Age-dependent injury in human umbilical vein endothelial cells: relationship to apoptosis and correlation with a lack of A20 expression.
BACKGROUND
It has recently been shown that human umbilical vein endothelial cells (HUVEC) become increasingly sensitive to growth factor deprivation, resulting in cell death, as a function of age in culture. The overall goal of the present study was to investigate the mechanism of lethal injury in these cells and compare the injury process to other known mechanisms of injury in the same cells.


METHODS
HUVEC were established in culture and maintained for four passages. Injury to first-passage cells and fourth-passage cells were examined for injury in the presence of agents that are known to confer resistance to apoptosis. Ultrastructural features of injury and DNA fragmentation patterns were assessed. Expression of factors that are known to be associated with resistance to apoptosis in other models were assessed.


RESULTS
Fourth-passage HUVEC undergoing injury exhibited morphologic features characteristic of apoptosis and DNA fragmentation. Agents known to inhibit apoptotic cell injury in other models inhibited injury. A20 expression was correlated with resistance to injury in fourth-passage HUVEC, but there was no correlation between bcl-2 and bcl-x expression and resistance to injury.


CONCLUSIONS
HUVEC injury resulting from growth factor deprivation increases as a function of age in vitro and appears to be a form of apoptosis. A20 expression may confer resistance to cell injury through this pathway.
Varani
J
J
Department of Pathology, University of Michigan Medical School, Ann Arbor, USA.
Dame
M K
MK
Taylor
C G
CG
Sarma
V
V
Merino
R
R
Kunkel
R G
RG
Nunez
G
G
Dixit
V M
VM
D017209:Apoptosis; D002478:Cells, Cultured; D016922:Cellular Senescence; D004249:DNA Damage; D004268:DNA-Binding Proteins; D004730:Endothelium, Vascular / Q000737:chemistry / Q000473:pathology*; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D009687:Nuclear Proteins; D011506:Proteins / Q000032:analysis*; D011518:Proto-Oncogene Proteins / Q000032:analysis; D019253:Proto-Oncogene Proteins c-bcl-2; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D000072598:Tumor Necrosis Factor alpha-Induced Protein 3; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology; D014471:Umbilical Veins / Q000737:chemistry / Q000473:pathology*; D016335:Zinc Fingers
D004268:DNA-Binding Proteins; D047908:Intracellular Signaling Peptides and Proteins; D009687:Nuclear Proteins; D011506:Proteins; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D014409:Tumor Necrosis Factor-alpha; C076529:TNFAIP3 protein, human; D000072598:Tumor Necrosis Factor alpha-Induced Protein 3; D013755:Tetradecanoylphorbol Acetate