Developmental Vitamin D3 deficiency alters the adult rat brain

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.

Severity of experimental autoimmune encephalomyelitis is unexpectedly reduced in mice born to vitamin D-deficient mothers

Accumulating data indicate that vitamin D, a sun-induced hormone, plays a key role in multiple sclerosis (MS) etiology. Notably, it has been shown that there is a remarkable season of birth effect in MS. We surmised that gestational vitamin D deficiency is a risk factor for MS. To test this hypothesis, a vitamin D deficiency was induced in C57BL/6 female mice 6 weeks prior to conception and prolonged until offspring birth. Contrary to our prediction, we show here that adult offspring exposed to developmental vitamin D deficiency (DVD) developed a striking milder and delayed experimental autoimmune encephalomyelitis (EAE), when compared to control offspring. Using reverse transcription and quantitative real-time PCR, we measured the expression level of 22 candidate transcripts in the spleen, the cerebrum and the spinal cord, at Day0 and Day30 post-immunization. We report here that, at Day30 post-immunization, TNF, osteopontin, H2-Eb were over-expressed and IFN was under-expressed in the spinal cord of control mice and not in DVD mice. Another discrepancy between nervous and immune systems was observed: expression of IL4 was dysregulated exclusively in the spleen. Reduced symptom severity in DVD mice can partially be explained by a nervous system-restricted over-expression of vitamin D receptor (VDR), two heat shock proteins (HSP90, HSPa8) and FK506 binding protein 1a (FKBP1a), at Day0. Our clinical test and molecular findings converge to indicate that maternal hypovitaminosis D imprints the foetus and alters the susceptibility of the offspring to EAE. We propose a new hypothesis to explain our unexpected observations.

Assessing vitamin D in the central nervous system

Epidemiological and experimental evidence suggest that vitamin D deficiency is a risk factor for multiple sclerosis and other autoimmune diseases. The activated form of vitamin D exerts several immunomodulating properties in vitro and in vivo, that could contribute to explain the association with multiple sclerosis. Hypovitaminosis D is also associated with several other neurological diseases that is less likely mediated by dysregulated immune responses, including Parkinson's disease and Alzheimer's disease, schizophrenia and affective disorders, suggesting a more diverse role for vitamin D in the maintenance of brain health. Accordingly, both the vitamin D receptor and the enzymes necessary to synthesize bioactive 1,25-dihydroxyvitamin D are expressed in the brain, and hypovitaminosis D is associated with abnormal development and function of the brain. We here review current knowledge on the intrathecal vitamin D homeostasis in heath and disease, highlighting the need to assess vitamin D in the intrathecal compartment.

Dietary intake of fish, omega-3, omega-6 polyunsaturated fatty acids and vitamin D and the prevalence of psychotic-like symptoms in a cohort of 33,000 women from the general population

BACKGROUND

Low intake of fish, polyunsaturated fatty acids (PUFA) and vitamin D deficiency has been suggested to play a role in the development of schizophrenia. Our aim was to evaluate the association between the intake of different fish species, PUFA and vitamin D and the prevalence of psychotic-like symptoms in a population-based study among Swedish women.

METHODS

Dietary intake was estimated using a food frequency questionnaire among 33,623 women aged 30-49 years at enrollment (1991/92). Information on psychotic-like symptoms was derived from a follow-up questionnaire in the years 2002/03. Participants were classified into three predefined levels: low, middle and high frequency of symptoms. The association between diet and psychotic-like symptoms was summarized in terms of relative risks (RR) and corresponding 95% confidence intervals and was evaluated by energy-adjusted multinomial logistic regression.

RESULTS

18,411 women were classified as having a low level of psychotic-like symptoms, 14 395 as middle and 817 as having a high level. The risk of high level symptoms was 53% (95% CI, 30-69%) lower among women who ate fish 3-4 times per week compared to women who never ate fish. The risk was also lower for women with a high intake of omega-3 and omega-6 PUFA compared to women with a lower intake of these fatty acids. The effect was most pronounced for omega-6 PUFAs. The RR comparing the highest to the lowest quartile of omega-6 PUFAs intake was 0.78 (95% CI, 0.64-0.97). The associations were J-shaped with the strongest reduced risk for an intermediate intake of fish or PUFA. For fatty fish (herring/mackerel, salmon-type fish), the strongest inverse association was found for an intermediate intake (RR: 0.81, 95% CI, 0.66-0.98), whereas a high intake of fatty fish was associated with an increased risk of psychotic-like symptoms (RR: 1.90, 95% CI, 1.34-2.70). Women in the highest compared with the lowest quartile of vitamin D consumption experienced a 37% (95% CI, 22-50%) lower risk of psychotic-like symptoms.

CONCLUSION

Our findings raise a possibility that adult women with a high intake of fish, omega-3 or omega-6 PUFA and vitamin D have a lower rate of psychotic-like symptoms.

Understanding and determining the etiology of autism

Worldwide, the rate of autism has been steadily rising. There are several environmental factors in concert with genetic susceptibilities that are contributing to this rise. Impaired methylation and mutations of mecp2 have been associated with autistic spectrum disorders, and related Rett syndrome. Genetic polymorphisms of cytochrome P450 enzymes have also been linked to autism, specifically CYP27B1 that is essential for proper vitamin D metabolism. Vitamin D is important for neuronal growth and neurodevelopment, and defects in metabolism or deficiency have been implicated in autistic individuals. Other factors that have been considered include: maternally derived antibodies, maternal infection, heavy metal exposure, folic acid supplementation, epigenetics, measles, mumps, rubella vaccination, and even electromagnetic radiation. In each case, the consequences, whether direct or indirect, negatively affect the nervous system, neurodevelopment, and environmental responsive genes. The etiology of autism is a topic of controversial debate, while researchers strive to achieve a common objective. The goal is to identify the cause(s) of autism to understand the complex interplay between environment and gene regulation. There is optimism that specific causes and risk factors will be identified. The results of future investigations will facilitate enhanced screening, prevention, and therapy for "at risk" and autistic patients.

Vitamin D status during pregnancy and aspects of offspring health

Low maternal vitamin D levels during pregnancy have been linked to various health outcomes in the offspring, ranging from periconceptional effects to diseases of adult onset. Maternal and infant cord 25(OH)D levels are highly correlated. Here, we review the available evidence for these adverse health effects. Most of the evidence has arisen from observational epidemiological studies, but randomized controlled trials are now underway. The evidence to date supports that women should be monitored and treated for vitamin D deficiency during pregnancy but optimal and upper limit serum 25(OH)D levels during pregnancy are not known.

