Ascorbic Acid to Manage Psychiatric Disorders

Carbon-doped bimetallic oxide nanoflakes for simultaneous electrochemical analysis of ascorbic acid, uric acid, and acetaminophen in sweat

Non-invasive continuous detection using tears or sweat as substitutes for blood samples has become an emerging method for real-time monitoring of human health. However, its development is limited by the low sample volume and low level of analytes. The simultaneous determination of multi-analytes with highly sensitive electrochemical sensing platforms has undoubtedly resulted in breakthrough innovations. Furthermore, the determination mode of multi-analyte combinations can accurately characterize the course of certain diseases. In particular, the simultaneous determination of ascorbic acid (AA), uric acid (UA), and acetaminophen (AC) in sweat will provide a one-stop detection system for cardiovascular and degenerative diseases for the entire course analysis. A sacrificial template strategy was adopted in this work using graphene oxide (GO) to guide the growth of two-dimensional Fe-Co composite nanoflakes with large specific surface areas. Defects were introduced via doping carbon through the incomplete pyrolysis of GO. The synthesized C-Fe1.33Co1.67O4 exhibited massive redox sites and was highly reactive, which met the requirements for multi-substance analysis. The electrochemical sensor based on C-Fe1.33Co1.67O4 accurately and sensitively demonstrated simultaneous detection of AA, UA, and AC in sweat, with a wide detection range for AA (4.0-11500 μM) and high sensitivity for UA and AC (304.5 μA mM-1 and 404.1 μA mM-1, respectively), along with low detection limit (1.69 μM for AA, 0.23 μM for UA, and 0.07 μM for AC). The sensor also possessed adequate mechanical flexibility, making it suitable for body surface detection, and its performance was maintained above 80% after high-intensity bending 350 times.

Highly stable Tb(III) metal-organic framework derived from a new benzothiadiazole functionalized ligand for fluorescence recognition of ascorbic acid

Because ascorbic acid (AA) is one of the basic elements to maintain the normal physiological functions of human body, it is urgent to develop a material that can achieve efficient, rapid and in-situ detection for AA. A new fluorescence organic compound 4',4'''-(benzo[c][1,2,5]thiadiazole-4,7-diyl)bis([1,1'-biphenyl]-4-carboxylic acid) (H2BTBC) based on benzothiadiazole group has been synthesized, which can detect Fe3+ ions by fluorescence turn-off effect with a detection limit of 0.015 μM, as well as recognize linear amines by fluorescence turn-on effect. Moreover, a highly stable Tb(III) metal-organic framework has been solvothermally prepared with H2BTBC, namely {[(CH3)2NH2]2[Tb2(BTBC)4]∙solvents}n (JXUST-39), which can selectively detect AA among biological fluids by fluorescence enhancement effect with a detection limit of 0.077 μM. In addition, the mechanism for JXUST-39 detecting AA is possibly the cooperative effect of absorbance-caused enhancement and charge transfer between JXUST-39 and AA. Moreover, LED lamp beads, fluorescent films and fluorescent detection test paper based on JXUST-39 were prepared to achieve portable detection via fluorescence enhancement effect.

A dual-signal optical sensing platform of CDs-MnO2 NS composites for facile detection of ascorbic acid based on a combination of Tyndall effect scattering and fluorescence

A dual-signal optical sensing platform was successfully developed for the determination of ascorbic acid (AA) based on blue fluorescent carbon dots (CDs) and manganese dioxide nanosheets (MnO2 NSs) with strong Tyndall effect (TE) scattering and fluorescence quenching capabilities. In this nanosystem, CDs-MnO2 NS composites were employed as probes to evaluate the AA concentration. Owing to the strong reduction, the presence of the target AA could reduce the MnO2 NSs to Mn2+ and induce the degradation of the MnO2 NSs, resulting in a significant decrease in the TE scattering intensity of the MnO2 NSs and the fluorescence recovery of the CDs. Therefore, a novel optical sensor based on TE scattering and fluorescence dual detectors was developed for the sensitive determination of AA. Under optimized conditions, the limits of detection (LODs) of the two modes were 113 and 3 nM, respectively. Furthermore, the dual-signal optical sensing platform was successfully applied for the detection of AA in human serum.

Neuroprotection Role of Vitamin C by Upregulating Glutamate Transporter-1 in Auditory Cortex of Noise-Induced Tinnitus Animal Model

Vitamin C (Vc) plays a pivotal role in a series of pathological processes, such as tumors, immune diseases, and neurological disorders. However, its therapeutic potential for tinnitus management remains unclear. In this study, we find that Vc relieves tinnitus in noise-exposed rats. In the 7-day therapy groups, spontaneous firing rate (SFR) increases from 1.17 ± 0.10 Hz to 1.77 ± 0.15 Hz after noise exposure. Vc effectively reduces the elevated SFR to 0.99 ± 0.07 and 0.55 ± 0.05 Hz at different doses. The glutamate level in auditory cortex of noise-exposed rats (3.78 ± 0.42 μM) increases relative to that in the control group (1.34 ± 0.22 μM). High doses of Vc (500 mg/kg/day) effectively reduce the elevated glutamate levels (1.49 ± 0.28 μM). Mechanistic studies show that the expression of glutamate transporter 1 (GLT-1) is impaired following noise exposure and that Vc treatment effectively restores GLT-1 expression in the auditory cortex. Meanwhile, the GLT-1 inhibitor, dl-threo-beta-benzyloxyaspartic acid (dl-TBOA), invalidates the protection role of Vc. Our finding shows that Vc substantially enhances glutamate clearance by upregulating GLT-1 and consequently alleviates noise-induced tinnitus. This study provides valuable insight into a novel biological target for the development of therapeutic interventions that may prevent the onset of tinnitus.

