Serum Level of Biotin Rather than the Daily Dosage Is the Main Determinant of Interference on Thyroid Function Assays.

INTRODUCTION: Several case reports stress that high-dose biotin causes incorrect laboratory results. However, the extent of this interference in children is not systematically studied. AIM: To assess factors associated with biotin interference on thyroid function tests in subjects with biotinidase deficiency. METHOD: The study included 44 children who were treated with oral biotin (Group 1, median dose: 10 mg/day [25-75p; 10-10], age: 1.83 years [1.04-2.90]) and 30 healthy subjects (Group 2, age: 1.05 years [0.37-3.37]). Thyroid function tests were performed with two different assays, and streptavidin-coated particles were used in order to remove biotin from serum samples of cases with biotin interference. RESULTS: The measurements were first performed with Beckman Coulter. In Group 1, remarkably high levels of fT3 and fT4 were found in 26 (59.1%) and 25 (56.8%) patients, respectively. Thyroid hormone functions were all normal in Group 2. Significantly higher serum biotin levels were detected in interference-positive children (p < 0.001). The serum biotin levels in Group 1 showed a strong positive correlation with fT3 (r = 0.867, p < 0.001) and fT4 levels (r = 0.905, p < 0.001). A serum biotin level of 80.35 µg/L was found to be the best cut-off value for predicting interference (sensitivity: 96.2% and specificity: 94.4%). When analyzed with Siemens Advia Centaur XP, all thyroid function tests were normal in both groups except in one patient (2.27%) with slightly elevated fT3 level in Group 1. Repeated tests with Beckman Coulter after neutralization of biotin with streptavidin magnetic particles in serum samples of the interference-positive cases revealed normal thyroid hormone levels. CONCLUSION: Interference is an important problem in thyroid function tests in nearly 60% of all children receiving biotin treatment for biotinidase deficiency. Serum levels of biotin rather than the dosage are the main determinant of interference, which can be eliminated by choosing appropriate laboratory methods.

Positive correlation of galanin with insulin resistance and triglyceride levels in obese children

Background/aim: Galanin is a neuropeptide that is shown to be involved in the regulation of food intake and glucose homeostasis. The objective of this study was to evaluate the relation of serum galanin levels with anthropometric and metabolic parameters in obese and healthy children. Material and methods: The cross-sectional study consisted of 38 obese children (mean age: 11.9 ± 3.0 years) and 30 healthy children (mean age: 11.4 ± 2.0 years). Clinical and biochemical parameters [glucose, insulin, homeostasis model assessment-insulin resistance (HOMA-IR), lipids, galanin, and leptin levels] were assessed. Results: Serum galanin and leptin levels were significantly higher in obese children. In obese children, galanin levels were positively correlated with fasting glucose (r = 0.398, p = 0.013), insulin (r = 0.383, p = 0.018), HOMA-IR (r = 0.375, p = 0.020), and triglycerides (r = 0.391, p=0.015). Multivariate backward regression analysis revealed that galanin levels were significantly associated with fasting glucose, insulin, HOMA-IR, and triglyceride, which explained 42.0% of the variance (r2 = 0.483, P < 0.001). Conclusions: Serum galanin levels were significantly higher in obese children than healthy controls and positively correlated with insulin resistance and triglycerides in obese children. This study suggests that galanin is associated with glucose homeostasis and lipid metabolism in childhood obesity.

