Severe deficiency of 25-hydroxyvitamin D₃ (25-OH-D₃) is associated with high disease activity of rheumatoid arthritis

Association of 25-Hydroxy Vitamin D with IL-17 Inflammatory Cytokines, and Osteoporosis in patients with Rheumatoid Arthritis in Kurdish nation / Iraq

Introduction:

Rheumatoid arthritis (RA) is a long-term autoimmune disorder that primarily affects joints. Lower Vitamin D (Vit. D) levels correlate with more severe clinical manifestations in RA and other rheumatic diseases. IL-17A promotes inflammation by inducing various proinflammatory cytokines and chemokines. In this study, we evaluated the association between Vitamin. D and IL-17 in osteoporosis in Rheumatoid Arthritis in Kurdish nation / Iraq.

Objective:

Blood samples from rheumatoid arthritis (RA) patients were used to measure the levels of the inflammatory cytokine IL-17 and the Vit. D precursor 25(OH)D and bone loss in patients with RA in this study.

Methods:

In this study, 40 healthy controls were included in the research, which comprised 100 new cases of RA. ELISA was used to measure the level of serum 25(OH)D and IL-17. Moreover, DXA was used to assess average bone mineral density (BMD).

Results:

We discovered no difference between the two groups in terms of age or gender. This means that compared to the control group, the 25(OH)D serum levels in the RA group were lower (P 0.01; 16.85+8.7 nmol/l vs. 39.95 (-+9.8)). IL-17 serum levels were highly and negatively associated with 25(OH)D levels in arthritic patients. A comparison of 25(OH)D levels in patients with osteoporosis and osteopenia and those with BMD was also performed.

Conclusion:

Bone loss and IL-17 have been associated with reduced Vit. D levels in patients with rheumatoid arthritis; a lack of Vit. D may have a role in developing the disease, according to the data presented in this study.

Association Between Rheumatoid Arthritis and Serum Vitamin D Levels

Introduction

Vitamin D is responsible for regulating innate and adaptive immune responses and for boosting the immune system; hence, a decline in its levels results in autoimmunity. Current studies have linked the deficiency of vitamin D to different autoimmune diseases, including rheumatoid arthritis (RA). In this study, we will determine the association between vitamin D level and RA.

Methods

This is a case-control study, conducted in a tertiary care hospital in Pakistan from January 2021 to May 2021. Three hundred patients with a confirmed recent diagnosis of RA were enrolled as the study group. Another 300 participants without RA, matched for age and gender, were enrolled in the study as a control group. RA was diagnosed on the basis of clinical symptoms, radiological features on X-ray, and anti-citrullinated protein levels of more than 20 u/mL.

Results

The mean vitamin D level in participants with RA was significantly lower than in the placebo group (30.18 ± 6.27 vs. 38.29 ± 7.98; p-value: <0.0001). The mean vitamin D level in participants with positive RF patients was significantly lower compared to rheumatoid factor (RF)-negative RA patients (29.21 ± 5.16 vs. 32.26 ± 7.02; p-value: <0.0001). There were more participants with hypovitaminosis D in RF-positive participants as compared to RF negative (88.6% vs. 44.3%; p-value: 0.00001).

Conclusion

There is a high prevalence of vitamin D deficiency in patients with RA and there is a link with disease severity. Therefore, a high index of suspicion is required while evaluating the at-risk patients, especially women, with complaints of vitamin D deficiency. Vitamin D supplementation may be needed for the prevention or avoidance of the progression of the disease.

