Evaluation of Genomic Damage in Peripheral Lymphocytes from Occupationally Exposed Anesthetists: Assessment of the Effects of Age, Sex, and GSTT1 Gene Polymorphism

Modulation of gene expression and influence of gene polymorphisms related to genotoxicity and redox status on occupational exposure to inhaled anesthetics

The extensive use of inhalational anesthetics contributes to both indoor and outdoor (environmental) pollution. The influence of genetic susceptibility on DNA damage and oxidative stress and the possible modulation of gene expression have not yet been investigated upon occupational exposure to waste anesthetic gases (WAGs). This study assessed 8-oxoguanine DNA glycosylase 1 (OGG1) and superoxide dismutase 2 (SOD2) gene expression, which are related to oxidized DNA repair and antioxidant capacity, respectively, and the influence of their polymorphisms (OGG1 rs1052133 and SOD2 rs4880) in 100 professionals highly exposed to WAGs and 93 unexposed volunteers (control group). Additionally, X-ray repair cross complementing 1 (XRCC1 rs25487 and rs1799782) and ataxia telangiectasia mutated (ATM rs600931) gene polymorphisms as well as genetic instability (micronucleus-MN and nuclear bud-NBUD) and oxidative stress (malondialdehyde-MDA and ferric reducing antioxidant power-FRAP) biomarkers were assessed in the groups (control and exposed) and in the subgroups of the exposed group according to job occupation (anesthesiologists versus surgeons/technicians). Except for the ATM TT controls (associated with increased FRAP), there were no influences of OGG1, XRCC1, ATM, and SOD2 polymorphisms on MN, NBUD, MDA, and FRAP values in exposed or control subjects. No significant difference in the expression of either gene evaluated (OGG1 and SOD2) was found between the exposed and control groups. Increased OGG1 expression was observed among OGG1 -/Cys individuals only in the control group. Among the exposed group, anesthesiologists had a greater duration of WAG exposure (both h/week and years) than surgeons/technicians, which was associated with increased MDA and decreased antioxidant capacity (FRAP) and SOD2 expression (redox status). Higher expression of OGG1 was found in -/Cys surgeons/technicians than in anesthesiologists with the same genotype. Increased antioxidant capacity was noted in the surgeons/technicians carrying the ATM T allele and in those carrying XRCC1 -/Gln. Increased MN was influenced by OGG1 -/Cys in surgeons/technicians. Anesthesiologists with ATM CC exhibited increased MN, and those carrying the C allele (CC/CT genotype) exhibited increased NBUD. SOD2 polymorphism did not seem to be relevant for WAG exposure. These findings contribute to advancing the knowledge on genetic susceptibility/gene expression/genetic instability/oxidative stress, including differences in job occupation considering the workload, in response to occupational exposure to WAGs.

Waste anesthetic gases have a significant association with deoxyribonucleic acid (DNA) damage: A systematic review and meta-analysis of 2,732 participants

Introduction

Operating room workers are at risk of experiencing adverse effects due to occupational exposure to waste anesthetic gases (WAGs). One of the consequences of long-term WAGs exposure is the probability of developing deoxyribonucleic acid (DNA) damage. This systematic review investigated the link between WAGs and DNA damage in operating room workers.

Methods

PubMed, Science Direct, ProQuest, Scopus, and EbscoHost, as well as hand-searching, were used to find literature on the relationship between WAGs and DNA damage. Three independent reviewers independently assessed the study's quality. Meta-analysis was conducted for several DNA damage indicators, such as comet assay (DNA damage score, tail's length, tail's DNA percentage), micronuclei formation, and total chromosomal aberration.

Results

This systematic review included 29 eligible studies (2732 participants). The majority of the studies used a cross-sectional design. From our meta-analysis, which compared the extent of DNA damage in operating room workers to the unexposed group, operating room workers exposed to WAGs had a significantly higher DNA damage indicator, including DNA damage score, comet tail's length, comet tail's DNA percentage, micronuclei formation, and total chromosomal aberration (p < 0.05) than non-exposed group.

