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BACKGROUND: Accelerated catch-up growth following intrauterine restriction increases the risk of developing visceral adiposity and metabolic abnormalities. However, the underlying molecular mechanisms of such metabolic programming are still poorly understood. METHODS: A Wistar rat model of catch-up growth following intrauterine restriction was used. A gene expression array was performed in the retroperitoneal adipose tissue sampled at postnatal day (PD) 42. RESULTS: Five hundred and forty-six differentially expressed genes (DEGs) were identified (adjusted p value < 0.05). Gene ontology enrichment analysis identified pathways related to immune and lipid metabolic processes, brown fat cell differentiation, and regulation of PI3K. Ccl21, Npr3, Serpina3n, Pnpla3, Slc2a4, and Serpina12 were validated to be upregulated in catch-up pups (all p < 0.01) and related to several fat expansion and metabolic parameters, including body weight at PD42, postnatal body weight gain, white and brown adipose tissue mass, plasma triglycerides, and insulin resistance index (all p < 0.05). CONCLUSIONS: Genes related to immune and metabolic processes were upregulated in retroperitoneal adipose tissue following catch-up growth in juvenile rats and were found to be associated with fat expansion and metabolic parameters. Our results provide evidence for several dysregulated genes in white adipose tissue that could help develop novel strategies to prevent the metabolic abnormalities associated with catch-up growth. IMPACT: Catch-up growth presents several dysregulated genes in white adipose tissue related to metabolic abnormalities. Ccl21, Npr3, Serpina3n, Pnpla3, Slc2a4, and Serpina12 were validated to be upregulated in catch-up pups and related to visceral fat expansion and metabolic parameters. Profiling and validation of these dysregulated genes in visceral adipose tissue could help develop novel strategies to prevent the metabolic abnormalities associated with catch-up growth.

BACKGROUND: Low birth weight (LBW) followed by a rapid postnatal catch-up in weight predisposes individuals to a central distribution of body fat, which is reverted by metformin. Growth-and-differentiation-factor-15 (GDF15) plays an important role in the regulation of energy homeostasis, reducing food intake and body weight. We assessed whether GDF15 concentrations are raised by long-term metformin treatment in LBW/catch-up girls with precocious pubarche (PP, pubic hair

OBJECTIVES: Maternal overfeeding during gestation may lead to adverse metabolic programming in the offspring mediated by epigenetic alterations. Potential reversal, in early life, of these alterations may help in the prevention of future cardio-metabolic conditions. In this context, our aims were: (1) to study the effects of maternal overfeeding on the metabolic and epigenetic programming of offspring's adipose tissue; and (2) to test the potential of postnatal metformin treatment to reverse these changes. METHODS: We used a swine animal model where commercial production sows were either overfed or kept under standard diet during gestation, and piglets at birth were randomly assigned to metformin (n = 16 per group) or vehicle treatment during lactation (n = 16 per group). RESULTS: Piglets born to overfed sows showed a worse metabolic profile (higher weight, weight gain from birth and abdominal circumference; all p < 0.05) together with altered serological markers (increased HOMA-IR, fructosamine, total cholesterol, C-Reactive Protein and lower HMW adiponectin; all p < 0.05). The visceral adipose tissue also showed altered morphology (increased adipocyte area, perimeter and diameter; all p < 0.05), as well as changes in gene expression (higher CCL2 and INSR, lower DLK1; all p < 0.05), and in DNA methylation (96 hypermethylated and 99 hypomethylated CpG sites; FDR < 0.05). Metformin treatment significantly ameliorated the abnormal metabolic profile, decreasing piglets' weight, weight gain from birth, abdominal circumference and fructosamine (all p < 0.05) and reduced adipocyte area, perimeter, and diameter in visceral adipose tissue (all p < 0.05). In addition, metformin treatment potentiated several associations between gene expression in visceral adipose tissue and the altered metabolic markers. CONCLUSIONS: Maternal overfeeding during gestation leads to metabolic abnormalities in the offspring, including adipose tissue alterations. Early metformin treatment mitigates these effects and could help rescue the offspring's metabolic health.

