Oxidative stress and antioxidant defenses in mild cognitive impairment: A systematic review and meta-analysis

Effects of Astaxanthin Supplementation on Fatigue, Motor Function and Cognition: A Meta-Analysis of Randomized Controlled Trials

Dietary astaxanthin supplementation has been demonstrated to have many beneficial and health-promoting effects. The purpose of this systematic review and meta-analysis was to assess the effect of astaxanthin supplementation on fatigue, cognition, and exercise efficiency. A total of 11 randomized controlled trials (RCTs) with 346 healthy participants were included. The random effects model and pooled standardized mean difference (SMDs) were used according to Hedge's g for the meta-analysis, and a meta-regression was also conducted. The results of the two existing studies showed a positive trend for astaxanthin in subjective fatigue relief. The effects of astaxanthin supplementation for 8-12 weeks on cognitive accuracy were marginally significant (SMD: .12; 95% CI: -.02-.26) and on reaction time was not significant (SMD: -.08; 95% CI: -.26 to .10). Remarkably, astaxanthin supplementation combined with regular training could enhance the fat oxidation (SMD: 2.56; 95% CI: 1.24-3.89), and significantly improve the physical performance (SMD: .62; 95% CI: .17-1.06). The subgroup analysis further showed significantly greater benefits when performing the aerobic exercises performance (SMD: .45; 95% CI: .13-.76), when the dose was ≥ 20 mg (SMD: .37; 95% CI: .11-.63), and when the supplementation duration was > 12 weeks (SMD: .66; 95% CI: .13-.63). We conclude that astaxanthin supplementation could significantly enhance aerobic exercise efficiency, especially at higher doses and for longer durations. Further studies based on large sample sizes are imperatively warranted.

Ligustilide-loaded liposome ameliorates mitochondrial impairments and improves cognitive function via the PKA/AKAP1 signaling pathway in a mouse model of Alzheimer's disease

BACKGROUND

Oxidative stress is an early event in the development of Alzheimer's disease (AD) and maybe a pivotal point of interaction governing AD pathogenesis; oxidative stress contributes to metabolism imbalance, protein misfolding, neuroinflammation and apoptosis. Excess reactive oxygen species (ROS) are a major contributor to oxidative stress. As vital sources of ROS, mitochondria are also the primary targets of ROS attack. Seeking effective avenues to reduce oxidative stress has attracted increasing attention for AD intervention.

METHODS

We developed liposome-packaged Ligustilide (LIG) and investigated its effects on mitochondrial function and AD-like pathology in the APPswe/PS1dE9 (APP/PS1) mouse model of AD, and analyzed possible mechanisms.

RESULTS

We observed that LIG-loaded liposome (LIG-LPs) treatment reduced oxidative stress and β-amyloid (Aβ) deposition and mitigated cognitive impairment in APP/PS1 mice. LIG management alleviated the destruction of the inner structure in the hippocampal mitochondria and ameliorated the imbalance between mitochondrial fission and fusion in the APP/PS1 mouse brain. We showed that the decline in cAMP-dependent protein kinase A (PKA) and A-kinase anchor protein 1 for PKA (AKAP1) was associated with oxidative stress and AD-like pathology. We confirmed that LIG-mediated antioxidant properties and neuroprotection were involved in upregulating the PKA/AKAP1 signaling in APPswe cells in vitro.

CONCLUSION

Liposome packaging for LIG is relatively biosafe and can overcome the instability of LIG. LIG alleviates mitochondrial dysfunctions and cognitive impairment via the PKA/AKAP1 signaling pathway. Our results provide experimental evidence that LIG-LPs may be a promising agent for AD therapy.

Distress Symptoms of Old Age and Mild Cognitive Impairment are Two Distinct Dimensions in Older Adults Without Major Depression

Background

Studies in old adults showed bidirectional interconnections between amnestic mild cognitive impairment (aMCI) and affective symptoms and that adverse childhood experiences (ACE) may affect both factors. Nevertheless, these associations may be confined to older adults with clinical depression.

