O objetivo deste estudo foi avaliar o fornecimento crônico de leptina recombinante ovina (oLeptina) e do nível de energia da dieta na idade, peso vivo (PV), escore de condição corporal (ECC) e composição corporal à puberdade, assim como avaliar seus efeitos no desenvolvimento dos folículos ovarianos e no consumo de matéria seca (CMS). Foram utilizadas 36 novilhas da raça Nelore, com média de 18 a 20 meses de idade, 276,1 ± 17,9 kg PV e ECC de 4,7 ± 0,46, distribuídas aleatoriamente em três tratamentos: A) Dieta de alta energia; B) Dieta de baixa energia, BL) Dieta de baixa energia com administração subcutânea de oLeptina. Os animais foram alojados de 2 baias coletivas de acordo com a dieta oferecida. As dietas foram formuladas para promover um ganho de peso médio diário (GMD) de 0,3 kg PV/dia e 1,0 kg PV/dia. O controle de consumo foi feito através da pesagem diária das sobras e manutenção dessas entre 5 e 10% do total oferecido. Os animais foram pesados e tiveram o ECC avaliado duas vezes por semana, para acompanhamento do GMD. Foi administrado 12 g de óxido de cromo/animal/dia por deglutição forçada por 10 dias, com coleta de amostras de fezes, dieta e sobras nos últimos 5 dias, para estimativa do consumo individual de MS e energia, através da determinação do cromo nas fezes e do FDNi nas fezes, dietas e sobras. O grupo BL recebeu 4,8 µg de oLeptina/kg PV, via subcutânea, duas vezes ao dia (6:00 e 18:00 horas) por 56 dias, enquanto os grupos A e B receberam 2 ml de solução salina. O diâmetro máximo do folículo dominante (FD) e a presença de corpo lúteo (CL) foram avaliados através de ultrassonografia transretal duas vezes por semana, até o momento da puberdade. No momento da ultrassonografia, foram coletadas amostras de sangue, por punção da veia jugular, para dosagem da concentração sérica de progesterona. A idade à puberdade foi considerada como a idade na primeira detecção de um CL, confirmado como sendo funcional por dosagem de progesterona acima de 1 ng/ml. Após a confirmação da puberdade os animais foram abatidos para estimativa da composição corporal, através da determinação do teor de água em cortes da 9a-10a-11a costelas. O maior teor de energia na dieta reduziu a idade e aumentou o ECC à puberdade (P<0,05). A leptina não teve efeito na idade, PV ou ECC à puberdade (P>0,05). Tanto o maior consumo de energia quanto a leptina aumentaram a velocidade de crescimento e determinaram maior diâmetro médio do FD (P<0,05), entretanto a velocidade de crescimento do FD do grupo BL voltou a diminuir, igualando-se à do grupo BL, após cerca de 30 dias de tratamento, comportando-se de forma quadrática à análise de regressão. O maior consumo de energia determinou maior teor de extrato etéreo e menores teores de proteína, matéria seca e matéria mineral no corpo vazio, além de maior espessura de gordura subcutânea e área de olho de lombo na carcaça (P<0,05). A aplicação de leptina não alterou a composição corporal das novilhas à puberdade (P>0,05). Não houve diferença no CMS (kg MS/dia) entre os grupos, entretanto o grupo A teve menor CMS em % PV, além de maior consumo de energia digestível, metabolizável e líquida para ganho (P<0,05). A leptina não reduziu o CMS das novilhas (P>0,05) tanto em kg MS/dia quanto em % PV. A energia acelera a obtenção da puberdade e altera a composição corporal à puberdade de novilhas zebuínas. A aplicação de leptina não acelerou a obtenção da puberdade de novilhas zebuínas em baixo consumo de energia, mas aumentou temporariamente a taxa de crescimento folicular desses animais. / This study was carried out to evaluate the effects of chronic administration of recombinant ovine leptin (oLeptin) and the energy level of the diet on age, body weight (BW), body condition score (BCS) and body composition at puberty, as well as to evaluate its effects on dominant follicle (DF) development and dry matter (DM) intake. Thirty six Nellore heifers, 18 to 20 months old, with 276.1 ± 17.9 kg BW and BCS of 4.7 ± 0.46 were randomly distributed into three treatments: H) High energy diet; L) Low energy diet; LL) Low energy diet with subcutaneous administration of oLeptin. Heifers were housed in two collective pens according to the diet offered. Diets were formulated to promote an average daily gain (ADG) of 0.3 kg BW/day and 1.0 kg BW/day. Intake was controlled daily by weighting the orts and keeping it between 5 and 10% of the total offered. Heifers were weighed and had their BCS was evaluated twice weekly, in order to control the ADG. Heifers received 12 g of chromic oxide/animal/day by forced swallowing for 10 days, while feces, diet and orts were sampled in the last 5 days, in order to estimate individual DM and energy intake, which was done by feces determination of chromic oxide, and diet and, feces and orts determination of iNDF. The LL group received 4.8 µg oLeptina/kg BW, subcutaneously, twice a day (at 06:00 and 18:00), for 56 days, while H and L groups received 2 ml of saline solution. Maximum DF diameter and presence of corpus luteum (CL) were evaluated twice weekly by transrectal ultrasound, until heifers achieved puberty. At the time of ultrasound evaluation, blood was sampled by jugular venipuncture for serum progesterone determination. Age at puberty was considered as age at first detection of a CL confirmed to be functional by serum progesterone above 1 ng/ml. After puberty confirmation heifers were slaughtered for body composition estimation, which was done by water determination on 9a-10a-11a rib cuts. High energy intake reduced age and enhanced BCS at puberty (P<0.05). Leptin administration did not affect age, BW or BCS at puberty (P>0.05). The high energy intake as well as leptin administration accelerated the DF growth and determined greater DF diameter (P<0.05), however the rate of growth on the LL group decreased after around 30 days of treatment equaling the rate of growth of the L group, and behaving in a quadratic manner at regression analysis. High energy intake enhanced ether extract and lowered protein and minerals proportion on empty body (P<0.05). It also enhanced carcass subcutaneous fat and the longissimus muscle area (P<0.05). Leptin administration did not alter the body composition of heifers at puberty (P>0.05). There was no difference on DM intake (kg DM/day) between groups, however the H group had higher DM intake in terms of % BW, as well as higher intake of digestible, metabolizable and net energy for gain (P<0.05). Leptin did not reduce DM intake neither in terms of kg BW/day nor % BW (P>0.05). Energy intake accelerates the onset of puberty and alters body composition at puberty of zebu heifers. Leptin administration did not accelerate puberty onset of zebu heifers receiving low energy diet, but temporarily enhanced the follicular growth rate of these animals.

