A Novel Comprehensive Therapeutic Approach to the Challenges of Chronic Wounds: A Brief Review and Clinical Experience Report

Following the clinical perspective and concept that a healthy body will not develop chronic wounds, the central approach for the treatment described here is based on an understanding of how the body transforms the wound microenvironment from a non-healing to a healing state. As part of a comprehensive treatment regimen that includes OCM™ (complete matrix), wound preparation, and skin protectant formulations, the OCM contains components for complete wound healing by attending to the individual needs required to promote the closure of each unique chronic wound. During application of the comprehensive treatment regimen in independent investigator-led trials, the total wound percentage average reduction over the first 4 weeks of treatment was 60% across multiple wound types; median time to total wound closure was 6.9 weeks. Safety testing of the OCM formulation shows no potential allergenicity, no potential sensitization, and no known product-related adverse events. Clinical trials evaluating the OCM formulation as part of the comprehensive treatment regimen of multiple wound types are underway. Results of clinical trials and real-world experiences will expand current knowledge of the wound-healing potential of this novel product.

Extracellular vesicles modulate key signalling pathways in refractory wound healing

Chronic wounds are wounds that cannot heal properly due to various factors, such as underlying diseases, infection or reinjury, and improper healing of skin wounds and ulcers can cause a serious economic burden. Numerous studies have shown that extracellular vesicles (EVs) derived from stem/progenitor cells promote wound healing, reduce scar formation and have significant advantages over traditional treatment methods. EVs are membranous particles that carry various bioactive molecules from their cellular origins, such as cytokines, nucleic acids, enzymes, lipids and proteins. EVs can mediate cell-to-cell communication and modulate various physiological processes, such as cell differentiation, angiogenesis, immune response and tissue remodelling. In this review, we summarize the recent advances in EV-based wound healing, focusing on the signalling pathways that are regulated by EVs and their cargos. We discuss how EVs derived from different types of stem/progenitor cells can promote wound healing and reduce scar formation by modulating the Wnt/β-catenin, phosphoinositide 3-kinase/protein kinase B/mammalian target of rapamycin, vascular endothelial growth factor, transforming growth factor β and JAK-STAT pathways. Moreover, we also highlight the challenges and opportunities for engineering or modifying EVs to enhance their efficacy and specificity for wound healing.

[Clinical effects of autologous platelet rich plasma gel combined with vacuum sealing drainage techno-logy in repairing refractory wounds]

Objective: To investigate the clinical effects of autologous platelet rich plasma (PRP) gel in combination with vacuum sealing drainage (VSD) technology in repairing refractory wounds. Methods: From March 2011 to January 2015, 44 patients with refractory wounds meeting the inclusion criteria were recruited into VSD alone group, who were admitted to the Department of Burns and Plastic Surgery of the Yidu Central Hospital of Weifang and received intermittent VSD treatment. From February 2015 to September 2019, 43 patients with refractory wounds meeting the inclusion criteria were recruited into PRP+ VSD group, who were admitted to the same unit as above-mentioned and received PRP combined with intermittent VSD treatment. The retrospective cohort study was conducted. There were 24 males and 20 females with age of (37.5±2.2) years in VSD alone group, and there were 25 males and 18 females with age of (37.0±2.5) years in PRP+ VSD group. The wound exudate of patients in the two groups before and 7 and 14 d after the first treatment were collected for bacterial culture, and the positive rate of bacterial culture was calculated. The wound healing of patients in the two groups was observed on 7, 14, and 21 d after the first treatment, and the wound healing rate was calculated. The complete wound healing time of patients in the two groups was recorded. The degree of wound pain of patients in the two groups was evaluated by the Visual Analog Scale (VAS) before and 14 d after the first treatment. The scar hyperplasia of patients in the two groups was evaluated by the Vancouver Scar Scale (VSS) in 1 and 2 months after the wound healed completely. The occurrence of adverse reactions of patients in the two groups during the whole period of treatment was observed and the incidence of adverse reactions was calculated. Data were statistically analyzed with analysis of variance for repeated measurement, chi-square test, paired t test, and Bonferroni correction. Results: The positive rates of bacterial culture in wound exudate of patients in PRP+ VSD on 7 and 14 d after the first treatment were 37.2% (16/43) and 11.6% (5/43), which were significantly lower than 56.8% (25/44) and 29.5% (13/44) in VSD alone group, χ(2)=4.212, 4.255, P<0.05. The wound healing rates of patients in PRP+ VSD group on 7 and 14, and 21 d after the first treatment were respectively (58±14)%, (70±13)%, (89±12)%, which were significantly higher than (41±11)%, (60±11)%, (74±12)% in VSD alone group, t=6.323, 3.820, 5.751, P<0.01. The complete wound healing time of patients in PRP+ VSD group was (30±6) d, which was significantly shorter than (61±8) d in VSD alone group, t=20.890, P<0.05. The VAS score of patients in PRP+ VSD group was significantly lower than that in VSD alone group on 14 d after the first treatment (t=13.904, P<0.01). The VSS score of patients in PRP+ VSD group was significantly lower than that in VSD alone group in 1 and 2 months after the wound healed completely (t=3.307, 3.637, P<0.01). The incidence of adverse reactions of patients in PRP+ VSD group during the whole period of treatment was 7.0% (3/43), which was significantly lower than 22.7% (10/44) in VSD alone group, χ(2)=4.245, P<0.05. Conclusions: Autologous PRP gel combined with VSD technology in repairing refractory wounds not only has good bacteriostatic effect, but also can increase wound healing rate, shorten wound healing time, alleviate wound pain, reduce scar hyperplasia, with less adverse reaction, which is worthy of promotion.

