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Published on: August 4, 2023
Increased procoagulant cell-derived microparticles (C-MP) in splenectomized patients with ITP
1Wallace H Coulter Platelet Laboratory, Division of Hematology/Oncology, University of Miami, Miller School of Medicine, 1600 NW 10th Ave, Room 7109A, Miami, FL 33136, USA.
Background:
Splenectomy is frequently employed for therapeutic and diagnostic purposes in various clinical disorders. However its long-term safety is not well elucidated. Although risk of infection by encapsulated organisms is widely recognized, less well-known are risks of thrombosis and cardiovascular disease.
Methods:
We investigated levels of cell-derived microparticles (C-MP) in 23 splenectomized ITP (ITP-S) and 53 unsplenectomized ITP patients (ITP-nS). Assay of C-MP derived from platelets (PMP), leukocytes (LMP), red cells (RMP) and endothelial cells (EMP) were performed by flow cytometry. Coagulation parameters included PT, aPTT and activities of FVIII, IX and XI. Results of all measures were compared between the two groups, ITP-S vs ITP-nS.
Results:
Levels of all C-MP were higher in ITP-S than ITP-nS but only RMP and LMP reached statistical significance (p = 0.0035 and p < 0.0001, respectively). The aPTT was significantly shorter in ITP-S (p = 0.029). Interestingly, correlation analysis revealed that RMP, but not other C-MP, were associated with shortening of aPTT (p = 0.024) as well as with increased activities of factors VIII (p = 0.023), IX (p = 0.021) and XI (p = 0.0089).
Conclusions:
RMP and LMP were significantly elevated in splenectomized compared to non-splenectomized ITP patients. This suggests that the spleen functions to clear procoagulant C-MP, and that elevation of C-MP might contribute to increased risk of thrombosis, progression of atherosclerosis and cardiovascular disease following splenectomy.
Insights
Splenectomy increases cell-derived microparticles (C-MP), particularly red cell-derived (RMP) and leukocyte-derived (LMP), potentially raising thrombosis and cardiovascular disease risks. The spleen likely clears these procoagulant C-MP.
Area of Science:
- Hematology
- Immunology
- Vascular Biology
Background:
- Splenectomy is a common procedure with incompletely understood long-term safety.
- While infection risk is known, thrombosis and cardiovascular disease risks post-splenectomy require further elucidation.
Purpose of the Study:
- To investigate levels of cell-derived microparticles (C-MP) in splenectomized versus non-splenectomized patients with immune thrombocytopenia (ITP).
- To explore the association between C-MP levels, coagulation parameters, and potential long-term risks following splenectomy.
Main Methods:
- Assessed levels of platelet-derived (PMP), leukocyte-derived (LMP), red cell-derived (RMP), and endothelial cell-derived (EMP) microparticles via flow cytometry.
- Measured coagulation parameters including PT, aPTT, and FVIII, IX, XI activities.
- Compared these measures between 23 splenectomized ITP (ITP-S) and 53 non-splenectomized ITP (ITP-nS) patients.
Main Results:
- Significantly elevated RMP (p=0.0035) and LMP (p<0.0001) were observed in ITP-S patients compared to ITP-nS.
- ITP-S patients exhibited significantly shorter aPTT (p=0.029).
- RMP correlated with shorter aPTT and increased activities of factors VIII, IX, and XI.
Conclusions:
- Splenectomy is associated with elevated RMP and LMP, suggesting the spleen's role in clearing procoagulant C-MP.
- Increased C-MP levels post-splenectomy may contribute to heightened risks of thrombosis, atherosclerosis, and cardiovascular disease.
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