Novel relationships between B12, folate and markers of inflammation, oxidative stress and NAD(H) levels, systemically and in the CNS of a healthy human cohort

The Effect of Vitamin B12 Supplementation on Leukocyte Telomere Length in Mildly Stunted Nepalese Children: A Secondary Outcome of a Randomized Controlled Trial

BACKGROUND

Vitamin B12 is essential for deoxyribonucleic acid synthesis and genome stability. A deficiency of vitamin B12 is associated with telomere shortening, genomic aging, and increased risk of chronic disease and mortality.

OBJECTIVES

The study aims to determine the effect of vitamin B12 supplementation on leukocyte telomere length (LTL) in infants at risk of vitamin B12 deficiency.

METHODS

The study was a predefined secondary analysis of a randomized controlled trial enrolling 600 Nepalese infants aged 6 -11 mo, who were supplemented with 2 μg (2-3 recommended daily allowances) vitamin B12 or placebo daily for 1 y. At the end of the study, LTL was measured in 497 participants. Mean LTL was compared between the treatment arms in the full sample and predefined subgroups based on markers of vitamin B12 status, hemoglobin, sex, and growth indices.

RESULTS

LTL at end-study did not differ between the vitamin B12 and placebo arm with a standardized mean difference (95% confidence interval) of 0.04 (-0.14, 0.21). There was no effect of vitamin B12 on LTL in any of the subgroups.

CONCLUSIONS

Providing daily vitamin B12 for 1 y during infancy in a population at risk of vitamin B12 deficiency does not affect LTL. This trial was registered at clinicaltrials.gov as NCT02272842.

Emerging Roles of Vitamin B12 in Aging and Inflammation

Vitamin B12 (cobalamin) is an essential nutrient for humans and animals. Metabolically active forms of B12-methylcobalamin and 5-deoxyadenosylcobalamin are cofactors for the enzymes methionine synthase and mitochondrial methylmalonyl-CoA mutase. Malfunction of these enzymes due to a scarcity of vitamin B12 leads to disturbance of one-carbon metabolism and impaired mitochondrial function. A significant fraction of the population (up to 20%) is deficient in vitamin B12, with a higher rate of deficiency among elderly people. B12 deficiency is associated with numerous hallmarks of aging at the cellular and organismal levels. Cellular senescence is characterized by high levels of DNA damage by metabolic abnormalities, increased mitochondrial dysfunction, and disturbance of epigenetic regulation. B12 deficiency could be responsible for or play a crucial part in these disorders. In this review, we focus on a comprehensive analysis of molecular mechanisms through which vitamin B12 influences aging. We review new data about how deficiency in vitamin B12 may accelerate cellular aging. Despite indications that vitamin B12 has an important role in health and healthy aging, knowledge of the influence of vitamin B12 on aging is still limited and requires further research.

Higher circulating vitamin B12 is associated with lower levels of inflammatory markers in individuals at high cardiovascular risk and in naturally aged mice

BACKGROUND

Vitamin B12 is an essential nutrient that is involved in numerous physiological processes, and its deficiency can lead to various complications, including neurological and haematological disorders. Some studies have suggested that vitamin B12 may have anti-inflammatory effects, but the mechanisms underlying this relationship are not yet fully understood. We investigated the relationship between circulating vitamin B12 and inflammatory markers interleukin (IL)-6 and C-reactive protein (CRP). The association of peripheral levels of vitamin B12 with IL-6 and CRP was assessed in 136 human samples from a high cardiovascular risk population. To corroborate the results from the human trial, the analysis was replicated in naturally aged mice.

RESULTS

Individuals with higher serum levels of vitamin B12 showed lower concentrations of IL-6 and CRP after adjustment for potential confounders, and an inverse association was also found between serum IL-6 and vitamin B12 levels in naturally aged mice.

CONCLUSION

Circulating vitamin B12 was inversely associated with IL-6 and CRP in humans and with IL-6 in mice, suggesting that it may exert an anti-inflammatory effect through modulation of these pro-inflammatory molecules. © 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Vitamin B12 Deficiency and the Nervous System: Beyond Metabolic Decompensation-Comparing Biological Models and Gaining New Insights into Molecular and Cellular Mechanisms

