Brain arteriolosclerosis.

Brain arteriolosclerosis (B-ASC), characterized by pathologic arteriolar wall thickening, is a common finding at autopsy in aged persons and is associated with cognitive impairment. Hypertension and diabetes are widely recognized as risk factors for B-ASC. Recent research indicates other and more complex risk factors and pathogenetic mechanisms. Here, we describe aspects of the unique architecture of brain arterioles, histomorphologic features of B-ASC, relevant neuroimaging findings, epidemiology and association with aging, established genetic risk factors, and the co-occurrence of B-ASC with other neuropathologic conditions such as Alzheimer's disease and limbic-predominant age-related TDP-43 encephalopathy (LATE). There may also be complex physiologic interactions between metabolic syndrome (e.g., hypertension and inflammation) and brain arteriolar pathology. Although there is no universally applied diagnostic methodology, several classification schemes and neuroimaging techniques are used to diagnose and categorize cerebral small vessel disease pathologies that include B-ASC, microinfarcts, microbleeds, lacunar infarcts, and cerebral amyloid angiopathy (CAA). In clinical-pathologic studies that factored in comorbid diseases, B-ASC was independently associated with impairments of global cognition, episodic memory, working memory, and perceptual speed, and has been linked to autonomic dysfunction and motor symptoms including parkinsonism. We conclude by discussing critical knowledge gaps related to B-ASC and suggest that there are probably subcategories of B-ASC that differ in pathogenesis. Observed in over 80% of autopsied individuals beyond 80 years of age, B-ASC is a complex and under-studied contributor to neurologic disability.

Associations Between Plasma Ceramides and Cerebral Microbleeds or Lacunes.

OBJECTIVE: High plasma ceramide levels and ratios are associated with poor outcomes in individuals with cardiovascular disease; less is known about their relation to cerebral small vessel disease. We examined whether high plasma ceramide levels or ratios were associated with cerebral microbleeds (CMBs) and lacunes and whether associations differ by sex. Approach and Results: We included 548 participants enrolled in the MCSA (Mayo Clinic Study of Aging) with concurrent plasma ceramide assays and magnetic resonance imaging. CMBs were quantified on T2* magnetic resonance imaging and lacunes on T2 fluid-attenuated inversion recovery magnetic resonance imaging. Fasting plasma ceramides were assayed using liquid chromatography-electrospray ionization tandem mass spectrometry. We used logistic regression models adjusting for age, sex, hypertension, and diabetes mellitus to examine the relationship between ceramides and presence of a lacune; hurdle models were used for presence and number of CMBs. Each SD increase in the log ceramide C16:0/24:0 ratio was associated with greater odds of a CMB (odds ratio, 1.28 [95% CI, 1.01-1.64]). There was an interaction between sex and the ceramide C16:0/24:0 ratio (P=0.049). The association between this ratio and presence of a CMB was stronger for women (odds ratio, 1.87 [95% CI, 1.20-3.00]) than men (odds ratio, 1.09 [95% CI, 0.80-1.46]). Several ceramides and all ceramide ratios were associated with number of CMBs. We did not find associations between plasma ceramides and lacunes. CONCLUSIONS: In a population-based sample, the plasma ceramide C16:0/24:0 ratio was associated with CMBs and was stronger for women. Plasma ceramides are differentially associated with cerebral small vessel pathologies.

Outcomes after diagnosis of mild cognitive impairment in a large autopsy series.

