RESUMO
Rab GTPases are critical regulators of protein trafficking in the cell. To ensure proper cellular localization and function, Rab proteins must undergo a posttranslational modification, termed geranylgeranylation. In the isoprenoid biosynthesis pathway, the enzyme geranylgeranyl diphosphate synthase (GGDPS) generates the 20-carbon isoprenoid donor (geranylgeranyl pyrophosphate [GGPP]), which is utilized in the prenylation of Rab proteins. We have pursued the development of GGDPS inhibitors (GGSI) as a novel means to target Rab activity in cancer cells. Osteosarcoma (OS) and Ewing sarcoma (ES) are aggressive childhood bone cancers with stagnant survival statistics and limited treatment options. Here we show that GGSI treatment induces markers of the unfolded protein response (UPR) and triggers apoptotic cell death in a variety of OS and ES cell lines. Confirmation that these effects were secondary to cellular depletion of GGPP and disruption of Rab geranylgeranylation was confirmed via experiments using exogenous GGPP or specific geranylgeranyl transferase inhibitors. Furthermore, GGSI treatment disrupts cellular migration and invasion in vitro. Metabolomic profiles of OS and ES cell lines identify distinct changes in purine metabolism in GGSI-treated cells. Lastly, we demonstrate that GGSI treatment slows tumor growth in a mouse model of ES. Collectively, these studies support further development of GGSIs as a novel treatment for OS and ES.
Assuntos
Neoplasias Ósseas , Osteossarcoma , Sarcoma de Ewing , Animais , Camundongos , Neoplasias Ósseas/tratamento farmacológico , Farnesiltranstransferase/metabolismo , Osteossarcoma/tratamento farmacológico , Sarcoma de Ewing/tratamento farmacológico , TerpenosRESUMO
CONTEXT AND PURPOSE: There is an urgent need to develop vitamin D dietary recommendations for dark-skinned populations resident at high latitude. Using data from randomised controlled trials (RCTs) with vitamin D3-supplements/fortified foods, we undertook an individual participant data-level meta-regression (IPD) analysis of the response of wintertime serum 25-hydroxyvitamin (25(OH)D) to total vitamin D intake among dark-skinned children and adults residing at ≥ 40° N and derived dietary requirement values for vitamin D. METHODS: IPD analysis using data from 677 dark-skinned participants (of Black or South Asian descent; ages 5-86 years) in 10 RCTs with vitamin D supplements/fortified foods identified via a systematic review and predefined eligibility criteria. Outcome measures were vitamin D intake estimates across a range of 25(OH)D thresholds. RESULTS: To maintain serum 25(OH)D concentrations ≥ 25 and 30 nmol/L in 97.5% of individuals, 23.9 and 27.3 µg/day of vitamin D, respectively, were required among South Asian and 24.1 and 33.2 µg/day, respectively, among Black participants. Overall, our age-stratified intake estimates did not exceed age-specific Tolerable Upper Intake Levels for vitamin D. The vitamin D intake required by dark-skinned individuals to maintain 97.5% of winter 25(OH)D concentrations ≥ 50 nmol/L was 66.8 µg/day. This intake predicted that the upper 2.5% of individuals could potentially achieve serum 25(OH)D concentrations ≥ 158 nmol/L, which has been linked to potential adverse effects in older adults in supplementation studies. CONCLUSIONS: Our IPD-derived vitamin D intakes required to maintain 97.5% of winter 25(OH)D concentrations ≥ 25, 30 and 50 nmol/L are substantially higher than the equivalent estimates for White individuals. These requirement estimates are also higher than those currently recommended internationally by several agencies, which are based predominantly on data from Whites and derived from standard meta-regression based on aggregate data. Much more work is needed in dark-skinned populations both in the dose-response relationship and risk characterisation for health outcomes. TRAIL REGISTRATION: PROSPERO International Prospective Register of Systematic Reviews (Registration Number: CRD42018097260).
