Plasma and cerebrospinal fluid ABeta42 for the differential diagnosis of Alzheimer's disease dementia in participants diagnosed with any dementia subtype in a specialist care setting

BackgroundDementia is a syndrome that comprises many differing pathologies, including Alzheimer's disease dementia (ADD), vascular dementia (VaD) and frontotemporal dementia (FTD). People may benefit from knowing the type of dementia they live with, as this could inform prognosis and may allow for tailored treatment. Beta-amyloid (1-42) (ABeta42) is a protein which decreases in both the plasma and cerebrospinal fluid (CSF) of people living with ADD, when compared to people with no dementia. However, it is not clear if changes in ABeta42 are specific to ADD or if they are also seen in other types of dementia. It is possible that ABeta42 could help differentiate ADD from other dementia subtypes.ObjectivesTo determine the accuracy of plasma and CSF ABeta42 for distinguishing ADD from other dementia subtypes in people who meet the criteria for a dementia syndrome.Search methodsWe searched MEDLINE, and nine other databases up to 18 February 2020. We checked reference lists of any relevant systematic reviews to identify additional studies.Selection criteriaWe considered cross-sectional studies that differentiated people with ADD from other dementia subtypes. Eligible studies required measurement of participant plasma or CSF ABeta42 levels and clinical assessment for dementia subtype.Data collection and analysisSeven review authors working independently screened the titles and abstracts generated by the searches. We collected data on study characteristics and test accuracy. We used the second version of the 'Quality Assessment of Diagnostic Accuracy Studies' (QUADAS-2) tool to assess internal and external validity of results. We extracted data into 2 x 2 tables, cross-tabulating index test results (ABeta42) with the reference standard (diagnostic criteria for each dementia subtype). We performed meta-analyses using bivariate, random-effects models. We calculated pooled estimates of sensitivity, specificity, positive predictive values, positive and negative likelihood ratios, and corresponding 95% confidence intervals (CIs). In the primary analysis, we assessed accuracy of plasma or CSF ABeta42 for distinguishing ADD from other mixed dementia types (non-ADD). We then assessed accuracy of ABeta42 for differentiating ADD from specific dementia types: VaD, FTD, dementia with Lewy bodies (DLB), alcohol-related cognitive disorder (ARCD), Creutzfeldt-Jakob disease (CJD) and normal pressure hydrocephalus (NPH). To determine test-positive cases, we used the ABeta42 thresholds employed in the respective primary studies. We then performed sensitivity analyses restricted to those studies that used common thresholds for ABeta42.Main resultsWe identified 39 studies (5000 participants) that used CSF ABeta42 levels to differentiate ADD from other subtypes of dementia. No studies of plasma ABeta42 met the inclusion criteria. No studies were rated as low risk of bias across all QUADAS-2 domains. High risk of bias was found predominantly in the domains of patient selection (28 studies) and index test (25 studies). The pooled estimates for differentiating ADD from other dementia subtypes were as follows: ADD from non-ADD: sensitivity 79% (95% CI 0.73 to 0.85), specificity 60% (95% CI 0.52 to 0.67), 13 studies, 1704 participants, 880 participants with ADD; ADD from VaD: sensitivity 79% (95% CI 0.75 to 0.83), specificity 69% (95% CI 0.55 to 0.81), 11 studies, 1151 participants, 941 participants with ADD; ADD from FTD: sensitivity 85% (95% CI 0.79 to 0.89), specificity 72% (95% CI 0.55 to 0.84), 17 studies, 1948 participants, 1371 participants with ADD; ADD from DLB: sensitivity 76% (95% CI 0.69 to 0.82), specificity 67% (95% CI 0.52 to 0.79), nine studies, 1929 participants, 1521 participants with ADD. Across all dementia subtypes, sensitivity was greater than specificity, and the balance of sensitivity and specificity was dependent on the threshold used to define test positivity.Authors' conclusionsOur review indicates that measuring ABeta42 levels in CSF may help differentiate ADD from other dementia subtypes, but the test is imperfect and tends to misdiagnose those with non-ADD as having ADD. We would caution against the use of CSF ABeta42 alone for dementia classification. However, ABeta42 may have value as an adjunct to a full clinical assessment, to aid dementia diagnosis