OBJECTIVE: To determine clinical and neuropathological outcomes following a clinical diagnosis of mild cognitive impairment (MCI). METHODS: Data were drawn from a large autopsy series (N = 1,337) of individuals followed longitudinally from normal or MCI status to death, derived from 4 Alzheimer Disease (AD) Centers in the United States. RESULTS: Mean follow-up was 7.9 years. Of the 874 individuals ever diagnosed with MCI, final clinical diagnoses were varied: 39.2% died with an MCI diagnosis, 46.8% with a dementia diagnosis, and 13.9% with a diagnosis of intact cognition. The latter group had pathological features resembling those with a final clinical diagnosis of MCI. In terms of non-AD pathologies, both primary age-related tauopathy (p < 0.05) and brain arteriolosclerosis pathology (p < 0.001) were more severe in MCI than cognitively intact controls. Among the group that remained MCI until death, mixed AD neuropathologic changes (ADNC; ≥1 comorbid pathology) were more frequent than "pure" ADNC pathology (55% vs 22%); suspected non-Alzheimer pathology comprised the remaining 22% of cases. A majority (74%) of subjects who died with MCI were without "high"-level ADNC, Lewy body disease, or hippocampal sclerosis pathologies; this group was enriched in cerebrovascular pathologies. Subjects who died with dementia and were without severe neurodegenerative pathologies tended to have cerebrovascular pathology and carry the MCI diagnosis for a longer interval. INTERPRETATION: MCI diagnosis usually was associated with comorbid neuropathologies; less than one-quarter of MCI cases showed "pure" AD at autopsy. Ann Neurol 2017;81:549-559.

Creating an Undergraduate Research Program in Otolaryngology-Head and Neck Surgery (Oto-HNS) for Students Underrepresented in Medicine.

Objectives: To report implementation and outcomes associated with a novel paid Summer Undergraduate Research Education Program (SREP) over the first 2 years in an academic otolaryngology program recruiting students underrepresented in medicine (URiM). Methods: A 10-week program including a research bootcamp, curriculum, mentoring, and clinical shadowing was created. Grant funding to provide salary and support for transportation, conference attendance, and graduate school preparation or applications was procured. Primary objectives included (1) development of successful mentorship relationships; (2) increasing student-reported outcomes using pre- and post-program surveys to assess confidence, career planning, and overall satisfaction; (3) increasing exposure to medicine; (4) completion of an oral presentation; and (5) submission of a manuscript. Secondary objectives included abstract submission and completion of a graduate exam course or graduate school applications. Tertiary objectives included conference attendance and graduate school matriculation. Results: One hundred thirty-five total applications were reviewed (89 from year 1 and 46 from year 2). Twelve students were interviewed for 3 spots in year 1, while 11 students were interviewed for 6 spots in year 2 (median application score, 9.25 (range, 1-14); median interview score, 8.7 (range, 5.4-10); acceptance rate, 6.7% (9/135)). Students met all primary objectives. Mean program survey scores increased from 3.8 to 4.77 (p < 0.0001). Eight of nine students submitted an abstract to a national conference, with five of eight students accepted for a presentation. Two students were accepted into graduate school, while five others are on track for graduate school application. Conclusion: Identifying mentors, curriculum, and opportunities to meaningfully strengthen graduate school applications for URiM students through a clinically rigorous, financially supported, and research-focused summer program in an academic otolaryngology program is feasible and may be an effective means of increasing diversity in medicine and otolaryngology. Supplementary Information: The online version contains supplementary material available at 10.1007/s40670-024-02021-z.

Racial and Ethnic Bias in the Diagnosis of Alcohol Use Disorder in Veterans.

OBJECTIVE: Studies show that racially and ethnically minoritized veterans have a higher prevalence of alcohol use disorder (AUD) than White veterans. The investigators examined whether the relationship between self-reported race and ethnicity and AUD diagnosis remains after adjusting for alcohol consumption, and if so, whether it varies by self-reported alcohol consumption. METHODS: The sample included 700,012 Black, White, and Hispanic veterans enrolled in the Million Veteran Program. Alcohol consumption was defined as an individual's maximum score on the consumption subscale of the Alcohol Use Disorders Identification Test (AUDIT-C), a screen for unhealthy alcohol use. A diagnosis of AUD, the primary outcome, was defined by the presence of relevant ICD-9 or ICD-10 codes in electronic health records. Logistic regression with interactions was used to assess the association between race and ethnicity and AUD as a function of maximum AUDIT-C score. RESULTS: Black and Hispanic veterans were more likely than White veterans to have an AUD diagnosis despite similar levels of alcohol consumption. The difference was greatest between Black and White men; at all but the lowest and highest levels of alcohol consumption, Black men had 23%-109% greater odds of an AUD diagnosis. The findings were unchanged after adjustment for alcohol consumption, alcohol-related disorders, and other potential confounders. CONCLUSIONS: The large discrepancy in the prevalence of AUD across groups despite a similar distribution of alcohol consumption levels suggests that there is racial and ethnic bias, with Black and Hispanic veterans more likely than White veterans to receive an AUD diagnosis. Efforts are needed to reduce bias in the diagnostic process to address racialized differences in AUD diagnosis.

