Molybdenum absorption and utilization in humans from soy and kale intrinsically labeled with stable isotopes of molybdenum

Resorbable Patient-Specific Implants of Molybdenum for Pediatric Craniofacial Surgery-Proof of Concept in an In Vivo Pilot Study

Titanium continues to be the gold standard in the field of osteosynthesis materials. This also applies to pediatric craniofacial surgery. Various resorbable materials have already been developed in order to avoid costly and risky second operations to remove metal in children. However, none of these resorbable materials have been able to completely replace the previous gold standard, titanium, in a satisfactory manner. This has led to the need for a new resorbable osteosynthesis material that fulfills the requirements for biocompatibility, stability, and uniform resorption. In our previous in vitro and in vivo work, we were able to show that molybdenum fulfills these requirements. To further confirm these results, we conducted a proof of concept in four domestic pigs, each of which was implanted with a resorbable molybdenum implant. The animals were then examined daily for local inflammatory parameters. After 54 days, the animals were euthanized with subsequent computer tomography imaging. We also removed the implants together with the surrounding tissue and parts of the spleen, liver, and kidney for histopathological evaluation. The molybdenum implants were also analyzed metallographically and using scanning electron microscopy. A blood sample was taken pre- and post-operatively. None of the animals showed clinical signs of inflammation over the entire test period. Histopathologically, good tissue compatibility was found. Early signs of degradation were observed after 54 days, which were not sufficient for major resorption. Resorption is expected with longer in situ residence times based on results of similar earlier investigations.

The mussel Mytilus galloprovincialis (Crimea, Black Sea) as a source of essential trace elements in human nutrition

Micronutrients, or essential trace elements, are important components in various metabolic processes inherent to the normal functioning of organism. To date, a substantial part of the world population suffers from a lack of micronutrients in the diet. Mussels are an important and cheap source of nutrients, which can be utilized to mitigate the micronutrient deficiency in the world. In the present work, using inductively coupled plasma mass spectrometry, the contents of the micronutrients Cr, Fe, Cu, Zn, Se, I, and Mo were studied for the first time in soft tissues, shell liquor, and byssus of females and males of the mussel Mytilus galloprovincialis as the promising sources of essential elements in the human diet. Fe, Zn, and I were the most abundant micronutrients in the three body parts. Significant sex-related differences in the body parts were detected only for Fe, which was more abundant in byssus of males, and Zn, which exhibited higher levels in shell liquor of females. Significant tissue-related differences were registered in the contents of all the elements under study. M. galloprovincialis meat was characterized as the optimal source of I and Se for covering the daily human needs. Regardless of sex, byssus turned out to be richer in Fe, I, Cu, Cr, and Mo in comparison with soft tissues, which fact allows recommending this body part for the preparation of dietary supplements to compensate for the deficiency of these micronutrients in the human body.

OECD 414 supplementary prenatal developmental toxicity study of sodium molybdate dihydrate in the rat and benchmark dose evaluation

In a continuing investigation of the potential for reproductive and developmental toxicity of molybdenum (Mo), consequent to the previous published OECD studies [1,2] and as directed by the European Chemicals Agency [3], a supplemental rat GLP-compliant Prenatal Developmental Toxicity (PNDT) study was conducted to investigate higher dose levels of sodium molybdate dihydrate (SMD) in an identical study design (OECD 414)[4] to Murray et al. 2014a [1], at dietary concentrations calculated to provide target Mo levels of 80 and 120 mg/kg bw/day (the maximum-tolerated dose). There was no effect on post-implantation loss, litter size, sex ratio or the incidence of external, visceral or skeletal fetal malformations or variations. Fetal weight was reduced proportionate to maternal dose. Minimal differences observed in the ossification status of some extremities of fetuses from females receiving 120 mg Mo/kg bw/day were confirmed as transient by skeletal examination of PND 21 pups from a further group of females receiving the same dose regime. There was no evidence of copper depletion in serum, placenta or liver. A benchmark dose evaluation using continuous and dichotomous approaches by combining the fetal body weight data from this study and the previous study determined that the BMD05 ranged from 47 to 57 mg Mo/kg bw/day, depending on the modelling approach and the BMDL05 estimates ranged from 37 to 47 mg Mo/kg bw/day. These levels are considered a more statistically robust point of departure for risk assessment for reproductive effects than the established NOAEL of 40 mg Mo/kg bw/day.

