Vitamin D and 1,25-dihydroxyvitamin D3 as modulators in the immune system

Vitamin D efficacy in type 1 and type 2 diabetes

It is well known that vitamin D has a profound effect on calcium and bone metabolism, but its influence on other organs (extraskeletal effect) has been proposed. Consistently, vitamin D deficiency is associated with an increased incidence of various diseases, including type 1 and type 2 diabetes, as reported by many observational studies. However, there has been no consensus on whether vitamin D deficiency is a causative factor in the incidence of diabetes mellitus. There have been no randomized controlled trials (RCTs) aimed at preventing the onset of type 1 diabetes with vitamin D intake. In addition, the results of RCTs evaluating the preventive effect of vitamin D supplementation on type 2 diabetes development have been inconsistent. The recent observational studies, randomized controlled trials, and meta-analyses are confirming that vitamin D or active vitamin D administration is effective in preventing the incident of type 1 and type 2 diabetes.

Relationship Between Vitamin D Levels and β Cell Function and Insulin Resistance

Background This study aimed to determine the relationship between vitamin D levels and β cell function and insulin resistance in patients with diabetes, glucose tolerance disorder, or impaired fasting glucose. Methodology A total of 75 outpatients (55 females and 20 males) between the ages of 30 and 65 years were included in the study. There were 25 healthy individuals, 25 individuals with prediabetes, and 25 individuals with diabetes. The Homeostasis Model Assessment (HOMA) score was used to evaluate insulin resistance. Results The mean levels of vitamin 25(OH)D among the groups included in the study were 35 ± 16.9 nmol/L in the control group, 44.5 ± 34.5 nmol/L in the prediabetes group, and 35.7 ± 13.1 nmol/L in the diabetes group. There were no significant differences. The mean level of vitamin 1.25(OH)₂D₃ was 15.95 ± 8 pg/mL in the control group, 18.4 ± 7.5 pg/mL in the prediabetes group, and 21.5 ± 7.9 pg/mL in the diabetes group. While the levels of vitamin 25(OH)D were similar between the groups, the levels of vitamin 1,25(OH)₂D₃  were significantly higher in the diabetes group. Considering all individuals, no significant difference was found between the vitamin 25(OH)D and glucose levels at minutes 0, 30, 60, 90, and 120. While there was a significant positive relationship between the 1,25(OH)₂D₃ vitamin and glucose levels at minutes 0, 30, 60, and 90, there was no significant relationship between the levels at minute 120. When the 1,25(OH)₂D₃ vitamin and HOMA insulin resistance and HOMA β scores were compared, a significant positive relationship was found between the 1,25(OH)₂D₃ vitamin and HOMA β levels. Conclusions In our study, there was no significant difference between the groups (control, prediabetes, and diabetes) in 25(OH)D levels. Similarly, there was no significant relationship between the 25(OH)D levels and insulin sensitivity and resistance between the groups. The positive relationship identified between the 1,25(OH)₂D₃ vitamin levels and the glucose concentration at minutes 0, 30, 60, and 90 and the higher 1,25(OH)₂D₃ vitamin levels in the diabetes group compared to the control group in our study can be interpreted as the effort of the organism to prevent glucose-induced β-cell apoptosis.

Correlation between Serum 25-Hydroxyvitamin D Level and Depression among Korean Women with Secondary Amenorrhea: A Cross-Sectional Observational Study

Vitamin D deficiency is considered a major public health problem worldwide and has been reported as having an association with depression. However, studies on the association between vitamin D deficiency and depressive symptoms in secondary amenorrhea (SA) patients are still scarce. This study examined the relationship between serum 25-hydroxyvitamin D (25(OH)D) levels and depressive symptoms among Korean women with SA. In this cross-sectional observational study, 78 patients with SA were initially recruited. Clinical and biochemical parameters, including serum 25(OH)D level, were measured. Data from 63 SA patients who met the study inclusion criteria and completed psychiatric assessments were finally analyzed. We analyzed their association with depression using a hierarchical regression model. The average serum 25(OH)D level was 34.40 ± 24.02 ng/mL, and 41.3% of the women with SA were vitamin D-deficient (<20 ng/mL). The total score of the Korean version of the Hamilton Depression Rating Scale (K-HDRS) was negatively related to serum 25(OH)D levels, free testosterone, and serum anti-Müllerian hormone (AMH) after adjusting for age and BMI (r = −0.450, p < 0.001; r = −0.258, p = 0.045; and r = −0.339, p = 0.006, respectively). Serum 25(OH)D levels and AMH levels were the most powerful predictors of depressive severity when using the K-HDRS in SA patients (β = −0.39, p < 0.005; β = −0.42, p < 0.005, respectively). This study showed that low serum 25(OH)D levels were associated with the severity of depressive symptoms in SA patients. This observation suggests that the evaluation of vitamin D deficiency for the risk of depression may be necessary in patients with SA.

Single-nucleotide polymorphisms as important risk factors of diabetes among Middle East population

Diabetes is a chronic metabolic disorder that leads to the dysfunction of various tissues and organs, including eyes, kidneys, and cardiovascular system. According to the World Health Organization, diabetes prevalence is 8.8% globally among whom about 90% of cases are type 2 diabetes. There are not any significant clinical manifestations in the primary stages of diabetes. Therefore, screening can be an efficient way to reduce the diabetic complications. Over the recent decades, the prevalence of diabetes has increased alarmingly among the Middle East population, which has imposed exorbitant costs on the health care system in this region. Given that the genetic changes are among the important risk factors associated with predisposing people to diabetes, we examined the role of single-nucleotide polymorphisms (SNPs) in the pathogenesis of diabetes among Middle East population. In the present review, we assessed the molecular pathology of diabetes in the Middle East population that paves the way for introducing an efficient SNP-based diagnostic panel for diabetes screening among the Middle East population. Since, the Middle East has a population of 370 million people; the current review can be a reliable model for the introduction of SNP-based diagnostic panels in other populations and countries around the world.

Association of vitamin D receptor gene polymorphism with type 1 diabetes mellitus risk in children: A protocol for systematic review and meta-analysis

BACKGROUND

Recent genetic association studies showed that there are contradictory results on the relationship between vitamin D receptor (VDR) gene polymorphisms and type 1 diabetes mellitus (T1DM) risk in children. The purpose of this systematic review is to collect the currently available evidence to evaluate the relationship between VDR gene polymorphisms and the risk of T1DM in children.

METHODS

Such medical databases as Wanfang Data, Chinese Biomedical Literature Database, Chinese National Knowledge Infrastructure, Chongqing VIP Chinese Science and Technology Periodical Database, PubMed, Embase, and Web of Science were extensively searched for relevant literatures published before June 2021 with the focus on the relationship between VDR gene polymorphisms and the risk of T1DM in children. The risk of bias was evaluated as per the Newcastle-Ottawa Scale by 2 independent researchers. Meta-analysis was performed to quantify the relationship between VDR gene polymorphisms and T1DM risk in children.

RESULTS

The results of this meta-analysis would be submitted to a peer-reviewed journal for publication.

CONCLUSION

The relationship between VDR gene polymorphisms and T1DM risk in children is explored via this meta-analysis.

