Associations between prenatal exposure to per- and polyfluoroalkyl substances and plasma immune molecules in three-year-old children in China.

BACKGROUND: Many studies have reported that prenatal exposure to Per- and Polyfluoroalkyl Substances (PFASs) can disrupt immune function. However, little is known about the effects of PFASs on immune molecules. The study analyzed the association between prenatal exposure to mixed and single PFASs and plasma immune molecules in three-year-old children. METHODS: Ten PFASs were measured in umbilical cord serum, while peripheral blood samples were collected at age three to measure immune molecules. Associations between exposure to individual and combined PFASs and immune molecules were analyzed using Generalized Linear Models and Weighted Quantile Sum (WQS) regression. RESULTS: (1) Interleukin-4 (IL-4) increased by 23.85% (95% CI:2.99,48.94) with each doubling of Perfluorooctanoic Acid (PFOA), and Interleukin-6 (IL-6) increased by 39.07% (95%CI:4.06,85.86) with Perfluorotridecanoic Acid (PFTrDA). Elevated PFOA and Perfluorononanoic Acid (PFNA) were correlated with increases of 34.06% (95% CI: 6.41, 70.28) and 24.41% (95% CI: 0.99, 53.27) in Eotaxin-3, respectively. Additionally, the doubling of Perfluorohexane Sulfonic Acid (PFHxS) was associated with a 9.51% decrease in Periostin (95% CI: -17.84, -0.33). (2) The WQS analysis revealed that mixed PFASs were associated with increased IL-6 (ß = 0.37, 95%CI:0.04,0.69), mainly driven by PFTrDA, PFNA, and 8:2 Chlorinated Perfluoroethyl Sulfonamide (8:2 Cl-PFESA). Moreover, mixed PFASs were linked to an increase in Eotaxin-3 (ß = 0.32, 95% CI: 0.09,0.55), primarily influenced by PFOA, PFTrDA, and Perfluorododecanoic Acid (PFDoDA). CONCLUSIONS: Prenatal PFASs exposure significantly alters the levels of immune molecules in three-year-old children, highlighting the importance of understanding environmental impacts on early immune development.

Safety assessment of cosmetics by read across applied to metabolomics data of in vitro skin and liver models.

As a result of the cosmetics testing ban, safety evaluations of cosmetics ingredients must now be conducted using animal-free methods. A common approach is read across, which is mainly based on structural similarities but can also be conducted using biological endpoints. Here, metabolomics was used to assess biological effects to enable a read across between a candidate cosmetic ingredient, DIV665, only studied using in vitro assays, and a structurally similar reference compound, PA102, previously investigated using traditional in vivo toxicity methods. The (1) cutaneous distribution after topical application, (2) skin metabolism, (3) liver metabolism and (4) effect on the intracellular metabolomic profiles of in vitro skin and hepatic models, SkinEthic®RHE model and HepaRG® cells were investigated. The compounds exhibited similar skin penetration and skin and liver metabolism, with small differences attributed to their physicochemical properties. The effects of both compounds on the metabolome of RHE and HepaRG® cells were similarly small, both in terms of the metabolites modulated and the magnitude of changes. The patterns of metabolome changes did not fit with any known signature relating to a mode of action known to be linked to liver toxicity e.g. modification of the Krebs cycle, urea synthesis and lipid metabolism, were more reflective of transient adaptive responses. Overall, these studies indicate that PA102 is biologically similar to DIV665, allowing read across of safety endpoints, such as in vivo sub-chronic (but not reproduction toxicity) studies, for the former to be applied to DIV665. Based on this, in the absence of animal data (which is prohibited for new chemicals), it could be concluded that DIV665 applied according to the consumer topical use scenario, is similar to PA102, and is predicted to exhibit low local skin and systemic toxicity.

Perfluoroalkyl acids and their isomers, diabetes, anemia, and albuminuria: Variabilities with deteriorating kidney function.

