Presynaptic BDNF Promotes Postsynaptic Long-Term Potentiation in the Dorsal Striatum

Brain-Derived Neurotrophic Factor (BDNF) facilitates the formation of long-term potentiation (LTP) in hippocampus but whether this involves release from pre- vs. post- synaptic pools is unclear. We therefore tested if BDNF is essential for LTP in dorsal striatum, a structure in which the neurotrophin is present only in afferent terminals. Whole cell recordings were collected from medium spiny neurons in striatal slices prepared from adult mice. High frequency stimulation (HFS) of neocortical afferents produced a rapid and stable NMDA receptor-dependent potentiation. The ratio of AMPA to NMDA receptor-mediated components of the EPSPs was substantially increased after inducing potentiation, suggesting that potentiation involved post-synaptic changes. In accord with this, paired pulse response ratios, a measure of transmitter release kinetics, were reduced by elevated calcium but not by LTP. Infusion of the BDNF scavenger TrkB-Fc blocked the formation of potentiation, beginning with the second minute post-HFS, without reducing responses to HFS. These results suggest that presynaptic pools of BDNF can act within 2 minutes of HFS to support the formation of a post-synaptic form of LTP in striatum

Change of right heart size and function by long-term therapy with riociguat in patients with pulmonary arterial hypertension and chronic thromboembolic pulmonary hypertension

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Trends in COVID-19-associated mortality in patients with pulmonary hypertension: a COMPERA analysis

In patients with pulmonary hypertension, the mortality rate associated with COVID-19 has declined sharply with the emergence of the Omicron variants https://bit.ly/42OMsf

LTP Induction Translocates Cortactin at Distant Synapses in Wild-Type But Not Fmr1 Knock-Out Mice

Stabilization of long-term potentiation (LTP) depends on reorganization of the dendritic spine actin cytoskeleton. The present study tested whether this involves activity-driven effects on the actin-regulatory protein cortactin, and whether such effects are disturbed in the Fmr1 knock-out (KO) model of fragile X syndrome, in which stabilization of both actin filaments and LTP is impaired. LTP induced by theta burst stimulation (TBS) in hippocampal slices from wild-type mice was associated with rapid, broadly distributed, and NMDA receptor-dependent decreases in synapse-associated cortactin. The reduction in cortactin content was blocked by blebbistatin, while basal levels were reduced by nocodazole, indicating that cortactin's movements into and away from synapses are regulated by microtubule and actomyosin motors, respectively. These results further suggest that synapse-specific LTP influences cytoskeletal elements at distant connections. The rapid effects of TBS on synaptic cortactin content were absent in Fmr1 KOs as was evidence for activity-driven phosphorylation of the protein or its upstream kinase, ERK1/2. Phosphorylation regulates cortactin's interactions with actin, and coprecipitation of the two proteins was reduced in the KOs. We propose that, in the KOs, excessive basal phosphorylation of ERK1/2 disrupts its interactions with cortactin, thereby blocking the latter protein's use of actomyosin transport systems. These impairments are predicted to compromise the response of the subsynaptic cytoskeleton to learning-related afferent activity, both locally and at distant sites

Toward a common methodological framework for the sampling, extraction, and isotopic analysis of water in the Critical Zone to study vegetation water use

The analysis of the stable isotopic composition of hydrogen and oxygen in water samples from soils and plants can help to identify sources of vegetation water uptake. This approach requires that the heterogeneous nature of plant and soil matrices is carefully accounted for during experimental design, sample collection, water extraction and analyses. The comparability and shortcomings of the different methods for extracting water and analyzing isotopic composition have been discussed in specialized literature. Yet, despite insightful comparisons of extraction methods and benchmarking methodologies of laboratories worldwide, the community still lacks a roadmap to guide sample collection, extraction, and isotopic analyses, and many practical issues for potential users remain unresolved: for example, which (soil or plant) water pool(s) does the extracted water represent? These constitute a hurdle for the implementation of the approach by newcomers. Here, we summarize discussions led in the framework of the COST Action WATSON (“WATer isotopeS in the critical zONe: from groundwater recharge to plant transpiration”—CA19120). We provide guidelines for (1) sampling soil and plant material for isotopic analysis, (2) methods for laboratory or in situ water extraction, and (3) measurements of isotopic composition. We highlight the importance of considering the process chain as a whole, from experimental design to isotopic analysis to minimize biased estimates of the relative contribution of different water sources to plant water uptake. We conclude by acknowledging some of the limitations of this methodology and advice on the collection of key environmental parameters prior to sample collection for isotopic analyses.This article is categorized under: Science of Water > Hydrological Processes Science of Water > Water and Environmental Change Science of Water > Water Extreme

