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1.
Br J Haematol ; 204(5): 2016-2024, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38500389

RESUMEN

BACKGROUND: Despite numerous studies, the true scenario of hearing loss in beta-thalassaemia remains rather nebulous. MATERIALS AND METHODS: Pure tone audiometry, chelation therapy, demographics and laboratory data of 376 patients (mean age 38.5 ± 16.6 years, 204 females, 66 non-transfusion-dependent) and 139 healthy controls (mean age 37.6 ± 17.7 years, 81 females) were collected. RESULTS: Patient and control groups did not differ for age (p = 0.59) or sex (p = 0.44). Hypoacusis rate was higher in patients (26.6% vs. 7.2%; p < 0.00001), correlated with male sex (32.6% in males vs. 21.8% in females; p = 0.01) and it was sensorineural in 79/100. Hypoacusis rate correlated with increasing age (p = 0.0006) but not with phenotype (13/66 non-transfusion-dependent vs. 87/310 transfusion-dependent patients; p = 0.16). Sensorineural-notch prevalence rate did not differ between patients (11.4%) and controls (12.2%); it correlated with age (p = 0.01) but not with patients' sex or phenotype. Among adult patients without chelation therapy, the sensorineural hypoacusis rate was non-significantly lower compared to chelation-treated patients while it was significantly higher compared to controls (p = 0.003). CONCLUSIONS: Sensorineural hypoacusis rate is high in beta-thalassaemia (about 21%) and it increases with age and in males while disease severity or chelation treatment seems to be less relevant. The meaning of sensorineural-notch in beta-thalassaemia appears questionable.


Asunto(s)
Talasemia beta , Humanos , Talasemia beta/complicaciones , Talasemia beta/terapia , Masculino , Femenino , Adulto , Estudios de Casos y Controles , Persona de Mediana Edad , Italia/epidemiología , Adulto Joven , Terapia por Quelación , Pérdida Auditiva/epidemiología , Pérdida Auditiva/etiología , Adolescente , Audiometría de Tonos Puros , Pérdida Auditiva Sensorineural/epidemiología , Pérdida Auditiva Sensorineural/etiología , Prevalencia
2.
J Cell Mol Med ; 26(9): 2520-2528, 2022 05.
Artículo en Inglés | MEDLINE | ID: mdl-35355397

RESUMEN

Although numerous patient-specific co-factors have been shown to be associated with worse outcomes in COVID-19, the prognostic value of thalassaemic syndromes in COVID-19 patients remains poorly understood. We studied the outcomes of 137 COVID-19 patients with a history of transfusion-dependent thalassaemia (TDT) and transfusion independent thalassaemia (TIT) extracted from a large international cohort and compared them with the outcomes from a matched cohort of COVID-19 patients with no history of thalassaemia. The mean age of thalassaemia patients included in our study was 41 ± 16 years (48.9% male). Almost 81% of these patients suffered from TDT requiring blood transfusions on a regular basis. 38.7% of patients were blood group O. Cardiac iron overload was documented in 6.8% of study patients, whereas liver iron overload was documented in 35% of study patients. 40% of thalassaemia patients had a history of splenectomy. 27.7% of study patients required hospitalization due to COVID-19 infection. Amongst the hospitalized patients, one patient died (0.7%) and one patient required intubation. Continuous positive airway pressure (CPAP) was required in almost 5% of study patients. After adjustment for age-, sex- and other known risk factors (cardiac disease, kidney disease and pulmonary disease), the rate of in-hospital complications (supplemental oxygen use, admission to an intensive care unit for CPAP therapy or intubation) and all-cause mortality was significantly lower in the thalassaemia group compared to the matched cohort with no history of thalassaemia. Amongst thalassaemia patients in general, the TIT group exhibited a higher rate of hospitalization compared to the TDT group (p = 0.001). In addition, the rate of complications such as acute kidney injury and need for supplemental oxygen was significantly higher in the TIT group compared to the TDT group. In the multivariable logistic regression analysis, age and history of heart or kidney disease were all found to be independent risk factors for increased in-hospital, all-cause mortality, whereas the presence of thalassaemia (either TDT or TIT) was found to be independently associated with reduced all-cause mortality. The presence of thalassaemia in COVID-19 patients was independently associated with lower in-hospital, all-cause mortality and few in-hospital complications in our study. The pathophysiology of this is unclear and needs to be studied in vitro and in animal models.


