A 3-step Mechanical Digestion Method to Harvest Adipose-derived Stromal Vascular Fraction

Adipose stromal vascular fraction (SVF) isolation with enzymatic digestion is the gold standard, but is expensive, having practical and legal concerns. The alternative mechanical SVF isolation methods provide lower cell yields as they employ either centrifugation, emulsification, or digestion steps alone. We combined mechanical processing with buffer incubation and centrifugation steps into an isolation method called "mechanical digestion" and compared the cell yields with that of enzymatic digestion.

A total of 40-mL lipoaspirate was harvested from 35 women undergoing liposuction and was submitted to conventional enzymatic digestion for SVF isolation or mechanical digestion using a closed unit harnessing 3 ports with blades, followed by buffer incubation and centrifugation. Culture of the SVFs and flow cytometry were performed.

The SVF cell yield obtained by enzymatic digestion was significantly higher 3.38 × 10⁶/mL (±3.63; n = 35) than that obtained by mechanical digestion 1.34 × 10⁶/mL (±1.69; n = 35), P = 0.015. The average cell viability was 82.86% ± 10.68 after enzymatic digestion versus 85.86% ± 5.74 after mechanical digestion, which was not significant. Mechanical digested SVF expressed 2-fold higher stem cell surface markers compared with enzymatically digested SVF. Mechanical digestion was less time consuming, cost effective, and did not require a specific laboratory environment.

Mechanically digested SVF was comparable to enzymatically digested SVF in terms of stromal cell composition and viability. With mechanical digestion, we can isolate 30%-50% SVF cells of that isolated with enzymatic digestion. Further studies are warranted to determine the clinical outcomes.