Neonatal Vitamin D and Associations with Longitudinal Changes of Eczema up to 25 Years of Age

BACKGROUND

Early-life vitamin D is a potentially modifiable risk factor for the development of eczema, but there is a lack of data on longitudinal associations.

METHOD

We measured 25(OH)D3 levels from neonatal dried blood spots in 223 high-allergy-risk children. Latent class analysis was used to define longitudinal eczema phenotype up to 25 years (4 subclasses). Skin prick tests (SPTs) to 6 allergens and eczema outcomes at 6 time points were used to define eczema/sensitization phenotypes. Associations between 25(OH)D3 and prevalent eczema and eczema phenotypes were assessed using logistic regression models.

RESULTS

Median 25(OH)D3 level was 32.5 nmol/L (P25-P75 = 23.1 nmol/L). Each 10 nmol/L increase in neonatal 25(OH)D3 was associated with a 26% reduced odds of early-onset persistent eczema (adjusted multinomial odds ratio (aMOR) = 0.74, 95% CI = 0.56-0.98) and 30% increased odds of early-onset-resolving eczema (aMOR = 1.30, 95% CI = 1.05-1.62) when compared to minimal/no eczema up to 12 years. Similar associations were seen for eczema phenotype up to 25 years. We did not see any strong evidence for the association between neonatal 25(OH)D3 and prevalent eczema or eczema/sensitization phenotype.

CONCLUSIONS

Higher neonatal 25(OH)D3 levels, a reflection of maternal vitamin D levels in pregnancy, may reduce the risk of early-onset persistent eczema.

Associations of the Gut Microbiome With Treatment Resistance in Schizophrenia

Importance

There is growing interest in the role of gut microbiome composition in schizophrenia. However, lifestyle factors are often neglected, and few studies have investigated microbiome composition in treatment-resistant schizophrenia.

Objective

To explore associations between the gut microbiome and schizophrenia diagnosis, treatment resistance, clozapine response, and treatment-related adverse effects while adjusting for demographic and lifestyle factors.

Design, Setting, and Participants

In this case-control study of adults aged 20 to 63 years, stool samples and data on demographic characteristics, lifestyle, and medication use were collected and gut microbiome measures obtained using shotgun metagenomics. Participants with a schizophrenia diagnosis were referred through psychiatric inpatient units and outpatient clinics. Data were collected for 4 distinct groups: control individuals without a psychiatric diagnosis (past or present), individuals with treatment-responsive schizophrenia taking nonclozapine antipsychotic medications, clozapine-responsive individuals with treatment-resistant schizophrenia, and clozapine-nonresponsive individuals with treatment-resistant schizophrenia. Participants were recruited between November 2020 and November 2021. Control individuals were recruited in parallel through posters and online advertisements and matched for age, sex, and body mass index (BMI) to the individuals with schizophrenia. Participants were excluded if taking antibiotics in the past 2 months, if unable to communicate in English or otherwise follow study instructions, were pregnant or planning to become pregnant, or had any concomitant disease or condition making them unsuited to the study per investigator assessment. Data were analyzed from January 2022 to March 2023.

Main Outcomes and Measures

Omics relationship matrices, α and β diversity, and relative abundance of microbiome features.

Results

Data were collected for 97 individuals (71 [74%] male; mean [SD] age, 40.4 [10.3] years; mean [SD] BMI, 32.8 [7.4], calculated as weight in kilograms divided by height in meters squared). Significant microbiome associations with schizophrenia were observed at multiple taxonomic and functional levels (eg, common species: b2, 30%; SE, 13%; adjusted P = .002) and treatment resistance (eg, common species: b2, 27%; SE, 16%; adjusted P = .03). In contrast, limited evidence was found for microbiome associations with clozapine response, constipation, or metabolic syndrome. Significantly decreased microbial richness was found in individuals with schizophrenia compared to control individuals (t95 = 4.25; P < .001; mean [SD] for control individuals, 151.8 [32.31]; mean [SD] for individuals with schizophrenia, 117.00 [36.2]; 95% CI, 18.6-51.0), which remained significant after a covariate and multiple comparison correction. However, limited evidence was found for differences in β diversity (weighted UniFrac) for schizophrenia diagnosis (permutational multivariate analysis of variance [PERMANOVA]: R2, 0.03; P = .02), treatment resistance (R2, 0.02; P = .18), or clozapine response (R2, 0.04; P = .08). Multiple differentially abundant bacterial species (19) and metabolic pathways (162) were found in individuals with schizophrenia, which were primarily associated with treatment resistance and clozapine exposure.

Conclusions and Relevance

The findings in this study are consistent with the idea that clozapine induces alterations to gut microbiome composition, although the possibility that preexisting microbiome differences contribute to treatment resistance cannot be ruled out. These findings suggest that prior reports of microbiome alterations in individuals with chronic schizophrenia may be due to medication or lifestyle factors and that future studies should incorporate these variables in their design and interpretation.

Mixture of air pollution, brominated flame retardants, polychlorinated biphenyls, per- and polyfluoroalkyl substances, and organochlorine pesticides in relation to vitamin D concentrations in pregnancy

Over two-thirds of pregnant women in the U.S. have insufficient 25(OH)D (Vitamin D) concentrations, which can adversely impact fetal health. Several pollutants have been associated with 25(OH)D, but have not been considered in the context of chemical co-exposures. We aimed to determine associations between a broad mixture of prenatal environmental chemical exposures and 25(OH)D concentrations in mid-pregnancy. Stored mid-pregnancy serum samples were assayed from 421 women delivering live births in Southern California in 2000-2003. 25(OH)D, six BFRs, eleven polychlorinated biphenyls (PCBs), six per- and polyfluoroalkyl substances, and two organochlorine pesticides were detected in ≥60% of specimens. Gestational exposures to airborne particulate matter ≤ 10 μm (PM10) and ≤ 2.5 μm (PM2.5), nitrogen monoxide (NO), nitrogen dioxide (NO2), and ozone concentrations were derived from monitoring station data. Bayesian Hierarchical Modeling (BHM) and Bayesian Kernel Machine Regression (BKMR) analyses estimated overall mixture and individual chemical associations accounting for co-exposures and covariates with mean 25(OH)D levels, and BHM was used to estimate associations with insufficient (<75 nMol/L) 25(OH)D levels. Non-mixture associations for each chemical were estimated with linear and logistic models. PM10 [BHM estimate: -0.133 nmol/l 95% Credible Interval (-0.240, -0.026)] was associated with lower 25(OH)D in BHM and BKMR. Higher quantiles of combined exposures were associated with lower 25(OH)D, though with wide credible intervals. In non-mixture models, PM10, PM2.5, NO, and NO2 were associated with lower concentrations, while O3 and PBDE153 were associated with higher 25(OH)D and/or lower insufficiency. While some chemicals were associated with increased and others with decreased 25(OH)D concentrations, the overall mixture was associated with lower concentrations. Mixture analyses differed from non-mixture regressions, highlighting the importance of mixtures approaches for estimating real-world associations.

