Multiple system atrophy with amyloid-β-predominant Alzheimer's disease neuropathologic change

Multiple system atrophy is a neurodegenerative disease with α-synuclein pathology predominating in the striatonigral and olivopontocerebellar systems. Mixed pathologies are considered to be of low frequency and mostly comprise primary age-related tauopathy or low levels of Alzheimer's disease-related neuropathologic change. Therefore, the concomitant presence of different misfolded proteins in the same brain region is less likely in multiple system atrophy. During the neuropathological evaluation of 21 consecutive multiple system atrophy cases, we identified four cases exhibiting an unusual discrepancy between high Thal amyloid-β phase and low transentorhinal Braak neurofibrillary tangle stage. We mapped α-synuclein pathology, measured the size and number of glial cytoplasmic inclusions and compared the amyloid-β peptides between multiple system atrophy and Alzheimer's disease. In addition, we performed α-synuclein seeding assay from the affected putamen samples. We performed genetic testing for APOE, MAPT, PSEN1, PSEN2 and APP. We refer to the four multiple system atrophy cases with discrepancy between amyloid-β and tau pathology as 'amyloid-β-predominant Alzheimer's disease neuropathologic change-multiple system atrophy' to distinguish these from multiple system atrophy with primary age-related tauopathy or multiple system atrophy with typical Alzheimer's disease neuropathologic change. As most multiple system atrophy cases with mixed pathologies reported in the literature, these cases did not show a peculiar clinical or MRI profile. Three amyloid-β-predominant Alzheimer's disease neuropathologic change-multiple system atrophy cases were available for genetic testing, and all carried the APOE ɛ4 allele. The extent and severity of neuronal loss and α-synuclein pathology were not different compared with typical multiple system atrophy cases. Analysis of amyloid-β peptides revealed more premature amyloid-β plaques in amyloid-β-predominant Alzheimer's disease neuropathologic change-multiple system atrophy compared with Alzheimer's disease. α-Synuclein seeding amplification assay showed differences in the kinetics in two cases. This study highlights a rare mixed pathology variant of multiple system atrophy in which there is an anatomical meeting point of amyloid-β and α-synuclein, i.e. the striatum or cerebellum. Since biomarkers are entering clinical practice, these cases will be recognized, and the clinicians have to be informed that the prognosis is not necessarily different than in pure multiple system atrophy cases but that the effect of potential α-synuclein-based therapies might be influenced by the co-presence of amyloid-β in regions where α-synuclein also aggregates. We propose that mixed pathologies should be interpreted not only based on differences in the clinical phenotype but also on whether protein depositions regionally overlap, potentially leading to a different response to α-synuclein-targeted therapies.

Revisiting the relevance of Hirano bodies in neurodegenerative diseases

AIMS

Hirano bodies (HBs) are eosinophilic pathological structures with two morphological phenotypes commonly found in the hippocampal CA1 region in Alzheimer's disease (AD). This study evaluated the prevalence and distribution of HBs in AD and other neurodegenerative diseases.

METHODS

This cross-sectional study systematically evaluated HBs in a cohort of 193 cases with major neurodegenerative diseases, including AD (n = 91), Lewy body disease (LBD, n = 87), progressive supranuclear palsy (PSP, n = 36), multiple system atrophy (MSA, n = 14) and controls (n = 26). The prevalence, number and morphology of HBs in the stratum lacunosum (HBL) and CA1 pyramidal cell layer were examined. In addition, we investigated the presence of HBs in five additional hippocampal subregions.

RESULTS

The morphological types of HBs in CA1 were divided into three, including a newly discovered type, and were evaluated separately, with their morphology confirmed in three dimensions: (1) classic rod-shaped HB (CHB), (2) balloon-shaped HB (BHB) and the newly described (3) string-shaped HB (SHB). The prevalence of each HB type differed between disease groups: Compared with controls, for CHB in AD, AD + LBD, PSP and corticobasal degeneration, for BHB in AD + LBD and PSP, and SHB in AD + LBD and PSP were significantly increased. Regression analysis showed that CHBs were independently associated with higher Braak NFT stage, BHBs with LBD and TDP-43 pathology, SHBs with higher Braak NFT stage, PSP and argyrophilic grain disease and HBLs with MSA.

CONCLUSIONS

This study demonstrates that HBs are associated with diverse neurodegenerative diseases and shows that morphological types appear distinctively in various conditions.