PEI-based functional materials: Fabrication techniques, properties, and biomedical applications

Cationic polymers have recently attracted considerable interest as research breakthroughs for various industrial and biomedical applications. They are particularly interesting due to their highly positive charges, acceptable physicochemical properties, and ability to undergo further modifications, making them attractive candidates for biomedical applications. Polyethyleneimines (PEIs), as the most extensively utilized polymers, are one of the valuable and prominent classes of polycations. Owing to their flexible polymeric chains, broad molecular weight (MW) distribution, and repetitive structural units, their customization for functional composites is more feasible. The specific beneficial attributes of PEIs could be introduced by purposeful functionalization or modification, long service life, biocompatibility, and distinct geometry. Therefore, PEIs have significant potential in biotechnology, medicine, and bioscience. In this review, we present the advances in PEI-based nanomaterials, their transfection efficiency, and their toxicity over the past few years. Furthermore, the potential and suitability of PEIs for various applications are highlighted and discussed in detail. This review aims to inspire readers to investigate innovative approaches for the design and development of next-generation PEI-based nanomaterials possessing cutting-edge functionalities and appealing characteristics.

Role of Inflammatory Mechanisms in Major Depressive Disorder: From Etiology to Potential Pharmacological Targets

The involvement of central and peripheral inflammation in the pathogenesis and prognosis of major depressive disorder (MDD) has been demonstrated. The increase of pro-inflammatory cytokines (interleukin (IL)-1β, IL-6, IL-18, and TNF-α) in individuals with depression may elicit neuroinflammatory processes and peripheral inflammation, mechanisms that, in turn, can contribute to gut microbiota dysbiosis. Together, neuroinflammation and gut dysbiosis induce alterations in tryptophan metabolism, culminating in decreased serotonin synthesis, impairments in neuroplasticity-related mechanisms, and glutamate-mediated excitotoxicity. This review aims to highlight the inflammatory mechanisms (neuroinflammation, peripheral inflammation, and gut dysbiosis) involved in the pathophysiology of MDD and to explore novel anti-inflammatory therapeutic approaches for this psychiatric disturbance. Several lines of evidence have indicated that in addition to antidepressants, physical exercise, probiotics, and nutraceuticals (agmatine, ascorbic acid, and vitamin D) possess anti-inflammatory effects that may contribute to their antidepressant properties. Further studies are necessary to explore the therapeutic benefits of these alternative therapies for MDD.

Silva H, P. de Carvalho R, Ventura ALM, Calaza KC, Silveira MS, Kubrusly RCC, de Melo Reis RA. The Healthy and Diseased Retina Seen through Neuron-Glia Interactions

The retina is the sensory tissue responsible for the first stages of visual processing, with a conserved anatomy and functional architecture among vertebrates. To date, retinal eye diseases, such as diabetic retinopathy, age-related macular degeneration, retinitis pigmentosa, glaucoma, and others, affect nearly 170 million people worldwide, resulting in vision loss and blindness. To tackle retinal disorders, the developing retina has been explored as a versatile model to study intercellular signaling, as it presents a broad neurochemical repertoire that has been approached in the last decades in terms of signaling and diseases. Retina, dissociated and arranged as typical cultures, as mixed or neuron- and glia-enriched, and/or organized as neurospheres and/or as organoids, are valuable to understand both neuronal and glial compartments, which have contributed to revealing roles and mechanisms between transmitter systems as well as antioxidants, trophic factors, and extracellular matrix proteins. Overall, contributions in understanding neurogenesis, tissue development, differentiation, connectivity, plasticity, and cell death are widely described. A complete access to the genome of several vertebrates, as well as the recent transcriptome at the single cell level at different stages of development, also anticipates future advances in providing cues to target blinding diseases or retinal dysfunctions.

A metabolic biomarker panel of restless legs syndrome in peritoneal dialysis patients

BACKGROUND

Restless legs syndrome (RLS) is a neuromotor disorder, and dialysis patients are more likely to develop RLS. RLS often causes sleep disorders, anxiety and depression in patients. It will increase the risk of death and severely affect the life of patients. At present, RLS has not received enough recognition and attention, and the misdiagnosis rate can reach more than 10%.

METHODS

The discovery set selected 30 peritoneal dialysis (PD) patients and 27 peritoneal dialysis patients with RLS (PD-RLS). A metabolomics method based on ultra performance liquid chromatography tandem quadrupole time-of-flight mass spectrometric method (UPLC-Q-TOF/MS) was used to analyze the differential metabolites of the two groups. 51 PD patients and 51 PD-RLS patients were included in the validation set. The receiver operating characteristic (ROC) analysis was used to evaluate the early diagnostic biomarkers, and the correlation between the differential metabolites and laboratory test indexes was analyzed to explore the biological function of the differential metabolites.

RESULTS

Through the integrated analysis, four metabolites can be used as markers for the diagnosis of PD-RLS, including Hippuric acid, Phenylacetylglutamine, N,N,N-Trimethyl-L-alanyl-L-proline betaine and Threonic acid. Through ROC analysis, it is found that they can be used as a metabolic biomarker panel, and the area under the curve of this combination is more than 0.9, indicating that the panel has good diagnostic and predictive ability.

CONCLUSION

Metabolomics based on UPLC-Q-TOF/MS technology can effectively identify the potential biomarkers, and provide a theoretical basis for the early diagnosis, prevention and treatment on PD-RLS.

Relationship between Vitamin C Deficiency and Cognitive Impairment in Older Hospitalised Patients: A Cross-Sectional Study

Vitamin C is a powerful antioxidant and facilitates neurotransmission. This study explored association between vitamin C deficiency and cognitive impairment in older hospitalised patients. This prospective study recruited 160 patients ≥ 75 years admitted under a Geriatric Unit in Australia. Cognitive assessment was performed by use of the Mini-Mental-State-Examination (MMSE) and patients with MMSE scores <24 were classified as cognitively-impaired. Fasting plasma vitamin C levels were determined using high-performance-liquid-chromatography. Patients were classified as vitamin C deficient if their levels were below 11 micromol/L. Logistic regression analysis was used to determine whether vitamin C deficiency was associated with cognitive impairment after adjustment for various covariates. The mean (SD) age was 84.4 (6.4) years and 60% were females. A total of 91 (56.9%) were found to have cognitive impairment, while 42 (26.3%) were found to be vitamin C deficient. The mean (SD) MMSE scores were significantly lower among patients who were vitamin C deficient (24.9 (3.3) vs. 23.6 (3.4), p-value = 0.03). Logistic regression analysis suggested that vitamin C deficiency was 2.9-fold more likely to be associated with cognitive impairment after adjustment for covariates (aOR 2.93, 95% CI 1.05−8.19, p-value = 0.031). Vitamin C deficiency is common and is associated with cognitive impairment in older hospitalised patients.

