Sangramiento posextracción dentaria y medidas para su control en pacientes tratados con antiagregantes plaquetarios / Bleeding after tooth extraction and measures for its control in patients treated with antiplatelet agents

Introducción: El desarrollo de las ciencias médicas trae consigo un incremento en la expectativa de vida, junto a la detección temprana de un gran número de enfermedades crónicas como las cerebrovasculares y cardiovasculares, que son tratadas rutinariamente con medicamentos antiagregantes plaquetarios. El conocimiento del manejo de estos pacientes ante los procedimientos quirúrgicos estomatológicos constituye un reto en la práctica diaria profesional. Objetivo: Determinar el nivel de sangramiento posextracción dentaria en pacientes con enfermedad cardiovascular y cerebrovascular, según el tipo de antiagregantes plaquetarios y grupo dentario, así como la frecuencia de utilización de las medidas para su control. Métodos: Se efectuó un estudio observacional, descriptivo, longitudinal y prospectivo con un universo de 136 pacientes de más de 20 años, remitidos por su cardiólogo y que necesitaban realizarse extracciones dentarias sin modificar su tratamiento con antiagregantes plaquetarios. Las variables estudiadas fueron la enfermedad sistémica, el tipo de antiagregante plaquetario, el nivel de sangramiento, grupo dentario intervenido y método hemostático utilizado. Resultados: La mitad de los pacientes estudiados no presentó sangramiento posextracción dentaria. En los pacientes tratados con aspirina o clopidogrel predominaron los sujetos sin sangramiento para un 84,3 por ciento y 62,5 por ciento, respectivamente. En los de doble antiagregación prevaleció el sangramiento moderado con un 46,3 por ciento. Los grupos dentarios incisivo, canino y premolar no presentaron episodios de sangramiento para un 64,1 por ciento, 51,6 por ciento y 53,3por ciento, respectivamente. El método hemostático más utilizado fue la compresión de las corticales y termoterapia fría (47,8 por ciento). Conclusiones: La mitad de los pacientes con enfermedades cardiovasculares y cerebrovasculares no presentaron sangramiento posextracción dentaria(AU)

Introduction: The development of medical sciences brings with it an increase in life expectancy, together with the early detection of a large number of chronic diseases such as cerebrovascular and cardiovascular diseases, which are routinely treated with antiplatelet aggregation drugs. Knowledge on the treatment of these patients before stomatological surgical procedures constitutes a challenge in daily professional practice. Objective: To determine the level of bleeding after tooth extraction in patients with cardiovascular and cerebrovascular disease, according to the type of antiplatelet agents and dental group, as well as the frequency of use of measures for their control. Methods: An observational, descriptive, longitudinal and prospective study was carried out with a universe of 136 patients over 20 years of age, referred by their cardiologist, who needed dental extractions without modifying their treatment with antiplatelet agents. The variables studied were systemic disease, type of antiplatelet agent, level of bleeding, dental group treated and hemostatic method used. Results: Half of the patients studied did not present bleeding after tooth extraction. In patients treated with aspirin or clopidogrel, 84.3 percent and 62.5por ciento, respectively, had no bleeding. In those with double antiplatelet therapy, modera te bleeding prevailed with 46.3 The incisor, canine and premolar tooth groups did not present bleeding episodes (64.1 percent, 51.6and 53.3 percent respectively). The most commonly used hemostatic method was cortical compression and cold thermotherapy (47.8%). Conclusions: Half of the patients with cardiovascular and cerebrovascular diseases did not present bleeding after tooth extraction(AU)

Non-classical Notch signaling by MDA-MB-231 breast cancer cell-derived small extracellular vesicles promotes malignancy in poorly invasive MCF-7 cells.