Assuntos
Deficiência de Vitamina D , Vitamina D , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Criança , Pré-Escolar , Suplementos Nutricionais , Humanos , Pessoa de Meia-Idade , Necessidades Nutricionais , Estações do Ano , Deficiência de Vitamina D/epidemiologia , Deficiência de Vitamina D/prevenção & controle , Vitaminas , Adulto JovemRESUMO
Geranylgeranyl diphosphate synthase (GGDPS), an enzyme in the isoprenoid biosynthetic pathway (IBP), produces the isoprenoid (geranylgeranyl pyrophosphate, GGPP) used in protein geranylgeranylation reactions. Our prior studies utilizing triazole bisphosphonate-based GGDPS inhibitors (GGSIs) have revealed that these agents represent a novel strategy by which to induce cancer cell death, including multiple myeloma and pancreatic cancer. Statins inhibit the rate-limiting enzyme in the IBP and potentiate the effects of GGSIs in vitro. The in vivo effects of combination therapy with statins and GGSIs have not been determined. Here we evaluated the effects of combining VSW1198, a novel GGSI, with a statin (lovastatin or pravastatin) in CD-1 mice. Twice-weekly dosing with VSW1198 at the previously established maximally tolerated dose in combination with a statin led to hepatotoxicity, while once-weekly VSW1198-based combinations were feasible. No abnormalities in kidney, spleen, brain or skeletal muscle were observed with combination therapy. Combination therapy disrupted protein geranylgeranylation in vivo. Evaluation of hepatic isoprenoid levels revealed decreased GGPP levels in the single drug groups and undetectable GGPP levels in the combination groups. Additional studies with combinations using 50% dose-reductions of either VSW1198 or lovastatin revealed minimal hepatotoxicity with expected on-target effects of diminished GGPP levels and disruption of protein geranylgeranylation. Combination statin/GGSI therapy significantly slowed tumor growth in a myeloma xenograft model. Collectively, these studies are the first to demonstrate that combination IBP inhibitor therapy alters isoprenoid levels and disrupts protein geranylgeranylation in vivo as well as slows tumor growth in a myeloma xenograft model, thus providing the framework for future clinical exploration.
Assuntos
Vias Biossintéticas/efeitos dos fármacos , Diterpenos/administração & dosagem , Sistemas de Liberação de Medicamentos/métodos , Inibidores de Hidroximetilglutaril-CoA Redutases/administração & dosagem , Prenilação de Proteína/efeitos dos fármacos , Terpenos/metabolismo , Triazóis/administração & dosagem , Animais , Vias Biossintéticas/fisiologia , Linhagem Celular Tumoral , Doença Hepática Induzida por Substâncias e Drogas/metabolismo , Doença Hepática Induzida por Substâncias e Drogas/patologia , Diterpenos/toxicidade , Avaliação Pré-Clínica de Medicamentos/métodos , Quimioterapia Combinada , Inibidores Enzimáticos/administração & dosagem , Inibidores Enzimáticos/toxicidade , Farnesiltranstransferase/antagonistas & inibidores , Farnesiltranstransferase/metabolismo , Feminino , Inibidores de Hidroximetilglutaril-CoA Redutases/toxicidade , Lovastatina/administração & dosagem , Lovastatina/toxicidade , Camundongos , Camundongos Endogâmicos NOD , Camundongos SCID , Pravastatina/administração & dosagem , Pravastatina/toxicidade , Prenilação de Proteína/fisiologia , Terpenos/antagonistas & inibidores , Triazóis/toxicidade , Ensaios Antitumorais Modelo de Xenoenxerto/métodosRESUMO
Although there are many recognized health benefits for the consumption of omega-3 (n-3) long-chain polyunsaturated fatty acids (LCPUFA), intake in the United States remains below recommended amounts. This analysis was designed to provide an updated assessment of fish and n-3 LCPUFA intake (eicosapentaenoic (EPA), docosahexaenoic acid (DHA), and EPA+DHA) in the United States adult population, based on education, income, and race/ethnicity, using data from the 2003-2014 National Health and Nutrition Examination Survey (NHANES) (n = 44,585). Over this survey period, participants with less education and lower income had significantly lower n-3 LCPUFA intakes and fish intakes (p < 0.001 for all between group comparisons). N-3 LCPUFA intake differed significantly according to ethnicity (p < 0.001), with the highest intake of n-3 LCPUFA and fish in individuals in the "Other" category (including Asian Americans). Supplement use increased EPA + DHA intake, but only 7.4% of individuals consistently took supplements. Overall, n-3 LCPUFA intake in this study population was low, but our findings indicate that individuals with lower educational attainment and income are at even higher risk of lower n-3 LCPUFA and fish intake.
