Developmental Vitamin D3 deficiency alters the adult rat brain

The impact of adult vitamin D deficiency on behaviour and brain function in male Sprague-Dawley rats

Background

Vitamin D deficiency is common in the adult population, and this has been linked to depression and cognitive outcomes in clinical populations. The aim of this study was to investigate the effects of adult vitamin D (AVD) deficiency on behavioural tasks of relevance to neuropsychiatric disorders in male Sprague-Dawley rats.

Methods

Ten-week old male Sprague-Dawley rats were fed a control or vitamin D deficient diet for 6 weeks prior to, and during behavioural testing. We first examined a range of behavioural domains including locomotion, exploration, anxiety, social behaviour, learned helplessness, sensorimotor gating, and nociception. We then assessed locomotor response to the psychomimetic drugs, amphetamine and MK-801. Attention and vigilance were assessed using the 5 choice serial reaction time task (5C-SRT) and the 5 choice continuous performance task (5C-CPT) and, in a separate cohort, working memory was assessed using the delay match to sample (DMTS) task. We also examined excitatory and inhibitory neurotransmitters in prefrontal cortex and striatum.

Results

AVD-deficient rats were deficient in vitamin D₃ (<10 nM) and had normal calcium and phosphate levels after 8–10 weeks on the diet. Overall, AVD deficiency was not associated with an altered phenotype across the range of behavioural domains tested. On the 5C-SRT AVD-deficient rats made more premature responses and more head entries during longer inter-trial intervals (ITI) than control rats. On the 5C-CPT AVD-deficient rats took longer to make false alarm (FA) responses than control rats. AVD-deficient rats had increases in baseline GABA levels and the ratio of DOPAC/HVA within the striatum.

Conclusions

AVD-deficient rats exhibited no major impairments in any of the behavioural domains tested. Impairments in premature responses in AVD-deficient rats may indicate that these animals have specific alterations in striatal systems governing compulsive or reward-seeking behaviour.

Altered dopamine ontogeny in the developmentally vitamin D deficient rat and its relevance to schizophrenia

Schizophrenia is a heterogeneous group of disorders with unknown etiology. Although abnormalities in multiple neurotransmitter systems have been linked to schizophrenia, alterations in dopamine (DA) neurotransmission remain central to the treatment of this disorder. Given that schizophrenia is considered a neurodevelopmental disorder we have hypothesized that abnormal DA signaling in the adult patient may result from altered DA signaling during fetal brain development. Environmental and genetic risk factors can be modeled in rodents to allow for the investigation of early neurodevelopmental pathogenesis that may lead to clues into the etiology of schizophrenia. To address this we created an animal model of one such risk factor, developmental vitamin D (DVD) deficiency. DVD-deficient adult rats display an altered behavioral profile in response to DA releasing and blocking agents that are reminiscent of that seen in schizophrenia patients. Furthermore, developmental studies revealed that DVD deficiency also altered cell proliferation, apoptosis, and neurotransmission across the embryonic brain. In particular, DVD deficiency reduces the expression of crucial dopaminergic specification factors and alters DA metabolism in the developing brain. We speculate such alterations in fetal brain development may change the trajectory of DA neuron ontogeny to induce the behavioral abnormalities observed in adult offspring. The widespread evidence that both dopaminergic and structural changes are present in people who develop schizophrenia prior to onset also suggest that early alterations in development are central to the disease. Taken together, early alterations in DA ontogeny may represent a core feature in the pathology of schizophrenia. Such a mechanism could bring together evidence from multiple risk factors and genetic vulnerabilities to form a convergent pathway in disease pathophysiology.

Cholecalciferol (vitamin D₃) improves myelination and recovery after nerve injury

Previously, we demonstrated i) that ergocalciferol (vitamin D2) increases axon diameter and potentiates nerve regeneration in a rat model of transected peripheral nerve and ii) that cholecalciferol (vitamin D3) improves breathing and hyper-reflexia in a rat model of paraplegia. However, before bringing this molecule to the clinic, it was of prime importance i) to assess which form - ergocalciferol versus cholecalciferol - and which dose were the most efficient and ii) to identify the molecular pathways activated by this pleiotropic molecule. The rat left peroneal nerve was cut out on a length of 10 mm and autografted in an inverted position. Animals were treated with either cholecalciferol or ergocalciferol, at the dose of 100 or 500 IU/kg/day, or excipient (Vehicle), and compared to unlesioned rats (Control). Functional recovery of hindlimb was measured weekly, during 12 weeks, using the peroneal functional index. Ventilatory, motor and sensitive responses of the regenerated axons were recorded and histological analysis was performed. In parallel, to identify the genes regulated by vitamin D in dorsal root ganglia and/or Schwann cells, we performed an in vitro transcriptome study. We observed that cholecalciferol is more efficient than ergocalciferol and, when delivered at a high dose (500 IU/kg/day), cholecalciferol induces a significant locomotor and electrophysiological recovery. We also demonstrated that cholecalciferol increases i) the number of preserved or newly formed axons in the proximal end, ii) the mean axon diameter in the distal end, and iii) neurite myelination in both distal and proximal ends. Finally, we found a modified expression of several genes involved in axogenesis and myelination, after 24 hours of vitamin supplementation. Our study is the first to demonstrate that vitamin D acts on myelination via the activation of several myelin-associated genes. It paves the way for future randomised controlled clinical trials for peripheral nerve or spinal cord repair.

