Contribution of Persistent Organic Pollutant Exposure to the Adipose Tissue Oxidative Microenvironment in an Adult Cohort: A Multipollutant Approach

Associations between blood levels of persistent organic pollutants and oxidative stress biomarkers among women in France in the 90's

Persistent organic pollutants (POPs) are a group of organic chemicals potentially toxic to human health. Induction of oxidative stress is one of the suspected mechanisms of action. The aims of this study were to model exposure-response functions between blood levels of a mixture of POPs and biomarkers of oxidative stress, to identify potential interactions between POPs, and to estimate the overall effect of the mixture. Levels of POPs and oxidative stress biomarkers were measured in the blood of 467 women from the French E3N cohort study, aged 45-73 years, collected between 1994 and 1999. In total, 41 POPs quantified in at least 75% of samples, and 3 antioxidant enzymes (Superoxide Dismutase 1 (SOD1), Superoxide Dismutase 2 (SOD2), and alpha-Glutathione S-Transferase (GSTα)) were included. A Bayesian Kernel Machine Regression (BKMR) model was fitted for each oxidative stress biomarker, including the 41 POPs as exposure variables and adjusting for potential confounders identified using a directed acyclic graph. Additionally, linear regression models including each POP biomarker separately adjusted for potential confounders were run. With the BKMR models, only two POPs biomarkers were found associated to SOD1 (PFPeS) and SOD2 (PCB-156). A greater number of POPs appeared associated to GSTα (oxychlordane, dieldrin, PFUnDA, PFHpA, PCB-28, PCB-153, PCB-180, PBDE-47, PBDE-100, and PBDE-153). Single-pollutant linear models also highlighted statistically significant associations in the same direction as the BKMR model. The BKMR models also highlighted non-linear cumulative effects, with overall negative trends for SOD1 and SOD2 and a positive trend for GSTα. These findings support that oxidative stress may be involved in the mechanisms linking the exposure of mixtures of POPs and related health effects. Further epidemiological studies on larger populations, as well as toxicological studies, are necessary to confirm these results.

Metabolic Signatures in Adipose Tissue Linking Lipophilic Persistent Organic Pollutant Mixtures to Blood Pressure Five Years After Bariatric Surgery Among Adolescents

Persistent organic pollutants (POPs) are lipophilic environmental contaminants accumulated in the adipose tissue. Weight loss interventions, such as bariatric surgery, can mobilize POPs from adipose tissue into the bloodstream. We hypothesized that this mobilization could contribute to increases in blood pressure among 57 adolescents with severe obesity undergoing bariatric surgery. POPs and metabolic features were measured from visceral adipose tissue collected during surgery using gas and liquid chromatography, coupled with high-resolution mass spectrometry. Blood pressure was assessed at baseline, 6 months, and 5 years post-surgery. We used quantile g-computation to estimate associations of POP mixtures with blood pressure changes. With one quartile increase in POP mixtures, systolic blood pressure (SBP) increased by 6.4% five years after bariatric surgery compared to baseline SBP [95% confidence interval (CI): 0.4%, 12.4%]. The meet-in-the-middle approach identified overlapping metabolic features and pathways linking POP mixtures to SBP changes, highlighting the role of prostaglandin formation via arachidonic acid metabolism. POP mixtures were negatively associated with indole-3-acetate (-0.729, 95% CI: -1.234, -0.223), which was negatively associated with SBP changes at five years (-3.49%, 95% CI: -6.51%, -0.48%). Our findings suggested that lipophilic POP mixtures attenuated the beneficial effect of bariatric surgery on improved blood pressure among adolescents via alterations in lipid metabolism.

Non-dioxin-like polychlorinated biphenyls (PCB 101, 153, and 180) and adipocyte lipid dysfunctions: Involvement of glycerol and role of aquaglyceroporins in mature 3T3-L1 cells

Non-dioxin-like polychlorinated biphenyls (NDL-PCBs), as well as dioxin-like PCBs, are endocrine disruptors that persist in human and animal tissues worldwide. Due to their lipophilicity and resistance to enzymatic degradation, PCBs accumulate in fat deposits contributing to the onset of endocrine and metabolic diseases. Aquaporins (AQPs) are transmembrane channel proteins that allow the transport of water and small solutes. In particular, the aquaglyceroporins AQP3, AQP7, and AQP9 mediate the release and the uptake of glycerol in adipose tissue. Here, we investigate the modulation of these AQPs by NDL-PCBs and the following effects on lipid metabolism in mature 3T3-L1 adipocytes exposed for 48 h to PCB 101, 153, or 180 (1 μM). NDL-PCBs modulated protein expression of AQP3 and AQP7, involved in glycerol release, and AQP9, implicated in glycerol uptake. This modulation induced a greater accumulation of glycerol in treated adipocytes indirectly evaluated by its reduction in the culture media. Interestingly, only PCB 153 altered the expression of enzymes involved in glycerol metabolism and lipid accumulation (i.e. Pparg, Fabp4, Gyk, Dgat1, and Agpat9). These modifications indicated an increase of adipocyte lipid accumulation confirmed by Oil Red O staining. The role of AQPs in the increased cellular accumulation of glycerol was confirmed using phloretin, an AQP9 inhibitor, that reverted the PCB 153 effect. Our results show the involvement of AQPs in PCB 153-induced dysfunction of glycerol metabolism and lipid storage in adipocytes, contributing to better defining the mechanisms underlying its known obesogenic effect.

Association between exposure to a mixture of organochlorine pesticides and hyperuricemia in U.S. adults: A comparison of four statistical models

The association between the exposure of organochlorine pesticides (OCPs) and serum uric acid (UA) levels remained uncertain. In this study, to investigate the combined effects of OCP mixtures on hyperuricemia, we analyzed serum OCPs and UA levels in adults from the National Health and Nutrition Examination Survey (2005-2016). Four statistical models including weighted logistic regression, weighted quantile sum (WQS), quantile g-computation (QGC), and bayesian kernel machine regression (BKMR) were used to assess the relationship between mixed chemical exposures and hyperuricemia. Subgroup analyses were conducted to explore potential modifiers. Among 6,529 participants, the prevalence of hyperuricemia was 21.15%. Logistic regression revealed a significant association between both hexachlorobenzene (HCB) and trans-nonachlor and hyperuricemia in the fifth quintile (OR: 1.54, 95% CI: 1.08-2.19; OR: 1.58, 95% CI: 1.05-2.39, respectively), utilizing the first quintile as a reference. WQS and QGC analyses showed significant overall effects of OCPs on hyperuricemia, with an OR of 1.25 (95% CI: 1.09-1.44) and 1.20 (95% CI: 1.06-1.37), respectively. BKMR indicated a positive trend between mixed OCPs and hyperuricemia, with HCB having the largest weight in all three mixture analyses. Subgroup analyses revealed that females, individuals aged 50 years and above, and those with a low income were more vulnerable to mixed OCP exposure. These results highlight the urgent need to protect vulnerable populations from OCPs and to properly evaluate the health effects of multiple exposures on hyperuricemia using mutual validation approaches.

Association between exposure to per- and polyfluoroalkyl substance and liver injury in American adults

Epidemiological data is scarce regarding the association between exposure to mixtures of per- and polyfluoroalkyl substances (PFASs) and liver injury in the general populace. The current research used data from the National Health and Nutrition Examination Survey (2009-2018). The PFAS exposure levels were defined by the serum concentrations of PFASs with > 70% detection in samples, namely perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorohexane sulfonic acid (PFHxS), perfluorodecanoic acid (PFDeA), and perfluorooctane sulfonic acid (PFOS). Liver injury was assessed from two aspects: first, the degree of liver inflammation was determined based on serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), glutamyltransferase (GGT), and total bilirubin (TBIL) levels; second, the degree of liver fibrosis was determined based on fibrosis-4 (FIB-4) index. We assessed the associations between individual or total PFAS exposure and these outcomes using multivariable linear regression models and logistic regression models, restricted cubic splines, and weighted quantile sum regression. Among the samples of 7484 American adults, the median concentration of PFOS was the highest, followed by PFOA and PFHxS. Using multivariable linear regression, a positive correlation was observed between all PFASs and liver enzymes such as ALT, AST, and TBIL. Additionally, the weighted quantile sum model indicated an overall positive association between the five PFASs and liver injury indicators. For liver function biomarkers and liver fibrosis, PFNA and PFOS were the most heavily weighting chemicals, respectively. Our findings provide new epidemiological evidence indicating a potential association between PFAS exposure and adverse effects on liver injury biomarkers, highlighting the potentially harmful effects of PFAS exposure on liver health.

