Paving the way for application of next generation risk assessment to safety decision-making for cosmetic ingredients.

Next generation risk assessment (NGRA) is an exposure-led, hypothesis-driven approach that has the potential to support animal-free safety decision-making. However, significant effort is needed to develop and test the in vitro and in silico (computational) approaches that underpin NGRA to enable confident application in a regulatory context. A workshop was held in Montreal in 2019 to discuss where effort needs to be focussed and to agree on the steps needed to ensure safety decisions made on cosmetic ingredients are robust and protective. Workshop participants explored whether NGRA for cosmetic ingredients can be protective of human health, and reviewed examples of NGRA for cosmetic ingredients. From the limited examples available, it is clear that NGRA is still in its infancy, and further case studies are needed to determine whether safety decisions are sufficiently protective and not overly conservative. Seven areas were identified to help progress application of NGRA, including further investments in case studies that elaborate on scenarios frequently encountered by industry and regulators, including those where a 'high risk' conclusion would be expected. These will provide confidence that the tools and approaches can reliably discern differing levels of risk. Furthermore, frameworks to guide performance and reporting should be developed.

Ultrahigh-vacuum organic molecular-beam deposition system for in situ growth and characterization.

A compact ultrahigh-vacuum molecular-beam deposition system has been developed for the in situ synthesis of organic thin films and multilayers. The system incorporates all the features (heater, thickness monitor, evaporators) necessary for controlled organic thin-film growth. It can be used independently, or it can be docked to the in situ growth system and transferred to other instruments of the PGM beamline, thus allowing extensive film preparation and characterization. A manipulator dedicated to specimen preparation and organic-film deposition with temperature control between 200 K and ∼800 K has been developed. The design and performance of the system are reported with emphasis on a novel solution of masks developed to achieve position-dependent film deposition. To demonstrate the enhanced capabilities of the PGM beamline in the growth and in the characterization of electronic-structure studies of organic molecular films and their heterostructures through synchrotron-based spectroscopies, this paper presents some preliminary results of a study of Fe-phthalocyanine growth on Si substrates and on in situ prepared La0.67Sr0.33MnO3 buffer layers on SrTiO3 single crystal.

Elastin structure and its involvement in skin photoageing.

Skin aging is a complex process that may be caused by factors that are intrinsic and extrinsic to the body. Ultraviolet (UV) radiation represents one of the main sources of skin damage over the years and characterizes a process known as photoaging. Among the changes that affect cutaneous tissue with age, the loss of elastic properties caused by changes in elastin production, increased degradation and/or processing produces a substantial impact on tissue esthetics and health. The occurrence of solar elastosis is one of the main markers of cutaneous photoaging and is characterized by disorganized and non-functional deposition of elastic fibers. The occurrence of UV radiation-induced alternative splicing of the elastin gene, which leads to inadequate synthesis of the proteins required for the correct assembly of elastic fibers, is a potential explanation for this phenomenon. Innovative studies have been fundamental for the elucidation of rarely explored photoaging mechanisms and have enabled the identification of effective therapeutic alternatives such as cosmetic products. This review addresses cutaneous photoaging and the changes that affect elastin in this process.

Comparison between fibroblasts and mesenchymal stem cells derived from dermal and adipose tissue.

OBJECTIVE: Stem cells have the ability to renew themselves and differentiate into various cell types. For this reason, numerous research groups have been studying these cells for their therapeutic potential. Some of the therapies, however, are not producing the expected results because of contamination by other cell types, especially by fibroblasts. In the cosmetic industry, stem cells are used to test the efficacy of anti-ageing and rejuvenation products. The purpose of this work was to gain a better understanding of the differences in phenotype, in gene expression associated with stem cells, in the pattern of cell surface proteins and in the differentiation capacity of adipose-derived stem cells, of skin-derived stem cells and of commercially available fibroblasts. METHODS: In this study, we compared fibroblasts with mesenchymal stem cells derived from bone marrow, skin (dermis) and adipose tissue, to assess the differentiation potential of fibroblasts. Dermal and adipose stem cells were isolated from aesthetic surgery patients, and fibroblasts were obtained from a commercial source. The following parameters were used in this study: immunophenotypic profile (positive: CD29, CD73, CD90 and CD105; negative: CD14, CD45 and HLA-DR); differentiation into osteoblastic, chondrogenic and adipogenic cell types; and PCR array to analyse the gene expression of cells isolated from different culture passages. RESULTS: Fibroblasts express the same cell immunophenotypic markers, as well as the genes that are known to be expressed in stem cells, and were shown to be expressed also in adipose and dermis stem cells. Fibroblasts are also able to differentiate into the three cell lineages mentioned above, that is, adipocytes, osteocytes and chondrocytes. CONCLUSION: Human dermal fibroblasts have a potential to adhere to plastic surfaces and differentiate into other cell types. However, for stem cells intended to be used in cosmetics, experiments conducted with contaminated fibroblasts may produce poor or even falsely negative results for the efficacy of the active ingredient or formulation and thus conceal their promising effects as anti-ageing and skin rejuvenation products.

In vitro induction of apoptosis, necrosis and genotoxicity by cosmetic preservatives: application of flow cytometry as a complementary analysis by NRU.

