ESPE Abstracts

Childhood obesity has increased in epidemic proportions worldwide. Complications of obesity represent a growing proportion of childhood morbidity. Albuminuria resulting from endothelial damage was recognized as a complication of obesity, implying higher cardiovascular risk.

Aim: to investigate the association of albuminuria in obese children with metabolic and inflammatory parameters.

Materials and Methods: The study included 29 healthy controls (HC, 14 M, age 15.46+/-1.51 years, BMI-z 0.1 SD (IQR -0.68 – 0.55) ) and 34 obese children (OB; 19 M, age 14,69+/-1.60 years, BMI-z 2.35 SD (IQR 2.16 – 2.52)). Albuminuria was reported as the mean of albumin to creatinine ratio (ACR) from two first-morning urine samples. It was correlated with clinical parameters, parameters of metabolic complications (HOMA-IR, ALT, lipid profile), and inflammation (CRP and fibrinogen, chemokine/chemokine receptors). B-cell (CD19+), T-cell (CD3+), and monocyte (CD14+) phenotype and CCR2, CCR4, CXCR3, and CXCR4 expression was determined from peripheral blood mononuclear cells using flow cytometry. Chemokines CCL2, CCL5, and CXCL10 were determined using BioLegend LEGENDplex™, and CXCL12 was analyzed by ELISA. Results are reported as the median and interquartile range (IQR).

Results: Obese children had higher ACR than lean controls (ACR (OB) 0.5 mg/mmol (IQR 0.275 – 0.8) v.s. ACR (HC) 0.2 mg/mmol (IQR 0.0-0.4), P=0.0035), and higher inflammatory markers (CRP(OB) 2.2 mg/L (IQR 1.0 - 4.1) v.s. CRP(HC) 0.1 mg/L (IQR 0.1 – 0.5), P<0,001; fibrinogen (OB) 3.4 g/L (IQR 2.9-4.0) v.s. fibrinogen (HC) 2.6 g/L (IQR 2.3 – 2.9), P<0,001). In all subjects included, ACR positively correlated with BMI-SDS, insulin concentration, HOMA-IR, and diastolic blood pressure (DBP). However, no correlations with metabolic or inflammatory markers were found in the obese group. Obese subjects showed a positive correlation of ACR with monocyte proportion, and an inverse association with monocytes expressing CCR2, CCR5 CXCR3, and CXCR4, but no correlations with chemokine ligands. In healthy subjects, ACR positively correlated with all CCR2-expressing lymphocyte subsets and ligand CXCL10 but reversely with CCL5.

Conclusion: Obese children had a higher rate of albumin excretion and inflammatory markers, but no associations of ACR with metabolic and inflammatory markers. When all subgroups were included, ACR showed a significant positive correlation with the degree of obesity, insulin resistance markers, and DBP. However, there are significant associations of ACR with monocyte subsets suggesting a monocyte role in renal endothelial damage. Albuminuria might be a complication of obesity observed even at a young age, associated with particular chemokine network activation.