10 results on '"Lönnqvist, Susanna"'
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2. Ferroelectric surfaces for cell release
- Author
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Toss, Henrik, Lönnqvist, Susanna, Nilsson, David, Sawatdee, Anurak, Nissa, Josefin, Fabiano, Simone, Berggren, Magnus, Kratz, Gunnar, and Simon, Daniel T.
- Published
- 2017
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3. Tracking keratinocytes and melanocytes using carboxyfluorescein hydroxysuccinimidyl ester staining
- Author
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Lönnqvist, Susanna, Junker, Johan P. E., Sedell, Maria, Nyman, Erika, and Kratz, Gunnar
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Keratinocytes ,Physiology ,Imaging Techniques ,Cell Survival ,Cell- och molekylärbiologi ,Science ,Fluorescent Antibody Technique ,Succinimides ,Surgical and Invasive Medical Procedures ,Research and Analysis Methods ,Epithelium ,Fluorescence Microscopy ,Animal Cells ,Tissue Repair ,Fluorescence Imaging ,Medicine and Health Sciences ,Humans ,Chromatophores ,Fluorescent Dyes ,Staining ,Microscopy ,Wound Healing ,Chemical Compounds ,Biology and Life Sciences ,Cell Staining ,Light Microscopy ,Epithelial Cells ,Esters ,Cell Biology ,Fluoresceins ,Immunohistochemistry ,Skin Grafting ,Chemistry ,Biological Tissue ,Microscopy, Fluorescence ,Specimen Preparation and Treatment ,Physical Sciences ,Melanocytes ,Medicine ,Cellular Types ,Anatomy ,Physiological Processes ,Plastic Surgery and Reconstructive Techniques ,Cell and Molecular Biology ,Research Article - Abstract
Introduction The treatment of burn wounds and hypopigmentation conditions often require autologous transplantation of keratinocytes and melanocytes. Tracking transplanted cells to ascertain their contribution to tissue recapitulation presents a challenge. This study demonstrates a methodology based on passive staining with carboxyfluorescein hydroxysuccinimidyl ester ( CFSE) that enables localization of cells in tissue sections to investigate the fate of transplanted cells in wound re-epithelialisation. Methods Viability and migration of CFSE-stained keratinocytes and melanocytes were investigated using viability staining and scratch assays, while proliferation of cells was measured using flow cytometry. In addition, CFSE-stained keratinocytes and melanocytes were transplanted to a human ex vivo wound model, either in suspension, or with the aid of macroporous gelatine microcarriers. Wounds were analysed seven, 14 and 21 days post transplantation using cryosectioning and fluorescence microscopy. Sections from wounds with transplanted co-cultured keratinocytes and melanocytes were stained for pancytokeratin to distinguish keratinocytes. Results CFSE-staining of keratinocytes and melanocytes did not affect the viability, migration or proliferation of the cells. Transplanted cells were tracked in ex vivo wounds for 21 days, illustrating that the staining had no effect on wound re-epithelialisation. In conclusion, this study presents a novel application of CFSE-staining for tacking transplanted primary human keratinocytes and melanocytes. Funding Agencies|Region Ostergotland [LIO-695901]
- Published
- 2019
4. Applications of human skin in vitro
- Author
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Lönnqvist, Susanna
- Subjects
integumentary system ,Klinisk medicin ,Clinical Medicine ,Clinical Science ,Klinisk vetenskap - Abstract
Chronic wounds are a substantial problem in today’s health care and place significant strains on the patient. Successful modelling of the wound healing process is pivotal for the advancement of wound treatment research. Wound healing is a dynamic and multifactorial process involving all constituents of the skin. The progression from haemostasis and inflammation to proliferation of epidermal keratinocytes and dermal fibroblasts, and final scar maturation can be halted and result in a chronic wound that fails to re-epithelialise. The wound healing process constitutes an example of dynamic reciprocity in tissue where cellular changes take place on cues from the extracellular matrix and vice versa when tissue homeostasis is disturbed. The extracellular matrix provides a structural context for the resident cells and the epidermal keratinocytes, and a functioning interplay between the two tissue compartments is crucial for successful wound healing to take place. Work included in this thesis has applied viable human full thickness skin in vitro to investigate the re-epithelialisation process and barrier function of intact skin.The use of full thickness skin in vitro can take into account the contextual aspect of the process where the epidermal keratinocytes are activated and obtain a migratory phenotype, and are continuously dependent on the cues from the extracellular matrix and support of the dermis. When utilising skin for studies on re-epithelialisation, circular standardised full thickness wounds were created and cultured for up to four weeks in tissue culture. In paper I, the organisation of a thick neoepidermis was investigated in the in vitro wound healing model when resident cells were provided with a porous suspended three dimensional gelatin scaffold. In paper II we investigated the use of a fluorescent staining conventionally used for proliferation studies to facilitate the tracing of transplanted epidermal cells in in vitro wounds, in order to improve and expand the use of the model. In paper III the model was utilised to investigate the treatment approach of acidification of wounds to evaluate the suitability of such intervention in regards to keratinocyte function and re-epithelialisation. Studies on re-epithelialisation with the aid of the in vitro wound healing model provided insight in neoepidermal structure with porous gelatin scaffolding in the wound, a novel methodological approach to tracing cells and response to constrained wound healing environment. In paper IV, intact human skin was evaluated for modelling the cytotoxic response after exposure to a known irritant compound. To study barrier function, intact skin was exposed to irritants by restricting exposure topically, and full thickness skin in vitro was found suitable for modelling cytotoxicity responses. Employing human full thickness skin in vitro makes use of the actual target tissue of interest with epidermal and dermal cells, and full barrier function.
