Proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors, such as alirocumab and evolocumab, effectively reduce LDL-C levels, improve cardiovascular outcomes, and are well tolerated in the treatment of heterozygous familial hypercholesterolemia (HeFH). Oxidative stress, increased in HeFH, leads to DNA damage, LDL oxidation (ox-LDL), and reduced total plasma antioxidant capacity, which promotes the development of atherosclerosis. The aim of the study was to assess whether treatment with PCSK9 inhibitors reduces ox-LDL, anti-ox-LDL antibodies, oxidative stress, and DNA damage, including 8-OH-Gua levels. The study included 40 patients with HeFH diagnosed clinically or genetically, and 33 healthy volunteers at low cardiovascular risk as controls. Blood samples were collected from all participants for lipid profile, Lp(a), oxidative stress markers (ox-LDL, 8-OHdG, anti-oxLDL antibodies), total antioxidant capacity of plasma (TAC), and DNA damage status (using the comet assay with repair enzymes). The study showed that treatment with PCSK9 inhibitors (alirocumab or evolocumab) in HeFH patients significantly improved lipid profiles and reduced levels of oxidative stress markers such as 8-OHdG and ox-LDL, while increasing levels of anti-ox-LDL and TAC. This therapy also significantly reduced purine and pyrimidine DNA damage, although not to the level observed in the control group. The efficacy of reducing DNA damage was greater with alirocumab, which could be related to higher baseline levels of Lp(a) and oxidative damage in these patients. Treatment with PCSK9 inhibitors in HeFH patients reduces oxidative stress and DNA damage, indicating additional non-lipid benefits that support their use in preventing atherosclerotic complications.

Ethanol consumption can modify both drug exposure and drug response. However, the clinical relevance of these interactions depends strongly on the timing and pattern of alcohol intake, the affected pharmacological pathway, the dosage form and organ reserve. This review summarizes current evidence on ethanol-drug interactions, particularly human crossover studies, phenotyping studies, cohort analyses and appropriate case reports. It distinguishes acute ethanol-drug co-exposure, chronic alcohol exposure, drug use during early abstinence after chronic drinking, and pharmacotherapy in alcohol-associated liver disease. Key mechanisms include ADH- and ALDH-dependent ethanol oxidation, acetaldehyde formation, NADH/NAD+ redox shift, CYP2E1 induction, carboxylesterase 1 (CES1) modulation, altered intestinal and hepatic first-pass handling, dose dumping from susceptible modified-release products, changes in protein binding in alcohol-associated liver disease, and ALDH inhibition with acetaldehyde accumulation in disulfiram-like reactions. At the molecular level, ethanol may promote acetaldehyde adduct formation with proteins and DNA, CYP2E1-driven reactive oxygen species generation, redox stress, intestinal barrier injury, and CES1-dependent transesterification of selected ester drugs. Acute ethanol intake mainly increases pharmacodynamic toxicity and causes short-term pharmacokinetic disturbances, including enhanced central nervous system depression, delayed gastric emptying, impaired glucose and lactate handling and altered hemodynamic responses. In contrast, chronic exposure, early abstinence and alcohol-associated liver disease are more often associated with hepatic enzyme and transporter remodeling, altered protein binding, reduced hepatic or renal reserve, and greater susceptibility to drug-related organ injury. The highest-risk scenarios involve older adults, polypharmacy, alcohol-associated liver disease, dehydration or acute illness, early abstinence, and the concurrent use of central nervous system depressants, glucose-lowering drugs, NSAIDs, antihypertensives, renally eliminated drugs or warfarin. Hence, ethanol exposure should be treated as a dynamic, context-dependent modifier factor that can acutely exacerbate pharmacodynamic toxicity, alter selected pharmacokinetic pathways and lower organ tolerance to drug-related injury.

