Growth factors and cytokines: Emphasis on their role in wound healing and atherosclerosis

Production and Characterization of Electrospun Chitosan, Nanochitosan and Hyaluronic Acid Membranes for Skin Wound Healing

The development of new wound dressings made from biomaterials, which offer a better cost-benefit ratio and accelerate the healing process, is increasing nowadays. Various biopolymers can be electrospun to form functional membranes for wound healing. Therefore, in this study, chitosan and nanochitosan membranes with or without hyaluronic acid were prepared using the electrospinning technique, characterized and evaluated in the healing of skin wounds in rats. Chitosan and nanochitosan solutions, with or without hyaluronic acid, were prepared at concentrations of 1%-4% using PEO (polyethylene oxide) and subjected to the electrospinning process to obtain membranes characterized by scanning electron microscopy (SEM), mechanical tests, and antimicrobial activity. The healing effect of the membranes was evaluated by monitoring the area of the lesions, contraction of the wounds, histologic analysis, and induction of pro-inflammatory cytokine (IL-1 α and TNF-α) production in rats. The nanochitosan and nanochitosan membranes with hyaluronic acid achieved greater fiber diameter and uniformity, resistance, elasticity, and thermal stability, in addition to good adhesion to the wound bed and permeation capacity. Despite not presenting antimicrobial activity in vitro, they contributed to the production of pro-inflammatory interleukins in the animals tested, provided physical protection, reduced the wound area more markedly until the seventh day of the evaluation, with an acceleration of the healing process and especially when functionalized with hyaluronic acid. These results indicate that the membranes may be promising for accelerating the healing process of chronic wounds in humans.

Bulbine natalensis and Bulbine frutescens promote cutaneous wound healing

ETHNOPHARMACOLOGICAL RELEVANCE

The gel from the leaves of Bulbine natalensis (BN) and Bulbine frutescens (BF) is commonly used as a traditional medicine in South Africa for the treatment of skin wounds and burns. Treatment with both leaf gel extracts has previously been demonstrated to increase tensile strength and protein and DNA content in pig dermal wounds. This study examined the effect of the leaf gel extracts in vivo on histology of wound healing in pigs to elucidate the mechanism of increased tensile strength.

MATERIALS AND METHODS

Mirror imaged wounds on the dorsum of 12 post weaning female pigs were treated with either BN or BF, biopsied at days 2, 4, 7, 10 and 16 post-wounding and fixed. Sections of wound tissue were then stained with haematoxylin and eosin and Mallory's stain to analyse the general morphology and collagen arrangement; and smooth muscle actin, vascular endothelial growth factor (VEGF) and transforming growth factor β (TGFβ) receptors were immunolocalised.

RESULTS

Histological analysis of the wound tissue in the study indicated earlier wound contraction and collagen deposition in both treatment groups with re-organisation of the collagen (indicating collagen maturation) evident as early as at day 10.

CONCLUSION

The results of this study suggests that the leaf extracts increase tensile strength by increasing fibroplasia, differentiation of fibroblasts into myofibroblasts, and increased collagen deposition and maturation. This study further validates the use of the Bulbine leaf gels for the treatment of skin wounds.

The role of the platelet-rich plasma in accelerating the wound-healing process and recovery in patients being operated for pilonidal sinus disease: preliminary results

BACKGROUND

Because of the poor quality of life that results from the open technique (open excision and packing) for surgically treating pilonidal cyst disease, several alternatives that accelerate the wound-healing process have been proposed. This study aimed to evaluate the effect of platelet-derived growth factors on the healing process.

METHODS

Fifty-two patients with pilonidal sinus disease who underwent open excision and secondary closure of the surgical wound (n = 22) or additional local postoperative infusion of platelet-derived growth factors (n = 30) were evaluated. Duration of total wound healing and time to return to normal activities were evaluated. Quality of life of patients in each group was assessed via a stabilized questionnaire.

RESULTS

Wound-healing rates were much greater for the platelet group (p < 0.01). Complete healing of the surgical wound required 24 days for the platelet group while the respective time for the control group was more than 30 days (p < 0.01). Patients in the platelet group returned to their normal activities around the postoperative day 17 when mean wound volume was about 10 cc, while control group patients managed to do so around the postoperative day 25.

CONCLUSIONS

These data provide evidence that the use of platelet-derived growth factors directly to the surgical wound enhances the healing process resulting in faster recovery of patients surgically treated for pilonidal sinus disease.

Use of microparticulate systems to accelerate skin wound healing

Rapid and proper healing is important in the treatment of skin wounds. The dressing achieves the functions of the natural skin by protecting the wound area from the bulk loss of tissue and creating an effective barrier to outside contaminants without increasing the bacterial load on the wound surface. There are many wound dressings available on the market which can be used in the healing process. Different dressings have been used according to the condition of the wound and the phases of wound healing. Biodegradable polymers are being widely used in drug delivery and also in wound healing. These polymers that are applicable as a wound dressing protect the wound site against unwanted external effects, inhibit wound contraction, and, if possible, stimulate the healing process. Micro- and nanoparticulates are currently being evaluated as a potential drug delivery in clinical applications. Growth factors also play a vital role in wound healing. Polymers used in wound healing act as sustained release vehicles for growth factors. Controlled release of growth factors from microspheres has provided a higher degree of healing in the wound areas. This review is intended to provide information regarding the various formulations and microparticulate systems used in wound healing.