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2.
J Nutr ; 154(8): 2363-2373, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-38797483

RESUMEN

BACKGROUND: Vitamin A (VA) deficiency and excess negatively affect development, growth, and bone health. The World Health Organization's standard of care for xerophthalmia due to VA deficiency, is 3 high-dose VA supplements of 50,000-200,000 IU, based on age, which may cause hypervitaminosis A in some individuals. OBJECTIVES: This study measured VA status following 3 VA doses in 2 piglet studies. METHODS: In Study 1, 5 groups of piglets (n = 10/group) were weaned 10 d postbirth to VA-free feed and orally administered 0; 25,000; 50,000; 100,000; or 200,000 IU VA ester on days 0, 1, and 7. On days 14 and 15, the piglets underwent the modified relative dose-response (MRDR) test for VA deficiency, and were killed. Tissues were collected for high-pressure liquid chromatography analysis. Study 2 used the same design in 3 groups (n = 13/group) weaned at 16 d and administered 0; 25,000; and 200,000 IU doses. RESULTS: In Study 1 (final weight: 3.6 ± 0.7 kg), liver VA concentration was hypervitaminotic in 40%, 90%, and 100% of 50,000; 100,000; and 200,000 IU groups, respectively. The 25,000 IU group was 100% adequate, and the placebo group was 40% deficient. In Study 2 (final weight: 8.7 ± 0.8 kg), where 200,000 IU could be prescribed to infants with a similar body weight, 31% of the piglets were hypervitaminotic, the 25,000 IU group was 100% VA adequate, and the placebo group was 100% deficient. The MRDR test measured deficiency in 50% and 70% of the placebo group in each study but had 3 false positives among hypervitaminotic piglets in Study 1. CONCLUSIONS: Repeated high-dose VA may cause hypervitaminosis, indicating dose sizes may need reduction. The MRDR resulted in false positives in a hypervitaminotic state during malnutrition and should be paired with serum retinyl ester evaluation to enhance VA status assessment in populations with overlapping interventions.


Asunto(s)
Suplementos Dietéticos , Hipervitaminosis A , Vitamina A , Xeroftalmia , Animales , Vitamina A/administración & dosificación , Porcinos , Xeroftalmia/tratamiento farmacológico , Relación Dosis-Respuesta a Droga , Enfermedades de los Porcinos/tratamiento farmacológico , Deficiencia de Vitamina A/tratamiento farmacológico , Deficiencia de Vitamina A/veterinaria , Femenino , Masculino , Hígado/metabolismo , Hígado/efectos de los fármacos
3.
Acta Biomed ; 94(3): e2023098, 2023 06 14.
Artículo en Inglés | MEDLINE | ID: mdl-37326274

RESUMEN

BACKGROUND AND AIM: Vitamin A toxicity is uncommon, but when it occurs can be serious and even fatal. A case vitamin A intoxication with high levels in liver tests, thrombocytopenia and appearance virosis. Laboratory testing is one of the most widely used diagnostic interventions supporting medical decisions of this phenomenon are necessary. CASE REPORT: Here, we report a case vitamin A intoxication with high levels in liver tests, thrombocytopenia and appearance virosis. The patient showed several clinical signs abdominal pain, including mild anemia and thrombocytopenia. CONCLUSIONS: We believe that Laboratory testing is one of the most widely used diagnostic interventions supporting medical decisions, and further investigations regarding the etiology and prevalence of this phenomenon are necessary. (www.actabiomedica.it).


