Physiological processes of inflammation and edema initiated by sustained mechanical loading in subcutaneous tissues: A scoping review

Bacterial nanocellulose/calcium alginate hydrogel for the treatment of burns

PURPOSE

Bacterial cellulose (BC) has shown high capacity for the treatment of wounds and burns, providing a moisty environment. Calcium alginate can be associated with BC to create gels that aid in wound debridement and contribute to appropriate wound healing. This study is aimed at characterizing and evaluating the use of bacterial cellulose/alginate gel in skin burns in rats.

METHODS

Cellulose and cellulose/alginate gels were compared regarding the capacity of liquid absorption, moisture, viscosity, and potential cytotoxicity. The 2nd degree burns were produced using an aluminum metal plate (2.0cm) at 120ºC for 20s on the back of rats. The animals were divided into non-treated, CMC(Carboxymethylcellulose), Cellulose(CMC with bacterial cellulose), and Cellulose/alginate(CMC with bacterial cellulose and alginate). The animals received topical treatment 3 times/week. Biochemical (MPO, NAG and oxidative stress), histomorphometry and immunohistochemical assays (IL-1β IL-10 and VEGF) were conducted on the 14th, 21st, 28th, and 35th days.

RESULTS

Cellulose/Alginate gel showed higher absorption capacity and viscosity compared to Cellulose gel, with no cytotoxic effects. Cellulose/alginate presented lower MPO values, a higher percentage of IL-10, with greater and balanced oxidative stress profile.

CONCLUSIONS

The use of cellulose/alginate gel reduced neutrophils and macrophage activation and showed greater anti-inflammatory response, which can contribute to healing chronic wounds and burns.

Testing the effectiveness of a polymeric membrane dressing in modulating the inflammation of intact, non-injured, mechanically irritated skin

We investigated the inflammatory (IL-1 alpha) and thermal (infrared thermography) reactions of healthy sacral skin to sustained, irritating mechanical loading. We further acquired digital photographs of the irritated skin (at the visible light domain) to assess whether infrared imaging is advantageous. For clinical context, the skin status was monitored under a polymeric membrane dressing known to modulate the inflammatory skin response. The IL-1 alpha and infrared thermography measurements were consistent in representing the skin status after 40 min of continuous irritation. Infrared thermography overpowered conventional digital photography as a contactless optical method for image processing inputs, by revealing skin irritation trends that were undetectable through digital photography in the visual light, not even with the aid of advanced image processing. The polymeric membrane dressings were shown to offer prophylactic benefits over simple polyurethane foam in the aspects of inflammation reduction and microclimate management. We also concluded that infrared thermography is a feasible method for monitoring the skin health status and the risk for pressure ulcers, as it avoids the complexity of biological marker studies and empowers visual skin assessments or digital photography of skin, both of which were shown to be insufficient for detecting the inflammatory skin status.

The healing effect of topical tea tree oil on pressure ulcers in a rat model

Objective: The effects of topical tea tree oil (TTO) on the healing of pressure ulcers (PUs) in an animal model was evaluated. Method: To induce PUs, ischaemia-reperfusion cycles were performed by the external application of magnetic plates, with an ischaemic period of eight hours and a reperfusion period of 16 hours. Male and female Wistar rats were divided into three equally sized groups (n=20): one group received topical glycerin twice daily, another group received topical 10% (volume/volume (v/v)) TTO in glycerin twice daily; and the remaining group was untreated. The animals were assessed after one, four, seven and 14 cycles of ischaemia-reperfusion by thermal camera imaging, and then euthanised and sampled to investigate the degree of inflammation, collagen synthesis and apoptosis in the PUs. Results: Although topical glycerin alone suppressed local inflammation and apoptosis, this suppressive effect was accentuated at all timepoints by the application of topical TTO + glycerin. Similarly, an increase in collagen synthesis was observed in the glycerin group and this was accentuated by TTO at all timepoints. Parallel to the histological findings, the local temperature had decreased significantly on days 4 and 7 for both treatment groups (glycerin and TTO+glycerin). Conclusion: In this study, treatment with 10% (v/v) TTO in glycerin effectively suppressed skin inflammation and apoptosis, while it increased collagen synthesis during PU formation.

