RESUMO
OBJECTIVES: Iron overload in patients with thalassemia represents a serious complication by affecting numerous organ systems. This meta-analysis aims to establish an evidence regarding the effect of amlodipine on cardiac iron overload in thalassemia patients. METHODS: We searched PubMed, Scopus, Web of Science, Cochrane Central, and EMBASE for all relevant randomized controlled trials (RCTs). The primary outcomes were cardiac T2* and myocardial iron concentration (MIC). Secondary outcomes were liver iron concentration (LIC), risk of Gastrointestinal (G.I.) upset and risk of lower limb edema. We used Hedges' g to pool continuous outcomes, while odds ratio was used for dichotomous outcomes. RESULTS: Seven RCTs were eligible for this systematic review and meta-analysis, comprising of 233 patients included in the analysis. Amlodipine had a statistically significant lower MIC (Hedges' g = -0.82, 95% confidence interval [CI] [-1.40, -0.24], p < .001) and higher cardiac T2* (Hedges' g = 0.36, 95% CI [0.10, 0.62], p = .03). Amlodipine was comparable to standard chelation therapy in terms of the risk of lower limb edema and GI upset. CONCLUSION: Our meta-analysis found that amlodipine significantly increases cardiac T2* and decreases MIC, hence decreasing the incidence of cardiomyopathy-related iron overload in thalassemia patients.
Assuntos
Sobrecarga de Ferro , Siderose , Talassemia , Talassemia beta , Humanos , Bloqueadores dos Canais de Cálcio/uso terapêutico , Siderose/complicações , Siderose/tratamento farmacológico , Talassemia beta/complicações , Talassemia/terapia , Ferro , Sobrecarga de Ferro/etiologia , Anlodipino/uso terapêutico , Quelantes de Ferro/uso terapêuticoRESUMO
OBJECTIVE: Aggressive iron substitution in hemodialysis (HD) patients leads to iron overload. The association between liver siderosis and fibrosis is still debatable. We studied the association of liver siderosis with liver fibrosis in HD patients. Furthermore, we studied the performance of liver stiffness measurements (LSMs) in identifying advanced liver fibrosis. We investigated the performance of biochemical indicators of iron status in identifying advanced liver fibrosis. METHODS: Fifty-five HD patients (average HD duration 6 ± 2 years) with hyperferritinemia secondary to intravenous iron supplementation (weakly iron dose 252.7 ± 63 mg; median blood transfusions 3 [2-5]) were recruited. The liver fibrosis grade was determined with Fibroscan, aminotransferase-to-platelet ratio index (APRI), and Fib-4 index. Liver iron concentration (LIC) was estimated with magnetic resonance imaging (MRI). Iron parameters and liver function biochemical indicators were also assessed. RESULTS: The median serum ferritin and transferrin saturation (TSAT) were 3531 µg/L and 77%, respectively. 34.5%, 20%, and 45.5% of the patients showed mild, moderate, or severe liver siderosis, respectively. All patients with severe liver siderosis showed advanced liver fibrosis. Patients with severe liver siderosis and advanced liver stiffness showed higher serum iron, TSAT, aspartate aminotransferase (AST), alanine aminotransferase (ALT), serum bilirubin, APRI, and Fib-4 index scores than those with mild liver siderosis. Serum iron and TSAT showed good utility in identifying advanced liver fibrosis determined with Fibroscan, APRI, and Fib-4 index. Liver stiffness exhibited good utility in identifying advanced liver fibrosis diagnosed with APRI and Fib-4 index. CONCLUSIONS: High weekly intravenous iron dose associated with severe hyperferritinemia, high serum iron, and TSAT might lead to severe liver siderosis and concomitant liver fibrosis in HD patients. Serum iron, TSAT, Fibroscan, Fib-4, and APRI scores might offer noninvasive tools for identifying advanced liver fibrosis in those patients.