Increasing dopamine synthesis in nigrostriatal circuits increases phasic dopamine release and alters dorsal striatal connectivity: implications for schizophrenia

One of the most robust neurochemical abnormalities reported in patients with schizophrenia is an increase in dopamine (DA) synthesis and release, restricted to the dorsal striatum (DS). This hyper functionality is strongly associated with psychotic symptoms and progresses in those who later transition to schizophrenia. To understand the implications of this progressive neurobiology on brain function, we have developed a model in rats which we refer to as EDiPs (Enhanced Dopamine in Prodromal schizophrenia). The EDiPs model features a virally mediated increase in dorsal striatal (DS) DA synthesis capacity across puberty and into adulthood. This protocol leads to progressive changes in behaviour and neurochemistry. Our aim in this study was to explore if increased DA synthesis capacity alters the physiology of DA release and DS connectivity. Using fast scan cyclic voltammetry to assess DA release we show that evoked/phasic DA release is increased in the DS of EDiPs rats, whereas tonic/background levels of DA remain unaffected. Using quantitative immunohistochemistry methods to quantify DS synaptic architecture we show a presynaptic marker for DA release sites (Bassoon) was elevated within TH axons specifically within the DS, consistent with the increased phasic DA release in this region. Alongside changes in DA systems, we also show increased density of vesicular glutamate transporter 1 (VGluT1) synapses in the EDiPs DS suggesting changes in cortical connectivity. Our data may prove relevant in understanding the long-term implications for DS function in response to the robust and prolonged increases in DA synthesis uptake and release reported in schizophrenia.

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

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

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

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

Animal Models of Relevance to the Schizophrenia Prodrome

Patients with schizophrenia often undergo a prodromal phase prior to diagnosis. Given the absence of significant therapeutic improvements, attention has recently shifted to the possibility of intervention during this early stage to delay or diminish symptom severity or even prevent onset. Unfortunately, the 20 or so trials of intervention to date have not been successful in either preventing onset or improving long-term outcomes in subjects who are at risk of developing schizophrenia. One reason may be that the biological pathways an effective intervention must target are not static. The prodromal phase typically occurs during late adolescence, a period during which a number of brain circuits and structures are still maturing. We propose that developing a deeper understanding of which circuits/processes and brain structures are still maturing at this time and which processes drive the transition to schizophrenia will take us a step closer to developing better prophylactic interventions. Fortunately, such knowledge is now emerging from clinical studies, complemented by work in animal models. Our task here is to describe what would constitute an appropriate animal model to study and to potentially intervene in such processes. Such a model would allow invasive analysis of the cellular and molecular substrates of the progressive neurobiology that defines the schizophrenia prodrome and hopefully offer valuable insights into potential prophylactic targets.

Does the gut microbiome mediate antipsychotic-induced metabolic side effects in schizophrenia?

INTRODUCTION

Second-generation antipsychotics (SGAs) are the most effective treatment for people with schizophrenia. Despite their effectiveness in treating psychotic symptoms, they have been linked to metabolic, cardiovascular and gastrointestinal side-effects. The gut microbiome has been implicated in potentiating symptoms of schizophrenia, response to treatment and medication-induced side effects and thus presents a novel target mediating second-generation antipsychotic-induced side effects in patients.

AREAS COVERED

This narrative review presents evidence from clinical and pre-clinical studies exploring the relationship between the gut microbiome, schizophrenia, second-generation antipsychotics and antipsychotic-induced side-effects. It also covers evidence for psychobiotic treatment as a potential supplementary therapy for people with schizophrenia.

EXPERT OPINION

The gut microbiome has the potential to mediate antipsychotic-induced side-effects in people with schizophrenia. Microbiome-focused treatments should be considered in combination with standard therapy in order to ameliorate debilitating drug-induced side effects, increase quality of life and potentially improve psychotic symptoms. Future studies should aim to collect not only microbiome data, but also metabolomic measures, dietary information and behavioral data.

Developmental Vitamin D Deficiency in Pregnant Rats Does Not Induce Preeclampsia

Preeclampsia is a pregnancy disorder characterized by hypertension. Epidemiological studies have associated preeclampsia with an increased risk of neurodevelopmental disorders in offspring, such as autism and schizophrenia. Preeclampsia has also been linked with maternal vitamin D deficiency, another candidate risk factor also associated with autism. Our laboratory has established a gestational vitamin-D-deficient rat model that shows consistent and robust behavioural phenotypes associated with autism- and schizophrenia-related animal models. Therefore, we explored here whether this model also produces preeclampsia as a possible mediator of behavioural phenotypes in offspring. We showed that gestational vitamin D deficiency was not associated with maternal blood pressure or proteinuria during late gestation. Maternal and placental angiogenic and vasculogenic factors were also not affected by a vitamin-D-deficient diet. We further showed that exposure to low vitamin D levels did not expose the placenta to oxidative stress. Overall, gestational vitamin D deficiency in our rat model was not associated with preeclampsia-related features, suggesting that well-described behavioural phenotypes in offspring born to vitamin-D-deficient rat dams are unlikely to be mediated via a preeclampsia-related mechanism.

Vitamin D deficiency worsens maternal diabetes induced neurodevelopmental disorder by potentiating hyperglycemia-mediated epigenetic changes

Many studies have shown that vitamin D (VD) deficiency may be a risk factor for neurodevelopmental disorders, such as autism spectrum disorders (ASDs) and schizophrenia, although causative mechanisms remain unknown. In this study, we investigated the potential role and effect of VD on maternal diabetes induced autism-related phenotypes. The in vitro study found that enhancing genomic VD signaling by overexpressing the VD receptor (VDR) in human neural progenitor cells ACS-5003 protects against hyperglycemia-induced oxidative stress and inflammation by activating Nrf2 and its target genes, including SOD2 and HMOX1, and accordingly, VDR gene knockdown worsens the problem. In the two in vivo models we explored, maternal diabetes was used to establish an animal model of relevance to ASD, and mice lacking 25-hydroxyvitamin D 1-alpha-hydroxylase (the rate-limiting enzyme in the synthesis of 1,25(OH)2D3) were used to develop a model of VD deficiency (VDD). We show that although prenatal VDD itself does not produce ASD-relevant phenotypes, it significantly potentiates maternal diabetes induced epigenetic modifications and autism-related phenotypes. Postnatal manipulation of VD has no effect on maternal diabetes induced autism-related phenotypes. We conclude that VDD potentiates maternal diabetes induced autism-related phenotypes in offspring by epigenetic mechanisms. This study adds to other preclinical studies linking prenatal VDD with a neurodevelopmental disorder.