Genetic and expression deregulation of immunoregulatory genes in rheumatoid arthritis

Rheumatoid arthritis (RA) is one of the most common autoimmune diseases globally, and is an important public health concern, associating with early death and systemic complications. Although key development in RA treatment has already been made still RA affected individuals face comorbidity and disability. Therefore, there is a need to discover new risk factors in helping early diagnosis and treatment of RA. The present study is designed to assess the variations of Vitamin D receptor (VDR) and interleukin -6 (IL-6) in RA patients. Polymorphisms of said genes were calculated in 300 RA patients and 300 controls, using Tetra-ARMS polymerase chain reaction. Secondly, expression levels of selected genes were checked using the quantitative PCR (qPCR) and obtained results were evaluated using a different statistical test. Logistic regression analysis showed that frequency of mutant allele of VDR gene polymorphisms (rs11168268, OR = 4.84; 95% CI = 2.94-7.97; p = 0.0001; rs2248098, OR = 1.65; 95% CI = 1.07-2.54; p = 0.02) and IL-6 gene polymorphisms (rs184229712, OR = 2.47; 95% CI = 1.56-3.92, p = 0.0001; rs36215814, OR = 2.14; 95% CI = 1.30-3.53; p = 0.002) was observed significantly higher in RA patients vs controls. Expression analysis showed the significant upregulation of IL-6 (p < 0.0001) and downregulation of VDR gene (p < 0.0001) in RA cases vs controls. ROC curve analysis showed that downregulation of IL-6 (AUC = 0.86, p < 0.001) and upregulation of VDR (AUC = 0.77, p < 0.001) was act as the good diagnostic marker for detection/diagnosis of arthritis. In conclusions, data from the present study showed the significant involvement of VDR and IL-6 gene variations in RA pathogenesis.

The Role of Vitamin D in Combination Treatment for Patients With Rheumatoid Arthritis

Background: The aim of this study is to evaluate the clinical efficacy of vitamin D (VitD) supplementation in terms of response to treatment and improvement of disease activity in rheumatoid arthritis (RA). Methods: This study analyzed 1180 RA patients' records treated at Mianyang Central Hospital from February 2015 to July 2019. The patients were allocated into VitD group and control group based on their medical regimens. The outcome measures were primary efficacy, defined as treatment response-based EULAR response criteria in RA, and secondary efficacy, defined as improvement in disease activity indicators. Safety was evaluated according to the incidence of all-cause infections. Results: At month 6, the primary efficacy revealed that there were 22.8% good responders and 19.0% moderate responders in the VitD group, and 22.3% good responders and 22.3% moderate responders in the control group; there were no differences between the two groups (p = 0.754). The similar primary efficacy outcomes were observed at months 3, 12, and >12. The secondary efficacy indicated that there were no differences in most indexes between the two groups at months 1, 3, 6, 12, and >12. The subgroups (based on baseline DAS28 (CRP), glucocorticoids use and disease duration) analysis results suggested that VitD group didn't have the advantage for treating RA. The incidence of infections was similar in the two groups. Conclusion: VitD supplementation did not provide additional benefit for anti-rheumatic treatment. These data supported the need for prospective, randomized, controlled trials to evaluate the role of VitD supplementation in treating RA.

Vitamin D Deficiency and Rheumatoid Arthritis: Epidemiological, Immunological, Clinical and Therapeutic Aspects

Background/Aim:

Vitamin D displays an immunologic effect which can modulate function of Th17-related cytokines and thereby prevent perpetuation of inflammation in chronic disorders like rheumatoid arthritis (RA). This review aims to conduct a literature review to provide a summary of recent studies addressing the relationship between vitamin D deficiency and RA based on epidemiological, immunological and therapeutic aspects.

Methods:

PubMed, Scopus and Google scholar were searched for relevant papers published between 2000–2018.

Results:

Low intake of vitamin D increases the risk of incident RA, and vitamin D deficiency has been shown to be inversely associated with RA activity in most of these studies. However, characteristics of RA and serum vitamin D status differ across the studies. The results of studies on the effect of supplemental vitamin D in RA vary, from no efficacy to significant improvement in disease activity, as well as quality of life. This should be attributed to variations in dosage of vitamin D, duration of treatment, baseline serum vitamin D in RA patients and characteristics of RA across diverse studies.

Conclusion:

Current data indicate a therapeutic potential for vitamin D in RA. However, further studies are needed to identify an optimal and effective dosage, duration of treatment and patients who will get the best benefit from the treatment.