Assuntos
Hiperferritinemia , Siderose , Humanos , Ferro , Contagem de Plaquetas , Biópsia , Cirrose Hepática/complicações , Cirrose Hepática/diagnóstico , Suplementos Nutricionais , BiomarcadoresRESUMO
Objective: Cardiac T2* magnetic resonance imaging (MRI) has recently attracted considerable attention as a non-invasive method for detecting iron overload in various organs in thalassemia major patients. This study aimed to identify the prevalence of cardiac siderosis in thalassemia major patients and evaluate cardiac T2* MRI for monitoring cardiac siderosis before and after patients receive iron chelation therapy and its relation to serum ferritin, left ventricular ejection fraction, and liver iron concentration. The information gathered would be used for the direct monitoring, detection, and treatment of complications early on. Methods: A total of 119 thalassemia major patients were recruited in the present study. The cardiac T2* MRI was compared to serum ferritin levels, liver iron concentration (LIC), and left ventricular ejection fraction. All patients were classified into four groups based on their cardiac siderosis as having normal, marginal, mild to moderate, or severe cardiac iron overload. At the follow-up at years one, three, and five, the cardiac T2* MRI, LIC, serum ferritin, and left ventricular ejection fraction (LVEF) were determined. Results: The prevalence of cardiac siderosis with cardiac T2* MRI ≤ 25 ms was 17.6% (n = 21). There was no correlation between cardiac T2* MRI and serum ferritin, liver iron concentration, and LVEF (p = 0.39, 0.54, and 0.09, respectively). During one year to five years' follow-up periods, cardiac T2* MRI (ms) in patients with severe cardiac siderosis had significantly improved from 8.5 ± 1.49 at baseline to 33.9 ± 1.9 at five years (p < 0.0001). Patients with severe, mild-moderate, marginal, and no cardiac siderosis had median LIC (mg/g dw) of 23.9 ± 6.5, 21.6 ± 13.3, 25.3 ± 7.7, and 19.9 ± 5.5 at baseline, respectively. Conclusions: This study supports the use of cardiac T2* MRI to monitor cardiac iron overload in patients who have had multiple blood transfusions. Early diagnosis and treatment of patients at risk of cardiac siderosis is a reasonable method of reducing the substantial cardiac mortality burden associated with myocardial siderosis. Cardiac T2* MRI is the best test that can identify at-risk patients who can be managed with optimization of their chelation therapy.
Assuntos
Siderose , Talassemia beta , Ferritinas , Humanos , Ferro/metabolismo , Fígado/diagnóstico por imagem , Imageamento por Ressonância Magnética , Miocárdio/metabolismo , Siderose/diagnóstico por imagem , Siderose/epidemiologia , Volume Sistólico , Função Ventricular Esquerda , Talassemia beta/complicações , Talassemia beta/diagnóstico por imagem , Talassemia beta/terapiaRESUMO
Numerous problematic disorders such as vitamin D (Vit-D) deficiency subsequent to large iron loading can be developed in patients with ß-thalassemia. The study aimed to estimate Vit-D insufficiency and its risk factors in patients with ß-thalassemia. In this multicenter and observational study, all ß-thalassemia patients, who referred to 14 hospital-based thalassemia divisions or clinics in Mazandaran province, Iran were included in the study. The data belong to December 2015 until December 2019. The study population was made of transfusion dependent thalassemia (TDT) and non-transfusion-dependent thalassemia (NTDT) patients. Serum levels of 25-OHD3 have been measured by high performance liquid chromatography (HPLC) method as ng/mL. Demographic and clinical information along with some biological tests, as well as the results of T2*-weighted magnetic resonance imaging were analyzed. Of 1959 registered patients, 487 (24.9%) patients had Vit-D-related data. The prevalence of Vit-D insufficiency (< 30 ng/mL) was 41.9, 95% CI 37.5-46.3. The adjusted risks of moderate to severe liver siderosis and raised AST (aspartate aminotransferase) for Vit-D insufficiency (< 30 ng/mL) were 2.31, 95% CI 1.38-3.89 and 2.62, 95% CI 1.43-4.79, respectively. The receiver operating characteristic (ROC) curve analysis showed that the predictive accuracy of ferritin for Vit-D insufficiency status was 0.61, 95% CI 0.54-0.68 with a cutoff point of 1,078 ng/mL (P = 0.03, sensitivity 67%, specificity 49%, positive predictive value [PPV] 47% and negative predictive value [NPV] 68%). In spite of the national programs for treating Vit-D deficiency and our previous efforts for giving supplements to all patients, Vit-D insufficiency/deficiency is still common in our patients. Also, moderate to severe liver siderosis and raised AST were the independent risk factors for the Vit-D insufficiency.
