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Antioxidants (Basel, Switzerland) Feb 2022Tree nuts, including Brazil nuts, have been hypothesized to impact cardiovascular health through the modulation of oxidative stress and inflammation. Nonetheless, a... (Review)
Review
Effect of Brazil Nuts on Selenium Status, Blood Lipids, and Biomarkers of Oxidative Stress and Inflammation: A Systematic Review and Meta-Analysis of Randomized Clinical Trials.
Tree nuts, including Brazil nuts, have been hypothesized to impact cardiovascular health through the modulation of oxidative stress and inflammation. Nonetheless, a quantitative analysis of these effects has not been performed. Therefore, the aim of this study was to systematically revise and quantify the effect of Brazil nut intervention on selenium status, blood lipids, and biomarkers of oxidative stress and inflammation using a meta-analytical approach. To meet the goals of this study, a systematic search of PubMed, EMBASE, and Web of Science databases of published randomised clinical trials reporting on dietary interventions with Brazil nuts and their effects on selenium status, blood lipids, and markers of oxidative stress and inflammation was performed. Eight articles were included for systematic review and meta-analysis. Based on the conducted analysis, a significant positive effect of Brazil nuts on selenium blood concentration (SMD = 6.93, 95% CI: 3.99; 9.87) was found. Additionally, a positive effect of Brazil nut intervention on glutathione peroxidase activity (SMD = 0.53, 95% CI: 0.07; 0.99) was observed. However, no significant results were found when considering blood lipid levels, including results for total cholesterol (SMD = -0.22, 95% CI: -0.57; 0.14), HDL cholesterol (SMD = -0.04, 95% CI: -0.28; 0.19) and LDL cholesterol (SMD = -0.15; 95% CI: -0.43; 0.13). In conclusion, the findings from this study suggest that Brazil nut consumption improves selenium status and exerts antioxidant effects, which could be considered a potential pathway for the prevention of metabolic disorders related to altered blood lipid profiles. However, further studies are needed to elucidate the effect of Brazil nuts toward blood lipid profile, also preferably controlling for other biomarkers.
PubMed: 35204285
DOI: 10.3390/antiox11020403 -
Cerebrovascular Diseases (Basel,... 2022Stroke is characterized by deleterious oxidative stress. Selenoprotein enzymes are essential endogenous antioxidants, and detailed insight into their role after stroke... (Meta-Analysis)
Meta-Analysis
INTRODUCTION
Stroke is characterized by deleterious oxidative stress. Selenoprotein enzymes are essential endogenous antioxidants, and detailed insight into their role after stroke could define new therapeutic treatments. This systematic review aimed to elucidate how blood selenoprotein concentration and activity change in the acute phase of stroke.
METHODS
We searched PubMed, EMBASE, and Medline databases for studies measuring serial blood selenoprotein concentration or activity in acute stroke patients or in stroke patients compared to non-stroke controls. Meta-analyses of studies stratified by the type of stroke, blood compartment, and type of selenoprotein measurement were conducted.
RESULTS
Eighteen studies and data from 941 stroke patients and 708 non-stroke controls were included in this review. Glutathione peroxidase (GPx) was the only identified selenoprotein, and its activity was most frequently measured. Results from 12 studies and 693 patients showed that compared to non-stroke controls in acute ischaemic stroke patients, the GPx activity increased in haemolysate (standardized mean difference [SMD]: 0.27, 95% CI: 0.07-0.47) but decreased in plasma (mean difference [MD]: -1.08 U/L, 95% CI: -1.94 to -0.22) and serum (SMD: -0.54, 95% CI: -0.91 to -0.17). From 4 identified studies in 106 acute haemorrhagic stroke patients, the GPx activity decreased in haemolysate (SMD: -0.40, 95% CI: -0.68 to -0.13) and remained unchanged in plasma (MD: -0.10 U/L, 95% CI: -0.81 to 0.61) and serum (MD: -5.00 U/mL, 95% CI: -36.17 to 26.17) compared to non-stroke controls. Results from studies assessing the GPx activity in the haemolysate compartment were inconsistent and characterized by high heterogeneity.