Dietary Vitamin C and Vitamin C Derived from Vegetables Are Inversely Associated with the Risk of Depressive Symptoms among the General Population

Vitamin C is a water-soluble antioxidant. Reducing the level of oxidative stress can alleviate depression. Therefore, we investigated the correlation between dietary vitamin C intake and the risk of depressive symptoms in the general population. Data from the 2007–2018 National Health and Nutrition Examination Survey were used in our study. The dietary intake of vitamin C was assessed by two 24-h dietary recalls. Depressive symptoms were assessed with the Patient Health Questionnaire-9. Logistic regression and restricted cubic spline models were applied to assess the relationship between dietary vitamin C intake and the risk of depressive symptoms. The multivariate adjusted odds ratio (95% confidence interval) of depressive symptoms for the highest vs. lowest category of dietary vitamin C intake and vitamin C intake derived from vegetables were 0.73 (0.58–0.91) and 0.73 (0.56–0.95). In subgroup analyses, dietary vitamin C intake was negatively correlated with the risk of depressive symptoms in females 18–39 years old and 40–59 year-old groups. A dose-response analysis showed that there was a nonlinear relationship between dietary vitamin C intake and the risk of depressive symptoms. Dietary vitamin C intake and vitamin C intake derived from vegetables were inversely associated with the risk of depressive symptoms among the general population. We recommend increasing the intake of vegetables in daily diet.

Antidepressant Like Effect of Ascorbic Acid in Mice: Possible Involvement of NO-sGC-cGMP Signaling

The present study was designed to determine the antidepressant like activity of ascorbic acid (AA) in mice. Further the influence of NO-sGC-cGMP signaling in the antidepressant like effect of AA in mice was determined. Male swiss albino mice were used in the present study. Mice in the control group received saline and fluoxetine (10 mg/kg, i.p.) was used as the standard antidepressant drug. AA (50, 100 and 150 mg/kg, i.p.) was administered to the mice and depression related behavior were determined using tail suspension test (TST) and forced swim test (FST). Further the whole brain nitrite and serotonin levels were also determined. It was observed that the administration of AA (100 mg/kg, i.p.) reversed the depression like behavior in mice in TST and FST. AA (100 mg/kg, i.p.) treatment decreased the level of nitrite and increased the level of serotonin in the brain of mice significantly as compared to control. Further the behavioral and neurochemical effect of AA (50 mg/kg, i.p) was studied in NO modulator [NO donor: L-Arginine (50 mg/kg, i.p); NO-sGC inhibitor: methylene blue (1 mg/kg, i.p.) and cGMP modulator: sildenafil (1 mg/kg, i.p.)] pretreated mice. It was observed that the pretreatment of NO donor and cGMP modulator counteracted the effect conferred by AA (50 mg/kg, i.p). While the pretreatment of NO-sGC inhibitor potentiated the effect conferred by AA (50 mg/kg, i.p). The present study suggested that the AA confer antidepressant like effect in mice and NO-sGC-cGMP signaling pathway influence the antidepressant like effect of AA in mice.

Effect of Adjuvant Vitamin C on Brain-Derived Neurotrophic Factor Levels and Improvement of Negative Symptoms in Schizophrenic Patients

AIM: This study aims to determine the effect of adjuvant Vitamin C on brain-derived neurotropic factors (BDNF) levels and improvement of negative symptoms in schizophrenic patients. METHODS: This study was conducted at Hasanuddin University Hospital and its affiliate with 60 schizophrenic patients (30 controls, 27 treatments, and three dropout patients). The ELISA sample examination method was used to examine blood levels of BDNF, and Vitamin C levels before and after administration of Vitamin C. In addition, the negative symptoms were measured using the PANSS score. RESULTS: There was a significant increase in BDNF levels in treatments group compared the control at 4th–8th weeks with p = 0.005 (4th week) and ≤0.0001 (<0.05) (8th week). The improvement in PANSS scores for negative symptoms in the treatment groups compared to the controls at the 2nd, 4th, and 8th weeks resulted in p = 0.042 (2nd week) and <0.0001 (4th–8th weeks). Furthermore, there was an increase in serum Vitamin C levels in the treatment groups with an initial average value = 4.762 and after 8 weeks = 148.155. Strong correlation between increased BDNF levels and improvement in negative symptoms on the PANSS score was found with p = 0.001 (4th week) and ≤0.0001 (8th week). CONCLUSION: The administration of Vitamin C significantly increases BDNF levels and improves the PANSS score for negative symptoms in the treatments compared to the control groups.

Functional role of ascorbic acid in the central nervous system: a focus on neurogenic and synaptogenic processes

Ascorbic acid, a water-soluble vitamin, is highly concentrated in the brain and participates in neuronal modulation and regulation of central nervous system (CNS) homeostasis. Ascorbic acid has emerged as a neuroprotective compound against neurotoxicants and neurodegenerative diseases, including Alzheimer's disease, multiple sclerosis and amyotrophic lateral sclerosis. Moreover, it improves behavioral and biochemical alterations in psychiatric disorders, including schizophrenia, anxiety, major depressive disorder, and bipolar disorder. Some recent studies have advanced the knowledge on the mechanisms associated with the preventive and therapeutic effects of ascorbic acid by showing that they are linked to improved neurogenesis and synaptic plasticity. This review shows that ascorbic acid has the potential to regulate positively stem cell generation and proliferation. Moreover, it improves neuronal differentiation of precursors cells, promotes adult hippocampal neurogenesis, and has synaptogenic effects that are possibly linked to its protective or therapeutic effects in the brain.

