RESUMEN
Consistent with studies showing a high prevalence of the Duffy null phenotype among healthy Black Americans, this retrospective study found that Duffy null was present in >75% of a young and contemporary cohort of children with sickle cell disease (SCD) in the United States. Despite the potential for this phenotype to impact absolute neutrophil counts, hydroxyurea (HU) dosing, and outcomes, it was not associated with being prescribed a lower HU dose or having increased acute SCD visits early in the HU treatment course. Future studies are needed to confirm these findings in older children with SCD.
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Anemia de Células Falciformes , Antidrepanocíticos , Sistema del Grupo Sanguíneo Duffy , Hidroxiurea , Humanos , Hidroxiurea/uso terapéutico , Hidroxiurea/administración & dosificación , Anemia de Células Falciformes/tratamiento farmacológico , Anemia de Células Falciformes/epidemiología , Masculino , Femenino , Estudios Retrospectivos , Preescolar , Estados Unidos/epidemiología , Niño , Sistema del Grupo Sanguíneo Duffy/genética , Prevalencia , Antidrepanocíticos/uso terapéutico , Lactante , Receptores de Superficie Celular/genética , AdolescenteRESUMEN
BACKGROUND: In 2014, germline signal transducer and activator of transcription (STAT) 3 gain-of-function (GOF) mutations were first described to cause a novel multisystem disease of early-onset lymphoproliferation and autoimmunity. OBJECTIVE: This pivotal cohort study defines the scope, natural history, treatment, and overall survival of a large global cohort of patients with pathogenic STAT3 GOF variants. METHODS: We identified 191 patients from 33 countries with 72 unique mutations. Inclusion criteria included symptoms of immune dysregulation and a biochemically confirmed germline heterozygous GOF variant in STAT3. RESULTS: Overall survival was 88%, median age at onset of symptoms was 2.3 years, and median age at diagnosis was 12 years. Immune dysregulatory features were present in all patients: lymphoproliferation was the most common manifestation (73%); increased frequencies of double-negative (CD4-CD8-) T cells were found in 83% of patients tested. Autoimmune cytopenias were the second most common clinical manifestation (67%), followed by growth delay, enteropathy, skin disease, pulmonary disease, endocrinopathy, arthritis, autoimmune hepatitis, neurologic disease, vasculopathy, renal disease, and malignancy. Infections were reported in 72% of the cohort. A cellular and humoral immunodeficiency was observed in 37% and 51% of patients, respectively. Clinical symptoms dramatically improved in patients treated with JAK inhibitors, while a variety of other immunomodulatory treatment modalities were less efficacious. Thus far, 23 patients have undergone bone marrow transplantation, with a 62% survival rate. CONCLUSION: STAT3 GOF patients present with a wide array of immune-mediated disease including lymphoproliferation, autoimmune cytopenias, and multisystem autoimmunity. Patient care tends to be siloed, without a clear treatment strategy. Thus, early identification and prompt treatment implementation are lifesaving for STAT3 GOF syndrome.
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Enfermedades del Sistema Inmune , Síndromes de Inmunodeficiencia , Niño , Humanos , Autoinmunidad/genética , Estudios de Cohortes , Mutación con Ganancia de Función , Síndromes de Inmunodeficiencia/genética , Mutación , Factor de Transcripción STAT3/genética , Proliferación Celular , LinfocitosRESUMEN
The congenital sideroblastic anemias (CSAs) are a heterogeneous group of inherited disorders of erythropoiesis characterized by pathologic deposits of iron in the mitochondria of developing erythroblasts. Mutations in the mitochondrial glycine carrier SLC25A38 cause the most common recessive form of CSA. Nonetheless, the disease is still rare, there being fewer than 70 reported families. Here we describe the clinical phenotype and genotypes of 31 individuals from 24 families, including 11 novel mutations. We also review the spectrum of reported mutations and genotypes associated with the disease, describe the unique localization of missense mutations in transmembrane domains and account for the presence of several alleles in different populations.
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Anemia Sideroblástica/congénito , Genotipo , Proteínas de Transporte de Membrana Mitocondrial/genética , Mutación , Fenotipo , Preescolar , Femenino , Humanos , Lactante , Recién Nacido , MasculinoRESUMEN
The North American Pediatric Aplastic Anemia Consortium (NAPAAC) is a group of pediatric hematologist-oncologists, hematopathologists, and bone marrow transplant physicians from 46 institutions in North America with interest and expertise in aplastic anemia, inherited bone marrow failure syndromes, and myelodysplastic syndromes. The NAPAAC Bone Marrow Failure Diagnosis and Care Guidelines Working Group was established with the charge of harmonizing the approach to the diagnostic workup of aplastic anemia in an effort to standardize best practices in the field. This document outlines the rationale for initial evaluations in pediatric patients presenting with signs and symptoms concerning for severe aplastic anemia.
