Trace element biology: the knowledge base and its application for the nutrition of individuals and populations

Diabetic Neuropathy of the Retina and Inflammation: Perspectives

A clear connection exists between diabetes and atherosclerotic cardiovascular disease. Consequently, therapeutic approaches that target both diseases are needed. Clinical trials are currently underway to explore the roles of obesity, adipose tissue, gut microbiota, and pancreatic beta cell function in diabetes. Inflammation plays a key role in diabetes pathophysiology and associated metabolic disorders; thus, interest has increased in targeting inflammation to prevent and control diabetes. Diabetic retinopathy is known as a neurodegenerative and vascular disease that occurs after some years of poorly controlled diabetes. However, increasing evidence points to inflammation as a key figure in diabetes-associated retinal complications. Interconnected molecular pathways, such as oxidative stress, and the formation of advanced glycation end-products, are known to contribute to the inflammatory response. This review describes the possible mechanisms of the metabolic changes in diabetes that involve inflammatory pathways.

The Effect and Potential Mechanism of Maternal Micronutrient Intake on Offspring Glucose Metabolism: An Emerging Field

Diabetes has become the most common metabolic disease around the world. In addition to genetic and environmental factors in adulthood, the early life environment is critical to the progression of diabetes in adults, especially the environment during the fetal period; this concept is called “fetal programming.” Substantial evidence has illustrated the key role of early life macronutrient in programming metabolic diseases. Recently, the effect of maternal micronutrient intake on offspring glucose metabolism during later life has become an emerging field. This review focuses on updated human and animal evidence about the effect of maternal micronutrient status on offspring glucose metabolism and the underlying mechanism.

Characterization of an Endemic Plant Origanum grosii from Morocco: Trace Element Concentration and Antihyperglycemic Activities

Origanum genus is one of the most widely used herbs in folk medicine for its biological properties. The present investigation aims to characterize, for the first time, endemic Origanum grosii collected from the Taounate region, Morocco. This characterization was realized by determining the concentration of metals in different parts of the plant (flowers, leaves, and stems) by ICP-MS, and the results were studied statistically by Principal Component Analysis (PCA). Phytochemical screening with the dosage of polyphenols and flavonoids has been conducted. To know more about this species, antihyperglycemic tests have been performed to highlight the presence or absence of the antidiabetic effect for this plant. An Oral Glucose Tolerance Test (OGTT) has been performed on normal mice which were divided into two groups of six mice each. Group 1 (control group) was treated with distilled water, and group 2 was treated with an aqueous extract of O. grosii by gavage at 150 mg/kg. Digestive enzyme α-amylase inhibition assay has also been evaluated to study the inhibition effect of the studied extract using acarbose as a control. The results showed that the leaves exhibited a high concentration of trace elements (Ca, Mg, and K) and total absence of heavy metals, which were found in small quantities (Cr, Ni, and B) on the stems, and this makes the plant safe to use. On the other hand, tannins, flavonoids, triterpenes, and steroids were the major families strongly present in this species. The antidiabetic results showed that O. grosii have significantly reduced postprandial hyperglycemia after glucose loading in normal rats. It showed also that this species has a significant antihyperglycemic activity reflected by the inhibition of α-amylase. The one responsible for this property could be the synergy between the trace elements and the nature of the chemical families of O. grosii species, which can make this plant useful in the management of postprandial hyperglycemia.

Biogeographic and Evolutionary Patterns of Trace Element Utilization in Marine Microbial World

Trace elements are required by all organisms, which are key components of many enzymes catalyzing important biological reactions. Many trace element-dependent proteins have been characterized; however, little is known about their occurrence in microbial communities in diverse environments, especially the global marine ecosystem. Moreover, the relationships between trace element utilization and different types of environmental stressors are unclear. In this study, we used metagenomic data from the Global Ocean Sampling expedition project to identify the biogeographic distribution of genes encoding trace element-dependent proteins (for copper, molybdenum, cobalt, nickel, and selenium) in a variety of marine and non-marine aquatic samples. More than 56,000 metalloprotein and selenoprotein genes corresponding to nearly 100 families were predicted, becoming the largest dataset of marine metalloprotein and selenoprotein genes reported to date. In addition, samples with enriched or depleted metalloprotein/selenoprotein genes were identified, suggesting an active or inactive usage of these micronutrients in various sites. Further analysis of interactions among the elements showed significant correlations between some of them, especially those between nickel and selenium/copper. Finally, investigation of the relationships between environmental conditions and metalloprotein/selenoprotein families revealed that many environmental factors might contribute to the evolution of different metalloprotein and/or selenoprotein genes in the marine microbial world. Our data provide new insights into the utilization and biological roles of these trace elements in extant marine microbes, and might also be helpful for the understanding of how these organisms have adapted to their local environments.

