Search

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. published

Novel 4,5,6,7-tetrahydropyrazolo[1,5

The need for effective and safe therapies for cancer is growing as aging is modifying its epidemiology. Cold atmospheric plasma (CAP) has gained attention as a potential anti-tumor therapy. CAP is a gas with enough energy to ionize a significant fraction of its constituent particles, forming equal numbers of positive ions and electrons. Timely-resolved output voltage measurement, emission spectroscopy, and quantification of reactive species (RS) in plasma-activated media (PAM) were performed to characterize the physical and chemical properties of plasma. To assess the cytotoxicity of cold atmospheric plasma in human tumors, different cell lines were cultured, plated, and exposed to CAP, followed by MTT and SRB colorimetric assays 24 h later. Human fibroblasts, phenotypically normal cells, were processed similarly. Plasma cytotoxicity was higher in cells of breast cancer, urinary bladder cancer, osteosarcoma, lung cancer, melanoma, and endometrial cancer. Cytotoxicity was time-dependent and possibly related to the increased production of hydrogen peroxide in the exposed medium. Sixty seconds of CAP exposure renders selective effects, preserving the viability of fibroblast cells. These results point to the importance of conducting further studies of the therapy with plasma.

Investigation of novel 4,5,6,7-tetrahydropyrazolo[1,5-a]pyridine-fused chlorins, derived from 5,10,15,20-tetrakis(pentafluorophenyl)porphyrin, as PDT agents against melanoma and esophagus cancer is disclosed. Diol and diester fluorinated ring-fused chlorins, including derivatives with 2-(2-hydroxyethoxy)ethanamino groups at the phenyl rings, were obtained via a two-step methodology, combining S(N)Ar and [8π + 2π] cycloaddition reactions. The short-chain PEG groups at the para-position of the phenyl rings together with the diol moiety at the fused pyrazole ring promote a red-shift of the Soret band, a decrease of the fluorescence quantum yield and an increase of the singlet oxygen formation quantum yield, improving the photophysical characteristics required to act as a photosensitizer. Introduction of these hydrophilic groups also improves the incorporation of the sensitizers by the cells reaching cellular uptake values of nearly 50% of the initial dose. The rational design led to a photosensitizer with impressive IC(50) values, 13 and 27 nM against human melanoma and esophageal carcinoma cell lines, respectively.

Experimental evidence highlights nuclear factor (erythroid-derived 2)-like 2 (Nrf2) as a molecular target in Alzheimer&rsquo, s disease (AD). The well-known effect of electrophilic cysteine-reactive skin allergens on Nrf2-activation led to the hypothesis that these compounds could have a therapeutic role in AD. This was further supported by the neuroprotective activity of the skin allergen dimethyl fumarate (DMF), demonstrated in in vivo models of neurodegenerative diseases. We evaluated the effect of the cysteine-reactive allergens 1,4-phenylenediamine (PPD) and methyl heptine carbonate (MHC) on (1) neuronal redox imbalance and calcium dyshomeostasis using N2a wild-type (N2a-wt) and human APP-overexpressing neuronal cells (wild-type, N2a-APPwt) and (2) on neuroinflammation, using microglia BV-2 cells exposed to LPS (lipopolysaccharide). Phthalic anhydride (PA, mainly lysine-reactive), was used as a negative control. DMF, PPD and MHC increased Hmox1 gene and HMOX1 protein levels in N2a-APPwt cells suggesting Nrf2-dependent antioxidant activity. MHC, but also PA, rescued N2a-APPwt mitochondrial membrane potential and calcium levels in a Nrf2-independent pathway. All the chemicals showed anti-inflammatory activity by decreasing iNOS protein in microglia. This work highlights the potential neuroprotective and anti-inflammatory role of the selected skin allergens in in vitro models of AD, and supports further studies envisaging the validation of the results using in vivo AD models.

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.

Background Osteosarcoma, a malignant tumor characterized by bone or osteoid formation, is the second most common primary bone neoplasm. Clinical symptoms include local and surrounding pain, unrelieved by rest or anesthesia. Osteosarcoma has a poor chemotherapeutic response with prognosis dependent on complete tumor excision. Therefore, for inoperable osteosarcoma new therapeutic strategies are needed. The present study aimed to develop murine models of cranial and vertebral osteosarcoma that facilitate simple clinical monitoring and real-time imaging to evaluate the outcome of photodynamic therapy based on a previously developed photosensitizer. Methods Balb/c nude mice were divided into two groups: the cranial and vertebral osteosarcoma groups. Each group was further subdivided into the photodynamic therapy-treated and untreated groups. Images were obtained by scintigraphy with 99mTc-MIBI and radiography. Tumor growth, necrotic area, osteoid matrix area, and inflammatory infiltration were analyzed. Results Cranial and vertebral tumors could be macroscopically observed and measured. Radiographic and scintigraphic images showed tumor cells present at the inoculation sites. After photodynamic therapy, scintigraphy showed lower tumoral radiopharmaceutical uptake, which correlated histologically with increased necrosis. Osteoid matrix volume increased, and tumor size decreased in all photodynamic therapy-treated animals. Conclusion Cranial and vertebral osteosarcoma models in athymic mice are feasible and facilitate in vivo monitoring for the development of new therapies. Photodynamic therapy is a potential antitumoral treatment for surgically inoperable osteosarcoma.

