Bécaplermine gel (Regranex® gel)

Chitosan Particles Complexed with CA5-HIF-1α Plasmids Increase Angiogenesis and Improve Wound Healing

Wound therapies involving gene delivery to the skin have significant potential due to the advantage and ease of local treatment. However, choosing the appropriate vector to enable successful gene expression while also ensuring that the treatment's immediate material components are conducive to healing itself is critical. In this study, we utilized a particulate formulation of the polymer chitosan (chitosan particles, CPs) as a non-viral vector for the delivery of a plasmid encoding human CA5-HIF-1α, a degradation resistant form of HIF-1α, to enhance wound healing. We also compared the angiogenic potential of our treatment (HIF/CPs) to that of chitosan particles containing only the plasmid backbone (bb/CPs) and the chitosan particle vector alone (CPs). Our results indicate that chitosan particles exert angiogenic effects that are enhanced with the human CA5-HIF-1α-encoded plasmid. Moreover, HIF/CPs enhanced wound healing in diabetic db/db mice (p < 0.01), and healed tissue was found to contain a significantly increased number of blood vessels compared to bb/CPs (p < 0.01), CPs (p < 0.05) and no-treatment groups (p < 0.01). Thus, this study represents a method of gene delivery to the skin that utilizes an inherently pro-wound-healing polymer as a vector for plasmid DNA that has broad application for the expression of other therapeutic genes.

Stages of preadipocyte differentiation: biomarkers and pathways for extracellular structural remodeling

BACKGROUND

This study utilized bioinformatics to analyze the underlying biological mechanisms involved in adipogenic differentiation, synthesis of the extracellular matrix (ECM), and angiogenesis during preadipocyte differentiation in human Simpson-Golabi-Behmel syndrome at different time points and identify targets that can potentially improve fat graft survival.

RESULTS

We analyzed two expression profiles from the Gene Expression Omnibus and identified differentially expressed genes (DEGs) at six different time points after the initiation of preadipocyte differentiation. Related pathways were identified using Gene Ontology/Kyoto Encyclopedia of Genes and Genomes analyses and Gene Set Enrichment Analysis (GSEA). We further constructed a protein-protein interaction (PPI) network and its central genes. The results showed that upregulated DEGs were involved in cell differentiation, lipid metabolism, and other cellular activities, while downregulated DEGs were associated with angiogenesis and development, ECM tissue synthesis, and intercellular and intertissue adhesion. GSEA provided a more comprehensive basis, including participation in and positive regulation of key pathways of cell metabolic differentiation, such as the "peroxisome proliferator-activated receptor signaling pathway" and the "adenylate-activated protein kinase signaling pathway," a key pathway that negatively regulates pro-angiogenic development, ECM synthesis, and adhesion.

CONCLUSIONS

We identified the top 20 hub genes in the PPI network, including genes involved in cell differentiation, ECM synthesis, and angiogenesis development, providing potential targets to improve the long-term survival rate of fat grafts. Additionally, we identified drugs that may interact with these targets to potentially improve fat graft survival.

The emerging translational potential of GDF11 in chronic wound healing

Chronic skin wounds impose immense suffers and economic burdens. Current research mainly focuses on acute wound management which exhibits less effective in chronic wound healing. Growth differentiation factor 11 (GDF11) has profound effects on several important physiological processes related to chronic wound healing, such as inflammation, cell proliferation, migration, angiogenesis, and neurogenesis. This review summarizes recent advances in biology of chronic wounds and the potential role of GDF11 on wound healing with its regenerative effects, as well as the potential delivery methods of GDF11. The challenges and future perspectives of GDF11-based therapy for chronic wound care are also discussed.

The Translational Potential of this Article: This review summarized the significance of GDF11 in the modulation of inflammation, vascularization, cell proliferation, and remodeling, which are important physiological processes of chronic wound healing. The potential delivery methods of GDF11 in the management of chronic wound healing is also summarized. This review may provide potential therapeutic approaches based on GDF11 for chronic wound healing.

Engineering Bioactive Scaffolds for Skin Regeneration

Large skin wounds pose a major clinical challenge. Scarcity of donor site and postsurgical scarring contribute to the incomplete or partial loss of function and aesthetic concerns in skin wound patients. Currently, a wide variety of skin grafts are being applied in clinical settings. Scaffolds are used to overcome the issues related to the misaligned architecture of the repaired skin tissues. The current review summarizes the contribution of biomaterials to wound healing and skin regeneration and addresses the existing limitations in skin grafting. Then, the clinically approved biologic and synthetic skin substitutes are extensively reviewed. Next, the techniques for modification of skin grafts aiming for enhanced tissue regeneration are outlined, and a summary of different growth factor delivery systems using biomaterials is presented. Considering the significant progress in biomaterial science and manufacturing technologies, the idea of biomaterial-based skin grafts with the ability for scarless wound healing and reconstructing full skin organ is more achievable than ever.