Vitamin B12 (VitB12) is a micronutrient and acts as a cofactor for fundamental biochemical reactions: the synthesis of succinyl-CoA from methylmalonyl-CoA and biotin, and the synthesis of methionine from folic acid and homocysteine. VitB12 deficiency can determine a wide range of diseases, including nervous system impairments. Although clinical evidence shows a direct role of VitB12 in neuronal homeostasis, the molecular mechanisms are yet to be characterized in depth. Earlier investigations focused on exploring the biochemical shifts resulting from a deficiency in the function of VitB12 as a coenzyme, while more recent studies propose a broader mechanism, encompassing changes at the molecular/cellular levels. Here, we explore existing study models employed to investigate the role of VitB12 in the nervous system, including the challenges inherent in replicating deficiency/supplementation in experimental settings. Moreover, we discuss the potential biochemical alterations and ensuing mechanisms that might be modified at the molecular/cellular level (such as epigenetic modifications or changes in lysosomal activity). We also address the role of VitB12 deficiency in initiating processes that contribute to nervous system deterioration, including ROS accumulation, inflammation, and demyelination. Consequently, a complex biological landscape emerges, requiring further investigative efforts to grasp the intricacies involved and identify potential therapeutic targets.

Folic acid deficiency exacerbates the inflammatory response of astrocytes after ischemia-reperfusion by enhancing the interaction between IL-6 and JAK-1/pSTAT3

AIM

To demonstrate the role of IL-6 and pSTAT3 in the inflammatory response to cerebral ischemia/reperfusion following folic acid deficiency (FD).

METHODS

The middle cerebral artery occlusion/reperfusion (MCAO/R) model was established in adult male Sprague-Dawley rats in vivo, and cultured primary astrocytes were exposed to oxygen-glucose deprivation/reoxygenation (OGD/R) to emulate ischemia/reperfusion injury in vitro.

RESULTS

Glial fibrillary acidic protein (GFAP) expression significantly increased in astrocytes of the brain cortex in the MCAO group compared to the SHAM group. Nevertheless, FD did not further promote GFAP expression in astrocytes of rat brain tissue after MCAO. This result was further confirmed in the OGD/R cellular model. In addition, FD did not promote the expressions of TNF-α and IL-1β but raised IL-6 (Peak at 12 h after MCAO) and pSTAT3 (Peak at 24 h after MCAO) levels in the affected cortices of MCAO rats. In the in vitro model, the levels of IL-6 and pSTAT3 in astrocytes were significantly reduced by treatment with Filgotinib (JAK-1 inhibitor) but not AG490 (JAK-2 inhibitor). Moreover, the suppression of IL-6 expression reduced FD-induced increases in pSTAT3 and pJAK-1. In turn, inhibited pSTAT3 expression also depressed the FD-mediated increase in IL-6 expression.

CONCLUSIONS

FD led to the overproduction of IL-6 and subsequently increased pSTAT3 levels via JAK-1 but not JAK-2, which further promoted increased IL-6 expression, thereby exacerbating the inflammatory response of primary astrocytes.

Central retinal vein occlusion post ChAdOx1 nCoV-19 vaccination - can it be explained by the two-hit hypothesis?

PURPOSE

To report a case of central retinal vein occlusion (CRVO) seven days following the first dose of ChAdOx1 nCoV-19 vaccine and propose a hypothesis for the possible underlying pathogenesis.

OBSERVATION

A 31-year-old male presented with CRVO with cystoid macular edema, one week after receiving his first ChAdOx1 nCoV-19 vaccine dose. Apart from mild hyperhomocysteinemia, no major thrombophilic or systemic risk factors were found. Anti-platelet factor 4 antibodies, specific for vaccine-induced immune thrombotic thrombocytopenia, were also negative. However, he tested strongly positive (> 250 U/mL) for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) IgG spike antibodies, 2 weeks post the first dose - suggestive of a prior subclinical infection.

CONCLUSION

COVID-19 is known to be associated with an altered host one-carbon metabolism resulting in hyperhomocysteinemia. We hypothesize that a prior subclinical infection with COVID-19, the first hit, may have led to hyperhomocysteinemia in our patient and vaccination must have been the second hit that triggered the thrombotic event. Further studies, including correlation of thrombotic complications with IgG antibody titres post-vaccination, are essential in order to better understand the pathogenesis of such events.

The protective mechanism of folic acid on hyperhomocysteinemia-related arterial injury in spontaneously hypertensive rats: Folic acid against arterial inflammation

BACKGROUND

Hypertension associated with hyperhomocysteinemia (HHcy) is correlated with a high risk of vascular diseases. Studies found that folic acid (FA) supplementation can reduce the risk of cardiovascular and cerebrovascular events. The aim of the present study was to explore the potential mechanisms of FA attenuating HHcy-related arterial injury in spontaneously hypertensive rats (SHRs).

