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Metal Ions in Life Sciences Jan 2019Manganese is an essential dietary element that functions primarily as a coenzyme in several biological processes. These processes include, but are not limited to,... (Review)
Review
Manganese is an essential dietary element that functions primarily as a coenzyme in several biological processes. These processes include, but are not limited to, macronutrient metabolism, bone formation, free radical defense systems, and in the brain, ammonia clearance and neurotransmitter synthesis. It is a critical component in dozens of proteins and enzymes, and is found in all tissues. Concentrated levels of Mn are found in tissues rich in mitochondria and melanin, with both, liver, and pancreas having the highest concentrations under normal conditions. However, overexposure to environmental Mn via industrial occupation or contaminated drinking water can lead to toxic brain Mn accumulation that has been associated with neurological impairment. The objective of this chapter is to address the biological importance of Mn (essentiality), routes of exposure, factors dictating Mn status, a brief discussion of Mn neurotoxicity, and proposed methods for neurotoxicity remediation.
Topics: Brain Chemistry; Humans; Manganese
PubMed: 30855111
DOI: 10.1515/9783110527872-016 -
International Journal of Molecular... Oct 2023Manganese (Mn) is an essential trace element with unique functions in the body; it acts as a cofactor for many enzymes involved in energy metabolism, the endogenous... (Review)
Review
Manganese (Mn) is an essential trace element with unique functions in the body; it acts as a cofactor for many enzymes involved in energy metabolism, the endogenous antioxidant enzyme systems, neurotransmitter production, and the regulation of reproductive hormones. However, overexposure to Mn is toxic, particularly to the central nervous system (CNS) due to it causing the progressive destruction of nerve cells. Exposure to manganese is widespread and occurs by inhalation, ingestion, or dermal contact. Associations have been observed between Mn accumulation and neurodegenerative diseases such as manganism, Alzheimer's disease, Parkinson's disease, Huntington's disease, and amyotrophic lateral sclerosis. People with genetic diseases associated with a mutation in the gene associated with impaired Mn excretion, kidney disease, iron deficiency, or a vegetarian diet are at particular risk of excessive exposure to Mn. This review has collected data on the current knowledge of the source of Mn exposure, the experimental data supporting the dispersive accumulation of Mn in the brain, the controversies surrounding the reference values of biomarkers related to Mn status in different matrices, and the competitiveness of Mn with other metals, such as iron (Fe), magnesium (Mg), zinc (Zn), copper (Cu), lead (Pb), calcium (Ca). The disturbed homeostasis of Mn in the body has been connected with susceptibility to neurodegenerative diseases, fertility, and infectious diseases. The current evidence on the involvement of Mn in metabolic diseases, such as type 2 diabetes mellitus/insulin resistance, osteoporosis, obesity, atherosclerosis, and non-alcoholic fatty liver disease, was collected and discussed.
Topics: Humans; Manganese; Diabetes Mellitus, Type 2; Manganese Poisoning; Homeostasis; Neurodegenerative Diseases
PubMed: 37834407
DOI: 10.3390/ijms241914959 -
Current Environmental Health Reports Sep 2015Exposure to manganese (Mn) causes clinical signs and symptoms resembling, but not identical to, Parkinson's disease. Since our last review on this subject in 2004, the... (Review)
Review
Exposure to manganese (Mn) causes clinical signs and symptoms resembling, but not identical to, Parkinson's disease. Since our last review on this subject in 2004, the past decade has been a thriving period in the history of Mn research. This report provides a comprehensive review on new knowledge gained in the Mn research field. Emerging data suggest that beyond traditionally recognized occupational manganism, Mn exposures and the ensuing toxicities occur in a variety of environmental settings, nutritional sources, contaminated foods, infant formulas, and water, soil, and air with natural or man-made contaminations. Upon fast absorption into the body via oral and inhalation exposures, Mn has a relatively short half-life in blood, yet fairly long half-lives in tissues. Recent data suggest Mn accumulates substantially in bone, with a half-life of about 8-9 years expected in human bones. Mn toxicity has been associated with dopaminergic dysfunction by recent neurochemical analyses and synchrotron X-ray fluorescent imaging studies. Evidence from humans indicates that individual factors such as age, gender, ethnicity, genetics, and pre-existing medical conditions can have profound impacts on Mn toxicities. In addition to body fluid-based biomarkers, new approaches in searching biomarkers of Mn exposure include Mn levels in toenails, non-invasive measurement of Mn in bone, and functional alteration assessments. Comments and recommendations are also provided with regard to the diagnosis of Mn intoxication and clinical intervention. Finally, several hot and promising research areas in the next decade are discussed.