Vitamin D, Autoimmune Disease and Rheumatoid Arthritis

Vitamin D has been reported to influence physiological systems that extend far beyond its established functions in calcium and bone homeostasis. Prominent amongst these are the potent immunomodulatory effects of the active form of vitamin D, 1,25-dihydroxyvitamin D3 (1,25-(OH)2D3). The nuclear vitamin D receptor (VDR) for 1,25-(OH)2D3 is expressed by many cells within the immune system and resulting effects include modulation of T cell phenotype to suppress pro-inflammatory Th1 and Th17 CD4+ T cells and promote tolerogenic regulatory T cells. In addition, antigen-presenting cells have been shown to express the enzyme 1α-hydroxylase that converts precursor 25-hydroxyvitamin D3 (25-OHD3) to 1,25-(OH)2D3, so that immune microenvironments are able to both activate and respond to vitamin D. As a consequence of this local, intracrine, system, immune responses may vary according to the availability of 25-OHD3, and vitamin D deficiency has been linked to various autoimmune disorders including rheumatoid arthritis (RA). The aim of this review is to explore the immune activities of vitamin D that impact autoimmune disease, with specific reference to RA. As well as outlining the mechanisms linking vitamin D with autoimmune disease, the review will also describe the different studies that have linked vitamin D status to RA, and the current supplementation studies that have explored the potential benefits of vitamin D for prevention or treatment of RA. The overall aim of the review is to provide a fresh perspective on the potential role of vitamin D in RA pathogenesis and treatment.

Vitamin D as a Principal Factor in Mediating Rheumatoid Arthritis-Derived Immune Response

Rheumatoid arthritis (RA) is a systemic multifactorial autoimmune disorder. The interactions between diverse environmental and genetic factors lead to the onset of this complex autoimmune disorder. Serum levels of vitamin D (VD) are involved in the regulation of various immune responses. Vitamin D is a key signaling molecule in the human body that maintains calcium as well as phosphate homeostasis. It also regulates the functions of the immune system and, thus, can play a substantial role in the etiology of various autoimmune disorders, including RA. Low serum VD levels have been found to be associated with a higher risk of RA, although this finding has not been replicated consistently. The molecular mechanisms by which VD influences autoimmunity need to be further explored to understand how variation in plasma VD levels could affect the pathogenesis of RA. This mini-review focuses on the influence of VD and its serum levels on RA susceptibility, RA-associated complexities, treatment, and transcriptome products of key proinflammatory cytokines, along with other cytokines that are key regulators of inflammation in rheumatoid joints.

1,25(OH)2D3 promotes chondrocyte apoptosis and restores physical function in rheumatoid arthritis through the NF-κB signal pathway

We explored the modulatory effect of 1,25(OH)₂D₃ on chondrocytes and physical function in rats with RA and its mechanism underlying the regulation of NF-κB signal pathway. RA patients and healthy volunteers were selected. Sprague-Dawley (SD) rats were used to establish RA models. The paw volume of rats was estimated. Chondrocytes were isolated from RA rats. The protein levels in both cartilage tissues and chondrocytes were determined using western blotting. Apoptosis was evaluated using TUNEL assay. Serum levels of IL-1β, IL-6, IL-10 and IL-17 were measured by enzyme-linked immunosorbent assay (ELISA). Serum levels of 1,25(OH)₂D₃ were lower in RA patients than in healthy volunteers. Rats in the RA + VD₃ group were lighter than those in normal and PBS groups, with an increased paw volume, severer joint swelling, higher expression levels of p-IκBα, p-p65, IL-1β, IL-6, and IL-17, and lower expression level of IL-10, while those in RA and RA + VD₃ + NF-κB group differed more significantly. In addition, by comparing RA rats and RA + NF-κB rats, we found that TNF-α stimulation exacerbated RA, increased expression levels of p-IκBα, p-p65, IL-1β, IL-6, and IL-17, and decreased the expression level of IL-10. Compared with RA chondrocytes, chondrocytes from RA + VD₃ rats exhibited lower expression levels of p-IκBα and p-p65, and had more apoptotic cells, while those from RA + NF-κB rats showed an opposite trend. Taken together, 1,25(OH)₂D₃ accelerates chondrocyte apoptosis and improve physical function in rats with RA by the inhibition of NF-κB signal pathway.

