Mechanisms of Bone Impairment in Sickle Bone Disease

Effect of nutritional supplementation on bone mineral density in children with sickle cell disease: protocol for an open-label, randomised controlled clinical trial

INTRODUCTION

Children with sickle cell disease show a significant decrease in bone mineral density, an increase in resting energy expenditure of more than 15%, a decrease in fat and lean mass as well as a significant increase in protein turnover, particularly in bone tissue. This study aims to evaluate the effectiveness of an increase in food intake on bone mineral density and the clinical and biological complications of paediatric sickle cell disease.

METHODS AND ANALYSIS

The study is designed as an open-label randomised controlled clinical trial conducted in the Paediatrics Unit of the Orléans University Hospital Centre. Participants aged 3-16 years will be randomly divided into two groups: the intervention group will receive oral nutritional supplements (pharmacological nutritional hypercaloric products) while the control group will receive age-appropriate and gender-appropriate nutritional intake during 12 months. Total body less head bone mineral density will be measured at the beginning and the end of the trial. A rigorous nutritional follow-up by weekly 24 hours recall dietary assessment and planned contacts every 6 weeks will be carried out throughout the study. A school absenteeism questionnaire, intended to reflect the patient's school productivity, will be completed by participants and parents every 3 months. Blood samples of each patient of both groups will be stocked at the beginning and at the end of the trial, for future biological trial. Clinical and biological complications will be regularly monitored.

ETHICS AND DISSEMINATION

The protocol has been approved by the French ethics committee (Comité de Protection des Personnes Sud-Ouest et Outre-Mer 2, Toulouse; approval no: 2-20-092 id9534). Children and their parents will give informed consent to participate in the study before taking part. Results will be disseminated through peer-reviewed journals or international academic conferences.

TRIAL REGISTRATION NUMBER

NCT04754711.

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 β-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.

10-Year Cumulative Incidence and Indications for Revision Total Knee Arthroplasty Among Patients Who Have Sickle Cell Disease

BACKGROUND

Literature regarding total knee arthroplasty (TKA) outcomes in sickle cell disease (SCD) is limited. Moreover, 10-year survivorship of SCD implants is unknown. This study aimed to observe 10-year cumulative incidence and indications for revision TKA in patients who did and did not have SCD.

METHODS

Patients who underwent primary TKA were identified using a large national database. The SCD patients were matched by age, sex, and a comorbidity index to a control cohort in a 1:4 ratio. The 10-year cumulative incidence rates were determined using Kaplan-Meier survival analyses. Multivariable analyses were conducted using Cox proportional hazard modeling. Chi-squared analyses were conducted to compare indications for revision between cohorts. In total, 1,010 SCD patients were identified, 100,000 patients included in the unmatched control, and 4,020 patients included in the matched control.

RESULTS

Compared to the unmatched control cohort, SCD patients exhibited higher 10-year all-cause revision (HR: 1.86; P < .001) with higher proportions of revisions for periprosthetic joint infection (PJI) (P < .001), aseptic loosening (P < .001), and hematoma (P < .001). Compared to the matched control, SCD patients had higher 10-year all-cause revision (Hazard Ratio (HR): 1.39; P = .034) with a higher proportion of revisions for PJI (P = .044), aseptic loosening (P = .003), and hematoma (P = .019).

CONCLUSION

Independent of other comorbidities, SCD patients are more likely to undergo revisions for PJI, aseptic loosening, and hematoma compared to patients who do not have SCD. Due to the high-risk of these complications, perioperative and postoperative surgical optimization should be enforced in SCD patients.

Outcomes and long-term effects of hematopoietic stem cell transplant in sickle cell disease

INTRODUCTION

Hematopoietic stem cell transplant (HSCT) is the only readily available curative option for sickle cell disease (SCD). Cure rates following human leukocyte antigen (HLA)-matched related donor HSCT with myeloablative or non-myeloablative conditioning are >90%. Alternative donor sources, including haploidentical donor and autologous with gene therapy, expand donor options but are limited by inferior outcomes, limited data, and/or shorter follow-up and therefore remain experimental.