CONCLUSIONS
Our results suggest a reduction of the blood GPx activity in acute ischaemic stroke patients, a lack of evidence regarding a role for GPx in haemorrhagic stroke patients, and insufficient evidence for other selenoproteins.
Topics: Antioxidants; Brain Ischemia; Glutathione Peroxidase; Hemorrhagic Stroke; Humans; Ischemic Stroke; Selenium; Selenoproteins
PubMed: 34983048
DOI: 10.1159/000520856 -
The Journal of International Medical... Dec 2021To perform a meta-analysis of randomized controlled trials to evaluate the efficacy of vitamin D supplementation on thyroid autoimmunity markers in Hashimoto's... (Meta-Analysis)
Meta-Analysis
OBJECTIVE
To perform a meta-analysis of randomized controlled trials to evaluate the efficacy of vitamin D supplementation on thyroid autoimmunity markers in Hashimoto's thyroiditis (HT).
METHODS
This meta-analysis included randomized controlled clinical trials identified by a systematic search of electronic databases (PubMed®, MEDLINE®, EMBASE, The Cochrane Library, China National Knowledge Infrastructure) from inception to August 2020. All studies included patients with HT that received vitamin D supplementation irrespective of the doses administered or the duration of treatment. The primary and secondary outcome measures were thyroid peroxidase antibody (TPOAb) and/or thyroglobulin antibody (TGAb) titres.
RESULTS
Eight studies ( = 652) were included. There was significant heterogeneity between the studies. Using a random-effect model, vitamin D supplementation reduced TPOAb titre (standardized mean difference [SMD]: -1.11; 95% confidence interval [CI]: 1-1.92, -0.29) and TGAb titre (SMD: -1.12; 95% CI: -1.96, -0.28). A subgroup analysis demonstrated that vitamin D supplementation for >3 months resulted in a decrease in TPOAb titre (SMD: -1.66, 95% CI: -2.91, -0.41) but treatment ≤3 months was ineffective. Treatment with vitamin D decreased TPOAb titre (SMD: -1.48; 95% CI: -2.53, -0.42) whereas vitamin D did not.
CONCLUSION
These data suggest that vitamin D reduces autoantibody titre in patients with HT.
Topics: Autoimmunity; Dietary Supplements; Hashimoto Disease; Humans; Vitamin D
PubMed: 34871506
DOI: 10.1177/03000605211060675 -
Antioxidants (Basel, Switzerland) Nov 2021Statins may exert protective effects against oxidative stress by upregulating specific antioxidant mechanisms. We conducted a systematic review and meta-analysis of the... (Review)
Review
Statins may exert protective effects against oxidative stress by upregulating specific antioxidant mechanisms. We conducted a systematic review and meta-analysis of the effect of statins on three key antioxidant enzymes: glutathione peroxidase (GPx), superoxide dismutase (SOD), and catalase. The electronic databases PubMed, Web of Science, and Scopus were searched from inception to July 2021. The risk of bias was assessed with the Joanna Briggs Institute Critical Appraisal Checklist and certainty of evidence was assessed using the GRADE framework. In 15 studies, reporting 17 treatment arms in 773 patients (mean age 53 years, 54% males), statins significantly increased the concentrations of both GPx (standardized mean difference, SMD = 0.80, 95% confidence interval, CI 0.13 to 1.46, = 0.018; high certainty of evidence) and SOD (SMD = 1.54, 95% CI 0.71 to 2.36, < 0.001; high certainty of evidence), but not catalase (SMD = -0.16, 95% CI -0.51 to 0.20, = 0.394; very low certainty of evidence). The pooled SMD values were not altered in sensitivity analysis. There was no publication bias. In conclusion, statin treatment significantly increases the circulating concentrations of GPx and SOD, suggesting an antioxidant effect of these agents (PROSPERO registration number: CRD42021271589).