Does the Micronutrient Molybdenum Have a Role in Gestational Complications and Placental Health?

Molybdenum is an essential trace element for human health and survival, with molybdenum-containing enzymes catalysing multiple reactions in the metabolism of purines, aldehydes, and sulfur-containing amino acids. Recommended daily intakes vary globally, with molybdenum primarily sourced through the diet, and supplementation is not common. Although the benefits of molybdenum as an anti-diabetic and antioxidant inducer have been reported in the literature, there are conflicting data on the benefits of molybdenum for chronic diseases. Overexposure and deficiency can result in adverse health outcomes and mortality, although physiological doses remain largely unexplored in relation to human health. The lack of knowledge surrounding molybdenum intake and the role it plays in physiology is compounded during pregnancy. As pregnancy progresses, micronutrient demand increases, and diet is an established factor in programming gestational outcomes and maternal health. This review summarises the current literature concerning varied recommendations on molybdenum intake, the role of molybdenum and molybdoenzymes in physiology, and the contribution these play in gestational outcomes.

Molybdenum as a Potential Biocompatible and Resorbable Material for Osteosynthesis in Craniomaxillofacial Surgery-An In Vitro Study

Titanium and stainless steel are commonly known as osteosynthesis materials with high strength and good biocompatibility. However, they have the big disadvantage that a second operation for hardware removal is necessary. Although resorbable systems made of polymers or magnesium are increasingly used, they show some severe adverse foreign body reactions or unsatisfying degradation behavior. Therefore, we started to investigate molybdenum as a potential new biodegradable material for osteosynthesis in craniomaxillofacial surgery. To characterize molybdenum as a biocompatible material, we performed in vitro assays in accordance with ISO Norm 10993-5. In four different experimental setups, we showed that pure molybdenum and molybdenum rhenium alloys do not lead to cytotoxicity in human and mouse fibroblasts. We also examined the degradation behavior of molybdenum by carrying out long-term immersion tests (up to 6 months) with molybdenum sheet metal. We showed that molybdenum has sufficient mechanical stability over at least 6 months for implants on the one hand and is subject to very uniform degradation on the other. The results of our experiments are very promising for the development of new resorbable osteosynthesis materials for craniomaxillofacial surgery based on molybdenum.

Molybdenum - A biodegradable implant material for structural applications?

Molybdenum as a potentially new biodegradable material was investigated. Degradation behavior of commercially high purity molybdenum was observed in simulated physiological salt solutions (Kokubo's SBF with/without TRIS-HCl, Cu²⁺ addition and 0.9% NaCl solution). Potentiodynamic polarization, immersion mass loss and ion concentration measurements paired with REM/EDX analysis reveal gradual dissolution of molybdenum in the proper order of magnitude for stent application, associated with formation of thin, non-passivating corrosion products. The underlying corrosion mechanism is discussed as well as a comparison to literature data. However, formation of calcium phosphates (CaP) in SBF significantly decreases corrosion rates. In-situ polarization was found to be a potential way for overcoming this problem and simultaneously enhancing corrosion above the benchmark for a degradable stent material. STATEMENT OF SIGNIFICANCE: Biodegradable metals have the potential to overcome severe complications common to orthopedic and cardio-vascular implants. However, the need for a material with moderate and predictable degradation, high strength and toughness as well as MRI suitability must be satisfied. Molybdenum as potential new biodegradable material may just fulfill these requirements. An overall positive picture of molybdenum as an interesting alternative to recently discussed metallic biodegradable materials can be concluded from the herein presented results and from literature data, showing directions for future research on the topic.

