Non-Skeletal Activities of Vitamin D: From Physiology to Brain Pathology

The association of vitamin deficiency with depression risk in late-life depression: a review

Late-life depression (LLD), a growing public health challenge in aging societies, profoundly impacts physical and mental health by exacerbating cognitive decline, functional disability, and comorbid chronic diseases. Emerging research highlights vitamin supplementation as a promising adjunctive therapy for LLD, targeting its multifactorial pathogenesis involving mitochondrial dysfunction, neuroinflammation, and oxidative stress. Specific vitamins, including B-complex vitamins (B1, B6, B9, B12), vitamin D, and antioxidants (C, E), demonstrate therapeutic potential through mechanisms ranging from neurotransmitter regulation to mitochondrial function enhancement. For instance, vitamin D modulates serotonin synthesis and calcium signaling, while B vitamins mitigate homocysteine-mediated neurotoxicity and support energy metabolism. Antioxidants counteract neural oxidative damage linked to depressive severity. Clinical studies reveal that vitamin D deficiency (<20 ng/mL) correlates with elevated depression risk, and combined B-vitamin supplementation shows symptom alleviation in nutritionally deficient subgroups. However, evidence remains heterogeneous due to variability in dosing protocols, bioavailability, and population-specific factors like comorbidities. Despite growing evidence, critical gaps persist regarding optimal dosages, bioavailability variations, and long-term outcomes in elderly populations. This review synthesizes current evidence on vitamin-mediated cellular pathways in LLD management, evaluates clinical efficacy across interventions, and proposes personalized nutritional strategies to optimize therapeutic outcomes. By integrating mechanistic insights with clinical data, this analysis aims to guide evidence-based vitamin supplementation protocols for LLD within geriatric care frameworks.

Early disruptions in vitamin D receptor signaling induces persistent developmental behavior deficits in zebrafish larvae

A critical function of the nervous system is to rapidly process sensory information and initiate appropriate behavioral responses. Defects in sensory processing and behavior selection are commonly observed in neuro-psychiatric conditions including anxiety, autism (ASD), and schizophrenia. The etiology of sensory processing disorders remains equivocal; however, it is hypothesized that extrinsic environmental factors can play fundamental roles. In this study we examine the importance of vitamin D (1α, 25-dihydroxyvitamin D3) receptor signaling during early life stage development on sensory processing and neurobehavioral health outcomes. While vitamin D has traditionally been associated with mineral ion homeostasis, accumulating evidence suggests non-calcemic roles for vitamin D including early neurodevelopment. Here we demonstrate that systemic disruption of vitamin D receptor (VDR) signaling with a conditional dominant negative (dnVDR) transgenic zebrafish line results in specific visual and acoustic sensorimotor behavior defects. Induction of dnVDR between 24-72 hours post fertilization (hpf) results in modulation of visual motor response with demonstrate attenuation in acute activity and hypolocomotion across multiple swimming metrics when assayed at 6- and 28-days post fertilization (dpf). Disruption in VDR signaling additionally resulted in a strong and specific attenuation of the Long-Latency C-bends (LLC) within the acoustic startle response at 6 dpf while Short-Latency C-bends (SLC) were moderately impacted. Pre-pulse inhibition (PPI) was not impacted in young larvae however exhibited a significantly attenuated response at 28 dpf suggesting an inability to properly modulate their startle responses later in development and persistent effects of VDR modulation during early development. Overall, our data demonstrate that modulation of vitamin D signaling during critical windows of development irreversibly disrupts the development of neuronal circuitry associated with sensory processing behaviors which may have significant implications to neurobehavioral health outcomes.

Effects of vitamin D on brain function in preschool children with autism spectrum disorder: a resting-state functional MRI study

BACKGROUND

Previous studies indicate vitamin D impacts autism spectrum disorder (ASD), but its relationship with brain function is unclear. This study investigated the association between serum 25-hydroxyvitamin D [25(OH)D] levels and brain function in preschool children with ASD using resting-state functional magnetic resonance imaging (rs-fMRI), and explored correlations with clinical symptoms.

METHODS

A total of 226 ASD patients underwent rs-fMRI scanning and serum 25(OH)D testing. Clinical symptoms were assessed using Childhood Autism Rating Scale (CARS) and Autism Behavior Checklist (ABC). Patients were categorized into mild and severe groups based on the CARS, and further divided into normal (NVD), insufficient (VDI), and deficient (VDD) serum 25(OH)D levels. Changes in brain function among these groups were analyzed using regional homogeneity (ReHo), with ABC scores used for correlation analysis.

RESULTS

In mild ASD, ReHo increased in the right postcentral gyrus and left precuneus in the VDI and VDD groups compared to NVD, and decreased in the bilateral middle cingulate gyrus and left superior frontal gyrus in the VDD group compared to VDI. In severe ASD, ReHo decreased in the right middle occipital gyrus and increased in the right insula in the VDI group compared to NVD, and increased in the right superior frontal gyrus in the VDD group compared to VDI. Correlation analysis revealed that in mild ASD, ReHo in the right postcentral gyrus was positively correlated with body and object use scores in the NVD and VDI groups, while ReHo in the right middle cingulate gyrus was negatively correlated with relating scores in the VDD and VDI groups. In severe ASD, ReHo in the right insula was positively correlated with language scores in the NVD and VDI groups.

CONCLUSIONS

ASD patients with lower serum 25(OH)D levels show multiple brain functional abnormalities, with specific brain region alterations linked to symptom severity. These findings enhance our understanding of vitamin D's impact on ASD and suggest that future research may explore its therapeutic potential.

Baseline Vitamin D Levels on Quality of Life and Pain Perception Among Patients with Chronic Pain with Long-Term Prescription Opioid Use: A Prospective Study

Objectives: To investigate the correlation between baseline serum concentrations of 25-hydroxyvitamin D (25-OHD) and quality of life (QoL), as well as pain perception in patients with chronic pain with long-term prescription opioid usage before opioid detoxification. Methods: We prospectively studied 45 patients with chronic pain with long-term prescription opioid usage who were selected for elective detoxification. Baseline serum 25-OHD levels were measured prior to detoxification, classifying patients as either vitamin D deficient (<75 nmol/L) or sufficient (≥75 nmol/L). QoL was assessed using the SF-36v2TM questionnaire, while pain levels were assessed using Visual Analogue Scale (VAS) scores before treatment. Results: Mean pain scores before detoxification of the patients with sufficient baseline 25-OHD levels vs. those with deficient levels were, respectively, 6.06 ± 2.32 vs. 6.86 ± 2.10 (normalized scores 1.22 ± 0.571 vs. 0.950 ± 0.632; p = 0.164). The analysis of SF-36v2™ questionnaire scores revealed minimal variation between groups (35.00 ± 14.198 vs. 34.97 ± 13.52), indicating no significant association between Vitamin D levels and QoL (p = 0.913). Conclusions: The analysis of baseline 25-OHD levels in relation to QoL assessments and pain scores did not reveal a statistically significant association, indicating that variations in baseline vitamin D levels may not substantially impact QoL or pain perception. Further studies may help determine how to assess and optimize vitamin D levels in patients with chronic pain on long-term prescription opioids.

First Sila-Vitamin D Analogues: Design, Synthesis, Structural Analysis and Biological Activity

The incorporation of silicon bioisosteres into pharmacological structures has been used as a strategy to improve the therapeutic potential of drugs. However, no secosteroidal silicon-containing VDR ligands have been developed. Here we report the design, synthesis, and biological activity of six analogues of the natural hormone 1,25-dihydroxyvitamin D3 (1,25D3), which incorporate a silicon atom as a side chain-C25 isostere. The analogues were synthesized by the Wittig-Horner approach starting from Inhoffen-Lythgoe diol. The crystal structures of the complexes formed by the sila-analogues with the ligand binding domain of VDR revealed additional interactions of the sila-containing side chains that stabilize the VDR active conformation. These sila-analogues show similar VDR binding and transcriptional activity in comparison with the natural hormone 1,25D3, but with significantly less hypercalcemic activity. The new analogues, when combined with chemotherapy, significantly decrease cell proliferation.

Vitamin D and focal brain atrophy in PD with non-dementia: a VBM study

Background

The status of vitamin D has been proposed to have an impact on cognition. Gray matter volume (GMV) is a potential marker of cognitive function. We investigated whether lower serum 25-hydroxyvitamin D level was associated with reduced cerebral GMV in Parkinson's disease with non-dementia (PDND) patients.

Methods

Baseline neuropsychiatric performance and serum 25-hydroxyvitamin D levels were examined in 24 PDND patients and 24 healthy controls (HCs). A set of cognitive scales were used to evaluate the cognition. Voxel-based morphometry (VBM) was performed to calculate each PDND patient's GMV, based on structural magnetic resonance imaging data. Associations between serum 25-hydroxyvitamin D levels, cognition, and GMV were evaluated.