The transcriptomic response of mixed neuron-glial cell cultures to 1,25-dihydroxyvitamin d3 includes genes limiting the progression of neurodegenerative diseases

Seasonal or chronic vitamin D deficiency and/or insufficiency is highly prevalent in the human population. Receptors for 1,25-dihydroxyvitamin D3, the hormonal metabolite of vitamin D, are found throughout the brain. To provide further information on the role of this hormone on brain function, we analyzed the transcriptomic profiles of mixed neuron-glial cell cultures in response to 1,25-dihydroxyvitamin D3. 1,25-dihydroxyvitamin D3 treatment increases the mRNA levels of 27 genes by at least 1.9 fold. Among them, 17 genes were related to neurodegenerative and psychiatric diseases, or brain morphogenesis. Notably, 10 of these genes encode proteins potentially limiting the progression of Alzheimer's disease. These data provide support for a role of 1,25-dihydroxyvitamin D3 in brain disease prevention. The possible consequences of circannual or chronic vitamin D insufficiencies on a tissue with a low regenerative potential such as the brain should be considered.

Vitamin D, effects on brain development, adult brain function and the links between low levels of vitamin D and neuropsychiatric disease

Increasingly vitamin D deficiency is being associated with a number of psychiatric conditions. In particular for disorders with a developmental basis, such as autistic spectrum disorder and schizophrenia the neurobiological plausibility of this association is strengthened by the preclinical data indicating vitamin D deficiency in early life affects neuronal differentiation, axonal connectivity, dopamine ontogeny and brain structure and function. More recently epidemiological associations have been made between low vitamin D and psychiatric disorders not typically associated with abnormalities in brain development such as depression and Alzheimer's disease. Once again the preclinical findings revealing that vitamin D can regulate catecholamine levels and protect against specific Alzheimer-like pathology increase the plausibility of this link. In this review we have attempted to integrate this clinical epidemiology with potential vitamin D-mediated basic mechanisms. Throughout the review we have highlighted areas where we think future research should focus.

Vitamin D concentration and lateral cerebral ventricle volume in older adults

SCOPE

Vitamin D deficiency is associated with an enlargement of the lateral cerebral ventricles in rodents. The effect of low serum 25-hydroxyvitamin D (25OHD) on lateral cerebral ventricle volume has not been studied yet in humans. The purpose of this cross-sectional study was to determine whether vitamin D deficiency was associated with greater lateral cerebral ventricle volume in older adults.

METHODS AND RESULTS

Ninety-two Caucasian community-dwellers with no clinical hydrocephalus (mean, 72.2 ± 6.2 years; 46.7% female) were divided into two groups according to serum 25OHD concentration (deficiency ≤ 50 nmol/L; normal > 50 nmol/L). Cerebral ventricular volume was quantified using semi-automated software from three-dimensional T1-weighted MRI. Age, gender, body mass index, blood pressure, education level, Mini-Mental State Examination, white matter lesions, and serum calcium concentrations were used as covariates. There was an inverse linear association between 25OHD concentration and ventricular volume (p = 0.049). Compared to individuals with normal 25OHD, those with 25OHD deficiency (n = 33) had 28% larger lateral ventricles (46.9 ± 26.8 mL versus 36.6 ± 16.4 mL, p = 0.026). Vitamin D deficiency was associated with an increase in ventricular volume (adjustedβ = 16.55, p = 0.023). The ventricular enlargement involved ventricle bodies (p = 0.025) but not temporal horns (p = 0.112).

CONCLUSION

Serum 25OHD deficiency was associated with larger lateral cerebral ventricles. These findings provide a scientific base for vitamin D replacement trials.

Vitamin D inquiry in hippocampal neurons: consequences of vitamin D-VDR pathway disruption on calcium channel and the vitamin D requirement

Vitamin D receptor (VDR) and the enzymes involved in bioactivation of vitamin D, shown to be expressed in the central nervous system, particularly in areas affected by neurodegenerative disorders, especially in hippocampus. We showed that amyloid beta (Aβ) pathology includes VDR protein depletion and vitamin D-VDR pathway disruption either induced by Aβ or by VDR siRNA have very similar effects on cortical neurons. The goal of this study is to show the presence of 25 hydroxy vitamin D3-24 hydroxylase (24OHase) which is essential for vitamin D catabolism in hippocampal and cortical neurons. Additional goal is to compare the expression pattern of VDR and 24OHase both in hippocampal and in cortical neurons and to investigate the effects of VDR suppression in hippocampal neurons in order to see whether similar mechanisms work in hippocampus and cerebral cortex. Primary neuronal cultures were prepared from Sprague-dawley rat embryos. qRT-PCR was performed to determine VDR, 24OHase, and LVSCC-A1C mRNA expression levels. Cytotoxicity levels were determined by ELISA. Our findings illustrate that 24OHase mRNA was present both in hippocampal and in cortical neurons. VDR and 24OHase mRNA were higher in hippocampal neurons than the cortical ones. LVSCC-A1C mRNA levels increased in hippocampal neurons when VDR is down-regulated. Our results indicate that hippocampal neurons response to VDR suppression similar as cortical neurons, regarding calcium channel regulation. Higher gene expression of 24OHase and VDR might indicate "higher requirement of vitamin D" in hippocampus and potential consequences of vitamin D deficiency in cognitive decline, neurodegeneration, and Alzheimer's disease.

