Functionalized Hydrogels for Cartilage Repair: The Value of Secretome-Instructive Signaling

Cartilage repair has been a challenge in the medical field for many years. Although treatments that alleviate pain and injury are available, none can effectively regenerate the cartilage. Currently, regenerative medicine and tissue engineering are among the developed strategies to treat cartilage injury. The use of stem cells, associated or not with scaffolds, has shown potential in cartilage regeneration. However, it is currently known that the effect of stem cells occurs mainly through the secretion of paracrine factors that act on local cells. In this review, we will address the use of the secretome—a set of bioactive factors (soluble factors and extracellular vesicles) secreted by the cells—of mesenchymal stem cells as a treatment for cartilage regeneration. We will also discuss methodologies for priming the secretome to enhance the chondroregenerative potential. In addition, considering the difficulty of delivering therapies to the injured cartilage site, we will address works that use hydrogels functionalized with growth factors and secretome components. We aim to show that secretome-functionalized hydrogels can be an exciting approach to cell-free cartilage repair therapy.     

Biochemical characterisation and application of lipases produced by Aspergillus sp. on solid‐state fermentation using three substrates

Lipase from Aspergillus sp. obtained by solid‐state fermentation (SSF) on wheat bran (LWB), soybean bran (LSB) and soybean bran combined with sugarcane bagasse (LSBBC) were 67.5, 58 and 57.3 U of crude lipase per gram substrate, respectively. The optimum pH of activity and stability of the LWB was between 8 and 9, and the optimum temperature of activity and stability was 50 °C and up to 60 °C, respectively. The LSB and LSBBC showed two peaks of optimum pH (4 and 6) and optimal values of temperature and stability at 50 °C. The LSB was stable in the pH range of 6–7, while LSBBC in the range of pH 4–7. All the enzymes show activities on p‐nitrophenyl esters (butyrate, laurate and palmitate). LWB stood out either on the hydrolysis of sunflower oil, presenting 66.1% of the activity over commercial lipase and on the esterification of oleic acid and ethanol, surpassing the activities of the commercial lipases studied. The thin layer chromatography showed that LWB and LSB have produced ethyl esters from corn oil, while LWB produced it from sunflower oil.     

Production of fungal lipases using wheat bran and soybean bran and incorporation of sugarcane bagasse as a co-substrate in solid-state fermentation

Fungal strains were screened for lipase producing activities and 10 strains were classified as good producers. Aspergillus sp., Fusarium sp., and Penicillium sp. exhibited the highest activities when fermented in wheat bran (WB) and soybean bran (SB). No fungal growth was observed using sugarcane bagasse (CB). An experimental design was applied to incorporate CB into the fermentation process for lipase production by Aspergillus sp. and Penicillium sp., and to evaluate the best moisture content for the substrate. Strains studied achieved maximum lipase activities with 25% CB combined with 75% WB or SB at 40% moisture content. The highest lipase activities were observed for WB and SB, and for SB combined with CB using Aspergillus sp. Fermentation of 96 h was the optimum period for enzyme production.     

Burial grounds’ impact on groundwater and public health: an overview

The most common practice for disposal of dead bodies is inhumation in soil, which favours interactions with the surrounding environment and returns nutrients to the life cycle. However, when the burial ground is located where hydrogeological, geological and climatic conditions are not favourable to the process, contamination of soils and groundwater may occur, and decomposition may be inhibited, leading to social, economic and political problems. The most critical parameters when assessing the pollution potential of a burial ground are inhumation depth, geological formation, depth of the water table, density of inhumations, soil type and climate. Considering that, this paper presents an overview of the potential threat that cemeteries can pose, analysing and discussing the influence of the main variables causing environmental impacts and public health risks.     

From Molecules to Behavior in Long-Term Inorganic Mercury Intoxication: Unraveling Proteomic Features in Cerebellar Neurodegeneration of Rats

Mercury is a severe environmental pollutant with neurotoxic effects, especially when exposed for long periods. Although there are several evidences regarding mercury toxicity, little is known about inorganic mercury (IHg) species and cerebellum, one of the main targets of mercury associated with the neurological symptomatology of mercurial poisoning. Besides that, the global proteomic profile assessment is a valuable tool to screen possible biomarkers and elucidate molecular targets of mercury neurotoxicity; however, the literature is still scarce. Thus, this study aimed to investigate the effects of long-term exposure to IHg in adult rats’ cerebellum and explore the modulation of the cerebellar proteome associated with biochemical and functional outcomes, providing evidence, in a translational perspective, of new mercury toxicity targets and possible biomarkers. Fifty-four adult rats were exposed to 0.375 mg/kg of HgCl₂ or distilled water for 45 days using intragastric gavage. Then, the motor functions were evaluated by rotarod and inclined plane. The cerebellum was collected to quantify mercury levels, to assess the antioxidant activity against peroxyl radicals (ACAPs), the lipid peroxidation (LPO), the proteomic profile, the cell death nature by cytotoxicity and apoptosis, and the Purkinje cells density. The IHg exposure increased mercury levels in the cerebellum, reducing ACAP and increasing LPO. The proteomic approach revealed a total 419 proteins with different statuses of regulation, associated with different biological processes, such as synaptic signaling, energy metabolism and nervous system development, e.g., all these molecular changes are associated with increased cytotoxicity and apoptosis, with a neurodegenerative pattern on Purkinje cells layer and poor motor coordination and balance. In conclusion, all these findings feature a neurodegenerative process triggered by IHg in the cerebellum that culminated into motor functions deficits, which are associated with several molecular features and may be related to the clinical outcomes of people exposed to the toxicant.     

