Faculty Bibliography

INTRODUCTION/BACKGROUND:Neurological complications among hospitalized COVID-19 patients may be associated with elevated neurodegenerative biomarkers. METHODS:Among hospitalized COVID-19 patients without a history of dementia (N = 251), we compared serum total tau (t-tau), phosphorylated tau-181 (p-tau181), glial fibrillary acidic protein (GFAP), neurofilament light chain (NfL), ubiquitin carboxy-terminal hydrolase L1 (UCHL1), and amyloid beta (Aβ40,42) between patients with or without encephalopathy, in-hospital death versus survival, and discharge home versus other dispositions. COVID-19 patient biomarker levels were also compared to non-COVID cognitively normal, mild cognitive impairment (MCI), and Alzheimer's disease (AD) dementia controls (N = 161). RESULTS:Admission t-tau, p-tau181, GFAP, and NfL were significantly elevated in patients with encephalopathy and in those who died in-hospital, while t-tau, GFAP, and NfL were significantly lower in those discharged home. These markers correlated with severity of COVID illness. NfL, GFAP, and UCHL1 were higher in COVID patients than in non-COVID controls with MCI or AD. DISCUSSION/CONCLUSIONS:Neurodegenerative biomarkers were elevated to levels observed in AD dementia and associated with encephalopathy and worse outcomes among hospitalized COVID-19 patients.

The increased life expectancy of individuals with Down syndrome (DS) is associated with increased prevalence of trisomy 21-linked early-onset Alzheimer's disease (EOAD) and dementia. The aims of this study of 14 brain regions including the entorhinal cortex, hippocampus, basal ganglia, and cerebellum in 33 adults with DS 26-72 years of age were to identify the magnitude of brain region-specific developmental neuronal deficits contributing to intellectual deficits, to apply this baseline to identification of the topography and magnitude of neurodegeneration and neuronal and volume losses caused by EOAD, and to establish age-based staging of the pattern of genetically driven neuropathology in DS. Both DS subject age and stage of dementia, themselves very strongly correlated, were strong predictors of an AD-associated decrease of the number of neurons, considered a major contributor to dementia. The DS cohort was subclassified by age as pre-AD stage, with 26-41-year-old subjects with a full spectrum of developmental deficit but with very limited incipient AD pathology, and 43-49, 51-59, and 61-72-year-old groups with predominant prevalence of mild, moderately severe, and severe dementia respectively. This multiregional study revealed a 28.1% developmental neuronal deficit in DS subjects 26-41 years of age and 11.9% AD-associated neuronal loss in DS subjects 43-49 years of age; a 28.0% maximum neuronal loss at 51-59 years of age; and a 11.0% minimum neuronal loss at 61-72 years of age. A total developmental neuronal deficit of 40.8 million neurons and AD-associated neuronal loss of 41.6 million neurons reflect a comparable magnitude of developmental neuronal deficit contributing to intellectual deficits, and AD-associated neuronal loss contributing to dementia. This highly predictable pattern of pathology indicates that successful treatment of DS subjects in the fourth decade of life may prevent AD pathology and functional decline.

AIMS/OBJECTIVE:Hippocampal findings are implicated in the pathogenesis of sudden unexplained death in childhood (SUDC), although some studies have identified similar findings in sudden explained death in childhood (SEDC) cases. We blindly reviewed hippocampal histology in SUDC and SEDC controls. METHODS:Hippocampal H&E slides (n=67; 36 SUDC, 31 controls) from clinical and forensic collaborators were evaluated by 9 blinded reviewers: 3 board-certified forensic pathologists, 3 neuropathologists, and 3 dual-certified neuropathologist/forensic pathologists. RESULTS:Among nine reviewers, about 50% of hippocampal sections were rated as abnormal (SUDC 52.5%, controls 53.0%), with no difference by cause of death (COD) (p=0.16) or febrile seizure history (p=0.90). There was little agreement among nine reviewers on whether a slide was within normal range (Fleiss' kappa=0.014, p=0.47). Within reviewer groups, there were no findings more frequent in SUDC compared to controls, with variability in pyramidal neuron and dentate gyrus findings. Across reviewer groups, there was concordance for bilamination and granule cell loss. Neither SUDC (51.2%) nor control (55.9%) slides were considered contributory to determining COD (p=0.41). CONCLUSIONS:The lack of an association of hippocampal findings in SUDC and controls, as well as inconsistency of observations by multiple blinded reviewers, indicates discrepancy with previous studies and an inability to reliably identify hippocampal malformation associated with sudden death (HMASD). These findings underscore a need for larger studies to standardize evaluation of hippocampal findings, identify the range of normal variation and, changes unrelated to SUDC or febrile seizures. Molecular studies may help identify novel immunohistological markers that inform on COD.