METHODS

24 SHRs were randomized into the control group, the HHcy group, and the HHcy + FA group (8 per group). The SHRs in the HHcy group and the HHcy + FA group were given DL-Hcy intraperitoneally to mimic hypertension associated with HHcy. The SHRs in the HHcy + FA group were given FA by gavage to mimic an FA-fortified diet. The histopathology and immunohistochemistry of rat aorta and carotid artery were analyzed, and the relative expression levels of immune/inflammation and oxidative stress molecules in arterial tissue were detected by quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot.

RESULTS

FA significantly reduced the expression levels of nuclear factor-κ-gene binding (NF-κB) p65/Rela and interleukin-6 (IL-6) in rat arterial tissues, as well as the levels of plasma HHcy and serum malondialdehyde (MDA) in hypertension associated with HHcy rats (p < 0.05). At the same time, FA significantly increased the serum superoxide dismutase (SOD) level in hypertension associated with HHcy rats, and even the SOD level of the HHcy + FA group was higher than that of the control group (p < 0.05). However, HHcy induced the opposite results of the above indicators in SHRs compared with the control group (p < 0.05).

CONCLUSIONS

The arterial protection mechanisms of FA are related to reducing the concentration of HHcy to eliminate the tissue toxicity of HHcy, inhibiting NF-κBp65/Rela/IL-6 pathway molecules to regulate inflammatory response, and promoting the potential anti-oxidative stress pathway molecules to reduce oxidative stress level.

Distinct effects of interleukin-6 and interferon-γ on differentiating human cortical neurons

Translational evidence suggests that cytokines involved in maternal immune activation (MIA), such as interleukin-6 (IL-6) and interferon-γ (IFN-γ), can cross the placenta, injure fetal brain, and predispose to neuropsychiatric disorders. To elaborate developmental neuronal sequelae of MIA, we differentiated human pluripotent stem cells to cortical neurons over a two-month period, exposing them to IL-6 or IFN-γ. IL-6 impacted expression of genes regulating extracellular matrix, actin cytoskeleton and TGF-β signaling while IFN-γ impacted genes regulating antigen processing, major histocompatibility complex and endoplasmic reticulum biology. IL-6, but not IFN-γ, altered mitochondrial respiration while IFN-γ, but not IL-6, induced reduction in dendritic spine density. Pre-treatment with folic acid, which has known neuroprotective and anti-inflammatory properties, ameliorated IL-6 effects on mitochondrial respiration and IFN-γ effects on dendritic spine density. These findings suggest distinct mechanisms for how fetal IL-6 and IFN-γ exposure influence risk for neuropsychiatric disorders, and how folic acid can mitigate such risk.

Inverse Association of Serum Folate Level with Metabolic Syndrome and Its Components in Korean Premenopausal Women: Findings of the 2016–2018 Korean National Health Nutrition Examination Survey

Research on the association of serum folate levels with metabolic syndrome (MetS) in premenopausal women is lacking. This study was aimed to investigate this association in 1730 premenopausal women using the 2016 to 2018 Korean National Health and Nutrition Examination Survey data. Participants’ mean age and BMI were 35.9 years and 22.7 kg/m2, respectively. Participants were divided into three groups according to serum folate tertiles. Odds ratios (OR) and 95% confidence intervals (CIs) for abdominal obesity, elevated blood pressure (BP), high fasting plasma glucose (FPG), high triglycerides (TG), low high-density lipoprotein cholesterol (HDL-C), and MetS were calculated in multiple logistic regression models adjusted for possible confounders, by serum folate level tertiles. Prevalence of MetS (14.9, 11.0, and 8.6%); abdominal obesity (17.8, 16.0, and 11.4%); high TG (17.5, 14.0, and 11.1%); and low HDL-C (50.3, 44.6, and 42.5%) decreased with increasing folate level tertile. Prevalence of elevated BP (14.3, 12.0, and 11.7%) and high FPG (11.9, 15.8, and 13.0%) showed no significant differences according to serum folate level tertiles. The multivariate-adjusted ORs (95% CIs) for MetS, abdominal obesity, elevated BP, high TG, and low HDL-C in the highest folate level tertile were 2.17 (1.46–3.22), 1.80 (1.25–2.60), 1.77 (1.16–2.70), 1.90 (1.35–2.67), and 1.49 (1.14–1.94), respectively. The ORs for high FPG did not show significant differences according to serum folate level tertiles. In conclusion, serum folate levels were inversely associated with an increased risk of MetS in Korean premenopausal women. These results suggest that MetS can be prevented and managed by improving the serum folate levels in premenopausal women.