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Anemia Aplásica/diagnóstico , Anemia Aplásica/patología , Médula Ósea/patología , Niño , Diagnóstico Diferencial , Hemoglobina Fetal/análisis , Antígenos HLA/análisis , Humanos , América del Norte , Índice de Severidad de la EnfermedadRESUMEN
BACKGROUND AND OBJECTIVE: Many children receiving chemotherapy struggle with therapy-induced side effects. To date, there has been no literature investigating the needs, knowledge, or implementation of osteopathic manipulative treatments (OMT) as a supportive care option in pediatric oncology. We hypothesized that pediatric oncology clinicians, caregivers, and patients have (a) limited knowledge of OMT and (b) dissatisfaction with current supportive care options and (c) would be interested in having OMT available during chemotherapy, once educated. METHODS: Participants included three cohorts: (1) children aged ≥ 9 years, diagnosed with cancer and actively receiving chemotherapy; (2) their caregivers; and (3) oncology clinicians at Nationwide Children's Hospital. Participants completed 1:1 semi-structured interviews, which were audio-recorded, transcribed, and analyzed for thematic content regarding their perception of supportive care measures and views on OMT. Quantitative data was summarized descriptively. RESULTS: A total of 60 participants completed the interview. Participants demonstrated limited awareness of osteopathic medicine; no participant had more than "some" knowledge of OMT. After education about OMT using a brief video, all clinicians, caregivers, and 95% of patients were receptive to OMT as a supportive care option. Major themes included the following: (a) patients have uncontrolled chemotherapy side effects, (b) improved supportive care options are desired, and (c) osteopathic medicine is a favorable supportive care adjunct. CONCLUSIONS: Pediatric oncology clinicians, caregivers, and patients reported a need for better management of chemotherapy-associated side effects and an interest in utilizing OMT. These findings support further investigation into the safety, feasibility, and efficacy of implementing OMT in the pediatric oncology clinical setting.
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Cuidadores/normas , Medicina Osteopática/métodos , Cuidados Paliativos/métodos , Pacientes/estadística & datos numéricos , Médicos/normas , Niño , Femenino , Humanos , Masculino , Oncología MédicaRESUMEN
An international, multicenter registry was established to collect retrospective and prospective clinical data on patients with pyruvate kinase (PK) deficiency, the most common glycolytic defect causing congenital nonspherocytic hemolytic anemia. Medical history and laboratory and radiologic data were retrospectively collected at enrollment for 254 patients with molecularly confirmed PK deficiency. Perinatal complications were common, including anemia that required transfusions, hyperbilirubinemia, hydrops, and prematurity. Nearly all newborns were treated with phototherapy (93%), and many were treated with exchange transfusions (46%). Children age 5 years and younger were often transfused until splenectomy. Splenectomy (150 [59%] of 254 patients) was associated with a median increase in hemoglobin of 1.6 g/dL and a decreased transfusion burden in 90% of patients. Predictors of a response to splenectomy included higher presplenectomy hemoglobin (P = .007), lower indirect bilirubin (P = .005), and missense PKLR mutations (P = .0017). Postsplenectomy thrombosis was reported in 11% of patients. The most frequent complications included iron overload (48%) and gallstones (45%), but other complications such as aplastic crises, osteopenia/bone fragility, extramedullary hematopoiesis, postsplenectomy sepsis, pulmonary hypertension, and leg ulcers were not uncommon. Overall, 87 (34%) of 254 patients had both a splenectomy and cholecystectomy. In those who had a splenectomy without simultaneous cholecystectomy, 48% later required a cholecystectomy. Although the risk of complications increases with severity of anemia and a genotype-phenotype relationship was observed, complications were common in all patients with PK deficiency. Diagnostic testing for PK deficiency should be considered in patients with apparent congenital hemolytic anemia and close monitoring for iron overload, gallstones, and other complications is needed regardless of baseline hemoglobin. This trial was registered at www.clinicaltrials.gov as #NCT02053480.
