The impact of vitamin D deficiency on neurogenesis in the adult brain

Vitamin D3 improves iminodipropionitrile-induced tic-like behavior in rats through regulation of GDNF/c-Ret signaling activity

Children with chronic tic disorders (CTD), including Tourette syndrome (TS), have significantly reduced serum 25-hydroxyvitamin D [25(OH)D]. While vitamin D3 supplementation (VDS) may reduce tic symptoms in these children, its mechanism is unclear. The study aim was to investigate the effects and mechanisms of vitamin D deficiency (VDD) and VDS on TS model behavior. Forty 5-week-old male Sprague-Dawley rats were randomly divided into (n = 10 each): control, TS model, TS model with VDD (TS + VDD), or TS model with VDS (TS + VDS; two intramuscular injections of 20,000 IU/200 g) groups. The VDD model was diet-induced (0 IU vitamin D/kg); the TS model was iminodipropionitrile (IDPN)-induced. All groups were tested for behavior, serum and striatal 25(OH)D and dopamine (DA), mRNA expressions of vitamin D receptor (VDR), glial cell line-derived neurotrophic factor (GDNF), protooncogene tyrosine-protein kinase receptor Ret (c-Ret), and DA D1 (DRD1) and D2 (DRD2) receptor genes in the striatum. TS + VDD had higher behavior activity scores throughout, and higher total behavior score at day 21 compared with TS model. In contrast, day 21 TS + VDS stereotyped behavior scores and total scores were lower than TS model. The serum 25(OH)D in TS + VDD was < 20 ng/mL, and lower than control. Striatal DA of TS was lower than control. Compared with TS model, striatal DA of TS + VDD was lower, while in TS + VDS it was higher than TS model. Furthermore, mRNA expression of VDR, GDNF, and c-Ret genes decreased in TS model, and GDNF expression decreased more in TS + VDD, while TS + VDS had higher GDNF and c-Ret expressions. VDD aggravates, and VDS ameliorates tic-like behavior in an IDPN-induced model. VDS may upregulate GDNF/c-Ret signaling activity through VDR, reversing the striatal DA decrease and alleviating tic-like behavior.

Molecular Regulation of the CNS by Vitamin D

Vitamin D is a lipid-soluble vitamin that can be found in some foods. It is also produced endogenously (in the presence of ultraviolet light), transported through the blood to the targets organs and this is the reason to consider vitamin D as a hormone. It is known that vitamin D has genomic and non-genomic effects. This review is focused mainly on the vitamin D receptors, the importance of vitamin D as a neuromodulator, the role of vitamin D in the pathophysiology of devastating neurological disorders such as Alzheimer's disease, multiple sclerosis, amyotrophic lateral sclerosis, Parkinson's disease and the benefit of vitamin D and its derivates in alleviating these disorders.

Oral calcium and vitamin D supplements differentially alter exploratory, anxiety-like behaviors and memory in male rats

Oral calcium and calcium plus vitamin D supplements are commonly prescribed to several groups of patients, e.g., osteoporosis, fracture, and calcium deficiency. Adequate and steady extracellular calcium levels are essential for neuronal activity, whereas certain forms of calcium supplement (e.g., CaCO3) probably interfere with memory function. However, it was unclear whether a long-term use of ionized calcium (calcium chloride in drinking water ad libitum), vitamin D supplement (oral gavage) or the combination of both affected anxiety and memory, the latter of which was probably dependent on the hippocampal neurogenesis. Here, we aimed to determine the effects of calcium and/or vitamin D supplement on the anxiety- and memory-related behaviors and the expression of doublecortin (DCX), an indirect proxy indicator of hippocampal neurogenesis. Eight-week-old male Wistar rats were divided into 4 groups, i.e., control, calcium chloride-, 400 UI/kg vitamin D3-, and calcium chloride plus vitamin D-treated groups. After 4 weeks of treatment, anxiety-, exploration- and recognition memory-related behaviors were evaluated by elevated pulse-maze (EPM), open field test (OFT), and novel object recognition (NOR), respectively. The hippocampi were investigated for the expression of DCX protein by Western blot analysis. We found that oral calcium supplement increased exploratory behavior as evaluated by OFT and the recognition index in NOR test without any effect on anxiety behavior in EPM. On the other hand, vitamin D supplement was found to reduce anxiety-like behaviors. Significant upregulation of DCX protein expression was observed in the hippocampus of both calcium- and vitamin D-treated rats, suggesting their positive effects on neurogenesis. In conclusion, oral calcium and vitamin D supplements positively affected exploratory, anxiety-like behaviors and/or memory in male rats. Thus, they potentially benefit on mood and memory in osteoporotic patients beyond bone metabolism.