Data for US adults aged ≥20 years from National Health and Nutrition Examination Survey for the years 2003-2014 were analyzed to evaluate how adjusted (N = 8481) and unadjusted (N = 9080) levels of selected perfluoroalkyl acids (PFAA) vary across the different stages of glomerular function (GF) among those who did not have diabetes, anemia, or albuminuria as compared to those who had diabetes only, anemia only, and albuminuria only. PFAAs selected for analyses were: perfluorooctanoic acid (PFOA), perfluorooctane sulfonic acid (PFOS), perfluorodecanoic acid (PFDA), perfluorohexane sulfonic acid (PFHxS), and perfluorononanoic acid (PFNA). Irrespective of GF stage, there was no noticeable evidence to suggest that adjusted levels of PFAA for those with diabetes only are any lower than those with no diabetes, no anemia, and no albuminuria. Those who had anemia only were found to have lower adjusted levels of at least PFOA, PFOS, PFDA, and PFHxS than those who had no diabetes, no anemia, and no albuminuria. These results were seen in the presence (eGFR < 60 mL/min/1.73 m2) as well as the absence of chronic kidney disease. For GF-1 (eGFR > 90 mL/min/1.73 m2), GF-2 (60 ≤ eGFR ≤ 90 mL/min/1.73 m2), and GF-3B/4 (15 < eGFR ≤ 45 mL/min/1.73 m2), those who had albuminuria only had lower adjusted levels of PFOA, PFOS, and PFHxS than those who had no diabetes, no anemia, and no albuminuria. In general, adjusted levels of those who had albuminuria only were lower than those who had anemia only at GF-3 and more often than not at GF-1 and GF-2. Rise in adjusted levels of PFAA from GF-1 to GF-3A (45 < eGFR < 60 mL/min/1.73 m2) was faster for those with anemia only than any other comparison group for the total population and females.

Prenatal exposure to perfluorodecanoic acid is associated with lower circulating concentration of adrenal steroid metabolites during mini puberty in human female infants. The Odense Child Cohort.

BACKGROUND: Fetal programming of the endocrine system may be affected by exposure to perfluoroalkyl substances (PFAAs), as they easily cross the placental barrier. In vitro studies suggest that PFAAs may disrupt steroidogenesis. "Mini puberty" refers to a transient surge in circulating androgens, androgen precursors, and gonadotropins in infant girls and boys within the first postnatal months. We hypothesize that prenatal PFAA exposure may decrease the concentrations of androgens in mini puberty. OBJECTIVES: To investigate associations between maternal serum PFAA concentrations in early pregnancy and serum concentrations of androgens, their precursors, and gonadotropins during mini puberty in infancy. METHODS: In the prospective Odense Child Cohort, maternal pregnancy serum concentrations of five PFAAs: Perfluorohexane sulfonic acid (PFHxS), perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), and perfluorodecanoic acid (PFDA) were measured at median gestational week 12 (IQR: 10, 15) in 1628 women. Among these, offspring serum concentrations of dehydroepiandrosterone (DHEA), dehydroepiandrosterone-sulfate (DHEAS), androstenedione, 17-hydroxyprogesterone (17-OHP), testosterone, luteinizing (LH) and follicle stimulating hormones (FSH) were measured in 373 children (44% girls; 56% boys) at a mean age of 3.9 (±0.9 SD) months. Multivariate linear regression models were performed to estimate associations. RESULTS: A two-fold increase in maternal PFDA concentration was associated with a reduction in DHEA concentration by -19.6% (95% CI: -32.9%, -3.8%) in girls. In girls, also, the androstenedione and DHEAS concentrations were decreased, albeit non-significantly (p < 0.11), with a two-fold increase in maternal PFDA concentration. In boys, no significant association was found between PFAAs and concentrations of androgens, their precursors, and gonadotropins during mini puberty. CONCLUSION: Prenatal PFDA exposure was associated with significantly lower serum DHEA concentrations and possibly also with lower androstenedione and DHEAS concentrations in female infants at mini puberty. The clinical significance of these findings remains to be elucidated.

Toxicokinetics of perfluorohexanoic acid (PFHxA), perfluorooctanoic acid (PFOA) and perfluorodecanoic acid (PFDA) in male and female Hsd:Sprague dawley SD rats following intravenous or gavage administration.