TREM-1 expression on neutrophils and monocytes of septic patients: relation to the underlying infection and the implicated pathogen

<p>Abstract</p> <p>Background</p> <p>Current knowledge on the exact ligand causing expression of TREM-1 on neutrophils and monocytes is limited. The present study aimed at the role of underlying infection and of the causative pathogen in the expression of TREM-1 in sepsis.</p> <p>Methods</p> <p>Peripheral venous blood was sampled from 125 patients with sepsis and 88 with severe sepsis/septic shock. The causative pathogen was isolated in 91 patients. Patients were suffering from acute pyelonephritis, community-acquired pneumonia (CAP), intra-abdominal infections (IAIs), primary bacteremia and ventilator-associated pneumonia or hospital-acquired pneumonia (VAP/HAP). Blood monocytes and neutrophils were isolated. Flow cytometry was used to estimate the TREM-1 expression from septic patients.</p> <p>Results</p> <p>Within patients bearing intrabdominal infections, expression of TREM-1 was significantly lower on neutrophils and on monocytes at severe sepsis/shock than at sepsis. That was also the case for severe sepsis/shock developed in the field of VAP/HAP. Among patients who suffered infections by Gram-negative community-acquired pathogens or among patients who suffered polymicrobial infections, expression of TREM-1 on monocytes was significantly lower at the stage of severe sepsis/shock than at the stage of sepsis.</p> <p>Conclusions</p> <p>Decrease of the expression of TREM-1 on the membrane of monocytes and neutrophils upon transition from sepsis to severe sepsis/septic shock depends on the underlying type of infection and the causative pathogen.</p

The role of asymmetric dimethylarginine in murine pregnancy and its link to pregnancy-induced hypertension

Globally, preeclampsia accounts for approximately 10% of pregnancy-related deaths. In the United States, the incidence of the disease has risen dramatically over the last two decades. Pharmacological interventions for the management of preeclampsia are very limited; premature delivery is the only option, often resulting in life-long disabilities. Association studies indicate increased levels of asymmetric dimethylarginine (ADMA) in preeclamptic patients, prior to clinical manifestation. ADMA is a negative regulator of the nitric oxide signaling pathway with high levels leading to systemic hypertension in vivo. Inhibition of the enzyme dimethylarginine dimethylaminohydrolase (DDAH) leads to accumulation of ADMA, suggesting that the latter is actively metabolized by DDAH. We sought to assess the impact of elevated ADMA levels on haemodynamic adaptations during pregnancy and fetoplacental development in vivo through genetic DDAH1 manipulation. Clinical studies have shown that paternal genes increase preeclampsia susceptibility. We hypothesised that a systemic increase in maternal AMDA would lead to a hypertensive response during gestation, mediated by the fetus. In order to test the above hypothesis, two distinct mouse models were generated; a DDAH1 null model and a fetal-specific DDAH1 knockout model. DDAH1 deletion led to accumulation of plasma ADMA, sFlt-1 and sEng during late gestation accompanied by a significant increase in systemic blood pressure. Fetal-specific DDAH1 deletion led to a small but significant increase in maternal circulating ADMA and elevated blood pressure around parturition. Given the above findings, we hypothesized that paternally- inherited single nucleotide polymorphisms (SNPs) with the ddah1 locus might alter the susceptibility to preeclampsia. To test this hypothesis, the frequency of several SNPs was estimated and compared between babies from preeclamptic and normotensive pregnancies. No correlation was identified for any of the variants analysed, suggesting that paternal DDAH1 does not alter the risk of preeclampsia. It is worth mentioning that the analysis was done in a small cohort; as such, additional studies are needed in order to draw safe conclusions.Open Acces

