Publications by authors named "Uwe Marx"

Article Synopsis
  • Researchers developed an intestinal-liver microphysiological system (MPS) to improve drug safety evaluations, intending to reduce reliance on animal models.
  • They used specific cell lines to create a "liver-on-chip" and tracked the effects of an acetaminophen (APAP) overdose on liver function over a short-term culture period of four days.
  • The study found significant indicators of liver injury, such as increased liver enzymes and reactive oxygen species, which suggest that this organ-on-chip model could effectively simulate toxic responses for drug testing.
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Current research on metabolic disorders and diabetes relies on animal models because multi-organ diseases cannot be well studied with standard in vitro assays. Here, we have connected cell models of key metabolic organs, the pancreas and liver, on a microfluidic chip to enable diabetes research in a human-based in vitro system. Aided by mechanistic mathematical modeling, we demonstrate that hyperglycemia and high cortisone concentration induce glucose dysregulation in the pancreas-liver microphysiological system (MPS), mimicking a diabetic phenotype seen in patients with glucocorticoid-induced diabetes.

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The HUMMIC skin-liver Chip2 microphysiological system using EpiDerm™ and HepaRG and stellate liver spheroids was used to evaluate the route-specific metabolism and toxicodynamic effects of genistein. Human-relevant exposure levels were compared: 60 nM representing the plasma concentration expected after topical application of a cosmetic product and 1 μM representing measured plasma concentrations after ingesting soya products. Genistein was applied as single and repeated topical and/or systemic doses.

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The HUMIMIC skin-liver Chip2 microphysiological systems model using the epidermal model, EpiDerm™, was reported previously to mimic application route-dependent metabolism of the hair dye, 4-amino-2-hydroxytoluene (AHT). Therefore, we evaluated the use of alternative skin models-SkinEthic™, EpiDermFT™ and PhenionFT™-for the same purpose. In static incubations, AHT permeation was similar using SkinEthic™ and EpiDerm™ models.

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All cosmetic ingredients registered in Europe must be evaluated for their safety using non-animal methods. Microphysiological systems (MPS) offer a more complex higher tier model to evaluate chemicals. Having established a skin and liver HUMIMIC Chip2 model demonstrating how dosing scenarios impact the kinetics of chemicals, we investigated whether thyroid follicles could be incorporated to evaluate the potential of topically applied chemicals to cause endocrine disruption.

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Significant advancements in the field of preclinical in vitro blood-brain barrier (BBB) models have been achieved in recent years, by developing monolayer-based culture systems towards complex multi-cellular assays. The coupling of those models with other relevant organoid systems to integrate the investigation of blood-brain barrier permeation in the larger picture of drug distribution and metabolization is still missing. Here, we report for the first time the combination of a human induced pluripotent stem cell (hiPSC)-derived blood-brain barrier model with a cortical brain and a liver spheroid model from the same donor in a closed microfluidic system (MPS).

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Microphysiological systems (MPS) are powerful tools for emulating human physiology and replicating disease progression in vitro. MPS could be better predictors of human outcome than current animal models, but mechanistic interpretation and in vivo extrapolation of the experimental results remain significant challenges. Here, we address these challenges using an integrated experimental-computational approach.

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Pharmaceutical and personal care industries require human representative models for testing to ensure the safety of their products. A major route of penetration into our body after substance exposure is via the skin. Our aim was to generate robust culture conditions for a next generation human skin-on-chip model containing neopapillae and to establish proof-of-concept testing with the sensitizer, cinnamaldehyde.

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Endocrine disruption by environmental chemicals continues to be a concern for human safety. The rat, a widely used model organism in toxicology, is very sensitive to chemical-induced thyroid perturbation, e.g.

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Thyroid hormones (THs) are crucial regulators of human metabolism and early development. During the safety assessment of plant protection products, the human relevance of chemically induced TH perturbations observed in test animals remains uncertain. European regulatory authorities request follow-up in vitro studies to elucidate human-relevant interferences on thyroid gland function or TH catabolism through hepatic enzyme induction.

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Article Synopsis
  • - The rapid development of new cellular and molecular technologies for assessing the safety of food, drugs, and personal care products is evolving, creating a need for their incorporation into regulatory processes.
  • - There are concerns that these emerging technologies may not have been adequately tested for regulatory application, which could hinder their effective use in safety assessments.
  • - To fully utilize these advancements, the regulatory community must devise strategies for evaluating these technologies and collaborate with developers, ensuring that regulatory decisions are informed and efficient.
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The first concepts for reproducing human systemic organismal biology were developed over 12 years ago. Such concepts, then called human- or body-on-a-chip, claimed that microphysiological systems would become the relevant technology platform emulating the physiology and morphology of human organisms at the smallest biologically acceptable scale and, therefore, would enable the selection of personalized therapies for any patient at unprecedented precision. Meanwhile, the first human organoids-stem cell-derived complex three-dimensional organ models that expand and self-organize -have proven that self-assembly of minute premature human organ-like structures is feasible, once the respective stimuli of ontogenesis are provided to human stem cells.

