Human skin equivalents (HSEs) are in vitro 3D-skin models that mimic many aspects of the native human skin (NHS) and can be a valuable tool. In this thesis, several (medium based) approaches have... Show moreHuman skin equivalents (HSEs) are in vitro 3D-skin models that mimic many aspects of the native human skin (NHS) and can be a valuable tool. In this thesis, several (medium based) approaches have been investigated to improve the barrier characteristics of this HSE to mimic that of NHS. Show less
Scheepens, K.M.J.; Marsidi, N.; Genders, R.E.; Horeman-Franse, T. 2022
After surgery, around 35% of patients experience problems of excessive scarring, causing disfiguring and impaired function. An incision placed in the wrong direction causes unnecessary skin tension... Show moreAfter surgery, around 35% of patients experience problems of excessive scarring, causing disfiguring and impaired function. An incision placed in the wrong direction causes unnecessary skin tension on the wound, resulting in increased collagen disposition and potentially hypertrophic scars. Currently, skin tension lines are used for incision planning. However, these lines are not universal and are a static representation of the skin tension that is in fact under influence of muscle action. By designing a new skin force measurement device the authors intend to make research on dynamic skin characteristics possible and to objectify incision planning and excision closure planning. The device applies a known compressive force to the skin in standardized directions and measures the displacement of the skin. This allows users to measure the skin reaction force in response to compression and to determine the optimal incision line or best wound closure direction. The device has an accuracy of 96% and a sensitivity of < 0.01 mm. It is compact, works non-invasively and standardizes measurement directions and is therefore an improvement over previously designed skin tensiometers. Show less
The skin is a surface that separates the inside from the outside while belonging to neither of them: it is a sheer instance of liminality where in the impervious borders of things are turned into... Show moreThe skin is a surface that separates the inside from the outside while belonging to neither of them: it is a sheer instance of liminality where in the impervious borders of things are turned into the porous boundaries of beings. The landscape, the skin of the world, is such a leaky boundary, which imbricates and implicates with terrestrial organisms while exceeding any organicity. By examining the recent photograph taken by contemporary Dutch artist Roosmarijn Pallandt (fig.1), this paper reads her representation of the landscape as the terraqueous skin of the world: an organelles organ that conduces the possibility of haptic perception through photography. To do this, it first draws on Tim Ingold’s theory of “surface vision” and then employs Edward S. Casey’s method of “liminology” to eventually apperceive the skin of the landscape as what Jean-Luc Nancy calls “a being-to-itself insofar as it is from side to side outside itself.” Show less
In this thesis, we aim to shed light on the diverse and often opposing roles of integrin α3β1 in cancer. Our work highlights that the role of α3β1 in cancer depends on time and place: the nature of... Show moreIn this thesis, we aim to shed light on the diverse and often opposing roles of integrin α3β1 in cancer. Our work highlights that the role of α3β1 in cancer depends on time and place: the nature of the cell environment (such as extracellular matrix composition), type of cancer and its driving mechanism, as well as the stage of the disease. We provide a new insight into the mechanisms behind the role of α3β1 in HER2-driven breast cancer and in DMBA/TPA-induced non-melanoma skin tumorigenesis. Show less
Nibberinga, P.H.; Goblyos, A.; Adriaans, A.E.; Cordfunke, R.A.; Ravensbergen, B.; Rietveld, M.H.; ... ; Ghalbzouri, A. el 2019
Skin bacterial colonization/infection is a frequent cause of morbidity in patients with chronic wounds and allergic/inflammatory skin diseases. This study aimed to develop a novel approach to... Show moreSkin bacterial colonization/infection is a frequent cause of morbidity in patients with chronic wounds and allergic/inflammatory skin diseases. This study aimed to develop a novel approach to eradicate meticillin-resistant Staphylococcus aureus (MRSA) from human skin. To achieve this, the stability and antibacterial activity of the novel LL-37-derived peptide P10 in four ointments was compared. Results indicate that P10 is chemically stable and antibacterial in hypromellose gel and Softisan-containing cream, but not in Cetomacrogol cream (with or without Vaseline), at 4 degrees C for 16 months. Reduction in MRSA counts on Leiden human epidermal models (LEMs) by P10 in hypromellose gel was greater than that of the peptide in Cetomacrogol cream or phosphate buffered saline. P10 did not show adverse effects on LEMs irrespective of the ointment used, while Cetomacrogol with Vaseline and Softisan cream, but not hypromellose gel or Cetomacrogol cream, destroyed MRSA-colonized LEMs. Taking all this into account, P10 in hypromellose gel dose-dependently reduced MRSA colonizing the stratum corneum of the epidermis as well as biofilms of this bacterial strain on LEMs. Moreover, P10 dose-dependently reduced MRSA counts on ex-vivo human skin, with P10 in hypromellose gel being more effective than P10 in Cetomacrogol and Softisan creams. P10 in hypromellose gel is a strong candidate for eradication of MRSA from human skin. (C) 2019 Elsevier B.V. and International Society of Chemotherapy. All rights reserved. Show less