Effects of antipsychotics on dentate gyrus stem cell proliferation and survival in animal models: a critical update

Schizophrenia is a complex psychiatric disorder. Although a number of different hypotheses have been developed to explain its aetiopathogenesis, we are far from understanding it. There is clinical and experimental evidence indicating that neurodevelopmental factors play a major role. Disturbances in neurodevelopment might result in alterations of neuroanatomy and neurochemistry, leading to the typical symptoms observed in schizophrenia. The present paper will critically address the neurodevelopmental models underlying schizophrenia by discussing the effects of typical and atypical antipsychotics in animal models. We will specifically discuss the vitamin D deficiency model, the poly I:C model, the ketamine model, and the postnatal ventral hippocampal lesion model, all of which reflect core neurodevelopmental issues underlying schizophrenia onset.

The neurodevelopmental hypothesis of schizophrenia: convergent clues from epidemiology and neuropathology

The neurodevelopmental hypothesis of schizophrenia suggests that the disruption of early brain development increases the risk of later developing schizophrenia. This hypothesis focuses attention on critical periods of early brain development. From an epidemiologic perspective, various prenatal and perinatal risk factors have been linked to schizophrenia, including exposures related to infection, nutrition, and obstetric complications. From a genetic perspective, candidate genes have also been linked to altered brain development. In recent decades evidence from neuropathology has provided support for the neurodevelopmental hypothesis. Animal models involving early life exposures have been linked to changes in these same brain systems, providing convergent evidence for this long-standing hypothesis.

Vitamin D and autism: clinical review

BACKGROUND

Autism spectrum disorder (ASD) is a complex neurodevelopmental disorder with multiple genetic and environmental risk factors. The interplay between genetic and environmental factors has become the subject of intensified research in the last several years. Vitamin D deficiency has recently been proposed as a possible environmental risk factor for ASD.

OBJECTIVE

The aim of the current paper is to systematically review the research regarding the possible connection between ASD and vitamin D, and to provide a narrative review of the literature regarding the role of vitamin D in various biological processes in order to generate hypotheses for future research.

RESULTS

Systematic data obtained by different research groups provide some, albeit very limited, support for the possible role of vitamin D deficiency in the pathogenesis of ASD. There are two main areas of involvement of vitamin D in the human body that could potentially have direct impact on the development of ASD: (1) the brain (its homeostasis, immune system and neurodevelopment) and (2) gene regulation.

CONCLUSION

Vitamin D deficiency--either during pregnancy or early childhood--may be an environmental trigger for ASD in individuals genetically predisposed for the broad phenotype of autism. On the basis of the results of the present review, we argue for the recognition of this possibly important role of vitamin D in ASD, and for urgent research in the field.

Prenatal vitamin D deficiency induces an early and more severe experimental autoimmune encephalomyelitis in the second generation

In a previous study, we demonstrated that mouse adult F(1) offspring, exposed to a vitamin D deficiency during pregnancy, developed a less severe and delayed Experimental Autoimmune Encephalomyelitis (EAE), when compared with control offspring. We then wondered whether a similar response was observed in the subsequent generation. To answer this question, we assessed F(2) females whose F(1) parents (males or females) were vitamin D-deprived when developing in the uterus of F(0) females. Unexpectedly, we observed that the vitamin D deficiency affecting the F(0) pregnant mice induced a precocious and more severe EAE in the F(2) generation. This paradoxical finding led us to assess its implications for the epidemiology of Multiple Sclerosis (MS) in humans. Using the REFGENSEP database for MS trios (the patient and his/her parents), we collected the parents' dates of birth and assessed a potential season of birth effect that could potentially be indicative of the vitamin D status of the pregnant grandmothers. A trend for a reduced number of births in the Fall for the parents of MS patients was observed but statistical significance was not reached. Further well powered studies are warranted to validate the latter finding.

Possibility of a new anti-alzheimer's disease pharmaceutical composition combining memantine and vitamin D

Alzheimer's disease (AD) is the leading cause of dementia. In addition to a decrease in brain cholinergic activity, AD is also marked by glutamatergic excitotoxicity that results in neuronal death, characterized clinically by a loss of learning and memory abilities. The currently available drugs for symptomatic treatment of AD (i.e. memantine and acetylcholinesterase inhibitors) only temporarily slow down the natural history of the disease process. Among them, memantine is the only one that acts as a non-competitive low-affinity modulator of N-methyl-D-aspartate (NMDA) receptors. Memantine's modulation of NMDA receptors has been reported to prevent the neuronal necrosis induced by glutamatergic calcium neurotoxicity, but not the neuronal apoptosis resulting from oxidative stress. This observation calls for new drug regimen strategies based on memantine combined with molecules having antioxidant effects, in order to create a multi-target therapy to increase neuronal protection and prevent AD progression. We wish to highlight that vitamin D is a secosteroid hormone that is suggested to have neuroprotective effects that include regulation of neuronal calcium homeostasis, as well as antioxidant, neurotrophic and anti-inflammatory properties. The combination of memantine plus vitamin D may provide, in one treatment, enhanced protection against several degenerative processes linked to AD. Based on the present rationale, a clinical trial testing this hypothesis is currently in recruitment (AD-IDEA trial; ClinicalTrials.gov identifier: NCT01409694). This new pharmaceutical composition may provide an effective solution to the problem of neuronal death and cognitive decline in AD.

