International Journal of Toxicology最新文献

The Expert Panel for Cosmetic Ingredient Safety (Panel) reviewed the safety of 9 vanilla-derived ingredients as used in cosmetics. These ingredients are reported to function mostly as skin conditioning agents in cosmetic products. Because final product formulations may contain multiple botanicals, each containing the same constituents of concern, formulators are advised to be aware of these constituents, and to avoid reaching levels that may be hazardous to consumers. Industry should continue to use good manufacturing practices to limit impurities. The Panel reviewed data relating to the safety of these ingredients and concluded that 7 ingredients are safe in cosmetics in the present practices of use and concentration when formulated to be non-sensitizing. The Panel further concluded that the available data are insufficient to make a determination of safety under the intended conditions of use in cosmetic formulations for Vanilla Planifolia Flower Extract and Vanilla Planifolia Leaf Cell Extract.

The Expert Panel for Cosmetic Ingredient Safety (Panel) assessed the safety of Basic Brown 17, which is reported to function as a hair dye in cosmetic products. The Panel reviewed the available data to determine the safety of this ingredient. The Panel concluded that Basic Brown 17 is safe in the present practices of use and concentration described in this safety assessment for use in hair dye products, and that the available data are insufficient to make a determination that Basic Brown 17 is safe under the intended conditions of use in other types of cosmetic products.

The Expert Panel for Cosmetic Ingredient Safety (Panel) reviewed the safety of 4 Scutellaria baicalensis-derived ingredients in cosmetic products; these ingredients are reported to have the following functions in cosmetics: antimicrobial agent, skin conditioning agent, abrasives, fragrance ingredients, skin protectants, and antioxidants. The Panel reviewed relevant data relating to the safety of these ingredients in cosmetic formulations, and concluded that Scutellaria Baicalensis Root Extract and Scutellaria Baicalensis Root Powder are safe in cosmetics in the present practices of use and concentration described in this safety assessment. The Panel also concluded that the available data are insufficient to make a determination of safety for Scutellaria Baicalensis Extract and Scutellaria Baicalensis Sprout Extract under the reported conditions of use in cosmetic formulations.

It has been said that "too much confidence cannot be placed on the lessons of history." We suggest that this declaration is particularly salient for the dynamic field of toxicology. The intersection of historical trends and technological developments within and outside the discipline is briefly considered as they have shaped what we study and what we do. Most importantly, perhaps, both individually and collectively, these elements also highlight cautions and define challenges that toxicology must embrace to continue to thrive and contribute to the scientific enterprise and public health.

N-trans-caffeoyltyramine (NCT) is a phenolic hydroxycinnamic acid amide naturally present in many plant crop species and is associated with immune response and many development processes. Little research has been done on the potential safety of NCT for use as an ingredient in conventional foods and beverages. This study assessed the safety of NCT derived from caffeic acid and produced using a genetically engineered strain Yarrowia lipolytica strain 3599_7 via precision fermentation through in vitro genotoxicity assays and a 90-day dietary oral toxicity study in rats. The Ames test was performed in bacterial strains and the highest dose tested was 5000.0 μg/plate in the presence and absence of S9. The in vitro mammalian micronucleus test was conducted in human peripheral blood lymphocytes in culture exposed to NCT at predetermined concentrations in the absence (4-hour and 24-hour exposure) and presence (4-hour exposure) of S9. NCT was not genotoxic as evident from the Ames and the in vitro micronucleus assay. NCT exhibited no adverse effects in the 90-day oral toxicity study up to the highest dose tested, where the no-observed-adverse-effect level was 1427 and 1983 mg/kg body weight/day in males and females, respectively.

Various types of vehicles are used in non-clinical studies to administer treatment substances to experimental animals. It is recognized that these vehicle substances can influence animal physiology to some extent. Studies are designed to minimize the effects of vehicle substances to ensure reliable results. However, research on the biological effects of these vehicles is still inadequate. This study aims to assess the effects of vehicles on selected biological parameters (body weight, food consumpton, water consumption, functional observational battery, clinical pathology, and organ weights) and to establish reference ranges for these parameters to aid in historical control data. A total of 1,528 Sprague-Dawley rats were used in this study, exposed to commonly utilized vehicles such as distilled water, corn oil, dimethyl sulfoxide (DMSO), polyethylene glycol 400, carboxymethyl cellulose, and methyl cellulose via oral dosing at 5 mL/kg body weight per day, consistent with the dosing regimen employed in the toxicity tests included in this study. Significant changes were observed in the red blood cell counts and organ weights with DMSO treatment, whereas other vehicles induced only minor changes. This study highlights the importance of careful vehicle selection in non-clinical trials to eliminate their biological impact.

Dimethyl sulfoxide (DMSO) is commonly used as a solvent for preparing amyloid-beta (Aβ) peptides implicated in Alzheimer's disease. While considered relatively non-toxic at low concentrations, DMSO itself may exert biological effects that could confound experimental outcomes, especially for weakly cytotoxic substances like Aβ. Seven brain cell types (BV-2, N2a, SH-SY5Y, U87, neurons, astrocytes, microglia) were treated with varying DMSO concentrations or Aβ1-42 oligomers/protofibrils/fibrils prepared using DMSO. Cell viability was assessed by CCK-8 and LDH assays. Matched DMSO controls were prepared alongside Aβ treatments to delineate solvent effects. Low DMSO concentrations (0.0625-0.015625%) exhibited hormetic cytoprotective and growth-promoting effects, while higher concentrations (≥2%) were cytotoxic. Importantly, these hormetic solvent effects confounded the measurement of Aβ cytotoxicity. By accounting for matched DMSO controls, the study revealed that Aβ fibril toxicity may have been underestimated due to the cytoprotective solvent effects of low DMSO concentrations used in their preparation. In conclusion, DMSO exhibits complex hormetic dose-responses that can significantly influence experimental outcomes, especially for weakly cytotoxic agents like Aβ. Rigorous solvent controls are crucial to delineate genuine substance effects from potential solvent confounds and avoid erroneous interpretations.

