Vitamin D3 and brain development

Vitamin D, neurocognitive functioning and immunocompetence

PURPOSE OF REVIEW

Vitamin D deficiency is recognized as one of the most common medical conditions in children and adults. The major causes are inadequate sun exposure and inadequate intakes of dietary and supplemental vitamin D. Vitamin D deficiency and insufficiency defined as a 25-hydroxyvitamin D level less than 20 and 21-29 ng/ml, respectively, have been linked to increased risk for a variety of medical conditions including cancer, heart disease, type II diabetes, infectious diseases, autoimmune diseases, metabolic bone diseases and neurological disorders.

RECENT FINDINGS

The skeletal muscle and brain have a vitamin D receptor and the central nervous system has a capacity to activate vitamin D. Low vitamin D status has been linked to poor performance in neurocognitive testing in elderly. Vitamin D deficiency has been associated with muscle weakness, depression, schizophrenia, Alzheimer's disease, multiple sclerosis and a lower motor neuron-induced muscle atrophy.

SUMMARY

Correcting vitamin D deficiency and preventing vitamin D deficiency in children and adults should be a high priority for healthcare professionals to reduce risk for a wide variety of neurological disorders. Children and adults should take at least 400 international unit IU and 2000 IU vitamin D/day, respectively, to prevent vitamin D deficiency and insufficiency.

The environment and susceptibility to schizophrenia

In the present article the putative role of environmental factors in schizophrenia is reviewed and synthesized. Accumulating evidence from recent studies suggests that environmental exposures may play a more significant role in the etiopathogenesis of this disorder than previously thought. This expanding knowledge base is largely a consequence of refinements in the methodology of epidemiologic studies, including birth cohort investigations, and in preclinical research that has been inspired by the evolving literature on animal models of environmental exposures. This paper is divided into four sections. In the first, the descriptive epidemiology of schizophrenia is reviewed. This includes general studies on incidence, prevalence, and differences in these measures by urban-rural, neighborhood, migrant, and season of birth status, as well as time trends. In the second section, we discuss the contribution of environmental risk factors acting during fetal and perinatal life; these include infections [e.g. rubella, influenza, Toxoplasma gondii (T. gondii), herpes simplex virus type 2 (HSV-2)], nutritional deficiencies (e.g., famine, folic acid, iron, vitamin D), paternal age, fetal/neonatal hypoxic and other obstetric insults and complications, maternal stress and other exposures [e.g. lead, rhesus (Rh) incompatibility, maternal stress]. Other putative neurodevelopmental determinants, including cannabis, socioeconomic status, trauma, and infections during childhood and adolescence are also covered. In the third section, these findings are synthesized and their implications for prevention and uncovering biological mechanisms, including oxidative stress, apoptosis, and inflammation, are discussed. Animal models, including maternal immune activation, have yielded evidence suggesting that these exposures cause brain and behavioral phenotypes that are analogous to findings observed in patients with schizophrenia. In the final section, future studies including new, larger, and more rigorous epidemiologic investigations, and research on translational and clinical neuroscience, gene-environment interactions, epigenetics, developmental trajectories and windows of vulnerability, are elaborated upon. These studies are aimed at confirming observed risk factors, identifying new environmental exposures, elucidating developmental mechanisms, and shedding further light on genes and exposures that may not be identified in the absence of these integrated approaches. The study of environmental factors in schizophrenia may have important implications for the identification of causes and prevention of this disorder, and offers the potential to complement, and refine, existing efforts on explanatory neurodevelopmental models.

Vitamin D in health and disease: current perspectives

Despite the numerous reports of the association of vitamin D with a spectrum of development, disease treatment and health maintenance, vitamin D deficiency is common. Originating in part from the diet but with a key source resulting from transformation by exposure to sunshine, a great deal of the population suffers from vitamin D deficiency especially during winter months. It is linked to the treatment and pathogenesis and/or progression of several disorders including cancer, hypertension, multiple sclerosis, rheumatoid arthritis, osteoporosis, muscle weakness and diabetes. This widespread deficiency of Vitamin D merits consideration of widespread policies including increasing awareness among the public and healthcare professionals.

