Yield of human adipose-derived adult stem cells from liposuction aspirates

BACKGROUND

Primary cultures of isolated human adipose-derived adult stem (ADAS) cells are multipotent and differentiate in vitro along the adipocyte, chondrocyte, neuronal, osteoblast, and skeletal muscle pathways.

METHODS

We examined the ADAS cell yield per unit volume of liposuction tissue, and their surface protein phenotype by flow cytometry. Adipogenesis was assessed by Oil Red O staining and ELISA analysis of leptin secretion.

RESULTS

The donor population was 87.5% female (n=18) with a mean age (+/-SD) of 44+/-10 years and body mass index (BMI) of 24.9+/-2.7. The mean cell yield was 404 000+/-206 000 cells per milliliter of lipoaspirate (n=18). Linear regression analysis of the cells derived from the female donors demonstrated a significant negative correlation between the number of cells obtained per milliliter of lipoaspirate with the BMI but not the age of the donor. The undifferentiated ADAS cells were homogeneously positive for the cell-surface markers CD10, CD13, CD29, CD44, CD49e, CD59, CD90, and HLA-ABC, and homogeneously negative for the cell surface markers CD11b, CD45, and HLA-DR. The absence of the panhematopoietic marker, CD45, indicates that the ADAS cells do not derive from circulating BM hematopoietic stem cells. Adipocyte differentiation led to a 5.1-fold increase in Oil Red O staining, and a 196-fold increase in leptin secretion levels. Culture of the cells in the presence of antibiotic and fungizone did not alter the undifferentiated ADAS cell immunophenotype based on flow cytometry, or their adipocyte differentiation based on leptin secretion.

DISCUSSION

The ability to isolate a consistently homogeneous population of undifferentiated adult stem cells from adipose tissue of multiple donors supports their potential utility in future tissue-engineering applications.

Reduction in atherosclerotic lesion size in pigs by alphaVbeta3 inhibitors is associated with inhibition of insulin-like growth factor-I-mediated signaling

Insulin-like growth factor-I (IGF-I) is a potent stimulant of smooth muscle cell (SMC) migration and proliferation and has been implicated in the development of experimental atherosclerotic lesions. Because optimal stimulation of SMC in vitro by IGF-I requires ligand occupancy of alphaVbeta3, these studies were conducted to determine whether alphaVbeta3 antagonists would result in a change in lesion size and whether they could alter IGF-I-mediated actions. Clamps were placed on the carotid and femoral arteries of normal pigs that had been fed a high-cholesterol diet for 4 weeks. alphaVbeta3 inhibitors (SC-69000, SC-65811) (10(-6) mol/L) or saline were infused for 2 weeks into the peristenotic area. Lesion area, the number of SMC layers, and proliferating cell nuclear antigen positive cells were determined in a 1.2-mm segment of each artery. Lesion areas were 304 788+/-113 453 micron(2) (saline), compared with 149 799+/-35 456 micron(2) (SC-69000) (P<0.01). Lesion areas in arteries treated with SC-64258, a compound that does not bind to alphaVbeta3, were 310 284+/-160 467 micron(2), P=not significant. In a second experiment, lesion areas were 110 391+/-17 347 micron(2) (saline) and 59 533+/-17 568 micron(2) (SC-65811, P<0.001). Neointimal SMC layers were reduced by SC-65811 from 7.4+/-4.5 to 3.0+/-0.4 (P<0.001). To determine whether IGF-I action was altered, IGF binding protein-5, which is synthesized in response to IGF-I, was analyzed. IGF-I binding protein-5 mRNA abundance was reduced by 67+/-8% in the 6 lesions treated with SRL-69000 compared with saline controls (P<0.001). We conclude that alphaVbeta3 antagonists block the development of lesions in pigs that have been induced by a high-cholesterol diet and stenosis, and the effect of these compounds is associated with their ability to inhibit IGF-I-mediated signaling.

von Willebrand factor does not influence atherogenesis in arteries subjected to altered shear stress

The role of von Willebrand factor (vWF) in arterial neointimal formation that develops in arteries with altered shear stress was investigated using normal, heterozygous, and homozygous von Willebrand disease pigs (ie, vWD, or lacking vWF) that were fed normal pig chow. Shear stress was applied to carotid and femoral arteries with a Goldblatt clamp for 14 days, producing a > or = 80% stenosis. Neointimal lesion size was measured by computer-assisted morphometry. Expression of proliferative cell nuclear antigen (PCNA) by neointimial and medial cells was used as a relative index of proliferative activity. For shear-stressed arteries, there was no significant difference in the number of smooth muscle cell layers in the lesion, lesion size, and percent of PCNA-positive neointimal or medial cells among normal, heterozygous, and homozygous vWD pigs (P> or =.1, ANOVA). Lesions in pigs that expressed vWF (normals and heterozygotes) contained large amounts of vWF in the neointima, whereas lesions in vWD pigs had no detectable vWF. Moreover, no foam cells were detected in the lesions. Thus, the absence of vWF apparently does not alter the size of lesions in shear-stressed arteries in vWD pigs or the number of neointimal or medial cells expressing PCNA. Mechanism(s) involved with shear-induced modulation of smooth muscle cell proliferation, then, can operate independently of vWF in normolipemic pigs.