The healing effect of topical tea tree oil on pressure ulcers in a rat model

Objective: The effects of topical tea tree oil (TTO) on the healing of pressure ulcers (PUs) in an animal model was evaluated. Method: To induce PUs, ischaemia-reperfusion cycles were performed by the external application of magnetic plates, with an ischaemic period of eight hours and a reperfusion period of 16 hours. Male and female Wistar rats were divided into three equally sized groups (n=20): one group received topical glycerin twice daily, another group received topical 10% (volume/volume (v/v)) TTO in glycerin twice daily; and the remaining group was untreated. The animals were assessed after one, four, seven and 14 cycles of ischaemia-reperfusion by thermal camera imaging, and then euthanised and sampled to investigate the degree of inflammation, collagen synthesis and apoptosis in the PUs. Results: Although topical glycerin alone suppressed local inflammation and apoptosis, this suppressive effect was accentuated at all timepoints by the application of topical TTO + glycerin. Similarly, an increase in collagen synthesis was observed in the glycerin group and this was accentuated by TTO at all timepoints. Parallel to the histological findings, the local temperature had decreased significantly on days 4 and 7 for both treatment groups (glycerin and TTO+glycerin). Conclusion: In this study, treatment with 10% (v/v) TTO in glycerin effectively suppressed skin inflammation and apoptosis, while it increased collagen synthesis during PU formation.

The effect of head of bed elevation on sacral and heel subepidermal moisture in healthy adults: A randomised crossover study

BACKGROUND

Subepidermal moisture (SEM) changes may detect early tissue injury and enhance pressure injury risk assessments. However, little is known how modifiable factors, like head of bed elevation (HOBE), affect SEM.

AIM

This study investigated the influence of HOBE on sacral and heel SEM, using the Provizio ® SEM Scanner.

METHOD

A 2 × 2 randomised crossover study compared the effects of 30-min of 30⁰ versus 60⁰ HOBE on sacral and heel SEM in healthy adults.

RESULTS

48 participants were randomly allocated to 30⁰ or 60⁰ HOBE and crossed over after a 60-min washout period. The mean age was 40.6 years (SD = 18.3). The study found the sacral and heel SEM values were not statistically different at 30⁰ versus 60⁰ HOBE. No clinically relevant association between SEM and characteristics of age, sex, body mass index and skin type were found. Baseline sacral and heel SEM values recovered after a 60-min washout period. Notably, half of the initial baseline measures suggested pressure injury risk.

CONCLUSION

The HOBE may not influence SEM at the sacrum and heels, in healthy adults after 30 min of loading. Standard operating procedures for measuring SEM for pressure injury risk assessment require a stronger body of evidence in varied populations and timeframes before this technology is widely adopted.

TRIAL REGISTRATION

Australian and New Zealand Clinical Trials Registry ACTRN12622001456741.

In Vitro and In Vivo Characterization Methods for Evaluation of Modern Wound Dressings

Chronic wound management represents a major challenge in the healthcare sector owing to its delayed wound-healing process progression and huge financial burden. In this regard, wound dressings provide an appropriate platform for facilitating wound healing for several decades. However, adherent traditional wound dressings do not provide effective wound healing for highly exudating chronic wounds and need the development of newer and innovative wound dressings to facilitate accelerated wound healing. In addition, these dressings need frequent changing, resulting in more pain and discomfort. In order to overcome these issues, a wide range of affordable and innovative modern wound dressings have been developed and explored recently to accelerate and improve the wound healing process. However, a comprehensive understanding of various in vitro and in vivo characterization methods being utilized for the evaluation of different modern wound dressings is lacking. In this context, an overview of modern dressings and their complete in vitro and in vivo characterization methods for wound healing assessment is provided in this review. Herein, various emerging modern wound dressings with advantages and challenges have also been reviewed. Furthermore, different in vitro wound healing assays and in vivo wound models being utilized for the evaluation of wound healing progression and wound healing rate using wound dressings are discussed in detail. Finally, a summary of modern wound dressings with challenges and the future outlook is highlighted.

Projected Augmented Reality (P-AR) for Enhancing Nursing Education About Pressure Injury: A Pilot Evaluation Study

PURPOSE

To describe results of a study evaluating a Projected Augmented Reality (P-AR) system for its potential to enhance nursing education about pressure injuries.

DESIGN

Pilot evaluation survey.

SUBJECTS AND SETTING

The sample comprised nursing students and faculty at a school of nursing in a large, Midwestern public university. A total of 32 participants, which included 27 students (30% BSN, 44% MN, and 26% DNP students; 81% female) and 5 faculty members (80% female) participated.