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.

Serum vitamin D concentrations are related to depression in young adult US population: the Third National Health and Nutrition Examination Survey

Background

Vitamin D receptors have been mapped throughout the brain suggesting a role for vitamin D in psychosomatic disorders. Results from previous epidemiological studies on relation between vitamin D status and depression are equivocal. Also, limited information is available relating vitamin D status with depression in young adult US population.

Methods

Data from the third National Health and Nutrition Examination Survey were used to assess association between serum vitamin D and depression in 7970 non-institutionalized US residents, aged 15-39 y. Assessment of depression was done using the Diagnostic Interview Schedule developed by the National Institute of Mental Health. After accounting for several confounding variables in multivariate logistic regression analysis, we estimated odds ratios (OR) for having depression in vitamin D deficient persons in comparison to vitamin D sufficient persons.

Results

Women, non-Hispanic blacks, persons living below poverty, persons who did not consume supplements, persons living in South and West regions and in urban areas, persons with higher BMI, and persons with current depression had higher prevalence of vitamin D deficiency compared to their counterparts. OR for having current depressive episodes in persons with serum vitamin D ≤ 50 nmol/L is significantly higher relative to those with serum vitamin D ≥ 75 nmol/L (OR = 1.85; P = 0.021).

Conclusions

In this large population based study, likelihood of having depression in persons with vitamin D deficiency is significantly higher compared to those with vitamin D sufficiency. Early diagnosis and intervention are paramount because coexistence of vitamin D deficiency and depression has serious negative consequences on health.

Developmental vitamin D (DVD) deficiency alters pup-retrieval but not isolation-induced pup ultrasonic vocalizations in the rat

Evidence from animal experiments now demonstrates that prenatal vitamin D levels influence brain development. The aims of this study were to examine isolation-induced pup ultrasonic vocalizations and maternal-infant interactions using a pup-retrieval test in developmental vitamin D (DVD) deficient and control rats. Sprague-Dawley rats were fed a vitamin D deficient diet or control diet six weeks prior to mating until birth and housed under UVB-free lighting conditions. In two separate experiments we recorded ultrasonic vocalizations at 46KHz in isolated pups and we performed a pup-retrieval test on the day of birth. There was no significant effect of maternal diet on the calling rate of isolation-induced ultrasonic vocalizations by pups. We found that DVD-deficient dams retrieved their pups sooner than control dams and engaged in more pup directed activities (sniffing and carrying pups) and had a longer latency for self-grooming and rearing than control dams. We also assessed vitamin D related measures from a terminal blood sample immediately after the pup-retrieval test and found that DVD-deficient dams and pups had significantly lower levels of 25 OH D₃, 1,25 (OH)₂D₃ and phosphate, elevated levels of parathyroid hormone (PTH) but there was no significant effect of maternal diet on calcium levels. We speculate that the altered maternal-pup interactions identified in the DVD model may impact on early periods of brain development and behaviour.

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.

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.

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.

Developmental vitamin D3 deficiency induces alterations in immune organ morphology and function in adult offspring

Vitamin D3 deficiency and insufficiency are common in women of child-bearing age. This may be cause for concern because vitamin D3 is a well known regulator of immune function and epidemiological evidence has suggested that immune disorders, including autoimmune diseases, could have developmental origins. However, it is not known whether a developmental deficiency in vitamin D3 could lead to persistent changes in the immune system in adult offspring. Given the prominence of receptors for vitamin D3 within immune cells we hypothesised that the developmental absence of vitamin D3 may alter thymic development and thus produce associated functional changes in T cells. We have developed a model of developmental vitamin D3 (DVD) deficiency in Sprague-Dawley rats, in which the vitamin D3 deficiency is transient and restricted to gestation. First we demonstrate that DVD deficiency induced an increase in central but not peripheral immune organ size. Second when stimulated, lymphocytes from DVD-deficient rats exhibit a pro-inflammatory phenotype. This is the first study to show that a transient vitamin D3 deficiency restricted to gestation can persistently alter aspects of immune phenotype and function in the adult offspring. Given an increased incidence of vitamin D3 deficiency in women of child-bearing age these findings may be highly relevant for autoimmune disorders with a developmental basis.

