Low serum vitamin D levels are associated with shorter survival after first-line azacitidine treatment in patients with myelodysplastic syndrome and secondary oligoblastic acute myeloid leukemia.

BACKGROUND & AIMS: Azacitidine (AZA) therapy has become the recommended first-line treatment for patients with high-risk myelodysplastic syndromes (MDS) and oligoblastic (<30% bone marrow blasts) acute myeloid leukemia (AML). However, improvement of the efficacy of AZA treatment remains a challenge. We retrospectively tested the hypothesis that VitD levels (25-hydroxyvitamin D3) prior to start of first-line AZA therapy are predictive of overall survival (OS) in patients diagnosed with MDS and secondary oligoblastic AML. Furthermore, the antiproliferative effects of AZA in combination with 25-hydroxyvitamin D3 and 1α,25-dihydroxyvitamin D3 were investigated in vitro. METHODS: A total of 58 patients treated at our center between 2006 and 2014 were analyzed. Serum levels of VitD were quantified using a standard, commercially available 25-hydroxyvitamin D3 chemiluminescent immunoassay. Effects on cell proliferation were assessed using tetrazolium-based MTT assays. RESULTS: Median serum VitD level prior to AZA treatment was 32.8 nM (range 11.0-101.5 nM). Patient, disease and treatment characteristics did not differ significantly between the low (≤32.8 nM; n = 29) and high (>32.8 nM; n = 29) VitD group. Estimated probability of 2-year OS in the low versus high VitD group was 14% versus 40% (P < 0.05). In multivariable analysis with OS as endpoint, adverse cytogenetics (HR 2.66, P = 0.03) and VitD (per 10 nM decrease, HR 1.68, P = 0.02) were independent predictors of worse survival. In-vitro treatment of myeloid cell lines with AZA in combination with VitD produced synergistic and additive antiproliferative effects. Addition of nanomolar VitD concentrations to AZA resulted in potentiation of AZA activity. Conversely, combination with the VitD antagonist TEI-9647 resulted in inhibition of AZA activity. CONCLUSIONS: Our study suggests that higher VitD levels were associated with a survival advantage following first-line AZA therapy. Enhanced cytotoxic effects upon combination treatment may contribute to the observed clinical effects. VitD repletion/supplementation during AZA treatment should be explored.

Pinoresinol of olive oil decreases vitamin D intestinal absorption.

Enriching oils, such as olive oil, could be one solution to tackle the worldwide epidemic of vitamin D deficiency and to better fit with omega 3 (DHA) recommendations. However, data regarding the interactions occurring at the intestinal level between vitamin D and phenols from olive oil are scarce. We first determined the effect of polyphenols from a virgin olive oil, and a virgin olive oil enriched with DHA, on vitamin D absorption in rats. We then investigated the effects of 3 main olive oil phenols (oleuropein, hydroxytyrosol and pinoresinol) on vitamin D uptake by Caco-2 cells. The presence of polyphenols in the olive oil supplemented with DHA inhibited vitamin D postprandial response in rats (-25%, p<0.05). Similar results were obtained with a mix of the 3 polyphenols delivered to Caco-2 cells. However, this inhibitory effect was due to the presence of pinoresinol only. As the pinoresinol content can highly vary between olive oils, the present results should be taken into account to formulate an appropriate oil product enriched in vitamin D.

The impact of medication on vitamin D status in older individuals.

OBJECTIVE: Vitamin D deficiency and polypharmacy are common in the elderly. However, knowledge on the associations between the use of specific medicines and serum 25-hydroxyvitamin D (25(OH)D) is limited. The aim of this study was to (better) define the associations between the use of specific medicines and serum 25(OH)D. METHODS: Two different cohorts (1995/1996 and 2002/2003) from the Longitudinal Aging Study Amsterdam (LASA) were used for cross-sectional analyses. LASA is based on an age and sex-stratified random sample of the Dutch older population. Study participants were aged 65-88 years in the first cohort (n = 1301) and 55-65 years in the second cohort (n = 736). Serum 25(OH)D of users of several groups of medicines were compared with levels of non-users using multiple linear regression analysis. RESULTS: Of all participants, 75.4% (first cohort) and 61.1% (second cohort) were using at least one medicine. In both cohorts, the number of medicines was associated with lower serum 25(OH)D. In the first cohort, after adjustment for confounding, users of any kind of medicine, loop diuretics and inhaled corticosteroids (only men) had respectively 4.4 nmol/l (P<0.01), 4.7 nmol/l (P = 0.04) and 7.3 nmol/l (P = 0.02) lower serum 25(OH)D than non-users. In the second cohort, the use of oral antidiabetics, calcium-channel blockers and angiotensin-converting enzyme inhibitors was associated with respectively 7.4 nmol/l (P = 0.04), 7.7 nmol/l (P = 0.01) and 7.6 nmol/l (P<0.01) lower serum 25(OH)D. CONCLUSIONS: These data show that users of several medicines have lower serum 25(OH)D than non-users. Vitamin D supplementation may be considered in patients with chronic use of medicines.

