Overview of the Association Between the Pathophysiology, Types, and Management of Sickle Cell Disease and Stroke.

Sickle cell disease (SCD) is a genetic blood disorder that affects hemoglobin and increases stroke risk, particularly in childhood. This review examines the pathophysiological association between SCD and stroke, the classification of stroke types, risk factors, diagnosis, management, prevention, and prognosis. A comprehensive literature search was conducted via PubMed, Scopus, and Cochrane databases. Relevant studies on SCD and stroke pathophysiology, classification, epidemiology, diagnosis, treatment, and prevention were identified. Sickle cell disease causes red blood cells to become rigid and sickle-shaped, obstructing blood vessels. Recurrent sickling alters cerebral blood flow and damages vessel walls, often leading to ischemic or hemorrhagic strokes (HS). These occur most frequently in childhood, with ischemic strokes (IS) being more common. Key risk factors include a prior transient ischemic attack (TIA), low hemoglobin, and a high leukocyte count. Neuroimaging is essential for diagnosis and determining stroke type. Primary prevention centers on blood transfusions and hydroxyurea for those at high risk. Acute treatment involves promptly restoring blood flow and managing complications. However, significant knowledge gaps remain regarding stroke mechanisms, optimizing screening protocols, and improving long-term outcomes. This review synthesizes current evidence on SCD and stroke to highlight opportunities for further research and standardizing care protocols across institutions. Ultimately, a holistic perspective is critical for mitigating the high risk of debilitating strokes in this vulnerable patient population.

Acute macular infarctions in pediatric patients with hemoglobin SS disease.

Purpose: To report two cases of symptomatic posterior pole arterial occlusions in patients with hemoglobin SS disease. Observations: Two teenage patients with hemoglobin SS disease presented with visual distortions, and on dilated fundus examination and testing, they were found to have arterial occlusions involving the posterior pole. The patients were evaluated for stroke with head imaging and received exchange transfusion by hematology. Conclusions and Importance: This case series reports the unusual findings of arterial occlusions in the posterior pole resulting in areas of retinal whitening and ischemia in patients with HbSS. While sickle cell retinopathy is typically considered a peripheral retinal disease, these findings underscore the importance of vigilance when examining patients with sickle cell disease.

A Patient Presents for Dental Extraction and Goes into Sickle Cell Crisis in the Dental Chair.

Sickle Cell Disease is an inherited autosomal recessive hemoglobinopathy associated with multiorgan damage. This single gene disorder involves one DNA base pair alteration, producing HbS. The sickle-shaped cells form when deoxygenated in the capillaries. The resulting RBC stasis leads to ischemia and pain, and acute and chronic organ damage. Patients with SCD presenting to a dental office need careful examination to rule out any current infections, neurologic deficits, or other organ involvement before formulating a dental treatment plan to avoid prolonged and complicated procedures. Early intervention and dental anxiety management are key to the dental treatment of patients with SCD.

Quantitation of hemoglobins using Sebia Capillarys-2 capillary electrophoresis (CE) for A1c: Comparison to results using CE for hemoglobins.

Background: Measurement of A1c using the Sebia Capillarys-2 capillary electrophoresis (A1c CE) involves relative quantitative measurements of peaks for hemoglobins A1c, A, A2. We examined correlation of A1c CE results with results of CE analysis for hemoglobins (Hb CE) for homozygous A and S-trait patients. We specifically examined whether abnormalities in A2 or the A/S ratio by A1c CE alone would reasonably be the basis for recommendation of red cell indices for evaluation of possible thalassemia. Methods: Selection of patients was from results for A1c CE, exhibiting either a normal pattern or a pattern consistent with S-trait. We then examined correlation of results of quantitation for A, S and A2 between A1c CE and Hb CE. Results: %A2 by A1c CE (y) had high correlation with %A2 by Hb CE (x): y = 0.88 x; r = 0.948. %A2 in S-trait patients was right-shifted in comparison to normals by 0.5%. For S-trait patients, the A/S ratio by A1c CE (y) had high correlation with the A/S ratio by Hb CE (x): y = 1.02 x; r = 0.995. Conclusions: Given high correlation of results between A1c CE and Hb CE, patent elevation of A2 by A1c CE for either normal or S-trait patients is a reasonable basis for recommendation of red cell indices for evaluation of possible beta thalassemia. For S-trait patients, patent abnormality in the A/S ratio by A1c CE is a reasonable basis for recommendation of red cell indices for evaluation of possible alpha or beta thalassemia.