Expression and regulation of vitamin D3 upregulated protein 1 (VDUP1) is conserved in mammalian and insect brain

Originally characterized as a cell-cycle inhibitor induced by vitamin D(3), the tumor suppressor vitamin-D(3) upregulated protein 1 (VDUP1) has increasingly been shown to play major physiological roles in cell differentiation and glucose metabolism. Here we show evolutionarily conserved expression patterns of VDUP1 in Drosophila and rat nervous systems, including subcellular localization--cytoplasmic enrichment in neurons and nuclear expression in glia. These anatomical correlates suggested conservation of VDUP1 regulation, which was investigated both functionally and through promoter studies. Characterization of orthologous vdup1 cis-regulatory regions identified evolutionarily conserved sequence blocks (CSBs) with similarities to neural enhancers, including basic helix-loop-helix (bHLH) transcription factor Neurogenin/Math/atonal and Mash/achaete-scute family members. E-boxes (CANNTG), the binding sites for bHLH proteins, were associated with these CSBs as well, including E-boxes known to mediate glucose-dependent upregulation of VDUP1 in nonneuronal cells. Hyperglycemia-induced upregulation of VDUP1 was observed in brain tumor cells and in the Drosophila nervous system, which resulted in developmental arrest. Taken together, these data demonstrate evolutionary conservation of VDUP1 regulation and function, and suggest an expanding role for VDUP1 in nervous system development.

Developmental vitamin D deficiency alters learning in C57Bl/6J mice

Epidemiological studies have highlighted a season of birth effect in multiple sclerosis and schizophrenia. As a result, low prenatal vitamin D has been proposed as a candidate risk factor for these brain diseases, with cognitive impairments. In order to further investigate the long-term consequences of a transient gestational hypovitaminosis D, we used a mouse developmental vitamin D (DVD) deficiency model. Female C57Bl/6J mice were fed a vitamin D-free diet for 6 weeks prior to conception and during gestation. At birth, dams and their offspring were fed a normal vitamin D-containing diet. The adult offspring underwent a learning test based on olfactory cues, at 30 weeks and 60 weeks of age. In addition, using magnetic resonance imaging (MRI), volumes of cerebrum, hippocampus and lateral ventricles were measured at 30 weeks and 70 weeks of age. We found that DVD-deficient mice, when compared to control animals at Week 30, displayed impaired learning and smaller lateral ventricles. At Weeks 60-70, both groups deteriorated when compared to young mice and no significant difference was observed between groups. This study confirms that transient prenatal vitamin D deficiency alters brain development and functioning and induces cognitive impairments in the young adult offspring.

Developmental vitamin D deficiency alters dopamine-mediated behaviors and dopamine transporter function in adult female rats

RATIONALE

Developmental vitamin D (DVD) deficiency has been proposed as a risk factor for schizophrenia. DVD deficiency in neonatal rats is associated with alterations in cellular development, dopamine metabolism, and brain morphology. DVD-deficient adult rats show novelty-induced hyperlocomotion and an enhanced locomotor response to MK-801, which can be ameliorated by pretreatment with the antipsychotic drug haloperidol.

OBJECTIVES

In this study, we examined locomotor responses of male and female juvenile and adult rats to a dose range of amphetamine. We also measured dopamine receptor and monoamine transporter densities in adult brain.

RESULTS

Female DVD-deficient adult rats displayed an enhanced sensitivity to amphetamine-induced locomotion, an increased dopamine transporter density in the caudate-putamen and increased affinity in the nucleus accumbens compared with control females. By contrast, there were no differences between control and DVD-deficient male rats.

DISCUSSION

Taken together, this suggests an alteration in the development of the dopamine system and on dopamine-mediated behaviors in female DVD-deficient rats, and this may be relevant to the underlying neurobiology of schizophrenia.

Models of neurodevelopmental abnormalities in schizophrenia

The neurodevelopmental hypothesis of schizophrenia asserts that the underlying pathology of schizophrenia has its roots in brain development and that these brain abnormalities do not manifest themselves until adolescence or early adulthood. Animal models based on developmental manipulations have provided insight into the vulnerability of the developing fetus and the importance of the early environment for normal maturation. These models have provided a wide range of validated approaches to answer questions regarding environmental influences on both neural and behavioral development. In an effort to better understand the developmental hypothesis of schizophrenia, animal models have been developed, which seek to model the etiology and/or the pathophysiology of schizophrenia or specific behaviors associated with the disease. Developmental models specific to schizophrenia have focused on epidemiological risk factors (e.g., prenatal viral insult, birth complications) or more heuristic models aimed at understanding the developmental neuropathology of the disease (e.g., ventral hippocampal lesions). The combined approach of behavioral and neuroanatomical evaluation of these models strengthens their utility in improving our understanding of the pathophysiology of schizophrenia and developing new treatment strategies.

Vitamin D, a neuro-immunomodulator: implications for neurodegenerative and autoimmune diseases

It has been known for more than 20 years that vitamin D exerts marked effects on immune and neural cells. These non-classical actions of vitamin D have recently gained a renewed attention since it has been shown that diminished levels of vitamin D induce immune-mediated symptoms in animal models of autoimmune diseases and is a risk factor for various brain diseases. For example, it has been demonstrated that vitamin D (i) modulates the production of several neurotrophins, (ii) up-regulates Interleukin-4 and (iii) inhibits the differentiation and survival of dendritic cells, resulting in impaired allo-reactive T cell activation. Not surprisingly, vitamin D has been found to be a strong candidate risk-modifying factor for Multiple Sclerosis (MS), the most prevalent neurological and inflammatory disease in the young adult population. Vitamin D is a seco-steroid hormone, produced photochemically in the animal epidermis. The action of ultraviolet light (UVB) on 7-dehydrocholesterol results in the production of pre-vitamin D which, after thermo-conversion and two separate hydroxylations, gives rise to the active 1,25-dihydroxyvitamin D. Vitamin D acts through two types of receptors: (i) the vitamin D receptor (VDR), a member of the steroid/thyroid hormone superfamily of transcription factors, and (ii) the MARRS (membrane associated, rapid response steroid binding) receptor, also known as Erp57/Grp58. In this article, we review some of the mechanisms that may underlie the role of vitamin D in various brain diseases. We then assess how vitamin D imbalance may lay the foundation for a range of adult disorders, including brain pathologies (Parkinson's disease, epilepsy, depression) and immune-mediated disorders (rheumatoid arthritis, type I diabetes mellitus, systemic lupus erythematosus or inflammatory bowel diseases). Multidisciplinary scientific collaborations are now required to fully appreciate the complex role of vitamin D in mammal metabolism.