25-hydroxyvitamin D levels and vitamin D deficiency in children with rheumatologic disorders and controls.

OBJECTIVE: To evaluate the prevalence of vitamin D deficiency, as well as factors associated with serum 25-hydroxyvitamin D [25(OH)D] levels, in children attending a pediatric rheumatology clinic, and to determine whether there was a difference in serum 25(OH)D levels and in vitamin D deficiency between children with autoimmune disorders and nonautoimmune conditions. METHODS: Cross-sectional analysis of serum 25(OH)D levels of patients between the ages of 2 and 19 years, seen between November 2008 and October 2009. RESULTS: A total of 254 patients were studied (169 autoimmune disorders, 85 nonautoimmune conditions). The mean age of study patients was 12.3 years; 67% were female and 80% were white. In the autoimmune disorders group, 23% had vitamin D deficiency [serum 25(OH)D < 20 ng/ml], and in the nonautoimmune conditions group 14% were vitamin D deficient. The average level of serum 25(OH)D was 28.6 (± 11) ng/ml (range 2 to 59). Age, ethnicity, body mass index, use of supplements, and season were significantly associated with serum levels of 25(OH)D (all p ≤ 0.02). The OR of patients with autoimmune disorders being vitamin D deficient was 2.3, in relation to patients with nonautoimmune conditions (p = 0.04). CONCLUSION: Twenty percent of patients attending a pediatric rheumatology clinic were vitamin D deficient. Patients with autoimmune disorders were more likely to be vitamin D deficient than patients with nonautoimmune conditions. Screening of serum 25(OH)D levels should be performed for patients with autoimmune disorders.

Low vitamin D among HIV-infected adults: prevalence of and risk factors for low vitamin D Levels in a cohort of HIV-infected adults and comparison to prevalence among adults in the US general population.

BACKGROUND: we explored serum 25-hydroxyvitamin D (25[OH]D) levels and associated factors for insufficiency or deficiency in an adult human immunodeficiency virus (HIV) cohort and compared 25(OH)D levels with those in the general US population. METHODS: using baseline data from the Study to Understand the Natural History of HIV and AIDS in the Era of Effective Therapy (SUN), a prospective, observational cohort study of HIV-infected adults enrolled at 7 HIV specialty clinics in 4 US cities from March 2004 to June 2006, we estimated the prevalence of vitamin D insufficiency or deficiency (defined as 25(OH)D levels <30 ng/mL), standardized by age, race, and sex. Using multiple logistic regression, we examined risk factors for vitamin D insufficiency or deficiency. RESULTS: among 672 SUN participants with baseline serum 25(OH)D determinations who were not receiving vitamin D supplements, 70.3% (95% confidence interval [CI], 68.1%-74.9%) were vitamin D insufficient or deficient, compared with 79.1% (95% CI, 76.7-81.3) of US adults. Factors associated with vitamin D insufficiency or deficiency included black race (adjusted odds ratio [aOR], 4.51; 95% CI, 2.59-7.85), Hispanic ethnicity (aOR, 2.78; 95% CI, 1.31-5.90), higher body mass index (aOR, 1.04; 95% CI, 1.00-1.09), hypertension (aOR, 1.88; 95% CI, 1.10-3.22), lack of exercise (aOR, 3.14; 95% CI, 1.80-5.47), exposure to efavirenz (aOR, 1.98; 95% CI, 1.18-3.34), higher exposure to ultraviolet light (aOR, .78; 95% CI, .71-.86), renal insufficiency (aOR, .55; 95% CI, .36-.83), and exposure to ritonavir (aOR, .56; 95% CI, .35-0.89). CONCLUSIONS: similar to findings in US adults generally, vitamin D insufficiency or deficiency is highly prevalent among HIV-infected adults and is associated with known risk factors. Observed associations of vitamin D levels with renal insufficiency and with use of ritonavir- and efavirenz-containing regimens are consistent with both HIV-related and therapy-mediated alterations in vitamin D metabolism. Clinicians should consider screening all patients for vitamin D insufficiency or deficiency.

Selective inhibitors of vitamin D metabolism--new concepts and perspectives.

