Analysis of the cytotoxic and genotoxic effects in a population chronically exposed to coal mining residues.

During coal mining activities, many compounds are released into the environment that can negatively impact human health. Particulate matter, polycyclic aromatic hydrocarbons (PAHs), metals, and oxides are part of the complex mixture that can affect nearby populations. Therefore, we designed this study to evaluate the potential cytotoxic and genotoxic effects in individuals chronically exposed to coal residues from peripheral blood lymphocytes and buccal cells. We recruited 150 individuals who lived more than 20 years in La Loma-Colombia and 120 control individuals from the city of Barranquilla without a history of exposure to coal mining. In the cytokinesis-block micronucleus cytome (CBMN-Cyt) assay, significant differences in the frequency of micronucleus (MN), nucleoplasmic bridge (NPB), nuclear bud (NBUD), and apoptotic cells (APOP) were observed between the two groups. In the buccal micronucleus cytome (BM-Cyt) assay, a significant formation of NBUD, karyorrhexis (KRX), karyolysis (KRL), condensed chromatin (CC), and binucleated (BN) cells was observed in the exposed group. Considering the characteristics of the study group, a significant correlation for CBMN-Cyt was found between NBUD and vitamin consumption, between MN or APOP and meat consumption, and between MN and age. Moreover, a significant correlation for BM-Cyt was found between KRL and vitamin consumption or age, and BN versus alcohol consumption. Using Raman spectroscopy, a significant increase in the concentration of DNA/RNA bases, creatinine, polysaccharides, and fatty acids was detected in the urine of individuals exposed to coal mining compared to the control group. These results contribute to the discussion on the effects of coal mining on nearby populations and the development of diseases due to chronic exposure to these residues.

Association of buccal micronucleus cytome assay (BMNCyt) biomarkers with inorganic element concentration and genetic polymorphisms in welders.

Welding fumes are classified as carcinogenic to humans. The aim of the present study was to measure buccal micronucleus cytome assay biomarkers and to evaluate their association with inorganic elements and genetic polymorphisms (XRCC1, OGG1, XRCC3, GSTM1, and GSTT1) in welders (n = 98) and control individuals (n = 100). Higher levels of DNA damage and cell death were observed in the exposed group. Also, a significant correlation between the frequency of micronuclei and Na, Si, Cl, Ti, Cr, Zn and Mg concentrations. The formation of micronuclei, binucleated cells, cell death was associated with polymorphisms in repair pathways. The OGG1Ser326Cys and XRCC3 241Thr/Met genotypes were associated with cell death. Individuals with GSTM1 null genotype had a higher frequency of micronuclei. These results demonstrate that the deleterious effects of exposure to welding fumes are exacerbated by lifestyle habits, and genetic polymorphisms can influence DNA damage and cell death.

Cytokinesis-block micronucleus cytome (CBMN-CYT) assay and its relationship with genetic polymorphisms in welders.

Fumes generated in the welding process are composed of micrometric and nanometric particles that form when metal fumes condense. The International Agency for Research on Cancer established that many compounds derived from the welding process are carcinogenic to humans. Still, there are few studies related to the role of genetic polymorphisms. This work aimed to analyze the influence of OGG1 Ser326Cys, XRCC1 Arg280His, XRCC1 Arg194Thr, XRCC1 Arg399Gln, XRCC3 Thr241Met, GSTM1, and GSTT1 gene polymorphisms on DNA damage of 98 subjects occupationally exposed to welding fumes and 100 non exposed individuals. The results showed that individuals exposed to welding fumes with XRCC3 Thr241Thr, XRCC3 Thr241Met, and GSTM1 null genotypes demonstrated a significantly higher micronucleus frequency in lymphocytes. In contrast, individuals with XRCC1 Arg399Gln and XRCC1 Gln399Gln genotypes had significant levels of NPBs. OGG1 326 Ser/Cys, OGG1 326 Cys/Cys, XRCC1 194Arg/Thr, XRCC1 194Thr/Thr, and GSTT1 null genotypes exhibited significantly higher apoptotic values. Also, XRCC1 194Arg/Trp, XRCC1 194Thr/Thr, and GSTM1 null genotype carriers had higher necrotic levels compared to XRCC1 194Arg/Arg and GSTM1 nonnull carriers. Compositional analysis revealed the presence of iron, manganese, silicon as well as particles smaller than 2 µm that adhere to each other and form agglomerates. These results may be associated with a mixture of components, such as nitrogen dioxide, carbon monoxide, and metallic fumes, leading to significant DNA damage and cell death processes. These findings demonstrated the importance of the association between individual susceptibility and DNA damage levels due to occupational exposure to welding fumes; and constitute one of the first studies carried out in exposed workers from Colombia.

