Liposuction aspirates (primarily saline solution, blood, and adipose tissue fragments) separate into fatty and fluid portions. Cells isolated from the fatty portion are termed processed lipoaspirate (PLA) cells and contain adipose-derived adherent stromal cells (ASCs). Here we define cells isolated from the fluid portion of liposuction aspirates as liposuction aspirate fluid (LAF) cells. Stromal vascular fractions (SVF) were isolated separately from both portions and characterized under cultured and non-cultured conditions. A comparable number of LAF and PLA cells were freshly isolated, but fewer LAF cells were adherent. CD34+ CD45- cells from fresh LAF isolates were expanded by adherent culture, suggesting that LAF cells contain ASCs. Although freshly isolated PLA and LAF cells have distinct cell surface marker profiles, adherent PLA and LAF cells have quite similar characteristics with regard to growth kinetics, morphology, capacity for differentiation, and surface marker profiles. After plating, both PLA and LAF cells showed significant increased expression of CD29, CD44, CD49d, CD73, CD90, CD105, and CD151 and decreased expression of CD31 and CD45. Multicolor FACS analysis revealed that SVF are composed of heterogeneous cell populations including blood-derived cells (CD45+), ASCs (CD31- CD34+ CD45- CD90+ CD105- CD146-), endothelial (progenitor) cells (CD31+ CD34+ CD45- CD90+ CD105low CD146+), pericytes (CD31- CD34- CD45- CD90+ CD105- CD146+), and other cells. After plating, ASCs showed a dramatic increase in CD105 expression. Although some adherent ASCs lost CD34 expression with increasing culture time, our culture method maintained CD34 expression in ASCs for at least 10-20 weeks. These results suggest that liposuction-derived cells may be useful and valuable for cell-based therapies.

Injective transfer of autologous aspirated fat is a popular option for soft tissue augmentation, but several issues require attention, including unpredictability and a low survival rate due to partial necrosis. In this study, histologic features and yield of adipose-derived stromal (stem) cells (ASCs) were compared between human aspirated fat and excised whole fat. Aspirated fat contained fewer large vascular structures, and ASC yield was lower in aspirated fat. Aspirated fat was transplanted subcutaneously into severe combined immunodeficiency mice with (cell-assisted lipotransfer; CAL) or without (non-CAL) vascular stromal fractions containing ASCs isolated from adipose tissue. The CAL fat survived better (35% larger on average) than non-CAL fat, and microvasculature was detected more prominently in CAL fat, especially in the outer layers. DiI-labeled vascular stromal fraction cells were found between adipocytes and in the connective tissue in CAL fat, and some of these cells were immunopositive for von Willebrand factor, suggesting differentiation into vascular endothelial cells. Another experiment that used vascular stromal fractions taken from green fluorescent protein rats also suggested that ASCs differentiated into vascular endothelial cells and contributed to neoangiogenesis in the acute phase of transplantation. These findings may partly explain why transplanted aspirated fat does not survive well and suggest clinical potential of the CAL method for soft tissue augmentation.

Wound fluids, human serum from platelet-poor and platelet-rich plasma (SPPP and SPRP), contain various soluble factors involved in cell growth and proliferation. Levels of cytokines, chemokines, and matrix metalloproteinases (MMPs) in drainage fluids (DFs) harvested from subcutaneous wounds, punctured fluids (PF) from seroma, and SPPP were measured. SPPP and SPRP from four healthy volunteers were also subjected to the analysis. Biochemical profiles of DF reflected the sequential stages of wound healing. Early-phase DF contained high concentrations of basic fibroblast growth factor and platelet-derived growth factor and EGF. The levels of keratinocyte growth factor, interleukin-6, and MMP-8 in DF peaked on days 2-3, while vascular endothelial growth factor, hepatocyte growth factor, interleukin-8, and MMP-1 increased over time during days 0-6. Punctured fluids contained high levels of TGF-beta1, keratinocyte growth factor, vascular endothelial growth factor, hepatocyte growth factor, and MMP-1. Experiments using human adipose-derived stem cells and dermal fibroblasts cultured in media containing various concentrations of DF and fetal bovine serum suggested that for some cell types, DF-contained growth factors that are not obtained from SPRP could be used to supplement or substitute for serum in culture media. SPRP and DF are economical ready-made mixtures of serum and autologous soluble factors, and may be differentially useful for regenerative therapies.

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Serum from platelet-rich plasma, which is less invasive to prepare than serum from whole blood, was superior to serum from platelet-poor plasma as a substitute for animal-derived serum in culture expansion of dermal fibroblasts. Although autologous or human-derived serum preparations may be of great use in cell-based therapies, this usefulness strongly depends on the target cell species and the purpose of the cell culture.