Poly- and perfluorinated alkyl substances (PFAS) are environmentally persistent chemicals associated with many adverse health outcomes. The National Toxicology Program evaluated the toxicokinetics (TK) of several PFAS to provide context for toxicologic findings.Plasma TK parameters and tissue (liver, kidney, brain) concentrations are reported for perfluorohexanoic acid (PFHxA), perfluorooctanoic acid (PFOA) or perfluorodecanoic acid (PFDA) after single-dose administration in male and female Hsd:Sprague-Dawley® (SD) rats.Generally, longer Tmax and elimination half-lives, and slower clearance f, were correlated with longer chain length. Male rats administered PFOA had a prolonged half-life compared to females (215 h vs. 2.75), while females had faster clearance and smaller plasma area under the curve (AUC). Females administered PFHxA had a shorter half-life (2 h vs. 9) than males and faster clearance with a smaller plasma AUC, although this was less pronounced than PFOA. There was no sex difference in PFDA half-life. Female rats administered PFDA had a higher plasma AUC/dose than males, and a slower clearance. PFDA had the highest levels in the liver of the PFAS evaluated.Profiling the toxicokinetics of these PFAS allows for comparison among subclasses, and more direct translation of rodent toxicity to human populations.

Exploring sex differences in human health risk assessment for PFNA and PFDA using a PBPK model.

Perfluorononanoic acid (PFNA) and perfluorodecanoic acid (PFDA), which are classified as perfluoroalkyl and polyfluoroalkyl substances (PFASs), have been widely used in industrial applications as a surface protectant. PFASs have been detected in wildlife and in humans around the globe. The purposes of this study are to develop and validate a physiologically based pharmacokinetic (PBPK) model for detecting PFNA and PFDA in male and female rats, and to apply the model to a human health risk assessment regarding the sex difference. A PBPK model of PFNA and PFDA was established based on an in vivo study in male and female rats. Analytes in biological samples (plasma, nine tissues, urine, and feces) were determined by ultra-liquid chromatography coupled tandem mass spectrometry (UPLC-MS/MS) method. PFNA and PFDA showed a gender differences in the elimination half-life and volume of distribution. The tissue-plasma partition coefficients were the highest in the liver in both male and female rats. The predicted rat plasma and urine concentrations simulated and fitted were in good agreement with the observed values. The PBPK models of PFNA and PFDA in male and female rats were then extrapolated to a human PBPK model based on human physiological parameters. The external doses were calculated at 3.35 ng/kg/day (male) and 17.0 ng/kg/day (female) for PFNA and 0.530 ng/kg/day (male) and 0.661 ng/kg/day (female) for PFDA. Human risk assessment was estimated using Korean biomonitoring values considering the gender differences. This study provides valuable insight into human health risk assessment regarding PFNA and PFDA exposure.

Perfluorodecanoic acid-induced oxidative stress and DNA damage investigated at the cellular and molecular levels.

Perfluorodecanoic acid (PFDA) has been widely used in production of many daily necessities because of its special nature. Althoughtoxic effects of PFDA to organisms have been reported, there is little research on the genotoxicity induced by oxidative stress of PFDA on the cellular and molecular levels simultaneously. Thus, we investigated the DNA oxidative damage caused by PFDA in mouse hepatocytes. On the cellular level, an increase in ROS content indicated that PFDA caused oxidative stress in mouse hepatocytes. In addition, after PFDA exposure, the comet assay confirmed DNA strand breaks and an increased 8-OHdG content demonstrated DNA oxidative damage. On the molecular level, the microenvironment of aromatic amino acids, skeleton and secondary structure of catalase (CAT) were varied after PFDA exposure and the enzyme activity was reduced because PFDA bound near the heme groups of CAT. Moreover, PFDA was shown to interact with DNA molecule by groove binding. This study suggests that PFDA can cause genotoxicity by inducing oxidative stress both on the cellular and molecular levels.

Decanoic acid suppresses proliferation and invasiveness of human trophoblast cells by disrupting mitochondrial function.

