Genotoxic evaluation of selective serotonin-reuptake inhibitors by use of the somatic mutation and recombination test in Drosophila melanogaster

Genotoxicity responses of single and mixed exposure to heavy metals (cadmium, silver, and copper) as environmental pollutants in Drosophila melanogaster

Heavy metals are now persistently present in living things' environments, in addition to their potential toxicity. Therefore, the aim of this study was to utilize D. melanogaster to determine the biological effects induced by different heavy metals including cadmium chloride (CdCl2), copper (II) sulfate pentahydrate (CuSO 4.5 H2O), and silver nitrate (AgNO3). In vivo experiments were conducted utilizing three low and environmentally relevant concentrations from 0.01 to 0.5 mM under single and combined exposure scenarios on D. melanogaster larvae. The endpoints measured included viability, reactive oxygen species (ROS) generation and genotoxic effects using Comet assay and the wing-spot test. Results indicated that tested heavy metals were not toxic in the egg-to adult viability. However, combined exposure (CdCl2+AgNO3 and CdCl2+AgNO3+CuSO 4.5 H2O) resulted in significant genotoxic and unfavorable consequences, as well as antagonistic and/or synergistic effects on oxidative damage and genetic damage.

Human Hazard Assessment Using Drosophila Wing Spot Test as an Alternative In Vivo Model for Genotoxicity Testing-A Review

Genomic instability, one of cancer's hallmarks, is induced by genotoxins from endogenous and exogenous sources, including reactive oxygen species (ROS), diet, and environmental pollutants. A sensitive in vivo genotoxicity test is required for the identification of human hazards to reduce the potential health risk. The somatic mutation and recombination test (SMART) or wing spot test is a genotoxicity assay involving Drosophila melanogaster (fruit fly) as a classical, alternative human model. This review describes the principle of the SMART assay in conjunction with its advantages and disadvantages and discusses applications of the assay covering all segments of health-related industries, including food, dietary supplements, drug industries, pesticides, and herbicides, as well as nanoparticles. Chemopreventive strategies are outlined as a global health trend for the anti-genotoxicity of interesting herbal extract compounds determined by SMART assay. The successful application of Drosophila for high-throughput screening of mutagens is also discussed as a future perspective.

A Systematic Review on the Genotoxic Effects of Selective Serotonin Reuptake Inhibitors

Depression is a mental disorder and a major public health concern affecting millions of people worldwide. It is a common disorder that has been associated with several medical comorbidities often linked with aging, such as dementia, type II diabetes, cardiovascular and cerebrovascular diseases, as well as metabolic syndrome. There are a variety of medications available for depression treatment. Selective serotonin reuptake inhibitors (SSRIs) are one of the antidepressant drug classes that are most widely used to treat depressive disorders and depressive symptoms in other diseases. Due to many contradictory findings on the adverse effects and toxicities of SSRIs (especially genotoxicities), we reviewed the genotoxic effects of these drugs. Based on the guidelines proposed in the PRISMA statement, we performed a systematic review by searching international electronic databases including PubMed, Scopus, Embase, and Web of Science to find the published documents on SSRIs and their genotoxic effects from January 1990 to November 2019. After the removal of 203 duplicate articles, 385 articles were screened and 167 articles met the inclusion criteria and qualified for evaluation of their full texts. After this, 26 articles were appropriate for final review. This revealed that the proportion of genotoxicities was highest for citalopram and fluoxetine, with a smaller proportion for sertraline. Limited documentations showed genotoxic and partial genotoxic effects for paroxetine and escitalopram, respectively. Although a number of studies have found genotoxic effects of SSRIs, there are also some factors including doses, duration of exposure, model of experiments, and the type of technique assay that may affect the results.

Sertraline induces DNA damage and cellular toxicity in Drosophila that can be ameliorated by antioxidants

Sertraline hydrochloride is a commonly prescribed antidepressant medication that acts by amplifying serotonin signaling. Numerous studies have suggested that children of women  taking sertraline during pregnancy have an increased risk of developmental defects. Resolving the degree of risk for human fetuses requires comprehensive knowledge of the pathways affected by this drug. We utilized a Drosophila melanogaster model system to assess the effects of sertraline throughout development. Ingestion of sertraline by females did not affect their fecundity or embryogenesis in their progeny. However, larvae that consumed sertraline experienced delayed developmental progression and reduced survival at all stages of development. Genetic experiments showed that these effects were mostly independent of aberrant extracellular serotonin levels. Using an ex vivo imaginal disc culture system, we showed that mitotically active sertraline-treated tissues accumulate DNA double-strand breaks and undergo apoptosis at increased frequencies. Remarkably, the sertraline-induced genotoxicity was partially rescued by co-incubation with ascorbic acid, suggesting that sertraline induces oxidative DNA damage. These findings may have implications for the biomedicine of sertraline-induced birth defects.

