Update on the use of hydroxyurea therapy in sickle cell disease. Blood. 2014;124:3850-3857; quiz 4004. [PMID: 25287707 DOI: 10.1182/blood-2014-08-435768]

Hydroxyurea therapy in adult Nigerian sickle cell disease: a monocentric survey on pattern of use, clinical effects and patient's compliance

BACKGROUND

The clinical prospects of hydroxyurea therapy in the management of sickle cell disease (SCD) require evaluation in the Nigerian setting to develop indigenous guidelines. This survey examines the pattern of hydroxyurea therapy, its clinico-haematologic benefits and safety profile in Nigerian SCD subjects.

METHODS

A cross sectional pilot survey was carried out among 60 adult SCD subjects over 3 months. Data on clinical phenotypes, relevant haematological parameters and details of hydroxyurea therapy were obtained using a structured questionnaire through an interview process and case file review.

RESULTS

The median age was 30 years. Thirty-four (56.7%) of the subjects are aware of hydroxyurea therapy in SCD. Twenty-four (40%) SCD patients had previously used hydroxyurea. Only 4 subjects were fully compliant. Reasons for non-compliance included poor knowledge and lack of funds. In particular, hydroxyurea reduced leucocyte count and increased mean red cell volume (MCV) in compliant subjects.

CONCLUSION

Hydroxyurea use is low among Nigerian SCD subjects despite its proven efficacy/clinical prospects in the developed nations. Large scale multicenter studies and clinical trials are needed to form a basis for developing standard local treatment protocol for its use.

Sickle Cell Disease: A Brief Update

Sickle cell disease (SCD) is an inherited monogenic disease characterized by misshapen red blood cells that causes vaso-occlusive disease, vasculopathy, and systemic inflammation. Approximately 300,000 infants are born per year with SCD globally. Acute, chronic, and acute-on-chronic complications contribute to end-organ damage and adversely affect quantity and quality of life. Hematopoietic stem cell transplantation is the only cure available today, but is not feasible for the vast majority of people suffering from SCD. Fortunately, new therapies are in late clinical trials and more are in the pipeline, offering hope for this unfortunate disease, which has increasing global burden.

Hydroxycarbamine: from an Old Drug Used in Malignant Hemopathies to a Current Standard in Sickle Cell Disease

While hydroxycarbamide (hydroxyurea, HU) has less and fewer indications in malignant hemopathies, it represents the only widely used drug which modifies sickle cell disease pathogenesis. Clinical experience with HU for patients with sickle cell disease has been accumulated over the past 25 years in Western countries. The review of the literature provides increasing support for safety and efficacy in both children and adults for reducing acute vaso-occlusive events including pain episodes and acute chest syndrome. No increased incidence of leukemia and teratogenicity was demonstrated. HU has become the standard-of-care for sickle cell anemia but remains underused. Barriers to its use should be identified and overcome.

Long-Term Engraftment and Fetal Globin Induction upon BCL11A Gene Editing in Bone-Marrow-Derived CD34+ Hematopoietic Stem and Progenitor Cells

To develop an effective and sustainable cell therapy for sickle cell disease (SCD), we investigated the feasibility of targeted disruption of the BCL11A gene, either within exon 2 or at the GATAA motif in the intronic erythroid-specific enhancer, using zinc finger nucleases in human bone marrow (BM) CD34⁺ hematopoietic stem and progenitor cells (HSPCs). Both targeting strategies upregulated fetal globin expression in erythroid cells to levels predicted to inhibit hemoglobin S polymerization. However, complete inactivation of BCL11A resulting from bi-allelic frameshift mutations in BCL11A exon 2 adversely affected erythroid enucleation. In contrast, bi-allelic disruption of the GATAA motif in the erythroid enhancer of BCL11A did not negatively impact enucleation. Furthermore, BCL11A exon 2-edited BM-CD34⁺ cells demonstrated a significantly reduced engraftment potential in immunodeficient mice. Such an adverse effect on HSPC function was not observed upon BCL11A erythroid-enhancer GATAA motif editing, because enhancer-edited CD34⁺ cells achieved robust long-term engraftment and gave rise to erythroid cells with elevated levels of fetal globin expression when chimeric BM was cultured ex vivo. Altogether, our results support further clinical development of the BCL11A erythroid-specific enhancer editing in BM-CD34⁺ HSPCs as an autologous stem cell therapy in SCD patients.

