Alloimmunization in sickle cell disease: changing antibody specificities and association with chronic pain and decreased survival.

Background: Alloimmunization remains a significant complication of transfusion and has been associated with multiple factors, including inflammation, an important pathophysiologic mechanism in sickle cell disease (SCD). We explored whether alloimmunization is associated with disease severity in SCD.

Study Design And Methods: Adult SCD patients were enrolled in a study of outcome-modifying genes in SCD.

A model for developing, evaluating, and disseminating best practices in education and training.

With the shift toward team-based translational science came recognition that existing strategies for training individual investigators and retaining them in the biomedical workforce would be inadequate. To support this shift, it is important to: develop innovative strategies to educate and train diverse members of research teams; evaluate those programs; and disseminate best practices broadly. We have developed a four-phase model to facilitate the development, evaluation, and widespread dissemination of innovative strategies to train the biomedical research workforce.

Detecting the emergence of chronic pain in sickle cell disease.

Context: Sickle cell disease (SCD) is an inherited hematological disease marked by intense pain. Early in life the pain is episodic, but it becomes increasingly chronic in many cases. Little is known about this emergence of a chronic pain state.

MYH9 and APOL1 are both associated with sickle cell disease nephropathy.

Renal failure occurs in 5-18% of sickle cell disease (SCD) patients and is associated with early mortality. At-risk SCD patients cannot be identified prior to the appearance of proteinuria and the pathobiology is not well understood. The myosin, heavy chain 9, non-muscle (MYH9) and apolipoprotein L1 (APOL1) genes have been associated with risk for focal segmental glomerulosclerosis and end-stage renal disease in African Americans.

Association of soluble fms-like tyrosine kinase-1 with pulmonary hypertension and haemolysis in sickle cell disease.

The pathophysiology of pulmonary hypertension (PHT) in sickle cell disease (SCD) is probably multifactorial. Soluble fms-like tyrosine kinase-1 (sFLT-1) is a member of the vascular endothelial growth factor receptor (VEGFR) family. By adhering to and inhibiting VEGF and placenta growth factor, it induces endothelial dysfunction.

Urinary albumin excretion is associated with pulmonary hypertension in sickle cell disease: potential role of soluble fms-like tyrosine kinase-1.

Background: Pulmonary hypertension (PHT) is reported to be associated with measures of renal function in patients with sickle cell disease (SCD). The purpose of this exploratory study was to determine the relationship between albuminuria and both clinical and laboratory variables in SCD.

Design And Methods: This cross-sectional study was performed using a cohort of adult patients with SCD and control subjects without SCD.

Neuropsychological dysfunction and neuroimaging abnormalities in neurologically intact adults with sickle cell anemia.

Context: Sickle cell anemia (SCA) is a chronic illness causing progressive deterioration in quality of life. Brain dysfunction may be the most important and least studied problem affecting individuals with this disease.

Objective: To measure neurocognitive dysfunction in neurologically asymptomatic adults with SCA vs healthy control individuals.

Placenta growth factor in sickle cell disease: association with hemolysis and inflammation.

Placenta growth factor (PlGF) is released by immature erythrocytes and is elevated in sickle cell disease (SCD). Previous data generated in vitro suggest that PlGF may play a role in the pathophysiology of SCD-associated pulmonary hypertension (PHT) by inducing the release of the vasoconstrictor, endothelin-1. In this cross-sectional study of 74 patients with SCD, we confirm that PlGF is significantly elevated in SCD compared with healthy control subjects.

Surgical and obstetric outcomes in adults with sickle cell disease.

Background: Sickle cell disease patients are more likely than the general population to undergo surgery and usually do so at a younger age. Female sickle cell disease patients also have special gynecological and obstetric issues related to their disease.

Methods: We collected data through standardized clinical report forms, patient interviews, and medical records from 509 adult sickle cell disease patients.

Fibronectin bridges monocytes and reticulocytes via integrin alpha4beta1.

Leucocytes are emerging as critical determinants in the severity of the pathology associated with sickle cell disease (SCD) and recent studies have shown that they can bind to sickle red blood cells (SS RBCs). However, the mechanism of this interaction is unclear. The alpha4beta1 integrin on monocytes and SS reticulocytes was found to mediate the interaction of these cells in in-vitro adhesion assays and in the blood of SCD patients.

Lack of Duffy antigen expression is associated with organ damage in patients with sickle cell disease.

Background: The Duffy glycoprotein (Fy) on red blood cells (RBCs) has been hypothesized to promote clearance of inflammatory cytokines, which may play a role in the pathogenesis of vasoocclusion in sickle cell disease (SCD). Persons with the African-type Fy(a-b-) phenotype--whose RBCs lack expression of Duffy--may less efficiently clear inflammatory cytokines. Therefore, the Duffy-negative genotype may be associated with more severe disease among patients with SCD.

Efficacy and safety of the Gardos channel blocker, senicapoc (ICA-17043), in patients with sickle cell anemia.

Senicapoc, a novel Gardos channel inhibitor, limits solute and water loss, thereby preserving sickle red blood cell (RBC) hydration. Because hemoglobin S polymerization is profoundly influenced by intracellular hemoglobin concentration, senicapoc could improve sickle RBC survival. In a 12-week, multicenter, phase 2, randomized, double-blind, dose-finding study, we evaluated senicapoc's safety and its effect on hemoglobin level and markers of RBC hemolysis in sickle cell anemia patients.

Identification of genetic polymorphisms associated with risk for pulmonary hypertension in sickle cell disease.