In situ depot comprising phase-change materials that can sustainably release a gasotransmitter H2S to treat diabetic wounds

Patients with diabetes mellitus are prone to develop refractory wounds. They exhibit reduced synthesis and levels of circulating hydrogen sulfide (H₂S), which is an ephemeral gaseous molecule. Physiologically, H₂S is an endogenous gasotransmitter with multiple biological functions. An emulsion method is utilized to prepare a microparticle system that comprises phase-change materials with a nearly constant temperature of phase transitions to encapsulate sodium hydrosulfide (NaHS), a highly water-labile H₂S donor. An emulsion technique that can minimize the loss of water-labile active compounds during emulsification must be developed. The as-prepared microparticles (NaHS@MPs) provide an in situ depot for the sustained release of exogenous H₂S under physiological conditions. The sustained release of H₂S promotes several cell behaviors, including epidermal/endothelial cell proliferation and migration, as well as angiogenesis, by extending the activation of cellular ERK1/2 and p38, accelerating the healing of full-thickness wounds in diabetic mice. These experimental results reveal the strong potential of NaHS@MPs for the sustained release of H₂S for the treatment of diabetic wounds.

[Effects of transient exposure to high glucose on biological behaviors of human dermal microvascular endothelial cells]

Objective: To observe the effects of transient exposure to high glucose on biological behaviors of human dermal microvascular endothelial cells cultured in vitro. Methods: The dividing method and treatment of cells for the detection of all indexes in this study were as follows. Human dermal microvascular endothelial cells of the 4th passage were divided into 3 groups according to the random number table, with 12 wells in each group. Cells in control group (C) were cultured with complete culture solution containing 5 mmol/L D-glucose for 7 d. Cells in transient high glucose group (THG) were cultured with complete culture solution containing 30 mmol/L D-glucose for 2 d and complete culture solution containing 5 mmol/L D-glucose for 5 d. Cells in prolonged high glucose group (PHG) were cultured with complete culture solution containing 30 mmol/L D-glucose for 7 d. (1) The cell morphology in groups C and PHG on culture day 7 and that in group THG on culture day 2 and 7 was observed by inverted optical microscope. (2) On culture day 0, 2, 4, and 7, cell proliferation rate was determined by cell viability analyzing counter. (3) After culture day 2, the scratch experiment was performed, and the cells were further cultured. At post scratch hour (PSH) 0, 24, 48, 72, 96, and 120, the scratch area was measured, and the cell migration rates of the latter 5 time points were calculated. (4) On culture day 0, 2, 4, and 7, the cell apoptosis rate was determined by cell analyzer. (5) Cells were seeded into Matrigel to culture for 24 h after culture day 7. The formation of vessel-like structure was observed by inverted optical microscope. The length and number of branch point of vessel-like structure were calculated. (6) On culture day 2, 4, and 7, mRNA expression of vascularization-related gene tissue inhibitor of matrix metalloproteinase-3 (TIMP-3) was determined with real-time fluorescent quantitative reverse transcription polymerase chain reaction. Data were processed with analysis of variance of factorial design, analysis of variance for repeated measurement, one-way analysis of variance, and LSD test. Results: (1) Cells in group C exhibited ovary shape in cobble stone order on culture day 7. Cells in group THG exhibited long ovary shape and lost cobble stone order on culture day 2 and kept the same changes on culture day 7. Cells in group PHG exhibited long ovary shape and lost cobble stone order on culture day 7. (2) On culture day 0, there was no significant difference in cell proliferation rate among the 3 groups (F=0.23, P>0.05). On culture day 2, cell proliferation rates in groups THG and PHG were similar (P>0.05), which were significantly lower than the cell proliferation rate in group C (with P values below 0.01). On culture day 4 and 7, the cell proliferation rates in groups THG and C were similar (with P values above 0.05), which were significantly higher than those in group PHG (with P values below 0.01). (3) At PSH 24-120, the cell migration rates in groups THG and PHG were similar (with P values above 0.05), which were significantly lower than those in group C (with P values below 0.01). (4) On culture day 0, there was no statistically significant difference in cell apoptosis rate among the 3 groups (F=0.78, P>0.05). On culture day 2, cell apoptosis rates in groups THG and PHG were similar (P>0.05), which were significantly higher than the cell apoptosis rate in group C (with P values below 0.01). On culture day 4 and 7, the cell apoptosis rates in groups THG and C were similar (with P values above 0.05), which were significantly lower than those in group PHG (with P values below 0.01). (5) The length of vessel-like structure of cells in group THG was (1.84±0.10)×10(5) μm, close to (1.82±0.11)×10(5) μm in group PHG (P>0.05), both significantly shorter than (2.75±0.23)×10(5) μm in group C (with P values below 0.01). The numbers of branch point of vessel-like structure of cells in groups THG and PHG were 43±5 and 46±8 respectively, which were close to each other (P>0.05) and both significantly less than 103±21 in group C (with P values below 0.01). (6) On culture day 2, 4, and 7, mRNA expressions of TIMP-3 of cells in groups THG and PHG were similar (with P values above 0.05), which were significantly lower than those in group C (with P values below 0.05). Conclusions: Transient exposure to high glucose can cause metabolic memory of morphology, migration, and angiogenesis in human dermal microvascular endothelial cells cultured in vitro, resulting in sustained changes in biological behaviors. The mechanism may be related to the changes of vascularization-related genes.