We studied the ability of human umbilical vein endothelial cells to recover from oxidant-induced ATP depletion. When endothelial cell ATP levels were depressed to 0.93 ± 0.14 pmol/μg protein (compared with 4.96 ± 0.6 pmol/μg protein in control cells) by hydrogen peroxide generated with 25 mU/ml glucose-glucose oxidase over 45 minutes, ATP levels returned to 1.73 ± 0.21 pmol/μg protein during a 3-hour recovery period after oxidant injury ceased. When 25 μM ATP, ADP, AMP, or adenosine was added to the recovery media, intracellular ATP was significantly (p < 0.001) increased to greater than 4.4 pmol/μg cell protein for each metabolite. HPLC of supematants from oxidantinjured endothelial cells incubated with ATP, ADP, and AMP demonstrated extracellular metabolism of the adenine nucieotides to adenosine. When adenosine transport was inhibited with dlpyrldamole and nitrobenzylthioinosine, recovery of intracellular ATP by exogenous ATP, ADP, AMP, and adenosine was significantly (p < 0.001) inhibited. Such cells were Intact, as demonstrated by lack of LDH release. When oxidant stress was prolonged to 90 minutes, ATP depletion was irreversible, regardless of exogenously supplied adenosine; such cells demonstrated loss of cell integrity as demonstrated by release of intracellular LDH. Our results demonstrated that exogenous adenine nucleotides enhance recovery of oxidant-induced ATP depletion through metabolism to adenosine and subsequent adenosine uptake. Prolonged oxidant injury resulted in irreversible ATP depietion and loss of cell integrity that was not altered by exogenously supplied adenosine.
|Original language||English (US)|
|Number of pages||10|
|Journal||The Journal of Laboratory and Clinical Medicine|
|State||Published - Mar 1990|
ASJC Scopus subject areas
- Pathology and Forensic Medicine