Assuntos
Escolaridade , Etnicidade , Ácidos Graxos Ômega-3/administração & dosagem , Renda , Adulto , Animais , Dieta , Ácidos Docosa-Hexaenoicos/administração & dosagem , Ácido Eicosapentaenoico/administração & dosagem , Feminino , Peixes , Humanos , Masculino , Inquéritos Nutricionais , Alimentos Marinhos , Estados UnidosRESUMO
The enzyme geranylgeranyl diphosphate synthase (GGDPS) synthesizes the 20-carbon isoprenoid geranylgeranyl pyrophosphate, which is used in geranylgeranylation reactions. We have demonstrated that GGDPS inhibitors in multiple myeloma (MM) cells disrupt Rab geranylgeranylation, leading to inhibition of monoclonal protein trafficking, induction of the unfolded protein response pathway (UPR), and apoptosis. We have previously reported preclinical studies with the GGDPS inhibitor VSW1198, which is a mixture of homogeranyl/homoneryl triazole bisphosphonates. Additional structure-function efforts have led to development of the α-methylated derivatives RAM2093 (homogeranyl) and RAM2061 (homoneryl). As little is known regarding the impact of olefin stereochemistry on drug properties in vivo, we pursued additional preclinical evaluation of RAM2093 and RAM2061. In MM cell lines, both isomers induce activation of UPR/apoptotic markers in a concentration-dependent manner and with similar potency. Single-dose testing in CD-1 mice identified a maximum tolerated i.v. dose of 0.5 mg/kg for RAM2061 and 0.3 mg/kg for RAM2093. Liver toxicity was the primary barrier to dose escalation for both compounds. Disruption of geranylgeranylation in vivo was confirmed after multidose administration of either compound. Pharmacokinetic studies revealed plasma terminal half-lives of 29.2 ± 6 (RAM2061) and 22.1 ± 4 hours (RAM2093). Relative to RAM2061, RAM2093 levels were significantly higher in liver tissue but not in other tissues. Using MM.1S flank xenografts, we observed a significant reduction in tumor growth in mice treated with RAM2061 relative to controls. Collectively, these studies reveal olefin stereochemistry-dependent effects on GGDPS inhibitor biodistribution and confirm the in vivo efficacy of this novel therapeutic approach. SIGNIFICANCE STATEMENT: These studies reveal olefin stereochemistry-dependent effects on the in vivo properties of two novel triazole bisphosphonate inhibitors of geranylgeranyl diphosphate synthase and demonstrate the therapeutic potential of this class of inhibitors for the treatment of multiple myeloma.
Assuntos
Alcenos/farmacologia , Difosfonatos/farmacologia , Farnesiltranstransferase/antagonistas & inibidores , Terpenos/farmacologia , Distribuição Tecidual/efeitos dos fármacos , Triazóis/farmacologia , Alcenos/química , Alcenos/metabolismo , Animais , Difosfonatos/química , Difosfonatos/metabolismo , Relação Dose-Resposta a Droga , Avaliação Pré-Clínica de Medicamentos/métodos , Farnesiltranstransferase/metabolismo , Feminino , Humanos , Camundongos , Camundongos Endogâmicos NOD , Camundongos SCID , Microssomos Hepáticos/efeitos dos fármacos , Microssomos Hepáticos/metabolismo , Estereoisomerismo , Terpenos/química , Terpenos/metabolismo , Distribuição Tecidual/fisiologia , Triazóis/química , Triazóis/metabolismo , Ensaios Antitumorais Modelo de Xenoenxerto/métodosRESUMO
Despite the importance of n-3 fatty acids for health, intakes remain below recommended levels. The objective of this study was to provide an updated assessment of fish and n-3 fatty acid intake (i.e., eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and EPA+DHA) in the United States using the 2003â»2014 National Health and Nutrition Examination Survey (NHANES) data (n = 45,347)). Over this survey period, toddlers, children, and adolescents (aged 1â»19) had significantly lower n-3 fatty acid intake (p < 0.001) compared to adults and seniors, which remained significant after adjusting for caloric intake. Females demonstrated lower n-3 fatty acid intake than males (p < 0.001), with adult and senior women having significantly lower intakes compared to men in the same age categories (p < 0.001) after adjustment for energy intake. Women also consumed less fish than men (5.8 versus 6.1 servings/month, p < 0.001). The estimated intakes of n-3 fatty acids in pregnant women did not differ from non-pregnant women (p = 0.6 for EPA+DHA), although pregnant women reported consuming less high n-3 fatty acid-containing fish than non-pregnant women (1.8 versus 2.6 servings/month, p < 0.001). Our findings indicate that subgroups of the population may be at higher risk of n-3 fatty acid intakes below recommended levels.
Assuntos
Dieta , Ácidos Docosa-Hexaenoicos/administração & dosagem , Ácido Eicosapentaenoico/análogos & derivados , Avaliação Nutricional , Gravidez , Adolescente , Adulto , Idoso , Criança , Pré-Escolar , Ácido Eicosapentaenoico/administração & dosagem , Feminino , Humanos , Lactente , Masculino , Pessoa de Meia-Idade , Inquéritos Nutricionais , Necessidades Nutricionais , Alimentos Marinhos , Estados Unidos , Adulto JovemRESUMO
Vitamin D insufficiency and deficiency can be diagnosed with measurements of serum 25-hydroxyvitamin D (25OHD). Most vitamin D is derived from sunlight (80%), so serum 25OHD levels are lowest in late winter and early spring. Dietary vitamin D in North America is small, about 100 to 200 IU daily. A recent review of the literature shows many association studies relating vitamin D deficiency and insufficiency to several diseases. Large randomized trials of vitamin D are underway and soon there may be answers as to whether vitamin D is clinically effective and what level of serum 25OHD is necessary.
