Dysbiotic oral microbiota contributes to alveolar bone loss associated with obesity in mice

Periodontal diseases (PD) are inflammatory conditions that affect the teeth supporting tissues. Increased body fat tissues may contribute to activation of the systemic inflammatory response, leading to comorbidities. Some studies have shown that individuals with obesity present higher incidence of PD than eutrophics. Objective: To investigate the impact of obesity on periodontal tissues and oral microbiota in mice. Methodology: Two obesity mice models were performed, one using 12 weeks of the dietary protocol with a high-fat (HF) diet in C57BL/6 mice and the other using leptin receptor-deficient mice (db/db-/-), which became spontaneously obese. After euthanasia, a DNA-DNA hybridization technique was employed to evaluate the microbiota composition and topical application of chlorhexidine (CHX), an antiseptic, was used to investigate the impact of the oral microbiota on the alveolar bone regarding obesity. Results: Increased adipose tissue may induce alveolar bone loss, neutrophil recruitment, and changes in the oral biofilm, similar to that observed in an experimental model of PD. Topical application of CHX impaired bone changes. Conclusion: Obesity may induce changes in the oral microbiota and neutrophil recruitment, which are associated with alveolar bone loss

Síntese e caracterização estrutural e biológica de vidros bioativos com capacidade de liberação controlada de íons metálicos Mn e Co com potencial efeito terapêutico osteogênico e angiogênico para aplicações na engenharia de tecidos

Exportado OPUSMade available in DSpace on 2019-08-14T21:15:00Z (GMT). No. of bitstreams: 1 tese_doutorado___vers_o_final.pdf: 7518844 bytes, checksum: c9bf3e7932abe94be476b3e7eaf4cf15 (MD5) Previous issue date: 10Vidros bioativos são materiais de destaque na engenharia de tecidos devido à sua alta bioatividade e biocompatibilidade. Diferentes composições de vidros bioativos podem ser obtidas pelo processo sol-gel, e a sua estrutura permite a incorporação de várias concentrações de diferentes íons com atividades fisiológicas e propriedades terapêuticas, que são liberados durante o processo de dissolução do material, aprimorando o seu desempenho. Dentre diferentes íons com propriedades terapêuticas estão o manganês, que tem demonstrado aprimorar a adesão celular, crescimento e proliferação de osteoblastos, e também o cobalto, conhecido por ser um poderoso agente angiogênico. Nesse contexto, este trabalho relata o desenvolvimento de novas composições de vidros bioativos derivados do processo sol-gel contendo manganês ou cobalto em sua estrutura, como potenciais íons metálicos terapêuticos. A influência da incorporação de diferentes concentrações desses íons na estrutura e propriedades dos vidros bioativos foi avaliada. Micropartículas de vidro bioativo contendo Mn e Co com capacidade de liberação controlada de íons em meio fisiológico foram obtidos. Análises estruturais confirmaram a presença de Mn2+ na estrutura dos vidros bioativos. Espécies Co2+ foram majoritariamente observadas nos vidros contendo esse íon, embora a utilização de diferentes precursores tenha demonstrado afetar a estrutura desses materiais, observando-se a presença de espécies Co3+ quando o cloreto de cobalto foi utilizado como precursor. A viabilidade de células expostas a diferentes concentrações do produto iônico dos materiais foi confirmada. Vidros bioativos contendo Mn demonstraram capacidade de estimular todos os estágios de diferenciação de células-tronco mesenquimais derivadas da medula óssea humana e subsequente mineralização, confirmando seu papel no aprimoramento da regeneração óssea. Já os estudos morfológicos e histológicos realizados após implante de vidros bioativos contendo Co em ratos demonstraram que não houve indução de respostas adversas, e a presença de infiltrado inflamatório e vasos neoformados foram indicativos de um alto nível de angiogênese no material. A incorporação de Mn e Co em vidros bioativos se mostrou como uma potencial estratégia para aprimoramento do seu potencial para a engenharia de tecidos.Bioactive glasses are outstanding materials in tissue engineering due to their high bioactivity and biocompatibility. Different bioactive glass compositions can be obtained by the sol-gel process, and their structure allows the incorporation of various concentrations of different ions with physiological activities and therapeutic properties. Those ions are released during the dissolution process of the material, improving its performance. Among the different ions with therapeutical properties, manganese has been shown to enhance cell adhesion, growth and proliferation of osteoblasts, while cobalt is a known angiogenic agent. In this context, this work reports the development of new bioactive glass compositions derived from the sol-gel process, containing manganese or cobalt in their structure, as potential therapeutic metallic ions. The influence of the incorporation of different concentrations of these ions on the structure and properties of the bioactive glasses was evaluated. Bioactive glass microparticles containing Mn and Co with controlled ion release capability in physiological medium were obtained. Structural evaluation confirmed the presence of Mn2+ in the structure of bioactive glasses, while Co2+ were mostly observed in the glasses containing this ion, although the use of different precursors has been shown to affect the structure of these materials, with the presence of Co3+ species when cobalt chloride was used as precursor. The viability of cells exposed to different concentrations of the bioactive glasses ionic product was confirmed. Bioactive glasses containing Mn demonstrated ability to stimulate all stages of differentiation of mesenchymal stem cells derived from human bone marrow and subsequent mineralization, confirming their role in enhancing bone regeneration. The morphological and histological studies performed after the implantation of bioactive glasses containing Co in rats demonstrated that there was no induction of adverse responses, and the presence of inflammatory infiltrate and neoformed vessels are indicative of a high level of angiogenesis in the material. The incorporation of Mn and Co in bioactive glasses has proved to be a potential strategy to improve its potential for tissue engineering

