Functionality and 25-hydroxyvitamin D levels in institutionalized older adults / Funcionalidade e níveis de 25-hidroxivitamina D em idosos institucionalizados

OBJECTIVES: To evaluate the frequency of hypovitaminosis D among older adults and its association with the level of functionality. METHODS: This cross-sectional observational study of older adults residing in a non-profit long-term care facility assessed functionality with the Katz Index of Independence in Activities of Daily Living. Vitamin D levels were classified as: deficient (< 20 ng/mL), insufficient (21-29 ng/mL), or normal (≥ 30 ng/mL). We used the chi-square test and Student's t-test to compare dichotomous and continuous variables, respectively. Analysis of variance with Tukey's post hoc test was used to assess differences between groups. RESULTS: The sample consisted of 63 individuals whose mean age was 81 (61-113) years: 36 (55.4%) women and 27 (44.6%) men. The mean vitamin D level was 18.6 ng/mL, being < 30 ng/mL in 84.1%. The level was normal in 10 (15.9%), insufficient in 17 (27%), and deficient in 36 (57.1%). Vitamin D deficiency was present in 76.5% of those with total functional dependence (Katz = 5-6). CONCLUSIONS: We observed a high frequency of hypovitaminosis D, especially vitamin D deficiency, which was very common among those with significant functional dependence.

OBJETIVOS: Avaliar a frequência de hipovitaminose D em idosos de uma instituição filantrópica de longa permanência e sua associação com grau de funcionalidade. METODOLOGIA: Estudo transversal, observacional e analítico de idosos de uma instituição filantrópica de longa permanência. A funcionalidade foi avaliada pela Escala de Katz. Os níveis de vitamina D foram classificados em: deficiência (valores menores que 20 ng/mL); insuficiência (valores entre 21 - 29 ng/mL) e normais (valores igual ou superior a 30 ng/mL). Empregamos teste qui-quadrado e t de student, para compararmos variáveis dicotômicas e contínuas, respectivamente; e análise de variância (ANOVA) com teste post hoc de Tukey, para avaliarmos as diferenças entre os grupos. RESULTADOS: Sessenta e três indivíduos foram analisados com média de idade de 81 anos (61 - 113), sendo 36 (55,4%) mulheres e 27 (44,6%) homens. A média de vitamina D foi 18,6 ng/mL, 84,1% com níveis menores que 30 ng/mL; dez apresentaram níveis normais (15,9%), 17 com insuficiência (27%) e 36 com deficiência (57,1%); ainda, 76,5% dos portadores de dependência funcional total (Katz = 5 - 6) apresentam deficiência de vitamina D. CONCLUSÕES: Observamos uma alta frequência de hipovitaminose D, especialmente deficiência, muito frequentes naqueles com dependência funcional importante

Intake of ergosterol increases the vitamin D concentrations in serum and liver of mice.

Factors that can modify the bioavailability of orally administered vitamin D are not yet widely known. Ergosterol is a common fungal sterol found in food which has a chemical structure comparable to that of vitamin D. This study aimed to investigate the effect of ergosterol on vitamin D metabolism. Therefore, 36 male wild type-mice were randomly subdivided into three groups (n = 12) and received a diet containing 25 µg vitamin D3 and either 0 mg (control), 2 mg or 7 mg ergosterol per kg diet for 6 weeks. To elucidate the impact of ergosterol on hepatic hydroxylation of vitamin D, human hepatoma cells (HepG2) were treated with different concentrations of ergosterol. Concentrations of vitamin D3 and 25-hydroxyvitamin D3 (25(OH)D3) in cells, livers and kidneys of mice and additionally 24,25-dihydroxyvitamin D3 (24,25(OH)2D3) in serum were quantified by LC-MS/MS. The concentration of 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) in serum was analyzed by commercially-available enzyme immuno assay. The concentrations of cholesterol and triglycerides were analyzed in livers of mice by photometric assays. Analyses revealed that mice receiving 7 mg/kg ergosterol with their diet had 1.3-, 1.7- and 1.5-times higher concentrations of vitamin D3 in serum, liver and kidney, respectively, than control mice (P < 0.05), whereas no significant effects were observed in mice fed 2 mg/kg ergosterol. The hydroxylation of vitamin D remained unaffected by dietary ergosterol, since the concentration of 25-hydroxyvitamin D3 in serum and tissues and the concentrations of 1,25(OH)2D3 and 24,25(OH)2D3 in serum were not different between the three groups of mice. The lipid concentrations in liver were also not affected by dietary ergosterol. Data from the cell culture studies showed that ergosterol did not influence the conversion of vitamin D3 to 25(OH)D3. To conclude, ergosterol appears to be a modulator of vitamin D3 concentrations in the body of mice, without modulating the hydroxylation of vitamin D3 in liver.