Serum Phthalate Concentrations and Biomarkers of Oxidative Stress in Adipose Tissue in a Spanish Adult Cohort

The relationship between phthalates, a group of chemical pollutants classified as endocrine disruptors, and oxidative stress is not fully understood. The aim of the present hospital-based study was to explore the associations between circulating levels of 10 phthalate metabolites and 8 biomarkers of oxidative stress in adipose tissue. The study population (n = 143) was recruited in two hospitals in the province of Granada (Spain). Phthalate metabolite concentrations were analyzed by isotope diluted online-TurboFlow-LC-MS/MS in serum samples, while oxidative stress markers were measured by commercially available kits in adipose tissue collected during routine surgery. Statistical analyses were performed by MM estimators' robust linear regression and weighted quantile sum regression. Mainly, positive associations were observed of monomethyl phthalate (MMP), monoiso-butyl phthalate (MiBP), and mono-n-butyl phthalate (MnBP) (all low molecular weight phthalates) with glutathione peroxidase (GPx) and thiobarbituric acid reactive substances (TBARS), while an inverse association was found between monoiso-nonyl phthalate (MiNP) (high molecular weight phthalate) and the same biomarkers. WQS analyses showed significant effects of the phthalate mixture on GSH (β = -30.089; p-value = 0.025) and GSSG levels (β = -19.591; p-value = 0.030). Despite the limitations inherent to the cross-sectional design, our novel study underlines the potential influence of phthalate exposure on redox homeostasis, which warrants confirmation in further research.

Association between mixed exposure to endocrine-disrupting chemicals and cognitive function in elderly Americans

OBJECTIVES

Studies exploring the relationship between mixed exposure to endocrine-disrupting chemicals (EDCs) and cognition are limited, with even more scarce studies conducted in the elderly. The aim of this study was to investigate the association between mixed exposure to five categories of EDCs and cognition in elderly Americans.

STUDY DESIGN

Cross-sectional study.

METHODS

727 participants from the 2011-2014 National Health and Nutrition Examination Survey were incorporated into this study, and the levels of 47 EDC metabolites were measured. Cognitive function was assessed using immediate recall test (IRT), delayed recall test (DRT), animal fluency test (AFT), and digit symbol substitution test (DSST), and all the cognitive test scores were standardized. The individual and combined effects of EDC metabolites on the cognitive function in older adults were assessed using three analytical methods.

RESULTS

The results showed that exposure to perfluorononanoic acid, polychlorinated biphenyl (PCB) 199, and PCB 206 was associated with the z-scores on the cognitive tests. Negative associations between mixed exposure to EDCs and the AFT and Global z-scores and a positive relationship with the DRT z-score were found in the WQS regression. The BKMR results revealed a positive trend between the mixture of EDCs and the DRT z-score. However, compared to the median, exposure to mixtures in the 45th percentile and below was associated with a decreased DRT z-score.

CONCLUSIONS

Mixed exposure to EDCs may adversely affect the global cognitive function in elderly individuals. Necessary measures are needed to restrict EDCs use to protect the cognitive health of older adults.

Association between plasma and dietary trace elements and obesity in a rural Chinese population

Trace elements may play an important role in obesity. This study aimed to assess the plasma and dietary intake levels of four trace elements, Mn, Cu, Zn and Se in a rural Chinese population, and analyse the relationship between trace elements and obesity. A cross-sectional study involving 2587 participants was conducted. Logistic regression models were used to analyse the association between trace elements and obesity; restricted cubic spline (RCS) models were used to assess the dose-response relationship between trace elements and obesity; the weighted quantile sum (WQS) model was used to examine the potential interaction of four plasma trace elements on obesity. Logistic regression analysis showed that plasma Se concentrations in the fourth quartile (Q4) exhibited a lower risk of developing obesity than the first quartile (Q1) (central obesity: OR = 0·634, P = 0·002; general obesity: OR = 0·525, P = 0·005). Plasma Zn concentration in the third quartile (Q3) showed a lower risk of developing obesity in general obesity compared with the first quartile (Q1) (OR = 0·625, P = 0·036). In general obesity, the risk of morbidity was 1·727 and 1·923 times higher for the second and third (Q2, Q3) quartiles of dietary Mn intake than for Q1, respectively. RCS indicated an inverse U-shaped correlation between plasma Se and obesity. WQS revealed the combined effects of four trace elements were negatively associated with central obesity. Plasma Zn and Se were negatively associated with obesity, and dietary Mn was positively associated with obesity. The combined action of the four plasma trace elements had a negative effect on obesity.

Associations of per- and polyfluoroalkyl substances, polychlorinated biphenyls, organochlorine pesticides, and polybrominated diphenyl ethers with oxidative stress markers: A systematic review and meta-analysis

BACKGROUND

Per- and polyfluoroalkyl substances (PFAS), polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), and polybrominated diphenyl ethers (PBDEs) are intentionally produced persistent organic pollutants (POPs) that are resistant to environmental degradation. Previous in-vitro and in-vivo studies have shown that POPs can induce oxidative stress, which is linked to neurodegenerative diseases, cardiovascular diseases, and cancer. However, findings in epidemiological studies are inconsistent and an evidence synthesis study is lacking to summarize the existing literature and explore research gaps.

OBJECTIVE

We evaluated the effects of PFAS, PCBs, OCPs, and PBDEs, on oxidative stress biomarkers in epidemiological studies.

METHODS

A literature search was conducted in PubMed, Embase, and Cochrane CENTRAL to identify all published studies related to POPs and oxidative stress up to December 7th, 2022. We included human observational studies reporting at least one exposure to POPs and an oxidative stress biomarker of interest. Random-effects meta-analyses on standardized regression coefficients and effect direction plots with one-tailed sign tests were used for quantitative synthesis.

RESULTS

We identified 33 studies on OCPs, 35 on PCBs, 49 on PFAS, and 12 on PBDEs. Meta-analyses revealed significant positive associations of α-HCH with protein carbonyls (0.035 [0.017, 0.054]) and of 4'4-DDE with malondialdehyde (0.121 [0.056, 0.187]), as well as a significant negative association between 2'4-DDE and total antioxidant capacity (TAC) (-0.042 [-0.079, -0.004]), all β [95%CI]. Sign tests showed a significant positive association between PCBs and malondialdehyde (pone-tailed = 0.03). Additionally, we found significant negative associations of OCPs with acetylcholine esterase (pone-tailed = 0.02) and paraoxonase-1 (pone-tailed = 0.03). However, there were inconsistent associations of OCPs with superoxide dismutase, glutathione peroxidase, and catalase.

CONCLUSIONS

Higher levels of OCPs were associated with increased levels of oxidative stress through increased pro-oxidant biomarkers involving protein oxidation, DNA damage, and lipid peroxidation, as well as decreased TAC. These findings have the potential to reveal the underlying mechanisms of POPs toxicity.

