Prepubertal Obesity Research Articles

Pre-pubertal obesity compromises ovarian oxidative stress, DNA repair and chemical biotransformation

Obesity in adult females impairs fertility by altering oxidative stress, DNA repair and chemical biotransformation. Whether prepubertal obesity results in similar ovarian impacts is under-explored. The objective of this study was to induce obesity in prepubertal female mice and assess puberty onset, follicle number, and abundance of oxidative stress, DNA repair and chemical biotransformation proteins basally and in response to 7,12-dimethylbenz(a)anthracene (DMBA) exposure. DMBA is a polycyclic aromatic hydrocarbon that has been shown to be ovotoxic. Lactating dams (C57BL6J) were fed either a normal rodent containing 3.5% kCal from fat (lean), or a high fat diet comprised of 60% kCal from fat, and 9% kCal from sucrose. The offspring were weaned onto the diet of their dam and exposed at postnatal day 35 to either corn oil or DMBA (1 mg/kg) for 7 d via intraperitoneal injection. Mice on the HFD had reduced (P < 0.05) age at puberty onset as measured by vaginal opening but DMBA did not impact puberty onset. Heart, spleen, kidney, uterus and ovary weight were increased (P < 0.05) by obesity and liver weight was increased (P < 0.05) by DMBA exposure in obese mice. Follicle number was largely unaffected by obesity or DMBA exposure, with the exception of primary follicle number, which were higher (P < 0.05) in lean DMBA exposed and obese control relative to lean control mice. There were also greater numbers (P < 0.05) of corpora lutea in obese relative to lean mice. In lean mice, DMBA exposure reduced (P < 0.05) the level of CYP2E1, EPHX1, GSTP1, BRCA1, and CAT but this DMBA-induced reduction was absent in obese mice. Basally, obesity reduced (P < 0.05) the abundance of CYP2E1, EPHX1, GSTP1, BRCA1, SOD1 and CAT. There was greater (P < 0.05) fibrotic staining in obese DMBA-exposed ovaries and PPP2CA was decreased (P < 0.05) in growing follicles by both obesity and DMBA exposure. Thus, prepubertal obesity alters the capacity of the ovary to respond to DNA damage, ovotoxicant exposure and oxidative stress.

Time restricted feeding improves insulin resistance and reduces progressive proteinuria in young obese Dahl salt-sensitive rats prior to puberty

Prepubertal obesity (PPO) is now associated with early signs of renal disease. An improper eating behavior is one of the leading causes of PPO. Time restricted feeding (TRF) has been shown to be beneficial in obese patients without reducing body weight. However, the effects of TRF on renal injury during PPO have not been investigated. Therefore, the current study examined whether TRF reduces renal injury in obese Dahl salt-sensitive leptin receptor mutant (SSLepRmutant) rats before puberty. Four-week-old SS and SSLepRmutant rats were given either ad libitum access to food for 24 hrs (control) or 8 hrs during their active phase (TRF) for 4 weeks. Body weight and food intake were significantly higher in SSLepRmutant rats versus SS rats throughout the study, and TRF did not have an impact on both parameters. Fasting blood glucose levels were similar in all groups (≤120 mg/dL). Fasting plasma insulin levels were significantly higher in SSLepRmutant rats vs SS rats (5±1 vs. 1.0±0.1 ng/mL; p&lt;0.05), and TRF reduced fasting plasma insulin by 70% in SSLepRmutant rats. Moreover, TRF markedly improved insulin resistance in SSLepRmutant rats. At the end of the study, we did not observe any differences in MAP (via carotid catheter) among the groups. Proteinuria was significantly higher in SSLepRmutant vs SS rats (361±32 vs. 17±4 mg/day; p&lt;0.05), and TRF only reduced proteinuria in SSLepRmutant rats (144±19 mg/day; p&lt;0.05). We observed a significant increase in GFR (via creatinine clearance) in SSLepRmutant rats compared to SS rats (0.71±0.08 vs. 0.39±0.07 mL/min/gkwt; p&lt;0.05), and TRF normalized GFR in SSLepRmutant rats (0.37±0.07 mL/min/gkwt; p&lt;0.05). Glomerular injury and renal fibrosis were markedly elevated in SSLepRmutant vs SS rats, and TRF improved these histological changes. Overall, these data suggest that TRF prevents the early progression of proteinuria by possibly reducing the insulin resistant effects on GFR during PPO. NIDDK (DK109133) and AG (AG057842). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Kidney disease associated with pre-pubertal obesity initiates pathological alterations in the brain of Dahl salt-sensitive rats