Understanding the Immune-Endocrine Effects of Vitamin D in SARS-CoV-2 Infection: A Role in Protecting against Neurodamage

Calcitriol and hydroxyderivatives of lumisterol and tachisterol are secosteroid hormones with immunomodulatory and anti-inflammatory properties. Since the beginning of the COVID-19 pandemic, several studies have correlated deficient serum concentrations of vitamin D3 (calcifediol) with increased severity of the course of SARS-CoV-2 infection. Among systemic complications, subjective (anosmia, ageusia, depression, dizziness) and objective (ischemic stroke, meningoencephalitis, myelitis, seizures, Guillain-Barré syndrome) neurological symptoms have been reported in up to 80% of severe COVID-19 patients. In this narrative review, we will resume the pathophysiology of SARS-CoV-2 infection and the mechanisms of acute and chronic neurological damage. SARS-CoV-2 can disrupt the integrity of the endothelial cells of the blood-brain barrier (BBB) to enter the nervous central system. Invasion of pro-inflammatory cytokines and polarization of astrocytes and microglia cells always in a pro-inflammatory sense together with the pro-coagulative phenotype of cerebral endothelial cells in response to both SARS-CoV-2 and immune cells invasion (immunothrombosis) are the major drivers of neurodamage. Calcitriol and hydroxyderivatives of lumisterol and tachisterol could play an adjuvant role in neuroprotection through mitigation of neuroinflammation and protection of endothelial integrity of the BBB. Dedicated studies on this topic are currently lacking and are desirable to confirm the link between vitamin D3 and neuroprotection in COVID-19 patients.

Vitamin D status and tic disorder: a systematic review and meta-analysis of observational studies

Objective

Tic disorders (TD) are a common neurodevelopmental disorder, it can be divided into transient tic disorder (TTD), chronic motor or vocal tic disorder (CTD), and Tourette syndrome (TS). Our research is to evaluate the clinical relationship between tic disorders and vitamin D level in children.

Methods

Online databases, including CNKI, Wanfang, VIP, Cochrane Library, PubMed and Embase digital knowledge service platform, were checked up to June 2022 for relevant observational studies published in Chinese and English. A random-effects model was incorporated to summarize the study results. The RevMan5.3 software was used for meta-analysis.

Results

Out of 132 retrieved articles, 13 observational studies were eligible for inclusion in the systematic review and meta-analysis, comparing serum Vitamin D levels between children with TD and HC (healthy controls), including different subtypes of TD (TTD, CTD and TS). The results showed that the serum vitamin D levels in the TD group were lower than those in the HC group (MD = -6.64, 95% CI: -9.36 to -3.93, P < 0.001, Heterogeneity test: P < 0.001, I² = 94%). There were no statistically significant differences in serum vitamin D levels between the TTD group and the CTD group (MD = 3.84, 95% CI: -0.59 to 8.26, P = 0.09, Heterogeneity test: P < 0.001, I² = 90%), or between the CTD group and the TS group (MD = 1.06, 95% CI: -0.04 to 2.16, P = 0.0, Heterogeneity test: P = 0.54, I² = 0%). However, there was a statistically significant difference in serum vitamin D levels between the TTD group and the TS group (MD = 5.24, 95% CI: 0.68-9.80, P = 0.02, Heterogeneity test: P < 0.001, I² = 92%). The study also found a statistically significant difference in the ratio of male children between the TD group and the HC group (OR = 1.48, 95% CI: 1.07-2.03, P = 0.02, Heterogeneity test: P < 0.001, I² = 74%), but no statistically significant difference in the age of children between the TD group and the HC group (OR = 0.46, 95% CI: -0.33 to 1.24, P = 0.25, Heterogeneity test: P < 0.001, I² = 96%).

Conclusions

Our meta-analysis showed that the vitamin D level of children with TD was lower than that of healthy children. However, there was no difference between the subgroup. Due to the limitations of included studies in research design and diagnostic criteria, large samples, multi-center and high-quality studies are still needed for further analysis and confirmation.

Behavioral sleep medicine-The need for harmonization of clinical best practice outcome measures in children and adolescents with intellectual or developmental disabilities and restless sleep

In behavioral medicine, sleep disorders, insomnia in particular, may be considered comorbidities and precipitating factors to intellectual or developmental disabilities (IDD). Nevertheless, sleep alterations have often been neglected in favor of daytime features and symptoms, albeit simple behavioral nighttime observations may disclose hypermotor features that characterize restless sleep. The root of most hypermotor restlessness is linked to central iron deficiency. The latter is often exacerbated by vitamin D deficiency (VDD), which interferes with both dopaminergic and serotonergic mechanisms. In this way, an imbalance affecting daytime behavior and mood is created. Several sleep-related motor disorders such as bruxism, periodic and aperiodic leg movements, Restless Legs Syndrome (RLS), and Restless Sleep Disorder (RSD) are commonly seen in Attention Deficit Hyperactivity Disorder (ADHD) and Autism Spectrum Disorders (ASD). However, they are rarely diagnosed and often overlooked in affected children and adolescents. As a result, not only are these disorders not adequately addressed therapeutically, but their symptoms may be worsened by the side-effects of drugs used to contain disruptive daytime behavior, such as antipsychotics and antidepressants. In children with IDDs, obesity, inactivity and metabolic effects of antipsychotics often lead to Sleep Disordered Breathing (SDB), which is currently understood as an inflammatory state leading to "hyperactive" lethargy and further alterations of the hypoxic chain and vitamin D levels. Endorsing simple routine blood tests, including inflammatory markers such as C-reactive protein, ferritin, transferrin, and vitamin D levels, may favorably complement caregiver observations and ambulatory sleep recordings, leading to a sleep disorder diagnosis and consequent therapy. In fact, the treatment of SDB, RLS, and RSD has been copiously demonstrated to favorably impact vigilance, behavior, social competence, and academic skills in healthy and, to a greater extent, in IDD children. Thus, consulting and deliberating the root causes of functional and categorical diagnoses within a clinical framework may engender a more precise diagnosis and further benefit pediatric daytime and nighttime management of hyperactive behaviors.

