Plasma total adiponectin levels in pediatrics: reference intervals calculated as a continuous variable of age

Adiponectin levels in Brazilian adolescents: Distribution and associated factors in ERICA survey

BACKGROUND

The aim of this study was to evaluate the distribution of adiponectin and associated factors with low adiponectin levels in a large sample of adolescents from different Brazilian regions.

METHODS

This is a national, school-based, cross-sectional multicenter study of cardiovascular risk factors in Brazilian adolescents aged 12 to 17 years. Serum adiponectin levels (μg/ml) were measured by enzyme-linked immunosorbent assay kit. Given the lack of reference values, sex-and age-specific median was adopted as the cutoff point, with the values below the median representing a higher-risk profile. Associated factors with low levels of adiponectin were investigated using Poisson regression.

RESULTS

The sample consisted of 4546 adolescents, the majority female (61.2%). The prevalence of overweight/obesity and abdominal obesity was 30% and 13.4%, respectively. The medians of adiponectin were 13.4 μg/ml (95%CI: 12.8-14.0) in males and 14.2 μg/ml (95%CI: 13.3-15.0) in females. Lower adiponectin levels were associated with both overweight (Prevalence Ratios (PR) = 1.17; 95%CI 1.01-1.36) and obesity (PR = 1.36; 95%CI 1.16-1.56) in males, while, in females, adiponectin levels were associated only with obesity (PR = 1.45; 95% CI 1.26-1.66). Increased waist circumference in both males and females was inversely associated with adiponectin level.

CONCLUSIONS

Adiponectin levels were lower among adolescents with weight excess and abdominal obesity. Male adolescents who live in rural areas and study at private schools also showed lower adiponectin concentrations.

National and international initiatives and approaches for the establishment of reference intervals in pediatric laboratory medicine

Thoroughly validated laboratory medicine reference intervals for children of all ages groups have been published increasingly during the last years. The aim of this review is to present a number of these studies and the various approaches to the generation of reference intervals. Population-based data obtained in large cohorts of healthy children in Germany, Northern Europe, North America, and selected other countries as well as patient-derived data collected in many areas of the world are discussed. Additionally, special research aspects such as reference intervals for preterm neonates, preanalytical issues, intraindividual variation of analytes, or follow-up studies that are covered in many of these studies are presented.

Soluble mediators regulating immunity in early life

Soluble factors in blood plasma have a substantial impact on both the innate and adaptive immune responses. The complement system, antibodies, and anti-microbial proteins and peptides can directly interact with potential pathogens, protecting against systemic infection. Levels of these innate effector proteins are generally lower in neonatal circulation at term delivery than in adults, and lower still at preterm delivery. The extracellular environment also has a critical influence on immune cell maturation, activation, and effector functions, and many of the factors in plasma, including hormones, vitamins, and purines, have been shown to influence these processes for leukocytes of both the innate and adaptive immune systems. The ontogeny of plasma factors can be viewed in the context of a lower effectiveness of immune responses to infection and immunization in early life, which may be influenced by the striking neonatal deficiency of complement system proteins or enhanced neonatal production of the anti-inflammatory cytokine IL-10, among other ontogenic differences. Accordingly, we survey here a number of soluble mediators in plasma for which age-dependent differences in abundance may influence the ontogeny of immune function, particularly direct innate interaction and skewing of adaptive lymphocyte activity in response to infectious microorganisms and adjuvanted vaccines.

Somatic mosaicism for the p.His1047Arg mutation in PIK3CA in a girl with mesenteric lipomatosis

We describe a patient who presented with a localized growth of mature fat tissue, which was surgically removed. MRI imaging identified diffuse increase in visceral adipose tissue. Targeted deep sequencing of the resected tissue uncovered a p.H1047R variant in PIK3CA, which was absent in blood. This report expands the phenotypic spectrum of mosaic PIK3CA mutations.

Urinary homovanillic and vanillylmandelic acid in the diagnosis of neuroblastoma: report from the Italian Cooperative Group for Neuroblastoma

BACKGROUND

Urinary homovanillic and vanillylmandelic acid (HVA and VMA) are well known biomarkers for the management of neuroblastoma (NB). Very few and contradictory publications on their diagnostic performance are present in the literature. The aim of this study is to review the results of HVA/Cr and VMA/Cr obtained by the reference laboratory of the Italian Cooperative Group for NB within a 7-year period using HPLC-EC.

PROCEDURE

Updated reference intervals based on age as a continuous variable were calculated by using a multivariate statistical analysis. The diagnostic performance of the two biomarkers has been established by calculating their specificity and sensitivity and by receiver operating characteristics (ROC) curves for different ages and stages of disease.

RESULTS

Accurate age-related reference intervals were obtained from 648 HVA/Cr and 671 VMA/Cr results derived from patients in which the diagnosis of neuroendocrine tumors was excluded. Sensitivity, specificity and ROC curves were obtained from 169 HVA/Cr and 179 VMA/Cr results from confirmed NB patients. The best diagnostic performance was obtained in stage 4S tumors and in children <18months.

CONCLUSIONS

This is the first report, to our knowledge, that analyzes in depth the diagnostic performance of HVA/Cr and VMA/Cr for NB in different stages and age subgroups. In addition, the present work provides cut-off points able to discriminate between NB patients and negative subjects suspected to have NB and could be of help in taking medical decisions.