ETHICS AND DISSEMINATION

Ethical approval was not required for this study. The systematic review will be published in a peer-reviewed journal, presented at conferences, and shared on social media platforms.

OSF REGISTRATION NUMBER

DOI 10.17605/OSF.IO/Q8XA5.

Nutritional Support for Bariatric Surgery Patients: The Skin beyond the Fat

Body contouring surgery after the massive weight loss due to bariatric surgery deals with different kinds of complications. The aim of this review is to analyze the role that some nutrients may play in tissue healing after surgery, thus helping plastic surgeons to improve the aesthetic and health outcomes in massive weight loss patients under a multidisciplinary approach. As a matter of fact, preoperative nutritional deficiencies have been shown for vitamins and minerals in a large percentage of post-bariatric patients. Preoperative deficiencies mainly concern iron, zinc, selenium, and vitamins (both fat-soluble and water-soluble), but also total protein. During the postoperative period, these problems may increase because of the patients' very low intake of vitamins and minerals after bariatric surgery (below 50% of the recommended dietary allowance) and the patients' low compliance with the suggested multivitamin supplementation (approximately 60%). In the postoperative period, more attention should be given to nutritional aspects in regard to the length of absorptive area and the percentage of weight loss.

Association between vitamin D receptor polymorphisms and acute pancreatitis: A protocol for systematic review and meta analysis

BACKGROUND

Several studies have been performed to investigate the association between vitamin D receptor (VDR) gene polymorphism and acute pancreatitis, but the results are inconclusive. We conducted this meta-analysis for a precise estimation of the association between BsmI (rs1544410), ApaI (rs7975232), TaqI (rs731236), and FokI (rs2228570) polymorphisms and acute pancreatitis.

METHODS

Appropriate studies were retrieved by searching Web of Science, PubMed, Scopus, and Google scholar databases, until January 31, 2021. Two reviewers independently conducted data extraction and literature quality evaluation. Odds ratios and 95% confidence intervals were calculated to evaluate the strength of the association.All of the data were analyzed with Stata 16.0.

RESULTS

The results of this meta-analysis will be submitted to a peer-reviewed journal for publication.

CONCLUSIONS

This meta-analysis will summarize the association between BsmI, ApaI, TaqI, and FokI polymorphisms and the risk of acute pancreatitis.

ETHICS AND DISSEMINATION

Ethical approval was not required for this study. The systematic review will be published in a peer-reviewed journal, presented at conferences, and shared on social media platforms.

OSF REGISTRATION NUMBER

DOI 10.17605/OSF.IO/83W7R.

Correlation between serum 25-hydroxyvitamin D level and diabetic retinopathy: A protocol for systematic review and meta-analysis

BACKGROUND

Diabetic retinopathy is a common complication of diabetes with a high incidence, and vitamin D deficiency is associated with diabetic retinopathy. Serum 25-hydroxy vitamin D [25-hydroxy-vitamind, 25 (OH) D], a product of vitamin D in the body, is considered the best indicator of a person's vitamin D nutritional status, and can be determined by measuring the concentration of 25 (OH) D. The purpose of this study is to systematically evaluate the correlation between serum 25-hydroxy vitamin D levels and diabetic retinopathy.

METHODS

To search English databases (PubMed, Excerpta Medical Database (Embase), Web of Science, the Cochrane Library) and Chinese databases (Chinese National Knowledge Internet, Development, and Evaluation (CNKI), WanFang, Viper, Chinese Biomedical Literature Database) by computer about Clinical study on the correlation between serum 25-hydroxyvitamin D level and diabetic retinopathy from the establishment of the database to November 2020. Two researchers independently conducted data extraction and literature quality evaluation on the quality of the included studies, and meta-analysis is conducted on the included literatures using Stata12.0 and RevMan5.3 software.

CONCLUSION

In this study, the correlation between serum 25-hydroxyvitamin D level and diabetic retinopathy was systematically evaluated to provide an evidence-based basis for clinicians.

ETHICS AND DISSEMINATION

Private information from individuals will not be published. This systematic review also does not involve endangering participant rights. Ethical approval was not required. The results may be published in a peer-reviewed journal or disseminated at relevant conferences.

OSF REGISTRATION NUMBER

DOI 10.17605/OSF.IO/CQY94.

Cutaneous lymphomas and COVID-19: What is known so far?

The Coronavirus disease 2019 (COVID-19) pandemic spreads quickly all over the world. There are no sufficient data in the literature about COVID-19 infection and cutaneous lymphomas. This review sheds the light on what is known so far about COVID-19 with a cutaneous lymphoma perspective. Cutaneous T-cell lymphoma (CTCL) diagnosis does not represent a predisposing factor to viral infections and most of CTCL patients have indolent disease. However, physicians should be cautious with patients with aggressive primary cutaneous lymphomas and advanced CTCL. Different treatment strategies for cutaneous lymphomas should be taken into consideration during the COVID-19 pandemic. Thus, it is highly needed to estimate the benefit-to-risk ratio on a case-by-case basis.

Autoimmune thyroid disease and type 1 diabetes mellitus: same pathogenesis; new perspective?

Autoimmune thyroid disease (AITD) and type 1 diabetes mellitus (T1DM) are two common autoimmune diseases that can occur concomitantly. In general, patients with diabetes have a high risk of AITD. It has been proposed that a complex genetic basis together with multiple nongenetic factors make a variable contribution to the pathogenesis of T1DM and AITD. In this paper, we summarize current knowledge in the field regarding potential pathogenic factors of T1DM and AITD, including human leukocyte antigen, autoimmune regulator, lymphoid protein tyrosine phosphatase, forkhead box protein P3, cytotoxic T lymphocyte-associated antigen, infection, vitamin D deficiency, and chemokine (C-X-C motif) ligand. These findings offer an insight into future immunotherapy for autoimmune diseases.

Relationship of four vitamin D receptor gene polymorphisms with type 1 diabetes mellitus susceptibility in Kuwaiti children

Background

The incidence of type 1 diabetes mellitus (T1DM) in Kuwait is amongst the highest in the world. Vitamin D is considered to be involved in immune modulation and its deficiency contribute to autoimmune destruction of insulin producing beta cells in T1DM patients. Vitamin D has been shown to exert its effects via a nuclear vitamin D receptor (VDR) and therefore, VDR gene may be considered a candidate for T1DM susceptibility.

Methods

The genotypes of four VDR gene polymorphisms were determined in 253 Kuwaiti Arab T1DM patients and 214 healthy controls by PCR-RFLP analysis. Serum concentrations of three autoantibodies i.e. ICA (Islet cell autoantibody), GADA (Glutamic acid decarboxylase) and INS (Insulin autoantibody) were determined by radio-immunoassays.

