Pre-clinical evaluation of liposomal gene transfer to improve dermal and epidermal regeneration

Functional characterization of the dimeric form of PDGF-derived fusion peptide fabricated based on theoretical arguments

A skin wound leads to the loss of skin integrity and the influx of pathogens into the tissue. Platelet-derived growth factors (PDGFs) are cytokines released from alpha granules during wound healing and interact with their cell surface receptors and activate signals involved in chemotaxis, growth, proliferation, and differentiation pathways. Due to the low stability of growth factors (GFs), a new peptide-derived PDGF-BB was designed, expressed in the Shuffle strain of E. coli, and purified by Ni-NTA agarose affinity column chromatography. The effect of fusion peptide was then evaluated on L929 fibroblast cells and animal models with skin lesions. In vitro, studies showed that the peptide led to an increase in the migration of fibroblast cells in the scratch assay. Its positive effect on wound healing was also observed in the skin-injured rats after 3, 7, and 12 days. A significant rise in neutrophils and granular tissue formation, re-epithelialization, angiogenesis, and collagen formation was exhibited on the third day of treatment when compared to the control group. The results showed that, despite reducing PDGF size, the fusion peptide was able to maintain at least some of the known functions attributed to full-length PDGF and showed positive results in wound healing.

Gene Therapy for Regenerative Medicine

The development of biological methods over the past decade has stimulated great interest in the possibility to regenerate human tissues. Advances in stem cell research, gene therapy, and tissue engineering have accelerated the technology in tissue and organ regeneration. However, despite significant progress in this area, there are still several technical issues that must be addressed, especially in the clinical use of gene therapy. The aims of gene therapy include utilising cells to produce a suitable protein, silencing over-producing proteins, and genetically modifying and repairing cell functions that may affect disease conditions. While most current gene therapy clinical trials are based on cell- and viral-mediated approaches, non-viral gene transfection agents are emerging as potentially safe and effective in the treatment of a wide variety of genetic and acquired diseases. Gene therapy based on viral vectors may induce pathogenicity and immunogenicity. Therefore, significant efforts are being invested in non-viral vectors to enhance their efficiency to a level comparable to the viral vector. Non-viral technologies consist of plasmid-based expression systems containing a gene encoding, a therapeutic protein, and synthetic gene delivery systems. One possible approach to enhance non-viral vector ability or to be an alternative to viral vectors would be to use tissue engineering technology for regenerative medicine therapy. This review provides a critical view of gene therapy with a major focus on the development of regenerative medicine technologies to control the in vivo location and function of administered genes.

Nanoparticles for Topical Application in the Treatment of Skin Dysfunctions-An Overview of Dermo-Cosmetic and Dermatological Products

Nanomaterials (NM) arouse interest in various fields of science and industry due to their composition-tunable properties and the ease of modification. They appear currently as components of many consumer products such as sunscreen, dressings, sports clothes, surface-cleaning agents, computer devices, paints, as well as pharmaceutical and cosmetics formulations. The use of NPs in products for topical applications improves the permeation/penetration of the bioactive compounds into deeper layers of the skin, providing a depot effect with sustained drug release and specific cellular and subcellular targeting. Nanocarriers provide advances in dermatology and systemic treatments. Examples are a non-invasive method of vaccination, advanced diagnostic techniques, and transdermal drug delivery. The mechanism of action of NPs, efficiency of skin penetration, and potential threat to human health are still open and not fully explained. This review gives a brief outline of the latest nanotechnology achievements in products used in topical applications to prevent and treat skin diseases. We highlighted aspects such as the penetration of NPs through the skin (influence of physical-chemical properties of NPs, the experimental models for skin penetration, methods applied to improve the penetration of NPs through the skin, and methods applied to investigate the skin penetration by NPs). The review summarizes various therapies using NPs to diagnose and treat skin diseases (melanoma, acne, alopecia, vitiligo, psoriasis) and anti-aging and UV-protectant nano-cosmetics.

Formulation-based approaches for dermal delivery of vaccines and therapeutic nucleic acids: Recent advances and future perspectives

A growing variety of biological macromolecules are in development for use as active ingredients in topical therapies and vaccines. Dermal delivery of biomacromolecules offers several advantages compared to other delivery methods, including improved targetability, reduced systemic toxicity, and decreased degradation of drugs. However, this route of delivery is hampered by the barrier function of the skin. Recently, a large body of research has been directed toward improving the delivery of macromolecules to the skin, ranging from nucleic acids (NAs) to antigens, using noninvasive means. In this review, we discuss the latest formulation-based efforts to deliver antigens and NAs for vaccination and treatment of skin diseases. We provide a perspective of their advantages, limitations, and potential for clinical translation. The delivery platforms discussed in this review may provide formulation scientists and clinicians with a better vision of the alternatives for dermal delivery of biomacromolecules, which may facilitate the development of new patient-friendly prophylactic and therapeutic medicines.