Transient prenatal vitamin D deficiency is associated with changes of synaptic plasticity in the dentate gyrus in adult rats

Transient prenatal vitamin D deficiency is considered a neurodevelopmental animal model in schizophrenia research. Vitamin D deficiency in female rats causes morphological, cellular and molecular changes in the brain and alters behaviour and nerve growth factors expression in their offspring. Prenatal depleted animals showed a significant impairment of latent inhibition, a feature often associated with schizophrenia and of hole board habituation. Interestingly, memory consolidation of brightness discrimination was improved. Possible functional effects of altered brain development that results from prenatal vitamin D deficiency were characterized by investigation of potentiation phenomena in the hippocampus in freely moving rats. Transient prenatal vitamin D deficiency induced an enhancement of long-term potentiation (LTP) using either weak tetanic or strong tetanic stimulation, whereas the response to test stimuli was not changed. The classic neuroleptic drug haloperidol (Hal) and the atypical neuroleptic risperidone (Ris) in doses, which normalized behavioural disturbances in prenatal vitamin D-deficient animals without any side effects on the normal behaviour decreased the enhanced LTP in the experimental group to control level. Interestingly, the effect of the substances was different in experimental and control rats. The LTP was enhanced in control animals by the low doses of the drugs effective in our behavioural experiments. It can be suggested, that changes in brain development induced by prenatal vitamin D deficiency lead to specific functional alterations in hippocampal synaptic plasticity. LTP is considered a cellular correlate of learning and memory. The better retention performance in brightness discrimination seems in accordance with enhanced potentiation level.

Developmental vitamin D deficiency causes abnormal brain development

There is now clear evidence that vitamin D is involved in brain development. Our group is interested in environmental factors that shape brain development and how this may be relevant to neuropsychiatric diseases including schizophrenia. The origins of schizophrenia are considered developmental. We hypothesised that developmental vitamin D (DVD) deficiency may be the plausible neurobiological explanation for several important epidemiological correlates of schizophrenia namely: (1) the excess winter/spring birth rate, (2) increased incidence of the disease in 2nd generation Afro-Caribbean migrants and (3) increased urban birth rate. Moreover we have published two pieces of direct epidemiological support for this hypothesis in patients. In order to establish the "Biological Plausibility" of this hypothesis we have developed an animal model to study the effect of DVD deficiency on brain development. We do this by removing vitamin D from the diet of female rats prior to breeding. At birth we return all dams to a vitamin D containing diet. Using this procedure we impose a transient, gestational vitamin D deficiency, while maintaining normal calcium levels throughout. The brains of offspring from DVD-deficient dams are characterised by (1) a mild distortion in brain shape, (2) increased lateral ventricle volumes, (3) reduced differentiation and (4) diminished expression of neurotrophic factors. As adults, the alterations in ventricular volume persist and alterations in brain gene and protein expression emerge. Adult DVD-deficient rats also display behavioural sensitivity to agents that induce psychosis (the NMDA antagonist MK-801) and have impairments in attentional processing. In this review we summarise the literature addressing the function of vitamin D on neuronal and non-neuronal cells as well as in vivo results from DVD-deficient animals. Our conclusions from these data are that vitamin D is a plausible biological risk factor for neuropsychiatric disorders and that vitamin D acts as a neurosteroid with direct effects on brain development.

Vitamin D and the occurrence of depression: causal association or circumstantial evidence?

While recent laboratory-based studies have substantially advanced our understanding of the action of vitamin D in the brain, much is still unknown concerning how vitamin D relates to mood. The few epidemiological studies of vitamin D and depression have produced inconsistent results and generally have had substantial methodological limitations. Recent findings from a randomized trial suggest that high doses of supplemental vitamin D may improve mild depressive symptoms, but important questions persist concerning how vitamin D may affect monoamine function and hypothalamic-pituitary-adrenal axis response to stress, whether vitamin D supplementation can improve mood in individuals with moderate-to-severe depression, and whether vitamin D sufficiency is protective against incident depression and recurrence. At this time, it is premature to conclude that vitamin D status is related to the occurrence of depression. Additional prospective studies of this relationship are essential.

Season of birth and not vitamin D receptor promoter polymorphisms is a risk factor for multiple sclerosis

Both genetic and environmental factors contribute to multiple sclerosis, the most common neurodegenerative disorder with onset in young adults. The objective of the current study is, based on the hypothesis that environmentally predisposed individuals are at risk for multiple sclerosis, to investigate whether they also carry genetic variants within the vitamin D machinery. Using medical files and DNA samples from 583 trios (a patient and both parents) of the French Multiple Sclerosis Genetics Group as well as data from the French Statistics Bureau, we aimed to assess whether: (1) a seasonality of birth was observed in French multiple sclerosis patients; (2) three single nucleotide polymorphisms within the promoter region of the vitamin D receptor were associated with multiple sclerosis susceptibility; and (3) the combination of a high risk month of birth and vitamin D receptor polymorphisms were correlated to multiple sclerosis incidence. We observed a significantly reduced number of individuals born in November who were later diagnosed as multiple sclerosis patients. However, we found no association between the three studied vitamin D receptor polymorphisms and multiple sclerosis. In conclusion, our data suggest that high levels of vitamin D during the third trimester of pregnancy could be a protective factor for multiple sclerosis.

Vitamin D deficiency during pregnancy may impair maternal and fetal outcomes

Over the past decade, new evidence has shown that vitamin D deficiency may contribute to the risk of developing a wide range of common chronic diseases that are different from the classic action on calcium and bone homeostasis. Acting through the vitamin D receptor, vitamin D can produce a wide array of favorable biological effects via genomic, non-genomic or intracrine mechanisms and, therefore, contributes to the improvement of human health in humans. We hypothesize that some of these effects may be even more critical during pregnancy. The focus of this paper is to review the data on the classic and non-classic actions of vitamin D with regards to pregnancy. It appears that vitamin D insufficiency during pregnancy is potentially associated with increased risk of preeclampsia, insulin resistance and gestational diabetes mellitus. Furthermore, experimental data also anticipate that vitamin D sufficiency is critical for fetal development, and especially for fetal brain development and immunological functions. Vitamin D deficiency during pregnancy may, therefore, not only impair maternal skeletal preservation and fetal skeletal formation but also be vital to the fetal "imprinting" that may affect chronic disease susceptibility soon after birth as well as later in life.