A neuropathologic feature of brain aging: multi-lumen vascular profiles.

Cerebrovascular pathologies other than frank infarctions are commonly seen in aged brains. Here, we focus on multi-lumen vascular profiles (MVPs), which are characterized by multiple vessel lumens enclosed in a single vascular channel. Little information exists on the prevalence, risk factors, and co-pathologies of MVPs. Therefore, we used samples and data from the University of Kentucky Alzheimer's Disease Research Center (n = 91), the University of Kentucky Pathology Department (n = 31), and the University of Pittsburgh Pathology Department (n = 4) to study MVPs. Age at death was correlated with MVP density in the frontal neocortex, Brodmann Area 9 (r = 0.51; p < 0.0001). Exploratory analyses were performed to evaluate the association between conventional vascular risk factors (e.g., hypertension, diabetes), cardiovascular diseases (e.g., heart attack, arrhythmia), and cerebrovascular disease (e.g., stroke); the only nominal association with MVP density was a self-reported history of brain trauma (Prevalence Ratio = 2.1; 95 CI 1.1-3.9, before correcting for multiple comparisons). No specific associations were detected between neuropathological (e.g., brain arteriolosclerosis) or genetic (e.g., APOE) variables and MVP density. Using a tissue clearing method called SeeDB, we provide 3-dimensional images of MVPs in brain tissue. We conclude that MVPs are an age-related brain pathology and more work is required to identify their clinical-pathological correlation and associated risk factors.

Pearls & Oy-sters: Postpipeline Headache Phenomenon: Nummular Headache Presenting After Intracranial Aneurysm Stenting.

We report on a 31-year-old right-handed woman with a medical history of presyncopal episodes and migraine headaches who presented to the outpatient clinic with a nummular headache after intracerebral stenting, which was different than her previous migraines. This represents postpipeline embolization headache phenomenon, which is a relatively new term to describe a new or different headache in individuals who recently underwent intracranial vascular stenting as a treatment for cerebral aneurysms.

Management of Chronic Subdural Hematoma in Patients Requiring Therapeutic Anticoagulation.

INTRODUCTION: A common risk factor of chronic, nontraumatic subdural hematoma (SDH) is anticoagulation therapy. Anticoagulation is generally held in patients who develop SDH, but this can lead to thromboembolic events. While prior studies have reported the clinical outcomes of patients with anticoagulation-related SDH, there remains little evidence regarding ongoing anticoagulation treatment. CASE REPORT: We report the management of 2 patients who developed anticoagulation-related SDH and underwent middle meningeal artery (MMA) embolization and successful reinitiation of anticoagulation therapy. In both patients, we conservatively managed anticoagulation with heparin and/or enoxaparin as a bridge to warfarin after MMA embolization. Follow-up computed tomography head revealed interval decrease of SDH and stable neurological status. CONCLUSIONS: These cases provide anecdotal evidence of a challenging clinical scenario where there is a necessary indication for therapeutic anticoagulation (ie, venous sinus thrombosis or atrial appendage thrombus) and comorbid SDH. Endovascular MMA embolization may be an effective adjunct therapy for clinical scenarios in patients with SDH and an urgent indication for anticoagulation. Longer follow-up, prospective series, and future randomized clinical trials are needed to objectively assess outcomes in this clinically challenging patient population.

