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Central nervous system (CNS) injury is common in sickle cell disease (SCD) and occurs early in life. Hydroxyurea is safe and efficacious for treatment of SCD, but high-quality evidence from randomized trials to estimate its neuroprotective effect is scant. HU Prevent was a randomized (1:1), double-blind, phase II feasibility/pilot trial of dose-escalated hydroxyurea vs. placebo for the primary prevention of CNS injury in children with HbSS or HbS-β 0 -thalassemia subtypes of SCD age 12-48 months with normal neurological examination, MRI of the brain, and cerebral blood flow velocity. We hypothesized that hydroxyurea would reduce by 50% the incidence of CNS injury. Two outcomes were compared: primary-a composite of silent cerebral infarction, elevated cerebral blood flow velocity, transient ischemic attack, or stroke; secondary-a weighted score estimating the risk of suffering the consequences of stroke (the Stroke Consequences Risk Score-SCRS), based on the same outcome events. Six participants were randomized to each group. One participant in the hydroxyurea group had a primary outcome vs. four in the placebo group (incidence rate ratio [90% CI] 0.216 [0.009, 1.66], p = .2914) (~80% reduction in the hydroxyurea group). The mean SCRS score was 0.078 (SD 0.174) in the hydroxyurea group, 0.312 (SD 0.174) in the placebo group, p = .072, below the p-value of .10 often used to justify subsequent phase III investigations. Serious adverse events related to study procedures occurred in 3/41 MRIs performed, all related to sedation. These results suggest that hydroxyurea may have profound neuroprotective effect in children with SCD and support a definitive phase III study to encourage the early use of hydroxyurea in all infants with SCD., (© 2024 Wiley Periodicals LLC.)

Introduction: Sickle cell disease is an inherited disorder characterized by hemoglobin S polymerization leading to vaso-occlusion and hemolytic anemia. These result in a variety of pathological events, causing both acute and chronic complications. Millions around the world are affected by sickle cell disease with predominance in sub-Saharan Africa. Hydroxyurea was the first drug approved for use in sickle cell disease to reduce the occurrence of painful crises and blood transfusions in patients with frequent, moderate to severe painful crises., Areas Covered: With the development of new therapeutics, the role of hydroxyurea is evolving. This narrative review aims to provide clinical data, safety information, and supplementary evidence for the role of hydroxyurea in the current era of sickle cell disease. A comprehensive literature search of databases, including PubMed and Cochrane Library, was conducted from 1963 to 2024., Expert Opinion: Even though new medications have been approved for sickle cell disease, hydroxyurea remains the gold standard. Hydroxyurea is not only a disease modifier but it has additional clinical benefits, it is affordable, and its longevity has prompted expanded research in areas such as underutilization and pharmacogenomics. As the treatment landscape evolves, hydroxyurea's long-standing record of efficacy and safety continues to support its role as a key agent in disease management.

Background: Suboptimal medication adherence is common across youth with chronic health conditions and may contribute to health disparities and adverse health outcomes, especially in underserved communities., Methods: Using pharmacy prescription records and guided by the World Health Organization Multidimensional Adherence Model, we examined patient-, treatment-, and health system-related factors that may affect hydroxyurea adherence in 72 youth with sickle cell disease (SCD), 10-18 years who had participated in the multisite "Hydroxyurea Adherence for Personal Best in SCD" (HABIT) feasibility (6 months) and efficacy (12 months) trials. Pharmacy data were collected from the year prior to study entry through the duration of each trial. We also examined hydroxyurea dose at baseline, prescribing patterns (hydroxyurea formulation and dose prescribed), quantity of hydroxyurea dispensed, and number of daily capsules/tablets prescribed. Data were analyzed using descriptive statistics., Results: On average, youth were prescribed 1095 ± 402 mg hydroxyurea per day, requiring ingestion of 3 or more capsules for 39.4% of youth. Frequently identified potential barriers were complex medication regimens in which dose of hydroxyurea differed by day of week (47.2%); receipt of an inadequate (< 30 days) supply of hydroxyurea from the pharmacy ≥ 3 times during record collection period (29.2%); and prescription of hydroxyurea suspension suggesting problems swallowing capsules (22.2%). In this sample, most youth were exclusively prescribed 500 mg capsules (62.5%), which was associated with complex medication regimens (RR 3.0, 95% CI 1.4-6.7). Potential barriers were common, occurred at all levels and are potentially modifiable with targeted interventions at the treatment- and health system-related levels., (© 2024 Wiley Periodicals LLC.)

Hydroxyurea treatment for children with sickle cell anemia (SCA) is effective and life-saving. Stepwise escalation to maximum tolerated dose (MTD) provides optimal benefits, but is logistically challenging and time-consuming, especially in low-income countries where most people with SCA live. Model-informed precision dosing (MIPD) of hydroxyurea expedites MTD determination and improves outcomes compared with trial-and-error dose adjustments. HdxSim, a user-friendly, online, clinical decision support tool was developed to facilitate hydroxyurea MIPD and evaluated using real-world pharmacokinetic (PK) data. First-dose hydroxyurea PK profiles were analyzed from two clinical trial datasets (Hydroxyurea Study of Long-Term Effects (HUSTLE), NCT00305175 and Therapeutic Response Evaluation and Adherence Trial (TREAT), NCT02286154). Areas under the concentration-time curve (AUC) estimated by HdxSim were compared with those determined using traditional trapezoidal methodology and PK software (MWPharm-DOS). The doses predicted by HdxSim and MWPharm-DOS were compared with the observed clinical MTD. For HUSTLE participants, HdxSim accurately estimated hydroxyurea AUC compared with the trapezoidal method, with < 20% variance. The average (mean ± SD) AUC for TREAT participants estimated with HdxSim (68.6 ± 18.0 mg*hour/L) was lower than MWPharm-DOS (78.6 ± 20.7 mg*hour/L, P = 0.012), but the average recommended doses were not different (425 vs. 423 mg/day, P = 0.97). Moreover, HdxSim was non-inferior to MWPharm-DOS at predicting clinical MTD (absolute difference 3.9 ± 5.8 vs. 4.9 ± 8.2 mg/kg/day, P = 0.19). HdxSim accurately estimates hydroxyurea exposure and is noninferior to traditional PK approaches at predicting the clinical hydroxyurea MTD. Hydroxyurea dosing based on target exposure leads to improved outcomes in children with SCA, and has the potential to make PK-guided hydroxyurea dosing more accessible to this neglected population globally., (© 2023 The Authors. Clinical Pharmacology & Therapeutics © 2023 American Society for Clinical Pharmacology and Therapeutics.)

Background: Hydroxyurea remains underutilized in the pediatric sickle cell population despite its well-known efficacy in decreasing sickle cell complications and hospitalizations. Access to refills and liquid formulation remains a critical barrier to adherence to hydroxyurea regimens. This study was undertaken to determine the clinical impact of home-delivering compounded liquid hydroxyurea (LHU) to pediatric patients with sickle cell disease., Procedure/methods: A retrospective cohort study was conducted using electronic health records and pharmacy databases. Pediatric patients younger than 21 years of age at the time of hydroxyurea initiation from March 2016 to July 2020 who received compounded LHU from Boston Medical Center Pharmacy were included. The primary outcomes of the study were drug adherence (assessed by evaluating the proportion of days covered [PDC]), rates of acute care utilization before and after enrolling in the LHU delivery program., Results: The final cohort included 41 patients, showing a significant decrease in hospitalizations (p = .01) and acute chest syndrome episodes (p = .03) after the initiation of the LHU delivery program. In comparing hydroxyurea-naïve patients with those previously exposed to hydroxyurea, the latter group had lower hospitalization rates (p = .01), fewer vaso-occlusive event (VOE) episodes (p = .02), and fewer emergency department (ED) visits (p = .01). The median PDC value 1 year post initiation of LHU was 95., Conclusions: Home delivery of compounded LHU from the pharmacy to pediatric sickle cell disease patients improved access to hydroxyurea, and was linked to reduced hospitalizations and acute chest syndrome episodes. This advancement in cost savings and improved patient outcomes is a significant step forward in pediatric hematology. By overcoming access barriers, home delivery programs can greatly enhance outcomes among pediatric patients with sickle cell disease., (© 2024 Wiley Periodicals LLC.)

