Hematopoietic Stem Cell Transplantation Stabilizes Cerebral Vasculopathy in High-Risk Pediatric Sickle Cell Disease Patients: Evidence From a Referral Transplant Center

Longitudinal outcomes of chronically transfused adults with sickle cell disease and a history of childhood stroke

BACKGROUND

Many children with sickle cell disease (SCD) who suffer a stroke receive chronic transfusion therapy (CTT) indefinitely; however, their adulthood neurologic outcomes have not been reported. Understanding these outcomes is critical to inform decisions regarding curative therapy in childhood.

STUDY DESIGN AND METHODS

In this retrospective study, we described a cohort of adults with SCD and a history of childhood stroke who received care at a single center and compared their outcomes with matched subjects without childhood stroke using chi2 and Mann-Whitney U tests.

RESULTS

Of 42 subjects with childhood stroke, all received CTT for secondary stroke prophylaxis. Five (11%) developed recurrent stroke. The rate of stroke was similar in subjects with and without childhood stroke (0.7 vs. 1.1 per 100 person·years, p = .63). Both cohorts exhibited evidence of iron overload (median ferritin 2227 vs. 1409 ng/dL, p = .10) and alloimmunization (45% vs. 45%, p = 1.0), despite receiving care in a comprehensive SCD program.

DISCUSSION

For adults with SCD who had a childhood stroke, our results suggest CTT returns the risk of stroke to that of age-matched stroke naïve patients with SCD.

Stroke Prevention and Treatment for Youth with Sickle Cell Anemia: Current Practice and Challenges and Promises for the Future

PURPOSE OF REVIEW

Sickle cell anemia (SCA) is an autosomal recessive inherited hemoglobinopathy that results in a high risk of stroke. SCA primarily affects an underserved minority population of children who are frequently not receiving effective, multi-disciplinary, preventative care. This article reviews primary and secondary stroke prevention and treatment for children with SCA for the general adult and pediatric neurologist, who may play an important role in providing critical neurologic evaluation and care to these children.

RECENT FINDINGS

Primary stroke prevention is efficacious at reducing ischemic stroke risk, but it is not consistently implemented into clinical practice in the United States, resulting in these children remaining at high risk. Acute symptomatic stroke management requires neurology involvement and emergent transfusion to limit ischemia. Furthermore, while chronic transfusion therapy is a proven secondary preventative modality for those with prior symptomatic or silent cerebral infarcts, it carries significant burden. Newer therapies (e.g., stem cell therapies and voxelotor) deserve further study as they may hold promise in reducing stroke risk and treatment burden. Effective primary and secondary stroke prevention and treatment remain a challenge. Informing and engaging neurology providers to recognize and provide critical neurologic evaluation and treatment has potential to close care gaps.

Mesenchymal Stem Cell-Induced Neuroprotection in Pediatric Neurological Diseases: Recent Update of Underlying Mechanisms and Clinical Utility

Pediatric neurological diseases refer to a group of disorders that affect the nervous system in children. These conditions can have a significant impact on a child's development, cognitive function, motor skills, and overall quality of life. Stem cell therapy is a new and innovative approach to treat various neurological conditions by repairing damaged neurons and replacing those that have been lost. Mesenchymal stem cells (MSCs) have gained significant recognition in this regard due to their ability to differentiate into different cell types. MSCs are multipotent self-replicating stem cells known to render promising results in the treatment of stroke and spinal cord injury in adults. When delivered to the foci of damage in the central nervous system, stem cells begin to differentiate into neural cells under the stimulation of paracrine factors and secrete various neurotrophic factors (NTFs) like nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), and neurotrophin-3 (NT-3) that expedite the repair process in injured neurons. In the present review, we will focus on the therapeutic benefits of the MSC-based therapies in salient pediatric neurological disorders including cerebral palsy, stroke, and autism.

Effect of allogeneic hematopoietic stem cell transplantation on sickle cell disease-related organ complications: A systematic review and meta-analysis

Sickle cell disease (SCD)-related organ complications are a major cause of morbidity and mortality in patients with SCD. We sought to assess whether hematopoietic stem cell transplantation (HSCT) stabilizes, attenuates, or exacerbates organ decline. We performed a systematic review and meta-analysis of trials investigating organ function before and after HSCT in patients with SCD. We searched MEDLINE/PubMed and EMBASE up to September 21, 2023. Continuous data were expressed as standardized mean difference (SMD) and pooled in a weighted inverse-variance random-effects model; binomial data were expressed as risk ratio (RR) using the Mantel-Haenszel random-effects meta-analyses. Of 823 screened studies, 34 were included in this review. Of these, 17 (774 patients, 23.6% adults, 86.3% HLA-identical sibling donor, 56.7% myeloablative conditioning regimen) were included in the meta-analyses. Pulmonary function remained stable. Mean tricuspid regurgitant jet velocity decreased but did not reach statistical significance. In children, estimated glomerular filtration rate decreased (SMD -0.80, p = .01), and the presence of proteinuria increased (RR 2.00, p = <.01), while splenic uptake and phagocytic function improved (RR 0.31, p = <.01; RR 0.23, p = <.01). Cerebral blood flow improved (SMD -1.39, p = <.01), and a low incidence of stroke after transplantation in high-risk patients was found. Retinopathy and avascular osteonecrosis were investigated in only one study, showing no significant changes. While HSCT can improve some SCD-related organ dysfunctions, transplantation-related toxicity may have an adverse effect on others. Future research should focus on identifying individuals with SCD who might benefit most from HSCT and which forms of organ damage are more likely to exacerbate post-transplantation.

