Mehmet Emre Taşçılar

Cardiac Autonomic Functions in Obese Children

Objective: The autonomic nervous system is assumed to have a role in the pathophysiology of obesity. In this study, we evaluated the autonomic system by measuring heart rate variability (HRV) in obese children. Methods: Thirty-two obese and 30 healthy children (mean ages: 11.6±2.0 years and 11.0±2.9 years, respectively) were enrolled in the study. Obesity was defined as a body mass index higher than 97th percentile for age- and gender-specific reference values. All participants were free of any disease and none of them was receiving any medication. Twenty-four-hour ambulatory electrocardiographic recordings were obtained and the time-domain and frequency-domain indices of HRV were analyzed. The study group was evaluated with respect to insulin resistance by HOMA-IR values. Results: A significant decrease in calculated HRV variables was observed in obese children as compared to controls. The HRV alteration was found in both time-domain and frequency-domain parameters. The subgroup analysis of the study group revealed a significant decrease in all investigated HRV parameters in the insulin-resistant obese children compared to the non-insulin-resistant obese ones. Conclusions: Our results indicate that HRV is decreased in obese children, which implies parasympathetic withdrawal and sympathetic predominance. A marked decrease in HRV was observed in insulin-resistant obese children compared to their non-insulin-resistant counterparts. We propose that autonomic imbalance pertaining especially to insulin resistance may be involved in the pathogenesis of obesity in pediatric patients Conflict of interest:None declared.

P300 auditory event‐related potentials in children with obesity: is childhood obesity related to impairment in cognitive functions?

Tascilar ME, Turkkahraman D, Oz O, Yucel M, Taskesen M, Eker I, Abaci A, Dundaroz R, Ulas UH. P300 auditory event‐related potentials in children with obesity: is childhood obesity related to impairment in cognitive functions?

Threshold value of subepicardial adipose tissue to detect insulin resistance in obese children

Aim:Until now, the association between subepicardial adipose tissue (SAT), insulin resistance and intima–media thickness (IMT) has not been evaluated in obese children. In this study, we evaluated whether echocardiographic SAT is related to insulin resistance and IMT in obese children.Subjects and Methods:A total of 46 obese subjects (10.2±2.5 years of age, 25 male patients) and 30 age- and gender-matched lean subjects (10.8±3.1 years of age, 13 male patients) were included in this study. The criterion for diagnosing obesity was defined as the body mass index (BMI) being over 97% percentile of the same gender and age. Serum triglyceride (TG), low- and high-density lipoprotein, cholesterol, glucose and insulin levels were measured during the fasting state. Each subject underwent a transthoracic echocardiogram and the SAT thickness was measured during end-diastole from the parasternal long-axis views.Results:The obese subjects had significantly higher SAT thickness and IMT values compared with the subjects in the control group (5.7±1.4 vs 3.0±0.7 mm, 0.78±0.15 vs 0.51±0.11 mm, P=0.001, respectively). Simple linear regression analysis showed no significant correlation between SAT and insulin resistance (r=0.170, P=0.253), whereas there was significant correlation between SAT and BMI, age and IMT (r=0.625, P=0.02, r=0.589, P=0.001, r=0.343, P=0.02, respectively). As an optimal cutoff point, a SAT thickness of 4.1 mm determined insulin resistance with 90% sensitivity and 61% specificity.Conclusions:Our study showed that SAT was significantly correlated with age, BMI and IMT, but not insulin resistance. However, our findings suggest that a 4.1 mm cutoff of SAT thickness might be used as a simple, inexpensive and non-invasive screening method because of its ability to predict insulin resistance with high sensitivity in obese children.

Oxidative stress in obese children and its relation with insulin resistance.

