DNA damage effects of inhalation anesthetics in human bronchoalveolar cells

Repeated Contrast-Enhanced Micro-CT Examinations Decrease Animal Welfare and Influence Tumor Physiology

OBJECTIVES

Computed tomography (CT) imaging is considered relatively safe and is often used in preclinical research to study physiological processes. However, the sum of low-dose radiation, anesthesia, and animal handling might impact animal welfare and physiological parameters. This is particularly relevant for longitudinal studies with repeated CT examinations. Therefore, we investigated the influence of repeated native and contrast-enhanced (CE) CT on animal welfare and tumor physiology in regorafenib-treated and nontreated tumor-bearing mice.

MATERIAL AND METHODS

Mice bearing 4T1 breast cancer were divided into 5 groups: (1) no imaging, (2) isoflurane anesthesia only, (3) 4 mGy CT, (4) 50 mGy CT, and (5) CE-CT (iomeprol). In addition, half of each group was treated with the multikinase inhibitor regorafenib. Mice were imaged 3 times within 1 week under isoflurane anesthesia. Behavioral alterations were investigated by score sheet evaluation, rotarod test, heart rate measurements, and fecal corticosterone metabolite analysis. Tumor growth was measured daily with a caliper. Tumors were excised at the end of the experiment and histologically examined for blood vessel density, perfusion, and cell proliferation.

RESULTS

According to the score sheet, animals showed a higher burden after anesthesia administration and in addition with CT imaging ( P < 0.001). Motor coordination was not affected by native CT, but significantly decreased after CE-CT in combination with the tumor therapy ( P < 0.001). Whereas tumor growth and blood vessel density were not influenced by anesthesia or imaging, CT-scanned animals had a higher tumor perfusion ( P < 0.001) and a lower tumor cell proliferation ( P < 0.001) for both radiation doses. The most significant difference was observed between the control and CE-CT groups.

CONCLUSION

Repeated (CE-) CT imaging of anesthetized animals can lead to an impairment of animal motor coordination and, thus, welfare. Furthermore, these standard CT protocols seem to be capable of inducing alterations in tumor physiology when applied repetitively. These potential effects of native and CE-CT should be carefully considered in preclinical oncological research.

Neonatal Anesthesia and Oxidative Stress

Neonatal anesthesia, while often essential for surgeries or imaging procedures, is accompanied by significant risks to redox balance in the brain due to the relatively weak antioxidant system in children. Oxidative stress is characterized by concentrations of reactive oxygen species (ROS) that are elevated beyond what can be accommodated by the antioxidant defense system. In neonatal anesthesia, this has been proposed to be a contributing factor to some of the negative consequences (e.g., learning deficits and behavioral abnormalities) that are associated with early anesthetic exposure. In order to assess the relationship between neonatal anesthesia and oxidative stress, we first review the mechanisms of action of common anesthetic agents, the key pathways that produce the majority of ROS, and the main antioxidants. We then explore the possible immediate, short-term, and long-term pathways of neonatal-anesthesia-induced oxidative stress. We review a large body of literature describing oxidative stress to be evident during and immediately following neonatal anesthesia. Moreover, our review suggests that the short-term pathway has a temporally limited effect on oxidative stress, while the long-term pathway can manifest years later due to the altered development of neurons and neurovascular interactions.

Anesthesia-Induced Oxidative Stress: Are There Differences between Intravenous and Inhaled Anesthetics?

Agents used for the induction of anesthesia have been shown to either promote or mitigate oxidative stress. A fine balance between the presence of reactive oxygen species (ROS) and antioxidants is crucial for the proper normal functioning of the cell. A basal concentration of ROS is essential for the manifestation of cellular functions, whereas disproportionate levels of ROS cause damage to cellular macromolecules such as DNA, lipids, and proteins, eventually leading to necrosis and apoptosis. Increased ROS has been linked with numerous illnesses, such as cardiovascular, immune system, liver, and kidney, and has been shown to promote cancer and accelerate aging. Knowledge of the various pharmacologic agents that increase or reduce oxidative stress may promote a safer way of inducing anesthesia. Furthermore, surgery itself leads to increased ROS production and ischemia/reperfusion injury. Indeed, increased perioperative oxidative stress has been correlated with increased postoperative complications and prolonged recovery. Anesthesiologists care for patients during the whole spectrum of perioperative care and thus are in a unique position to deliver countermeasures to oxidative stress. Using preferentially an induction agent which reduces oxidative stress might lead to better clinical outcomes and fewer postoperative complications. Propofol has been shown in several studies to reduce oxidative stress, which reduces postoperative complications and leads to a faster recovery, and thus might represent the preferred induction agent in the right clinical setting.

Dynamic thiol/disulphide balance in patients undergoing hypotensive anesthesia in elective septoplasties

OBJECTIVE

We aimed to investigate the effects of hypotensive anaesthesia on oxidative stress with serum thiol/disulphide balance in patients undergoing elective septoplasty procedures under general anaesthesia.

METHODS

Seventy-two patients between the ages of 18-60, with a physical condition I -II, according to the American Society of Anesthesiologists, were included in this prospective observational study. Septoplasty was chosen for standard surgical stress. According to the maintenance of anaesthesia, patients were divided into the groups as Hypotensive Anaesthesia (n = 40) and Normotensive Anaesthesia (n = 32). Serum thiol/disulphide levels were measured by the method developed by Erel & Neşelioğlu.

