The angiogenic peptide vascular endothelial growth factor-basic fibroblast growth factor signaling is up-regulated in a rat pressure ulcer model

Advance in topical biomaterials and mechanisms for the intervention of pressure injury

Pressure injuries (PIs) are localized tissue damage resulting from prolonged compression or shear forces on the skin or underlying tissue, or both. Different stages of PIs share common features include intense oxidative stress, abnormal inflammatory response, cell death, and subdued tissue remodeling. Despite various clinical interventions, stage 1 or stage 2 PIs are hard to monitor for the changes of skin or identify from other disease, whereas stage 3 or stage 4 PIs are challenging to heal, painful, expensive to manage, and have a negative impact on quality of life. Here, we review the underlying pathogenesis and the current advances of biochemicals in PIs. We first discuss the crucial events involved in the pathogenesis of PIs and key biochemical pathways lead to wound delay. Then, we examine the recent progress of biomaterials-assisted wound prevention and healing and their prospects.

An appraisal of vascular endothelial growth factor (VEGF): the dynamic molecule of wound healing and its current clinical applications

Angiogenesis is a critical step of wound healing, and its failure leads to chronic wounds. The idea of restoring blood flow to the damaged tissues by promoting neo-angiogenesis is lucrative and has been researched extensively. Vascular endothelial growth factor (VEGF), a key dynamic molecule of angiogenesis has been investigated for its functions. In this review, we aim to appraise its biology, the comprehensive role of this dynamic molecule in the wound healing process, and how this knowledge has been translated in clinical application in various types of wounds. Although, most laboratory research on the use of VEGF is promising, its clinical applications have not met great expectations. We discuss various lacunae that might exist in making its clinical application unsuccessful for commercial use, and provide insight to the foundation for future research.

Predicting the Development of Surgery-Related Pressure Injury Using a Machine Learning Algorithm Model

BACKGROUND

Surgery-related pressure injury (SRPI) is a serious problem in patients who undergo cardiovascular surgery. Identifying patients at a high risk of SRPI is important for clinicians to recognize and prevent it expeditiously. Machine learning (ML) has been widely used in the field of healthcare and is well suited to predictive analysis.

PURPOSE

The aim of this study was to develop an ML-based predictive model for SRPI in patients undergoing cardiovascular surgery.

METHODS

This secondary analysis of data was based on a single-center, prospective cohort analysis of 149 patients who underwent cardiovascular surgery. Data were collected from a 1,000-bed university-affiliated hospital. We developed the ML model using the XGBoost algorithm for SRPI prediction in patients undergoing cardiovascular surgery based on major potential risk factors. Model performance was tested using a receiver operating characteristic curve and the C-index.

RESULTS

Of the sample of 149 patients, SRPI developed in 37, an incidence rate of 24.8%. The five most important predictors included duration of surgery, patient weight, duration of the cardiopulmonary bypass procedure, patient age, and disease category. The ML model had an area under the receiver operating characteristic curve of 0.806, which indicates that the ML model has a moderate prediction value for SRPI.

CONCLUSIONS

Applying ML to clinical data may be a reliable approach to the assessment of the risk of SRPI in patients undergoing cardiovascular surgical procedures. Future studies may deploy the ML model in the clinic and focus on applying targeted interventions for SRPI and related diseases.

Chronological changes in rat heel skin following depressurization of pressure ulcer-like dermal lesions

In our previous study, we proposed an animal model in which pressure ulcer-like dermal lesions can be produced by denervation of the sciatic nerve and application of a pressure load to rat heel skin. In the present study, we divided these animals into non-treated and pressure loading groups, and initiated hindlimb unloading (depressurization) by tail suspension at 1, 3, 5, 7, and 14 days after inflicting lesions (1-14d pressurization groups). Chronological changes in heel lesions were examined morphologically in all treatment groups after 1, 3, 7, 14, 28, and 40 days. Open dermal lesions were formed by 14 days in the loading group and numerous macrophages were present. In the 14d pressurization group, numerous macrophages were still distributed in and around lesions and Vascular endothelial cell growth factor (VEGF) expression was strongly detected by 3 days, but a thin germinal layer began to appear and CD68-positive macrophages and VEGF immunoreactions decreased gradually by 7 days later. By 14 days after depressurization, the germinal layer was repaired, and macrophages and immunoreactions of VEGF were similar to those of non-treated skin. These chronological changes were similar to those in human pressure ulcers, but from 5d after depressurization, different chronological changes were observed. Specifically, epidermis was thickened and macrophages were hardly detected at 5 days in the loading group, but the epidermis disappeared by 1 day in the 5d pressurization group. Subsequently, numerous macrophages aggregated and VEGF expression was increased by 3 days, and the remaining healing process was similar to that in the 14d pressurization group. Even when unloading was performed during the early stages (5d pressurization group), the epidermis disappeared and macrophages were then distributed before repair of the lesion was observed. These results suggest that earlier migration of macrophages to skin lesions might be associated with rapid wound healing.

