Comparative Biomonitoring of Arsenic Exposure in Mothers and Their Neonates in Comarca Lagunera, Mexico.

Multiple comorbidities related to arsenic exposure through drinking water continue to be public problems worldwide, principally in chronically exposed populations, such as those in the Comarca Lagunera (CL), Mexico. In addition, this relationship could be exacerbated by an early life exposure through the placenta and later through breast milk. This study conducted a comparative analysis of arsenic levels in multiple biological samples from pregnant women and their neonates in the CL and the comparison region, Saltillo. Total arsenic levels in placenta, breast milk, blood, and urine were measured in pregnant women and their neonates from rural areas of seven municipalities of the CL using atomic absorption spectrophotometry with hydride generation methodology. The average concentrations of tAs in drinking water were 47.7 µg/L and 0.05 µg/L in the exposed and non-exposed areas, respectively. Mean levels of tAs were 7.80 µg/kg, 77.04 µg/g-Cr, and 4.30 µg/L in placenta, blood, urine, and breast milk, respectively, in mothers, and 107.92 µg/g-Cr in neonates in the exposed group, which were significantly higher than those in the non-exposed area. High levels of urinary arsenic in neonates were maintained 4 days after birth, demonstrating an early arsenic exposure route through the placenta and breast milk. In addition, our study suggested that breastfeeding may reduce arsenic exposure in infants in arsenic-contaminated areas. Further studies are necessary to follow up on comorbidities later in life in neonates and to provide interventions in this region.

Cranial bone regeneration with collagen type I and polyvinylpyrrolidone (Fibroquel®) combined with hyaluronic acid in Wistar rats: morphological study / Regeneración ósea craneal con colágeno tipo I y polivinilpirrolidona (Fibroquel®) combinado con ácido hialurónico en ratas Wistar: estudio morfológico

SUMMARY: The purpose of this study was to evaluate by morphological methods, if a mixture of Fibroquel® and hyaluronic acid implanted in an animal model of cranial bone injury could promote bone regeneration. 12 Wistar rats were divided in three groups, control group, bone injury without treatment and bone injury with treatment. After experimental period, bone samples were taken and stained with H & E, Masson trichrome, PAS-D, immunohistochemistry with anti-PCNA monoclonal antibody and applied a semiquantitative morphometric method. Treatment group showed extensive areas of collagen fibers in contact with normal bone tissue, areas of normal histology, PAS positive material and less cellular proliferation. We demonstrated for the first time that a mixture of Fibroquel® and hyaluronic acid implanted in an animal model of cranial bone injury promotes bone regeneration.

RESUMEN: El propósito de este estudio fue evaluar por métodos morfológicos, si una mezcla de Fibroquel® y ácido hialurónico implantado en un modelo animal de lesión del hueso craneal podría promover la regeneración ósea. Se dividieron 12 ratas Wistar en tres grupos, grupo control, lesión ósea sin tratamiento y lesión ósea con tratamiento. Después del período experimental, se tomaron muestras de hueso y se tiñeron con H & E, tricrómico de Masson, PAS-D, inmunohistoquímica con anticuerpo monoclonal anti-PCNA y se aplicó un método morfométrico semicuantitativo. El grupo de tratamiento mostró áreas extensas de fibras de colágeno en contacto con tejido óseo normal, áreas de histología normal, material PAS positivo y menor proliferación celular. Demostramos por primera vez que una mezcla de Fibroquel® y ácido hialurónico implantado en un modelo animal de lesión del hueso craneal promueve la regeneración ósea.

Transgenerational effects in DNA methylation, genotoxicity and reproductive phenotype by chronic arsenic exposure.

