Alteration of local adipose tissue trace element homeostasis as a possible mechanism of obesity-related insulin resistance

Plasma levels and dietary intake of minerals in patients with type 2 diabetes and chronic kidney disease: A case-control study

BACKGROUND AND AIM

Diabetic kidney disease (DKD) is the primary cause of chronic kidney disease (CKD) worldwide. Altered mineral levels leading to adverse outcomes are widely reported in diabetes but limited in DKD, in the Indian scenario, hence this study was taken up to address this issue.

METHODS

A hospital-based case-control study was taken up with 54 healthy controls (C) and 140 subjects with type 2 diabetes wherein 74 subjects with diabetes and CKD formed the DKD group, and 66 subjects with diabetes but no CKD formed the diabetic no-chronic kidney disease (DNCKD) group. High-resolution inductively coupled plasma mass spectrometry was used to evaluate the blood levels of minerals (calcium (Ca), vanadium (V), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), copper (Cu), zinc (Zn), and selenium (Se)), and a raw food-based food frequency questionnaire for dietary intakes. Estimated glomerular filtration rate (eGFR) was calculated using the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation (mL/min/1.73 m2) and albuminuria. Spearman's rank correlation was used to evaluate the relationship between the categorical variables.

RESULTS

The median values of plasma Ca in the DKD group were significantly lower compared with the DNCKD and C groups (10.5 mg/dL vs. 11.0 mg/dL and 11.7 mg/dL, p<0.001). Furthermore, plasma Ca levels lowered with declining kidney function, as evidenced by the eGFR and albuminuria segregation. Dietary intake of minerals did not correlate with the corresponding plasma levels. However, in the DKD group, eGFR correlated positively with the plasma levels of Ca (r= 0.422, p=0.001), Cr (r= 0.351, p=0.008), Mn (r= 0.338, p=0.011), Fe (r= 0.403, p=0.002), Cu (r= 0.274, p=0.041) and negatively with Se (r= -0.486, p<0.001).

CONCLUSION

Plasma Ca levels are lower in the DKD group with a strong positive association with eGFR, indicating its role in predicting the onset and progression of kidney function decline.

Interactive Effects of Obesity and Hypertension on Patterns of Hair Essential Trace Element and Mineral Content in Adult Women

The objective of the present study was to evaluate potential similar patterns and interactive effects of obesity and hypertension on hair essential trace element and mineral content in adult women. In this cross-sectional study, a total of 607 adult women divided into controls (n = 101), groups with obesity without hypertension (n = 199), hypertension without obesity (n = 143), and both obesity and hypertension (n = 164) were included in the study. Assessment of hair mineral and trace element levels was performed by inductively-coupled plasma mass-spectrometry. Hair Ca, Mg, Co, and Mn levels in women with obesity, hypertension, and both diseases were significantly lower, compared to controls. Hair Mg levels in women with obesity and hypertension were significantly lower, whereas hair Na and K were found to be higher when compared to other groups. Hair Fe and V content in obese patients was lower than in other groups. Obesity was associated with lower hair Cu levels, whereas patients with hypertension had higher hair Cu content. Hypertension was also associated with higher hair Cr and Se content irrespective of body weight. Hair Zn levels in obese women with and without hypertension were significantly lower than those in healthy controls and normal-weight women with hypertension. In multiple regression models hair Mg was considered as a significant negative predictor of both systolic and diastolic blood pressure values. The observed alterations in hair trace element and mineral content provide an additional link between obesity and hypertension, although further detailed studies are required.

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.

Metal Homeostasis and Exposure in Distinct Phenotypic Subtypes of Insulin Resistance among Children with Obesity

BACKGROUND

Trace elements and heavy metals have proven pivotal roles in childhood obesity and insulin resistance. However, growing evidence suggests that insulin resistance could encompass distinct phenotypic subtypes.

METHODS

Herein, we performed a comprehensive metallomics characterization of plasma samples from children and adolescents with obesity and concomitant insulin resistance, who were stratified as early (N = 17, 11.4 ± 2.4 years), middle (N = 16, 11.8 ± 1.9 years), and late (N = 33, 11.7 ± 2.0 years) responders according to the insulin secretion profile in response to an oral glucose tolerance test. To this end, we employed a high-throughput method aimed at determining the biodistribution of various essential and toxic elements by analyzing total metal contents, metal-containing proteins, and labile metal species.

RESULTS

Compared with the early responders, participants with delayed glucose-induced hyperinsulinemia showed a worsened insulin resistance (HOMA-IR, 4.5 vs. 3.8) and lipid profile (total cholesterol, 160 vs. 144 mg/dL; LDL-cholesterol, 99 vs. 82 mg/dL), which in turn was accompanied by sharpened disturbances in the levels of plasmatic proteins containing chromium (4.8 vs. 5.1 µg/L), cobalt (0.79 vs. 1.2 µg/L), lead (0.021 vs. 0.025 µg/L), and arsenic (0.077 vs. 0.17 µg/L). A correlation analysis demonstrated a close inter-relationship among these multielemental perturbations and the characteristic metabolic complications occurring in childhood obesity, namely impaired insulin-mediated metabolism of carbohydrates and lipids.