Assuntos
Cálcio da Dieta , Suplementos Nutricionais , Recomendações Nutricionais , Deficiência de Vitamina D/tratamento farmacológico , Vitamina D/análogos & derivados , Idoso , Humanos , Luz Solar , Vitamina D/sangue , Deficiência de Vitamina D/sangueRESUMO
Falls are a serious health problem in the aging population. Because low levels of vitamin D have been associated with increased fall rates, many trials have been performed with vitamin D; two meta-analyses showed either a small effect or no effect of vitamin D on falls. We conducted a study of the effect of vitamin D on serum 25 hydroxyvitamin D (25OHD) and data on falls was collected as a secondary outcome. In a 12-month double blind randomized placebo trial, elderly women, mean age 66 years, were randomized to one of seven daily oral doses of vitamin D or placebo. The main inclusion criterion for study was a baseline serum 25OHD<20ng/ml (50nmol/L). A history of falls was collected at baseline and fall events were collected every 3 months. Results showed that the effect of vitamin D on falls followed a U-shaped curve whether analyzed by dose or serum 25OHD levels. There was no decrease in falls on low vitamin D doses 400, 800 IU, a significant decrease on medium doses 1600, 2400,3200 IU (p=0.020) and no decrease on high doses 4000, 4800 IU compared to placebo (p=0.55). When compared to 12-month serum 25OHD quintiles, the faller rate was 60% in the lowest quintile <25ng/ml (<50nmol/L), 21% in the low middle quintile 32-38ng/ml (80-95nmo/L), 72% in the high middle quintile 38-46ng/ml (95-115nmo/L) and 45% in the highest quintile 46-66ng/ml (115-165nmol/L). In the subgroup with a fall history, fall rates were 68% on low dose, 27% on medium doses and 100% on higher doses. Fall rates on high doses were increased compared to medium doses (Odds Ratio 5.6.95% CI: 2.1-14.8). In summary, the maximum decrease in falls corresponds to a 12- month serum 25OHD of 32-38ng/ml (80-95nmol/L) and faller rates increase as serum 25OHD exceed 40-45ng/ml (100-112.5nmol/L). The Tolerable upper limit (TUL) recently increased in 2010 from 2000 to 4000 IU/day may need to be reduced in elderly women especially in those with a fall history.
Assuntos
Acidentes por Quedas/prevenção & controle , Colecalciferol/administração & dosagem , Vitamina D/administração & dosagem , Vitaminas/administração & dosagem , Idoso , Colecalciferol/sangue , Colecalciferol/uso terapêutico , Suplementos Nutricionais/análise , Método Duplo-Cego , Feminino , Humanos , Pessoa de Meia-Idade , Vitamina D/análogos & derivados , Vitamina D/sangue , Vitamina D/uso terapêutico , Deficiência de Vitamina D/sangue , Deficiência de Vitamina D/tratamento farmacológico , Vitaminas/sangue , Vitaminas/uso terapêuticoRESUMO
OBJECTIVE: This study aims to prospectively assess the incidence of hypercalciuria and hypercalcemia with different doses of vitamin D and with a calcium intake of approximately 1,200 mg/day. METHODS: This was a 1-year randomized placebo-controlled study of vitamin D (400-4,800 IU/d) in 163 white women aged 57 to 90 years. Calcium citrate tablets (200 mg) were added to the diet to achieve a total calcium intake of approximately 1,200 mg/day in all groups. All women had vitamin D insufficiency at baseline, with serum 25-hydroxyvitaminD levels lower than 20 ng/mL (50 nmol/L). Serum and 24-hour urine calcium were collected every 3 months on supplementation, any test result above the upper reference range represented an episode of hypercalcemia or hypercalciuria. Mixed-effects models and multivariate logistic regression were used in the analysis. RESULTS: Hypercalcemia (>10.2 mg/dL [2.55 mmol/L]) occurred in 8.8% of white women. Hypercalciuria (>300 mg/d [7.5 mmol]) occurred in 30.6% of white women. Episodes of hypercalciuria were transient in half of the group and recurrent in the other half. No relationship between hypercalcemia or hypercalciuria and vitamin D dose was found, and hypercalciuria was equally common in the placebo group. CONCLUSIONS: Hypercalciuria and hypercalcemia commonly occur with vitamin D and calcium supplements. Whether hypercalciuria and hypercalcemia are caused by calcium, vitamin D, or both is unclear. These findings may have relevance to the reported increase in kidney stones in the Women's Health Initiative trial. Because calcium 1,200 mg and vitamin D 800 IU/day are widely recommended in postmenopausal women, systematic evaluation of the safety of supplements is warranted in clinical management and in future studies.