Increase of 1,25 dihydroxyvitamin D in sarcoidosis patients with renal dysfunction.

INTRODUCTION: In sarcoidosis, renal involvement includes hypercalcemia-related nephrocalcinosis and granulomatous tubulointerstitial nephritis. Hypercalcemia is thought to be due to increased production of 1,25 dihydroxyvitamin D (1-25D), but 1-25D levels have not been evaluated in sarcoidosis patients with renal dysfunction. MATERIALS AND METHODS: We enrolled 9 sarcoidosis patients who underwent renal biopsy, and compared the serum 1-25D concentration and eGFR with those in 428 non-sarcoidosis patients who had renal dysfunction (stage 2 or higher CKD with an estimated glomerular filtration rate < 90). RESULTS: Serum calcium and 1-25D levels were significantly higher in the sarcoidosis patients than in the non-sarcoidosis patients (p < 0.01 and p = 0.01, respectively). There was a positive correlation between 1-25D and eGFR in the patients without sarcoidosis (r = 0.693; p < 0.01). As the renal function of sarcoidosis patients was improved by steroid therapy, the serum 1-25D and adjusted serum calcium levels decreased to near the median values in non-sarcoidosis patients. On renal biopsy, CD68 staining was positive for tissue macrophages in all 8 patients who had tubulointerstitial nephritis (with or without typical granulomas), while Von Kossa staining showed calcification of tubules near or inside granulomas in 6 of these 8 patients. CONCLUSION: While tissue macrophages promote development of tubulointerstitial nephritis and 1-25D overproduction in renal sarcoidosis, hypercalcemia secondary to elevation of 1-25D may be related to renal calcification and granuloma formation.

Magnesium status and supplementation influence vitamin D status and metabolism: results from a randomized trial.

Background: Previous in vitro and in vivo studies indicate that enzymes that synthesize and metabolize vitamin D are magnesium dependent. Recent observational studies found that magnesium intake significantly interacted with vitamin D in relation to vitamin D status and risk of mortality. According to NHANES, 79% of US adults do not meet their Recommended Dietary Allowance of magnesium. Objectives: The aim of this study was to test the hypothesis that magnesium supplementation differentially affects vitamin D metabolism dependent on baseline 25-hydroxyvitamin D [25(OH)D] concentration. Methods: The study included 180 participants aged 40-85 y and is a National Cancer Institute independently funded ancillary study, nested within the Personalized Prevention of Colorectal Cancer Trial (PPCCT), which enrolled 250 participants. The PPCCT is a double-blind 2 × 2 factorial randomized controlled trial conducted in the Vanderbilt University Medical Center. Doses for both magnesium and placebo were customized based on baseline dietary intakes. Subjects were randomly assigned to treatments using a permuted-block randomization algorithm. Changes in plasma 25-hydroxyvitamin D3 [25(OH)D3], 25-hydroxyvitamin D2 [25(OH)D2], 1,25-dihydroxyvitamin D3, 1,25-dihydroxyvitamin D2, and 24,25-dihydroxyvitamin D3 [24,25(OH)2D3] were measured by liquid chromatography-mass spectrometry. Results: The relations between magnesium treatment and plasma concentrations of 25(OH)D3, 25(OH)D2, and 24,25(OH)2D3 were significantly different dependent on the baseline concentrations of 25(OH)D, and significant interactions persisted after Bonferroni corrections. Magnesium supplementation increased the 25(OH)D3 concentration when baseline 25(OH)D concentrations were close to 30 ng/mL, but decreased it when baseline 25(OH)D was higher (from ∼30 to 50 ng/mL). Magnesium treatment significantly affected 24,25(OH)2D3 concentration when baseline 25(OH)D concentration was 50 ng/mL but not 30 ng/mL. On the other hand, magnesium treatment increased 25(OH)D2 as baseline 25(OH)D increased. Conclusion: Our findings suggest that optimal magnesium status may be important for optimizing 25(OH)D status. This trial was registered at clinicaltrials.gov as NCT03265483.

Ancestry-Adjusted Vitamin D Metabolite Concentrations in Association With Cytochrome P450 3A Polymorphisms.

