Biodegradable Electrospun Conduit with Aligned Fibers Based on Poly(lactic-co-glycolic Acid) (PLGA)/Carbon Nanotubes and Choline Bitartrate Ionic Liquid.

Functionally active aligned fibers are a promising approach to enhance neuro adhesion and guide the extension of neurons for peripheral nerve regeneration. Therefore, the present study developed poly(lactic-co-glycolic acid) (PLGA)-aligned electrospun mats and investigated the synergic effect with carbon nanotubes (CNTs) and Choline Bitartrate ionic liquid (Bio-IL) on PLGA fibers. Morphology, thermal, and mechanical performances were determined as well as the hydrolytic degradation and the cytotoxicity. Results revealed that electrospun mats are composed of highly aligned fibers, and CNTs were aligned and homogeneously distributed into the fibers. Bio-IL changed thermal transition behavior, reduced glass transition temperature (Tg), and favored crystal phase formation. The mechanical properties increased in the presence of CNTs and slightly decreased in the presence of the Bio-IL. The results demonstrated a decrease in the degradation rate in the presence of CNTs, whereas the use of Bio-IL led to an increase in the degradation rate. Cytotoxicity results showed that all the electrospun mats display metabolic activity above 70%, which demonstrates that they are biocompatible. Moreover, superior biocompatibility was observed for the electrospun containing Bio-IL combined with higher amounts of CNTs, showing a high potential to be used in nerve tissue engineering.

Production of a Bioink Containing Decellularized Spinal Cord Tissue for 3D Bioprinting.

For the past few years, three-dimensional (3D) bioprinting has emerged as a promising approach in the field of regenerative medicine. This technique allows for the production of 3D scaffolds to support cell transplantation due to its ability to mimic the extracellular environment. One alternative to enhancing cell adhesion, survival, and proliferation is the use of decellularized extracellular matrix as a bioink component. The aim of this study was to produce a bioink using lyophilized rat decellularized spinal cord tissue (DSCT) for 3D bioprinting of nervous tissue. DNA quantification, hematoxylin and eosin and DAPI staining indicated that 1% sodium dodecyl sulfate and 9 h processing were effective in removing the cells from the spinal cord samples. The cell viability assay showed that the decellularized matrix is not cytotoxic for PC12 cells. The hydrogel containing DSCT, alginate, and gelatine used as the base for the bioink has a shear thinning behavior and low G″/G' ratio, allowing for good printability without compromising cell viability after 3D bioprinting. The bioink supported long-term PC12 cell survival, with 93% of live cells 4 weeks after printing, and stimulated the production of laminin-1 and neurofilament-M. This bioink, therefore, represents an easily available biomaterial for central nervous system tissue engineering.

Intenção de se vacinar contra a COVID-19 e hesitação vacinal no Sul do Brasil: prevalência e fatores associados / Intention to get vaccinated against COVID-19 and vaccine hesitation in Southern Brazil: prevalence and associated factors

INTRODUÇÃO: A vacinação contra a COVID-19 é um dos principais recursos de saúde pública para mitigar a pandemia globalmente. As taxas de vacinação dependem diretamente da aceitação e adesão da população. Sabese que a aceitação vacinal é muito heterogênea entre as diferentes regiões do globo, mas há poucos estudos avaliando a percepção geral das vacinas contra a COVID-19 no Brasil. OBJETIVO: Avaliar a intenção de vacinação contra COVID-19 entre moradores do Rio Grande do Sul (RS), Brasil, durante o início da campanha de vacinação no país, e identificar fatores associados à hesitação vacinal. MÉTODOS: Foi realizada uma pesquisa com coleta de dados online, que recrutou um total de 953 respondentes. O questionário foi divulgado em mídias digitais de março a maio de 2021, por meio do método de amostragem bola de neve. RESULTADOS: Aproximadamente 96% da amostra informou que pretendia tomar a vacina contra a COVID-19. A hesitação vacinal foi positivamente associada a ser casado, ter filhos e ser mais velho. Indivíduos sem intenção de se vacinar também foram mais propensos a não respeitar o distanciamento social e outras ações de proteção individual. CONCLUSÕES: Nossos achados estão de acordo com os dados atuais de cobertura vacinal no RS. Embora o Brasil esteja apresentando taxas de vacinação superiores à maioria dos países do mundo, devemos atentar para os grupos populacionais que não aderem à vacinação. Reforçamos a importância da constante divulgação científica e educação em saúde para toda a população como aliadas no fortalecimento das políticas públicas de vacinação.(AU)