Eliminating non-healing wounds: a review

Non-healing cutaneous wounds, including pressure, diabetic and venous ulcers, are wounds where the skin and underlying tissues die due to ischemia, infection, metabolic conditions, immunosuppression or radiation. Some can be eliminated with relatively straightforward techniques, although they may continue to grow in diameter and depth, becoming increasingly painful and never heal. Others respond more slowly or poorly to treatment, while others are recalcitrant to treatments. This review examines the etiology of non-healing wounds and different wound management treatments. In addition, it examines the efficacy of platelet-rich plasma in promoting wound healing and its potential mechanisms of action. It is concluded that platelet-rich plasma alone, but more effectively when combined with another technique(s), has the greatest potential for promoting complete wound healing. However, further studies are required to determine whether the efficacy of wound healing induced by each of these techniques is enhanced by applying the techniques simultaneously.

Antiangiogenic therapy in diabetic nephropathy: A double‑edged sword (Review)

Diabetes and the associated complications are becoming a serious global threat and an increasing burden to human health and the healthcare systems. Diabetic nephropathy (DN) is the primary cause of end-stage kidney disease. Abnormal angiogenesis is well established to be implicated in the morphology and pathophysiology of DN. Factors that promote or inhibit angiogenesis serve an important role in DN. In the present review, the current issues associated with the vascular disease in DN are highlighted, and the challenges in the development of treatments are discussed.

Wound Healing Potential of Chlorogenic Acid and Myricetin-3-O-β-Rhamnoside Isolated from Parrotia persica

Wound healing is a complex physiological process that is controlled by a well-orchestrated cascade of interdependent biochemical and cellular events, which has spurred the development of therapeutics that simultaneously target these active cellular constituents. We assessed the potential of Parrotia persica (Hamamelidaceae) in wound repair by analyzing the regenerative effects of its two main phenolic compounds, myricetin-3-O-β-rhamnoside and chlorogenic acid. To accomplish this, we performed phytochemical profiling and characterized the chemical structure of pure compounds isolated from P. persica, followed by an analysis of the biological effects of myricetin-3-O-β-rhamnoside and chlorogenic acid on three cell types, including keratinocytes, fibroblasts, and endothelial cells. Myricetin-3-O-β-rhamnoside and chlorogenic acid exhibited complementary pro-healing properties. The percentage of keratinocyte wound closure as measured by a scratch assay was four fold faster in the presence of 10 µg/mL chlorogenic acid, as compared to the negative control. On the other hand, myricetin-3-O-β-rhamnoside at 10 µg/mL was more effective in promoting fibroblast migration, demonstrating a two-fold higher rate of closure compared to the negative control group. Both compounds enhanced the capillary-like tube formation of endothelial cells in an in vitro angiogenesis assay. Our results altogether delineate the potential to synergistically accelerate the fibroblastic and remodelling phases of wound repair by administering appropriate amounts of myricetin-3-O-β-rhamnoside and chlorogenic acid.

Improving the ability to eliminate wounds and pressure ulcers

Pressure ulcers can be initiated by as little as 2 hours of constant pressure on the ski, that blocks blood circulation causing the skin and underlying tissues to die, leading to an open wound that never heals, but continues to grow in diameter and depth, and frequently jeopardizes patients' lives. Despite the application of many diverse techniques, pressure ulcers remain exceptionally difficult to heal because many ulcer elimination techniques have minimal effects, and although other techniques may appear to be effective, the evidence supporting their efficacy is weak. However, increasing evidence indicates that other techniques, such as the application of platelet-rich plasma, vacuum assisted closure, electrical stimulation, and hyperbaric oxygen therapy are effective and should be substituted for the older techniques. This review describes different standard and novel techniques that have been tested for eliminating pressure ulcers and discusses the relative efficacy of these techniques.

