Oxidative Stress Markers in Vitamin B12 Deficiency

Vitamin B12: prevention of human beings from lethal diseases and its food application

Vitamin B12, a water-soluble essential micronutrient, plays a pivotal role in numerous physiological processes in the human body. This review meticulously examines the structural complexity and the diverse mechanisms through which vitamin B12 exerts its preventive effects against a spectrum of health conditions, including pernicious anaemia, neurological disorders, obesity, diabetes, dyslipidaemia and complications in foetal development. The selection of articles for this review was conducted through a systematic search across multiple scientific databases, including PubMed, Scopus and Web of Science. Criteria for inclusion encompassed relevance to the biochemical impact of vitamin B12 on health, peer-reviewed status and publication within the last decade. Exclusion criteria were non-English articles and studies lacking empirical evidence. This stringent selection process ensured a comprehensive analysis of vitamin B12's multifaceted impact on health, covering its structure, bioavailable forms and mechanisms of action. Clinical studies highlighting its therapeutic potential, applications in food fortification and other utilizations are also discussed, underscoring the nutrient's versatility. This synthesis aims to provide a clear understanding of the integral role of vitamin B12 in maintaining human health and its potential in clinical and nutritional applications. © 2024 The Author(s). Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Metalomics Revealed that Changes of Serum Elements were Associated with Oxidative Stress-Induced Inflammation of Cortex in a Mouse Model of Autism

Autism spectrum disorder (ASD) is a neurodevelopmental disorder emerging during early childhood. However, the mechanism underlying the pathogenesis of ASD remains unclear. This study investigated the alterations of elements in serum and prefrontal cortex of BTBR T + tf/J (BTBR) mice and potential mechanisms. The male BTBR mice were used for experimental group and C57BL/6 J (C57) mice were used for control group (n = 15). After behavioral tests were monitored, serum and prefrontal cortex of mice were analyzed by ICP-MS. The results demonstrated that the level of copper (Cu) was increased, and the levels of calcium (Ca), magnesium (Mg), selenium (Se), cobalt (Co), iron (Fe) and zinc (Zn) were decreased in BTBR mice compared to C57 mice (p < 0.01). The levels of above differential elements in serum demonstrated positive correlations with those in prefrontal cortex. Meanwhile, differential elements in prefrontal cortex had correlations with the total distance traveled (open field test) and the number of marbles buried (marble burying test) in BTBR mice (p < 0.05 or p < 0.01). The abnormally changed elements in serum might cross blood-brain-barrier into the brain and lead to oxidative stress, causing inflammation. Furtherly, the levels of inflammation-related indicators including tumor necrosis factor-alpha (TNF-α), nuclear factor kappa-B (NF-κB), interleukin-6 (IL-6) and interleukin-1β (IL-1β) were increased in prefrontal cortex of BTBR mice (p < 0.01), which were consistent with the aforementioned results. Our study suggested that the abnormal elements in the serum of BTBR mice may cause oxidative stress and inflammation in prefrontal cortex, which might contribute to increase the understanding of ASD pathogenesis.

Quercetin Alleviates Perimenopausal Depression Induced by Ovariectomy Combined with Chronic Unpredictable Mild Stress Through Regulating Serum Elements and Inhibiting Ferroptosis in Prefrontal Cortex of Rats

This study investigated the effects of quercetin on the alterations of serum elements in perimenopausal depression rat model induced by ovariectomy combined with chronic unpredictable mild stress (OVX-CUMS) and possible mechanisms. According to the results of the sucrose preference test, the rats were randomly assigned to four groups: sham, OVX-CUMS, OVX-CUMS + 17β-estradiol (17β-estradiol: 0.27 mg/kg.bw), and OVX-CUMS + Quercetin (Quercetin: 50 mg/kg.bw). At the end of experiment, serum and prefrontal cortex of rats were collected. The inductively coupled plasma mass spectrometry (ICP-MS) analysis showed that levels of calcium (Ca), magnesium (Mg), selenium (Se), cobalt (Co) and zinc (Zn) decreased, and levels of iron (Fe) and copper (Cu) increased in serum and prefrontal cortex of OVX-CUMS rats compared with sham group (p < 0.01). Meanwhile, the levels of the above elements in prefrontal cortex had correlation with behavioral characteristics in OVX-CUMS rats (p < 0.05 or p < 0.01). The abnormal elements in serum may cross blood-brain-barrier into the brain and induce oxidative stress, leading to ferroptosis. Furtherly, the expressions of ferroptosis-related protein including GPX4 and SLC7A11 were decreased in prefrontal cortex of OVX-CUMS rats (p < 0.01), which confirmed the above results. Quercetin treatment restored the above abnormal indicators (p < 0.05 or p < 0.01) induced by OVX-CUMS in rats. Our study suggested that quercetin regulated variation of elements in serum and prefrontal cortex, further inhibiting ferroptosis in prefrontal cortex through alleviating oxidative stress in OVX-CUMS rats.