Results

Statistically significant differences were detected between the genotypes of two VDR gene polymorphisms (FokI, C > T, rs10735810 and TaqI, C > T, rs731236) between T1DM patients and controls (P < 0.0001). In both, the frequency of variant alleles was considerably high in T1DM than in the controls. In contrast, the VDR gene ApaI (G > T, rs7975232) and BsmI (A > G, rs1544410) polymorphisms did not show association with T1DM. The homozygous variant genotypes of FokI, ApaI and TaqI polymorphisms show significant differences between various age-of-onset subgroups while no such association was detected in the case of BsmI polymorphism. Significant differences were also noted between heterozygous genotypes of all four polymorphisms especially between 4-6y and > 6y age-of-onset subgroups of T1DM patients. Three autoantibodies, ICA (Islet cell), GADA (glutamate decarboxylase) and INS (insulin) were positively associated to, varying degrees, with T1DM in Kuwaiti Arabs harboring different VDR gene polymorphism genotypes.

Conclusions

Our results demonstrate a significant effect of two VDR gene polymorphisms (FokI and TaqI) and three autoantibodies on genetic susceptibility of T1DM in Kuwaiti Arabs along with other factors.

Vitamin D, Inflammation and Immunity: Review of Literature and Considerations on Recent Translational and Clinical Research Developments

The most relevant and recent literature findings linking exposure to sunlight, Vitamin D (VD), inflammation and immune system in health and disease, are reviewed.

Reduced sunlight exposure determined hypo-vitaminosis D to be common among patients or even healthy subjects, especially at higher latitudes. Numerous studies support the hypothesis that VD insufficiency could contribute to the higher autoimmune diseases incidence in the same geographic areas.

In the present review, the ways in which VD was reported to influence immune system, contributing to organism homeostasis or disease development are addressed. In fact, some of the hormone activities were recognised to determine stimulation or inhibition of immune system components.

Several diseases, where an association with VD deficiency was studied, are summarised. Finally, the rationale for optimization of substitutive/additive therapy with VD analogues and the last innovations regarding these drugs are mentioned.

Vitamin D receptor gene polymorphism, serum 25-hydroxyvitamin D levels, and risk of vitiligo: A meta-analysis

OBJECTIVES

To explore the relationship among the vitamin D receptor (VDR) gene polymorphisms, serum 25-hydroxyvitamin D levels, and vitiligo.

METHODS

Databases including PubMed, Cochrane Library, Ovid, Web of Science, CNKI, SinoMed, and Wanfang Data were systematically searched. The association was assessed using odds ratios (ORs), standard mean difference (SMD), and 95% confidence intervals (CIs). The statistical tests were performed using Review Manager 5.3.3.

RESULTS

We identified a total of 17 studies. The relationship between VDR gene polymorphisms (BsmI, ApaI, TaqI, and FokI), serum 25 (OH)D levels, and incidence of vitiligo was investigated. The results of this meta-analysis showed that the dominant genetic model (CC+AC vs AA, P = .007, OR = 1.41, 95% CI = 1.10-1.80), recessive genetic model (CC vs AC+AA, P = .01, OR = 4.10, 95% CI = 1.36-12.35), and allelic contrast model (C vs A, P = .005, OR = 1.87, 95% CI = 1.21-2.90) of VDR Apal locus increased the risk of vitiligo, and BsmI, TaqI, and FokI loci and the risk of vitiligo have no obvious correlation. Serum 25 (OH)D deficiency was positively associated with the incidence of vitiligo (P < .0001, SMD = -0.94, 95% CI = -1.39, -0.48).

CONCLUSION

This meta-analysis revealed that VDR Apal polymorphism increased the susceptibility risk of vitiligo, and there is a positive correlation between serum 25 (OH)D deficiency and the incidence of vitiligo.

Single Nucleotide Polymorphisms in the Vitamin D Receptor Gene (VDR) May Have an Impact on Acute Pancreatitis (AP) Development: A Prospective Study in Populations of AP Patients and Alcohol-Abuse Controls

Vitamin D imbalance is suggested to be associated with the development of pancreatitis. Single nucleotide polymorphisms (SNPs), Apa-1, Bsm-1, Fok-1, and Taq-1, in the vitamin D receptor gene (VDR) are known in various diseases, but not yet in pancreatitis. The aim of this study was to explore possible associations of the four SNPs in the VDR receptor gene in a population of acute pancreatitis patients and alcohol-abuse controls, and to investigate the association with acute pancreatitis (AP) susceptibility. The study population (n = 239) included acute pancreatitis patients (n = 129) and an alcohol-abuse control group (n = 110). All patients met the Diagnostic and Statistical Manual of Mental Disorders (DSM IV) criteria for alcohol dependence. DNA was extracted from peripheral leukocytes and analyzed for VDR polymorphisms using a polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. Odd ratios (ORs) and 95% confidence intervals (CIs) were calculated using logistic regression analysis. To date, we have found allele T in Taq-1 (OR = 2.61; 95% CI: 1.68⁻4.03; p < 0.0001) to be almost three times more frequent in the AP group compared to the alcohol-abuse control patients. Polymorphism Taq-1 occurring in the vitamin D receptor may have an impact on the development of acute pancreatitis due to the lack of the protective role of vitamin D.

Vitamin D Receptor Gene Polymorphisms Associated with Childhood Autism

Background: Autism spectrum disorder (ASD) is a group of heterogeneous, behaviorally defined disorders whereby currently no biological markers are common to all affected individuals. A deregulated immune response may be contributing to the etiology of ASD. The active metabolite of vitamin D₃ has an immunoregulatory role mediated by binding to the vitamin D receptor (VDR) in monocyte, macrophages, and lymphocytes. The effects of vitamin D and interaction with the VDR may be influenced by polymorphism in the VDR gene. Methods: Genetic association of four different VDR polymorphisms (Apa-I, Bsm-I, Taq-I, Fok-I) associated with susceptibility to the development of autism in children was investigated. Results: We uniquely found an association between the presence of the T allele at position Taq-I and presence of the a allele at position Apa-I of the VDR gene with decreased ASD incidence. There was also an association between female gender and the presence of the T allele. We found no statistical significant correlation between VDR single nucleotide polymorphisms (SNPs) and vitamin D₃ concentration in serum of ASD children. Conclusion: Genetic polymorphism in two SNP in VDR may be correlated with development of ASD symptoms by influencing functionality of vitamin D₃ metabolism, while vitamin D₃ levels were not significantly different between ASD and non-ASD children.

Hypovitaminosis D in Patients Undergoing Shoulder Arthroplasty: A Single-Center Analysis

Vitamin D is recognized as an essential component in bone health, muscle function, and immune system regulation. This study sought to characterize the prevalence of hypovitaminosis D in patients undergoing total shoulder arthroplasty (TSA), reverse total shoulder arthroplasty (RSA), and shoulder hemiarthroplasty (HA). Between September 2013 and December 2014, a total of 218 patients undergoing TSA, RSA, and HA by a single surgeon were screened for hypovitaminosis D and retrospectively reviewed. Demographic variables and risk factors were recorded. Overall, 93 shoulder arthroplasty patients (43%) were vitamin D insufficient (<30 ng/mL) and 24 patients (11%) were vitamin D deficient (<20 ng/mL). Body mass index (BMI) had a significant effect on vitamin D levels; BMI of 30 kg/m(2) or greater was associated with lower vitamin D levels (31.5±12.1 ng/mL) compared with patients with a BMI of less than 30 kg/m(2) (36.2±15.7 ng/mL, P ≤.01). The absence of supplementation with vitamin D and calcium prior to serum testing was the most significant risk factor for hypovitaminosis D (odds ratio [OR], 8.234, P<.001). Age, gender, race, smoking status, American Society of Anesthesiologists (ASA) score, procedure, and surgical indication were not significant. This is the largest cohort of shoulder arthroplasty patients screened for hypovitaminosis D. Almost half (43%) of the study population was insufficient, and both the absence of supplementation prior to serum testing and BMI of 30 kg/m(2) or greater were found to be predictive of lower serum 25-hydroxyvitamin D levels. Given the extent of vitamin D involvement in normal musculoskeletal physiology, routine preoperative evaluation is merited. [Orthopedics. 2016; 39(4):e651-e656.].