Premature aging in vitamin D receptor mutant mice

Hypervitaminosis vitamin D(3) has been recently implicated in premature aging through the regulation of 1alpha hydroxylase expression by klotho and fibroblast growth factor-23 (Fgf-23). Here we examined whether the lack of hormonal function of vitamin D(3) in mice is linked to aging phenomena. For this, we used vitamin D(3) receptor (VDR) "Tokyo" knockout (KO) mice (fed with a special rescue diet) and analyzed their growth, skin and cerebellar morphology, as well as overall motor performance. We also studied the expression of aging-related genes, such as Fgf-23, nuclear factor kappaB (NF-kappaB), p53, insulin like growth factor 1 (IGF1) and IGF1 receptor (IGF1R), in liver, as well as klotho in liver, kidney and prostate tissues. Overall, VDR KO mice showed several aging related phenotypes, including poorer survival, early alopecia, thickened skin, enlarged sebaceous glands and development of epidermal cysts. There was no difference either in the structure of cerebellum or in the number of Purkinje cells. Unlike the wildtype controls, VDR KO mice lose their ability to swim after 6 months of age. Expression of all the genes was lower in old VDR KO mice, but only NF-kappaB, Fgf-23, p53 and IGF1R were significantly lower. Since the phenotype of aged VDR knockout mice is similar to mouse models with hypervitaminosis D(3), our study suggests that VDR genetic ablation promotes premature aging in mice, and that vitamin D(3) homeostasis regulates physiological aging.

Why schizophrenia epidemiology needs neurobiology--and vice versa

Schizophrenia epidemiology can provide us with valuable information to guide research directions. However, while epidemiology is useful for generating candidate risk factors, it can not always deliver studies that prove causality. We argue that the field needs more translational research that links schizophrenia epidemiology with molecular, cellular, and behavioral neuroscience. Cross-disciplinary projects related to candidate genetic or nongenetic risk factors not only can address the biological plausibility of these factors, but they can serve as catalysts for discovery in neuroscience. This type of cross disciplinary research is likely to be more efficient compared to clinically dislocated basic neuroscience. Examples of this type of translational research are provided based on (a) the impact of prenatal nutrition and prenatal infection on brain development and (b) understanding the causes and consequences of agenesis of the corpus callosum. We need to build shared discovery platforms that encourage greater cross-fertilization between schizophrenia epidemiology and basic neuroscience research.

Vitamin D3 signalling in the brain enhances the function of phosphoprotein enriched in astrocytes--15 kD (PEA-15)

In spite of growing evidence linking vitamin D₃ levels to mental health disorders, little is known about its direct targets in the brain. This study set out to investigate targets of vitamin D₃ in a human brain stem cell line. We employed arrays with antibodies directed against more than 600 structural and signalling proteins, including phospho-variants. Over 180 proteins responded to vitamin D₃, such as cyclin-dependent protein-serine kinase 1/2, epidermal growth factor receptor-tyrosine kinase, protein kinase A, protein-serine kinase Bγ and protein-serine kinase Cα. PEA-15 (phosphoprotein enriched in astrocytes-15 kD, also known as PED), known to be involved in various anti-proliferative and anti-apoptotic effects, was strongly up-regulated. In silico promoter analysis revealed conserved binding sites for vitamin D₃ receptor, suggesting a strong vitamin D₃ dependency of the PEA-15 promoter. PEA-15 up-regulation by vitamin D₃ could be confirmed by Western blot in two different cell lines. Analysis of mRNA and protein phosphorylation status of PEA-15 suggests that increased PEA-15 promoter activity and increased protein stabilization contribute to the overall rise of PEA-15 protein. In a functional test of this novel pathway, we demonstrated that vitamin D₃ was able to rescue cells from TRAIL-induced apoptosis through regulation of the PEA-15 expression and function. Summarized, our study presents novel targets of vitamin D₃ relevant for apoptosis and cell proliferation, and thus strongly supports a function of vitamin D₃ in the brain that impacts on processes highly relevant for major neurological disorders.

Gestational vitamin D deficiency: long-term effects on the brain

Gestational vitamin D deficiency causes permanent changes in the developing rat brain. Not only does it alter brain gene and protein expression, deficiency disrupts the balance between neuronal stem cell proliferation and programmed cell death in the offspring. These data are particularly relevant in light of new work showing a high prevalence of vitamin D deficiency in humans.

Vitamin D2 potentiates axon regeneration

To date, the use of autograft tissue remains the "gold standard" technique for repairing transected peripheral nerves. However, the recovery is suboptimal, and neuroactive molecules are required. In the current study, we focused our attention on vitamin D, an FDA-approved molecule whose neuroprotective and neurotrophic actions are increasingly recognized. We assessed the therapeutic potential of ergocalciferol--the plant-derived form of vitamin D, named vitamin D2--in a rat model of peripheral nerve injury and repair. The left peroneal nerve was cut out on a length of 10 mm and immediately autografted in an inverted position. After surgery, animals were treated with ergocalciferol (100 IU/kg/day) and compared to untreated animals. Functional recovery of hindlimb was measured weekly, during 10 weeks post-surgery, using a walking track apparatus and a numerical camcorder. At the end of this period, motor and sensitive responses of the regenerated axons were calculated and histological analysis was performed. We observed that vitamin D2 significantly (i) increased axogenesis and axon diameter; (ii) improved the responses of sensory neurons to metabolites such as KCl and lactic acid; and (iii) induced a fast-to-slow fiber type transition of the Tibialis anterior muscle. In addition, functional recovery was not impaired by vitamin D supplementation. Altogether, these data indicate that vitamin D potentiates axon regeneration. Pharmacological studies with various concentrations of the two forms of vitamin D (ergocalciferol vs. cholecalciferol) are now required before recommending this molecule as a potential supplemental therapeutic approach following nerve injury.

