Chronic environmentally relevant levels of simvastatin disrupt embryonic development, biochemical and molecular responses in zebrafish (Danio rerio)

Energy metabolism disturbance induced by atorvastatin exposure on yellowstripe goby (Mugilogobius chulae) larvae based on transcriptome and metabolome analysis

Atorvastatin (ATV), a commonly prescribed lipid-lowering drug, has been widely detected in various aquatic environments due to its large use and low degradation rate. Since the target gene inhibited by ATV is highly conserved in organisms, many studies have shown that ATV can interfere with lipid metabolism in aquatic non-target organisms. However, studies on mitochondria, energy metabolism, and developmental toxicity of ATV on non-target organisms are limited. In this study, Mugilogobius chulae embryos were exposed to ATV (0.5 and 50 µg/L) until 96 hour post fertilization (hpf). The results confirmed that the environmental concentrations of ATV caused toxic effects including developmental malformations, pathological damage, hepatotoxicity, and oxidative stress in M. chulae larvae. Both transcriptomic and metabolomic analyses showed that ATV exposure interfered the normal processes of oxidative phosphorylation and TCA cycle, resulting in energy metabolic disorder. In addition, ATV exposure also damaged the mitochondrial structure of M. chulae larvae. Thus, M. chulae could regulate PI3K/AMPK/FoxO proteins to promote mitochondrial regeneration, support autophagy, and even initiate apoptosis to maintain metabolism homeostasis. Taken together, our findings suggested that mitochondrial dysfunction and metabolic disorder were involved in ATV-induced toxicity which may cause developmental malformations and abnormalities, providing novel insight into the toxic mechanisms of ATV.

Direct and transgenerational effects of simvastatin on the metabolism of the amphipod Gammarus locusta

In this study, untargeted Nuclear Magnetic Resonance (NMR) metabolomics was applied for the first time, to our knowledge, to assess the metabolic impact of direct and transgenerational exposure (F0 and F3 generations, respectively) of amphipods Gammarus locusta to simvastatin (SIM), a pharmaceutical widely prescribed for the treatment of hypercholesterolemia. Results revealed the important gender-dependent nature of each of these effects. Directly exposed males showed enhanced glucose catabolism and tricarboxylic acid (TCA) cycle activity, in tandem with adaptations in osmotic regulation and glyoxylate metabolism. Exposed females exhibited only a small osmoregulatory effect. It is suggested that the response of exposed males may reflect reported high levels of methyl farnesoate hormone (low levels in females) and alterations in apical factors, namely decreased growth. Conversely, transgenerational effects were identified only in females, with impact on energy metabolism (glycolysis and TCA cycle enhancement) and osmoregulatory response. This expresses the ability of female gametes to transmit the effects of direct SIM exposure. Such effects were putatively related to reported delayed maturation and transcriptomic deviations impacting on carbohydrate and lipid metabolisms, possibly specifically engaging phenylalanine/tyrosine and choline in dopamine and choline metabolisms. These findings reflect the importance of untargeted metabolomics in addressing not only direct exposure of contaminants, but also their transgenerational effects, potentially contributing towards improving hazard and risk assessment of biologically active compounds.

Are Environmental Levels of Nonsteroidal Anti-Inflammatory Drugs a Reason for Concern? Chronic Life-Cycle Effects of Naproxen in Zebrafish

The nonsteroidal anti-inflammatory drug naproxen (NPX) is among the most consumed pharmaceuticals worldwide, being detected in surface waters within the ng to μg/L range. Considering the limited chronic ecotoxicity data available for NPX in aquatic ecosystems, the present study aimed at evaluating its impact in the model organism Danio rerio, following a full life-cycle exposure to environmentally relevant concentrations (0.1 to 5.0 μg/L). An integration of apical endpoints, i.e., survival, growth, and reproduction, with gonad histopathology and gene transcription (RNA-seq) was performed to provide additional insights into the mode of action (MoA) of NPX. NPX decreased zebrafish growth and reproduction and led to histopathological alterations in gonads at concentrations as low as 0.1 μg/L. At the molecular level, 0.7 μg/L of NPX led to a disruption in gonads transcription of genes involved in several biological processes associated with reproduction, mainly involving steroid hormone biosynthesis and epigenetic/epitranscriptomic machineries. Collectively, these results show that environmentally realistic concentrations of NPX affect zebrafish reproduction and associated signaling pathways, indicating that current hazard and risk assessment data for NPX underestimate the environmental risk of this pharmaceutical.