The role of vitamin B12 in viral infections: a comprehensive review of its relationship with the muscle-gut-brain axis and implications for SARS-CoV-2 infection

This comprehensive review establishes the role of vitamin B12 as adjunct therapy for viral infections in the treatment and persistent symptoms of COVID-19, focusing on symptoms related to the muscle-gut-brain axis. Vitamin B12 can help balance immune responses to better fight viral infections. Furthermore, data from randomized clinical trials and meta-analysis indicate that vitamin B12 in the forms of methylcobalamin and cyanocobalamin may increase serum vitamin B12 levels, and resulted in decreased serum methylmalonic acid and homocysteine concentrations, and decreased pain intensity, memory loss, and impaired concentration. Among studies, there is much variation in vitamin B12 doses, chemical forms, supplementation time, and administration routes. Larger randomized clinical trials of vitamin B12 supplementation and analysis of markers such as total vitamin B12, holotranscobalamin, total homocysteine and methylmalonic acid, total folic acid, and, if possible, polymorphisms and methylation of genes need to be conducted with people with and without COVID-19 or who have had COVID-19 to facilitate the proper vitamin B12 form to be administered in individual treatment.

Maternal Diet, Infection, and Risk of Cord Blood Inflammation in the Bangladesh Projahnmo Pregnancy Cohort

Inflammation may adversely affect early human brain development. We aimed to assess the role of maternal nutrition and infections on cord blood inflammation. In a pregnancy cohort in Sylhet, Bangladesh, we enrolled 251 consecutive pregnancies resulting in a term livebirth from July 2016-March 2017. Stillbirths, preterm births, and cases of neonatal encephalopathy were excluded. We prospectively collected data on maternal diet (food frequency questionnaire) and morbidity, and analyzed umbilical cord blood for interleukin (IL)-1α, IL-1β, IL-6, IL-8 and C-reactive protein. We determined associations between nutrition and infection exposures and cord cytokine elevation (≥75% vs. <75%) using logistic regression, adjusting for confounders. One-third of mothers were underweight (BMI < 18.5 kg/m2) at enrollment. Antenatal and intrapartum infections were observed among 4.8% and 15.9% of the sample, respectively. Low pregnancy intakes of B vitamins (B1, B2, B3, B6, B9 (folate)), fat-soluble vitamins (D, E), iron, zinc, and linoleic acid (lowest vs. middle tertile) were associated with higher risk of inflammation, particularly IL-8. There was a non-significant trend of increased risk of IL-8 and IL-6 elevation with history of ante-and intrapartum infections, respectively. In Bangladesh, improving micronutrient intake and preventing pregnancy infections are targets to reduce fetal systemic inflammation and associated adverse neurodevelopmental outcomes.

Gut microbiome in people living with HIV is associated with impaired thiamine and folate syntheses

People living with HIV have a high incidence of cardiovascular and neurological diseases as comorbid disorders that are commonly linked to inflammation. While microbial translocation can augment inflammation during HIV infection, functional microbiome shifts that may increase pro-inflammatory responses have not been fully characterized. In addition, defining HIV-induced microbiome changes has been complicated by high variability among individuals. Here we conducted functional annotation of previously-published 16S ribosomal RNA gene sequences of 305 HIV positive and 249 negative individuals, with adjustment for geographic region, sex, sexual behavior, and age. Metagenome profiles were inferred from these individuals' 16S data. HIV infection was associated with impaired microbial vitamin B synthesis; around half of the gene families in thiamine and folate biosynthesis pathways were significantly less abundant in the HIV positive group than the negative control. These results are consistent with the high prevalence of thiamine and folate deficiencies in HIV infections. These HIV-induced microbiota shifts have the potential to influence cardiovascular and neurocognitive diseases, given the documented associations between B-vitamin deficiencies, inflammation, and these diseases. We also observed that most essential amino acid biosynthesis pathways were downregulated in the microbiome of HIV-infected individuals. Microbial vitamin B and amino acid synthesis pathways were not significantly recovered by antiretroviral treatment when we compared 262 ART positive and 184 ART negative individuals. Our meta-analysis provides a new outlook for understanding vitamin B and amino acid deficiencies in HIV patients, suggesting that interventions for reversing HIV-induced microbiome shifts may aid in lessening the burdens of HIV comorbidities.

Effects of Supplementation with Folic Acid and Its Combinations with Other Nutrients on Cognitive Impairment and Alzheimer's Disease: A Narrative Review

Cognitive impairment and Alzheimer's Disease, among other cognitive dysfunctions, has been recognized as a major public health problem. Folic acid is a well-known essential nutrient whose deficiency has been linked to neurocognitive dysfunctions, owing to hyperhomocysteinemia, an independent risk factor for cardio- and cerebrovascular diseases, including cognitive impairment, Alzheimer's Disease, and vascular dementia. However, to date, there is certain controversy about the efficacy of vitamin supplementation in patients with these pathologies. Therefore, we have reviewed the available dietary intervention studies based on folic acid, either alone or in combination with different vitamins or nutrients into the progression of Alzheimer's Disease and Cognitive impairment, highlighting the cognition and biochemical markers employed for the evaluation of the disease progression. Undeniably, the compiled information supports the potential benefits of vitamin supplementation in these pathologies, especially relevant to the aging process and quality of life, although more research is urgently needed to confirm these positive findings.

