Hierarchical Biomaterial Scaffolds for Periodontal Tissue Engineering: Recent Progress and Current Challenges.

The periodontium is a complex hierarchical structure composed of alveolar bone, periodontal ligament, cementum, and gingiva. Periodontitis is an inflammatory disease that damages and destroys the periodontal tissues supporting the tooth. Periodontal therapies aim to regenerate the lost tissues, yet current treatments lack the integration of multiple structural/biochemical instructive cues to induce a coordinated regeneration, which leads to limited clinical outcomes. Hierarchical biomaterial scaffolds offer the opportunity to recreate the organization and architecture of the periodontium with distinct compartments, providing structural biomimicry that facilitates periodontal regeneration. Various scaffolds have been fabricated and tested preclinically, showing positive regenerative results. This review provides an overview of the recent research on hierarchical scaffolds for periodontal tissue engineering (TE). First, the hierarchical structure of the periodontium is described, covering the limitations of the current treatments used for periodontal regeneration and presenting alternative therapeutic strategies, including scaffolds and biochemical factors. Recent research regarding hierarchical scaffolds is highlighted and discussed, in particular, the scaffold composition, fabrication methods, and results from in vitro/in vivo studies are summarized. Finally, current challenges associated with the application of hierarchical scaffolds for periodontal TE are debated and future research directions are proposed.

NGS Data Repurposing Allows Detection of tRNA Fragments as Gastric Cancer Biomarkers in Patient-Derived Extracellular Vesicles.

Transfer RNA fragments (tRFs) have gene silencing effects similarly to miRNAs, can be sorted into extracellular vesicles (EVs) and are emerging as potential circulating biomarkers for cancer diagnoses. We aimed at analyzing the expression of tRFs in gastric cancer (GC) and understanding their potential as biomarkers. We explored miRNA datasets from gastric tumors and normal adjacent tissues (NATs) from TCGA repository, as well as proprietary 3D-cultured GC cell lines and corresponding EVs, in order to identify differentially represented tRFs using MINTmap and R/Bioconductor packages. Selected tRFs were validated in patient-derived EVs. We found 613 Differentially Expressed (DE)-tRFs in the TCGA dataset, of which 19 were concomitantly upregulated in TCGA gastric tumors and present in 3D cells and EVs, but barely expressed in NATs. Moreover, 20 tRFs were expressed in 3D cells and EVs and downregulated in TCGA gastric tumors. Of these 39 DE-tRFs, 9 tRFs were also detected in patient-derived EVs. Interestingly, the targets of these 9 tRFs affect neutrophil activation and degranulation, cadherin binding, focal adhesion and the cell-substrate junction, highlighting these pathways as major targets of EV-mediated crosstalk with the tumor microenvironment. Furthermore, as they are present in four distinct GC datasets and can be detected even in low quality patient-derived EV samples, they hold promise as GC biomarkers. By repurposing already available NGS data, we could identify and cross-validate a set of tRFs holding potential as GC diagnosis biomarkers.

Human cells adapt to translational errors by modulating protein synthesis rate and protein turnover.

Deregulation of tRNAs, aminoacyl-tRNA synthetases (aaRS) or tRNA modifying enzymes, increase the level of protein synthesis errors (PSE) and are associated with several diseases, but the cause-effect mechanisms of these pathologies remain elusive. To clarify the role of PSE in human biology, we have engineered a HEK293 cell line to overexpress a wild type (Wt) tRNASer and two tRNASer mutants that misincorporate serine at non-cognate codon sites. Then, we followed long-term adaptation to PSE of such recombinant cells by analysing cell viability, protein synthesis rate and activation of protein quality control mechanisms (PQC). Engineered cells showed higher level of misfolded and aggregated proteins; activated the ubiquitin-proteasome system (UPS) and the unfolded protein response (UPR), indicative of proteotoxic stress. Adaptation to PSE involved increased protein turnover, UPR up-regulation and altered protein synthesis rate. Gene expression analysis showed that engineered cells presented recurrent alterations in the endoplasmic reticulum, cell adhesion and calcium homeostasis. Herein, we unveil new phenotypic consequences of protein synthesis errors in human cells and identify the protein quality control processes that are necessary for long-term adaptation to PSE and proteotoxic stress. Our data provide important insight on how chronic proteotoxic stress may cause disease and highlight potential biological pathways that support the association of PSE with disease.