Abstract Background: In obese populations, oxidative stress plays a major role in the pathogenesis of serious diseases such as diabetes, coronary heart disease, and atherosclerosis. In this study, we investigated the status of oxidative stress in obese children as to nitrite/nitrate and glutathione peroxidase levels, and their relation with insulin resistance (IR). Methods: A total of 63 obese children were enrolled in the study. Each was relegated to one of three groups: 20 obese children without IR (11 adolescents, 9 prepubertal; mean age 10.27±2.36 years; 10 males, 10 females), 22 obese children with IR (13 adolescents, 9 prepubertal; mean age 11.26±2.52 years; 10 males, 12 females), and a control group of 21 children (14 adolescents, 7 prepubertal; mean age 11.41±2.00 years; 10 males, 11 females). Results: Glutathione peroxidase levels were lower in the obese group with IR than in either the control group or the obese group without IR (0.032±0.01 vs. 0.048±0.01 and 0.042±0.01, respectively). Nitrite/nitrate levels were higher in the obese group with IR than in the control group or the obese group without IR (89.83±25.00 vs. 66.00±21.75, and 68.65±28.98, respectively) and compared by pubertal status, adolescents’ results were similar. However, in prepubertal children, nitrite/nitrate and glutathione peroxidase levels were not significantly different between groups. Multiple regression analysis revealed that nitrite/nitrate levels were positively correlated with the homeostasis model assessment of IR (HOMA-IR) independent of body mass index, age, gender, serum lipids, and pubertal stages, and that glutathione peroxidase levels were negatively correlated with body mass index and HOMA-IR independent of age, gender, pubertal status, and serum lipids. Conclusion: This study demonstrates that oxidative stress exists even in populations of obese children, and that oxidative stress markers have a relation with the HOMA-IR, which was used as a surrogate marker of IR.

The Effect of Insulin Resistance and Obesity on Low-Density Lipoprotein Particle Size in Children

Objective: In adults, it was shown that obesity and insulin resistance affect low−density lipoprotein (LDL) particle size and small dense (sd) LDL is associated with cardiovascular diseases. In this study, we investigated the effect of obesity and insulin resistance on LDL particle size. Methods: Twenty−six obese children (13 girls, 13 boys) with a median age of 10.5 years and 27 healthy control subjects (17 girls, 10 boys) with a median age of 11.5 were enrolled in the study. Results: The number of patients with insulin resistance in the obese group was 15 out of 26. In the control group, there was no subject with insulin resistance. Serum triglyceride and very LDL (VLDL) levels were higher and serum high−density lipoprotein levels (HDL) were lower in the obese patients than in the controls. There was no statistical difference in the LDL particle size between the two groups (medians: 26.6 vs. 26.7 nm (p=0.575)). The size of LDL particle was not correlated with body mass index (BMI) standard deviation score (SDS), homeostasis model assessment of insulin resistance (HOMA−IR), or serum lipids. Conclusion: Measurement of LDL particle size as a routine procedure is not necessary in childhood obesity. Conflict of interest:None declared.

Serum chitotriosidase activity: is it a new inflammatory marker in obese children?

Abstract Chitotriosidase (ChT) is an enzyme secreted by activated macrophages and involved in defense against, and in degradation of chitin-containing pathogens, such as fungi, nematodes, and insects. In addition, it plays an important role in the development of atherosclerosis related with systemic low-grade inflammation. To this effect of activity of ChT, we aimed to investigate serum ChT activity in obese subjects and to determine to relation with insulin resistance and high-sensitive C-reactive protein (hsCRP). A total of 73 obese subjects (10.9±2.6 years of age, 44 male patients) and 41 age and gender-matched healthy lean subjects (11.6±2.9 years of age, 18 male patients) were included in this study, between 2007 and 2008. The criterion for diagnosing obesity was defined as the body mass index (BMI) being over 97th percentile of the same gender and age. Fasting serum glucose, insulin, hsCRP and ChT levels were measured. We compared the differences in variables between obese and lean subjects with Student’s t-test compared after ascertaining that the data were normally distributed. All data were expressed as mean±standard deviation. There was statistically significant increase in serum ChT activity of obese subjects, while there was statistically significant difference in serum hsCRP levels when compared to healthy lean subjects (30.0±17.9 and 23.0±17.8, p=0.045; 2.3±3.1 and 0.7±1.2, p=0.001). Obese subjects had significantly higher BMI-SDS, TG and HOMA-IR and lower HDL-C levels when compared with the healthy lean subjects (p<0.05). Correlation analysis showed no significant correlation between serum ChT activity and hsCRP, HOMA-IR and BMI-SDS (p>0.05). Although the data need to be validated by further investigation, the observations made in this study seem to indicate that serum ChT activity may not be a useful marker for monitoring systemic low-grade inflammation and insulin resistance in obese subjects.

Osteopetrosis and congenital hypothyroidism complicated by slipped capital femoral epiphysis.