Oral Monomethyl Fumarate Therapy Ameliorates Retinopathy in a Humanized Mouse Model of Sickle Cell Disease

AIMS

Sickle retinopathy (SR) is a major cause of blindness in sickle cell disease (SCD). The genetic mutation responsible for SCD is known, however; oxidative stress and inflammation also figure prominently in the development and progression of pathology. Development of therapies for SR is hampered by the lack of (a) animal models that accurately recapitulate human SR and (b) strategies for noninvasive yet effective retinal drug delivery. This study addressed both issues by validating the Townes humanized SCD mouse as a model of SR and demonstrating the efficacy of oral administration of the antioxidant fumaric acid ester monomethyl fumarate (MMF) in the disease.

RESULTS

In vivo ophthalmic imaging, electroretinography, and postmortem histological RNA and protein analyses were used to monitor retinal health and function in normal (HbAA) and sickle (HbSS) hemoglobin-producing mice over a one-year period and in additional HbAA and HbSS mice treated with MMF (15 mg/ml) for 5 months. Functional and morphological abnormalities and molecular hallmarks of oxidative stress/inflammation were evident early in HbSS retinas and increased in number and severity with age. Treatment with MMF, a known inducer of Nrf2, induced γ-globin expression and fetal hemoglobin production, improved hematological profiles, and ameliorated SR-related pathology. Innovation and Conclusion: United States Food and Drug Administration-approved formulations in which MMF is the primary bioactive ingredient are currently available to treat multiple sclerosis; such drugs may be effective for treatment of ocular and systemic complications of SCD, and given the pleiotropic effects, other nonsickle-related diseases in which oxidative stress, inflammation, and retinal vascular pathology figure prominently. Antioxid. Redox Signal. 25, 921-935.

Potential of Three Ethnomedicinal Plants as Antisickling Agents

Sickle cell disease (SCD) is a genetic blood disorder that affects the shape and transportation of red blood cells (RBCs) in blood vessels, leading to various clinical complications. Many drugs that are available for treating the disease are insufficiently effective, toxic, or too expensive. Therefore, there is a pressing need for safe, effective, and inexpensive therapeutic agents from indigenous plants used in ethnomedicines. The potential of aqueous extracts of Cajanus cajan leaf and seed, Zanthoxylum zanthoxyloides leaf, and Carica papaya leaf in sickle cell disease management was investigated in vitro using freshly prepared 2% sodium metabisulfite for sickling induction. The results indicated that the percentage of sickled cells, which was initially 91.6% in the control, was reduced to 29.3%, 41.7%, 32.8%, 38.2%, 47.6%, in the presence of hydroxyurea, C. cajan seed, C. cajan leaf, Z. zanthoxyloides leaf, and C. papaya leaf extracts, respectively, where the rate of polymerization inhibition was 6.5, 5.9, 8.0, 6.6, and 6.0 (×10^-2) accordingly. It was also found that the RBC resistance to hemolysis was increased in the presence of the tested agents as indicated by the reduction of the percentage of hemolyzed cells from 100% to 0%. The phytochemical screening results indicated the presence of important phytochemicals including tannins, saponins, alkaloids, flavonoids, and glycosides in all the plant extracts. Finally, gas chromatography-mass spectrometry analysis showed the presence of important secondary metabolites in the plants. These results suggest that the plant extracts have some potential to be used as alternative antisickling therapy to hydroxyurea in SCD management.

