Lead-induced hypertension: role of oxidative stress

Environmental pollution and health risks to informal workers: Exposure to heavy metals in human hair at Indonesian landfills

The concentration of heavy metals (HMs) in human hair is a bioindicator of environmental pollution over a long period from worker, including the informal worker at landfills. A landfill is where final-stage refuse is deposited, transported, and disposed of solid waste from urban areas. No study has been conducted on heavy metals in landfills and their health impact on informal workers. This study aims to investigate the accumulation of heavy metals over a long period, the effect of toxic metal exposure on the human body, and the health risks informal workers perceive as bioindicators of pollution in landfills. Human hair samples collected from informal workers and urban were analyzed by inductively coupled plasma mass spectrometry (ICP-MS) to measure HMs and human hair certified reference material (CRM) from the national institute for environmental studies, Japan. The sample consisted of individuals who were interviewed and had their hair cut. The total number of respondents in this study was 51 people. The average concentrations of the element heavy metals (µg/g) in informal workers are shown: Pb 4.70, As 0.30, Cd 1.07, Mn 14.58, Co 0.14, Cu 19.31, Fe 73.05, Zn 646.2, and Se 0.65. The results of our study the concentrations of heavy metals were higher than those found for urban residents. In the education level variable, 17.4 % of respondents did not attend school, 50 % attended primary school, and 32.6 % attended junior high school. Gender of respondents, 71.7 % are female, and in the working period, 69.6 % are more than ten years old. An epidemiological study and statistical analysis show the respondents' symptoms & health complaints such as cough, breathlessness, headache, nose irritation, variable mask, duration using a mask, and characteristics of the respondent's significant correlations p-value < 0.05 with a concentration of all metals. These findings show that the HMs have contaminated the environment and entered the human bodies, posing health risks to informal workers in the landfill working area.

Characteristics of genomic alterations and heavy metals in hypertensive patients with non‑small cell lung cancer

Both lung cancer and cardiovascular disease (CVD) are prevalent diseases that contribute to global mortality rates. Although individuals with CVD may face an elevated risk of cancer based on the presence of shared risk factors (such as tobacco smoking and excessive body weight), the roles of somatic mutations and heavy metal distributions remain unknown. The present study aimed to explore the differences in somatic mutations and heavy metal distributions between hypertensive patients and non-hypertensive patients in a cohort of patients with non-small cell lung cancer (NSCLC). Tumor tissue samples from 64 patients were analyzed using a next-generation sequencing panel consisting of 82 tumor-related genes through hybrid capture. Serum samples were also analyzed to determine the levels of 18 heavy metals using inductively-coupled plasma mass spectrometry. Among the 16 hypertensive patients, all patients (16/16; 100.00%) harbored 47 somatic mutations in 14 mutant genes, whereas 45 patients without hypertension (45/48; 93.75%) harbored 113 somatic mutations across 26 mutant genes (no mutations were detected in the remaining 3 patients). Among the 32 identified mutant genes in these two groups, FBXW7, CBR3, CDKN2A, HRAS, SMO and UGT1A1 were exclusively observed in patients with hypertension, while 18 mutant genes were only observed in patients without hypertension. No significant mutually exclusive interactions were found in hypertensive patients, but mutually exclusive interactions were observed between EGFR and STK11 (P=0.0240) and between STK11 and KRAS (P=0.0169) in non-hypertensive patients. 'Non-small cell lung cancer' was the top Kyoto Encyclopedia of Genes and Genomes pathway in hypertensive patients, whereas 'central carbon metabolism in cancer' was the top pathway in patients without hypertension. Moreover, the proportions of altered key signaling pathways and biological function categories shared between these two groups were 54.37% (56/103) and 21.62% (8/37), respectively. Furthermore, the levels of chromium (Cr) in the serum of hypertensive patients were notably elevated compared with those in patients without hypertension. In addition, significant negative correlations were observed between Cr and CEA, between CYFRA21-1 and Zn, and between NSE and As in hypertensive patients but not in non-hypertensive patients, indicating differing interactive profiles among the traditional serum biomarkers and heavy metals between these two patient groups. In summary, there were differences in genomic alterations, somatic interactions and the serum levels of Cr between patients with NSCLC with hypertension and patients with NSCLC without hypertension. Furthermore, patients with hypertension exhibited significant negative correlations between Cr and CEA, between CYFRA21-1 and Zn, and between NSE and As, suggesting that heavy metals may contribute to the occurrence of NSCLC with different hypertensive status.

Silibinin-loaded Nanostructured Lipid Carriers (NLCs) Ameliorated Lead-induced Acute Nephrotoxicity in Male Rats

As a toxic heavy metal, lead (Pb) is well known for impairment of renal function due to oxidative injuries. In contrast, the antioxidant activity of silibinin has been approved. Given the role of silibinin antioxidant activity, the present study investigated the effectiveness of silibinin-loaded nanostructured lipid carriers (Sili-NLCs) against Pb-induced acute nephrotoxicity in rats. The emulsification-solvent evaporation method was applied to prepare Sili-NLCs. Sixty male Wistar rats were divided into ten separate groups. Pb (20 mg/kg/day, i.p.) was applied to induce nephrotoxicity and in the treatment groups animals received the same concentration of silibinin and Sili-NLCs (25, 50, and 100 mg/kg/day, p.o.) for five days. After sacrificing rats, kidney tissue samples were collected to assess the oxidative stress parameters, including lipid peroxidation (LPO), nitric oxide (NO), superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) activity. Also, histopathological examination using Hematoxylin-Eosin (H&E) was studied. Not only did Pb injection significantly increase the renal levels of LPO and NO, but also decreased the levels of antioxidant enzyme activity. On the other hand, Sili-NLCs were more effective than silibinin in decreasing renal oxidative damage by increasing the antioxidant defense system. Moreover, the histopathological examination correlated well with biochemical findings. Our data suggested that Sili-NLCs are potentially superior to pure silibinin for attenuating Pb-induced acute nephrotoxicity.

Determination of heavy metals and risk assessment in nail cosmetics sold in Seoul, Korea

OBJECTIVE

The objective of this study was to evaluate some toxic levels of nail cosmetics marketed in Seoul, Korea and health risk assessment on humans.

METHODS

We collected 45 random nail cosmetics and analysed for lead, cadmium, arsenic and antimony by inductively coupled plasma-optical emission spectrometry (ICP-OES).

RESULTS

Four metals concentrations were Pb 0.037 ± 0.083 (

DISCUSSION AND CONCLUSION

Six nail cosmetics had high antimony concentrations which were higher than the current legal limit in Korea. Because of 6 high antimony concentrations, MoS, HQ and HI were outside the acceptable range. LCR value for Pb, As and Cd was below 1 0 -6 which was lower than the permissible limit and nail cosmetics may not possess lifetime cancer risk. Our results suggested that metals were present in nail cosmetics at diverse concentrations and some nail cosmetics appeared to pose a harmful impact on health.

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Key Words

• ICP-OES
• Nail cosmetics
• Seoul
• health risk assessment
• heavy metals

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MESH Headings

• Humans
• Cadmium/toxicity
• Cadmium/analysis
• Antimony/analysis
• Seoul
• Lead/toxicity
• Metals, Heavy/toxicity
• Metals, Heavy/analysis
• Cosmetics/analysis
• Risk Assessment

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Affiliation(s)

Suun Kim Food & Drug Division, Seoul Metropolitan Government Research Institute of Public Health and Environment, Seoul, Korea
Chaeman Choi Food & Drug Division, Seoul Metropolitan Government Research Institute of Public Health and Environment, Seoul, Korea
Myeongsook Lee Food & Drug Division, Seoul Metropolitan Government Research Institute of Public Health and Environment, Seoul, Korea
Insook Hwang Food & Drug Division, Seoul Metropolitan Government Research Institute of Public Health and Environment, Seoul, Korea

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Lead poisoning with unusual manifestations in an opium-addicted man

One of the contributing causes of hypertension or exacerbation of ischemic heart disease (IHD) has been suggested to be environmental pollution and occupational exposure to particular metals, such as lead. Here, we describe a 43-year-old man with a history of oral opium with symptoms of IHD due to chest pain.

