HUMAN ALBUMIN SOLDER SUPPLEMENTED WITH TGF-BETA(1) ACCELERATES HEALING FOLLOWING LASER WELDED WOUND CLOSURE

Background and Objective: We examined the possibility that human album in solder can be used as a vehicle for site specific delivery of growt h factors for the purpose of accelerating tissue repair following lase r welded wound closure. Certain human recombinant growth factors have been shown to accelerate wound healing in model systems. Pilot in vitr o studies have established that several growth factors, including TGF- beta(1), maintain bioactivity following exposure to temperatures achie ved during laser tissue welding. Using a temperature controlled laser delivery system (TCL) to precisely maintain welding temperatures, it i s now possible to avoid thermal denaturation of exogenous bioactive mo lecules such as growth factors. Study Design/Materials and Methods: HB -EGF, bFGF, and TGF-beta(1) were tested in vitro for maintenance of bi oactivity after exposure to 80 degrees C. In vivo experiments using po rcine skin determined the efficacy of solders augmented with growth fa ctors. Incisions were repaired using human albumin alone or supplement ed with HB-EGF (2 mu g), bFGF (10 mu g), or TGF-beta(1) (1 mu g). Woun ds were excised at 3, 5, and 7 days post-operatively. Tensile strength , total collagen content, and histology were performed. Results: At 3 days, tensile strength (TS) of TGF-beta(1) wounds were 36% (P < 0.05) and 20% (n.s.) stronger than laser alone and suture closures, respecti vely. By 5 days the TS of the TGF-beta(1) group increased by 50% (P < 0.05) and 59% (P < 0.02) over laser alone and suture groups, respectiv ely. At 7 days the TGF-beta(1) group was 50% (P < 0.05) and 79% (P < 0 .01) stronger than laser solder alone or suture, respectively. The HB- EGF and bFGF groups were equivalent to the laser solder group at all t ime points. Total collagen content at 7 days increased in the TGF-beta (1) group by 7% (n.s.) over the suture group and 21% (P < 0.05) in the laser group. Conclusion: Human albumin solder supplemented with TGF-b eta(1) increases the early post-operative strength of laser welded wou nds. This novel application of laser tissue soldering augmented with a growth factor has the potential to bring about immediate fluid tight seals while providing site specific delivery of biological modifiers. This may lead to an overall improvement in post-operative convalescenc e, wound infections, and hospital costs.