Increased concentrations of serum nesfatin-1 levels in childhood with idiopathic chronic malnutrition

Background/aim: Nesfatin-1, an anorexigenic molecule, seems to play a role in appetite regulation and energy homeostasis. The goal of this study was to evaluate the relation of nesfatin-1 with anthropometric and metabolic (ghrelin, leptin) parameters in children with idiopathic chronic malnutrition. Materials and methods: The study included 37 underweight and 38 healthy children who were similar regarding age, sex, and pubertal status. Anthropometric and biochemical (nesfatin-1, ghrelin, and leptin levels) variables were assessed. Results: A total of 37 underweight subjects (mean age 10.5 ± 2.6 years) and 38 heathy subjects (mean age 10.3 ± 2.3 years) were recruited. Underweight children had significantly higher nesfatin-1 (2.76 ± 0.4 vs. 1.56 ± 0.7, P < 0.001) and lower leptin levels (2.21 ± 2.0 vs. 5.21 ± 2.4, P < 0.001) than those of the control subjects. Nesfatin-1 levels were significantly associated with only leptin levels, after adjusting for age and BMI (r = ­0.371, P = 0.001). Conclusion: The present study is the first to evaluate nesfatin-1 levels in relation with anthropometric and metabolic parameters in children with chronic malnutrition, who were subsequently found to have significantly higher nesfatin-1 levels. Our study underlines that nesfatin-1 may play a role in the development of malnutrition by inhibiting food intake in children.

Serum galectin-1 levels are positively correlated with body fat and negatively with fasting glucose in obese children.

Galectin-1, a recently identified peptide, is primarily released from the adipose tissue. Although galectin-1 was shown to have an anti-inflammatory effect, its specific function is not clearly understood. We aimed to evaluate the relationship of serum galectin-1 levels with clinical and laboratory parameters in childhood obesity. A total of 45 obese children (mean age: 12.1±3.1years) and 35 normal-weight children (mean age: 11.8±2.2years) were enrolled. Clinical [body mass index (BMI), waist circumference (WC), percentage of body fat and blood pressure] and biochemical [glucose, insulin, lipids, galectin-1, high-sensitive C-reactive protein (hsCRP) and leptin levels] parameters were assessed. Serum galectin-1, hsCRP and leptin levels were significantly higher in obese children than those in normal-weight children (12.4 vs 10.2ng/mL, p<0.001; 3.28 vs 0.63mg/L, p<0.001; 8.3 vs 1.2ng/mL, p<0.001, respectively). In obese children, galectin-1 levels correlated negatively with fasting glucose (r=-0.346, p=0.020) and positively with fat mass (r=0.326, p=0.026) and WC standard deviation score (SDS) (r=0.451, p=0.002). The multivariate regression analysis demonstrated that serum galectin-1 levels were significantly associated with fasting glucose and WC SDS. This study showed that obese children had significantly higher galectin-1 levels in proportion to fat mass in obese cases than those in healthy children, which may be interpreted as a compensatory increase in an attempt to improve glucose metabolism.

The Relationship between Serum Zonulin Level and Clinical and Laboratory Parameters of Childhood Obesity.

OBJECTIVE: To investigate the relationship between zonulin levels and clinical and laboratory parameters of childhood obesity. METHODS: The study included obese children with a body mass index (BMI) >95th percentile and healthy children who were of similar age and gender distribution. Clinical (BMI, waist circumferences, mid-arm circumference, triceps skinfold, percentage of body fat, systolic blood pressure, diastolic blood pressure) and biochemical (glucose, insulin, lipid levels, thyroid function tests, cortisol, zonulin and leptin levels) parameters were measured. RESULTS: A total of 43 obese subjects (23 males, mean age: 11.1±3.1 years) and 37 healthy subjects (18 males, mean age: 11.5±3.5 years) were included in this study. Obese children had significantly higher insulin, homeostasis model assessment of insulin resistance, triglyceride, total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol (HDL-C), zonulin and leptin levels than healthy children (p<0.05), while glucose levels were not different (p>0.05). Comparison of the obese children with and without insulin resistance showed no statistically significant differences for zonulin levels (p>0.05). Zonulin levels were found to negatively correlate with HDL-C and positively correlate with leptin levels, after adjusting for age and BMI. CONCLUSION: To the best of our knowledge, this is the first study investigating the relationship between circulating zonulin level (as a marker of intestinal permeability) and insulin resistance and leptin (as markers of metabolic disturbances associated with obesity) in childhood obesity. The results showed that zonulin was significantly higher in obese children when compared to healthy children, a finding indicating a potential role of zonulin in the etiopathogenesis of obesity and related disturbances.