Childhood/pre-pubertal obesity (PPO) is implicated in the development of chronic kidney disease (CKD), and there is evidence that PPO also increases the risk of developing Alzheimer disease (AD) later in life. In the current study, we aim to investigate the correlation between CKD and the development of AD-like pathology in a rat model of CKD associated with PPO. We hypothesize that systemic inflammation due to PPO exacerbates CKD and induces AD-like pathology in the brain at older age. In our preliminary studies, we utilized the Dahl salt sensitive leptin receptor mutant rat (SSLepRmutant), which is a novel model of PPO. 6-week-old Dahl salt-sensitive (SS) (control, n=3) and SSLepRmutant rats (n=5) were monitored for proteinuria every 3 weeks, for a 12-week period. Throughout the study, we observed significantly elevated proteinuria in SSLepRmutant rats (Week-6: 337±81 mg/day, Week-9: 371±147 mg/day, Week-18: 1920±318 mg/day) compared to SS rats (Week-6: 25±7 mg/day, Week-9: 35±39 mg/day, Week-18: 35±33 mg/day). At 18-week, creatinine levels were significantly higher in SSLepRmutant rats (1.5±0.5 mg/dL) versus SS rats (0.4±0.03 mg/dL) indicating CKD. Additionally, we found significant elevation of triglycerides in SSLepRmutant rats (5134±1211 mg/dL) compared to SS rats (79±21 mg/dL). To investigate the brain pathology, we performed immunochemical analysis (dot-blot assay) using A11 antibody to determine the levels of Amyloid-beta oligomers (Aβo). Our results show that there was tendency for Aβo levels to be increased in the brains from obese SSLepRmutant rats compared to SS. Finally, we tested the permeability of the blood-brain barrier to Evans blue dye and observed that the brain of SSLepRmutant rats was more permeable to the dye compared to SS rats as early as 8 weeks of age. Overall, these results indicate that PPO obesity not only increases the susceptibility to develop CKD but also causes Alzheimer-like pathology during the prepubescent stage. NIDDK (DK109133) and AG (AG057842) awarded to Jan M. Williams. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Pre-Weaning Overfeeding Promotes Prepubertal Obesity and Evokes Sexual Dysfunction in Young Adult Rats

Obesity in early life can contribute to several health issues in adulthood, including diabetes, high blood pressure, and high cholesterol, and these conditions are associated with sexual dysfunction. Here, we hypothesized that pre-weaning overfeeding can have long lasting effects on body fat distribution and erectile function that will be observed in young adult males. On postnatal day (PND 1), Wistar rats were separated into two groups: normal litter (NL) with 10 pups per dam, or small litter (SL) with 3 pups per dam. Male rats (n = 8-10 per group) were then assessed at two different time points: during the prepubertal stage (PND 40) and in adulthood (PND 120). Erectile function was assessed only after sexual maturation (i.e., PND 120). Body weight, retroperitoneal and perigonadal adipose tissue (fat pad weight/100g of the body) were evaluated. Following euthanasia at PND 120, the corpus cavernosum (CC) was removed to perform functional studies using a strip myograph. Contractile and relaxation responses were evaluated by electrical field stimulation (EFS) and concentration-response curves (CRC) to phenylephrine [Phe, 1nM-30μM, millinewton (mN)] or acetylcholine (Ach 1nM-30μM, % relaxation) were performed. At the prepubertal stage, SL rats had higher body weight (NL 149±3 vs. SL 186±5, g, p&lt;0.05), and increased retroperitoneal (NL 0.17±0.01 vs. SL 0.32±0.03, g/100g, p&lt;0.05) and perigonadal (NL 0.38± 0.02 vs. SL 0.45±0.03, g/100g, p&lt;0.05) adipose tissue. At PND 120, SL group presented increased body weight (NL 534.2.7±13 vs. SL 631.6±10, g, p&lt;0.05), retroperitoneal (NL 1.31±0.11 vs. SL 1.82±0.14, g/100g, p&lt;0.05) and perigonadal (NL 1.74±0.10 vs. SL 2.18±0.15, g/100g, p&lt;0.05) adipose tissue when compared with NL group. The CC of SL rats at PND 120 had increased contraction induced by EFS for all frequencies (1 Hz: NL 0.5 ± 0.2 mN vs. SL 0.9 ± 0.2 mN; 4 Hz: NL 1.2 ± 0.3 mN vs. SL 1.8 ± 0.2 mN; 16 Hz: NL 1.9 ± 0.4 mN vs. SL 3 ± 0.4 mN), whereas the relaxation was decreased in SL (1 Hz: NL 0.77 ± 0.18% vs. SL 0.27 ± 0.09%; 4 Hz: NL 2.48 ± 0.26% vs. SL 1.36 ± 0.41%; 16 Hz: NL 3.06 ± 0.28% vs. SL 2.39 ± 0.53%). CRC showed increased contractile response to Phe (Emax NL 2.3±0.3 vs. SL 3.8± 0.6, mN, p=0.05) and reduced potency of ACh (pEC50 NL 6.4±0.6 vs. SL 4.9±0.7, mN, p=0.1) in the CC of SL. Incubation with indomethacin (10μM) abolished the differences in the contractile response induced by EFS or Phe between SL and NL, suggesting a heightened inflammatory response. Moreover, the CC of SL rats presented increased expression of Phospho-p44/42 MAPK (NL 0.9±0.25 vs. SL 1.3±0.11, p=0.2). Finally, proteome profiler cytokine array of serum samples from SL animals showed increased circulating levels of cytokines and chemokines associated with obesity, aging, and vascular dysfunction. Together, these data suggest that early prepubertal obesity has long-lasting negative implications on sexual function in young adulthood. National Institutes of Health (NIH); American Heart Association (AHA); Fulbright Program. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Metformin reduces insulin resistance and attenuates progressive renal injury in prepubertal obese Dahl salt-sensitive rats.

