Biol Trace Elem Res DOI 10.1007/s12011-016-0831-z
Selenium Status in Patients with Turner Syndrome: a Biochemical Assessment Related with Body Composition Liliane Viana Pires 1 & Adriana Aparecida Siviero-Miachon 2 & Angela Maria Spinola-Castro 2 & José Alexandre Coelho Pimentel 1 & Luciana Sigueta Nishimura 1 & Carla Soraya Costa Maia 3 & Silvia Maria Franciscato Cozzolino 1
Received: 12 March 2016 / Accepted: 19 August 2016 # Springer Science+Business Media New York 2016
Abstract Studies about selenium status in patients with Turner syndrome (TS) are non-existent in the literature. The aim of this study was to evaluate selenium status in patients with TS, while considering the different ages of the studied population and the relation with body composition. In total, 33 patients with TS were evaluated and grouped according to their developmental stages (children, adolescents, and adults). Selenium concentrations in their plasma, erythrocytes, urine, and nails were determined by using hydride generation atomic absorption spectrometry and erythrocyte glutathione peroxidase activity were measured by using Randox commercial kits. Additionally, height, weight, body fat percentage, waist circumference, and waist-height ratio were measured to characterize the patients. No differences in the selenium concentrations in the plasma, erythrocyte, urine, and nails or in the glutathione peroxidase activity were observed among the age groups (p > 0.05). The evaluated selenium levels were less than the established normal ones. The patients with larger waist circumference, body fat percentage, body mass index, and waist-height ratio showed lower glutathione peroxidase enzyme activity (p = 0.023). The present study shows that most patients with TS are deficient in selenium and that those
* Liliane Viana Pires
[email protected];
[email protected]
1
Department of Food and Experimental Nutrition, Faculty of Pharmaceutical Sciences, University of São Paulo, Av. Professor Lineu Prestes, n°580, Cidade Universitária, São Paulo, SP 05508-900, Brazil
2
Division of Pediatric Endocrinology, Department of Pediatrics, Federal University of São Paulo, São Paulo, Brazil
3
Department of Nutrition, State University of Ceara, Ceara, Brazil
with a greater accumulation of body fat have a lower GPx activity. Keywords Turner syndrome . Selenium . Glutathione peroxidase . Nutritional status . Fat body
Introduction Turner syndrome (TS) is a female-phenotype anomaly and occurs in a live-birth proportion ranging from 1:2500 to 1:5000 individuals. This syndrome is caused by the presence of an X chromosome and a total or partial loss of the second sexual chromosome [1, 2]. The phenotypic characteristics of TS are as follows: short stature (final height between 142 and 147 cm) and gonadal dysgenesis leading to primary amenorrhea, late pubertal development, and sterility [2–5]. Some congenital or acquired anomalies may also occur including cardiovascular and renal anomalies, hearing deficiency, hypertension, thyroid diseases, osteoporosis, and obesity [2]. To our knowledge, no study has evaluated selenium status in populations with TS. Many biological functions of selenium are carried out by selenoproteins, including the families of enzymes glutathione peroxidase (GPx) and thioredoxin reductases that protect against oxidative injury [6–8]. There are also are selenium dependent enzymes iodothyronine deiodinases, which has the function to regulate the active form of thyroid hormone in tissues [6, 9]. Thus, a selenium deficiency has been associated with several pathological conditions such as oxidative stress, inflammation, immune system defects, and thyroid gland dysfunction, such as hypothyroidism, common in TS [9, 10]. In most studies, selenium status was assessed by determining its concentration in whole blood, serum, plasma, erythrocytes, urine,
Pires et al.
or hair, and by determining GPx activity in whole blood [11–13]. Another highlight is the increased body fat in this population. There are still few studies that reported an association between selenium status and body composition. A study based on SU.VI.MAX showed that obese women (BMI >30 kg/m2) had lower concentrations of selenium in the serum than normal weight woman [14]. Data from the nationally representative cross-sectional survey, the National Health and Nutrition Examination Survey III (NHANES III), revealed that the high prevalence of selenium deficiency is related to women being overweight and obese prior to menopause [15]. Additionally, a high BMI has been associated with a decrement in whole blood GPx activity [16]. Knowledge of the relationship between an increase in body fat and selenium status, and deficiency in particular, may improve our understanding of the role of selenium in obesityrelated diseases in this population. The present study aimed at determining GPx activity in the blood and selenium concentration in the blood, nails, and urine of the patients with TS. Therefore, we determined a relationship between the principal anthropometric parameters and selenium status.