Maternal Vitamin D Levels During Pregnancy in Association With Autism Spectrum Disorders (ASD) or Intellectual Disability (ID) in Offspring; Exploring Non-linear Patterns and Demographic Sub-groups

Increasing vitamin D deficiency and evidence for vitamin D's role in brain and immune function have recently led to studies of neurodevelopment; however, few are specific to autism spectrum disorder (ASD) and vitamin D in pregnancy, a likely susceptibility period. We examined this in a case-control study of 2000-2003 Southern Californian births; ASD and intellectual disability (ID) were identified through the Department of Developmental Services and controls from birth certificates (N = 534, 181, and 421, respectively, in this analysis). Total 25-Hydroxyvitamin D (25(OH)D) was measured in mid-pregnancy serum, categorized as deficient (<50 nmol/L), insufficient (50-74 nmol/L), or sufficient (≥75 nmol/L, referent category), and examined continuously (per 25 nmol/L). Crude and adjusted odds ratios (AORs) and 95% confidence intervals (95% CI) were calculated. Non-linearity was examined with cubic splines. AORs (95% CI) for ASD were 0.79 (0.49-1.3) for maternal deficiency (9.5%), 0.93 (0.68-1.3) for insufficiency (25.6%), and 0.95 (0.86, 1.05) for linear continuous 25(OH)D. Results were similarly null for ASD with or without ID, and ID only. Interactions were observed; non-Hispanic whites (NHW) (AOR = 0.82, 95% CI = 0.69-0.98) and males (AOR = 0.89, 95% CI = 0.80-0.99) had protective associations for ASD with continuous 25(OH)D. A positive association with ASD was observed in females (AOR = 1.40, 95% CI = 1.06-1.85). With splines, a non-linear inverted j-shaped pattern was seen overall (P = 0.009 for non-linearity), with the peak around 100 nmol/L; a non-linear pattern was not observed among NHW, females, nor for ID. Our findings from a large study of ASD and prenatal vitamin D levels indicate that further research is needed to investigate non-linear patterns and potentially vulnerable sub-groups. LAY SUMMARY: We studied whether mothers' vitamin D levels during pregnancy were related to their children having autism (or low IQ) later. Low vitamin D levels were not related to greater risk of autism or low IQ in children overall. With higher levels of mothers' vitamin D, risk of autism went down in boys, but went up in girls. Risk of autism also went down in children of non-Hispanic white mothers with higher vitamin D levels, but we did not find a relation in other race/ethnic groups.

Genome-wide association study identifies 143 loci associated with 25 hydroxyvitamin D concentration

Vitamin D deficiency is a candidate risk factor for a range of adverse health outcomes. In a genome-wide association study of 25 hydroxyvitamin D (25OHD) concentration in 417,580 Europeans we identify 143 independent loci in 112 1-Mb regions, providing insights into the physiology of vitamin D and implicating genes involved in lipid and lipoprotein metabolism, dermal tissue properties, and the sulphonation and glucuronidation of 25OHD. Mendelian randomization models find no robust evidence that 25OHD concentration has causal effects on candidate phenotypes (e.g. BMI, psychiatric disorders), but many phenotypes have (direct or indirect) causal effects on 25OHD concentration, clarifying the epidemiological relationship between 25OHD status and the health outcomes examined in this study.

Genetic Contributions to Maternal and Neonatal Vitamin D Levels

Vitamin D is essential for several physiological functions and biological processes. Increasing levels of maternal vitamin D are required throughout pregnancy as a unique source of vitamin D for the fetus, and consequently maternal vitamin D deficiency may result in several adverse outcomes in newborns. However, the genetic regulation of vitamin D in pregnancy and at birth is not yet well understood. We performed genome-wide association studies of maternal midgestational serum-derived and neonatal blood-spot-derived total 25-hydroxyvitamin D from a case-control study of autism spectrum disorder (ASD). We identified one fetal locus (rs4588) significantly associated with neonatal vitamin D levels in the GC gene, encoding the binding protein for the transport and function of vitamin D. We also found suggestive cross-associated loci for neonatal and maternal vitamin D near immune genes, such as CXCL6-IL8 and ACKR1 We found no interactions with ASD. However, when including a set of cases with intellectual disability but not ASD (N = 179), we observed a suggestive interaction between decreased levels of neonatal vitamin D and a specific maternal genotype near the PKN2 gene. Our results suggest that genetic variation influences total vitamin D levels during pregnancy and at birth via proteins in the vitamin D pathway, but also potentially via distinct mechanisms involving loci with known roles in immune function that might be involved in vitamin D pathophysiology in pregnancy.

Enhanced Dopamine in Prodromal Schizophrenia (EDiPS): a new animal model of relevance to schizophrenia

One of the most robust neurochemical abnormalities reported in patients living with schizophrenia is an increase in dopamine (DA) synthesis and release in the dorsal striatum (DS). Importantly, it appears that this increase progresses as a patient transitions from a prodromal stage to the clinical diagnosis of schizophrenia. Here we have recreated this pathophysiology in an animal model by increasing the capacity for DA synthesis preferentially within the DS. To achieve this we administer a genetic construct containing the rate-limiting enzymes in DA synthesis—tyrosine hydroxylase (TH), and GTP cyclohydrolase 1 (GCH1) (packaged within an adeno-associated virus)—into the substantia nigra pars compacta (SNpc) of adolescent animals. We refer to this model as “Enhanced Dopamine in Prodromal Schizophrenia” (EDiPS). We first confirmed that the TH enzyme is preferentially increased in the DS. As adults, EDiPS animals release significantly more DA in the DS following a low dose of amphetamine (AMPH), have increased AMPH-induced hyperlocomotion and show deficits in pre-pulse inhibition (PPI). The glutamatergic response to AMPH is also altered, again in the DS. EDiPS represents an ideal experimental platform to (a) understand how a preferential increase in DA synthesis capacity in the DS relates to “positive” symptoms in schizophrenia; (b) understand how manipulation of DS DA may influence other neurotransmitter systems shown to be altered in patients with schizophrenia; (c) allow researchers to follow an “at risk”-like disease course from adolescence to adulthood; and (d) ultimately allow trials of putative prophylactic agents to prevent disease onset in vulnerable populations.

