Gene Analysis of Biostimulators: Poly-L-Lactic Acid Triggers Regeneration While Calcium Hydroxylapatite Induces Inflammation Upon Facial Injection.

Summary

In a randomized, 13-week, single-center comparative study with biopsies at baseline and day 90 (n=21), PLLA increased extracellular matrix-related gene signaling with less inflammation, indicating regenerative pathways, whereas CaHA upregulated pro-inflammatory genes with limited evidence of regeneration. Pathway analyses (STRING/Reactome) support differential mechanisms of action.

Key Findings

• Randomized comparative biopsies (baseline and day 90) revealed distinct transcriptomic signatures between PLLA and CaHA.
• PLLA increased extracellular matrix components and showed reduced inflammatory signaling consistent with regenerative pathways.
• CaHA upregulated pro-inflammatory genes and showed limited evidence of tissue regeneration in analyzed markers.

Clinical Implications

PLLA may be preferable when regenerative remodeling with lower inflammatory signaling is desired; CaHA use should consider potential for heightened inflammation and tailored aftercare.

Limitations

• Small sample size (n=21) and single-center design limit generalizability
• Surrogate molecular endpoints without long-term clinical outcome correlation

Future Directions

Validate findings in larger, multi-center cohorts, integrate proteomics/histomorphometry, and link molecular signatures to long-term clinical outcomes.