BACKGROUND:Visual tests in Alzheimer disease (AD) have been examined over the last several decades to identify a sensitive and noninvasive marker of the disease. Rapid automatized naming (RAN) tasks have shown promise for detecting prodromal AD or mild cognitive impairment (MCI). The purpose of this investigation was to determine the capacity for new rapid image and number naming tests and other measures of visual pathway structure and function to distinguish individuals with MCI due to AD from those with normal aging and cognition. The relation of these tests to vision-specific quality of life scores was also examined in this pilot study. METHODS:Participants with MCI due to AD and controls from well-characterized NYU research and clinical cohorts performed high and low-contrast letter acuity (LCLA) testing, as well as RAN using the Mobile Universal Lexicon Evaluation System (MULES) and Staggered Uneven Number test, and vision-specific quality of life scales, including the 25-Item National Eye Institute Visual Function Questionnaire (NEI-VFQ-25) and 10-Item Neuro-Ophthalmic Supplement. Individuals also underwent optical coherence tomography scans to assess peripapillary retinal nerve fiber layer and ganglion cell/inner plexiform layer thicknesses. Hippocampal atrophy on brain MRI was also determined from the participants' Alzheimer disease research center or clinical data. RESULTS:Participants with MCI (n = 14) had worse binocular LCLA at 1.25% contrast compared with controls (P = 0.009) and longer (worse) MULES test times (P = 0.006) with more errors in naming images (P = 0.009) compared with controls (n = 16). These were the only significantly different visual tests between groups. MULES test times (area under the receiver operating characteristic curve [AUC] = 0.79), MULES errors (AUC = 0.78), and binocular 1.25% LCLA (AUC = 0.78) showed good diagnostic accuracy for distinguishing MCI from controls. A combination of the MULES score and 1.25% LCLA demonstrated the greatest capacity to distinguish (AUC = 0.87). These visual measures were better predictors of MCI vs control status than the presence of hippocampal atrophy on brain MRI in this cohort. A greater number of MULES test errors (rs = -0.50, P = 0.005) and worse 1.25% LCLA scores (rs = 0.39, P = 0.03) were associated with lower (worse) NEI-VFQ-25 scores. CONCLUSIONS:Rapid image naming (MULES) and LCLA are able to distinguish MCI due to AD from normal aging and reflect vision-specific quality of life. Larger studies will determine how these easily administered tests may identify patients at risk for AD and serve as measures in disease-modifying therapy clinical trials.

Epilepsy is a common neurological disorder affecting over 70 million people worldwide, with a high rate of pharmaco-resistance, diverse comorbidities including progressive cognitive and behavioural disorders, and increased mortality from direct (e.g. sudden unexpected death in epilepsy, accidents, drowning) or indirect effects of seizures and therapies. Extensive research with animal models and human studies provides limited insights into the mechanisms underlying seizures and epileptogenesis, and these have not translated into significant reductions in pharmaco-resistance, morbidities or mortality. To help define changes in molecular signalling networks associated with seizures in epilepsy with a broad range of aetiologies, we examined the proteome of brain samples from epilepsy and control cases. Label-free quantitative mass spectrometry was performed on the hippocampal cornu ammonis 1-3 region (CA1-3), frontal cortex and dentate gyrus microdissected from epilepsy and control cases (n = 14/group). Epilepsy cases had significant differences in the expression of 777 proteins in the hippocampal CA1 - 3 region, 296 proteins in the frontal cortex and 49 proteins in the dentate gyrus in comparison to control cases. Network analysis showed that proteins involved in protein synthesis, mitochondrial function, G-protein signalling and synaptic plasticity were particularly altered in epilepsy. While protein differences were most pronounced in the hippocampus, similar changes were observed in other brain regions indicating broad proteomic abnormalities in epilepsy. Among the most significantly altered proteins, G-protein subunit beta 1 (GNB1) was one of the most significantly decreased proteins in epilepsy in all regions studied, highlighting the importance of G-protein subunit signalling and G-protein-coupled receptors in epilepsy. Our results provide insights into common molecular mechanisms underlying epilepsy across various aetiologies, which may allow for novel targeted therapeutic strategies.