Hydroxyurea Treatment and Development of the Rat Cerebellum: Effects on the Neurogenetic Profiles and Settled Patterns of Purkinje Cells and Deep Cerebellar Nuclei Neurons

The current paper analyzes the development of the male and female rat cerebellum exposed to hydroxyurea (HU) (300 or 600 mg/kg) as embryo and collected at postnatal day 90. Our study reveals that the administration of this drug compromises neither the cytoarchitecture of the cerebellar cortex nor deep nuclei (DCN). However, in comparison with the saline group, we observed that several cerebellar parameters were lower in the HU injected groups. These parameters included area of the cerebellum, cerebellar cortex length, molecular layer area, Purkinje cell number, granule cell counts, internal granular layer, white matter and cerebellar nuclei areas, and number of deep cerebellar nuclei neurons. These features were larger in the rats injected with saline, smaller in those exposed to 300 mg/kg of HU and smallest in the group receiving 600 mg/kg of this agent. No sex differences in the effect of the HU were observed. In addition, we infer the neurogenetic timetables and the neurogenetic gradients of PCs and DCN neurons in rats exposed to either saline or HU as embryos. For this purpose, 5-bromo-2'-deoxyuridine was injected into pregnant rats previously administered with saline or HU. This thymidine analog was administered following a progressively delayed cumulative labeling method. The data presented here show that systematic differences exist in the pattern of neurogenesis and in the spatial location of cerebellar neurons between rats injected with saline or HU. No sex differences in the effect of the HU were observed. These findings have implications for the administration of this compound to women in gestation as the effects of HU on the development of the cerebellum might persist throughout their offsprings' life.

Novel Use of Hydroxyurea in an African Region With Malaria: Protocol for a Randomized Controlled Clinical Trial

BACKGROUND

Sickle cell anemia (SCA), one of most prevalent monogenic diseases worldwide, is caused by a glutamic acid to valine substitution on the beta globin protein of hemoglobin, which leads to hemolytic anemia. Hydroxyurea, the only disease-modifying therapy approved by the Food and Drug Administration for SCA, has proven to be a viable therapeutic option for SCA patients in resource-rich settings, given clinical improvements experienced while taking the medication and its once-daily oral dosing. Significant studies have demonstrated its safety and clinical efficacy among children and adults in developed countries. In Sub-Saharan Africa, however, the risk of malaria, hematologic toxicities, and safety of hydroxyurea in children with SCA living in malaria-endemic areas are unknown.

OBJECTIVES

Study objectives include determining the incidence of malaria in SCA patients taking hydroxyurea versus placebo; establishing the frequency of hematologic toxicities and adverse events (AEs) in children with SCA treated with hydroxyurea versus placebo; and defining the relationships between hydroxyurea treatment and fetal hemoglobin, soluble intracellular adhesion molecule-1, and nitric oxide levels, and between levels of these factors and risk of subsequent malaria.

METHODS

Novel use Of Hydroxyurea in an African Region with Malaria (NOHARM, NCT01976416) is a prospective, randomized, placebo-controlled, double-blinded phase III trial to compare risk of malaria with oral hydroxyurea versus placebo. Children will be recruited from the Mulago Hospital Sickle Cell Clinic in Kampala, Uganda.

RESULTS

Two hundred Ugandan children aged between 1.00 and 3.99 years with confirmed SCA will be randomized into treatment groups by order of entry in the study, based on a predetermined blinded randomization list. The primary outcome of the trial is malaria incidence in the 2 study groups, defined as episodes of clinical malaria occurring over the 1-year randomized study treatment period.

CONCLUSION

NOHARM will be the first prospective randomized, placebo-controlled clinical trial investigating the use of hydroxyurea for children with SCA in a malaria-endemic region within Africa. The results of this trial have the potential to significantly advance understanding of how to safely and effectively use hydroxyurea in children with SCA in malaria-endemic areas.

TRIAL REGISTRATION

Clinicaltrials.gov NCT01976416; https://clinicaltrials.gov/ct2/show/NCT01976416 (Archived by WebCite at http://www.webcitation.org/6hmoilZnp).

