Faculty Bibliography

OBJECTIVES/OBJECTIVE:Hyponatremia occurs in up to 30% of patients with pneumonia and is associated with increased morbidity and mortality. The prevalence of hyponatremia associated with coronavirus disease 2019 and the impact on outcome is unknown. We aimed to identify the prevalence, predictors, and impact on outcome of mild, moderate, and severe admission hyponatremia compared with normonatremia among coronavirus disease 2019 patients. DESIGN/METHODS:Retrospective, multicenter, observational cohort study. SETTING/METHODS:Four New York City hospitals that are part of the same health network. PATIENTS/METHODS:Hospitalized, laboratory-confirmed adult coronavirus disease 2019 patients admitted between March 1, 2020, and May 13, 2020. INTERVENTIONS/METHODS:None. MEASUREMENTS AND MAIN RESULTS/RESULTS:Hyponatremia was categorized as mild (sodium: 130-134 mmol/L), moderate (sodium: 121-129 mmol/L), or severe (sodium: ≤ 120 mmol/L) versus normonatremia (135-145 mmol/L). The primary outcome was the association of increasing severity of hyponatremia and in-hospital mortality assessed using multivariable logistic regression analysis. Secondary outcomes included encephalopathy, acute renal failure, mechanical ventilation, and discharge home compared across sodium levels using Kruskal-Wallis and chi-square tests. In exploratory analysis, the association of sodium levels and interleukin-6 levels (which has been linked to nonosmotic release of vasopressin) was assessed. Among 4,645 patient encounters, hyponatremia (sodium < 135 mmol/L) occurred in 1,373 (30%) and 374 of 1,373 (27%) required invasive mechanical ventilation. Mild, moderate, and severe hyponatremia occurred in 1,032 (22%), 305 (7%), and 36 (1%) patients, respectively. Each level of worsening hyponatremia conferred 43% increased odds of in-hospital death after adjusting for age, gender, race, body mass index, past medical history, admission laboratory abnormalities, admission Sequential Organ Failure Assessment score, renal failure, encephalopathy, and mechanical ventilation (adjusted odds ratio, 1.43; 95% CI, 1.08-1.88; p = 0.012). Increasing severity of hyponatremia was associated with encephalopathy, mechanical ventilation, and decreased probability of discharge home (all p < 0.001). Higher interleukin-6 levels correlated with lower sodium levels (p = 0.017). CONCLUSIONS:Hyponatremia occurred in nearly a third of coronavirus disease 2019 patients, was an independent predictor of in-hospital mortality, and was associated with increased risk of encephalopathy and mechanical ventilation.

Early detection and diagnosis of neurodegenerative diseases has been hampered by the lack of sensitive testing. Real-time quaking induced conversion (RT-QuIC) has been used for the early and sensitive detection of prion-induced neurologic disease, and has more recently been adapted to detect misfolded alpha-synuclein and tau as biomarkers for neurodegenerative disease. Here we use full-length recombinant tau substrates to detect tau seeding activity in Alzheimer's disease and other human tauopathies.

Identifying cerebral vulnerability in late life may help prevent or slow the progression of aging-related chronic diseases. However, non-invasive biomarkers aimed at detecting subclinical cerebral changes in the elderly are lacking. Here, we have examined the potential of plasma total tau (t-tau) for identifying cerebral and cognitive deficits in normal elderly subjects. Patterns of cortical thickness and cortical glucose metabolism were used as outcomes of cerebral vulnerability. We found that increased plasma t-tau levels were associated with widespread reductions of cortical glucose uptake, thinning of the temporal lobe, and memory deficits. Importantly, tau-related reductions of glucose consumption in the orbitofrontal cortex emerged as a determining factor of the relationship between cortical thinning and memory loss. Together, these results support the view that plasma t-tau may serve to identify subclinical cerebral and cognitive deficits in normal aging, allowing detection of individuals at risk for developing aging-related neurodegenerative conditions.