Newborn vitamin D levels in relation to autism spectrum disorders and intellectual disability: A case-control study in california

Vitamin D deficiency has been increasing concurrently with prevalence of autism spectrum disorders (ASD), and emerging evidence suggests vitamin D is involved in brain development. Most prior studies of ASD examined vitamin D levels in children already diagnosed, but a few examined levels during perinatal development, the more likely susceptibility period. Therefore, we examined newborn vitamin D levels in a case-control study conducted among births in 2000-2003 in southern California. Children with ASD (N = 563) or intellectual disability (ID) (N = 190) were identified from the Department of Developmental Services and compared to population controls (N = 436) identified from birth certificates. 25-hydroxyvitamin D (25(OH)D) was measured in archived newborn dried blood spots by a sensitive assay and corrected to sera equivalents. We categorized 25(OH) D levels as deficient (<50 nmol/L), insufficient (50-74 nmol/L), and sufficient (≥75 nmol/L), and also examined continuous levels, using logistic regression. The adjusted odds ratios (AOR) and 95% confidence intervals for ASD were 0.96 (0.64-1.4) for 25(OH)D deficiency (14% of newborns) and 1.2 (0.86-1.6) for insufficiency (26% of newborns). The AORs for continuous 25(OH)D (per 25 nmol/L) were 1.0 (0.91-1.09) for ASD and 1.14 (1.0-1.30) for ID. Thus, in this relatively large study of measured newborn vitamin D levels, our results do not support the hypothesis of lower 25(OH)D being associated with higher risk of ASD (or ID), although we observed suggestion of interactions with sex and race/ethnicity. 25(OH)D levels were relatively high (median 84 nmol/L in controls), so results may differ in populations with higher prevalence of low vitamin D levels. Autism Res 2019, 12: 989-998. © 2019 International Society for Autism Research, Wiley Periodicals, Inc. LAY SUMMARY: We studied whether vitamin D levels measured at birth were related to whether a child later developed autism (or low IQ). Our results did not show that children with autism, or low IQ, overall had lower vitamin D levels at birth than children without autism. Vitamin D levels were fairly high, on average, in these children born in Southern California.

The placental immune response is dysregulated developmentally vitamin D deficient rats: Relevance to autism

Emerging evidence suggests that maternal or developmental vitamin D (DVD) deficiency is a risk factor for Autism Spectrum Disorders. A well-established association has also been found between gestational infection and increased incidence of autism. Placenta mediates the maternal immune response in respect to the foetus. The placenta is also a major source of vitamin D and locally produced vitamin D is an essential regulator of immune function during pregnancy. Here we investigate the effects of DVD-deficiency on baseline placental immune status and in response to the well-known viral and bacterial immune activating agents polyriboinosinic-polyribocytidylic acid (poly(I:C) and lipopolysaccharide (LPS). We show DVD-deficiency does not affect baseline inflammatory cytokines in placenta. However, when challenged with poly(I:C) but not LPS, DVD-deficient placentas from male foetuses had higher production of IL-6 and 1L-1β compared to control placentas. This suggests the developing DVD-deficient male foetus may be particularly vulnerable to maternal viral exposures. This in turn may have adverse implications for the developing male brain. In conclusion, a dysregulated placental immune response may provide a plausible mechanism for both the epidemiological links between DVD-deficiency and increased male incidence of developmental conditions such as autism.

Differential expression of vitamin D-associated enzymes and receptors in brain cell subtypes

Accumulating evidence indicates that the active form of vitamin D, 1,25(OH)2D3, can be considered as a neurosteroid. However, the cerebral expression of vitamin D-associated enzymes and receptors remains controversial. With the idea of carrying out a comparative study in mind, we compared the transcript expression of Cyp27a1, Cyp27b1, Cyp24a1, Vdr and Pdia3 in purified cultures of astrocytes, endothelial cells, microglia, neurons and oligodendrocytes. We observed that endothelial cells and neurons can possibly transform the inactive cholecalciferol into 25(OH)D3. It can then be metabolised into 1,25(OH)2D3, by neurons or microglia, before being transferred to astrocytes where it can bind to VDR and initiate gene transcription or be inactivated when in excess. Alternatively, 1,25(OH)2D3 can induce autocrine or paracrine rapid non-genomic actions via PDIA3 whose transcript is abundantly expressed in all cerebral cell types. Noticeably, brain endothelial cells appear as a singular subtype as they are potentially able to transform cholecalciferol into 25(OH)D3 and exhibit a variable expression of Pdia3, according to 1,25(OH)2D3 level. Altogether, our data indicate that, within the brain, vitamin D may trigger major auto-/paracrine non genomic actions, in addition to its well documented activities as a steroid hormone.

Early life vitamin D depletion alters the postnatal response to skeletal loading in growing and mature bone

There is increasing evidence of persistent effects of early life vitamin D exposure on later skeletal health; linking low levels in early life to smaller bone size in childhood as well as increased fracture risk later in adulthood, independently of later vitamin D status. A major determinant of bone mass acquisition across all ages is mechanical loading. We tested the hypothesis in an animal model system that early life vitamin D depletion results in abrogation of the response to mechanical loading, with consequent reduction in bone size, mass and strength during both childhood and adulthood. A murine model was created in which pregnant dams were either vitamin D deficient or replete, and their offspring moved to a vitamin D replete diet at weaning. Tibias of the offspring were mechanically loaded and bone structure, extrinsic strength and growth measured both during growth and after skeletal maturity. Offspring of vitamin D deplete mice demonstrated lower bone mass in the non loaded limb and reduced bone mass accrual in response to loading in both the growing skeleton and after skeletal maturity. Early life vitamin D depletion led to reduced bone strength and altered bone biomechanical properties. These findings suggest early life vitamin D status may, in part, determine the propensity to osteoporosis and fracture that blights later life in many individuals.

Developmental vitamin D deficiency and autism: Putative pathogenic mechanisms

Autism is a neurodevelopmental disease that presents in early life. Despite a considerable amount of studies, the neurobiological mechanisms underlying autism remain obscure. Both genetic and environmental factors are involved in the development of autism. Vitamin D deficiency is emerging as a consistently reported risk factor in children. One reason for the prominence now being given to this risk factor is that it would appear to interact with several other epidemiological risk factors for autism. Vitamin D is an active neurosteroid and plays crucial neuroprotective roles in the developing brain. It has important roles in cell proliferation and differentiation, immunomodulation, regulation of neurotransmission and steroidogenesis. Animal studies have suggested that transient prenatal vitamin D deficiency is associated with altered brain development. Here we review the potential neurobiological mechanisms linking prenatal vitamin D deficiency and autism and also discuss what future research targets must now be addressed.