Prepubertal obesity is currently an epidemic and is considered as a major risk factor for renal injury. Previous studies have demonstrated that insulin resistance contributes to renal injury in obesity, independent of diabetes. However, studies examining the relationship between insulin resistance and renal injury in obese children are lacking. Recently, we reported that progressive renal injury in Dahl salt-sensitive (SS) leptin receptor mutant (SSLepRmutant) rats was associated with insulin resistance before puberty. Therefore, the aim of the present study was to examine whether decreasing insulin resistance with metformin will reduce renal injury in SSLepRmutant rats. Four-wk-old SS and SSLepRmutant rats were separated into the following two groups: 1) vehicle and 2) metformin (300 mg/kg/day) via chow diet for 4 wk. Chronic administration of metformin markedly reduced insulin resistance and dyslipidemia in SSLepRmutant rats. We did not detect any differences in mean arterial pressure between vehicle and metformin-treated SS and SSLepRmutant rats. Proteinuria was significantly greater in SSLepRmutant rats versus SS rats throughout the study, and metformin administration significantly reduced proteinuria in SSLepRmutant rats. At the end of the protocol, metformin prevented the renal hyperfiltration observed in SSLepRmutant rats versus SS rats. Glomerular and tubular injury and renal inflammation and fibrosis were significantly higher in vehicle-treated SSLepRmutant rats versus SS rats, and metformin reduced these parameters in SSLepRmutant rats. These data suggest that reducing insulin resistance with metformin prevents renal hyperfiltration and progressive renal injury in SSLepRmutant rats before puberty and may be therapeutically useful in managing renal injury during prepubertal obesity.NEW & NOTEWORTHY Childhood/prepubertal obesity is a public health concern that is associated with early signs of proteinuria. Insulin resistance has been described in obese children. However, studies investigating the role of insulin resistance during childhood obesity-associated renal injury are limited. This study provides evidence of an early relationship between insulin resistance and renal injury in a rat model of prepubertal obesity. These data also suggest that reducing insulin resistance with metformin may be renoprotective in obese children.

AMPK Activation as a Protective Mechanism to Restrain Oxidative Stress in the Insulin-Resistant State in Skeletal Muscle of Rat Model of PCOS Subjected to Postnatal Overfeeding.

Polycystic ovary syndrome (PCOS) is a common endocrinopathy in women of reproductive age, often associated with obesity and insulin resistance. Childhood obesity is an important predisposing factor for the development of PCOS later in life. Being particularly interested in the interplay between prepubertal obesity and hyperandrogenemia, we investigated the effects of early postnatal overfeeding, accomplished by reducing litter size during the period of suckling, on energy sensing and insulin signaling pathways in the gastrocnemius muscle of a rat model of PCOS-induced by 5α-dihydrotestosterone (DHT). The combination of overfeeding and DHT treatment caused hyperinsulinemia and decreased systemic insulin sensitivity. Early postnatal overfeeding induced defects at critical nodes of the insulin signaling pathway in skeletal muscle, which was associated with reduced glucose uptake in the presence of hyperandrogenemia. In this setting, under a combination of overfeeding and DHT treatment, skeletal muscle switched to mitochondrial β-oxidation of fatty acids, resulting in oxidative stress and inflammation that stimulated AMP-activated protein kinase (AMPK) activity and its downstream targets involved in mitochondrial biogenesis and antioxidant protection. Overall, a combination of overfeeding and hyperandrogenemia resulted in a prooxidative and insulin-resistant state in skeletal muscle. This was accompanied by the activation of AMPK, which could represent a potential therapeutic target in insulin-resistant PCOS patients.

Circulating microRNA levels differ in the early stages of insulin resistance in prepubertal children with obesity

AimsThe increasing prevalence of childhood obesity escalates the risk for related complications. Circulating microRNAs (miRNAs) have been suggested as good predictive markers of insulin resistance in those with obesity. The aim was to identify a circulating miRNA profile that reflects insulin resistance in prepubertal children with obesity. Material and methodsPlasma miRNAs were measured in prepubertal children (n = 63, 5–9 years) using TaqMan Advanced miRNA Human Serum/Plasma plates and then were validated by RT-qPCR. Subjects were divided into normal weight (n = 20, NW) and overweight or obese (n = 43, OW/OB) groups according to their BMI z-scores. The OW/OB group was further subdivided into insulin sensitive or metabolically healthy obese (n = 26, MHO) and insulin resistant or metabolically unhealthy obese (n = 17, MUO) according to HOMA-IR. Key findingsWhile no differences were observed in the fasting plasma glucose levels, serum insulin levels were significantly elevated in the OW/OB compared to the NW group. Of 188 screened miRNAs, eleven were differentially expressed between the NW and OW/OB groups. Validation confirmed increased circulating levels of miR-146a-5p and miR-18a-5p in the OW/OB group, which correlated with BMI z-score. Interestingly, miR-146a-5p was also correlated with HOMA-IR index. While only miR-18a-5p was upregulated in the OW/OB children, independently of their degree of insulin sensitivity, miR-146-5p, miR-423-3p and miR-152-3p were associated with insulin resistance. SignificanceThe present study provides evidence of molecular alterations that occur early in life in prepubertal obesity. These alterations may potentially be crucial for targeted prevention or prompt precision therapeutic development and subsequent interventions.

Prepubertal BMI, pubertal growth patterns, and long-term BMI: Results from a longitudinal analysis in Chinese children and adolescents from 2005 to 2016.

