Growth factors and extracellular matrix biosynthesis

Optimization and evaluation of ciprofloxacin-loaded collagen/chitosan scaffolds for skin tissue engineering

A novel ciprofloxacin-loaded collagen-chitosan scaffold was developed for the treatment of wound using freeze drying method. The average pore size and porosity of developed scaffold was found to be around 125 µm and 91 ± 0.56%. Moreover, swelling, degradation and mechanical tests profile supported the suitability of scaffold for wound healing process. The scaffold has high degree of hemocompatibility towards the blood and promotes the growth, migration and proliferation of fibroblast. The developed scaffold exhibits antibacterial properties and was found to be efficient against the Gram-negative (E.coli) and Gram-positive (Staphylococcus aureus) bacteria hence can be used for wound healing applications. In vivo study demonstrated that the scaffold not only escalated the tissue regeneration time but also accelerated the wound healing process compared to control. The histological studies revealed better granulation, vascularization, and remodeling of extracellular matrix along with regeneration of epidermal and dermal layer of skin. Overall, the obtained results suggested that the developed skin tissue constructs possess the enormous potential for tissue regeneration and might be a suitable biomaterial for skin tissue engineering applications.

Pressure ulcer following circumferential head dressing

PURPOSE

To report four patients with forehead pressure ulcer (PU) following encircling head dressing and review the literature.

METHODS

Uneventful endoscopic forehead lift procedure was performed with moderate skin elevation in three patients. Left upper eyelid crease incision was made to remove the sub-brow dermoid cyst uneventfully in one patient. All procedures were performed under general anesthesia. Mixed topical antibiotic and steroid ointments were placed on the incision sites before putting the encircling forehead dressing (using gauze and elastic bandage). The dressing was then removed on the first postoperative examination.

RESULTS

Forehead and eyebrow PUs were observed on the first follow-up visit (16-72 h) after removing the dressing. Patients were otherwise healthy. They did not have significant pain or burning postoperatively. Management included pressure release, wound debridement, daily dressing, topical antibiotic and steroid, and silicone-based anti-scar cream. None had infected ulcer and all except one ended up with atrophic scar in the last follow-up (2-14 months). External pressure and shearing forces were assumed to be the main causative factors, even though reperfusion injury could contribute in the development of PU.

CONCLUSION

Encircling head dressing can cause PU and result in scar formation in healthy immunocompetent patients. If there is a low risk of postoperative hematoma, encircling dressing should be avoided. Early loosening of the dressing and frequent examination of the skin are the best preventive and diagnostic measures. Treatment includes pressure removal, daily debridement, and topical medications.

Managing surgical wound care: review of Leukomed Control dressings

Optimal management of surgical wounds is an important part of postoperative recovery. The aim of postoperative wound care is to facilitate rapid wound closure, while preventing complications and promoting minimal disturbance, to achieve the best functional and aesthetic results. Health professionals should seek to optimise the process of acute wound healing, observe progress, and prevent wound complications. Dressings that permit extended wear time, and are transparent and so allow early recognition without the need for unnecessary changes, have the potential to minimise the effect on patients and the wider health economy. This article reviews recommendations for surgical wound care, and introduces the recently launched Leukomed Control dressing that is entirely transparent and allows greater flexibility, breathability, and visualisation of the wound.

Hyaluronic acid: evaluation as a potential delivery vehicle for vitronectin:growth factor complexes in wound healing applications

We have previously reported that novel vitronectin:growth factor (VN:GF) complexes significantly increase re-epithelialization in a porcine deep dermal partial-thickness burn model. However, the potential exists to further enhance the healing response through combination with an appropriate delivery vehicle which facilitates sustained local release and reduced doses of VN:GF complexes. Hyaluronic acid (HA), an abundant constituent of the interstitium, is known to function as a reservoir for growth factors and other bioactive species. The physicochemical properties of HA confer it with an ability to sustain elevated pericellular concentrations of these species. This has been proposed to arise via HA prolonging interactions of the bioactive species with cell surface receptors and/or protecting them from degradation. In view of this, the potential of HA to facilitate the topical delivery of VN:GF complexes was evaluated. Two-dimensional (2D) monolayer cell cultures and 3D de-epidermised dermis (DED) human skin equivalent (HSE) models were used to test skin cell responses to HA and VN:GF complexes. Our 2D studies revealed that VN:GF complexes and HA stimulate the proliferation of human fibroblasts but not keratinocytes. Experiments in our 3D DED-HSE models showed that VN:GF complexes, both alone and in conjunction with HA, led to enhanced development of both the proliferative and differentiating layers in the DED-HSE models. However, there was no significant difference between the thicknesses of the epidermis treated with VN:GF complexes alone and VN:GF complexes together with HA. While the addition of HA did not enhance all the cellular responses to VN:GF complexes examined, it was not inhibitory, and may confer other advantages related to enhanced absorption and transport that could be beneficial in delivery of the VN:GF complexes to wounds.

Understanding physiology of wound healing and how dressings help

One of the most fascinating features of the human body is its ability to repair damaged tissue. When the skin is injured a complex process occurs. The natural healing process can be divided into four distinct stages: inflammatory, granulation, epithelization and maturation. This process can take up to 2 years. Brunner and Suddarth (1992) classified wound healing into three stages: primary; secondary; and tertiary. Many factors affect how long a wound will take to heal, e.g. concurrent illnesses, nutritional status and the dressing used. A holistic approach to wound care is the key, and if all the factors are not addressed then wound healing will not prevail.

The use of growth factors in clinical practice

The first in a two-part article reviewing the current and potential role of growth factors