PubMed: 34829712
DOI: 10.3390/antiox10111841 -
Antioxidants (Basel, Switzerland) Oct 2021Chronic obstructive pulmonary disease (COPD) is a progressive disease that is characterized by a state of persistent inflammation and oxidative stress. The presence of... (Review)
Review
Chronic obstructive pulmonary disease (COPD) is a progressive disease that is characterized by a state of persistent inflammation and oxidative stress. The presence of oxidative stress in COPD is the result of an imbalance between pro-oxidant and antioxidant mechanisms. The aim of this review was to investigate a possible association between glutathione peroxidase (GPx), a key component of antioxidant defense mechanisms, and COPD. A systematic search for relevant studies was conducted in the electronic databases PubMed, Web of Science, Scopus, and Google Scholar, from inception to June 2021. Standardized mean differences (SMDs) were used to express the differences in GPx concentrations between COPD patients and non-COPD subjects. Twenty-four studies were identified. In 15 studies assessing whole blood/erythrocytes (GPx isoform 1), the pooled results showed that GPx concentrations were significantly lower in patients with COPD (SMD = -1.91, 95% CI -2.55 to -1.28, < 0.001; moderate certainty of evidence). By contrast, in 10 studies assessing serum/plasma (GPx isoform 3), the pooled results showed that GPx concentrations were not significantly different between the two groups (very low certainty of evidence). The concentration of GPx-1, but not GPx-3, is significantly lower in COPD patients, suggesting an impairment of antioxidant defense mechanisms in this group.
PubMed: 34829616
DOI: 10.3390/antiox10111745 -
Biological Trace Element Research Sep 2022Several studies have indicated that selenium deficiency may be detrimental in the context of various viral disorders, and in the case of COVID-19, several studies have...
Several studies have indicated that selenium deficiency may be detrimental in the context of various viral disorders, and in the case of COVID-19, several studies have reported heterogeneous results concerning the association of selenium deficiency with the severity of disease. To summarize the available data surrounding the association of body selenium levels with the outcomes of COVID-19, a systematic search was performed in the Medline database (PubMed), Scopus, Cochrane Library, Embase, and Web of Science using keywords including "SARS-CoV-2," "COVID-19," and "selenium," Studies evaluating the association of COVID-19 with body selenium levels were included. Among 1,862 articles viewed in the database search, 10 articles were included after title, abstract, and full-text review. One study was further included after searching the literature again for any newly published articles. Out of 11 included studies, 10 studies measured serum selenium level, and one study investigated urinary selenium level. Three of 10 studies measured serum SELENOP level as well as selenium level. Glutathione peroxidase-3 level in serum was also assessed in one study. The reported outcomes were severity, mortality, and risk of COVID-19. Nine studies indicated that a lower serum selenium level is associated with worse outcomes. Two studies reported no significant association between serum selenium level and COVID-19. In one study, urinary selenium level was reported to be higher in severe and fatal cases compared to non-severe and recovered patients, respectively. In most cases, selenium deficiency was associated with worse outcomes, and selenium levels in COVID-19 patients were lower than in healthy individuals. Thus, it could be concluded that cautious selenium supplementation in COVID-19 patients may be helpful to prevent disease progression. However, randomized clinical trials are needed to confirm this.
Topics: COVID-19; Humans; Malnutrition; SARS-CoV-2; Selenium; Selenoprotein P
PubMed: 34739678
DOI: 10.1007/s12011-021-02997-4 -
BioMed Research International 2021Type 2 deiodinase (Dio2) is a selenoenzyme that is mainly expressed in the endoplasmic reticulum of the central nervous system, brown adipose tissue, and placenta and is... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Type 2 deiodinase (Dio2) is a selenoenzyme that is mainly expressed in the endoplasmic reticulum of the central nervous system, brown adipose tissue, and placenta and is responsible for outer ring deiodination of thyroxine (T4) to form biologically active triiodothyronine (T3). The Thr92Ala polymorphism of Dio2 has been found to be a potential risk factor for various diseases beyond the hypothalamus-pituitary-thyroid (HPT) axis.
METHODS
We searched the relevant studies in the PubMed, Embase, and Cochrane Library databases and Google Scholar. A systematic review and meta-analysis of studies on the Thr92Ala polymorphism and metabolic parameters beyond the HPT axis (e.g., BMI, fasting glycemic traits, plasma lipid levels, and hypertension risk) were performed.