Nonmyeloablative, matched sibling donor hematopoietic stem cell transplantation with alemtuzumab/total body irradiation (TBI) conditioning is a curative therapy with low toxicity for adults with sickle cell disease (SCD). However, relatively low donor chimerism levels and graft rejection remain important challenges. We hypothesized that adding azathioprine/hydroxyurea preconditioning will improve donor chimerism levels and reduce graft failure rate. In this prospective cohort study, we enrolled consecutive adult patients with SCD undergoing matched sibling donor transplantation at the Amsterdam UMC. Patients received azathioprine 150 mg/day and hydroxyurea 25 mg/kg/day for 3 months prior to alemtuzumab 1 mg/kg and 300 cGy TBI conditioning. Twenty patients with SCD (median age 26 years [range 19-49], 13 females) were transplanted. Median follow-up was 46.0 months (IQR 21.8-57.9). One-year overall survival and event-free survival (graft failure or death) were both 95% (95% confidence interval 86-100). Mean donor myeloid and T-cell chimerism 1-year post-transplant were 95.2% (SD ±10.6) and 67.3% (±15.3), respectively. One patient (5%) experienced graft failure without autologous regeneration, resulting in infections and death. All other patients had a corrected SCD phenotype and were able to discontinue sirolimus. Three patients were successfully treated with alemtuzumab (1 mg/kg) after the transplant because of declining donor chimerism and cytopenias to revert impending graft rejection. Toxicity was mostly related to sirolimus and alemtuzumab. One patient developed steroid-responsive grade II intestinal acute graft-versus-host disease. Collectively, preconditioning with azathioprine/hydroxyurea prior to nonmyeloablative matched sibling donor transplantation resulted in excellent event-free survival and robust donor T-cell chimerism, enabling the successful withdrawal of sirolimus. ClinicalTrials.gov: NCT05249452., (© 2024 The Authors. American Journal of Hematology published by Wiley Periodicals LLC.)

Methemoglobinemia secondary to administration of hydroxyurea is only reported in veterinary medicine as a result of accidental ingestion of high doses, and once at therapeutic dose in human medicine. A 2.5-year-old female spayed mixed breed dog was presented for acute signs of neurologic disease and diagnosed with severe erythrocytosis without an identified underlying cause, leading to suspicion of polycythemia vera. The dog was managed with phlebotomies, supportive care, and administration of hydroxyurea. Within 2 h of administration of hydroxyurea (37 mg/kg) administration, respiratory distress with cyanosis, and methemoglobinemia developed. Signs resolved within 24 h but recurred after a second administration of lower dosage of hydroxyurea (17 mg/kg) 20 days later. The dog remained asymptomatic except for mild cyanosis but was humanely euthanized for lack of relevant improvement of signs of neurologic disease. This case report documents the repeated occurrence of methemoglobinemia in a dog after administration of hydroxyurea at therapeutic doses., (© 2024 The Author(s). Journal of Veterinary Internal Medicine published by Wiley Periodicals LLC on behalf of American College of Veterinary Internal Medicine.)

Ropeginterferon-alfa2b (ropegIFNα2b) is a long-acting IFN formulation with broad FDA/EMA approval as a therapy of polycythemia vera (PV) with no symptomatic splenomegaly. There is currently lack of information on the real-world patient selection, including the impact of local reimbursement policies, and drug management, particularly: type/timing of screening and follow-up tests; absolute/relative contraindications to therapy; ropegIFNα2b dose and combinations with hydroxyurea. As a sub-analysis of the PV-ARC retrospective study (NCT06134102), we here report our monocenter experience with ropegIFNα2b in the period from January 2021, corresponding to drug availability outside clinical trial, and December 2023. Among the 149 patients with EMA/FDA indication, only 55 (36.9%) met the local reimbursement criteria and 18 (12.1%) received ropegIFNα2b. Thanks to appropriate screening, relative/absolute contraindications to ropegIFNα2b were detected and managed in a multidisciplinary manner. Efficacy and safety of ropegIFNα2b was confirmed, with 3 cases of early molecular response. General use of low ropegIFNα2b dose, with frequent need for hydroxyurea combinations, was noted. This real-world experience suggests a significant impact of local regulations on drug prescription and the need for greater real-world data collection on ropegIFNα2b in PV patients. Also, it describes appropriate multidisciplinary screening and monitoring procedures during ropegIFNα2b therapy., (© 2024. The Author(s).)

Sickle cell disease (SCD) is an inherited blood disorder that affects approximately 100,000 Americans, primarily from underrepresented racial minority populations, and results in costly, multi-organ complications. Hydroxyurea, the primary disease-modifying therapy for SCD, is effective at reducing most complications; however, adherence to hydroxyurea remains suboptimal and is the primary barrier to clinical effectiveness. Video directly observed therapy (VDOT) has shown promise as an adherence-promoting intervention for hydroxyurea, yet previous VDOT trials were limited by high attrition from gaps in technology access, use of unvalidated adherence measures, and healthcare system limitations of delivering VDOT to patients. As such, we fostered a small business partnership to compare VDOT for hydroxyurea to attention control to address previous shortcomings, promote equitable trial participation, and maximize scalability. VDOT will be administered by Scene Health (formerly emocha Health) and adherence monitoring will be performed using a novel electronic adherence monitor developed to meet the unique needs of the target population. Adolescent and young adult patients as well as caregivers of younger patients (<11 years of age) will be recruited. In addition to visit incentives, all participants will be offered a smartphone with a data plan to ensure all participants have equal opportunity to complete study activities. The primary objectives of this pilot, multi-center, randomized controlled trial (RCT) are to assess retention and sustained engagement and to explore needs and preferences for longer-term adherence monitoring and interventions. This RCT is registered with the National Institutes of Health (NCT06264700). Findings will inform a future efficacy RCT applying VDOT to hydroxyurea to address adherence gaps and improve outcomes within this vulnerable population., Competing Interests: We have read the journal’s policy and the authors of this manuscript have the following competing interests: Sebastian Seiguer is the co-founder and CEO of Scene Health. Lauren Brown and Katie Munshaw are employed by Scene Health. Scene Health owns trademarks, copyright, trade secrets, and know-how related to its video Directly Observed Therapy, which is the intervention for this trial. In addition, Scene Health is collaborating with another small business, Impruvon Health, to develop the novel electronic adherence monitor that will be used in this study. Data from this trial may be used by Impruvon Health for future patent applications for that device. This does not alter our adherence to PLOS ONE policies on sharing data and materials., (Copyright: © 2024 Walden et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Consistent with studies showing a high prevalence of the Duffy null phenotype among healthy Black Americans, this retrospective study found that Duffy null was present in >75% of a young and contemporary cohort of children with sickle cell disease (SCD) in the United States. Despite the potential for this phenotype to impact absolute neutrophil counts, hydroxyurea (HU) dosing, and outcomes, it was not associated with being prescribed a lower HU dose or having increased acute SCD visits early in the HU treatment course. Future studies are needed to confirm these findings in older children with SCD., (© 2024 Wiley Periodicals LLC.)