CONCLUSIONS

These findings highlight the crucial involvement that altered metal homeostasis and exposure may have in regulating insulin signaling, glucose metabolism, and dyslipidemia in childhood obesity.

Demographic and anthropometric characteristics and their effect on the concentration of heavy metals (arsenic, lead, chromium, zinc) in children and adolescents

Background

Biomonitoring is a well-established method for assessing people's exposure to contaminants in the environment. Many non-communicable diseases can be prevented or aggravated by physiologically monitoring heavy metals in biological matrices such as urine, evaluating their association with non-communicable diseases, and attempting to limit exposure to them. The focus of this research was to determine the association between potentially toxic elements (PTE) such as arsenic (As), lead (Pb), chromium (Cr), and zinc (Zn) urine concentrations and anthropometric indices and demographic data in children and adolescents aged 6-18 years in Kerman, Iran.

Methods

106 children and adolescents aged 6-18 years in Kerman were randomly selected. A questionnaire was used to acquire demographic information from the participants' parents. Height, weight, and waist circumference (WC) were all assessed, as well as body mass index (BMI) and BMI Z-score. Induced Coupled Plasma Mass Spectrometry (ICP/MS) was used to quantify As, Pb, Cr, and Zn concentrations in participants' urine.

Results

The geometric mean concentrations were As (38.72 ± 39.30), Pb (19.58 ± 22.91), Cr (1.06 ± 0.28), and Zn (344.72 ± 288.16) μg/creatinine. Boys aged 12-18 years old had higher mean concentration of As than boys aged 6-11 years old (p = 0.019) according to two measurement standards, μg/L, and μg/creatinine, whereas girls had no significant difference. In general, there was a strong association between parental education and metal concentrations of As, Pb, and Cr. As, Pb, and Zn (μg/creatinine) had a significant positive association with BMI z-score and BMI. As, Pb, and Zn metals were shown to have a substantial positive association (p < 0.001). There was no evidence of an association between the metals evaluated and WC.

Conclusions

The findings of this study generally showed that there was a significant association between demographic characteristics and exposure to these metals in children and adolescents, indicating that these people were exposed to these metals, which can harm their health. As a result, the pathways of exposure to metals must be limited.

Freshwater Macroalgae, Oedogonium, Grown in Wastewater Reduce Diet-Induced Metabolic Syndrome in Rats

Macroalgae produce compounds with industrial, pharmaceutical and nutritional applications. In this study, biomass from the freshwater macroalgal genus Oedogonium was grown in either treated municipal wastewater (M) or ash dam water from a coal-fired power station (D). The biomass was investigated for its metabolic responses in high-carbohydrate, high-fat diet-fed rats, a model of human metabolic syndrome. The Oedogonium biomass cultured in M contained higher amounts of K, Mg, omega-3 polyunsaturated fatty acids (PUFA), insoluble fibre and β-carotene, while biomass grown in D contained higher amounts of Al, Fe, V, Zn, Mn and As. Biomass from M further increased body weight and inflammation in the heart and colon in high-carbohydrate, high-fat diet-fed rats. In contrast, biomass from D prevented changes in metabolic, cardiovascular and liver parameters without changing tissue histology. We suggest that increased intake of metals and metalloids through macroalgal biomass from D may decrease abdominal fat deposition while polysaccharides, PUFA and carotenoids from M may improve blood glucose responses in an obesogenic diet. Thus, macroalgal biomass grown in different wastewater sources could be acceptable for feed or food applications. This biomass could even provide potential health benefits in diet-induced metabolic syndrome.

Influence of Sex and Strain on Hepatic and Adipose Tissue Trace Element Concentrations and Gene Expression in C57BL/6J and DBA/2J High Fat Diet Models

The objective of this study was to determine the influence of sex and strain on the dysregulation of trace element concentration and associative gene expression due to diet induced obesity in adipose tissue and the liver. Male and female C57BL/6J (B6J) and DBA/2J (D2J) were randomly assigned to a normal-fat diet (NFD) containing 10% kcal fat/g or a mineral-matched high-fat diet (HFD) containing 60% kcal fat/g for 16 weeks. Liver and adipose tissue were assessed for copper, iron, manganese, and zinc concentrations and related changes in gene expression. Notable findings include three-way interactions of diet, sex, and strain amongst adipose tissue iron concentrations (p = 0.005), adipose hepcidin expression (p = 0.007), and hepatic iron regulatory protein (IRP) expression (p = 0.012). Cd11c to Cd163 ratio was increased in adipose tissue due to HFD amongst all biological groups except B6J females, for which tissue iron concentrations were reduced due to HFD (p = 0.002). Liver divalent metal transporter 1 (DMT-1) expression was increased due to HFD amongst B6J males (p < 0.005) and females (p < 0.004), which coincides with the reduction in hepatic iron concentrations found in these biological groups (p < 0.001). Sex, strain, and diet affected trace element concentration, the expression of genes that regulate trace element homeostasis, and the expression of macrophages that contribute to tissue iron-handling in adipose tissue. These findings suggest that sex and strain may be key factors that influence the adaptive capacity of iron mismanagement in adipose tissue and its subsequent consequences, such as insulin resistance.

