Conclusion
These preliminary observations suggest that irradiated ADSCs close to the surgical site undergo long-term changes in proliferative capacity. The potential for phenotypic differentiation is retained, however, in ADSCs that survive the irradiation process. Level of evidence: 2b.
Methods
After institutional review board approval, 12 patients with a history of head and neck radiation and pending surgery were enrolled. Adipose tissue was collected from irradiated tissue (XRT) and nonirradiated tissue (NRT) sites. Mesenchymal stem cells were isolated from these populations, with subsequent assessment of cellular kinetics and differentiation potential between harvest sites.
Results
Adipose-derived stromal/stem cells could not be isolated from XRT in six patients due to lack of in vitro cell proliferation. For the remaining six patients, overall cumulative population-doubling time was longer for XRT relative to NRT (29.3 vs. 11.5 days; P = 0.02). However, no significant differences were observed in cell generation time or viability. When XRT and NRT ADSC fractions were grown to standardized concentrations and incubated under conditions that induce phenotypic differentiation of resident stem cells, no significant changes in chondrogenic, adipogenic, or osteogenic differentiation were observed.