Acute activation of AMP-activated protein kinase prevents H2O2-induced premature senescence in primary human keratinocytes

We investigated the effects of AMPK on H₂O₂-induced premature senescence in primary human keratinocytes. Incubation with 50 µM H₂O₂ for 2 h resulted in premature senescence with characteristic increases in senescence-associated ß-galactosidase (SA-gal) staining 3 days later and no changes in AMPK or p38 MAPK activity. The increase in SA-gal staining was preceded by increases in both p53 phosphorylation (S15) (1 h) and transactivation (6 h) and the abundance of the cyclin inhibitor p21^CIP1 (16 h). Incubation with AICAR or resveratrol, both of which activated AMPK, prevented the H₂O₂-induced increases in both SA-Gal staining and p21 abundance. In addition, AICAR diminished the increase in p53 transactivation. The decreases in SA-Gal expression induced by resveratrol and AICAR were prevented by the pharmacological AMPK inhibitor Compound C, expression of a DN-AMPK or AMPK knock-down with shRNA. Likewise, both knockdown of AMPK and expression of DN-AMPK were sufficient to induce senescence, even in the absence of exogenous H₂O₂. As reported by others, we found that AMPK activation by itself increased p53 phosphorylation at S15 in embryonic fibroblasts (MEF), whereas under the same conditions it decreased p53 phosphorylation in the keratinocytes, human aortic endothelial cells, and human HT1080 fibrosarcoma cells. In conclusion, the results indicate that H₂O₂ at low concentrations causes premature senescence in human keratinocytes by activating p53-p21^CIP1 signaling and that these effects can be prevented by acute AMPK activation and enhanced by AMPK downregulation. They also suggest that this action of AMPK may be cell or context-specific.

Effects of sunlight and diet on vitamin D status of pulmonary tuberculosis patients in Tbilisi, Georgia

OBJECTIVE

Vitamin D deficiency is common in tuberculosis (TB) and this may modulate immune responses. This study investigated vitamin D status in patients with TB and examined the sources of vitamin D in Tbilisi, Georgia.

METHODS

We measured plasma 25-hydroxyvitamin D (25[OH]D) and dietary vitamin D intake in patients with pulmonary TB (n = 85) in Tbilisi, Georgia. To determine the impact of season on vitamin D status, we tested the in vitro conversion of 7-dehydrocholesterol (7-DHC) to previtamin D(3) after sunlight exposure.

RESULTS

In subjects with TB, mean plasma 25(OH)D concentrations were 14.4 ± 7.0 ng/mL, and vitamin D insufficiency (25[OH]D <30 ng/mL) occurred in 97% of subjects. The dietary sources of vitamin D were mainly fish, eggs, and butter. The daily intake was well below recommended daily intakes in subjects with TB (172 ± 196 IU). The conversion of 7-DHC to previtamin D(3) was undetectable from October to March and highest in June and July from 11:00 to 14:00 h.

CONCLUSION

An insufficient vitamin D dietary intake and a limited production of vitamin D from sunlight for most of the year may explain the high prevalence of vitamin D insufficiency in patients with TB in Tbilisi.

C15-functionalized 16-ene-1α,25-dihydroxyvitamin D3 is a new vitamin D analog with unique biological properties

The Δ(16) structure as a vitamin D analog enhanced vitamin D receptor (VDR) binding affinity and induced significant cell differentiation, whereas its relative calcemic activity was reduced compared to 1α,25-dihydroxyvitamin D(3) (1α,25(OH)(2)D(3)). Methodologies available to introduce a double bond at C16-C17 of the D-ring on the seco-steroidal skeleton were limited; therefore, a new synthetic strategy was developed to obtain not only the Δ(16) structure, but also a new C15-functional group. Since C15-functionalization was unprecedented in vitamin D analog studies, the hybrid structure of Δ(16) and the C15-OH group at the D-ring may provide important information on the structure-activity relationship with vitamin D analogs. The synthesized 16-ene-2α-methyl-1α,15α,25-trihydroxyvitamin D(3) showed almost 3-times higher VDR binding affinity and an equipotent level of osteocalcin promoter transactivation activity in human osteosarcoma cells as compared to 1α,25(OH)(2)D(3).

The roles of cytochrome P450 enzymes in prostate cancer development and treatment

The active form of vitamin D, 1α,25-dihydroxyvitamin D [1α,25(OH)(2)D], interacts with vitamin D receptor (VDR) and induces antiproliferative, anti-invasive, proapoptotic and pro-differentiation activities in prostate cancer cells. Three cytochrome P-450 (CYP) hydroxylases are responsible for vitamin D synthesis and degradation, including vitamin D-25-hydroxylase (25-OHase) in the liver, and 25(OH)D-1α-hydroxylase (1α-OHase) or CYP27B1, and 25(OH)D-24-hydroxylase (24-OHase) or CYP24A1 in the kidneys. However, it is now recognized that CYP27B1 and CYP24A1 are also expressed in many tissues and cells, including the prostate. Although at least six CYP enzymes have been identified with 25-OHase activity, the two major ones are CYP27A1 and CYP2R1, and both are expressed in the prostate, with CYP2R1 as the predominate type. This indicates that prostate tissue has the ability to activate and inactivate vitamin D in an autocrine/paracrine fashion. Recent evidence indicates that 25-hydroxyvitamin D [25(OH)D] and its analogs can bind to VDR as agonists, without converting them to 1α,25(OH)(2)D or the corresponding 1α-hydroxylated metabolites, to modulate gene expressions that will lead to cell growth arrest and other antitumor activities. This finding suggests that the circulating levels of 25(OH)D, and the autocrine synthesis of 25(OH)D may play an important role in regulating the growth of prostate cancer. Thus, in addition to 1α,25(OH)(2)D analogs, the presence of CYP2R1, CYP27B1 and CYP24A1 in the prostate suggests that the analogs of vitamin D and 25(OH)D, especially those that are resistant to CYP24A1 degradation, can be developed and used for the prevention and treatment of prostate cancer.

19-Nor-2α-(3-hydroxypropyl)-1α,25-dihydroxyvitamin D3 (MART-10) is a potent cell growth regulator with enhanced chemotherapeutic potency in liver cancer cells

The discovery that the active form of vitamin D, 1α,25-dihydroxyvitamin D [1α,25(OH)(2)D] can modulate cellular proliferation and differentiation of cancer cells has led to its potential application as a chemotherapeutic agent to treat a variety of cancers. However, the use of 1α,25(OH)(2)D is limited due to its lethal side effect of hypercalcemia upon systemic administration. To overcome this drawback, numerous analogs have been synthesized. In this report, we examined the anti-proliferative activity of a new analog, 19-nor-2α-(3-hydroxypropyl)-1α,25(OH)(2)D(3) (MART-10), in HepG2 liver cancer cells, and studied the potential mechanisms mediating this action. We found that MART-10 exhibited approximately 100-fold greater activity than 1α,25(OH)(2)D(3) in inhibiting HepG2 cell proliferation as determined by cell number counting method. MART-10 was also approximately 100-fold more potent than 1α,25(OH)(2)D(3) in the upregulation of p21 and p27, that in turn arrested HepG2 cells at the G(0)/G(1) phase to a greater extent. Given that no active caspase 3 was detected and treatment with 1α,25(OH)(2)D(3) or MART-10 did not further increase the fractions of apoptotic and necrosis cells over the controls, the growth-inhibitory effect of 1α,25(OH)(2)D(3) and MART-10 on HepG2 cells may not involve apoptosis. Overall, our findings suggest that MART-10 is a good candidate as a novel therapeutic regimen against liver cancer. Further pre-clinical studies using animal models and the subsequent human clinical trials are warranted.

Investigating the mechanism for maintaining eucalcemia despite immobility and anuria in the hibernating American black bear (Ursus americanus)

Ursine hibernation uniquely combines prolonged skeletal unloading, anuria, pregnancy, lactation, protein recycling, and lipolysis. This study presents a radiographic and biochemical picture of bone metabolism in free-ranging, female American black bears (Ursus americanus) that were active (spring bears and autumn bears) or hibernating (hibernating bears). Hibernating bears included lactating and non-lactating individuals. We measured serum calcium, albumin, inorganic phosphate, creatinine, bone specific alkaline phosphatase (BSALP), CTX, parathyroid hormone, insulin-like growth factor-I (IGF-l), leptin, 25-hydroxyvitamin D [25(OH)D], 1,25-dihydroxyvitamin D [1,25(OH)(2)D] and sclerostin from 35 to 50 tranquilized hibernating bears and 14 to 35 tranquilized spring bears. We compared metacarpal cortical indices (MCI), measured by digital X-ray radiogrammetry, from 60 hunter-killed autumn bears and 79 tranquilized, hibernating bears. MCI was greater in autumn than winter in younger bears, but showed no seasonal difference in older bears. During hibernation eucalcemia was maintained, BSALP was suppressed, and CTX was in the range expected for anuria. During hibernation 1,25(OH)(2)D was produced despite anuria. 1,25(OH)(2)D and IGF-I were less in hibernating than spring bears. In a quarter of hibernating bears, sclerostin was elevated. Leptin was greater in hibernating than spring bears. In hibernating bears, leptin correlated positively with BSALP in non-lactating bears and with CTX in lactating bears. Taken together the biochemical and radiographic findings indicate that during hibernation, bone turnover was persistent, balanced, and suppressed; bone resorption was lower than expected for an unloaded skeleton; and there was no unloading-induced bone loss. The skeleton appears to perceive that it was loaded when it was actually unloaded during hibernation. However, at the level of sclerostin, the skeleton recognized that it was unloaded. During hibernation leptin appeared anabolic in non-lactating bears and catabolic in lactating bears. We hypothesize that ursine hibernation may represent a natural model in which suppression of the sympathetic nervous system prevents unloading-induced bone loss by influencing leptin's skeletal effects and preventing transmission of loading information.