Associations of polychlorinated biphenyl and organochlorine pesticide exposure with hyperuricemia: modification by lifestyle factors

Recent research has reported positive associations of exposure to polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) with hyperuricemia. However, most of these studies have primarily focused on the individual effects of PCB/OCP exposure. We aimed to explore the associations of both individual and combined PCB/OCP exposure with hyperuricemia and examine whether such associations could be modified by lifestyle factors. The cross-sectional study recruited 2032 adults between March and May 2019 in Wuhan, China. Logistic regression and weighted quantile sum (WQS) regression were applied to explore the relationship of individual and combined PCB/OCP exposure with hyperuricemia, while considering the modified effects of lifestyle factors. Of the 2032 participants, 522 (25.7%) had hyperuricemia. Compared with the non-detected group, the detected groups of PCB153 and PCB180 exhibited a positive association with hyperuricemia, with OR (95% CIs) of 1.52 (1.22, 1.91) and 1.51 (1.20, 1.90), respectively. WQS regression showed that PCB/OCP mixture was positively associated with hyperuricemia (OR: 1.31, 95% CI: 1.08, 1.58). PCB153/PCB180 exposure, combined with an unhealthy lifestyle, has a significant additive effect on hyperuricemia. Overall, PCB/OCP mixture and individual PCB153/PCB180 exposure were positively associated with hyperuricemia. Adherence to a healthy lifestyle may modify the potential negative impact of PCBs/OCPs on hyperuricemia.

Cross-sectional associations of persistent organic pollutants measured in adipose tissue and metabolic syndrome in clinically diagnosed middle-aged adults

INTRODUCTION

Although often overlooked in clinical settings, accumulation of persistent organic pollutants (POPs) in visceral adipose tissue (VAT) is thought to be a relevant risk factor for metabolic syndrome (MetS).

METHODS

One hundred and seventeen patients undergoing non-oncological surgery were randomly recruited and classified as MetS + if presented 3 out of the 5 MetS components: waist circumference (WC), systolic and diastolic blood pressure (SBP and DBP, respectively), serum glucose, insulin, triglycerides (TG) and high-density lipoprotein (HDL) cholesterol levels, according International Diabetes Federation (IDF) criteria. Seventeen organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) were measured in adipose tissue samples. Linear, logistic and weighted quantile sum (WQS) regression models, adjusted for age and sex, were performed.

RESULTS

One third of the participants were males (36.8%) with a median age of 44 years, showing clinical evidences of MetS (35.0%). Adjusted linear regression models showed that WC correlated positively with all OCP concentrations. Higher fasting serum glucose levels were related to higher HCB and γ-HCH concentrations. The remaining OCPs and PCBs were not associated with this MetS component. HCB was inversely associated with HDL cholesterol levels, while PCB-180 was positively associated. HCB and γ-HCH concentrations were also positively correlated with DBP and SBP levels. PCB-138 was also positively associated with SBP. Adjusted logistic models revealed that exposure to HCB and γ-HCH were associated with increased odds of MetS [ORs (95%CI) 1.53 (1.22-1.92) and 1.39 (1.10-1.76) respectively; p < 0.01]. No associations were observed for the remaining POPs. WQS models showed a positive and significant mixture effect of POPs on the odds of MetS (exp [beta] = 2.34; p < 0.001), with γ-HCH (52.9%), o,p'-DDT (26.9%) and HCB (19.7%) driving the association.

CONCLUSIONS

Our findings support that POPs accumulated in VAT, specifically HCB and (gamma)-HCH, are associated with both isolated components and clinically diagnosed SMT.

Association between exposure to a mixture of metals, parabens, and phthalates and fractional exhaled nitric oxide: A population-based study in US adults

The effects of environmental endocrine-disrupting chemicals (EDCs) (e.g., phthalates) on fractional exhaled nitric oxide (FeNO) in children have received much attention. However, few studies evaluated this relationship in adults, and the previous studies have considered only a unitary exposure or a set of similar exposures instead of mixed exposures, which contain complicated interactions. We aimed to evaluate simultaneously the relationship between three types of EDCs (six phthalate metabolites and two parabens in urine, two heavy metals in blood) and FeNO (as a continuous variable) in adults. Data of adults aged ≥20 years from the National Health and Nutrition Examination Survey (NHANES, 2007-2012) were collected and analyzed. The generalized linear (GLM) regression model was used to explore the association of chemicals with FeNO. The combined effect of 10 chemicals on the overall association with FeNO was evaluated by the weighted quantile sum regression (WQS) model. In addition, The Bayesian kernel machine regression (BKMR) model was explored to investigate the interaction and joint effects of multiple chemicals with FeNO. Of the 3296 study participants ultimately included, among the GLMs, we found that mercury (Hg) (β = 0.84, 95%CI:0.32-1.36, FDR = 0.01) and methyl paraben (MPB) (β = 0.47, 95%CI:0.16-0.78, FDR = 0.015) were positively correlated with FeNO. In the WQS model, the combined effect of chemicals almost had a significantly positive association with FeNO and the top three contributors to the WQS index were Hg (40.2%), MECPP (22.1%), and MPB (19.3%). BKMR analysis showed that there may be interactions between MPB and Hg, Mono (carboxyoctyl) phthalate (MCOP) and Hg and the overall effect of the mixture showed a positive correlation with FeNO. In conclusion, our study strengthens the credibility of the view that EDCs can affect respiratory health. In the future, we should be particularly careful with products containing Hg, MECPP, MPB, and MEHP for the prevention of respiratory diseases.

Low-Dose Dioxin Reduced Glucose Uptake in C2C12 Myocytes: The Role of Mitochondrial Oxidative Stress and Insulin-Dependent Calcium Mobilization

Chronic exposure to some environmental polluting chemicals (EPCs) is strongly associated with metabolic syndrome, and insulin resistance is a major biochemical abnormality in the skeletal muscle in patients with metabolic syndrome. However, the causal relationship is inconsistent and little is known about how EPCs affect the insulin signaling cascade in skeletal muscle. Here, we investigated whether exposure to 100 pM of 2,3,7,8-tetrachlorodibenzodioxin (TCDD) as a low dose of dioxin induces insulin resistance in C2C12 myocytes. The treatment with TCDD inhibited the insulin-stimulated glucose uptake and translocation of glucose transporter 4 (GLUT4). The low-dose TCDD reduced the expression of insulin receptor β (IRβ) and insulin receptor substrate (IRS)-1 without affecting the phosphorylation of Akt. The TCDD impaired mitochondrial activities, leading to reactive oxygen species (ROS) production and the blockage of insulin-induced Ca2+ release. All TCDD-mediated effects related to insulin resistance were still observed in aryl hydrocarbon receptor (AhR)-deficient myocytes and prevented by MitoTEMPO, a mitochondria-targeting ROS scavenger. These results suggest that low-dose TCDD stress may induce muscle insulin resistance AhR-independently and that mitochondrial oxidative stress is a novel therapeutic target for dioxin-induced insulin resistance.

Adaptive-mixture-categorization (AMC)-based g-computation and its application to trace element mixtures and bladder cancer risk

Several new statistical methods have been developed to identify the overall impact of an exposure mixture on health outcomes. Weighted quantile sum (WQS) regression assigns the joint mixture effect weights to indicate the overall association of multiple exposures, and quantile-based g-computation is a generalized version of WQS without the restriction of directional homogeneity. This paper proposes an adaptive-mixture-categorization (AMC)-based g-computation approach that combines g-computation with an optimal exposure categorization search using the F statistic. AMC-based g-computation reduces variance within each category and retains the variance between categories to build more powerful predictors. In a simulation study, the performance of association analysis was improved using categorizing by AMC compared with quantiles. We applied this method to assess the association between a mixture of 12 trace element concentrations measured from toenails and the risk of non-muscle invasive bladder cancer. Our findings suggested that medium-level (116.7-145.5 μg/g) vs. low-level (39.5-116.2 μg/g) of toenail zinc had a statistically significant positive association with bladder cancer risk.

Public healthcare costs associated with long-term exposure to mixtures of persistent organic pollutants in two areas of Southern Spain: A longitudinal analysis

BACKGROUND

Polychlorinated biphenyls and organochlorine pesticides are persistent organic pollutants (POPs) that had been banned or restricted in many countries, including Spain. However, their ubiquity still poses environmental and human health threats.

OBJECTIVE

To longitudinally explore public healthcare costs associated with long-term exposure to a mixture of 8 POPs in a cohort of residents of two areas of Granada Province, Southern Spain.