Decanoic acid (DA) is a medium-chain fatty acid used in the manufacture of various products including plastics, cosmetics, and lubricants. In addition to antiviral and antibacterial effects, DA's, reported biological activities include regulation of signaling pathways and redox homeostasis in various human cell types. The influence of DA on functional properties of human trophoblasts, including proliferation, invasion and apoptosis is currently unknown. In the present study, we evaluated the anti-proliferative and anti-invasive effects of DA on the human trophoblast cell line HTR8/SVneo. In addition, DA induced oxidative stress, as evidenced by generation of reactive oxygen species (ROS) and induction of lipid peroxidation (LPO). This oxidative stress was accompanied by activation of the mitochondria-dependent apoptotic pathway in HTR8/SVneo cells. We also observed elevated mitochondrial Ca2+, and loss of mitochondrial membrane potential in response to DA treatment. Chelation of mitochondrial Ca2+ using BAPTA-AM rescued cellular proliferation suppressed by DA. We also verified that signaling proteins including AKT, P70S6K, S6, and ERK1/2 and their targets were significantly reduced in HTR8/SVneo cells by DA treatment. Pre-treatment of cells with selective inhibitors of AKT (LY294002) and ERK1/2 (U0126) revealed that the AKT and ERK1/2 signaling pathways regulated by DA displayed cross-talk in HTR8/SVneo cells. Collectively, these results suggest that personal products containing DA will have harmful effects on human trophoblasts, and could cause implantation and placentation failure during early pregnancy.

An Aliphatic Ester Diisopropyl Sebacate Exhibited an Adjuvant Effect on Fluorescein Isothiocyanate-Induced Contact Hypersensitivity Mouse Models.

Alternative plasticizers have become more popular due to health concerns about phthalate esters. We demonstrated that phthalate esters enhanced skin sensitization to fluorescein isothiocyanate (FITC) in mouse contact hypersensitivity models. Alternative plasticizers have not been well studied as to their effect on the immune system. We previously found that diisopropyl adipate (DIPA), an aliphatic dicarboxylic acid ester, enhanced skin sensitization to FITC. Sebacate esters are also widely used as alternative plasticizers. Here we tested diisopropyl sebacate (DIPS), which has the same alcohol with an aliphatic dicarboxylic acid of longer chain, using BALB/c mice. The results showed that DIPS facilitated skin sensitization to FITC and increased FITC-presenting dendritic cell trafficking from the skin to draining lymph nodes. Furthermore, DIPS activated transient receptor potential ankyrin 1 (TRPA1). The latter feature has been commonly observed for phthalate esters and DIPA, which have adjuvant effects. In summary, the adjuvant effect of a sebacate ester was demonstrated in a mouse model.

Perfluoroalkyl acid exposure induces protective mitochondrial and endoplasmic reticulum autophagy in lung cells.

Wide application of perfluoroalkyl acids (PFAAs) has raised great concerns on their side-effects on human health. PFAAs have been shown to accumulate mainly in the liver and cause hepatotoxicity. However, PFAAs can also deposit in lung tissues through air-borne particles and cause serious pulmonary toxicity. But the underlying mechanisms are still largely unknown. Autophagy is a type of programmed cell death parallel to necrosis and apoptosis, and may be involved in the lung toxicity of PFAAs. In this study, lung cancer cells, A549, were employed as the model to investigate the effects of three PFAAs with different carbon chain lengths on cell autophagy. Through Western blot analysis on LC3-I/II ratio of cells exposed to non-cytotoxic concentration (200 µM) and cytotoxic concentration (350 µM), we found concentration-dependent increase of autophagosomes in cells, which was further confirmed by TEM examination on ultra-thin section of cells and fluorescence imaging on autophagosomes in live cells. The abundance of p62 increased with the PFAAs concentration indicating the blockage of autophagy flux. Furthermore, we identified the mitochondrial autophagy (mitophagy) and endoplasmic reticulum autophagy (ER-phagy) morphologically as the major types of autophagy, suggesting the disruption on mitochondria and ERs. These organelle damages were confirmed by the overgeneration of ROS, hyperpolarization of mitochondrial membrane potential, as well as the up-regulation of ER-stress-related proteins, ATF4 and p-IRE1. Further analysis on the signaling pathways showed that PFAAs activated the MAPK pathways and inhibited the PI3K/Akt pathway, with potencies following the order of PFDA > PFNA > PFOA. Anti-oxidant (NAC) treatment did not rescue cells from death, indicating that oxidative stress is not the reason of cytotoxicity. Inhibition of autophagy by Atg5 siRNA and chloroquine even increased the toxicity of PFAAs, suggesting that PFAAs-autophagy was induced as the secondary effects of organelle damages and played a protective role during cell death.