Substitution at carbon 2 of 19-nor-1α,25-dihydroxyvitamin D3 with 3-hydroxypropyl group generates an analogue with enhanced chemotherapeutic potency in PC-3 prostate cancer cells

The active form of vitamin D(3), 1α,25-dihydroxyvitamin D(3)(1α,25(OH)(2)D(3)), has anti-proliferative and anti-invasive activities in prostate cancer cells. Because of 1α,25(OH)(2)D(3) therapeutic potential in treating cancers, numerous analogues have been synthesized with an attempt to increase anti-proliferative and/or decrease calcemic properties. Among these analogues, 19-nor-1α,25(OH)(2)D(2) while being less calcemic has equivalent potency as 1α,25(OH)(2)D(3) in several in vitro and in vivo systems. We recently showed that 19-nor-2α-(3-hydroxypropyl)-1α,25(OH)(2)D(3) (MART-10) was at least 500-fold and 10-fold more active than 1α,25(OH)(2)D(3) in inhibiting the proliferation of an immortalized normal prostate PZ-HPV-7 cells and the invasion of androgen insensitive PC-3 prostate cancer cells, respectively. In this study, we further investigated the effects of MART-10 and 1α,25(OH)(2)D(3) on the dose- and time-dependent induction of CYP24A1 gene expression in PC-3 prostate cancer cells. We found that MART-10 induced CYP24A1 gene expression at a lower concentration with a longer duration compared to 1α,25(OH)(2)D(3), suggesting that MART-10 is less susceptible to CYP24A1 degradation. Molecular docking model of human CYP24A1 and MART-10 indicates that its side chain is far away from the heme ion and is less likely to be hydroxylated by the enzyme. Furthermore, MART-10 was a more potent inhibitor of PC-3 cell proliferation and invasion compared to 1α,25(OH)(2)D(3). In addition, MART-10 down-regulated matrix metalloproteinase-9 (MMP-9) expression which could be one mechanism whereby MART-10 influences cancer cell invasion. Finally, we observed that subcutaneous administration of MART-10 up-regulated the CYP24A1 mRNA expression in rat kidneys without affecting their plasma calcium levels. Thus, our findings demonstrate that MART-10 is biologically active in vivo and may be an effective vitamin D analogue for clinical trials to treat prostate cancer.

Hepatocellular carcinoma and vitamin D: a review

The non-classical actions of vitamin D, namely antiproliferation, pro-differentiation, pro-apoptosis, anti-inflammation, and immune regulation, have received great attention during the past decade. Increasing evidence from epidemiological studies showing the inverse association between vitamin D status and incidence of many forms of cancer as well as biochemical studies has suggested that vitamin D deficiency may play a role in the cause and progression of these types of cancer. Recently, vitamin D and its analogs have been deemed as potential regimen to treat a variety of cancers alone or in combination with other drugs. Although, the epidemiologic evidence regarding the association of vitamin D and hepatocellular carcinoma (HCC) is still inconclusive, biochemical evidence clearly indicates that HCC cells are responsive to the inhibitory effect of vitamin D and its analogs. In this review, we discuss the current status of HCC and its treatment, the source, metabolism, functions, and the mechanism of actions of vitamin D, and the biochemical studies of vitamin D analogs and their implications in the prevention and treatment of HCC.

Use of a novel vitamin D bioavailability test demonstrates that vitamin D absorption is decreased in patients with quiescent Crohn's disease

BACKGROUND

Vitamin D deficiency is a common problem in patients with Crohn's disease (CD). The aim of this study was to determine the ability of normal subjects and patients with quiescent CD to absorb vitamin D(2) using a novel vitamin D bioavailability test. In addition, we evaluated whether the location of disease or previous surgery had any influence on the bioavailability of vitamin D(2) in CD patients.

METHODS

Ten normal subjects (50% female) and 37 CD patients with quiescent disease (51% female) were included in this study. Subjects who recently received any vitamin D(2) were excluded. The vitamin D bioavailability test was performed in all subjects. After a baseline blood draw, all subjects were then given a single 50,000 IU oral dose of vitamin D(2) in a capsule formulation and had their blood drawn 12 hours later to determine serum vitamin D(2), which reflected their vitamin D(2) absorption capacity.

RESULTS

Forty-two percent and 29% of CD patients were found to be either vitamin D-deficient (25-hydroxyvitamin D [25(OH)D] ≤20 ng/mL] or insufficient [25(OH)D 21-29 ng/mL], respectively. Twelve hours after ingesting 50,000 IU vitamin D(2) , vitamin D(2) levels rose from a baseline of 0.7 ± 0.7 ng/mL (mean ± SEM) to 49.8 ± 3.0 ng/mL in normal subjects. In CD patients, baseline vitamin D(2) levels rose from 0 ng/mL to 34.8 ± 2.8 ng/mL. CD patients had on average a 30% decrease in their ability to absorb vitamin D(2) (P = 0.01). Moreover, we found a wide variability of vitamin D(2) bioavailability in CD patients. Analysis of variance (ANOVA) revealed no statistical difference of vitamin D(2) bioavailability between patients in the CD subgroup stratified by the location of disease, the type of surgery, and receiving or not receiving surgery.

CONCLUSIONS

More than 70% of the patients with quiescent CD were vitamin D-deficient or insufficient. The ability to absorb vitamin D(2) in CD patients is unpredictable and the only way to determine this is to perform a vitamin D bioavailability test. Use of this test may guide clinicians in administering the appropriate therapeutic dose of vitamin D for treating vitamin D deficiency in patients with CD.

Mechanism of the anti-proliferative action of 25-hydroxy-19-nor-vitamin D(3) in human prostate cells

According to the prevailing paradigm, 1α-hydroxylation of 25-hydroxyvitamin D(3) (25(OH)D(3)) and its analogs is a pre-requisite step for their biological effects. We previously reported that 25-hydroxy-19-nor-vitamin D(3) (25(OH)-19-nor-D(3)) had anti-proliferative activity in a cell line, PZ-HPV-7, which was derived from human non-cancerous prostate tissue, and suggested that 25(OH)-19-nor-D(3) acted after 1α-hydroxylation by vitamin D 1α-hydroxylase (CYP27B1). However, metabolic studies of 25(OH)-19-nor-D(3) using recombinant CYP27B1 revealed that 25(OH)-19-nor-D(3) was rarely subjected to 1α-hydroxylation. Therefore, in this report, we attempted to clarify the mechanism of 25(OH)-19-nor-D(3) action in intact cells using PZ-HPV-7 prostate cells. After incubating the cells with 25(OH)-19-nor-D(3), eight metabolites of 24-hydroxylase (CYP24A1) were detected, whereas no products of CYP27B1 including 1α,25-dihydroxy-19-nor-vitamin D(3) (1α,25(OH)(2)-19-nor-D(3)) were found. Furthermore, the time-dependent nuclear translocation of vitamin D receptor (VDR) and the subsequent transactivation of cyp24A1 gene in the presence of 25(OH)-19-nor-D(3) were almost identical as those induced by 1α,25(OH)(2)-19-nor-D(3). These results strongly suggest that 25(OH)-19-nor-D(3) directly binds to VDR as a ligand and transports VDR into the nucleus to induce transcription of cyp24A1 gene. In addition, knock down of cyp27B1 gene did not affect the anti-proliferative activity of 25(OH)-19-nor-D(3), whereas knock down of VDR attenuated the inhibitory effect. Thus, our results clearly demonstrate that the anti-proliferative activity of 25(OH)-19-nor-D(3) is VDR dependent but 1α-hydroxylation independent, suggesting that 25(OH)D(3) analogs such as 25(OH)-19-nor-D(3) could be attractive candidates for anticancer therapy.

Novel vitamin d analogs for prostate cancer therapy

Prostate cells contain specific receptors for 1α,25-dihydroxyvitamin D [1α,25(OH)₂D] or calcitriol, the active form of vitamin D. 1α,25(OH)₂D is known to inhibit the proliferation and invasiveness of prostate cancer cells. These findings support the use of 1α,25(OH)₂D for prostate cancer therapy. However, 1α,25(OH)₂D can cause hypercalcemia, analogs of 1α,25(OH)₂D that are less calcemic but exhibit potent antiproliferative activity would be attractive as therapeutic agents. To accomplish these goals, different strategies, based on metabolism, molecular mechanism of actions, and structural modeling, have been taken to modify the structure of vitamin D molecule with the aims to improve the efficacy and decrease the toxicity of vitamin D to treat different diseases. During the past four decades, over 3,000 analogs have been synthesized. In this paper, we discuss the development and the biological analysis of a unique class of vitamin D analogs with a substitution at the carbon 2 of 19-nor-1α,25(OH)₂D₃ molecule for potential application to the prevention and treatment of prostate cancer as well as other cancers.

