Regulación de la adhesividad de células madre mesenquimales en biomateriales con distintas composiciones y topografías

Las células responden a estímulos tanto mecánicos como bioquímicos en el organismo. En la ingeniería de tejidos combinar ambos aspectos es esencial para conocer mejor el comportamiento celular. Se han empleado células madre adultas cultivadas en condiciones estáticas y dinámicas simuladas en un bioreactor de perfusión. Las células madre se diferencian hacia diferentes estirpes por medio de la ruta WNT dependiente de la beta‐catenina. Esta ruta está mecanoregulada, un mecanismo de regulación a su vez lo constituyen los procesos epignéticos. Se estudió además el efecto de la rugosidad de Tántalo y Niobio sobre las células madre demostrando cómo la topografía y condiciones de nicho celular influyen directamente en la maquinaria de metilación y regulación génica

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear un derstanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5–7 vast areas of the tropics remain understudied.8–11 In the American tropics, Amazonia stands out as the world’s most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepre sented in biodiversity databases.13–15 To worsen this situation, human-induced modifications16,17 may elim inate pieces of the Amazon’s biodiversity puzzle before we can use them to understand how ecological com munities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple or ganism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region’s vulnerability to environmental change. 15%–18% of the most ne glected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lostinfo:eu-repo/semantics/publishedVersio

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear understanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5,6,7 vast areas of the tropics remain understudied.8,9,10,11 In the American tropics, Amazonia stands out as the world's most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepresented in biodiversity databases.13,14,15 To worsen this situation, human-induced modifications16,17 may eliminate pieces of the Amazon's biodiversity puzzle before we can use them to understand how ecological communities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple organism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region's vulnerability to environmental change. 15%–18% of the most neglected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lost

A new biocompatible and antibacterial phosphate free glass-ceramic for medical applications

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License.In the attempt to find valid alternatives to classic antibiotics and in view of current limitations in the efficacy of antimicrobial-coated or loaded biomaterials, this work is focused on the development of a new glass-ceramic with antibacterial performance together with safe biocompatibility. This bactericidal glass-ceramic composed of combeite and nepheline crystals in a residual glassy matrix has been obtained using an antimicrobial soda-lime glass as a precursor. Its inhibitory effects on bacterial growth and biofilm formation were proved against five biofilm-producing reference strains. The biocompatibility tests by using mesenchymal stem cells derived from human bone indicate an excellent biocompatibility.This work was supported by the Spanish Ministry of Economy and Competitiveness (MINECO) under the projectMAT2012-38645, and by CSIC project ref. nu 201360E012. B. Cabal acknowledges financial support from JAE-Doc program (CSIC, cofounded by FSE).Peer Reviewe

In vitro and in vivo evaluation of a new zirconia/tantalum biocermet for medical implants

Poster presentado en el 9° Congresso Latino-Americano de Orgãos Artificiais e Biomateriais y el 13° Congresso da Sociedade Latino Americana de Biomateriais, Orgãos Artificiais e Engenharia de Tecidos, que tuvieron lugar del 24 al 27 de agosto de 2016 en Foz do Iguaçu (Brasil).After decades of research there is still a need for developing implants with suitable mechanical properties, biocompatibility, high corrosion resistance and low wear, as well as a good osseointegration. New multifunctional materials containing chemically inert nature, wear resistance and hardness ceramics (3Y-TZP) reinforced by non-toxic and non-magnetic metal (Tantalum) were fabricated by wet mixing of powders and spark plasma sintering. The microstructural architectures from nano to micro-macro levels ensure excellent composites' mechanical properties under static and cyclic loading accompanied by a tribological performance and resistance towards low-temperature degradation. In comparison with commercially available tetragonal zirconia stabilized with 3 mol% of yttria, the obtained compositions showed significant enhancement of structural properties. The aim of this study was to investigate the biological tolerance of these new zirconia/Ta biocermets implants with both in vitro and in vivo approaches. In vitro (mesenquimal cells), the biocermets showed no deleterious effect on cell proliferation, extra-cellular matrix production or on cell morphology. Cylinders of biocermets, as well as commercially Ta and zirconia rods were implanted in the tibiae of New Zealand white rabbits. All the animals were euthanatized after 6 months. The specimens were processed to obtain thin ground sections. A newly formed bone was observed in close contact with material surfaces. No inflamed or multinucleated cells were present.In vitro studies and in vivo studies revealed that 3Y-TZP/Ta biocermets appeared to be biocompatible.This opens the possibility to produce novel biomaterials with a optimal combination of properties (mechanical, tribological and biological) to make implants for a variety of different hard tissue replacement applications

In vitro and in vivo evaluation of a new zirconia/niobium biocermet for hard tissue replacement

Metals and ceramics are commonly used in orthopaedics, dentistry and other load bearing applications. However, the use of ceramic matrix composites reinforced with biocompatible metals for heavy load-bearing hard tissue replacement applications has not previously been reported. In order to improve the reliability and the mechanical properties of biomedical implants, new zirconia-Nb composites have been recently developed. The aim of this study was to investigate the biological tolerance of these new zirconia/Nb biocermets implants with both in vitro and in vivo approaches. At first, human bone marrow derived mesenchymal stem cells were cultured on sintered biocermet discs with polished surfaces and were compared with responses to niobium metal. In vitro, the biocermets showed no deleterious effect on cell proliferation, extra-cellular matrix production or on cell morphology. Furthermore, the biocermet showed a higher percentage of cell proliferation than Nb metal. On the other hand, the bone response to these new zirconia/Nb biocermets was studied. Cylinders of biocermets, as well as commercially Nb rod were implanted in the tibiae of New Zealand white rabbits. All the animals were euthanatized after 6 months. The specimens were processed to obtain thin ground sections. The slides were observed in normal transmitted light microscope. A newly formed bone was observed in close contact with material surfaces. No inflamed or multinucleated cells were present. This study concluded that zirconia/Nb composites are biocompatible and osteoconductive. The ceramic-metal composite has even better osteointegration ability than pure Nb. In conclusion, zirconia-Nb biocermet is suitable for heavy load-bearing hard tissue replacement from the point of view of both mechanical properties and biocompatibility.This work was supported by the Spanish Ministry of Science and Innovation (MICINN) under the project MAT2012-38645.Peer Reviewe