Background: Realizing Effectiveness Across Continents with Hydroxyurea (REACH) is an open-label non-randomised trial of hydroxyurea (hydroxycarbamide) in children with sickle cell anaemia in sub-Saharan Africa. The short-term results of REACH on safety, feasibility, and effectiveness of hydroxyurea were published previously. In this paper we report results from extended hydroxyurea treatment in the REACH cohort up to 8 years., Methods: In this open-label, non-randomised, phase 1/2 trial, participants were recruited from four clinical sites in Kilifi, Kenya; Mbale, Uganda; Luanda, Angola; and Kinshasa, Democratic Republic of Congo. Eligible children were 1-10 years old with documented haemoglobin SS or haemoglobin Sβ zero thalassaemia, weighing at least 10 kg. Participants received fixed-dose hydroxyurea of 17.5 (±2.5) mg/kg per day for 6 months (fixed-dose phase), followed by 6 months of dose escalation (2·5-5·0 mg/kg increments every 8 weeks) as tolerated, up to 20-35 mg/kg per day (maximum tolerated dose; MTD), defined as mild myelosuppression. After the MTD was reached, hydroxyurea dosing was optimised for each participant on the basis of changes in bodyweight and laboratory values over time (MTD with optimisation phase). After completion of the first 12 months, children with an acceptable toxicity profile and favourable responses were given the opportunity to continue hydroxyurea until the age of 18 years. The safety and feasibility results after 3 years has been reported previously. Here, haematological responses, clinical events, and toxicity rates were compared across the dosing phases (fixed-dose hydroxyurea vs MTD with optimisation phase) as protocol-specified outcomes. REACH is registered on ClinicalTrials.gov (NCT01966731) and is ongoing., Findings: We enrolled 635 children between July 4, 2014, and Nov 11, 2016. 606 children were given hydroxyurea and 522 (86%; 266 [51%] boys and 256 [49%] girls) received treatment for a median of 93 months (IQR 84-97) with 4340 patient-years of treatment. The current (Oct 5, 2023) mean dose is 28·2 (SD 5·2) mg/kg per day with an increased mean haemoglobin concentration (7·3 [SD 1·1] g/dL at baseline to 8·5 [1·5] g/dL) and mean fetal haemoglobin level (10·9% [SD 6·8] to 23·3% [9·5]) and decreased absolute neutrophil count (6·8 [3·0] × 10 9 cells per L to 3·6 [2·2] × 10 9 cells per L). Incidence rate ratios (IRR) comparing MTD with fixed-dose hydroxyurea indicate decreased vaso-occlusive episodes (0·60; 95% CI 0·52-0·70; p<0·0001), acute chest syndrome events (0·21; 0·13-0·33; p<0·0001), recurrent stroke events (0·27; 0·07-1·06; p=0·061), malaria infections (0·58; 0·46-0·72; p<0·0001), non-malarial infections (0·52; 0·46-0·58; p<0·0001), serious adverse events (0·42; 0·27-0·67; p<0·0001), and death (0·70; 0·25-1·97; p=0·50). Dose-limiting toxicity rates were similar between the fixed-dose (24·1 per 100 patient-years) and MTD phases (23·2 per 100 patient-years; 0·97; 0·70-1·35; p=0·86). Grade 3 and 4 adverse events were infrequent (18·5 per 100 patient-years) and included malaria infection, non-malarial infections, vaso-occlusive pain, and acute chest syndrome. Serious adverse events were uncommon (3·6 per 100 patient-years) and included malaria infections, parvovirus-associated anaemia, sepsis, and stroke, with no treatment-related deaths., Interpretation: Hydroxyurea dose escalation to MTD with dose optimisation significantly improved clinical responses and treatment outcomes, without increasing toxicities in children with sickle cell anaemia in sub-Saharan Africa., Funding: US National Heart, Lung, and Blood Institute and Cincinnati Children's Research Foundation., Competing Interests: Declaration of interests REW receives hydroxyurea donations from Bristol Myers Squibb and Addmedica; research donations from Hemex Health; and serves as Medical Advisor to Nova Laboratories. BA served on the Medical Advisory Board for Global Blood Therapeutics, Pfizer, Agios, and Bluebird Bio and receives research support from Pfizer and Bluebird Bio. All other authors declare no competing interests., (Copyright © 2024 Elsevier Ltd. All rights reserved, including those for text and data mining, AI training, and similar technologies.)

Transfusion-dependent thalassemia (TDT) is a major public health concern in India, requiring regular transfusions for survival. There is also significant morbidity caused by iron overload and transfusion related infections. Novel therapies targeting fetal hemoglobin induction are the need of the hour in resource-poor institutions for patients where transplant is not feasible for various reasons. This single arm, non-randomised prospective trial evaluated the efficacy and safety of a combination of low dose thalidomide and hydroxyurea in TDT along with the impact on quality of life (QoL). It included 41 TDT patients, who failed a reasonable trial of hydroxyurea. Complete response (CR) was defined as transfusion independence and partial response (PR) denoted at least a 50% reduction in transfusion requirement. The rest were defined as non-responders (NR). The mean age of the cohort was 20.78 years (range 12-45 years). There were 13 males and 28 females. Nineteen (46.3%), 7 (17.1%), and 15 (36.6%) patients achieved CR, PR, and no response respectively. The overall response rate (CR + PR) was 63.4%. There was a significant increase in hemoglobin levels with decrement in transfusion burden and ferritin levels. There were no significant adverse reactions. No significant predictors of response were found including amongst genetic modifiers. It improved the health related QoL amongst responders. The combination of thalidomide and hydroxyurea appear safe and effective in the reduction in transfusion requirement of TDT patients. The judicious use of these drugs can improve the quality of life and pave the way for patients not eligible for a stem cell transplant.

Background: Despite advances in therapeutics for adverse-risk acute myeloid leukaemia (AML), overall survival remains poor, especially in refractory disease. Comprehensive tumour profiling and pre-clinical drug testing can identify effective personalised therapies., Case: We describe a case of ETV6-MECOM fusion-positive refractory AML, where molecular analysis and in vitro high throughput drug screening identified a tolerable, novel targeted therapy and provided rationale for avoiding what could have been a toxic treatment regimen. Ruxolitinib combined with hydroxyurea led to disease control and enhanced quality-of-life in a patient unsuitable for intensified chemotherapy or allogeneic stem cell transplantation., Conclusion: This case report demonstrates the feasibility and role of combination pre-clinical high throughput screening to aid decision making in high-risk leukaemia. It also demonstrates the role a JAK1/2 inhibitor can have in the palliative setting in select patients with AML., (© 2024 The Authors. Cancer Reports published by Wiley Periodicals LLC.)

Hydroxyurea reduces the frequency of vaso-occlusive complications, increases hemoglobin, and decreases mortality in sickle cell disease (SCD). Although current guidelines recommend escalation to maximum tolerated dose (MTD), the use of fixed low-dose hydroxyurea is common in low-resource countries. We conducted a systematic review and meta-analysis to evaluate the efficacy of escalated doses versus fixed low-dose of hydroxyurea in adults with SCD. Nine studies were included in the quantitative synthesis, four evaluating fixed low-dose and five evaluating escalated doses of hydroxyurea. Average daily doses of hydroxyurea in the fixed low-dose and escalated dose studies were ~10 and 22 mg/kg, respectively. There was no difference in the estimate of vaso-occlusive crisis rate between escalated and fixed low-dose studies (p = .73). The mean difference in hemoglobin from baseline to follow-up was greater for fixed low-dose than escalated dose studies (1.07 g/dL vs. 0.54 g/dL, p = .01). No difference was seen in the mean estimate of fetal hemoglobin. Despite limited eligible studies and substantial heterogeneity of effect between the studies for several outcomes, there appears to be clinical equipoise regarding the most appropriate hydroxyurea dosing regimen in adults with SCD. Controlled studies of hydroxyurea at MTD versus fixed low-dose in adults with SCD are required., (© 2023 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Little is known about cognitive impairment in patients with sickle cell disease in Africa. This study aimed to assess cognitive impairment and identify possible risk factors in patients with sickle cell disease in Egypt. This study was conducted at Cairo University Children Hospital. Patients with sickle cell disease, between ages of 6-20 years were enrolled. Cognitive ability was tested using the Stanford Binet intelligence quotient (IQ) test, fourth edition. Transcranial Doppler, magnetic resonance imaging and magnetic resonance angiography of the brain were performed within a week of the IQ test. Among the 40 enrolled patients, 55% had a Full Scale IQ at least 1 standard deviation below the mean, and 27.5% had an IQ 2 standard deviations below the mean. High lactate dehydrogenase was significantly associated with low IQ (p = 0.004). In univariate analyses, IQ was significantly correlated with older age (p = 0.025), high lactate dehydrogenase (p = 0.008) and older age at the start of hydroxyurea (p = 0.025). Impaired cognition is prevalent among sickle cell disease patients. Early initiation of hydroxyurea therapy, which should also reduce hemolysis and lactate dehydrogenase, may be a simple measure to preserve mental abilities in these patients., (© 2021. Japanese Society of Hematology.)

