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- Occupational exposure to aflatoxin (AFB1) in poultry productionPublication . Viegas, Susana; Veiga, Luísa; Malta-Vacas, Joana; Sabino, Raquel; Figueiredo, Paula; Almeida, Ana; Viegas, Carla; Carolino, ElisabeteAflatoxin B1 (AFB1) has been recognized to produce cancer in human liver. In addition, epidemiological and laboratory studies demonstrated that the respiratory system was a target for AFB1. Exposure occurs predominantly through the food chain, but inhalation represents an additional route of exposure. The present study aimed to examine AFB1 exposure among poultry workers in Portugal. Blood samples were collected from a total of 31 poultry workers from six poultry farms. In addition, a control group (n = 30) was included comprised of workers who undertook administrative tasks. Measurement of AFB1 in serum was performed by enzyme-linked immunosorbent assay (ELISA). For examining fungi contamination, air samples were collected through an impaction method. Air sampling was obtained in pavilion interior and outside the premises, since this was the place regarded as the reference location. Using molecular methods, toxicogenic strains (aflatoxin-producing) were investigated within the group of species belonging to Aspergillus flavus complex. Eighteen poultry workers (59%) had detectable levels of AFB1 with values ranging from <1 ng/ml to4.23 ng/ml and with a mean value of 2 ± 0.98ng/ml. AFB1 was not detected in the serum sampled from any of the controls. Aspergillus flavus was the fungal species third most frequently found in the indoor air samples analyzed (7.2%) and was the most frequently isolated species in air samples containing only Aspergillus genus (74.5%). The presence of aflatoxigenic strains was only confirmed in outdoor air samples from one of the units, indicating the presence of a source inside the building in at least one case. Data indicate that AFB1 inhalation represents an additional risk in this occupational setting that needs to be recognized, assessed, and prevented.
- Occupational exposure to aflatoxin B1: new (old) occupational risk!Publication . Viegas, Susana; Veiga, Luísa; Almeida, Ana; Carolino, Elisabete; Figueiredo, Paula; Viegas, CarlaContrary to fungi, exposure to mycotoxins is not usually identified as a risk factor present in occupational settings. This is probably due to the inexistence of limits regarding concentration of airborne mycotoxins, and also due to the fact that these compounds are rarely monitored in occupational environments. Aflatoxin B1 (AFB1) is the most prevalent aflatoxin and is associated with carcinogenicity, teratogenicity, genotoxicity and immunotoxicity but only a few studies examined exposure in occupational settings. Workers can be exposed to high airborne levels during certain operations in specific occupational settings. Aim of study: The study aimed to assess exposure to AFB1 in three settings: poultry, swine production and waste management.
- Occupational exposure to Aflatoxin B1 in swine production and possible contamination sourcesPublication . Viegas, Susana; Veiga, Luísa; Figueiredo, Paula; Almeida, Ana; Carolino, Elisabete; Sabino, Raquel; Veríssimo, Cristina; Viegas, CarlaAlthough the adverse health consequences of ingestion of food contaminated with aflatoxin B1 (AFB1) are known, relatively few studies are available on the adverse effects of exposure in occupational settings. Taking this into consideration, our study was developed aiming to elucidate the possible effects of occupational exposure to AFB1 in Portuguese swine production facilities using a specific biomarker to assess exposure to AFB1. In total, 28 workers participated in this study, providing blood samples, and a control group (n = 30) was composed of subjects without any type of agricultural activity. Fungal contamination was also studied by conventional methods through air, surfaces, and new and used floor coverage. Twenty-one workers (75%) showed detectable levels of AFB1 with values ranging from <1 ng/ml to 8.94 ng/ml and with a mean value of 1.91 ± 1.68 ng/ml. In the control group, the AFB1 values were all below 1 ng/ml. Twelve different Aspergillus species were identified. Aspergillus versicolor presented the highest airborne spore counts (3210 CFU/m3) and was also detected in higher values in surfaces (>300 CFU/cm2). Data indicate that exposure to AFB1 occurs in swine barns, and this site serves as a contamination source in an occupational setting.