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Anemia Hemolítica Congénita no Esferocítica/diagnóstico , Estudios de Asociación Genética , Piruvato Quinasa/deficiencia , Errores Innatos del Metabolismo del Piruvato/diagnóstico , Adolescente , Adulto , Anemia Hemolítica Congénita no Esferocítica/etiología , Anemia Hemolítica Congénita no Esferocítica/metabolismo , Anemia Hemolítica Congénita no Esferocítica/terapia , Transfusión Sanguínea , Niño , Preescolar , Colecistectomía/efectos adversos , Colecistectomía/métodos , Terapia Combinada , Activación Enzimática , Femenino , Genotipo , Humanos , Lactante , Recién Nacido , Masculino , Persona de Mediana Edad , Mutación , Fenotipo , Piruvato Quinasa/metabolismo , Errores Innatos del Metabolismo del Piruvato/etiología , Errores Innatos del Metabolismo del Piruvato/metabolismo , Errores Innatos del Metabolismo del Piruvato/terapia , Esplenectomía/efectos adversos , Esplenectomía/métodos , Evaluación de Síntomas , Resultado del Tratamiento , Adulto JovenRESUMEN
Immune thrombocytopenia (ITP) is an autoimmune bleeding disorder with isolated thrombocytopenia and hemorrhagic risk. While many children with ITP can be safely observed, treatments are often needed for various reasons, including to decrease bleeding, or to improve health related quality of life (HRQoL). There are a number of available second-line treatments, including rituximab, thrombopoietin-receptor agonists, oral immunosuppressive agents, and splenectomy, but data comparing treatment outcomes are lacking. ICON1 is a prospective, multi-center, observational study of 120 children starting second-line treatments for ITP designed to compare treatment outcomes including platelet count, bleeding, and HRQoL utilizing the Kids ITP Tool (KIT). While all treatments resulted in increased platelet counts, romiplostim had the most pronounced effect at 6 months (P = .04). Only patients on romiplostim and rituximab had a significant reduction in both skin-related (84% to 48%, P = .01 and 81% to 43%, P = .004) and non-skin-related bleeding symptoms (58% to 14%, P = .0001 and 54% to 17%, P = .0006) after 1 month of treatment. HRQoL significantly improved on all treatments. However, only patients treated with eltrombopag had a median improvement in KIT scores at 1 month that met the minimal important difference (MID). Bleeding, platelet count, and HRQoL improved in each treatment group, but the extent and timing of the effect varied among treatments. These results are hypothesis generating and help to improve our understanding of the effect of each treatment on specific patient outcomes. Combined with future randomized trials, these findings will help clinicians select the optimal second-line treatment for an individual child with ITP.
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Púrpura Trombocitopénica Idiopática , Calidad de Vida , Receptores Fc/administración & dosificación , Proteínas Recombinantes de Fusión/administración & dosificación , Rituximab/administración & dosificación , Trombopoyetina/administración & dosificación , Adolescente , Niño , Preescolar , Supervivencia sin Enfermedad , Femenino , Humanos , Lactante , Masculino , Recuento de Plaquetas , Estudios Prospectivos , Púrpura Trombocitopénica Idiopática/sangre , Púrpura Trombocitopénica Idiopática/tratamiento farmacológico , Tasa de Supervivencia , Factores de TiempoRESUMEN
We present here a case of MIRAGE syndrome due to novel variant (c.2318T>C) in the sterile α motif domain-containing protein 9 (SAMD9) gene. Previous reports have described the clinical phenotype, which includes myelodysplasia, recurrent infections, restriction of growth and development, adrenal insufficiency, genitourinary abnormalities, and enteropathies, often resulting in fatality within the first few years of life. This report illustrates the variability in phenotype by describing an 11-year-old male, diagnosed with MIRAGE at age 9 years when his novel variant was identified through whole exome sequencing. A brief review of previously published cases of MIRAGE syndrome and the genotypic and phenotypic spectrum are presented.