We investigated the association between genetic polymorphisms in cytochrome P450 (CYP2R1, CYP24A1, and the CYP3A family) with nonsummer plasma concentrations of vitamin D metabolites (25-hydroxyvitamin D3 (25(OH)D3) and proportion 24,25-dihydroxyvitamin D3 (24,25(OH)2D3)) among healthy individuals of sub-Saharan African and European ancestry, matched on age (within 5 years; n = 188 in each ancestral group), in central suburban Pennsylvania (2006-2009). Vitamin D metabolites were measured using high-performance liquid chromatography with tandem mass spectrometry. Paired multiple regression and adjusted least-squares mean analyses were used to test for associations between genotype and log-transformed metabolite concentrations, adjusted for age, sex, proportion of West-African genetic ancestry, body mass index, oral contraceptive (OC) use, tanning bed use, vitamin D intake, days from summer solstice, time of day of blood draw, and isoforms of the vitamin D receptor (VDR) and vitamin D binding protein. Polymorphisms in CYP2R1, CYP3A43, vitamin D binding protein, and genetic ancestry proportion remained associated with plasma 25(OH)D3 after adjustment. Only CYP3A43 and VDR polymorphisms were associated with proportion 24,25(OH)2D3. Magnitudes of association with 25(OH)D3 were similar for CYP3A43, tanning bed use, and OC use. Significant least-squares mean interactions (CYP2R1/OC use (P = 0.030) and CYP3A43/VDR (P = 0.013)) were identified. A CYP3A43 genotype, previously implicated in cancer, is strongly associated with biomarkers of vitamin D metabolism. Interactive associations should be further investigated.

The vitamin D metabolite ratio (VMR) as a predictor of functional biomarkers of bone health.

CONTEXT: The vitamin D metabolite ratio (VMR) (serum 24,25(OH)2 D3 /25(OH)D3 ) has been proposed as a biomarker of vitamin D sufficiency to replace serum 25(OH)D. OBJECTIVE: To examine the relationships of 24,25(OH)2 D3 and VMR to functional biomarkers of bone health following vitamin D supplementation. SETTING: An ambulatory research centre. DESIGN: Serum from a previous research study of dose response of PTH, calcium absorption and bone turnover to vitamin D supplementation was analysed for vitamin D metabolites (25(OH)D, 24,25(OH)2 D3 ). OUTCOME: The relationship of serum 24,25(OH)2 D3 and VMR to calcium absorption, PTH and bone turnover markers was examined. RESULTS: Although there were strong correlations of serum 25(OH)D with 24,25(OH)2 D3 and free 25(OH)D, its correlation with VMR was lower. After vitamin D supplementation, the change in 25(OH)D, 24,25(OH)2 D3 and VMR was associated with the change in calcium absorption, PTH and CTX. The correlation of the change in PTH with the change in metabolites was the lowest for VMR. Moreover, estimated dose response for standardized values of vitamin D metabolites showed a beta-coefficient for VMR that was significantly less in magnitude compared to other metabolites. CONCLUSION: Serum 24,25(OH)2 D3 is closely associated with the dose response of serum 25(OH)D to vitamin D supplementation. However, the VMR does not appear to be equivalent to either of these metabolites in its response to increasing vitamin D intake or its association with PTH. It is unlikely that VMR will replace 25(OH)D as a biomarker for vitamin D sufficiency.

[Assessment of Vitamin D Metabolism by LC-MS/MS].

Vitamin D is pro-hormone that has important roles in calcium metabolism in the intestine, kidneys, and bone. Many studies have indicated that vitamin D deficiency causes not only rickets and osteomalacia, but also increases the risk of various diseases such as cancer and autoimmune disease. Of the many vitamin D metabolites, 25-hydroxyvitamin D[25OH-D], 1α,25-dihydroxyvitamin D[1,25(OH)2-D], and 24,25-dihydroxyvitamin D [24,25 (OH) 2-D] are important for assessing vitamin D metabolism. They are circulating, biologically active, and major inactive forms of vitamin D metabolite, respectively. Immunoassays are widely used for the measurement of serum/plasma vitamin D metabolites. With such an assay, however, the accurate quantification of these metabolites is difficult because of cross-reactivity. Liquid chromatography-tandem mass spectrometry [LC-MS/MS] is the gold standard method for analyzing these metabolites due to its high sensitivity and selectivity. Derivatization with a Cookson-type reagent is a key technique for robust and sensitive analysis by LC-MS/MS. A Cookson-type reagent rapidly and quantitatively reacts with the s-cis-diene structure of vitamin D metabolites, and markedly enhances the ionization efficiency. Using a recently developed Cookson-type reagent (DAPTAD), we successfully established an LC-MS/MS-based method for analyzing serum vitamin D metabolites including 250H-D, 1,25 (OH) 2-D, and 24,25 (OH) 2-D. Thus, LC-MS/MS can be a powerful tool for the accurate determination of vitamin D metabolism. In this review, we describe the advantages of LC-MS/MS for the determination of vitamin D metabolites.

Serum vitamin D3 does not correlate with liver fibrosis in chronic hepatitis C.