Evolutionary honing in and mutational replacement: how long-term directed mutational responses to specific environmental pressures are possible.

Recent results have shown that the human malaria-resistant hemoglobin S mutation originates de novo more frequently in the gene and in the population where it is of adaptive significance, namely, in the hemoglobin subunit beta gene compared to the nonresistant but otherwise identical 20A[Formula: see text]T mutation in the hemoglobin subunit delta gene, and in sub-Saharan Africans, who have been subject to intense malarial pressure for many generations, compared to northern Europeans, who have not. This finding raises a fundamental challenge to the traditional notion of accidental mutation. Here, we address this finding with the replacement hypothesis, according to which preexisting genetic interactions can lead directly and mechanistically to mutations that simplify and replace them. Thus, an evolutionary process under selection can gradually hone in on interactions of importance for the currently evolving adaptations, from which large-effect mutations follow that are relevant to these adaptations. We exemplify this hypothesis using multiple types of mutation, including gene fusion mutations, gene duplication mutations, A[Formula: see text]G mutations in RNA-edited sites and transcription-associated mutations, and place it in the broader context of a system-level view of mutation origination called interaction-based evolution. Potential consequences include that similarity of mutation pressures may contribute to parallel evolution in genetically related species, that the evolution of genome organization may be driven by mutational mechanisms, that transposable element movements may also be explained by replacement, and that long-term directed mutational responses to specific environmental pressures are possible. Such mutational phenomena need to be further tested by future studies in natural and artificial settings.

Sickle cell anemia: hierarchical cluster analysis and clinical profile in a cohort in Brazil

Abstract Introduction Sickle cell anemia is a monogenic disorder caused by a mutation in the β-hemoglobin gene, resulting in sickle hemoglobin that can polymerize. Presentation and clinical course have significant inter-individual variability and classifying these patients for severity is a challenge. Methods We applied hierarchical clusters with 10 routine laboratory tests to understand if this grouping could be associated with clinical manifestations. We included 145 adult homozygous patients (SS) at an outpatient clinic in a retrospective study. Results We found five clusters by counting those that had been differentiated by unconjugated bilirubin, reticulocytes, LDH, leukocytes, lymphocytes and monocytes. When comparing groups to clinical findings, the clusters were different only for liver abnormality. Cluster 3 had the lower median of reticulocytes, LDH, leukocytes, lymphocytes and monocytes and a higher percentage of patients under treatment. Clusters 4 and 5 had higher frequencies of liver impairment and higher medians of reticulocytes, LDH, leukocytes, lymphocytes and monocytes. Hemolysis and inflammation seemed to influence the grouping. Conclusion In our study, cluster analysis showed five groups that exhibited different degrees of inflammation and hemolysis. When comparing clinical data, the result was different only for the criteria of liver abnormality.

Sickle cell anemia: hierarchical cluster analysis and clinical profile in a cohort in Brazil.

INTRODUCTION: Sickle cell anemia is a monogenic disorder caused by a mutation in the ß-hemoglobin gene, resulting in sickle hemoglobin that can polymerize. Presentation and clinical course have significant inter-individual variability and classifying these patients for severity is a challenge. METHODS: We applied hierarchical clusters with 10 routine laboratory tests to understand if this grouping could be associated with clinical manifestations. We included 145 adult homozygous patients (SS) at an outpatient clinic in a retrospective study. RESULTS: We found five clusters by counting those that had been differentiated by unconjugated bilirubin, reticulocytes, LDH, leukocytes, lymphocytes and monocytes. When comparing groups to clinical findings, the clusters were different only for liver abnormality. Cluster 3 had the lower median of reticulocytes, LDH, leukocytes, lymphocytes and monocytes and a higher percentage of patients under treatment. Clusters 4 and 5 had higher frequencies of liver impairment and higher medians of reticulocytes, LDH, leukocytes, lymphocytes and monocytes. Hemolysis and inflammation seemed to influence the grouping. CONCLUSION: In our study, cluster analysis showed five groups that exhibited different degrees of inflammation and hemolysis. When comparing clinical data, the result was different only for the criteria of liver abnormality.