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Insuficiencia Suprarrenal/genética , Péptidos y Proteínas de Señalización Intracelular/genética , Síndromes Mielodisplásicos/genética , Niño , Humanos , Masculino , Mutación , Secuenciación del ExomaRESUMEN
Immune thrombocytopenia (ITP) is an acquired autoimmune bleeding disorder which presents with isolated thrombocytopenia and risk of hemorrhage. While most children with ITP promptly recover with or without drug therapy, ITP is persistent or chronic in others. When needed, how to select second-line therapies is not clear. ICON1, conducted within the Pediatric ITP Consortium of North America (ICON), is a prospective, observational, longitudinal cohort study of 120 children from 21 centers starting second-line treatments for ITP which examined treatment decisions. Treating physicians reported reasons for selecting therapies, ranking the top three. In a propensity weighted model, the most important factors were patient/parental preference (53%) and treatment-related factors: side effect profile (58%), long-term toxicity (54%), ease of administration (46%), possibility of remission (45%), and perceived efficacy (30%). Physician, health system, and clinical factors rarely influenced decision-making. Patient/parent preferences were selected as reasons more often in chronic ITP (85.7%) than in newly diagnosed (0%) or persistent ITP (14.3%, P = .003). Splenectomy and rituximab were chosen for the possibility of inducing long-term remission (P < .001). Oral agents, such as eltrombopag and immunosuppressants, were chosen for ease of administration and expected adherence (P < .001). Physicians chose rituximab in patients with lower expected adherence (P = .017). Treatment choice showed some physician and treatment center bias. This study illustrates the complexity and many factors involved in decision-making in selecting second-line ITP treatments, given the absence of comparative trials. It highlights shared decision-making and the need for well-conducted, comparative effectiveness studies to allow for informed discussion between patients and clinicians.
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Toma de Decisiones Clínicas , Púrpura Trombocitopénica Idiopática/tratamiento farmacológico , Niño , Toma de Decisiones , Femenino , Humanos , Inmunosupresores/uso terapéutico , Masculino , Médicos/psicología , Rituximab/uso terapéutico , EsplenectomíaRESUMEN
BACKGROUND: The thrombopoietin receptor agonist romiplostim could be an effective treatment in symptomatic children with persistent or chronic immune thrombocytopenia. We aimed to assess whether romiplostim is safe and effective in children with immune thrombocytopenia of more than 6 months' duration. METHODS: In this phase 3 double-blind study, eligible participants were children with immune thrombocytopenia aged 1 year to 17 years and mean platelet counts 30â×â10(9)/L or less (mean of two measurements during the screening period) with no single count greater than 35â×â10(9)/L, and were recruited from 27 sites in the USA, Canada, and Australia. Participants were randomly assigned (2:1) through the interactive voice response system to receive weekly romiplostim or placebo for 24 weeks stratified by age (1 year to <6 years, 6 years to <12 years, 12 years to <18 years), adjusting the dose weekly from 1 µg/kg to 10 µg/kg to target platelet counts of 50-200â×â10(9)/L. Patients and investigators were blinded to the treatment assignment. The primary analysis included all randomised patients and the safety analysis included all randomised patients who received at least one dose of investigational product. The primary endpoint, durable platelet response, was defined as achievement of weekly platelet responses (platelet counts ≥50â×â10(9)/L without rescue drug use in the preceding 4 weeks) in 6 or more of the final 8 weeks (weeks 18-25). This study is registered with ClinicalTrials.gov, NCT 01444417. FINDINGS: Between Jan 24, 2012, and Sept 3, 2014, 62 patients were randomly assigned; 42 to romiplostim and 20 to placebo. Durable platelet response was seen in 22 (52%) patients in the romiplostim group and two (10%) in the placebo group (p=0·002, odds ratio 9·1 [95% CI 1·9-43·2]). Durable platelet response rates with romiplostim by age were 38% (3/8) for 1 year to younger than 6 years, 56% (10/18) for 6 years to younger than 12 years, and 56% (9/16) for 12 years to younger than 18 years. One (5%) of 19 patients in the placebo group had serious adverse events compared with 10 (24%) of 42 patients in the romiplostim group. Of these serious adverse events, headache and thrombocytosis, in one (2%) of 42 patients in the romiplostim group, were considered treatment related. No patients withdrew due to adverse events. INTERPRETATION: In children with chronic immune thrombocytopenia, romiplostim induced a high rate of platelet response with no new safety signals. Ongoing romiplostim studies will provide further information as to long-term efficacy, safety, and remission in children with immune thrombocytopenia. FUNDING: Amgen Inc.