Adherence to hydroxyurea medication by children with sickle cell disease (SCD) using an electronic device: a feasibility study

Adherence to hydroxyurea (HU) is a significant modifying factor in sickle cell vaso-occlusive pain. We conducted a study using an electronic medication container-monitor-reminder device (GlowCap™) to track adherence and determine whether use of this device affected rates of HU adherence. Subjects were regular attendees to our clinic. They were given a 37-item questionnaire and were asked to use a GlowCap containing HU. When the device cap is opened, it makes a remote "medication taken" record. The device also provides usage reminder in the form of lights and alarm sounds if the cap opening is delayed. Nineteen subjects participated in the survey, and 17 in the intervention phase. Of the 17, 12 had reliable adherence data. Seventeen caregivers of patients and two patients completed the survey. Two most common barriers to adherence identified were lack of reminders and absence of medicine home delivery. The intervention component of this study, which used both the electronic (GlowCap) method and medication possession ratio showed that the median adherence rate for the 12 patients evaluated was 85 %. The GlowCap device accurately kept a record of adherence rates. This device may be an effective tool for increasing HU medication adherence.

Minireview: Prognostic factors and the response to hydroxurea treatment in sickle cell disease

This review describes current considerations in the use of hydroxyurea for the management of sickle cell disease in the context of clinical severity. Randomized trials of hydroxyurea have generally enrolled subjects with increased severity based on frequent vaso-occlusive events. An exception was the BABY HUG study in infants which documented substantial benefit even for asymptomatic subjects. Increasing data indicate that hydroxyurea has a substantial effect on reducing mortality in both adults and children-perhaps the most compelling reason for advocating the drug's widespread use. Although the efficacy of hydroxyurea is mediated primarily through increased erythrocyte fetal hemoglobin and much has been learned about the genomic influences on fetal hemoglobin levels in sickle cell disease, our ability to predict the fetal hemoglobin response to hydroxyurea remains limited; much more work in this area is indicated. The review is concluded with the recommendations of the 2014 NIH Evidence-Based Management of Sickle Cell Disease Expert Panel Report.

Optimal therapy for polycythemia vera and essential thrombocythemia: Preferred use of interferon therapy based on phase 2 trials

OBJECTIVES

To determine the value of recombinant interferon-alfa (rIFNα) in the treatment of polycythemia vera (PV) and essential thrombocythemia (ET) based on its biological activities and phase 2 clinical studies, pending completion of phase 3 trials; to determine importance of the Internet in patient decision-making in treatment selection.

RESULTS

The value of rIFNα in PV and ET is based upon its biological effects on PV stem cells and megakaryocyte proliferation. Single-arm trials are useful for life-threatening diseases when there are relatively few patients to evaluate endpoints, such as rIFNα treatment of PV and ET. Proper diagnostic criteria are mandatory; for PV, the current World Health Organization criteria emphasizing increased hemoglobin values exclude approximately one-third of eligible patients. Importance of these data: Single-arm studies in diseases exemplified by rIFNα in PV require updated diagnostic criteria for research and for clinical practice. The influence of the Internet on patient decisions for treatment is noteworthy.

CONCLUSION

The biologic basis for selecting therapy is exemplified by rIFNα in treating PV and ET. Current single-arm studies of rIFNα in PV and ET are relevant and acceptable. The importance of the Internet in patient decision-making is important.

Folate supplementation in people with sickle cell disease

BACKGROUND

Sickle cell disease is a group of disorders that affects haemoglobin, which causes distorted sickle- or crescent-shaped red blood cells. It is characterized by anaemia, increased susceptibility to infections and episodes of pain. The disease is acquired by inheriting abnormal genes from both parents, the combination giving rise to different forms of the disease. Due to increased erythropoiesis in people with sickle cell disease, it is hypothesized that they are at an increased risk for folate deficiency. For this reason, children and adults with sickle cell disease, particularly those with sickle cell anaemia, commonly take 1 mg of folic acid orally every day on the premise that this will replace depleted folate stores and reduce the symptoms of anaemia. It is thus important to evaluate the role of folate supplementation in treating sickle cell disease.

