Plasma selenium and the risk of first stroke in adults with hypertension: a secondary analysis of the China Stroke Primary Prevention Trial

Quantitatively Tracking the Speciation and Dynamics of Selenium Nanoparticles in Rice Plants

The uptake, translocation, and transformation of engineered nanoparticles (ENPs) in plants present significant challenges due to the lack of effective determination methods. This is especially true for selenium nanoparticles (SeNPs), which hold promise for Se-biofortified agriculture and exhibit dynamic behaviors within plant system. Herein, we proposed a novel approach that incorporates enzymic digestion and membrane filtration to selectively extract SeNPs and dissolved Se from plant tissues, employing rice (Oryza sativa) plant as a model. Subsequently, the SeNPs retained on the membrane were quantified using inductively coupled plasma mass spectrometry (ICPMS), while the dissolved Se in the filtrate, including selenite (Se(IV)), selenate (Se(VI)), and seleno amino acid, were analyzed by liquid chromatography coupled with ICPMS (LC-ICPMS). Recoveries of 83.5-91.4% for SeNPs and 73.6-99.4% for dissolved Se at a spiking level of 8 μg/g in quality control samples were obtained. With the established method, it was discovered that SeNPs taken up by rice leaves can transform into Se (IV) and organic Se, and all the Se species could be translocated downward, but only Se (IV) and SeNPs could be excreted through the roots. These findings provide valuable insights into the fate of SeNPs in plants and their related biological responses.

The role of glutathione peroxidase 4 in neuronal ferroptosis and its therapeutic potential in ischemic and hemorrhagic stroke

Ferroptosis is a type of cell death that depends on iron and is driven by lipid peroxidation, playing a crucial role in neuronal death during stroke. A central element in this process is the inactivation of glutathione peroxidase 4 (GPx4), an antioxidant enzyme that helps maintain redox balance by reducing lipid hydroperoxides. This review examines the critical function of GPx4 in controlling neuronal ferroptosis following ischemic and hemorrhagic stroke. We explore the mechanisms through which GPx4 becomes inactivated in various stroke subtypes. In strokes, excess glutamate depletes glutathione (GSH) and products of hemoglobin breakdown overwhelm GPx4. Studies using genetic models with GPx4 deficiency underscore its vital role in maintaining neuronal survival and function. We also consider new therapeutic approaches to enhance GPx4 activity, including novel small molecule activators, adjustments in GSH metabolism, and selenium supplementation. Additionally, we outline the potential benefits of combining these GPx4-focused strategies with other anti-ferroptotic methods like iron chelation and lipoxygenase inhibition for enhanced neuroprotection. Furthermore, we highlight the significance of understanding the timing of GPx4 inactivation during stroke progression to design effective therapeutic interventions.

Selenium, diabetes, and their intricate sex-specific relationship

Selenium (Se) is an essential trace element, which is inserted as selenocysteine (Sec) into selenoproteins during biosynthesis, orchestrating their expression and activity. Se is associated with both beneficial and detrimental health effects; deficient supply or uncontrolled supplementation raises concerns. In particular, Se was associated with an increased incidence of type 2 diabetes (T2D) in a secondary analysis of a randomized controlled trial (RCT). In this review, we discuss the intricate relationship between Se and diabetes and the limitations of the available clinical and experimental studies. Recent evidence points to sexual dimorphism and an association of Se deficiency with gestational diabetes mellitus (GDM). We highlight the emerging evidence linking high Se status with improved prognosis in patients with T2D and lower risk of macrovascular complications.

Deciphering the associations of selenium distribution in serum GPx-3 and selenoprotein P with cardiovascular risk factors in a healthy population with moderate levels of selenium: The ATTICA study

BACKGROUND

Selenium (Se) is an essential micronutrient, important for human health. The relationship of Se with cardiovascular risk factors is still inconclusive, especially regarding the role of different selenoproteins. The present study evaluated the relation of total serum Se as well as its distribution in plasma selenoproteins, namely glutathione peroxidase 3 (GPx3) and selenoprotein P (SelP) with cardiovascular risk factors in a sex-specific manner, in a healthy population with moderate levels of Se.

METHODS

A sub-sample from the ATTICA Study's database, consisting of 398 participants (160 females and 238 males) with data on Se and selenoproteins levels, was considered. GPx3, SelP and the main non-specific serum selenium containing protein, selenoalbumin (SeAlb) were simultaneously determined in human plasma by high-performance liquid chromatography (HPLC) coupled with inductively coupled plasma mass spectrometry (ICP-MS) at baseline.

