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.