Asunto(s)
COVID-19 , Sobrecarga de Hierro , Talasemia , COVID-19/complicaciones , Femenino , Hospitales , Humanos , Sobrecarga de Hierro/etiología , Masculino , Oxígeno , Sistema de Registros , Talasemia/complicaciones , Talasemia/terapia
3.
Haematologica ; 107(2): 467-477, 2022 02 01.
Artículo en Inglés | MEDLINE | ID: mdl-33406815

RESUMEN

Transfusion-dependent patients typically develop iron-induced cardiomyopathy, liver disease, and endocrine complications. We aimed to estimate the incidence of endocrine disorders in transfusiondependent thalassemia (TDT) patients during long-term iron-chelation therapy with deferasirox (DFX). We developed a multi-center follow-up study of 426 TDT patients treated with once-daily DFX for a median duration of 8 years, up to 18.5 years. At baseline, 118, 121, and 187 patients had 0, 1, or ≥2 endocrine diseases respectively. 104 additional endocrine diseases were developed during the follow-up. The overall risk of developing a new endocrine complication within 5 years was 9.7% (95% Confidence Interval [CI]: 6.3-13.1). Multiple Cox regression analysis identified three key predictors: age showed a positive log-linear effect (adjusted hazard ratio [HR] for 50% increase 1.2, 95% CI: 1.1-1.3, P=0.005), the serum concentration of thyrotropin showed a positive linear effect (adjusted HR for 1 mIU/L increase 1.3, 95% CI: 1.1-1.4, P<0.001) regardless the kind of disease incident, while the number of previous endocrine diseases showed a negative linear effect: the higher the number of diseases at baseline the lower the chance of developing further diseasess (adjusted HR for unit increase 0.5, 95% CI: 0.4-0.7, P<0.001). Age and thyrotropin had similar effect sizes across the categories of baseline diseases. The administration of levothyroxine as a covariate did not change the estimates. Although in DFX-treated TDT patients the risk of developing an endocrine complication is generally lower than the previously reported risk, there is considerable risk variation and the burden of these complications remains high. We developed a simple risk score chart enabling clinicians to estimate their patients' risk. Future research will look at increasing the amount of variation explained from our model and testing further clinical and laboratory predictors, including the assessment of direct endocrine magnetic resonance imaging.


Asunto(s)
Sobrecarga de Hierro , Talasemia , Talasemia beta , Benzoatos/efectos adversos , Terapia por Quelación/efectos adversos , Deferasirox/efectos adversos , Estudios de Seguimiento , Humanos , Quelantes del Hierro/efectos adversos , Sobrecarga de Hierro/tratamiento farmacológico , Sobrecarga de Hierro/epidemiología , Sobrecarga de Hierro/etiología , Medición de Riesgo , Factores de Riesgo , Talasemia/complicaciones , Talasemia/epidemiología , Talasemia/terapia , Triazoles/efectos adversos , Talasemia beta/complicaciones
4.
Orphanet J Rare Dis ; 16(1): 349, 2021 08 05.
Artículo en Inglés | MEDLINE | ID: mdl-34353346