Cyanocobalamin-loaded dissolving microneedles diminish skin inflammation in vivo

Inflammatory diseases of the skin have a considerable high prevalence worldwide and negatively impact the patients' quality of life. First-line standard therapies for these conditions inherently entail important side effects when used long-term, particularly complicating the management of chronic cases. Therefore, there is a need to develop novel therapeutic strategies to offer reliable alternative treatments. Abnormally high reactive oxygen species (ROS) levels are characteristic of this kind of illnesses, and therefore a reasonable therapeutic goal. Cyanocobalamin, also known as Vitamin B12, possesses notable antioxidant and ROS-scavenging properties which could make it a possible therapeutic alternative. However, its considerable molecular weight restricts passive diffusion through the skin and forces the use of an advanced transdermal delivery system. Here, we present several prototypes of Cyanocobalamin-loaded Dissolving Microarray Patches (B12@DMAPs) with adequate mechanical properties to effectively penetrate the stratum corneum barrier, allowing drug deposition into the skin structure. Ex vivo penetration and permeability studies noted an effective drug presence within the dermal skin layers; in vitro compatibility studies in representative cell skin cell lines such as L929 fibroblasts and HaCaT keratinocytes ensured their safe use. The in vivo efficacy of the selected prototype was tested in a delayed-type hypersensitivity murine model that mimics an inflammatory skin process. Several findings such as a reduction of MPO-related photon emission in a bioluminescence study, protection against histological damage, and decrease of inflammatory cytokines levels point out the effectivity of B12@DMAPs to downregulate the skin inflammatory environment. Overall, B12@DMAPs offer a cost-effective translational alternative for improving patients' skin healthcare.

The Protective Effects of Vitamin B Complex on Diclofenac Sodium-Induced Nephrotoxicity: The Role of NOX4/RhoA/ROCK

Diclofenac sodium (DIC) is a widely used non-steroidal anti-inflammatory drug. Unfortunately, its prolonged use is associated with nephrotoxicity due to oxidative stress, inflammation, and fibrosis. We aimed to investigate the nephroprotective effects of vitamin B complex (B1, B6, B12) against DIC-induced nephrotoxicity and its impact on NOX4/RhoA/ROCK, a pathway that plays a vital role in renal pathophysiology. Thirty-two Wistar rats were divided into four groups: (1) normal control; (2) vitamin B complex (16 mg/kg B1, 16 mg/kg B6, 0.16 mg/kg B12, intraperitoneal); (3) DIC (10 mg/kg, intramuscular); and (4) DIC plus vitamin B complex group. After 14 days, the following were assayed: serum renal biomarkers (creatinine, blood urea nitrogen, kidney injury molecule-1), oxidative stress, inflammatory (tumor necrosis factor-α, interleukin-6), and fibrotic (transforming growth factor-β) markers as well as the protein levels of NOX4, RhoA, and ROCK. Structural changes, inflammatory cell infiltration, and fibrosis were detected using hematoxylin and eosin and Masson trichrome stains. Compared to DIC, vitamin B complex significantly decreased the renal function biomarkers, markers of oxidative stress and inflammation, and fibrotic cytokines. Glomerular and tubular damage, inflammatory infiltration, and excessive collagen accumulation were also reduced. Protein levels of NOX4, RhoA, and ROCK were significantly elevated by DIC, and this elevation was ameliorated by vitamin B complex. In conclusion, vitamin B complex administration could be a renoprotective approach during treatment with DIC via, at least in part, suppressing the NOX4/RhoA/ROCK pathway.

Vitamin B12 Protects against Genotoxicity Induced by Cisplatin

BACKGROUND

Cisplatin is an effective synthetic chemotherapeutic drug used for cancer treatment. Vitamin B12 has been shown to possess anti-genotoxic activity. This study aimed to investigate the effect of vitamin B12 on chromosomal damage induced by cisplatin.

METHODS

The level of sister chromatid exchanges (SCEs) and chromosomal aberrations (CAs) were measured in cultured human blood lymphocytes treated with cisplatin and/or vitamin B12.

RESULTS

The results showed a significantly elevated frequency of CAs and SCEs of cisplatin-treated cultures compared to the control (P < 0.05). The CAs and SCEs induced by cisplatin were significantly lowered by pretreatment of cell cultures with vitamin B12. In addition, cisplatin caused a slight reduction in the mitotic index (MI), while vitamin B12 did not modulate the effect of cisplatin on MI.

CONCLUSION

Vitamin B12 can protect human lymphocytes against genotoxicity associated with cisplatin.

Vitamin B12 blocked Trypanosoma brucei rhodesiense-driven disruption of the blood brain barrier, and normalized nitric oxide and malondialdehyde levels in a mouse model

Infection with Trypanosoma brucei rhodesiense (T.b.r) causes acute Human African Trypanosomiasis (HAT) in Africa. This study determined the effect of vitamin B12 on T.b.r -driven pathological events in a mouse model. Mice were randomly assigned into four groups; group one was the control. Group two was infected with T.b.r; group three was supplemented with 8 mg/kg vitamin B12 for two weeks; before infection with T.b.r. For group four, administration of vitamin B12 was started from the 4th days post-infection with T.b.r. At 40 days post-infection, the mice were sacrificed to obtain blood, tissues, and organs for various analyses. The results showed that vitamin B12 administration enhanced the survival rate of T.b.r infected mice, and prevented T.b.r-induced disruption of the blood-brain barrier and decline in neurological performance. Notably, T.b.r-induced hematological alteration leading to anaemia, leukocytosis and dyslipidemia was alleviated by vitamin B12. T.b.r-induced elevation of the liver alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase and total bilirubin as well as the kidney damage markers urea, uric acid and creatinine were attenuated by vitamin B12. Vitamin B12 blocked T.b.r-driven rise in TNF-α and IFN-γ, nitric oxide and malondialdehyde. T.b.r-induced depletion of GSH levels were attenuated in the presence of vitamin B12 in the brain, spleen and liver tissues; a clear indication of the antioxidant activity of vitamin B12. In conclusion, treatment with vitamin B12 potentially protects against various pathological events associated with severe late-stage HAT and presents a great opportunity for further scrutiny to develop an adjunct therapy for severe late-stage HAT.