- Published
- 2016
5. Non-occlusive topical exposure of human skin in vitro as model for cytotoxicity testing of irritant compounds.
- Author
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Lönnqvist, Susanna, Briheim, Kristina, and Kratz, Gunnar
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CELL-mediated cytotoxicity , *IRRITANTS (Drugs) , *SODIUM dodecyl sulfate , *ANIMAL models in research , *TETRAZOLIUM - Abstract
Testing of irritant compounds has traditionally been performed on animals and human volunteers. Animal testing should always be restricted and for skin irritancy mice and rabbits hold poor predictive value for irritant potential in humans. Irritant testing on human volunteers is restricted by the duration subjects can be exposed, and by the subjectivity of interpreting the visual signs of skin irritation. We propose an irritant testing system using viable human full thickness skin with the loss of cell viability in the exposed skin area as end point measurement. Skin was exposed to sodium dodecyl sulfate (SDS) at 20% concentration by non-occluded topical exposure to establish a positive control response and subsequent test compounds were statistically compared with the 20% SDS response. Cell viability and metabolism were measured with 3-(4,5-dimethyl-thiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. The model presents correlation between increased concentration of SDS and decreased viability of cells in the exposed skin area (R2 = 0.76). We propose the model to be used for cytotoxicity testing of irritant compounds. With fully intact barrier function, the model comprises all cells present in the skin with quantifiable end point measurement. [ABSTRACT FROM AUTHOR]
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- 2016
- Full Text
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6. Matrix Addressing of an Electronic Surface Switch Based on a Conjugated Polyelectrolyte for Cell Sorting.
- Author
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Persson, Kristin M., Lönnqvist, Susanna, Tybrandt, Klas, Gabrielsson, Roger, Nilsson, David, Kratz, Gunnar, and Berggren, Magnus
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CELLS , *POLYELECTROLYTES , *KERATINOCYTES , *FIBROBLASTS , *CONJUGATED polymers , *POLYMER films , *PHOTOLITHOGRAPHY - Abstract
Spatial control of cell detachment is potentially of great interest when selecting cells for clonal expansion and in order to obtain a homogeneous starting population of cells aimed for tissue engineering purposes. Here, selective detachment and cell sorting of human primary keratinocytes and fibroblasts is achieved using thin films of a conjugated polymer. Upon electrochemical oxidation, the polymer film swells, cracks, and finally detaches taking cells cultured on top along with it. The polymer can be patterned using standard photolithography to fabricate a cross-point matrix with polymer pixels that can be individually addressed and thus detached. Detachment occurs above a well-defined threshold of +0.7 V versus Ag/AgCl, allowing the use of a relatively simple and easily manufactured passive matrix-addressing configuration, based on a resistor network, to control the cell-sorting device. [ABSTRACT FROM AUTHOR]
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- 2015
- Full Text
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7. Influence of acidic pH on keratinocyte function and re-epithelialisation of human in vitro wounds.
- Author
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Lönnqvist, Susanna, Emanuelsson, Peter, and Kratz, Gunnar
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CHRONIC wounds & injuries , *KERATINOCYTES , *SURGICAL dressings , *DIAGNOSTIC use of polymerase chain reaction , *WOUND healing , *THERAPEUTICS - Abstract
Background: Chronic wounds are one of the greatest challenges for the healthcare system. Today, a plethora of dressings are used in the treatment of these wounds, each with specific influence on the wound environment. Due to differences in the permeability of the dressings the use will result in differences in the pH balance in the wound bed. However, little is known about how changes in the pH in the wound environment affect the different phases of the healing process. Aim: The aim of the present study was to investigate the effects of acidic pH on the regeneration phase by studying keratinocyte function in vitro and re-epithelialisation in an in vitro model of human skin. Results:In vitro assays showed reduced viability and migration rates in human keratinocytes when pH was lowered. Real time PCR revealed differential expression of genes related to wound healing and environmental impairment. Tissue culture showed no re-epithelialisation of wounds subjected to pH 5.0 and moderate re-epithelialisation at pH 6.0, compared to controls at pH 7.4. Conclusion: The results indicate that lowering pH down to pH 5.0 in wounds is counterproductive in aspect of keratinocyte function which is crucial for successful wound healing. [ABSTRACT FROM AUTHOR]
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- 2015
- Full Text
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8. Biodegradable Gelatin Microcarriers Facilitate Re-Epithelialization of Human Cutaneous Wounds - An In Vitro Study in Human Skin.