Aim

To delineate the relationship between clinical symptoms of aMCI and affective symptoms in older adults without major depression (MDD) or dysfunctions in activities of daily living (ADL).

Methods

This case-control study recruited 61 participants with aMCI (diagnosed using Petersen's criteria) and 59 older adults without aMCI and excluded subjects with MDD and ADL dysfunctions.

Results

We uncovered 2 distinct dimensions, namely distress symptoms of old age (DSOA), comprising affective symptoms, perceived stress and neuroticism, and mild cognitive dysfunctions, comprising episodic memory test scores, the total Mini-Mental State Examination (MMSE) and Montreal Cognitive Assessment (MoCA) scores. A large part of the variance (37.9%) in DSOA scores was explained by ACE, negative life events (health and financial problems), a subjective feeling of cognitive decline, and education (all positively). ACE and NLE have a highly significant impact on the DSOA score and are not associated with aMCI or its severity. Cluster analysis showed that the diagnosis of aMCI is overinclusive because some subjects with DSOA symptoms may be incorrectly classified as aMCI.

Conclusion

The clinical impact is that clinicians should carefully screen older adults for DSOA after excluding MDD. DSOA might be misinterpreted as aMCI.

Phytochemical Extract from Carica papaya Leaves and Punica granatum Seeds as Therapy Against Cognitive Impairment in a Murine Model

Mild cognitive impairment (MCI) is defined as inter-stage between normal cognitive aging and major neurocognitive disorder (MND). This state of decay is a crucial factor in treatment to prevent the progression to MND. In this study, our group developed a virtual screening process to evaluate 2568 phytochemical compounds against 5 key proteins associated with MCI and MND. As a result, two potential candidates were identified: carpaine, found in Carica papaya leaves, and punicalagin, present in Punica granatum. A model of cognitive impairment (CI) was developed in 10-month-old male Sprague Dawley rats by administering aluminum chloride (AlCl3) at a dose of 100 mg/kg/day for 30 days. After AlCl3 administration period, one of the groups received carpaine and punicalagin in a phytochemical extract (PE) by oral gavage for 30 days. Novel object recognition test (NOR) was assessed at three different time points (T1 - before CI, T2 - after CI, and T3 - after PE treatment). Glial fibrillary acidic protein (GFAP) and neurofilament light chain (NfL) were identified in the hippocampus of rats at the end of the study period. After administration of AlCl3, a reduction in discrimination index vs control rats (CI = 0.012 ± 0.08 vs Control = 0.076 ± 0.03), was observed. After phytochemical extract treatment, a significant increase in discrimination index values was observed in the PE group 0.4643 ± 0.13 vs CI group 0.012 ± 0.08. Additionally, the evaluation of immunohistochemistry showed an increase in GFAP positivity in the hippocampus of the CI groups, while a slight decrease was observed in the PE group. This work addressed a comprehensive methodology that utilized in silico tools to identify phytochemical compounds (carpaine and punicalagin) as potential candidates for affecting key proteins in CI. The phytochemical extract containing carpaine and punicalagin resulted in a trend in the decrease of GFAP expression in the hippocampus and improved recognition memory in rats with CI induced by age and AlCl3 administration.

Inflammation and lipid metabolism as potential biomarkers of memory impairment across type 2 diabetes mellitus and severe mental disorders

INTRODUCTION

Neurocognitive impairment is a transdiagnostic feature across several psychiatric and cardiometabolic conditions. The relationship between inflammatory and lipid metabolism biomarkers and memory performance is not fully understood. This study aimed to identify peripheral biomarkers suitable to signal memory decline from a transdiagnostic and longitudinal perspective.

