Platelet-derived extracellular vesicles promote tenogenic differentiation of stem cells on bioengineered living fibers

Tendon mimetic scaffolds that recreate the tendon hierarchical structure and niche have increasing potential to fully restore tendon functionality. However, most scaffolds lack biofunctionality to boost the tenogenic differentiation of stem cells. In this study, we assessed the role of platelet-derived extracellular vesicles (EVs) in stem cellsâ tenogenic commitment using a 3D bioengineered in vitro tendon model. First, we relied on fibrous scaffolds coated with collagen hydrogels encapsulating human adipose-derived stem cells (hASCs) to bioengineer our composite living fibers. We found that the hASCs in our fibers showed high elongation and cytoskeleton anisotropic organization, typical of tenocytes. Moreover, acting as biological cues, platelet-derived EVs boosted the hASCsâ tenogenic commitment, prevented phenotypic drift, enhanced the deposition of the tendon-like extracellular matrix, and induced lower collagen matrix contraction. In conclusion, our living fibers provided an in vitro system for tendon tissue engineering, allowing us to study not only the tendon microenvironment but also the influence of biochemical cues on stem cell behavior. More importantly, we showed that platelet-derived EVs are a promising biochemical tool for tissue engineering and regenerative medicine applications that are worthy of further exploration, as paracrine signaling might potentiate tendon repair and regeneration

Therapeutic effects of platelet-derived extracellular vesicles in a bioengineered tendon disease model

Tendon injuries represent over 30–50% of musculoskeletal disorders worldwide, yet the available therapies do not provide complete tendon repair/regeneration and full functionality restor-ing. Extracellular vesicles (EVs), membrane-enclosed nanoparticles, have emerged as the next breakthrough in tissue engineering and regenerative medicine to promote endogenous tissue regen-eration. Here, we developed a 3D human in vitro model mimicking the signature of pathological tendon and used it to evaluate the influence that different platelet-derived EVs might have in tendon tissue repair mechanisms. For this, different EV populations isolated from platelets, small EVs (sEVs) and medium EVs (mEVs), were added to the culture media of human tendon-derived cells (hTDCs) cultured on isotropic nanofibrous scaffolds. The platelet-derived EVs increased the expression of tenogenic markers, promoted a healthy extracellular matrix (ECM) remodeling, and the synthesis of anti-inflammatory mediators. These findings suggest that platelet EVs provided relevant biochemical cues that potentiated a recovery of hTDCs phenotype from a diseased to a healthy state. Thus, this study opens new perspectives for the translation of platelet-derived EVs as therapeutics.This research was funded by the ERC CoG MagTendon grant agreement 772817; EC Twinning project Achilles 810850; Fundacao para a Ciencia e a Tecnologia (FCT) for PhD grant PD/59/2013 and PD/BD/135255/2017, individual contracts CEECIND/01375/2017 (M.G.-F.) and 2020.03410.CEECIND (R.M.A.D), and project PTDC/NAN-MAT/30595/2017

Writing 3D In vitro models of human tendon within a biomimetic fibrillar support platform