The widespread presence of polystyrene nanoparticles (PS-NPs) in the human body has raised concerns about their potential biological toxicity. When assessing the safety of nanoparticles and other xenobiotics, a key aspect is their effect on blood cells, particularly erythrocytes, which experience the most direct exposure to nanoparticles circulating in the bloodstream. The present study evaluated the impact of non-functionalized PS-NPs with diameters of ∼30 nm, ∼45 nm, and ∼70 nm on human red blood cells after 24 hours of incubation. The studied PS-NPs did not influence intracellular Ca2+ ion levels or caspase 3 activity, and did not induce phosphatidylserine translocation at pre-hemolytic concentrations (below 100 µg/mL). Moreover, exposure did not increase intracellular ROS levels at any of the tested concentrations, suggesting that generalized intracellular oxidative stress is likely not the primary mechanism underlying the effects induced by PS-NPs in human erythrocytes. However, the observed increase in lipid peroxidation, detected from 50 µg/ml, indicates that oxidative damage at the membrane level may contribute to the overall toxic response. The results suggest that PS-NPs interact primarily with the erythrocyte membrane, leading to membrane destabilization associated with increased calpain activity, observed already at a concentration of 1 µg/mL, and enhanced lipid peroxidation. It is noteworthy that the most pronounced changes were induced by the smallest nanoparticles (∼30 nm), suggesting a size-dependent effect on erythrocyte integrity. These findings suggest that PS-NP toxicity in erythrocytes is mediated mainly through red blood cell membrane destabilization rather than classical intracellular oxidative stress alone.

BACKGROUND/AIMS:Brominated flame retardants (BFRs) are widely used synthetic compounds with increasing environmental persistence and toxicological concern. This study investigated acetylcholinesterase (AChE) activity in human erythrocytes as a potential biomarker of BFR-induced cellular dysfunction. METHODS:AChE activity was measured spectrophotometrically using Ellman's method after exposure to selected compounds including tetrabromobisphenol A (TBBPA), tetrabromobisphenol S (TBBPS), and bromophenols. RESULTS:TBBPA and TBBPS significantly altered AChE activity, with increased enzyme activity observed at specific concentrations. Among bromophenols, significant effects were detected for 2,4,6-TBP and pentabromophenol. CONCLUSION:The biological effects of BFRs depend on chemical structure and concentration. While erythrocyte AChE responds to exposure, it is not a highly sensitive biosensor, as detectable changes occur alongside other cellular alterations.

Microplastics (MPs) and nanoplastics (NPs) are pervasive contaminants in the environment. Their presence, particularly in vulnerable populations such as infants, raises concerns about impact on human health. Therefore, this article aims to determine the exposure pathways, sources, and health consequences related to MPs and NPs exposure in infants (0–12 months of age). The conducted review indicates that the main exposure pathways of MPs and NPs in infants are inhalation and ingestion. The main dietary sources of MPs and NPs for children include plastic packaging, food preparation, and food products. The ingestion of these particles poses potential health risks, including physical, chemical, and biological effects. Microplastics and NPs can cross biological barriers, leading to systemic exposure and affecting infants’ development. The results obtained so far indicate a need for more comprehensive research to understand the extent of MPs and NPs contamination in infant diets and their long-term health implications.

Heterozygous familial hypercholesterolemia (HeFH) is a common autosomal dominant genetic disease (1:250) characterized by elevated LDL-C. Patients with HeFH are at increased risk of premature atherosclerosis and have at least a 10-fold greater chance of cardiovascular disease (CVD). The present study examines the effect of PCSK9 inhibitor treatment (iPCSK9: arilocumab or evolocumab) on DNA damage in HeFH patients. Fifty-six patients were studied, with a normolipidemic group (control; n = 20) and patients with HeFH (study group; n = 36). DNA damage was determined by alkaline comet assay and PCSK9 protein level by ELISA. PCSK9i treatment was found to be associated with lower DNA damage, Lp(a), PCSK9, and lipid profile compared to before treatment. However, 16 of 36 patients still had Lp(a) values above 125 nmol/L, and reduced Lp(a) did not correlate with reduced DNA damage. Reduced PCSK9 demonstrated a moderately positive correlation (r = 0.48) with reduced DNA damage. PCSK9i therapy reduces the level of DNA damage in HeFH patients, regardless of the type of inhibitor. While our findings confirm that PCSK9 treatment can reduce DNA damage, the mechanism remains unclear.