AREAS COVERED

Outcomes are improving with time, with donor type and conditioning regimens having the greatest impact on long-term complications. Patients with stable donor engraftment do not experience SCD-related symptoms and have stabilization or improvement of end-organ pathology; however, the long-term effects of curative strategies remain to be fully established and have significant implications in a patient's decision to seek therapy. This review covers currently published literature on HSCT outcomes, including organ-specific outcomes implicated in SCD, as well as long-term effects.

EXPERT OPINION

HSCT, both allogeneic and autologous gene therapy, in the SCD population reverses the sickle phenotype, prevents further organ damage, can resolve prior organ dysfunction in both pediatric and adult patients. Data support greater success with HSCT at a younger age, thus, curative therapies should be discussed early in the patient's life.

Low Bone Mass and Recurrent Fractures in Neurofibromatosis With Concomitant Hemoglobin SC Disease

Bone disease and bone loss are common features in certain monogenic diseases such as RASopathies, including neurofibromatosis (NF). Similarly, bone complications are frequent in hemoglobinopathies, another group of Mendelian diseases. This paper reports a young patient with both NF and hemoglobin SC (HbSC) diseases who had multiple vertebral fractures with osteopenia. We also discuss the cellular and pathophysiological mechanisms underlying both diseases and the factors responsible for bone pain and low bone mass in NF and hemoglobinopathies such as HbSC. This case emphasizes the importance of careful evaluation and management of osteoporosis in patients with HbSC and NF1, as both are relatively common monogenic diseases in certain communities.

Management of Older Adults with Sickle Cell Disease: Considerations for Current and Emerging Therapies

People with sickle cell disease (SCD) are living longer than ever before, with the median survival increasing from age 14 years in 1973, beyond age 40 years in the 1990s, and as high as 61 years in recent cohorts from academic centers. Improvements in survival have been attributed to initiatives, such as newborn screening, penicillin prophylaxis, vaccination against encapsulated organisms, better detection and treatment of splenic sequestration, and improved transfusion support. There are an estimated 100,000 people living with SCD in the United States and millions of people with SCD globally. Given that the number of older adults with SCD will likely continue to increase as survival improves, better evidence on how to manage this population is needed. When managing older adults with SCD (defined herein as age ≥ 40 years), healthcare providers should consider the potential pitfalls of extrapolating evidence from existing studies on current and emerging therapies that have typically been conducted with participants at mean ages far below 40 years. Older adults with SCD have historically had little to no representation in clinical trials; therefore, more guidance is needed on how to use current and emerging therapies in this population. This article summarizes the available evidence for managing older adults with SCD and discusses potential challenges to using approved and emerging drugs in this population.

Complete resolution of stage II avascular necrosis affecting three joints by hyperbaric oxygen in a patient with sickle cell disease: A case report

Avascular necrosis (AVN) or joint osteonecrosis is a debilitating complication of sickle cell disease, increasing the disease burden on both patients and healthcare systems. AVN can be radiologically categorized into early and late stages depending on the extent of the disease. Management of AVN is challenging and controversial. Generally, it includes conservative measures for early disease to preserve the joint for as long as possible and surgical management for more advanced diseases. Hyperbaric oxygen (HBO) therapy can be used as primary or adjunctive therapy for different medical disorders. Currently, the main rule of HBO in AVN is an adjunctive therapy to control symptoms and improve the quality of life of a patient; however, the concept of using HBO as a primary treatment choice for AVN in patients with sickle cell disease is not well evaluated yet. In this case study, we reported a 15-year-old boy with sickle cell disease who was suffering from stage II AVN in bilateral femoral and right shoulder joints. A total of 57 sessions of HBO resulted in the complete resolution of AVN in post-treatment MRI.