Vitamin B12-Multifaceted In Vivo Functions and In Vitro Applications

Vitamin B12 plays a key role in DNA stability. Research indicates that vitamin B12 deficiency leads to indirect DNA damage, and vitamin B12 supplementation may reverse this effect. Vitamin B12 acts as a cofactor for enzymes such as methionine synthase and methylmalonyl-CoA mutase, which are involved in DNA methylation and nucleotide synthesis. These processes are essential for DNA replication and transcription, and any impairment can result in genetic instability. In addition, vitamin B12 has antioxidant properties that help protect DNA from damage caused by reactive oxygen species. This protection is achieved by scavenging free radicals and reducing oxidative stress. In addition to their protective functions, cobalamins can also generate DNA-damaging radicals in vitro that can be useful in scientific research. Research is also being conducted on the use of vitamin B12 in medicine as vectors for xenobiotics. In summary, vitamin B12 is an essential micronutrient that plays a vital role in DNA stability. It acts as a cofactor for enzymes involved in the synthesis of nucleotides, has antioxidant properties and has potential value as a generator of DNA-damaging radicals and drug transporters.

Assessment of Oxidant and Antioxidant Status in Prepubertal Children following Vegetarian and Omnivorous Diets

Oxidant-antioxidant balance is crucial for maintaining one’s health, and the diet is possibly one of the most important factors affecting this balance. Therefore, the aim of this study was to determine the oxidant-antioxidant balance in children on a lacto-ovo-vegetarian diet. The study was conducted between January 2020 and December 2021. The concentrations of total oxidant capacity (TOC), total antioxidant capacity (TAC), reduced (GSH), and oxidized (GSSG) glutathione, as well as C-reactive protein (CRP) and calprotectin were measured in serum samples of 72 healthy prepubertal children (32 vegetarians and 40 omnivores). The oxidative stress index (OSI) and the GSH/GSSG ratio (R-index) were calculated. Children on a vegetarian diet had significantly lower median values of TOC, GSH, and GSSG, and higher TAC compared with the omnivores. OSI was significantly lower in vegetarians, while R-index, as well as median values of CRP and calprotectin did not differ between both groups of children. Significant negative correlations were observed between TOC and TAC levels in the whole group of children and in vegetarians. GSH and GSSG levels correlated positively in the groups of vegetarians, omnivores, and in all the children. There were significant positive correlations between TOC and GSH, as well as GSSG levels in all the studied groups of children. Our study results suggest that the vegetarian model of nutrition allows to maintain the oxidant-antioxidant balance in the serum of prepubertal children.

Vitamin B12 administration prevents ethanol-induced learning and memory impairment through re-establishment of the brain oxidant/antioxidant balance, enhancement of BDNF and suppression of GFAP

There are growing evidence indicating that the adolescent brain is persistently affected by the use of psychostimulant agents. In this regard, alcohol drinking has become rather common among the adolescents in many societies during the last decade. It is currently well known that long-term ethanol exposure deteriorates various cognitive functions such as learning and memory. Mechanistically, these adverse effects have been shown to be mediated by oxidative damage to central nervous system. On the other hand, Vit-B12 is known to improve cognitive performance by suppression of oxidative parameters. Thus, in the present study we aimed to test whether treatment by Vit-B12 could prevent ethanol-induced complications in mice using behavioral and biochemical methods. Different groups of male Syrian mice received ethanol, ethanol+Vit-B12, Vit-B12 alone, or saline during adolescence and then learning and memory functions were assessed by Morris water maze (MWM) and Passive Avoidance (PA) tests. Finally, mice were sacrificed for measurement of biochemical factors. Results indicated that, adolescent ethanol intake impairs learning and memory function through exacerbation of oxidative stress and Vit-B12 treatment improves these complications by re-establishment of oxidant/anti-oxidant balance in CNS. Moreover, we found that Vit-B12 prevents ethanol-induced reduction of BDNF and enhancement of GFAP and acetylcholinesterase (AChE) activity. In conclusion, it seems that Vit-B12 supplementation could be used as an effective therapeutic strategy to prevent learning and memory defects induced by chronic alcohol intake during adolescence.

Evaluation of thiol disulfide balance in adolescents with vitamin B12 deficiency

BACKGROUND

Vitamin B12 is an important vitamin for metabolism and affects many mechanisms in the body including neuronal migration, DNA synthesis, neurotransmitter synthesis, brain and cognitive development. Increased oxidative stress in the body leads to the damage of the child development, but also plays a crucial role in the pathogenesis of many diseases encountered in the childhood period. Our aim is to investigate whether or not B12 deficiency is associated with dynamic thiol/disulfide homeostasis in adolescent patients.

METHODS

This is a case-controlled observational study consisting of 45 adolescent patients with vitamin b12 deficiency and a control group consisting of 45 healthy adolescent. Patients between 11 and 18 ages who applied to the outpatient clinic for the first time with one of the complaints of headache were selected due to their decreased school performance, dizziness, and fatigue. Hemogram, vitamin B12, homocysteine levels and oxidative stress parameters such as native and total thiol disulfide levels and ratios of disulfide/native thiol, disulfide/total thiol, and native thiol/total thiol were measured from the patients.