Asunto(s)
Anemia , Hipervitaminosis A , Trombocitopenia , Humanos , Hipervitaminosis A/complicaciones , Hipervitaminosis A/diagnóstico , Vitamina A , Anemia/etiología , Trombocitopenia/inducido químicamente , Trombocitopenia/diagnóstico
4.
Clin Toxicol (Phila) ; 60(11): 1277-1281, 2022 11.
Artículo en Inglés | MEDLINE | ID: mdl-36286587

RESUMEN

Douglas Mawson is a national hero of Australia, having led the Australasian Antarctic expedition of 1911, and survived. His three-man sledging team was beset by a series of catastrophes. First, expert skier Belgrave Ninnis died after he fell into a deep crevasse taking with him half the dogs and a sledge of essential food and supplies. The remaining two explorers immediately turned back to base which was 315 miles away. With their rations diminished they resorted to eating their remaining six dogs over 23 days. Xavier Mertz became progressively ill with diarrhea, delirium, vocal outbursts in rages, and finally several seizures. He died after another seizure. Mawson, alone with negligible food and no dogs for transportation, through his own sheer grit made it back to base camp a month later and was saved. His journal records medical complications with skin desquamation, alopecia, and muscle pain. It has been proposed that these symptoms in both Mertz and Mawson were the manifestations of hypervitaminosis A. They likely consumed greater than a 1,200,000 IU of vitamin A each day from the dog liver they decided was essential to eat to survive. Mertz, a vegetarian, possibly consumed more of the liver than muscle meat, and consequently suffered the more severe encephalopathy and seizures associated with acute vitamin A poisoning.


Asunto(s)
Expediciones , Hipervitaminosis A , Masculino , Humanos , Vitamina A , Regiones Antárticas , Convulsiones/inducido químicamente
6.
Am J Clin Nutr ; 115(4): 1059-1068, 2022 04 01.
Artículo en Inglés | MEDLINE | ID: mdl-35030234

RESUMEN

BACKGROUND: Excessive vitamin A (VA) can cause bone resorption and impair growth. Government-mandated VA supplementation (VAS) and adequate intake through dietary fortification and liver consumption led to excessive VA in South African children. OBJECTIVES: We evaluated the relation between VAS and underlying hypervitaminosis A assessed by retinol isotope dilution (RID) with measures of growth and bone turnover in this cohort. METHODS: Primary outcomes in these children (n = 94, 36-60 mo) were anthropometric measurements [height-for-age (HAZ), weight-for-age (WAZ), and weight-for-height (WHZ) z scores], serum bone turnover markers [C-terminal telopeptide of type I collagen (CTX) and N-terminal propeptide of type I procollagen (P1NP)], and inflammation defined as C-reactive protein (CRP; ≥5 mg/L) and/or α1-acid glycoprotein (AGP; ≥1 g/L). VA status was previously measured by RID-estimated total body VA stores (TBSs) and total liver VA reserves (TLRs), and serum retinol and carotenoid concentrations, before and 4 wk after children were administered 200,000 IU VAS. Serum 25-hydroxyvitamin D3 was measured by ultra-performance LC. RESULTS: In this largely hypervitaminotic A cohort, HAZ, WAZ, and WHZ were negatively associated with increasing TLRs, where TLRs predicted 6-10% of the variation before VAS (P < 0.05), increasing to 14-19% 4 wk after VAS (P < 0.01). Bone resorption decreased after VAS (P < 0.0001), whereas formation was unaffected. Neither CTX nor P1NP were correlated with TLRs at either time. Serum carotenoids were low. One child at each time point was vitamin D deficient (<50 nmol/L). CRP and AGP were not associated with growth measurements. CONCLUSIONS: Excessive TLRs due to dietary VA intake and VAS are associated with lower anthropometric measures and bone resorption decreased after supplementation. VA supplementation programs should monitor VA status with biomarkers sensitive to TLRs to avoid causing negative consequences in children with hypervitaminosis A. This trial is registered at clinicaltrials.gov as NCT02915731.


Asunto(s)
Hipervitaminosis A , Deficiencia de Vitamina A , Preescolar , Dieta , Humanos , Sudáfrica , Vitamina A
7.
BMC Vet Res ; 18(1): 18, 2022 Jan 06.
Artículo en Inglés | MEDLINE | ID: mdl-34991571

