Split-thickness skin autografts (AGs) are the standard surgical treatment for severe burn injuries. However, the treatment of patients with substantial skin loss is limited by the availability of ...donor sites for skin harvesting. As an alternative to skin autografts, our research group developed autologous self-assembled skin substitutes (SASSs), allowing the replacement of both dermis and epidermis in a single surgical procedure. The aim of the study was to assess the clinical outcome of the SASSs as a permanent coverage for full-thickness burn wounds. Patients were recruited through the Health Canada's Special Access Program. SASSs were grafted on debrided full-thickness wounds according to similar protocols used for AGs. The graft-take and the persistence of the SASS epithelium over time were evaluated. 14 patients received surgical care with SASSs. The mean percentage of the SASS graft-take was 98 % (standard deviation = 5) at 5 to 7 d after surgery. SASS integrity persisted over time (average follow-up time: 3.2 years), without noticeable deficiency in epidermal regeneration. Assessment of scar quality (skin elasticity, erythema, thickness) was performed on a subset of patients. Non-homogeneous pigmentation was noticed in several patients. These results indicated that the SASS allowed the successful coverage of full-thickness burns given its high graft-take, aesthetic outcome equivalent to autografting and the promotion of long-term tissue regeneration. When skin donor sites are in short supply, SASSs could be a valuable alternative to treat patients with full-thickness burns covering more than 50 % of their total body surface area.
A major challenge during the engineering of voluminous bone tissues is to maintain cell viability in the central regions of the construct. In vitro prevascularization of bone substitutes relying on ...endothelial cell bioprinting has the potential to resolve this issue and to replicate the native bone microvasculature. Laser-assisted bioprinting (LAB) commonly uses biological layers of hydrogel, called 'biopapers', to support patterns of printed cells and constitute the basic units of the construct. The self-assembly approach of tissue engineering allows the production of biomimetic cell-derived bone extracellular matrix including living cells. We hypothesized that self-assembled osseous sheets can serve as living biopapers to support the LAB of human endothelial cells and thus guide tubule-like structure formation. Human umbilical vein endothelial cells were bioprinted on the surface of the biopapers following a predefined pattern of lines. The osseous biopapers showed relevant matrix mineralization and pro-angiogenic hallmarks. Our results revealed that formation of tubule-like structures was favored when the cellular orientation within the biopaper was parallel to the printed lines. Altogether, we validated that human osseous cell sheets can be used as biopapers for LAB, allowing the production of human prevascularized cell-based osseous constructs that can be relevant for autologous bone repair applications.
The invasive properties of cancer cells depend on their intrinsic motile potential and on their ability to breach the endothelial barrier. In the present work, we investigated the mechanisms by which ...adhesion of colon cancer cells to E-selectin expressed by endothelial cells regulates the barrier function of these cells and modulates transmigration of cancer cells. We found that the stimulation of E-selectin by activating antibodies or the adhesion of HT-29 cells results in an increase in the activity of extracellular signal-regulated kinase (ERK) and p38 mitogen-activated protein kinases. In turn, the activation of p38 and ERK enhances transendothelial permeability and migration of HT-29 cells. We also obtained evidence suggesting that p38-mediated increase in transendothelial migration of cancer cells depends on a myosin light chain phosphorylation-mediated formation of stress fibres. On the other hand, the activation of ERK by E-selectin modulates the opening of interendothelial spaces by initiating the activation of Src kinase activities and the dissociation of the VE-cadherin/beta-catenin complex. We conclude that activation of E-selectin by adhering cancer cells is an important process that regulates the extravasation of colon cancer cells by initiating p38- and ERK-dependent mechanisms that both contribute to regulate the integrity of the endothelial layer.
Summary
Background
Ultraviolet radiation (UVR) is responsible for keratinocyte cancers through the induction of mutagenic cyclobutane pyrimidine dimers (CPDs). Many factors influence CPD repair in ...epidermal keratinocytes, and a better understanding of those factors might lead to prevention strategies against skin cancer.