Resolving Vitamin D Deficiency in the Preconception Period among High-Risk Reproductive Women: A Randomized Controlled Trial

Background:

Although vitamin D deficiency has been linked to potential complications in reproductive women, the recommended intake dosage of this vitamin in populations with high incidence of deficiency in preconception period has not been defined.

Objectives:

The study investigated the effect of consuming a dosage of 2000 IU/day oral vitamin D for 105 days, on serum levels of this vitamin in reproductive women.

Materials and Methods:

229 women with 18-35 years old, who were confirmed to be vitamin D deficient (vitamin D < 75 nmol/L), were randomized into the intervention and control groups and after 15 weeks consumption of the supplement and placebo, their serum samples were obtained.

Results:

At baseline the mean serum levels of vitamin D in the control group was 23.34 ± 15.87 nmol/L and in intervention group was 25.13 ± 18.46 nmol/L, that these values didn’t have any significant difference (P = 0.43), while after intervention, significant differences between the two groups was noticed (P < 0.001). The affecting factors to achieve normal range of vitamin D in the intervention group included basal amounts of vitamin D and two underlying factors based on questionnaire data: use of oral supplements (except vitamin D and calcium) in daily life and perfect sun exposure.

Conclusion:

This study showed positive effect of the 2000 IU/day oral vitamin D on the serum level elevation of this vitamin in reproductive women.

Vitamin D status and vitamin D receptor gene polymorphisms and susceptibility to type 1 diabetes in Egyptian children

BACKGROUND

Type 1 diabetes mellitus (T1DM) is recognized as a T-cell-mediated autoimmune disease. Vitamin D compounds are known to suppress T-cell activation by binding to vitamin D receptor (VDR); and thus, VDR gene polymorphisms may be related to T-cell-mediated autoimmune diseases. The aim of this study was to investigate the association between vitamin D status and VDR gene polymorphisms and T1DM.

MATERIALS AND METHODS

One hundred and twenty patients with T1DM and one hundred and twenty controls were enrolled in the study. VDR gene BsmI, FokI, ApaI and TaqI polymorphisms were determined using polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP). Serum 25-hydroxyvitamin D (25(OH)D) was determined using ELISA.

RESULT

Serum 25(OH)D levels revealed a vitamin D deficiency or insufficiency in 75% of the patients. The mean levels of vitamin D were significantly lower in patients as compared to their controls (P=<0.001). VDR BsmI Bb and bb genotypes and VDR FokI Ff and ff genotypes were associated with increased risk of T1DM (OR=2.3, 95% CI=1.3-4.2, P=0.005; OR=2.2, 95% CI=1.1-4.7, P=0.04; OR=1.8, 95% CI=1.03-3.04, P=0.04; OR=4.03, 95% CI=1.2-13.1, P=0.01 respectively), while the VDR ApaI and TaqI polymorphisms were not.

CONCLUSION

Our study indicated that vitamin D deficiency and VDR BsmI and FokI polymorphisms were associated with T1DM in Egyptian children.

A-1012G promoter polymorphism of vitamin D receptor gene is associated with psoriasis risk and lower allele-specific expression

Psoriasis is caused by a combination of genetic, immunologic, and environmental factors. The vitamin D receptor (VDR) is involved in antiproliferative and prodifferentiation pathways in keratinocytes and exerts immunosuppressive effects. We aimed to investigate possible associations between VDR polymorphisms and psoriasis susceptibility and to evaluate functional effects of potential psoriasis-associated polymorphisms. We genotyped 108 patients with psoriasis and 268 healthy controls at 5 VDR polymorphisms (A-1012G, FokI, BsmI, ApaI, and TaqI) by TaqMan allelic-discrimination real-time polymerase chain reaction. We found a significant increased overall risk of psoriasis for the VDR A-1012G promoter polymorphism (odds ratio [OR]=2.43, 95% confidence interval [CI]: 1.15-5.13; p=0.05). A significant higher frequency (p=0.035) of the A allele was found in psoriatic cases compared with controls. In a case-case analysis, a statistically significant association between A-1012G and family history emerged (p=0.033). Furthermore, a significant association of A-1012G risk genotypes with a lower expression of VDR mRNA emerged (p=0.0028). Our data show that VDR promoter A-1012G polymorphism is associated with psoriasis risk and suggest that this polymorphism may modulate psoriasis risk by affecting VDR expression.

Vitamin D status in diabetic Egyptian children and adolescents: a case-control study

Background

Recently, studies suggesting that vitamin D deficiency correlates with the severity and frequency of Type 1 (insulin-dependent) diabetes mellitus (T1DM) and that vitamin D supplementation reduces the risk of developing T1DM have been reported.

Objective

In this study, we aimed to assess vitamin D status in Egyptian children and adolescents with T1DM.

Methods

This was a case–control study including 80 T1DM diagnosed cases aged 6 to 16 years and 40 healthy children with comparable age and gender as the control group. For all subjects, serum 25 (OH) D levels were measured by ELISA, Serum parathyroid hormone (PTH) and serum insulin were measured by an electrochemiluminesce immunoassay. Serum glucose, Glycosylated hemoglobin (HbA1c) levels and homeostasis model assessment of insulin resistance (HOMA-IR) were also assessed.

Results

Compared to the control group, serum vitamin D levels were not significantly lower in diabetic subjects (24.7 ± 5.6 vs 26.5 ± 4.8 ng/ml; P > 0.05). Among diabetic cases 44(55%) were vitamin D deficient; meanwhile 36(45%) cases had normal vitamin D level (P < 0.01). In addition, 26(32.5%) diabetic cases had 2ry hyperparathyroidism and 54(67.5%) cases had normal parathyroid hormone level; meanwhile, none of the control group had 2ry hyperparathyroidism (P < 0.01). Furthermore, we found a significant difference between vitamin D deficient diabetic cases and those with normal vitamin D level as regards HOMA-IR and diabetes duration (P < 0.01).

Conclusion

Public health message on the importance of vitamin D status; especially in diabetic children and adolescents, should be disseminated to the public.

