Improved Neocollagenesis and Skin Mechanical Properties After Injection of Diluted Calcium Hydroxylapatite in the Neck and Décolletage:A Pilot Study.

BACKGROUND: Calcium hydroxylapatite (CaHA; Radiesse (R)) provides safe and effective correction of moderate-to-deep lines, volume replacement, lift and contour, and induction of neocollagenesis and neoelastogenesis for improved skin quality. CaHA hyperdilution takes advantage of its skin-tightening properties without a volumizing effect. OBJECTIVE: To evaluate the collagen- and elastin-stimulating effects of diluted CaHA in subjects with skin laxity in the neck and décolletage. METHODS: Twenty subjects with skin laxity in the neck and décolletage received multiple, linear, subdermal injections of CaHA diluted with preserved saline at baseline and 4 months: 1:2 dilution (normal skin), 1:4 dilution (thin skin), and 1:6 dilution (atrophic skin). Subjects also received deep subdermal injection of CaHA (~0.1 ml) of the same dilution in the peri-auricular area for skin biopsy. Biopsy tissue was obtained at baseline, 4 months, and 7 months for immunohistochemical evaluation of neocollagenesis. Changes to skin mechanical properties were measured by ultrasound scanning and cutometry. Subject and investigator satisfaction was evaluated using the Global Aesthetic Improvement Scale. RESULTS: Immunohistochemical analysis of biopsy tissue demonstrated signi cant increases in collagen I expression at 4 months (P less than 0.05) and 7 months (P less than 0.00001) compared with baseline. Increases in collagen III levels were also significant at 4 months (P less than 0.00001); they declined by 7 months but remained above baseline. Staining for elastin and angiogenesis signi cantly increased at 4 months (P less than 0.05 and P less than 0.01, respectively) and 7 months (P less than 0.00001 for both) compared with baseline. Immunohistochemical data correlated with improvements in skin elasticity and pliability evaluated by cutometry, and with ultrasound-assessed increases in dermal thickness. Subject and investigator satisfaction was high, and the procedure was well tolerated. CONCLUSIONS: Injection of diluted CaHA is very effective for skin tightening of the neck and décolletage. J Drugs Dermatol. 2017;16(1):68-74..