Variation in cartilage T2 and T2* mapping of the wrist: a comparison between 3- and 7-T MRI

Abstract Background To analyze regional variations in T2 and T2* relaxation times in wrist joint cartilage and the triangular fibrocartilage complex (TFCC) at 3 and 7 T and to compare values between field strengths. Methods Twenty-five healthy controls and 25 patients with chronic wrist pain were examined at 3 and 7 T on the same day using T2- and T2*-weighted sequences. Six different regions of interest (ROIs) were evaluated for cartilage and 3 ROIs were evaluated at the TFCC based on manual segmentation. Paired t-tests were used to compare T2 and T2* values between field strengths and between different ROIs. Spearman’s rank correlation was calculated to assess correlations between T2 and T2* time values at 3 and 7 T. Results T2 and T2* time values of the cartilage differed significantly between 3 and 7 T for all ROIs (p ≤ 0.045), with one exception: at the distal lunate, no significant differences in T2 values were observed between field strengths. T2* values differed significantly between 3 and 7 T for all ROIs of the TFCC (p ≤ 0.001). Spearman’s rank correlation between 3 and 7 T ranged from 0.03 to 0.62 for T2 values and from 0.01 to 0.48 for T2* values. T2 and T2* values for cartilage varied across anatomic locations in healthy controls at both 3 and 7 T. Conclusion Quantitative results of T2 and T2* mapping at the wrist differ between field strengths, with poor correlation between 3 and 7 T. Local variations in cartilage T2 and T2* values are observed in healthy individuals. Relevance statement T2 and T2* mapping are feasible for compositional imaging of the TFCC and the cartilage at the wrist at both 3 and 7 T, but the clinical interpretation remains challenging due to differences between field strengths and variations between anatomic locations. Key points •Field strength and anatomic locations influence T2 and T2* values at the wrist. •T2 and T2* values have a poor correlation between 3 and 7 T. •Local reference values are needed for each anatomic location for reliable interpretation. Graphical Abstract </jats:sec

Right ventricular size and function under riociguat in pulmonary arterial hypertension and chronic thromboembolic pulmonary hypertension (the RIVER study)

Background: Riociguat is a soluble guanylate cyclase stimulator approved for pulmonary arterial hypertension (PAH) and chronic thromboembolic pulmonary hypertension (CTPEH). The objective of this study was to evaluate right heart size and function assessed by echocardiography during long term treatment with riociguat. Methods: Patients who started riociguat treatment (1.0–2.5 mg tid) within the trials phase II, PATENT, PATENTplus, EAS, CHEST and continued treatment for 3–12 months were included in this study. Echocardiography was analysed off-line at baseline, after 3, 6 and 12 months by investigators who were blinded to clinical data. Last and baseline observation carried forward method (LOCF, BOCF) were performed as sensitivity analysis. Results: Seventy-one patients (45% PAH, 55% CTEPH; 53.5% female; 60 ± 13 years, mean pulmonary arterial pressure 46 ± 10 mmHg, mean PVR 700 ± 282dynes·sec·cm-5) were included. After 6 months, RA and RV area, RV thickness tricuspid regurgitation velocity showed a significant reduction. After 12 months, patients receiving riociguat therapy showed a significant reduction in right atrial (− 2.6 ± 4.4 cm2, 95% CI -3.84, − 1.33; p &lt; 0.001, n = 49) and right ventricular (RV) area (− 3.5 ± 5.2 cm2, 95% CI -5.1, − 1.9; p &lt; 0.001; n = 44), RV thickness (− 0.76 ± 2.2 mm, 95% CI -1.55, 0.03; n = 32), and a significant increase in TAPSE (2.95 ± 4.78 mm, 95% CI 1.52, 4.39; n = 45) and RV fractional area change (8.12 ± 8.87 mm, 95% CI 4.61, 11.62; n = 27). Both LOCF and BOCF showed similar results but lower effect sizes. Conclusion: Patients under long-term treatment with riociguat show significantly reduced right heart size and improved RV function in PAH and CTEPH. Further controlled prospective studies are needed to confirm these results

