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.

Associations of vitamin D receptor polymorphisms with risk of Alzheimer's disease, Parkinson's disease, and mild cognitive impairment: a systematic review and meta-analysis

Vitamin D is a lipid soluble steroid hormone, which plays a critical role in the calcium homeostasis, neuronal development, cellular differentiation, and growth by binding to vitamin D receptor (VDR). Associations between VDR gene polymorphism and Alzheimer's disease (AD), Parkinson's disease (PD), and mild cognitive impairment (MCI) risk has been investigated extensively, but the results remain ambiguous. The aim of this study was to comprehensively assess the correlations between four VDR polymorphisms (FokI, BsmI, TaqI, and ApaI) and susceptibility to AD, PD, and MCI. Crude odds ratios (ORs) and 95% confidence intervals (CIs) were calculated to determine the relationship of interest. Pooled analyses suggested that the ApaI polymorphism decreased the overall AD risk, and the TaqI increased the overall PD susceptibility. In addition, the BsmI and ApaI polymorphisms were significantly correlated with the overall MCI risk. Stratified analysis by ethnicity further showed that the TaqI and ApaI genotypes reduced the AD predisposition among Caucasians, while the TaqI polymorphism enhanced the PD risk among Asians. Intriguingly, carriers with the BB genotype significantly decreased the MCI risk in Asian descents, and the ApaI variant elevated the predisposition to MCI in Caucasians and Asians. Further studies are need to identify the role of VDR polymorphisms in AD, PD, and MCI susceptibility.

Transcriptome-based biomarker prediction for Parkinson's disease using genome-scale metabolic modeling

Parkinson's disease (PD) is the second most common neurodegenerative disease in the world. Identification of PD biomarkers is crucial for early diagnosis and to develop target-based therapeutic agents. Integrative analysis of genome-scale metabolic models (GEMs) and omics data provides a computational approach for the prediction of metabolite biomarkers. Here, we applied the TIMBR (Transcriptionally Inferred Metabolic Biomarker Response) algorithm and two modified versions of TIMBR to investigate potential metabolite biomarkers for PD. To this end, we mapped thirteen post-mortem PD transcriptome datasets from the substantia nigra region onto Human-GEM. We considered a metabolite as a candidate biomarker if its production was predicted to be more efficient by a TIMBR-family algorithm in control or PD case for the majority of the datasets. Different metrics based on well-known PD-related metabolite alterations, PD-associated pathways, and a list of 25 high-confidence PD metabolite biomarkers compiled from the literature were used to compare the prediction performance of the three algorithms tested. The modified algorithm with the highest prediction power based on the metrics was called TAMBOOR, TrAnscriptome-based Metabolite Biomarkers by On-Off Reactions, which was introduced for the first time in this study. TAMBOOR performed better in terms of capturing well-known pathway alterations and metabolite secretion changes in PD. Therefore, our tool has a strong potential to be used for the prediction of novel diagnostic biomarkers for human diseases.

Vitamin D Serum Levels and Vitamin D Receptor Genotype in Patients with Parkinson's Disease

BACKGROUND

Vitamin D is a steroid hormone, known to be involved in the pathogenesis of various neurodegenerative disorders, including Parkinson's disease (PD). We aimed to clarify the relationship between hypovitaminosis D and the predisposition for PD and its clinical presentation. An additional aim was to examine the specific gene polymorphisms associated with vitamin D level.

MATERIAL AND METHODS

Total level of 25(OH)-vitamin D (25(OH)D) was measured in the serum of parkinsonian patients (n = 113) and controls (n = 82) using a commercial immunoassay. Genetic analyses were performed using Taqman assays on Real Time PCR amplification system.

RESULTS

Higher frequency of vitamin D deficiency (<50 nmol/L) was observed in PD patients, compared to controls (40.7% and 23.2%, respectively, P = 0.010). It was also a positive predictive marker of PD (OR, 2.27; 95% CI, 1.206-4.298; P < 0.011). Significantly higher UPDRS (35.85 ± 1.35 and 32.09 ± 0.99, respectively, P = 0.023) and HY scores (2(1.5-2.5) and 1.5(1.0-2.0), respectively, P = 0.005) were present in patients with 25(OH)D level < 50 nmol/L compared to patients with 25(OH)D level ≥ 50 nmol/L. Despite some trends observed, differences in allelic and genotypic distribution between controls and patients, as well as between subgroups, did not reach the level of significance (P > 0.05).

CONCLUSIONS

Findings of this study confirm the hypothesis of a significant relationship between hypovitaminosis D and PD. We demonstrated higher prevalence of vitamin D deficiency in PD patients, as well as its predictive potential for the onset and progression of PD.

Gene Signals and SNPs Associated with Parkinson's Disease: A Nutrigenomics and Computational Prospective Insights

Parkinson's disease is the most prevalent chronic neurodegenerative disease. Neurological conditions for PD were influenced by a variety of epigenetic factors and SNPs in some of the coexisting genes that were expressed. This article focused on nutrigenomics of PD and the prospective highlighting of how these genes are regulated in terms of nutritive factors and the genetic basis of PD risk, onset, and progression. Multigenetic associations of the following genetic alterations in the genes of SNCA, LRRK2, UCHL1, PARK2,PINK1, DJ-1, and ATP13A2 have been reported with the familial and de novo genetic origins of PD. Over the past two decades, significant attempts have been made to understand the biological mechanisms that are potential causes for this disease, as well as to identify therapeutic substances for the prevention and management of PD. Nutrigenomics has sparked considerable interest due to its nutritional, safe, and therapeutic effects on a variety of chronic diseases. In this study, we summarise some of the nutritive supplements that have an impact on PD.