Assuntos
Aspartato Aminotransferases/sangue , Fígado/patologia , Siderose/complicações , Deficiência de Vitamina D/complicações , Talassemia beta/complicações , Adulto , Transfusão de Sangue , Feminino , Humanos , Modelos Logísticos , Masculino , Análise Multivariada , Fatores de Risco , Siderose/sangue , Deficiência de Vitamina D/sangue , Talassemia beta/sangueRESUMO
Intravenous ferric carboxymaltose is increasingly used to treat iron deficiency. However, a common side-effect is paravenous extravasation of iron preparations, resulting in cutaneous siderosis. Quality-switched (QS) lasers and, recently, picosecond (PS) lasers have been used to treat these hyperpigmentations with variable success. The optimal treatment protocol remains unclear. The aims of this study were to assess the response of cutaneous siderosis to treatment with pigment lasers and to determine the optimal wavelength, number of treatment sessions and pulse duration. Fifteen patients with cutaneous siderosis on the arms were included. The effectiveness of laser treatment was evaluated using a 5-point standard Physician Global Assessment (PGA) grading system. Differences in continuous variables between distinct groups of patients were assessed with a Mann-Whitney U test. In all 15 patients clearance of at least 50% was obtained. In 12 patients, at least 75% of pigment was removed. In conclusion, pigment lasers are an effective and safe method to treat cutaneous siderosis.
Assuntos
Extravasamento de Materiais Terapêuticos e Diagnósticos/radioterapia , Compostos Férricos/efeitos adversos , Hematínicos/efeitos adversos , Doença Iatrogênica , Lasers de Estado Sólido/uso terapêutico , Terapia com Luz de Baixa Intensidade/instrumentação , Maltose/análogos & derivados , Siderose/radioterapia , Dermatopatias/radioterapia , Administração Intravenosa , Adolescente , Adulto , Idoso , Extravasamento de Materiais Terapêuticos e Diagnósticos/diagnóstico , Extravasamento de Materiais Terapêuticos e Diagnósticos/etiologia , Feminino , Compostos Férricos/administração & dosagem , Hematínicos/administração & dosagem , Humanos , Lasers de Estado Sólido/efeitos adversos , Terapia com Luz de Baixa Intensidade/efeitos adversos , Maltose/administração & dosagem , Maltose/efeitos adversos , Pessoa de Meia-Idade , Estudos Retrospectivos , Siderose/diagnóstico , Siderose/etiologia , Dermatopatias/diagnóstico , Dermatopatias/etiologia , Resultado do Tratamento , Adulto JovemAssuntos
Doenças dos Gânglios da Base/diagnóstico , Neoplasias Encefálicas/diagnóstico , Córtex Cerebral/patologia , Hemangioma Cavernoso do Sistema Nervoso Central/diagnóstico , Siderose/diagnóstico , Tálamo/patologia , Doenças dos Gânglios da Base/etiologia , Neoplasias Encefálicas/complicações , Feminino , Hemangioma Cavernoso do Sistema Nervoso Central/complicações , Humanos , Pessoa de Meia-Idade , Siderose/etiologia , SíndromeRESUMO
OBJECTIVES: Estimating the prevalence of glutathione S-transferase gene polymorphism (GSTM1) null genotype among patients with beta thalassemia major (ß-TM) in relation to myocardial status assessed by tissue Doppler and cardiac siderosis assessed by cardiac magnetic resonance imaging (MRI) T2*. METHODS: Hundred patients with ß-TM and 100 healthy controls were enrolled. Complete blood count (CBC), mean serum ferritin and GSTM1 genotyping, echocardiography, tissue Doppler, and cardiac MRI T2* were done. RESULTS: Serum ferritin ranged from 1200 to 8000 ng/ml, and mean T2* value was 27.10 ± 11.20 ms. Of patients, 68 (68%) had no cardiac siderosis, while 24 (24%) with mild to moderate, and 8 (8%) with sever cardiac siderosis. T2* values were not correlated with serum ferritin (r = -0.09, P = 0.50). GSTM1 null genotype was prevalent in 46% of patients and 40% of controls (P = 0.69). Patients with null genotype had significantly shorter T2* (P = 0.001), higher left ventricular end-diastolic diameter (P = 0.002), and shorter ejection time (P = 0.005) with no significant relation to serum ferritin (P = 0.122). GSTM1 null genotype was the only predictor for cardiac iron overload (P = 0.002). DISCUSSION: Serum ferritin concentrations have been shown to correlate poorly with all stages of cardiac dysfunction. Low cardiac MRI T2* values occur in patients with ß-TM despite good chelation therapy, suggesting a possible role of genetic factors in cardiac siderosis. CONCLUSION: GSTM1 null genotype is significantly associated with cardiac iron overload independent of serum ferritin in Egyptian patients with ß-TM.
