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Altered angiotensin I conversion in pulmonary disease.
Clinical Science and Molecular Medicine
|December 1, 1976
Summary
Plasma angiotensin I converting enzyme activity differs in lung diseases. Sarcoidosis patients showed increased activity, while COPD and shock lung patients had decreased activity, suggesting a link to pulmonary function.
Area of Science:
- Biochemistry
- Pulmonary Medicine
- Cardiovascular Physiology
Background:
- Angiotensin I converting enzyme (ACE) plays a crucial role in the renin-angiotensin system.
- ACE activity in plasma is often studied as a proxy for its activity in other tissues, particularly the lungs.
- Pulmonary diseases may influence systemic ACE activity.
Purpose of the Study:
- To develop and apply a method for measuring plasma ACE activity.
- To investigate plasma ACE activity in patients with specific lung conditions: sarcoidosis, chronic obstructive pulmonary disease (COPD), and shock lung.
- To compare plasma ACE activity in these patient groups with healthy controls.
Main Methods:
- A specific assay was developed using 125I-labelled angiotensin I as the substrate to measure ACE activity in plasma.
- Plasma samples were collected from normal subjects and patients with sarcoidosis, COPD, and shock lung.
- Inhibition studies were performed using varying concentrations of exogenous angiotensin I.
Main Results:
- Plasma ACE activity was significantly increased in patients with sarcoidosis compared to normal subjects.
- Plasma ACE activity was decreased in patients with COPD and shock lung.
- The degree of ACE conversion did not correlate with the severity of lung disease in COPD and shock lung patients.
- Differences in exogenous angiotensin I concentrations required for complete inhibition suggested altered ACE kinetics in disease states.
Conclusions:
- Plasma ACE activity can be altered in the presence of pulmonary disease.
- Increased plasma ACE activity in sarcoidosis and decreased activity in COPD/shock lung suggest a potential link between pulmonary pathology and systemic ACE levels.
- Plasma ACE activity measurement may serve as a valuable tool for understanding the renin-angiotensin system's role in cardiovascular homeostasis and disease.