Body compassion safeguards against the impact of major life events on binge eating.

Body compassion is a fresh construct that incorporates two multidimensional concepts: body image and self-compassion. Although self-compassion has revealed a protective role against body image and eating-related problems (e.g., binge eating), the study of this specific compassionate competence focused on body image is still largely unexplored. The present study aimed to test two moderation models which hypothesized that body compassion moderates the impacts of (i) the cumulative number and (ii) negative appraisal of major life events on binge eating behaviours, in a sample of 458 women from the Portuguese general population. Results showed that body compassion was negatively associated with major life events and binge eating. Moderation analysis results demonstrated the moderator effect of body compassion on the relationship between major life events (both cumulative number and negative appraisal) and binge eating, accounting for 34% and 33% of the variance of binge eating, respectively. The moderator effect of body compassion was confirmed to low to medium levels of body compassion and, overall, results seem to suggest that, for the same levels of major life events (in number or negative appraisal), women who present higher body compassion present less binge eating symptoms. Although these data are preliminary and need support from a longitudinal design research, current findings appear to be promising by suggesting the relevance of promoting body compassion in prevention and treatment programs for disordered eating attitudes and behaviours.

Codon misreading tRNAs promote tumor growth in mice.

Deregulation of tRNAs, aminoacyl-tRNA synthetases and tRNA modifying enzymes are common in cancer, raising the hypothesis that protein synthesis efficiency and accuracy (mistranslation) are compromised in tumors. We show here that human colon tumors and xenograft tumors produced in mice by two epithelial cancer cell lines mistranslate 2- to 4-fold more frequently than normal tissue. To clarify if protein mistranslation plays a role in tumor biology, we expressed mutant Ser-tRNAs that misincorporate Ser-at-Ala (frequent error) and Ser-at-Leu (infrequent error) in NIH3T3 cells and investigated how they responded to the proteome instability generated by the amino acid misincorporations. There was high tolerance to both misreading tRNAs, but the Ser-to-Ala misreading tRNA was a more potent inducer of cell transformation, stimulated angiogenesis and produced faster growing tumors in mice than the Ser-to-Leu misincorporating tRNA. Upregulation of the Akt pathway and the UPR were also observed. Most surprisingly, the relative expression of both misreading tRNAs increased during tumor growth, suggesting that protein mistranslation is advantageous in cancer contexts. These data highlight new features of protein synthesis deregulation in tumor biology.

Impact of tRNA Modifications and tRNA-Modifying Enzymes on Proteostasis and Human Disease.

Transfer RNAs (tRNAs) are key players of protein synthesis, as they decode the genetic information organized in mRNA codons, translating them into the code of 20 amino acids. To be fully active, tRNAs undergo extensive post-transcriptional modifications, catalyzed by different tRNA-modifying enzymes. Lack of these modifications increases the level of missense errors and affects codon decoding rate, contributing to protein aggregation with deleterious consequences to the cell. Recent works show that tRNA hypomodification and tRNA-modifying-enzyme deregulation occur in several diseases where proteostasis is affected, namely, neurodegenerative and metabolic diseases. In this review, we discuss the recent findings that correlate aberrant tRNA modification with proteostasis imbalances, in particular in neurological and metabolic disorders, and highlight the association between tRNAs, their modifying enzymes, translational decoding, and disease onset.

Home versus in-hospital treatment of outpatients with acute deep venous thrombosis of the lower limbs.