Indiana University-Purdue University Indianapolis (IUPUI) / Primary cilia are solitary cellular appendages that function as signaling centers for cells in adult energy homeostasis. Here in chapter 1, I introduce cilia and how dysfunction of these conserved organelles results in ciliopathies, such as Bardet-Biedl Syndrome (BBS), which present with childhood obesity. Furthermore, conditional loss of primary cilia from neurons in the hypothalamus leads to hyperphagia and obesity in mouse models of ciliopathies. Classically, cilia coordinate signaling often through specific G-protein coupled receptors (GPCRs) as is the case in both vision and olfaction. In addition, neurons throughout the brain including hypothalamic neurons possess primary cilia whose dysfunction contributes to ciliopathy-associated obesity. How neuronal cilia regulate the signaling of GPCRs remains unclear and many fundamental cell biology questions remain about cilia mediated signaling. For example, how cilia coordinate signaling to influence neuronal activity is unknown. To begin to address some of these cell biology questions around neuronal cilia, chapter 2, describes the development and use of a system for primary neuronal cultures from the hypothalamus. Using this system, we found that activation of the cilia regulated hedgehog pathway, which is critical in development, influenced the ability of neurons to respond to GPCR ligands. This result highlights the role of the developmentally critical hedgehog pathway on terminally differentiated hypothalamic neurons. One challenge facing the cilia field is our ability to assess cilia in large numbers without potential bias. This is especially true in tissues like the brain, where cilia appear to have region-specific characteristics. Work included in Chapter 3 describes the use of a computer-assisted artificial intelligence (Ai) approach to analyze cilia composition and morphology in a less biased and high throughput manner. Cilia length and intensities are important parameters for evaluation of cilia signaling. Evidence suggests that activation of some ciliary GPCRs results in shortening of cilia whereas deviations from normal cilia length in mutant phenotypes affects normal physiological processes such as decreased mucociliary clearance. Therefore, to analyze a large number of cilia, we describe the use of the Ai module from in vitro and in vivo samples in a reproducible manner that minimizes user bias. Using this approach, we identified that Mchr1 expression is significantly stronger in the cilia of paraventricular nucleus than that in the arcuate nucleus of adult mice. Work in Chapter 4 continues to explore the integration between hedgehog pathway and ciliary GPCR signaling in the central nervous system, and its relevance with energy homeostasis. We evaluated the hedgehog ligand in the plasma of mice in acute and long-term metabolic changes and identified that the activity of the ligand changed under altered metabolic conditions. We also developed a genetic mouse model where hedgehog signaling was constitutively active in neuronal cilia. These mice become hyperphagic and obese. These results further emphasize the potential role of the hedgehog signaling pathway in regulation of feeding behavior in adult vertebrates. Overall, results from this work will provide a better understanding of the defects not only underlying ciliopathy-associated obesity but may also reveal more common mechanisms of centrally mediated obesity. In addition, the tools I have developed will help in understanding how neuronal cilia are used for intercellular communications and ultimately how they regulate behaviors like feeding.