Molecular Behavior of α-Synuclein Is Associated with Membrane Transport, Lipid Metabolism, and Ubiquitin-Proteasome Pathways in Lewy Body Disease

Lewy body diseases (LBDs) feature α-synuclein (α-syn)-containing Lewy bodies, with misfolded α-syn potentially propagating as seeds. Using a seeding amplification assay, we previously reported distinct α-syn seeding in LBD cases based on the area under seeding curves. This study revealed that LBD cases showing different α-syn seeding kinetics have distinct proteomics profiles, emphasizing disruptions in mitochondria and lipid metabolism in high-seeder cases. Though the mechanisms underlying LBD development are intricate, the factors influencing α-syn seeding activity remain elusive. To address this and complement our previous findings, we conducted targeted transcriptome analyses in the substantia nigra using the nanoString nCounter assay together with histopathological evaluations in high (n = 4) and low (n = 3) nigral α-syn seeders. Neuropathological findings (particularly the substantia nigra) were consistent between these groups and were characterized by neocortical LBD associated with Alzheimer's disease neuropathologic change. Among the 1811 genes assessed, we identified the top 20 upregulated and downregulated genes and pathways in α-syn high seeders compared with low seeders. Notably, alterations were observed in genes and pathways related to transmembrane transporters, lipid metabolism, and the ubiquitin-proteasome system in the high α-syn seeders. In conclusion, our findings suggest that the molecular behavior of α-syn is the driving force in the neurodegenerative process affecting the substantia nigra through these identified pathways. These insights highlight their potential as therapeutic targets for attenuating LBD progression.

The molecular spectrum of amyloid-beta (Aβ) in neurodegenerative diseases beyond Alzheimer's disease

This study investigated the molecular spectrum of amyloid-beta (Aβ) in neurodegenerative diseases beyond Alzheimer's disease (AD). We analyzed Aβ deposition in the temporal cortex and striatum in 116 autopsies, including Lewy body disease (LBD; N = 51), multiple system atrophy (MSA; N = 10), frontotemporal lobar degeneration-TDP-43 (FTLD-TDP; N = 16), and progressive supranuclear palsy (PSP; N = 39). The LBD group exhibited the most Aβ deposition in the temporal cortex and striatum (90/76%, respectively), followed by PSP (69/28%), FTLD-TDP (50/25%), and the MSA group (50/10%). We conducted immunohistochemical analysis using antibodies targeting eight Aβ epitopes in the LBD and PSP groups. Immunohistochemical findings were evaluated semi-quantitatively and quantitatively using digital pathology. Females with LBD exhibited significantly more severe Aβ deposition, particularly Aβ42 and Aβ43 , along with significantly more severe tau pathology. Furthermore, a quantitative analysis of all Aβ peptides in the LBD group revealed an association with the APOE-ε4 genotypes. No significant differences were observed between males and females in the PSP group. Finally, we compared striatal Aβ deposition in cases with LBD (N = 15), AD without α-synuclein pathology (N = 6), and PSP (N = 5). There were no differences in the pan-Aβ antibody (6F/3D)-immunolabeled deposition burden among the three groups, but the deposition burden of peptides with high aggregation capacity, especially Aβ43 , was significantly higher in the AD and LBD groups than in the PSP group. Furthermore, considerable heterogeneity was observed in the composition of Aβ peptides on a case-by-case basis in the AD and LBD groups, whereas it was relatively uniform in the PSP group. Cluster analysis further supported these findings. Our data suggest that the type of concomitant proteinopathies influences the spectrum of Aβ deposition, impacted also by sex and APOE genotypes.

