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ABSTRACT: Gadolinium-containing magnetic resonance imaging (MRI) contrast agents such as Omniscan are associated with nephrogenic systemic fibrosis (NSF). To determine if Omniscan can affect the differentiation of monocytes into fibroblast-like cells called fibrocytes that are found in the fibrotic lesions of NSF, peripheral blood mononuclear cells (PBMCs) from NSF patients, hemodialysis patients without NSF, and healthy, renally sufficient controls were exposed to Omniscan in a standardized in vitro fibrocyte differentiation protocol. When added to PBMCs, the gadolinium-containing MRI contrast agent Omniscan generally had little effect on fibrocyte differentiation. However, 10(-8) to 10(-3) mg/mL Omniscan reduced the ability of the fibrocyte differentiation inhibitor serum amyloid P (SAP) to decrease fibrocyte differentiation in PBMCs from 15 of 17 healthy controls and one of three NSF patients. Omniscan reduced the ability of SAP to decrease fibrocyte differentiation from purified monocytes, indicating that the Omniscan effect does not require the presence of other cells (such as T cells) in the PBMCs. Omniscan also reduced the ability of a different fibrocyte differentiation inhibitor, interleukin-12, to decrease fibrocyte differentiation. These data suggest that Omniscan interferes with the regulatory action of signals that inhibit the differentiation of monocytes to fibrocytes. J. Magn. Reson. Imaging 2009;30:1284-1288. (c) 2009 Wiley-Liss, Inc.
Journal of Magnetic Resonance Imaging 12/2009; 30(6):1284-8. · 2.70 Impact Factor
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ABSTRACT: CD14+ peripheral blood monocytes can differentiate into fibroblast-like cells called fibrocytes. Fibrocytes are associated with, and are at least partially responsible for, wound healing and fibrosis in multiple organ systems. In a variety of lesions in vivo, monocytes appear to differentiate into fibrocytes within days. However, in vitro culture conditions can take up to two weeks to generate fibrocytes. In this study, we describe enhanced serum-free conditions that support the rapid differentiation of human and murine fibrocytes. We compared the effect on fibrocyte differentiation of different anti-coagulants used when collecting blood, and for culturing cells, the effects of different commercial media formulations, the addition of a variety of supplements, cell density, conditioned medium, and glass and plastic substrates. We found that both heparin and EDTA were suitable anti-coagulants, but that blood treated with citrate-phosphate dextrose led to a reduced number of fibrocytes. Fibrocyte differentiation was enhanced when the serum-free medium was based on either FibroLife or StemPro formulations. We also found that only positively charged or hydrophilic glass and plastic surfaces provide adequate support for fibrocyte differentiation. Finally, the optimal cell density was 2.5 x 10(5)cells/ml (approximately 800 cells per mm(2)). These results indicate that blood collection, substrates, media, and cell density all influence in vitro fibrocyte differentiation.
Journal of immunological methods 10/2009; 351(1-2):62-70. · 2.35 Impact Factor
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ABSTRACT: CD14+ peripheral blood monocytes can differentiate into fibroblast-like cells called fibrocytes, which are associated with and are at least partially responsible for wound healing and fibrosis in multiple organ systems. Signals regulating fibrocyte differentiation are poorly understood. In this study, we find that when added to human PBMCs cultured in serum-free medium, the profibrotic cytokines IL-4 and IL-13 promote fibrocyte differentiation without inducing fibrocyte or fibrocyte precursor proliferation. We also find that the potent, antifibrotic cytokines IFN-gamma and IL-12 inhibit fibrocyte differentiation. In our culture system, IL-1beta, IL-3, IL-6, IL-7, IL-16, GM-CSF, M-CSF, fetal liver tyrosine kinase 3, insulin growth factor 1, vascular endothelial growth factor, and TNF-alpha had no significant effect on fibrocyte differentiation. IL-4, IL-13, and IFN-gamma act directly on monocytes to regulate fibrocyte differentiation, and IL-12 acts indirectly, possibly through CD16-positive NK cells. We previously identified the plasma protein serum amyloid P (SAP) as a potent inhibitor of fibrocyte differentiation. When added together, the fibrocyte-inhibitory activity of SAP dominates the profibrocyte activities of IL-4 and IL-13. The profibrocyte activities of IL-4 and IL-13 and the fibrocyte-inhibitory activities of IFN-gamma and IL-12 counteract each other in a concentration-dependent manner. These results indicate that the complex mix of cytokines and plasma proteins present in inflammatory lesions, wounds, and fibrosis will influence fibrocyte differentiation.
Journal of Leukocyte Biology 07/2008; 83(6):1323-33. · 4.99 Impact Factor