Underreporting and Underrepresentation of Race and Ethnicity in Head and Neck Cancer Trials, 2010-2020: A Systematic Review.

Importance: There is substantial evidence demonstrating racial disparities in the survival outcomes of patients with head and neck cancer. The reporting and representation of race and ethnicity in cancer trials is crucial for generalizability of trial results to patient care and reduction of racial health disparities in head and neck cancers. Racial disparities in oncologic outcomes across various therapeutic interventions may only manifest when diverse races are appropriately represented in trials. Objective: To characterize the reporting and representation of race and ethnicity in head and neck cancer clinical trials. Evidence Review: A systematic search of published trials and those available on ClinicalTrials.gov was conducted to identify 3973 studies from 2010 to 2020. Title, abstract, and full-text review yielded 155 trials for data extraction of patient demographics. Year of publication, type of intervention, publication source, and funding source were also collected. Race and ethnicity data were compared with Surveillance, Epidemiology, and End Results (SEER) Program cancer registry data. Findings: Of the 155 included studies, only 89 (57%) reported race or ethnicity. Only 81 (52%) of the studies reported detailed classification of race or ethnicity per the US Census Bureau classification scheme. Race and ethnicity reporting varied considerably with year of publication, type of intervention, data source, and funding source. Studies in the latter half of the decade were more likely to report race or ethnicity (odds ratio, 2.78; 95% CI, 1.33-5.80), with the highest number in 2019 (24 of 30 [80%] trials), followed by 2020 (20 of 29 [69%] trials). Among the possible interventions, trials on therapeutic chemoradiation most frequently reported race or ethnicity (11 of 12 [92%]), followed by supportive drug trials (22 of 31 [71%]), and then therapeutic chemotherapy trials (28 of 48 [58%]). When compared with SEER data, race and ethnicity distribution in clinical trials showed fewer Black patients (10% vs 8%) and Asian or Pacific Islander patients (6% vs 2%). Conclusions and Relevance: In this systematic review, nearly half of head and neck cancer trials in the past decade did not report the race or ethnicity of participants. Participation of Black and Asian or Pacific Islander patients does not adequately reflect the US population's head and neck cancer demographics, limiting the generalizability of trial results and adding to racial health disparities in patients with head and neck cancers.

Dystrophic microglia are associated with neurodegenerative disease and not healthy aging in the human brain.

Loss of physiological microglial function may increase the propagation of neurodegenerative diseases. Cellular senescence is a hallmark of aging; thus, we hypothesized age could be a cause of dystrophic microglia. Stereological counts were performed for total microglia, 2 microglia morphologies (hypertrophic and dystrophic) across the human lifespan. An age-associated increase in the number of dystrophic microglia was found in the hippocampus and frontal cortex. However, the increase in dystrophic microglia was proportional to the age-related increase in the total number of microglia. Thus, aging alone does not explain the presence of dystrophic microglia. We next tested if dystrophic microglia could be a disease-associated microglia morphology. Compared with controls, the number of dystrophic microglia was greater in cases with either Alzheimer's disease, dementia with Lewy bodies, or limbic-predominant age-related TDP-43 encephalopathy. These results demonstrate that microglia dystrophy, and not hypertrophic microglia, are the disease-associated microglia morphology. Finally, we found strong evidence for iron homeostasis changes in dystrophic microglia, providing a possible molecular mechanism driving the degeneration of microglia in neurodegenerative disease.

Rod-shaped microglia morphology is associated with aging in 2 human autopsy series.