Neuronal SNCA transcription during Lewy body formation

Misfolded α-synuclein (α-syn) is believed to contribute to neurodegeneration in Lewy body disease (LBD) based on considerable evidence including a gene-dosage effect observed in relation to point mutations and multiplication of SNCA in familial Parkinson's disease. A contradictory concept proposes early loss of the physiological α-syn as the major driver of neurodegeneration. There is a paucity of data on SNCA transcripts in various α-syn immunoreactive cytopathologies. Here, the total cell body, nuclear, and cytoplasmic area density of SNCA transcripts in neurons without and with various α-syn immunoreactive cytopathologies in the substantia nigra and amygdala in autopsy cases of LBD (n = 5) were evaluated using RNAscope combined with immunofluorescence for disease-associated α-syn. Single-nucleus RNA sequencing was performed to elucidate cell-type specific SNCA expression in non-diseased frontal cortex (n = 3). SNCA transcripts were observed in the neuronal nucleus and cytoplasm in neurons without α-syn, those containing punctate α-syn immunoreactivity, irregular-shaped compact inclusion, and brainstem-type and cortical-type LBs. However, SNCA transcripts were only rarely found in the α-syn immunoreactive LB areas. The total cell body SNCA transcript area densities in neurons with punctate α-syn immunoreactivity were preserved but were significantly reduced in neurons with compact α-syn inclusions both in the substantia nigra and amygdala. This reduction was also observed in the cytoplasm but not in the nucleus. Only single SNCA transcripts were detected in astrocytes with or without disease-associated α-syn immunoreactivity in the amygdala. Single-nucleus RNA sequencing revealed that excitatory and inhibitory neurons, oligodendrocyte progenitor cells, oligodendrocytes, and homeostatic microglia expressed SNCA transcripts, while expression was largely absent in astrocytes and microglia. The preserved cellular SNCA expression in the more abundant non-Lewy body type α-syn cytopathologies might provide a pool for local protein production that can aggregate and serve as a seed for misfolded α-syn. Successful segregation of disease-associated α-syn is associated with the exhaustion of SNCA production in the terminal cytopathology, the Lewy body. Our observations inform therapy development focusing on targeting SNCA transcription in LBD.

Changes in sleep and the prevalence of probable insomnia in undergraduate university students over the course of the COVID-19 pandemic: findings from the U-Flourish cohort study

BACKGROUND

Sleep problems associated with poor mental health and academic outcomes may have been exacerbated by the COVID-19 pandemic.

AIMS

To describe sleep in undergraduate students during the COVID-19 pandemic.

METHOD

This longitudinal analysis included data from 9523 students over 4 years (2018-2022), associated with different pandemic phases. Students completed a biannual survey assessing risk factors, mental health symptoms and lifestyle, using validated measures. Sleep was assessed with the Sleep Condition Indicator (SCI-8). Propensity weights and multivariable log-binomial regressions were used to compare sleep in four successive first-year cohorts. Linear mixed-effects models were used to examine changes in sleep over academic semesters and years.

RESULTS

There was an overall decrease in average SCI-8 scores, indicating worsening sleep across academic years (average change -0.42 per year; P-trend < 0.001), and an increase in probable insomnia at university entry (range 18.1-29.7%; P-trend < 0.001) before and up to the peak of the pandemic. Sleep improved somewhat in autumn 2021, when restrictions loosened. Students commonly reported daytime sleep problems, including mood, energy, relationships (36-48%) and concentration, productivity, and daytime sleepiness (54-66%). There was a consistent pattern of worsening sleep over the academic year. Probable insomnia was associated with increased cannabis use and passive screen time, and reduced recreation and exercise.

CONCLUSIONS

Sleep difficulties are common and persistent in students, were amplified by the pandemic and worsen over the academic year. Given the importance of sleep for well-being and academic success, a preventive focus on sleep hygiene, healthy lifestyle and low-intensity sleep interventions seems justified.

Misfolded α-Synuclein in Cerebrospinal Fluid of Contact Sport Athletes

BACKGROUND

Misfolded α-synuclein in Parkinson's disease (PD) and dementia with Lewy bodies (DLB) can be detected using the real-time quaking-induced conversion (RT-QuIC) technique in cerebrospinal fluid (CSF).

OBJECTIVES

The objectives are (1) to examine misfolded CSF α-synuclein incidence, and (2) to compare clinical presentation, sports history, brain volumes, and RT-QuIC α-synuclein positivity in former athletes.

METHODS

Thirty former athletes with magnetic resonance imaging, neuropsychological testing, and CSF analyzed for phosphorylated tau 181 (p-tau), total tau (t-tau), amyloid-β 42 (Aβ42), and neurofilament light chain (NfL). CSF α-synuclein was detected using RT-QuIC.

RESULTS

Six (20%) former athletes were α-synuclein positive. α-Synuclein positive athletes were similar to α-synuclein negative athletes on demographics, sports history, clinical features, CSF p-tau, t-tau, Aβ42, and NfL; however, had lower grey matter volumes in the right inferior orbitofrontal, right anterior insula and right olfactory cortices.