Evaluation of Vitamin D Status in Rheumatoid Arthritis and Its Association with Disease Activity across 15 Countries: "The COMORA Study"

The aims of this study are to evaluate vitamin D status in 1413 RA patients of COMORA study from 15 countries and to analyze relationship between patients' RA characteristics and low levels of vitamin D. All demographic, clinical, and biological data and RA comorbidities were completed. The results showed that the average of vitamin D serum dosage was 27.3 ng/mL ± 15.1 [0.1–151]. Status of vitamin D was insufficient in 54.6% and deficient in 8.5% of patients. 43% of RA patients were supplemented with vitamin D and absence of supplementation on vitamin D was related to higher prevalence of vitamin D deficiency (p < 0.001). Finally, our study shows that the status of low levels of vitamin D is common in RA in different countries and under different latitudes. Absence of supplementation on vitamin D was related to higher prevalence of vitamin D deficiency. Low levels of vitamin D were associated with patients characteristics (age, BMI, and educational level), RA (disease activity and corticosteroid dosage), and comorbidities (lung disease and osteoporosis therapy). This suggests the need for a particular therapeutic strategy to improve vitamin D status in RA patients.

Vitamin D deficiency as a risk factor for the development of autoantibodies in patients with ASIA and silicone breast implants: a cohort study and review of the literature

The development of autoimmunity and/or autoimmune diseases is multifactorial. Vitamin D is one of the factors that might play a role. We postulated that both the presence of adjuvants and insufficient levels of vitamin D may result in the development of autoimmunity in patients with autoimmune/inflammatory syndrome induced by adjuvants (ASIA) in relation to silicone implant incompatibility. We measured vitamin D levels in 135 patients with ASIA in relation to silicone implant incompatibility and related findings to the presence of autoantibodies that are commonly used to diagnose systemic autoimmune diseases. Furthermore, we systematically reviewed the literature regarding vitamin D deficiency as a risk factor for the development of autoantibodies. Vitamin D measurements were available for analysis in 131 of 135 patients with ASIA in relation to SIIS. Twenty-three patients (18%) tested positive for autoantibodies, from which 18 patients (78%) had either a vitamin D deficiency or insufficiency (median vitamin D level 60.5 mmol/L), whereas five patients (22%) had sufficient vitamin D levels. The risk to develop autoantibodies was significantly increased in vitamin D deficient and/or insufficient patients [RR 3.14; 95% CI, 1.24–7.95; p = 0.009]. Reviewed literature suggested an association between vitamin D levels and the presence and/or titer levels of autoantibodies in different autoimmune diseases. From our current study and from our review of the literature, we conclude that vitamin D deficiency is related to the presence of autoantibodies. Whether vitamin D supplementation results in a decrease of autoimmunity needs to be studied prospectively.

Vitamin D receptor polymorphisms and expression profile in rheumatoid arthritis Brazilian patients