INTRODUCTION: The vaccination against COVID-19 is one of the major public health resources to mitigate the global pandemic. Vaccination rates directly depends on the acceptance and adherence by the population. It is known that the vaccine acceptancy is very heterogeneous among different regions of the globe, but there are few studies evaluating the general perception of COVID-19 vaccines in Brazil. AIM: To evaluate the intention of vaccination against COVID-19 among residents of Rio Grande do Sul (RS), Brazil, during the beginning of the campaign in the country, and to identify factors associated with vaccine hesitancy. METHODS: An online survey was conducted, ending in a sample of 953 respondents. The questionnaire was divulgated through digital medias from March to May 2021, via a snowball sampling method. RESULTS: Approximal 96% of the sample informed they intended to take COVID-19 vaccine. Vaccine hesitancy was positively associated with being married, having children, and being older. Subjects with no intention to get vaccinated were also more likely to not respect social distancing and other individual protection actions. CONCLUSIONS: Our findings are in line with current vaccination coverage data in RS. Although Brazil is showing vaccination rates higher than most countries in the world, we must pay attention to population groups that do not adhere to vaccination. We reinforce the importance of constant science communication and health education for the whole population as allies in strengthening public policies for vaccination.(AU)

INTRODUCCIÓN: La vacunación contra el COVID-19 es uno de los principales recursos de salud pública para mitigar la pandemia. Las tasas de vacunación dependen directamente de la aceptación y adherencia por parte de la población. Se sabe que la aceptación de la vacuna es muy heterogénea entre las diferentes regiones del mundo, pero hay pocos estudios que evalúen la percepción general de las vacunas contra la COVID-19 en Brasil. OBJETIVO: Evaluar la intención de vacunación contra la COVID-19 entre los residentes de Rio Grande do Sul (RS), Brasil, e identificar factores asociados a la reticencia vacunal. MÉTODOS: Se realizó una encuesta en línea, finalizando en una muestra de 953 encuestados. El cuestionario fue divulgado a través de medios digitales de marzo a mayo de 2021, mediante un método de muestreo de bola de nieve. RESULTADOS: Aproximadamente 96% de la muestra informó que tenía la intención de recibir la vacuna COVID-19. La reticencia a la vacuna se asoció positivamente con estar casado, tener hijos y ser mayor. Los sujetos sin intención de vacunarse también tenían más probabilidades de no respetar el distanciamiento social y otras medidas de protección individual. CONCLUSIONES: Nuestros hallazgos están en línea con los datos actuales de cobertura de vacunación en RS. Debemos prestar atención a los grupos de población que no se adhieren a la vacunación. Reforzamos la importancia de la comunicación científica constante y la educación en salud para toda la población como aliados en el fortalecimiento de las políticas públicas de vacunación.(AU)

Therapeutic Effects of Physical Exercise and the Mesenchymal Stem Cell Secretome by Modulating Neuroinflammatory Response in Multiple Sclerosis.

Multiple Sclerosis (MS) is a neurodegenerative, demyelinating, and chronic inflammatory disease characterized by Central Nervous System (CNS) lesions that lead to high levels of disability and severe physical and cognitive disturbances. Conventional therapies are not enough to control the neuroinflammatory process in MS and are not able to inhibit ongoing damage to the CNS. Thus, the secretome of mesenchymal stem cells (MSC-S) has been postulated as a potential therapy that could mitigate symptoms and disease progression. We considered that its combination with physical exercise (EX) could induce superior effects and increase the MSC-S effectiveness in this condition. Recent studies have revealed that both EX and MSC-S share similar mechanisms of action that mitigate auto-reactive T cell infiltration, regulate the local inflammatory response, modulate the proinflammatory profile of glial cells, and reduce neuronal damage. Clinical and experimental studies have reported that these treatments in an isolated way also improve myelination, regeneration, promote the release of neurotrophic factors, and increase the recruitment of endogenous stem cells. Together, these effects reduce disease progression and improve patient functionality. Despite these results, the combination of these methods has not yet been studied in MS. In this review, we focus on molecular elements and cellular responses induced by these treatments in a separate way, showing their beneficial effects in the control of symptoms and disease progression in MS, as well as indicating their contribution in clinical fields. In addition, we propose the combined use of EX and MSC-S as a strategy to boost their reparative and immunomodulatory effects in this condition, combining their benefits on synaptogenesis, neurogenesis, remyelination, and neuroinflammatory response. The findings here reported are based on the scientific evidence and our professional experience that will bring significant progress to regenerative medicine to deal with this condition.

Characterization, Cytotoxicity and Anti-Inflammatory Effect Evaluation of Nanocapsules Containing Nicotine.

