Molybdenum - a scoping review for Nordic Nutrition Recommendations 2023

Molybdenum is an essential element in the form of the molybdenum cofactor (Moco). In humans, Moco is required for four enzymes: xanthine oxidase (XO), aldehyde oxidase, sulfite oxidase (SO), and mitochondrial amidoxime-reducing component (mARC). The enzymes are involved in the oxidation of purines to uric acid, metabolism of aromatic aldehydes and heterocyclic compounds, and in the catabolism of sulfur amino acids. Molybdenum cofactor deficiency is a rare autosomal recessive syndrome due to a defective synthesis of Moco, resulting in a deficiency of all the molybdoenzymes. There are no reports on clinical signs of dietary molybdenum deficiency in otherwise healthy humans. Water-soluble molybdate is efficiently absorbed from the digestive tract. The body retention is regulated by urinary excretion. Plasma molybdenum reflects long-term intake and 24-h urinary excretion is related to recent intake. There are no biochemical markers of molybdenum status. Cereal products are the main contributors to molybdenum dietary intake, estimated to 100-170 mu g/day in Nordic studies. Little data are available on molybdenum toxicity in humans. A tolerable upper intake level of molybdenum has been based on reproductive toxicity in rats, but the effects have not been reproduced in more recent studies. The U.S. Institute of Medicine (IOM, present National Academy of Sciences, Engineering, and Medicine; NASEM) established a Recommended Dietary Allowance of 45 mu g/day in adult men and women in 2001, based on a small study reporting urinary excretion in balance with intake at 22 mu g/day. The European Food Safety Authority (EFSA) considered in 2013 the evidence to be insufficient to derive an Average Requirement and a Population Reference Intake, but proposed an Adequate Intake of 65 mu g/day for adults

Vitamin D receptor antagonist activity in wastewater effluents-potential for endocrine disruption

Background Endocrine disrupting chemicals have been identified for a number of human endocrine systems, but there are no reports on vitamin D-antagonistic activities in environmental samples.Objectives We have investigated if there are compounds present in the environment that can act as Vitamin D receptor (VDR) antagonists.Methods Water samples were collected of the influent and effluent water from five Swedish wastewater treatment facilities and concentrated with solid phase extraction. VDR antagonistic properties of the samples were tested with a cell-based in vitro assay responsive to vitamin D signaling. Cytotoxicity was monitored by three different assays.Results We observed a dose-dependent decrease in the VDR signaling in most studied samples, although the effect was overlapping with cytotoxicity for the influent samples. For effluent samples, we observed clear VDR antagonistic effects also in non-cytotoxic concentrations. The observed effects could not be explained by presence of natural organic matter or cadmium in the water.Discussion The vitamin D endocrine system regulates a broad range of physiological processes, and disruption of this system could be associated with serious health consequences. In this study, we report environmental presence of compounds with VDR antagonistic properties, compounds which constitute a new group of potential endocrine disruptors. The VDR antagonism was observed in wastewater treatment facility effluent waters, which are discharged into water systems used as raw water for drinking water production. The findings reported in this study may indicate a potential hazard to human health and aquatic life. Future research is needed to investigate the presence of VDR antagonists in the environment, identification of the causative compounds, and studies of exposure of humans and aquatic organisms to these compounds

Antiandrogenic activity and bioavailability of magnolol analogs – A potential for prostate cancer therapeutics

Background: Prostate cancer is the second most common form of cancer in men worldwide and there is a great need for novel treatment strategies, especially for castrate-resistant prostate cancers where the proliferation of the cancer cells is stimulated by androgens produced in the adrenal cortex and the cancer cells. Purpose: In this study, we have investigated the antiandrogenic properties of magnolol and ten synthetic analogs in vitro. Study design and methods: The compounds were evaluated for cytotoxicity, antiandrogenic receptor activity, binding to the androgen receptor, effects on the production of Prostate-specific antigen (PSA), and potential to pass over a tight layer of Caco-2 cells mimicking gastrointestinal absorption. Results: We found that almost all investigated compounds were antiandrogenic in an androgen receptor reporter gene assay, with IC50 values ranging from 7 to 86 µM. Magnolol itself had the highest antiandrogenic potency. Five of the compounds were then evaluated for their binding to the androgen receptor and three of these compounds were found to bind to the receptor. These five compounds were also evaluated for their effect on the PSA production and four were found to decrease PSA production at non-cytotoxic concentrations. The antiandrogenic activity after passage through a layer of Caco-2 cells, mimicking gastrointestinal absorption, was also evaluated for three of the compounds. All three compounds were found to have the capacity to be transported from the apical to the basolateral side of the Caco-2 cell layer and exert antiandrogenic effects after the transport. Conclusion: In conclusion, this study shows that magnolol and analogs have antiandrogenic effects in vitro and that selected analogs can pass over a tight layer of Caco-2 cells, indicating a potential for good bioavailability after oral administration. These magnolol analogs thereby constitute an interesting group of compounds worthy of further evaluation as potential anti-prostate cancer therapeutics