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.

Vitamin D and depression: where is all the sunshine?

Depression in its own right is a disabling condition impairing all aspects of human function. In persons with a chronic medical disease, depression often makes the management of chronic illness more difficult. Recently, vitamin D has been reported in the scientific and lay press as an important factor that may have significant health benefits in the prevention and the treatment of many chronic illnesses. Most individuals in this country have insufficient levels of vitamin D. This is also true for persons with depression as well as other mental disorders. Whether this is due to insufficient dietary intake, lifestyle (e.g., little outdoor exposure to sunshine), or other factors is addressed in this paper. In addition, groups at risk and suggested treatment for inadequate vitamin D levels are addressed. Effective detection and treatment of inadequate vitamin D levels in persons with depression and other mental disorders may be an easy and cost-effective therapy which could improve patients' long-term health outcomes as well as their quality of life.

Season of birth and risk for adult onset glioma

Adult onset glioma is a rare cancer which occurs more frequently in Caucasians than African Americans, and in men than women. The etiology of this disease is largely unknown. Exposure to ionizing radiation is the only well established environmental risk factor, and this factor explains only a small percentage of cases. Several recent studies have reported an association between season of birth and glioma risk. This paper reviews the plausibility of evidence focusing on the seasonal interrelation of farming, allergies, viruses, vitamin D, diet, birth weight, and handedness. To date, a convincing explanation for the occurrence of adult gliomas decades after a seasonal exposure at birth remains elusive.

Low maternal exposure to ultraviolet radiation in pregnancy, month of birth, and risk of multiple sclerosis in offspring: longitudinal analysis

OBJECTIVES

To investigate the distribution of month of birth in people with multiple sclerosis in Australia. To use the large regional and seasonal variation in ambient ultraviolet radiation in Australia to explore the association between exposure to ultraviolet radiation during pregnancy and subsequent risk of multiple sclerosis in offspring.

DESIGN

Data were gathered on birth month and year (1920-1950), sex, and state of birth for all patients surveyed in 1981 in Queensland, Western Australia, New South Wales (including Australian Capital Territory), South Australia, and Hobart (Tasmania). Population denominators were derived from the 1981 census and supplementary birth registration data. A variable for exposure to ambient ultraviolet radiation "at birth" was generated from monthly averages of daily total ambient ultraviolet radiation for each region. Negative binomial regression models were used to investigate exposure to ambient ultraviolet radiation at birth and at various intervals before birth.

SETTING

Patient data from multiple sclerosis prevalence surveys carried out in 1981; 1981 Australian census (giving the total number of people born in Australia and still alive and living in Australia in 1981 by year of birth 1920-50); supplementary Australian birth registration data covering the same birth years by month and state.

PARTICIPANTS

1524 patients with multiple sclerosis born in Australia 1920-50 from total population of 2 468 779.

MAIN OUTCOME MEASURE

Cumulative incidence rate of multiple sclerosis.

RESULTS

There was a pattern of risk of multiple sclerosis with month of birth (adjusted incidence rate ratio 1.32, 95% confidence interval 1.10 to 1.58, P<0.01, for those born in November-December compared with those born in May-June). This pattern mirrored that previously reported in the northern hemisphere. Region of birth was related to risk. After adjustment for region of birth and other factors, there was an inverse association between ambient ultraviolet radiation in the first trimester and risk of multiple sclerosis (with ≥25 erythemal (skin reddening) dose units as reference (that is, adjusted incidence rate ratio=1.00), the rates were 1.54 (1.10 to 2.16) for 20-<25 units; 1.58 (1.12 to 2.22) for 15-<20 units; 1.65 (1.17 to 2.33) for 10-<15 units; 1.65 (1.18 to 2.29) for 5-<10 units; and 1.67 (1.18 to 2.37) for <5 units). After adjustment for this exposure during early pregnancy, there was no residual association between month of birth and multiple sclerosis.