OBJECTIVE To describe a 13-year-old girl with unilateral slipped capital femoral epiphysis (SCFE), who presented with an acute onset limp during follow-up for congenital hypothyroidism and osteopetrosis. METHODS We present a case report detailing the patients history as well as clinical, laboratory, and imaging findings and discuss the related literature. RESULTS The patient had been diagnosed elsewhere with congenital hypothyroidism, and levothyroxine therapy was initiated when she was 20 days of age; however, adherence to the treatment was irregular. Both her weight and her height were below the 5th percentile, her breast development and pubic hair were consistent with Tanner stage 1, and she had mental retardation and atypical facies. Her gait was antalgic; no muscle atrophy or shortness in the affected leg was present. On laboratory investigation, thyroid function tests were concordant with primary hypothyroidism. Her bone age was estimated as 8 years. Dual-energy x-ray absorptiometry revealed increased bone mineral density. Radiographic studies disclosed striking opacity of the bones of the pelvis and sclerosis at the skull base. Computed tomography of the affected left lower limb showed a fragmented appearance of the capital femoral epiphysis and thickening and irregularities of the physis line on the left, consistent with SCFE. CONCLUSION We underscore the possible facilitator role of osteopetrosis in the pathogenesis of SCFE, suggest the need to consider SCFE in the differential diagnosis when a lower extremity abnormality is detected in patients with congenital hypothyroidism or delayed puberty (or both), and emphasize this association with osteopetrosis.

Association of nerve conduction impairment and insulin resistance in children with obesity.

AimThe objective of our study was to investigate nerve conduction in normoglycemic obese children.MethodsA total of 60 children with obesity (30 female and 30 male) and 30 healthy children (15 female and 15 male) were enrolled in the study. Insulin resistance (IR) and other metabolic disturbances were investigated and nerve conduction was measured in all participants. Obese children were divided into groups according to the presence of IR. All results were compared between these subgroups.ResultsThe nerve conduction velocity (NCV) of motor median nerves in the IR+ group was significantly higher than that in the IR− group and lower than that in the control group. The NCV of the motor peroneal nerve in the IR+ group was significantly lower than that in the IR− group. The sensory nerve action potential (SNAP) of the sensory median nerve was significantly lower in the IR+ group compared to that in the IR− group. The sensory sural nerve’s SNAP was significantly lower in the IR+ group than that in the control group.ConclusionNerve conduction tests may help to detect early pathologies in peripheral nerves and to decrease morbidities in obese children.

Visual and brainstem auditory evoked potentials in children with obesity

AIMS The aim of our study is to investigate alterations in visual evoked potentials (VEP) and brainstem auditory evoked potentials (BAEP) in children with obesity. METHODS A total of 96 children, with a mean age of 12.1±2.0 years (range 9-17 years, 63 obese and 33 age and sex-matched control subjects) were included in the study. Laboratory tests were performed to detect insulin resistance (IR) and dyslipidemia. The latencies and amplitudes of VEP and BAEP were measured in healthy and obese subjects. RESULTS The VEP P100, BAEP interpeak latency (IPL) I-III and IPL I-V averages of obese children were significantly longer than the control subjects. When the obese group was divided into two subgroups, those with IR and without IR, BAEP wave I, wave III and P100 wave latencies were found to be longer in the group with IR. A statistically significant correlation was observed between BAEP wave I latency, IPL I-V, IPL I-III and the homeostatic model assessment insulin resistance (HOMA IR) index and fasting insulin level. CONCLUSIONS Our findings suggest that VEP and BAEP can be used to determine early subclinical on auditory and visual functions of obese children with insulin resistance.

Relation of insulin resistance to neurocognitive function and electroencephalography in obese children.

Abstract Background: Childhood obesity may lead to neuronal impairment in both the peripheral and the central nervous system. This study aimed to investigate the impact of obesity and insulin resistance (IR) on the central nervous system and neurocognitive functions in children. Methods: Seventy-three obese children (38 male and 35 female) and 42 healthy children (21 male and 21 female) were recruited. Standard biochemical indices and IR were evaluated. The Wechsler Intelligence Scale for Children-Revised (WISC-R) and electroencephalography (EEG) were administered to all participants. The obese participants were divided into two groups based on the presence or absence of IR, and the data were compared between the subgroups. Results: Only verbal scores on the WISC-R in the IR+ group were significantly lower than those of the control and IR– groups. There were no differences between the groups with respect to other parameters of the WISC-R or the EEG. Verbal scores of the WISC-R were negatively correlated with obesity duration and homeostatic model assessment-insulin resistance (HOMA-IR) values. EEGs showed significantly more frequent ‘slowing during hyperventilation’ (SDHs) in obese children than non-obese children. Conclusions: Neurocognitive functions, particularly verbal abilities, were impaired in obese children with IR. An early examination of cognitive functions may help identify and correct such abnormalities in obese children.