SEMIPERMEABLE DRESSINGS IMPROVE EPIDERMAL BARRIER FUNCTION IN PREMATURE-INFANTS

Infants of less than 32 wk gestation have a defective epidermal barrie r, with increased skin permeability and transepidermal water loss (TEW L). We studied the effect of a nonadhesive semipermeable dressing on t he epidermal barrier of premature infants and on fetal skin transplant ed to nude mice. Fifteen infants with a mean estimated gestational age of 27.7 wk and 16 human fetal skin grafts (estimated gestational age, 23-26 wk) transplanted to eight nude mice were studied. One lower leg (or skin graft) was treated and the other left untreated as a control . In the infants, TEWL was measured on control skin and treated skin ( both through the dressing and after temporary dressing removal) on d 0 , 1, 2, 4, and 7. Bacterial and fungal cultures were also performed. I n the mice, TEWL and skin blood flow were measured on d 0, 2, and 4. B iopsies were obtained on d 4 for a cell proliferation assay, histology , and electron microscopy. Treated infant skin showed a consistently l ower bacterial number and a significantly decreased TEWL (measured thr ough the dressing). There was also a significantly lower TEWL on the t reated side, measured after temporary dressing removal, on d 1, 2, 4, and 7, documenting improved epidermal barrier function. The animal stu dy revealed decreased TEWL and a nearly 2-fold greater d-4 keratinocyt e proliferation (p = 0.01) in treated skin and decreased blood flow on d 4 in control skin (p = 0.01). There was no significant difference i n the volume density of membrane coating granules or the morphology of intercorneocyte spaces. It is concluded that semipermeable dressings improve epidermal barrier function without increasing bacterial or fun gal colonization in premature infants, and that increased cellular pro liferation is associated with improved barrier function in semipermeab le dressing-treated fetal skin.