RESUMO
Acute lung injury, referred to as the acute chest syndrome, is a major cause of morbidity and mortality in patients with sickle cell disease (SCD), which often occurs in the setting of a vaso-occlusive painful crisis. P-selectin antibody therapy reduces hospitalization of patients with SCD by â¼50%, suggesting that an unknown P-selectin-independent mechanism promotes remaining vaso-occlusive events. In patients with SCD, intraerythrocytic polymerization of mutant hemoglobin promotes ischemia-reperfusion injury and hemolysis, which leads to the development of sterile inflammation. Using intravital microscopy in transgenic, humanized mice with SCD and in vitro studies with blood from patients with SCD, we reveal for the first time that the sterile inflammatory milieu in SCD promotes caspase-4/11-dependent activation of neutrophil-gasdermin D (GSDMD), which triggers P-selectin-independent shedding of neutrophil extracellular traps (NETs) in the liver. Remarkably, these NETs travel intravascularly from liver to lung, where they promote neutrophil-platelet aggregation and the development of acute lung injury. This study introduces a novel paradigm that liver-to-lung embolic translocation of NETs promotes pulmonary vascular vaso-occlusion and identifies a new GSDMD-mediated, P-selectin-independent mechanism of lung injury in SCD.
Assuntos
Lesão Pulmonar Aguda , Anemia Falciforme , Armadilhas Extracelulares , Proteínas de Ligação a Fosfato , Proteínas Citotóxicas Formadoras de Poros , Traumatismo por Reperfusão , Lesão Pulmonar Aguda/etiologia , Animais , Fígado , Pulmão/irrigação sanguínea , Camundongos , Camundongos Transgênicos , Selectina-P , Proteínas de Ligação a Fosfato/metabolismo , Proteínas Citotóxicas Formadoras de Poros/metabolismo , Traumatismo por Reperfusão/complicaçõesRESUMO
BACKGROUND AND AIMS: Hepatic crisis is an emergent complication affecting patients with sickle cell disease (SCD); however, the molecular mechanism of sickle cell hepatobiliary injury remains poorly understood. Using the knock-in humanized mouse model of SCD and SCD patient blood, we sought to mechanistically characterize SCD-associated hepato-pathophysiology applying our recently developed quantitative liver intravital imaging, RNA sequence analysis, and biochemical approaches. APPROACH AND RESULTS: SCD mice manifested sinusoidal ischemia, progressive hepatomegaly, liver injury, hyperbilirubinemia, and increased ductular reaction under basal conditions. Nuclear factor kappa B (NF-κB) activation in the liver of SCD mice inhibited farnesoid X receptor (FXR) signaling and its downstream targets, leading to loss of canalicular bile transport and altered bile acid pool. Intravital imaging revealed impaired bile secretion into the bile canaliculi, which was secondary to loss of canalicular bile transport and bile acid metabolism, leading to intrahepatic bile accumulation in SCD mouse liver. Blocking NF-κB activation rescued FXR signaling and partially ameliorated liver injury and sinusoidal ischemia in SCD mice. CONCLUSIONS: These findings identify that NF-κB/FXR-dependent impaired bile secretion promotes intrahepatic bile accumulation, which contributes to hepatobiliary injury of SCD. Improved understanding of these processes could potentially benefit the development of therapies to treat sickle cell hepatic crisis.
Assuntos
Anemia Falciforme/complicações , Bile/metabolismo , Colestase/etiologia , Insuficiência Hepática/etiologia , Fígado/patologia , Adolescente , Adulto , Anemia Falciforme/sangue , Anemia Falciforme/tratamento farmacológico , Anemia Falciforme/genética , Animais , Ductos Biliares Intra-Hepáticos/diagnóstico por imagem , Ductos Biliares Intra-Hepáticos/patologia , Colestase/patologia , Colestase/prevenção & controle , Modelos Animais de Doenças , Feminino , Técnicas de Introdução de Genes , Hemoglobina Falciforme/genética , Insuficiência Hepática/patologia , Insuficiência Hepática/prevenção & controle , Humanos , Microscopia Intravital , Fígado/diagnóstico por imagem , Masculino , Camundongos , Pessoa de Meia-Idade , NF-kappa B/antagonistas & inibidores , NF-kappa B/efeitos dos fármacos , NF-kappa B/metabolismo , Receptores Citoplasmáticos e Nucleares/metabolismo , Transdução de Sinais/efeitos dos fármacos , Adulto JovemRESUMO
Iron chelation therapy can prevent iron overload for pediatric patients with sickle cell disease and ß-thalassemia major; however, adherence is suboptimal. Therefore, we developed an intensive training program (ITP), to improve medication management and disease knowledge. The objectives were to determine feasibility of the ITP and its preliminary impact on adherence, disease knowledge, and health outcomes. Pediatric patients were recruited to participate in the ITP over a 90-day period and were followed for 6 months. The ITP consisted of 3 components: (1) provider-led education modules; (2) patient recording daily videos of at-home medication administration; and (3) provider feedback through video messages through the ITP app. Eleven patients participated (mean=12.4 y). Initially, patients endorsed high satisfaction and ease of use and tracked their medication usage 81% (24 out of 30) of days. At 90 days, adherence rates remained consistent (80%) and disease knowledge retention was high (96%). At 6 months, participants exhibited a clinically relevant decrease in serum ferritin, which trended toward statistical significance (P=0.068). Medication possession ratio did not significantly increase (0.65 to 0.72; not significant). The mobile ITP was feasibly implemented in a clinical setting; in addition, high levels of compliance, disease knowledge retention, and acceptance encourage larger studies evaluating mobile health technology to improve child health parameters.