Natural History of Malaria Infections During Early Childhood in Twins.

BACKGROUND: The frequency and clinical presentation of malaria infections show marked heterogeneity in epidemiological studies. However, deeper understanding of this variability is hampered by the difficulty in quantifying all relevant factors. Here, we report the history of malaria infections in twins, who are exposed to the same in utero milieu, share genetic factors, and are similarly exposed to vectors. METHODS: Data were obtained from a Malian longitudinal birth cohort. Samples from 25 twin pairs were examined for malaria infection and antibody responses. Bayesian models were developed for the number of infections during follow-up. RESULTS: In 16 of 25 pairs, both children were infected and often developed symptoms. In 8 of 25 pairs, only 1 twin was infected, but usually only once or twice. Statistical models suggest that this pattern is not inconsistent with twin siblings having the same underlying infection rate. In a pair with discordant hemoglobin genotype, parasite densities were consistently lower in the child with hemoglobin AS, but antibody levels were similar. CONCLUSIONS: By using a novel design, we describe residual variation in malaria phenotypes in naturally matched children and confirm the important role of environmental factors, as suggested by the between-twin pair heterogeneity in malaria history.

Reconsidering sickle cell trait testing of red blood cell units allocated to children with sickle cell disease.

BACKGROUND: Sickle cell trait (SCT) testing of red blood cell (RBC) units is sometimes performed to identify and divert units containing hemoglobin S (HbS). Recipients strategically guarded against this exposure include fetuses, neonates, and children with sickle cell disease (SCD). The clinical necessity of this practice is unclear. STUDY DESIGN AND METHODS: A one-year audit (2018) was performed at a pediatric tertiary care hospital that tests for SCT in RBC units prescribed to children with SCD and neonates. The impact of incorporating varying numbers of SCT RBC units in a single-unit top-up, partial-manual red cell exchange, and automated erythrocytapheresis was modeled in four typical-parameter age scenarios (2, 5, 10, and 18 years) sharing a high baseline HbS. Additionally, a survey assessing SCT testing practices was administered to Canadian pediatric hospital transfusion laboratories serving hemoglobinopathy programs. RESULTS: Of 2268 donor RBC units tested, one was positive for SCT (0.04% [95% CI: 0.01%-0.24%]), at a cost of $19,384.56 CAD. The impact of SCT unit incorporation on lost HbS reduction was modest (Δ1%-3% [automated erythrocytapheresis] and Δ4%-15% [top-up/partial manual exchange]). The survey (with all 13 sites responding) showed variable SCT testing practice; four (31%) do not test, four (31%) test for children with SCD, and six (46%) test for neonates. CONCLUSION: RBC SCT testing may be more costly than beneficial or necessary in children with SCD. As of 2019, our transfusion service has ceased SCT testing for this population. Further research in the fetal/neonatal populations is needed to overturn this entrenched practice.

Hypercoagulability in Sickle Cell Disease: A Thrombo-Inflammatory Mechanism.

Sickle cell disease (SCD) is a group of inherited disorders characterized by the presence of abnormal hemoglobin S. Patients with SCD suffer from frequent episodes of anemia, chronic hemolysis, pain crisis, and vaso-occlusion. Additionally, SCD is associated with diverse and serious clinical complications, including thrombosis, which can lead to organ failure, increased morbidity, and eventually, mortality. SCD is known to be a hypercoagulable condition, and the cause of hypercoagulability is multifactorial, with the molecular basis of hemoglobin S being the main driver. The presence of hemoglobin S induces sickling of the RBCs and their subsequent hemolysis, as well as oxidative stress. Both of these processes can alter the hemostatic system, through the activation of platelets, coagulation system, and fibrinolysis, as well as depletion of coagulation inhibitors. These changes can also induce the formation of microvesicles and expression of tissue factor, leading to activation of WBCs, endothelial cell damage, and inflammatory response. Understanding the various factors that drive hypercoagulability as a thrombo-inflammatory mechanism in SCD can help provide explanations for the pathogenesis and other complications of the disease.