Quercetin and/or Ascorbic Acid Modulatory Effect on Phenobarbital-Induced Sleeping Mice Possibly through GABAA and GABAB Receptor Interaction Pathway

Depressive disorder is a recurrent illness that affects large numbers of the general population worldwide. In recent years, the goal of depression treatment has moved from symptomatic response to that of full remission. However, treatment-resistant depression is a major challenge in the treatment of depression or depression-related disorders. Consensus opinion, therefore, suggests that effective combined aggressive initial treatment is the most appropriate strategy. This study aimed to evaluate the effects of quercetin (QUR) and/or ascorbic acid (AA) on Phenobarbital-induced sleeping mice. QUR (50 mg/kg) and/or AA (25 mg/kg) with or without intraperitoneally pre-treated with GABA receptor agonist (diazepam: 2 mg/kg, i.p.) or antagonist (Flumazenil: 2.5 mg/kg, i.p.) to underscore the effects, as well as the possible involvement of the GABA receptor in the modulatory action of QUR and AA in sleeping mice. Additionally, an in silico study was undertaken to predict the involvement of GABA receptors in the sleep mechanism. Findings suggest that the pretreatment of QUR and AA modulated the onset and duration of action of the standard drugs in experimental animals. The acute administration of QUR and/or AA significantly (p < 0.05) reversed the DZP-mediated onset of action and slightly reversed the duration of sleep time in comparison to the vehicle (control) group. A further combination of QUR or AA with the FLU resulted in an enhancement of the onset of action while reducing the duration of action, suggesting a FLU-like effect on the test animals. In in silico studies, AA and QUR showed good to moderate binding affinities with GABA_A and GABA_B receptors. Both QUR and AA produced a stimulatory-like effect on mice, possibly through the GABA_A and GABA_B receptor interaction pathways. Further studies are necessary to verify this activity and clarify the exact mechanism of action(s) involved.

Vitamin C Deficiency in the Young Brain-Findings from Experimental Animal Models

Severe and long-term vitamin C deficiency can lead to fatal scurvy, which is fortunately considered rare today. However, a moderate state of vitamin C (vitC) deficiency (hypovitaminosis C)-defined as a plasma concentration below 23 μM-is estimated to affect up to 10% of the population in the Western world, albeit clinical hallmarks in addition to scurvy have not been linked to vitC deficiency. The brain maintains a high vitC content and uniquely high levels during deficiency, supporting vitC's importance in the brain. Actions include both antioxidant and co-factor functions, rendering vitamin C deficiency likely to affect several targets in the brain, and it could be particularly significant during development where a high cellular metabolism and an immature antioxidant system might increase sensitivity. However, investigations of a non-scorbutic state of vitC deficiency and effects on the developing young brain are scarce. This narrative review provides a comprehensive overview of the complex mechanisms that regulate vitC homeostasis in vivo and in the brain in particular. Functions of vitC in the brain and the potential consequences of deficiency during brain development are highlighted, based primarily on findings from experimental animal models. Perspectives for future investigations of vitC are outlined.

A single administration of ascorbic acid rapidly reverses depressive-like behavior and hippocampal synaptic dysfunction induced by corticosterone in mice

Ketamine is the prototype for glutamate-based fast-acting antidepressants. The establishment of ketamine-like drugs is still a challenge and ascorbic acid has emerged as a candidate. This study investigated the ascorbic acid's ability to induce a fast antidepressant-like response and to improve hippocampal synaptic markers in mice subjected to chronic corticosterone (CORT) administration. CORT was administered for 21 days, followed by a single administration of ascorbic acid (1 mg ∕Kg, p.o.), ketamine (1 mg ∕Kg, i.p.) or fluoxetine (10 mg ∕Kg, p.o.) in mice. Depressive-like behavior, hippocampal synaptic proteins immunocontent, dendrite spines density in the dentate gyrus (DG) were analyzed 24 h following treatments. The administration of ascorbic acid or ketamine, but not fluoxetine, counteracted CORT-induced depressive-like behavior in the tail suspension test (TST). CORT administration reduced PSD-95, GluA1, and synapsin (synaptic markers) immunocontent, and these alterations were reversed by ascorbic acid or ketamine, but only ketamine reversed the CORT-induced reduction on GluA1 immunocontent. In the ventral and dorsal DG, CORT decreased filopodia-, thin- and stubby-shaped spines, while ascorbic acid and ketamine abolished this alteration only in filopodia spines. Ascorbic acid and ketamine increased mushroom-shaped spines density in ventral and dorsal DG. Therefore, the results show that a single administration of ascorbic acid, in a way similar to ketamine, rapidly elicits an antidepressant-like response and reverses hippocampal synaptic deficits caused by CORT, an effect associated with increased levels of synaptic proteins and dendritic remodeling.

Circulating Extracellular Vesicles: The Missing Link between Physical Exercise and Depression Management?

Depression is associated with an increased risk of aging-related diseases. It is also seemingly a common psychological reaction to pandemic outbreaks with forced quarantines and lockdowns. Thus, depression represents, now more than ever, a major global health burden with therapeutic management challenges. Clinical data highlights that physical exercise is gaining momentum as a non-pharmacological intervention in depressive disorders. Although it may contribute to the reduction of systemic inflammation associated with depression, the mechanisms underlying the beneficial physical exercise effects in emotional behavior remain to be elucidated. Current investigations indicate that a rapid release of extracellular vesicles into the circulation might be the signaling mediators of systemic adaptations to physical exercise. These biological entities are now well-established intercellular communicators, playing a major role in relevant physiological and pathophysiological functions, including brain cell-cell communication. We also reviewed emerging evidence correlating depression with modified circulating extracellular vesicle surfaces and cargo signatures (e.g., microRNAs and proteins), envisioned as potential biomarkers for diagnosis, efficient disease stratification and appropriate therapeutic management. Accordingly, the clinical data summarized in the present review prompted us to hypothesize that physical exercise-related circulating extracellular vesicles contribute to its antidepressant effects, particularly through the modulation of inflammation. This review sheds light on the triad "physical exercise-extracellular vesicles-depression" and suggests new avenues in this novel emerging field.