An emerging concern is the influences of early life exposure to environmental toxicants on offspring characteristics in later life. Since recent evidence suggests a transgenerational transference of aberrant phenotypes from exposed-parents to non-exposed offspring related to adult-onset diseases including reproductive phenotype. The transgenerational potential of arsenic a well know genotoxic and epigenetic modifier agent has not been assessed in mammals until now. In this experimental study, we evaluated the transgenerational effects of arsenic in a rat model with chronic exposure to arsenic. Rats chronically exposed to arsenic in drinking water (1 mg As2O3/mL) (F0) were mated to produce the arsenic lineage (F1, F2, and F3). The arsenic toxic effects on were evaluated over the four generations by analyzing the DNA methylation percentage, genotoxicity in WBC and physical and reproductive parameters, including sperm quality parameters and histopathological evaluation of the gonads. Chronic exposure to arsenic caused genotoxic damage (F0-F3) different methylation patterns, alterations in physical and reproductive parameters, aberrant morphology in the ovaries (F0 and F1) and testicles (F1-F3), and a decrease in the quality of sperm (F0-F3, except F2). Parental chronic arsenic exposure causes transgenerational genotoxicity and changes in global DNA methylation which might be associated with reproductive defects in rats. Combined with recent studies reveal that disturbances in the early life of an individual can affect the health of later generations.

Development of a Novel Ex-vivo 3D Model to Screen Amoebicidal Activity on Infected Tissue.

Amoebiasis is a parasitic disease that causes thousands of deaths every year, its adverse effects and resistance to conventional treatments have led to the search of new treatment options, as well as the development of novel screening methods. In this work, we implemented a 3D model of intestine and liver slices from hamsters that were infected ex vivo with virulent E. histolytica trophozoites. Results show preserved histology in both uninfected tissues as well as ulcerations, destruction of the epithelial cells, and inflammatory reaction in intestine slices and formation of micro abscesses, and the presence of amoebae in the sinusoidal spaces and in the interior of central veins in liver slices. The three chemically synthetized compounds T-001, T-011, and T-016, which act as amoebicides in vitro, were active in both infected tissues, as they decreased the number of trophozoites, and provoked death by disintegration of the amoeba, similar to metronidazole. However, compound T-011 induced signs of cytotoxicity to liver slices. Our results suggest that ex vivo cultures of precision-cut intestinal and liver slices represent a reliable 3D approach to evaluate novel amoebicidal compounds, and to simultaneously detect their toxicity, while reducing the number of experimental animals commonly required by other model systems.

Protective effects of phenolic acids on mercury-induced DNA damage in precision-cut kidney slices.

OBJECTIVES: Precision-cut tissue slices are considered an organotypic 3D model widely used in biomedical research. The comet assay is an important screening test for early genotoxicity risk assessment that is mainly applied on in vitro models. The aim of the present study was to provide a 3D organ system for determination of genotoxicity using a modified method of the comet assay since the stromal components from the original tissue make this technique complicated. MATERIALS AND METHODS: A modified comet assay technique was validated using precision-cut hamster kidney slices to analyze the antigenotoxic effect of the phenolic compounds caffeic acid, chlorogenic acid, and rosmarinic acid in tissue slices incubated with 15 µM HgCl2. Cytotoxicity of the phenolic compounds was studied in Vero cells, and by morphologic analysis in tissue slices co-incubated with HgCl2 and phenolic compounds. RESULTS: A modification of the comet assay allows obtaining better and clear comet profiles for analysis. Non-cytotoxic concentrations of phenolic acids protected kidney tissue slices against mercury-induced DNA damage, and at the same time, were not nephrotoxic. The highest protection was provided by 3 µg/ml caffeic acid, although 6 µg/ml rosmarinic and 9 µg/ml chlorogenic acids also exhibited protective effects. CONCLUSION: This is the first time that a modification of the comet assay technique is reported as a tool to visualize the comets from kidney tissue slices in a clear and simple way. The phenolic compounds tested in this study provided protection against mercury-induced genotoxic damage in precision-cut kidney slices.