In vitro cytogenotoxic evaluation of sertraline

Sertraline (SRT) is an antidepressant agent used as a neuronal selective serotonin-reuptake inhibitor (SSRI). SRT blocks serotonin reuptake and increases serotonin stimulation of somatodendritic serotonin 1A receptor (5-HT1AR) and terminal autoreceptors in the brain. In the present study, the genotoxic potential of SRT was evaluated using cytokinesis-block micronucleus (CBMN) cytome assay in peripheral blood lymphocytes of healthy human subjects. DNA cleavage-protective effects of SRT were analyzed on plasmid pBR322. In addition, biochemical parameters of total oxidant status (TOS) and total antioxidant status (TAS) in blood plasma were measured to quantitate oxidative stress. Human peripheral blood lymphocytes were exposed to four different concentrations (1.25, 2.5, 3.75 and 5 μg/mL) of SRT for 24- or 48-h treatment periods. In this study, SRT was not found to induce MN formation either in 24- or 48-h treatment periods. In contrast, SRT concentration-dependently decreased the percentage of MN and MNBN (r=-0.979, p<0.01; r=-0.930, p<0.05, respectively) when it was present for the last 48 hr (48-h treatment) of the culture period. SRT neither demonstrated a cleavage activity on plasmid DNA nor conferred DNA protection against H₂O₂. The application of various concentrations of SRT significantly increased the TOS and oxidative stress index (OSI) in human peripheral blood lymphocytes for both the 24- and 48-h treatment periods. Morover, the increase in TOS was potent as the positive control MMC at both treatment times. However, SRT did not alter the TAS levels in either 24- or 48-h treatment periods when compared to control. In addition, exposing cells to SRT caused significant decreases in the nuclear division index at 1.25, 2.50 and 3.75 μg/mL in the 24-h and at the highest concentration (5 μg/mL) in the 48-h treatment periods. Our results suggest that SRT may have cytotoxic effect via oxidative stress on cultured human peripheral blood lymphocytes.

Effects of selective serotonin reuptake inhibitors on DNA damage in patients with depression

BACKGROUND

The relationship between depression and increased oxidative stress is well known. DNA damage by oxidation factors is an important cause of the aging process in psychiatric disorders.

AIMS

Owing to the scarcity of human studies and high inconsistencies in studies of the effects of antidepressants on DNA damage, the current study was undertaken to investigate the effects of depression and its treatment on DNA damage.

METHODS

In a 15-week open-label study of citalopram (n = 25) and sertraline (n = 20), levels of DNA damage were measured by comet assay, proinflammatory (Interlukin-6 (IL-6)) and oxidative DNA damage (8-hydroxy-2'-deoxyguanosine (8-OHdG)) markers by ELISA, and gene expression of base excision repair enzymes (8-oxoguanine glycosylase (OGG1) and poly (ADP)-ribose polymerase-1 (PARP1)) by quantitative real-time polymerase chain reaction in healthy control patients (n = 14), with depression at the baseline and the same patients after week 15.

RESULTS

DNA damage, 8-OHdG, IL-6 and expression of PARP1 were elevated in patients with depression compared with the healthy controls (p < 0.001). Selective serotonin reuptake inhibitor (SSRI) therapy could significantly reduce the depression score (p < 0.01), DNA damage (p < 0.001), as well as 8-OHdG and IL-6 (p < 0.0001). Nevertheless, the expression of PARP1 and OGG1 showed no significant changes after treatment.

CONCLUSIONS

This is the first study on the effect of SSRIs on the DNA damage and some of the repair enzymes in depression. Based on the results, depression can cause increased DNA damage. This damage is followed by activation of compensatory mechanisms whereby the expression of DNA damage repair enzymes is elevated. Finally, the treatment of psychiatric disorder by antidepressants can lower the level of oxidative DNA damage.