Emergence of community behaviors in the gut microbiota upon drug treatment

Pharmaceuticals can directly inhibit the growth of gut bacteria, but the degree to which such interactions manifest in complex community settings is an open question. Here, we compared the effects of 30 drugs on a 32-species synthetic community with their effects on each community member in isolation. While most individual drug-species interactions remained the same in the community context, communal behaviors emerged in 26% of all tested cases. Cross-protection during which drug-sensitive species were protected in community was 6 times more frequent than cross-sensitization, the converse phenomenon. Cross-protection decreased and cross-sensitization increased at higher drug concentrations, suggesting that the resilience of microbial communities can collapse when perturbations get stronger. By metabolically profiling drug-treated communities, we showed that both drug biotransformation and bioaccumulation contribute mechanistically to communal protection. As a proof of principle, we molecularly dissected a prominent case: species expressing specific nitroreductases degraded niclosamide, thereby protecting both themselves and sensitive community members.

Reproductive toxicity and molecular responses induced by telmisartan in Daphnia magna at environmentally relevant concentrations

With aging population increasing globally, the use of pharmaceutically active compounds is rising. The cardiovascular drug telmisartan has been widely detected in various environmental compartments, including biota, surface waters, and sewage treatment plant effluents at concentrations ranging from ng/L to μg/L levels. This study evaluated the effects of telmisartan on the microcrustacean Daphnia magna at a wide range of concentrations (0.35, 0.70, 1.40, 500, and 1000 μg/L) and revealed significant ecotoxicological implications of this drug, even at environmentally relevant concentration. Acute exposure to telmisartan (1.40, 500, and 1000 μg/L) resulted in a notable decrease in heart rate, while chronic exposure accelerated the time to the first brood by 3 days and reduced neonate body size. Molecular investigations revealed marked downregulation of vitellogenin genes (Vtg1 and Vtg2). Non-monotonic dose responses were observed for gene expression, early-stage body length, and the total number of offspring produced, while the heart rate and time to the first brood showed clear concentration-dependent responses. These findings highlight the potential risks, notably to reproductive capacity, associated with exposure to telmisartan in environmentally relevant concentration, suggesting the need for further studies on the potential long-term ecological consequences.

Atorvastatin causes developmental and behavioral toxicity in yellowstripe goby (Mugilogobius chulae) embryos/larvae via disrupting lipid metabolism and autophagy processes

Atorvastatin (ATV) is one of the most commonly prescribed lipid-lowering drugs detected frequently in the environment due to its high use and low degradation rate. However, the toxic effects of residual ATV in the aquatic environment on non-target organisms and its toxic mechanisms are still largely unknown. In the present study, embryos of a native estuarine benthic fish, Mugilogobius chulae, were employed to investigate the developmental and behavioral toxic effects of ATV including environmentally relevant concentrations. The aim of this study was to provide a scientific basis for ecological risk assessment of ATV in the aquatic environment by investigating the changes of biological endpoints at multiple levels in M. chulae embryos/larvae. The results showed that ATV had significantly lethal and teratogenic effects on M. chulae embryos/larvae and caused abnormal changes in developmental parameters including hatch rate, body length, heart rate, and spontaneous movement. ATV exposure caused oxidative stress in M. chulae embryos/larvae subsequently inhibited autophagy and activated apoptosis, leading to abnormal developmental processes and behavioral changes in M. chulae embryos/larvae. The disruptions of lipid metabolism, autophagy, and apoptosis in M. chulae embryos/larvae caused by ATV exposure may pose a potential ecological risk at the population level.

ToF-SIMS imaging shows specific lipophilic vitamin alterations in chronic reprotoxicity caused by the emerging contaminant Pravastatin in Gammarus fossarum

Blood lipid-lowering agents, such as Pravastatin, are among the most frequently used pharmaceuticals released into the aquatic environment. Although their effects on humans are very well understood, their consequences on freshwater organisms are not well known, especially in chronic exposure conditions. Gammarus fossarum is commonly used as sentinel species in ecotoxicology because of its sensitivity to a wide range of environmental contaminants and the availability of standardized bioassays. Moreover, there is an increased interest in linking molecular changes in sentinel species, such as gammarids, to observed toxic effects. Here, we performed a reproductive toxicity assay on females exposed to different concentrations of pravastatin (30; 300; 3,000 and 30,000 ng L-1) during two successive reproductive cycles and we applied ToF-SIMS imaging to evaluate the effect of pravastatin on lipid homeostasis in gammarids. Reproductive bioassay showed that pravastatin could affect oocyte development in Gammarus fossarum inducing embryotoxicity in the second reproductive cycle. Mass spectrometry imaging highlighted the disruption in vitamin E production in the oocytes of exposed female gammarids at the second reproductive cycle, while limited alterations were observed in other lipid classes, regarding both production and tissue distribution. The results demonstrated the interest of applying spatially resolved lipidomics by mass spectrometry imaging to assess the molecular effects induced by long-term exposure to environmental pharmaceutical residues in sentinel species.

