| 1. |
- Gustafson, Carl-Johan, et al.
(författare)
-
Employing human keratinocytes cultured on macroporous gelatin spheres to treat full thickness-wounds : an in vivo study on athymic rats.
- 2007
-
Ingår i: Burns. - : Elsevier BV. - 0305-4179 .- 1879-1409. ; 33:6, s. 726-35
-
Tidskriftsartikel (refereegranskat)abstract
- Providing cutaneous wounds with sufficient epidermis to prevent infections and fluid loss is one of the most challenging tasks associated with surgical treatment of burns. Recently, application of cultured keratinocytes in this context has allowed this challenge to be met without several of the limitations connected with the use of split-thickness skin grafts. The continuous development of this novel approach has now revealed that transplantation of cultured autologous keratinocytes as single-cell suspensions exhibits several advantages over the use of cultured epidermal grafts. However, a number of methodological problems remain to be solved, primarily with regards to the complexity of culturing these cells; loss of viability and other negative effects during their preparation and transportation; the relatively long period of time required following transplantation to obtain a sufficiently protective epidermis. In the present investigation we attempted to eliminate these limitations by culturing the keratinocytes on macroporous gelatin spheres. Accordingly, the efficacies of normal human keratinocytes in single-cell suspension or growing on macroporous gelatin spheres, as well as of split-thickness skin grafts in healing wounds on athymic rats were compared. Human keratinocytes were found to adhere and proliferate efficiently both on the surface and within the pores of such spheres. Transplantation of such cells adherent to the spheres resulted in significantly more rapid formation of a stratified epidermis than did transplantation of single-cell suspensions or spheres alone. Twenty-three days after transplantation, the epidermis formed from the cells bound to the spheres was not as thick as the epidermis on wounds covered with split-thickness skin grafts, but significantly thicker than on wounds to which single-cell suspensions, spheres alone or no transplant at all was applied. Furthermore, fluorescence in situ hybridisation revealed that the transplanted keratinocytes, both those adherent to gelatin spheres and those in single-cell suspension, were components of the newly formed epidermis. These findings indicate that application of biodegradable macroporous spheres may prove to be of considerable value in designing cell-based therapies for the treatment of acute and persistent wounds.
|
|
| 2. |
|
|
| 3. |
- Baş, Yağmur, et al.
(författare)
-
Preparation and Characterization of Softwood and Hardwood Nanofibril Hydrogels: Toward Wound Dressing Applications
- 2023
-
Ingår i: Biomacromolecules. - : American Chemical Society (ACS). - 1525-7797 .- 1526-4602. ; 24:12, s. 5605-5619
-
Tidskriftsartikel (refereegranskat)abstract
- Hydrogels of cellulose nanofibrils (CNFs) are promising wound dressing candidates due to their biocompatibility, high water absorption, and transparency. Herein, two different commercially available wood species, softwood and hardwood, were subjected to TEMPO-mediated oxidation to proceed with delignification and oxidation in a one-pot process, and thereafter, nanofibrils were isolated using a high-pressure microfluidizer. Furthermore, transparent nanofibril hydrogel networks were prepared by vacuum filtration. Nanofibril properties and network performance correlated with oxidation were investigated and compared with commercially available TEMPO-oxidized pulp nanofibrils and their networks. Softwood nanofibril hydrogel networks exhibited the best mechanical properties, and in vitro toxicological risk assessment showed no detrimental effect for any of the studied hydrogels on human fibroblast or keratinocyte cells. This study demonstrates a straightforward processing route for direct oxidation of different wood species to obtain nanofibril hydrogels for potential use as wound dressings, with softwood having the most potential.
|
|
| 4. |
- Berglund, Linn, et al.
(författare)
-
Self-Assembly of Nanocellulose Hydrogels Mimicking Bacterial Cellulose for Wound Dressing Applications
- 2023
-
Ingår i: Biomacromolecules. - : American Chemical Society (ACS). - 1525-7797 .- 1526-4602. ; 24:5, s. 2264-2277
-
Tidskriftsartikel (refereegranskat)abstract
- The self-assembly of nanocellulose in the form of cellulose nanofibers (CNFs) can be accomplished via hydrogen-bonding assistance into completely bio-based hydrogels. This study aimed to use the intrinsic properties of CNFs, such as their ability to form strong networks and high absorption capacity and exploit them in the sustainable development of effective wound dressing materials. First, TEMPO-oxidized CNFs were separated directly from wood (W-CNFs) and compared with CNFs separated from wood pulp (P-CNFs). Second, two approaches were evaluated for hydrogel self-assembly from W-CNFs, where water was removed from the suspensions via evaporation through suspension casting (SC) or vacuum-assisted filtration (VF). Third, the W-CNF-VF hydrogel was compared to commercial bacterial cellulose (BC). The study demonstrates that the self-assembly via VF of nanocellulose hydrogels from wood was the most promising material as wound dressing and displayed comparable properties to that of BC and strength to that of soft tissue.
|
|
| 5. |
- Eskilson, Olof, 1992-, et al.
