The long-term objective of this study is to define the mechanisms resulting in the defective or delayed re-epithelization seen in chronic wounds and ultimately develop an in vitro experimental model of the chronic wound environment. Specifically, the study will aim to: 1) determine if there is a decrease in fibronectin messenger RNA (mRNA) expression when cells are exposed to chronic wound fluids in vitro compared to serum and acute wound fluid; 2) examine mRNA expression in keratinocytes and fibroblasts in human tissue sections from chronic wounds compared to acute wounds and unwounded skin tissue; and 3) determine whether a decrease in mRNA expression in chronic wound fluids is associated with a coordinate decrease in fibronectin receptor expression. The sample will consist of a total of 40 adult males and females (10/group), who are 18 to 95 years of age. Subjects will be normal adults who have had surgical mastectomies, and those with venous leg ulcers and pressure ulcers. To be included, an individual with a venous ulcer or a pressure ulcer must have not healed for one year, or healed at a rate of <1 mm/week. Subjects will be selected from the patient population of New York University Medical Center.
Specific Aim I will be studied by collecting wound fluid from mastectomy incision drains, venous and pressure ulcers, and analyzing fibronectin mRNA expression in baby hamster kidney cells exposed to these fluids in culture. Standard Northern blot analysis will be used to determine if there is a decrease in fibronectin mRNA expression when cells are exposed to chronic wound fluids.
Specific Aim II will employ in situ hybridization to examine mRNA expression in keratinocytes, and fibroblasts found in human tissue sections taken from venous ulcers, pressure ulcers, acute surgical wound tissue and normal skin tissue.
Specific Aim III will observe fibronectin receptor (integrin receptor) expression using antibodies against alpha-5 B-1, and then examine tissue sections and cells exposed to chronic wound fluid by immunofluorescence.
| Wysocki, A B (1996) Wound fluids and the pathogenesis of chronic wounds. J Wound Ostomy Continence Nurs 23:283-90 |