Topics: Absorption, Physiological; Adult; Biomarkers; Environmental Exposure; Female; Half-Life; Humans; Infant; Infant Mortality; Infant, Newborn; Inhalation Exposure; Male; Manganese; Risk Assessment
PubMed: 26231508
DOI: 10.1007/s40572-015-0056-x -
Chemical Society Reviews Jun 2022The emerging field of organometallic catalysis has shifted towards research on Earth-abundant transition metals due to their ready availability, economic advantage, and... (Review)
Review
The emerging field of organometallic catalysis has shifted towards research on Earth-abundant transition metals due to their ready availability, economic advantage, and novel properties. In this case, manganese, the third most abundant transition-metal in the Earth's crust, has emerged as one of the leading competitors. Accordingly, a large number of molecularly-defined Mn-complexes has been synthesized and employed for hydrogenation, dehydrogenation, and hydroelementation reactions. In this regard, catalyst design is based on three pillars, namely, metal-ligand bifunctionality, ligand hemilability, and redox activity. Indeed, the developed catalysts not only differ in the number of chelating atoms they possess but also their working principles, thereby leading to different turnover numbers for product molecules. Hence, the critical assessment of molecularly defined manganese catalysts in terms of chelating atoms, reaction conditions, mechanistic pathway, and product turnover number is significant. Herein, we analyze manganese complexes for their catalytic activity, versatility to allow multiple transformations and their routes to convert substrates to target molecules. This article will also be helpful to get significant insight into ligand design, thereby aiding catalysis design.
Topics: Catalysis; Hydrogenation; Ligands; Manganese
PubMed: 35583150
DOI: 10.1039/d2cs00093h -
Animal Reproduction Science Mar 2022Manganese (Mn) is the twelfth most abundant element in the earth's crust and is widely distributed throughout the surface of the planet, naturally occurring in rocks,... (Review)
Review
Manganese (Mn) is the twelfth most abundant element in the earth's crust and is widely distributed throughout the surface of the planet, naturally occurring in rocks, soil, water, and food. As an essential trace mineral in diets, Mn is required for a variety of metabolic functions including skeletal system development, energy metabolism, enzyme activation, nervous system function, immune system function, and reproductive hormone function. Manganese has effects on reproductive hormone function as a cofactor for enzymes necessary for cholesterol synthesis. Production of steroid hormones necessary for reproduction is dependent on the availability of cholesterol as a precursor. There is also evidence that Mn has effects on reproduction due to actions at the hypothalamus. Because Mn is used for manufacturing of steel, recent research has focused on the effects of Mn toxicity as a result of occupational endeavors rather than evaluating the optimal Mn inclusion rate for mammalian growth and development, reproductive function, immune function, etc. The objective of this review is to address the functions of Mn in reproduction of animals but there is also a focus on other areas of mammalian biology affected by Mn functions, with an emphasis on domestic swine (Sus scrofa).
Topics: Animals; Diet; Hypothalamus; Manganese; Reproduction; Trace Elements
PubMed: 35121412
DOI: 10.1016/j.anireprosci.2022.106924 -
Free Radical Biology & Medicine Aug 2019Throughout the history of life on Earth, abiotic components of the environment have shaped the evolution of life, and in turn life has shaped the environment. The... (Review)
Review
Throughout the history of life on Earth, abiotic components of the environment have shaped the evolution of life, and in turn life has shaped the environment. The element manganese embodies a special aspect of this collaboration; its history is closely entwined with those of photosynthesis and O-two reigning features that characterize the biosphere today. Manganese chemistry was central to the environmental context and evolutionary innovations that enabled the origin of oxygenic photosynthesis and the ensuing rise of O. It was also manganese chemistry that provided an early, fortuitous antioxidant system that was instrumental in how life came to cope with oxidative stress and ultimately thrive in an aerobic world. Subsequently, the presence of O transformed the biogeochemical dynamics of the manganese cycle, enabling a rich suite of environmental and biological processes involving high-valent manganese and manganese redox cycling. Here, we describe insights from chemistry, biology, and geology, to examine manganese dynamics in the environment, and its unique role in the history of life.