As the body's first line of defense, the skin is the organ most frequently exposed to chemicals present in personal hygiene products, household products, or materials used in the work environment. In this context, skin disorders account for more than 40 % of all occupational and work-related diseases, constituting a significant public health burden. Among skin disorders, allergic contact dermatitis (ACD) is the most prevalent occupational disease and the most common form of immunotoxicity in humans. ACD is a T-cell-mediated skin inflammation resulting from the priming and expansion of allergen-specific CD4+ and CD8+ T cells. The clinical condition is characterized by local skin rash, itchiness, redness, swelling, and lesions, being mainly diagnosed by the patch test. Upon ACD diagnosis, avoiding the exposure to the triggering allergen is the mainstay of treatment to prevent future flares. In cases where avoidance is not possible, the use of a standard of care interim treatments such as steroid creams or ointments, barrier creams, and moisturizers are strongly recommended to alleviate symptoms. In this review, we sought to provide the reader with an overview of the pathophysiology of ACD as well as the currently available pharmacological treatment options. Furthermore, a comprehensive outline of several preventive strategies is also provided.

The discovery of Pt-chlorin-type theranostic agents is described. Luminescent Pt(II) 4,5,6,7-tetrahydropyrazolo[1,5-a]pyridine-fused chlorins, with different degrees of hydrophilicity, have been synthesized and their in vitro photocytotoxicity against human melanoma, oesophageal and bladder carcinomas was studied. A di(hydroxymethyl)-substituted chlorin was identified as a privileged molecule to explore imaging-guided photodynamic therapy. In addition to the high activity as PDT agent and absence of cytotoxicity per se, this molecule showed the ideal photophysical and photochemical properties. In vivo studies using a A375 melanoma mouse model, proved the extraordinary properties of this chlorin as a luminescent probe and the ability to impair tumor growth, making image guided treatment and follow up a possibility.

Introduction We recently developed a new type of photochemically stable platinum (II) chlorins, which are remarkable photosensitizers that can be used in photodynamic therapy (PDT), due to its therapeutic capacity. Simultaneously, due to its highly luminescence proprieties, in the biological relevant 650–850 nm red and near infrared spectral region, they may be used for biological imaging. In addition, photophysical studies indicate that they may be used as ratiometric oxygen sensors. Material and methods Compounds with different degrees of hydrophilicity were synthesised and characterised. Photocytotoxicity studies were carried out against two human tumour cell lines, the OE19 line of oesophageal carcinoma and the A375 line of melanocytic melanoma. The formulation of the sensitizers consisted in a 1 mg/mL solution in DMSO and the desired concentrations being achieved by successive dilutions. The sensitizers were administered in several concentrations (from 50 nM to 10 µM) and, 24 hour after incubation, cells were washed with PBS and new drug-free medium was added. Plates were irradiated ( Results and discussions Preliminary cytotoxicity studies indicate that, in both cell lines, platinum (II) chlorins with more hydrophilic features require lower doses of photosensitizer to induce a significant photocytotoxic effect on tumour cells. Our best results were IC50 value of 165.9 nM (confidence interval at 95%: [77.9; 356.6]) for A375 line and 498.6 nM (confidence interval at 95%: [283.5; 876.5]) for OE19 line. However, and given that the confidence intervals were too large, it was hypothesised that this type of compounds would be aggregating in the biological medium. This hypothesis was corroborated by additional photophysical studies. As such, disaggregation was performed with the use of a non-ionic surfactant since surface active agents (surfactants) has been widely used for enhancing solubilisation of poorly soluble drugs. Conclusion Although photocytotoxicity studies reveal that the platinum (II) chlorins tested would be very promising for PDT, further cytotoxicity studies will be carried out using a novel formulation. This work was funded by Fundacao para a Ciencia e a Tecnologia (FCT): POCI-01–0145-FEDER-PTDC/QEQ-MED/0262/2014;COMPETE 2020 POCI-01–0145-FEDER-007630 and POCI-01–0145-FEDER-007440.

