On the feasibility of malaria hypothesis.

In 1954, Allison proposed that hemoglobin S (HbS) gene causes protection against fatal malaria. This would explain the high HbS gene frequency observed in certain regions hyperendemic for malaria, so-called "malaria hypothesis". This in silico study was conducted to examine the feasibility of the hypothesis under more realistic initial conditions, where a mutant gene with heterozygous advantage against malaria (e.g., HbS) was introduced in a group of Neolithic hunter-gatherers who decided to start agriculture nearby water where malaria killed a proportion of population. The tribe population size, number of children born to each woman in each generation, mortality from malaria and sickle cell disease, the protection factor provided by the gene carriers against malaria, the probability of mating between the members of the parent and offspring populations, population growth, and increased fertility in women heterozygous for HbS, were also considered. For effectively confer protection against malaria within the shortest possible period, the mutation needs to be happened in a small population. For a large population, the process would take around 100 generations (~ 2500 years) or more to provide an effective protection. Even then, the probability that the new gene could survive and propagate to future generations is about 35%. Conventional population genetics equations with differential or difference equations, give totally incorrect estimates of the gene frequency in small populations; discrete mathematics should be used, instead. After introduction of the advantageous mutation, the gene frequency increased until a steady state value. This value is far less than the gene frequency reported in certain tribes of Africa. It seems that the malaria hypothesis, per se, could not explain such a high observed gene frequency, unless HbS is associated with lower mortality from other causes too.

Bone Health Impairment in Patients with Hemoglobinopathies: From Biological Bases to New Possible Therapeutic Strategies.

Hemoglobinopathies are monogenic disorders affecting hemoglobin synthesis. Thalassemia and sickle cell disease (SCD) are considered the two major hemoglobinopathies. Thalassemia is a genetic disorder and one of the major hemoglobinopathies determined by an impairment of globin chain production, which causes an alteration of erythropoiesis, an improvement in hemolysis, and an alteration of iron homoeostasis. In SCD, the mutations are on the ß-globin chain of hemoglobin which results in a substitution of glutamic acid by valine with consequent formation of Hemoglobin S (HbS). Several factors are involved in bone metabolism alteration in patients with hemoglobinopathies, among them hormonal deficiency, bone marrow hyperplasia, iron overload, inflammation, and increased bone turnover. Bone metabolism is the result of balance maintenance between bone deposition and bone resorption, by osteoblasts (OBs) and osteoclasts (OCs). An impairment of this balance is responsible for the onset of bone diseases, such as osteoporosis (OP). Therefore, here we will discuss the alteration of bone metabolism in patients with hemoglobinopathies and the possible therapeutic strategies to contain and/or counteract bone health impairment in these patients, taking into consideration not only the pharmacological treatments already used in the clinical armamentarium, but also the new possible therapeutic strategies.

Using the daily rate of rise in hemoglobin S to manage RBC depletion/exchange treatment in sickle cell disease.

BACKGROUND: Red blood cell exchange is often used prophylactically in patients with sickle cell disease, with the goal to maintain hemoglobin S (HbS) below a target threshold level. We reviewed whether the daily "rate of rise" (RoR) in HbS that occurs between procedures can be used for patient management. For some patients not achieving their HbS goals despite efficient exchanges, the post-procedure hematocrit (Hct) target is increased to potentially suppress HbS production. This case series explores the utility of this approach, other clinical uses of the daily RoR in HbS, and the factors that influence it. STUDY DESIGN AND METHODS: A total of 660 procedures from 24 patients undergoing prophylactic RBC depletion/exchange procedures were included. Laboratory values and clinical parameters were collected and used to calculate the daily RoR in HbS. Factors such as Hct or medications that might influence the RoR in HbS were evaluated. RESULTS: The RoR in HbS varied widely between patients but remained relatively stable within individuals. Surprisingly, this value was not significantly influenced by changes in post-procedure Hct or concurrent hydroxyurea use. A patient's average RoR in HbS effectively predicted the pre-procedure HbS at the following visit (R2 = 0.65). DISCUSSION: The RoR in HbS is a relatively consistent parameter for individual patients that is unaffected by medication use or procedural Hct targets and may be useful in determining intervals between procedures.

