Trace elements, peripheral blood film, and gene expression status in adolescents living near an industrial area in the Colombian Caribbean Coastline.

BACKGROUND: Trace elements comprise both nutritionally essential and non-essential, and their presence in organisms plays important role in human health. OBJECTIVE: The aim of this study was to evaluate the levels of trace elements, together with cellular and molecular biomarkers, in adolescents from Tierrabomba Island, a Caribbean community located near an industrial area, comparing them with a group living in San Onofre, a reference community. METHODS: Hair and blood samples were obtained from 238 individuals aged 11-18 years old, 131 from Tierrabomba Island and 107 from San Onofre. Trace elements were quantified in hair using ICP-MS. The hematological evaluation was done by peripheral blood smears, and gene expression analysis was carried out through RT-PCR. RESULTS: Thirteen elements were analyzed; eight showed significant differences between sites. In Tierrabomba, arsenic (As) and tungsten (W) registered mean values greater than in San Onofre. In contrast, in the reference site, average values for boron (B), cobalt (Co), zinc (Zn), yttrium (Y), tin (Sn), and barium (Ba) were greater. The peripheral blood film showed differences between populations. Mean lymphocyte percentage was higher in the Island, while eosinophil and monocyte percentages displayed greater means in San Onofre. Some correlations between trace elements and hematological parameters were found, mainly with platelets in Tierrabomba. This trend remained even when partial correlation coefficients were adjusted for age. Levels of gene expression of metallothionein 1X (MT1X) and superoxide dismutase (SOD) registered significant differences between sites, being greater in Tierrabomba. Negative correlations between SOD and As were observed in both sampling sites. Discriminant analysis suggested sampling locations could be differentiated by Zn, Mo, Ba, and MT1X levels. SIGNIFICANCE: Trace elements and the relative gene expression associated with metal exposure are critical exposure biomarkers for coastal communities.

Hematological parameters and hair mercury levels in adolescents from the Colombian Caribbean.

Mercury (Hg) is one of the heavy metals of concern for fish-eating populations. This pollutant can be released from many sources and generates diverse toxic effects in humans. The aim of this study was to evaluate hematological parameters and their relationship with total Hg (T-Hg) levels in the hair of adolescents from Tierrabomba, an island close to an industrialized area, and also from San Onofre, a reference site. Blood and hair samples were collected from 194 individuals, aged 11-18 years old, as well as sociodemographic and dietary information. The hematological profile showed marked differences between the two sites. Mean values for almost all variables of the red blood cell line, as well as lymphocyte percentage (LYM%) and monocyte percentage (MID%), were greater in Tierrabomba. In contrast, red cell distribution width (RDW), white blood cells (WBC), granulocyte percentage (GRA%), and plateletcrit (PTC) were higher at the reference site. Total Hg mean in Tierrabomba was 1.10 ± 0.07 µg/g, while at San Onofre, it was 1.87 ± 0.11 µg/g. In both places, more than 49% of participants had Hg concentrations over the limit threshold (1 µg/g). Overall mean corpuscular hemoglobin concentration (MCHC) and T-Hg showed a negative correlation (r = - 0.162, p = 0.024). However, positive associations were observed between T-Hg and MID% for Tierrabomba (r = 0.193, p = 0.041), and between T-Hg and mixed cells (MID) for the reference site (r = 0.223, p = 0.044). A significant relationship was found for fish consumption frequency and T-Hg levels (r = 0.360, p < 0.001). These results indicate blood parameters may be affected by Hg even at low-level exposure.

Chemical control of Aedes aegypti: a historical perspective / Control químico de Aedes aegypti: una perspectiva histórica

Objective: To describe the use of chemical insecticides throughout history as the main tool to fight against Aedes aegypti, a vector of dengue virus. Methods: A text mining approach was conducted on databases, such as PUBMED and SCIENCE DIRECT, using the keywords “Aedes aegypti”, combined with the words “insecticides”, “resistance”, “organochlorines”, “organophosphates”, “carbamates” and “pyrethroids”. Results related to historical information dealing with the chemical control of Aedes aegypti, in particular those containing data on insecticide resistance for this species, were scrutinized and analyzed. Results: Different chemical groups have been utilized to control A. aegypti, including organochlorine, organophosphate, carbamate and pyrethroid insecticides. In general, the tendency has been to replace a particular pesticide, for which resistance had been detected, for a new one, mosquito-sensitive, and with little evidence of deleterious effects derived from its use. The spread of resistance has been registered in several countries of America, Asia and Africa. Two mechanisms have been highly cited to be responsible for the resistance; the increase activity of detoxifying enzymes, and structural changes in the insecticide target site, mostly within the central nervous system. Conclusion: Excessive use of chemical insecticides and the lack of dosing control have led to widespread resistance in A. aegypti, as no “safer” alternative chemical options are available for vector control in different countries, impacting human health.

Objetivo: Describir el uso de insecticidas químicos a través de la historia como la principal herramienta contra Aedes aegypti, un mosquito vector del virus del dengue. Métodos: Una búsqueda en minería de textos fue realizada en bases de datos como PubMedy Science Direct, utilizando las palabras clave “Aedes aegypti”, en combinación con “insecticidas”, “resistencia”, “organoclorados”, “organofosforados”,“carbamatos” y “piretroides”.Resultados afines con la información histórica relacionada con el control químico del mosquito Aedes aegypti, en particular las que contienen datos sobre la resistencia a insecticidas de esta especie, fueron examinados y analizados. Resultados: Diferentes grupos químicos han sido desarrollados para el control de A. aegypti, siendo los más utilizados organoclorados, organofosforados, carbamatos y piretroides. En general, la tendencia ha sido la de sustituir un pesticida particular, para el que ha sido detectado resistencia, por uno nuevo, mosquito-sensible, y con evidencia de efectos perjudiciales derivados de su uso. La propagación de la resistencia se ha registrado en varios países de América, Asia y África. Dos mecanismos han sido altamente referenciados de ser responsable de la resistencia, el aumento de actividad de las enzimas de desintoxicación, y los cambios estructurales en el sitio de destino de los insecticidas, en su mayoría dentro del sistema nervioso central. Conclusión: El uso excesivo de insecticidas químicos y la falta de control de dosificación han dado lugar a una resistencia generalizada en Aedes aegypti, y alternativas químicas “más seguras” no están disponibles para el control de vectores en diferentes países, afectando la salud humana.