Rheumatoid arthritis (RA) is an autoimmune disease characterized by chronic inflammation and important joint commitment, being the most common systemic autoimmune disease worldwide. RA displays important genetic background with a variety of genes contributing to the immune balance breakdown. Recent studies have demonstrated that vitamin D, through its receptor (VDR), is able to regulate the immune balance and suppress the autoimmunity process, being a potential target in autoimmune diseases. In the present genetic association study, we assessed 5 Tag single nucleotide polymorphisms (SNPs) (rs11168268, rs2248098, rs1540339, rs4760648 and rs3890733), which cover most of the VDR gene, in three different Brazilian populations (from Northeast, Southeast and South Brazil). We also evaluated the VDR expression profile in whole blood and monocytes from RA patients. For genotyping study, 428 RA patients and 616 healthy controls were genotyped with fluorogenic allele specific probes on an ABI7500 platform. For gene expression study, VDR mRNA levels of 15 RA patients and 26 healthy individuals were assessed by RT-PCR. Our results showed that SNPs rs4760648 and rs3890733 are associated to RA susceptibility (p value = 0.0026, OR 1.31 and p value = 0.0091, OR 1.28 with statistical power = 0.999 and 0.993, respectively). Regarding RA clinical features, the studied SNPs did not show significant associations. The gene expression assays showed that VDR mRNA levels were down regulated in both whole blood (-3.3 fold) and monocytes (-3.2 fold) of RA patients when compared to healthy controls. Our results, the first reported for distinct Brazilian populations, support a role of the VDR gene in the susceptibility to RA.

Vitamin D status and its association with quality of life, physical activity, and disease activity in rheumatoid arthritis patients

BACKGROUND

Vitamin D deficiency is common in rheumatoid arthritis (RA) and may be related to disease activity. Population-based studies have shown the influence of vitamin D deficiency on quality of life (QoL), but it was not investigated in RA patients.

OBJECTIVES

The aim of the study was to determine possible relationship between vitamin D deficiency, QoL, physical activity (PA), and disease activity in RA.

METHODS

In 97 consecutive RA patients without vitamin D supplementation (86 women and 11 men, aged 59.4 ± 12 years), serum 25-hydroxycholecalciferol (25(OH)D), calcium, phosphorus, and parathyroid hormone were measured. The patients completed Short Form 36 (SF-36), Beck Depression Inventory, and Health Assessment Questionnaire, assessed the intensity of pain, fatigue, and PA. Disease Activity Score in 28 Joints was used to assess disease activity. A comparison control group consisted of 28 osteoarthritis patients (25 women and 3 men aged 56.2 ± 15 years).

RESULTS

Vitamin D deficiency was detected in 76.3% of RA and in 78.6% of osteoarthritis patients (P = 0.75). There was a negative correlation between 25(OH)D serum concentration and Disease Activity Score in 28 Joints in patients with active arthritis. There was a positive correlation between serum 25(OH)D and the level of PA and most aspects of SF-36, and negative correlation between serum 25(OH)D and Health Assessment Questionnaire and Beck Depression Inventory in patients with disease duration of 1 year or longer. After inclusion of PA into multivariable analysis, only the correlations between 25(OH)D and SF-36 mental subscale (MCS) and pain remained significant.

CONCLUSIONS

Vitamin D deficiency is highly prevalent in RA patients and is associated with higher disease activity and worse QoL indices. Regular PA correlates with higher vitamin D titers and better QoL in RA. Further studies are needed to explain possible influence of vitamin D on RA activity.

Vitamin D in rheumatoid arthritis-towards clinical application

In addition to its well-documented involvement in mineral homeostasis, vitamin D seems to have broad effects on human health that go beyond the skeletal system. Prominent among these so-called nonclassical effects of vitamin D are its immunomodulatory properties. In vitro studies have shown anti-inflammatory effects of 1,25-dihydroxyvitamin D (1,25(OH)2D), the active form of vitamin D. In addition, epidemiological analysis of patients with established inflammatory disease identified associations between vitamin D deficiency (low serum concentrations of inactive 25-hydroxyvitamin D, abbreviated to 25(OH)D) and inflammatory conditions, including rheumatoid arthritis (RA). The association of vitamin D deficiency with RA severity supports the hypothesis of a role for vitamin D in the initiation or progression of the disease, or possibly both. However, whether 25(OH)D status is a cause or consequence of RA is still incompletely understood and requires further analysis in prospective vitamin D supplementation trials. The characterization of factors that promote the transition from preclinical to clinical phases of RA has become a major focus of research, with the aim to facilitate earlier diagnosis and treatment, and improve therapeutic outcomes. In this Review, we aim to describe the current knowledge of vitamin D and the immune system specifically in RA, and discuss the potential benefits that vitamin D might have on slowing RA progression.

