Myocarditis after Covid-19 Vaccination in a Large Health Care Organization.

BACKGROUND: Reports have suggested an association between the development of myocarditis and the receipt of messenger RNA (mRNA) vaccines against coronavirus disease 2019 (Covid-19), but the frequency and severity of myocarditis after vaccination have not been extensively explored. METHODS: We searched the database of Clalit Health Services, the largest health care organization (HCO) in Israel, for diagnoses of myocarditis in patients who had received at least one dose of the BNT162b2 mRNA vaccine (Pfizer-BioNTech). The diagnosis of myocarditis was adjudicated by cardiologists using the case definition used by the Centers for Disease Control and Prevention. We abstracted the presentation, clinical course, and outcome from the patient's electronic health record. We performed a Kaplan-Meier analysis of the incidence of myocarditis up to 42 days after the first vaccine dose. RESULTS: Among more than 2.5 million vaccinated HCO members who were 16 years of age or older, 54 cases met the criteria for myocarditis. The estimated incidence per 100,000 persons who had received at least one dose of vaccine was 2.13 cases (95% confidence interval [CI], 1.56 to 2.70). The highest incidence of myocarditis (10.69 cases per 100,000 persons; 95% CI, 6.93 to 14.46) was reported in male patients between the ages of 16 and 29 years. A total of 76% of cases of myocarditis were described as mild and 22% as intermediate; 1 case was associated with cardiogenic shock. After a median follow-up of 83 days after the onset of myocarditis, 1 patient had been readmitted to the hospital, and 1 had died of an unknown cause after discharge. Of 14 patients who had left ventricular dysfunction on echocardiography during admission, 10 still had such dysfunction at the time of hospital discharge. Of these patients, 5 underwent subsequent testing that revealed normal heart function. CONCLUSIONS: Among patients in a large Israeli health care system who had received at least one dose of the BNT162b2 mRNA vaccine, the estimated incidence of myocarditis was 2.13 cases per 100,000 persons; the highest incidence was among male patients between the ages of 16 and 29 years. Most cases of myocarditis were mild or moderate in severity. (Funded by the Ivan and Francesca Berkowitz Family Living Laboratory Collaboration at Harvard Medical School and Clalit Research Institute.).

Comparative histological analysis of spleens in pediatric patients with hemolytic anemias: Insights into the pathophysiological mechanisms of spleen destruction in sickle cell anemia.

While sickle cell anemia (SCA) and hereditary spherocytosis (HS) share common features of increased spleen erythrophagocytosis due to increased red blood cell (RBC) turnover, SCA is specifically characterized by susceptibility to infections. In this study, histological lesions in the spleens of pediatric patients with SCA were analyzed, in close correlation with past clinical history and comparatively to HS, healthy and transfused ß-thalassemia patients (TDT). An evaluation of red pulp elementary lesions (red pulp fibrosis, iron deposition, number of Gandy-Gamna, and RBC trapping) combined into a severity score was established, as well as B-cell follicles analysis. Quantification on digitalized slides of iron deposition, RBC trapping, and red pulp fibrosis was additionally performed. Spleens from 22 children with SCA, eight with HS, eight with TDT, and three healthy controls (HC) were analyzed. Median age at splenectomy was not different between SCA and HS patients, 6.05 years (range: 4.5-16.0) versus 4.75 (range: 2.2-9.5). Marked heterogeneity was found in SCA spleens in contrast to other conditions. Contrary to previous reports, B-cell follicles were generally preserved in SCA. While RBC trapping was significantly increased in both SCA and HS (compared to TDT and HC), quantitative fibrosis and overall red pulp severity score were significantly increased in SCA spleens compared to other conditions. Moreover, there was an inverse correlation between quantitative fibrosis and number of B-cell follicles, linking these two compartments as well as spleen fibrosis to infectious susceptibility in SCA, potentially through impaired red pulp macrophage scavenging and B-cell subpopulations defects.

Males with sickle cell disease have higher risks of cerebrovascular disease, increased inflammation, and a reduced response to hydroxyurea.

Biological sex is important. Male sex is associated with worse outcomes in most measures, including cerebrovascular disease, hospital admissions, and blood transfusions, but not survival. Females also appear to have a better response to hydroxyurea therapy, reduced markers of inflammation, and better liver function.