The impact of grip strength, waist circumference, and body mass index on Hemoglobin A1c value: Cross-sectional study using outpatient clinical data in Japanese elderly patients with type 2 diabetes mellitus.

AIM: Grip strength (GS) as a surrogate for muscular strength, waist circumference (WC) as a surrogate marker of visceral fat, and body mass index (BMI) as a surrogate marker of obesity should also be considered markers for the management of risks associated with type 2 diabetes mellitus (T2DM). However, in terms of the management of T2DM in elderly patients, the accentuated heterogeneity of sarcopenic change might modify the associations between those factors and glycemic control. In this cross-sectional study, we aimed to clarify the impact of GS, WC, and BMI on hemoglobin A1c (HbA1c) in elderly Japanese patients with T2DM. METHODS: GS, WC, and BMI were measured in 327 patients. Odds ratios (ORs) and 95% confidence intervals (CIs) for good glycemic control (HbA1c < 7.0%) were investigated to analyze the three variables as numerical values by dividing them into tertiles. All results were expressed after adjustment was made for the confounders of age, sex, and number of diabetes medications being used by the study participants. RESULTS: The ORs of GS, WC, and BMI for well-controlled HbA1c were 1.056 (95% CI, 1.016-1.098), 0.986 (95% CI, 0.960-1.013), and 1.032 (95% CI, 0.959-1.111), respectively. The OR of 3.726 (95% CI, 1.831-7.581) in the high tertile for GS was significantly higher than the OR in the low tertile, and no differences were observed among the tertiles for WC and BMI. CONCLUSIONS: Based on that result, GS was found to have more potential as an effective marker of glycemic control than WC or BMI among elderly Japanese patients with T2DM. Geriatr Gerontol Int 2024; 24: 410-414.

MALDI-MS in first-line screening of newborns for sickle cell disease: results from a prospective study in comparison to HPLC.

OBJECTIVES: Newborn screening (NBS) for sickle cell disease (SCD) requires a robust, high-throughput method to detect hemoglobin S (HbS). Screening for SCD is performed by qualitative methods, such as isoelectric focusing (IEF), and both qualitative and quantitative methods such as high performance liquid chromatography (HPLC), capillary electrophoresis (CE), and tandem mass spectrometry (MS/MS). All these methods detect HbS, as well as low-level or absent HbA, and also other variants of hemoglobin. HPLC is considered as a reference method for NBS, because of its high sensitivity and specificity in detecting HbS. NeoSickle®, a fully automated matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) platform, combined with automated sample processing, a laboratory information management system and NeoSickle® software for automatic data interpretation, has increased the throughput of SCD testing. The purpose of this study was to compare the performances of NeoSickle® and HPLC. METHODS: A prospective study was conducted including 9,571 samples from the NBS program to compare MALDI-MS using NeoSickle® with an HPLC method. Correlation between the two methods was studied. For the MALDI-MS method, sensitivity, specificity, NPV, and PPV were calculated. RESULTS: We found over 99.4 % correlation between the HPLC and MALDI-MS results. NeoSickle® showed 100 % of sensitivity and specificity in detecting SCD syndrome, leading to positive and negative predictive values of 100 %. CONCLUSIONS: NeoSickle® is adapted to NBS for SCD, and can be used in first-line high-throughput screening to detect HbS, and beta-thalassemia major warning. When HbS is detected, second-line use of another specific method as HPLC is necessary.

Splice Acceptor Mutation [HBB:c.93-2A > T] in a Patient with Hb S/ß0-Thalassemia.

We report a case of Hb S/ß0-thalassemia (Hb S/ß0-thal) in a patient who is a compound heterozygote for the Hb Sickle mutation (HBB:c.20A > T) and a mutation of the canonical splice acceptor sequence of IVS1 (AG > TG, HBB:c.93-2A > T). This is the fifth mutation involving the AG splice acceptor site of IVS1, all of which prevent normal splicing and cause ß0-thal.

Evaluating sheep hemoglobins with MD simulations as an animal model for sickle cell disease.

