Evidence for a novel neuronal mechanism driving Alzheimer's disease, upstream of amyloid

This perspective offers an alternative to the amyloid hypothesis in the etiology of Alzheimer's disease (AD). We review evidence for a novel signaling mechanism based on a little‐known peptide, T14. T14 could drive neurodegeneration as an aberrantly activated process of plasticity selective to interconnecting subcortical nuclei, the isodendritic core, where cell loss starts at the pre‐symptomatic stages of the disease. Each of these cell groups has the capacity to form T14, which can stimulate production of p‐Tau and β‐amyloid, suggestive of an upstream driver of neurodegeneration. Moreover, results in an animal AD model show that antagonism of T14 with a cyclated variant, NBP14, prevents formation of β‐amyloid, and restores cognitive function to that of wild‐type counterparts. Any diagnostic and/or therapeutic strategy based on T14‐NBP14 awaits validation in clinical trials. However, an understanding of this novel signaling system could bring much‐needed fresh insights into the progression of cell loss underlying AD. Highlights: The possible primary mechanism of neurodegeneration upstream of amyloid. Primary involvement of selectively vulnerable subcortical nuclei, isodendritic core. Bioactive peptide T14 trophic in development but toxic in context of mature brain. Potential for early‐stage biomarker to detect Alzheimer's disease. Effective therapeutic halting neurodegeneration, validated already in 5XFAD mice

Extensive Cutaneous Scalp Angiosarcoma

Angiosarcoma is a cancer that is derived from endothelial cells that line blood vessels and lymphatic channels. Cutaneous angiosarcoma can appear anywhere on the skin and the clinical presentation is highly variable. Most cases appear on the scalp and face de novo. Our case describes a 91-year-old female with cutaneous scalp angiosarcoma. Our case serves to remind physicians that an abnormal skin finding in older adults should raise their index of suspicion for angiosarcoma and an early biopsy should be performed

Etnogerontología. La posición de la Sociedad Americana de Geriatría sobre etnogeriatría

Las minorías de ancianos en los Estados Unidos tendrán un crecimiento acelerado en las próximas décadas. Incluyen ancianos de grupos étnicos heterogéneos como negros, hispanos, asiáticos e indígenas americanos. El Comité de Etnogeriatría de la Sociedad Americana de Geriatría, SAG, trabaja en aspectos relacionados con la salud y el bienestar de tales minorías. Se informa la Declaración de Posición en Etnogeriatría de la SAG. La SAG promueve la sensibilidad multicultural, la educación y la investigación interdisciplinaria sobre los factores étnicos que afectan el envejecimiento, la salud y la aparición de enfermedades en las personas mayores. Las minorías de ancianos tienen una alta prevalencia de cuadros clínicos patológicos en edades tempranas que afectan la funcionalidad y calidad de vida de estas personas. También hay barreras lingüísticas o culturales, pobreza, y bajo nivel educativo que disminuyen el acceso al cuidado de la salud. La SAG apoya conocer y superar esos factores que influyen sobre la salud de las minorías de ancianos en América. Older minorities in the United States will have a fast increase in the next decades. They include older people of heterogeneous ethnic groups such as blacks, latins, Asian and Indian Americans. The Ethnogeriatrics Committee of the American Geriatrics Society works on aspects related to health and wellbeing of older minorities. The Position Statement on Ethnogeriatrics of the AGS is given. The AGS promoves cultural sensibility, interdisciplinary education and research on ethnic factors that affect aging, health and presentation of diseases in older persons. Older minorities have a high prevalence of diseases at early ages that affect their function and quality of life. They also have culture or language barriers, poverty and low education that decrease their access to health care. The AGS supports knowledge and improvement of these factors that affect health of older minority Americans

A blinded clinical study using a subepidermal moisture biocapacitance measurement device for early detection of pressure injuries.