Vitamin D and human health: lessons from vitamin D receptor null mice

The vitamin D endocrine system is essential for calcium and bone homeostasis. The precise mode of action and the full spectrum of activities of the vitamin D hormone, 1,25-dihydroxyvitamin D [1,25-(OH)(2)D], can now be better evaluated by critical analysis of mice with engineered deletion of the vitamin D receptor (VDR). Absence of a functional VDR or the key activating enzyme, 25-OHD-1alpha-hydroxylase (CYP27B1), in mice creates a bone and growth plate phenotype that mimics humans with the same congenital disease or severe vitamin D deficiency. The intestine is the key target for the VDR because high calcium intake, or selective VDR rescue in the intestine, restores a normal bone and growth plate phenotype. The VDR is nearly ubiquitously expressed, and almost all cells respond to 1,25-(OH)(2)D exposure; about 3% of the mouse or human genome is regulated, directly and/or indirectly, by the vitamin D endocrine system, suggesting a more widespread function. VDR-deficient mice, but not vitamin D- or 1alpha-hydroxylase-deficient mice, and man develop total alopecia, indicating that the function of the VDR and its ligand is not fully overlapping. The immune system of VDR- or vitamin D-deficient mice is grossly normal but shows increased sensitivity to autoimmune diseases such as inflammatory bowel disease or type 1 diabetes after exposure to predisposing factors. VDR-deficient mice do not have a spontaneous increase in cancer but are more prone to oncogene- or chemocarcinogen-induced tumors. They also develop high renin hypertension, cardiac hypertrophy, and increased thrombogenicity. Vitamin D deficiency in humans is associated with increased prevalence of diseases, as predicted by the VDR null phenotype. Prospective vitamin D supplementation studies with multiple noncalcemic endpoints are needed to define the benefits of an optimal vitamin D status.

Driving GDNF expression: the green and the red traffic lights

Glial cell line-derived neurotrophic factor (GDNF) is widely recognized as a potent survival factor for dopaminergic neurons of the nigrostriatal pathway that degenerate in Parkinson's disease (PD). In animal models of PD, GDNF delivery to the striatum or the substantia nigra protects dopaminergic neurons against subsequent toxin-induced injury and rescues previously damaged neurons, promoting recovery of the motor function. Thus, GDNF was proposed as a potential therapy to PD aimed at slowing down, halting or reversing neurodegeneration, an issue addressed in previous reviews. However, the use of GDNF as a therapeutic agent for PD is hampered by the difficulty in delivering it to the brain. Another potential strategy is to stimulate the endogenous expression of GDNF, but in order to do that we need to understand how GDNF expression is regulated. The aim of this review is to do a comprehensive analysis of the state of the art on the control of endogenous GDNF expression in the nervous system, focusing mainly on the nigrostriatal pathway. We address the control of GDNF expression during development, in the adult brain and after injury, and how damaged neurons signal glial cells to up-regulate GDNF. Pharmacological agents or natural molecules that increase GDNF expression and show neuroprotective activity in animal models of PD are reviewed. We also provide an integrated overview of the signalling pathways linking receptors for these molecules to the induction of GDNF gene, which might also become targets for neuroprotective therapies in PD.

Protein expression in the nucleus accumbens of rats exposed to developmental vitamin D deficiency

INTRODUCTION

Developmental vitamin D (DVD) deficiency is a candidate risk factor for schizophrenia. Animal models have confirmed that DVD deficiency is associated with a range of altered genomic, proteomic, structural and behavioural outcomes in the rat. Because the nucleus accumbens has been implicated in neuropsychiatric disorders, in the current study we examined protein expression in this region in adult rats exposed to DVD deficiency

METHODS

Female Sprague Dawley rats were maintained on a vitamin D deficient diet for 6 weeks, mated and allowed to give birth, after which a diet containing vitamin D was reintroduced. Male adult offspring (n = 8) were compared to control male (n = 8). 2-D gel electrophoresis-based proteomics and mass spectroscopy were used to investigate differential protein expression.

RESULTS

There were 35 spots, mapped to 33 unique proteins, which were significantly different between the two groups. Of these, 22 were down-regulated and 13 up-regulated. The fold changes were uniformly small, with the largest FC being -1.67. Within the significantly different spots, three calcium binding proteins (calbindin1, calbindin2 and hippocalcin) were altered. Other proteins associated with DVD deficiency related to mitochondrial function, and the dynamin-like proteins.

CONCLUSIONS

Developmental vitamin D deficiency was associated with subtle changes in protein expression in the nucleus accumbens. Disruptions in pathways related to calcium-binding proteins and mitochondrial function may underlie some of the behavioural features associated with animal models of developmental vitamin D deficiency.

Co-expression of CYP27B1 enzyme with the 1.5kb CYP27B1 promoter-luciferase transgene in the mouse

The renal enzyme 25-hydroxyvitamin D 1alpha-hydroxylase (CYP27B1), responsible for the synthesis of circulating. 1,25-dihydroxyvitamin D (1,25D), is also expressed in a number of non-renal tissues. The regulation of CYP27B1 expression by the short flanking promoter outside the kidney is, however, largely unknown. We have used a transgenic mice expressing the 1.5kb promoter of the human CYP27B1 gene fused to the firefly luciferase gene in order to investigate tissue-specific CYP27B1 expression. These transgenic animals demonstrated co-localised luciferase and endogenous CYP27B1 expression in kidney proximal convoluted tubular cells. Strong co-expression of luciferase and CYP27B1 also occurred in neurons and Purkinje cells of the cerebellum and in Leydig and Sertoli cells of the testes. Other tissues to exhibit CYP27B1-promoter directed luciferase activity included lung, prostate, trabecular bone and jejunum as well as the choroid epithelium. The tissue specific changes in luciferase activity were age-related. These findings demonstrate that the proximal 1.5kb 5' flanking region of the CYP27B1 gene directs the expression of CYP27B1 in a number of known and novel tissues in a specific manner.

