Publications

Objective: Most endodontic diseases are bacterium-mediated inflammatory or necrotic process induced by contaminated dental pulp. Although great advances are being performed to obtain more efficient antibacterial strategies for persistent infections, most studies lack of representative models to test their antibacterial effects and their outcomes cannot be promptly translated to clinical practice. Therefore, this study aimed to refine an ex vivo endodontic biofilm model combining human tooth, computer guided design and 3D printing to obtain a more reproducible and predictable model. Methods: Monoradicular teeth were cut using three different methods: hand-held (HCC), mechanical precision (MPC) and computer aid guided cutting (CGC). Then, blocks were reassembled. The different model preparations were assessed in terms of dimensional tolerance, surface analysis, liquid tightness and Enterococcus faecalis biofilm development for 21 days, which was studied by metabolic assays and confocal microscopy. Then, the proposed model was validated using different commercial disinfecting treatments. Results: CGC exhibited significantly lower deviation and surface without defects compared to HHC and MPC, leading to superior liquid tightness. Similarly, mature biofilms with high metabolic activity and vitality were observed in all conditions, CGC showing the lowest variation. Regarding the model validation, all antibacterial treatments resulted in the complete eradication of bacteria in the standard 2D model, whereas commercial treatments exhibited varying levels of efficacy in the proposed ex vivo model, from moderately reduction of metabolic activity to complete elimination of biofilm. Conclusions: The novel guided approach represents a more reliable, standardized, and reproducible model for the evaluation of endodontic disinfecting therapies. Clinical Significance: During antibacterial treatment development, challenging 3D models using teeth substrates to test antibacterial treatments novel guided approach represents a more reliable, standardized, and reproducible model for the evaluation of endodontic disinfecting therapies.

JTD Keywords: 3d printin, Bacteria, Biofilm, Computer-aided manufacturing, Dental model, Dentin, Efficacy, Endodontics, Enterococcus faecalis, Enterococcus-faecalis, Irrigation, Protocols, Removal, Resistance, Susceptibility, Syste

Mycobacterium brumae is a rapid-growing, non-pathogenic Mycobacterium species, originally isolated from environmental and human samples in Barcelona, Spain. Mycobacterium brumae is not pathogenic and it's in vitro phenotype and immunogenic properties have been well characterized. However, the knowledge of its underlying genetic composition is still incomplete. In this study, we first describe the 4 Mb genome of the M. brumae type strain ATCC 51384T assembling PacBio reads, and second, we assess the low intraspecies variability by comparing the type strain with Illumina reads from three additional strains. Mycobacterium brumae genome is composed of a circular chromosome with a high GC content of 69.2% and containing 3,791 CDSs, 97 pseudogenes, one prophage and no CRISPR loci. Mycobacterium brumae has shown no pathogenic potential in in vivo experiments, and our genomic analysis confirms its phylogenetic position with other non-pathogenic and rapid growing mycobacteria. Accordingly, we determined the absence of virulence-related genes, such as ESX-1 locus and most PE/PPE genes, among others. Although the immunogenic potential of M. brumae was proved to be as high as Mycobacterium bovis BCG, the only mycobacteria licensed to treat cancer, the genomic content of M. tuberculosis T cell and B cell antigens in M. brumae genome is considerably lower than those antigens present in M. bovis BCG genome. Overall, this work provides relevant genomic data on one of the species of the mycobacterial genus with high therapeutic potential.Copyright © 2023 Renau-Mínguez, Herrero-Abadía, Ruiz-Rodriguez, Sentandreu, Torrents, Chiner-Oms, Torres-Puente, Comas, Julián and Coscolla.

JTD Keywords: antimicrobial susceptibility, bcg, identification, immunogenic, non-pathogenic, nontuberculous mycobacteria, resistance mechanisms, strain, therapeutic, Diversity, Immunogenic, Non-pathogenic, Nontuberculous mycobacteria, Therapeutic

Several studies have demonstrated the different characteristics of tau seeding and spreading following intracerebral inoculation in murine models of tau-enriched fractions of brain homogenates from AD and other tauopathies. The present study is centered on the importance of host tau in tau seeding and the molecular changes associated with the transformation of host tau into abnormal tau. The brains of three adult murine genotypes expressing different forms of tau—WT (murine 4Rtau), hTau (homozygous transgenic mice knock-out for murine tau protein and heterozygous expressing human forms of 3Rtau and 4Rtau proteins), and mtWT (homozygous transgenic mice knock-out for murine tau protein)—were analyzed following unilateral hippocampal inoculation of sarkosyl-insoluble tau fractions from the same AD and control cases. The present study reveals that (a) host tau is mandatory for tau seeding and spreading following tau inoculation from sarkosyl-insoluble fractions obtained from AD brains; (b) tau seeding does not occur following intracerebral inoculation of sarkosyl-insoluble fractions from controls; (c) tau seeding and spreading are characterized by variable genotype-dependent tau phosphorylation and tau nitration, MAP2 phosphorylation, and variable activation of kinases that co-localize with abnormal tau deposits; (d) transformation of host tau into abnormal tau is an active process associated with the activation of specific kinases; (e) tau seeding is accompanied by modifications in tau splicing, resulting in the expression of new 3Rtau and 4Rtau isoforms, thus indicating that inoculated tau seeds have the capacity to model exon 10 splicing of the host mapt or MAPT with a genotype-dependent pattern; (e) selective regional and cellular vulnerabilities, and different molecular compositions of the deposits, are dependent on the host tau of mice injected with identical AD tau inocula.

JTD Keywords: 3rtau and 4rtau, alzheimer's disease, alzheimer’s disease, brains, granulovacuolar degeneration, host tau, htau, intranuclear distribution, messenger-rna, pathological tau, propagation, protein-kinases, seeding and spreading, tauopathies, transmission, 3rtau and 4rtau, Alzheimer disease, Alzheimers-disease, Alzheimer’s disease, Animals, Biomarkers, Brain, Disease models, animal, Disease susceptibility, Fluorescent antibody technique, Genotype, Hippocampus, Host tau, Htau, Humans, Immunohistochemistry, Mice, Mice, knockout, Mice, transgenic, Mutation, Neurons, Seeding and spreading, Tau proteins, Tauopathies

The hallmark of Lafora disease, a fatal neurodegenerative disorder, is the accumulation of intracellular glycogen aggregates called Lafora bodies. Until recently, it was widely believed that brain Lafora bodies were present exclusively in neurons and thus that Lafora disease pathology derived from their accumulation in this cell population. However, recent evidence indicates that Lafora bodies are also present in astrocytes. To define the role of astrocytic Lafora bodies in Lafora disease pathology, we deleted glycogen synthase specifically from astrocytes in a mouse model of the disease (malin(KO)). Strikingly, blocking glycogen synthesis in astrocytes-thus impeding Lafora bodies accumulation in this cell type-prevented the increase in neurodegeneration markers, autophagy impairment, and metabolic changes characteristic of the malin(KO) model. Conversely, mice that over-accumulate glycogen in astrocytes showed an increase in these markers. These results unveil the deleterious consequences of the deregulation of glycogen metabolism in astrocytes and change the perspective that Lafora disease is caused solely by alterations in neurons.

JTD Keywords: Bodies, Deficient mice, Epilepsy, Glycogen, Impairment, Lafora disease, Malin, Modulation, Mouse model, Neurodegeneration, Neuroinflammation, Neurons, Progressive myoclonus epilepsy, Seizure susceptibility, Synthase