RESUMEN

BACKGROUND: Deficiencies in vitamin A and D and disorders in the vitamin B complex are often present in people with chronic liver diseases. So far, the serum concentrations of these vitamins have not yet been studied in dogs with congenital extrahepatic portosystemic shunts (EHPSS), who also have some degree of liver dysfunction. The objective was to assess serum vitamin concentrations in dogs with EHPSS from diagnosis to complete closure. A prospective cohort study was performed using ten client-owned dogs with EHPSS, closed after gradual surgical attenuation. Serum concentrations of vitamin A, 25-hydroxyvitamin D, folic acid, cobalamin and methylmalonic acid (MMA) were measured at diagnosis prior to institution of medical therapy, prior to surgery, and three months after gradual attenuation and complete closure of the EHPSS. RESULTS: At diagnosis, median serum concentrations of vitamin A, 25-hydroxyvitamin D and folic acid were 18.2 µg/dL (8.8 - 79.5 µg/dL), 51.8 ng/mL (19.4 - 109.0 ng/mL), and 8.1 µg/L (5.2 - 14.5 µg/L), respectively, which increased significantly postoperatively (88.3 µg/dL (51.6 - 182.2 µg/dL, P=0.005), 89.6 ng/mL (49.3 - >150.0 ng/mL, P =0.005), and 14.8 µg/L (11.5 - 17.7 µg/L, P <0.001), respectively). Median serum cobalamin concentrations were 735.5 ng/L (470 - 1388 ng/L) at diagnosis and did not significantly decrease postoperatively (P =0.122). Both at diagnosis and three months postoperatively 7/10 dogs had hypercobalaminemia. CONCLUSIONS: Serum concentrations of vitamin A, 25-hydroxyvitamin D and folic acid significantly increase after surgical attenuation. Nevertheless, persistent hypercobalaminemia is suggestive of ongoing liver dysfunction, despite successful surgery.


Asunto(s)
Perros , Sistema Porta , Deficiencia de Vitamina B 12 , Animales , Estudios de Cohortes , Perros/anomalías , Perros/sangre , Perros/cirugía , Ácido Fólico/sangre , Hipervitaminosis A/veterinaria , Sistema Porta/anomalías , Sistema Porta/cirugía , Estudios Prospectivos , Vitamina A/sangre , Vitamina B 12/sangre , Deficiencia de Vitamina B 12/veterinaria , Vitamina D/análogos & derivados , Vitamina D/sangre
8.
J Ren Nutr ; 32(3): 275-281, 2022 05.
Artículo en Inglés | MEDLINE | ID: mdl-34103212

RESUMEN

OBJECTIVE: Hypervitaminosis A is well-described but overlooked in chronic kidney disease (CKD) and has been associated with hypercalcemia, contributing to mineral bone disease. Our objective is to assess prevalence of hypervitaminosis A and its association with bone health in an advanced-CKD population. METHODS: We performed a retrospective review of 58 children with CKD 4-5 to examine the association between vitamin A levels and bone health and compared these values between a primarily formula-fed (FF) and nonprimarily formula-fed cohort (NFF). RESULTS: Fifty-six of 58 patients (97%) had hypervitaminosis A with a mean vitamin A level of 1,475 ± 597 mcg/dL. When compared with the upper limit of normal vitamin A level for age, the FF group's vitamin A level was 2.9x upper limit of normal and the NFF group's vitamin A level was 2.2x upper limit of normal (P = .02). The mean calcium level was 10.3 mg/dL in the FF group and 9.8 mg/dL in the NFF group (P = .057). Percent of patients lower than, within, or greater than goal parathyroid hormone range was statistically significant with 15 (62%) of the FF group lower than goal and 16 (72%) of the NFF cohort greater than goal (P = .006). CONCLUSIONS: We concluded vitamin A and calcium levels are higher in the FF versus the NFF population. FF patients are more likely to have parathyroid hormone levels lower than the goal range, placing them at risk for adynamic bone disease. We recommend monitoring vitamin A levels as part of routine nutritional assessments and dietary interventions to prevent hypervitaminosis A to improve bone health in late CKD.


