Jaromir Michałowicz

Bisphenol A--sources, toxicity and biotransformation.

Bisphenol A (BPA) is a chemical compound used in massive amounts in the production of synthetic polymers and thermal paper. In this review, the sources of BPA, which influence its occurrence in the environment and human surrounding will be presented. Data concerning BPA occurrence in food, water and indoor environments as well as its appearance in tissues and body fluids of human body will be shown. The results of in vitro and in vivo studies and the results of epidemiological surveys showing toxic, endocrine, mutagenic and cancerogenic action of BPA will also be discussed. Moreover, data suggesting that exposure of human to BPA may elevate risk of obesity, diabetes and coronary heart diseases will be presented. Finally, biotransformation of BPA in animals, plants and microorganisms (bacteria, fungi, algae), resulting in the formation of various metabolites that exhibit different from BPA toxicity will be described.

Eryptosis-inducing activity of bisphenol A and its analogs in human red blood cells (in vitro study).

Bisphenols are important chemicals that are widely used in the manufacturing of polycarbonates, epoxy resin and thermal paper, and thus the exposure of humans to these substances has been noted. The purpose of this study was to assess eryptotic changes in human erythrocytes exposed (in vitro) to bisphenol A (BPA) and its selected analogs, i.e.,bisphenol F (BPF), bisphenol S (BPS) and bisphenol AF (BPAF). The erythrocytes were incubated with compounds studied at concentrations ranging from 1 to 250μg/mL for 4, 12 or 24h. The results showed that BPA and its analogs increased cytosolic calcium ions level with the strongest effect noted for BPAF. It has also been revealed that all bisphenols analyzed, and BPAF and BPF in particular increased phosphatidylserine translocation in red blood cells, which confirmed that they exhibited eryptotic potential in this cell type. Furthermore, it was shown that BPA and its analogs caused significant increase in calpain and caspase-3 activities, while the strongest effect was noted for BPAF. BPS, which is the main substituent of bisphenol A in polymers and thermal paper production exhibited similar eryptotic potential to BPA. Eryptotic changes in human erythrocytes were provoked by bisphenols at concentrations, which may influence the human body during occupational exposure or subacute poisoning with these compounds.

Bisphenol A and its analogs induce morphological and biochemical alterations in human peripheral blood mononuclear cells (in vitro study)

Few studies have addressed the cellular effects of bisphenol S (BPS) and bisphenol AF (BPAF) on cells, and no study has been conducted to analyze the mechanism of action of bisphenols in blood cells. In this study, the effect of bisphenol A (BPA), bisphenol F (BPF), BPS and BPAF on human peripheral blood mononuclear cells (PBMCs) was analyzed. It was shown that BPA, BPF and BPAF in particular, decreased cell viability, which was associated with depletion of intracellular ATP level and alterations in PBMCs size and granulation. Bisphenols enhanced ROS (including OH˙) formation, which led to damage to lipids and proteins in PBMCs. The most significant alterations in ROS level were induced by BPF, and particularly BPAF. Moreover, it was shown that BPAF most strongly provoked lipid peroxidation, while BPA and BPS caused the greatest damage to proteins. It may be concluded that BPA and its analogs were capable of inducing oxidative stress and damage in PBMCs in the concentrations ranging from 0.06 to 0.5 μM (0.02-0.1 μg/ml), which may be present in human blood as a result of environmental exposure. Although, most of bisphenols studied decreased cell viability, size and ATP level at higher concentrations, BPAF exhibited its cytotoxic potential at low concentrations ranging from 0.3 to 3 μM (0.1-1.0 μg/ml) that may correspond to concentrations in humans following occupational exposure.

Bisphenol A, bisphenol S, bisphenol F and bisphenol AF induce different oxidative stress and damage in human red blood cells (in vitro study)

Bisphenol A (BPA) and its analogs are widely used in the production of various everyday use products, which leads to a common exposure of humans to these substances. The effect of bisphenols on oxidative stress parameters has not been described in detail in non-nucleated cells, therefore, we have decided to evaluate the impact of BPA and its analogs, i.e. bisphenol S (BPS), bisphenol F (BPF) and bisphenol AF (BPAF) on reactive oxygen species (ROS) formation, lipid peroxidation, glutathione (GSH) level and the activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) in human erythrocytes. The erythrocytes were incubated with the compounds studied in the concentrations ranging from 0.1 to 500μg/ml for 1, 4 or 24h. It has been found that bisphenols enhanced ROS (including •OH) formation, depleted GSH level, increased lipid peroxidation and changed the activities of SOD, CAT and GSH-Px. It has been noted that the strongest alterations in ROS formation, lipid peroxidation and the activity of antioxidant enzymes were induced by BPAF, which changed CAT and SOD activity even at 0.5μg/ml. It has also been shown that BPA caused the strongest changes in GSH level, while BPS, which is the main BPA substituent in the manufacture did not alter most parameters studied.

