Selenium Levels in Occupationally Lead Exposed Workers of Rajasthan.

Occupational and environmental exposure to Lead (Pb) has profound detrimental effects on human health. The underlying mechanism of lead toxicity is not fully understood but antioxidant imbalance is suggested to be a key player in its pathogenesis. Selenium (Se) being a vital component of antioxidant system in the body, has been linked to many health benefits in humans. Selenium levels in occupationally Pb exposed individuals has not been explored in Indian setup. The aim of the present study is to find out the association of Se with blood lead levels (BLL) in occupationally Pb exposed individuals. In the present study 91 occupationally Pb exposed workers employed in handicraft and paint industries were recruited after taking informed consent. The demographic details were noted on self-generated questionnaire. The BLL and Se were measured using GFAAS (Thermofisher Scientific, Waltham, USA). Samples were run in duplicate after ensuring quality control. The mean Pb and Se levels in the study population were 5.5 ± 5.6 µg/dl (0.42-31.76 µg/dl) and 105.5 ± 23.8 µg/dl (46.4-189.6 µg/dl) respectively. BLL was significantly higher in tobacco chewers and those occupationally exposed to Pb for more than 5 years. Significantly low Se levels were observed in individuals with high BLL. Statistically significant negative linear relationship was noted between BLL and Se. The negative correlation of Se with BLL indicates the antagonistic relationship between these metals.

Risk Factors for Lead Toxicity and its Effect on Neurobehavior in Indian Children.

Lead (Pb) is profoundly used heavy metal despite its known toxic effects. Children in particular are more susceptible to Pb toxicity. Thus, the present study was carried out to estimate the prevalence of lead toxicity in Indian children, to observe serum levels of biochemical parameters and to evaluate psychopathological implications of Pb toxicity using population specific scale-Childhood Psychopathological Measurement Schedule (CPMS) in children. Children between 9 and 15 years of age were included in the study (N = 70). Demographic details and information regarding the source of lead exposure were collected using a self-made questionnaire. All biochemical investigations were performed in Beckman Coulter Auto-analyser AU680 and Blood Lead Levels (BLL) were estimated by Graphite Furnace Atomic Absorption Spectrophotometer. The neurobehavioral state of the children was assessed by a population-specific scale i.e., CPMS, which evaluates for neurobehavior under 8 factors, titled, Low intelligence with behavioural problems, Conduct disorder, Anxiety, Depression, Psychotic symptoms, Special symptoms, Physical illness with emotional problems, and Somatization. The median BLL of the study population was 4.9 µg/dL. Habit of frequently consuming roadside food, proximity of residence to vehicular traffic and educational status of the mother were observed to be significant contributing factors for high BLL (≥ 5 µg/dL). Serum alkaline phosphatase (P = 0.02) and phosphorous levels (P = 0.04) were significantly lower in children belonging to high BLL group. A significantly high adverse neurobehavioral score was observed in high BLL group children compared to low BLL group (P < 0.05). There was high prevalence of Pb toxicity with 50% of children having BLL > 5 µg/dL. Further, certain lifestyle characteristics such as proximity of residence to vehicular traffic, frequent consumption of roadside food and lower educational status of the mother could be possible risk factors for higher Pb exposure in children. Evaluation of neurobehavior in children with high BLL revealed a high prevalence of adverse neurobehavior in them when compared to children in low BLL group.

Selenium, oxidative stress and inflammatory markers in handicraft workers occupationally exposed to lead.

Occupational Lead (Pb) exposure increases reactive oxygen species and has been reported to impact inflammatory response by modulating intracellular signaling pathways. Selenium (Se) a vital component of the antioxidant system that plays an important role in modulating cytokines. The present study evaluated Se, malondialdehyde (MDA), total antioxidant capacity (TAC) and cytokines (IL-6, TNF-α, IL-10, IL-17a) in 81 Pb exposed male workers. The median (range) of blood lead level (BLL) and Se were 5 (0.50-31.76) µg/dL and 104 (46.9-189.6) µg/L respectively. The Se, TAC levels were decreased, and MDA, IL-6 levels were increased in the high Pb group (>5µg/dL). Blood lead level independently predicted oxidative stress and antioxidant status. Selenium, TAC levels negatively and MDA, IL-6 levels positively correlated with BLL. Association of Se with IL-6 and TAC suggests some probable role of Se in the underlined mechanism of Pb toxicity.

Selenium to selenoproteins - role in COVID-19.

The disruption of antioxidant defense has been demonstrated in severe acute respiratory syndrome due to SARS-CoV infection. Selenium plays a major role in decreasing the ROS produced in response to various viral infections. Selenoprotein enzymes are essential in combating oxidative stress caused due to excessive generation of ROS. Selenium also has a role in inhibiting the activation of NF-κB, thus alleviating inflammation. In viral infections, selenoproteins have also been found to inhibit type I interferon responses, modulate T cell proliferation and oxidative burst in macrophages, and inhibit viral transcriptional activators. Potential virally encoded selenoproteins have been identified by computational analysis in different viral genomes like HIV-1, Japanese encephalitis virus (JEV), and hepatitis C virus. This review discusses the role and the possible mechanisms of selenium, selenoproteins, and virally encoded selenoproteins in the pathogenicity of viral infections. Identification of potential selenoproteins in the COVID 19 genome by computational tools will give insights further into their role in the pathogenesis of viral infections.