OBJECTIVES

To analyse the efficacy and possible adverse effects of folate supplementation (folate occurring naturally in foods, provided as fortified foods or additional supplements such as tablets) in people with sickle cell disease.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group's Haemoglobinopathies Trials Register comprising references identified from comprehensive electronic database searches and handsearches of relevant journals and abstract books of conference proceedings. We also conducted additional searches in both electronic databases and clinical trial registries.Date of last search: 07 December 2015.

SELECTION CRITERIA

Randomised, placebo-controlled trials of folate supplementation for sickle cell disease.

DATA COLLECTION AND ANALYSIS

Four review authors assessed the eligibility and risk of bias of the included trials and extracted and analysed the data included in the review. We used the standard Cochrane-defined methodological procedures.

MAIN RESULTS

One trial, undertaken in 1983, was eligible for inclusion in the review. This was a double-blind placebo-controlled quasi-randomised triaI of supplementation of folic acid in people with sickle cell disease. A total of 117 children with homozygous sickle cell (SS) disease aged six months to four years of age participated over a one-year period (analysis was restricted to 115 children).Serum folate measures, obtained after trial entry at six and 12 months, were available in 80 of 115 (70%) participants. There were significant differences between the folic acid and placebo groups with regards to serum folate values above 18 µg/l and values below 5 µg/l. In the folic acid group, values above 18 µg/l were observed in 33 of 41 (81 %) compared to six of 39 (15%) participants in the placebo (calcium lactate) group. Additionally, there were no participants in the folic acid group with serum folate levels below 5 µg/l, whereas in the placebo group, 15 of 39 (39%) participants had levels below this threshold. Haematological indices were measured in 100 of 115 (87%) participants at baseline and at one year. After adjusting for sex and age group, the investigators reported no significant differences between the trial groups with regards to total haemoglobin concentrations, either at baseline or at one year. It is important to note that none of the raw data for the outcomes listed above were available for analysis.The proportions of participants who experienced certain clinical events were analysed in all 115 participants, for which raw data were available. There were no statistically significant differences noted; however, the trial was not powered to investigate differences between the folic acid and placebo groups with regards to: minor infections, risk ratio 0.99 (95% confidence interval 0.85 to 1.15); major infections, risk ratio 0.89 (95% confidence interval 0.47 to 1.66); dactylitis, risk ratio 0.67 (95% confidence interval 0.35 to 1.27); acute splenic sequestration, risk ratio 1.07 (95% confidence interval 0.44 to 2.57); or episodes of pain, risk ratio 1.16 (95% confidence interval 0.70 to 1.92). However, the investigators reported a higher proportion of repeat dactylitis episodes in the placebo group, with two or more attacks occurring in 10 of 56 participants compared to two of 59 in the folic acid group (P < 0.05).Growth, determined by height-for-age and weight-for-age, as well as height and growth velocity, was measured in 103 of the 115 participants (90%), for which raw data were not available. The investigators reported no significant differences in growth between the two groups.The trial had a high risk of bias with regards to random sequence generation and incomplete outcome data. There was an unclear risk of bias in relation to allocation concealment, outcome assessment, and selective reporting. Finally, There was a low risk of bias with regards to blinding of participants and personnel. Overall the quality of the evidence in the review was low.There were no trials identified for other eligible comparisons, namely: folate supplementation (fortified foods and physical supplementation with tablets) versus placebo; folate supplementation (naturally occurring in diet) versus placebo; folate supplementation (fortified foods and physical supplementation with tablets) versus folate supplementation (naturally occurring in diet).

AUTHORS' CONCLUSIONS

One doubIe-blind, placebo-controlled triaI on folic acid supplementation in children with sickle cell disease was included in the review. Overall, the trial presented mixed evidence on the review's outcomes. No trials in adults were identified. With the limited evidence provided, we conclude that, while it is possible that folic acid supplementation may increase serum folate levels, the effect of supplementation on anaemia and any symptoms of anaemia remains unclear.Further trials may add evidence regarding the efficacy of folate supplementation. Future trials should assess clinical outcomes such as folate concentration, haemoglobin concentration, adverse effects and benefits of the intervention, especially with regards to sickle cell disease-related morbidity. Trials should include people with sickle cell disease of all ages and both sexes, in any setting. To investigate the effects of folate supplementation, trials should recruit more participants and be of longer duration, with long-term follow up, than the trial currently included in this review.