Impact of season and diet on vitamin D status of African American and Caucasian children

Seasonal variation of vitamin D status and adequacy of dietary vitamin D and impact of race on maintaining vitamin D sufficiency was assessed in 140 healthy 6- to 12-year-old African American (AA) and Caucasian (C) children residing in Pittsburgh, Pennsylvania during summer and winter. Vitamin D insufficiency was not rare in either group (AA vs C, summer, 17.2% vs 14.3%, nonsignificant; winter, 34.1% vs 32.5%, nonsignificant) despite a mean dietary intake of vitamin D above the American Academy of Pediatrics (AAP) recommended intake (400 IU/d; AA vs C, summer, 421 vs 456 IU/d, nonsignificant; winter, 507 vs 432 IU/d, nonsignificant). Race/season and dietary vitamin D were predictors of serum 25-hydroxyvitamin D [25(OH)D] concentrations. However, dietary vitamin D influenced 25(OH)D only in Caucasians during winter. Current AAP recommended daily intake for vitamin D is inadequate for maintaining vitamin D sufficiency in children.

Vitamin D status, adiposity, and lipids in black American and Caucasian children

OBJECTIVE

The aim of the study was to examine the relationship between vitamin D status, total and abdominal adiposity, and lipids in black and white children.

METHODS

Plasma 25-hydroxyvitamin D [25(OH)D], adiposity [body mass index (BMI), percentage of total body fat, visceral adipose tissue (VAT), sc adipose tissue (SAT)], and fasting lipids were assessed in healthy obese and nonobese 8- to 18-yr-old black and white children.

RESULTS

We studied 237 children (mean ± sd age, 12.7 ± 2.2 yr; 47% black, 47% obese, and 43% male). Mean 25(OH)D concentration for the entire cohort was 19.4 ± 7.4 ng/ml. The majority of the children were vitamin D deficient [25(OH)D < 20 ng/ml; 73% blacks, 40% whites]. Plasma 25(OH)D was associated inversely with BMI, BMI percentile, percentage of total body fat, VAT, and SAT and positively with HDL cholesterol in the entire cohort. VAT was higher in vitamin D-deficient whites, and SAT was higher in vitamin D-deficient blacks compared with their respective vitamin D-nondeficient counterparts. Race, season, pubertal status, and VAT were independent significant predictors of 25(OH)D status.

CONCLUSIONS

In black and white youth examined together, lower levels of 25(OH)D are associated with higher adiposity measures and lower HDL. Furthermore, vitamin D deficiency is associated with higher VAT in whites and greater SAT in blacks. Besides therapeutic interventions to correct the high rates of vitamin D deficiency in youth, benefits of vitamin D optimization on adiposity measures and lipid profile need to be explored.

Vitamin d and pancreatic cancer-an update

The non-classical actions of vitamin D, namely anti-proliferation, pro-differentiation, immune function modulation, and anti-inflammation, have received great attention during the past decade, in particular, the potential of vitamin D analogs alone or in combination with other anticancer agents for the treatment of a variety of cancers. The association between vitamin D status and the higher incidence of many forms of cancer has suggested that vitamin D may play a role in the etiology of these types of cancer. Although it is still controversial whether this association exists for pancreatic cancer, biochemical evidence clearly indicates pancreatic cancer cells are responsive to the inhibitory effect of vitamin D and its analogs. In this review, we discuss briefly the origin and current therapy of pancreatic cancer, the history, source, metabolism and functions of vitamin D, the recent progress in the epidemiological studies of sunlight, and vitamin D status, and biochemical studies of vitamin D analogs in the prevention and treatment of pancreatic cancer.

20-Hydroxyvitamin D2 is a noncalcemic analog of vitamin D with potent antiproliferative and prodifferentiation activities in normal and malignant cells

20-hydroxyvitamin D(2) [20(OH)D(2)] inhibits DNA synthesis in epidermal keratinocytes, melanocytes, and melanoma cells in a dose- and time-dependent manner. This inhibition is dependent on cell type, with keratinocytes and melanoma cells being more sensitive than normal melanocytes. The antiproliferative activity of 20(OH)D(2) is similar to that of 1,25(OH)(2)D(3) and of newly synthesized 1,20(OH)(2)D(2) but significantly higher than that of 25(OH)D(3). 20(OH)D(2) also displays tumorostatic effects. In keratinocytes 20(OH)D(2) inhibits expression of cyclins and stimulates involucrin expression. It also stimulates CYP24 expression, however, to a significantly lower degree than that by 1,25(OH)(2)D(3) or 25(OH)D(3). 20(OH)D(2) is a poor substrate for CYP27B1 with overall catalytic efficiency being 24- and 41-fold lower than for 25(OH)D(3) with the mouse and human enzymes, respectively. No conversion of 20(OH)D(2) to 1,20(OH)(2)D(2) was detected in intact HaCaT keratinocytes. 20(OH)D(2) also demonstrates anti-leukemic activity but with lower potency than 1,25(OH)(2)D(3). The phenotypic effects of 20(OH)D(2) are mediated through interaction with the vitamin D receptor (VDR) as documented by attenuation of cell proliferation after silencing of VDR, by enhancement of the inhibitory effect through stable overexpression of VDR and by the demonstration that 20(OH)D(2) induces time-dependent translocation of VDR from the cytoplasm to the nucleus at a comparable rate to that for 1,25(OH)(2)D(3). In vivo tests show that while 1,25(OH)(2)D(3) at doses as low as 0.8 μg/kg induces calcium deposits in the kidney and heart, 20(OH)D(2) is devoid of such activity even at doses as high as 4 μg/kg. Silencing of CY27B1 in human keratinocytes showed that 20(OH)D(2) does not require its transformation to 1,20(OH)(2)D(2) for its biological activity. Thus 20(OH)D(2) shows cell-type dependent antiproliferative and prodifferentiation activities through activation of VDR, while having no detectable toxic calcemic activity, and is a poor substrate for CYP27B1.

Three-step hydroxylation of vitamin D3 by a genetically engineered CYP105A1: enzymes and catalysis

Our previous studies revealed that the double variant of cytochrome P450 (CYP)105A1, R73V/R84A, has a high ability to convert vitamin D(3) to its biologically active form, 1α,25-dihydroxyvitamin D(3) [1α,25(OH)(2)D(3)], suggesting the possibility for R73V/R84A to produce 1α,25(OH)(2)D(3). Because Actinomycetes, including Streptomyces, exhibit properties that have potential advantages in the synthesis of secondary metabolites of industrial and medical importance, we examined the expression of R73V/R84A in Streptomyces lividans TK23 cells under the control of the tipA promoter. As expected, the metabolites 25-hydroxyvitamin D(3) [25(OH)D(3)] and 1α,25(OH)(2)D(3) were detected in the cell culture of the recombinant S. lividans. A large amount of 1α,25(OH)(2)D(3), the second-step metabolite of vitamin D(3), was observed, although a considerable amount of vitamin D(3) still remained in the culture. In addition, novel polar metabolites 1α,25(R),26(OH)(3)D(3) and 1α,25(S),26(OH)(3)D(3), both of which are known to have high antiproliferative activity and low calcemic activity, were observed at a ratio of 5:1. The crystal structure of the double variant with 1α,25(OH)(2)D(3) and a docking model of 1α,25(OH)(2)D(3) in its active site strongly suggest a hydrogen-bond network including the 1α-hydroxyl group, and several water molecules play an important role in the substrate-binding for 26-hydroxylation. In conclusion, we have demonstrated that R73V/R84A can catalyze hydroxylations at C25, C1 and C26 (C27) positions of vitamin D(3) to produce biologically useful compounds.

Fortification of orange juice with vitamin D(2) or vitamin D(3) is as effective as an oral supplement in maintaining vitamin D status in adults

BACKGROUND

Vitamin D has been added to calcium-fortified orange juice. It is unknown whether vitamin D is as bioavailable from orange juice as it is from supplements.

OBJECTIVES

The objective was to compare the bioavailability of vitamin D(2) and vitamin D(3) from orange juice with that from vitamin D(2) and vitamin D(3) supplements. A secondary aim was to determine which form of vitamin D is more bioavailable in orange juice.

DESIGN

A randomized, placebo-controlled, double-blind study was conducted in healthy adults aged 18-84 y (15-20/group) who received 1000 IU vitamin D(3), 1000 IU vitamin D(2), or placebo in orange juice or capsule for 11 wk at the end of winter.