RESUMEN

BACKGROUND: Sensorineural hearing loss in beta-thalassemia is common and it is generally associated with iron chelation therapy. However, data are scarce, especially on adult populations, and a possible involvement of the central auditory areas has not been investigated yet. We performed a multicenter cross-sectional audiological and single-center 3Tesla brain perfusion MRI study enrolling 77 transfusion-dependent/non transfusion-dependent adult patients and 56 healthy controls. Pure tone audiometry, demographics, clinical/laboratory and cognitive functioning data were recorded. RESULTS: Half of patients (52%) presented with high-frequency hearing deficit, with overt hypoacusia (Pure Tone Average (PTA) > 25 dB) in 35%, irrespective of iron chelation or clinical phenotype. Bilateral voxel clusters of significant relative hypoperfusion were found in the auditory cortex of beta-thalassemia patients, regardless of clinical phenotype. In controls and transfusion-dependent (but not in non-transfusion-dependent) patients, the relative auditory cortex perfusion values increased linearly with age (p < 0.04). Relative auditory cortex perfusion values showed a significant U-shaped correlation with PTA values among hearing loss patients, and a linear correlation with the full scale intelligence quotient (right side p = 0.01, left side p = 0.02) with its domain related to communication skills (right side p = 0.04, left side p = 0.07) in controls but not in beta-thalassemia patients. Audiometric test results did not correlate to cognitive test scores in any subgroup. CONCLUSIONS: In conclusion, primary auditory cortex perfusion changes are a metabolic hallmark of adult beta-thalassemia, thus suggesting complex remodeling of the hearing function, that occurs regardless of chelation therapy and before clinically manifest hearing loss. The cognitive impact of perfusion changes is intriguing but requires further investigations.


Asunto(s)
Corteza Auditiva , Pérdida Auditiva Sensorineural , Talasemia beta , Audiometría de Tonos Puros , Estudios Transversales , Pérdida Auditiva Sensorineural/etiología , Humanos
5.
Health Qual Life Outcomes ; 16(1): 216, 2018 Nov 19.
Artículo en Inglés | MEDLINE | ID: mdl-30453981

RESUMEN

BACKGROUND: Adherence to long-term chelation therapy in transfusion-dependent patients is critical to prevent iron overload-related complications. Once-daily deferasirox dispersible tablets (DT) have proven long-term efficacy and safety in patients ≥2 years old with chronic transfusional iron overload. However, barriers to optimal adherence remain, including palatability, preparation time, and requirements for fasting state. A new film-coated tablet (FCT) formulation was developed, swallowed once daily (whole/crushed) with/without a light meal. METHODS: The open-label, Phase II ECLIPSE study evaluated patient-reported outcomes (PROs) in transfusion-dependent thalassemia or lower-risk myelodysplastic syndromes patients randomized 1:1 to receive deferasirox DT or FCT over 24 weeks as a secondary outcome of the study. Three PRO questionnaires were developed to evaluate both deferasirox formulations: 1) Modified Satisfaction with Iron Chelation Therapy Questionnaire; 2) Palatability Questionnaire; 3) Gastrointestinal (GI) Symptom Diary. RESULTS: One hundred seventy three patients were enrolled; 87 received the FCT and 86 the DT formulation. FCT recipients consistently reported better adherence (easier to take medication, less bothered by time to prepare medication and waiting time before eating), greater satisfaction/preference (general satisfaction and with administration of medicine), and fewer concerns (less worry about not swallowing enough medication, fewer limitations in daily activities, less concern about side effects). FCT recipients reported no taste or aftertaste and could swallow all their medicine with an acceptable amount of liquid. GI summary scores were low for both formulations. CONCLUSIONS: These findings suggest a preference in favor of the deferasirox FCT formulation regardless of underlying disease or age group. Better patient satisfaction and adherence to chelation therapy may reduce iron overload-related complications. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT02125877; registered April 26, 2014.