Novel insights in the management of sickle cell disease in childhood

Sickle cell disease (SCD) is a life-threatening genetic disorder characterized by chronic hemolytic anemia, vascular injury and multiorgan dysfunctions. Over the last few decades, there have been significant improvements in SCD management in Western countries, especially in pediatric population. An early onset of prophylaxis with Penicillin and a proper treatment of the infections have increased the overall survival in childhood. Nevertheless, management of painful episodes and prevention of organ damage are still challenging and more efforts are needed to better understand the mechanisms behind the development of chronic organ damages. Hydroxyurea (Hydroxycarbamide, HU), the only medication approved as a disease-modifying agent by the United States Food and Drug Administration and the European Medicines Agency, is usually under-used, especially in developing countries. Currently, hematopoietic stem-cell transplantation is considered the only curative option, although its use is limited by lack of donors and transplant-related toxicity. SCD symptoms are similar in children and adults, but complications and systemic organ damages increase with age, leading to early mortality worldwide. Experts in comprehensive care of young patients with SCD, especially those approaching the transition age to adulthood, are missing, leading people to rely on urgent care, increasing health care utilization costs and inappropriate treatments. It would be important to establish programs of comprehensive healthcare for patients with SCD from birth to adulthood, to improve their quality and expectancy of life.

Effects of hydroxyurea treatment for patients with hemoglobin SC disease

Although hemoglobin SC (HbSC) disease is usually considered less severe than sickle cell anemia (SCA), which includes HbSS and HbS/β(0) -thalassemia genotypes, many patients with HbSC experience severe disease complications, including vaso-occlusive pain, acute chest syndrome, avascular necrosis, retinopathy, and poor quality of life. Fully 20 years after the clinical and laboratory efficacy of hydroxyurea was proven in adult SCA patients, the safety and utility of hydroxyurea treatment for HbSC patients remain unclear. Recent NHLBI evidence-based guidelines highlight this as a critical knowledge gap, noting HbSC accounts for ∼30% of sickle cell patients within the United States. To date, only 5 publications have reported short-term, incomplete, or conflicting laboratory and clinical outcomes of hydroxyurea treatment in a total of 71 adults and children with HbSC. We now report on a cohort of 133 adult and pediatric HbSC patients who received hydroxyurea, typically for recurrent vaso-occlusive pain. Hydroxyurea treatment was associated with a stable hemoglobin concentration; increased fetal hemoglobin (HbF) and mean corpuscular volume (MCV); and reduced white blood cell count (WBC), absolute neutrophil count (ANC), and absolute reticulocyte count (ARC). Reversible cytopenias occurred in 22% of patients, primarily neutropenia and thrombocytopenia. Painful events were reduced with hydroxyurea, more in patients >15 years old. These multicenter data support the safety and potentially salutary effects of hydroxyurea treatment for HbSC disease; however, a multicenter, placebo-controlled, Phase 3 clinical trial is needed to determine if hydroxyurea therapy has efficacy for patients with HbSC disease.

Pomalidomide reverses γ-globin silencing through the transcriptional reprogramming of adult hematopoietic progenitors

Current therapeutic strategies for sickle cell anemia are aimed at reactivating fetal hemoglobin. Pomalidomide, a third-generation immunomodulatory drug, was proposed to induce fetal hemoglobin production by an unknown mechanism. Here, we report that pomalidomide induced a fetal-like erythroid differentiation program, leading to a reversion of γ-globin silencing in adult human erythroblasts. Pomalidomide acted early by transiently delaying erythropoiesis at the burst-forming unit-erythroid/colony-forming unit-erythroid transition, but without affecting terminal differentiation. Further, the transcription networks involved in γ-globin repression were selectively and differentially affected by pomalidomide including BCL11A, SOX6, IKZF1, KLF1, and LSD1. IKAROS (IKZF1), a known target of pomalidomide, was degraded by the proteasome, but was not the key effector of this program, because genetic ablation of IKZF1 did not phenocopy pomalidomide treatment. Notably, the pomalidomide-induced reprogramming was conserved in hematopoietic progenitors from individuals with sickle cell anemia. Moreover, multiple myeloma patients treated with pomalidomide demonstrated increased in vivo γ-globin levels in their erythrocytes. Together, these data reveal the molecular mechanisms by which pomalidomide reactivates fetal hemoglobin, reinforcing its potential as a treatment for patients with β-hemoglobinopathies.

