Vitamin D3 and brain development

Calcitriol Modulates Hippocampal Axon Guidance Through Enhanced EfnA4-Mediated PI3K/AKT Signaling in an Autism Mouse Model

AIMS

Autism spectrum disorder (ASD) is a complex neurodevelopmental condition arising from the interplay of genetic predispositions and environmental influences. Recent studies have suggested that vitamin D (VitD) supplementation play a role in reducing the risk of ASD and alleviating some of its core symptoms. However, variations in individual responses to VitD due to biological heterogeneity have led to inconsistent clinical outcomes, and the precise molecular mechanisms through which VitD might exert its effects on ASD remain poorly understood.

METHODS

We investigated the effects of calcitriol, the biologically active form of VitD, on ASD-associated phenotypes in BTBR mice, a well-established autism model. Behavioral assessments were used to evaluate social and repetitive behaviors. Mechanistic insights were obtained through RNA sequencing, immunohistochemistry, biochemical assays, and stripe guidance assays.

RESULTS

Calcitriol supplementation significantly improved autism-like behaviors in BTBR mice, alleviating hippocampal hypoplasia and correcting axon guidance abnormalities. These effects were mediated by modulation of the EfnA4-PI3K signaling pathway in hippocampal neural progenitor cells and other brain regions, highlighting its role in neurodevelopmental processes.

CONCLUSION

Our findings demonstrate that calcitriol targets axon-guidance-related signaling pathways, providing a theoretical framework and potential clinical strategy for targeted ASD interventions.

Early disruptions in vitamin D receptor signaling induces persistent developmental behavior deficits in zebrafish larvae

A critical function of the nervous system is to rapidly process sensory information and initiate appropriate behavioral responses. Defects in sensory processing and behavior selection are commonly observed in neuro-psychiatric conditions including anxiety, autism (ASD), and schizophrenia. The etiology of sensory processing disorders remains equivocal; however, it is hypothesized that extrinsic environmental factors can play fundamental roles. In this study we examine the importance of vitamin D (1α, 25-dihydroxyvitamin D3) receptor signaling during early life stage development on sensory processing and neurobehavioral health outcomes. While vitamin D has traditionally been associated with mineral ion homeostasis, accumulating evidence suggests non-calcemic roles for vitamin D including early neurodevelopment. Here we demonstrate that systemic disruption of vitamin D receptor (VDR) signaling with a conditional dominant negative (dnVDR) transgenic zebrafish line results in specific visual and acoustic sensorimotor behavior defects. Induction of dnVDR between 24-72 hours post fertilization (hpf) results in modulation of visual motor response with demonstrate attenuation in acute activity and hypolocomotion across multiple swimming metrics when assayed at 6- and 28-days post fertilization (dpf). Disruption in VDR signaling additionally resulted in a strong and specific attenuation of the Long-Latency C-bends (LLC) within the acoustic startle response at 6 dpf while Short-Latency C-bends (SLC) were moderately impacted. Pre-pulse inhibition (PPI) was not impacted in young larvae however exhibited a significantly attenuated response at 28 dpf suggesting an inability to properly modulate their startle responses later in development and persistent effects of VDR modulation during early development. Overall, our data demonstrate that modulation of vitamin D signaling during critical windows of development irreversibly disrupts the development of neuronal circuitry associated with sensory processing behaviors which may have significant implications to neurobehavioral health outcomes.

Neurodevelopmental Outcomes in the Offspring of Women with Vitamin D Deficiency and Women Who Received Vitamin D Supplementation During Pregnancy

Vitamin D is an essential nutrient, involved in various biological processes including calcium homeostasis, bone health, immune function, and brain development. Vitamin D from the mother crosses the placenta during pregnancy, directly impacting the neurodevelopment of the fetus. Vitamin D insufficiency is a substantial global health problem, influencing almost 47.9% of individuals, with especially high predominance rates among pregnant women. Background/Objectives: Preclinical studies suggest that maternal vitamin D deficiency results in significant alterations in the development of the offspring's brain. Nonetheless, randomized clinical trials in humans have produced conflicting results on the beneficial effect of high-dose vitamin D supplementation during pregnancy on neurodevelopmental outcomes. This review aims to evaluate the association of maternal prenatal vitamin D levels and vitamin D supplementation during pregnancy with offspring neurodevelopment. Methods: This study thoroughly reviewed the literature and searched throughout PubMed, ScienceDirect, Cochrane Library, and Google Scholar, adhering to PRISMA guidelines. Studies assessing maternal vitamin D levels, supplementation, and offspring neurodevelopmental outcomes were included based on predefined eligibility criteria. Results: Among 9686 screened studies, only 20 met the inclusion criteria, representing 18,283 mother-child pairs. A small, non-significant trend suggested a positive association between higher maternal vitamin D levels and offspring cognitive, language, motor, and social-emotional development. The strongest associations were observed in cognitive performance and language acquisition, though inconsistencies emerged across studies. Cord blood vitamin D levels showed no consistent effects on neurodevelopment. Maternal vitamin D supplementation during pregnancy demonstrated no reliable benefits for offspring neurodevelopment, with results varying by study design and participant characteristics. Conclusions: Large-scale, multicenter randomized trials, with standardized neurodevelopmental assessments at multiple ages are needed to define the effects of vitamin D deficiency and supplementation during pregnancy on offspring neurodevelopmental outcomes. Future research should investigate the confounding factors contributing to inconsistencies, including supplementation protocols, genetic variations, and assessment methodologies. Clarifying these aspects will enhance the understanding of maternal vitamin D's role in fetal neurodevelopment and aid in refining prenatal supplementation guidelines.

Association Between Sun Exposure and Risk of Relapse in Pediatric-Onset Multiple Sclerosis

BACKGROUND AND OBJECTIVES

Low sun and ultraviolet radiation (UVR) exposures have been associated with increased risk of developing pediatric-onset multiple sclerosis (MS); however, their effect on disease course has not been well characterized. We primarily investigated whether there was an association between time spent in the sun in early childhood and risk of relapse in pediatric MS. We secondarily investigated the effect of sun exposure during more recent periods on risk of relapse.

METHODS

We conducted a multicenter cohort study of participants with pediatric-onset MS recruited from 18 pediatric MS clinics across the United States between November 1, 2011, and July 1, 2017. Relapses were identified prospectively after study enrollment; relapses preceding study enrollment were entered retrospectively. Time spent in the sun at various periods of life was measured using a detailed environmental questionnaire, and ambient UVR exposure was determined using zip codes. Multivariable Cox regression models were used to assess the association between time spent in the sun and UVR dose at specific periods of life and the risk of relapse. Models were adjusted for demographic, clinical, and sun exposure-related characteristics.

RESULTS

In our cohort of 334 children with MS, 206 (62%) experienced at least one relapse from disease onset to the end of the follow-up period. After adjustment, ≥30 minutes of daily sun exposure during the first summer of life was associated with a lower risk of relapse compared with <30 minutes (adjusted hazard ratio [aHR] 0.67, CI 0.48-0.92, p = 0.01). Greater time spent in the sun during the second trimester of pregnancy was also associated with reduced risk of relapse (aHR 0.68, CI 0.48-0.97, p = 0.04). UVR dose and time spent in the sun later in life were not significantly associated with relapse risk.

DISCUSSION

In this large cohort study of children with MS, greater early childhood and prenatal sun exposure time was associated with lower risk of relapse. Further investigation of sun exposure at other periods is needed to better characterize its impact on disease course and guide potential future interventions.