Association between Serum 25-Hydroxyvitamin D Level and Rheumatoid Arthritis

The objective of this study is to examine and evaluate whether serum 25(OH)D is associated with disease activity in patients with rheumatoid arthritis (RA). Our results suggested that serum 25(OH)D in RA groups has significant lower level (35.99 ± 12.59 nmol/L) than that in the normal groups (54.35 ± 8.20 nmol/L, P < 0.05). Based on the DAS28, patients with RA were divided into four subgroups, and no differences were found in the four groups (P > 0.05). The 25(OH)D levels in complete remission, low disease activity, middle disease activity, and high disease activity group were 32.86 ± 12.26, 33.97 ± 13.28, 38.41 ± 10.64, and 38.94 ± 13.35 nmol/L, respectively. Based on the serum 25(OH)D levels, patients with RA were divided into inadequate group and normal group, and there were no significant differences in baseline characteristics and disease activity in the two groups. Our results showed that serum 25(OH)D levels in the inadequate group are significantly lower than those in the normal group. However, no correlations were found between 25(OH)D levels and disease activity among 116 patients with RA. The present findings will help to understand the association between 25(OH)D and disease activity of RA.

Vitamin D as an Immunomodulator: Risks with Deficiencies and Benefits of Supplementation

Vitamin D refers to a class of fat-soluble secosteroids often associated with their role in absorption and metabolism of minerals such as calcium and phosphate. In recent years, our understanding of vitamin D has expanded to include its role in modulating the immune system. Of particular focus are the effects of vitamin D deficiency and supplementation on patients suffering from disorders due to dysregulation of the immune system. In patients with multiple sclerosis, rheumatoid arthritis, and inflammatory bowel disease, deficiencies in vitamin D have been associated with an increased risk of disease activity. In this review, we will look at the current state of research in regards to the relationship between vitamin D and immune-dysregulation. We will focus on both the risks associated with vitamin D deficiency as well as the benefits of vitamin D supplementation.

Vitamin D and psoriasis pathology in the Mediterranean region, Valencia (Spain)

Vitamin D has important immunomodulatory effects on psoriasis in the Mediterranean region. To measure vitamin D intake in subjects with and without psoriasis, and to find an association with relevant clinical features, a case-control study was performed using cases (n = 50, 50% participation rate) clinically diagnosed with psoriasis and 200 healthy subjects (39.5% participation rate), leaving a final sample of 104 people. A survey was conducted using a food frequency questionnaire and clinical histories. Cases and controls were compared using univariate and multivariate analyses. We observed insufficient intake of cholecalciferol (vitamin D3) or ergocalciferol (vitamin D2) for both cases and controls. Patients with psoriasis were at greater risk of associated pathologies: dyslipidaemia (OR: 3.6, 95% CI: 0.8–15.2); metabolic syndrome (OR: 3.3, 95% CI: 0.2–53.9); hypertension (OR: 1.7, 95% CI: 0.4–7.2). Insufficient vitamin D intake in both psoriasis patients and controls in the Mediterranean population, and cardiovascular comorbility is more frequent in patients with psoriasis.

25-Hydroxy vitamin D and its relationship with clinical and laboratory parameters in patients with rheumatoid arthritis