Quercetin Beneficial Role in the Homeostatic Variation of Certain Trace Elements in Dyslipidemic Mice

Background

Quercetin's role in the homeostasis of certain trace elements in dyslipidemia induced in mice was assessed.

Methods

Forty BALB/c mice were allocated into 4 groups as follows: control; HFD, received fat diet; HFD + Q group, received HFD +500 mg/L quercetin; and blank control (Q)—normal food + 500 mg/L quercetin in drinking water.

Results

By analyzing the values of total proteins, albumins, cholesterol, triglycerides, HDL cholesterol, LDL cholesterol, and the levels of several trace elements in blood and organs, we perceived a statistically significant increase (^∗∗, p < 0.01) of TP, ALB, TC, TGE, and LDL-c. A nonsignificant decrease was ascertained to HDL-c value in the HFD and quercetin groups (p > 0.05). In the HFD group, all analyzed elements in the kidney and spleen increased, also Cu, Li, Mg, Mn, Pb, and of B, Ba, Cr, Cd, Cu, Fe, Li, Mn, Ni, Pb, and Zn in the heart increased, but furthermore, Ag, B, Ba, Cd, Cr, Fe, Ni, and Zn in blood, Ag and Zn in the liver, and Cd in the spleen decreased. In the HFD group who received quercetin, elements (except B) were decreased in kidney and liver, also increased Ag, Ba, Cr, Fe, Li, Ni, Zn in blood, but similarly, Ag, B, Ba, Cd, Cu, Mn, and Pb declined in the spleen and heart.

Conclusions

Results proved the quercetin beneficial role.

Cadmium acute exposure induces metabolic and transcriptomic perturbations in human mature adipocytes

Obesity is considered as a major public health concern with strong economic and social burdens. Exposure to pollutants such as heavy metals can contribute to the development of obesity and its associated metabolic disorders, including type 2 diabetes and cardiovascular diseases. Adipose tissue is an endocrine and paracrine organ that plays a key role in the development of these diseases and is one of the main target of heavy metal accumulation. In this study, we determined by inductively coupled plasma mass spectrometry cadmium concentrations in human subcutaneous and visceral adipose tissues, ranging between 2.5nM and 2.5µM. We found a positive correlation between cadmium levels and age, sex and smoking status and a negative correlation between Cd and body mass index. Based on cadmium adipose tissue concentrations found in humans, we investigated the effects of cadmium exposure, at concentrations between 1nM and 10µM, on adipose-derived human mesenchymal stem cells differentiated into mature adipocytes in vitro. Transcriptomic analysis highlighted that such exposure altered the expression of genes involved in trace element homeostasis and heavy metal detoxification, such as Solute Carrier Family transporters and metallothioneins. This effect correlated with zinc level alteration in cells and cellular media. Interestingly, dysregulation of zinc homeostasis and transporters has been particularly associated with the development of obesity and type 2 diabetes. Moreover, we found that cadmium exposure induces the pro-inflammatory state of the adipocytes by enhancing the expression of genes such as IL-6, IL-1B and CCL2, cytokines also induced in obesity. Finally, cadmium modulates various adipocyte functions such as the insulin response signaling pathway and lipid homeostasis. Collectively, our data identified some of the cellular mechanisms by which cadmium alters adipocyte functions, thus highlighting new facets of its potential contribution to the progression of metabolic disorders.

The Influence of Organic Vanadium Complexes on an Antioxidant Profile in Adipose Tissue in Wistar Rats

One of the aspects of biological activity of vanadium is its influence on carbohydrate metabolism. For more than 30 years, various vanadium complexes have been tested as antidiabetic agents. This study researched organic vanadium complexes with bipyridinium ligands and their influences on metabolic rate, as well as on the antioxidant activity of adipose tissue. The effects of sodium (2,2′-bipyridine) oxidobisperoxovanadate (V) octahydrate (known as the V complex), bis(2,2′-bipyridine) oxidovanadium (IV) sulfate dehydrate (known as the B complex), and bis(4.4′-dimethyl-2,2′-bipyridine) oxidovanadium (IV) sulfate dihydrate (labelled as the BM complex) were assessed. Solutions of the tested complexes were introduced intraperitoneally with a probe to animals fed with either a control diet or a high-fat diet. The BM complex had a significant influence on the increase in ferric reducing antioxidant power, as well as on the concentration of glutathione in the adipose tissue of rats fed with a high-fat diet. The V complex increased the concentration of glutathione in the adipose tissue of rats fed with control fodder, as well as significantly reduced the relative change in rat weight for the high-fat diet. Furthermore, the presence of each tested vanadium complex had an impact of statistically significant increase in basal metabolic rate, regardless of applied diet. Further research on these organic vanadium complexes is necessary to understand the mechanisms responsible for their ability to affect adipose tissue.