Different Rho GTPase–dependent signaling pathways initiate sequential steps in the consolidation of long-term potentiation

The releasable factor adenosine blocks the formation of long-term potentiation (LTP). These experiments used this observation to uncover the synaptic processes that stabilize the potentiation effect. Brief adenosine infusion blocked stimulation-induced actin polymerization within dendritic spines along with LTP itself in control rat hippocampal slices but not in those pretreated with the actin filament stabilizer jasplakinolide. Adenosine also blocked activity-driven phosphorylation of synaptic cofilin but not of synaptic p21-activated kinase (PAK). A search for the upstream origins of these effects showed that adenosine suppressed RhoA activity but only modestly affected Rac and Cdc42. A RhoA kinase (ROCK) inhibitor reproduced adenosine's effects on cofilin phosphorylation, spine actin polymerization, and LTP, whereas a Rac inhibitor did not. However, inhibitors of Rac or PAK did prolong LTP's vulnerability to reversal by latrunculin, a toxin which blocks actin filament assembly. Thus, LTP induction initiates two synaptic signaling cascades: one (RhoA-ROCK-cofilin) leads to actin polymerization, whereas the other (Rac-PAK) stabilizes the newly formed filaments

Idiopathic pulmonary arterial hypertension phenotypes determined by cluster analysis from the COMPERA registry

Funding Information: Marius M. Hoeper has received fees for lectures and/or consultations from Acceleron, Actelion, Bayer, MSD, and Pfizer. Nicola Benjamin has received fees for lectures and/or consultations from Actelion. Ekkehard Grünig has received fees for lectures and/or consultations from Actelion, Bayer, GSK, MSD, United Therapeutics, and Pfizer. Karen M. Olsson has received fees for lectures and/or consultations from Actelion, Bayer, United Therapeutics, GSK, and Pfizer. C. Dario Vizza has received fees from Actelion, Bayer, GSK, MSD, Pfizer, and United Therapeutics Europe. Anton Vonk-Noordegraaf has received fees for lectures and/or consultation from Actelion, Bayer, GSK, and MSD. Oliver Distler has/had a consultancy relationship with and/or has received research funding from 4-D Science, Actelion, Active Biotec, Bayer, Biogen Idec, Boehringer Ingelheim Pharma, BMS, ChemoAb, EpiPharm, Ergonex, espeRare foundation, GSK, Genentech/Roche, Inventiva, Lilly, medac, MedImmune, Mitsubishi Tanabe, Pharmacyclics, Pfizer, Sanofi, Serodapharm, and Sinoxa in the area of potential treatments of scleroderma and its complications including pulmonary arterial hypertension. In addition, Prof Distler has a patent for mir-29 for the treatment of systemic sclerosis licensed. Christian Opitz has received fees from Actelion, Bayer, GSK, Pfizer, and Novartis. J. Simon R. Gibbs has received fees for lectures and/or consultations from Actelion, Bayer, Bellerophon, GSK, MSD, and Pfizer. Marion Delcroix has received fees from Actelion, Bayer, GSK, and MSD. H. Ardeschir Ghofrani has received fees from Actelion, Bayer, Gilead, GSK, MSD, Pfizer, and United Therapeutics. Doerte Huscher has received fees for lectures and consultations from Actelion. David Pittrow has received fees for consultations from Actelion, Biogen, Aspen, Bayer, Boehringer Ingelheim, Daiichi Sankyo, and Sanofi. Stephan Rosenkranz has received fees for lectures and/or consultations from Actelion, Bayer, GSK, Pfizer, Novartis, Gilead, MSD, and United Therapeutics. Martin Claussen reports honoraria for lectures from Boehringer Ingelheim Pharma GmbH and Roche Pharma and for serving on advisory boards from Boehringer Ingelheim, outside the submitted work. Heinrike Wilkens reports personal fees from Boehringer and Roche during the conduct of the study and personal fees from Bayer, Biotest, Actelion, GSK, and Pfizer outside the submitted work. Juergen Behr received grants from Boehringer Ingelheim and personal fees for consultation or lectures from Actelion, Bayer, Boehringer Ingelheim, and Roche. Hubert Wirtz reports personal fees from Boehringer Ingelheim and Roche outside the submitted work. Hening Gall reports personal fees from Actelion, AstraZeneca, Bayer, BMS, GSK, Janssen-Cilag, Lilly, MSD, Novartis, OMT, Pfizer, and United Therapeutics outside the submitted work. Elena Pfeuffer-Jovic reports personal fees from Actelion, Boehringer Ingelheim, Novartis, and OMT outside the submitted work. Laura Scelsi reports personal fees from Actelion, Bayer, and MSD outside the submitted work. Siliva Ulrich reports grants from Swiss National Science Foundation, Zurich Lung, Swiss Lung, and Orpha Swiss, and grants and personal fees from Actelion SA/Johnson & Johnson Switzerland and MSD Switzerland outside the submitted work. The remaining authors have no conflicts of interest to disclose. Funding Information: This work was supported by the German Centre of Lung Research (DZL). COMPERA is funded by unrestricted grants from Acceleron , Actelion Pharmaceuticals , Bayer , OMT , and GSK . These companies were not involved in data analysis or the writing of this manuscript. Publisher Copyright: © 2020 The Authors Copyright: Copyright 2020 Elsevier B.V., All rights reserved.The term idiopathic pulmonary arterial hypertension (IPAH) is used to categorize patients with pre-capillary pulmonary hypertension of unknown origin. There is considerable variability in the clinical presentation of these patients. Using data from the Comparative, Prospective Registry of Newly Initiated Therapies for Pulmonary Hypertension, we performed a cluster analysis of 841 patients with IPAH based on age, sex, diffusion capacity of the lung for carbon monoxide (DLCO; <45% vs ≥45% predicted), smoking status, and presence of comorbidities (obesity, hypertension, coronary heart disease, and diabetes mellitus). A hierarchical agglomerative clustering algorithm was performed using Ward's minimum variance method. The clusters were analyzed in terms of baseline characteristics; survival; and response to pulmonary arterial hypertension (PAH) therapy, expressed as changes from baseline to follow-up in functional class, 6-minute walking distance, cardiac biomarkers, and risk. Three clusters were identified: Cluster 1 (n = 106; 12.6%): median age 45 years, 76% females, no comorbidities, mostly never smokers, DLCO ≥45%; Cluster 2 (n = 301; 35.8%): median age 75 years, 98% females, frequent comorbidities, no smoking history, DLCO mostly ≥45%; and Cluster 3 (n = 434; 51.6%): median age 72 years, 72% males, frequent comorbidities, history of smoking, and low DLCO. Patients in Cluster 1 had a better response to PAH treatment than patients in the 2 other clusters. Survival over 5 years was 84.6% in Cluster 1, 59.2% in Cluster 2, and 42.2% in Cluster 3 (unadjusted p < 0.001 for comparison between all groups). The population of patients diagnosed with IPAH is heterogenous. This cluster analysis identified distinct phenotypes, which differed in clinical presentation, response to therapy, and survival.publishersversionPeer reviewe