AIM: To investigate the relationship between serum vitamin D3 levels and liver fibrosis or inflammation in treatment-naive Chinese patients with chronic hepatitis C (CHC). METHODS: From July 2010 to June 2011, we enrolled 122 CHC patients and 11 healthy controls from Dingxi city, Gansu Province, China. The patients were infected with Hepatitis C virus (HCV) during blood cell re-transfusion following plasma donation in 1992-1995, and had never received antiviral treatment. At present, all the patients except two underwent liver biopsy with ultrasound guidance. The Scheuer Scoring System was used to evaluate hepatic inflammation and the Metavir Scoring System was used to evaluate hepatic fibrosis. Twelve-hour overnight fasting blood samples were collected in the morning of the day of biopsy. Serum levels of alanine aminotransferase, aspartate aminotransferase, total bilirubin, direct bilirubin, cholinesterase, prothrombin activity, albumin, γ-glutamyl transpeptidase, hemoglobin, calcium and phosphorus were determined. Serum HCV RNA levels were measured by real-time PCR. Serum levels of 25-hydroxyvitamin D3 [25(OH)D3] and 24,25-dihydroxyvitamin D3 [24,25(OH)2D3] were measured by high-performance liquid chromatography tandem mass spectrometry. RESULTS: Serum levels of 25(OH)D3 but not 24,25(OH)2D3 were significantly lower in CHC patients than in control subjects. Serum 25(OH)D3 levels did not correlate with liver fibrosis, inflammation, patient age, or levels of alanine aminotransferase, aspartate aminotransferase, total bilirubin, direct bilirubin, prothrombin activity, cholinesterase or HCV RNA. However, serum 25(OH)D3 levels did correlate with serum 24,25(OH)2D3 levels. Serum 25(OH)D3 and 24,25(OH)2D3 levels, and the 25(OH)D3/24,25(OH)2D3 ratio, have no difference among the fibrosis stages or inflammation grades. CONCLUSION: We found that serum levels of 25(OH)D3 and its degradation metabolite 24,25(OH)2D3 did not correlate with liver fibrosis in treatment-naive Chinese patient with CHC.

Dietary vitamin D inadequacy accelerates calcification and osteoblast-like cell formation in the vascular system of LDL receptor knockout and wild-type mice.

Vitamin D insufficiency is highly associated with cardiovascular morbidity and mortality. We have demonstrated enhanced vascular calcification in LDL receptor knockout (LDLR(-/-)) mice fed a diet low in vitamin D. This study aimed to investigate the impact of a diet low in vitamin D on vascular calcification in wild-type (WT) mice lacking atherosclerotic plaques and the effects of a persistent and discontinuous vitamin D insufficiency on atherosclerotic plaque composition in LDLR(-/-) mice. The study was performed with 4-wk-old male WT and LDLR(-/-) mice that were fed a normal calcium/phosphate Western diet (210 g/kg fat, 1.5 g/kg cholesterol) containing either adequate (+D; 1000 IU/kg) or low (-D; 50 IU/kg) amounts of vitamin D-3 for 16 wk. Four groups of LDLR(-/-) mice received 1 of the 2 diets for additional 16 wk (total 32 wk) and were compared with mice fed the diets for only 16 wk. WT and LDLR(-/-) mice that were fed the -D diet for 16 wk tended to develop more calcified spots in the aortic valve than mice fed the +D diet (+50% and +56%, respectively; P < 0.10). In LDLR(-/-) mice, the extent of calcification increased from week 16 to week 32 and was higher in the -D than in the +D group (P < 0.05). The calcification, owing to the -D diet, was accompanied by highly expressed osteoblast differentiation factors, indicating a transdifferentiation of vascular cells to osteoblast-like cells. Feeding the +D diet subsequent to the -D diet reduced the vascular calcification (P < 0.05). LDLR(-/-) mice fed the -D diet for 32 wk had higher plaque lipid depositions (+48%, P < 0.05) and a higher expression of cluster of differentiation 68 (+31%, P < 0.05) and tumor necrosis factor α (+134%, P < 0.001) than the +D group. Collectively, the findings imply low vitamin D status as a causal factor for vascular calcification and atherosclerosis.

Markers of the APC/ß-catenin signaling pathway as potential treatable, preneoplastic biomarkers of risk for colorectal neoplasms.

BACKGROUND: Malfunctioning of the adenomatous polyposis coli (APC)/ß-catenin signaling pathway is both an early and common event in sporadic colorectal cancer. To assess the potential of APC/ß-catenin signaling pathway markers as treatable, preneoplastic biomarkers of risk for colorectal neoplasms, we conducted a pilot colonoscopy-based case-control study (51 cases and 154 controls) of incident, sporadic colorectal adenoma. METHODS: We evaluated APC, ß-catenin, and E-cadherin expression in normal mucosa from the rectum and ascending and sigmoid colon using automated immunohistochemical and quantitative image analysis. Diet, lifestyle, and medical history were assessed with validated questionnaires. RESULTS: In the normal rectal mucosa, the ratio of the proportion of APC expression in the upper 40% of crypts with total ß-catenin expression (APC/ß-catenin score) was 14.3% greater in controls than in cases [P = 0.02; OR, 0.40; 95% confidence interval (CI), 0.14-1.14]. Compared with controls, in cases, APC expression was 3.2% lower, ß-catenin expression was 3.0% higher, and E-cadherin expression was 0.7% lower; however, none of these differences were statistically significant. The APC/ß-catenin score statistically significantly differed according to categories of plausible risk factors for colorectal cancer [e.g., it was 17.7% higher among those with 25(OH) vitamin D(3) concentrations ≥ 27 ng/mL]. CONCLUSIONS: These preliminary data suggest that the combined expression of APC and ß-catenin in the normal rectal mucosa may be associated with risk for incident, sporadic colorectal neoplasms, as well as with modifiable risk factors for colorectal neoplasms. IMPACT: Our results may help advance the development of treatable, preneoplastic biomarkers of risk for colorectal neoplasms.