Asunto(s)
Enfermedades Óseas , Hipervitaminosis A , Insuficiencia Renal Crónica , Enfermedades Óseas/complicaciones , Calcio , Niño , Femenino , Humanos , Hipervitaminosis A/complicaciones , Masculino , Hormona Paratiroidea , Insuficiencia Renal Crónica/complicaciones , Vitamina A , Vitamina D
11.
Wilderness Environ Med ; 31(4): 454-456, 2020 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-32861618

RESUMEN

In European countries, vitamin A toxicity is most often the result of an excessive intake of vitamin supplements and rarely the consequence of the ingestion of a large carnivorous fish liver. We report 3 cases of vitamin A poisoning after fish liver ingestion in mainland and overseas France. The patients were a 12-y-old girl, a 36-y-old pregnant woman, and a 62-y-old man. They experienced headache, nausea, emesis, and desquamation. Laboratory examination showed a high serum retinol level in the girl. The woman's pregnancy progressed to a miscarriage. This case series shows that this kind of poisoning is not restricted to the polar regions. In patients presenting with flushing combined with signs of intracranial hypertension, accurate questioning of the patient's diet is crucial to avoid misdiagnosis and unnecessary examinations. Pregnant women or women of child-bearing age should be informed of the risk to pregnancy in the case of excessive fish liver ingestion.


Asunto(s)
Peces , Enfermedades Transmitidas por los Alimentos/etiología , Hipervitaminosis A/etiología , Hígado , Centros de Control de Intoxicaciones , Vitamina A/sangre , Adulto , Animales , Niño , Femenino , Francia , Humanos , Hipervitaminosis A/sangre , Hipervitaminosis A/patología , Masculino , Persona de Mediana Edad , Embarazo , Complicaciones del Embarazo
12.
Eur J Clin Microbiol Infect Dis ; 39(11): 2091-2098, 2020 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-32607910

RESUMEN

For people living with HIV, determinants of immunological non-response (INR) to combined antiretroviral therapy (cART) have not been fully elucidated. In a case-control study, we evaluated the influence of the nutritional and antioxidant status in HIV-1 adults whose cART was initiated between January 2001 and December 2013. Cases had persistent CD4 counts < 350/µL vs. > 350/µL for controls, after at least 2 years of cART with persistent viral loads (VL) < 50 copies/mL. Twelve cases and twenty-eight control subjects with the same CD4 count at cART initiation were compared for their nutritional and antioxidant status after age adjustment at dosage assessment. Patients were predominantly male (70%), Caucasian (82%) and at AIDS stage (62%). The median age was 53, and the median CD4 count was 245/mm3 for cases and 630/mm3 for controls after a median time of 7 years on cART. Despite higher energy intakes in cases, anthropometric data was comparable between groups who had similar vitamins B9/B12/C/D/E, zinc, citrulline and glutamine levels. Nine cases (75%) and 8 controls (29%) had hypervitaminosis A (> 2.70 µmol/L) (p = 0.030). Cases had lower erythrocyte resistance when exposed to a controlled free radical attack (p = 0.014). Most cases had hypervitaminosis A and altered antioxidant capacities that could affect immunological response. Wide-scale studies are required, but in the meantime, screening of their vitamin A status must be encouraged in these patients.


Asunto(s)
Infecciones por VIH , VIH-1 , Hipervitaminosis A/epidemiología , Adolescente , Adulto , Recuento de Linfocito CD4 , Estudios de Casos y Controles , Femenino , Francia/epidemiología , Humanos , Hipervitaminosis A/sangre , Hipervitaminosis A/etiología , Masculino , Persona de Mediana Edad , Carga Viral , Adulto Joven
15.
Artículo en Inglés | MEDLINE | ID: mdl-31546693

