The preparation of a reconstructed human epidermis is described with examples of its utilization in in vitro studies. The model was obtained by culturing normal human keratinocytes at high cell density for 14 days in serum-free and high calcium (1.5 m M) medium on an inert polycarbonate filter at the air-liquid interface. These stratified cultures showed histological features similar to those observed in vivo in the epidermis: a proliferating basal layer and differentiating spinous, granular, and cornified layers. Electron microscopy illustrated lamellar bodies, junctions and keratohyalin granules. Immunofluorescent localization of epidermal markers (keratins 14 and 10, involucrin and filaggrin) revealed typical differentiation. This in vitro reconstructed tissue was used in studies of toxic effects of chemicals. The modelled tissue showed progressive cytotoxicity of a skin irritant (benzalkonium chloride) and a sensitizer (dinitrochlorobenzene) as assessed by MTT assay. Moreover, differential release of interleukin-1alpha and interleukin-8 were measured after 20 h of incubation allowing the irritant to be distinguished from the sensitizer. Permeation studies indicated efficient barrier function of the reconstructed epidermis, as well as metabolizing properties towards hormones. This model can be custom-made and is potentially useful for studies involving keratinocytes in the epidermis, in basic science, dermatology or toxicology.

Inorganic arsenic trioxide (As 2 O 3 ) is a highly effective treatment for acute promyelocytic leukemia (APL). However, other cancers do not respond well to this form of arsenic at clinically achievable doses. We tested a novel arsenical, S-dimethylarsino-glutathione (darinaparsin) for efficacy in various malignancies in vitro. Darinaparsin is significantly more potent than As 2 O 3 at mediating apoptosis in various malignant cell lines and is highly active against APL cells derived for As 2 O 3 resistance. We provide evidence that darinaparsin triggers apoptosis by inducing signaling pathways that do not completely overlap with As 2 O 3 . We show that darinaparsin induces apoptosis and oxidative stress to a greater extent than As 2 O 3 , although like As 2 O 3 , darinaparsin-induced toxicity is c-Jun NH 2 -terminal kinase-dependent. However, darinaparsin does not induce promyelocytic leukemia/retinoic acid receptor a (PML/ RARa) degradation or rearrange PML nuclear bodies in APL cells, nor is its toxicity increased by glutathione depletion. Darinaparsin treatment results in higher intracellular arsenic accumulation when compared to As 2 O 3 treatment. This may be explained by our finding that As 2 O 3 , but not darinaparsin, is efficiently exported by ABCC1, suggesting increased therapeutic efficacy of darinaparsin in ABCC1-overexpressing tumors. Our studies indicate that darinaparsin efficiently kills tumor cells with increased antioxidant capacity and drug exporters and suggest that darinaparsin may have a broader therapeutic spectrum than As 2 O 3 .

The regulation of intestinal epithelial cell adhesion and migratory properties is often compromised in inflammatory bowel disease (IBD). Despite an increasing interest in bone morphogenetic protein (Bmp) signaling in gut pathologies, little is known of the specific roles played by individual Smads in intestinal epithelial functions. In the present study, we generated a mouse model with deletion of Smad5 transcriptional effector of the Bmp signaling pathway exclusively in the intestinal epithelium. Proliferation, migration, and apical junctional complex (AJC) protein expression were analyzed by immunofluorescence and Western blot. Human intestinal biopsies from control and IBD patients were analyzed for SMAD5 gene transcript expression by quantitative PCR (qPCR). Smad5(ΔIEC) and control mice were subjected to dextran sulfate sodium (DSS)-induced experimental colitis, and their clinical and histological symptoms were assessed. Loss of Smad5 led to intestinal epithelial hypermigration and deregulation of the expression of claudin-1 and claudin-2. E-cadherin was found to be equally expressed but displaced from the AJC to the cytoplasm in Smad5(ΔIEC) mice. Analysis of SMAD5 gene expression in human IBD patient samples revealed a significant downregulation of the gene transcript in Crohn's disease and ulcerative colitis samples. Smad5(ΔIEC) mice exposed to experimental DSS colitis were significantly more susceptible to the disease and had impaired wound healing during the recovery phase. Our results support that Smad5 is partly responsible for mediating Bmp signals in intestinal epithelial cells. In addition, deficiency in epithelial Smad5 leads to the deregulation of cell migration by disassembling the AJC with increasing susceptibility to experimental colitis and impairment in wound healing.