RESULTS

Participants that belong to the highest tertiles of GPx3 and SelP presented the lowest blood pressure. Homocysteine was inversely associated with SelP and its ratio SelP/TSe in both sexes. In males, the lowest tertile of GPx3 showed lower adiponectin levels (0.66 ± 0.21 μg/mL) in comparison to the 2nd tertile of GPx3 (p=0.002), SelP was inversely associated with visceral adipose index (VAI) (-2.29 ± 0.81, p=0.005). Particularly, in males, the middle tertile of SelP had the lowest VAI values. Regarding females, lower Lp(a) concentration by 11.96 ± 5.84 mg/dL was observed in low SelP levels while higher leptin concentration by 2.30 ± 0.73 μg/L and lower fibrinogen concentration by 27.32 ± 13.30 mg/dL was detected in low GPx3 levels.

CONCLUSION

Circulating selenoproteins exert differentiated effects on cardiovascular risk factors, some of them in a sex-specific manner.

Se-(Methyl)-selenocysteine ameliorates blood-brain barrier disruption of focal cerebral ischemia mice via ferroptosis inhibition and tight junction upregulation in an Akt/GSK3β-dependent manner

BACKGROUND

Ischemic stroke still ranks as the most fatal disease worldwide. Blood-brain barrier (BBB) is a promising therapeutic target for protection. Brain microvascular endothelial cell is a core component of BBB, the barrier function maintenance of which can ameliorate ischemic injury and improve neurological deficit. Se-methyl L-selenocysteine (SeMC) has been shown to exert cardiovascular protection. However, the protection of SeMC against ischemic stroke remains to be elucidated. This research was designed to explore the protection of SeMC from the perspective of BBB protection.

METHODS

To simulate cerebral ischemic injury, C57BL/6J mice were subjected to middle cerebral artery occlusion/reperfusion (MCAO/R), and bEnd.3 was exposed to oxygen-glucose deprivation/reoxygenation (OGD/R). After the intervention of SeMC, the barrier function and the expression of tight junction and ferroptosis-associated proteins were determined. For mechanism exploration, LY294002 (Akt inhibitor) was introduced both in vivo and in vitro.

RESULTS

SeMC lessened the brain infarct volume and attenuated the leakage of BBB in mice. In vitro, SeMC improved cell viability and maintained the barrier function of bEnd.3 cells. The protection of SeMC was accompanied with ferroptosis inhibition and tight junction protein upregulation. Mechanism studies revealed that the effect of SeMC was reversed by LY294002, indicating that the protection of SeMC against ischemic stroke was mediated by the Akt signal pathway.

CONCLUSION

These results suggested that SeMC exerted protection against ischemic stroke, which might be attributed to activating the Akt/GSK3β signaling pathway and increasing the nuclear translocation of Nrf2 and β-catenin, subsequently maintaining the integrity of BBB.

The non-linear link between non-high-density lipoprotein to high-density lipoprotein ratio and the risk of stroke in middle-aged and older adults in Chinese: a prospective cohort study from the China health and retirement longitudinal study

Objective

This study aims to assess the association between the non-HDL-c/HDL-c ratio and stroke risk among middle-aged and older adults participating in the China Health and Retirement Longitudinal Study (CHARLS).

Methods

This study conducted a prospective cohort analysis, enrolling a total of 10,183 participants who met the designated criteria from CHARLS between 2011 and 2012. We then used the Cox proportional-hazards regression model to explore the relationship between baseline non-HDL-c/HDL-c ratio and stroke risk. Using a Cox proportional hazards regression with cubic spline function, we were able to identify the non-linear relationship between the non-HDL-c/HDL-c ratio and stroke occurrence. A series of sensitivity analyses were also carried out.