RESULTS

A total of 64% of subjects began the study deficient in vitamin D (ie, 25-hydroxyvitamin D [25(OH)D]) concentrations <20 ng/mL). Analysis of the area under the curve showed no significant difference in serum 25(OH)D between subjects who consumed vitamin D-fortified orange juice and those who consumed vitamin D supplements (P = 0.084). No significant difference in serum 25(OH)D(3) was observed between subjects who consumed vitamin D(3)-fortified orange juice and vitamin D(3) capsules (P > 0.1). Similarly, no significant difference in serum 25(OH)D(2) was observed between subjects who consumed vitamin D(2)-fortified orange juice and vitamin D(2) capsules (P > 0.1). No significant overall difference in parathyroid hormone concentrations was observed between the groups (P = 0.82).

CONCLUSION

Vitamin D(2) and vitamin D(3) are equally bioavailable in orange juice and capsules.

Low 25-hydroxyvitamin D levels in adolescents: race, season, adiposity, physical activity, and fitness

OBJECTIVES

The objectives were to characterize the vitamin D status of black and white adolescents residing in the southeastern United States (latitude: approximately 33 degrees N) and to investigate relationships with adiposity.

METHODS

Plasma 25-hydroxyvitamin D levels were measured with liquid chromatography-tandem mass spectroscopy for 559 adolescents 14 to 18 years of age (45% black and 49% female). Fat tissues, physical activity, and cardiovascular fitness also were measured.

RESULTS

The overall prevalences of vitamin D insufficiency (<75 nmol/L) and deficiency (< or = 50 nmol/L) were 56.4% and 28.8%, respectively. Black versus white subjects had significantly lower plasma 25-hydroxyvitamin D levels in every season (winter, 35.9 + or - 2.5 vs 77.4 + or - 2.7 nmol/L; spring, 46.4 + or - 3.5 vs 101.3 + or - 3.5 nmol/L; summer, 50.7 + or - 4.0 vs 104.3 + or - 4.0 nmol/L; autumn, 54.4 + or - 4.0 vs 96.8 + or - 2.7 nmol/L). With adjustment for age, gender, race, season, height, and sexual maturation, there were significant inverse correlations between 25-hydroxyvitamin D levels and all adiposity measurements, including BMI percentile (P = .02), waist circumference (P < .01), total fat mass (P < .01), percentage of body fat (P < .01), visceral adipose tissue (P = .015), and subcutaneous abdominal adipose tissue (P = .039). There were significant positive associations between 25-hydroxyvitamin D levels and vigorous physical activity (P < .01) and cardiovascular fitness (P = .025).

CONCLUSIONS

Low vitamin D status is prevalent among adolescents living in a year-round sunny climate, particularly among black youths. The relationships between 25-hydroxyvitamin D levels, adiposity, physical activity, and fitness seem to be present in adolescence.

Hop rho iso-alpha acids, berberine, vitamin D3 and vitamin K1 favorably impact biomarkers of bone turnover in postmenopausal women in a 14-week trial

Osteoporosis is a major health issue facing postmenopausal women. Increased production of pro-inflammatory cytokines resulting from declining estrogen leads to increased bone resorption. Nutrition can have a positive impact on osteoporosis prevention and amelioration. The objective of this study was to investigate the impact of targeted phytochemicals and nutrients essential for bone health on bone turnover markers in healthy postmenopausal women. In this 14-week, single-blinded, 2-arm placebo-controlled pilot study, all women were instructed to consume a modified Mediterranean-style low-glycemic-load diet and to engage in limited aerobic exercise; 17 randomized to the placebo and 16 to the treatment arm (receiving 200 mg hop rho iso-alpha acids, 100 mg berberine sulfate trihydrate, 500 IU vitamin D(3) and 500 microg vitamin K(1), twice daily). Thirty-two women completed the study. Baseline nutrient intake did not differ between arms. At 14 weeks, the treatment arm exhibited an estimated 31% mean reduction (P = 0.02) in serum osteocalcin (a marker of bone turnover), whereas the placebo arm exhibited a 19% increase (P = 0.03) compared to baseline. Serum 25-hydroxyvitamin D (25(OH)D) increased by 13% (P = 0.24) in the treatment arm and decreased by 25% (P < 0.01) in the placebo arm. The between-arm differences for OC and 25(OH)D were statistically significant. Serum IGF-I was increased in both arms, but the increase was more significant in the treatment arm at 14 weeks (P < 0.01). Treatment with hop rho iso-alpha acids, berberine sulfate trihydrate, vitamin D(3) and vitamin K(1) produced a more favorable bone biomarker profile that supports a healthy bone metabolism.

Widespread vitamin D deficiency in urban Massachusetts newborns and their mothers

OBJECTIVE

To determine vitamin D status and associated factors in a cohort of newly delivered infants and their mothers in Boston, Massachusetts.

PATIENTS AND METHODS

Enrollment in this cross-sectional study took place from 2005 to 2007 in an urban Boston teaching hospital with 2500 births per year. A questionnaire and medical-record data were used to identify variables that are potentially associated with vitamin D deficiency (25-hydroxyvitamin D [25(OH)D] < 20 ng/mL). Infant and maternal blood was obtained by venipuncture within 72 hours of birth. The main outcome measure was infant and maternal 25(OH)D status, assessed by competitive protein binding.

RESULTS

We enrolled 459 healthy mother/infant pairs. After subsequent exclusions, analyses were performed on 376 newborns and 433 women. The median infant 25(OH)D level was 17.2 ng/mL (95% confidence interval [CI]: 16.0-18.8; range: <5.0 to 60.8 ng/mL). The median maternal 25(OH)D level was 24.8 ng/mL (95% CI: 23.2-25.8; range: <5.0 to 79.2 ng/mL). Overall, 58.0% of the infants and 35.8% of the mothers were vitamin D deficient (25[OH]D < 20 ng/mL); 38.0% of the infants and 23.1% of the mothers were severely deficient (25[OH]D < 15 ng/mL). Risk factors for infant vitamin D deficiency included maternal deficiency (adjusted odds ratio [aOR]: 5.28 [95% CI: 2.90-9.62]), winter birth (aOR: 3.86 [95% CI: 1.74-8.55]), black race (aOR: 3.36 [95% CI: 1.37-8.25]), and a maternal BMI of >/=35 (aOR: 2.78 [95% CI: 1.18-6.55]). Maternal prenatal-vitamin use throughout the second and third trimesters was protective against infant deficiency (aOR: 0.30 [95% CI: 0.16-0.56]). Similarly, prenatal-vitamin use of > or =5 times per week in the third trimester was protective for mothers (aOR: 0.37 [95% CI: 0.20-0.69]). Despite this, >30% of the women who took prenatal vitamins were still vitamin D deficient at the time of birth.

CONCLUSIONS

A high proportion of infants and their mothers in New England were vitamin D deficient. Prenatal vitamins may not contain enough vitamin D to ensure replete status at the time of birth.

Products of vitamin D3 or 7-dehydrocholesterol metabolism by cytochrome P450scc show anti-leukemia effects, having low or absent calcemic activity

Background

Cytochrome P450scc metabolizes vitamin D3 to 20-hydroxyvitamin D3 (20(OH)D3) and 20,23(OH)₂D3, as well as 1-hydroxyvitamin D3 to 1α,20-dihydroxyvitamin D3 (1,20(OH)₂D3). It also cleaves the side chain of 7-dehydrocholesterol producing 7-dehydropregnenolone (7DHP), which can be transformed to 20(OH)7DHP. UVB induces transformation of the steroidal 5,7-dienes to pregnacalciferol (pD) and a lumisterol-like compounds (pL).

Methods and Findings

To define the biological significance of these P450scc-initiated pathways, we tested the effects of their 5,7-diene precursors and secosteroidal products on leukemia cell differentiation and proliferation in comparison to 1α,25-dihydroxyvitamin D3 (1,25(OH)₂D3). These secosteroids inhibited proliferation and induced erythroid differentiation of K562 human chronic myeloid and MEL mouse leukemia cells with 20(OH)D3 and 20,23(OH)₂D3 being either equipotent or slightly less potent than 1,25(OH)₂D3, while 1,20(OH)₂D3, pD and pL compounds were slightly or moderately less potent. The compounds also inhibited proliferation and induced monocytic differentiation of HL-60 promyelocytic and U937 promonocytic human leukemia cells. Among them 1,25(OH)₂D3 was the most potent, 20(OH)D3, 20,23(OH)₂D3 and 1,20(OH)₂D3 were less active, and pD and pL compounds were the least potent. Since it had been previously proven that secosteroids without the side chain (pD) have no effect on systemic calcium levels we performed additional testing in rats and found that 20(OH)D3 had no calcemic activity at concentration as high as 1 µg/kg, whereas, 1,20(OH)₂D3 was slightly to moderately calcemic and 1,25(OH)₂D3 had strong calcemic activity.

Conclusions

We identified novel secosteroids that are excellent candidates for anti-leukemia therapy with 20(OH)D3 deserving special attention because of its relatively high potency and lack of calcemic activity.