Vitamin D differentiates dopamine neurons in vitro, increasing neurite architecture, dopamine release and expression of relevant synaptic proteins

Epidemiological studies often link circulatory levels of 25 hydroxy vitamin D with an overwhelming variety of disorders. Of such studies, an increasing number are now linking blood 25 hydroxy vitamin D levels with certain brain disorders. Prominent amongst such disorders are schizophrenia and Parkinson's disease. The neurotransmitter dopamine is central to understanding the eitiology of both disorders with schizophrenia representing increased subcortical dopamine function and Parkinson's disease a disorder with the pathological hallmark of dopamine cellular pathology. Our group have established the epidemiology linking vitamin D deficiency in utero and later onset of schizophrenia. We have clarified many of the mechanisms behind how vitamin D effects dopamine neuron positioning, differentiation and survival. In this study we confirm vitamin D differentiates the dendritic architecture of dopamine neurons, that vitamin D may represent a requirement for drug-mediated dopamine release and that vitamin D may sculpt presynaptic proteins related to fast or phasic dopamine release.

Prenatal vitamin D levels and infant cognitive, motor, language and social-emotional development at 6 and 9 months of age

AIM

Vitamin D is involved in several processes related to the development of neuronal and non-neuronal cells. There is a possible link between maternal vitamin D status in pregnancy and delayed neurocognitive development in the offspring. The aim of the study was to explore the association of maternal and cord blood vitamin D levels with infants' neurodevelopment at 6 and 9 months of age.

METHODOLOGY

A cohort study was conducted in western Rajasthan, India. Maternal and cord blood samples were collected at the time of delivery. Serum 25(OH)-vitamin D levels were measured in both. Infant neurodevelopment was assessed at 6 and 9 months of age in six domains namely cognitive, receptive language, expressive language, fine motor, gross motor and social-emotional using the Bayley Scale of Infant Development- III (BSID-III).

RESULTS

A total of 175 mother-child pairs were enrolled. Among the mothers taking part in this study, 7.3% had deficient and 59.09% had insufficient levels of serum 25(OH) vitamin D during the third trimester of their pregnancy. Maternal and cord blood serum 25-OH vitamin D levels were 18.86 ± 8.53 ng/mL and 17.39 ± 8.87 ng/mL, respectively, and there was a significant correlation (r = 0.9778, p = 0.000) between levels of vitamin D. Based on the repeated measures ANOVA, post hoc Tukey's HSD test, maternal vitamin D levels had a significant relationship (p = 0.047) to the cognitive development of infants at 6 months of age. Furthermore, cord serum vitamin D levels showed a significant association (p = 0.023 and p = 0.010) with the social-emotional development of the infant at the age of 6 and 9 months.

CONCLUSION

Maternal and cord serum 25-OH vitamin D deficiency was significantly associated with the cognitive and social-emotional development of infants.

Association of serum total folate and serum vitamin D concentrations with W-shape in depressed older adults with cognitive dysfunction: A cross-sectional observational study

BACKGROUND

Depression and cognitive dysfunction are prevalent in the elderly population and have a serious impact on patients' quality of life and social functioning. Nutritional factors play a key role in the prevention and management of these disorders, particularly folate and vitamin D. The aim of this study was to elucidate the association between serum total folate and serum vitamin D concentrations and depressive symptoms and cognitive dysfunction in older adults.

METHODS

Using data from the National Health and Nutrition Examination Survey (NHANES) 2011-2014, 2042 participants aged 60 years and older were analyzed. Depressive symptoms were assessed by the Patient Health Questionnaire (PHQ-9) and cognitive function was assessed by the Consortium to Establish a Registry for Alzheimer's Disease (CERAD) Animal Fluency test and the Digit Symbol Substitution Test (DSST). Associations between serum total folate and vitamin D concentrations and depression with cognitive dysfunction were analyzed using multivariate logistic regression models, incorporating stratification and sensitivity analyses.

RESULTS

For every 1 nmol/L increase in serum vitamin D concentration, there was a 1 % reduction in the risk of depression in older adults (OR = 0.99 95 % CI 0.98-0.99). Serum total folate showed a significant W-shaped association with depression with cognitive dysfunction: when serum total folate concentration was below 33.00 nmol/L, the risk of depression was reduced by 7.6 % for every 1 nmol/L increase in its concentration (OR = 0.924 95 % CI 0.89-0.959); this association was not significant when the concentration was above 33.00 nmol/L (OR = 1.006 95 % CI 0.998-1.013).

CONCLUSIONS

Adequate levels of vitamin D and folate may help prevent and manage depression and cognitive dysfunction in older adults. The W-shaped association between serum total folate and these conditions suggests that folic acid supplementation could be effective within a specific range, warranting further exploration and validation through clinical studies.

Association between 25(OH) vitamin D and schizophrenia: shared genetic correlation, pleiotropy, and causality

Background

This study delves into the complex interplay between genetics, 25-hydroxyvitamin D (25OHD), and schizophrenia (SCZ). It leverages extensive sample data derived from Genome-Wide Association Studies (GWAS) to uncover genetic correlations.

Methods

Employing Linkage Disequilibrium Score Regression (LDSC) and S-LDSC, this study investigates genetic connections between 25OHD and SCZ. It examines Single Nucleotide Polymorphism (SNP) heritability in specific tissues and incorporates diverse immune cell datasets for genetic enrichment analysis. Local genetic correlations were analyzed using HESS software, and pleiotropy analysis identified shared genetic loci in brain tissues. Hyprcoloc analysis was used to explore shared genetic factors between 25OHD, immune cells, and SCZ, complemented by a bidirectional Mendelian Randomization (MR) to probe potential causal links.

Results

We identified a significant negative genetic correlation between 25OHD levels and SCZ. PLACO analysis revealed 35 pleiotropic loci with strong enrichment in brain regions, particularly the cerebellum, frontal cortex, and hippocampus. Eight loci (1p34.2, 2p23.3, 3p21.1, 5q31.2, 12q23.2, 14q32.33, 16p13.3, and 16q24.3) exhibited strong colocalization, highlighting potential drug targets. Gene and tissue enrichment analyses emphasized neurological and immune-related mechanisms, including hyaluronan metabolism. Bidirectional MR analysis supported a causal effect of SCZ on 25OHD levels.

Conclusion

Our study identifies NEK4 as a potential therapeutic target and highlights the involvement of hyaluronan metabolism in the genetic association between 25OHD and SCZ. These findings provide valuable insights into shared genetic pathways, immune-related connections, and causal interactions in the context of SCZ.

Neuroplasticity-related effects of vitamin D relevant to its neuroprotective effects: A narrative review

The pathophysiology of a wide range of central nervous system (CNS) disorders, such as neurodegenerative and psychiatric diseases, has been associated with impairment of neurogenic and synaptogenic processes. Therefore, pharmacological and/or nutritional strategies based on the stimulation and/or restoration of these processes may have beneficial effects against diseases in which these processes are impaired. In this context, vitamin D has emerged as a promising neuroprotective compound. Due to its pleiotropic properties, it can interact with multiple molecular targets and thereby affect different cell types, including neurons and glial cells. This neurosteroid contributes to CNS homeostasis by non-genomic and genomic mechanisms through its interaction with vitamin D receptors (VDRs). Among several properties of this vitamin, its role in neuronal proliferation and differentiation as well as in synaptic plasticity has received attention. Considering this background, this narrative review aims to highlight the neuroplasticity-related mechanisms of vitamin D that may be associated with its neuroprotective effects.

Vitamins, minerals and their maternal levels' role in brain development: An updated literature-review

One's neurobehavioural and mental health are built during the exact and complex process of brain development. It is thought that fetal development is where neuropsychiatric disorders first emerged. Behavioural patterns can change as a result of neuropsychiatric illnesses. The incidence is rising quickly; nevertheless, providing exceptional care remains a significant challenge for families and healthcare systems. It has been demonstrated that one of the main factors causing the transmission of these diseases is maternal exposure. Through physiologic pathways, maternal health and intrauterine exposures can affect brain development. Our attention has been focused on epigenetic factors, particularly in the gestational environment, which may be responsible for human neurodegenerative diseases since our main mental development occurs during the nine months of intrauterine life. After thoroughly searching numerous databases, this study examined the effect of fat-soluble vitamins, water-soluble vitamins, and minerals and their maternal-level effect on brain development.