The Vitamin D Receptor as a Potential Target for the Treatment of Age-Related Neurodegenerative Diseases Such as Alzheimer's and Parkinson's Diseases: A Narrative Review

The vitamin D receptor (VDR) belongs to the nuclear receptor superfamily of transcription factors. The VDR is expressed in diverse brain regions and has been implicated in the neuroprotective, antiaging, prosurvival, and anti-inflammatory action of vitamin D. Accordingly, a relationship between vitamin D insufficiency and susceptibility to neurodegenerative diseases has been suggested. However, due to the multitargeted mechanisms of vitamin D and its often overlapping genomic and nongenomic effects, the role of the VDR in brain pathologies remains obscure. In this narrative review, we present progress in deciphering the molecular mechanism of nuclear VDR-mediated vitamin D effects on prosurvival and anti-inflammatory signaling pathway activity within the central nervous system. In line with the concept of the neurovascular unit in pathomechanisms of neurodegenerative diseases, a discussion of the role of the VDR in regulating the immune and vascular brain systems is also included. Next, we discuss the results of preclinical and clinical studies evaluating the significance of vitamin D status and the efficacy of vitamin D supplementation in the treatment of Parkinson's and Alzheimer's diseases, emphasizing the possible role of the VDR in these phenomena. Finally, the associations of some VDR polymorphisms with higher risks and severity of these neurodegenerative disorders are briefly summarized.

Vitamin D Metabolites: Analytical Challenges and Clinical Relevance

Recent research activities have provided new insights in vitamin D metabolism in various conditions. Furthermore, substantial progress has been made in the analysis of vitamin D metabolites and related biomarkers, such as vitamin D binding protein. Liquid chromatography tandem mass spectrometric (LC-MS/MS) methods are capable of accurately measuring multiple vitamin D metabolites in parallel. Nevertheless, only 25(OH)D and the biologically active form 1,25(OH)2D are routinely measured in clinical practice. While 25(OH)D remains the analyte of choice for the diagnosis of vitamin D deficiency, 1,25(OH)2D is only recommended in a few conditions with a dysregulated D metabolism. 24,25(OH)2D, free and bioavailable 25(OH)D, and the vitamin D metabolite ratio (VMR) have shown promising results, but technical pitfalls in their quantification, limited clinical data and the lack of reference values, impede their use in clinical practice. LC-MS/MS is the preferred method for the measurement of all vitamin D related analytes as it offers high sensitivity and specificity. In particular, 25(OH)D and 24,25(OH)2D can accurately be measured with this technology. When interpreted together, they seem to provide a functional measure of vitamin D metabolism beyond the analysis of 25(OH)D alone. The determination of VDBP, free and bioavailable 25(OH)D is compromised by unresolved analytical issues, lacking reference intervals and insufficient clinical data. Therefore, future research activities should focus on analytical standardization and exploration of their clinical value. This review provides an overview on established and new vitamin D related biomarkers including their pathophysiological role, preanalytical and analytical aspects, expected values, indications and influencing conditions.

Vitamin D (VD3) Intensifies the Effects of Exercise and Prevents Alterations of Behavior, Brain Oxidative Stress, and Neuroinflammation, in Hemiparkinsonian Rats

In the present study, we investigated the effects of physical exercise in the presence of Vitamin D3 (VD3), on 6-hydroxydopamine (6-OHDA)-lesioned hemiparkinsonian rats. The animals were divided into sham-operated (SO), 6-OHDA-lesioned, and 6-OHDA-lesioned plus VD3 (1 µg/kg, 21 days), in the absence (no exercise, NE) and presence (with exercise, WE) of physical exercise on a treadmill (30 min, speed of 20 cm/s, once a day/21 days). This procedure started, 24 h after the stereotaxic surgery (injections of 6-OHDA into the right striatum). The animals were then subjected to behavioral (rotarod, open field, and apomorphine tests) and their brain areas were dissected for neurochemical, dopamine (DA), 3,4-dihydroxyphenylacetic acid (DOPAC) determinations, and immunohistochemical studies for tyrosine hydroxylase (TH), dopamine transporter (DAT), and vitamin D receptor (VD3R). The effects on the brain oxidative stress: nitrite/nitrate, glutathione (GSH), and malondialdehyde (MDA) measurements were also evaluated. Behavioral changes of the 6-OHDA lesioned group were improved by exercise plus VD3. Similar results were observed in dopamine (DA) and 3,4-dihydroxyphenylacetic acid (DOPAC) concentrations increased by exercise and VD3, compared with SO groups. Additionally, tyrosine hydroxylase (TH) and dopamine transporter (DAT) immunoexpressions were decreased in the 6-OHDA-lesioned groups, with values normalized after exercise and VD3. The VD3 receptor immunoexpression decreased in the 6-OHDA (NE) group, and this was attenuated by exercise, especially after VD3. While 6-OHDA lesions increased, VD3 supplementation decreased the oxidative stress, which was intensified by exercise. VD3 showed neuroprotective properties that were intensified by physical exercise. These VD3 actions on hemiparkinsonian rats are possibly related to its antioxidant and anti-inflammatory effects.

