Inflammation response and cytotoxic effects in human THP-1 cells of size-fractionated PM10 extracts in a polluted urban site

Biological effects of particulate matter samples during the COVID-19 pandemic: a comparison with the pre-lockdown period in Northwest Italy

In 2020, during the COVID-19 pandemic, containment measures were applied inducing potential changes in air pollutant concentrations and thus in air toxicity. This study evaluates the role of restrictions on biological effects of particulate matter (PM) in different Northwest Italy sites: urban background, urban traffic, rural, and incinerator. Daily PM samples collected in 2020 were pooled according to restrictions: January/February (no restrictions), March and April (first lockdown), May/June and July/August/September (low restrictions), October/November/December (second lockdown). The 2019 samples (pre-pandemic period) were pooled as 2020 for comparison. Pools were extracted with organic solvents and extracts were tested to assess cytotoxicity (WST-1 assay) and genotoxicity (comet assay) on BEAS-2B cells, mutagenicity (Ames test) on TA98 and TA100 Salmonella typhimurium strains, and estrogenic activity (gene reporter assay) on MELN cells. Pollutant concentrations were also analyzed (PM10, PM2.5, polycyclic aromatic hydrocarbons). No difference was observed for PM and polycyclic aromatic hydrocarbon concentrations between 2020 and 2019. During lockdown months (2020), PM cytotoxicity/genotoxicity was significantly lower in some sites than during 2019, while considering PM mutagenicity/estrogenic activity some differences were detected but without statistical significance. PM extract effects decreased in some sites during 2020; this may be due to lockdowns that reduced/modified pollutant emissions and may be related also to complex PM origin/formation and to meteorological conditions. In conclusion, the study confirms that PM biological effects cannot be assessed considering only the PM concentration and suggests to include a battery of bioassay for air quality monitoring in order to protect human health from air pollution effects.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s11869-023-01381-6.

Genotoxic effects of particulate matter on larvae of a common and widespread butterfly along an urbanization gradient

Biodiversity is currently declining worldwide. Several threats have been identified such as habitat loss and climate change. It is unknown if and how air pollution can work in addition or in synergy to these threats, contributing to the decline of current species and/or local extinction. Few studies have investigated the effects of particulate matter (PM), the main component of air pollution, on insects, and no studies have investigated its genotoxic effects through Micronucleus assay. Butterflies play an important role in the environment, as herbivores during larval stages, and as pollinators as adults. The aim of this study was to evaluate the genotoxic effects of PM₁₀ from different sites along a gradient of population urbanization, on a common cabbage butterfly species (Pieris brassicae). PM₁₀ was collected from April to September in an urban (Turin, Italy), a suburban (Druento, Italy) and a mountain site (Ceresole Reale, Italy) with different urbanization levels. P. brassicae larvae (n = 218) were reared in the laboratory under controlled conditions (26 °C, L:D 15:9) on cabbage plants (average 9.2 days), and they were exposed to PM₁₀ organic extracts (20 and 40 m³/mL) or dimethyl sulfoxide (controls) through vaporization. After exposure, larvae were dissected and cells were used for the Micronucleus (MN) assay. Results showed that all PM extracts induced significant DNA damage in exposed larvae compared to controls, and that increasing the PM dose (from 20 to 40 m³/mL) increased genotoxic effects. However, we did not detect any significant differences between sites with different urbanization levels. In conclusion, PM at different concentrations induced genotoxic effects on larvae of a common butterfly species. More alarmingly, PM could work in addition to and/or in synergy with other compounds (e.g. pesticides) and, especially on species already threatened by other factors (e.g. fragmentation), thus affecting the vitality of populations, leading to local extinctions.

Cabbage butterfly as bioindicator species to investigate the genotoxic effects of PM10

Atmospheric pollution poses a serious threat to environment and human health, and particulate matter (PM) is one of the major contributors. Biological effects induced by PM are investigated through in vitro assays using cells and by in vivo tests with laboratory model animals. However, also the estimation of adverse effects of pollutants, including airborne ones, on wild animals, such as insects, is an essential component of environmental risk assessment. Among insects, butterflies are sensitive to environmental changes and are important wild pollinators, so they might be suitable as environmental bioindicator species. The aim of this study was to evaluate the suitability of a wild cabbage butterfly species (Pieris brassicae) as a bioindicator organism to assess the genotoxic effects of PM₁₀ collected in different sites. PM₁₀ was collected from April to September in urban, suburban, and rural sites. P. brassicae larvae were reared in laboratory under controlled conditions on cabbage plants and exposed to PM₁₀ organic extracts or dimethyl sulfoxide (controls) through vaporization. After exposure, larvae were dissected, and cells were used for comet assay. All PM extracts induced significant DNA damage in exposed larvae compared to controls and the extract collected in the most polluted site caused the highest genotoxic effect. In conclusion, the study suggested that butterflies, such as P. brassicae, could be applied as sensitive and promising bioindicators to investigate air quality and PM genotoxicity. Indeed, the use of these organisms allows the detection of genotoxic effects induced by PM sampled also in low-polluted areas.

