Malondialdehyde and nitrotyrosine as markers of peroxynitrite activity in sarcoidosis

Sarcoidosis (SA) is granulomatous disease with unknown etiology. Infectious factors, genetics and autoimmunity are considered in the etiopathogenesis of SA. In contrast to tuberculosis (TB), we evidenced decreased clearance of immune complexes with mycobacterial heat shock proteins by resistant to apoptosis monocytes with diminished serum microbicidal/degradable nitrate/nitrite and increased concentration of peroxynitrite (ONOO-) in SA. ONOO- reacts with a variety of lipids and proteins initiating peroxidation process with subsequent oxidative tissue injury. Malondialdehyde (MDA) and nitrotyrosine (NT) are the final products of peroxynitrite formation. MDA is product of polyunsaturated fatty acids peroxidation in cells, whereas NT represents a specific peroxynitrite-mediated protein modification. The alterations may generate or mask antigenic epitopes and stimulate relevant T- and/or B-cells, leading to a breakdown or bypass of tolerance, e.g. in SA. Therefore in the same tested group, we evaluated serum levels of MDA and NT in 20 SA patients, 19 TB patients and 21 healthy volunteers using ELISA method. Our study revealed higher concentration of MDA and NT in TB and SA than in controls (p<0.001, p<0.001, respectively) but levels of these final products were higher in SA than TB (p<0.001, p<0.001, respectively). Increased levels of MDA and NT in our patients with SA than in TB highlight greater an imbalance between oxidants and antioxidants in the etiopathogenesis ...
Source: European Respiratory Journal - Category: Respiratory Medicine Authors: Tags: Diffuse Parenchymal Lung Disease Source Type: research