Prospective associations between vitamin D and depression in middle-aged adults: findings from the UK Biobank cohort

BACKGROUND

A possible role of vitamin D in the pathophysiology of depression is currently speculative, with more rigorous research needed to assess this association in large adult populations. The current study assesses prospective associations between vitamin D status and depression in middle-aged adults enrolled in the UK Biobank.

METHODS

We assessed prospective associations between vitamin D status at the baseline assessment (2006-2010) and depression measured at the follow-up assessment (2016) in 139 128 adults registered with the UK Biobank.

RESULTS

Amongst participants with no depression at baseline (n = 127 244), logistic regression revealed that those with vitamin D insufficiency [adjusted odds ratio (aOR) = 1.14, 95% confidence interval (CI) = 1.07-1.22] and those with vitamin D deficiency (aOR = 1.24, 95% CI 1.13-1.36) were more likely to develop new-onset depression at follow-up compared with those with optimal vitamin D levels after adjustment for a wide range of relevant covariates. Similar prospective associations were reported for those with depression at baseline (n = 11 884) (insufficiency: aOR = 1.11, 95% CI 1.00-1.23; deficiency: aOR = 1.30, 95% CI 1.13-1.50).

CONCLUSIONS

The prospective associations found between vitamin D status and depression suggest that both vitamin D deficiency and insufficiency might be risk factors for the development of new-onset depression in middle-aged adults. Moreover, vitamin D deficiency (and to a lesser extent insufficiency) might be a predictor of sustained depressive symptoms in those who are already depressed. Vitamin D deficiency and insufficiency is very common, meaning that these findings have significant implications for public health.

Impulsivity and eating disorders: The relationship between serum 25-hydroxyvitamin D and different impulsivity facets in a transdiagnostic sample

OBJECTIVES

Eating disorders (EDs) are severe psychiatric conditions characterised by malnutrition, dysfunctional behaviours, and hypovitaminosis D. In various psychiatric conditions, including EDs, preliminary evidence has correlated impulsivity to a low level of 25-hydroxyvitamin D [25(OH)D]. This study aims to reinforce this evidence by examining different facets, both behavioural and psychological, of the impulsivity construct in patients with ED.

METHODS

A sample of 119 women was evaluated with a validated questionnaire and computerised neuropsychological tasks: the UPPS-P impulsive behaviour scale, a go/no-go task, and the Balloon Analogue Risk Task (BART). A clinical evaluation for EDs and blood sample collection were also performed to assess specific psychopathology and determine the serum level of 25(OH)D.

RESULTS

Significant correlations were found between serum levels of 25(OH)D and BART scores (p = 0.012) and lack of perseverance (p = 0.034). Moreover, regression analyses showed that higher BART scores may be explained by hypovitaminosis D and higher levels of lack of perseverance in patients with EDs.

CONCLUSIONS

The specific aspect of impulsivity linked to goal strategy and behaviours may be explained in patients with EDs by hypovitaminosis D. A possible connection to the brain inflammatory system is also discussed, along with possible directions for future research.

Sex Differences in Vitamin D Status as a Risk Factor for Incidence of Disability in Instrumental Activities of Daily Living: Evidence from the ELSA Cohort Study

Vitamin D deficiency compromises elements underlying the disability process; however, there is no evidence demonstrating the association between vitamin D deficiency and the incidence of disability in instrumental activities of daily living (IADL). We investigated the association between vitamin D deficiency and the risk of incidence of IADL disability separately in men and women. A total of 4768 individuals aged ≥50 years from the English Longitudinal Study of Aging (ELSA) and without IADL disability according to the Lawton scale were available. Vitamin D was evaluated at baseline by serum 25(OH)D concentrations and classified as sufficient (>50 nmol/L), insufficient (>30 to ≤50 nmol/L) or deficient serum (≤30 nmol/L). IADL were reassessed after 4 years. Poisson models stratified by sex and controlled by covariates demonstrated that deficient serum 25(OH)D was a risk factor for the incidence of IADL disability in men (IRR: 1.43; 95% CI 1.02, 2.00), but not in women (IRR: 1.23; 95% CI 0.94, 1.62). Men appear to be more susceptible to the effect of vitamin D deficiency on the incidence of IADL disability, demonstrating the importance of early clinical investigation of serum 25(OH)D concentrations to prevent the onset of disability.

