28,121 research outputs found

    Impressão 3D de implantes customizados para regeneração óssea

    No full text
    3D printing has presented itself as potential game changer in the field of biomedical engineering. Robocasting in particular has shown excellent capability to produce custom-sized porous scaffolds using ceramic pastes. The development of materials and respective processing methods still hasn‚Äôt reached one material capable of providing both the biological and mechanical properties required for successful and comprehensive bone tissue regeneration. This work reports the fabrication, processing and characterization of a bioglass with applications as a robocasting ink for tissue regeneration. Milling procedures were adjusted resulting in a two-fold increase in milling efficiency; the effect of temperature on the surface area of mesoporous powders was also studied in detail; robocasting inks containing 35 solids loadings of both bioglass and zirconia powders were prepared and characterized rheologically; a script capable of preparing customizable CAD scaffold geometries was developed; the printing process was adjusted to increase the technique‚Äôs resolution; mechanical and biological characterization was performed using compression tests and SBF immersion coupled with MTT assays. The results show the development of the biomaterial was a success with demonstrated potential for 3D printing and biological applications. However, the mechanical properties of these bioactive scaffolds aren‚Äôt adequate for load-bearing applications.O fabrico aditivo tem mostrado um potencial enorme como agente disruptor no campo da engenharia biom√©dica. O robocasting em particular demonstra excelentes resultados na produ√ß√£o de scaffolds com geometria e tamanho de poros personaliz√°veis usando pastas cer√Ęmicas. Contudo, o desenvolvimento de materiais e t√©cnicas de processamento ainda n√£o nos presenteou com um material capaz de reunir tanto as propriedades biol√≥gicas como as mec√Ęnicas para se apresentar como um substituto √≥sseo fi√°vel em aplica√ß√Ķes biom√©dicas. Este trabalho reporta o fabrico, processamento e caracteriza√ß√£o de um biovidro para aplica√ß√Ķes em medicina regenerativa. O processo de moagem foi ajustado resultando numa efici√™ncia de moagem duas vezes superior √† encontrada na literatura; o efeito da temperatura na √°rea superficial de p√≥s mesoporosos foi estudado; pastas para robocasting contendo 35 % cargas de s√≥lidos de biovidro e zirc√≥nia foram produzidas e caracterizadas reologicamente; um script foi desenvolvido, capaz de criar modelos CAD de scaffolds com dimens√Ķes personaliz√°veis; o processo de impress√£o foi ajustado de modo a aumentar a resolu√ß√£o da t√©cnica; caracteriza√ß√Ķes mec√Ęnica e biol√≥gica foram realizadas com recurso a ensaios de compress√£o e √† imers√£o de amostras em SBF em conjunto com ensaios MTT. Os resultados apontam para o desenvolvimento com um sucesso de um biovidro com potencial para impress√£o por robocasting bem como em aplica√ß√Ķes de engenharia de tecidos. Contudo, as propriedades mec√Ęnicas das pe√ßas produzidas s√£o insuficientes para uso em situa√ß√Ķes em que se o material se possa encontrar sujeito a cargas elevadas.Mestrado em Materiais e Dispositivos Biom√©dico

    O secretoma das células estaminais mesenquimais induz a formação de sinapses em neurónios do sistema nervoso central