Attentional processing in C57BL/6J mice exposed to developmental vitamin D deficiency

Epidemiological evidence suggests that Developmental Vitamin D (DVD) deficiency is associated with an increased risk of schizophrenia. DVD deficiency in mice is associated with altered behaviour, however there has been no detailed investigation of cognitive behaviours in DVD-deficient mice. The aim of this study was to determine the effect of DVD deficiency on a range of cognitive tasks assessing attentional processing in C57BL/6J mice. DVD deficiency was established by feeding female C57BL/6J mice a vitamin D-deficient diet from four weeks of age. After six weeks on the diet, vitamin D-deficient and control females were mated with vitamin D-normal males and upon birth of the pups, all dams were returned to a diet containing vitamin D. The adult offspring were tested on a range of cognitive behavioural tests, including the five-choice serial reaction task (5C-SRT) and five-choice continuous performance test (5C-CPT), as well as latent inhibition using a fear conditioning paradigm. DVD deficiency was not associated with altered attentional performance on the 5C-SRT. In the 5C-CPT DVD-deficient male mice exhibited an impairment in inhibiting repetitive responses by making more perseverative responses, with no changes in premature or false alarm responding. DVD deficiency did not affect the acquisition or retention of cued fear conditioning, nor did it affect the expression of latent inhibition using a fear conditioning paradigm. DVD-deficient mice exhibited no major impairments in any of the cognitive domains tested. However, impairments in perseverative responding in DVD-deficient mice may indicate that these animals have specific alterations in systems governing compulsive or reward-seeking behaviour.

Vitamin D bioavailability in cystic fibrosis: a cause for concern?

Despite the inclusion of extra vitamin D in their regimen of fat-soluble vitamin supplementation, cystic fibrosis patients remain chronically depleted of vitamin D. The persistence of suboptimal vitamin D status is often blamed on the maldigestion and malabsorption of fat. However, the mitigated success of recent clinical trials with high-dose vitamin D supplementation suggests that vitamin D bioavailability might be impaired in these patients. Given the growing understanding of the importance of this vitamin in the regulation of multiple biological functions beyond skeletal health, the present review analyzes the current literature by addressing each step of vitamin D metabolism and action in the context of this life-limiting pathology. In addition, it highlights the importance of vitamin D in relation to organs and or conditions affected by cystic fibrosis.

Role of vitamin d in Parkinson's disease

Parkinson's disease (PD) is the second most common form of neurodegeneration in the elderly population. Clinically, it is characterized by tremor, rigidity, slowness of movement, and postural imbalance. A significant association between low serum vitamin D and PD has been demonstrated, suggesting that elevated vitamin D levels might provide protection against PD. Genetic studies have helped identify a number of proteins linking vitamin D to PD pathology, including the major histocompatibility complex (MHC) class II, the vitamin D receptor (VDR), cytochrome P450 2D6 (CYP2D6), chromosome 22, the renin-angiotensin system (RAS), heme oxygenase-1 (HO-1), poly(ADP-ribose) polymerase-1 gene (PARP-1), neurotrophic factor (NTF), and Sp1 transcription factor. Vitamin D has also been implicated in PD through its effects on L-type voltage-sensitive calcium channels (L-VSCC), nerve growth factor (NGF), matrix metalloproteinases (MMPs), prostaglandins (PGs) and cyclooxygenase-2 (COX-2), reactive oxygen species (ROS), and nitric oxide synthase (NOS). A growing body of evidence suggests that vitamin D supplementation may be beneficial for PD patients. Among the different forms of vitamin D, calcitriol (1,25-dihydroxyvitamin D₃) is best indicated for PD, because it is a highly active vitamin D₃ metabolite with an appropriate receptor in the central nervous system (CNS).

Schizophrenia: do all roads lead to dopamine or is this where they start? Evidence from two epidemiologically informed developmental rodent models

The idea that there is some sort of abnormality in dopamine (DA) signalling is one of the more enduring hypotheses in schizophrenia research. Opinion leaders have published recent perspectives on the aetiology of this disorder with provocative titles such as 'Risk factors for schizophrenia--all roads lead to dopamine' or 'The dopamine hypothesis of schizophrenia--the final common pathway'. Perhaps, the other most enduring idea about schizophrenia is that it is a neurodevelopmental disorder. Those of us that model schizophrenia developmental risk-factor epidemiology in animals in an attempt to understand how this may translate to abnormal brain function have consistently shown that as adults these animals display behavioural, cognitive and pharmacological abnormalities consistent with aberrant DA signalling. The burning question remains how can in utero exposure to specific (environmental) insults induce persistent abnormalities in DA signalling in the adult? In this review, we summarize convergent evidence from two well-described developmental animal models, namely maternal immune activation and developmental vitamin D deficiency that begin to address this question. The adult offspring resulting from these two models consistently reveal locomotor abnormalities in response to DA-releasing or -blocking drugs. Additionally, as adults these animals have DA-related attentional and/or sensorimotor gating deficits. These findings are consistent with many other developmental animal models. However, the authors of this perspective have recently refocused their attention on very early aspects of DA ontogeny and describe reductions in genes that induce or specify dopaminergic phenotype in the embryonic brain and early changes in DA turnover suggesting that the origins of these behavioural abnormalities in adults may be traced to early alterations in DA ontogeny. Whether the convergent findings from these two models can be extended to other developmental animal models for this disease is at present unknown as such early brain alterations are rarely examined. Although it is premature to conclude that such mechanisms could be operating in other developmental animal models for schizophrenia, our convergent data have led us to propose that rather than all roads leading to DA, perhaps, this may be where they start.