Excessive reactive oxygen species (ROS) contribute to damage of retinal cells and the development of retinal diseases including age-related macular degeneration (AMD). ROS result in increased metabolites of lipoxygenases (LOXs), which react with ROS to induce lipid peroxidation and may lead to ferroptosis. In this study, the effect of 5-LOX inhibition on alleviating ROS-induced cell death was evaluated using sodium iodate (NaIO 3 ) in the retinal pigment epithelium (RPE) cell line ARPE-19 and a mouse model investigating oxidative stress in AMD. We demonstrated that NaIO 3 induced cell death in the RPE cells through mechanisms including ferroptosis. Inhibition of 5-LOX with specific inhibitor, Zileuton, or siRNA knockdown of ALXO5 mitigated NaIO 3 -induced lipid peroxidation, mitochondrial damage, DNA impairment, and cell death in ARPE-19 cells. Additionally, in the mouse model, pretreatment with Zileuton reduced the NaIO 3 -induced lipid peroxidation of RPE cells, cell death in the photoreceptor layer of the retina, inflammatory responses, and degeneration of both the neuroretina and RPE monolayer cells. Our results suggest that 5-LOX plays a crucial role in ROS-induced cell death in the RPE and that regulating 5-LOX activity could be a useful approach to control ROS and ferroptosis-induced damage, which promote degeneration in retinal diseases., Competing Interests: The authors declare no conflict of interest., (Copyright © 2022 Jong-Jer Lee et al.)

Hydroxyurea is an antimetabolite drug that induces fetal haemoglobin in sickle cell disease. However, its clinical usefulness in β-thalassaemia is unproven. We conducted a randomised, double-blind, placebo-controlled clinical trial to evaluate the efficacy and safety of hydroxyurea in transfusion-dependent β-thalassaemia. Sixty patients were assigned 1:1 to oral hydroxyurea 10-20 mg/kg/day or placebo for 6 months by stratified block randomisation. Hydroxyurea treatment did not alter the blood transfusion volume overall. However, a significantly higher proportion of patients on hydroxyurea showed increases in fetal haemoglobin percentage (89% vs. 59%; p < 0.05) and reductions in erythropoietic stress as measured by soluble transferrin receptor concentration (79% vs. 40%; p < 0.05). Based on fetal haemoglobin induction (> 1.5%), 44% of patients were identified as hydroxyurea-responders. Hydroxyurea-responders, required significantly lower blood volume (77 ± SD27ml/kg) compared to hydroxyurea-non-responders (108 ± SD24ml/kg; p < 0.01) and placebo-receivers (102 ± 28ml/kg; p < 0.05). Response to hydroxyurea was significantly higher in patients with HbE β-thalassaemia genotype (50% vs. 0%; p < 0.01) and Xmn1 polymorphism of the γ-globin gene (67% vs. 27%; p < 0.05). We conclude that oral hydroxyurea increased fetal haemoglobin percentage and reduced erythropoietic stress of ineffective erythropoiesis in patients with transfusion-dependent β-thalassaemia. Hydroxyurea reduced the transfusion burden in approximately 40% of patients. Response to hydroxyurea was higher in patients with HbE β-thalassaemia genotype and Xmn1 polymorphism of the γ-globin gene., (© 2022. The Author(s).)

Aim : Endoplasmic reticulum-associated degradation (ERAD), which involves degradation of improperly folded proteins retained in the ER, is implicated in various diseases including chronic kidney disease. This study is aimed to determine the role of ERAD in Klotho deficiency of mice and human kidney tubular epithelial cells (HK-2) with renal interstitial fibrosis (RIF). Methods : Following establishment of a mouse RIF model by unilateral ureteral obstruction (UUO), a specific ERAD inhibitor, Eeyarestatin I (EerI), was administered to experimental animals by intraperitoneal injection. Serum and kidney samples were collected for analysis 10 days after operation. Soluble Klotho levels were measured by enzyme-linked immunosorbent assay, while the degree of kidney injury was assessed by renal histopathology. Renal Klotho expression was determined by quantitative real-time PCR, immunohistochemical and western blotting analyses. ERAD and unfolded protein response (UPR) were evaluated by detecting associated components such as Derlin-1, glucose-regulated protein 78 (GRP78), activating transcription factor 4 (ATF4) and protein disulfide isomerase (PDI). HK-2 cells were exposed to transforming growth factor (TGF)-β1 with or without EerI, and expressions of related proteins including Klotho, Derlin-1, GRP78, ATF4 and PDI were determined by western blotting analyses. Results : UUO induced severe kidney injuries and RIF. Klotho expression in both serum and kidney tissue was obviously downregulated, while Derlin-1 was notably upregulated, indicating that ERAD was activated to potentially degrade improperly folded Klotho protein in this model. Intriguingly, treatment with EerI led to significantly increased Klotho expression, especially soluble (functional) Klotho. Furthermore, specific inhibition of ERAD increased expression of GRP78, ATF4 and PDI compared with the UUO group. The consistent results in vitro were also obtained in TGF-β1-treated HK-2 cells exposed to EerI. These observations suggest that UPR was remarkably enhanced in the presence of ERAD inhibition and compensated for excess improperly folded proteins, subsequently contributing to the additional production of mature Klotho protein. Conclusion : ERAD is involved in Klotho deficiency in RIF and its specific inhibition significantly promoted Klotho expression, possibly through enhanced UPR. This may represent a novel regulatory mechanism and new therapeutic target for reversing Klotho deficiency., Competing Interests: Competing Interests: The authors have declared that no competing interest exists., (© The author(s).)

Carbohydrate polymers were widely used in pharmaceuticals and drug delivery systems due to their biodegradability and biocompatibility. Among them, chitosan (Cs) has been considered in many new drug delivery systems. Poly(ethylene glycol) as a hydrophilic polymer can increase the solubility and stealth functions of nanocarriers. The Fe 3 O 4 nanoparticles functionalized with polymers act as non-toxic drug vehicles for tumor targeting under external magnetic fields. In present study, the Fe 3 O 4 /SiO 2 -NH 2 nanoparticles were prepared and then functionalized with methoxy-PEGylated chitosan (Cs-g-mPEG2000) and the hydroxyurea (HU) was loaded on this nanoparticles. The structure, crystallinity, and morphology of HU/Fe 3 O 4 /SiO 2 /Cs-g-mPEG2000 were determined using spectroscopic and electron microscopy analysis. Encapsulation efficiency of HU and the percentage of loading and release rate at different pH values at 37 °C were examined. Maximum drug release was observed at pH = 7.4. According to TEM results, the nanoparticle sizes were between 18 and 157 nm. The cytotoxicity effect of HU-loaded nanoparticles against MCF-7 human breast cancer cell was evaluated using MTT assay and cell cycle arrest analysis. The inhibitory concentration (IC50) values were 249 and 85 μg/mL on the MCF-7 cell line compared to the control group in 24 h and 96 h, respectively. In addition, the expression of p53 and lincRNA-P21 genes in treated cells and control group was assessed using real-time PCR, and the results showed that the ratio of p53 expression to lincRNA-P21 in MCF-7 cells was significantly increased (P < 0.05). The cell cycle arrested in the S-phase and the population of cells increased 1.3-fold compared to the control group., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Despite high prevalence and incidence of β-thalassemia in Pakistan, there is very limited work on the use of hydroxyurea (HU) in thalassemia patients in the country. This is the first insight regarding genetic profiling of BCL11A and HU responses in Pakistani β-thalassemia. It correlates single-nucleotide polymorphisms on BCL11A (rs4671393, rs766432) and HBG2 (XmnI), age at first transfusion, and β-globin mutations with HU response in β-thalassemia major (BTM). Of 272 patients treated with HU, 98 were complete responders, 55 partial responders, and 119 nonresponders. Our analysis shows that HU response was significantly associated with patients having IVSI-1 or CD 30 mutation (P<0.001), age at first transfusion >1 year (P<0.001), and with the presence of XmnI polymorphism (P<0.001). The single-nucleotide polymorphisms of BCL11A were more prevalent among responders, but could not show significant association with HU response (P>0.05). Cumulative effect of all 5 predicting factors through simple binary scoring indicates that the likelihood of HU response increases with the number of primary and secondary genetic modifiers (P<0.001). Predictors scoring is a pragmatic tool to foresee HU response in patients with BTM. The authors recommend a score of ≥2 for starting HU therapy in Pakistani patients with BTM., Competing Interests: The authors declare no conflicts of interest., (Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.)