Asunto(s)
Deferoxamina/uso terapéutico , Quelantes del Hierro/uso terapéutico , Síndromes Mielodisplásicos/tratamiento farmacológico , Medición de Resultados Informados por el Paciente , Satisfacción del Paciente , Talasemia/tratamiento farmacológico , Adulto , Transfusión Sanguínea , Terapia por Quelación/métodos , Femenino , Humanos , Sobrecarga de Hierro/prevención & control , Masculino , Persona de Mediana Edad , Síndromes Mielodisplásicos/psicología , Calidad de Vida , Talasemia/psicología
6.
Hemoglobin ; 42(3): 213-216, 2018 May.
Artículo en Inglés | MEDLINE | ID: mdl-30251901

RESUMEN

A 20-year-old male affected by transfusion-dependent ß-thalassemia (ß-thal), was prescribed intensive chelation therapy with deferoxamine (DFO) and deferiprone (DFP) because of severe hepatic and cardiac iron overload and ß-blocker and warfarin to manage a previous event of atrial fibrillation (AFib) and heart failure. After a few months, he developed critical liver failure, renal tubulopathy and severe electrolyte imbalance. Laboratory and instrumental evaluations were performed to carry out differential diagnosis of acute liver failure and an exclusion diagnosis of drug induced liver injury (DILI) was made. The cholestatic pattern suggested warfarin as the main causative agent and polypharmacy, liver iron overload and heart failure as aggravating factors. Warfarin is a drug commonly prescribed in thalassemia patients who often need polypharmacy for the management of anemia- and iron-related complications. Strict monitoring and multidisciplinary approaches are mandatory to avoid preventable mortality in this fragile population.


Asunto(s)
Enfermedad Hepática Inducida por Sustancias y Drogas/etiología , Sobrecarga de Hierro/complicaciones , Talasemia beta/complicaciones , Antagonistas Adrenérgicos beta , Terapia por Quelación/efectos adversos , Enfermedad Hepática Inducida por Sustancias y Drogas/diagnóstico , Enfermedad Crítica , Deferiprona , Insuficiencia Cardíaca/complicaciones , Insuficiencia Cardíaca/tratamiento farmacológico , Humanos , Sobrecarga de Hierro/tratamiento farmacológico , Masculino , Warfarina , Adulto Joven , Talasemia beta/terapia
7.
Eur J Haematol ; 94(4): 310-7, 2015 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-25081908

RESUMEN

OBJECTIVES: Bioavailability of deferasirox (DFX) is significantly affected by the timing of administration relative to times and to composition of meals. Its elimination half-life is also highly variable - in some patients as a result of gene polymorphisms. Understanding whether deferasirox plasma levels are related to specific characteristics of patients could help physicians to devise a drug regimen tailored the individual patient. METHODS: We analyzed deferasirox plasma concentrations (CDFX ) in 80 patients with transfusion-dependent anemias, such as thalassemia, by a high performance liquid chromatography (HPLC) assay. We used a multivariate linear regression model to find significant associations between CDFX and clinical/demographical characteristics of patients. All patients were genotyped for UGT1A1. RESULTS: Fifty-six patients were female, 24 were male, the great majority (88%) affected by ß-thalassemia, and 15 were children and adolescents. No statistical correlation was detectable between CDFX and DFX dose (P = 0.6). Age, time from last drug intake to blood sampling, and ferritin levels in the 6 months before study initiation were significantly and inversely associated with CDFX in univariate analysis. In the multivariate analysis, the only two factors independently and inversely associated with CDFX levels were time from last drug intake to blood sampling and ferritin levels (P = 0.006). A significant inverse correlation (P = 0.03) was observed between CDFX and UGT1A1*28 gene polymorphism, but only in patients with levels of lean body mass (LBM) below the median (P for interaction = 0.05). CONCLUSIONS: The results could indicate that a higher plasma DFX concentration could be associated with greater chelation efficacy. As a correlation between dose and CDFX was not demonstrated, it seems useful to monitor the concentrations to optimize and determine the most appropriate dose for each patient. Interesting results emerged from the analysis of genetic and physical characteristics of patients: LBM was a borderline significant effect modifier of the relationship between UGT1A1 polymorphisms and CDFX . Individual patient-tailored dosing of DFX should help to improve iron chelation efficacy and to reduce dose-dependent drug toxicity.


