Dysregulation of mitochondrial function and biogenesis modulators in adipose tissue of obese children.

BACKGROUND/OBJECTIVES: We aimed to evaluate mitochondrial biogenesis (MB), structure, metabolism and dysfunction in abdominal adipose tissue from male pediatric patients with obesity. SUBJECTS/METHODS: Samples were collected from five children with obesity (percentile ⩾95) and five eutrophic boys (percentile ⩾5/⩽85) (8-12 years old) following parental informed consent. We analyzed the expression of key genes involved in MB (sirtuin-1 (SIRT1), peroxisome proliferator-activated receptor-γ (PPARγ), PPARγ coactivator-1α (PGC1α), nuclear respiratory factors 1 and 2 (NRF1, NRF2) and mitochondrial transcription factor A (TFAM) and surrogates for mitochondrial function/structure/metabolism (porin, TOMM20, complex I and V, UCP1, UCP2, SIRT3, SOD2) by western blot. Citrate synthase (CS), complex I (CI) activity, adenosine triphosphate (ATP) levels, mitochondrial DNA (mtDNA) content and oxidative stress end points were also determined. RESULTS: Most MB proteins were significantly decreased in samples from children with obesity except complex I, V and superoxide dismutase-2 (SOD2). Similarly, CS and CI activity showed a significant reduction, as well as ATP levels and mtDNA content. PPARγ, PGC1α, complex I and V and SOD2 were hyperacetylated compared with lean samples. Concurrently, in samples from children with obesity, we found decreased SOD2 activity and redox state imbalance highlighted by decreased reduced glutathione/oxidized glutathione (GSH/GSSG) ratio and significant increases in protein carbonylation. CONCLUSIONS: Adipose tissue from children with obesity demonstrates a dysregulation of key modulators of MB and organelle structure, and displays hyperacetylation of key proteins and altered expression of upstream regulators of cell metabolism.

Breastfeeding's protection against illness-induced anorexia is mediated partially by docosahexaenoic acid.

OBJECTIVE: To test whether breastfeeding's protection against anorectic responses to infection is mediated by n-3 fatty acids' attenuation of interleukin (IL)-1beta and tumor necrosis factor (TNF)alpha. DESIGN: Experimental and observational studies. SETTING: A hospital-based study was conducted. SUBJECTS: Five groups of infants were followed; three in the experimental and two in the observational study. METHODS: Breast-fed- (BF-1), DHA-supplemented formula- (SFF-1), and non-DHA-supplemented formula-fed (FF-1) infants were studied before and after immunization against diphtheria, tetanus, pertussis and haemophilus influenzae type b. Pre- and post-immunization energy intakes (EI) and serum IL-1beta and TNFalpha were measured. The two other groups, breast-fed (BF-2) and formula-fed (FF-2) infants with pneumonia were followed throughout hospitalization. EI, IL-1beta and TNFalpha were measured at admission and discharge. Baseline erythrocyte fatty acid contents were determined. RESULTS: Both cytokines increased following immunization in all feeding groups. Post-immunization reductions in EI of SFF-1 infants (-11.8+/-5%, CI(95)=-23.3, 1.4%, P=0.07) were intermediate to those observed in BF-1 (-5.2+/-4.2%, CI(95)=-15.2, 5.9%, P=0.27) and FF-1 infants (-18+/-4.4%, CI(95)=-29%, -5.4%, P=0.02). In the observational study, TNFalpha (17.2+/-8.3 vs 3.4+/-3.0 ng/l, P=0.001) and decreases in EI (-31+/-43 vs -15+/-31%, CI(95)=-34%, 0.001%, P=0.056) were greater in FF-2 than in BF-2 infants at admission. Breastfeeding duration was associated positively with docosahexaenoic acid (DHA) erythrocyte contents, and negatively with admission TNFalpha. Decreases in EIs were associated with IL-1beta and TNFalpha concentrations. CONCLUSION: Reductions in EI following immunologic or infectious stimuli were associated with increases in IL-1beta and TNFalpha. Those reductions were attenuated by breastfeeding, and mediated in part by tissue DHA.