RESULTS
Six eligible studies that analyzed the relationship between the Thr92Ala polymorphism and metabolic parameters beyond the thyroid were identified. All selected studies excluded patients with thyroid dysfunction, and diabetic patients were also excluded when fasting glucose and fasting insulin levels were meta-analyzed. The Thr92Ala polymorphism was found to be a significant risk factor for higher BMI (Std. mean difference 0.31 (0.01, 0.60), = 0.04) and higher fasting glucose levels (Std. mean difference 1.18 (0.05, 2.31), = 0.04). However, fasting insulin levels, plasma lipid levels, and hypertension risk showed a nonsignificant association with the Thr92Ala polymorphism.
CONCLUSION
Compared with euthyroid noncarriers (Thr/Thr), euthyroid Ala92-Dio2 carriers showed increased BMI levels, and Ala92-Dio2 carriers also had higher fasting plasma glucose levels than matched euthyroid nondiabetic noncarriers.
Topics: Adolescent; Adult; Aged; Aged, 80 and over; Blood Glucose; Body Mass Index; Fasting; Female; Genetic Association Studies; Humans; Hypertension; Iodide Peroxidase; Lipids; Male; Middle Aged; Polymorphism, Single Nucleotide; Risk Factors; Young Adult
PubMed: 34660805
DOI: 10.1155/2021/9914009 -
Health Science Reports Dec 2021Oxidative stress plays a major role in the development of type 2 diabetes mellitus (T2DM). However, there were controversial outcomes in the literature between the...
BACKGROUND AND AIMS
Oxidative stress plays a major role in the development of type 2 diabetes mellitus (T2DM). However, there were controversial outcomes in the literature between the association of oxidative stress biomarkers and T2DM. The purpose of this systematic review and meta-analysis was to critically examine the association of oxidative stress biomarkers with T2DM.
METHODS
We systematically searched different electronic databases including PubMed/Medline, EMBASE, ScienceDirect, Web of Science, and Cochrane Library to find the relevant studies up to May 2021. The pooled standard mean difference (SMD) with a 95% confidence interval (CI) was used to define the variation between the study groups.
RESULTS
A total of 22 case-control studies with 2853 subjects (1667 diabetic patients and 1186 healthy controls) were found to be eligible for this meta-analysis. The pooled results of meta-analysis showed a significant difference in the levels malondialdehyde (SMD [95% CI]: 2.27 [1.62, 2.91]), nitric oxide (SMD [95% CI]: 1.40 [0.00, 2.81]), glutathione (SMD [95% CI]: -1.76 [-2.94, -0.59]), and total antioxidant status (SMD [95% CI]: -1.40 [-2.28, -0.51]) between the patient group and healthy subjects, whereas no significant difference was observed in the superoxide dismutase levels (SMD [95% CI]: -1.20 [-2.55, 0.15]) and glutathione peroxidase levels (SMD [95% CI]: 0.07 [-2.80, 2.94]).
CONCLUSION
The present analysis suggests that oxidative stress might have a potential role in the pathogenesis of T2DM in humans. However, further studies should be needed to elucidate the possible mechanism and strengthen this evidence.
PubMed: 34622023
DOI: 10.1002/hsr2.389 -
Oxidative Medicine and Cellular... 2021Oral lichen planus (OLP) is a relatively common chronic inflammatory disease of unknown etiology, which might be caused by oxidative stress and impaired antioxidant... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Oral lichen planus (OLP) is a relatively common chronic inflammatory disease of unknown etiology, which might be caused by oxidative stress and impaired antioxidant defense.
OBJECTIVE
To systematically investigate the markers of oxidative stress and antioxidant systems in the saliva and blood from OLP patients and healthy controls.
METHODS
The PubMed, Cochrane Library, and Embase were systematically queried to collect data from studies in which oxidative stress/antioxidant markers from OLP and healthy subjects had been evaluated until March 10, 2021.
