Identification of diagnostic and prognostic indicators of hypercoagulability in patients with pseudoexfoliation syndrome

Abstract

Purpose : Pseudoexfoliation (PEX) syndrome is an age-related disease that may affect all vascular structures of the body due to the accumulation of degraded abnormal fibrillar deposits in the intraocular and extraocular tissues. This vascular structure may generate the inflammation environment and alter the morphological or functional protein structure of platelets. In this study, we tested the relationship between clot dynamics and platelet activation markers. The aim of our study is to find specific biomarkers with a diagnostic and prognostic value that will independently predict the PEX syndrome.

Methods : Two groups were included in this study, 1- Patients with ocular PEX syndrome (n=19) 2- Sex-matched individuals without ocular PEX syndrome (n=19). Ophthalmological examination and complete blood count measurements were performed in all participants aged between (40-75) years. Patients with von Willebrand disease, platelet dysfunction, diabetes, and ones using anticoagulant drugs were excluded. Peripheral blood was collected, analyzed by ROTEM (EXTEM, INTEM, and FIBTEM) tests, and flow cytometry was performed to analyze the expression of CD 41a, CD42b, CD61, CD62p, and PAC-1. A one-tailed Mann-Whitney test was used for statistical analysis.

Results : Analysis of the ROTEM data showed that the FIBTEM coagulation time (67.4 vs 60.3s; P <0.05) and the FIBTEM alpha angle (73.3 vs 70.0; P <0.05) increased in the PEX patients compared to the control group. Flow cytometry findings showed that there was a significant difference in the CD62p surface expression (P < 0.0001) and PAC-1 surface expression (p=0.018) between the PEX patients and the control group. Furthermore, analysis of antigen-binding capacity showed a significant difference only in the CD62p marker (P=0.0178).

Conclusions : To the best of our knowledge, this study is the first to examine clot dynamics and platelet activation markers in PEX patients. ROTEM results illustrated the higher contribution of functional fibrinogen in clot formation in the PEX patients. Flow cytometry data show that platelet activation markers are significantly elevated in PEX patients, suggesting the presence of a prothrombotic state. Further studies are recommended to investigate the exact role of platelets and functional fibrinogen in the initiation or development of PEX syndrome.

This is a 2021 ARVO Annual Meeting abstract.