Helder, R.W.J.; Boiten, W.A.; Dijk, R. van; Gooris, G.S.; El Ghalbzouri, A.; Bouwstra, J.A. 2019
Full thickness models (FTMs) are 3D-cultured human skin models that mimic many aspects of native human skin (NHS). However, their stratum corneum (SC) lipid composition differs from NHS causing a... Show moreFull thickness models (FTMs) are 3D-cultured human skin models that mimic many aspects of native human skin (NHS). However, their stratum corneum (SC) lipid composition differs from NHS causing a reduced skin barrier. The most pronounced differences in lipid composition are a reduction in lipid chain length and increased monounsaturated lipids. The liver-X-receptor (LXR) activates the monounsaturated lipid synthesis via stearoyl-CoA desaturase-1 (SCD-1). Therefore, the aim was to improve the SC lipid synthesis of FTMs by LXR deactivation. This was achieved by supplementing culture medium with LXR antagonist GSK2033. LXR agonist T0901317 was added for comparison. Subsequently, epidermal morphogenesis, lipid composition, lipid organization and the barrier functionality of these FTMs were assessed. We demonstrate that LXR deactivation resulted in a lipid composition with increased overall chain lengths and reduced levels of monounsaturation, whereas LXR activation increased the amount of monounsaturated lipids and led to a reduction in the overall chain length. However, these changes did not affect the barrier functionality. In conclusion, LXR deactivation led to the development of FTMs with improved lipid properties, which mimic the lipid composition of NHS more closely. These novel findings may contribute to design interventions to normalize SC lipid composition of atopic dermatitis patients. Show less
Prunier, C.; Chen, N.; Ritsma, L.; Vrisekoop, N. 2017
This thesis describes to which extent the skin reflects the aging process, with a specific focus on cellular senescence. Since the first descriptions of the growth arrested state of... Show more This thesis describes to which extent the skin reflects the aging process, with a specific focus on cellular senescence. Since the first descriptions of the growth arrested state of fibroblasts upon multiple replication rounds, cellular senescence has now emerged as a promising target to regulate the aging process in vivo as well. Here, we study whether fibroblast senescence in vitro is associated with in vivo donor characteristics such as chronological age and prevalence of disease. We further describe in this thesis whether senescence in skin tissue (in situ) is associated with other histological skin characteristics and with in vivo donor characteristics. Show less
Dissolving microneedles are an attractive approach for non-invasive delivery of drugs via the skin, particularly when the doses are in the microgram or low-milligram range. The aim of the study was... Show moreDissolving microneedles are an attractive approach for non-invasive delivery of drugs via the skin, particularly when the doses are in the microgram or low-milligram range. The aim of the study was to develop hyaluronan-based, monoclonal IgG-loaded microneedles for intradermal delivery enabling efficient penetration and rapid dissolution in the skin while preserving protein stability. Microscopic analysis showed successful preparation of sharp microneedles with the tip length of ~ 280 μm and with up to 10% (w/w) of IgG content. The water content of the microneedles was ~ 12% and was not affected by the protein content. The protein distribution was uniform within microneedle tips and individual arrays but some array-to-array variation of IgG level within a single preparation batch was detected. After dissolution of microneedle arrays in PBS, > 80% of protein was recovered and no conformational changes were detected by fluorescence spectroscopy. At submicron level, only weak and reversible interaction between HA and IgG was found by asymmetric flow field flow fractionation analysis after the dissolution of prepared microneedles. Although, the formation of insoluble micron-size particles was detected by flow imaging microscopy the IgG amount incorporated into these particles was negligible (< 5%). Finally, microneedles were able to penetrate into the epidermis of ex vivo human skin followed by the rapid dissolution of the microneedle tips in the skin. After 10 min of application, the majority of the original tip length was dissolved and IgG and hyaluronan were co-deposited until a depth of 150–200 μm in the skin. In conclusion, developed hyaluronan-based dissolving microneedles allow rapid non-invasive intradermal protein delivery. Show less
