Charged beads enhance cutaneous wound healing in rhesus non-human primates

Enhanced cutaneous wound healing by positively charged cross-linked diethyl aminoethyl dextran beads (CLDD) was studied in a standardized incisional wo und model in 20 adult and 20 geriatric Macaca mulatta (rhesus) partitioned equally over five time periods. Physiologic saline served as a control. Sof t-tissue linear incisions were prepared between and 1 cm inferior to the sc apulae. There were four incisions per rhesus; each incision was 1.5 cm long with 1 cm of undisturbed tissue between incisions, and both the experiment al CLDD and physiologic saline treatments were administered to each rhesus. The incision treatments were either CLDD and soft-tissue closure with 4-0 BioSyn sutures or sterile physiologic saline and closure with 4-0 BioSyn su tures. The hypothesis was CLDD would enhance cutaneous wound repair. Verifi cation of the hypothesis consisted of clinical examinations and histologic and tensiometric evaluations on biopsy specimens at 10 and 15 days, whereas 5-day and 2- and 4-month groups were assessed clinically and biopsy specim ens were assessed histologically. The clinical course of healing for all groups tvas unremarkable. At 10 days , incisions in adult rhesus treated dth CLDD had a 30-percent greater tensi le strength compared with;the physiologic saline-treated incisions (p = 0.0 1), whereas for geriatric rhesus, the CLDD treatment proved to be 15 percen t greater in tensile strength compared with the physiologic saline cohort ( p = 0.11). By day 15, incisions ill adult rhesus were 26 percent stronger t han the saline treatment group (p = 0.07), and the difference was 36 percen t (p = 0.02) for the geriatric rhesus. From 5 through 15 days, histologic o bservations revealed a gradual decrease in quantity and integrity of CLDD, with no remnants of CLDD at either 2 or 4 months. Macrophages and multinucl eated giant cells were localized in the dermis and were associated with the CLDD. These cells decreased commensurately with the decrease of CLDD beads . The data suggest that CLDD can enhance significantly the tensile properties of healing cutaneous wounds in both adult and geriatric rhesus. Moreover, if the wound healing is enhanced in geriatric patients, this finding may be clinically germane to conditions where wound healing is compromised, such as in diabetics and patients on steroids.