Early statin exposure influences cardiac and skeletal development with implications for ion channel transcriptomes in zebrafish

Statins, widely prescribed for cholesterol management by inhibiting HMG-CoA reductase in the cholesterol biosynthesis pathway, may also influence vertebrate development. In this study, we investigated the developmental effects of two widely used statins, atorvastatin (ATO) and pravastatin (PRA), on zebrafish offspring. For ATO, we administered doses classified as low (1 μM), medium (5 μM), and high (10 μM), while for PRA, the corresponding concentrations were set at low (18 μM), medium (180 μM), and high (270 μM). Our results showed significant reductions in birth and hatching rates, along with decreased body length in offspring at all ATO concentrations and medium to high PRA concentrations. A notable increase in malformation rates, especially in the spine and heart, was observed across all ATO treatments and in medium and high PRA groups. Additionally, we observed reduced heart contraction rates, decreased heart size, lower bone volumes, and diminished expression of mRNA osteogenic markers. Elevated venous sinus-artery bulb (SV-BA) ratios, increased thoracic area, and abnormal cartilage development were also prominent in all ATO-treated groups. Transcriptome analysis revealed alterations in genes predominantly associated with ion channels. These findings provide insights into the potential impacts of specific concentrations of statins on offspring development and highlight potential gene interactions with statins.

6-benzylaminopurine causes endothelial dysfunctions to human umbilical vein endothelial cells and exacerbates atorvastatin-induced cerebral hemorrhage in zebrafish

6-benzylaminopurine (6-BA), a multifunctional plant growth regulator, which is frequently used worldwide to improve qualities of various crops, is an important ingredient in production of "toxic bean sprouts." Although there is no direct evidence of adverse effects, its hazardous effects, as well as joint toxicity with other chemicals, have received particular attention and aroused furious debate between proponents and environmental regulators. By use of human umbilical vein endothelial cells (HUVECs), adverse effects of 6-BA to human-derived cells were first demonstrated in this study. A total of 25-50 mg 6-BA/L inhibited proliferation, migration, and formation of tubular-like structures by 50% in vitro. Results of Western blot analyses revealed that exposure to 6-BA differentially modulated the MAPK signal transduction pathway in HUVECs. Specifically, 6-BA decreased phosphorylation of MEK and ERK, but increased phosphorylation of JNK and P38. In addition, 6-BA exacerbated atorvastatin-induced cerebral hemorrhage via increasing hemorrhagic occurrence by 60% and areas by 4 times in zebrafish larvae. In summary, 6-BA elicited toxicity to the endothelial system of HUVECs and zebrafish. This was due, at least in part, to discoordination of MAPK signaling pathway, which should pose potential risks to the cerebral vascular system.

Fish as models to study liver and blood lipid-related effects of fibrates and statins and screen new hypolipidemic drugs

Fibrates and statins lead worldwide prescriptions of lipid-lowering drugs, whose consumption is increasing considerably due to the growing incidence of dyslipidemias, particularly in high-income areas. Consequently, these chemicals are frequently found in aquatic environments, usually closer to highly urbanized and populated areas, reaching the water systems primarily through waste-water treatment plant (WWTP) effluents. Despite that, the knowledge regarding the effects caused by fibrates and statins in fish, namely in liver lipid metabolism and blood-related parameters, is still very limited. There is yet no standardized fish model for testing the effects of those drugs. However, experimental evidence suggests that the mechanisms of action (MoA) of fibrates and statins are fairly similar to those observed in humans, which makes these aquatic organisms viable alternatives for toxicological and mechanistic studies. This graphical review serves as a state point regarding the potential use of fish as a model for the study of hypolipidemic compounds, addressing (I) the current state of aquatic pollution caused by statins and fibrates, (II) the experimental designs used in the literature to assess effects on fish, (III) the liver metabolism and blood effects caused by exposure to fibrates and statins, as well as (IV) the MoA of both drugs. It further focuses on the current and future benefits of establishing a standardized fish model(s) for testing hypolipidemic drugs.

Uptake of Nanoplastic particles by zebrafish embryos triggers the macrophage response at early developmental stage

Plastic pollution continues to erupt as a global ecological concern. As plastic debris is degraded into nanoscale and microscale particles via biodegradation, UV-irradiation, and mechanical processes, nanoplastic pollution arises as a threat to virtually every biological and ecological system on the planet. In this study, zebrafish (Danio rerio) embryos were exposed to fluorescently labeled plastic particles at nanoscales (30 nm and 100 nm). The uptake of both the nanoplastic particles (NPs) was found to exponentially increase with incubation time. Penetration of NPs through the natural barrier of the zebrafish embryos, the chorion, was observed prior to the hatching of the embryo. As a result, the NPs were found to accumulate on the body surface as well as inside the body of the zebrafish. The invasion of NPs into zebrafish embryos induced the upregulation of several stress and immune response genes including interleukins (il6 and il1b), cytochrome P450 (cyp1a and cyp51), and reactive oxygen species (ROS) removal protein-encoding genes (sod and cat). This suggested the initiation of ROS generation and removal as well as the activation of the immune response of zebrafish embryos. Colocalization of macrophages and NPs in zebrafish embryos indicated the involvement of macrophage response to the NP invasion at the early developmental stage of zebrafish.