CONCLUSION

Region of birth and low maternal exposure to ultraviolet radiation in the first trimester are independently associated with subsequent risk of multiple sclerosis in offspring in Australia.

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.

Maternal pre-pregnancy obesity and risk for inattention and negative emotionality in children

OBJECTIVE

This study aimed to replicate and extend previous work showing an association between maternal pre-pregnancy adiposity and risk for attention deficit hyperactivity disorder (ADHD) symptoms in children.

METHODS

A Swedish population-based prospective pregnancy-offspring cohort was followed up when children were 5 years old (N = 1,714). Mothers and kindergarten teachers rated children's ADHD symptoms, presence and duration of problems, and emotionality. Dichotomized outcomes examined difficulties of clinical relevance (top 15% of the distribution). Analyses adjusted for pregnancy (maternal smoking, depressive symptoms, life events, education, age, family structure), birth outcomes (birth weight, gestational age, infant sex) and concurrent variables (family structure, maternal depressive symptoms, parental ADHD symptoms, and child overweight) in an attempt to rule out confounding.

RESULTS

Maternal pre-pregnancy overweight and obesity predicted high inattention symptom scores and obesity was associated with a two-fold increase in risk of difficulties with emotion intensity and emotion regulation according to teacher reports. Means of maternal ratings were unrelated to pre-pregnancy body mass index (BMI). Presence and duration of problems were associated with both maternal over and underweight according to teachers.

CONCLUSIONS

Despite discrepancies between maternal and teacher reports, these results provide further evidence that maternal pre-pregnancy overweight and obesity are associated with child inattention symptoms and extend previous work by establishing a link between obesity and emotional difficulties. Maternal adiposity at the time of conception may be instrumental in programming child mental health, as prenatal brain development depends on maternal energy supply. Possible mechanisms include disturbed maternal metabolic function. If maternal pre-pregnancy obesity is a causal risk factor, the potential for prevention is great.

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.

Traumatic brain injury and aging: is a combination of progesterone and vitamin D hormone a simple solution to a complex problem?

Although progress is being made in the development of new clinical treatments for traumatic brain injury (TBI), little is known about whether such treatments are effective in older patients, in whom frailty, prior medical conditions, altered metabolism, and changing sensitivity to medications all can affect outcomes following a brain injury. In this review we consider TBI to be a complex, highly variable, and systemic disorder that may require a new pharmacotherapeutic approach, one using combinations or cocktails of drugs to treat the many components of the injury cascade. We review some recent research on the role of vitamin D hormone and vitamin D deficiency in older subjects, and on the interactions of these factors with progesterone, the only treatment for TBI that has shown clinical effectiveness. Progesterone is now in phase III multicenter trial testing in the United States. We also discuss some of the potential mechanisms and pathways through which the combination of hormones may work, singly and in synergy, to enhance survival and recovery after TBI.

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.

25-Hydroxyvitamin D levels and cognitive performance and decline in elderly men

OBJECTIVE

To test the hypothesis that lower 25-hydroxyvitamin D [25(OH)D] levels are associated with a greater likelihood of cognitive impairment and risk of cognitive decline.

METHODS

We measured 25(OH)D and assessed cognitive function using the Modified Mini-Mental State Examination (3MS) and Trail Making Test Part B (Trails B) in a cohort of 1,604 men enrolled in the Osteoporotic Fractures in Men Study and followed them for an average of 4.6 years for changes in cognitive function.

RESULTS

In a model adjusted for age, season, and site, men with lower 25(OH)D levels seemed to have a higher odds of cognitive impairment, but the test for trend did not reach significance (impairment by 3MS: odds ratio [OR] 1.84, 95% confidence interval [CI] 0.81-4.19 for quartile [Q] 1; 1.41, 0.61-3.28 for Q2; and 1.18, 0.50-2.81 for Q3, compared with Q4 [referent group; p trend = 0.12]; and impairment by Trails B: OR 1.66, 95% CI 0.98-2.82 for Q1; 0.96, 0.54-1.69 for Q2; and 1.30, 0.76-2.22 for Q3, compared with Q4 [p trend = 0.12]). Adjustment for age and education further attenuated the relationships. There was a trend for an independent association between lower 25(OH)D levels and odds of cognitive decline by 3MS performance (multivariable OR 1.41, 95% CI 0.89-2.23 for Q1; 1.28, 0.84-1.95 for Q2; and 1.06, 0.70-1.62 for Q3, compared with Q4 [p = 0.10]), but no association with cognitive decline by Trails B.