- Author
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Lönnqvist, Susanna, Rakar, Jonathan, Briheim, Kristina, and Kratz, Gunnar
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SKIN injuries , *GELATIN , *BIODEGRADABLE products , *WOUND healing , *KERATINOCYTES , *IMMUNOHISTOCHEMISTRY - Abstract
The possibility to use a suspended tridimensional matrix as scaffolding for re-epithelialization of in vitro cutaneous wounds was investigated with the aid of a human in vitro wound healing model based on viable full thickness skin. Macroporous gelatin microcarriers, CultiSpher-S, were applied to in vitro wounds and cultured for 21 days. Tissue sections showed incorporation of wound edge keratinocytes into the microcarriers and thicker neoepidermis in wounds treated with microcarriers. Thickness of the neoepidermis was measured digitally, using immunohistochemical staining of keratins as epithelial demarcation. Air-lifting of wounds enhanced stratification in control wounds as well as wounds with CultiSpher-S. Immunohistochemical staining revealed expression of keratin 5, keratin 10, and laminin 5 in the neoepidermal component. We conclude that the CultiSpher-S microcarriers can function as tissue guiding scaffold for re-epithelialization of cutaneous wounds. [ABSTRACT FROM AUTHOR]
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- 2015
- Full Text
- View/download PDF
9. Differentiation of human dermal fibroblasts towards endothelial cells.
- Author
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Junker JP, Lönnqvist S, Rakar J, Karlsson LK, Grenegård M, and Kratz G
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- Cell Lineage, Cells, Cultured, Gene Expression Profiling, Gene Expression Regulation, Developmental, Genome, Human, Humans, Serum, Tissue Engineering, Cell Differentiation, Dermis cytology, Endothelial Cells cytology, Fibroblasts cytology
- Abstract
The ultimate goal of vascular tissue engineering is the production of functional grafts for clinical use. Difficulties acquiring autologous endothelial cells have motivated the search for alternative cell sources. Differentiation of dermal fibroblasts towards several mesenchymal lineages as well as endothelial cells has been proposed. The aim of the present study was to investigate the endothelial differentiation capacity of human dermal fibroblasts on a gene expression, protein expression and functional physiological level. Endothelial differentiation of fibroblasts was induced by culturing cells in 30% human serum, but not in fetal calf serum. Expression of proteins and genes relevant for endothelial function and differentiation was increased after induction. Furthermore, fibroblasts exposed to 30% human serum displayed increased uptake of low-density lipoprotein and formation of capillary-like networks. The results of this study may have an impact on cell sourcing for vascular tissue engineering, and the development of methods for vascularization of autologous tissue engineered constructs., (Copyright © 2013 International Society of Differentiation. Published by Elsevier B.V. All rights reserved.)
- Published
- 2013
- Full Text
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10. Interpreted gene expression of human dermal fibroblasts after adipo-, chondro- and osteogenic phenotype shifts.
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Rakar J, Lönnqvist S, Sommar P, Junker J, and Kratz G
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- Adipocytes cytology, Cell Differentiation, Cells, Cultured, Chondrocytes cytology, Dermis cytology, Fibroblasts cytology, Gene Expression Regulation, Developmental, Humans, Osteoblasts cytology, Phenotype, Plastic Surgery Procedures, Tissue Engineering, Adipogenesis, Chondrogenesis, Dermis metabolism, Fibroblasts metabolism, Gene Expression, Osteogenesis
- Abstract
Autologous cell-based therapies promise important developments for reconstructive surgery. In vitro expansion as well as differentiation strategies could provide a substantial benefit to cellular therapies. Human dermal fibroblasts, considered ubiquitous connective tissue cells, can be coaxed towards different cellular fates, are readily available and may altogether be a suitable cell source for tissue engineering strategies. Global gene expression analysis was performed to investigate the changes of the fibroblast phenotype after four-week inductions toward adipocytic, osteoblastic and chondrocytic lineages. Differential gene regulation, interpreted through Gene Set Enrichment Analysis, highlight important similarities and differences of induced fibroblasts compared to control cultures of human fibroblasts, adipocytes, osteoblasts and articular chondrocytes. Fibroblasts show an inherent degree of phenotype plasticity that can be controlled to obtain cells supportive of multiple tissue types., (Copyright © 2012 International Society of Differentiation. Published by Elsevier B.V. All rights reserved.)
- Published
- 2012
- Full Text
- View/download PDF
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