72 research outputs found

    Human mesenchymal stromal cells inhibit platelet activation and aggregation involving CD73-converted adenosine

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    Background: Mesenchymal stromal cells (MSCs) are promising cell therapy candidates. Clinical application is considered safe. However, minor side effects have included thromboembolism and instant blood-mediated inflammatory reactions suggesting an effect of MSC infusion on hemostasis. Previous studies focusing on plasmatic coagulation as a secondary hemostasis step detected both procoagulatory and anticoagulatory activities of MSCs. We now focus on primary hemostasis and analyzed whether MSCs can promote or inhibit platelet activation. Methods: Effects of MSCs and MSC supernatant on platelet activation and function were studied using flow cytometry and further platelet function analyses. MSCs from bone marrow (BM), lipoaspirate (LA) and cord blood (CB) were compared to human umbilical vein endothelial cells or HeLa tumor cells as inhibitory or activating cells, respectively. Results: BM-MSCs and LA-MSCs inhibited activation and aggregation of stimulated platelets independent of the agonist used. This inhibitory effect was confirmed in diagnostic point-of-care platelet function analyses in platelet-rich plasma and whole blood. Using inhibitors of the CD39–CD73–adenosine axis, we showed that adenosine produced by CD73 ectonucleotidase activity was largely responsible for the LA-MSC and BM-MSC platelet inhibitory action. With CB-MSCs, batch-dependent responses were obvious, with some batches exerting inhibition and others lacking this effect. Conclusions: Studies focusing on plasmatic coagulation suggested both procoagulatory and anticoagulatory activities of MSCs. We now show that MSCs can, dependent on their tissue origin, inhibit platelet activation involving adenosine converted from adenosine monophosphate by CD73 ectonucleotidase activity. These data may have strong implications for safety and risk/benefit assessment regarding MSCs from different tissue sources and may help to explain the tissue protective mode of action of MSCs. The adenosinergic pathway emerges as a key mechanism by which MSCs exert hemostatic and immunomodulatory functions

    Autologous Lipofilling Improves Clinical Outcome in Patients With Symptomatic Dermal Scars Through Induction of a Pro-Regenerative Immune Response

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    BACKGROUND: Autologous lipofilling is an emerging procedure to treat and possibly reverse dermal scars and to reduce scar-related pain, but its efficacy and mechanisms are poorly understood. OBJECTIVES: The aim of this study was to test the hypothesis that repeated lipografts reverse dermal scars by reinitiation of wound healing. METHODS: In a prospective, non-placebo-controlled clinical study, 27 adult patients with symptomatic scars were given 2 lipofilling treatments at 3-month intervals. As primary outcome, clinical effects were measured with the Patient and Observer Scar Assessment Scale (POSAS). Scar biopsies were taken before and after treatments to assess scar remodeling at a cellular level. RESULTS: Twenty patients completed the study. Patients’ scars improved after lipofilling. The total POSAS scores (combined patient and observer scores) decreased from 73.2  [14.7] points (mean [standard deviation]) pretreatment to 46.1 [14.0] and 32.3 [13.2] points after the first and second lipofilling treatment, respectively. Patient POSAS scores decreased from 37.3 [8.8] points to 27.2 [11.3] and 21.1 [11.4] points, whereas observer POSAS scores decreased from 35.9 [9.5] points to 18.9 [6.0] and 11.3 [4.5] points after the first and second treatment, respectively. After each lipofilling treatment, T lymphocytes, mast cells, and M2 macrophages had invaded scar tissue and were associated with increased vascularization. In addition, the scar-associated epidermis showed an increase in epidermal cell proliferation to levels similar to that normal in skin. Moreover, lipofilling treatment caused normalization of the extracellular matrix organization towards that of normal skin. CONCLUSIONS: Autologous lipofilling improves the clinical outcome of dermal scars through the induction of a pro-regenerative immune response, increased vascularization, and epidermal proliferation and remodeling of scar tissue extracellular matrix. LEVEL OF EVIDENCE: 4: [Image: see text

    Gaia GraL: Gaia DR2 Gravitational Lens Systems. VIII. A radio census of lensed systems

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    We present radio observations of 24 confirmed and candidate strongly lensed quasars identified by the Gaia Gravitational Lenses (GraL) working group. We detect radio emission from 8 systems in 5.5 and 9 GHz observations with the Australia Telescope Compact Array (ATCA), and 12 systems in 6 GHz observations with the Karl G. Jansky Very Large Array (VLA). The resolution of our ATCA observations is insufficient to resolve the radio emission into multiple lensed images, but we do detect multiple images from 11 VLA targets. We have analysed these systems using our observations in conjunction with existing optical measurements, including measuring offsets between the radio and optical positions, for each image and building updated lens models. These observations significantly expand the existing sample of lensed radio quasars, suggest that most lensed systems are detectable at radio wavelengths with targeted observations, and demonstrate the feasibility of population studies with high resolution radio imaging

    Gaia GraL: Gaia DR2 gravitational lens systems – VIII. A radio census of lensed systems