Relationship between gestational diabetes and serum trace element levels in pregnant women from Eastern Iran: a multivariate approach

The prevalence of gestational diabetes mellitus (GDM) has increased over the recent decades. Exposure to environmental contaminants may be a risk factor for the development of GDM, but this is heavily dependent on particular circumstances. Studies on various areas linking various factors are therefore needed. We examined the associations between serum trace element levels and incidents of GDM among 102 pregnant women (diabetic n = 60 and healthy n = 42) living in Birjand (Iran). Blood serum samples were analyzed for concentrations of elements linked to particulate matter air pollution such as As, Cd, Cu, Hg, Mn, Ni, V, and Zn. Concentrations of As (8.58 vs. 3.15 μg/L), Cd (6.74 vs. 0.52 μg/L), and Hg (2.60 vs. 0.90 μg/L) were significantly higher in women with GDM. Risk difference (RD) estimation showed that As, 0.516 (0.355, 0.677); Cd, 0.719 (0.534, 0.904); and Hg, 0.505 (0.276, 0.735) increase GDM probability, while V lower that risk, -0.139 (-0.237, -0.042). With the principal component analysis, we were able to separate subjects according to their GDM status based on element levels. Such classification revealed very high efficiency with a true positive rate of 93%, according to linear discriminant analysis. GDM subjects presented higher levels of As, Cd, and Hg, indicating that these elements may disturb insulin metabolism and promote the development of GDM. Therefore, we conclude that systematic monitoring of trace elements followed by multivariate modeling in women planning pregnancy should be carried out to prevent the development of GDM.

Adipose tissue cadmium concentrations as a potential risk factor for insulin resistance and future type 2 diabetes mellitus in GraMo adult cohort

Adipose tissue has been recently highlighted as a promising matrix for evaluation of cadmium's (Cd) long-term exposure although not frequently considered in epidemiological studies. The association between Cd exposure and type 2 Diabetes Mellitus (T2DM) remains unclear. This work aimed to explore the association between adipose tissue Cd levels and T2DM incidence over a 16-year follow-up in an adult cohort from Southern Spain considering smoking status. We also performed complementary cross-sectional analyses focused on subclinical markers of glucose homeostasis at recruitment. Clinical information was obtained from hospital databases. Socio-demographic characteristics, lifestyle and diet were collected by face-to-face interviews. Homeostatic model assessment (HOMA) values of insulin sensitivity/resistance and β-cell function were calculated using fasting serum glucose, insulin, and C-peptide levels at recruitment. Adipose tissue Cd concentrations were quantified by inductively coupled plasma mass spectrometry. Statistical analyses were performed by means of Cox-regression and multivariable linear regression models. Participants in the 4th quartile (Q4) of Cd concentrations showed a non statistically-significant increased T2DM risk (Hazard Ratio (HR) Q4 vs Q1: 1.97; 95% Confidence Interval (CI): 0.69, 5.66). This association was particularly strong and suggestive in current smokers (HR: 2.19; 95% CI: 0.98, 4.98). Interestingly, smokers in the 2nd tertile (T2) of adipose tissue Cd levels showed increased log-transformed insulin resistance (beta T2 vs T1: 0.52; 95% CI: 0.07, 0.97), as well as higher log-transformed insulin levels (beta T2 vs T1: 0.52; 95% CI: 0.08, 0.95). We found evidences supporting that Cd exposure, particularly from tobacco smoking, could be a risk factor for T2DM. In addition, our results support the potential relevance of adipose tissue as a matrix for Cd exposure assessment.

Associations of residential and occupational history with the distribution of persistent pollutant mixtures in adipose tissue samples

This research aims to explore clusters of a mixture of 15 Persistent Toxic Substances (PTSs) in the adipose tissue of 227 individuals of an adult cohort from Granada Province (Southern Spain). Information about residence and occupation during participants lifetime was gathered by means of validated questionnaires. Clusters of pollutants in the study population were identified by Principal Component Analyses (PCA). PCA analyses revealed three major clusters of pollutants: PC1, representing predominantly an assortment of metal(loid)s, namely aluminium, arsenic, chromium, nickel and lead; PC2, including mostly Organochlorine Pesticides (OCPs), such as HCB, β-HCH and p,p'-DDE; and PC3, gathering mainly a mixture of Polychlorinated Biphenyls (PCB-138, PCB-153 and PCB-180) and metals (cadmium, cobalt and chromium). The patterns of distribution of individual pollutants and their mixtures were explored through Geographic Information Systems and multivariable linear regression models. Living in rural areas was associated with decreased levels of the mixture of PCBs and metals. Residents of industrial and heavy traffic areas showed increased levels of the mixture of metal(loid)s. Those living in rural and semi-rural areas at recruitment had decreased levels of the OCP mixture. Occupational history related to agriculture and food industry was associated with increased levels of the mixture of metal(loid)s, whereas those who had been involved in motor and industrial activities showed increased levels of the OCP mixture. Participants who had worked in cleaning and housekeeping activities for long periods showed decreased levels of the mixture of PCBs and metals. Our research revealed suggestive clusters of exposure, that emphasized the need for further epidemiological studies to address the effect of environmental pollutants from a mixture perspective. Results also highlight the potential of adipose tissue as a matrix for exposure assessment to combinations of different families of contaminants.