Assuntos
Citrato de Cálcio/administração & dosagem , Citrato de Cálcio/efeitos adversos , Hipercalcemia/induzido quimicamente , Hipercalciúria/induzido quimicamente , Vitamina D/administração & dosagem , Vitamina D/efeitos adversos , Idoso , Idoso de 80 Anos ou mais , Cálcio/sangue , Cálcio/urina , Suplementos Nutricionais/efeitos adversos , Relação Dose-Resposta a Droga , Feminino , Humanos , Pessoa de Meia-Idade , Placebos , Pós-Menopausa , Estudos Prospectivos , Curva ROC , Vitamina D/análogos & derivados , Vitamina D/sangue , População Branca , Saúde da MulherRESUMO
There is limited information on the effects of vitamin D on serum 25 hydroxyvitamin D (25OHD) in young people and none on African Americans. The main objective of this trial was to measure the effect of different doses of vitamin D3 on serum 25OHD and serum parathyroid hormone (PTH) in young women with vitamin D insufficiency (serum 25OHD ≤ 20 ng/mL (50 nmol/L). A randomized double-blind placebo-controlled trial of vitamin D3 was conducted in young white and African American women, age 25 to 45 years. A total of 198 healthy white (60%) and African American (40%) women were randomly assigned to placebo, or to 400, 800, 1600, or 2400 IU of vitamin D3 daily. Calcium supplements were added to maintain a total calcium intake of 1000 to 1200 mg daily. The primary outcomes of the study were the final serum 25OHD and PTH levels at 12 months. The absolute increase in serum 25OHD with 400, 800, 1600, and 2400 IU of vitamin D daily was slightly greater in African American women than in white women. On the highest dose of 2400 IU/d, the mixed model predicted that mean 25OHD increased from baseline 12.4 ng/mL (95% confidence interval [CI], 9.2-15.7) to 43.2 ng/mL (95% CI, 38.2-48.1) in African American women and from 15.0 ng/mL (95% CI, 12.3-17.6) to 39.1 ng/mL (95% CI, 36.2-42.0) in white women. There was no significant effect of vitamin D dose on serum PTH in either race but there was a significant inverse relationship between final serum PTH and serum 25OHD. Serum 25OHD exceeded 20 ng/mL in 97.5% of whites on the 400 IU/d dose and between 800 and 1600 IU/d for African Americans. The recommended dietary allowance (RDA) suggested by the Institute of Medicine for young people is 600 IU daily. The increase in serum 25OHD after vitamin D supplementation was similar in young and old, and in white and African American women.
Assuntos
Negro ou Afro-Americano , Colecalciferol/administração & dosagem , Deficiência de Vitamina D/tratamento farmacológico , Vitamina D/análogos & derivados , População Branca , Adulto , Cálcio/uso terapêutico , Método Duplo-Cego , Feminino , Humanos , Pessoa de Meia-Idade , Hormônio Paratireóideo/sangue , Vitamina D/sangue , Deficiência de Vitamina D/sangueRESUMO
It is commonly said that vitamin D should be used to increase calcium absorption. We tested this statement in a dose-response study of vitamin D on calcium absorption. A total of 198 white and African American women, aged 25 to 45 years, with vitamin D insufficiency, serum 25-hydroxyvitamin D (25OHD) <20 ng/mL, were randomized in a double-blind study to vitamin D3 400, 800, 1600, 2400 IU, or placebo. A calcium supplement was given to increase mean calcium intake at baseline from 706 mg/d to 1031 mg/d. Calcium absorption was measured at baseline and after 12 months using a single isotope method with radiocalcium45 and 100 mg of calcium. Mean baseline serum 25OHD was 13.4 ng/mL (33.5 nmol/L) and increased to 40 ng/mL (100 nmol/L) on the highest dose of 2400 IU. Using a multivariate regression analysis with significant predictors, baseline absorption, calcium intake, and weight, there was no increase in 12-month calcium absorption compared with baseline on any dose of vitamin D in either whites or African Americans. There was no significant relationship between 12-month calcium absorption and final serum 25OHD. In an analysis of calcium absorption and serum 25OHD at baseline, serum 25OHD levels were divided into groups: 0 to 5, 6 to 10, 11 to 15, or 16 to 20 ng/mL. There was no evidence of a threshold decrease in calcium absorption or serum 1,25 dihydroxyvitamin D (1,25(OH)2 D) amongst the lowest groups. Vitamin D doses up to 2400 IU daily did not increase calcium absorption. No threshold level of serum 25OHD for calcium absorption was found at baseline or in the longitudinal study, suggesting that active transport of calcium is saturated at very low serum 25OHD levels <5 ng/mL. There is no need to recommend vitamin D for increasing calcium absorption in normal subjects. Very efficient calcium absorption at very low levels of serum 25OHD explains why people do not develop osteomalacia provided that dietary intakes of calcium and phosphorus are adequate.
