Active clinical trials for "Anemia, Sickle Cell"

This research is being done to evaluate if the phosphodiesterase type 5 (PDE5) inhibitor sildenafil has an effect on the frequency of recurrent priapism and the quality of life of males with sickle cell disease (SCD).

Recent clinical and experimental data indicate that statins have effects beyond cholesterol lowering that may be beneficial in sickle cell disease by protecting the vascular endothelium. Statins have been shown to attenuate endothelial dysfunction through their anti-inflammatory, anti-oxidant and anti-thrombotic properties. This phase I/II dose-escalating trial is designed to assess the safety and potential clinical efficacy of oral simvastatin (Zocor)in adolescents and adults with sickle cell disease (SCD).

The main purpose of this project is to cure patients with high risk Sickle cell disease and other red cell disorders including thalassemia and diamond-blackfan anemia by bone marrow transplantation. The patients enrolled in this study will be those who lack matched sibling donors and therefore have no other option but to undergo bone marrow transplantation using matched but unrelated bone marrow or umbilical cord blood from the national marrow donor program registry. Since bone marrow transplantation for these disorders using matched unrelated donors has two major problems i.e. engraftment, or , the process of new marrow being accepted and allowed to grow in the the patient; and graft-versus-host disease, or the process where the new marrow "rejects" the host or the patient, this study has been devised with methods to overcome these two problems and thus make transplantation from unrelated donors both successful in terms of engraftment and safe in terms of side effects, both acute and long term. In order to accomplish these two goals, two important things will be done. Firstly, patients will get three medicines which are considered reduced intensity because they are not known to cause the serious organ damage seen with conventional chemotherapy. These medicines, however, do cause intense immune suppression so these can cause increased infections. Secondly, in addition to transplantation of bone marrow from unrelated donors, patients will also transplanted with mesenchymal stromal cells derived from the bone marrow of their parents. Mesenchymal stromal cells are adult stem cells that are normally found in the bone marrow and are thought to create the right background for the blood cells to grow. They have been shown in many animal and human studies to improve engraftment. In addition, they have a special property by which they prevent and are now even considered to treat graft versus host disease. Therefore, by using a reduced intensity chemotherapy regimen before transplant and transplanting mesenchymal stromal cells, we hope to improve engraftment while at the same time decrease the potential for severe side effects associated with a conventional transplant which uses extremely high doses of chemotherapy.

This study will examine whether nitric oxide (NO) gas can reduce the time it takes for pain to go away in patients who are in sickle cell crisis. NO is important in regulating blood vessel dilation, and consequently, blood flow. The gas is continuously produced by cells that line the blood vessels. It is also transported from the lungs by hemoglobin in red blood cells. Patients 10 years of age or older with sickle cell disease (known SS, S-beta-thalassemia or other blood problems causing sickle cell disease) may be eligible for this study. Patients whose disease is due to hemoglobin (Hgb) SC are excluded. Candidates are screened with blood tests and a chest x-ray to look at the lungs and heart. Participants are admitted to the hospital in a pain crisis. They are evaluated and then randomly assigned to receive one of two treatments: 1) standard treatment plus NO, or 2) standard treatment plus placebo. The placebo used in this study is nitrogen, a gas that makes up most of the air we breathe and is not known to help in sickle cell disease. For the first 8 hours of the study, patients receive placebo or NO through a facemask. The mask may be taken off for 5 minutes every hour and for not more than 20 minutes to eat a meal. After the first 8 hours, the gas is delivered through a nasal cannula (small plastic tubing that rests under the nose) that may be taken off only while showering or using the restroom. Patients are questioned about the severity of their pain when they start the study and then every few hours while they are in the hospital. Their vital signs (temperature, breathing rate, and blood pressure) and medicines are checked. Patients will breathe the gas for a maximum of 3 days, but will stay hospitalized until the patient feels well enough to go home. Patients are followed up about 1 month after starting the study by a return visit to the hospital or by a phone call.