The pleiotropic effects of α-thalassemia on HbSS and HbSC sickle cell disease: Reduced erythrocyte cation co-transport activity, serum erythropoietin, and transfusion burden, do not translate into increased survival.

α-Thalassemia is one of the most important genetic modulators of sickle cell disease (SCD). Both beneficial and detrimental effects have been described previously. We use a 12-year data set on a large cohort of patients with HbSS (n = 411) and HbSC (n = 146) to examine a wide range of these clinical and laboratory associations. Our novel findings are that α-thalassemia strongly reduces erythrocyte potassium chloride co-transporter (KCC) activity in both HbSS and HbSC (p = .035 and p = .00045 respectively), suggesting a novel mechanism through which α-thalassemia induces a milder phenotype by reducing red cell cation loss. This may be particularly important in HbSC where reduction in mean cell hemoglobin concentration is not seen and where KCC activity has previously been found to correlate with disease severity. Additionally, we show that α-thalassemia not only increases hemoglobin in patients with HbSS (p = .0009) but also reduces erythropoietin values (p = .0005), demonstrating a measurable response to improved tissue oxygenation. We confirm the reno-protective effect of α-thalassemia in patients with HbSS, with reduced proteinuria (p = .003) and demonstrate a novel association with increased serum sodium (p = .0004) and reduced serum potassium values (p = 5.74 × 10-10 ). We found patients with α-thalassemia had a reduced annualized transfusion burden in both HbSS and HbSC, but α-thalassemia had no impact on annualized admission rates in either group. Finally, in a larger cohort, we report a median survival of 62 years in patients with HbSS (n = 899) and 80 years in those with HbSC (n = 240). α-thalassemia did not influence survival in HbSS, but a nonsignificant trend was seen in those with HbSC.

Ineffective erythropoiesis in sickle cell disease: new insights and future implications.

PURPOSE OF REVIEW: Sickle cell disease (SCD) is a hemolytic anemia caused by a point mutation in the ß globin gene leading to the expression of an abnormal hemoglobin (HbS) that polymerizes under hypoxic conditions driving red cell sickling. Circulating red cells have been extensively characterized in SCD, as their destruction and removal from peripheral blood are the major contributors to anemia. However, few reports showed cellular abnormalities during erythropoiesis in SCD, suggesting that anemia could also be influenced by defects of central origin. RECENT FINDINGS: El Hoss et al. demonstrated ineffective erythropoiesis (IE) in SCD and deciphered the molecular mechanism underlying cell death during the hemoglobin synthesis phase of terminal differentiation. They showed that HbS polymerization induces apoptosis of differentiating erythroblasts and that fetal hemoglobin rescues these cells through its antipolymerization function. SUMMARY: IE is the major cause of anemia in ß-thalassemia patients, and it is generally surmised that it contributes little to anemia of SCD. Recent reports demonstrate the occurrence of IE in SCD patients and show important alterations in the hematopoietic and erythroid niches, both in SCD patients and in the humanized Townes SCD mouse model. This implies that therapeutic strategies initially designed to improve red cell survival in the circulation of SCD patients would also positively impact erythropoiesis and bone marrow cellularity.

Fetal hemoglobin rescues ineffective erythropoiesis in sickle cell disease.

While ineffective erythropoiesis has long been recognized as a key contributor to anemia in thalassemia, its role in anemia of sickle cell disease (SCD) has not been critically explored. Using in vitro and in vivo derived human erythroblasts we assessed the extent of ineffective erythropoiesis in SCD. Modeling the bone marrow hypoxic environment, we found that hypoxia induces death of sickle erythroblasts starting at the polychromatic stage, positively selecting cells with high levels of fetal hemoglobin (HbF). Cell death was associated with cytoplasmic sequestration of heat shock protein 70 and was rescued by induction of HbF synthesis. Importantly, we document that in the bone marrow of SCD patients similar cell loss occurs during the final stages of terminal differentiation. Our study provides evidence for ineffective erythropoiesis in SCD and highlights an anti-apoptotic role for HbF during the terminal stages of erythroid differentiation. These findings imply that the beneficial effect on anemia of increased HbF levels is not only due to the increased life span of red cells but also a consequence of decreased ineffective erythropoiesis.

