Serum leptin concentrations in children with mild-to-moderate protein-energy malnutrition

Leptin Elevation as a Risk Factor for Slipped Capital Femoral Epiphysis Independent of Obesity Status

BACKGROUND

Slipped capital femoral epiphysis (SCFE) is strongly associated with childhood obesity, yet the prevalence of obesity is orders of magnitude greater than the prevalence of SCFE. Therefore, it is hypothesized that obesity is not, by itself, a sufficient condition for SCFE, but rather one component of a multifactorial process requiring preexisting physeal pathology. Leptin elevation is seen to varying degrees in patients with obesity, and as leptin has been shown to cause physeal pathology similar to the changes seen in SCFE, we propose that leptin may be a factor distinguishing between patients with SCFE and equally obese children without hip abnormalities.

METHODS

Serum leptin levels were obtained from 40 patients with SCFE and 30 control patients with approximate body mass index (BMI) matching. BMI percentiles were calculated according to Centers for Disease Control and Prevention population data by patient age and sex. Patients were compared by demographic characteristics, leptin levels, odds of leptin elevation, and odds of SCFE.

RESULTS

The odds of developing SCFE was increased by an odds ratio of 4.9 (95% confidence interval [CI], 1.31 to 18.48; p < 0.02) in patients with elevated leptin levels, regardless of obesity status, sex, and race. When grouping patients by their obesity status, non-obese patients with SCFE showed elevated median leptin levels at 5.8 ng/mL compared with non-obese controls at 1.7 ng/mL (p = 0.006). Similarly, obese patients with SCFE showed elevated median leptin levels at 17.9 ng/mL compared with equally obese controls at 10.5 ng/mL (p = 0.039). Serum leptin levels increased in association with obesity (p < 0.001), with an increase in leptin of 0.17 ng/mL (95% CI, 0.07 to 0.27 ng/mL) per BMI percentile point.

CONCLUSIONS

To our knowledge, this study is the first to clinically demonstrate an association between elevated serum leptin levels and SCFE, regardless of BMI. This adds to existing literature suggesting that SCFE is a multifactorial process and that leptin levels may have profound physiological effects on the development of various disease states. Despite a strong association with adiposity, leptin levels vary between patients of equal BMI and may be a vital resource in prognostication of future obesity-related comorbidities.

LEVEL OF EVIDENCE

Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Impact of nutritional recovery with linear growth on the concentrations of adipokines in undernourished children living in Brazilian slums

Undernutrition in early life has been reported to be closely associated with the development of non-communicable diseases in adulthood. Adequate treatment is important for reversing these effects. In the present study, we investigated the effects of undernutrition and anthropometric recovery on the weights and heights of children in relation to the concentrations of leptin, adiponectin and plasminogen activator inhibitor-1 (PAI-1). A total of 119 children (aged 6-16 years) from the slums of São Paulo were selected according to their nutritional status and divided into three groups as follows: control (healthy without intervention, n 38) with a height-for-age Z score (HAZ) and a BMI-for-age Z score (BAZ) > -1·6; undernourished (HAZ and/or BAZ < -1·6, n 54); recovered from undernutrition (after treatment in a rehabilitation centre; HAZ and BAZ > -1·6, n 27). Blood samples were collected to determine insulin, glucose, leptin, adiponectin and PAI-1 concentrations. Leptin concentrations in the undernourished group were lower than those in the control and recovered groups (mean 0·92 (95% CI 0·67, 1·25), 2·03 (95% CI 1·46, 2·82) and 1·66 (95% CI 1·15, 2·44) ng/ml, P=0·003), which had similar leptin concentrations. There were no differences in adiponectin and PAI-1 concentrations among the groups. A positive correlation between waist circumference and leptin concentrations was observed in all the girls and boys of the control group (control: r 0·729, P<0·01; undernourished: r 0·490, P<0·05; and recovered: r 0·829, P<0·01; r 0·673, P<0·05). Stronger correlations between leptin and insulin concentrations were observed in the recovered group. The results of the present study indicate that normal leptin concentrations are found when normal height and weight are achieved.

Incretins, amylin and other gut-brain axis hormones in children with coeliac disease

BACKGROUND

Previous research indicated that coeliac disease (CD) is associated with type 1 diabetes mellitus (T1DM). However, the gut-brain axis peptide hormones secretion has not been evaluated so far in patients with CD prior to treatment initiation or under treatment, irrespective of patients having concomitant T1DM or not. The aim of the study was therefore to evaluate these gut hormones at the preprandial levels of patients with CD before and under treatment.

METHODS

Of forty-seven CD children, 12 untreated (UCD), 22 treated with gluten-free diet (TCD) and 13 treated CD with coexisting T1DM (DCD), and 18 healthy controls (HC) were enrolled. Preprandial glucagon-like-peptide-1 (GLP-1), glucose-dependent-insulinotropic-polypeptide (GIP), active amylin, acylated ghrelin (AG), leptin, pancreatic polypeptide (PP) and peptide-tyrosine-tyrosine (PYY) were determined with hormone-map-array technology.

RESULTS

We found in patients with CD compared with HC that the concentration of (i) GLP-1 was reduced remarkably in all patients with CD (P = 0.008), (ii) GIP was lower in patients with UCD (P = 0.008), (iii) amylin was remarkably reduced (P < 0.01) in all patients with CD, (iv) AG was significantly decreased in patients with DCD (P < 0.01), while (v) leptin, PP and PYY were not significantly different. GIP, GLP-1 and amylin levels correlated positively with insulin concentrations (P < 0.001, P = 0.004 and P < 0.01, respectively) in all patients. Amylin and GIP levels were strongly associated with triglycerides concentrations (P < 0.001, for both peptides) in children with CD.