Results

The serum 25-hydroxyvitamin D levels of the PDND group were significantly lower than those of the HC group. The simple linear regression analyses between serum 25-hydroxyvitamin D levels and the scores of subtests that analyzed cognitive function showed that serum 25-hydroxyvitamin D levels were negatively correlated with Trail Making Test-A scores and positively correlated with Symbol Digit Modalities Test and Auditory Verbal Learning Test scores. Multiple regression analyses revealed a positive correlation between the right fusiform gyrus GMV and serum 25-hydroxyvitamin D levels.

Conclusion

We hypothesized that the lower serum 25-hydroxyvitamin D level in patients with PDND might affect auditory word learning and spatial cognition ability by reducing the gray matter volume of the right fusiform gyrus, thereby leading to deterioration of semantic understanding and memory function.

Vitamin D Deficiency Does Not Affect Cognition and Neurogenesis in Adult C57Bl/6 Mice

Vitamin D deficiency is a global problem. Vitamin D, the vitamin D receptor, and its enzymes are found throughout neuronal, ependymal, and glial cells in the brain and are implicated in certain processes and mechanisms in the brain. To investigate the processes affected by vitamin D deficiency in adults, we studied vitamin D deficient, control, and supplemented diets over 6 weeks in male and female C57Bl/6 mice. The effect of the vitamin D diets on proliferation in the neurogenic niches, changes in glial cells, as well as on memory, locomotion, and anxiety-like behavior, was investigated. Six weeks on a deficient diet was adequate time to reach deficiency. However, vitamin D deficiency and supplementation did not affect proliferation, neurogenesis, or astrocyte changes, and this was reflected on behavioral measures. Supplementation only affected microglia in the dentate gyrus of female mice. Indicating that vitamin D deficiency and supplementation do not affect these processes over a 6-week period.

Co-administration of probiotics and vitamin D reduced disease severity and complications in patients with Parkinson's disease: a randomized controlled clinical trial

RATIONALE

Probiotics have beneficial effects on the nervous system by modulating the gut-brain axis. Additionally, vitamin D supplementation presents a potential way for ameliorating neuropsychological disorders, particularly in regions with a high prevalence of vitamin D deficiency.

OBJECTIVES

The current clinical trial aimed to investigate the role of co-administered supplementation of probiotics and Vitamin D on the different inflammatory aspects of patients with Parkinson's disease.

METHODS

Forty-six patients with PD were recruited From the Functional Neurosurgery Research Center, Tehran, Iran. These patients were randomly allocated to one of the two treatment groups: Group A, who received probiotic/vitamin D supplements (n = 23), and Group B who received placebo capsules (n = 23) for 12 weeks. As primary outcomes, Interferon-Gamma (IFN-γ), interleukin 1 beta (IL-1β), IL-6, IL-10, Tumor Necrosis Factor-Alpha (TNF-α), total antioxidant capacity (TAC), and malondialdehyde (MDA) in serum were evaluated at the baseline and the end of the trial. Moreover, Additional questionnaire-based factors including gastrointestinal symptom rating scale (GSRS), Beck Anxiety Inventory (BAI), and Unified Parkinson's Disease Rating Scale (UPDRS) were evaluated.

RESULTS

Our findings demonstrated that the consumption of probiotic/vitamin D supplements leads to a significant decrease in IL-1β, INF-γ, IL-6, and MDA levels, while showing a significant increase in IL-10 and TAC levels compared to the placebo group (P < 0.05). Additionally, it leads to a significant decrease in the disease severity, anxiety, and gastrointestinal problems in PD patients in comparison to the placebo group (P < 0.05).

CONCLUSIONS

Given the acknowledged role of inflammation in the pathogenesis of Parkinson's disease on one hand, and the recognized anti-inflammatory and antioxidant effects associated with probiotics and vitamin D on the other hand, the concurrent administration of probiotics and vitamin D supplements emerges as a promising and potentially effective treatment option for individuals with PD.

Tremendous Fidelity of Vitamin D3 in Age-related Neurological Disorders

Vitamin D3 (VD) is a secosteroid hormone and shows a pleiotropic effect in brain-related disorders where it regulates redox imbalance, inflammation, apoptosis, energy production, and growth factor synthesis. Vitamin D3's active metabolic form, 1,25-dihydroxy Vitamin D3 (1,25(OH)2D3 or calcitriol), is a known regulator of several genes involved in neuroplasticity, neuroprotection, neurotropism, and neuroinflammation. Multiple studies suggest that VD deficiency can be proposed as a risk factor for the development of several age-related neurological disorders. The evidence for low serum levels of 25-hydroxy Vitamin D3 (25(OH)D3 or calcidiol), the major circulating form of VD, is associated with an increased risk of Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD), dementia, and cognitive impairment. Despite decades of evidence on low VD association with neurological disorders, the precise molecular mechanism behind its beneficial effect remains controversial. Here, we will be delving into the neurobiological importance of VD and discuss its benefits in different neuropsychiatric disorders. The focus will be on AD, PD, and HD as they share some common clinical, pathological, and epidemiological features. The central focus will be on the different attributes of VD in the aspect of its anti-oxidative, anti-inflammatory, anti-apoptotic, anti-cholinesterase activity, and psychotropic effect in different neurodegenerative diseases.

The neuroprotective effect of vitamin D in Parkinson's disease: association or causation

Parkinson's disease (PD) is a chronic neurodegenerative disease (NDD) due to the degeneration of dopaminergic neurons (DNs) in the substantia nigra (SN). PD is characterized by diverse motor symptoms such as rigidity, resting tremors, and bradykinesia, and non-motor symptoms such as cognitive dysfunction and sleep disturbances. Vitamin D (VD), VD receptor (VDR), and VD metabolites are present in the brain and play a role in maintaining the development, differentiation, and functions of the DNs. VDRs exert protective effects against PD neuropathology by modulating functional capacity and DNs neurotransmission in the SN. In virtue of its anti-inflammatory and antioxidant activities, VD could be effective in the prevention and treatment of PD. VD exerts a neuroprotective effect by reducing oxidative stress and mitochondrial dysfunction, and by increasing autophagy and brain-derived neurotrophic factor (BDNF). Low VD serum level is connected with cognitive dysfunction and the development of dementia in PD. The VD-mediated cognitive augmenting effect is interrelated to the safeguarding of synaptic plasticity and modulation of neurotransmitter release. VD deficiency is linked with the severity of olfactory dysfunction which precedes the progression of symptomatic PD. However, the precise role of VD in PD remains unidentified, and there is a conflict about whether treatment with VD can ameliorate PD or not.

Vitamin D in Central Nervous System: Implications for Neurological Disorders

Vitamin D, obtained from diet or synthesized internally as cholecalciferol and ergocalciferol, influences bodily functions through its most active metabolite and the vitamin D receptor. Recent research has uncovered multiple roles for vitamin D in the central nervous system, impacting neural development and maturation, regulating the dopaminergic system, and controlling the synthesis of neural growth factors. This review thoroughly examines these connections and investigates the consequences of vitamin D deficiency in neurological disorders, particularly neurodegenerative diseases. The potential benefits of vitamin D supplementation in alleviating symptoms of these diseases are evaluated alongside a discussion of the controversial findings from previous intervention studies. The importance of interpreting these results cautiously is emphasised. Furthermore, the article proposes that additional randomised and well-designed trials are essential for gaining a deeper understanding of the potential therapeutic advantages of vitamin D supplementation for neurological disorders. Ultimately, this review highlights the critical role of vitamin D in neurological well-being and highlights the need for further research to enhance our understanding of its function in the brain.

Assessment of Vitamin D Status in the Drâa-Tafilalet Population (Morocco) Based on Sociodemographic, Health, and Nutritional Factors

The purpose of this study was to evaluate the vitamin D status and determine the factors influencing it in the Drâa-Tafilalet community (southeastern Morocco). Sociodemographic factors, health, cognitive status, sun exposure, and nutritional conditions were examined to help us understand their association with vitamin D status. Vitamin D data were gathered through laboratory testing, while demographic and health information was collected through interviews with participants in 2023. The study involved 100 participants aged 60 and above, most of whom were women (85%) rather than men (15%). The majority of participants were Arabs (90%), with a minority being Amazigh (10%). The average vitamin D level was 31.83 ± 10.55 ng/mL, varying based on participants' age, education, and gender. Sun-exposed individuals exhibited significantly higher mean vitamin D levels (33.56 ± 11.99 ng/mL) compared to those with limited sun exposure (28.97 ± 9.28 ng/mL). Moreover, the time spent outdoors, seasonal changes, and the duration of sun exposure affected the levels of vitamin D. These findings depict the vitamin D status of the elderly population of Drâa-Tafilalet, recognized as one of Morocco's poorest regions, shedding light on the significant influencers. Nonetheless, additional research is necessary to explore the correlation between dietary habits, sunlight exposure, and vitamin D levels in both young and elderly populations.