Good, better, best: clinical scenarios for the use of L-methylfolate in patients with MDD

Depression is among the most prevalent mental disorders worldwide, and a substantial proportion of patients do not respond adequately to standard antidepressants. Our understanding of the pathophysiology of depression is no longer limited to the chemical imbalance of neurotransmitters, but also involves the interplay of proinflammatory modulators in the central nervous system, as well as folate metabolism. Additional factors such as stress and metabolic disorders also may contribute. Multiple inflammatory, metabolic, and genetic markers have been identified and may provide critical information to help clinicians individualize treatments for patients to achieve optimal outcomes. Recent advancements in research have clarified underlying causes of depression and have led to possible new avenues for adjunctive treatment. Among these is L-methylfolate, a medical food that is thought to enhance synthesis of monoamines (serotonin, norepinephrine, and dopamine), suppress inflammation, and promote neural health. Clinical studies that assessed supplemental use of L-methylfolate in patients with usual care-resistant depression found that it resulted in improved outcomes. Patients with selective serotonin reuptake inhibitor-resistant depression, and particularly subgroups with biomarkers of inflammation or metabolic disorders or folate metabolism-related genetic polymorphisms (or ≥2 of these factors), had the best responses. Considering this, the goals of this review are to 1) highlight recent advances in the pathophysiology of major depressive disorder as it pertains to folate and associated biomarkers and 2) establish the profiles of patients with depression who could benefit most from supplemental use of L-methylfolate.

Effects of Folic Acid and Vitamin B12, Alone and in Combination on Cognitive Function and Inflammatory Factors in the Elderly with Mild Cognitive Impairment: A Single-blind Experimental Design

BACKGROUND

Folate and vitamin B12 are well-known as essential nutrients that play key roles in the normal functions of the brain. Inflammatory processes play at least some role in the pathology of AD. Effective nutritional intervention approaches for improving cognitive deficits that reduce the peripheral inflammatory cytokine levels have garnered special attention.

OBJECTIVE

The present study aimed to determine whether supplementation with folic acid and vitamin B12, alone and in combination improves cognitive performance via reducing levels of peripheral inflammatory cytokines.

METHODS

240 participants with MCI were randomly assigned in equal proportion to four treatment groups: folic acid alone, vitamin B12 alone, folic acid plus vitamin B12 or control without treatment daily for 6 months. Cognition was measured with WAIS-RC. The levels of inflammatory cytokines were measured using ELISA. Changes in cognitive function or blood biomarkers were analyzed by repeatedmeasure analysis of variance or mixed-effects models. This trial has been registered with trial number ChiCTR-ROC-16008305.

RESULTS

Compared with control group, the folic acid plus vitamin B12 group had significantly greater improvements in serum folate, homocysteine, vitamin B12 and IL-6, TNF-α, MCP-1. The folic acid plus vitamin B12 supplementation significantly changed the Full Scale IQ (effect size d = 0.169; P = 0.024), verbal IQ (effect size d = 0.146; P = 0.033), Information (d = 0.172; P = 0.019) and Digit Span (d = 0.187; P = 0.009) scores. Post hoc Turkey tests found that folic acid and vitamin B12 supplementation was significantly more effective than folic acid alone for all endpoints.

CONCLUSIONS

The combination of oral folic acid plus vitamin B12 in MCI elderly for six months can significantly improve cognitive performance and reduce the levels of inflammatory cytokines in human peripheral blood. The combination of folic acid and vitamin B12 was significantly superior to either folic acid or vitamin B12 alone.

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.

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.

Invited Commentary: Interaction Between Diet and Chemical Exposures

A growing literature indicates that changes in modifiable factors, including diet, can counteract the toxic developmental and reproductive health effects of chemical exposures. In this issue of the Journal, Gaskins et al. (Am J Epidemiol. 2019;000(000):000-000) present data supporting this hypothesis. Specifically, using data on a cohort of 304 women seeking fertility treatment in Boston, Massachusetts, they found that women with higher exposure to ambient air pollutants had lower fertility treatment success but only when they also consumed <800 μg/day of supplemental folate. No association was observed among women consuming ≥800 μg/day of supplemental folate. The public health importance of this interaction is high: Diet and dietary supplement intake are modifiable factors, whereas exposure to air pollution is less so. While this research question is grounded in a strong biological hypothesis related to epigenetic modifications, oxidative stress, and inflammation, this study raises several key questions. In this commentary, we discuss the inconsistency of the interaction across exposure metrics, the possibility of unmeasured confounding by folate intake, and the importance of examining this association in populations with lower folate intake and/or higher exposure to air pollution.