Content of essential and toxic trace elements in organs of obese Wistar and Zucker leprfa rats receiving quercetin

BACKGROUND

The levels of a number of essential and toxic trace elements in organs and tissues are affected by the disruptions in body homeostasis caused by obesity. Some of these elements may also be influenced by the consumption of biologically active substances of polyphenolic origin, which possess potent abilities to complex with transition metal ions.

AIMS

The aim of this study was to determine the content of essential and toxic trace elements in Wistar outbred and hereditary obese Zucker Lepr^fa (Z) rats consuming a standard balanced diet or hypercaloric diet with excess fat and fructose, supplemented with quercetin or not supplemented.

MATERIALS AND METHODS

Male Wistar and Z rats were fed a control AIN-93M-based semi-synthetic diet or a high-fat-high-carbohydrate diet (HFCD, with 30% fat by weight and 20% fructose provided in the drinking water). A portion of the animals in each line and diet group was administered quercetin at 50 mg/kg body weight. Essential trace elements were included in the diets as a high-purity salt mixture. After the termination of feeding on day 63, the livers, kidneys, and brains of the rats were excised and the content of 16 elements (Fe, Mg, Cu, Mn, Co, Se, Zn, Cr, Ni, Al, Cd, As, Pb, V, Cs, and Ag) was measured by inductively coupled plasma mass spectrometry (ICP-MS).

RESULTS

In the livers of the Z rats, the contents of Co, Zn, Mg, Fe, Se, and V were reduced and the content of Cr was increased compared to that of the Wistar rats. Supplementation with quercetin significantly decreased liver Fe, V, and Se content, which was more noticeable in the Wistar rats than in the Z rats. In kidneys of Z rats consuming control diet, the contents of Co, Cu, and Cs were decreased whereas those of Ni, Al, and Se were increased compared with the contents in the Wistar rats. The same trend was observed with HFCD feeding except for Cs content. Quercetin reduced kidney V content in both rat lines fed both diets, whereas it reduced Se and Cs only in the Z rats fed control diet. In the brains of the Z rats, a large increase was observed in some trace elements including Pb, Cd, Al, Cr, Ni, Fe, and V compared with the levels in the Wistar rat brains. Supplementation of the control diet with quercetin decreased Al and Ni in the brains of the Z rats.

CONCLUSION

There were significant differences in the mineral content of organs between the Wistar and Z rats, with different propensities for obesity. Moreover some of these effects had no straightforward association with decreased feed consumption or hepatic fat accumulation. When introduced into the diets, quercetin affected the content of essential and toxic elements, but with ambiguous physiological significance. Thus, indicators of essential and toxic trace elements deserve to be used in the protocols of preclinical as well as clinical trials of biologically active substances and food supplements.

Zinc Supplementation Might Not Affect Serum Leptin and Adiponectin Levels in Adults: A Systematic Review and Meta-Analysis of Randomized Controlled Clinical Trials

Background:

Zinc as one of the important trace elements in human health has been suggested to be a supplement for modifying the level of adipokines, whereas findings from studies have been inconsistent. This study aimed to systematically review the evidence provided by randomized controlled trials (RCTs) regarding the effect of zinc supplementation on serum adipokines levels.

Methods:

PubMed, Google Scholar, Web of Science, and Scopus were systematically searched up to June 2019. The mean differences and their corresponding standard deviations (SDs) of changes in serum adipokines levels were used as effect size.

Results:

Eight eligible RCTs (leptin n=6, adiponectin n=3) were included in the current study. There were no significant changes in serum leptin levels [weighted mean difference (WMD) =0.60 ng/ml, 95% confidence interval (CI): −1.78, 2.99; I-squared (I²) = 64.3%] and adiponectin levels (WMD = 1.09 ng/ml, 95% CI: −0.76, 3.18, I² = 78.8%) following zinc supplementation compared to placebo group. These findings did not change after considering several subgroups including gender, study duration, health status, body weight and the type of zinc used for supplementation.

Conclusion:

No evidence was found to support the efficacy of dietary zinc supplements on serum levels of adipokines. Further, high-quality, long-term controlled clinical trials are warranted to confirm these findings.

Selenium, Zinc, Chromium, and Vanadium Levels in Serum, Hair, and Urine Samples of Obese Adults Assessed by Inductively Coupled Plasma Mass Spectrometry

The objective of this study was to investigate of selenium (Se), zinc (Zn), chromium (Cr), and vanadium (V) levels in blood serum, hair, and urine of adult obese patients. A total of 199 lean and 196 obese subjects were enrolled in the study. Serum, hair, and urinary metal and metalloid analysis were performed by inductively coupled plasma mass spectrometry at NexION 300D (PerkinElmer Inc., USA). The results established that obese subjects were characterized by 47% and 30% lower serum Cr and V levels compared with controls, respectively, whereas serum Se levels exceeded control values by 9%. In contrast, hair Cr, Se, and V content in obese subjects exceeded the control values by 51%, 21%, and 50%, respectively. In turn, hair Zn levels were found to be significantly lower by 11% compared with the lean control values. In urine, the levels of V and Zn were found to be 30% and 18% higher in obese patients. Prevalence of hypertension in obese subjects was associated with a trend for impaired Se and Zn levels. In a regression model adjusted for age, gender, hypertension, atherosclerosis, and glucose intolerance, serum Cr, V, and hair Zn were inversely associated with body mass index (BMI), whereas hair Se was considered as the positive predictor. Our data allow proposing that the observed alterations may at least partially contribute to metabolic disturbances in obesity. In turn, monitoring of Se exposure in a well-nourished adult population is required to reduce its potential contribution to obesity.