Vitamin D Deficiency Does Not Affect Cognition and Neurogenesis in Adult C57Bl/6 Mice

Vitamin D deficiency is a global problem. Vitamin D, the vitamin D receptor, and its enzymes are found throughout neuronal, ependymal, and glial cells in the brain and are implicated in certain processes and mechanisms in the brain. To investigate the processes affected by vitamin D deficiency in adults, we studied vitamin D deficient, control, and supplemented diets over 6 weeks in male and female C57Bl/6 mice. The effect of the vitamin D diets on proliferation in the neurogenic niches, changes in glial cells, as well as on memory, locomotion, and anxiety-like behavior, was investigated. Six weeks on a deficient diet was adequate time to reach deficiency. However, vitamin D deficiency and supplementation did not affect proliferation, neurogenesis, or astrocyte changes, and this was reflected on behavioral measures. Supplementation only affected microglia in the dentate gyrus of female mice. Indicating that vitamin D deficiency and supplementation do not affect these processes over a 6-week period.

Tremendous Fidelity of Vitamin D3 in Age-related Neurological Disorders

Vitamin D3 (VD) is a secosteroid hormone and shows a pleiotropic effect in brain-related disorders where it regulates redox imbalance, inflammation, apoptosis, energy production, and growth factor synthesis. Vitamin D3's active metabolic form, 1,25-dihydroxy Vitamin D3 (1,25(OH)2D3 or calcitriol), is a known regulator of several genes involved in neuroplasticity, neuroprotection, neurotropism, and neuroinflammation. Multiple studies suggest that VD deficiency can be proposed as a risk factor for the development of several age-related neurological disorders. The evidence for low serum levels of 25-hydroxy Vitamin D3 (25(OH)D3 or calcidiol), the major circulating form of VD, is associated with an increased risk of Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD), dementia, and cognitive impairment. Despite decades of evidence on low VD association with neurological disorders, the precise molecular mechanism behind its beneficial effect remains controversial. Here, we will be delving into the neurobiological importance of VD and discuss its benefits in different neuropsychiatric disorders. The focus will be on AD, PD, and HD as they share some common clinical, pathological, and epidemiological features. The central focus will be on the different attributes of VD in the aspect of its anti-oxidative, anti-inflammatory, anti-apoptotic, anti-cholinesterase activity, and psychotropic effect in different neurodegenerative diseases.

Correlation analysis of 25(OH)D with cognitive function in epilepsy patients: A cross-sectional study

OBJECTIVE

To analyze the correlation between the level of 25(OH)D in peripheral blood and cognitive function in patients with epilepsy, and to find the biomarkers of epilepsy complicated with cognitive dysfunction.

METHODS

68 patients with epilepsy and 30 healthy subjects were included in this study. The 25(OH)D level in peripheral blood of all subjects was detected and the score of the Montreal Cognitive Assessment Scale was performed. The patients with epilepsy were divided into a cognitively normal group (36 cases) and a cognitively impaired group (32 cases) according to the scale score. The inter-group scale score and 25(OH)D level were compared, and the correlation was analyzed.

RESULTS

The levels of 25(OH)D and MOCA in epileptic group were significantly lower than those in healthy control group. The 25(OH)D and MOCA of the cognitively impaired group were significantly lower than those of the cognitively normal group. Logistic regression analysis indicated that serum 25(OH)D level was an independent risk factor for epilepsy combined with cognitive impairment (OR = 0.704, P = 0.014). The area under ROC curve of serum 25(OH)D for diagnosis of epilepsy combined with cognitive impairment was 0.924 (95 %CI 0.866,0.981), the critical value was 34.50 nmol/L, the sensitivity was 0.778, and the specificity was 0.906.

CONCLUSION

Decreased levels of vitamin D are associated with cognitive impairment associated with epilepsy, and it may be a biomarker for early screening of cognitive impairment.

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.

The metabolic role of vitamin D in children's neurodevelopment: a network study

Neurodevelopmental disorders are rapidly increasing in prevalence and have been linked to various environmental risk factors. Mounting evidence suggests a potential role of vitamin D in child neurodevelopment, though the causal mechanisms remain largely unknown. Here, we investigate how vitamin D deficiency affects children's communication development, particularly in relation to Autism Spectrum Disorder (ASD). We do so by developing an integrative network approach that combines metabolomic profiles, clinical traits, and neurodevelopmental data from a pediatric cohort. Our results show that low levels of vitamin D are associated with changes in the metabolic networks of tryptophan, linoleic, and fatty acid metabolism. These changes correlate with distinct ASD-related phenotypes, including delayed communication skills and respiratory dysfunctions. Additionally, our analysis suggests the kynurenine and serotonin sub-pathways may mediate the effect of vitamin D on early life communication development. Altogether, our findings provide metabolome-wide insights into the potential of vitamin D as a therapeutic option for ASD and other communication disorders.

Vitamin D in Central Nervous System: Implications for Neurological Disorders

Vitamin D, obtained from diet or synthesized internally as cholecalciferol and ergocalciferol, influences bodily functions through its most active metabolite and the vitamin D receptor. Recent research has uncovered multiple roles for vitamin D in the central nervous system, impacting neural development and maturation, regulating the dopaminergic system, and controlling the synthesis of neural growth factors. This review thoroughly examines these connections and investigates the consequences of vitamin D deficiency in neurological disorders, particularly neurodegenerative diseases. The potential benefits of vitamin D supplementation in alleviating symptoms of these diseases are evaluated alongside a discussion of the controversial findings from previous intervention studies. The importance of interpreting these results cautiously is emphasised. Furthermore, the article proposes that additional randomised and well-designed trials are essential for gaining a deeper understanding of the potential therapeutic advantages of vitamin D supplementation for neurological disorders. Ultimately, this review highlights the critical role of vitamin D in neurological well-being and highlights the need for further research to enhance our understanding of its function in the brain.

Processed foods and diet quality in pregnancy may affect child neurodevelopment disorders: a narrative review

OBJECTIVE

To review the evidence on the association between maternal exposure to ultra-processed food (UPF) categories, UPF diet items, and overall diet quality, as assessed by recognized dietary indices, and neurodevelopmental outcomes in offspring.

METHODS

PubMed, MEDLINE, EMBASE, Scopus, Ovid, and Scholar databases were searched for original articles on female gestational exposure to UPF categories, individual elements of the UPF diet, or indices of diet quality, in relation to outcomes regarding their offspring's neurocognitive development, according to neuropsychometric and behavioral scales, anthropometric/psychomotor indices, and symptoms/diagnosis of neurodevelopmental disorders (NDDs).

RESULTS

Fourteen articles were selected and underwent the quantitative analysis. Six of these examined diet quality, and eight exposure to UPF categories or specific UPF foods. The maternal population was adult (18+). Child cognitive development was negatively impacted by a diet featuring many processed foods, saturated fats, and sugars. Conversely, a Med-diet led to better neurodevelopment, particularly verbal intelligence and executive functions, in middle childhood.

DISCUSSION

A maternal diet with many UPFs, saturated fats, and total sugars (especially those added or hidden in packaged carbonated beverages) can adversely affect a child's cognitive development. Knowledge needs to be further extended and managed from a prevention perspective in light of the well-known negative effects of UPFs on human health in all age groups.

The role of vitamin D in depression and anxiety disorders: a review of the literature

BACKGROUND

Prevalence of mental health disorders continue to increase worldwide. Over the past decades, suboptimal vitamin D (VD) levels and gut dysbiosis have been associated with neurological dysfunction and psychiatric disorders.

METHODS

In this review, we examined the available literature on VD and mental health disorders, particularly depression and anxiety, in both clinical and pre-clinical studies.