Elucidating the Effects of the Lipids Regulators Fibrates and Statins on the Health Status of Finfish Species: A Review

The most documented fibrates are gemfibrozil, clofibrate and bezafibrate, while for statins, the majority of the published literature focuses on atorvastatin and simvastatin. The present work reviews previously published research concerning the effects of these hypocholesterolaemic pharmaceuticals on fish, with a particular focus on commercially important species, commonly produced by the European aquaculture industry, specifically in recirculated aquaculture systems (RAS). Overall, results suggest that both acute and chronic exposures to lipid-lowering compounds may have adverse effects on fish, disrupting their capacity to excrete exogenous substances, as well as both lipid metabolism and homeostasis, causing severe ontogenetic and endocrinological abnormalities, leading to hampered reproductive success (e.g., gametogenesis, fecundity), and skeletal or muscular malformations, having serious repercussions on fish health and welfare. Nonetheless, the available literature focusing on the effects of statins or fibrates on commonly farmed fish is still limited, and further research is required to understand the implications of this matter on aquaculture production, global food security and, ultimately, human health.

Using zebrafish embryo bioassays to identify chemicals modulating the regulation of the epigenome: a case study with simvastatin

Contaminants of emerging concern have been increasingly associated with the modulation of the epigenome, leading to potentially inherited and persistent impacts on apical endpoints. Here, we address the performance of the OECD Test No. 236 FET (fish embryo acute toxicity) in the identification of chemicals able to modulate the epigenome. Using zebrafish (Danio rerio) embryos, acute and chronic exposures were performed with the pharmaceutical, simvastatin (SIM), a widely prescribed hypocholesterolemic drug reported to induce inter and transgenerational effects. In the present study, the epigenetic effects of environmentally relevant concentrations of SIM (from 8 ng/L to 2000 ng/L) were addressed following (1) an acute embryo assay based on OECD Test No. 236 FET, (2) a chronic partial life-cycle exposure using adult zebrafish (90 days), and (3) F1 embryos obtained from parental exposed animals. Simvastatin induced significant effects in gene expression of key epigenetic biomarkers (DNA methylation and histone acetylation/deacetylation) in the gonads of exposed adult zebrafish and in 80 hpf zebrafish embryos (acute and chronic parental intergenerational exposure), albeit with distinct effect profiles between biological samples. In the chronic exposure, SIM impacted particularly DNA methyltransferase genes in males and female gonads, whereas in F1 embryos SIM affected mostly genes associated with histone acetylation/deacetylation. In the embryo acute direct exposure, SIM modulated the expression of both genes involved in DNA methylation and histone deacetylase. These findings further support the use of epigenetic biomarkers in zebrafish embryos in a high throughput approach to identify and prioritize epigenome-modulating chemicals.

Metformin disrupts Danio rerio metabolism at environmentally relevant concentrations: A full life-cycle study

Metformin (MET), an anti-diabetic pharmaceutical of large-scale consumption, is increasingly detected in surface waters. However, current knowledge on the long-term effects of MET on non-target organisms is limited. The present study aimed to investigate the effects of MET in the model freshwater teleost Danio rerio, following a full life-cycle exposure to environmentally relevant concentrations (390 to 14 423 ng/L). Considering that the mode of action (MoA) of MET on non-target organisms remains underexplored and that MET may act through similar human pathways, i.e., lipid and energy metabolisms, biochemical markers were used to determine cholesterol and triglycerides levels, as well as mitochondrial complex I activity in zebrafish liver. Also, the hepatosomatic index as an indication of metabolic disruption, and the expression levels of genes involved in MET's putative MoA, i.e. acaca, acadm, cox5aa, idh3a, hmgcra, prkaa1, were determined, the last by qRT-PCR. A screening of mRNA transcripts, associated with lipid and energy metabolisms, and other signaling pathways potentially involved in MET-induced toxicity were also assessed using an exploratory RNA-seq analysis. The findings here reported indicate that MET significantly disrupted critical biochemical and molecular processes involved in zebrafish metabolism, such as cholesterol and fatty acid biosynthesis, mitochondrial electron transport chain and tricarboxylic acid cycle, concomitantly to changes on the hepatosomatic index. Likewise, MET impacted other relevant pathways mainly associated with cell cycle, DNA repair and steroid hormone biosynthesis, here reported for the first time in a non-target aquatic organism. Non-monotonic dose response curves were frequently detected in biochemical and qRT-PCR data, with higher effects observed at 390 and 2 929 ng/L MET treatments. Collectively, the results suggest that environmentally relevant concentrations of MET severely disrupt D. rerio metabolism and other important biological processes, supporting the need to revise the proposed environmental quality standard (EQS) and predicted no-effect concentration (PNEC) for MET.