METHODS

Longitudinal study in a subsample (n = 385) of GraMo adult cohort. Exposure assessment was performed by analyzing adipose tissue POP concentrations at recruitment. Average primary care (APC) and average hospital care (AHC) expenditures of each participant over 14 years were estimated using the data from their medical records. Data analyses were performed by robust MM regression, weighted quantile sum regression (WQS) and G-computation analysis.

RESULTS

In the adjusted robust MM models for APC, most POPs showed positive beta coefficients, being Hexachlorobenzene (HCB) significantly associated (β: 1.87; 95% Confidence interval (95%CI): 0.17, 3.57). The magnitude of this association increased (β: 3.72; 95%CI: 0.80, 6.64) when the analyses were restricted to semi-rural residents, where β-HCH was also marginally-significantly associated to APC (β: 3.40; 95%CI: -0.10, 6.90). WQS revealed a positive but non-significant mixture association with APC (β: 0.14; 95%CI: -0.06, 0.34), mainly accounted for by β-HCH (54%) and HCB (43%), that was borderline-significant in the semi-rural residents (β: 0.23; 95%CI: -0.01, 0.48). No significant results were observed in G-Computation analyses.

CONCLUSION

Long-term exposure to POP mixtures might represent a modifiable factor increasing healthcare costs, thus affecting the efficiency of the healthcare systems. However, and owing the complexity of the potential causal pathways and the limitations of the present study, further research is warranted to fully elucidate ascertain whether interventions to reduce human exposure should be considered in healthcare policies.

Differential Bioaccumulation Patterns of α, β-Hexachlorobenzene and Dicofol in Adipose Tissue from the GraMo Cohort (Southern Spain)

To identify bioaccumulation patterns of α-, β- hexachlorocyclohexane (HCH) and dicofol in relation to sociodemographic, dietary, and lifestyle factors, adipose tissue samples of 387 subjects from GraMo cohort in Southern Spain were analyzed. Potential predictors of these organochlorine pesticides (OCP) levels were collected by face-to-face interviews and assessed by multivariable linear and logistic regression. OCPs were detected in 84.2% (β-HCH), 21.7% (α-HCH), and 19.6% (dicofol) of the population. β-HCH levels were positively related to age, body mass index (BMI), mother's occupation in agriculture during pregnancy, living in Poniente and Alpujarras, white fish, milk and water consumption, and negatively related to being male, living near to an agricultural area, working ≥10 years in agriculture, and beer consumption. Detectable α-HCH levels were positively related to age, BMI, milk consumption, mother's occupation in agriculture during pregnancy, and negatively with residence in Poniente and Alpujarras, Granada city, and Granada Metropolitan Area. Residence near to an agricultural area, smoking habit, white fish and water consumption, and living in Poniente and Alpujarras, Granada city and Granada Metropolitan Area were negatively associated with detectable dicofol levels. Our study revealed different bioaccumulation patterns of α, β-HCH and dicofol, probably due to their dissimilar period of use, and emphasize the need for assessing the exposure to frequently overlooked pollutants.

Health risk assessment of exposure to organochlorine pesticides in the general population in Seoul, Korea over 12 years: A cross-sectional epidemiological study

This study evaluated the 12-year trends in serum levels of 28 organochlorine pesticides (OCPs) in 880 adults living in Seoul, Korea. The OCP levels decreased from 2006 to 2017, and p,p'-dichlorodiphenyldichloroethylene was a predominant compound. OCP levels were higher in females than in males, and showed positive associations with BMI and age. The OCP concentrations had inverted U-shaped associations with low-density lipoprotein cholesterol and total cholesterol. Concentrations of β-hexachlorocyclohexane were significantly higher in patients with hypertension than in participants that were normotensive. OCP levels showed positive associations with uric acid, creatinine, and thyroid-stimulating hormone, but negative associations with free thyroxine. Participants with diabetes had significantly higher OCP levels than those without it. Principal component analysis suggested possible differences in disease manifestation depending on the composition of OCPs. These results suggest that OCPs might disturb renal transport and thyroid homeostasis. To our knowledge, the inverted U-shaped associations of heptachlor epoxide and endosulfan with cholesterol, the epidemiological associations of trans-nonachlor and endosulfan with thyroid hormones, and the association of p,p'-DDE with hyperuricemia have not been previously reported in general population. This is the first long-term study to show trends of 28 OCPs in serum and associations with various health indicators in Korea.

Historical exposure to persistent organic pollutants and cardiovascular disease: A 15-year longitudinal analysis focused on pharmaceutical consumption in primary care

BACKGROUND

Despite restrictions on their production and use, most of the population is still exposed to Persistent Organic Pollutants (POPs), including organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs). These chemicals are thought to contribute to the aetiology of highly prevalent chronic conditions, such as cardiovascular diseases (CVDs), although current evidences are still controversial.

OBJECTIVES

To explore the potential contribution of historical POP exposure to 15-year pharmaceutical consumption in relation to CVD.

METHODS

This study is framed within GraMo adult cohort. Participants (n = 387) were recruited in two hospitals in Granada province, Southern Spain (2003-2004). Historical exposure to 5 OCPs and 3 non-dioxine-like PCBs was estimated by analysing adipose tissue concentrations at recruitment. Pharmaceutical consumption from recruitment until year 2017 was quantified by reviewing dispensation databases. Average consumption increase (ACI) in CVD medication was calculated by subtracting average consumption in 2002 to the average yearly consumption during follow-up. ACI was expressed as Defined Daily Dose (DDD)/year units. Data analyses were carried out using a multivariable multinomial logistic regression and weighted quantile sum regression (WQS), with ACI categorized in quartiles (Q) as the dependent variable.

RESULTS

Concentrations of most pollutants showed a positive trend with the quartiles of ACI. Particularly, PCB-153 showed increasing and statistically significant odds ratios (ORs) for Q2 (OR: 1.27, 95% confidence interval (CI): 1.07-1.52), Q3 (OR: 1.49, 95 %CI: 1.17-1.88) and Q4 (OR: 1.42, 95 %CI: 1.13-1.78) vs Q1. Similarly, beta-hexachlorocyclohexane (β-HCH) also showed increasing ORs, that reached statistical significance in Q4 (OR: 1.36, 95 %CI: 1.06-1.74) vs Q1. These findings were corroborated by WQS analyses, that revealed a significant mixture effect, predominantly accounted for by PCB-153 and β-HCH.

DISCUSSION

Our results suggest that long-term POP exposure might represent a modifiable risk factor for CVD. These findings are relevant for public health campaigns and management, since pharmaceutical consumption is considered an indicator of both morbidity and health expenditure.

Associations of accumulated selected persistent organic pollutants in adipose tissue with insulin sensitivity and risk of incident type-2 diabetes

Continuous exposure to low doses of persistent organic pollutant (POPs), such as those occurring in the general population, might contribute to the burden of type 2 diabetes mellitus (T2DM). However, evidences from longitudinal studies are scarce. We aimed to explore the associations of accumulated POP exposure with the development of T2DM by means of 1) longitudinal associations with the 16-year incidence of the disease, and 2) complementary cross-sectional analyses with markers of glucose homeostasis at recruitment. Organochlorine pesticide and polychlorinated biphenyl (PCB) concentrations were analyzed in adipose tissue samples and incident T2DM cases were retrieved from clinical records. Homeostatic model assessment values of insulin sensitivity/resistance and β-cell function at recruitment were calculated. Linear and Cox-regression models were performed. In individuals with normal weight/overweight (n = 293), we observed positive dose-response relationships between the studied POPs and T2DM risk, particularly for hexachlorobenzene (HCB) [hazard ratio (HR): 3.96 for 4th quartile versus 1st quartile (Q1); confidence interval (CI) 95%: 0.79, 19.71]. PCB-180 showed a positive but seemingly non-linear association with T2DM risk [HR of 3^er quartile (Q3) versus Q1: 6.48; CI 95%: 0.82, 51.29]. Unadjustment for body mass index considerably increased the magnitude of the associations. In the cross-sectional study (n = 180), HCB and PCB-180 were inversely associated with insulin sensitivity and positively associated with insulin resistance parameters. Our results suggest that a higher burden of specific POPs in adipose tissue may disrupt glucose homeostasis, possibly contributing to increase T2DM risk, especially in non-obese adults.