RESULTS

Vitamin B12 level was found to be significantly lower in vitamin B12 deficiency group (p < 0.001). The serum disulfide level was found to be 27.5 ± 8.38 in the case group and 20.5 ± 8.36 in the control group (p < 0.001). In the multiple linear regression analysis, it was determined that the independent variables of native thiol, homocysteine and disulfide levels effected of vitamin B12 levels (p < 0.001, p < 0.001, p < 0.005 respectively; R² = 0.62).

CONCLUSION

The results obtained in terms of the effect of vitamin B12 deficiency on oxidative stress in adolescents are remarkable. The increase in oxidative stress parameters in the patient group may also suggest that oxidative stress plays a vital role in vitamin B12 deficiency in adolescence.

Reduction of Genotoxicity of Carbamazepine to Human Lymphocytes by Pre-treatment with Vitamin B12

BACKGROUND

Carbamazepine (CBZ) is widely used as an anti-epileptic drug. Vitamin B12 has been shown to protect against DNA damage caused by several mutagenic agents.

OBJECTIVE

This study aimed to investigate the effect of vitamin B12 on CBZ-induced genotoxicity in cultured human lymphocytes.

METHODS

Sister chromatid exchanges (SCEs) and chromosomal aberrations (CAs) genotoxic assays were utilized to achieve the study objective.

RESULTS

The results showed significantly higher frequencies of CAs and SCEs in the CBZ-treated cultures (12 μg/mL) compared to the control group (P<0.01). The genotoxic effects of CBZ were reduced by pre-treatment of cultures with vitamin B12 (13.5μg/ml, P<0.05). Neither CBZ nor vitamin B-12 showed any effects on mitotic and proliferative indices.

CONCLUSION

CBZ is genotoxic to lymphocyte cells, and this genotoxicity can be reduced by vitamin B12.

Beneficial effects of vitamin B12 treatment in pediatric patients diagnosed with vitamin B12 deficiency regarding total-native thiol, oxidative stress, and mononuclear leukocyte DNA damage

Vitamin B₁₂ is involved in biochemical metabolic pathways. B₁₂ deficiency is common in childhood when the need for the vitamin increases and growth and development occur. Various hematological, neurological, psychiatric, and gastrointestinal disorders are observed in its deficiency. In addition, B₁₂ deficiency is associated with oxidative stress and DNA damage. Therefore, the aim of our study is to evaluate oxidative stress, thiol/disulfide homeostasis, and DNA damage pre and post-treatment in children diagnosed with B₁₂ deficiency. A total of 40 children with B₁₂ deficiency were included in the study after the consent form was approved. Blood was drawn from children pre and posttreatment. Hemoglobin (HGB), hematocrit (HCT), and red blood cells (RBC) were measured by autoanalyzer; total antioxidant status (TAS), total oxidant status (TOS), total thiol (TT), and native thiol (NT) were measured by the photometric method, and DNA damage was analyzed by the comet assay method. Oxidative stress index (OSI) and disulfide (DIS) values were calculated. As a result of the experiments, HGB, HCT, and RBC increased with treatment. While TAS, TT, and NT as antioxidant parameters increased; TOS, OSI, and DIS decreased with treatment compared to pretreatment. DNA damage was also found to decrease with treatment. Additionally, these data were statistically significant (p < 0.001). It was found that oxidative stress and DNA damage decreased with oral B₁₂ treatment in children with B₁₂ deficiency, and clinical parameters were also improved.

Low vitamin B12 level in relation to trace element, total sialic acid and antioxidant enzymes in children with vitamin B12 deficiency anemia

In this study, children with vitamin B₁₂ deficiency anemia (V-B₁₂DA) and control subjects were evaluated for erythrocyte glutathione peroxidase, catalase and superoxide dismutase enzyme activities, glutathione, malondialdehyde, serum total sialic acid, total antioxidant status, cobalt, chromium, copper, selenium, vanadium, zinc, iron, lead, magnesium, calcium, sodium, potassium, chloride, phosphorus levels, and the associations of these variables were assessed. The study included 50 children with V-B₁₂DA and 50 control subjects. It was found that the V-B₁₂DA group was significantly lower than the control group, with regard to the mean±the standard error of the mean levels of cobalt (0.089±0.009; 0.058±0.0063 μmol/L, p<0.01), selenium (2.19±0.087; 1.88±0.057 μmol/L, p<0.01), vanadium (1.31±0.053; 1.18±0.035 μmol/L, p<0.05), magnesium (3.02±0.15; 2.73±0.068 μmol/L, p<0.05), zinc (50.76±1.96; 42.23± 1.53 μmol/L, p<0.001), and vitamin B₁₂ (427.20±21.45; 157.08±3.96 pg/mL, p<0.001). Moreover, a significant elevation in total sialic acid (1.44±0.050; 1.61±0.043 mmol/L, p<0.01), and mean corpuscular volume (MCV) (75.37±0.95; 79.91±1.14 fL, p<0.01). It was observed that in the V-B₁₂DA, significantly linear correlations were observed between cobalt - vitamin B₁₂ (r=0.334; p=0.025), vanadium - MCV (r=0.315; p=0.017), vitamin B₁₂ - MCV (r=-0.297; p=0.026). The findings of the study indicated that the levels of cobalt, vanadium significantly associated with traditional vitamin B_12-deficiency parameters. Vitamin B₁₂ and MCV should be measured together with cobalt, vanadium for monitoring the vitamin B₁₂ deficiency anemia.

