Silicone-coated non-woven polyester dressing enhances reepithelialisation in a sheep model of dermal wounds

Evaluation of a polyurethane foam dressing impregnated with 3% povidone-iodine (Betafoam) in a rat wound model

Purpose

The purpose of this study was to evaluate the efficacy of Betafoam in terms of wound healing and safety.

Methods

Fifty-four male adult Sprague-Dawley rats (weight, 200–250 g) were used in the study. Full-thickness skin defects were created on the back of each rats. The rats were assigned to 6 groups according to the type of wound dressing used (n = 9 for each group): Betafoam, Allevyn-Ag, Mepilex-Ag, Medifoam silver, Polymem-Ag, and gauze. The wound size, histological findings, and amount of DNA on the changed dressings for each group were analyzed and compared.

Results

All groups showed an effective decrease in wound size. However, the differences between Betafoam and the other dressings were statistically significant on day 14 (P < 0.05). The number of newly generated blood vessels in the Betafoam group was significantly higher than in the gauze, Allevyn-Ag, and Medifoam silver groups (P < 0.001). In the Betafoam group, the proportion of collagen deposition was highest and showed a significantly superior arrangement of collagen fibers compared with the gauze, Allevyn-Ag, Mepilex-Ag, and Medifoam silver groups. The total content of the remaining DNA counts of the exchanged dressings were significantly lower in the Betafoam group than the others.

Conclusion

Betafoam is effective in wound healing and provides the best performance amongst the various types of dressing materials in terms of re-epithelialization, angiogenesis, collagen deposition, and tissue invasion.

Future Prospects for Scaffolding Methods and Biomaterials in Skin Tissue Engineering: A Review

Over centuries, the field of regenerative skin tissue engineering has had several advancements to facilitate faster wound healing and thereby restoration of skin. Skin tissue regeneration is mainly based on the use of suitable scaffold matrices. There are several scaffold types, such as porous, fibrous, microsphere, hydrogel, composite and acellular, etc., with discrete advantages and disadvantages. These scaffolds are either made up of highly biocompatible natural biomaterials, such as collagen, chitosan, etc., or synthetic materials, such as polycaprolactone (PCL), and poly-ethylene-glycol (PEG), etc. Composite scaffolds, which are a combination of natural or synthetic biomaterials, are highly biocompatible with improved tensile strength for effective skin tissue regeneration. Appropriate knowledge of the properties, advantages and disadvantages of various biomaterials and scaffolds will accelerate the production of suitable scaffolds for skin tissue regeneration applications. At the same time, emphasis on some of the leading challenges in the field of skin tissue engineering, such as cell interaction with scaffolds, faster cellular proliferation/differentiation, and vascularization of engineered tissues, is inevitable. In this review, we discuss various types of scaffolding approaches and biomaterials used in the field of skin tissue engineering and more importantly their future prospects in skin tissue regeneration efforts.

Allogenous skin fibroblast transplantation enhances excisional wound healing following alloxan diabetes in sheep, a randomized controlled trial

BACKGROUND

Healing of skin wound is a multi-factorial and complex process. Treatment of diabetic wounds is still a major clinical challenge. Recently, stem cell transplantation to chronic wounds is favored. The objective of this study was to evaluate effects of pre-labeled allogenous skin fibroblasts on healing of ovine diabetic wound model.

METHODS

Eight 4-month-old Iranian Makoui wethers were used in this study. Alloxan monohydrate was used for induction of diabetes. In each wether two excisional wound were created on dorsum of the animal. Wounds of one side were randomly chosen as treatment group (n = 8), and wounds of the other side were considered as control group (n = 8). Pre-labeled skin fibroblasts with bromodeoxyuridine were used in wounds of one side as treatment. Photographs were taken in distinct times for planimetric evaluation. Wound samples were taken for BrdU detection and histopathologic evaluations on day 21 post-wounding.

RESULTS

The planimetric study showed closure of fibroblast treated wounds is significantly faster than control group (P < 0.05). Immunohistochemical staining with anti-bromodeoxyuridine antibody indicated presence of transplanted cells in the wounds. Histopathologic evaluations of H&E stained sections disclosed significantly increasing of re-epithelialization, number of fibroblasts, and number of blood vessels in treatment group in comparison to control group (P < 0.05).

CONCLUSION

[corrected] The results of this study indicated that allogenous skin fibroblast transplantation can positively affect wound healing in diabetic sheep.

Natural and synthetic polymers for wounds and burns dressing

In the last years, health care professionals faced with an increasing number of patients suffering from wounds and burns difficult to treat and heal. During the wound healing process, the dressing protects the injury and contributes to the recovery of dermal and epidermal tissues. Because their biocompatibility, biodegradability and similarity to macromolecules recognized by the human body, some natural polymers such as polysaccharides (alginates, chitin, chitosan, heparin, chondroitin), proteoglycans and proteins (collagen, gelatin, fibrin, keratin, silk fibroin, eggshell membrane) are extensively used in wounds and burns management. Obtained by electrospinning technique, some synthetic polymers like biomimetic extracellular matrix micro/nanoscale fibers based on polyglycolic acid, polylactic acid, polyacrylic acid, poly-ɛ-caprolactone, polyvinylpyrrolidone, polyvinyl alcohol, polyethylene glycol, exhibit in vivo and in vitro wound healing properties and enhance re-epithelialization. They provide an optimal microenvironment for cell proliferation, migration and differentiation, due to their biocompatibility, biodegradability, peculiar structure and good mechanical properties. Thus, synthetic polymers are used also in regenerative medicine for cartilage, bone, vascular, nerve and ligament repair and restoration. Biocompatible with fibroblasts and keratinocytes, tissue engineered skin is indicated for regeneration and remodeling of human epidermis and wound healing improving the treatment of severe skin defects or partial-thickness burn injuries.