Results

The average age of the participants included in this study was 59.16 ± 9.35 years, and 4,735 individuals (46.68%) were male. Over a median follow-up period of 7.0 years, a total of 1,191 people (11.70%) experienced a stroke. Using a Cox proportional hazards regression model that was fully adjusted, we found no statistically significant correlation between the non-HDL-c/HDL-c ratio and the risk of stroke (HR=1.022; 95% CI 0.964, 1.083). Nevertheless, we did observe a non-linear relationship and saturation effect between the non-HDL-c/HDL-c ratio and stroke. Employing a two-piece Cox proportional hazards regression model and a recursive algorithm, we determined an inflection point of 2.685 for the non-HDL-c/HDL-c ratio. In instances where the non-HDL-c/HDL-c ratio fell below 2.685, for every 1-unit decrease in the non-HDL-c/HDL-c ratio, the likelihood of stroke decreased by 21.4% (HR=1.214, 95% CI: 1.039-1.418). In contrast, when the non-HDL-c/HDL-c ratio exceeded 2.685, there was no statistically significant change in the risk of stroke for each unit decrease in the non-HDL-c/HDL-c ratio (HR: 0.967, 95% CI: 0.897-1.042). The consistency of these findings across multiple sensitivity analyses suggests their robustness.

Conclusion

This study unveils a non-linear relationship between the non-HDL-c/HDL-c ratio and stroke risk in middle-aged and older adults in China. Specifically, when the non-HDL-c/HDL-c ratio was below 2.685, a significant and clearly positive association with stroke risk was observed. Additionally, maintaining the non-HDL-c/HDL-c ratio below 2.685 could potentially lead to a substantial reduction in the risk of stroke.

Selenium's Role in Neuroprotection Against Stroke-Induced Inflammation

Acute ischemic stroke (AIS) incidence across the globe is on the rise, and the deleterious effects have not yet been improved with the use of current pharmaceuticals. Tissue plasminogen activator (tPA) has many risks and time constraints, making it difficult to use even as the standard treatment. Selenium deficiency and stroke incidence have a strong linear correlation among various populations. Using the ADME-Tox software, selenious acid absorption in brain cells, tissue, and interstitium was modeled under ischemic conditions to determine the bioavailability of selenium (Se) in the brain using various IV (intravenous) infusion doses. Additionally, we studied the cytotoxicity of selenious acid and selenourea on human dermal fibroblasts (HDF) and lung carcinoma cells (A549) to determine the overall growth and toxicity of different body cell lines to account for systemic side effects of IV infusion. Our data suggest that selenium can reach a dose-dependent concentration of 1.5µg/L or 250µg/L in brain cells within two hours of a one-time IV infusion, showing the ability to reach brain vasculature. Furthermore, cell viability can be maintained between 95% and 100% using 1nM and 0.5nM concentrations of selenious acid.

Increased hypertension risk for the elderly with high blood levels of strontium and lead

Hypertension has long been recognized as the global health burden. Heavy metal pollution may be one of the environmental risk factors of hypertension. However, the association remains unclear. We studied the levels of aluminum (Al), vanadium (V), manganese (Mn), arsenic (As), selenium (Se), strontium (Sr), barium (Ba), titanium (Ti), lead (Pb) and cobalt (Co) in whole blood, and the relationship between trace element exposure and hypertension in the elderly community-based Chinese population. A total of 1013 participants from the west of Anhui Province in China were consecutively enrolled in this study in 2016. The general sociodemographic characteristics, lifestyles, disease history and physical examination information were collected by face-to-face survey and physical examination. The levels of ten trace elements were determined by inductively coupled plasma mass spectrometry (ICP-MS). Multivariable logistic regression model was used to assess the association of trace element exposure with the risk of hypertension. Results showed that the odds ratio of hypertension in the highest quartile was 1.811 (95% CI 1.175-2.790, P trend = 0.005) and 1.772 (95% CI 1.121-2.800, P trend = 0.022), respectively, after adjusting for potential confounders, as compared with the lowest quartile of blood Pb and Sr levels.

Association of habitually low intake of dietary selenium with new-onset stroke: A retrospective cohort study (2004-2015 China Health and Nutrition Survey)

Background

As an essential trace element in the body, selenium is associated with the development of many diseases. The purpose of this study was to explore the association between dietary selenium intake and new-onset stroke risk in Chinese adults.

Methods

Adults aged ≥18 years in the China Health and Nutrition Survey (CHNS) from 2004 to 2015 were enrolled. Participants were divided into five groups according to the quintile of dietary selenium intake: Q1 (≤ 29.80 μg/day), Q2 (29.80-38.53 μg/day), Q3 (38.53-47.23 μg/day), Q4 (47.23-60.38 μg/day), Q 5(>60.38 μg/day). Cox proportional-hazards model was used to explore the effect of dietary selenium on new-onset stroke. Restricted cubic spline (RCS) was used to visualize the dose-response relationship between dietary selenium and the risk of morbidity.

