Biomedical Engineering Reference
In-Depth Information
fibroblasts as a feeder layer because graft rejection may possibly be associated
with the presence of xenogeneic antigens. The layers of Laserskin
®
with autolo-
gous keratinocytes and either allogeneic or autologous dermal fibroblasts were
grafted onto the vascularised neodermis of Integra
®
(a bilayer artificial skin,
Integra
®
LifeSciences, Plainsboro NJ, consisting of a layer of porous collagen-
GAG with a thin outer silicone membrane) immediately after the removal of the
silicone membrane. Although there maybe obvious potential problems with the
allogeneic approach, for example disease transmission and immunologic effects,
a burns patient was successfully treated for contracture release by this method.
Two other patients with congenital nevus were treated using the autologous
fibroblast approach. There may be an additional benefit of using autologous
dermal fibroblasts in that they produce a number of proteins such as collagen and
fibronectin that may enhance graft attachment and stability.
Vitiligo
Sheets of Laserskin
®
without dermal replacements have been used for the treat-
ment of vitiligo (Andreassi
et al
., 1998). The achromatic area was de-epithelised
and Laserskin
®
previously inoculated with autologous keratinocytes and lethally
irradiated 3T3 cells was applied. Good repigmentation rates were reported (10 out
of 11) with the only failure being associated with sepsis, demonstrating that
stability of grafts can be an issue in even relatively minor procedures if wound bed
conditions are not optimal. However, the effectiveness is reported as being greater
than that of unsupported sheets of CEA.
Ulcers
A small number of studies have been conducted on the use of Laserskin
®
as a
material for chronic wound closure. A large, multicentre, retrospective, uncon-
trolled study was performed in Italy (Uccioli, 2003) evaluating the TissueTech
Autograft System (TTAS) combining autologous fibroblast cultures within a
HYAFF based three-dimensional matrix (Hyalograft-3D
®
) with Laserskin
®
ap-
plied as the epidermal layer. Diabetic lower extremity ulcers, venous ulcers,
arterial ulcers, traumatic wounds, pressure ulcers and others were studied in 401
patients from 60 different centres. Complete closure was reached for 70.3% of the
ulcers with a mean observation time of 330 days and 63% of those healed within
four months. The rate of recurrence was 8.2% (Uccioli, 2003). These figures are
comparable to other studies using TTAS (Caravaggi
et al
., 2003) and are slightly
higher than studies investigating the effectiveness of allogeneic skin substitutes.
As this study was purely descriptive, there were no controls for comparison.
However, figures for control groups have been cited in studies investigating other
treatments and the healing rates were between 30 and 40%.
Two further studies investigated the use of Laserskin
®
for treating chronic