Correlation between mast cell-mediated allergic inflammation and length of perfluorinated compounds.

Perfluorinated compounds (PFC) have widely been used in numerous applications including clothing, food packaging, and nonstick coating. With the widespread use of PFC, concerns regarding potential adverse health effects in humans and wildlife have increased. In spite of the known PFC-mediated immunotoxiciy, correlation with PFC and allergic inflammation still requires elucidation. The aim of this study was to examine the effect of four types of PFC (perfluoroheptanoic acid [PFHpA], perfluorononanoic acid [PFNA], perfluorodecanoic acid [PFDA], and perfluoroundecanoic acid [PFUnA]) on mast cell-mediated allergic inflammation in the presence of high-affinity immunoglobulin (Ig) E receptor (FcεRI) cross-linking. Among PFC family, long-chain PFDA and PFUnA increased release of histamine and ß-hexosaminidase by up-regulation of intracellular calcium levels in IgE-stimulated mast cells. In addition, PFDA and PFUnA enhanced gene expression of pro-inflammatory cytokines, such as tumor necrosis factor (TNF)-α, interleukin (IL)-1ß, IL-6, and IL-8 by activation of nuclear factor-κB in IgE-stimulated mast cells. In ovalbumin (OVA)-induced model of systemic anaphylaxis in the presence of hypothermia, PFNA, PFDA, and PFUnA exacerbated allergic symptoms accompanied by elevation in serum histamine, TNF-α, IgE, and IgG1. Our data indicate that some PFC aggravated high-affinity IgE receptor (FcεRI)-mediated mast cell degranulation and allergic symptoms. Consequently, the results demonstrated that carbon-chain length of PFC may serve as a factor in allergic inflammation.

Translational safety biomarkers of colonic barrier integrity in the rat.

The intestinal barrier controls intestinal permeability, and its disruption has been associated with multiple diseases. Therefore, preclinical safety biomarkers monitoring barrier integrity are essential during the development of drugs targeting the intestines, particularly if starting treatment early after onset of disease. Classical toxicology endpoints are not sensitive enough and therefore our objective was to identify non-invasive markers enabling early in vivo detection of colonic barrier perturbation. Male Sprague-Dawley rats were dosed intracolonically via the rectum, using sodium caprate or ibuprofen as tool compounds to alter barrier integrity. Several potentially translational biomarkers and probe molecules related to permeability, inflammation or tissue damage were evaluated, using various analytical platforms, including immunoassays, targeted metabolomics and highly sensitive ultra-performance liquid chromatography-tandem mass spectrometry. Several markers were identified that allow early in vivo detection of colonic barrier integrity changes, before histopathological evidence of tissue damage. The most promising permeability markers identified were plasma fluorescein isothiocyanate-dextran 4000 and a lactulose/mannitol/sucralose mixture in urine. These markers showed maximum increases over 100-fold or approximately 10-50-fold, respectively. Intracolonic administration of the above probe molecules outperformed oral administration and inflammatory or other biomarkers, such as α2 -macroglobulin, calprotectin, cytokines, prostaglandins and a panel of metabolic molecules to identify early and subtle changes in barrier integrity. However, optimal timing of probe administration and sample collection is important for all markers evaluated. Inclusion of these probe molecules in preclinical toxicity studies might aid in risk assessment and the design of a clinical biomarker plan, as several of these markers have translational potential.

Dual action of peroxisome proliferator-activated receptor alpha in perfluorodecanoic acid-induced hepatotoxicity.