Tendinopathies are poorly understood diseases for which treatment remains challenging. Relevant in vitro models to study human tendon physiology and pathophysiology are therefore highly needed. Here we propose the automated 3D writing of tendon microphysiological systems (MPSs) embedded in a biomimetic fibrillar support platform based on cellulose nanocrystals (CNCs) self-assembly. Tendon decellularized extracellular matrix (dECM) was used to formulate bioinks that closely recapitulate the biochemical signature of tendon niche. A monoculture system recreating the cellular patterns and phenotype of the tendon core was first developed and characterized. This system was then incorporated with a vascular compartment to study the crosstalk between the two cell populations. The combined biophysical and biochemical cues of the printed pattern and dECM hydrogel were revealed to be effective in inducing human-adipose-derived stem cells (hASCs) differentiation toward the tenogenic lineage. In the multicellular system, chemotactic effects promoted endothelial cells migration toward the direction of the tendon core compartment, while the established cellular crosstalk boosted hASCs tenogenesis, emulating the tendon development stages. Overall, the proposed concept is a promising strategy for the automated fabrication of humanized organotypic tendon-on-chip models that will be a valuable new tool for the study of tendon physiology and pathogenesis mechanisms and for testing new tendinopathy treatments.The authors thank Hospital da Prelada (Porto, Portugal) for providing adipose tissue samples. The authors acknowledge the financial support from Project NORTE-01-0145-FEDER 000021 supported by Norte Portugal Regional Operational Program (NORTE 2020), under the PORTUGAL 2020 Partnership Agreement, through the European Regional Development Fund (ERDF), the European Union Framework Program for Research and Innovation HORIZON 2020, under the Twinning Grant Agreement 810850-Achilles, and European Research Council Grant Agreement 772817 and 101069302, Fundação para a Ciência e a Tecnologia for the Ph.D. grant PD/BD/129403/2017 (to S.M.B.) financed through the doctoral program in Tissue Engineering, Regenerative Medicine and Stem Cells (TERM&SC), for Contract 2020.03410.CEECIND and 2022.05526.PTDC (to R.M.A.D.). The authors acknowledge Doctor Alberto Pardo for performing the rheology measurements of the PL bioink. The schematics in Figures 1, 2A, 4A, and 6A and Table of Contents graphic were created with BioRender.com

Guiding stem cell tenogenesis by modulation of growth factor signaling and cell-scale biophysical cues in bioengineered constructs

Tendon injuries and tendinopathies are increasingly prevalent health problems currently lacking effective treatments. Tissue engineering offers promising strategies to boost the low innate regenerative ability of tendons. Within this context, the simultaneous leveraging of both physical and biochemical cues by engineered scaffolding systems can be explored to promote a stronger tenogenic response from stem cells. Here, molecularly imprinted polymeric nanoparticles (MINPs) against transforming growth factor (TGF)-β3 are combined with bioinspired anisotropic hydrogels to produce tenogenesis-inductive constructs. MINPs are first solid phase-imprinted against a TGF-β3 epitope, achieving an affinity comparable to monoclonal antibodies. MINPs and magnetically-responsive microfibers are then encapsulated together with adipose-derived stem cells within gelatin-based hydrogels, applying a magnetostatic field during gelation to align the microfibers. The created anisotropic microstructure guides cell growth and elongation unidirectionally, while MINPs act as artificial receptors for TGF-β3, potentiating its paracrine action in the cellular microenvironment. The combination of both stimuli proves effective at increasing TGF-β signaling, which promotes the expression of tendon-associated genes and corresponding protein synthesis, suggesting that microstructural cues and biomolecule sequestration act in tandem to direct cell fate commitment. Overall, this system recapitulates several elements of tendon development, constituting a promising strategy for the regeneration of this tissue

Teoría sociológica contemporánea : un debate inconcluso

1 archivo PDF (155 páginas)"Uno de los propósitos de este conjunto de ensayos es plantear, a los futuros sociólogos y a los interesados en el tema, que la sociología no es una disciplina homogénea lidereada por una corriente teórica dominante. Es una disciplina que se mantiene en un equilibrio imperfecto, donde coexisten autores que comparten el intento de crear una teoría sintetizadora y; autores que parecen estar fuera de la "corriente teórica principal", que muestran la diversidad interpretativa y de objetos de investigación que se incluyen en el quehacer sociológico. Así, aparece frente a nosotros, una disciplina heterogénea y polémica, aunque no por eso, perdida en la diversidad inagotable.

Impact of regulated and emerging pollutants and microplastics in marine ecosystems (IMPACTA project)

