High-dose cholecalciferol supplementation significantly increases peripheral CD4⁺ Tregs in healthy adults without negatively affecting the frequency of other immune cells.

BACKGROUND: Regulatory T cells (Tregs) play a central role in the maintenance of self-tolerance. Animal and in vitro studies suggest that vitamin D is involved in reducing the risk of autoimmunity by modulating Tregs. METHODS: In a double-blind, placebo controlled study in 60 healthy volunteers, we assessed the effect of a 12-week high-dose oral cholecalciferol supplementation (140,000 IU/month) on the number and function of CD4(pos)CD25(high)FoxP3(pos)CD127(dim) Tregs. We also assessed the clinical safety of the supplementation and the effect on the frequency of other immune cells such as monocytes, dendritic cells, natural killer cells, natural killer T cells, B cells and subgroups of T cells. We also tested the in vitro effect of cholecalciferol on Tregs in human cell cultures. RESULTS: By using FACS analysis, ex vivo suppressive co-cultures and apoptosis assays, we were able to show that a cholecalciferol supplementation leads to significantly increased numbers of peripheral Tregs in vivo. Tregs function and the frequency of other immune cells remained unchanged, and no clinically relevant safety concerns were found. The in vitro exposure of human peripheral blood mononuclear cells to cholecalciferol also supported our in vivo findings. CONCLUSIONS: Our results indicate a substantial effect of a supplementation with inactive vitamin D on the immune system of healthy humans in vivo and provide a rationale for future studies to investigate the immunomodulatory effects of vitamin D in autoimmune diseases.

The effect of vitamin D supplementation on peripheral regulatory T cells and ß cell function in healthy humans: a randomized controlled trial.

BACKGROUND: Increasing evidence supports the role of vitamin D (vitD) in modifying the risk to develop type 1 diabetes (T1D) and other autoimmune diseases. VitD3 might stimulate regulatory T cells (Tregs), a central player in the maintenance of self-tolerance. In addition, direct effects of vitD on ß-cell function are postulated. The aim of our study was to evaluate the effect of a high dose vitD supplementation on Tregs frequency (%Tregs) and ß-cell function assessed by a mixed meal tolerance test (MMTT) in healthy humans. METHODS: A double-blind, placebo controlled trial was performed in 59 healthy adult subjects (49% females). Subjects received oral vitD3 (140,000 IU monthly) or placebo for 3 months. %Tregs within 20,000 CD4+ T cells of peripheral blood was determined by multi-parametric FACS-analysis. A liquid MMTT was carried out before and after treatment. RESULTS: %Tregs increased significantly in the vitD group, but remained unchanged in the placebo group. Fasting C-peptide concentrations did not change significantly in either group. Similarly, the mean AUC for C-peptide after 3 months and the change in mean values from baseline to the end of the treatment were comparable in both groups. CONCLUSIONS: A short time high dose vitD3 supplementation significantly increased the frequency of Tregs, but did not further improve ß-cell function in apparently healthy subjects. The immunomodulatory potential of vitD might be an important mechanistic link for the association of vitD and T1D.

Genetic predisposition for adult lactose intolerance and relation to diet, bone density, and bone fractures.

UNLABELLED: Evidence that genetic disposition for adult lactose intolerance significantly affects calcium intake, bone density, and fractures in postmenopausal women is presented. PCR-based genotyping of lactase gene polymorphisms may complement diagnostic procedures to identify persons at risk for both lactose malabsorption and osteoporosis. INTRODUCTION: Lactase deficiency is a common autosomal recessive condition resulting in decreased intestinal lactose degradation. A -13910 T/C dimorphism (LCT) near the lactase phlorizin hydrolase gene, reported to be strongly associated with adult lactase nonpersistence, may have an impact on calcium supply, bone density, and osteoporotic fractures in the elderly. MATERIALS AND METHODS: We determined LCT genotypes TT, TC, and CC in 258 postmenopausal women using a polymerase chain reaction-based assay. Genotypes were related to milk intolerance, nutritional calcium intake, intestinal calcium absorption, bone mineral density (BMD), and nonvertebral fractures. RESULTS: Twenty-four percent of all women were found to have CC genotypes and genetic lactase deficiency. Age-adjusted BMD at the hip in CC genotypes and at the spine in CC and TC genotypes was reduced by -7% to -11% depending on the site measured (p = 0.04). LCT(T/C-13910) polymorphisms alone accounted for 2-4% of BMD in a multiple regression model. Bone fracture incidence was significantly associated with CC genotypes (p = 0.001). Milk calcium intake was significantly lower (-55%, p = 0.004) and aversion to milk consumption was significantly higher (+166%, p = 0.01) in women with the CC genotype, but there were no differences in overall dietary calcium intake or in intestinal calcium absorption test values. CONCLUSION: The LCT(T/C-13910) polymorphism is associated with subjective milk intolerance, reduced milk calcium intake, and reduced BMD at the hip and the lumbar spine and may predispose to bone fractures. Genetic testing for lactase deficiency may complement indirect methods in the detection of individuals at risk for both lactose malabsorption and osteoporosis.

