https://repositorio.uchile.cl/handle/2250/117713 Artículos de revistas Tue, 05 May 2026 18:34:17 GMT 2026-05-05T18:34:17Z https://repositorio.uchile.cl/handle/2250/195876 First identification of reinfection by a genetically different variant of SARS-CoV-2 in a homeless person from the Metropolitan area of Santiago, Chile Acuña Castillo, Claudio; Vidal, Mabel; Inostroza Molina, Ailen; Vallejos Vidal, Eva; Luraschi, Roberto; Figueroa, Maximiliano; Barrera Avalos, Carlos; Vera, Rodrigo; Vargas, Sergio; Valdés, Daniel; Maisey, Kevin; Imarai, Mónica; Leiva Salcedo, Elías; Escobar Álvarez, Alejandro Felipe; Reyes Cerpa, Sebastián; Gaete Silva, Alexis Ignacio; Palma Vejares, Ricardo Fernando; Travisany Flores, Dante Felipe; Rojo, Leonel E.; Reyes López, Felipe E.; Sandino, Ana María The identification and tracking of SARS-CoV-2 infected patients in the general population are essential components of the global strategy to limit the COVID-19 viral spread, specifically for maintaining traceability and suppressing the resurgence of local outbreaks. Public health programs that include continuous RT-qPCR testing for COVID-19 in the general population, viral sequencing, and genomic surveillance for highly contagious forms of the virus have allowed for the identification of SARS-CoV-2 infections and reinfections. This work identified SARS-CoV-2 reinfection in a homeless person, which occurred 58 days after the first COVID-19 diagnosis. Genomic sequencing identified a different Nextstrain classification clade (20A and 20B) and PANGO lineage, with a divergence of 4 single nucleotide variants (SNVs) in S and ORF1ab genes, suggesting reinfection by different viral variants. This study is the first from the great metropolitan area of Santiago, Chile, one of the top ten countries in the world to live during the COVID-19 pandemic. We support the importance of performing intensive genomic surveillance programs in the whole population and high-risk groups, such as homeless people, nearly 20 thousand people in Chile, and have limited access to health care services and poor viral traceability. Sat, 01 Jan 2022 00:00:00 GMT https://repositorio.uchile.cl/handle/2250/195876 2022-01-01T00:00:00Z https://repositorio.uchile.cl/handle/2250/194933 Crosstalk between body microbiota and the regulation of immunity Rojas Pérez, Carolina Isabel; Gálvez Jirón, Felipe; Solminihac, Javiera de; Padilla, Cristina; Cárcamo, Ignacio; Villalón, Natalia; Kurte, Mónica; Pino Lagos, Karina The microbiome corresponds to the genetic component of microorganisms (archaea, bacteria, phages, viruses, fungi, and protozoa) that coexist with an individual. During the last two decades, research on this topic has become massive demonstrating that in both homeostasis and disease, the microbiome plays an important role, and in some cases, a decisive one. To date, microbiota have been identified at different body locations, such as the eyes, lung, gastrointestinal and genitourinary tracts, and skin, and technological advances have permitted the taxonomic characterization of resident species and their metabolites, in addition to the cellular and molecular components of the host that maintain a crosstalk with local microorganisms. Here, we summarize recent studies regarding microbiota residing in different zones of the body and their relationship with the immune system. We emphasize the immune components underlying pathological conditions and how they interact with local (and distant) microbiota. Sat, 01 Jan 2022 00:00:00 GMT https://repositorio.uchile.cl/handle/2250/194933 2022-01-01T00:00:00Z https://repositorio.uchile.cl/handle/2250/194815 Autophagy in aging-related oral diseases Peña Oyarzún, Daniel; San Martin, Carla; Hernández Cáceres, María Paz; Lavandero González, Sergio Alejandro; Morselli, Eugenia; Budini Budini, Mauricio Fernando; Burgos, Patricia V.; Criollo Céspedes, Alfredo Guillermo Autophagy is an intracellular degradation mechanism that allows recycling of organelles and macromolecules. Autophagic function increases metabolite availability modulating metabolic pathways, differentiation and cell survival. The oral environment is composed of several structures, including mineralized and soft tissues, which are formed by complex interactions between epithelial and mesenchymal cells. With aging, increased prevalence of oral diseases such as periodontitis, oral cancer and periapical lesions are observed in humans. These aging-related oral diseases are chronic conditions that alter the epithelial-mesenchymal homeostasis, disrupting the oral tissue architecture affecting the quality of life of the patients. Given that autophagy levels are reduced with age, the purpose of this review is to discuss the link between autophagy and age-related oral diseases. Sat, 01 Jan 2022 00:00:00 GMT https://repositorio.uchile.cl/handle/2250/194815 2022-01-01T00:00:00Z https://repositorio.uchile.cl/handle/2250/194809 Exploring the expression of pro-inflammatory and hypoxia-related microRNA-20a, MicroRNA-30e, and microRNA-93 in periodontitis and gingival mesenchymal stem cells under hypoxia Chaparro, Alejandra; Lozano, Mauricio; Gaedechens, Dominique; López, Carolina; Albers, Daniela; Hernández Ríos, Emma Marcela; Pascual, Andrés; Nart, José; Irarrazabal, Carlos E. Hypoxia associated with inflammation are common hallmarks observed in several diseases, and it plays a major role in the expression of non-coding RNAs, including microRNAs (miRNAs). In addition, the miRNA target genes for hypoxia-inducible factor-1 alpha (HIF-1 alpha) and nuclear factor of activated T cells-5 (NFAT5) modulate the adaptation to hypoxia. The objective of the present study was to explore hypoxia-related miRNA target genes for HIF-1 alpha and NFAT5, as well as miRNA-20a, miRNA-30e, and miRNA-93 expression in periodontitis versus healthy gingival tissues and gingival mesenchymal stem cells (GMSCs) cultured under hypoxic conditions. Thus, a case-control study was conducted, including healthy and periodontitis subjects. Clinical data and gingival tissue biopsies were collected to analyze the expression of miRNA-20a, miRNA-30e, miRNA-93, HIF-1 alpha, and NFAT5 by qRT-PCR. Subsequently, GMSCs were isolated and cultured under hypoxic conditions (1% O-2) to explore the expression of the HIF-1 alpha, NFAT5, and miRNAs. The results showed a significant upregulation of miRNA-20a (p = 0.028), miRNA-30e (p = 0.035), and miRNA-93 (p = 0.026) in periodontitis tissues compared to healthy gingival biopsies. NFAT5 mRNA was downregulated in periodontitis tissues (p = 0.037), but HIF-1 alpha was not affected (p = 0.60). Interestingly, hypoxic GMSCs upregulated the expression of miRNA-20a and HIF-1 alpha, but they downregulated miRNA-93e. In addition, NFAT5 mRNA expression was not affected in hypoxic GMSCs. In conclusion, in periodontitis patients, the expression of miRNA-20a, miRNA-30e, and miRNA-93 increased, but a decreased expression of NFAT5 mRNA was detected. In addition, GMSCs under hypoxic conditions upregulate the HIF-1 alpha and increase miRNA-20a (p = 0.049) expression. This study explores the role of inflammatory and hypoxia-related miRNAs and their target genes in periodontitis and GMSCs. It is crucial to determine the potential therapeutic target of these miRNAs and hypoxia during the periodontal immune-inflammatory response, which should be analyzed in greater depth in future studies. Sat, 01 Jan 2022 00:00:00 GMT https://repositorio.uchile.cl/handle/2250/194809 2022-01-01T00:00:00Z