Bromophenols are aromatic compounds containing one or more benzene rings substituted with hydroxyl groups, bromine atoms, and other functional groups. Due to their widespread industrial use, bromophenols such as 2,4-dibromophenol (2,4-DBP), 2,4,6-tribromophenol (2,4,6-TBP) and pentabromophenol (PBP) have become prevalent environmental contaminants. These compounds are primarily found in air, water, and soil and bioaccumulate in various organisms, including fish and birds. Studies have linked bromophenols to oxidative stress, endocrine disruption, and adverse health effects, emphasizing the need to further investigate their biological impacts. Due to their high hydrophobicity and bioaccumulative potential, BPs may penetrate biological membranes, potentially altering their structural and functional properties. This study aimed to evaluate the impact of three bromophenols: 2,4-DBP, 2,4,6-TBP and PBP on erythrocyte membrane parameters and metabolic parameters such as ATP level. These findings highlight the differential effects of bromophenols on erythrocyte membranes, with 2,4-DBP primarily disrupting membrane fluidity and intracellular viscosity, while PBP predominantly affects oxidative processes. This study provides new insights into the potential toxicological mechanisms of BPs and their impact on cellular integrity. Moreover, the number of bromine atoms in bromophenols plays a crucial role in inducing damage to specific cellular structures and, ultimately, in determining their toxicity.

This study examined the profile of bioactive peptides and polysaccharides in beer wort enriched with malted and unmalted hemp seeds. The aim of this research was to evaluate the influence of different hemp processing methods (malted versus unmalted) on the concentration and characteristics of bioactive compounds—specifically (1) peptides exhibiting antioxidant, anti-inflammatory, and antihypertensive activities and (2) soluble polysaccharide fractions that affect wort viscosity and prebiotic potential. The results indicated that supplementation with 10% malted hemp seeds was most favorable. This level of addition enhanced the peptide composition of the wort without adversely affecting fermentation efficiency. Moreover, it facilitated the generation of functional peptides with antioxidant and flavor-enhancing properties and introduced non-fermentable polysaccharides that improved wort viscosity and foam stability without the negative effects observed at higher hemp seed concentrations. In contrast, a 30% addition of hemp seeds, particularly in unmalted form, led to a reduction in fermentable sugar and peptide contents and increased the likelihood of fermentation slowdown. The incorporation of 10% malted hemp seeds has the potential to enhance the sensory and functional attributes of beer, primarily due to the presence of bioactive peptides and polysaccharides, while maintaining fermentation performance and clarity. Fermentation and brewing efficiency may decline at higher hemp seed inclusion rates, warranting further investigation. The use of unmalted hemp necessitates enzymatic treatment to improve fermentable sugar availability. Additionally, high-performance size-exclusion chromatography (HPSEC) proved to be a valuable analytical tool for optimizing wort composition in the development of hemp-enriched beers.

