Browsing by Author "Oliveira, Ketlyn"
Now showing 1 - 10 of 13
Results Per Page
Sort Options
- Análise do efeito biológico de extratos de folhas de Carica papaya na viabilidade e na proliferação de células K562Publication . Canteiro, Beatriz; Mendes, Maria; Delgadinho, Mariana; Oliveira, Ketlyn; Ginete, Catarina; Gomes, Mário; Ribeiro, Edna; Brito, Miguel; Gomes, Anita Q.Introdução – A anemia falciforme é uma doença monogénica causada por mutações no gene da β-globina que afeta a estrutura da hemoglobina, sendo associada a diversas complicações clínicas com elevadas taxas de morbilidade e mortalidade. A reativação farmacológica da hemoglobina fetal (HbF) por compostos como a hidroxiureia (HU) é um dos tratamentos atualmente disponíveis; contudo, o seu perfil de segurança e o elevado custo em países subdesenvolvidos limitam a sua utilização. Nesse contexto é essencial estudar novos compostos indutores da HbF com baixa citotoxicidade e que possam estar amplamente disponíveis, como é o caso de extratos de folhas da Carica papaya (CP), uma planta medicinal com propriedades antioxidantes e anti-inflamatórias. Objetivos – Este estudo pretende avaliar o efeito do extrato metanólico das folhas de CP (EMFCP) em parâmetros biológicos como a proliferação e a viabilidade celular em células K562. Método – As células K562 foram expostas durante 72h ao EMFCP a 500 µg/mL e durante 24 horas ao EMFCP (0,5; 50; 100 µg/mL) e à HU (25 μg/mL). A proliferação e viabilidade celular foram analisadas através da quantificação celular pelo método de exclusão do azul de tripano. Resultados – Os resultados demonstram que a proliferação e a viabilidade celular foram afetadas pelo EMFCP apenas na concentração de 500 µg/mL, não se tendo verificado alteração nestes parâmetros nas restantes concentrações utilizadas. Conclusão – Os resultados mostraram que os EMFCP não são citotóxicos quando incubados em células K562 em concentrações inferiores ou iguais a 100 μg/mL, permitindo assim explorar este composto na avaliação do seu potencial terapêutico no contexto da anemia falciforme.
- Atividade antagonista do leite fermentado por kefir contra Staphylococcus aureus resistentes à meticilina (MRSA)Publication . Bento, Alice; Oliveira, Ketlyn; Vasques, Margarida; Ribeiro, EdnaA crescente resistência microbiana aos antibióticos é considerada uma das maiores ameaças à saúde pública a nível mundial e promove uma necessidade urgente de desenvolvimento de novas opções terapêuticas. O probiótico kefir tem vindo a ser apontado como um potencial agente antimicrobiano contra bactérias com capacidade de aquisição de multirresistências como Staphylococcus aureus. S. aureus resistente à meticilina (MRSA) é definido como prioridade de saúde pública, associado a infeções da comunidade e nosocomiais com elevadas taxas de mortalidade. Este estudo tem como objetivo avaliar a capacidade antagonista do probiótico kefir contra MRSA. Neste estudo foram utilizadas três variantes biológicas de grãos de kefir para testar a suscetibilidade de MRSA segundo os métodos de spot-on-lawn para avaliação de inibição de crescimento e de diluição para contagem estimada de UFC/mL. O leite fermentado por kefir após 24 horas de fermentação foi utilizado de forma integral, isto é, sem extração dos seus componentes. A análise de resultados obtidos demonstrou que a capacidade de inibição do MRSA pelo leite fermentado por kefir é dependente da dose e das variantes biológicas dos grãos. Estes resultados apontam o kefir como um potencial agente natural possível de ser utilizado como adjuvante para fins terapêuticos ou de descolonização contra o MRSA.