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    © 2024 The Author(s). Published by Oxford University Press on behalf of Royal Astronomical Society. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY), https://creativecommons.org/licenses/by/4.0/We present radio observations of 24 confirmed and candidate strongly lensed quasars identified by the Gaia Gravitational Lenses working group. We detect radio emission from eight systems in 5.5 and 9 GHz observations with the Australia Telescope Compact Array (ATCA), and 12 systems in 6 GHz observations with the Karl G. Jansky Very Large Array (VLA). The resolution of our ATCA observations is insufficient to resolve the radio emission into multiple lensed images, but we do detect multiple images from 11 VLA targets. We have analysed these systems using our observations in conjunction with existing optical measurements, including measuring offsets between the radio and optical positions for each image and building updated lens models. These observations significantly expand the existing sample of lensed radio quasars, suggest that most lensed systems are detectable at radio wavelengths with targeted observations, and demonstrate the feasibility of population studies with high-resolution radio imaging.Peer reviewe

    The CARMENES search for exoplanets around M dwarfs High-resolution optical and near-infrared spectroscopy of 324 survey stars

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    The CARMENES radial velocity (RV) survey is observing 324 M dwarfs to search for any orbiting planets. In this paper, we present the survey sample by publishing one CARMENES spectrum for each M dwarf. These spectra cover the wavelength range 520–1710 nm at a resolution of at least R >80 000, and we measure its RV, Hα emission, and projected rotation velocity. We present an atlas of high-resolution M-dwarf spectra and compare the spectra to atmospheric models. To quantify the RV precision that can be achieved in low-mass stars over the CARMENES wavelength range, we analyze our empirical information on the RV precision from more than 6500 observations. We compare our high-resolution M-dwarf spectra to atmospheric models where we determine the spectroscopic RV information content, Q, and signal-to-noise ratio. We find that for all M-type dwarfs, the highest RV precision can be reached in the wavelength range 700–900 nm. Observations at longer wavelengths are equally precise only at the very latest spectral types (M8 and M9). We demonstrate that in this spectroscopic range, the large amount of absorption features compensates for the intrinsic faintness of an M7 star. To reach an RV precision of 1 m s−1 in very low mass M dwarfs at longer wavelengths likely requires the use of a 10 m class telescope. For spectral types M6 and earlier, the combination of a red visual and a near-infrared spectrograph is ideal to search for low-mass planets and to distinguish between planets and stellar variability. At a 4 m class telescope, an instrument like CARMENES has the potential to push the RV precision well below the typical jitter level of 3–4 m s−1

    The CARMENES search for exoplanets around M dwarfs. Two temperate Earth-mass planet candidates around Teegarden’s Star

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    Context.Teegarden’s Star is the brightest and one of the nearest ultra-cool dwarfs in the solar neighbourhood. For its late spectral type (M7.0 V),the star shows relatively little activity and is a prime target for near-infrared radial velocity surveys such as CARMENES.Aims.As part of the CARMENES search for exoplanets around M dwarfs, we obtained more than 200 radial-velocity measurements of Teegarden’sStar and analysed them for planetary signals.Methods.We find periodic variability in the radial velocities of Teegarden’s Star. We also studied photometric measurements to rule out stellarbrightness variations mimicking planetary signals.Results.We find evidence for two planet candidates, each with 1.1M⊕minimum mass, orbiting at periods of 4.91 and 11.4 d, respectively. Noevidence for planetary transits could be found in archival and follow-up photometry. Small photometric variability is suggestive of slow rotationand old age.Conclusions.The two planets are among the lowest-mass planets discovered so far, and they are the first Earth-mass planets around an ultra-cooldwarf for which the masses have been determined using radial velocities.We thank the referee Rodrigo Díaz for a careful review andhelpful comments. M.Z. acknowledges support from the Deutsche Forschungs-gemeinschaft under DFG RE 1664/12-1 and Research Unit FOR2544 “BluePlanets around Red Stars”, project no. RE 1664/14-1. CARMENES isan instrument for the Centro Astronómico Hispano-Alemán de Calar Alto(CAHA, Almería, Spain). CARMENES is funded by the German Max-Planck-Gesellschaft (MPG), the Spanish Consejo Superior de InvestigacionesCientíficas (CSIC), the European Union through FEDER/ERF FICTS-2011-02 funds, and the members of the CARMENES Consortium (Max-Planck-Institut für Astronomie, Instituto de Astrofísica de Andalucía, LandessternwarteKönigstuhl, Institut de Ciències de l’Espai, Institut für Astrophysik Göttingen,Universidad Complutense de Madrid, Thüringer Landessternwarte Tautenburg,Instituto de Astrofísica de Canarias, Hamburger Sternwarte, Centro de Astro-biología and Centro Astronómico Hispano-Alemán), with additional contribu-tions by the Spanish Ministry of Economy, the German Science Foundationthrough the Major Research Instrumentation Programme and DFG ResearchUnit FOR2544 “Blue Planets around Red Stars”, the Klaus Tschira Stiftung, thestates of Baden-Württemberg and Niedersachsen, and by the Junta de Andalucía.Based on data from the CARMENES data archive at CAB (INTA-CSIC). Thisarticle is based on observations made with the MuSCAT2 instrument, devel-oped by ABC, at Telescopio Carlos Sánchez operated on the island of Tener-ife by the IAC in the Spanish Observatorio del Teide. Data were partly col-lected with the 150-cm and 90-cm telescopes at the Sierra Nevada Observa-tory (SNO) operated by the Instituto de Astrofísica de Andalucía (IAA-CSIC).Data were partly obtained with the MONET/South telescope of the MOnitoringNEtwork of Telescopes, funded by the Alfried Krupp von Bohlen und HalbachFoundation, Essen, and operated by the Georg-August-Universität Göttingen,the McDonald Observatory of the University of Texas at Austin, and the SouthAfrican Astronomical Observatory. We acknowledge financial support from theSpanish Agencia Estatal de Investigación of the Ministerio de Ciencia, Inno-vación y Universidades and the European FEDER/ERF funds through projectsAYA2015-69350-C3-2-P, AYA2016-79425-C3-1/2/3-P, AYA2018-84089, BES-2017-080769, BES-2017-082610, ESP2015-65712-C5-5-R, ESP2016-80435-C2-1/2-R, ESP2017-87143-R, ESP2017-87676-2-2, ESP2017-87676-C5-1/2/5-R, FPU15/01476, RYC-2012-09913, the Centre of Excellence ”Severo Ochoa”and ”María de Maeztu” awards to the Instituto de Astrofísica de Canarias (SEV-2015-0548), Instituto de Astrofísica de Andalucía (SEV-2017-0709), and Cen-tro de Astrobiología (MDM-2017-0737), the Generalitat de Catalunya throughCERCA programme”, the Deutsches Zentrum für Luft- und Raumfahrt throughgrants 50OW0204 and 50OO1501, the European Research Council through grant694513, the Italian Ministero dell’instruzione, dell’università de della ricerca andUniversità degli Studi di Roma Tor Vergata through FFABR 2017 and “Mis-sion: Sustainability 2016”, the UK Science and Technology Facilities Council through grant ST/P000592/1, the Israel Science Foundation through grant848/16, the Chilean CONICYT-FONDECYT through grant 3180405, the Mexi-can CONACYT through grant CVU 448248, the JSPS KAKENHI through grantsJP18H01265 and 18H05439, and the JST PRESTO through grant JPMJPR1775