Perfluorodecanoic acid (PFDA) is widely used in production of many daily necessities based on their surface properties and stability. It was assigned as a Persistent Organic Pollutant in 2009 and became a public concern partly because of its potential for activation of the peroxisome proliferator-activated receptor alpha (PPARα). In this study, wild-type and Ppara-null mice were administered PFDA (80 mg/kg). Blood and liver tissues were collected and subjected to systemic toxicological and mechanistic analysis. UPLC-ESI-QTOFMS-based metabolomics was used to explore the contributing components of the serum metabolome that led to variation between wild-type and Pparα-null mice. Bile acid homeostasis was disrupted, and slight hepatocyte injury in wild-type mice accompanied by adaptive regulation of bile acid synthesis and transport was observed. The serum metabolome in wild-type clustered differently from that in Pparα-null, featured by sharp increases in bile acid components. Differential toxicokinetic tendency was supported by regulation of UDP-glucuronosyltransferases dependent on PPARα, but it did not contribute to the hepatotoxic responses. Increase in Il-10 and activation of the JNK pathway indicated inflammation was induced by disruption of bile acid homeostasis in wild-type mice. Inhibition of p-p65 dependent on PPARα activation by PFDA stopped the inflammatory cascade, as indicated by negative response of Il-6, Tnf-α, and STAT3 signaling. These data suggest disruptive and protective role of PPARα in hepatic responses induced by PFDA.

New insights into the toxicity mechanism of octanoic and decanoic acids on Saccharomyces cerevisiae.

Octanoic (C8) and decanoic (C10) acids are produced in hypoxic conditions by the yeast Saccharomyces cerevisiae as by-products of its metabolism and are considered fermentation inhibitors in the presence of ethanol at acidic pH. This study aims to broaden our understanding of the physiological limits between toxicity and ester production in yeast cells. To this end, the non-inhibitory concentration (NIC) and maximum inhibitory concentration (MIC) values were first established for C8 and C10 at physiological pH (5.8) without ethanol. The results showed that when these acids were added to culture medium at these values, they tended to accumulate in different cellular fractions of the yeast. While C8 was almost entirely located in the cell wall fraction, C10 was found in the endocellular fraction. Cell fatty acid detoxification was also different; while the esterification of fatty acids was more efficient in the case of C10, the peroxisome was activated regardless of which fatty acid was added. Furthermore, the study of the Pdr12 and Tpo1 transporters that evolved during the detoxification process revealed that C8 was mostly expelled by the Pdr12 carrier, which was related to higher ß-oxidative damage in the presence of endocellular C10. C10 is more toxic at lower concentrations than C8. Although they are produced by yeast, the resulting intracellular medium-chain fatty acids (MCFAs) caused a level of toxicity which promoted cell death. However, MCFAs are involved in the production of beverage flavours.

Comparative toxicity assessment of alternative versus legacy PFAS: Implications for two primary trophic levels in freshwater ecosystems.

Perfluoroalkyl substances (PFAS) are common environmental pollutants, but their toxicity framework remains elusive. This research focused on ten PFAS, evaluating their impacts on two ecotoxicologically relevant model organisms from distinct trophic levels: the crustacean Daphnia magna and the unicellular green alga Raphidocelis subcapitata. The results showed a greater sensitivity of R. subcapitata compared to D. magna. However, a 10-day follow-up to the 48 h immobilisation test in D. magna showed delayed mortality, underlining the limitations of relying on EC50 s from standard acute toxicity tests. Among the compounds scrutinized, Perfluorodecanoic acid (PFDA) was the most toxic to R. subcapitata, succeeded by Perfluorooctane sulfonate (PFOS), Perfluorobutanoic acid (PFBA), and Perfluorononanoic acid (PFNA), with the latter being the only one to show an algicidal effect. In the same species, assessment of binary mixtures of the compounds that demonstrated high toxicity in the single evaluation revealed either additive or antagonistic interactions. Remarkably, with an EC50 of 31 mg L-1, the short-chain compound PFBA, tested individually, exhibited toxicity levels akin to the notorious long-chain PFOS, and its harm to freshwater ecosystems cannot be ruled out. Despite mounting toxicological evidence and escalating environmental concentrations, PFBA has received little scientific attention and regulatory stewardship. It is strongly advisable that regulators re-evaluate its use to mitigate potential risks to the environmental and human health.