BACKGROUND: Some physicians are still concerned about the safety of treatment at home of patients with acute deep venous thrombosis (DVT). METHODS: We used data from the RIETE (Registro Informatizado de la Enfermedad TromboEmbólica) registry to compare the outcomes in consecutive outpatients with acute lower limb DVT according to initial treatment at home or in the hospital. A propensity score-matching analysis was carried out with a logistic regression model. RESULTS: As of December 2012, 13,493 patients had been enrolled. Of these, 4456 (31%) were treated at home. Patients treated at home were more likely to be male and younger and to weigh more; they were less likely than those treated in the hospital to have chronic heart failure, lung disease, renal insufficiency, anemia, recent bleeding, immobilization, or cancer. During the first week of anticoagulation, 27 patients (0.20%) suffered pulmonary embolism (PE), 12 (0.09%) recurrent DVT, and 51 (0.38%) major bleeding; 80 (0.59%) died. When only patients treated at home were considered, 12 (0.27%) had PE, 4 (0.09%) had recurrent DVT, 6 (0.13%) bled, and 4 (0.09%) died (no fatal PE, 3 fatal bleeds). After propensity analysis, patients treated at home had a similar rate of venous thromboembolism recurrences and a lower rate of major bleeding (odds ratio, 0.4; 95% confidence interval, 0.1-1.0) or death (odds ratio, 0.2; 95% confidence interval, 0.1-0.7) within the first week compared with those treated in the hospital. CONCLUSIONS: In outpatients with DVT, home treatment was associated with a better outcome than treatment in the hospital. These data may help safely treat more DVT patients at home.

[Effectiveness of cleaning or disinfecting the urinary meatus before urinary catheterization: a systematic review]. / Eficácia da limpeza ou desinfeção do meato urinário antes da cateterização urinária: revisão sistemática.

The urinary tract infections associated with catheterization are very common in hospital and home care contexts. Currently there are several recommendations for its prevention, however, when approaching the kind of solute used in the urinary meatus prior to catheterization doubts continue to persist. Thus this study aimed at determining the effectiveness of cleaning the urinary meatus with water or saline comparing to its sterilization through a systematic review and meta-analysis. In order to do so, the principles proposed by the Cochrane Handbook were followed, a critical analysis was conducted by two researchers and the statistical analysis was performed with the use of STATA 11.1. We concluded that the cleaning or disinfection of the urinary canal prior to bladder catheterization is not statistically significant (OR=1.07, CI 95%=0.68-1.68, p=0.779) and that there is some evidence that the use of water/saline reduces rates of UTI (urinary tract infection).

Recent Advances on Electrospun Nanofibers for Periodontal Regeneration.

Periodontitis is an inflammatory infection caused by bacterial plaque accumulation that affects the periodontal tissues. Current treatments lack bioactive signals to induce tissue repair and coordinated regeneration of the periodontium, thus alternative strategies are needed to improve clinical outcomes. Electrospun nanofibers present high porosity and surface area and are able to mimic the natural extracellular matrix, which modulates cell attachment, migration, proliferation, and differentiation. Recently, several electrospun nanofibrous membranes have been fabricated with antibacterial, anti-inflammatory, and osteogenic properties, showing promising results for periodontal regeneration. Thus, this review aims to provide an overview of the current state of the art of these nanofibrous scaffolds in periodontal regeneration strategies. First, we describe the periodontal tissues and periodontitis, as well as the currently available treatments. Next, periodontal tissue engineering (TE) strategies, as promising alternatives to the current treatments, are addressed. Electrospinning is briefly explained, the characteristics of electrospun nanofibrous scaffolds are highlighted, and a detailed overview of electrospun nanofibers applied to periodontal TE is provided. Finally, current limitations and possible future developments of electrospun nanofibrous scaffolds for periodontitis treatment are also discussed.

New Insights in Hydrogels for Periodontal Regeneration.