A model of secreting murine mammary epithelial HC11 cells comprising endogenous Bcrp/Abcg2 expression and function

Breast cancer resistance protein (Bcrp/Abcg2) and multidrug transporter 1 (Mdr1/Abcb1) are efflux proteins located in the apical membrane of mammary epithelial cells (MEC). Bcrp is induced in MEC during gestation and lactation, while Mdr1 is down-regulated during lactation. Numerous drugs and toxic compounds are known to be actively secreted into milk by Bcrp, but most chemicals have not been investigated in this respect, emphasizing the need for functional Bcrp studies in an established cell line with secreting mammary epithelial cells. The present study was undertaken to examine expressions of Bcrp and Mdr1 in mammary epithelial HC11 cells, derived from a mid-gestational murine mammary gland. In addition, Bcrp function was assessed by transport experiments with mitoxantrone (MX) in undifferentiated HC11 cells, in HC11 cells subjected to Bcrp RNA interference (RNAi) as well as in HC11 cells stimulated to differentiate by treatment with lactogenic hormones. Differentiated HC11 cells organized into alveolar-resembling structures and gene expression of the major milk protein B-casein was induced, whereas undifferentiated cells formed monolayers with lower B-casein expression. Bcrp and Mdr1 gene and protein were expressed in both undifferentiated and differentiated HC11 cells. Differentiation of HC11 cells resulted in increased Bcrp protein expression, while Mdr1 gene and protein expressions were reduced. The Bcrp inhibitor elacridar (GF120918) reduced secretion and increased accumulation of MX in both undifferentiated and differentiated HC11 cells. Silencing of the Bcrp gene caused an increased accumulation of MX. The results indicate that the HC11 cell model provides a promising tool to investigate transport of potential Bcrp substrates in mammary epithelial cells

Impact of sample acidification and extract storage on hormone receptor-mediated and oxidative stress activities in wastewater

An underemphasized aspect of sampling strategies in effect-based in vitro testing is to determine suitable collection and preparation techniques. In the current study, the impact of sample acidification on bioactivities was assessed using in vitro bioassays for hormone receptor-mediated effects (estrogen receptor [ER] and androgen receptor [AR]) and the oxidative stress response (Nrf2 activity). Sampling was conducted at a recently upgraded Swedish wastewater treatment plant. Future plans for the treated wastewater include reuse for irrigation or as a drinking water source. In the AR and Nrf2 assays, acidification decreased bioactivities in the wastewater influent sample extracts, whereas acidification increased bioactivities following further treatment (disc filtration). In the ER assay, acidification had no impact on the observed bioactivities in the sample extracts. A secondary objective of the study was to assess the stability of the sample extracts over time. Lower activities were detected in the ER and AR assays in all extracts after storage for approximately 1 year. Nrf2 activities did not decrease over time, but rather increased in some of the acidified sample extracts. Overall, the findings suggest that sampling strategies involving acidification may need to be tailored depending on the selected bioassay(s) and the type of wastewater treatments being assessed

