Exploring Near Infrared Spectroscopy (NIRS) Technologies for Assessment of Muscle Physiology, Tissue Oxygenation, and Blood Flow in Patients With Sickle Cell Disease (SCD)

Sickle cell disease (SCD) is an inherited disorder of the blood. SCD can injure the smallest blood vessels, which can cause pain and damage organs all over the body. Some treatments are available, but researchers need better ways to monitor the effects of these treatments. An imaging technique called near infrared spectroscopy (NIRS) may be helpful.Objective:To test NIRS as a tool for measuring oxygen levels, blood flow, and the makeup of skin and muscle in patients with SCD.Eligibility:People aged 18 years and older with SCD. Healthy volunteers are also needed as a comparison for the changes in SCD patients.Design:Participants will be screened. They will have a physical exam, and 1 teaspoon of blood will be drawn.Participants will have NIRS testing on their second visit. Probes will be placed on their skin. A blood pressure cuff will be placed on their arm. The cuff will be filled with air for up to 5 minutes and then released. Participants may be asked to breathe at a certain rate or hold their breath during these measurements.At this visit, participants will also have an ultrasound exam to get images of their heart. They will be monitored while they walk for 6 minutes. They will have 1 tablespoon of blood drawn. Their height, weight, and vital signs will be measured.Participants may be asked to return for up to 4 additional visits for NIRS testing within 120 days, but this is optional. The visits must be at least 3 days apart. Each visit will last up to an hour....

INCLUSION CRITERIA:Sickle Cell DiseaseIndividuals with confirmed sickle cell disease (HbSS and S beta 0 genotypes)18 years of age and olderWillingness and capacity to provide informed consentEthnically matched controlsIndividuals with HbAA genotype18 years of age and olderWillingness and capacity to provide informed consentEXCLUSION CRITERIA:Sickle Cell DiseasePain crisis requiring parenteral treatment within 4 weeks of screening/enrollmentBlood transfusion within 60 days or exchange transfusion within 90 days of screening/enrollmentUse of Oxbryta (voxelotor), Adakveo (crizanlizumab), and/or Endari (L-glutamine) within the 12 weeks prior to signing consentWomen who are currently pregnantPresence of an arterial-venous shunt, recent axillary node dissection, or any deformity or surgical history that interferes with proper access for brachial cuff occlusion procedure of the extremitiesMobility difficulties causing the inability to complete 6-minute walk testEthnically matched controlsWomen who are currently pregnantPresence of an arterial-venous shunt, recent axillary node dissection, or any deformity or surgical history that interferes with proper access for brachial cuff occlusion procedure of the extremitiesMobility difficulties causing the inability to complete 6-minute walk testBlood transfusion within 60 days or exchange transfusion within 90 days of screening/enrollment