Sickle cell disease (SCD) affects millions worldwide, yet there are few therapeutic options. To develop effective treatments, preclinical models that recapitulate human physiology and SCD pathophysiology are needed. SCD arises from a single Glu-to-Val substitution at position 6 in the ß subunit of hemoglobin (Hb), promoting Hb polymerization and subsequent disease. Sheep share important physiological and developmental characteristics with humans, including the same developmental pattern of fetal to adult Hb switching. Herein, we investigated whether introducing the SCD mutation into the sheep ß-globin locus would recapitulate SCD's complex pathophysiology by generating high quality SWISS-MODEL sheep Hb structures and performing MD simulations of normal/sickle human (huHbA/huHbS) and sheep (shHbB/shHbS) Hb, establishing how accurately shHbS mimics huHbS behavior. shHbS, like huHbS, remained stable with low RMSD, while huHbA and shHbB had higher and fluctuating RMSD. shHbB and shHbS also behaved identically to huHbA and huHbS with respect to ß2-Glu6 and ß1-Asp73 (ß1-Asn72 in sheep) solvent interactions. These data demonstrate that introducing the single SCD-causing Glu-to-Val substitution into sheep ß-globin causes alterations consistent with the Hb polymerization that drives RBC sickling, supporting the development of a SCD sheep model to pave the way for alternative cures for this debilitating, globally impactful disease.

Biophysical chemistry behind sickle cell anemia and the mechanism of voxelotor action.

Sickle cell anemia disease has been a great challenge to the world in the present situation. It occurs only due to the polymerization of sickle hemoglobin (HbS) having Pro-Val-Glu typed mutation, while the polymerization does not occur in normal hemoglobin (HbA) having Pro-Glu-Glu peptides. It is also well confirmed that the oxygenated HbS (OHbS) does not participate in the polymerization, while the deoxygenated HbS (dHbS) does, which causes the shape of red blood cells sickled. After polymerization, the blood has a low oxygen affinity. Keeping this fact into consideration, only those drugs are being synthesized that stabilize the OHbS structure so that the polymerization of HbS can be stopped. The literature data showed no systematic description of the changes occurring during the OHbS conversion to dHbS before polymerization. Hence, an innovative reasonable study between HbA and HbS, when they convert into their deoxygenated forms, was done computationally. In this evaluation, physiochemical parameters in HbA/HbS before and after deoxygenation were studied and compared deeply. The computationally collected data was used to understand the abnormal behaviour of dHbS arising due to the replacement of Glu6 with Val6. Consequently, during the presented computational study, the changes occurring in HbS were found opposite/abnormal as compared to HbA after the deoxygenation of both. The mechanism of Voxelotor (GBT-440) action to stop the HbS polymerization was also explained with the help of computationally collected data. Besides, a comparative study between GBT-440 and another suggested drug was also done to know their antisickling strength. Additionally, the effect of pH, CO, CO2, and 2,3-diphosphoglycerate (2,3-DPG) on HbS structure was also studied computationally.

In vitro delayed response to dihydroartemisinin of malaria parasites infecting sickle cell erythocytes.

BACKGROUND: Decreased efficacy of artemisinin-based combination therapy (ACT) for Plasmodium falciparum malaria has been previously reported in patients with sickle cell disease (SCD). The main purpose of this study was to investigate the in vitro susceptibility of isolates to dihydro-artemisinin (DHA) to provide a hypothesis to explain this treatment failure. METHODS: Isolates were collected from patients attending health centres in Abidjan with uncomplicated P. falciparum malaria. The haemoglobin type has been identified and in vitro drug sensitivity tests were conducted with the ring stage assay and maturation inhibition assay. RESULTS: 134 isolates were obtained. Parasitaemia and haemoglobin levels at inclusion were lower in patients with haemoglobin HbSS and HbSC than in patients with normal HbAA. After ex vivo RSA and drug inhibition assays, the lowest rate of parasitic growth was found with isolates from HbAS red cells. Conversely, a significantly higher survival rate of parasites ranging from 15 to 34% were observed in isolates from HbSS. Isolates with in vitro reduced DHA sensitivity correlate with lower RBC count and haematocrit and higher parasitaemia at inclusion compared to those with isolates with normal DHA sensitivity. However, this decrease of in vitro sensitivity to DHA was not associated with Kelch 13-Propeller gene polymorphism. CONCLUSION: This study highlights an in vitro decreased sensitivity to DHA, for isolates collected from HbSS patients, not related to the Pfkelch13 gene mutations. These results are in line with recent studies pointing out the role of the redox context in the efficacy of the drug. Indeed, SCD red cells harbour a highly different ionic and redox context in comparison with normal red cells. This study offers new insights into the understanding of artemisinin selective pressure on the malaria parasite in the context of haemoglobinopathies in Africa.

