Developmental Vitamin D Deficiency in the Rat Impairs Recognition Memory, but Has No Effect on Social Approach or Hedonia

Cholecalciferol Supplementation Impacts Behavior and Hippocampal Neuroglial Reorganization in Vitamin D-Deficient Rats

Vitamin D deficiency (VDD) is widespread around the world and has been extensively documented to affect various health conditions, including the cognitive functioning of the brain. Serum 25-hydroxylated forms of vitamin D are traditionally used to determine vitamin D status. However, there is now evidence that cholecalciferol activation can occur and be controlled by locally expressed enzymes in the brain. This study aimed to investigate the effects of cholecalciferol supplementation on cognitive function in rats who underwent transient VDD in adulthood. Thirty-six adult Wistar rats were administered paricalcitol (seven doses of 32 ng injected every other day) along with a "vitamin D-free" diet to induce VDD, which was confirmed using a LC-MS/MS serum analysis of the cholecalciferol and 25-hydroxyvitamin D3 levels. Treatment was performed by including 1000 IU/kg and 10,000 IU/kg cholecalciferol in the diet. Cognitive performance was evaluated using the novel object recognition (NOR), Morris water maze (MWM), and radial arm maze (RAM) tests. An immunohistochemical analysis of the brain regions involved in learning and memory was performed by quantifying the neurons, astrocytes, and microglia labelled with anti-neuronal nuclei (NeuN), glial fibrillary acidic protein (GFAP), and ionized calcium-binding adaptor molecule 1 (Iba-1) antibodies, respectively. The vitamin D deficient group showed the lowest performance in both the MWM and RAM tests. In contrast, the cholecalciferol-treated groups exhibited a faster learning curve. However, no difference was detected between the groups in the NOR test. On the other hand, differences in the cellular organization of the hippocampus and amygdala were observed between the groups. Cholecalciferol supplementation decreased the density of the Iba-1- and GFAP-labeled cells in the hilus and cornu Ammonis 3 (CA3) regions of the hippocampus and in the amygdala. These results support vitamin D's substantial role in learning and memory. They also highlight that subtle changes of cognitive function induced by transient VDD could be reversed by cholecalciferol supplementation. Further studies are needed to better understand VDD and cholecalciferol's effects on the brain structure and function.

Nurturing development: how a mother's nutrition shapes offspring's brain through the gut

Pregnancy is a transformative period marked by profound physical and emotional changes, with far-reaching consequences for both mother and child. Emerging research has illustrated the pivotal role of a mother's diet during pregnancy in influencing the prenatal gut microbiome and subsequently shaping the neurodevelopment of her offspring. The intricate interplay between maternal gut health, nutrition, and neurodevelopmental outcomes has emerged as a captivating field of investigation within developmental science. Acting as a dynamic bridge between mother and fetus, the maternal gut microbiome, directly and indirectly, impacts the offspring's neurodevelopment through diverse pathways. This comprehensive review delves into a spectrum of studies, clarifying putative mechanisms through which maternal nutrition, by modulating the gut microbiota, orchestrates the early stages of brain development. Drawing insights from animal models and human cohorts, this work underscores the profound implications of maternal gut health for neurodevelopmental trajectories and offers a glimpse into the formulation of targeted interventions able to optimize the health of both mother and offspring. The prospect of tailored dietary recommendations for expectant mothers emerges as a promising and accessible intervention to foster the growth of beneficial gut bacteria, potentially leading to enhanced cognitive outcomes and reduced risks of neurodevelopmental disorders.

Vitamin D is associated with visual memory in young northern adolescents

BACKGROUND

Vitamin D status has been linked to visual memory in adults. We hypothesized a similar association in young adolescents.

METHODS

Participants were 9-13 years. The Rey-Osterrieth Complex Figure Task (ROCF), Rey Auditory Verbal Learning Task (RAVLT), Digit Span (Forward, Backward), and verbal fluency task assessed visual and verbal learning/memory, attention/working memory, and executive functioning/language, respectively. An at-home, mail-in blood spot test assessed 25(OH)D levels.

RESULTS

Participants (N = 56) were 10.7 ± 1.3 years, 61% females, 25(OH)D levels 84.2 ± 25 nmol/L(39.9 - 167.2 nmol/L) and 41% had insufficient vitamin D status (<75 nmol/L). Only measures of visual memory (ROCF-Recall, -%Recall of Copy) were significantly correlated with 25(OH)D, r = .34, p < .01 and r = .33, p < .01, respectively, and 25(OH)D remained a significant independent predictor on multiple regression analyses, which included age and sex.(ROCF-Recall overall model: Adj R2 = .24, p < .001; for 25(OH)D: p = .009; ROCF-%Recall of Copy overall model: Adj R2 = .20 p < .002; for 25(OH)D: p = .01). Individuals with sufficient vitamin D performed significantly better only on these measures (t-tests; ROCF-Recall, p = .016, d = 0.68; ROCF-%Recall of Copy, p = .022, d = 0.64). Despite moderate effect sizes (d = 0.4-0.5) in the Younger Age Group (9-10 years), only in the Older Age Group (11-13 years) was 25(OH)D significantly correlated with ROCF-Recall, r = .64, p = .0001 and ROCF-%Recall of Copy, r = .64, p = .0001, as well as working memory (Digit Span-Backward), Spearman's r = .46, p = .013. Similarly, those in the Older Age Group with sufficient vitamin D performed significantly better on ROCF-Recall, p = .01, d = 1.07; and ROCF-%Recall of Copy, p = .009, d = 1.08.