Role of Calcitriol and Vitamin D Receptor (VDR) Gene Polymorphisms in Alzheimer's Disease

Alzheimer's disease (AD) is characterized by amyloid beta (Aβ) buildup and neuronal degeneration. An association between low serum vitamin D levels and an increased risk of AD has been reported in several epidemiological studies. Calcitriol (1,25-dihydroxycholecalciferol) is the active form of vitamin D, and is generated in the kidney and many other tissues/organs, including the brain. It is a steroid hormone that regulates important functions like calcium/phosphorous levels, bone mineralization, and immunomodulation, indicating its broader systemic significance. In addition, calcitriol confers neuroprotection by mitigating oxidative stress and neuroinflammation, promoting the clearance of Aβ, myelin formation, neurogenesis, neurotransmission, and autophagy. The receptors to which calcitriol binds (vitamin D receptors; VDRs) to exert its effects are distributed over many organs and tissues, representing other significant roles of calcitriol beyond sustaining bone health. The biological effects of calcitriol are manifested through genomic (classical) and non-genomic actions through different pathways. The first is a slow genomic effect involving nuclear VDR directly affecting gene transcription. The association of AD with VDR gene polymorphisms relies on the changes in vitamin D consumption, which lowers VDR expression, protein stability, and binding affinity. It leads to the altered expression of genes involved in the neuroprotective effects of calcitriol. This review summarizes the neuroprotective mechanism of calcitriol and the role of VDR polymorphisms in AD, and might help develop potential therapeutic strategies and markers for AD in the future.

A randomized controlled trial of Vitamin D supplementation in Iranian patients with schizophrenia: Effects on serum levels of glycogen synthase kinase-3β and symptom severity

BACKGROUND

Growing evidence has shown that hypovitaminosis D is a risk factor for developing schizophrenia and comorbid conditions. Therefore, this study aimed to examine the effect of vitamin D supplementation on serum levels of vitamin D, metabolic factors related to insulin resistance (IR) and the severity of the disorder in patients with schizophrenia.

METHODS

Forty-eight chronic male patients with schizophrenia with vitamin D deficiency (≤20 ng/mL= (≤50 nmol/l) were selected and randomly assigned to vitamin D treatment and placebo groups. Subjects were supplemented for 8 weeks with vitamin D (2000 IU/day) or placebo.

RESULTS

Within-group comparison revealed that the vitamin D group had a significant reduction in waist circumference, Positive and Negative Syndrome Scale - total score (PANSS-TS), and glycogen synthase kinase 3 beta (GSK-3β) levels (P = .022, P = <.001 and P = .013, respectively). On the other hand, the placebo group showed a significant increase in the level of fasting serum insulin and Homeostatic Model Assessment of Insulin Resistance (HOMA-IR) (P = .003 and P = .003). The between-group comparison showed a significant difference in terms of PANSS-TS, GSK-3β, fasting serum insulin (FSI), and HOMA-IR (P = .022, P = .048, P = .013 and P = .014 respectively).

CONCLUSIONS

Among vitamin D deficient patients with schizophrenia, vitamin D supplementation may affect GSK-3 β, an important biomarker in schizophrenia and insulin resistance. In addition, vitamin D supplementation in such patients may reduce the disorder's symptom severity.

The Impact of Vitamin D on Neuropsychiatric Disorders

Vitamin D is a fat-soluble vitamin that has multiple biological effects on the body. Recent findings have also linked vitamin D deficiency to a range of neuropsychiatric disorders. The aim of this review article is to provide insight into the metabolism of vitamin D and its effect on the body, especially on the brain, and to recognize the role of vitamin D in some neuropsychiatric disorders. Vitamin D is well-known as a neuroactive steroid that modulates brain functions and development. There is strong evidence to show that optimal vitamin D levels are important to protect against neuropsychiatric disorders. Vitamin D has also been proposed to alter neurotransmitter pathways in the central nervous system. Abnormalities in these neurotransmitters have been implicated in various neuropsychiatric diseases, such as schizophrenia, Parkinson's disease, and depression. Vitamin D also has some reported neurosteroid-like actions, including regulation of calcium homeostasis, clearance of amyloid-peptide, and antioxidant and anti-inflammatory effects, as well as possible protection against the neurodegenerative mechanisms associated with Alzheimer's disease and autism. Vitamin D is an important modulator of brain development and has many functions in the brain. Several studies found that vitamin D has a protective role in neuropsychiatric disorders, and its supplementation decreases the development of these disorders and lowers their symptoms. Therefore, evidence shows that early intervention to maintain vitamin D concentrations at sufficiently high levels is crucial to slow, prevent, or improve neurocognitive decline.

The effects of low-fat dairy products fortified with 1500 IU vitamin D3 on serum liver function biomarkers in adults with abdominal obesity: a randomized controlled trial

INTRODUCTION

Vitamin D deficiency has been reported to affect liver function biomarkers. This study was aimed to investigate the effect of consuming vitamin D fortified low-fat dairy products on liver function tests in adults with abdominal obesity.

METHODS

This total blinded randomized controlled trial was undertaken on otherwise healthy abdominally obese adults living in Mashhad, Iran. Milk and yogurt were fortified with 1500 IU vitamin D3 nano-capsules. Participants were randomized to receive fortified milk (n = 73), plain milk (n = 73), fortified yogurt (n = 69), and plain yogurt (n = 74) for 10 weeks. Blood samples were taken at baseline and at the end of the study to assess serum levels of vitamin D, alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase (ALP), and Gamma glutamyl transferase.

RESULTS

A total of 289 participants completed the study (54% female). The groups were homogenous in terms of age, sex, weight, energy intake, and physical activity level (p-value > 0.05). After the trial, vitamin D serum levels were significantly increased in both groups receiving fortified products (both p < 0.001). There was a significant time*group effect only in serum ALP (p < 0.001).

CONCLUSION

Consumption of dairy products fortified by 1500 IU vitamin D3 might have detrimental effects on serum levels of some liver enzymes in individuals with abdominal obesity. Further studies needed to determine these effects and underlying mechanisms.

TRIAL REGISTRATION

IRCT20101130005280N27 .

The Influence of Vitamin D Status on Cognitive Ability in Patients with Bipolar Disorder and Healthy Controls

Recent evidence on the association between vitamin D and cognition in mentally healthy individuals is inconsistent. Furthermore, the link between vitamin D and cognitive ability in individuals with bipolar disorder has not been studied yet. Thus, we aimed to investigate the association between 25-hydroxyvitamin D (25(OH)D), 24,25 dihydroxyvitamin D (24,25(OH)2D, the vitamin D metabolite ratio (VMR) and cognition in a cohort of euthymic patients with bipolar disorder. Vitamin D metabolites were measured simultaneously by liquid-chromatography tandem mass-spectrometry in serum samples from 86 outpatients with bipolar disorder and 93 healthy controls. Neither the inactive precursor 25(OH)D, nor the primary vitamin D catabolite 24,25(OH)2D, or the vitamin D metabolite ratio were significantly associated with the domains "attention", "memory", or "executive function" in individuals with bipolar disorder and healthy controls. Further, no vitamin D deficiency effect or interaction group × vitamin D deficiency was found in the cognitive domain scores. In summary, the present study does not support vitamin D metabolism as a modulating factor of cognitive function in euthymic BD patients. Considering the current study's cross-sectional design, future research should expand these results in a longitudinal setting and include additional aspects of mental health, such as manic or depressive symptoms, long-term illness course and psychopharmacological treatment.

Vitamin D deficiency and genetic polymorphisms of vitamin D-associated genes in Parkinson's disease

Parkinson's disease (PD) and vitamin D share a unique link as vitamin D deficiency (VDD) prevails in PD. Thus, an in-depth understanding of vitamin D biology in PD might be crucial for therapeutic strategies emphasising vitamin D. Specifically, explicating the effect of VDD and genetic polymorphisms of vitamin D-associated genes in PD, like VDR (vitamin D receptor) or GC (vitamin D binding protein) may aid the process along with polymorphisms of vitamin D metabolising genes (e.g., CYP2R1 and CYP27A1) in PD. Literature review of single nucleotide polymorphisms (SNPs) related to vitamin D levels [GC (GC1-rs7041 and GC2-rs4588), CYP2R1, CYP24A1 and CYP27B1] and vitamin D function [VDR (FokI - rs2228570 and rs10735810; ApaI - rs7976091, rs7975232BsmI and rs1544410; and TaqI - rs731236)] was conducted to explore their relationship with PD severity globally. VDR-FokI polymorphism was reported to be significantly associated with PD in Hungarian, Chinese and Japanese populations, whereas VDR-ApaI polymorphism was found to affect PD in the Iranian population. However, VDR-TaqI and BsmI polymorphisms had no significant association with PD severity. Conversely, GC1 polymorphisms reportedly affected vitamin D levels without influencing the disease severity. CYP2R1 (excluding rs1993116) was also reportedly linked to clinical manifestations of PD. Genetic polymorphisms might cause VDD despite enough sunlight exposure and vitamin D-rich food intake, enhancing inflammation, there by influencing PD pathophysiology. Knowledge of the polymorphisms associated with VDD appears promising for developing precision vitamin D-dosing therapeutic strategies against PD.