Vitamin D and the brain: Genomic and non-genomic actions

1,25(OH)₂D₃ (vitamin D) is well-recognized as a neurosteroid that modulates multiple brain functions. A growing body of evidence indicates that vitamin D plays a pivotal role in brain development, neurotransmission, neuroprotection and immunomodulation. However, the precise molecular mechanisms by which vitamin D exerts these functions in the brain are still unclear. Vitamin D signalling occurs via the vitamin D receptor (VDR), a zinc-finger protein in the nuclear receptor superfamily. Like other nuclear steroids, vitamin D has both genomic and non-genomic actions. The transcriptional activity of vitamin D occurs via the nuclear VDR. Its faster, non-genomic actions can occur when the VDR is distributed outside the nucleus. The VDR is present in the developing and adult brain where it mediates the effects of vitamin D on brain development and function. The purpose of this review is to summarise the in vitro and in vivo work that has been conducted to characterise the genomic and non-genomic actions of vitamin D in the brain. Additionally we link these processes to functional neurochemical and behavioural outcomes. Elucidation of the precise molecular mechanisms underpinning vitamin D signalling in the brain may prove useful in understanding the role this steroid plays in brain ontogeny and function.

Vitamin D treatment during pregnancy prevents autism-related phenotypes in a mouse model of maternal immune activation

Background

Prenatal exposure to infection is a recognized environmental risk factor for neuropsychiatric disorders of developmental origins such as autism or schizophrenia. Experimental work in animals indicates that this link is mediated by maternal immune activation (MIA) involving interactions between cytokine-associated inflammatory events, oxidative stress, and other pathophysiological processes such as hypoferremia and zinc deficiency. Maternal administration of the viral mimic polyriboinosinic-polyribocytidylic acid (poly(I:C)) in mice produces several behavioral phenotypes in adult offspring of relevance to autism spectrum disorder (ASD) and other neurodevelopmental disorders.

Methods

Here, we investigated whether some of these phenotypes might also present in juveniles. In addition, given the known immunomodulatory and neuroprotective effects of vitamin D, we also investigated whether the co-administration of vitamin D could block MIA-induced ASD-related behaviors. We co-administered the hormonally active form of vitamin D, 1α,25 dihydroxy vitamin D3 (1,25OHD), simultaneously with poly(I:C) and examined (i) social interaction, stereotyped behavior, emotional learning and memory, and innate anxiety-like behavior in juveniles and (ii) the levels of the pro-inflammatory cytokines IL-1β, IL-6 and TNF-α in maternal plasma and fetal brains.

Results

We show that like adult offspring that were exposed to MIA, juveniles display similar deficits in social approach behavior. Juvenile MIA offspring also show abnormal stereotyped digging and impaired acquisition and expression of tone-cued fear conditioning. Importantly, our study reveals that prenatal administration of 1,25OHD abolishes all these behavioral deficits in poly(I:C)-treated juveniles. However, prenatal administration of vitamin D had no effect on pro-inflammatory cytokine levels in dams or in fetal brains suggesting the anti-inflammatory actions of vitamin D are not the critical mechanism for its preventive actions in this ASD animal model.

Conclusions

This work raises the possibility that early dietary supplementation with vitamin D may open new avenues for a successful attenuation or even prevention of neurodevelopmental disorders following maternal inflammation during pregnancy.

Electronic supplementary material

The online version of this article (doi:10.1186/s13229-017-0125-0) contains supplementary material, which is available to authorized users.

Predictors of vitamin D status in New Zealand preschool children

Vitamin D deficiency has adverse health effects in young children. Our aims were to determine predictors of vitamin D status and then to use these factors to develop a practical tool to predict low 25(OH)D concentrations in preschool New Zealand children. A cross-sectional sample of 1329 children aged 2 to <5 years were enrolled from throughout New Zealand in late-winter to spring 2012. 25-Hydroxyvitamin D (25(OH)D) was measured on dried blood spot (DBS) samples collected using finger-prick sampling. Caregivers completed a questionnaire. Mean (SD) DBS 25(OH)D concentration was 52(19)nmol/L. 25(OH)D < 25 nmol/L was present in 86(7%), 25(OH)D < 50 nmol/L in 642(48%), 25(OH)D 50- < 75 nmol/L in 541(41%) and 25(OH)D > 75 nmol/L in 146(11%) of children. Factors independently associated with the risk of 25(OH)D < 25 nmol/L were female gender (OR 1.92,95%CI 1.17-3.14), other non-European ethnicities (not including Māori or Pacific) (3.51,1.89-6.50), had olive-dark skin colour (4.52,2.22-9.16), did not take vitamin D supplements (2.56,1.06-6.18), had mothers with less than secondary-school qualifications (5.00,2.44-10.21) and lived in more deprived households (1.27,1.06-1.53). Children who drank toddler milk (vitamin D fortified cow's milk formula marketed to young children) had a zero risk of 25(OH)D < 25 nmol/L. The predictive tool identified children at risk of 25(OH)D < 25 nmol/L with sensitivity 42%, specificity 97% and ROC area-under-curve 0.76(95%CI 0.67-0.86, p < 0.001). Predictors of low vitamin D status were consistent with those identified in previous studies of New Zealand children. The tool had insufficient predictive ability for use in clinical situations, and suggests a need to promote safe, inexpensive testing to determine vitamin D status in preschool children.

The Relationship between Vitamin D Status and Allergic Diseases in New Zealand Preschool Children

Recent research on vitamin D in young children has expanded from bone development to exploring immunomodulatory effects. Our aim was to investigate the relationship of vitamin D status and allergic diseases in preschool-aged children in New Zealand. Dried capillary blood spots were collected from 1329 children during late-winter to early-spring for 25(OH)D measurement by LC-MS/MS. Caregivers completed a questionnaire about their child's recent medical history. Analysis was by multivariable logistic regression. Mean 25(OH)D concentration was 52(SD19) nmol/L, with 7% of children <25 nmol/L and 49% <50 nmol/L. Children with 25(OH)D concentrations ≥75 nmol/L (n = 29) had a two-fold increased risk for parent-report of doctor-diagnosed food allergy compared to children with 25(OH)D 50-74.9 nmol/L (OR = 2.21, 1.33-3.68, p = 0.002). No associations were present between 25(OH)D concentration and presence of parent-reported eczema, allergic rhinoconjunctivitis or atopic asthma. Vitamin D deficiency was not associated with several allergic diseases in these New Zealand preschool children. In contrast, high 25(OH)D concentrations were associated with a two-fold increased risk of parental-report food allergy. This increase supports further research into the association between vitamin D status and allergic disease in preschool children.

Infancy and pediatric cancer: an exploratory study of parent psychological distress

BACKGROUND

Research on the psychological experiences of parents of infants within pediatric oncology is sparse. This study examined rates and indicative risk factors for psychological distress in parents where there is either an infant patient or infant sibling of a patient.