Role of Minerals and Trace Elements in Diabetes and Insulin Resistance

Minerals and trace elements are micronutrients that are essential to the human body but present only in traceable amounts. Nonetheless, they exhibit well-defined biochemical functions. Deficiencies in these micronutrients are related to widespread human health problems. This review article is focused on some of these minerals and trace element deficiencies and their consequences in diabetes and insulin resistance. The levels of trace elements vary considerably among different populations, contingent on the composition of the diet. In several Asian countries, large proportions of the population are affected by a number of micronutrient deficiencies. Local differences in selenium, zinc, copper, iron, chromium and iodine in the diet occur in both developed and developing countries, largely due to malnutrition and dependence on indigenous nutrition. These overall deficiencies and, in a few cases, excess of essential trace elements may lead to imbalances in glucose homeostasis and insulin resistance. The most extensive problems affecting one billion people or more worldwide are associated with inadequate supply of a number of minerals and trace elements including iodine, selenium, zinc, calcium, chromium, cobalt, iron, boron and magnesium. This review comprises various randomized controlled trials, cohort and case-controlled studies, and observational and laboratory-based studies with substantial outcomes of micronutrient deficiencies on diabetes and insulin resistance in diverse racial inhabitants from parts of Asia, Africa, and North America. Changes in these micronutrient levels in the serum and urine of subjects may indicate the trajectory toward metabolic changes, oxidative stress and provide disease-relevant information.

Biomonitoring human urinary levels of 26 metal elements in multi-race coexistence region of Xinjiang, China

The human biological monitoring of metals (metalloids) is of importance, which concentrations could indicate a wide range of health related information. Reference values (RVs) of metals (metalloids) in specific matix of populations are critically required when performing a statistical evaluation accurately. Recent studies show that RVs of metals (metalloids) are influenced by many multiple factors, including lifestyle, diet, dissimilar environment, location, as well as race. However, it is virtually absent across many nations/regions, especially multi-race coexistence regions. The aim of the work was to establish RVs of metals (metalloids) in urine of adult in Xinjiang, China. Totally 178 urine samples from healthy volunteers were collected and analyzed by inductively coupled plasma mass spectrometer or optical emission spectrometer (ICP-MS/OES). RVs of 26 metals (metalloids) in urine for adult of Xinjiang, China were then established. Effects of race, gender and age on RVs were investigated using partial least squares discriminant analysis and student T-test. The result demonstrated that above factors showed mild influence for the establishment of RVs. The RVs derived from total 178 urine adult samples (Han and Uygur half of each) can be applied for different race, gender and age periods. Moreover, it was observed that three metals (metalloids), As, Sc and Ba significantly varied between some subgroups. The established RVs will be valuable for future health or environmental evaluation, and can serve as a theoretical reference for RVs establishment in multi-race coexistence region.

Serum levels of trace minerals and heavy metals in severe COPD patients with and without pulmonary hypertension

Aim

The aim of the current study was to assess the serum levels of trace minerals/heavy metals in COPD patients with and without pulmonary hypertension (PH) and to investigate their correlations to demographic, clinical, and biochemical variables.

Materials and methods

This cross-sectional study was performed in Van Yuzuncu Yil University Medical Faculty between April 2013 and July 2013. Cases were allocated into three groups: Group 1 consisted of severe COPD patients; Group 2 was made up of COPD patients with PH; and healthy controls constituted Group 3. Demographic, radiological, and biochemical variables, as well as the serum levels of trace minerals and heavy metals, were noted and compared in these three groups.

Results

COPD patients were older and had higher rates of smoking habit, diabetes mellitus, and hypertension compared to the control group. Carotid intima-media thickness was increased bilaterally, and serum levels of Co, Cu, and Fe were higher in COPD patients. Left carotid intima-media thickness was increased, and serum levels of Cd, Co, and Fe were found to be higher in COPD cases with PH compared to COPD patients without PH.

Conclusion

Our results show that serum levels of trace minerals and heavy metals may be altered in COPD and PH.

Hierarchical structure of biological systems: a bioengineering approach

A general theory of biological systems, based on few fundamental propositions, allows a generalization of both Wierner and Berthalanffy approaches to theoretical biology. Here, a biological system is defined as a set of self-organized, differentiated elements that interact pair-wise through various networks and media, isolated from other sets by boundaries. Their relation to other systems can be described as a closed loop in a steady-state, which leads to a hierarchical structure and functioning of the biological system. Our thermodynamical approach of hierarchical character can be applied to biological systems of varying sizes through some general principles, based on the exchange of energy information and/or mass from and within the systems.

Lipid peroxidation and changes of trace elements in mice treated with paradichlorobenzene