Sickle cell bone disease and response to intravenous bisphosphonates in children

Children with sickle cell disease (SCD) have the potential for extensive and early-onset bone morbidity. This study reports on the diversity of bone morbidity seen in children with SCD followed at three tertiary centers. IV bisphosphonates were effective for bone pain analgesia and did not trigger sickle cell complications.

INTRODUCTION

To evaluate bone morbidity and the response to intravenous (IV) bisphosphonate therapy in children with SCD.

METHODS

We conducted a retrospective review of patient records from 2003 to 2019 at three Canadian pediatric tertiary care centers. Radiographs, magnetic resonance images, and computed tomography scans were reviewed for the presence of avascular necrosis (AVN), bone infarcts, and myositis. IV bisphosphonates were offered for bone pain management. Bone mineral density was assessed by dual-energy X-ray absorptiometry (DXA).

RESULTS

Forty-six children (20 girls, 43%) had bone morbidity at a mean age of 11.8 years (SD 3.9) including AVN of the femoral (17/46, 37%) and humeral (8/46, 17%) heads, H-shaped vertebral body deformities due to endplate infarcts (35/46, 76%), and non-vertebral body skeletal infarcts (15/46, 32%). Five children (5/26, 19%) had myositis overlying areas of AVN or bone infarcts visualized on magnetic resonance imaging. Twenty-three children (8/23 girls) received IV bisphosphonate therapy. They all reported significant or complete resolution of bone pain. There were no reports of sickle cell hemolytic crises, pain crises, or stroke attributed to IV bisphosphonate therapy.

CONCLUSION

Children with SCD have the potential for extensive and early-onset bone morbidity. In this series, IV bisphosphonates were effective for bone pain analgesia and did not trigger sickle cell complications.

Revisiting anemia in sickle cell disease and finding the balance with therapeutic approaches

Chronic hemolytic anemia and intermittent acute pain episodes are the 2 hallmark characteristics of sickle cell disease (SCD). Anemia in SCD not only signals a reduction of red cell mass and oxygen delivery, but also ongoing red cell breakdown and release of cell-free hemoglobin, which together contribute to a number of pathophysiological responses and play a key role in the pathogenesis of cumulative multiorgan damage. However, although anemia is clearly associated with many detrimental outcomes, it may also have an advantage in SCD in lowering risks of potential viscosity-related complications. Until recently, clinical drug development for SCD has predominantly targeted a reduction in the frequency of vaso-occlusive crises as an endpoint, but increasingly, more attention is being directed toward addressing the contribution of chronic anemia to poor outcomes in SCD. This article aims to explore the complex pathophysiology and mechanisms of anemia in SCD, as well as the need to balance the benefits of raising hemoglobin levels with the potential risks of increasing blood viscosity, in the context of the current therapeutic landscape for anemia in SCD.

High Dickkopf-1 (DKK-1) levels are associated with chronic inflammation in children with Sickle Cell Disease

OBJECTIVES

Sickle bone disease (SBD) is a chronic complication of Sickle Cell Disease (SCD) whose pathogenesis is not completely understood. Chronic inflammation associated with SCD could alter bone remodeling. Our aim was to analyze the serum levels of bone remodeling markers in a group of SCD children to evaluate their involvement in the SBD.

METHODS

We enrolled 26 SCD subjects and 26 age-matched controls, who lived in the same geographic area. DKK-1, sclerostin, RANKL, and OPG serum levels were evaluated. Neutrophil-lymphocyte ratio (NLR) was also evaluated as a marker of inflammation.

RESULTS

The analysis of bone remodeling markers did not show any significant difference between the two groups except for DKK-1 levels that were significantly higher in the patients than controls (p<0.05). A significant direct correlation between NLR and DKK-1 (p=0.004) was found. An inverse correlation between NLR and osteocalcin (p=0.01) has also been observed.

CONCLUSIONS

The chronic inflammation, which represents a peculiar characteristic in SCD patients, would represent the primary causal agent of the activation of osteoblastogenesis inhibitors responsible of bone impairment in these subjects. Further studies will be needed to better explain the role of these inhibitors in SCD, to prevent or treat bone damage in this population.