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Succinate ‐dependent respiratory capacity is reduced in human coronary artery endothelial cells after cold incubation and rewarming
Author(s) -
Camara Amadou K.S.,
Stowe David F,
Gruenloh Stephanie K,
Heinen Andre,
Aldakkak Mohammed,
Medhora Meetha M
Publication year - 2006
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.20.5.a1165-b
Subject(s) - incubation , respiration , digitonin , respiratory system , biology , mitochondrion , ouabain , hypothermia , cellular respiration , biochemistry , chemistry , anatomy , membrane , physiology , organic chemistry , sodium
Endothelial cells are damaged by hypothermia, but the susceptible pathways remain unknown. We tested if cold storage of human coronary artery endothelial cells (HCAEC) alters mitochondrial respiration. HCAEC were grown at 37°C in EGM‐2 under 5% CO 2 ‐95% air and were harvested between passages 5–12. Cells were incubated for 4–6 h at either 37°C or 4°C. After incubation, cells either remained intact or were permeabilized with digitonin. Respiration (nmoles·min·10 −6 cells) was measured at 37°C after adding succinate (state 2) and either ADP (state 3) alone, or the uncoupler CCCP alone (state 3uc). In warm permeabilized HCAEC, succinate increased (state 2) respiration by 4.4±0.7, ADP (state 3) by 9.0±1.3 and CCCP (state 3uc) by 9.4±1.5; RCR (state 3/state 2) was 2.8±0.5 and UCR (state 3uc/state 2) was 3.2±0.5. After cold incubation, rewarming and permeabilization, respiration was reduced; state 2 was 1.3±0.4*; state 3 was 2.5±0.9* and state 3uc was 3.9±0.7* (* p<0.05 vs 37°C). RCR and UCR were unaltered. In non‐digitonin treated cells there were no drug –induced respiratory changes indicating intact cell membranes. Reductions in states 2, 3 and 3uc after cold incubation indicated reduced respiratory capacity, possibly due to mitochondrial stunning or demise. The lack of change in RCR and UCR after cold incubation indicates coupling between respiration and ADP phosphorylation was not affected. Supported by NIH 69996.