The impact of vitamin D status on periodontal surgery outcomes.

Vitamin D regulates calcium and immune function. While vitamin D deficiency has been associated with periodontitis, little information exists regarding its effect on wound healing and periodontal surgery outcomes. This longitudinal clinical trial assessed outcomes of periodontal surgery and teriparatide administration in vitamin-D-sufficient and -insufficient individuals. Forty individuals with severe chronic periodontitis received periodontal surgery, daily calcium and vitamin D supplements, and self-administered teriparatide or placebo for 6 wks to correspond with osseous healing time. Serum 25(OH)D was evaluated at baseline, 6 wks, and 6 mos post-surgery. Clinical and radiographic outcomes were evaluated over 1 yr. Placebo patients with baseline vitamin D deficiency [serum 25(OH)D, 16-19 ng/mL] had significantly less clinical attachment loss (CAL) gain (-0.43 mm vs. 0.92 mm, p < 0.01) and probing depth (PPD) reduction (0.43 mm vs. 1.83 mm, p < 0.01) than vitamin-D-sufficient individuals. Vitamin D levels had no significant impact on CAL and PPD improvements in teriparatide patients at 1 yr, but infrabony defect resolution was greater in teriparatide-treated vitamin-D-sufficient vs. -deficient individuals (2.05 mm vs. 0.87 mm, p = 0.03). Vitamin D deficiency at the time of periodontal surgery negatively affects treatment outcomes for up to 1 yr. Analysis of these data suggests that vitamin D status may be critical for post-surgical healing. (ClinicalTrials.gov number, CT00277706).

Short-term individual nutritional care as part of routine clinical setting improves outcome and quality of life in malnourished medical patients.

BACKGROUND & AIMS: Strategies to treat malnutrition lack practicability in the hospital setting. The present study aimed at developing and evaluating a routinely manageable concept for an improved nutritional care of malnourished in-hospital patients. METHODS: A randomized controlled intervention study was conducted. 132 risk patients defined by Nutritional Risk Screening 2002, were randomized to individualised nutrition support (intervention group [n = 66]) or standard hospital care (control group [n = 66]). Body weight, plasma vitamin levels, quality of life, complications, antibiotic therapies, readmissions and mortality were assessed. RESULTS: Nutrition interventions led to higher intakes (mean [standard deviation]) in energy (1553 [341] kcal vs. 1115 [381] kcal, p < 0.001) and protein (65.4 [16.4] g vs. 43.9 [17.2] g, p < 0.001). Intervention patients (n = 66) kept their body weight in comparison to control patients (n = 66; 0.0 [2.9] kg vs. -1.4 [3.2] kg, p = 0.008). Positive effects on plasma ascorbic acid level (46.7 [26.7] µmol/l vs. 34.1 [24.2] µmol/l, p = 0.010), SF-36 function summary scale (37 [11] % vs. 32 [9] %, p = 0.030), number of complications (4/66 vs. 13/66, p = 0.035), antibiotic therapies (1/66 vs. 8/66, p = 0.033) and readmissions (17/64 vs. 28/61, p = 0.027) were recorded. CONCLUSIONS: Malnourished patients profit from nutrition support regarding nutrition status and quality of life. They have fewer complications, need fewer antibiotics and are less often re-hospitalised.

Prevention of rickets and vitamin D deficiency in infants, children, and adolescents.

Rickets in infants attributable to inadequate vitamin D intake and decreased exposure to sunlight continues to be reported in the United States. There are also concerns for vitamin D deficiency in older children and adolescents. Because there are limited natural dietary sources of vitamin D and adequate sunshine exposure for the cutaneous synthesis of vitamin D is not easily determined for a given individual and may increase the risk of skin cancer, the recommendations to ensure adequate vitamin D status have been revised to include all infants, including those who are exclusively breastfed and older children and adolescents. It is now recommended that all infants and children, including adolescents, have a minimum daily intake of 400 IU of vitamin D beginning soon after birth. The current recommendation replaces the previous recommendation of a minimum daily intake of 200 IU/day of vitamin D supplementation beginning in the first 2 months after birth and continuing through adolescence. These revised guidelines for vitamin D intake for healthy infants, children, and adolescents are based on evidence from new clinical trials and the historical precedence of safely giving 400 IU of vitamin D per day in the pediatric and adolescent population. New evidence supports a potential role for vitamin D in maintaining innate immunity and preventing diseases such as diabetes and cancer. The new data may eventually refine what constitutes vitamin D sufficiency or deficiency.