Results

A total of 11,532 subjects were included, and 271 (2.35%) of them developed stroke during a mean follow-up of 6.78 person-years. Compared with the lowest selenium intake group, the HR and 95%CI of stroke in the participants with selenium intake of Q2, Q3, Q4 and Q5 were: 0.85 (0.59, 1.21), 0.62 (0.42, 0.92), 0.43 (0.28, 0.68), 0.49 (0.30, 0.82), respectively. There was an L-shaped relationship between dietary selenium and stroke (nonlinear P-value = 0.0420). The HR and 95%CI of developing stroke was 0.75 (0.65, 0.87) in participants with selenium intake ≤ 60 μg/day.

Conclusions

The L-shaped negative association between dietary selenium and stroke in Chinese adults which indicated that dietary selenium should be improved to a certain level to prevent stroke.

Association between plasma selenium and risk of ischemic stroke: A community-based, nested, and case-control study

Background

The prospective association between plasma Se and stroke risk remains inconclusive. The relationship between Se and ischemic stroke among a low circulating Se status population deserves more attention, especially for Chinese people who were a high-risk group for Se deficiency.

Objective

The relationship between plasma Se concentration and ischemic stroke risk in a large-scale Chinese community-based population and any potential effect modifiers were investigated.

Methods

A nested, case-control study, using data from the “China H-type Hypertension Registry Study” were conducted. A total of 1,904 first ischemic stroke cases and 1,904 controls matched for age, sex, and village were included in this study. The association between plasma Se and first ischemic stroke was evaluated by conditional logistic regression analyses.

Results

The median value of plasma Se was 65.8 μg/L among total participants. Overall, a significant inverse relationship between plasma Se and first ischemic stroke risk was found (per SD increment; adjusted OR: 0.87; 95% CI: 0.80 and 0.95). Accordingly, a significantly lower risk of first ischemic stroke was found in participants in quartile 3 (65.8−<77.8 μg/L) (adjusted OR: 0.78; 95% CI: 0.63 and 0.96) and quartile 4 (≥77.8 μg/L) (adjusted OR: 0.76; 95% CI: 0.59 and 0.96), compared with those in quartile 1 (<56.0 μg/L). Furthermore, a significantly lower ischemic stroke risk was found in those with lower low-density lipoprotein cholesterol (LDL-C) levels (<3.4 vs. ≥3.4 mmol/L; P for interaction = 0.015) or those with lower homocysteine levels (<12.1 (median) vs. ≥12.1 μmol/L; P for interaction = 0.027) at baseline.

Conclusion

Plasma Se was significantly inversely associated with the risk of first ischemic stroke among a large-scale Chinese community-based population (most adults with hypertension and elevated total homocysteine), especially among those with lower LDL-C and lower homocysteine levels.

Vegan nutrition: a preliminary guide for health professionals

Since the beginning of the 21st century, interest in vegan diets has been rapidly increasing in most countries. Misconceptions about vegan diets are widespread among the general population and health professionals. Vegan diets can be health-promoting and may offer certain important advantages compared to typical Western (and other mainstream) eating patterns. However, adequate dietary sources/supplements of nutrients of focus specific to vegan diets should be identified and communicated. Without supplements/fortified foods, severe vitamin B12 deficiency may occur. Other potential nutrients of focus are calcium, vitamin D, iodine, omega-3 fatty acids, iron, zinc, selenium, vitamin A, and protein. Ensuring adequate nutrient status is particularly important during pregnancy, lactation, infancy, and childhood. Health professionals are often expected to be able to provide advice on the topic of vegan nutrition, but a precise and practical vegan nutrition guide for health professionals is lacking. Consequently, it is important and urgent to provide such a set of dietary recommendations. It is the aim of this article to provide vegan nutrition guidelines, based on current evidence, which can easily be communicated to vegan patients/clients, with the goal of ensuring adequate nutrient status in vegans.

Selenium Status and Its Antioxidant Role in Metabolic Diseases

Selenium (Se), in the form of selenoproteins, is an essential micronutrient that plays an important role in human health and disease. To date, there are at least 25 selenoproteins in humans involved in a wide variety of biological functions, including mammalian development, metabolic progress, inflammation response, chemoprotective properties, and most notably, oxidoreductase functions. In recent years, numerous studies have reported that low Se levels are associated with increased risk, poor outcome, and mortality of metabolic disorders, mainly related to the limited antioxidant defense resulting from Se deficiency. Moreover, the correlation between Se deficiency and Keshan disease has received considerable attention. Therefore, Se supplementation as a therapeutic strategy for preventing the occurrence, delaying the progression, and alleviating the outcomes of some diseases has been widely studied. However, supranutritional levels of serum Se may have adverse effects, including Se poisoning. This review evaluates the correlation between Se status and human health, with particular emphasis on the antioxidant benefits of Se in metabolic disorders, shedding light on clinical treatment.

