerve and stomach of a subset of ILBD cases indicates that synucleinopathy within the peripheral nervous system may occur, within a subset of individuals, at preclinical stages of Lewy body disease.

Acute Brain Ischemia, Infarction and Hemorrhage in Subjects Dying with or Without Autopsy-Proven Acute Pneumonia.

Stroke is one of the most serious complications of Covid-19 disease but it is still unclear whether stroke is more common with Covid-19 pneumonia as compared to non-Covid-19 pneumonia. We investigated the concurrence rate of autopsy-confirmed acute brain ischemia, acute brain infarction and acute brain hemorrhage with autopsy-proven acute non-Covid pneumonia in consecutive autopsies in the Arizona Study of Aging and Neurodegenerative Disorders (AZSAND), a longitudinal clinicopathological study of normal aging and neurodegenerative diseases. Of 691 subjects with a mean age of 83.4 years, acute pneumonia was histopathologically diagnosed in 343 (49.6%); the concurrence rates for histopathologically-confirmed acute ischemia, acute infarction or subacute infarction was 14% and did not differ between pneumonia and non-pneumonia groups while the rates of acute brain hemorrhage were 1.4% and 2.0% of those with or without acute pneumonia, respectively. In comparison, in reviews of Covid-19 publications, reported clinically-determined rates of acute brain infarction range from 0.5% to 20% while rates of acute brain hemorrhage range from 0.13% to 2%. In reviews of Covid-19 autopsy studies, concurrence rates for both acute brain infarction and acute brain hemorrhage average about 10%. Covid-19 pneumonia and non-Covid-19 pneumonia may have similar risks tor concurrent acute brain infarction and acute brain hemorrhage when pneumonia is severe enough to cause death. Additionally, acute brain ischemia, infarction or hemorrhage may not be more common in subjects dying of acute pneumonia than in subjects dying without acute pneumonia.

Clinicopathological Correlation: Dopamine and Amyloid PET Imaging with Neuropathology in Three Subjects Clinically Diagnosed with Alzheimer's Disease or Dementia with Lewy Bodies.

BACKGROUND: Imaging biomarkers have the potential to distinguish between different brain pathologies based on the type of ligand used with PET. AV-45 PET (florbetapir, Amyvid™) is selective for the neuritic plaque amyloid of Alzheimer's disease (AD), while AV-133 PET (florbenazine) is selective for VMAT2, which is a dopaminergic marker. OBJECTIVE: To report the clinical, AV-133 PET, AV-45 PET, and neuropathological findings of three clinically diagnosed dementia patients who were part of the Avid Radiopharmaceuticals AV133-B03 study as well as the Arizona Study of Aging and Neurodegenerative Disorders (AZSAND). METHODS: Three subjects who had PET imaging with both AV-133 and AV-45 as well as a standardized neuropathological assessment were included. The final clinical, PET scan, and neuropathological diagnoses were compared. RESULTS: The clinical and neuropathological diagnoses were made blinded to PET scan results. The first subject had a clinical diagnosis of dementia with Lewy bodies (DLB); AV-133 PET showed bilateral striatal dopaminergic degeneration, and AV-45 PET was positive for amyloid. The final clinicopathological diagnosis was DLB and AD. The second subject was diagnosed clinically with probable AD; AV-45 PET was positive for amyloid, while striatal AV-133 PET was normal. The final clinicopathological diagnosis was DLB and AD. The third subject had a clinical diagnosis of DLB. Her AV-45 PET was positive for amyloid and striatal AV-133 showed dopaminergic degeneration. The final clinicopathological diagnosis was multiple system atrophy and AD. CONCLUSION: PET imaging using AV-133 for the assessment of striatal VMAT2 density may help distinguish between AD and DLB. However, some cases of DLB with less-pronounced nigrostriatal dopaminergic neuronal loss may be missed.

Mapping of SARS-CoV-2 Brain Invasion and Histopathology in COVID-19 Disease.

The coronavirus SARS-CoV-2 (SCV2) causes acute respiratory distress, termed COVID-19 disease, with substantial morbidity and mortality. As SCV2 is related to previously-studied coronaviruses that have been shown to have the capability for brain invasion, it seems likely that SCV2 may be able to do so as well. To date, although there have been many clinical and autopsy-based reports that describe a broad range of SCV2-associated neurological conditions, it is unclear what fraction of these have been due to direct CNS invasion versus indirect effects caused by systemic reactions to critical illness. Still critically lacking is a comprehensive tissue-based survey of the CNS presence and specific neuropathology of SCV2 in humans. We conducted an extensive neuroanatomical survey of RT-PCR-detected SCV2 in 16 brain regions from 20 subjects who died of COVID-19 disease. Targeted areas were those with cranial nerve nuclei, including the olfactory bulb, medullary dorsal motor nucleus of the vagus nerve and the pontine trigeminal nerve nuclei, as well as areas possibly exposed to hematogenous entry, including the choroid plexus, leptomeninges, median eminence of the hypothalamus and area postrema of the medulla. Subjects ranged in age from 38 to 97 (mean 77) with 9 females and 11 males. Most subjects had typical age-related neuropathological findings. Two subjects had severe neuropathology, one with a large acute cerebral infarction and one with hemorrhagic encephalitis, that was unequivocally related to their COVID-19 disease while most of the 18 other subjects had non-specific histopathology including focal ß-amyloid precursor protein white matter immunoreactivity and sparse perivascular mononuclear cell cuffing. Four subjects (20%) had SCV2 RNA in one or more brain regions including the olfactory bulb, amygdala, entorhinal area, temporal and frontal neocortex, dorsal medulla and leptomeninges. The subject with encephalitis was SCV2-positive in a histopathologically-affected area, the entorhinal cortex, while the subject with the large acute cerebral infarct was SCV2-negative in all brain regions. Like other human coronaviruses, SCV2 can inflict acute neuropathology in susceptible patients. Much remains to be understood, including what viral and host factors influence SCV2 brain invasion and whether it is cleared from the brain subsequent to the acute illness.