RESUMEN

Rubella is a systemic virus infection that is usually mild. It can, however, cause severe birth defects known as the congenital rubella syndrome (CRS) when infection occurs early in pregnancy. As many as 8%-13% of children with CRS developed autism during the rubella epidemic of the 1960s compared to the background rate of about 1 new case per 5000 children. Rubella infection and CRS are now rare in the U.S. and in Europe due to widespread vaccination. However, autism rates have risen dramatically in recent decades to about 3% of children today, with many cases appearing after a period of normal development ('regressive autism'). Evidence is reviewed here suggesting that the signs and symptoms of rubella may be due to alterations in the hepatic metabolism of vitamin A (retinoids), precipitated by the acute phase of the infection. The infection causes mild liver dysfunction and the spillage of stored vitamin A compounds into the circulation, resulting in an endogenous form of hypervitaminosis A. Given that vitamin A is a known teratogen, it is suggested that rubella infection occurring in the early weeks of pregnancy causes CRS through maternal liver dysfunction and exposure of the developing fetus to excessive vitamin A. On this view, the multiple manifestations of CRS and associated autism represent endogenous forms of hypervitaminosis A. It is further proposed that regressive autism results primarily from post-natal influences of a liver-damaging nature and exposure to excess vitamin A, inducing CRS-like features as a function of vitamin A toxicity, but without the associated dysmorphogenesis. A number of environmental factors are discussed that may plausibly be candidates for this role, and suggestions are offered for testing the model. The model also suggests a number of measures that may be effective both in reducing the risk of fetal CRS in women who acquire rubella in their first trimester and in reversing or minimizing regressive autism among children in whom the diagnosis is suspected or confirmed.


Asunto(s)
Trastorno Autístico/inducido químicamente , Hipervitaminosis A/complicaciones , Hepatopatías/complicaciones , Síndrome de Rubéola Congénita/inducido químicamente , Rubéola (Sarampión Alemán)/fisiopatología , Vitamina A/toxicidad , Humanos , Hipervitaminosis A/inducido químicamente , Hígado/metabolismo , Virus de la Rubéola/fisiología , Vitamina A/metabolismo
16.
Ir Med J ; 112(6): 953, 2019 06 17.
Artículo en Inglés | MEDLINE | ID: mdl-31538442

RESUMEN

There is an increasing literature with regard to vitamin D supplementation in Multiple Sclerosis (MS). We report the case of a 45 year-old male with MS who presented with symptomatic hypercalcaemia secondary to self-supplementation of vitamin D3 purchased online. Treatment was with IV hydration, glucocorticoids, calcitonin and bisphosphonates. This case highlights a lack of consensus guidance regarding safe vitamin D supplementation dosages and the importance of a thorough history with regard to non-prescribed supplements, particularly those easily available online.


Asunto(s)
Hipercalcemia/etiología , Hipervitaminosis A/complicaciones , Esclerosis Múltiple/complicaciones , Suplementos Dietéticos , Humanos , Masculino , Persona de Mediana Edad
17.
BMC Musculoskelet Disord ; 20(1): 287, 2019 Jun 15.
Artículo en Inglés | MEDLINE | ID: mdl-31202274

RESUMEN

BACKGROUND: A vitamin A derivative, 13-cis-retinoic acid (isotretinoin), has been administered to treat several types of pediatric cancer and has improved survival rates in patients despite being known to induce premature epiphyseal closure. As the number of patients treated by 13-cis-retinoic acid increases, demands for salvage treatment after systemic retinoid therapy are emerging. However, few studies have described the surgical treatment of this disease. CASE PRESENTATION: We report a case with bilateral varus knee deformity due to premature epiphyseal closure that occurred during treatment with isotretinoin for neuroblastoma. The patient was successfully treated with correction osteotomy using a Taylor spatial frame in the right knee joint and femoral closed wedge osteotomy using a locking plate in left knee joint. Histopathological examination of the growth plate showed polar irregularity of chondrocytes and decreased cartilage matrix without apoptosis. In contrast, arthroscopic findings showed an intact joint surface. No recurrence of varus deformity was evident on follow-up at 1 year. CONCLUSIONS: To the best of our knowledge, this represents the first report of correction osteotomy for varus knee deformity due to premature epiphyseal closure that occurred during treatment with isotretinoin.