The objective of this study is to evaluate the prevalence of vitamin D insufficiency in patients with rheumatoid arthritis (RA) and its association with disease activity, severity and physical disability. We included patients with rheumatoid arthritis followed in Rheumatology Department of Hassan II University Hospital, Fez, Morocco. Patients suffering from liver and kidney insufficiency and those who had received vitamin D in the previous 12 months have been excluded. Statistical analysis was done using SPSS v 18. A bivariate analysis and logistic regression were used to identify factors associated with vitamin D deficiency. One hundred seventy patients were included with a mean age of 50 ± 12.1 [17-83] years, and a female predominance (88.1%). All of our patients had hypovitaminosis D. The prevalence of 25(OH)-D insufficiency and deficiency was 64.5 and 35.5% successively. In unadjusted analysis, vitamin D concentration was inversely associated with pain visual analog scale VAS score (p < 0.001), asthenia VAS (p < 0.001), morning stiffness (p = 0.03), number of tender joints (p = 0.004), number of swollen joints (p < 0.001), inflammatory markers (p = 0,012), Disease Activity Score (p = 0.009), physical disability using Health Assessment Questionnaire (HAQ) (p = 0.001), and severity of the disease (p < 0.001). After logistic regression persisted association with female sex (OR = 4.3, CI = [0.94 to 20.976], p = 0.05), asthenia VAS (OR = 1.029, CI = [1.011 to 1.046], p = 0.001), and with the severity of the disease (OR = 2.910, CI = [1.314-6.441], p = 0.008). The vitamin D deficiency is common in our patients with RA. This deficiency is associated with female sex, severe asthenia, and the severity of the disease.

Associations between serum 25-hydroxyvitamin D and disease activity, inflammatory cytokines and bone loss in patients with rheumatoid arthritis

OBJECTIVE

The aim of this study was to describe the associations between serum levels of 25-hydroxyvitamin D [25(OH)D] and disease activity, inflammatory cytokines and bone loss/erosions in patients with RA.

METHODS

The study included 130 patients with RA and 80 healthy controls. Serum 25(OH)D, IL-17 and IL-23 levels were detected by ELISA. Radiographic bone erosion was assessed using the van der Heijde modified Sharp score and BMD was measured using DXA.

RESULTS

There were no significant differences in age, gender and BMI between the RA and control groups. Serum level of 25(OH)D was markedly lower in the RA group than in the control group [43.12 nmol/l (s.d. 15.59) vs 57.93 (15.95), P < 0.01]. In RA patients, 25(OH)D levels were significantly and negatively associated with clinical parameters of disease activity including swollen joint count, tender joint count, joint pain degree, morning stiffness time and HAQ score and laboratory measures including platelets and ESR after adjustment for gender, age and BMI. They were also negatively associated with serum levels of IL-17 and IL-23. While 25(OH)D levels were not associated with radiographic bone erosions of RA, they were significantly lower in those with osteopenia and osteoporosis than in those with normal BMD (P < 0.01).

CONCLUSION

25(OH)D levels were reduced in patients with RA and were negatively associated with disease activity, IL-17/IL-23 and bone loss in RA. These suggest that vitamin D deficiency may play a role in the aetiology of RA.

The role of lipid-activated nuclear receptors in shaping macrophage and dendritic cell function: From physiology to pathology

Nuclear receptors are ligand-activated transcription factors linking lipid signaling to the expression of the genome. There is increasing appreciation of the involvement of this receptor network in the metabolic programming of macrophages and dendritic cells (DCs), essential members of the innate immune system. In this review we focus on the role of retinoid X receptor, retinoic acid receptor, peroxisome proliferator-associated receptor γ, liver X receptor, and vitamin D receptor in shaping the immune and metabolic functions of macrophages and DCs. We also provide an overview of the contribution of macrophage- and DC-expressed nuclear receptors to various immunopathologic conditions, such as rheumatoid arthritis, inflammatory bowel disease, systemic lupus erythematosus, asthma, and some others. We suggest that systematic analyses of the roles of these receptors and their activating lipid ligands in immunopathologies combined with complementary and focused translational and clinical research will be crucial for the development of new therapies using the many molecules available to target nuclear receptors.

Vitamin D and glycemic control in diabetes mellitus type 2

OBJECTIVES

The extraskeletal effects of vitamin D have attracted considerable interest. Vitamin D deficiency appears to be related to the development of diabetes mellitus type 2 and the metabolic syndrome. Vitamin D may affect glucose homeostasis, vitamin D levels having been found to be inversely related to glycosylated hemoglobin levels in gestational diabetes mellitus. In addition, vitamin D appears to protect from the development of gestational diabetes mellitus. The aim was to study levels of 25-hydroxy vitamin D3 [25(OH)D3] and the relationship between 25(OH)D3 levels and glycemic control in patients with diabetes mellitus type 2.