    No full text
    Mesenchymal stem cells (MSCs) have been the target of extensive research due to their neuroprotection and neurotrophic effects, immunomodulatory action, differentiation potential and low tumorigenicity making them an attractive source for cell-based therapies. In addition to their ability to differentiate into neural progenitors, recent studies have shown that they exert a paracrine effect in the microenvironment and surrounding cells that is responsible for its beneficial effects. The array of growth factors, cytokines, chemokines, cell adhesion molecules, hormones, exosomes, microvesicles, lipid mediators and free nucleic acids secreted by the MSCs to the culture medium is considered the secretome. Interestingly, different secretomes originated from different cell niches have shown to exhibit a neuroprotective and pro-regenerative action in several neurological disorders, including the spinal cord injury. Despite mild improvements in functional recovery obtained in MSCs clinical trials, the mechanisms responsible for its regenerative action remain elusive. Recent studies have shown that the MSCs‚Äô secretome induces neurite outgrowth and promotes cell survival. However, its effect on synapse formation is currently unknown. To address this gap, we evaluated the effect of the secretome originated from two MSC populations, the human umbilical cord perivascular cells (HUCPVC) and bone marrow-mesenchymal stem cells (BM-MSCs) on presynaptic differentiation of central nervous system neurons. We verified that the secretome of these two populations of MSC induce synaptic vesicle clustering in cortical neurons. Also, we observed a similar effect in hippocampal neurons. Furthermore, we performed a preliminary analysis of the effect of MSC secretome on mitochondria dynamics and biogenesis, an organelle imperative in all stages of neuronal development as well as in axonal regeneration. Taken together, our results show that the secretomes originated from HUCPVCs and BM-MSCs are inducers of synapse formation in neurons of the central nervous system. These results also suggest a possible role in the regulation of mitochondria biogenesis and dynamics, creating a steppingstone for future studies addressing the mechanisms that underlie these processes. These properties render the secretome of MSCs a strong candidate for future research in regenerative medicine.As c√©lulas estaminais mesenquimais (em ingl√™s, MSCs, ‚Äúmesenchymal stem cells‚ÄĚ) t√™m sido o alvo de extensa investiga√ß√£o devido ao seu efeito protetor, tr√≥fico em popula√ß√Ķes neuronais, capacidade de regular o sistema imune, potencial de diferencia√ß√£o e baixa tumorigenicidade, tornando-as uma fonte atrativa para terapias celulares. Para al√©m da sua capacidade de diferencia√ß√£o em progenitores neurais, estudos recentes t√™m demonstrado que elas exercem um efeito par√°crino no microambiente e nas c√©lulas que as rodeiam, que √© respons√°vel pelos seus efeitos ben√©ficos. O conjunto de fatores de crescimento, citocinas, quimiocinas, mol√©culas de ades√£o celular, hormonas, exosomas, microves√≠culas, mediadores lip√≠dicos e √°cidos nucleicos livres que s√£o excretados pelas MSCs para o meio de cultura, √© considerado o secretoma. Curiosamente, diferentes secretomas origin√°rios de nichos celulares diferentes t√™m demonstrado que s√£o capazes de exercer uma a√ß√£o protetora e regenerativa nos neur√≥nios em diferentes condi√ß√Ķes do sistema nervoso, incluindo na les√£o da medula espinal. Apesar dos ligeiros melhoramentos na recupera√ß√£o funcional obtidos em ensaios cl√≠nicos com MSCs, os mecanismos respons√°veis por esta a√ß√£o regenerativa permanecem desconhecidos. Estudos recentes t√™m demonstrado que o secretoma das MSCs induz um crescimento das neurites e promove a sobreviv√™ncia celular. Contudo, o seu efeito na forma√ß√£o de sinapses n√£o √© conhecido. Para preencher esta lacuna no conhecimento, neste trabalho foi avaliado o efeito do secretoma, obtido a partir de duas popula√ß√Ķes de c√©lulas estaminais mesenquimais, as c√©lulas perivasculares do cord√£o umbilical (em ingl√™s, human umbilical cord perivascular cells, HUCPVCs) e as c√©lulas estaminais mesenquimais da medula √≥ssea (em ingl√™s, bone marrow-mesenchymal stem cells, BM-MSCs), na diferencia√ß√£o pr√©-sin√°ptica em neur√≥nios do sistema nervoso central. Verificamos que o secretoma destas duas popula√ß√Ķes de MSCs induz a aglomera√ß√£o de ves√≠culas sin√°pticas em neur√≥nios corticais. Para al√©m disso, observamos um efeito semelhante em neur√≥nios hipocampais. Realiz√°mos tamb√©m uma an√°lise preliminar do efeito do secretoma das MSCs na din√Ęmica e biog√©nese da mitoc√īndria, um organelo crucial em todas as fases do desenvolvimento neuronal assim como na regenera√ß√£o axonal. Em conjunto, os resultados demonstram que o secretoma obtidos a partir das HUCPVCs e BM-MSCs, s√£o promotores da forma√ß√£o de sinapses em neur√≥nios do sistema nervoso central. Estes resultados sugerem ainda um poss√≠vel papel do secretoma na regula√ß√£o da biog√©nese e din√Ęmica mitocondrial, criando uma base para estudos futuros que abordem os mecanismos respons√°veis por estes processos. Estas propriedades tornam o secretomas das MSCs um poss√≠vel candidato para futura investiga√ß√£o na √°rea da medicina regenerativa.Mestrado em Biomedicina Molecula

    Biofuncionalização da superfície de membranas fibrosas de policaprolactona para terapias avançadas de tecido esquelético e neural