Hydroxyurea (hydroxycarbamide) (HU) for sickle cell anaemia (SCA) is underutilised. Case management is an evidence-based health management strategy and in this regard patient navigators (PNs) may provide case management for SCA. We hypothesised that HU-eligible patients exposed to PNs would have improved indicators of starting HU and HU adherence. We randomised 224 HU-eligible SCA adults into the Start Healing in Patients with Hydroxyurea (SHIP-HU) Trial. All patients received care from trained physicians using standardised HU prescribing protocols. Patients in the Experimental arm received case management and education from PNs through multiple contacts. All other patients were regarded as the Control arm and received specialty care alone. Study physicians were blinded to the study arms and did not interact with PNs. At baseline, 6 and 12 months we assessed and compared laboratory parameters and HU adherence indicators. Experimental patients had higher 6-month mean fetal haemoglobin (HbF) levels than controls. But at 12 months, mean HbF was similar, as were white blood cell count, absolute neutrophil count, total haemoglobin, platelet count and mean corpuscular volume. At 12 months there were fewer experimental patients missing HU doses than controls (mean 1·8 vs. 4·5, P = 0·0098), and more recent HU prescriptions filled than for controls (mean 53·8 vs. 92 days, median 27·5 vs. 62 days, P = 0·0082). Mean HU doses were largely similar. We detected behavioural improvements in HU adherence but no haematological improvements by adding PNs to specialty care., (© 2021 British Society for Haematology and John Wiley & Sons Ltd.)

Alpha haemoglobin-stabilising protein (AHSP) is a key chaperone synthesised in red blood cell (RBC) precursors. Many studies have reported AHSP as a potential biomarker of various diseases. AHSP gene expression has been studied in detail, but little is known about AHSP protein levels in RBCs. We investigated the AHSP concentration of RBC lysates from control subjects (n = 10) and patients with sickle cell anaemia (SCA) with (n = 10) and without (n = 12) hydroxycarbamide (HC) treatment, to evaluate the clinical relevance of AHSP in SCA. We developed a sandwich enzyme-linked immunosorbent assay method, with which we were able, for the first time, to determine the mean AHSP concentration in control RBC lysates (0·82 µg/ml). The AHSP concentration (2·23 µg/ml) was significantly higher in untreated patients with the SS genotype than in controls. The AHSP concentration decreased significantly on HC treatment (1·50 µg/ml) but remained significantly higher than that in controls. A strong positive correlation was observed between the AHSP concentration and the α-haemoglobin pool with the three groups of subjects pooled into a single group. Our present findings indicate that AHSP concentration can be considered a candidate biomarker for monitoring HC responses in patients with SCA and suggest a role for AHSP in various RBC diseases., (© 2021 British Society for Haematology and John Wiley & Sons Ltd.)

We used the Reach, Effectiveness, Adoption, Implementation, and Maintenance (RE-AIM) framework to evaluate a Stroke Prevention Team's readiness to prevent strokes in children with sickle cell anemia living in northern Nigeria. The NIH sponsored Stroke Prevention Trial in Nigeria included a goal of a sustainable stroke prevention program. The program's 1-year reach for transcranial Doppler screening was 14.7% (4710/32,000) of which 6.0% (281/4710) had abnormal velocities (≥200 cm/s). All participants with abnormal transcranial Doppler velocities were started on hydroxyurea (effectiveness). The leaders of all 5 hospitals agreed to adopt the program. After 1 year, program-implementation and maintenance rates were 100%, demonstrating the program's feasibility and short-term sustainability., Competing Interests: M.R.D.: had full access to all the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis. M.R.D.: designed the study. S.U.A. and M.A.T.: provided the TCD training. A.H.D., H.B.-M., H.I., A.T., A.A.S., B.W.J., S.G., Y.K., L.H., S.A., M.A.Z., and N.I.: administered the TCD screening. E.T. and L.J.: verified the neurological examinations. A.I.G., F.M.U., M.A.T., A.I.G., S.U.A., B.C.G., J.G., and D.L.G.: collected the data. D.L.G. and M.R.: performed the analyses. M.R.D., S.A., D.L.G., A.A.B., M.R.D.: interpreted the results. D.L.G., A.A.B., L.C.J., E.T., M.H.A., and M.R.D.: wrote the manuscript. Before submission, all authors reviewed the manuscript.The authors declare no conflict of interest., (Copyright © 2021 The Author(s). Published by Wolters Kluwer Health, Inc.)

Background: Hydroxyurea (HU) treatment of patients with essential thrombocythemia (ET), polycythemia vera (PV), and primary myelofibrosis (PMF) (MPNs) normalizes elevated blood cell counts within weeks in the large majority of patients. Studies on the impact of HU upon the kinetics of the JAK2V617F allele burden, leukocyte, and platelet counts over time are scarce., Purpose: Using data-driven analysis as a novel tool to model the kinetics of the JAK2V617F allele burden and blood cell counts over time during treatment with HU., Material and Methods: Using serial measurements of JAK2V617F and correlation analysis of routine hematological values (the Hb-concentration, leukocyte count, platelet count, and lactic dehydrogenase), we present a detailed description and analysis of the kinetics of the JAK2V617F, leukocyte, and platelet counts and lactic dehydrogenase in 27 patients (PV = 18; ET = 7; PMF = 2), who were followed in the Danish randomized trial (DALIAH). To further analyze the JAK2V617F kinetics, we use a machine learning clustering algorithm to group the response patterns., Results: Response patterns were highly heterogeneous, with clustering resulting in 3 groups and 3 outliers. In the large majority of patients, HU treatment was initially associated with a modest decline in the JAK2V617F allele burden in concert with a decline in leukocyte and platelet counts. However, HU did not induce a sustained and continuous decrease in the JAK2V617F allele burden., Conclusion: Using data-driven analysis of the JAK2V617F allele burden, leukocyte, and platelet kinetics during treatment with HU, we have shown that HU does not induce a sustained decrease in the JAK2V617F allele burden and neither induces sustained normalization of elevated cell counts in MPN patients. Our results may explain why MPN patients during treatment with HU still have a substantially increased risk of thrombosis., (© 2021 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Introduction : Hydroxyurea (HU) is an S-phase specific oral chemotherapeutic agent that inhibits ribonucleotide diphosphate reductase. It is the most common used cytoreductive drug in patients (pts) with BCR-ABL1 negative myeloproliferative neoplasms (MPN) and sickle cell disease (SCD). The World Health Organization lists HU as an "essential drug". Although most patients tolerate HU well, cutaneous adverse events (CAE) are frequent side effects and may limit its long-term use. This has become increasingly evident in recent years, especially in MPN patients, where CAE were previously underestimated and underdiagnosed. Areas covered : In this review, we present the available literature on HU-related CAE in MPN patients. In particular, data from a recently published and so far, only prospective non-interventional study investigating CAE in 172 MPN patients will be discussed in detail and compared with previously available data. Finally, we give an overview of the management of HU-related CAE in MPN patients and provide recommendations on the practical clinical approach. Expert opinion : In clinical practice, HU associated CAE are common and have important diagnostic and therapeutic consequences. Therefore, they should be considered in all MPN patients treated with HU in the future.