DNA Damage and Pulmonary Hypertension

Pulmonary hypertension (PH) is defined by a mean pulmonary arterial pressure over 25 mmHg at rest and is diagnosed by right heart catheterization. Among the different groups of PH, pulmonary arterial hypertension (PAH) is characterized by a progressive obstruction of distal pulmonary arteries, related to endothelial cell dysfunction and vascular cell proliferation, which leads to an increased pulmonary vascular resistance, right ventricular hypertrophy, and right heart failure. Although the primary trigger of PAH remains unknown, oxidative stress and inflammation have been shown to play a key role in the development and progression of vascular remodeling. These factors are known to increase DNA damage that might favor the emergence of the proliferative and apoptosis-resistant phenotype observed in PAH vascular cells. High levels of DNA damage were reported to occur in PAH lungs and remodeled arteries as well as in animal models of PH. Moreover, recent studies have demonstrated that impaired DNA-response mechanisms may lead to an increased mutagen sensitivity in PAH patients. Finally, PAH was linked with decreased breast cancer 1 protein (BRCA1) and DNA topoisomerase 2-binding protein 1 (TopBP1) expression, both involved in maintaining genome integrity. This review aims to provide an overview of recent evidence of DNA damage and DNA repair deficiency and their implication in PAH pathogenesis.

Analysis of genotoxic activity of ketamine and rocuronium bromide using the somatic mutation and recombination test in Drosophila melanogaster

The present study evaluated the mutagenic and recombinogenic effects of two commonly used anesthetic agents, ketamine and rocuronium bromide, in medicine using the wing somatic mutation and recombination test (SMART) in Drosophila. The standard (ST) cross and the high-bioactivation (HB) cross with high sensitivity to procarcinogens and promutagens were used. The SMART test is based on the loss of heterozygosity, which occurs via various mechanisms, such as chromosome loss and deletion, half-translocation, mitotic recombination, mutation, and non-disjunction. Genetic alterations occurring in the somatic cells of the wing's imaginal discs result in mutant clones in the wing blade. Three-day-old trans-heterozygous larvae with two recessive markers, multiple wing hairs (mwh) and flare (flr(3)), were treated with ketamine and rocuronium bromide. Analysis of the ST cross indicated that ketamine exhibited genotoxicity activity and that this activity was particularly dependent on homologous mitotic recombination at concentrations of 250 μg/ml and above. Rocuronium bromide did not exert mutagenic and/or recombinogenic effects. In the HB cross, ketamine at a concentration of 1000 μg/ml and rocuronium bromide at all concentrations, with the exception of 250 μg/ml (inconclusive), exerted genotoxic effects, which could also be associated with the increase in mitotic recombination.

Genotoxic evaluation of bupivacaine and levobupivacaine in the Drosophila wing spot test

Bupivacaine and levobupivacaine are amino amide local anesthetics commonly used in medical practice. Although bupivacaine consists of a racemic mixture of S (-)-bupivacaine and R (+)-bupivacaine enantiomers, levobupivacaine is comprised of pure S (-)-bupivacaine. It has been known that levobupivacaine is preferable to bupivacaine since it may cause cardiovascular and nervous system toxicity. For determining genotoxicity of these anesthetics, we used the wing somatic mutation and recombination test in Drosophila melanogaster. Three-day-old trans-heterozygous larvae were treated with bupivacaine and levobupivacaine. Analysis of the standard crosses indicated that bupivacaine and levobupivacaine did not exhibit mutagenic or recombinogenic activity until toxic doses have been reached at the larval stage. When we examined bupivacaine and levobupivacaine in the HB cross, bupivacaine did not exhibit any genotoxicity at high concentrations (500 µg/mL), but levobupivacaine did exert genotoxicity at high concentrations (1000 µg/mL)-depending on the substantial recombinogenic effect.

Evaluation of Duloxetine as Micronuclei Inducer in an Acute and a Subchronic Assay in Mouse

Duloxetine is a widely used antidepressant worldwide. In the present report, we evaluated its capacity to induce micronucleated polychromatic erythrocytes (MNPEs) and micronucleated normochromatic erythrocytes (MNNEs) in mice. Two assays were performed, one with a single chemical administration and the other with daily chemical administration. In the first, we administered the antidepressant once to groups of 5 mice by the intragastric (i.g.) route (2, 20, and 200 mg/kg) and performed the analysis at 24, 48, and 72 h postadministration. A control group administered i.g. distilled water was included in the assay, as well as another treated with the micronuclei-inducing chemical daunorubicin (2.5 mg/kg, injected intraperitoneally (i.p.)). In this assay, we found significant damage induced by duloxetine starting from the first time evaluated, showing the highest MNPE increase at the end of the assay. We observed a saturation effect as well, suggested by a decreasing relative efficiency with respect to each tested dose. In a second assay, we administered the antidepressant i.g. every day for 5 weeks (2, 6, and 12 mg/kg), and micronuclei analysis was performed at the end of each week. In this study, we also found a significant increase in both MNPEs and MNNEs which was clear by the second week of administration. Our results suggest that short-term as well as cumulative damage is produced by duloxetine. Thus, confirmation of the observed genotoxic potential in other models seems advisable, as well as caution when prescribing this antidepressant.