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Sickle Cell Centers

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Current Research

Current Multi-Center Projects Supported by the SDMC

Arginine Supplementation in Sickle Cell Anemia: Physiological and Prophylactic Effects

Nitric oxide is an important inflammatory mediator produced from arginine by nitric oxide synthase. Nitric oxide has a multitude of functions which could impact favorably on vaso-occlusion in sickle cell disease. Oral arginine has been shown to raise levels of nitric oxide. This study will test whether daily oral arginine results in an increase in nitric oxide and other beneficial effects in patients with sickle cell disease. The results of this study will serve as the basis for further clinical trials to determine if daily arginine is a beneficial therapy for patients with sickle cell disease.

Comprehensive Sickle Cell Centers Collaborative Data Project

The Comprehensive Sickle Cell Centers (CSCC) Collaborative Data Project will establish a comprehensive database of individuals from participating Centers who are potentially eligible for inclusion in any sickle cell research study. Such studies include observational (incidence/prevalence, cohort, case-control, cross-sectional) as well as interventional (randomized clinical trials) investigations. Possible study endpoints include traditional clinical and therapeutic measurements, health resource utilization, and patient-reported outcomes. The Collaborative Data Project encompasses these clinical and outcomes databases within the Patient Database component of the Project, and includes additional components of specifically developed tools and methodologies required for practical, quality data capture, management, and utilization. A secure web-based Electronic Data Capture system will be provided to Centers to allow data submission to the Statistics and Data Management Center. Adherence to all Federal Guidelines regarding privacy and confidentiality will be rigorously maintained.

Several posters have been presented at national research meetings:

Dexamethasone

Although Acute Chest Syndrome (ACS) is a common cause of hospitalization among SCD subjects, standard treatment is primarily supportive. This Phase III double-blind RCT will study the effectiveness of Dexamethasone in treating ACS, among subjects with HbSS and HbS?0) disease who are hospitalized with a new episode of ACS. This study includes a taper dosing regimen of no more than eight days that may circumvent the "rebound" re-hospitalizations associated with steroids in this population. The primary endpoint is time to resolution of ACS symptoms; secondary endpoints include time in hospital and biomarkers. The study began enrollment in December 2006.

Neuropsychological Dysfunction and Neuroimaging Abnormalities in Neurologically Intact Adult Patients With Sickle Cell Disease (SCD)

Once a fatal pediatric disease, sickle cell disease has become a chronic adult illness. Pediatric neurological studies and pilot data in adult sickle cell patients suggest brain dysfunction may be the most important and least-studied problem afflicting an aging sickle cell population. The Neuropsych study is a two-phase design. In Phase I, approximately 156 subjects will complete a cross-sectional investigation designed to compare neuropsychological function of adult neurologically normal HbSS/SB0 subjects with matched-peer controls. This phase consists of screening questionnaires, a neuropsychological testing battery, and MRI testing. In Phase II, a subset of approximately 36 participants from Phase I will be asked to participate in a transfusion intervention. Half will be randomized to undergo a chronic transfusion regimen for six months, and the other half will be treated with standard care alone, guided by their disease symptoms, with the goal of improving cognitive function through correction of anemia.

Epidemiology of Priapism

Priapism, a prolonged erection of the penis that may lead to impotence, is a specific type of painful crisis that commonly occurs in patients with sickle cell disease. The current treatment of priapism can be improved by comparing therapeutic strategies in prospective clinical trials, but first an assessment of the natural history of priapism is needed. This project will conduct an interview of 1,650 males with sickle cell disease in order to determine in which patients, how often, and under what circumstances priapism occurs.

Effectiveness of Hydroxyurea and Magnesium Pidolate Alone and in Combination in Hemoglobin SC Disease: A Phase II Trial

Hemoglobin (Hb) SC disease is characterized by dense red blood cells, but treatment approaches aimed at its pathophysiology have been limited in scope. Furthermore, combination drug therapy in sickle cell disease has not been adequately tested. We will examine two oral therapies, hydroxyurea and magnesium, given by themselves and in combination and compare them to placebo in a double-blinded Phase II study to determine their efficacy in reducing red cell density in Hemoglobin SC in children and adults. We will also examine their effects on other red cell characteristics and on the frequency of clinical vaso-occlusive events. To accomplish this, 188 subjects will be assigned randomly to one of four treatment groups (see below) and followed for one year after beginning treatment.