Adhesion molecules and wound healing in spinal cord injury

The purpose of this study was to design and test a model that could identify and define which cellular adhesion molecules (CAMs) present on peripheral blood leukocytes were depressed in spinal cord injury (SCI) patients. CAMs on peripheral blood cells of SCI patients with pressure ulcers were measured by flow cytometry and compared with those of age-matched healthy controls and SCI patients on physical rehabilitation therapy (PRT) protocols without pressure ulcers. The latter patients had normal levels (97%) of lymphocyte function-associated antigen 1 (LFA-1; CD11a/CD18) and a low incidence of infection. By contrast, prior to undergoing rehabilitation therapy, SCI patients with pressure ulcers had significantly diminished LFA-1 levels (62%). Very late antigen 4 (VLA-4; alpha 4 beta 1; 34%) levels (i.e., alpha 4 = 34% and beta 1 = 44%) were approximately half those in controls (72%). Expression of alpha 2 and alpha 3 was also diminished in patients. Patients receiving PRT after debridement developed increased levels of LFA-1 and VLA-4 by the 6th week but alpha 2 and alpha 3 remained relatively low. These results combined with data from previous studies suggest that patients not receiving PRT developed severe pressure ulcers which required debridement surgery and healed more slowly due, in part, to reduced levels of CAMs.