(författare)
-
Nanocellulose composite wound dressings for real-time pH wound monitoring
- 2023
-
Ingår i: Materials Today Bio. - : Elsevier. - 2590-0064. ; 19
-
Tidskriftsartikel (refereegranskat)abstract
- The skin is the largest organ of the human body. Wounds disrupt the functions of the skin and can have catastrophic consequences for an individual resulting in significant morbidity and mortality. Wound infections are common and can substantially delay healing and can result in non-healing wounds and sepsis. Early diagnosis and treatment of infection reduce risk of complications and support wound healing. Methods for monitoring of wound pH can facilitate early detection of infection. Here we show a novel strategy for integrating pH sensing capabilities in state-of-the-art hydrogel-based wound dressings fabricated from bacterial nanocellulose (BC). A high surface area material was developed by self-assembly of mesoporous silica nanoparticles (MSNs) in BC. By encapsulating a pH-responsive dye in the MSNs, wound dressings for continuous pH sensing with spatiotemporal resolution were developed. The pH responsive BC-based nanocomposites demonstrated excellent wound dressing properties, with respect to conformability, mechanical properties, and water vapor transmission rate. In addition to facilitating rapid colorimetric assessment of wound pH, this strategy for generating functional BC-MSN nanocomposites can be further be adapted for encapsulation and release of bioactive compounds for treatment of hard-to-heal wounds, enabling development of novel wound care materials.
|
|
| 6. |
- Junker, Johan, 1980-, et al.
(författare)
-
Adipogenic, Chondrogenic and Osteogenic Differentiation of ClonallyDerived Human Dermal Fibroblasts
- 2010
-
Ingår i: Cells Tissues Organs. - Basel : Karger AG. - 1422-6405 .- 1422-6421. ; 191:2, s. 105-118
-
Tidskriftsartikel (refereegranskat)abstract
- The apparent need of an autologous cell source for tissueengineering applications has led researchers to explore thepresence of cells with stem cell plasticity in several humantissues. Dermal fibroblasts (FBs) are easy to harvest, expandin vitro and store, rendering them plausible candidates forcell-based therapies. The aim of the present study was toobserve the effects of adipogenic, chondrogenic and osteogenicinduction media on the phenotype of human FBs.Human preadipocytes obtained from fat tissue have beenproposed as an adult stem cell source with suitable characteristics,and were used as control cells in regard to their differentiationpotential. Routine staining, immunohistochemicalanalysis and alkaline phosphatase assay were employed,in order to study the phenotypic shift. FBs were shown topossess multilineage potential, giving rise to fat-, cartilageandbone-like cells. To exclude contaminant progenitor cellsor cell fusion giving rise to tissue with adipocyte-, chondrocyte-and osteoblast-like cells, single-cell cloning was performed.Single-cell-cloned FBs (sccFBs) displayed a similardifferentiation potential as primary-culture FBs. The pres-ence of ‘stem-cell-specific’ surface antigens was analyzedusing flow cytometry. The results reveal that sccFBs haveseveral of the markers associated with cells exhibiting stemcell plasticity. The findings presented here are corroboratedby the findings of other groups, and suggest the use of humandermal FBs in cell-based therapies for the reconstructionof fat, cartilage and bone.
|
|
| 7. |
- Junker, Johan, 1980-, et al.
(författare)
-
Gene Expression Analysis of Adipogenic, Chondrogenic and Osteogenic Induced Human Dermal Fibroblasts
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- The use of adult stem cells in tissue engineering applications is a promising alternativewhen the possibility of acquiring autologous cells for transplantation is limited. Even so, theadult stem cell populations identified up to this point are far from optimal in aspects ofharvest and culture expansion. With the recent suggestion of stem cell plasticity inherent inhuman dermal fibroblasts, a new plausible candidate for use as cell source in tissuereconstruction has emerged. Fibroblast cultures can be induced to differentiate towardsadipocyte, chondrocyte and osteoblast-like cells in vitro, by the use of induction media. Thepresent works utilizes Affymetrix full expression micro array to identify if genes commonlyexpressed in stem cells differentiating towards the above-mentioned lineages also areexpressed in induced fibroblasts. Several genes important for differentiation andmaintenance of an adipose, cartilage or bone phenotype were found up-regulated in theinduced cultures. The results presented here provide further evidence for the plasticity ofhuman dermal fibroblasts, and their possible use in tissue engineering and reconstructivesurgery.