Changes in vitamin D after gastrectomy.

BACKGROUND: We previously reported that the administration of 1alpha hydroxy vitamin D3 was effective for treating post-gastrectomy bone disorders. Accordingly, we performed the present study to obtain evidence supporting the effectiveness of 1alpha hydroxy vitamin D3 in post-gastrectomy patients. METHODS: The study involved 22 outpatients who had undergone gastrectomy for gastric cancer and had not been treated with 1alpha hydroxy vitamin D3 or calcium. They comprised 17 men and 5 women, with a mean age of 61.9 years. Laboratory tests were performed to examine the following parameters: 1,25(OH)(2) vitamin D3; 25(OH) vitamin D3; 24,25(OH)(2) vitamin D3; ionized calcium; calcium; phosphorus; alkaline phosphatase; N-parathyroid hormone; and osteocalcin. RESULTS: The level of 1,25(OH)(2) vitamin D3, the most active of the vitamin D metabolites, was found to be normal in all of the patients. In contrast, the level of 25(OH) vitamin D3, which shows weak activity, was below the normal range in 7 of the 22 patients (31.8%). The mean serum level of 25(OH) vitamin D3 was significantly lower in patients at 1 year or more postoperatively than the level in those at less than 1 year postoperatively (P = 0.041), as well as being significantly lower in patients who had received total gastrectomy than in patients who underwent other gastrectomy procedures. The level of 24,25(OH)(2) vitamin D3, a metabolite of 25(OH) vitamin D3 that shows weak activity, was below the normal range in 19 of the 22 patients (86.4%). On multivariate analyses, factors associated with the change in vitamin D metabolites did not remain. CONCLUSION: The patients showed a decrease of 25(OH) vitamin D3 and 24,25(OH)(2) vitamin D3, which are metabolites that show weak activity. This suggests that a homeostatic response maintains the normal level of 1,25(OH)(2) vitamin D3, which is important for calcium regulation. Thus, it was suggested that gastrectomy had a moderate influence on the metabolism of vitamin D. However we could not detect any factor associated with the decrease of 25(OH) vitamin D3 and 24,25(OH)(2) vitamin D3.

Current criteria for hip fracture risk assessment--are we missing something?

BACKGROUND: Hip fracture rates are increasing worldwide, and the risk for a second hip fracture is high. The decision to administer antiresorptive treatment is based mainly on bone mineral density and/or a history of previous osteoporotic fractures. OBJECTIVES: To evaluate the contribution of BMD, previous fractures, clinical and laboratory parameters to hip fracture risk assessment. METHODS: The study population included 113 consecutive hip fracture patients, aged 72.5 +/- 9.4 years, discharged from the orthopedic surgery department. BMD was assessed at the lumbar spine, femoral neck and total hip. The results were expressed in standard deviation scores as T-scores--compared to young adults and Z-scores--compared to age-matched controls. Plasma or serum levels of parathyroid hormone, 25-hydroxyvitamin 3 and urinary deoxypyridinoline cross-links were evaluated. RESULTS: We observed T-scores < or = 2.5 in 43 patients (45.3%) at the lumbar spine, in 47 (52.2%) at the femoral neck and in 33 (38%) at the total hip. Twenty-eight patients (29.5%) had neither low BMD nor previous osteoporotic fractures. Using a T-score cutoff point of (-1.5) at any measurement site would put 25 (89%) of these patients into the high fracture risk group. Mean DPD level was 15.9 +/- 5.8 ng/mg (normal 4-7.3 ng/mg creatinine). Vitamin D inadequacy was observed in 99% of patients. CONCLUSIONS: Using current criteria, about one-third of elderly hip fracture patients might not have been diagnosed as being at risk. Lowering the BMD cutoff point for patients with additional risk factors may improve risk prediction yield.

The role of Vitamin D3 metabolism in prostate cancer.