Oxidative stress activates red cell adhesion to laminin in sickle cell disease.

Vaso-occlusive crises are the hallmark of sickle cell disease (SCD). They are believed to occur in two steps, starting with adhesion of deformable low-dense red blood cells (RBCs), or other blood cells such as neutrophils, to the wall of post-capillary venules, followed by trapping of the denser RBCs or leukocytes in the areas of adhesion because of reduced effective lumen-diameter. In SCD, RBCs are heterogeneous in terms of density, shape, deformability and surface proteins, which accounts for the differences observed in their adhesion and resistance to shear stress. Sickle RBCs exhibit abnormal adhesion to laminin mediated by Lu/BCAM protein at their surface. This adhesion is triggered by Lu/BCAM phosphorylation in reticulocytes but such phosphorylation does not occur in mature dense RBCs despite firm adhesion to laminin. In this study, we investigated the adhesive properties of sickle RBC subpopulations and addressed the molecular mechanism responsible for the increased adhesion of dense RBCs to laminin in the absence of Lu/BCAM phosphorylation. We provide evidence for the implication of oxidative stress in post-translational modifications of Lu/BCAM that impact its distribution and cis-interaction with glycophorin C at the cell surface activating its adhesive function in sickle dense RBCs.

Induction of fetal hemoglobin synthesis by CRISPR/Cas9-mediated editing of the human ß-globin locus.

Naturally occurring, large deletions in the ß-globin locus result in hereditary persistence of fetal hemoglobin, a condition that mitigates the clinical severity of sickle cell disease (SCD) and ß-thalassemia. We designed a clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR-associated protein 9 (Cas9) (CRISPR/Cas9) strategy to disrupt a 13.6-kb genomic region encompassing the δ- and ß-globin genes and a putative γ-δ intergenic fetal hemoglobin (HbF) silencer. Disruption of just the putative HbF silencer results in a mild increase in γ-globin expression, whereas deletion or inversion of a 13.6-kb region causes a robust reactivation of HbF synthesis in adult erythroblasts that is associated with epigenetic modifications and changes in chromatin contacts within the ß-globin locus. In primary SCD patient-derived hematopoietic stem/progenitor cells, targeting the 13.6-kb region results in a high proportion of γ-globin expression in erythroblasts, increased HbF synthesis, and amelioration of the sickling cell phenotype. Overall, this study provides clues for a potential CRISPR/Cas9 genome editing approach to the therapy of ß-hemoglobinopathies.

Evaluation of Hypertrophic Cardiomyopathy: Newer Echo and MRI Approaches.

PURPOSE OF REVIEW: This review discusses the basic and evolving echocardiographic and cardiac magnetic resonance (CMR) approaches in the diagnosis and management of patients with hypertrophic cardiomyopathy (HCM). RECENT FINDINGS: Newer imaging technologies and techniques in both echocardiography and CMR have proved to add incremental value to our understanding of HCM. 3D reconstruction in echocardiography and CMR allows for more accurate morphological and volumetric assessment of the left ventricle. Echocardiographic and CMR-based left atrial assessment, including for its mechanical properties, has been shown to be correlated to outcomes and development of atrial fibrillation. Tissue characterization and scar burden quantification by late gadolinium enhancement on CMR has revolutionized our understanding of fibrotic processes in HCM and their contribution to disease severity and clinical outcomes. Cardiac imaging plays a crucial role in HCM patients. Using echocardiography and CMR as complementary modalities allows for improved diagnostics, optimization of treatment, and better prognostication.

Prognostic factors of disease severity in infants with sickle cell anemia: A comprehensive longitudinal cohort study.

