Rethinking Sickle Cell Disease as a Systemic Vasculopathy

Sickle cell disease (SCD) is the most common inherited clinically relevant blood disorder. Although a deceptively simple monogenetic disorder, the associated complications have multiple downstream effects. In this review, we explore the many facets of SCD, with a particular focus on its impact on the vascular system. Despite progress in understanding the underlying mechanisms of SCD, including Hemoglobin S polymerization, microvascular occlusion, and inflammation, there are still many questions surrounding the condition, especially predicting which affected individuals will acquire specific complications in order to personalize treatments. While current standard of care treatments, including hydroxyurea and chronic red blood cell transfusions, have been proven to be disease-modifying, newer therapies like crizanlizumab and voxelotor have only proven to manage symptoms. Newer gene therapies have been approved; however, it is not clear what impact these will have long-term on the end-organ complications of SCD. There is still a significant need to understand how we optimize and personalize therapies to improve outcomes for patients. This review highlights the importance of recognizing SCD as a vascular disease to understand its multi-organ complications and heterogeneity of effects.