Adhesion molecules in focus: mechanistic pathways and therapeutic avenues in sickle cell vaso-occlusion - a narrative review.

Sickle cell disease (SCD) is a genetic disorder characterized by the presence of sickle-shaped red blood cells (sRBCs), which are prone to occluding small blood vessels, leading to severe pain and organ damage. One of the critical mechanisms driving vaso-occlusion in SCD is the interaction between sRBCs, leukocytes, platelets, and endothelial cells, mediated by adhesion molecules. These molecules, including intercellular adhesion molecule-1, vascular cell adhesion molecule-1, selectins, and integrins, play a significant role in promoting the adhesion of these cells to the vascular endothelium, exacerbating inflammation, and contributing to the obstruction of blood flow. Understanding how these adhesion molecules participate in the pathophysiology of vaso-occlusion offers valuable insights into potential therapeutic strategies to mitigate the impact of this debilitating condition. The role of adhesion molecules in SCD-induced vaso-occlusion has been well-documented, with multiple studies showing that their upregulation enhances the interaction between sickled and non-sickled cells and the endothelium. This interaction initiates a cascade of inflammatory responses that worsen microvascular occlusion, leading to tissue ischemia and chronic complications. The expression of adhesion molecules such as E-selectin, P-selectin, and integrins on both the endothelial surface and the sickle cell membrane is critical for the progression of these vaso-occlusive events. Inflammation-induced overexpression of these molecules increases cell adhesion, exacerbating the frequency and severity of vaso-occlusive crises and contributing to long-term organ damage in SCD patients.