Conclusion

Waste anesthetic gases have been found to significantly impact DNA damage indicators in operating room personnel, including comet assay, micronuclei development, and chromosomal aberration. To reduce the impact of exposure, hospital and operating room personnel should take preventive measures, such as by adapting scavenger method.

Regular Sport Activity Is Able to Reduce the Level of Genomic Damage

Regular physical activity is considered one of the most valid tools capable of reducing the risk of onset of many diseases in humans. However, it is known that intense physical activity can induce high levels of genomic damage, while moderate exercise can elicit a favorable adaptive response by the organism. We evaluated, by the buccal micronuclei assay, the frequencies of micronuclei, nuclear buds and binucleated cells in a sample of amateur athletes practicing different disciplines, comparing the obtained data with those of subjects who practiced sports just occasionally and subjects that did not practice sport at all. The aim was to evaluate whether physical activity affects background levels of genomic damage and whether the different sports disciplines, as well as some gene polymorphisms, differentially affect these levels. A total of 206 subjects, 125 athletes and 81 controls, were recruited. Athletes showed significantly lower values of micronuclei, nuclear buds and binucleated cells with respect to controls. Sprinters and Martial Artists displayed significantly higher frequencies of micronuclei than other categories of athletes. Finally, neither sex nor gene polymorphisms seemed to influence the levels of genomic damage, confirming that the observed genomic damage is probably due to the nature of the sport activity.

Evaluation of genetic instability, oxidative stress, and metabolism-related gene polymorphisms in workers exposed to waste anesthetic gases

Professionals who work in operating rooms (ORs) may be exposed daily to waste anesthetic gases (WAGs) due to the use of inhalational anesthetics. Considering the controversial findings related to genetic damage and redox status in addition to a lack of knowledge about the effect of polymorphisms in genes related to phase I and II detoxification upon occupational exposure to WAGs, this cross-sectional study is the first to jointly evaluate biomarkers of genetic instability, oxidative stress, and susceptibility genes in professionals occupationally exposed to high trace amounts of halogenated (≥ 7 ppm) and nitrous oxide (165 ppm) anesthetics in ORs and in individuals not exposed to WAGs (control group). Elevated rates of buccal micronucleus (MN) and nuclear bud (NBUD) were observed in the exposure group and in professionals exposed aged more than 30 years. Exposed males showed a higher antioxidant capacity, as determined by the ferric reducing antioxidant power (FRAP), than exposed females; exposed females had higher frequencies of MN and NBUD than nonexposed females. Genetic instability (MN) was observed in professionals with greater weekly WAG exposure, and those exposed for longer durations (years) exhibited oxidative stress (increased lipid peroxidation and decreased FRAP). Polymorphisms in metabolic genes (cytochrome P450 2E1 (CYP2E1) and glutathione S-transferases (GSTs)) did not exert an effect, except for the effects of the GSTP1 (rs1695) AG/GG polymorphism on FRAP (both groups) and GSTP1 AG/GG and GSTT1 null polymorphisms, which were associated with greater FRAP values in exposed males. Minimizing WAG exposure is necessary to reduce impacts on healthcare workers.

Effect of simultaneous exposure to inhalational anesthetics and radiation on the adaptive response in operating room personnel

Some operating room personnel, such as orthopedic surgeons, are exposed simultaneously to inhalational anesthetics (IAs) and radiation that both can cause DNA damage. Some studies have shown that low doses of radiation reduce DNA damage when the cells are followed by a higher dose of the same or related agent. This study, therefore, set out to compare DNA damage in the anesthesiologists, radiologists, orthopedic surgeons, and healthcare staff (non-exposed group). In this cross-sectional study, breathing zone concentrations of anesthetic gas nitrous oxide (N₂O) were measured in the studied groups using standard method. Additionally, DNA damage was measured by micronucleus (MN) assay. The mean concentrations of N₂O in the anesthesiologists and orthopedic surgeons were 450.27 ± 327.44 ppm and 313.64 ± 216.14 ppm, respectively. The mean annual exposure to X-rays radiation in radiologists and orthopedic surgeons was 15.65 ± 8.46 mSy/year and 3.56 ± 1.32 mSy/year, respectively. MN frequencies were significantly higher in anesthesiologists and radiologists exposed to IAs and X-rays radiation respectively than in the non-exposed healthcare staff. While, there were no statistically significant differences between MN frequencies of orthopedic surgeons exposed to both IAs and radiation and healthcare staff. These findings suggest that an earlier exposure of orthopedic surgeons to a small dose of ionizing radiation can increase their resistance to genotoxicity caused by high doses of N₂O, a phenomenon that is called adaptive response.