Effects of two years of daily teriparatide treatment on BMD in postmenopausal women with severe osteoporosis with and without prior antiresorptive treatment.

Previous antiresorptive (AR) treatment may influence the response to teriparatide. We examined BMD response and safety in a subgroup of 503 postmenopausal women with osteoporosis who received teriparatide for 24 mo. Patients were divided into three groups based on their prior AR treatment: treatment-naïve (n = 84); pretreated with no evidence of inadequate treatment response (n = 134); and pretreated showing an inadequate response to AR treatment (n = 285), which was predefined based on the occurrence of fractures, persistent low BMD, and/or significant BMD loss while on therapy. Changes in BMD from baseline were analyzed using mixed model repeated measures. Lumbar spine BMD increased significantly from baseline at 6, 12, 18, and 24 mo in all three groups. The mean gain in spine BMD over 24 mo was greater in the treatment-naïve group (0.095 g/cm(2); 13.1%) than in the AR pretreated (0.074 g/cm(2); 10.2%; p < 0.005) and inadequate AR responder (0.071 g/cm(2); 9.8%; p < 0.001) groups. The corresponding increases in total hip BMD were 3.8%, 2.3%, and 2.3%, respectively. Early decreases in hip BMD in the inadequate AR responder group were reversed by 18 mo of treatment. Increases in BMD between 18 and 24 mo were highly significant. Nausea (13.3%) and arthralgia (11.7%) were the most commonly reported adverse events. Asymptomatic hypercalcemia was reported in 5.0% of patients. Teriparatide treatment for 24 mo is associated with a significant increase in BMD in patients with and without previous AR use. Prior AR treatment modestly blunted the BMD response to teriparatide. Safety was consistent with current prescribing label information.

Hypovitaminosis D, impaired bone turnover and low bone mass are common in patients with peripheral arterial disease.

Hypovitaminosis D is common in patients with peripheral arterial disease (PAD). Subsequent secondary hyperparathyroidism and osteomalacia contribute to bone pain and myalgias, and so aggravate clinical symptoms of claudication. We evaluated 95 out of 297 patients with angiographically confirmed PAD stages II (pain in the calves and/or thighs only during exercise) or IV (history of, or presence of local ulcers) and compared them with 44 matched healthy controls regarding their medical history, bone density measurements of the femoral neck and calcaneal bone ultrasound. Bone pain, myalgias and mobility restriction as well as routine laboratory parameters, serum vitamin D [25(OH)D], crosslaps (CTX), parathyroid hormone (PTH), osteocalcin (OC) and alkaline phosphatase (AP) were recorded and analysed. 25(OH)D was significantly lower in PAD IV patients (9.6+/-4.6 ng/ml, P<0.0001) as compared to PAD II stages and controls (19.0+/-7.6 and 19.1+/-9.1 ng/ml), paralleled by lower serum calcium [2.24+/-0.02 mmol/l, P=0.0002 versus PAD II (2.36+/-0.02) and P<0.0001 versus controls (2.39+/-0.02)] and higher iPTH serum levels (66.3+/-3.6 pg/ml, P<0.0001) as compared to PAD II patients (45.3+/-3.5) and healthy controls (38.5+/-2.4). Alkaline phosphatase and serum crosslaps values were significantly higher and age-adjusted bone density and bone ultrasound measurements significantly lower in PAD IV patients, who were also twice as likely to have bone pain and myalgias as PAD II patients. Bone ultrasound measurements correlated significantly with both clinical severity and pain as well as serological parameters of bone metabolism. Underlying PAD has a significant impact on bone density and metabolism as well as on bone and muscular pain. Patients with PAD are at high risk for osteoporosis and osteomalacia and should be regularly monitored and treated for their vitamin D deficiencies.