- DNA methylation in diabetic macular edema: first reportPublication . Camacho, Pedro; Pereira, Bruno; Ribeiro, Edna; Varandas, T.; Henriques, J.; Nascimento, J.; Dutra-Medeiros, M.; Ribeiro, C.; Delgadinho, Mariana; Oliveira, Ketlyn; Silva, Carina; Brito, MiguelEnvelhecimento humano e estilos de vida tem contribuído para aumento da DM. Edema macular diabético (EMD), uma das manifestações oculares da RD, é a principal causa de perda de visão em pessoas diabéticas. 30-40% casos EMD não respondem da melhor forma aos AVEGF (loading phase). Resistência pode persistir após 12 meses tratamento (+/50%). Objetivo do estudo: Desenvolver uma caracterização multimodal não invasiva (SD OCT e OCT A) combinada com a avaliação da metilação de DNA de forma a pode esclarecer alguns mecanismos importantes da doença mas também para novas abordagens terapêuticas que contribuem para a medicina de precisão.
- DNA methyltransferase expression (DNMT1, DNMT3a and DNMT3b) as a potential biomarker for anti-VEGF diabetic macular edema responsePublication . Camacho, Pedro; Ribeiro, Edna; Pereira, Bruno; Varandas, Teresa; Nascimento, João; Henriques, José; Dutra-Medeiros, Marco; Delgadinho, Mariana; Oliveira, Ketlyn; Silva, Carina; Brito, MiguelPurpose: DNA methylation is involved in Diabetic Retinopathy progression showing a metabolic memory mechanism. However, the association of DNA methyltransferase with diabetic macular edema is still unknown. We aimed to describe the differences in DNA methyltransferase gene expression in patients with different diabetic macular edema responses. Methods: A total of 27 diabetic patients, aged 59-90 years, were prospectively enrolled in this cross-sectional study. The participants were classified into the control group (CG, n = 11), diabetic macular edema responders (rDME, n = 9), and non-responder diabetic macular edema (nrDME, n = 7) after anti-vascular endothelial growth factor (anti-VEGF) treatment. Only cases with a complete ophthalmological examination, digital 133° color fundus, and SD-OCT assessments were used. After RNA extraction and first-strand cDNA synthesis, quantitative real-time PCR was performed with specific primers on the CFX Connect™ Real-Time PCR Detection System to assess differential transcriptional expression patterns. Results: The DNMT1 gene showed a positive correlation (r = 0.617; p = 0.043) with Best Corrected Visual Acuity (BCVA) in CG, a positive correlation (r = 0.917; p = 0.010) with HbA1c in nrDME and a negative correlation (r = -0.659; p = 0.049) with GCL-IPL thickness in rDME. DNMT3A gene showed a positive correlation (r = -0.890; p = 0.001) with Sub-foveal Choroidal thickness in rDME whereas DNMT3b gene showed a negative correlation (r = -0.815; p = 0.007) with HbA1c and RNFL (r = -0.664; p = 0.026) in CG. Conclusions: Patients with similar metabolic profile risk factors showed associated DNA methyltransferase transcriptional expression patterns differences fitting with the anti-VEGF diabetic macular edema response. Further studies are needed to clarify if these results (1) reflect disease evolution, (2) translate the therapeutic impact, (3) or can help to predict the therapeutic resistance profile.
- Effects of Carica papaya leaf extracts in transcriptional regulation of fetal hemoglobinPublication . Mendes, M.; Canteiro, Beatriz; Delgadinho, Mariana; Oliveira, Ketlyn; Ginete, Catarina; Gomes, Mário; Ribeiro, Edna; Brito, Miguel; Gomes, Anita Q.Purpose: Sickle cell disease (SCD) is one of the most common human genetic disorders, which is caused by a single point mutation (Glu6Val) on the HBB gene. Currently, one of the treatments for this global health problem involves the induction of fetal hemoglobin (HbF). There are some drugs on the market that pharmacologically induce HbF, namely Hydroxyurea (HU), however, their safety concerns and the expensive cost in low- and middle-income countries limit their use. In this context, it is essential to study novel fetal hemoglobin-inducing compounds that have fewer adverse effects and are widely available, such as natural compounds. Therefore, the main aim of this work was to evaluate the effects of Carica Papaya methanolic leaf extracts (CPMLE) in HbF reactivation.