Background: Zinc impairs replication of RNA viruses such as SARS-CoV-1, and may be effective against SARS-CoV-2. However, to achieve adequate intracellular zinc levels, administration with an ionophore, which increases intracellular zinc levels, may be necessary. We evaluated the impact of zinc with an ionophore (Zn+ionophore) on COVID-19 in-hospital mortality rates. Methods: A multicenter cohort study was conducted of 3,473 adult hospitalized patients with reverse-transcriptase-polymerase-chain-reaction (RT-PCR) positive SARS-CoV-2 infection admitted to four New York City hospitals between March 10 through May 20, 2020. Exclusion criteria were: death or discharge within 24h, comfort-care status, clinical trial enrollment, treatment with an IL-6 inhibitor or remdesivir. Patients who received Zn+ionophore were compared to patients who did not using multivariable time-dependent cox proportional hazards models for time to in-hospital death adjusting for confounders including age, sex, race, BMI, diabetes, week of admission, hospital location, sequential organ failure assessment (SOFA) score, intubation, acute renal failure, neurological events, treatment with corticosteroids, azithromycin or lopinavir/ritonavir and the propensity score of receiving Zn+ionophore. A sensitivity analysis was performed using a propensity score-matched cohort of patients who did or did not receive Zn+ionophore matched by age, sex and ventilator status. Results: Among 3,473 patients (median age 64, 1947 [56%] male, 522 [15%] ventilated, 545[16%] died), 1,006 (29%) received Zn+ionophore. Zn+ionophore was associated with a 24% reduced risk of in-hospital mortality (12% of those who received Zn+ionophore died versus 17% who did not; adjusted Hazard Ratio [aHR] 0.76, 95% CI 0.60-0.96, P=0.023). More patients who received Zn+ionophore were discharged home (72% Zn+ionophore vs 67% no Zn+ionophore, P=0.003) Neither Zn nor the ionophore alone were associated with decreased mortality rates. Propensity score-matched sensitivity analysis (N=1356) validated these results (Zn+ionophore aHR for mortality 0.63, 95%CI 0.44-0.91, P=0.015). There were no significant interactions for Zn+ionophore with other COVID-19 specific medications. Conclusions: Zinc with an ionophore was associated with increased rates of discharge home and a 24% reduced risk of in-hospital mortality among COVID-19 patients, while neither zinc alone nor the ionophore alone reduced mortality. Further randomized trials are warranted.

Accumulation of phosphorylated tau is a key pathological feature of Alzheimer's disease. Phosphorylated tau accumulation causes synaptic impairment, neuronal dysfunction and formation of neurofibrillary tangles. The pathological actions of phosphorylated tau are mediated by surrounding neuronal proteins; however, a comprehensive understanding of the proteins that phosphorylated tau interacts with in Alzheimer's disease is surprisingly limited. Therefore, the aim of this study was to determine the phosphorylated tau interactome. To this end, we used two complementary proteomics approaches: (i) quantitative proteomics was performed on neurofibrillary tangles microdissected from patients with advanced Alzheimer's disease; and (ii) affinity purification-mass spectrometry was used to identify which of these proteins specifically bound to phosphorylated tau. We identified 542 proteins in neurofibrillary tangles. This included the abundant detection of many proteins known to be present in neurofibrillary tangles such as tau, ubiquitin, neurofilament proteins and apolipoprotein E. Affinity purification-mass spectrometry confirmed that 75 proteins present in neurofibrillary tangles interacted with PHF1-immunoreactive phosphorylated tau. Twenty-nine of these proteins have been previously associated with phosphorylated tau, therefore validating our proteomic approach. More importantly, 34 proteins had previously been associated with total tau, but not yet linked directly to phosphorylated tau (e.g. synaptic protein VAMP2, vacuolar-ATPase subunit ATP6V0D1); therefore, we provide new evidence that they directly interact with phosphorylated tau in Alzheimer's disease. In addition, we also identified 12 novel proteins, not previously known to be physiologically or pathologically associated with tau (e.g. RNA binding protein HNRNPA1). Network analysis showed that the phosphorylated tau interactome was enriched in proteins involved in the protein ubiquitination pathway and phagosome maturation. Importantly, we were able to pinpoint specific proteins that phosphorylated tau interacts with in these pathways for the first time, therefore providing novel potential pathogenic mechanisms that can be explored in future studies. Combined, our results reveal new potential drug targets for the treatment of tauopathies and provide insight into how phosphorylated tau mediates its toxicity in Alzheimer's disease.

ADAMTSs (a disintegrin and metalloproteinase with thrombospondin motifs) are secreted metalloproteinases that play a major role in the assembly and degradation of the extracellular matrix (ECM). In this study, we show that ADAMTS18, produced by the epithelial cells of distal airways and mesenchymal cells in lung apex at early embryonic stages, serves as a morphogen in lung development. ADAMTS18 deficiency leads to reduced number and length of bronchi, tipped lung apexes, and dilated alveoli. These developmental defects worsen lipopolysaccharide-induced acute lung injury and bleomycin-induced lung fibrosis in adult Adamts18-deficient mice. ADAMTS18 deficiency also causes increased levels of fibrillin1 and fibrillin2, bronchial microfibril accumulation, decreased focal adhesion kinase signaling, and disruption of F-actin organization. Our findings indicate that ECM homeostasis mediated by ADAMTS18 is pivotal in airway branching morphogenesis.

Alzheimer's disease (AD) is a neurodegenerative brain disorder associated with relentlessly progressive cognitive impairment and memory loss. AD pathology proceeds for decades before cognitive deficits become clinically apparent, opening a window for preventative therapy. Imbalance of clearance and buildup of amyloid β and phosphorylated tau proteins in the central nervous system is believed to contribute to AD pathogenesis. However, multiple clinical trials of treatments aimed at averting accumulation of these proteins have yielded little success, and there is still no disease-modifying intervention. Here, we discuss current knowledge of AD pathology and treatment with an emphasis on emerging biomarkers and treatment strategies.