- Os cílios primários regulam os níveis de tiorredoxina redutase 1 e de yH2AX em resposta a níveis elevados de glucosePublication . Marques, Rira; Paiva, Mariana; Ginete, Catarina; Nolasco, Sofia; Marinho, Susana H.; Veiga, Luisa; Brito, Miguel; Soares, Helena; Carmona, BrunoA diabetes caracteriza-se por uma anormal capacidade de controlar o nível de glucose na corrente sanguínea, podendo levar a outras complicações, tais como hipertensão, doenças cardiovasculares, e retinopatia. A desregulação dos níveis de glucose na retina tem demonstrado aumentar os níveis de peróxido de hidrogénio, conduzindo a uma rutura na barreira sanguínea da retina, uma das causas de retinopatia diabética. O cílio primário é um organelo que demonstrou ter um papel no controlo do equilíbrio energético e da homeostase da glucose. Defeitos na estrutura e função dos cílios podem resultar no desenvolvimento de várias doenças, conhecidas como ciliopatias, e que incluem fenótipos como obesidade e diabetes. Neste trabalho pretendemos estudar o papel do aumento dos níveis de glucose na montagem de cílios primários em culturas de células do epitélio pigmentar da retina (RPE-1), bem como o papel dos cílios na resposta celular aos níveis elevados de glucose. Para isso, suplementámos os meios de crescimento das células RPE-1 com diferentes concentrações de glucose (5 mM, 25 mM e 5 mM de glucose + 20 mM manitol). Estas células também foram induzidas a montar cílios antes ou depois da suplementação com a glucose. Neste estudo observámos que a suplementação de glucose não afetou o número de células ciliadas, sendo que o comprimento dos cílios foi menor em células suplementadas com 25 mM de glucose. Também avaliámos os níveis nucleares de tiorredoxina redutase 1 (TXNRD1), uma das principais enzimas intervenientes na resposta ao stress oxidativo desencadeado pela hiperglicemia, e de γH2AX, um marcador celular de quebras no DNA e de senescência celular. Observámos que os níveis nucleares de TXNRD1 e de γH2AX são afetados pela adição de glucose e que a existência de cílios modula a resposta das células em resposta a níveis elevados de glucose. Estes resultados mostram que a presença de cílios primários afeta drasticamente a resposta celular às elevadas concentrações de glucose que provavelmente induzem o stress oxidativo, podendo ter um papel crucial no desenvolvimento de retinopatia diabética.
- Tobacco smoking have no influence on buccal telomere length among Portuguese master studentsPublication . Brito, Miguel; Azevedo, Patrícia; Coelho, André; Veiga, Luisa; Costa-Veiga, AnaIn Portugal, the average age of starting tobacco consumption is around 16 years, with an increase in consumption in recent years. The use of tobacco is a risk factor for age-related diseases, being one of the main causes of death and a risk factor for several chronic diseases, including diseases of the cardiovascular system, diabetes, and cancer. Different studies have shown a clear relationship between tobacco smoking and oxidative stress, which is one of the factors that accelerate the shortening of telomeres. The aim of this study was to evaluate the effect of tobacco smoking on the relative length of telomers in master students as a biomarker of health status. A cross-sectional study was performed by assessing relative Telomere Length (TL) in 131 master students. TL was evaluated from buccal swabs in 44 males and 89 females (aged between 18 and 52 years, mean 26.4) by multiplex quantitative Polymerase Chain Reaction (PCR). This technique consists in determining the relative ratio (T/S) between the telomere region copy number (T) and a single copy gene (S), albumin gene, using a relative standard curve. Mann-Whitney tests were used to detect TL differences between smokers and non-smokers and addiction levels (Light vs Moderate or Heavy). Statistical analysis was adjusted for age, sex, and BMI. Age and TL were negatively correlated as expected (Spearman Rho=-1.66, p=0.080). There were no statistically significant differences in TL between smokers and non-smokers, addiction levels or gender (Mann-Whitney tests, p>0.10). A negative association between buccal TL and tobacco smoking was not confirmed. One possible explanation can be the high turnover rate in buccal exfoliate cells relative to other cells such as lymphocytes. Although the association has not been signed with TL, the negative effect of tobacco consumption on the risk of cancer risk and respiratory alterations is largely confirmed. Future studies should include a higher number of participants. Although buccal exfoliate cells is a less invasive method, TL can be more specific using lymphocytes cells.