- Effects of methanolic and aqueous Carica Papaya leaf extracts in transcriptional and miRNA-mediated regulation of fetal hemoglobinPublication . Jacques, Filipa; Canteiro, Beatriz; Mendes, Maria; Delgadinho, Mariana; Oliveira, Ketlyn; Ginete, Catarina; Gomes, Mário; Ribeiro, Edna; Brito, Miguel; Gomes, Anita Q.Sickle cell disease (SCD) is a genetic blood disorder caused by mutations in β-globin gene that affect the shape and transport of red blood cells in blood vessels, leading to various clinical complications. The pharmacological reactivation of Fetal Hemoglobin (HbF) through compounds such as Hydroxyurea (HU), is one of the available treatments, however, their safety concerns and expensive cost in low- and middle-income countries limit their use. In this context, it is essential to study novel HbF-inducing compounds that have scarcer adverse effects and can be widely available, such as Carica papaya extracts, a medicinal plant with anti-oxidant and anti-inflammatory properties. Therefore, the main aim of this work is to evaluate the effects of Carica Papaya leaf extracts (CPLE) in HbF reactivation. More specifically, we started by evaluating the effect of a methanolic CPLE extract in K562 cells (human immortalized myeloid leukemia cell line) at the proliferation rate and viability of the K562 cell line, compared to HU exposure. Subsequently, we analyzed the expression levels of HBG1 and HBG2 genes and that of their transcriptional and miRNA-mediated regulators. To achieve these goals, the K562 cell line was first exposed for 72 hours to CPMLE at 500 μg/mL and for 24 hours to EMFCP (0.5; 50, and 100 μg/mL) and to HU (25 μg/mL). After exposure to natural compounds, the effects of gene expression were quantified from total RNA using RT-qPCR. The results have indicated that cell proliferation and viability were affected by CPMLE only at the concentration of 500 μg/ml, with no effects being observed at the lower concentrations analyzed. Upon analysis of the expression levels of globins (HBA, HBB, HBG1, and HBG2), HbF regulatory genes (MYB, KLF1, BCL11A, and BGLT3), and miRNAs involved in the regulation of HbF we could observe more significant differences for the lower concentrations of extracts used, namely at the concentration of 0.5 μg/ml. As such we have decided to titrate down the concentration of methanolic leaf extracts used and test the exposure to aqueous leaf extracts which possess different biological compounds that might lead to a differential regulation of the genes under analysis. Our preliminary results have revealed that at the concentrations of 0,05 ug/ml; 0,5 ug/ml and 5 ug/ml the cell viability and proliferation rates were not affected either for methanolic or aqueous extracts. We are currently analyzing the expression levels of target and regulatory genes to determine the effect of both types of leaf extracts on regulators of HbF expression.
- Effects of Quercetin in transcriptional and post-transcriptional regulation of fetal hemoglobinPublication . Canteiro, Beatriz; Mendes, Maria; Jacques, Filipa; Delgadinho, Mariana; Oliveira, Ketlyn; Ginete, Catarina; Gomes, Mário; Ribeiro, Edna; Brito, Miguel; Gomes, Anita Q.Hemoglobinopathies are a group of inherited blood disorders that primarily affect red blood cells. The most common type is known as sickle cell anemia (SCA). It is characterized by mutations in the HBB gene, which encodes the β-subunit of human hemoglobin, giving rise to hemoglobin S (HbS). When deoxygenated, HbS polymerizes in the red blood cell, giving it a sickle shape and making it rigid and fragile. Fetal hemoglobin (HbF) is the major genetic modulator of the hematologic and clinical features of sickle cell disease, an effect mediated by its exclusion from the sickle hemoglobin polymer. Fetal hemoglobin genes are genetically regulated, and the level of HbF and its distribution among sickle erythrocytes is highly variable. Currently, therapies that induce HbF are promising, such as hydroxyurea (HU). However, due to high costs for underdeveloped countries and the adverse side effects, it is important to test alternative products and develop new compounds, such as Quercetin, a natural flavonoid present in plants that has antioxidant and anti-inflammatory properties.