Stable Isotopes of Minerals as Metabolic Tracers in Human Nutrition Research

Enriched stable isotopes used as tracers have proven to be valuable in studies of the absorption and metabolism of minerals. Unlike radioisotopes, they can be used in high-risk population groups such as infants, children, and pregnant or lactating women. Estimates of mineral absorption can be made from the oral administration of a single tracer or from two tracers, one given orally and the other intravenously (IV). It is possible to determine the metabolism of the mineral with modeling based on the amount of the tracer or tracers in different biological samples. One of the key decisions in studies of this type is determining which enriched isotope and what amount to use. An example is given of calculations to estimate and compare the amounts of tracers needed for an absorption study. Methods for calculating the amounts of tracer in oral and IV doses are presented, and limits of detection and quantitation are discussed in terms of percent of enrichment and related to isotope ratio measurement precision. A general review of the use of mass spectrometric instruments for quantifying various stable isotopes is given.

Molybdenum and copper in four varieties of common bean (Phaseolus vulgaris): new data of potential utility in designing healthy diet for diabetic patients

Experimental evidence indicates that diabetic patients and individuals with impaired copper homeostasis could be at risk of molybdenum toxicity. A self-administered food frequency questionnaire revealed that in central Mexico, diabetic patients with severe complications tend to consume beans more often than individuals with less advanced disease. Four varieties of Phaseolus vulgaris were comparatively evaluated as the dietary sources of two elements; the results showed molybdenum concentration decreasing in the order peruvian > pinto > mayflower > black, whereas for copper, the order was peruvian > pinto ∼ black > mayflower. The two elements were determined in pre-soaking water, cooked legumes, and broth obtained in cooking procedure; an in vitro gut model was also applied to assess potentially bioavailable fraction of both elements in cooked beans. The results indicated that the black variety would be the healthiest bean choice for diabetic patients and individuals susceptible to Mo toxicity. Relatively low total molybdenum was found in this variety (2.9 ± 1.4 versus 4.3-10.9 μg g(-1) in other types), element availability was also low (15 % in supernatant from enzymolysis, 24.9 % in combined broth + supernatant fractions), and the molar ratio of Cu/Mo was the highest among four types (41, versus Cu/Mo <10 in peruvian, pinto, or mayflower). Considering peruvian and pinto beans, broth elimination would help to lower molybdenum intake with marginal effect on Cu/Mo molar ratio. This recommendation would be especially important for peruvian variety, which provided 1090, 803, and 197 μg day(-1) of molybdenum in raw grains, broth + supernatant, and supernatant, respectively (based on 100-g portion), exceeding the recommended daily allowance of 45 μg day(-1).

Reactive-oxygen-species-mediated Cdc25C degradation results in differential antiproliferative activities of vanadate, tungstate, and molybdate in the PC-3 human prostate cancer cell line

The differential antiproliferative effects of vanadate, tungstate, and molybdate on human prostate cancer cell line PC-3 were compared and the underlying mechanisms were investigated. The results demonstrate that all of the three oxoanions can cause G(2)/M cell cycle arrest, which is evidenced by the increase in the level of phosphorylated Cdc2 at its inactive Tyr-15 site. Moreover, even if the difference in cellular uptake among the three oxoanions is excluded from the possible factors affecting their antiproliferative activity, vanadate exerted a much more potent effect in PC-3 cells than the other two oxoanions. Our results also reveal that reactive oxygen species (ROS)-mediated degradation of Cdc25C rather than Cdc25A or Cdc25B is responsible for vanadate-induced G(2)/M cell cycle arrest. We propose a possible mechanism to clarify the differential effect of the three oxoanions in biological systems beyond just considering that they are structural analogs of phosphate. We suggest that ROS formation is unlikely to be involved in the biological function of tungstate and molybdate, whereas the redox properties of vanadium may be important factors for it to exert pharmacological effects. Further, given the evidence from epidemiology studies of the association between diabetes and prostate cancer, the possibility of vanadate as a good candidate as both an antidiabetic and an anticancer agent or a chemopreventive agent is indicated.

Molybdenum Nutriture in Humans

Molybdenum is a trace element that functions as a cofactor for at least 4 enzymes: sulfite oxidase, xanthine oxidase, aldehyde oxidase, and mitochondrial amidoxime reducing component. In each case, molybdenum is bound to a complex, multiring organic component called molybdopterin, forming the entity molybdenum cofactor. The best sources of dietary molybdenum are legumes, grains, and nuts. Bioavailability of molybdenum is fairly high but depends on form, with molybdenum preparations having greater bioavailability than food-bound molybdenum. Molybdenum deficiency and toxicity are rare, possibly because of the body’s ability to adapt to a wide range of molybdenum intake levels. At low intakes of molybdenum, the fractional transfer of molybdenum from plasma to urine is lower and a greater fraction is deposited into tissues, and at high intakes of molybdenum, the opposite occurs. Molybdenum has proven to be an interesting trace mineral that is essential for life.

