Evaluating Skin Sensitization Via Soft and Hard Multivariate Modeling.

Allergic contact dermatitis is the most frequent manifestation of immunotoxicity in humans with a prevalence rate of 15% to 20% over general population. Skin sensitization is a complex end point that was for a long time being evaluated using animal testing. Great efforts have been made to completely substitute the use of animals and replace them by integrating data from in vitro and in chemico assays with in silico calculated parameters. However, it remains undefined how to make the best use of the cumulative data in such a way that information gain is maximized and accomplished with the fewest number of tests possible. In this work, 3 skin sensitization prediction models were considered: one to discriminate sensitizers from non-sensitizers, considering a 2-level scale; one according to the GHS, considering a 3-level scale; and the other to categorize potency in a 6-level scale, according to available human data. We used a data set of known human skin allergens for which in vitro, in chemico, and in silico descriptors where available to build classifiers based on soft and hard multivariate modeling. Model building, optimization, and refinement resulted in 100% accuracy in distinguishing between sensitizers and non-sensitizers. The same model was able to perform the characterization, in 3 and 6 levels, respectively, with 98.8 and 97.5% accuracy. Combining data from in vitro and in chemico tests with in silico descriptors is relatively simple to implement and some predictors are fitting the adverse outcome pathway for skin sensitization.

Development of a new hydrogel for the prevention of allergic contact dermatitis.

Allergic contact dermatitis (ACD) is the most prevalent occupational disease and the most common form of immunotoxicity in humans. Preventing exposure to the triggering allergens is the mainstay of treatment. However, avoidance is not always possible in an occupational setting. From a pathophysiological point of view, a variety of events are involved in the development of ACD, including the formation of immunogenic complexes following the stable association of the allergen with skin proteins, which is thought to be the molecular initiating event responsible for the development of ACD. Previously, the team identified molecules that exhibited higher antiallergic potential due to their capacity to block the interaction between allergens and skin proteins. These assumptions were the starting point for the design of this work aiming to develop and characterize a new hydrogel containing the active ingredients lysine and N-acetyl cysteine under the premises of quality- and safety- by design. Two factorial plannings were established envisioning the optimization of the hydrogel in terms of mechanical and rheological properties. In vitro release and permeation studies supported its skin surface barrier effect. In addition, the selected hydrogel proved to be safe without causing human skin irritation or skin sensitization.

Exosomes as new therapeutic vectors for pancreatic cancer treatment.

Pancreatic cancer (PC) is one of the deadliest cancers with a very short rate of survival and commonly without symptoms in its early stage. This absence of symptoms can lead to a late diagnosis associated with an advanced metastasis process, for which therapy is not effective. Although with extensive research in this field, the 5-year survival rate has not increased significantly. Notwithstanding, novel insights on risk factors, genetic mutations and molecular mechanisms pave the way for novel therapeutics that urge with a significant part of PC patients presenting resistance to chemotherapy treatments. Exosomes are presented as a promising strategy, working as delivery systems, since they can transport and release their cargoes after fusing with the membrane of pancreatic cells. Exosomes present advantages over liposomes, being less toxic and reaching higher levels in the bloodstream, working as molecule carriers that can inhibit oncogenes, activating tumor suppressor genes and inducing immune responses as well as controlling cell growth. This review intends to provide an overview about the scientific and clinical studies regarding the entire process, from isolation and purification of exosomes, to their design and transformation into anti-oncogenic drug delivering systems, particularly to target PC cells.

Neurotensin decreases the proinflammatory status of human skin fibroblasts and increases epidermal growth factor expression.

Fibroblasts colonization into injured areas during wound healing (WH) is responsible for skin remodelling and is also involved in the modulation of inflammation, as fibroblasts are immunologically active. Herein, we aimed to determine neurotensin effect on the immunomodulatory profile of fibroblasts, both in homeostatic and inflammatory conditions. Neurotensin mediated responses occurred through NTR1 or NTR3 receptors, while under inflammatory conditions NTR1 expression increase seemed to modulate neurotensin responses. Among different immunomodulatory genes, CCL11, IL-8, and IL-6 were the most expressed genes, while CCL4 and EGF were the less expressed genes. After neurotensin exposure, IL-8 mRNA expression was increased while CCL11 was decreased, suggesting a proinflammatory upregulation and chemoattractant ability downregulation of fibroblasts. Under inflammatory conditions, gene expression was significantly increased. After neurotensin exposure, CCL4 and IL-6 mRNA expression were decreased while CCL11 was increased, suggesting again a decrease in the chemoattractant capacity of fibroblasts and in their proinflammatory status. Furthermore, the expression of EGF, a crucial growth factor for skin cells proliferation and WH, was increased in all conditions. Overall, neurotensin, released by nerve fibers or skin cells, may be involved in the decrease of the chemotaxis and the proinflammatory status in the proliferation and remodelling phases of WH.

Anti-inflammatory activity of Cymbopogon citratus leaves infusion via proteasome and nuclear factor-κB pathway inhibition: contribution of chlorogenic acid.

ETHNOPHARMACOLOGICAL RELEVANCE: Cymbopogon citratus (DC.) Stapf leaves infusion is used in traditional medicine for the treatment of inflammatory conditions, however little is known about their bioactive compounds. AIM OF THE STUDY: Investigate the compounds responsible for anti-inflammatory potential of Cymbopogon citratus (Cy) on cytokines production induced by lipopolysaccharide (LPS) in human and mouse macrophages, and the action mechanisms involved. MATERIALS AND METHODS: An essential oil-free infusion of Cy was prepared and polyphenol-rich fractions (PFs) were obtained from it by column chromatography. Chlorogenic acid (CGA) was identified, by HPLC/PDA/ESI-MS(n). The expression of cytokines, namely TNF-α and CCL5, was analyzed by real-time RT-PCR, on LPS-stimulated human macrophages. Activation of nuclear factor (NF)-κB, a master regulator of inflammation, was investigated by western blot and gene reporter assay. Proteasome activity was assessed using a fluorogenic peptide. RESULTS: Cymbopogon citratus extract and its polyphenols inhibited the cytokine production on human macrophages. This supports the anti-inflammatory activity of Cy polyphenols in physiologically relevant cells. Concerning the effect on the activation of NF-κB pathway, the results pointed to an inhibition of LPS-induced NF-κB activation by Cy and PFs. CGA was identified, by HPLC/PDA/ESI-MS(n), as the main phenolic acid of the Cy infusion, and it demonstrated to be, at least in part, responsible by that effect. Additionally, it was verified for the first time that Cy and PFs inhibited the proteasome activity, a complex that controls NF-κB activation, having CGA a strong contribution. CONCLUSIONS: The results evidenced, for the first time, the anti-inflammatory properties of Cymbopogon citratus through proteasome inhibition and, consequently NF-κB pathway and cytokine expression. Additionally, Cy polyphenols, in particular chlorogenic acid, were highlighted as bioactive compounds.