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.

Adipose Tissue Redox Microenvironment as a Potential Link between Persistent Organic Pollutants and the 16-Year Incidence of Non-hormone-Dependent Cancer

We aimed to assess the relationships among the adipose tissue's (AT) oxidative microenvironment, in situ accumulated persistent organic pollutant (POP) concentrations, and cancer development. POP and oxidative stress levels were quantified in AT samples from 382 adults recruited within the GraMo cohort (2003-2004) in Granada (Spain). The 16-year cancer incidence was ascertained by reviewing health/administrative databases. Cox-regression models and mediation analyses were performed. The enzymes superoxide dismutase (SOD) and glutathione reductase (GRd) were positively associated with the risk of non-hormone-dependent (NHD) cancer [adjusted hazard ratio (HR) 1.76; 95% confidence interval (CI): 1.17, 2.64 and HR 2.35; 95% CI: 1.41, 3.94, respectively]. After adjustment for covariates, polychlorinated biphenyl-138 (PCB-138) (HR 1.78; 95% CI: 1.03, 3.09), β-hexachlorocyclohexane (β-HCH) (HR 1.70; 95% CI: 1.09, 2.64), and hexachlorobenzene (HR 1.54; 95% CI: 1.02, 2.33) were also positively associated with the risk of NHD cancer. Although confidence intervals included the null value, probably because of the modest number of cancer cases, we observed a potential mediation effect of SOD and GRd on the associations between β-HCH and the risk of NHD tumors (percent mediated = 33 and 47%, respectively). Our results highlight the relevance of human AT's oxidative microenvironment as a predictor of future cancer risk as well as its potential mediating role on POP-related carcinogenesis. Given their novelty, these findings should be interpreted with caution and confirmed in future studies.

Associations of persistent organic pollutants in human adipose tissue with retinoid levels and their relevance to the redox microenvironment

Humans are exposed to a myriad of chemical substances in both occupational and environmental settings. Persistent organic pollutants (POPs) have drawn attention for their adverse effects including cancer and endocrine disruption. Herein, the objectives were 1) to describe serum and adipose tissue retinol levels, along with serum retinol binding protein 4 (RBP4) concentrations, and 2) to assess the associations of adipose tissue POP levels with these retinoid parameters, as well as their potential interaction with the previously-observed POP-related disruption of redox microenvironment. Retinol was measured in both serum and adipose tissue along with RBP4 levels in serum samples of 236 participants of the GraMo adult cohort. Associations were explored by multivariable linear regression analyses and Weighted Quantile Sum regression. Polychlorinated biphenyls (PCBs) 180, 153 and 138 were related to decreased adipose tissue retinol levels and increased serum RBP4/retinol ratio. Dicofol concentrations > limit of detection were associated with decreased retinol levels in serum and adipose tissue. Additionally, increased adipose tissue retinol levels were linked to an attenuation in previously-reported associations of adipose tissue PCB-153 with in situ superoxide dismutase activity. Our results revealed a suggestive link between retinoids, PCBs and redox microenvironment, potentially relevant for both mechanistic and public health purposes.

Emerging POPs-type cocktail signatures in Pusa caspica in quantitative structure-activity relationship of Caspian Sea

The Caspian seal Pusa caspica is the only endemic mammalian species throughout the Caspian Sea. This is the first report on risk assessment of persistent organic pollutants (POPs) in Caspian seals by age-sex and tissue-specific uptake, and their surrounding environment (seawater, surface sediments, and suspended particulate matters, SPMs) in the Gorgan Bay (Caspian Sea, Iran). Among the quantified 70 POPs (∑₃₅PCBs, ∑₃HCHs, ∑₆CHLs, ∑₆DDTs, ∑₁₇PCDD/Fs, HCB, dieldrin, and aldrin), ∑₃₅PCBs were dominant in abiotic matrices (48.80% of ∑₇₀POPs), followed by HCHs > CHLs > DDTs > PCDD/Fs > other POPs in surface sediments > SPMs > seawater, while the toxic equivalent quantity (TEQ_WHO) exceeded the safe value (possible risk in this area). In biota, the highest levels of ∑₇₀POPs were found in males (756.3 ng g^-1 dw, p < 0.05), followed by females (419.0 ng g^-1 dw) and pups (¹91.6 ng g^-1 dw) in liver > kidney > muscle > blubber > intestine > fur > heart > spleen > brain. The positive age-related POPs declining correlation between mother-pup pairs suggested the possible maternal transfer of POPs to offspring. The cocktail toxicity assessment revealed that Caspian seals can pose a low risk based on their mixed-TEQ values. Self-organizing map (SOM) indicated the non-coplanar PCB-93 as the most over-represented functional congener in tissue-specific POPs bioaccumulation. Quantitative toxicant tissue-profiling is valuable for predicting the state of mixture toxicity in pinniped species.

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.

HDL cholesterol: A potential mediator of the association between urinary cadmium concentration and cardiovascular disease risk

Evidence from previous studies has shown that exposure to metals is associated with cardiovascular disease (CVD). However, the association between metal mixtures and CVD risk and the potential mechanisms in epidemiologic studies remain unclear. The data of 14,795 adults who participated in the U.S. National Health and Nutrition Examination Survey (NHANES) 1999-2016 were analyzed. Multivariate logistic regression was performed to investigate the associations between urinary metal levels and CVDs. Weighted quantile sum (WQS) regression was performed to examine the effects of mixed metals on CVDs. Multivariate linear regression and mediation analysis were conducted to explore the associations between metals and blood lipids. Urinary cadmium (Cd) was significantly associated with an increased total CVD risk and with individual CVD risk. The odds ratio (OR) for CVD in the highest quartile of the WQS index was 1.43 (95% confidence interval [CI]: 1.19, 1.71). One augmented urinary Cd concentration unit (Log10) was associated with a 0.93 mg/dL decrease in HDL cholesterol, a 1.34 mg/dL increase in LDL cholesterol and a 1.30 mg/dL increase in total cholesterol in the fully adjusted model. Mediation analysis showed that HDL cholesterol mediated 4.91% of the association between urinary Cd and the prevalence of CVD. Our findings suggest that urinary Cd and metal mixtures were significantly and positively associated with CVD. The downregulation of HDL cholesterol might play a significant role in mediating Cd exposure-associated CVD risk increases.

Combined Exposure to Multiple Endocrine Disruptors and Uterine Leiomyomata and Endometriosis in US Women

BACKGROUND

Uterine leiomyomata (UL) and endometriosis (EM) are common gynecological diseases damaging the reproductive health of fertile women. Among all the potential factors, environmental endocrine-disrupting chemicals are insufficiently addressed considering the multiple pollutants and mixture exposure.

METHODS

Women aged 20 to 54 years old in the National Health and Nutrition Examination Survey (NHANES) 2001-2006, having a complete measurement of ten commonly exposed endocrine-disrupting chemicals (including urinary phthalate metabolites, equol, and whole blood heavy metals) and answered questions about UL and EM were included (N=1204). Multivariable logistic regression model, weighted quantile sum (WQS) regression, and Bayesian kernel machine regression (BKMR) models were implemented to analyze the combined effect of chemicals on the overall association with UL and EM.

RESULTS

In single chemical analysis, equol (OR: 1.90, 95% CI: 1.11, 3.27) and mercury (Hg) (OR: 1.91, 95% CI: 1.14, 3.25) were found positively associated with UL in tertile 3 vs. tertile 1. In WQS regression and BKMR models, the significant positive association between WQS index and UL (OR: 2.54, 95% CI: 1.52, 4.29) was identified and the positive relationship between equol and Hg exposure and UL were further verified. Besides, the mixture evaluation models (WQS and BKMR) also found MEHP negatively associated with UL. Although none of the single chemicals in tertile 3 were significantly associated with EM, the WQS index had a marginally positive association with EM (OR: 2.01, 95% CI: 0.98, 4.15), and a significant positive association was identified in subanalysis with participants restricted to premenopausal women (OR: 2.18, 95% CI: 1.03, 4.70). MIBP and MBzP weighted high in model of EM and MEHP weighted the lowest.

