EHTIC study: Evaluation of a new hemostatic agent based on tissue factor in skin grafting procedures.

BACKGROUND: Excessive bleeding is a major concern in scar debridement and grafting procedures. TT-173 is a new topical hemostatic agent based on recombinant human tissue factor that has shown promising results in patients who underwent tooth extraction. EHTIC study sought to evaluate the efficacy and safety of TT-173 to reduce the bleeding in donor sites of skin grafting procedures. METHODS: EHTIC study was a phase II, randomized, parallel, double blind, placebo controlled trial. Patients received TT-173 (n=38) or placebo (n=33) sprayed over donor site after graft harvest. Time to hemostasis and incidence of adverse events were recorded. Systemic absorption of the product and its immunogenicity were also measured during the follow up of the subjects. RESULTS: Treatment with TT-173 significantly reduced the bleeding time from 7 to 3min (Log-Rank p<0.0001). Moreover, bleeding stopped within the 10min of evaluation period in all the patients that received TT-173. In contrast, 24.24% of patients from placebo group required additional measures to arrest hemorrhage (Fisher p=0.0013). Product related adverse events, systemic absorption into blood stream, interferences with the healing of the donor site or immunogenic reaction against TT-173 were not observed. CONCLUSION: The new hemostatic agent TT-173 has proven efficacious and safe to reduce the bleeding from donor site. This study paves the way for further investigation of the product as topical hemostatic treatment in plastic surgery and other surgical indications.

Production of an acellular matrix from amniotic membrane for the synthesis of a human skin equivalent.

Human amniotic membrane (HAM) has useful properties as a dermal matrix substitute. The objective of our work was to obtain, using different enzymatic or chemical treatments to eliminate cells, a scaffold of acellular HAM for later use as a support for the development of a skin equivalent. The HAM was separated from the chorion, incubated and cryopreserved. The membrane underwent different enzymatic and chemical treatments to eliminate the cells. Fibroblasts and keratinocytes were separately obtained from skin biopsies of patients following a sequential double digestion with first collagenase and then trypsin-EDTA (T/E). A skin equivalent was then constructed by seeding keratinocytes on the epithelial side and fibroblasts on the chorionic side of the decellularizated HAM. Histological, immunohistochemical, inmunofluorescent and molecular biology studies were performed. Treatment with 1% T/E at 37 °C for 30 min totally removed epithelial and mesenchymal cells. The HAM thus treated proved to be a good matrix to support adherence of cells and allowed the achievement of an integral and intact scaffold for development of a skin equivalent, which could be useful as a skin substitute for clinical use.

Design and creation of an experimental program of advanced training in reconstructive microsurgery.

In this study, we design an experimental protocol for the purpose of enhancing performance in training in microsurgery. It is based on five free tissue transfer exercises in rat (epigastric cutaneous flap, saphenous fasciocutaneous flap, epigastric neurovascular flap, saphenous muscular flap, and hindlimb replantation), which simulate the principal clinical procedures of reconstructive microsurgery. The first part of the study consists of an anatomical review of the flaps of 5 rats and in the second part we have carried out the free transfer of flaps on 25 rats divided into 5 groups. To differentiate between them, we have created a mathematical function, referred to as difficulty in a microsurgical exercise, which has enabled us to establish a scale of progression for training, ranging form the easiest to the most difficult. As a conclusion, we believe that this protocol is a useful instrument as it allows for a more precise assessment of microsurgical capacity due to enhanced accuracy in the reproduction of global procedures and the fact that the quantification of progress in training is based on clinical monitoring after 7 days.