Serum concentration of angiopoietin-like protein 4 in patients with systemic sclerosis

Systemic sclerosis (SSc) is a connective tissue disease characterized by endothelial cell damage, perivascular inflammation and tissue hypoxia. Angiopoietin-like protein 4 (ANGPTL4) has been demonstrated to affect vascular permeability, inflammation and oxidative stress, thus may contribute to SSc pathogenesis.

The aim of the study was to evaluate serum ANGPTL4 in systemic sclerosis and correlate it with disease subtype (localized and diffuse, lcSSc and dcSSc respectively), disease duration, skin fibrosis and internal organ involvement.

Twenty-two patients with systemic sclerosis (15 lcSSc, 7 dcSSc) and thirteen healthy controls were analyzed. Clinical and laboratory data were collected including modified Rodnan Skin Score (mRSS), Raynaud's phenomenon, disease duration, digital pitting scars, oesophageal involvement and interstitial lung disease. ANGPTL4 sera concentrations were measured by ELISA.

Patients with systemic sclerosis had lower ANGPTL4 serum levers in comparison to healthy controls, however without statistical significance (160.15 ± 117.53 vs. 127.15 ± 83.58 ng/ml; p=0.64). No association between ANGPTL4 levels and disease subtype, disease duration, severity of skin involvement (mRSS) and Raynaud's phenomenon onset was found.

This is the first study evaluating the serum concentration of ANGPTL4 in patients with systemic sclerosis. This study contributes to still undetermined role of ANGPTL4 in the development or progression of systemic sclerosis. Therefore the role of ANGPTL4 in hypoxia-related diseases such as systemic sclerosis needs further research.