Selenium Homeostasis and Clustering of Cardiovascular Risk Factors: A Systematic Review

A comprehensive review on recent advancements in drug delivery via selenium nanoparticles

Nanotechnology has significantly impacted drug discovery and development over the past three decades, offering novel insights and expanded treatment options. Key to this field is nanoparticles, ranging from 1 to 100 nanometres, with unique properties distinct from larger materials. Selenium nanoparticles (SeNPs) are particularly promising due to their low toxicity and selective cytotoxicity against cancer cells. They have shown efficacy in reducing various cancers types and mitigating conditions like diabetic nephropathy and neurological disorders, such as Alzheimer's disease. This review highlights SeNPs' role in enhancing drug delivery systems, improving the absorption of water-soluble compounds, proteins, peptides, vaccines, and other biological therapies. By modifying nanoparticle surfaces with targeting ligands, drug delivery can achieve precise site-specific delivery, increasing effectiveness. SeNPs can be synthesised through physical, chemical, and biological methods, each offering advantages in stability, size, and application potential. Additionally, SeNPs enhance immune responses and reduce oxidative stress, validating their role in biotherapy and nanomedicine. Their ability to target macrophages and regulate polarisation underscores their potential in antimicrobial therapies. Recent advancements, such as mannosylated SeNPs for targeted delivery, exemplify innovative nanotechnology applications in medicine. Overall, SeNPs represent a promising frontier in nanomedicine, offering new avenues for treating and managing various diseases.

Association Between Serum Selenium Concentration and OPG/RANKL/RANK Axis in Patients with Arterial Hypertension

The aim of the study was to determine the relationship between the serum selenium concentration (Se-S) and the blood concentrations of osteoprotegerin (OPG), receptor activator of nuclear factor kappa-Β ligand (RANKL) and the OPG/RANKL ratio in patients with arterial hypertension. The study group comprised 138 patients with arterial hypertension (age: 56.04 ± 11.59 years). Se-S was determined in all the subjects. Based on the Se-S, the following subgroups were distinguished: a subgroup of patients with a lower Se-S ("low-Se", Se-S < median) and a subgroup of patients with a higher Se-S ("high-Se", Se-S ≥ median). Moreover, the blood concentrations of the parameters of bone metabolism and extraskeletal calcification were assessed: OPG and RANKL. The OPG/RANKL ratio was calculated. In the "low-Se" subgroup, the RANKL concentration was statistically significantly lower, and the OPG/RANKL ratio was statistically significantly higher than in the patients in the "high-Se" subgroup. The correlation analysis showed the negative linear relationships between Se-S and OPG (r = - 0.25, p < 0.05) and between Se-S and OPG/RANKL (r = - 0.47, p < 0.05). Moreover, Se-S positively correlated with RANKL (r = 0.33, p < 0.05). In regression analysis, higher body mass index (BMI), smoking and lower Se-S were independently associated with a higher OPG/RANKL ratio, while lower BMI, use of diuretics, β-blockers and ACE inhibitors and lower OPG/RANKL ratio with effective blood pressure control. In summary, in the group of patients with arterial hypertension, lower Se-S is associated with an unfavourable prognostic panel of parameters of bone metabolism and extraskeletal calcification. Lower Se-S is an independent risk factor for a higher OPG/RANKL ratio, which is an independent prediction factor of ineffective blood pressure control in patients with hypertension.

A Comprehensive Review on Selenium and Its Effects on Human Health and Distribution in Middle Eastern Countries

Selenium (Se) is an important microelement with numerous positive effects on human health and diseases. It is important to specify that the status and consumption of Se are for a specific community as the levels of Se are extremely unpredictable between different populations and regions. Our existing paper was based on the impacts of Se on human health and disease along with data on the Se levels in Middle Eastern countries. Overall, the findings of this comprehensive review show that the consumption and levels of Se are inadequate in Middle Eastern nations. Such findings, together with the growing awareness of the importance of Se to general health, require further work primarily on creating an acceptable range of blood Se concentration or other measures to determine optimal Se consumption and, consequently, to guarantee adequate Se supplementation in populations at high risk of low Se intake.