The aim of the study was to determine the concentration- and size-dependent effects of ~30 nm, ~45 nm and ~70 nm non-functionalized polystyrene nanoparticles (PS-NPs) on human serum albumin (HSA) and human erythrocyte proteins in vitro. . HSA or human erythrocytes were exposed to PS-NPs at concentrations ranging from 0.001 to 100 µg/mL for 24 h. Any resulting changes in HSA secondary structure were investigated using circular dichroism (CD), fluorescence spectrum analysis, and fluorescence lifetime measurements. Incubation with 50 µg/mL and 100 µg/mL PS-NPs resulted in an increase in the hydrodynamic diameter of PS-NPs and caused significant alterations in HSA secondary structure for all tested nanoparticle sizes. Additionally, treatment with the ~30 nm and ~45 nm PS-NPs resulted in a more intense HSA fluorescence signal and changes in mean fluorescence lifetimes, indicating interactions between PS-NPs and HSA. Incubation with PS-NPs (0.1-1 µg/mL) also led to significant changes in relative viscosity and increased protein carbonyl content in erythrocytes (10-100 µg/mL); however, no significant changes in acetylcholinesterase (AChE) activity or methemoglobin levels were observed. The study confirms that non-functionalized polystyrene nanoparticles influence the structure and functional properties of human plasma and erythrocyte proteins under in vitro conditions, and their effects are clearly dependent on the size and concentration of the nanoparticles. It is likely that PS-NPs can modify the structure of albumin, which may indirectly potentiate plastic-related damage to erythrocytes in vivo. The potential influence of albumin modified by plastic particles on the properties of human erythrocytes in vivo was discussed.

The effect of non-functionalized polystyrene nanoparticles (PS-NPs) with diameters of 29, 44, and 72 nm on plasmid DNA integrity and the expression of genes involved in the architecture of chromatin was investigated in human peripheral blood mononuclear cells (PBMCs). The cells were incubated with PS-NPs at concentrations ranging from 0.001 to 100 µg/mL for 24 hours. Gene expression profiling was carried out using quantitative real-time PCR for the following genes: those involved in DNA methylation (DNMT1, DNMT3A), DNA demethylation (TET2, TET3), and chromatin remodeling, including histone methylation (EHMT1, EHMT2) and histone deacetylation (HDAC3, HDAC5). Furthermore, the expression of selected epigenetic markers related to histone acetylation and methylation (H3ac, H3K4me3, H3K9me3) at the protein level was examined using Western blotting. To assess the potential direct interaction of PS-NPs with DNA, a plasmid relaxation assay was performed in an extracellular system. The results demonstrated that PS-NPs do not cleave plasmid DNA directly. The gene expression analysis indicated that PS-NPs did not alter the expression of DNMT1, TET2, TET3, EHMT1, EHMT2, HDAC3, or HDAC5 in PBMCs. However, statistically significant changes in the expression of the DNMT3A gene were observed after exposure to 29 nm nanoparticles (p = 0.016, Kruskal-Wallis test), although post hoc comparisons did not reveal significant differences between individual treatment groups, and no clear dose-dependent trend was evident. PS-NPs induced a statistically significant decrease in post-translational histone modifications, specifically H3ac and H3K4me3. These findings suggest that PS-NPs may influence the epigenetic mechanisms involved in the regulation of chromatin architecture.

Food components and herbal substances can inhibit or enhance the therapeutic effects of drugs, thus influencing their efficacy and safety. As relatively little in known of these interactions, the aim of this review is to shed further light on the potentially dangerous influences that food and herbs may have on cytochrome P450 enzyme (CYP) and monoamine oxidase (MAO) activity in the first stage of drug biotransformation. The review includes documented cases in which such interactions have led to health complications in patients. For example, fruit juices, such as grapefruit juice, cranberry juice, and pomegranate juice, have been found to interact with drugs, and to particularly inhibit CYP450 activity, and commonly used herbs are known to inhibit (e.g., Astragalus membranous) or induce (e.g., Hypericum perforatum) CYP enzymes involved in drug metabolism. CYP is also induced by polycyclic aromatic hydrocarbons (PAHs), found in grilled meat and tobacco smoke. The paper also discusses the toxic effects of tyramine, present in inter alia blue cheese, resulting from interactions with MAO-metabolised drugs. Most importantly, while the quantity of food and herbs consumed plays a significant role in the described drug interactions, it is possible for toxic effects to be observed even after the consumption of relatively small amounts. Patients are encouraged to consult a healthcare provider about any potential drug interactions that may occur when starting a new medication.