Assuntos
Glutationa Transferase/genética , Sobrecarga de Ferro/genética , Ferro/metabolismo , Polimorfismo Genético , Siderose/genética , Talassemia beta/terapia , Adolescente , Estudos de Casos e Controles , Criança , Egito , Feminino , Ferritinas/sangue , Ferritinas/genética , Expressão Gênica , Genótipo , Glutationa Transferase/deficiência , Humanos , Sobrecarga de Ferro/etiologia , Sobrecarga de Ferro/metabolismo , Sobrecarga de Ferro/patologia , Masculino , Miocárdio/metabolismo , Miocárdio/patologia , Índice de Gravidade de Doença , Siderose/etiologia , Siderose/metabolismo , Siderose/patologia , Reação Transfusional , Talassemia beta/genética , Talassemia beta/patologiaRESUMO
Superficial siderosis is caused by recurrent haemorrhage in the subarachnoid space leading to haemosiderin deposition. It typically causes the triad of ataxia, deafness and myelopathy. We report a patient who developed superficial siderosis following neurosurgery for syringomyelia and who had an improvement in his hearing and mobility following treatment with a new iron chelation therapy that can penetrate the blood-brain barrier. It provides an intriguing insight into a therapy that could potentially modify the course of this rare neurodegenerative disorder. Further studies are required to assess the clinical efficacy of deferiprone in superficial siderosis.
Assuntos
Terapia por Quelação , Quelantes de Ferro/uso terapêutico , Ferro , Piridonas/uso terapêutico , Siderose/tratamento farmacológico , Idoso , Deferiprona , Humanos , MasculinoRESUMO
Serotonin (5-HT) has long been recognized as a neurotransmitter in the central nervous system, where it modulates a variety of behavioral functions. Availability of 5-HT depends on the expression of the enzyme tryptophan hydroxylase (TPH), and the recent discovery of a dual system for 5-HT synthesis in the brain (TPH2) and periphery (TPH1) has renewed interest in studying the potential functions played by 5-HT in nonnervous tissues. Moreover, characterization of the TPH1 knockout mouse model (TPH1(-/-)) led to the identification of unsuspected roles for peripheral 5-HT, revealing the importance of this monoamine in regulating key physiological functions outside the brain. Here, we present in vivo data showing that mice deficient in peripheral 5-HT display morphological and cellular features of ineffective erythropoiesis. The central event occurs in the bone marrow where the absence of 5-HT hampers progression of erythroid precursors expressing 5-HT(2A) and 5-HT(2B) receptors toward terminal differentiation. In addition, red blood cells from 5-HT-deficient mice are more sensitive to macrophage phagocytosis and have a shortened in vivo half-life. The combination of these two defects causes TPH1(-/-) animals to develop a phenotype of macrocytic anemia. Direct evidence for a 5-HT effect on erythroid precursors is provided by supplementation of the culture medium with 5-HT that increases the proliferative capacity of both 5-HT-deficient and normal cells. Our thorough analysis of TPH1(-/-) mice provides a unique model of morphological and functional aberrations of erythropoiesis and identifies 5-HT as a key factor for red blood cell production and survival.