This study examines ways in which nitric oxide (NO), an important molecule that controls how blood flows through the body's vessels, might be restored with a compound called sodium nitrite. It is hoped that the result will reverse the effect of decreased flow of blood due to sickled cells-that is, cells that have changed into the shape of a crescent or sickle. Sickle cell disease is the most common genetic disease affecting African Americans. About 8% of that population has the sickle cell trait. The changed cells can become attached to blood vessels, decreasing blood flow to vital organs. There can be the loss of needed proteins, including hemoglobin, that deliver oxygen throughout the body. Adults at least 18 years of age who have the SS form of sickle cell disease or S-beta-thalassemia, are in either a steady state or crisis, give informed and written consent for participation, and have had a negative pregnancy test may be eligible for this study. Adults with any other disease that puts them at risk for reduced circulation are not eligible. Women who are breastfeeding are not eligible. Participants will undergo a medical history, including family medical history, and a detailed physical evaluation, to take about 1 hour. There will be a collection of blood; echocardiogram, which involves taking a picture of the heart and its four chambers; and measurement of exhaled carbon monoxide, carbon dioxide, and NO. A procedure called orthogonal polarization spectral imaging will be performed. A small object the size of a Popsicle stick will be placed under the tongue or on a fingertip. This procedure presents a picture of blood flow and how the red blood cells appear as they circulate through blood vessels. The study will be conducted in the Vascular Laboratory/Cardiovascular Floor or Intensive Care and will last about 4 hours. During the study, patients will lie in an adjustable reclining bed and chair. Small tubes will be placed in the artery and vein of the forearm at the inside of the elbow. A small pressure cuff will be applied to the wrist and a larger one to the upper arm. Both cuffs will be inflated with air. A strain gauge, resembling a rubber band, will go around the widest part of the forearm. When the pressure cuffs fill with air, blood will flow into the arm, and information from the strain gauge will be recorded. Between administrations of each medicine, there will be 30-minute rests. Normal saline will be put into the small tube in the artery. Measurements of the blood flow in the forearm will be taken, and a small blood sample will be taken to measure blood counts, proteins, and other natural body chemicals. Then a medicine called sodium nitroprusside, which causes blood vessels to expand and increase blood flow, will be placed into the forearm. It will be given at three different doses for 3 minutes each, with measurements recorded after each dose. Then a medicine called L-NMMA will be placed into the forearm. L-NMMA generally decreases local blood flow by preventing nitric oxide from being produced in the cells lining the blood vessels. It will be given at two different doses for 5 minutes each, with blood flow measured after each dose. Next, nitrite will be placed in the forearm at three different doses for 5 minutes each. Before and after nitrite is given, the researchers will measure the amount of the NO, carbon monoxide, and carbon dioxide that the patients breathe out. Then the procedure for administering normal saline, sodium nitroprusside, and L-NMMA will be repeated, as will a blood test. This study will not have a direct benefit for participants. However, it is hoped that the information gained from the study will help to develop treatment options for patients with sickle cell disease.