A subtype of microglia is defined by the morphological appearance of the cells as rod shaped. Little is known about this intriguing cell type, as there are only a few case reports describing rod-shaped microglia in the neuropathological literature. Rod-shaped microglia were shown recently to account for a substantial proportion of the microglia cells in the hippocampus of both demented and cognitively intact aged individuals. We hypothesized that aging could be a defining feature in the occurrence of rod-shaped microglia. To test this hypothesis, 2 independent series of autopsy cases (total n = 168 cases), which covered the adult lifespan from 20 to 100+ years old, were included in the study. The presence or absence of rod-shaped microglia was scored on IBA1 immunohistochemically stained slides for the hippocampus and cortex. We found that age was one of the strongest determinants for the presence of rod-shaped microglia in the hippocampus and the cortex. We found no association with the presence of rod-shaped microglia and a self-reported history of a TBI. Alzheimer's disease-related pathology was found to influence the presence of rod-shaped microglia, but only in the parietal cortex and not in the hippocampus or temporal cortex. Future studies are warranted to determine the functional relevance of rod-shaped microglia in supporting the health of neurons in the aged brain, and the signaling processes that regulate the formation of rod-shaped microglia.

Challenges and Considerations Related to Studying Dementia in Blacks/African Americans.

Blacks/African Americans have been reported to be ∼2-4 times more likely to develop clinical Alzheimer's disease (AD) compared to Whites. Unfortunately, study design challenges (e.g., recruitment bias), racism, mistrust of healthcare providers and biomedical researchers, confounders related to socioeconomic status, and other sources of bias are often ignored when interpreting differences in human subjects categorized by race. Failure to account for these factors can lead to misinterpretation of results, reification of race as biology, discrimination, and missed or delayed diagnoses. Here we provide a selected historical background, discuss challenges, present opportunities, and suggest considerations for studying health outcomes among racial/ethnic groups. We encourage neuroscientists to consider shifting away from using biologic determination to interpret data, and work instead toward a paradigm of incorporating both biological and socio-environmental factors known to affect health outcomes with the goal of understanding and improving dementia treatments for Blacks/African Americans and other underserved populations.

Risk factors and global cognitive status related to brain arteriolosclerosis in elderly individuals.

Risk factors and cognitive sequelae of brain arteriolosclerosis pathology are not fully understood. To address this, we used multimodal data from the National Alzheimer's Coordinating Center and Alzheimer's Disease Neuroimaging Initiative data sets. Previous studies showed evidence of distinct neurodegenerative disease outcomes and clinical-pathological correlations in the "oldest-old" compared to younger cohorts. Therefore, using the National Alzheimer's Coordinating Center data set, we analyzed clinical and neuropathological data from two groups according to ages at death: < 80 years (n = 1008) and ≥80 years (n = 1382). In both age groups, severe brain arteriolosclerosis was associated with worse performances on global cognition tests. Hypertension (but not diabetes) was a brain arteriolosclerosis risk factor in the younger group. In the ≥ 80 years age at death group, an ABCC9 gene variant (rs704180), previously associated with aging-related hippocampal sclerosis, was also associated with brain arteriolosclerosis. A post-hoc arterial spin labeling neuroimaging experiment indicated that ABCC9 genotype is associated with cerebral blood flow impairment; in a convenience sample from Alzheimer's Disease Neuroimaging Initiative (n = 15, homozygous individuals), non-risk genotype carriers showed higher global cerebral blood flow compared to risk genotype carriers. We conclude that brain arteriolosclerosis is associated with altered cognitive status and a novel vascular genetic risk factor.

"New Old Pathologies": AD, PART, and Cerebral Age-Related TDP-43 With Sclerosis (CARTS).