An in vitro-based hazard assessment of liquid smoke food flavourings

Liquid smoke products are widely used as a food additive to create a desired smoke flavour. These products may contain hazardous chemicals generated during the wood-burning process. However, the toxic effects of these types of hazardous chemicals constituting in the commercially available products are largely unknown. Therefore, a test battery of cell-based in vitro methods, covering different modes of actions of high relevance to human health, was applied to study liquid smoke products. Ten liquid smoke flavourings were tested as non-extracted and extracted. To assess the potential drivers of toxicity, we used two different solvents. The battery of in vitro methods covered estrogenicity, androgenicity, oxidative stress, aryl hydrocarbon receptor activity and genotoxicity. The non-extracted samples were tested at concentrations 0.002 to 1 mu L liquid smoke flavouring/mL culture medium, while extracted samples were tested from 0.003 to 200 mu L/mL. Genotoxicity was observed for nearly all non-extracted and all hexane-extracted samples, in which the former had higher potency. No genotoxicity was observed for ethyl acetate-extracted samples. Oxidative stress was activated by almost all extracted and non-extracted samples, while approximately half of the samples had aryl hydrocarbon receptor and estrogen receptor activities. This study used effect-based methods to evaluate the complex mixtures of liquid smoke flavourings. The increased bioactivities seen upon extractions indicate that non-polar chemicals are driving the genotoxicity, while polar substances are increasing oxidative stress and cytotoxic responses. The differences in responses indicate that non-extracted products contain chemicals that are able to antagonize toxic effects, and upon extraction, the protective substances are lost

Artificial infiltration in drinking water production: Addressing chemical hazards using effect-based methods

Artificial infiltration is an established managed aquifer recharge method that is commonly incorporated into drinking water processes. However, groundwater sourced from this type of purification method is prone to contamination with chemical hazards. Such an instance was previously shown at a Swedish DWTP where the river water was contaminated by hazardous chemicals during artificial infiltration. Further, there remains a paucity of research studying the quality of drinking water following this type of treatment from an effect-based bioanalytical perspective. In the current study, an effect-based assessment for chemical hazards was conducted for a Swedish drinking water system comprised of two DWTPs fed artificially-infiltrated river water. In this system, artificial infiltration of the river water takes approximately six to eight months. A sampling event was conducted in the autumn season and the samples were enriched by solid phase extraction. A panel of cell-based reporter gene assays representing several toxicity pathways was selected: oxidative stress response (Nrf2 activity), aryl hydrocarbon receptor (AhR) activation, and hormone receptor-mediated effects (estrogen receptor [ER], androgen receptor [AR]). AhR and ER bioactivities were detected in samples collected from the river intake and in the open-air infiltration basins prior to artificial infiltration. However, the AhR activity decreased and ER activity was effectively removed following artificial infiltration. In the Nrf2 and AR assays, no bioactivities above cut-off levels were detected in any samples collected along the entire treatment process of the drinking water production from source to tap. Using a suite of bioassays, the current study highlighted the effectiveness of artificial infiltration in reducing bioactive compounds in this raw river water. Although artificial infiltration is a common purification method in drinking water production, the limited number of effect-based studies evaluating the effectiveness of this method emphasizes the need for further research to better understand the risks and benefits of this water treatment process

Cadmium in blood and urine--impact of sex, age, dietary intake, iron status, and former smoking--association of renal effects.

We studied determinants of cadmium status and kidney function in nonsmoking men and women living on farms in southern Sweden. Median blood Cd (BCd) was 1.8 nmol/L (range, 0.38-18) and median urinary Cd (UCd) was 0.23 nmol/mmol creatinine (range, 0.065-0.99). The intake of Cd per kilogram body weight did not significantly differ between sexes and did not correlate with BCd or UCd, which may be explained by a low and varying bioavailibility of Cd from food items. However, when a subgroup of the study population, couples of never-smoking men and women, were compared, a lower intake per kilogram body weight was found in the women, but the women had a 1.8 times higher BCd and a 1.4 times higher UCd. The higher female BCd and UCd may be explained by higher absorption due to low iron status. BCd and UCd both increased with age and were higher in the ex-smokers, who had stopped smoking more than 5 years before the study, compared to never-smokers. The contribution of locally produced food to the total Cd intake was relatively low and varied. Males living in areas with low soil Cd had lower UCd than the others. However, Cd levels in kidneys from pigs, fed locally produced cereals, did not predict BCd or UCd in humans at the same farms. The kidney function parameter ss2-microglobulin-creatinine clearance was related to UCd, whereas urinary protein-HC, N-acetyl-ss-glucoseaminidase or albumin-creatinine clearance was not when age was accounted for. Hence, even at the low exposure levels in this study population, there was an indication of effect on biochemical markers of renal function