No description available.

There is increasing recognition of the relationship between depression and obesity in the pediatric population and recently, there has been a focus on inflammation as a potential link. Both conditions are considered to be pro-inflammatory states, and certain inflammatory markers are linked to depression in obese adults and vice versa. Leptin has also been implicated in depression as a potential mediator between inflammation and depression. Brain derived neurotrophic factor (BDNF), which is associated with depression and obesity, is influenced by inflammation and leptin in animal models as well. Few studies have examined the interactions between depression, adiposity, and biological markers in obese youth and therefore, our objective was to explore the determinants of depression in obese youth in a clinical setting. We studied 244 youth aged 8-17 years (125 girls, 119 boys) at the time of entry to a weight management program, as part of a prospective, longitudinal study. The CES-DC depression-screening tool was used to assess depressive symptoms, and a participant was classified as having high depressive symptoms if the CES-DC score ≥15 or taking antidepressants. Questionnaires assessed socio-demographic factors and puberty while adiposity was measured using dual-energy X-ray absorptiometry (DXA). Inflammatory markers (IL-6, TNFα, CRP, IL-10), leptin, and BDNF were quantified by immunoassays. Of the 244 participants, 8 were on antidepressants and 88 (36.4%) met the criteria for high depressive symptoms. We confirmed previous findings that household income and body fat were important determinants of depressive symptoms. However for the first time, it was identified that leptin levels predicted CES-DC score independent of body fat. Neither inflammatory markers nor BDNF were significantly related to depression scores. Our findings suggest that leptin may mediate the relationship of adiposity and depression but it is uncertain if this is related to direct action or to the phenomenon of leptin resistance. / Thesis / Master of Science (MSc) / Obesity has a significant impact on depression in children and adolescents. Inflammation – the body’s response to injury – is measured through markers in the blood and leptin – the marker of body fat – have shown to be related to depression. Research indicates that depression influences these factors to act on obesity. However, research on the interactions of biological and socio-demographic factors with depression in youth with obesity is lacking. Therefore, our objective was to explore the impact of these factors on depression in obese youth entering into a weight management program. Using a depression-screening tool, we studied 244 youth under 18 years and confirmed that household income and body fat were important factors of depression. However for the first time, we found leptin influenced depression regardless of the amount of fat present suggesting that depression acts on obesity through leptin but it is uncertain how this occurs and further research is warranted.

No description available.

No description available.

<p>Examining the effect of a modernized collaborative care intervention for depression consisting of both behavioral and pharmacologic treatments on 12-month change in individual somatic depressive symptoms (hyperphagia, poor appetite, hypersomnia, and disturbed sleep) and 12-month change in</p> <p>cardiometabolic biomarkers (HOMA-IR, BMI, hsCRP, leptin, and ghrelin). Further examining whether 12-month change in individual somatic depressive symptoms mediates the eIMPACT intervention’s effect on 12-month change in cardiometabolic biomarkers.</p>

Previous studies have shown markedly lower birth weight among infants of South Asian origin compared with those of White European origin. Whether such differences mask greater adiposity in South Asian infants and whether they persist across generations in contemporary UK populations is unclear. Our aim was to compare birth weight, skinfold thickness and cord leptin between Pakistani and White British infants and to investigate the explanatory factors, including parental and grandparental birthplace. METHODS: We examined the differences in birth weight and skinfold thickness between 4649 Pakistani and 4055 White British infants born at term in the same UK maternity unit and compared cord leptin in a subgroup of 775 Pakistani and 612 White British infants. RESULTS: Pakistani infants were lighter (adjusted mean difference -234 g 95% CI -258 to -210) and were smaller in both subscapular and triceps skinfold measurements. The differences for subscapular and triceps skinfold thickness (mean z-score difference -0.27 95% CI -0.34 to -0.20 and -0.23 95% CI -0.30 to -0.16, respectively) were smaller than the difference in birth weight (mean z-score difference -0.52 95% CI -0.58 to -0.47) and attenuated to the null with adjustment for birth weight (0.03 95% CI -0.03 to 0.09 and -0.01 95% CI -0.08 to 0.05, respectively). Cord leptin concentration (indicator of fat mass) was similar in Pakistani and White British infants without adjustment for birth weight, but with adjustment became 30% higher (95% CI 17% to 44%) among Pakistani infants compared with White British infants. The magnitudes of difference did not differ by generation. CONCLUSIONS: Despite being markedly lighter, Pakistani infants had similar skinfold thicknesses and greater total fat mass, as indicated by cord leptin, for a given birth weight than White British infants. Any efforts to reduce ethnic inequalities in birth weight need to consider differences in adiposity and the possibility that increasing birth weight in South Asian infants might inadvertently worsen health by increasing relative adiposity.