Genome-wide association studies: utility and limitations for research in physiology

Physiological systems are subject to interindividual variation encoded by genetics. Genome-wide association studies (GWAS) operate by surveying thousands of genetic variants from a substantial number of individuals and assessing their association to a trait of interest, be it a physiological variable, a molecular phenotype (e.g. gene expression), or even a disease or condition. Through a myriad of methods, GWAS downstream analyses then explore the functional consequences of each variant and attempt to ascertain a causal relationship to the phenotype of interest, as well as to delve into its links to other traits. This type of investigation allows mechanistic insights into physiological functions, pathological disturbances and shared biological processes between traits (i.e. pleiotropy). An exciting example is the discovery of a new thyroid hormone transporter (SLC17A4) and hormone metabolising enzyme (AADAT) from a GWAS on free thyroxine levels. Therefore, GWAS have substantially contributed with insights into physiology and have been shown to be useful in unveiling the genetic control underlying complex traits and pathological conditions; they will continue to do so with global collaborations and advances in genotyping technology. Finally, the increasing number of trans-ancestry GWAS and initiatives to include ancestry diversity in genomics will boost the power for discoveries, making them also applicable to non-European populations.

Evaluating the Feasibility of Pro-Neurotensin and 25-Hydroxyvitamin D3 as Possible Indicators for Type 2 Diabetes Mellitus and Its Complications

(1) Background: Type 2 diabetes mellitus (T2DM) and metabolic syndrome are associated with decreased vitamin D. In contrast, high pro-neurotensin (pro-NT) levels are linked with an increased risk of T2DM and cardiovascular disease. We aimed to determine the validity of pro-NT and 25-dihydroxy vitamin D3 levels as predictors for T2DM complications; (2) Methods: One hundred T2DM, and one hundred healthy volunteers participated in this case-control study. Their Pro-NT and 25-hydroxyvitamin D3 levels were evaluated using the ELISA technique; (3) Results: Pro-NT and 25 (OH) vitamin D3 have significant validity and accuracy in T2DM prediction, 84.5%, and 90.5%, respectively (p = 0.001). At a value of <29.5, 25-Hydroxy vitamin D3 showed 88% sensitivity and 93% specificity in predicting T2DM. At a value of >124 Pmol/L, Pro-NT showed 81% sensitivity and 88% specificity in predicting T2DM. At a value of 16.5, 25-Hydroxy vitamin D3 had 78.4% sensitivity and 68.3% specificity in predicting T2DM complications. At a value of >158 pmol/L, Pro-NT predicted T2DM complications with 67.6% sensitivity and 56.0% specificity; (4) Conclusions: 25 (OH) Vit D3 and Pro-NT could identify T2DM patients and predict T2DM complications. More extensive research is required to adequately validate this novel perspective with a large population study.

Design, Synthesis, Biological Activity, and Structural Analysis of Novel Des-C-Ring and Aromatic-D-Ring Analogues of 1α,25-Dihydroxyvitamin D3

The toxic calcemic effects of the natural hormone 1α,25-dihydroxyvitamin D₃ (1,25D₃, 1,25-dihydroxycholecalciferol) in the treatment of hyperproliferative diseases demand the development of highly active and noncalcemic vitamin D analogues. We report the development of two highly active and noncalcemic analogues of 1,25D₃ that lack the C-ring and possess an m-phenylene ring that replaces the natural D-ring. The new analogues (3a, 3b) are characterized by an additional six-carbon hydroxylated side chain attached either to the aromatic nucleus or to the triene system. Both compounds were synthesized by the Pd-catalyzed tandem cyclization/cross coupling approach starting from alkyne 6 and diphenol 8. Key steps include a stereoselective Cu-assisted addition of a Grignard reagent to an aromatic alkyne and a Takai olefination of an aromatic aldehyde. The new compounds are noncalcemic and show transcriptional and antiproliferative activities similar to 1,25D₃. Structural analysis revealed that they induce a large conformational rearrangement of the vitamin D receptor around helix 6.

Role of Multiple Vitamin D-Related Polymorphisms in Multiple Sclerosis Severity: Preliminary Findings

BACKGROUND

Multiple Sclerosis (MS) is a multifactorial disease whose pathogenesis is the result of interaction among genetic, epigenetic, and environmental factors. Among these, a role for vitamin D hypovitaminosis has emerged in recent decades. Vitamin D levels are influenced by both environmental and genetic factors. Single nucleotide polymorphisms (SNPs) in genes codifying for molecules involved in vitamin D metabolism have been associated with an increased risk of developing MS. However, few studies assessed the association of such SNPs with the severity of the disease. The aim of this observational study was to evaluate the potential association among vitamin D status, MS severity, and vitamin D-related SNPs, alone or in combination.

METHODS

In a cohort of 100 MS patients, we genotyped 18 SNPs in the following genes: NAD synthetase 1, CYP2R1, vitamin D binding protein, vitamin D receptor, Retinoid X Receptor-α, KLOTHO, CYP24A1, and CYP27A1. Serum 25(OH)D3 levels were measured by high-performance liquid chromatography. Genotyping was performed by real-time polymerase chain reaction or PCR-RFLP.

RESULTS

We did not find any association between SNPs, alone or in combination, and MS severity.

CONCLUSION

In this study, we make an initial evaluation of the possible influence of several SNPs in vitamin D-related genes on MS severity.

Effects of vitamin D receptor gene polymorphisms on the prognosis of COVID-19

PURPOSE

Vitamin D deficiency has emerged as another potential risk factor for coronavirus disease (COVID-19) due to the immunomodulatory effects of 25 hydroxyvitamin D [25 (OH)D]. Vitamin D receptor (VDR) gene polymorphisms such as Fok I, Bsm I, Apa I, and Taq I are also associated with different courses of viral infections. This study aimed to evaluate the association between the VDR gene polymorphism at Fok I, Taq I, Bsm I, and Apa I genotypes and the prognosis of COVID-19 in respect to vitamin D deficiency.

METHODS

Two-hundred ninety-seven patients with COVID-19 were enrolled. Serum 25 (OH)D levels were measured. Four variant regions of the VDR gene, FokI, BsmI, ApaI, and TaqI were determined.

RESULTS

Eighty-three percent of subjects had vitamin D deficiency, and 40.7% of the whole group had severe deficiency. Median 25 (OH)D level was 11.97 ng/ml. Vitamin D levels were not related to inflammatory markers, disease severity, admission to intensive care unit (ICU), and mortality. While disease severity was related to Fok I Ff genotype, it was Taq TT genotype for ICU admission. Moreover, the ApaI aa genotype was common among the patients who were died. None of the deceased subjects had the Fok I FF genotype.

CONCLUSION

25 (OH)D levels were not related to the severity and mortality of COVID-19. VDR gene polymorphisms are independently associated with the severity of COVID-19 and the survival of patients.

Crosstalk Between Gut Microflora and Vitamin D Receptor SNPs Are Associated with the Risk of Amnestic Mild Cognitive Impairment in a Chinese Elderly Population

Background: The interactions between environmental factors and genetic variants have been implicated in the pathogenesis of Alzheimer’s disease (AD). The altered gut microbiota (GM) and vitamin D deficiency are closely associated with the higher risk of AD. Objective: This study was performed to evaluate whether the crosstalk between GM and single nucleotide polymorphisms (SNPs) of vitamin D receptor (VDR) or vitamin D binding protein (VDBP) have a link with the risk of amnestic mild cognitive impairment (aMCI) in the Chinese elderly population. Methods: A total of 171 aMCI patients and 261 cognitive normal controls (NC) were enrolled in this study. Six tag SNPs of VDR and VDBP were genotyped by PCR-RFLP. The serum levels of vitamin D, Aβ1-42, and p-tau (181P) were determined by using of ELISA kits. The alterations in the GM were analyzed by full-length 16S ribosomal RNA (rRNA) gene sequencing. Results: The frequencies of AG genotype and A allele of VDR rs1544410 in aMCI group were significantly higher than that in NC group (genotype: p = 0.002, allele: p = 0.003). Patients with aMCI showed an abnormal GM composition compared with NC group. Interestingly, significant differences in GM composition were found between aMCI and NC group among individuals with AG genotype, as well as between individuals with AG and GG genotype of VDR rs1544410 among patients with aMCI. Conclusion: These results implicated that the crosstalk between gut microflora and vitamin D receptor variants are associated with the risk of aMCI in Chinese elderly population.