Aberrant Notch signaling is implicated in breast cancer progression, and recent studies have demonstrated links between the Notch pathway components Notch1 and Notch1 intracellular domain (N1ICD) with poor clinical outcomes. Growing evidence suggests that Notch signaling can be regulated by small extracellular vesicles (SEVs). Here, we used breast cancer cell models to examine whether SEVs are involved in functional Notch signaling. We found that Notch components are packaged into MDA-MB-231- and MCF-7-derived SEVs, although higher levels of N1ICD were detected in SEVs from the more aggressive MDA-MB-231 cell line than from poorly invasive MCF-7 cells. SEV-Notch components were functional, as SEVs cargo from MDA-MB-231 cells induced the expression of Notch target genes in MCF-7 cells and triggered a more invasive and proliferative phenotype concomitant with the acquisition of mesenchymal features. Neutralization of the N1ICD cargo in MDA-MB-231-derived SEVs significantly reduced their potential to enhance the aggressiveness of MCF-7 cells in vitro and in a xenograft model. Overall, our results indicate that a SEV-mediated non-classical pathway of Notch signal transduction in breast cancer models bypasses the need for classical ligand-receptor interactions, which may have important implications in cancer.

Extracellular Vesicles Secreted by Hypoxic AC10 Cardiomyocytes Modulate Fibroblast Cell Motility.

Extracellular vesicles (EVs) are small membrane vesicles secreted by most cell types with important roles in cell-to-cell communication. To assess their relevance in the context of heart ischemia, EVs isolated from the AC10 ventricular cardiomyocyte cell line (CM-EVs), exposed to normoxia (Nx) or hypoxia (Hx), were incubated with fibroblasts (Fb) and endothelial cells (EC). CM-EVs were studied using electron microscopy, nanoparticle tracking analysis (NTA), western blotting and proteomic analysis. Results showed that EVs had a strong preference to be internalized by EC over fibroblasts, suggesting an active exosome-based communication mechanism between CM and EC in the heart. In Matrigel tube-formation assays, Hx CM-EVs were inferior to Nx CM-EVs in angiogenesis. By contrast, in a wound-healing assay, wound closure was faster in fibroblasts treated with Hx CM-EVs than with Nx CM-EVs, supporting a pro-fibrotic effect of Hx CM-EVs. Overall, these observations were consistent with the different protein cargoes detected by proteomic analysis under Nx and Hx conditions and the biological pathways identified. The paracrine crosstalk between CM-EVs, Fb, and EC in different physiological conditions could account for the contribution of CM-EVs to cardiac remodeling after an ischemic insult.

Analysis of Exosome Transfer in Mammalian Cells by Fluorescence Recovery after Photobleaching.

During the course of evolution, prokaryote and eukaryote cells have developed elegant and to some extent analogous strategies to communicate with each other and to adapt to their surrounding environment. Eukaryotic cells communicate with each other through direct interaction via juxtracrine signaling and/or by secreting soluble factors. These secreted factors can subsequently act on the cell itself (autocrine signaling) or interact with neighboring (paracrine signaling) and distant (endocrine signaling) cells. The transmission of signals between cells and tissues has been traditionally thought to be regulated by a protein-based signaling system. Typically, proteins destined for secretion into the extracellular milieu by exocytosis contain a canonical secretion-targeting sequence ( Théry et al., 2002 ). However, proteins with a non-continuous and stimulus-dependent secretion, proteins that do not contain a canonical secretion-targeting sequence, and species that might be too labile within the extracellular environment (DNA, mRNA, peptides, metabolites, miRNA and other RNA species), can be secreted in small membranous extracellular vesicles (EVs) in a specific manner ( Hagiwara et al., 2014 ). Exosomes represent one broad class of these secreted membrane vesicles with a diameter of 30-130 nm ( Cocucci et al., 2009 ; Théry et al., 2009 ; Kowal et al., 2014 ), which are formed inside the secreting cells in endosomal compartments called multivesicular bodies. Molecules loaded into exosomes as well as the intensity of the exosome transfer between cells are important parameters for the subsequent conditioning of recipient cells. Current knowledge on secretion of exosomes and their internalization in recipient cells remains incomplete. It is known that secretion intensity of exosomes varies according to the cellular type and its physiological state ( Garcia et al., 2016 ). Moreover, the different combination of transmembrane proteins on the surface of exosomes that facilitate the adhesion to the cell-extracellular matrix vary the avidity with which a recipient cell captures exosomes ( Hoshino et al., 2015 ). Here, we have developed an in vitro system by which the transfer of exosomes between cells in co-culture can be quantified using FRAP ('Fluorescence Recovery After Photobleaching') technology. This protocol has been used to analyze the effects of exosome transfer of hypoxia inducible factor 1-α (HIF-1α) in Mesenchymal Stem Cells (MSC; HIF-MSC) to Human Umbilical Cord Vein Endothelial Cells (HUVEC) (Gonzalez-King et al., 2017).