Eggs Consumption in Relation to Lower Risk of Cognitive Impairment in Elderly: Findings from a 6-Year Cohort Study

OBJECTIVES

To evaluate the longitudinal association of eggs consumption with cognitive function in Chinese elderly.

DESIGN

Prospective cohort study.

PARTICIPANTS

9028 participants aged ≥60 years from Zhejiang Ageing and Health Cohort Study without cognitive impairment at baseline survey.

MEASUREMENTS

Cognitive function was assessed through the Mini-Mental State Examination (MMSE) at baseline and three waves of follow-up (2015, 2016, and 2019-2020). Data on eggs consumption was collected in the diet habits section within the questionnaire at baseline. Log-binomial regression models with the Generalized Estimating Equations, controlled for an extensive range of potential confounders, were used to evaluate the association and estimate relative risks (RRs).

RESULTS

After 6 years of follow-up, 3266 (36.18%) participants were indicated as cognitive impairment by MMSE at least once. Compared with non-consumers or less-than-weekly consumers, participants consuming 0.1-2.9 eggs/week and 3.0-5.9 eggs/week had 18% (RR=0.82, 95%CI 0.76-0.89) and 9% (RR=0.91, 95%CI 0.84-0.99) lower risks of cognitive impairment respectively, whereas no association was found in those consuming ≥6.0 eggs/week (P=0.32). Moreover, infrequent lower-quantity consumption (1-2 days/week and 0.1-1.9 eggs/day), infrequent higher-quantity consumption (1-2 days/week and ≥2.0 eggs/day), and frequent lower-quantity consumption (≥3 days/week and 0.1-1.9 eggs/day) were associated with better cognitive performance, whereas null association was found among frequent higher-quantity consumers (≥3 days/week and ≥2.0 eggs/day). The sensitivity analyses yielded consistent results to the main analysis.

CONCLUSION

Limited eggs consumption is prospectively related to a lower risk of cognitive impairment in Chinese elderly.

Therapeutic effect of acute and chronic use of different doses of vitamin D3 on seizure responses and cognitive impairments induced by pentylenetetrazole in immature male rats

Objective(s):

This study aimed to evaluate the effects of acute and chronic intake of different doses of vitamin D3 on seizure responses and cognitive impairment induced by pentylenetetrazole (PTZ) in immature male rats.

Materials and Methods:

Sixty-six immature male NMRI rats were divided into control (10), epileptic (10), and treatment groups (46). The stage 5 latency (S5L) and stage 5 duration (S5D) were assessed along with the shuttle box test. Levels of antioxidant enzymes and inflammatory factors along with genes involved in inflammation, oxidative damage, apoptosis, and mTORc1 were measured in the hippocampus tissue of the brain of controlled and treated rats. Serum levels of parathyroid hormone (PTH), vitamin D, calcium, and phosphorus were also assessed.

Results:

The results showed that the ability to learn, memory consolidation, and memory retention in epileptic rats were reduced. In addition, S5D increased and S5L decreased in epileptic rats, while being effectively ameliorated by chronic and acute vitamin D intake. The results showed that vitamin D in different doses acutely and chronically decreased the levels of oxidative and inflammatory biomarkers in hippocampus tissue and inhibited the expression of genes involved in inflammation, oxidative damage, apoptosis, and mTORc1 in the hippocampus tissue of epileptic rats.

Conclusion:

The results showed that vitamin D in different doses acutely and chronically could improve cognitive impairments and convulsive responses in epileptic rats by improving neurotransmission, inflammation, apoptosis, and oxidative damage.

Correlation Between Tic Disorders and Serum 25-Hydroxyvitamin D Levels in Chinese Children

OBJECTIVE

To explore the correlation between serum 25-hydroxyvitamin D levels and tic disorders (TDs) in Chinese children.

METHODS

We selected 2960 children with TD and 2665 healthy controls, aged 5-14 years, from the Department of Neurology of the Shanghai Children's Hospital. Serum 25-hydroxyvitamin D levels and degrees of vitamin D deficiency were compared between patients with TD and healthy children.

RESULTS

The mean serum 25-hydroxyvitamin D level in the TD group was significantly lower than that in the control group (P < 0.001). The proportion of patients with 25-hydroxyvitamin D deficiency in the TD group was significantly higher than that in the control group. However, there was no correlation between 25-hydroxyvitamin D deficiency and the severity of TD. In addition, for age-wise comparison, mean levels of 25-hydroxyvitamin D and its deficiency in the TD group were the most significant in children over 9 years of age.

CONCLUSION

There is a correlation between 25-hydroxyvitamin D deficiency and TD in Chinese children, but not between 25-hydroxyvitamin D deficiency and the severity of TD. There was a correlation between age and deficiency of 25-hydroxyvitamin D; this deficiency was most pronounced among those over the age of 9 years.