The North-western Italy air quality monitoring network: Improving experience of PM2.5 assessment with mutagenicity assay

The finest fraction of Particulate Matter (PM2.5) carries a large number of pollutants, some of which are assessed as genotoxic, such as some Polycyclic Aromatic Hydrocarbons (PAHs). In many countries, PM2.5 in combination with some PAHs are monitored to assess the concentrations of pollutants, while the air quality is rarely assessed by means of biological assays. Epidemiological studies have demonstrated a significant correlation between these two pollutants and human adverse effects, in particular on the respiratory system. Nevertheless, other air pollutants can induce a biological effect and the cumulative effect of the PM2.5 complex mixture may not be easily deduced by PM2.5 and PAH levels. This study aimed to combine the legislative monitoring of PM2.5 with the study of its mutagenicity. During a full year, daily air samples were collected in nine sites of the North-western Italy air quality monitoring network (Piedmont Region) and PM2.5 and PAH concentrations were assessed. Monthly pooled organic extracts were tested with the Salmonella assay using TA98 and TA100 strains, with and without metabolic activation (±S9), and using TA98NR and YG1021 strains. In all sites, a positive response was observed for TA98 and TA100 especially without S9. A significant mutagenic seasonal variation was detected, with higher mutagenicity in winter and lower responses in summer (average total mutagenicity ratio 27:1). The response of TA98NR and YG1021 compared with TA98 suggested a significant contribution of nitro-compounds to the mutagenicity. No significant differences were found between urban background and rural sites denoting the spread of pollution. A mutagenicity increase, 1.28 Total Mutagenicity Factor/20 m³, was observed for each PM2.5 μg increment. PAH levels and corresponding Toxic Equivalent Factors were highly correlated to mutagenicity results. This work confirms that complex environmental mixtures can be appropriately assessed through the implementation of physical-chemical analyzes with bioassays able to evaluate synergistic and antagonistic effects, especially for highest and lowest pollution settings.

Attenuation effect of polydeoxyribonucleotide on inflammatory cytokines and apoptotic factors induced by particulate matter (PM10) damage in human bronchial cells

Particulate matter (PM) of 10-μm-sized fine dust in the air penetrates the respiratory tract and contributes to the increasing incidence of various lung diseases, but its definite mechanism is not known. Recently, polydeoxyribonucleotide (PDRN) has been shown to have anti-inflammatory and regenerative effects in various tissues. However, the bronchial-related mechanism is not well-understood. Hence, this experiment is intended to demonstrate the beneficial effect of PDRN administration on PM10-induced injury in human bronchial-derived NCI-H358 cells. To confirm the protective effect of PDRN, PM10 was applied after PDRN pretreatment to confirm changes in NCI-H358 cells. Experiments were conducted to measure cell survival, cytotoxicity, inflammation, and apoptotic factor changes. WST-8 assay was used to confirm cell viability, and lactate dehydrogenase assay was used to obtain cytotoxicity. In addition, changes in inflammatory cytokines and apoptotic factors were confirmed by enzyme-linked immunosorbent assay and Western blot. Decreased cell viability and increased cytotoxicity, inflammatory cytokines, and apoptotic factors were observed after exposure to PM10. However, pretreatment with PDRN enhanced cell viability and reduced cytotoxicity. In addition, the expression of inflammatory cytokines such as tumor necrosis factor-α, interleukin-6 (IL-6), and IL-1β, and cell death factors such as Apaf-1, cyt c, caspase-3, caspase-9, Bid, and Bax/Bcl-2 ratio were decreased by PDRN administration in PM10-exposed NCI-H358 cells. PDRN, an A2AR agonist, affects cAMP activation and regulation of phosphorylation of PKA and CREB. In addition, treatment with A2AR antagonist 3,7-dimethyl-1-propargylxanthine significantly blocked PDRN's effect. These anti-cytotoxicity, anti-inflammation, and anti-apoptosis effects of PDRN can be attributed to the adenosine A2AR enhancing effect on PM10-exposed bronchial cells.

