ABSTRACT
This study describes the within- and between-laboratory reproducibility (WLR and BLR) of a Time-to-Toxicity (TTT) approach for chemicals based on the SkinEthic™ HCE tissue construct, capable to distinguish chemicals that do not require classification for serious eye damage/eye irritation (No Cat.) from chemicals that require classification for eye irritation (Cat. 2), and serious eye damage (Cat. 1). The WLR and BLR was assessed with three participating laboratories. Each laboratory tested 40 coded chemicals in three independent runs. The predictive capacity of the method was assessed on a larger set of 150 chemicals (70 liquids and 80 solids) by combining the results of this study with the results of the test method developer. The WLR for the 20 liquids ranged from 85% to 95% with a BLR of 90%. For the 20 solids, a WLR and BLR of 100% was obtained. The test method developer obtained a WLR of 80% and 95%, based on 50 liquids and 48 solids tested in three independent runs, respectively. Regarding the predictive capacity, the SkinEthic™ HCE TTT test method identified 80.8% Cat. 1, 69.2% Cat. 2, and 74.9% No Cat. correctly. An independent peer review panel concluded that based on all available data, the relevance and reliability of the SkinEthic™ HCE TTT has been demonstrated for discriminating the three UN GHS eye hazard categories.
Subject(s)
Epithelium, Corneal/drug effects , Irritants/classification , Irritants/toxicity , Toxicity Tests/methods , Animal Testing Alternatives , Humans , Laboratories , Reproducibility of Results , United NationsABSTRACT
The aim of this screening study was to evaluate the efficacy of different proprietary mixtures of amino acid and hyaluronic acid (HA) in stimulating the production of extracellular matrix (ECM) components, particularly the neo-synthesis of elastin, and in promoting a more efficient deposition of elastic fibres (elastogenesis), while at the same time maintaining the stimulation of collagen. The study has allowed identification of the optimal ratios between the amino acids (AA) for the production of collagen and elastin. Human primary dermal fibroblasts from a 44-year-old female donor were used as a test system in an experimental design based on the evaluation of the expression of relevant ECM genes using a transcriptomic dynamic approach. The expression of ECM genes was evaluated by RTqPCR from 24 to 120 hours in the presence of the test items. Moreover, the production of ECM proteins was verified by Western blot analysis after a 120 h treatment period. In addition to elastin, collagen IV, a fundamental structural component of the basal lamina responsible for epithelial and connective tissue anchoring, was analysed as potential target for the modulation of ECM protein production by human fibroblast. The first phase of the study demonstrated that alanine and valine are essential to promote production of elastin, of which they are important constituents. The second phase of the study, which was conducted to clarify the interactions between the different clusters of AA, demonstrated that it is necessary to choose a mixture that contains specific amounts of amino acids of both proteins, collagen and elastin, to give a significant response and a significant production of both. This also proves the existence of a ratio between the 2 clusters (AA elastin/AA collagen) that guarantees an adequate and balanced response to gene expression and production by fibroblasts, collagen and elastin. The study has allowed identification of the optimal ratios between the AA for the production of collagen and elastin.
Subject(s)
Amino Acids/pharmacology , Extracellular Matrix Proteins/biosynthesis , Extracellular Matrix/metabolism , Fibroblasts/metabolism , Hyaluronic Acid/pharmacology , Adult , Cells, Cultured , Female , HumansABSTRACT
A new drug, pirifibrate, was investigated in a multicenter study of 100 patients with type IIa, IIb, or IV hyperlipoproteinemia (HLP). After one month of dieting, patients completed six months of treatment with a dose of 1,500 mg/day of pirifibrate. An average fall of about 20% in plasma cholesterol was observed in type IIa and IIb HLP, and more than 50% in the triglycerides in type IIb and IV HLP. Both reductions were statistically significant (P less than 0.00005). Increases in the alpha-lipoproteins were observed in the three types of HLP. The pre-beta-lipoproteins showed a statistically significant fall in type IIb and IV HLP. Variations observed in beta-lipoproteins were significant only in some controls with type IV, HLP, who had low basal levels.