CONCLUSION

Comparing results from these three statistical models, the associations between equol, Hg, and MEHP exposure with UL as well as the associations of MIBP, MBzP, and MEHP exposure with EM warrant further research.

Accumulation of distinct persistent organic pollutants is associated with adipose tissue inflammation

Hydrophobic environmental chemicals bio-accumulate in adipose tissue (AT) in animals and humans, but their impact on diseases related to adipose tissue dysfunction remains unclear. Moreover, visceral rather than subcutaneous (SC) fat deposition is more closely associated with cardio-metabolic diseases such as type 2 diabetes, fatty liver and cardiovascular diseases. We therefore tested the hypotheses that environmental chemicals bio-accumulate in a fat depot specific pattern and that these patterns are related AT inflammation and obesity comorbidities. First, we developed an extraction method for detecting and quantifying a set of 9 persistent organic pollutants (POPs) in human AT. The quantified chemicals exhibit K_OW coefficients from 4 to 7. Paired abdominal omental and SC AT samples were obtained from 54 individuals (30 women, 24 men) with a wide range of body mass index (BMI, 16-70 kg/m²) during laparoscopic abdominal surgeries. Among the POPs are classical halogenated substances like Dichlorodiphenyldichloroethylene (DDE) and polychlorinated biphenyls (PCBs), but also fragrance substances. We find that AT concentrations of these chemicals are neither significantly different between visceral and SC fat depots nor between women and men. However, AT bio-accumulation of distinct POPs significantly correlates with AT macrophage infiltration, adipocyte size and parameters of glucose metabolism. In both fat depots, the strongest correlations of POPs (Ethyl- tetradecanoate, 4,4'-Diisopropylbiphenyl, 2-Phenyltetralin, 2,2',4,4',5,5'-Hexachlorobiphenyl, Hexachlorobenzene) and AT macrophage infiltration were detected in lean individuals. In men with obesity, abundance of POPs correlated with the duration of obesity. Additional significant associations between AT POPs and parameters of glycemia, insulin sensitivity, and inflammation suggest that specific environmental chemicals may contribute to AT dysfunction, adipocyte hypertrophy, impaired glucose metabolism, systemic inflammation and variation in fat distribution, but not to obesity.

Environmental chemicals, breast cancer progression and drug resistance

Breast cancer (BC) is one of the most common causes of cancer in the world and the second leading cause of cancer deaths among women. Mortality is associated mainly with the development of metastases. Identification of the mechanisms involved in metastasis formation is, therefore, a major public health issue. Among the proposed risk factors, chemical environment and pollution are increasingly suggested to have an effect on the signaling pathways involved in metastatic tumor cells emergence and progression. The purpose of this article is to summarize current knowledge about the role of environmental chemicals in breast cancer progression, metastasis formation and resistance to chemotherapy. Through a scoping review, we highlight the effects of a wide variety of environmental toxicants, including persistent organic pollutants and endocrine disruptors, on invasion mechanisms and metastatic processes in BC. We identified the epithelial-to-mesenchymal transition and cancer-stemness (the stem cell-like phenotype in tumors), two mechanisms suspected of playing key roles in the development of metastases and linked to chemoresistance, as potential targets of contaminants. We discuss then the recently described pro-migratory and pro-invasive Ah receptor signaling pathway and conclude that his role in BC progression is still controversial. In conclusion, although several pertinent pathways for the effects of xenobiotics have been identified, the mechanisms of actions for multiple other molecules remain to be established. The integral role of xenobiotics in the exposome in BC needs to be further explored through additional relevant epidemiological studies that can be extended to molecular mechanisms.

Influence of polychlorinated biphenyls and organochlorine pesticides on the inflammatory milieu. A systematic review of in vitro, in vivo and epidemiological studies

BACKGROUND

Organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) are relevant families of persistent organic pollutants, which have been linked to several long-term adverse health effects. The mechanisms of action of these pollutants are still poorly understood. However, there are some evidences suggesting that inflammation might play a key role on their effects.

AIM

To systematically synthesize the published in vitro, in vivo and epidemiological data assessing the potential influence of exposure to OCPs and PCBs on the development of an inflammatory milieu.

METHODS

A systematic review of peer-reviewed original research papers published until 1st May 2019 was conducted, by using Medline, Web of Science and Scopus databases. A total of 39 articles met the inclusion criteria and were evaluated in this review.

RESULTS

The majority of the studies showed significant associations of PCB and OCP exposure with all inflammatory markers measured (n = 30). Some studies showed positive and negative associations (n = 7) and only two studies evidenced negative associations (n = 2). Most of the available evidences came from in vitro and in vivo studies (n = 31), with few epidemiological studies (n = 8).

CONCLUSIONS

We found consistent positive associations between exposure to PCBs and OCPs and the development of a pro-inflammatory milieu, with only few discrepancies. However, given the limited epidemiological evidence found, our results warrant further research in order to elucidate the real contribution of these pollutants on the inflammatory processes and subsequent diseases.

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.

First phytochemical study and biological activity of the leaves ethanolic extract from Cissus spinosa Cambess

AIMS: The objective of this study was to identify the phytochemical profile and to evaluate the biological effects of the crude ethanolic extract (EE) and the ethanolic fraction (EF) of leaves of the species Cissus spinosa Cambess, after oxidative stress induced by cyclophosphamide (CP) in mice.METHODS: Phytochemical profile was performed detecting functional groups and, analysis of total flavonoids and phenols concentration, as well as the antiradical activity in EE and EF. The phytochemical characterization was done for the identification of flavonoids present in the leaves of the plant. In the biochemical tests, hematological parameters, glucose and total cholesterol dosages in plasma, enzymatic and non-enzymatic antioxidants and lipid damage marker were evaluated in different tissues (liver, kidney and heart), besides genotoxic and immunological analyzes. The animals received 15 days of treatment, via gavage, with EE (50 mg kg-1) or EF (50 mg kg-1) and on the 15th day, an intraperitoneal injection of CP (100 mg kg-1) or saline (0.9%). After 24 h the last treatment, the animals were anesthetized for blood withdrawal, sacrificed and removal of the organs.RESULTS: In the phytochemical analyzes, the presence of alkaloids, flavonoids and phenols was identified, the latter presented a higher concentration for EF. Eight flavonoids were identified - Rutin, Quercetin-3-β-D-glucoside, Quercitrin, Taxifolin, Quercetin, Canferol, Luteolin and Apigenin. In the biochemical analyzes, in general, EE showed a better antioxidant action against oxidative damages, hypoglycemic and antitilipemic action when comparing with EF, probably due to the synergism caused by flavonoids. It was observed the reduction and an increase of micronucleated polychromatic erythrocytes, due to the action of antioxidant compounds and alkaloids present in the plant, also considering the question of the seasonal period that directly interferes in the production of these compounds. In the immunological analysis, the extracts did not stimulate the spontaneous production of oxygen peroxide (H2O2) and nitric oxide (NO•). CONCLUSIONS: Other studies, such as the variation of the chemical composition of the plant by local seasonality, hypoglycemic and antilipemic action, should be carried out to better delineate the biological action present in this plant.

How polluted is your fat? What the study of adipose tissue can contribute to environmental epidemiology

The study of the potential contribution of low-dose exposure to environmental chemicals on the development of chronic conditions in human populations is often hampered by methodological issues, including exposure misclassification and the inability to assess biological effects in target organs. White adipose tissue (WAT) presents the unique feature of being both an advantageous matrix for assessing long-term exposure to mixtures of persistent organic pollutants and an interesting tissue to investigate early preclinical effects. Moreover, other lipophilic non-persistent chemicals and heavy metals have been recently quantified in fat, suggesting that human WAT contains chemical mixtures more complex than initially thought. However, WAT has been scarcely used in environmental epidemiology due to collection difficulties. In this essay we discuss the potential of using human WAT as a source of both exposure and effect biomarkers, with the aim of advancing the epidemiological research of obesity-related diseases, including metabolic syndrome and cancer. Overall, we discuss the implications of investigating WAT in a multidisciplinary framework combining toxicological and epidemiological knowledge in order to improve the inference of causal relationships in observational settings. We finalise by suggesting feasible designs and scenarios in which WAT samples may be reasonably collected.