Seizure-Induced Oxidative Stress in Status Epilepticus: Is Antioxidant Beneficial?

Epilepsy is a common neurological disorder which affects patients physically and mentally and causes a real burden for the patient, family and society both medically and economically. Currently, more than one-third of epilepsy patients are still under unsatisfied control, even with new anticonvulsants. Other measures may be added to those with drug-resistant epilepsy. Excessive neuronal synchronization is the hallmark of epileptic activity and prolonged epileptic discharges such as in status epilepticus can lead to various cellular events and result in neuronal damage or death. Unbalanced oxidative status is one of the early cellular events and a critical factor to determine the fate of neurons in epilepsy. To counteract excessive oxidative damage through exogenous antioxidant supplements or induction of endogenous antioxidative capability may be a reasonable approach for current anticonvulsant therapy. In this article, we will introduce the critical roles of oxidative stress and further discuss the potential use of antioxidants in this devastating disease.

Antioxidant vitamin intakes and risk of depression, anxiety and stress among female adolescents

BACKGROUND AND AIM

The relation of some antioxidant nutrients with psychological disorders has been studied previously. The aim of this study was to examine the association between antioxidant vitamin intakes and the risk of depression, anxiety, and stress.

METHODS

This cross-sectional study was conducted on 263 Tehranian female adolescents. Dietary intakes of vitamin E, C, and β-Carotene were determined using a valid and reliable food-frequency questionnaire. Depression, anxiety, and stress scores were characterized by DASS-21 (Depression Anxiety Stress Score-21 items) questionnaire. The multivariable logistic regression models were used to determine the odds ratios (ORs) and 95% confidence intervals (95%CIs) of depression, anxiety, and stress across tertiles of antioxidant vitamin intakes.

RESULTS

The mean ± SD age of participants was 16.20 ± 0.97 years. Also, the mean ± SD depression, anxiety and stress scores of participants were 9.89 ± 4.15, 8.43 ± 4.39 and 14.00 ± 6.45, respectively. In the fully adjusted model, subjects in the highest tertile of β-Carotene had a lower prevalence of depression (OR:0.46, 95%CI:0.23-0.95), anxiety (OR:0.40, 95%CI:0.20-0.81), and stress (OR:0.35, 95%CI:0.17-0.73) compared to the lowest tertile (P for trend<0.05). Moreover, individuals in the top tertile of vitamin E had a lower prevalence of stress, in comparison to the bottom tertile (OR:0.34, 95% CI:0.13-0.89), (P for trend<0.05). However, no significant associations were found between the intakes of vitamin E and C and other psychological disorders.

CONCLUSION

In this study, higher intake of β-Carotene was associated with lower prevalence of depression, anxiety and stress. Also, we found an inverse relationship between vitamin E intake and the risk of stress.

Dehydroascorbic Acid Affects the Stability of Catechins by Forming Conjunctions

Although tea catechins in green tea and green tea beverages must be stable to deliver good sensory quality and healthy benefits, they are always unstable during processing and storage. Ascorbic acid (AA) is often used to protect catechins in green tea beverages, and AA is easily oxidized to form dehydroascorbic acid (DHAA). However, the function of DHAA on the stability of catechins is not clear. The objective of this study was to determine the effects of DHAA on the stability of catechins and clarify the mechanism of effects by conducting a series of experiments that incubate DHAA with epigallocatechin gallate (EGCG) or catechins. Results showed that DHAA had a dual function on EGCG stability, protecting its stability by inhibiting hydrolysis and promoting EGCG consumption by forming ascorbyl adducts. DHAA also reacted with (−)-epicatechin (EC), (−)-epicatechin gallate (ECG), and (−)-epigallocatechin (EGC) to form ascorbyl adducts, which destabilized them. After 9 h of reaction with DHAA, the depletion rates of EGCG, ECG, EC, and EGC were 30.08%, 22.78%, 21.45%, and 13.55%, respectively. The ability of DHAA to promote catechins depletion went from high to low: EGCG, ECG, EGC, and EC. The results are important for the processing and storage of tea and tea beverages, as well as the general exploration of synergistic functions of AA and catechins.

Ascorbic acid supplementation attenuates schizophrenia-like symptoms in an animal model induced by ketamine

Schizophrenia is a chronic neuropsychiatric disorder with a poorly understood pathophysiology. The theories about the disorder are mainly about dysregulation in one or more systems of neurotransmitters, and the progression triggers the presence of inflammatory markers indicates the possibility that the disorder is initially an inflammatory disease. The objective was to evaluate the ascorbic acid supplementation in an animal model of schizophrenia, on behavioral parameters, and cytokines involved in inflammation IL-1β, IL-10. Wistar rats with 60 days of age were used which were supplemented with ascorbic acid at 0.1, 1, and 10 mg/kg or saline for 14 days via orogastric gavage. Subsequently, four groups were given ketamine (25 mg/kg) and four groups received intraperitoneal saline from the 9th-15th day of the experiment. After 30 min of the last administration of ketamine/saline, and behavioral test, rats were killed by guillotine decapitation and the brain structures were carefully dissected for biochemical analysis. Results showed that ascorbic acid supplementation prevented motor sensory loss but nor alter other parameters evaluated. We concluded that ascorbic acid may be used as a therapeutic adjuvant in schizophrenia and may help to improve the schizophrenic patient's life quality.

Dual effects of ascorbic acid on the stability of EGCG by the oxidation product dehydroascorbic acid promoting the oxidation and inhibiting the hydrolysis pathway

A series of incubation systems of pure (-)-Epigallocatechin gallate (EGCG), ascorbic acid (AA) and dehydroascorbic acid (DHAA) at 80 °C were performed to investigated the effect and mechanism of AA on the stability of EGCG. Results shows the dual function of AA, protect action at low concentration and promoting degradation at high concentration, and the critical concentration is about 10 mmol/L. The protective properties of AA due to the reversible reaction from AA to DHAA inhibiting oxidation pathway of EGCG to EGCG quinone or other activated intermediates, and both AA and DHAA can inhibit the hydrolysis of EGCG. The properties of promoting degradation is mainly due to the fact that DHAA, the oxidation product of AA, can react with EGCG to generate some ascorbyl adducts of EGCG. This result is helpful to control the stability of catechins and further clarify the complex interaction on healthy between EGCG and AA.