Neuroanatomy and psychomimetic-induced locomotion in C57BL/6J and 129/X1SvJ mice exposed to developmental vitamin D deficiency

Evidence from epidemiology suggests that developmental vitamin D (DVD) deficiency is associated with an increased risk of schizophrenia. DVD deficiency in rats is associated with altered brain morphology and enhanced hyperlocomotion in response to MK-801 and amphetamine. The aim of this study was to determine if similar phenotypes were associated with DVD deficiency in two strains of mice (C57BL/6J, 129/X1SvJ). Brains from neonatal (P0) and adult (P70) mice were imaged using MRI and the volumes of the cerebrum, hippocampus, striatum, septum, cortex and ventricles measured, as well as the widths of white matter tracts. Locomotor sensitivity to 5mg/kg d-amphetamine, 0.5mg/kg MK-801 or saline was examined in a separate group of mice in an open field. DVD deficiency altered brain morphology in C57BL6/J mice, such that C57BL/6J female DVD-deficient neonatal mice had a smaller hippocampus compared to female controls. In addition, adult C57BL/6J male DVD-deficient mice had smaller lateral ventricles compared to controls, which may have been compressed by the enlarged striatum seen in these DVD-deficient mice. However, in contrast to the behavioural phenotypes found in DVD-deficient rats, there was no significant effect of maternal diet on amphetamine or MK-801-induced locomotion in either strain. These data indicate that not only species, but also strain of mouse, moderates the impact of DVD deficiency on neuroanatomical and behavioural phenotypes in rodent animal models.

The effects of vitamin D on brain development and adult brain function

A role for vitamin D in brain development and function has been gaining support over the last decade. Multiple lines of evidence suggest that this vitamin is actually a neuroactive steroid that acts on brain development, leading to alterations in brain neurochemistry and adult brain function. Early deficiencies have been linked with neuropsychiatric disorders, such as schizophrenia, and adult deficiencies have been associated with a host of adverse brain outcomes, including Parkinson's disease, Alzheimer's disease, depression and cognitive decline. This review summarises the current state of research on the actions of vitamin D in the brain and the consequences of deficiencies in this vitamin. Furthermore, we discuss specific implications of vitamin D status on the neurotransmitter, dopamine.

The beneficial role of vitamin D in Alzheimer's disease

Alzheimer's disease (AD) is the most common form of dementia in the elderly individuals and is associated with progressive neurodegeneration of the human neocortex. Patients with AD have a high prevalence of vitamin D deficiency, which is also associated with low mood and impaired cognitive performance in older people. Genetic studies have provided the opportunity to determine which proteins link vitamin D to AD pathology (ie, the major histocompatibility complex class II molecules, vitamin D receptor, renin-angiotensin system, apolipoprotein E, liver X receptor, Sp1 promoter gene, and the poly(ADP-ribose) polymerase-1 gene). Vitamin D also exerts its effect on AD through nongenomic factors, that is, L-type voltage-sensitive calcium channels, nerve growth factor, the prostaglandins, cyclooxygenase 2, reactive oxygen species, and nitric oxide synthase. In conclusion, vitamin D clearly has a beneficial role in AD and improves cognitive function in some patients with AD. Calcitriol, 1 α,25-dihydroxyvitamin D3, is best used for AD because of its active form of vitamin D(3) metabolite and its receptor in the central nervous system.

Lack of correlation between first trimester maternal serum 25-hydroxyvitamin D levels and ultrasound measured crown-rump length and nuchal translucency

BACKGROUND

Vitamin D regulates the human genome and it is thought to influence the fetal growth and development, but its relation to early ultrasound fetal measures is still unknown.

OBJECTIVE

To assess first trimester 25-hydroxyvitamin D [25(OH)D] maternal serum status and correlate with ultrasound crown-rump length (CRL) and nuchal translucency (NT) measurements.

METHOD

In this cross-sectional study, women with singleton pregnancies undergoing the first trimester standard two-dimensional ultrasound scan for fetal anomalies were included: CRL (n = 498) and NT (n = 487). Concomitantly, maternal serum 25(OH)D levels were also measured.

RESULTS

Median serum 25(OH)D levels for the entire sample (n = 498) was 27.4 ng/mL (interquartile range 20.9-32.7). Serum 25(OH)D was adequate (≥ 30 ng/mL) in only 36.1% of gravids, whereas levels were found to be insufficient (20-29.99 ng/mL) in 41.2% and deficient (< 20 ng/mL) in 22.7%. No significant correlation was found between the serum 25(OH)D levels and the measured ultrasound parameters.

