Advantage of the Presence of Living Dermal Fibroblasts within Restylane(R) for Soft Tissue Augmentation

ABSTRACT

For the correction of facial wrinkles and skin contour defects, commercially prepared nonanimal stabilized hyaluronic acid(Restylane(R)) is now widely used. Although this suspension has been shown to be relatively safe and convenient to administer, varying degrees of resorption have required repeated percutaneous injection. Therefore, this study was undertaken to evaluate the feasibility of Restylane(R) combined with cultured human dermal fibroblasts to enhance the persistence of the injected implant. For the experimental group, fibroblasts from the dermis of healthy adults were isolated and cultivated. Five hundred thousand fibroblasts suspended in 200mul of Dulbecco's phosphate buffered saline(DPBS) were then dispersed in 200mul of Restylane(R) to form a human fibroblast mixed Restylane(R) that measured 400mul in volume. For the control group, 200mul of DPBS without fibroblasts was mixed with 200mul of Restylane(R) These implants were injected subdermally into the back of athymic nude mice at six sites; control group into the left three sites and experimental group into the right three sites. Twelve nude mice were injected to form total of 36 injections per group. The nodular swellings that resulted from the injections were excised wide enough to include skin beyond the swelling points down to panniculus carnosus layer using 5 mm punches, and the weights were measured at 1, 2, 4, 8, 12, and 16 weeks after the injections. Histologic comparisons were also made to confirm the presence of human collagen in the fibroblast mixed Restylane(R) group using immunohistochemical study with anti-human collagen type I polyclonal antibody. The mean weight of the control group nodules decreased throughout the examination period. The mean weight at 16th week was 60% of the weight at first week. On the other hand, the mean weight of the experimental group nodules decreased over the first 2 weeks only. Beyond 2 weeks, there was no further significant weight change. The mean weight at 16th week was 91% of the weight measured at first week. Histologic examination of the control group taken at each examination period exhibited negative immunohistochemical staining for human collagen. That of experimental group exhibited positive staining after 2 weeks, indicating the presence of human collagen. These results indicated that Restylane(R) mixed with cultured human dermal fibroblasts could be successfully injected as living grafts for long-term retention of the implants.