Acceptability to and Engagement With a Virtual Sickle Cell Trait Education Program (SCTaware): Single-Center Prospective Study.

BACKGROUND: Public health programs are tasked with educating the community on health topics, but it is unclear whether these programs are acceptable to learners. Currently, these programs are delivered via a variety of platforms including in-person, virtually, and over the telephone. Sickle cell trait (SCT) education for parents of children with this trait is one of many education programs provided by the Ohio Department of Health. The novel SCTaware videoconference education program was developed by a research team after central Ohio's standard program transitioned from in-person to telephone-only education during the COVID-19 pandemic. OBJECTIVE: Our objectives were to investigate the acceptability of the format and engagement with the SCTaware education and assess parental worry about having a child with SCT before and after receiving SCTaware. METHODS: This was a single-center, prospective study of English-speaking parents of children <3 years of age identified to have hemoglobin S trait by newborn screening. Parents who previously received SCT education by telephone, were able to be contacted, and had access to an electronic device capable of videoconferencing were eligible to complete surveys after receiving the virtual SCTaware education program. The SCTaware educator also completed a survey to assess participant engagement. Data were summarized descriptively and a McNemar test was used to compare parental worry before and after receiving SCTaware. RESULTS: In total, 55 participants completed follow-up surveys after receiving standard SCT telephone education and then completing SCTaware. Most (n=51) participants reported that the SCTaware content and visuals were very easy to understand (n=47) and facilitated conversation with the educator (n=42). All of them said the visuals were respectful and trustworthy, helped them understand content better, and that their questions were addressed. Nearly two-thirds (62%, n=34) reported that the pictures appeared very personal and applied to them. The educator noted most participants (n=45) were engaged and asked questions despite having to manage distractions during their education sessions. Many participants (n=33) reported some level of worry following telephone-only education; this was significantly reduced after receiving SCTaware (P<.001). CONCLUSIONS: Our results suggest that SCTaware is acceptable and engaging to parents. While telephone education may make SCT education more accessible, these findings suggest that many parents experience significant worry about their child with SCT after these sessions. A study to evaluate SCTaware's effectiveness at closing parents' SCT knowledge gaps is ongoing.

Phenotypic screening of the ReFRAME drug repurposing library to discover new drugs for treating sickle cell disease.

Stem cell transplantation and genetic therapies offer potential cures for patients with sickle cell disease (SCD), but these options require advanced medical facilities and are expensive. Consequently, these treatments will not be available for many years to the majority of patients suffering from this disease. What is urgently needed now is an inexpensive oral drug in addition to hydroxyurea, the only drug approved by the FDA that inhibits sickle-hemoglobin polymerization. Here, we report the results of the first phase of our phenotypic screen of the 12,657 compounds of the Scripps ReFRAME drug repurposing library using a recently developed high-throughput assay to measure sickling times following deoxygenation to 0% oxygen of red cells from sickle trait individuals. The ReFRAME library is a very important collection because the compounds are either FDA-approved drugs or have been tested in clinical trials. From dose-response measurements, 106 of the 12,657 compounds exhibit statistically significant antisickling at concentrations ranging from 31 nM to 10 µM. Compounds that inhibit sickling of trait cells are also effective with SCD cells. As many as 21 of the 106 antisickling compounds emerge as potential drugs. This estimate is based on a comparison of inhibitory concentrations with free concentrations of oral drugs in human serum. Moreover, the expected therapeutic potential for each level of inhibition can be predicted from measurements of sickling times for cells from individuals with sickle syndromes of varying severity. Our results should motivate others to develop one or more of these 106 compounds into drugs for treating SCD.

Plasma Levels of Acyl-Carnitines and Carboxylic Acids Correlate With Cardiovascular and Kidney Function in Subjects With Sickle Cell Trait.