RESULTS

Our extensive review failed to find a link between VD deficiency, depression, and anxiety-related behavior in preclinical animal models. However, strong evidence suggests that VD supplementation may alleviate symptoms in chronically stressed rodents, with some promising evidence from clinical studies. Further, fecal microbiota transplantations suggest a potential role of gut microbiota in neuropsychiatric disorders, although the underlying mechanisms remain to be fully elucidated. It has been postulated that serotonin, primarily produced by gut bacteria, may be a crucial factor. Hence, whether VD has the ability to impact gut microbiota and modulate serotonin synthesis warrants further investigation.

CONCLUSIONS

Taken together, literature has suggested that VD may serve as a key regulator in the gut-brain axis to modulate gut microbiota and alleviate symptoms of depression and anxiety. The inconsistent results of VD supplementation in clinical studies, particularly among VD deficient participants, suggests that current intake recommendations may need to be re-evaluated for individuals at-risk (i.e. prior to diagnosis) of developing depression and/or anxiety.

Vitamin D and Its Role on the Fatigue Mitigation: A Narrative Review

Vitamin D has historically been associated with bone metabolism. However, over the years, a growing body of evidence has emerged indicating its involvement in various physiological processes that may influence the onset of numerous pathologies (cardiovascular and neurodegenerative diseases, rheumatological diseases, fertility, cancer, diabetes, or a condition of fatigue). This narrative review investigates the current knowledge of the pathophysiological mechanisms underlying fatigue and the ways in which vitamin D is implicated in these processes. Scientific studies in the databases of PubMed, Scopus, and Web of Science were reviewed with a focus on factors that play a role in the genesis of fatigue, where the influence of vitamin D has been clearly demonstrated. The pathogenic factors of fatigue influenced by vitamin D are related to biochemical factors connected to oxidative stress and inflammatory cytokines. A role in the control of the neurotransmitters dopamine and serotonin has also been demonstrated: an imbalance in the relationship between these two neurotransmitters is linked to the genesis of fatigue. Furthermore, vitamin D is implicated in the control of voltage-gated calcium and chloride channels. Although it has been demonstrated that hypovitaminosis D is associated with numerous pathological conditions, current data on the outcomes of correcting hypovitaminosis D are conflicting. This suggests that, despite the significant involvement of vitamin D in regulating mechanisms governing fatigue, other factors could also play a role.

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.

Effects of 1,25-Vitamin D3 and 24,25-Vitamin D3 on Corneal Nerve Regeneration in Diabetic Mice

Corneal nerve homeostasis is essential for the functional integrity of the ocular surface. Vitamin D deficiency (VDD) and vitamin D receptor knockout (VDR KO) have been found to reduce corneal nerve density in diabetic mice. This is the first study to comprehensively examine the influence of vitamin D on nerve regeneration following corneal epithelial injury in diabetic mice. Corneal nerve regeneration was significantly retarded by diabetes, VDR KO, and VDD, and it was accelerated following topical 1,25 Vit D and 24,25 Vit D administration. Furthermore, topical 1,25 Vit D and 24,25 Vit D increased nerve growth factor, glial cell line-derived neurotropic factor, and neurotropin-3 protein expression, and it increased secretion of GDNF protein from human corneal epithelial cells. CD45+ cells and macrophage numbers were significantly decreased, and vitamin D increased CD45+ cell and macrophage recruitment in these wounded diabetic mouse corneas. The accelerated nerve regeneration observed in these corneas following topical 1,25 Vit D and 24,25 Vit D administration may be related to the vitamin D-stimulated expression, secretion of neurotrophic factors, and recruitment of immune cells.

Maternal vitamin D status and attention deficit hyperactivity disorder (ADHD), an under diagnosed risk factor; A review

Vitamin D is important to mediate several brain processes such as proliferation, apoptosis, and neurotransmission in early stages of life. Vitamin D deficiency during critical periods of development can lead to persistent brain alterations. Vitamin D homeostasis during pregnancy is affected by two factors which includes an increase in mother’s calcitriol levels and an increase in mother’s Vitamin D Binding protein concentrations. Attention deficient hyperactivity disorder (ADHD) is an outcome of a complicated interaction between genetic, environmental, and developmental traits, and genetic factors cover about 80% of the cases. The efficiency of the immune system can be altered by a deficiency of Vitamin D in maternal body and maternal stress during gestation such as perinatal depression. Studies have proved that during gestation if there is a deficiency of vitamin D in maternal body, it can influence the brain development of the fetus and can also alter the synthesis of the brain-derived neurotropic factor. The current manuscript has been compiled to elaborate different factors which are associated with ADHD particularly focusing on the relationship of vitamin D deficiency in mothers. References material was selected from NCBI (PUBMED), Science direct, Google scholar, Publons etc. Using the terms ADHD, Vitamin D and Maternal nutritional status. Although, controversial relationship was found between the deficiency of Vitamin D level in pregnant women and development of ADHD in children but more controlled trials are required for future direction as well as to rule out other associated causes.

Genome-wide Association Analysis of Schizophrenia and Vitamin D Levels Shows Shared Genetic Architecture and Identifies Novel Risk Loci

Low vitamin D (vitD) levels have been consistently reported in schizophrenia (SCZ) suggesting a role in the etiopathology. However, little is known about the role of underlying shared genetic mechanisms. We applied a conditional/conjunctional false discovery rate approach (FDR) on large, nonoverlapping genome-wide association studies for SCZ (N cases = 53 386, N controls = 77 258) and vitD serum concentration (N = 417 580) to evaluate shared common genetic variants. The identified genomic loci were characterized using functional analyses and biological repositories. We observed cross-trait SNP enrichment in SCZ conditioned on vitD and vice versa, demonstrating shared genetic architecture. Applying the conjunctional FDR approach, we identified 72 loci jointly associated with SCZ and vitD at conjunctional FDR < 0.05. Among the 72 shared loci, 40 loci have not previously been reported for vitD, and 9 were novel for SCZ. Further, 64% had discordant effects on SCZ-risk and vitD levels. A mixture of shared variants with concordant and discordant effects with a predominance of discordant effects was in line with weak negative genetic correlation (rg = -0.085). Our results displayed shared genetic architecture between SCZ and vitD with mixed effect directions, suggesting overlapping biological pathways. Shared genetic variants with complex overlapping mechanisms may contribute to the coexistence of SCZ and vitD deficiency and influence the clinical picture.

Vitamin D: A potent regulator of dopaminergic neuron differentiation and function

Vitamin D has been identified as a key factor in dopaminergic neurogenesis and differentiation. Consequently, developmental vitamin D (DVD) deficiency has been linked to disorders of abnormal dopamine signalling with a neurodevelopmental basis such as schizophrenia. Here we provide further evidence of vitamin D's role as a mediator of dopaminergic development by showing that it increases neurite outgrowth, neurite branching, presynaptic protein re-distribution, dopamine production and functional release in various in vitro models of developing dopaminergic cells including SH-SY5Y cells, primary mesencephalic cultures and mesencephalic/striatal explant co-cultures. This study continues to establish vitamin D as an important differentiation agent for developing dopamine neurons, and now for the first time shows chronic exposure to the active vitamin D hormone increases the capacity of developing neurons to release dopamine. This study also has implications for understanding mechanisms behind the link between DVD deficiency and schizophrenia.

Microglia and Brain Disorders: The Role of Vitamin D and Its Receptor

Accounting for 5-20% of the total glial cells present in the adult brain, microglia are involved in several functions: maintenance of the neural environment, response to injury and repair, immunesurveillance, cytokine secretion, regulation of phagocytosis, synaptic pruning, and sculpting postnatal neural circuits. Microglia contribute to some neurodevelopmental disorders, such as Nasu-Hakola disease (NHD), Tourette syndrome (TS), autism spectrum disorder (ASD), and schizophrenia. Moreover, microglial involvement in neurodegenerative diseases, such as Alzheimer's (AD) and Parkinson's (PD) diseases, has also been well established. During the last two decades, epidemiological and research studies have demonstrated the involvement of vitamin D3 (VD3) in the brain's pathophysiology. VD3 is a fat-soluble metabolite that is required for the proper regulation of many of the body's systems, as well as for normal human growth and development, and shows neurotrophic and neuroprotective actions and influences on neurotransmission and synaptic plasticity, playing a role in various neurological diseases. In order to better understand the exact mechanisms behind the diverse actions of VD3 in the brain, a large number of studies have been performed on isolated cells or tissues of the central nervous system (CNS). Here, we discuss the involvement of VD3 and microglia on neurodegeneration- and aging-related diseases.

