Gene Editing for Sickle Cell Disease and Transfusion Dependent Thalassemias- A cure within reach

How we forecast tomorrow's haemovigilance

The field of haemovigilance continues to develop, building on more than forty years of international experience. This review considers the current scope and activities of haemovigilance around the world and explores aspects of preparation for the advent of new blood products and alternative therapies to transfusion; new tools for data acquisition (including patient- and donor-reported outcomes, and data from 'wearables') and the analysis and communication of haemovigilance results.

Current challenges and new approaches to implementing optimal management of sickle cell disease in sub-Saharan Africa

Sickle cell disease (SCD) is the most common life-threatening monogenic disorder in the world. The disease is highly prevalent in malaria endemic areas with over 75% of patients residing in Sub-Saharan Africa (SSA). It is estimated that, without proper care, up to 90% of children with SCD will not celebrate their fifth birthday. Early identification and enrolment into comprehensive care has been shown to reduce the morbidity and mortality related with SCD complications. However, due to resource constraints, the SSA is yet to implement universal newborn screening programs for SCD. Furthermore, care for patients with SCD in the region is hampered by the shortage of qualified healthcare workers, lack of guidelines for the clinical management of SCD, limited infrastructure for inpatient and outpatient care, and limited access to blood and disease modifying drugs such as Hydroxyurea which contribute to poor clinical outcomes. Curative options such as bone marrow transplant and gene therapy are expensive and not available in many SSA countries. In addressing these challenges, various initiatives are ongoing in SSA which aim to enhance awareness on SCD, improve patient identification and retention to care, harmonize the standards of care for SCD, improve the skills of healthcare workers and conduct research on pertinent areas in SCD in the SSA context. Fortifying these measures is paramount to improving the outcomes of SCD in SSA.

Normal and dysregulated crosstalk between iron metabolism and erythropoiesis

Erythroblasts possess unique characteristics as they undergo differentiation from hematopoietic stem cells. During terminal erythropoiesis, these cells incorporate large amounts of iron in order to generate hemoglobin and ultimately undergo enucleation to become mature red blood cells, ultimately delivering oxygen in the circulation. Thus, erythropoiesis is a finely tuned, multifaceted process requiring numerous properly timed physiological events to maintain efficient production of 2 million red blood cells per second in steady state. Iron is required for normal functioning in all human cells, the erythropoietic compartment consuming the majority in light of the high iron requirements for hemoglobin synthesis. Recent evidence regarding the crosstalk between erythropoiesis and iron metabolism sheds light on the regulation of iron availability by erythroblasts and the consequences of insufficient as well as excess iron on erythroid lineage proliferation and differentiation. In addition, significant progress has been made in our understanding of dysregulated iron metabolism in various congenital and acquired malignant and non-malignant diseases. Finally, we report several actual as well as theoretical opportunities for translating the recently acquired robust mechanistic understanding of iron metabolism regulation to improve management of patients with disordered erythropoiesis, such as anemia of chronic inflammation, β-thalassemia, polycythemia vera, and myelodysplastic syndromes.

Combined approaches for increasing fetal hemoglobin (HbF) and de novo production of adult hemoglobin (HbA) in erythroid cells from β-thalassemia patients: treatment with HbF inducers and CRISPR-Cas9 based genome editing

Genome editing (GE) is one of the most efficient and useful molecular approaches to correct the effects of gene mutations in hereditary monogenetic diseases, including β-thalassemia. CRISPR-Cas9 gene editing has been proposed for effective correction of the β-thalassemia mutation, obtaining high-level "de novo" production of adult hemoglobin (HbA). In addition to the correction of the primary gene mutations causing β-thalassemia, several reports demonstrate that gene editing can be employed to increase fetal hemoglobin (HbF), obtaining important clinical benefits in treated β-thalassemia patients. This important objective can be achieved through CRISPR-Cas9 disruption of genes encoding transcriptional repressors of γ-globin gene expression (such as BCL11A, SOX6, KLF-1) or their binding sites in the HBG promoter, mimicking non-deletional and deletional HPFH mutations. These two approaches (β-globin gene correction and genome editing of the genes encoding repressors of γ-globin gene transcription) can be, at least in theory, combined. However, since multiplex CRISPR-Cas9 gene editing is associated with documented evidence concerning possible genotoxicity, this review is focused on the possibility to combine pharmacologically-mediated HbF induction protocols with the "de novo" production of HbA using CRISPR-Cas9 gene editing.