Folic acid deficiency enhanced microglial immune response via the Notch1/nuclear factor kappa B p65 pathway in hippocampus following rat brain I/R injury and BV2 cells

Recent studies revealed that folic acid deficiency (FD) increased the likelihood of stroke and aggravated brain injury after focal cerebral ischaemia. The microglia-mediated inflammatory response plays a crucial role in the complicated pathologies that lead to ischaemic brain injury. However, whether FD is involved in the activation of microglia and the neuroinflammation after experimental stroke and the underlying mechanism is still unclear. The aim of the present study was to assess whether FD modulates the Notch1/nuclear factor kappa B (NF-κB) pathway and enhances microglial immune response in a rat middle cerebral artery occlusion-reperfusion (MCAO) model and oxygen-glucose deprivation (OGD)-treated BV-2 cells. Our results exhibited that FD worsened neuronal cell death and exaggerated microglia activation in the hippocampal CA1, CA3 and Dentate gyrus (DG) subregions after cerebral ischaemia/reperfusion. The hippocampal CA1 region was more sensitive to ischaemic injury and FD treatment. The protein expressions of proinflammatory cytokines such as tumour necrosis factor-α, interleukin-1β and interleukin-6 were also augmented by FD treatment in microglial cells of the post-ischaemic hippocampus and in vitro OGD-stressed microglia model. Moreover, FD not only dramatically enhanced the protein expression levels of Notch1 and NF-κB p65 but also promoted the phosphorylation of pIkBα and the nuclear translocation of NF-κB p65. Blocking of Notch1 with N-[N-(3, 5-difluorophenacetyl)-l-alanyl]-S-phenylglycine t-butyl ester partly attenuated the nuclear translocation of NF-κB p65 and the protein expression of neuroinflammatory cytokines in FD-treated hypoxic BV-2 microglia. These results suggested that Notch1/NF-κB p65 pathway-mediated microglial immune response may be a molecular mechanism underlying cerebral ischaemia-reperfusion injury worsened by FD treatment.

Homocysteine and age-associated disorders

There are numerous theories of aging, a process which still seems inevitable. Aging leads to cancer and multi-systemic disorders as well as chronic diseases. Decline in age- associated cellular functions leads to neurodegeneration and cognitive decline that affect the quality of life. Accumulation of damage, mutations, metabolic changes, failure in cellular energy production and clearance of altered proteins over the lifetime, and hyperhomocysteinemia, ultimately result in tissue degeneration. The decline in renal functions, nutritional deficiencies, deregulation of methionine cycle and deficiencies of homocysteine remethylation and transsulfuration cofactors cause elevation of homocysteine with advancing age. Abnormal accumulation of homocysteine is a risk factor of cardiovascular, neurodegenerative and chronic kidney disease. Moreover, approximately 50% of people, aged 65 years and older develop hypertension and are at a high risk of developing cardiovascular insufficiency and incurable neurodegenerative disorders. Increasing evidence suggests inverse relation between cognitive impairment, cerebrovascular and cardiovascular events and renal function. Oxidative stress, inactivation of nitric oxide synthase pathway and mitochondria dysfunction associated with impaired homocysteine metabolism lead to aging tissue degeneration. In this review, we examine impact of high homocysteine levels on changes observed with aging that contribute to development and progression of age associated diseases.

Gut microbiota and inflammation in chronic kidney disease and their roles in the development of cardiovascular disease

The health and proper functioning of the cardiovascular and renal systems largely depend on crosstalk in the gut-kidney-heart/vessel triangle. Recent evidence suggests that the gut microbiota has an integral function in this crosstalk. Mounting evidence indicates that the development of chronic kidney and cardiovascular diseases follows chronic inflammatory processes that are affected by the gut microbiota via various immune, metabolic, endocrine, and neurologic pathways. Additionally, deterioration of the function of the cardiovascular and renal systems has been reported to disrupt the original gut microbiota composition, further contributing to the advancement of chronic cardiovascular and renal diseases. Considering the interaction between the gut microbiota and the renal and cardiovascular systems, we can infer that interventions for the gut microbiota through diet and possibly some medications can prevent/stop the vicious cycle between the gut microbiota and the cardiovascular/renal systems, leading to a decrease in chronic cardiovascular and renal diseases.