CONCLUSION

We found little evidence of independent associations between lower 25-hydroxyvitamin D level and baseline global and executive cognitive function or incident cognitive decline.

25-Hydroxyvitamin D, dementia, and cerebrovascular pathology in elders receiving home services

BACKGROUND

Vitamin D deficiency has potential adverse effects on neurocognitive health and subcortical function. However, no studies have examined the association between vitamin D status, dementia, and cranial MRI indicators of cerebrovascular disease (CVD).

METHODS

Cross-sectional investigation of 25-hydroxyvitamin D [25(OH)D], dementia, and MRI measures of CVD in elders receiving home care (aged 65-99 years) from 2003 to 2007.

RESULTS

Among 318 participants, the mean age was 73.5 +/- 8.1 years, 231 (72.6%) were women, and 109 (34.3%) were black. 25(OH)D concentrations were deficient (<10 ng/mL) in 14.5% and insufficient (10-20 ng/mL) in 44.3% of participants. There were 76 participants (23.9%) with dementia, 41 of which were classified as probable AD. Mean 25(OH)D concentrations were lower in subjects with dementia (16.8 vs 20.0 ng/mL, p < 0.01). There was a higher prevalence of dementia among participants with 25(OH)D insufficiency (< or =20 ng/mL) (30.5% vs 14.5%, p < 0.01). 25(OH)D deficiency was associated with increased white matter hyperintensity volume (4.9 vs 2.9 mL, p < 0.01), grade (3.0 vs 2.2, p = 0.04), and prevalence of large vessel infarcts (10.1% vs 6.9%, p < 0.01). After adjustment for age, race, sex, body mass index, and education, 25(OH)D insufficiency (< or =20 ng/mL) was associated with more than twice the odds of all-cause dementia (odds ratio [OR] = 2.3, 95% confidence interval [CI] 1.2-4.2), Alzheimer disease (OR = 2.5, 95% CI 1.1-6.1), and stroke (with and without dementia symptoms) (OR = 2.0, 95% CI 1.0-4.0).

CONCLUSIONS

Vitamin D insufficiency and deficiency was associated with all-cause dementia, Alzheimer disease, stroke (with and without dementia symptoms), and MRI indicators of cerebrovascular disease. These findings suggest a potential vasculoprotective role of vitamin D.

Maternal vitamin D deficiency leads to cardiac hypertrophy in rat offspring

The aim of this study was to determine the effect of vitamin D deficiency from conception until 4 weeks of age on the development of the heart in rat offspring. Sprague-Dawley (SD) rats were fed either a vitamin D deplete or vitamin D-replete diet for 6 weeks prior to pregnancy, during pregnancy and throughout lactation. Cardiomyocyte number was determined in fixed hearts of offspring at postnatal day 3 and 4 weeks of age using an optical disector/fractionator stereological technique. In other litters, cardiomyocytes were isolated from freshly excised hearts to determine the proportion of mononucleated and binucleated cardiomyocytes. Maternal vitamin D deficiency had no effect on cardiomyocyte number, cardiomyocyte area, or the proportion of mononucleated/binucleated cardiomyocytes in 3-day-old male and female offspring. Importantly, however, vitamin D deficiency led to an increase in left ventricle (LV) volume that was accompanied by an increase in cardiomyocyte number and size, and in the proportion of mononucleated cardiomyocytes at 4 weeks of age. Our findings suggest that exposure to vitamin D deficiency in utero and early life leads to delayed maturation and subsequent enhanced growth (proliferation and hypertrophy) of cardiomyocytes in the LV. This may lead to altered cardiac function later in life.

