Jolanta Antonowicz-Juchniewicz

Metabonomic analysis of serum of workers occupationally exposed to arsenic, cadmium and lead for biomarker research: a preliminary study.

Environmental metabonomics is the application of metabonomics to characterize the interactions of organisms with their environment. Metabolic profiling is an exciting addition to the armory of the epidemiologist for the discovery of new disease risk biomarkers and diagnostics. This work is a continuation of research searching for preclinical serum markers in a group of 389 healthy smelter workers exposed to lead, cadmium and arsenic. Changes in the metabolic profiles were studied using Proton Nuclear Magnetic Resonance Spectroscopy on pooled serum samples from both the metal exposed and control groups. These multivariate metabonomic datasets were analyzed with Principal Component Analysis and Partial Least Squares Discriminant Analysis. Analysis of metabolic profiles of people exposed to heavy metals suggests energy metabolism disturbance induced by heavy metals. Changes in lipid fraction (very-low-density lipoprotein - VLDL, low-density lipoprotein - LDL), unsaturated lipids and in the level of amino acids suggest perturbation of the metabolism of lipids and amino acids. This study illustrated the high reliability of NMR-based metabonomic profiling on the study of the biochemical effects induced by the mixture of heavy metals. This approach is capable of identifying intermediate biomarkers of response to toxicants at environmental/occupational concentrations, paving the way to its use in a monitoring of smelter workers exposed to low doses of lead, cadmium and arsenic.

Relation between occupational exposure to lead, cadmium, arsenic and concentration of cystatin C.

UNLABELLED Lead, cadmium and arsenic represent well recognized toxic agents which in a specific manner disturb function of cardiovascular system. Cystatin C has been accepted to be a significant prognostic factor for cardiovascular diseases. The study aimed at defining relationship between occupational exposure to lead, cadmium and arsenic on one hand and concentration of cystatin C on the other. The studies were performed on 282 men occupationally exposed to lead, cadmium and arsenic. Among the tested individuals several groups of persons were distinguished: exposed exclusively to lead (Pb group), cadmium (Cd group), arsenic (As group), to lead and cadmium (Pb/Cd group), to lead and arsenic (Pb/As group) or to cadmium and arsenic (Cd/As group). In all the individuals serum concentration of cystatin C was estimated. Concentration of cystatin C was found to be significantly higher in Pb group than in Cd and As groups, also in Pb/Cd group higher than in Cd group and in Pb/As group than in As group. Positive linear correlations were established between Pb concentration in blood (Pb-B) and serum concentration of cystatin C (r=0.59; p<0.05) as well as between urinary concentration of As (As-U) and serum concentration of cystatin C (r=0.41; p<0.05). Regression analysis demonstrated that higher blood level of lead, higher urinary level of arsenic, more advanced age and higher body mass index represented independent risk factors of an increased serum concentration of cystatin C in the group of persons exposed to lead, cadmium and arsenic. CONCLUSIONS Higher blood level of lead and higher urinary level of arsenic represented independent risk factors of an increased serum concentration of cystatin C in the group of persons occupationally exposed to lead, cadmium and arsenic. Concentration of lead in blood was significantly influencing serum concentration of cystatin C. The highest mean serum concentration of cystatin C was detected in the group of foundry workers exposed simultaneously to lead and arsenic.

Application of classic epidemiological studies and proteomics in research of occupational and environmental exposure to lead, cadmium and arsenic

The metals/metaloids lead (Pb), cadmium (Cd), and arsenic (As) are among the leading toxic agents in the environment. They represent an important source of dangerous exposure in humans, particularly in industry workers. The most serious consequences of exposure to those heavy metals are cancers and cardiovascular diseases. In studies of human exposure to Pb, Cd, and As alone and in a mixture markers signaling the subtle, early lesions that occur in the human body are still lacking. It is appropriate to develop high throughput techniques and use non-invasive materials. The techniques currently used in classic epidemiological studies allow selection of single markers of changes of exposure to chronic low dose levels of metal/metaloids mixtures. However, application of proteomic techniques in such studies may allow the selection of new biomarkers of environmental and occupational exposure to heavy metals characterized by high sensitivity and specificity. As presented in our review paper, proteomic techniques in combination with appropriate statistical methods allow the selection of potential markers to estimate the changes in the human body when exposed to those heavy metals.

Proteomic analysis of serum of workers occupationally exposed to arsenic, cadmium, and lead for biomarker research: a preliminary study.

The main factor of environmental contamination is the presence of the heavy metals lead, cadmium, and arsenic. The aim of serum protein profile analysis of people chronically exposed to heavy metals is to find protein markers of early pathological changes. The study was conducted in a group of 389 healthy men working in copper foundry and 45 age-matched non-exposed healthy men. Toxicological test samples included whole blood, serum, and urine. Thirty-seven clinical parameters were measured. Based on the parameters values of the healthy volunteers, the centroid in 37-dimensional space was calculated. The individuals in the metal-exposed and control groups were ordered based on the Euclidean distance from the centroid defined by the first component according to Principal Component Analysis (PCA). Serum samples of two individuals, one from the control and one from the metal-exposed group, were chosen for proteomic analysis. In optimized conditions of two-dimensional gel electrophoresis (2-DE), two protein maps were obtained representing both groups. Twenty-eight corresponding protein spots from both protein maps were chosen and identified based on PDQuest analysis and the SWISS-2DPAGE database. From a panel of six proteins with differences in expression greater than a factor of two, three potential markers with the highest differences were selected: hemoglobin-spot 26 (pI 7.05, Mw 10.53), unidentified protein-spot 27 (pI 6.73, Mw 10.17), and unidentified protein-spot 25 (pI 5.75, Mw 12.07). Further studies are required to prove so far obtained results. Identified proteins could serve as potential markers of preclinical changes and could be in the future included in biomonitoring of people exposed to heavy metals.