Assuntos
Eritrócitos/patologia , Eritropoese , Serotonina/deficiência , Anemia Macrocítica/complicações , Anemia Macrocítica/enzimologia , Anemia Macrocítica/patologia , Animais , Medula Óssea/efeitos dos fármacos , Medula Óssea/patologia , Ciclo Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Suplementos Nutricionais , Eritrócitos/efeitos dos fármacos , Eritrócitos/enzimologia , Células Precursoras Eritroides/metabolismo , Células Precursoras Eritroides/patologia , Eritropoese/efeitos dos fármacos , Ferro/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Fenótipo , Receptores de Serotonina/metabolismo , Serotonina/farmacologia , Agonistas do Receptor de Serotonina/farmacologia , Siderose/complicações , Siderose/patologia , Baço/efeitos dos fármacos , Baço/patologia , Triptofano Hidroxilase/deficiência , Triptofano Hidroxilase/metabolismoRESUMO
The trial CICL670AUS04 was a single-arm, open-label study of the cardiac efficacy of 18 months of deferasirox monotherapy [1]. Cardiac response in this study was related to the degree of liver siderosis. Patients with mild to moderate liver siderosis improved their cardiac T2* while more severely siderotic patients did not, regardless of initial cardiac iron burden. In this letter, we report 2-year data in those patients who completed a 6-month extension phase (N 5 10). Cardiac and liver iron improved steadily during the 24-month period, with final cardiac T2* and LIC improving 37% and 27%, respectively, in this cohort. Serum ferritin and LVEF were not statistically different at anytime-point. When the extension phase (18-24 months) was considered in isolation, serum ferritin, liver iron concentration, and left ventricular ejection fraction were nearly identical to 18 month results. Despite this, cardiac T2* continued to trend higher, increasing 12.7% from 9.5 ms to 10.7 ms (P 5 0.06). Thus defersirox continued to demonstrate cardiac efficacy in patients with mild to moderate hepatic siderosis throughout 2 years of therapy.
Assuntos
Benzoatos/uso terapêutico , Cardiomiopatias/tratamento farmacológico , Terapia por Quelação , Quelantes de Ferro/uso terapêutico , Siderose/tratamento farmacológico , Triazóis/uso terapêutico , Cardiomiopatias/etiologia , Deferasirox , Ferritinas/análise , Seguimentos , Humanos , Hepatopatias/tratamento farmacológico , Hepatopatias/etiologia , Siderose/etiologia , Volume Sistólico , Reação Transfusional , Resultado do Tratamento , Talassemia beta/complicaçõesRESUMO
Cardiac involvement in patients with thalassemia intermedia (TI) is characterized by a high-output state and pulmonary hypertension, with systolic left ventricle function usually being preserved. Myocardial iron overload in patients with TI has not been extensively studied. We conducted a cross-sectional study of 49 Italian patients with TI. Patient charts were reviewed and data collected for transfusion and iron chelation history, status of the spleen, and comorbid illnesses or infections. Blood samples were obtained for assessment of hemoglobin, serum ferritin, and liver enzyme levels. Doppler echocardiography was done for all patients. Cardiac and hepatic iron levels were measured by magnetic resonance imaging T2*. The mean age was 40.5 +/- 8.3 years, with a male to female ratio of 29:20. A total of 34 (69.4%) patients were splenectomized, and four patients had evidence of hepatitis C infection. Around 45% of patients were transfusion naïve while the rest received infrequent (47%) or regular (8%) transfusions. A total of 31 (63.3%) patients were maintained on iron chelation therapy. None of the patients had evidence of heart failure. Mean serum ferritin and liver iron concentration were 1,060.2 ng/ml and 8.2 mg Fe per gram dry weight, respectively. None of the patients had evidence of cardiac iron overload (mean cardiac T2* = 38.7 +/- 11.0 ms). There were no statistically significant correlation between cardiac T2* values and liver iron concentration, serum ferritin, or any patient, disease, or treatment-related parameters. Patients with TI show absence of cardiac iron overload even if hepatic iron accumulation is significant.