Neurological Symptoms That May Represent a Warning in Terms of Diagnosis and Treatment in a Group of Children and Adolescents with Vitamin D Deficiency

AIM

This research was intended to evaluate the clinical and laboratory findings of children presenting to our pediatric neurology clinic with symptoms potentially linked to vitamin D deficiency and with low vitamin D levels and the distribution of those findings by sex, age groups, and vitamin D levels.

METHODS

This retrospective study involved patients presenting to our clinic with symptoms potentially associated with vitamin D deficiency and low serum concentrations of 25 OH vitamin D (25 OH D) (<75 nmol/L, 30 µg/mL). Patients' movement disorders and central nervous system-related symptoms at the time of presentation and serum 25 OH D, calcium (Ca), phosphorus (P), and magnesium (Mg) levels were recorded and evaluated in terms of age, sex, and vitamin D levels.

RESULTS

Eight hundred twenty-two cases of vitamin D deficiency were included in the study, 50.2% (n = 413) boys and 49.8% (n = 409) girls. Although cases of vitamin D deficiency were present across all the age groups between 1 and 18, they were most common in the 5-14 age range (n = 372, 45.3%). Movement disorders were observed in 14.6% (n = 120) of our cases, and neurological findings associated with the central nervous system were observed in 52.6% (n = 432). The most common accompanying movement in our cases was difficulty remaining in balance (n = 42, 35%), while the most frequent accompanying central nervous system finding was vertigo (n = 99, 22.92%). Other movement disorders encountered included limb shaking (n = 32, 26.7%), abnormal posture (n = 20, 16.67%), easy falling (n = 16, 13.33%), body rigidity (n = 15, 12.5%), and hand clenching (n = 5, 4.17%). Other frequently encountered neurological findings were headache (n = 88, 20.37%), epileptic seizures (n = 83, 19.21%), fainting (n = 58, 13.43%), developmental delay (n = 41, 9.49%), febrile seizures (n = 33, 7.64%), and numbness in the fingers (n = 20, 4.63%). Other neurological findings were sleep disorders (n = 10, 2.31%), nightmares (n = 8, 1.85%), pain in the extremities (n = 7, 1.62%), and sweating and frailty (n = 4, 0.93% for both). Ca, P, and Mg levels were lower in cases with vitamin D levels < 12 µg/mL. The prevalences of both movement disorders and central nervous system findings varied according to age groups, sex, and vitamin D levels.

CONCLUSIONS

Our study results show that vitamin D deficiency can present with different neurological findings and that these may vary according to age group, sex, and vitamin D levels. Clinicians must take particular care in pediatric cases with neurological findings in terms of the early diagnosis and treatment of vitamin D deficiency.

The Synaptic and Circuit Functions of Vitamin D in Neurodevelopment Disorders

Vitamin D deficiency/insufficiency is a public health issue around the world. According to epidemiological studies, low vitamin D levels have been associated with an increased risk of some neurodevelopmental disorders, including autism spectrum disorder (ASD) and attention-deficit hyperactivity disorder (ADHD). Animal models reveal that vitamin D has a variety of impacts on the synapses and circuits in the brain. A lack of vitamin D affects the expression of synaptic proteins, as well as the synthesis and metabolism of various neurotransmitters. Depending on where vitamin D receptors (VDRs) are expressed, vitamin D may also regulate certain neuronal circuits through the endocannabinoid signaling, mTOR pathway and oxytocin signaling. While inconsistently, some data suggest that vitamin D supplementation may be able to reduce the core symptoms of ASD and ADHD. This review emphasizes vitamin D's role in the synaptic and circuit mechanisms of neurodevelopmental disorders including ASD and ADHD. Future application of vitamin D in these disorders will depend on both basic research and clinical studies, in order to make the transition from the bench to the bedside.

Developmental vitamin D-deficiency produces autism-relevant behaviours and gut-health associated alterations in a rat model

Developmental vitamin D (DVD)-deficiency is an epidemiologically established risk factor for autism. Emerging studies also highlight the involvement of gut microbiome/gut physiology in autism. The current study aims to examine the effect of DVD-deficiency on a broad range of autism-relevant behavioural phenotypes and gut health. Vitamin D deficient rat dams exhibited altered maternal care, DVD-deficient pups showed increased ultrasonic vocalizations and as adolescents, social behaviour impairments and increased repetitive self-grooming behaviour. There were significant impacts of DVD-deficiency on gut health demonstrated by alterations to the microbiome, decreased villi length and increased ileal propionate levels. Overall, our animal model of this epidemiologically validated risk exposure for autism shows an expanded range of autism-related behavioural phenotypes and now alterations in gut microbiome that correlate with social behavioural deficits raising the possibility that DVD-deficiency induced ASD-like behaviours are due to alterations in gut health.

Greater Gestational Vitamin D Status is Associated with Reduced Childhood Behavioral Problems in the Environmental Influences on Child Health Outcomes Program

BACKGROUND

Vitamin D deficiency is common in pregnancy. Vitamin D plays an important role in the developing brain, and deficiency may impair childhood behavioral development.

OBJECTIVES

This study examined the relationship between gestational 25(OH)D concentrations and childhood behavior in the Environmental influences on Child Health Outcomes (ECHO) Program.

METHODS

Mother-child dyads from ECHO cohorts with data available on prenatal (first trimester through delivery) or cord blood 25(OH)D and childhood behavioral outcomes were included. Behavior was assessed using the Strengths and Difficulties Questionnaire or the Child Behavior Checklist, and data were harmonized using a crosswalk conversion. Linear mixed-effects models examined associations of 25(OH)D with total, internalizing, and externalizing problem scores while adjusting for important confounders, including age, sex, and socioeconomic and lifestyle factors. The effect modification by maternal race was also assessed.

RESULTS

Early (1.5-5 y) and middle childhood (6-13 y) outcomes were examined in 1688 and 1480 dyads, respectively. Approximately 45% were vitamin D deficient [25(OH)D < 20 ng/mL], with Black women overrepresented in this group. In fully adjusted models, 25(OH)D concentrations in prenatal or cord blood were negatively associated with externalizing behavior T-scores in middle childhood [-0.73 (95% CI: -1.36, -0.10) per 10 ng/mL increase in gestational 25(OH)D]. We found no evidence of effect modification by race. In a sensitivity analysis restricted to those with 25(OH)D assessed in prenatal maternal samples, 25(OH)D was negatively associated with externalizing and total behavioral problems in early childhood.

CONCLUSIONS

This study confirmed a high prevalence of vitamin D deficiency in pregnancy, particularly among Black women, and revealed evidence of an association between lower gestational 25(OH)D and childhood behavioral problems. Associations were more apparent in analyses restricted to prenatal rather than cord blood samples. Interventions to correct vitamin D deficiency during pregnancy should be explored as a strategy to improve childhood behavioral outcomes.

Neuroinflammation in Alzheimer's disease: potential beneficial effects of vitamin D

Alzheimer's disease (AD) is the most common cause of dementia. In recent years, several studies have robustly shown that neuroinflammation plays a crucial role in the pathophysiology of this disease. The co-localization of amyloid-β plaques near activated glial cells and the increased levels of inflammatory cytokines in AD patients indicate the involvement of the neuroinflammatory process in AD progression. Considering that pharmacological treatment remains a challenge for the management of this disease, compounds with anti-inflammatory and antioxidant properties are promising therapeutic strategies. In this context, vitamin D has gained attention in the last few years due to its neuroprotective property and the high prevalence of vitamin D deficiency in the population. Herein, in this narrative review we present the possible contribution of the antioxidant and anti-inflammatory properties of vitamin D for its neuroprotective effects, and the clinical and preclinical data dealing with the effects of vitamin D in AD, focusing mainly on the neuroinflammatory process.