Quantitative Model-Based Assessment of Multiple Sickle Cell Disease Therapeutic Approaches Alone and in Combination.

Three sickle cell disease (SCD) treatment strategies, stabilizing oxygenated hemoglobin (oxyHb), lowering 2,3-BPG, and inducing fetal hemoglobin (HbF) expression aim to prevent red blood cell (RBC) sickling by reducing tense-state sickle hemoglobin that contributes to polymer formation. Induction of 30% HbF is seen as the gold standard because 30% endogenous expression is associated with a lack of symptoms. However, the level of intervention required to achieve equivalent polymerization protection by the other strategies is uncertain, and there is little understanding of how these approaches could work in combination. We sought to develop an oxygen saturation model that could assess polymerization protection of all three approaches alone or in combination by extending the Monod-Wymann-Changeux model to include additional mechanisms. Applying the model to monotherapies suggests 51% sickle hemoglobin (HbS) occupancy with an oxyHb stabilizer or lowering RBC 2,3 BPG concentrations to 1.8 mM would produce comparable polymerization protection as 30% HbF. The model predictions are consistent with observed clinical response to the oxyHb stabilizer voxelotor and the 2,3-BPG reducer etavopivat. The model also suggests combination therapy will have added benefit in the case of dose limitations, as is the case for voxelotor, which the model predicts could be combined with 20% HbF or 2,3-BPG reduction to 3.75 mM to reach equivalent protection as 30% HbF. The proposed model represents a unified framework that is useful in supporting decisions in preclinical and early clinical development and capable of evolving with clinical experience to gain new and increasingly confident insights into treatment strategies for SCD.

A low-cost miniature immunosensor for haemoglobin as a device for the future detection of gastrointestinal bleeding.

Gastrointestinal bleeding (GIB) is a serious medical condition, which requires immediate attention to establish the cause of the bleeding. Here, we present the development of a miniaturised electrochemical impedance spectroscopy (EIS) device for the detection of GIB. The device performs EIS measurements up to 100 kHz. Following the development of an immunosensor for haemoglobin (Hb) on screen printed electrodes, the EIS device was used for detecting Hb as an early indication of bleeding. The sensor was able to detect Hb in a redox solution in a linear range between 5 µg mL-1 and 60 µg mL-1, with a limit of detection of 13.3 µg mL-1. It was also possible to detect Hb in simulated intestinal fluid, without the need for a redox solution, within a range of 10 µg mL-1 to 10 mg mL-1 with a limit of detection of 2.31 mg mL-1. The miniature EIS device developed in this work is inexpensive, with an estimated cost per unit of £30, and has shown a comparable performance to existing commercial tools, demonstrating its potential to be used in the future as an ingestible sensor to detect GIB. All these measurements were carried out in a purpose built flow cell with supporting hardware electronics outside the cell. Integration of the hardware and the sensing electrodes was demonstrated in pill form. This pill after integration sampling fluidics has potential to be used in detecting gastrointestinal bleeding.

Self-Reported Food Security in Adolescents with Type 1 Diabetes: Association with Hemoglobin A1c and Mental Health Symptoms Independent of Household Food Security.