To assess the effects of prepubertal BMI on pubertal growth patterns, and the influence of prepubertal BMI and pubertal growth patterns on long-term BMI among Chinese children and adolescents. A total of 9606 individuals aged between 7 and 18 years from longitudinal surveys in Zhongshan city of China from 2005 to 2016 were enrolled. Age at peak height velocity (APHV) and peak height velocity (PHV) were estimated using Super-Imposition by Translation and Rotation (SITAR) model. Associations between prepubertal BMI, APHV, PHV, and long-term overweight and obesity were assessed by linear regression and multinominal logistic regression. Scatter plots were elaborated to show the associations between prepubertal BMI and pubertal growth patterns according to prepubertal BMI categories. Prepubertal BMI Z-Score was positively correlated with long-term BMI Z-Score, and negatively correlated with APHV in both sexes. In addition, there was a negative association between prepubertal BMI Z-Score and PHV in boys. With 1-year decrease in APHV, risk of long-term underweight decreased by 92%, while overweight increased by 33% in boys. Corresponding risk of long-term underweight and overweight for girls decreased by 42% and increased by 20%, respectively. High prepubertal BMI levels were associated with earlier APHV and lower PHV, and the early onset of pubertal development could increase the risks of long-term overweight and obesity at 17-18 years of age both in boys and girls. Such evidence emphasized the importance of reducing prepubertal obesity risks combined with appropriate pubertal development timing, including later APHV and higher PHV, so as to prevent the obesity and related cardiovascular diseases in adulthood.

Treatment with rapamycin reduces progressive proteinuria while inducing hyperglycemia in obese Dahl salt‐sensitive leptin‐receptor mutant rats prior to puberty

Prepubertal obesity (PPO) is now considered a risk factor for the development of proteinuria and renal injury in children. Recently, we observed the early development of renal injury in the obese SSLepRmutant strain is associated with elevations in GFR and glomerular injury prior to puberty. However, the mechanisms involved remain unclear. The mammalian target of rapamycin (mTOR) signaling pathway has been shown to contribute to various forms of renal disease. In the current study, we examined whether treatment with the mTOR inhibitor, rapamycin, reduces the early progression of renal injury in SSLepRmutant rats during PPO. Four week‐old SS and SSLepRmutant rats were treated with either vehicle (saline) or rapamycin (1.5 mg/kg/day, ip) until rats reached 8 weeks of age. At baseline, body weight was significantly higher in vehicle‐treated SSLepRmutant rats compared to SS rats and remained elevated over the course of the study (309±13 vs. 219±27 g, respectively). Treatment with rapamycin significantly reduced body weight in SSLepRmutant rats compared to vehicle SSLepRmutant rats (206±9 g). At baseline, non‐fasting blood glucose levels were similar in both SS and SSLepRmutant rats and were within normal physiological range (≤120 mg/dl). Interestingly, chronic treatment with rapamycin markedly increased blood glucose levels in SSLepRmutant rats vs. vehicle SSLepRmutant rats (438±8 vs. 123±5 mg/dl, respectively) but had no effects in SS rats. At the end of the study, plasma insulin levels were significantly elevated in vehicle‐treated SSLepRmutant rats compared to the values measured in SS rats (6±1 vs. 1±0.6 ng/dl, respectively), and rapamycin treatment only reduced plasma insulin in SSLepRmutant (2±0.7 ng/dl, respectively). At baseline, proteinuria was significantly higher in SSLepRmutant rats compared to SS rats (159±34 and 17±7 mg/day, respectively) and remained elevated throughout the study (558±79 and 73±34 mg/day, respectively). By the end of the study, rapamycin significantly reduced proteinuria in SSLepRmutant rats (225±67 mg/day). We observed a significant increase in creatinine clearance (CCr) in SSLepRmutant rats vs SS rats indicating increased GFR (4.0±0.6 vs. 0.9±0.1 ml/min, respectively). Chronic treatment with rapamycin significantly decreased CCr in SSLepRmutant rats (2.2±0.9 ml/min) while not affecting SS rats. Overall, these data suggest that treatment with rapamycin is effective in reducing progressive proteinuria via reducing GFR while reducing plasma insulin levels and contributing to hyperglycemia in obese SSLepRmutant rats.

The SSLepR mutant rat represents a novel model to study obesity-induced renal injury before puberty.

Prepubertal obesity (PPO) has emerged as a major health problem over the past few decades and is a risk factor for the development of proteinuria. The current study investigated whether the development of renal injury in the obese SSLepR mutant strain occurs before puberty. When determining the temporal changes in serum sex hormones in female and male SS and SSLepR mutant rats between 4 and 10 wk of age, we only observed significant increases in estradiol and testosterone levels in female and male SS rats at 10 wk of age than at 4 wk of age. The results suggest that studying both strains between 4 and 8 wk of age is appropriate to study the effects of PPO on renal injury in this model. Proteinuria was significantly higher in SSLepR mutant rats as opposed to the values observed in SS rats at 8 wk of age, and we did not observe any sex differences in proteinuria in either strain. The kidneys from the SSLepR mutant rats displayed significant glomerular and tubular injury and renal fibrosis versus the values measured in SS rats without any sex differences. Overall, we observed increased immune cell infiltration in the kidneys from SSLepR mutant rats compared with SS rats. Interestingly, female SSLepR mutant rats displayed significant increases in not only M1 macrophages (proinflammatory) but also M2 macrophages (anti-inflammatory) versus male SSLepR mutant rats. These results suggest the SSLepR mutant rat may be a useful model to study early progression of obesity-related renal injury before the onset of puberty.

Patterns of Early Life Weight Gain and Female Onset of Puberty.