In order to identify very early prognostic factors that can provide insights into subsequent clinical complications, we performed a comprehensive longitudinal multi-center cohort study on 57 infants with sickle cell anemia (55 SS; 2 Sß°) during the first 2 years of life (ClinicalTrials.gov: NCT01207037). Time to first occurrence of a severe clinical event-acute splenic sequestration (ASS), vaso-occlusive (VOC) event requiring hospitalization, transfusion requirement, conditional/ abnormal cerebral velocities, or death-was used as a composite endpoint. Infants were recruited at a mean age of 4.4 ±1 months. Median follow-up was 19.4 months. During the study period, 38.6% of infants experienced ≥1 severe event: 14% ASS, 22.8% ≥ 1 VOC (median age: 13.4 and 12.8 months, respectively) and 33.3% required transfusion. Of note, 77% of the cohort was hospitalized, with febrile illness being the leading cause for admission. Univariate analysis of various biomarkers measured at enrollment showed that fetal hemoglobin (HbF) was the strongest prognostic factor of subsequent severe outcome. Other biomarkers measured at enrolment including absolute neutrophil or reticulocyte counts, expression of erythroid adhesion markers, % of dense red cells, cellular deformability or ϒ-globin genetic variants, failed to be associated with severe clinical outcome. Multivariate analysis demonstrated that higher Hb concentration and HbF level are two independent protective factors (adjusted HRs (95% CI) 0.27 (0.11-0.73) and 0.16 (0.06-0.43), respectively). These findings imply that early measurement of HbF and Hb levels can identify infants at high risk for subsequent severe complications, who might maximally benefit from early disease modifying treatments.

Lopimune-induced mitochondrial toxicity is attenuated by increased uncoupling protein-2 level in treated mouse hepatocytes.

Although the protease inhibitor (PI) Lopimune has proven to be effective, no studies have examined the side effects of Lopimune on mitochondrial bioenergetics in hepatocytes. The objective of the present study is to evaluate mitochondrial respiration, production of reactive oxygen species (ROS) and expression of uncoupling protein-2 (UCP2) in mouse hepatocytes following Lopimune administration. Mitochondria were extracted from mouse liver using differential centrifugation and hepatocytes were isolated by the collagenase perfusion procedure. Mitochondrial respiration was measured using a Rank Brothers oxygen electrode. ROS production in hepatocytes was monitored by flow cytometry using a 2',7'-dichlorofluorescin diacetate probe and UCP2 protein expression was detected by Western blotting. We found that Lopimune induced a significant decrease of approximately 30% in the respiratory control ratio (RCR) starting from day 4 until day 9 of treatment. This decrease was due to an increase in state 4 respiration, reflecting an increase in mitochondrial proton leak. State 2 and state 3 respirations were not affected. Moreover, ROS production significantly increased by about 2-fold after day 1 of treatment and decreased after day 3, returning to the resting level on day 5. Interestingly, UCP2 which is absent from control hepatocytes, was expressed starting from day 4 of treatment. Our findings indicate that Lopimune-induced proton leak, mediated by UCP2, may represent a response to inhibit the production of ROS as a negative feedback regulatory mechanism. These results imply a potential involvement of UCP2 in the regulation of oxidative stress and add new insights into the understanding of mitochondrial toxicity induced by PIs.

Dynamic T-Wave Inversion: Unraveling an Athlete's Heart Mystery.

A 17-year-old athlete was initially diagnosed with presumed hypertrophic cardiomyopathy, marked by deep inferolateral T-wave inversions and mild anteroseptal hypertrophy on electrocardiogram and imaging studies. Remarkably, 6 years later, following detraining, all diagnostic signs completely resolved. This case underscores the significance of vigilant athlete follow-up.

Revolutionising healing: Gene Editing's breakthrough against sickle cell disease.

Recent advancements in gene editing illuminate new potential therapeutic approaches for Sickle Cell Disease (SCD), a debilitating monogenic disorder caused by a point mutation in the ß-globin gene. Despite the availability of several FDA-approved medications for symptomatic relief, allogeneic hematopoietic stem cell transplantation (HSCT) remains the sole curative option, underscoring a persistent need for novel treatments. This review delves into the growing field of gene editing, particularly the extensive research focused on curing haemoglobinopathies like SCD. We examine the use of techniques such as CRISPR-Cas9 and homology-directed repair, base editing, and prime editing to either correct the pathogenic variant into a non-pathogenic or wild-type one or augment fetal haemoglobin (HbF) production. The article elucidates ways to optimize these tools for efficacious gene editing with minimal off-target effects and offers insights into their effective delivery into cells. Furthermore, we explore clinical trials involving alternative SCD treatment strategies, such as LentiGlobin therapy and autologous HSCT, distilling the current findings. This review consolidates vital information for the clinical translation of gene editing for SCD, providing strategic insights for investigators eager to further the development of gene editing for SCD.