This study will examine the effects of oral atorvastatin on the linings of blood vessels in patients with sickle cell disease, plus the agent's effect on blood markers of inflammation and blood vessel function. Sickle cell disease is a recessive genetic disorder and the most common genetic disease affecting African Americans. Inherited are abnormal genes that make hemoglobin, the substance within red blood cells that carries oxygen from the lungs to the body. In the disease, sickle hemoglobin leads to rigidity or hardness of the red cells, causing obstruction in small blood vessels, inflammation, and injury to organs when the flow of blood to them is blocked. Some medications already prescribed for other diseases, such as atorvastatin, which is used for lowering cholesterol levels, can improve blood flow. Patients 18 to 65 years of age who have sickle cell disease, who have not had an acute pain episode within the previous week, and who are not pregnant or lactating may be eligible for this study. They will undergo a complete medical history; physical examination; baseline blood tests; and echocardiogram, in which an ultrasound wand is placed against the chest wall to get images inside the heart and blood vessels. In addition, patients will have blood flow studies. During the procedure, they will lie in an adjustable reclining chair for 5 to 6 hours. There will be 20- to 30-minute rests between specific activities and blood samples will be drawn intermittently for testing. Small tubes will be placed in the artery of the forearm at the inside of the elbow. Normal saline will be infused into one tube. A small pressure cuff will be applied to the wrist and a larger cuff to the upper arm. Both cuffs will be attached to an inflation device. A device like a rubber band, a strain gauge, will be placed around the widest part of the forearm. When the pressure cuffs are inflated, blood will flow into the arm, stretching the gauge proportion to blood flow, and information will be recorded. Then light reflected from the patients' hand and the blood flow in the forearm will be measured. Activity of the genes in the white blood cells will be measured as well. Small amounts of sodium nitroprusside, widely used to reduce blood pressure in people with dangerously high blood pressure, will be injected and blood flow will be measured. Later, small amounts of acetylcholine will be injected. It usually causes blood vessels to expand. After that, small amounts of L-NMMA will be injected. It usually decreases local blood flow by blocking the production of nitric oxide in the cells lining the arm's blood vessels. Then acetylcholine combined with L-NMMA will be injected. After that, oxypurinol, an agent taken by many patients to prevent gout, will be injected. The procedures will be repeated, with oxypurinol given along with each of the agents, and the measurement of blood flow in the forearm will be measured after each drug combination. Afterward, patients will be treated for 4 weeks at home with oral atorvastatin. They will be asked to visit the Clinical Center every 2 weeks for collection of blood samples and an examination. After 4 weeks of taking atorvastatin orally, they will be asked to return to repeat the blood flow studies, but only the first half will be conducted. The part using oxypurinol will not be needed. Regarding some of the blood samples collected during the study, there will be an examination of the genes found in the white blood cells. Specific attention will go to those genes that make proteins for cell-to-cell interaction and inflammation, plus those that cause blood cells to stick to the lining of blood vessels.

The purpose of this study is to compare standard therapy (transfusions and chelation) with alternative therapy (hydroxyurea and phlebotomy) for the prevention of secondary stroke and management of iron overload in children with sickle cell anemia (SCA).

The goal of this research study is to establish chimerism and avoid graft-versus-host disease in patients with Hemoglobinopathies to halt disease progression.

This is a clinical trial of bone marrow transplantation for patients with the diagnosis of a genetic disease of blood cells that do not have an HLA-matched sibling donor. Genetic diseases of blood cell include: Red blood cell defects e.g. hemoglobinopathies (sickle cell disease and thalassemia), Blackfan-Diamond anemia and congenital or chronic hemolytic anemias; White blood cells defects/immune deficiencies e.g. chronic granulomatous disease, Wiskott-Aldrich syndrome,Osteopetrosis, Kostmann's syndrome (congenital neutropenia), Hereditary Lymphohistiocytosis (HLH); Platelets defects e.g.Congenital amegakaryocytic thrombocytopenia; Metabolic/storage disorders e.g. leukodystrophies,mucopolysaccharidoses as Hurler disease;Stem cell defects e.g.reticular agenesis, among many other rare similar conditions. The study treatment plan uses a new transplant treatment regimen that aims to try to decrease the acute toxicities and complications associated with the standard treatment plans and to improve outcome The blood stem cells will be derived from either unrelated donor or unrelated umbilical cord blood.

The purpose of this study is to assess prospectively the efficacy of hydroxyurea therapy in the setting of cerebrovascular disease, manifest as conditional or abnormal transcranial doppler ultrasonography (TCD) flow velocities, in children with sickle cell anemia (SCA). TCD is used to measure flow velocity in intracranial arteries as a marker of increased stroke risk in children with SCA. The primary objective of this protocol is to determine whether hydroxyurea reduces elevated TCD velocity.