CONCLUSIONS

α-Synuclein RT-QuIC analysis of CSF may be useful as a prodromal biofluid marker of PD and DLB. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Distinct Molecular Signatures of Amyloid-Beta and Tau in Alzheimer's Disease Associated with Down Syndrome

Limited comparative data exist on the molecular spectrum of amyloid-beta (Aβ) and tau deposition in individuals with Down syndrome (DS) and sporadic Alzheimer's disease (sAD). We assessed Aβ and tau deposition severity in the temporal lobe and cerebellum of ten DS and ten sAD cases. Immunohistochemistry was performed using antibodies against eight different Aβ epitopes (6F/3D, Aβ38, Aβ39, Aβ40, Aβ42, Aβ43, pyroglutamate Aβ at third glutamic acid (AβNp3E), phosphorylated- (p-)Aβ at 8th serine (AβpSer8)), and six different pathological tau epitopes (p-Ser202/Thr205, p-Thr231, p-Ser396, Alz50, MC1, GT38). Findings were evaluated semi-quantitatively and quantitatively using digital pathology. DS cases had significantly higher neocortical parenchymal deposition (Aβ38, Aβ42, and AβpSer8), and cerebellar parenchymal deposition (Aβ40, Aβ42, AβNp3E, and AβpSer8) than sAD cases. Furthermore, DS cases had a significantly larger mean plaque size (6F/3D, Aβ42, AβNp3E) in the temporal lobe, and significantly greater deposition of cerebral and cerebellar Aβ42 than sAD cases in the quantitative analysis. Western blotting corroborated these findings. Regarding tau pathology, DS cases had significantly more severe cerebral tau deposition than sAD cases, especially in the white matter (p-Ser202/Thr205, p-Thr231, Alz50, and MC1). Greater total tau deposition in the white matter (p-Ser202/Thr205, p-Thr231, and Alz50) of DS cases was confirmed by quantitative analysis. Our data suggest that the Aβ and tau molecular signatures in DS are distinct from those in sAD.

Childhood Adversity and Mental Health Outcomes Among University Students: A Longitudinal Study

BACKGROUND

Mental health concerns are common among university students and maybe elevated among those with specific risk exposures. The study examined the association between childhood adversities and mental health outcomes among undergraduate university students and assessed whether psychosocial and behavioral factors mediate those associations.

METHODS

The Queen's University Student Well-Being and Academic Success Survey identified two large cohorts of first-year undergraduate students entering university in Fall 2018 and 2019 (n = 5,943). At baseline, students reported sociodemographic information, family-related mental health history, childhood physical abuse, sexual abuse, peer bullying, and parental separation or divorce. Baseline and follow-up surveys in Spring 2019, Fall 2019, and Spring 2020 included validated measures of anxiety (7-item Generalized Anxiety Disorder) and depressive symptoms (9-item Patient Health Questionnaire ), non-suicidal self-harm, and suicidality, along with psychological processes and lifestyle variables. Repeated measures logistic regression using Generalized Estimating Equations was used to characterize the associations between childhood adversities and mental health outcomes and examine potential mediation.

RESULTS

Adjusting for age, gender, ethnicity, familial mental illness, and parental education, any childhood abuse (odds ratio: 2.89; 95% confidence interval, 2.58 to 3.23) and parental separation or divorce (odds ratio: 1.29; 95% confidence interval, 1.12 to 1.50) were significantly associated with a composite indicator of mental health outcomes (either 9-item Patient Health Questionnaire score ≥10 or 7-item Generalized Anxiety Disorderscore ≥10 or suicidality or self-harm). The association with childhood abuse weakened when adjusted for perceived stress, self-esteem, and insomnia (odds ratio: 2.05; 95% confidence interval, 1.80 to 2.34), and that with parental divorce weakened when adjusted for self-esteem (odds ratio: 1.17; 95% confidence interval, 1.00 to 1.36).

CONCLUSION

Childhood abuse and parental separation or divorce were associated with mental health concerns among university students. Childhood adversities may impact later mental health through an association with stress sensitivity, self-esteem, and sleep problems. The findings suggest that prevention and early intervention focusing on improving sleep, self-esteem, and coping with stress while considering the individual risk profile of help-seeking students may help support student mental health.

The Impact of the COVID-19 Pandemic on the Mental Health of First-Year Undergraduate Students Studying at a Major Canadian University: A Successive Cohort Study

OBJECTIVE

To examine the impact of the COVID-19 pandemic on first year undergraduate student mental health.