Association between Trace Elements and Body Composition Parameters in Endurance Runners

The aim of this study was to determine the possible correlations between essential and toxic trace elements of plasma with several anthropometric and body composition parameters and performance in endurance runners. Sixty-five high-level middle and long-distance runners (21  ±  3 years; 1.77 ± 0.05 m; 64.97 ± 7.36 kg; VO₂ max. 67.55 ± 4.11 mL/min/kg) participated in the present study. Abdominal, subscapular, iliac crest, triceps, front thigh and medial calf skinfold thicknesses and an incremental test until exhaustion were recorded. Body, fat, muscle and bone mass were estimated. Plasma trace elements were analyzed with inductively coupled plasma mass spectrometry (ICP-MS). Correlations and simple linear regression were used to assess the relationship between trace elements and several variables. Different skinfolds, fat mass, muscle mass and bone mass correlated positively and negatively with trace elements such as copper, manganese, selenium, vanadium, zinc, lithium, rubidium, strontium, arsenic, beryllium and lead. Lithium was related with performance. In conclusion, endurance training causes changes in the body concentrations of several trace elements that trigger modifications in body composition that may be interesting, if confirmed in the future, for the control of metabolic diseases such as obesity.

A Search for Similar Patterns in Hair Trace Element and Mineral Content in Children with Down's Syndrome, Obesity, and Growth Delay

The objective of the present study was to perform comparative analysis of hair trace element and mineral levels in children with Down's syndrome, growth delay, and obesity in order to reveal common and specific patterns. Hair Zn (14, 7, and 15%), Ca (38%, 24%, and 47%), and Mg (33%, 31%, and 49%) levels in children with Down's syndrome, obesity, and growth delay were lower than the respective control values. At the same time, patients with Down's syndrome and growth delay were characterized by 27% and 21%, as well as 24% and 20% lower hair Co as well as Cu content than healthy examinees. Certain alterations were found to be disease-specific. Particularly, in Down's syndrome children, hair Cr, Fe, and V levels were significantly lower, whereas hair P content exceeded the control values. Obese children were characterized by significantly increased hair Cr content. At the same time, hair Mn and Si levels in children with growth delay were lower as compared with the controls. In regression models, all three studied diseases were considered as negative predictors of hair Cu content. Down's syndrome and growth delay, but not obesity, were inversely associated with hair Co content. Both Down's syndrome and obesity were inversely associated with hair Zn content. Based on the revealed similarities in altered hair element, content it is proposed that deficiency of essential elements may predispose Down's syndrome patients to certain syndrome comorbidities including growth delay and obesity, although further detailed studies are required.

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.

Adipose tissue concentrations of arsenic, nickel, lead, tin, and titanium in adults from GraMo cohort in Southern Spain: An exploratory study

BACKGROUND

Adipose tissue has been acknowledged as a potential target for obesogenic pollutants, including toxic metal(loid)s. However, the presence of these chemicals in the adipose tissue has been poorly characterized.

OBJECTIVE

To examine the distributions of adipose tissue concentrations of five toxic metal(loid)s (i.e., arsenic [As], nickel [Ni], lead [Pb], tin [Sn], and titanium [Ti]) in adults, and potential socio-demographic and lifestyle factors associated with metal(loid) concentrations.

METHODS

The study population consisted of a subsample of 228 subjects from GraMo cohort in Southern Spain (N = 387). Adipose tissue samples were intra-operatively collected from adults recruited in 2003-2004 in two public hospitals, and concentrations of metal(loid)s in adipose tissue were analyzed in 2015 by High-Resolution Inductively Coupled Plasma Mass Spectrometry. Data on socio-demographic and lifestyle factors were obtained by baseline questionnaire completion. Linear and multinomial regression was used to identify factors associated with metal(loid) levels.

RESULTS

Ni, Pb, Sn, and Ti were detected in all adipose tissue samples, and As in 51% of them. Ni was the metal showing the highest median concentration (0.56 μg/g), followed by Ti (0.31 μg/g), Pb (0.08 μg/g), Sn (0.06 μg/g), and As (0.003 μg/g). Predictors of As levels included area of residence, social class, and oily fish intake; for Ni: area of residence and consumption of cheese, meat, eggs, and canned food; for Pb: vegetables intake and industrial occupation; for Sn: age, body mass index, and consumption of lean fish, eggs, and milk; and cheese intake for Ti. Some of these predictors were sex-specific, particularly those regarding dietary intake.

