Cerebrospinal fluid vitamin D-binding protein as a new biomarker for the diagnosis of meningitis

Microglia-Derived Vitamin D Binding Protein Mediates Synaptic Damage and Induces Depression by Binding to the Neuronal Receptor Megalin

Vitamin D binding protein (VDBP) is a potential biomarker of major depressive disorder (MDD). This study demonstrates for the first time that VDBP is highly expressed in core emotion-related brain regions of mice susceptible to chronic unpredictable mild stress (CUMS). Specifically, the overexpression of microglia (MG)-derived VDBP in the prelimbic leads to depression-like behavior and aggravates CUMS-induced depressive phenotypes in mice, whereas conditional knockout of MG-derived VDBP can reverse both neuronal damage and depression-like behaviors. Mechanistically, the binding of MG-derived VDBP with the neuronal receptor megalin mediates the downstream SRC signaling pathway, leading to neuronal and synaptic damage and depression-like behaviors. These events may be caused by biased activation of inhibitory neurons and excitatory-inhibitory imbalance. Importantly, this study has effectively identified MG-derived VDBP as a pivotal mediator in the interplay between microglia and neurons via its interaction with the neuronal receptor megalin and intricate downstream impacts on neuronal functions, thus offering a promising therapeutic target for MDD.

Impact of gene polymorphisms involved in the vitamin D metabolic pathway on the susceptibility to and severity of autism spectrum disorder

This study explores the association between genetic variations in the vitamin D pathway and autism spectrum disorder (ASD) susceptibility and severity in Thai children. A total of 276 participants, including 169 children with ASD and 107 healthy controls, were recruited. Genotyping of vitamin D pathway genes (CYP2R1, CYP27B1, GC, and VDR) was conducted using TaqMan-based real-time PCR, while serum vitamin D levels were measured by chemiluminescence immunoassay. ASD severity was assessed via the Childhood Autism Rating Scale, 2nd Edition. Results reveal that the VDR gene (ApaI) rs7975232 is linked to a reduced ASD risk. In contrast, the GC gene rs7041 (A > C) polymorphism shows a significant association with increased ASD risk and severity, particularly in individuals with both the GC gene polymorphism and vitamin D insufficiency. Additionally, there was a higher prevalence of the GC1s isoform and GC1s-GC1s haplotype in children with ASD, associated with ASD severity. This study identified that individuals possessing GC rs7041 C alleles and the GC1s genotype (rs7041C/rs4588G) exhibit an increased susceptibility to and more severity of ASD. Further studies with larger cohorts are essential to fully understand these genetic polymorphisms' roles.

Maternal vitamin D status and attention deficit hyperactivity disorder (ADHD), an under diagnosed risk factor; A review

Vitamin D is important to mediate several brain processes such as proliferation, apoptosis, and neurotransmission in early stages of life. Vitamin D deficiency during critical periods of development can lead to persistent brain alterations. Vitamin D homeostasis during pregnancy is affected by two factors which includes an increase in mother’s calcitriol levels and an increase in mother’s Vitamin D Binding protein concentrations. Attention deficient hyperactivity disorder (ADHD) is an outcome of a complicated interaction between genetic, environmental, and developmental traits, and genetic factors cover about 80% of the cases. The efficiency of the immune system can be altered by a deficiency of Vitamin D in maternal body and maternal stress during gestation such as perinatal depression. Studies have proved that during gestation if there is a deficiency of vitamin D in maternal body, it can influence the brain development of the fetus and can also alter the synthesis of the brain-derived neurotropic factor. The current manuscript has been compiled to elaborate different factors which are associated with ADHD particularly focusing on the relationship of vitamin D deficiency in mothers. References material was selected from NCBI (PUBMED), Science direct, Google scholar, Publons etc. Using the terms ADHD, Vitamin D and Maternal nutritional status. Although, controversial relationship was found between the deficiency of Vitamin D level in pregnant women and development of ADHD in children but more controlled trials are required for future direction as well as to rule out other associated causes.