RESULTS

The native thiol and total thiol values of both groups measured at the 60th min intraoperatively were significantly lower than the preoperative values (both P < .01). Intraoperatively, at the 60th min, there was no significant difference in terms of post-native thiol and post-total thiol levels between hypotensive and normotensive anaesthesia groups (P = .68 and .81, respectively). Age >40 years and female gender were found to have a significant effect on dynamic oxidative stress (P = .002 and .001, respectively).

CONCLUSION

This pilot study has found that hypotensive anaesthesia had no adverse effect on dynamic thiol/disulphide balance in elective surgeries.

Inhaled Anesthetics: Environmental Role, Occupational Risk, and Clinical Use

Inhaled anesthetics have been in clinical use for over 150 years and are still commonly used in daily practice. The initial view of inhaled anesthetics as indispensable for general anesthesia has evolved during the years and, currently, its general use has even been questioned. Beyond the traditional risks inherent to any drug in use, inhaled anesthetics are exceptionally strong greenhouse gases (GHG) and may pose considerable occupational risks. This emphasizes the importance of evaluating and considering its use in clinical practices. Despite the overwhelming scientific evidence of worsening climate changes, control measures are very slowly implemented. Therefore, it is the responsibility of all society sectors, including the health sector to maximally decrease GHG emissions where possible. Within the field of anesthesia, the potential to reduce GHG emissions can be briefly summarized as follows: Stop or avoid the use of nitrous oxide (N2O) and desflurane, consider the use of total intravenous or local-regional anesthesia, invest in the development of new technologies to minimize volatile anesthetics consumption, scavenging systems, and destruction of waste gas. The improved and sustained awareness of the medical community regarding the climate impact of inhaled anesthetics is mandatory to bring change in the current practice.

Role of Sevoflurane on Natural Killer Group 2, Member D-Mediated Immune Response in Non-Small-Cell Lung Cancer: An In Vitro Study

Background

The purpose of this study was to investigate the effects of sevoflurane on cancer immunosurveillance and metastasis in non-small-cell lung cancer (NSCLC).

Material/Methods

NCI-H23 cells, a human NSCLC cell line, were incubated with or without sevoflurane at the concentrations of 0, 12.5, 25, 50, 100, and 200 μM for 6 h. Cell viability, the expression of natural killer group 2, member D ligands (NKG2D ligands: UL16-binding proteins 1–3 [ULBP1–3] and major histocompatibility complex class I chain-related molecules A/B [MICA/B]), the expression of matrix metalloproteinases (MMPs), NK cell-mediated cytotoxicity, and cancer cell migration were measured.

Results

At 12.5, 25, 50, and 100 μM, sevoflurane increased the expression of NKG2D ligands (ULBP2–3 and MICA, ULBP1–3, ULBP1–3, and ULBP1, respectively). Sevoflurane decreased the expression of NKG2D ligands at 200 μM (MICA/B). NK cell-mediated lysis of NCI-H23 cells at 200 μM sevoflurane was significantly reduced compared with the control (P=0.025; target cell: effect cell=1: 10). Sevoflurane increased the expression of MMP-1, -2, and -9 and increased cell migration in NCI-H23 cells at 50, 100, and 200 μM (P=0.001, 0.035, and 0.039, respectively, compared with the control after 18 h of wound formation).

Conclusions

Sevoflurane could suppress NKG2D-mediated NK cell cytotoxicity and increased expression of MMPs and migration in NCI-H23 cells. Further research is needed to determine the effects of sevoflurane on cancer immunosurveillance and metastasis in NSCLC.

Oxidative stress under general intravenous and inhalation anaesthesia

Oxidative stress occurs when reactive oxygen species (ROS) production overwhelms cell protection by antioxidants. This review is focused on general anaesthesia-induced oxidative stress because it increases the rate of complications and delays recovery after surgery. It is important to know what effects of anaesthetics to expect in terms of oxidative stress, particularly in surgical procedures with high ROS production, because their either additive or antagonistic effect may be pivotal for the outcome of surgery. In vitro and animal studies on this topic are numerous but show large variability. There are not many human studies and what we know has been learned from different surgical procedures measuring different endpoints in blood samples taken mostly before and after surgery. In these studies most intravenous anaesthetics have antioxidative properties, while volatile anaesthetics temporarily increase oxidative stress in longer surgical procedures.

General anesthesia, germ cells and the missing heritability of autism: an urgent need for research

Agents of general anesthesia (GA) are commonly employed in surgical, dental and diagnostic procedures to effectuate global suppression of the nervous system, but in addition to somatic targets, the subject's germ cells-from the embryonic primordial stage to the mature gametes-may likewise be exposed. Although GA is generally considered safe for most patients, evidence has accumulated that various compounds, in particular the synthetic volatile anesthetic gases (SVAGs) such as sevoflurane, can exert neurotoxic, genotoxic and epigenotoxic effects, with adverse consequences for cellular and genomic function in both somatic and germline cells. The purpose of this paper is to review the evidence demonstrating that GA, and in particular, SVAGs, may in some circumstances adversely impact the molecular program of germ cells, resulting in brain and behavioral pathology in the progeny born of the exposed cells. Further, we exhort the medical and scientific communities to undertake comprehensive experimental and epidemiological research programs to address this critical gap in risk assessment.