Material and Methods Subjects The present study included 33 patients with TS that were grouped according to age (8 children, 19 adolescents, and 6 adults) and who had visited the Division of Pediatric Endocrinology, Federal University of São Paulo (Brazil). Participants were recruited from July 2007 to January 2008. The diagnosis was confirmed using karyotype analysis. Initially, a questionnaire was prepared to obtain information about the research inclusion criteria (information such as use of vitamin-mineral supplements or drugs that could interfere with the selenium status). The absence of a healthy group in this study was justified by the non-equivalence of hormonal factors and pubertal development in the healthy individuals and in the patients with TS [17]. Ethical Considerations This study was conducted according to the guidelines established by the Declaration of Helsinki, and all the procedures involving human subjects/patients were approved by the Ethics Committee of the Faculty of Pharmaceutical Sciences of the University of São Paulo (EC # 128/2006). Informed consent was obtained from all individual participants included in the study.
Experimental Design This was a cross-sectional study. The blood, urine, and nails samples were collected for the evaluation of selenium concentration and erythrocyte GPx activity. Body composition was evaluated by determining weight, height, waist circumference, percentage body fat, waist-height ratio, and BMI. Because of the lack of data on the selenium content in foods produced in Brazil, an assessment of dietary intake for these patients was not performed. Anthropometric Evaluation and Body Fat Percentage A specific curve for TS drawn by the Growth Analyzer 3 software, as described by Karlberget [18], was utilized for classifying children and adolescents with TS according to their height and age. BMI was calculated by dividing the current weight (kg) by the squared height (m2). The result was analyzed according to the BMI-of-age percentile (2000-CDC/NCHS-Centers for Disease Control and Prevention/National Center for Health Statistics) [19] in the adolescents and according to the WHO [20] in the adults with TS. Waist circumference was measured midway between the lowest rib and the top of the iliac crest. Additionally, the waist-to-height ratio of patients with TS was calculated; this has been used as an important predictor of cardiovascular risk [21, 22]. The percentage of fat of the participants was assessed by using bioelectrical impedance analysis (biodynamics model) [23]. Blood Samples The blood samples (12 mL) were collected in morning after 12 h of fasting. The blood was collected in the presence of ethylenediaminetetraacetic acid. The plasma was separated from the whole blood by centrifuging at 3000 rpm for 15 min at 4 °C and stored at −80 °C until the analysis of selenium concentration. The erythrocytes were washed thrice with 5 mL of 0.9 % solution of sodium chloride, slowly homogenized by turning the container upside down, and then centrifuged at 10,000 rpm for 10 min at 4 °C. The washed erythrocytes were stored at −80 °C until the selenium levels and GPx activity were analyzed. Urine Samples The urine samples were collected and stored in previously demineralized containers without preservatives. The samples were stored at −20 °C until the selenium levels were analyzed.
Selenium Status in Patients with Turner Syndrome Table 1 Characterization of patients with Turner syndrome according to the development phase
Response variable
Child
Adolescent
Adult
PSDa
p valueb
p valuec
Age (years) Weight (kg) Height (cm) Waist circumference (cm) Body fat (%) BMI (kg/m2) Waist to height ratio Se plasma (μg/L)d Se erythrocyte (μg/L)e Se urine (μg/mL)f Se nails (μg/g)g GPx activity (U/g Hb)
7.00c 23.12b 114.24b 57.29b 15.14b 17.97b 0.50b 44.86 56.92 6.77 0.340 38.07
15.05b 44.90a 140.76a 71.11a 19.73b 22.29a 0.51b 43.60 59.04 6.42 0.365 41.44
21.14a 52.41a 140.80a 81.43a 27.57a 26.40a 0.58a 38.59 52.19 6.51 0.507 34.04
5.36 14.45 13.91 11.33 7.56 4.85 0.06 12.39 12.89 3.2 0.206 12.14
0.176 0.051 0.462 0.211 0.561 0.065 0.283 0.907 0.880 0.848 0.010 0.063