Subjects with sickle cell trait (SCT) carry one copy of mutated ß-globin gene at position E6V at the origin of the production of sickle hemoglobin (HbS). Indeed, individuals with SCT have both normal hemoglobin and HbS, in contrast to patients with sickle cell disease who inherited of two copies of the mutated gene. Although SCT is generally benign/asymptomatic, carriers may develop certain adverse outcomes such as renal complications, venous thromboembolism, exercise-induced rhabdomyolysis … However, little is known about whether similar metabolic pathways are affected in individuals with SCT and whether these metabolic derangements, if present, correlate to clinically relevant parameters. In this study, we performed metabolomics analysis of plasma from individuals with sickle cell trait (n = 34) compared to healthy controls (n = 30). Results indicated a significant increase in basal circulating levels of hemolysis markers, mono- (pyruvate, lactate), di- and tri-carboxylates (including all Krebs cycle intermediates), suggestive of systems-wide mitochondrial dysfunction in individuals with SCT. Elevated levels of kynurenines and indoles were observed in SCT samples, along with increases in the levels of oxidative stress markers (advanced glycation and protein-oxidation end-products, malondialdehyde, oxylipins, eicosanoids). Increases in circulating levels of acyl-carnitines and fatty acids were observed, consistent with increased membrane lipid damage in individuals with sickle cell trait. Finally, correlation analyses to clinical co-variates showed that alterations in the aforementioned pathways strongly correlated with clinical measurements of blood viscosity, renal (glomerular filtration rate, microalbuminuria, uremia) and cardiovascular function (carotid-femoral pulse wave velocity, blood pressure).

Hematological, Biochemical Properties, and Clinical Correlates of Hemoglobin S Variant Disorder: A New Insight Into Sickle Cell Trait.

Background: The sickle cell trait (SCT) disorder possesses a clinical heterogeneity ranging from a symptomless condition to sudden death. This study aimed to develop a diagnostic approach that helps the characterization and identification of SCT from normal subjects and sickle cell disease (SCD) patients, and to assess its severity. Methods: Sixty controls, 24 SCD patients and 31 SCT subjects were assessed clinically, radiologically and by laboratory investigations. Results: Of the SCT subjects, 12.8% were symptomatic (3.2% anemic, 6.4% hemolytic crisis, and 3.2% painful crises). Anemia was normocytic in 66.6%, and normochromic and polychromatic in 33.4%. Significantly lower red blood cells (RBCs), hemoglobin (Hb), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), hematocrit (Hct), Shine and Lal index (SL), and hemoglobin A (Hb A), and higher mean corpuscular hemoglobin concentration (MCHC), red cell distribution width (RDW), Ricerca index (RI), and Huber-Herklotz index (HH) were found in SCT subjects compared with the controls. Hb A and hemoglobin S (Hb S) were excellent in discriminating SCT from SCD (cut-off for SCT > 50% and < 40%) followed by Hct, MCHC, Hb, Green and King index (GK), and England and Fraser index (EF) (cut-off for SCT > 33%, > 32, > 11, < 71, and < 10, respectively). Radiologically normal findings were detected in 87% of SCT subjects; they had nearly normal liver and renal function tests (except one case each). A schematic diagnostic paradigm for SCT was proposed. Conclusion: This study allowed understanding of SCT in various aspects, i.e., clinical, hematological, biochemical and radiological. Thus, it could help prevention of the Hb S variant disorder and proper management of carriers. This might be applied in pre-marital screening, particularly in those with family history of Hb S disorder.

Prevalence of Hemoglobin-S and Baseline Level of Knowledge on Sickle Cell Disease Among Pregnant Women Attending Antenatal Clinics in Dar-Es-Salaam, Tanzania.