Smell Regions in Patients with Vitamin D Deficiency: An MRI Evaluation

Objective  We investigated the effects of vitamin D deficiency in the peripheral and central smell regions by magnetic resonance imaging (MRI). Methods  This retrospective study included 29 patients (12 males, 17 females) with 25-dihydroxy vitamin D3 [25(OH) ₂ D ₃ ] deficiency (group 1) and 34 subjects without 25(OH) ₂ D ₃ deficiency (14 males, 20 females) (group 2). Using cranial MRIs, the peripheral (olfactory bulb [OB] volume and olfactory sulcus [OS] depth) and central (insular gyrus and corpus amygdala) smell regions were evaluated. Results  The OB volume and OS depth values of the 25(OH) ₂ D3 deficiency group were significantly lower than those of the control group ( p  < 0.05). For the central smell regions, the insular gyrus and corpus amygdala areas of the 25(OH) ₂ D3 deficiency group were nonsignificantly lower than those in the control group ( p  > 0.05). There were positive correlations between OB volumes, OS depths, and insular gyrus and corpus amygdala areas bilaterally in the 25(OH) ₂ D3 deficiency group separately and in all subjects (groups 1 and 2) ( p  < 0.05). In the 25(OH) ₂ D3 deficiency group, as the 25(OH) ₂ D3 values became lower, the insular gyrus area values decreased bilaterally ( p  < 0.05). In females, the corpus amygdala area values were lower than in males ( p  < 0.05). Conclusion  Since vitamin D3 deficiency affected the peripheral and central smell regions negatively, we recommend evaluating patients' vitamin D levels as a health policy to prevent vitamin D3 deficiency-related cranial smell region problems. Moreover, sunlight exposure is very important to increase vitamin D levels, and the public should be informed about this topic.

Association of magnesium intake and vitamin D status with cognitive function in older adults: an analysis of US National Health and Nutrition Examination Survey (NHANES) 2011 to 2014

PURPOSE

Reduced cognitive function associated with aging has gained increasing attention as the US population ages. Magnesium plays a critical role in vitamin D biosynthesis and metabolism; and deficiencies in magnesium and vitamin D show associations with poor cognition. However, no study has examined their interaction. This study aimed to evaluate the associations of magnesium intake and serum 25-hydroxyvitamin D (25(OH)D) concentrations, indicating vitamin D status, with cognition, and interaction between these nutrients in older adults.

METHODS

Based on the National Health and Nutrition Survey (NHANES) 2011-2014, the study included 2466 participants aged ≥ 60 years who completed the Digit Symbol Substitution Test (DSST) and had data available on serum 25(OH)D and magnesium intake. Cognitive impairment was defined as a DSST score lower than the lowest quartile. Serum 25(OH)D concentrations were measured by HPLC-tandem mass spectrometry.

RESULTS

Higher total magnesium intake was independently associated with higher DSST scores (highest quartile vs lowest: β = 4.34, 95% CI 1.14-7.54). The association of total magnesium intake with high DSST score was primarily observed among women, non-Hispanic whites, physically active participants and those with sufficient vitamin D status, although the interactions were not significant. The odds of cognitive impairment was reduced with increasing intake of total magnesium (p trend < 0.01) and higher level of serum 25(OH)D (p trend = 0.05).

CONCLUSIONS

Findings suggest that high magnesium intake alone may improve cognitive function in older adults, and the association may be stronger among subjects with sufficient vitamin D status. Further studies are needed to confirm these findings.

Vitamin D and advanced glycation end products and their receptors

Advanced glycation end products (AGEs) are destructive molecules in the body that, at high levels, contribute to the progression of various chronic diseases. Numerous studies have suggested a modifying effect of vitamin D on AGEs and their receptors. This study sought to summarize the effects of vitamin D on AGEs and their receptors, including receptor for AGEs (RAGE) and soluble receptor for AGEs (sRAGE). The search method initially identified 484 articles; 331 remained after duplicate removal. Thirty-five articles were screened and identified as relevant to the study topic. After critical analysis, 27 articles were included in the final analysis. Vitamin D treatment may possibly be beneficial to reduce AGE levels and to augment sRAGE levels, particularly in vitamin D-deficient situations. Treatment with this vitamin may be effective in reducing RAGE expression in some disease conditions, but might be even harmful under normal conditions. The inhibitory or stimulatory effects of vitamin D on AGE receptors are mediated by various signaling pathways, MAPK/NF-κB, ADAM10/MMP9 and AT1R. In populations with chronic diseases and concomitant hypovitaminosis D, vitamin D supplementation can be used as a strategy to ameliorate AGE-mediated complications by modifying the AGE-RAGE and sRAGE systems.

Vitamin D increases remyelination by promoting oligodendrocyte lineage differentiation

INTRODUCTION

Several experimental studies have suggested the potential remyelinating effects of vitamin D (VitD) supplements regardless of the presence of VitD deficiency. This study aims to analyze neurogenesis in a model of toxic demyelination in order to evaluate the effects of VitD on demyelination and remyelination.

MATERIAL AND METHODS

We used 24 male Wistar rats that had received surgical lesions to the corpus callosum and were injected with lysolecithin. Rats were divided into three groups: Group 1 included eight rats with lesions to the corpus callosum but not lysolecithin injections (sham group), group 2 included eight rats with lesions to the corpus callosum that were injected with lysolecithin (lysolecithin group), and group 3 included eight rats with lesions that were injected with lysolecithin and received VitD (VitD group). We analyzed neurogenesis both in the subventricular zone and at the lesion site.

