Wound healing in skin is a complex process involving inflammatory responses, cell proliferation and migration, and extracellular matrix deposition. While, all-trans retinoic acid (ATRA) is believed to promote wound healing in skin, there are contradictory reports on its effect in both in vivo and in vitro studies. This study aimed at investigating the effects of ATRA at a concentration of 1μM (in DMSO) on cell migration and proliferation in ‘wound’ closure. A HaCaT and a HDF cell line as well as a co-culture of both cell lines were utilized. The cultures were maintained in DMEM supplemented with 5% fetal bovine serum incubated at 37ºC in a 5% CO2 in air humidified incubator. Scratch ‘wounding’ of the HaCaT culture and the co-culture were carried out prior to treatment with ATRA or its controls [DMSO (vehicle control) or DMEM (untreated control)]. ATRA did not have a significant effect on cell proliferation in either the HaCaT or HDF cultures or in the co-cultures. DMSO inhibited proliferation in the HDF cultures and in the co-cultures, while there was no effect on the HaCaT cultures. In addition, ATRA had no significant effect on ‘cell migration’ during ‘wound’ closure in both the HaCaT culture and the co-culture. However, DMSO appeared to be inhibitory to migration of cells in both cultures as there was a significant decrease in migration in cultures grown in DMSO when compared to ATRA treatment. The failure of ATRA to promote cell migration and proliferation during ‘wound’ closure in the HaCaT culture and the co-culture would seem to suggest that the activity of ATRA was compromised by DMSO.

Thesis (Ph. D.)--University of Washington, 1995. / Vita. Includes bibliographical references (leaves [248]-266).

M.Tech. / The skin accounts for 14 percent of the total body weight and is the largest organ in the body (Edward & MacKie, 2001). Our skin serves as a protective barrier against the outside world, thus any break in it must be rapidly and efficiently mended. A wound may be defined as any disruption of the tissues of the body caused by injury (Vardaxis, 1995). Commonly recognised examples include bruises, grazes, incisions, ulcers and burns. While some wounds heal easily others become fatally infected. According to statistics in the United States, for the year 2000, approximately five million Americans suffered from chronic open sores that could become seriously infected (UMMC, 2000). Unfortunately, neither Statistics South Africa (STATS SA) nor the South African Medical Research Council have statistics on open sores. The aim of this study was to determine the effectiveness of Low Level Laser Therapy (LLLT) and Calendula officinalis 3cH respectively as treatment protocols on wound healing in injured human skin fibroblasts (HSF) in-vitro. Furthermore the study aimed to investigate the effectiveness of a combination of both treatment modalities on wound healing. Commercially available human skin fibroblast (HSF) cell lines (CRL1502 WS1) were obtained from the American Type Culture Collection (ATCC). Each week these fibroblasts were subcultured from 75cm² flasks to six, 3.3cm diameter culture plates. To simulate mechanical disruption of the cells a central scratch was performed across the confluent monolayer of fibroblasts according to the method described by Rigau et al., (1995), using a sterile Pasteur pipette of 2mm in diameter. Each scratch was irregular and the “wounds” ranged from 1-2mm in diameter. Five of the plates received the aforementioned scratch. Thereafter only four of the plates received a specific treatment modality. The remaining two plates served as controls. To assess the effectiveness of each treatment modality, wound healing was measured using the following techniques: cell morphology using an inverted microscope (Olympus CKX41) to monitor cell migration and wound closure. Cell viability was measured using the Trypan blue and ATP cell viability assay. Cytotoxicity was measured using the Lactate dehydrogenase (LDH) membrane assay. Apoptosis of cells was detected with a Caspase assay. Alkaline phosphatase (ALP) assay was used as a marker for wound healing. Interleukin-6 (IL-6) is a cytokine released early in wound healing and was used to measure cell proliferation. The experimental procedure was designed to determine if there was a difference in the wound healing outcome if cells were exposed to a single treatment application or a double treatment application with a 24 hour interval. The single treatment protocol was repeated four times (n=4) while the double treatment protocol was repeated six times (n=6). The data for both experimental procedures was analysed using Sigma Plot 8.0 computer software. The student t-test was utilised to examine the effect that the treatments (independent variables) had on the various aspects of wound healing (dependent variables). In each case a statistical difference was identified as P< 0.05. Morphological changes indicate that a double treatment application of Calendula officinalis 3cH increases wound closure on wounded HSF cells in-vitro. Laser irradiation too showed morphological signs of increased wound closure for HSF cells receiving a double exposure. However, a synergistic relationship, based on morphology, was not established when combining the two treatments. Based on statistical analysis the results showed that neither Calendula officinalis 3cH nor laser irradiation, as singular or combination treatment modalities, improved wound healing in wounded HSF cells in-vitro. However, findings were encouraging and minor changes evident on a cellular level may be more significant at a systemic level.

Yes / Wound healing is a complex process regulated by various cell types and a plethora of mediators. While interactions between wounded skin and the hair follicles (HFs) could induce HF neogenesis or promote wound healing, it remains unknown whether the wound healing-associated signaling milieu can be manipulated to protect against alopecia, such as chemotherapy-induced alopecia (CIA). Utilizing a well-established neonatal rat model of CIA, we show here that skin wounding protects from alopecia caused by several clinically relevant chemotherapeutic regimens, and that protection is dependent on the time of wounding and hair cycle stage. Gene expression profiling unveiled a significant increase in interleukin-1 beta (IL-1β) mediated signaling by skin wounding. Subsequently, we showed that IL-1β is sufficient and indispensable for mediating the CIA-protective effect. Administration of IL-1β alone to unwounded rats exhibited local CIA protection while IL-1β neutralization abrogated CIA protection by wounding. Mechanistically, IL-1β retarded postnatal HF morphogenesis, making HFs at the wound sites or IL-1β treated areas damage-resistant while the rats developed total alopecia elsewhere. We conclude that wound healing switches the cutaneous cytokine milieu to an IL-1β-dominated state thus retarding HF growth progression and rendering the HFs resistant to chemotherapy agents. In the future, manipulation of HF progression through interfering with the IL-1β signaling milieu may provide therapeutic benefits to a variety of conditions, from prevention of CIA to inhibition of hair growth and treatment of hirsutism.

