Mitogenic factors present in serum but not in plasma.

Abstract

In culture medium containing heparinized, heatinactivated, chicken plasma, normal chicken heart mesenchymal cells do not proliferate but their Rous sarcoma virus-infected counterparts proliferate maximally. In medium containing serum derived from chicken whole blood or plasma, on the other hand, normal chicken heart mesenchymal cells proliferate actively, at similar overall rates and to similar extents. The rate and extent of normal cell proliferation are decreased by a factor of approximately 'A with whole blood-derived serum that is heparinized and inactivated; proliferation ceases in plasma-derived serum that is heparinized and inactivated. Heparinization and inactivation of serum does not affect the proliferation of Rous sarcoma virus-infected cells, indicating that this combined treatment eliminates a mitogenic (regulatory) rather than a supportive (nutrient) factor(s) for cell replication. We hypothesize that mitogen(s) is released from plasma protein precursors when plasma clots in the presence of formed elements of the blood or when plasma-derived serum is exposed to cultured cells; heparinization and inactivation, within the framework of this hypothesis, would render nonfunctional the plasma protein precursor(s) from which the mitogen(s) is generated. Alternatively, our data are consistent with the release of two mitogens during blood clotting, one from plasma protein precursors and the other from formed elements of the blood. We also have studied the proliferative behavior of Swiss and BALB/c 3T3 cells in whole blood-derived and plasma-derived human serum. Our studies suggest that the platelet-derived growth factor has an artifactual supportive (nutrient) role, rather than an authentic mitogenic role, in cell replication.Between 1971 and 1973, Balk and coworkers (1-3) demonstrated that normal chicken pectoral muscle fibroblasts did not proliferate in low-calcium culture medium containing chicken plasma but proliferated actively when this medium contained chicken serum. On the basis of that observation, it was postulated that a mitogen might be released from plasma protein precursors or from formed elements of the blood during the clotting process and that this mitogen, found in serum but not in plasma, might represent a "wound hormone" capable of initiating cell proliferation at sites of tissue injury. Because of uncertainties inherent in the interpretation of data derived from studies using a culture medium with a low calcium concentration (4), however, further studies of the serum-plasma difference were deferred until a culture system was available in which normal cells were quiescent in a plasma-containing medium with physiological ion concentrations.Other workers subsequently have claimed that the mitogenic property present in serum, but not plasma, resided in a specific polypeptide "platelet-derived growth factor" (for general re-views, see refs. 5 and 6; for critical reviews, see refs. 7 and 8). Ross and Vogel (5) Because the activity ofthe platelet-derived growth factor has been defin...

Serum-free cell culture: the serum-free media interactive online database

“…this appears to be due to the release of certain polypeptides from activated platelets during the clotting process (Balk et al, 1981;Gospodarowicz and Ill, 1980).…”

Alternatives to the use of fetal bovine serum: human platelet lysates as a serum substitute in cell culture media

“…In the past, much effort was spent to identify the factors in serum that stimulate cell growth in vitro. An important step forward in the search for serum growth factors has been the finding that the most potent mitogenic factors present in serum are derived from activated thrombocytes (Balk et al, 1981;Gospodarowicz and Ill, 1980). Platelets are known to be a rich source of growth factors (Marx et al, 1998;Weibrich et al, 2002;Anitua et al, 2004), thus suggesting platelet lysates as a valuable animal serum substitute.…”

Characterization of Human AB Serum for Mesenchymal Stromal Cell Expansion

“…However, the amount of autologous serum is limited, and a large part of it is needed for clinical applications. It has been suggested that the natural coagulated serum is more effective than plasma for cell proliferation due to the release of certain polypeptides and growth factors from activated platelets during the coagulation process [24,25]. Nevertheless, neither fresh serum nor natural coagulated serum are common and broadly available blood bank-derived products.…”