Cysteine-Activated Small-Molecule H2Se Donors Inspired by Synthetic H2S Donors

The importance of selenium (Se) in biology and health has become increasingly clear. Hydrogen selenide (H₂Se), the biologically available and active form of Se, is suggested to be an emerging nitric oxide (NO)-like signaling molecule. Nevertheless, the research on H₂Se chemical biology has technique difficulties due to the lack of well-characterized and controllable H₂Se donors under physiological conditions, as well as a robust assay for direct H₂Se quantification. Motivated by these needs, here, we demonstrate that selenocyclopropenones and selenoamides are tunable donor motifs that release H₂Se upon reaction with cysteine (Cys) at pH 7.4 and that structural modifications enable the rate of Cys-mediated H₂Se release to be tuned. We monitored the reaction pathways for the H₂Se release and confirmed H₂Se generation qualitatively using different methods. We further developed a quantitative assay for direct H₂Se trapping and quantitation in an aqueous solution, which should also be operative for investigating future H₂Se donor motifs. In addition, we demonstrate that arylselenoamide has the capability of Cys-mediated H₂Se release in cellular environments. Importantly, mechanistic investigations and density functional theory (DFT) calculations illustrate the plausible pathways of Cys-activated H₂Se release from arylselenoamides in detail, which may help understand the mechanistic issues of the H₂S release from pharmacologically important arylthioamides. We anticipate that the well-defined chemistries of Cys-activated H₂Se donor motifs will be useful for studying Se biology and for development of new H₂Se donors and bioconjugate techniques.

A Nonlinear Relation Between Maternal Red Blood Cell Manganese Concentrations and Child Blood Pressure at Age 6-12 y: A Prospective Birth Cohort Study

BACKGROUND

Although manganese (Mn) is an essential trace element and a common component of most multivitamins on the market, an adverse effect on blood pressure (BP) has been reported in adults. In addition, the longitudinal relation between prenatal Mn status and childhood BP is still unknown.

OBJECTIVE

This study investigated the association between prenatal Mn concentrations and risk of elevated BP at ages 3-12 y.

METHOD

The analyses included 1268 mother-child dyads who were enrolled at birth and followed prospectively at the Boston Medical Center. Maternal RBC Mn concentrations were measured by inductively coupled plasma mass spectrometry, using RBCs collected within 1-3 d after delivery (reflecting late-pregnancy Mn exposure). Child elevated BP was defined as systolic or diastolic BP ≥90th percentile for a given age, sex and height. Multivariate logistic regression models were conducted. Path analysis was applied to mediation estimation.

RESULTS

The median (IQR) maternal RBC Mn concentration was 37.5 (29.2-48.5) μg/L. The rate of child elevated BP at ages 3-12 y was 25%. Both the lowest and highest quartiles of maternal RBC Mn concentrations were associated with higher risk of elevated BP among children aged 6-12 y (OR: 1.52; 95% CI: 1.04, 2.21 and OR: 1.65; 95% CI: 1.13, 2.40, respectively) compared with those in the second and third quartiles. Gestational age and fetal growth mediated the association between low maternal RBC Mn (first quartile) and child elevated BP, explaining 25% of the association, but not for high (fourth quartile) maternal RBC Mn concentrations. No association was found between maternal RBC Mn concentrations and BP among children aged 3-5 y.

CONCLUSION

We found a nonlinear association between maternal RBC Mn concentrations and elevated BP among children aged 6-12 y from a high-risk, predominantly minority population. Our findings warrant further investigation.

Selenium and hydrogen selenide: essential micronutrient and the fourth gasotransmitter?