METHODS

The P-AR system was prototyped using commercial-off-the-shelf components and software algorithms, applied to pressure injury nursing education content. After interaction with the P-AR system, participants completed a survey evaluating the following features of the P-AR system for potential: engagement, effectiveness, usefulness, user-friendliness, and realism, and users' overall impression and satisfaction with system features. Evaluation statements used a 5-level Likert-scale; open-ended questions about what was liked, disliked, or anything else offered opportunity for comments.

RESULTS

Student and faculty median evaluation scores were 5 (strongly agree or very satisfied) and 4 (agree or satisfied) for nearly all evaluation and satisfaction statements. Students' satisfaction with "realism" received a median score of 3 (neutral). The P-AR system was refined to include realistic still and animated images.

CONCLUSION

The P-AR system, an innovative technology using 3-dimensional dynamic images, was applied to nursing education content about pressure injury and was evaluated as having potential to enhance pressure injury teaching and learning. Education about complex processes of pressure injury development and management may benefit from using cutting-edge simulation technologies such as P-AR.

The performance of gelling fibre wound dressings under clinically relevant robotic laboratory tests

The effectiveness of wound dressing performance in exudate management is commonly gauged in simple, non‐realistic laboratory setups, typically, where dressing specimens are submersed in vessels containing aqueous solutions, rather than by means of clinically relevant test configurations. Specifically, two key fluid–structure interaction concepts: sorptivity—the ability of wound dressings to transfer exudate, including viscous fluids, away from the wound bed by capillary action and durability—the capacity of dressings to maintain their structural integrity over time and particularly, at removal events, have not been properly addressed in existing test protocols. The present article reviews our recent published research concerning the development of clinically relevant testing methods for wound dressings, focussing on the clinical relevance of the tests as well as on the standardisation and automation of laboratory measurements of dressing performance. A second objective of this work was to compile the experimental results characterising the performance of gelling fibre dressings, which were acquired using advanced testing methods, to demonstrate differences across products that apparently belong to the same “gelling fibre” family but differ remarkably in materials, structure and composition and, thereby, in performance.

A regenerative approach to the pharmacological management of hard-to-heal wounds

A wound is considered hard-to-heal when, despite the appropriate clinical analysis and intervention, the wound area reduces by less than a third at four weeks and complete healing fails to occur within 12 weeks. The most prevalent hard-to-heal wounds are associated with underlying metabolic diseases or vascular insufficiency and include arterial, venous, pressure and diabetic foot ulcers. Their common features include an abnormal immune response and extended inflammatory phase, a subdued proliferation phase due to cellular insufficiencies and finally an almost non-existent remodeling phase. Advances in wound care technology, tested in both pre-clinical models and clinical trials, have paved the way for improved treatment options, focused on regeneration. These interventions have been shown to limit the extent of ongoing inflammatory damage, decrease bacterial load, promote angiogenesis and deposition of granulation tissue, and stimulate keratinocyte migration thereby promoting re-epithelialization in these wounds. The current review discusses these hard-to-heal wounds in the context of their underlying pathology and potential of advanced treatment options, which if applied promptly as a standard of care, could reduce morbidity, promote quality of life, and alleviate the burden on a strained health system.

Outcomes of present-on-admission pressure injuries at discharge and potential prognostic factors: A historical cohort study in China

BACKGROUND

The prevalence of present-on-admission pressure injuries (POA-PIs) is much higher than hospital-acquired pressure injuries (HAPIs). But scant attention has been paid to POA-PIs, especially the healing rate and potential prognostic factors.

OBJECTIVE

To describe the characteristics of POA-PIs at admission and the outcomes of POA-PIs at discharge, and to explore potential prognostic factors of POA-PIs wound healing.

METHODS

This study analyzed electronic health records (EHRs) for 838 POA-PIs among 586 patients from a Chinese tertiary hospital in 2018. The outcomes of POA-PIs were identified into four categories by comparing POA-PIs' wound area and exudation amount scores at admission and discharge: deteriorating, stable, improving, and healed. The generalized estimating equation (GEE) was carried out to screen the prognostic factors of POA-PIs wound healing.

RESULTS

Among this population, 66.38% of the patients were male, 44.03% patients had a Braden Score less than 12 and the median of the Charlson comorbidity index was 5. The most common location of POA-PI wounds was the sacrum and the most common stage of them was Stage II. Nearly half of wounds (45.78%) were larger than 15 cm², 26.61% were deeper than 0.5 cm, and 61.81% of the wounds were painful. When the patients were discharged, 29.71% wounds were healed, 36.16% were in improving status, 25.78% kept stable, and 8.35% wounds were in deteriorating status. Wound depth was the only independent prognostic factor for POA-PIs wound healing.