METHODS

Peripheral blood biomarkers of inflammation, oxidative stress and lipid metabolism were assessed twice over a 1-year period in 165 individuals, including 30 with schizophrenia (SZ), 42 with bipolar disorder (BD), 35 with major depressive disorder (MDD), 30 with type 2 diabetes mellitus (T2DM), and 28 healthy controls (HCs). Participants were stratified by memory performance quartiles, taking as a reference their global memory score (GMS) at baseline, into categories of high memory (H; n = 40), medium to high memory (MH; n = 43), medium to low memory (ML; n = 38) and low memory (L; n = 44). Exploratory and confirmatory factorial analysis, mixed one-way analysis of covariance and discriminatory analyses were performed.

RESULTS

L group was significantly associated with higher levels of tumor necrosis factor-alpha (TNF-α) and lower levels of apolipoprotein A1 (Apo-A1) compared to those from the MH and H groups (p < 0.05; η2p = 0.06-0.09), with small to moderate effect sizes. Moreover, the combination of interleukin-6 (IL-6), TNF-α, c-reactive protein (CRP), Apo-A1 and Apo-B compounded the transdiagnostic model that best discriminated between groups with different degrees of memory impairment (χ2 = 11.9-49.3, p < 0.05-0.0001).

CONCLUSIONS

Inflammation and lipid metabolism seem to be associated with memory across T2DM and severe mental illnesses (SMI). A panel of biomarkers may be a useful approach to identify individuals at greater risk of neurocognitive impairment. These findings may have a potential translational utility for early intervention and advance precision medicine in these disorders.

Ameliorative effects of thiamin on learning behavior and memory dysfunction in a rat model of hypothyroidism: implication of oxidative stress and acetylcholinesterase

Hypothyroidism causes learning and memory impairment. Considering the neuroprotective properties of thiamine (Vitamin B1), this study was conducted to investigate the effects of thiamine on acetylcholinesterase (AChE) activity, oxidative damage, and memory deficits in hypothyroid rats.In this study, 50 rats (21 days old) were randomly divided into 5 groups and treated with propylthiouracil (0.05% in drinking water) and thiamine (50, 100, and 200 mg/kg, oral) for 7 weeks. Following that, Morris water maze (MWM) and passive avoidance (PA) tests were performed. Finally, oxidative stress indicators and AChE activity were measured in brain tissue.Treatment of hypothyroid rats with thiamine, especially at 100 and 200 mg/kg, alleviated the ability to remember the location of the platform as reflected by less time spent and distance to reach the platform, during the MWM test (P < 0.05 to P < 0.001). In the PA test, the latency to enter the dark chamber and light stay time were increased in rats who received thiamine compared to the hypothyroid group (P < 0.05 to P < 0.001). In addition, thiamine increased the levels of total thiol groups and superoxide dismutase while decreasing the levels of malondialdehyde and AChE.Our results suggest that thiamine supplementation could effectively improve memory loss in a rat model of hypothyroidism. The positive effects of thiamin on the learning and memory of hypothyroid rats may be due to amelioration of redox hemostasis and cholinergic disturbance.

Neuropsychiatric disturbances in mild cognitive impairment: A scientometric analysis

Behavioral and psychological symptoms of dementia (BPSD) have been extensively studied in dementia than its prodromal stage, known as mild cognitive impairment (MCI). A scientometric study on BPSD in MCI would be valuable in synthesizing the existing body of research and providing insights into the trends, networks, and influencers within this area. We searched for related literature in the Web of Science database and extracted complete text and citation records of each publication. The primary objective was to map the research evolution of BPSD in MCI and highlight dominant research themes. The secondary objective was to identify research network characteristics (authors, journals, countries, and institutions) and abundances. A total of 12,369 studies published between 1980 and 2022 were included in the analysis. We found 51 distinct clusters from the co-cited reference network that were highly credible with significant modularity (Q = 0.856) and silhouette scores (S = 0.932). Five major research domains were identified: symptoms, diagnosis, brain substrates, biochemical pathways, and interventions. In recent years, the research focus in this area has been on gut microbiota, e-health, COVID-19, cognition, and delirium. Collectively, findings from this scientometric analysis can help clarify the scope and direction of future research and clinical practices.