CONCLUSIONS

This exploratory study provides the first evidence of the occurrence of Ni, Pb, Sn, Ti, and As in adipose tissue from adult population, and highlights the potential of this tissue as a biological matrix for studying exposure levels and chronic health effects of toxic metal(loid)s.

Levels and determinants of adipose tissue cadmium concentrations in an adult cohort from Southern Spain

This study was conceived as a first step to evaluate the suitability of adipose tissue cadmium (Cd) concentrations as a biomarker for the assessment of long-term exposure. Specifically, the aim of this work was to explore the socio-demographic, dietary, and lifestyle determinants of adipose tissue Cd concentrations. The study population is a subsample of GraMo cohort. Adipose tissue samples were intraoperatively collected from 226 adult volunteers recruited in two public hospitals from Granada, Spain. Cd concentrations in adipose tissue were analyzed by High-Resolution Inductively Coupled Plasma Mass Spectrometry (HR-ICP-MS). Data on socio-demographic characteristics, lifestyle, diet and health status were collected by face-to-face interviews. Predictors of Cd concentrations were assessed by multivariable linear regression with a stepwise variable selection. We found detectable levels of Cd in the adipose tissue of all the study participants, with a mean concentration (±standard deviation) of 12.66 ± 18.91 μg/kg. Smoking habit at recruitment was associated with increased adipose tissue Cd concentrations (β for smokers = 0.669 p < 0.001; β for former smokers = 0.502, p < 0.001; reference = non-smokers). Age was positively associated with Cd concentrations (β = 0.014, p < 0.001), and men showed lower concentrations than women (β = -0.424, p < 0.001). Obesity, measured as Body Mass Index (BMI), showed an inverse association with Cd concentrations (β = -0.038, p < 0.001). Egg consumption ≥2 portions/week (β = 0.241, p = 0.025) was positively associated with Cd concentrations. Perceived exposure to paints was also positively associated with Cd concentrations. The observed associations with age, smoking habit, BMI, and egg and meat consumption did not substantially change after sex/gender stratification. Our results are consistent with currently-known Cd sources and suggest other potential pathways, which might be population-specific. As a whole, our findings underline the potential relevance of adipose tissue as a biological matrix for exposure characterization to Cd, as well as for the assessment of long-term clinical implications of the exposure, particularly in obesity-related diseases.

Determination of Trace Elements in Adipose Tissue of Obese People by Microwave-Assisted Digestion and Inductively Coupled Plasma Optical Emission Spectrometry

In the present work, analytical method for the determination of trace elements in adipose tissue by means of inductively coupled plasma optical emission spectrometry (ICP-OES) was developed. Adipose tissue from two groups of the patients with obesity (with and without metabolic syndrome) was investigated. The main aim of this study was to reveal some differences and regularities in concentrations of trace elements in adipose tissue between these two groups of the individuals. Moreover, different types of adipose tissue (subcutaneous, preperitoneal, and visceral) were analyzed separately in order to investigate distribution of metals between these types in different groups of obese people. Al, Ba, Ca, Co, Cu, Cr, Fe, K, Li, Mg, Mn, Na, Ni, Sr, and Zn were selected for the quantitative determination. However, only 6 elements (Na, K, Ca, Fe, Mg, and Zn) were determined in all analyzed samples independently of the type of adipose tissue and presence of metabolic disorder of the patient. Concentrations of Ca, Fe, K, and Na were found to be strongly dependent on the type of adipose tissue. Other elements in terms of detection frequency in adipose tissue samples can be arranged in the following sequence Sr (94.7%), Cr (86.2%), Cu (24.6%), Li (18%), Ba (1.8%), Co (0.05%). The concentrations of Al, Mn, and Ni were found to be lower than limit of detection (LOD) in all analyzed samples. Comparison of metal distribution depending on the type of adipose tissue of people with and without metabolic syndrome is discussed in this work.

Socio-demographic, lifestyle, and dietary determinants of essential and possibly-essential trace element levels in adipose tissue from an adult cohort

There is increasing evidence linking levels of trace elements (TEs) in adipose tissue with certain chronic conditions (e.g., diabetes or obesity). The objectives of this study were to assess concentrations of a selection of nine essential and possibly-essential TEs in adipose tissue samples from an adult cohort and to explore their socio-demographic, dietary, and lifestyle determinants. Adipose tissue samples were intraoperatively collected from 226 volunteers recruited in two public hospitals from Granada province. Trace elements (Co, Cr, Cu, Fe, Mn, Mo, Se, V, and Zn) were analyzed in adipose tissue by high-resolution inductively coupled plasma mass spectrometry (HR-ICP-MS). Data were collected on socio-demographic characteristics, lifestyle, diet, and health status by face-to-face interview. Predictors of TE concentrations were assessed by using multivariable linear and logistic regression. All TEs were detected in all samples with the exception of Se (53.50%). Iron, zinc, and copper showed the highest concentrations (42.60 mg/kg, 9.80 mg/kg, and 0.68 mg/kg, respectively). Diet was the main predictor of Cr, Fe, Mo, and Se concentrations. Body mass index was negatively associated with all TEs (β coefficients = -0.018 to -0.593, p = 0.001-0.090) except for Mn and V. Age showed a borderline-significant positive correlation with Cu (β = 0.004, p = 0.089). Residence in a rural or semi-rural area was associated with increased Co, Cr, Fe, Mo, Mn, V and Zn concentrations and with β coefficients ranging from 0.196 to 0.544 (p < 0.05). Furthermore, individuals with higher educational level showed increased Cr, Co, Fe and V concentrations (β coefficients = 0.276-0.368, p = 0.022-0.071). This is the first report on the distribution of these TEs in adipose tissue and on their determinants in a human cohort and might serve as an initial step in the elucidation of their clinical relevance.