Feeding the immune system

A well-functioning immune system is key to providing good defence against pathogenic organisms and to providing tolerance to non-threatening organisms, to food components and to self. The immune system works by providing an exclusion barrier, by identifying and eliminating pathogens and by identifying and tolerating non-threatening sources of antigens, and by maintaining a memory of immunological encounters. The immune system is complex involving many different cell types distributed throughout the body and many different chemical mediators some of which are involved directly in defence while others have a regulatory role. Babies are born with an immature immune system that fully develops in the first few years of life. Immune competence can decline with ageing. The sub-optimal immune competence that occurs early and late in life increases susceptibility to infection. Undernutrition decreases immune defences, making an individual more susceptible to infection. However, the immune response to an infection can itself impair nutritional status and alter body composition. Practically all forms of immunity are affected by protein-energy malnutrition, but non-specific defences and cell-mediated immunity are most severely affected. Micronutrient deficiencies impair immune function. Here, vitamins A, D and E, and Zn, Fe and Se are discussed. The gut-associated lymphoid tissue is especially important in health and well-being because of its close proximity to a large and diverse population of organisms in the gastrointestinal tract and its exposure to food constituents. Certain probiotic bacteria which modify the gut microbiota enhance immune function in laboratory animals and may do so in human subjects.

The association between plasma 25-hydroxyvitamin D3 concentrations, C-reactive protein levels, and coronary artery atherosclerosis in postmenopausal monkeys

OBJECTIVE

The aim of this study was to identify the potential relationships between plasma 25-hydroxyvitamin D(3) (25OHD(3)), C-reactive protein (CRP), coronary artery atherosclerosis (CAA), and coronary artery remodeling in monkeys consuming atherogenic diets.

METHODS

Female cynomolgus monkeys (n = 74) were fed a casein-lactalbumin (C/L)-based, moderately atherogenic diet for 12 months. They then consumed either a soy-based (n = 35) or C/L-based (n = 39) diet for 32 months. CRP concentrations were then determined, and monkeys underwent surgical menopause. Each diet group was then rerandomized to receive soy (n = 36) or C/L (n = 38). After 32 postmenopausal months, 25OHD(3), CRP, CAA, and coronary artery remodeling were determined. All monkeys received a woman's equivalent of 1,000 IU/day of vitamin D(3) and 1,200 mg/day of calcium throughout the study.

RESULTS

The premenopausal and postmenopausal dietary protein sources had no effect on postmenopausal 25OHD(3) concentrations (P = 0.6). Across treatment groups, there was a statistically significant inverse relationship between 25OHD(3) concentrations and CRP at necropsy (r = -0.35, P = 0.003). A significant inverse correlation between 25OHD(3) concentration and the change in CRP from premenopause to postmenopause was observed (r = -0.32, P = 0.007). The significant associations identified between plasma 25OHD(3) and CRP remained after controlling for postmenopausal diet. Those monkeys with a greater increase in CRP also had significantly more CAA and less ability to maintain normal lumens by remodeling.

CONCLUSIONS

Higher plasma concentrations of 25OHD(3) were associated with lower CRP. Lower CRP was associated with less coronary atherosclerosis and improved coronary artery remodeling. These findings suggest that 25OHD(3) concentrations are associated with an anti-inflammatory state and may support an association between oral vitamin D3 and cardioprotection.

Vitamin D: metabolism, molecular mechanisms, and mutations to malignancies

The potential protective effects of vitamin D against cutaneous carcinogenesis are still poorly understood. The inhibition, by vitamin D, of various cancers in in vitro and in vivo models has triggered detailed investigation of vitamin D effects on neoplastic behavior. Recent studies highlight that such neoplastic features as the tumor microenvironment, angiogenesis, DNA mutagenesis, and apoptosis are all connected to vitamin D metabolic pathways. This review discusses these connections. Vitamin D modulation of the cell cycle, DNA repair and apoptosis via its receptors (VDRs) may have a suppressive effect on skin cancer as some studies suggest. The regulation of multiple tumor signaling pathways by vitamin D may have an implication in cutaneous carcinogenesis and tumor progression to malignancy.

Potential benefits of vitamin D for patients with systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a complex multi-system autoimmune disease. Vitamin D deficiency has been proposed as an environmental trigger of disease onset and as a contributor to increased SLE activity. SLE patients are prone to develop vitamin D deficiency because of photosensitivity leading to sun avoidance and other sun protective measures. The impact of vitamin D on immune function previously seen in vitro and in cross-sectional studies has now been shown in prospective human studies, strengthening the evidence that there is a connection between SLE and vitamin D status. This review describes the role of vitamin D on immune function, prevalence of vitamin D deficiency in patients with SLE, identify risk factors for deficiency, describe the consequences of deficiency in SLE patients, and review current vitamin D recommendations for patients with SLE.

Potential mechanisms for the emerging link between obesity and increased intestinal permeability

Recently, increased attention has been paid to the link between gut microbial composition and obesity. Gut microbiota is a source of endotoxins whose increase in plasma is related to obesity and insulin resistance through increased intestinal permeability in animal models; however, this relationship still needs to be confirmed in humans. That intestinal permeability is subject to change and that it might be the interface between gut microbiota and endotoxins in the core of metabolic dysfunctions reinforce the need to understand the mechanisms involved in these aspects to direct more efficient therapeutic approaches. Therefore, in this review, we focus on the emerging link between obesity and increased intestinal permeability, including the possible factors that contribute to increased intestinal permeability in obese subjects. We address the concept of intestinal permeability, how it is measured, and the intestinal segments that may be affected. We then describe 3 factors that may have an influence on intestinal permeability in obesity: microbial dysbiosis, dietary pattern (high-fructose and high-fat diet), and nutritional deficiencies. Gaps in the current knowledge of the role of Toll-like receptors ligands to induce insulin resistance, the routes for lipopolysaccharide circulation, and the impact of altered intestinal microbiota in obesity, as well as the limitations of current permeability tests and other potential useful markers, are discussed. More studies are needed to reveal how changes occur in the microbiota. The factors such as changes in the dietary pattern and the improvement of nutritional deficiencies appear to influence intestinal permeability, and impact metabolism must be examined. Also, additional studies are necessary to better understand how probiotic supplements, prebiotics, and micronutrients can improve stress-induced gastrointestinal barrier dysfunction and the influence these factors have on host defense. Hence, the topics presented in this review may be beneficial in directing future studies that assess gut barrier function in obesity.

The Effects of Vitamin D Deficiency on Atrial Fibrillation

Background:

Vitamin D deficiency is associated with cardiovascular disease such as coronary artery disease, heart failure, and hypertension. Vitamin D deficiency activates the renin–angiotensin–aldosterone system, which affects the cardiovascular system. For this reason, it could be suggested that there is a relationship between vitamin D deficiency and atrial fibrillation (AF). In our study, we compared 25-hydroxyvitamin D (25-OHD) levels between nonvalvular AF, valvular AF, and control groups in sinus rhythm.

Method:

A total of 102 patients with nonvalvular chronic AF without any other cardiovascular disease (mean age 62.51 ± 5.88; group I) and 96 patients with AF, which is associated with mitral valve disease (mean age 61.51 ± 5; group II) were included in our study. Of all, 100 age-matched healthy people with sinus rhythm were accepted as control groups (mean age 61.35 ± 5.44). Routine biochemical parameters, 25-OHD and parathormone levels were performed.