Background: Modern, highly efficient hemodialysis (HD) results in rapid decline of blood urea. Urea gradients across the blood-brain barrier (BBB) can drive water movements. A positive urea gradient, i.e. brain urea to plasma urea, can result in brain swelling and impair brain function. We explored the dialytic changes of urea in blood and cerebrospinal fluid (CSF) to better understand intradialytic osmotic gradients across the BBB and provide insights that support the development of brain-protective HD.
Method(s): Two HD patients (39 and 26 years old) with ventriculo-peritoneal (VP) shunts were enrolled into this one-week IRB-approved study with a Monday/Wednesday/ Friday dialysis schedule. CSF was collected via VP shunt tap 2 hrs before and 2 hrs after HD (Wednesday and Friday), and Tuesday and Thursday. Plasma samples were collected concurrently with CSF and during HD. In addition, the patients underwent test of executive function (Trail Making Test Part B; TMT B) and global cognitive function (Montreal Cognitive Assessment; MoCA) on Monday.
Result(s): Urea was removed efficiently from patients' blood by HD. While patient A showed a small post-HD plasma-to-CSF urea gradient, it was highly positive (~ 60 mg/dL) in patient B (Fig. 1). TMT B and MoCA score were normal for patient A but not patient B (TMT B 415 sec; TMT B error count: 2; MoCA score: 11).
Conclusion(s): Our patients showed very different post-HD plasma-to-CSF gradients. Theoretically, the positive gradient in patient B would favor intradialytic brain swelling. Patient B showed impaired neurological testing results which are not related to patient's pre-existing neurological conditions. We can only speculate if and to what extent trans-BBB water movements driven by dialytic urea dynamics may have impacted the patient's cognitive functions?. We believe that patient-specific levels of osmotic stress need to be considered when developing neuro-protective HD technologies

Background: Hemodialysis (HD) can reduce amyloid-beta (Abeta) species in wholebody circulation by 30 to 50%. Due to the dynamic exchange of Abeta between the brain and the blood, we hypothesized that HD might lower Abeta levels in the cerebrospinal fluid (CSF).
Method(s): In a dialysis network with over 160,000 patients, we identified three maintenance HD patients (age 36+/-9 years) with ventriculo-peritoneal (VP) shunts who were subsequently recruited for this IRB-approved research study. Study subjects were dialyzed on Monday, Wednesday, and Friday. Plasma samples were collected at 6 timepoints during the 3 HD sessions. One subject was withdrawn over safety concern related to the VP shunt tap procedure. Two subjects further underwent VP shunt taps for CSF sample collection before and after the Wednesday and Friday HD sessions, and once on interdialytic days (Tuesday, Thursday). Abeta1-42 and Abeta1-40 were quantified by Neuro 3-Plex SIMOA assays (Quanterix, MA, USA).
Result(s): HD effectively reduced plasma Abeta1-40 by 41% and Abeta1-42 by 34% (Fig 1a and 1b, p < 0.01). In CSF, levels of Abeta increased after Wednesday HD sessions in subject 1 (Abeta1-40: 4.2-fold, Abeta1-42: 5.5-fold) and subject 2 (Abeta1-40 and Abeta1-42: 1.06-fold), while Abeta decreased after Friday HD sessions in both subject 1 (Abeta1-40: 0.1-fold, Abeta1-42: 0.1-fold) and 2 (Abeta1-40: 0.7-fold, Abeta1-42: 0.7-fold) shown in Figure 1c-f.
Conclusion(s): This is the first report of Abeta dynamics in the CSF and plasma of HD patients. While plasma levels were in similar ranges, we found high inter-individual variations of CSF levels. Different plasma-to-CSF ratios after HD may reflect individual brain Abeta pools that are accessed by HD. We corroborate previous reports demonstrating the removal of Abeta from the blood compartment by HD. (Figure Presented)

BACKGROUND:It is estimated that up to 40% of Alzheimer's Disease and Related Dementias cases can be prevented or delayed by addressing modifiable factors including those that influence vascular risk (hypertension, obesity, smoking, physical activity, diabetes). Prevention may be particularly important in the vascular dementia subtypes. Despite the supporting evidence, the rates of medical therapy to reduce vascular risk are not well described. METHOD/METHODS:We assessed the utilization of statins, aspirin, and blood pressure (BP) medications in adults age ≥65 years cared for at NYU Langone Health, as recorded in the electronic health record. We included two cohorts: cohort 1 included patients who were diagnosed with vascular dementia (VaD) at NYU Langone Barlow Center for Memory Evaluation between January 1, 2015 and June 24, 2019. Cohort 2 extended the inclusion to seniors with VD diagnosis by any NYU Langone physician. Definitions for vascular dementia, the covariates assessed, and medications that we included in each category are shown in Tables 1-3. RESULT/RESULTS:We included 419 and 3745 patients in cohort 1 and cohort 2, respectively. Table 4 shows the characteristics and medication adherence in cohorts 1 and 2. In cohort 1, the prescription rates for statins, aspirin, and BP medications were 66%, 66%, 70%. In cohort 2, the rates for statin, aspirin, and BP medications were 56%, 46%, and 65%, respectively. The differences between prescription rates in cohort 1 and 2 for the three medication groups were statistically significant (p<0.05). CONCLUSION/CONCLUSIONS:Our analysis of the utilization of cardiovascular medications among patients with vascular dementia illuminates potential gaps both among patients who receive care at specialty clinics, as well as the overall population with vascular dementia. The rates of medication utilization are higher for patients under the care of cognitive neurologists. Electronic health records can help identify large cohorts of patients who may benefit from improved access to preventative measures including cardiovascular medications.