Viability, Yield and Expansion Capability of Feline MSCs Obtained from Subcutaneous and Reproductive Organ Adipose Depots

Abstract

Background: The source of multipotent stromal cells (MSC) can have a significant influence on the health and expansion capacity of the cells. As the applications for allogeneic MSCs in the treatment of feline diseases increase, the location of the initial donor tissue must be analyzed. To date, comparisons have only been made between feline MSCs collected from bone marrow or abdominal fat. This is the first report to compare cells obtained from different adipose depots in the cat. The adipose tissue was collected from 32 healthy cats undergoing spaying (fat around the ovaries and uterine horn) or subcutaneous fat collected during surgical procedures. Results: The total tissue yield from the subcutaneous fat was significantly greater than could be obtained from around the reproductive organs, leading to 3 times more total MSCs. However, the density of MSCs obtained from reproductive fat was significantly higher than from subcutaneous fat. In addition, the viability of the MSCs from the reproductive fat was significantly higher than the subcutaneous fat. When sufficient tissue was collected, it was digested either mechanically or enzymatically. Mechanical digestion further decreased the viability and yield of MSCs from subcutaneous fat compared to enzymatic digestion. Biomarkers of stem cell expansion and function were detected using qPCR. Gata6 was detected in all samples similarly regardless of site of harvest or method of digestion. Sox2 and Sox17 were also detected in all samples with higher quantities found in the enzymatically digested subcutaneous fat. Control genes of Gata4 and Pdx1 were detected in very low levels. Negative controls showed no detection prior to 50 cycles. During the first passage there was no statistically significant difference in doubling times or viability. But at P2, MSCs from the enzymatically-digested reproductive fat had the lowest doubling time and a trend towards the highest viability. Conclusion: Feline reproductive adipose tissue is a reasonable source of MSCs for eventual therapeutic applications with superior cell density, viability and expansion