    No full text
    Tese de Doutoramento em Engenharia de Tecidos, Medicina Regenerativa e C√©lulas EstaminaisDamage of the skeletal and neural tissues has a significant impact over the quality-of-life of patients and high socio-economical costs. Current treatment options are not effective in long term, due to the suboptimal integration with the host tissue and limited bioactivity of implantable biomaterials. The immobilization of biomolecules at the surface of biomedical devices has attracted increasing interest, allowing for their local bioavailability avoiding systemic side effects and longer half-life. Envisioning the development of advanced therapies, the electrospun nanofibrous meshes (NFMs) were used as a substrate due to their fibrous structure mimic the extracellular matrix (ECM) of many tissues, allowing cell-cell and cell-biomaterial interactions. For that, the surface of polycaprolactone NFMs was activated and functionalized with amine groups allow for covalent immobilization of defined antibodies, with the capacity to selectively bind autologous biomolecules. Different biofunctional substrates with chondrogenic inductive properties were developed through the surface biofunctionalization of NFM with endogenous human fibronectin, extracellular vesicles or the combination of endogenous Transforming Growth Factor-133 and Insulin-like Growth Factor-I. All these biofunctional substrates successfully induced the chondrogenic differentiation of human bone marrow-derived mesenchymal stem cells (hBM-MSCs) under basal culture conditions. Blood-derived Nerve Growth Factor bound to the surface of NFMs remains bioactive, being an effective inducer of the neurogenic differentiation of a relevant cell line. Additionally, we developed a biofunctional system able to mimic the vasculature of bone tissue, comprising Bone Morphogenetic Protein 2 and Vascular Endothelial Growth Factor in a parallel pattern design. This biofunctional system enabled a spatially defined osteogenic and angiogenic differentiation of hBM-MSCs. The surface biofunctionalization of biomaterial substrates enables developing biofunctional systems envisioning patient-specific devices promoting skeletal and neural tissue regeneration that can maximize and extend the local efficacy and minimize the side effects of the use of biologic based therapies in patients.A deteriora√ß√£o dos tecidos esquel√©tico a neural t√™m um impacto significativo na qualidade de vida dos pacientes e um elevado custo socioecon√≥mico. Os tratamentos atualmente dispon√≠veis n√£o s√£o eficazes a longo termo, devido √† inadequada integra√ß√£o com o tecido hospedeiro e √† baixa bioatividade dos biomateriais implantados. A imobiliza√ß√£o de biomol√©culas constitui uma estrat√©gia alternativa, permitindo a biodisponibilidade local das biomol√©culas evitando efeitos colaterais sist√™micos. Ambicionando desenvolver terapias avan√ßadas, malhas fibrosas produzidas por "electrospinning" (NFMs) foram usadas como substratos polim√©ricos devido √† sua estrutura fibrosa similar a matriz extracelular (ECM) de muitos tecidos, promovendo as intera√ß√Ķes c√©lula-c√©lula e c√©lula-biomaterial. Para isso, NFMs de policaprolactona foram ativadas e funcionalizadas com grupos amina, permitindo a imobiliza√ß√£o covalente de anticorpos pr√©-definidos, com capacidade de ligar seletivamente biomol√©culas aut√≥logas. Foram desenvolvidos diferentes substratos biofuncionais, com propriedades indutoras de diferencia√ß√£o condrog√©nica, mediante liga√ß√£o de fibronectina humana, ves√≠culas extracelulares ou a combina√ß√£o do fator de transforma√ß√£o do crescimento beta 3 com o fator de crescimento semelhante √† insulina tipo I. Todos estes substratos biofuncionalizados foram capazes de induzir a diferencia√ß√£o condrog√©nica de c√©lulas estaminais mesenquimais derivadas de medula √≥ssea humana (hBM-MSCs) sendo cultivadas em condi√ß√Ķes basais. O fator de crescimento nervoso ligado √† superf√≠cie das NFMs permanece bioativo, sendo um indutor eficaz da diferencia√ß√£o neurog√©nica de uma linha celular relevante. Numa outra abordagem, foi desenvolvido um sistema biofuncional capaz de mimetizar a vasculatura de um tecido √≥sseo, ligando paralelamente a prote√≠na morfogen√©tica √≥ssea 2 e o fator de crescimento do endot√©lio vascular sobre uma mesma NFM. Este sistema biofuncional permitiu a diferencia√ß√£o osteog√©nica e angiog√©nica de hBM-MSCs espacialmente definida. Concluindo, a bioftmcionaliza√ß√£o de substratos produzidos por "electrospinning" permite o desenvolvimento de dispositivos biom√©dicos personalizados, capazes de promover a regenera√ß√£o do tecido esquel√©tico e neural, maximizando a efic√°cia local e minimizando os efeitos colaterais do uso de terapias biol√≥gicas em pacientes.To the financial support of the Portuguese Fotmdatron for Science and Technology to maize possible this PhD by awarded me with a PhD scholarship (PD/BD/113797/2015) under the Doctoral Program on Advanced Therapies for Health (FSE/POCK/PD/169/2013). The experimental work was funded by the projects SPARTAN (PTDC/CTM-BIO/4388/2014) and FRONthera (NORTE-01-0145-FEDER-0000232)

    Hydrothermal processing of 3D-printed calcium phosphate scaffolds enhances bone formation in vivo: a comparison with biomimetic treatment

    No full text
    Hydrothermal (H) processes accelerate the hydrolysis reaction of őĪ-TCP compared tothe long-establishe dbiomimetic (B) treatments. They are of special interest for patient-specific 3D-printed bone graft substitutes, where the manufacturing time represents a critical constraint. Altering the reaction conditions hasimplications forthe physicochemical propertiesof the reaction product. However, the impact of the changes produced by the hydrothermal reaction on the invivo performancewas hitherto unknown.The present study compares the bone regeneration potential of 3D printed őĪ-TCP scaffolds hardened using these two treatments in rabbit condyle monocortical defects. Although both consolidation processes resulted in biocompatible scaffolds with osseointegrative and osteoconductive properties, the amount of newly formed bone increased by one third in the hydrothermal vs the biomimetic samples. B and H scaffolds consisted mostly of high specific surface area calcium deficient hydroxyapatite (38 and 27 m2/g respectively), with H samples containing also 10 wt. %ő≤-TCP. The shrinkage produced during the consolidation process was shown to be very small in both cases, below 3%, and smaller for H than for B samples. The differences in the in vivo performance were mainly attributed to the distinct crystallisation nanostructures, which proved to have a major impact on permeability and protein adsorption capacity, using BSA as a model protein, with B samples being highly impermeable. Given the crucial role that soluble proteins play in osteogenesis, this is proposed to be a relevant factor behind the distinct in vivo performances observed for the two materials