Investigating the Therapeutic Potential of Plants and Plant-Based Medicines: Relevance to Antioxidant and Neuroprotective Effects

Oxidative stress is a common characteristic of psychiatric, neurological, and neurodegenerative disorders. Therefore, compounds that are neuroprotective and reduce oxidative stress may be of interest as novel therapeutics. Phenolic, flavonoid and anthocyanin content, ORAC and DPPH free radical scavenging, and Cu2+ and Fe2+ chelating capacities were examined in variations (fresh/capsule) of Queen Garnet plum (QGP, Prunus salicina), black pepper (Piper nigrum) clove (Syzygium aromaticum), elderberry (Sambucus nigra), lemon balm (Melissa officinalis) and sage (Salvia officinalis), plus two blends (Astralagus membranaceus-lemon balm-rich, WC and R8). The ability of samples to prevent and treat H2O2-induced oxidative stress in SH-SY5Y cells was investigated. Pre-treatment with WC, elderberry, QGP, and clove prevented the oxidative stress-induced reduction in cell viability, demonstrating a neuroprotective effect. Elderberry increased cell viability following oxidative stress induction, demonstrating treatment effects. Clove had the highest phenolic and flavonoid content, DPPH, and Cu2+ chelating capacities, whereas QGP and elderberry were highest in anthocyanins. Black pepper had the highest ORAC and Fe2+ chelating capacity. These findings demonstrate that plant extracts can prevent and treat oxidative stress-induced apoptosis of neuron-like cells in vitro. Further research into phytochemicals as novel therapeutics for oxidative stress in the brain is needed.

Vascular mechanisms leading to progression of mild cognitive impairment to dementia after COVID-19: Protocol and methodology of a prospective longitudinal observational study

INTRODUCTION

Mild cognitive impairment (MCI) is a prodromal stage to dementia, affecting up to 20% of the aging population worldwide. Patients with MCI have an annual conversion rate to dementia of 15-20%. Thus, conditions that increase the conversion from MCI to dementia are of the utmost public health concern. The COVID-19 pandemic poses a significant impact on our aging population with cognitive decline as one of the leading complications following recovery from acute infection. Recent findings suggest that COVID-19 increases the conversion rate from MCI to dementia in older adults. Hence, we aim to uncover a mechanism for COVID-19 induced cognitive impairment and progression to dementia to pave the way for future therapeutic targets that may mitigate COVID-19 induced cognitive decline.

METHODOLOGY

A prospective longitudinal study is conducted at the University of Oklahoma Health Sciences Center. Patients are screened in the Department of Neurology and must have a formal diagnosis of MCI, and MRI imaging prior to study enrollment. Patients who meet the inclusion criteria are enrolled and followed-up at 18-months after their first visit. Visit one and 18-month follow-up will include an integrated and cohesive battery of vascular and cognitive measurements, including peripheral endothelial function (flow-mediated dilation, laser speckle contrast imaging), retinal and cerebrovascular hemodynamics (dynamic vessel retinal analysis, functional near-infrared spectroscopy), and fluid and crystalized intelligence (NIH-Toolbox, n-back). Multiple logistic regression will be used for primary longitudinal data analysis to determine whether COVID-19 related impairment in neurovascular coupling and increases in white matter hyperintensity burden contribute to progression to dementia.

