1,720,977 research outputs found
Variazioni legate all'età nelle cellule stromali mesenchimali umane derivate da midollo osseo: impatto su morfologia, profilo di espressione genica, attività immunomodulatrice ed espressione dei miRNA.
No full textLe cellule mesenchimali stromali (MSC) sono cellule multipotenti che rappresentano una componente fondamentale del microambiente del midollo osseo. Un importante funzione esercitata dalle MSC è la capacità di modulare l'intensità della risposta immunitaria attraverso la produzione e secrezione di citochine e di vescicole extracellulari (EVs). Con l'invecchiamento dell'ospite, anche le MSC subiscono dei cambiamenti legati alla senescenza, che giocano un ruolo importante nella patogenesi di numerose malattie dell'anziano, spesso associate ad una infiammazione di basso grado, cronica e sistemica definita “inflammaging”. Le MSC rappresentano un target terapeutico promettente in molti ambiti della medicina (medicina rigenerativa, malattie autoimmuni ed infiammatorie croniche, patologie oncologiche) grazie alla loro stabilità genetica, scarsa immunogenicità e significative abilità di rigenerazione ed immunodulazione.
Lo scopo principale di questo progetto è stato di identificare alterazioni molecolari e funzionali delle MSC isolate dal midollo osseo di soggetti sani, giovani ed anziani.
Differenti caratteristiche sono state studiate:
-la morfologia, il fenotipo e la capacità replicativa delle MSC;
-i marcatori di senescenza;
-l'espressione di geni implicati nella proliferazione cellulare, nel supporto ematopoietico, nell'immunomodulazione;
-l'attività delle MSC in risposta ad un ambiente infiammatorio;
-il potenziale immunomodulatorio di MSC ed EVs: effetti sulla polarizzazione dei macrofagi;
-il miRnoma delle MSC.
Le MSC isolate da donatori anziani presentano taglia e granularità maggiori e dimostrano un tempo di raddoppiamento nonché l'espressione di p16 e p21 aumentate. Abbiamo riscontrato un aumento dell'espressione di geni pro-infiammatori (TGF-beta, GAL1, IL-6, IL-8) nei soggetti anziani in risposta ad un ambiente infiammatorio. Le MSC hanno mostrato un impatto significativo sulla polarizzazione dei macrofagi verso i fenotipi M1 ed M2: in particolare, MSC isolate da donatori giovani sono associate ad una ridotta espressione di marcatori tipici del fenotipo pro-infiammatorio M1 (CCL2 e TNF-alfa) e ad un'incrementata espressione di marcatori del fenotipo anti-infiammatorio M2 (IL-10, TGM2 e CD206). Questo effetto risulta meno marcato ripetendo lo stesso test dopo induzione di uno stato di senescenza replicativa nelle MSC degli stessi donatori. Questi dati sono stati confermati sia su macrofagi derivati dalla linea cellulare THP-1 che su macrofagi derivati da monociti circolanti (MDMs) di soggetti sani.
L'analisi dell'espressione dei miRNA delle MSC ha mostrato delle differenze in diversi miRNA conosciuti per avere un ruolo significativo in alcuni processi di immunomodulazione: in particolare l'espressione di miR-193b-3p risulta notevolmente incrementata dopo co-cultura dei macrofagi con le MSC isolate da donatori giovani. Questo miRNA sembra regolare una via biologica che porta alla sottoregolazione di CCL2 attraverso la regolazione di STAT1 e quindi giocare un ruolo importante nell'attività di immunomodulazione esercitata dalle MSC.
Questi risultati suggeriscono che: 1) le MSC di soggetti di diversa età mostrano delle differenze in taglia, morfologia e capacità di proliferazione; 2) l'espressione genica delle MSC sembra variare a seconda dell'età dei donatori: nei soggetti anziani le MSC presentano una limitata capacità di immunomodulazione ed in particolare una ridotta inibizione dell'attività pro-infiammatoria dei macrofagi con fenotipo M1; 3) la polarizzazione de macrofagi sembrerebbe essere fortemente influenzata dall'attività di alcuni miRNA prodotti dalle MSC e tale produzione varia secondo l'età.Mesenchymal stromal cells (MSC) are one of the main cellular components of the bone marrow microenvironment. An important feature of MSC is their immunomodulating capacity, partially mediated by secreted cytokines and extracellular vesicles (EVs). With host aging, MSC also undergo age-related changes, which play an important role in the pathogenesis of several diseases of the elderly, often related to a persistent low-grade systemic pro-inflammatory status defined “inflammaging”. MSC present a promising therapeutic potential in several medical fields (regenerative medicine, autoimmune and chronic inflammatory disorders, neoplastic disorders) which rely on their genetic stability, poor immunogenicity, reparative and immunomodulatory abilities.