Neurocognitive impairment is common in sickle cell disease (SCD) and is associated with significant functional limitations. In a cross-sectional analysis, we examined the association between hydroxyurea (HU) treatment and neurocognitive functioning from school-age to young adulthood in individuals with SCD. A total of 215 patients with HbSS/HbSβ 0 -thalassaemia (71% HU treated) and 149 patients with HbSC/HbSβ + -thalassaemia (20% HU treated) completed neurocognitive measures at one of four developmental stages: school-age (age 8-9 years), early adolescence (age 12-13 years), late adolescence (age 16-17 years) and young adulthood (ages 19-24 years). For participants with multiple assessments, only the most recent evaluation was included. In multivariable analysis adjusted for social vulnerability, HU treatment and sex, older age was associated with a reduction in overall intelligence quotient (IQ) of 0·55 points per year of life [standard error (SE) = 0·18, false discovery rate adjusted P value (PFDR) = 0.01] for patients with HbSS/HbSβ 0 -thalassaemia. Earlier initiation of HU (n = 152) in HbSS/HbSβ 0 -thalassaemia was associated with higher scores on neurocognitive measures across most domains, including IQ [estimate (SE) 0·77 (0·25)/year, PFDR = 0·01], after adjusting for social vulnerability, sex and treatment duration. These results support the early use of HU to limit the detrimental neurocognitive effects of SCD, while highlighting the need for additional measures to further mitigate neurocognitive deterioration., (© 2021 British Society for Haematology and John Wiley & Sons Ltd.)

We describe a patient with leukemia undergoing chemotherapy who developed painful purpuric nodules of the digits. These findings were concerning for endocarditis (clinically) and angiokeratomas on gross histology. After extensive evaluation, we report the development of painful purpuric nodules as a likely side effect of the patient's therapeutic regimen (hydroxyurea, danorubicin, cytarabine, and methotrexate).

Hydroxyurea (hydroxycarbamide) is an effective treatment for sickle cell anaemia (SCA), but clinical responses depend primarily upon the degree of fetal haemoglobin (HbF) induction and the heterogeneity of HbF expression across erythrocytes. The number and characteristics of HbF-containing cells (F-cells) are not assessed by traditional HbF measurements. Conventional hydroxyurea dosing (e.g. fixed doses or low starting doses with stepwise escalation) produces a moderate heterocellular HbF induction, but haemolysis and clinical complications continue. Robust, pancellular HbF induction is needed to minimise or fully inhibit polymerisation of sickle haemoglobin. We treated children with hydroxyurea using an individualised, pharmacokinetics-guided regimen starting at predicted maximum tolerated dose (MTD). We observed sustained HbF induction (mean >30%) for up to 6 years, which was not dependent on genetic determinants of HbF expression. Nearly 70% of patients had ≥80% F-cells (near-pancellular), and almost half had ≥90% F-cells (pancellular). The mean HbF/F-cell content was ~12 pg. Earlier age of initiation and better medication adherence were associated with high F-cell responses. In summary, early initiation of hydroxyurea using pharmacokinetics-guided starting doses at predicted MTD can achieve sustained near-pancellular or pancellular HbF expression and should be considered an achievable goal for children with SCA treated with hydroxyurea at optimal doses. Clinical trial registration number: NCT02286154 (clinicaltrials.gov)., (© 2021 British Society for Haematology and John Wiley & Sons Ltd.)

Introduction: Beta-thalassemia is an autosomal recessive hereditary anemia characterized by reduced or absent β-globin chain synthesis, affecting about 60,000 people peryear. Management for β-thalassemia major includes regular blood transfusions followed by iron chelating therapy and drug targeting ineffective erythropoiesis. Areas covered: The safety of licensed drugs for the management of β-thalassemia is reviewed, using evidence from clinical trials and observational research. Such drugs include the iron chelators and the erythrocyte maturation agent luspatercept. The safety of emerging treatment, such as hydroxyurea and thalidomide is also reviewed. Expert opinion : Beta-thalassemia is arare disease, and is not surprising that there are limited studies investigating the safety of drugs used in this disease. Indeed, although observational studies are the main source of drug safety information in areal-world setting, only eleven studies were identified for iron-chelators and none of these estimated the risk of agiven safety outcome. Future work should aim to better leverage existing sources of real-world datato investigate drug safety in thalassemia.

Hydroxyurea is a chemotherapeutic agent used for myeloproliferative disorders and sickle cell anemia that is well known to cause painful mucocutaneous ulcers, typically involving the legs or mouth. However, genital ulcerations due to hydroxyurea therapy are a rare, and likely underrecognized, adverse effect with only a few cases reported in the literature to date. Ulcers of the lower legs caused by hydroxyurea are associated with a diagnostic delay, and this is likely exacerbated in cases of genital ulceration due to a lack of awareness. Herein we present two cases of painful genital ulceration in patients on hydroxyurea therapy. In the first Case, an 87 year-old male with polycythemia vera developed an ulcer on the scrotum, which was assessed initially through virtual visits during the COVID-19 pandemic, and was refractory to topical and oral antibiotic treatments. The second case was a 79 year-old male with essential thrombocythemia and a history of persistent leg ulcers who developed erosions of the glans penis. Both patients experienced complete resolution within weeks of discontinuing hydroxyurea therapy. In conclusion, genital ulcers and erosions induced by hydroxyrea may be underrecognized in clinical practice, but if identified, withdrawal of hydroxyurea leads to quick resolution of these lesions and the associated pain., (Copyright © 2021. Published by Elsevier Ltd.)

Background: Asthma is a chronic airway disorder with variable/recurring symptoms, airflow obstruction, bronchial hyperresponsiveness, and an inflammation. The expert panel report of the National Heart Lung and Blood Institute recommends asthma screening in sickle cell disease (SCD); however, specific approach is not mentioned. We hypothesize that the breathmobile case identification survey (BCIS) is a valid asthma screening tool in children with SCD. Methods: This prospective, single-center study enrolled 129 SCD patients aged 5 to 18 years from March 2016 to March 2018. All patients completed BCIS, spirometry, and fractional exhaled nitric oxide (FeNO). A single pulmonologist blinded to the BCIS results evaluated patients for asthma. Results: Asthma prevalence was 41%. Male gender (60.4%; p  = 0.041), allergic rhinitis (86.8%; p  < 0.01), hydroxyurea usage (73.6%; p  < 0.01), and family history of asthma (34%; p  < 0.01) were higher but not self-reported parental asthma history, eczema, and tobacco smoke exposure in the asthma group compared to the nonasthma group. FEV 1 ( p  = 0.003), FVC ( p  = 0.02), FEV 1 /FVC ( p  = 0.053), and FEF 25-75 % ( p  = 0.02) were lower in asthma. FeNO levels were comparable in both groups. The sensitivity, specificity, positive predictive value, and negative predictive value of the abbreviated BCIS were 67.3%, 90.8%, 83.3%, and 80.2% for asthma; and 82.1%, 90.8%, 76.7%, and 93.2% for persistent asthma, respectively. Persistent asthma patients had a trend of higher hydroxyurea use (82.8% vs. 58.3%; p  = 0.049) and tobacco smoke exposure (55.2% vs. 29.2%; p  = 0.057) compared to intermittent asthma. Conclusion: We have validated the BCIS to screen for asthma in SCD. Spirometry but not FeNO may support an asthma diagnosis.

Inflammation and oxidative stress play a key role in the pathophysiology of sickle cell disease (SCD). However, the potential influence of different sickle genotypes, or hydroxyurea (HU) treatment, on these factors remains poorly documented. The present study compared several plasma markers of inflammation and oxidative stress, as well as microvascular function, between patients with sickle SC disease (HbSC, n = 19) and patients with sickle cell anemia (HbSS) under hydroxyurea (HU) treatment (n = 16), or not (n = 13). Hemorheological parameters and levels of inflammatory (IL-6, IL-8, IFN-γ, MCP-1, MIP-1β, TNF-α) and oxidative stress (AOPP, MDA, MPO) markers were determined. Peripheral microcirculatory cutaneous blood flow and immediate microvascular response to local heat were evaluated using laser Doppler flowmetry. Oxidative stress and inflammation were lower in HbSC patients and HbSS patients under HU therapy compared to HbSS patients not treated with HU. Blood viscosity was higher in HbSC than in HbSS patients treated with or not with HU. Vasodilation response of the cutaneous microcirculation to heat stress was higher in HbSS patients receiving HU treatment. Our results clearly established that both sickle cell genotype and HU treatment modulate inflammation and oxidative stress., (© 2021 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Hydroxyurea (HU) and thalidomide have been reported to improve clinical and hematological parameters in transfusion-dependent beta thalassemia (TDT). Therefore, we retrospectively analyzed the combination of HU and thalidomide in 140 transplant ineligible TDT, ≥ 10 years old, visiting our thalassemia clinic between October 2014 and November 2019. Responses were defined as maintenance of hemoglobin ≥9gm/dl without transfusion as complete response (CR) and with at least 50% reduction in transfusion burden as partial response (PR). Patients with less than 50% transfusion burden reduction for consecutive 6 months of therapy were defined as non-responders (NR), and treatment was discontinued thereafter. Primary end point was overall response rate (ORR) at last follow-up. At median follow-up of 22.6 (95% CI 16.4-28.7) months, 76 (57.2%) patients achieved CR and 19 (14.3%) achieved PR, accounting to an ORR of 71.5%. Among responders at last follow-up, a significant increase in the post-treatment hemoglobin (0.88±0.37gm/dl, p<0.0001) and drop in serum ferritin (-1490.5ng/ml, p<0.0001) were observed. Median time to CR was 124 (95% CI 75.3-172.6) days. Median longest continuous CR was 791 (95% CI 662.2-919.7) days. Common toxicities observed were sedation (25%), hyperbilirubinemia {(23.57%, grade 3/4 =17 (12.14%)}, and constipation (22.8%). Nearly three-fourth of the patients has responded with majority having CR. Adverse events are a concern; hence, regular close monitoring is a prerequisite.