Paradichlorobenzene (pDCB) has been used as a space deodorant and moth repellant, as well as an intermediate in the chemical industry. Given its broad applications and high volatility, considerable concern exists regarding the adverse health effects of pDCB in the home and the workplace. In this study, changes in lipid peroxidation, antioxidants, and trace element levels in the liver and kidney of pDCB-treated mice were investigated to determine their roles in toxicity. Mice were orally gavaged once daily for seven consecutive days with pDCB (0 (corn oil control), 450, and 900 mg/kg). The level of malondialdehyde (MDA), an end product of lipid peroxidation, markedly increased in the high-dose pDCB group in both the liver and kidney compared with the control group. Changes in hepatic levels of reduced glutathione (GSH) in the pDCB groups were indistinguishable from the control group, while renal levels of reduced GSH in the high-dose pDCB group were significantly lowered in comparison to the control and the low-dose groups. Superoxide dismutase (SOD) activity in the liver of mice treated with pDCB showed a downward trend, whereas there was no consistent trend associated with changes in SOD activity in the kidney. Additionally, renal iron levels in the high-dose pDCB group were significantly decreased compared with the low-dose group and the controls, whereas hepatic iron content in the low-dose pDCB group was significantly lower compared with the controls. Selenium and zinc levels in the kidney were both significantly decreased in the high-dose pDCB group vs. the control and low-dose groups. There were no treatment-induced changes in copper levels in either the kidney or liver. However, a significant increase was found in the liver zinc/copper ratio in the high-dose pDCB group vs. the controls. In addition, blood zinc levels showed a downward trend with increased pDCB dosage. These results suggest that pDCB toxicity is mediated by oxidative damage and tissue-specific alterations in trace element levels both in the liver and the kidney of mice.

A network biology model of micronutrient related health

Micronutrients are involved in specific biochemical pathways and have dedicated functions in the body, but they are also interconnected in complex metabolic networks, such as oxidative-reductive and inflammatory pathways and hormonal regulation, in which the overarching function is to optimise health. Post-genomic technologies, in particular metabolomics and proteomics, both of which are appropriate for plasma samples, provide a new opportunity to study the metabolic effects of micronutrients in relation to optimal health. The study of micronutrient-related health status requires a combination of data on markers of dietary exposure, markers of target function and biological response, health status metabolites, and disease parameters. When these nutrient-centred and physiology/health-centred parameters are combined and studied using a systems biology approach with bioinformatics and multivariate statistical tools, it should be possible to generate a micronutrient phenotype database. From this we can explore external factors that define the phenotype, such as lifestage and lifestyle, and the impact of genotype, and the results can also be used to define micronutrient requirements and provide dietary advice. New mechanistic insights have already been developed using biological network models, for example genes and protein-protein interactions in the aetiology of type 2 diabetes mellitus. It is hoped that the challenge of applying this approach to micronutrients will, in time, result in a change from micronutrient oriented to a health oriented views and provide a more holistic understanding of the role played by multiple micronutrients in the maintenance of homeostasis and prevention of chronic disease, for example through their involvement in oxidation and inflammation.

Metabonomic and metallomic profiling in the amniotic fluid of malnourished pregnant rats

Epidemiology and studies in animal models have revealed that prenatal malnutrition is highly correlated with abnormal fetal neurodevelopment. We present here a combined metabonomic and metallomic profiling technique to associate the metabolic and trace-elemental composition variations of rat amniotic fluid (AF) in malnourished pregnant rats with the retardation of fetal rat neurodevelopment. The AF samples from three groups of pregnant Sprague-Dawley rats, which were fed either a normal diet, a low-protein diet, or "a famine diet", were subjected to GC/MS and ICP/MS combined with multivariate data analysis (MVDA). PCA scores plot of both GC/MS and ICP/MS data showed similar and unique metabolic signatures of AF in response to the different diets. Rats in the famine group released increased amounts of glycine, inositol, putrescine, and rubidium and decreased amounts of methionine, dopa, tryptophan, glutamine, zinc, cobalt, and selenium in the AF. These discriminable variations in the AF may indicate the abnormality of a number of metabolic pathways in fetal rats including the folate cycle and methionine pathway, the monoamine pathway, and tri-iodothyronine (T3) metabolism. The abnormalities may be the result of metabolites or elemental differences or a combination of both. This study demonstrates the potential of combining profiling of small-molecule metabolites and trace elements to broaden the understanding of biological variations associated with fetal neurodevelopment induced by environmental perturbation.

Evaluation of methods for trace-element determination with emphasis on their usability in the clinical routine laboratory

Commonly used techniques for trace-element analysis in human biological material are flame atomic absorption spectrometry (FAAS), graphite furnace atomic absorption spectrometry (GFAAS), inductively coupled plasma atomic emission spectrometry (ICP-AES) and inductively coupled plasma mass spectrometry (ICP-MS). Elements that form volatile hydrides, first of all mercury, are analysed by hydride generation techniques. In the absorption techniques the samples are vaporized into free, neutral atoms and illuminated by a light source that emits the atomic spectrum of the element under analysis. The absorbance gives a quantitative measure of the concentration of the element. ICP-AES and ICP-MS are multi-element techniques. In ICP-AES the atoms of the sample are excited by, for example, argon plasma at very high temperatures. The emitted light is directed to a detector, and the optical signals are processed to values for the concentrations of the elements. In ICP-MS a mass spectrometer separates and detects ions produced by the ICP, according to their mass-to-charge ratio. Dilution of biological fluids is commonly needed to reduce the effect of the matrix. Digestion using acids and microwave energy in closed vessels at elevated pressure is often used. Matrix and spectral interferences may cause problems. Precautions should be taken against trace-element contamination during collection, storage and processing of samples. For clinical problems requiring the analysis of only one or a few elements, the use of FAAS may be sufficient, unless the higher sensitivity of GFAAS is required. For screening of multiple elements, however, the ICP techniques are preferable.