Results:

Baseline characteristics of the study groups were comparable. Group I patients had a lower vitamin D level than group II and the control group (6.51 ± 4.89, 9.24 ± 7.39, and 11.18 ± 6.98 ng/mL, P < .001, respectively). In groups I and II, the patients’ left atrium diameter and systolic pulmonary artery pressure are higher than the control group.

Conclusion:

As a result, our study revealed a relationship between vitamin D deficiency and nonvalvular AF.

The effects of vitamin D on brain development and adult brain function

A role for vitamin D in brain development and function has been gaining support over the last decade. Multiple lines of evidence suggest that this vitamin is actually a neuroactive steroid that acts on brain development, leading to alterations in brain neurochemistry and adult brain function. Early deficiencies have been linked with neuropsychiatric disorders, such as schizophrenia, and adult deficiencies have been associated with a host of adverse brain outcomes, including Parkinson's disease, Alzheimer's disease, depression and cognitive decline. This review summarises the current state of research on the actions of vitamin D in the brain and the consequences of deficiencies in this vitamin. Furthermore, we discuss specific implications of vitamin D status on the neurotransmitter, dopamine.

Vitamin D, the placenta and pregnancy

Impaired vitamin D status is common to many populations around the world. However, data suggest that this is a particular problem for specific groups such as pregnant women. This has raised important questions concerning the physiological and clinical impact of low vitamin D levels during pregnancy, with implications for classical skeletal functions of vitamin D, as well as its diverse non-classical actions. The current review will discuss this with specific emphasis on the classical calciotropic effects of vitamin D as well as the less well established immunological functions of vitamin D that may influence pregnancy outcome. The review also describes the pathways that are required for metabolism and function of vitamin D, and the various clinical complications that have been linked to impaired vitamin D status during pregnancy.

VITAMIN D AND HUMAN PREGNANCY

At the end of 2007, Time magazine listed the “benefits of vitamin D” as one of its top 10 medical breakthroughs for that year. Since then there has been a remarkable upsurge of interest in vitamin D, with new research advances seemingly published on a weekly basis. In particular, there has been increasing awareness of the variability of vitamin D status in populations across the globe and, significantly, a growing debate about the need for revised parameters for vitamin D supplementation. Although sub-optimal vitamin D is likely to be a widespread problem for 21stcentury societies, it is also clear that some groups are at much greater risk of low vitamin D status. Prominent amongst these are pregnant women and the aim of the following review article will be to discuss this problem in further detail with specific emphasis on its potential physiological and clinical impact.

The seasonality of pandemic and non-pandemic influenzas: the roles of solar radiation and vitamin D

OBJECTIVES

Seasonal variations in ultraviolet B (UVB) radiation cause seasonal variations in vitamin D status. This may influence immune responses and play a role in the seasonality of influenza.

METHODS

Pandemic and non-pandemic influenzas in Sweden, Norway, the USA, Singapore, and Japan were studied. Weekly/monthly influenza incidence and death rates were evaluated in view of monthly UVB fluences.

RESULTS

Non-pandemic influenzas mostly occur in the winter season in temperate regions. UVB calculations show that at high latitudes very little, if any, vitamin D is produced in the skin during the winter. Even at 26°N (Okinawa) there is about four times more UVB during the summer than during the winter. In tropical regions there are two minor peaks in vitamin D photosynthesis, and practically no seasonality of influenza. Pandemics may start with a wave in an arbitrary season, while secondary waves often occur the following winter. Thus, it appears that a low vitamin D status may play a significant role in most influenzas.

CONCLUSIONS

In temperate latitudes even pandemic influenzas often show a clear seasonality. The data support the hypothesis that high fluences of UVB radiation (vitamin D level), as occur in the summer, act in a protective manner with respect to influenza.

Vitamin D and host resistance to infection? Putting the cart in front of the horse

Vitamin D is being touted as an anti-infective agent and it has even been suggested that vitamin D supplementation could be effective against the H1N1 influenza virus. The claims are largely based on the ability of vitamin D to induce antibacterial peptides and evidence that the immune system produces active vitamin D (1,25(OH)(2)D(3)) in situ. While there are many examples of immune production of 1,25(OH)(2)D(3) in vitro, there is little in vivo evidence. In addition, it is not clear what role immune production of 1,25(OH)(2)D(3) has on the course of disease. Vitamin D and 1,25(OH)(2)D(3) inhibit T helper type 1 (Th1)/Th17-mediated immune responses and autoimmune diseases by acting on the innate and acquired immune system to inhibit the function of Th1 and Th17 cells. Th1 and Th17 cells are important in host resistance to many infections including tuberculosis (TB) caused by Mycobacterium tuberculosis. Paradoxically the innate immune system is induced to produce antibacterial peptides that are effective against TB in vitro. Data from several models of infection have so far not supported a role for vitamin D in affecting the course of disease. There is also very little evidence that vitamin D affects the course of human TB infection. Experiments have not been done in cells, mice or humans to evaluate the effect of vitamin D on influenza virus. At this time it would be premature to claim that vitamin D has an effect on TB, influenza or any other infection.

Maternal intake of vitamin D during pregnancy and risk of advanced beta cell autoimmunity and type 1 diabetes in offspring

AIMS/HYPOTHESIS

We evaluated the intake of vitamin D by pregnant Finnish women and examined associations between maternal intake of vitamin D and the development of advanced beta cell autoimmunity and type 1 diabetes in their offspring.

METHODS

The research was carried out within the Diabetes Prediction and Prevention study (DIPP), which is a population-based birth cohort of infants at genetic risk of type 1 diabetes. Mothers of 3,723 infants born between 1997 and 2002 completed a validated 181-item food frequency questionnaire, which included questions on dietary supplements. The offspring were observed at 3 to 12 month intervals for the appearance of autoantibodies associated with type 1 diabetes and for the development of clinical type 1 diabetes.

RESULTS

Maternal mean daily intake of vitamin D was 5.1 microg from food and 1.3 microg from supplements. The maternal intake of vitamin D, either from food or from supplements, was not associated with the risk of advanced beta cell autoimmunity/type 1 diabetes in offspring (HR [95% CI] for intake of vitamin D from food 1.25 [0.80-1.95], for vitamin D intake from supplements 1.05 [0.95-1.16]), or with the risk of type 1 diabetes alone (HR [95% CI] for intake of vitamin D from food 0.84 [0.41-1.72], for vitamin D intake from supplements 1.09 [0.99-1.20]).

CONCLUSIONS/INTERPRETATION

Maternal intake of vitamin D either from food or supplements during pregnancy is not associated with advanced beta cell autoimmunity/type 1 diabetes or with type 1 diabetes alone in Finnish offspring carrying increased genetic susceptibility to type 1 diabetes.

Low levels of vitamin D in North Indian children with newly diagnosed type 1 diabetes

BACKGROUND

To find out whether vitamin D levels are lower in children with newly diagnosed type 1 diabetes (T1D) as compared to non-diabetic subjects.

METHODS

Plasma levels of vitamin D (25-OHD) were measured by high performance liquid chromatography (HPLC) in 50 children aged between 6 and 12 yr within a week of diagnosis of T1D, and in 50 healthy children.