A Cross-Sectional Study of the Distribution Patterns and Potential Determinants in Plasma Selenium Status Among Chinese Adults With Hypertension

Selenium (Se) is an essential trace element in selenoproteins biosynthesis for the human body and plays an important role in the prevention and control of subsequent cardiovascular disease in adults with hypertension. However, reports on Se status and its potential determinants in populations from different regions of China are limited, especially data on adults with hypertension, a high-risk group more vulnerable to oxidative stress. Thus, we conducted a cross-sectional study from February 2017 to May 2018 of 2,599 participants (1,389 men and 1,210 women) on middle-aged to elderly adults with hypertension with a mean age of 63.1 years (SD 13.3) from 14 provinces of China and aimed to examine the relationship of plasma Se status with demographic characteristics and lifestyles. Overall, the male participants (mean value 75.0 μg/L) tended to have higher plasma Se concentrations than the female participants (73.7 μg/L) when controlling for relevant factors. There were significant differences among regions, and in age and body mass index (BMI) in plasma Se distribution, and plasma Se concentrations were significantly lower among those in the regions with relatively lower Se, aged 60 years or older, and with BMI lower than 28 kg/m². Moreover, a higher frequency of meat consumption (1-2 or ≥3 times/week vs. <1 time/week) was significantly associated with higher plasma Se concentrations in men and women, and male alcohol drinkers had significantly higher plasma Se concentrations than non-alcohol drinkers. Adequate consumption of fruits and vegetables (0.5-1.5 kg/week) was associated with higher plasma Se concentrations among women, but was associated with relatively lower plasma Se concentrations in men. Our results indicated relatively low plasma Se status in Chinese adults with hypertension from 14 provinces, while specific factors including geographic, demographic, and lifestyle characteristics and blood pressure were significantly associated with plasma Se status in this hypertensive population. In addition, more studies are required to further evaluate dietary structure and other lifestyle factors that influence circulating Se status.

Biofortified Maize Improves Selenium Status of Women and Children in a Rural Community in Malawi: Results of the Addressing Hidden Hunger With Agronomy Randomized Controlled Trial

Background: Selenium deficiency is widespread in the Malawi population. The selenium concentration in maize, the staple food crop of Malawi, can be increased by applying selenium-enriched fertilizers. It is unknown whether this strategy, called agronomic biofortification, is effective at alleviating selenium deficiency. Objectives: The aim of the Addressing Hidden Hunger with Agronomy (AHHA) trial was to determine whether consumption of maize flour, agronomically-biofortified with selenium, affected the serum selenium concentrations of women, and children in a rural community setting. Design: An individually-randomized, double-blind placebo-controlled trial was conducted in rural Malawi. Participants were randomly allocated in a 1:1 ratio to receive either intervention maize flour biofortified with selenium through application of selenium fertilizer, or control maize flour not biofortified with selenium. Participant households received enough flour to meet the typical consumption of all household members (330 g capita -1 day-1) for a period of 8 weeks. Baseline and endline serum selenium concentration (the primary outcome) was measured by inductively coupled plasma mass spectrometry (ICP-MS). Results: One woman of reproductive age (WRA) and one school-aged child (SAC) from each of 180 households were recruited and households were randomized to each group. The baseline demographic and socioeconomic status of participants were well-balanced between arms. No serious adverse events were reported. In the intervention arm, mean (standard deviation) serum selenium concentration increased over the intervention period from 57.6 (17.0) μg L-1 (n = 88) to 107.9 (16.4) μg L-1 (n = 88) among WRA and from 46.4 (14.8) μg L-1 (n = 86) to 97.1 (16.0) μg L-1 (n = 88) among SAC. There was no evidence of change in serum selenium concentration in the control groups. Conclusion: Consumption of maize flour biofortified through application of selenium-enriched fertilizer increased selenium status in this community providing strong proof of principle that agronomic biofortification could be an effective approach to address selenium deficiency in Malawi and similar settings. Clinical Trial Registration: http://www.isrctn.com/ISRCTN85899451, identifier: ISRCTN85899451.