Overview of the cardiovascular effects of environmental metals: New preclinical and clinical insights

Environmental causes of cardiovascular diseases (CVDs) are global health issues. In particular, an association between metal exposure and CVDs has become evident but causal evidence still lacks. Therefore, this symposium at the Society of Toxicology 2022 annual meeting addressed epidemiological, clinical, pre-clinical animal model-derived and mechanism-based evidence by five presentations: 1) An epidemiologic study on potential CVD risks of individuals exposed occupationally and environmentally to heavy metals; 2) Both presentations of the second and third were clinical studies focusing on the potential link between heavy metals and pulmonary arterial hypertension (PAH), by presenting altered blood metal concentrations of both non-essential and essential metals in the patients with PAH and potential therapeutic approaches; 3) Arsenic-induced atherosclerosis via inflammatory cells in mouse model; 4) Pathogenic effects on the heart by adult chronic exposure to very low-dose cadmium via epigenetic mechanisms and whole life exposure to low dose cadmium via exacerbating high-fat-diet-lipotoxicity. This symposium has brought epidemiologists, therapeutic industry, physicians, and translational scientists together to discuss the health risks of occupational and environmental exposure to heavy metals through direct cardiotoxicity and indirect disruption of homeostatic mechanisms regulating essential metals, as well as lipid levels. The data summarized by the presenters infers a potential causal link between multiple metals and CVDs and defines differences and commonalities. Therefore, summary of these presentations may accelerate the development of efficient preventive and therapeutic strategies by facilitating collaborations among multidisciplinary investigators.

Misuse of Cardiac Lipid upon Exposure to Toxic Trace Elements-A Focused Review

Heavy metals and metalloids like cadmium, arsenic, mercury, and lead are frequently found in the soil, water, food, and atmosphere; trace amounts can cause serious health issues to the human organism. These toxic trace elements (TTE) affect almost all the organs, mainly the heart, kidney, liver, lungs, and the nervous system, through increased free radical formation, DNA damage, lipid peroxidation, and protein sulfhydryl depletion. This work aims to advance our understanding of the mechanisms behind lipid accumulation via increased free fatty acid levels in circulation due to TTEs. The increased lipid level in the myocardium worsens the heart function. This dysregulation of the lipid metabolism leads to damage in the structure of the myocardium, inclusive fibrosis in cardiac tissue, myocyte apoptosis, and decreased contractility due to mitochondrial dysfunction. Additionally, it is discussed herein how exposure to cadmium decreases the heart rate, contractile tension, the conductivity of the atrioventricular node, and coronary flow rate. Arsenic may induce atherosclerosis by increasing platelet aggregation and reducing fibrinolysis, as exposure interferes with apolipoprotein (Apo) levels, resulting in the rise of the Apo-B/Apo-A1 ratio and an elevated risk of acute cardiovascular events. Concerning mercury and lead, these toxicants can cause hypertension, myocardial infarction, and carotid atherosclerosis, in association with the generation of free radicals and oxidative stress. This review offers a complete overview of the critical factors and biomarkers of lipid and TTE-induced cardiotoxicity useful for developing future protective interventions.

Interactive effects of high temperature and pesticide exposure on oxidative status, apoptosis, and renin expression in kidney of goldfish: Molecular and cellular mechanisms of widespread kidney damage and renin attenuation

One of many noteworthy consequences of increasing societal reliance on pesticides is their predominance in aquatic environments. These pernicious chemicals interact with high temperatures from global climate change, heat waves, and natural variations to create unstable environments that negatively impact organisms' health. To understand these conditions, we examined the dose-dependent effects of environmentally relevant pesticide mixtures (metolachlor, linuron, isoproturon, tebuconazole, aclonifen, atrazine, pendimethalin, and azinphos-methyl) combined with elevated temperatures (22 control vs. 32°C for 4-week exposure) on renin, dinitrophenyl protein (DNP, an indicator of reactive oxygen species, ROS), 3-nitrotyrosine protein (NTP, an indicator of reactive nitrogen species, RNS), superoxidase dismutase (SOD, an antioxidant), and catalase (CAT, an antioxidant) expressions in the kidneys of goldfish (Carassius auratus). Histopathological analysis showed widespread damage to kidney tissues in high temperature and pesticide co-exposure groups, including rupture of the epithelial layer, hemorrhaging, and degeneration of tubular epithelium. Quantitative real-time polymerase chain reaction (qRT-PCR) and immunohistochemical analyses demonstrated significant declines in renin receptor-like mRNA and protein expressions in kidney tissues under combined exposure to high temperature and pesticides compared with controls; conversely, expression of DNP, NTP, SOD, and CAT increased in kidney tissues under the same conditions. Apoptotic cells were also increased in co-exposure groups as assessed by in situ terminal deoxynucleotidyl transferase dUTP nick labeling (TUNEL) assay. The enhanced apoptosis in kidneys of heat and pesticides co-exposed fish was associated with increased caspase-3 (a protease enzyme) mRNA levels. Our results demonstrated that high temperature and pesticides induced oxidative/nitrative stress (i.e., ROS/RNS), damaged tissues, increased cellular apoptosis, and suppressed renin expression in kidneys of goldfish.

Role of environmental toxicants in the development of hypertensive and cardiovascular diseases

The incidence of hypertension with diabetes mellitus (DM) as a co-morbid condition is on the rise worldwide. In 2000, an estimated 972 million adults had hypertension, which is predicted to grow to 1.56 billion by 2025. Hypertension often leads to diabetes mellitus that strongly puts the patients at an increased risk of cardiovascular, kidney, and/or atherosclerotic diseases. Hypertension has been identified as a major risk factor for the development of diabetes; patients with hypertension are at two-to-three-fold higher risk of developing diabetes than patients with normal blood pressure (BP). Causes for the increase in hypertension and diabetes are not well understood, environmental factors (e.g., exposure to environmental toxicants like heavy metals, organic solvents, pesticides, alcohol, and urban lifestyle) have been postulated as one of the reasons contributing to hypertension and cardiovascular diseases (CVD). The mechanism of action(s) of these toxicants in developing hypertension and CVDs is not well defined. Research studies have linked hypertension with the chronic consumption of alcohol and exposure to metals like lead, mercury, and arsenic have also been linked to hypertension and CVD. Workers chronically exposed to styrene have a higher incidence of CVD. Recent studies have demonstrated that exposure to particulate matter (PM) in diesel exhaust and urban air contributes to increased CVD and mortality. In this review, we have imparted the role of environmental toxicants such as heavy metals, organic pollutants, PM, alcohol, and some drugs in hypertension and CVD along with possible mechanisms and limitations in extrapolating animal data to humans.

The Associations between Blood and Urinary Concentrations of Metal Metabolites, Obesity, Hypertension, Type 2 Diabetes, and Dyslipidemia among US Adults: NHANES 1999-2016

Background

Heavy metals are well known to be associated with cancer outcomes, but its association with obesity and cardiometabolic risk outcomes requires further study.

