Differential Expression of AhR in Peripheral Mononuclear Cells in Response to Exposure to Polycyclic Aromatic Hydrocarbons in Mexican Women.

The exposure to air pollutants causes significant damage to health, and inefficient cooking and heating practices produce high levels of household air pollution, including a wide range of health-damaging pollutants such as fine particles, carbon monoxide and PAHs. The exposure to PAHs has been associated with the development of neoplastic processes, asthma, genotoxicity, altered neurodevelopment and inflammation. The effects on the induction of proinflammatory cytokines are attributed to the activation of AhR. However, the molecular mechanisms by which the PAHs produce proinflammatory effects are unknown. This study was performed on a group of 41 Mexican women from two rural communities who had stoves inside their houses, used wood as biomass fuel, and, thus, were vulnerable. According to the urinary 1-OHP concentration, the samples were stratified into two groups for determination of the levels of TNF-α, AhR, CYP1B1, miR-125b and miR-155 expression. Our results showed that the CYP1B1, TNF-α, miR-125b and miR-155 expression levels were not statistically different between women with the lowest and highest levels of 1-OHP. Interestingly, high levels of PAHs promoted augmented expression of AhR, which is a protein involved in the modulation of inflammatory pathways in vivo, suggesting that cell signaling of AhR may be implicated in several pathogenesis processes.

5p and 3p Strands of miR-34 Family Members Have Differential Effects in Cell Proliferation, Migration, and Invasion in Cervical Cancer Cells.

The micro RNA (miR)-34 family is composed of 5p and 3p strands of miR-34a, miR-34b, and miR-34c. The 5p strand's expression and function is studied in cervical cancer. The 3p strand's function and regulation remain to be elucidated. To study the function of the passenger strands of miR-34 family members, we overexpressed 5p and 3p strands using a synthetic miRNA in cervical cell lines. Cell proliferation was evaluated using crystal violet. Migration and invasion were tested using transwell assays, Western blot, and zymography. Possible specific targets and cell signaling were investigated for each strand. We found that miR-34a-5p inhibited proliferation, migration, and cell invasion accompanied by matrix metalloproteinase 9 (MMP9) activity and microtubule-associated protein 2 (MAP2) protein reduction. We also found that miR-34b-5p and miR-34c-5p inhibit proliferation and migration, but not invasion. In contrast, miR-34c-5p inhibits MMP9 activity and MAP2 protein, while miR-34b-5p has no effect on these genes. Furthermore, miR-34a-3p and miR-34b-3p inhibit proliferation and migration, but not invasion, despite the later reducing MMP2 activity, while miR-34c-3p inhibit proliferation, migration, and cell invasion accompanied by MMP9 activity and MAP2 protein inhibition. The difference in cellular processes, MMP2 and MMP9 activity, and MAP2 protein inhibition by miR-34 family members suggests the participation of other regulated genes. This study provides insights into the roles of passenger strands (strand*) of the miR-34 family in cervical cancer.

Persistent Organic Pollutants and Heavy Metal Concentrations in Soil from the Metropolitan Area of Monterrey, Nuevo Leon, Mexico.

The purpose of this study was to assess the levels of polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs), dichlorodiphenyltrichloroethane (DDT), dichlorodiphenyldichloroethane (DDE), and four heavy metals (arsenic, cadmium, and lead) in outdoor surface soils (50 samples) collected from the metropolitan area of Monterrey in Mexico. Total PBDEs levels ranged from 1.80 to 127 µg/kg, with mean total PBDEs level of 14.2 ± 21.5 µg/kg (geometric mean ± standard deviation). For PCBs, the mean total level in the studied soils was 23.5 ± 20.2 µg/kg (range 4.0-65.5 µg/kg). An important finding in our study was that all soil samples (100%) had detectable levels of the metabolite p,p'-DDE. Moreover, the mean total DDT level (∑p'p-DDT and p'p-DDE) was approximately 132 ± 175 µg/kg. The mean levels for arsenic, cadmium, and lead in soil were 5.30 ± 1.35 (range 1.55-7.85) mg/kg, 2.20 ± 1.20 (range 0.65-6.40) mg/kg, and 455 ± 204 (range 224-1230) mg/kg, respectively. Our study has several limitations, the most notable of which is the small sample of soils evaluated. However, this screening study provided concentration data for the occurrence of POPs and four heavy metals in soil from the metropolitan area of Monterrey, Nuevo Leon, Mexico, and taking into consideration that soil is an important pathway of exposure for people, a biomonitoring program for the surveillance of the general population in the metropolitan area of Monterrey, Nuevo Leon is deemed necessary.

Concentrations of persistent organic pollutants (POPs) in human blood samples from Mexico City, Mexico.

Studies in Mexico have demonstrated exposure to persistent organic pollutants (POPs) in people living in different sites through the country. However, studies evaluating exposure to POPs in people living in Mexico City (one of most contaminated places in the world) are scarce. Therefore, the aim of this study was to assess the levels of polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs), dichlorodiphenyltrichloroethane (DDT) and its metabolite dichlorodiphenyldichloroethylene (DDE) in the blood as exposure biomarkers in people living in Mexico City. A total of 123 participants (blood donors aged 20-60 years) were recruited during 2010 in Mexico City. Quantitative analyses of blood samples were performed using gas chromatography coupled with mass spectrometry. Levels of the assessed compounds ranged from non-detectable (

DDT and DDE concentrations in the blood of Mexican children residing in the southeastern region of Mexico.

The aim of this study was to assess the levels of dichlorodiphenyltrichloroethane (DDT) and dichlorodiphenyldichloroethylene (DDE) in the blood of children living in the southeastern region of Mexico. In this study, we found high levels of DDT and its principal metabolite (DDE) in the blood of children residing in the communities studied. The levels of total DDT found in our study ranged from 4,676.4 ng/g lipid to 64,245.2 ng/g lipid. All of the children in the study had detectable levels of DDT and/or DDE. In conclusion, our data indicate that children living within the study areas are exposed to high levels of DDT and DDE. Moreover, these results can be used as a trigger to revisit local policies on environmental exposures.

Assessment of the levels of persistent organic pollutants and 1-hydroxypyrene in blood and urine samples from Mexican children living in an endemic malaria area in Mexico.

The aim of this study was to evaluate the exposure levels to persistent organic pollutants and 1-hydroxypyrene in children living in an endemic malaria zone in Mexico. The blood levels for 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (DDT), 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (DDE) and lindane ranged from 15.4 to 17,886.5 ng/g lipid, 6,624.3 to 100,119.0 ng/g lipid, and 351.1 to 6,153.8 ng/g lipid, respectively. For total polychlorinated biphenyls the blood levels ranged from 2,584.9 to 14,547.9 ng/g lipid. Regarding urinary 1-hydroxypyrene levels, the mean level was 2.9 ± 3.1 µmol/mol creatinine. In conclusion, the children in our study are exposed to levels higher than normal to mixtures of environmental contaminants.