Assuntos
Cálcio/sangue , Vitamina D/análogos & derivados , Adulto , Negro ou Afro-Americano , Método Duplo-Cego , Feminino , Humanos , Pessoa de Meia-Idade , Vitamina D/administração & dosagem , Vitamina D/farmacocinética , População BrancaRESUMO
CONTEXT: Serum 25-hydroxyvitamin D (25OHD) is lower in women with darker skin color. Is it due to lower skin production, lower absorption, or different metabolism of vitamin D? OBJECTIVES: The objective of the study was to measure the effect of vitamin D3 on serum 25OHD and serum PTH in older African American women with vitamin D insufficiency and the serum 25OHD 20 ng/mL or less (<50 nmol/L). The results can be used to estimate the Recommended Dietary Allowance (RDA). DESIGN AND SETTING: This was a randomized, double-blind placebo trial at Creighton University Medical Center and Indiana University Medical Center. PARTICIPANTS: Participants were 110 healthy older African American women. INTERVENTIONS: The intervention consisted of participants randomly assigned to placebo, vitamin D3 400, 800, 1600, 2400, 3200, 4000, or 4800 IU daily; calcium supplements were given to maintain total calcium intake of 1200-1400 mg/d. MAIN OUTCOME MEASUREMENTS: Change in serum 25OHD and serum PTH levels at 12 months was measured. RESULTS: Mean baseline serum 25OHD was 13 ng/mL (33 nmol/L). On 4800 IU, serum 25OHD averaged 50 ng/mL (125 nmol/L) compared with 47 ng/mL (117 nmol/L) in Caucasian women. Serum PTH at 12 months decreased significantly (P = .008) when related to serum 25OHD but not dose. Hypercalcemia occurred in 7% and hypercalciuria in 15%. Events were unrelated to vitamin D dose. CONCLUSION: Vitamin D3 800 IU increased serum 25OHD greater than 20 ng/mL (>50 nmol/L) in 97.5% of the African American women just as it did in the Caucasian women, and therefore, the RDA is the same for both groups. Because absorption and metabolism of oral vitamin D absorption is similar in both groups, lower levels of serum 25OHD in African Americans must be due to lower production of vitamin D in skin.
Assuntos
Negro ou Afro-Americano , Colecalciferol/administração & dosagem , Deficiência de Vitamina D/sangue , Deficiência de Vitamina D/tratamento farmacológico , Vitaminas/administração & dosagem , Idoso , Idoso de 80 Anos ou mais , Envelhecimento/sangue , Cálcio da Dieta/administração & dosagem , Colecalciferol/efeitos adversos , Relação Dose-Resposta a Droga , Método Duplo-Cego , Feminino , Humanos , Pessoa de Meia-Idade , Hormônio Paratireóideo/sangue , Placebos , Estudos Prospectivos , Vitamina D/análogos & derivados , Vitamina D/sangue , Deficiência de Vitamina D/etnologia , Vitaminas/efeitos adversos , População BrancaRESUMO
Obese people are known to have lower serum 25OHD levels compared to non-obese people. It is not known whether it is due to storage of vitamin D in fat, inadequate input from sunlight, diet or other unknown factors. We examined the relationship at study baseline of serum 25OHD, PTH, 1,25(OH)2D with body composition measurements using dual energy X-ray absorptiometry. The results showed a significant inverse relation between total body fat mass and serum 25OHD (p<0.0001) and serum 1,25(OH2)D (p=034) and an independent positive correlation between serum PTH and total body fat mass (p<0.0001). In a randomized controlled study of seven doses of vitamin D (400-4800IU/d) the increase in serum 25OHD levels was compared in women with a normal body mass index to obese women. The response to the low doses of vitamin D (400-800IU/d) was significantly less than that of the medium (1600-2400IU/d) and high doses groups (3200-4800IU) (p<0.0001) in all BMI categories. The increase in serum 25OHD in the medium and high dose groups was not significantly different with increasing level of obesity. But thinner women with a normal BMI (<25kg/m(2)) showed a much higher response to vitamin D at any dose level compared to other BMI groups. There was no significant change in total body fat mass after treatment with vitamin D or calcitriol in our randomized trials. In summary, the response to vitamin D is dependent on body weight. Women with BMI <25kg/m(2) develop much higher levels of serum 25OHD after vitamin D supplementation compared to those with BMI of >25kg/m(2). The differences in serum 25OHD levels between normal and obese women may be due to differences in volume dilution. After vitamin D supplementation, all obese women reach adequate levels of serum 25OHD but normal women (BMI<25kg/m(2)) reach much higher levels of 25OHD and in this group smaller doses of vitamin D used should be used. This article is part of a Special Issue entitled 'Vitamin D Workshop'.