Assuntos
Cardiopatias/diagnóstico por imagem , Sobrecarga de Ferro/diagnóstico por imagem , Hepatopatias/diagnóstico por imagem , Imageamento por Ressonância Magnética/métodos , Siderose/diagnóstico por imagem , Talassemia/diagnóstico por imagem , Adulto , Estudos de Coortes , Estudos Transversais , Feminino , Cardiopatias/epidemiologia , Hepatite C/complicações , Hepatite C/diagnóstico , Humanos , Sobrecarga de Ferro/complicações , Sobrecarga de Ferro/epidemiologia , Hepatopatias/complicações , Hepatopatias/epidemiologia , Masculino , Pessoa de Meia-Idade , Radiografia , Siderose/epidemiologia , Talassemia/complicações , Talassemia/epidemiologia , Adulto JovemRESUMO
Over the past few decades, Taiwan has seen striking improvements in the life expectancy of its 400 registered beta-thalassemia major (beta-TM) patients due mainly to adequate transfusion regimens and effective iron chelation therapy. Since 1995, Taiwanese citizens have enjoyed universal health care through National Health Insurance (NIH), receiving comprehensive treatment at minimal cost. In 1984, a national program for thalassemia prevention, control, and hematopoietic stem cell transplantation (HSCT) was initiated. Recent data show 1- and 2-year event-free survival rates of 85 and 78%, respectively. Chelation agents like deferoxamine (DFO), deferiprone (L1) and deferasirox (DFRA) are available in Taiwan, and therapy is tailored to individuals based on drug availability and tissue distribution of iron load. Intensive chelation regimens combining L1 and DFO are recommended in patients with cardiac complications, while DFRA has been found to be effective in reducing serum ferritin, with acceptable side effects. Here, we report advances in thalassemia treatment in Taiwan and suggest treatment guidelines.
Assuntos
Cardiomiopatias/tratamento farmacológico , Quelantes de Ferro/uso terapêutico , Siderose/tratamento farmacológico , Talassemia beta/terapia , Benzoatos/administração & dosagem , Benzoatos/uso terapêutico , Transfusão de Sangue , Transplante de Medula Óssea , Terapia por Quelação , Ensaios Clínicos como Assunto , Terapia Combinada , Deferasirox , Deferiprona , Desferroxamina/administração & dosagem , Desferroxamina/uso terapêutico , Ferritinas/sangue , Guias como Assunto , Transplante de Células-Tronco Hematopoéticas , Humanos , Quelantes de Ferro/administração & dosagem , Piridonas/administração & dosagem , Piridonas/uso terapêutico , Sideróforos/administração & dosagem , Sideróforos/uso terapêutico , Taiwan , Resultado do Tratamento , Triazóis/administração & dosagem , Triazóis/uso terapêutico , Talassemia beta/tratamento farmacológico , Talassemia beta/cirurgiaRESUMO
BACKGROUND: In thalassemia major (TM), severe cardiac siderosis can be treated by continuous parenteral deferoxamine, but poor compliance, complications and deaths occur. Combined chelation therapy with deferiprone and deferoxamine is effective for moderate myocardial siderosis, but has not been prospectively examined in severe myocardial siderosis. METHODS: T2* cardiovascular magnetic resonance (CMR) was performed in 167 TM patients receiving standard subcutaneous deferoxamine monotherapy, and 22 had severe myocardial siderosis (T2* < 8 ms) with impaired left ventricular (LV) function. Fifteen of these patients received combination therapy with subcutaneous deferoxamine and oral deferiprone with CMR follow-up. RESULTS: At baseline, deferoxamine was prescribed at 38 +/- 10.2 mg/kg for 5.3 days/week, and deferiprone at 73.9 +/- 4.0 mg/kg/day. All patients continued both deferiprone and deferoxamine for 12 months. There were no deaths or new cardiovascular complications. The myocardial T2* improved (5.7 +/- 0.98 ms to 7.9 +/- 2.47 ms; p = 0.010), with concomitant improvement in LV ejection fraction (51.2 +/- 10.9% to 65.6 +/- 6.7%; p < 0.001). Serum ferritin improved from 2057 (CV 7.6%) to 666 (CV 13.2%) microg/L (p < 0.001), and liver iron improved (liver T2*: 3.7 +/- 2.9 ms to 10.8 +/- 7.3 ms; p = 0.006). CONCLUSION: In patients with severe myocardial siderosis and impaired LV function, combined chelation therapy with subcutaneous deferoxamine and oral deferiprone reduces myocardial iron and improves cardiac function. This treatment is considerably less onerous for the patient than conventional high dose continuous subcutaneous or intravenous deferoxamine monotherapy, and may be considered as an alternative. Very prolonged tailored treatment with iron chelation is necessary to clear myocardial iron, and alterations in chelation must be guided by repeated myocardial T2* scans. TRIAL REGISTRATION: This trial is registered as NCT00103753.
