# Antiphospholipid antibodies are associated with increased levels of selected oxidative stress biomarkers

## TL;DR

This study shows that people with antiphospholipid antibodies have higher oxidative stress markers even without a history of blood clots.

## Contribution

The study demonstrates that oxidative stress is linked to antiphospholipid antibodies independently of thrombosis.

## Key findings

- TBARS, LOOH, and carbonyl groups were significantly higher in patients with antiphospholipid antibodies.
- Acetyl-lysine-containing fibrinogen levels were elevated in antibody-positive individuals.
- ROTEM tests did not show consistent signs of hypercoagulability.

## Abstract

Antiphospholipid antibodies (aPLs) are detected in 1–5% of the general population. They include lupus anticoagulant (LAC), anticardiolipin antibodies (aCL) and anti-β2-glycoprotein I antibodies (aβ2GPI). APL increases thrombotic risk, but the pathogenesis of this effect is not fully understood.

The aim of this study was to evaluate oxidative and nitrosative stress biomarkers and their relation to certain rotational thromboelastometry (ROTEM) parameters as a risk factor for thrombosis in 32 patients in whom the presence of antiphospholipid antibodies was confirmed, but who had never experienced a thrombosis event (Group 1) in order to rule out any impact of thrombosis on stress parameters. The parameters were also assessed in a group of 23 healthy volunteers (Group 2).

To assess FRAP and thiol groups we used colorimetric method. The level of protein carbonylation, total pool of 3-nitrotyrosine in plasma proteins, 3-nitrotyrosine-containing fibrinogen as well as the acetyl-lysine-containing fibrinogen were estimated by ELISA. Lipid hydroperoxides were detected using the ferric-xylenol orange hydroperoxide assay. Additionally four ROTEM tests, i.e. INTEM, EXTEM, FIBTEM and APTEM, were performed. In statistical analysis the Mann-Whitney U-test, Student’s t-test and logistic regression were used.

TBARS (p = 0,002), LOOH (p = 0,035) and carbonyl groups (p = 0,018) were markedly higher in Group 1 compared to Group 2. Also the acetyl-lysine-containing fibrinogen were significantly higher in Group 1 (p = 0,0028). Other biomarkers did not differ markedly between the studied groups. The obtained results of ROTEM, were not consistent and did not clearly indicate hypercoagulable state.

Study confirms increased levels of oxidative biomarkers in patients in whom the presence of antiphospholipid antibodies was confirmed, but who had never experienced a thrombosis event. Oxidative stress may an important role in the pathogenesis of APS and is not secondary to thrombosis.