Long-Term Excessive Selenium Supplementation Affects Gene Expression in Esophageal Tissue of Rats.

Esophageal cancer is one of the leading causes of cancer death and the seventh most prevalent cancer worldwide. Considering the positive association of high selenium with the prevalence of esophageal cancer, we have investigated the effect of high doses of selenium on gene expression in the normal esophageal tissue of rats. Twenty male rats were randomly divided into four groups: control group, group 2 mg Se/L, 10 mg Se/L, and 20 mg Se/L rats fed with a basal basic diet and 2, 10, and 20 mg Se/L as sodium selenite in drinking water, respectively, for 20 weeks. Serum malondialdehyde and glutathione peroxidase activity were measured. Moreover, the expression and concentration of the cyclin D1, cyclin E, KRAS, p53, NF-kB, TGF-ß, and MGMT in the esophageal tissue were analyzed and compared between the four groups. In normal esophageal tissue, selenium supplementations (2, 10, and 20 mg Se/L) increased the mRNA levels of cyclin D1, P53, KRAS, NF-κB p65, and MGMT and decreased the mRNA level of TGFß1. The concentrations of cyclin D1 and MGMT were also significantly increased by selenium supplementations. Selenium supplementations had no significant effect on serum MDA but significantly increased GPX activity. The present study suggests that selenium supplementation (2, 10, and 20 mg Se/L) affects gene expression related to inflammation, Cell proliferation, and apoptosis in the normal esophageal tissue. However, there were no observed abnormalities other than reduced growth with supplementation of 20 mg/L as Na2SeO3 in rats.

Selenium Effects on Oxidative Stress-Induced Calcium Signaling Pathways in Parkinson's Disease.

Parkinson's disease (PD) is a neurological disorder in which oxidative stress and reactive oxygen species productions are proposed to be involved in its pathogenesis. Despite considerable advancement in Selenium's (Se) molecular biology and metabolism, we do not know much about the cell type-specific pattern of Se distribution in the brain of PD humans and experimental animals. Although, there is plenty of evidence around the role of Se deficiency in PD's pathogenesis impacting lipid peroxidation and reducing glutathione (GSH) and glutathione peroxidase (GPX). It has been suggested that Se has an inducible role in selenium-dependent GPX activity in PD animals and humans. However, calcium as a second messenger regulates the neuron cells' essential activities, but its overloading leads to cellular oxidative stress and apoptosis. Therefore, Se's antioxidant role can affect calcium signaling and alleviate its complications. There are signs of Se and Selenoproteins incorporation in protecting stress oxidative in various pathways. In conclusion, there is convincing proof for the crucial role of Se and Calcium in PD pathogenesis. Supplementary Information: The online version contains supplementary material available at 10.1007/s12291-022-01031-1.

Decreased Serum Selenium Levels of COVID-19 Patients in Comparison with Healthy Individuals.

BACKGROUND: Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) is the cause of the COVID-19 pandemic and is the cause of increased mortality, especially among elderly patients and those who have severe complications, such as chronic pulmonary obstruction, hypertension, diabetes, and cancer. Nutrition, especially micronutrients, plays an important role in reducing mortality and complications from COVID-19 because micronutrients strengthen our immune system and nutritional status is an important factor that affects the outcome of patients with COVID-19. Among micronutrients, selenium has an important effect on both intrinsic and acquired immunity. Host selenium deficiency affects the viral genome and increases the virulence of viruses. We have investigated the serum selenium levels in COVID-19 patients and healthy control individuals. METHODS: A total of 50 patients with COVID-19 infection were included in this study. During hospitalization, 13 patients died (non-survivor group) and 37 patients recovered (survivor group). We assessed the serum selenium levels in 50 COVID-19 patients and 50 healthy individuals by Agilent SpectrAA-240 Z atomic absorption spectrometer. RESULTS: The serum selenium level was significantly lower in COVID-19 patients (77. 8 ± 13.9 µg/L) as compared to healthy control individuals (91.7 ± 16.7 µg/L), but there was no significant difference between the survivor and non-survivor groups. Also, there was no significant relationship between serum selenium levels and laboratory findings of COVID-19 patients. CONCLUSIONS: These results suggest that decreased serum selenium levels may be a risk factor for the COVID-19 infection, but there was no significant relationship between selenium and severity and mortality of COVID-19 disease.

comparison of the Serum Levels of Trace Elements in Areas with High or Low Rate of Esophageal Cancer.