Neglected tropical diseases and vitamin B12: a review of the current evidence

Vitamin B12 deficiency is an urgent public health problem that disproportionately affects individuals in low- and middle-income settings, where the burden of neglected tropical diseases (NTDs) is also unacceptably high. Emerging evidence supports a potential role of micronutrients in modulating the risk and severity of NTDs. However, the role of vitamin B12 in NTD pathogenesis is unknown. This systematic review was conducted to evaluate the evidence on the role of vitamin B12 in the etiology of NTDs. Ten studies were included in this review: one study using an in vitro/animal model, eight observational human studies and one ancillary analysis conducted within an intervention trial. Most research to date has focused on vitamin B12 status and helminthic infections. One study examined the effects of vitamin B12 interventions in NTDs in animal and in vitro models. Few prospective studies have been conducted to date to examine the role of vitamin B12 in NTDs. The limited literature in this area constrains our ability to make specific recommendations. Larger prospective human studies are needed to elucidate the role of vitamin B12 in NTD risk and severity in order to inform interventions in at-risk populations.

Remote ischemic conditioning as a cytoprotective strategy in vasculopathies during hyperhomocysteinemia: An emerging research perspective

Higher levels of nonprotein amino acid homocysteine (Hcy), that is, hyperhomocysteinemia (HHcy) (~5% of general population) has been associated with severe vasculopathies in different organs; however, precise molecular mechanism(s) as to how HHcy plays havoc with body's vascular networks are largely unknown. Interventional modalities have not proven beneficial to counter multifactorial HHcy's effects on the vascular system. An ancient Indian form of exercise called 'yoga' causes transient ischemia as a result of various body postures however the cellular mechanisms are not clear. We discuss a novel perspective wherein we argue that application of remote ischemic conditioning (RIC) could, in fact, deliver anticipated results to patients who are suffering from chronic vascular dysfunction due to HHcy. RIC is the mechanistic phenomenon whereby brief episodes of ischemia-reperfusion events are applied to distant tissues/organs; that could potentially offer a powerful tool in mitigating chronic lethal ischemia in target organs during HHcy condition via simultaneous reduction of inflammation, oxidative and endoplasmic reticulum stress, extracellular matrix remodeling, fibrosis, and angiogenesis. We opine that during ischemic conditioning our organs cross talk by releasing cellular messengers in the form of exosomes containing messenger RNAs, circular RNAs, anti-pyroptotic factors, protective cytokines like musclin, transcription factors, small molecules, anti-inflammatory, antiapoptotic factors, antioxidants, and vasoactive gases. All these could help mobilize the bone marrow-derived stem cells (having tissue healing properties) to target organs. In that context, we argue that RIC could certainly play a savior's role in an unfortunate ischemic or adverse event in people who have higher levels of the circulating Hcy in their systems.

Intake of Dietary One-Carbon Metabolism-Related B Vitamins and the Risk of Esophageal Cancer: A Dose-Response Meta-Analysis

Several B vitamins are essential in the one-carbon metabolism pathway, which is central to DNA methylation, synthesis, and repair. Moreover, an imbalance in this pathway has been linked to certain types of cancers. Here, we performed a meta-analysis in order to investigate the relationship between the intake of four dietary one-carbon metabolism-related B vitamins (B2, B6, folate, and B12) and the risk of esophageal cancer (EC). We searched PubMed, Web of Science, and Embase for relevant studies published through 1 March 2018. The odds ratio (OR) with 95% confidence interval (CI) for the highest versus the lowest level of each dietary B vitamin was then calculated. From 21 articles reporting 26 studies including 6404 EC cases and 504,550 controls, we found an inverse correlation between the consumption of vitamin B6 and folate and the risk of EC; this association was specific to the US, Europe, and Australia, but was not found in Asia. A dose-response analysis revealed that each 100 μg/day increase in folate intake reduced the risk of EC by 12%. Moreover, each 1 mg/day increase in vitamin B6 intake decreased the risk of EC by 16%. Surprisingly, we found that each 1 μg/day increase in vitamin B12 intake increased the risk of esophageal adenocarcinoma by 2%, particularly in the US and Europe, suggesting both geographic and histological differences. Together, our results suggest that an increased intake of one-carbon metabolism-related B vitamins may protect against EC, with the exception of vitamin B12, which should be consumed in moderation.