Backbone and side chain NMR assignments of the H-NOX domain from Nostoc sp. in complex with BAY58-2667 (cinaciguat)

Soluble guanylate cyclase (sGC) enzyme is activated by the gaseous signaling agent nitric oxide (NO) and triggers the conversion of GTP (guanosine 5′-triphosphate) to cGMP (cyclic guanylyl monophosphate). It contains the heme binding H-NOX (heme- nitric oxide/oxygen binding) domain which serves as the sensor of NO and it is highly conserved across eukaryotes and bacteria as well. Many research studies focus on the synthesis of chemical compounds bearing possible therapeutic action, which mimic the heme moiety and activate the sGC enzyme. In this study, we report a preliminary solution NMR (Nuclear Magnetic Resonance) study of the H-NOX domain from Nostoc sp. cyanobacterium in complex with the chemical sGC activator cinaciguat (BAY58-2667). An almost complete sequence-specific assignment of its 1H, 15N and 13C resonances was obtained and its secondary structure predicted by TALOS+

Replacement of heme by soluble guanylate cyclase (sGC) activators abolishes heme-nitric oxide/oxygen (H-NOX) domain structural plasticity

The gasotransmitter nitric oxide (NO) is a critical endogenous regulator of homeostasis, in major part via the generation of cGMP (cyclic guanosine monophosphate) from GTP (guanosine triphosphate) by NO’s main physiological receptor, the soluble guanylate cyclase (sGC). sGC is a heterodimer, composed of an alpha 1 and a beta 1 subunit, of which the latter contains the heme-nitric oxide/oxygen (H-NOX) domain, responsible for NO recognition, binding and signal initiation. The NO/sGC/cGMP axis is dysfunctional in a variety of diseases, including hypertension and heart failure, especially since oxidative stress results in heme oxidation, sGC unresponsiveness to NO and subsequent degradation. As a central player in this axis, sGC is the focus of intense research efforts aiming to develop therapeutic molecules that enhance its activity. A class of drugs named sGC “activators” aim to replace the oxidized heme of the H-NOX domain, thus stabilizing the enzyme and restoring its activity. Although numerous studies outline the pharmacology and binding behavior of these compounds, the static 3D models available so far do not allow a satisfactory understanding of the structural basis of sGC’s activation mechanism by these drugs. Herein, application NMR describes different conformational states during the replacement of the heme by a sGC activators. We show that the two sGC activators (BAY 58-2667 and BAY 60-2770) significantly decrease the conformational plasticity of the recombinant H-NOX protein domain of Nostoc sp. cyanobacterium, rendering it a lot more rigid compared to the heme-occupied H-NOX. NMR methodology also reveals, for the first time, a surprising bi-directional competition between reduced heme and these compounds, pointing to a highly dynamic regulation of the H-NOX domain. This competitive, bi-directional mode of interaction is also confirmed by monitoring cGMP generation in A7r5 vascular smooth muscle cells by these activators. We show that, surprisingly, heme’s redox state impacts differently the bioactivity of these two structurally similar compounds. In all, by NMR-based and functional approaches we contribute unique experimental insight into the dynamic interaction of sGC activators with the H-NOX domain and its dependence on the heme redox status, with the ultimate goal to permit a better design of such therapeutically important molecules

The imprinted Igf2-Igf2r axis is critical for matching placental microvasculature expansion to fetal growth.