Multiple cellular targets involved in the antidepressant-like effect of glutathione

A previous study demonstrated that glutathione (GSH) produces specific antidepressant-like effect in the forced swimming test (FST), a predictive test of antidepressant activity. The present study investigated the involvement of multiple cellular targets implicated in the antidepressant-like effect of GSH in the FST. The antidepressant-like effect of GSH (300 nmol/site, icv) lasted up to 3 h when mice were submitted to FST. The central administration of oxidized GSH (GSSG, 3-300 nmol/site) did not alter the behavior of mice submitted to the FST. Furthermore, the combined treatment of sub-effective doses of GSH (100 nmol/site, icv) with a sub-effective dose of classical antidepressants (fluoxetine 10 mg/kg, and imipramine 5 mg/kg, ip) presented synergistic effect by decreasing the immobility time in the FST. The antidepressant-like effect of GSH was abolished by prazosin (1 mg/kg, ip, α₁-adrenoceptor antagonist), baclofen (1 mg/kg, ip, GABAB receptor agonist), bicuculline (1 mg/kg, ip, GABAA receptor antagonist), l-arginine (750 mg/kg, ip, NO precursor), SNAP (25 μg/site, icv, NO donor), but not by yohimbine (1 mg/kg, ip, α₂-adrenoceptor antagonist). The NMDA receptor antagonists, MK-801(0.001 mg/kg, ip) or GMP (0.5 mg/kg, ip), potentiated the effect of a sub-effective dose of GSH in the FST. These results suggest that the antidepressant-like effect induced by GSH is connected to the activation of α1 adrenergic and GABAA receptors, as well as the inhibition of GABAB and NMDA receptors and NO biosyntesis. We speculate that redox-mediated signaling on the extracelular portion of cell membrane receptors would be a common mechanism of action of GSH.

The role of vitamin C in stress-related disorders

Stress-related disorders, such as depression and anxiety, present marked deficits in behavioral and cognitive functions related to reward. These are highly prevalent disabling conditions with high social and economic costs. Furthermore, a significant percentage of affected individuals cannot benefit from clinical intervention, opening space for new treatments. Although the literature data have reported limited and variable results regarding oxidative stress-related endpoints in stress-related disorders, the possible neuroprotective effect of antioxidant compounds, such as ascorbic acid (vitamin C), emerges as a possible therapy strategy for psychiatric diseases. Here, we briefly present background information on biological activity of ascorbic acid, particularly functions related to the CNS homeostasis. Additionaly, we reviewed the available information on the role of ascorbic acid in stress-related diseases, focusing on supplementation and depletion studies. The vitamin C deficiency is widely associated to stress-related diseases. Although the efficacy of this vitamin in anxiety spectrum disorders is less stablished, several studies showed that ascorbic acid supplementation produces antidepressant effect and improves mood. Interestingly, the modulation of monoaminergic and glutamatergic neurotransmitter systems is postulated as pivotal target for the antidepressant and anxiolytic effects of this vitamin. Given that ascorbic acid supplementation produces fast therapeutic response with low toxicity and high tolerance, it can be considered as a putative candidate for the treatment of mood and anxiety disorders, especially those that are refractory to current treatments. Herein, the literature was reviewed considering the potential use of ascorbic acid as an adjuvant in the treatment of anxiety and depression.

The neuropsychiatric effects of vitamin C deficiency: a systematic review

BACKGROUND

Vitamin C deficiency may be more common than is generally assumed, and the association between vitamin C deficiency and adverse psychiatric effects has been known for centuries. This paper aims to systematically review the evidence base for the neuropsychiatric effects of vitamin C deficiency.

METHODS

Relevant studies were identified via systematic literature review.

RESULTS

Nine studies of vitamin C deficiency, including subjects both with and without the associated physical manifestations of scurvy, were included in this review. Vitamin C deficiency, including scurvy, has been linked to depression and cognitive impairment. No effect on affective or non-affective psychosis was identified.

CONCLUSIONS

Disparate measurement techniques for vitamin C, and differing definitions of vitamin C deficiency were apparent, complicating comparisons between studies. However, there is evidence suggesting that vitamin C deficiency is related to adverse mood and cognitive effects. The vitamin C blood levels associated with depression and cognitive impairment are higher than those implicated in clinical manifestations of scurvy. While laboratory testing for ascorbic acid can be practically difficult, these findings nonetheless suggest that mental health clinicians should be alerted to the possibility of vitamin C deficiency in patients with depression or cognitive impairment. Vitamin C replacement is inexpensive and easy to deliver, although as of yet there are no outcome studies investigating the neuropsychiatric impact of vitamin C replacement in those who are deficient.

On the physiological and cellular homeostasis of ascorbate

Recent interest in the role of ascorbate in crucial metabolic processes is driven by the growing number of medical reports that show beneficial effects of ascorbate supplementation for maintaining general well-being and recovery from a variety of medical conditions. The effect of ascorbate on the local body environment highly depends on its local concentration; at low concentrations it can cause the reduction of reactive oxygen and facilitate activities of enzymes, while at high concentrations it generates free radicals by reducing ferric ions. Ascorbate serving as an electron donor assists the iron-containing proteins and the iron transfer between various aqueous compartments. These functions require effective and adjustable mechanisms responsible for ascorbate biodistribution. In the paper we propose a new biophysical model of ascorbate redistribution between various aqueous body compartments. It combines recent experimental evidence regarding the ability of ascorbate to cross the lipid bilayer by unassisted diffusion, with active transport by well-characterized sodium vitamin C transporter (SVCT) membrane proteins. In the model, the intracellular concentration of ascorbate is maintained by the balance of two opposing fluxes: fast active and slow passive transport. The model provides a mechanistic understanding of ascorbate flux across the epidermal barrier in the gut as well as the role of astrocytes in ascorbate recycling in the brain. In addition, ascorbate passive diffusion across biological membranes, which depends on membrane electric potentials and pH gradients, provides the rationale for the correlation between ascorbate distribution and the transfer of iron ions inside a cell. The proposed approach provides, for the first time, a mechanistic account of processes leading to ascorbate physiological and cellular distribution, which helps to explain numerous experimental and clinical observations.

