Assuntos
Anemia Falciforme/enzimologia , Eritrócitos Anormais/enzimologia , Terapia de Alvo Molecular , Piperazinas/farmacologia , Piruvato Quinase/deficiência , Quinolinas/farmacologia , 2,3-Difosfoglicerato/sangue , Adolescente , Adulto , Anemia Falciforme/sangue , Anemia Falciforme/tratamento farmacológico , Forma Celular/efeitos dos fármacos , Criança , Pré-Escolar , Eritrócitos Anormais/efeitos dos fármacos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Piperazinas/uso terapêutico , Estabilidade Proteica , Piruvato Quinase/sangue , Piruvato Quinase/química , Quinolinas/uso terapêutico , Adulto JovemRESUMO
Pyruvate kinase (PK) deficiency is a rare hereditary disorder affecting red cell (RBC) glycolysis, causing changes in metabolism including a deficiency in ATP. This affects red cell homeostasis, promoting premature removal of RBCs from the circulation. In this study we characterized and evaluated the effect of AG-348, an allosteric activator of PK that is currently in clinical trials for treatment of PK deficiency, on RBCs and erythroid precursors from PK-deficient patients. In 15 patients ex vivo treatment with AG-348 resulted in increased enzymatic activity in all patient cells after 24 hours (mean increase 1.8-fold, range 1.2-3.4). ATP levels increased (mean increase 1.5-fold, range 1.0-2.2) similar to control cells (mean increase 1.6-fold, range, 1.4-1.8). Generally, PK thermostability was strongly reduced in PK-deficient RBCs. Ex vivo treatment with AG-348 increased residual activity 1.4 to >10-fold than residual activity of vehicle-treated samples. Protein analyses suggests that a sufficient level of PK protein is required for cells to respond to AG-348 treatment ex-vivo, as treatment effects were minimal in patient cells with very low or undetectable levels of PK-R. In half of the patients, ex vivo treatment with AG-348 was associated with an increase in RBC deformability. These data support the hypothesis that drug intervention with AG-348 effectively upregulates PK enzymatic activity and increases stability in PK-deficient RBCs over a broad range of PKLR genotypes. The concomitant increase in ATP levels suggests that glycolytic pathway activity may be restored. AG-348 treatment may represent an attractive way to correct the underlying pathologies of PK deficiency. (AG-348 is currently in clinical trials for the treatment of PK deficiency. ClinicalTrials.gov: NCT02476916, NCT03853798, NCT03548220, NCT03559699).
Assuntos
Eritrócitos , Piruvato Quinase , Trifosfato de Adenosina , Eritrócitos/metabolismo , Genótipo , Humanos , Piperazinas , Estabilidade Proteica , Piruvato Quinase/genética , QuinolinasRESUMO
Recently, erythropoietin (EPO) was identified as regulator of fibroblast growth factor 23 (FGF23). Proteolytic cleavage of biologically active intact FGF23 (iFGF23) results in the formation of C-terminal fragments (cFGF23). An increase in cFGF23 relative to iFGF23 suppresses FGF receptor signaling by competitive inhibition. EPO lowers the i:cFGF23 ratio, thereby overcoming iFGF23-mediated suppression of erythropoiesis. We investigated EPO-FGF23 signaling and levels of erythroferrone (ERFE) in 90 patients with hereditary hemolytic anemia (www.trialregister.nl [NL5189]). We show, for the first time, the importance of EPO-FGF23 signaling in hereditary hemolytic anemia: there was a clear correlation between total FGF23 and EPO levels (r = +0.64; 95% confidence interval [CI], 0.09-0.89), which persisted after adjustment for iron load, inflammation, and kidney function. There was no correlation between iFGF23 and EPO. Data are consistent with a low i:cFGF23 ratio. Therefore, as expected, we report a correlation between EPO and ERFE in a diverse set of hereditary hemolytic anemias (r = +0.47; 95% CI, 0.14-0.69). There was no association between ERFE and total FGF23 or iFGF23, which suggests that ERFE does not contribute to the connection between FGF23 and EPO. These findings open a new area of research and might provide potentially new druggable targets with the opportunity to ameliorate ineffective erythropoiesis and the development of disease complications in hereditary hemolytic anemias.