ContextPrepubertal obesity is a well-established predictor of earlier pubertal onset, which is itself a risk factor for poor health and well-being. Identifying specific patterns of weight gain in early life may help explain differential risk for earlier pubertal onset.ObjectiveThe objective of the study was to examine patterns of weight gain across infancy and early childhood in relation to pubertal onset outcomes.Design, Setting, and ParticipantsParticipants were 426 girls in the National Institute of Child Health and Human Development Study of Early Child Care and Youth Development, a longitudinal birth cohort of children and their families followed between birth and adolescence.Main Outcome MeasuresThree pubertal onset outcomes were examined, including age at menarche and ages at Tanner stage II for dimensions of breast and pubic hair development.ResultsIn infancy (birth to 15 months), greater percent weight gain and higher birthweight predicted earlier pubertal onset for all outcomes (Ps < 0.05). In early childhood (24 months to grade 1), body mass index (BMI) trajectories reflecting BMI values that were persistently high or changed from low to high over time (vs BMI values that were stable at median or low levels), predicted younger ages at menarche and the onset of breast (Ps < 0.05), but not pubic hair (Ps > 0.05), development. All associations were independent of breastfeeding, maternal menarcheal age, and race/ethnicity.ConclusionsDistinct patterns of early life weight gain predict differential risk for earlier onset puberty. Focusing on these patterns for earlier and more targeted intervention may help lessen life course linkages between prepubertal obesity, accelerated pubertal development, and negative postpubertal outcomes.

Elevations in arterial pressure are associated with increases in plasma angiotensin III and angiotensin 1‐9 in female obese SS rats prior to puberty

Recent studies show that prepubertal obesity is associated with increased risk of hypertension in children. Moreover, previous reports have demonstrated that there is a link between the renin-angiotensin system and obesity-related hypertension via angiotensin II (Ang II) metabolism. However, to our knowledge, studies examining AngII metabolism during the development of hypertension associated with prepubertal obesity are limited. Therefore, the current study examined whether there are sex differences in arterial pressure and AngII metabolism in lean Dahl salt-sensitive (SS) and obese SS leptin receptor mutant (SSLepRmutant) rats. Four week-old female and male lean SS and obese SSLepRmutant rats (n=5 rats per group) were implanted with telemetry transmitters to measure MAP until the rats reached 8 weeks of age. Over the course of the study, we did not detect any differences MAP between female and male SS rats (115±2 and 120±2 mmHg, respectively). MAP was similar in male SSLepRmutant rats compared to their wild-type littermates (118±6 mmHg). However, we observed a marked increase in MAP in female SSLepRmutant rats compared to the other groups (144±7 mmHg; p<0.05 vs. all groups). At the end of the study, plasma was collected and analyzed for AngII metabolites (AngII, Ang(1-7), AngIII, AngIV, Ang(1-5) and Ang(1-9); via mass spectrometry). Interestingly, we did not observe any sex or strain differences in plasma AngII levels between lean SS and obese SSLepRmutant rats. Additionally, similar results were seen when measuring the plasma levels of Ang(1-7), AngIV, and Ang(1-5). However, AngIII and Ang(1-9) levels were more than two-fold higher in female obese SSLepRmutant rats versus their lean SS littermates and male obese SSLepRmutant counterparts (p<0.05 vs. all groups). Overall, these data indicate that the elevations in arterial pressure in female obese SSLepRmutant rats is associated with alterations in angiotensin metabolism with increases in plasma levels of AngIII and Ang(1-9). Additionally, further studies are needed to investigate the roles of AngIII and Ang(1-9) and their signaling pathways in the early development of hypertension in female obese SSLepRmutant rats prior to puberty.

Early life household intactness and timing of pubertal onset in girls: a prospective cohort study

BackgroundGirls who experience early-life familial stress may have heightened risk of early puberty, which has adverse implications for adolescent and adult health. We assessed the association between household intactness and pubertal onset using a racially/ethnically diverse cohort of girls from Northern California.MethodsA prospective cohort study of 26,044 girls born in 2003-10. Girls living with both parents from birth up to 6 years were considered to come from “intact” households while others constituted “non-intact” households. Pubertal development was measured using pediatrician-assessed Tanner staging for breast and pubic hair. Pubertal onset was defined as the transition from Tanner Stage 1 to 2+ for breast (thelarche) and pubic hair (pubarche). Menarche data was collected from routine well-child questionnaires. Weibull regression models accommodating left, right, and interval censoring were used to determine risk of earlier thelarche and pubarche, and logistic regressions were used to assess the risk of early menarche (age < 12).ResultsGirls exposed to non-intact households before age 2 years were at increased risk for earlier thelarche and pubarche with significant effect modification by race/ethnicity, compared with girls from intact households. The associations were strongest among Black girls (adjusted hazard ratio [HR]: 1.60, 95% confidence interval [CI]: 1.29,1.98; HR: 1.42, 95%CI: 1.15,1.77 for thelarche and pubarche, respectively). There were no significant associations among Asian/Pacific Islanders. Girls who lived in non-intact households before age 2 years were also at increased risk for earlier menarche, but without race/ethnic interaction. Adjustment for prepubertal obesity did not change these associations. Associations between living in non-intact households after age 2 years and early puberty were weaker but still significant.ConclusionsExposure to a non-intact household early in life may increase the risk of early puberty in girls. Future psychosocial interventions focused on improving family cohesiveness and efforts to reduce childhood stress among families that are non-intact may mitigate these negative associations, thereby preventing future adverse health effects of early puberty and health disparities.

