Association between the angiotensin-converting enzyme gene polymorphisms and tissue oxygenation during exercise in patients with COPD.
OBJECTIVE
We have recently determined that the angiotensin-converting enzyme (ACE) DD genotype might be associated with pulmonary hypertension during exercise in patients with COPD. Therefore, this study was designed to determine whether ACE gene polymorphisms adversely affect tissue oxygenation during exercise in patients with COPD.


METHODS
Cross-sectional analysis.


METHODS
University hospital.


METHODS
Thirty-nine patients (14 patients with II genotype, 12 patients with ID genotype, and 13 patients with DD genotype).


METHODS
All patients underwent right-heart catheterization and constant-load exercise testing for 5 min on an ergometer.


RESULTS
The ratio of the change in oxygen delivery (DO(2)) to the increase in oxygen consumption (O(2)) during exercise (DeltaDO(2)/DeltaO(2)) was significantly lower in patients with the DD genotype (1.5 +/- 0.2) than in those with the II genotype (1.9 +/- 0.3, p = 0.0006) and the ID genotype (1.7 +/- 0.2, p = 0.037). Mixed venous oxygen tension (PO(2)) after exercise in patients with the DD genotype (23.5 +/- 1.5 mm Hg) was also significantly lower than in patients with the II genotype (26.7 +/- 1.6 mm Hg, p = 0.0002) and the ID genotype (25.0 plus minus 2.0 mm Hg, p = 0.045). In addition, the change in plasma concentration of lactate during exercise (DeltaLactate) was significantly higher in patients with DD genotype (33.3 +/- 4.3 mmol/L) than in those with the II genotype (25.5 +/- 3.6 mmol/L, p = 0.0002) and the ID genotype (28.8 +/- 4.0 mmol/L, p = 0.029). The mean pulmonary arterial pressure after exercise was significantly correlated with DeltaDO(2)/DeltaO(2) (r = - 0.423, p = 0.0076) but not with PvO(2) after exercise and with DeltaLactate.


CONCLUSIONS
The ACE DD genotype may be associated with an impairment in peripheral tissue oxygenation during exercise in patients with COPD.
Kanazawa
Hiroshi
H
Department of Respiratory Medicine, Graduate School of Medicine, Osaka City University, Abenoku, Osaka, Japan. kanazawa-h@med.osaka-cu.ac.jp
Otsuka
Toshihiro
T
Hirata
Kazuto
K
Yoshikawa
Junichi
J
D015444:Exercise / Q000502:physiology*; D005838:Genotype; D006801:Humans; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000378:metabolism*; D011110:Polymorphism, Genetic; D029424:Pulmonary Disease, Chronic Obstructive / Q000235:genetics* / Q000503:physiopathology; D012083:Renin / Q000235:genetics*
D012083:Renin; D010100:Oxygen