Formation of the epidermal barrier is a complex process involving the tight regulation of the expression of structural proteins, enzymes and cytokines, implementing different signaling pathways... Show moreFormation of the epidermal barrier is a complex process involving the tight regulation of the expression of structural proteins, enzymes and cytokines, implementing different signaling pathways depending on the differentiation stage of KC. Alterations of skin barrier formation occur as consequence of many skin diseases but can also be the primary event leading to skin diseases. Organotypic skin models have greatly contributed to delineate molecular mechanisms underlying the epidermal differentiation process. In this thesis we have adapted a human organotypic skin model to knock-down individual genes and study their impact on the differentiation of epidermal KC in vitro. Using this model we have provided new insights in the formation of the skin barrier of human skin. Show less
Garza-Rodea, A.S. de la; Knaan-Shanzer, S.; Bekkum, D.W. van 2011
The stratum corneum (SC), the thin uppermost layer of the skin, consists of dead flattened skin cells (corneocytes) embedded in a lipid matrix. The lipid matrix is considered to play a crucial role... Show moreThe stratum corneum (SC), the thin uppermost layer of the skin, consists of dead flattened skin cells (corneocytes) embedded in a lipid matrix. The lipid matrix is considered to play a crucial role in the skin barrier function. It consists of ceramides (CER), cholesterol (CHOL) and free fatty acids (FFA) forming crystalline lipid lamellae. From studies with native SC and SC lipid models much information has been gained on the phase behavior of the SC lipid matrix. However, little is known about the correlation between SC lipid organization and the permeability of the SC. This is difficult to investigate using native SC, due to its complex structure. Therefore SC lipids were casted on a porous membrane, resulting in a lipid organization and lamellar orientation similar to that in SC. This lipid membrane is referred to as the stratum corneum substitute (SCS). The SCS can be used to perform diffusion studies. Therefore, when modifying the lipid composition and thus the lipid organization in the SCS, it is possible to study the relationship between lipid organization and permeability. The main objectives of this thesis are 1) to investigate the influence of lipid organization on the barrier function in the SCS and 2) to obtain insights in the molecular organization within the unit cell of the lamellar phases in SC. Show less
Microneedle-based transcutaneous immunisation is an appealing alternative to the classical manner of injecting vaccines by intramuscular or subcutaneous route. Importantly, as a consequence of the... Show moreMicroneedle-based transcutaneous immunisation is an appealing alternative to the classical manner of injecting vaccines by intramuscular or subcutaneous route. Importantly, as a consequence of the fact that the skin is in direct contact with the environment and should protect the body against pathogens, it contains more antigen presenting cells, such as dendritic cells than the muscles or subcutaneous tissue and thereby offers the possibility to induce a more effective immune response. The combination of microneedles and adjuvanted subunit vaccines may offer effective vaccination whereas ensuring patient safety and vaccine application in a painless manner. The principal aim of this thesis was to design subunit vaccine formulations that can be combined with microneedles for transcutaneous immunisation. The approaches described in this thesis have generated new insights into the main requirements for transcutaneous immunisation. Microneedles definitively have the potential to be an excellent utensil for the delivery of vaccines into the skin. However, the skin is a very elastic organ and the actual conduits formed by microneedle pre-treatment will be considerably smaller than the diameter of the microneedles. Therefore, a small antigen-adjuvant entity is the preferred formulation, as it will be transported efficiently through the microneedle conduits while it retains the co-delivery of antigen and adjuvant. Show less
Sunlight has many beneficial effects. However, from a biological point of view, solar UV radiation has also detrimental effects, especially at high doses of exposure. Because of its genotoxic... Show moreSunlight has many beneficial effects. However, from a biological point of view, solar UV radiation has also detrimental effects, especially at high doses of exposure. Because of its genotoxic properties, UV radiation plays an important role in the induction of skin cancer. In the last decennia, the incidence of skin cancer is rapidly increasing. This can partly be explained by an ageing population. However, the rise in skin cancer incidence appears to be primarily due to a change in human lifestyle in which sunbathing has become very popular. Our skin is continuously challenged by UV radiation, which may lead to irreversible damage. In order to withstand sustained physical, chemical and biological damage from the environment, among which UV radiation, the skin is continuously renewed. The regenerative capacity of skin is conferred by stem cells, which persist throughout the organism__s lifetime. Because of their long residency and unlimited capacity to replicate, stem cells might accumulate DNA damage and generate the multiple genetic lesions necessary for tumour development, despite efficient cellular defence mechanisms against DNA damage. Thus, stem cells may play an important role in carcinogenesis. The aim of this study is to investigate the role of stem cells in skin carcinogenesis. Show less