<b><i>Background:</i></b> Off-label drug use is associated with an increased risk of adverse drug reactions. It is common in pediatrics and in rare diseases, which are two characteristics applying to vascular anomalies (VA). <b><i>Objectives:</i></b> The aim of this work was to quantify off-label drug use in VA and assess its safety. <b><i>Methods:</i></b> A review was conducted to extract a list of drugs used in VA management. A drug was considered to have significant safety concerns if a black box warning was present or if a serious adverse drug reaction (SADR) was reported in at least 1% of the patients (SADR is defined as a noxious and unintended response to a drug that occurs at any dose and results in hospitalization, prolongation of existing hospitalization, congenital malformation, persistent or significant disability or incapacity, life-threatening condition, or death). The labelling status and safety of each drug was assessed based on the product monograph, Micromedex, and the FDA data. <b><i>Results:</i></b> We found that 98.9% of the inventoried drugs were used off-label or unlicensed for VA management. Only the oral solution of propranolol hydrochloride (Hemangeol®) for the treatment of infantile hemangiomas is approved. Significant safety issues concerned 73% of the drugs and were more frequent among systemic than locally delivered drugs. <b><i>Conclusions:</i></b> Off-label drug use in VA is the rule and not the exception. Significant safety concerns are common. It is necessary to carefully weigh risk and benefits for every patient when using systemic and local treatments carrying safety concerns. Patients should be openly informed and involved in the decision-making process.

Off-label drug prescribing, frequent in the treatment of vascular anomalies (VA), relies on the quality of the literature reporting drug efficacy and safety. Our objective is to review the level of evidence (LOE) surrounding drug use in VA, which is more prevalent in pediatric care. A list of drugs used in VA was created with a literature review in July 2020. For each drug listed, the article displaying the highest LOE was determined and then compared between efficacy/safety data, routes of administration, pharmacological categories and a subset of VA. The influence of research quality on study results was also explored. The median LOE for the 74 drugs identified poor methodological quality, with a predominance of retrospective studies or case reports. Drug safety is currently inadequately reported. This is alarming as many treatments display significant safety concerns. Also, current literature displays major publication bias that probably leads to overestimation of drug efficacy in VA.

Background A student psychological health survey, conducted in 2015-2016 among over 10,000 students at the University of Montreal (UdeM), gives an alarming picture of psychological distress associated to feelings of loneliness. The objective of this phenomenological study is to better understand the experience of isolation from the perspective of UdeM graduate students. Methods As part of a qualitative methods course, five semi-directed interviews and a focus group (n = 8) were conducted with graduate students and a psychologist from UdeM. Hybrid thematic analysis of verbatim and inter-rater debriefing were conducted using NVivo 11 software. Results Thematic analysis illustrates that most graduate students feel isolated at some point during their studies, but also that the impact and the meaning of this loneliness feeling is variable. It can be perceived positively when it is sought, temporary and/or allows one to be more productive. It can be perceived negatively when it is involuntary, constant over time and/or does not improve academic effectiveness. Personality, academic and social contexts, as well as support by peers and supervisors appear to modify feelings of isolation. Conclusions This study demonstrates the importance of context for graduate students' feelings of isolation. Further research is needed to move towards saturation of perspectives around this phenomenon. Key messages Graduate students reported that the experience and the repercussions of isolation may differ in whether it is sought or involuntary. Factors that seem to influence the feeling of loneliness include academic context and supervisor support. Further research is needed to discriminate the impact of these different contextual factors.

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Intestinal epithelial cells form a protective barrier in limiting gut luminal content potentially harmful to the host. Upon gut epithelium injury, several signals instruct epithelial cells to undergo a rapid healing process. Defects in this process induce inflammatory responses and can further evolve into chronic gut inflammatory diseases. We previously identified the transcription factor CUX1 as crucial for protecting against experimental colitis in mice. However, the precise molecular mechanisms by which CUX1 intervenes during this biological process are unknown. Our aim was to evaluate CUX1 biological and functional roles during intestinal epithelial cell wound healing. RNAi knockdown of CUX1 in intestinal epithelial cells revealed a crucial role for this regulator in migratory response following wounding assays. Gene expression profiling identified several gene transcripts modulated in absence of CUX1 during wound healing for which a significant number was associated with cell motility and cytoskeleton function. Chromatin immunoprecipitation assays identified the guanine nucleotide exchange factor Vav2 gene as a direct target for CUX1. Coincidently, reduction of VAV2 in absence of CUX1 was associated with a significant decrease of RAC1 activity in response to epithelial wounding. Our results identify a novel pathway by which CUX1 regulates normal intestinal epithelial cell restitution.