Variability of Intensive Care Admission Decisions for the Very Elderly

Although increasing numbers of very elderly patients are requiring intensive care, few large sample studies have investigated ICU admission of very elderly patients. Data on pre triage by physicians from other specialities is limited. This observational cohort study aims at examining inter-hospital variability of ICU admission rates and its association with patients' outcomes. All patients over 80 years possibly qualifying for ICU admission who presented to the emergency departments (ED) of 15 hospitals in the Paris (France) area during a one-year period were prospectively included in the study. Main outcome measures were ICU eligibility, as assessed by the ED and ICU physicians; in-hospital mortality; and vital and functional status 6 months after the ED visit. 2646 patients (median age 86; interquartile range 83–91) were included in the study. 94% of participants completed follow-up (n = 2495). 12.4% (n = 329) of participants were deemed eligible for ICU admission by ED physicians and intensivists. The overall in-hospital and 6-month mortality rates were respectively 27.2% (n = 717) and 50.7% (n = 1264). At six months, 57.5% (n = 1433) of patients had died or had a functional deterioration. Rates of patients deemed eligible for ICU admission ranged from 5.6% to 38.8% across the participating centers, and this variability persisted after adjustment for patients' characteristics. Despite this variability, we found no association between level of ICU eligibility and either in-hospital death or six-month death or functional deterioration. In France, the likelihood that a very elderly person will be admitted to an ICU varies widely from one hospital to another. Influence of intensive care admission on patients' outcome remains unclear