Assuntos
Obesidade/sangue , Obesidade/dietoterapia , Vitamina D/análogos & derivados , Vitamina D/administração & dosagem , Idoso , Idoso de 80 Anos ou mais , Composição Corporal/efeitos dos fármacos , Composição Corporal/fisiologia , Índice de Massa Corporal , Calcitriol/administração & dosagem , Suplementos Nutricionais , Método Duplo-Cego , Feminino , Humanos , Estudos Longitudinais , Pessoa de Meia-Idade , Obesidade/patologia , Vitamina D/sangueRESUMO
CONTEXT: Vitamin D is often recommended for use with calcium supplements to increase absorption. There are no systematic studies of vitamin D on calcium absorption that indicate what dose should be recommended. OBJECTIVE: Our objective was to study the effect of increasing doses of vitamin D3 on calcium absorption. DESIGN AND SETTING: We conducted a randomized double-blind placebo-controlled trial at Creighton University Medical Center, Omaha, NE. PARTICIPANTS: Participants included 163 postmenopausal Caucasian women with vitamin D insufficiency, defined as a serum 25-hydroxyvitamin D (25OHD) below 20 ng/ml (50 nmol/liter). INTERVENTION: Participants were randomized to receive one of the vitamin D3 doses, 400, 800, 1600, 2400, 3200, 4000, or 4800 IU/d, or placebo for 1 yr. Calcium intake was increased to 1200-1400 mg daily by giving daily calcium citrate. MAIN OUTCOME: We evaluated the change in calcium absorption on vitamin D. RESULTS: Mean serum 25OHD increased from baseline 15.6 ng/ml (39 nmol/liter) to 46.5 ng/ml (112 nmol/liter) in subjects randomized to the highest dose of vitamin D (4800 IU). Calcium absorption was more significantly related to serum 25OHD (R2=0.50; P=0.001) than dose (R2=0.47; P=0.033). Calcium absorption of a 100-mg dose increased from 52-58% (6 mg) over a serum 25OHD range of 20-66 ng/ml (50-165 nmol/liter). CONCLUSIONS: There was no evidence of a threshold for reduced calcium absorption in the serum 25OHD range of 10-66 ng/ml (25-165 nmol/liter). The increase in absorbed calcium of 6% on high doses of vitamin D is so small that the same amount could be obtained from half a glass of milk (100 ml) or 100 mg elemental calcium. The results challenge assumptions about the value of adding vitamin D to increase calcium absorption except when serum 25OHD is very low that is less than 10 ng/ml (25 nmol/liter).
Assuntos
Citrato de Cálcio/farmacocinética , Colecalciferol/administração & dosagem , Absorção Intestinal/efeitos dos fármacos , Deficiência de Vitamina D/tratamento farmacológico , Vitaminas/administração & dosagem , Idoso , Idoso de 80 Anos ou mais , Relação Dose-Resposta a Droga , Método Duplo-Cego , Interações Medicamentosas , Feminino , Seguimentos , Aditivos Alimentares/farmacocinética , Humanos , Pessoa de Meia-Idade , Pós-Menopausa/metabolismo , Resultado do Tratamento , Vitamina D/análogos & derivados , Vitamina D/sangue , Deficiência de Vitamina D/metabolismoRESUMO
Pancreatic cancer is one of the most lethal cancers in the world, as it continues to be resistant to any therapeutic approaches. The high molecular weight glycoprotein mucin 4 (MUC4) is aberrantly expressed in pancreatic cancer and contributes to the regulation of differentiation, proliferation, metastasis, and the chemoresistance of pancreatic cancer cells. The absence of its expression in the normal pancreatic ductal cells makes MUC4 a promising target for novel cancer therapeutics. Natural products have been widely investigated as potential candidates in cancer therapies, and thymoquinone (TQ), extracted from the seeds of Nigella sativa, has shown excellent antineoplastic properties in some systems. In the present study, we evaluated the effect of TQ on pancreatic cancer cells and specifically investigated its effect on MUC4 expression. The MUC4-expressing pancreatic cancer cells FG/COLO357 and CD18/HPAF were incubated with TQ, and in vitro functional assays were done. The results obtained indicate that treatment with TQ downregulated MUC4 expression through the proteasomal pathway and induced apoptosis in pancreatic cancer cells by the activation of c-Jun NH(2)-terminal kinase and p38 mitogen-activated protein kinase pathways. In agreement with previous studies, the decrease in MUC4 expression correlated with an increase in apoptosis, decreased motility, and decreased migration of pancreatic cancer cells. MUC4 transient silencing studies showed that c-Jun NH(2)-terminal kinase and p38 mitogen-activated protein kinase pathways are activated in pancreatic cancer cells, indicating that the activation of these pathways by TQ is directly related to the MUC4 downregulation induced by the drug. Overall, TQ has potential for the development of novel therapies against pancreatic cancer.