CONCLUSIONS

Vitamin D insufficiency was common in young adolescents. Similar to adults, visual memory was better among participants with higher 25(OH)D and those with sufficient levels. This effect was especially pronounced among older participants, suggesting possible time- and/or age-related implications of vitamin D status on cognition.

Maternal and neonatal blood vitamin D status and neurodevelopment at 24 months of age: a prospective birth cohort study

BACKGROUND

This study aimed to explore the relationship of 25-hydroxyvitamin D [25(OH)D] in three trimesters and at birth with neurodevelopment at 24 months of age.

METHODS

From 2013 to 2016, pregnant women from the Shanghai Birth Cohort in China were recruited for the study. Altogether, 649 mother-infant pairs were included. Serum 25(OH)D was measured with mass spectrometry in three trimesters, and cord blood was divided into deficiency (< 20 and < 12 ng/mL, respectively), insufficiency (20-30 and 12-20 ng/mL, respectively), and sufficiency (≥ 30 and ≥ 20 ng/mL, respectively). Bayley-III scale was used to assess cognitive, language, motor, social-emotional, and adaptive behavior development at 24 months of age. The Bayley-III scores were grouped into quartiles, and scores within the lowest quartile were defined as suboptimal development.

RESULTS

After adjusting for confounding factors, cord blood 25(OH)D in the sufficient group was positively correlated with cognitive [β = 11.43, 95% confidence interval (CI) = 5.65-17.22], language (β = 6.01, 95% CI = 1.67-10.3), and motor scores (β = 6.43, 95% CI = 1.73-11.1); cord blood 25(OH)D in the insufficient group was also positively correlated with cognitive scores (β = 9.42, 95% CI = 3.74-15.11). Additionally, sufficient vitamin D status in the four periods and persistent 25(OH)D ≥ 30 ng/mL throughout pregnancy were associated with a lower risk of suboptimal cognitive development in adjusted models, although the effects were attenuated after applying the false discovery rate adjustment.

CONCLUSIONS

Cord blood 25(OH)D ≥ 12 ng/mL has a significant positive association with cognitive, language, and motor development at 24 months of age. Sufficient vitamin D status in pregnancy might be a protective factor for suboptimal neurocognition development at 24 months of age.

Developmental Manipulation-Induced Changes in Cognitive Functioning

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

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

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

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

BACKGROUND

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

METHODS AND RESULTS

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

CONCLUSION

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

Role of Vitamin D in Cognitive Dysfunction: New Molecular Concepts and Discrepancies between Animal and Human Findings

PURPOSE OF REVIEW

increasing evidence suggests that besides the several metabolic, endocrine, and immune functions of 1alpha,25-dihydroxyvitamin D (1,25(OH)2D), the neuronal effects of 1,25(OH)2D should also be considered an essential contributor to the development of cognition in the early years and its maintenance in aging. The developmental disabilities induced by vitamin D deficiency (VDD) include neurological disorders (e.g., attention deficit hyperactivity disorder, autism spectrum disorder, schizophrenia) characterized by cognitive dysfunction. On the other hand, VDD has frequently been associated with dementia of aging and neurodegenerative diseases (e.g., Alzheimer's, Parkinson's disease).

RECENT FINDINGS

various cells (i.e., neurons, astrocytes, and microglia) within the central nervous system (CNS) express vitamin D receptors (VDR). Moreover, some of them are capable of synthesizing and catabolizing 1,25(OH)2D via 25-hydroxyvitamin D 1alpha-hydroxylase (CYP27B1) and 25-hydroxyvitamin D 24-hydroxylase (CYP24A1) enzymes, respectively. Both 1,25(OH)2D and 25-hydroxyvitamin D were determined from different areas of the brain and their uneven distribution suggests that vitamin D signaling might have a paracrine or autocrine nature in the CNS. Although both cholecalciferol and 25-hydroxyvitamin D pass the blood-brain barrier, the influence of supplementation has not yet demonstrated to have a direct impact on neuronal functions. So, this review summarizes the existing evidence for the action of vitamin D on cognitive function in animal models and humans and discusses the possible pitfalls of therapeutic clinical translation.