|
|
| 8. |
- Junker, Johan, 1980-
(författare)
-
Human Dermal Fibroblasts in Tissue Engineering
- 2009
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The loss or failure of tissues and/or organs is one of the most frequent problems in modern healthcare. The field of tissue engineering applies the principles of biology and engineering in order to develop functional substitutes for damaged tissues. Tissue engineering contains elements of medicine, material science and engineering with major components in focus being cells, biomaterials and soluble factors. All three components may be required for the development of clinical treatments.The usage of autologous tissue specific cells for clinical treatment is often not feasible due to poor growth kinetics or unstable phenotypes of the cells. Furthermore, lack of availability of healthy tissue that can be biopsied is a major problem in many applications. One approach to overcome this problem is to use adult stem cells which have the capacity to give rise to several different cell types. Although promising, adult stem cells have major impediments for use in several tissue engineering applications. The difficulties associated with harvest, culture and storage render problems in the development of clinically relevant procedures.During the last years, the inherent plasticity of differentiated somatic cells has been demonstrated. One of the easiest human cell types to obtain, expand and store is the dermal fibroblast. Recent reports indicate that dermal fibroblasts can be induced to differentiate towards several distinct mesenchymal lineages in vitro.The main aim of this thesis was to investigate the inherent stem cell plasticity of human dermal fibroblasts and explore their possible usefulness in tissue engineering applications. The papers included in this thesis employ routine and immunohistochemical staining, enzyme activity assay, analysis of low density lipoprotein incorporation, capillary-like network formation assay and full expression micro array analysis.Fibroblasts were shown to differentiate towards adipocyte, chondrocyte, endothelial and osteoblast-like cell types in vitro. The differentiation from fibroblasts to myofibroblasts in burn scar tissue upon stimulation by mechanical tension was also demonstrated. Adipogenic, chondrogenic and osteogenic induced fibroblasts display the upregulation of several genes associated with adipocytes, chondrocytes and osteoblasts.
|
|
| 9. |
- Junker, Johan P E, 1980-, et al.
(författare)
-
Mechanical tension stimulates the transdifferentiation of fibroblasts into myofibroblasts in human burn scars
- 2008
-
Ingår i: Burns : journal of the International Society for Burn Injuries. - : Elsevier BV. - 1879-1409. ; 34:7, s. 942-6
-
Tidskriftsartikel (refereegranskat)abstract
- Scar formation as a result of burn wounds leads to contraction of the formed granulation tissue, which causes both aesthetic and functional impairment for the patient. Currently, the main treatment methods focus on stretching to prevent tissue contraction. The myofibroblasts play a key role in the contraction of granulation tissue during scar formation, but their presence should normally decrease after wound re-epithelialization. In hypertrophic scars the myofibroblasts persist and is believed to cause further hypertrophy. Previous studies have shown that mechanical tension leads to increased myofibroblast numbers in granulation tissue. In order to evaluate the effect mechanical tension as a result of stretching has on the number of myofibroblasts in burn wound scars, an in vitro model was used. This model used human burn scar biopsies which were stretched and examined after 1 and 6 days to evaluate the effect on the number of myofibroblasts. The stretching caused an increase in the number of myofibroblasts after mechanical stimulation. This indicates that mechanical stimulation using stretching induces fibroblast to myofibroblast transdifferentiation, thus underlining the importance of further investigations of optimal methods of this regime for treating burn scars.
|
|
| 10. |
- Junker, Johan, 1980-, et al.
(författare)
-
Prehospital Monitoring of Vital Parameters Using a Novel Device - RespiHeart
- 2017
-
Ingår i: Prehospital and Disaster Medicine. - : Cambridge University Press. - 1049-023X .- 1945-1938. ; 32:Suppl. 1, s. S165-S166
-
Tidskriftsartikel (refereegranskat)abstract
- Study/Objective: The study aims at validating a novel device (RespiHeart) for monitoring vital parameters in traumatically injured patients. Background: There is a need for a simple-to-use method for monitoring of vital parameters in the prehospital setting. RespiHeart is a small medical device that is attached to the sternum. It sends light of defined wavelengths into the underlying vasculature, and measures the reflected light. The resulting signals are then treated using proprietary algorithms to obtain heart rate and respiratory rate. The device has the capability to also measure oxygen saturation, temperature and movement. Methods: The device was tested during training sessions for medical personnel, where various traumatic wounds were inflicted on anesthetized pigs. The training was primarily focused on teaching acute lifesaving interventions. The RespiHeart device was applied to the animal and used to monitor vital parameters throughout the training session. A total of 22 animals were included in the study. The data gathered from Respiheart were compared to results from a pulse oximeter and ventilator connected to the animal. Statistical comparison were performed using linear regression and Bland-Altman plots to analyze agreement of methods. Results: The heart rate as measured by the pulse oximeter was correlated to the rate reported by RespiHeart. The R2 was 0.9946 with a p-value of less than 0.0001. Bland-Altman analysis of heart rate revealed a bias of -0.06127 (95% CI -2.219- 2.097). The respiratory rate as set on the ventilator was correlated to the rate reported by RespiHeart. The R2 was 0.9978 with a p-value of less than 0.0001. Bland-Altman analysis of respiratory rate revealed a bias of -0.008584 (95% CI -0.42-0.4028). Conclusion: The results obtained in this study demonstrate a high degree of correlation between the data obtained from RespiHeart and the pulse oximeter and ventilator. This renders RespiHeart as a promising device for prehospital use.
|
|