Salivary Oxytocin and Antioxidative Response to Robotic Touch in Adults with Autism Spectrum Disorder

Individuals with ASD are known to have a tendency to have tactile sensory processing issues that could be associated with their impairment as regards social communication. The alterations in tactile processing in autistic subjects are usually accompanied by hypersensitivity and other unpleasant emotions induced by tactile contact. In our study, we investigated the impact of the velocity and the force of a tactile stroke received impersonally by a custom-built robotic device. A total of 21 adults with ASD and 22 adults from a control group participated in our study. The participants' responses were assessed according to subjective scales, EEG changes, and the dynamics of saliva antioxidants and oxytocin. It was found that the oxytocin level was significantly lower in subjects with ASD but increased after tactile stimulation. However, contrary to expectations, the increase in the oxytocin level in the target group negatively correlated with the subjective pleasantness of tactile stimulation and was probably associated with a stress-induced effect. The basic levels of antioxidants did not differ between the TD and ASD groups; however, these had significantly increased in individuals with ASD by the end of the study. The EEG findings, which revealed enhanced antioxidant levels, contributed to the relief of the cognitive control during the study.

Effects of linalyl acetate on oxidative stress, inflammation and endothelial dysfunction: can linalyl acetate prevent mild cognitive impairment?

Mild cognitive impairment (MCI) is a major public health challenge with an increasing prevalence. Although the mechanisms underlying the development of MCI remain unclear, MCI has been reported to be associated with oxidative stress, inflammatory responses, and endothelial dysfunction, suggesting that agents that reduce these factors may be key to preventing MCI. Currently, no agents have been approved for the treatment of MCI, with the efficacy of commonly prescribed cholinesterase inhibitors remaining unclear. Relatively safe natural products that can prevent the development of MCI are of great interest. Linalyl acetate (LA), the major component of clary sage and lavender essential oils, has been shown to have a variety of pharmacological effects, including anti-hypertensive, anti-diabetic, neuroprotective, anti-inflammatory, and antioxidant properties, which may have the potential for the prevention of MCI. The present review briefly summarizes the pathogenesis of MCI related to oxidative stress, inflammatory responses, and endothelial dysfunction as well as the benefits of LA against these MCI-associated factors. The PubMed and Google Scholar databases were used to search the relevant literature. Further clinical research may lead to the development of new strategies for preventing MCI, particularly in high-risk populations with oxidative stress, inflammatory responses, and endothelial dysfunction (e.g., patients with hypertension and/or diabetes mellitus).

Quinolinetrione-tacrine hybrids as multi-target-directed ligands against Alzheimer's disease

Multi-target drug discovery is one of the most active fields in the search for new drugs against Alzheimer's disease (AD). This is because the complexity of AD pathological network might be adequately tackled by multi-target-directed ligands (MTDLs) aimed at modulating simultaneously multiple targets of such a network. In a continuation of our efforts to develop MTDLs for AD, we have been focusing on the molecular hybridization of the acetylcholinesterase inhibitor tacrine with the aim of expanding its anti-AD profile. Herein, we manipulated the structure of a previously developed tacrine-quinone hybrid (1). We designed and synthesized a novel set of MTDLs (2-6) by replacing the naphthoquinone scaffold of 1 with that of 2,5,8-quinolinetrione. The most interesting hybrid 3 inhibited cholinesterase enzymes at nanomolar concentrations. In addition, 3 exerted antioxidant effects in menadione-induced oxidative stress of SH-SY5Y cells. Importantly, 3 also showed low hepatotoxicity and good anti-amyloid aggregation properties. Remarkably, we uncovered the potential of the quinolinetrione scaffold, as a novel anti-amyloid aggregation and antioxidant motif to be used in further anti-AD MTDL drug discovery endeavors.

Dietary low- and high-quality carbohydrate intake and cognitive decline: A prospective cohort study in older adults

BACKGROUND & AIMS

The association of dietary intake of carbohydrate (CHO), especially high- and low-quality CHO, with the decline of cognitive function remains uncertain. We aimed to investigate the prospective association of dietary total, low- and high-quality CHO intake with cognitive decline, and further examine the effect of isocaloric substitution with protein or fat, in the elderly population.

METHODS

A total of 3106 Chinese participants aged ≥55 years from China Health and Nutrition Survey (CHNS) were included in this study. Dietary nutrient intake information was collected by 24-h dietary recalls on 3 consecutive days. The cognitive decline was defined as the 5-year decline rates in global or composite cognitive scores based on a subset of items from the Telephone Interview for Cognitive Status-modified (TICS-m).

