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Angiotensin-Converting Enzyme Gene Polymorphisms and Tissue Oxygenation During Exercise

Angiotensin-Converting Enzyme Gene Polymorphisms and Tissue Oxygenation During ExerciseThe angiotensin converting enzyme (ACE) gene contains a polymorphism based on the presence (insertion [I]) or absence (deletion [D]) within an intron of a 287 base-pair nonsense DNA domain, resulting in three genotypes (DD homozygote, II homozygote, and DI heterozygote). The ACE DD genotype is associated with increased circulating and cellular concentrations of ACE2, and with the increase in cardiovascular risk. However, the vast majority of the total activity of ACE in the body is found in lung tissue, and its activity is further increased by chronic hypoxia. Moreover, ACE expression is markedly and consistently increased in the walls of small pulmonary arteries during the development of hypoxia-induced pulmonary hypertension. Therefore, ACE in lung tissue may be involved in the pathogenesis of pulmonary hypertension secondary to COPD. canadian health and care mall

Recently, we determined that the ACE DD genotype might be associated with pulmonary hypertension with exercise in patients with COPD. Pulmonary hypertension becomes particularly pronounced in patients with COPD when the cardiovascular system is stressed during exercise. This excessive pulmonary hypertension might result in the disturbance of oxygen transport during exercise. However, peripheral tissue oxygenation during exercise in patients with COPD also appears to depend on peripheral factors, including microcirculation and enzymatic capacity of exercising muscles. The purpose of the present study was to determine whether the ACE gene polymorphisms adversely affect peripheral tissue oxygenation during exercise in patients with COPD.
Materials and Methods
Thirty-nine patients with COPD (all male patients) from the respiratory outpatient clinic of our institution were enrolled in this study. All had a history of smoking and severe irreversible airflow limitation.