The aim of the present study was to investigate the concentration- and size-dependent effects of non-functionalized polystyrene nanoparticles (PS-NPs) of varying diameters (29 nm, 44 nm, and 72 nm) on specific epigenetic modifications and gene expression profiles related to carcinogenesis in human peripheral blood mononuclear cells (PBMCs) in vitro. This in vitro human-cell-based model is used to investigate the epigenetic effect of various environmental xenobiotics. PBMCs were exposed to PS-NPs at concentrations ranging from 0.001 to 100 µg/mL for 24 h period. The analysis encompassed epigenetic DNA modifications, including levels of 5-methyl-2′-deoxycytidine (5-mdC) and 5-(hydroxymethyl)-2′-deoxycytidine (5-hmdC), as well as the levels of 2′-deoxyuridine (dU) and 5-(hydroxymethyl)-2′-deoxyuridine (5-hmdU) by mass spectrometry methods, methylation in the promoter regions of selected tumor suppressor genes TP53 (P53), CDKN2A (P16), and CDKN1A (P21) and proto-oncogenes (CCND1, BCL2, BCL6), along with the expression profile of the indicated genes by real-time PCR assays. The results obtained revealed no significant changes in global DNA methylation/demethylation levels in PBMCs after short-term exposure to non-functionalized PS-NPs. Furthermore, there were no changes observed in the level of dU, a product of cytosine deamination. However, the level of 5-hmdU, a product of both 5-hmdC deamination and thymine oxidation, was increased at the highest concentrations of larger PS-NPs (72 nm). None of the PS-NPs caused a change in the methylation pattern of the promoter regions of the TP53, CDKN2A, CDKN1A, CCND1, BCL2 and BCL6 genes. However, gene profiling indicated that PS-NPs with a diameter of 29 nm and 44 nm altered the expression of the TP53 gene. The smallest PS-NPs with a diameter of 29 nm increased the expression of the TP53 gene at a concentration of 10 µg/mL, while PS-NPs with a diameter of 44 nm did so at a concentration of 100 µg/mL. An increase in the expression of the CDKN2A gene was also observed when PBMCs were exposed to PS-NPs with 29 nm in diameter at the highest concentration. The observed effect depended on both the concentration and the size of the PS-NPs.

Ecosystems worldwide are struggling with increasingly high levels of human-induced stressors, impacting their ecological health at local, regional, and global scales. Among the factors affecting freshwater organisms, temperature stands out, especially given the recent escalation of global warming, with possible adverse effects. In this study, we examined the basal levels of oxidative stress parameters in the round goby Neogobius melanostomus, spanning its native and non-native ranges of occurrence. We aimed to assess five populations across transcontinental scale (Turkey, Croatia, Slovakia, Poland, Finland) to determine whether individuals already experiencing conditions other than their thermal optimum (such as those in Turkey and Finland) would display elevated non-enzymatic indicators (level of lipid peroxidation and reduced glutathione levels) and enzymatic indicators (activity of glutathione peroxidase and catalase activity) of oxidative stress compared to those inhabiting milder ecosystems. The results obtained did not align with our initial predictions. The native Turkish population exhibited the lowest values for both antioxidants and oxidative damage, indicating an efficient redox system in this species. All tested parameters showed variation among populations, as well as between tissues and sexes. Temperature did not emerge as significant factor in any of the parameters tested, while for glutathione peroxidase, our analysis indicated a positive relationship with enzyme activity and salinity. The lack of a continuous latitudinal pattern in the non-native populations suggests the species’ potential for adaptive shifts, indicating superior adaptive abilities, especially in human affected ecosystems, rather than strictly adhering to environmental gradients.