A comprehensive review of advanced biopolymeric wound healing systems

Wound healing is a complex and dynamic process that involves the mediation of many initiators effective during the healing process such as cytokines, macrophages and fibroblasts. In addition, the defence mechanism of the body undergoes a step-by-step but continuous process known as the wound healing cascade to ensure optimal healing. Thus, when designing a wound healing system or dressing, it is pivotal that key factors such as optimal gaseous exchange, a moist wound environment, prevention of microbial activity and absorption of exudates are considered. A variety of wound dressings are available, however, not all meet the specific requirements of an ideal wound healing system to consider every aspect within the wound healing cascade. Recent research has focussed on the development of smart polymeric materials. Combining biopolymers that are crucial for wound healing may provide opportunities to synthesise matrices that are inductive to cells and that stimulate and trigger target cell responses crucial to the wound healing process. This review therefore outlines the processes involved in skin regeneration, optimal management and care required for wound treatment. It also assimilates, explores and discusses wound healing drug-delivery systems and nanotechnologies utilised for enhanced wound healing applications.

Simple, rapid, high-purity preparation of recombinant human platelet-derived growth factor-BB

Recombinant human platelet-derived growth factor-BB (rhPDGF-BB) is used to treat full-thickness diabetic ulcers and is being investigated for use in other chronic ulcers, non-healing wounds, and periodontal defects. A simple, novel method for expression and purification of rhPDGF-BB from Escherichia coli is now described. This method produces the dimeric protein in high yield (10-12 mg/g wet cell mass) and with a purity >95%. rhPDGF-BB was exclusively found in inclusion bodies (IBs) representing approx. 30% of the total cell proteins. The IBs were extracted and the monomer purified by RP-HPLC. The purified rhPDGF-B monomer was then refolded using Tris buffer and subsequently dimerized to produce biologically active rhPDGF-BB. This product was composed of two polypeptide chains, each approx. 12 kDa. The final product exhibited specific activity in a fibroblast proliferation assay indistinguishable from that of the WHO reference standard.

Emerging drugs for diabetic foot ulcers

Diabetic foot ulceration results from factors extrinsic to the foot such as repeated trauma, ischaemia and infection, as well as intrinsic factors that lead to impairment of wound healing. Intrinsic factors are less well understood, but include deficiency of growth factors, changes in extracellular matrix components with excess proteases, reduced fibroblast activity, cellular abnormalities, deficiencies of angiogenesis, nitric oxide abnormalities and hyperglycaemia. The scientific rationale of therapy is to correct both the external factors that cause diabetic foot ulcers and the internal factors that lead to impairment of wound healing. Current research is leading to new therapies that can be divided into the following classes: growth factors, skin substitutes, extracellular matrix proteins, stem cell therapy, gene therapy, protease inhibitors, angiogenesis stimulants, nitric oxide-releasing agents, adenosine agonists, immunostimulants, vasoactive compounds and granulating agents. These therapies should be considered when existing treatments to correct extrinsic factors have failed to heal ulceration in the diabetic foot.

Accelerated Healing of Excisional Skin Wounds by PL 14736 in Alloxan-Hyperglycemic Rats1

PL 14736 is a synthetic peptide, originally isolated from human gastric juice, that has anti-inflammatory and tissue-protective actions in experimental models of gastrointestinal inflammation. To investigate its possible benefit in poorly healing skin wounds, the effects of the topical application of PL 14736 in a gel formulation have been studied on full-thickness excisional wounds in rats, either healthy or made hyperglycemic by alloxan (175 mg/kg s.c.) 5 days previously. The effects of becaplermin gel (platelet-derived growth factor, PDGF-BB, Regranex, a standard therapy for diabetic foot ulcers, were investigated for comparison. Healing was evaluated for up to 7 days after wounding, using digital planimetry analysis, macroscopic scoring and histology. While healing was too rapid in healthy rats to observe enhancement by either treatment, in the hyperglycemic rats which exhibited delayed healing, PL 14736 (10-1,000 microg/wound) produced a dose-dependent acceleration of wound healing (determined by macroscopic scoring) equivalent at the highest doses to that observed with becaplermin. The beneficial effect on healing was associated with increased deposition of organized granulation tissue by day 7 for both PL 14736 and becaplermin, as determined histologically. PL 14736 tended to have a greater effect than becaplermin on the formation of granulation tissue containing mature collagen. Wound contraction, as measured by planimetry, was not significantly affected. In conclusion, topical PL 14736 produces a dose-dependent acceleration of deficient skin wound healing in hyperglycemic rats by facilitating granulation tissue formation, similar to the response seen with topical becaplermin, the standard therapy for diabetic skin wounds. PL 14736 may represent an alternative therapy for delayed wound healing, such as that seen with diabetic foot ulcers, without the proliferative concerns or immunogenicity associated with growth factors.