Suction assisted liposuction does not impair the regenerative potential of adipose derived stem cells

Abstract

Background: Adipose-derived stem cells (ASCs) have been identified as a population of multipotent cells with promising applications in tissue engineering and regenerative medicine. ASCs are abundant in fat tissue, which can be safely harvested through the minimally invasive procedure of liposuction. However, there exist a variety of different harvesting methods, with unclear impact on ASC regenerative potential. The aim of this study was thus to compare the functionality of ASCs derived from the common technique of suction-assisted lipoaspiration (SAL) versus resection.

Methods: Human adipose tissue was obtained from paired abdominoplasty and SAL samples from three female donors, and was processed to isolate the stromal vascular fraction. Fluorescence-activated cell sorting was used to determine ASC yield, and cell viability was assayed. Adipogenic and osteogenic differentiation capacity were assessed in vitro using phenotypic staining and quantification of gene expression. Finally, ASCs were applied in an in vivo model of tissue repair to evaluate their regenerative potential.

Results: SAL specimens provided significantly fewer ASCs when compared to excised fat tissue, however, with equivalent viability. SAL-derived ASCs demonstrated greater expression of the adipogenic markers FABP-4 and LPL, although this did not result in a difference in adipogenic differentiation. There were no differences detected in osteogenic differentiation capacity as measured by alkaline phosphatase, mineralization or osteogenic gene expression. Both SAL- and resection-derived ASCs enhanced significantly cutaneous healing and vascularization in vivo, with no significant difference between the two groups.

Conclusion: SAL provides viable ASCs with full capacity for multi-lineage differentiation and tissue regeneration, and is an effective method of obtaining ASCs for cell-based therapies.

Fig. 1

ASCs are less frequent in SAL lipoaspirates than in resected adipose tissue but display comparable viability. a Flow cytometric analysis evaluating the frequency of CD45- cells (top row) and ASCs (CD45-/31-/34+ cells; bottom row) within the SVF from SAL lipoaspirates and excised adipose tissue. b Quantification of CD45-/31-/34+ ASCs in SAL and excised adipose tissue derived. c MTT assay demonstrating no significant difference regarding cellular viability. n = 3. All data are means ± one SEM. SAL suction-assisted liposuction

Fig. 2

SAL and excisional fat derived ASCs have equal osteogenic lineage differentiation capacities. a Representative images and quantification of Alkaline Phosphatase and b Alizarin Red staining following osteogenic differentiation of SAL and excisional fat derived ASCs. c RT-PCR quantifying the expression of early (RUNX2), and late (OCN) osteogenic markers in vitro. n = 3. All data are means ± one SEM. RUNX2 runt-related transcription factor 2, OCN osteocalcin

Fig. 3

SAL derived ASCs have similar adipogenic lineage differentiation capacities. a Representative images and quantification of Oil Red O staining following adipogenic differentiation of SAL and abdominoplasty derived ASCs. b RT-PCR quantifying the expression of adipogenic markers in vitro. Top PPAR-γ, middle FABP4, bottom LPL. n = 3. All data are means ± one SEM. PPAR-γ peroxisome proliferator-activated receptor γ, FABP4 fatty acid binding protein 4, LPL lipoprotein lipase

Fig. 4

Application of SAL and abdominoplasty derived ASCs are equalliy efficacious to enhance cutaneous healing. a Gross appearance, b wound healing kinetics, and c closing times of humanized excisional murine wounds treated with hydrogel seeded hASCs harvested via SAL, abdominoplasty or unseeded hydrogel. n = 8. Asterisk indicates p ≤ 0.05. All data are means ± one SEM

Fig. 5

Both ASC treatment groups display enhanced cutaneous wound vascularity. CD31 staining confirmed a significant increase in neovascularization among both ASC tretment groups. DAPI nuclear stain. Scale bar 100 μm. n = 8. Asterisk indicates p ≤ 0.05. All data are means ± one SEM