Preclinical graft study supports Cytori’s proposed mechanism of action

Dec 14 2009

Cytori Therapeutics (NASDAQ: CYTX) reported results from a preclinical cell-enriched fat grafting study supporting the safety and efficacy of Cytori’s method for enriching fat grafts with adipose-derived regenerative cells (ADRCs).

The study tracked the expression of important growth factors within the cell-enriched fat grafts and examined the time course of the effect of ADRCs in a transplanted graft and the temporal role of growth factor expression. The results were presented today at the 32^nd Annual CTRC-AACR San Antonio Breast Cancer Symposium (Poster #4124).

The study results demonstrate that the ADRCs used to enrich the fat grafts were active for several days after implantation and secreted several growth factors within the fat grafts. Gene expression for the specific growth factors associated with the restoration and repair of blood vessels was initially very high but subsided to undetectable levels after three weeks.

The results suggest that the efficacy of the ADRCs may be due in part to their ability to secrete multiple important growth factors locally within the graft. In addition, the subsequent down regulation of these growth factors has positive long-term safety implications since continued, high level expression of these growth factors may not be desirable. Overall, the initial local secretion of growth factors by ADRCs, followed by the rapid reduction in growth factor levels supports Cytori’s proposed mechanism of action, i.e. the transplanted cells swiftly impart regenerative benefit and then become quiescent.

According to the study design, mice were injected with a graft of mouse fat mixed with human ADRCs that were isolated using Cytori’s Celution® 800/CRS System. Samples of the ADRC enriched grafts were harvested at seven different time points over a period of 84 days. The samples were tested for the presence of human DNA and RNA, which can be used to detect key human specific growth factors, IGF-1 and VEGF-A.

Over the course of the study, the presence of human DNA was shown to decrease rapidly, with only 1% to be detected by day 14. No human DNA could be detected after day 56. Levels of IGF-1 and VEGF-A, as indicated by the presence of human RNA, also decreased, with neither detected after day 28.

Source: Cytori.