Hair Mn Levels Research Articles

A Review on the Environmental Exposure to Airborne Manganese, Biomonitoring, and Neurological/Neuropsychological Outcomes.

The occupational exposure to airborne manganese (Mn) has been linked for decades with neurological effects. With respect to its environmental exposure, the first reviews on this matter stated that the risk posed to human health by this kind of exposure was still unknown. Later, many studies have been developed to analyze the association between environmental Mn exposure and health effects, most of them including the measure of Mn in selected human biomarkers. This review aims at collecting and organizing the literature dealing with the environmental airborne Mn exposure (other routes of exposure were intentionally removed from this review), the biomonitoring of this metal in different body matrices (e.g., blood, urine, nails, hair), and the association between exposure and several adverse health effects, such as, e.g., neurocognitive, neurodevelopmental, or neurobehavioral outcomes. From the different exposure routes, inhalation was the only one considered in this review, to take into account the areas influenced by industrial activities closely related to the Mn industry (ferromanganese and silicomanganese plants, Mn ore mines, and their processing plants) and by traffic in countries where a fuel additive, methylcyclopentadienyl manganese tricarbonyl (MMT), has been used for years. In these areas, high air Mn levels have been reported in comparison with the annual Reference Concentration (RfC) given by the US EPA for Mn, 50ng/m3. This review was performed using Scopus and MEDLINE databases with a keyword search strategy that took into account that each valid reference should include at least participants that were exposed to environmental airborne Mn and that were subjected to analysis of Mn in biomarkers or subjected to neurological/neuropsychological tests or both. Overall, 47 references matching these criteria were included in the discussion. Most of them report the measure of Mn in selected biomarkers (N=43) and the assessment of different neurological outcomes (N=31). A negative association is usually obtained between Mn levels in hair and some neurological outcomes, such as cognitive, motor, olfactory, and emotional functions, but not always significant. However, other biomarkers, such as blood and urine, do not seem to reflect the chronic environmental exposure to low/moderate levels of airborne Mn. Further studies combining the determination of the Mn exposure through environmental airborne sources and biomarkers of exposure and the evaluation of at least cognitive and motor functions are needed to better understand the effects of chronic non-occupational exposure to airborne Mn.

ВЗАИМОСВЯЗИ ОБМЕНА ЭССЕНЦИАЛЬНЫХ МИКРОЭЛЕМЕНТОВ И ФУНКЦИОНАЛЬНОГО СОСТОЯНИЯ СЕРДЕЧНО-СОСУДИСТОЙ СИСТЕМЫ У СТУДЕНТОВ-ИНОСТРАНЦЕВ

The aim of the study was to study the relationship between the level of essential trace elements and the functional state of the cardiovascular system (CVS) in freshmen from foreign countries compared with freshmen from Russia (control group). The CVS study was conducted by the AngioScan-01 hardware-software complex (AIC). The level of essential elements in the analyzed biosubstrates was determined by inductively coupled plasma mass spectrometry (ICP-MS). It was found that foreign students have significantly higher values of the stress index (IS) and vascular wall stiffness (SI) compared to freshmen from Russia. At the same time, the value of the reflection index (RI is a marker of peripheral vascular tone) and the integral indicator indicating aortic elasticity (dTpp) in foreign students were significantly lower than those of freshmen from Russia. Analysis of hair trace element content revealed significantly lower hair Co, Cr, Cu, Fe, I, Mg, Mn, and V levels in international students as compared to controls. Urinary trace element levels were more stable. Particularly, Co and Mn levels were found to be lower, whereas Cu and Zn concentration was higher than those in students from Russia. Correlation analysis revealed inverse association between stress index and hair Fe content. Mg and Mn levels in hair were also inversely associated with stiffness index. Urinary Cu, Se, and Zn concentration directly correlated with arterial stiffness, being inversely associated with dTpp values. Oppositely, urinary V levels were inversely and directly correlated with these parameters, respectively. Therefore, the results of analysis demonstrated the potential relationship between patterns of trace element status and cardiovascular reactivity in international students.

Manganese levels and hepatocellular carcinoma: A systematic review and meta-analysis based on Asian cohort.

Several studies have investigated the relationship between Manganese (Mn) levels and hepatocellular carcinoma (HCC), but the results were inconsistent. Thus, we conducted a systematic review and meta-analysis to evaluate the association between Mn levels and HCC. Nine studies focusing on hair Mn levels, 6 studies on serum Mn levels and 6 studies on tissue Mn levels were identified in a systematic search of PubMed, CNKI, Wanfang and SinoMed databases. Standard mean differences (SMD) with the corresponding 95% confidence intervals (CI) were pooled to compare the Mn levels between HCC and controls. In serum, the Mn levels in HCC were significantly lower than in healthy controls (SMD (95% CI): −0.941 (−1.559, −0.323)). In hair, the Mn levels in HCC were slightly lower than in healthy controls, but not significant (SMD (95% CI): −0.168 (−0.766, 0.430)). In tissue, the Mn levels in tumors were significantly lower than in adjacent normal tissues (SMD (95% CI): −4.867 (−7.143, −2.592)). Subgroup analysis showed consistent results. In conclusion, this meta-analysis suggested an inverse association between Mn levels and HCC.

