TY - JOUR
T1 - Decreased blood oxygen diffusion in hypercholesterolemia
AU - Menchaca, Hector J.
AU - Michalek, Van N.
AU - Rohde, Thomas D.
AU - O'Dea, Thomas J.
AU - Buchwald, Henry
PY - 1998
Y1 - 1998
N2 - Background. Improvement of angina pectoris symptoms after cholesterol lowering has raised questions as to the underlying mechanisms. Methods. Rabbit experiment: We compared arterial blood samples from New Zealand White cholesterol supplemented rabbits (n = 6) with nonsupplemented rabbit samples (n = 4) in a closed-loop circulation diffusion system. The pH and partial pressures of oxygen (pO2) and carbon dioxide (pCO2) were measured continuously. The samples were first oxygen (O2) saturated (pO2, 160 mm Hg; pCO2, 4 mm Hg) and then desaturated in 100% nitrogen. Cholesterol levels were determined in whole blood, plasma (P Chol), red blood cells (RBCs), and RBC membranes. Human experiment: We exposed quadruple desaturated venous blood samples (n = 4) with P Chol levels of 87 to 400 mg/dL in a gas exchanger to capillary gas conditions (pO2, 23 mm Hg; pCO2, 46 mm Hg). After 15 minutes we performed blood gas analyses and compared our results to baseline values. Results. In the rabbit experiment the cholesterol- supplemented group as compared to the control group showed higher plasma pO2 levels during the saturation phase and lower plasma pO2 levels during the desaturation phase. It also had a markedly increased RBC membrane cholesterol content: 121 ± 3 (standard error of the mean [SEM]) mg/dL versus 22 ± 1.7 mg/dL in the control group (P < .05). This barrier to RBC membrane O2 diffusion caused delayed O2 entry into the RBCs during saturation, with a higher plasma pO2, and delayed O2 release from the RBCs during desaturation, with a lower plasma pO2. In the human experiment the P Chol level was inversely correlated with the percentage change of O2 content in milliliters of O2 per deciliter of blood (P <.05). Conclusions. Increased RBC membrane cholesterol in hypercholesterolemia appears to decrease the trans membrane O2 diffusion rate.
AB - Background. Improvement of angina pectoris symptoms after cholesterol lowering has raised questions as to the underlying mechanisms. Methods. Rabbit experiment: We compared arterial blood samples from New Zealand White cholesterol supplemented rabbits (n = 6) with nonsupplemented rabbit samples (n = 4) in a closed-loop circulation diffusion system. The pH and partial pressures of oxygen (pO2) and carbon dioxide (pCO2) were measured continuously. The samples were first oxygen (O2) saturated (pO2, 160 mm Hg; pCO2, 4 mm Hg) and then desaturated in 100% nitrogen. Cholesterol levels were determined in whole blood, plasma (P Chol), red blood cells (RBCs), and RBC membranes. Human experiment: We exposed quadruple desaturated venous blood samples (n = 4) with P Chol levels of 87 to 400 mg/dL in a gas exchanger to capillary gas conditions (pO2, 23 mm Hg; pCO2, 46 mm Hg). After 15 minutes we performed blood gas analyses and compared our results to baseline values. Results. In the rabbit experiment the cholesterol- supplemented group as compared to the control group showed higher plasma pO2 levels during the saturation phase and lower plasma pO2 levels during the desaturation phase. It also had a markedly increased RBC membrane cholesterol content: 121 ± 3 (standard error of the mean [SEM]) mg/dL versus 22 ± 1.7 mg/dL in the control group (P < .05). This barrier to RBC membrane O2 diffusion caused delayed O2 entry into the RBCs during saturation, with a higher plasma pO2, and delayed O2 release from the RBCs during desaturation, with a lower plasma pO2. In the human experiment the P Chol level was inversely correlated with the percentage change of O2 content in milliliters of O2 per deciliter of blood (P <.05). Conclusions. Increased RBC membrane cholesterol in hypercholesterolemia appears to decrease the trans membrane O2 diffusion rate.
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U2 - 10.1067/msy.1998.90944
DO - 10.1067/msy.1998.90944
M3 - Article
C2 - 9780990
AN - SCOPUS:0031662822
SN - 0039-6060
VL - 124
SP - 692
EP - 698
JO - Surgery
JF - Surgery
IS - 4
ER -