RESULTS

Administration of VitD promotes the proliferation and differentiation of neural stem cells in the subventricular zone and the migration of these cells to the lesion site in the corpus callosum; these cells subsequently differentiate into oligodendrocyte lineage cells and produce myelin basic protein. This phenomenon was not caused by microglial activation, which was less marked in rats receiving VitD. Megalin expression did not increase at the lesion site, which suggests that VitD is internalized by other mechanisms.

CONCLUSION

Our results support the hypothesis that regardless of the presence of VitD deficiency, treatment with VitD may contribute to remyelination by promoting the proliferation of oligodendrocyte precursor cells.

Serum Levels of Vitamin A and Vitamin D and Their Association With Symptoms in Children With Attention Deficit Hyperactivity Disorder

Objective: To measure levels of vitamin A (VA) and vitamin D (VD) and the symptomatic association of their co-deficiencies on attention deficit hyperactivity disorder (ADHD) in Chinese children (6-9 years). Methods: Eighty-two children (69 boys and 13 girls; mean age = 7.1 ± 0.9 years at the time of the diagnosis) with ADHD were recruited as ADHD group. A total of 106 healthy children were recruited as the healthy control (HC) group. Serum levels of retinol and 25-hydroxyvitamin D (25(OH)D) of all children were evaluated using high-performance liquid chromatography (HPLC) and HPLC-tandem mass spectrometry. The Swanson, Nolan, and Pelham IV Rating Scale (SNAP-IV) was employed to assess the clinical symptoms of ADHD. Results: Children suffering from ADHD had significantly reduced serum levels of retinol and 25(OH)D compared with those of HCs, and the prevalence of VA deficiency and VD deficiency were higher in children suffering from ADHD. Serum concentrations of 25(OH)D and retinol were linked closely with the presence or absence of ADHD after adjustment for age, body mass index, season of blood sampling, and sun exposure. Serum concentrations of 25(OH)D and retinol showed a negative correlation with the total scores of SNAP-IV. Children with ADHD as well as VA and VD co-deficiency had increased SNAP-IV total scores and ADHD inattention subscale scores. Conclusion: VA deficiency and VD deficiency in children with ADHD were increased in comparison with that in HCs. VA and VD co-deficiency associated with ADHD symptom severity. Attention should be paid to regular testing of VA levels and VD levels. However, the mechanism of VA and VD in ADHD needs to be further studied. Interventional studies on VA and VD supplementation are recommended to further verify the relationship between VA and VD co-deficiency and ADHD.

Pharmacological, non-pharmacological and stem cell therapies for the management of autism spectrum disorders: A focus on human studies

In the last decade, the prevalence of autism spectrum disorders (ASD) has dramatically escalated worldwide. Currently available drugs mainly target some co-occurring symptoms of ASD, but are not effective on the core symptoms, namely impairments in communication and social interaction, and the presence of restricted and repetitive behaviors. On the other hand, transplantation of hematopoietic and mesenchymal stem cells in ASD children has been shown promising to stimulate the recruitment, proliferation, and differentiation of tissue-residing native stem cells, reducing inflammation, and improving some ASD symptoms. Moreover, several comorbidities have also been associated with ASD, such as immune dysregulation, gastrointestinal issues and gut microbiota dysbiosis. Non-pharmacological approaches, such as dietary supplementations with certain vitamins, omega-3 polyunsaturated fatty acids, probiotics, some phytochemicals (e.g., luteolin and sulforaphane), or overall diet interventions (e.g., gluten free and casein free diets) have been considered for the reduction of such comorbidities and the management of ASD. Here, interventional studies describing pharmacological and non-pharmacological treatments in ASD children and adolescents, along with stem cell-based therapies, are reviewed.

Neuronanotechnology for brain regeneration

Identifying and harnessing regenerative pathways while suppressing the growth-inhibiting processes of the biological response to injury is the central goal of stimulating neurogenesis after central nervous system (CNS) injury. However, due to the complexity of the mature CNS involving a plethora of cellular pathways and extracellular cues, as well as difficulties in accessibility without highly invasive procedures, clinical successes of regenerative medicine for CNS injuries have been extremely limited. Current interventions primarily focus on stabilization and mitigation of further neuronal death rather than direct stimulation of neurogenesis. In the past few decades, nanotechnology has offered substantial innovations to the field of regenerative medicine. Their nanoscale features allow for the fine tuning of biological interactions for enhancing drug delivery and stimulating cellular processes. This review gives an overview of nanotechnology applications in CNS regeneration organized according to cellular and extracellular targets and discuss future directions for the field.

Clinical improvement following vitamin D3 supplementation in children with chronic tic disorders

PURPOSE

Vitamin D deficiency has been found in children with chronic tic disorders (CTDs). Our previous data showed that serum 25-hydroxyvitamin D [25(OH)D] level in children with CTDs was lower than that of the healthy controls and lower serum 25(OH)D level was associated with increased severity of the tic disorder. Thus, we intend to further verify this phenomenon and examine the effect of vitamin D3 on CTDs.