Exploring the effect of epigenetic modifiers on developing insulin-secreting cells

Diabetes is a worldwide health problem with increasing incidence. The current management modalities did not succeed to decrease comorbidities. This study aimed at enhancing the regenerative solution for diabetes by improving the differentiation of mesenchymal stromal cells (MSC) into glucose-sensitive, insulin-secreting cells through an epigenetic modification approach. A 3-day treatment protocol with the epigenetic modifiers, either decitabine (5-aza-2'-deoxycytidine; Aza); a DNA methylation inhibitor or Vorinostat (suberoylanilide hydroxamic acid; SAHA); a histone deacetylase inhibitor was added to two different human stem cell lines. The cells followed a multi-step differentiation protocol that provided the critical triggers in a temporal approach. Aza-pretreated group showed higher intracellular expression of insulin and the transcription factor 'PDX-1'. The cells responded to the high glucose challenge by secreting insulin in the media, as shown by ELISA. Gene expression showed induction of the genes for insulin, the glucose transporter 2, glucokinase, as well as the transcription factors MafA and NKX6.1. Although SAHA showed upregulation of insulin secretion, in comparison to control, the cells could not respond to the high glucose challenge. Interestingly, Aza-treated cells showed a significant decrease in the global DNA methylation level at the end of the culture. In conclusion, this additional step with Aza could enhance the response of MSC to the classical differentiation protocol for insulin-secreting cells and may help in establishing a regenerative solution for patients with diabetes.

Mesenchymal stem cells derived from human iPS cells via mesoderm and neuroepithelium have different features and therapeutic potentials

Mesenchymal stem cells (MSCs) isolated from adult human tissues are capable of proliferating in vitro and maintaining their multipotency, making them attractive cell sources for regenerative medicine. However, the availability and capability of self-renewal under current preparation regimes are limited. Induced pluripotent stem cells (iPSCs) now offer an alternative, similar cell source to MSCs. Herein, we established new methods for differentiating hiPSCs into MSCs via mesoderm-like and neuroepithelium-like cells. Both derived MSC populations exhibited self-renewal and multipotency, as well as therapeutic potential in mouse models of skin wounds, pressure ulcers, and osteoarthritis. Interestingly, the therapeutic effects differ between the two types of MSCs in the disease models, suggesting that the therapeutic effect depends on the cell origin. Our results provide valuable basic insights for the clinical application of such cells.

A novel model of human skin pressure ulcers in mice

INTRODUCTION

Pressure ulcers are a prevalent health problem in today's society. The shortage of suitable animal models limits our understanding and our ability to develop new therapies. This study aims to report on the development of a novel and reproducible human skin pressure ulcer model in mice.

MATERIAL AND METHODS

Male non-obese, diabetic, severe combined immunodeficiency mice (n = 22) were engrafted with human skin. A full-thickness skin graft was placed onto 4×3 cm wounds created on the dorsal skin of the mice. Two groups with permanent grafts were studied after 60 days. The control group (n = 6) was focused on the process of engraftment. Evaluations were conducted with photographic assessment, histological analysis and fluorescence in situ hybridization (FISH) techniques. The pressure ulcer group (n = 12) was created using a compression device. A pressure of 150 mmHg for 8 h, with a total of three cycles of compression-release was exerted. Evaluations were conducted with photographic assessment and histological analysis.

RESULTS

Skin grafts in the control group took successfully, as shown by visual assessment, FISH techniques and histological analysis. Pressure ulcers in the second group showed full-thickness skin loss with damage and necrosis of all the epidermal and dermal layers (ulcer stage III) in all cases. Complete repair occurred after 40 days.

CONCLUSIONS

An inexpensive, reproducible human skin pressure ulcer model has been developed. This novel model will facilitate the development of new clinically relevant therapeutic strategies that can be tested directly on human skin.

Perioperative corticosteroids administration as a risk factor for pressure ulcers in cardiovascular surgical patients: a retrospective study

The aim of this study was to investigate the relationship between perioperative corticosteroids administration and the incidence of pressure ulcers (PUs) in cardiovascular surgical patients. A retrospective analysis was performed on data from consecutive patients who had cardiac surgery in 2012. Univariate and multivariate logistic regression analyses were performed to evaluate the relationship between perioperative corticosteroid administration and the incidence of surgery-related PU (SRPU). A total of 286 cardiac surgery patients were included in this study; of these, 47 patients developed 57 SRPUs, an incidence of 16·4% [95% confidence interval (CI): 12·3-21·2%). The SRPU incidence was significantly higher in corticosteroid-administered group compared with groups not receiving corticosteroids (43·8% versus 14·8%, Pearson's χ(2)  = 9·209, P = 0·002). The crude odds ratio (OR) was 4·472 (95% CI: 1·576-12·694). After performing multivariate logistic regression analysis, the adjusted OR was 2·808 (95% CI: 1·062-11·769). This result showed that perioperative corticosteroid administration was an independent risk factor for PUs in cardiovascular surgical patients. Therefore, it is recommended that in order to prevent PU perioperative corticosteroids should be administered with caution to cardiovascular surgical patients.