Understanding the role of "sunshine vitamin D" in Parkinson's disease: A review

Next to Alzheimer's disease, Parkinson's disease constitutes the second most widespread neurological disorder, primarily affecting the older population. Its symptoms are noticeable with advancing age including tremors, postural imbalance, and slow movements, and over time, these symptoms get aggravated, progressing to osteoporosis, osteopenia, and risk of fractures. These symptoms correlate to low bone density and hence weakened bones; thus, vitamin D proves to be an intricate component of the pathogenesis of the disease. Moreover, lower serum concentrations of vitamin D have been found in diseased subjects. Supplementation with vitamin D can retard the aggravation of non-motor as well as motor symptoms of Parkinson's disease that include cognitive improvement along with the decline in risk of fractures. Also, vitamin D is extremely crucial for brain functioning, targeting dopaminergic neurons, and almost the entire functioning of the brain is affected. However, further exploration is required to determine the toxic dose of vitamin D in Parkinson's subjects. This "sunshine vitamin" surely can be a ray of sunshine for neurologically diseased subjects.

The effect of hypocalcemia on motor symptoms of Parkinson’s disease

Background

The disabling nature of Parkinson’s disease (PD) impairs functional mobility and worsens quality of life. Calcium imbalances are thought to have a significant role in the progression of PD.

Objective

To evaluate the relation between calcium deficiency and deterioration of PD motor symptoms.

Methods

A total of 28 idiopathic PD patients were subjected to motor symptoms evaluation using the modified Hoehn–Yahr scale (H–Y), Unified Parkinson’s Disease Rating Scale (UPDRS) Part II and III and Schwab and England Activities of Daily Living Scale (S–E ADL). Total and ionized serum calcium levels were measured for the PD patients and the 30 healthy control subjects.

Results

The level of ionized calcium was significantly lower among PD patients (4.19 mg/dl ± 0.53) than in control subjects (4.8 mg/dl ± 0.35) (p < 0.0001). The PD patients with hypocalcemia showed marked deterioration of motor symptoms and significant impairment of daily life activities when compared to PD patients with normal calcium levels regarding their scores on the modified H–Y scale (p = 0.001), UPDRS-III (p = 0.001), UPDRS-II (p = 0.001), and S–E ADL scale (p = 0.001). Ionized calcium correlated significantly with PD patients’ scores on the modified H–Y scale (p = 0.019), UPDRS-Part II (p = 0.001), UPDRS-Part III (p = 0.001) and S–E ADL scale (p = 0.001). The significant cutoff point of the ionized calcium for detection of the deteriorated PD patients that presented with stages more than grade 2 of the modified H–Y scale was < 3.99 (p = 0.037) with a sensitivity of 80% and specificity of 95%.

Conclusions

Our findings conclude that calcium deficiency could contribute to the deterioration of PD motor symptoms.

Therapeutic and mechanistic intervention of vitamin D in neuropsychiatric disorders

Vitamin D deficiency is believed to affect between 35 and 55% of the world's population, making it a hidden pandemic. In addition to its role in bone and calcium homeostasis, vitamin D has also been linked in preclinical and clinical research to brain function. These outcomes have also been used for a variety of neuropsychiatric and neurodevelopmental problems. Nevertheless, these individuals are more prone to develop signs of cognitive decline. This review will emphasize the association between vitamin D and neuropsychiatric illnesses such as autism, schizophrenia, depression, and Attention Deficit Hyperactivity Disorder (ADHD). While numerous research show vitamin D's essential role in cognitive function in neuropsychiatric illnesses, it is too early to propose its effect on cognitive symptoms with certainty. It is necessary to conduct additional research into the associations between vitamin D deficiency and cognitive abnormalities, particularly those found in autism, schizophrenia, depression, and ADHD, to develop initiatives that address the pressing need for novel and effective preventative therapeutic strategies.

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.

Targeting Nuclear Receptors in Neurodegeneration and Neuroinflammation

Nuclear receptors, also known as ligand-activated transcription factors, regulate gene expression upon ligand signals and present as attractive therapeutic targets especially in chronic diseases. Despite the therapeutic relevance of some nuclear receptors in various pathologies, their potential in neurodegeneration and neuroinflammation is insufficiently established. This perspective gathers preclinical and clinical data for a potential role of individual nuclear receptors as future targets in Alzheimer's disease, Parkinson's disease, and multiple sclerosis, and concomitantly evaluates the level of medicinal chemistry targeting these proteins. Considerable evidence suggests the high promise of ligand-activated transcription factors to counteract neurodegenerative diseases with a particularly high potential of several orphan nuclear receptors. However, potent tools are lacking for orphan receptors, and limited central nervous system exposure or insufficient selectivity also compromises the suitability of well-studied nuclear receptor ligands for functional studies. Medicinal chemistry efforts are needed to develop dedicated high-quality tool compounds for the therapeutic validation of nuclear receptors in neurodegenerative pathologies.