- Identification of genetic variants in 65 obesity related genes in a cohort of Portuguese obese individualsPublication . Ginete, Catarina; Serrasqueiro, Bernardo; Silva-Nunes, José; Veiga, Luisa; Brito, MiguelObesity is a major public health problem, which has a strong genetic component that interplays with environmental factors. Several genes are known to be implicated in the regulation of body weight. The identification of alleles that can be associated with obesity is a key element to control this pandemic. On the basis of a Portuguese population, 65 obesity-related genes are sequenced using Next-Generation Sequencing (NGS) in 72 individuals with obesity, in order to identify variants associated with monogenic obesity and potential risk factors. A total of 429 variants are identified, 129 of which had already been associated with the phenotype. Comparing our results with the European and Global frequencies, from the 1000 Genomes project, 23 potential risk variants are identified. Six new variants are discovered in heterozygous carriers: four missense (genes ALMS1-NM_015120.4:c.5552C>T; SORCS1-NM_001013031.2:c.1072A>G and NM_001013031.2: c.2491A>C; TMEM67-NM_153704.5:c.158A>G) and two synonymous (genes BBS1-NM_024649.4:c.1437C>T; TMEM67-NM_153704.5:c.2583T>C). Functional studies should be performed to validate these new findings and evaluate their penetrance and pathogenicity. Regardless of no cases of monogenic obesity being identified, this kind of investigational study is important when we are still trying to understand the etiology and pathophysiology of obesity. This will allow the identification of rare variants associated with obesity and the study of their prevalence in specific populational groups.
- Glucose homeostasis in obese women is not associated to unacylated ghrelin plasma levelsPublication . Veiga, Luisa; Brito, Miguel; Silva, Carina; Silva-Nunes, JoséIntroduction: Unacylated ghrelin (UAG) is the major form of circulating ghrelin. Initially considered as a nonfunctional peptide, soon after, UAG has been associated with an insulin-sensitizing action and to negative action on energy balance. The aim of this study was to analyze the association between the serum levels of UAG and glucose metabolism parameters in obese women, independently from the eventual influence of anthropometrics. Methods: One hundred lean and 254 obese Caucasian women were studied. Each woman was characterized by anthropometrics, fasting glucose, insulin, HbA1c, and UAG. In addition, obese women were subjected to a classic oral glucose tolerance test (oGTT) to assess glucose and insulin at 120 minutes. Insulin resistance was assessed by the homeostasis model assessment (HOMA-IR). Obese women were classified into three glycemic status subgroups (normoglycemia, prediabetes, and diabetes) according to HbA1c and fasting, and oGTT glucose values. Results: In comparison with the lean group, significantly lower levels of UAG were observed in obese women. However, no significant difference was observed through obesity classes I to III. UAG levels were not significantly different among glycemic status subgroups and did not show any association with glucose, insulin, HOMA-IR, or HbA1c. Conclusions: Although anthropometry can influence the level of the unacylated form of ghrelin, UAG plasma levels do not associate with glucose homeostasis parameters.
- Occupational exposure to Aflatoxin B1 in Portuguese swine farmsPublication . Viegas, Susana; Veiga, Luísa; Figueredo, P.; Almeida, Ana; Carolino, Elisabete; Viegas, CarlaIn 1987, the International Agency for Research on Cancer concluded that there was sufficient evidence for carcinogenicity of naturally occurring aflatoxins in humans. Regarding occupational exposure to this chemical agent, farmers and other agricultural workers present a higher risk due to airborne aflatoxin via inhalation of dust. This study was carried out in 7 swine farms located at the district of Lisbon, Portugal. Blood samples were collected from a total of 11 workers. In addition, a control group (n = 25) was included that conducted administrative tasks in an educational institution without any type of agricultural activity. Results obtained suggest that occupational exposure to AFB1 by inhalation occurs and represents an additional risk in this occupational setting that need to be recognized, assessed and, most important, prevented.