The formation of SCEs as an effect of occupational exposure to formaldehyde

Formaldehyde (FA) is a ubiquitous toxic chemical employed worldwide due to its disinfectant and preservative properties. Despite being classified as a human carcinogen, FA is still employed as formalin in pathology wards as standard fixative. We evaluated its relationship with the formation of sister-chromatid exchanges (SCEs) in cultured peripheral blood lymphocytes on 57 pathologists and 48 controls and the risk/protective role played by several genetic polymorphisms. All subjects were assessed for SCEs and genotyped for the most common cancer-associated gene polymorphisms: CYP1A1 exon 7 (A > G), CYP1A1*2A (T > C), CYP2C19*2 (G > A), GSTT1 (presence/absence), GSTM1 (presence/absence), GSTP1 (A > G), XRCC1 (G399A), XRCC1 (C194T), XRCC1 (A280G), XPC exon 15 (A939C), XPC exon 9 (C499T), TNFα − 308 G > A), IL10 − 1082 (G > A), and IL6 − 174 (G > C). Air-FA concentration was assessed through passive personal samplers. Pathologists, exposed to 55.2 μg/m³ of air-FA, showed a significantly higher SCEs frequency than controls, exposed, respectively, to 18.4 μg/m³. Air-FA was directly correlated with SCEs frequency and inversely with the replication index (RI). Regression models showed FA exposure as a significant predictor in developing SCEs, while did not highlight any role of the selected polymorphisms. Our study confirms the role of low air-FA levels as genotoxicity inductor, highlighting the importance to define exposure limits that could be safer for exposed workers.

Association between genotoxic properties of inhalation anesthetics and oxidative stress biomarkers

Exposure to inhalation anesthetics (IAs) has been associated with DNA damage as reflected in the increased frequency of micronuclei (MN) and chromosomal aberrations (CAs). The present study was undertaken to ascertain whether there was any correlation between increased MN and CA and the extent of oxidative stress as well as the antioxidant status of a group of operating room personnel exposed to a mixture of IAs, including nitrous oxide, isoflurane, and sevoflurane. In this cross-sectional study, 60 operating room personnel (exposed group) in whom the frequencies of MN and CA had already been shown to be significantly higher than those of a referent group, as well as 60 unexposed nurses, were studied. Venous blood samples were taken from all participants, and malondialdehyde (MDA) levels as an index of oxidative stress (OS) and the activity of superoxide dismutase (SOD) and levels of total antioxidant capacity (TAC) as indices of antioxidant status were measured. The level of TAC (1.76 ± 0.59 mM vs. 2.13 ± 0.64 mM, p = 0.001) and the activity of SOD (11.22 ± 5.11 U/ml vs. 13.36 ± 4.12 U/ml, p = 0.01) were significantly lower, while the mean value of MDA was significantly higher (2.46 ± 0.66 µM vs. 2.19 ± 0.68 µM, p = 0.03) in the exposed group than in the nonexposed group. After adjusting for potential confounders, there were statistically significant associations between exposure to IAs, gender, SOD, and TAC with MN frequency and between exposure to IAs and SOD with numbers of CA. The findings of the present study indicated that exposure to IAs was associated with OS, and this, in turn, may be causally linked with DNA damage.

Laryngoscopic techniques modulate anaesthesiologists' perception of halitosis in patients: A randomised controlled trial

BACKGROUND

Perception of halitosis in patients during intubation is a common and additional stressor for anaesthesiologists and may lead to potential health risks.