Sulfur mustard (SM) is a highly toxic bifunctional alkylating agent that inflicts severe damage on the respiratory tract. Although numerous studies have examined the mechanisms underlying SM-induced pulmonary injury, the exact pathways involved remain unclear. This study aims to investigate an acute pulmonary injury model, with SM administered as a single intraperitoneal injection (8 mg/kg) or single intratracheal instillation (2 mg/kg) at equal toxicity doses (1LD50). The results revealed that epithelial cells in the alveolar septa of the intraperitoneal SM group exhibited a significantly higher expression of apoptotic markers, including pro-apoptotic protein Bax, caspase-3, and caspase-9 proteins, than those in the tracheal SM group. Conversely, the expression of the anti-apoptotic protein Bcl-2 was significantly lower in the intraperitoneal SM group than in the tracheal SM group, as confirmed by TUNEL staining and immunohistochemical staining. The intraperitoneal SM group exhibited markedly higher expression of fibrosis-related proteins, including MMP-2, MMP-9, TIMP-1, TIMP-2, collagen type I, collagen type III, TGF-β1, and Smad7, than the tracheal SM group. These markers, detected through immunohistochemical immunolabeling, indicate a more significant fibrotic response in the intraperitoneal group. In summary, this study demonstrates that intraperitoneal exposure to SM results in increased apoptosis, elevated expression of pro-apoptotic proteins, and fibrosis-related proteins in the alveolar epithelial cells compared with intratracheal exposure, even at equivalent toxicity levels. Our findings highlight the suitability of the intraperitoneal route for further investigation and identify apoptotic and fibrosis-related proteins as potential targets for intervention in SM-induced pulmonary injury.

Paroxysmal supraventricular tachycardia (PSVT) is a common cardiac arrhythmia associated with substantial health care burden. Etripamil, a fast-acting non-dihydropyridine calcium channel blocker developed for intranasal self-administration, is currently under investigation for acute treatment of PSVT episodes. A novel two-phase study design was used to test a series of five doses of intravenous etripamil (0, 0.025, 0.05, 0.15, and 0.3 mg/kg) in conscious cynomolgus monkeys. The cardiovascular effects (e.g., blood pressure and ECG recordings) were assessed during the first phase, and the pharmacokinetic profile was characterized during the second phase. Animals were dosed remotely to avoid the stress of intranasal dosing and minimize the impact of dose administration on measurements. Results were compared with findings from subsequent intranasal studies in cynomolgus monkeys and humans. Etripamil decreased systolic blood pressure and increased heart rate proportionately in a dose-dependent manner. Etripamil also induced dose-dependent increases in the PR interval. At a dose of 0.3 mg/kg (the highest dose), the mean highest PR prolongation from baseline during 20 minutes after dosing was 27.38%. Systemic exposure to etripamil increased in a dose-dependent manner. Mean area under the curve from administration to when drug was no longer present (AUC_0-∞) values ranged from 179 to 2364 ng • min/mL, peak plasma concentration ranged from 13.2 to 176 ng/mL, and mean half-life ranged from 12.3 to 20.8 minutes (Figure 1). Results were consistent with data from subsequent intranasal preclinical and clinical studies. Intravenous etripamil demonstrated the desired targeted pharmacokinetic and pharmacodynamic profiles in conscious cynomolgus monkeys.

Aficamten (CK-3773274) is a cardiac myosin inhibitor in development for the treatment of hypertrophic cardiomyopathy (HCM), a commonly inherited heart condition often characterized as a disease of the sarcomere. Aficamten reduces pathologic cardiac hypercontractility by selectively binding to an allosteric site on cardiac myosin. To characterize the pharmacology and toxicology of aficamten, a series of nonclinical repeated dose studies were conducted. In a 10-day repeated dose pharmacology study in Sprague Dawley rats, aficamten produced dose-dependent reductions in left ventricular fractional shortening (FS) which were fully reversible within 24 h. Aficamten did not change the ratio of heart weight to tibia length (HW/TL) or left ventricular posterior wall (LVPW) thickness at any dose tested. At a supratherapeutic dose of 6 mg/kg/day, there was a significant increase in interventricular septum (IVS) thickness. Aficamten did not affect mRNA expression of the cardiac injury biomarkers BNP, β-MHC, or ANP. In repeated dose Good Laboratory Practice (GLP) regulatory toxicology studies in Sprague Dawley rats for up to 6 months and beagle dogs for up to 9 months, the primary adverse findings at supratherapeutic doses were consistent across all studies and observed in the heart consisting of atrial/ventricular dilatation that correlated with increased heart weights. These findings were largely reversible and consistent with excessive on-target pharmacology associated with cardiac myosin inhibition. The reversible nature of aficamten-associated adverse effects is supportive of its clinical safety as this property suggests that these findings, should they occur in humans, may also be reversible, limiting long-term human cardiac risk.