Methods

Adult data from the National Health and Examination Survey (NHANES Continuous 1999-2016, n = 12,636 to 32,012) with data for blood or urinary metals concentrations and body mass index were used. The study aim was twofold: (1) to determine the association between heavy metals and obesity and (2) to examine the influence of heavy metals on the relationship between obesity and hypertension, type 2 diabetes, and dyslipidemia. Logistic regression was used to examine the main effects and interaction effects of metals and obesity for the odds of prevalent hypertension, type 2 diabetes, and dyslipidemia. Models were adjusted for age, gender, ethnicity, smoking status, physical active status, and poverty-income ratio, with additional adjustment for creatinine in models with the urinary measures of heavy metals. High-low concentration categories were defined by grouping metal quintiles with the most similar associations with obesity.

Results

Blood lead had a negative linear association with obesity (odds ratio (OR)  = 0.42, 95% confidence interval (CI) = 0.37-0.47). In those with obesity, high blood lead was associated with lower risk of prevalent dyslipidemia, while no association was found in those without obesity. The study observed a curvilinear relationship between urinary antimony and obesity with the moderate group having the highest odds of obesity (OR = 1.36, 1.16-1.59). However, the relationship between urinary antimony and prevalent hypertension and dyslipidemia risk was linear, positive, and independent of obesity. While not associated with prevalent obesity risk, high urinary uranium was associated with 30% (P=0.01) higher odds for prevalent type 2 diabetes.

Conclusions

The impact of environmental factors on obesity and health may be complex, and this study reinforces the heterogeneous relationship between various metals, obesity, and obesity-related metabolic diseases even at levels observed in the general population.

Prenatal blood lead levels and reduced preadolescent glomerular filtration rate: Modification by body mass index

BACKGROUND

For the developing kidney, the prenatal period may represent a critical window of vulnerability to environmental insults resulting in permanent nephron loss. Given that the majority of nephron formation is complete in the 3rd trimester, we set out to test whether 1) prenatal lead exposure is associated with decreased preadolescent kidney function and 2) whether preadolescent obesity acts synergistically with early life lead exposure to reduce kidney function.

METHODS

Our study included 453 mother-child pairs participating in the PROGRESS birth cohort. We assessed prenatal blood lead levels (BLLs) in samples collected in the 2nd and 3rd trimesters and at delivery, as well as tibial and patellar bone lead measures assessed one-month postpartum. Preadolescent estimated glomerular filtration rate (eGFR) was derived from serum levels of creatinine and/or cystatin C measured at age 8-12 years. We applied linear regression to assess the relationship between prenatal bone and BLL with preadolescent eGFR, and adjusted for covariates including age, sex, BMI z-score, indoor tobacco smoke exposure, and socioeconomic status. We also examined sex-specific associations and tested for effect modification by BMI status.

RESULTS

We observed null associations between prenatal lead exposure and eGFR. However, in interaction analyses we found that among overweight children, there was an inverse association between BLL (assessed at 2nd and 3rd trimester and at delivery) and preadolescent eGFR. For example, among overweight participants, a one ln-unit increase in 2nd trimester BLL was associated with a 10.5 unit decrease in cystatin C-based eGFR (95% CI: -18.1, -2.8; p = 0.008). Regardless of lead exposure, we also observed null relationships between BMI z-score and eGFR overall, as well as among overweight participants. However, among participants with preadolescent obesity, we observed a significant 5.9-unit decrease in eGFR. We observed no evidence of sex-specific effects.

CONCLUSIONS

Our findings, if confirmed in other studies, suggest a complex interplay between the combined adverse effects of adiposity and perinatal lead exposure as they relate to adolescent kidney function. Future studies will assess kidney function and adiposity trajectories through adolescence to better understand environmental risk factors for kidney function decline.

Blood Lead, Systemic Inflammation, and Blood Pressure: Exploring Associations and Mediation Effects in Workers Exposed to Lead

Relationships of lead exposure with blood pressure and blood lead with inflammation have been previously established yet, but the conclusions are still controversial. The objective of our study was to investigate the role of systemic inflammation in the relationships between blood lead concentration and blood pressure. We quantified the levels of blood lead and white blood cell count in 505 lead-exposed workers with 842 observations. Associations between blood lead, white blood cell count, and blood pressure were evaluated by using linear mixed models. We further performed mediation analysis to investigate the role of white blood cell count in the associations between blood lead concentration and blood pressure. We observed that each 1% increase of blood lead levels was significantly positively associated with a 0.9%, 1.7%, and 1.1% increases in systolic blood pressure, white blood cell count, and blood platelet count, respectively. Also, we found that the levels of white blood cell count were positively correlated with diastolic blood pressure and systolic blood pressure in a dose-response manner. Mediation analysis showed that the levels of white blood cell significantly mediated the associations between concentration of blood lead and systolic blood pressure. Collectively, our findings suggest that blood lead was positively associated with systolic blood pressure and that systemic inflammation might play a key role in this association.

Childhood Lead Exposure and Adult Neurodegenerative Disease

Millions of Americans now entering midlife and old age were exposed to high levels of lead, a neurotoxin, as children. Evidence from animal-model and human observational studies suggest that childhood lead exposure may raise the risk of adult neurodegenerative disease, particularly dementia, through a variety of possible mechanisms including epigenetic modification, delayed cardiovascular and kidney disease, direct degenerative CNS injury from lead remobilized from bone, and lowered neural and cognitive reserve. Within the next ten years, the generation of children with the highest historical lead exposures, those born in the 1960s, 1970s, and 1980s, will begin to enter the age at which dementia symptoms tend to emerge. Many will also enter the age in which lead stored in the skeleton may be remobilized at greater rates, particularly for women entering menopause and men and women experiencing osteoporosis. Should childhood lead exposure prove pro-degenerative, the next twenty years will provide the last opportunities for possible early intervention to forestall greater degenerative disease burden across the aging lead-exposed population. More evidence is needed now to characterize the nature and magnitude of the degenerative risks facing adults exposed to lead as children and to identify interventions to limit long-term harm.

Effects of Humic Acids in Chronic Lead Poisoning

Chronic exposure to lead causes disruption to energy production mechanisms and tissue damage, in particular through its binding to thiol groups and competition for zinc binding sites. We investigated the possibility of preventing the consequences of chronic lead poisoning by administration of three different doses of humic acids (HAs) into feed with the aim of establishing an effective HA dose. During the 10-week experiment, a sub-lethal dose of lead acetate was given to rats during the first 5 weeks, with continuous administration of HA over 10 weeks. Measurements were taken to determine the content of the metals Pb, Mn, Cu, Fe and Zn; the metalloid Se; and selected antioxidant markers in the heart, liver, kidney and plasma after the first, fifth and tenth weeks of experiment. The administration of lead and HAs clearly affects the redistribution of the elements and the activity of the antioxidant enzymes. This fact was particularly highlighted in the lead-only group as, within the experiment, significantly higher Pb concentrations were found only in the plasma of this group. However, in the group with 1% HA administered with lead, we observed a rise in Zn concentrations in the organs and the deposition of Fe into the liver. Decreased glutathione reductase activity in the plasma and balanced reduced glutathione concentrations indicated sufficient efficiency of redox reactions. SOD activities were among those affected most strongly, with only the 1% HA group showing no effect on heavy metal redistribution as a result of HA administration.