Effects of quercetin on the alterations of serum elements in chronic unpredictable mild stress-induced depressed rats

Depression is a common and serious psychiatric disorder, but current conventional antidepressants have limited efficacy and significant side effects. Thus, better antidepressants are urgently needed. This study aimed to investigate the antidepressant-like effects and potential mechanism of quercetin by evaluating the changes of serum elements in chronic unpredictable mild stress (CUMS) rats. Based on the results of the sucrose preference test (SPT), 96 rats were randomly assigned to six groups: control, different dosages of quercetin (10 and 50 mg/kg·bw, respectively), depressed, and different dosages quercetin plus depressed groups. After 8 weeks of CUMS modeling, rat serum was collected. Fifteen elements in serum were analyzed by inductively coupled plasma mass spectrometry (ICP-MS), and related enzyme indicators, antioxidant indicators, and inflammatory cytokines were detected to further explore the potential mechanism. Besides, the accuracy and precision of the method were evaluated. The results showed that the levels of iron (Fe), copper (Cu), and calcium (Ca) in serum significantly increased (p ≤ 0.001), while the levels of magnesium (Mg), zinc (Zn), selenium (Se), and cobalt (Co) significantly decreased (p ≤ 0.001) in depressed group compared with the control group. The levels of the remaining eight elements did not change significantly. When high-dose quercetin was administered to depressed rats, the levels of the above seven elements significantly restored (p ≤ 0.001). This study suggests that quercetin (50 mg/kg·bw) has a regulatory effect on serum elements in CUMS rats, which may be mediated by reducing oxidative stress, inhibiting inflammation, and regulating a variety of neurotransmitter systems.

Morphological evaluation of the effects of exercise on high-fat-diet-induced liver damage in rats

BACKGROUND/AIMS

This study was aimed to investigate the protective effects of swimming exercise on nonalcoholic fatty liver disease (NAFLD) associated with high fat diet-induced obesity, using microscopical and biochemical parameters.

MATERIALS AND METHODS

Sprague Dawley male rats were fed either standard chow (STD group; 6% fat) or high-fat diet (HFD group; 45% fat) for 18 weeks. Animals were divided into four groups, STD, STD + EXC, HFD, HFD + EXC. Exercise groups were submitted to swimming training 5 days of week and 1h of per day, during the last 6 weeks of the experiment. At the end of the experiment, liver samples were evaluated for morphologically and ultrastructurally. Moreover, malondialdehyde (MDA) and glutathione (GSH) levels were evaluated in liver samples.

RESULTS

Normal morphology of liver parancyma with hepatocytes and sinusoids was observed in the STD and STD+EXC groups. Steatosis, lipid accumulation, ballooned hepatocytes, decrease of glycogen deposits and fibrosis in periportal area were observed in HFD group. Liver MDA level was increased and GSH level was decreased in HFD group. Exercise treatment ameliorated these morphological and oxidative changes in HFD induced liver damage.

CONCLUSION

Based on morphological and biochemical analysis, we could conclude that swimming training ameliorated obesity-induced liver damage by regulating lipid accumulation and oxidative damage.

Higher vitamin B12 levels in neurodevelopmental disorders than in healthy controls and schizophrenia: A comparison among participants between 2 and 53 years

Recent studies suggest that both high and low levels of vitamin B12 (vitB12) may have negative health impacts. We measured VitB12 in patients with the Neurodevelopmental disorders (ND) (n = 222), comprised of Autism Spectrum Disorders, specific Developmental disorders, and Intellectual Disability (aged 2-53 years), schizophrenia (n = 401), and healthy controls (HC) (n = 483). Age-and gender-adjusted vitB12 z-scores were calculated by comparisons with a reference population (n = 76 148). We found higher vitB12 in ND (median 420 pmol/L, mean z-score: 0.30) than in HC (316 pmol/L, z-score: 0.06, P < .01) and schizophrenia (306 pmol/L, z-score: -0.02, P < .001), which was significant after adjusting for age, gender, vitB12 supplement, folate, hemoglobin, leukocytes, liver, and kidney function (P < .02). In ND, 20% (n = 44) had vitB12 above 650 pmol/L, and 1% (n = 3) had below 150 pmol/L (common reference limits). In 6.3% (n = 14) of ND, vitB12 was above 2SD of mean in the age-and gender-adjusted reference population, which was more frequent than in HC (n = 8, 1.6%), OR: 4.0, P = .001. Low vitB12 was equally frequent as in HC, and vitB12 z-scores were equal across the age groups. To conclude, vitB12 was higher in ND than in HC and schizophrenia, suggesting a specific feature of ND, which warrants further studies to investigate the underlying mechanisms.

Astrocyte activation following nitrous oxide exposure is related to oxidative stress and glutamate excitotoxicity

BACKGROUND AND AIMS

Nitrous oxide is commonly used as an anesthetic agent and its exposure produces prolonged inactivation of vitamin B12. Nitrous oxide toxicity is associated with central nervous system changes which are similar to sub-acute combined degeneration (SACD). Astrocytes have important role in neurotoxic injuries, but have not been evaluated in N₂O toxicity. In the present study, we have evaluated the changes in astrocytes in N₂O exposed rats and correlated with neurobehavioral changes, oxidative stress and glutamate level.