RESULTS

The mean levels of vitamin D were significantly lower in patients as compared to their controls [20.02 +/- 10.63 ng/mL (50.05 +/- 26.57 mmol/L) vs. 26.16 +/- 12.28 ng/mL (65.4 +/- 30.7 mmol/L), p-value 0.009]. Twenty-nine (58%) children in the study group were vitamin D deficient (25-OHD level < 20 ng/mL or < 50 mmol/L) as compared to only 16 (32%) in the control group. Overall, 43 (86%) diabetic and 38 (76%) healthy children were either vitamin D deficient or insufficient.

CONCLUSION

These results suggest that vitamin D levels are low at the onset of T1D, and they strongly support the need for further clinical studies to prospectively evaluate the effect of vitamin D supplementation on T1D rates in this patient population.

Developmental vitamin D deficiency causes abnormal brain development

There is now clear evidence that vitamin D is involved in brain development. Our group is interested in environmental factors that shape brain development and how this may be relevant to neuropsychiatric diseases including schizophrenia. The origins of schizophrenia are considered developmental. We hypothesised that developmental vitamin D (DVD) deficiency may be the plausible neurobiological explanation for several important epidemiological correlates of schizophrenia namely: (1) the excess winter/spring birth rate, (2) increased incidence of the disease in 2nd generation Afro-Caribbean migrants and (3) increased urban birth rate. Moreover we have published two pieces of direct epidemiological support for this hypothesis in patients. In order to establish the "Biological Plausibility" of this hypothesis we have developed an animal model to study the effect of DVD deficiency on brain development. We do this by removing vitamin D from the diet of female rats prior to breeding. At birth we return all dams to a vitamin D containing diet. Using this procedure we impose a transient, gestational vitamin D deficiency, while maintaining normal calcium levels throughout. The brains of offspring from DVD-deficient dams are characterised by (1) a mild distortion in brain shape, (2) increased lateral ventricle volumes, (3) reduced differentiation and (4) diminished expression of neurotrophic factors. As adults, the alterations in ventricular volume persist and alterations in brain gene and protein expression emerge. Adult DVD-deficient rats also display behavioural sensitivity to agents that induce psychosis (the NMDA antagonist MK-801) and have impairments in attentional processing. In this review we summarise the literature addressing the function of vitamin D on neuronal and non-neuronal cells as well as in vivo results from DVD-deficient animals. Our conclusions from these data are that vitamin D is a plausible biological risk factor for neuropsychiatric disorders and that vitamin D acts as a neurosteroid with direct effects on brain development.

Vitamin D and non-Hodgkin lymphoma risk in adults: a review

Animal and human studies support a protective effect of vitamin D sufficiency related to malignancy by uncovering paracrine and autocrine effects of extra-renal 25-hydroxyvitamin D (25(OH)D) activation including regulation of cell cycle proliferation, apoptosis induction, and increased cell differentiation signaling. Recent epidemiologic studies demonstrate a reduction in non-Hodgkin lymphoma (NHL) risk with increased sunlight exposure. As sunlight is a major vitamin D source, it has been suggested that vitamin D status may mediate this observed association. This review provides a comprehensive discussion of the current epidemiologic evidence with regard to the investigation of an association between vitamin D status and NHL risk.

Vitamin D: emerging new roles in insulin sensitivity

The growing incidence of prediabetes and clinical type 2 diabetes, in part characterised by insulin resistance, is a critical health problem with consequent devastating personal and health-care costs. Vitamin D status, assessed by serum 25-hydroxyvitamin D levels, is inversely associated with diabetes in epidemiological studies. Several clinical intervention studies also support that vitamin D, or its active metabolite 1,25-dihydroxyvitamin D (1,25(OH)2D), improves insulin sensitivity, even in subjects with glucose metabolism parameters classified within normal ranges. The mechanisms proposed which may underlie this effect include potential relationships with improvements in lean mass, regulation of insulin release, altered insulin receptor expression and specific effects on insulin action. These actions may be mediated by systemic or local production of 1,25(OH)2D or by suppression of parathyroid hormone, which may function to negatively affect insulin sensitivity. Thus, substantial evidence supports a relationship between vitamin D status and insulin sensitivity; however, the underlying mechanisms require further exploration.

Long-term trends in the incidence of type 1 diabetes in Denmark: the seasonal variation changes over time

There is a worldwide increase of type 1 diabetes mellitus (T1DM). In 1996, the Danish population-based registry was initiated including all newly diagnosed children aged 0-15 yr. This is the report of incidence and seasonal variation for the first 10 yr of the registry. The data was analyzed using Poisson's regression analysis. A total of 2166 children with diabetes were diagnosed before the age of 15 yr between 1996 and 2005. In this period, the annual increase in childhood T1DM was 3.43% (95% confidence interval: 1.91-4.97), which was unaffected by age and gender. Seasonal variation in incidence rates varied by year but not by age and gender. In conclusion, there is a steep increase in incidence of childhood T1DM in Denmark; the increase is comparable with the increase seen in other European countries. There is a significant seasonal variation that changes on a year-to-year basis. The observed variations in cadence rates may be associated with viral epidemics, sunshine exposure, or vitamin D levels and suggest further exploration of these relations.

The association between ketoacidosis and 25(OH)-vitamin D levels at presentation in children with type 1 diabetes mellitus

BACKGROUND

There is considerable evidence supporting the role of vitamin D deficiency in the pathogenesis of type 1 diabetes mellitus (T1DM). Vitamin D deficiency is also associated with impairment of insulin synthesis and secretion. There have been no formal studies looking at the relationship between 25(OH)-vitamin D(3) and the severity of diabetic ketoacidosis (DKA) in children at presentation with T1DM.

OBJECTIVE

To determine the relationship between measured 25(OH)-vitamin D(3) levels and the degree of acidosis in children at diagnosis with T1DM.

SUBJECTS

Children presenting with new-onset T1DM at a tertiary children's hospital.

METHODS

25(OH)-vitamin D(3) and bicarbonate levels were measured in children at presentation with newly diagnosed T1DM. Those with suboptimal 25(OH)-vitamin D(3) levels (<50 nmol/L) had repeat measurements performed without interim vitamin D supplementation.

RESULTS

Fourteen of the 64 children had low 25(OH)-vitamin D(3) levels at presentation, and 12 of these had low bicarbonate levels (<18 mmol/L) (p = 0.001). Bicarbonate explained 20% of the variation in vitamin D level at presentation (partial r(2) = 0.20, p < 0.001) and ethnic background a further 10% (partial r(2) = 0.10, p = 0.002). The levels of 25(OH)-vitamin D(3) increased in 10 of the 11 children with resolution of the acidosis.

CONCLUSIONS

Acid-base status should be considered when interpreting 25(OH)-vitamin D(3) levels in patients with recently diagnosed T1DM. Acidosis may alter vitamin D metabolism, or alternatively, low vitamin D may contribute to a child's risk of presenting with DKA.

