Longer duration of obesity is associated with a reduction in urinary angiotensinogen in prepubertal children.
BACKGROUND
We aimed to study the impact of obesity on urinary excretion of angiotensinogen (U-AGT) in prepubertal children, focusing on the duration of obesity and gender. Also, we aimed to evaluate whether plasma angiotensinogen (P-AGT) and hydrogen peroxide (H2O2) play a role in the putative association.


METHODS
Cross-sectional evaluation of 305 children aged 8-9 years (160 normal weight, 86 overweight, and 59 obese). Anthropometric measurements and 24-h ambulatory blood pressure monitoring were performed. Angiotensinogen (AGT) was determined by a commercial enzyme-linked immunosorbent assay (ELISA) kit and H2O2by a microplate fluorometric assay.


RESULTS
U-AGT and P-AGT levels were similar across body mass index (BMI) groups and between sexes. However, boys who were overweight/obese since the age of 4 years presented lower levels of U-AGT compared with those of normal weight at the same age. In children who were overweight/obese since the age of 4, urinary H2O2decreased with P-AGT.


CONCLUSIONS
A higher duration of obesity was associated with decreased U-AGT in boys, thus reflecting decreased intrarenal activity of the renin-angiotensin system. Also, children with a longer duration of obesity showed an inverse association between urinary H2O2and P-AGT. Future studies should address whether these results reflect an early compensatory mechanism to limit obesity-triggered renal dysfunction.
Department of Pharmacology and Therapeutics, Faculty of Medicine of University of Porto, Porto, Portugal. mmorato@ff.up.pt.|Department of Drug Sciences, Laboratory of Pharmacology, Faculty of Pharmacy of the University of Porto, Rua Jorge Viterbo Ferreira, 228, 4050-313, Porto, Portugal. mmorato@ff.up.pt.|MedInUP - Center for Drug Discovery and Innovative Medicines, University of Porto, Porto, Portugal. mmorato@ff.up.pt.|Laboratory of Pharmacology, Department of Drug Sciences, Faculty of Pharmacy of University of Porto, Porto, Portugal. mmorato@ff.up.pt.
Manuela
http://orcid.org/0000-0002-9509-0613
M
Morato
EPIUnit - Institute of Public Health, University of Porto, Porto, Portugal.|Division of Pediatric Nephrology, Integrated Pediatric Hospital, Centro Hospitalar São João, Porto, Portugal.|Department of Pediatrics, Faculty of Medicine of University of Porto, Porto, Portugal.
Liane
L
Correia-Costa
Department of Pharmacology and Therapeutics, Faculty of Medicine of University of Porto, Porto, Portugal.|MedInUP - Center for Drug Discovery and Innovative Medicines, University of Porto, Porto, Portugal.
Teresa
T
Sousa
Department of Pharmacology and Therapeutics, Faculty of Medicine of University of Porto, Porto, Portugal.|EPIUnit - Institute of Public Health, University of Porto, Porto, Portugal.
Dina
D
Cosme
Division of Pediatric Nephrology, Center for Pediatrics and Adolescent Medicine, University of Heidelberg, Heidelberg, Germany.
Franz
F
Schaefer
Division of Pediatric Cardiology, Integrated Pediatric Hospital, Centro Hospitalar São João, Porto, Portugal.
José Carlos
JC
Areias
Department of Pediatrics, Faculty of Medicine of University of Porto, Porto, Portugal.|Division of Pediatric Nutrition, Integrated Pediatric Hospital, Centro Hospitalar São João, Porto, Portugal.|CINTESIS - Center for Research in Health Technologies and Information Systems, Faculty of Medicine, University of Porto, Porto, Portugal.
António
A
Guerra
EPIUnit - Institute of Public Health, University of Porto, Porto, Portugal.|Division of Pediatric Nephrology, Integrated Pediatric Hospital, Centro Hospitalar São João, Porto, Portugal.|Department of Pediatrics, Faculty of Medicine of University of Porto, Porto, Portugal.
Alberto Caldas
AC
Afonso
EPIUnit - Institute of Public Health, University of Porto, Porto, Portugal.|Department of Clinical Epidemiology, Predictive Medicine and Public Health, Faculty of Medicine of University of Porto, Porto, Portugal.
Henrique
H
Barros
EPIUnit - Institute of Public Health, University of Porto, Porto, Portugal.|Department of Clinical Epidemiology, Predictive Medicine and Public Health, Faculty of Medicine of University of Porto, Porto, Portugal.
Ana
A
Azevedo
Department of Pharmacology and Therapeutics, Faculty of Medicine of University of Porto, Porto, Portugal.|MedInUP - Center for Drug Discovery and Innovative Medicines, University of Porto, Porto, Portugal.
António
A
Albino-Teixeira
D000273:Adipose Tissue / Q000378:metabolism; D000808:Angiotensinogen / Q000097:blood / Q000652:urine*; D018660:Blood Pressure Monitoring, Ambulatory; D015992:Body Mass Index; D002648:Child; D003430:Cross-Sectional Studies; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D006861:Hydrogen Peroxide / Q000652:urine*; D007668:Kidney / Q000378:metabolism / Q000503:physiopathology*; D008297:Male; D009765:Obesity / Q000652:urine*; D065667:Renal Elimination; D012084:Renin-Angiotensin System; D012737:Sex Factors; D013997:Time Factors
D000808:Angiotensinogen; D006861:Hydrogen Peroxide
Angiotensinogen; Body mass index; Children; Hydrogen peroxide; Obesity; Overweight