MATERIAL AND METHODS

Adult wistar male rats were exposed to N₂O oxygen mixture in 1:1 ratio at a rate of 2 L/min for 120 min for 60 days. Control rats underwent similar exposure to oxygen. At the end of exposure, spontaneous locomotor activities (total distance travelled, time resting, time moving, number of rearing, stereotypic count) and grip strength were evaluated. Plasma glutathione (GSH), total antioxidant capacity (TAC), serum malonodialdehyde (MDA) and serum homocysteine (Hcy) were measured by spectrophotometer. Glutamate in the cerebral cortex and cerebellum were measured by colorimetry. Immunohistochemistry for astrocyte (GFAP) phenotypic analysis and its activation in brain and spinal cord were measured using image J software in N₂O exposed and control rats.

RESULTS

The N₂O exposed rats had significant reduction in total distance travelled, time moving and number of rearing whereas time resting increased compared to the control rats. Hcy, glutamate and MDA levels were significantly increased, however GSH and TAC level decreased in N₂O exposed group compared to the controls. Astrocyte phenotype and its activation was significantly altered more so in spinal cord compared to cerebral cortex and was associated with neurobehavioral changes, oxidative stress and glutamate level.

CONCLUSIONS

N₂O related clinical dysfunction may be related to changes in astrocyte activation which is related to oxidative stress and glutamate neurotoxicity.

Interaction of serum vitamin B12 and folate with MTHFR genotypes on risk of ischemic stroke

OBJECTIVE

We evaluated the interaction of serum folate and vitamin B₁₂ with methylenetetrahydrofolate reductase (MTHFR) C677T genotypes on the risk of first ischemic stroke and on the efficacy of folic acid treatment in prevention of first ischemic stroke.

METHODS

A total of 20,702 hypertensive adults were randomized to a double-blind treatment of daily enalapril 10 mg and folic acid 0.8 mg or enalapril 10 mg alone. Participants were followed up every 3 months.

RESULTS

Median values of folate and B₁₂ concentrations at baseline were 8.1 ng/mL and 280.2 pmol/L, respectively. Over a median of 4.5 years, among those not receiving folic acid, participants with baseline serum B₁₂ or serum folate above the median had a significantly lower risk of first ischemic stroke (hazard ratio [HR], 0.74; 95% confidence interval [CI], 0.57-0.96), especially in those with MTHFR 677 CC genotype (wild-type) (HR, 0.49; 95% CI, 0.31-0.78). Folic acid treatment significantly reduced the risk of first ischemic stroke in participants with both folate and B₁₂ below the median (2.3% in enalapril-folic acid group vs 3.6% in enalapril-only group; HR, 0.62; 95% CI, 0.46-0.86), particularly in MTHFR 677 CC carriers (1.6% vs 4.9%; HR, 0.24; 95% CI, 0.11-0.55). However, TT homozygotes responded better with both folate and B₁₂ levels above the median (HR, 0.28; 95% CI, 0.10-0.75).

CONCLUSIONS

The risk of first ischemic stroke was significantly higher in hypertensive patients with low levels of both folate and B₁₂. Effect of folic acid treatment was greatest in patients with low folate and B₁₂ with the CC genotype, and with high folate and B₁₂ with the TT genotype.

The Effect of Chronic Cerebral Hypoperfusion on Blood-Brain Barrier Permeability in a Transgenic Alzheimer's Disease Mouse Model (PS1V97L)

The blood-brain barrier (BBB) can restrict the therapeutic effects of Alzheimer's disease (AD) medications. While a large number of AD drug treatment trials targeting BBB dynamics have emerged, most have failed due to insufficient permeability. Furthermore, a subset of AD cases, which also feature chronic hypoperfusion are complicated by BBB deficits. We used a mouse model of AD with chronic hypoperfusion-transgenic mice (PS1V97L) with right common carotid artery ligation. In this model, we assessed how chronic cerebral hypoperfusion changed the pathophysiological processes that increase BBB permeability. Compared with control mice, AD mice with chronic hypoperfusion revealed significantly upregulated expression of the receptor for advanced glycation end products (RAGE) on the BBB. Upregulated RAGE caused increased accumulation of amyloid-β (Aβ) in the brain in these mice. Upregulation of RAGE (or binding to Aβ) can promote activation of the NF-κB pathway and enhance oxidative stress and increase the release of pro-inflammatory factors. These factors promoted the reduction of tight junction proteins between the endothelial cells in the BBB and increased its permeability. These findings suggest that the transporter RAGE dysregulation on the BBB initiates a series of pathophysiological processes which lead to increased BBB permeability. Taken together, we have shown that chronic hypoperfusion can serve to enhance and aggravate the BBB impairment in AD.