METHODS

Participants were mothers (n = 41) and fathers (n = 25) of infants under 2 years who either had a cancer diagnosis (n = 37; infant patients) or was an infant sibling of an older child with cancer (n = 29; infant siblings) recruited from a single oncology center. There were 21 couple dyads. Parents completed the Depression Anxiety Stress Scales short form and the Posttraumatic Stress Disorder Checklist.

RESULTS

Mothers (47.5%) and fathers (37.5%) reported elevated, cancer-related posttraumatic stress symptoms. Rates of depression (12.2% of mothers and 12.0% of fathers) and anxiety symptoms (17.1% of mothers and 8.0% of fathers) were lower. Compared with parents of infant patients, parents of infant siblings reported significantly higher rates of depressive symptoms and trends toward higher rates of posttraumatic stress symptoms and anxiety symptoms. Parent anxiety was higher with increased time post diagnosis. No demographic or illness-related variables were associated with psychological distress, with the exception of the number of children in the family.

CONCLUSIONS

Parent-child relationships are of fundamental importance during infancy. This study provides novel data highlighting the psychological impact for parents when a cancer diagnosis is made during this critical developmental period, including the contribution of family structure to parental distress. Results provide further support for applying a traumatic stress framework when exploring parent experiences of pediatric cancer. Copyright © 2016 John Wiley & Sons, Ltd.

Rhinoviruses significantly affect day-to-day respiratory symptoms of children with asthma

BACKGROUND

Viruses are frequently associated with acute exacerbations of asthma, but the extent to which they contribute to the level of day-to-day symptom control is less clear.

OBJECTIVE

We sought to explore the relationship between viral infections, host and environmental factors, and respiratory symptoms in children.

METHODS

Sixty-seven asthmatic children collected samples twice weekly for an average of 10 weeks. These included nasal wash fluid and exhaled breath for PCR-based detection of viral RNA, lung function measurements, and records of medication use and asthma and respiratory symptoms in the previous 3 days. Atopy, mite allergen exposure, and vitamin D levels were also measured. Mixed-model regression analyses were performed.

RESULTS

Human rhinoviruses (hRVs) were detected in 25.5% of 1232 nasal samples and 11.5% of breath samples. Non-hRV viruses were detected in less than 3% of samples. hRV in nasal samples was associated with asthma symptoms (cough and phlegm: odds ratio = 2.0; 95% CI = 1.4-2.86, P = .0001; wheeze and chest tightness: odds ratio = 2.34, 95% CI = 1.55-3.52, P < .0001) and with cold symptoms, as reported concurrently with sampling and 3 to 4 days later. No differences were found between the 3 hRV genotypes (hRV-A, hRV-B, and hRV-C) in symptom risk. A history of inhaled corticosteroid use, but not atopic status, mite allergen exposure, or vitamin D levels, modified the association between viruses and asthma symptoms.

CONCLUSION

The detection of nasal hRV was associated with a significantly increased risk of day-to-day asthma symptoms in children. Host, virus genotype, and environmental factors each had only a small or no effect on the relationship of viral infections to asthma symptoms.

Autism spectrum disorder and low vitamin D at birth: a sibling control study

BACKGROUND

Insufficient vitamin D activity has attracted increasing interest as a possible underlying risk factor in disorders of the central nervous system, including autism.

METHODS

In this study, 25-hydroxyvitamin D (25(OH)D) was analysed in 58 Sweden-born sibling pairs, in which one child had autism spectrum disorder (ASD) and the other did not. The study group consisted of two representative samples; 47 Gothenburg sibling pairs with mixed ethnicities and 11 Stockholm sibling pairs with Somali background. 25(OH)D levels were analysed in the stored dried blood spots taken in the neonatal period for metabolic screening.

RESULTS

The collapsed group of children with ASD had significantly lower vitamin D levels (M = 24.0 nM, SD = 19.6) as compared with their siblings (M = 31.9 nM, SD = 27.7), according to a paired samples t-test (P = 0.013). The difference was - most likely - not only accounted for by a difference in season of birth between ASD and non-ASD siblings since the mean 25(OH)D levels differed with similar effect size between the sibling pairs born during winter and summer, respectively. All children with African/Middle East background, both the children with ASD and their non-ASD siblings, had vitamin D deficiency.

CONCLUSIONS

The findings suggest that low prenatal vitamin D may act as a risk factor for ASD, however, there is a need for replication with larger samples. Future research should study whether or not adequate supplementation of vitamin D to pregnant women might lower the risk for ASD in the offspring.

Season of birth, neonatal vitamin D status, and cardiovascular disease risk at 35 y of age: a cohort study from Sweden

BACKGROUND

Lower vitamin D status during gestation may be associated with cardiovascular disease risk later in life. No studies have assessed this hypothesis with a follow-up time reaching beyond childhood.

OBJECTIVE

The objective was to assess the link between season of birth, neonatal 25-hydroxyvitamin D₃ [25(OH)D₃] status, and adult cardiovascular disease risk.

DESIGN

Markers of cardiovascular and metabolic disease risk were measured in 284 subjects aged 35 y, born either at the end of the winter or at the end of the summer of 1975. In 275 of these 284 subjects, concentrations of neonatal 25(OH)D₃ were measured in dried blood samples by using a highly sensitive liquid chromatography-tandem mass spectroscopy method.

RESULTS

Subjects born after the winter had lower neonatal 25(OH)D₃ concentrations than did those born after the summer (31.5 compared with 48.5 nmol/L; P < 0.001). In regression analyses adjusted for sex, season of birth, postnatal age at neonatal sample collection, preterm birth, maternal age, education, smoking, fish consumption per week, exercise per week, and current 25-hydroxyvitamin D, higher neonatal 25(OH)D₃ (per 50 nmol/L) was associated with 25.8% (95% CI: 1.0%, 58.4%) higher fasting insulin in adult life, 29.6% (5.1%, 58.4%) higher triglycerides, and 4.64 (95% CI: 1.93, 7.36) mmol/L higher serum cholesterol in women. Neonatal 25(OH)D₃ (per 1 nmol/L) was directly associated with risk of adult overweight (OR: 1.03; 95% CI: 1.01, 1.05) and with adult obesity in women (OR: 1.09; 95% CI: 1.02, 1.17). Neonatal 25(OH)D₃ was not associated with adult aortic pulse wave velocity, blood pressure, fasting glucose, HDL, LDL, or C-reactive protein. Season of birth was not associated with any of the adult outcomes.

CONCLUSIONS

Higher neonatal 25(OH)D₃ was associated with higher fasting insulin, triglyceride, and cholesterol (in women) concentrations and with a higher risk of overweight at 35 y of age but not with other adult cardiovascular disease risk factors.