Protective activity of the Uncaria tomentosa extracts on human erythrocytes in oxidative stress induced by 2,4-dichlorophenol (2,4-DCP) and catechol

The purpose of this study was to evaluate the effect of the ethanolic and aqueous extracts of Uncaria tomentosa on human erythrocytes and additionally the assessment of protective effect of these extracts on hemolysis induction, hemoglobin oxidation, and changes in the level of reactive oxygen species (ROS) and lipid peroxidation, which were provoked by selected xenobiotics, i.e. 2,4-dichlorophenol (2,4-DCP) and catechol. All tested extracts, even at a very high concentration of 500 μg/ml were not toxic to the erythrocytes because they did not cause lipid peroxidation, increase methemoglobin and ROS levels nor provoked hemolysis. The results of this study also revealed protective effect of extracts of U. tomentosa. The extracts studied depleted the extent of hemoglobin oxidation and lipid peroxidation as well as decreased the level of ROS and hemolysis, which was provoked by 2,4-DCP. No protective activity of the extracts against catechol action, which is a precursor of semiquinones in cell was found. A difference in the effect of the extracts studied was observed. Ethanol-based extracts revealed more pronounced ability to inhibit oxidation processes in human erythrocytes.

Chlorophenols and chlorocatechols induce apoptosis in human lymphocytes (in vitro).

In this work the effect of 2,4,5-trichlorophenol (2,4,5-TCP), pentachlorophenol (PCP), 4,6-dichloroguaiacol (4,6-DCG), tetrachloroguaiacol (TeCG), 4,5-dichlorocatechol (4,5-DCC) and tetrachlorocatechol (TeCC) on the induction of apoptosis in human peripheral blood lymphocytes was examined. The analysis of the changes in mitochondrial transmembrane potential (DeltaPsi(m)) was performed using JC-9 fluorescent probe. It was noted that all the compounds studied (excluding 4,6-DCG) in a dose-dependent manner (0.2-25 ppm) increased the number of cells, which were characterized by the DeltaPsi(m) reduction, with the strongest effect observed for TeCG and TeCC. Moreover, fluorimetric assay of the caspase-3 activity revealed that 2,4,5-TCP, chlorocatechols and TeCG in the range of the concentrations of 1-50 ppm increased the caspase-3 expression, whereas PCP in its highest concentration of 50 ppm decreased the activity of this enzyme. It was also noted that the caspase-3 activity was the most strongly induced by tetrachlorocatechols, particularly by TeCC. The analysis of YO-PRO-1 iodide/propidum iodide staining revealed that TeCC, the most strongly increased the number of apoptotic cells at 5 and 25 ppm, whereas at a dose of 100 ppm the strongest effect on apoptosis induction was observed for 2,4,5-TCP.

Chlorophenols induce lipid peroxidation and change antioxidant parameters in the leaves of wheat (Triticum aestivum L.)

In this work, changes in superoxide dismutase (SOD), catalase (CAT) and guaiacol peroxidase (POD) activity were determined in the leaves of wheat (Triticum aestivum L.) exposed to 2,4-dichlorophenol (2,4-DCP) and pentachlorophenol (PCP). We analyzed the content of free phenols, the level of lipid peroxidation, and also the oxidation of dihydrorhodamine 123 by 2,4-DCP and PCP. Chlorophenols were spiked to soil in concentrations of 0.5 and 5.0 mg kg(-1). Plant seeds were raised in plastic pots containing soil at a temperature of 25 degrees C with a 16-h photoperiod and irradiance of 250 micromol m(-2) s(-1). The leaves were harvested on the third, sixth and twelfth days of the experiment. The inhibition of SOD activity in the leaves of wheat was observed for 2,4-DCP and PCP. 2,4-DCP and PCP induced changes in CAT activity with a stronger effect for PCP. The compounds markedly increased guaiacol POD activity during 12d of the exposition of wheat to their action. The increase in free phenol content was observed both for 2,4-DCP and PCP. Chlorophenols also induced a powerful lipid peroxidation process between the third and sixth days of the experiment. A higher concentration of chlorophenols used in our study induced greater changes in all of the investigated parameters. 2,4-DCP and PCP oxidized the fluorescent probe - dihydrorhodamine 123 - in the concentrations of 5 and 1 ppm, respectively, and the addition of magnesium ions enhanced the oxidative capacity of the examined xenobiotics.