Vitamin D attenuated 6-OHDA-induced behavioural deficits, dopamine dysmetabolism, oxidative stress, and neuro-inflammation in mice

Background: L-DOPA, the predominant therapy for Parkinson's disease (PD) is associated with motor deficits after prolonged use. The nigrostriatal tract, a primary target of neurodegeneration in PD, contains abundant Vitamin-D receptors, suggesting a potential role for VD in the disease. Therefore, we tested the impact of Vitamin D3 (VD3) in a mouse model of PD.Methods: PD was induced in adult male C57BL6 mice by a single intrastriatal injection of 6-hydroxydopamine. Two weeks post lesion, these mice received injections of a vehicle, VD3, L-DOPA, or a combination of VD3/L-DOPA and compared with sham controls. Treatment lasted three weeks, during which motor-cognitive neurobehaviour was assessed. Five weeks post lesion, brains were collected and striatal levels of the following proteins assessed: tyrosine hydroxylase (TH), dopamine decarboxylase (DDC), monoamine oxidase (MAO-B), Catechol-O-methyl transferase (COMT), dopamine transporter (DAT), brain-derived neurotrophic factor (BDNF), microglia marker (CD11b), inflammation (IL-1β), apoptotic signaling (BAX) and oxidative stress (p47phox).Results: Treatment with VD3 attenuated behavioural deficits induced by 6-OHDA, protein associated with dopamine metabolism and biomarkers of oxidative stress. VD3 significantly increased contralateral wall touches, exploratory motor and cognitive activities. VD3 significantly enhanced the expression of TH, DAT, BDNF, while significantly reducing expression of MAO-B, CD11b, IL-I β and p47phox.Conclusion: VD3 reversed some of the 6-OHDA induced changes in proteins involved in modulating the dopamine system, behavioural deficits and oxidative stress biomarkers. The data suggests that VD3 might be beneficial in reducing L-DOPA dosage, thereby reducing problems associated with dosage and prolonged use of L-DOPA in PD management.

The relationships of vitamin D, vitamin D receptor gene polymorphisms, and vitamin D supplementation with Parkinson's disease

In recent years, many studies have investigated the correlations between Parkinson's disease (PD) and vitamin D status, but the conclusion remains elusive. The present review focuses on the associations between PD and serum vitamin D levels by reviewing studies on the associations of PD with serum vitamin D levels and vitamin D receptor (VDR) gene polymorphisms from PubMed, Web of Science, Cochrane Library, and Embase databases. We found that PD patients have lower vitamin D levels than healthy controls and that the vitamin D concentrations are negatively correlated with PD risk and severity. Furthermore, higher vitamin D concentrations are linked to better cognitive function and mood in PD patients. Findings on the relationship between VDR gene polymorphisms and the risk of PD are inconsistent, but the FokI (C/T) polymorphism is significantly linked with PD. The occurrence of FokI (C/T) gene polymorphism may influence the risk, severity, and cognitive ability of PD patients, while also possibly influencing the effect of Vitamin D3 supplementation in PD patients. In view of the neuroprotective effects of vitamin D and the close association between vitamin D and dopaminergic neurotransmission, interventional prospective studies on vitamin D supplementation in PD patients should be conducted in the future.

Nocturnal blood pressure changes in Parkinson's disease: correlation with autonomic dysfunction and vitamin D levels

Nocturnal blood pressure (BP) changes are an indicator of autonomic dysfunction. We aim to investigate the correlation between nocturnal blood pressure (BP) variability, vitamin D levels and Parkinson's disease severity (PD) in this study. Thirty-five patients with PD participated in the study. Disease severity was evaluated by United Parkinson's Disease Rating Scale (UPDRS) and Hoehn and Yahr Scale (HYS). Equivalent levodopa dose was calculated and 25-hydroxyvitamin D levels were measured. The Non-Motor Symptom Questionnaire (NMSQ) was applied to all patients. Ambulatory BP monitoring for 24 h was established. Patients were divided into three groups according to nocturnal BP results: dippers (normal finding-a decline in mean nighttime BP of more than 10%); non-dippers (pathological-a decline in mean nighttime BP of less than 10%); reverse dippers (pathological-an increase in mean nighttime BP) .The mean score of the NMSQ was higher in the group with HYS > 2 (p = 0.050). Four patients were dipper, 17 patients were non-dipper and 16 patients were reverse dipper. There was no significant difference between the three groups in terms of age, gender, disease duration, age of the disease onset, disease stage, disease duration, dopamine agonist usage, levodopa equivalent dose, vitamin D level and NMSQ scores. NMSQ scores are high in advanced PD. Ambulatory BP monitoring is useful in detecting autonomic dysfunction. The number of patients with non-dipping and reverse dipping is high in PD, independent from PD severity, drug dose, vitamin D and the other NMS symptoms.

Vitamin D status in idiopathic Parkinson’s disease: an Egyptian study

Background

Vitamin D is suggested to play an important role in neurodegenerative disorders.

Objective

To examine the association between serum 25 vitamin D3 and Parkinson’s disease (PD).

Materials and methods

Fifty patients suffering from PD and fifty age- and sex-matched healthy control subjects were included in the study. Patients were subjected to complete clinical assessment, and Unified Parkinson Disease Rating Scale (UPDRS) was done to evaluate severity of PD. Measurement of serum 25 vitamin D3 using enzyme-linked immuno sorbent assay (ELISA) was done for both patients and controls.

Results

Serum 25 vitamin D3 was significantly lower in PD patients compared to healthy controls. Twenty-five vitamin D3 serum level was significantly negatively correlated with age and age at onset of disease but not significantly correlated with disease duration and severity of Parkinson’s disease. Multiple regression analysis showed that serum 25 vitamin D3 was not found to be predictor for severity of PD.

Conclusion

There is an association between low vitamin D levels and PD. Therefore, vitamin D may have a role in the pathophysiology of PD.

