This is an application to establish a Sickle Cell Disease Clinical Center at Howard University and Childrens National Medical Center in Washington, DC that will also collaborate with the sickle cell disease program at the Clinical Center of the National Institutes of Health in Bethesda, MD. The institutions participating in this Clinical Center follow over 1000 patients with sickle cell disease (SCO) and enroll more than 100 new patients per year. The objectives of the Howard-CNMC Sickle Cell Clinic Center are as follows. Objective 1. To develop the local research infrastructure required for designing and implementing clinical protocols, primarily clinical trials, as part of a multi-center Network of clinics currently treating a large number of sickle cell patients. The Network's main objective is to advance the management of sickle cell disease (SCO) and other hemoglobinopathies by testing the safety, efficacy and effectiveness of new therapeutic and preventive interventions. Objective 2. To propose two multi-center clinical trials as candidate protocols for the Sickle Cell Network. Both trials will focus on lowering sickle cell complications by improving vascular function. The first trial will determine whether atorvastatin administration prevents vaso-occlusive events (crises, ACS). The second study will examine whether the combination of the NO donors, hydralazine and isosorbide dinitrate, prevent the development of pulmonary hypertension and progression of renal/CNS/systemic vasculopathy in SCD patients who have a relative elevation in systemic systolic blood pressure. Objective 3. To help provide comprehensive, state of the art care to children and adults with sickle cell disease (SCD) enrolled in Network clinical protocols. For several decades both, the Howard University Center for Sickle Cell Disease and its proposed collaborating institution, Childrens' National Medical Center (CNMC), have been providing this type of care to a large population of Washington, DC area sickle cell patients. A major feature of both sickle cell programs has always been continuity of care and participation in collaborative research.