Asunto(s)
Benzoatos/farmacocinética , Quelantes del Hierro/farmacocinética , Farmacogenética , Triazoles/farmacocinética , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Anemia/diagnóstico , Anemia/etiología , Anemia/terapia , Benzoatos/administración & dosificación , Niño , Preescolar , Cromatografía Líquida de Alta Presión , Deferasirox , Femenino , Genotipo , Glucuronosiltransferasa/genética , Humanos , Quelantes del Hierro/administración & dosificación , Masculino , Persona de Mediana Edad , Polimorfismo Genético , Factores de Riesgo , Factores Sexuales , Resultado del Tratamiento , Triazoles/administración & dosificación , Adulto Joven
8.
Haematologica ; 99(12): 1876-84, 2014 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-25216685

RESUMEN

The pathogenesis of bone resorption in ß-thalassemia major is multifactorial and our understanding of the underlying molecular and cellular mechanisms remains incomplete. Considering the emerging importance of the endocannabinoid/endovanilloid system in bone metabolism, it may be instructive to examine a potential role for this system in the development of osteoporosis in patients with ß-thalassemia major and its relationship with iron overload and iron chelation therapy. This study demonstrates that, in thalassemic-derived osteoclasts, tartrate-resistant acid phosphatase expression inversely correlates with femoral and lumbar bone mineral density, and directly correlates with ferritin levels and liver iron concentration. The vanilloid agonist resiniferatoxin dramatically reduces cathepsin K levels and osteoclast numbers in vitro, without affecting tartrate-resistant acid phosphatase expression. The iron chelators deferoxamine, deferiprone and deferasirox decrease both tartrate-resistant acid phosphatase and cathepsin K expression, as well as osteoclast activity. Taken together, these data show that transient receptor potential vanilloid type 1 activation/desensitization influences tartrate-resistant acid phosphatase expression and activity, and this effect is dependent on iron, suggesting a pivotal role for iron overload in the dysregulation of bone metabolism in patients with thalassemia major. Our applied pharmacology provides evidence for the potential of iron chelators to abrogate these effects by reducing osteoclast activity. Whether iron chelation therapy is capable of restoring bone health in humans requires further study, but the potential to provide dual benefits for patients with ß-thalassemia major -preventing iron-overload and alleviating associated osteoporotic changes - is exciting.


Asunto(s)
Sobrecarga de Hierro/fisiopatología , Osteoporosis/etiología , Osteoporosis/metabolismo , Canales Catiónicos TRPV/metabolismo , Talasemia beta/complicaciones , Fosfatasa Ácida/genética , Fosfatasa Ácida/metabolismo , Adulto , Biomarcadores/metabolismo , Western Blotting , Estudios de Casos y Controles , Catepsina K/genética , Catepsina K/metabolismo , Células Cultivadas , Femenino , Técnica del Anticuerpo Fluorescente , Estudios de Seguimiento , Humanos , Quelantes del Hierro/farmacología , Isoenzimas/genética , Isoenzimas/metabolismo , Masculino , Osteoclastos/citología , Osteoclastos/efectos de los fármacos , Osteoclastos/metabolismo , Osteoporosis/tratamiento farmacológico , Pronóstico , ARN Mensajero/genética , Reacción en Cadena en Tiempo Real de la Polimerasa , Receptor Cannabinoide CB1/genética , Receptor Cannabinoide CB1/metabolismo , Receptor Cannabinoide CB2/genética , Receptor Cannabinoide CB2/metabolismo , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Canales Catiónicos TRPV/genética , Fosfatasa Ácida Tartratorresistente , Talasemia beta/metabolismo
9.
Am J Hematol ; 89(12): 1102-6, 2014 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-25197009