Objectives
To evaluate the impact of dermal components on epidermal CPD repair efficiency and to investigate potential factors responsible for the dermal–epidermal crosstalk modulating UVR‐induced DNA damage repair in keratinocytes.
Methods
A model of self‐assembled tissue‐engineered skin containing human primary keratinocytes and fibroblasts was used in this study.
Results
We showed that CPD repair in keratinocytes is positively influenced by the presence of a dermis. We investigated the secretome and found that the cytokine CXCL5 is virtually absent from the culture medium of reconstructed skin, compared with media from fibroblasts and keratinocytes alone. By modulating CXCL5 levels in culture media of keratinocytes, we have shown that CXCL5 is an inhibitor of CPD repair.
Conclusions
This work outlines the impact of the secreted dermal components on epidermal UVR‐induced DNA damage repair and sheds light on a novel role of CXCL5 in CPD repair.
What is already known about this topic?
Repair of ultraviolet (UV)‐induced DNA damage is important in the prevention of skin cancer.
The three‐dimensional environment of the skin promotes efficient epidermal repair of cyclobutane pyrimidine dimers.
What does this study add?
Using tissue‐engineered skin models, we show that the dermis positively influences UV‐induced DNA repair in the epidermis.
Secreted molecules rather than extracellular components of the dermis influence DNA repair in the epidermis.
CXCL5 is an inhibitor of UV‐induced DNA repair in keratinocytes
What is the translational message?
Ultraviolet radiation causes mutagenic damage to epidermal cells, which, if not repaired efficiently, can lead to skin cancers.
We have shown that the dermis–epidermis interaction leads to a strong reduction of CXCL5, a repair inhibitor, which increases repair efficiency in the epidermis.
By its action on CXCL5, the dermis increases repair efficiency of mutagenic damage in the epidermis and would thus have a protective effect against ultraviolet‐induced skin cancer.
Linked Comment: Cadet. Br J Dermatol 2021; 184:9–10.
Consumption of single-use medical devices has increased considerably, contributing to the excessive wastage produced during surgical procedures. The present study aimed to describe a methodology to ...assess the transition from single-use blades (SUB) to reusable laryngoscope blades (RUB) and to assess the ecological and economic impact of the switch.
The ecological analysis was based on the life cycle assessment method. Based on 30 operating rooms in a single tertiary university hospital, the economic analysis compared the usual SUB supplier with four RUB suppliers considering different costs: blade purchasing and depreciation, reprocessing, logistics and waste management.
In 2021, 17,200 intubations were performed requiring about 147 RUBs. Switching from SUB to RUB led to an annual saving of 26.5 tons of CO2eq (global warming impact), equivalent to 120 000 km by car. It avoids the extraction of 6.6 tons Oileq (petroleum) and 579 kg of copper (mineral resources) per year. This action also leads to a land occupation reduction of 626 m2 per year and water savings of 221.6 m3 per year. The average cost per intubation varies from 3.16 3.15–3.16 for SUB to 2.81 2.77–2.85 for RUB, representing an average saving of 0.35 per intubation leading to 5783.50 annual gain 5074.00–6192.00. RUB are preferable from 3 and 86 uses from an ecological and economic viewpoint, respectively.
In a model of 17,200 intubations /year, switching SUD to RUB would save 26.5 tons of CO2eq and 6.6 tons of Oileq with 5783.50 annual gain. RUBs are ecologically and cost-effective after 3 and 86 uses, respectively.