    The CARMENES search for exoplanets around M dwarfs HD147379 b: A nearby Neptune in the temperate zone of an early-M dwarf

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    We report on the first star discovered to host a planet detected by radial velocity (RV) observations obtained within the CARMENES survey for exoplanets around M dwarfs. HD 147379 (V = 8.9 mag, M = 0.58 ± 0.08 M⊙), a bright M0.0 V star at a distance of 10.7 pc, is found to undergo periodic RV variations with a semi-amplitude of K = 5.1 ± 0.4 m s−1 and a period of P = 86.54 ± 0.06 d. The RV signal is found in our CARMENES data, which were taken between 2016 and 2017, and is supported by HIRES/Keck observations that were obtained since 2000. The RV variations are interpreted as resulting from a planet of minimum mass mP sin i = 25 ± 2 M⊕, 1.5 times the mass of Neptune, with an orbital semi-major axis a = 0.32 au and low eccentricity (e < 0.13). HD 147379 b is orbiting inside the temperate zone around the star, where water could exist in liquid form. The RV time-series and various spectroscopic indicators show additional hints of variations at an approximate period of 21.1 d (and its first harmonic), which we attribute to the rotation period of the star.FEDER/ERF FICTS-2011-02 fundsMajor Research Instrumentation Programme and DFG Research Unit FOR2544 “Blue Planets around Red StarsEuropean Research Council (ERC-279347), Deutsche Forschungsgemeinschaft (RE 1664/12-1, RE 2694/4-1), Bundesministerium für Bildung und Forschung (BMBF-05A14MG3, BMBF-05A17MG3), Spanish Ministry of Economy and Competitiveness (MINECO, grants AYA2015-68012-C2-2-P, AYA2016-79425-C3-1,2,3-P, AYA2015-69350-C3-2-P, AYA2014-54348-C03- 01, AYA2014-56359-P, AYA2014-54348-C3-2-R, AYA2016-79425-C3-3-P and 2013 Ramòn y Cajal program RYC-2013-14875), Fondo Europeo de Desarrollo Regional (FEDER, grant ESP2016-80435-C2-1-R, ESP2015-65712-C5- 5-R), Generalitat de Catalunya/CERCA programme, Spanish Ministerio de Educación, Cultura y Deporte, programa de Formación de Profesorado Universitario (grant FPU15/01476), Deutsches Zentrum für Luft- und Raumfahrt (grants 50OW0204 and 50OO1501), Office of Naval Research Global (award no. N62909-15-1-2011), Mexican CONACyT grant CB-2012-183007

    The CARMENES search for exoplanets around M dwarfs. First visual-channel radial-velocity measurements and orbital parameter updates of seven M-dwarf planetary systems

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    Stars and planetary system
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