Vitamin D deficiency and secondary hyperparathyroidism are common complications in patients with peripheral arterial disease.

OBJECTIVE: To investigate via the vitamin D status whether patients with peripheral arterial disease (PAD) tend to develop vitamin D deficiency that in turn influences their clinical symptoms. DESIGN: Cross-sectional. SETTING: University hospital. PATIENTS AND PARTICIPANTS: Three hundred twenty-seven patients were evaluated; subjects with secondary causes of bone disease or bone active medication were excluded. One hundred sixty-one patients with either PAD stage II (n = 84) or stage IV (n = 77) were enrolled and compared to 45 age- and sex-matched healthy controls. MEASUREMENTS AND MAIN RESULTS: All patients underwent determinations of serum chemistry, 25-hydroxyvitamin D (vitamin D3) intact parathyroid hormone (iPTH), alkaline phosphatase (ALP), and osteocalcin and were further stratified according to an individual restriction score into 3 groups: mildly, moderately, or severely restricted in daily life due to the underlying disease. Patients with PAD IV showed significantly lower vitamin D3 (P =.0001), and calcium (P =.0001) values and significantly higher iPTH (P =.0001), osteocalcin (P =.0001) and ALP (P =.02) levels as compared to patients with PAD II. Patients considering themselves as severely restricted due to the underlying disease showed lower vitamin D3 and higher iPTH levels than those who described only a moderate (vitamin D3: P <.001; iPTH: P <.01) or mild (vitamin D3: P <.001; iPTH: P <.001) restriction in daily life. CONCLUSION: Patients with PAD IV, especially those who feel severely restricted due to the disease, are at high risk of developing vitamin D deficiency, secondary hyperparathyroidism, and ultimately osteomalacia due to immobilization and subsequent lack of exposure to sunlight, all of which in turn lead to further deterioration. Monitoring of vitamin D metabolism and vitamin D replacement therapy could be a simple, inexpensive approach to mitigating clinical symptoms and improving quality of life in patients with advanced PAD.

Vitamin D receptor initiation codon polymorphism, bone density and inflammatory activity of patients with ankylosing spondylitis.

OBJECTIVES: Osteoporosis is a common finding in ankylosing spondylitis (AS) and may contribute to spinal deformity and bone pain. Bone metabolism as well as inflammatory processes are influenced by the vitamin D receptor gene (VDR). We investigated initiation codon ( FokI) and 3'UTR ( BsmI) polymorphisms of the VDR for whether there could be an association with bone mineral density (BMD) in relation to bone metabolism or inflammatory activity in patients with AS. METHODS: In this study, 104 patients with AS (m/w 71/33, mean age 41+/-12 years) were investigated for their lumbar and femoral BMD by DEXA and in part by QCT measurements and compared to 54 healthy controls. Disease activity indices, serum markers of bone metabolism and inflammation were recorded. FokI and BsmI polymorphisms of the VDR were genotyped using genomic DNA from peripheral leukocytes with present or absent restriction sites defined as alleles " f" and " b" or " F" and " B," respectively. RESULTS: In male AS patients, FokI genotypes were significantly associated with spinal but not with femoral BMD values ( P=0.01) as independent predictors of low BMD, which was also influenced by BMI, and inflammatory and pain indices. CRP and ESR values were also significantly associated with FokI genotypes. BMD in female patients showed no significant association with either FokI or BsmI genotypes of the VDR. CONCLUSION: This is the first evidence that the VDR gene may be involved in BMD differences, bone metabolism and inflammatory processes in ankylosing spondylitis. A possible interaction of the vitamin D system, cytokines and bone could define new diagnostic and therapeutic implications in ankylosing spondylitis.