PURPOSE OF REVIEW/OBJECTIVE:Primary age-related tauopathy (PART) was recently proposed as a pathologic diagnosis for brains that harbor neurofibrillary tangles (Braak stage ≤ 4) with little, if any, amyloid burden. We sought to review the clinicopathologic findings related to PART. RECENT FINDINGS/RESULTS:Most adult human brains show at least focal tauopathic changes, and the majority of individuals with PART do not progress to dementia. Older age and cognitive impairment correlate with increased Braak stage, and multivariate analyses suggest that the rate of cognitive decline is less than matched patients with Alzheimer disease (AD). It remains unclear whether PART is a distinct tauopathic entity separate from AD or rather represents an earlier histologic stage of AD. Cognitive decline in PART is usually milder than AD and correlates with tauopathic burden. Biomarker and ligand-based radiologic studies will be important to define PART antemortem and prospectively follow its natural history.

BACKGROUND:We have described the clinical stages of the brain aging and Alzheimer's disease (AD) continuum. In terms of the pre-dementia stages of AD, we introduced the terminology "mild cognitive impairment" (MCI) for the first pre-dementia stage and "subjective cognitive decline" (SCD) for the pre-MCI stage. We now report the characteristics of a pre-SCD condition eventuating in likely AD. OBJECTIVE:The aim of this study was to characterize a pre-SCD condition eventuating in AD. METHOD/METHODS:Sixty healthy persons with "no cognitive decline" (NCD) were recruited and 47 were followed (mean baseline age, 64.1 ± 8.9 years; mean follow-up time, 6.7 ± 3.1 years). Outcome was determined at the final assessment prior to 2002 as "decliner," if SCD or worse, or "nondecliner" if NCD. RESULTS:After controlling for age, gender, years of education, and follow-up time, there was a between-group difference in the decline rate (p < 0.001). Also, after controlling for demographic variables and follow-up time, the combinatorial psychometric score was lower at baseline in the future decliners (p = 0.035). Of the 9 psychometric variables, after controlling for demographic variables and follow-up time, 3 were significantly lower at baseline in future decliners. Since AD is known to be age related and all subjects in this study were otherwise healthy, we also did an analysis without controlling for age. The combinatorial psychometric score was highly significantly better at baseline in the future nondecliners than in the future decliners (p = 0.008). CONCLUSION/CONCLUSIONS:This is ostensibly the first study to link psychometric cognitive decline to the subsequent SCD stage of eventual AD.

Purpose of Study Autism spectrum disorders (ASDs) are neurodevelopmental disorders with lifelong consequences and poorly understood pathophysiology. Dysregulated cholesterol metabolism is implicated in ASD etiology. Cholesterol is essential for neuroactive steroid production, myelin sheath formation, and normal brain development. Early postnatal or in utero exposure to the antiepileptic drug valproic acid (VPA), a branched short-chain fatty acid, causes autism-like neural and behavioral deficits in humans and rodents. This study examines the link between VPA and cholesterol deficit in cultured human neurons and microglia. Methods Used SHSY-5Y human neuroblastoma cells and HMC3 human microglial cells were exposed to VPA at 0, 250, 1000 and 5000 muM for 24h, N=3 per condition. Expression of critical genes that regulate cholesterol transport were quantified by RT-PCR using specific primers for each. These include the efflux proteins ABCA1, ABCG1, 27-hydroxylase (27-OHase) and 24-hydroxylase (24-OHase), and the influx scavenger receptor CD36 - all vital for brain cholesterol balance. Expression of these target genes was normalized to concurrently measured GAPDH mRNA levels. Summary of Results In SH-SY5Y neurons, VPA exposure caused a concentration-dependent increase in ABCA1 (P <0.001), ABCG1, 27-OHase (P <0.001) (figure 1), and CD36 (P=0.015). In HMC3, VPA exposure caused a concentration- dependent increase in ABCG1 (80-fold at highest dose, P<=0.001) and 24-OHase (P < 0.001) with a reduction in ABCA-1 (P=0.002) and an increase in CD36 (P<0.001). Conclusions This study shows that VPA has a dramatic hypocholesterolemic effect on two key cell types that compose the developing brain. The net impact of the changes observed in these cholesterol-related genes would be outflow and metabolism. Further, enhanced 27-OHase activity produces an oxysterol metabolite with neurotoxic effects that include downregulating synaptic proteins and decreasing neurite number and length. Together, our results suggest that VPA impairs brain cholesterol homeostasis. A better understanding of the involvement of cholesterol in the mechanisms by which VPA leads to ASDs may translate into novel preventative therapies for this serious disorder