RESULTS

The median follow-up duration was 5.9 years. There was a significantly positive association of dietary low-quality CHO (per 10 percentage energy [%E] increment, β, 0.06; 95%CI, 0.01-0.11) and a no significant association of dietary high-quality CHO (per 10%E increment, β, 0.04; 95%CI, -0.07-0.14) with the 5-year decline rate in the composite cognitive scores. Similar results were found for the global cognitive scores. In model simulations, substituting dietary low-quality CHO with isocaloric animal protein or fat, instead of isocaloric plant protein or fat, was significantly and inversely associated with cognitive decline (All P values < 0.05).

CONCLUSIONS

The dietary intake of low-quality CHO, rather than high-quality CHO, was significantly associated with a faster cognitive decline in the elderly. In model simulations, isocaloric substitution of dietary low-quality CHO with animal protein or fat, rather than plant protein or fat, was inversely associated with cognitive decline.

Plasma and cerebrospinal fluid nonenzymatic protein damage is sustained in Alzheimer's disease

BACKGROUND

Oxidative stress is considered to play an important role in the pathogenesis of Alzheimer's disease (AD). It has been observed that oxidative damage to specific protein targets affecting particular functional networks is one of the mechanisms by which oxidative stress contributes to neuronal failure and consequently loss of cognition and AD progression. Studies are lacking in which oxidative damage is measured at both systemic and central fluid levels and in the same cohort of patients. We aimed to determine the levels of both plasma and cerebrospinal fluid (CSF) nonenzymatic protein damage in patients in the continuum of AD and to evaluate the relation of this damage with clinical progression from mild cognitive impairment (MCI) to AD.

METHODS

Different markers of nonenzymatic post-translational protein modification, mostly from oxidative processes, were detected and quantified in plasma and CSF by isotope dilution gas chromatography‒mass spectrometry using selected ion monitoring (SIM-GC/MS) for 289 subjects: 103 AD, 92 MCI, and 94 control subjects. Characteristics of the study population such as age, sex, Mini-mental state examination, CSF AD biomarkers, and APOE ϵ4, were also considered.

RESULTS

Forty-seven (52.8%) MCI patients progressed to AD during follow-up (58 ± 12.5 months). After controlling for age, sex, and APOE ϵ4 allele, plasma and CSF concentrations of protein damage markers were not associated with either diagnosis of AD or MCI. The CSF levels of nonenzymatic protein damage markers were associated with none of the CSF AD biomarkers. In addition, neither in CSF nor in plasma were the levels of protein damage associated with the MCI to AD progression.

CONCLUSION

The lack of association between both CSF and plasma concentrations of nonenzymatic protein damage markers and AD diagnosis and progression suggests that oxidative damage in AD is a pathogenic mechanism specifically expressed at the cell-tissue level, not in extracellular fluids.

A randomized, open-label clinical trial in mild cognitive impairment with EGb 761 examining blood markers of inflammation and oxidative stress