Background: Sickle cell disease (SCD) is the single most important genetic cause of childhood mortality globally. Newborn screening (NBS) is the recommended intervention aimed at early identification of babies with SCD and their linkage to care. To ensure success of NBS, pregnant women need to have the required knowledge on SCD and therefore motivation to screen their babies. Objective: The aim of this study was to determine the prevalence of hemoglobin-S and assess the baseline level of knowledge on SCD among pregnant women attending antenatal clinics in urban settings in Dar-es-Salaam, Tanzania. Methods: This cross-sectional study was conducted between August 2020 and February 2021, involving 600 pregnant women at 20-28 weeks of gestation attending antenatal clinics at Buguruni Health Center, Mbagala Hospital, and Sinza Hospital in Dar-es-Salaam, Tanzania. We administered a structured questionnaire to all participants to assess socio-demographic characteristics and baseline level of knowledge on SCD, where those scoring 7 or higher out of 10 questions were considered to have good knowledge. We screened for SCD a total of 300 participants from two centers (Buguruni Health Center and Mbagala Hospital) by using Sickle SCAN point-of-care test (BioMedomics Inc., United States). We used SPSS version 23 to analyze the data. On determining the association between level of knowledge and socio-demographic factors, we used Pearson's Chi-square and multivariate logistic regression in ascertaining the strength of associations. Results: Of the 600 participants, the majority were of the age between 26 and 35 years (51%), with the parity of 1-3 children (55.8%) and secondary level of education (43%), while 56% were self-employed. Only 14.7% had good knowledge on SCD. The majority of the participants had ever heard of SCD (81.3%), most of them heard from the streets (42.4%), and only 2.4% heard from hospitals. Of all 600 study participants, only 2 (0.3%) knew their SCD status while 7.7% declared having a family history of SCD. A proficient level of knowledge on SCD is associated with a high level of education, occupation, and knowing personal status of SCD. Among 300 participants who were screened for SCD, 252 were Hb-AA (84%), 47 were Hb-AS (15.7%), and 1 (0.3%) was Hb-SS. Conclusion: Despite the high prevalence of hemoglobin-S among pregnant women attending antenatal clinics in urban settings in Tanzania, there is a poor level of knowledge on SCD and personal knowledge of SCD status. Maternal screening and health education on SCD should be included as part of the comprehensive package for health promotion at antenatal clinics.

Ácido úrico en las gestantes con diagnóstico de drepanocitosis y preeclampsia / Uric acid in pregnant women diagnosed with sickle cell disease and preeclampsia

RESUMEN Introducción: El ácido úrico es el producto final del ciclo de las purinas y es fundamental como marcador de enfermedad renal, la gota y la preeclampsia. Este biomarcador ejerce efectos potenciales en la placenta y el feto de la gestante con drepanocitosis. Objetivo: Describir los efectos potenciales que produce el ácido úrico en las gestantes con drepanocitosis. Métodos: Se revisó literatura en inglés y en español, a través del sitio web PubMed y el motor de búsqueda Google académico, en artículos publicados en los últimos cinco años. Se utilizaron como términos de búsqueda: preeclampsia, ácido úrico y riesgos en las embarazadas con drepanocitosis. Se analizaron los aspectos más relevantes del tema en la bibliografía revisada. Análisis y síntesis de la información: El incremento del ácido úrico añadido a la vasoclusión, la hipoxia y la necrosis tisular a nivel de la placenta son mecanismos invocados en el desarrollo de la preeclampsia y los índices de partos prematuros que presentan. Es de destacar que no tiene una trayectoria uniforme en todas las pacientes, sobre todo se observa una mejor evolución (con menor presencia de estas complicaciones) en aquellas pacientes que muestran genotipo, niveles de hemoglobina fetal y haplotipo de la hemoglobina S más favorable. Conclusiones: El ácido úrico constituye un biomarcador útil y de alarma en el diagnóstico de la preeclampsia, una de las peores complicaciones tanto para la vida materna como para su descendencia, al ser la gestante con drepanocitosis una paciente de muy alto riesgo de parto pretérmino, prematuridad, bajo peso al nacer, nacidos muertos e infarto placentario.