CONCLUSIONS

The healing rate of POA-PIs is quite low, and the only independent prognostic factor of POA-PIs was wound depth.

Our contemporary understanding of the aetiology of pressure ulcers/pressure injuries

In 2019, the third and updated edition of the Clinical Practice Guideline (CPG) on Prevention and Treatment of Pressure Ulcers/Injuries has been published. In addition to this most up‐to‐date evidence‐based guidance for clinicians, related topics such as pressure ulcers (PUs)/pressure injuries (PIs) aetiology, classification, and future research needs were considered by the teams of experts. To elaborate on these topics, this is the third paper of a series of the CPG articles, which summarises the latest understanding of the aetiology of PUs/PIs with a special focus on the effects of soft tissue deformation. Sustained deformations of soft tissues cause initial cell death and tissue damage that ultimately may result in the formation of PUs/PIs. High tissue deformations result in cell damage on a microscopic level within just a few minutes, although it may take hours of sustained loading for the damage to become clinically visible. Superficial skin damage seems to be primarily caused by excessive shear strain/stress exposures, deeper PUs/PIs predominantly result from high pressures in combination with shear at the surface over bony prominences, or under stiff medical devices. Therefore, primary PU/PI prevention should aim for minimising deformations by either reducing the peak strain/stress values in tissues or decreasing the exposure time.

Role of microRNAs in Pressure Ulcer Immune Response, Pathogenesis, and Treatment

Pressure ulcers are preventable, yet highly prevalent, chronic wounds that have significant patient morbidity and high healthcare costs. Like other chronic wounds, they are characterized by impaired wound healing due to dysregulated immune processes. This review will highlight key biochemical pathways in the pathogenesis of pressure injury and how this signaling leads to impaired wound healing. This review is the first to comprehensively describe the current literature on microRNA (miRNA, miR) regulation of pressure ulcer pathophysiology.

The sorptivity and durability of gelling fibre dressings tested in a simulated sacral pressure ulcer system

Wound‐dressing performances are affected by exudate viscosity, resistance to flow because of gravity, and bodyweight loads, the level of which is related to the body position. Here, we focussed on two dressing properties: (a) Sorptivity—the ability of dressings to transfer exudate away from the wound bed by capillary action—and (b) Durability—the capacity of dressings to maintain their integrity over time and during their removal. Both properties are critically important for avoiding further tissue damage but require the development of new laboratory tests for their measurement. A computer‐controlled phantom of an exuding sacral pressure ulcer has therefore been developed and used to compare the performances of Exufiber (Mölnlycke Health Care) vs an alternative market‐leading dressing. Sorptivity was determined using weight tests, and durability was measured through tensile tests of the used dressings. For a supine configuration, the Exufiber dressing demonstrated ~three times higher sorptivity and better durability, withstanding ~five times greater strain energy than the other product before failure occurred. This work paves the way for quantitative, standardised testing of dressings in all aspects of exudate management. The reported tests are further suitable for testing dressing combinations or how dressings interact with negative pressure wound therapy.

Novel Functions of the Septin Cytoskeleton: Shaping Up Tissue Inflammation and Fibrosis

Chronic inflammatory diseases cause profound alterations in tissue homeostasis, including unchecked activation of immune and nonimmune cells leading to disease complications such as aberrant tissue repair and fibrosis. Current anti-inflammatory therapies are often insufficient in preventing or reversing these complications. Remodeling of the intracellular cytoskeleton is critical for cell activation in inflamed and fibrotic tissues; however, the cytoskeleton has not been adequately explored as a therapeutic target in inflammation. Septins are GTP-binding proteins that self-assemble into higher order cytoskeletal structures. The septin cytoskeleton exhibits a number of critical cellular functions, including regulation of cell shape and polarity, cytokinesis, cell migration, vesicle trafficking, and receptor signaling. Surprisingly, little is known about the role of the septin cytoskeleton in inflammation. This article reviews emerging evidence implicating different septins in the regulation of host-pathogen interactions, immune cell functions, and tissue fibrosis. Targeting of the septin cytoskeleton as a potential future therapeutic intervention in human inflammatory and fibrotic diseases is also discussed.