OBJECTIVES

We hypothesised that intubation with videolaryngoscopy could help reduce the anaesthesiologists' perception of patients' oral malodor during intubation.

DESIGN

A single-blinded, randomised controlled trial.

SETTING

Single centre general hospital, Guangdong Province, China.

PARTICIPANTS

A total of 440 patients who underwent intubation under general anaesthesia for elective surgery, aged 18 to 60 years old, American Society of Anaesthesiologists class I to III, without upper airway abnormality or airway infection were enrolled.

INTERVENTION

Patients were randomly assigned to receive either UE videolaryngoscopy (UE) or Macintosh's direct laryngoscopy (Macintosh) group. All intubations were performed by one of six very experienced anaesthesiologists.

MAIN OUTCOME MEASURES

The patient's oral odour score was measured prior to induction of anaesthesia. The anaesthesiologists' perception of the patient's oral malodor during intubation was recorded. The shortest distance from patient's mouth to the anaesthesiologist's nose (MN distance), the exertion rating and discomfort were also measured.

RESULTS

The oral malodor score did not differ in the UE and Macintosh groups prior to the induction of anaesthesia. However, the incidence of the anaesthesiologists' perception of halitosis during intubation was significantly lower in the UE group compared with the Macintosh group (P < 0.001). Similarly, the MN distance was significantly greater in the UE group compared with the Macintosh group (P < 0.001). The first-attempt success rate was higher in the UE group compared to the Macintosh group (P < 0.001). However, the exertion scores were considerably higher in the Macintosh group. After intubation, anaesthesiologists experienced more waist and shoulder discomfort with the Macintosh than the UE technique of intubation.

CONCLUSION

Compared with direct laryngoscopy, videolaryngoscopy might reduce the anaesthesiologists' perception of the patients' oral malodor, help improve first-attempt success rate, as well as alleviate the anaesthesiologists' waist and shoulder discomfort.

TRIAL REGISTRATION

Clinicaltrials.gov (ChiCTR-IOR-15007038).

Pro-Con Debate: Nitrous Oxide for Labor Analgesia

This Pro-Con debate will provide the practitioner with an evidence-based knowledge approach to assist the clinician in determining whether to employ (Pro) or not to employ (Con) this technique in the obstetrical suite for labor analgesia. Nitrous oxide has been used safely in dentistry and medicine for many centuries. However, accumulating preclinical and clinical evidence increasingly suggests previously unrecognized adverse maternal and fetal effects of nitrous oxide, which warrants reconsideration of its use in pregnant women and a more detailed informed consent. Nitrous oxide is associated with metabolic, oxidative, genotoxic, and transgenerational epigenetic effects in animals and humans that may warrant limiting its usefulness in labor. This debate will discuss and review the clinical uses, advantages, and disadvantages of nitrous oxide on occupational effects of nitrous oxide exposure, neuroapoptosis, FDA warning on inhalational anesthetics and the developing brain, research limitations, occupational exposure safety limits, effects on global warming, and potential for diversion.

Genotoxicity of inhalational anesthetics and its relationship with the polymorphisms of GSTT1, GSTM1, and GSTP1 genes

Due to their wide applications, concern exists regarding possible genotoxic effects of inhalational anesthetics (IAs) among operating room personnel. This study was undertaken to examine genotoxic properties of co-exposure to nitrous oxide, sevoflurane, and isoflurane on induction of micronucleus (MN) and chromosomal aberrations (CAs) and to determine whether any associations exist between polymorphisms of GST genes and the level of genomic damage measured by MN and CAs assays. Sixty operating room personnel and 60 unexposed referent nurses were studied. The workers' exposure to the IAs was determined. DNA damage was evaluated by MN and CAs assays. Additionally, the GSTM1, GSTT1, and GSTP1 polymorphisms were detected. The mean concentrations of nitrous oxide, isoflurane, and sevoflurane were found to be 850.92 ± 919.78, 2.40 ± 0.86, and 0.18 ± 0.14 ppm, respectively. The frequency of MN and CAs in the exposed group was significantly higher than that of the non-exposed group. The frequency of MN was significantly higher in referent nurses with null GSTT1, compared to referent nurses with positive GSTT1. The frequency of MN was significantly higher in exposed individuals carrying the combined genotype of GSTT1 (-), GSTM1 (-), and GSTP1 AG as compared with subjects carrying a combination of GSTT1 (+), GSTM1 (+), and GSTP1 AA. Statistically significant associations were noted between exposure to the IAs, gender, and the combination of the three GSTs genotypes with MN frequency. These findings indicate that inhalation exposure to IAs induces genotoxic response and the polymorphisms of GSTs genes might modulate the effect of exposure to IAs on MN.