- Effects of quercetin in transcriptional and post-transcriptional regulation of fetal hemoglobinPublication . Canteiro, Beatriz; Mendes, Maria; Jacques, Filipa; Delgadinho, Mariana; Oliveira, Ketlyn; Ginete, Catarina; Gomes, Mário; Ribeiro, Edna; Brito, Miguel; Gomes, Anita Q.Sickle Cell anemia (SCA) is a hereditary hemoglobinopathy with the formation of hemoglobin S, associated with severe health outcomes. Currently, induction of fetal hemoglobin (HbF) is one of the most promising therapeutic strategies. Here we aimed to assess the potential of the natural compound Quercetin, in transcriptional expression of globin and HbF regulatory/silencing genes. In this study, the K562 cell line was used as an SCA model. Cells were exposed to Quercetin at final concentrations of 0.2 and 20 µM, and Hydroxyurea (25 µg/mL) was used as a positive control. Cell viability and proliferation were assessed through trypan blue exclusion assay. Transcriptional expression was performed by RT-qPCR using specific primers. Significant differences were analyzed using a t-test. No cytotoxic effects were observed following exposure to Quercetin. The transcriptional analysis demonstrated that Quercetin affects mRNA levels of HbF regulatory/silencing genes with associated downregulation of BCL11A, MYB, KLF1, and HBB and upregulation of HBG and BGLT3, as well as alterations in the expression of miRNAs involved in HbF post-transcriptional regulation. Our results sustain Quercetin's potential as an HbF inducer with associated upregulation of HbF-activators and decreased expression of HbF-inhibitors. These data support the need for further studies in order to confirm the potential of this compound as a new therapeutic option for β -hemoglobinopathies in the future.
- Exposure to metals in the e-waste management industryPublication . Martins, Carla; Ribeiro, Edna; Oliveira, Ketlyn; Viegas, SusanaObjective: The burden of disease associated with occupational exposure is ~6%. The recent EU circular economy policy, where the recycling of e-waste is included, is expected to increase the waste management/recycling sector. The e-waste stream contains a broad range of chemicals namely metals. Human biomonitoring by measurement of specific biomarkers in body fluids is considered an effective method of exposure surveillance. The present study, framed in the HBM4EU project, aimed to assess the exposure to metals of the e-waste management workers in Portugal. Methods: A cross-sectional study was developed in two e-waste management companies in Portugal. Thirty workers, aged 31-62 years, collected spot urine samples at the beginning and in the end of the workweek, pre-shift, and end-shift, respectively. A control group of 12 participants, aged 38-56 years, with administrative tasks outside the companies was included. Urine samples were analyzed for the determination of cadmium (Cd), chromium (Cr), lead (Pb), and mercury (Hg). Results are expressed as µg metal/g creatinine. Results: Results revealed that, except for Cr, all analyzed samples presented levels of Cd, Pb, and Hg above the limit of quantification. Median levels in the end-shift samples were 0.21, 0.43, and 12.70 µg/g crea for Cd, Hg and Pb, respectively. Significant differences between the exposed group and the control group were found only for urinary Pb levels (p< 0.05). Conclusions: This study increased the knowledge and understanding of how work practices translate into exposure. These data contribute to the implementation of risk management measures intending to decrease the burden associated with exposure to chemicals in this occupational setting.
- MRSA colonization in workers from different occupational environments: a one health approach perspectivePublication . Oliveira, Ketlyn; Viegas, Carla; Ribeiro, EdnaStaphylococcus aureus and particularly methicillin-resistant S. aureus (MRSA) infections are currently associated with extremely high morbidity and mortality rates worldwide. The global escalation in the development of antibiotic-resistant human pathogens and S. aureus's ability in developing new clones with the capacity to invade community settings leads to an urgent need to develop accurate and efficient assessments of S. aureus colonization in occupational settings, particularly those with increased risk of human and animal colonization and food contamination. Here we present cross-sectional studies with the aim to assemble crucial information regarding MRSA prevalence in workers from five different Portuguese occupational environments (bakeries, swineries (humans and animals), ambulance crews, veterinary clinics, and healthcare facilities). Our data demonstrated a high prevalence of S. aureus asymptomatic carriers among bakery workers (40%; 75% MSSA and 25% MRSA), swinery workers (54%; 8% MSSA and 46% MRSA), firefighters (48.5%; 24% MSSA and 21% MRSA) and healthcare workers (Study 1: 42.2%; 18.4% MSSA and 23.7% MRSA, Study 2: 43.3% MRSA). S. aureus prevalence in veterinary staff was 7.1% (MSSA), lower than the results obtained in control groups (33.3% S. aureus; MRSA 4% to 10%). The present study sustains the urge to develop an accurate and efficient assessment of S. aureus human and animal colonization, particularly in high-risk occupational settings, with proper guidelines and validated procedures in order to avoid potential hazardous health outcomes associated with bioaerosol exposure and associated infectious diseases.