PATIENTS AND METHODS

In total, 120 children with CTDs and 140 normal controls were enrolled in this study, with 36/120 of those in the CTD group receiving vitamin D3 treatment for 3 months. The Yale Global Tic Severity Scale (YGTSS) and Clinical Global Impression of Severity of Illness (CGI-SI) were, respectively, used to evaluate the tic severity. High-performance liquid chromatography and tandem mass spectrometry were used to measure serum 25(OH)D level.

RESULTS

Those children with CTDs exhibited significantly lower 25(OH)D levels than did healthy controls, and these reduced 25(OH)D levels were linked to increasing severity of tic symptoms. After treatment with supplemental vitamin D3, serum 25(OH)D level and scores of YGTSS total, motor tics, phonic tics, total tic, impairment, and CGI-SI improved significantly in children with CTDs without any adverse reactions.

CONCLUSION

Supplementation vitamin D3, given its low cost and excellent safety, may be an effective means of improving symptoms in certain children with CTDs.

Serum 25-hyroxyvitamin D levels and tic severity in Chinese children with tic disorders

The aim of this study is to evaluate serum 25-hydroxyvitamin D[25(OH)D] levels in children with tic disorders and to explore the relationship between serum 25(OH)D level and tic severity. Children (n = 179, 31 females, 148 males, mean age at diagnosis: 8.0 ± 2.7 years old, age ranged from 3 to 14.5 years old) who were diagnosed with a tic disorder were enrolled as case group, 189 healthy children were recruited as control group. Serum level of 25(OH)D of each child was measured by high performance liquid chromatography and tandem mass spectrometry (HPLC-MS/MS). Yale Global Tic Severity Scale (YGTSS) was used to assess tic severity. Mean serum level of 25(OH)D in the case group was significantly lower than that of the control group. The serum 25(OH)D level was significantly associated with tic severity after adjusting for age and body mass index (BMI). This study identified a high prevalence of vitamin D insufficiency or deficiency in children with tic disorders, and there was a negative correlation between the serum 25(OH)D level and tic severity. In the future, large sample size studies are urgently needed to further clarify this correlation.

Vitamin D protects dopaminergic neurons against neuroinflammation and oxidative stress in hemiparkinsonian rats

BACKGROUND

The deficiency in 1α, 25-dihydroxyvitamin D3 (VD3) seems to increase the risk for neurodegenerative pathologies, including Parkinson's disease (PD). The majority of its actions are mediated by the transcription factor, VD3 receptor (VD3R).

METHODS

The neuroprotective effects of VD3 were investigated on a PD model. Male Wistar rats were divided into the following groups: sham-operated (SO), 6-OHDA-lesioned (non-treated), and 6-OHDA-lesioned and treated with VD3 (7 days before the lesion, pre-treatment or for 14 days after the 6-OHDA striatal lesion, post-treatment). Afterwards, the animals were subjected to behavioral tests and euthanized for striatal neurochemical and immunohistochemical assays. The data were analyzed by ANOVA and the Tukey test and considered significant for p < 0.05.

RESULTS

We showed that pre- or post-treatments with VD3 reversed behavioral changes and improved the decreased DA contents of the 6-OHDA group. In addition, VD3 reduced the oxidative stress, increased (TH and DAT), and reduced (TNF-alpha) immunostainings in the lesioned striata. While significant decreases in VD3R immunoreactivity were observed after the 6-OHDA lesion, these changes were blocked after VD3 pre- or post-treatments. We showed that VD3 offers neuroprotection, decreasing behavioral changes, DA depletion, and oxidative stress. In addition, it reverses partially or completely TH, DAT, TNF-alpha, and VD3R decreases of immunoreactivities in the non-treated 6-OHDA group.

CONCLUSIONS

Taken together, VD3 effects could result from its anti-inflammatory and antioxidant actions and from its actions on VD3R. These findings should stimulate translational research towards the VD3 potential for prevention or treatment of neurodegenerative diseases, as PD.

Relationship between cumulative ultraviolet exposure and cognitive function in a rural elderly Chinese population

OBJECTIVES

Some researchers have focused on the relationship between vitamin D and cognition, but the conclusions are inconsistent. We estimated cumulative UV exposure could be used to represent the individual's long-term vitamin D status and investigated its association with global cognitive function in elderly Chinese.

METHODS

A total of 641 participants aged 60 years and over were recruited in a rural area of Shenyang, China. All were interviewed to obtain data regarding sociodemographic characteristics and time spent outdoors. Cognitive function was evaluated using the Montreal Cognitive Assessment-Beijing version (MoCA-BJ). Images of skin from UV-exposed (dorsal hand) and UV-protected (inner forearm) sites from each individual were graded by the Beagley-Gibson system. Differences in skin-grade between the 2 sites were used to indicate cumulative UV exposure level. Subjects were grouped in tertiles based on skin-grade differences (<1.75, 1.75-2.74, and ≥ 2.75), representing low, medium, and high UV exposure levels, respectively. The MoCA-BJ score was classified in tertiles as low (<19), middle (19-22), and high (≥23) levels of cognition. Associations between cognitive function and UV exposure were analyzed using ordinal regression.

