Positive Association between Endothelium–Platelet Microparticles and Urinary Concentration of Lead and Cadmium in Adolescents and Young Adults

(1) Background: In previous research, higher levels of urine heavy metals, especially lead and cadmium, have been associated with increased cardiovascular risk. However, there is no information linking exposure to heavy metal to endothelial and platelet microparticles (EMPs and PMPs), particularly in the younger population, which are novel biomarkers of endothelial dysfunction. (2) Methods: From a nationwide database, which was incepted in 1992–2000, screening for renal health among Taiwanese school children, a total of 789 subjects were recruited. Cross-sectional analysis was performed to evaluate the association between serum EMPs/PMPs and urine iron, nickel, copper, cadmium, lead, chromium, manganese, and zinc levels in the adolescent and young adult population. (3) Results: After we adjusted the conventional cardiovascular risk factors, CD31+/CD42a− and CD31+/CD42a+ counts, in subjects’ serum, respective markers of EMP and PMP displayed a significant positive dose-response relationship with urinary lead and cadmium levels. Higher quartiles of urine lead and cadmium levels were associated with an increased risk of higher EMPs/PMPs (≥75th percentile) in a multivariate logistic regression model. (4) Conclusion: Higher urinary lead and cadmium concentrations are strongly associated with endothelium–platelet microparticles in this adolescent and young adult population, which could help explain, in part, the mechanism through which heavy metal exposure results in cardiotoxicity.

URINARY LEAD CONCENTRATION IN CHRONIC KIDNEY DISEASE PATIENTS AT NEPHROLOGY CLINIC IN SABAH

Presently, scientific knowledge on the association between urinary lead concentration and renal profile is limited, especially on the characteristic of urinary lead that could aggravate existing kidney disease. This study aims to determine the concentration of urinary lead with serum creatinine and blood urea nitrogen in chronic kidney disease patients and to identify the influences of confounding factors and the blood pressure on the chronic kidney disease patients. Graphite Furnace Atomic Absorption Spectrometer was used to determine the urinary lead concentration. The differences and correlation of urinary lead with serum creatinine, blood urea nitrogen and diastolic blood pressure between the chronic kidney disease patients and control groups were assessed using Mann Whitney U and Spearman correlation tests. Our findings indicated a significantly higher urinary lead concentration in the chronic kidney disease group compared to the control group (p-=0.002). Nevertheless, there is a weak relationship between urinary lead with serum creatinine, blood urea nitrogen and diastolic blood pressure in the chronic kidney disease group (r values: -0.123, 0.101, and 0.127). In addition, sociodemographic factors did not influence the concentration of urinary lead (p>0.05). The urinary lead concentration in the chronic kidney disease group is not substantial, thus the evidence of urinary lead accumulation in chronic kidney disease group who have yet to start renal replacement therapy is inconclusive.

Effect of Dietary Sodium and Potassium Intake on the Mobilization of Bone Lead among Middle-Aged and Older Men: The Veterans Affairs Normative Aging Study

Bone is a major storage site as well as an endogenous source of lead in the human body. Dietary sodium and potassium intake may play a role in the mobilization of lead from bone to the circulation. We examined whether association between bone lead and urinary lead, a marker of mobilized lead in plasma, was modified by dietary intake of sodium and potassium among 318 men, aged 48–93 years, in the Veterans Affairs (VA) Normative Aging Study. Dietary sodium and potassium were assessed by flame photometry using 24-h urine samples, and a sodium-to-potassium ratio was calculated from the resulting measures. Patella and tibia bone lead concentrations were measured by K-shell-x-ray fluorescence. Urinary lead was measured by inductively coupled plasma mass spectroscopy in 24-h urine samples. Linear regression models were used to regress creatinine clearance-corrected urinary lead on bone lead, testing multiplicative interactions with tertiles of sodium, potassium, and sodium-to-potassium ratio, separately. After adjustment for age, body mass index, smoking, vitamin C intake, calcium, and total energy intake, participants in the highest tertile of sodium-to-potassium ratio showed 28.1% (95% CI: 12.5%, 45.9%) greater urinary lead per doubling increase in patella lead, whereas those in the second and lowest tertiles had 13.8% (95% CI: −1.7%, 31.7%) and 5.5% (95% CI: −8.0%, 21.0%) greater urinary lead, respectively (p-for-interaction = 0.04). No statistically significant effect modification by either sodium or potassium intake alone was observed. These findings suggest that relatively high intake of sodium relative to potassium may play an important role in the mobilization of lead from bone into the circulation.

Oxidative Stress Indices as Markers of Lead and Cadmium Exposure Toxicity in Auto Technicians in Ibadan, Nigeria

Auto technicians (auto mechanics, panel beaters, battery chargers, and auto painters) are among the most valuable work force in the society. Reports on oxidative stress in persons occupationally exposed to mixed chemicals abound; however, few have narrowed down specifically on auto technicians, while even fewer have stratified the exposure in the different subgroups of auto technicians. This study evaluated the antioxidant status in auto technicians routinely exposed to lead and cadmium and stratified the results of exposure by different subgroups of auto technicians in Ibadan, Nigeria. Sixty-five apparently healthy males (aged 18 to 65years) were selected based on specific inclusion criteria using a structured questionnaire. Thirty-four were cases consisting of participants routinely working as auto technicians or apprentices(≥2years) while controls were thirty-one nonoccupationally exposed male members of staff/students of the University College Hospital, Ibadan, Nigeria. Blood was collected from all participants and analyzed for the presence of lead, total antioxidant capacity (TAC), and total plasma peroxides (TPP); oxidative stress index (OSI) was calculated. Urine samples collected from all participants were analyzed for the presence of urinary lead and cadmium using standard laboratory methods. Although values of TAC in cases (22538±8726.54) were not statistically different from what was obtained in controls (26741.87±8696.68), TPP and OSI were statistically higher in cases than in controls (183.88±53.39 and 120.16±70.54, respectively, and 0.93±0.45 and 0.49±0.33, respectively). The blood lead level in cases (10.11±4.47) was significantly higher than in controls (7.72±1.22) while elevated urinary lead and cadmium levels were observed in cases (0.65±0.21 and 0.34±0.11, respectively) compared to controls (0.52±0.19 and 0.27±0.10, respectively). Raised TPP and OSI levels—hallmark of active lipid peroxidation—found to be highest among panel beaters compared to others may be prognostic of membrane-damaging diseases in this subgroup of auto technicians.