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Pulmonary capillary endothelial dysfunction in early systemic sclerosis
S E Orfanos1, E Psevdi, N Stratigis
1Department of Critical Care & Pulmonary Medicine, Evangelismos Hospital and University of Athens Medical School, Greece.
Arthritis and Rheumatism
|April 24, 2001
Summary
Pulmonary capillary endothelium-bound angiotensin-converting enzyme (PCEB-ACE) activity is reduced early in systemic sclerosis (SSc), indicating endothelial dysfunction. This reduction is more pronounced in diffuse cutaneous SSc (dcSSc) than limited cutaneous SSc (lcSSc), even without lung disease.
Area of Science:
- Cardiovascular research
- Pulmonary medicine
- Rheumatology
Background:
- Systemic sclerosis (SSc) involves endothelial damage and collagen formation, potentially leading to pulmonary hypertension (PH) or interstitial lung disease (PIF).
- Pulmonary capillary endothelium-bound angiotensin-converting enzyme (PCEB-ACE) activity serves as a key indicator of endothelial function.
Purpose of the Study:
- To investigate whether PCEB-ACE activity is reduced early in SSc patients, even before the development of PH or PIF.
- To compare PCEB-ACE activity between limited cutaneous SSc (lcSSc) and diffuse cutaneous SSc (dcSSc) subsets.
Main Methods:
- Indicator-dilution techniques were used to measure transpulmonary hydrolysis and percent metabolism (%M) of a synthetic ACE substrate in 25 SSc patients and 11 controls.
- Functional capillary surface area (FCSA) was calculated to assess ACE activity per vascular bed.
- High-resolution computed tomography (HRCT) was performed to evaluate PIF.
Main Results:
- PCEB-ACE activity was decreased in both SSc subsets.
- In patients without PH, substrate hydrolysis and %M were reduced in lcSSc and more significantly in dcSSc.
- FCSA/BSA loss was observed in dcSSc but not lcSSc, irrespective of PIF presence.
Conclusions:
- Reduced PCEB-ACE activity signifies early pulmonary endothelial dysfunction in SSc.
- This dysfunction occurs even in the absence of PH or PIF.
- The endothelial dysfunction is more pronounced in the early stages of dcSSc compared to lcSSc.