Serum levels of angiotensin converting enzyme 2 in patients with systemic sclerosis

Background: Systemic sclerosis (SSc) is an autoimmune disorder with fibrosis of the skin and internal organs. Angiotensin-converting enzyme 2 (ACE2) breaks down angiotensin II to the antifibrotic and anti-inflammatory angiotensin (1-7). Aim of the work: To assess the serum levels of ACE2 in SSc patients and to determine the association between its levels with the clinical features and disease severity. Patients and methods: Serum from 44 patients with SSc and 35 age and sex matched controls were assayed for ACE2 concentrations by enzyme linked immunosorbent assay. The modified Rodnan skin score (mRSS) was evaluated. Results: Patients were 41 females and 3 males (F:M 13.7:1) with a mean age of 40.4 +/- 11.3 years, and median disease duration of 5 years. Thirty-four patients had limited cutaneous SSc (lcSSc) and 10 had diffuse cutaneous SSc (dcSSc). Interstitial lung disease was present in 30 (68.2 %) patients. The median mRss was 11 (4-35). The antiscleroderma-70 and anticentromere antibodies were positive in 36.4 % and 29 %, respectively. The ACE2 level was significantly lower in SSc (1.02 ng/ml; 0.13-4.25 ng/ml) compared to control (1.57 ng/ml; 0.24-23.69 ng/ml) (p = 0.026) and in females compared to males (0.8; 0.13-4.15 ng/ml vs 3.33; 1.32-4.25 ng/ml) (p = 0.04) while the levels were comparable between lcSSc and dcSSc (p = 0.88). The level was lower in those with telangiectasia (n = 24), (p = 0.048) and in those receiving cyclophosphamide (n = 11), (p = 0.038) compared to those without. There was a non-significant correlation between ACE2 level and mRss (p = 0.16). Conclusions: Serum ACE2 levels are decreased in patients with SSc and related to telangiectasias and the use of cyclophosphamide.