CONCLUSIONS

Our study revealed a different secretion pattern of gut-brain axis hormones in children with CD compared with HC. The alterations in the axis were more pronounced in children with both CD and T1DM.

Nutrition Monitoring in the PICU

The ideal set of variables for nutritional monitoring that may correlate with patient outcomes has not been identified. This is particularly difficult in the PICU patient because many of the standard modes of nutritional monitoring, although well described and available, are fraught with difficulties. Thus, repeated anthropometric and laboratory markers must be jointly analyzed but individually interpreted according to disease and metabolic changes, in order to modify and monitor the nutritional treatment. In addition, isotope techniques are neither clinically feasible nor compatible with the multiple measurements needed to follow progression. On the other hand, indirect alternatives exist but may have pitfalls, of which the clinician must be aware. Risks exist for both overfeeding and underfeeding of PICU patients so that an accurate monitoring of energy expenditure, using targeted indirect calorimetry, is necessary to avoid either extreme. This is very important, since the monitoring of the nutritional status of the critically ill child serves as a guide to early and effective nutritional intervention.

Nutritional status of children with coeliac disease

AIMS

The main aim of this study was to assess the nutritional status of children with newly diagnosed Coeliac disease (CD)with comparison to matched controls. A further aim was to assess relationships between presentation patterns and nutrition in childhood CD.

METHODS

The nutritional status of newly diagnosed CD was assessed by anthropometry, Bioelectrical Impedance and serum leptin levels, and contrasted to age and gender matched controls.

RESULTS

Twenty-five children with CD (mean age of 8.2 +/- 4.5 years) and 25 control children (mean age 8.1 +/- 4.4.) were enrolled. Thirteen (52%) children with CD had gastrointestinal symptoms with 14 having a family history of CD. At presentation 8.7% were wasted, 4.2% were stunted and 20.8% overweight, although none were obese. Mean height and weight for age, other nutritional parameters and serum leptin did not differ between the groups. Serum leptin correlated with BMI in both groups.

CONCLUSIONS

Children with CD more commonly present with atypical symptoms than with classical features. Variations in nutrition (under to overnutrition) may be seen at diagnosis, without relationship to the presence of symptoms. Leptin levels were not altered specifically in the setting of CD. Nutritional assessment remains important in the assessment and management of CD in children.

A meta-analysis of leptin reference ranges in the healthy paediatric prepubertal population

Objective

The initial discovery of leptin (1994) has given rise to a substantial number of published studies. This study aimed at identifying the published data on the reference ranges of total, free and bound leptin concentration in the healthy prepubertal population.

Methods

A search was conducted on original English language studies published from 1994 to 2005 in the following databases: PubMed ( n = 58), EMBASE ( n = 4), Biological Abstracts ( n = 2) and Science Finder Scholar ( n = 66). A cited reference search was completed in Science Citation Index on studies with a leptin range. A meta-analysis was completed on included studies containing a dataset and a sample size for a leptin concentration range and/or mean±standard deviation for a healthy prepubertal population. Preanalytical and analytical variations were examined. Preanalytical variables included aspects such as fasting state and gender, while analytical variation comprised the type of leptin assay methodology.

Results

Twelve studies met the inclusion criteria. One study examined free leptin; 11 studies examined total concentration. No studies reported leptin reference ranges established by Clinical and Laboratory Standards Institute (CLSI) criteria, although four studies reported specific study leptin ranges. The methodology of enzyme-linked immunosorbent assay demonstrated a wider leptin range than radio immunoassay (0.56–36.35 vs. 1.01–12.21 ng/mL). Males had a significantly lower mean leptin concentration than females ( P = 0.0006); obese children had a higher concentration than non-obese ( P = 0.0001).

Conclusion

No studies have established CLSI-based leptin reference ranges in prepubertal healthy children and there is a wide variation in the published leptin concentrations. These differences suggest that caution should be used in the interpretation and comparison between studies.

Serum leptin levels in childhood celiac disease

OBJECTIVE

Leptin has effects on growth and is also involved in immune regulation. We thought that with its intestinal histopathologic alterations due to immune mechanisms, and subsequent malnutrition and/or growth failure, celiac disease (CD) deserves interest regarding leptin status.

METHOD

Serum leptin levels of 19 children with CD on admission and 1 year after gluten-free diet (GFD) and of 16 healthy children were determined.

RESULTS

Mean age was 9.7+/-3.3 years. Mean serum leptin level of children with CD on admission and of healthy children were 1.60+/-0.63 ng/mL, and 3.98+/-1.49 ng/mL, respectively (P: 0.0001). Mean serum leptin level under GFD was 4.55+/-1.97 ng/mL. There was a statistical significant difference between serum levels determined before and 1 year after GFD (P: 0.001) and between those of under GFD and healthy children (P: 0.001). Of 19 patients with CD, 10 (52.6%) showed Marsh IIIc, other 9 (47.4%) showed Marsh IIIa histologic lesions. Mean serum leptin level of children with Marsh IIIc and Marsh IIIa were not different (1.70+/-0.73 ng/mL vs. 1.45+/-0.59 ng/mL). Leptin was correlated with body mass index in healthy children, and in CD both before and after GFD (P<0.001). Mean lumbar z score of the patients on admission and after GFD were 2.7+/-1.3 and 1.9+/-0.8, respectively (P: 0.048). Serum leptin level was not correlated with lumbar z score either before or after GFD.

CONCLUSIONS

Serum leptin level is affected in childhood CD, it is not directly related to histopathologic findings, and is responsive to GFD. Further studies investigating its level in different clinical and histopathologic presentations might give clear clues about the role of leptin in CD.