Evaluating the Effects of Injected Calcium Hydroxylapatite on Changes in Human Skin Elastin and Proteoglycan Formation

Previous studies have shown that calcium hydroxylapatite (CaHa) injected intradermally resulted in new collagen production at 6 months after injection, and a possible increase in elastin formation. In addition, a recent study showed the formation of new collagen, elastin, and angiogenesis after injection at 4 and 9 months.To evaluate any changes in the presence of elastic fibers, proteoglycans, and elastin in photodamaged skin after injections with CaHa.Fifteen subjects underwent a punch biopsy of the right infra-auricular areas before and after injection of CaHa on day 180. Specimens were stained for elastic fibers, elastin, and proteoglycan presence.Quantitative analysis demonstrated a percent change in elastic fibers varying between 29% and 179% at 6 months in comparison with baseline. Subjects showed an increase in elastin between 12% and 66%. Subjects had positive mean percentage change in proteoglycans of 76.27% (t-test of 0.198).This is the first study to show that CaHa can increase proteoglycans and echoed previous studies showing it can also have an effect on elastin, which indicates it can induce remodeling of all aspects of the extracellular matrix. Much larger and longer studies are required to confirm its unique impact on collagen, elastin, and proteoglycans.