BACKGROUND There is a critical role for trace elements in cancer prevention. Since northeast Iran is known as a high risk area for esophageal cancer, this study was designed to compare the serum levels of some trace elements in high and low rate areas of Golestan province. METHODS We used 240 fasting serum samples obtained in 2011 from eastern and western parts of Golestan province during the non-communicable diseases' screening program. To carry out laboratory examinations, the samples were firstly deproteinated and then the concentrations of the intended elements were measured by an atomic absorption spectrometer. A total of 227 samples were used in the present study and the remaining 13 samples were excluded due to inappropriate conditions. RESULTS The mean serum level of zinc in the high-risk region was significantly lower than that in the low-risk region. But no significant difference was detected in serum levels of copper, magnesium, and manganese in the low-risk and high-risk regions. CONCLUSION As this study was an ecological study with no comparison between patients with cancer and healthy population, its results cannot be used for the general population. Therefore, complementary studies including case-control studies are suggested for further evaluation of the relationship between these elements and the incidence of esophageal cancer.

Selenium levels in rice samples from high and low risk areas for esophageal cancer.

OBJECTIVE: To assess the relationship between selenium (Se) concentration in rice and the incidence of esophageal cancer (EC) in a high risk area in Northern Iran. METHODS: This ecological study was conducted in Golestan province of Iran in 2012. In this area, 45714 acres of land are cultivated by rice. A total of 69 rice samples were taken. We investigated Se concentrations by the voltammetric method. Statistical analysis was performed using the Pearson correlation test and Mann-Whitney U test. RESULTS: The mean (+/-SD) Se level in rice samples was 0.229 (+/-0.145) mg/kg. The Se concentration was significantly higher in rice samples from high EC rate areas (0.35 mg/kg) compared with low risk areas (0.16 mg/kg) (p<0.001). There was a significant positive correlation between the levels of Se in rice and the incidence rate of EC (p=0.03). CONCLUSION: We found a high rice Se concentration and a significant positive relationship between rice Se levels and EC rates in the Golestan province of Iran. High soil and rice Se levels may play a possible role in the pathogenesis of EC in this area.

Effects of omeprazole consumption on serum levels of trace elements.

PROJECT: Omeprazole is one of the most frequently prescribed drugs in patients with gastroesophageal reflux disease (GERD). It increases the gastric pH and this in turn may change the intestinal absorption of trace elements. This study was conducted to assess the effects of omeprazole consumption on the serum level of trace elements. PROCEDURES: The studied subjects were selected from the list of patients referred to the gastroenterology department of 5 Azar hospital in Golestan province of Iran for whom omeprazole was prescribed by a gastroenterologist. Blood samples were obtained before (phase I) and after an eight-week period (phase II) of omeprazole consumption. Serum levels of trace elements were assessed by the photometric method. RESULTS: Sixty seven patients were recruited of whom, 35.82% were males. There was no significant difference in serum levels of Fe, P, Ca and Cu between phases I and II. Serum concentration of Zn was significantly lower in phase II than I (P=0.02). The proportion of male patients with low Zn levels was significantly higher in phase II (50%) than I (16.7%) (P=0.01). We found no significant difference in the proportion of female patients with low Zn levels between phase I (37.2%) and phase II (27.9%). CONCLUSIONS: We found no significant reduction in serum levels of Fe, P, Ca and Cu in phase II. However, our results showed that serum level of Zn was significantly lower after omeprazole consumption in males. So, nutritional supplement of Zn should be considered in male patients treated with omeprazole.

Effects of Vitamin E and Zinc Supplementation on Antioxidants in Beta thalassemia major Patients.

OBJECTIVE: In beta thalassemic patients, tissue damage occurs due to oxidative stress and it happens because of the accumulation of iron in the body. This study was conducted to determine the effect of zinc and vitamin E supplementation on antioxidant status in beta-thalassemic major patients. METHODS: This double blind randomized clinical trial was carried out on 120 beta thalassemic patients older than 18 years. Patients were randomly categorized in four groups. Zinc (50mg/day) and vitamin E (400mg/day) supplements were administered for former and latter group, respectively. In the third group both supplements were administered in similar doses. The fourth (control) group received no supplement. The effect of supplementations on serum zinc and vitamin E, superoxide dismutase (SOD), glutathione peroxidase (GPX), total antioxidant capacity (TAC) and body mass index (BMI) were measured at the beginning and the end of the study. FINDINGS: Serum zinc levels in group 1 and 3 were significantly increased (P<0.007 and P<0.005, respectively). Serum vitamin E levels in group 2 and 3 were also increased significantly (P<0.001). Mean GPX activity in group1, 2 and 3 decreased significantly (P<0.015, P<0.032 and P<0.029, respectively). Mean SOD activity and TAC did not show significant change after supplementation. BMI had significant increase in all treated groups (P<0.001). CONCLUSION: Our results suggest that beta thalassemic patients have enhanced oxidative stress and administration of selective antioxidants may preclude oxidative damage.