Fifteen Years of Airborne Particulates in Vitro Toxicology in Milano: Lessons and Perspectives Learned

Air pollution is one of the world’s leading environmental causes of death. The epidemiological relationship between outdoor air pollution and the onset of health diseases associated with death is now well established. Relevant toxicological proofs are now dissecting the molecular processes that cause inflammation, reactive species generation, and DNA damage. In addition, new data are pointing out the role of airborne particulates in the modulation of genes and microRNAs potentially involved in the onset of human diseases. In the present review we collect the relevant findings on airborne particulates of one of the biggest hot spots of air pollution in Europe (i.e., the Po Valley), in the largest urban area of this region, Milan. The different aerodynamic fractions are discussed separately with a specific focus on fine and ultrafine particles that are now the main focus of several studies. Results are compared with more recent international findings. Possible future perspectives of research are proposed to create a new discussion among scientists working on the toxicological effects of airborne particles.

Micronucleus Frequency in Exfoliated Buccal Cells of Children Living in an Industrialized Area of Apulia (Italy)

Micronuclei (MN) are biomarkers of early biological effect often used for detecting DNA damage in human population exposed to genotoxic agents. The aim of this study was to evaluate the frequency of MN in exfoliated buccal cells of children living in an industrialized (impacted) area compared with that found in children living in a control area without significant anthropogenic impacts. A total of 462 6–8-year-old children (206 in the impacted area, 256 in the control area) attending primary school were enrolled. A questionnaire was administered to the parents of the recruited children to obtain information about personal data, lifestyles, and food habits of their children. Atmospheric particulate fractions were collected near the involved schools to assess the level of environmental exposure of the children. The presence of MN was highlighted in 68.4% of children living in the impacted area with a mean MN frequency of 0.66‰ ± 0.61‰. MN positivity and frequency were significantly lower in the control area (37.1% and 0.27‰ ± 0.43‰, respectively). The frequency of MN was positively associated with quasi-ultrafine particulate matter (PM_0.5), traffic near the home, and consuming barbecued food; while adherence to the Mediterranean diet and practicing sport were negatively associated.

Airborne Particulate Matter: Human Exposure and Health Effects

OBJECTIVE

Exposure to airborne particulate matter (PM) is estimated to cause millions of premature deaths annually. This work conveys known routes of exposure to PM and resultant health effects.

METHODS

A review of available literature.

RESULTS

Estimates for daily PM exposure are provided. Known mechanisms by which insoluble particles are transported and removed from the body are discussed. Biological effects of PM, including immune response, cytotoxicity, and mutagenicity, are reported. Epidemiological studies that outline the systemic health effects of PM are presented.

CONCLUSION

While the integrated, per capita, exposure of PM for a large fraction of the first-world may be less than 1 mg per day, links between several syndromes, including attention deficit hyperactivity disorder (ADHD), autism, loss of cognitive function, anxiety, asthma, chronic obstructive pulmonary disease (COPD), hypertension, stroke, and PM exposure have been suggested. This article reviews and summarizes such links reported in the literature.

Chemical and organic characteristics of PM2.5 particles and their in-vitro cytotoxic effects on lung cells: The Middle East dust storms in Ahvaz, Iran

There are very few reports about the effect of PM_2.5 particles carried by the Middle East dust storms on lung cells. This study aimed to investigate the chemical properties and in-vitro cytotoxic effects of PM_2.5 extracts. Water-soluble fraction and organic solvent-extractable components of the samples collected from the city of Ahvaz, Khuzestan Province, Iran, during the normal and dust storm days of the winter of 2016 were analyzed and then applied on the human lung epithelial cell line (A549). The chemical properties and the cytotoxicity were analyzed by ICP-OES and Lactase Dehydrogenase (LDH) assay, respectively. The results of the independent t-test showed significantly higher mean cytotoxicity in the samples of normal days than that of dust storm days. It could be due to the fact that the cells were exposed to the same amount of water-soluble extract, whether it be from a normal day or a dust storm day, and since the normal air of Ahvaz is severely affected by traffic and industrial pollutants, its normal day samples showed stronger cytotoxic effect. The results of the Kruskal-Wallis test showed that cytotoxic effect increased with the particulate concentration. The highest cytotoxicity levels observed at 62, 125, and 250 μg/mL concentrations after 24-h incubation were 17% (belonging to a dust storm day), 37% (belonging to a normal day), and 47% (belonging to a dust storm day), respectively Since PAH compounds were measured in the particulate phase, their amount was naturally correlated with the quantity of particulates. However, it was observed that the samples of normal days contained the species with stronger human carcinogens ΣPAHs = 0.82 ng/m³.The results of one-way ANOVA showed a significant difference between the incubation times regarding the resulted cytotoxicity levels. In general, as the incubation duration increased, so did the cytotoxicity level. Although normal day particulates had a greater cytotoxic effect on A549 cell line, dust storm days are associated with higher levels of health risk; simply because during dust storms, people inhale much larger amounts of particulates.