Vitamin D deficiency increases risk of prostate cancer. According to our recent results, the key Vitamin D hormone involved in the regulation of cell proliferation in prostate is 25(OH) Vitamin D3. It is mainly acting directly through the Vitamin D receptor (VDR), but partially also through its 1alpha-hydroxylation in the prostate. A deficiency of 25(OH) Vitamin D is common especially during the winter season in the Northern and Southern latitudes due to an insufficient sun exposure, but Vitamin D deficient diet may partially contribute to it. A lack of Vitamin D action may also be due to an altered metabolism or Vitamin D resistance. Vitamin D resistance might be brought up by several mechanisms: Firstly, an increased 24-hydroxylation may increase the inactivation of hormonal Vitamin D metabolites resulting in a Vitamin D resistance. This is obvious in the cancers in which an oncogenic amplification of 24-hydroxykase gene takes place, although an amplification of this gene in prostate cancer has not yet been described. During the aging, the activity of 24-hydroxylase increases, whereas 1alpha-hydroxylation decreases. Furthermore, it is possible that a high serum concentration of 25(OH)D3 could induce 24-hydroxylase expression in prostate. Secondly, Vitamin D receptor gene polymorphism or defects may result in a partial or complete Vitamin D resistance. Thirdly, an overexpression or hyperphosphorylation of retinoblastoma protein may result in an inefficient mitotic control by Vitamin D. Fourthly, endogenous steroids (reviewed by [D.M. Peehl, D. Feldman, Interaction of nuclear receptor ligands with the Vitamin D signaling pathway in prostate cancer, J. Steroid Biochem. Mol. Biol. (2004)]) and phytoestrogens may modulate the expression of Vitamin D metabolizing enzymes. In summary, the local metabolism of hormonal Vitamin D seems to play an important role in the development and progression of prostate cancer.

Osteoporosis, bone turnover and hypogonadism in elderly men with treated leprosy.

In male hypogonadism associated with bone loss, it is important to determine whether bone loss continues with ageing and an increased risk of fracture. We studied bone metabolism in 86 male leprosy patients, who were classified according to the presence or absence of osteoporosis. Osteoporosis was present when men had lumbar compression fractures or a mean BMD-2SD that of normal Japanese men in each age decade. Four men had fractures. Serum concentrations of 1,25-dihydroxyvitamin D and high-sensitivity parathyroid hormone were almost normal in both groups, whereas free testosterone and oestradiol were significantly lower in the osteoporosis group than in the non-osteoporosis group (free testosterone: P < 0.01, oestradiol: P < 0.05). The urinary concentrations of pyridinoline and deoxypyridinoline, as a marker of bone absorption, were significantly higher in the osteoporosis group than in the non-osteoporosis group (pyridinoline: P < 0.01, deoxypyridinoline: P < 0.01). The serum concentration of osteocalcin, a marker of bone formation, was significantly higher in the osteoporosis group than in the non-osteoporosis group (P < 0.01). Elevated concentration means that bone repair is increased possibly because of compensation mechanisms for increased bone loss. In the osteoporosis group, hypogonadism occurred, and high bone turnover continued even in older men. We recommend clinical studies of treatment such as replacement therapy to prevent bone loss and increasing risk of fractures in older men with leprosy.

Conflicting actions of parathyroid hormone-related protein and serum calcium as regulators of 25-hydroxyvitamin D(3)-1 alpha-hydroxylase expression in a nude rat model of humoral hypercalcemia of malignancy.

In patients with humoral hypercalcemia of malignancy (HHM), serum levels of 1,25-dihydroxyvitamin D (1,25(OH)(2)D) are generally low, although the pathophysiology of the impaired vitamin D metabolism is not fully understood. In the present study, we have investigated vitamin D metabolism in our newly developed rat model of HHM in which a human infantile fibrosarcoma producing parathyroid hormone-related protein (PTHrP), named OMC-1, was inoculated s.c. into athymic nude rats. In OMC-1-bearing rats, the serum concentration of 1,25(OH)(2)D was markedly reduced when the animals exhibited severe hypercalcemia (Ca > or =15 mg/dl), while it was rather elevated in those with mild hypercalcemia. To further examine whether serum Ca levels affect 1,25(OH)(2)D concentration, we administered bisphosphonate YM529 to OMC-1-bearing rats when they exhibited severe hypercalcemia. The restoration of the serum Ca level by administration of YM529 was accompanied by a marked increase in the 1,25(OH)(2)D level, suggesting that the serum Ca level itself plays an important role in the regulation of the 1,25(OH)(2)D level in these rats. On the other hand, when the OMC-1-bearing rats were treated with a neutralizing antibody against PTHrP, serum 1,25(OH)(2)D levels remained low despite the reduction in serum Ca levels. Expression of 25-hydroxyvitamin D-1 alpha-hydroxylase (1 alpha-hydroxylase) in kidney was decreased in OMC-1-bearing rats with severe hypercalcemia, and markedly enhanced after treatment with bisphosphonate. This enhancement in 1 alpha-hydroxylase expression was not observed after treatment with the antibody against PTHrP. These results suggest that PTHrP was responsible for the enhanced expression of 1 alpha-hydroxylase in YM529-treated rats, and that hypercalcemia played a role in reducing the serum 1,25(OH)(2)D level in OMC-1-bearing rats by suppressing the PTHrP-induced expression of the 1 alpha-hydroxylase gene.