Adipose tissue concentrations of non-persistent environmental phenols and local redox balance in adults from Southern Spain

The aim was to evaluate the associations of environmental phenol and paraben concentrations with the oxidative microenvironment in adipose tissue. This study was conducted in a subsample (n = 144) of the GraMo cohort (Southern Spain). Concentrations of 9 phenols and 7 parabens, and levels of oxidative stress biomarkers were quantified in adipose tissue. Associations were estimated using multivariable linear regression analyses adjusted for potential confounders. Benzophenone-3 (BP-3) concentration was borderline associated with enhanced glutathione peroxidase (GPx) activity [exp(β) = 1.20, p = 0.060] and decreased levels of reduced glutathione (GSH) [exp(β) = 0.55, p = 0.070]. Concentrations of bisphenol A (BPA) and methylparaben (MeP) were associated to lower glutathione reductase (GRd) activity [exp(β) = 0.83, exp(β) = 0.72, respectively], and BPA was borderline associated to increased levels of oxidized glutathione (GSSG) [exp(β) = 1.73, p-value = 0.062]. MeP was inversely associated to both hemeoxygenase-1 (HO-1) and superoxide dismustase (SOD) activity, as well as to the levels of thiobarbituric acid reactive substances (TBARS) [0.75 < exp(β) < 0.79]. Our results suggest that some specific non-persistent pollutants may be associated with a disruption of the activity of relevant antioxidant enzymes, in addition to the depletion of the glutathione stock. They might act as a tissue-specific source of free radicals, contributing to the oxidative microenvironment in the adipose tissue.

Associations between persistent organic pollutants and risk of breast cancer metastasis

BACKGROUND

Breast cancer (BC) is a major public health concern with over 2 million new cases diagnosed and over 600,000 deaths in 2018 in women worldwide. When distant metastases are present at diagnosis, the 5-year survival rate is only 26%. Recent studies have suggested that persistent organic pollutants (POPs) that accumulate in adipose tissue (AT) can influence tumor phenotype and stimulate cellular processes important for metastasis such as invasion. We, therefore, tested the hypothesis that POP exposure is associated with BC metastasis.

METHODS

We conducted an exploratory case-control study in which the concentrations of 49 POPs were measured in both AT and serum samples from BC patients, with or without lymph node metastasis, who underwent partial or total mastectomies, lymph node biopsies and sampling of the adipocytic tumor microenvironment. Adjusted, unconditional logistic models were used to study the associations between the POP concentrations and the risk of metastasis and other hallmarks of cancer aggressiveness.

RESULTS

2.3.7.8-TCDD concentrations in AT are positively associated with the risk of metastasis in 43 patients who have BMIs equal or higher than 25 kg/m2 (odds ratio: 4.48 (1.32-20.71)). Furthermore, the concentrations of 2.3.7.8-TCDD and two coplanar PCBs (77&169) in AT also were positively associated with the risk of lymph node metastasis and the tumor size.

CONCLUSION

Our study suggests that 2.3.7.8-TCDD and some PCBs contribute to the development of tumor metastasis and other hallmarks of cancer aggressiveness. While these results should be considered with caution, this is the first study to identify such potential risk factors. Larger longitudinal studies are necessary to confirm our results. Clinical Trial Protocol Record: 2013-A00663-42.

The Cumulative Risk of Chemical and Nonchemical Exposures on Birth Outcomes in Healthy Women: The Fetal Growth Study

Metals, stress, and sociodemographics are commonly studied separately for their effects on birth outcomes, yet often jointly contribute to adverse outcomes. This study analyzes two methods for measuring cumulative risk to understand how maternal chemical and nonchemical stressors may contribute to small for gestational age (SGA). SGA was calculated using sex-specific fetal growth curves for infants of pregnant mothers (n = 2562) enrolled in the National Institute of Child Health and Human Development (NICHD) Fetal Growth Study. The exposures (maternal lead, mercury, cadmium, Cohen's perceived stress, Edinburgh depression scores, race/ethnicity, income, and education) were grouped into three domains: metals, psychosocial stress, and sociodemographics. In Method 1 we created cumulative risk scores using tertiles. Method 2 employed weighted quantile sum (WQS) regression. For each method, logistic models were built with three exposure domains individually and race/ethnicity, adjusting for age, parity, pregnancy weight gain, and marital status. The adjusted effect of overall cumulative risk with three domains, was also modeled using each method. Sociodemographics was the only exposure associated with SGA in unadjusted models ((odds ratio) OR: 1.35, 95% (confidence interval) CI: 1.08, 1.68). The three cumulative variables in adjusted models were not significant individually, but the overall index was associated with SGA (OR: 1.17, 95% CI: 1.02, 1.35). In the WQS model, only the sociodemographics domain was significantly associated with SGA. Sociodemographics tended to be the strongest risk factor for SGA in both risk score and WQS models.

Adverse effects of hexaclorobenzene exposure in children and adolescents

BACKGROUND

Hexachlorobenzene (HCB: C₆Cl₆) is a persistent, bioaccumulative chemical formerly used worldwide in pesticide mixtures but also produced as a by-product in the chemical and metallurgical industry. Despite current international restrictions in the use and production of HCB, the majority of the general population still show detectable levels of HCB, which raises concerns on the potential health implications of the exposure.

OBJECTIVE

To compile and synthesize the available scientific evidence regarding the adverse effects of exposure to HCB in children and adolescents.

METHODS

A review of the literature focused on the adverse effects of HCB exposure in children. Eligible studies were systematically screened from searches in Medline, Scopus and Ebsco-host databases. A total of 62 studies were finally included.

RESULTS AND DISCUSSION

In our search we found evidences of potential health effects linked to HCB exposure at different levels (e.g. neurotoxic, nephrotoxic, immunotoxic, hepatotoxic and toxicogenomic), although the conclusions are still contradictory. Further prospective research is needed, considering the special vulnerability of children and adolescent population as well as the ubiquity of the exposure.

Contribution of sociodemographic, occupational, lifestyle and dietary characteristics to the oxidative stress microenvironment in adipose tissue

The present study was conceived on the basis of the few previous reports suggesting a potential relevance of the oxidative stress microenvironment in the adipose tissue, a biological matrix which is closely related to the development of several chronic pathologies. Thus, our aim was to describe the levels of enzymatic and non-enzymatic antioxidants and markers of oxidative damage in adipose tissue samples from a Spanish cohort, as well as their main sociodemographic, lifestyle, and dietary predictors. The study was conducted in a subsample (n = 271 adults) of GraMo cohort, recruited in Granada (Southern Spain). A face-to-face questionnaire was used to gather data regarding sociodemographic characteristics, lifestyle, dietary habits, health status, and perceived exposure to chemicals. We analyzed adipose tissue levels of lipid peroxidation (TBARS), total superoxide dismutase (SOD) activity, heme oxygenase-1 (HO-1) activity, and glutathione cycle biomarkers. Potential predictors of oxidative stress markers were assessed using stepwise multivariable linear regression analyses. SOD and TBARS levels were mainly related to sociodemographic and occupational characteristics, while the components of the glutathione cycle and HO-1 were predominantly associated with dietary habits. Men showed significantly lower levels of oxidative stress levels than women. In the regression models including only women, the use of oral contraceptive and hormonal therapy was associated with lower levels of oxidative stress, while the number of children was positively associated with increased oxidative biomarkers. Our results suggest that adipose tissue is potentially important matrix for the assessment of oxidative stress, which can be affected by specific environmental factors. These findings might be relevant for public health.