Polimorfismos de los genes del sistema leptina-melanocortina asociados con la obesidad en la población adulta de Barranquilla / Polymorphisms of leptin-melanocortin system genes associated with obesity in an adult population from Barranquilla

Introducción. La obesidad se considera un grave problema de salud pública y por ello se hacen esfuerzos en la búsqueda de genes como el LEP, el LEPR y el MC4R del sistema leptina-melanocortina, el cual opera en la regulación neuroendocrina de la ingestión y el equilibrio energético e influye en la patogenia de la enfermedad. Los resultados contradictorios en torno a la asociación de estos genes con la obesidad plantean la necesidad de nuevas investigaciones. Objetivo. Analizar los polimorfismos rs2167270 del gen LEP, rs1137101 del gen LEPR y rs17782313 del gen MC4R asociados con la obesidad y sus variables clínicas y bioquímicas en una muestra de pacientes adultos de Barranquilla. Materiales y métodos. Se estudiaron 111 personas obesas y 155 no obesas como controles. Los polimorfismos se determinaron mediante reacción en cadena de la polimerasa (PCR) en tiempo real. Se tomaron las medidas antropométricas, se evaluó la presión arterial y se hicieron pruebas bioquímicas. Resultados. No se encontraron diferencias estadísticas en la frecuencia alélica y genotípica de los polimorfismos en los grupos estudiados. En cuanto a las variables clínicas y bioquímicas, el genotipo CC del polimorfismo rs17782313 del gen MC4R, se asoció con un aumento de la presión arterial sistólica y, el alelo T y su genotipo homocigoto, con una disminución del colesterol HDL en los obesos. No se evidenció ningún efecto de los otros polimorfismos en estas variables. Conclusiones. Los polimorfismos rs2167270 del gen LEP, rs1137101 del gen LEPR y rs17782313 del gen MC4R, no se asociaron con obesidad en la población analizada. Se encontró que el polimorfismo rs17782313 del gen MC4R influyó en el aumento de la presión arterial sistólica y la disminución del colesterol HDL en las personas obesas.

Introduction: Obesity is considered a serious public health problem. Efforts have been directed to search for candidate genes such as LEP, LEPR, and MC4R involved in the leptin- melanocortin system. The neuroendocrine regulation of these genes on energy intake and balance influences the pathogenesis of this disease. Contradictory results regarding the association of these genes with obesity raise the need for new research. Objective: To analyze the association between obesity and LEP rs2167270, LEPR rs1137101, and MC4R rs17782313 polymorphisms and the clinical and biochemical variables in obese adults from Barranquilla, Colombia. Materials and methods: We analyzed 111 obese adults and 155 non-obese individuals as controls. The polymorphisms were determined by real-time PCR. Besides, anthropometric measures, blood pressure, and biochemical tests were evaluated. Results: No statistical differences were found in allele and genotype frequencies of gene polymorphisms between groups. The CC genotype of MC4R rs17782313 polymorphism was associated with increased systolic blood pressure and T allele and TT genotype, with decreased HDL cholesterol in obese adults. The effect of the other polymorphisms on these variables was not evidenced. Conclusions: LEP rs2167270, LEPR rs1137101, and MC4R rs17782313 polymorphisms were not associated with obesity in the population under study. MC4R rs17782313 polymorphisms were associated with an increase in systolic blood pressure and a decrease in HDL cholesterol.

DNA repair and metabolic gene polymorphisms affect genetic damage due to diesel engine exhaust exposure.

Diesel engine exhaust (DEE) is a complex mixture of toxic gases, halogenated aromatic hydrocarbons, alkyl polycyclic aromatic hydrocarbons, polycyclic aromatic hydrocarbons, benzene derivatives, metals and diesel exhaust particles (DEPs) generated from the incomplete combustion of diesel fuel. Many of the compounds in this mixture can cause oxidative damage to DNA and are considered carcinogenic for humans. Further, chronic DEE exposure increases risks of cardiovascular and pulmonary diseases. Despite these pervasive health risks, there is limited and inconsistent information regarding genetic factors conferring susceptibility or resistance to DEE genotoxicity. The present study evaluated the effects of polymorphisms in two base excision repair (BER) genes (OGG1 Ser326Cys and XRCC1 Arg280His), one homologous recombination (HRR) gene (XRCC3 Thr241Met) and two xenobiotic metabolism genes (GSTM1 and GSTT1) on the genotoxicity profiles among 123 mechanics exposed to workplace DEE. Polymorphisms were determined by PCR-RFLP. In comet assay, individuals with the GSTT1 null genotype demonstrated significantly greater % tail DNA in lymphocytes than those with non-null genotype. In contrast, these null individuals exhibited significantly lower frequencies of binucleated (BN) cells and nuclear buds (NBUDs) in buccal cells than non-null individuals. Heterozygous hOGG1 326 individuals (hOGG1 326 Ser/Cys) exhibited higher buccal cell NBUD frequency than hOGG1 326 Ser/Ser individuals. Individuals carrying the XRCC3 241 Met/Met polymorphism also showed significantly higher buccal cell NBUD frequencies than those carrying the XRCC3 241 Thr/Thr polymorphism. We found a high flow of particulate matter with a diameter of < 2.5 µm (PM2.5) in the workplace. The most abundant metals in DEPs were iron, copper, silicon and manganese as detected by transmission electron microscopy-energy-dispersive X-ray spectroscopy (TEM-EDX). Scanning electron microscopy (SEM-EDS) revealed particles with diameters smaller than PM2.5, including nanoparticles forming aggregates and agglomerates. Our results demonstrate the genotoxic effects of DEE and the critical influence of genetic susceptibility conferred by DNA repair and metabolic gene polymorphisms that shed light into the understanding of underlying mechanisms.

