Background The oxidative stress markers as risk factor for endothelial dysfunction in primary and secondary antiphospholipid syndrome.
Objectives Antiphospholipid syndrome (APS) may manifest as a primary (PAPS) or as a secondary disease (SAPS). It is featured by clinical manifestations in the presence of antiphospholipid antibodies (aPL). Antioxidant status has been evaluated in patients with SLE, with conflicting results.
Methods The study involved 152 APS patients (95 PAPS, 57 SAPS) and 41 age/sex-matched controls. Brachial artery responses to reactive hyperaemia (endothelium-dependent dilatation) [FMD] and sublingual nitroglycerine (endothelium-independent dilatation) [NMD] were measured by using high-resolution vascular ultrasound. Markers of oxidative stress, including lipid hydroperoxydes (LOOH), advanced oxidation protein products (AOPP), total thyol groups and paraoxonase 1 activity (PON1) were determined by spectrophotometric method.
Results FMD in patients with PAPS and SAPS was significantly lower than those of the controls (p<0.001 and p<0.001, respectively) without difference in NMD. FMD impairment was similar in both APS groups. Risk factors for endothelial impairment were age (p<0.05), obesity (p=0.048) and hypertension (p=0.020) but not aPL. We also found statistically significant difference in prevalence of FMD and NMD impairment in PAPS patients with longer disease duration. LOOH and AOPP concentrations were significantly higher and thyol groups lower in APS patients comparing to control group as the same relations between SAPS to PAPS groups. APS patients with fetal losses had higher AOPP (p=0.002) as well as patients diagnosed with thrombosis (p=0.011). Impairment of FMD was found in APS patients with higher LOOH and AOPP concentrations (p=0.044 and 0.015, respectively). There was no difference between impairment of FMD and NMD according to aPL category (except LA positivity to FMD impairment in PAPS group) or clinical APS manifestation.
Conclusions Endothelial dysfunction is present in APS patients with marked oxidative imbalance. Oxidative stress is more prominent in SAPS than in PAPS group. Endothelial dysfunction is doubtlessly present in APS patients with oxidative imbalance as additional risk factor among other risk factors for clinical event. AOPP could be relevant prognostic factor for APS manifestations since it contribute to endothelial dysfunction and correlate to clinical APS manifestations.
Acknowledgement This work was supported by research grant number 175041 for 2011 - 2016, issued by the Ministry of Science of the Republic of Serbia, and by research grant number TR 32040 for 2011 - 2016, issued by the Ministry of Science of the Republic of Serbia.
Disclosure of Interest None declared