Molecular phenomics of a high-calorie diet-induced porcine model of prepubertal obesity

As obesity incidence is alarmingly rising among young individuals, we aimed to characterize an experimental model of this situation, considering the similarity between human and porcine physiology. For this reason, we fed prepubertal (63 days old) Duroc breed females (n=21) either with a standard growth diet (3800 kcal/day) or one with a high-calorie content (5200 kcal/day) during 70 days. Computerized tomography, mass-spectrometry-based metabolomics and lipidomics, as well as peripheral blood mononuclear cell transcriptomics, were applied to define traits linked to high-calorie intake. Samples from a human cohort confirmed potential lipidomic markers. Compared to those fed a standard growth diet, pigs fed a high-calorie diet showed an increased weight gain (13%), much higher adiposity (53%), hypertriacylglyceridemia and hypercholesterolemia in parallel to insulin resistance. This diet induced marked changes in the circulating lipidome, particularly in phosphatidylethanolamine-type molecules. Also, circulating specific diacylglycerol and monoacylglycerol contents correlated with visceral fat and intrahepatic triacylglycerol concentrations. Specific lipids associated with obesity in swine (mainly belonging to glycerophospholipid, triacylglyceride and sterol classes) were also linked with obesity traits in the human cohort, reinforcing the usefulness of the chosen approach. Interestingly, no overt inflammation in plasma or adipose tissue was evident in this model. The presented model is useful as a preclinical surrogate of prepubertal obesity in order to ascertain the pathophysiology interactions between energy intake and obesity development.

Depletion of macrophages with clodronate partially reduces the progression renal injury in obese Dahl salt‐sensitive rats during prepubertal obesity

Prepubertal obesity (PPO) is now considered a risk factor for the development of proteinuria and renal injury in children. Recently, we reported that, prior to puberty, Dahl salt‐sensitive leptin receptor mutant (SSLepRmutant) rats display proteinuria and renal injury as early as 6 weeks of age independent of hyperglycemia and elevations in arterial pressure. Moreover, the early development of renal injury was associated with an increase in the renal infiltration of macrophages in the SSLepRmutant strain compared to their lean SSWT counterparts (39±14 vs. 11±3 % gated, respectively; p&lt;0.05 vs. SSWT). Therefore, the current study examined whether depletion of macrophages with clodronate would reduce renal injury in the SSLepRmutant strain during PPO. Four week‐old SSWT and SSLepRmutant rats were separated into four groups (n=4/group): (1) SSWT and (2) SSLepRmutant rats treated with vehicle‐PBS and (3) SSWT and (4) SSLepRmutant rats treated with clodronate (50 mg/kg, i.p., twice/week) for 4 weeks. While administration of clodronate did not have an effect in SSWT rats, clodronate significantly depleted macrophages in the kidneys of SSLepRmutant rats compared to vehicle‐treated rats without altering the monocyte population (8±4 versus 33±10 % gated, respectively; p&lt;0.05 vs. vehicle). At baseline, protein excretion was significantly higher in SSLepRmutant rats compared to SSWT rats (70±14 vs. 10±3 mg/day, respectively; p&lt;0.05 vs. SSWT) that further increased over the course of the study (335±82 vs. 45±14 mg/day, respectively; p&lt;0.05 vs. SSWT). Clodronate had no effect on the progression of proteinuria or renal histopathology in SSWT rats. After 2 weeks of treatment with clodronate, protein excretion was markedly reduced in the SSLepRmutant strain (86±36 vs. 200±35 mg/day; p&lt;0.05 vs. vehicle). However, after 4 weeks of treatment, the effect of clodronate was no longer observed in the SSLepRmutant strain (270±90 vs. 335±82 mg/day). The kidneys from SSLepRmutant rats displayed glomerular injury with increased mesangial expansion and renal fibrosis versus SSWT rats. Interestingly, treatment with clodronate had no effect on glomerular injury but significantly decreased renal fibrosis in the SSLepRmutant strain compared to their vehicle‐treated obese counterparts. Overall, these data indicate that the early development of renal injury in the SSLepRmutant strain is associated with macrophage infiltration, which can be blunted by chronic macrophage depletion.Support or Funding InformationThis study was supported by GM104357 and DK109133.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Association of prepubertal obesity with pubertal development in Chinese girls and boys: A longitudinal study.

ObjectivesThe purpose of this study was to examine the association of prepubertal body mass index (BMI) and weight status with pubertal development in boys and girls in Chongqing, China.MethodsIn a longitudinal study, 1237 students (695 boys and 542 girls) were recruited from Chongqing, China, and examined at baseline, then followed every 6 months for three and a half years. Height, weight, testicular volume, and breast development were measured at every examination. Age of first spermatorrhea and menarche were obtained from self‐report. Subjects were divided into normal weight, overweight, and obese groups according to baseline BMI. Multivariable Cox regression analysis was used to examine the association of BMI and weight status with pubertal development.ResultsIn girls, higher prepubertal BMI increased the chance of earlier menarche (hazards ratio (HR): 1.205, 95% confidence interval (95% CI): 1.151‐2.261) and breast development (HR: 1.092, 95% CI: 1.045‐1.142). Girls in the overweight (HR: 2.605, 95% CI: 1.716‐3.956) and obese (HR: 2.565, 95% CI: 1.603‐4.103) groups had an increased risk of early menarche compared with those in the normal weight group, while only overweight was associated with an increased risk for earlier breast development (HR: 1.469, 95% CI: 1.024‐2.108). In boys, higher prepubertal BMI was significantly associated with the timing of first spermatorrhea (HR: 1.054, 95% CI: 1.004‐1.106) and testicular development (HR: 1.098, 95% CI: 1.063‐1.135). Overweight (HR: 1.672, 95% CI: 1.204‐2.322) and obesity (HR: 1.598, 95% CI: 1.135‐2.249) increased the hazard of earlier testicular development compared with the normal weight group, while no significant differences were detected among the three weight groups in terms of time to first spermatorrhea.ConclusionsHigher prepubertal BMI was associated with earlier puberty in both Chinese boys and girls.

