Influence of heavy metal mixtures on erythrocyte metabolism

Abstract

Exposure of foundry workers to mixtures of different heavy metals is a very important toxicological problem. In this paper the estimation of the effects of lead, zinc, and copper on erythrocyte metabolism is presented. Concentrations of copper and zinc at work posts of the group examined did not exceed TLV, while lead concentration was 1.5 to 4 times higher than TLV. Erythrocyte metabolism was measured through activities of such glycolytic pathway enzymes as PFK, PGI, PK, aldolase and G6-PD from the hexose monophosphate pathway. Additionally the free erythrocyte protoporphyrin (FEP) level, D-ALA activity, serum GSH level, 2,3 DPG level in erythrocytes and lactic acid production during a 2-h incubation of red blood cells (RBC) was estimated. The blood-lead level, FEP level, copper concentration in erythrocytes in exposed group were significantly higher than in control group while the zinc level in erythrocytes was significantly lower. Measuring erythrocyte metabolism we showed that the activity of PGI, PFK, aldolase, lactic production and 2,3 DPG levels was significantly higher in the exposed group, probably as a result of anaerobic glycolysis activation.

Analysis of cellular responses of macrophages to zinc ions and zinc oxide nanoparticles: a combined targeted and proteomic approach

“…First, zinc stress induced a higher level of pyruvate in cells, as shown in Figure 6A. This is in line with the activation of the glycolytic metabolism observed in occupational medicine 53 , and suggested that pyruvate is a critical metabolite for survival in presence of a zinc stress, as in neuronal cells 54,55 . Our results demonstrate that pyruvate acts as a survival factor upon zinc stress, both for zinc ion ( Figure 6B), zinc oxide ( Figure 6C) and cationized zinc oxide ( Figure 6D).…”

“…6A. This is in line with the activation of the glycolytic metabolism observed in occupational medicine, 53 and suggested that pyruvate is a critical metabolite for survival in the presence of a zinc stress, as in neuronal cells. 54,55 Our results demonstrate that pyruvate acts as a survival factor upon zinc stress, both for zinc ion (Fig.…”

The metabolism of carbohydrates and lipid peroxidation in lead-exposed workers

“…Nevertheless, the association between lead exposure and G6PD activity has been refuted in a study by Rogers et al (1971) who experimentally induced lead poisoning in rabbits. Paglia et al (1975) investigated enzyme activities in human erythrocytes exposed to lead in vitro and obtained data consistent with a study by Antonowicz et al (1990) who examined lead-exposed workers. Due to the fact that the mean PbB values (39.9 ± 12 μg/dl in the control group and 82.1 ± 43 μg/dl in the examined group) are much higher than PbB mean levels in the present study, these data are difficult to compare.…”

“…The results obtained in that study suggested that glycolytic impairment had not appeared. Antonowicz et al (1990), however, revealed increased activities of phosphoglucose isomerase, phosphofructokinase, and FBA, as well as 2,3-diphosphoglucose and lactate levels in the RBCs of lead-exposed workers. This suggests that heavy metal stress may induce increased energy demand in RBCs, which results in enhanced anaerobic glycolysis.…”

Pediatric reference ranges for zinc protoporphyrin

“…ZPPs are heme precursors that accumulate in iron deficiency and in lead poisoning. Lead inhibits iron binding to the heme molecule (by interfering with the activity of the enzymes δ-aminolevulinic dehydratase (ALA) and ferro-chelatase) leading to ZPP accumulation [22,23]. A significant positive correlation was demonstrated between blood-lead concentrations >20 μg/dL (36.8 μmol/mol heme) and ZPP concentrations [24][25][26].…”