No / Knowledge of clinically and cost-effective wound management is an obvious requirement for surgeons, yet wound care education rarely features within the medical curriculum. As a result surgical trainees are often poorly placed to join in multidisciplinary wound management and may feel threatened when asked to manage wound complications. A vast range of dressing products exists yet robust evidence of the function and effectiveness of individual products is often lacking. An understanding of wound pathophysiology, a defined treatment goal and regular wound assessment combined with knowledge of basic wound dressing categories will provide guidance on product selection for different clinical situations and wound types.

No / Knowledge of clinically and cost-effective wound management is an obvious requirement for surgeons, yet wound care education rarely features within the medical curriculum. As a result surgical trainees are often poorly placed to join in multidisciplinary wound management and may feel threatened when asked to manage wound complications. A vast range of dressing products exists yet robust evidence of the function and effectiveness of individual products is often lacking. An understanding of wound pathophysiology, a defined treatment goal and regular wound assessment combined with knowledge of basic wound dressing categories will provide guidance on product selection for different clinical situations and wound types.

Yes / Mice represent the most commonly used species for preclinical in vivo research. While incisional and excisional acute murine wound models are both frequently employed, there is little agreement on which model is optimum. Moreover, current lack of standardization of wounding procedure, analysis time point(s), method of assessment, and the use of individual wounds vs. individual animals as replicates makes it difficult to compare across studies. Here we have profiled secondary intention healing of incisional and excisional wounds within the same animal, assessing multiple parameters to determine the optimal methodology for future studies. We report that histology provides the least variable assessment of healing. Furthermore, histology alone (not planimetry) is able to detect accelerated healing in a castrated mouse model. Perhaps most importantly, we find virtually no correlation between wounds within the same animal, suggesting that use of wound (not animal) biological replicates is perfectly acceptable. Overall, these findings should guide and refine future studies, increasing the likelihood of detecting novel phenotypes while reducing the numbers of animals required for experimentation.

The treatment of epidermal wounds, particularly chronic wounds, is one of the most ubiquitous medical challenges and has imposed a considerable financial burden on the global health care system. Several factors in epidermal wounds lead to severe medical conditions among which infection comprises a large number of mortalities. To tackle this issue, great efforts have been made in the last decades to incorporate antimicrobial agents into wound dressings in order to inhibit microorganism colonization. Additionally, various wound monitoring systems have been developed to detect and track infections using different indicators such as bacterial by-products. However, the integration of these infection sensors with wound dressings – most of which have benefited from electrochemical detectors – has been a major bottleneck due to the electrode failure in the wound environment and the need for electrical power supply. Other approaches have focused on the development of point-of-care devices that simplify the detection of infection. This study aims to address the aforementioned challenge by developing a multifunctional hydrogel-based wound dressing – made of alginate 1.5% (w/v) – for on-site infection monitoring via colourimetric and image processing methods. Taking advantage of wound acidity as an indicator of bacterial infection, the developed wound dressing was composed of an array of pH sensors, fabricated by 3-dimensional (3D) bioprinting. Brilliant Yellow and cabbage juice as two pH-responsive dyes were immobilized in the pH sensors to facilitate a wireless wound monitoring. In this system, Brilliant Yellow afforded a higher accuracy in image processing while cabbage juice provided a better visual observation of the wound condition. The functionality of the developed dressing in detecting bacterial infection was evaluated via an ex-vivo test on pig skin samples, infected by Pseudomonas aeruginosa, and the presence of bacteria was detected within 30 minutes after the placement of the dressings on the skin samples. Moreover, the inclusion of gentamicin-loaded components into the wound dressing facilitated the inhibition of bacterial growth, which was evaluated in vitro on the same strain of bacteria. In this experiment, 2 mg/ml of gentamicin in the hydrogel led to the eradication of P. aeruginosa. This incorporation of antibiotic delivery along with the simple colourimetric infection detection holds a great promise for managing acute and chronic wounds by inhibition of bacterial growth and monitoring infection in real-time without a need for dressing removal. / Graduate / 2018-08-16

Thesis (M.S.)--University of Akron, Dept. of Biomedical Engineering, 2006. / "May, 2006." Title from electronic thesis title page (viewed 12/03/2007) Advisor, S.I. Hariharan; Committee members, Daniel B. Sheffer, Narender P. Reddy; Department Chair, Daniel B. Sheffer; Dean of the College, George K. Haritos; Dean of the Graduate School, George R. Newkome. Includes bibliographical references.

A new design of dual-functional polyurea microcapsules was proposed for chronic wound dressings to provide both non-leaching infection control and sustained topical drug delivery functionalities. Quaternary ammonium functionalized polyurea microcapsules (MCQs) were synthesized under mild conditions through an interfacial crosslinking reaction between branched polyethylenimine (PEI) and 2,4-toluene diisocyanate (TDI) in a dimethylformamide/cyclohexane emulsion. An in-situ modification method was developed to endow non-leaching surface antimicrobial properties to MCQs via bonding antimicrobial surfactants to surface isocyanate residues on the polyurea shells. The resultant robust MCQs with both non-leaching antimicrobial properties and sustained drug releasing properties have potential applications in medical textiles, such as chronic wound dressings, for infection control and drug delivery.