Assuntos
Anemia Hemolítica Congênita , Eritropoetina , Fator de Crescimento de Fibroblastos 23 , Fatores de Crescimento de Fibroblastos , Humanos , Ferro , Hormônios PeptídicosAssuntos
Anemia Hemolítica Congênita/metabolismo , Anemia Hemolítica Congênita/patologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Anemia Hemolítica Congênita/genética , Anemia Hemolítica Congênita/terapia , Estudos Transversais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Especificidade de ÓrgãosAssuntos
Sobrecarga de Ferro/etiologia , Sobrecarga de Ferro/metabolismo , Piruvato Quinase/deficiência , Biomarcadores , Transfusão de Sangue , Análise Mutacional de DNA , Gerenciamento Clínico , Humanos , Ferro/metabolismo , Sobrecarga de Ferro/diagnóstico , Sobrecarga de Ferro/epidemiologia , Imageamento por Ressonância Magnética , Mutação , PrevalênciaAssuntos
Anemia Hemolítica Congênita/complicações , Sobrecarga de Ferro/etiologia , Adulto , Estudos Transversais , Feminino , Ferritinas/sangue , Humanos , Sobrecarga de Ferro/diagnóstico , Sobrecarga de Ferro/diagnóstico por imagem , Sobrecarga de Ferro/patologia , Hepatopatias/diagnóstico , Hepatopatias/diagnóstico por imagem , Imageamento por Ressonância Magnética , Masculino , Programas de Rastreamento , Pessoa de Meia-Idade , Transferrina/metabolismoAssuntos
Anemia Hemolítica Congênita não Esferocítica/terapia , Transplante de Células-Tronco Hematopoéticas/métodos , Piruvato Quinase/deficiência , Erros Inatos do Metabolismo dos Piruvatos/terapia , Adolescente , Adulto , Anemia Hemolítica/etiologia , Anemia Hemolítica Congênita não Esferocítica/complicações , Anemia Hemolítica Congênita não Esferocítica/epidemiologia , Anemia Hemolítica Congênita não Esferocítica/mortalidade , Criança , Pré-Escolar , Transfusão de Eritrócitos , Feminino , Seguimentos , Doença Enxerto-Hospedeiro/etiologia , Transplante de Células-Tronco Hematopoéticas/efeitos adversos , Transplante de Células-Tronco Hematopoéticas/mortalidade , Humanos , Masculino , Erros Inatos do Metabolismo dos Piruvatos/complicações , Erros Inatos do Metabolismo dos Piruvatos/epidemiologia , Erros Inatos do Metabolismo dos Piruvatos/mortalidade , Estudos Retrospectivos , Análise de Sobrevida , Adulto JovemRESUMO
CONTEXT: Vitamin D insufficiency [serum 25-hydroxyvitamin D (25OHD) concentration less than 20 ng/ml] is prevalent among children with inflammatory bowel disease (IBD), and its treatment has not been studied. OBJECTIVE: The aim of this study was to compare the efficacy and safety of three vitamin D repletion regimens. DESIGN AND SETTING: We conducted a randomized, controlled clinical trial from November 2007 to June 2010 at the Clinical and Translational Study Unit of Children's Hospital Boston. The study was not blinded to participants and investigators. PATIENTS: Eligibility criteria included diagnosis of IBD, age 5-21, and serum 25OHD concentration below 20 ng/ml. Seventy-one patients enrolled, 61 completed the trial, and two withdrew due to adverse events. INTERVENTION: Patients received orally for 6 wk: vitamin D(2), 2,000 IU daily (arm A, control); vitamin D(3), 2,000 IU daily (arm B); vitamin D(2), 50,000 IU weekly (arm C); and an age-appropriate calcium supplement. MAIN OUTCOME MEASURE: We measured the change in serum 25OHD concentration (Δ25OHD) (ng/ml). Secondary outcomes included change in serum intact PTH concentration (ΔPTH) (pg/ml) and the adverse event occurrence rate. RESULTS: After 6 wk, Δ25OHD ± se was: 9.3 ± 1.8 (arm A); 16.4 ± 2.0 (arm B); 25.4 ± 2.5 (arm C); P (A vs. C) = 0.0004; P (A vs. B) = 0.03. ΔPTH ± SE was -5.6 ± 5.5 (arm A); -0.1 ± 4.2 (arm B); -4.4 ± 3.9 (arm C); P = 0.57. No participant experienced hypercalcemia or hyperphosphatemia, and the prevalence of hypercalciuria did not differ among arms at follow-up. CONCLUSIONS: Oral doses of 2,000 IU vitamin D(3) daily and 50,000 IU vitamin D(2) weekly for 6 wk are superior to 2,000 IU vitamin D(2) daily for 6 wk in raising serum 25OHD concentration and are well-tolerated among children and adolescents with IBD. The change in serum PTH concentration did not differ among arms.