The accumulation of free fatty acids induces lipotoxicity in neural cells. Estrogen, 17β-estradiol (E2) protects against the damage of cells in various organs and tissues. However, the role of E2 on lipotoxicity in neural cells remains unclear. In this study, we investigated the effects of E2 on stearic acid (saturated fatty acid)- and oleic acid (unsaturated fatty acid)-induced cytotoxicity in retinoic acid-induced mouse neuroblastoma Neuro-2a differentiated into neural cells. Cell viability was evaluated by lactate dehydrogenase release from Neuro-2a neural cells. Stearic acid and oleic acids suppressed the cell viability in a dose-dependent manner. E2 prevented oleic acid-induced cytotoxicity but had no effect on stearic acid-induced cytotoxicity. ERα-selective agonist prevented cytotoxicity in Neuro-2a neural cells. In contrast, ERβ-selective agonist slightly significantly enhanced the cytotoxicity in the presence of oleic acid. Oleic acid, but not stearic acid, increased the mRNA level of p62/Sqstm1. E2 treatment statistically significantly, but slightly, enhanced the stearic acid-induced Bax expression. In contrast, E2 and ERα-selective agonist inhibited the oleic acid-induced the p62/Sqstm1 expression. Our results suggested that fatty acids induced cytotoxicity in Neuro-2a neural cells, and estrogen prevented the oleic acid-induced cytotoxicity via ERα, but not ERβ. Further studies are needed to understand the role of ERβ in neuron injury under normal conditions.

The purpose of this study was to profile cytokine storms (cytokine release syndrome) in the LPS-induced disseminated intravascular coagulation (DIC)-cynomolgus monkey model by measuring changes in 22 cytokines using Luminex. In this study, increases were noted in 20 cytokines, excluding IL-4 and IL-17A. Specifically, IL-6, IL-8, G-CSF and TNF-α, pro-inflammatory cytokines, and IL-10, an anti-inflammatory cytokine, as well as MCP-1, markedly increased by 10,000 pg/mL or more. In addition to the marked increases in the pro-inflammatory cytokines IL-6 and G-CSF, the concentrations of IL-5, IL-18, IFN-γ, VEGF and IL-15 increased continuously. Also, in addition to the marked increases in the pro-inflammatory cytokine IL-8 as well as in MCP-1, the concentrations of IL-1ra, IL-2, IL-1β, IL-12/23 (p40), GM-CSF and TGF-α gradually decreased after initially increasing. On the other hand, in addition to the marked increases in the pro-inflammatory cytokine TNF-α and anti-inflammatory cytokine IL-10, MIP-1β and MIP-1α transiently increased and then rapidly disappeared from serum. IL-13 increased at 6 hr after administration only. Since the behavior of cytokines in this monkey model was similar to those noted in DIC in humans, this model will be useful for evaluating the efficacy of anti-DIC drugs. In addition, this model will also be useful for assessing the risk of cytokine storm development, which is a serious adverse effect of certain types of antibody drugs and CAR-T cell-based therapies.

5-Fluorocytosine (5-FC) is an antimycotic and teratogenic compound. Oral administration of 5-FC to pregnant rats on gestation days (GD) 9 and 13 was shown to induce thoracolumbar supernumerary ribs (TSR, 14th rib) and abnormal digits, respectively, in fetuses. This study investigated the effects of 5-FC on homeobox genes, which control the anterior-posterior-axis. 5-FC (75 mg/kg) was administered orally on GD9 and GD13, and tissues collected from cranial and caudal regions of TSR sites were analyzed. Following 5-FC administration on GD9, the levels of expression of Hoxa10, which determine the position of the thoracic and lumbar vertebrae, were decreased at GD13. Analysis of hindlimbs 6 hours after administration on GD13 showed decreases in expression of Hoxa11, Hoxd12, and Hoxd13, the Hox genes responsible for limb formation from the proximal to distal, and from the anterior to posterior directions. The present findings showed that altered expression of Hox genes contributes to 5-FC teratogenicity.

Measurement of the bone length is not used routinely in toxicity studies but used to examine growth and bone toxicity. To investigate the utility of measuring the bone length in toxicity studies and to identify the appropriate site, we evaluated femur, tibia, humerus, and sternum, in a 14-day repeated dose oral toxicity study of Dexamethasone (DEX), which is known to cause growth retardation and osteoporosis, in young, periadolescent, and adult rats. To observe the effect of decreased food consumption, we also evaluated the changes in each diet-restricted group in which the food intake restricted to levels corresponding to that consumed by the DEX-treated periadolescent and adult rats. Significant decreases of the bone length at all the measured sites and histopathological findings in growth plates and/or trabecular bone were observed in the DEX-treated young and periadolescent rats. Significant decreases of the femoral length and decreased trabecular bone were observed in the DEX-treated adult rats. No histopathological changes were observed in any of the diet-restricted groups, while decreases of the femoral length, similar to that in the DEX-treated adult rats were observed in the diet-restricted adult rats. The results suggested that measurement of the bone length in femur, tibia, humerus, and sternum was useful in young and periadolescent rats, and measurement of the femoral length was useful in adult rats. Moreover, our results showed that the decreases in the femoral length in the DEX-treated adult rats were not only related to the DEX-treatment, but were also influenced by the decreased food consumption.

Arsenic is an environmental pollutant and is a possible risk factor for vascular diseases such as atherosclerosis. Vascular proteoglycans (PGs) are key molecules in the initiation and progression of atherosclerosis. We previously demonstrated that arsenite, but not arsenate, decreases the synthesis of both heparan sulfate proteoglycans (HSPGs) and chondroitin/dermatan sulfate proteoglycans (CS/DSPGs) in cultured vascular endothelial cells. In the present study, we aimed to identify the PG molecules whose expression is decreased by arsenite, using a culture system of bovine aortic endothelial cells. The results indicate that a 24-hr treatment of arsenite significantly decreases the mRNA levels of a large HSPG perlecan, small HSPGs—syndecan-1, -2 and -3—, and a small CS/DSPG biglycan in vascular endothelial cells without nonspecific cell damage; the expression of syndecan-4 mRNA was unaffected by arsenite. The decreased expression of perlecan, syndecan-1 and biglycan genes began after 3 hr of arsenite treatment. However, arsenate did not change the mRNA expression levels of perlecan and biglycan in the cells. These results suggest that the inhibition of synthesis by arsenite occurs in particular types of proteoglycans, i.e. perlecan, syndecan-1, -2, -3, and biglycan in vascular endothelial cells.

In the inhalation field, lipids such as egg phosphatidylcholine (PC), 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC) and dipalmitoylphosphatidylcholine (DPPC), are considered to be generally recognized as safe (GRAS), comprising materials that are endogenous to the lungs and locally present in large quantities. Indeed, PC, DSPC and DPPC may be used to form liposomes which are known to promote an increase in drug retention time and reduce the toxicity of drugs after administration. Unfortunately, published literature guidance about the safety evaluation of these lipids as pharmaceutical excipients for use in inhaled products and about application for marketing authorization, is very limited. The purpose of this article is to review the potential toxicity of DSPC for pulmonary administration. Given the use of air and vehicle controls in a range of inhalation toxicology studies as well as negative genotoxicity and also reproductive toxicity results, it is thought that the use of DSPC is shown to be safe for pulmonary administration.