Both the innate and adaptive immune responses are deregulated in individuals with obesity and are key drivers of its associated metabolic alterations. Although the anti-inflammatory growth differentiation factor 15 (GDF-15) is a candidate protein against obesity, its mechanisms regulating the immune responses are not fully cleared. We examined whether GDF-15 was related to serum immunoglobulins in a children's cohort assessed longitudinally during childhood. Results showed that circulating GDF-15 positively associated with IgA (p < 0.002) and IgG (p < 0.001) levels and the IgA*IgG product (p < 0.001) in apparently healthy children at both baseline (age 9) and follow-up (age 13). The associations were readily observed in heavier children (those with BMI-SDS above the median) as well as in children with higher renal fat accumulation (those with renal fat-to-height ratio above the median) and remained significant after correcting for possible confounding variables. Serum GDF-15 levels accounted for up to 16% of the variance of follow-up IgG levels and up to 14% of the variance of follow-up IgA*IgG product. The longitudinal associations of the anti-inflammatory GDF-15 with IgA, IgG and the IgA*IgG product in children with higher BMI or higher renal fat accumulation suggest a role of GDF-15 in human obesity through the regulation of the immune adaptive system.

BACKGROUND: Children with low birth weight (LBW) have a higher risk of developing endocrine-metabolic disorders later in life. Deregulation of specific microRNAs (miRNAs) could underscore the programming of adult pathologies. We analyzed the miRNA expression pattern in both umbilical cord serum samples from LBW and appropriate-for-gestational-age (AGA) newborns and maternal serum samples in the 3rd trimester of gestation, and delineated the relationships with fetal growth, body composition, and markers of metabolic risk. METHODS: Serum samples of 12 selected mother-newborn pairs, including 6 LBW and 6 AGA newborns, were used for assessing miRNA profile by RNA-sequencing. The miRNAs with differential expression were validated in a larger cohort [49 maternal samples and 49 umbilical cord samples (24 LBW, 25 AGA)] by RT-qPCR. Anthropometric, endocrine-metabolic markers and body composition (by DXA) in infants were determined longitudinally over 12 months. RESULTS: LBW newborns presented reduced circulating concentrations of miR-191-3p (P = 0.015). miR-191-3p levels reliably differentiated LBW from AGA individuals (ROC AUC = 0.76) and were positively associated with anthropometric and body composition measures at birth and weight Z-score at 12 months (P < 0.05). CONCLUSIONS: miR-191-3p was reliably different in LBW individuals, and could be a new player in the epigenetic mechanisms linking LBW and future endocrine-metabolic adverse outcomes. IMPACT: Children with low birth weight (LBW) have a higher risk of developing endocrine-metabolic disorders. Deregulation of specific microRNAs (miRNAs) could underscore the programming of those pathologies. miR-191-3p is downregulated in serum of LBW newborns, and its concentrations associate positively with neonatal anthropometric measures, with lean mass and bone accretion at age 15 days and with weight Z-score at age 12 months. miR-191-3p was reliably different in individuals with LBW, and could be a new player in the epigenetic mechanisms connecting LBW and future endocrine-metabolic adverse outcomes.

BACKGROUND: Metformin treatment (1000-2000 mg/day) over 6 months in pubertal children and/or adolescents with obesity and hyperinsulinism is associated with a reduction in body mass index (BMI) and the insulin resistance index (HOMA-IR). We aimed to ascertain if long-term treatment (24 months) with lower doses of metformin (850 mg/day) normalizes the endocrine-metabolic abnormalities, improves body composition, and reduces the carotid intima-media thickness (cIMT) in pre-puberal and early pubertal children with obesity. METHODS: A pilot double-blind, placebo-controlled trial was conducted on 18 pre-puberal and early pubertal (Tanner stage I-II) children with obesity and risk markers for metabolic syndrome. Patients were randomly assigned (1:1) to receive metformin (850 mg/day) or placebo for 24 months. Clinical, biochemical (insulin, lipids, leptin, and high-sensitivity C-reactive protein [hsCRP]), and imaging (body composition [dual-energy X-ray absorptiometry and magnetic resonance imaging]) parameters as well as cIMT (ultrasonography) were assessed at baseline and at 6, 12, and 24 months. RESULTS: The 12-month treatment tend to cause a reduction in weight standard deviation scores (SDS), BMI-SDS, leptin, leptin-to-high-molecular-weight (HMW) adiponectin ratio, hsCRP, cIMT, fat mass, and liver fat in metformin-treated children compared with placebo. The effect of metformin on the reduction of BMI-SDS, leptin, leptin-to-HMW adiponectin ratio, hsCRP, and liver fat seemed to be maintained after completing the 24 months of treatment. No changes in insulin sensitivity (HOMA-IR) or adverse effects were detected. CONCLUSION: In this pilot study, metformin treatment in pre-puberal and early pubertal children with obesity seemed to improve body composition and inflammation markers. Our data encourage the development of future fully powered trials using 850 mg/day metformin in young children, highlighting its excellent tolerance and potential long-term benefits.