RESULTS
A total of 28 studies fulfilled inclusion criteria, and 25 of them, having 849 OLP patients and 1,052 control subjects and analyzing 12 oxidative stress and antioxidant state marker levels, were subjected to meta-analysis. We found a significant decrease in total antioxidant capacity (TAC) and uric acid (UA) and a significant increase in malondialdehyde (MDA) and nitric oxide (NO) levels in the saliva and serum/plasma of OLP patients. Moreover, a significant elevation of 8-hydroxy-deoxyguanosine (8-OHdG) and advanced oxidation protein product (AOOP) level and a decrease in vitamin C were also observed in the saliva of the OLP group. In contrast, salivary vitamin A, zinc, glutathione peroxidase (GPx), vitamin E, and nitrite were not significantly different between the two groups. In single studies, markers of oxidative stresses such as superoxide dismutase (SOD) and 8-isoprostanelevels were elevated in OLP, and antioxidant parameters such as glutathione (GSH) and total protein (TP) levels were dysregulated.
CONCLUSION
This meta-analysis helps to clarify the profile of oxidative stress and antioxidant state markers in OLP patients although existing evidence is rather heterogeneous and many studies are affected by several limitations. Larger and more standardized studies are warranted to ascertain whether these markers are potential causes or effects of OLP and whether antioxidant therapy improving oxidative stress will be useful.
Topics: Adult; Aged; Antioxidants; Biomarkers; Case-Control Studies; Female; Glutathione; Glutathione Peroxidase; Humans; Lichen Planus, Oral; Male; Malondialdehyde; Middle Aged; Nitric Oxide; Oxidative Stress; Saliva; Superoxide Dismutase; Uric Acid
PubMed: 34616506
DOI: 10.1155/2021/9914652 -
Neuropsychiatric Disease and Treatment 2021The term myxedema psychosis (MP) was introduced to describe the occurrence of psychotic symptoms in patients with untreated hypothyroidism, but the optimal assessment... (Review)
Review
BACKGROUND AND OBJECTIVE
The term myxedema psychosis (MP) was introduced to describe the occurrence of psychotic symptoms in patients with untreated hypothyroidism, but the optimal assessment and treatment of this condition are unclear. We aimed to synthesize data from the literature to characterize the clinical presentation and management of MP.
METHODS
We performed a systematic review according to the PRISMA (preferred reporting items for systematic reviews and meta-analyses) guidelines in PubMed (Medline), Embase, Google Scholar, and Cochrane databases, including observational studies, case series, and case reports published from 1/1/1980 to 31/12/2019 in the English language. Descriptive statistics along with univariate and multivariate analysis were used for data synthesis.
RESULTS
Out of 1583 articles screened, 71 case reports met our inclusion criteria providing data on 75 MP cases. The median age at diagnosis was 42 years [32-56]. About 53% had no prior hypothyroidism diagnosis. Delusions occurred in 91%, with a predominance of persecutory ideas (84%), while hallucinations occurred in 78%. Physical symptoms and signs of hypothyroidism were absent in 37% and 26%, respectively. If symptoms occurred, nonspecific fatigue was seen most frequently (63%). The median thyroid-stimulating hormone value was 93 mIU/L [60-139]. Thyroid peroxidase antibodies were found positive in 75% (23/33) of reported cases. Creatinine kinase was reported abnormal in seven cases. Cranial imaging (CT or MRI) and electroencephalogram were normal in 89%, 75%, and 73% of the cases reported. The majority of patients were treated orally with thyroxine in combination with short-term antipsychotics. More than 90% of them showed complete recovery. Univariate analysis revealed a trend towards a shorter duration of psychosis with IV thyroid hormone therapy (= 0.0502), but the effect was not consistent in a multivariate analysis.
CONCLUSION
While we identified a substantial lack of published research on MP, our pooled analysis of case observations suggests that the condition presents a broad spectrum of psychiatric and physical symptoms lending support to the value of screening for thyroid dysfunction in patients with first-ever psychosis.
PROSPERO REGISTRATION NUMBER
CRD42020160310.
PubMed: 34447249
DOI: 10.2147/NDT.S318651