Exposure of zebrafish larvae to water accommodated fractions of weathered crude oil alters steroid hormone concentrations with minimal effect on cholesterol

Crude oil has multiple toxic effects in fish, particularly during their early life stages. Recent transcriptomics studies have highlighted a potential effect on cholesterol homeostasis and biosynthesis, but have not investigated effects on steroid hormones, which are biosynthetically downstream metabolites of cholesterol. We exposed zebrafish (Danio rerio) embryos and larvae to 3 concentrations of a high energy water accommodated fraction (HEWAF) of crude oil and measured effects on cholesterol and steroid hormones at 48 and 96 h post fertilization (hpf). HEWAF exposure caused a small decrease in cholesterol at 96 hpf but not 48 hpf. HEWAF-exposed larvae had higher levels of androstenedione, testosterone, estradiol, cortisol, corticosterone, and progesterone at 96 hpf compared to controls, while effects at 48 hpf were more modest or not present. 2-Methoxyestradiol was lower following HEWAF exposure at both time points. Dihydrotestosterone was elevated in one HEWAF concentration at 48 hpf only. Our results suggest that hormone imbalance may be an important toxic effect of oil HEWAF exposure despite no major effect on their biosynthetic precursor cholesterol.

Pharmaceutical Compounds in Aquatic Environments-Occurrence, Fate and Bioremediation Prospective

Various contaminants of emerging concern (CECs) have been detected in different ecosystems, posing a threat to living organisms and the environment. Pharmaceuticals are among the many CECs that enter the environment through different pathways, with wastewater treatment plants being the main input of these pollutants. Several technologies for the removal of these pollutants have been developed through the years, but there is still a lack of sustainable technologies suitable for being applied in natural environments. In this regard, solutions based on natural biological processes are attractive for the recovery of contaminated environments. Bioremediation is one of these natural-based solutions and takes advantage of the capacity of microorganisms to degrade different organic pollutants. Degradation of pollutants by native microorganisms is already known to be an important detoxification mechanism that is involved in natural attenuation processes that occur in the environment. Thus, bioremediation technologies based on the selection of natural degrading bacteria seem to be a promising clean-up technology suitable for application in natural environments. In this review, an overview of the occurrence and fate of pharmaceuticals is carried out, in which bioremediation tools are explored for the removal of these pollutants from impacted environments.

Zebrafish as a Model for the Study of Lipid-Lowering Drug-Induced Myopathies

Drug-induced myopathies are classified as acquired myopathies caused by exogenous factors. These pathological conditions develop in patients without muscle disease and are triggered by a variety of medicaments, including lipid-lowering drugs (LLDs) such as statins, fibrates, and ezetimibe. Here we summarise the current knowledge gained via studies conducted using various models, such as cell lines and mammalian models, and compare them with the results obtained in zebrafish (Danio rerio) studies. Zebrafish have proven to be an excellent research tool for studying dyslipidaemias as a model of these pathological conditions. This system enables in-vivo characterization of drug and gene candidates to further the understanding of disease aetiology and develop new therapeutic strategies. Our review also considers important environmental issues arising from the indiscriminate use of LLDs worldwide. The widespread use and importance of drugs such as statins and fibrates justify the need for the meticulous study of their mechanism of action and the side effects they cause.

Polystyrene Nanoplastics Can Alter the Toxicological Effects of Simvastatin on Danio rerio

Once in the environment, nanoplastics (NPls) may interact with other contaminants, such as pharmaceuticals, potentially acting as carriers and modulating their toxicity. Thus, the main aim of the current study is to investigate how polystyrene (PS) NPls (mean diameter: 60 nm) interact with simvastatin (SIM), an anticholesterolemic drug, and modulate its toxicity to zebrafish (Danio rerio) embryos. PS NPls were carboxyl group functionalized, to promote the interaction/binding of NPls with SIM (worst-case scenarios) and it was fluorescently dyed, allowing to detect the intake. Exposure was 96 h to 0–150 mg/L NPls or 0–150 µg/L SIM, as well as to dual combinations (NPls 0.015 or 1.5 mg/L and SIM 12.5 or 15 µg/L). PS NPls alone did not exert effects whereas SIM (≥12.5 µg/L) significantly delayed the hatching, decreased the heartbeat, induced edemas and mortality. The combination of NPls (1.5 mg/L) and SIM (12.5 or 15 µg/L) had significant effects on the survival of the organisms while the correspondent NPls and SIM single exposures did not have significant effects on this endpoint. Concerning the malformations appearance, SIM alone had similar effects than when in co-exposures (0.015 mg/L NPls plus 12.5 or 15 µg/L SIM). Hatching and heartbeat increased after the co-exposures SIM and NPls comparing with SIM single exposures, showing that 0.015 mg/L NPls plus 12.5 or 15 µg/L SIM did not cause significant effects on these endpoints. This study shows that NPls effects on bioavailability and toxicity of other contaminants cannot be ignored when assessing the environmental behavior and risks of NPls.