(1) Background: Nanotechnology is an emerging field that can be applied in the biomedical area. In this study, Eudragit nanocapsules (NCs) containing nicotine were produced. Nicotine is the main alkaloid found in tobacco and has anti-inflammatory properties. NCs containing nicotine may be used as an adjuvant therapy in the treatment of inflammation in the central nervous system. (2) Methods: Nanocapsules were prepared by the interfacial deposition of the pre-formed polymer method and characterized in terms of zeta potential, diameter, polydispersity index, pH, encapsulation efficiency (EE), stability and sustained release profile. In vitro tests with the PC12 cell line were performed, such as MTT, LIVE/DEAD and ELISA assays, to verify their cytotoxic and anti-inflammatory effects. (3) Results: The nanocapsules presented satisfactory values of the characterization parameters; however, poor encapsulation was obtained for nicotine (8.17% ± 0.47). The in vitro tests showed that the treatment with nanocapsules reduced cell viability, which suggests that the Eudragit or the amount of polymer on top of the cells may be detrimental to them, as the cells were able to survive when treated with bulk nicotine. ELISA showed an increment in the expression of IL-6 and IL-1ß, corroborating the hypothesis that NCs were toxic to the cells because of the increase in the levels of these pro-inflammatory cytokines. (4) Conclusions: This study demonstrates that NCs of Eudragit present toxicity. It is therefore necessary to improve NC formulation to obtain better values for the encapsulation efficiency and reduce toxicity of these nanodevices.

Development of a conduit of PLGA-gelatin aligned nanofibers produced by electrospinning for peripheral nerve regeneration.

A promising alternative to conventional nerve grafting is the use of artificial grafts made from biodegradable and biocompatible materials and support cells. The aim of this study has been to produce a biodegradable nerve conduit and investigate the cytocompatibility with stem cells and its regeneration promoting properties in a rat animal model. A poly (lactic-co-glycolic acid) (PLGA) conduit of aligned nanofibers was produced by the electrospinning method, functionalized with gelatin and seeded either with mouse embryonic stem cells (mESCs) or with human mesenchymal stem cells (SHED). The cell proliferation and viability were analyzed in vitro. The conduits were implanted in a rat model of sciatic nerve lesion by transection. The functional recovery was monitored for 8 weeks using the Sciatic Functional Index (SFI) and histological analyses were used to assess the nerve regeneration. Scaffolds of aligned PLGA fibers with an average diameter of 0.90 ± 0.36 µm and an alignment coefficient of 0.817 ± 0.07 were produced. The treatment with gelatin increased the fiber diameter to 1.05 ± 0.32 µm, reduced the alignment coefficient to 0.655 ± 0.045 and made the scaffold very hydrophilic. The cell viability and Live/dead assay showed that the stem cells remained viable and proliferated after 7 days in culture. Confocal images of phalloidin/DAPI staining showed that the cells adhered and proliferated widely, in fully adaptation with the biomaterial. The SFI values of the group that received the conduit were similar to the values of the control lesioned group. In conclusion, conduits composed of PLGA-gelatin nanofibers were produced and promoted a very good interaction with the stem cells. Although in vitro studies have shown this biomaterial to be a promising biomaterial for the regeneration of nerve tissue, in vivo studies of this graft have not shown significant improvements in nerve regeneration.

Repeated three-hour maternal deprivation as a model of early-life stress alters maternal behavior, olfactory learning and neural development.

Early life stress such as physical abuse, trauma or neglect during a critical period of development can elicit negative long-lasting effects on health. Neonatal maternal deprivation (MD) is a stressful event capable of triggering structural and neurobiological changes in Central Nervous System (CNS) development during proliferative and migratory cell differentiation. In this study, we investigated the maternal behavior of lactating rats submitted to protocol of chronic neonatal maternal deprivation (MD) during postnatal day (PND) 1 until 10. We analyzed the effects of the MD in the olfactory memory and cellular proliferation and differentiation in the hippocampus and olfactory bulb in Wistar rat pups on 7, 11 and 21 days postpartum. Analysis in active neurons, cellular differentiation and proliferation, were marked and evaluated by flow cytometry in tissue samples of hippocampi and olfactory bulb. Our results demonstrated an increase in maternal behavior immediately after dam's return to the home-cage in MD group compared to the non-deprived group. In addition, MD pups spent more time (higher latency) to identify the nest odor in comparison to the non-deprived rat pups in the olfactory learning task and showed a significant delay in the neural differentiation and proliferation in the hippocampus and olfactory bulb. These results reveal that disruptions in the mother-infant bonding by the MD induce changes in maternal behavior and interaction with the offspring that could be leading to delayed CNS development and significant impairment in offspring's olfactory learning.

Electrospun and Electrosprayed Scaffolds for Tissue Engineering.

Electrospinning and electrospraying technologies provide an accessible and universal synthesis method for the continuous preparation of nanostructured materials. This chapter introduces recent uses of electrospun and electrosprayed scaffolds for tissue regeneration applications. More recent in vitro and in vivo of electrospun fibers are also discussed in relation to soft and hard tissue engineering applications. The focus is made on the bone, vascular, skin, neural and soft tissue regeneration. An introduction is presented regarding the production of biomaterials made by synthetic and natural polymers and inorganic and metallic materials for use in the production of scaffolds for regenerative medicine. For this proposal, the following techniques are discussed: electrospraying, co-axial and emulsion electrospinning and bio-electrospraying. Tissue engineering is an exciting and rapidly developing field for the understanding of how to regenerate the human body.