Proapoptotic fibronectin fragment induces the degradation of ubiquitinated p53 via proteasomes in periodontal ligament cells

BACKGROUND AND OBJECTIVE

The extracellular matrix (ECM) plays a key role in signaling necessary for tissue remodeling and cell survival. However, signals from the ECM altered by disease, e.g. inflammatory diseases such as periodontitis and arthritis, may lead to apoptosis or programmed cell death of resident cells. Previously, we found that a disease-associated fibronectin fragment triggers apoptosis of primary human periodontal ligament cells via a novel apoptotic pathway in which the tumor suppressor, p53, is transcriptionally downregulated.

MATERIAL AND METHODS

We used immunofluorescence, transfection assays, western blotting and ELISAs to show that p53 is degraded by a proteasomal pathway in response to a proapoptotic disease-associated fibronectin fragment.

RESULTS

We found that in these apoptotic conditions, p53 is further downregulated by post-translational ubiquitination and subsequent targeting to proteasomes for degradation. Pretreatment of cells with the proteasomal inhibitors MG132 and lactacystin rescued the cells from apoptosis. The p53 levels in cells transfected with ubiquitin small interfering RNA were resistant to degradation induced by the proapoptotic fibronectin fragment, showing that ubiquitination is important for the proapoptotic fibronectin fragment-induced degradation of p53.

CONCLUSION

These data show that a proapoptotic fibronectin matrix induces ubiquitination and degradation of p53 in the proteasome as part of a novel mechanism of apoptosis associated with inflammatory diseases.

Alterations in Lipids and Adipocyte Hormones in Female-to-Male Transsexuals

Testosterone therapy in men and women results in decreased high-density lipoprotein cholesterol (HDL) and increased low-density lipoprotein cholesterol (LDL). We sought to determine whether testosterone therapy has this same effect on lipid parameters and adipocyte hormones in female-to-male (FTM) transsexuals. Twelve FTM transsexuals provided a fasting lipid profile including serum total cholesterol, HDL, LDL, and triglycerides prior to and after 1 year of testosterone therapy (testosterone enanthate or cypionate 50-125 mg IM every two weeks). Subjects experienced a significant decrease in mean serum HDL (52 +/- 11 to 40 +/- 7 mg/dL) (P < .001). The mean LDL (P = .316), triglyceride (P = .910), and total cholesterol (P = .769) levels remained unchanged. In a subset of subjects, we measured serum leptin levels which were reduced by 25% but did not reach statistical significance (P = .181) while resistin levels remained unchanged. We conclude that testosterone therapy in FTM transsexuals can promote an increased atherogenic lipid profile by lowering HDL and possibly reduce serum leptin levels. However, long-term studies are needed to determine whether decreases in HDL result in adverse cardiovascular outcomes.

First Report of Capsicum chlorosis virus Infecting Amaryllis and Blood Lily in Taiwan

Capsicum chlorosis virus (CaCV), a thrips-transmitted, tentative species in the genus Tospovirus, family Bunyaviridae, was first identified in solanaceous crops, but also infects several ornamental crops such as orchid (4), gloxinia (3), and calla lily (1). From 2005 to 2007, virus-like yellow ringspots were observed on the leaves of amaryllis (Hippeastrum hybridum Hort.) and blood lily (Haemanthus multiflorus Martyn.) plants cultured in screenhouses and a private garden, respectively. Three of several hundred amaryllis plants in screenhouses from two places were observed as showing yellow ringspot symptoms and one of six blood lily plants was observed as showing similar yellow ringspot symptoms. Sap extracts from symptomatic leaves were inoculated to Chenopodium quinoa Willd. and the resulting local lesions were passaged three successive times to C. quinoa for virus isolation. Using the tospovirus genus-specific primers gL3637 and gL4435c designed from the conserved region in the L RNA (2), DNA fragments of the expected size of 800 bp were amplified by reverse transcription (RT)-PCR from field samples and local lesions from C. quinoa. Extracts from the diseased plants and local lesions of C. quinoa reacted strongly with antiserum against the nucleocapsid (N) protein of CaCV in ELISA and western blotting. To confirm the identity of this virus, we amplified the N gene from three amaryllis and one blood lily source using primer pair WN2328 and WN3534 designed from the S RNA of Watermelon silver mottle virus (1), and these products were cloned and sequenced. The sequence from each virus isolate was determined from three independent clones. The nucleotide and deduced amino acid sequences of N genes for the blood lily isolate (GenBank Accession No. EF101344) and three amaryllis isolates (GenBank Accession Nos. EF101343, EF137177, and FJ185170) had identities greater than 97% with that of a CaCV isolate infecting Capsicum spp. found in Australia (GenBank Accession No. AY036057). Phylogenetic analysis using maximum parsimony showed that these sequences clustered with CaCV. These results show that the virus identified from amaryllis and blood lily that were expressing yellow ringspot symptoms are isolates of CaCV. To our knowledge, this is the first report of CaCV naturally infecting amaryllis and blood lily and it could become an important threat to ornamental production in Taiwan. References: (1) C. C. Chen et al. Plant Dis. 91:1201, 2007. (2) F. H. Chu et al. Phytopathology 91:361, 2001. (3) H. T. Hsu et al. J. Gen. Plant Pathol. 66:167, 2000. (4) Y. X. Zheng et al. Eur. J. Plant Pathol. 120:199, 2008.

Fish oil enhances the antiproliferative effect of 1alpha,25-dihydroxyvitamin D3 on liver cancer cells

BACKGROUND

Laboratory and epidemiological studies have indicated that 1alpha,25-dihydroxyvitamin D3 [1alpha,25(OH)2D3] and dietary omega 3 (omega3)-polyunsaturated fatty acids (PUFAs) are capable of inhibiting the proliferation of various cancer cells.

MATERIALS AND METHODS

Human hepatoblastoma cells (HepG2) were treated with 1alpha,25(OH)2D3 and fish oil alone and in combination. Cell proliferation was measured either by the uptake of [3H]-thymidine into DNA or by counting the cell numbers using a hemocytometer.

RESULTS

The HepG2 cell proliferation was inhibited by 1alpha,25(OH)2D3 and fish oil in a dose-dependent manner. The lowest effective concentration of 1alpha,25(OH)2D3 was 10(-7) M and 10(-8) M using the [3H]-thymidine incorporation method and the cell counting method, respectively. Fish oil also caused a significant inhibition in HepG2 cell proliferation at 25 microg/mL. When HepG2 cells were treated with 1alpha,25(OH)2D3 in combination with fish oil, it was found that fish oil increased the antiproliferative effect of 1alpha,25(OH)2D3 on HepG2 cell growth compared to treatment with 1alpha,25(OH)2D3 alone.

CONCLUSION

1alpha,25(OH)2D3 could be used to treat hepatocellular carcinoma (HCC). However, the major side-effect of hypercalcemia limits its use. An enhanced 1alpha,25(OH)2D3-induced inhibition of HepG2 cell proliferation in the presence of PUFAs in the form of fish oil suggests that a lower concentration of 1alpha,25(OH)2D3 could be used to treat hepatocellular carcinoma in the presence of PUFAs to decrease the risk of hypercalcemia caused by high concentrations of 1alpha,25(OH)2D3.

Synthesis and biological activities of 14-epi-MART-10 and 14-epi-MART-11: implications for cancer and osteoporosis treatment

The 14-epimer of MART-10, namely 14-epi-MART-10 (14-epi-2alpha-(3-hydroxypropyl)-1alpha,25-dihydroxy-19-norvitamin D3) and its 2-epimeric analog (14-epi-MART-11) were efficiently synthesized using the Julia coupling reaction to connect between the C5 and C6 positions (steroid numbering). An A-ring precursor was prepared from (-)-quinic acid as shown in the previous MART-10 synthesis. The novel 14-epi-CD-ring coupling partner with an elongated two carbon unit as a sulfone was synthesized from 14-epi-25-hydroxy Grundmann's ketone in good yield. The subsequent coupling reaction followed by a deprotection step afforded a mixture of 14-epi-MART-10 and 14-epi-MART-11 in 40% yield. To separate 14-epi-MART-10 and 14-epi-MART-11, each primary hydroxyl group was esterified with a pivaloyl group and the resulting pivalates 2alpha and 2beta were separated by high performance liquid chromatography. After the separation, the C2-stereochemistry of each (2alpha or 2beta) was determined by 1H NMR (nuclear magnetic resonance) studies including NOE (nuclear Overhauser effect) experiments. The pivaloyl group was removed under basic conditions to obtain the target molecules of 14-epi-MART-10 and 14-epi-MART-11, respectively. The VDR (vitamin D receptor)-binding affinity, HL-60 (human promyelocytic leukemia) cell differentiation activity, antiproliferative activity in PZ-HPV-7 (immortalized normal prostate) cells and transactivation activity of the osteocalcin promoter in HOS (human osteoblast cell line) cells (serum-free conditions) were investigated. In addition, the effects on bone mineral density (BMD) and the blood and urine calcium concentrations of ovariectomized (OVX) rats were examined. 14-epi-MART-10 has much greater antiproliferative and cell differentiation activities compared to 1alpha,25-dihydroxyvitamin D3 (1alpha,25(OH)2D3).

Relation of body fat indexes to vitamin D status and deficiency among obese adolescents

BACKGROUND

Data on the relation between vitamin D status and body fat indexes in adolescence are lacking.