The anti-lipidemic drug simvastatin modifies epigenetic biomarkers in the amphipod Gammarus locusta

The adverse effects of certain environmental chemicals have been recently associated with the modulation of the epigenome. Although changes in the epigenetic signature have yet to be integrated into hazard and risk assessment, they are interesting candidates to link environmental exposures and altered phenotypes, since these changes may be passed across multiple non-exposed generations. Here, we addressed the effects of simvastatin (SIM), one of the most prescribed pharmaceuticals in the world, on epigenetic regulation using the amphipod Gammarus locusta as a proxy, to support its integration into hazard and environmental risk assessment. SIM is a known modulator of the epigenome in mammalian cell lines and has been reported to impact G. locusta ecological endpoints at environmentally relevant levels. G. locusta juveniles were exposed to three SIM environmentally relevant concentrations (0.32, 1.6 and 8 µg L^-1) for 15 days. Gene transcription levels of selected epigenetic regulators, i.e., dnmt1, dmap1, usp7, kat5 and uhrf1 were assessed, along with the quantification of DNA methylation levels and evaluation of key ecological endpoints: survival and growth. Exposure to 0.32 and 8 µg L^-1 SIM induced significant downregulation of DNA methyltransferase 1 (dnmt1), concomitant with global DNA hypomethylation and growth impacts. Overall, this work is the first to validate the basal expression of key epigenetic regulators in a keystone marine crustacean, supporting the integration of epigenetic biomarkers into hazard assessment frameworks.

Acute and chronic effects of environmental realistic concentrations of simvastatin in danio rerio: evidences of oxidative alterations and endocrine disruptive activity

Due to their wide use, pharmaceuticals can be discarded, metabolized and excreted into the environment, potentially affecting aquatic organisms. Lipid-regulating drugs are among the most prescribed medications around the world, to control human cholesterol levels, in more than 20 million patients. Despite this massive use of lipid-regulating drugs, particularly simvastatin, the role of these drugs is not fully characterized and understood in terms of its potential toxicological effects at the environmental level. This work intended to characterize the toxicity of an acute (120 h post-fertilization) and chronic (60 days) exposure to the antihyperlipidemic drug simvastatin (in concentrations of 92.45, 184.9, 369.8, 739.6 and 1479.2 ng L^-1), in the freshwater species zebrafish (Danio rerio). The concentrations hereby mentioned were implemented in both exposures, and were based on levels found in wastewater treatment plant influents (11.7 ± 3.2 μg L^-1), effluents (2.65 ± 0.8 μg L^-1) and Apies River (1.585 ± 0.3 μg L^-1), located in Pretoria, South Africa and, particularly in the maximum levels found in effluents from wastewater treatment plants in Portugal (369.8 ng L^-1). The acute effects were analysed focusing on behavioural endpoints (erratic and purposeful swimming), total distance travelled and swimming time), biomarkers of oxidative stress (the activities of the enzymes superoxide dismutase, catalase, glutathione peroxidase), biotransformation (the activity of glutathione S-transferases) and lipid peroxidation (levels of thiobarbituric acid reactive substances). Animals chronically exposed were also histologically analysed for sex determination and gonadal developmental stages identification. In terms of acute exposure, significant alterations were reported in terms of behavioural alterations (hyperactivity), followed by a general reduction in all tested biomarkers. Also, the analysis of chronically exposed fish evidenced no alterations in sex ratio and maturation stages. In addition, the analysis of chronically exposed fish evidenced no alterations in terms of sexual characteristics, suggesting that the chronic exposure of Danio rerio to simvastatin does not alter the sex ratio and maturation stages of individuals. This assumption suggests that simvastatin did not act as an endocrine disruptor. Moreover, the metabolism, neuronal interactions and the antioxidant properties of SIM seem to have modulated the hereby-mentioned results of toxicity. Results from this assay allow inferring that simvastatin can have an ecologically relevant impact in living organisms.

Toxicological assessment of seven unregulated drinking water Disinfection By-products (DBPs) using the zebrafish embryo bioassay