    Molecular therapies for bone regeneration: the role of non-coding RNAs in mesenchymal stem/stromal cells

    No full text
    Mestrado em Integrado em Engenharia Biol√≥gica, Ramo de Tecnologia Qu√≠mica e AlimentarOsteoporosis is a chronic skeletal disorder characterized by loss of bone mass and deterioration of the bone tissue, which leads to an increased risk of fractures. The aetiology of this disease resides on the impairment between bone resorption (conducted by osteoclasts) and formation (conducted by osteoblasts). Considering an ageing population, it is expected a steady rising number of cases over the next years, turning osteoporosis into a serious public health issue that represents a leading cause of morbidity and mortality, mainly due to the fragility fractures. Nowadays, the osteoporosis treatments consist predominantly in anti-resorptive drugs that inhibit/prevent bone resorption but are often associated with several side effects. Therefore, the need for new approaches to promote bone homeostasis and regeneration/repair of fragility fractures in patients with osteoporosis is increasing. Over the past years microRNAs (miRNAs), a class of small non-coding RNAs that coordinate virtually all cellular mechanisms through regulation of gene expression, have gained status as important post-transcriptional regulators. Recent studies revealed their pivotal role in the pathogenesis of several human diseases, including osteoporosis. In this context and following the previous results of a microRNA microarray, the main aim of this study was to investigate the role of miR-99a-5p in osteogenic differentiation and evaluate its expression during osteoclastogenesis, crucial processes required for bone formation and repair. Also, we aimed to determine its expression in fracture healing/repair process and fragility fracture samples. To achieve our aims, we first assessed miR-99a-5p expression profile during osteogenic differentiation in both MC3T3 cell line and primary human Mesenchymal Stem/Stromal Cells by reverse transcription ‚Äď real-time quantitative polymerase chain reaction (RT-qPCR). Next, to analyze the biological effect of miR-99a-5p in osteogenesis and proliferation, we performed in vitro transfections of miR-99a-5p mimics and inhibitors. In an attempt to identify relevant mechanisms and pathways of action of miR-99a-5p we further analyzed the protein expression profile of anti-miR-99a-5p transfected cells compared to control. Furthermore, the expression profile of miR-99a-5p during osteoclastogenesis of RAW 264.7 cell line and human monocytes was investigated, as well as the effect of conditioned media from MC3T3 transfected cells on osteoclastogenesis. Finally, miR-99a-5p expression during the bone repair/regeneration process and in patients that suffered an osteoporotic fracture was determined. The results showed that miR-99a-5p was significantly down-regulated during MC3T3 osteogenic differentiation and during early stages of human primary MSC osteogenic differentiation. miR-99a-5p overexpression in pre-osteoblastic cell line MC3T3 led to a decrease of osteogenic differentiation markers, whereas its inhibition enhanced osteogenesis markers, including alkaline phosphatase expression and staining. However, modulation of miR-99a-5p levels in MC3T3 cells did not show to affect proliferation. Proteomic analysis on anti-miR-99a-5p transfected cells showed that numerous proteins known to be involved in osteogenic differentiation were altered, in comparison with the control, such as plexin-A2 (PLXA2), all-trans retinoic acid-induced differentiation factor (ARAID), ARF GTPase-activating protein GIT (GIT1) and Ephrin type-A receptor 2 (EPHA2). Furthermore, inhibition of miR-99a-5p levels were predicted to impact several pathways associated with osteoporosis, including Ephrin receptor, Pl3K-Akt and canonical Wnt pathways. In contrast to osteogenesis, miR-99a-5p was upregulated during osteoclastogenesis from both RAW 264.7 cells and primary human monocytes. We also demonstrated that inhibition of miR-99a-5p in MC3T3 increased the OPG / RANKL mRNA expression ratio and that the supernatant collected from these cells inhibited RAW 264.7 differentiation into osteoclasts. Additionally, results show that miR-99a-5p was differently expressed in a time-dependent manner in the bone marrow of rats upon a bone critical defect injury. Finally, results from bone osteoporotic human samples showed increased miR-99a-5p expression levels compared with osteoarthritis samples. Taken together, our data shows that miR-99a-5p is a critical regulator of osteogenic differentiation and suggest that modulation miR-99a-5p levels might be a strategy to re-establish bone homeostasis in fragile bones.Osteoporose √© uma doen√ßa cr√≥nica do esqueleto caracterizada pela perda de massa √≥ssea e deteriora√ß√£o do tecido √≥sseo, que conduz a um aumento do risco da ocorr√™ncia de fraturas. A etiologia desta doen√ßa reside na desregula√ß√£o entre a reabsor√ß√£o (realizada pelos osteoclastos) e a forma√ß√£o (realizada pelos osteoblastos) √≥ssea. Considerando o envelhecimento da popula√ß√£o, espera-se um aumento do n√ļmero de casos nos pr√≥ximos anos, o que torna a osteoporose um grave problema de sa√ļde p√ļblica e uma das principais causas de morbidade e mortalidade, principalmente devido √†s fraturas de fragilidade √†s quais est√£o frequentemente associadas. Atualmente, os tratamentos para a osteoporose consistem predominantemente em drogas que inibem / previnem a reabsor√ß√£o √≥ssea, mas podem ter v√°rios efeitos secund√°rios associados. Portanto, a necessidade de novas abordagens que promovam a homeostasia do osso e a regenera√ß√£o de fraturas em pacientes diagnosticados com osteoporose est√° a aumentar. Nos √ļltimos anos, os microRNAs (miRNAs), uma classe de pequenos RNAs que n√£o codificam prote√≠na e que s√£o importantes reguladores da express√£o g√©nica, est√£o a ganhar cada vez mais relev√Ęncia como reguladores de mecanismos celulares. Estudos recentes t√™m vindo a revelar o seu papel na patog√©nese de v√°rias doen√ßas, entre as quais a osteoporose. Neste contexto, o principal objetivo deste estudo foi investigar o papel do miR-99a-5p na diferencia√ß√£o osteog√©nica, um processo necess√°rio e indispens√°vel para a forma√ß√£o e regenera√ß√£o √≥ssea. Al√©m disso, explorou-se o perfil de express√£o deste microRNA na osteoclastog√©nese, durante a regenera√ß√£o de fraturas √≥sseas e em pacientes com osteoporose. Para atingir estes objetivos, come√ßamos por avaliar o perfil de express√£o do miR-99a-5p durante a diferencia√ß√£o osteog√©nica, tanto na linhagem celular MC3T3, como em c√©lulas mesenquimais do estroma humanas (MSC), por transcri√ß√£o reversa - rea√ß√£o em cadeia da polimerase quantitativa em tempo real (RT-qPCR). Em seguida, para analisar o efeito biol√≥gico do miR-99a-5p na osteog√©nese e na prolifera√ß√£o, foram realizadas transfe√ß√Ķes in vitro de oligonucle√≥tidos que mimetizam ou inibem o efeito do miR-99a-5p. Com intuito de identificar quais os alvos e vias moleculares afetadas e controladas pelo miR-99a-5p, investig√°mos o perfil de prote√≠nas expressas pelas c√©lulas transfetadas com anti-miR-99a-5p em compara√ß√£o com o controlo. Para al√©m disso, o perfil de express√£o do miR-99a-5p foi tamb√©m estudado durante a osteoclastog√©nese da linha celular RAW 264.7 e de mon√≥citos humanos, bem como o efeito do meio condicionado das c√©lulas MC3T3 transfetadas na osteoclastog√©nese. Por fim, determinou-se a express√£o do miR-99a-5p durante o processo de regenera√ß√£o √≥ssea num modelo animal e em pacientes que sofreram fraturas de fragilidade/osteopor√≥ticas. Os resultados obtidos demostraram que o miR-99a-5p √© significativamente subexpresso durante a diferencia√ß√£o osteog√©nica das MC3T3 e durante as fases iniciais da diferencia√ß√£o osteog√©nica das MSCs humanas. A sobreexpress√£o do miR-99a-5p na linha celular pr√©-osteobl√°stica MC3T3 resultou numa diminui√ß√£o dos marcadores de diferencia√ß√£o osteog√©nica enquanto que a sua inibi√ß√£o aumentou a express√£o dos mesmos marcadores osteog√©nicos, entre os quais da fosfatase alcalina. Verificou-se ainda que a modula√ß√£o dos n√≠veis do miR-99a-5p na linhagem celular MC3T3 n√£o afetou a prolifera√ß√£o celular. A an√°lise prote√≥mica dos lisados celulares provenientes das MC3T3 em que a express√£o do miR-99a-5p foi inibida, comparativamente ao controlo, mostrou que diversas prote√≠nas, conhecidas por estarem envolvidas na diferencia√ß√£o osteog√©nica, se encontravam alteradas, como a plexin-A2 (PLXA2), all-trans retinoic acid-induced differentiation factor (ARAID), ARF GTPase-activating protein GIT (GIT1) and Ephrin type-A receptor 2 (EPHA2). Os resultados mostraram tamb√©m que a inibi√ß√£o dos n√≠veis do miR-99a-5p influenciam v√°rias vias descritas como estando associadas √† osteoporose, incluindo a Ephrin receptor, Pl3K-Akt e canonical Wnt. Em contraste com o perfil de express√£o verificado durante a osteog√©nese, o miR-99a-5p encontra-se sobreexpresso ao longo da osteoclastog√©nese das RAW 264.7 e dos mon√≥citos humanos. Demonstr√°mos tamb√©m que a inibi√ß√£o do miR-99a-5p nas MC3T3 fomentou o aumento de express√£o da raz√£o OPG/RANKL ao n√≠vel do mRNA e que o sobrenadante recolhido a partir dessas c√©lulas inibe a diferencia√ß√£o das RAW 264.7 em osteoclastos. Adicionalmente, os resultados mostram que a express√£o do miR-99a-5p varia ao longo do tempo na medula √≥ssea de ratos ap√≥s uma les√£o √≥ssea de defeito cr√≠tico. Finalmente, os resultados obtidos a partir de amostras humanas de pacientes com fractura de fragilidade e diagnosticados com osteoporose mostraram que estes apresentam n√≠veis mais elevados de express√£o do miR-99a-5p comparativamente ao controlo (amostras de pacientes com osteoartrite). Tendo em conta os resultados obtidos ao longo deste trabalho, conclu√≠mos que o miR-99a-5p √© um regulador cr√≠tico da diferencia√ß√£o osteog√©nica. No futuro, a modula√ß√£o dos n√≠veis do miR-99a-5p no osso pode ser utilizada como uma estrat√©gia que tem como objetivo restabelecer a homeostase √≥ssea