Evaluation of poly (1, 6-bis-(p-carboxyphenoxy) hexane-co-sebacic acid microspheres for controlled basal insulin delivery.

PURPOSE: To develop poly 1,3-bis-(p-carboxyphenoxy) hexane-co-sebacic acid (p(CPH/SA)) microspheres for controlled basal insulin delivery and evaluate their in vivo efficacy and toxicity. METHODS: A series of CPH/SA copolymers with molar ratios 20/80, 40/60, and 50/50 were synthesized and characterized. The stability of encapsulated insulin and the fraction of insulin released from microspheres were assessed by different analytical techniques. The skin from the injection site of rats was examined microscopically for histomorphological changes. RESULTS: Increasing the molar ratio of CPH/SA significantly (p < 0.05) improved insulin loading and controlled insulin release. However, dimer aggregates of insulin were observed as CPH/SA molar ratio increased. Co-encapsulation of zinc oxide with insulin inhibited dimer aggregate formation and further controlled insulin release. Insulin was stable after entrapment into microspheres and during in vitro release studies. Administration of microsphere formulations CPH/SA 40/60 and 50/50 with zinc oxide controlled insulin release and maintained basal insulin levels for 42 days in rats. Skin sections showed minimal inflammation with no evidence for histomorphological changes and toxicity. CONCLUSIONS: Insulin-loaded CPH/SA microspheres demonstrated considerable potential as controlled delivery system for insulin. Copolymer microspheres maintained basal insulin levels for 42 days and were biodegradable and biocompatible.

Membrane stress caused by octanoic acid in Saccharomyces cerevisiae.

In order to compete with petroleum-based fuel and chemicals, engineering a robust biocatalyst that can convert renewable feedstocks into biorenewable chemicals, such as carboxylic acids, is increasingly important. However, product toxicity is often problematic. In this study, the toxicity of the carboxylic acids hexanoic, octanoic, and decanoic acid on Saccharomyces cerevisiae was investigated, with a focus on octanoic acid. These compounds are completely inhibitory at concentrations of magnitude 1 mM, and the toxicity increases as chain length increases and as media pH decreases. Transciptome analysis, reconstruction of gene regulatory network, and network component analysis suggested decreased membrane integrity during challenge with octanoic acid. This was confirmed by quantification of dose-dependent and chain length-dependent induction of membrane leakage, though membrane fluidity was not affected. This induction of membrane leakage could be significantly decreased by a period of pre-adaptation, and this pre-adaptation was accompanied by increased oleic acid content in the membrane, significantly increased production of saturated lipids relative to unsaturated lipids, and a significant increase in the average lipid chain length in the membrane. However, during adaptation cell surface hydrophobicity was not altered. The supplementation of oleic acid to the medium not only elevated the tolerance of yeast cells to octanoic acid but also attenuated the membrane leakiness. However, while attempts to mimic the oleic acid supplementation effects through expression of the Trichoplusia ni acyl-CoA Δ9 desaturase OLE1(TniNPVE desaturase) were able to increase the oleic acid content, the magnitude of the increase was not sufficient to reproduce the supplementation effect and increase octanoic acid tolerance. Similarly, introduction of cyclopropanated fatty acids through expression of the Escherichia coli cfa gene was not helpful for tolerance. Thus, we have provided quantitative evidence that carboxylic acids damage the yeast membrane and that manipulation of the lipid content of the membrane can increase tolerance, and possibly production, of these valuable products.

Safety of medium-chain triglycerides used as an intraocular tamponading agent in an experimental vitrectomy model rabbit.