Measurement of vitamin D3 metabolites in smelter workers exposed to lead and cadmium.

OBJECTIVES: To investigate the effects of lead and cadmium on the metabolic pathway of vitamin D3. METHODS: Blood and urinary cadmium and urinary total proteins were measured in 59 smelter workers occupationally exposed to lead and cadmium. In 19 of these workers, the plasma vitamin D3 metabolites, (25-hydroxycholecalciferol (25 OHD3), 24R, 25-dihydroxycholecalciferol (24R,25(OH)2D3) and 1 alpha,25-dihydroxycholecalciferol (1 alpha, 25(OH)2D3)) were measured together with blood lead. Vitamin D3 metabolites were measured by radioimmunoassay, (RIA), lead and cadmium by atomic absorption spectrophotometry, and total proteins with a test kit. RESULTS: Ranges for plasma 25(OH)D3, 24R,25(OH)2D3 and 1 alpha,25(OH)2D3 were 1.0-51.9 ng/ml, 0.6-5.8 ng/ml, and 0.1-75.7 pg/ml, respectively. Ranges for blood lead were 1-3.7 mumol/l, (21-76 micrograms/dl), blood cadmium 6-145 nmol/l, and urinary cadmium 3-161 nmol/l. Total proteins in random urine samples were 2.1-32.6 mg/dl. Concentrations of lead and cadmium in blood showed no correlation (correlation coefficient -0.265) but there was a highly significant correlation between blood and urinary cadmium. Concentrations for 24R,25(OH)2D3 were depressed below the normal range as blood and urinary cadmium increased, irrespective of lead concentrations. High cadmium concentrations were associated with decreased plasma 1 alpha,25(OH)2D3 when lead concentrations were < 1.9 mumol/l and with above normal plasma 1 alpha,25(OH)2D3 when lead concentrations were > 1.9 mumol/l, Kruskal-Wallis analysis of variance (K-W ANOVA) chi 2 = 10.3, p = 0.006. Plasma 25(OH)D3 was negatively correlated with both urinary total proteins and urinary cadmium, but showed no correlation with plasma 24R,25(OH)2D3, 1 alpha,25(OH)2D3, blood lead, or blood cadmium. CONCLUSION: Continuous long term exposure to cadmium may result in a state of equilibrium between blood and urinary cadmium. Cadmium concentrations in blood could be predicted from the cadmium concentration of the urine, (regression coefficient +0.35 SE 0.077). Exposure to cadmium alone decreased the concentrations of 1 alpha,25(OH)2D3 and 24R,25(OH)2D3, whereas exposure to both cadmium and lead increased the concentrations of 1 alpha,25(OH)2D3. It has been suggested that cadmium and lead interact with renal mitochondrial hydroxylases of the vitamin D3 endocrine complex. Perturbation of the vitamin D metabolic pathway by cadmium may result in health effect, such as osteoporosis or osteomalacia, risks which are possibly increased in the presence of lead.

A novel high-performance liquid chromatographic assay for vitamin D metabolites using a coulometric electrochemical detector.

A new, highly sensitive HPLC assay method using an electrochemical detector (ECD) for multiple assay of vitamin D metabolites is reported. The assay involves extracting lipids from plasma with methylene chloride and methanol, purification on Zorbax SIL column with 5.5% (v/v) iso-propanol in hexane and quantification by HPLC-ECD. A coulometric system, composed of the dual electrode analytical cell and a guard cell, was used for ECD of the eluting compounds. The potentials applied to detectors 1 and 2 in a dual electrode analytical cell were adjusted to +0.20 V and +0.60 V, respectively. This method is sensitive to 20 pg of 25-hydroxyvitamin D3 [25(OH)D3] and of 24R,25-dihydroxyvitamin D3 [24,25(OH)2D3]. Calibration curves gave linearity from 20-1000 pg for 25(OH)D3 and 24,25(OH)2D3. The detection limit was approximately 50 pg ml-1 for 25(OH)D3 and 24,25(OH)2D3 in plasma. This sensitivity combined with an overall recovery of 25(OH)D3 (81.5 +/- 2.6%, mean +/- S.E.) allows the measurement of trace amount of 25(OH)D3 with only 20 microliters of plasma. Intra- and interassay RSD values were 5.3 and 9.7% for 25(OH)D3 and 6.3 and 9.7% for 24,25(OH)2D3, respectively. Plasma levels of 25(OH)D3 and 24,25(OH)2D3 in normal adults were 15.9 +/- 2.8 ng ml-1 (n = 10) and 1.4 +/- 0.5 ng ml-1 (n = 10), respectively. This method allows the determination of 25(OH)D2 and 25(OH)D3 for evaluating their nutritional and clinical status. From these results, it is concluded that the proposed HPLC-ECD assay system is useful for the determination of vitamin D metabolites in biological fluids as a highly sensitive physicochemical method.