Vitamin D Status Assessment: Lack of Correlation between Serum and Hair 25-Hydroxycholecalciferol Levels in Healthy Young Adults

Vitamin D deficiency has been linked to numerous health problems, including those resulting from disturbed calcium-phosphorus homeostasis, and neuropsychiatric and autoimmune disorders. Nearly one-third of the global population has suboptimal levels of vitamin D, according to epidemiological data. Vitamin D status is usually determined by measuring serum 25(OH)D, but, for decades, serum 25(OH)D measurement has been hampered by a lack of standardization. There have been many recent initiatives to develop reference substances and methods for measuring vitamin D and its metabolites, and re-evaluating the optimal values. It was also suggested that alternative biological samples could also be used, such as hair, since it has been established that lipophilic substances, such as corticosteroids, can also be found in hair. The purpose of this study was to determine the correlation between 25(OH)D3 concentrations in serum and hair, and other demographic features in 26 healthy Caucasian young adult volunteers. The determination of 25(OH)D3 and cholecalciferol was carried out using liquid chromatography coupled with mass spectrometry (LC-MS) from blood and hair samples taken at two timepoints separated by nine weeks. In the hair samples of 18 out of 26 subjects, 25(OH)D was detected at a mean (±SEM) concentration of 17.07 ± 5.375 pg/mg at the first sampling time, and 58.90 ± 25.97 pg/mg at the second sampling time. A multiple linear regression analysis revealed no effects of gender, body mass index, supplementation, or sun exposure on hair 25(OH)D3 concentrations, but supplementation and sun exposure significantly increased serum 25(OH)D3 concentrations. In addition, serum and hair 25(OH)D3 concentrations did not correlate; however, there was a strong correlation between the two sampling times for serum 25(OH)D3 concentrations. In conclusion, this study confirmed that 25(OH)D3 could be detected in human hair, but its use as a biomarker warrants further investigations since no link was found between serum 25(OH)D3 concentrations, supplementation, sun exposure, and hair 25(OH)D3 concentrations levels.

Vitamin D and Parkinson's Disease

Vitamin D is a fat-soluble secosteroid, traditionally considered a key regulator of bone metabolism, calcium and phosphorous homeostasis. Its action is made possible through the binding to the vitamin D receptor (VDR), after which it directly and indirectly modulates the expression of thousands of genes. Vitamin D is important for brain development, mature brain activity and associated with many neurological diseases, including Parkinson’s disease (PD). High frequency of vitamin D deficiency in patients with Parkinson’s disease compared to control population was noted nearly twenty years ago. This finding is of interest given vitamin D’s neuroprotective effect, exerted by the action of neurotrophic factors, regulation of nerve growth or through protection against cytotoxicity. Vitamin D deficiency seems to be related to disease severity and disease progression, evaluated by Unified Parkinson’s Disease Rating Scale (UPDRS) and Hoehn and Yahr (H&Y) scale, but not with age of PD onset and duration of disease. Additionally, fall risk has been associated with lower vitamin D levels in PD. However, while the association between vitamin D and motor-symptoms seems to be possible, results of studies investigating the association with non-motor symptoms are conflicting. In addition, very little evidence exists regarding the possibility to use vitamin D supplementation to reduce clinical manifestations and disability in patients with PD. However, considering the positive balance between potential benefits against its limited risks, vitamin D supplementation for PD patients will probably be considered in the near future, if further confirmed in clinical studies.

Characterization of Vitamin D Status in Older Persons with Cognitive Impairment

Vitamin D exerts a role in the maintenance of cognitive abilities and in frailty. Although several studies evaluated the interactions between vitamin D and cognitive impairment, results were conflicting. In a cohort of community-dwelling older persons, we described the association between vitamin D levels and cognitive decline and all-cause dementia evaluating frailty’s contribution. Our cohort included 509 adults, aged 64–92 years: 176 patients with mild cognitive impairment (MCI), 59 with Alzheimer’s Disease (AD), 26 with idiopathic Normal Pressure Hydrocephalus (iNPH), 133 with mixed dementia (MD) and 115 without cognitive decline. Frailty was measured by frailty index, and serum 25-hydroxyvitamin D concentrations through electrochemiluminescence immunoassays. We found a significant association between vitamin D levels and Mini Mental State Examination independently of cognitive impairment, age, sex and frailty. The patients with dementia (AD and MD) showed the lowest vitamin D levels, while MCI patients showed higher levels than the other groups. The most severe deficiency was observed in MD patients, the most aged as well as cognitively and functionally impaired. In conclusion, in our community-dwelling older persons investigated for a suspected cognitive impairment, we observed an association between vitamin D levels and cognitive decline, regardless of the frailty status.

Assessing the Effects of Vitamin D on Neural Network Function in Patients With Parkinson's Disease by Measuring the Fraction Amplitude of Low-Frequency Fluctuation

Background: Recently, many studies have shown that low vitamin D (VD) levels may be related to an increased risk of Parkinson's disease (PD), but the underlying mechanisms remain unclear. Objective: To explore the relationship between PD and VD levels, as well as to analyze the effects of VD on spontaneous brain activity and explore the possible mechanism of its involvement in PD risk. Methods: In a cross-sectional study, we quantified the difference in VD levels between 330 PD patients and 209 healthy controls (HC) to explore the correlation between VD and PD risk. We also acquired resting-state Functional Magnetic Resonance Imaging (rs-fMRI) data from 46 PD patients and 21 HC. The PD patients were divided into three groups according to 25(OH)D levels: PD patients with VD deficiency (PD + VDD), PD patients with VD insufficiency (PD + VDI), and PD patients with normal VD (PD + NVD). The effect of VD status on spontaneous neuronal activity in the whole brain was analyzed by measuring the fraction amplitude of low-frequency fluctuation (fALFF). Results: Compared with HC, the PD patients had lower serum 25(OH)D levels (23.60 ± 7.27 vs. 25.60 ± 5.78, P < 0.001). The 25(OH)D level may have a potential dose-dependent effect on the risk of PD (P _trend = 0.007). A high risk of PD was associated with VD deficiency [25(OH)D < 20 ng/mL, OR = 2.319], and the lowest quartile of 25(OH)D concentration was associated with a high risk of PD (OR = 1.941). In the rs-fMRI study, PD + VDD patients had wider brain regions with altered fALFF than other PD groups when compared with the corresponding HC groups. Both PD + VDD and PD + VDI showed higher fALFF in the cuneus, left precuneus, calcarine cortex and right lingual, as well as lower fALFF in the left middle temporal gyrus. PD + VDD patients also showed higher fALFF in the left superior, middle and inferior frontal gyri, as well as the left precentral gyrus than HC. Among PD patients, there was only a statistically significant difference in fALFF between the PD + VDD and PD + NVD groups. Compared with the PD + NVD group, PD + VDD patients exhibited higher fALFF in the left precentral and left postcentral gyrus, as well as the left inferior parietal lobule. Conclusion: These results demonstrate that PD patients had lower serum VD levels than HC, and VD may have a potential dose-dependent effect on PD risk. Lower serum VD levels can affect the spontaneous neuronal activity of default-mode network (DMN) and visual pathway neurons in PD patients, providing a possible mechanism for its effect on PD risk.

Serum Vitamin D as a Biomarker in Autoimmune, Psychiatric and Neurodegenerative Diseases

Vitamin D is a steroid hormone regulating calcium-phosphorus homeostasis, immune response and brain function. In the past thirty years, an increasing number of cohort studies, meta-analyses and randomized controlled trials (RTCs) evaluated the serum levels of 25-hydroxyvitamin D [25(OH)D], which is considered the Vitamin D status biomarker, in patients affected by neurological, psychiatric and autoimmune diseases. Although an association between low 25(OH)D serum levels and the prevalence of these diseases has been found, it is still unclear whether the serum 25(OH)D measurement can be clinically useful as a biomarker for diagnosis, prognosis and predicting treatment response in neurodegeneration, mental illness and immune-mediated disorders. The lack of standardized data, as well as discrepancies among the studies (in the analytical methods, cut-offs, endpoints and study sets), weakened the findings achieved, hindered pooling data, and, consequently, hampered drawing conclusions. This narrative review summarizes the main findings from the studies performed on serum 25(OH)D in neurological, psychiatric and autoimmune diseases, and clarifies whether or not serum 25(OH)D can be used as a reliable biomarker in these diseases.