Altered endocrine and autocrine metabolism of vitamin D in a mouse model of gastrointestinal inflammation

The active form of vitamin D, 1,25-dihydroxyvitamin D3, [1,25(OH)2D3] has potent actions on innate and adaptive immunity. Although endocrine synthesis of 1,25(OH)2D3 takes place in the kidney, the enzyme that catalyzes this, 25-hydroxyvitamin D-1alpha-hydroxylase (CYP27b1 in humans, Cyp27b1 in mice), is expressed at many extra-renal sites including the colon. We have shown previously that colonic expression of CYP27b1 may act to protect against the onset of colitis. To investigate this further, we firstly characterized changes in Cyp27b1 expression in a mouse model of colitis. Mice treated with dextran sodium sulfate (DSS) showed weight loss, histological evidence of colitis, and increased expression of inflammatory cytokines. This was associated with decreased renal expression of Cyp27b1 (5-fold, P=0.013) and lower serum 1,25(OH)2D3 (51.8+/-5.9 pg/nl vs. 65.1+/-1.6 in controls, P<0.001). However, expression of CYP27b1 was increased in the proximal colon of DSS mice (4-fold compared with controls, P<0.001). Further studies were carried out using Cyp27b1 null (-/-) mice. Compared with+/-controls the Cyp27b1-/-mice showed increased weight loss (4.9% vs. 22.8%, P<0.001) and colitis. This was associated with raised IL-1 in the distal colon and IL-17 in the proximal and distal colon. Conversely, DSS-treated Cyp27b1-/-mice exhibited lower IL-10 in the proximal colon and toll-like receptors 2 and 4 in the distal colon. These data indicate that both local and endocrine synthesis of 1,25(OH)2D3 affect colitis in DSS-treated mice. Lack of Cyp27b1 exacerbates disease in this model, suggesting that similar effects may occur with vitamin D deficiency.

Vitamin D: a growing perspective

Vitamin D deficiency has been widely reported in all age groups in recent years. Rickets has never been eradicated in developed countries, and it most commonly affects children from recent immigrant groups. There is much evidence that current vitamin D guidelines for the neonatal period, 5-10 microg (200-400 IU)/day, prevent rickets at the typical calcium intakes in developed countries. The annual incidence of vitamin D-deficiency rickets in developed countries ranges between 2.9 and 7.5 cases per 100,000 children. The prevalence of vitamin D deficiency in mothers and their neonates is remarkable, and the results of one study suggest that third-trimester 25-hydroxyvitamin D (25(OH)D) is associated with fetal bone mineral accrual that may affect prepubertal bone mass accumulation. Beyond infancy, the evidence indicates that 5 microg (200 IU)/day of vitamin D has little effect on vitamin D status as measured by the serum 25(OH)D concentration. Two randomized clinical trials show that higher vitamin D intake improves one-year gain in bone density in adolescent girls. The functions of vitamin D extend beyond bone to include immune system regulation and anti-proliferative effects on cells. Early life vitamin D inadequacy is implicated in the risk of bone disease, autoimmune disease, and certain cancers later in life; however, long-term interventional studies do not exist to validate the widespread implementation of greater vitamin D consumption. Here we review the available data concerning vitamin D status and health effects of vitamin D in pregnancy through to and including adolescence.

The paradoxical effects of vitamin D on type 1 mediated immunity

Low vitamin D status is associated with an increased risk of Th1 mediated autoimmune diseases like inflammatory bowel disease. 1,25(OH)(2)D(3) treatments have been shown to suppress Th1 mediated immunity and protect animals from experimental autoimmunity. Th1 mediated immunity is important for clearance of a number of different infectious diseases. For tuberculosis 1,25(OH)(2)D(3) treatment is associated with decreased Th1 mediated immunity but increased bactericidal activity. Systemic candidiasis is unaffected by 1,25(OH)(2)D(3) treatment. The seemingly paradoxical effects of 1,25(OH)(2)D(3) and vitamin D on Th1 mediated autoimmunity versus infectious immunity point to a broad array of vitamin D targets in the immune system. The interplay of these vitamin D targets and their impact on the host-immune response then dictate the outcome.

Comparative therapeutic effects of orally administered 1,25-dihydroxyvitamin D(3) and 1alpha-hydroxyvitamin D(3) on type-1 diabetes in non-obese diabetic mice fed a normal-calcaemic diet

Frequent injections of the hormonal form of vitamin D(3), 1,25 dihydroxyvitamin D(3) (1,25D3) reportedly inhibits autoimmune type 1 diabetes (T1D) in non-obese diabetic (NOD) mice by correcting some of the abnormalities in antigen-presenting cells which contribute the development of pathogenic T cell responses. This route of administration greatly elevates the levels of these compounds in the bloodstream for hours after treatment, which requires mice to be fed diets formulated to contain much reduced levels of Ca to avoid the toxic effects of hypercalcaemia. In the current work, we demonstrate that feeding 1,25D3 or its synthetic precursor, 1alpha(OH) vitamin D(3) (1alphaD3), as part of a T1D supportive chow diet containing normal levels of Ca, is an effective means of reducing the incidence of disease in NOD mice, but the doses required for protection elicited hypercalcaemia. However, T1D protection elicited by D3 analogue feeding appears, at least partially, to have an immunological basis, as splenic T cells from treated mice had a decreased capacity to adoptively transfer disease. Protection is associated with an increased proportion of T cells with CD4+ forkhead box P3+ regulatory phenotype within the islet infiltrate of treated animals. The 1alphaD3 precursor is converted rapidly to the active 1,25D3 isoform in vivo. However, feeding the 1alphaD3 analogue elicited stronger T1D protection than the 1,25D3 compound, but also induced more severe hypercalcaemia. In future, the dietary supplementation of novel low-calcaemic D3 analogues may enable their continuous delivery at levels that inhibit T1D development in susceptible humans consuming normal levels of Ca.

Monocytes from type 2 diabetic patients have a pro-inflammatory profile. 1,25-Dihydroxyvitamin D(3) works as anti-inflammatory

The exact factors contributing to the pathogenesis of type 2 diabetes remain elusive. Lately, it was suggested that inflammation and activation of the innate immune system could be linked to type 2 diabetes pathogenesis and also to the development of common diabetic complications, mainly atherosclerosis. The aim of this study was to investigate the role of monocytes in this sub-clinical inflammatory state and test 1,25-dihydroxyvitamin D(3), the active form of Vitamin D, as an anti-inflammatory agent. For this purpose, monocytes from type 2 diabetic patients were compared to monocytes from healthy controls and type 1 diabetic patients. The expression profile of inflammatory markers in freshly isolated and immune-stimulated monocytes was measured by quantitative real-time RT-PCR. Type 2 diabetic patients showed significantly higher expression levels of TNF-alpha, IL-6, IL-1, IL-8, COX-2, ICAM-1 and B7-1 compared to controls and type 1 diabetic patients. 1,25-Dihydroxyvitamin D(3) was able to down-regulate the expression of TNF-alpha, IL-6, IL-1, and IL-8, confirming its immunomodulatory properties. From these data we concluded that monocytes from type 2 diabetic patients have a pro-inflammatory profile. In addition, 1,25-dihydroxyvitamin D(3) was able to modulate inflammation in these monocytes.