Association of selenium profile with neutralizing antibody response to inactivated SARS-CoV-2 vaccination

BACKGROUND

Selenium profile has been related with humoral immune response after vaccination, but evidence with regard to inactivated SARS-CoV-2 vaccine is lacking.

OBJECTIVE

The current study aimed to examine the relationship between selenium profile and neutralizing antibody response to inactivated SARS-CoV-2 vaccine.

METHODS

Plasma selenium and selenoprotein P concentrations, neutralizing antibody against the wild-type and Omicron variant were measured at baseline and at 14 days, 98 days after the third dose of inactivated SARS-CoV-2 vaccine.

RESULTS

Neutralizing antibody against the wild-type and Omicron variant increased significantly after the third vaccination dose. Both higher plasma selenium and selenoprotein P were associated with increased neutralizing antibody against the wild-type strain at baseline. Moreover, higher plasma selenoprotein P was associated with increased neutralizing antibody against Omicron variant at baseline. However, nonsignificant association were observed after the third vaccine dose.

CONCLUSION

Higher selenium profile was associated with neutralizing antibody response before the third dose of inactivated SARS-CoV-2 vaccine, but not after the third dose. Further prospective cohort studies are warranted to confirm our findings.

Relationship between selenium status, selenoproteins and COVID-19 and other inflammatory diseases: A critical review

The antioxidant effects of selenium as a component of selenoproteins has been thought to modulate host immunity and viral pathogenesis. Accordingly, the association of low dietary selenium status with inflammatory and immunodeficiency has been reported in the literature; however, the causal role of selenium deficiency in chronic inflammatory diseases and viral infection is still undefined. The COVID-19, characterized by acute respiratory syndrome and caused by the novel coronavirus 2, SARS-CoV-2, has infected millions of individuals worldwide since late 2019. The severity and mortality from COVID-19 have been associated with several factor, including age, sex and selenium deficiency. However, available data on selenium status and COVID-19 are limited, and a possible causative role for selenium deficiency in COVID-19 severity has yet to be fully addressed. In this context, we review the relationship between selenium, selenoproteins, COVID-19, immune and inflammatory responses, viral infection, and aging. Regardless of the role of selenium in immune and inflammatory responses, we emphasize that selenium supplementation should be indicated after a selenium deficiency be detected, particularly, in view of the critical role played by selenoproteins in human health. In addition, the levels of selenium should be monitored after the start of supplementation and discontinued as soon as normal levels are reached. Periodic assessment of selenium levels after supplementation is a critical issue to avoid over production of toxic metabolites of selenide because under normal conditions, selenoproteins attain saturated expression levels that limits their potential deleterious metabolic effects.

Potential benefits of selenium supplementation in patients with kidney disease

Trace element deficiency is common among patients with end-stage renal disease (ESRD); the reason is that since these patients undergo dialysis, they lose these elements more than healthy people, and also the use of trace elements is restricted due to loss of appetite. Selenium (Se) is a trace element that is essential for the oxidative stress defense system. Se deficiency leads to some complications similar to those often seen in ESRD patients, such as all-cause mortality due to cardiovascular diseases, bone loss, uric acid elevation, and anemia. This article aims to review the evidence on consequences of Se deficiency in ESRD patients, as well as effects of Se supplementation in hemodialysis patients. Multiple databases were searched to summarize the available evidence on selenium's role in kidney diseases. Since the complications of ESRD and those of Se deficiency are mostly similar, this triggers the idea that Se deficiency may be considered as a cause of these problems, but it needs to be more assessed that Se deficiency is a single factor or there are other factors participated in. Also the role of Se supplementation on resolving the mentioned complications, needs to be more studied through welldesigned clinical studies.

Influence of specific management practices on blood selenium, vitamin E, and beta-carotene concentrations in horses and risk of nutritional deficiency

Background

Selenium or alpha‐tocopherol deficiency can cause neuromuscular disease. Beta‐carotene has limited documentation in horses.

Objective

To evaluate the effect of owner practices on plasma beta‐carotene concentration and risk of selenium and alpha‐tocopherol deficiencies.

Animals

Three‐hundred and forty‐nine adult (≥1 year), university and privately owned horses and mules.

Methods

Cross‐sectional study. Whole blood selenium, plasma alpha‐tocopherol, and plasma beta‐carotene concentrations were measured once. Estimates of daily selenium and vitamin E intake, pasture access, and exercise load were determined by owner questionnaire. Data were analyzed using t tests, Mann‐Whitney tests, parametric or nonparametric analysis of variance (ANOVA), Kruskal‐Wallis test, Spearman's correlation and contingency tables (P < .05).