Increased adipsin is associated with carotid intima media thickness and metabolic disturbances in polycystic ovary syndrome.

CONTEXT: Adipsin, a protein secreted mainly from the adipose tissue, is a structural homologous of complement factor D, a rate-limiting enzyme of the alternative complement system. Growing evidence suggests that the alternative complement system plays a role both in the regulation of energy homoeostasis and in the atherosclerosis. Polycystic ovary syndrome (PCOS) is a reproductive and metabolic disease. OBJECTIVE: To ascertain whether circulating adipsin levels are altered in women with PCOS, and whether there is an association between adipsin and metabolic parameters or carotid intima media thickness (CIMT). PARTICIPANTS: A total of 144 women with PCOS and 144 age- and BMI-matched controls without PCOS were recruited for this cross-sectional study. MAIN OUTCOME MEASURES: Circulating adipsin levels were measured using ELISA. Metabolic, hormonal parameters and CIMT were also determined. RESULTS: Adipsin levels were significantly elevated in women with PCOS compared with controls (91·52 ± 14·11 vs 60·31 ± 9·71 ng/ml, P < 0·001). Adipsin positively correlated with BMI, homoeostasis model assessment of insulin resistance (HOMA-IR), free testosterone, high-sensitivity C-reactive protein (hs-CRP) and CIMT in both groups. Multivariate logistic regression analyses revealed that the odds ratio for PCOS was 3·25 for patients in the highest quartile of adipsin compared with those in the lowest quartile (OR=3·25, 95% CI=2·64-4·00, P = 0·016). Our findings further indicate that BMI, HOMA-IR, hs-CRP and free testosterone are independent factors influencing serum adipsin levels and that adipsin is an independent predictor for CIMT. CONCLUSION: Circulating adipsin levels are significantly higher in women with PCOS, and the peptide is closely related to increased cardiovascular risk and metabolic disturbances.

Elevated circulating levels of betatrophin are associated with polycystic ovary syndrome.

Betatrophin is a newly identified hormone determined to be a potent inducer of pancreatic beta cell proliferation in response to insulin resistance in mice. Polycystic ovary syndrome (PCOS) is an inflammatory-based metabolic disease associated with insulin resistance. However, no evidence is available indicating whether betatrophin is involved in women with PCOS. The objective of this study was to ascertain whether betatrophin levels are altered in women with PCOS. This study was conducted in secondary referral center. This cross-sectional study included 164 women with PCOS and 164 age- and BMI-matched female controls. Circulating betatrophin levels were measured using ELISA. Metabolic and hormonal parameters were also determined. Circulating betatrophin levels were significantly elevated in women with PCOS compared with controls (367.09 ± 55.78 vs. 295.65 ± 48.97 pg/ml, P < 0.001). Betatrophin levels were positively correlated with insulin resistance marker homeostasis model assessment of insulin resistance (HOMA-IR), free-testosterone, high-sensitivity C-reactive protein (hs-CRP), atherogenic lipid profiles, and BMI in PCOS. Multivariate logistic regression analyses revealed that the odds ratio for PCOS was 2.51 for patients in the highest quartile of betatrophin compared with those in the lowest quartile (95 % CI 1.31-4.81, P = 0.006). Multivariate regression analyses showed that HOMA-IR, hs-CRP, and free-testosterone were independent factors influencing serum betatrophin levels. Betatrophin levels were increased in women with PCOS and were associated with insulin resistance, hs-CRP, and free-testosterone in these patients. Elevated betatrophin levels were found to increase the odds of having PCOS. Further research is needed to elucidate the physiologic and pathologic significance of our findings.