PO-289 Lipidomic analysis of blood serum from prepubertal boys with different BMI

Objective Childhood obesity is a worldwide health problem which may causes metabolic diseases such as hyperglycemia, hyperlipidemia, hypertension and hyperuricemia. It is well know that lipid metabolites regulate fatty acid and glucose homeostasis. Lipidomics is the comprehensive analysis of lipid metabolites which include their quantitation and metabolic pathways. The intention of this study is to identify the circulating lipid species which are altered in obese prepubertal boys.&#x0D; Methods A total number of 72 boys aged 10.28 ±0.69 years old were included into this study, and divided into normal(NC), overweight(OW) and obese group(OB). The degree of maturation of all boys were measured by bone age and sex hormones. Then we measured the form indexes, blood lipids, blood glucose level to identify the current state of all boys. Serum indexes were detected by CLIA and ELISA methods. A lipidomic method was established by using a Waters Acquity UPLCI-Class liquid system combined with Waters Xevo G2-SQ-TOF mass spectrometry system. The identification and analysis of lipid metabolites were complished by using MassLynx 4.1, Progenesis QI software and LipidMaps database. Statistical analyzes were performed using SPSS22.0 software.&#x0D; Results (1)The waist-to-hip ratio, bone age and HDL-c levels ware significant lower in OW and OB groups. The TG level was significant higner in OB group. The DHEA and SHBG levels was significant higner in OW and OB groups and the other sex hormones are not .&#x0D; (2) In this study, 153 most significant different lipid metabolites were founded, incluing 3 diacylglycerol, 32 triglyceride, 1 Phosphatidyl cholines, 1 Phosphatidylinositol, 3 Sphingomyelin, 1 Ceramide which significant higher in OW&amp;OB group; 4 diacylglycerol, 17 Phosphatidic acid, 32 Phosphatidyl cholines, 4 Phosphatidylinositol, 13 Phosphatidylserine, 18 Phosphatidyl ethanolamine, 3 Phosphoglycerides, 13 Sphingomyelin and 6 Ceramide which significant lower in OW&amp;OB group.&#x0D; Among all this metabolites, 8 lipids (fold change ≥5) were founded as the significant biomarkers related prepubertal obesity , including 1 Phosphatidyl cholines, 1 phosphatidylserine, 2 sphingomyelin and 4 Triglyceride. What’s more, the level of SM(d16:1/24:0) and TG(15:0/17:1/20:3) which measured by UPLC-QTOF/MS are highly positive correlated with the level of serum SHBG; PC(18:0/0:0) and TG(16:1/18:0/20:3) are highly negtive correlated with serum SHBG.&#x0D; Conclusions Overweight and obese prepubertal boys showed disorder in lipid metabolism and bone growth. The lipidomic results showed lower SHBG level is related with the disorder of lipid metabolism. We suggest that further studies on these metabolites could help us gain a better understanding of the relationship between obesity and growth disorder.

Influence of puberty timing on adiposity and cardiometabolic traits: A Mendelian randomisation study.

BackgroundEarlier puberty is widely linked with future obesity and cardiometabolic disease. We examined whether age at puberty onset likely influences adiposity and cardiometabolic traits independent of childhood adiposity.Methods and findingsOne-sample Mendelian randomisation (MR) analyses were conducted on up to 3,611 white-European female and male offspring from the Avon Longitudinal Study of Parents and Children (ALSPAC) cohort recruited at birth via mothers between 1 April 1991 and 31 December 1992. Time-sensitive exposures were age at menarche and age at voice breaking. Outcomes measured at age 18 y were body mass index (BMI), dual-energy X-ray absorptiometry–based fat and lean mass indices, blood pressure, and 230 cardiometabolic traits derived from targeted metabolomics (150 concentrations plus 80 ratios from nuclear magnetic resonance [NMR] spectroscopy covering lipoprotein subclasses of cholesterol and triglycerides, amino acids, inflammatory glycoproteins, and others). Adjustment was made for pre-pubertal BMI measured at age 8 y. For negative control MR analyses, BMI and cardiometabolic trait measures taken at age 8 y (before puberty, and which therefore cannot be an outcome of puberty itself) were used. For replication analyses, 2-sample MR was conducted using summary genome-wide association study data on up to 322,154 adults for post-pubertal BMI, 24,925 adults for post-pubertal NMR cardiometabolic traits, and 13,848 children for pre-pubertal obesity (negative control). Like observational estimates, 1-sample MR estimates in ALSPAC using 351 polymorphisms for age at menarche (explaining 10.6% of variance) among 2,053 females suggested that later age at menarche (per year) was associated with −1.38 kg/m2 of BMI at age 18 y (or −0.34 SD units, 95% CI −0.46, −0.23; P = 9.77 × 10−09). This coefficient attenuated 10-fold upon adjustment for BMI at age 8 y, to −0.12 kg/m2 (or −0.03 SDs, 95% CI −0.13, 0.07; P = 0.55). Associations with blood pressure were similar, but associations across other traits were small and inconsistent. In negative control MR analyses, later age at menarche was associated with −0.77 kg/m2 of pre-pubertal BMI measured at age 8 y (or −0.39 SDs, 95% CI −0.50, −0.29; P = 6.28 × 10−13), indicating that variants influencing menarche also influence BMI before menarche. Cardiometabolic trait associations were weaker and less consistent among males and both sexes combined. Higher BMI at age 8 y (per 1 kg/m2 using 95 polymorphisms for BMI explaining 3.4% of variance) was associated with earlier menarche among 2,648 females (by −0.26 y, 95% CI −0.37, −0.16; P = 1.16 × 10−06), likewise among males and both sexes combined. In 2-sample MR analyses using 234 polymorphisms and inverse variance weighted (IVW) regression, each year later age at menarche was associated with −0.81 kg/m2 of adult BMI (or −0.17 SD units, 95% CI −0.21, −0.12; P = 4.00 × 10−15). Associations were weaker with cardiometabolic traits. Using 202 polymorphisms, later menarche was associated with lower odds of childhood obesity (IVW-based odds ratio = 0.52 per year later, 95% CI 0.48, 0.57; P = 6.64 × 10−15). Study limitations include modest sample sizes for 1-sample MR, lack of inference to non-white-European populations, potential selection bias through modest completion rates of puberty questionnaires, and likely disproportionate measurement error of exposures by sex. The cardiometabolic traits examined were heavily lipid-focused and did not include hormone-related traits such as insulin and insulin-like growth factors.ConclusionsOur results suggest that puberty timing has a small influence on adiposity and cardiometabolic traits and that preventive interventions should instead focus on reducing childhood adiposity.