BACKGROUND: Typically, child exposure to food insecurity is assessed by caregiver reports of household food security. Child report has the potential for greater accuracy because it pertains only to the child whose experiences may differ from caregiver reports. OBJECTIVE: We assessed if adolescent-reported food insecurity was associated with levels of hemoglobin A1c (HbA1c), acute diabetes-related complications, depressive symptoms, and disordered eating behaviors in adolescents with type 1 diabetes, independently from household food security. METHODS: In a cross-sectional analysis of the multicenter SEARCH for Diabetes in Youth Cohort Study (phase 4, 2016-2019) including 601 adolescents aged 10-17 y with type 1 diabetes and their caregivers, household food security, and adolescent-reported food security were assessed using the 18-item Household Food Security Survey Module and the 6-item Child Food Security Assessment questionnaire. Age-stratified (10-13 and 14-17) regression models were performed to estimate independent associations, adjusting for sociodemographics, clinical factors, and household food security. RESULTS: Food insecurity was reported by 13.1% (n = 79) of adolescents and 15.6% (n = 94) of caregivers. Among adolescent-caregiver dyads, 82.5% (n = 496) of reports were concordant and 17.5% (n = 105) discordant, Cohen's κ= 0.3. Adolescent-reported food insecurity was not independently associated with HbA1c, diabetic ketoacidosis, and severe hypoglycemia, including in age-stratified analyses. Adolescent-reported food insecurity was independently associated with elevated odds of depressive symptoms [odds ratio (OR): 3.6; 95% confidence interval (CI): 1.3, 10.3] and disordered eating behaviors (OR: 2.5, 95% CI: 1.4, 4.6) compared with adolescents reporting food security; these associations remained in both age groups for disordered eating behaviors and in the older group for depressive symptoms. CONCLUSIONS: Adolescents with type 1 diabetes may experience food insecurity differently than caregivers. Adolescent-reported food insecurity was independently associated with depressive symptoms and disordered eating behaviors and thus may be an important attribute to assess in addition to household food security in adolescents with type 1 diabetes.

Reliability of hemoglobin A2 value as measured by the Premier Resolution system for screening of ß-thalassemia carriers.

OBJECTIVES: Accurate quantification of hemoglobin (Hb) A2 is vital for diagnosing ß-thalassemia carriers. This study aimed to assess the precision and diagnostic utility of HbA2 measurements using the new high-performance liquid chromatography (HPLC) method, Premier Resolution, in comparison to capillary electrophoresis (CE). METHODS: We analyzed 418 samples, previously identified as A2A by CE, using Premier Resolution-HPLC. We compared the results, established correlations, and determined an optimal HbA2 cutoff value for ß-thalassemia screening. Additionally, we prospectively evaluated the chosen cutoff value in 632 samples. Mutations in the ß- and α-globin genes were identified using polymerase chain reaction (PCR) techniques and DNA sequencing. RESULTS: HbA2 levels were consistently higher with Premier Resolution, yet there was a significant correlation with CE in all samples (bias, -0.33; r, 0.991), ß-thalassemia (bias, -0.27; r, 0.927), and non-ß-thalassemia carriers (bias, -0.36; r, 0.928). An HbA2 cutoff value of ≥4.0 % for ß-thalassemia screening achieved 100 % sensitivity and 99.6 % specificity. Further validation yielded sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of 97.3 , 99.8, 97.3, 99.8, and 99.7 %, respectively. We also identified a rare ß-Hb variant, Hb La Desirade [HBB:c.389C>T], associated with ß-thalassemia and co-inherited with a single α-globin gene. CONCLUSIONS: The Premier Resolution HPLC is a reliable and accurate method for routine ß-thalassemia carrier screening, aligning with existing CE methods.

Natural history of blood pressure in sickle cell disease pregnancy.

In this retrospective cohort study of singleton pregnancies in people with sickle cell disease (SCD) delivered at two academic centres between 1990 and 2021, we collected demographic and SCD-related data, pregnancy outcomes, and the highest systolic and diastolic blood pressure (SBP and DBP) at seven time periods. We compared blood pressure values and trajectories in the composite cohort and in each genotype group to control values in a non-SCD pregnancy dataset. There were 290 pregnancies among 197 patients with SCD. Sixteen per cent (n = 47) of pregnancies had a hypertensive disorder of pregnancy (HDP); the rates did not differ by genotype. The mean SBP and DBP were lower in the HbSS/HbSß0 group than in the non-SCD control group at all timepoints. Mean SBP and DBP trajectories were similar between the HbSS/HbSß0 group and non-SCD controls, whereas the mean SBP and DBP in the HbSC/HbSß+ group decreased between the first and second trimesters and plateaued between the second and third trimesters. There were no differences in blood pressure trajectory by haemoglobin >/< 10 gm/dL or by chronic transfusion status. Overall, pregnant people with SCD have lower blood pressure than unaffected pregnant people, raising the possibility that HDP are underdiagnosed, particularly in people with HbSS/HbSß0 .