Assuntos
Cardiomiopatias/etiologia , Desferroxamina/uso terapêutico , Quelantes de Ferro/uso terapêutico , Piridonas/uso terapêutico , Siderose/etiologia , Disfunção Ventricular Esquerda/etiologia , Talassemia beta/tratamento farmacológico , Administração Oral , Adulto , Cardiomiopatias/complicações , Cardiomiopatias/tratamento farmacológico , Cardiomiopatias/metabolismo , Cardiomiopatias/patologia , Cardiomiopatias/fisiopatologia , Deferiprona , Desferroxamina/administração & dosagem , Desferroxamina/efeitos adversos , Quimioterapia Combinada , Feminino , Ferritinas/sangue , Humanos , Injeções Subcutâneas , Ferro/metabolismo , Quelantes de Ferro/administração & dosagem , Quelantes de Ferro/efeitos adversos , Itália , Fígado/efeitos dos fármacos , Fígado/metabolismo , Imageamento por Ressonância Magnética , Masculino , Miocárdio/metabolismo , Peptídeo Natriurético Encefálico/sangue , Estudos Prospectivos , Piridonas/administração & dosagem , Piridonas/efeitos adversos , Índice de Gravidade de Doença , Siderose/complicações , Siderose/tratamento farmacológico , Siderose/metabolismo , Siderose/patologia , Siderose/fisiopatologia , Volume Sistólico/efeitos dos fármacos , Resultado do Tratamento , Disfunção Ventricular Esquerda/tratamento farmacológico , Disfunção Ventricular Esquerda/metabolismo , Disfunção Ventricular Esquerda/fisiopatologia , Talassemia beta/complicações , Talassemia beta/metabolismo , Talassemia beta/patologia , Talassemia beta/fisiopatologiaRESUMO
The mystery surrounding the apparent lack of iron within the macrophages of individuals with hereditary hemochromatosis, a condition of excessive uptake of dietary iron, has yet to be fully explained. We have suggested that iron deficiency of macrophages in people with hereditary hemochromatosis mutations is associated with increased resistance to infection by Yersinia and other intracellular pathogens, a selection pressure resulting in unusually high current population frequencies of hereditary hemochromatosis mutations. Such selection pressure has been called Epidemic Pathogenic Selection (EPS). In support of the theory of EPS, a considerable number of virulent species of bacteria multiply mainly in iron-rich macrophages of their mammalian hosts. Among these fastidious pathogens are strains of Chlamydia, Coxiella, Francisella, Legionella, Mycobacterium, Salmonella and Yersinia. Iron deficiency of macrophages of persons with hereditary hemochromatosis gene mutations may result in increased resistance to members of these bacterial pathogens. People with genes that result in hereditary hemochromatosis may be protected against coronary artery disease associated with Chlamydia and Coxiella infection in the absence of iron overload. In the clinical setting, when a patient appears to be iron deficient, the reason for this should be carefully evaluated. Iron supplementation may adversely affect the health of individuals who have mounted an acute phase response to infection, injury or stress, or who carry genes predisposing them to iron overload disorders.
Assuntos
Infecções Bacterianas/metabolismo , Hemocromatose/metabolismo , Ferro/metabolismo , Infecções Bacterianas/mortalidade , Doença das Coronárias/metabolismo , Doença das Coronárias/microbiologia , Hemocromatose/genética , Humanos , Macrófagos/metabolismo , Siderose/genética , Siderose/metabolismoAssuntos
Ferro da Dieta/administração & dosagem , Política Nutricional , Suplementos Nutricionais , Feminino , Alimentos Fortificados , Hemocromatose/genética , Humanos , Ferro da Dieta/efeitos adversos , Masculino , Infarto do Miocárdio/etiologia , Infarto do Miocárdio/genética , Siderose/etiologia , Estados UnidosRESUMO
To investigate the applicability of noninvasive Superconducting Quantum Interference Device (SQUID) biomagnetic liver susceptometry and its limitations in thalassemic children, 23 patients with beta-thalassemia major and other iron loading anemias (age: 4-16 years) and 16 age-related normal children were studied. Liver iron concentrations ranged from 600 to 11,000 microg/g(liver) for thalassemic patients and from 60 to 340 microg/g(liver) for normal patients. Measuring the respective organ volumes by sonography, liver and spleen iron stores, accounting for 80% of total body iron stores, were estimated. Nonliver contributions from the lung or intestine to the measured SQUID signals in the small-sized patients were not observed. Moreover, livers in thalassemia were found to be enlarged by 18% per 1,000 microg/g (r = 0.75, P < 10(-3)). Serum ferritin values correlate significantly with iron stores (r = 0.64, P < 10(-3)), but predict iron stores only within large error intervals of 4,000 microg/g(liver). Analyzing the experimental data from biomagnetometry and from related transfusion and chelation treatment data within the framework of a two-compartment model, we were able to derive additional information on total body iron elimination and chelation therapy efficacy. The exponential decline of iron stores allows forecast of steady-state conditions of the final iron load for a particular transfusion and chelation therapy regimen.