The Influence of Vitamin D on Neurodegeneration and Neurological Disorders: A Rationale for its Physio-pathological Actions

Vitamin D is a steroid hormone implicated in the regulation of neuronal integrity and many brain functions. Its influence, as a nutrient and a hormone, on the physiopathology of the most common neurodegenerative diseases is continuously emphasized by new studies. This review addresses what is currently known about the action of vitamin D on the nervous system and neurodegenerative diseases such as Multiple Sclerosis, Alzheimer's disease, Parkinson's disease and Amyotrophic Lateral Sclerosis. Further vitamin D research is necessary to understand how the action of this "neuroactive" steroid can help to optimize the prevention and treatment of several neurological diseases.

Vitamin D deficiency in school-age Iranian children with attention-deficit/hyperactivity disorder (ADHD) symptoms: A critical comparison with healthy controls

The associations between serum vitamin D levels and the severity of attention-deficit/hyperactivity disorder (ADHD) symptoms were assessed among Iranian hospitalized children (50 ADHD cases and 50 healthy (non-ADHD) controls) during 2014-2015. Levels of ADHD severity and serum 25-hydroxyvitamin D (25OHD) were determined by the Conners' Parent Rating Scale (CPRS) test and an ELISA kit, respectively. The serum 25OHD concentrations of <10, 10-29, and >30 ng/mL were respectively considered as deficient (severe deficiency), insufficient (mild deficiency), and sufficient levels of vitamin D. The association of nutrient bioavailability with ADHD was evaluated by statistical and regression analyses.There was no significant difference in the mean of socio-demographic variables (e.g., gender, age, weight, BMI, daily intake of dairy products, and daily sunlight exposure) between ADHD and non-ADHD subjects. The mean serum 25OHD concentration (16.57 ± 9.09 ng/mL) was found to be significantly lower in ADHD children with more parathyroid hormone (PTH) levels as compared to controls (22.01 ± 12.67ng/mL). The sufficient 25OHD concentration was more predominant in the controls than the cases (p = 0.002). A severe deficiency of vitamin D was more found in children with ADHD (3.36 times). There was a negative and significant association between the participants' age and their serum 25OHD levels. Although 25OHD levels in boys were significantly more than those in girls, the reduction of serum 25OHD concentration among boys with ADHD was more severe compared to the patient girls(p = 0.014). The results support the importance of vitamins D role in ADHD patients through the regular monitoring of serum 25OHD levels.

Vitamin D and the nervous system

Objective: to summarise the activities that Vitamin D (VD) carries out in the brain and to clarify the potential role of VD in neurological diseases. Methods: a literature research has been performed in Pubmed using the following keywords: 'Vitamin D', 'nervous system', 'brain'. Results: the studies reviewed show that VD contributes to cerebral activity in both embryonic and adult brain, helping the connectivity of neural circuits responsible for locomotor, emotional and reward-dependent behavior. Low VD serum levels have been found in patients affected by Alzheimer Disease, Parkinson Disease, Multiple Sclerosis, Autism Spectrum Disorders, Sleep Disorders and Schizophrenia. Discussion: findings are controversial and should be interpreted with caution, since most of the studies performed have observational study set and few interventional studies are available, producing conflicting results. Overall, it can be stated that the potential role of Vitamin D in neurological diseases is mostly unclear and further randomised controlled trials are needed to understand better whether Vitamin D supplementation treatment can be useful in brain disorders.

Association Between Serum Vitamin D Levels and Parkinson's Disease: A Systematic Review and Meta-Analysis

Background: Vitamin D is an important secosteroid which is involved the development and regulation of brain activity. Several studies have focused on exploring the relationship between serum vitamin D levels and Parkinson's disease (PD), but the conclusion remains ambiguous.

Methods: We searched observational studies that explored the association between serum vitamin D levels and PD based on PubMed, EMBASE and Cochrane library from inception through to January 2018. The quality of included studies was evaluated by using Newcastle-Ottawa Scale (NOS). Statistical analysis of this meta-analysis was performed by Stata version 12.0 and R software.

Results: Twenty studies with a total of 2,866 PD patients and 2,734 controls were included. Compared with controls, PD patients had lower serum vitamin D levels (WMD −3.96, 95%CI −5.00, −2.92), especially in higher latitude regions (WMD −4.20, 95%CI −5.66, −2.75). Assay methods contributed significantly to high heterogeneity. Furthermore, PD patients with deficient vitamin D levels had advanced risk (OR 2.08, 95%CI 1.35, 3.19) than those patients with insufficient ones (OR = 1.73, 95%CI 1.48, 2.03). In addition, serum vitamin D levels were also related to the severity of PD (WMD −5.27, 95%CI −8.14, −2.39) and the summary correlation coefficient showed strongly negative correlation (r = −0.55, 95%CI −0.73, −0.29). Moreover, the pooled correlation coefficient revealed that serum vitamin D levels were also negatively correlated to the Unified Parkinson's Disease Rating Scale III (UPDRS III) (r = −0.36, 95%CI −0.53, −0.16), but did not correlate with the duration of PD (P = 0.37) and age of patients (P = 0.49).

Conclusion: Serum vitamin D levels are inversely associated with the risk and severity of PD. Our results provided an updated evidence of association between low vitamin D levels and PD and prompt the adjunctive therapeutic decisions about vitamin D replacement in PD.