METHODS

As part of the Queen's University U-Flourish Student Well-Being and Academic Success study, three successive cohorts of students entering undergraduate studies in 2018 (pre-pandemic), 2019 (transitional), and 2020 (during pandemic) completed electronic surveys at entry and completion of first year. Validated self-report measures were used to assess mental health status including symptom levels of anxiety, depression, and insomnia, self-harm and frequency of substance use. Propensity matching and multivariable log-binomial regression were used in comparisons of mental health indicators across the cohorts.

RESULTS

Clinically significant symptoms of depression, anxiety, insomnia, and self-harm were reported more frequently in the 2020-2021 cohort, coincident with remote learning and pandemic restrictions. In female students, screen positive rates for anxiety and depression, and suicidal ideation increased from about one-third to just under one-half in association with the pandemic (χ2, p < .01), while increases in mental health concerns were less pronounced among males. Among females, increases in clinically significant symptoms over first year appeared greatest during the pandemic year, while striking decreases in alcohol consumption in both females and males were reported in that same year. Studying under pandemic conditions had a negative impact on student well-being, social relationships and school connectedness, quality of learning experience, leisure activities, and optimism about future prospects.

CONCLUSIONS

Mental health concerns including anxiety, depression and sleep problems increased in first year students during the pandemic, especially among females, while alcohol use declined. These findings highlight the negative mental health impact associated with studying under pandemic restrictions involving remote learning and social distancing.

Does the morphology of cutaneous melanoma help to explain the international differences in survival? Results from 1 578 482 adults diagnosed during 2000-2014 in 59 countries (CONCORD-3)

BACKGROUND

CONCORD-3 highlighted wide disparities in population-based 5-year net survival for cutaneous melanoma during 2000-2014. Clinical evidence suggests marked international differences in the proportion of lethal acral and nodular subtypes of cutaneous melanoma.

OBJECTIVES

We aimed to assess whether the differences in morphology may explain global variation in survival.

METHODS

Patients with melanoma were grouped into the following seven morphological categories: malignant melanoma, not otherwise specified (International Classification of Diseases for Oncology, third revision morphology code 8720), superficial spreading melanoma (8743), lentigo maligna melanoma (8742), nodular melanoma (8721), acral lentiginous melanoma (8744), desmoplastic melanoma (8745) and other morphologies (8722-8723, 8726-8727, 8730, 8740-8741, 8746, 8761, 8770-8774, 8780). We estimated net survival using the nonparametric Pohar Perme estimator, correcting for background mortality by single year of age, sex and calendar year in each country or region. All-ages survival estimates were standardized using the International Cancer Survival Standard weights. We fitted a flexible parametric model to estimate the effect of morphology on the hazard of death.

RESULTS

Worldwide, the proportion of nodular melanoma ranged between 7% and 13%. Acral lentiginous melanoma accounted for less than 2% of all registrations but was more common in Asia (6%) and Central and South America (7%). Overall, 36% of tumours were classified as superficial spreading melanoma. During 2010-2014, age-standardized 5-year net survival for superficial spreading melanoma was 95% or higher in Oceania, North America and most European countries, but was only 71% in Taiwan. Survival for acral lentiginous melanoma ranged between 66% and 95%. Nodular melanoma had the poorest prognosis in all countries. The multivariable analysis of data from registries with complete information on stage and morphology found that sex, age and stage at diagnosis only partially explain the higher risk of death for nodular and acral lentiginous subtypes.

CONCLUSIONS

This study provides the broadest picture of distribution and population-based survival trends for the main morphological subtypes of cutaneous melanoma in 59 countries. The poorer prognosis for nodular and acral lentiginous melanomas, more frequent in Asia and Latin America, suggests the need for health policies aimed at specific populations to improve awareness, early diagnosis and access to treatment. What is already known about this topic? The histopathological features of cutaneous melanoma vary markedly worldwide. The proportion of melanomas with the more aggressive acral lentiginous or nodular histological subtypes is higher in populations with predominantly dark skin than in populations with predominantly fair skin. What does this study add? We aimed to assess the extent to which these differences in morphology may explain international variation in survival when all histological subtypes are combined. This study provides, for the first time, international comparisons of population-based survival at 5 years for the main histological subtypes of melanoma for over 1.5 million adults diagnosed during 2000-2014. This study highlights the less favourable distribution of histological subtypes in Asia and Central and South America, and the poorer prognosis for nodular and acral lentiginous melanomas. We found that later stage at diagnosis does not fully explain the higher excess risk of death for nodular and acral lentiginous melanoma compared with superficial spreading melanoma.