PURPOSE: To evaluate safety of medium-chain triglycerides used as a possible intraocular tamponading agent. METHODS: A 20-gauge pars plana vitrectomy was performed in the right eye of 28 rabbits. An ophthalmologic examination was performed every week until rabbits were killed. At days 7, 30, 60, and 90, rabbits were killed and the treated eyes were examined macroscopically and prepared for histologic examination. Principal outcome was retinal toxicity evaluated by light and electron microscopy, and secondary outcomes were the presence of medium-chain triglyceride emulsification, inflammatory reactions, and the development of cataract. RESULTS: Histologic examination did not reveal any retinal toxicity. Two cases of moderate emulsification were observed, but in these cases, emulsification was caused by the perioperative injection of the agent and did not increase during the postoperative period. We noted 13 cases of inflammatory reaction in vitreous cavity and no case of inflammatory reaction in anterior chamber. Two eyes developed cataract as a result of perioperative trauma to the lens with the vitreous cutter and not secondary to the presence of medium-chain triglycerides in the vitreous cavity. CONCLUSION: Medium-chain triglycerides did not induce morphologic evidence of retinal toxicity. The results suggest that medium-chain triglycerides could be a promising alternative intraocular tamponading agent for the treatment of retinal detachments.

In vitro characterization of the immunotoxic potential of several perfluorinated compounds (PFCs).

We have previously shown that PFOA and PFOS directly suppress cytokine secretion in immune cells, with different mechanisms of action. In particular, we have demonstrated a role for PPAR-α in PFOA-induced immunotoxicity, and that PFOS has an inhibitory effect on LPS-induced I-κB degradation. These studies investigate the immunomodulatory effects of four other PFCs, namely PFBS, PFOSA, PFDA, and fluorotelomer using in vitro assays. The release of the pro-inflammatory cytokines IL-6 and TNF-α was evaluated in lipolysaccharide (LPS)-stimulated human peripheral blood leukocytes (hPBL) and in the human promyelocytic cell line THP-1, while the release of IL-10 and IFN-γ was evaluated in phytohemagglutinin (PHA)-stimulated hPBL. All PFCs suppressed LPS-induced TNF-α production in hPBL and THP-1 cells, while IL-6 production was suppressed by PFOSA, PFOS, PFDA and fluorotelomer. PFBS, PFOSA, PFOS, PFDA and fluorotelomer inhibited PHA-induced IL-10 release, while IFN-γ secretion was affected by PFOSA, PFOS, PFDA and fluorotelomer. Leukocytes obtained from female donors appear to be more sensitive to the in vitro immunotoxic effects of PFCs when their responses are compared to the results obtained using leukocytes from male donors. Mechanistic investigations demonstrated that inhibition of TNF-α release in THP-1 cells occurred at the transcriptional level. All PFCs, including PFOA and PFOS, decreased LPS-induced NF-κB activation. With the exception of PFOA, none of the PFCs tested was able to activate PPARα driven transcription in transiently transfected THP-1 cells, excluding a role for PPARα in the immunomodulation observed. PFBS and PFDA prevented LPS-induced I-κB degradation. Overall, these studies suggest that PFCs affect NF-κB activation, which directly suppresses cytokine secretion by immune cells. Our results indicate that PFOA is the least active of the PFCs examined followed by PFBS, PFDA, PFOS, PFOSA and fluorotelomer.

Potential anticancer effect of sodium caprate on human gastric cancer cells.

The role of sodium caprate (C10) in enhancing drug absorption is well established; however, little information is available on its role as an anticancer drug. This study aimed to evaluate the anticancer effect of C10 in gastric cancer cells. The mechanism of cytotoxicity of C10 was evaluated by western blotting following treatment of the gastric cancer cells with various concentrations of C10. C10 cytotoxicity was measured via MTS (3-(4, 5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H tetrazolium), lactate dehydrogenase (LDH), cAMP, and ATP assays. Gastric cancer cells were observed by electron microscopy following treatment with C10. Then, xenograft mice that were inoculated with gastric cancer cells were treated with C10 for 4 weeks, after which the changes in tumor size were measured. C10 triggered apoptosis in the gastric cancer cells through the mitochondrial pathway at concentrations of more than 0.2 mM. However, 15 mM of C10 induced necrosis in gastric cancer cells by causing cellular swelling and the formation of holes in the cell membrane. Levels of cAMP and ATP decreased significantly following exposure to 15 mM C10 for 1 h. Additionally, the size of the xenograft tumors was significantly reduced by 24% after 4 weeks of C10 treatment (p < 0.05). This study indicates that C10 induces apoptosis and necrosis in a concentration-dependent manner and has clear anticancer effects on gastric cancer cells.