Evaluation of the effect of Uncaria tomentosa extracts on the size and shape of human erythrocytes (in vitro)

In this study, we continued our investigations concerning the interaction of Uncaria tomentosa extracts with the human erythrocytes. The analysis of the size and shape of the erythrocytes by means of flow cytometry and phase contrast microscopy was performed. We executed our experiments using ethanolic and aqueous extracts from the leaves and bark of U. tomentosa. Disturbances were observed in the size and shape of the erythrocytes incubated with ethanolic and aqueous extracts at the concentrations of 100 μg/mL and 250 μg/mL, respectively. The observed changes were probably related to the entry of polyphenolic compounds contained in U. tomentosa extracts into erythrocyte membrane. Externalization of phosphatidylserine on the erythrocytic surfaces was also noticed during incubation with extracts at concentration of 250 μg/mL. We concluded that all of the extracts examined induced changes in the erythrocyte membrane properties, whereas ethanolic extracts from bark induced the most significant changes. The possible binding of polyphenols to the erythrocyte surface may have accounted for the protective properties of extracts against haemolysis of RBCs, which was observed in our previous study (Bors et al., 2011), but considerable incorporation of polyphenols into cell membranes can result in disturbance of phosphatidylserine transport and changes in erythrocyte shape. Nevertheless the results of the investigations showed that considerable morphological changes appear only as a result of erythrocyte exposure to high concentrations (50 ppm and 100 ppm) of the extracts studied, thus they should not lead to clinical erythrocytic damage if recommended doses of U. tomentosa preparations are administrated.

Bisphenol A and its analogs exhibit different apoptotic potential in peripheral blood mononuclear cells (in vitro study)

There are only a few studies that have assessed the effect of bisphenol A (BPA) on human blood cells and no study has been conducted to analyze the impact of BPA analogs on human leucocytes. In this study, we have investigated the effect of BPA and its analogs like bisphenol F (BPF), bisphenol S (BPS) and bisphenol AF (BPAF) on apoptosis induction in human peripheral blood mononuclear cells (PBMCs). In order to clarify the mechanism of bisphenols-induced programmed cell death, changes in various signaling molecules of this process have been assessed. We observed an increase in cytosolic calcium ions (Ca(2+)) level and reduction of transmembrane mitochondrial potential (ΔΨm) in PBMCs incubated with all compounds examined, and particularly BPA and BPAF. All compounds studied changed PBMCs membrane permeability, activated caspase-8, -9, -3 and induced PARP-1 cleavage and chromatin condensation, which confirmed that they were capable of inducing apoptosis both via intrinsic and extrinsic pathway. Moreover, we have found that modus operandi of bisphenols studied was different. We noticed that BPAF and BPS caused mainly necrotic and apoptotic changes, respectively, whereas BPA induced comparable apoptotic and necrotic effects in the incubated cells.

Comparative study of the effect of BPA and its selected analogues on hemoglobin oxidation, morphological alterations and hemolytic changes in human erythrocytes.

Bisphenol A (BPA) has been shown to provoke many deleterious impacts on human health, and thus it is now successively substituted by BPA analogues, whose effects have been poorly investigated. Up to now, only one study has been realized to assess the effect of BPA on human erythrocytes, which showed its significant hemolytic and oxidative potential. Moreover, no study has been conducted to evaluate the effect of BPA analogues on red blood cells. The purpose of the present study was to compare the impact of BPA and its selected analogues such as bisphenol F (BPF), bisphenol S (BPS) and bisphenol AF (BPAF) on hemolytic and morphological changes and hemoglobin oxidation (methemoglobin formation) of human erythrocytes. The erythrocytes were incubated with different bisphenols concentrations ranging from 0.5 to 500μg/ml for 1, 4 and 24h. The compounds examined caused hemolysis in human erythrocytes with BPAF exhibiting the strongest effect. All bisphenols examined caused methemoglobin formation with BPA inducing the strongest oxidative potential. Flow cytometry analysis showed that all bisphenols (excluding BPS) induced significant changes in erythrocytes size. Changes in red blood cells shape were conducted using phase contrast microscopy. It was noticed that BPA and BPAF induced echinocytosis, BPF caused stomatocytosis, while BPS did not provoke significant changes in shape of red blood cells. Generally, the results showed that BPS, which is the main substituent of bisphenol A in polymers and thermal paper production, exhibited significantly lower disturbance of erythrocyte functions than BPA.