A modified technique for mechanical isolation of stromal vascular fraction yields increased final product volume and high viable nucleated cells count

Abstract

Purpose

Purpose of the present study is to report a modified protocol for stromal vascular fraction (SVF) isolation from abdominal fat, analyse its cellular composition and gene expression profile, and verify the safety and feasibility of the harvesting-preparation technique and subsequent intra-articular knee injection.

Methods

The SVF was obtained after mechanical dissociation of the autologous harvested adipose tissue. It was combined with autologous platelet-rich plasma and subsequently intra-articularly injected into both knees of patients with osteoarthritis. Part of the SVF solution was used to analyse its cellular composition via flow cytometry and its gene expression profile via real-time polymerase chain reaction. Any postinjection complications were documented.

Results

Twenty-three patients (10 female; 62.4 ± 8.4 years old) were enrolled. Posttreatment adverse events were mild and spontaneously resolved. Patients needed 3.7 ± 1.3 days for their knee to feel the same as before the injection. No patient provided less than 60 mL of lipoaspirate. Per 1 mL of SVF the total amount of viable nucleated cells was 49.7 ± 22.9 × 10⁶ on average, including 44.5 ± 23.2 × 10⁶ CD90+/CD105+ adipose-derived stem cells, 0.54 ± 0.18 × 10⁶ hematopoietic stem cells, 2.71 ± 1.18 × 10⁶ pericytes and 1.88 ± 0.64 × 10⁶ endothelial cells. The polymerase chain reaction analysis revealed the following average values: Transforming growth factor beta 7.94 ± 3.31; vascular endothelial growth factor 12.43 ± 5.20; interleukin-10 7.54 ± 2.88; octamer-binding transcription factor 3/4 2.65 ± 1.69; interleukin-1 beta 5.45 ± 3.27 and ki-67 6.01 ± 3.65.

Conclusion

A modification of an existing mechanical SVF preparation technique was introduced. The technique was feasible, safe and yielded a substantial volume of SVF (2.5–5 mL). The SVF obtained had a high cellular composition. Age, gender and body mass index (BMI) did not affect the cell count, but elder patients presented a decreased composition in cytokines and growth factors.

Level of Evidence

Level V.