A recycling systemic model for the biokinetics of molybdenum radionuclides

An overview of the available data on molybdenum biokinetics and metabolism in humans is presented, with special emphasis on the results of stable tracer studies conducted in recent years, after the publication of the systemic model for incorporated radionuclides of molybdenum recommended by the International Commission on Radiological Protection (ICRP). On the basis of the presented information, a new structure for a compartmental model of molybdenum biokinetics, including the return of material from the organs back to the systemic circulation, was developed. The structure chosen is a compromise between the attempt to provide a realistic description of the biokinetics and the need to have a simple tool for dose estimation. The model consists of two compartments associated to the extracellulare fluids (blood plasma and interstitial fluids), liver, kidneys, and one generic compartment to represent all other tissues. The possibility of a direct excretion pathway into the urine was introduced, in order to correctly describe the rapid excretion as observed in the human studies. Reference values of the model parameters have been estimated taking into consideration that the amounts of radioactive molybdenum accidentally incorporated are negligible in comparison to the daily dietary intake of stable molybdenum.

Molybdenum intake influences molybdenum kinetics in men

The objectives of this study were to determine physiologic adaptations that occur when humans are exposed to a wide range of molybdenum intake levels and to identify the pathways that are influenced by dietary intake. Four males consumed each of 5 daily molybdenum intakes of 22, 72, 121, 467, and 1490 microg/d (0.23, 0.75, 1.3, 4.9, and 15.5 micromol/d) for 24 d each. During each treatment period, oral and intravenous doses of (100)Mo and (97)Mo were administered. Serial plasma, urine, and fecal samples were analyzed for labeled and unlabeled molybdenum. Compartmental modeling was used to determine rates of distribution and elimination at each dietary intake level. Three pathways were sensitive to daily molybdenum intake. With increasing intake, absorption and urinary molybdenum excretion increased, whereas the fraction deposited in tissues decreased. Kinetic analysis suggested a daily intake of 115-120 microg/d (1.20-1.25 micromol/d) would maintain initial plasma molybdenum levels at their prestudy values and that their prestudy dietary intake was well above the Recommended Dietary Allowance of 45 microg/d. The physiological adaptations to changing intake that the model demonstrated may help prevent molybdenum deficiency and toxicity.

Rates of intestinal absorption of molybdenum in humans

The intestinal absorption of molybdenum in healthy human volunteers has been measured by simultaneous oral and intravenous administration of the stable isotopes 95Mo and 96Mo, and the results were analysed using the convolution integral technique. The results showed that molybdenum ingested in liquid form was rapidly and totally absorbed into the circulation under ordinary intake regimes. The rates and extent of absorption were lower for composite meals, and also for increasing levels of administration. This information can be helpful in the application of the new ICRP model of the human alimentary tract.

Mineral bioavailability and metabolism determined by using stable isotope tracers1

Definitive data on mineral bioavailability in humans and animals can be obtained by using isotopic tracers. The use of stable isotope tracers to study important issues in mineral nutrition has expanded rapidly in the past two decades, particularly in human nutrition studies. Stable isotopes have a number of advantages over radioisotopes. There is no exposure to radiation with stable isotopes, and some minerals have no radioisotope that can be used satisfactorily as a tracer. Multiple stable isotopes of one mineral and isotopes of multiple minerals can be administered simultaneously or sequentially. The analytical methods of choice for stable isotopes are thermal ionization mass spectrometry and inductively coupled plasma mass spectrometry (ICPMS). Thermal ionization mass spectrometry offers the greatest precision and accuracy, but it is slower, more labor intensive, and more costly than ICPMS. Bioavailability data are critical to establishing reliable dietary mineral requirements and recommendations. Combined with a computer program for compartmental modeling, mineral kinetics can be studied, including mineral turnover, pool sizes, and transfer rates between compartments. Our laboratory conducts studies using stable isotopes of Zn, Cu, Fe, Ca, Mg, and Mo. We have studied the effect of the amount of dietary intake of minerals on bioavailability and use, pregnancy and aging, and interactions among minerals. The research resulted in establishing new dietary recommendations for Cu and Mo and developing compartmental models for these minerals. Although stable isotopes have been used more extensively to date in humans than in animals, the techniques applied to humans can be used to study a number of issues important to optimizing feeding strategies for animal production.