Developmental lead (Pb)-induced deficits in redox and bioenergetic status of cerebellar synapses are ameliorated by ascorbate supplementation

Neurotoxicity induced by exposure to heavy metal lead (Pb) is a concern of utmost importance particularly for countries with industrial-based economies. The developing brain is especially sensitive to exposure to even minute quantities of Pb which can alter neurodevelopmental trajectory with irreversible effects on motor, emotive-social and cognitive attributes even into later adulthood. Chemical synapses form the major pathway of inter-neuronal communications and are prime candidates for higher order brain (motor, memory and behavior) functions and determine the resistance/susceptibility for neurological disorders, including neuropsychopathologies. The synaptic pathways and mechanisms underlying Pb-mediated alterations in neuronal signaling and plasticity are not completely understood. Employing a biochemically isolated synaptosomal fraction which is enriched in synaptic terminals and synaptic mitochondria, this study aimed to analyze the alterations in bioenergetic and redox/antioxidant status of cerebellar synapses induced by developmental exposure to Pb (0.2 %). Moreover, we test the efficacy of vitamin C (ascorbate; 500 mg/kg body weight), a neuroprotective and neuromodulatory antioxidant, in mitigation of Pb-induced neuronal deficits. Our results implicate redox and bioenergetic disruptions as an underlying feature of the synaptic dysfunction observed in developmental Pb neurotoxicity, potentially contributing to consequent deficits in motor, behavioral and psychological attributes of the organisms. In addition, we establish ascorbate as a key ingredient for therapeutic approach against Pb induced neurotoxicity, particularly for early-life exposures.

Comparison of serum microbiome composition in bipolar and major depressive disorders

Bipolar disorder and major depressive disorder are debilitating psychiatric conditions which can be difficult to differentiate; however, recent studies have suggested that microbiome composition may be a potential tool in distinguishing between these two disorders. This study aimed to compare the serum microbiome composition of patients with bipolar disorder, major depressive disorder, and healthy controls. Serum samples were collected from 42 subjects with bipolar disorder, 30 with major depressive disorder, and 36 healthy controls. Bacterial DNA was isolated from bacteria-derived extracellular vesicles in the serum and then amplified and quantified with primers specific to the V3-V4 hypervariable region of the 16S rDNA gene. Sequence reads were clustered into operational taxonomic units and classified using the SILVA database. Alpha and beta diversity, individual taxa analysis based on phylum and genus, and functional pathways were compared. There was no statistical difference between alpha or beta diversity in patients with bipolar disorder and major depressive disorder; however, the Prevotella 2 and Ruminococcaceae UCG-002 genera were significantly more prevalent in patients with major depressive disorder than in either those with bipolar disorder or in healthy controls. Functional analysis of pathways revealed that the apoptosis function differed between all three groups. In conclusion, the Prevotella 2 and Ruminococcaceae UCG-002 genera were identified as potential candidates for distinguishing bipolar disorder and major depressive disorder. Further studies with larger sample sizes, longitudinal designs, and control for other various confounders are warranted.

Neurobiology of vitamin C: Expanding the focus from antioxidant to endogenous neuromodulator

Ascorbic acid (AA) is a water-soluble vitamin (C) found in all bodily organs. Most mammals synthesize it, humans are required to eat it, but all mammals need it for healthy functioning. AA reaches its highest concentration in the brain where both neurons and glia rely on tightly regulated uptake from blood via the glucose transport system and sodium-coupled active transport to accumulate and maintain AA at millimolar levels. As a prototype antioxidant, AA is not only neuroprotective, but also functions as a cofactor in redox-coupled reactions essential for the synthesis of neurotransmitters (e.g., dopamine and norepinephrine) and paracrine lipid mediators (e.g., epoxiecoisatrienoic acids) as well as the epigenetic regulation of DNA. Although redox capacity led to the promotion of AA in high doses as potential treatment for various neuropathological and psychiatric conditions, ample evidence has not supported this therapeutic strategy. Here, we focus on some long-neglected aspects of AA neurobiology, including its modulatory role in synaptic transmission as demonstrated by the long-established link between release of endogenous AA in brain extracellular fluid and the clearance of glutamate, an excitatory amino acid. Evidence that this link can be disrupted in animal models of Huntington´s disease is revealing opportunities for new research pathways and therapeutic applications (e.g., epilepsy and pain management). In fact, we suggest that improved understanding of the regulation of endogenous AA and its interaction with key brain neurotransmitter systems, rather than administration of AA in excess, should be the target of future brain-based therapies.

Distinctive Neurochemistry in Alzheimer's Disease via 7 T In Vivo Magnetic Resonance Spectroscopy

This study's objective was to increase understanding of biological mechanisms underlying clinical Alzheimer's disease (AD) by noninvasively measuring an expanded neurochemical profile and exploring how well this advanced technology distinguishes AD from cognitively normal controls. We measured concentrations of 14 neurochemicals using ultra-high field (7 T) ultra-short echo time (8 ms) magnetic resonance spectroscopy (MRS) in 16 participants with mild to moderate clinical AD and 33 age- and gender-matched control participants. MRS was localized to the posterior cingulate cortex (PCC), a region known to be impacted by AD, and the occipital cortex (OCC), a control region. Participants with AD were recruited from dementia specialty clinics. Concentration of the antioxidant ascorbate was higher (p < 0.0007) in both brain regions. Concentrations of the glial marker myo-inositol and the choline-containing compounds involved in membrane turnover were higher (p≤0.0004) in PCC of participants with AD. Ascorbate and myo-inositol concentrations were strongly associated, especially in the PCC. Random forests, using the 14 neurochemicals in the two regions, distinguished participants with AD from controls: same-sample sensitivity and specificity were 88% and 97%, respectively, though out-of-sample-values would be lower. Ultra-high field ultra-short echo time MRS identified the co-occurrence of elevated ascorbate and myo-inositol in the PCC as markers that distinguish participants with mild to moderate AD from controls. While elevated myo-inositol may be a surrogate marker of neuroinflammation, the unexpected elevation of the antioxidant ascorbate may reflect infiltration of ascorbate-rich leukocytes.