This study aimed to evaluate the sensitivity and specificity of subepidermal moisture (SEM), a biomarker employed for early detection of pressure injuries (PI), compared to the Gold Standard of clinical skin and tissue assessment (STA), and to characterize the timing of SEM changes relative to the diagnosis of a PI. This blinded, longitudinal, prospective clinical study enrolled 189 patients (n = 182 in intent-to-treat [ITT]) at acute and post-acute sites (9 USA, 3 UK). Data were collected from patients\u27 heels and sacrums using a biocapacitance measurement device beginning at admission and continuing for a minimum of 6 days to: (a) the patient developing a PI, (b) discharge from care, or (c) a maximum of 21 days. Standard of care clinical interventions prevailed, uninterrupted. Principal investigators oversaw the study at each site. Blinded Generalists gathered SEM data, and blinded Specialists diagnosed the presence or absence of PIs. Of the ITT population, 26.4% developed a PI during the study; 66.7% classified as Stage 1 injuries, 23% deep tissue injuries, the remaining being Stage 2 or Unstageable. Sensitivity was 87.5% (95% CI: 74.8%-95.3%) and specificity was 32.9% (95% CI: 28.3%-37.8%). Area under the receiver operating characteristic curve (AUC) was 0.6713 (95% CI 0.5969-0.7457, P \u3c .001). SEM changes were observed 4.7 (± 2.4 days) earlier than diagnosis of a PI via STA alone. Latency between the SEM biomarker and later onset of a PI, in combination with standard of care interventions administered to at-risk patients, may have confounded specificity. Aggregate SEM sensitivity and specificity and 67.13% AUC exceeded that of clinical judgment alone. While acknowledging specificity limitations, these data suggest that SEM biocapacitance measures can complement STAs, facilitate earlier identification of the risk of specific anatomies developing PIs, and inform earlier anatomy-specific intervention decisions than STAs alone. Future work should include cost-consequence analyses of SEM informed interventions

Use of Tethered Enzymes as a Platform Technology for Rapid Analyte Detection

<div><p>Background</p><p>Rapid diagnosis for time-sensitive illnesses such as stroke, cardiac arrest, and septic shock is essential for successful treatment. Much attention has therefore focused on new strategies for rapid and objective diagnosis, such as Point-of-Care Tests (PoCT) for blood biomarkers. Here we use a biomimicry-based approach to demonstrate a new diagnostic platform, based on enzymes tethered to nanoparticles (NPs). As proof of principle, we use oriented immobilization of pyruvate kinase (PK) and luciferase (Luc) on silica NPs to achieve rapid and sensitive detection of neuron-specific enolase (NSE), a clinically relevant biomarker for multiple diseases ranging from acute brain injuries to lung cancer. We hypothesize that an approach capitalizing on the speed and catalytic nature of enzymatic reactions would enable fast and sensitive biomarker detection, suitable for PoCT devices.</p><p>Methods and findings</p><p>We performed in-vitro, animal model, and human subject studies. First, the efficiency of coupled enzyme activities when tethered to NPs versus when in solution was tested, demonstrating a highly sensitive and rapid detection of physiological and pathological concentrations of NSE. Next, in rat stroke models the enzyme-based assay was able in minutes to show a statistically significant increase in NSE levels in samples taken 1 hour before and 0, 1, 3 and 6 hours after occlusion of the distal middle cerebral artery. Finally, using the tethered enzyme assay for detection of NSE in samples from 20 geriatric human patients, we show that our data match well (r = 0.815) with the current gold standard for biomarker detection, ELISA—with a major difference being that we achieve detection in 10 minutes as opposed to the several hours required for traditional ELISA.</p><p>Conclusions</p><p>Oriented enzyme immobilization conferred more efficient coupled activity, and thus higher assay sensitivity, than non-tethered enzymes. Together, our findings provide proof of concept for using oriented immobilization of active enzymes on NPs as the basis for a highly rapid and sensitive biomarker detection platform. This addresses a key challenge in developing a PoCT platform for time sensitive and difficult to diagnose pathologies.</p></div

Using the tethered enzyme assay for rapid detection of NSE in human subjects.

<p><b>A)</b> Representative data as measured from a total of nine wells per subject (triplicate measurements of negative control with no 2PG; the test sample with 2PG; and positive control wells with 2PG and enolase (Eno); mean±STDEV) For calculation of NSE levels, slopes of averaged curves were calculated for the first 0.5–10 minutes of the enzymatic reactions (indicated by the red linear fit in between the dashed lines), then test wells were normalized to positive and negative wells (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0142326#sec007" target="_blank">methods</a> section). <b>B)</b> High correlation was found between NSE measurements by ELISA (ng/ml) vs. TET assay (AU represents the normalization of test reaction to the negative and positive reactions, as illustrated in A and described in the methods section) as of the human plasma samples. Line indicates best fit. Pearson’s r = 0.815, n = 20.</p

Immobilization of PK and Luc on NPs improves coupled reaction efficiency.