RESUMEN

Iron overload in ß-thalassemia major (TM) typically results in iron-induced cardiomyopathy, liver disease, and endocrine complications. We examined the incidence and progression of endocrine disorders (hypothyroidism, diabetes, hypoparathyroidism, hypogonadism), growth and pubertal delay, and bone metabolism disease during long-term deferasirox chelation therapy in a real clinical practice setting. We report a multicenter retrospective cohort study of 86 transfusion-dependent patients with TM treated with once daily deferasirox for a median duration of 6.5 years, up to 10 years. No deaths or new cases of hypothyroidism or diabetes occurred. The incidence of new endocrine complications was 7% (P = 0.338, for change of prevalence from baseline to end of study) and included hypogonadism (n = 5) and hypoparathyroidism (n = 1). Among patients with hypothyroidism or diabetes at baseline, no significant change in thyroid parameters or insulin requirements were observed, respectively. Mean lumbar spine bone mineral density increased significantly (P < 0.001) and the number of patients with lumbar spine osteoporosis significantly decreased (P = 0.022) irrespective of bisphosphonate therapy, hormonal replacement therapy, and calcium or vitamin D supplementation. There were no significant differences in the number of pediatric patients below the 5th centile for height between baseline and study completion. Six pregnancies occurred successfully, and four of them were spontaneous without ovarian stimulation. This is the first study evaluating endocrine function during the newest oral chelation therapy with deferasirox. A low rate of new endocrine disorders and a stabilization of those pre-exisisting was observed in a real clinical practice setting.


Asunto(s)
Benzoatos/uso terapéutico , Terapia por Quelación , Quelantes del Hierro/uso terapéutico , Sobrecarga de Hierro/tratamiento farmacológico , Osteoporosis/prevención & control , Triazoles/uso terapéutico , Talasemia beta/tratamiento farmacológico , Adolescente , Adulto , Densidad Ósea , Huesos/efectos de los fármacos , Huesos/metabolismo , Huesos/patología , Calcio/administración & dosificación , Niño , Preescolar , Deferasirox , Diabetes Mellitus/etiología , Diabetes Mellitus/metabolismo , Diabetes Mellitus/patología , Diabetes Mellitus/prevención & control , Difosfonatos/uso terapéutico , Femenino , Humanos , Hipogonadismo/etiología , Hipogonadismo/metabolismo , Hipogonadismo/patología , Hipogonadismo/prevención & control , Hipoparatiroidismo/etiología , Hipoparatiroidismo/metabolismo , Hipoparatiroidismo/patología , Hipoparatiroidismo/prevención & control , Hipotiroidismo/etiología , Hipotiroidismo/metabolismo , Hipotiroidismo/patología , Hipotiroidismo/prevención & control , Sobrecarga de Hierro/etiología , Sobrecarga de Hierro/metabolismo , Sobrecarga de Hierro/patología , Masculino , Persona de Mediana Edad , Osteoporosis/etiología , Osteoporosis/metabolismo , Osteoporosis/patología , Pubertad Tardía/etiología , Pubertad Tardía/metabolismo , Pubertad Tardía/patología , Pubertad Tardía/prevención & control , Estudios Retrospectivos , Vitamina D/administración & dosificación , Talasemia beta/complicaciones , Talasemia beta/metabolismo , Talasemia beta/patología
10.
Blood ; 118(4): 884-93, 2011 Jul 28.
Artículo en Inglés | MEDLINE | ID: mdl-21628399

