The following is a summary of “Cellular and Enzymatic features of thrombi in humans are Vascular bed-dependent,” published in the September 2024 issue of Hematology by Bender et al.
The mechanisms behind how blood vessels change after thrombosis are still unclear. While acute arterial thrombosis in the brain can have devastating effects and requires immediate action, managing venous thromboembolism (VTE) differs widely.
Researchers conducted a retrospective study identifying the molecular markers and cell content of thrombi removed through catheter-directed thrombectomy (CDT) to understand vascular remodeling better.
They undertook 25 patients for CDT, 13 for cerebrovascular accidents (CVA), 8 for pulmonary embolism (PE), and 4 for deep vein thrombosis (DVT). Thrombi were collected for protein and RNA extraction, followed by immunoblotting, RNA sequencing, and gene expression analysis. Also, thrombi were collected within 7.7 ± 1.9 hours from symptom onset for CVA and 109 ± 55 hours for VTE.
The results showed that the venous thrombi showed higher protein concentration, white blood cell (monocyte), and red blood cell content than arterial thrombi. However, platelet content was similar in both. Matrix metalloproteinase (MMP) family enzymes, particularly MMP9, were present in both types, with MMP9 activity significantly higher in venous thrombi (61 ± 9 ng/mL/μg protein-1 vs. 25 ± 6 ng/mL/μg protein-1, P=0.005). Arterial and venous thrombi displayed distinct characteristics, with active enzymes driving blood vessel remodeling and more enzymatic activity in older venous thrombi.
Investigators concluded that early CDT in venous thrombi could help prevent irreversible changes in blood vessels as enzymatic activity increases with thrombus age.