Profiling the Plasmodium falciparum Erythrocyte Membrane Protein 1-Specific Immununoglobulin G Response Among Ghanaian Children With Hemoglobin S and C.

Members of the Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) family are important targets for protective immunity. Abnormal display of PfEMP1 on the surfaces of infected erythrocytes (IEs) and reduced cytoadhesion have been demonstrated in hemoglobin (Hb) AS and HbAC, inherited blood disorders associated with protection against severe P. falciparum malaria. We found that Ghanaian children with HbAS had lower levels of immunoglobulin G against several PfEMP1 variants and that this reactivity increased more slowly with age than in their HbAA counterparts. Moreover, children with HbAS have lower total parasite biomass than those with HbAA at comparable peripheral parasitemias, suggesting impaired cytoadhesion of HbAS IEs in vivo and likely explaining the slower acquisition of PfEMP1-specific immunoglobulin G in this group. In contrast, the function of acquired antibodies was comparable among Hb groups and appears to be intact and sufficient to control parasitemia via opsonization and phagocytosis of IEs.

Potential for a large-scale newborn screening strategy for sickle cell disease in Mali: A comparative diagnostic performance study of two rapid diagnostic tests (SickleScan® and HemotypeSC®) on cord blood.

Sickle cell disease (SCD) is a life-threatening disease requiring reliable early diagnosis. We assessed the acceptability and diagnostic performances of two rapid diagnostic tests (RDTs) to identify SCD (HbSS, HbSC, HbS/ß-thalassaemia) or SCD carrier (HbS/HbC) in a pilot SCD newborn screening (NBS) strategy in Mali. All consenting delivering women were offered SCD NBS using cord blood sampling on two RDTs (SickleScan® and HemotypeSC®) compared to the high-performance liquid chromatography (HPLC) gold standard to detect SCD states. From April 2021 to August 2021, 4333 delivering women were eligible of whom 96.1% were offered NBS: 1.6% refused, 13.8% delivered before consenting and 84.6% consented; 3648 newborns were diagnosed by HPLC; 1.64% had SCD (0.63% HbSS, 0.85% HbSC, 0.16 HbS/ß-plus-thalassaemia); 21.79% were SCD carrier. To detect accurately SCD, SickleScan® had a sensitivity of 81.67% (95% confidence interval [CI]: 71.88-91.46) and a negative predictive value (NPV) of 99.69% (95% CI: 99.51-99.87); HemotypeSC® had a sensitivity of 78.33% (95% CI: 67.91-88.76) and a NPV of 99.64% (95% CI: 99.44-99.83). To detect SCD carrier: SickleScan® sensitivity was 96.10% (95% CI: 94.75-97.45) and NPV, 98.90% (95% CI: 98.51-99.29); HemotypeSC® sensitivity was 95.22% (95% CI: 93.74-96.70) and NPV, 98.66% (95% CI: 98.24-99.03). Routine SCD NBS was acceptable. Compared with HPLC, both RDTs had reliable diagnostic performances to exclude SCD-free newborns and to identify SCD carriers to be further confirmed. This strategy could be implemented in large-scale NBS programmes.

Acute chest syndrome in children with sickle cell disease: Data from a national AIEOP cohort identify priority areas of intervention in a hub-and-spoke system.

Acute chest syndrome (ACS) is a frequent cause of hospitalization in sickle cell disease (SCD). Despite advances in acute care, many settings still lack knowledge about ACS best practices. After the AIEOP Guidelines were published in 2012, suggesting standardized management in Italy, a retrospective study was performed to assess the diagnostic and therapeutic pathways of ACS in children. From 2013 to 2018, 208 ACS episodes were presented by 122/583 kids in 11 centres. 73 were male, mean age 10.9 years, 85% African, 92% HbSS or Sß°. In our hub-and-spoke system, a good adherence to Guidelines was documented, but discrepancies between reference centres and general hospitals were noted. Improvement is needed for timely transfer to reference centres, use of incentive spirometry, oxygen therapy and pain management.

