Modulation of the HIF2α-NCOA4 axis in enterocytes attenuates iron loading in a mouse model of hemochromatosis.

Intestinal iron absorption is activated during increased systemic demand for iron. The best-studied example is iron deficiency anemia, which increases intestinal iron absorption. Interestingly, the intestinal response to anemia is very similar to that of iron overload disorders, as both the conditions activate a transcriptional program that leads to a hyperabsorption of iron via the transcription factor hypoxia-inducible factor 2α (HIF2α). However, pathways for selective targeting of intestine-mediated iron overload remain unknown. Nuclear receptor coactivator 4 (NCOA4) is a critical cargo receptor for autophagic breakdown of ferritin and the subsequent release of iron, in a process termed ferritinophagy. Our work demonstrates that NCOA4-mediated intestinal ferritinophagy is integrated into systemic iron demand via HIF2α. To demonstrate the importance of the intestinal HIF2α/ferritinophagy axis in systemic iron homeostasis, whole-body and intestine-specific NCOA4-/- mouse lines were generated and assessed. The analyses revealed that the intestinal and systemic response to iron deficiency was not altered after disruption of intestinal NCOA4. However, in a mouse model of hemochromatosis, ablation of intestinal NCOA4 was protective against iron overload. Therefore, NCOA4 can be selectively targeted for the management of iron overload disorders without disrupting the physiological processes involved in the response to systemic iron deficiency.

A regional anticoagulation program improves safety and outcomes for both children and adults.

BACKGROUND: Evidence-based anticoagulation programs usually serve a local, adult patient population. Here we report outcomes for a regional combined pediatric-adult program. AIMS: The aims of this study were: (1) Compare the pre- vs. post-implementation quality of therapy (% time in therapeutic range (%TTR) and compliance). (2) Assess anticoagulant-relevant outcomes (bleeding and thrombotic complications). METHODS: Data were collected for the years 2014-2019. Rosendaal linear interpolation was used to calculate %TTR. Bleeding complications were categorized using ISTH-SSC standard nomenclature and new thrombotic events were reviewed. RESULTS: The patients were divided into a long-term warfarin group (N = 308), 80.2% of whom had cardiac-related therapeutic indications (median age 24y), and a second group (N = 114) comprised of short-term and non-warfarin long-term anticoagulation (median age 16y). Median %TTR for those on long-term warfarin was 78.9%. The incidence of major and clinically relevant non-major bleeding events was 1.65 and 2.43 /100 person-years of warfarin use, respectively. Thromboembolism (TE) incidence was 0.78/100 patient-years of warfarin use. Neither bleeding nor thrombosis was associated with %TTR (p = 0.48). Anticoagulant indication was the only variable associated with bleeding risk (p = 0.005). The second group had no on-therapy TE events but 7.9% experienced bleeding. Complete data were available for a randomly sampled pre-program warfarin group (N = 26). Median %TTR improved from 17.5 to 87% pre- vs. post-implementation. Similarly, compliance (defined as ≥ 1 INR/month) improved by 34.3%. CONCLUSIONS: In conclusion, this program significantly improved and sustained %TTR and compliance. The lack of association between bleeding and thrombosis events and %TTR may be related to the high median %TTR (> 70%) achieved by this approach.

Drive-Through Anticoagulation Clinic During the COVID-19 Pandemic.

An innovative approach to anticoagulation management during the COVID-19 pandemic was used at our center that allowed patients to stay in their vehicle while our anticoagulation advanced practice registered nurse obtained blood for point-of-care international normalized ratio (INR) testing while education and counseling were completed. A significant improvement in the median percentage of INR within the therapeutic range was observed among the patients who used the drive-through clinic. A small group of patients improved compliance to anticoagulation monitoring. Clinical care models, such as this clinic approach may improve patient compliance and adherence to anticoagulation beyond the pandemic needs.

Line Associated Thrombosis in Pediatric Patients With NF-κB Pathway Variants.

Our report explores the complex role that nuclear factor-kappa B (NF-κB) plays in thrombosis formation, inflammation, and immunity; while additionally demonstrating that patients with NF-κB pathway pathogenic variants appear to carry a substantial thrombotic risk, particularly when secondary thrombotic risk factors are present. We propose that prophylactic anticoagulation should be strongly considered in such patients during high-risk situations and provide additional hematologic management strategies for those with NF-κB pathway alterations. We hope our work also calls to attention the potential need for a broader assessment of venous thromboembolism risk in patients with immune dysregulation to better delineate which patient populations may benefit from anticoagulation prophylaxis.

The evolution of recombinant factor replacement for hemophilia.

Hemophilia A and Hemophilia B are the most common of the severe bleeding disorders and are caused by a deficiency in blood clotting factor VIII or factor IX respectively. Factor replacement therapy has been the cornerstone of treatment to treat life threatening bleeds and prevent joint disease. The treatment of hemophilia has evolved tremendously over the past five decades from fresh frozen plasma as the only available therapy to more specific plasma-derived and recombinant-derived factor replacement. Now due to innovations in bioengineering, there are even more efficacious factor replacement options available to patients. Here we review these recent advancements and their impact on the treatment and management of hemophilia.

Multiple Cavitary Lung Lesions in an Adolescent: Case Report of a Rare Presentation of Nodular Lymphocyte Predominant Hodgkin Lymphoma.