Mutagenic and genotoxic effects induced by PM0.5 of different Italian towns in human cells and bacteria: The MAPEC_LIFE study

Particulate matter (PM) is considered an atmospheric pollutant that mostly affects human health. The finest fractions of PM (PM_2.5 or less) play a major role in causing chronic diseases. The aim of this study was to investigate the genotoxic effects of PM_0.5 collected in five Italian towns using different bioassays. The role of chemical composition on the genotoxicity induced was also evaluated. The present study was included in the multicentre MAPEC_LIFE project, which aimed to evaluate the associations between air pollution exposure and early biological effects in Italian children. PM₁₀ samples were collected in 2 seasons (winter and spring) using a high-volume multistage cascade impactor. The results showed that PM_0.5 represents a very high proportion of PM₁₀ (range 10-63%). PM_0.5 organic extracts were chemically analysed (PAH_s, nitro-PAH_s) and tested by the comet assay (A549 and BEAS-2B cells), MN test (A549 cells) and Ames test on Salmonella strains (TA100, TA98, TA98NR and YG1021). The highest concentrations of PAHs and nitro-PAHs in PM_0.5 were observed in the Torino, Brescia and Pisa samples in winter. The Ames test showed low mutagenic activity. The highest net revertants/m³ were observed in the Torino and Brescia samples (winter), and the mutagenic effect was associated with PM_0.5 (p < 0.01), PAH and nitro-PAH (p < 0.05) concentrations. The YG1021 strain showed the highest sensitivity to PM_0.5 samples. No genotoxic effect of PM_0.5 extracts was observed using A549 cells except for some samples in winter (comet assay), while BEAS-2B cells showed light DNA damage in the Torino, Brescia and Pisa samples in winter, highlighting the higher sensitivity of BEAS-2B cells, which was consistent with the Ames test (p < 0.01). The results obtained showed that it is important to further investigate the finest fractions of PM, which represent a relevant percentage of PM₁₀, taking into account the chemical composition and the biological effects induced.

Is it the time to study air pollution effects under environmental conditions? A case study to support the shift of in vitro toxicology from the bench to the field

Air pollution and particulate matter are recognised cause of increased disease incidence in exposed population. The toxicological processes underlying air pollution associated effects have been investigated by in vivo and/or in vitro experimentation. The latter is usually performed by exposing cells cultured under submerged condition to particulate matter concentration quite far from environmental exposure expected in humans. Here we report for the first time the feasibility of a direct exposure of air liquid interface cultured cells to environmental concentration of particulate matter. Inflammatory proteins release was analysed in cell medium while differential expression of selected genes was analysed in cells. Significant association of anti-oxidant genes was observed with secondary and aged aerosol, while cytochrome activation with primary and PAHs enriched ultrafine particles. The results obtained clearly show the opportunity to move from the lab bench to the field for properly understanding the toxicological effects also of ultrafine particles on selected in vitro models.

Physical Activity, Lifestyle Factors and Oxidative Stress in Middle Age Healthy Subjects

Oxidative stress (OS) has been recognized to play a primary role in many acute and chronic diseases. Environmental and lifestyle factors, such as physical activity and dietary intake are involved in the oxidative balance, but their specific influence remains unclear. In order to contribute to a greater characterization of the oxidative status in relation to exercise training and to environmental and lifestyle factors, different biomarkers—pro-oxidant capacity (d-ROMs), anti-oxidant capacity (BAP), radical scavenging activity (DPPH) and DNA damage (8-OHdGuo)—were measured in biological samples of a group of healthy middle aged subjects. The evaluation of the investigated biomarkers highlighted a significant effect of exercise training on OS, measured as d-ROMs and 8OhdGuo, in subjects playing regular physical activity. An association of the OS status measured by DPPH and 8-OhdGuo with the condition of living in urban high traffic areas was also found. Otherwise dietary habits did not reveal any significant effect on OS levels by the investigated biomarkers. As a whole the results obtained in this investigation suggested that a correct lifestyle, with regular physical activity practice, contributes to control the OS status in middle age subjects.