Trace elements in ALS patients and their relationships with clinical severity

An exploratory study of trace elements in ALS and their relationships with clinical severity was detected. Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder that causes irreversible damage in humans, with the consequent loss of function of motoneurons (MNs), with a prognosis up to 5 years after diagnosis. Except to genetic rare cases it is not known the etiology of the disorder. Aim of our research is to investigate the possible role of heavy metals in the severity of the disease. In this study, by the use of plasma mass (ICP-MS), we have analyzed the content of essential and heavy metals such: Pb, Cd, Al, Hg, Mn, Fe, Cu, Zn, Se, Mg, and Ca, in blood, urine and hair of ALS patients and controls; moreover we divided the patients in two groups for disease severity and analyzed the difference among the groups, in order to study a possible involvement of metals in the severity of the damage. Our results suggest a protective role of Selenium, involved in protective antioxidant mechanisms, and a risk factor in the case of presence of Lead in blood. The levels of the other metals are not easy to interpret, because these may be due to life style and for essential metals a consequence of the disease condition, not a cause.

Vitamin D and vitamin D receptor levels in children with attention-deficit/hyperactivity disorder

OBJECTIVE

In this study, we aimed to evaluate vitamin D and vitamin D receptor levels in children with attention-deficit/hyperactivity disorder (ADHD).

PATIENTS AND METHODS

In this cross-sectional study, a total of 80 children including 40 ADHD patients (aged 6-12 years; 28 males and 12 females) and 40 age-, sex-, and season of blood collection-matched controls (aged 6-12 years; 25 males and 15 females) were enrolled. Serum vitamin D and vitamin D receptor levels and calcium, phosphorus, and alkaline phosphatase were measured. The vitamin D receptor levels in the serum were measured using the quantitative sandwich enzyme immunoassay technique.

RESULTS

Serum vitamin D and vitamin D receptor levels were found to be significantly lower in children with ADHD compared to healthy controls. No significant differences were found in serum calcium, phosphorus, and alkaline phosphatase levels. No significant differences were found among the ADHD subtypes in terms of serum vitamin D, vitamin D receptor, calcium, phosphorus and alkaline phosphatase levels.

CONCLUSION

This study suggests that children with ADHD have lower levels of vitamin D and vitamin D receptor. According to the authors' knowledge, this is the first study to describe vitamin D receptor levels in ADHD.

No clear support for a role for vitamin D in Parkinson's disease: A Mendelian randomization study

BACKGROUND

Observational studies have found that relative to healthy controls, patients with Parkinson's disease have lower circulating concentrations of 25-hydroxyvitamin D, a clinical biomarker of vitamin D status. However, the causality of this association is uncertain. We undertook a Mendelian randomization study to investigate whether genetically decreased 25-hydroxyvitamin D concentrations are associated with PD to minimize confounding and prevent bias because of reverse causation.

METHODS

As instrumental variables for the Mendelian randomization analysis, we used 4 single-nucleotide polymorphisms that affect 25-hydroxyvitamin D concentrations (rs2282679 in GC, rs12785878 near DHCR7, rs10741657 near CYP2R1, and rs6013897 near CYP24A1). Summary effect size estimates of the 4 single-nucleotide polymorphisms on PD were obtained from the International Parkinson's Disease Genomics Consortium (including 5333 PD cases and 12,019 controls). The estimates of the 4 single-nucleotide polymorphisms were combined using an inverse-variance weighted meta-analysis.

RESULTS

Of the 4 single-nucleotide polymorphisms associated with 25-hydroxyvitamin D concentrations, one (rs6013897 in CYP24A1) was associated with PD (odds ratio per 25-hydroxyvitamin D-decreasing allele, 1.09; 95% confidence interval, 1.02-1.16; P = 0.008), whereas no association was observed with the other 3 single-nucleotide polymorphisms (P > 0.23). The odds ratio of PD per genetically predicted 10% lower 25-hydroxyvitamin D concentration, based on the 4 single-nucleotide polymorphisms, was 0.98 (95% confidence interval, 0.93-1.04; P = 0.56).

CONCLUSIONS

This Mendelian randomization study provides no clear support that lowered 25-hydroxyvitamin D concentration is causally associated with risk of PD. © 2017 International Parkinson and Movement Disorder Society.

Low Serum Levels of 25-Hydroxyvitamin D Are Associated with Stroke Recurrence and Poor Functional Outcomes in Patients with Ischemic Stroke

OBJECTIVE

To evaluate the association between serum 25(OH) D levels and functional outcome and stroke recurrence events in a 6-month follow-up study in a cohort of patients with an acute ischemic stroke (AIS).

METHODS

From March 2014 to August 2015, consecutive first-ever AIS patients admitted to the Department of Emergency of our hospital were identified. Serum 25(OH) D levels were measured at admission. Functional outcome was evaluated at 6-month using the modified Rankin scale (m-Rankin). We used logistic regression models to assess the relationship between 25(OH) levels and risk of recurrent stroke or functional outcome.

RESULTS

We recorded 277 stroke patients. There were significantly negative correlation between levels of 25(OH) D and NHISS (P<0.001), and the infarct volume (P< 0.001). Thirty-one patients (11.9%) had a stroke recurrence, while 82 patients (29.6) were with poor functional outcomes. In multivariate logistic regression analyses, serum 25(OH) D level was an independent marker of poor functional outcome and stroke recurrence [odds ratio (OR) 2.55 (1.38-3.96) and 3.03(1.65-4.12), respectively, P<0.001 for both, adjusted for NHISS, other predictors and vascular risk factors] in patients with AIS.