2015 Clinical trials update in sickle cell anemia

Polymerization of HbS and cell sickling are the prime pathophysiological events in sickle cell disease (SCD). Over the last 30 years, a substantial understanding at the molecular level has been acquired on how a single amino acid change in the structure of the beta chain of hemoglobin leads to the explosive growth of the HbS polymer and the associated changes in red cell morphology. O2 tension and intracellular HbS concentration are the primary molecular drivers of this process, and are obvious targets for developing new therapies. However, polymerization and sickling are driving a complex network of associated cellular changes inside and outside of the erythrocyte, which become essential components of the inflammatory vasculopathy and result in a large range of potential acute and chronic organ damages. In these areas, a multitude of new targets for therapeutic developments have emerged, with several ongoing or planned new therapeutic interventions. This review outlines the key points of SCD pathophysiology as they relate to the development of new therapies, both at the pre-clinical and clinical levels.

Hydroxyurea: Clinical and Hematological Effects in Patients With Sickle Cell Anemia

Background and Aim:

It is well known that hydroxyurea impacts on clinical and hematologic indices in sickle cell disease (SCD), we aimed to evaluate the effect of hydroxyurea on clinical and hematological improvement of sickle cell anemia.

Methods and Materials:

In this cohort study 48 patients with sickle cell disease were enrolled and pain crisis, severity of pain, acute chest syndrome, the number of hospitalization, the rate of transfusion, spleen size, total Hb, HbF levels, MCV, MCH were compared before and after treatment with HU 10 mg/kg/day/for one year.

Results:

In patients with Sickle cell disease Hu significantly decreased the rate of transfusion, hospitalization, spleen size and significantly increased Hb, RBC indices and HbF. Furthermore, we did not find any remarkable adverse effect related to HU during the one year follow up in patients.

Conclusion:

We demonstrated that in the course of one year hydroxyurea 10 mg/kg/day can significantly increase HbF, total hemoglobin and RBC indices without any notable side effect in patients with SCD.

Genomic approaches to identifying targets for treating β hemoglobinopathies

Sickle cell disease and β thalassemia are common severe diseases with little effective pathophysiologically-based treatment. Their phenotypic heterogeneity prompted genomic approaches to identify modifiers that ultimately might be exploited therapeutically. Fetal hemoglobin (HbF) is the major modulator of the phenotype of the β hemoglobinopathies. HbF inhibits deoxyHbS polymerization and in β thalassemia compensates for the reduction of HbA. The major success of genomics has been a better understanding the genetic regulation of HbF by identifying the major quantitative trait loci for this trait. If the targets identified can lead to means of increasing HbF to therapeutic levels in sufficient numbers of sickle or β-thalassemia erythrocytes, the pathophysiology of these diseases would be reversed. The availability of new target loci, high-throughput drug screening, and recent advances in genome editing provide the opportunity for new approaches to therapeutically increasing HbF production.

Family caregiving for adults with sickle cell disease and extremely high hospital use

This study investigated coping with chronic illness in the adult patient-caregiver relationship for sickle cell disease, marked by debilitating acute and chronic pain. One-on-one interviews (N = 16) were conducted with eight primary caregivers of eight adults with extremely high hospital use, severe sickle cell disease with hospital admissions several times monthly over successive years. Caregivers were predominantly parents; two were romantic partners. Caregivers attributed disruptions to the disease's variability, tensions in how much support to give, and adults' inability to fulfill parental obligations. Both groups expressed fears of patients' increasing age, declining health, and early death. Targeted counseling and resilience training is recommended.