Immunologic biomarkers for bacterial meningitis

Meningitis is defined as the inflammation of the meninges that is most often caused by various bacterial and viral pathogens, and is associated with high rates of mortality and morbidity. Early detection of bacterial meningitis is essential to appropriate antibiotic therapy. Alterations in immunologic biomarkers levels have been considered the diagnostic approach in medical laboratories for the identifying of infections. The early increasing immunologic mediators such as cytokines and acute phase proteins (APPs) during bacterial meningitis have made they significant indicators for laboratory diagnosis. Immunology biomarkers showed wide variable sensitivity and specificity values that influenced by different reference values, selected a certain cutoff point, methods of detection, patient characterization and inclusion criteria, as well as etiology of meningitis and time of CSF or blood specimens' collection. This study provides an overview of different immunologic biomarkers as diagnostic markers for the identification of bacterial meningitis and their efficiencies in the differentiating of bacterial from viral meningitis.

GC1f Vitamin D Binding Protein Isoform as a Marker of Severity in Autism Spectrum Disorders

Autism spectrum disorders (ASD) are characterized by a wide spectrum of clinical, behavioral, and cognitive manifestations. It is, therefore, crucial to investigate possible biomarkers associated with specific ASD phenotypes. Ample literature suggests a possible role for vitamin D (VD) in influencing ASD clinical phenotypes. We analyzed three vitamin D binding protein gene (DBP) functional polymorphisms (rs2282679, rs7041, and rs4588), which are involved in the modulation of vitamin D serum concentration in 309 ASD children and 831 healthy controls. Frequency comparisons of single nucleotide polymorphisms (SNPs) alleles, genotypes, and GC isoforms (GC1f, G1s, and GC2)—generated by the combination of rs7041 and rs4588 alleles—were correlated with ASD diagnostic, behavioral, and functioning scales. The GC1f isoform was significantly more frequent in ASD compared with controls (18.6% vs. 14.5% pc = 0.02). Significantly higher scores for item 15 of the Childhood Autism Rating Scale (CARS) and lower ones for the Children’s Global Assessment Scale (CGAS) functioning scales were seen in ASD carrying the GC1f isoform. In GC phenotype analysis, a gradient of severity for overall CARS scores and CARS item 15 was observed, with scores decreasing according to the presence of GC1f-GC1f > GC1f-GC1s > GC1s-GC1s > GC1f-GC2 > GC2-GC2 isoforms. Similarly, lower CGAS scores were seen in carriers of the GC1f-GC1f isoform, whereas higher scores were present in those carrying GC2-GC2 (p = 0.028). This is the first study to evaluate possible relationships between GC variants and the different aspects of ASD in Italian ASD children. Results, although needing to be validated in ampler cohorts, suggest that the GC1f isoform could be a marker of severity in ASD that may be useful in establishing the intensity of therapeutic and rehabilitative protocols.

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.

Quantitative proteomic analysis of cerebrospinal fluid reveals CD163, A2M and full-length APP as potential diagnostic biomarkers of paediatric bacterial meningitis

Background

Bacterial meningitis (BM) is a life-threatening infectious disease of the central nervous system in infants and children. To date, no diagnostic methods for the early and precise diagnosis of paediatric BM have been developed.

Methods

A label-free cerebrospinal fluid (CSF) quantitative proteomic analysis of 8 patients with confirmed or suspected BM, 9 patients with confirmed or suspected viral meningitis (VM) and 6 non-CNS-infected hospital patients was performed via high-resolution LC–MS/MS.

Results

Our CSF proteomic analysis allowed the identification of critical differences between the BM and non-BM groups. Compared to the proteomes of the non-BM groups, the proteome of the paediatric BM group was characterized by upregulation of complement and coagulation cascades, regulation of IGF transport, uptake by IGF-binding proteins and acute inflammatory response, downregulation of developmental growth, and metabolism of carbohydrates. Moreover, the levels of CD163, A2M and full-length APP in CSF showed excellent diagnostic performance for paediatric BM, with AUC values of 0.911 (95% CI: 0.839–0.984), 0.908 (95% CI: 0.816–1.000) and 0.944 (95% CI: 0.86, 1.000), respectively. Among them, A2M and full-length APP are reported here for the first time as potential diagnostic biomarkers of BM. The findings imply that peptidase regulator activity plays an important role in BM and provide potential novel targets for precision medicine in paediatric BM.

Conclusions

CD163, A2M and full-length APP are validated as potential diagnostic biomarkers of paediatric BM.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12953-022-00191-5.

Vitamin D in Alzheimer's Disease: Low Levels in Cerebrospinal Fluid Despite Normal Amounts in Serum

BACKGROUND

Vitamin D insufficiency has been suggested as a dementia risk factor.