Periodontitis is a destructive inflammatory disease characterized by microbial infection that damages the tissues supporting the tooth (alveolar bone, gingiva, periodontal ligament, and cementum), ultimately resulting in the loss of teeth. The ultimate goal of periodontal therapy is to achieve the regeneration of all of the periodontal tissues. Thus, tissue engineering approaches have been evolving from simple membranes or grafts to more complex constructs. Hydrogels are highly hydrophilic polymeric networks with the ability to simulate the natural microenvironment of cells. In particular, hydrogels offer several advantages when compared to other forms of scaffolds, such as tissue mimicry and sustained drug delivery. Moreover, hydrogels can maintain a moist environment similar to the oral cavity. Hydrogels allow for precise placement and retention of regenerative materials at the defect site, minimizing the potential for off-target effects and ensuring that the treatment is focused on the specific defect site. As a mechanism of action, the sustained release of drugs presented by hydrogels allows for control of the disease by reducing the inflammation and attracting host cells to the defect site. Several therapeutic agents, such as antibiotics, anti-inflammatory and osteogenic drugs, have been loaded into hydrogels, presenting effective benefits in periodontal health and allowing for sustained drug release. This review discusses the causes and consequences of periodontal disease, as well as the advantages and limitations of current treatments applied in clinics. The main components of hydrogels for periodontal regeneration are discussed focusing on their different characteristics, outcomes, and strategies for drug delivery. Novel methods for the fabrication of hydrogels are highlighted, and clinical studies regarding the periodontal applications of hydrogels are reviewed. Finally, limitations in current research are discussed, and potential future directions are proposed.

Epidemiology of bacteremia in a pediatric population - A 10-year study.

INTRODUCTION: With the widespread introduction of conjugate meningococcal and pneumococcal vaccines, the prevalence and etiology of invasive bacterial infections have changed. We aimed to review all cases of bacteremia in a level II pediatric department over a ten-year period in the post-pneumococcal conjugate vaccine era. METHODS: We reviewed all positive blood cultures (BC) obtained in our department between 2007 and 2016. Results were classified as contaminants, potential pathogens or confirmed pathogens, based on species, number of positive BC in the episode and the patients' medical history. Demographic and clinical data were collected for patients with identified pathogens. RESULTS: A total of 638 positive BC were identified (6.6% of total BC); 120 (1.2%) were considered to represent true bacteremia. The most frequently identified microorganism was Streptococcus pneumoniae (29.2%), with a decrease in the number of cases between 2008 and 2015. Staphylococcus aureus was the second most common organism (19.2%) being 21.7% of these methicillin-resistant. Escherichia coli was the most common isolate in children aged less than three months. CONCLUSION: We found a rate of true bacteremia in children similar to recent studies. Although Streptococcus pneumoniae remains the most common microorganism, its prevalence may be declining. Monitoring microbiological data in children has implications in practice, particularly in local antibiotic prescription.

Design of a microfluidic mixer channel: First steps into creating a fluorescent dye-based biosensor for mAb aggregate detection.

A major challenge in the transition to continuous biomanufacturing is the lack of process analytical technology (PAT) tools which are able to collect real-time information on the process and elicit a response to facilitate control. One of the critical quality attributes (CQAs) of interest during monoclonal antibodies production is aggregate formation. The development of a real-time PAT tool to monitor aggregate formation is then crucial to have immediate feedback and process control. Miniaturized sensors placed after each unit operation can be a powerful solution to speed up an analytical measurement due to their characteristic short reaction time. In this work, a micromixer structure capable of mixing two streams is presented, to be employed in the detection of mAb aggregates using fluorescent dyes. Computational fluid dynamics (CFD) simulations were used to compare the mixing performance of a series of the proposed designs. A final design of a zigzag microchannel with 45° angle was reached and this structure was subsequently fabricated and experimentally validated with colour dyes and, later, with a FITC-IgG molecule. The designed zigzag micromixer presents a mixing index of around 90%, obtained in less than 30 seconds. Therefore, a micromixer channel capable of a fast and efficient mixing is hereby demonstrated, to be used as a real-time PAT tool for a fluorescence based detection of protein aggregation.

An unusual case of pacemaker endocarditis in a patient with antiphospholipid syndrome.

We report the case of a 50-year-old woman with systemic lupus erythematosus who had previously undergone pacemaker implantation. She developed recurrent pulmonary thromboembolism and was diagnosed with antiphospholipid syndrome. During investigation, pacemaker endocarditis was discovered, and the system was surgically explanted. Surprisingly, all microbiological studies, including culture of the extracted material and extensive serological analysis, were negative and she remained well with anticoagulation plus her usual immunosuppressant regimen. The data indicate that her pacemaker endocarditis could be an equivalent of the nonbacterial thrombotic endocarditis often described in native valves.

