Recombinant Humanized Type III Collagen Enhances Fat Graft Retention by Promoting Angiogenesis and Adipocyte...

Area of Science:

• Regenerative Medicine
• Biomaterials Science
• Tissue Engineering

Background:

• Autologous fat grafting (AFG) efficacy is often limited by inconsistent long-term fat graft retention.
• Type III collagen (Col III) is implicated in supporting crucial processes like angiogenesis, adipocyte survival, and immune modulation.

Purpose of the Study:

• To investigate the efficacy of recombinant humanized type III collagen (rhCol III) in enhancing fat graft survival.
• To determine if rhCol III improves fat graft retention in a concentration-dependent manner.

Main Methods:

• Human lipoaspirate was combined with varying concentrations of rhCol III (0, 2, 4, 8 mg/mL) or normal saline and grafted into mice.
• Post-grafting assessments included volume retention, histology, collagen deposition, adipocyte viability, and gene expression analysis (PPARG, CEBPA, VEGFA, FGF2).
• RNA sequencing and in vitro studies with human adipose-derived stem cells (ADSCs) were performed to elucidate rhCol III's molecular and cellular effects.

Main Results:

• rhCol III demonstrated reduced volume loss starting from week 2, with maximal retention observed at the 4 mg/mL concentration.
• Histological analysis revealed superior structural integrity of grafts treated with 4 mg/mL rhCol III.
• rhCol III significantly upregulated markers of adipogenesis (PPARG, CEBPA), vascularization (VEGFA, FGF2), and adipocyte/endothelial cell presence (Perilipin 1, CD31), with optimal effects at 4 mg/mL.
• In vitro, rhCol III enhanced ADSC proliferation, adhesion, migration, and adipogenesis, particularly at 4 mg/mL.

Conclusions:

• rhCol III effectively enhances fat graft retention by promoting angiogenesis, adipocyte viability, and beneficial immune remodeling.
• An optimal concentration of approximately 4 mg/mL rhCol III was identified for maximizing these effects.
• rhCol III presents significant potential as a biomaterial adjunct to improve the consistency and outcomes of autologous fat grafting procedures.