Serum and Dietary Folate and Vitamin B12 Levels Account for Differences in Cellular Aging: Evidence Based on Telomere Findings in 5581 U.S. Adults

Folate and vitamin B₁₂ are essential for a variety of metabolic processes. Both micronutrients have been shown to reduce oxidative stress significantly. The present cross-sectional investigation evaluated the association between serum and dietary folate and vitamin B₁₂ levels and leukocyte telomere length, an index of cellular aging influenced by oxidative stress. The study included 5581 adults from the National Health and Nutrition Examination Survey (NHANES). Because participants were randomly selected, results are generalizable to all civilian, noninstitutionalized U.S. adults. A blood draw provided DNA and serum folate and B₁₂ information. The quantitative polymerase chain reaction method was used to measure telomere length. The Bio-Rad Quantaphase II folate and vitamin B₁₂ radioassay kit was used to quantify levels of folate and vitamin B₁₂. Dietary folate and vitamin B₁₂ were assessed using a multipass 24 h recall. In some models, age, race, smoking pack-years, alcohol use, body mass index, total physical activity, hours fasted before the blood draw, and diabetes status were employed as covariates to minimize their influence. Findings showed that for each additional year of chronological age, telomeres were 15.6 base pairs shorter, on average (F = 378.8, p < 0.0001). Men had shorter telomeres than women after adjusting for all the covariates (F = 6.8, p = 0.0146). Serum (F = 10.5, p = 0.0030) and dietary (F = 5.0, p = 0.0325) folate concentrations were each linearly related to telomere length in women, but not in men, after controlling for age and race. Serum vitamin B₁₂ and telomere length had a nonsignificant, inverse relationship in women, with age and race controlled (F = 2.8, p = 0.1056), but no relation in men. Dietary vitamin B₁₂ was linearly related to telomere length in women, after adjusting for age and race (F = 4.3, p = 0.0468), but not in men. Overall, evidence indicates that folate and vitamin B₁₂ levels, especially folate, account for meaningful differences in cell aging in women, but not in men.

A Review of Dietary (Phyto)Nutrients for Glutathione Support

Glutathione is a tripeptide that plays a pivotal role in critical physiological processes resulting in effects relevant to diverse disease pathophysiology such as maintenance of redox balance, reduction of oxidative stress, enhancement of metabolic detoxification, and regulation of immune system function. The diverse roles of glutathione in physiology are relevant to a considerable body of evidence suggesting that glutathione status may be an important biomarker and treatment target in various chronic, age-related diseases. Yet, proper personalized balance in the individual is key as well as a better understanding of antioxidants and redox balance. Optimizing glutathione levels has been proposed as a strategy for health promotion and disease prevention, although clear, causal relationships between glutathione status and disease risk or treatment remain to be clarified. Nonetheless, human clinical research suggests that nutritional interventions, including amino acids, vitamins, minerals, phytochemicals, and foods can have important effects on circulating glutathione which may translate to clinical benefit. Importantly, genetic variation is a modifier of glutathione status and influences response to nutritional factors that impact glutathione levels. This narrative review explores clinical evidence for nutritional strategies that could be used to improve glutathione status.

Vitamin B12 in Relation to Oxidative Stress: A Systematic Review

The triage theory posits that modest micronutrient deficiencies may induce reallocation of nutrients to processes necessary for immediate survival at the expense of long-term health. Neglected processes could in time contribute to the onset of age-related diseases, in which oxidative stress is believed to be a major factor. Vitamin B12 (B12) appears to possess antioxidant properties. This review aims to summarise the potential antioxidant mechanisms of B12 and investigate B12 status in relation to oxidative stress markers. A systematic query-based search of PubMed was performed to identify eligible publications. The potential antioxidant properties of B12 include: (1) direct scavenging of reactive oxygen species (ROS), particularly superoxide; (2) indirect stimulation of ROS scavenging by preservation of glutathione; (3) modulation of cytokine and growth factor production to offer protection from immune response-induced oxidative stress; (4) reduction of homocysteine-induced oxidative stress; and (5) reduction of oxidative stress caused by advanced glycation end products. Some evidence appears to suggest that lower B12 status is related to increased pro-oxidant and decreased antioxidant status, both overall and for subclinically deficient individuals compared to those with normal B12 status. However, there is a lack of randomised controlled trials and prospective studies focusing specifically on the relation between B12 and oxidative stress in humans, resulting in a low strength of evidence. Further work is warranted.

Mito-Nuclear Communication by Mitochondrial Metabolites and Its Regulation by B-Vitamins

Mitochondria are cellular organelles that control metabolic homeostasis and ATP generation, but also play an important role in other processes, like cell death decisions and immune signaling. Mitochondria produce a diverse array of metabolites that act in the mitochondria itself, but also function as signaling molecules to other parts of the cell. Communication of mitochondria with the nucleus by metabolites that are produced by the mitochondria provides the cells with a dynamic regulatory system that is able to respond to changing metabolic conditions. Dysregulation of the interplay between mitochondrial metabolites and the nucleus has been shown to play a role in disease etiology, such as cancer and type II diabetes. Multiple recent studies emphasize the crucial role of nutritional cofactors in regulating these metabolic networks. Since B-vitamins directly regulate mitochondrial metabolism, understanding the role of B-vitamins in mito-nuclear communication is relevant for therapeutic applications and optimal dietary lifestyle. In this review, we will highlight emerging concepts in mito-nuclear communication and will describe the role of B-vitamins in mitochondrial metabolite-mediated nuclear signaling.

Vitamin B12 Levels in Methamphetamine Addicts

Objective: It has been established that reduced vitamin B12 serum levels are associated with cognitive decline and mental illness. The chronic use of methamphetamine (MA), which is a highly addictive drug, can induce cognitive impairment and psychopathological symptoms. There are few studies addressing the association of MA with vitamin B12 serum levels. This study examined whether the serum levels of B12 are associated with MA addiction.

Methods: Serum vitamin B12, homocysteine (Hcy), glucose and triglyceride concentrations were measured in 123 MA addicts and 108 controls. In addition, data were collected on their age, marital status, level of education and Body Mass Index (BMI) for all participants. In the patient group, the data for each subject were collected using the Fagerstrom Test for Nicotine Dependence (FTND), the Alcohol Use Disorders Identification Test (AUDIT), and a drug use history, which included the age of onset, total duration of MA use, the number of relapses and addiction severity.