Pediatric Lisfranc Fracture-Dislocation: A Case Report.

Lisfranc injury is extremely rare in the pediatric population and little evidence exists to guide the treatment at this age. We present a clinical case of a rare Lisfranc fracture-dislocation at pediatric age. An 11-year-old male was admitted to the emergency department, in October 2020, after a motorcycle incident. He was diagnosed with a Lisfranc fracture-dislocation of the right foot: Myerson type B2. Fourteen days after the injury, he underwent surgical treatment with open reduction and internal fixation with 3.5 mm solid fully threaded screws. At 18 months postoperative, the patient was asymptomatic, didn't present any limitations, presented an American Orthopedic Foot and Ankle Score (AOFAS) midfoot score of 93%, and excellent results of the 12-Item Short Form Survey (SF-12) - PCS-12 (Physical Score): 52.52277 and MCS-12 (Mental Score): 62.12820. The foot maintained a good configuration without significant malalignment, however, a screw breakage occurred before the implant removal, and a premature physeal arrest developed on the base of the first metatarsal bone. Clinical and radiographic evaluation of Lisfranc injuries may be challenging in the pediatric population. Regarding the treatment, anatomical alignment is mandatory, and good or excellent outcomes have been achieved with anatomical reduction and internal fixation. We recommend early implant removal to avoid screw breakage and avoid the use of screws in the first metatarsal physis, due to the risk of premature physeal arrest.

Upregulation of tRNA-Ser-AGA-2-1 Promotes Malignant Behavior in Normal Bronchial Cells.

Serine tRNAs (tRNASer) are frequently overexpressed in tumors and associated with poor prognosis and increased risk of recurrence in breast cancer. Impairment of tRNA biogenesis and abundance also impacts proteome homeostasis, and activates protein quality control systems. Herein, we aimed at testing whether increasing tRNASer abundance could foster tumor establishment through activation of the UPR. In order to do so, firstly we confirmed that the expression of tRNA-Ser-AGA-2-1 [hereafter tRNASer(AGA)] was upregulated by 1.79-fold in Stage I NSCLC tumors when compared to normal adjacent tissue. To study the impact of tRNASer(AGA) in early stage tumorigenesis, we induced its upregulation in a non-tumoral bronchial cell line, BEAS-2B. Upregulation of this tRNA increased cellular proliferation and protein synthesis rate, driven by eIF2α dephosphorylation and ATF4 activation downstream of PERK signaling. Futhermore, tRNASer(AGA) enhanced transformation potential in vitro, and promoted the establishment of slow growing tumors with aggressive features in nude mice. Our work highlights the importance of studying tRNA deregulation on early stage tumorigenesis, as they may be potential malignancy and aggressiveness biomarkers.

Correction: Analysis of miRNA profiles identified miR-196a as a crucial mediator of aberrant PI3K/AKT signaling in lung cancer cells.

[This corrects the article DOI: 10.18632/oncotarget.13432.].

Epithelial-Mesenchymal Plasticity Induced by Discontinuous Exposure to TGFß1 Promotes Tumour Growth.

Transitions between epithelial and mesenchymal cellular states (EMT/MET) contribute to cancer progression. We hypothesize that EMT followed by MET promotes cell population heterogeneity, favouring tumour growth. We developed an EMT model by on and off exposure of epithelial EpH4 cells (E-cells) to TGFß1 that mimics phenotypic EMT (M-cells) and MET. We aimed at understanding whether phenotypic MET is accompanied by molecular and functional reversion back to epithelia by using RNA sequencing, immunofluorescence (IF), proliferation, wound healing, focus formation and mamosphere formation assays as well as cell xenografts in nude mice. Phenotypic reverted epithelial cells (RE-cells) obtained after MET induction presented epithelial morphologies and proliferation rates resembling E cells. However, the RE transcriptomic profile and IF staining of epithelial and mesenchymal markers revealed a uniquely heterogeneous mixture of cell subpopulations with a high self-renewal ability. RE cell heterogeneity was stably maintained for long periods after TGFß1 removal both in vitro and in large tumours derived from the nude mice. Overall, we show that phenotypic reverted epithelial cells (RE cells) do not return to the molecular and functional epithelial state and present mesenchymal features related to aggressiveness and cellular heterogeneity that favour tumour growth in vivo. This work strengthens epithelial cell reprogramming and cellular heterogeneity fostered by inflammatory cues as a tumour growth-promoting factor in vivo.