Carbon nanostructures-modified expanded vermiculites produced by chemical vapor deposition from ethanol.

In this work, chemical vapor deposition using ethanol and FeMo catalysts at 600, 700, 800 and 900 °C was used to modify the surface of expanded vermiculite (EV). Scanning electron microscopy, Raman spectroscopy, X-ray diffraction, Mössbauer spectra, N2-BET surface areas, and carbon elemental analyses suggested that the FeMo catalyst promoted 2–3% growth of carbon in different forms, mainly nanofibers, on the EV surface. The amount of 2–3% carbon produced by ethanol/CVD process on EV produced a 500% increase in the absorption of soybean, diesel and engine oil, with a concomitant decrease on water absorption. These results were discussed in terms of a hydrophobization of the EV surface by the carbon structures and a “sponge-like” effect due to the entangled nanofibers structure, as it was observed by microscopy, and an increase of N2-BET surface area from 3 m2 g−1 for EV up to 21 m2 g–1 for the ethanol CVD-treated EV

Bone strength is reduced in a neonatal androgenized rat model

Background: Whether polycystic ovary syndrome (PCOS) affects bone health during a woman's lifespan remains controversial. An androgenized rodent model replicated many metabolic and reproductive features of women with PCOS, and we aimed to use it to investigate the impact of androgens on microarchitecture (by micro-CT), bone mechanical strength, bone formation and resorption markers in rats with intact ovaries (SHAM) who underwent oophorectomy. Methods: Wistar rats (Rattus norvegicus albinus) were employed for the experiments in this study. The protocol of androgenization consisted of the application of 1.25 mg s.c. testosterone propionate beteween days 2–5 of life, while the controls received the same amount of corn oil s.c. as previously established. Androgenized SHAM rats exhibited chronic anovulation identified by vaginal cytology and a reduction in the proportion of corpus luteum in the ovary in comparison to control SHAM rats. The realization of the ovariectomy or SHAM procedure occurred on Day 100 of life. All groups (n = 8) were followed-up for 180 days to address the study endpoints. Results: Micro-CT from androgenized female rats (SHAM) showed a divergence between the trabecular and cortical bone profiles. Compared to SHAM controls, these rats had an increase in trabecular bone mass with a diminution in bone resorption C-terminal telopeptide of type 1 collagen (CTX) (p < 0.05), a concomitant decrease in cortical area and thickness in the femur, and a reduction in the strength of the femur on the mechanical test (p < 0.01). Conclusions: Our results suggest that a reduction in the cortical thickness and cortical area observed in PCOS model rats was associated with a reduced strength of the femur, despite increased trabecular formation. Ovariectomy in the androgenized OVX group limited the progression rate of cortical bone loss, resulting in bone resistance and cortical thickness comparable to those observed in the control OVX group