Associations between prenatal lead exposure and birth outcomes: Modification by sex and GSTM1/GSTT1 polymorphism

Maternal lead exposure is associated with poor birth outcomes. However, modifying effects of polymorphism in glutathione S-transferases (GST) gene and infant sex remain unexplored. Our aim was to evaluate whether associations between prenatal lead and birth outcomes differed by maternal GST genes and infant sex. Prospective data of 782 mother-child pairs from Mothers and Children's Environmental Health (MOCEH) study were used. The genotyping of GST-mu 1 (GSTM1) and theta-1 (GSTT1) polymorphisms was carried out using polymerase chain reaction. Multivariable linear regression was used to examine whether the association between blood lead (BPb) level and birth outcomes (birthweight, length, and head circumference) varied by maternal GST genes and sex. We did not find a statistically significant association between prenatal BPb levels and birth outcomes; in stratified analyses, the association between higher BPb level during early pregnancy and lower birthweight (β=-224 per square root increase in BPb; 95% confidence interval (CI): -426, -21; false discovery rate p=0.036) was significant in males of mothers with GSTM1 null. Results were similar for head circumference model (β=-0.78 per square root increase in BPb; 95% CI: -1.69, 0.14, p=0.095), but the level of significance was borderline. Head circumference model showed a significant three-way interaction among BPb during early pregnancy, GSTM1, and sex (p=0.046). For combined analysis with GSTM1 and GSTT1, GSTM1 null and GSTT1 present group showed a significant inverse association of BPb with birthweight and head circumference in males. Our findings of the most evident effects of BPb on the reduced birthweight and head circumference in male born to the mother with GSTM1 null may suggest a biological interaction among lead, GST genes and sex in detoxification process during fetal development.

The association between cadmium and lead exposure and blood pressure among workers of a smelting industry: a cross-sectional study

BACKGROUND

Lead and cadmium are harmful heavy metals that are used for a variety of occupational purposes. Considering their potentially hazardous effects on health, studies on the association between exposure to these two heavy metals and health disorders have been actively conducted. This study aimed to determine the association between blood lead and cadmium levels and blood pressure in workers exposed to lead and cadmium in a smelter.

METHODS

Nine hundred and sixty-three male workers who worked in a smelter, and underwent medical examinations at the Ulsan University Hospital between January 1 and December 31, 2014, were selected as participants. Among them, 310 subjects whose data on height, weight, blood pressure, fasting blood glucose, lipid profile, and blood lead and cadmium levels were available and who answered the questionnaire were selected as the final participants. We investigated the drinking habit, smoking status, exercise adequacy, and family history of hypertension of these workers using formal questionnaires. A statistical analysis was conducted using Student's t-test, analysis of variance, and linear or logistic regression.

RESULTS

The association between blood lead and cadmium levels and blood pressure was analyzed through statistical adjustment of the risk factors of hypertension. Results showed an association between blood cadmium level and blood pressure elevation. However, blood lead level was found to be not correlated with blood pressure elevation.

CONCLUSIONS

This study shows the association between blood cadmium level and systolic blood pressure (SBP) and diastolic blood pressure (DBP) elevation.

TRIAL REGISTRATION

IRB No. 2017-03-037. Retrospectively Registered 30 March 2017.

Lack of Reactive Oxygen Species Deteriorates Blood Pressure Regulation in Acute Stress

This study investigated the contribution of reactive oxygen species (ROS) to blood pressure regulation in conscious adult male Wistar rats exposed to acute stress. Role of ROS was investigated in rats with temporally impaired principal blood pressure regulation systems using ganglionic blocker pentolinium (P, 5 mg/kg), angiotensin converting enzyme inhibitor captopril (C, 10 mg/kg), nitric oxide synthase inhibitor L-NAME (L, 30 mg/kg) and superoxide dismutase mimeticum tempol (T, 25 mg/kg). Mean arterial pressure (MAP) was measured by the carotid artery catheter and inhibitors were administered intravenously. MAP was disturbed by a 3-s air jet, which increased MAP by 35.2±3.0 % vs. basal MAP after the first exposure. Air jet increased MAP in captopril- and tempol-treated rats similarly as observed in saline-treated rats. In pentolinium-treated rats stress significantly decreased MAP vs. pre-stress value. In L-NAME-treated rats stress failed to affect MAP significantly. Treatment of rats with P+L+C resulted in stress-induced MAP decrease by 17.3±1.3 % vs. pre-stress value and settling time (20.1±4.2 s). In P+L+C+T-treated rats stress led to maximal MAP decrease by 26.4±2.2 % (p<0.005 vs. P+L+C) and prolongation of settling time to 32.6±3.3 s (p<0.05 vs. P+L+C). Area under the MAP curve was significantly smaller in P+L+C-treated rats compared to P+L+C+T-treated ones (167±43 vs. 433±69 a.u., p<0.008). In conclusion, in rats with temporally impaired blood pressure regulation, the lack of ROS resulted in greater stress-induced MAP alterations and prolongation of time required to reach new post-stress steady state.

The detrimental effects of lead on human and animal health

Lead, a chemical element in the carbon group with symbol Pb (from Latin: Plumbum, meaning “the liquid silver”) and has an atomic number 82 in the periodic table. It was the first element that was characterized by its kind of toxicity. In animal systems, lead (Pb) has been incriminated in a wide spectrum of toxic effects and it is considered one of the persistent ubiquitous heavy metals. Being exposed to this metal could lead to the change of testicular functions in human beings as well as in the wildlife. The lead poising is a real threat to the public health, especially in the developing countries. Accordingly, great efforts on the part of the occupational and public health have been taken to curb the dangers of this metal. Hematopoietic, renal, reproductive, and central nervous system are among the parts of the human body and systems that are vulnerable toward the dangers following exposure to high level of Pb. In this review, we discussed the massive harmful impact that leads acetate toxicity has on the animals and the worrying fact that this harmful toxicant can be found quite easily in the environment and abundance. Highlighting its (Pb) effects on various organs in the biological systems, its economic, as well as scientific importance, with the view to educate the public/professionals who work in this area. In this study, we focus on the current studies and research related to lead toxicity in animals and also to a certain extent toward human as well.

Salivary Alterations in Rats with Experimental Chronic Kidney Disease

Objective

This study aimed to analyze changes in saliva composition and salivary secretion process of rats with chronic kidney disease induced by 5/6 nephrectomy to set the foundation for salivary studies related to CKD.

Methods

CKD was induced in Wistar rats via 5/6 nephrectomy. Blood and saliva samples were collected from Control, Sham and CKD groups at 8 and 12 weeks after the surgery. Salivation was stimulated via intraperitoneal injections of pilocarpine (1.0 mg/Kg body weight) or isoproterenol (5.0 mg/Kg body weight). Saliva was collected and immediately stored at -80°C until analysis. The salivary flow rate, total protein, amylase and peroxidase activities, and urea concentrations were measured. The blood urea nitrogen (BUN) and serum creatinine concentrations were also evaluated.

Results

Increases in BUN and serum creatinine concentrations were observed in the CKD groups. Amylase activity was significantly reduced in response to both stimuli in the CKD groups at 8 weeks and increased in the CKD groups at 12 weeks in response to isoproterenol stimulus. The peroxidase activities of the CKD groups were significantly reduced in response to isoproterenol stimulation and were increased at 12 weeks in response to pilocarpine stimulation. Salivary urea was significantly increased in the CKD groups at 8 weeks in response to the isoproterenol stimuli and at 12 weeks in response to both salivary agonists.

Conclusions

The pattern of alterations observed in this experimental model is similar to those observed in patients and clearly demonstrates the viability of 5/6 nephrectomy as an experimental model in future studies to understand the alterations in salivary compositions and in salivary glands that are elicited by CKD.

Maternal exposure to neighborhood soil Pb and eclampsia risk in New Orleans, Louisiana (USA): evidence from a natural experiment in flooding

BACKGROUND

Previous studies link maternal blood lead (Pb) levels and pregnancy-related hypertensive disorders.

OBJECTIVE

Assess the relationship between neighborhood soil Pb and maternal eclampsia risk.