Does vitamin D level associate with pregnancy outcomes in Chinese women undergoing in vitro fertilization/intracytoplasmic sperm injection-embryo transfer? A retrospective cohort study

AIM

To explore the relationship between serum 25(OH)D level and pregnancy outcomes (clinical pregnancy rate [CPR] and live birth rate [LBR]) in Chinese women receiving in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI)-embryo transfer (ET) (IVF/ICSI-ET).

METHODS

A total of 612 patients included in the study were divided into four cohorts according to serum 25(OH)D with the threshold of 20 ng/ml, 25 ng/ml, 30 ng/ml, and retrospectively analyzed.

RESULTS

None of the baseline characteristics of participants was significantly different in the four cohorts except gravid status. The trend of 25(OH)D concentration was positively correlated with CPR and LBR. The younger (age: p < 0.001 both in CPR and LBR) women with primary infertility (infertility type: p = 0.004 in LBR) were more likely to get a better pregnancy outcome under the same 25(OH)D concentration stages. As shown on heatmap plots, CPR, and LBR were significantly increased for 25(OH)D concentrations above 30.00 ng/ml and women younger than 30 years old. The adjusted binary logistic regression and restricted cubic spline (RCS) showed that there existed a nonlinear positive correlation between 25(OH)D concentration and pregnancy outcome (CPR and LBR) (P_nonlinear  < 0.001, respectively). The women with a sufficient 25(OH)D concentration (30 ng/ml) had 1.07 (clinical pregnancy) and 1.05 (live birth) times higher successful birth outcomes compared to women with an insufficient 25(OH)D concentration (25 ng/ml). (OR_{25 ng/ml, ref = 30 ng/ml} [95% CI] = 0.935 [0.932-0.938] and 0.947 [0.945-0.950], p < 0.001, respectively).

CONCLUSION

In Chinese women receiving IVF/ICSI-ET, the serum level of 25(OH)D demonstrated a nonlinear positive correlation with pregnancy outcomes (CPR and LBR), with stronger correlations above 25 ng/ml and worse yields below 30 ng/ml. However, it could not yet be considered different in distinct ages.

Developmental Manipulation-Induced Changes in Cognitive Functioning

Schizophrenia is a complex neurodevelopmental disorder with as-yet no identified cause. The use of animals has been critical to teasing apart the potential individual and intersecting roles of genetic and environmental risk factors in the development of schizophrenia. One way to recreate in animals the cognitive impairments seen in people with schizophrenia is to disrupt the prenatal or neonatal environment of laboratory rodent offspring. This approach can result in congruent perturbations in brain physiology, learning, memory, attention, and sensorimotor domains. Experimental designs utilizing such animal models have led to a greatly improved understanding of the biological mechanisms that could underlie the etiology and symptomology of schizophrenia, although there is still more to be discovered. The implementation of the Research and Domain Criterion (RDoC) has been critical in taking a more comprehensive approach to determining neural mechanisms underlying abnormal behavior in people with schizophrenia through its transdiagnostic approach toward targeting mechanisms rather than focusing on symptoms. Here, we describe several neurodevelopmental animal models of schizophrenia using an RDoC perspective approach. The implementation of animal models, combined with an RDoC framework, will bolster schizophrenia research leading to more targeted and likely effective therapeutic interventions resulting in better patient outcomes.

Understanding the role of "sunshine vitamin D" in Parkinson's disease: A review

Next to Alzheimer's disease, Parkinson's disease constitutes the second most widespread neurological disorder, primarily affecting the older population. Its symptoms are noticeable with advancing age including tremors, postural imbalance, and slow movements, and over time, these symptoms get aggravated, progressing to osteoporosis, osteopenia, and risk of fractures. These symptoms correlate to low bone density and hence weakened bones; thus, vitamin D proves to be an intricate component of the pathogenesis of the disease. Moreover, lower serum concentrations of vitamin D have been found in diseased subjects. Supplementation with vitamin D can retard the aggravation of non-motor as well as motor symptoms of Parkinson's disease that include cognitive improvement along with the decline in risk of fractures. Also, vitamin D is extremely crucial for brain functioning, targeting dopaminergic neurons, and almost the entire functioning of the brain is affected. However, further exploration is required to determine the toxic dose of vitamin D in Parkinson's subjects. This "sunshine vitamin" surely can be a ray of sunshine for neurologically diseased subjects.

Is vitamin D supplementation of potential benefit for community-living people with Alzheimer's disease?

BACKGROUND

Vitamin D is associated not only with effects on calcium and bone metabolisms but also with many chronic diseases. Low vitamin D levels in patients with Alzheimer's disease have been widely reported in the literature.

AIM

The purpose of this study was to critically review the potential benefit of vitamin D supplementation in individuals with Alzheimer's disease living in the community.

METHODS

A systematic literature search was conducted in PubMed, CINAHL, EMBASE and the Cochrane Library for papers published 2011-2018.

RESULTS

Seven papers were selected, consisting of one clinical trial, five cohort studies and one systematic review. Studies showed an association only between vitamin D deficiency and lower attention in older people. None of the reviewed studies provided evidence of a positive impact of vitamin D supplementation on cognitive function in older people with Alzheimer's disease.

CONCLUSION

There was no evidence that vitamin D supplementation has a direct benefit for Alzheimer's disease. The review synthesised the existing body of knowledge and concluded that optimum levels of vitamin D (neither too low nor too high) do appear to have positive effects on patient outcomes and quality of life. It is still unclear why vitamin D intake is inadequate as people age. Further research is needed to clarify vitamin-D-related aspects of Alzheimer's disease.

Therapeutic and mechanistic intervention of vitamin D in neuropsychiatric disorders

Vitamin D deficiency is believed to affect between 35 and 55% of the world's population, making it a hidden pandemic. In addition to its role in bone and calcium homeostasis, vitamin D has also been linked in preclinical and clinical research to brain function. These outcomes have also been used for a variety of neuropsychiatric and neurodevelopmental problems. Nevertheless, these individuals are more prone to develop signs of cognitive decline. This review will emphasize the association between vitamin D and neuropsychiatric illnesses such as autism, schizophrenia, depression, and Attention Deficit Hyperactivity Disorder (ADHD). While numerous research show vitamin D's essential role in cognitive function in neuropsychiatric illnesses, it is too early to propose its effect on cognitive symptoms with certainty. It is necessary to conduct additional research into the associations between vitamin D deficiency and cognitive abnormalities, particularly those found in autism, schizophrenia, depression, and ADHD, to develop initiatives that address the pressing need for novel and effective preventative therapeutic strategies.

Vitamin D and the Central Nervous System: Causative and Preventative Mechanisms in Brain Disorders

Twenty of the last one hundred years of vitamin D research have involved investigations of the brain as a target organ for this hormone. Our group was one of the first to investigate brain outcomes resulting from primarily restricting dietary vitamin D during brain development. With the advent of new molecular and neurochemical techniques in neuroscience, there has been increasing interest in the potential neuroprotective actions of vitamin D in response to a variety of adverse exposures and how this hormone could affect brain development and function. Rather than provide an exhaustive summary of this data and a listing of neurological or psychiatric conditions that vitamin D deficiency has been associated with, here, we provide an update on the actions of this vitamin in the brain and cellular processes vitamin D may be targeting in psychiatry and neurology.

Vitamin D suppresses ferroptosis and protects against neonatal hypoxic-ischemic encephalopathy by activating the Nrf2/HO-1 pathway

BACKGROUND

Hypoxic-ischemic encephalopathy (HIE) is a major cause of neonatal death, and vitamin D (VD) is a neuroprotection nutrition whose deficiency is associated with its risk. However, the mechanism of VD involved in neonatal HIE is not well known.