The effectiveness of hematopoietic stem cell transplantation in treating pediatric sickle cell disease: Systematic review and meta-analysis

Background

Patients with sickle cell disease (SCD) have just one recognized curative therapy option: hematopoietic stem cell transplantation (HSCT), which results in a long-lasting improvement in the clinical phenotype. Here, we assessed the effectiveness of HSCT in treating children with SCD by a systematic review and meta-analysis.

Methods

Up until January 2024, a comprehensive search was done using Web of Science, CINAHL, Embase, Google Scholar, Cochrane Library, PubMed/Medline, and Embase. Two reviewers worked separately to extract the data, and Newcastle-Ottawa Quality Assessment tool was used to assess the research's quality. The outcomes analyzed were Overall survival (OS), event-free survival (EFS), graft failure (GF) and mortality.

Results

Nineteen papers satisfied our inclusion requirements and were assessed to be of fair quality. The pooled rate of OS was high (92%; 95% CI: 90.3%-93.5%). Similar finding was detected for EFS (85.8%; 95% CI: 83.7%-87.7%). In the other hand, pooled rates of GF and mortality were 6.9% (95% CI: 5.3%-8.9%) and 7.4% (95% CI: 5%-10.7%), respectively. A significant publication bias was detected for OS, EFS and GF outcomes. Subgroups analysis showed that study design was the major source of heterogeneity.

Conclusion

Our results show that HSCT is effective and safe, with pooled survival rates above 90%. It is important to assess innovative tactics in light of the alarming GF and mortality rates.

Reversal of Cerebral Arteriopathy Post-Hematopoietic Stem Cell Transplant for Sickle Cell Disease

Sickle cell disease (SCD) is a chronic hematologic disorder which causes progressive cerebral arteriopathy beginning in childhood. As a result, arterial ischemic stroke is a major cause of morbidity and mortality in SCD, and SCD is a leading cause of childhood stroke worldwide. Allogenic hematopoietic stem cell transplant (HSCT) may be curative for individuals with SCD. Long-term outcomes and effects are currently being studied. In this report, we describe a child with SCD who presented with arterial ischemic stroke at 6 years of age and was found to have a severe form of cerebral large vessel arteriopathy by catheter-directed angiography. The patient initially underwent revascularization surgery by indirect superficial temporal artery to middle cerebral artery bypass, and 1 year later, he underwent curative HSCT. Approximately 3 years after HSCT, repeat catheter-directed angiography revealed a striking reversal of cerebral large vessel arteriopathy. This article reveals a previously unrecognized and potentially beneficial effect of HSCT that may ameliorate cerebral large vessel arteriopathy and improve cerebrovascular health for children with SCD.

Moyamoya Syndrome in Children With Sickle Cell Disease in Saudi Arabia: A Single-Center Experience

Background Sickle cell disease (SCD) is relatively common in Saudi Arabia. Its neurologic complications such as stroke and Moyamoya syndrome (MMS) can be severe and devastating. Such complications can be minimized by modern investigative tools such as transcranial Doppler (TCD) ultrasound, which is unavailable in many high-risk places. Our aim is to investigate the prevalence and characteristics of these complications in children with SCD in our center where TCD is not available. Methods We conducted a retrospective record review of children with SCD admitted to the pediatric ward and visited the pediatric hematology outpatient clinic of King Fahad Military Medical Complex, Dhahran, Saudi Arabia, from January 2010 to December 2021. The target population was children aged six months to 14 years with SCD and a history of stroke or transient ischemic attacks (TIAs). Their magnetic resonance imaging/magnetic resonance angiography (MRI/MRA) of the brain radiographic features were reviewed. A descriptive analysis was used to summarize the demographic characteristics and clinical features of patients with and without MMS. Results Twenty-six children (out of 385 with sickle cell anemia, originating mainly from the southwestern and eastern provinces of Saudi Arabia) experienced an overt stroke with an overall prevalence of 6.7%. All patients with stroke were originally from the Southwestern province. Their genotype was SS, and the median age at the onset of the first stroke was six years (IQR: 5.5). The main presenting symptoms were seizures (57.7%), motor weakness (42.3%), headache (15.3%), cranial nerve palsies (11.5%), cognitive deficit (7.6%), and dysphasia (3.8%). The majority of strokes were ischemic (92.3%). MMS was detected in 61.5% and was seen at the onset of the first stroke in all patients with this MRA abnormality. Seven children with moyamoya (43.8%) had recurrent strokes. Conclusion In this study, the prevalence of overt stroke is 9% in children with SCD originating from the southwestern region of Saudi Arabia (26/286), and 61.5% of them (16/26) had MMS. It is absent in the children of Eastern origin (99 children). In places lacking TCD facilities, further studies are required to determine if MRA brain screenings of children with SCD may detect MMS before the onset of stroke and help start protective therapy.