Efficacy and safety of hyaluronic acid in the management of acute wounds

Initial Experience Using a Hyaluronate-Iodine Complex for Wound Healing

Hyaluronate-iodine complex is a wound healing adjuvant approved for use in the European Union. The objective of this study is to validate hyaluronate-iodine as a potential wound healing agent. Patients were recruited from the hospital, the outpatient clinic, and the wound healing center. Hyaluronate-iodine soaked gauze was applied to wounds either daily or every other day depending on the amount of wound exudate. Wounds were measured weekly, and progression was documented with digital photography. All wounds were debrided as needed using standard surgical techniques. Fourteen patients (19 wounds) were entered into this prospective study, and 10 patients completed treatment. Fourteen wounds progressed to complete healing with a mean healing time of 18.1 ± 15.1 weeks. Treatment was interrupted in four patients. One patient discontinued treatment due to pain related to application of hyaluronate-iodine, another patient for transportation issues, and the other two patients were lost to follow-up due to relocation out of state and noncompliance with scheduled appointments. Hyaluronate-iodine was helpful in the healing of all types of wounds treated in this pilot study. The antiadhesive and antimicrobial properties of hyaluronate-iodine create a desirable environment conducive to wound healing without apparent detrimental effects.

Fibroblast function and wound breaking strength is impaired by acute ethanol intoxication

BACKGROUND

Alcohol intoxication occurs in nearly half of all trauma patients and increases the morbidity, mortality, and healing complications of these patients. Prior studies in our laboratory and elsewhere have demonstrated impairments in re-epithelialization, angiogenesis, and inflammation in wounds following acute ethanol exposure. Clinically, acute ethanol exposure has been shown to cause an increased breakdown of wounds. To date, the mechanisms by which acute ethanol exposure modifies wound strength have received little experimental attention.

METHODS

To examine how ethanol influences functions critical to the development of wound strength, the effect of ethanol exposure on fibroblast proliferation and extracellular matrix production was examined. Normal human dermal fibroblasts (NHDF) were exposed to ethanol (100 mg/dl) and then examined for proliferative capacity and mRNA production of collagen I, collagen III, and lysyl oxidase (LOX). In in vivo studies, the wound breaking strength, LOX activity, collagen, and hyaluronic acid (HA) contents of wounds of ethanol-exposed (100 mg/dl) mice were examined.

RESULTS

At 24, 48, and 72 hours after acute ethanol exposure (8 hours duration), NHDF displayed a significant impairment in proliferative capacity (up to 50% at 24 hours p < 0.001). After ethanol exposure, NHDF produced less collagen I and LOX mRNA, but more collagen III mRNA than control fibroblasts (p < 0.05). Ethanol exposure in vivo caused a reduction in wound breaking strength of up to 40% when compared to control mice (p < 0.01). LOX activity, collagen, and HA contents in the wounds of ethanol-exposed mice were significantly reduced (p < 0.01).

CONCLUSIONS

These studies reveal that a single exposure to ethanol prior to injury can cause a significant decrease in wound breaking strength. Our studies suggest that ethanol directly impairs fibroblast function, leading to decreased collagen production. The results provide a possible explanation for how acute ethanol exposure might increase in wound complications and wound failure.

A physiologically active polysaccharide hydrogel promotes wound healing

When the skin is injured, the subcutaneous tissues and organs are threatened by pathogens and excessive water loss. Wound dressings are, therefore, needed to protect the wound site from infection and improve the wound closure. Natural polysaccharides have been applied for various biomaterials including wound dressings, which show their advantages in biocompatibility, low toxicity, and pharmaceutical biomedical activity. In this study, a natural polysaccharide Bletilla striata polysaccharide (BSP) hydrogel is prepared by an oxidation and crosslinking methods. This BSP hydrogel represents preferable swelling ability and appropriate water vapor transmission rate. Using a full-thickness trauma mouse model, the hydrogel is applied on the in vivo cutaneous wound healing. Compared with the control groups, the BSP hydrogel achieves the much better healing results. The quantification of the infiltrating inflammatory cells and the level of tumor necrosis factor alpha (TNF-alpha) in the BSP group are attenuated, whereas the secretion of the epidermal growth factor (EGF) is highly elevated. On the 11th day after surgery, the wound area in the BSP hydrogel group is only 1/5-1/3 of those in the control groups. This new BSP hydrogel is proved to control the inflammatory responses and accelerate the wound closure and has potential application in wound healing. (c) 2010 Wiley Periodicals, Inc. J Biomed Mater Res, 2010.