Heterozygous familial hypercholesterolemia (HeFH) is a common autosomal-dominant inherited disorder associated with atherosclerotic cardiovascular disease (ASCVD). HeFH subjects have a higher lipoprotein(a), i.e. Lp(a), concentration than the general population. Patients with FH are exposed to elevated levels of LDL from birth and ox-LDL may induce other oxidation pathways. The aim of the study was to determine the levels of markers of oxidative stress and DNA damage in patients with HeFH and describe the effect of Lp(a) on the resulting damage. Higher DNA damage was identified in patients with HeFH compared to the normolipidemic ones, and ASCVD was associated with greater damage. Oxidative stress markers were elevated in HeFH patients; however, only ox-LDL was higher in the ASCVD group and its level correlated with DNA damage. A positive correlation was found between DNA damage and Lp(a) concentration in the HeFH patients. Higher levels of Lp(a) were associated with greater DNA damage, especially in patients with HeFH and ASCVD. In HeFH patients, the optimal Lp(a) cut-off point associated with ASCVD is > 23.45 nmol/L, i.e. much lower than for the general population; however this cut-off point needs validation in a larger group of HeFH patients.

Cannabis sativa L. contains numerous compounds with antioxidant and anti-inflammatory properties, including the flavonoids and the cannabinoids, particularly Δ-9-tetrahydrocannabinol (THC) and cannabidiol (CBD). Cannabinoids have an effect on the endocannabinoid system (ECS), a cellular communication network, and are, hence, widely studied for medical applications. Epidiolex®, a 99% pure oral CBD extract, has been approved by the FDA for the treatment of epilepsy. Nabiximols (Sativex) is an oromucosal spray containing equal volume of THC and CBD, and it is commonly used as an add-on treatment for unresponsive spasticity in multiple sclerosis (MS) patients. Several in vitro and in vivo studies have also shown that cannabinoids can be used to treat various types of cancer, such as melanoma and brain glioblastoma; the first positive clinical trials on the anticancer effect of a THC:CBD blend with temozolomide (TMZ) in the treatment of highly invasive brain cancer are very promising. The cannabinoids exert their anticancer properties in in vitro investigations by the induction of cell death, mainly by apoptosis and cytotoxic autophagy, and the inhibition of cell proliferation. In several studies, cannabinoids have been found to induce tumor regression and inhibit angiogenic mechanisms in vitro and in vivo, as well as in two low-numbered epidemiological studies. They also exhibit antiviral effects by inhibiting ACE2 transcription, blocking viral replication and fusion, and acting as anti-inflammatory agents; indeed, prior CBD consumption (a study of 93,565 persons in Chicago) has also been associated with a much lower incidence of SARS-CoV-2 infections. It is postulated that cannabis extracts can be used in the treatment of many other diseases such as systemic lupus erythematosus, type 1 diabetes, or various types of neurological disorders, e.g., Alzheimer’s disease. The aim of this review is to outline the current state of knowledge regarding currently used medicinal preparations derived from C. sativa L. in the treatment of selected cancer and viral diseases, and to present the latest research on the potential applications of its secondary metabolites.

We have described the influence of selected factors that increase the toxicity of nanoplastics (NPs) and microplastics (MPs) with regard to cell viability, various types of cell death, reactive oxygen species (ROS) induction, and genotoxicity. These factors include plastic particle size (NPs/MPs), zeta potential, exposure time, concentration, functionalization, and the influence of environmental factors and cell type. Studies have unequivocally shown that smaller plastic particles are more cytotoxic, penetrate cells more easily, increase ROS formation, and induce oxidative damage to proteins, lipids, and DNA. The toxic effects also increase with concentration and incubation time. NPs with positive zeta potential are also more toxic than those with a negative zeta potential because the cells are negatively charged, inducing stronger interactions. The deleterious effects of NPs and MPs are increased by functionalization with anionic or carboxyl groups, due to greater interaction with cell membrane components. Cationic NPs/MPs are particularly toxic due to their greater cellular uptake and/or their effects on cells and lysosomal membranes. The effects of polystyrene (PS) vary from one cell type to another, and normal cells are more sensitive to NPs than cancerous ones. The toxicity of NPs/MPs can be enhanced by environmental factors, including UV radiation, as they cause the particles to shrink and change their shape, which is a particularly important consideration when working with environmentally-changed NPs/MPs. In summary, the cytotoxicity, oxidative properties, and genotoxicity of plastic particles depends on their concentration, duration of action, and cell type. Also, NPs/MPs with a smaller diameter and positive zeta potential, and those exposed to UV and functionalized with amino groups, demonstrate higher toxicity than larger, non-functionalized and environmentally-unchanged particles with a negative zeta potential.