Up to 30% of adult patients with sickle cell disease (SCD) will develop pulmonary hypertension (pHTN), a complication associated with significant morbidity and mortality. To identify genetic factors that contribute to risk for pHTN in SCD, we performed association analysis with 297 single nucleotide polymorphisms (SNPs) in 49 candidate genes in patients with sickle cell anemia (Hb SS) who had been screened for pHTN by echocardiography (n = 111). Evidence of association was primarily identified for genes in the TGFbeta superfamily, including activin A receptor, type II-like 1 (ACVRL1), bone morphogenetic protein receptor 2 (BMPR2), and bone morphogenetic protein 6 (BMP6).

Coagulation activation and inflammation in sickle cell disease-associated pulmonary hypertension.

Background: Pulmonary hypertension (PHT) is common in sickle cell disease (SCD). The purpose of this study was to determine whether markers of coagulation activation and inflammation are associated with PHT in SCD.

Design And Methods: This cross-sectional study was performed using a cohort of patients followed at an adult Sickle Cell Clinic.

Phase I study of eptifibatide in patients with sickle cell anaemia.

The alphaIIbbeta3 antagonist eptifibatide is an effective treatment for patients with acute coronary syndromes (ACS). Platelet reactivity and CD40 ligand (CD40L) may play a role in the pathophysiology of sickle cell anaemia (SCA) similar to that in ACS, suggesting that inhibition of platelet aggregation and CD40L release by eptifibatide may benefit patients with SCA. Following eptifibatide infusion, safety and pharmacodynamic data were obtained from four SCA patients in their non-crisis, steady states.

Genetic polymorphisms associated with priapism in sickle cell disease.

Priapism occurs in 30-45% of male patients with sickle cell disease (SCD), but the possible influence of genetic risk factors on the incidence of priapism is not well understood. We examined genetic polymorphisms in 199 unrelated, adult (>18 years), male patients with Hb SS and Hb Sbeta(0)-thalassaemia, 83 (42%) of whom reported a history of priapism. Candidate genes for association with priapism were identified based on their involvement in adhesion, coagulation, inflammation and cell signalling.

Physical therapy alone compared with core decompression and physical therapy for femoral head osteonecrosis in sickle cell disease. Results of a multicenter study at a mean of three years after treatment.

Background: Osteonecrosis of the femoral head is a common complication in patients with sickle cell disease, and collapse of the femoral head occurs in 90% of patients within five years after the diagnosis of the osteonecrosis. However, the efficacy of hip core decompression to prevent the progression of osteonecrosis in these patients is still controversial.

Methods: In a prospective multicenter study, we evaluated the safety of hip core decompression and compared the results of decompression and physical therapy with those of physical therapy alone for the treatment of osteonecrosis of the femoral head in patients with sickle cell disease.

Dose-escalation study of ICA-17043 in patients with sickle cell disease.

Study Objective: To determine the dose tolerance, safety, and pharmacokinetics of a single oral dose of ICA-17043 in patients with sickle cell disease.

Design: Phase I, randomized, double-blind, placebo-controlled, single-dose, dose-escalation study.

Setting: Four university medical centers.

The Clinical Research Forum and Association of American Physicians disagree with criticism of the NIH Roadmap.

As representatives of 50 leading academic medical centers focusing on clinical research and many of academic medicine's scientific leaders, the Clinical Research Forum and Association of American Physicians disagree with the JCI's recent editorials on the NIH Roadmap, Elias Zerhouni's leadership, and the future directions of biomedical research.

Pulmonary hypertension in patients with sickle cell disease: a longitudinal study.

Unlabelled: Although pulmonary hypertension (PHT) is a common complication in patients with sickle cell disease (SCD), the rate of development of PHT and the factors that affect disease progression are unknown. We observed 93 patients over a median follow-up period of 2.6 years (range 0.

Biologically active CD40 ligand is elevated in sickle cell anemia: potential role for platelet-mediated inflammation.

Objective: After activation, platelets expose CD40 ligand (CD40L) on their surface, then subsequently release the inflammatory mediator as a soluble fragment (sCD40L). Because sickle cell anemia (SCA) is noted for both platelet activation and chronic inflammation, we asked whether platelet-released CD40L potentially plays a role in SCA.

Methods And Results: ELISAs demonstrate that SCA patient plasma contains 30-fold more sCD40L than control plasma.

The influence of renal function on hydroxyurea pharmacokinetics in adults with sickle cell disease.

This was an open-label, nonrandomized, 2-center study conducted to assess the influence of renal function on the pharmacokinetics of hydroxyurea in adults with sickle cell disease (SCD). Seventeen patients were divided into 5 groups: normal renal function (n = 7), mild renal impairment (n = 2), moderate renal impairment (n = 3), severe renal impairment (n = 2), and end-stage renal disease (ESRD, n = 3). Except for patients with ESRD, all the patients received a 15-mg/kg single oral dose of hydroxyurea.

Pulmonary hypertension in sickle cell disease.

Background: Recurrent vaso-occlusive episodes lead to progressive end-organ damage in patients with sickle cell disease. We sought to determine the prevalence of pulmonary hypertension in adult patients with sickle cell disease and to identify factors associated with this life-threatening complication.

Methods: Sixty patients (> or =18 years of age; mean [+/- SD] age, 37 +/- 13 years) followed at a University Medical Center were evaluated.

Mechanism of CD47-induced alpha4beta1 integrin activation and adhesion in sickle reticulocytes.

We recently reported that CD47 (integrin-associated protein) on sickle red blood cells (SS RBCs) activates G-protein-dependent signaling, which promotes cell adhesion to immobilized thrombospondin (TSP) under relevant shear stress. These data suggested that signal transduction in SS RBCs may contribute to the vaso-occlusive pathology observed in sickle cell disease. However, the CD47-activated SS RBC adhesion receptor(s) that mediated adhesion to immobilized TSP remained unknown.