Obesity is a worldwide epidemic increasing at an alarming rate among youth who are facing similar health problems as adults. Sleep Apnea Syndrome (SAS) is an underdiagnosed comorbidity of obesity, characterized by repetitive nocturnal interruptions in breathing. Obesity is associated with delayed skeletal maturation in overweight youth, but mechanisms contributing to this problem are unclear. Obesity and SAS both have been shown to disrupt regulatory hormones and cytokines that influence bone accretion during adolescence. PURPOSE: The purpose of this study was to assess the combined effects of excess body weight and SAS on bone mineral density (BMD) and content (BMC), bone turnover, and on the regulatory hormones leptin and IGF-1 known to potentially influence bone accretion during adolescence. METHODS: Men aged 18-28 years were assigned to groups as follows: normal weight controls (CON: AHI <3, n=8); overweight without SAS (OWT: BMI < 26 kg/m2 and AHI <3, n=9); and overweight with SAS (SAS: BMI >26 kg/m2 and AHI >5, n=8). The apnea/hypopnea index (AHI) expresses the score for disrupted nighttime breathing events/hr and was obtained in this study with results from a home sleep screening test. Health history and Epworth Sleepiness Scale (ESS) questionnaires also were administered. Bone mineral parameters and body composition variables were measured with dual-energy X-ray absorptiometry. Serum osteocalcin, leptin, IGF-1, and NTx-1 were measured, respectively, by radioimmunoassay and enzyme-linked immunoabsorbent assay. RESULTS: Fat-free mass, intra-abdominal fat, and fat mass were higher in the SAS and OWT groups (p<0.03). ESS scores revealed that SAS individuals were sleepier than CON and OWT groups (p<0.009). Total body and site-specific BMD and BMC values (lumbar spine, hip, and forearm) were similar between groups and did not relate to the estimated AHI score. Serum OC and NTx-1 did not differ between groups. Leptin levels were 30% higher in OWT and SAS than in the CON group (p<0.02), but did not correlate with the AHI score. Across all subjects (n=25), only lumbar spine BMC (p<0.005) was correlated to AHI (r=-.52; p<0.01). The preponderance of this relationship between AHI and lumbar spine BMC was attributable to the close inverse association of these two variables within the SAS group (r = -.81; p<0.001). CONCLUSION: The effects of SAS were not influenced by the amount of whole-body, intra-abdominal adiposity or lean body mass. Neither leptin nor IGF-1 predicted bone status across all groups. Daytime fatigue and sleepiness, a cardinal symptom of SAS, combined with overweight may contribute to lower lumbar BMC by chronically reducing weight-bearing physical activity and thereby reduce exposure time for mechanical loading of the spine in affected individuals. Further research is needed to explore the biochemical, physiological, and apparently the physical activity implications of SAS on skeletal status and turnover. / Master of Science

Diese Arbeit beinhaltet Untersuchungen zu den unterschiedlichen Isoformen des Leptinrezeptors und dessen Regulation in primären humanen Hepatozyten. Leptin und der Leptinrezeptor nehmen in der Physiologie des menschlichen Energiehaushaltes eine wesentliche Funktion ein und sind an der Pathogenese der Adipositas mit Folgeerkrankungen wie der Entwicklung einer Fettleber beteiligt. Es wird erstmalig geprüft inwieweit das Modellsystem primärer humaner Hepatozyten für Analysen der Leptinrezeptor-Expression und der Abspaltung von löslichem Leptinrezeptor geeignet ist. Weiterhin werden untersucht, welchen Einfluss endokrine Regulatoren wie Dexamethason, Leptin und Glucagon auf die isoformspezifischen Rezeptormengen in primären Hepatozyten haben und wie der Rezeptor unter Apoptose reguliert ist, welche durch die lipotoxischen Effekte der freien Fettsäure Palmitat und den Apoptoseinduktor Staurosporin induziert wird. Hierdurch können Rückschlüsse auf eine möglicherweise veränderte Wirksamkeit des Leptins in der Leber gezogen werden.