Gene delivery of PDGF for wound healing therapy

Topical Drug Delivery in the Treatment of Skin Wounds and Ocular Trauma Using the Platform Wound Device

Topical treatment of injuries such as skin wounds and ocular trauma is the favored route of administration. Local drug delivery systems can be applied directly to the injured area, and their properties for releasing therapeutics can be tailored. Topical treatment also reduces the risk of adverse systemic effects while providing very high therapeutic concentrations at the target site. This review article highlights the Platform Wound Device (PWD) (Applied Tissue Technologies LLC, Hingham, MA, USA) for topical drug delivery in the treatment of skin wounds and eye injuries. The PWD is a unique, single-component, impermeable, polyurethane dressing that can be applied immediately after injury to provide a protective dressing and a tool for precise topical delivery of drugs such as analgesics and antibiotics. The use of the PWD as a topical drug delivery platform has been extensively validated in the treatment of skin and eye injuries. The purpose of this article is to summarize the findings from these preclinical and clinical studies.

Materials Science and Design Principles of Growth Factor Delivery Systems in Tissue Engineering and Regenerative Medicine

Growth factors (GFs) are signaling molecules that direct cell development by providing biochemical cues for stem cell proliferation, migration, and differentiation. GFs play a key role in tissue regeneration, but one major limitation of GF-based therapies is dosage-related adverse effects. Additionally, the clinical applications and efficacy of GFs are significantly affected by the efficiency of delivery systems and other pharmacokinetic factors. Hence, it is crucial to design delivery systems that provide optimal activity, stability, and tunable delivery for GFs. Understanding the physicochemical properties of the GFs and the biomaterials utilized for the development of biomimetic GF delivery systems is critical for GF-based regeneration. Many different delivery systems have been developed to achieve tunable delivery kinetics for single or multiple GFs. The identification of ideal biomaterials with tunable properties for spatiotemporal delivery of GFs is still challenging. This review characterizes the types, properties, and functions of GFs, the materials science of widely used biomaterials, and various GF loading strategies to comprehensively summarize the current delivery systems for tunable spatiotemporal delivery of GFs aimed for tissue regeneration applications. This review concludes by discussing fundamental design principles for GF delivery vehicles based on the interactive physicochemical properties of the proteins and biomaterials.

Biomaterials and Nanotherapeutics for Enhancing Skin Wound Healing

Wound healing is an intricate process that requires complex coordination between many cell types and an appropriate extracellular microenvironment. Chronic wounds often suffer from high protease activity, persistent infection, excess inflammation, and hypoxia. While there has been intense investigation to find new methods to improve cutaneous wound care, the management of chronic wounds, burns, and skin wound infection remain challenging clinical problems. Ideally, advanced wound dressings can provide enhanced healing and bridge the gaps in the healing processes that prevent chronic wounds from healing. These technologies have great potential for improving outcomes in patients with poorly healing wounds but face significant barriers in addressing the heterogeneity and clinical complexity of chronic or severe wounds. Active wound dressings aim to enhance the natural healing process and work to counter many aspects that plague poorly healing wounds, including excessive inflammation, ischemia, scarring, and wound infection. This review paper discusses recent advances in the development of biomaterials and nanoparticle therapeutics to enhance wound healing. In particular, this review focuses on the novel cutaneous wound treatments that have undergone significant preclinical development or are currently used in clinical practice.

Combined gene and stem cell therapy for cutaneous wound healing

In current medical practice, wound therapy remains a clinical challenge and much effort has been focused on the development of novel therapeutic approaches for wound treatment. Gene therapy, initially developed for treatment of congenital defects, represents a promising option for enhancing wound repair. In order to accelerate wound closure, genes encoding for growth factors or cytokines have shown the most potential. The majority of gene delivery systems are based on viral transfection, naked DNA application, high pressure injection, and liposomal vectors. Besides advances stemming from breakthroughs in recombinant growth factors and bioengineered skin, there has been a significant increase in the understanding of stem cell biology in the field of cutaneous wound healing. A variety of sources, such as bone marrow, umbilical cord blood, adipose tissue and skin/hair follicles, have been utilized to isolate stem cells and to modulate the healing response of acute and chronic wounds. Recent data have demonstrated the feasibility of autologous adult stem cell therapy in cutaneous repair and regeneration. Very recently, stem cell based skin engineering in conjunction with gene recombination, in which the stem cells act as both the seed cells and the vehicle for gene delivery to the wound site, represents the most attractive field for generating a regenerative strategy for wound therapy. The aim of this article is to discuss the use and the potential of these novel technologies in order to improve wound healing capacities.

Assessment and nutritional aspects of wound healing

PURPOSE OF REVIEW

The aim of this study is to review the physiopathology and the nutritional aspects of wound healing.

RECENT FINDINGS

Wound healing consists of a perfect and coordinated cascade of events that result in tissue reconstitution. The healing process is common to all wounds, independent of the agent that has caused it. It is divided didactically into three phases: inflammation, proliferation, and remodeling or maturation. Collagen is the most abundant protein in the human body and is also the main component of the wound matrix. It is organized in a thick and dynamic net, resulting from constant collagen deposition and reabsorption. Wound scar is the result of the interaction between collagen synthesis, degradation, and remodeling. There are several ways to evaluate wound healing: tensiometry, collagen morphometry, immunohistochemistry, and, more recently, the dosage of growth factors. Malnutrition adversely affects wound healing. On the contrary, the healing process can be stimulated by preoperative feeding and by certain nutrients such as glutamine, arginine, butyrate, and antioxidants.

SUMMARY

Wound healing is a complex process that started to be fully understood only in recent years. Recent research has been directed to act in the nutrition modulation of the healing process.

Cicatrização de feridas

INTRODUÇÃO: A cicatrização de feridas consiste em perfeita e coordenada cascata de eventos que culminam com a reconstituição tecidual. O processo cicatricial é comum a todas as feridas, independe do agente que a causou. O processo de cicatrização é dividido didaticamente em três fases: inflamatória, proliferação ou granulação e remodelamento ou maturação. O colágeno é a proteína mais abundante no corpo humano e também é o principal componente da matriz extracelular dos tecidos. Estrutura-se numa rede densa e dinâmica resultante da sua constante deposição e reabsorção. O tecido cicatricial é resultado da interação entre sua síntese, fixação e degradação. Existem várias maneiras de avaliar a cicatrização das feridas. Os métodos mais utilizados atualmente são a tensiometria, a densitometria e morfometria do colágeno, a imunoistoquímica e, mais recentemente, a dosagem de fatores de crescimento. MÉTODOS: Foram revisadas todas as dissertações de mestrado e teses de doutorado realizadas na linha de pesquisa "Cicatrização de órgãos e tecidos" do programa de Pós-Graduação em Clínica Cirúrgica da Universidade Federal do Paraná. Foi realizada, também, revisão atualizada da literatura internacional no Pubmed e nacional. CONCLUSÃO: A cicatrização é um processo complexo, que começou a ser entendido em maior amplitude nos últimos anos. Recentes pesquisas têm sido direcionadas para atuar na modulação da cicatrização a nível molecular, na tentativa de evitar completamente cicatrizes patológicas.

Cutaneous gene therapy

Possibilities of using the skin for somatic gene therapy have been investigated for more than 20 years. Strategies have included both direct gene transfer into the skin and indirect gene transfer utilizing cultured cells as an intermediate step for gene manipulation. Viral as well as nonviral vectors have been used, and both gene addition and gene editing have been performed. Although cutaneous gene therapy has now begun translating into clinical medicine (as seen by the first clinical gene therapy project of an inherited skin disorder) further developments are still required.