Disinfection By-products (DBPs) are formed during the chemical treatment of water for human consumption, by the reaction of raw water with chemical agents used in the different steps of the process. Disinfection is one of the most important steps, inactivating pathogens and preventing their regrowth during water distribution. However, it is also involved in DBPs formation due to the use of disinfectant agents, such as chlorine, which reacts with dissolved precursors, such as pharmaceuticals, toxins, pesticides, among others. Given their widespread occurrence, potential human health and (eco) toxicological impacts are of particular interest due to their potential carcinogenicity and various non-carcinogenic effects, such as endocrine disruption. In this study, the developmental toxicity of chemically- different unregulated DBPs was evaluated using zebrafish embryo bioassay. Embryos were exposed to different concentrations of the target DBPs and multiple endpoints, including, mortality, morphological abnormalities and locomotor behavior were assessed at specific developmental stages (24, 48, 72 and 96 hpf). The different families of DBPs tested included nitrosamines, aldehydes, alcohols and ketones. The results show that the effects were compound dependent, with EC10 values varying between 0.04 mg/L (2-ethyl-1-hexanal) to 9.2 mg/L (hexachloroacetone). Globally, several of the tested unregulated DBPs displayed higher toxicity when compared with the available data for some already regulated, such as trihalomethanes (THMs), which highlights the importance of screening the toxicity of still untested and poorly characterized DBPs.

Transgenerational inheritance of chemical-induced signature: A case study with simvastatin

The hypothesis that exposure to certain environmental chemicals during early life stages may disrupt reproduction across multiple non-exposed generations has significant implications for understanding disease etiology and adverse outcomes. We demonstrate here reproductive multi and transgenerational effects, at environmentally relevant levels, of one of the most prescribed human pharmaceuticals, simvastatin, in a keystone species, the amphipod Gammarus locusta. The transgenerational findings has major implications for hazard and risk assessment of pharmaceuticals and other contaminants of emerging concern given that transgenerational effects of environmental chemicals are not addressed in current hazard and risk assessment schemes. Considering that the mevalonate synthesis, one of the key metabolic pathways targeted by simvastatin, is highly conserved among metazoans, these results may also shed light on the potential transgenerational effects of simvastatin on other animals, including humans.

Transcriptomic data on the transgenerational exposure of the keystone amphipod Gammarus locusta to simvastatin

The use of transcriptomics data brings new insights and works as a powerful tool to explore the molecular mode of action (MoA) of transgenerational inheritance effects of contaminants of emerging concern. Therefore, in this dataset, we present the transcriptomic data of the transgenerational effects of environmentally relevant simvastatin levels, one of the most prescribed human pharmaceuticals, in the keystone amphipod species Gammarus locusta. In summary, G. locusta juveniles were maintained under simvastatin exposure up to adulthood (exposed group - F0E) and the offspring of F0E were transferred to control water for the three subsequent generations (transgenerational group - F1T, F2T and F3T). To gain insights into the biological functions and canonical pathways transgenerationally disrupted by simvastatin, a G. locusta de novo transcriptome assembly was produced and the transcriptomic profiles of three individual G. locusta females, per group, over the four generations (F0 to F3) - solvent control groups (F0.C, F1.C, F2.C and F3.C), F0 320 ng/L simvastatin exposed group (F0.320E) and F1 to F3 320 transgenerational group (F1.320T; F2.320T and F3.320T) - were analyzed. Briefly, Illumina HiSeq™ 2500 platform was used to perform RNA sequencing, and due to the unavailability of G. locusta genome, the RNA-seq datasets were assembled de novo using Trinity and annotated with Trinotate software. After assembly and post-processing steps, 106093 transcripts with N50 of 2371 bp and mean sequence length of 1343.98 bp was produced. BUSCO analyses showed a transcriptome with gene completeness of 97.5 % Arthropoda library profile. The Bowtie2, RSEM and edgeR tools were used for the differential gene expression (DEGs) analyses that allowed the identification of a high quantity of genes differentially expressed in all generations. Finally, to identify the main metabolic pathways affected by the transgenerational effects of SIM across all generations, the DGEs genes were blasted onto KEGG pathways database using the KAAS webserver. The data furnished in this article allows a better molecular understanding of the transgenerational effects produced by simvastatin in the keystone amphipod G. locusta and has major implications for hazard and risk assessment of pharmaceuticals and other emerging contaminants. This article is related to the research article entitled "Transgenerational inheritance of chemical-induced signature: a case study with simvastatin [1].

Cardiovascular drugs and lipid regulating agents in surface waters at global scale: Occurrence, ecotoxicity and risk assessment

Cardiovascular drugs and lipid regulating agents have emerged as major groups of environmental contaminants over the past decades. However, knowledge about their occurrence in freshwaters and their ecotoxicity is still limited. Here, we critically summarize the presence of 82 cardiovascular drugs and lipid regulating agents at a global-scale and represent their effects on aquatic organisms. Only about 71% of these pharmaceuticals in use have been analyzed for their residues in aquatic ecosystems and only about 24% for their effects. When detected in surface waters, they occurred at concentrations of dozens to hundreds of ng/L. In wastewaters, they reached up to several μg/L. Effects of cardiovascular drugs and lipid regulating agents have been extensively studied in fish and a few in invertebrates, such as Daphnia magna and mussels. These pharmaceuticals affect cardiac physiology, lipid metabolism, growth and reproduction. Besides, effects on spermatogenesis and neurobehavior are observed. Environmental risks are associated with beta-blockers propranolol, metoprolol, and lipid lowering agents bezafibrate and atorvastatin, where adverse effects (biochemical and transcriptional) occurred partially at surface water concentrations. In some cases, reproductive effects occurred at environmentally relevant concentrations. This review summarizes the state of the art on the occurrence of cardiovascular drugs and lipid regulating agents at a global-scale and highlights their risks to fish. Further research is needed to include more subtle changes on heart function and to explore non-investigated drugs. Their occurrence in freshwaters and impact on a diverse array of aquatic organisms are particularly needed to fully assess their environmental hazards and risks.