Seasonal variation of maternal serum vitamin D in Newfoundland and Labrador

BACKGROUND

Research has suggested that vitamin D insufficiency and deficiency is common at northern latitudes, and that vitamin D insufficiency and deficiency may be common during pregnancy. We measured the serum 25-hydroxyvitamin D (25-[OH]D) status of pregnant women across the province of Newfoundland and Labrador in both summer and winter to investigate seasonal differences, age associations, and differences in geospatial distribution across the province.

METHODS

We uniformly and randomly sampled blood from pregnant women in each of 79 census consolidated subdivisions across Newfoundland and Labrador from January to March 2007 and from July to September 2007.

RESULTS

We obtained 304 samples from the end of winter (March) and 289 samples from the end of summer (September). Mean serum 25-(OH)D concentration was 52.1 nmol/L in winter and 68.6 nmol/L in summer (P < 0.001); 89% were vitamin D insufficient in the winter and 64% in the summer (P < 0.001); 6.6% were vitamin D deficient in winter and 1.7% in summer (P = 0.003), and younger women tended to be more vitamin D insufficient in the winter than older women. The geospatial distribution of vitamin D insufficiency tends to follow a north-south distribution in the winter.

CONCLUSIONS

A significant proportion of pregnant women in Newfoundland and Labrador are vitamin D insufficient. Vitamin D insufficiency may have important adverse health consequences for both the mother and the fetus. Further study is necessary to address health outcomes and effects of vitamin D supplementation and lifestyle changes in this population.

Vitamin D and cognitive performance in adults: a systematic review

Chronic low serum 25-hydroxyvitamin D (25OHD) concentrations are common in adults and are associated with numerous non-skeletal diseases. Vitamin D receptors (VDR) are located in the human cortex and hippocampus, which are key areas for cognition. The objective of this study was to systematically review all published data from the past 30 years which examined the association between serum 25OHD concentrations and cognitive performance in adults. An English and French Medline, PsycINFO and Cochrane Library search ranging from 1979 to 2008 indexed under the Medical Subject Heading (MeSH) terms 'Vitamin D' or 'Hydroxycholecalciferols' combined with the terms 'Dementia' or 'Cognition' or 'Cognition Disorders' or 'Delirium' or 'Memory' or 'Memory Disorders' or 'Orientation' or 'Executive Functions' or 'Attention' or 'Brain' or 'Neuropsychological Tests' was performed. Of the 99 selected studies, five observational studies met the selection criteria and were included in the final analysis. No prospective cohort study was found. The number of participants ranged from 32 to 9556 community-dwelling older adults (45-65% women). Three studies showed four significant positive associations between serum 25OHD concentrations and global cognitive functions, whereas three other studies exploring specific aspects of cognition showed 11 non-significant associations. This systematic review shows that the association between serum 25OHD concentrations and cognitive performance is not yet clearly established. The inconclusive results of the reviewed studies could be due to methodology, types of the cognitive tasks used and/or the cellular mechanisms of vitamin D.

ABNORMAL BEHAVIORAL ORGANIZATION OF GROOMING IN MICE LACKING THE VITAMIN D RECEPTOR GENE

Vitamin D is a steroid hormone with several important functions in the nervous system. Numerous human and animal data link alterations in the vitamin D system to various behavioral disorders. Grooming is an important element of rodent behavior with a general pattern of cephalocaudal progression (paw licking - nose/face wash - body wash - tail/genitals wash). Here we studied whether genetic ablation of vitamin D nuclear receptors (VDR) in mice may be associated with altered behavioral sequencing of grooming. Overall, VDR null mutant mice showed abnormal grooming, including a higher percentage of "incorrect" transitions and longer duration of "incorrect" grooming (contrary to the cephalocaudal progression); a higher percentage of interrupted grooming bouts; and the atypical regional distribution of grooming (more leg grooming, less body and tail/genitals grooming), compared to their wild-type controls. Grooming of heterozygous mice was similar to the wild-type group, indicating that abnormal grooming patterning is inherited as a recessive. In contrast, behavioral sequencing of another complex behavior (mating with a female) was unaltered in all three genotypes, suggesting grooming-specific abnormal sequencing in these mutant mice. Our results suggest that a neurosteroid vitamin D and VDR may play an important role in controlling sequencing of grooming in mice, and further confirm the important role of the vitamin D system and VDR in the regulation of behavior.