METHODS

In this experiment a hypoxic-ischemic brain damage (HIBD) model was established by using the Rice-Vannucci method, rats were intraperitoneally injected with 0.1 µg/kg VD every day for two weeks. The brain damage and mitochondria injury were examined by hematoxylin-eosin (HE) staining and transmission electron microscope (TEM), respectively. The oxidation response and inflammatory factors were determined by enzyme-linked immunosorbent assay (ELISA), and the cell viability was determined by Cell Counting Kit-8 (CCK-8). mRNA and protein expression were detected by quantitative real real-time PCR (qRT-PCR), Western blot, and immunofluorescence.

RESULTS

The results showed VD effectively ameliorated brain histologic damage and mitochondria injury induced by hypoxic ischemia (HI). VD elevated the expression of Nrf2 and HO-1, which resulted in increased levels of GPX4, superoxide dismutase (SOD), and glutathione (GSH) and reduced content of malondialdehyde (MDA) and reactive oxygen species (ROS), resulting in decreased ferroptosis in HI-treated rats. Moreover, VD reduced the secretion of inflammatory factors, tumor necrosis factor-α (TNF-α), interleukin (IL)-6, and IL-1β.

CONCLUSIONS

VD suppresses ferroptosis through activation of the Nrf2/HO-1 signaling pathway and exerts a protective role in neonatal HIE.

Developmental exposure to vitamin D deficiency and subsequent risk of schizophrenia

Over the last half century, a body of convergent evidence has accumulated linking disruption of early brain development with an increased risk of mental disorders, including schizophrenia. The orderly cascade of brain development may be disrupted by exposure to suboptimal concentrations of a range of biological substrates and micronutrients. We hypothesized that those exposed to vitamin D deficiency during early life, have an increased risk of neurodevelopmental disorders, including schizophrenia. The hypothesis was based on the link between an increased risk of schizophrenia in (a) those born in winter and spring, when vitamin D deficiency is more prevalent, and (b) the offspring of dark-skinned migrants living in cold climates, who have a markedly increased risk of vitamin D deficiency. In this review, we summarize evidence from analytic epidemiology related to this hypothesis. Two case-control studies based on Danish neonatal dried blood spots have found that neonatal vitamin deficiency is associated with an increased risk of schizophrenia. However, recent genetic analyses have also suggested that common variants linked to schizophrenia may lead to lower vitamin D concentrations (possibly mediated via reduced outdoor activity). We summarize limitations of the current evidence and outline suggestions that can guide future research. Based on currently available data, there is insufficient evidence to support public health recommendations related to this topic. However, we cannot reject the hypothesis that the provision of vitamin D supplementation to pregnant women and/or offspring in groups vulnerable to vitamin D deficiency may subsequently reduce the incidence of schizophrenia in the offspring.

Vitamin D status and its correlation to depression

BACKGROUND

Vitamin D can influence more than 200 genes in various tissues showing its credibility among the fat-soluble vitamins. Vitamin D deficiency is directly proportional to major clinical conditions such as cardiovascular diseases, diabetes, malignancy, and multiple sclerosis. This study was conducted to determine the vitamin D level of individuals and its association with depression.

METHODS

Vitamin D levels of 100 healthy and 100 depressed subjects were determined. The isolated subjects were screened on the Beck Depression Inventory (BDI) scale and divided into three groups according to their age. Group-I comprised subjects of age 20 years and below, Group-II included subjects of age 21 to 60, and Group-III comprised subjects of ≥ 61 years of age. A sufficient level of vitamin D in normal subjects was noted, while mild deficiency of vitamin D status was observed in depressed subjects.

RESULTS

Our study has reported a higher percentage of vitamin D deficiency in the Peshawar region. The results of our study indicated that depression was common in individuals having vitamin D deficiency.

CONCLUSIONS

The study showed a very high frequency of vitamin D deficiency in subjects with depression in Peshawar, Pakistan. The deficiency of vitamin D was observed more in females as compared to males. Further studies should explicate whether the highly widespread vitamin D deficiency could be cost-effectively treated as part of preventive or treatment interventions for depression.

Vitamin D status in pregnancy and childhood associates with intelligence quotient at age 7 years: An Odense child cohort study

OBJECTIVES

Animal studies indicate a key role for vitamin D in brain development and function, but observational studies in humans only suggests a borderline positive association between prenatal vitamin D exposure and cognitive development in the offspring. Knowledge gaps include insights in exposure time window and differences by sex for the association. We aimed to investigate the association between blood concentrations of serum 25-hydroxyvitamin D measured at four different time points and intelligence quotient score at the age of 7 years, including analyses spilt by child sex.

METHODS

In Odense child cohort, we included 1404 mother-child pairs with serum 25-hydroxyvitamin D data from early pregnancy to age 7 years. Full-scale intelligence quotient was assessed with Wechsler Intelligence Scale for Children - fifth edition. Associations were adjusted for maternal education, pre-pregnancy body mass index, gestational age, sex and head circumference. Subanalyses stratified by sex were performed.

RESULTS

The median (interquartile range) serum 25-hydroxyvitamin D in cord was 45.88 (31.15-61.08) nmol/L; early pregnancy, 66.45 (51.29-78.74); late pregnancy, 79.13 (59.69-97.31); 7 years, 66.29 (53.45-80.23) nmol/L. The mean (standard deviation) full-scale intelligence quotient was 99.44 (11.98). In adjusted analyses, cord serum 25-hydroxyvitamin D < 50 nmol/L was associated with 2.2 points lower full-scale intelligence quotient compared to the reference (50-75 nmol/L) in boys, β = -2.2; 95% confidence interval = [-4.3, -0.1], p = 0.039. The same association with full-scale intelligence quotient was found for early pregnancy serum 25-hydroxyvitamin D, β = -2.5 [-4.6, -0.3], p = 0.025, primarily driven by an association in boys, β = -4.0 [-7.2, -0.8], p = 0.015; and for serum 25-hydroxyvitamin D at 7 years in girls, β = -3.0 [-6.0, -0.1], p = 0.042.

CONCLUSION

In this cohort, serum 25-hydroxyvitamin D < 50 nmol/L in both early gestation and cord blood in boys and current serum 25-hydroxyvitamin D < 50 nmol/L in girls were independent risk factors for two to four points lower full-scale intelligence quotient at the age of 7 years. Vulnerability to hypovitaminosis D, especially in pregnancy, may relate to child sex.

Vitamin D receptor gene variants and serum vitamin D in childhood autism spectrum disorder

OBJECTIVE

This study aimed to examine the correlation between polymorphisms in vitamin D receptor (VDR) gene and serum vitamin D, and to determine their role in predicting childhood Autism Spectrum Disorder (ASD).

METHODS

Children with ASD and age- and gender- matched healthy controls were recruited from the Chinese Han population. Their serum 25(OH) vitamin D was measured using competitive chemiluminescent immunoassays. The TaqMan probe approach was applied to analyze the common VDR SNPs rs731236 (Taq1), rs11568820 (Cdx2), rs1544410 (BsmI), and rs228570 (FokI). Both linear and logistic regressions were applied in data analysis.

RESULTS

A total of 269 children with ASD and 320 healthy controls were recruited. Children with ASD had significantly lower levels of serum vitamin D and a significantly higher rate of vitamin D deficiency (< 20 ng/ml) compared to healthy controls (67.7% vs 34.1%). All these examined VDR SNPs were not correlated with serum vitamin D concentrations or vitamin D deficiency. Logistic regression analysis revealed that rs731236 and serum vitamin D were associated with childhood ASD. The area under the receiver operating characteristic (ROC) curve was 0.7285 for serum vitamin D. Children with both T/C genotype of rs731236 and vitamin D deficiency had a higher risk of being diagnosed with ASD.