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Púrpura Trombocitopénica Idiopática/tratamiento farmacológico , Receptores Fc/uso terapéutico , Receptores de Trombopoyetina/agonistas , Proteínas Recombinantes de Fusión/uso terapéutico , Trombopoyetina/uso terapéutico , Adolescente , Niño , Preescolar , Método Doble Ciego , Femenino , Humanos , Lactante , Masculino , Recuento de Plaquetas , Púrpura Trombocitopénica Idiopática/sangre , Resultado del TratamientoAsunto(s)
Sobrecarga de Hierro/etiología , Sobrecarga de Hierro/metabolismo , Piruvato Quinasa/deficiencia , Biomarcadores , Transfusión Sanguínea , Análisis Mutacional de ADN , Manejo de la Enfermedad , Humanos , Hierro/metabolismo , Sobrecarga de Hierro/diagnóstico , Sobrecarga de Hierro/epidemiología , Imagen por Resonancia Magnética , Mutación , PrevalenciaRESUMEN
CAMT is a bone marrow failure syndrome that usually presents with isolated thrombocytopenia soon after birth. HSCT is curative, and MAC is associated with increased transplant-related morbidity and mortality, especially in the unrelated setting. We used a RIC regimen with alemtuzumab, fludarabine, and melphalan in a seven-month-old patient with CAMT who underwent a MUD HSCT. The transplant was well tolerated with few complications. Neutrophil and platelet engraftment occurred on day +12 and +29, respectively, and she had 100% donor chimerisms on days +19.
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Trasplante de Células Madre Hematopoyéticas , Trombocitopenia/terapia , Acondicionamiento Pretrasplante/métodos , Alemtuzumab , Anticuerpos Monoclonales Humanizados/administración & dosificación , Plaquetas/citología , Síndromes Congénitos de Insuficiencia de la Médula Ósea , Femenino , Enfermedad Veno-Oclusiva Hepática/complicaciones , Humanos , Lactante , Melfalán/administración & dosificación , Metilprednisolona/administración & dosificación , Mucositis/complicaciones , Neutrófilos/citología , Vidarabina/administración & dosificación , Vidarabina/análogos & derivadosAsunto(s)
Citometría de Flujo/métodos , Proteína del Síndrome de Wiskott-Aldrich/genética , Síndrome de Wiskott-Aldrich/diagnóstico , Síndrome de Wiskott-Aldrich/genética , Niño , Preescolar , Femenino , Humanos , Lactante , Recién Nacido , Masculino , Tamizaje Masivo/métodos , Sensibilidad y Especificidad , Proteína del Síndrome de Wiskott-Aldrich/análisisRESUMEN
CONTEXT: Pediatric patients receiving chemotherapy experience unwanted therapy-induced side effects, commonly constipation and pain that diminish quality of life. To date, few studies have investigated the safety and feasibility of osteopathic manipulative treatment (OMT) in pediatric oncology. OBJECTIVES: The primary objective of this study is to investigate the safety and feasibility of OMT in pediatric oncology outpatient clinics. METHODS: This is a single institutional pilot study evaluating children aged ≥2-21 years receiving chemotherapy for an oncological diagnosis at Nationwide Children's Hospital (NCH). Permission was obtained from the NCH Institutional Review Board. Participants were enrolled for 8 weeks and received weekly OMT. OMT was deemed feasible by participating in six out of eight weekly treatments, and safety was assessed through adverse event grading per Common Terminology Criteria for Adverse Events (CTCAE). During the clinic visit, patients answered validated surveys on constipation (Bristol Stool Scale) and pain (FACES Scale) pre/post-OMT. Feasibility was analyzed utilizing a one-sided exact binomial test while validated tools and adverse events were summarized descriptively. RESULTS: A total of 23 patients were enrolled, with 21 included in feasibility analyses. The majority of the patients were female (n=13, 61.9%), with a median age of 12 years at enrollment (range, 2.7-20.8 years). There were no serious adverse events attributed to OMT intervention, and among the patients assessed for feasibility, 100% of them participated in at least two-thirds of their weekly OMT treatments, meeting our defined feasibility criteria. The intervention lasted an average of 14.2 min (range, 7.2-19.2 min). There were no FACES or Bristol Stool Scale scores that correlated with worsening pain on constipation post-OMT intervention. CONCLUSIONS: Pediatric oncology patients were feasibly and safely able to receive OMT during a regularly scheduled chemotherapy visit. The limitations include the small sample size. These findings support the need to further investigate the safety and feasibility, as well as efficacy, of OMT in the pediatric oncology clinical setting.