METHODS

Zip code summarized high density soil survey data of New Orleans collected before and after Hurricanes Katrina and Rita (HKR) were merged with pregnancy outcome data on 75,501 mothers from the Louisiana office of public health. Cross-sectional logistic regression analyses are performed testing the association between pre-HKR accumulation of Pb in soils in thirty-two neighborhoods and eclampsia risk. Then we examine whether measured declines in soil Pb following the flooding of the city resulted in corresponding reductions of eclampsia risk.

RESULTS

Cross-sectional analyses show that a one standard deviation increase in soil Pb increases the odds of eclampsia by a factor of 1.48 (95% CI: 1.31, 1.66). Mothers in zip code areas with soil Pb>333 mg/kg were 4.00 (95% CI: 3.00, 5.35) times more likely to experience eclampsia than mothers residing in neighborhoods with soil Pb<50mg/kg. Difference-in-differences analyses capturing the exogenous reduction in soil Pb following the 2005 flooding of New Orleans indicate that mothers residing in zip codes experiencing decrease in soil Pb (-387.9 to -33.6 mg/kg) experienced a significant decline in eclampsia risk (OR=0.619; 95% CI: 0.397, 0.963).

CONCLUSIONS

Mothers residing in neighborhoods with high accumulation of Pb in soils are at heightened risk of experiencing eclampsia.

Endothelial dysfunction in experimental models of arterial hypertension: cause or consequence?

Hypertension is a risk factor for other cardiovascular diseases and endothelial dysfunction was found in humans as well as in various commonly employed animal experimental models of arterial hypertension. Data from the literature indicate that, in general, endothelial dysfunction would not be the cause of experimental hypertension and may rather be secondary, that is, resulting from high blood pressure (BP). The initial mechanism of endothelial dysfunction itself may be associated with a lack of endothelium-derived relaxing factors (mainly nitric oxide) and/or accentuation of various endothelium-derived constricting factors. The involvement and role of endothelium-derived factors in the development of endothelial dysfunction in individual experimental models of hypertension may vary, depending on the triggering stimulus, strain, age, and vascular bed investigated. This brief review was focused on the participation of endothelial dysfunction, individual endothelium-derived factors, and their mechanisms of action in the development of high BP in the most frequently used rodent experimental models of arterial hypertension, including nitric oxide deficient models, spontaneous (pre)hypertension, stress-induced hypertension, and selected pharmacological and diet-induced models.

Endothelial dysfunction in experimental models of arterial hypertension: cause or consequence?

Hypertension is a risk factor for other cardiovascular diseases and endothelial dysfunction was found in humans as well as in various commonly employed animal experimental models of arterial hypertension. Data from the literature indicate that, in general, endothelial dysfunction would not be the cause of experimental hypertension and may rather be secondary, that is, resulting from high blood pressure (BP). The initial mechanism of endothelial dysfunction itself may be associated with a lack of endothelium-derived relaxing factors (mainly nitric oxide) and/or accentuation of various endothelium-derived constricting factors. The involvement and role of endothelium-derived factors in the development of endothelial dysfunction in individual experimental models of hypertension may vary, depending on the triggering stimulus, strain, age, and vascular bed investigated. This brief review was focused on the participation of endothelial dysfunction, individual endothelium-derived factors, and their mechanisms of action in the development of high BP in the most frequently used rodent experimental models of arterial hypertension, including nitric oxide deficient models, spontaneous (pre)hypertension, stress-induced hypertension, and selected pharmacological and diet-induced models.

Lead poisoning-induced hypertensive crisis managed by prazosin: a case report

Introduction

Chronic lead exposure is known to be a risk factor for hypertension (HTN). No specific medication is recommended for the treatment of lead-induced hypertension (LIHTN).

Case Presentation

Our patient was a male admitted with the chief complaint of chronic abdominal pain. His whole blood lead level was reported to be 1961 µg/L. He also mentioned a previous history of HTN managed by propranolol (10 mg, TDS). He discharged himself by giving written consent and 19 days later, he was re-admitted due to high blood pressure of 220/140 mmHg. His Blood pressure (BP) was decreased to 180/110 mmHg with sublingual captopril; but, in maintenance therapy, higher doses of captopril could not further decrease BP. Amlodipine was tried which was discontinued due to the patient intolerance. Prazosin was then administered in gradual increasing doses up to 1 mg twice a day and captopril was tapered.

Conclusions

We would like to suggest that LIHTN may better be managed by alpha blockers compared with converting enzyme inhibitors

Analysis of lead toxicity in human cells

BACKGROUND

Lead is a metal with many recognized adverse health side effects, and yet the molecular processes underlying lead toxicity are still poorly understood. Quantifying the injurious effects of lead is also difficult because of the diagnostic limitations that exist when analyzing human blood and urine specimens for lead toxicity.

RESULTS

We analyzed the deleterious impact of lead on human cells by measuring its effects on cytokine production and gene expression in peripheral blood mononuclear cells. Lead activates the secretion of the chemokine IL-8 and impacts mitogen-dependent activation by increasing the secretion of the proinflammatory cytokines IL-6 and TNF-α and of the chemokines IL-8 and MIP1-α in the presence of phytohemagglutinin. The recorded changes in gene expression affected major cellular functions, including metallothionein expression, and the expression of cellular metabolic enzymes and protein kinase activity. The expression of 31 genes remained elevated after the removal of lead from the testing medium thereby allowing for the measurement of adverse health effects of lead poisoning. These included thirteen metallothionein transcripts, three endothelial receptor B transcripts and a number of transcripts which encode cellular metabolic enzymes. Cellular responses to lead correlated with blood lead levels and were significantly altered in individuals with higher lead content resultantly affecting the nervous system, the negative regulation of transcription and the induction of apoptosis. In addition, we identified changes in gene expression in individuals with elevated zinc protoporphyrin blood levels and found that genes regulating the transmission of nerve impulses were affected in these individuals. The affected pathways were G-protein mediated signaling, gap junction signaling, synaptic long-term potentiation, neuropathic pain signaling as well as CREB signaling in neurons. Cellular responses to lead were altered in subjects with high zinc protoporphyrin blood levels.

CONCLUSIONS

The results of our study defined specific changes in gene and protein expression in response to lead challenges and determined the injurious effects of exposures to lead on a cellular level. This information can be used for documenting the health effects of exposures to lead which will facilitate identifying and monitoring efficacious treatments for lead-related maladies.

Lead induces dysregulation of iron regulatory protein 1 via the extracellular signal-regulated kinase pathway in human vascular endothelial cells

Lead (Pb) can target the vascular system for both acute injury and disease promotion. Cellular iron (Fe) disruption may be implicated in Pb vascular toxicity. To investigate the potential involvement of iron response element 1 (IRP1) protein in the vascular endothelium during Pb exposure, human umbilical vein endothelial cells (HUVEC) were treated with different concentrations of lead nitrate, 30 μM iron sulfate, or 100 μM deferoxamine. PD98059, a specific inhibitor of the mitogen-activated protein kinase kinase (MEK) activator, was administered to block the ERK/MAPK pathway. Western blotting was used to detect the expression of IRP1 and p-ERK1/2, and microscopy, and co-immunoprecipitation was used to show the association between IRP1 and p-ERK1/2. In vitro measurements revealed a decrease in IRP1 and activated ERK1/2 in the membrane following Pb treatment. HUVEC treated with PD98059 enhanced the levels of membrane IRP1 and efficiently inhibited the effect of Pb on the levels of membrane IRP1. Partial IRP1 co-localization existed with p-ERK1/2 in the membrane, and Pb treatment produced an obvious decrease in the amount of IRP1 that co-localized with p-ERK1/2. Co-immunoprecipitation further revealed a possible association between IRP-1 and p-ERK1/2. Collectively, Pb specifically induced the dysregulation of IRP1 protein by activating the ERK1/2 signaling pathway in the plasma membrane, indicating a novel role for IRP1 and the ERK/MAPK pathway in vascular endothelial functions.