Results

Nearly 88% of the horses received supplemental selenium; 71.3% received ≥1 mg/d. Low blood selenium concentration (<80 ng/mL) was identified in 3.3% of horses, and 13.6% had marginal concentrations (80‐159 ng/mL). Non‐supplemented horses were much more likely to have low blood selenium (odds ratio [OR], 20.2; 95% confidence interval [CI], 9.26‐42.7; P < .001). Supplemental vitamin E was provided to 87.3% of horses; 57.7% received ≥500 IU/d. Deficient (<1.5 μg/mL) and marginal (1.5‐2.0 μg/mL) plasma (alpha‐tocopherol) occurred in 15.4% and 19.9% of horses, respectively. Pasture access (>6 h/d) and daily provision of ≥500 IU of vitamin E was associated (P < .001) with higher plasma alpha‐tocopherol concentrations. Plasma beta‐carotene concentration was higher in horses with pasture access (0.26 ± 0.43 versus 0.12 ± 0.13 μg/mL, P = .003).

Conclusions and Clinical Importance

Suboptimal blood selenium and plasma alpha‐tocopherol concentrations occurred in 16.7% and 35.5% of horses, respectively, despite most owners providing supplementation. Inadequate pasture access was associated with alpha‐tocopherol deficiency, and reliance on selenium‐containing salt blocks was associated with selenium deficiency.

Relationships of inflamm-aging with circulating nutrient levels, body composition, age, and pituitary pars intermedia dysfunction in a senior horse population

Similarly to aged humans, senior horses (≥20 years) exhibit chronic low-grade inflammation systemically, known as inflamm-aging. Inflamm-aging in the senior horse has been characterized by increased circulating inflammatory cytokines as well as increased inflammatory cytokine production by lymphocytes and monocytes in response to a mitogen. Little is currently known regarding underlying causes of inflamm-aging. However, senior horses are also known to present with muscle wasting and often the endocrinopathy pituitary pars intermedia dysfunction (PPID). Despite the concurrence of these phenomena, the relationships inflamm-aging may have with measures of body composition and pituitary function in the horse remain unknown. Furthermore, nutrition has been a focus of research in an attempt to promote health span as well as life span in senior horses, with some nutrients, such as omega-3 fatty acids, having known anti-inflammatory effects. Thus, an exploratory study of a population of n = 42 similarly-managed senior horses was conducted to determine relationships between inflamm-aging and measures of circulating nutrients, body composition, age, and PPID. Serum was collected to determine vitamin, mineral, and fatty acid content. Peripheral blood mononuclear cells were also isolated to determine inflammatory cytokine production of interferon-γ (IFN-γ) and tumor necrosis factor-α (TNF-α) following stimulation with a mitogen, as well as to determine gene expression of interleukin(IL)-1β, IL-6, IL-10, IFN-γ, and TNF-α. Serum IL-6 and C-reactive protein were determined by enzyme-linked immunosorbent assay. Whole blood was collected for hematological and biochemical analysis. Body composition was evaluated via ultrasound and muscle scoring for all 42 horses as well as by deuterium oxide dilution for a subset of n = 10 horses. Pituitary function was evaluated by measuring basal adrenocorticotropin hormone concentrations as well as by thyrotropin releasing hormone stimulation testing (to determine PPID status). Results showed various relationships between inflammatory markers and the other variables measured. Most notably, docosadienoic acid (C22:2n6c), docosapentaenoic acid (C22:5n3c), and folate were positively associated with numerous inflammatory parameters (P ≤ 0.05). Although no relationships were found between inflamm-aging and PPID, being positive for PPID was negatively associated with vitamin B12 (P ≤ 0.01). No relationships between inflammation and body composition were found. Even within this senior horse population, age was associated with multiple parameters, particularly with numerous inflammatory cytokines and fatty acids. In summary, inflamm-aging exhibited relationships with various other parameters examined, particularly with certain fatty acids. This exploratory study provides insights into physiological changes associated with inflamm-aging in the senior horse.

Uterine Inertia due to Severe Selenium Deficiency in a Parturient Mare

A 12-year-old, multiparous, parturient show jumper embryo-recipient mare presented at a veterinary hospital, seven days past her due date and with a dilated cervix, for evaluation of mild colic. Gastrointestinal or metabolic abnormalities and fetal maldispositions were excluded as causes of dystocia, and a diagnosis of uterine inertia was made. There was no uterine response to oxytocin treatment. A live filly was delivered via C-section, and severe selenium deficiency was eventually confirmed in the mare, her offspring, and in the herd of origin. The filly was born with severe white muscle disease and required intensive treatment. This report suggests that selenium deficiency is an underlying cause of equine uterine inertia in the absence of other causes of dystocia.