ABSTRACT Introduction: Uric acid is the end product of the purine cycle and is essential as a marker of kidney disease, gout and pre-eclampsia. This biomarker has potential effects on the placenta and fetus of a pregnant woman with sickle cell disease. Objective: To describe the potential effects of uric acid in pregnant women with sickle cell disease. Methods: Literature in English and Spanish was reviewed, through the PubMed website and the academic search engine Google, in articles published in the last five years. The search terms were: pre-eclampsia, uric acid and risks in pregnant women with sickle cell disease. The most relevant aspects of the subject were analyzed in the reviewed bibliography. Analysis and synthesis of information: The increase in uric acid added to vasoocclusion, hypoxia and tissue necrosis at the level of the placenta are mechanisms invoked in the development of pre-eclampsia and the rates of premature births they present. It is noteworthy that it does not have a uniform trajectory in all patients, especially a better evolution is observed, with less presence of these complications in those patients who show a more favorable genotype, fetal hemoglobin levels and hemoglobin S haplotype. Conclusions: Uric acid constitutes a useful and alarm biomarker in the diagnosis of pre-eclampsia, one of the worst complications both for maternal life and for her offspring, as the pregnant woman with sickle cell disease is a patient at a very high risk of preterm delivery. prematurity, low birth weight, stillbirths and placental infarction.

Morbilidad y mortalidad de 599 pacientes con drepanocitosis en el Instituto de Hematología e Inmunología / Morbidity and mortality of 599 sickle cell disease patients in the Institute of Hematology and Immunology

Introducción: La drepanocitosis es la anemia hemolítica congénita más común del mundo. Entre el 5 y 15 por ciento de la población mundial es portadora de la hemoglobina S y en Cuba, la frecuencia es de 3,08 por ciento, lo que representa un problema de salud pública. Objetivo: Caracterizar el cuadro clínico, el perfil hematológico y la probabilidad de supervivencia de los pacientes con drepanocitosis en el Instituto de Hematología e Inmunología. Método: Se realizó estudio descriptivo, longitudinal y retrospectivo, que incluyó todos los enfermos seguidos, al menos dos años, en la institución, entre enero de 1973 y diciembre del 2009. Resultados: Se incluyeron 599 pacientes (285 masculinos), 439 SS/Sβ0tal y 160 SC/Sβ+tal. El seguimiento medio fue de 17,6±9,5 años. Predominaron los pacientes entre 20 y 59 años. Los eventos clínicos más frecuentes fueron las crisis vasoclusivas dolorosas, las infecciones, el síndrome torácico agudo y las complicaciones hepáticas. Los valores de reticulocitos, plaquetas, leucocitos y hemoglobina fetal fueron significativamente mayores en los pacientes SS/Sβ0tal; no así la hemoglobina total que fue mayor en los SC/Sβ+tal. La probabilidad de supervivencia global de los pacientes a los 45 años fue de 69 por ciento. Los accidentes vasculares encefálicos (17,5 por ciento), las complicaciones hepáticas (17,5 por ciento) y las cardíacas (14,28 por ciento) fueron las principales causas de muerte. Conclusiones: La distribución demográfica y por hemoglobinopatías, el cuadro clínico, y el perfil hematológico fueron similares a los encontrados en pacientes de otras regiones geográficas, excepto la frecuencia de complicaciones hepáticas que fue mayor. La probabilidad de supervivencia fue similar con los mejores centros de atención en el mundo(AU)

Introduction: Sickle cell disease is the most common congenital hemolytic anemia in the world. Between 5 to 15 percent of the world population is a carrier of hemoglobin S and in Cuba, the frequency is 3.08 percent, which represents a public health problem. Objective: To characterize the clinical picture, the hematological profile, and the probability of survival of patients with sickle cell disease at the Institute of Hematology and Immunology. Method: A descriptive, longitudinal and retrospective study was carried out, which included all patients followed up for at least two years at the institution between January 1973 and December 2009. Results: 599 patients (285 male), 439 SS/Sβ0tal and 160 SC/Sβ+tal, were included. The mean follow-up was 17.6±9.5 years. Patients between 20 and 59 years old predominated. The most frequent clinical events were painful vasocclusive crises, infections, acute chest syndrome, and liver complications. The reticulocytes, platelets, leukocytes and fetal hemoglobin values ​​were significantly higher in the SS/Sβ0tal patients, but not the total hemoglobin, which was higher in the SC/Sβ+tal. The overall survival probability of patients at 45 years was 70 percent. Stroke (17.5 percent), liver complications (17.5 percent), and cardiac complications (14.28 percent) were the main causes of death. Conclusions: The demographic distribution and by hemoglobinopathies, the clinical events, and the hematological profile were similar to those found in patients from other geographic regions, except the frequency of liver complications, which was higher. The probability of survival was comparable with the best care centers in the world(AU)

Erythroid spectrin binding modulates peroxidase and catalase activity of heme proteins.