CONCLUSION

Our results demonstrate that low 25(OH) D levels are associated with stroke recurrence and support the hypothesis that 25(OH) D may serve as a biomarker of poor functional outcome after stroke.

Vitamin D3 transactivates the zinc and manganese transporter SLC30A10 via the Vitamin D receptor

Vitamin D3 regulates genes critical for human health and its deficiency is associated with an increased risk for osteoporosis, cancer, diabetes, multiple sclerosis, hypertension, inflammatory and immunological diseases. To study the impact of vitamin D3 on genes relevant for the transport and metabolism of nutrients and drugs, we employed next-generation sequencing (NGS) and analyzed global gene expression of the human-derived Caco-2 cell line treated with 500nM vitamin D3. Genes involved in neuropeptide signaling, inflammation, cell adhesion and morphogenesis were differentially expressed. Notably, genes implicated in zinc, manganese and iron homeostasis were largely increased by vitamin D3 treatment. An ∼10-fold increase in ceruloplasmin and ∼4-fold increase in haptoglobin gene expression suggested a possible association between vitamin D and iron homeostasis. SLC30A10, the gene encoding the zinc and manganese transporter ZnT10, was the chiefly affected transporter, with ∼15-fold increase in expression. SLC30A10 is critical for zinc and manganese homeostasis and mutations in this gene, resulting in impaired ZnT10 function or expression, cause manganese intoxication, with Parkinson-like symptoms. Our NGS results were validated by real-time PCR in Caco-2 cells, as well as in duodenal biopsies taken from healthy human subjects treated with 0.5μg vitamin D3 daily for 10 days. In addition to increasing gene expression of SLC30A10 and the positive control TRPV6, vitamin D3 also increased ZnT10 protein expression, as indicated by Western blot and cytofluorescence. In silico identification of potential vitamin D responsive elements (VDREs) in the 5'-flanking region of the SLC30A10 promoter and dual-luciferase reporter assay showed enhanced promoter activity in the presence of vitamin D receptor (VDR) and retinoid X receptor (RXR) constructs, as well as vitamin D3, but not when one of these factors was absent. Electrophoretic mobility shift assay (EMSA) and competition EMSA revealed binding of select sequences, namely, nt -1623/-1588 and nt -1758/-1723 relative to the transcription start site, to VDR-containing nuclear extracts. In conclusion, we have shown that vitamin D3 transactivates the SLC30A10 gene in a VDR-dependent manner, resulting in increased ZnT10 protein expression. Because SLC30A10 is highly expressed in the small intestine, it is possible that the control of zinc and manganese systemic levels is regulated by vitamin D3 in the intestine. Zinc, manganese and vitamin D are important for bone metabolism and brain health. Future examination of a possible role for supplementation or chelation of zinc and manganese, alongside vitamin D3 administration, will further our understanding of its potential benefit in the treatment of specific illnesses, such as osteoporosis and Parkinson's disease.

Vitamin D deficiency in Parkinson's disease patients with orthostatic hypotension

OBJECTIVES

The purpose of our study was to investigate the associations between serum vitamin D3 levels and orthostatic hypotension (OH) in patients with Parkinson's disease (PD).

MATERIALS AND METHODS

Fifty-five patients with PD were enrolled in this study. Blood pressure (BP) measurements were gathered while the patients were in the supine position and while standing up. Then, the patients were divided into two groups: PD patients with and without OH. We compared the levels of serum 25-hydroxyvitamin D3 and 1, 25-dihydroxyvitamin D3 (calcitriol) between the two groups.

RESULTS

Serum 25-hydroxyvitamin D and calcitriol levels were significantly decreased in patients with OH compared with those without OH. The systolic and diastolic BPs and symptom severities significantly negatively correlated with the serum 25-hydroxyvitamin D and calcitriol levels.

CONCLUSIONS

Although the underlying mechanism for this association is not fully understood, our results suggest that low vitamin D status is associated with OH in patients with PD.

Vitamin D is Not a Protective Factor in ALS

AIMS

Vitamin D deficiency has been associated with poorer prognosis in ALS. Better understanding of the role of vitamin D in ALS is needed to determine whether trials of systematic supplementation are justified. Our aim was to report vitamin D levels during the course of ALS and to evaluate its relationship with clinical parameters at diagnosis and with disease progression.

METHODS

We prospectively collected vitamin D serum concentrations from 125 consecutive ALS patients. Cox proportional hazard models analyzed the relationship between vitamin D concentrations, clinical parameters, and survival.

RESULTS

The mean vitamin D concentration was below our laboratory's lower limit of normal (P < 0.0001) and did not change during the course of the disease. The concentrations were higher in patients with bulbar onset (P = 0.003) and were negatively associated with body mass index (BMI) (P = 0.0095). Models with ALSFRS-R (ALS Functional Rating Scale-Revised) and BMI as a covariates showed that vitamin D concentrations predicted worse prognosis.

CONCLUSION

The distribution of vitamin D concentrations in our cohort was consistent with previous reports. Surprisingly, we noted a negative effect of higher vitamin D levels on prognosis in ALS. More detailed research is warranted to determine whether manipulation of vitamin D could be beneficial to patients.

