Calcium Hydroxyapatite Biostimulators: A Comparative Study of Biological Response and Particle Morphology

Area of Science:

• Biomaterials Science
• Dermatology
• Cell Biology

Background:

• Injectable calcium hydroxyapatite (CaHA) materials are utilized as dermal biostimulators.
• In vitro models offer controlled environments for comparing cellular responses to different formulations.
• This study focuses on evaluating two commercial CaHA-based dermal fillers.

Purpose of the Study:

• To compare the effects of two CaHA-based materials on human dermal fibroblast metabolic activity.
• To assess the impact of these materials on extracellular matrix (ECM) gene expression (collagen and elastin).
• To analyze the microsphere morphology of the CaHA-based materials.

Main Methods:

• Primary human dermal fibroblasts were treated with two CaHA materials (Sample R and Sample S) at 10 mg/mL.
• Metabolic activity was measured using the MTT assay at various time points (24, 36, 48, 72 hours).
• Gene expression of type I collagen and elastin was quantified via RT-qPCR, and microsphere morphology was examined using scanning electron microscopy (SEM).

Main Results:

• Both CaHA materials significantly increased fibroblast metabolic activity compared to controls across all time points.
• Sample S exhibited higher metabolic activity at 48 and 72 hours.
• Both materials upregulated collagen and elastin gene expression, with Sample S showing a more pronounced effect. SEM revealed spherical microspheres with distinct surface topographies.

Conclusions:

• Both CaHA-based materials demonstrated biocompatibility and modulated fibroblast activity and ECM gene expression in vitro.
• Differences in microsphere surface characteristics may influence the observed biological responses.
• Further research with longer incubation and protein-level analysis is warranted to fully elucidate CaHA material behavior.