Asunto(s)
Placa de Crecimiento/fisiopatología , Hipervitaminosis A/complicaciones , Articulación de la Rodilla/cirugía , Osteoartritis de la Rodilla/cirugía , Osteotomía/métodos , Placas Óseas , Niño , Femenino , Fémur/diagnóstico por imagen , Fémur/fisiopatología , Fémur/cirugía , Humanos , Hipervitaminosis A/inducido químicamente , Hipervitaminosis A/fisiopatología , Isotretinoína/efectos adversos , Imagen por Resonancia Magnética , Neuroblastoma/tratamiento farmacológico , Osteoartritis de la Rodilla/diagnóstico por imagen , Osteoartritis de la Rodilla/etiología , Osteotomía/instrumentación , Tibia/diagnóstico por imagen , Tibia/fisiopatología , Tibia/cirugía , Resultado del Tratamiento
18.
Arch Osteoporos ; 14(1): 72, 2019 06 28.
Artículo en Inglés | MEDLINE | ID: mdl-31254130

RESUMEN

This analysis was performed in Zambian children who had a high prevalence of hypervitaminosis A, defined as > 1.0 µmol retinol/g liver. Bone parameters included markers of bone formation (P1NP), bone resorption (CTX), parathyroid hormone, calcium, vitamin A, and vitamin D. Low dietary vitamin A intake increased P1NP. PURPOSE: Vitamin A (VA) interacts with bone health, but mechanisms require clarification. In countries where multiple interventions exist to eradicate VA deficiency, some groups are consuming excessive VA. Bone metabolism and inflammatory parameters were measured in Zambian children who had high prevalence of hypervitaminosis A determined by 13C-retinol isotope dilution. METHODS: Children (n = 143), 5 to 7 years, were recruited into a placebo-controlled biofortified orange maize feeding study for 90 days. Bone turnover (P1NP and CTX) and inflammatory (C-reactive protein (CRP) and alpha-1-acid glycoprotein) biomarkers were measured in fasting blood samples before and/or after intervention with the following: (1) VA at the recommended dietary allowance (400 µg retinol activity equivalents/day (as retinyl palmitate)), (2) maize enhanced with the provitamin A carotenoid ß-carotene (2.86 mg/day), or (3) a placebo. Parathyroid hormone, calcium, and 25(OH)-vitamin D were measured at end line. RESULTS: Bone formation, as measured by P1NP, increased (P < 0.0001) in the placebo group who consumed low preformed VA during the intervention. Bone resorption, measured by CTX, was not affected. P1NP and CTX were negatively associated with inflammation, most strongly with CRP. Serum calcium did not differ among groups and was low (7.29 ± 0.87 µg/dL). Serum 25(OH) D did not differ among groups (54.5 ± 15 nmol/L), with 91% < 75 nmol/L and 38% < 50 nmol/L. CONCLUSIONS: Reduction of dietary preformed VA in Zambian children for 4 months improved bone formation. Chronic consumption of preformed VA caused hypervitaminosis A and may impair bone formation. In children, this could be associated with failure to accrue optimal peak bone mass. TRIAL REGISTRATION: The NIH Clinical Trial registry number is NCT01814891; https://clinicaltrials.gov/ct2/show/NCT01814891 .


Asunto(s)
Remodelación Ósea , Hipervitaminosis A/dietoterapia , Osteogénesis , Vitamina A/efectos adversos , Biomarcadores/sangre , Proteína C-Reactiva , Niño , Preescolar , Dieta , Diterpenos , Femenino , Humanos , Hígado , Masculino , Estado Nutricional , Hormona Paratiroidea/sangre , Provitaminas , Ésteres de Retinilo , Vitamina A/análogos & derivados , Vitaminas , Zea mays
19.
Am J Clin Nutr ; 110(1): 91-101, 2019 07 01.
Artículo en Inglés | MEDLINE | ID: mdl-31089689