A 14-year-old male patient presented with a nonproductive cough, weight loss, fatigue, and malaise. A chest radiograph showed large bilateral cavitary lung lesions in both upper and lower lobes that failed to improve with antibiotics and anti-inflammatory medications. Infectious and rheumatologic work-ups were negative. Thoracoscopic lung biopsies were diagnostic for nodular lymphocyte predominant Hodgkin lymphoma (NLPHL). The patient received combination chemotherapy and immunotherapy based on current treatment standards with an excellent clinical response. NLPHL is a rare B-cell lymphoma that typically presents as peripheral lymph nodal disease, clinically distinct from classical Hodgkin lymphoma. The prognosis of NLPHL in children is favorable, although relapse rates are high. This case details several unique features of NLPHL and describes the presentation, diagnosis, and treatment of an adolescent male with a rare pulmonary and cervical NLPHL, the first such case described in a pediatric patient.

Multisystem Inflammatory Syndrome in Children and Cardiac Involvement: A Quaternary Center Experience.

We prospectively analyzed clinical and laboratory characteristics associated with cardiac involvement and severe presentation in multisystem inflammatory syndrome in children. Of 146 patients, 66 (45.2%) had cardiac dysfunction and 26 (17.8%) had coronary artery abnormalities. Lower serum albumin levels, absolute lymphocyte and platelet counts, and elevated ferritin, fibrinogen, d-dimer and interleukin-6 levels were associated with cardiac dysfunction. Possible treatment complications were identified.

Intracardiac thrombi in pediatrics: anticoagulation approach and treatment outcomes.

Background: Intracardiac thrombi (ICT) are associated with significant morbidity and mortality. Anticoagulation is the first line of treatment and may be complemented by thrombectomy or thrombolysis. However, optimal anticoagulant duration remains ill-defined. High-risk features of ICT that may warrant long-term anticoagulation therapy have not been established. Objectives: To describe anticoagulation duration and patterns of ICT resolution. To identify potential risk factors for persistent ICT despite anticoagulation. Methods: A single-institution retrospective chart review identified patients diagnosed with ICT by echocardiogram between January 2014 and March 2022. Descriptive statistics and logistic regression were used. Results: Fifty-one patients with ICT were identified. Median age at diagnosis was 9.2 years (IQR, 0.4-15.2). The most common underlying diagnoses were congenital heart disease (41%), infection (25%), and malignancy (24%). The majority of ICT were in the right atrium (n = 30). The median longest ICT dimension was 1.5 cm (range, 0.4-4.0). The median duration of anticoagulation was 4.3 months (IQR, 2.2-9.1). Among 48 patients who received anticoagulation as first-line treatment, 32 had partial or complete response with 3 to 6 months of anticoagulation, while remaining 16 patients had no response to anticoagulation. Patients with a central venous line had a delayed resolution of ICT [hazards ratio = 0.45 (95% CI, 0.22-0.93)]. Conclusion: Our study demonstrates the wide variability in duration of anticoagulation for children with ICT. Majority of the individuals benefit from 3-to-6 month treatment; however, individuals with a central venous line may benefit from a longer course of anticoagulation. Further large-scale studies are recommended to validate our findings.

Hemostatic and Thrombotic Considerations in the Diagnosis and Management of Childhood Arterial Ischemic Stroke: A Narrative Review.

Although rare in children, arterial ischemic stroke (AIS) is associated with increased mortality and neurological morbidity. The incidence of AIS after the neonatal period is approximately 1-2/100,000/year, with an estimated mortality of 3-7%. A significant proportion of children surviving AIS experience life-long neurological deficits including hemiparesis, epilepsy, and cognitive delays. The low incidence of childhood AIS coupled with atypical clinical-presentation and lack of awareness contribute to delay in diagnosis and consequently, the early initiation of treatment. While randomized-clinical trials have demonstrated the efficacy and safety of reperfusion therapies including thrombolysis and endovascular thrombectomy in appropriately-selected adult patients, similar data for children are unavailable. Consequently, clinical decisions surrounding reperfusion therapy in childhood AIS are either extrapolated from adult data or based on local experience. The etiology of childhood AIS is multifactorial, often occurring in the setting of both acquired and congenital risk-factors including thrombophilia. While multiple studies have investigated the association of thrombophilia with incident childhood AIS, its impact on stroke recurrence and therefore duration and intensity of antithrombotic therapy is less clear. Despite these limitations, a significant progress has been made over the last decade in the management of childhood AIS. This progress can be attributed to international consortiums, and in selected cohorts to federally-funded clinical trials. In this narrative review, the authors have systematically appraised the literature and summarize the hemostatic and thrombotic considerations in the diagnosis and management of childhood AIS focusing on the evidence supporting reperfusion therapies, relevance of thrombophilia testing, and duration and drug choices for secondary-prophylaxis.

Microbial Metabolite Signaling Is Required for Systemic Iron Homeostasis.

Iron is a central micronutrient needed by all living organisms. Competition for iron in the intestinal tract is essential for the maintenance of indigenous microbial populations and for host health. How symbiotic relationships between hosts and native microbes persist during times of iron limitation is unclear. Here, we demonstrate that indigenous bacteria possess an iron-dependent mechanism that inhibits host iron transport and storage. Using a high-throughput screen of microbial metabolites, we found that gut microbiota produce metabolites that suppress hypoxia-inducible factor 2α (HIF-2α) a master transcription factor of intestinal iron absorption and increase the iron-storage protein ferritin, resulting in decreased intestinal iron absorption by the host. We identified 1,3-diaminopropane (DAP) and reuterin as inhibitors of HIF-2α via inhibition of heterodimerization. DAP and reuterin effectively ameliorated systemic iron overload. This work provides evidence of intestine-microbiota metabolic crosstalk that is essential for systemic iron homeostasis.