    Mushroom ő≤-glucan and polyphenol formulations as natural immunity boosters and balancers: nature of the application

    Get PDF
    Mushrooms are experiencing a kind of renaissance as a part of the contemporary human diet. These valuable organisms are more than food, they fi t in perfectly as a novel market group known as nutra-mycoceuticals. Immune-balancing mushroom dietary fibers and secondary metabolites such as polyphenols are the main focus of the healthcare industry. Wellness and cosmetic companies are increasingly using mushroom extracts rich in these ingredients. This review considers the basic molecular immunomodulatory mechanisms of action of the most commonly used mushroom dietary fibers, ő≤-glucans. The literature data on their bioavailability, metabolic transformations, preclinical and human clinical research, and safety are discussed. Immunomodulatory mechanisms of polyphenol ingredients are also considered. These molecules present great potential in the design of the new immunity balancer formulations according to their widespread structural diversity. Finally, we draw attention to the perspectives of modern trends in mushroom nutraceutical and cosmeceutical formulations to strengthen and balance immunity

    Untersuchungen zur √Ątiologie, dem klinischen Bild sowie M√∂glichkeiten der Therapie der Neuropathie des Nervus tibialis bei Deutsch-Holstein-K√ľhen

    Get PDF
    Einleitung: Periphere Neuropathien sind h√§ufige neurologische Erkrankungen des Rindes. Dabei stellt die Sch√§digung des Nervus tibialis (Tibialis-Neuropathie; TN) neben Klauenerkrankungen eine h√§ufige Lahmheitsursache bei Milchk√ľhen post partum dar. Erkrankungen des Bewegungsapparates z√§hlen neben Erkrankungen des Euters und Fruchtbarkeitsst√∂rungen zu den Hauptabgangsursachen von Milchk√ľhen. Lahmheiten sind Ausdruck von Schmerzen und beeintr√§chtigen somit ma√ügeblich das Tierwohl. Dar√ľber hinaus f√ľhren sie zu wirtschaftlichen Verlusten. Weiterhin werden periphere Neuropathien h√§ufig nicht als solche erkannt oder deren Prognose meist zu schlecht eingesch√§tzt. Dies f√ľhrt zu einem fr√ľhzeitigen Abgang der Tiere, was wiederum unwirtschaftlich ist. Ziele der Untersuchung: Im ersten Schritt sollte anhand einer Literatur√ľbersicht ein √úberblick √ľber allgemeing√ľltige Grundlagen der Neurologie sowie die klinische Auspr√§gung spezieller peripherer Neuropathien beim Rind gewonnen werden. Im zweiten Schritt sollten auf Grundlage einer prospektiven Fallserie Aussagen zum klinischen Bild, zur √Ątiologie und zu Therapie und Prognose der TN getroffen werden. Tiere, Material und Methoden: In die Fallserie wurden von Januar 2013 bis Oktober 2017 prospektiv insgesamt 88 Deutsch-Holstein-K√ľhe mit einseitiger (ETN, n = 71) und beidseitiger (BTN, n = 17) TN eingeschlossen. Einschlusskriterium war das Vorliegen deutlichen √úberk√∂tens eines Fesselgelenks einer Hintergliedma√üe in der Bewegung. Die Tiere stammten aus 31 verschiedenen Betrieben in Brandenburg (n = 2), Sachsen (n = 21), Sachsen-Anhalt (n = 3) und Th√ľringen (n = 5) und wurden in 50 F√§llen station√§r sowie in 38 F√§llen im Rahmen von Bestandsbesuchen vorgestellt. Die Studientiere wurden retrospektiv vier Gruppen zugeteilt, abh√§ngig davon, ob eine spontane Ausheilung eintrat, ob behandelt wurde und welche Art der Behandlung gew√§hlt wurde: Gruppe Spontan, spontane Ausheilung innerhalb 48 Stunden; Gruppe 0Cast, keine Behandlung und keine Ausheilung innerhalb 48 Stunden; Gruppe StV, Behandlung mit Dexamethason und St√ľtzverband; Gruppe Cast, Behandlung mit Dexamethason und Kunstharzverband. Nach Ausschluss von 20 Tieren aufgrund fehlerhafter Dokumentation der Tiernummern oder fr√ľhzeitigen Abgangs, weshalb in diesen F√§llen keine Aussage zu einer m√∂glichen Ausheilung der TN getroffen