Evaluation of baseline frequency of sister chromatid exchanges in an Italian population according to age, sex, smoking habits, and gene polymorphisms

OBJECTIVES

Increased SCEs frequencies in human lymphocytes are an indicator of spontaneous chromosome instability and could be influenced by different exogenous and endogenous factors. In this study, we evaluated the influence of age, sex, smoking habits, and genetic polymorphisms on the background levels of SCEs in peripheral blood lymphocytes.

METHODS

Two hundred-thirty healthy Italian subjects were recruited. Data about age, sex and smoking habits were recorded. Subjects were also genotyped for GSTT1, GSTM1, GSTP1 A/G, CYP1A1 Ile/Val, CYP2C19 G/A, ERCC2/XPD Lys751Gln, XRCC1 Arg194ATrp, XRCC1 Arg399Gln, and XRCC1Arg208His gene polymorphisms.

RESULTS

The frequency of SCEs/cell was 5.15 ± 1.87, with females showing a significantly higher SCEs value with respect to males (5.36 ± 2.10 and 4.82 ± 1.39, respectively). Smokers showed significantly increased levels of SCEs with respect to nonsmokers (5.93 ± 1.75 and 4.70 ± 1.79, respectively) whereas no differences were observed between heavy and light smokers. Age correlated with the RI value (P = .01) but not with the SCEs frequency (P = 07), although the 31-40 age group showed a significantly lower SCEs frequency with respect to the other age groups. A significant association was also found between GSTP2C19-AA, GSTT1-null, GSTM1-null, ERCC2/XPD Gln751Gln, and XRCC1 His208His genotypes, and higher frequencies of SCEs.

CONCLUSION

We describe the association between some phase I, phase II, and DNA-repair gene polymorphisms with increased SCEs frequencies, reinforcing the importance of genetic analysis in biomonitoring studies. Sex and age were found to be important endogenous factors that affect the level of genomic damage and the replicative capacity of cells, respectively.

Association of GSTT1 null, XPD 751 CC and XPC 939 CC genotypes with increased levels of genomic damage among hospital pathologists

CONTEXT

Hospital workers are at risk for genotoxic damage following occupationally exposure to xenobiotics. Pathologists are exposed to chemicals during their use in health care environments, particularly throughout inhalation of airborne agents, absorption through skin or contact with the patient's body fluids.

OBJECTIVE

We evaluated the level of genomic damage in a sample of 61 hospital pathologists (occupationally exposed to antineoplastic drugs and sterilizing agents) and 60 control subjects.

MATERIALS AND METHODS

Lymphocytes were analyzed by SCEs and CAs assays and genotyped for GSTT1, GSTM1, CYP1A1 Ile/Val, XPD (A751C) and XPC (A939C) gene polymorphisms.

RESULTS

Pathologists showed significantly higher frequencies of SCEs and CAs with respect to control subjects. GSTT1 null genotype was found to be associated with higher SCEs and CAs frequencies, whereas XPD 751 CC and XPC 939 CC genotypes only with a higher level of SCEs.

DISCUSSION AND CONCLUSIONS

The SCEs and CAs results are consistent with other published data, placing hospital workers as a category at risk for genotoxic damage caused by chronic exposure to xenobiotics. The higher levels of cytogenetic damage observed among GSTT1 null, XPD 751 and XPC 939 CC homozygote subjects confirm the importance of the genetic polymorphisms analysis associated to genotoxicological studies.