RESUMEN

Patients with ß-thalassemia require lifelong iron chelation therapy from early childhood to prevent complications associated with transfusional iron overload. To evaluate long-term efficacy and safety of once-daily oral iron chelation with deferasirox, patients aged ≥ 2 years who completed a 1-year, phase 3, randomized trial entered a 4-year extension study, either continuing on deferasirox (deferasirox cohort) or switching from deferoxamine to deferasirox (crossover cohort). Of 555 patients who received ≥ 1 deferasirox dose, 66.8% completed the study; 43 patients (7.7%) discontinued because of adverse events. In patients with ≥ 4 years' deferasirox exposure who had liver biopsy, mean liver iron concentration significantly decreased by 7.8 ± 11.2 mg Fe/g dry weight (dw; n = 103; P < .001) and 3.1 ± 7.9 mg Fe/g dw (n = 68; P < .001) in the deferasirox and crossover cohorts, respectively. Median serum ferritin significantly decreased by 706 ng/mL (n = 196; P < .001) and 371 ng/mL (n = 147; P < .001), respectively, after ≥ 4 years' exposure. Investigator-assessed, drug-related adverse events, including increased blood creatinine (11.2%), abdominal pain (9.0%), and nausea (7.4%), were generally mild to moderate, transient, and reduced in frequency over time. No adverse effect was observed on pediatric growth or adolescent sexual development. This first prospective study of long-term deferasirox use in pediatric and adult patients with ß-thalassemia suggests treatment for ≤ 5 years is generally well tolerated and effectively reduces iron burden. This trial was registered at www.clinicaltrials.gov as #NCT00171210.


Asunto(s)
Benzoatos/uso terapéutico , Terapia por Quelación/métodos , Quelantes del Hierro/uso terapéutico , Triazoles/uso terapéutico , Talasemia beta/tratamiento farmacológico , Adolescente , Adulto , Benzoatos/administración & dosificación , Benzoatos/efectos adversos , Terapia por Quelación/efectos adversos , Niño , Preescolar , Estudios Cruzados , Deferasirox , Deferoxamina/uso terapéutico , Femenino , Estudios de Seguimiento , Crecimiento y Desarrollo/efectos de los fármacos , Humanos , Hierro/metabolismo , Quelantes del Hierro/administración & dosificación , Quelantes del Hierro/efectos adversos , Masculino , Persona de Mediana Edad , Triazoles/administración & dosificación , Triazoles/efectos adversos , Adulto Joven
11.
Vitam Horm ; 66: 457-591, 2003.
Artículo en Inglés | MEDLINE | ID: mdl-12852263

RESUMEN

Vitamin A is a very intriguing natural compound. The molecule not only has a complex array of physiological functions, but also represents the precursor of promising and powerful new pharmacological agents. Although several aspects of human retinol metabolism, including absorption and tissue delivery, have been clarified, the type and amounts of vitamin A derivatives that are intracellularly produced remain quite elusive. In addition, their precise function and targets still need to be identified. Retinoic acids, undoubtedly, play a major role in explaining activities of retinol, but, recently, a large number of physiological functions have been attributed to different retinoids and to vitamin A itself. One of the primary roles this vitamin plays is in embryogenesis. Almost all steps in organogenesis are controlled by retinoic acids, thus suggesting that retinol is necessary for proper development of embryonic tissues. These considerations point to the dramatic importance of a sufficient intake of vitamin A and explain the consequences if intake of retinol is deficient. However, hypervitaminosis A also has a number of remarkable negative consequences, which, in same cases, could be fatal. Thus, the use of large doses of retinol in the treatment of some human diseases and the use of megavitamin therapy for certain chronic disorders as well as the growing tendency toward vitamin faddism should alert physicians to the possibility of vitamin overdose.


Asunto(s)
Vitamina A/fisiología , Adolescente , Adulto , Animales , Niño , Preescolar , Digestión , Desarrollo Embrionario y Fetal , Femenino , Humanos , Lactante , Recién Nacido , Absorción Intestinal , Lactancia , Política Nutricional , Necesidades Nutricionales , Estado Nutricional , Embarazo , Complicaciones del Embarazo , Vitamina A/administración & dosificación , Vitamina A/efectos adversos , Deficiencia de Vitamina A
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