BACKGROUND: Levels of active vitamin D (VD) are controlled by synthesis via CYP27B1 and self-induced metabolism by CYP24A1. Unbalanced high CYP24A1 expression due to induction by diverse endogenous compounds and xenobiotics, and amplification found in various tumours, might lead to local VD deficiency, thereby causing/reinforcing disorders. MATERIALS AND METHODS: Using primary human keratinocytes, CYP24A1 expression was examined at the mRNA level by dot-blot and Northern blot hybridization, and at the enzyme activity level by analysing HPLC profiles from incubations with 3H-labelled VD metabolites. RESULTS: We have developed a one-step protocol to screen test compounds for potent inhibition of CYP24A1 along with selectivity over CYP27B1 and adequate metabolic stability. These inhibitors amplified hormone levels and, thereby, its function, indicated by increased CYP24A1 expression. Moreover, they stabilized the expression of a CYP24A1 splice variant, possibly serving as a buffer of VD metabolites. In addition, a low abundant, constitutive 24-hydroxylase, active in the low nanomolar range is described. CONCLUSION: Selective CYP24A1 inhibitors could herald a new era for vitamin D research, as well as for therapeutic application. Inhibitors may be used as single entities or in combination with low doses of potent analogs to prevent and treat various defects of growth and differentiation, and neuro-immuno-endocrine disorders.

[Calcium and vitamin D intake in premenopausal status].

Calcium and vitamin D do an important role in bone metabolism during pregnancy and lactation. It is said that calcium supplementation might have only a transient effect on postpartum bone mineral density. However, as for the Japanese women, calcium intake is insufficient. So pregnant and lactating women should supply calcium in particular for prevention of preeclampsia and osteoporosis.

Regulation of adiposity by dietary calcium.

Recent data from this laboratory demonstrate that increasing adipocyte intracellular Ca(2+) results in a coordinated stimulation of lipogenesis and inhibition of lipolysis. We have also noted that increasing dietary calcium of obese patients for 1 year resulted in a 4.9 kg loss of body fat (P<0.01). Accordingly, we tested the possibility that calcitrophic hormones may act on adipocytes to increase Ca(2+) and lipid metabolism by measuring the effects of 1, 25-(OH)(2)-D in primary cultures of human adipocytes, and found significant, sustained increases in intracellular Ca(2+) and a corresponding marked inhibition of lipolysis (EC(50) approximately 50 pM; P<0.001), suggesting that dietary calcium could reduce adipocyte mass by suppressing 1,25-(OH)(2)-D. To test this hypothesis, we placed transgenic mice expressing the agouti gene specifically in adipocytes on a low (0.4%) Ca/high fat/high sucrose diet either unsupplemented or with 25 or 50% of the protein replaced by non-fat dry milk or supplemented to 1.2% Ca with CaCO(3) for 6 wk. Weight gain and fat pad mass were reduced by 26-39% by the three high calcium diets (P<0.001). The high calcium diets exerted a corresponding 51% inhibition of adipocyte fatty acid synthase expression and activity (P<0.002) and stimulation of lipolysis by 3. 4- to 5.2-fold (P<0.015). This concept of calcium modulation of adiposity was further evaluated epidemiologically in the NHANES III data set. After controlling for energy intake, relative risk of being in the highest quartile of body fat was set to 1.00 for the lowest quartile of Ca intake and was reduced to 0.75, 0.40, and 0.16 for the second, third, and fourth quartiles, respectively, of calcium intake for women (n=380;P<0.0009); a similar inverse relationship was also noted in men (n=7114; P<0.0006). Thus, increasing dietary calcium suppresses adipocyte intracellular Ca(2+) and thereby modulates energy metabolism and attenuates obesity risk.

Interaction of dichloromethylene diphosphonate and vitamin D on bone of thyroparathyroidectomized rats.

Dichloromethylene diphosphonate (Cl2MDP) antagonized the action of vitamin D on bone in thyroparathyroidectomized rats by reducing the metabolic activity of osteoblasts and osteocytes and decreasing the number of osteoclasts. Ultrastructurally, osteoblasts in Cl2MDP-treated rats were interpreted to be less active in bone matrix synthesis. Osteocytes in Cl2MDP-treated rats were interpreted ultrastructurally to be inactive; there was no evidence of bone resorption when compared to osteocytes in rats given vitamin D alone. Abnormal osmiophilic densities in the pericellular bone matrix of rats given vitamin D alone were not present in rats given vitamin D and Cl2MDP. The ultrastructure of osteoclasts was unaltered by Cl2MDT. These cellular changes were associated with a decrease in serum calcium and increase in bone ash and magnesium concentration in rats given high levels (10 mg/kg) of Cl2MDP. Bone adenosine triphosphatase and alkaline phosphatase activities were not affected by Cl2MDP. These results suggest that Cl2MDP may limit the hypercalcemia of hypervitaminosis D by directly inhibiting bone cells in addition to its physicochemical action.