Topics: Biological Evolution; Earth, Planet; Manganese; Oxidation-Reduction; Oxygen; Photosynthesis
PubMed: 30738765
DOI: 10.1016/j.freeradbiomed.2019.01.036 -
Critical Reviews in Toxicology Sep 2022Long-term inhalation exposure to manganese (Mn) metal or its inorganic compounds can result in manganism or subclinical neurofunctional deficits. Studies have described... (Review)
Review
Long-term inhalation exposure to manganese (Mn) metal or its inorganic compounds can result in manganism or subclinical neurofunctional deficits. Studies have described affected workers in Mn dioxide mining, Mn-containing ore crushing and milling facilities, manufacturing of dry-cell batteries, Mn steel and alloy production plants, and in welders. The objective of this study was to critically review existing evidence on the reliability of potential biomarkers of Mn exposure, specifically the relationship between inhalation exposure to Mn particulates in different occupational settings and Mn concentrations in blood and other biological fluids and tissues, with a particular focus on whole blood as a potentially useful medium for measuring internal tissue dose. We also examined available evidence on the relationship between Mn levels in blood and adverse clinical and subclinical neurotoxic outcomes. Three bibliographic databases were searched for relevant studies and identified references were screened by two independent reviewers. Of the 6338 unique references identified, 76 articles were retained for data abstraction. Findings indicate that the relationships between Mn in blood and both external Mn exposure indices and neurofunctional impairments are limited and inconsistent. Different sources of exposure to Mn compounds, heterogeneity in the methodological approaches, and inadequate reporting of essential information limited direct comparison of the reported findings. Among the Mn-exposure biomarkers considered in this review - including biomarkers in blood, plasma, serum, erythrocytes, urine, bone, toenails, fingernails, hair, saliva - biomarkers in whole blood may provide to be most useful in Mn biomonitoring and risk assessment.
Topics: Humans; Manganese; Reproducibility of Results; Occupational Exposure; Metals; Biomarkers
PubMed: 36705643
DOI: 10.1080/10408444.2022.2128718 -
Advances in Nutrition (Bethesda, Md.) May 2017
Topics: Deficiency Diseases; Environmental Exposure; Humans; Manganese
PubMed: 28507016
DOI: 10.3945/an.117.015305 -
Nutrition in Clinical Practice :... Jun 2018Manganese (Mn) is an essential micronutrient required for the activity of metalloenzymes. It is an essential component of parenteral nutrition (PN), but requirements are... (Review)
Review
Manganese (Mn) is an essential micronutrient required for the activity of metalloenzymes. It is an essential component of parenteral nutrition (PN), but requirements are low. Mn status is difficult to assess, with the commonest method being measurement of its concentration in whole blood. This method has limitations, including artifactually high concentrations resulting from contamination of specimen tubes. Mn toxicity is a well-recognized complication of PN, the risk of which increases if there is cholestasis or if the patient has received high doses. It usually presents with parkinsonian-like symptoms but may be detected presymptomatically as hypermanganesemia or as increased signal intensity of the basal ganglia upon T1-weighted magnetic resonance imaging. Caution is necessary when providing Mn for patients on long-term PN (>1 month). It is advisable to withhold supplementation if hypermanganesemia or cholestasis develops. Deficiency of Mn is rare in patients treated with PN. PN regimens are contaminated with Mn in amounts likely to meet requirements. Consequently, it is debated whether PN should be routinely supplemented with Mn. The currently recommended dose of Mn in adults treated with PN is 55 μg/d, but the doses provided by most currently available multi-trace element products exceed this. In response to calls for new products to be developed, 2 new multi-trace element products are currently available in Europe that provide Mn doses of 55 μg/d. Once these products are in general use, it is likely that the incidence of Mn toxicity will decrease.
Topics: Biomarkers; Cholestasis; Dose-Response Relationship, Drug; Humans; Magnetic Resonance Imaging; Manganese; Nutritional Status; Parenteral Nutrition; Risk Factors
PubMed: 28445108
DOI: 10.1177/0884533617702837 -
Journal of Agricultural and Food... Nov 2020Manganese (Mn) is an essential element that participates in several biological processes. Mn serves as a cofactor for several enzymes, such as glutamine synthetase and... (Review)
Review
Manganese (Mn) is an essential element that participates in several biological processes. Mn serves as a cofactor for several enzymes, such as glutamine synthetase and oxidoreductases, that have an important role in the defense of the organisms against oxidative stress. The diet is the main source of Mn intake for humans, and adequate daily intake levels for this metal change with age. Moreover, in higher amounts, Mn may be toxic, mainly to the brain. Here, we provide an overview of Mn occurrence in food, addressing its bioaccessibility and discussing the dietary standard and recommended intake of Mn consumption. In addition, we review some mechanisms underlying Mn-induced neurotoxicity.
Topics: Animals; Biological Availability; Brain; Diet; Humans; Manganese
PubMed: 32298096
DOI: 10.1021/acs.jafc.0c00641