Do Functional Keratin Dressings Accelerate Epithelialization in Human Partial Thickness Wounds?

A Randomized Controlled Trial on Skin Graft Donor Sites

Andrew Davidson, MBChB; N. Hamesh Jina, MBChB; Clive Marsh, PhD; Martin Than, MBBS; Jeremy W. Simcock, MD


ePlasty. 2013;13 

In This Article


Older patients healed their partial-thickness wounds more slowly; however, there was significantly more epithelialization after 7 days in wound portions treated with the keratin-based dressing compared with standard care. This implies that the time to complete epithelialization may be reduced in the portion of the wound treated with the keratin-based dressing, for the older patients. This study also demonstrated rapid epithelialization of split skin graft donor sites in young patients. This is consistent with previous reports[15] and reflects ideal wound healing. There was no significant difference in epithelization rates between Treatment and Control dressings for younger patients.

Delayed epithelialization is commonly caused by both patient factors (age and comorbidities) and wound factors (deep partial-thickness injuries including deep dermal burns) and is associated with wound complications such as infection and scarring.[16] Thus, mitigation of delayed epithelialization is of clinical significance and the results suggest that keratin-based dressings can achieve this in some cases. The clinical implications of this study are that keratin-based dressings can reduce the delayed epithelialization seen in predisposed patients and so reduce the complications of healing in this group of patients. The results may extrapolate from these traumatic, acute partial-thickness wounds to thermal, acute partial-thickness wounds such as burns.

The results of this study are consistent with the proposed mechanism of action and with earlier published preclinical results and other clinical studies. The proposed mechanism, as described in the "Introduction," is that the exogenous keratin can stimulate keratinocytes via the Akt/mTOR signalling pathway. The clinical observations in this study are consistent with such stimulated keratinocyte activity. However, ethical considerations did not permit biopsy to permit investigation of the response to the Treatment at a cellular level. Furthermore, both preclinical animal studies[5] and other clinical studies[6–8] showed similar increases in epithelialization rates and are consistent with the findings of this study.

Questionnaires, completed by nurses, indicated that the Treatment dressing was well tolerated by patients, and ease of removal was at least comparable to current standard care. Although there was more coagulated blood on the surface of the Treatment side of wounds, this does not seem to have adversely affected the ease of dressing removal or the rate of epithelialization and healing.

Potential criticism of this study includes the small sample size, especially given the heterogeneity of this patient population. However, the use of internal controls meant that we were able to detect significant difference between Treatment and Control dressings. The wide range of epithelialization rates observed in this study supports using internal controls in the investigation of partial-thickness wound healing rates. The method of assessment, estimation of percentage of epithelialization by a skilled, blinded assessor, is novel. As expected, the neoepithelium was observed to be in patches around the epidermal appendages and the visual assessment method was found to be appropriate to estimate the percentage epithelialization. A weakness of the assessment technique is that it is difficult to repeat, the skilled assessor was confident in his ability to assess "in the flesh" but the digital images were unable to capture detail necessary to make the assessments of percentage epithelialization and hence assessments from the digital images are not reproducible.

Ideally, time to complete epithelialization could be measured for each patient, but a method that observes the wounds daily as they near complete epithelialization is onerous and disruptive for patient's healing. Thus, this method of a single observation at 7 days was used. We suggest that there will be a strong, direct relationship between the percentage epithelialization after 7 days and time to complete epithelialization.