Mendelian randomization study updates the effect of 25-hydroxyvitamin D levels on the risk of multiple sclerosis

Background

Observational studies and previous Mendelian randomization (MR) studies have shown that genetically low 25-hydroxyvitamin D (25OHD) levels are associated with a high susceptibility to multiple sclerosis (MS). The present MR study aims to update the causal estimates for the effects of 25OHD levels on MS risk.

Methods

To date, the largest genome-wide association study (GWAS) for serum 25OHD (n = 401,460) and MS (14,498 MS cases and 24,091 controls) was used to assess the effect of serum 25OHD levels on MS. All participants were of European ancestry. The MR-egger_intercept test and Cochran’s Q statistic were used to determine the pleiotropy and the heterogeneity, respectively. MR-egger, weighted median, inverse variance weighted (multiplicative random effects), simple mode, and weighted mode methods were used to evaluate the causal association of serum 25OHD levels with MS. Finally, the effect of a single 25OHD SNP (single nucleotide polymorphism) on MS was used to test the SNP bias.

Results

One hundred and fifteen newly identified serum 25OHD genetic variants were extracted from a large-scale serum 25OHD GWAS dataset. The 20 most effective and independent 25OHD genetic instrumental variables were extracted from the MS GWAS summary statistics. Pleiotropy analysis suggested no significant pleiotropic variant among the 20 selected 25OHD genetic instrument variants in MS GWAS datasets. As serum levels of 25OHD based on genetic changes increased, the risk of MS decreased using MR-egger (Beta = − 0.940, p = 0.001; OR = 0.391), weighted median (Beta = − 0.835, p = 0.000; OR = 0.434), IVW (Beta = − 0.781, p = 0.000; OR = 0.458), simple mode (Beta = − 1.484, p = 0.016; OR = 0.227), and weighted mode (Beta = − 0.913, p = 0.000; OR = 0.401). Our results were robust, with no obvious bias based on investigating the single 25OHD SNP on MS.

Conclusions

Our analysis suggested a causal association between genetically increased serum 25OHD levels and reduced MS in the European population.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-021-03205-6.

Effect of vitamin D on cognitive decline: results from two ancillary studies of the VITAL randomized trial

Low vitamin D levels have been associated with cognitive decline; however, few randomized trials have been conducted. In a trial, we evaluated vitamin D3 supplementation on cognitive decline. We included participants aged 60+ years (mean[SD] = 70.9[5.8] years) free of cardiovascular disease and cancer in two substudies in the VITAL 2 × 2 randomized trial of vitamin D3 (2000 IU/day of cholecalciferol) and fish oil supplements: 3424 had cognitive assessments by phone (eight neuropsychologic tests; 2.8 years follow-up) and 794 had in-person assessments (nine tests; 2.0 years follow-up). The primary, pre-specified outcome was decline over two assessments in global composite score (average z-scores of all tests); substudy-specific results were meta-analyzed. The pooled mean difference in annual rate of decline (MD) for vitamin D3 versus placebo was 0.01 (95% CI - 0.01, 0.02; p = 0.39). We observed no interaction with baseline 25-hydroxyvitamin-D levels (p-interaction = 0.84) and a significant interaction with self-reported race (p-interaction = 0.01). Among Black participants (19%), those assigned vitamin D3 versus placebo had better cognitive maintenance (MD = 0.04, 95% CI 0.01, 0.08, similar to that observed for Black participants 1.2 years apart in age). Thus, vitamin D3 (2000 IU/day cholecalciferol) supplementation was not associated with cognitive decline over 2-3 years among community-dwelling older participants but may provide modest cognitive benefits in older Black adults, although these results need confirmation.Trial registration ClinicalTrials.gov; VITAL (NCT01169259), VITAL-DEP (NCT01696435) and VITAL-Cog (NCT01669915); the date the registration for the parent trial (NCT01169259) was submitted to the registry: 7/26/2010 and the date of first patient enrollment in either of the ancillary studies for cognitive function in a subset of eligible VITAL participants: 9/14/2011.

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.

The clinical significance of vitamin D levels and vitamin D receptor mRNA expression in colorectal neoplasms

BACKGROUND/AIM

This study aimed to investigate the clinical significance of changes in vitamin D [25(OH)D] levels and vitamin D receptor (VDR) mRNA expression in colorectal adenoma development.

METHODS

Plasma concentrations of 25(OH)D and mRNA expression of VDR in tissues were determined by enzyme-linked immunosorbent assay (ELISA) and real-time fluorescence quantitative polymerase chain reaction (RT-qPCR), respectively. In addition, the concentration of plasma 25(OH)D and levels of VDR mRNA in tissues were compared among healthy individuals and adenoma and adenocarcinoma patients.

RESULTS

Vitamin D receptor expression in colorectal adenocarcinoma tissues was significantly lower than that in para-cancerous tissues that were >5 cm away from malignant tumor sites (p < 0.01). The level of VDR expression in normal colorectal tissues from healthy individuals was significantly higher than that in colorectal adenomas (p < 0.01) and colorectal adenocarcinomas (p < 0.01); however, the VDR expression was not significantly different between colorectal adenomas and colorectal adenocarcinomas (p = 0.106). The concentration of 25(OH)D in healthy individuals was significantly higher than that in patients with colorectal adenomas (p < 0.01) and colorectal adenocarcinomas (p < 0.01); however, the concentration of 25(OH)D was not significantly different between colorectal adenomas and colorectal adenocarcinomas (p = 0.489). A low concentration of 25(OH)D was considered a risk factor for colorectal adenoma and colorectal adenocarcinoma, with odds ratios of 4.875 and 2.925, respectively.

CONCLUSIONS

The 25(OH)D levels and VDR mRNA expression might be associated with the development of colorectal adenoma and its progression to adenocarcinoma.

Vitamin D level, lipid profile, and vitamin D receptor and transporter gene variants in sickle cell disease patients from Kurdistan of Iraq

INTRODUCTION

Sickle cell disease (SCD) patients are susceptible to the development of vitamin D deficiency (VDD). Vitamin D through binding to vitamin D receptor (VDR) exerts its function and affects gene transcription in target tissues. VDR gene variants affect bone mineral density.

METHODS

In a case-control study, 101 SCD patients including 61 sickle cell anemia (SCA), 39 S/β-thalassemia, and 1 HbS/HbD (SD) along with 110 healthy individuals from Kurdistan of Iraq were studied. The lipid profile, vitamin D level, FokI, and TaqI variants of VDR and group-specific component (GC) were detected using the standard enzymatic method, the immunodiagnostic systems limited EIA kit and PCR-RFLP methods, respectively.

RESULTS

Around 93% and 82% of SCA and S/β-thalassemia patients, respectively, had VDD compared to 83% of healthy individuals. Severe VDD (<10 ng/ml) was detected in 78.7% of patients with HbSS. Plasma levels of total cholesterol, HDL-C, and LDL-C in SCD patients were significantly lower compared to controls. Vitamin D levels were negatively correlated to TG and positively correlated to total cholesterol and HDL-C. The frequencies of the C allele of FokI were 81.7% (p = 0.003), 80.3% (p = 0.034), and 84.6% (p = 0.011) in all SCD, SCA, and S/β-thalassemia patients, respectively, compared to 69.1% in controls. However, no significant difference was detected comparing the frequencies of VDR TaqI and GC polymorphisms between SCD patients and controls.

CONCLUSION

In the present study, we found hypocholesterolemia, high prevalence of VDR FokI C allele, and low vitamin D levels among children and adults with SCD from Kurdistan of Iraq.

The Assessment of Serum Concentrations of AGEs and Their Soluble Receptor (sRAGE) in Multiple Sclerosis Patients

BACKGROUND

Advanced glycation end products (AGEs) are involved in the pathogenesis of many diseases, including neurodegenerative diseases such as multiple sclerosis (MS). The aim of the study was to determine serum concentrations of AGEs and their soluble receptor (sRAGE) in MS patients and healthy controls and to investigate their possible influence on disease activity.

METHODS

Serum concentrations of AGE and sRAGE in patients with MS and healthy controls were determined by enzyme-linked immunosorbent assay (ELISA).

RESULTS

The mean serum AGE concentration in patients with MS was higher than in healthy controls, whereas the mean serum sRAGE concentration was lower than in the control group. However, the differences were not statistically significant. In MS patients, serum AGE and sRAGE concentrations did not differ significantly, depending on the duration of the disease and the Expanded Disability Status Scale (EDSS) score.

CONCLUSIONS

Multiple sclerosis may be accompanied by disturbances of the AGE-sRAGE axis. However, further studies are warranted to confirm it. The duration of the disease and the degree of disability do not seem to affect the progression of the glycation process, particularly in the stable phase of the disease.

Biochemical Biomarkers and Neurodegenerative Diseases

Neurodegenerative diseases (ND) are a heterogeneous group of disorders characterized by progressive dysfunction and loss of neurons in different areas of the central nervous system or peripheral nervous system [...].

