Intractable wounds caused by arteriosclerosis obliterans with end-stage renal disease treated by aggressive debridement and epidermal grafting

An Automated and Minimally Invasive Tool for Generating Autologous Viable Epidermal Micrografts

OBJECTIVE:

A new epidermal harvesting tool (CelluTome; Kinetic Concepts, Inc, San Antonio, Texas) created epidermal micrografts with minimal donor site damage, increased expansion ratios, and did not require the use of an operating room. The tool, which applies both heat and suction concurrently to normal skin, was used to produce epidermal micrografts that were assessed for uniform viability, donor-site healing, and discomfort during and after the epidermal harvesting procedure.

DESIGN:

This study was a prospective, noncomparative institutional review board–approved healthy human study to assess epidermal graft viability, donor-site morbidity, and patient experience.

SETTING:

These studies were conducted at the multispecialty research facility, Clinical Trials of Texas, Inc, San Antonio.

PATIENTS:

The participants were 15 healthy human volunteers.

RESULTS:

The average viability of epidermal micrografts was 99.5%. Skin assessment determined that 76% to 100% of the area of all donor sites was the same in appearance as the surrounding skin within 14 days after epidermal harvest. A mean pain of 1.3 (on a scale of 1 to 5) was reported throughout the harvesting process.

CONCLUSIONS:

Use of this automated, minimally invasive harvesting system provided a simple, low-cost method of producing uniformly viable autologous epidermal micrografts with minimal patient discomfort and superficial donor-site wound healing within 2 weeks.

Clinical and Economic Benefits of Autologous Epidermal Grafting

Chronic wounds are an increasingly prevalent disease with a significant healthcare burden. These wounds often do not respond to standard of care therapy alone, requiring the use of adjuvant therapies. Epidermal grafting, previously utilized primarily for correction of leukoderma, is increasingly being recognized as a beneficial therapy for wounds, both acute and chronic. Epidermal grafting has been shown to be effective in the management of chronic wounds, with successful healing in refractory patients. It has not only been shown to be effective, but it is also associated with lower cost and morbidity than traditional skin grafting techniques as well as improved donor site healing. Through the use of a novel epidermal harvesting system, the CelluTome™ Epidermal Harvesting System (KCI, an Acelity company, San Antonio, TX), this treatment modality has become more standardized, reproducible, and easy to use as well as less time consuming, making its use in the clinical setting more convenient and beneficial. Epidermal grafting, therefore, represents a promising, efficacious, and cost-effective option for treatment of refractory non-healing wounds.

Epidermal skin grafting

Autologous skin grafts, such as full- and split-thickness, have long been part of the reconstructive ladder as an option to close skin defects. Although they are effective in providing coverage, they require the need for a trained surgeon, use of anaesthesia and operating room and creation of a wound at the donor site. These drawbacks can be overcome with the use of epidermal skin grafts (ESGs), which can be harvested without the use of anaesthesia in an office setting and with minimal to no scarring at the donor site. ESGs consist only of the epidermal layer and have emerged as an appealing alternative to other autologous grafts for the treatment of acute and chronic wounds. In this article, we provide an overview of epidermal grafting and its role in wound management.

Use of epidermal grafts in wounds: a review of an automated epidermal harvesting system

Chronic wounds continue to present a significant challenge to health-care providers across the globe. Unlike acute wounds, chronic wounds do not proceed through an orderly process of repair. In recent years, a number of wound healing treatments, such as dermal replacement scaffolds and negative pressure wound therapy, have promoted wound healing by stimulating the formation of granulation tissue. However, until recently there were few modalities designed to promote epithelialisation of a fully granulated wound. Split-thickness skin grafts (STSGs) have long been the gold standard for the management of acute wounds, but have not gained favour in the treatment of chronic wounds for several reasons: discomfort associated with the donor site, the creation of a second wound (donor site) in a patient with poor wound-healing potential, and a lack of documented efficacy for the procedure. Epidermal grafting does not have some of the limitations encountered with STSG; however, it has not gained wide acceptance, as previous harvesting techniques were cumbersome and time-consuming. A novel automated epidermal harvesting system, CelluTome Epidermal Harvesting System (KCI, an Acelity company, San Antonio, TX, USA), was commercially introduced in 2013. The system yields up to 128 epidermal micrografts that can be easily harvested at the bedside without anaesthesia and transferred to the recipient site. The harvesting technique and the use of epidermal grafts in wounds are reviewed here.

Takayasu arteritis and ulcerative cutaneous sarcoidosis

A 67-year-old woman was referred to our hospital due to a refractory lower extremity ulcer. Occlusion of the bilateral superficial femoral arteries and a difference (>50 mmHg) in blood pressure between the bilateral upper limbs were noted. In addition to occlusion of the left subclavian artery and stenosis at the ostium of the right coronary artery, these findings led to a diagnosis of Takayasu arteritis. Furthermore, a biopsy of the ulcerated skin lesion localized on the fibular surface showed a non-caseating cutaneous granulomatous lesion resulting in the diagnosis of cutaneous sarcoidosis. The simultaneous occurrence of cutaneous sarcoidosis and Takayasu arteritis, albeit rare, should not be overlooked.

Regulation of skin pigmentation and thickness by Dickkopf 1 (DKK1)

Dickkopf 1 (DKK1), an inhibitor of Wnt signaling, not only functions as a head inducer during development, but also regulates joint remodeling and bone formation, which suggests roles for DKK1 in the pathogenesis of rheumatoid arthritis and multiple myeloma. We recently demonstrated that levels of DKK1 in palmoplantar dermal fibroblasts are physiologically higher than those observed in non-palmoplantar dermal fibroblasts. Thus, the DKK1-rich mesenchyme in palmoplantar dermis affects the overlying epithelium and induces a palmoplantar phenotype in the epidermis. More specifically, DKK1 suppresses melanocyte function and growth through the regulation of microphthalmia-associated transcription factor (MITF) and beta-catenin. Furthermore, DKK1 induces the expression of keratin 9 and alpha-Kelch-like ECT2-interacting protein (alphaKLEIP) but downregulates the expression of beta-catenin, glycogen synthase kinase 3beta, protein kinase C, and proteinase-activated receptor-2 (PAR-2) in keratinocytes. Treatment of reconstructed skin with DKK1 reproduces the hypopigmentation and thickening of skin through Wnt/beta-catenin signaling. These studies elucidate why human palmoplantar skin is thicker and paler than non-palmoplantar skin through the secretion of DKK1 by fibroblasts that affect the overlying epidermis. Thus, DKK1 may be useful for reducing skin pigmentation and for thickening photo-aged skin and palmoplantar wounds caused by diabetes mellitus and rheumatic skin diseases.Journal of Investigative Dermatology Symposium Proceedings (2009) 14, 73-75; doi:10.1038/jidsymp.2009.4.