Wound healing dressings and drug delivery systems: a review

The variety of wound types has resulted in a wide range of wound dressings with new products frequently introduced to target different aspects of the wound healing process. The ideal dressing should achieve rapid healing at reasonable cost with minimal inconvenience to the patient. This article offers a review of the common wound management dressings and emerging technologies for achieving improved wound healing. It also reviews many of the dressings and novel polymers used for the delivery of drugs to acute, chronic and other types of wound. These include hydrocolloids, alginates, hydrogels, polyurethane, collagen, chitosan, pectin and hyaluronic acid. There is also a brief section on the use of biological polymers as tissue engineered scaffolds and skin grafts. Pharmacological agents such as antibiotics, vitamins, minerals, growth factors and other wound healing accelerators that take active part in the healing process are discussed. Direct delivery of these agents to the wound site is desirable, particularly when systemic delivery could cause organ damage due to toxicological concerns associated with the preferred agents. This review concerns the requirement for formulations with improved properties for effective and accurate delivery of the required therapeutic agents. General formulation approaches towards achieving optimum physical properties and controlled delivery characteristics for an active wound healing dosage form are also considered briefly.

Hyalomatrix: a temporary epidermal barrier, hyaluronan delivery, and neodermis induction system for keratinocyte stem cell therapy

Keratinocyte stem cell technology provides at least an adjuvant therapy to clinically close large cutaneous wounds (e.g., burn wounds). Here, the performance of keratinocyte cultures depends primarily on the quality of the bed to which they are applied. Clinical take rates for cultured keratinocyte grafts are optimal when applied to a vascularized dermal bed with minimal bacterial colonization. In the absence of autologous dermis, staged reconstruction with a dermal equivalent or dermal regeneration template is required. A novel product, Hyalomatrix, is a bilayer of an esterified hyaluronan scaffold beneath a silicone membrane. The scaffold delivers hyaluronan to the wound bed, and the silicone membrane acts as a temporary epidermal barrier. The product has been investigated in a controlled, porcine, acute full-thickness excisional wound model. Cultured autologous keratinocytes (CAKs) were delivered on Laserskin to acute full-thickness wounds treated with Hyalomatrix within chambers, and graft take rates were assessed longitudinally using image analysis. In the absence of chambers, wound contraction was assessed. Clinical CAK take rates fall sequentially with delay in application post-Hyalomatrix pre-treatment, but repeated pre-treatment removed this, with maximal take of 57.2% at 5 weeks post-wounding. In the absence of chambers, more-complete wound closure resulted from edge re-epithelialization and contraction, by a factor of 5 at 1 month, and was achieved at least 2 weeks sooner in the gold standard controls of split-thickness autograft to an acute or pre-treated wound bed. Wound contraction and late neodermal morphology (1 year) were similar in pre-treated CAKs and split-thickness autograft wounds. In this model, the Hyalomatrix wound bed pre-treatment increase in CAK take appeared to be dose dependent. The product appeared to act as a hyaluronan delivery system rather than a dermal regeneration template. The silicone membrane may limit wound bed colonization, and the combination of this temporary barrier with hyaluronan delivery and neodermis induction has been termed a barrier-delivery-induction system. The development of similar systems for serial application offers an alternative to a dermal regeneration template when CAKs are engrafted in the hostile, colonized environment of large burn wounds.