The influence of the intensity of smoking and years of work in the metallurgy on pro-oxidant/antioxidant balance in the blood of smelters.

The aim of this study was to investigate the effect of cigarette smoking and occupational exposure to heavy metals on the degree of pro-oxidant/antioxidant imbalance in smelters. The investigations were performed on the blood and urine of 400 subjects: 300 male copper smelters and 100 nonexposed male subjects. Biological material was divided into three groups: nonsmokers, those who smoked less than 20 cigarettes a day and those who smoked more than 20 cigarettes a day. The results showed a significant increase in the concentration of lead, cadmium and arsenic in the blood and urine of smelters, while smoking more than 20 cigarettes a day caused a further increase in the concentration of these metals. The level of malondialdehyde was approximately twofold higher in the plasma of the smelters compared to the control group. We have observed a disturbance in the level of antioxidants in erythrocyte lysate manifested by an increase in metallothionein and glutathione concentrations as well as superoxide dismutase and glutathione peroxidase activities and the decrease in glutathione S-transferase activity. Cigarette smoking, years of work in metallurgy and age of smelters were additional factors significantly affecting the pro-oxidant/antioxidant balance.

Asymmetric dimethylarginine in hematological malignancies: a preliminary study

Asymmetric dimethylarginine (ADMA) is a product of protein hydrolysis and an endogenous competitive inhibitor of nitric oxide synthase. It is considered a new independent risk factor for endothelial dysfunction and cardiovascular diseases. Increased protein turnover, oxidative stress and impaired dimethylarginine dimethylaminohydrolase activity occurring in hematological malignancies may lead to increased dimethylarginines production. We have measured ADMA, symmetric dimethylarginine (SDMA) and l-arginine plasma levels in 43 patients with different types of hematological malignancies and in control group of 43 healthy volunteers. Mean ADMA and l-arginine plasma levels were higher in hematological group than in control group (1.59 vs 0.64; p < 0.001 and 34.84 vs 28.35; p = 0.044 respectively). Mean plasma levels of SDMA were not significantly different between the groups. Elevated ADMA plasma levels in patients with hematological malignancies interfere with nitric oxide metabolism and may influence their prognosis. Further prognostic studies are postulated to assess this phenomenon.

Plasma asymmetric dimethylarginine predicts restenosis after coronary angioplasty

Introduction Asymmetric dimethylarginine (ADMA) is an endogenous competitive inhibitor of endothelial nitric oxide synthase. Asymmetric dimethylarginine may influence the process of restenosis after coronary angioplasty. The aim of the study was to determine if initial plasma ADMA level could predict restenosis after coronary angioplasty and stenting. Material and methods The study group consisted of 60 consecutive patients (10 women and 50 men, average age 58.9 ±10.4 years old), who underwent percutaneous coronary angioplasty with bare metal stenting for stable coronary artery disease. All patients underwent follow-up coronary angiography after a 6-month period. Patients were divided into two groups, one with restenosis (n = 22), and the other one without restenosis (n = 38). In addition to measuring acknowledged restenosis risk factors, plasma ADMA level was measured before initial angiography. Results Asymmetric dimethylarginine plasma level was significantly higher in the group with restenosis than in the group without restenosis (1.94 ±0.94 µmol/l vs. 0.96 ±0.67 µmol/l; p < 0.05). L-arginine/ADMA ratio was also decreased in the group with restenosis, when compared with the group without restenosis (p < 0.05). Multivariate logistic regression revealed that independent restenosis risk factors were characterised by an initially high ADMA level (p < 0.01), advanced age (p < 0.05) and low level of HDL cholesterol (p < 0.05). Conclusions Pre-procedural elevated plasma ADMA level increases the risk of restenosis in patients who underwent coronary angioplasty and stenting with bare metal stents.

Relationship between occupational exposure to lead and local arterial stiffness and left ventricular diastolic function in individuals with arterial hypertension

Relationship between occupational exposure to lead and frequency of complications in persons with arterial hypertension has been poorly investigated. This study aimed at evaluation of the relationship between occupational exposure to lead and manifestation of an increased local arterial stiffness and left ventricular diastolic dysfunction. The studies included 105 men (mean age: 44.47±9.12years) with arterial hypertension, treated with hypotensive drugs: group I - men occupationally exposed to lead (n=53), and group II - men not exposed to lead (n=52). In echocardiographic examination, the left ventricular diastolic dysfunction was diagnosed significantly more frequently in group I than in group II. In eTracking examination mean values of stiffness parameter (β), augmentation index (AI) and one-point pulse wave velocity (PWV-β) were significantly higher and mean values of arterial compliance (AC) were significantly lower in group I than in group II. The logistic regression showed that in the group of persons with arterial hypertension occupationally exposed to lead a more advanced age, higher blood lead concentration and higher mean values of augmentation index represent independent risk factors of left ventricular diastolic dysfunction. The multifactorial regression showed that amongst persons with arterial hypertension occupationally exposed to lead higher blood zinc protoporphyrin concentration, a more advanced age and higher value of body mass index (BMI) represent independent risk factors of an increased local arterial stiffness. In summary, we should note that in the group of persons with arterial hypertension occupationally exposed to lead the study has demonstrated a significantly more frequent manifestation of left ventricular diastolic dysfunction and an increase in local arterial stiffness.