Associations Between Hair Manganese Levels and Cognitive, Language, and Motor Development in Preschool Children from Montevideo, Uruguay

ABSTRACT Environmental manganese (Mn) exposure in childhood has been associated with developmental deficits. This study investigated associations between low-level Mn exposure and developmental scores in children aged 14–45 months. Children's hair samples (n = 60) were analyzed for Mn and lead (Pb) using inductively coupled plasma mass spectrometry (ICP-MS). Children were assessed with the Bayley Scales of Infant Development III (BSID). Mean hair Mn and Pb concentrations were 0.98 ± 0.74 and 10.1 ± 10.5 μg/g, respectively. Unadjusted inverse associations were seen between Mn and BSID subscales, with girls having lower scores related to Mn than boys. No significant associations remained in covariate-adjusted models, although when stratified by sex boys had a positive association between hair Mn levels and language scores. This study does not show clear evidence of an association between hair Mn concentrations and children's developmental scores in a region of low-level Mn exposure.

Hair as a Biomarker of Environmental Manganese Exposure

The absence of well-validated biomarkers of manganese (Mn) exposure in children remains a major obstacle for studies of Mn toxicity. We developed a hair cleaning methodology to establish the utility of hair as an exposure biomarker for Mn and other metals (Pb, Cr, Cu), using ICPMS, scanning electron microscopy, and laser ablation ICPMS to evaluate cleaning efficacy. Exogenous metal contamination on hair that was untreated or intentionally contaminated with dust or Mn-contaminated water was effectively removed using a cleaning method of 0.5%Triton X-100 sonication plus 1 N nitric acid sonication. This cleaning method was then used on hair samples from children (n = 121) in an ongoing study of environmental Mn exposure and related health effects. Mean hair Mn levels were 0.121 μg/g (median = 0.073 μg/g, range = 0.011-0.736 μg/g), which are ∼4 to 70-fold lower than levels reported in other pediatric Mn studies. Hair Mn levels were also significantly higher in children living in the vicinity of active, but not historic, ferroalloy plant emissions compared to controls (P < 0.001). These data show that hair can be effectively cleaned of exogenous metal contamination, and they substantiate the use of hair Mn levels as a biomarker of environmental Mn exposure in children.

Do breastfed and formula‐fed infants differ on hair manganese levels?

Manganese (Mn) toxicity is observed in children exposed to high Mn levels in water and in total parenteral nutrition. Infant formula contains 5–28 times as much Mn as breast milk, but is not widely studied as a source of Mn toxicity. The objective of this study is to determine the difference in hair Mn levels between infants who are predominantly formula‐fed (FF) or breast‐fed (BF), and explore other salient predictors of hair Mn levels. Infants 3–6 mo who were FF (n=5) or BF (n=30) were recruited. Water and hair Mn levels for mother and infant were determined by ICP‐MS analysis. Mean±SD (median) hair Mn for BF and FF infants was 2.21±2.77 (1.45) μg/mL and 2.76±1.80 (3.16) μg/mL, respectively. Group medians differed significantly (p=0.002). 50.0% of FF displayed elevated hair Mn levels (&gt;3 μg/g), compared to 13.8% of BF infants. Mean water Mn concentration was 0.92±2.10 ng/mL for BF and 0.21±0.16 ng/mL for FF infants. Infant hair Mn was not correlated with water Mn concentration (p=0.32), sex (p=0.21) or age (p=0.25). Additional samples are being collected to provide more definitive results.

Effect of High Dietary Manganese Intake of Neonatal Rats on Tissue Mineral Accumulation, Striatal Dopamine Levels, and Neurodevelopmental Status

Mn is an essential element, but may become neurotoxic at high levels. Recent reports of high Mn levels in hair of children with neurodevelopmental deficits suggest that these deficits could be due to Mn-induced neurotoxic effects on brain dopamine (DA) systems, although the mechanism is not well understood. Infant formulas contain considerably higher concentrations of Mn than human milk. Thus, formula-fed infants are exposed to high levels of Mn at a time when Mn homeostasis is incompletely developed. We studied the effects of dietary Mn supplementation of rat pups on tissue Mn accumulation, brain dopamine levels, infant neurodevelopmental status, and behavior at maturity. Newborn rats were supplemented daily with 0, 50, 250, or 500 μg Mn given orally from day 1 to day 20. Mineral analysis of small intestine and brain at day 14 showed a significant increase of tissue Mn in supplemented rats. Neurodevelopmental tests conducted at various ages showed significant delays as a function of Mn supplementation. At day 32, there was a significant positive relationship between passive avoidance errors and Mn supplementation levels. Brains of animals killed on day 40 showed a significant inverse relationship between Mn supplementation level and striatal dopamine concentration. These observations suggest that dietary exposure to high levels of Mn during infancy can be neurotoxic to rat pups and result in developmental deficits.

Hair manganese concentrations in newborns and their mothers

The study was designed to investigate the manganese (Mn) status of mothers and their offspring at delivery. Hair Mn concentrations in 31 full-term, 18 preterm and 12 newborn infants with congenital malformations and their mothers were determined by the flameless atomic absorption technique. Both in infants with congenital malformations and their mothers, hair Mn levels were significantly lower than the full-term and preterm infant-mother pairs. With the exception of mothers of infants with congenital malformations, hair Mn concentrations in mothers were significantly higher as compared with their infants. Low hair Mn concentrations of infants with congenital malformations and their mothers may possibly reflect a state of Mn deficiency in these women. These results imply that 1) Mn deficiency may play a role as one potential factor in intrauterine malformations, 2) Mn is supplied to the fetus by a homeostatic mechanism which is mainly dependent on the Mn status of the mother, 3) prenatal Mn analysis in maternal hair may prove to be a reliable indicator for the risk of intrauterine malformations.