Sexual dimorphism in relationship of serum leptin and relative weight for the standard in normal-weight, but not in overweight, children as well as adolescents

Abnormal adipose tissue distribution with unfavorable metabolic profile in five children following hematopoietic stem cell transplantation: a new etiology for acquired partial lipodystrophy

We report five consecutive patients who underwent hematopoietic stem cell transplantation (HSCT) to treat leukemia or neuroblastoma early in their lives and later manifested abnormal patterns of adipose tissue distribution. Lipoatrophy was remarkable in the gluteal regions and extremities, whereas subcutaneous fat was preserved in the cheeks, neck, and abdomen. In addition, visceral fat deposition, fatty changes in the liver, and metabolic derangements such as insulin resistance and hypertriglyceridemia were evident. These features resemble Dunnigan-type familial partial lipodystrophy, which is a rare condition caused by LMNA gene mutation. These patients shared a common medical history involving HSCT, including conditioning with total body irradiation (TBI). They also received intensive chemotherapy because of multiple metastases (n = 3), relapse (n = 3), and repetitive HSCT (n = 3). We propose HSCT as a new etiology for acquired partial lipodystrophy and recommend that patients who undergo HSCT with TBI and intensive chemotherapy early in their lives must receive careful observation for the possible development of lipodystrophy and metabolic complications.

Abnormal adipose tissue distribution with unfavorable metabolic profile in five children following hematopoietic stem cell transplantation: a new etiology for acquired partial lipodystrophy

We report five consecutive patients who underwent hematopoietic stem cell transplantation (HSCT) to treat leukemia or neuroblastoma early in their lives and later manifested abnormal patterns of adipose tissue distribution. Lipoatrophy was remarkable in the gluteal regions and extremities, whereas subcutaneous fat was preserved in the cheeks, neck, and abdomen. In addition, visceral fat deposition, fatty changes in the liver, and metabolic derangements such as insulin resistance and hypertriglyceridemia were evident. These features resemble Dunnigan-type familial partial lipodystrophy, which is a rare condition caused by LMNA gene mutation. These patients shared a common medical history involving HSCT, including conditioning with total body irradiation (TBI). They also received intensive chemotherapy because of multiple metastases (n = 3), relapse (n = 3), and repetitive HSCT (n = 3). We propose HSCT as a new etiology for acquired partial lipodystrophy and recommend that patients who undergo HSCT with TBI and intensive chemotherapy early in their lives must receive careful observation for the possible development of lipodystrophy and metabolic complications.

Lentiviral vector-mediated knockdown of Lrb in the arcuate nucleus promotes diet-induced obesity in rats

Obesity is currently a worldwide pandemic. Leptin resistance is a main mechanism of obese human and rodents. The downregulation of the long form of the leptin receptor (Lrb) was involved in leptin resistance in diet-induced obese rats. In the studies, we investigated whether arcuate nucleus (ARC) silencing of Lrb would promote diet-induced obesity in rats. Lentiviral vectors expressing Lrb-shRNA were administered to 5-week-old male rats by ARC injection. Following viral delivery, the rats were provided with a high-fat diet (HFD) or a chow diet (CD). After 8 weeks of the diet, serum leptin, and insulin concentrations were measured by RIA, gene expression of Lrb in the ARC was detected by a real-time RT-PCR, and leptin signaling was examined by western blot. The Lrb-shRNA knocked down the expression of Lrb mRNA in infected regions by 54% for the HFD rats and 47% for the CD rats respectively. The Lrb knockdown reduced Stats3 activation and increased expression of Npy mRNA. The rats with reduced Lrb in the ARC showed a significant increase in energy intake and body weight (BW) again when fed with a HFD. By contrast, there were no effects of Lrb reduction on energy intake or BW when rats maintained on a low-fat chow. Our results provide evidence that Lrb knockdown selectively in the ARC promotes diet-induced obesity and associated metabolic complications in rats.

Lentiviral vector-mediated knockdown of SOCS3 in the hypothalamus protects against the development of diet-induced obesity in rats

AIM

Leptin resistance is a feature of most cases of obesity in both humans and rodents. The suppressor of cytokine signalling 3 (SOCS3) is a negative-feedback regulator of leptin signalling involved in leptin resistance; therefore, the suppression of SOCS3 is a potential therapy for leptin resistance in obesity. In the studies, we investigated whether hypothalamic silencing of SOCS3 would attenuate diet-induced obesity in rats.

METHODS

First we established hypothalamic SOCS3-deficient rats through lentiviral vector (LV)-mediated RNA interference (RNAi) technique, then provided a high-fat diet or a chow diet to the rats. After 8 weeks of the diet, the serum leptin and insulin concentrations were measured by RIA, and the gene expressions of SOCS3 and the long form of leptin receptor in hypothalamus were detected by a real time RT-PCR. The leptin-induced Stat3 activation was examined by Western blot.

RESULTS

The RNAi protocol specifically knocked down the expression of SOCS3 mRNA by 50% approximately. The rats treated with LV-SOCS3-shRNA exhibited enhanced leptin-induced Stat3 activation, decreased body weight gain and improved metabolic parameters when exposed to a high-fat diet.

CONCLUSION

Our results provide evidence that the rats treated with hypothalamic SOCS3 silencing are significantly protected against the development of diet-induced obesity and SOCS3 is a potential target molecule for therapeutic intervention of obesity.

Age and sex differences in fat distribution in non-obese Japanese children

OBJECTIVE

To assess fat distribution in non-obese Japanese children and adolescents.