Introduction Photodynamic therapy (PDT) is a clinically approved therapeutic procedure, which is entering the mainstream of cancer treatments. Nowadays PDT has been successfully used in the treatment of skin cancers, but the use of PDT against melanoma can be compromised due to the natural resistance mechanism of some melanoma cancer cells. Thus, the search for new photosensitizers is a relevant research goal. Bladder cancer is also an interesting target to PDT, due to easy irradiation accessibility by cystoscopy. Material and methods A375 human melanoma cells and HT1376 human bladder cancer cells were plated. The formulation of the sensitizers consisted in a 1 mg/mL solution in DMSO and the desired concentrations being achieved by successive dilutions. The sensitizers were administered in several concentrations (from 1 nM to 10 mM) and cells were incubated for 24 hour. Controls were performed on every test. Cells were washed with PBS and new drug-free medium was added. Each plate was irradiated with a fluence rate of 7.5 mW/cm2, to reach 10 J. Evaluation by MTT assay was performed 24 hour after the photodynamic treatment in order to evaluate the cytotoxic effect. Results and discussions Our previous in vitro PDT studies demonstrated that the increase of chlorins’ hydrophilicity of leads to higher activity against A375 melanoma cells. Therefore, a series of novel 4,5,6,7-tetrahydropyrazolo[1,5-a]pyridine-fused chlorins bearing dicarboxylic acid and monocarboxyic moieties were developed showing an interesting biological activity against the A375 and HT1376 cancer cells. Inhibition of the metabolic activity seems to be dependent on the concentration of the sensitizers used. With the experimental metabolic activity values, it was possible to calculate the concentration of the sensitizers that inhibits the proliferation of cultures in 50% (IC50). For this series of compounds, IC50 values ranged from mM to nM concentrations. Nevertheless, a new molecule with an IC50 value of 67,93 nM stood out. Conclusion The compounds tested were active against human melanocytic melanoma A375 cells and human bladder HT1376 cancer cells. MTT assay showed that the metabolic activity was inversely proportional to the concentration of the photosensitizer. Interestingly low IC50 values in the nanomolar range encourage further studies. Funding The Foundation for Science and Technology: POCI-01–0145-FEDER-PTDC/QEQ-MED/0262/2014; (COMPETE 2020). POCI-01–0145-FEDER-007630 and POCI-01–0145-FEDER-007440.

Introduction Considering the increased need for alternatives to current treatments, a new therapy based on plasma, the fourth state of matter, has recently raised the medical community’s attention. The aim of this work was to evaluate the effect, selectivity and mechanisms of action of cold atmospheric plasma (CAP) in a human retinoblastoma cell line. Material and methods An electronic device was designed to generate CAP, in open air above multiwell plates where Y79 cell cultures were seeded. Plasma emission spectrum was captured by a spectrometer. In order to evaluate the cytotoxicity and selectivity of CAP, metabolic activity of similarly treated Y79 and human fibroblasts HFF1 cells was measured. Apoptosis detection, analysis of mitochondrial membrane potential (MMP) and cell morphology were studied to determine the type of cell death. Propidium-iodide/RNAse staining was used to study the cell cycle and genotoxic effects were assessed by comet assay. Oxygen and nitrogen reactive species (RS) and oxidative defenses were measured. In order to explore the interaction of the electric field with voltage-gated calcium channels, blockade with verapamil was applied. Clonogenic assay screened for long term survival. Results and discussions After 60 s of CAP treatment, the metabolic activity of Y79 cells decreased more than 50%, mostly due to apoptosis, while HFF1 endured viable. Cell survival was shortened. Accumulation of Y79 cells in S and G2/M phases was recorded, nevertheless, no DNA strand breaks were detected. Plasma emission spectrum displayed several peaks in ultraviolet domain. Concerning RS, the concentration of intracellular peroxides and nitric oxide was increased. However, antioxidative defenses were not triggered and reactive oxygen species inhibitors were not capable of abrogating cytotoxic effects of CAP. Similarly, verapamil did not protect cells from death. Conclusion This study suggests a potential novel therapy based on plasma able to selectively target tumour cells while preserving the non-inflammatory environment. Funding FCT, Portugal (UID/NEU/04539/2013), FEDER-COMPETE (FCOMP-01–0124-FEDER-028417, POCI-01–0145-FEDER-007440)

Retinoblastoma is a tumor that mainly affects children under 5 years, all over the world. The origin of these tumors is related with mutations in the RB1 gene, which may result from genetic alterations in cells of the germ line or in retinal somatic cells. In developing countries, the number of retinoblastoma-related deaths is higher due to less access to treatment, unlike what happens in developed countries where survival rates are higher. However, treatments such as chemotherapy and radiotherapy, although quite effective in treating this type of cancer, do not avoid high indices of mortality due to secondary malignances which are quite frequent in these patients. Additionally, treatments such as cryotherapy, thermotherapy, thermochemotherapy, or brachytherapy represent other options for retinoblastoma. When all these approaches fail, enucleation is the last option. Photodynamic therapy might be considered as an alternative, particularly because of its non-mutagenic character. Photodynamic therapy is a treatment modality based on the administration of photosensitizing molecules that only upon irradiation of the tumor with a light source of appropriate wavelength are activated, triggering its antitumor action. This activity may be not only due to direct damage to tumor cells but also due to damage caused to the blood vessels responsible for the vascular supply of the tumor. Over the past decades, several in vitro and in vivo studies were conducted to assess the effectiveness of photodynamic therapy in the treatment of retinoblastoma, and very promising results were achieved.