CONCLUSION

All examined common VDR SNPs are not correlated with serum vitamin D concentrations or vitamin D deficiency. The combination of T/C phenotype of rs731236 and vitamin D deficiency are associated with a higher risk of childhood ASD. Vitamin D is a promising target in the prevention and treatment of this disease.

Vitamin D supplementation and gross motor development: A 3-year follow-up of a randomized trial

BACKGROUND

Vitamin D status during pregnancy, early childhood and season-at-birth are implicated in gross motor development (GMD).

AIM

To test whether vitamin D intake in infancy and season-at-birth affect GMD in early childhood.

STUDY DESIGN

3-year follow up study of a single-center trial.

SUBJECTS

Healthy infants (n = 116) were allocated to 400 (standard-of-care), 800 or 1200 IU/day of vitamin D3 supplementation from 1 to 12 months; n = 70 returned for follow-up at 3-years.

OUTCOME MEASURES

The main outcome was GMD using the Peabody Developmental Motor Scales-2 which includes gross motor quotient (GMQ) and stationary, locomotion and object manipulation subtests.

RESULTS

GMQ scores were normal (≥85) in 94 %. An interaction between dosage group and season-at-birth (p = 0.01) was observed for GMQ and stationary standardized score; among winter/spring born children, the 1200 IU/d scored higher vs. 400 and 800 IU/d groups. Object manipulation standardized score was higher (p = 0.04) in children in the 1200 vs. 400 IU/d group, without interaction with season-at-birth.

CONCLUSIONS

GMD in young children who received 400 IU/d of supplemental vitamin D in infancy is not influenced by season-at-birth. This dose of vitamin D of 400 IU/d as recommended in North America adequately supports GMD. The modest enhancement in GMD with 1200 IU/d in winter/spring born children requires further study.

Plants, Plants, and More Plants: Plant-Derived Nutrients and Their Protective Roles in Cognitive Function, Alzheimer’s Disease, and Other Dementias

Background and Objectives: Alzheimer’s disease (AD) is the most common form of dementia, with the risk of developing it attributed to non-modifiable and modifiable factors. Currently, there is no cure for AD. A plant-based diet may protect against cognitive decline, due to the effects of plant-based nutrients such as vitamins, antioxidants, and fiber. The aim of the review is to summarize current literature on plant-based nutrients and their impact on cognition. Materials and Methods: A search was conducted on PubMed for clinical and murine studies, using combinations of the following words: “Alzheimer’s disease”, “dementia”, “cognition”, “plant-based diet”, “mild cognitive impairment”, “vitamin B”, “vitamin C”, “vitamin E, “beta carotene”, “antioxidants”, “fiber”, “vitamin K”, “Mediterranean diet”, “vitamin D”, and “mushrooms”. Results and Conclusions: A diet rich in vitamin B and antioxidants can benefit the cognitive functions of individuals as shown in randomized clinical trials. Vitamin K is associated with improved cognition, although large randomized controlled trials need to be done. Fiber has been shown to prevent cognitive decline in animal studies. Vitamin D may contribute to cognitive health via anti-inflammatory processes. Several medical organizations have recommended a plant-based diet for optimizing cognitive health and potentially helping to prevent dementia.

The Role of Vitamin D in Stroke Prevention and the Effects of Its Supplementation for Post-Stroke Rehabilitation: A Narrative Review

Hypovitaminosis D is a serious public health problem, representing an independent factor in mortality among the general population. Vitamin D deficiency may affect up to one billion people worldwide. Recently, the potential association between vitamin D levels and stroke has gained increasing attention. Many studies suggest that maintaining normal serum vitamin D levels is associated with improvement of the cardiovascular system and a reduction in stroke risk. As a neurosteroid, vitamin D influences brain development and function and immunomodulation and affects brain neuroplasticity. It supports many processes that maintain homeostasis in the body. As stroke is the second most common cause of death worldwide, more studies are needed to confirm the positive effects of vitamin D supplementation, its dosage at different stages of the disease, method of determination, and effect on stroke onset and recovery. Many studies on stroke survivors indicate that serum vitamin D levels only offer insignificant benefits and are not beneficial to recovery. This review article aims to highlight recent publications that have examined the potential of vitamin D supplementation to improve rehabilitation outcomes in stroke survivors. Particular attention has been paid to stroke prevention.

Molecular Basis Underlying the Therapeutic Potential of Vitamin D for the Treatment of Depression and Anxiety

Major depressive disorder and anxiety disorders are common and disabling conditions that affect millions of people worldwide. Despite being different disorders, symptoms of depression and anxiety frequently overlap in individuals, making them difficult to diagnose and treat adequately. Therefore, compounds capable of exerting beneficial effects against both disorders are of special interest. Noteworthily, vitamin D deficiency has been associated with an increased risk of developing depression and anxiety, and individuals with these psychiatric conditions have low serum levels of this vitamin. Indeed, in the last few years, vitamin D has gained attention for its many functions that go beyond its effects on calcium–phosphorus metabolism. Particularly, antioxidant, anti-inflammatory, pro-neurogenic, and neuromodulatory properties seem to contribute to its antidepressant and anxiolytic effects. Therefore, in this review, we highlight the main mechanisms that may underlie the potential antidepressant and anxiolytic effects of vitamin D. In addition, we discuss preclinical and clinical studies that support the therapeutic potential of this vitamin for the management of these disorders.

Vitamin D as a Risk Factor for Multiple Sclerosis: Immunoregulatory or Neuroprotective?

Vitamin D insufficiency during childhood has been linked to the development of multiple sclerosis (MS), typically an adult-onset inflammatory demyelinating disease of the central nervous system (CNS). Since vitamin D was known to have immunoregulatory properties on both innate and adaptive immunity, it was hypothesized that low vitamin D resulted in aberrant immune responses and the development of MS. However, vitamin D receptors are present on many cell types, including neurons, oligodendrocytes, astrocytes and microglia, and vitamin D has profound effects on development and function of the CNS. This leads to the possibility that low vitamin D may alter the CNS in a manner that makes it vulnerable to inflammation and the development of MS. This review analysis the role of vitamin D in the immune and nervous system, and how vitamin D insufficiency in children may contribute to the development of MS.

Maternal vitamin D supplementation and treadmill exercise attenuated vitamin D deficiency-induced anxiety-and depressive-like behaviors in adult male offspring rats

BACKGROUND

Vitamin D is a vital neuroactive steroid for brain development and function. Vitamin D deficiency is a worldwide health problem, particularly in children and women. Gestational or developmental vitamin D deficiency is associated with an increased risk of neurodevelopmental and neuropsychiatric disorders. This study examined the effect of maternal vitamin D dietary manipulations and treadmill exercise on anxiety-and depressive-related behaviors, pro-inflammatory cytokines, and prefrontal cortex (PFC) protein levels of brain-derived neurotrophic factor (BDNF) and vitamin D receptor (VDR) in adult male offspring born to vitamin D-deficient diet (VDD)-fed dams.

METHODS AND RESULTS

Female rats were provided standard diet (SD) or VDD for six weeks and then were treated with SD (started a week before mating throughout gestation and lactation) and treadmill exercise (a week before mating until gestational day 20). Male offspring were separated on postnatal day (PND) 21 and fed SD chow until PND90. Our results demonstrated that maternal vitamin D deficiency increased anxiety and depression-related behaviors, increased levels of TNF-α and IL-1β in serum, and decreased prefrontal protein expressions of BDNF and VDR in adult male offspring. However, maternal vitamin D supplementation and treadmill exercise reversed these changes alone or in combination.

CONCLUSION

It seems that developmental vitamin D deficiency disrupts brain development and has a long-lasting effect on VDR and BDNF signaling in the rat brain resulting in neuropsychiatric disorders in offspring. Therefore, vitamin D supplementation and physical exercise are reasonable strategies to prevent these neurobehavioral impairments.