Abstract A54: Vitamin D and risk of colorectal cancer: The Melbourne Collaborative Cohort Study

Introduction: Several nested case-control studies have found that high serum or plasma levels of 25-hydroxy vitamin D (25OHD) are associated with decreased risk of colorectal cancer. Most of these studies were conducted in areas with lower UVB irradiance than Australia. To determine whether 25OHD was associated with reduced risk of colorectal cancer in Australia, we conducted a case-cohort study nested within a cohort study.

Methods: The Melbourne Collaborative Cohort recruited 41,514 participants from 1990-94. At baseline, blood samples were collected. This study was restricted to participants with dried blood spots from baseline blood samples. We included a random sample of 2996 people (i.e. subcohort), together with all incident cases of colorectal cancer during follow-up. 25OHD was measured using liquid chromatography tandem mass-spectrometry. The data were analysed with Cox regression, using Barlow's method to allow for the case-cohort design and adjusted for sex, education, physical activity, waist circumference, country of birth (southern Europe versus other), smoking, and intakes of alcohol, energy, margarine and processed meat.

Results: The method showed high reliability; the intra-class correlation from 500 repeat measurements was 0.78 (95% CI: 0.75, 0.82). In a separate calibration study, there was good agreement between 25OHD measurements from dried blood spots and plasma and for the subcohort, the predicted mean plasma concentrations were 55.5 nmol/L for males and 46.0 for females. During an average of 14 years of follow-up, we identified 563 cases. There was a weak, non-statistically significant inverse association between 25OHD and colorectal cancer; the hazard ratio for the highest versus lowest quartile was 0.82 (95% CI: 0.61, 1.10, p trend = 0.20).

Conclusions: In this Australian study, the association between 25OHD and risk of colorectal cancer was weaker than has been observed in studies from Europe and North America.

Citation Format: Dallas R. English, Elizabeth J. Williamson, Alicia K. Heath, Peter R. Ebeling, Laura Baglietto, Allison M. Hodge, Graham G. Giles, David Kvaskoff, Darryl Eyles. Vitamin D and risk of colorectal cancer: The Melbourne Collaborative Cohort Study. [abstract]. In: Proceedings of the Twelfth Annual AACR International Conference on Frontiers in Cancer Prevention Research; 2013 Oct 27-30; National Harbor, MD. Philadelphia (PA): AACR; Can Prev Res 2013;6(11 Suppl): Abstract nr A54.

Transient activation of dopaminergic neurons during development modulates visual responsiveness, locomotion and brain activity in a dopamine ontogeny model of schizophrenia

It has been observed that certain developmental environmental risk factors for schizophrenia when modeled in rodents alter the trajectory of dopaminergic development, leading to persistent behavioural changes in adults. This has recently been articulated as the "dopamine ontogeny hypothesis of schizophrenia". To test one aspect of this hypothesis, namely that transient dopaminergic effects during development modulate attention-like behavior and arousal in adults, we turned to a small-brain model, Drosophila melanogaster. By applying genetic tools allowing transient activation or silencing of dopaminergic neurons in the fly brain, we investigated whether a critical window exists during development when altered dopamine (DA) activity levels could lead to impairments in arousal states in adult animals. We found that increased activity in dopaminergic neurons in later stages of development significantly increased visual responsiveness and locomotion, especially in adult males. This misallocation of visual salience and hyperactivity mimicked the effect of acute methamphetamine feeding to adult flies, suggesting up-regulated DA signaling could result from developmental manipulations. Finally, brain recordings revealed significantly reduced gamma-band activity in adult animals exposed to the transient developmental insult. Together, these data support the idea that transient alterations in DA signaling during development can permanently alter behavior in adults, and that a reductionist model such as Drosophila can be used to investigate potential mechanisms underlying complex cognitive disorders such as schizophrenia.

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

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

Vitamin D in fetal brain development

In this review we will provide a concise summary of the evidence implicating a role for vitamin D in the developing brain. Vitamin D is known to affect a diverse array of cellular functions. Over the past 10 years data has emerged implicating numerous ways in which this vitamin could also affect the developing brain including its effects on cell differentiation, neurotrophic factor expression, cytokine regulation, neurotransmitter synthesis, intracellular calcium signaling, anti-oxidant activity, and the expression of genes/proteins involved in neuronal differentiation, structure and metabolism. Dysfunction in any of these processes could adversely affect development. Although there are many ways to study the effects of vitamin D on the developing CNS in vivo, we will concentrate on one experimental model that has examined the impact of the dietary absence of vitamin D in utero. Finally, we discuss the epidemiological data that suggests that vitamin D deficiency either in utero or in early life may have adverse neuropsychiatric implications.

Infection with the wMel and wMelPop strains of Wolbachia leads to higher levels of melanization in the hemolymph of Drosophila melanogaster, Drosophila simulans and Aedes aegypti

Introduction of the life-shortening strain of Wolbachia pipientis, wMelPop, into the key dengue vector, Aedes aegypti, and the anti-pathogen effects in Wolbachia-infected hosts highlights the need for more research into its interactions with its original host, Drosophila melanogaster, and the novel mosquito host. The visual difference in darkness between the eggs of wMelPop Wolbachia-infected and uninfected mosquito hosts after egg deposition led to further investigation into melanization levels of the insects. Both D. melanogaster and A. aegypti infected with wMelPop showed increased levels of melanization, especially in females. This result was also seen in D. melanogaster and Drosophila simulans infected with the closely related wMel strain. D. simulans infected with other strains of Wolbachia did not display this difference. HPLC analysis of hemolymph from mosquitoes showed that this difference was not due to dopamine levels in the host as they were no different in wMelPop-infected and control mosquitoes before or after blood feeding.

Developmental Vitamin D Deficiency (DVD) and Brain Dopamine Ontogeny

Our group has pioneered research indicating that Developmental vitamin D (DVD) deficiency (a candidate risk factor for schizophrenia) alters both brain development and function. We have convergent evidence indicating a disturbance in dopamine signalling in this model. 1stly the superior colliculus (the proto-basal ganglia) is the initial site where the vitamin D receptor is expressed in foetal brain; 2ndly we show a reduction in Catechol-O-methyl transferase (a major metabolic enzyme for dopamine) in these foetal brains; 3rdly dopamine metabolites in the DVD deplete neonatal brain reflect this enzymatic change. When we allow these animals to mature under vitamin D normal conditions we repeatedly observe alterations in both spontaneous and psychomimetic enhanced locomotion. Consistent with the theme of persistent changes in dopamine signalling in this model we now present new data showing that dopamine transporter density and/or affinity are altered in DVD deplete female offspring whilst DA 1 receptor density and dopamine cell number are reduced in DVD deplete male offspring (all P< 0.05 n>8).