RESULTS

Skin-grade differences were associated with self-reported time spent outdoors. After adjustment for age, gender, education, BMI, whether living alone, income, diet, hypertension, and diabetes, a high UV exposure level was associated with better cognitive function (odds ratio = 0.643, 95% confidence interval = 0.427-0.969).

CONCLUSIONS

Greater cumulative UV exposure appears to be associated with better cognitive function in elderly adults.

[Serum levels of 25-hydroxyvitamin D in children with tic disorders]

OBJECTIVE

To examine serum 25-hydroxyvitamin D levels in children with tic disorders (TD) and to explore the relationship between vitamin D level and TD.

METHODS

One hundred and thirty-two children who were diagnosed with TD between November 2016 and May 2017 were enrolled as the TD group, including 8 cases of Tourette syndrome, 32 cases of chronic TD, and 92 cases of transient TD. One hundred and forty-four healthy children served as the control group. Peripheral venous blood samples were collected from each child. Serum levels of 25-hydroxyvitamin D were measured using HPLC-MS/MS. The categories of vitamin D status based on serum 25-hydroxyvitamin D level included: normal (>30 ng/mL), insufficiency (10-30 ng/mL) and deficiency (<10 ng/mL).

RESULTS

Mean serum level of 25-hydroxyvitamin D in the TD group was significantly lower than that in the control group (P<0.01). The rate of vitamin D insufficiency or deficiency in the TD group was significantly higher than in the control group (P<0.01). Mean serum level of 25-hydroxyvitamin D in the transient tic group was higher than in the TS group (P<0.05).

CONCLUSIONS

Vitamin D insufficiency or deficiency might be associated with the development of TD, and the level of serum 25-hydroxyvitamin D might be related to the classification of TD.

A Systematic Review and Meta-Analysis of The Effect of Low Vitamin D on Cognition

BACKGROUND/OBJECTIVE

With an aging population and no cure for dementia on the horizon, risk factor modification prior to disease onset is an urgent health priority. Therefore, this review examined the effect of low vitamin D status or vitamin D supplementation on cognition in midlife and older adults without a diagnosis of dementia.

DESIGN

Systematic review and random effect meta-analysis.

SETTING

Observational (cross-sectional and longitudinal cohort) studies comparing low and high vitamin D status and interventions comparing vitamin D supplementation with a control group were included in the review and meta-analysis.

PARTICIPANTS

Studies including adults and older adults without a dementia diagnosis were included.

MEASUREMENTS

Medline (PubMed), AMED, Psych INFO, and Cochrane Central databases were searched for articles until August 2016. The Newcastle-Ottawa Scale and Physiotherapy Evidence Database assessed methodological quality of all studies.

RESULTS

Twenty-six observational and three intervention studies (n = 19-9,556) were included in the meta-analysis. Low vitamin D was associated with worse cognitive performance (OR = 1.24, CI = 1.14-1.35) and cognitive decline (OR = 1.26, CI = 1.09-1.23); with cross-sectional yielding a stronger effect compared to longitudinal studies. Vitamin D supplementation showed no significant benefit on cognition compared with control (SMD = 0.21, CI = -0.05 to 0.46).

CONCLUSION

Observational evidence demonstrates low vitamin D is related to poorer cognition; however, interventional studies are yet to show a clear benefit from vitamin D supplementation. From the evidence to date, there is likely a therapeutic age window relevant to the development of disease and therefore vitamin D therapy. Longitudinal lifespan studies are necessary to depict the optimal timing and duration in which repletion of vitamin D may protect against cognitive decline and dementia in aging, to better inform trials and practice towards a successful therapy.

Toxic effect of acrylamide on the development of hippocampal neurons of weaning rats

Although numerous studies have examined the neurotoxicity of acrylamide in adult animals, the effects on neuronal development in the embryonic and lactational periods are largely unknown. Thus, we examined the toxicity of acrylamide on neuronal development in the hippocampus of fetal rats during pregnancy. Sprague-Dawley rats were mated with male rats at a 1:1 ratio. Rats were administered 0, 5, 10 or 20 mg/kg acrylamide intragastrically from embryonic days 6–21. The gait scores were examined in pregnant rats in each group to analyze maternal toxicity. Eight weaning rats from each group were also euthanized on postnatal day 21 for follow-up studies. Nissl staining was used to observe histological change in the hippocampus. Immunohistochemistry was conducted to observe the condition of neurites, including dendrites and axons. Western blot assay was used to measure the expression levels of the specific nerve axon membrane protein, growth associated protein 43, and the presynaptic vesicle membrane specific protein, synaptophysin. The gait scores of gravid rats significantly increased, suggesting that acrylamide induced maternal motor dysfunction. The number of neurons, as well as expression of growth associated protein 43 and synaptophysin, was reduced with increasing acrylamide dose in postnatal day 21 weaning rats. These data suggest that acrylamide exerts dose-dependent toxic effects on the growth and development of hippocampal neurons of weaning rats.