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Osteopatía , Medicina Osteopática , Adolescente , Adulto , Niño , Preescolar , Estreñimiento/etiología , Estreñimiento/terapia , Estudios de Factibilidad , Femenino , Humanos , Masculino , Pacientes Ambulatorios , Dolor , Proyectos Piloto , Calidad de Vida , Adulto JovenRESUMEN
Castleman disease is a non-clonal, lymphoproliferative disorder rarely seen in children. Presented is a 12-year-old male with progressive abdominal pain, vomiting, and fever. Diagnostic testing revealed multi-organ system involvement and the diagnosis was ultimately made with tissue biopsy. Marked disease regression occurred after high-dose steroids and continued interleukin-6 inhibition.
RESUMEN
Chronic lung injury in the neonate is termed bronchopulmonary dysplasia (BPD). These patients generally require supplemental oxygen therapy, and hyperoxia has been implicated in the pathogenesis of BPD. The concomitant use of oxygen and inhaled NO (iNO) may result in the generation of reactive nitrogen species or may have an anti-inflammatory effect in the neonatal lung. We tested the hypothesis that exposure to >95% O2 in neonatal mice would increase trafficking of leukocytes into the lung and that the addition of iNO to >95% O2 would decrease this leukocyte trafficking. Hyperoxia resulted in fewer alveoli, increased presence of neutrophils and macrophages, and decreased number of mast cells within the lung parenchyma. Adding iNO to hyperoxia prevented the hyperoxia-induced changes and resulted in the numbers of alveoli, neutrophils, macrophages, and mast cells approximating those found in controls (room air exposure). Intercellular adhesion molecule (ICAM) and monocyte chemotactic protein-1 (MCP-1), two factors responsible for leukocyte recruitment, were up-regulated by hyperoxic exposure, but the addition of iNO to the hyperoxic exposure prevented the hyperoxia-induced up-regulation of ICAM and MCP-1. These data demonstrate that iNO alters the hyperoxia-induced recruitment of leukocytes into the lung.
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Quimiotaxis de Leucocito/efectos de los fármacos , Hiperoxia/inmunología , Óxido Nítrico/administración & dosificación , Alveolos Pulmonares/efectos de los fármacos , Administración por Inhalación , Animales , Animales Recién Nacidos , Quimiocina CCL2/metabolismo , Modelos Animales de Enfermedad , Hiperoxia/etiología , Hiperoxia/patología , Molécula 1 de Adhesión Intercelular/metabolismo , Macrófagos/efectos de los fármacos , Macrófagos/inmunología , Mastocitos/efectos de los fármacos , Mastocitos/inmunología , Ratones , Infiltración Neutrófila/efectos de los fármacos , Oxígeno , Alveolos Pulmonares/inmunología , Alveolos Pulmonares/patologíaRESUMEN
Inhaled nitric oxide is being evaluated as a preventative therapy for patients at risk for bronchopulmonary dysplasia (BPD). Nitric oxide (NO), in the presence of superoxide, forms peroxynitrite, which reacts with tyrosine residues on proteins to form 3-nitrotyrosine (3-NT). However, NO can also act as an antioxidant and was recently found to improve the oxidative balance in preterm infants. Thus, we tested the hypothesis that the addition of a therapeutically relevant concentration (10 ppm) of NO to a hyperoxic exposure would lead to decreased 3-NT formation in the lung. FVB mouse pups were exposed to either room air (21% O(2)) or >95% O(2) with or without 10 ppm NO within 24 h of birth. In the first set of studies, body weights and survival were monitored for 7 days, and exposure to >95% O(2) resulted in impaired weight gain and near 100% mortality by 7 days. However, the mortality occurred earlier in pups exposed to >95% O(2) + NO than in pups exposed to >95% O(2) alone. In a second set of studies, lungs were harvested at 72 h. Immunohistochemistry of the lungs at 72 h revealed that the addition of NO decreased alveolar, bronchial, and vascular 3-NT staining in pups exposed to both room air and hyperoxia. The lung nitrite levels were higher in animals exposed to >95% oxygen + NO than in animals exposed to >95% oxygen alone. The protein levels of myeloperoxidase, monocyte chemotactic protein-1, and intracellular adhesion molecule-1 were assessed after 72 h of exposure and found to be greatest in the lungs of pups exposed to >95% O(2). This hyperoxia-induced protein expression was significantly attenuated by the addition of 10 ppm NO. We propose that in the presence of >95% O(2), peroxynitrite formation results in protein nitration; however, adding excess NO to the >95% O(2) exposure prevents 3-NT formation by NO reacting with peroxynitrite to produce nitrite and NO(2). We speculate that the decreased protein nitration observed with the addition of NO may be a potential mechanism limiting hyperoxic lung injury.