OBJECTIVE

In this cross-sectional, explorative study we investigated whether levels of vitamin D in cerebrospinal fluid (CSF) are lower in patients with positive biomarkers of Alzheimer's disease (AD) compared to cognitively healthy controls and whether polymorphisms of the vitamin D receptor (VDR) gene, FokI, BsmI, ApaI, and TaqI, are associated with levels of vitamin D in CSF and cognition.

METHODS

We included 100 patients≥65 years assessed for cognitive impairment and 76 cognitively healthy controls. Levels of 25-hydroxyvitamin D (25(OH)D) in both serum and CSF, and VDR polymorphisms were analyzed.

RESULTS

The mean level of 25(OH)D in serum was 78.6 (SD 28.9) nmol/l. While serum levels of 25(OH)D were not significantly different between the groups, CSF levels of 25(OH)D were significantly lower in patients with positive AD core biomarkers (p = 0.001) compared to patients without such biomarkers. Individuals with the BsmI major homozygote genotype had significantly lower results on a 10-word delayed recall test (p = 0.044) and verbal fluency test (p = 0.013), and individuals with the TaqI major homozygote genotype had significantly lower results on a verbal fluency test (p = 0.030) compared to individuals with the corresponding minor homozygote genotype.

CONCLUSION

Patients with positive AD core biomarkers have low CSF levels of 25(OH)D, despite sufficient serum levels. CSF levels of 25(OH)D do not seem to be affected by any of the four VDR gene polymorphisms. TaqI and BsmI major homozygote genotypes might be at increased risk for development of cognitive decline.

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.

Clinical utility of cerebrospinal fluid vitamin D-binding protein as a novel biomarker for the diagnosis of viral and bacterial CNS infections

Background

Rapid and accurate diagnosis of central nervous system (CNS) infections is important, and laboratory tests help diagnose CNS infections. Even when the patient has symptoms, laboratory tests often do not reveal any specific findings. The potential of vitamin D-binding protein (VDBP) to be used as a biomarker for viral and bacterial CNS infections was studied.

Methods

A total of 302 subjects with suspected CNS infection who underwent lumbar puncture were included. Clinical and laboratory data were collected retrospectively. VDBP levels were measured in the cerebrospinal fluid (CSF) samples. Genotyping for the GC gene encoding VDBP was also performed. VDBP levels were analyzed and compared by CNS infection, pathogen, CSF opening pressure, and GC genotype.

Results

A CNS infection group (n = 90) and a non-CNS infection group (n = 212) were studied. In terms of its receiver operating characteristic, CSF VDBP showed an area under the curve of 0.726 for the diagnosis of CNS infection. CSF VDBP levels were significantly different between the CNS infection and non-infection groups. The CNS infection group with enterovirus showed a statistically lower distribution of CSF VDBP levels than the other virus groups. The group with CSF opening pressure > 25 cmH₂O showed higher CSF VDBP levels than the other groups. There was no significant difference in GC gene allele distribution between the CNS infection and non-infection groups.

Conclusions

CSF VDBP levels were increased in patients with CNS infection. The CSF VDBP showed potential as a new biomarker for viral and bacterial CNS infections.

Vitamin D Measurement, the Debates Continue, New Analytes Have Emerged, Developments Have Variable Outcomes

The demand for measurement of vitamin D metabolites for clinical diagnosis and to advance our understanding of the role of vitamin D in human health has significantly increased in the last decade. New developments in technologies employed have enabled the separation and quantification of additional metabolites and interferences. Also, developments of immunoassays have changed the landscape. Programmes and materials for assay standardisation, harmonisation and the expansion of the vitamin D external quality assurance scheme (DEQAS) with the provision of target values as measured by a reference measurement procedure have improved standardisation, quality assurance and comparability of measurements. In this article, we describe developments in the measurement of the commonly analysed vitamin D metabolites in clinical and research practice. We describe current analytical approaches, discuss differences between assays, their origin, and how these may be influenced by physiological and experimental conditions. The value of measuring metabolites beyond 25 hydroxyvitamin D (25(OH)D), the marker of vitamin D status, in routine clinical practice is not yet confirmed. Here we provide an overview of the value and application of the measurement of 1,25 dihydroxyvitamin D, 24,25 dihydroxyvitamin D and free 25OHD in the diagnosis of patients with abnormalities in vitamin D metabolism and for research purposes.