DESIGN

130 non-obese Japanese children (73 boys and 57 girls) from Kikugawa, Hamamatsu were included. The visceral fat area (VFA) and subcutaneous fat area (SFA) were measured by computed tomography (CT) and calculated (in cm(2)). Subjects were divided into three groups based on age: group A (6-10 years), group B (11-15 years), and group C (16-20 years).

RESULTS

Girls had more subcutaneous fat than boys in groups B and C (P<0.01). Boys had an age-dependent increase in visceral fat, but girls did not. In group C (16-20 years), boys had more visceral fat than girls (P<0.01).

CONCLUSIONS

In non-obese Japanese children, there are significant differences in visceral and subcutaneous fat amounts by age and sex. VFA seems to accumulate more in boys than in girls, and SFA is more prevalent in girls than boys.

Taurine in morning spot urine for the useful assessment of dietary seafood intake in Japanese children and adolescents

Background

Since our previous report on WHO CARDIAC Study data demonstrated that 24-hour urinary (24U) taurine (Tau) excretion was a useful biomarker of seafood (SF) intake and inversely related to the mortality rates of stroke and coronary heart diseases in the world, we determined that SF is important in the risk reduction of lifestyle related-diseases. The amounts of dietary SF intake are so far estimated from a nutritional survey or 24U Tau excretion.

The sodium/potassium ratio of spot urine (SU) and the 24U ratio were reported to be significantly correlated with. Therefore, we presently examined the relationship of Tau excretion in the morning SU with 24U Tau for simplifying the population comparison and the follow-up of SF intake changes in the process of food education program (FEP).

Methods

After informed consent was obtained, 54 children aged 6-11 years (Children) and 193 adolescents aged 13-18 years (Adolescents) participated in collecting precisely 24U and SU of the first urination on the same day and answered the questionnaire including age and height and weight measurements. The urine samples were measured for creatinine (Cre) and Tau, and the association of these between 24U and SU were analyzed.

Results

The success rates of 24U sampling were very high in Children and Adolescents, 96.4% and 82.4%, respectively. From the result of the multiple regression analysis of SU Tau/Cre and weight we obtained formulas for predicting 24U Tau excretion in Children and Adolescents as follows: Children: 24U Tau = 16.3 (weight) + 314.3 (SU Tau/Cre) -175.2; and Adolescents: 24U Tau = 20.2 (weight) + 644.7 (SU Tau/Cre) - 569.4.

Conclusions

The present study established the regression equation to estimate 24U Tau excretion from SU Tau/Cre and weight. These formulas are expected to contribute to the estimation of fish and SF intake and the follow-up of the change of the dietary behavior by FEP in Children and Adolescents.

Reliability of bioimpedance analysis compared with other adiposity measurements in children: The FLVS II Study

OBJECTIVE

To evaluate the reproducibility of the measurement of% body fat by bipedal biometrical impedance analysis (BIA) compared with anthropometric measurements of adiposity in children and the correlations between these methods in children and adults.

METHODS

A cross-sectional study in a total of 1080 adults and children enrolled in 1999 in the Fleurbaix-Laventie Ville Santé II (FLVS II) population-based study in northern France. The reproducibility of anthropometrical and BIA methods was determined by a nested analysis of variance of repeated measurements by 2 investigators and a bipedal BIA device (Tanita TBF 310) in 64 pupils of two 5th grade classes. The correlation of BIA and anthropometric adiposity measurements with the unknown relative fat mass or volume of the body estimated by a latent adiposity variable (LAV) was established by the triads' method in 1080 subjects of the FLVS II cohort.

RESULTS

The reproducibility was similar for the sum of skinfolds, waist circumference and BIA% fat measurements (intraclass correlation coefficients: 0.979-0.992). Correlation coefficient between BIA body fat% and the LAV was higher than 0.86 in all sex and Tanner stage related groups, and similar in children and adults, except in pubertal boys (0.76).

CONCLUSION

With a high level of reproducibility, foot-to-foot BIA analysis provides a valuable measurement of total% fat for epidemiologic studies in children. However further studies are needed before extrapolating these results to overweight children.

Effects of leptin and dexamethasone on long and short leptin receptor mRNA

BACKGROUND

Leptin exerts its effects by using both long (OB-Rb) and short (OB-Ra) receptors. Although leptin resistance or insensitivity is reported to be a cause of human obesity, there have not been enough studies to clarify regulation of leptin receptors.

METHODS

The authors studied leptin receptor regulation by leptin and dexamethasone in the human hepatocellular carcinoma cell (HepG2). Using a quantitative RT-PCR technique, the authors demonstrate expression of OB-Ra and OB-Rb mRNA after the incubation for 24 h with leptin or dexamethasone at various concentrations (10(-9)-10(-6) M).

RESULTS

Leptin (10(-7)-10(-6) M) significantly inhibited expression of OB-Rb mRNA, with maximum inhibition (43% of control) at 10(-6) M. Expression of OB-R219.1 and OB-R219.3, two short isoforms of leptin receptor, were also reduced in cells treated with leptin most remarkably at 10(-7) M for OB-R219.1 (44% of the control) and at 10(-6) M for Ob-R219.3 (49% of the control). In contrast, dexamethasone (10(-8)-10(-6) M) significantly increased OB-Rb mRNA levels, with a maximum increase (204% of the control) at 10(-7) M, and OB-R219.1 and OB-R219.3 mRNA expression was also markedly increased at 10(-9)-10(-6) M. The peak values were 254% of the control for OB-R219.1 and 246% of the control for OB-R219.3 at 10(-7) M.

CONCLUSIONS

In HepG2 cells, leptin inhibits and dexamethasone increases OB-Ra and OB-Rb mRNA expression. It is suggested that glucocorticoids as well as leptin itself contribute to regulatory effects of leptin through changes in gene expression of leptin receptors.