Assuntos
Benzoquinonas/farmacologia , Carcinoma Ductal Pancreático/genética , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Mucina-4/genética , Neoplasias Pancreáticas/tratamento farmacológico , Neoplasias Pancreáticas/genética , Antineoplásicos/uso terapêutico , Apoptose/efeitos dos fármacos , Apoptose/genética , Benzoquinonas/uso terapêutico , Carcinoma Ductal Pancreático/tratamento farmacológico , Carcinoma Ductal Pancreático/metabolismo , Carcinoma Ductal Pancreático/patologia , Movimento Celular/efeitos dos fármacos , Movimento Celular/genética , Citoesqueleto/efeitos dos fármacos , Citoesqueleto/metabolismo , Relação Dose-Resposta a Droga , Regulação para Baixo/efeitos dos fármacos , Desenho de Fármacos , Avaliação Pré-Clínica de Medicamentos , Perfilação da Expressão Gênica , Humanos , Mucina-4/metabolismo , Análise de Sequência com Séries de Oligonucleotídeos , Neoplasias Pancreáticas/metabolismo , Neoplasias Pancreáticas/patologia , Células Tumorais CultivadasRESUMO
BACKGROUND: The reduced folate carrier (RFC1) is an integral membrane protein and facilitative anion exchanger that mediates delivery of 5-methyltetrahydrofolate into mammalian cells. Adequate maternal-fetal transport of folate is necessary for normal embryogenesis. Targeted inactivation of the murine RFC1 gene results in post-implantation embryolethality, but daily folic acid supplementation of pregnant dams prolongs survival of homozygous embryos until mid-gestation. At E10.5 RFC1-/- embryos are developmentally delayed relative to wildtype littermates, have multiple malformations, including neural tube defects, and die due to failure of chorioallantoic fusion. The mesoderm is sparse and disorganized, and there is a marked absence of erythrocytes in yolk sac blood islands. The identification of alterations in gene expression and signaling pathways involved in the observed dysmorphology following inactivation of RFC1-mediated folate transport are the focus of this investigation. RESULTS: Affymetrix microarray analysis of the relative gene expression profiles in whole E9.5 RFC1-/- vs. RFC1+/+ embryos identified 200 known genes that were differentially expressed. Major ontology groups included transcription factors (13.04%), and genes involved in transport functions (ion, lipid, carbohydrate) (11.37%). Genes that code for receptors, ligands and interacting proteins in the cubilin-megalin multiligand endocytic receptor complex accounted for 9.36% of the total, followed closely by several genes involved in hematopoiesis (8.03%). The most highly significant gene network identified by Ingenuitytrade mark Pathway analysis included 12 genes in the cubilin-megalin multiligand endocytic receptor complex. Altered expression of these genes was validated by quantitative RT-PCR, and immunohistochemical analysis demonstrated that megalin protein expression disappeared from the visceral yolk sac of RFC1-/- embryos, while cubilin protein was widely misexpressed. CONCLUSION: Inactivation of RFC1 impacts the expression of several ligands and interacting proteins in the cubilin-amnionless-megalin complex that are involved in the maternal-fetal transport of folate and other nutrients, lipids and morphogens such as sonic hedgehog (Shh) and retinoids that play critical roles in normal embryogenesis.
Assuntos
Desenvolvimento Embrionário , Proteína-2 Relacionada a Receptor de Lipoproteína de Baixa Densidade/metabolismo , Troca Materno-Fetal , Receptores de Superfície Celular/metabolismo , Proteína de Replicação C/metabolismo , Fatores de Transcrição/metabolismo , Animais , Embrião de Mamíferos/metabolismo , Endocitose , Feminino , Redes Reguladoras de Genes , Proteína-2 Relacionada a Receptor de Lipoproteína de Baixa Densidade/química , Proteínas de Membrana/química , Proteínas de Membrana/metabolismo , Camundongos , Camundongos Knockout , Modelos Moleculares , Análise de Sequência com Séries de Oligonucleotídeos , Reação em Cadeia da Polimerase , Gravidez , Receptores de Superfície Celular/química , Proteína de Replicação C/genética , Fatores de Transcrição/genéticaRESUMO
During general anesthesia the possibility of subconscious perception of intraoperative events is a controversial subject. Some studies found that positive verbal suggestions, or music improved intraoperative relaxation and postoperative recovery. The aim of the current study was to evaluate the effect of prayer and relaxation technique applied while patients are under general anesthesia for open-heart surgery. A randomized, controlled, double-blind trial study included 78 patients who underwent cardiac surgery. During the surgery the patients used a headphone connected to a CD player. They were randomly divided into three groups. One group listened to prayer during the surgery, the other listened to relaxation technique and one, placebo. There was only one significant finding: the prayer group is less likely to believe that prayer would assist conventional medical treatments. Although not statistically significant, we discussed the length of stay (LOS) after surgery and the incidence of sternal wound infection.