CONCLUSION

First trimester 25(OH)D levels did not correlate to fetal ultrasound measurements.

Micronutrients in pregnancy: current knowledge and unresolved questions

Micronutrient status is increasingly recognized to play an important role in the health and well-being of pregnant women and in the development and long-term health of the offspring. On 26th - 28th February 2009, The Child Health Foundation invited leading experts in this area to a scientific workshop at Obergurgl, Austria to review and critically discuss current knowledge, to identify issues that may need to be addressed in future recommendations, and to highlight priorities and opportunities for future research. This report summarizes updated key conclusions of the workshop with regards to micronutrients' intake and physiological role related to mother, placenta and fetus, as well as relevance for adverse pregnancy and long-term outcomes.

Vitamin D in the healthy and inflamed central nervous system: access and function

High exposure to vitamin D may protect against development and progression of multiple sclerosis (MS), possibly through the immunomodulatory properties of its biologically active metabolite 1,25-dihydroxyvitamin D. So far, most studies on the possible mechanisms for vitamin D involvement in MS have focused on immune modulation outside the central nervous system (CNS). However, vitamin D may also interfere with the pathophysiology of MS within the CNS. In this review, the potential presence and functions of vitamin D in the inflamed and healthy CNS are explored. We discuss that vitamin D, vitamin D binding protein (DBP), the vitamin D receptor (VDR) and enzymes needed for metabolism (CYP27B1) are present in the CNS. Both VDR and CYP27B1 are expressed on a variety of cells, including neurons, glial cells, and invading lymphocytes. Additionally, vitamin D has been postulated to play a modulating role in several key-processes in MS pathophysiology, including inflammation, demyelination, axonal damage, and remyelination. We conclude that a local role of vitamin D in the inflamed CNS is likely and potentially relevant to MS. Future studies should further characterize the impact of vitamin D on the local disease process of MS in the CNS.

Vitamin D and the brain

Vitamin D is a member of the superfamily of nuclear steroid transcription regulators and as such, exerts transcriptional control over a large number of genes. Several other steroids, such as thyroid hormones, vitamin A, androgens and the glucocorticoids, are known as 'neurosteroids' and their role in brain development and function is well defined. It has only been in the last decade or so that vitamin D has been thought to function as a neurosteroid. In this review we have collated a diverse array of data describing the presence of vitamin D metabolites and the receptor in the brain, the evidence that vitamin D may be an important modulator of brain development, and the potential role of vitamin D in neurological and neuropsychiatric disorders.

Nuclear lipid microdomains regulate nuclear vitamin D3 uptake and influence embryonic hippocampal cell differentiation

Despite recent advances in the understanding of the role of 1,25-dihydroxyvitamin D(3) (1,25-(OH)(2)D(3)) in the CNS, the mechanism of action remains obscure. We demonstrate that some 1,25-(OH)(2)D(3) receptor (VDR) is localized in the cell nucleus in specialized microdomains enriched in sphingomyelin and cholesterol; the integrity of these microdomains is necessary for embryonic hippocampal cell differentiation. Sphingomyelinase (SMase) treatment reduces both VDR and labeled 1,25-(OH)(2)D(3) content in nuclear microdomains. We have previously shown that HN9.10e embryonic hippocampal cells differentiate when incubated with 100 nM 1,25-(OH)(2)D(3) in the presence of 10% fetal calf serum, while serum deprivation induces cell death. In this study, we have investigated whether conditions that alter lipid content of nuclear microdomains modify 1,25-(OH)(2)D(3)-induced differentiation. Serum deprivation activates SMase and modifies the composition of nuclear microdomains, which lose the 1,25-(OH)(2) vitamin D(3) receptor. The incubation of serum-deprived cells with 100 nM 1,25-(OH)(2)D(3) prevents differentiation. However, treatment with 400 nM 1,25-(OH)(2)D(3) during serum withdrawal increases the lipid content of the nuclear microdomains, allows the interaction of 1,25-(OH)(2)D(3) with its receptor, and results in differentiation. These results suggest the presence of VDR in nuclear microdomains is necessary for 1,25-(OH)(2)D(3)-induced differentiation in embryonic hippocampal cells.

Prevalence of autism according to maternal immigrant status and ethnic origin

OBJECTIVE

To examine the rates of autism separately according to maternal immigrant status and ethnic origin in respect to the vitamin D insufficiency hypothesis.

METHOD

Articles were identified by electronic searches. Studies were selected when they analysed autism rates according to maternal immigrant status and/or ethnic origin using multivariate techniques.

RESULTS

This review gave further support to the association between maternal immigrant status and an increased risk of autism. The relationship with ethnic origin was more complex. Although the crude rates did not differ, multivariate analyses taking into account confounding factors found that black ethnicity was associated with an increased risk for autism. The risk was highly significant when considering the strict definition of autistic disorders as opposed to the large definition of other pervasive developmental disorders. The risk was also very significant for autism associated with mental retardation.

CONCLUSION

These results are consistent with the maternal vitamin D insufficiency hypothesis. Neurobiological studies are warranted to document the effect of maternal vitamin D insufficiency during pregnancy on the foetal brain and the window of vulnerability. This review stresses the importance of monitoring vitamin D levels in pregnant women, especially those who are immigrant, dark-skinned or veiled, and the urgency of randomized controlled trials.