Insights on Localized and Systemic Delivery of Redox-Based Therapeutics

Reactive oxygen and nitrogen species are indispensable in cellular physiology and signaling. Overproduction of these reactive species or failure to maintain their levels within the physiological range results in cellular redox dysfunction, often termed cellular oxidative stress. Redox dysfunction in turn is at the molecular basis of disease etiology and progression. Accordingly, antioxidant intervention to restore redox homeostasis has been pursued as a therapeutic strategy for cardiovascular disease, cancer, and neurodegenerative disorders among many others. Despite preliminary success in cellular and animal models, redox-based interventions have virtually been ineffective in clinical trials. We propose the fundamental reason for their failure is a flawed delivery approach. Namely, systemic delivery for a geographically local disease limits the effectiveness of the antioxidant. We take a critical look at the literature and evaluate successful and unsuccessful approaches to translation of redox intervention to the clinical arena, including dose, patient selection, and delivery approach. We argue that when interpreting a failed antioxidant-based clinical trial, it is crucial to take into account these variables and importantly, whether the drug had an effect on the redox status. Finally, we propose that local and targeted delivery hold promise to translate redox-based therapies from the bench to the bedside.

Behavioral alterations are associated with vitamin B12 deficiency in the transcobalamin receptor/CD320 KO mouse

Vitamin B12 (cobalamin) deficiency is prevalent worldwide and causes megaloblastic anemia and neurologic deficits. While the anemia can be treated, the neurologic deficits can become refractive to treatment as the disease progresses. Therefore, timely intervention is critical for a favorable outcome. Moreover, the metabolic basis for the neuro-pathologic changes and the role of cobalamin deficiency in the pathology still remains unexplained. Using a transcobalamin receptor / CD320 knockout mouse that lacks the receptor for cellular uptake of transcobalamin bound cobalamin, we aimed to determine whether cobalamin deficiency in the central nervous system produced functional neurologic deficits in the mouse that would parallel those observed in humans. Our behavioral analyses indicate elevated anxiety and deficits in learning, memory and set-shifting of a spatial memory task in the KO mouse. Consistent with the behavioral deficits, the knockout mouse shows impaired expression of the early phase of hippocampal long-term potentiation along with reduced expression of GluR1, decreased brain mass and a significant reduction in the size of nuclei of the hippocampal pyramidal neurons. Our study suggests that the CD320 knockout mouse develops behavioral deficits associated with cobalamin deficiency and therefore could provide a model to understand the metabolic and genetic basis of neuro-pathologic changes due to cobalamin deficiency.

Addition of vitamin B12 to exercise training improves cycle ergometer endurance in advanced COPD patients: A randomized and controlled study

Vitamin B12 is essential in the homocysteine, mitochondrial, muscle and hematopoietic metabolisms, and its effects on exercise tolerance and kinetics adjustments of oxygen consumption (V'O_2p) in rest-to-exercise transition in COPD patients are unknown. This randomized, double-blind, controlled study aimed to verify a possible interaction between vitamin B12 supplementation and these outcomes. After recruiting 69 patients, 35 subjects with moderate-to-severe COPD were eligible and 32 patients concluded the study, divided into four groups (n = 8 for each group): 1. rehabilitation group; 2. rehabilitation plus B12 group; 3. B12 group; and 4. placebo group. The primary endpoint was cycle ergometry endurance before and after 8 weeks and the secondary endpoints were oxygen uptake kinetics parameters (time constant). The prevalence of vitamin B12 deficiency was high (34.4%) and there was a statistically significant interaction (p < 0.05), favoring a global effect of supplementation on exercise tolerance in the supplemented groups compared to the non-supplemented groups, even after adjusting for confounding variables (p < 0.05). The same was not found for the kinetics adjustment variables (τV'O_2p and _MRTV'O_2p, p > 0.05 for both). Supplementation with vitamin B12 appears to lead to discrete positive effects on exercise tolerance in groups of subjects with more advanced COPD and further studies are needed to establish indications for long-term supplementation.

The relationship between hyperhomocysteinemia and neurodegeneration

Homocysteine (Hcy) is a key junction in methionine metabolism. In inherited forms of hyperhomocysteinemia patients develop early vascular damage and cognitive decline. Hyperhomocysteinemia is a common consequence of dietary, behavioral and pathological conditions and is epidemiologically related to different diseases, among them neurodegenerative ones are receiving progressively more attention in the last years. Several detrimental mechanisms that see in Hcy a possible promoter seem to be implicated in neurodegeneration (protein structural and functional modifications, oxidative stress, cellular metabolic derangements, epigenetic modifications, pathological aggregates deposition, endothelial damage and atherothrombosis). Interventional studies exploring B group vitamins administration in terms of prevention of Hcy-related cognitive decline and cerebrovascular involvement have shown scant results. In this review, current and possible alternative/complementary approaches are discussed.