Background: Hydroxyurea is underutilized by sickle cell health-care providers in Nigeria despite available evidence of its effectiveness in reducing the manifestations and complications of sickle cell disease (SCD)., Objectives: To assess the level of utilization and provider-related barriers to the use of hydroxyurea in SCD therapy in Jos, Nigeria., Methods: A cross-sectional study conducted among 132 medical doctors providing care for SCD patients. Data on sociodemographics, utilization and barriers to hydroxyurea use were obtained. The barriers were fed cumulatively into the logistic regression model as predictors of utilization., Results: Of the 132 care providers, 88 (67%) had been in medical practice for ≥6years. The level of utilization of hydroxyurea was 24.2%. The significant barriers that predicted the non-utilization of hydroxyurea included lack of expertise (OR=5.1; 95% CI=2.65-9.05), lack of clinical guidelines (OR=3.84; 95% CI=2.37-14.33), fear of side-effects (OR=0.50; 95% CI=0.22-0.68) and doubt about its effectiveness (OR=0.30; 95% CI=0.20-0.90)., Conclusion: The level of utilization of hydroxyurea in the treatment of SCD among the care providers is sub-optimal with the lack of expertise in its use identified as the most prominent barrier. There is an urgent need for the training of sickle cell care-providers and the development of clinical guidelines on hydroxyurea use., (© 2021 Ofakunrin AOD et al.)

Optical folding and rotation behavior of red blood cells (RBCs) in polarized laser tweezers are considerably important for understanding the biophysical and biomechanical properties using the fast probing method. Here, a dual-mode polarized single-laser tweezers technique with distinct principal axes exhibiting different polarization states is presented and designed to investigate the deformation, optical folding, and rotation of single living cells with one measurement. RBC optical folding and rotation speed are measured in patients with sickle cell disease (SCD), including follow up of patients after hydroxyurea (HU) treatment for at least three months. Folding angle and rotation speed are significantly lower in patients with SCD and do not significantly differ in patients treated by HU compared with the healthy control group. The RBC folding angle and rotation speed in patients treated with HU drug increase linearly at lower laser powers and rapidly at higher powers, and increase much slowly in patients not treated with HU. The difference in the folding angle and rotation speed of RBCs could be useful for drug response in SCD or predicting pain crisis in SCD., Competing Interests: Declaration of competing interest ☒ The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021. Published by Elsevier Inc.)

Aging is one of the significant risk factors for Alzheimer's disease (AD). Therefore, this study aimed to propose a new hypothesis "membrane aging" as a critical pathogenesis of AD. The concept of "membrane aging" was reviewed, and the possible mechanisms of membrane aging as the primary culprit of AD were clarified. To further prove this hypothesis, a hydroxyurea-induced "membrane aging" model was established in vitro and in vivo . First, neuronal aging was validated by immunocytochemistry with age-related markers, and membrane aging phenotypes were confirmed. The alterations of membrane fluidity within APP/PS1 mice were re-proved by intracerebroventricular injection of hydroxyurea. Decreased membrane fluidity was found in vitro and in vivo , accompanied by increased total cholesterol concentration in neurons but decreased cholesterol levels within membrane fractions. The Aβ level increased considerably after hydroxyurea treatment both in vitro and in vivo . DHA co-treatment ameliorated membrane aging phenotypes and Aβ aggregation. The study revealed the AMP-activated protein kinase/acetyl CoA carboxylase/carnitine palmitoyl transferase 1 pathway involved in membrane aging processes. These results strongly supported the idea that membrane aging was a pathogenesis of AD and might serve as a new therapeutic target for AD.

Chronic neutrophilic leukemia (CNL) is a rare leukemia with approximately 150 total cases reported. Cutaneous neutrophilic infiltrates, including Sweet syndrome (SS) and leukemia cutis (LC), have been reported in six patients with CNL. In the setting of CNL, these two conditions are difficult to differentiate due to clinical and histopathological similarities, but it is important to do so because LC is associated with a worse prognosis. In general, SS is distinguished by its tenderness, fever, and improvement with steroids (vs chemotherapy for LC). Biopsy of LC reveals immature leukocytes, whereas SS shows almost exclusively mature leukocytes, but morphology alone may not be sufficient in some cases. Here, we report a case of a 72-year-old male with CNL and a cutaneous eruption with clinical and pathological features which made the distinction between the two diseases difficult., (© 2020 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Neurologic complications are common in patients with sickle cell anemia (SCA), but conventional tools such as MRI and transcranial Doppler ultrasonography (TCD) do not fully assess cerebrovascular pathology. Cerebral tissue oximetry measures mixed oxygen saturation in the frontal lobes (S CT O 2 ) and provides early prognostic information about tissue at risk of ischemic injury. Untreated patients with SCA have significantly lower S CT O 2 than healthy controls that declines with age. Hydroxyurea is effective in preventing many SCA-related complications, but the degree to which it preserves normal neurophysiology is unclear. We analyzed participants enrolled in the Therapeutic Response Evaluation and Adherence Trial (TREAT, NCT02286154), which enrolled participants initiating hydroxyurea using individualized dosing (new cohort) and those previously taking hydroxyurea (old cohort) and was designed to monitor the long-term benefits of hydroxyurea. Cerebral oximetry was performed at baseline and annually. For the new cohort (median starting age = 12 months, n = 55), mean baseline S CT O 2 was normal before starting hydroxyurea (mean 65%, 95% CI 58-72%) and significantly increased after 2 years (mean 72%, 95% CI 65-79%, p < .001). The S CT O 2 for patients receiving long-term hydroxyurea (median age = 9.6 years) was normal at study entry (mean 66%, 95% CI 58-74%) and remained stable across 2 years. Both cohorts had significantly higher S CT O 2 than published data from predominantly untreated SCA patients. Cerebral oximetry is a non-invasive method to assess cerebrovascular pathology that complements conventional imaging. Our results indicate that hydroxyurea suggests protection against neurophysiologic changes seen in untreated SCA., (© 2021 Wiley Periodicals LLC.)

Early brain injury (EBI) is a major contributor to the high mortality and morbidity after subarachnoid hemorrhage (SAH). Inflammatory responses and neuronal apoptosis are important causes of EBI. Because 5- lipoxygenase (5-LOX) is known to be involved various central nervous system diseases, we investigated the effects of 5-LOX inhibition during EBI after SAH. Zileuton and LY294002 were used to inhibit expression of 5-LOX and Akt, respectively. We found that 5-LOX expression was significantly increased in the cytoplasm of cortical neurons after SAH and was accompanied by upregulated expression of the inflammatory factors LTB4, TNF-α, IL-1β and IL-6; upregulation of the pro-apoptotic factor Bax; downregulation of the anti-apoptotic factor Bcl-2; and an increased apoptosis rate. Gastric Zileuton administration significantly suppressed all of those effects and improved neurological function. Zileuton also upregulated activated (phosphorylated) AKT levels, and these beneficial effects of Zileuton were abolished by intracerebroventricular infusion of the PI3K inhibitor LY294002. Taken together, these findings indicate that 5-LOX mediates pro-inflammatory and pro-apoptotic effects that contribute to EBI after SAH and that those effects are suppressed by activation of PI3K/Akt signaling. This suggests targeting 5-LOX may be an effective approach to treating EBI after SAH.