Synthesis of cytochrome c oxidase 1 (SCO1) inhibits insulin sensitivity by decreasing copper levels in adipocytes

Dysregulation of insulin signaling leads to type 2 diabetes mellitus (T2DM) and other metabolic disorders. Obesity is an important contributor to insulin resistance, and although the understanding of this relationship has improved in recent years, the mechanism of obesity-induced insulin resistance is not completely understood. Disorders of copper metabolism tend to accompany the development of obesity, which increases the risk of insulin resistance. Synthesis of cytochrome c oxidase 1 (SCO1) functions in the assembly of cytochrome c oxidase (COX) and cellular copper homeostasis. However, the role of SCO1 in the regulation of metabolism remains unknown. Here, we found that obese mice had higher expression of SCO1 and lower levels of copper in white adipose tissue (WAT) than did the control mice. Overexpression of SCO1 in adipocytes was associated with copper deficiency. Copper increased insulin sensitivity by decreasing the level of phosphatase and tensin homolog (PTEN) protein. Ectopic expression of SCO1 led to insulin resistance and was accompanied by a decrease in intracellular copper level, and addition of copper abolished the inhibitory effect of SCO1 on insulin sensitivity. Our results demonstrated a novel role of SCO1 in modulating insulin sensitivity via the regulation of copper concentration in WAT and suggested a potential therapeutic target for T2DM.

Comparative Analysis on the Effect of Plantago Species Aqueous Extracts on Tissue Trace Element Content in Rats

The primary objective of this study is to assess the influence of water extracts of Plantago major L., Plantago lanceolata L., and Plantago maxima Juss. ex Jacq. leaves on tissue trace element content in healthy adult Wistar rats. Twenty-eight female Wistar rats consumed pure drinking water or one of the three aqueous extracts of Plantago for 1 month. The extracts and liver, serum, hair, and adipose tissue of the rats were examined for trace element contents using inductively coupled plasma mass spectrometry. The aqueous extracts of Plantago species contained significant levels of trace elements, which were highest in P. lanceolata and P. major. The administration of every extract led to an increase in V and Si levels in the rats. At the same time, the consumption of P. lanceolata aqueous extract resulted in the accumulation of toxic elements (As, Pb) in the rats' tissues. Despite the rather high concentration of heavy metals in the P. major leaf extract, its administration did not result in the accumulation of these elements. In turn, P. maxima extract induced a significant decrease in the tissue levels of Al, Cr, I, Li, and Mn in the rats. The beneficial effect of the P. major and P. maxima preparations may be at least partially associated with the increased supply of essential trace elements, whereas the use of P. lanceolata may be harmful due to the possibility of heavy metal overexposure.

Early High-Fat Feeding Induces Alteration of Trace Element Content in Tissues of Juvenile Male Wistar Rats

The primary objective of the current study was to assess the influence of early high-fat feeding on tissue trace element content in young male Wistar rats. Twenty weanling male Wistar rats were divided into two groups fed standard (STD) or high-fat diet (HFD) containing 10 and 31.6 % of total calories from fat, respectively, for 1 month. Serum lipid spectrum, apolipoproteins, glucose, insulin, adiponectin, and leptin levels were assessed. The level of trace elements was estimated using inductively coupled plasma mass spectrometry. High-fat feeding significantly increased epidydimal (EDAT) and retroperitoneal adipose tissue (RPAT), as well as total adipose tissue mass by 34, 103, and 59 %, respectively. Serum leptin levels in HFD animals were twofold higher than those in the control rats. No significant difference in serum lipid spectrum, apolipoproteins, glucose, adiponectin, and insulin was detected between the groups. HFD significantly altered tissue trace element content. In particular, HFD-fed animals were characterized by significantly lower levels of Cu, I, Mn, Se, and Zn in the liver; Cr, V, Co, Cu, Fe, and I content of EDAT; Co, Cu, I, Cr, V, Fe, and Zn concentration in RPAT samples. At the same time, only serum Cu was significantly depressed in HFD-fed animals as compared to the control ones. Hair Co, Mn, Si, and V levels were significantly increased in comparison to the control values, whereas Se and I content was decreased. HFD feeding induced excessive adiposity and altered tissue trace element content in rats without insulin resistance, adiponectin deficiency, and proatherogenic state. Hypothetically, trace element disbalance may precede obesity-associated metabolic disturbances.