Diagnosis and treatment of vitamin D deficiency

The recent discovery--in a randomised, controlled trial--that daily ingestion of 1100 IU of colecalciferol (vitamin D) over a 4-year period dramatically reduced the incidence of non-skin cancers makes it difficult to overstate the potential medical, social and economic implications of treating vitamin D deficiency. Not only are such deficiencies common, probably the rule, vitamin D deficiency stands implicated in a host of diseases other than cancer. The metabolic product of vitamin D is a potent, pleiotropic, repair and maintenance, secosteroid hormone that targets > 200 human genes in a wide variety of tissues, meaning it has as many mechanisms of action as genes it targets. A common misconception is that government agencies designed present intake recommendations to prevent or treat vitamin D deficiency. They did not. Instead, they are guidelines to prevent particular metabolic bone diseases. Official recommendations were never designed and are not effective in preventing or treating vitamin D deficiency and in no way limit the freedom of the physician--or responsibility--to do so. At this time, assessing serum 25-hydroxy-vitamin D is the only way to make the diagnosis and to assure that treatment is adequate and safe. The authors believe that treatment should be sufficient to maintain levels found in humans living naturally in a sun-rich environment, that is, > 40 ng/ml, year around. Three treatment modalities exist: sunlight, artificial ultraviolet B radiation or supplementation. All treatment modalities have their potential risks and benefits. Benefits of all treatment modalities outweigh potential risks and greatly outweigh the risk of no treatment. As a prolonged 'vitamin D winter', centred on the winter solstice, occurs at many temperate latitudes, < or = 5000 IU (125 microg) of vitamin D/day may be required in obese, aged and/or dark-skinned patients to maintain adequate levels during the winter, a dose that makes many physicians uncomfortable.

Is there convincing biological or behavioral evidence linking vitamin D deficiency to brain dysfunction?

Vitamin D insufficiency is common in the United States; the elderly and African-Americans are at particularly high risk of deficiency. This review, written for a broad scientific readership, presents a critical overview of scientific evidence relevant to a possible causal relationship between vitamin D deficiency and adverse cognitive or behavioral effects. Topics discussed are 1) biological functions of vitamin D relevant to cognition and behavior; 2) studies in humans and rodents that directly examine effects of vitamin D inadequacy on cognition or behavior; and 3) immunomodulatory activity of vitamin D relative to the proinflammatory cytokine theory of cognitive/behavioral dysfunction. We conclude there is ample biological evidence to suggest an important role for vitamin D in brain development and function. However, direct effects of vitamin D inadequacy on cognition/behavior in human or rodent systems appear to be subtle, and in our opinion, the current experimental evidence base does not yet fully satisfy causal criteria. Possible explanations for the apparent inconsistency between results of biological and cognitive/behavioral experiments, as well as suggested areas for further research are discussed. Despite residual uncertainty, recommendations for vitamin D supplementation of at-risk groups, including nursing infants, the elderly, and African-Americans appear warranted to ensure adequacy.

Autism and vitamin D

Any theory of autism's etiology must take into account its strong genetic basis while explaining its striking epidemiology. The apparent increase in the prevalence of autism over the last 20 years corresponds with increasing medical advice to avoid the sun, advice that has probably lowered vitamin D levels and would theoretically greatly lower activated vitamin D (calcitriol) levels in developing brains. Animal data has repeatedly shown that severe vitamin D deficiency during gestation dysregulates dozens of proteins involved in brain development and leads to rat pups with increased brain size and enlarged ventricles, abnormalities similar to those found in autistic children. Children with the Williams Syndrome, who can have greatly elevated calcitriol levels in early infancy, usually have phenotypes that are the opposite of autism. Children with vitamin D deficient rickets have several autistic markers that apparently disappear with high-dose vitamin D treatment. Estrogen and testosterone have very different effects on calcitriol's metabolism, differences that may explain the striking male/female sex ratios in autism. Calcitriol down-regulates production of inflammatory cytokines in the brain, cytokines that have been associated with autism. Consumption of vitamin D containing fish during pregnancy reduces autistic symptoms in offspring. Autism is more common in areas of impaired UVB penetration such as poleward latitudes, urban areas, areas with high air pollution, and areas of high precipitation. Autism is more common in dark-skinned persons and severe maternal vitamin D deficiency is exceptionally common the dark-skinned.

CONCLUSION

simple Gaussian distributions of the enzyme that activates neural calcitriol combined with widespread gestational and/or early childhood vitamin D deficiency may explain both the genetics and epidemiology of autism. If so, much of the disease is iatrogenic, brought on by medical advice to avoid the sun. Several types of studies could easily test the theory.

No association between serum 25-hydroxyvitamin D3 level and performance on psychometric tests in NHANES III

BACKGROUND

Animal studies and in vitro experiments indicate that vitamin D is involved in a diverse range of neurobiological functions. We had the opportunity to examine the relationship between serum 25-hydroxyvitamin D(3) [25(OH)D] levels and performance on various cognitive tasks, based on a large, representative community sample.

METHODS

Three age groups were available from the population-based NHANES III survey: adolescent group (n = 1,676, age range 12-17 years), adult group (n = 4,747, 20-60 years), elderly group (n = 4,809, 60-90 years). The associations between eight psychometric measures and serum 25(OH)D were assessed.

RESULTS

In the adolescent and adult groups, none of the psychometric measures were associated with 25(OH)D levels. In the elderly group there was a significant difference between 25(OH)D quintiles performance on a learning and memory task; however, those with the highest quintile of 25(OH)D were most impaired on the task, contrary to the hypotheses.

CONCLUSION

Lower 25(OH)D levels were not associated with impaired performance on various psychometric measures. While it remains to be seen if chronic exposure to low 25(OH)D levels alters brain function in the long term, this cross-sectional study suggests that 25(OH)D levels do not influence neurocognitive performance.

Hyperthermia in utero due to maternal influenza is an environmental risk factor for schizophrenia

A hypothesis is presented that the association between maternal influenza and other causes of fever during the second trimester of pregnancy and the subsequent development of schizophrenia in the child is due to the damage caused by hyperthermia to the developing amygdalohippocampal complex and associated structures in the fetal brain. Hyperthermia is a known cause of congenital defects of the central nervous system and other organs after sufficiently severe exposures during early organogenesis. The pathogenic mechanisms include death of actively dividing neuroblasts, disruption of cell migration and arborization and vascular damage. In experimental studies, hyperthermia during later stages of central nervous system development also caused damage to the developing brainstem that was associated with functional defects. This damage usually results in hypoplasia of the parts undergoing active development at the time of exposure. Recent studies have shown no evidence of direct invasion of the fetus by the influenza virus. Factors that might interact with hyperthermia include familial liability to schizophrenia, season of birth, maternal nutrition, severe stress and medications used to alleviate the symptoms of fevers. The time of the development of the fetal amygdalohippocampal complex and the changes found in its structure and associated areas of the brain are compatible with the known effects of hyperthermia.