METHODS

Glycosylated hemoglobin (HbA1c) and 25(OH)D3 levels were measured in a group of 120 diabetes mellitus type 2 patients. The same measurements were performed in a group of 120 control subjects of the same age and sex. 25(OH)D3 was measured by radioimmunoassay and glycosylated hemoglobin (HbA1c) was measured by high-performance liquid chromatography.

RESULTS

25(OH)D3 levels were lower in the diabetes mellitus type 2 patients than in the control group, being 19.26 ± 0.95 ng/ml and 25.49 ± 1.02 ng/ml, in the patient and control groups, respectively (p < 0.001, Student's t-test). 25(OH)D3 levels were found to be inversely associated with HbA1c levels in the diabetic patients (p = 0.008, r (2) = 0.058, linear regression). 25(OH)D3 levels were found to be inversely associated with HbA1c when the patient and control groups were analysed together (p < 0.001, r (2) = 0.086).

CONCLUSIONS

Vitamin D levels appeared to be lower in diabetes mellitus type 2 patients than in the control group, vitamin D levels being related to glycemic control in diabetes mellitus type 2. These findings may have therapeutic implications as cautious vitamin D supplementation may improve glycemic control in diabetes mellitus type 2.

Vitamin D for health: a global perspective

It is now generally accepted that vitamin D deficiency is a worldwide health problem that affects not only musculoskeletal health but also a wide range of acute and chronic diseases. However, there remains cynicism about the lack of randomized controlled trials to support the association studies regarding the nonskeletal health benefits of vitamin D. This review was obtained by searching English-language studies published up to April 1, 2013, in PubMed, MEDLINE, and the Cochrane Central Register of Controlled Trials (search terms: vitamin D and supplementation) and focuses on recent challenges regarding the definition of vitamin D deficiency and how to achieve optimal serum 25-hydroxyvitamin D concentrations from dietary sources, supplements, and sun exposure. The effect of vitamin D on fetal programming epigenetics and gene regulation could potentially explain why vitamin D has been reported to have such wide-ranging health benefits throughout life. There is potentially a great upside to increasing the vitamin D status of children and adults worldwide for improving musculoskeletal health and reducing the risk of chronic illnesses, including some cancers, autoimmune diseases, infectious diseases, type 2 diabetes mellitus, neurocognitive disorders, and mortality.

Enrichment of vitamin D response elements in RA-associated loci supports a role for vitamin D in the pathogenesis of RA

The aim of this study was to explore the role of vitamin D in rheumatoid arthritis (RA) pathogenesis by investigating the enrichment of vitamin D response elements (VDREs) in confirmed RA susceptibility loci and testing variants associated with vitamin D levels for association with RA. Bioinformatically, VDRE genomic positions were overlaid with non-HLA (human leukocyte antigen)-confirmed RA susceptibility regions. The number of VDREs at RA loci was compared to a randomly selected set of genomic loci to calculate an average relative risk (RR). Single-nucleotide polymorphisms (SNPs) in the DHCR7/NADSYN1 (nicotinamide adenine dinucleotide synthase 1) and CYP2R1 loci, previously associated with circulating vitamin D levels, were tested in UK RA cases (n=3870) and controls (n=8430). Significant enrichment of VDREs was seen at RA loci (P=9.23 × 10(-8)) when regions were defined either by gene (RR 5.50) or position (RR 5.86). SNPs in the DHCR7/NADSYN1 locus showed evidence of positive association with RA, rs4944076 (P=0.008, odds ratio (OR) 1.14, 95% confidence interval (CI) 1.03-1.24). The significant enrichment of VDREs at RA-associated loci and the modest association of variants in loci-controlling levels of circulating vitamin D supports the hypothesis that vitamin D has a role in the development of RA.