RESUMEN

BACKGROUND: In some regions, multiple vitamin A (VA) interventions occur in the same target groups, which may lead to excessive stores. Retinol isotope dilution (RID) is a more sensitive technique than serum retinol to measure VA status. OBJECTIVE: We evaluated VA status before and after a high-dose supplement in preschool children living in a region in South Africa with habitual liver consumption and exposed to VA supplementation and fortification. METHODS: After baseline blood samples, subjects (46.7 ± 8.4 mo; n = 94) were administered 1.0 µmol [14,15]-13C2-retinyl acetate to estimate total liver retinol reserves by RID with a follow-up 14-d blood sample. Liver intake was assessed with a frequency questionnaire. In line with current practice, a routine 200,000 IU VA capsule was administered after the RID test. RID was repeated 1 mo later. Serum retinyl esters were evaluated using ultra-performance liquid chromatography. RESULTS: At baseline, 63.6% of these children had hypervitaminosis A defined as total liver retinol reserves ≥1.0 µmol/g liver, which increased to 71.6% after supplementation (1.13 ± 0.43 to 1.29 ± 0.46 µmol/g; P < 0.001). Total serum VA as retinyl esters was elevated in 4.8% and 6.1% of children before and after supplementation. The odds of having hypervitaminosis A at baseline were higher in children consuming liver ≥1/mo (ratio 3.70 [95% CI: 1.08, 12.6]) and in children receiving 2 (4.28 [1.03, 17.9]) or 3 (6.45 [0.64, 65.41]) supplements in the past 12 mo. Total body stores decreased after the supplement in children in the highest quartile at baseline compared with children with lower stores, who showed an increase (P = 0.007). CONCLUSIONS: In children, such as this cohort in South Africa, with adequate VA intake through diet, and overlapping VA fortification and supplementation, preschool VA capsule distribution should be re-evaluated. This trial was registered at https://clinicaltrials.gov/ct2/show/NCT02915731 as NCT02915731.


Asunto(s)
Dieta , Alimentos Fortificados , Hipervitaminosis A/sangre , Hígado , Ovinos , Vitamina A/administración & dosificación , Animales , Preescolar , Suplementos Dietéticos , Alimentos Fortificados/análisis , Humanos , Hígado/química , Sudáfrica , Vitamina A/análisis , Vitamina A/sangre
20.
J Toxicol Sci ; 44(4): 257-271, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-30944279

RESUMEN

Vitamin A and its derivatives contribute to many physiological processes, including vision, neural differentiation, and reproduction. Vitamin A deficiency causes early cessation of spermatogenesis, characterized by a marked depletion of germ cells. However, there has been no clear understanding about the role of chronic intake of vitamin A excess (VAE) in spermatogenesis. The objective of this study was to investigate whether chronic intake of VAE diet causes arrest of spermatogenesis. To examine the effects of VAE on spermatogenesis, we used ICR male mice fed with control (AIN-93G purified diet: 4 IU/g) diet or VAE (modified AIN-93G diet with VAE: 1,000 IU/g) diet for 7 weeks (from 3 to 10 weeks of age). At 10 weeks of age, the retinol concentration in the testes of VAE mice was significantly higher than that of control mice. Testicular cross sections from control mice contained a normal array of germ cells, while the seminiferous tubules from VAE mice exhibited varying degrees of testicular degeneration. Daily sperm production in VAE testes was dramatically decreased compared to that in control testes. Sperm viability, motility, and morphology were also impaired in VAE mice. Furthermore, we examined the effects of VAE on the expression of genes involved in retinoid signaling and spermatogenesis to determine the underlying molecular mechanisms. Therefore, we are the first to present results describing the long-term dietary intake of VAE impairs spermatogenesis using a mouse model.


Asunto(s)
Exposición Dietética/efectos adversos , Hipervitaminosis A/etiología , Hipervitaminosis A/fisiopatología , Espermatogénesis/efectos de los fármacos , Vitamina A/administración & dosificación , Vitamina A/efectos adversos , Animales , Modelos Animales de Enfermedad , Relación Dosis-Respuesta a Droga , Femenino , Hipervitaminosis A/metabolismo , Masculino , Ratones Endogámicos ICR , Embarazo , Retinoides , Transducción de Señal/genética , Motilidad Espermática/efectos de los fármacos , Espermatogénesis/genética , Espermatozoides/efectos de los fármacos , Espermatozoides/patología , Testículo/efectos de los fármacos , Testículo/metabolismo , Testículo/patología , Factores de Tiempo , Vitamina A/metabolismo
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