OBJECTIVE

The objective was to identify factors associated with vitamin D status and deficiency in obese adolescents to further evaluate the relation of body fat indexes to vitamin D status and deficiency.

DESIGN

Data from 58 obese adolescents were obtained. Visceral adipose tissue (VAT) was measured by computed tomography. Dual-energy X-ray absorptiometry was used to measure total bone mineral content, bone mineral density, body fat mass (FM), and lean mass. Relative measures of body fat were calculated. Blood tests included measurements of 25-hydroxyvitamin D [25(OH)D], parathyroid hormone (PTH), osteocalcin, type I collagen C-telopeptide, hormones, and metabolic factors. Vitamin D deficiency was defined as 25(OH)D < 20 ng/mL. PTH elevation was defined as PTH > 65 ng/mL.

RESULTS

The mean (+/-SD) age of the adolescents was 14.9 +/- 1.4 y; 38 (66%) were female, and 8 (14%) were black. The mean (+/-SD) body mass index (in kg/m(2)) was 36 +/- 5, FM was 40.0 +/- 5.5%, and VAT was 12.4 +/- 4.3%. Seventeen of the adolescents were vitamin D deficient, but none had elevated PTH concentrations. Bone mineral content and bone mineral density were within 2 SDs of national standards. In a multivariate analysis, 25(OH)D decreased by 0.46 +/- 0.22 ng/mL per 1% increment in FM (beta +/- SE, P = 0.05), whereas PTH decreased by 0.78 +/- 0.29 pg/mL per 1% increment in VAT (P = 0.01).

CONCLUSIONS

To the best of our knowledge, our results show for the first time that obese adolescents with 25(OH)D deficiency, but without elevated PTH concentrations, have a bone mass within the range of national standards (+/-2 SD). The findings provide initial evidence that the distribution of fat may be associated with vitamin D status, but this relation may be dependent on metabolic factors. This study was registered at www.clinicaltrials.gov as NCT00209482, NCT00120146.

Evaluation of 19-nor-2alpha-(3-hydroxypropyl)-1alpha,25-dihydroxyvitamin D3 as a therapeutic agent for androgen-dependent prostate cancer

The high incidence of prostate cancer and lack of an effective, long-term treatment for metastatic disease highlights the need for more potent non-calcemic vitamin D analogs as potential alternative or combinational prostate cancer therapies. Among the analogs, 19-nor-1alpha,25-dihydroxyvitamin D2 (19-nor-1alpha,25(OH)2D2) known as paricalcitol or Zempler, has less calcemic effects and an equipotential activity as 1alpha,25-dihydroxyvitamin D3 (1alpha,25(OH)2D3) in several in vivo and in vitro systems. It was recently demonstrated that a modified analog of paricalcitol, 19-nor-2alpha-(3-hydroxypropyl)-1alpha,25-dihydroxyvitamin D3 (MART-10) compared to 1alpha,25(OH)2D3 was more effective in inhibiting proliferation of an immortalized normal prostate cell line (PZ-HPV-7) (1,000-fold) and invasion of PC-3 prostate cancer cells (10-fold). In this study, the effects of MART-10 and 1alpha,25(OH)2D3 on proliferation, vitamin D receptor transactivation, vitamin D-binding protein (DBP) binding, CYP24A1 (24-OHase) substrate hydroxylation kinetics, and induction of CYP24A1 gene expression were compared in an androgen-dependent prostate cancer cell model, LNCaP. The results demonstrated that MART-10 was 1,000-fold more active than 1alpha,25(OH)2D3 in inhibiting LNCaP cell proliferation. MART-10 was more active than 1alpha,25(OH)2D3 in up-regulating a vitamin D receptor-responsive Luciferase construct and inducing CYP24A1 gene expression in LNCaP prostate cancer cells. In addition, MART-10 has a lower affinity for DBP and less substrate degradation by CYP24A1 compared to 1alpha,25(OH)2D3, indicating that MART-10 has more bioavailability and a longer half-life. Thus, these data suggest that MART-10 may be a potential candidate as a therapeutic agent for prostate cancer, especially for patients who fail in conventional therapies.

Vitamin D for the prevention and treatment of pancreatic cancer

Pancreatic cancer is ranked fifth among cancer-related deaths worldwide with a 5-year survival rate of less than 5%. Currently, surgery is the only effective therapy. However, most patients are diagnosed in the late stage and are not suitable for receiving curative surgery. Moreover, pancreatic cancer doesn’t respond well to traditional chemotherapy and radiotherapy, leaving little effective treatment for advanced pancreatic cancer cases. 1α,25-dihydroxyvitamin D₃ [1α,25(OH)₂D₃], the biologically active form of vitamin D₃, was originally identified during studies of calcium and bone metabolism, though it is now recognized that it exerts biological effects in almost every tissue in the body. Abundant evidence has shown that 1α,25(OH)₂D₃ has antiproliferative, apoptotic, pro-differentiation and antiangiogensis effects in many types of cancer cells in vivo and in vitro, including breast, prostate, and colon. Similarly, the antitumor growth effect of 1α,25(OH)₂D₃ on pancreatic cells has been demonstrated. The clinical use of 1α,25(OH)₂D₃ is impeded by the lethal side effects of hypercalcemia and hypercalciuria. Therefore, 1α,25(OH)₂D₃ analogs, which are either equipotent or more potent than 1α,25(OH)₂D₃ in inhibiting tumor cell growth but with fewer hypercalcemic and hypercalciuric side effects, have been developed for the treatment of different cancers. Recently, a pre-clinical study demonstrated that a less calcemic analog of 1α,25(OH)₂D₃, 19-nor-1α,25(OH)₂D₂ (Paricalcitol), is effective in inhibiting tumor growth in vitro and in vivo, via upregulation of p21 and p27 tumor suppressor genes. Studies on the anti-tumor effects of a more potent analog of Paricalcitol are underway. 1α,25(OH)₂D₃ and its analogs are potentially attractive novel therapies for pancreatic cancer.

Panther chameleons, Furcifer pardalis, behaviorally regulate optimal exposure to UV depending on dietary vitamin D3 status

Reptiles may bask for reasons other than thermoregulation. One alternative is to regulate homeostasis of vitamin D(3), a hormone essential to the health of many reptiles. Maintenance of vitamin D(3) homeostasis requires either regulation of exposure to ultraviolet radiation (UV) or ingested vitamin D(3). However, the prey items of most vertebrates tend to be low in vitamin D(3). Thus, basking may be the primary opportunity for vitamin D(3) regulation. We tested the hypothesis that panther chameleons (Furcifer pardalis) behaviorally regulate exposure to UV in natural sunlight with high precision, accuracy, and effectiveness. Panther chameleons with low dietary vitamin D(3) intake significantly increased exposure to UV in natural sunlight compared to those with high dietary vitamin D(3) intake. All lizards fed low dietary vitamin D(3) regulated within optimal UV levels with extreme effectiveness (ability to regulate within optimal UV levels relative to available UV). Chameleons of both dietary treatments regulated UV exposure with great precision, exhibiting little variation among individuals within treatments. Our results add to a growing body of literature that empirically demonstrates the importance of basking for nonthermoregulatory purposes and, more specifically, as an integral mechanism for the regulation of a vital hormone, vitamin D(3).

Association between vitamin D deficiency and primary cesarean section

BACKGROUND

At the turn of the 20th century, women commonly died in childbirth due to rachitic pelvis. Although rickets virtually disappeared with the discovery of the hormone vitamin D, recent reports suggest vitamin D deficiency is widespread in industrialized nations. Poor muscular performance is an established symptom of vitamin D deficiency. The current U.S. cesarean birth rate is at an all-time high of 30.2%. We analyzed the relationship between maternal serum 25-hydroxyvitamin D [25(OH)D] status, and prevalence of primary cesarean section.

METHODS

Between 2005 and 2007, we measured maternal and infant serum 25(OH)D at birth and abstracted demographic and medical data from the maternal medical record at an urban teaching hospital (Boston, MA) with 2500 births per year. We enrolled 253 women, of whom 43 (17%) had a primary cesarean.

RESULTS

There was an inverse association with having a cesarean section and serum 25(OH)D levels. We found that 28% of women with serum 25(OH)D less than 37.5 nmol/liter had a cesarean section, compared with only 14% of women with 25(OH)D 37.5nmol/liter or greater (P = 0.012). In multivariable logistic regression analysis controlling for race, age, education level, insurance status, and alcohol use, women with 25(OH)D less than 37.5 nmol/liter were almost 4 times as likely to have a cesarean than women with 25(OH)D 37.5 nmol/liter or greater (adjusted odds ratio 3.84; 95% confidence interval 1.71 to 8.62).

CONCLUSION

Vitamin D deficiency was associated with increased odds of primary cesarean section.

Serum 25-hydroxyvitamin D and bone mineral density among Hispanic men

There are few data on the skeletal health of Hispanic men. We observed differences in vitamin D deficiency and low BMD between Hispanic ethnic subgroups that persisted with adjustment for risk factors. Our data indicate a substantial burden of low BMD and vitamin D deficiency among Hispanic men.