werden konnte, ergaben sich zur Auswertung Datens√§tze von insgesamt 68 K√ľhen (56 ETN, 12 BTN). Deren Aufteilung auf die vier Gruppen war wie folgt: Spontan, 5 ETN; 0Cast, 8 ETN, 3 BTN; StV, 3 ETN; Cast, 40 ETN, 9 BTN. Die Tiere der Gruppe Cast wurden entweder station√§r (CastKlin; n = 32, 24 ETN, 8 BTN) oder im Herkunftsbetrieb (CastBetr; n = 17, 16 ETN, 1 BTN) behandelt. Zur Erstvorstellung erfolgte au√üerdem eine umfassende Datenerhebung zu Vorbericht, klinischer Symptomatik (Einteilung in drei Paresegrade) sowie die labordiagnostische Untersuchung des aus der Vena jugularis entnommenen Blutes. Neben der t√§glichen Kontrolle der station√§r aufgenommenen Tiere in den ersten 14 Tagen wurden alle behandelten Tiere zu f√ľnf Zeitpunkten (14, 21, 28, 42, 56 Tage nach Erstvorstellung) nachuntersucht. Zur Abschlussuntersuchung an Tag 56 erfolgte eine erneute labordiagnostische Untersuchung des Blutes. Bis zum Studienabschluss im Oktober 2021 wurde in regelm√§√üigen Abst√§nden der Status der Studientiere erfragt. Ergebnisse: Im angegebenen Untersuchungszeitraum trat bei 2,2 % der aufgrund einer Erkrankung des Bewegungsapparates vorgestellten Deutsch-Holstein-K√ľhe eine TN auf. Die ETN war vorwiegend post partum nach Dystokie oder infolge vermehrten seitlichen Liegens aufgrund einer Grunderkrankung aufgetreten. K√ľhe mit BTN waren vor allem im Zeitraum der ersten Brunst mit Anzeichen einer zentralen Nachhandparese vorgestellt worden. Bei fast allen untersuchten Tieren wurden an Tag 0 erh√∂hte Aktivit√§ten der Muskelenzyme Kreatinkinase (CK; ETN: 98 %, BTN: 100 %) und Aspartataminotransferase (AST; ETN: 89 %, BTN: 100 %) beobachtet. Nach Behandlung der ETN war die ermittelte Ausheilungsrate deutlich h√∂her als ohne Behandlung (Cast 98 % und StV 100 % vs. 0Cast 62 %). Bei den BTN-Tieren fiel dieser beobachtete Unterschied nicht so deutlich aus (78 % vs. 67 %). Insgesamt war nach Ausheilung der TN die ermittelte √úberlebensdauer h√∂her als ohne Ausheilung (545 Tage vs. 100 Tage). Zur Abschlussuntersuchung hatten sich bei den Tieren mit ausgeheilter ETN die CK- und AST-Aktivit√§ten wieder dem Referenzbereich angen√§hert (CK: von 434 U/l auf 152 U/l; AST: von 169 U/l auf 77 U/l). Schlussfolgerungen: Die TN ist eine regelm√§√üig vorkommende und somit relevante Erkrankung von Deutsch-Holstein-K√ľhen im Einzugsgebiet der Klinik f√ľr Klauentiere der Veterin√§rmedizinischen Fakult√§t Leipzig. ETN und BTN sind als eigenst√§ndige Erkrankungen anzusehen, da sie sich ma√ügeblich in √Ątiologie, klinischem Bild und Prognose unterscheiden. Die TN geht mit einer Traumatisierung der ausgefallenen Muskulatur einher und die Stabilisierung der Gliedma√üe in physiologsicher Position mittels Cast oder Verband wirkt sich, besonders ab einem Paresegrad 2, positiv auf die Ausheilung aus. Eine genaue Differenzierung zwischen neurogener und myogener Parese ist nur mit weiterf√ľhrenden Diagnostika wie Elektrodiagnostik und Neurosonographie m√∂glich. Besonders bei ETN scheint nur ein geringgradiger Nervenschaden zugrunde zu liegen, sodass die Prognose g√ľnstig und eine Therapie aus wirtschaftlicher Sicht zu empfehlen ist. Da das Wohlbefinden der Tiere durch eine TN aufgrund von Schmerzen und Bewegungseinschr√§nkung nachweislich gest√∂rt ist, sollte die Erkrankung in den Fokus der Inzidenz- und Pr√§valenzanalyse im Rahmen der tier√§rztlichen Bestandsbetreuung genommen werden.:1. EINLEITUNG 2. LITERATUR√úBERSICHT 2.1 Pr√§ambel 2.2 L√§hmungen vom peripheren Typ im Gliedma√üenbereich des Rindes. Teil 1: Allgemeine Ursachen und spezielle L√§hmungen an Vorder- und Hintergliedma√üen (Publikation 1) 2.3 L√§hmungen vom peripheren Typ im Gliedma√üenbereich des Rindes. Teil 2: Diagnostik, Prognose und therapeutisches Vorgehen (Publikation 2) 2.4 Schmerz als Symptom einer