The effects of vitamin D receptor silencing on the expression of LVSCC-A1C and LVSCC-A1D and the release of NGF in cortical neurons

Background

Recent studies have suggested that vitamin D can act on cells in the nervous system. Associations between polymorphisms in the vitamin D receptor (VDR), age- dependent cognitive decline, and insufficient serum 25 hydroxyvitamin D₃ levels in Alzheimer's patients and elderly people with cognitive decline have been reported. We have previously shown that amyloid β (Aβ) treatment eliminates VDR protein in cortical neurons. These results suggest a potential role for vitamin D and vitamin D-mediated mechanisms in Alzheimer's disease (AD) and neurodegeneration. Vitamin D has been shown to down-regulate the L-type voltage-sensitive calcium channels, LVSCC-A1C and LVSCC-A1D, and up-regulate nerve growth factor (NGF). However, expression of these proteins when VDR is repressed is unknown. The aim of this study is to investigate LVSCC-A1C, LVSCC-A1D expression levels and NGF release in VDR-silenced primary cortical neurons prepared from Sprague-Dawley rat embryos.

Methodology/Principal Findings

qRT-PCR and western blots were performed to determine VDR, LVSCC-A1C and -A1D expression levels. NGF and cytotoxicity levels were determined by ELISA. Apoptosis was determined by TUNEL. Our findings illustrate that LVSCC-A1C mRNA and protein levels increased rapidly in cortical neurons when VDR is down-regulated, whereas, LVSCC-A1D mRNA and protein levels did not change and NGF release decreased in response to VDR down-regulation. Although vitamin D regulates LVSCC-A1C through VDR, it may not regulate LVSCC-A1D through VDR.

Conclusions/Significance

Our results indicate that suppression of VDR disrupts LVSCC-A1C and NGF production. In addition, when VDR is suppressed, neurons could be vulnerable to aging and neurodegeneration, and when combined with Aβ toxicity, it is possible to explain some of the events that occur during neurodegeneration.

Prevention and schizophrenia--the role of dietary factors

Adequate prenatal nutrition is essential for optimal brain development. There is a growing body of evidence from epidemiology linking exposure to nutritional deprivation and increased risk of schizophrenia. Based on studies from the Netherlands and China, those exposed to macronutrient deficiencies during famine have an increased risk of schizophrenia. With respect to micronutrients, we focus on 3 candidates where there is biological plausibility for a role in this disorder and at least 1 study of an association with schizophrenia. These nutrients include vitamin D, folic acid, and iron. While the current evidence is incomplete, we discuss the potential implications of these findings for the prevention of schizophrenia. We argue that schizophrenia can draw inspiration from public health interventions related to prenatal nutrition and other outcomes and speculate on relevant factors that bear on the nature, risks, impact, and logistics of various nutritional strategies that may be employed to prevent this disorder.

Abnormal neurogenesis in the dentate gyrus of adult mice lacking 1,25-dihydroxy vitamin D3 (1,25-(OH)2 D3)

In this study, we employed 1α-hydroxylase knockout (1α-(OH)ase(-/-) ) mice to investigate the influence of 1,25-dihydroxy vitamin D(3) (1,25-(OH)(2) D(3) ) deficiency on the adult neurogenesis in the hippocampal dentate gyrus (DG). The numbers of both 24-hr-old BrdU(+) cells and proliferating cell nuclear antigen positive cells in 8-week-old 1α-(OH)ase(-/-) mice increased approximately twofold compared with wild-type littermates. In contrast, the numbers of 7- and 28-day-old BrdU(+) cells in 1α-(OH)ase(-/-) mice decreased by 50% compared with wild-type mice, while the proportion of BrdU(+) /NeuN(+) cells in BrdU(+) population showed no difference between 1α-(OH)ase(-/-) and wild-type mice. Apoptotic cells in the subgranular zone (SGZ) of DG markedly increased in 1α-(OH)ase(-/-) mice. Replenishment of 1,25-(OH)(2) D(3) , but not correction of serum calcium and phosphorus levels, completely prevented changes in the neurogenesis in 1α-(OH)ase(-/-) mice. The absence of 1,25-(OH)(2) D(3) led to an increase in the expression of L-type voltage-gated calcium channel (L-VGCC) and a decrease in the nerve growth factor (NGF) mRNA level. Treatment with the L-VGCC inhibitor nifedipine blocked the increased cell proliferations by 1,25-(OH)(2) D(3) deficiency. Administration of NGF significantly attenuated the loss of newborn neurons in 1α-(OH)ase(-/-) mice.

Developmental vitamin D deficiency and risk of schizophrenia: a 10-year update

There is an urgent need to generate and test candidate risk factors that may explain gradients in the incidence of schizophrenia. Based on clues from epidemiology, we proposed that developmental vitamin D deficiency may contribute to the risk of developing schizophrenia. This hypothesis may explain diverse epidemiological findings including season of birth, the latitude gradients in incidence and prevalence, the increased risk in dark-skinned migrants to certain countries, and the urban-rural gradient. Animal experiments demonstrate that transient prenatal hypovitaminosis D is associated with persisting changes in brain structure and function, including convergent evidence of altered dopaminergic function. A recent case-control study based on neonatal blood samples identified a significant association between neonatal vitamin D status and risk of schizophrenia. This article provides a concise summary of the epidemiological and animal experimental research that has explored this hypothesis.