Selenium (Se) is an essential micronutrient required by organisms of diverse lineage. Dietary Se is converted to hydrogen selenide either enzymatically or by endogenous antioxidant proteins. This convergent biochemical step crucially underlies the subsequent biological activity of Se and argues for inclusion of hydrogen selenide as the fourth endogenous gasotransmitter alongside nitric oxide, carbon monoxide and hydrogen sulfide.Endogenously generated hydrogen selenide is incorporated into numerous 'selenoprotein' oxidoreductase enzymes, essential for maintaining redox-status homeostasis in health and disease. Direct effects of endogenous hydrogen selenide on cellular and molecular targets are currently unknown. Given exogenously, hydrogen selenide acts as a modulator of metabolism via transient inhibition of mitochondrial cytochrome C oxidase. Here we provide an overview of Se biology, its impact on several physiological systems (immune, endocrine, cardiovascular and metabolic) and its utility as a supplement in acute and critical illness states. We further explore the evidence base supporting its role as the fourth gasotransmitter and propose a strategic case towards generation of novel selenomimetic therapeutics.

Selenium Biofortification of Agricultural Crops and Effects on Plant Nutrients and Bioactive Compounds Important for Human Health and Disease Prevention - a Review

Selenium supplementation in humans has been suggested for the prevention of chronic diseases including cardiovascular disease, cancer, and neurodegenerative diseases. Selenium biofortification of plants has been explored as a method for increasing selenium content of food and dietary selenium intake in humans. However, the effects of selenium biofortification on other dietary nutrients is often a secondary discussion. These effects are especially important to explore considering selenium-biofortified foods contain many other nutrients important to human health, such as other minerals and antioxidant compounds, which can make these foods superior to selenium supplementation alone. Investigation of selenium biofortification's effect on these nutrients is necessary for a comprehensive human nutrition perspective on biofortification strategies. This review considers the effects of selenium biofortification on selenium content, other minerals, and antioxidant compounds as they pertain to human health in order to suggest optimal strategies for biofortification. Pre-clinical and clinical studies assessing the effects of consumption of selenium biofortified foods are also discussed.

Effects of selenium supplementation on paraoxonase-1 and myeloperoxidase activity in subjects with cardiovascular disease: the Selenegene study, a double-blind randomized controlled trial

Introduction

We previously highlighted the potential link between supplementation with selenium, as an antioxidant trace element, and changes in the levels of paraoxonase (POX1) and myeloperoxidase (MPO), as an antioxidant enzyme, in patients with documented cardiovascular disease (CVD). The aim of this study was to determine the effects of selenium supplementation on POX1 and MPO activity in patients with cardiovascular diseases (CVDs).

Material and methods

A total of 160 eligible patients were enrolled in the study. After performing some laboratory tests, including the measurement of blood selenium, triglyceride, cholesterol, and low- and high-density lipoprotein levels, the patients received 200 mg tablets of either selenium yeast or placebo. The medicines were taken orally, once daily after a meal for 60 days. Four weeks after the initial visit, the patients were invited for a follow-up visit, and interviews and non-laboratory evaluations, similar to those performed at baseline, were repeated. Compliance of patients for using selenium and placebo was measured by telephone. Medication compliance rates were monitored by telephone. The final assessments were conducted eight weeks after the beginning of the study.

Results

There was no significant difference in cholesterol levels between intervention and control groups (p = 0.87). No significant changes in selenium levels were observed in either the selenium or the placebo group after the intervention (p = 0.44 and p = 0.48, respectively). The two groups had a significant difference in terms of POX1 level (p = 0.039). No such difference was present in the case of MPO levels. Moreover, comparison of the values before and after the intervention showed no significant differences in the mean levels of any of the measured parameters.

Conclusions

According to the obtained results, the increased POX1 levels after selenium supplementation could be attributed to the positive effect of selenium on inhibiting lipid peroxidation as part of the complicated pathophysiology of CVD.

Selenium as a pleiotropic agent for medical discovery and drug delivery

Selenium as a biologically active element lends much support to health maintenance and disease prevention. It is now presenting pleiotropic effects on therapy and drug delivery. In this study, a profiling on the physiological functions, therapeutic significances, clinical/preclinical performances, and biomedical and drug delivery applications of selenium in different modalities was carried out. Major interests focused on selenium-based nanomedicines in confronting various diseases pertaining to selenium or not, especially in antitumor and antidiabetes. Furthermore, the article exclusively discusses selenium nanoparticles featured by ameliorative functions with emphasis on their applications in medical practice and drug delivery. The state-of-the-art in medical discovery as well as research and development on selenium and nano-selenium is discussed in this review.