The perfluoalkyl substance (PFASs) perfluorooctane sulfonate (PFOS) has been widely used in industry. However, PFOS is a persistent organic pollutant and has been gradually replaced by its short-chain analogs, perfluorohexane sulfonate (PFHxS) and perfluorobutane sulfonate (PFBS). PFASs are extremely persistent and are very frequently detected among the general population.The aim of the study was to determine the effect of selected PFASs on peripheral blood mononuclear cells (PBMCs) and the mechanisms of their action. PBMCs were exposed to PFOS, PFBS and PFHxS at concentrations ranging from 0.02 to 400 μM for 24 h, they were then tested for viability, apoptosis (changes in cytosolic calcium ions level and caspase-3, -8 and -9 activation), ferroptosis (changes in chelatable iron ions level and lipid peroxidation), and autophagy (LC3-II and Raptor level assay).PFOS exposure decreased cell viability, increased calcium ion level and caspase-8 activation; it also enhanced lipid peroxidation and increased the intracellular pool of chelatable iron ions as well as LC3-II protein content. In contrast, short-chain PFBS and PFHxS induced significant changes in the markers of apoptosis but had no substantial impact on ferroptosis or autophagy markers over a wide range of concentrations.Our results indicate that only PFOS demonstrated pro-ferroptotic and pro-autophagic potential but observed changes occurred at relatively high exposure. A short-chain substitute (PFBS) exhibited strong pro-apoptotic potential at concentrations related to occupational exposure. While the short-chain PFASs strongly affected the mitochondrial pathway of apoptosis, apoptosis itself was only induced by PFBS via the intrinsic and extrinsic pathways.It seems that the length of the carbon chain in PFASs appears to determine the cell death mechanisms activated in human PBMCs following exposure. Our findings provide a new insight into the immune toxicity mechanism induced by these compounds.

Particles of various types of plastics, including polystyrene nanoparticles (PS-NPs), have been determined in human blood, placenta, and lungs. These findings suggest a potential detrimental effect of PS-NPs on bloodstream cells. The purpose of this study was to assess the mechanism underlying PS-NPs-induced apoptosis in human peripheral blood mononuclear cells (PBMCs). Non-functionalized PS-NPs of three diameters: 29 nm, 44 nm, and 72 nm were studied used in this research. PBMCs were isolated from human leukocyte–platelet buffy coat and treated with PS-NPs at concentrations ranging from 0.001 to 200 μg/mL for 24 h. Apoptotic mechanism of action was evaluated by determining the level of cytosolic calcium ions, as well as mitochondrial transmembrane potential, and ATP levels. Furthermore, detection of caspase-8, -9, and -3 activation, as well as mTOR level was conducted. The presence of apoptotic PBMCs was confirmed by the method of double staining of the cells with propidium iodide and FITC-conjugated Annexin V. We found that all tested NPs increased calcium ion and depleted mitochondrial transmembrane potential levels. The tested NPs also activated caspase-9 and caspase-3, and the smallest NPs of 29 nm of diameter also activated caspase-8. The results clearly showed that apoptotic changes and an increase of mTOR level depended on the size of the tested NPs, while the smallest particles caused the greatest alterations. PS-NPs of 26 nm of diameter activated the extrinsic pathway (increased caspase-8 activity), as well as intrinsic (mitochondrial) pathway (increased caspase-9 activity, raised calcium ion level, and decreased transmembrane mitochondrial potential) of apoptosis. All PS-NPs increased mTOR level at the concentrations smaller than those that induced apoptosis and its level returned to control value when the process of apoptosis escalated.