INTRODUCTION

Disparities within ethnic groups are generally ignored, but in evolving populations they may have implications for public health. We examined ethnic variation in serum 25-hydroxyvitamin D [25(OH)D] and bone mineral density (BMD) among Hispanic American men.

METHODS

Three hundred and fifty-eight Hispanic males 30 to 79 years of age were studied. Logistic regression models assessed variation in odds of vitamin D deficiency (<20 ng/mL) and low BMD (T-score<-1) by ethnicity, with and without adjustment for risk factors (age, smoking, occupation, physical activity, body mass index, and sunlight exposure).

RESULTS

Vitamin D deficiency was most common among Puerto Rican (26%), compared with Dominican (21%), Central American (11%), and South American (9%) men. Percentages with low BMD were: South American (44%), Puerto Rican (34%), Dominican (29%), and Central American (23%). Adjustment for age and risk factors failed to account for Hispanic subgroup differences in vitamin D deficiency and low BMD. Population estimates indicate a substantial burden of low BMD and vitamin D deficiency among Hispanic men.

CONCLUSIONS

Our findings underscore the importance of examining the skeletal health of Hispanic subgroups, and suggest that a considerable number of Hispanic men may be at elevated risk of fracture and vitamin D deficiency.

Standard multivitamin supplementation does not improve vitamin D insufficiency after burns

Children suffering severe burns develop progressive vitamin D deficiency because of inability of burned skin to produce normal quantities of vitamin D(3) and lack of vitamin D supplementation on discharge. Our study was designed to determine whether a daily supplement of a standard multivitamin tablet containing vitamin D(2) 400 IU (10 microg) for 6 months would raise serum levels of 25-hydroxyvitamin D [25(OH)D] to normal. We recruited eight burned children, ages 5-18, whose families were deemed reliable by the research staff. These children were given a daily multivitamin tablet in the hospital for 3 months in the presence of a member of the research staff and then given the remainder at home. At 6 months, the subjects returned for measurements of serum levels of 25(OH)D,1,25-dihydroxyvitamin D [1,25(OH)(2)D], intact parathyroid hormone (iPTH), Ca, P, albumin, and total protein as well as bone mass by dual energy X-ray absorptiometry. Serum 25(OH)D levels were compared to a group of seven age-matched burned children studied at an earlier date without the vitamin supplement but with the same method of determination of 25(OH)D at 6 months post-burn. In addition, the chewable vitamins were analyzed for vitamin D(2) content by high performance liquid chromatography. Serum concentration of 25(OH)D was 21 +/- 11(SD) ng/ml (sufficient range 30-100) with only one of the eight children having a value in the sufficient range. In comparison, the unsupplemented burn patients had mean serum 25(OH)D level of 16 +/- 7, P = 0.33 versus supplemented. Serum levels of 1,25(OH)(2)D, iPTH, Ca, P, albumin, and total protein were all normal in the supplemented group. Vitamin D(2) content of the chewable tablets after being saponified and extracted was 460 +/- 20 IU. Bone mineral content of the total body and lumbar spine, as well as lumbar spine bone density, failed to increase as expected in the supplemented group. No correlations were found between serum 25(OH)D levels and age, length of stay, percent body surface area burn or third-degree burn. Supplementation of burned children with a standard multivitamin tablet stated to contain 400 IU of vitamin D(2) failed to correct the vitamin D insufficiency.

Plasma 25-hydroxyvitamin D levels in young children undergoing placement of tympanostomy tubes

OBJECTIVES

We report the plasma 25-hydroxyvitamin D [25(OH)D] levels of 16 young children who were undergoing ambulatory surgery for placement of tympanostomy tubes.

METHODS

We previously obtained blood samples from young children who were undergoing ambulatory surgery and reported that they had lower blood levels than adults of eicosapentaenoic acid (an omega-3 fatty acid), vitamin A, and selenium. Plasma frozen continuously at -80 degrees C was available from 16 subjects who were undergoing placement of tympanostomy tubes.

RESULTS

The mean (+/- SD) age of the patients was 3.7 +/- 1.6 years (median, 2.9 years; range, 1.9 to 7.4 years). Sixty-two percent were male; half were white, and half were Hispanic. Sixty-two percent were private patients; the parents reported that half were taking vitamin supplements. None had a history of rickets. None had 25(OH)D levels less than 10 ng/mL; 50% had 25(OH)D levels less than 20 ng/mL (deficient in adults); another 31% had levels from 21 to 29 ng/mL (insufficient in adults).

CONCLUSIONS

Vitamin D is essential for the production of endogenous antimicrobial peptides, and has been linked to seasonal, epidemic influenza A. However, the level of 25(OH)D needed to prevent infection with various human pathogens has not been defined. In view of increasing bacterial resistance and emerging new pathogens, further research on the relationship of infection to 25(OH)D and other nutritional factors is warranted.

Spectral domain optical coherence tomography for quantitative evaluation of drusen and associated structural changes in non-neovascular age-related macular degeneration

Background/aims:

To demonstrate how spectral domain optical coherence tomography (SDOCT) can better evaluate drusen and associated anatomical changes in eyes with non-neovascular age-related macular degeneration (AMD) compared with time domain optical coherence tomography (TDOCT).

Methods:

Images were obtained from three eyes of three patients with AMD using an experimental SDOCT system. Both a titanium–sapphire (Ti:sapphire) laser and a superluminescent diode (SLD) were used as a broadband light source to achieve cross-sectional images of the retina. A qualitative and quantitative analysis was performed for structural changes associated with non-neovascular AMD. An automated algorithm was developed to analyse drusen area and volume from SDOCT images. TDOCT was performed using the fast macular scan (StratusOCT, Carl Zeiss Meditec, Dublin, California).

Results:

SDOCT images can demonstrate structural changes associated with non-neovascular AMD. A new SDOCT algorithm can determine drusen area, drusen volume and proportion of drusen.

Conclusions:

With new algorithms to determine drusen area and volume and its unprecedented simultaneous ultra-high speed ultra-high resolution imaging, SDOCT can improve the evaluation of structural abnormalities in non-neovascular AMD.

25-Hydroxyvitamin D-1 alpha-hydroxylase (CYP27B1) is a new class of tumor suppressor in the prostate

The active form of vitamin D, 1alpha,25-dihydroxyvitamin D (1alpha,25(OH)2D), inhibits proliferation and induces the differentiation of prostate cells in culture, attenuates tumor growth in animal models, and decreases prostate specific antigen (PSA) levels in prostate cancer patients. The enzymes that are responsible for the activation of vitamin D to 1alpha,25(OH)2D include vitamin D-25-hydroxylase (25-OHase) and 25-hydroxyvitamin D-1alpha-hydroxylase (1alpha-OHase or CYP27BJ) and are present in cultured prostate cells. The demonstration that a differential expression of 1alpha-OHase between noncarcinogenic and carcinogenic prostate cells and the ability of epidermal growth factor (EGF) to up-regulate 1alpha-OHase promoter activity in the noncarcinogenic, not the carcinogenic prostate cells suggested that a dysregulation of 1alpha-OHase in cancer cells may lead to the aberrant growth of prostate cancer cells. Thus, the 1alpha-OHase gene is a tumor suppressor gene responsible for the normal regulation of prostate cell growth.

Prostate 25-hydroxyvitamin D-1alpha-hydroxylase is up-regulated by suberoylanilide hydroxamic acid (SAHA), a histone deacetylase inhibitor

Prostatic 25-hydroxyvitamin D-1alpha-hydroxylase (1alpha-OHase) is up-regulated by epidermal growth factor (EGF) and down-regulated by 1alpha,25-dihydroxyvitamin D [1alpha,25(OH)2D] at the promoter level in an autocrine/paracrine fashion, suggesting that local production of 1alpha,25(OH)2D could provide an important cell growth regulatory mechanism. Gene expressions depend on the acetylation status of the histone tails of chromatin, which is regulated by histone acetyltransferases and histone deacetylases (HDAC). A number of HDAC inhibitors, including suberolylanilide hydroxamic acid (SAHA), can inhibit tumor growth in vitro and in vivo. Moreover, SAHA increases the expression of genes which modulate cell cycle progression, tumor suppression, differentiation and apoptosis. Therefore, whether SAHA might also regulate 1alpha-OHase activity in PZ-HPV-7 prostate cells was investigated. SAHA at 10 microM up-regulated 1alpha-OHase activity approximately two-fold as analyzed by the formation of 3H-1alpha,25(OH)2D3 from 3H-25-hydroxyvitamin D3 using high performance liquid chromatography. SAHA (10 microM) also stimulated 1alpha-OHase mRNA expression as measured by real-time polymerase chair reaction, and promoter activity determined by luciferase reporter gene assay. The findings suggest that another important action of SAHA may be to up-regulate the expression of the 1alpha-OHase gene that controls the synthesis of 1alpha,25(OH)2D which in turn regulates prostate growth and differentiation in an autocrine/paracrine fashion.