Molybdenum kinetics in men differ during molybdenum depletion and repletion

In this study we developed an expanded compartmental model of molybdenum (Mo) kinetics to determine rates of molybdenum distribution during molybdenum depletion and repletion. The model was based on a clinical study in which 4 men consumed a low-molybdenum diet of 22 microg/d (0.23 micromol/d) for 102 d, followed by a high molybdenum diet of 467 microg/d (4.9 micromol/d) for 18 d. Stable isotopes 100Mo and 97Mo were administered orally and intravenously, respectively, at several time points during the study, and serial samples of plasma, urine, and feces were analyzed for 100Mo, 97Mo, and total Mo. Based on plasma, urine, and fecal molybdenum levels, kinetic parameters of distribution and elimination were determined. The rates of molybdenum distribution and elimination were different during depletion and repletion. During high intake, urinary molybdenum excretion was greater than during low intake. In addition, fractional tissue storage of molybdenum was lower during high intake than during low intake. This suggests that low intake results in an adaptation to conserve body Mo, and that high intake results in an adaptation to eliminate Mo. The model also suggested that food-bound molybdenum was approximately 16% less bioavailable than purified Mo. Finally, under the conditions of this study, the model suggested that an intake of 43 microg/d (0.45 micromol/d) would be sufficient to maintain plasma molybdenum levels at steady state. This is a minimum estimate because subjects in this study were in a molybdenum-sparing state. These findings provide an understanding of the adaptations in molybdenum metabolism that take place during depletion and repletion.

Molybdenum balance in healthy young Japanese women

The absorption and balance of molybdenum (Mo) were examined in 43 healthy young Japanese women in four metabolic studies performed once a year from 2001 to 2004. In each year, an 18-d metabolic study, including two successive balance study sessions of 4 d, was designed and four kinds of dietary menus were supplied to the subjects periodically. Since the protein sources of the menus were specified in 2001-2003, and soybean products were poor in 2001 and 2002 and rich in the 2003, Mo intake in 2001 and 2002 was about 150microg/d while that in 2003 reached 318microg/d. In 2004, the protein sources were not specified and Mo intake was 217microg/d. This range of Mo intake overlapped that in the Japanese population. When the results of the four studies were pooled, Mo balance was calculated as 0.09+/-0.37microg/d/kg (mean+/-SD), and no significant relationship (r=0.142) was observed between the intake and balance. Between the apparent absorption (Y) and the intake (X), a significant (r=0.988, p<0.001) positive linear regression (Y=0.927X-0.523) was observed. Similarly, a significant (r=0.960, p<0.001) positive linear regression was observed between Mo intake and urinary excretion. These results indicate that more than 90% of Mo contained in a routine dietary menu is absorbed, most of Mo absorbed is excreted in urine, and Mo balance is in equilibrium in the general Japanese population.

