Microparticles in sickle cell disease

Area of Science:

• Hematology
• Vascular Biology
• Biomarker Discovery

Background:

• Sickle cell disease (SCD) is a prevalent hemoglobinopathy characterized by red blood cell (RBC) dysfunction.
• Circulating microparticles (MPs), which are submicron vesicles released from activated blood cells, are elevated in SCD patients.
• MPs are implicated in vascular disease and possess functional biological properties.

Purpose of the Study:

• To review the current understanding of microparticle (MP) release and function in sickle cell disease (SCD).
• To highlight the potential of MPs as biomarkers for vascular complications in SCD.
• To identify knowledge gaps regarding the functional properties of circulating MPs in human SCD.

Main Methods:

• Literature review of studies investigating microparticles (MPs) in sickle cell disease (SCD).
• Analysis of factors contributing to increased MP release in SCD, including sickling, oxidative stress, and RBC acid sphingomyelinase activity.
• Examination of ex vivo findings on the pro-inflammatory and pro-adhesive effects of sickle RBC-derived MPs.

Main Results:

• Plasma MP levels, primarily from platelets and RBCs, are consistently higher in steady-state SCD patients compared to healthy individuals.
• Conflicting data exists on the impact of SCD complications and hydroxyurea treatment on MP levels, often due to methodological variations.
• Ex vivo studies show that sickle RBC-derived MPs can induce oxidative stress and promote inflammation and adhesion in endothelial cells, potentially contributing to renal occlusion.

Conclusions:

• Elevated circulating microparticles (MPs) are a hallmark of sickle cell disease (SCD).
• While ex vivo studies suggest MPs contribute to vascular pathology, their precise functional roles in human SCD require further investigation.
• Standardization of pre-analytical and analytical procedures is crucial for reliable MP quantification and interpretation in SCD research.