Developmental vitamin D deficiency alters brain protein expression in the adult rat: implications for neuropsychiatric disorders

An increased risk for multiple sclerosis and schizophrenia is observed at increasing latitude and in patients born in winter or spring. To explore a possible link between maternal vitamin D deficiency and these brain disorders, we examined the impact of prenatal hypovitaminosis D on protein expression in the adult rat brain. Vitamin D-deficient female rats were mated with vitamin D normal males. Pregnant females were kept vitamin D-deficient until birth whereupon they were returned to a control diet. At week 10, protein expression in the progeny's prefrontal cortex and hippocampus was compared with control animals using silver staining 2-D gels associated with MS and newly devised data mining software. Developmental vitamin D (DVD) deficiency caused a dysregulation of 36 brain proteins involved in several biological pathways including oxidative phosphorylation, redox balance, cytoskeleton maintenance, calcium homeostasis, chaperoning, PTMs, synaptic plasticity and neurotransmission. A computational analysis of these data revealed that (i) nearly half of the molecules dysregulated in our animal model have also been shown to be misexpressed in either schizophrenia and/or multiple sclerosis and (ii) an impaired synaptic network may be a consequence of mitochondrial dysfunction.

Vitamin D deficiency during various stages of pregnancy in the rat; its impact on development and behaviour in adult offspring

Developmental vitamin D (DVD) deficiency alters brain development and behaviour in the rat. The aim of this study was to vary levels of vitamin D deficiency during gestation and examine the effects on developmental milestones and behaviour in adult offspring. By manipulating the withdrawal and reintroduction of vitamin D in the diet of female Sprague-Dawley rats, their offspring were subjected to four different prenatal vitamin D conditions: (a) control (normal vitamin D throughout gestation); (b) early-DVD deficiency; (c) late-DVD deficiency; and (d) full-DVD deficiency. We show that the standard measure for vitamin D status, 25(OH)D(3), can be significantly manipulated within 7 days by dietary intervention. We also show that levels of the active form of this vitamin, 1,25(OH)(2)D(3), replete within the same time frame as 25(OH)D(3) but are slower to deplete. Developmental milestones remained normal across all four dietary groups. Concerning the adult behavioural phenotype, both full- and late-DVD deficiency were associated with MK-801-induced hyperlocomotion. Overall, these data suggest that vitamin D deficiency restricted to late gestation only is sufficient to disrupt adult brain functioning in the rat. These findings suggest there may be a therapeutic window for maternal dietary intervention in the DVD model of psychosis.

Maternal vitamin D depletion alters neurogenesis in the developing rat brain

Evidence is accumulating that normal levels of vitamin D are important for brain development. Vitamin D acts as an anti-proliferative agent in a wide variety of tissues and developmental vitamin D (DVD) deficiency has been shown to alter brain structure and function. The aim of this study was to investigate the effect of DVD deficiency on neuroprogenitor formation in the neonatal brain. We show that DVD deficiency increased the number of neurospheres formed in cultures from the neonatal subventricular zone. Exogenous vitamin D added to the culture medium reduced neurosphere number in control but not DVD cultures. We show the receptor for vitamin D is concentrated in the subventricular zone and is also present in cultured neurospheres prepared from this region. These results show that vitamin D can regulate cell proliferation in the developing brain. Further studies are warranted to examine the underlying mechanisms for these findings.

Developmental vitamin D deficiency alters the expression of genes encoding mitochondrial, cytoskeletal and synaptic proteins in the adult rat brain

Epidemiology has highlighted the links between season of birth, latitude and the prevalence of brain disorders such as multiple sclerosis and schizophrenia. In line with these data, we have hypothesized that "imprinting" with low prenatal vitamin D could contribute to the risk of these two brain disorders. Previously, we have shown that transient developmental hypovitaminosis D induces permanent changes in adult nervous system. The aim of this study was to examine the impact of prenatal hypovitaminosis D on gene expression in the adult rat brain. Vitamin D deficient female rats were mated with undeprived males and the offspring were fed with a control diet after birth. At Week 10, gene expression in the progeny's brain was compared with control animals using Affymetrix gene microarrays. Prenatal hypovitaminosis D causes a dramatic dysregulation of several biological pathways including oxidative phosphorylation, redox balance, cytoskeleton maintenance, calcium homeostasis, chaperoning, post-translational modifications, synaptic plasticity and neurotransmission. A computational analysis of these data suggests that impaired synaptic network may be a consequence of mitochondrial dysfunction. Since disruptions of mitochondrial metabolism have been associated with both multiple sclerosis and schizophrenia, developmental vitamin D deficiency may be a heuristic animal model for the study of these two brain diseases.

Vitamin D: the secosteroid hormone and human reproduction

Vitamin D is a secosteroid with an endocrine mechanism of action which is sequentially synthesized in humans in the skin, liver and kidneys. The active hormone, 1alpha,25-dihydrocholecalciferol [1,25(OH)2D3], is often considered only in terms of its role in controlling calcium and phosphorus homeostasis. However, cumulative evidence points to the presence of vitamin D receptors in many tissues. The present article summarizes key points regarding the participation of vitamin D in pregnancy and breastfeeding. During pregnancy, sufficient vitamin D concentrations are needed not only to address the growing demand for calcium on the part of the fetus, but also to participate in fetal growth, development of the nervous system, lung maturation and fetal immune system function. Hypovitaminosis D has been related to the development of diabetes, pre-eclampsia and fetal neurological disorders. During pregnancy and lactation, calcium from the maternal skeleton is mobilized, with a rise in bone turnover and a reduction in bone mass. It is advisable for pregnant and nursing women to maintain adequate levels of vitamin D, through small doses of solar exposure to facilitate natural formation of the hormone or by ingesting appropriate vitamin supplements. Further studies are needed to clarify the many gaps in knowledge and elucidate the role of vitamin D in the context of reproduction. Confirmation of experimental observations relating to the risks of hypovitaminosis D would have important public health implications.

Neurosteroid hormone vitamin D and its utility in clinical nutrition

PURPOSE OF REVIEW

Vitamin D is a seco-steroid hormone with multiple functions in the nervous system. We discuss clinical and experimental evidence of the role of vitamin D in normal and pathological brain functions, and analyze the relative importance of vitamin D-modulated brain mechanisms at different stages of life. We also outline perspectives for the use of vitamin D in clinical nutrition to prevent or treat various brain disorders.