Vascular Lesions, APOE ε4, and Tau Pathology in Alzheimer Disease.

We sought to determine the associations among cerebral amyloid angiopathy (CAA), white matter rarefaction (WMR), circle of Willis atherosclerosis (CWA), and total microinfarct number with Braak neurofibrillary stage in postmortem individuals with and without Alzheimer disease (AD). Data from 355 cases of autopsied individuals with Braak stage I-VI who had antemortem consensus diagnoses of cognitively unimpaired (n = 183), amnestic mild cognitive impairment (n = 31), and AD dementia (n = 141) were used. The association between Braak stage and vascular lesions were individually assessed using multivariable linear regression that adjusted for age at death, APOE ε4 carrier status, sex, education, and neuritic plaque density. CAA (p = 0.007) and WMR (p < 0.001) were associated with Braak stage, independent of amyloid load; microinfarct number and CWA showed no association. Analyses of the interactions between APOE ε4 carrier status and vascular lesions found that greater WMR and positive ε4 carrier status were associated with higher Braak stages. These results suggest that CAA and WMR are statistically linked to the severity of AD-related NFT pathology. The statistical link between WMR and NFT load may be strengthened by the presence of APOE ε4 carrier status. An additional finding was that Lewy body pathology was most prevalent in higher Braak stages.

Increased Risk of Autopsy-Proven Pneumonia with Sex, Season and Neurodegenerative Disease.

There has been a markedly renewed interest in factors associated with pneumonia, a leading cause of death worldwide, due to its frequent concurrence with pandemics of influenza and Covid-19 disease. Reported predisposing factors to both bacterial pneumonia and pandemic viral lower respiratory infections are wintertime occurrence, older age, obesity, pre-existing cardiopulmonary conditions and diabetes. Also implicated are age-related neurodegenerative diseases that cause parkinsonism and dementia. We investigated the prevalence of autopsy-proven pneumonia in the Arizona Study of Aging and Neurodegenerative Disorders (AZSAND), a longitudinal clinicopathological study, between the years 2006 and 2019 and before the beginning of the Covid-19 pandemic. Of 691 subjects dying at advanced ages (mean 83.4), pneumonia was diagnosed postmortem in 343 (49.6%). There were 185 subjects without dementia or parkinsonism while clinicopathological diagnoses for the other subjects included 319 with Alzheimer's disease dementia, 127 with idiopathic Parkinson's disease, 72 with dementia with Lewy bodies, 49 with progressive supranuclear palsy and 78 with vascular dementia. Subjects with one or more of these neurodegenerative diseases all had higher pneumonia rates, ranging between 50 and 61%, as compared to those without dementia or parkinsonism (40%). In multivariable logistic regression models, male sex and a non-summer death both had independent contributions (ORs of 1.67 and 1.53) towards the presence of pneumonia at autopsy while the absence of parkinsonism or dementia was a significant negative predictor of pneumonia (OR 0.54). Male sex, dementia and parkinsonism may also be risk factors for Covid-19 pneumonia. The apolipoprotein E4 allele, as well as obesity, chronic obstructive pulmonary disease, diabetes, hypertension, congestive heart failure, cardiomegaly and cigarette smoking history, were not significantly associated with pneumonia, in contradistinction to what has been reported for Covid-19 disease.

Human Autopsy-Derived Scalp Fibroblast Biobanking for Age-Related Neurodegenerative Disease Research.

The Arizona Study of Aging and Neurodegenerative Disorders/Brain and Body Donation Program at Banner Sun Health Research Institute (BSHRI) is a longitudinal clinicopathological study with a current enrollment of more than 900 living subjects for aging and neurodegenerative disease research. Annual clinical assessments are done by cognitive and movement neurologists and neuropsychologists. Brain and body tissues are collected at a median postmortem interval of 3.0 h for neuropathological diagnosis and banking. Since 2018, the program has undertaken banking of scalp fibroblasts derived from neuropathologically characterized donors with Alzheimer's disease, Parkinson's disease, and other neurodegenerative diseases. Here, we describe the procedure development and cell characteristics from 14 male and 15 female donors (mean ± SD of age: 83.6 ± 12.2). Fibroblasts from explant cultures were banked at passage 3. The results of mRNA analysis showed positive expression of fibroblast activation protein, vimentin, fibronectin, and THY1 cell surface antigen. We also demonstrated that the banked fibroblasts from a postmortem elderly donor were successfully reprogramed to human-induced pluripotent stem cells (hiPSCs). Taken together, we have demonstrated the successful establishment of a human autopsy-derived fibroblast banking program. The cryogenically preserved cells are available for request at the program website of the BSHRI.