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Integration-free induced pluripotent stem cells from related human donors' exhibit great potential to the ongoing development of organ models. Blood cells from two different human donors were isolated, purified and reprogrammed into induced pluripotent stem cells. These induced pluripotent stem cell lines were characterized precisely for pluripotency markers (with the PluriTest and flow cytometry analysis) and their differentiation capacities into meso-, ecto- and endoderm.

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The integration-free iPSC lines TISSUi006-A and TISSUi007-A were generated by reprogramming blood cells with episomal vectors. The male human donors belong to a Caucasian family in which four additional family members donated and iPSC lines were generated. All iPSC lines within this family are approved for commercial use by donor consent.

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We used TissUse's HUMIMIC Chip2 microfluidic model, incorporating reconstructed skin models and liver spheroids, to investigate the impact of consumer-relevant application scenarios on the metabolic fate of the hair dye, 4-amino-2-hydroxytoluene (AHT). After a single topical or systemic application of AHT to Chip2 models, medium was analysed for parent and metabolites over 5 days. The metabolic profile of a high dose (resulting in a circuit concentration of 100 μM based on 100% bioavailability) of AHT was the same after systemic and topical application to 96-well EpiDerm™ models.

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Microphysiological systems (MPS) aim to mimic the dynamic microenvironment and the interaction between tissues. While MPS exist for investigating pharmaceuticals, the applicability of MPS for cosmetics ingredients is yet to be evaluated. The HUMIMIC Chip2 ("Chip2″), is the first multi-organ chip technology to incorporate skin models, allowing for the topical route to be tested.

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Access to complex in vitro models that recapitulate the unique markers and cell-cell interactions of the hair follicle is rather limited. Creation of scalable, affordable, and relevant in vitro systems which can provide predictive screens of cosmetic ingredients and therapeutic actives for hair health would be highly valued. In this study, we explore the features of the microfollicle, a human hair follicle organoid model based on the spatio-temporally defined co-culture of primary cells.

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Article Synopsis
  • * Using advanced synchrotron X-ray technology, the researchers analyzed the multi-elemental composition of peri-implant tissues, finding that cobalt (Co) and chromium (Cr) particles are present, while titanium (Ti) particles predominantly consist of titanium dioxide.
  • * The findings suggest that Co and Cr can accumulate in the bone marrow and affect the surrounding bone structure, highlighting the need for reevaluating the long-term impacts of metal implants on human health.
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A microfluidic multi-organ chip emulates the tissue culture microenvironment, enables interconnection of organ equivalents and overcomes interspecies differences, making this technology a promising and powerful tool for preclinical drug screening. In this study, we established a microfluidic chip-based model that enabled non-contact cocultivation of liver spheroids and renal proximal tubule barriers in a connecting media circuit over 16 days. Meanwhile, a 14-day repeated-dose systemic administration of cyclosporine A (CsA) alone or in combination with rifampicin was performed.

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Extrapolation of cell culture-based test results to in vivo effects is limited, as cell cultures fail to emulate organ complexity and multi-tissue crosstalk. Biology-inspired microphysiological systems provide preclinical insights into absorption, distribution, metabolism, excretion, and toxicity of substances in vitro by using human three-dimensional organotypic cultures. We co-cultured a human lung equivalent from the commercially available bronchial MucilAir culture and human liver spheroids from HepaRG cells to assess the potential toxicity of inhaled substances under conditions that permit organ crosstalk.

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Application of reconstructed human Skin (RhS) is a promising approach for the treatment of extensive wounds and for drug efficacy and safety testing. However, incorporating appendages, such as hair follicles, into RhS still remains a challenge. The hair follicle plays a critical role in thermal regulation, dispersion of sweat and sebum, sensory and tactile functions, skin regeneration, and repigmentation.

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The first microfluidic microphysiological systems (MPS) entered the academic scene more than 15 years ago and were considered an enabling technology to human (patho)biology in vitro and, therefore, provide alternative approaches to laboratory animals in pharmaceutical drug development and academic research. Nowadays, the field generates more than a thousand scientific publications per year. Despite the MPS hype in academia and by platform providers, which says this technology is about to reshape the entire in vitro culture landscape in basic and applied research, MPS approaches have neither been widely adopted by the pharmaceutical industry yet nor reached regulated drug authorization processes at all.

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UV light catalyzes the ozone formation from air pollutants, like nitrogen oxides. Since ozone reacts with cutaneous sebum lipids to peroxides and, thus, promotes inflammation, tumorigenesis, and aging, even broad-spectrum sunscreens cannot properly protect skin. Meanwhile, xanthophylls, like fucoxanthin, proved their antioxidant and cytoprotective functions, but the safety of their topical application in human cell-based models remains unknown.

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Four integration-free iPSC lines were generated by reprogramming peripheral blood mononuclear cells with episomal vectors. All four human donors (two male and two female donors) belong to one Caucasian family within three different generations with the age between 19-82 years. Additionally, all iPSC lines are approved for commercial use by donor consent.

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