RECENT FINDINGS

Numerous brain dysfunctions are linked to vitamin D deficits and/or dysfunctions of its receptors. In both animals and humans, vitamin D serves as an important endogenous and/or exogenous regulator of neuroprotection, antiepileptic and anticalcification effects, neuro-immunomodulation, interplay with neurotransmitters and hormones, modulation of behaviors, brain ageing, and some other, less-explored, brain processes.

SUMMARY

Vitamin D emerges as an important neurosteroid hormone in the brain, with a strong potential for age-specific applications in clinical nutrition.

Developmental vitamin D deficiency alters MK 801-induced hyperlocomotion in the adult rat: An animal model of schizophrenia

BACKGROUND

Developmental vitamin D (DVD) deficiency has been proposed as a risk factor for schizophrenia. The behavioral phenotype of adult rats subjected to transient low prenatal vitamin D is characterized by spontaneous hyperlocomotion but normal prepulse inhibition of acoustic startle (PPI). The aim of this study was to examine the impact of selected psychotropic agents and one well-known antipsychotic agent on the behavioral phenotype of DVD deplete rats.

METHODS

Control versus DVD deplete adult rats were assessed on holeboard, open field and PPI. In the open field, animals were given MK-801 and/or haloperidol. For PPI, the animals were given apomorphine or MK-801.

RESULTS

DVD deplete rats had increased baseline locomotion on the holeboard task and increased locomotion in response to MK-801 compared to control rats. At low doses, haloperidol antagonized the MK-801 hyperactivity of DVD deplete rats preferentially and, at a high dose, resulted in a more pronounced reduction in spontaneous locomotion in DVD deplete rats. DVD depletion did not affect either baseline or drug-mediated PPI response.

CONCLUSIONS

These results suggest that DVD deficiency is associated with a persistent alteration in neuronal systems associated with motor function but not those associated with sensory motor gating. In light of the putative association between low prenatal vitamin D and schizophrenia, the discrete behavioral differences associated with the DVD model may help elucidate the neurobiological correlates of schizophrenia.

Behavioural anomalies in mice evoked by “Tokyo” disruption of the Vitamin D receptor gene

Vitamin D is a steroid hormone with many important functions in the brain, mediated through the nuclear Vitamin D receptor (VDR). Mounting clinical data link VDR mutations to various psychiatric phenotypes. We have reported previously that mutant mice lacking functional VDR ("Tokyo" VDR mutant mice) display several behavioural anomalies, including high anxiety and aberrant grooming. Given the important role of Vitamin D and VDR in brain development and functioning, we hypothesized that several other important behavioural domains may be affected by disruption of the VDR gene in mice. Here we report that VDR mutants display unaffected depressive-like behaviour, but show abnormal social behaviours, reduced social barbering and aggressiveness, impaired nest building and aberrant maternal (pup neglect, cannibalism) behaviours. Taken together, these findings confirm the important role postulated for the VDR in the regulation of behaviour, and suggest the mice lacking functional VDR may be a useful tool to model different brain disorders.

Swimming behaviour and post-swimming activity in Vitamin D receptor knockout mice

Animal experiments have shown that Vitamin D plays a role in both brain development and adult brain function. The adult Vitamin D receptor null mutant mouse (VDR -/-) is reported to be less active and more anxious than wild-type litter mate controls and to have poor swimming ability. However, an "anxious" behavioural phenotype is inferred from differences in locomotor behaviour. This is a general problem in behavioural phenotyping where a neurological phenotype is inferred from changes in locomotion which will be affected by non-neurological factors, such as muscle fatigue. In this study of VDR -/-, we conducted a detailed examination of one form of motor behaviour, swimming, compared to wildtype littermate controls. Swimming was assessed using a forced swim test, a laneway swimming test and a watermaze test using a visible platform. Post-swimming activity was assessed by comparing grooming and rearing behaviour before, and 5 min after, the forced swimming test. We replicated previous findings in which VDR -/- mice demonstrate more sinking episodes than wildtype controls in the forced swim test but they were similar to controls in the time taken to swim a 1m laneway, and in the time taken to reach a visible platform in the watermaze. Thus, the VDR -/- mice were able to swim but were not able to float. Grooming and rearing behaviour of the VDR -/- mice was similar to wildtype controls before the forced swim but the VDR -/- were much less active after the swim compared with wildtype mice which displayed high levels of grooming and rearing. We conclude that VDR -/- mice have muscular and motor impairments that do not affect their ability to swim but significantly alters the ability to float as well as their post-swimming activity. Differences in muscle strength may confound tests of activity that are used to infer an "anxious" phenotype.

Increased severity of chemically induced seizures in mice with partially deleted Vitamin D receptor gene

Vitamin D is a neuroactive steroid hormone with multiple functions in the brain. Numerous clinical and experimental data link various Vitamin D-related dysfunctions to epilepsy. Here, we study the role of Vitamin D receptors (VDRs) in experimental epilepsy in mice. To examine this problem, we assessed the seizure profiles in VDR knockout mice following a systemic injection of pentylenetetrazole (70 mg/kg). Overall, compared to the wild-type (WT) 129S1 mice (n=10 in each group), the VDR knockout group significantly demonstrated shorter latencies to the onset, higher Racine scores and increased mortality rates. Our findings suggest that VDRs modulate seizure susceptibility in mice, and that the Vitamin D/VDR endocrine system may be involved in the pathogenesis of epilepsy.

Polymorphisms in the vitamin D receptor and their associations with risk of schizophrenia and selected anthropometric measures

The association between vitamin D levels and skeletal growth has long been recognized. However, exposure to low levels of vitamin D during early life is also known to alter brain development, and is a candidate risk factor for schizophrenia. This study examines the association between four polymorphisms in the vitamin D receptor (VDR) and 1) risk of schizophrenia, and 2) three anthropometric variables (height, head size, and head shape). Four single-nucleotide polymorphisms (SNPs; rs10735810/FokI, rs1544410/BsmI, rs7975232/ApaI, and rs731236/TaqI) in the VDR gene were genotyped in 179 individuals with schizophrenia and 189 healthy controls. No significant associations were detected between any of the four VDR SNPs and risk of schizophrenia. Patients were slightly but significantly shorter compared to controls. Of the four SNPs, only rs10735810/FokI was associated with any of the anthropometric measures: the M4 isoform of this SNP was significantly associated with larger head size (P = 0.002). In light of the evidence demonstrating a role for vitamin D during brain development, the association between polymorphisms in VDR and brain development warrants closer scrutiny.