Although beta-amyloid (Aβ) and phosphorylated tau remain the preferred targets for disease-modifying treatments (DMT) against Alzheimer's disease (AD), part of the pathophysiological mechanisms of cognitive impairment are related to neuroinflammation and oxidative stress. In mild cognitive impairment (MCI), a prodromal stage of AD and other neurodegenerative conditions, the joint appearance of inflammation, oxidative stress, and metabolic alterations are the common pathways of neurotoxicity and neurodegeneration. The standardized extract of Ginkgo biloba EGb 761 interferes with the pathogenic mechanisms involved in both the development of cognitive impairment due to AD and that of vascular origin. The primary objective of this study is to compare changes in the levels of blood markers of inflammation and oxidative stress after treatment with EGb 761 in a cohort of 100 patients with MCI. In addition, we aim to assess changes in these blood markers during an additional 12-month extension phase in which patients in the control group will also receive EGb 761 and patients in the active group will extend their treatment duration. Secondary objectives include comparing changes in neuropsychiatric and cognitive test scores between the baseline (v0) and 12-month visits (v2). This study is a Phase IV, single-center, randomized, open-label, parallel-group clinical trial consisting of the 12-month follow-up of a cohort of participants with MCI [Global Deterioration Scale (GDS) = 3] and an extension with an additional 12-month follow-up. During the first 12 months, participants will be randomized into two arms: in one arm, patients will receive 1 daily tablet of EGb 761 240 mg orally (study group, n = 50), while in the other arm, patients will not receive EGb 761 and will undergo the same assessments as the treated group (control group, n = 50). After the first 12 months of the study, patients in the EGb 761-treated group will continue treatment, and patients in the control group will be offered one EGb 761 240 mg tablet per day orally. All participants will be monitored for an additional 12 months. A battery of blood markers of inflammation and oxidative stress will be quantified at v0, v1, v2, v3, and v4. The Olink Proteomics panel of inflammation markers ( https://www.olink.com/products/inflammation/ ) will be used to evaluate 92 proteins associated with inflammatory diseases and related biological processes. The second panel measures 92 proteins involved in neurological processes. At v0, v2, and v4, neuropsychological and neurological evaluations will be conducted in addition to vital signs and anthropometric studies using a body composition monitor with bioimpedance technology (Tanita). Sixty percent of the 100 MCI patients recruited were women. The mean age was 73.1 years, and the mean time between symptom onset and MCI diagnosis was 2.9 years. The mean Mini-Mental State Examination (MMSE) score was 26.7. Depressive and anxiety disorders, as well as vascular risk factors, were the most frequent comorbidities among the cohort. The study is still ongoing, and results for the first year of treatment (v0, v1, v2) are expected by 2023. Individuals with MCI have an elevated risk of developing dementia. EGb 761 is used worldwide for the symptomatic treatment of cognitive disorders due to its neuroprotective effects. In experimental models and clinical observational studies, EGb 761 has shown strong antioxidant and anti-inflammatory activity. As a result, this study has been proposed to evaluate the antioxidant and anti-inflammatory effects on plasma markers and their potential clinical correlation with the progression of cognitive decline in patients with MCI.Trial registration: Registro Español de estudios clínicos (REec) number 2020-003776-41, ClinicalTrials.gov Identifier: NCT05594355.

Selenium Status and Oxidative Stress in SARS-CoV-2 Patients

Background and Objectives: Insufficient intake of essential micronutrient selenium (Se) increases the susceptibility to diseases associated with oxidative stress. The study aim was to assess Se status and oxidative stress in COVID-19 patients depending on severity of the disease. Materials and Methods: Blood plasma of 80 post-COVID-19 disease patients and 40 acutely ill patients were investigated. Concentration of Se was detected by a fluorometric method with di-amino-naphthalene using acidic hydrolysis. Selenoprotein P (Sepp1), malondialdehyde (MDA), and 4-hydroxynonenal (4-HNE) and their metabolite adducts were evaluated by spectrophotometric methods using commercial assay kits. Results: Obtained results demonstrated that Se and Sepp1 concentration in acute patients were significantly (p < 0.05 for Se and p < 0.001 for Sepp1) decreased compared with post-COVID-19 disease patients. However, in post-COVID-19 disease patients, Se values were close to the low limit of the norm for the European population. 4-HNE adducts concentration as a marker of lipid peroxidation was significantly increased in the acute patients group compared to the recovery group (p < 0.001). Conclusions: COVID-19 pathology is characterized by the induction of oxidative stress and suppression of antioxidant defenses during the acute phase. Lower levels of Se and Sepp1 and higher levels of reactive oxygen species reflect this imbalance, highlighting the role of oxidative stress in the disease’s pathogenesis.