Pathophysiologic considerations for the interactions between obstructive sleep apnea and sickle hemoglobinopathies.

Area of Science:

• Hematology
• Pulmonology
• Genetics

Background:

• Contradictory reports exist on obstructive sleep apnea (OSA) effects on vaso-occlusive events in sickle hemoglobinopathies.
• Current focus is on OSA-associated hypoxemia's impact on hemoglobin S (HbS) polymerization.
• Recent understanding suggests OSA's influence on sickle cell vaso-occlusion is more complex than just hypoxemia.

Purpose of the Study:

• To explore the multi-pathway interactions between obstructive sleep apnea and sickle cell vaso-occlusion.
• To investigate if OSA can exacerbate sickle cell trait, leading to overt clinical disease.
• To lay the groundwork for studies comparing sickle cell trait events with and without OSA.

Main Methods:

• Review of current understanding of sickle cell vaso-occlusion pathogenesis.
• Analysis of physiological consequences of OSA.
• Theoretical modeling of interactions between OSA and sickle cell disease pathways.

Main Results:

• Sickle cell vaso-occlusion involves multiple pathways: HbS polymerization, red cell-endothelial interactions, hypercoagulability, neutrophil activation, and vasoactive factors.
• These pathways are theoretically abnormal in OSA, potentially initiating or worsening vaso-occlusion.
• OSA might convert sickle cell trait into a clinically apparent disease.

Conclusions:

• OSA's impact on sickle cell disease likely involves complex interactions beyond simple hypoxemia.
• Further studies are needed to compare clinical events in sickle cell trait patients with and without OSA.
• Investigating the relationship between OSA, environmental hypoxia, and sickle cell trait events is a crucial next step.