Inflammatory markers in relation to pre-pubertal obesity

Abstract Background According to the WHO, current childhood obesity trends are expected to increase to 70 million by 2025. Childhood obesity is becoming a major epidemic with adipokines-TNF-α, IL-6, leptin, and adiponectin-being potentially implicated in the pathogenesis. Methods We conducted a literature search of PubMed clinical trials and articles where we searched key terms: ‘pre-pubescent obese children’ cross referenced with ‘TNF-α’ or ‘IL-6’ or ‘hs-CRP’ or ‘adiponectin’. Research Thirty-six articles remained in the review after our exclusion criteria was applied. Most of these showed a positive correlation of obesity with TNF-α, IL-6, and hs-CRP. In addition, the research showed a negative correlation with adiponectin. There was one study that we found that showed TNF-α to not be related to obesity and another that showed adiponectin to have a positive correlation rather than negative correlation with obesity. Another contributing study that we evaluated showed that TNF-α causes a decrease in C/EBP-alpha which are gene promoters that downregulate myc. By downregulating this cell cycle regulator there is potential for proliferation of cells leading to increased risk for both obesity and cancer. TNF-α, is one of the primary inflammatory markers that has been implicated in obesity; thus, showing that it could have diagnostic factors in cancer through this downregulation of myc. Conclusion A possible consideration for future research is to evaluate the possible relationship between inflammatory markers discussed as diagnostic factors for pediatric cancer. With this potential innovative method, we as a research community can lessen the burden cancer has put on our society.

Sex Differences in the Development of Renal Injury in Obese Dahl Salt‐Sensitive Leptin Receptor Mutant Rats During Prepubertal Obesity

Recent studies show that prepubertal obesity (PPO) is associated with increased risk of renal injury in children. Furthermore, nearly 40% of obese children develop microalbuminuria. Additionally, studies examining the impact of sex on the development of renal injury associated with PPO have been limited. Recently, we reported that, prior to puberty, male Dahl salt‐sensitive leptin receptor mutant (SSLepR mutant ‐ PPO model) rats display proteinuria and podocyte injury by 6 weeks of age independent of hyperglycemia and elevations in arterial pressure. However, female PPO rats were not examined during the same time period. Therefore, in the current study, we investigated whether there were sex differences during the development of renal injury associated with prepubertal obesity. Proteinuria was significantly higher in female and male PPO rats as opposed to the values observed in Control rats at 4 weeks of age (65±12 and 64.7±13 vs 2±1 and 2±0.3 mg/day, respectively, n=4). While we observed minimal increases in proteinuria in Control rats at 8 weeks of age, proteinuria increased to 266.6±65 and 376±56 mg/day in female and male PPO rats, respectively. The kidneys from the PPO rats displayed significant glomerular injury and marked renal fibrosis when compared to the values measured in Control rats. Interestingly, the development of proteinuria and glomerular injury in the PPO model was associated with increased infiltration of CD68+ macrophages expressing Lamp2 and CD36, markers for lysosomes and fatty acid translocase, respectively. Additionally, we assessed renal inflammation via the Bio‐Plex Pro Rat Cytokine 23‐Plex Immunoassay and observed that macrophage inflammatory protein‐3a (MIP‐3a) levels were significantly elevated in both female and male PPO rats (3059±364 and 2545±333 ng/mg of protein, respectively) compared to the values measured in Control rats (1579±291 and 1138±95 ng/mg of protein, respectively). Overall these data indicate that the early development of renal injury in the PPO model might be due to macrophage infiltration stimulating progressive proteinuria independent of hypertension and diabetes.Support or Funding InformationThis study was supported by P20GM104357 and R01 DK109133‐01.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.