Background: Hydroxyurea (HU) is an hemoglobin F inducing agent used in the treatment of sickle cell disease (SCD)., Aim: The aim of this study is to determine the perception of HU by people living with SCD., Materials and Methods: A pretested questionnaire was self-administered to known cases of SCD attending pediatrics and adult hematology clinics in three participating centers. Mothers of children <18 years responded on their behalf., Results: There were 101 responders, 49 (48.5%) males and 52 (51.5%) females, of which 24 (23.8%) were children <18 years and 77 (76.2%) were adults. The majority (n = 73, 72.3%) knew their phenotype. Up to 63 (62.4%) had crises in the past 3 months. Only 35 (34.7%) had heard of HU, many through their doctor (n = 16, 45.7%), 8 (22.9%) through online resources, and 7 (20%) from friends. Only 12 (11.9%) had been exposed to HU therapy, of which 5 (41.7%) had discontinued therapy mostly due to side effects (n = 2, 40%). The seven patients (58.3%) on continuous HU therapy for a duration of 6 months to over 5 years, all reported reduced hospital admissions and frequency of crises as benefits of the drug, whereas 4 (57.1%) had stopped requiring blood transfusion since starting therapy. Of those who had never taken HU, 53 (52.5%) believed that HU should be used in treating SCD and majority (n = 32, 60.4%) would want to be commenced on the drug. However, 8 (15.1%) would decline therapy (mostly due to perceived associated side effects; n = 4; 50%). Six (11.3%) were unsure if they would want the drug and 7 (13.2%) would have to discuss the decision first with their family. There were 8 (8.9%) responders who did not think HU will be beneficial in SCD and would decline treatment, while 26 (29.2%) were unsure of both the benefits of the drug or of commencing therapy., Conclusion: The findings from this study suggest that HU is beneficial for patients with SCD; however, the awareness of this medication among SCD patients is still low in our environment. Some SCD patients would decline the use of HU due to perceived side effects. We recommend that more awareness on HU be created and coordinated multi-center studies on the efficacy of HU in the Nigerian population be carried out., Competing Interests: None

Total pancreatectomy with islet autotransplantation is a complex surgical approach for acute recurrent or chronic pancreatitis that frequently triggers extreme thrombocytosis (platelets ≥ 1000 × 10 9 /L). Thrombocytosis can be prothrombotic, so cytoreductive hydroxyurea is often initiated after this surgery; however, optimal dosing strategy and efficacy are unknown. This prospective pilot study characterized the pharmacokinetics of hydroxyurea after this procedure in children. It also compared them with previously published pediatric parameters in sickle cell anemia (SCA), the disease in which pediatric hydroxyurea pharmacokinetics have primarily been studied. Plasma hydroxyurea levels were quantified in 14 participants aged 4-19 years using high-performance liquid chromatography. Blood collections were scheduled 20 minutes, 1 hour, and 4 hours after the first dose, on pharmacokinetic day 1 (PK1), and again 2-3 months later if still on hydroxyurea (PK2). Six participants had PK1 and PK2 data at all 3 postdose timed collections, 5 only had PK1 samples, and 3 only had PK2 samples. Total pancreatectomy with islet autotransplantation participants had reduced and delayed absorption compared with sickle cell anemia participant data from the Hydroxyurea Study of Long-Term Effects, regardless of timing or dosing methodology. Total pancreatectomy with islet autotransplantation participants had different pharmacokinetic profiles at PK1 versus PK2, with lower dose-normalized exposures than previously reported in sickle cell anemia. These results suggest variability exists in hydroxyurea absorption and bioavailability in total pancreatectomy with islet autotransplantation patients, suspected to be primarily because of Roux-en-Y reconstruction, and suggest that more pharmacokinetic data are needed for scenarios when hydroxyurea is prescribed to children without sickle cell anemia., (© 2020, The American College of Clinical Pharmacology.)

The present study assessed the criteria for initiating cytoreduction and response to conventional therapies in 1446 patients with essential thrombocythemia (ET), 267 (17%) of which were CALR-mutated. In low risk patients, time from diagnosis to cytoreduction was shorter in CALR-positive than in the other genotypes (2·8, 3·2, 7·4 and 12·5 years for CALR, MPL, JAK2V617F and TN, respectively, P < 0·0001). A total of 1104 (76%) patients received cytoreductive treatment with hydroxycarbamide (HC) (n = 977), anagrelide (n = 113), or others (n = 14). The estimated cumulative rates of complete haematological response (CR) at 12 months were 40 % and 67% in CALR and JAK2V617F genotypes, respectively. Median time to CR was 192 days for JAK2V617F, 343 for TN, 433 for MPL, and 705 for CALR genotypes (P < 0·0001). Duration of CR was shorter in CALR-mutated ET than in the remaining patients (P = 0·003). In CALR-positive patients, HC and anagrelide had similar efficacy in terms of response rates and duration. CALR-mutated patients developed resistance/intolerance to HC more frequently (5%, 23%, 27% and 15% for JAK2V617F, CALR, MPL and TN, respectively; P < 0·0001). In conclusion, conventional cytoreductive agents are less effective in CALR-mutated ET, highlighting the need for new treatment modalities and redefinition of haematologic targets for patients with this genotype., (© 2020 British Society for Haematology and John Wiley & Sons Ltd.)

Sperm parameters are known to be impaired in men with sickle cell disease (SCD). Although treatment with hydroxyurea (HU) has an impact on sperm quality, sperm preservation is impossible before puberty. This study's primary objective was to analyze and compare sperm parameters in male patients with SCD exposed (or not) to HU before puberty. Twenty-six sperm samples from 15 patients (median age, 17 years; range, 16-23) treated with HU during childhood were compared with 46 samples from 23 HU-naïve patients (20 years; 16-24). The median age at HU initiation was 6 years (1-14 years), the median duration of HU treatment was 4 years (0.5-10), and the mean dose of HU was 22.4 ± 3.7 mg/kg per day. Although we observed substantial quantitative and qualitative semen abnormalities in all patients, there were no significant differences in semen volume, sperm concentration, total sperm count, or spermatozoa motility, morphology, and vitality between the HU-exposed and HU-naïve groups. At the time of the semen analysis, 100% of the patients in the HU-exposed group and 52% of the patients in the HU-naïve group received transfusion therapy. The specific effect of HU on spermatogenesis in very young infants and the putative value of transfusion for reversing the toxicity of HU warrant further investigation., (© 2021 by The American Society of Hematology.)

Sickle cell disease (SCD) comprises a group of genetic disorders characterized by the presence of the hemoglobin (Hb) S in homozygosis or in heterozygosis with some other Hb variant or in interaction with thalassemia. SCD is characterized by a very complex pathophysiology, which determines a wide variability of clinical manifestations, including a chronic state of hypercoagulability responsible for the increased risk of thromboembolic events. ADAMTS13 and von Willebrand factor (VWF) play an important role in arterial and venous thrombosis. Thus, the aim of this study was to understand how the ADAMTS13-VWF axis behaves in sickle cell disease, as well as whether there is an association of these markers with the use of hydroxyurea (HU). This is a cross-sectional study conducted with 40 patients diagnosed with SCD and 40 healthy individuals. The analysis of the ADAMTS13-VWF axis was comparatively performed between groups of patients and controls and, afterwards, between patients with SCD who were users and non-users of HU. ADAMTS13 activity, ADAMTS13 activity/VWF:Ag, and ADAMTS13:Ag/VWF:Ag ratios were significantly lower and VWF:Ag levels significantly higher in SCD patients when compared to the controls. There was no statistically significant difference in ADAMTS13:Ag and VWF collagen binding (VWF:CB) levels between the groups evaluated. Among the categories of HU use, there was no statistically significant difference in any of the evaluated markers. As a conclusion, we could observe that the ADAMTS13-VWF axis is altered in SCD when compared to healthy individuals and that there is no association between these markers and the use of HU.