Plasma molybdenum reflects dietary molybdenum intake

The relationship between plasma molybdenum (Mo) and dietary intake has not been investigated in humans. We developed an isotope dilution method to determine molybdenum in 0.5 mL blood plasma by ICP-MS and conducted a study to determine the effect of dietary intake on plasma molybdenum. Twelve young men consumed a very low Mo diet (22 microg/day) for 24 days while confined to the WHNRC metabolic research unit and plasma molybdenum was monitored. (97)Mo was infused in four of the subjects (Group 1) to follow its clearance from the blood. The other eight remained in unit for 120 days (an additional 96 days). Four consumed the 22 microg/day molybdenum diet for 102 days followed by 467 microg/day for 18 days (Group 2). and four consumed five levels of dietary molybdenum for 24 days each (Group 3). (100)Mo was added to the diet one or more times at each dietary level. Total plasma molybdenum and (100)Mo were monitored throughout the study. Plasma molybdenum in the 12 subjects decreased from 8.2 +/- 0.5 to 6.1 +/- 0.5 nmol/L after 13 days of low molybdenum intake and was 5.1 +/- 0.5 nmol/L after 24 days. In Group 2, average plasma molybdenum was 7.8 +/- 0.9 nmol/L at the beginning of the study, 5.4 +/- 0.4 nmol/L during the 102 days low molybdenum period, and 16.5 +/- 0.6 nmol/L during the high molybdenum period. Plasma molybdenum in Group 3 was 4.2 +/- 2.1 nmol/L at 22 microg/day; 5.8 +/- 2.5 nmol/L at 72 microg/day; 6.6 +/- 2.3 nmol/L at 121 microg/day; 19.7 nmol/L +/-2.1 at 467 microg/day; and 43.9 +/- 2.1 nmol/L at 1490 microg/day. The results demonstrate that, in contrast to most other essential minerals, plasma molybdenum reflects low and high dietary molybdenum intakes within 14 days and may a useful indicator of low and high dietary intakes.

Nutrient requirements for preterm infant formulas

Achieving appropriate growth and nutrient accretion of preterm and low birth weight (LBW) infants is often difficult during hospitalization because of metabolic and gastrointestinal immaturity and other complicating medical conditions. Advances in the care of preterm-LBW infants, including improved nutrition, have reduced mortality rates for these infants from 9.6 to 6.2% from 1983 to 1997. The Food and Drug Administration (FDA) has responsibility for ensuring the safety and nutritional quality of infant formulas based on current scientific knowledge. Consequently, under FDA contract, an ad hoc Expert Panel was convened by the Life Sciences Research Office of the American Society for Nutritional Sciences to make recommendations for the nutrient content of formulas for preterm-LBW infants based on current scientific knowledge and expert opinion. Recommendations were developed from different criteria than that used for recommendations for term infant formula. To ensure nutrient adequacy, the Panel considered intrauterine accretion rate, organ development, factorial estimates of requirements, nutrient interactions and supplemental feeding studies. Consideration was also given to long-term developmental outcome. Some recommendations were based on current use in domestic preterm formula. Included were recommendations for nutrients not required in formula for term infants such as lactose and arginine. Recommendations, examples, and sample calculations were based on a 1000 g preterm infant consuming 120 kcal/kg and 150 mL/d of an 810 kcal/L formula. A summary of recommendations for energy and 45 nutrient components of enteral formulas for preterm-LBW infants are presented. Recommendations for five nutrient:nutrient ratios are also presented. In addition, critical areas for future research on the nutritional requirements specific for preterm-LBW infants are identified.

Molybdenum metabolism: stable isotope studies in infancy

The essential trace element molybdenum (Mo) is bound to and required for the function of molybdoenzymes, e.g. sulfite and xanthine oxidase. Dietary recommendations for early infancy are based on limited knowledge about its metabolism. 100Mo was used as an extrinsic tag to study the absorption and kinetics of excretion in infancy. 10 infants with a gestational age of 35 (30-39) weeks, a birth weight of 2.0 (0.9-2.3) kg and a post-natal age of 20 (10-54) days were studied. They received 25 microg 100Mo/kg with a feed of human milk or formula. Fractional urinary and fecal collections were conducted preceding the 100Mo intake and for 48-72 hours afterwards. The materials were analyzed by atomic absorption spectroscopy and inductively coupled plasma mass spectrometry. The median absorption of 100Mo intake was 97.5 (96.3 to 99.1) %. The retention of nutritive Mo intake and 100Mo in the study period was 11.2 (3.8-15.7) microg Mo/kg, equivalent to 35.7 (12.7-55.6) %. The Mo concentration increased to a peak value in urine within 8 (6-13) hours and in feces within 24 (7-48.5) hours. In addition, increases of copper in feces and urine were observed in 8 of 9 infants studied. Mo given orally is well resorbed in premature infants, and predominantly excreted in the urine. Dietary recommendations should prevent excessive intakes in infancy.