Background
Intraarticular treatment of knee osteoarthritis with adipose tissue-derived stem cells has shown promising results. Until now, standard processing of lipoaspirates for therapeutic use consists of enzymatic digestion (ED) and cell expansion prior to injection. However, complex regulatory issues related to the application of enzymatically treated and expanded cells have led to the development of microfragmentation (MF) to harvest stem cells ready for treatment.
Aim
To assess quantity and viability of stem cells from abdominal adipose tissue (AT) when processed with MF compared to ED.
Materials And Methods
Abdominal AT from knee osteoarthritis patients was processed with MF and ED, respectively. Cell type, quantity, and viability was investigated using flow cytometry and trypan blue staining. Statistical analysis was performed using paired t-tests. Normality of data was confirmed using Shapiro-Wilk tests and QQ-plots. p-values <0.05 were considered statistically significant.
Results
AT from 15 patients, age (mean (SD) 50.9 (8.5)), were analyzed. ED provided more nucleated cells 3.9x10^6/mL (2.5x10^6) than MF 1.0x10^6/mL (0.5x10^6), p<0.01. Also, ED gave higher nucleated cell viability 90% (4%) compared to MF 80% (6%), p<0.01. Using flow cytometric gating on stem cells, high viability was identified for ED 82% (4%) and MF 84% (3%) with no statistically significant difference, p=0.17. There was higher stem cell content per total nucleated cell count for MF 10% (2%) compared to ED 6% (2%), p<0.01. Adventitial stem cells (CD31-/CD45-/CD34+/CD146-), pericytes (CD31-/CD45-/CD34-/CD146+), mesenchymal stem cells (CD34-/CD45-/CD146-/CD90+/CD105+), and CD271+ stem cells (CD31-/CD45-/CD90+/CD271+) were identified in microfragmented AT.
Conclusion
Microfragmentation is a promising method to harvest clinically relevant stem cells from adipose tissue for the treatment of osteoarthritis.