Oxidative-Signaling in Neural Stem Cell-Mediated Plasticity: Implications for Neurodegenerative Diseases.

The adult mammalian brain is capable of generating new neurons from existing neural stem cells (NSCs) in a process called adult neurogenesis. This process, which is critical for sustaining cognition and mental health in the mature brain, can be severely hampered with ageing and different neurological disorders. Recently, it is believed that the beneficial effects of NSCs in the injured brain relies not only on their potential to differentiate and integrate into the preexisting network, but also on their secreted molecules. In fact, further insight into adult NSC function is being gained, pointing to these cells as powerful endogenous "factories" that produce and secrete a large range of bioactive molecules with therapeutic properties. Beyond anti-inflammatory, neurogenic and neurotrophic effects, NSC-derived secretome has antioxidant proprieties that prevent mitochondrial dysfunction and rescue recipient cells from oxidative damage. This is particularly important in neurodegenerative contexts, where oxidative stress and mitochondrial dysfunction play a significant role. In this review, we discuss the current knowledge and the therapeutic opportunities of NSC secretome for neurodegenerative diseases with a particular focus on mitochondria and its oxidative state.

Transient symptomatic zinc deficiency in an exclusively breastfed infant.

A 3-month-old, full term female infant, adequate for gestational age, and exclusively breastfed, was admitted with a 10 day history of generalised scaling erythematous dermatitis, affecting the face (perinasal, nasolabial folds and periauricular), acral and intertriginous areas, with irritability and failure to thrive. Her mother had been treated with isoniazid since the third trimester because of family contact with tuberculosis. Based on a diagnosis of suspected impetiginised eczema, the infant was treated with flucloxacillin and prednisolone, and maternal isoniazid was suspended, with no improvement. Investigations found low serum zinc levels in the infant (33 µg/dL; normal range (NR) >60 µg/dL), normal plasma zinc levels in the mother (111.3 µg/dL; NR 68-120 µg/dL) and lower than the normal range of zinc levels in breast milk (270µg/L; NR 1000-2500 µg/L), suggesting acrodermatitis caused by zinc deficiency. Oral zinc supplementation (3 mg/kg/day) was started with a marked improvement in skin lesions, as well as good weight gain. At the age of 6 months, after food diversification, supplementation was suspended, without any recurrence of symptoms.

Epidemiology of bacteremia in a pediatric population - A 10-year study.

INTRODUCTION: With the widespread introduction of conjugate meningococcal and pneumococcal vaccines, the prevalence and etiology of invasive bacterial infections have changed. We aimed to review all cases of bacteremia in a level II pediatric department over a ten-year period in the post-pneumococcal conjugate vaccine era. METHODS: We reviewed all positive blood cultures (BC) obtained in our department between 2007 and 2016. Results were classified as contaminants, potential pathogens or confirmed pathogens, based on species, number of positive BC in the episode and the patients' medical history. Demographic and clinical data were collected for patients with identified pathogens. RESULTS: A total of 638 positive BC were identified (6.6% of total BC); 120 (1.2%) were considered to represent true bacteremia. The most frequently identified microorganism was Streptococcus pneumoniae (29.2%), with a decrease in the number of cases between 2008 and 2015. Staphylococcus aureus was the second most common organism (19.2%) being 21.7% of these methicillin-resistant. Escherichia coli was the most common isolate in children aged less than three months. CONCLUSION: We found a rate of true bacteremia in children similar to recent studies. Although Streptococcus pneumoniae remains the most common microorganism, its prevalence may be declining. Monitoring microbiological data in children has implications in practice, particularly in local antibiotic prescription.