Malnutrition and the microbiome as modifiers of early neurodevelopment

Malnutrition refers to a dearth, excess, or altered differential ratios of calories, macronutrients, or micronutrients. Malnutrition, particularly during early life, is a pressing global health and socioeconomic burden that is increasingly associated with neurodevelopmental impairments. Understanding how perinatal malnutrition influences brain development is crucial to uncovering fundamental mechanisms for establishing behavioral neurocircuits, with the potential to inform public policy and clinical interventions for neurodevelopmental conditions. Recent studies reveal that the gut microbiome can mediate dietary effects on host physiology and that the microbiome modulates the development and function of the nervous system. This review discusses evidence that perinatal malnutrition alters brain development and examines the maternal and neonatal microbiome as a potential contributing factor.

Protective effects of vitamin D on learning and memory deficit induced by scopolamine in male rats: the roles of brain-derived neurotrophic factor and oxidative stress

The beneficial effects of vitamin D (vit D) on central nervous system disorders have been suggested. In the current research, the protective effects of vit D on learning and memory deficit induced by scopolamine, oxidative stress criteria, brain-derived neurotrophic factor (BDNF), and nitric oxide (NO) in the brain were investigated. Rats were divided into five groups, including (1) Control, (2) Scopolamine (2 mg/kg), (3-5) Scopolamine + Vit D (100, 1000, and 10,000 IU/kg) groups. Vit D administrated for 2 weeks and in the third week scopolamine co-administrated with vit D and behavioral tests, including Morris water maze (MWM) and passive avoidance (PA) tests, were carried out. The cortical and hippocampal tissues were analyzed for BDNF, catalase (CAT), and superoxide dismutase (SOD) activities, thiol content, NO metabolites, and malondialdehyde (MDA) concentration. Scopolamine injection significantly impaired rats' performance on the MWM and PA test. It further enhanced the MDA and nitrite level while decreased thiol content and BDNF levels and SOD and CAT activities in the brain. Administration of both 1000 and 10,000 IU/kg vit D improved cognitive outcome in MWM and PA tests. In addition, vit D elevated thiol content, SOD and CAT activities, and BDNF levels, while reduced nitrite and MDA concentration. Vit D also increased the levels of vit D and calcium in the serum. The results demonstrated that vit D has protective effects on scopolamine-associated learning and memory impairment by improving BDNF levels and attenuating NO and brain tissue oxidative damage.

Vitamin D and schizophrenia: 20 years on

Many epidemiological studies have highlighted the link between vitamin D deficiency and schizophrenia. In particular, two prominent studies report an association between neonatal vitamin D deficiency and an increased risk of schizophrenia. In parallel, much has been learnt about the role of vitamin D in the developing central nervous system over the last two decades. Studies in rodent models of developmental vitamin D (DVD)-deficiency describe how brain development is altered leading to a range of neurobiological and behavioral phenotypes of interest to schizophrenia. While glutamate and gamma aminobutyric acid (GABA) systems have been little investigated in these models, alterations in developing dopamine systems are frequently reported. There have been far more studies reporting patients with schizophrenia have an increased risk of vitamin D deficiency compared to well controls. Here we have conducted a systematic review and meta-analysis that basically confirms this association and extends this to first-episode psychosis. However, patients with schizophrenia also have poorer general health, poorer diets, are frequently less active and also have an increased risk of other medical conditions, all factors which reduce circulating vitamin D levels. Therefore, we would urge caution in any causal interpretation of this association. We also summarize the inconsistent results from existing vitamin D supplementation trials in patients with schizophrenia. In respect to animal models of adult vitamin D deficiency, such exposures produce subtle neurochemical alterations and effects on cognition but do not appear to produce behavioral phenotypes of relevance to schizophrenia. We conclude, the hypothesis that vitamin D deficiency during early life may increase the risk of schizophrenia remains plausible and warrants ongoing research.

Vitamin D: Brain and Behavior

It has been 20 years since we first proposed vitamin D as a "possible" neurosteroid.^{( 1 )} Our work over the last two decades, particularly results from our cellular and animal models, has confirmed the numerous ways in which vitamin D differentiates the developing brain. As a result, vitamin D can now confidently take its place among all other steroids known to regulate brain development.^{( 2 )} Others have concentrated on the possible neuroprotective functions of vitamin D in adult brains. Here these data are integrated, and possible mechanisms outlined for the various roles vitamin D appears to play in both developing and mature brains and how such actions shape behavior. There is now also good evidence linking gestational and/or neonatal vitamin D deficiency with an increased risk of neurodevelopmental disorders, such as schizophrenia and autism, and adult vitamin D deficiency with certain degenerative conditions. In this mini-review, the focus is on what we have learned over these past 20 years regarding the genomic and nongenomic actions of vitamin D in shaping brain development, neurophysiology, and behavior in animal models. © 2020 The Author. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.