High eEF1A1 Protein Levels Mark Aggressive Prostate Cancers and the In Vitro Targeting of eEF1A1 Reveals the eEF1A1–actin Complex as a New Potential Target for Therapy

Although the eukaryotic elongation factor eEF1A1 plays a role in various tumours, there is little information on its prognosis/therapeutic value in prostate carcinoma. In high-grade and castration-resistant prostate carcinoma (CRPC), the identification of novel therapeutic markers/targets remains a priority. The expression of eEF1A1 protein was determined in formalin-fixed, paraffin-embedded prostate cancer and hyperplasia tissue by IHC. The role of eEF1A1 was investigated in a cellular model using a DNA aptamer (GT75) we previously developed. We used the aggressive CRPC cancer PC-3 and non-tumourigenic PZHPV-7 lines. Cytotoxicity was measured by the MTS assay and eEF1A1 protein levels by in-cell Western assays. The mRNA levels of eEF1A1 were measured by qPCR and ddPCR. Higher expression of eEF1A1 was found in Gleason 7–8 compared with 4–6 tissues (Gleason ≥ 7, 87% versus Gleason ≤ 6, 54%; p = 0.033). Patients with a high expression of eEF1A1 had a worse clinical outcome. In PC-3, but not in PZHPV-7, GT75 decreased cell viability and increased autophagy and cell detachment. In PC-3 cells, but not in PZHPV-7, GT75 mainly co-localised with the fraction of eEF1A1 bound to actin. Overexpression of the eEF1A1 protein can identify aggressive forms of prostate cancer. The targeting of eEF1A1 by GT75 impaired cell viability in PC-3 cancer cells but not in PZHPV-7 non-tumourigenic cells, indicating a specific role for the protein in cancer survival. The eEF1A1–actin complexes appear to be critical for the viability of PC-3 cancer cells, suggesting that eEF1A1 may be an attractive target for therapeutic strategies in advanced forms of prostate cancer.     

Parameters effect on proton conductivity to obtain chitosan membranes for use as electrolytes in PEMFC

The chitosan biopolymer can be used as a proton‐conducting membrane in proton‐exchange membrane fuel cell. In the forms that they have normally obtained and tested, chitosan membranes typically show poor performance in conduction of protons, requiring modifications in the structure of the biopolymer or blending with other polymers to increase its proton conductivity. The present work investigates the individual properties of chitosan and relates them to the proton conductivity performance of membranes composed of this polymer. Evaluation was made of the effects of variables such as the degree of deacetylation (DD) and the molar mass (Mv) of chitosan membranes without addition of any other polymer. The DD and Mv values of the chitosan used to produce membranes determined the proton conduction, with lower DD and higher Mv resulting in higher conductivity. The thicker membranes presented greater crystallinity, with conductivity between 2.0 × 10^?4 and 1.8 × 10^?3 S cm^?1. The characteristic stages of degradation of the chitosan membranes were in the ranges 200 to 300°C and 500 to 600°C, indicating good thermal stability of the material.     

The Influence of the Rebaudioside A Content of Stevia (Stevia rebaudiana Bertoni) on the Determination of Sweetness Equivalence in Bittersweet Chocolates,Using the Time‐Intensity Analysis

The consumption of diet products has increased greatly in recent years. The objectives of the study were to develop a bittersweet chocolate added inulin and stevias with different rebaudioside A contents (60%, 80%, and 97%). Five chocolate samples were formulated with different sucrose concentrations to determine the ideal sucrose concentration for bittersweet chocolate. The use of just‐about‐right scale identified an ideal sucrose concentration of 47.5% (w/w). The sweetness equivalence in sugar‐free bittersweet chocolates was determined by the time–intensity method by 14 selected and trained judges. The data collected during each session of sensory evaluation furnished the following parameters in relation to the sweet stimulus: Imax (maximum intensity recorded), Timax (time at which the maximum intensity was recorded), Area (area of time × intensity curve), and Ttot (total duration time of the stimulus). The time–intensity analysis indicated that the percentages of rebaudioside A did not interfere with the sweetness intensity of the sweetener stevia in bittersweet chocolate and there was no significant difference in the concentrations tested (0.16%, 0.22%, 0.27%) of each stevia, in relation to the parameters evaluated. In addition, the reduction in fat content did not alter the perception of the sweetness intensity of the samples. These results showed important information to research and development of chocolate products. Therefore, the use of the lowest stevia concentration tested (0.16%) is the most indicated for use, since this quantity was sufficient to reach the ideal sweetness of the product, so there was no point in adding more.