Fall prevention and vitamin D in the elderly: an overview of the key role of the non-bone effects

Preventing falls and fall-related fractures in the elderly is an objective yet to be reached. There is increasing evidence that a supplementation of vitamin D and/or of calcium may reduce the fall and fracture rates. A vitamin D-calcium supplement appears to have a high potential due to its simple application and its low cost. However, published studies have shown conflicting results as some studies failed to show any effect, while others reported a significant decrease of falls and fractures. Through a 15-year literature overview, and after a brief reminder on mechanism of falls in older adults, we reported evidences for a vitamin D action on postural adaptations - i.e., muscles and central nervous system - which may explain the decreased fall and bone fracture rates and we underlined the reasons for differences and controversies between published data. Vitamin D supplementation should thus be integrated into primary and secondary fall prevention strategies in older adults.

Cognitive and emotional processing associated with the Season of Birth and dopamine D4 receptor gene

The 7-repeats variant of the dopamine D4 receptor (7R) VNTR polymorphism has been associated with higher novelty seeking (NS) and disadvantageous decision making in the Iowa Gambling Task (IGT). Season of Birth (SOB) is a significant determinant of NS. SOB and L-DRD4 genetic polymorphism may independently and interactively influence similar behaviors through their common effects on the dopaminergic system. Two hundred and twenty-seven healthy males grouped in summer-born/4-repeats (4R) (n=75), winter-born/4R (n=90), summer-born/7R (n=31) and winter-born/7R (n=31) groups, completed multimodal assessment for personality, planning for problem solving and decision making. Winter-born/7R subjects had significantly worse IGT performance throughout the task compared to 4R individuals, while summer-born 7R subjects had intermediate, although not significantly different performance. Moreover, winter-born/7R subjects had increased behavioral approach to reward without parallel reduction in sensitivity to fear or to social approval cues. The DRD4-by-SOB groups did not differ in planning for problem solving. These results suggest that a DRD4-by-SOB interaction is associated with increased behavioral approach to reward and risk taking but efficient problem solving. In addition, these results further support the hypothesis that SOB modifies the behavioral expression of dopaminergic genetic polymorphism. SOB should be included in future studies of risky behaviors and behavioral genetic studies of the dopamine system.

Neurodevelopmental animal models of schizophrenia: role in novel drug discovery and development

Schizophrenia is a devastating mental illness that is associated with a lifetime of disability. For patients to successfully function in society, the amelioration of disease symptoms is imperative. The recently published results of two large antipsychotic clinical trials (e.g., CATIE, CUtLASS) clearly exemplified the limitations of currently available treatment options for schizophrenia, and further highlighted the critical need for novel drug discovery and development in this field. One of the biggest challenges in schizophrenia-related drug discovery is to find an appropriate animal model of the illness so that novel hypotheses can be tested at the basic science level. A number of pharmacological, genetic, and neurodevelopmental models have been introduced; however, none of these models has been rigorously evaluated for translational relevance or to satisfy requirements of "face," "construct" and "predictive" validity. Given the apparent polygenic nature of schizophrenia and the limited translational significance of pharmacological models, neurodevelopmental models may offer the best chance of success. The purpose of this review is to provide a general overview of the various neurodevelopmental models of schizophrenia that have been introduced to date, and to summarize their behavioral and neurochemical phenotypes that may be useful from a drug discovery and development standpoint. While it may be that, in the final analysis, no single animal model will satisfy all the requirements necessary for drug discovery purposes, several of the models may be useful for modeling various phenomenological and pathophysiological components of schizophrenia that could be targeted independently with separate molecules or multi-target drugs.

Disease-specific, neurosphere-derived cells as models for brain disorders

There is a pressing need for patient-derived cell models of brain diseases that are relevant and robust enough to produce the large quantities of cells required for molecular and functional analyses. We describe here a new cell model based on patient-derived cells from the human olfactory mucosa, the organ of smell, which regenerates throughout life from neural stem cells. Olfactory mucosa biopsies were obtained from healthy controls and patients with either schizophrenia, a neurodevelopmental psychiatric disorder, or Parkinson's disease, a neurodegenerative disease. Biopsies were dissociated and grown as neurospheres in defined medium. Neurosphere-derived cell lines were grown in serum-containing medium as adherent monolayers and stored frozen. By comparing 42 patient and control cell lines we demonstrated significant disease-specific alterations in gene expression, protein expression and cell function, including dysregulated neurodevelopmental pathways in schizophrenia and dysregulated mitochondrial function, oxidative stress and xenobiotic metabolism in Parkinson's disease. The study has identified new candidate genes and cell pathways for future investigation. Fibroblasts from schizophrenia patients did not show these differences. Olfactory neurosphere-derived cells have many advantages over embryonic stem cells and induced pluripotent stem cells as models for brain diseases. They do not require genetic reprogramming and they can be obtained from adults with complex genetic diseases. They will be useful for understanding disease aetiology, for diagnostics and for drug discovery.