<p><b>A)</b> Schematic illustration of the 6XHis-Si tag fusion constructs for PK or Luc. <b>B)</b> Schematic representation of the PK-Luc coupled reaction as used in the experiments described in C. <b>C)</b> PK and Luc coupled activity was assayed in 4 combinations as indicated by the color coded schematic illustrations: black- (NP-PK) + (NP-Luc), blue- (NP-PK) + (soluble Luc), green- (NP-Luc) + (soluble PK) or red- (soluble PK + soluble Luc). All combinations included equivalent amounts of PK and Luc. Maximal coupled reaction efficiency, as calculated from normalizing each time point data to t₀ (indicating the ratio of luminescence generated at each time point relative to the luminescence at the beginning of the reaction) and subtraction of the negative control well (no PEP, corresponding to the background luminescence signal), was observed when both PK and Luc were immobilized on NPs (each condition was tested in triplicates; data shown represents 3 individual experiments; AVG±STDEV).</p

Using NP-PK and NP-Luc for rapid detection of NSE in a rat model for stroke.

<p><b>A)</b> Fluoro Jade-C staining for measurement of damaged brain tissue volume. The presence and absence of FJC-labeled degenerative neurons were imaged with epifluorescence under 20x magnification using filters for FITC. (a) Region with abundant FJC staining (bright cells) on lesioned side. (b) Region at the edge of FJC staining. (c) Region that is contralateral to (a) that did not show any FJC staining. Dotted line in B and low magnification inset indicates manually-mapped border between FJC positive and negative areas. <b>B)</b> FJC staining in control brain section. (a) and (b) are in area of craniectomy. <b>C-D)</b> Individual rat data (C-stroke and D-control) for NSE measurements at each time point (grayscale lines indicate data points for individual animals, line with symbol indicates the mean±standard deviation) as performed by tethered PK and Luc assay, and normalized to time point -1 hour. Plasma samples were collected from stroke induced or control rats pre (-1 hr), and post occlusion (0, 1, 3 and 6 hr). The mean slope of the trend (dashed line) was calculated averaging individual slopes in each group (stroke = 0.26 with 0.95 confidence interval, control = -0.02 with 0.38 confidence interval). <b>E</b>) Summary of rat stroke model experiments showing a statistically significant increase in NSE plasma levels in stroke (blue bars) vs. control (red bars) rats as soon as 1 hour post occlusion. <b>F)</b> Measurements of NSE in plasma from rats using ELISA showed elevated levels in stroke compared to control rats at the last time point (6 hr post-occlusion). P values– 0.05<*<0.1, 0.01<**<0.05. Data from 10 rats were included in our analysis, with the exclusion of 3 hour and 6 hour time points for one control animal that died (at 2 hour mark), and a 6 hour time point for a stroke animal which died and was found to have a large hemorrhage at the base of the brain.</p

Improved sensitivity for enolase detection via its enzymatic activity when using tethered PK and Luc.

<p><b>A)</b> Comparison of the detection sensitivity for enolase activity (Eno) as measured by NP-PK + NP-Luc (red) vs. PK + Luc in solution (blue). Increasing concentrations of Eno were added to immobilized or freely diffusing enzymes in reaction buffer. Luminescence was detected and integrated over 10 minutes at RT and plotted against Eno final unit amount (lines were added to guide the eye). The inset shows the ratio of the enzymes’ activities on NPs versus in solution as a function of units of ENO. Data presented as AVG±STDEV. <b>B)</b> NSE detection via PK and Luc coupled activity was performed as indicated in the schematic illustration (right). His-Si-PK and His-Si-Luc were immobilized on 500 nm NPs and mixed with reaction buffer supplemented with increasing concentrations of human NSE. Luminescence readout was normalized to t0 (first read) values and plotted as a function of time. Then, the luminescent signal was integrated for first 10 minutes, and a reading from the zero NSE well was subtracted from the collected signal. The sensitivity of the tethered enzyme assay was about 5 times higher than the reported average physiological NSE blood concentration (8.7 ± 3.9 ng/ml [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0142326#pone.0142326.ref024" target="_blank">24</a>]). P values were calculated using student’s t-test for comparisons between NSE concentrations; values marked with ^<b>#</b>P were calculated for significance when compared against 0 ng/ml NSE.</p