The association between birth weight, season of birth and latitude

BACKGROUND

Birth weight is known to fluctuate with month of birth and with latitude; however the mechanisms underlying these gradients remain unclear.

AIM

The study examined within-year fluctuations in birth weight across four regions in Australia.

SUBJECTS AND METHODS

We obtained the birth weight of singleton births of at least 37 weeks gestation from four regions: (a) southeast Queensland, (b) Sydney and surrounding districts, (c) Victoria, and (d) Tasmania. Seasonal fluctuations were examined after long-term trends had been removed. The amplitude, timing and variability of seasonal fluctuations were examined and compared across regions.

RESULTS

Each of the four regions had prominent annual periodicity with the peak birth weight occurring in spring. The amplitude of this signal ranged from 1.4 g (Victoria) to 7.7 g (southeast Queensland). There was no significant correlation between the amplitude of these fluctuations and the latitude of four regions. In addition, a second smaller autumn peak was identified.

CONCLUSION

Environmental factors that have regular within-year variation influence birth weight in Australia. The evidence suggests that at least two distinguishable seasonal processes contribute to the findings. Identifying the factors underlying these seasonal fluctuations could have implications from a public health perspective.

Epidemiologic evidence supporting the role of maternal vitamin D deficiency as a risk factor for the development of infantile autism

This study examines whether maternal vitamin D deficiency is a risk factor for infantile autism disease (IAD). We used epidemiologic data seasonal variation of birth rates and prevalence of IAD for cohorts born before 1985. For seven studies reporting spring-to-summer excess birth rates for IAD, the season progressed from broad near 30 degrees N latitude, spring/summer in midlatitudes, to winter at the highest latitude. Also, using data from 10 studies, we found a strong effective latitudinal (related to wintertime solar ultraviolet B radiation) increase in IAD prevalence. These findings are consistent with maternal vitamin D deficiency's being a risk factor for IAD, possibly by affecting fetal brain development as well as possibly by affecting maternal immune system status during pregnancy. Further investigation of this hypothesis is warranted.

Combination treatment with progesterone and vitamin D hormone may be more effective than monotherapy for nervous system injury and disease

More than two decades of pre-clinical research and two recent clinical trials have shown that progesterone (PROG) and its metabolites exert beneficial effects after traumatic brain injury (TBI) through a number of metabolic and physiological pathways that can reduce damage in many different tissues and organ systems. Emerging data on 1,25-dihydroxyvitamin D(3) (VDH), itself a steroid hormone, have begun to provide evidence that, like PROG, it too is neuroprotective, although some of its actions may involve different pathways. Both agents have high safety profiles, act on many different injury and pathological mechanisms, and are clinically relevant, easy to administer, and inexpensive. Furthermore, vitamin D deficiency is prevalent in a large segment of the population, especially the elderly and institutionalized, and can significantly affect recovery after CNS injury. The combination of PROG and VDH in pre-clinical and clinical studies is a novel and compelling approach to TBI treatment.

Developmental vitamin D deficiency alters dopamine turnover in neonatal rat forebrain

There is growing evidence that low vitamin D impacts adversely on brain development. The current study investigated the impact of developmental vitamin D (DVD) deficiency on dopamine and serotonin metabolism in the neonatal rat brain. DVD-deficiency resulted in an altered dopaminergic metabolic profile in the forebrain, with a decrease in the conversion of dihydroxyphenylacetic acid (DOPAC) to homovanillic acid (HVA). Correspondingly, expression of the enzyme required for this conversion, catechol-O-methyl transferase (COMT), was decreased. These results suggest that DVD-deficiency influences dopamine turnover during development.

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.