Preservatives are used in cosmetics to prevent microbial contamination; however, some preservatives are not free of allergenic and cytotoxic potential. Allergenicity and cytotoxicity potential values are major aspects of preservative safety, which determine limitations and maximum concentration dose in a cosmetic product. The purpose of this study was to investigate and compare the in vitro apoptosis, necrosis and genotoxicity-inducing potential of five different types of preservatives: Phenoxyethanol (PE), Propylparaben (PP), Methylparaben (MP), Benzyl Alcohol (BA) and Ethylhexyl Glycerine (EG). In vitro experiments were carried out on human dermal fibroblasts by a quantitative flow cytometry method, using specific cell markers (Annexin V, Propidium Iodide and H2AX). We compared the resulting cell viability by means of neutral red uptake (NRU) and established the IC(50) . Our results showed that PE, PP, MP and BA have similar cytotoxic mechanisms (high apoptosis and necrosis levels only at the test concentration of 1%), whereas EG showed only an apoptosis pathway. For genotoxicity, both parabens yielded the highest values. Results obtained by flow cytometry for necrosis were comparable to those produced by NRU; however, NRU does not distinguish apoptosis from necrosis. We propose that flow cytometry is a more sophisticated methodology for understanding the cytotoxic mechanisms of cosmetic preservatives and can be used to complement the NRU.

A new paradigm in the periodontal disease progression: gingival connective tissue remodeling with simultaneous collagen degradation and fibers thickening.

Bacterial dental plaque is considered to be the main cause of periodontal diseases, but progression of the disease is also related to the host inflammatory response. The earliest affected tissue is the gingiva, but the specific mechanisms involved in the onset of this condition remain unclear. Frequently, collagen degradation is pointed as the main marker of periodontal disease progression, but the organization of the fibers in the gingival tissue is still unknown. The aim of the present study was to investigate the gingival extracellular matrix in a model of ligature-induced periodontal disease. Analysis of the microbiota indicated a progressive increase in the ratio of Gram-negative/Gram-positive microorganisms. There was no difference in the organization of reticulin fibers next to the epithelial basement membrane, whereas the arrangement of collagen fibers in the gingival connective tissue was significantly affected. Animals with inflammation presented a reduction of 35% in the total area occupied by collagen fibers. However, these fibers were thicker and more densely packed. These alterations involve type I, type III and type VI collagens as determined by immunohistochemistry. The results demonstrated the occurrence of marked reorganization of the gingival extracellular matrix in response to the inflammatory process, indicating a new paradigm in the periodontal disease progression: collagen degradation and fibers thickening, simultaneously.

The influence of type I diabetes mellitus on the expression and activity of gelatinases (matrix metalloproteinases-2 and -9) in induced periodontal disease.

BACKGROUND AND OBJECTIVE: Periodontal disease corresponds to a group of lesions that affect the tooth-supporting tissues present in the dental follicle. Although bacterial plaque is important, the immune response also contributes to the destruction of periodontal tissues. Diabetes mellitus is closely associated with the development, progression and severity of periodontal disease because it not only affects extracellular matrix organization but also the tissue response to inflammation. The objective of the present investigation was to study the influence of diabetes on experimental periodontal disease by evaluating the degradation of extracellular matrix through the analysis of matrix metalloproteinase (MMP)-2 and MMP-9 expression and activity, using immunofluorescence, zymography and real-time reverse transcription-polymerase chain reaction. MATERIAL AND METHODS: Wistar rats were divided into normal and diabetic groups and evaluated 0, 15 and 30 d after the induction of periodontal disease by ligature. RESULTS: MMP-2 and -9 were detected in epithelial cells, in the blood vessel endothelium and in connective tissue cells. The same profile of enzymatic expression of MMP-2 and -9 was observed in normal and diabetic animals, with a peak in activity at day 15 of inflammation. However, in diabetic animals, MMP-2 gelatinolytic activity was reduced after the inflammatory stimulus, whereas that of MMP-9 was increased. MMP-2 gene expression decreased with inflammation in both normal groups and groups with diabetes. In contrast, MMP-9 expression increased in normal animals and decreased in diabetic animals after inflammation. CONCLUSION: The results suggest the involvement of MMP-2 and -9 in the dynamics of periodontal disease and that variation in their expression levels results in differences in tissue organization and wound healing in normal and diabetic animals.

The influence of type I diabetes mellitus in periodontal disease induced changes of the gingival epithelium and connective tissue.

Periodontal disease constitutes the most frequent chronic diseases in human dentition. Bacterial plaque is the main etiologic agent, although it is the host immune response that causes periodontal tissue destruction. Diabetes is considered an important risk factor, not only for the onset but also for progression of the disease. The aim of this study was to analyze structural changes in the rat gingival epithelium and connective tissue in response to the experimental periodontal disease induced by the ligature technique, under the influence of diabetes. The results showed that experimental periodontal disease is characterized by marked inflammation, affecting both the epithelial and connective tissues, causing degeneration of the dermal papilla, increase in the number of inflammatory cells, destruction of reticulin fibers, and accumulation of dense collagen fibers (fibrosis). These changes were worsened by diabetes, apparently by hampering the inflammatory response and affecting tissue repair of the affected tissues.

Parameters for assessing the aquatic environmental impact of cosmetic products.

The cosmetic industry's growing concern about the impact of its supply chain on the environment, sustainability of raw materials, and biodiversity increases the need to ensure that the final product has a lower environmental impact. The objective of this review is to summarize and compare the information available from international organizations and legislation regarding the main criteria used to assess raw materials for aquatic toxicity, as well as the most suitable alternative methods for obtaining assessment parameters. Using the literature available in databases, a review of the scientific literature and international legislation, this work discusses and compares the parameters established by international organizations such as the Environmental Protection Agency (EPA) and Cradle to Cradle (C2C), as well as European legislation, namely, European Regulation 1272/2008, for assessing environmental impact. Defining the ecotoxicity parameters of the main classes of raw materials in rinse-off cosmetic products can enable the development of products that are more environmentally sustainable, prioritizing substances with less environmental impact.