Assuntos
Ferro/análise , Fígado/química , Magnetismo , Siderose/metabolismo , Reação Transfusional , Talassemia beta/terapia , Adolescente , Adulto , Animais , Criança , Pré-Escolar , Ferritinas/sangue , Humanos , Intestinos/química , Pulmão/química , Siderose/etiologia , Baço/químicaRESUMO
Superficial siderosis of the central nervous system (SS) is a rare neurological disorder characterized by symptoms such as neurosensory hearing loss, ataxic gait, and spastic paraparesis. Recently, magnetic resonance imaging (MRI) enables us to make a clinical diagnosis. However, the exact pathophysiological mechanism underlying this disorder remains uncertain. Although iron chelation therapy has been attempted experimentally, it has not been successful and there is no effective medical treatment available. Towards the better understanding of the pathophysiological mechanism underlying SS, we performed electrophysiological studies, in which multiple evoked potential studies were included, in 3 patients with SS. Somatosensory evoked potentials (SEPs) evoked by median nerve stimulation were all normal, but those evoked by the posterior tibial nerve stimulation showed a significant delay of the latency of P40. In the auditory brainstem response (ABR) studies, there were no reproducible responses of the brainstem origin. In the blink reflex studies, R2 latency was delayed in one patient. In visual evoked potential (VEP) studies, the latency of P100 was delayed in two of three patients, unless all the patients clinically showed no visual symptom. The nerve conduction velocity studies performed in peripheral nerves of upper and lower extremities were all normal. The abnormal findings of ABR and SEP may suggest that the acoustic nerve and the posterior funiculus of the spinal cord are involved, respectively. These findings are also in a good agreement with pathological findings of SS reported in the literature. In SS, the hemosiderine accumulation is usually less severe in the visual tract; however, the delay of VEPs may suggest the latent dysfunctioning of the visual system in SS. It is suggested that multiple evoked potential study is useful for clinical evaluation of SS.
Assuntos
Encefalopatias/fisiopatologia , Siderose/fisiopatologia , Idoso , Piscadela , Potenciais Evocados Auditivos do Tronco Encefálico , Potenciais Somatossensoriais Evocados , Potenciais Evocados Visuais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Condução NervosaRESUMO
Neonatal intrahepatic cholestasis is a heterogeneous disease of undetermined cause. There is an unreported subset of idiopathic neonatal intrahepatic cholestasis with an unusual histological combination of hepatic siderosis and macrovesicular steatosis. The patients were a 34-day-old female and a 39-day-old male with normal birth weights. Their mothers had received oral iron supplement 4-6 weeks before delivery. The patients had obstructive jaundice noticed at the well-baby clinic at 1 month of life. They had high levels of serum galactose and tyrosine, hyperferritinemia. Urinary organic acid and bile acid analyses were negative, and galactose-1-phosphate uridyltransferase activity in red cells was normal. Liver biopsies showed diffuse iron deposits and macrovesicular fat. By substituting formula milk with lactose-free milk, the patients responded, and had normal biochemical tests within 5 months of life. Follow-up biopsies, at the age of 12 months, showed mild residual fibrosis without iron or fat deposits. They are both well at 3 and 6 years of age, respectively, without biochemical liver dysfunction and neurologic impairment. Prenatal iron-overload might contribute to the pathogenesis of the disease, but further studies are needed to confirm the assumption.