Modulation of lead biohazards using a combination of epicatechin and lycopene in rats

The toxicity of many heavy metals is due to their ability to cause oxidative damage to tissues. Lead is one of the most important metals that pollute the natural environment due to man’s impact The aim of this study is to investigate the potential protective effect of epicatechin alone or combined with lycopene against toxicity of lead in male rats. Five groups of rats were involved in this study; the first was control while the other four injected with lead acetate (100 mg/kg BW) subcutaneous for 2 weeks. On the other hand, the third, fourth and fifth groups were injected with epicatechin, lycopene or epicatechin + lycopene, respectively. Results obtained showed that, the combined treatment (epicatechin + lycopene) exert its effects (100%) against toxic effects against lead by lowering the liver enzymes alanine transaminase (ALT), aspartate transaminase (AST), alkaline phosphatase (ALP) and gamma glutamyle transferase (GGT) activities and decrease lipid peroixdation (MDA) and enhances the superoxide dismutase (SOD) activity. The high-density lipoprotein cholesterol (HDL-c) level was significantly decreased and low-density lipoprotein cholesterol (LDL-c) level was statistically significantly increased in lead-injected rats as compared with control group. The combined treatment with epicatechin and lycopene justify these levels to nearly normal values. The erythrocyte level of total glutathione was decreased in lead-injected rats as compared with control group ( p < 0.001). The combined effect is significantly higher than individual treatment lycopene alone or epicatechin. A negative correlation was found between the blood lead and SOD (r = −0.6) and glutathione (r = −0.81) while a positive correlation with MDA level (r = 0.7).

HFE H63D polymorphism as a modifier of the effect of cumulative lead exposure on pulse pressure: the Normative Aging Study

BACKGROUND

Cumulative lead exposure is associated with a widened pulse pressure (PP; the -difference between systolic and diastolic blood pressure), a marker of arterial stiffness and a predictor of cardiovascular disease. Polymorphisms in the hemochromatosis gene (HFE) have been shown to modify the impact of cumulative lead exposure on measures of adult cognition and cardiac function.

OBJECTIVES

We examined whether the HFE mutations modify the impact of lead on PP in -community-dwelling older men.

METHODS

We examined 619 participants with a total of 1,148 observations of PP from a substudy of bone lead levels (a measure of cumulative exposure, measured by in vivo K-shell X-ray fluorescence) and health in the Normative Aging Study between 1991 and 2001. Linear mixed-effects regression models with random intercepts were constructed.

RESULTS

Of the 619 subjects, 138 and 72 carried the HFE H63D and C282Y variants, respectively. After adjusting for age; education; alcohol intake; smoking; daily intakes of calcium, sodium, and potassium; total calories; family history of hypertension; diabetes; height; heart rate; high-density lipoprotein (HDL); total cholesterol:HDL ratio; and waist circumference, baseline bone lead levels were associated with steeper increases in PP in men with at least one H63D allele (p-interaction = 0.03 for tibia and 0.02 for patella) compared with men with only the wild types or C282Y variant.

CONCLUSIONS

The HFE H63D polymorphism, but not the C282Y mutation, appears to enhance susceptibility to the deleterious impact of cumulative lead on PP, possibly via prooxidative or pro-inflammatory mechanisms.

Blood lead levels association with 18-month all-cause mortality in patients with chronic peritoneal dialysis

BACKGROUND

The clinical significance of blood lead levels (BLLs) in chronic peritoneal dialysis (CPD) patients was undetermined prior to this study.

METHODS

A total of 315 patients on CPD were included in this 18-month prospective study. BLLs measured at baseline were categorized according to a BLL tertile of high (>8.66 microg/dL), middle (5.62-8.66 microg/dL) and low (<5.62 microg/dL) for cross-sectional analyses. Mortality and cause of death were recorded for longitudinal analyses.

RESULTS

At baseline, patients with high BLLs had a trend of higher parathyroid hormone and lower residual renal function than patients in other groups. Stepwise multiple regression analysis found that parathyroid hormone positively correlated and residual renal function negatively correlated with logarithmic-transformed BLLs in CPD patients after other confounders were adjusted. At the end of follow-up, 37 (11.7%) patients had died. Kaplan-Meier analysis showed that patients with high BLLs had greater mortality than those with middle and low BLLs (P = 0.008). Cox multivariate analysis showed that, using the low BLL group as the reference, basal high BLLs (hazard ratio [HR] = 3.745, 95% confidence interval [95% CI] = 1.218-11.494, P = 0.001) and middle BLLs (HR = 1.867, 95% CI = 1.618-2.567, P = 0.001) were associated with increased HR for all-cause mortality for CPD patients. There is a significant trend (P < 0.001) of HR for mortality trend tests among the three study groups.

CONCLUSIONS

BLLs are associated with residual renal function and hyperparathyroidism and are related to increased HR for all-cause 18-month mortality in CPD patients.

Maternal blood lead levels and the risk of pregnancy-induced hypertension: the EDEN cohort study

BACKGROUND

Prior studies revealed associations of environmental lead exposure with risks of hypertension and elevated blood pressure.

OBJECTIVE

We examined the effect of blood lead levels on blood pressure and the incidence of pregnancy-induced hypertension (PIH) in the second and third trimesters of pregnancy.

METHODS

One thousand seventeen pregnant women were enrolled in two French municipalities between 2003 and 2005 for the EDEN (Etude des Déterminants pré et post natals du développement et de la santé de l' Enfant) cohort study. Blood lead concentrations were measured by atomic absorption spectrometry in mothers between 24 and 28 weeks of gestation.

RESULTS

PIH was diagnosed in 106 subjects (10.9%). Age, parity, weight gain, alcohol, smoking habits, and calcium supplementation were comparable between hypertensive and nonhypertensive women. Lead levels were significantly higher in PIH cases (mean +/- SD, 2.2 +/- 1.4 microg/dL) than in normotensive patients (1.9 +/- 1.2 microg/dL; p = 0.02). Adjustment for potential confounder effects slightly attenuated but did not eliminate the significant association between blood lead levels and the risk of PIH (adjusted odds ratio of PIH = 3.3; 95% confidence interval, 1.1-9.7). We also observed geographic differences in lead exposure and in the incidence of PIH and found significant correlations between blood lead levels and unadjusted as well as adjusted systolic and diastolic blood pressures after 24 weeks of gestation.

CONCLUSIONS

These findings confirm the relationship between blood lead levels at mid-pregnancy and blood pressure and suggest that environmental lead exposure may play an etiologic role in PIH.

Asthma, environmental risk factors, and hypertension among Arab Americans in metro Detroit

Asthma and obesity-related health problems disproportionately impact low-income ethnic minority communities residing in urban areas. Environmental risk factors, particularly those related to housing and indoor air, may impact the development or exacerbation of asthma. There is increasing evidence to suggest a link between obesity-related health problems and asthma. Previous studies have also reported that immigrant status may influence myriad risk factors and health outcomes among immigrant populations. The Arab American Environmental Health Project (AAEHP) was the first study to explore environmental health problems among Arab Americans. This paper examined whether hypertensive status modified the relationship between environmental risk factors and asthma among Arab Americans in metro Detroit. An environmental risk index (ERI) was used to quantify household environmental risk factors associated with asthma. Physician diagnosed hypertension was self-reported, and asthma status was determined using responses to a validated symptoms checklist and self-reported diagnosis by a physician. Hypertension significantly modified the relationship between ERI and asthma in this study population. The positive association between household environmental risk factors and asthma was stronger among participants diagnosed with hypertension. Effect modification of the relationship between environmental risk factors and asthma could have serious implications among high-risk communities. However, further research is needed to elucidate the relationships between hypertension, environmental risk factors, and asthma.