Distribution of Organohalogen and Synthetic Musk Compounds in Breast Adipose Tissue of Breast Cancer Patients in Ulster County, New York, USA

We determined the concentrations of 98 halogenated organic compounds and synthetic musks in breast fat tissues of 50 breast cancer patients (age range: 34-77 years) collected during 1996-1998 in Ulster County, New York, USA. Polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), polybrominated biphenyl 153 (PBB-153), polybrominated diphenyl ethers (PBDEs), and synthetic musk compounds (SMCs) were analyzed in breast fat tissues, and 46 analytes were found at a detection frequency of ≥ 65% and at concentrations in the decreasing order of OCPs > PCBs > SMCs > PBDEs > PBB-153. PCBs (median: 323 ng/g wet wt) and dichlorodiphenyltrichloroethanes (DDTs, median: 293 ng/g wet wt) were the major compounds found in breast fat tissues. Among PCB congeners, hexa- and hepta-chlorobiphenyls (60% of total PCBs) were the abundant ones. p,p'-DDE accounted for more than 99% of the total DDT concentrations. The concentrations of SMCs and PBDEs were 1-2 orders of magnitude lower than those of PCBs and DDTs. 1,3,4,6,7,8-Hexahydro-4,6,6,7,8,8-hexamethylcyclopenta-r-2-benzopyran (median: 33 ng/g wet wt) was the most abundant SMC, whereas BDE-47 (median: 4.5 ng/g wet wt) was the most dominant PBDE congener present in breast tissues. A significant correlation (p < 0.05) between women's age and concentrations of DDTs, chlordanes, hexachlorobenzene and PCBs in breast tissues was found. Concentrations of PCBs, PBDEs, OCPs, and SMCs were not significantly different between malignant and benign tumor cases. This study adds baseline information on target tissue burdens of persistent organic contaminants in breast cancer patients.

Associations of multiple exposures to persistent toxic substances with the risk of hyperuricemia and subclinical uric acid levels in BIOAMBIENT.ES study

Hyperuricemia is becoming a serious public health issue, which is highly influenced by environmental factors, although there is still controversial information on the potential influence of the exposure to Persistent Toxic Substances (PTSs) in the general population. In this study we aimed to assess the association. PTS exposure with uric acid homeostasis in a sample of the Spanish population. Participants were recruited during 2009-2010 in all the main geographical areas of Spain. Exposure to 34 PTSs was estimated by chemical analyses of serum levels of 6 Polychlorinated Biphenyls (PCBs, n = 950), 13 Organochlorine Pesticides (OCPs, n = 453), 6 Perfluoroalkyl Substances (PFAs, n = 755), 7 Polybrominated Diphenyl Ethers (PBDEs, n = 365), urinary Cadmium (n = 926), and Lead in whole blood (n = 882). The two study outcomes were defined as the prevalence of hyperuricemia in the study population and uric acid levels, the latter only in individuals with no previous diagnosis of hyperuricemia. Statistical analyses were performed by means of binomial logistic regression and linear regression, and mixture effects were screened using Weighted Quantile Sum Regression (WQS). Serum concentrations of γ-HCH, o,p´-DDE, PCB-138, PCB-153, PFOA, and urinary Cadmium were associated with an increased risk of hyperuricemia, while PBDE-153 showed an inverse association with the effect. Furthermore, exposure to Cadmium, PCB-138, and to PCB-153 was positively associated with uric acid levels. Results were consistent after lipid adjustment or standardization. WQS analyses revealed a major contribution of PCB-153 within the PCB mixture on both the risk of hyperuricemia and uric acid levels. Sensitivity analyses were performed by adjusting for dietary habits, fasting glucose and estimated glomerular filtration rate. Overall, we found novel associations between human exposure to mixtures of PTSs and disturbances in uric acid homeostasis. However, we cannot completely rule out potential residual confounding effect or reversed-causality related to the cross-sectional design.

Severe nonalcoholic steatohepatitis and type 2 diabetes: liver histology after weight loss therapy in a randomized clinical trial

OBJECTIVE

To evaluate the effectiveness of the fast weight loss method on liver steatosis, fibrosis, inflammation, glycemic and lipid features and body composition in patients with severe nonalcoholic steatohepatitis (NASH) and type 2 diabetes (T2D).

METHODS

A 24 week open prospective randomized controlled clinical trial including 80 adult patients (aged 40-65 years) was performed. The patients after randomization were divided into two groups: the main group followed the fast weight loss method; the control group received conventional drug treatment. The fast weight loss method included calorie restriction, salt intake, walking and sexual self-restraint. The conventional drug therapy included vitamin E, orlistat, pioglitazone hydrochloride, atorvastatin, lisinopril, benzodiazepines and anti-inflammatory agents. Primary endpoints were: ultrasound and histology suggestive of steatohepatitis, hepatic enzymes, weight loss, 2 hour oral glucose tolerance test and glycosylated hemoglobin A1C (HbA1c). Secondary endpoints were: blood pressure and lipids.

RESULTS

A total of 83% patients completed the study. In the main group weight lost was 7-16 kg (10-20% from baseline) for 8-10 weeks. In this group weight was lost due to reduction of fat mass only. The main vs. control group showed higher decrease in fat mass from baseline (p < .001). Ultrasound imaging and liver histological scoring system evidenced significant improvement in liver steatosis/fibrosis in the main group (p < .001). In the main vs. control group weight lost at 24 weeks led to positive laboratory changes in alanine aminotransferase (ALT), aspartate aminotransferase (AST), 2 hour oral glucose tolerance test (OGTT), HbA1c, Homeostasis Model Assessment insulin resistance indexes (HOMA-IR), blood pressure (BP), cholesterol, triglycerides, bilirubin total and blood hemoglobin (p = .01). The fast weight loss in the patients adequately led to decrease in symptomatic drugs up to complete abolition.

CONCLUSIONS

The study showed benefits of the fast weight loss method improving in steatosis/fibrosis and biochemical/metabolic outcomes in patients with severe NASH and T2D.

Environmental phenols and parabens in adipose tissue from hospitalized adults in Southern Spain

Urinary concentrations of non-persistent environmental pollutants (npEPs) are widely assessed in biomonitoring studies under the assumption that they are metabolised and eliminated in urine. However, some of these chemicals are moderately lipophilic, and their presence in other biological matrices should also be evaluated to estimate mid/long-term exposure to npEPs and its impact on human health. The present study aims to explore concentrations and potential determinants of npEPs in adipose tissue from a hospital-based adult cohort (GraMo cohort, Southern Spain). Concentrations of bisphenol-A (BPA), benzophenone-3 (BP-3), triclosan (TCS), three chlorophenols (2,4-DCP, 2,5-DCP and 2,4,5-TCP) and two phenylphenols (2-PP and 4-PP), triclocarban (TCCB) and parabens [methyl- (MeP), ethyl- (EtP), propyl- (n-PrP and i-PrP), butyl- (n-BuP and i-BuP) and benzyl-paraben (BzP)] were analysed in adipose tissue samples from a subcohort of 144 participants. Spearman correlation tests were performed, followed by stepwise multivariable linear regression analyses to assess determinants of the exposure. Detection frequencies and median concentrations were: BPA (86.8%, 0.54 ng/g tissue), BP-3 (79.2%, 0.60 ng/g tissue), TCS (45.8%, <LOD), 2-PP (18.8%, <LOD), MeP (100.0%, 0.40 ng/g tissue), EtP (20.1%, <LOD) and n-PrP (54.2%, 0.06 ng/g tissue). The remaining npEPs were detected in <10% of the samples. BPA, MeP, EtP and n-PrP levels were significantly and positively correlated, while BP-3 showed a positive correlation with TCS and 2-PP. Older participants showed higher concentrations of TCS and MeP, while BMI was inversely associated with most of the analysed compounds and perceived recent weight loss was inversely associated with 2-PP. Female participants and residents of rural areas had increased BP-3 concentrations. npEP concentrations were positively associated with the consumption of fatty food but negatively associated with the consumption of vegetables and fruit. This study reveals the widespread presence of numerous npEPs in adipose tissue from adults in southern Spain, suggesting a generalized distribution of these environmental compounds in fatty tissues. In these adults, many of the determinants of npEP concentrations in adipose tissue were similar to those of more lipophilic and persistent compounds.