Novel Targets for Fast Antidepressant Responses: Possible Role of Endogenous Neuromodulators

The available medications for the treatment of major depressive disorder have limitations, particularly their limited efficacy, delayed therapeutic effects, and the side effects associated with treatment. These issues highlight the need for better therapeutic agents that provide more efficacious and faster effects for the management of this disorder. Ketamine, an N-methyl-D-aspartate receptor antagonist, is the prototype for novel glutamate-based antidepressants that has been shown to cause a rapid and sustained antidepressant effect even in severe refractory depressive patients. Considering the importance of these findings, several studies have been conducted to elucidate the molecular targets for ketamine's effect. In addition, efforts are under way to characterize ketamine-like drugs. This review focuses particularly on evidence that endogenous glutamatergic neuromodulators may be able to modulate mood and to elicit fast antidepressant responses. Among these molecules, agmatine and creatine stand out as those with more published evidence of similarities with ketamine, but guanosine and ascorbic acid have also provided promising results. The possibility that these neuromodulators and ketamine have common neurobiological mechanisms, mainly the ability to activate mechanistic target of rapamycin and brain-derived neurotrophic factor signaling, and synthesis of synaptic proteins in the prefrontal cortex and/or hippocampus is presented and discussed.

Dysfunction of cortical synapse-specific mitochondria in developing rats exposed to lead and its amelioration by ascorbate supplementation

BACKGROUND

Lead (Pb) is a widespread environmental neurotoxin and its exposure even in minute quantities can lead to compromised neuronal functions. A developing brain is particularly vulnerable to Pb mediated toxicity and early-life exposure leads to permanent alterations in brain development and neuronal signaling and plasticity, culminating into cognitive and behavioral dysfunctions and elevated risk of neuropsychiatric disorders later in life. Nevertheless, the underlying biochemical mechanisms have not been completely discerned.

METHODS

Because of their ability to fulfill high energy needs and to act as calcium buffers in events of high intensity neuronal activity as well as their adaptive regulatory capability to match the requirements of the dynamicity of synaptic signaling, synapse-specific or synaptic mitochondria (SM) are critical for synaptic development, function and plasticity. Our aim for the present study hence was to characterize the effects of early-life Pb exposure on the functions of SM of prepubertal rats. For this purpose, employing a chronic model of Pb neurotoxicity, we exposed rat pups perinatally and postnatally to Pb and used a plethora of colorimetric and fluorometric assays for assessing redox and bioenergetic properties of SM. In addition, taking advantage of its ability as an antioxidant and as a metal chelator, we employed ascorbic acid (vitamin C) supplementation as an ameliorative therapeutic strategy against Pb-induced neurotoxicity and dysfunction of SM.

RESULTS

Our results suggest that early-life exposure to Pb leads to elevated oxidative stress in cortical SM with consequent compromises in its energy metabolism activity. Ascorbate supplementation resulted in significant recovery of Pb-induced oxidative stress and functional compromise of SM.

CONCLUSION

Alterations in redox status and bioenergetic properties of SM could potentially contribute to the synaptic dysfunction observed in events of Pb neurotoxicity. Additionally, our study provides evidence for suitability of ascorbate as a significant ameliorative agent in tacking Pb neurotoxicity.

Developmental lead (Pb)-induced deficits in hippocampal protein translation at the synapses are ameliorated by ascorbate supplementation

BACKGROUND

Lead (Pb) is a persistent environmental neurotoxin and its exposure even in minute quantities has been known to induce neuronal defects. The immature brain is singularly sensitive to Pb neurotoxicity, and its exposure during development has permanent detrimental effects on the brain developmental trajectory and neuronal signaling and plasticity, culminating into compromises in the cognitive and behavioral attributes which persists even later in adulthood. Several molecular pathways have been implicated in the Pb-mediated disruption of neuronal signaling, including elevated oxidative stress, alterations in neurotransmitter biology, and mitochondrial dysfunction. Nevertheless, the neuronal targets and biochemical pathways underlying these Pb-mediated alterations in synaptic development and function have not been completely deduced. In this respect, recent studies have shown that synaptic signaling and its maintenance and plasticity are critically dependent on localized de novo protein translation at the synaptic terminals.

MATERIALS AND METHODS

The present study hence aimed to assess the alterations in the synapse-specific translation induced by developmental Pb exposure. To this end, in vitro protein translation rate was analyzed in the hippocampal synaptoneurosomal fractions of rat pups pre- and postnatally exposed to Pb using a puromycin incorporation assay. Moreover, we evaluated the therapeutic effects of ascorbic acid supplementation against Pb-induced deficits in synapse-localized protein translation.

RESULTS

We observed a significant loss in the rates of de novo protein translation in synaptoneurosomes of Pb-exposed pups compared to age-matched control pups. Interestingly, ascorbate supplementation lead to an appreciable recovery in Pb-induced translational deficits. Moreover, the deficit in activity-dependent synaptic protein translation was found to correlate significantly with the increase in the blood Pb levels.

CONCLUSION

Dysregulation of synapse-localized de novo protein translation is a potentially critical determinant of Pb-induced synaptic dysfunction and the consequent deficits in behavioral, social, and psychological attributes of the organisms. In addition, our study establishes ascorbate supplementation as a key ameliorative agent against Pb-induced neurotoxicity.