Prognostic value of serum 25-hydroxyvitamin D in patients with stroke

We aimed to evaluate the association between 25-hydroxyvitamin D [25(OH) D] levels and both clinical severity at admission and outcome at discharge in patients with acute ischemic stroke (AIS). From June 2012 to October 2013, consecutive first-ever AIS patients admitted to the Department of Emergency of The Fourth Affiliated Hospital of Harbin Medical University, China were identified. Clinical information was collected. Serum 25(OH) D levels were measured at baseline. Stroke severity was assessed at admission using the National Institutes of Health Stroke Scale (NIHSS) score. Functional outcome was evaluated at discharge using the modified Rankin scale (m-Rankin). Multivariate analyses were performed using logistic regression models. During the study period, 326 patients were diagnosed as AIS and were included in the analysis. Serum 25(OH) D levels reduced with increasing severity of stroke as defined by the NIHSS score. There was a negative correlation between levels of 25(OH) D and the NIHSS (r = - 0.389, P = 0.000). In multivariate analyses, serum 25(OH) D level was an independent prognostic marker of discharge favorable functional outcome and survival [odds ratio 3.96 (2.85-7.87) and 3.36 (2.12-7.08), respectively, P = 0.000 for both, adjusted for NHISS, other predictors and vascular risk factors] in patients with AIS. Serum 25(OH) D levels are a predictor of both severity at admission and favorable functional outcome in patients with AIS. Additional research is needed on vitamin D supplementation to improve the outcome of post-stroke patients.

Is high prevalence of vitamin D deficiency a correlate for attention deficit hyperactivity disorder?

The aim of the study was to determine the association between vitamin D and attention deficit hyperactivity disorder (ADHD), and difference in the level of vitamin D in ADHD children and control. This a case-control study carried out in school health and primary health care clinics. A total of 1,331 children and adolescents who were diagnosed with ADHD based on clinical criteria and standardized questionnaires were enrolled in this study and were matched with 1,331 controls, aged 5-18 years old. Data on body mass index (BMI), clinical biochemistry variables including serum 25-hydroxyvitamin D were collected. The study found significant association between ADHD and vitamin D deficiency after adjusting for BMI and sex (adj. OR 1.54; 95 % CI 1.32-1.81; P < 0.001). Majority of the ADHD children were in the age group 5-10 years (40.7 %), followed by 11-13 years (38.4 %). The proportion of BMI <85th percentile was significantly over represented in ADHD group as compared to healthy control (87.8 vs. 83 %; P < 0.001, respectively), while on the other hand, BMI >95th percentile was over represented in the control than ADHD group (7.6 vs. 4.6 %; P < 0.001, respectively). Mean values of vitamin D (ng/mL) were significantly lower in ADHD children (16.6 ± 7.8) than in healthy children (23.5 ± 9.0) (P < 0.001). There was significant correlation between vitamin D deficiency and age (r = -0.191, P = 0.001); calcium (r = 0.272, P = 0.001); phosphorous (r = 0.284, P = 0.001); magnesium (r = 0.292, P = 0.001); and BMI (r = 0.498, P = 0.001) in ADHD children. The vitamin D deficiency was higher in ADHD children compared to healthy children.

Predict attention deficit hyperactivity disorder? Evidence -based medicine

Background:

Attention deficit hyperactivity disorder (ADHD) is the most common behavioral disorders in children and recent studies reported a relationship between low levels of Vitamin D and incidence of ADHD.

Aim:

The aim of this study was to investigate the association between vitamin D deficiency and attention deficit hyperactivity disorder (ADHD). Also, to study the impact and role of vitamin D on the development of ADH in children.

Design:

This is a case-control study which was conducted in children below 18 years of age from June 2011 to May 2013 at the School Health and Primary Health care Clinics, Qatar.

Methods and subjects:

The study was based on 1,331 cases and 1,331 controls. The data collection instrument included socio-demographic & clinical data, physician diagnosis family history, BMI, and serum 25(OH) vitamin D, calcium, albumin, billirubin, magnesium, calcium, cholesterol, urea, triglyceride and phosphorus. Descriptive and univariate statistical analysis were performed.

Results:

Of the total number of 3470 children surveyed, 1331 of ADHD and 1,331 of healthy children gave their consent to participate in this study. The mean age (± SD, in years) for ADHD versus control children was 10.63±3.4 vs. 10.77±3.4. Overweight (7.7% vs 9.4%) and obesity (4.6% vs 7.7%) were significantly lower in ADHD children compared to their counterparts (P=0.001). Vitamin D deficiency was considerably higher in ADHD children compared to healthy children. The mean value of vitamin D in ADHD children was much lower than the normal value and there was a significant difference found in the mean values of vitamin D between ADHD (16.6±7.8 with median 16) and control children (23.5±9.9) (p<0.0001) and with median 23 (p = 0.006). Mean values of Calcium and phosphorous were significantly higher in control compared to ADHD children (p<0.001). 1331 of all ADHD children had 19.1% had severe vitamin D deficiency (< 10 ng/ml), 44.9% has moderate insufficient levels (between 10-20 ng/ml), 27.3% has mild insufficient levels (between 20-30 ng/ml) and only 8.1% of ADHD had sufficient serum vitamin D levels (>30 ng/ml). Multivariate logistic regression analysis revealed that household income, poor relationship between parents, mothers’ occupation, consanguinity, BMI in percentiles, low duration of time under sun light, physical activity, low serum calcium level and low vitamin D level were considered as the main risk factors associated with the ADHD after adjusting for age, gender and other variables.

Conclusion:

The study showed that vitamin D deficiency was higher in ADHD children compared to healthy children. Supplementing infants with vitamin D might be a safe and effective strategy for reducing the risk of ADHD, but, further genomic and some other test and relevant studies need to be done.