- Blood pressure and its circadian pattern in obese and lean premenopausal womenPublication . Silva-Nunes, José; Brito, Miguel; Veiga, LuisaBackground: Obesity is frequently referred to as an independent risk factor for high blood pressure and hypertension is very prevalent among obese people. The aims of this study were: to compare office-based and 24 h blood pressure (BP) and its circadian pattern between lean and obese women; to study correlations between BP, insulin resistance (IR), and markers of subclinical inflammation/early atherosclerosis. Material and methods: Eighty-eight lean and 107 otherwise healthy obese women were characterized for anthropometrics, BP (office-based determinations and 24 h ABPM), and for glucose, insulin, triglycerides, interleukin 6 (IL-6), tumor necrosis factor-alpha (TNF-a), high-sensitivity C reactive protein (hs-CRP), retinol-binding protein 4 (RBP-4), leptin, adiponectin, resistin, monocyte chemoattractant protein 1 (MCP-1), intercellular adhesion molecule 1 (ICAM-1), and vascular-cellular adhesion molecule 1 (VCAM-1). Insulin resistance was determined by homeostasis model assessment of insulin resistance (HOMA-IR), quantitative insulin sensitivity check index (QUICKI), and McAuley indexes (also Matsuda in obese). Results: The obese group presented higher office-based systolic/diastolic BP, systolic ambulatory blood pressure monitoring (ABPM), and more non-dippers. HOMA-IR and body fat was correlated to systolic (r2 = 0.176) and glucose to diastolic (p = 0.008; r = 0.256) ABPM. Age, QUICKI, and TNF-a was correlated with dipping (r2 = 0.172); adiponectin, age, BMI, and glucose to systolic (r2 = 0.226) and diastolic (r2 = 0.215) office-based BP. Concerning lean women, MCP-1 was associated with diastolic ABPM (p = 0.013; r = 0.267). Systolic office-based BP was associated with waist-to-hip ratio (p = 0.01; r = 0.273); this and RBP-4 was correlated with office-based diastolic BP (r2 = 0.12). Conclusion: Although relatively healthy, obese women present higher BP than lean. Anthropometrics, IR, and fasting glucose all influence BP in obesity; additionally, IR is involved in non-dipping. No strong correlation exists between BP/dipping and subclinical inflammation in either group of women.
- Occupational exposure to aflatoxin B1: the case of a poultry slaughterhousePublication . Viegas, Susana; Veiga, Luísa; Almeida, Ana; Santos, Mateus dos; Carolino, Elisabete; Viegas, CarlaAflatoxin B1 (AFB1) is a secondary metabolite produced by the fungi Aspergillus flavus and is the most potent hepatocarcinogen known in mammals and has been classified by the International Agency of Research on Cancer as Group 1 carcinogen. Although dietary exposure to AFB1 has been extensively documented, there are still few studies dedicated to the occupational exposure topic. In view of the recent findings regarding AFB1 occupational exposure in poultry production and other occupational settings related to animal production, it was considered relevant to clarify if there is also exposure in poultry slaughterhouses. Occupational exposure assessment to AFB1 was done with a biomarker of internal dose that measures AFB1 in the serum by enzyme-linked immunosorbent assay. Thirty workers from a slaughterhouse were enrolled in this study. A control group (n = 30) was also considered in order to know AFB1 exposure resulting from food consumption in a Portuguese population. Fourteen workers (47.0%) showed detectable levels of AFB1 with values from 1.06 ng mL-1 to 4.03 ng mL-1, with a mean value of 1.73 ng mL-1. No AFB1 was detected in the serum of individuals used as controls. Despite uncertainties regarding the exposure route that is contributing more to exposure (inhalation or dermal) is possible to state that exposure to AFB1 is occurring in the studied slaughterhouse unit. It seems that reducing AFB1 contamination in poultry production can have a positive result in reducing occupational exposure to this setting.