Impact of Micronutrients on the Immune Response of Animals

Vitamins and minerals (micronutrients) play an important role in regulating and shaping an immune response. Deficiencies generally result in inadequate or dysregulated cellular activity and cytokine expression, thereby affecting the immune response. Decreased levels of natural killer, granulocyte, and phagocytic cell activity and T and B cell proliferation and trafficking are associated with inadequate levels of micronutrients, as well as increased susceptibility to various adverse health conditions, including inflammatory disorders, infection, and altered vaccine efficacy. In addition, most studies of micronutrient modulation of immune responses have been done in rodents and humans, thus limiting application to the health and well-being of livestock and companion animals. This exploratory review elucidates the role of vitamins and minerals on immune function and inflammatory responses in animals (pigs, dogs, cats, horses, goats, sheep, and cattle), with reference to rodents and humans.

Antibody response to Influenza booster vaccination in Franches-Montagnes stallions supplemented with Equi-Strath® : a randomized trial

Bio-Strath® is a plasmolyzed yeast product enriched with herbs, malt, honey and orange juice. In this study, the effect of Equi-Strath® , the adapted product for horses, on the equine immune system was evaluated. A routine influenza booster vaccination was used as a model to study the effects of Equi-Strath® supplementation on the immune response. Twenty healthy Franches-Montagnes stallions with pre-existing antibody levels were randomly divided into a study group (SG, n = 10) receiving 0.06 mL/kg bodyweight of Equi-Strath® , and a control group (CG, n = 10), receiving the same amount of placebo, daily. The supplement and placebo were given from week 1 until week 14 of the trial. After 10 weeks, the horses were vaccinated with a commercial vaccine containing equine influenza strains of the H3N8 subtype. Antibody titres in blood were measured at day 0 before vaccination, and 14 and 32 days after vaccination. In addition, a complete blood count (CBC) was performed on day 0 and day 32. A linear increase of haemagglutination inhibition titres in both groups was observed after vaccination, but with no difference between treatment groups. CBC components remained unaffected by treatment. In conclusion, daily Equi-Strath® supplementation did not affect the adaptive immune response in stallions after a routine commercial H3N8 influenza booster vaccination.

Selenkonzentration im Serum und Glutathionperoxidaseaktivität im Vollblut bei gesunden adulten Pferden

Gegenstand und Ziel: Überprüfung des Selenstatus von Pferden anhand der Konzentration von Selen (Se) im Serum und der Glutathionperoxidaseaktivität im Vollblut (GPx) zur Ableitung von Referenzbereichen. Material und Methoden: Warmblutpferde aus zwei Betrieben wurden bis zu viermal im Abstand von mindestens 3 Monaten beprobt. Für einen Rassenvergleich fand in drei Betrieben einmalig eine Blutprobenentnahme bei Vollblutpferden, Islandpferden bzw. Kaltblütern statt. Daraus resultierten insgesamt 1167 Blutproben von 528 klinisch gesunden Pferden. Die-Se-Konzentration wurde massenspektrometrisch analysiert, die GPx-Aktivität in heparinisiertem Vollblut photometrisch gemessen und auf den Hämatokrit bezogen. Das Referenzintervall umfasst die zentralen 95% der Werte aller gesammelten Proben adulter (Alter > 1 Jahr) Warmblüter. Ergebnisse: Die Se-Konzentration im Serum betrug 96 ± 38 µg/l, die GPx-Aktivität im Vollblut 94 ± 40 U/ml Hkt (Mittelwert ± Standardabweichung; n = 1167). Bei 48% der Pferde ergaben sich Se-Werte unterhalb des aktuellen Referenzbereichs von 100–200 µg/l. Alter, Rasse, Standort, Fütterung und Jahreszeit hatten einen Einfluss auf den Se-Status der Pferde. Die Korrelation zwischen der GPx-Aktivität und der Se-Konzentration ließ sich mit der linearen Regressionsgleichung y = 0,73 x + 23,76 beschreiben (y = GPx-Aktivität, x = Se) und es bestand eine signifikante positive Korrelation von r = 0,7. Der aus allen Proben (n = 909) adulter Warmblutpferde berechnete Bereich zwischen 2,5%- und 97,5%-Perzentil betrug für die Se-Konzentrationen 34–167 µg/l und für die GPx-Aktivität 34–175 U/ml Hkt. Schlussfolgerung und klinische Relevanz: Aufgrund der hohen prozentualen Anteils gesunder Pferde, deren Se-Werte nicht im Referenzbereich lagen, scheint der bisher geltende Referenzbereich von 100–200 µg/l zu hoch angesetzt zu sein. Anhand der erhobenen Werte wird für die Se-Konzentration im Serum ein Referenzbereich von 70–170 µg/l vorgeschlagen. Als ergänzender Parameter lässt sich die GPx-Aktivität im Vollblut nutzen, für die ein Referenzbereich von 50–175 U/ml Hkt empfohlen wird.