Neuropathie ‚Äď neuropathischer Schmerz 2.5 Weiterf√ľhrende Diagnostik als Ausblick 2.5.1 Elektrodiagnostik 2.5.2 Brightness-Mode-Sonographie peripherer Nerven und der dazugeh√∂rigen Muskulatur 2.6 Zusammenfassende Schlussfolgerungen aus der Literaturrecherche 3. MATERIAL UND METHODEN 3.1 Pr√§ambel 3.2 Patientengut 3.3 Studienprotokoll und Gruppenzuteilung 3.3.1 Erstuntersuchung 3.3.1.1 Anamnese 3.3.1.2 Klinische Untersuchung 3.3.1.3 Weiterf√ľhrende Labordiagnostik 3.3.1.4 Herleitung einer m√∂glichen √Ątiologie der Tibialis-Neuropathie aus Ergebnissen der Erstuntersuchung 3.3.2 Behandlung 3.3.2.1 Anlegen des Kunstharzverbandes 3.3.2.2 Medikament√∂se Behandlung 3.3.3 Station√§re Aufnahme 3.3.4 Nachuntersuchungen und Therapieabschluss 3.3.4.1 Folgeanamnese Einzeltier 3.3.4.2 Klinische Folgeuntersuchung 3.3.4.3 Verbandswechselschema 3.3.4.4 Dokumentation von Druckstellen 3.3.4.5 Abschlussuntersuchung 3.3.5 Studienabschluss 3.4 Foto- und Videodokumentation 3.5 Statistik 4. PUBLIKATION 3 5. PUBLIKATION 4 6. WEITERE ERGEBNISSE 6.1 Pr√§ambel 6.2 Zusammenhang zwischen Erkrankungsdauer und Paresegrad zur Erstuntersuchung 6.3 Einfluss des Betreuungsmanagements auf die Auspr√§gung von Druckstellen w√§hrend der Behandlung mit Verband 6.3.1 K√ľhe mit einseitiger, ausgeheilter Tibialis-Neuropathie und initialer Behandlung mit Kunstharzverband in der Klinik 6.3.2 K√ľhe mit einseitiger, ausgeheilter Tibialis-Neuropathie und initialer Behandlung mit Kunstharzverband im Betrieb 6.3.3 K√ľhe mit beidseitiger, ausgeheilter Tibialis-Neuropathie und initialer Behandlung mit Kunstharzverband in der Klinik und im Betrieb 7. DISKUSSION 7.1 Studiendesign und Auswahl der Studientiere 7.2 √Ątiologie der Tibialis-Parese 7.2.1 Tibialis-Neuropathie ‚Äď neurogene Parese 7.2.2 Fibrill√§re Ruptur der Muskulatur ‚Äď myogene Parese 7.3 Angewandtes Therapieschema 7.3.1 Antiphlogistika 7.3.2 Verband 7.3.2.1 Verbandsart und Hilfsmittel 7.3.2.2 Verhinderung von Komplikationen 7.4 Wirtschaftliche Aspekte einer Therapie 7.5 M√∂glichkeiten zur Pr√§vention 7.6 Ausblick: Kl√§rung offener Fragen durch Elektrodiagnostik und Neurosonographie 8. ZUSAMMENFASSUNG 9. SUMMARY 10. LITERATURVERZEICHNIS 11. ANHANG 12. DANKSAGUN

    Preparation, modification, and clinical application of porous tantalum scaffolds

    Get PDF
    Porous tantalum (Ta) implants have been developed and clinically applied as high-quality implant biomaterials in the orthopedics field because of their excellent corrosion resistance, biocompatibility, osteointegration, and bone conductivity. Porous Ta allows fine bone ingrowth and new bone formation through the inner space because of its high porosity and interconnected pore structure. It contributes to rapid bone integration and long-term stability of osseointegrated implants. Porous Ta has excellent wetting properties and high surface energy, which facilitate the adhesion, proliferation, and mineralization of osteoblasts. Moreover, porous Ta is superior to classical metallic materials in avoiding the stress shielding effect, minimizing the loss of marginal bone, and improving primary stability because of its low elastic modulus and high friction coefficient. Accordingly, the excellent biological and mechanical properties of porous Ta are primarily responsible for its rising clinical translation trend. Over the past 2 decades, advanced fabrication strategies such as emerging manufacturing technologies, surface modification techniques, and patient-oriented designs have remarkably influenced the microstructural characteristic, bioactive performance, and clinical indications of porous Ta scaffolds. The present review offers an overview of the fabrication methods, modification techniques, and orthopedic applications of porous Ta implants
    • ‚Ķ
    corecore