Results: Our results showed that MA addicts had lower vitamin B12 levels (p < 0.05) than those of healthy controls, but Hcy levels were not significantly different between the two groups (p > 0.05). Serum B12 levels were negatively correlated with the number of relapses in the MA group. Furthermore, binary logistics regression analysis indicated that the B12 was an influencing factor contributing to addiction severity.

Conclusion: The findings of this study suggest that some MA addicts might have vitamin B12 deficiency, and serum B12 levels may be involved in the prognosis of MA addiction.

Cobalamin Deficiency Results in Increased Production of Formate Secondary to Decreased Mitochondrial Oxidation of One-Carbon Units in Rats

Background

Formate is produced in mitochondria via the catabolism of serine, glycine, dimethylglycine, and sarcosine. Formate produced by mitochondria may be incorporated into the cytosolic folate pool where it can be used for important biosynthetic reactions. Previous studies from our lab have shown that cobalamin deficiency results in increased plasma formate concentrations.

Objective

Our goal was to determine the basis for elevated formate in vitamin B-12 deficiency.

Methods

Male Sprague Dawley rats were randomly assigned to consume either a cobalamin-replete (50 μg cobalamin/kg diet) or -deficient (no added cobalamin) diet for 6 wk. Formate production was measured in vivo and in isolated liver mitochondria from a variety of one-carbon precursors. We also measured the oxidation of [3-14C]-l-serine to 14CO2 in isolated rat liver mitochondria and the expression of hepatic genes involved in one-carbon unit and formate metabolism.

Results

Cobalamin-deficient rats produce formate at a rate 55% higher than that of replete rats. Formate production from serine was increased by 60% and from dimethylglycine and sarcosine by ∼200% in liver mitochondria isolated from cobalamin-deficient rats compared with cobalamin-replete rats. There was a 26% decrease in the 14CO2 produced by mitochondria from cobalamin-deficient rats. Gene expression analysis showed that 10-formyltetrahydrofolate dehydrogenase-cytosolic (Aldh1l1) and mitochondrial (Aldh1l2) expression were decreased by 40% and 60%, respectively, compared to control, while 10-formyltetrahydrofolate synthetase, mitochondrial, monofunctional (Mthfd1l) expression was unchanged.

Conclusion

We propose that a bifurcation in mitochondrial one-carbon metabolism is a key control mechanism in determining the fate of one-carbon units, to formate or CO2. During cobalamin deficiency in rats the disposition of 10-formyl-tetrahydrofolate carbon is shifted in favor of formate production. This may represent a mechanism to generate more one-carbon units for the replenishment of the S-adenosylmethionine pool which is depleted in this condition.

Redox imbalance correlates with high Nugent score in bacterial vaginosis

AIM

The main goal of this work was to highlight the significance of redox imbalance in the pathophysiology of bacterial vaginosis (BV). We studied the pro-oxidant (malondialdehyde) and antioxidants (glutathione, total antioxidant capacity) in the vaginal fluids of women and compared them on the basis of their Nugent score (NS).

METHODS

Women were clinically screened using Amsel criteria (≥2 were regarded as positive) and were further screened for NS on the basis of microscopic examination. Subjects were classified into one of three groups - healthy controls, intermediate, and BV - on the basis of NS (0-3, 4-6, and 7-10, respectively). High vaginal swabs were collected from the study participants in order to estimate the levels of pro and antioxidants in the vaginal fluids.

RESULTS

Our results indicated that levels of both pro- and antioxidants were elevated in high vaginal swabs of women in the intermediate (NS: 4-6) and BV (NS: 7-10) groups as compared to those of healthy control women. The difference in mean values for total antioxidant capacity and glutathione was found to be statistically significant. Furthermore, in the BV group (NS: ≥7) both antioxidants (glutathione and total antioxidant capacity) and the pro-oxidant, malondialdehyde, were found to be negatively correlated to NS. Interestingly, the correlation between NS and malondialdehyde was statistically significant.

CONCLUSION

Our results suggest a significant correlation between redox imbalance and NS, which signifies changes in vaginal ecology from normal flora (Lactobacillus spp.) towards a more mixed bacterial population representing BV.

Vitamin B12 among Vegetarians: Status, Assessment and Supplementation

Cobalamin is an essential molecule for humans. It acts as a cofactor in one-carbon transfers through methylation and molecular rearrangement. These functions take place in fatty acid, amino acid and nucleic acid metabolic pathways. The deficiency of vitamin B12 is clinically manifested in the blood and nervous system where the cobalamin plays a key role in cell replication and in fatty acid metabolism. Hypovitaminosis arises from inadequate absorption, from genetic defects that alter transport through the body, or from inadequate intake as a result of diet. With the growing adoption of vegetarian eating styles in Western countries, there is growing focus on whether diets that exclude animal foods are adequate. Since food availability in these countries is not a problem, and therefore plant foods are sufficiently adequate, the most delicate issue remains the contribution of cobalamin, which is poorly represented in plants. In this review, we will discuss the status of vitamin B12 among vegetarians, the diagnostic markers for the detection of cobalamin deficiency and appropriate sources for sufficient intake, through the description of the features and functions of vitamin B12 and its absorption mechanism.