Genetic toxicology of remifentanil, an opiate analgesic

The Genotoxicity of Acrylfentanyl, Ocfentanyl and Furanylfentanyl Raises the Concern of Long-Term Consequences

Three fentanyl analogues Acrylfentanyl, Ocfentanyl and Furanylfentanyl are potent, rapid-acting synthetic analgesics that recently appeared on the illicit market of new psychoactive substances (NPS) under the class of new synthetic opioids (NSO). Pharmacotoxicological data on these three non-pharmaceutical fentanyl analogues are limited and studies on their genotoxicity are not yet available. Therefore, the aim of the present study was to investigate this property. The ability to induce structural and numerical chromosomal aberrations in human lymphoblastoid TK6 cells was evaluated by employing the flow cytometric protocol of the in vitro mammalian cell micronucleus test. Our study demonstrated the non-genotoxicity of Fentanyl, i.e., the pharmaceutical progenitor of the class, while its illicit non-pharmaceutical analogues were found to be genotoxic. In particular, Acrylfentanyl led to a statistically significant increase in the MNi frequency at the highest concentration tested (75 μM), while Ocfentanyl and Furanylfentnyl each did so at both concentrations tested (150, 200 μM and 25, 50 μM, respectively). The study ended by investigating reactive oxygen species (ROS) induction as a possible mechanism linked to the proved genotoxic effect. The results showed a non-statistically significant increase in ROS levels in the cultures treated with all molecules under study. Overall, the proved genotoxicity raises concern about the possibility of serious long-term consequences.

Determination of DNA damage by alkaline halo and comet assay in patients under sevoflurane anesthesia

In this study, we report data on the possible genotoxic effect of inhalation anesthetic sevoflurane (SVF) by comparing two techniques, comet and alkaline halo assay, in peripheral blood lymphocytes (PBL) of patients before, during, and after anesthesia and in controls. DNA single strand breaks were detected in PBL of malignant breast cancer diagnosed patients (stage II–III), who were undergoing mastectomy. Blood samples were taken before the induction of anesthesia, at 120 min of SVF anesthesia, and on the postoperative fifth day. The nuclear spreading factor (NSF) for each cell was assessed by alkaline halo assay, and the total comet score (TCS) was evaluated by comet assay. A statistically significant increase ( P < 0.0001) was observed in the mean NSF at 120 min of anesthesia (38.24 ± 14.14) as compared with samples before anesthesia (12.33 ± 6.14), and the mean NSF was significantly decreased after the postoperative fifth day (17.89 ± 9.44). Similar results were obtained by the comet assay with significant increase ( P < 0.0001) in DNA damage at 120 min of anesthesia (79.66 ± 15.28) as compared with samples before anesthesia (36.30 ± 11.39). The DNA damage was almost with the preoperative damage rates after the fifth day of anesthesia (43.40 ± 12.19). In conclusion, the study points out a reversible genotoxic effect of SVF and the similar DNA damage levels obtained by comet and alkaline halo assay indicate that although halo assay has a completely different principle, it can conveniently be utilized for the assessment of DNA single strand breakage in individual mammalian cells with its experimental advantages.

Weight of evidence: a review of concept and methods

"Weight of evidence" (WOE) is a common term in the published scientific and policy-making literature, most often seen in the context of risk assessment (RA). Its definition, however, is unclear. A systematic review of the scientific literature was undertaken to characterize the concept. For the years 1994 through 2004, PubMed was searched for publications in which "weight of evidence" appeared in the abstract and/or title. Of the 276 papers that met these criteria, 92 were selected for review: 71 papers published in 2003 and 2004 (WOE appeared in abstract/title) and 21 from 1994 through 2002 (WOE appeared in title). WOE has three characteristic uses in this literature: (1) metaphorical, where WOE refers to a collection of studies or to an unspecified methodological approach; (2) methodological, where WOE points to established interpretative methodologies (e.g., systematic narrative review, meta-analysis, causal criteria, and/or quality criteria for toxicological studies) or where WOE means that "all" rather than some subset of the evidence is examined, or rarely, where WOE points to methods using quantitative weights for evidence; and (3) theoretical, where WOE serves as a label for a conceptual framework. Several problems are identified: the frequent lack of definition of the term "weight of evidence," multiple uses of the term and a lack of consensus about its meaning, and the many different kinds of weights, both qualitative and quantitative, which can be used in RA. A practical recommendation emerges: the WOE concept and its associated methods should be fully described when used. A research agenda should examine the advantages of quantitative versus qualitative weighting schemes, how best to improve existing methods, and how best to combine those methods (e.g., epidemiology's causal criteria with toxicology's quality criteria).