Cytogenetic evaluation of human endothelial cell cultures

Abstract

Cytogenetic evaluation of serially subcultivated human endothelial cells revealed significant differences between cultures derived from fetal umbilical cords and cultures derived from various vessel sites in adults. A rapid increase in the prevalence of polyploid cells, to levels of 100% in many cases, was detected in human umbilical vein endothelial cell cultures but not in endothelial cell cultures from adult vessels. Because the development of polyploidy has been viewed as one signpost of in vitro senescence, it may be that these in vitro observations of high levels of polyploidy are a reflection of the fact that umbilical tissue is at the end of its in vivo developmental lifespan when studied. Consistent karyotypic alterations also were observed in two clones from adult human abdominal aorta, even though these cultures exhibited low percentages of polyploid cells. Cultures of one clone exhibited a trisomy of chromosome 11, on which there are at least three onc gene loci, and a deletion of chromosome 13 through band q14. A loss of band 13q14 is a prezygotic chromosomal lesion known to predispose to retinoblastoma. In the other clone, two cell populations were observed, and each displayed a chromosomal abnormality. A trisomy of the long arm of chromosome 2 was noted in one cell population via a marker chromosome involving 2 and 14. The other cell population exhibited an abnormality of chromosome 2. Neither of these karyotypic alterations was detected in the parent culture from which the clones were derived. The results reported in this study have both practical and theoretical implications. The high incidence of polyploidy in serially cultivated umbilical cultures as well as the occurrence of chromosomal changes in umbilical and aortic cultures testify to the need for cytogenetic monitoring of cell cultures even though they are derived from presumably normal tissue. Cytogenetic changes in the endothelium may be important in atherogenesis and other pathologic states. The conversion of diploid endothelial cells into polyploid endothelial cells may provide a convenient model cell system for studying mechanisms of the development of polyploidy in cells and their relationship to in vitro senescence.

Karyotypic and phenotypic changes during in vitro aging of human endothelial cells

“…Perhaps the trisomy 11 can act in concert with several other trisomies, or the other trisomies result from a general process that randomly increases the frequency of nondisjunction. Nichols et al (1987) found high levels ofpolyploidy in cell lines derived from umbilical cords (loo%), but only a moderate increase in the adult cell lines. Perhaps because of improved techniques in isolation and culturing (Levine, unpublished data), our adult endothelial lines appear t o proliferate longer in culture and undergo more CPDLs than those studied by Nichols et al (1987).…”

“…Nichols et al (1987) found high levels ofpolyploidy in cell lines derived from umbilical cords (loo%), but only a moderate increase in the adult cell lines. Perhaps because of improved techniques in isolation and culturing (Levine, unpublished data), our adult endothelial lines appear t o proliferate longer in culture and undergo more CPDLs than those studied by Nichols et al (1987). This may account for the higher levels of polyploidy in some of the adult EC cultures analyzed and the increased frequency of trisomy 11 seen in the current study.…”

Are human cancers ever diploid—or often trisomic? Conflicting evidence from direct preparations and cultures

“…However, trisomic clones may also arise in cultures of cells from individuals without cancer. Nichols et al (1987) found tri somy 11, as well as a deletion of 13q, in a culture of endothelial cells from the abdominal aorta. The latter observation clearly shows that caution should-be exercised in the interpretation of chro mosome changes in cultures derived from tumor tissue.…”

Survival advantage of cultured human vascular endothelial cells that lost chromosome 13

“…Chromosome 13 monosomy is associated with LOH, and an increase in migratory and presumably proliferative capacity-a phenomenon suggesting clonal expansion and survival advantage under HUVEC culture conditions. Aneuploidy has been observed by others (Nichols et al 1987;Johnson et al 1992) and us (Zhang et al 2000) in cultured VECs from human donors. However, other studies found that the common feature of aneuploidy in cells derived from different donors was the development of polyploidy in late passages (Saksela and Moorhead 1963;Benn 1976).…”

“…Aneuploidy, i.e., the state of loss or gain of chromosomes, is frequently observed in cultured human cells, including human vascular endothelial cells (VECs) (Saksela and Moorhead 1963;Benn 1976;Nichols et al 1987;Casalone et al 1992;Johnson et al 1992;Kehrer et al 1994;Mukherjee and Costello 1998). However, this phenomenon is primarily observed in presenescent cultured cells.…”