The main aim of this project was to identify molecular and functional alterations of mesenchymal stem cells (MSC) derived from young and elderly bone marrow healthy donors.
Different characteristics have been evaluated:
-MSC morphology, phenotype and expansion;
-Markers of senescence;
-Expression of genes implicated in cell proliferation, hematopoietic support, immunomodulation;
-MSC response to inflammatory priming;
-Immunomodulatory potential of MSC and EVs: effects on macrophage polarization;
-Establishment and comparison of the miRnome of MSC.
MSC derived from elderly donors are large, flat and more granular and display increased population doubling time and p16 and p21 expression. We reported an increased expression of pro-inflammatory genes (TGF-beta, GAL1, IL-6, IL-8) in older patients in response to inflammatory priming. MSC show a significant impact on macrophage polarization towards M1 and M2 status: particularly, MSC from young donors induced a reduction of typical M1 markers expression such as CCL2 and TNF-alfa, and enhance the switch to anti-inflammatory M2 status, as shown by increased levels of IL-10, TGM2, and CD206 on both THP-1 cells and monocyte-derived macrophages (MDMs). Moreover, this effect is less marked when using replicative senescent MSC from the same donors. The majority of EVs derived from MSC showed a size of 100-250 nm and were actively phagocytosed by macrophages.
The analysis of miRNA expression in EVs revealed a significant difference for miRNA known to be involved in macrophage polarization and particularly the expression of miR-193b-3p is strongly increased after co-culture of macrophages with MSC. This miRNA regulates a biological pathway leading to CCL2 down-expression through STAT1 regulation and preliminary data suggest that this might be one of the pathways explaining MSC immunomodulating activity.
These results suggest that: 1) MSC show differences in size, morphology, colony-forming ability; 2) MSC gene expression profile seems to vary according to subjects’ age and particularly in old donors seem to be characterized by an impaired immunomodulating activity, with a reduced inhibition of macrophage M1 status; 3) Macrophage polarization could be strongly influenced by EVs activity through miRNA production which seems to vary according to donors’ age
Severe Thrombotic Complications in Congenital Afibrinogenemia: A Pathophysiological and Management Dilemma
No full textCongenital afibrinogenemia (CA) is a disease characterized by a complex pathophysiology, involving both the procoagulant and fibrinolytic systems, as well as platelet activity. Although hemorrhagic diathesis represents the most frequent clinical presentation of this disorder, severe thrombotic events can occur. It is not yet clear if these events are strictly related to the disease itself or to the fibrinogen replacement therapy. Different hypotheses on the pathophysiological mechanisms have been proposed. It is well known that fibrinogen/fibrin has a role in the downregulation of thrombin generation in plasma. In the absence of circulating fibrinogen, this "antithrombin" activity is missing and plasma thrombin levels rise; this excess of thrombin could promote clotting of the infused fibrinogen, initiating the thrombotic process. Furthermore, the observation of impaired plasmin generation in the plasma of CA patients has raised the hypothesis of a fibrinolytic system deficiency. We report the case of a CA male patient who at the age of 36 years experienced an arterial thrombosis in his left lower limb. Despite an aggressive medical treatment with low-molecular-weight heparin, fibrinolytic and antiplatelet agents, the arterial thrombosis progressed to the obstruction of the whole left arterial district and the patient underwent the amputation of the left lower limb. This case demonstrates the complexity of pathophysiology and clinical management of a "so-called" bleeding disorder as CA
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Retrospective Evaluation of Phenotype and Management of A-hypo-dys-Fibrinogenemia in a Cohort of Italian Patients
No full text- …
