Chronic lower limb ulcers treatment with autologous skin equivalent and larvae debriding (diptera calliphoridae)

Abstract

Introduction: Lower limb ulcers are an important cause of hospitalization and deterioration of life quality because they affect both the work and social activities of patients. These ulcers are due to different diseases, the most common of which, in Medellín, Colombia, is venous insufficiency. After diagnosis, there are many management options, all of them looking for an appropriate environment for wound healing.

The use of larvae for debridement is a low-cost alternative which minimizes pain and discomfort of patients and stimulates the growth of a healthy granulation tissue for application of an autologous skin equivalent, the choice for patients that have not responded to other treatments.

Materials and methods: The selected patient was evaluated and the requirement of larvae debridement was determined. Lucilia sp. (Diptera: Calliphoridae) larvae were obtained from eggs previously desinfected and seeded in a culture medium with antibiotics. The larvae were applied directly onto the ulcer and then covered with a sterile tulle, that allowed tissue oxygenation and necrotic material elimination. They were left on the ulcer during 48 hours, after which they were discarded in alcohol 70%; debridement was then evaluated. This procedure was carried out at the Entomology Laboratory (GIEM), University of Antioquia, Medellín, Colombia.

Keratinocytes and fibroblasts were obtained from a skin specimen taken according to the established protocol. For keratinocytes primary culture, 90% of the cells obtained from the biopsy were seeded in 75 cm2 culture plates, over a feeding monolayer of 7 x 106 3T3-Swiss cells treated with mitomycin C. For fibroblasts primary culture, 10% of the cells were seeded in 75 cm2 culture plates, containing DMEM supplemented medium. For the production of the skin equivalent, AB human plasma from a blood bank, 6-7,5 x 104 fibroblasts, CaCl2 and tranexamic acid were used in order to obtain a gel; keratinocytes obtained in the primary culture were placed on this gel and the culture was followed-up under an inverted microscope. When cell confluence was near 100%, the skin equivalent was covered with a sterile tulle, and detached for its immediate application on the ulcer.

We report the case of a 66 year old woman treated for a leg ulcer with larvae debridement and autologous skin equivalent. After being followed up for 15 months the ulcer continues closed, no pain has been reported and the leg function is normal.