The pathology-based classification of Alzheimer's disease (AD) and other neurodegenerative diseases is a work in progress that is important for both clinicians and basic scientists. Analyses of large autopsy series, biomarker studies, and genomics analyses have provided important insights about AD and shed light on previously unrecognized conditions, enabling a deeper understanding of neurodegenerative diseases in general. After demonstrating the importance of correct disease classification for AD and primary age-related tauopathy, we emphasize the public health impact of an underappreciated AD "mimic," which has been termed "hippocampal sclerosis of aging" or "hippocampal sclerosis dementia." This pathology affects >20% of individuals older than 85 years and is strongly associated with cognitive impairment. In this review, we provide an overview of current hypotheses about how genetic risk factors (GRN, TMEM106B, ABCC9, and KCNMB2), and other pathogenetic influences contribute to TDP-43 pathology and hippocampal sclerosis. Because hippocampal sclerosis of aging affects the "oldest-old" with arteriolosclerosis and TDP-43 pathologies that extend well beyond the hippocampus, more appropriate terminology for this disease is required. We recommend "cerebral age-related TDP-43 and sclerosis" (CARTS). A detailed case report is presented, which includes neuroimaging and longitudinal neurocognitive data. Finally, we suggest a neuropathology-based diagnostic rubric for CARTS.

Disease-related microglia heterogeneity in the hippocampus of Alzheimer's disease, dementia with Lewy bodies, and hippocampal sclerosis of aging.

INTRODUCTION: Neuropathological, genetic, and biochemical studies have provided support for the hypothesis that microglia participate in Alzheimer's disease (AD) pathogenesis. Despite the extensive characterization of AD microglia, there are still many unanswered questions, and little is known about microglial morphology in other common forms of age-related dementia: particularly, dementia with Lewy bodies (DLB) and hippocampal sclerosis of aging (HS-Aging). In addition, no prior studies have attempted to compare and contrast the microglia morphology in the hippocampus of various neurodegenerative conditions. RESULTS: Here we studied cases with pathologically-confirmed AD (n = 7), HS-Aging (n = 7), AD + HS-aging (n = 4), DLB (n = 12), and normal (cognitively intact) controls (NC) (n = 9) from the University of Kentucky Alzheimer's Disease Center autopsy cohort. We defined five microglia morphological phenotypes in the autopsy samples: ramified, hypertrophic, dystrophic, rod-shaped, and amoeboid. The Aperio ScanScope digital neuropathological tool was used along with two well-known microglial markers: IBA1 (a marker for both resting and activated microglia) and CD68 (a lysosomal marker in macrophages/microglia associated with phagocytic cells). Hippocampal staining analyses included studies of subregions within the hippocampal formation and nearby white matter. Using these tools and methods, we describe variation in microglial characteristics that show some degree of disease specificity, including, (1) increased microglia density and number in HS-aging and AD + HS-aging; (2) low microglia density in DLB; (3) increased number of dystrophic microglia in HS-aging; and (4) increased proportion of dystrophic to all microglia in DLB. CONCLUSIONS: We conclude that variations in morphologies among microglial cells, and cells of macrophage lineage, can help guide future work connecting neuroinflammatory mechanisms with specific neurodegenerative disease subtypes.

Hippocampal Sclerosis of Aging Can Be Segmental: Two Cases and Review of the Literature.

Hippocampal sclerosis of aging (HS-Aging) is a neurodegenerative disease that mimics Alzheimer disease (AD) clinically and has a prevalence rivaling AD in advanced age. Whereas clinical biomarkers are not yet optimized, HS-Aging has distinctive pathological features that distinguish it from other diseases with "hippocampal sclerosis" pathology, such as epilepsy, cerebrovascular perturbations, and frontotemporal lobar degeneration. By definition, HS-Aging brains show neuronal cell loss and gliosis in the hippocampal formation out of proportion to AD-type pathology; it is strongly associated with aberrant TDP-43 pathology and arteriolosclerosis. Here, we describe 2 cases of "segmental" HS-Aging in which "sclerosis" in the hippocampus was evident only in a subset of brain sections by hematoxylin and eosin (H&E) stain. In these cases, TDP-43 pathology was more widespread on immunostained sections than the neuronal cell loss and gliosis seen in H&E stains. The 2 patients were cognitively intact at baseline and were tracked longitudinally over a decade using cognitive studies with at least 1 neuroimaging scan. We discuss the relevant HS-Aging literature, which indicates the need for a clearer consensus-based delineation of "hippocampal sclerosis" and TDP-43 pathologies in aged subjects.