In all eutherian mammals, growth of the fetus is dependent upon a functional placenta, but whether and how the latter adapts to putative fetal signals is currently unknown. Here, we demonstrate, through fetal, endothelial, hematopoietic, and trophoblast-specific genetic manipulations in the mouse, that endothelial and fetus-derived IGF2 is required for the continuous expansion of the feto-placental microvasculature in late pregnancy. The angiocrine effects of IGF2 on placental microvasculature expansion are mediated, in part, through IGF2R and angiopoietin-Tie2/TEK signaling. Additionally, IGF2 exerts IGF2R-ERK1/2-dependent pro-proliferative and angiogenic effects on primary feto-placental endothelial cells ex vivo. Endothelial and fetus-derived IGF2 also plays an important role in trophoblast morphogenesis, acting through Gcm1 and Synb. Thus, our study reveals a direct role for the imprinted Igf2-Igf2r axis on matching placental development to fetal growth and establishes the principle that hormone-like signals from the fetus play important roles in controlling placental microvasculature and trophoblast morphogenesis.This work was supported by Biotechnology and Biological Sciences Research Council (grant BB/H003312/1 to M.C.), Medical Research Council (MRC_MC_UU_12012/4 to M.C.; MRC_MC_UU_12012/5 to the MRC Metabolic Diseases Unit; MR/R022690/1 to A.N.S-P.), Spanish Ministry of Science and Innovation (RYC-2019-026956 and PID2020-114459RA-I00 to V.P-G.), Wellcome Trust (Sir Henry Wellcome Postdoctoral Fellowship 220456/Z/20/Z to J.L-T.), Royal Society (Dorothy Hodgkin Research Fellowship grant DH130036 to A.N.S-P.), Centre for Trophoblast Research and the NIHR Cambridge BRC Cell Phenotyping Hub

COVID-19-Associated Pulmonary Aspergillosis (CAPA) in Northern Greece during 2020–2022: A Comparative Study According to the Main Consensus Criteria and Definitions

Coronavirus disease 2019 (COVID-19)-associated pulmonary aspergillosis (CAPA) has emerged as an important complication among patients with acute respiratory failure due to SARS-CoV-2 infection. Almost 2.5 years since the start of the COVID-19 pandemic, it continues to raise concerns as an extra factor that contributes to increased mortality, which is mostly because its diagnosis and management remain challenging. The present study utilises the cases of forty-three patients hospitalised between August 2020 and February 2022 whose information was gathered from ten ICUs and special care units based in northern Greece. The main aim was to describe the gained experience in diagnosing CAPA, according to the implementation of the main existing diagnostic consensus criteria and definitions, and present the different classification of the clinical cases due to the alternative algorithms

Effect of clarithromycin in patients with suspected Gram-negative sepsis: results of a randomized controlled trial

A previous randomized study showed that clarithromycin decreases the risk of death due to ventilator-associated pneumonia and shortens the time until infection resolution. The efficacy of clarithromycin was tested in a larger population with sepsis. Six hundred patients with systemic inflammatory response syndrome due to acute pyelonephritis, acute intra-abdominal infections or primary Gram-negative bacteraemia were enrolled in a double-blind, randomized, multicentre trial. Clarithromycin (1 g) was administered intravenously once daily for 4 days consecutively in 302 patients; another 298 patients were treated with placebo. Mortality was the primary outcome; resolution of infection and hospitalization costs were the secondary outcomes. The groups were well matched for demographics, disease severity, microbiology and appropriateness of the administered antimicrobials. Overall 28 day mortality was 17.1 (51 deaths) in the placebo arm and 18.5 (56 deaths) in the clarithromycin arm (P0.671). Nineteen out of 26 placebo-treated patients with septic shock and multiple organ dysfunctions died (73.1) compared with 15 out of 28 clarithromycin-treated patients (53.6, P0.020). The median time until resolution of infection was 5 days in both arms. In the subgroup with severe sepsis/shock, this was 10 days in the placebo arm and 6 days in the clarithromycin arm (P0.037). The cost of hospitalization was lower after treatment with clarithromycin (P0.044). Serious adverse events were observed in 1.3 and 0.7 of placebo- and clarithromycin-treated patients, respectively (P0.502). Intravenous clarithromycin did not affect overall mortality; however, administration shortened the time to resolution of infection and decreased the hospitalization costs