Evaluación de la respuesta inflamatoria en ratas Wistar a TheraCalTM LC implantado vía subcutánea / Evaluation of the inflammatory response in Wistar rats to TheraCalTM LC implanted subcutaneously

El Theracal TM LC es un cemento silicato de calcio (Ca) modificado con resina (SMCR) que ha demostrado ser un material ideal para el tratamiento dentino-pulpar por su alta tasa de formación de calcio. Los biomateriales por su contenido de Ca tienden a tener un aumento en su biodisponibilidad, estimulando la formación del puente dentario atreves de las células involucradas en la formación de tejidos mineralizados, promoviendo la diferenciación de fibroblastos en odontoblastos y aumentando la actividad de la enzima pirofostasa responsable en la mineralización de la dentina. El presente estudio con el objetivo de evaluar la respuesta inflamatoria a Theracal TM LC subcutáneamente en ratas Wistar. Fueron usados seis ratas cepa Wistar en las cuales se realizaron cuatro bolsillos quirúrgicos subcutáneos. Cada uno de estos bolsillos se determinó como cuadrante distinto, conteniendo los siguientes implantes: 1 Theracal TM LC en tubo polietileno, 2 tubo de polietileno, 3 Theracal TM LC directo y 4 como control. Las muestras histológicas se procesaron y se evaluaron distintos tipos celulares mediante conteo a microscopio de luz a 100X utilizando las tinciones H&E y AT pH 2.3. Los resultados mostraron que existen diferencias significativas en todos los tipos celulares observados durante los diferentes tiempos de exposición. Las diferencias en los tipos celulares observados podrían ser debido al tiempo de exposición al Theracal TM LC, al tubo polietileno y a ambos. El tejido evaluado del implante del tubo polietileno y al tubo polietileno con Theracal TM LC, presentan mayor respuesta inflamatoria, a diferencia en el tejido implantado con Theracal TM LC directamente.

TheraCalTM LC is a resin-modified calcium silicate (Ca) resin (SMCR) that has proven to be an ideal material for dentin-pulp treatment due to its high rate of calcium formation. Biomaterials due to their Ca content tend to have an increase in their bioavailability, stimulating the formation of the dental bridge through the cells involved in the formation of mineralized tissues, promoting the differentiation of fibroblasts in odontoblasts and increasing the activity of the pyrophosphate enzyme responsible in dentin mineralization. The present study aimed to evaluate the inflammatory response to TheracalTM LC subcutaneously in Wistar rats. Six Wistar strain rats were used in which four subcutaneous surgical pockets were made. Each of these pockets was determined as a different quadrant, containing the following implants: 1 TheracalTM LC in polyethylene tube, 2 polyethylene tubes, 3 TheracalTM LC direct and 4 as control. The histological samples were processed, and different cell types were evaluated by light microscopy at 100X using the H&E and AT pH 2.3 stains. The results showed that there are significant differences in all cell types observed during the different exposure times. The differences in the cell types observed could be due to the exposure time to TheracalTM LC, to the polyethylene tube and to both. The evaluated tissue of the polyethylene tube implant and the polyethylene tube with TheracalTM LC present a greater inflammatory response, unlike in the tissue implanted with TheracalTM LC directly.

Telomere length analysis in residents of a community exposed to arsenic.

Differentiated cells telomere length is an indicator of senescence or lifespan; however, in peripheral blood leukocytes the relative shortening of the telomere has been considered as a biological marker of aging, and lengthening telomere as an associated risk to cancer. Individual's age, type of tissue, lifestyle, and environmental factors make telomere length variable. The presence of environmental carcinogens such as arsenic (As) influence as causal agents of these alterations, the main modes of action for As described are oxidative stress, reduction in DNA repair capacity, overexpression of genes, alteration of telomerase activity, and damage to telomeres. The telomeres of leukocytes resulting a finite capacity of replication due to the low or no activity of the telomerase enzyme, therefore, elongation telomere in this kind of cells is a potential biological marker associated with the development of chronic diseases and carcinogenesis.