Chronic exposure to environmentally relevant levels of simvastatin disrupts zebrafish brain gene signaling involved in energy metabolism

Simvastatin (SIM), a hypocholesterolaemic drug belonging to the statins group, is a widely prescribed pharmaceutical for prevention of cardiovascular diseases. Several studies showed that lipophilic statins, as SIM, cross the blood-brain barrier and interfere with the energy metabolism of the central nervous system in humans and mammalian models. In fish and other aquatic organisms, the effects of SIM on the brain energy metabolism are unknown, particularly following exposure to low environmentally relevant concentrations. Therefore, the present study aimed at investigating the influence of SIM on gene signaling pathways involved in brain energy metabolism of adult zebrafish (Danio rerio) following chronic exposure (90 days) to environmentally relevant SIM concentrations ranging from 8 ng/L to 1000 ng/L. Real-time PCR was used to determine the transcript levels of several genes involved in different pathways of the brain energy metabolism (glut1b, gapdh, acadm, accα, fasn, idh3a, cox4i1, and cox5aa). The findings here reported integrated well with ecological and biochemical responses obtained in a parallel study. Data demonstrated that SIM modulates transcription of key genes involved in the mitochondrial electron transport chain, in glucose transport and metabolism, in fatty acid synthesis and β-oxidation. Further, SIM exposure led to a sex-dependent transcription profile for some of the studied genes. Overall, the present study demonstrated, for the first time, that SIM modulates gene regulation of key pathways involved in the energy metabolism in fish brain at environmentally relevant concentrations.

Microplastics induce transcriptional changes, immune response and behavioral alterations in adult zebrafish

Microplastics have become pervasive environmental pollutants in both freshwater and marine ecosystems. The presence of microplastics have been recorded in the tissues of many wild fish species, and laboratory studies have demonstrated that microplastics can exert adverse health effects. To further investigate the biological mechanisms underlying microplastics toxicity we applied an integrated approach, analyzing the effects of microplastics at transcriptomic, histological and behavioral level. Adult zebrafish have been exposed to two concentrations of high-density polyethylene and polystyrene microplastics for twenty days. Transcriptomic results indicate alterations in the expression of immune system genes and the down-regulation of genes correlated with epithelium integrity and lipid metabolism. The transcriptomic findings are supported by tissue alterations and higher occurrence of neutrophils observed in gills and intestinal epithelium. Even the daily rhythm of activity of zebrafish appears to be affected, although the regular pattern of activity is recovered over time. Considering the transcriptomic and histological findings reported, we hypothesize that the effects on mucosal epithelium integrity and immune response could potentially reduce the organism defense against pathogens, and lead to a different utilization of energy stores.

An innovative photoreactor, FluHelik, to promote UVC/H2O2 photochemical reactions: Tertiary treatment of an urban wastewater

An innovative photoreactor, FluHelik, was used to promote the degradation of contaminants of emerging concern (CECs) by a photochemical UVC/H₂O₂ process. First, the system was optimized for the oxidation of a model antibiotic, oxytetracycline (OTC), using both ultrapure water (UPW) and a real urban wastewater (UWW) (collected after secondary treatment) as solution matrices. Following, the process was evaluated for the treatment of a UWW spiked with a mixture of OTC and 10 different pharmaceuticals established by the Swiss legislation at residual concentrations (∑CECs <660 μg L^-1). The performance of the FluHelik reactor was analyzed both at lab and pre-pilot scale in multiple and single pass flow modes. The efficiency of the FluHelik photoreactor, at lab-scale, was evaluated at different operational conditions (H₂O₂ concentration, UVC lamp power (4, 6 and 11 W) and flow rate) and further compared with a conventional Jets photoreactor. Both photoreactors exhibited similar OTC removal efficiencies at the best conditions; however, the FluHelik reactor showed to be more efficient (1.3 times) in terms of mineralization when compared with the Jets reactor. Additionally, the efficiency of the UVC/H₂O₂ photochemical system using the FluHelik photoreactor in reducing the toxicity of the real effluent containing 11 pharmaceuticals was evaluated through zebrafish (Danio rerio) embryo toxicity bioassays. FluHelik scale-up from laboratory to pre-pilot to promote UVC/H₂O₂ photochemical process proved to be feasible.