Stem Cells as a Target for the Delivery of Active Molecules to Skin by Topical Administration

Cutaneous stem cells, gained great attention in the field of regenerative medicine as a potential therapeutic target for the treatment of skin and hair disorders and various types of skin cancers. Cutaneous stem cells play a key role in several processes like the renovation of skin structures in the condition of homeostasis and after injuries, the hair follicle growth and the reconstruction and production of melanocytes. Thus, gaining effective access to skin stem cells for therapeutic interventions that often involve active molecules with non-favorable characteristics for skin absorption is a valuable achievement. The topical route with high patient compliance and several other benefits is gaining increasing importance in basic and applied research. However, the major obstacle for topical drug delivery is the effective barrier provided by skin against penetration of the vast majority of exogenous molecules. The research in this field is focusing more and more on new strategies to circumvent and pass this barrier effectively. In this article the existing approaches are discussed considering physical and chemical methods along with utilization of novel drug delivery systems to enhance penetration of drugs to the skin. In particular, attention has been paid to studies finalized to the delivery of molecules to cutaneous stem cells with the aim of transferring signals, modulating their metabolic program, inducing physiological modifications and stem cell gene therapy.

Basic concepts, current evidence, and future potential for gene therapy in managing cutaneous wounds

OBJECTIVE

Several studies have investigated the role of gene therapy in the healing process. The aim of this review is to explain the gene delivery systems in wound area.

RESULTS

Ninety-two studies were included and comprehensively overviewed. We described the importance of viral vectors such as adenoviruses, adeno-associated viruses, and retroviruses, and conventional non-viral vectors such as naked DNA injections, liposomes, gene gun, electroporation, and nanoparticles in achieving high-level expression of genes. Application of viral transfection, liposomal vectors, and electroporation were the main gene delivery systems. Genes encoding for growth factors or cytokines have been shown to result in a better wound closure in comparison to application of the synthetic growth factors. In addition, a combination of stem cell and gene therapy has been found an effective approach in regeneration of cutaneous wounds.

CONCLUSIONS

This article gives an overview of the methods and investigations applied on gene therapy in wound healing. However, clinical investigations need to be undertaken to gain a better understanding of gene delivery technologies and their roles in stimulating wound repair.

Re-epithelialization of adult skin wounds: Cellular mechanisms and therapeutic strategies

Cutaneous wound healing in adult mammals is a complex multi-step process involving overlapping stages of blood clot formation, inflammation, re-epithelialization, granulation tissue formation, neovascularization, and remodelling. Re-epithelialization describes the resurfacing of a wound with new epithelium. The cellular and molecular processes involved in the initiation, maintenance, and completion of epithelialization are essential for successful wound closure. A variety of modulators are involved, including growth factors, cytokines, matrix metalloproteinases, cellular receptors, and extracellular matrix components. Here, we focus on cellular mechanisms underlying keratinocyte migration and proliferation during epidermal closure. Inability to re-epithelialize is a clear indicator of chronic non-healing wounds, which fail to proceed through the normal phases of wound healing in an orderly and timely manner. This review summarizes the current knowledge regarding the management and treatment of acute and chronic wounds, with a focus on re-epithelialization, offering some insights into novel future therapies.

Wound coverage technologies in burn care: novel techniques

Improvements in burn wound care have vastly decreased morbidity and mortality in severely burned patients. Development of new therapeutic approaches to increase wound repair has the potential to reduce infection, graft rejection, and hypertrophic scarring. The incorporation of tissue-engineering techniques, along with the use of exogenous proteins, genes, or stem cells to enhance wound healing, heralds new treatment regimens based on the modification of already existing biological activity. Refinements to surgical techniques have enabled the creation of protocols for full facial transplantation. With new technologies and advances such as these, care of the severely burned will undergo massive changes over the next decade. This review centers on new developments that have recently shown great promise in the investigational arena.

The year in burns 2010

For 2010, roughly 1446 original burn research articles were published in scientific journals using the English language. This article reviews those with the most impact on burn treatment according to the Editor of one of the major journals (Burns) and his colleagues. As in previous reviews, articles were divided into the following topic areas: epidemiology, demographics of injury, wound characterisation and treatment, critical care, inhalation injury, infection, metabolism and nutrition, psychological considerations, pain and itching management, rehabilitation and long-term outcomes, and burn reconstruction. Each paper is considered very briefly, and the reader is referred to full manuscripts for details.