Marine ecosystems are nowadays subjected to a massive input of synthetic chemicals from everywhere. Unfortunately only a small portion of them is being monitored, and it is necessary to identify which pollutants can produce adverse impacts in the marine environment. IMPACTA project (CTM2013-48194-C3) is characterizing the distribution of regulated and emerging contaminants and microplastics in marine sediments, and evaluating the biological effects that they can cause (sing sublethal embryotoxicity tests, endocrine disruption and biomarkers). Sensitive and selective analytical methods are being developed and validated for pharmaceuticals, perfluorinated compounds, organophosphorus pesticides, triazines, personal care products, nonylphenols and alkylated PAHs in sediments. Thus, relevant pollutants present in coastal and offshore areas will be identified. Furthermore potential toxic effects of the contaminants present in coastal sediments are being assessed through embryotoxicity bioassays and also the biological effects on different marine species as a consequence of their exposition to specific compounds. Another relevant contribution of this project will be the assessment of the impact of micro-plastics, first time in the Spanish coastal areas. Their potential toxic effects and their role in the transference of pollutants in the marine environment are being assessed. The concentration and composition of microplastics in sediments and demersal fish stomachs are being characterized, and their potential biological effects on marine invertebrates are also being investigated

Conocimiento sobre nevos melanocíticos en los artistas del tatuaje

INTRODUCCCION: Los tatuajes pueden cubrir una lesión cutánea dificultando su reconocimiento. Por ello, resulta relevante conocer las conductas de los tatuadores de nuestra población frente a los nevos melanocíticos. OBJETIVOS: Principal: determinar si los artistas tatuadores de la ciudad de Córdoba, Argentina, poseen conocimiento sobre las características clínicas de lesiones melanocíticas sospechosas de malignidad. Secundarios: conocer las características demográficas de los tatuadores, así como su conducta frente a la piel de sus clientes.  MATERIALES Y MÉTODOS: Estudio observacional, transversal y descriptivo mediante encuestas. Se incluyeron tatuadores mayores de 18 años de la ciudad de Córdoba. Se analizaron variables sociodemográficas y laborales. Se realizó estadística descriptiva mediante porcentajes para las variables cualitativas, y las medidas estadísticas media y desviación estándar para las variables cuantitativas. RESULTADOS: Se completaron 31 encuestas entre enero del 2022 a enero del 2023. La mayoría fueron varones (n=22 71%) con una edad media de 32,7 años y secundario completo, (n=17, 54,8%) que trabajan desde hace menos de 5 años como tatuador (n=13, 41,9%). Dieciocho (58,1%) indicaron tener conocimiento sobre nevos, pero 93,5% negaron conocer el ABCDE. Al evaluar imágenes de lesiones melanocíticas, 13 tatuadores obtuvieron un puntaje > 60% de respuestas correctas, lo que representa el 41,9% del total de la muestra. Treinta (96,8%) encuestados evitan tatuar sobre nevos. El 100% de la muestra respondió que le gustaría aprender a detectar cáncer de piel.  CONCLUSIÓN: La mayoría de los encuestados desconoce el método ABCDE y falló al identificar lesiones de piel sospechosas de malignidad. Consideramos que los tatuadores podrían ser importantes aliados en la prevención del cáncer de piel

Liver injury in non-alcoholic fatty liver disease is associated with urea cycle enzyme dysregulation

The main aim was to evaluate changes in urea cycle enzymes in NAFLD patients and in two preclinical animal models mimicking this entity. Seventeen liver specimens from NAFLD patients were included for immunohistochemistry and gene expression analyses. Three-hundred-and-eighty-two biopsy-proven NAFLD patients were genotyped for rs1047891, a functional variant located in carbamoyl phosphate synthetase-1 (CPS1) gene. Two preclinical models were employed to analyse CPS1 by immunohistochemistry, a choline deficient high-fat diet model (CDA-HFD) and a high fat diet LDLr knockout model (LDLr −/−). A significant downregulation in mRNA was observed in CPS1 and ornithine transcarbamylase (OTC1) in simple steatosis and NASH-fibrosis patients versus controls. Further, age, obesity (BMI > 30 kg/m2), diabetes mellitus and ALT werefound to be risk factors whereas A-allele from CPS1 was a protective factor from liver fibrosis. CPS1 hepatic expression was diminished in parallel with the increase of fibrosis, and its levels reverted up to normality after changing diet in CDA-HFD mice. In conclusion, liver fibrosis and steatosis were associated with a reduction in both gene and protein expression patterns of mitochondrial urea cycle enzymes. A-allele from a variant on CPS1 may protect from fibrosis development. CPS1 expression is restored in a preclinical model when the main trigger of the liver damage disappears