Environmental risk factors for heart disease

In this review, we discuss current evidence linking environmental pollutants to cardiovascular disease (CVD). Extensive evidence indicates that environmental factors contribute to CVD risk, incidence, and severity. Migrant studies show that changes in the environment could substantially alter CVD risk in a genetically stable population. Additionally, CVD risk is affected by changes in nutritional and lifestyle choices. Recent studies in the field of environmental cardiology suggest that environmental toxins also influence CVD. Exposure to tobacco smoke is paradigmatic of such environmental risk and is strongly and positively associated with increased cardiovascular morbidity and mortality. In animal models of exposure, tobacco smoke induces endothelial dysfunction and prothrombotic responses and exacerbates atherogenesis and myocardial ischemic injury. Similar mechanism may be engaged by other pollutants or food constituents. Several large population-based studies indicate that exposure to fine or ultrafine particulate air pollution increases CVD morbidity and mortality, and the plausibility of this association is supported by data from animal studies. Exposure to other chemicals such as polyaromatic hydrocarbons, aldehydes, and metals has also been reported to elevate CVD risk by affecting atherogenesis, thrombosis, or blood pressure regulation. Maternal exposure to drugs, toxins, and infection has been linked with cardiac birth defects and premature CVD in later life. Collectively, the data support the notion that chronic environmental stress is an important determinant of CVD risk. Further work is required to assess the magnitude of this risk fully and to delineate specific mechanisms by which environmental toxins affect CVD.

Mechanisms of lead-induced hypertension and cardiovascular disease

Lead is a ubiquitous environmental toxin that is capable of causing numerous acute and chronic illnesses. Population studies have demonstrated a link between lead exposure and subsequent development of hypertension (HTN) and cardiovascular disease. In vivo and in vitro studies have shown that chronic lead exposure causes HTN and cardiovascular disease by promoting oxidative stress, limiting nitric oxide availability, impairing nitric oxide signaling, augmenting adrenergic activity, increasing endothelin production, altering the renin-angiotensin system, raising vasoconstrictor prostaglandins, lowering vasodilator prostaglandins, promoting inflammation, disturbing vascular smooth muscle Ca(2+) signaling, diminishing endothelium-dependent vasorelaxation, and modifying the vascular response to vasoactive agonists. Moreover, lead has been shown to cause endothelial injury, impede endothelial repair, inhibit angiogenesis, reduce endothelial cell growth, suppress proteoglycan production, stimulate vascular smooth muscle cell proliferation and phenotypic transformation, reduce tissue plasminogen activator, and raise plasminogen activator inhibitor-1 production. Via these and other actions, lead exposure causes HTN and promotes arteriosclerosis, atherosclerosis, thrombosis, and cardiovascular disease. In conclusion, studies performed in experimental animals, isolated tissues, and cultured cells have provided compelling evidence that chronic exposure to low levels of lead can cause HTN, endothelial injury/dysfunction, arteriosclerosis, and cardiovascular disease. More importantly, these studies have elucidated the cellular and molecular mechanisms of lead's action on cardiovascular/renal systems, a task that is impossible to accomplish using clinical and epidemiological investigations alone.

Effect of grape seed extract on lead induced hypertension and heart rate in rat

The main objective of this study was to evaluate the potential protective effect of red Grape Seed Extract (GSE) on lead induced hypertension (HTN) and Heart Rate (HR) in male Wistar rats. The rats were randomly assigned to one of 4 groups: Each group received lead acetate (100 ppm in drinking water), GSE (100 mg kg(-1), orally) or Lead + GSE for 45 days. Another group assigned as control group provided with tap water and regular pellet food. The Systolic Blood Pressure (SBP) and heart rate were determined by tail plethysmography coupled to a computer system. There was a sustained elevation of SBP in lead exposed rats that significantly increased at day 18 (lead treated, 112.7 +/- 2.7 mmHg, vs. control, 105.6 +/- 2.6 mmHg, n = 10, p < 0.05) and reached a maximum level at day 36 (lead treated, 124.9 +/- 2.3 mmHg, vs. control, 103.6 +/- 3.1 mmHg, n = 10, p < 0.001). However, the other three groups; showed no significant changes in SBP. Furthermore, the heart rate was increased sustainly in lead exposed animals that was statistically significant at days 36 and 45 (lead treated group, 404.5 +/- 9.4 vs. control group, 381.7 +/- 6.7, n = 10, p < 0.05). The blood lead level in both lead and lead + GSE treated groups was increased significantly compared with control and GSE treated groups (p < 0.001). However, GSE administration had no effect on the blood lead level in lead treated group. According to the result of this study, it may be concluded that GSE could have beneficial effect in protecting the cardiovascular system through its antioxidant activity against oxidative stress.

Blood lead levels, malnutrition, inflammation, and mortality in patients with diabetes treated by long-term hemodialysis

BACKGROUND

Blood lead levels (BLLs) are associated with mortality in the general population. The clinical significance of BLLs in long-term hemodialysis (HD) patients with diabetes is unknown.

STUDY DESIGN

A cross-sectional and 1-year prospective study.

SETTINGS & PARTICIPANTS

211 patients with diabetes on long-term HD therapy at 3 centers.

PREDICTOR

BLLs measured before HD at baseline, categorized as abnormal (>20 microg/dL), high normal (10 to 20 microg/dL), and low normal (<10 microg/dL).

OUTCOMES & MEASUREMENTS

Malnutrition, defined as serum albumin level less than 3.6 g/dL, and inflammation, defined as high-sensitivity C-reactive protein level greater than 3 mg/dL, for cross-sectional analyses. Mortality and cause of death for longitudinal analyses.

RESULTS

34, 112, and 65 patients had abnormal, high-normal, and low-normal BLLs at baseline. At baseline, patients with abnormal BLLs had a greater proportion of malnutrition (14.7% versus 1.5% and 11.6%; P = 0.01) and inflammation (76.5% versus 52.3% and 50.9%; P = 0.01) than those with low- and high-normal BLLs. Backward stepwise regression analysis found that high-sensitivity C-reactive protein level correlated positively and albumin level correlated negatively with BLLs after other confounders were adjusted. At the end of follow-up, 16 patients had died. Kaplan-Meier analysis showed that patients with an abnormal BLL had greater mortality than those with low and low-normal BLLs (P = 0.004).

LIMITATIONS

Small sample size, sparse outcomes, and limited follow-up.

CONCLUSIONS

BLL may contribute to inflammation and nutritional status in long-term HD patients with diabetes on long-term HD therapy and may relate to 1-year mortality in these patients.

Cumulative community-level lead exposure and pulse pressure: the normative aging study

BACKGROUND

Pulse pressure increases with age in industrialized societies as a manifestation of arterial stiffening. Lead accumulates in the vasculature and is associated with vascular oxidative stress, which can promote functional and structural vascular disease.

OBJECTIVES

We tested the hypothesis that cumulative community-level lead exposure, measured with K-X-ray fluorescence, is associated with pulse pressure in a cohort of adult men.

METHODS AND RESULTS

In a cross-sectional analysis of 593 men not treated with antihypertensive medication, tibia lead was positively associated with pulse pressure (p < 0.001). Adjusting for age, race, diabetes, family history of hypertension, education, waist circumference, alcohol intake, smoking history, height, heart rate, fasting glucose, and total cholesterol-to-HDL ratio, increasing quintiles of tibia lead remained associated with increased pulse pressure (ptrend = 0.02). Men with tibia lead above the median (19.0 microg/g) had, on average, a 4.2-mmHg (95% confidence interval, 1.9-6.5) higher pulse pressure than men with tibia lead level below the median. In contrast, blood lead level was not associated with pulse pressure.