Extraction, isolation and in vitro evaluation of affinisine from Tabernaemontana catharinensis in human melanoma cells.

Plant compounds have been identified as new drug prototypes. In this line, this work aimed to isolate the indole alkaloid affinisine from Tabernaemontana catharinensis and test its antitumor activity. The alkaloid was isolated by silica gel open column chromatography from the ethanolic extract of the stem of T. catharinensis. Afterwards, this molecule was characterized by high-resolution mass spectrometry and nuclear magnetic resonance. In the next step, the cytotoxicity of the compound was tested against human melanoma cell lines (A375, WM1366 and SK-MEL-28) and a normal skin cell line (CCD-1059Sk) using a MTT (3-4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay. Cells treated with affinisine were evaluated by flow cytometry to analyze apoptosis and the induction of cell cycle arrest, to evaluate the dead mechanism. The metabolite was isolated in a 0.2% yield relative to the extract. Cytotoxic activity of the molecule was observed at 48 h, resulting in considerable growth inhibition rates in melanoma cells, especially in WM1366, which had the lowest IC50 (32.86 ± 2.54 µg/mL). The apoptosis rate was lower in A375 (56.66 and 86.71% with 57 and 65 µg/mL, respectively). Moreover, affinisine was able to significantly induce cell cycle arrest in different phases in the A375 and WM1366 cell lines. However, in SK-MEL-28 cells, cycle arrest was not observed. In summary, this compound significantly decreased the viability of tumor cells in a dose- and time-dependent manner for all evaluated lineages, reduced cell viability by the apoptosis mechanism and presented prominent activities of cell cycle arrest. In this way, the use of antineoplastic agents is among the most widely used therapeutic measures for the control and treatment of cancer. Affinisine is a promising prototype in the search for new drugs to treat cancer.

Cytotoxic and genotoxic effects in mechanics occupationally exposed to diesel engine exhaust.

Diesel engine exhaust (DEE), which is the product of diesel combustion, is considered carcinogenic in humans. It comprises toxic gases, polycyclic aromatic hydrocarbons (PAHs) and particulate matter which can reach the pulmonary parenchyma and trigger various diseases, including cancer. The aim of the present study was to evaluate the potential cytotoxic and genotoxic effects of DEE exposure on peripheral blood and buccal epithelial cells in mechanics occupationally exposed to DEE. We recruited 120 exposed mechanics and 100 non-exposed control individuals. Significant differences were observed between the two groups in terms of percentage of tail DNA and damage index (DI) in the alkaline comet assay; levels of biomarkers by cytokinesis-block micronucleus cytome (CBMN-Cyt) assay; frequency of micronucleus (MN), nucleoplasmic bridge (NPB), nuclear bud (NBUD) and apoptotic cells (APOP) and levels of biomarkers for micronucleus, karyorrhexis (KRX), karyolysis (KRL) and condensed chromatin (CC) by the buccal micronucleus cytome (BM-Cyt) assay. A significant and positive correlation was found between the frequency of MN in lymphocytes and buccal cells in the exposed group. Also, there was a significant correlation between age and percentage of tail DNA and DI in the comet assay, APOP and MN in the CBMN-Cyt assay and NBUD and MN in the BM-Cyt assay. Additionally, we found a positive and significant correlation of MN frequency in lymphocytes and buccal cells and age and MN frequency in lymphocytes with the time of service (years). Regarding lifestyle-related factors, a significant correlation was observed between meat and vitamin consumption and NBUD formation on CBMN-Cyt and between meat consumption and MN formation on CBMN-Cyt. Of the BM-Cyt biomarkers, there was a correlation between alcohol consumption and NBUD formation and between binucleated cell (BN), pyknosis (PYC), CC and KRL occurrence and family cancer history. These results are the first data in Colombia on the cytotoxic and genotoxic effects induced by continuous exposure to DEE and thus showed the usefulness of biomarkers of the comet, CBMN-Cyt and BM-Cyt assays for human biomonitoring and evaluation of cancer risk in the exposed populations.