Long-term efficacy of a novel ribose-cross-linked collagen dermal filler: a histologic and histomorphometric study in an animal model.

[BACKGROUND] Degradation and loss of the three-dimensional shape are the major causes of limited functional longevity of dermal fillers made of natural polymers as collagen and hyaluronic acid.

[OBJECTIVE] This study assessed the functional longevity of a new ribose-cross-linked collagen filler during 24 months in an animal model.

[METHODS] Ribose-cross-linked collagen (Evolence, Colbar Life Sciences Ltd), glutaraldehyde-cross-linked collagen (Zyplast, Inamed Inc.), and non-cross-linked collagen (Zyderm, Inamed Inc.) were injected in the rabbit ear dermis. Biopsies obtained at 1, 6, 12, and 24 months were histomorphometrically assessed for shape preservation and cell repopulation.

[RESULT] The three-dimensional shape of Evolence remained stable during 24 months. Zyderm and Zyplast lost their three-dimensional shape after 6 months. Although the cell density in Evolence remained stable over time, that in Zyplast and Zyderm decreased significantly at 12 and 24 months.

[CONCLUSION] Ribose-cross-linked collagen is endowed with a higher functional longevity as assessed in an animal model when compared with the most used collagen-based dermal fillers.