Our most recent studies indicate that Nurr-1, a nuclear transcription regulator important in both bone and dopamine neuron development and survival may be a molecular mediator of these processes. Nurr-1 is upregulated by parathyroid hormone (PTH). PTH levels are 2-3 fold greater in vitamin D deficient Dams across gestation. Most importantly we have just shown that Nurr-1 is dose-dependently upregulated by parathyroid hormone (PTH) in a neuroblastoma cell line.

Conclusions:

Our findings strongly suggest that vitamin D directly (or indirectly via PTH) mediates dopamine neuron development.

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.

The impact of nonlinear exposure-risk relationships on seasonal time-series data: modelling Danish neonatal birth anthropometric data

Background

Birth weight and length have seasonal fluctuations. Previous analyses of birth weight by latitude effects identified seemingly contradictory results, showing both 6 and 12 monthly periodicities in weight. The aims of this paper are twofold: (a) to explore seasonal patterns in a large, Danish Medical Birth Register, and (b) to explore models based on seasonal exposures and a non-linear exposure-risk relationship.

Methods

Birth weight and birth lengths on over 1.5 million Danish singleton, live births were examined for seasonality. We modelled seasonal patterns based on linear, U- and J-shaped exposure-risk relationships. We then added an extra layer of complexity by modelling weighted population-based exposure patterns.

Results

The Danish data showed clear seasonal fluctuations for both birth weight and birth length. A bimodal model best fits the data, however the amplitude of the 6 and 12 month peaks changed over time. In the modelling exercises, U- and J-shaped exposure-risk relationships generate time series with both 6 and 12 month periodicities. Changing the weightings of the population exposure risks result in unexpected properties. A J-shaped exposure-risk relationship with a diminishing population exposure over time fitted the observed seasonal pattern in the Danish birth weight data.

Conclusion

In keeping with many other studies, Danish birth anthropometric data show complex and shifting seasonal patterns. We speculate that annual periodicities with non-linear exposure-risk models may underlie these findings. Understanding the nature of seasonal fluctuations can help generate candidate exposures.

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.

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.

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.

Maternal vitamin D3 deprivation and the regulation of apoptosis and cell cycle during rat brain development

Recently, it has been shown that the prenatal vitamin D(3) depletion is associated with altered brain development. Given the antiproliferative and pro-apoptotic properties of vitamin D(3) in various cell types, we examined the effects of maternal vitamin D(3) deprivation on cell proliferation and apoptosis within the rat cortex at several developmental stages. Our results confirm that vitamin D(3) regulates these processes in the developing brain at both cellular and molecular levels. Compared to control animals, the embryos and pups from vitamin D(3) depleted mothers had significantly less apoptotic cells, this finding being most pronounced at birth. Additionally, there were significantly more mitotic cells but this was not associated with any particular developmental period. Targeted gene arrays specific for apoptosis and cell cycle genes confirmed a pattern of transcription deregulation in the deplete group consistent with the known properties of vitamin D(3). While most current vitamin D(3) research is focussed on the pro-apoptotic and prodifferentiating properties of vitamin D(3) as adjuncts for the treatment of cancers, our findings highlight the important role that this hormone plays in normal development via these same properties specifically in the brain.

Schizophrenia, vitamin D, and brain development

Schizophrenia research is invigorated at present by the recent discovery of several plausible candidate susceptibility genes identified from genetic linkage and gene expression studies of brains from persons with schizophrenia. It is a current challenge to reconcile this gathering evidence for specific candidate susceptibility genes with the "neurodevelopmental hypothesis," which posits that schizophrenia arises from gene-environment interactions that disrupt brain development. We make the case here that schizophrenia may result not from numerous genes of small effect, but a few genes of transcriptional regulation acting during brain development. In particular we propose that low vitamin D during brain development interacts with susceptibility genes to alter the trajectory of brain development, probably by epigenetic regulation that alters gene expression throughout adult life. Vitamin D is an attractive "environmental" candidate because it appears to explain several key epidemiological features of schizophrenia. Vitamin D is an attractive "genetic" candidate because its nuclear hormone receptor regulates gene expression and nervous system development. The polygenic quality of schizophrenia, with linkage to many genes of small effect, maybe brought together via this "vitamin D hypothesis." We also discuss the possibility of a broader set of environmental and genetic factors interacting via the nuclear hormone receptors to affect the development of the brain leading to schizophrenia.

Low maternal vitamin D as a risk factor for schizophrenia: a pilot study using banked sera

OBJECTIVE

Evidence from epidemiology suggests that low maternal vitamin D may be a risk factor for schizophrenia.

METHOD

Based on sera taken during the third trimester, we compared the level of 25 hydroxyvitamin D3 in mothers of individuals with schizophrenia or schizoaffective disorders versus mothers of unaffected controls. For each case, we selected two controls matched on race, gender and date of birth of the offspring.

RESULTS

There was no significant difference in third trimester maternal vitamin D in the entire sample (cases = 26, controls = 51). Within the subgroup of black individuals (n = 21), there was a trend level difference in the predicted direction.

CONCLUSIONS

Maternal vitamin D does not operate as a continuous graded risk factor for schizophrenia, however, the results in the black subgroup raise the possibility that below a certain critical threshold, low levels of maternal vitamin D may be associated with an increased risk of schizophrenia.

Vitamin D3 and brain development

Evidence for the presence of the vitamin D receptor in brain implies this vitamin may have some function in this organ. This study investigates whether vitamin D(3) acts during brain development. We demonstrate that rats born to vitamin D(3)-deficient mothers had profound alterations in the brain at birth. The cortex was longer but not wider, the lateral ventricles were enlarged, the cortex was proportionally thinner and there was more cell proliferation throughout the brain. There were reductions in brain content of nerve growth factor and glial cell line-derived neurotrophic factor and reduced expression of p75(NTR), the low-affinity neurotrophin receptor. Our findings would suggest that low maternal vitamin D(3) has important ramifications for the developing brain.

Effects of nifedipine on psychosis and tardive dyskinesia in schizophrenic patients

In an open label study, two fixed doses of nifedipine (30 mg and 60 mg daily) were added to the usual antipsychotic drug treatments of 10 patients suffering from chronic schizophrenia. While no patient experienced significant improvements, statistically significant falls in Brief Psychiatric Rating Scales scores were observed. A significant reduction in Abnormal Involuntary Movement Scale scores was observed in those patients with tardive dyskinesia. After the addition of nifedipine, four of the 10 patients showed large increases in plasma neuroleptic activity (radioreceptor assay) that decreased to baseline levels within two weeks. The possibility that this represents competitive inhibition and subsequent induction of the liver metabolism of the antipsychotic drugs is discussed. Adverse effects encountered are also discussed.