25-Hydroxyvitamin D, cholesterol, and ultraviolet irradiation

Vitamin D deficiency may have implications for cardiovascular health. The purpose of this study was to determine the relationship of 25-hydroxyvitamin D (25[OH]D) to cholesterol and lipoprotein particles and to determine whether increasing 25(OH)D through ultraviolet (UV) irradiation impacted on these parameters in healthy young men and women. This was a randomized trial of 51 adults exposed to suberythemal doses of whole-body irradiation using UV lamps that emitted UV-A and UV-B radiation, compared with a control group, twice weekly for 12 weeks. 25-Hydroxyvitamin D, cholesterol, and lipoprotein subfractions were measured at baseline and after 12 weeks. There was a significant (P < .03) positive association between 25(OH)D and apolipoprotein A-I (Apo A-I) and lipoprotein A-I (Lp A-I). The ratio of low-density lipoprotein to high-density lipoprotein was significantly (P < or = .044) negatively correlated with 25(OH)D levels. The levels of 25(OH)D increased significantly in the treated compared with control group (P < .05). Overall, there were no significant differences between the treated and control groups in any lipoproteins or apolipoproteins after administration of UV irradiation. Subgroup analysis for Apo A-II confined to those with 25(OH)D insufficiency (25[OH]D <75 nmol/L [30 ng/mL]) revealed decreases in Apo A-II in the treated group and increases in the control group that were statistically significantly different between the groups (P = .026). We found a significant positive correlation between 25(OH)D and Apo A-I and Lp A-I and a significant negative correlation between 25(OH)D and the ratio of low-density lipoprotein to high-density lipoprotein. In those with vitamin D insufficiency, we found small decreases in Apo A-II in the treated relative to the control group. Overall, though, twice weekly exposure to UV radiation resulting in an increase in serum 25(OH)D had no significant impact on lipoprotein composition.

Vitamin D deficiency: a worldwide problem with health consequences

Vitamin D deficiency is now recognized as a pandemic. The major cause of vitamin D deficiency is the lack of appreciation that sun exposure in moderation is the major source of vitamin D for most humans. Very few foods naturally contain vitamin D, and foods that are fortified with vitamin D are often inadequate to satisfy either a child's or an adult's vitamin D requirement. Vitamin D deficiency causes rickets in children and will precipitate and exacerbate osteopenia, osteoporosis, and fractures in adults. Vitamin D deficiency has been associated with increased risk of common cancers, autoimmune diseases, hypertension, and infectious diseases. A circulating level of 25-hydroxyvitamin D of >75 nmol/L, or 30 ng/mL, is required to maximize vitamin D's beneficial effects for health. In the absence of adequate sun exposure, at least 800-1000 IU vitamin D3/d may be needed to achieve this in children and adults. Vitamin D2 may be equally effective for maintaining circulating concentrations of 25-hydroxyvitamin D when given in physiologic concentrations.

Sickle cell bone disease: response to vitamin D and calcium

Bone disease with osteoporosis and osteomalacia are common in sickle cell disease (SCD). Some patients have vitamin D deficiency and low bone mineral density (BMD). The role of vitamin D and calcium supplementation to restore bone health in SCD has not been well studied. In 14 adults with SCD, we measured 25(OH)D (25-hydroxyvitamin D) and BMD at the femoral neck, lumbar spine, and distal third of the ulna plus radius, along with markers of bone resorption (CTx; C-terminal component of pro-collagen type I) and bone formation (osteocalcin) before and after 12 months of vitamin D(2) and calcium carbonate treatment. Pretreatment, all patients were vitamin D deficient with a mean 25(OH)D level of 11.6 [corrected] +/- 4 [corrected] ng/ml, had low BMD at the lumbar spine (L-spine), 0.87 +/- 0.11 g/cm(2) (mean Z-score of -2.6 3 +/- 0.71 SD and T score of -2.31 +/- 0.75 SD), femoral neck, 0.8 +/- 0.18 g/cm(2) (mean Z-score -1.36 +/- 0.84, T-score -1.14 +/- 0.75), and the distal radius and ulna, 0.6 +/- 0.17 g/cm(2) (mean Z-score -1.18 +/- 0.79, T-score -1.01 +/- 0.74) and had elevated CTx (0.87 +/- 0.5 ng/ml) and osteocalcin levels (12.3 +/- 3.7 ng/mul). After treatment, all patients corrected their 25(OH)D level (34.6 [corrected] +/- 11 [corrected] ng/ml) (P < 0.001) with a 3.6% +/- 3.9% increase in BMD at the L-spine (P = 0.009), 4.6% +/- 8.5% increase at the femoral neck (P = 0.05) and 6.5% +/- 12.6% increase at the distal radius plus ulna (P = 0.09). CTx, osteocalcin, and PTH(i) levels were unchanged. Treatment of adult SCD with vitamin D and calcium can restore 25(OH)D levels to normal and improve BMD, but, markers of bone resorption remained unchanged. Screening for vitamin D deficiency and BMD in SCD patients seems warranted.

Microsurgical Reconstruction of the Amputated Hand

Fourteen successful results in 16 cases of microsurgical reconstruction of uni- and bilateral hand amputations are reported. Metacarpal reconstruction included the use of titanium alloy for artificial metacarpi, autogenous metatarsals, and autogenous iliac bone grafts. Uni- and bilateral single and multiple donor toes were used in various combinations. Basic hand function and functional sensibility were restored in 14 of 16 cases. There was minimal donor site functional impairment.

Vitamin D2 is as effective as vitamin D3 in maintaining circulating concentrations of 25-hydroxyvitamin D

CONTEXT

Two reports suggested that vitamin D2 is less effective than vitamin D3 in maintaining vitamin D status.

OBJECTIVE

Our objective was to determine whether vitamin D2 was less effective than vitamin D3 in maintaining serum 25-hydroxyvitamin D levels or increased the catabolism of 25-hydroxyvitamin D3.

SUBJECTS AND DESIGN

This was a randomized, placebo-controlled, double-blinded study of healthy adults ages 18-84 yr who received placebo, 1000 IU vitamin D3, 1000 IU vitamin D2, or 500 IU vitamin D2 plus 500 IU vitamin D3 daily for 11 wk at the end of the winter.

RESULTS

Sixty percent of the healthy adults were vitamin D deficient at the start of the study. The circulating levels of 25-hydroxyvitamin D (mean+/-sd) increased to the same extent in the groups that received 1000 IU daily as vitamin D2 (baseline 16.9+/-10.5 ng/ml; 11 wk 26.8+/-9.6 ng/ml), vitamin D3 (baseline 19.6+/-11.1 ng/ml; 11 wk 28.9+/-11.0 ng/ml), or a combination of 500 IU vitamin D2 and 500 IU vitamin D3 (baseline 20.2+/-10.4 ng/ml; 11 wk 28.4+/-7.7 ng/ml). The 25-hydroxyvitamin D3 levels did not change in the group that received 1000 IU vitamin D2 daily. The 1000 IU dose of vitamin D2 or vitamin D3 did not raise 25-hydroxyvitamin D levels in vitamin D-deficient subjects above 30 ng/ml.

CONCLUSION

A 1000 IU dose of vitamin D2 daily was as effective as 1000 IU vitamin D3 in maintaining serum 25-hydroxyvitamin D levels and did not negatively influence serum 25-hydroxyvitamin D3 levels. Therefore, vitamin D2 is equally as effective as vitamin D3 in maintaining 25-hydroxyvitamin D status.

Serum 25-hydroxyvitamin D and bone mineral density in a racially and ethnically diverse group of men

CONTEXT

Although racial and ethnic differences in vitamin D status and bone mineral density (BMD) are recognized, less is known about how differences in vitamin D status impact BMD, especially among men.

OBJECTIVE

Our objective was to examine the relation between serum 25-hydroxyvitamin D [25(OH)D] and BMD by race and ethnic group.

DESIGN

We conducted a population-based, observational survey.

PARTICIPANTS

PARTICIPANTS included 1114 Black, Hispanic, and White men, 30-79 yr of age.

OUTCOMES

We assessed 25(OH)D by a competitive protein binding assay and BMD by dual-energy x-ray absorptiometry.

RESULTS

Mean age +/- SD of the 331 Black, 362 Hispanic, and 421 White men was 48 +/- 12.8 yr. Mean 25(OH)D was lower among Black (25.0 +/- 14.7 ng/ml) and Hispanic (32.9 +/- 13.9 ng/ml) men compared with White men (37.4 +/- 14.0 ng/ml, P < 0.01). A higher percentage of both Black (44%) and Hispanic (23%) men had levels of 25(OH)D in the lowest quartile, compared with 11% of White men (P < 0.001). After adjusting for age, height, and weight, only White men showed significant positive correlation between 25(OH)D and BMD (range of correlations, 0.00-0.14). Serum 25(OH)D was not associated with BMD in Black or Hispanic men at any bone site. Results were similar when adjusted for age only.

CONCLUSIONS

Our findings confirm substantial racial and ethnic group differences in BMD and serum 25(OH)D in men. Serum 25(OH)D and BMD are significantly related to one another in White men only. This may have implications for evaluation of bone health and supplementation in men with low levels of 25(OH)D. Further understanding of the biological mechanisms for these differences between race and ethnic groups is needed.