Rapid haemoglobin A and S quantification using Tosoh HLC-723G8 in variant mode for patients with sickle cell disease.

The management of life-threatening complications in patients with sickle cell disease (SCD) requires an accurate and reproducible quantification of haemoglobin A (HbA) and S (HbS) with a short turnaround time and 24-7 availability. We propose a novel method for quantifying HbA and HbS using the glycated haemoglobin (HbA1c) assay on a Tosoh HLC-723G8 (G8) analyser in variant mode. HbA and HbS results obtained using our method highly correlated with results obtained using a reference method (r > 0.99 for 124 samples of patients with SCD or sickle cell trait). Our method met laboratory requirements for linearity (coefficient of variation [CV] and bias <5%), between-run and within-run reproducibility (CV <10%) and carryover (<0.5%) over the range of HbS and HbA values expected in a therapeutic context. Using the G8 analyser in variant mode is viable for monitoring HbA and HbS concentrations in dire situations. This method is easy to use, quick (1.6 min per sample), and automatable and produces highly reproducible results without significant bias. Finally, it does not require modifications to the analytical pipeline recommended by the supplier, enabling a 24-7 availability without disrupting routine monitoring of HbA1c in the laboratory.

Madrid Newborn Sickle Cell Disease Cohort: clinical outcomes, stroke prevention and survival.

In May 2003, Madrid established the universal newborn screening (NBS) for sickle cell disease (SCD). However, there are no studies resembling the evolution of a SCD neonate cohort followed according to national guidelines in Spain. The aim of this study is to describe the morbimortality and the stroke prevention programme in patients diagnosed by SCD NBS in Madrid. This is a multicentre, observational, prospective cohort study between 2003 and 2018; 187 patients diagnosed with SCD were included (151 HbSS, 6 HbSß0, 27 HbSC, 3 HbSß +), and median follow-up was 5.2 years (0.03-14.9). There were 5 deaths: 2 related to SCD in patients with severe genotype (HbSS/HbSß0). Overall survival reached 95% and SCD-related survival 96.8%. The most frequent events were fever without focus, vaso-occlusive crises and acute chest syndromes. Eight strokes occurred in 5 patients which led to a 90.7% stroke-free survival in severe genotype patients (first stroke rate, 0.54 per 100 patient-years). Transcranial Doppler (TCD) was performed in 95% of eligible patients; 75% of children with pathological TCD remained stroke-free. Regarding HbSS/HbSß0 patients, 50.1% received hydroxyurea and 9.5% haematopoietic stem cell transplantation. This study reflects the evolution of Madrid SCD cohort and provides morbimortality data similar to other developed countries.

Targeted modification of furan-2-carboxaldehydes into Michael acceptor analogs yielded long-acting hemoglobin modulators with dual antisickling activities.

Sickle cell disease (SCD) is the most common genetic disorder, affecting millions of people worldwide. Aromatic aldehydes, which increase the oxygen affinity of human hemoglobin to prevent polymerization of sickle hemoglobin and inhibit red blood cell (RBC) sickling, have been the subject of keen interest for the development of effective treatment against SCD. However, the aldehyde functional group metabolic instability has severly hampered their development, except for voxelotor, which was approved in 2019 for SCD treatment. To improve the metabolic stability of aromatic aldehydes, we designed and synthesized novel molecules by incorporating Michael acceptor reactive centers into the previously clinically studied aromatic aldehyde, 5-hydroxymethylfurfural (5-HMF). Eight such derivatives, referred to as MMA compounds were synthesized and studied for their functional and biological activities. Unlike 5-HMF, which forms Schiff-base interaction with αVal1 nitrogen of hemoglobin, the MMA compounds covalently interacted with ßCys93, as evidenced by reverse-phase HPLC and disulfide exchange reaction, explaining their RBC sickling inhibitory activities, which at 2 mM and 5 mM, range from 0% to 21% and 9% to 64%, respectively. Additionally, the MMA compounds showed a second mechanism of sickling inhibition (12%-41% and 13%-62% at 2 mM and 5 mM, respectively) by directly destabilizing the sickle hemoglobin polymer. In vitro studies demonstrated sustained pharmacologic activities of the compounds compared to 5-HMF. These findings hold promise for advancing SCD therapeutics.