Hemoglobin oxidation due to oxidative stress and disease conditions leads to the generation of ROS (reactive oxygen species) and membrane attachment of hemoglobin in-vivo, where its redox activity leads to peroxidative damage of membrane lipids and proteins. Spectrin, the major component of the red blood cell (RBC) membrane skeleton, is known to interact with hemoglobin and, here this interaction is shown to increase hemoglobin peroxidase activity in the presence of reducing substrate ABTS (2', 2'-Azino-Bis-3-Ethylbenzothiazoline-6-Sulfonic Acid). It is also shown that in the absence of reducing substrate, spectrin forms covalently cross-linked aggregates with hemoglobin which display no peroxidase activity. This may have implications in the clearance of ROS and limiting peroxidative damage. Spectrin is found to modulate the peroxidase activity of different hemoglobin variants like A, E, and S, and of isolated globin chains from each of these variants. This may be of importance in disease states like sickle cell disease and HbE-ß-thalassemia, where increased oxidative damage and free globin subunits are present due to the defects inherent in the hemoglobin variants associated with these diseases. This hypothesis is corroborated by lipid peroxidation experiments. The modulatory role of spectrin is shown to extend to other heme proteins, namely catalase and cytochrome-c. Experiments with free heme and Raman spectroscopy of heme proteins in the presence of spectrin show that structural alterations occur in the heme moiety of the heme proteins on spectrin binding, which may be the structural basis of increased enzyme activity.

Pas-de-deux: African Plasmodium falciparum adaptations to sickle hemoglobin.

The molecular arms race between humans and Plasmodium falciparum in Africa resulted in selection of sickle-cell disease, which, on balance, protects heterozygote carriers against severe malaria. Band et al. discovered that parasites counter-adapt and can overcome disease resistance by identifying parasite genome signatures, termed P. falciparum sickle-associated (Pfsa) variants.

Novel Use of Hypoxia-Inducible Polymerizable Protein to Augment Chemotherapy for Pancreatic Cancer.

Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive malignancies and is the fourth leading cause of cancer-related deaths in the United States. Unfortunately, 80-85% of patients are diagnosed with unresectable, advanced stage tumors. These tumors are incurable and result in a median survival less than approximately six months and an overall 5-year survival rate of less than 7%. Whilst chemotherapy is a critical treatment, cure is not possible without surgical resection. The poor clinical outcomes in PDAC can be partially attributed to its dense desmoplastic stroma, taking up roughly 80% of the tumor mass. The stroma surrounding the tumor disrupts the normal architecture of pancreatic tissue leading to poor vascularization, high intratumoral pressure along with hypoxia and an acidic tumor microenvironment. This complicated microenvironment presents a significant challenge for drug delivery. The current manuscript discusses a novel approach to overcome many of these various obstacles. A complex of gemcitabine (GEM) and hemoglobin S (HbS) was formulated, which self-polymerizes under hypoxic and acidic conditions. When polymerized, HbS has the potential to break the tumor stroma, decrease intratumoral pressure, and therefore improve the treatment efficacy of standard therapy. Intratumoral injection of HbS with a fluorescent small molecule surrogate for GEM into a pancreatic tumor xenograft resulted in improved dissemination of the small molecule throughout the pancreatic tumor. The self-polymerization of HbS + GEM was significantly more effective than either agent individually at decreasing tumor size in an in vivo PDAC mouse model. These findings would suggest a clinical benefit from delivering the complex of GEM and HbS via direct injection by endoscopic ultrasound (EUS). With such a treatment option, patients with locally advanced disease would have the potential to become surgical candidates, offering them a chance for cure.