For patients with amyotrophic lateral sclerosis (ALS), the primary therapeutic goal is to minimize morbidity. Non-invasive ventilation improves survival. We aim to assess whether Magnetic Resonance ...Imaging (MRI) of the cervical spinal cord predicts the progression of respiratory disorders in ALS. Brain and spinal MRI was repeatedly performed in the SOD1
mouse model, in 40 patients and in healthy controls. Atrophy, iron overload, white matter diffusivity and neuronal loss were assessed. In Superoxide Dismutase-1 (SOD1) mice, iron accumulation appeared in the cervical spinal cord at symptom onset but disappeared with disease progression (after the onset of atrophy). In ALS patients, the volumes of the motor cortex and the medulla oblongata were already abnormally low at the time of diagnosis. Baseline diffusivity in the internal capsule was predictive of functional handicap. The decrease in cervical spinal cord volume from diagnosis to 3 months was predictive of the change in slow vital capacity at 12 months. MRI revealed marked abnormalities at the time of ALS diagnosis. Early atrophy of the cervical spinal cord may predict the progression of respiratory disorders, and so may be of value in patient care and as a primary endpoint in pilot neuroprotection studies.
In this paper, the use of the reassignment method, first applied by Kodera, Gendrin, and de Villedary (1976) to the spectrogram, is generalized to any bilinear time-frequency or time-scale ...distribution. This method creates a modified version of a representation by moving its values away from where they are computed, so as to produce a better localization of the signal components. We first propose a new formulation of this method, followed by a thorough theoretical study of its characteristics. Its practical use for a large variety of known time-frequency and time-scale distributions is then addressed. Finally, some experimental results are reported to demonstrate the performance of this method.< >
Skin substitutes and wound healing Auger, F A; Lacroix, D; Germain, L
Skin pharmacology and physiology,
01/2009, Letnik:
22, Številka:
2
Journal Article
Recenzirano
Medical science has vastly improved on the means and methods available for the treatment of wounds in the clinic. The production and use of various types of skin substitutes has led to dramatic ...improvements in the odds of survival for severely burned patients, but they have also shown promise for many other applications, including cases involving chronic wounds that are not life threatening. Nowadays, more than 20 products are commercially available, more are undergoing clinical trials and a large number of new models are being investigated in various research laboratories worldwide. Many of the current products do not contain any living cells and vary in their capacity to harness the innate capacity of the body to heal itself. Others include living cells, of allogeneic or autologous origin, and are often referred to as 'cellular therapy' or 'tissue-engineered' products. Modifications and improvements are currently investigated that aim at improving the healing potential of those products through the use of recombinant growth factors and additional features such as microvascularization. Fundamental research into wound healing and scar-free regeneration raises the hope that we will eventually be able to restore almost completely the appearance and function of skin after the healing of wounds.
In the current context of climate change, actions must be taken to improve the hospital's ecological footprint, particularly in the operating room, which is a major consumer of medical devices.
This ...prospective pilot study assessed the ecological and economic impacts of sustainable actions targeting medical devices designed by a multidisciplinary working group and implemented in the 24 operating rooms of a University Hospital over one year. The ecological analysis was based on the life cycle assessment method and categorized in seven impacts. The economic impact was assessed by a micro-costing analysis and divided in four main expense items: human and material resources, logistics, and waste management.
In total, 13 actions were implemented with the aim of reducing waste volume, improving waste sorting, and increasing eco-responsible purchases. In one year, these 13 actions allowed avoiding the emission of 203 tons eq CO2. The environmental and human toxicity benefits were 707.8 and 156.2 tons of 1.4 dichlorobenzene, respectively. Concerning non-renewable resources, these actions avoided the extraction of 9 tons of oil (petroleum) and 610 kg of copper per year. These actions led to a land occupation reduction of 1071.3 m2year and to water saving of 552 m3. From the economic side, the implementation of these actions brought a gain of €3747.9 for the first year and of €5188.2 for the following years.
The integration of sustainable measures in operating rooms leads to important ecological benefits and also generating savings. This more eco-responsible approach should be considered in all healthcare establishments that generate a significant annual volume of waste.
•In the current context of climate change, actions must be taken to improve the hospital's ecological footprint, particularly in the Operating Room (OR).•The implementation of targeted actions on the medical device makes it possible to considerably reduce CO2 emissions and water consumption while saving natural resources.•The integration of sustainable measures in OR also generates savings for the Hospital.
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