CONCLUSIONS

These data indicate that lead exposure may contribute to the observed increase in pulse pressure that occurs with aging in industrialized societies. Lead accumulation may contribute to arterial aging, perhaps providing mechanistic insight into the observed association of low-level lead exposure with cardiovascular mortality.

Effect of lead on the levels of some immunoregulatory cytokines in occupationally exposed workers

Lead (Pb) may affect humoral and cellular immunity, acting on lymphocytes as well as on granulocytes and monocytes. Cytokines and nitric oxide (NO) play a central role in the immune balance. In this study, plasma levels of nitrites and nitrates (NOx), IL2, IL4, IL6, IL10, TNF-alpha and INF-gamma, were measured in healthy workers with very low (Pb-B=3.2-18.0 microg/dL) and low (Pb-B=9.1-46.0 microg/dL) Pb-exposure compared to non-exposed workers. Low Pb-exposed workers (Pb-B=9.1 -46.0 microg/ dL) were found to have significantly higher plasma IL-10 levels, and tendentially higher plasma TNF-alpha levels compared to non-exposed workers. This is the first report of a significant increase of plasma IL-10 levels in Pb-exposed workers. Plasma IL-10 increase was influenced by blood Pb levels even after correction for main confounding factors. No difference was found in plasma NOx levels between Pb-exposed and non-exposed workers, which is in agreement with previous findings exclusively regarding groups in the general population. Low Pb-exposure can induce an increase of pro-inflammatory cytokines, such as TNF-alpha, with a consequent increase of other cytokines, such as IL-10, considered a T cell cross-regulatory factor, suggesting possible interference of Pb in the system of immunophlogosis.

Interplay of reactive oxygen species and nitric oxide in the pathogenesis of experimental lead-induced hypertension

1. Lead is a common environmental and industrial toxin that can cause a variety of acute and chronic illnesses. For example, chronic exposure to low levels of lead has been shown to raise arterial pressure and promote renal and cardiovascular complications. 2. Several mechanisms have been identified by which chronic lead exposure can cause hypertension and cardiovascular disease. In recent years, increasing evidence has emerged pointing to the role of oxidative stress as a major mediator of lead-induced hypertension. 3. The present article provides an overview of the published studies on this subject.

Erythrocyte acetylcholinesterase activity as a surrogate indicator of lead-induced neurotoxicity in occupational lead exposure in Abeokuta, Nigeria

Dose-effect and dose-response relationships in occupational neurotoxicology are rarely studied by means of biochemical methods. In order to investigate the potential neurotoxic effects of lead during occupational exposure to this metal, the activity of erythrocyte acetylcholinesterase (AcChE), as well as blood pressure and pulse, were determined in various artisans in Abeokuta, Nigeria, who have been shown to be occupationally exposed to lead, and these were related to blood lead levels. AcChE activity in the artisans was inhibited to varying extents. While AcChE activity was inhibited to the tune of 39% in the male petrol station attendants, the inhibition amounted to 32% in female petrol station attendants. In other artisans, AcChE inhibition ranged from 31% in the welders to 38% in painters. The lowest inhibition of 15% was obtained in the panel beaters. Correlations, as calculated by Pearson's method, revealed a significant (p<0.001) inverse linear relationship between AcChE activity and blood lead levels (r=-0.40; y=-120.38x+13935.59; p<0.001). Blood pressure and pulse were not significantly different between control and lead-exposed subjects. Our findings suggest that erythrocyte AcChE activity could be used as a biomarker of lead-induced neurotoxicity in occupationally exposed subjects.

Clinical evidence for lead-induced inhibition of nitric oxide formation

Lead exposure has been associated with increased cardiovascular risk, which may result, at least in part, from lead-induced increases in oxidative stress and depressed nitric oxide (NO) availability. However, no previous clinical study has examined whether lead exposure is associated with significant effects on biomarkers of NO activity (plasma nitrites, nitrates, and cyclic guanosine 3',5'-monophosphate; cGMP). We investigated whether there is an association between the circulating concentrations of nitrites, nitrates, and cGMP and the concentrations of lead in whole blood (B-Pb) or plasma (P-Pb) from 62 lead-exposed subjects (30 men and 32 women). P-Pb was determined by inductively coupled plasma mass spectrometry and B-Pb by graphite furnace atomic absorption spectrometry. Plasma nitrite and nitrate concentrations were measured using an ozone-based chemiluminescence assay. Plasma cGMP concentrations were measured using a commercial enzyme immunoassay. We found a negative correlation between plasma nitrite and B-Pb concentrations (r = -0.358; P = 0.004), and between plasma nitrite and P-Pb concentrations (r = -0.264; P = 0.038), thus suggesting increased inhibition of NO formation with increasing B-Pb or P-Pb concentrations. However, no significant correlations were found between plasma nitrate or cGMP and B-Pb or P-Pb concentrations (all P > 0.05). These findings suggest a significant inhibitory effect of lead exposure on NO formation and provide clinical evidence for a biological mechanism possibly involved the association between lead exposure and increased cardiovascular risk.

Stress as a potential modifier of the impact of lead levels on blood pressure: the normative aging study

BACKGROUND

Lead exposure and psychological stress have been independently associated with hypertension in various populations, and animal studies suggest that when they co-occur, their effects may be exacerbated.

OBJECTIVES

We examined whether psychological stress modifies the impact of cumulative lead exposure (measured as bone lead levels) on hypertension and blood pressure in Boston-area community-exposed men participating in the Normative Aging Study.

METHODS

We evaluated the modifying effect of stress on lead exposure on baseline hypertension status (513 participants) and on blood pressure in those without hypertension (237 participants), cross-sectionally. In baseline nonhypertensives, we examined the same risk factors in relation to prospective risk of developing hypertension.

RESULTS

Cross-sectional analysis revealed a positive interaction between stress and tibia lead on systolic blood pressure, after adjusting for age, body mass index, family history of high blood pressure, education, smoking, alcohol consumption, physical activity, and nutritional factors. In prospective multivariate analyses, high stress also modified the effect of tibia lead and patella lead on the risk of developing hypertension. Those reporting high stress had 2.66 [95% confidence interval (CI), 1.43-4.95] times the risk of developing hypertension per standard deviation increase in tibia lead and had 2.64 (95% CI, 1.42-4.92) times the risk per standard deviation increase in patella lead.

CONCLUSION

To our knowledge, these are the first analyses to look at interactive effects of stress and lead on hypertension in humans. These results suggest that the effect of lead on hypertension is most pronounced among highly stressed individuals, independent of demographic and behavioral risk factors.

Rapid identification of oxidation-induced conformational changes by kinetic analysis

Protein oxidation by reactive oxygen species is known to result in changes in the structure and function of the oxidized protein. Many proteins can tolerate multiple oxidation events before altering their conformation, while others suffer gross changes in conformation after a single oxidation event. Additionally, reactive oxygen species have been used in conjunction with mass spectrometry to map the accessible surface of proteins, often after verification that the oxidations do not alter the conformation. However, detection of oxidation-induced conformational changes by detailed kinetic oxidation analysis of individual proteolytic peptides or non-mass spectrometric analysis is labor-intensive and often requires significant amounts of sample. In this work, we describe a methodology to detect oxidation-induced conformational changes in proteins via direct analysis of the intact protein. The kinetics of addition of oxygen to unmodified protein are compared with the kinetics of addition of oxygen to the mono-oxidized protein. These changes in the rate of oxidation of the oxidized versus the non-oxidized protein are strongly correlated with increases in the random coil content as measured by the molar ellipticity at 198 nm. This methodology requires only small amounts of protein, and can be done rapidly without additional sample handling or derivatization.