Effect of Vitamin D Supplements on Relapse Rate and Expanded Disability Status Scale (EDSS) in Multiple Sclerosis (MS): A Systematic Review and Meta-Analysis

Background

Multiple sclerosis (MS) is an inflammatory disease while there are controversies regarding the role of vitamin D supplements in controlling relapse and disability improvement during treatment.

Objective

The goal of this systematic review and meta-analysis was to evaluate the effect of vitamin D supplements on MS-related relapse and the Expanded Disability Status Scale (EDSS).

Methods

We searched databases to include randomized clinical trials (RCTs) which were published up to October 2018. We included RCTs, being single-blinded or double-blinded or open-label trials in which one of the main outcomes was EDSS and/or relapse after vitamin D supplementation. All statistical analyses were performed using RevMan 5.3. Odds ratios (OR) and 95% confidence intervals (CI) were calculated for relapse between treatment arms. The mean difference was calculated for EDSS comparisons.

Results

Nine articles were included for analysis. Of these nine studies, five compared vitamin D supplement groups with placebo (group 1 studies), and four compared high- and low-dose vitamin D groups. A total of 561 patients were analyzed. Being treated with vitamin D instead of placebo showed no effect on relapse rate (OR = 0.66, 95% CI = 0.28-1.54) as well as EDSS (mean difference = 0.06, 95%CI [-0.31, 0.42]). The results of studies comparing high- vs. low-dose vitamin D interventions showed no significant effect on relapse rate (OR = 1.08, 95%CI [0.29-4.08] as well as final EDSS (mean difference = 0.17, 95% CI = -0.73, 1.07).

Conclusions

Our findings show that vitamin D supplements (high or low dose) have no significant effect on relapse rate and disability during treatment in MS patients.

Association of vitamin D pathway genes polymorphisms with pulmonary tuberculosis susceptibility in a Chinese population

OBJECTIVE

This study aimed to evaluate the association of single nucleotide polymorphisms (SNPs) of vitamin D metabolic pathway genes with susceptibility to pulmonary tuberculosis (PTB).

METHODS

Nine hundred seventy-nine patients (490 PTB cases and 489 healthy controls) were included in this study. Seventeen SNPs of vitamin D metabolic pathway genes, including CYP24A1, CYP27A1, CYP27B1, CYP2R1, GC, and DHCR7, were genotyped with improved multiple ligase detection reaction (iMLDR).

RESULTS

The GC rs3733359 GA, rs16847024 CT genotypes were significantly associated with the reduced risk of PTB, and the rs3733359 A, rs16847024 T alleles were also associated with the decreased PTB susceptibility. The GT genotype of GC rs4588 variant was significantly higher in patients with PTB when compared to controls. Moreover, the increased risk of rs3733359 and rs16847024 variants, and a decreased risk of rs4588, were found under the dominant mode among the PTB patients. However, there was no significant relationship of CYP24A1, CYP27A1, CYP27B1, CYP2R1, and DHCR7 polymorphisms with the risk of PTB. In CYP27A1, the rs17470271 T and rs933994 T alleles were significantly associated with leukopenia, drug resistance in the PTB patients, respectively. In GC gene, the rs7041 and rs3733359 variants were found to be associated with pulmonary infection, fever in the PTB patients, respectively. The increased frequency of rs16847024 TT genotype was found in the PTB patients with fever and drug-induced liver damage. DHCR7 rs12785878 TT genotype, and T allele frequencies were both significantly associated with pulmonary infection in the PTB patients. The haplotype analysis showed that CYP24A1 TACT, CYP2R1 GGCT, GGAT, GC AATG haplotypes were related to PTB susceptibility.

CONCLUSION

Our study suggested that GC SNPs were associated with the genetic background of PTB. CYP27A1, GC, and DHCR7 genetic variations might contribute to several clinical phenotypes of PTB in Chinese.

Association of vitamin D metabolites with cognitive function and brain atrophy in elderly individuals - the Austrian stroke prevention study

BACKGROUND

Vitamin D is a well-established regulator of calcium and phosphate metabolism that has neurotrophic and neuroprotective properties. Deficiency of vitamin D has been proposed to promote cognitive dysfunction and brain atrophy. However, existing studies provide inconsistent results. Here we aimed to investigate the association between vitamin D metabolites, cognitive function and brain atrophy in a cohort of well-characterized community-dwelling elderly individuals with normal neurological status and without history of stroke and dementia.

METHODS

25(OH)D3, 25(OH)D2 and 24,25(OH)2D3 were measured by liquid-chromatography tandem mass-spectrometry in serum samples from 390 community-dwelling elderly individuals. All participants underwent thorough neuropsychiatric tests capturing memory, executive function and visuopractical skills. In 139 of these individuals, MRI of the brain was performed in order to capture neurodegenerative and vascular changes.

RESULTS

Total 25(OH)D (ß=0.003, 0.037), 24,25(OH)2D3 (ß=0.0456, p=0.010) and vitamin D metabolite ratio (VMR) (ß=0.0467, p=0.012) were significantly related to memory function. Adjustment for multiple testing weakened these relationships, but trends (p≤0.10) remained. 24,25(OH)2D3 and VMR showed similar trends also for visuopractical skills and global cognitive function. No significant relationships existed between vitamin D metabolites and MRI derived indices of neurodegeneration and vascular changes. Sub-group analyses of individuals with low concentrations of 25(OH)D and 24,25(OH)2D3 showed significantly worse memory function compared to individuals with normal or high concentrations.

CONCLUSIONS

Vitamin D deficient individuals appear to have a modest reduction of memory function without structural brain atrophy. Future studies should explore if vitamin D supplementation can improve cognitive function.

A Case of Double Standard: Sex Differences in Multiple Sclerosis Risk Factors

Multiple sclerosis is a complex, multifactorial, dysimmune disease prevalent in women. Its etiopathogenesis is extremely intricate, since each risk factor behaves as a variable that is interconnected with others. In order to understand these interactions, sex must be considered as a determining element, either in a protective or pathological sense, and not as one of many variables. In particular, sex seems to highly influence immune response at chromosomal, epigenetic, and hormonal levels. Environmental and genetic risk factors cannot be considered without sex, since sex-based immunological differences deeply affect disease onset, course, and prognosis. Understanding the mechanisms underlying sex-based differences is necessary in order to develop a more effective and personalized therapeutic approach.

FOXP3 and GATA3 Polymorphisms, Vitamin D3 and Multiple Sclerosis

BACKGROUND

Regulatory T cells (Tregs) alterations have been implicated in the pathogenesis of Multiple Sclerosis (MS). Recently, a crucial role of the X-Linked Forkhead Box P3 (FoxP3) for the development and the stability of Tregs has emerged, and FOXP3 gene polymorphisms have been associated with the susceptibility to autoimmune diseases. The expression of Foxp3 in Tregs is regulated by the transcription factor GATA binding-protein 3 (GATA3) and vitamin D3. The aim of this retrospective case-control study was to investigate the potential association between FOXP3 and GATA3 genetic variants, Vitamin D3, and MS risk.

METHODS

We analyzed two polymorphisms in the FOXP3 gene (rs3761547 and rs3761548) and a polymorphism in the GATA3 gene (rs3824662) in 106 MS patients and 113 healthy controls. Serum 25(OH)D3 was also measured in all participants.

RESULTS

No statistically significant genotypic and allelic differences were found in the distribution of FOXP3 rs3761547 and rs3761548, or GATA3 rs3824662 in the MS patients, compared with controls. Patients that were homozygous for rs3761547 had lower 25(OH)D3 levels.

CONCLUSIONS

Our findings did not show any association among FOXP3 and GATA3 SNPs, vitamin D3, and MS susceptibility.

Neurogranin as a Novel Biomarker in Alzheimer's Disease

BACKGROUND

In this study, we investigated the possible role of 2 novel biomarkers of synaptic damage, namely, neurogranin and α-synuclein, in Alzheimer disease (AD).

METHODS

The study was performed in a cohort consisting of patients with AD and those without AD, including individuals with other neurological diseases. Cerebrospinal fluid (CSF) neurogranin and α-synuclein levels were measured by sensitive enzyme-linked immunosorbent assays (ELISAs).

RESULTS

We found significantly increased levels of CSF neurogranin and α-synuclein in patients with AD than those without AD. Neurogranin was correlated with total tau (tTau) and phosphorylated tau (pTau), as well as with cognitive decline, in patients with AD. Receiver operating characteristic (ROC) curve analysis showed good diagnostic accuracy of neurogranin for AD at a cutoff point of 306 pg per mL with an area under the curve (AUC) of 0.872 and sensitivity and specificity of 84.2% and 78%, respectively.

CONCLUSIONS

Our findings support the use of CSF neurogranin as a biomarker of synapsis damage in patients with AD.