Mesenchymal Stem Cell Migration and Proliferation Are Mediated by Hypoxia-Inducible Factor-1α Upstream of Notch and SUMO Pathways.

Mesenchymal stem cells (MSCs) are effective in treating several pathologies. We and others have demonstrated that hypoxia or hypoxia-inducible factor 1 alpha (HIF-1α) stabilization improves several MSC functions, including cell adhesion, migration, and proliferation, thereby increasing their therapeutic potential. To further explore the mechanisms induced by HIF-1α in MSCs, we studied its relationship with Notch signaling and observed that overexpression of HIF-1α in MSCs increased protein levels of the Notch ligands Jagged 1-2 and Delta-like (Dll)1, Dll3, and Dll4 and potentiated Notch signaling only when this pathway was activated. Crosstalk between HIF and Notch resulted in Notch-dependent migration and spreading of MSCs, which was abolished by γ-secretase inhibition. However, the HIF-1-induced increase in MSC proliferation was independent of Notch signaling. The ubiquitin family member, small ubiquitin-like modifier (SUMO), has important functions in many cellular processes and increased SUMO1 protein levels have been reported in hypoxia. To investigate the potential involvement of SUMOylation in HIF/Notch crosstalk, we measured general SUMOylation levels and observed increased SUMOylation in HIF-1-expressing MSCs. Moreover, proliferation and migration of MSCs were reduced in the presence of a SUMOylation inhibitor, and this effect was particularly robust in HIF-MSCs. Immunoprecipitation studies demonstrated SUMOylation of the intracellular domain of Notch1 (N1ICD) in HIF-1-expressing MSCs, which contributed to Notch pathway activation and resulted in increased levels of N1ICD nuclear translocation as assessed by subcellular fractionation. SUMOylation of N1ICD was also observed in HEK293T cells with stabilized HIF-1α expression, suggesting that this is a common mechanism in eukaryotic cells. In summary, we describe, for the first time, SUMOylation of N1ICD, which is potentiated by HIF signaling. These phenomena could be relevant for the therapeutic effects of MSCs in hypoxia or under conditions of HIF stabilization.

Hypoxia Inducible Factor-1α Potentiates Jagged 1-Mediated Angiogenesis by Mesenchymal Stem Cell-Derived Exosomes.

Insufficient vessel growth associated with ischemia remains an unresolved issue in vascular medicine. Mesenchymal stem cells (MSCs) have been shown to promote angiogenesis via a mechanism that is potentiated by hypoxia. Overexpression of hypoxia inducible factor (HIF)-1α in MSCs improves their therapeutic potential by inducing angiogenesis in transplanted tissues. Here, we studied the contribution of exosomes released by HIF-1α-overexpressing donor MSCs (HIF-MSC) to angiogenesis by endothelial cells. Exosome secretion was enhanced in HIF-MSC. Omics analysis of miRNAs and proteins incorporated into exosomes pointed to the Notch pathway as a candidate mediator of exosome communication. Interestingly, we found that Jagged1 was the sole Notch ligand packaged into MSC exosomes and was more abundant in HIF-MSC than in MSC controls. The addition of Jagged1-containing exosomes from MSC and HIF-MSC cultures to endothelial cells triggered transcriptional changes in Notch target genes and induced angiogenesis in an in vitro model of capillary-like tube formation, and both processes were stimulated by HIF-1α. Finally, subcutaneous injection of Jagged 1-containing exosomes from MSC and HIF-MSC cultures in the Matrigel plug assay induced angiogenesis in vivo, which was more robust when they were derived from HIF-MSC cultures. All Jagged1-mediated effects could be blocked by prior incubation of exosomes with an anti-Jagged 1 antibody. All together, the results indicate that exosomes derived from MSCs stably overexpressing HIF-1α have an increased angiogenic capacity in part via an increase in the packaging of Jagged1, which could have potential applications for the treatment of ischemia-related disease. Stem Cells 2017;35:1747-1759.