The Role of Vitamin D as a Biomarker in Alzheimer's Disease

Vitamin D and cognition is a popular association, which led to a remarkable body of literature data in the past 50 years. The brain can synthesize, catabolize, and receive Vitamin D, which has been proved to regulate many cellular processes in neurons and microglia. Vitamin D helps synaptic plasticity and neurotransmission in dopaminergic neural circuits and exerts anti-inflammatory and neuroprotective activities within the brain by reducing the synthesis of pro-inflammatory cytokines and the oxidative stress load. Further, Vitamin D action in the brain has been related to the clearance of amyloid plaques, which represent a feature of Alzheimer Disease (AD), by the immune cell. Based on these considerations, many studies have investigated the role of circulating Vitamin D levels in patients affected by a cognitive decline to assess Vitamin D's eventual role as a biomarker or a risk factor in AD. An association between low Vitamin D levels and the onset and progression of AD has been reported, and some interventional studies to evaluate the role of Vitamin D in preventing AD onset have been performed. However, many pitfalls affected the studies available, including substantial discrepancies in the methods used and the lack of standardized data. Despite many studies, it remains unclear whether Vitamin D can have a role in cognitive decline and AD. This narrative review aims to answer two key questions: whether Vitamin D can be used as a reliable tool for diagnosing, predicting prognosis and response to treatment in AD patients, and whether it is a modifiable risk factor for preventing AD onset.

Preclinical Therapy with Vitamin D3 in Experimental Encephalomyelitis: Efficacy and Comparison with Paricalcitol

Multiple sclerosis (MS) is a chronic demyelinating disease of the central nervous system (CNS). MS and its animal model called experimental autoimmune encephalomyelitis (EAE) immunopathogenesis involve a plethora of immune cells whose activation releases a variety of proinflammatory mediators and free radicals. Vitamin D3 (VitD) is endowed with immunomodulatory and antioxidant properties that we demonstrated to control EAE development. However, this protective effect triggered hypercalcemia. As such, we compared the therapeutic potential of VitD and paricalcitol (Pari), which is a non-hypercalcemic vitamin D analog, to control EAE. From the seventh day on after EAE induction, mice were injected with VitD or Pari every other day. VitD, but not Pari, displayed downmodulatory ability being able to reduce the recruitment of inflammatory cells, the mRNA expression of inflammatory parameters, and demyelination at the CNS. Lower production of proinflammatory cytokines by lymph node-derived cells and IL-17 by gut explants, and reduced intestinal inflammation were detected in the EAE/VitD group compared to the EAE untreated or Pari groups. Dendritic cells (DCs) differentiated in the presence of VitD developed a more tolerogenic phenotype than in the presence of Pari. These findings suggest that VitD, but not Pari, has the potential to be used as a preventive therapy to control MS severity.

Age-dependent VDR peak DNA methylation as a mechanism for latitude-dependent multiple sclerosis risk

BACKGROUND

The mechanisms linking UV radiation and vitamin D exposure to the risk of acquiring the latitude and critical period-dependent autoimmune disease, multiple sclerosis, is unclear. We examined the effect of vitamin D on DNA methylation and DNA methylation at vitamin D receptor binding sites in adult and paediatric myeloid cells. This was accomplished through differentiating CD34+ haematopoietic progenitors into CD14+ mononuclear phagocytes, in the presence and absence of calcitriol.

RESULTS

Few DNA methylation changes occurred in cells treated with calcitriol. However, several VDR-binding sites demonstrated increased DNA methylation in cells of adult origin when compared to cells of paediatric origin. This phenomenon was not observed at other transcription factor binding sites. Genes associated with these sites were enriched for intracellular signalling and cell activation pathways involved in myeloid cell differentiation and adaptive immune system regulation.

CONCLUSION

These results suggest vitamin D exposure at critical periods during development may contribute to latitude-related differences in autoimmune disease incidence.

Expression of CYP24A1 and other multiple sclerosis risk genes in peripheral blood indicates response to vitamin D in homeostatic and inflammatory conditions

Although genetic and epidemiological evidence indicates vitamin D insufficiency contributes to multiple sclerosis (MS), and serum levels of vitamin D increase on treatment with cholecalciferol, recent metanalyses indicate that this vitamin D form does not ameliorate disease. Genetic variation in genes regulating vitamin D, and regulated by vitamin D, affect MS risk. We evaluated if the expression of vitamin D responsive MS risk genes could be used to assess vitamin D response in immune cells. Peripheral blood mononuclear cells (PBMCs) were isolated from healthy controls and people with MS treated with dimethyl fumarate. We assayed changes in expression of vitamin D responsive MS risk (VDRMS) genes in response to treatment with 25 hydroxy vitamin D in the presence or absence of inflammatory stimuli. Expression of CYP24A1 and other VDRMS genes was significantly altered in PBMCs treated with vitamin D in the homeostatic and inflammatory models. Gene expression in MS samples had similar responses to controls, but lower initial expression of the risk genes. Vitamin D treatment abrogated these differences. Expression of CYP24A1 and other MS risk genes in blood immune cells indicate vitamin D response and could enable assessment of immunological response to vitamin D in clinical trials and on therapy.

Preliminary Results of the FASM Study, an On-Going Italian Active Pharmacovigilance Project

BACKGROUND AND AIM

Disease-modifying therapies (DMTs) used in multiple sclerosis (MS) have distinct safety profiles. In this paper, we report preliminary results of an on-going pharmacovigilance project (the FASM study).

RESULTS

Neurologists working at involved multiple sclerosis centers collected 272 Individual Case Safety Reports (ICSRs). Adverse drug reactions (ADRs) mainly occurred in adult patients and in a higher percentage of women compared to men. No difference was found in ADRs distribution by seriousness. The outcome was reported as favorable in 61% of ICSRs. Out of 272 ICSRs, almost 53% reported dimethyl fumarate, fingolimod and IFN beta 1a as suspected. These medications were commonly associated to the occurrence of ADRs related hematological, gastrointestinal, general, infective or cancer disorders. The median time to event (days) was 177 for dimethyl fumarate, 1058 for fingolimod and 413 for IFN beta 1a. The median time to event for the remaining suspected drugs was 226.

CONCLUSION

We believe that our results, together with those that will be presented at the end of the study, may bring new knowledge concerning the safety profile of DMTs and their proper use. This will provide the opportunity to draw new recommendations both for neurologists and patients.

Valproic acid therapy decreases serum 25-hydroxyvitamin D level in female infants and toddlers with epilepsy- a pilot longitudinal study

To evaluate if valproic acid (VPA) therapy is associated with vitamin D deficiency among infants and toddlers with epilepsy, a cross-sectional clinical study was conducted in 25 children with epilepsy taking VPA. Blood levels of calcium, phosphorus, alkaline phosphatase, and 25-hydroxy vitamin D [25(OH)D] and plasma VPA level were measured at 1- to 3-month intervals. At the initial and final measurements, vitamin D deficiency or insufficiency was recognized in 8 (32%) and 12 (42%), respectively. In girls, a decreasing trend in serum 25(OH)D levels (P<0.05) was observed. Polytherapy had a significant negative effect on the longitudinal change of 25(OH)D (P<0.05) in girls. In conclusion, our study indicates that a high proportion of girls after VPA therapy had hypovitaminosis D.

Some Common SNPs of the T-Cell Homeostasis-Related Genes Are Associated with Multiple Sclerosis, but Not with the Clinical Manifestations of the Disease, in the Polish Population

Purpose

Multiple sclerosis (MS) is an autoimmune disease, and genetic factors play an important role in its pathogenesis and progression. The aim of our study was to evaluate the frequencies of alleles and genetic variants of the T-cell homeostasis-related genes, in subjects with MS, as well as to investigate the association with MS clinical manifestations and disability.

Methods

94 subjects with MS and 160 healthy individuals have been genotyped for seven common single-nucleotide variants in IL-2RA, CTLA4, CD40, and PADI4 genes. The ages of onset, duration of the disease, and clinical condition of the MS subjects were analysed. We used the Chi² test confirmed with Fisher's exact test for statistical analysis.

Results

The frequency of allele T and CT/TT genotypes (rs7093069) in the IL2RA gene, as well as the T allele and CT/TT genotypes in rs12722598, were significantly higher in the control group. The significant differences between studied groups we also found for the G allele and GG/GA genotypes of rs3087243 in CTLA4 gene, which were more common among the control group. The heterozygous genotype TC (rs1883832) of CD40 gene was more common in the control subjects, and the frequency of the alleles and genotypes in the rs1748033 of the PADI4 gene did not differ between the studied groups. Between the studied genotypes, we did not observe any significant differences in the age of onset and duration of disease, including sex stratification.

Conclusion

Our results highlight the protective role of some of the T-cell homeostasis-related genetic variants in MS development, but not in its clinical manifestation.